WorldWideScience

Sample records for hot arid regions

  1. Biomimicry as an approach for sustainable architecture case of arid regions with hot and dry climate

    Science.gov (United States)

    Bouabdallah, Nabila; M'sellem, Houda; Alkama, Djamel

    2016-07-01

    This paper aims to study the problem of thermal comfort inside buildings located in hot and arid climates. The principal idea behind this research is using concepts based on the potential of nature as an instrument that helps creating appropriate facades with the environment "building skin". The biomimetic architecture imitates nature through the study of form, function, behaviour and ecosystems of biological organisms. This research aims to clarify the possibilities that can be offered by biomimicry architecture to develop architectural bio-inspired building's design that can help to enhance indoor thermal ambiance in buildings located in hot and dry climate which helps to achieve thermal comfort for users.

  2. To enhance the cooling comfort condition in home by water spray upon the roof in hot arid region experimental work

    International Nuclear Information System (INIS)

    Abdul Sada, Ghanim Kadhem; Al Shammaa, Mostafa Khairy

    2006-01-01

    Fossil fuel shortages have been in recent years a critical problem in the world and are likely to be continued. A major part of consumed energy nowadays is used to thermally control building environment where solar radiation has a major contribution, specially in Iraq and other hot arid region where most of the day in the year are sunny. Baghdad, which is considered a typical place with this extreme climate, is chosen, in this study. This work deals with the possibility of the reducing energy consumption in building by blocking or eliminate the effect of direct solar radiation in summer season which the cooling is dominate in Iraq. It is especially important to minimize the effect of solar radiation incident upon the roof surface, which is focusing about it in this study. The roof surface most exposed to solar radiation and most of the solar gain absorbed by roof is transmitted down to the inside space. In this study built a system which spry water upon the external surface consist of net work piping system, control valves, spry nozzles, thermocouples sensor and digital temperature indicators. The study has been done in order to reduce the cooling load in living room. Reducing the heat transfer through the roof by using water spry roof system (WSRS) in Iraq's houses which reduced the heat transmission to the inside space about 96%. The result of this study shows good indication to use this method, to reduce the energy transmission. i./e. the energy transmission to inside living space through roof is about 4% only.(Author)

  3. Feed handling of lactating crossbred cows maintained in a semi-arid region during the hot season: physiological parameters, ingestive behavior and performance.

    Science.gov (United States)

    de Paula Xavier de Andrade, Rafael; de Andrade Ferreira, Marcelo; de Azevedo, Marcílio; da Silva, Emmanuelle Cordeiro; Urbano, Stela Antas; da Conceição, Maria Gabriela; de Lima Silva, Janaina

    2017-01-01

    The effects of time of feed delivery (14.00 hours; 14.00 and 20.00 hours; 16.00 and 18.00 hours) on the physiological parameters, ingestive behavior, nutrient intake and production of lactating cows maintained in a semi-arid region during the hot season were evaluated. Regardless of treatment, all animals received the first feeding supply at 06.00 hours. Eight cows with an average body weight of 600 kg, average milk yield of 20 kg/day and 80 days in milk were utilized. The rectal temperature, respiratory rate and sweating rate were not affected (P > 0.05), with average values of 38.5°C, 53.8 movements/min and 104 g/m 2 /h respectively. There was no effect (P > 0.05) on the eating time (314 min/day), ruminating time (564 min/day), drinking time (61 min/day) and idle time (502 min/day). Similarly, the intake of nutrients and performance of lactating cows were not affected (P > 0.05), with average dry matter intake of 19.8 kg/day, 4% fat-corrected milk of 20.6 kg/day and milk fat concentration of 4.03 g/100 g. Since the behavior and performance have not altered, any times of feed delivery evaluated could be used to crossbred Holstein × Zebu cows maintained on a feedlot in semi-arid regions during the hot season. © 2016 Japanese Society of Animal Science.

  4. Characterizing rainfall of hot arid region by using time-series modeling and sustainability approaches: a case study from Gujarat, India

    Science.gov (United States)

    Machiwal, Deepesh; Kumar, Sanjay; Dayal, Devi

    2016-05-01

    This study aimed at characterization of rainfall dynamics in a hot arid region of Gujarat, India by employing time-series modeling techniques and sustainability approach. Five characteristics, i.e., normality, stationarity, homogeneity, presence/absence of trend, and persistence of 34-year (1980-2013) period annual rainfall time series of ten stations were identified/detected by applying multiple parametric and non-parametric statistical tests. Furthermore, the study involves novelty of proposing sustainability concept for evaluating rainfall time series and demonstrated the concept, for the first time, by identifying the most sustainable rainfall series following reliability ( R y), resilience ( R e), and vulnerability ( V y) approach. Box-whisker plots, normal probability plots, and histograms indicated that the annual rainfall of Mandvi and Dayapar stations is relatively more positively skewed and non-normal compared with that of other stations, which is due to the presence of severe outlier and extreme. Results of Shapiro-Wilk test and Lilliefors test revealed that annual rainfall series of all stations significantly deviated from normal distribution. Two parametric t tests and the non-parametric Mann-Whitney test indicated significant non-stationarity in annual rainfall of Rapar station, where the rainfall was also found to be non-homogeneous based on the results of four parametric homogeneity tests. Four trend tests indicated significantly increasing rainfall trends at Rapar and Gandhidham stations. The autocorrelation analysis suggested the presence of persistence of statistically significant nature in rainfall series of Bhachau (3-year time lag), Mundra (1- and 9-year time lag), Nakhatrana (9-year time lag), and Rapar (3- and 4-year time lag). Results of sustainability approach indicated that annual rainfall of Mundra and Naliya stations ( R y = 0.50 and 0.44; R e = 0.47 and 0.47; V y = 0.49 and 0.46, respectively) are the most sustainable and dependable

  5. Designing of zero energy office buildings in hot arid climate

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Gwad, Mohamed

    2011-07-01

    The designing of office buildings by using large glass areas to have a transparent building is an attractive approach in the modern office building architecture. This attitude increases the energy demand for cooling specially in the hot arid region which has long sun duration time, while the use of small glazing areas increases the energy demand for lighting. The use of uncontrolled natural ventilation increases the rate of hot ambient air flow which increases the building energy demand for cooling. At the same time, the use of mechanical ventilation to control the air change rate may increase the energy demand for fans. Some ideas such as low energy design concept are introduced for improving the building energy performance and different rating systems have been developed such as LEED, BREEAM and DGNB for evaluating building energy performance system. One of the new ideas for decreasing the dependence on fossil fuels and improving the use of renewable energy is the net zero-energy building concept in which the building generates enough renewable energy on site to equal or exceed its annual energy use. This work depends on using the potentials of mixing different energy strategies such as hybrid ventilation strategy, passive night cooling, passive chilled ceiling side by side with the integrating of photovoltaic modules into the building facade to produce energy and enrich the architectural aesthetics and finally reaching the Net Zero Energy Building. There are different definitions for zero energy buildings, however in this work the use of building-integrated Photovoltaic (BIPV) to provide the building with its annual energy needs is adopted, in order to reach to a Grid-Connected Net-Zero Energy Office Building in the hot arid desert zone represented by Cairo, Egypt. (orig.)

  6. Greening reclamation of arid region

    Energy Technology Data Exchange (ETDEWEB)

    Kamichika, Makio [Tottori Univ. (Japan)

    1989-01-20

    Arid regions occupy a third of the whole land in the world, and desertification in the rimland makes a problem become more acute. It is also a problem that the large part of such areas is distributed in developing countries. Desertification is defined as a phenomenon, by which the ecological system is degenerated by the change of weather conditions and the pressure of human beings and livestock, and productivity of land is markedly deteriorated. In order to prevent desertification and to promote greening reclamation and agricultural development, it is necessary to analyze desertification mechanism in detail. Artificial factors are overpopulation, too much pasturage, and conversion of grassland into farmland. Natural environmental factors are weather conditions, water resources, soil conditions, etc. It is also important for greening reclamation and development of farm land to evaluate the amount of meteorological resources (such as water resources, energy resources, etc.) and to search for the possibility of their utilization. Because of major condition to grow plants is water environment, investigation and development of water resources are important. If a project ignores the cycle of the ecological system, it might be in danger of retrogradation toward desertification. 8 refs., 10 figs., 4 tabs.

  7. Is annual recharge coefficient a valid concept in arid and semi-arid regions?

    Directory of Open Access Journals (Sweden)

    Y. Cheng

    2017-10-01

    Full Text Available Deep soil recharge (DSR (at depth greater than 200 cm is an important part of water circulation in arid and semi-arid regions. Quantitative monitoring of DSR is of great importance to assess water resources and to study water balance in arid and semi-arid regions. This study used a typical bare land on the eastern margin of Mu Us Sandy Land in the Ordos Basin of China as an example to illustrate a new lysimeter method of measuring DSR to examine if the annual recharge coefficient is valid or not in the study site, where the annual recharge efficient is the ratio of annual DSR over annual total precipitation. Positioning monitoring was done on precipitation and DSR measurements underneath mobile sand dunes from 2013 to 2015 in the study area. Results showed that use of an annual recharge coefficient for estimating DSR in bare sand land in arid and semi-arid regions is questionable and could lead to considerable errors. It appeared that DSR in those regions was influenced by precipitation pattern and was closely correlated with spontaneous strong precipitation events (with precipitation greater than 10 mm other than the total precipitation. This study showed that as much as 42 % of precipitation in a single strong precipitation event can be transformed into DSR. During the observation period, the maximum annual DSR could make up 24.33 % of the annual precipitation. This study provided a reliable method of estimating DSR in sandy areas of arid and semi-arid regions, which is valuable for managing groundwater resources and ecological restoration in those regions. It also provided strong evidence that the annual recharge coefficient was invalid for calculating DSR in arid and semi-arid regions. This study shows that DSR is closely related to the strong precipitation events, rather than to the average annual precipitation, as well as the precipitation patterns.

  8. Evaluating rainwater harvesting systems in arid and semi-arid regions

    NARCIS (Netherlands)

    Ammar, Adham Ali

    2017-01-01

    Rainwater harvesting (RWH) is an ancient traditional technology practised in many parts of the world, especially in arid and semi-arid regions (ASARs). ASARs represent 40% of the earth’s land surface and are characterised by low average annual rainfall and uneven temporal and spatial

  9. HotRegion: a database of predicted hot spot clusters.

    Science.gov (United States)

    Cukuroglu, Engin; Gursoy, Attila; Keskin, Ozlem

    2012-01-01

    Hot spots are energetically important residues at protein interfaces and they are not randomly distributed across the interface but rather clustered. These clustered hot spots form hot regions. Hot regions are important for the stability of protein complexes, as well as providing specificity to binding sites. We propose a database called HotRegion, which provides the hot region information of the interfaces by using predicted hot spot residues, and structural properties of these interface residues such as pair potentials of interface residues, accessible surface area (ASA) and relative ASA values of interface residues of both monomer and complex forms of proteins. Also, the 3D visualization of the interface and interactions among hot spot residues are provided. HotRegion is accessible at http://prism.ccbb.ku.edu.tr/hotregion.

  10. Uses of tree legumes in semi-arid regions

    Energy Technology Data Exchange (ETDEWEB)

    Felker, P.

    1980-01-01

    Uses of tree legumes in semi-arid and arid regions are reviewed. This review is divided into sections according to the following general use categories: fuels; human food; livestock food; to increase yields of crops grown beneath their canopies;and control of desertification. (MHR)

  11. Evaporation as the transport mechanism of metals in arid regions

    KAUST Repository

    Lima, Ana T.; Safar, Zeinab; Loch, J.P. Gustav

    2014-01-01

    in soils. Due to the low rainfall and high evaporation rates in arid regions, groundwater quality is not threatened and all soil contamination issues tend to be overlooked. But if soil contamination happens, where do contaminants go? This study tests

  12. Isotope techniques in water resource investigations in arid and semi-arid regions

    International Nuclear Information System (INIS)

    2001-03-01

    The Co-ordinated Research Project (CRP) on the Use of Isotope Techniques in Water Resources Investigations in Arid and Semi-arid Regions was initiated with the aim od contributing to the assessment of groundwater resources in arid areas through the use of environmental isotope techniques, and thereby to help in better management of these valuable fresh groundwater resources. The main emphases identified were in three key areas: (i) the evaluation of water balance components such as recharge rate estimation and recharge and discharge cycles at different spatial scales, (ii) paleohydrology and hydroclimatic change and, (iii) anthropogenic impacts and the assessment of the vulnerability of arid zone ground waters to salinisation and pollution impacts. This publication presents individual projects carried out within the frameworks of the CRP. Each paper has been indexed separately

  13. Hazard Analysis of Arid and Semi-Arid (ASAL) Regions of Kenya ...

    African Journals Online (AJOL)

    Objectives: The overall objective of this study was to prioritize hazards in the ASAL region. ... Health, local Government, and Provincial Administration, Environment and NGO. ... and country level to inform interventions and other developmental activities. Women ... Keywords: hazard, natural disaster, disaster risk, arid, Kenya ...

  14. Evaporation as the transport mechanism of metals in arid regions

    NARCIS (Netherlands)

    Lima, A.T.; Safar, Z.; Loch, J.P.G.

    Soils of arid regions are exposed to drought and drastic temperature oscillations throughout the year. Transport mechanisms in these soils are therefore very different from the ones in temperate regions, where rain dictates the fate of most elements in soils. Due to the low rainfall and high

  15. Adaptation at Scale in Semi-Arid Regions | IDRC - International ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    People living in Africa and South Asia's semi-arid regions face challenges that hinder their economic growth and development. This project seeks to find proactive, longer-term approaches to climate change adaptation in these vulnerable regions, while helping locals manage existing risks. Short-term focus must shift. So far ...

  16. Evaporation as the transport mechanism of metals in arid regions

    KAUST Repository

    Lima, Ana T.

    2014-09-01

    Soils of arid regions are exposed to drought and drastic temperature oscillations throughout the year. Transport mechanisms in these soils are therefore very different from the ones in temperate regions, where rain dictates the fate of most elements in soils. Due to the low rainfall and high evaporation rates in arid regions, groundwater quality is not threatened and all soil contamination issues tend to be overlooked. But if soil contamination happens, where do contaminants go? This study tests the hypothesis of upward metal movement in soils when evaporation is the main transport mechanism. Laboratory evaporation tests were carried out with heavy metal spiked Saudi soil, using circulation of air as the driving force (Fig. 1). Main results show that loamy soil retains heavy metals quite well while evaporation drives heavy metals to the surface of a sandy soil. Evaporation transports heavy metals upward in sandy soils of arid regions, making them accumulate at the soil surface. Sand being the dominating type of soil in arid regions, soils can then be a potential source of contaminated aerosols and atmospheric pollution - a transboundary problem. Some other repercussions for this problem are foreseen, such as the public ingestion or inhalation of dust. © 2014 Elsevier Ltd.

  17. Salinization mechanisms in semi-arid regions

    International Nuclear Information System (INIS)

    Santiago, M.M.F.

    1984-01-01

    During a period of three years the basins of the Pereira de Miranda and Caxitore dams, located in the crystalline rock area of Ceara, Brazil, were studied in order to determine the mechanisms of salinization of their waters. Isotope methods ( 18 O/ 16 O) and hidrochemistry (determination of the of the maior ions) were applied to surface, underground and rain water in this study. An isotope model was designed and applied to the determination of evaporation and percolation of dams in semi-arid zones during the dry season. The results are compared to those from a conventional chemical model. As causes of salinization of the water in the dams, the contributions of the rain itself and the lixiviation of the soil are quantified. An interaction between the dams and the underground water is imperceptible. The salinization of the underground water is attributed to recharge of the aquifer with rain water from the surface runoff followed by evaporation of the water rising, due to capilarity, in a one-directional flow to the surface. (Author) [pt

  18. Simulation of water use and herbage growth in arid regions

    NARCIS (Netherlands)

    Keulen, van H.

    1975-01-01

    The and and semi-arid regions of the world, totalling about 30% of the land surface of the earth, are predominantly used for extensive grazing, as low and erratic rainfall presents too high a risk for arable farming. The population that can be sustained by the animal products -meat, milk or

  19. Analysis of Water Use and Water Scarcity in Arid and Semi-arid Regions

    Science.gov (United States)

    Samayoa, S. D.

    2017-12-01

    Analysis of Water Use and Water Scarcity in Arid and Semi-arid Regions Susana Samayoa , Muhammed A. G. Chowdhury, Tushar Sinha Department of Environmental Engineering, Texas A & M University - Kingsville Freshwater sustainability in arid and semi-arid regions is highly uncertain under increasing demands due to population growth and urban development as well as limited water supply. In particular, six largest cities by population among the top twenty U.S. cities are located in Texas (TX), which also experience high variability in water availability due to frequent droughts and floods. Similarly, several regions in Arizona (AZ) are rapidly growing (e.g. Phoenix and Tucson) despite receiving scanty rainfall. Thus, the goal of this study is to analyze water use and water scarcity in watersheds within TX and AZ between 1985 and 2010. The water use data from U.S. Geological Survey (USGS) is analyzed by Hydrological Unit Code (HUC) - 8 within TX and AZ. Total freshwater use by county during 1985 and 2010 were converted into water use by HUC-8 using geospatial analysis. Water availability will be estimated by using a large scale Variable Infiltration Capacity (VIC) hydrologic model. The VIC model will be calibrated and validated for multiple basins located in Texas and Arizona. The VIC model simulated total streamflow will be aggregated across the 1/8 degree grids that are within each HUC-8 to estimate water supply. The excess water for upstream HUC-8s (= local supply minus demands) will be routed, in addition to locally generated streamflow, to estimate water availability in downstream HUC-8s. Water Scarcity Index, defined as the ratio of total freshwater demand to supply, will be estimated during 1985 and 2010 to evaluate the effects of water availability and demands on scarcity. Finally, water scarcity and use will be analyzed by HUC-8s within TX and AZ. Such information could be useful in water resources management and planning. Keywords: Water scarcity, water use

  20. Assessment of stress due to hot ambience in donkeys from arid tracts in India

    Directory of Open Access Journals (Sweden)

    Kataria N.

    2010-11-01

    Full Text Available To assess the stress due to hot ambience in donkeys from arid tracts in Rajasthan state, India, serum prolactin and cortisol levels were determined by radioimmunoassay. The blood samples to harvest the serum were collected from the same animals during moderate (maximum temperature of 28 C - 29 C and hot (maximum temperature of 45 C- 46 C ambiences. During hot ambience the animals showed significantly (p0.05 higher levels of serum prolactin and cortisol when compared to the moderate ambience. The mean rise in prolactin was 4.42 times whereas cortisol levels were 4.22 times higher. Further a multiple fold rise in serum prolactin clearly suggested that it can also be used as an indicator of stress in donkeys along with the cortisol.

  1. The current bioenergy production potential of semi-arid and arid regions in sub-Saharan Africa

    NARCIS (Netherlands)

    Wicke, B.; Smeets, E.M.W.; Watson, H.; Faaij, A.P.C.

    2011-01-01

    This article assesses the current technical and economic potential of three bioenergy production systems (cassava ethanol, jatropha oil and fuelwood) in semi-arid and arid regions of eight sub-Saharan African countries. The results indicate that the availability of land for energy production ranges

  2. Determine the optimum spectral reflectance of juniper and pistachio in arid and semi-arid region

    Science.gov (United States)

    Fadaei, Hadi; Suzuki, Rikie

    2012-11-01

    Arid and semi-arid areas of northeast Iran cover about 3.4 million ha are populated by two main tree species, the broadleaf Pistacia vera. L (pistachio) and the conifer Juniperus excelsa ssp. polycarpos (Persian juniper). Natural stands of pistachio in Iran are not only environmentally important but genetically essential as seed sources for pistachio production in orchards. In this study, we estimated the optimum spectral reflectance of juniper forests and natural pistachio stands using remote sensing to help in the sustainable management and production of pistachio in Iran. In this research spectral reflectance are able to specify of multispectral from Advanced Land Observing Satellite (ALOS) that provided by JAXA. These data included PRISM is a panchromatic radiometer with a 2.5 m spatial resolution at nadir, has one band with a wavelength of 0.52-0.77 μm and AVNIR-2 is a visible and near infrared radiometer for observing land and coastal zones with a 10 m spatial resolution at nadir, has four multispectral bands: blue (0.42-0.50 μm), green (0.52-0.60 μm), red (0.61-0.69 μm), and near infrared (0.76-0.89 μm). Total ratio vegetation index (TRVI) of optimum spectral reflectance of juniper and pistachio have been evaluated. The result of TRVI for Pistachio and juniper were (R2= 0.71 and 0.55). I hope this research can provide decision of managers to helping sustainable management for arid and semi-arid regions in Iran.

  3. Seasonal behavioral responses of an arid-zone passerine in a hot environment.

    Science.gov (United States)

    Pattinson, Nicholas B; Smit, Ben

    2017-10-01

    Many arid-zone animals have to forage under extremely hot conditions to maintain water and energy balance. The effect of high air temperatures (T air ) on the behavioral patterns of small endothermic animals-characterized by their high energy and water demands-will provide a valuable framework for understanding species vulnerability to climate warming. We determined the seasonal behavioral responses to changes in T air in a~10-g arid-zone passerine, the rufous-eared warbler (Malcorus pectoralis), in the Karoo semi-desert, South Africa. Rufous-eared warblers showed significant temperature-dependence in their behavior in summer, but not in winter. During summer, the warblers frequently experienced T air exceeding 40°C in the shade. For all observations 36°C, the warblers showed reductions in preening (40% decrease), foraging effort (56% decrease), and foraging success (15% decrease), as well as a significant increase in time spent engaged in evaporative cooling behavior. Moreover, as T air increased the warblers shifted increasingly off the ground and out of the full sun, into microsites in the shade (131% increase) and in shrubs (23% increase). In this regard, behavior varied seasonally, with the time spent in the shade 23% higher, and foraging effort 28% higher, in summer compared to winter across a range of moderate T air (15-30°C). Our findings emphasize the link between behavior and temperature in small birds inhabiting hot, arid environments, as well as the importance of understanding these responses for predicting biologically meaningful responses (and hence, vulnerability) of arid-zone avian communities to climactic shifts. Copyright © 2017 Elsevier Inc. All rights reserved.

  4. Effects of environmental conditions on soil salinity and arid region in Tunisia

    International Nuclear Information System (INIS)

    Ben Ahmed, C.; Ben Rouina, B.; Boukhris, M.

    2009-01-01

    The shortage of water resources of good water quality is becoming an issue in the arid and semi arid regions. for this reason, the use of water resources of marginal quality such as treated wastewater and saline groundwater has become and important consideration, particularly in arid region in Tunisia, where large quantities of saline water are used for irrigation. (Author)

  5. Modeling of hydrological processes in arid agricultural regions

    Directory of Open Access Journals (Sweden)

    Jiang LI,Xiaomin MAO,Shaozhong KANG,David A. BARRY

    2015-12-01

    Full Text Available Understanding of hydrological processes, including consideration of interactions between vegetation growth and water transfer in the root zone, underpins efficient use of water resources in arid-zone agriculture. Water transfers take place in the soil-plant-atmosphere continuum, and include groundwater dynamics, unsaturated zone flow, evaporation/transpiration from vegetated/bare soil and surface water, agricultural canal/surface water flow and seepage, and well pumping. Models can be categorized into three classes: (1 regional distributed hydrological models with various land uses, (2 groundwater-soil-plant-atmosphere continuum models that neglect lateral water fluxes, and (3 coupled models with groundwater flow and unsaturated zone water dynamics. This review highlights, in addition, future research challenges in modeling arid-zone agricultural systems, e.g., to effectively assimilate data from remote sensing, and to fully reflect climate change effects at various model scales.

  6. Crop production and economic loss due to wind erosion in hot arid ecosystem of India

    Science.gov (United States)

    Santra, Priyabrata; Moharana, P. C.; Kumar, Mahesh; Soni, M. L.; Pandey, C. B.; Chaudhari, S. K.; Sikka, A. K.

    2017-10-01

    Wind erosion is a severe land degradation process in hot arid western India and affects the agricultural production system. It affects crop yield directly by damaging the crops through abrasion, burial, dust deposition etc. and indirectly by reducing soil fertility. In this study, an attempt was made to quantify the indirect impact of wind erosion process on crop production loss and associated economic loss in hot arid ecosystem of India. It has been observed that soil loss due to wind erosion varies from minimum 1.3 t ha-1 to maximum 83.3 t ha-1 as per the severity. Yield loss due to wind erosion was found maximum for groundnut (Arachis hypogea) (5-331 kg ha-1 yr-1), whereas minimum for moth bean (Vigna aconitifolia) (1-93 kg ha-1 yr-1). For pearl millet (Pennisetum glaucum), which covers a major portion of arable lands in western Rajasthan, the yield loss was found 3-195 kg ha-1 yr-1. Economic loss was found higher for groundnut and clusterbean (Cyamopsis tetragonoloba) than rest crops, which are about

  7. Ecotoxicology of organisms adapted to life in temporary freshwater ponds in arid and semi-arid regions.

    Science.gov (United States)

    Lahr, J

    1997-01-01

    Hot arid and semi-arid zones are characterized by an abundance of temporary ponds. Most of these depend on rain for their existence. These habitats are distinguished by fluctuating and unpredictable changes in their hydrological regime and of physical and chemical conditions.They contain a uniquely-adapted fauna that copes in different ways with changing and often extreme temperatures, oxygen levels, pH, salinity and turbidity. A classification is presented of the most distinctive adaptations,the various tactics that organisms apply to survive dry periods. The main strategies are dormancy (escape in time) and dispersal (escape in space). These adaptations may affect the impact of toxicants on individuals, populations and communities of temporary ponds. The physiological adaptations of species found in temporary ponds are likely to alter the sensitivity to pollutants of characteristic species. Results from laboratory experiments,for example, suggest that fairy shrimp (Branchiopoda, Anostraca) may react differently to heavy metals and pesticides as the standard test species Daphnia. Life history strategies influence recovery rates of populations after exposure to acutely toxic substances such as pesticides. It is also suggested that slow growth and decreased reproductive capacity of organisms caused by toxicants may, in ephemeral ponds, result in the failure of annual recruitment. Whether assemblages of organisms in temporary ponds are generally more vulnerable or more resilient than those in permanent waters or temperate regions could not be determined conclusively with the limited data available. Ecological concepts for studying the habitat and the development of risk assessment methods for temporary ponds are briefly discussed.

  8. Excessive reliance on afforestation in China's arid and semi-arid regions: Lessons in ecological restoration

    Science.gov (United States)

    Cao, Shixiong; Chen, Li; Shankman, David; Wang, Chunmei; Wang, Xiongbin; Zhang, Hong

    2011-02-01

    Afforestation is a primary tool for controlling desertification and soil erosion in China. Large-scale afforestation, however, has complex and poorly understood consequences for the structure and composition of future ecosystems. Here, we discuss the potential links between China's historical large-scale afforestation practices and the program's effects on environmental restoration in arid and semi-arid regions in northern China based on a review of data from published papers, and offer recommendations to overcome the shortcomings of current environmental policy. Although afforestation is potentially an important approach for environmental restoration, current Chinese policy has not been tailored to local environmental conditions, leading to the use of inappropriate species and an overemphasis on tree and shrub planting, thereby compromising the ability to achieve environmental policy goals. China's huge investment to increase forest cover seems likely to exacerbate environmental degradation in environmentally fragile areas because it has ignored climate, pedological, hydrological, and landscape factors that would make a site unsuitable for afforestation. This has, in many cases, led to the deterioration of soil ecosystems and decreased vegetation cover, and has exacerbated water shortages. Large-scale and long-term research is urgently needed to provide information that supports a more effective and flexible environmental restoration policy.

  9. The simulation of naturally ventilated residential buildings in semi-arid regions

    Energy Technology Data Exchange (ETDEWEB)

    Ghiabaklou, Z.; Ballinger, J.A.; Prasad, D.K. [New South Wales Univ., Kensington, NSW (Australia). Solar Architecture Research Unit

    1995-12-31

    The most important consideration in hot arid and semi-arid zones is to reduce the internal day temperature and to maintain the interior spaces of buildings in a comfortable condition. An important contributor to errors in the thermal analysis of naturally ventilated buildings is inaccurate airflow predictions. These predictions are important for designers in regions where most buildings are naturally ventilated. Passive cooling by day and night natural ventilation in a single story residential building in Wagga Wagga, a semi-arid location in New South Wales has been compared and analyzed theoretically. A modified version of the computer simulation program CHEETAH, has been used to consider a building with continuous natural ventilation to simulate indoor air temperature. The aim of the study was to investigate the thermal behaviour of the building with continuous ventilation (24 hour/day) and the same building with only night time ventilation. Using night time ventilation in high mass buildings in such a climate, leads to a considerable decrease in room air temperature. Simulation results showed that increasing the effective area of windows is effective only when the wind blows. Using a steady averaged air change per hour can also cause a reduction in room air temperatures which results in different temperatures than the actual air changes per hour. (author). 3 figs., 4 refs.

  10. Hourly Wind Speed Interval Prediction in Arid Regions

    Science.gov (United States)

    Chaouch, M.; Ouarda, T.

    2013-12-01

    The long and extended warm and dry summers, the low rate of rain and humidity are the main factors that explain the increase of electricity consumption in hot arid regions. In such regions, the ventilating and air-conditioning installations, that are typically the most energy-intensive among energy consumption activities, are essential for securing healthy, safe and suitable indoor thermal conditions for building occupants and stored materials. The use of renewable energy resources such as solar and wind represents one of the most relevant solutions to overcome the increase of the electricity demand challenge. In the recent years, wind energy is gaining more importance among the researchers worldwide. Wind energy is intermittent in nature and hence the power system scheduling and dynamic control of wind turbine requires an estimate of wind energy. Accurate forecast of wind speed is a challenging task for the wind energy research field. In fact, due to the large variability of wind speed caused by the unpredictable and dynamic nature of the earth's atmosphere, there are many fluctuations in wind power production. This inherent variability of wind speed is the main cause of the uncertainty observed in wind power generation. Furthermore, producing wind power forecasts might be obtained indirectly by modeling the wind speed series and then transforming the forecasts through a power curve. Wind speed forecasting techniques have received substantial attention recently and several models have been developed. Basically two main approaches have been proposed in the literature: (1) physical models such as Numerical Weather Forecast and (2) statistical models such as Autoregressive integrated moving average (ARIMA) models, Neural Networks. While the initial focus in the literature has been on point forecasts, the need to quantify forecast uncertainty and communicate the risk of extreme ramp events has led to an interest in producing probabilistic forecasts. In short term

  11. Uranium isotopes in carbonate aquifers of arid region setting

    International Nuclear Information System (INIS)

    Alshamsi, D.M.; Murad, A.A.

    2013-01-01

    Groundwater in arid and semiarid regions is vital resource for many uses and therefore information about concentrations of uranium isotopes among other chemical parameters are necessary. In the study presented here, distribution of 238 U and 235 U in groundwater of four selected locations in the southern Arabian peninsula, namely at two locations within the United Arab Emirates (UAE) and two locations in Oman are discussed. The analyses of the uranium isotopes were performed using ICP-MS and the results indicated a range of concentrations for 235 U and 238 U at 3-39 ng L -1 (average: 18 ng L -1 ) and 429-5,293 ng L -1 (average: 2,508 ng L -1 ) respectively. These uranium concentrations are below the higher permissible WHO limit for drinking water and also comparable to averages found in groundwater from similar aquifers in Florida and Tunisia. Negative correlation between rainfall and uranium concentrations suggests that in lithologically comparable aquifers, climate may influence the concentration of uranium in subtropical to arid regions. (author)

  12. ESTIMATION OF EXTRACELLULAR LIPOLYTIC ENZYME ACTIVITY BY THERMOPHILIC BACILLUS SP. ISOLATED FROM ARID AND SEMI-ARID REGION OF RAJASTHAN, INDIA

    Directory of Open Access Journals (Sweden)

    Deeksha Gaur

    2012-10-01

    Full Text Available Thermophilic organisms can be defined as, micro-organisms which are adapted to survive at high temperatures. The enzymes secreted by thermophilic bacteria are capable of catalyzing biochemical reactions at high temperatures. Thermophilic bacteria are able to produce thermostable lipolytic enzymes (capable of degradation of lipid at temperatures higher than mesophilic bacteria. Therefore, the isolation of thermophilic bacteria from natural sources and their identification are quite beneficial in terms of discovering thermostable lipase enzymes. Due to great temperature fluctuation in hot arid and semi-arid region of Rajasthan, this area could serve as a good source for new thermophilic lipase producing bacteria with novel industrially important properties. The main objective of this research is the isolation and estimation of industrially important thermophilic lipase enzyme produced by thermophilic bacteria, isolated from arid and semi-arid region of Rajasthan. For this research purpose soil samples were collected from Churu, Sikar and Jhunjunu regions of Rajasthan. Total 16 bacterial strains were isolated and among only 2 thermostable lipolytic enzyme producing bacteria were charcterized. The thermostable lipolytic enzyme was estimated by qualitative and quantitative experiments. The isolates were identified as Bacillus sp. by microscopic, biochemical and molecular characterization. The optimum enzyme activity was observed at pH 8, temperature 60°C and 6% salt concentrations at 24 hrs time duration. Lipolytic enzyme find useful in a variety of biotechnological fields such as food and dairy (cheese ripening, flavour development, detergent, pharmaceutical (naproxen, ibuprofen, agrochemical (insecticide, pesticide and oleochemical (fat and oil hydrolysis, biosurfactant synthesis industries. Lipolytic enzyme can be further used in many newer areas where they can serve as potential biocatalysts.

  13. Assessment of Spatio-temporal Barren-lands Expansion and Agricultural Adaptation due to Climate Change and Anthropogenic Activity: A Geospatial Approach in Hot Semi-arid Region of Maharashtra State, India

    Science.gov (United States)

    Roy, A.; Inamdar, A. B.

    2017-12-01

    Major parts of Upper Godavari River Basin are intensely drought prone and climate vulnerable in Maharashtra State, India. The economy of the state depends on the agronomic productivity of this region. So, it is necessary to monitor and regulate the effects of climate change and anthropogenic activity on agricultural land in that region. This study investigates and maps the barren-lands and alteration of agricultural lands, their decadal deviations with the multi-temporal LANDSAT satellite images; and finally quantifies the agricultural adaptations. This work involves the utilization of remote sensing and GIS tools and modeling. First, climatic trend analysis is carried out with dataset obtained from India Meteorological Department. Then, multi-temporal LANDSAT images are classified (Level I, hybrid classification technique are followed) to determine the decadal Land Use Land Cover (LULC) changes and correlated with the agricultural water demand. Finally, various LANDSAT band analysis is conducted to determine irrigated and non-irrigated cropping area estimation and identifying the agricultural adaptations. The analysis of LANDSAT images shows that barren-lands are most increased class during the study period. The overall spatial extent of barren-lands are increased drastically during the study period. The geospatial study (class-to-class conversion study) shows that, most of the conversion of the barren-lands are from the agricultural land and reserve or open forests. The barren-lands are constantly increasing and the agricultural land is linearly decreasing. Hence, there is an inverse correlation between barren-lands and agricultural land. Moreover, there is a shift to non-irrigated and less water demanding crops, from more water demanding crops, which is a noticeable adaptation. The surface-water availability is highly dependent on rainfall and/or climatic conditions. It is changing either way in a random fashion based upon the quantity of rainfall occurred in

  14. Pipeline monitoring with interferometry in non-arid regions

    Energy Technology Data Exchange (ETDEWEB)

    McCardle, Adrian; Rabus, Bernhard; Ghuman, Parwant [MacDonald Dettwiler, Richmond, BC (Canada); Freymueller, Jeff T. [University of Alaska, Fairbanks (United States)

    2005-07-01

    Interferometry has become a proven technique for accurately measuring ground movements caused by subsidence, landslides, earthquakes and volcanoes. Using space borne sensors such as the ERS, ENVISAT and RADARSAT satellites, ground deformation can be monitored on a millimeter level. Traditionally interferometry has been limited to arid areas however new technology has allowed for successful monitoring in vegetated regions and areas of changing land-cover. Analysis of ground movement of the Trans-Alaskan pipeline demonstrates how these techniques can offer pipeline engineers a new tool for observing potential dangers to pipeline integrity. Results from Interferometric Point Target Analysis were compared with GPS measurements and speckle tracking interferometry was demonstrated to measure a major earthquake. (author)

  15. Mapping of Temporal Surface-water Resources Availability and Agricultural Adaptability due to Climate Change and Anthropogenic Activity in a Hot Semi-arid Region of Maharashtra State, India

    Science.gov (United States)

    Roy, A.; Inamdar, A. B.

    2016-12-01

    Major part of Godavari River Basin is intensely drought prone and climate vulnerable in the Western Maharashtra State, India. The economy of the state depends on the agronomic productivity of this region. So, it is necessary to regulate the effects of existing and upcoming hydro-meteorological advances in various strata. This study investigates and maps the surface water resources availability and vegetation, their decadal deviations with multi-temporal LANDSAT images; and finally quantifies the agricultural adaptations. This work involves the utilization of Remote Sensing and GIS with Hydrological modeling. First, climatic trend analysis is carried out with NCEP dataset. Then, multi-temporal LANDSAT images are classified to determine the decadal LULC changes and correlated to the community level hydrological demand. Finally, NDVI, NDWI and SWAT model analysis are accomplished to determine irrigated and non-irrigated cropping area for identifying the agricultural adaptations. The analysis shows that the mean value of annual and monsoon rainfall is significantly decreasing, whereas the mean value of annual and summer temperature is increasing significantly and the winter temperature is decreasing. The analysis of LANDSAT images shows that the surface water availability is highly dependent on climatic conditions. Barren-lands are most dynamic during the study period followed by, vegetation, and water bodies. The spatial extent of barren-lands is increased drastically during the climate vulnerable years replacing the vegetation and surface water bodies. Hence, the barren lands are constantly increasing and the vegetation cover is linearly decreasing, whereas the water extent is changing either way in a random fashion. There appears a positive correlation between surface water and vegetation occurrence; as they are fluctuating in a similar fashion in all the years. The vegetation cover is densely replenished around the dams and natural water bodies which serve as the

  16. A Tool for the Evaluation of Irrigation Water Quality in the Arid and Semi-Arid Regions

    Directory of Open Access Journals (Sweden)

    Lucia Bortolini

    2018-02-01

    Full Text Available In the Mediterranean arid and semi-arid regions, large amounts of low quality waters could be used for crop irrigation, but the adoption of articulated classifications with too rigid quality limits can often reduce the recoverable quantities of water and make the monitoring of water quality too much expensive. Therefore, an evaluation of irrigation water quality based on only a few crucial parameters, which consider the crop species to be irrigated and the type of irrigation system and management adopted, can be an easy and flexible method for maximizing the reuse of wastewater and low-quality water for agricultural purposes. In this view, an irrigation water quality tool (IWQT was developed to support farmers of arid and semi-arid regions on evaluating the use of low quality water for crop irrigation. The most significant and cheapest parameters of irrigation water quality were identified and clustered in three quality classes according to their effects on crop yield and soil fertility (agronomic quality indicators, human health (hygiene and health quality indicators, and irrigation systems (management quality indicators. According to IWQT parameters, a tool reporting a series of recommendations, including water treatment types, was implemented to guide farmers on the use of low quality irrigation water.

  17. Voluntary dehydration among elementary school children residing in a hot arid environment.

    Science.gov (United States)

    Bar-David, Y; Urkin, J; Landau, D; Bar-David, Z; Pilpel, D

    2009-10-01

    Voluntary dehydration is a condition where humans do not drink appropriately in the presence of an adequate fluid supply. This may adversely affect their physical and intellectual performance. The present study aimed to describe the prevalence of voluntary dehydration among elementary school children of different ethnicities and countries of birth. Four hundred and twenty-nine elementary school children, aged 8-10 years, from four subpopulations (Israeli-born Jewish and Bedouin-Arab children, and immigrant children who recently arrived to Israel from Eastern Europe and from Ethiopia) were studied. The level of dehydration was determined by noontime urine osmolality, from samples taken over 1 week in mid-summer. Urine osmolality dehydrated group was that of Israeli-born Jewish children, whereas the Bedouin-Arab children were the least dehydrated. A high proportion of children who reside in a hot and arid environment were found to be in a state of moderate to severe dehydration. Bedouin ethnicity was associated with better hydration, whereas Israeli-born Jews were most severely dehydrated. Educational intervention programmes promoting water intake should start in early childhood and continue throughout life.

  18. Managing soil moisture on waste burial sites in arid regions

    International Nuclear Information System (INIS)

    Anderson, J.E.; Ratzlaff, T.D.; Nowak, R.S.; Markham, O.D.

    1993-01-01

    In semiarid regions, where potential evapotranspiration greatly exceeds precipitation, it is theoretically possible to preclude water form reaching interred wastes by (i) providing a sufficient cap of soil to store precipitation that falls while plants are dormant and (ii) establishing sufficient plant cover to deplete soil moisture during the growing season, thereby emptying the water storage reservoir of the soil. Here the authors discuss the theory and rationale for such an approach and then present the results of a field study to test its efficacy at the Idaho National Engineering Laboratory (INEL). They examined the capacity of four species of perennial plants to deplete soil moisture on simulated waste trenches and determined the effective water storage capacity of the soil. Those data enabled them to estimate the minimum depth of fill soil required to prevent deep drainage. Any of the species studied can use all of the plant-available soil water, even during a very wet growing season. The water storage capacity of the soil studied is 17% by volume, so a trench cap of 1.6 m of soil should be adequate to store precipitation received at the INEL while plants are dormant. They recommend a fill soil depth of 2 m to provide a margin of safety in case water accumulates in local areas as a result of heavy snow accumulation, subsidence, or runoff. Fill soil requirements and choice of plant species will vary, but the concepts and general approach are applicable to other shallow land burial sites in arid or semiarid regions. 23 refs., 5 figs

  19. Observational characteristics of cloud radiative effects over three arid regions in the Northern Hemisphere

    Science.gov (United States)

    Li, Jiandong; Wang, Tianhe; Habib, Ammara

    2017-08-01

    Cloud-radiation processes play an important role in regional energy budgets and surface temperature changes over arid regions. Cloud radiative effects (CREs) are used to quantitatively measure the aforementioned climatic role. This study investigates the characteristics of CREs and their temporal variations over three arid regions in central Asia (CA), East Asia (EA), and North America (NA), based on recent satellite datasets. Our results show that the annual mean shortwave (SW) and net CREs (SWCRE and NCRE) over the three arid regions are weaker than those in the same latitudinal zone of the Northern Hemisphere. In most cold months (November-March), the longwave (LW) CRE is stronger than the SWCRE over the three arid regions, leading to a positive NCRE and radiative warming in the regional atmosphere-land surface system. The cold-season mean NCRE at the top of the atmosphere (TOA) averaged over EA is 4.1 W m-2, with a positive NCRE from November to March, and the intensity and duration of the positive NCRE is larger than that over CA and NA. The CREs over the arid regions of EA exhibit remarkable annual cycles due to the influence of the monsoon in the south. The TOA LWCRE over arid regions is closely related to the high-cloud fraction, and the SWCRE relates well to the total cloud fraction. In addition, the relationship between the SWCRE and the low-cloud fraction is good over NA because of the considerable occurrence of low cloud. Further results show that the interannual variation of TOA CREs is small over the arid regions of CA and EA, but their surface LWCREs show certain decreasing trends that correspond well to their decreasing total cloud fraction. It is suggested that combined studies of more observational cloud properties and meteorological elements are needed for indepth understanding of cloud-radiation processes over arid regions of the Northern Hemisphere.

  20. Changes in precipitation recycling over arid regions in the Northern Hemisphere

    Science.gov (United States)

    Li, Ruolin; Wang, Chenghai; Wu, Di

    2018-01-01

    Changes of precipitation recycling (PR) in Northern Hemisphere from 1981 to 2010 are investigated using a water recycling model. The temporal and spatial characteristics of recycling in arid regions are analyzed. The results show that the regional precipitation recycling ratio (PRR) in arid regions is larger than in wet regions. PRR in arid regions has obvious seasonal variation, ranging from more than 25 % to less than 1 %. Furthermore, in arid regions, PRR is significantly negatively correlated with precipitation (correlation coefficient r = -0.5, exceeding the 99 % significance level). Moreover, the trend of PRR is related to changes in precipitation in two ways. PRR decreases with increasing precipitation in North Africa, which implies that less locally evaporated vapor converts into actual precipitation. However, in Asian arid regions, the PRR increases as precipitation reduces, which implies that more locally evaporated vapor converts into rainfall. Further, as PRR mainly depends on evapotranspiration, the PRR trend in Asian arid regions develops as temperature increases and more evaporated vapor enters the atmosphere to offset the reduced rainfall.

  1. Two thousand wind pumps in the arid region of Brazil

    International Nuclear Information System (INIS)

    Feitosa, E.A.N.; Sampaio, G.M.P.

    1991-01-01

    The North-East part of Brazil is an arid region where water pumping is of vital importance. The main strategy of the Wind Energy Group (Eolica) at the University of Pernambuco is to act as a 'catalyst' between the Brazilian government and the companies involved in wind energy. The company CONESP is a drilling company that is also responsible for choosing the appropriate pumping system and providing maintenance. CONESP already has drilled about 6,000 wells and installed 2,000 conventional windmills with piston pumps. Most of the wells have a very low capacity; thus wind pumps, having a relatively low water pumping capacity, are a suitable solution. However, one of the problems with the installed conventional wind pumps is that the drilled tube wells are not perfectly vertical, resulting in wear of the pump rod. Besides, the maintenance or replacement of the piston pump is time consuming and consequently costly. To reduce operation and maintenance costs, windmills coupled to pneumatic pumps have been developed. Examples are given of air-lift pumps and barc pumps, both using commercially available compressors. The main advantage is that there are no moving parts situated below ground level. Moreover, the windmill does not necessarily have to be placed above the well. Well and windmill can be situated up to 100 metres from each other. The starting torque of this system is also lower than the conventional wind pump. It is concluded that windmills with pneumatic pumps have a relatively low efficiency and higher investment costs compared with windmills coupled to piston pumps. However, CONESP's effort is to optimize the total performance of the pumping system. Due to the lower maintenance costs, pneumatic pumps seem to be a viable alternative to piston pumps. 7 figs., 3 refs

  2. Karst characterization in a semi-arid region using gravity, seismic, and resistivity geophysical techniques.

    Energy Technology Data Exchange (ETDEWEB)

    Barnhart, Kevin Scott

    2013-10-01

    We proposed to customize emerging in situ geophysical monitoring technology to generate time-series data during sporadic rain events in a semi-arid region. Electrodes were to be connected to wireless \

  3. Deep Soil Recharge in Arid and Semi-Arid Regions: New Evidences in MU-US Sandy Land of China

    Science.gov (United States)

    Cheng, Y.; Yang, W.; Zhan, H.

    2017-12-01

    Precipitation induced recharge is an important source of groundwater budget but it is very difficult to quantify in arid and semiarid regions. In this study, a newly invented lysimeter was used to monitor deep soil recharge (DSR) under 200 cm depth in MU-US sandy land in western China under three kinds of landforms (mobile dune, semi-fixed dune, and fixed dune). We found that the annual DSRs in such three different kinds of landforms varied significantly. Specifically, the annual DSRs were 224.1 mm (50.5% of the annual precipitation), 71.1 mm (50.5% of the annual precipitation), and 1.3 mm (0.3% of the annual precipitation) in mobile dune, semi-fixed dune, and fixed dune, respectively. We also found that vegetation coverage and precipitation pattern significantly affected DSR. A 24-hr precipitation event with the precipitation amount greater than 8 mm was able to infiltrate soil deeper than 200 cm and contributed to ground water recharge directly. Vegetation was a dominant factor influencing infiltration in the fixed sand dune. Our research revealed that precipitation induced DSR in arid and semi-arid regions was a complex process that required long-term monitoring and innovative system analysis of interrelated factors such as precipitation strength and pattern, meteorological parameters, and dynamic soil moisture. Key words: Precipitation pattern, sand dune groundwater, deep soil recharge, infiltration.

  4. Plan and Some Results of "Advanced Study on Precipitation Enhancement in Arid and Semi-Arid Regions"

    Science.gov (United States)

    Murakami, M.

    2016-12-01

    There are several technologies to secure water resources, including the desalination of seawater, recycling of industrial water and reuse of wastewater. However precipitation enhancement is the only way we can create a large amount of water for industrial use, for example, water for irrigation, provided we find clouds suitable for cloud seeding and apply appropriate and effective methods to increase precipitation. Therefore, rain enhancement research is critical in the quest for new water security options and innovative solutions in the UAE and other arid and semi-arid regions. The main objective of our project is to better evaluate, and ultimately improve, the effectiveness of rain enhancement in the UAE and other arid and semi-arid regions using hygroscopic and glaciogenic seeding techniques. One of the major questions regarding rain enhancement today is the effectiveness of hygroscopic seeding for warm and supercooled convective clouds. Our research will investigate the microphysical processes in seeded and unseeded clouds using a combination of laboratory experiments, numerical simulations and in-situ aircraft measurements in order to decipher the mechanism responsible for precipitation augmentation due to hygroscopic seeding. In our research, major elements of cloud seeding, e.g., assessment of seedability, development of optimal seeding methods and evaluation of seeding effects, will be investigated in the most efficient and realistic way, within three years, using mainly the numerical models with the sophisticated seeding scheme, which is developed on a basis of laboratory experiments and then validated against in-situ and remote sensing observations. In addition to the research plan, the outcomes of the research projects, which will be made available to the public at the end of the project and benefit the broader society, is discussed.

  5. THE SURFACE WATER STORAGE PROBLEM IN ARID REGIONS:

    African Journals Online (AJOL)

    H. Benfetta

    2017-09-01

    Sep 1, 2017 ... This dam is located in an arid zone where water resources are becoming increasingly scarce. It is situated 5 km ... Leakage leads to considerable losses of valuable, scarce water. ...... Detection of water leaks in the restraints ...

  6. Tropical Warm Semi-Arid Regions Expanding Over Temperate Latitudes In The Projected 21st Century

    Science.gov (United States)

    Rajaud, A.; de Noblet, N. I.

    2015-12-01

    Two billion people today live in drylands, where extreme climatic conditions prevail, and natural resources are limited. Drylands are expected to expand under several scenarios of climatic change. However, relevant adaptation strategies need to account for the aridity level: it conditions the equilibrium tree-cover density, ranging from deserts (hyper-arid) to dense savannas (sub-humid). Here we focus on the evolution of climatically defined warm semi-arid areas, where low-tree density covers can be maintained. We study the global repartition of these regions in the future and the bioclimatic shifts involved. We adopted a bioclimatological approach based on the Köppen climate classification. The warm semi-arid class is characterized by mean annual temperatures over 18°C and a rainfall-limitation criterion. A multi-model ensemble of CMIP5 projections for three representative concentration pathways was selected to analyze future conditions. The classification was first applied to the start, middle and end of the 20th and 21st centuries, in order to localize past and future warm semi-arid regions. Then, time-series for the classification were built to characterize trends and variability in the evolution of those regions. According to the CRU datasets, global expansion of the warm semi-arid area has already started (~+13%), following the global warming trend since the 1900s. This will continue according to all projections, most significantly so outside the tropical belt. Under the "business as usual" scenario, the global warm semi-arid area will increase by 30% and expand 12° poleward in the Northern Hemisphere, according to the multi-model mean. Drying drives the conversion from equatorial sub-humid conditions. Beyond 30° of latitude, cold semi-arid conditions become warm semi-arid through warming, and temperate conditions through combined warming and drying processes. Those various transitions may have drastic but also very distinct ecological and sociological

  7. Plant Communities Suitable for Green Roofs in Arid Regions

    Directory of Open Access Journals (Sweden)

    Rachel Gioannini

    2018-05-01

    , and root-to-shoot dry weight ratio (0.45 than native Euphorbia. At the end of year 2, the relative growth rate (RGR of native Euphorbia of 0.15 g·g−1·d−1 was greater than that of Sedum. While the native succulent had a smaller root biomass, its greater RWC and RGR would indicate it had better plant water status and grew faster than the non-native. The lack of differences in plant performance regardless of assignment to monoculture or community would imply that communities and monocultures are equally suitable for arid region green roofs.

  8. Global synthesis of groundwater recharge in semiarid and arid regions

    Science.gov (United States)

    Scanlon, Bridget R.; Keese, K.E.; Flint, A.L.; Flint, L.E.; Gaye, C.B.; Edmunds, W.M.; Simmers, I.

    2006-01-01

    Global synthesis of the findings from ∼140 recharge study areas in semiarid and arid regions provides important information on recharge rates, controls, and processes, which are critical for sustainable water development. Water resource evaluation, dryland salinity assessment (Australia), and radioactive waste disposal (US) are among the primary goals of many of these recharge studies. The chloride mass balance (CMB) technique is widely used to estimate recharge. Average recharge rates estimated over large areas (40–374 000 km2) range from 0·2 to 35 mm year−1, representing 0·1–5% of long-term average annual precipitation. Extreme local variability in recharge, with rates up to ∼720 m year−1, results from focussed recharge beneath ephemeral streams and lakes and preferential flow mostly in fractured systems. System response to climate variability and land use/land cover (LU/LC) changes is archived in unsaturated zone tracer profiles and in groundwater level fluctuations. Inter-annual climate variability related to El Niño Southern Oscillation (ENSO) results in up to three times higher recharge in regions within the SW US during periods of frequent El Niños (1977–1998) relative to periods dominated by La Niñas (1941–1957). Enhanced recharge related to ENSO is also documented in Argentina. Climate variability at decadal to century scales recorded in chloride profiles in Africa results in recharge rates of 30 mm year−1 during the Sahel drought (1970–1986) to 150 mm year−1 during non-drought periods. Variations in climate at millennial scales in the SW US changed systems from recharge during the Pleistocene glacial period (≥10 000 years ago) to discharge during the Holocene semiarid period. LU/LC changes such as deforestation in Australia increased recharge up to about 2 orders of magnitude. Changes from natural grassland and shrublands to dryland (rain-fed) agriculture altered systems from discharge (evapotranspiration, ET) to recharge in

  9. Salma Hegga: Identifying adaptation strategies for semi-arid regions ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    2015-02-18

    Feb 18, 2015 ... Salma Hegga is a postdoctoral research fellow working with a consortium on ... to carry out research and policy engagement in climate change hot spots. ... Together with teams from Southern, Western, and Eastern Africa, and ...

  10. Energy and Economic Performance of Plant-Shaded Building Façade in Hot Arid Climate

    Directory of Open Access Journals (Sweden)

    Mahmoud Haggag

    2017-11-01

    Full Text Available The use of vegetated walls and intensive plantation around buildings has increased in popularity in hot and arid climates, such as those in the United Arab Emirates (UAE. This is due to its contribution towards reducing the heat gain and increasing the occupants’ comfort levels in spaces. This paper examines the introduction of plant-shaded walls as passive technique to reduce heat gain in indoor spaces as a strategy to lower cooling demand in hot arid climate of Al-Ain city. Experimental work was carried out to analyze the impact of using plantation for solar control of residential building façades in extreme summer. External and internal wall surface and ambient temperatures were measured for plant-shaded and bare walls. The study concluded that shading effect of the intensive plantation can reduce peak time indoor air temperature by 12 °C and reduce the internal heat gain by 2 kWh daily in the tested space. The economic analysis reveals a payback period of 10 years considering local energy tariff excluding environmental savings.

  11. Progress and prospects of climate change impacts on hydrology in the arid region of northwest China.

    Science.gov (United States)

    Chen, Yaning; Li, Zhi; Fan, Yuting; Wang, Huaijun; Deng, Haijun

    2015-05-01

    The arid region of Northwest China, located in the central Asia, responds sensitively to global climate change. Based on the newest research results, this paper analyzes the impacts of climate change on hydrology and the water cycle in the arid region of Northwest China. The analysis results show that: (1) In the northwest arid region, temperature and precipitation experienced "sharply" increasing in the past 50 years. The precipitation trend changed in 1987, and since then has been in a state of high volatility, during the 21st century, the increasing rate of precipitation was diminished. Temperature experienced a "sharply" increase in 1997; however, this sharp increasing trend has turned to an apparent hiatus since the 21st century. The dramatic rise in winter temperatures in the northwest arid region is an important reason for the rise in the average annual temperature, and substantial increases in extreme winter minimum temperature play an important role in the rising average winter temperature; (2) There was a significant turning point in the change of pan evaporation in the northwest arid area in 1993, i.e., in which a significant decline reversed to a significant upward trend. In the 21st century, the negative effects of global warming and increasing levels of evaporation on the ecology of the northwest arid region have been highlighted; (3) Glacier change has a significant impact on hydrology in the northwest arid area, and glacier inflection points have appeared in some rivers. The melting water supply of the Tarim River Basin possesses a large portion of water supplies (about 50%). In the future, the amount of surface water will probably remain at a high state of fluctuation. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Lake Area Changes and Their Influence on Factors in Arid and Semi-Arid Regions along the Silk Road

    Directory of Open Access Journals (Sweden)

    Chao Tan

    2018-04-01

    Full Text Available In the context of global warming, the changes in major lakes and their responses to the influence factors in arid and semi-arid regions along the Silk Road are especially important for the sustainable development of local water resources. In this study, the areas of 24 lakes were extracted using MODIS NDVI data, and their spatial-temporal characteristics were analyzed. In addition, the relationship between lake areas and the influence factors, including air temperature, precipitation, evapotranspiration, land use and land cover change (LULCC and population density in the watersheds, were investigated. The results indicated that the areas of most lakes shrank, and the total area decreased by 22,189.7 km2 from 2001 to 2016, except for those of the lakes located on the Qinghai-Tibetan Plateau. The air temperature was the most important factor for all the lakes and increased at a rate of 0.113 °C/a during the past 16 years. LULCC and the increasing population density markedly influenced the lakes located in the middle to western parts of this study area. Therefore, our results connecting lake area changes in the study region highlight the great challenge of water resources and the urgency of implementation of the green policy in the One Belt and One Road Initiative through international collaboration.

  13. [Soil quality assessment under different cropping system and straw management in farmland of arid oasis region].

    Science.gov (United States)

    Zhang, Peng Peng; Pu, Xiao Zhen; Zhang, Wang Feng

    2018-03-01

    To reveal the regulatory mechanism of agricultural management practices on soil quality, an experiment was carried out to study the different cropping system and straw management on soil organic carbon and fractions and soil enzyme activity in farmland of arid oasis region, which would provide a scientific basic for enhancing agricultural resources utilization and sustainable development. In crop planting planning area, we took the mainly crop (cotton, wheat, maize) as research objects and designed long-term continues cropping and crop rotation experiments. The results showed that the soil organic carbon (SOC), soil microbial biomass C, labile C, water-soluble organic C, and hot-water-soluble organic C content were increased by 3.6%-9.9%, 41.8%-98.9%, 3.3%-17.0%, 11.1%-32.4%, 4.6%-27.5% by crop rotation compared to continues cropping, and 12%-35.9%, 22.4%-49.7%, 30.7%-51.0%, 10.6%-31.9%, 41.0%-96.4% by straw incorporated compared to straw removed, respectively. The soil catalase, dehydrogenase, β-glucosidase, invertase glucose, cellulase glucose activity were increased by 6.4%-10.9%, 6.6%-18.8%, 5.9%-15.3%, 10.0%-27.4%, 28.1%-37.5% by crop rotation compared to continues cropping, and 31.4%-47.5%, 19.9%-46.6%, 13.8%-20.7%, 19.8%-55.6%, 54.1%-70.9% by straw incorporated compared to straw removed, respectively. There were significant positive linear correlations among SOC, labile SOC fractions and soil enzyme. Therefore, we concluded that labile SOC fractions and soil enzyme were effective index for evaluating the change of SOC and soil quality. Based on factor analysis, in arid region, developing agricultural production using cropland management measures, such as straw-incorporated and combined short-term continues cotton and crop rotation, could enhance SOC and labile SOC fractions contents and soil enzyme activity, which could improve soil quality and be conducive to agricultural sustainable development.

  14. Integrated Scenarios of Regional Development in Two Semi-Arid States of North-Eastern Brazil

    NARCIS (Netherlands)

    Döll, Petra; Krol, Martinus S.

    2002-01-01

    Scenario analysis of the future is an important tool for supporting sustainability-oriented regional planning. To assist regional planning in two federal states in semi-arid North-eastern Brazil, Ceará and Piauí, we developed integrated qualitative¿quantitative scenarios that show potential

  15. Identification of suitable sites for rainwater harvesting structures in arid and semi-arid regions: A review

    Directory of Open Access Journals (Sweden)

    Ammar Adham

    2016-06-01

    Full Text Available Harvested rainwater is an alternative source of water in arid and semi-arid regions (ASARs around the world. Many researchers have developed and applied various methodologies and criteria to identify suitable sites and techniques for rainwater harvesting (RWH. Determining the best method or guidelines for site selection, however, is difficult. The main objective of this study was to define a general method for selecting suitable RWH sites in ASARs by assembling an inventory of the main methods and criteria developed during the last three decades. We categorised and compared four main methodologies of site selection from 48 studies published in scientific journals, reports of international organisations, or sources of information obtained from practitioners. We then identified three main sets of criteria for selecting RWH locations and the main characteristics of the most common RWH techniques used in ASARs. The methods were diverse, ranging from those based only on biophysical criteria to more integrated approaches including socio-economic criteria, especially after 2000. The most important criteria for the selection of suitable sites for RWH were slope, land use/cover, soil type, rainfall, distance to settlements/streams, and cost. The success rate of RWH projects tended to increase when these criteria were considered, but an objective evaluation of these selection methods is still lacking. Most studies now select RHW sites using geographic information systems in combination with hydrological models and multi-criteria analysis.

  16. On the Role of Hyper-arid Regions within the Virtual Water Trade Network

    Science.gov (United States)

    Aggrey, James; Alshamsi, Aamena; Molini, Annalisa

    2016-04-01

    Climate change, economic development, and population growth are bound to increasingly impact global water resources, posing a significant threat to the sustainable development of arid regions, where water consumption highly exceeds the natural carrying capacity, population growth rate is high, and climate variability is going to impact both water consumption and availability. Virtual Water Trade (VWT) - i.e. the international trade network of water-intensive products - has been proposed as a possible solution to optimize the allocation of water resources on the global scale. By increasing food availability and lowering food prices it may in fact help the rapid development of water-scarce regions. The structure of the VWT network has been analyzed by a number of authors both in connection with trade policies, socioeconomic constrains and agricultural efficiency. However a systematic analysis of the structure and the dynamics of the VWT network conditional to aridity, climatic forcing and energy availability, is still missing. Our goal is hence to analyze the role of arid and hyper-arid regions within the VWN under diverse climatic, demographic, and energy constraints with an aim to contribute to the ongoing Energy-Water-Food nexus discussion. In particular, we focus on the hyper-arid lands of the Arabian Peninsula, the role they play in the global network and the assessment of their specific criticalities, as reflected in the VWN resilience.

  17. Numerical analysis of the efficiency of earth to air heat exchange systems in cold and hot-arid climates

    International Nuclear Information System (INIS)

    Fazlikhani, Faezeh; Goudarzi, Hossein; Solgi, Ebrahim

    2017-01-01

    Highlights: • A numerical model is developed to evaluate performance of earth to air heat exchanger. • The cooling/heating potential of earth to air heat exchanger is investigated in hot-dry and cold climates. • The more performance of earth to air heat exchanger in hot-dry climates compared to cold climates. • The high efficiency of earth to air heat exchanger for pre-heating in both hot-dry and cold climates. - Abstract: In order to examine and compare the efficiency of earth to air heat exchanger (EAHE) systems in hot-arid (Yazd) and cold (Hamadan) climates in Iran a steady state model was developed to evaluate the impact of various parameters including inlet air temperatures, pipe lengths and ground temperatures on the cooling and heating potential of EAHEs in both climates. The results demonstrated the ability of the system to not only improve the average temperature and decrease the temperature fluctuation of the outlet air temperature of EAHE, but also to trigger considerable energy saving. It was found that in both climates, the system is highly utilized for pre-heating, and its usage is unfeasible in certain periods throughout the year. In winter, EAHEs have the potential of increasing the air temperature in the range of 0.2–11.2 °C and 0.1–17.2 °C for Yazd and Hamadan, respectively. However, in summer, the system decreases the air temperature for the aforementioned cities in the range of 1.3–11.4 °C and 5.7–11.1 °C, respectively. The system ascertains to be more efficient in the hot-arid climate of Yazd, where it can be used on 294 days of the year, leading to 50.1–63.6% energy saving, when compared to the cold climate of Hamadan, where it can be used on 225 days of the year resulting in a reduction of energy consumption by 24.5–47.9%.

  18. Consistency between Sweat Rate and Wet Bulb Globe Temperature for the Assessment of Heat Stress of People Working Outdoor in Arid and Semi-arid Regions

    Directory of Open Access Journals (Sweden)

    Hamidreza Heidari

    2018-01-01

    Full Text Available Background: Heat stress is common among workers in arid and semi-arid areas. In order to take every preventive measure to protect exposed workers against heat-related disorders, it is crucial to choose an appropriate index that accurately relates environmental parameters to physiological responses. Objective: To investigate the consistency between 2 heat stress and strain indices, ie, sweat rate and wet bulb globe temperature (WBGT, for the assessment of heat stress of people working outdoor in arid and semi-arid regions in Iran. Methods: During spring and summer, 136 randomly selected outdoor workers were enrolled in this study. Using a defined protocol, the sweat rate of these workers was measured 3 times a day. Simultaneously, the environmental parameters including WBGT index were recorded for each working station. Results: The level of agreement between sweat rate and WBGT was poor (κ<0.2. Based on sweat rate, no case exceeding the reference value was observed during the study. WBGT overestimated the heat stress in outdoor workers compared to sweat rate. Conclusion: It seems that the sweat rate standards may need some modifications related to real condition of work in arid and semi-arid regions in Iran. Moreover, it seems that judging workers solely based on monitoring their sweat rate in such regions, can probably result in underestimation of heat stress.

  19. Pedotransfer functions to estimate soil water content at field capacity and permanent wilting point in hot Arid Western India

    Science.gov (United States)

    Santra, Priyabrata; Kumar, Mahesh; Kumawat, R. N.; Painuli, D. K.; Hati, K. M.; Heuvelink, G. B. M.; Batjes, N. H.

    2018-04-01

    Characterization of soil water retention, e.g., water content at field capacity (FC) and permanent wilting point (PWP) over a landscape plays a key role in efficient utilization of available scarce water resources in dry land agriculture; however, direct measurement thereof for multiple locations in the field is not always feasible. Therefore, pedotransfer functions (PTFs) were developed to estimate soil water retention at FC and PWP for dryland soils of India. A soil database available for Arid Western India ( N=370) was used to develop PTFs. The developed PTFs were tested in two independent datasets from arid regions of India ( N=36) and an arid region of USA ( N=1789). While testing these PTFs using independent data from India, root mean square error (RMSE) was found to be 2.65 and 1.08 for FC and PWP, respectively, whereas for most of the tested `established' PTFs, the RMSE was >3.41 and >1.15, respectively. Performance of the developed PTFs from the independent dataset from USA was comparable with estimates derived from `established' PTFs. For wide applicability of the developed PTFs, a user-friendly soil moisture calculator was developed. The PTFs developed in this study may be quite useful to farmers for scheduling irrigation water as per soil type.

  20. Nuclear applications for the management of aquifers in the semi-arid region

    International Nuclear Information System (INIS)

    Simoes Filho, Fernando Lamego

    2005-01-01

    The semi-arid region of the Northeast of Brazil is characterized by a lack of superficial waters due to the low pluviometric precipitation and high evaporation rates. In addition to this, the precipitation events are irregular in time causing long periods of dryness or flooding with catastrophic consequences. Owing to adverse climatic conditions with recurrent droughts, intense pressure is being put on the use of groundwater resources. Groundwater occurrence on its turn depends on a series of geological and climatological characteristics that are very variable in the region. Because of this situation, groundwater is of strategical importance and represents a vital factor to its socioeconomic development. However, there is still insufficient knowledge of the basic aquifers characteristics leading to an over exploitation of the water resources. It is not surprising that, amongst other reasons, this situation contributes to the fact that areas with the lowest human development pattern are located in the semi-arid region of Brazil. Given the nature of hydrological problems that need to be addressed in semi-arid regions, nuclear/isotope techniques are increasingly recognized as indispensable tools for water resources assessment and development. However, information arising from these techniques has to cope with other hydrological methods in an integrated manner. The general objective was prospect nuclear technologies as tools for aquifer management, promoting sustainable use of groundwater in the semi-arid region. (author)

  1. JOJOBA: an oil plant for arid or semi-arid regions

    Energy Technology Data Exchange (ETDEWEB)

    Marull, J E

    1978-01-01

    Jojoba (Simmondsia chinesis) grows in regions with a rainfall of 250 to 450 mm, producing 4.5 kg seeds/tree after 36 months and attaining an average production of 13.8 kg seeds/tree when full grown. Productivity can be maintained for up to 100 years. Planting density is about 1600 plants/ha, at distances of 1.50 x 3.00 m. The seeds contain 50% edible oil, and the press-cake 35% proteins. The characteristics of the oil are listed.

  2. Jojoba, an oil plant for arid or semi-arid regions

    Energy Technology Data Exchange (ETDEWEB)

    Marull, J E

    1978-01-01

    Jojoba (Simmondsia chinensis) grows in regions with a rainfall of 250-450 mm, producing 4.5 kg seeds/tree after 36 months and attaining an average production of 13.8 kg seeds/tree when full grown. Productivity can be maintained for up to 100 years. Planting density is about 1600 plants/ha, at distances of 1.50 x 3.00 m. The seeds contain 50% edible oil, and the press-cake 35% proteins. The characteristics of the oil are listed.

  3. Climate change impacts on freshwater wetland hydrology and vegetation cover cycling along a regional aridity gradient

    Science.gov (United States)

    Global mean temperature may increase up to 6°C by the end of this century and together with precipitation change may steepen regional aridity gradients, impacting the hydrology, productivity, diversity, and ecosystem goods and services from freshwater wetlands, where the water balance is tightly cou...

  4. Hydrological modeling in semi-arid region using HEC-HMS model ...

    African Journals Online (AJOL)

    The purpose of this study is to simulate rainfall-runoff in the semi-arid region of ... the frequency storm is used for the meteorological model, the SCS curve number is ... SCS unit hydrograph method have been applied to simulate the runoff rate.

  5. An automated microlysimeter to study dew formation and evaporation in arid and semiarid regions

    NARCIS (Netherlands)

    Heusinkveld, B.G.; Berkowicz, S.M.; Jacobs, A.F.G.; Holtslag, A.A.M.; Hillen, W.C.A.M.

    2006-01-01

    The development of a simple and low-cost portable weighing microlysimeter that makes use of a load cell for automated recording and for studying daily dew formation, rate of accumulation, and subsequent evaporation in arid or semiarid regions during rainless seasons is presented. The sampling cup is

  6. 1 Title page Title: Groundwater quality in a semi-arid region of India ...

    Indian Academy of Sciences (India)

    64

    Groundwater quality in a semi-arid region of India - suitability for drinking, ... concentration ranges from 0.1 to 4.4 mg/L and 39% of the total samples measured ..... on identifying local priorities and implementing proper management is very.

  7. Woody plants in agro-ecosystems of semi-arid regions

    NARCIS (Netherlands)

    Breman, H.; Kessler, J.J.

    1995-01-01

    A quantitative analysis of the role of woody plants in semi-arid regions, focusing on the Sahel and Sudan zones in West-Africa, is given for the assessment of their benefits in agro-sylvopastoral land-use systems with productive and sustainability objectives.

  8. An overview of the floristic richness and conservation of the arid regions of northern Mexico

    Science.gov (United States)

    Laura Arriaga; Elizabeth Moreno; Claudia Aguilar

    2005-01-01

    The arid and semiarid regions of Northern Mexico harbor diverse, highly endemic, and geographically complex ecosystems. These share topographic and biogeographic similarities that can be used as an analytical framework to assess biodiversity patterns. This study presents the current status of vascular plant inventories for Mexican Aridamerica. The spatial distribution...

  9. Semi-arid Northeast Brazil: integrated modelling of regional development and global change impacts

    NARCIS (Netherlands)

    Krol, Martinus S.; Fuhr, Dagmar; Döring, Andreas; Unruh, Jon D.; Krol, Maarten S.; Kliot, Nurit

    2004-01-01

    Societies in semi-arid areas in developing regions are amongst those most vulnerable to climate variability and potentially most vulnerable to climate change. The vulnerability to climate variability emerges from a combination of the level of availability of natural resources and the human

  10. Too Much or Too Little? Eco-hydrology in Arid and Semi-arid Regions

    Science.gov (United States)

    Toch, S. L.

    2009-04-01

    Around the world, disastrous effects of floods and droughts are painful evidence of our continuing struggle between human resource demands and the sustainability of our hydrologic ecosystems. Too much or too little rainfall is often deemed the culprit in these water crises, focusing on water "lacks and needs" instead of exploring the diverse mechanisms of the hydrologic functions and processes that sustain us. Applicable to regions around the world, this unified approach focuses on the connections between our human and ecological qualities, with user friendly concepts and how-to guides backed up by real life experiences. From the poorest parts of Africa to Urban France to the wealthiest state in the USA, examples from surface to groundwater to marine environments demonstrate how the links between vulnerable natural areas, and the basins that they support are integral to the availability, adequacy and accessibility of our drinking water. The interactions of watersheds within our diverse communities can link our resource practices with our human needs, serving as a basis for our ecological health and human well-being. Hydrologic ecosystems provide links to geographic and cultural information traversing physical and social boundaries. This international, community-based project demonstrates how our human resource demands can be managed within ecological constraints. An inter-disciplinary process is used that specifically explores the connections between ecological integrity and the preservation of potable supplies. A monitoring strategy is developed that assesses risk to human health from resource use practices, and explores the similarities and interactions between our human needs and those of the ecosystems in which we all must live together. This work is geared as a reference for groups, individuals and agencies concerned with land use and watershed management, a supplement for interdisciplinary high school through University curriculum, for professional

  11. Diurnal regulation of photosynthesis in Jatropha curcas under drought during summer in a semi-arid region

    International Nuclear Information System (INIS)

    Tominaga, Jun; Inafuku, Sayuri; Coetzee, Tidimalo; Kawamitsu, Yoshinobu

    2014-01-01

    The diurnal photosynthetic responses to drought in Jatropha curcas have not been well assessed under field conditions in harsh semi-arid habitats. To illustrate this, diurnal changes in chlorophyll fluorescence and gas exchange rates were measured in field-grown Jatropha with or without a short (13 days) water recovery treatment under drought conditions during hot summer in a semi-arid. Sensitive stomatal closure coordinated with a drying atmosphere strictly limited a net CO 2 assimilation rate with a predominant morning peak, eventually turning negative during the day. Even though the risk of excess excitation energy which potentially causes photodamage increased with the extremely low capacity for CO 2 fixation, Jatropha preserved the integrity of PSII. Quantitative analysis of quenching partitioning revealed that regulated thermal energy dissipation accounted a large fraction of both instantaneous and daily absorbed energy by up to 80 and 72%, respectively, under the drought condition. Water recovery treatment more than doubled daily CO 2 uptake via mitigating diurnal stomatal closure. The regulated thermal dissipation flexibly adjusted PSII quantum efficiency to capacity of CO 2 fixation. In addition, downregulation of PSII quantum efficiency via sustained regulated thermal dissipation was observed and thought to be an additional photoprotective function. It is clear that Jatropha strongly rely upon the regulated thermal dissipation under drought condition, which must be critically important for this strict water conserving species, especially under a climate with high solar radiation loads as is seen in semi-arid regions. - Highlights: • Diurnal gas exchange and the fate of absorbed energy were assessed in Jatropha. • The dynamic stomatal closure was the predominant restriction under water stress. • The PSII integrity was preserved even under severe water stress. • The regulated thermal dissipation accounted by up to 72% of daily absorbed energy.

  12. The red edge in arid region vegetation: 340-1060 nm spectra

    Science.gov (United States)

    Ray, Terrill W.; Murray, Bruce C.; Chehbouni, A.; Njoku, Eni

    1993-01-01

    The remote sensing study of vegetated regions of the world has typically been focused on the use of broad-band vegetation indices such as NDVI. Various modifications of these indices have been developed in attempts to minimize the effect of soil background, e.g., SAVI, or to reduce the effect of the atmosphere, e.g., ARVI. Most of these indices depend on the so-called 'red edge,' the sharp transition between the strong absorption of chlorophyll pigment in visible wavelengths and the strong scattering in the near-infrared from the cellular structure of leaves. These broadband indices tend to become highly inaccurate as the green canopy cover becomes sparse. The advent of high spectral resolution remote sensing instrument such as the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) has allowed the detection of narrow spectral features in vegetation and there are reports of detection of the red edge even for pixels with very low levels of green vegetation cover by Vane et al. and Elvidge et al., and to characterize algal biomass in coastal areas. Spectral mixing approaches similar to those of Smith et al. can be extended into the high spectral resolution domain allowing for the analysis of more endmembers, and potentially, discrimination between material with narrow spectral differences. Vegetation in arid regions tends to be sparse, often with small leaves such as the creosote bush. Many types of arid region vegetation spend much of the year with their leaves in a senescent state, i.e., yellow, with lowered chlorophyll pigmentation. The sparseness of the leaves of many arid region plants has the dual effect of lowering the green leaf area which can be observed and of allowing more of the sub-shrub soil to be visible which further complicates the spectrum of a region covered with arid region vegetation. Elvidge examined the spectral characteristics of dry plant materials showing significant differences in the region of the red edge and the diagnostic ligno

  13. Soil water movement in the unsaturated zone of an inland arid region: Mulched drip irrigation experiment

    Science.gov (United States)

    Han, Dongmei; Zhou, Tiantian

    2018-04-01

    Agricultural irrigation with trans-basin water diversion can effectively relieve the water paucity in arid and semi-arid regions, however, this may be accompanied by eco-environmental problems (e.g., saline soils, rising groundwater levels, water quality problems). The mechanism of soil water movement under irrigation in the unsaturated zone of arid regions is a key scientific problem that should be solved in order to evaluate agricultural water management and further improve current irrigation practices. This study investigated the impact of drip irrigation on soil water movement in the unsaturated zone of a cotton field in an inland arid region (the Karamay Agricultural Development Area), northwest China. Combining in situ observational physical data with temporal variation in stable isotopic compositions of soil water, we described the soil water flow system and mechanism in severe (Plot 1) and mild (Plot 2) saline-alkali cotton fields. The infiltration depths are 0-150 cm for both plots. Drip irrigation scheduling makes no significant contribution to local groundwater recharge, however, groundwater can move into the unsaturated zone through capillary rise during cotton flowering and boll periods. Plot 2 is less prone to having secondary soil salinization than Plot 1 due to the existence of a middle layer (approximately 100 cm thick), which elongated the distance between the root zone and aquifer. Rise in the water table (approximately 60 cm for Plot 1 and 50 cm for Plot 2) could be caused by lateral groundwater flow instead of vertical infiltration. We estimated the soil water storage changes in the unsaturated zone and proposed a conceptual model for deciphering the movement process of soil water. This study provides a scientific basis for determining the rise of groundwater levels and potential development of saline soils and improving agricultural water management in arid regions.

  14. Comments on: The moisture from the air as water resource in arid region: hopes, doubt and facts

    NARCIS (Netherlands)

    Beysens, D.; Milimouk, I.; Nikolayev, V.; Berkowicz, S.M.; Muselli, M.; Heusinkveld, B.G.; Jacobs, A.F.G.

    2006-01-01

    Kogan and Trahtman [2003. The moisture from the air as water resource in arid region: hopes, doubts and facts. Journal of Arid Environments 53, 231¿240] analysed the functioning of a passive dew condenser built by F.I. Zibold in 1912 in Feodosia, and proposed a model to explain how thousands of

  15. Water Mapping Technology Rebuilds Lives in Arid Regions

    Science.gov (United States)

    2015-01-01

    Using NASA Landsat satellite and other remote sensing topographical data, Radar Technologies International developed an algorithm-based software program that can locate underground water sources. Working with international organizations and governments, the firm, which maintains an office in New Braunfels, Texas, is helping to provide water for refugees and other people in drought-stricken regions such as Kenya, Sudan, and Afghanistan.

  16. Groundwater quality in arid regions: The case of Hassi Messaoud ...

    African Journals Online (AJOL)

    After chemical quality study, it has been realized that the groundwater of Hassi Messaoud region isn't drinking one according to WHO and Algerian standards for drinking water. This water is highly mineralized and very hard and its major concentrations are often higher than recommended standards, so it requires treatment ...

  17. Some cirad activities and perspectives in water and nutrient management in arid and semi-arid regions using nuclear techniques

    International Nuclear Information System (INIS)

    Maraux, F.; Affholder, F.; Forest, F.; Ganry, F.; N'diaye, M.; Oliver, R.; Scopel, E.

    1998-01-01

    The Centre de Cooperation Internationale en Recherche Agronomique pour le Developpement has conducted collaborative research with national agricultural research services in several semi-arid regions that has led to a general understanding of the relationship between water consumption and growth, and crop responses to fertilizers. However, farmers' adoption of practices arising from the research has been minimal. Current effort is directed at overcoming limits to adoption, firstly by understanding the interaction of fertilizer response and water supply, especially through modelling, in order to quantify risk criteria from the farmer's point of view. Secondly, research now takes account of the whole cropping system, including labour availability, access to credit, livestock management, etc., with a multidisciplinary approach. Approaches that offer sustainability are improved intercropping systems, retention of crop residues, increased plant cover, and agroforestry. There are important technical gaps in understanding of how these systems should operate. The allocation of nutrients and water among the components of intercropped or agroforestry systems is not understood and solutions could lead to improved spatial arrangements. The integrated effects of residues on runoff, soil evaporation, crop transpiration and N mineralization are not quantified. In these and other problems, the full range of risks as well as benefits need to be evaluated. (author)

  18. Hot spots and heavily dislocated regions in multicrystalling silicon cells

    International Nuclear Information System (INIS)

    Simo, A.; Martinuzzi, S.

    1990-01-01

    The formation mechanism and the electrical consequences of hot spots have been investigated in multicrystalline solar cells. The hot spots were revealed by means of an infrared camera when the cells are reverse biassed in the dark. The minority carrier diffusion length (L n ), the photovoltage (V oc ) and the photocurrent (J sc ) were measured in the hot spot area and far from this zone thanks to mesa diodes. Dark forward I-V curves lead to values of ideality factor (M) and reverse saturation current (J o ). It is found that J o and M are higher in the hot spot area, while J sc , V oc and at a less extent L n are smaller. Large densities of dislocations and lineages structures are revealed in the abnormally heated regions

  19. Experimental Studies on Earthen Architecture Sites Consolidated with BS Materials in Arid Regions

    Directory of Open Access Journals (Sweden)

    Dong Zhao

    2016-01-01

    Full Text Available This paper takes the preservation works on the archaeological sites of Gaochang Ruins, Xinjiang, as background. Based on the soil characteristics analysis on the archaeological sites, experimental studies were conducted on the consolidation effect of the BS-10 consolidation material on the archaeological sites of adobe and rammed earth. The results showed the following:, after consolidation, the wind erosion resistance of the soil on the archaeological sites was substantially increased, and the wind erosion modulus was reduced by 5~8 times; the soil exhibited fine grid structure and significantly reduced degree of permeability, while still maintaining the moisture exchange between inside and outside the soil; there is excellent ageing resistance; the resistance to freezing and thawing was closely related to the soil water content and had little influence in arid regions; the water resistance was improved and could satisfy the requirements for consolidating the sites in arid regions; the unconfined compressive strength was improved moderately, which was the key direction of improvement in the future, and the consolidated soil did not form duricrust on the surface and had good bonding strength with the internal parts. The BS-10 material can meet the consolidation requirements for the earthen archaeological sites in arid regions of northwest China.

  20. Understanding Flash Flood Generation in the Arid Region of the Dead Sea

    Science.gov (United States)

    Merz, R.; Hennig, H.; Rödiger, T.; Laronne, J. B.

    2017-12-01

    The arid region of the Dead Sea is prone by flash floods. Such flash floods in (semi-) arid regions are impressive. Generated within minutes, the peak unit discharge can be as high as 25 m³/s km². Floods are the main mechanism supplying water to alluvial aquifers, forming fluvial landscapes including canyons and often causing damage to humans, infrastructure, industry and tourism. Existing hydrological models in this region focus on peak discharges. However, these models are often based on simplified concepts and/or on concepts which were developed for humid regions. To more closely relate such models to local conditions, processes within catchments where floods occur require consideration. Therefore, a measurement network of rain gauges and level loggers to monitor runoff was installed in the beginning of the 2015/16 hydrological season in the tributaries of Wadi Arugot. The Arugot catchment is one of the largest ephemeral Wadis draining to the western shoreline of the Dead Sea at 450 m bsl. Due to the high gradient in elevation, the climate within the basin ranges from semiarid in the Judean Mountains, to hyper-arid near the Dead Sea with respective mean annual rainfall of 650 and 50 mm. The installed rain gauge network in the mountains is more dense compared to the Dead Sea area. Arid to semiarid catchments have different runoff generation processes compared to humid regions due local storm rainfall, low density of vegetation cover as well as patchy and shallow soil. These characteristics limit the contribution of groundwater flow, saturated overland flow and shallow subsurface flow, and therefore Hortonian overland flow is the most important contributor to overland flow. First analyses of the runoff data have shown that the storage capacity in the mountain area is lower compared to the more arid region. This is an evidence of high transmission losses in the coarse gravel wadi bed, therefore having a high permeability. The rain event duration and the amount of

  1. Longevity and efficacy of bifenthrin treatment on desert-pattern US military camouflage netting against mosquitoes in a hot-arid environment.

    Science.gov (United States)

    Britch, Seth C; Linthicum, Kenneth J; Wynn, Willard W; Aldridge, Robert L; Walker, Todd W; Farooq, Muhammad; Dunford, James C; Smith, Vincent L; Robinson, Cathy A; Lothrop, Branka B; Snelling, Melissa; Gutierrez, Arturo; Wittie, Jeremy; White, Gregory

    2011-09-01

    The current Department of Defense pest management system does not provide adequate protection from arthropod disease vectors to personnel deployed in support of US military operations. We hypothesized that military camouflage netting, ubiquitous around living and working areas in current US military operations in Africa and the Middle East, treated with a residual pesticide such as bifenthrin may reduce the presence of biting insects and improve the military pest management system. In this study, we examined the longevity and efficacy of bifenthrin applied to camouflage netting material at the maximum label rate of 0.03 liter formulation (7.9% AI) per 92.9 m2 against field populations of mosquitoes in southern California in a hot-arid environment similar to regions of Iraq, Afghanistan, and the Horn of Africa. We showed that bifenthrin treatment of camouflage netting was effective at reducing mosquito populations, predominantly Psorophora columbiae and Aedes vexans, by an average of up to 46% for 56 days, and could cause as much as 40% mortality in Culex quinquefasciatus in laboratory bioassays for nearly 2 months postapplication. These population reductions could translate to commensurate reductions in risk of exposure to mosquito-borne pathogens, and could potentially be effective against sand flies and filth flies.

  2. Modeling water scarcity and droughts for policy adaptation to climate change in arid and semiarid regions

    Science.gov (United States)

    Kahil, Mohamed Taher; Dinar, Ariel; Albiac, Jose

    2015-03-01

    Growing water extractions combined with emerging demands for environment protection increase competition for scarce water resources worldwide, especially in arid and semiarid regions. In those regions, climate change is projected to exacerbate water scarcity and increase the recurrence and intensity of droughts. These circumstances call for methodologies that can support the design of sustainable water management. This paper presents a hydro-economic model that links a reduced form hydrological component, with economic and environmental components. The model is applied to an arid and semiarid basin in Southeastern Spain to analyze the effects of droughts and to assess alternative adaptation policies. Results indicate that drought events have large impacts on social welfare, with the main adjustments sustained by irrigation and the environment. The water market policy seems to be a suitable option to overcome the negative economic effects of droughts, although the environmental effects may weaken its advantages for society. The environmental water market policy, where water is acquired for the environment, is an appealing policy to reap the private benefits of markets while protecting ecosystems. The current water management approach in Spain, based on stakeholders' cooperation, achieves almost the same economic outcomes and better environmental outcomes compared to a pure water market. These findings call for a reconsideration of the current management in arid and semiarid basins around the world. The paper illustrates the potential of hydro-economic modeling for integrating the multiple dimensions of water resources, becoming a valuable tool in the advancement of sustainable water management policies.

  3. Effects of added organic matter and water on soil carbon sequestration in an arid region.

    Directory of Open Access Journals (Sweden)

    Liming Lai

    Full Text Available It is generally predicted that global warming will stimulate primary production and lead to more carbon (C inputs to soil. However, many studies have found that soil C does not necessarily increase with increased plant litter input. Precipitation has increased in arid central Asia, and is predicted to increase more, so we tested the effects of adding fresh organic matter (FOM and water on soil C sequestration in an arid region in northwest China. The results suggested that added FOM quickly decomposed and had minor effects on the soil organic carbon (SOC pool to a depth of 30 cm. Both FOM and water addition had significant effects on the soil microbial biomass. The soil microbial biomass increased with added FOM, reached a maximum, and then declined as the FOM decomposed. The FOM had a more significant stimulating effect on microbial biomass with water addition. Under the soil moisture ranges used in this experiment (21.0%-29.7%, FOM input was more important than water addition in the soil C mineralization process. We concluded that short-term FOM input into the belowground soil and water addition do not affect the SOC pool in shrubland in an arid region.

  4. Isotope and radiation techniques for efficient water and fertilizer use in semi-arid regions

    International Nuclear Information System (INIS)

    1986-04-01

    The Joint FAO/IAEA Division carried out a coordinated research programme, which was concerned with the efficiency of water and fertilizer uses in semi-arid farming systems. The present publication is a summary of the individual contributions from Belgium, Chile, Ivory Coast, Cyprus, France, India, Israel, Romania, Senegal, Sri Lanka and the United States of America, over the period 1978-1984. Water and fertilizer uptake by crops are dynamic processes affected by several factors of the soil-plant-atmosphere system. The neutron moisture meters were used not only to measure soil water contents but also to understand water dynamics under field conditions. Nitrogen is the most limiting nutrient in many semi-arid regions, and as its absorption is very much related to water dynamics in the soil, experiments using N-15 labelled fertilizer were carried out, which are presented in this report

  5. Assessment of the performance of water harvesting systems in semi-arid regions

    Science.gov (United States)

    Lasage, Ralph

    2016-04-01

    Water harvesting is widely practiced and has the potential to improve water availability for domestic and agricultural use in semi-arid regions. New funds are becoming available to stimulate the implementation of water harvesting projects, for meeting the Sustainable Development Goals and to help communities to adapt to climate change. For this, it is important to understand which factors determine the success of water harvesting techniques under different conditions. For this, we review the literature, including information on the crop yield impacts of water harvesting projects in semi-arid Africa and Asia. Results show that large water harvesting structures (> 500 m3) are less expensive than small structures, when taking into account investment costs, storage capacity and lifetimes. We also find that water harvesting improves crop yields significantly, and that the relative impact of water harvesting on crop yields is largest in low rainfall years. We also see that the governance, technical knowledge and initial investment are more demanding for the larger structures than for smaller structures, which may affect their spontaneous adoption and long term sustainability when managed by local communities. To support the selection of appropriate techniques, we present a decision framework based on case specific characteristics. This framework can also be used when reporting and evaluating the performance of water harvesting techniques, which is up to now quite limited in peer reviewed literature. Based on Bouma, J., Hegde, S.E., Lasage, R., (2016). Assessing the returns to water harvesting: A meta-analysis. Agricultural Water Management 163, 100-109. Lasage, R., Verburg P.H., (2015). Evaluation of small scale water harvesting techniques for semi-arid environments. Journal of Arid Environments 118, 48-57.

  6. Optimized estimation and its uncertainties of gross primary production over oasis-desert ecosystems in an arid region of China

    Science.gov (United States)

    Wang, H.; Li, X.; Xiao, J.; Ma, M.

    2017-12-01

    Arid and semi-arid ecosystems cover more than one-third of the Earth's land surface, it is of great important to the global carbon cycle. However, the magnitude of carbon sequestration and its contribution to global atmospheric carbon cycle is poorly understood due to the worldwide paucity of measurements of carbon exchange in the arid ecosystems. Accurate and continuous monitoring the production of arid ecosystem is of great importance for regional carbon cycle estimation. The MOD17A2 product provides high frequency observations of terrestrial Gross Primary Productivity (GPP) over the world. Although there have been plenty of studies to validate the MODIS GPP products with ground based measurements over a range of biome types, few have comprehensively validated the performance of MODIS estimates in arid and semi-arid ecosystems. Thus, this study examined the performance of the MODIS-derived GPP comparing with the EC observed GPP at different timescales for the main arid ecosystems in the arid and semi-arid ecosystems in China, and optimized the performance of the MODIS GPP calculations by using the in-situ metrological forcing data, and optimization of biome-specific parameters with the Bayesian approach. Our result revealed that the MOD17 algorithm could capture the broad trends of GPP at 8-day time scales for all investigated sites on the whole. However, the GPP product was underestimated in most ecosystems in the arid region, especially the irrigated cropland and forest ecosystems, while the desert ecosystem was overestimated in the arid region. On the annual time scale, the best performance was observed in grassland and cropland, followed by forest and desert ecosystems. On the 8-day timescale, the RMSE between MOD17 products and in-situ flux observations of all sites was 2.22 gC/m2/d, and R2 was 0.69. By using the in-situ metrological data driven, optimizing the biome-based parameters of the algorithm, we improved the performances of the MODIS GPP calculation

  7. Research summary: characterization of radionuclide and moisture movement through arid region sediments

    International Nuclear Information System (INIS)

    Gee, G.W.; Jones, T.L.; Rai, D.

    1981-09-01

    This project has the task of understanding the movement of moisture and radionuclides under arid region conditions. This understanding will be used to maximize the isolation of low level waste from the environment. Specific objectives include: field monitoring of moisture and radionuclide transport at an arid region site; assessment of the interaction of radionuclides with unsaturated soils in arid regions; evaluation of radionuclide transport in unsaturated soils by appropriate mathematical models; and assessment of the importance of upward migration of radionuclides by evaporation and diffusion processes. The Burial Waste Test Facility (BWTF) located near Richland, Washington, on the Department of Energy (DOE) Hanford Site has been monitored for water content and radionuclide transport for the past two years. Tritium movement has been observed to depths of 7.6 m in both irrigated and nonirrigated lysimeters. Laboratory tests were conducted to determine how leachate from uranium tailings interacts with geologic materials. Acid leach tailings and tailings solution and geologic materials typical of mill site tailing pits were physically and chemically characterized. Investigation was made of the sorption characteristics of heavy metals and radionuclides on the geologic materials under low and neutral pH conditions. From solubility tests conducted at Pacific Northwest Laboratory, thermodynamic considerations predicted that for the Eh-pH range of natural aqueous environment, the dominant species of Pu is likely to be Pu(V) in relatively oxidizing environments and Pu(III) in reducing environments. Radionuclide transport through unsaturated media was investigated by using two solute transport models to describe the transport of tritium and strontium-85 in laboratory columns. A new approach was used to analyze radon emissions from uranium mill tailings

  8. Physiological characteristics of three wild sonchus species to prolonged drought tolerance in arid regions

    International Nuclear Information System (INIS)

    Jia, P.Y.; Hu, Y.; Zhang, L.X.; Wu, G.L.

    2018-01-01

    Drought is one of the main abiotic factors determining plants growth and productivity in arid and semiarid regions. Understanding the physiological responses of wild plants to drought in different growth stages is essential to evaluate their ability of drought tolerance and allow identification and selection of valuable tolerant plants to be cultivated and introduced in arid and semiarid regions. Three wild Sonchus species, Sonchus oleraceus L., Sonchus wightianus DC. and Sonchus uliginosus M. B. were compared regarding some physiological indexes in leaves such as antioxidant enzymes (superoxide dismutase and peroxidase), malondialdehyde, osmotic solutes (proline, soluble sugar and soluble protein), photosynthetic pigments (total chlorophyll, chlorophyll a, chlorophyll b and carotenoid) under the natural condition at seeding stage, flowering stage and maturation stage respectively. Comparing to S. uliginosus and S. wightianus, S. oleraceus had the higher peroxidase (POD) and superoxide dismutase (SOD) activities and total chlorophyll (Chla+b) and carotenoid (Car) content in three growth stages, and the higher proline content at flowering and maturation stage and the lower malondialdehyde (MDA) content at seeding stage and flowering stage. But the ratio of Chla/Chlb and Car/Chla+b in S. uliginosus were significantly higher than that in S. oleraceus and S. wightianus. These findings suggested that S. oleraceus had the higher tolerance to prolonged drought than S. wightianus and S. uliginosus due to the better capacity to prevent oxidative damage to cellular components and osmoregulation and photosynthetic ability and S. uliginosus were more photo-protected under drought. The research results were instructive for cultivation and introduction of S. oleraceus in arid and semiarid regions. (author)

  9. Effectiveness of indirect evaporative cooling and thermal mass in a hot arid climate

    Energy Technology Data Exchange (ETDEWEB)

    Krueger, Eduardo [Programa de Pos-Graduacao em Tecnologia/Programa de Pos-Graduacao em Engenharia Civil, Departamento de Construcao Civil, Universidade Tecnologica Federal do Parana - UTFPR, Av. Sete de Setembro, 3165. Curitiba PR, CEP. 80230-901 (Brazil); Gonzalez Cruz, Eduardo [Instituto de Investigaciones de la Facultad de Arquitectura y Diseno (IFAD), Universidad del Zulia, Nucleo Tecnico de LUZ, Av. Goajira (16) con Calle 67, Maracaibo, CP 4011-A-526 (Venezuela); Givoni, Baruch [Department of Architecture, School of Arts and Architecture, UCLA, Los Angeles CA, USA, and Ben Gurion University (Israel)

    2010-06-15

    In this paper, we compare results of a long-term temperature monitoring in a building with high thermal mass to indoor temperature predictions of a second building that uses an indirect evaporative cooling system as a means of passive cooling (Vivienda Bioclimatica Prototipo -VBP-1), for the climatic conditions of Sde Boqer, Negev region of Israel (local latitude 30 52'N, longitude 34 46'E, approximately 480 m above sea level). The high-mass building was monitored from January through September 2006 and belongs to a student dormitory complex located at the Sde Boqer Campus of Ben-Gurion University. VBP-1 was designed and built in Maracaibo, Venezuela (latitude 10 34'N, longitude 71 44'W, elevation 66 m above sea level) and had its indoor air temperatures, below and above a shaded roof pond, as well as the pond temperature monitored from February to September 2006. Formulas were developed for the VBP-1, based on part of the whole monitoring period, which represent the measured daily indoor maximum, average and minimum temperatures. The formulas were then validated against measurements taken independently in different time periods. The developed formulas were here used for estimating the building's thermal and energy performance at the climate of Sde Boqer, allowing a comparison of two different strategies: indirect evaporative cooling and the use of thermal mass. (author)

  10. A late Holocene record of arid events from the Cuzco region, Peru

    Science.gov (United States)

    Chepstow-Lusty, Alex; Frogley, Michael R.; Bauer, Brian S.; Bush, Mark. B.; Tupayachi Herrera, Alfredo

    2003-09-01

    The small recently infilled lake basin of Marcacocha (13°13S, 72°12W, 3355 m) in the Cuzco region of Peru has a morphology and location that renders it extremely sensitive to environmental change. A record of vegetation, human impact and climatic change during the past 4200 yr has been obtained from a highly organic core taken from the centre of the basin. Sustained arid episodes that affected the Peruvian Andes may be detectable using the proxy indicator of sedge (Cyperaceae) pollen abundances. As the lake-level was lowered during sustained drier conditions, the local catchment was colonised by Cyperaceae, whereas during lake floods, they retreated or were submerged and pollen production was correspondingly reduced. Drier episodes during prehistoric times occurred around 900 bc, 500 bc, ad 100 and ad 550, with a longer dry episode occurring from ad 900 to 1800. Evidence from the independently derived Quelccaya ice-core record and the archaeological chronology for the Cuzco region appears to support the climatic inferences derived from the sedge data. Many of these aridity episodes appear to correspond with important cultural changes in the Cuzco region and elsewhere in the Central Andes. Copyright

  11. Genetic improvement of Nellore cattle in the semi-arid region of northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Ana Carla Borges Barbosa

    2015-08-01

    Full Text Available The semi-arid region of Brazil represents approximately 57% of the northeastern territory. The main economic activity in this region is agriculture and livestock, in most cases, using traditional technologies. However, there is little published information currently available on cattle-raising in this part of Brazil. The objective of this study was to estimate genetic parameters and trends for productive and reproductive traits of Nellore cattle raised in semi-arid region of northeastern Brazil. Data were collected on weight-adjusted at 205 (W205, 365 (W365 and 550 (W550 days of life, age at first calving (AFC, calving interval (CI and scrotal circumference (SC at 550 days of life of cattle born between 1965 and 2011. Estimates of covariance and variance were obtained through univariate analysis using a Gibbs sampler. The estimated coefficients of heritability (mode were 0.27 (W205, 0.36 (W365 and 0.39 (W550, 0.37 (SC, 0.22 (AFC and 0.03 (CI. Little or no gain from selection is apparent in the genetic trend analysis over the 45 years of the study. However, environmental improvement has allowed phenotypic progress in growth traits and age at first age calving.

  12. Isotopic composition of groundwater in semi-arid regions of Southern Africa

    International Nuclear Information System (INIS)

    Vogel, J.C.; Urk, H. van

    1975-01-01

    Although the isotope content of precipitation in the semi-arid regions of southern Africa is extremely variable, groundwater samples from the same district are found to have a remarkably constant isotopic composition. The oxygen-18 content of the underground water, in general, varies by about 0.5% in a given area. The differences that occur between different regions are sufficiently large to allow the groundwater of an area to be characterized by means of its oxygen-18 content. In order to localize the infiltration area of an aquifer, radiocarbon dating of the water is used. It appears that the groundwater contains, in general, less of the heavy isotopes than does the precipitation in the recharge area. This indicates that infiltration only takes place during periods of heavy rainfall. Examples are given where the isotope content of the groundwater is used to distinguish between different aquifers in the same region

  13. Nuclear-waste isolation in the unsaturated zone of arid regions

    International Nuclear Information System (INIS)

    Wollenberg, H.A.; Wang, J.S.Y.; Korbin, G.

    1982-05-01

    The vadose zone in arid regions is considered as a possible environment for geologic isolation of nuclear waste. There are several topographic and lithologic combinations in the vadose zone of arid regions that may lend themselves to waste isolation considerations. In some cases, topographic highs such as mesas and interbasin ranges - comprised of several rock types, may contain essentially dry or partially saturated conditions favorable for isolation. The adjacent basins, especially in the far western and southwestern US, may have no surface or subsurface hydrologic connections with systems ultimately leading to the ocean. Some rock types may have the favorable characteristics of very low permeability and contain appropriate minerals for the strong chemical retardation of radionuclides. Environments exhibiting these hydrologic and geochemical attributes are the areas underlain by tuffaceous rocks, relatively common in the Basin and Range geomorphic province. Adjacent valley areas, where tuffaceous debris makes up a significant component of valley fill alluvium, may also contain thick zones of unsaturated material, and as such also lend themselves to strong consideration as respository environments. This paper summarizes the aspects of nuclear waste isolation in unsaturated regimes in alluvial-filled valleys and tuffaceous rocks of the Basin and Range province

  14. Do invasive riparian Tamarix alter hydrology of riparian areas of arid and semi-arid regions under climate change scenarios?

    Science.gov (United States)

    Bhattarai, M. P.; Acharya, K.; Chen, L.

    2012-12-01

    Competitiveness of riparian invasive species, Tamarix, in arid and semi-arid riparian areas of the southwestern United States under climate change scenario (SRES A2) was investigated. Tamarix has been replacing native vegetation along the riparian corridors of these areas for the past several decades and is thought to alter water balance. Changes in depth to groundwater, soil moisture distribution and flood frequency are critical in survival and growth of a facultative phreatophyte such as Tamarix. In this study, a fully coupled 2d surface flow and 3d subsurface flow hydrologic model, HydroGeoSphere, was used to simulate surface-subsurface hydrology of the lower Virgin River basin (4500 sq. km), located in Nevada, Utah and Arizona. The hydrologic model results, depth to groundwater and soil saturation, were then applied to the species distribution model, Maxent, along with other bioclimatic parameters to asses future Tamarix distribution probability. Simulations were made for the climate scenarios of the end of 21st centry conditions. Depth to groundwater is found to be the most important predictor variable to the Maxent model. Future Tamarix distribution range is not uniform across the basin. It is likely to decrease at lower elevations and increase in some higher elevation areas.

  15. Quantifying recycled moisture fraction in precipitation of an arid region using deuterium excess

    Directory of Open Access Journals (Sweden)

    Yanlong Kong

    2013-01-01

    Full Text Available Terrestrial moisture recycling by evapotranspiration has recently been recognised as an important source of precipitation that can be characterised by its isotopic composition. Up to now, this isotope technique has mainly been applied to moisture recycling in some humid regions, including Brazil, Great Lakes in North America and the European Alps. In arid and semi-arid regions, the contribution of transpiration by plants to local moisture recycling can be small, so that evaporation by bare soil and surface water bodies dominates. Recognising that the deuterium excess (d-excess of evaporated moisture is significantly different from that of the original water, we made an attempt to use this isotopic parameter for estimating moisture recycling in the semi-arid region of Eastern Tianshan, China. We measured the d-excess of samples taken from individual precipitation events during a hydrological year from 2003 to 2004 at two Tianshan mountain stations, and we used long-term monthly average values of the d-excess for the station Urumqi, which are available from the International Atomic Energy Agency–World Meteorological Organization (IAEA–WMO Global Network of Isotopes in Precipitation (GNIP. Since apart from recycling of moisture from the ground, sub-cloud evaporation of falling raindrops also affects the d-excess of precipitation, the measured values had to be corrected for this evaporation effect. For the selected stations, the sub-cloud evaporation was found to change between 0.1 and 3.8%, and the d-excess decreased linearly with increasing sub-cloud evaporation at about 1.1‰ per 1% change of sub-cloud evaporation. Assuming simple mixing between advected and recycled moisture, the recycled fraction in precipitation has been estimated to be less than 2.0±0.6% for the Tianshan mountain stations and reach values up to 15.0±0.7% in the Urumqi region. The article includes a discussion of these findings in the context of water cycling in the

  16. Effects of rainfall on bird reproduction in a semi-arid Neotropical region

    Directory of Open Access Journals (Sweden)

    Liana Monique Paiva Cavalcanti

    Full Text Available ABSTRACT In semi-arid ecosystems, birds commonly use rainfall as a reliable environmental cue to adjust the timing and strength of their reproductive activity. Here we evaluate this hypothesis for a community of birds in the Caatinga (the semi-arid region of northeastern Brazil, using brood patch information and nest abundance. Sampling occurred every 14 days between September 2012 and August 2013 (brood patch, and every three or four days during the reproductive period (nests. Abundance of brood patches and nests were correlated, and all brood patches were recorded between March and July (4.5 to 5.0 months. We recorded three peaks of brood patch abundance: the first 28 days after the first rains, the second 14 days after the second rainfall peak, and the third synchronously with the third rainy period. These results indicate that intra-annual variation in local rainfall has the potential to account for variations in the timing and intensity of reproduction in the studied birds.

  17. Trends and homogeneity of monthly, seasonal, and annual rainfall over arid region of Rajasthan, India

    Science.gov (United States)

    Meena, Hari Mohan; Machiwal, Deepesh; Santra, Priyabrata; Moharana, Pratap Chandra; Singh, D. V.

    2018-05-01

    Knowledge of rainfall variability is important for regional-scale planning and management of water resources in agriculture. This study explores spatio-temporal variations, trends, and homogeneity in monthly, seasonal, and annual rainfall series of 62 stations located in arid region of Rajasthan, India using 55 year (1957-2011) data. Box-whisker plots indicate presence of outliers and extremes in annual rainfall, which made the distribution of annual rainfall right-skewed. Mean and coefficient of variation (CV) of rainfall reveals a high inter-annual variability (CV > 200%) in the western portion where the mean annual rainfall is very low. A general gradient of the mean monthly, seasonal, and annual rainfall is visible from northwest to southeast direction, which is orthogonal to the gradient of CV. The Sen's innovative trend test is found over-sensitive in evaluating statistical significance of the rainfall trends, while the Mann-Kendall test identifies significantly increasing rainfall trends in June and September. Rainfall in July shows prominently decreasing trends although none of them are found statistically significant. Monsoon and annual rainfall show significantly increasing trends at only four stations. The magnitude of trends indicates that the rainfall is increasing at a mean rate of 1.11, 2.85, and 2.89 mm year-1 in August, monsoon season, and annual series. The rainfall is found homogeneous over most of the area except for few stations situated in the eastern and northwest portions where significantly increasing trends are observed. Findings of this study indicate that there are few increasing trends in rainfall of this Indian arid region.

  18. Regional Cost Estimates for Reclamation Practices on Arid and Semiarid Lands; TOPICAL

    International Nuclear Information System (INIS)

    W. K. Ostler

    2002-01-01

    The U.S. Army uses the Integrated Training Area Management program for managing training land. One of the major objectives of the Integrated Training Area Management program has been to develop a method for estimating training land carrying capacity in a sustainable manner. The Army Training and Testing Area Carrying Capacity methodology measures training load in terms of Maneuver Impact Miles. One Maneuver Impact Mile is the equivalent impact of an M1A2 tank traveling one mile while participating in an armor battalion field training exercise. The Army Training and Testing Area Carrying Capacity methodology is also designed to predict land maintenance costs in terms of dollars per Maneuver Impact Mile. The overall cost factor is calculated using the historical cost of land maintenance practices and the effectiveness of controlling erosion. Because land maintenance costs and effectiveness are influenced by the characteristics of the land, Army Training and Testing Area Carrying Capacity cost factors must be developed for each ecological region of the country. Costs for land maintenance activities are presented here for the semiarid and arid regions of the United States. Five ecoregions are recognized, and average values for reclamation activities are presented. Because there are many variables that can influence costs, ranges for reclamation activities are also presented. Costs are broken down into six major categories: seedbed preparation, fertilization, seeding, planting, mulching, and supplemental erosion control. Costs for most land reclamation practices and materials varied widely within and between ecological provinces. Although regional cost patterns were evident for some practices, the patterns were not consistent between practices. For the purpose of estimating land reclamation costs for the Army Training and Testing Area Carrying Capacity methodology, it may be desirable to use the ''Combined Average'' of all provinces found in the last row of each table

  19. Improving satellite-based post-fire evapotranspiration estimates in semi-arid regions

    Science.gov (United States)

    Poon, P.; Kinoshita, A. M.

    2017-12-01

    Climate change and anthropogenic factors contribute to the increased frequency, duration, and size of wildfires, which can alter ecosystem and hydrological processes. The loss of vegetation canopy and ground cover reduces interception and alters evapotranspiration (ET) dynamics in riparian areas, which can impact rainfall-runoff partitioning. Previous research evaluated the spatial and temporal trends of ET based on burn severity and observed an annual decrease of 120 mm on average for three years after fire. Building upon these results, this research focuses on the Coyote Fire in San Diego, California (USA), which burned a total of 76 km2 in 2003 to calibrate and improve satellite-based ET estimates in semi-arid regions affected by wildfire. The current work utilizes satellite-based products and techniques such as the Google Earth Engine Application programming interface (API). Various ET models (ie. Operational Simplified Surface Energy Balance Model (SSEBop)) are compared to the latent heat flux from two AmeriFlux eddy covariance towers, Sky Oaks Young (US-SO3), and Old Stand (US-SO2), from 2000 - 2015. The Old Stand tower has a low burn severity and the Young Stand tower has a moderate to high burn severity. Both towers are used to validate spatial ET estimates. Furthermore, variables and indices, such as Enhanced Vegetation Index (EVI), Normalized Difference Moisture Index (NDMI), and the Normalized Burn Ratio (NBR) are utilized to evaluate satellite-based ET through a multivariate statistical analysis at both sites. This point-scale study will able to improve ET estimates in spatially diverse regions. Results from this research will contribute to the development of a post-wildfire ET model for semi-arid regions. Accurate estimates of post-fire ET will provide a better representation of vegetation and hydrologic recovery, which can be used to improve hydrologic models and predictions.

  20. Amphibian and reptile biodiversity in the semi-arid region of the municipality of Nopala de Villagrán, Hidalgo, Mexico

    OpenAIRE

    Roth-Monzón, Andrea J.; Mendoza-Hernández, Andrés Alberto; Flores-Villela, Oscar

    2018-01-01

    Current global changes are putting both biodiversity and the processes that depend on it at risk. This is especially true for semi-arid regions and the flagship groups that inhabit them, such as amphibians and reptiles. Semi-arid regions are often thought to have lower biodiversity and thus have been overlooked, resulting in the underestimation of their biological richness. Therefore, the aim of this study was to conduct an inventory of amphibians and reptiles in the semi-arid municipality of...

  1. Competitive Promoter-Associated Matrix Attachment Region Binding of the Arid3a and Cux1 Transcription Factors

    Directory of Open Access Journals (Sweden)

    Dongkyoon Kim

    2017-12-01

    Full Text Available Arid3a/Bright/Dril1 is a B cell-specific transactivator that regulates immunoglobulin heavy chain (IgH gene transcription by binding promoter and enhancer-associated matrix attachment regions (MARs within the IgH gene locus. Promoter MAR-mediated Arid3a transactivation is antagonized by direct competition of MAR binding by Cux1/CDP—a ubiquitously expressed repressor originally termed NF-μNR. We report that the NF-μNR complex includes Arid3a in B cells but not in non-B cells through mobility shift assays. The binding activity of NF-μNR and Arid3a in B cells is reciprocally altered during the cell division cycle and by the B cell mitogen lipopolysaccharide LPS. LPS treatment had no effect on Arid3a localization but increased its total abundance within the nucleus and cytoplasm. We show that this increased level of Arid3a is capable of displacing Cux from the MARs to facilitate IgH gene transcription. Finally, we showed that the MARs (termed Bf150 and Tx125 associated with the VH1 rearranged variable region expressed in the S107 murine plasmacytoma, can repress reporter gene transcription in non-B cells and that they can relieve the repression mediated by Eμ enhancer in B cells. These results have significant implications for early human development and demonstrate that MARs in IgH locus, NF-µNR and Arid3a regulate IgH gene expression in a concerted fashion. This paves the way for future studies examining the misregulation of this pathway in pediatric disease.

  2. Mining influence on underground water resources in arid and semiarid regions

    Science.gov (United States)

    Luo, A. K.; Hou, Y.; Hu, X. Y.

    2018-02-01

    Coordinated mining of coal and water resources in arid and semiarid regions has traditionally become a focus issue. The research takes Energy and Chemical Base in Northern Shaanxi as an example, and conducts statistical analysis on coal yield and drainage volume from several large-scale mines in the mining area. Meanwhile, research determines average water volume per ton coal, and calculates four typical years’ drainage volume in different mining intensity. Then during mining drainage, with the combination of precipitation observation data in recent two decades and water level data from observation well, the calculation of groundwater table, precipitation infiltration recharge, and evaporation capacity are performed. Moreover, the research analyzes the transforming relationship between surface water, mine water, and groundwater. The result shows that the main reason for reduction of water resources quantity and transforming relationship between surface water, groundwater, and mine water is massive mine drainage, which is caused by large-scale coal mining in the research area.

  3. Hydrothermal pretreatment and enzymatic hydrolysis of mixed green and woody lignocellulosics from arid regions

    DEFF Research Database (Denmark)

    Ashraf, Muhammad Tahir; Thomsen, Mette Hedegaard; Schmidt, Jens Ejbye

    2017-01-01

    Utilization of multi-specie feedstocks is imperative for application of lignocellulosic biorefineries in arid regions. Different lignocellulosic residues vary in composition and anatomical features. Pretreatment and enzymatic hydrolysis are two processes at the front end of any lignocellulosics...... biorefinery applying biochemical pathway, and have to efficiently deal with the variance in the feedstock composition and properties. However, there is limited knowledge about effect of mixing different lignocellulosics on pretreatment and enzymatic hydrolysis yields. In this study effect of mixing...... on the yields from hydrothermal pretreatment and enzymatic hydrolysis was analyzed by mixing three different lignocellulosic residues — Bermuda grass, Jasmine hedges, and date palm fronds. Results showed that the individual and the mixed lignocellulosics gave same yields when treated under similar conditions...

  4. Estimation of hourly ultraviolet solar irradiance in the semi-arid northeast region of Brasil

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Ricardo C. de; Tiba, Chigueru [Dept. de Energia Nuclear da Univ. Federal de Pernambuco, Recife, Pernambuco (Brazil)

    2008-07-01

    Two computational codes, SPCTRAL2 and SMARTS2, were used for estimating ultraviolet solar irradiance in a locality of the semi-arid region of the Northeast of Brazil. The softwares presented simplicity of use, precision and relative ease in obtaining the input variables: zenith angle, atmospheric pressure in relation to sea level, relative humidity of the air, amount of precipitable water, total ozone and the aerosol optic depths (AOD). All these variables are measured in conventional meteorological stations, except for the aerosol optic depth. The AOD was measured with an apparatus that was constructed with a narrow band LED sensor, centered in 555nm which measures the monochromatic radiation transmission through the terrestrial atmosphere, which can be described by Beer's law. The measurements for obtaining the AOD were carried out during the months of December, 2006 and January, 2007 for Pesqueira-PE (Longitude -36.77 and Latitude 8.4 ) semi-arid region of Pernambuco, at intervals of 10 and 10 minutes, simultaneously. The ultraviolet solar irradiation was measured with a TURV (Total Ultraviolet Radiometer) Eppley Pyranometer on a minute scale. The computational simulations with SPCTRAL2 and SMARTS2 were made considering the following cases: (a) obtention of daily AOD, or be it, coming from the linear extrapolation of all the data along the day (b) obtention of hourly AOD, or be it the linearization by parts (piecewise). In the first case, the results of the simulations of ultraviolet solar irradiance and ultraviolet radiation index show an error of 4% and 13% for solar midday, and 78% at end of afternoon, when compared with the values measured with the TURV pyranometer. These results were significantly improved when using the AOD obtained on hourly bases: an error of 6.7 % for solar midday, a maximum error of 10% between 11 and 13 h, a maximum error of 20% between 10 and 14h and finally a maximum error of 30% between 9 and 15h. (orig.)

  5. [Effect of Biochar on Soil Greenhouse Gas Emissions in Semi-arid Region].

    Science.gov (United States)

    Guo, Yan-liang; Wang, Dan-dan; Zheng, Ji-yong; Zhao, Shi-wei; Zhang, Xing-chang

    2015-09-01

    This study aimed to investigate the effects of biochar addition on the emission of greenhouse gases from farmland soil in semi-arid region. Through an in-situ experiments, the influence of sawdust biochar(J) and locust tree skin biochar (H) at three doses (1%, 3%, and 5% of quality percentage) on C2, CH4 and N2O emissions were studied within the six months in the south of Ningxiaprovince. The results indicated that soil CO2 emission flux was slightly increased with the addition doses for both biochars, and the averaged CO2 emission flux for sawdust and locust tree skin biochar was enhanced by 1. 89% and 3. 34% compared to the control, but the difference between treatments was not statistically significant. The soil CH4 emission was decreased with the increasing of biochar doses, by 1. 17%, 2. 55%, 4. 32% for J1, J3, J5 and 2. 35%, 5. 83%, 7. 32% for H1, H3, H5, respectively. However, the difference was statistically significant only for J5, H3 and H5 treatments (P effect on soil N2O emission. Our study indicated that the biochar has no significant influence on soil CO2 and N2O emissions within six months in semi-arid region and can significantly influence soil CH4 emissions (P < 0. 05). As for biochar type, the locust tree skin biochar is significantly better than the sawdust biochar in terms of restraining CH4 emission(P = 0. 048).

  6. Towards a physically-based multi-scale ecohydrological simulator for semi-arid regions

    Science.gov (United States)

    Caviedes-Voullième, Daniel; Josefik, Zoltan; Hinz, Christoph

    2017-04-01

    The use of numerical models as tools for describing and understanding complex ecohydrological systems has enabled to test hypothesis and propose fundamental, process-based explanations of the system system behaviour as a whole as well as its internal dynamics. Reaction-diffusion equations have been used to describe and generate organized pattern such as bands, spots, and labyrinths using simple feedback mechanisms and boundary conditions. Alternatively, pattern-matching cellular automaton models have been used to generate vegetation self-organization in arid and semi-arid regions also using simple description of surface hydrological processes. A key question is: How much physical realism is needed in order to adequately capture the pattern formation processes in semi-arid regions while reliably representing the water balance dynamics at the relevant time scales? In fact, redistribution of water by surface runoff at the hillslope scale occurs at temporal resolution of minutes while the vegetation development requires much lower temporal resolution and longer times spans. This generates a fundamental spatio-temporal multi-scale problem to be solved, for which high resolution rainfall and surface topography are required. Accordingly, the objective of this contribution is to provide proof-of-concept that governing processes can be described numerically at those multiple scales. The requirements for a simulating ecohydrological processes and pattern formation with increased physical realism are, amongst others: i. high resolution rainfall that adequately captures the triggers of growth as vegetation dynamics of arid regions respond as pulsed systems. ii. complex, natural topography in order to accurately model drainage patterns, as surface water redistribution is highly sensitive to topographic features. iii. microtopography and hydraulic roughness, as small scale variations do impact on large scale hillslope behaviour iv. moisture dependent infiltration as temporal

  7. Development of urbanization in arid and semi arid regions based on the water resource carrying capacity -- a case study of Changji, Xinjiang

    Science.gov (United States)

    Xiao, H.; Zhang, L.; Chai, Z.

    2017-07-01

    The arid and semiarid region in China where have a relatively weak economic foundation, independent development capacity, and the low-level of urbanization. The new urbanization within these regions is facing severe challenges brought by the constraints of resources. In this paper, we selected the Changji Hui Autonomous Prefecture, Xinjiang Uyghur Autonomous Region as study area. We found that agricultural planting structure is the key water consumption index based on the research about the main water demands of domestic, agriculture and industry. Finally, we suggest that more attentions should be paid to the rational utilization of water resources, population carrying capacity, and adjust and upgrade the industrial structure, with the purpose of coordination with the Silk Road Economic Belt.

  8. Water use and the thermoregulatory behaviour of kangaroos in arid regions: insights into the colonisation of arid rangelands in Australia by the Eastern Grey Kangaroo (Macropus giganteus).

    Science.gov (United States)

    Dawson, Terence J; McTavish, Kirsten J; Munn, Adam J; Holloway, Joanne

    2006-01-01

    The Eastern Grey Kangaroo (Macropus giganteus) occurs mostly in the wetter regions of eastern Australia. However, in the past 30-40 years it has moved into more arid regions (rainfall Kangaroo (Macropus rufus). An increased access to water (supplied for domestic stock) may explain this range extension, but changes in the availability of preferred feed could also be involved. The water use, drinking patterns and thermoregulatory behaviour of these two species of kangaroo have been examined in a semi-free range study, during summer at an arid rangeland site. Foraging was largely nocturnal in both species and during the day they behaved to reduce heat loads. This was especially so for M. giganteus, which showed greater shade seeking. However, it still used more water (72 +/- 2.6 mL kg(-1) day(-1), mean +/- SE) than M. rufus (56 +/- 7.6 mL kg(-1) day(-1)) and drank twice as frequently. Although M. giganteus produced a less concentrated urine (1422 +/- 36 mosmol kg(-1)) than M. rufus (1843 +/- 28 mosmol kg(-1)), kidney physiology did not explain all of the differences in water metabolism between the species. Water from the feed and faecal water retention also appear to be involved. Broadly, a better access to reliable water and the utilisation of mesic microhabitats has enabled M. giganteus to make inroads into the changing rangelands of eastern Australia. However, changes in the vegetation, due to stock grazing, have also favoured M. giganteus, which is a grass eating specialist.

  9. Runoff and sediment transport in the arid regions of Argentina and India - a case study in comparative hydrology

    NARCIS (Netherlands)

    Sharma, K.D.; Menenti, M.; Huygen, J.; Fernandez, P.C.; Vich, A.

    1996-01-01

    The arid zones of Argentina and India have been compared. In both regions run-off is often generated by the Hortonian infiltration surplus overland flow, and run-off response to precipitation input tends to be rapid. The sediment transport is governedby the transport capacity of run-off rather than

  10. Regional integrated modelling of climate change impacts on natural resources and resource usage in semi-arid Norhteast Brazil

    NARCIS (Netherlands)

    Krol, Martinus S.; Bronstert, Axel

    2007-01-01

    Semi-arid regions are characterised by a high vulnerability of natural resources to climate change, pronounced climatic variability and often by water scarcity and related social stress. The analysis of the dynamics of natural conditions and the assessment of possible strategies to cope with

  11. Tillage and residue effects on rainfed wheat and corn production in the Semi-Arid Regions of Northern China

    NARCIS (Netherlands)

    Wang, X.B.; Hoogmoed, W.B.; Perdok, U.D.; Cai, D.X.

    2003-01-01

    Field studies on tillage and residue management for spring corn were conducted at two sites, in Tunliu (1987-1990), and Shouyang (1992-1995) counties of Shanxi province in the semihumid arid regions of northern China. This paper discusses the effects of different fall tillage (winter fallow tillage)

  12. Observations of the atmospheric boundary layer height over Abu Dhabi, United Arab Emirates: Investigating boundary layer climatology in arid regions

    Science.gov (United States)

    Marzooqi, Mohamed Al; Basha, Ghouse; Ouarda, Taha B. M. J.; Armstrong, Peter; Molini, Annalisa

    2014-05-01

    Strong sensible heat fluxes and deep turbulent mixing - together with marked dustiness and a low substrate water content - represent a characteristic signature in the boundary layer over hot deserts, resulting in "thicker" mixing layers and peculiar optical properties. Beside these main features however, desert ABLs present extremely complex local structures that have been scarcely addressed in the literature, and whose understanding is essential in modeling processes such as the transport of dust and pollutants, and turbulent fluxes of momentum, heat and water vapor in hyper-arid regions. In this study, we analyze a continuous record of observations of the atmospheric boundary layer (ABL) height from a single lens LiDAR ceilometer operated at Masdar Institute Field Station (24.4oN, 54.6o E, Abu Dhabi, United Arab Emirates), starting March 2013. We compare different methods for the estimation of the ABL height from Ceilometer data such as, classic variance-, gradient-, log gradient- and second derivation-methods as well as recently developed techniques such as the Bayesian Method and Wavelet covariance transform. Our goal is to select the most suited technique for describing the climatology of the ABL in desert environments. Comparison of our results with radiosonde observations collected at the nearby airport of Abu Dhabi indicate that the WCT and the Bayesian method are the most suitable tools to accurately identify the ABL height in all weather conditions. These two methods are used for the definition of diurnal and seasonal climatologies of the boundary layer conditional to different atmospheric stability classes.

  13. Spatiotemporal characterization of dissolved carbon for inland waters in semi-humid/semi-arid region, China

    Directory of Open Access Journals (Sweden)

    K. S. Song

    2013-10-01

    Full Text Available Spatiotemporal variations of dissolved organic carbon (DOC and inorganic carbon (DIC in 26 waters across the semi-humid/semi-arid Songnen Plain, China, were examined with data collected during 2008–2011. Fresh (n = 14 and brackish (n = 12 waters were grouped according to electrical conductivity (threshold = 1000 μS cm−1 Significant differences in the average DOC and DIC concentrations were observed between the fresh (5.63 mg L−1, 37.39 mg L−1 and the brackish waters (15.33 mg L−1, 142.93 mg L−1. Colored dissolved organic matter (CDOM and DOC concentrations were mainly controlled by climatic–hydrologic conditions. The investigation indicated that the outflow conditions in the semi-arid region had condensed effects on the dissolved carbon, resulting in close relationships between salinity vs. DOC (R2 = 0.66, and salinity vs. DIC (R2 = 0.94. An independent data set collected in May 2012 also confirmed this finding (DOC: R2 = 0.79, DIC: R2 = 0.91, highlighting the potential of quantifying DOC and DIC via salinity measurements for waters dispersed in the plain. Indices based on the CDOM absorption spectra (e.g., the DOC-specific CDOM absorption (SUVA254, absorption ratio a250 : a365 (E250 : E365 and the spectral slope ratio (Sr, S275−295/S350−400 were applied to characterize CDOM composition and quality. Our results indicate that high molecular weight CDOM fractions are more abundant in the fresh waters than the brackish waters.

  14. Spatiotemporal characterization of dissolved carbon for inland waters in semi-humid/semi-arid region, China

    Science.gov (United States)

    Song, K. S.; Zang, S. Y.; Zhao, Y.; Li, L.; Du, J.; Zhang, N. N.; Wang, X. D.; Shao, T. T.; Guan, Y.; Liu, L.

    2013-10-01

    Spatiotemporal variations of dissolved organic carbon (DOC) and inorganic carbon (DIC) in 26 waters across the semi-humid/semi-arid Songnen Plain, China, were examined with data collected during 2008-2011. Fresh (n = 14) and brackish (n = 12) waters were grouped according to electrical conductivity (threshold = 1000 μS cm-1) Significant differences in the average DOC and DIC concentrations were observed between the fresh (5.63 mg L-1, 37.39 mg L-1) and the brackish waters (15.33 mg L-1, 142.93 mg L-1). Colored dissolved organic matter (CDOM) and DOC concentrations were mainly controlled by climatic-hydrologic conditions. The investigation indicated that the outflow conditions in the semi-arid region had condensed effects on the dissolved carbon, resulting in close relationships between salinity vs. DOC (R2 = 0.66), and salinity vs. DIC (R2 = 0.94). An independent data set collected in May 2012 also confirmed this finding (DOC: R2 = 0.79, DIC: R2 = 0.91), highlighting the potential of quantifying DOC and DIC via salinity measurements for waters dispersed in the plain. Indices based on the CDOM absorption spectra (e.g., the DOC-specific CDOM absorption (SUVA254), absorption ratio a250 : a365 (E250 : E365) and the spectral slope ratio (Sr, S275-295/S350-400) were applied to characterize CDOM composition and quality. Our results indicate that high molecular weight CDOM fractions are more abundant in the fresh waters than the brackish waters.

  15. Study of tourists exposure rate in Mahallat hot Spring Region

    International Nuclear Information System (INIS)

    Tavakoli, H. M.B.; Fallah, M.G.; Ghiasinejad, M.

    2006-01-01

    Introduction: High level radiation areas have been recognized on various parts of the earth. Some of these areas include: Brasilia, India, and Iran. Mahallat hot spring region in the central part of Iran is also one of these areas. Study of exposure in these areas could be helpful in investigating the effects of ionizing radiation. Materials and Methods: In addition to several seasonal springs, Mahallat hot spring region contains five permanent springs named: Soleimani, Shafa, Dombe, Romatism and Sauda. Internal exposure (due to inhalation of radon gas and drinking water) and external exposure (due to cosmic rays and radioactive elements in the ground) to the tourists was studied. Used materials and apparatus include: RSS -112 ionizing chamber for environmental gamma rays exposure measurement, highly pure germanium detector for measuring radioactive elements in the ground, liquid scintillation counter for measuring 222 Rn gas concentration in water samples, Bubbler chamber and Locus cells for Rn concentration measurements (Emanation method) and Alfa guard detector for 226 Ra concentration measurements. Conclusions and Discussion: A total of 270 visitors are included in this study. Considering residual durations of the studied group in open and closed environment of bathrooms, hotel and inn rooms, obtained annual external effective dose is 75.4±8.7μSv and 138.3±11.8μSv for natives and travelers respectively. EEC coefficients has been used for calculating annual internal effective dose due to radon gas inhalation. Annual internal effective dose, in this path, is 0.9 and 2.1 mSv in open and closed environment for native and visitors respectively. Annual internal effective dose due to drinking water, is 0.43 and 0.09μSv for natives people and travelers, respectively. Measurements show that more than 90% of the received dose in the studied groups is due to radon gas inhalation. External and internal dose summation is 0.98 mSv for natives and 2.2 mSv for for

  16. Study of tourists exposure rate in Mahallat hot Spring Region

    Energy Technology Data Exchange (ETDEWEB)

    Tavakoli, H. M.B. [Isfahan Univ. of Medical Sciences, Isfahan (Iran, Islamic Republic of); Fallah, M.G. [Isfahan University of Medical Sciences (Iran, Islamic Republic of); Ghiasinejad, M. [Iran Atomic Energy Organization, Tehran (Iran, Islamic Republic of)

    2006-07-01

    Introduction: High level radiation areas have been recognized on various parts of the earth. Some of these areas include: Brasilia, India, and Iran. Mahallat hot spring region in the central part of Iran is also one of these areas. Study of exposure in these areas could be helpful in investigating the effects of ionizing radiation. Materials and Methods: In addition to several seasonal springs, Mahallat hot spring region contains five permanent springs named: Soleimani, Shafa, Dombe, Romatism and Sauda. Internal exposure (due to inhalation of radon gas and drinking water) and external exposure (due to cosmic rays and radioactive elements in the ground) to the tourists was studied. Used materials and apparatus include: RSS -112 ionizing chamber for environmental gamma rays exposure measurement, highly pure germanium detector for measuring radioactive elements in the ground, liquid scintillation counter for measuring {sup 222}Rn gas concentration in water samples, Bubbler chamber and Locus cells for Rn concentration measurements (Emanation method) and Alfa guard detector for {sup 226}Ra concentration measurements. Conclusions and Discussion: A total of 270 visitors are included in this study. Considering residual durations of the studied group in open and closed environment of bathrooms, hotel and inn rooms, obtained annual external effective dose is 75.4{+-}8.7{mu}Sv and 138.3{+-}11.8{mu}Sv for natives and travelers respectively. EEC coefficients has been used for calculating annual internal effective dose due to radon gas inhalation. Annual internal effective dose, in this path, is 0.9 and 2.1 mSv in open and closed environment for native and visitors respectively. Annual internal effective dose due to drinking water, is 0.43 and 0.09{mu}Sv for natives people and travelers, respectively. Measurements show that more than 90% of the received dose in the studied groups is due to radon gas inhalation. External and internal dose summation is 0.98 mSv for natives and 2

  17. Linear trend and abrupt changes of climate indices in the arid region of northwestern China

    Science.gov (United States)

    Wang, Huaijun; Pan, Yingping; Chen, Yaning; Ye, Zhengwei

    2017-11-01

    In recent years, climate extreme events have caused increasing direct economic and social losses in the arid region of northwestern China. Based on daily temperature and precipitation data from 1960 to 2010, this paper discussed the linear trend and abrupt changes of climate indices. The general evolution was obtained by the empirical orthogonal function (EOF), the Mann-Kendall test, and the distribution-free cumulative sum chart (CUSUM) test. The results are as follows: (1) climate showed a warming trend at annual and seasonal scale, with all temperature indices exhibiting statistically significant changes. The warm indices have increased, with 1.37%days/decade of warm days (TX90p), 0.17 °C/decade of warmest days (TXx) and 1.97 days/decade of warm spell duration indicator (WSDI), respectively. The cold indices have decreased, with - 1.89%days/decade, 0.65 °C/decade and - 0.66 days/decade for cold nights (TN10p), coldest nights (TNn) and cold spell duration indicator (CSDI), respectively. The precipitation indices have also increased significantly, coupled with the changes of magnitude (max 1-day precipitation amount (RX1day)), frequency (rain day (R0.1)), and duration (consecutive dry days (CDD)). (2) Abrupt changes of the annual regional precipitation indices and the minimum temperature indices were observed around 1986, and that of the maximum temperature indices were observed in 1996. (3) The EOF1 indicated the overall coherent distribution for the whole study area, and its principal component (PC1) was also observed, showing a significant linear trend with an abrupt change, which were in accordance with the regional observation results. EOF2 and EOF3 show contrasts between the southern and northern study areas, and between the eastern and western study areas, respectively, whereas no significant tendency was observed for their PCs. Hence, the climate indices have changed significantly, with linear trends and abrupt changes noted for all climate indices

  18. Declining agricultural production in rapidly urbanizing semi-arid regions: policy tradeoffs and sustainability indicators

    Science.gov (United States)

    Dozier, André Q.; Arabi, Mazdak; Wostoupal, Benjamin C.; Goemans, Christopher G.; Zhang, Yao; Paustian, Keith

    2017-08-01

    In rapidly urbanizing semi-arid regions, increasing amounts of historically irrigated cropland lies permanently fallowed due to water court policies as agricultural water rights are voluntarily being sold to growing cities. This study develops an integrative framework for assessing the effects of population growth and land use change on agricultural production and evaluating viability of alternative management strategies, including alternative agricultural transfer methods, regional water ownership restrictions, and urban conservation. A partial equilibrium model of a spatially-diverse regional water rights market is built in application of the framework to an exemplary basin. The model represents agricultural producers as profit-maximizing suppliers and municipalities as cost-minimizing consumers of water rights. Results indicate that selling an agricultural water right today is worth up to two times more than 40 years of continued production. All alternative policies that sustain agricultural cropland and crop production decrease total agricultural profitability by diminishing water rights sales revenue, but in doing so, they also decrease municipal water acquisition costs. Defining good indicators and incorporating adequate spatial and temporal detail are critical to properly analyzing policy impacts. To best improve agricultural profit from production and sale of crops, short-term solutions include alternative agricultural transfer methods while long-term solutions incorporate urban conservation.

  19. [Succession pattern of artificial vegetation community and its ecological mechanism in an arid desert region].

    Science.gov (United States)

    Xu, Cailin; Li, Zizhen

    2003-09-01

    Focusing on the artificial vegetation protection system of the Shapotou section of Baotou-Lanzhou railway in the arid desert region of China, this paper examined the dynamics of dominant plant species and the succession pattern of artificial plant community in the process of establishing and developing regional artificial vegetation. It also studied the driving force and the ecologically intrinsic mechanism of the community succession. The results demonstrated that the species composition of the artificial vegetation dramatically changed after 40 years of succession, from original artificial plant community of shrub and semi-shrub to artificial-natural desert plant community with annual herb dominated. During the process of succession, the importance values of artificial shrubs, such as Caragana korshinskii and Hedysarum scoparius, decreased and gradually retreated from the artificial plant community, while the naturally multiplied annual herb, such as Eragrostis poaeoides, Bassia dasyphylla, Salsola ruthenica, Chloris virgata and etc., were presented one after another and gradually became dominant. Besides, Artemisia ordosica always played a key role in the community due to its ability of naturally sowing and self-replacement. This type of succession pattern was closely related to the shortage of precipitation resource in this region and the formation of soil crust which inhibited the reproduction of shrub and perennial herb with deep root systems. This study provided a theoretical ground for realizing persistent development of artificial plant community.

  20. Mechanisms, timing and quantities of recharge to groundwater in semi-arid and tropical regions

    International Nuclear Information System (INIS)

    Edmunds, W.M.

    2001-01-01

    Groundwater being exploited in many and and semi-arid regions at the present day was recharged during former humid episodes of the Pleistocene or Holocene and, in contrast, the amounts derived from modem recharge are small generally small and variable. Geochemical and isotopic techniques provide the most effective way to calculate modem recharge and to investigate recharge history, since physically- based water-balance methods are generally inapplicable in semiarid regions. Examples from Africa (Senegal, Niger, Nigeria, Sudan as well as Cyprus) show that direct recharge rates may vary from zero to around 40% of mean rainfall, dependent primarily on the soil depth and the lithology. Spatial variability presents a real problem in any recharge investigation but results from Senegal show that unsaturated zone profiles may be extrapolated using the chemistry of shallow groundwater. Unsaturated-zone studies show that there are limiting conditions to direct recharge through soil, but that present day replenishment of aquifers takes place via wadis and channels. In the Butana area of central Sudan the regional groundwater was also recharged during a mid-Holocene wet phase and is now in decline. The only current recharge sources, which can be recognised distinctly using stable isotopes, are Nile baseflow and ephemeral wadi floods. (author)

  1. Physiological and productive responses of multiparous lactating Holstein cows exposed to short-term cooling during severe summer conditions in an arid region of Mexico

    Science.gov (United States)

    Avendaño-Reyes, L.; Hernández-Rivera, J. A.; Álvarez-Valenzuela, F. D.; Macías-Cruz, U.; Díaz-Molina, R.; Correa-Calderón, A.; Robinson, P. H.; Fadel, J. G.

    2012-11-01

    Heat stress generates a significant economic impact for the dairy industry in arid and semi-arid regions of the world, so that heat abatement is an important issue for dairy producers. The objective of this study was to evaluate effects of two short-term cooling periods on physiological and productive status of lactating Holstein cows during hot ambient temperatures. Thirty-nine multiparous cows were blocked by milk yield and assigned to one of three treatments including: control group (C), cows cooled before milking time (0500 and 1700 h daily, 1 h cooling); AM group, cows cooled at 1000 h and before milking (2 h cooling); and AM + PM group, cows cooled at 1100, 1500 and 2200 h, as well as before milking (4 h cooling). The cooling system was placed in the holding pen which the cows were moved through for cooling. Respiratory rate, and temperatures of thurl and right flank, were lower ( P cows from the AM + PM group than AM and C cows during the morning and afternoon. However, udder temperature was higher in the AM + PM group compared to AM and C groups during the afternoon, although lower than the AM group during the morning. Rectal temperature was similar in all groups. Thyroxin concentrations tended ( P cows had a trend ( P cows.

  2. Productivity of selected plant species adapted to arid regions. [Crassulacean metabolizing plants; Agave deserti and Ferocactus acanthodes

    Energy Technology Data Exchange (ETDEWEB)

    Nobel, P.S.

    1980-01-01

    The biomass potential of selected arid region species for alcohol production merits careful consideration. The basis for this interest is the current low agronomic use of arid lands and the potential productivity of certain species adapted to these lands. Plants displaying Crassulacean acid metabolism (CAM) are particularly interesting with reference to biomass for fuel in regions with low rainfall, because plants with this photosynthetic process are strikingly efficient in water requirements. For CAM plants, CO/sub 2/ fixation occurs primarily at night, when tissue surface temperature and hence transpirational water loss is less than daytime values. For Agave deserti in the Sonoran desert, the water-use efficiency (mass of CO/sub 2/ fixed/mass of water transpired) over an entire year is an order of magnitude or more larger than for C-3 and C-4 plants. This indicates how well adapted CAM species are to arid regions. The potential productivity per unit land area of CAM plants is fairly substantial and, therefore, of considerable economic interest for arid areas where growth of agricultural plants is minimal.

  3. Endemic shrubs in temperate arid and semiarid regions of northern China and their potentials for rangeland restoration.

    Science.gov (United States)

    Chu, Jianmin; Yang, Hongxiao; Lu, Qi; Zhang, Xiaoyan

    2015-06-03

    Some endemic shrubs in arid and semiarid ecosystems are in danger of extinction, and yet they can play useful roles in maintaining or restoring these ecosystems, thus practical efforts are needed to conserve them. The shrubs Amygdalus pedunculata Pall., Amygdalus mongolica (Maxim.) Ricker and Ammopiptanthus mongolicus (Maxim. ex Kom.) Cheng f. are endemic species in arid and semiarid regions of northern China, where rangeland desertification is pronounced due to chronic overgrazing. In this study, we tested the hypothesis that these endemic shrubs have developed adaptations to arid and semiarid environments and could play critical roles as nurse species to initiate the process of rangeland recovery. Based on careful vegetation surveys, we analysed the niches of these species in relation to precipitation, temperature and habitats. All sampling plots were categorized by these endemics and sorted by the non-metric multidimensional scaling method. Species ratios of each life form and species co-occurrence rates with the endemics were also evaluated. Annual average temperature and annual precipitation were found to be the key factors determining vegetation diversity and distributions. Amygdalus pedunculata prefers low hills and sandy land in temperate semiarid regions. Amygdalus mongolica prefers gravel deserts of temperate semiarid regions. Ammopiptanthus mongolicus prefers sandy land of temperate arid regions. Communities of A. pedunculata have the highest diversity and the largest ratios of long-lived grass species, whereas those of A. mongolicus have the lowest diversity but the largest ratios of shrub species. Communities of A. mongolica are a transition between the first two community types. These findings demonstrate that our focal endemic shrubs have evolved adaptations to arid and semiarid conditions, thus they can be nurse plants to stabilize sand ground for vegetation restoration. We suggest that land managers begin using these shrub species to restore

  4. Hot Spots and Hot Times: Wildlife Road Mortality in a Regional Conservation Corridor

    Science.gov (United States)

    Garrah, Evelyn; Danby, Ryan K.; Eberhardt, Ewen; Cunnington, Glenn M.; Mitchell, Scott

    2015-10-01

    Strategies to reduce wildlife road mortality have become a significant component of many conservation efforts. However, their success depends on knowledge of the temporal and spatial patterns of mortality. We studied these patterns along the 1000 Islands Parkway in Ontario, Canada, a 37 km road that runs adjacent to the St. Lawrence River and bisects the Algonquin-to-Adirondacks international conservation corridor. Characteristics of all vertebrate road kill were recorded during 209 bicycle surveys conducted from 2008 to 2011. We estimate that over 16,700 vertebrates are killed on the road from April to October each year; most are amphibians, but high numbers of birds, mammals, and reptiles were also found, including six reptiles considered at-risk in Canada. Regression tree analysis was used to assess the importance of seasonality, weather, and traffic on road kill magnitude. All taxa except mammals exhibited distinct temporal peaks corresponding to phases in annual life cycles. Variations in weather and traffic were only important outside these peak times. Getis-Ord analysis was used to identify spatial clusters of mortality. Hot spots were found in all years for all taxa, but locations varied annually. A significant spatial association was found between multiyear hot spots and wetlands. The results underscore the notion that multi-species conservation efforts must account for differences in the seasonality of road mortality among species and that multiple years of data are necessary to identify locations where the greatest conservation good can be achieved. This information can be used to inform mitigation strategies with implications for conservation at regional scales.

  5. Genetic resistance to natural coccidiosis infection in goats in a semi-arid region of India

    Directory of Open Access Journals (Sweden)

    P.K. Rout

    2015-12-01

    Full Text Available Coccidiosis is one of the major causes of kid mortality in tropical regions and causes significant loss to farmers by affecting growth and feed efficiency in the growing kid. The strategy to control the coccidiosis is mainly through drug usage and is not efficacious at present. Therefore, an alternative strategy is required to control the disease in goats. Increasing genetic resistance to coccidiosis may be an appropriate complementary control strategy. The purpose of this study was to analyse the genetic variation in severity of natural coccidiosis infections in kids in the semi-arid region. The observations were recorded in 227 kids of Barbari and Jamunapari goats. Barbari goats had higher mean faecal oocyst counts (FOC than Jamunapari goats at 3 and 6 months of age. The heritability for FOC was 0.05 and 0.15 at 3 and 6 months of age, respectively. All phenotypic and environmental correlations between FOC and live weight traits were low and negative, indicating a tendency for more heavily infected kids in the flock to grow more slowly. Genetic correlations were largely similar, but had large standard errors. The results suggest that genetic resistance control strategy can potentially be useful for the better performance in the existing managemental condition.

  6. An ecological engineering approach for keeping water from reaching interred wastes in arid or semiarid regions

    International Nuclear Information System (INIS)

    Anderson, J.E.

    1997-01-01

    This paper describes application of a soil-plant cover system (SPCS) to preclude water from reaching interred wastes in arid and semiarid regions. Where potential evapotranspiration far exceeds precipitation, water can be kept from reaching buried wastes by (1) providing a sufficiently deep cap of soil to store precipitation that falls while plants are dormant and (2) maintaining plant cover to deplete soil moisture during the growing season, thereby emptying the storage reservoir. Research at the Idaho National Engineering Laboratory (INEL) has shown that 2 m of soil is adequate to store moisture from snowmelt and spring rains. Healthy stands of perennial grasses and shrubs adapted to the INEL climate use all available soil moisture, even during a very wet growing season. However, burrowing by small mammals or ants may affect the performance of a SPCS by increasing infiltration of water. Intrusion barriers of gravel and cobble can be used to restrict burrowing, but emplacement of such barriers affects soil moisture storage and plant rooting depths. A replicated field experiment to investigate the implications of those effects is in progress. Incorporation of an SPCS should be considered in the design of isolation barriers for shallow land burial of hazardous wastes in and regions

  7. Radioecological characterization of a uranium mining site located in a semi-arid region in Brazil

    International Nuclear Information System (INIS)

    Fernandes, Horst M.; Lamego Simoes Filho, F. Fernando; Perez, Valeska; Franklin, Mariza Ramalho; Gomiero, Luiz Alberto

    2006-01-01

    The work presents the radioecological characterization of the new Brazilian uranium mining and milling site located in a semi-arid region of the country. The process characterization demonstrated that in heap leach plants most of the 226 Ra remains in the leached ore. Despite the potential higher availability of radium isotopes in the soils of the studied region the lack of precipitation in that area reduces the leaching/mobilization of the radionuclides. High 226 Ra and 228 Ra concentrations were found in manioc while 21 Pb was significant in pasture. It was suggested that a range from 10 -3 to 10 -1 may conveniently encompass most of the transfer factors (TF) values for soil/plant systems (i.e. involving different cultures, different soils and natural radionuclides). Impacts due to aerial transportation of aerosols and radon generated in the mining were proved to be minimal and restricted to an area not greater than 15 km 2 . Finally, uranium complexation by carbonates was shown to be the main mechanism responding for the elevated radionuclide concentration in groundwater

  8. Bacterial Diversity within the Extreme Arid Atacama Desert Soils of the Yungay Region, Chile

    Science.gov (United States)

    Connon, S. A.; Lester, E. D.; Shafaat, H. S.; Obenhuber, D. C.; Ponce, A.

    2006-12-01

    Surface and subsurface soil samples analyzed for this study were collected from the hyper-arid Yungay region of the Atacama Desert, Chile. This is the first report of microbial diversity from DNA extracted directly from these extremely desiccated soils. Our data shows that 94% of the 16S rRNA genes cloned from these soils belong to the Actinobacteria phylum. A 24-hour time course series showed a diurnal water activity (aw) cycle that peaked at 0.52 in the early predawn hours, and ranged from 0.08 0.01 during the day. All measured water activity values were below the level required for microbial growth or enzyme activity. Total organic carbon (TOC) levels in this region were just above the limits of detection and ranged from 220 660 μg/g of soil. Phospholipid fatty acid (PLFA) levels indicated cellular biomass ranging from 2 ×105 to 7 ×106 cell equivalents per gram of soil. The culturable counts were low with most samples showing no growth on standard plates of R2A medium; the highest single count was 47 colony forming units (CFU) per gram.

  9. Leaf anatomy of six species of Heliotropiaceae Schrad. from the Brazilian semi-arid region

    Directory of Open Access Journals (Sweden)

    Elisabeth Emília Augusta Dantas Tölke

    2015-09-01

    Full Text Available The family Heliotropiaceae has more than 450 species, mainly distributed in the tropics and subtropics. In Brazil, it is represented by the genera Euploca Nutt., Heliotropium L., Myriopus Small and Tournefortia L. The aim of this study was to describe the leaf anatomy of six species of Heliotropiaceae recorded in the semi-arid region of Brazil: E. polyphylla (Lehm. J.I.M. Melo & Semir, E. procumbens (Mill. Diane & Hilger, H. angiospermum Murray, H. curassavicum L., M. rubicundus (Salzm. ex DC. Luebert and M. salzmannii (DC. Diane & Hilger. Besides contributing to the knowledge of the anatomy of the representatives of the family in the Caatinga (Brazilian savannah, we also sought to determine and highlight the anatomical features adaptive to the region and to identify features with potential diagnostic value. Leaf structures were analyzed by light microscopy and scanning electron microscopy. Additional tests were also carried out to detect starch and total lipids. The morphological variation and the distribution of trichomes were the most relevant features for species diagnosis. The distribution of stomata in M. salzmannii and H. angiospermum differed from that described in other papers, which demonstrates the anatomical plasticity of these species. This is the first report describing the leaf blade of M. rubicundus.

  10. Leaf anatomy of six species of Heliotropiaceae Schrad. from the Brazilian semi-arid region

    Directory of Open Access Journals (Sweden)

    Elisabeth Tölke

    2015-06-01

    Full Text Available http://dx.doi.org/10.5007/2175-7925.2015v28n3p1 The family Heliotropiaceae has more than 450 species, mainly distributed in the tropics and subtropics. In Brazil, it is represented by the genera Euploca Nutt., Heliotropium L., Myriopus Small and Tournefortia L. The aim of this study was to describe the leaf anatomy of six species of Heliotropiaceae recorded in the semi-arid region of Brazil: E. polyphylla (Lehm. J.I.M. Melo & Semir, E. procumbens (Mill. Diane & Hilger, H. angiospermum Murray, H. curassavicum L., M. rubicundus (Salzm. ex DC. Luebert and M. salzmannii (DC. Diane & Hilger. Besides contributing to the knowledge of the anatomy of the representatives of the family in the Caatinga (Brazilian savannah, we also sought to determine and highlight the anatomical features adaptive to the region and to identify features with potential diagnostic value. Leaf structures were analyzed by light microscopy and scanning electron microscopy. Additional tests were also carried out to detect starch and total lipids. The morphological variation and the distribution of trichomes were the most relevant features for species diagnosis. The distribution of stomata in M. salzmannii and H. angiospermum differed from that described in other papers, which demonstrates the anatomical plasticity of these species. This is the first report describing the leaf blade of M. rubicundus.

  11. Environmental Effects of Irrigation in Arid and Semi-Arid Regions Efectos Ambientales del Riego en Regiones Áridas y Semi-Áridas en América Latina

    Directory of Open Access Journals (Sweden)

    Alicia Fernández Cirelli

    2009-12-01

    Full Text Available This article reviews the state of the art with respect to the environmental effects of irrigated agriculture on water and soil quality in arid and semi-arid regions on a field scale. Information is scarce and fragmentary. Examples in selected areas of other arid and semi-arid regions in the world clearly show the importance of studying the environmental impact of irrigation practices on water and soil quality. Studies mainly refer to waterlogging and salinization. As regards agrochemicals, fertilizers have been taken into account through nitrate leaching. The impact of micropollutants such as pesticides and heavy metals on water and soil quality is studied mainly by modeling. Pharmaceutical compounds emerge as pollutants when wastewater is used for irrigation without any previous treatment, situation which is now the object of new studies. There is an obvious need to study in-depth knowledge related to appropriate technologies for the use, treatment, and reuse of wastewater which is a valuable resource in arid and semi-arid regions.En este trabajo se presenta una revisión del estado del arte relativo a los efectos ambientales de la agricultura bajo riego en la calidad del agua y de los suelos en regiones semiáridas y áridas de América Latina a escala de campo. La información relevada es escasa y fragmentaria. Ejemplos en áreas seleccionadas de otras regiones del mundo muestran claramente la importancia del estudio del impacto ambiental de las prácticas de riego en la calidad de agua y del suelo. La mayor parte de los estudios se refieren a anegamiento y salinización de suelos. En relación a los agroquímicos, los fertilizantes han recibido mayor atención, en particular considerando la lixiviación de nitratos. El impacto de los microcontaminantes, como los pesticidas o los metales pesados, se ha estudiado mayormente a través de la aplicación de modelos. Los compuestos farmacéuticos surgen como contaminantes cuando las aguas servidas

  12. New Approaches for Responsible Management of Offshore Springs in Semi-arid Regions

    Science.gov (United States)

    Shaban, Amin; de Jong, Carmen; Al-Sulaimani, Zaher

    2017-04-01

    In arid and semi-arid regions, such as the Mediterranean and Gulf Region where water is scarce water demand has been exacerbated and become a major environmental challenge. Presently there is massive pressure to develop new water sources to alleviate existing water stress. In the quest for more freshwater even groundwater discharge into the sea in the form of "off-shore freshwater springs" (or submarine groundwater discharge) has been contemplated as a potential source of unconventional water in coastal zones. Offshore-springs are derived from aquifers with complex geological controls mainly in the form of faults and karst conduits. Representing a border-line discipline, they have been poorly studied with only few submarine groundwater monitoring sites existing worldwide. Recently, innovative techniques have been developed enabling springs to be detected via remote sensing such as airborne surveys or satellite images. "Thermal Anomalies" can be clearly identified as evidence for groundwater discharge into the marine environment. A diversity of groundwater routes along which off-shore springs are fed from land sources can be recognized and near-shore and offshore springs differentiated and classified according to their geometry. This is well pronounced along the coast of Lebanon and offshore of Oman. Offshore springs play an important role in the marine ecosystem as natural sources of mercury, metals, nutrients, dissolved carbon species and in cooling or warming ocean water. However, they are extremely sensitive to variations in qualitative and quantitative water inputs triggered by climate change and anthropogenic impacts especially in their recharge zones. Pollutants such as sewage, detergents, heavy metals or herbicides that negatively affect water quality of offshore springs can transit the groundwater rapidly. Recently these springs have also been severely affected by uncontrolled water abstraction from land aquifers. In Bahrain, overpumping combined with

  13. Ecosystem Services Evaluation and Its Spatial Characteristics in Central Asia’s Arid Regions: A Case Study in Altay Prefecture, China

    Directory of Open Access Journals (Sweden)

    Qi Fu

    2015-06-01

    Full Text Available Ecosystem services are important foundations to realize the sustainable development of economy and society. The question of how to quantitatively evaluate ecosystem services in a scientific way is a hot topic among international researchers. Studying the spatial characteristics of ecosystem services in arid regions can provide the theoretical and practical basis for coordinating a sustainable man-land relationship. Altay Prefecture of China, a typical arid region in Central Asia, was taken as the study area. It is on the Silk Road economic belt, which is a key region in the program of developing Western China. Three ecosystem services: water yield, soil conservation, and net primary productivity were quantitatively evaluated. The results show that (1 the spatial distribution pattern has a distinct characteristic of zonality; (2 mountain zone and mountain-oasis ecotone are the hotspots of ecosystem services; and (3 the correlation between water yield and net primary productivity shows a gradual increasing trend as altitude decreases. Objective analysis from the aspect of mechanism is given by discussing the causes of this particular pattern. It is found that altitude and slope have great influence on spatial distributions of ecosystem services, zones with the most amount of services are distributed in 1.5–2 km-altitude and 15–25°-slope. Different human activities in different regions and spatial distance decay of ecosystem services also contribute to the formation of spatial pattern. Thus, overgrazing, logging and mining are prohibited in mountain zones and mountain-oasis ecotones. Scholars are encouraged to focus on desert-ecosystem services in the future.

  14. Household carbon dioxide emissions from peasants and herdsmen in northwestern arid-alpine regions, China

    International Nuclear Information System (INIS)

    Qu, Jiansheng; Zeng, Jingjing; Li, Yan; Wang, Qin; Maraseni, Tek; Zhang, Lihua; Zhang, Zhiqiang; Clarke-Sather, Abigail

    2013-01-01

    This study assessed household CO 2 emissions (related to the consumption of necessary and luxury goods and services) of peasants and herdsmen households in arid-alpine regions in Gansu, Qinghai and Ningxia provinces, China. We also explored whether agriculture types, family income and family size have played any role in household CO 2 emissions. In order to address these issues, we: (i) developed assessment indicators for household emissions; (ii) conducted semi-structured questionnaire household surveys; and (iii) employed input-output analysis (IOA). The results showed that, the average household CO 2 emission per capita is 1.43 tons (t) CO 2 ; the proportion of subsistence emissions (related to the consumption of necessary goods and services) accounts for 93.24%, whereas luxury emissions (generated due to consumption of specific goods and services that are consumed only when household income improves) only account for 6.76%t. Moreover, household CO 2 emissions increase with family income and family size, but per capita emissions are inversely related to family size. The highest average household emissions were found in the alpine agricultural and pastoral region (6.18 t CO 2 ), followed by the irrigated agricultural region (6.07 t CO 2 ) and the rain-fed agricultural region (5.34 t CO 2 ). In consideration of insignificant amount of household emissions from these poor and vulnerable groups of the society, this study suggests to follow the principle of fairness while making energy conservation, emission reduction and adaptation policies. - Highlights: ► Per capita emissions decrease as the household size increases. ► The subsistence emissions accounts for 93.24% of the total emissions. ► If heating related emissions are excluded, household emissions are negligible. ► The reduction of emissions below current levels is almost impossible. ► Poor and vulnerable groups should be given special consideration

  15. Managing saltwater intrusion in coastal arid regions and its societal implications for agriculture

    Directory of Open Access Journals (Sweden)

    J. Grundmann

    2016-05-01

    Full Text Available Coastal aquifers in arid and semiarid regions are particularly at risk due to intrusion of salty marine water. Since groundwater is predominantly used in irrigated agriculture, its excessive pumping – above the natural rate of replenishment – strengthen the intrusion process. Using this increasingly saline water for irrigation, leads to a destruction of valuable agricultural resources and the economic basis of farmers and their communities. The limitation of resources (water and soil in these regions requires a societal adaptation and change in behaviour as well as the development of appropriate management strategies for a transition towards stable and sustainable future hydrosystem states. Besides a description of the system dynamics and the spatial consequences of adaptation on the resources availability, the contribution combines results of an empirical survey with stakeholders and physically based modelling of the groundwater-agriculture hydrosystem interactions. This includes an analysis of stakeholders' (farmers and decision makers behaviour and opinions regarding several management interventions aiming on water demand and water resources management as well as the thinking of decision makers how farmers will behave. In this context, the technical counter measures to manage the saltwater intrusion by simulating different groundwater pumping strategies and scenarios are evaluated from the economic and social point of view and if the spatial variability of the aquifer's hydrogeology is taken into consideration. The study is exemplarily investigated for the south Batinah region in the Sultanate of Oman, which is affected by saltwater intrusion into a coastal aquifer system due to excessive groundwater withdrawal for irrigated agriculture.

  16. TANNIN POTENCIAL EVALUATION OF SIX FOREST SPECIES OF BRAZILIAN SEMI-ARID REGION

    Directory of Open Access Journals (Sweden)

    Juarez Benigno Paes

    2006-09-01

    Full Text Available The hide tanners of Brazil Northeast region have in Anadenanthera colubrina (Vell. Brenan var. cebil (Gris. Alts. their only source of tannins. As the activity of exploration is extractiviste without the concern of recovery of explored trees and the absence of other tannin sources, exposes the specie to exhaustion and the tanners and extractivistes family to go bankruptcy. Thus, this work aimed to evaluate the tanin potential of Prosopis juliflora, Anadenanthera colubrina var. cebil, Anacardium occidentale, Mimosa tenuiflora, Mimosa arenosa and Croton sonderianus. These species, Anacardium occidentale, Mimosa arenosa and Mimosa temuiflora showed, respectively, 19.83%, 18.11% and 17.74% of tannins. The Anadenanthera colubrina showed 11.89% and was inferior them mentioned species. The Prosopis juliflora and Croton sonderianus showed 3.02% and 6.62%, respectively. The abundance of Mimosa arenosa and Mimosa tenuiflora in the Brazilian Semi-arid proposes them as potential of tannin production. However, there is need of researches to verify their technical viability for skins, as well as for other uses for tannins.

  17. Peach response to water deficit in a semi-arid region

    Science.gov (United States)

    Paltineanu, C.; Septar, L.; Moale, C.; Nicolae, S.; Nicola, C.

    2013-09-01

    During three years a deficit irrigation experiment was performed on peach response under the semi-arid conditions of south-eastern Romania. Three sprinkler-irrigated treatments were investigated: fully irrigated, deficit irrigation treatment, and non-irrigated control treatment. Soil water content ranged between 60 and 76% of the plant available soil water capacity in fully irrigated, between 40 and 62% in deficit irrigation treatment, and between 30 and 45% in control. There were significant differences in fruit yield between the treatments. Irrigation water use efficiency was maximum in deficit irrigation treatment. Fruit yield correlated significantly with irrigation application. Total dry matter content, total solids content and titrable acidity of fruit were significantly different in the irrigated treatments vs. the control. Significant correlation coefficients were found between some fruit chemical components. For the possible future global warming conditions, when water use becomes increasingly restrictive, deficit irrigation will be a reasonable solution for water conservation in regions with similar soil and climate conditions.

  18. Soil respiration in different agricultural and natural ecosystems in an arid region.

    Directory of Open Access Journals (Sweden)

    Liming Lai

    Full Text Available The variation of different ecosystems on the terrestrial carbon balance is predicted to be large. We investigated a typical arid region with widespread saline/alkaline soils, and evaluated soil respiration of different agricultural and natural ecosystems. Soil respiration for five ecosystems together with soil temperature, soil moisture, soil pH, soil electric conductivity and soil organic carbon content were investigated in the field. Comparing with the natural ecosystems, the mean seasonal soil respiration rates of the agricultural ecosystems were 96%-386% higher and agricultural ecosystems exhibited lower CO(2 absorption by the saline/alkaline soil. Soil temperature and moisture together explained 48%, 86%, 84%, 54% and 54% of the seasonal variations of soil respiration in the five ecosystems, respectively. There was a significant negative relationship between soil respiration and soil electrical conductivity, but a weak correlation between soil respiration and soil pH or soil organic carbon content. Our results showed that soil CO(2 emissions were significantly different among different agricultural and natural ecosystems, although we caution that this was an observational, not manipulative, study. Temperature at the soil surface and electric conductivity were the main driving factors of soil respiration across the five ecosystems. Care should be taken when converting native vegetation into cropland from the point of view of greenhouse gas emissions.

  19. Soil respiration in different agricultural and natural ecosystems in an arid region.

    Science.gov (United States)

    Lai, Liming; Zhao, Xuechun; Jiang, Lianhe; Wang, Yongji; Luo, Liangguo; Zheng, Yuanrun; Chen, Xi; Rimmington, Glyn M

    2012-01-01

    The variation of different ecosystems on the terrestrial carbon balance is predicted to be large. We investigated a typical arid region with widespread saline/alkaline soils, and evaluated soil respiration of different agricultural and natural ecosystems. Soil respiration for five ecosystems together with soil temperature, soil moisture, soil pH, soil electric conductivity and soil organic carbon content were investigated in the field. Comparing with the natural ecosystems, the mean seasonal soil respiration rates of the agricultural ecosystems were 96%-386% higher and agricultural ecosystems exhibited lower CO(2) absorption by the saline/alkaline soil. Soil temperature and moisture together explained 48%, 86%, 84%, 54% and 54% of the seasonal variations of soil respiration in the five ecosystems, respectively. There was a significant negative relationship between soil respiration and soil electrical conductivity, but a weak correlation between soil respiration and soil pH or soil organic carbon content. Our results showed that soil CO(2) emissions were significantly different among different agricultural and natural ecosystems, although we caution that this was an observational, not manipulative, study. Temperature at the soil surface and electric conductivity were the main driving factors of soil respiration across the five ecosystems. Care should be taken when converting native vegetation into cropland from the point of view of greenhouse gas emissions.

  20. Cyanobacterial blooms in stratified and destratified eutrophic reservoirs in semi-arid region of Brazil.

    Science.gov (United States)

    Dantas, Enio W; Moura, Ariadne N; Bittencourt-Oliveira, Maria do Carmo

    2011-12-01

    This study investigated the dynamics of cyanobacteria in two deep, eutrophic reservoirs in a semi-arid region of Brazil during periods of stratification and destratification. Four collections were carried out at each reservoir at two depths at three-month intervals. The following abiotic variables were analyzed: water temperature, dissolved oxygen, pH, turbidity, water transparency, total phosphorus, total dissolved phosphorus, orthophosphate and total nitrogen. Phytoplankton density was quantified for the determination of the biomass of cyanobacteria. The data were analyzed using CCA. Higher mean phytoplankton biomass values (29.8 mm(3).L(-1)) occurred in the period of thermal stratification. A greater similarity in the phytoplankton communities also occurred in this period and was related to the development of cyanobacteria, mainly Cylindrospermopsis raciborskii (>3.9 mm(3).L(-1)). During the period of thermal destratification, this species co-dominated the environment with Planktothrix agardhii, Geitlerinema amphibium, Microcystis aeruginosa and Merismopedia tenuissima, as well as with diatoms and phytoflagellates. Environmental instability and competition among algae hindered the establishment of blooms more during the mixture period than during the stratification period. Thermal changes in the water column caused by climatologic events altered other physiochemical conditions of the water, leading to changes in the composition and biomass of the cyanobacterial community in tropical reservoirs.

  1. Monitoring lake level changes by altimetry in the arid region of Central Asia

    Science.gov (United States)

    Zhao, Y.; Liao, J. J.; Shen, G. Z.; Zhang, X. L.

    2017-07-01

    The study of lake level changes in arid region of Central Asia not only has important significance for the management and sustainable development of inland water resources, but also provides the basis for further study on the response of lakes to climate change and human activities. Therefore, in this paper, eleven typical lakes in Central Asia were observed. The lake edges were obtained through image interpretation using the quasi-synchronous MODIS image, and then water level information with long period (2002-2015) was acquired using ENVISAT/RA-2 and Cryosat-2 satellite borne radar altimeter data. The results show that these 11 lakes all have obvious seasonal changes of water level in a year with a high peak at different month. During 2002 - 2015, their water levels present decreased trend generally except Sarygamysh Lake, Alakol Lake and North Aral Sea. The alpine lakes are most stables, while open lakes’ levels change the most violently and closed lakes change diversely among different lakes.

  2. Animal-Based Remedies as Complementary Medicines in the Semi-Arid Region of Northeastern Brazil

    Science.gov (United States)

    Alves, Rômulo R. N.; Barbosa, José A. A.; Santos, Silene L. D. X.; Souto, Wedson M. S.; Barboza, Raynner R. D.

    2011-01-01

    Animals (and their derived products) are essential ingredients in the preparation of many traditional remedies. Despite its prevalence in traditional medical practices worldwide, research on medicinal animals has often been neglected in comparison to medicinal plant research. This work documents the medicinal animals used by a rural community in the semi-arid region, inserted in Caatinga Biome, where 66 respondents provided information on animal species used as medicine, body parts used to prepare the remedies and illnesses to which the remedies were prescribed. We calculated the informant consensus factor to determine the consensus over which species are effective for particular ailments, as well as the species use value to determine the extent of utilization of each species. We recorded the use of 51 animal species as medicines, whose products were recommended for the treatment of 68 illnesses. The informant consensus in the use of many specific remedies is fairly high, giving an additional validity to this folk medicine. Eight species not previously reported as having medicinal use were recorded. The local medicinal fauna is largely based on wild animals, including some endangered species. Given a high proportion of medicinal animals observed in the study area, it is logical to conclude that any conservation strategy should include access to modern health care. PMID:19729490

  3. New Possibilities for High-Resolution, Large-Scale Ecosystem Assessment of the World's Semi-Arid Regions

    Science.gov (United States)

    Burney, J. A.; Goldblatt, R.

    2016-12-01

    Understanding drivers of land use change - and in particular, levels of ecosystem degradation - in semi-arid regions is of critical importance because these agroecosystems (1) are home to the world's poorest populations, almost all of whom depend on agriculture for their livelihoods, (2) play a critical role in the global carbon and climate cycles, and (3) have in many cases seen dramatic changes in temperature and precipitation, relative to global averages, over the past several decades. However, assessing ecosystem health (or, conversely, degradation) presents a difficult measurement problem. Established methods are very labor intensive and rest on detailed questionnaires and field assessments. High-resolution satellite imagery has a unique role semi-arid ecosystem assessment in that it can be used for rapid (or repeated) and very simple measurements of tree and shrub density, an excellent overall indicator for dryland ecosystem health. Because trees and large shrubs are more sparse in semi-arid regions, sub-meter resolution imagery in conjunction with automated image analysis can be used to assess density differences at high spatial resolution without expensive and time-consuming ground-truthing. This could be used down to the farm level, for example, to better assess the larger-scale ecosystem impacts of different management practices, to assess compliance with REDD+ carbon offset protocols, or to evaluate implementation of conservation goals. Here we present results comparing spatial and spectral remote sensing methods for semi-arid ecosystem assessment across new data sources, using the Brazilian Sertão as an example, and the implications for large-scale use in semi-arid ecosystem science.

  4. Composition and fate of mine- and smelter-derived particles in soils of humid subtropical and hot semi-arid areas

    Energy Technology Data Exchange (ETDEWEB)

    Ettler, Vojtěch, E-mail: ettler@natur.cuni.cz [Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Praha 2 (Czech Republic); Johan, Zdenek [BRGM, Avenue Claude Guillemin, 45082 Orléans Cedex 2 (France); Kříbek, Bohdan; Veselovský, František [Czech Geological Survey, Geologická 6, 152 00 Praha 5 (Czech Republic); Mihaljevič, Martin [Institute of Geochemistry, Mineralogy and Mineral Resources, Faculty of Science, Charles University in Prague, Albertov 6, 128 43 Praha 2 (Czech Republic); Vaněk, Aleš; Penížek, Vít [Department of Soil Science and Soil Protection, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamýcká 129, 165 21 Praha 6 (Czech Republic); Majer, Vladimír [Czech Geological Survey, Geologická 6, 152 00 Praha 5 (Czech Republic); Sracek, Ondra [Department of Geology, Faculty of Science, Palacký University in Olomouc, 17. listopadu 12, 771 46 Olomouc (Czech Republic); Mapani, Ben; Kamona, Fred [Department of Geology, Faculty of Science, University of Namibia, Private Bag 13301, Windhoek (Namibia); Nyambe, Imasiku [University of Zambia, School of Mines, P. O. Box 32 379, Lusaka (Zambia)

    2016-09-01

    We studied the heavy mineral fraction, separated from mining- and smelter-affected topsoils, from both a humid subtropical area (Mufulira, Zambian Copperbelt) and a hot semi-arid area (Tsumeb, Namibia). High concentrations of metal(loid)s were detected in the studied soils: up to 1450 mg As kg{sup −1}, 8980 mg Cu kg{sup −1}, 4640 mg Pb kg{sup −1}, 2620 mg Zn kg{sup −1}. A combination of X-ray diffraction analysis (XRD), scanning electron microscopy (SEM/EDS), and electron probe microanalysis (EPMA) helped to identify the phases forming individual metal(loid)-bearing particles. Whereas spherical particles originate from the smelting and flue gas cleaning processes, angular particles have either geogenic origins or they are windblown from the mining operations and mine waste disposal sites. Sulphides from ores and mine tailings often exhibit weathering rims in contrast to smelter-derived high-temperature sulphides (chalcocite [Cu{sub 2}S], digenite [Cu{sub 9}S{sub 5}], covellite [CuS], non-stoichiometric quenched Cu–Fe–S phases). Soils from humid subtropical areas exhibit higher available concentrations of metal(loids), and higher frequencies of weathering features (especially for copper-bearing oxides such as delafossite [Cu{sup 1+} Fe{sup 3+} O{sub 2}]) are observed. In contrast, metal(loid)s are efficiently retained in semi-arid soils, where a high proportion of non-weathered smelter slag particles and low-solubility Ca–Cu–Pb arsenates occur. Our results indicate that compared to semi-arid areas (where inorganic contaminants were rather immobile in soils despite their high concentrations) a higher potential risk exists for agriculture in mine- and smelter-affected humid subtropical areas (where metal(loid) contaminants can be highly available for the uptake by crops). - Highlights: • Mining- and smelter-derived particles identified in subtropical and semi-arid soils • Sulphides, oxides, and metal-bearing arsenates most frequently encountered

  5. Modeling and Zoning Solar Energy Received at the Earth's Surface in Arid and Semiarid Regions of Central Iran

    Directory of Open Access Journals (Sweden)

    azam gholamnia

    2017-02-01

    Full Text Available Introduction: Solar radiation (Rs energy received at the Earth's surface is measured usingclimatological variables in horizontal surface and is widely used in various fields. Domination of hot and dry climates especially in the central regions of Iran results from decreasing cloudiness and precipitation and increasing sunshine hours, which shows the high potential of solar energy in Iran. There is a reasonable climatic field and solar radiation in most of regions and seasons which have provided an essential and suitable field to use and extend new and pure energy. Materials and Methods: One of the common methods to estimate the solar energy received by the earthis usingtemperature variables in any place . An empirical model is proposed to estimate the solar energy as a function of other climatic variables (maximum temperature recorded in 50 climatological, conventional stations; this model is helpful inextending the climatological solar-energy estimation in the study area. The mean values of both measured and estimated solar energy wereobjectively mapped to fill the observation gaps and reduce the noise associated with inhomogeneous statistics and estimation errors. This analysis and the solar irradiation estimation method wereapplied to 50 different climatologicalstations in Iran for monthly data during1980–2005. The main aim of this study wasto map and estimate the solar energy received in four provinces of Yazd, Esfahan, Kerman and Khorasan-e-Jonoubi.The data used in this analysis and its processing, as well as the formulation of an empirical model to estimate the climatological incident of solar energy as a function of other climatic variables, which is complemented with an objective mapping to obtain continuous solar-energy maps. Therefore, firstly the Rswasestimated using a valid model for 50 meteorological stations in which the amounts of solar radiation weren't recorded for arid and semi-arid areas in Iran. Then, the appropriate method

  6. Theoretical simulation of small scale psychometric solar water desalination system in semi-arid region

    International Nuclear Information System (INIS)

    Shatat, Mahmoud; Omer, Siddig; Gillott, Mark; Riffat, Saffa

    2013-01-01

    Many countries around the world suffer from water scarcity. This is especially true in remote and semi-arid regions in the Middle East and North Africa (MENA) where per capita water supplies decline as populations increase. This paper presents the results of a theoretical simulation of an affordable small scale solar water desalination plant using the psychometric humidification and dehumidification process coupled with an evacuated tube solar collector with an area of about 2 m 2 . A mathematical model was developed to describe the system's operation. Then a computer program using Simulink Matlab software was developed to provide the governing equations for the theoretical calculations of the humidification and dehumidification processes. The experimental and theoretical values for the total daily distillate output were found to be closely correlated. After the experimental calibration of the mathematical model, a model simulating solar radiation under the climatic conditions in the Middle East region proved that the performance of the system could be improved to produce a considerably higher amount of fresh water, namely up to 17.5 kg/m 2 day. This work suggests that utilizing the concept of humidification and dehumidification, a compact water desalination unit coupled with solar collectors would significantly increase the potable water supply in remote area. It could be a unique solution of water shortages in such areas. -- Highlights: • An affordable small scale desalination system is proposed. • A mathematical model of the desalination system is developed and programmed using Matlab Simulink. • The model describes the psychometric process based on humidification and dehumidification. • The model is used in optimal selection of elements and operating conditions for solar desalination system. • The use of solar water desalination contributes significantly to reducing global warming

  7. Achieve a Better Understanding of Cloud and Precipitation Processes for the Promotion of Water Security in Arid and Semi-Arid Regions

    Science.gov (United States)

    Farrah, S.; Al Yazidi, O.

    2016-12-01

    has been recently replaced by a new drive to solve the technical obstacles impeding its potential. There is now a real prospect that this science will come of age and play its rightful part in boosting sustainable water supplies for people at risk in arid and semi-arid regions of the world.

  8. Detection and differentiation of pollution in urban surface soils using magnetic properties in arid and semi-arid regions of northwestern China.

    Science.gov (United States)

    Wang, Bo; Xia, Dunsheng; Yu, Ye; Jia, Jia; Xu, Shujing

    2014-01-01

    Increasing urbanization and industrialization over the world has caused many social and environmental problems, one of which drawing particular concern is the soil pollution and its ecological degradation. In this study, the efficiency of magnetic methods for detecting and discriminating contaminates in the arid and semi-arid regions of northwestern China was investigated. Topsoil samples from six typical cities (i.e. Karamay, Urumqi, Lanzhou, Yinchuan, Shizuishan and Wuhai) were collected and a systematic analysis of their magnetic properties was conducted. Results indicate that the topsoil samples from the six cities were all dominated by coarse low-coercivity magnetite. In addition, the average magnetite contents in the soils from Urumqi and Lanzhou were shown to be much higher than those from Karamay, Yinchuan, Shizuishan and Wuhai, and they also have relatively higher χlf and χfd% when compared with cities in eastern China. Moreover, specific and distinctive soil pollution signals were identified at each sampling site using the combined various magnetic data, reflecting distinct sources. Industrial and traffic-derived pollution was dominant in Urumqi and Lanzhou, in Yinchuan industrial progress was observed to be important with some places affected by vehicle emission, while Karamay, Shizuishan and Wuhai were relatively clean. The magnetic properties of these latter three cities are significantly affected by both anthropogenic pollution and local parent materials from the nearby Gobi desert. The differences in magnetic properties of topsoil samples affected by mixed industrial and simplex traffic emissions are not obvious, but significant differences exist in samples affected by simplex industrial/vehicle emissions and domestic pollution. The combined magnetic analyses thus provide a sensitive and powerful tool for classifying samples according to likely sources, and may even provide a valuable diagnostic tool for discriminating among different cities

  9. Relationships between carbon fluxes and environmental factors in a drip-irrigated, film-mulched cotton field in arid region

    OpenAIRE

    Li, Xiaoyu; Liu, Lijuan; Yang, Huijin; Li, Yan

    2018-01-01

    Environmental factors and human activities play important roles in carbon fixation and emissions generated from croplands. Eddy covariance measurements in a drip-irrigated, film-mulched cotton field were used to analyze the relationships between carbon fluxes and environmental factors in Wulanwusu, northern Xinjiang, an arid region of Northwest China. Our results showed that the cumulative net carbon flux (NEE) was -304.8 g C m-2 (a strong sink) over the whole cotton growing season in 2012, w...

  10. Atmospheric Transport of Arid Aerosol from Desert Regions of Central Asia

    Science.gov (United States)

    Chen, Boris; Solomon, Paul; Sitnov, Sergei; Grechko, Evgeny; Maximenkov, Leonid; Artamonova, Maria; Pogarski, Fedor

    2010-05-01

    Investigation of atmospheric transport of arid aerosol from Central Asia was held within the ISTC project 3715. Particular attention was paid to the removal of aerosol from the Aral Sea region and its further transport, because aerosol and pollutants emission from Central Asia affect the airspace of the entire Asian continent. At the same time measurements of aerosols in the atmosphere of Central Asia are holding in a small number of stations, and currently available data are insufficient to define the initial conditions and/or verification of models of long-range transport. To identify sources of pollution transported from Central Asia, in Kyrgyzstan measurement and sampling of air were organized: at the station on the northern slope of the Kirgiz Range, 30 km south of Bishkek, at an altitude of 1700 m above sea level (Bishkek Site, 42,683N; 74,694E ), and on permanent alpine Teploklyuchenka lidar station in the Central Tien Shan at an altitude of 2000 m above sea level (Lidar Site, 42,467N; 78,533E). The chemical analysis of collected aerosol and soils samples was carried out. Measurements of aerosol at these stations have been merged with the simulation of the trajectories of air masses in the study region and with the satellite (the Terra and Aqua satellites) observations of aerosol optical thickness in this region. Satellite data for the region 43-47 N, and 58-62 E (Aral Sea) from April 2008 to September 2009 were analyzed. The moments were selected, when the value of aerosol optical thickness (AOT) was greatest (more than 0.5), and the transport from the Aral Sea region to the observation sites took place. For each of these days, the forward trajectories, which started at 6 points within the region, were calculated using the HYSPLIT model. The days, on which the trajectories reached the BISHKEK and LIDAR sites, were determined from the data obtained. Calculations on the basis of the RAMS model were performed for these days. These calculations were performed

  11. PRODUCERS’ PERCEPTION OF GEOGRAPHICAL INDICATIONS AS A PRODUCT DIVERSIFICATION TOOL FOR AGRIFOOD PRODUCTS IN SEMI-ARID REGIONS OF KENYA

    Directory of Open Access Journals (Sweden)

    Fredah Wangui Maina

    2018-04-01

    Full Text Available The study assessed producers’ awareness and perceptions of territorial-based qualities and the economic potential of two potential origin-based geographical indications in two semi-arid counties in Kenya. Protection of the origin products as geographical indications is presented as an option for ecosystem approach in managing fragile semi-arid regions while providing producers economic incentives and social inclusion; key components of green growth. Factor analysis was conducted on Likert scale perception questions administered to producers of goats (Baringo and mangoes (Makueni. The producers were aware of the uniqueness of their products and its geographical source. The resultant factors reveal the importance of public policies, institutions, market access and public sector actors as important to producers’ perception of the success of protecting their products as geographical indications. Clustering revealed producer heterogeneity in their perceptions of protecting their respective products as geographical indications. The constitution of the clusters was significantly different based on the number of years the producers had practiced farming in the region, their awareness of the uniqueness of their goats, income received from goat production and institutional factors. Enhanced collective action for both goats and mangoes in the semi-arid regions would ensure collective reputation in the product presented to the market. The producers’ perceptions emphasise geographical indications as a marketing tool rather than an environmental tool, agreeing with Principle 4 of the ecosystem approach on managing ecosystem in an economic context.

  12. Effects of enhanced ultraviolet radiation-B on maize in arid regions of middle-high elevation

    International Nuclear Information System (INIS)

    Zhang Lei; Wang Lianxi; Li Fusheng

    2009-01-01

    [Objective]The experiment aimed to explore the influence of enhanced ultraviolet radiation-B on maize in arid regions of middle-high elevation for correct assessing the influence of enhanced ultraviolet radiation-B on maize and providing scientific reference to make proper countermeasures.[Method] The location test in field and lift lamp of UV-B were used to observe the changes of maize height , leaf area and number of green leaves under influences of different UV-B radiation. [Result]In arid regions of middle-high elevation, enhanced ultraviolet radiation-B could dwarf maize plant, decrease leaf area, decline number of green leaves and yield. The reason of decreasing leaf area was that enhanced ultraviolet radiation-B shortened leaf length and leaf width while the reason of declining yield was that yield components were all negatively influenced and with the increase of ultraviolet radiation-B, the yield declined dramatically.[Conclusion]The result of this experiment would be good for maize production in arid regions of middle-high elevation

  13. Comparing soil organic carbon dynamics in perennial grasses and shrubs in a saline-alkaline arid region, northwestern China.

    Science.gov (United States)

    Zhou, Yong; Pei, Zhiqin; Su, Jiaqi; Zhang, Jingli; Zheng, Yuanrun; Ni, Jian; Xiao, Chunwang; Wang, Renzhong

    2012-01-01

    Although semi-arid and arid regions account for about 40% of terrestrial surface of the Earth and contain approximately 10% of the global soil organic carbon stock, our understanding of soil organic carbon dynamics in these regions is limited. A field experiment was conducted to compare soil organic carbon dynamics between a perennial grass community dominated by Cleistogenes squarrosa and an adjacent shrub community co-dominated by Reaumuria soongorica and Haloxylon ammodendron, two typical plant life forms in arid ecosystems of saline-alkaline arid regions in northwestern China during the growing season 2010. We found that both fine root biomass and necromass in two life forms varied greatly during the growing season. Annual fine root production in the perennial grasses was 45.6% significantly higher than in the shrubs, and fine root turnover rates were 2.52 and 2.17 yr(-1) for the perennial grasses and the shrubs, respectively. Floor mass was significantly higher in the perennial grasses than in the shrubs due to the decomposition rate of leaf litter in the perennial grasses was 61.8% lower than in the shrubs even though no significance was detected in litterfall production. Soil microbial biomass and activity demonstrated a strong seasonal variation with larger values in May and September and minimum values in the dry month of July. Observed higher soil organic carbon stocks in the perennial grasses (1.32 Kg C m(-2)) than in the shrubs (1.12 Kg C m(-2)) might be attributed to both greater inputs of poor quality litter that is relatively resistant to decay and the lower ability of microorganism to decompose these organic matter. Our results suggest that the perennial grasses might accumulate more soil organic carbon with time than the shrubs because of larger amounts of inputs from litter and slower return of carbon through decomposition.

  14. Impacts of urbanization on nitrogen cycling and aerosol, surface and groundwater transport in semi-arid regions

    Science.gov (United States)

    Lohse, K. A.; Gallo, E.; Carlson, M.; Riha, K. M.; Brooks, P. D.; McIntosh, J. C.; Sorooshian, A.; Michalski, G. M.; Meixner, T.

    2011-12-01

    Semi-arid regions are experiencing disproportionate increases in human population and land transformation worldwide, taxing limited water resources and altering nitrogen (N) biogeochemistry. How the redistribution of water and N by urbanization affects semi-arid ecosystems and downstream water quality (e.g. drinking water) is unclear. Understanding these interactions and their feedbacks will be critical for developing science-based management strategies to sustain these limited resources. This is especially true in the US where some of the fastest growing urban areas are in semi-arid ecosystems, where N and water cycles are accelerated, and intimately coupled, and where runoff from urban ecosystems is actively managed to augment a limited water supply to the growing human population. Here we synthesize several ongoing studies from the Tucson Basin in Arizona and examine how increasing urban land cover is altering rainfall-runoff relationships, groundwater recharge, water quality, and long range transport of atmospheric N. Studies across 5 catchments varying in impervious land cover showed that only the least impervious catchment responded to antecedent moisture conditions while hydrologic responses were not statistically related to antecedent rainfall conditions at more impervious sites. Regression models indicated that rainfall depth, imperviousness, and their combined effect control discharge and runoff ratios (p channel characteristics and infrastructure controlled runoff chemistry. Groundwater studies showed nonpoint source contamination of CFCs and associated nitrate in areas of rapid recharge along ephemeral channels. Aerosol measurements indicate that both long-range transport of N and N emissions from Tucson are being transported and deposited at high elevation in areas that recharge regional groundwater. Combined, our findings suggest that urbanization in semi-arid regions results in tradeoffs in the redistribution of water and N that have important

  15. ARBUSCULAR MYCORRHIZAL FUNGI IN SUCCESSIONAL STAGES OF CAATINGA IN THE SEMI-ARID REGION OF BRAZIL

    Directory of Open Access Journals (Sweden)

    Carla da Silva Sousa

    2014-03-01

    Full Text Available http://dx.doi.org/10.5902/1980509813331Caatinga is an exclusively Brazilian biome with areas in accentuated process of desertification. Arbuscularmycorrhizal fungi (AMF act in plant succession by favoring the establishment of plant species typical ofsuccessional stages and by accelerating recovery leading to a climax stage. The objective of the present workwas to evaluate the occurrence and diversity of AMF in successional stages of caatinga in the semi-aridregion of Paraíba State. Experimental plots (30 x 60 m were delimitated in 2007 in areas corresponding todifferent caatinga successional stages: early caatinga succession (natural revegetation during the previous15 years; intermediate (natural revegetation for about 35 years; late (mature caatinga with more than50 years without major disturbances; and also in pasture areas fenced and protected to represent the initialphase of succession. Plots of all four stages were implemented with three replicates. Soil and root sampleswere collected in the experimental plots, from the 0-15 cm soil layer in the dry and in the rainy seasons.All areas presented low infectivity potential suggesting that the introduction of mycorrhizal seedlings mayaccelerate the process of revegetation of degraded soils in this region. Except for the areas of late stage, theglomalin reservoirs increased along with the advancement of the succession process. Areas in the late stageof succession presented greater richness of AMF species, indicating that the establishment of the vegetationalso exerts a significant effect in the fungal community. Glomus and Acaulospora species were predominantin both seasons, possibly because they are well adapted to semi-arid conditions

  16. Estimating Daily Reference Evapotranspiration in a Semi-Arid Region Using Remote Sensing Data

    Directory of Open Access Journals (Sweden)

    Peshawa M. Najmaddin

    2017-07-01

    Full Text Available Estimating daily evapotranspiration is challenging when ground observation data are not available or scarce. Remote sensing can be used to estimate the meteorological data necessary for calculating reference evapotranspiration ETₒ. Here, we assessed the accuracy of daily ETₒ estimates derived from remote sensing (ETₒ-RS compared with those derived from four ground-based stations (ETₒ-G in Kurdistan (Iraq over the period 2010–2014. Near surface air temperature, relative humidity and cloud cover fraction were derived from the Atmospheric Infrared Sounder/Advanced Microwave Sounding Unit (AIRS/AMSU, and wind speed at 10 m height from MERRA (Modern-Era Retrospective Analysis for Research and Application. Four methods were used to estimate ETₒ: Hargreaves–Samani (HS, Jensen–Haise (JH, McGuinness–Bordne (MB and the FAO Penman Monteith equation (PM. ETₒ-G (PM was adopted as the main benchmark. HS underestimated ETₒ by 2%–3% (R2 = 0.86 to 0.90; RMSE = 0.95 to 1.2 mm day−1 at different stations. JH and MB overestimated ETₒ by 8% to 40% (R2= 0.85 to 0.92; RMSE from 1.18 to 2.18 mm day−1. The annual average values of ETₒ estimated using RS data and ground-based data were similar to one another reflecting low bias in daily estimates. They ranged between 1153 and 1893 mm year−1 for ETₒ-G and between 1176 and 1859 mm year−1 for ETₒ-RS for the different stations. Our results suggest that ETₒ-RS (HS can yield accurate and unbiased ETₒ estimates for semi-arid regions which can be usefully employed in water resources management.

  17. Retrieval of Aerosol Optical Depth in the Arid or Semiarid Region of Northern Xinjiang, China

    Directory of Open Access Journals (Sweden)

    Xinpeng Tian

    2018-01-01

    Full Text Available Satellite remote sensing has been widely used to retrieve aerosol optical depth (AOD, which is an indicator of air quality as well as radiative forcing. The dark target (DT algorithm is applied to low reflectance areas, such as dense vegetation, and the deep blue (DB algorithm is adopted for bright-reflecting regions. However, both DT and DB algorithms ignore the effect of surface bidirectional reflectance. This paper provides a method for AOD retrieval in arid or semiarid areas, in which the key points are the accurate estimation of surface reflectance and reasonable assumptions of the aerosol model. To reduce the uncertainty in surface reflectance, a minimum land surface reflectance database at the spatial resolution of 500 m for each month was constructed based on the moderate-resolution imaging spectroradiometer (MODIS surface reflectance product. Furthermore, a bidirectional reflectance distribution function (BRDF correction model was adopted to compensate for the effect of surface reflectance anisotropy. The aerosol parameters, including AOD, single scattering albedo, asymmetric factor, Ångström exponent and complex refractive index, are determined based on the observation of two sunphotometers installed in northern Xinjiang from July to August 2014. The AOD retrieved from the MODIS images was validated with ground-based measurements and the Terra-MODIS aerosol product (MOD04. The 500 m AOD retrieved from the MODIS showed high consistency with ground-based AOD measurements, with an average correlation coefficient of ~0.928, root mean square error (RMSE of ~0.042, mean absolute error (MAE of ~0.032, and the percentage falling within the expected error (EE of the collocations is higher than that for the MOD04 DB product. The results demonstrate that the new AOD algorithm is more suitable to represent aerosol conditions over Xinjiang than the DB standard product.

  18. The semi-Arid integrated model (SIM), a regional integrated model assessing water availability, vulnerability, of ecossytems and society in NE-Brazil

    NARCIS (Netherlands)

    Krol, Martinus S.; Jaeger, A.; Bronstert, A.; Krywkow, Jorg

    2001-01-01

    Northeastern Brazil, an example of vulnerable semi-arid regions on the earth, is characterised by water scarcity and vulnerability of natural resources, pronounced climatic variability and social stress situations. Integrated studies involving hydrology, ecology, meteorology, climatology, pedology,

  19. Groundwater Modeling in Coastal Arid Regions Under the Influence of Marine Saltwater Intrusion

    Science.gov (United States)

    Walther, Marc; Kolditz, Olaf; Grundmann, Jens; Liedl, Rudolf

    2010-05-01

    The optimization of an aquifer's "safe yield", especially within agriculturally used regions, is one of the fundamental tasks for nowaday's groundwater management. Due to the limited water ressources in arid regions, conflict of interests arise that need to be evaluated using scenario analysis and multicriterial optimization approaches. In the context of the government-financed research project "International Water Research Alliance Saxony" (IWAS), the groundwater quality for near-coastal, agriculturally used areas is investigated under the influence of marine saltwater intrusion. Within the near-coastal areas of the study region, i.e. the Batinah plains of Northern Oman, an increasing agricultural development could be observed during the recent decades. Simultaneously, a constant lowering of the groundwater table was registered, which is primarily due to the uncontrolled and unsupervised mining of the aquifers for the local agricultural irrigation. Intensively decreased groundwater levels, however, cause an inversion of the hydraulic gradient which is naturally aligned towards the coast. This, in turn,leads to an intrusion of marine saltwater flowing inland, endangering the productivity of farms near the coast. Utilizing the modeling software package OpenGeoSys, which has been developed and constantly enhanced by the Department of Environmental Informatics at the Helmholtz Centre for Environmental Research Leipzig (UFZ; Kolditz et al., 2008), a three-dimensional, density-dependent model including groundwater flow and mass transport is currently being built up. The model, comprehending three selected coastal wadis of interest, shall be used to investigate different management scenarios. The main focus of the groundwater modelling are the optimization of well positions and pumping schemes as well as the coupling with a surface runoff model, which is also used for the determination of the groundwater recharge due to wadi runoff downstream of retention dams. Based on

  20. Abacus to determine soils salinity in presence of saline groundwater in arid zones case of the region of Ouargla

    Science.gov (United States)

    Fergougui, Myriam Marie El; Benyamina, Hind; Boutoutaou, Djamel

    2018-05-01

    In order to remedy the limit of salt intake to the soil surface, it is necessary to study the causes of the soil salinity and find the origin of these salts. The arid areas in the region of Ouargla lie on excessively mineralized groundwater whose level is near the soil surface (0 - 1.5 m). The topography and absence of a reliable drainage system led to the rise of the groundwater beside the arid climatic conditions contributed to the salinization and hydromorphy of the soils. The progress and stabilization of cultures yields in these areas can only occur if the groundwater is maintained (drained) to a depth of 1.6 m. The results of works done to the determination of soil salinity depend mainly on the groundwater's salinity, its depth and the climate.

  1. Forecasting wheat and barley crop production in arid and semi-arid regions using remotely sensed primary productivity and crop phenology: A case study in Iraq.

    Science.gov (United States)

    Qader, Sarchil Hama; Dash, Jadunandan; Atkinson, Peter M

    2018-02-01

    Crop production and yield estimation using remotely sensed data have been studied widely, but such information is generally scarce in arid and semi-arid regions. In these regions, inter-annual variation in climatic factors (such as rainfall) combined with anthropogenic factors (such as civil war) pose major risks to food security. Thus, an operational crop production estimation and forecasting system is required to help decision-makers to make early estimates of potential food availability. Data from NASA's MODIS with official crop statistics were combined to develop an empirical regression-based model to forecast winter wheat and barley production in Iraq. The study explores remotely sensed indices representing crop productivity over the crop growing season to find the optimal correlation with crop production. The potential of three different remotely sensed indices, and information related to the phenology of crops, for forecasting crop production at the governorate level was tested and their results were validated using the leave-one-year-out approach. Despite testing several methodological approaches, and extensive spatio-temporal analysis, this paper depicts the difficulty in estimating crop yield on an annual base using current satellite low-resolution data. However, more precise estimates of crop production were possible. The result of the current research implies that the date of the maximum vegetation index (VI) offered the most accurate forecast of crop production with an average R 2 =0.70 compared to the date of MODIS EVI (Avg R 2 =0.68) and a NPP (Avg R 2 =0.66). When winter wheat and barley production were forecasted using NDVI, EVI and NPP and compared to official statistics, the relative error ranged from -20 to 20%, -45 to 28% and -48 to 22%, respectively. The research indicated that remotely sensed indices could characterize and forecast crop production more accurately than simple cropping area, which was treated as a null model against which to

  2. New Comparative Experiments of Different Soil Types for Farmland Water Conservation in Arid Regions

    Directory of Open Access Journals (Sweden)

    Yiben Cheng

    2018-03-01

    is: clay (54.3 mm, 43.39% of the total irrigation, loam (39.83 mm, 31.83% of the total irrigation, and sand (33.47 mm, 26.75% of the total irrigation. (3 After the irrigation event, DSR below 150 cm occurs for all three soil combinations. This study reveals the characteristics of irrigation-induced soil moisture recharge and DSR, and it shows that farmland consisting of an upper 50 cm plough soil and a lower 100 cm filled clay soil can save more water resource at the study site, which is useful in agricultural control measure and water resource management in arid regions.

  3. The surface water storage problem in arid regions: a case study of ...

    African Journals Online (AJOL)

    Most dams lose capacity as a result of three principal phenomena: leakage, sedimentation and evaporation. The study of these phenomena is particularly important as they can also endanger the dam's stability. Here, we examine the case of the Gargar dam in western Algeria. This dam is located in an arid zone where ...

  4. The complementary relationship in estimation of regional evapotranspiration: An enhanced Advection-Aridity model

    Science.gov (United States)

    Michael T. Hobbins; Jorge A. Ramirez; Thomas C. Brown

    2001-01-01

    Long-term monthly evapotranspiration estimates from Brutsaert and Stricker’s Advection-Aridity model were compared with independent estimates of evapotranspiration derived from long-term water balances for 139 undisturbed basins across the conterminous United States. On an average annual basis for the period 1962-1988 the original model, which uses a Penman wind...

  5. Detection and differentiation of pollution in urban surface soils using magnetic properties in arid and semi-arid regions of northwestern China

    International Nuclear Information System (INIS)

    Wang, Bo; Xia, Dunsheng; Yu, Ye; Jia, Jia; Xu, Shujing

    2014-01-01

    Increasing urbanization and industrialization over the world has caused many social and environmental problems, one of which drawing particular concern is the soil pollution and its ecological degradation. In this study, the efficiency of magnetic methods for detecting and discriminating contaminates in the arid and semi-arid regions of northwestern China was investigated. Topsoil samples from six typical cities (i.e. Karamay, Urumqi, Lanzhou, Yinchuan, Shizuishan and Wuhai) were collected and a systematic analysis of their magnetic properties was conducted. Results indicate that the topsoil samples from the six cities were all dominated by coarse low-coercivity magnetite. In addition, the average magnetite contents in the soils from Urumqi and Lanzhou were shown to be much higher than those from Karamay, Yinchuan, Shizuishan and Wuhai, and they also have relatively higher χ lf and χ fd % when compared with cities in eastern China. Moreover, specific and distinctive soil pollution signals were identified at each sampling site using the combined various magnetic data, reflecting distinct sources. Industrial and traffic-derived pollution was dominant in Urumqi and Lanzhou, in Yinchuan industrial progress was observed to be important with some places affected by vehicle emission, while Karamay, Shizuishan and Wuhai were relatively clean. The magnetic properties of these latter three cities are significantly affected by both anthropogenic pollution and local parent materials from the nearby Gobi desert. The differences in magnetic properties of topsoil samples affected by mixed industrial and simplex traffic emissions are not obvious, but significant differences exist in samples affected by simplex industrial/vehicle emissions and domestic pollution. The combined magnetic analyses thus provide a sensitive and powerful tool for classifying samples according to likely sources, and may even provide a valuable diagnostic tool for discriminating among different cities

  6. Simulated Optimum Sowing Date for Forage Pearl Millet Cultivars in Multilocation Trials in Brazilian Semi-Arid Region.

    Science.gov (United States)

    Santos, Rafael D; Boote, Kenneth J; Sollenberger, Lynn E; Neves, Andre L A; Pereira, Luiz G R; Scherer, Carolina B; Gonçalves, Lucio C

    2017-01-01

    Forage production is primarily limited by weather conditions under dryland production systems in Brazilian semi-arid regions, therefore sowing at the appropriate time is critical. The objectives of this study were to evaluate the CSM-CERES-Pearl Millet model from the DSSAT software suite for its ability to simulate growth, development, and forage accumulation of pearl millet [ Pennisetum glaucum (L.) R.] at three Brazilian semi-arid locations, and to use the model to study the impact of different sowing dates on pearl millet performance for forage. Four pearl millet cultivars were grown during the 2011 rainy season in field experiments conducted at three Brazilian semi-arid locations, under rainfed conditions. The genetic coefficients of the four pearl millet cultivars were calibrated for the model, and the model performance was evaluated with experimental data. The model was run for 14 sowing dates using long-term historical weather data from three locations, to determine the optimum sowing window. Results showed that performance of the model was satisfactory as indicated by accurate simulation of crop phenology and forage accumulation against measured data. The optimum sowing window varied among locations depending on rainfall patterns, although showing the same trend for cultivars within the site. The best sowing windows were from 15 April to 15 May for the Bom Conselho location; 12 April to 02 May for Nossa Senhora da Gloria; and 17 April to 25 May for Sao Bento do Una. The model can be used as a tool to evaluate the effect of sowing date on forage pearl millet performance in Brazilian semi-arid conditions.

  7. Yield and biological nitrogen fixation of cowpea varieties in the semi-arid region of Brazil

    International Nuclear Information System (INIS)

    Santiago de Freitas, Ana Dolores; Fernandes Silva, Acácia; Valadares de Sá Barretto Sampaio, Everardo

    2012-01-01

    Cowpea is an important crop in small properties of the Brazilian semi-arid region, where it is cultivated without fertilizer application. In spite of the fundamental role played by biological Nitrogen fixation (BNF), little is known of the symbiosis between cowpea varieties and native rhizobia or recommended rhizobia strains. A field experiment was conducted aiming to estimate BNF and productivities of local varieties, in association with two previously described bradyrhizobial inoculant strains and native rhizobia (no inoculation). The plants received 20 kg ha −1 of enriched 15 N fertilizer to allow the use of the isotopic dilution method. After harvest (80 days) straw and grain biomass was determined. The varieties differed in grain and straw productivity and in N and N derived from atmosphere (%Ndfa). Corujinha had the highest grain productivity (1147 kg ha −1 ), followed by Sempre Verde (920 kg ha −1 ), Azul (912 kg ha −1 ) and Cariri (889 kg ha −1 ). Costela de Vaca had the highest straw productivity (2258 kg ha −1 ), highest N content in the straw (28 g ha −1 ) and highest BNF (79 %Ndfa, corresponding to 45 kg ha −1 of N for total aboveground biomass and 39 kg ha −1 for the straw), but the lowest grain productivity (381 kg ha −1 ) and the lowest harvest index (0.14). The inoculations did not significantly alter productivities, N contents or %Ndfa but there was a tendency of lower grain productivities in the non-inoculated plants, which was reflected in lower total and biologically fixed N quantities, indicating that the native strains may be slightly less efficient. -- Highlights: ► We estimate N fixation and productivities of local cowpea varieties in Brazil. ► Plants were inoculated or not with two recommended rhizobia strains. ► All local varieties had high proportions of their N derived from the air (%Ndfa). ► They differed in BNF in grain and straw productivity. ► Inoculation did not alter productivities or %Ndfa but

  8. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India.

    Science.gov (United States)

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah; Kotalo, Rama Gopal; Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy; Rajuru Ramakrishna, Reddy; Surendranair, Suresh Babu

    2016-10-01

    This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500nm are found to be 0.47±0.09, 0.34±0.08, 0.29±0.06 and 0.30±0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α380-1020) value is observed maximum in March (1.25±0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33±0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00-08:00 (IST) and evening 19:00-21:00 (IST) hours and one minima noticed during afternoon (13:00-16:00). The highest monthly mean BC concentration is observed in the month of January (3.4±1.2μgm(-3)) and the lowest in July (1.1±0.2μgm(-3)). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be +36.8±1.7Wm(-2), +26.9±0.2Wm(-2), +18.0±0.6Wm(-2) and +18.5±3.1Wm(-2) during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80Wm(-2)) which contributes more increase in atmospheric heating by ~1K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating. Copyright © 2016 Elsevier B.V. All rights reserved.

  9. Improving Estimation of Evapotranspiration under Water-Limited Conditions Based on SEBS and MODIS Data in Arid Regions

    Directory of Open Access Journals (Sweden)

    Chunlin Huang

    2015-12-01

    Full Text Available This study proposes a method for improving the estimation of surface turbulent fluxes in surface energy balance system (SEBS model under water stress conditions using MODIS data. The normalized difference water index (NDWI as an indicator of water stress is integrated into SEBS. To investigate the feasibility of the new approach, the desert-oasis region in the middle reaches of the Heihe River Basin (HRB is selected as the study area. The proposed model is calibrated with meteorological and flux data over 2008–2011 at the Yingke station and is verified with data from 16 stations of the Heihe Watershed Allied Telemetry Experimental Research (HiWATER project in 2012. The results show that soil moisture significantly affects evapotranspiration (ET under water stress conditions in the study area. Adding the NDWI in SEBS can significantly improve the estimations of surface turbulent fluxes in water-limited regions, especially for spare vegetation cover area. The daily ET maps generated by the new model also show improvements in drylands with low ET values. This study demonstrates that integrating the NDWI into SEBS as an indicator of water stress is an effective way to improve the assessment of the regional ET in semi-arid and arid regions.

  10. A pollution fate and transport model application in a semi-arid region: Is some number better than no number?

    Science.gov (United States)

    Özcan, Zeynep; Başkan, Oğuz; Düzgün, H Şebnem; Kentel, Elçin; Alp, Emre

    2017-10-01

    Fate and transport models are powerful tools that aid authorities in making unbiased decisions for developing sustainable management strategies. Application of pollution fate and transport models in semi-arid regions has been challenging because of unique hydrological characteristics and limited data availability. Significant temporal and spatial variability in rainfall events, complex interactions between soil, vegetation and topography, and limited water quality and hydrological data due to insufficient monitoring network make it a difficult task to develop reliable models in semi-arid regions. The performances of these models govern the final use of the outcomes such as policy implementation, screening, economical analysis, etc. In this study, a deterministic distributed fate and transport model, SWAT, is applied in Lake Mogan Watershed, a semi-arid region dominated by dry agricultural practices, to estimate nutrient loads and to develop the water budget of the watershed. To minimize the discrepancy due to limited availability of historical water quality data extensive efforts were placed in collecting site-specific data for model inputs such as soil properties, agricultural practice information and land use. Moreover, calibration parameter ranges suggested in the literature are utilized during calibration in order to obtain more realistic representation of Lake Mogan Watershed in the model. Model performance is evaluated using comparisons of the measured data with 95%CI for the simulated data and comparison of unit pollution load estimations with those provided in the literature for similar catchments, in addition to commonly used evaluation criteria such as Nash-Sutcliffe simulation efficiency, coefficient of determination and percent bias. These evaluations demonstrated that even though the model prediction power is not high according to the commonly used model performance criteria, the calibrated model may provide useful information in the comparison of the

  11. Temporal and Spatial Distribution of Ecological Security in Arid Region Based on GIS: A Case Study in Xinjiang

    Science.gov (United States)

    Zhang, Q.; Song, W.; Yang, J.

    2017-12-01

    Ecological security is close related to the people's survival and development. In the context of the global warming, with the increasingly frequent human activities, ecological and environmental problems have become increasingly prominent. Ecological security has aroused widespread concern, especially in the arid region. It has an important role in national security as well as political security, military security, economic security, social security. Taken Xinjiang as the research area, which is a typical arid region in China, this study establishes an ecological safety assessment indicator system from perspective of the generic process and the formation mechanism of the ecosystem. The framework is based on natural resources dimensions, natural environment dimensions and human disturbance dimensions. Water is the restrictive factor for the development of arid region, so the water resources carrying capacity is the main natural resource of the study area. The natural environment includes SPI(standardized precipitation index), dryness index, landscape vulnerability, NDVI. Human disturbance includes urbanization rate, population density, afforestation area, per capita GDP, water-saving irrigation area, fertilizer and pesticide application, agriculture Mechanical power, energy consumption. The expert scoring method and the coefficient of variation method are used to determine the weight of each indicator, and finally a comprehensive index is constructed to evaluate the ecological security of Xinjiang, that is, the ecological security index. The results indicate that the ecological security of Xinjiang is 0.43, which is in the critical area. The ecological security of Hami, Turpan and Karamay is the lowest, and the ecological security of the Arabian and Yili is the highest. The ecological security of the south in the Xinjiang is higher than that in the north. In short, ecological environment of Xinjiang is in a sensitive period. Effective ecological protection policy

  12. On the peculiarities of subsurface uranium concentrations in the arid regions

    International Nuclear Information System (INIS)

    Kochenov, A.V.; Chernikov, A.A.

    1976-01-01

    The general features of uranium distribution in the zone of hypergenesis of the area under investigation suggest a lack of accumulations due to climatic or landscape factors alone and formed at the expense of background near-clark contents of uranium in primary rocks. The low uranium concentrations in the debris layer of weathered crusts of acidic effusive rocks and granites as well as in salt marshes are of areal distribution and, in practice, never recorded as anomalies. The processes of salt formation in the area discussed appear, in the absence of organic matter in the sediments, to be insufficient by themselves for the accumulation of uranium from its near-clark contents in the primary rocks. At the same time the arid conditions are undoubtedly favorable for the formation and persistence of accumulative diffusion aureoles emphasizing and revealing on the surface the smallest and poorest primary concentrations of uranium. It is inadmissible to extrapolate the results of a study of one area to the entire variety of geomorphological conditions of the arid zone. The data reported show that care should be taken in interpreting uranium anomalies in arid areas, by all means taking account of the geological structure of the particular anomalous area and the uranium resources of the primary rocks

  13. Performance investigation of low – Concentration photovoltaic systems under hot and arid conditions: Experimental and numerical results

    International Nuclear Information System (INIS)

    Yousef, Mohamed S.; Abdel Rahman, Ali K.; Ookawara, S.

    2016-01-01

    Highlights: • Influence of cooling on the performance of photovoltaic systems. • A comprehensive model (optical, thermal, and electrical) was developed. • Experimental measurements were conducted under hot climate conditions. • For conventional photovoltaic with cooling, about 11% more power was obtained. • For concentrated photovoltaic with cooling, about 15% more power was obtained. - Abstract: In this study, a comparative performance analysis was performed between a conventional photovoltaic system and a low-concentration photovoltaic system. Two typical photovoltaic modules and two compound parabolic concentrating photovoltaic systems were examined. A Cooling system was employed to lower the temperature of the solar cells in each of the two configurations. Experimental and numerical investigations of the performance of the two arrangements with and without cooling were presented. Experiments were conducted outdoors at the Egypt-Japan University of Science and Technology, subjected to the hot climate conditions of New Borg El-Arab City, Alexandria, Egypt (Longitude/Latitude: E 029°42′/N 30°55′). A comprehensive system model was established, which comprises an optical model, coupled with thermal and electrical models. The coupled model was developed analytically and solved numerically, using MATLAB software, to assess the overall performance of the two configurations, considering the concentration ratio of the concentrated photovoltaic system to be 2.4X. The results indicated that cooling the solar panels considerably improved the electrical power yield of the photovoltaic systems. By employing cooling, the temperatures of the conventional photovoltaic system and the concentrated photovoltaic system were effectively lowered by approximately 25% and 30%, respectively, resulting in a significant enhancement in the electrical power output of the photovoltaic system by 11% and that of the concentrated photovoltaic system by 15%. Furthermore, the

  14. The linkage between household water consumption and rainfall in the semi-arid region of East Nusa Tenggara, Indonesia

    Science.gov (United States)

    Messakh, J. J.; Moy, D. L.; Mojo, D.; Maliti, Y.

    2018-01-01

    Several studies have shown that the amount of water consumption by communities will depend on the factors of water consumption patterns that are influenced by social, cultural, economic and local climate conditions. Research on the linkage between rainfall and household water consumption in semi-arid areas of Indonesia has never been done. This study has been conducted on 17 regions in NTT, and case study has taken samples in one town and one village. The research used survey and documentation method. The results show that the average amount of household water consumption in semi-arid region of East Nusa Tenggara is 107 liters / person / day. Statistical test results using Pearson correlation found r = -0.194 and sig = 0.448. This means that there is a negative correlation between rainfall and household water consumption. The greater the rainfall the smaller the consumption of water, or the smaller the rainfall the greater the consumption of water, but the linkage is not significant. Research shows that the amount of household water consumption will be influenced by many interrelated factors and none of the most dominant factors, including the size of the rainfall that occurs in a region.

  15. Characterization of the deforestation effect in a semi-arid region by the use of satellite images

    Science.gov (United States)

    Benhanifia, Khatir; Haddouche, Driss; Smahi, Zakaria; Bensaid, Abdelkrim; Hamimed, Abderrahmane

    2004-02-01

    In Algeria, arid and semi-arid regions occupy over than 95% of whole territory. Forests in the semi arid zone constitutes a front face to the advance of the desert towards northern sides. Like in other regions of the world, deforestation phenomenon have a serious consequences on the fragile ecosystem. Severe continuous drought, fires, pasture, insects as well as the absence of a clear forest politics are so many factors that reduced forest areas in this country. However, the conservation of this patrimony must be a priority of any regional development project. This paper describes an evaluating study of the deforestation impact on forests in the region of Djelfa situated in the Saharian Atlas using multitemporal satellite remote sensing data. In order to establish a forest change map, a methodology based on the comparison between normalized difference vegetation indexes (NDVI) generated from satellite images was adopted. For this purpose, a pair of Landsat and (ETM+) images acquired over the region on April 11th, 1987 and march 24th, 2001 have been used. Until being processed, data used have been geometrically and atmospherically corrected. Then, an (NDVI) have been produced for each date. Resulting from compared (NDVI) image presents the forest change map in the study area. Radiometric values of resulting image have been regrouped into three classes according to change types as follow : Increased radiometry = more active vegetation Decreased radiometry = deterioration in vegetation activity Non changed areas = Non changed Investigations made on the terrain permitted to interpret many causes of detected evolutions. Regressive changes were considerable and demonstrates however, the degradation effect on the vegetation state. Some of regressed radiometry are related to forest fires that affected the region in 1994. Almost of regressive changes are due to a deterioration of vegetation caused by multiple factors. Drought, deceases, pasture and infection are considered

  16. An evapotranspiration product for arid regions based on the three-temperature model and thermal remote sensing

    Science.gov (United States)

    Xiong, Yu Jiu; Zhao, Shao Hua; Tian, Fei; Qiu, Guo Yu

    2015-11-01

    An accurate estimation of evapotranspiration (ET) is crucial to better understand the water budget and improve related studies. Satellite remote sensing provides an unprecedented opportunity to map the spatiotemporal distribution of ET. However, ET values from barren or sparsely vegetated areas in arid regions are often assumed to be zero in typical ET products because of their low values. In addition, separating ET into soil evaporation (Es) and vegetation transpiration (Ec) is difficult. To address these challenges, we developed an ET product (MOD3T) based on a three-temperature model and thermal remote sensing, specifically Moderate Resolution Imaging Spectroradiometer (MODIS) data. MOD3T has a spatial resolution of 1 km and a temporal resolution of 8 days. All input parameters except air temperature were obtained from MODIS datasets. Validation in two adjacent arid river basins in northwestern China showed that the mean absolute errors (mean absolute percent errors) between the MOD3T and flux tower ET were 0.71 mm d-1 (18.5%) and 0.16 mm d-1 (24.9%) for a densely vegetated area and sparsely vegetated sandy desert, respectively. The error between the MOD3T and water balance ET was 24 mm y-1 (8.1%). The Ec/ET or Es/ET of MOD3T was comparable to the observed stable oxygen and hydrogen isotopes. Unlike the MODIS ET (MOD16), MOD3T could not provide continuous ET values (as 70% of the MOD16 area lacked data) but exhibited relatively low uncertainty, particularly in cold seasons. Therefore, MOD3T can provide ET, Es and Ec estimates for arid regions within acceptable ranges.

  17. Water movement through a shallow unsaturated zone in an inland arid region: Field drip irrigation experiment under matrix potential control

    Science.gov (United States)

    Zhou, T.; Han, D.; Song, X.

    2017-12-01

    It is vital to study soil water movement in unsaturated zone for evaluating and improving current irrigation mode for prevention and control of soil secondary salinization, especially in inland arid area, where is characterized by strong evaporation, poor drainage system and shallow water table depth. In this study, we investigated the applicability of drip irrigation under matrix potential control during cotton growth seasons in an inland arid region of northwest China. Combined physical observation with stable isotopes tracing method, we studied soil water flow system and recharge sources of shallow groundwater in heavy (Pilot 1) and light (Pilot 2) saline-alkali cotton fields. Evaporation depths (about 50-60 cm) are about the same for both pilots, but infiltration depths (about 60 cm for Pilot 1 and 150 cm for Pilot 2) are very different due to different soil texture, soil structure and soil salt content. Middle layer (about 100 cm thick) is a critical barrier for water exchange between surface and deep layer. Irrigation water is the major source (about 79.6% for Pilot 1 and 81.6% for Pilot 2), while evapotranspiration is the major sink (about 80.7% for Pilot 1 and 83.1% for Pilot 2) of unsaturated zone. The increase of soil water storage is not enough to make up the water shortage of middle layer and thus drip irrigation water doesn't recharge into groundwater for both pilots. Water table rise (about 60 cm for Pilot 1 and 50 cm for Pilot 2) could be caused by lateral groundwater flow instead of vertical infiltration. This irrigation mode could retard the water table rise in this region. However, improving horizontal drainage system may be indispensable for sustainable agriculture development. The study can provide important basis for soil secondary salinization prevention and agricultural water management in inland arid areas.

  18. Evaluating the impact of water conservation on fate of outdoor water use: a study in an arid region.

    Science.gov (United States)

    Qaiser, Kamal; Ahmad, Sajjad; Johnson, Walter; Batista, Jacimaria

    2011-08-01

    In this research, the impact of several water conservation policies and return flow credits on the fate of water used outdoors in an arid region is evaluated using system dynamics modeling approach. Return flow credits is a strategy where flow credits are obtained for treated wastewater returned to a water body, allowing for the withdrawal of additional water equal to the amount returned as treated wastewater. In the return credit strategy, treated wastewater becomes a resource. This strategy creates a conundrum in which conservation may lead to an apparent decrease in water supply because less wastewater is generated and returned to water body. The water system of the arid Las Vegas Valley in Nevada, USA is used as basis for the dynamic model. The model explores various conservation scenarios to attain the daily per capita demand target of 752 l by 2035: (i) status quo situation where conservation is not implemented, (ii) conserving water only on the outdoor side, (iii) conserving water 67% outdoor and 33% indoor, (iv) conserving equal water both in the indoor and outdoor use (v) conserving water only on the indoor side. The model is validated on data from 1993 to 2008 and future simulations are carried out up to 2035. The results show that a substantial portion of the water used outdoor either evapo-transpires (ET) or infiltrates to shallow groundwater (SGW). Sensitivity analysis indicated that seepage to groundwater is more susceptible to ET compared to any other variable. The all outdoor conservation scenario resulted in the highest return flow credits and the least ET and SGW. A major contribution of this paper is in addressing the water management issues that arise when wastewater is considered as a resource and developing appropriate conservation policies in this backdrop. The results obtained can be a guide in developing outdoor water conservation policies in arid regions. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. A Framework Predicting Water Availability in a Rapidly Growing, Semi-Arid Region under Future Climate Change

    Science.gov (United States)

    Han, B.; Benner, S. G.; Glenn, N. F.; Lindquist, E.; Dahal, K. R.; Bolte, J.; Vache, K. B.; Flores, A. N.

    2014-12-01

    Climate change can lead to dramatic variations in hydrologic regime, affecting both surface water and groundwater supply. This effect is most significant in populated semi-arid regions where water availability are highly sensitive to climate-induced outcomes. However, predicting water availability at regional scales, while resolving some of the key internal variability and structure in semi-arid regions is difficult due to the highly non-linearity relationship between rainfall and runoff. In this study, we describe the development of a modeling framework to evaluate future water availability that captures elements of the coupled response of the biophysical system to climate change and human systems. The framework is built under the Envision multi-agent simulation tool, characterizing the spatial patterns of water demand in the semi-arid Treasure Valley area of Southwest Idaho - a rapidly developing socio-ecological system where urban growth is displacing agricultural production. The semi-conceptual HBV model, a population growth and allocation model (Target), a vegetation state and transition model (SSTM), and a statistically based fire disturbance model (SpatialAllocator) are integrated to simulate hydrology, population and land use. Six alternative scenarios are composed by combining two climate change scenarios (RCP4.5 and RCP8.5) with three population growth and allocation scenarios (Status Quo, Managed Growth, and Unconstrained Growth). Five-year calibration and validation performances are assessed with Nash-Sutcliffe efficiency. Irrigation activities are simulated using local water rights. Results show that in all scenarios, annual mean stream flow decreases as the projected rainfall increases because the projected warmer climate also enhances water losses to evapotranspiration. Seasonal maximum stream flow tends to occur earlier than in current conditions due to the earlier peak of snow melting. The aridity index and water deficit generally increase in the

  20. Cyanobacterial blooms in stratified and destratified eutrophic reservoirs in semi-arid region of Brazil

    Directory of Open Access Journals (Sweden)

    Ênio W. Dantas

    2011-12-01

    Full Text Available This study investigated the dynamics of cyanobacteria in two deep, eutrophic reservoirs in a semi-arid region of Brazil during periods of stratification and destratification. Four collections were carried out at each reservoir at two depths at three-month intervals. The following abiotic variables were analyzed: water temperature, dissolved oxygen, pH, turbidity, water transparency, total phosphorus, total dissolved phosphorus, orthophosphate and total nitrogen. Phytoplankton density was quantified for the determination of the biomass of cyanobacteria. The data were analyzed using CCA. Higher mean phytoplankton biomass values (29.8 mm³.L-1 occurred in the period of thermal stratification. A greater similarity in the phytoplankton communities also occurred in this period and was related to the development of cyanobacteria, mainly Cylindrospermopsis raciborskii (>3.9 mm³.L-1. During the period of thermal destratification, this species co-dominated the environment with Planktothrix agardhii, Geitlerinema amphibium, Microcystis aeruginosa and Merismopedia tenuissima, as well as with diatoms and phytoflagellates. Environmental instability and competition among algae hindered the establishment of blooms more during the mixture period than during the stratification period. Thermal changes in the water column caused by climatologic events altered other physiochemical conditions of the water, leading to changes in the composition and biomass of the cyanobacterial community in tropical reservoirs.Este estudo investigou a dinâmica das cianobactérias em dois reservatórios eutróficos e profundos localizados na região semi-árida do Brasil durante períodos de estratificação e desestratificação térmica. Quatro coletas foram feitas em cada reservatório em duas profundidades em intervalo de três meses. As variáveis abióticas analisadas foram: temperatura da água, oxigênio dissolvido, pH, turbidez, transparência da água, fósforo total, f

  1. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India

    Energy Technology Data Exchange (ETDEWEB)

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah [Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh (India); Kotalo, Rama Gopal, E-mail: krgverma@yahoo.com [Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh (India); Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy [Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh (India); Rajuru Ramakrishna, Reddy [Aerosol & Atmospheric Research Laboratory, Department of Physics, Sri Krishnadevaraya University, Anantapur 515 003, Andhra Pradesh (India); Srinivasa Ramanujan Institute of Technology, B.K. Samudram Mandal, Anantapur 515 701, Andhra Pradesh (India); Surendranair, Suresh Babu [Space Physics Laboratory, Vikram Sarabhai Space Centre, Trivandrum 695 022, Kerala (India)

    2016-10-01

    This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500 nm are found to be 0.47 ± 0.09, 0.34 ± 0.08, 0.29 ± 0.06 and 0.30 ± 0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α{sub 380–1020}) value is observed maximum in March (1.25 ± 0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33 ± 0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00–08:00 (IST) and evening 19:00–21:00 (IST) hours and one minima noticed during afternoon (13:00–16:00). The highest monthly mean BC concentration is observed in the month of January (3.4 ± 1.2 μg m{sup −3}) and the lowest in July (1.1 ± 0.2 μg m{sup −3}). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be + 36.8 ± 1.7 W m{sup −2}, + 26.9 ± 0.2 W m{sup −2}, + 18.0 ± 0.6 W m{sup −2} and + 18.5 ± 3.1 W m{sup −2} during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80 W m{sup −2}) which contributes more increase in atmospheric heating by ~ 1 K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating. - Highlights: • The mean values of AOD{sub 500} are found to be high during summer whereas low in monsoon. • The highest values of BC are observed in January and the lowest in the month of July. • The annual mean

  2. Direct radiative forcing properties of atmospheric aerosols over semi-arid region, Anantapur in India

    International Nuclear Information System (INIS)

    Kalluri, Raja Obul Reddy; Gugamsetty, Balakrishnaiah; Kotalo, Rama Gopal; Nagireddy, Siva Kumar Reddy; Tandule, Chakradhar Rao; Thotli, Lokeswara Reddy; Rajuru Ramakrishna, Reddy; Surendranair, Suresh Babu

    2016-01-01

    This paper describes the aerosols optical, physical characteristics and the aerosol radiative forcing pertaining to semi-arid region, Anantapur for the period January 2013-December 2014. Collocated measurements of Aerosol Optical Depth (AOD) and Black Carbon mass concentration (BC) are carried out by using MICROTOPS II and Aethalometer and estimated the aerosol radiative forcing over this location. The mean values of AOD at 500 nm are found to be 0.47 ± 0.09, 0.34 ± 0.08, 0.29 ± 0.06 and 0.30 ± 0.07 during summer, winter, monsoon and post-monsoon respectively. The Angstrom exponent (α_3_8_0_–_1_0_2_0) value is observed maximum in March (1.25 ± 0.19) and which indicates the predominance of fine - mode aerosols and lowest in the month of July (0.33 ± 0.14) and may be due to the dominance of coarse-mode aerosols. The diurnal variation of BC is exhibited two height peaks during morning 07:00–08:00 (IST) and evening 19:00–21:00 (IST) hours and one minima noticed during afternoon (13:00–16:00). The highest monthly mean BC concentration is observed in the month of January (3.4 ± 1.2 μg m"−"3) and the lowest in July (1.1 ± 0.2 μg m"−"3). The estimated Aerosol Direct Radiative Forcing (ADRF) in the atmosphere is found to be + 36.8 ± 1.7 W m"−"2, + 26.9 ± 0.2 W m"−"2, + 18.0 ± 0.6 W m"−"2 and + 18.5 ± 3.1 W m"−"2 during summer, winter, monsoon and post-monsoon seasons, respectively. Large difference between TOA and BOA forcing is observed during summer which indicate the large absorption of radiant energy (36.80 W m"−"2) which contributes more increase in atmospheric heating by ~ 1 K/day. The BC contribution on an average is found to be 64% and is responsible for aerosol atmospheric heating. - Highlights: • The mean values of AOD_5_0_0 are found to be high during summer whereas low in monsoon. • The highest values of BC are observed in January and the lowest in the month of July. • The annual mean atmospheric forcing is found to be

  3. Modelling thermal comfort of visitors at urban squares in hot and arid climate using NN-ARX soft computing method

    Science.gov (United States)

    Kariminia, Shahab; Motamedi, Shervin; Shamshirband, Shahaboddin; Piri, Jamshid; Mohammadi, Kasra; Hashim, Roslan; Roy, Chandrabhushan; Petković, Dalibor; Bonakdari, Hossein

    2016-05-01

    Visitors utilize the urban space based on their thermal perception and thermal environment. The thermal adaptation engages the user's behavioural, physiological and psychological aspects. These aspects play critical roles in user's ability to assess the thermal environments. Previous studies have rarely addressed the effects of identified factors such as gender, age and locality on outdoor thermal comfort, particularly in hot, dry climate. This study investigated the thermal comfort of visitors at two city squares in Iran based on their demographics as well as the role of thermal environment. Assessing the thermal comfort required taking physical measurement and questionnaire survey. In this study, a non-linear model known as the neural network autoregressive with exogenous input (NN-ARX) was employed. Five indices of physiological equivalent temperature (PET), predicted mean vote (PMV), standard effective temperature (SET), thermal sensation votes (TSVs) and mean radiant temperature ( T mrt) were trained and tested using the NN-ARX. Then, the results were compared to the artificial neural network (ANN) and the adaptive neuro-fuzzy inference system (ANFIS). The findings showed the superiority of the NN-ARX over the ANN and the ANFIS. For the NN-ARX model, the statistical indicators of the root mean square error (RMSE) and the mean absolute error (MAE) were 0.53 and 0.36 for the PET, 1.28 and 0.71 for the PMV, 2.59 and 1.99 for the SET, 0.29 and 0.08 for the TSV and finally 0.19 and 0.04 for the T mrt.

  4. Recent changes in continentality and aridity conditions over the Middle East and North Africa region, and their association with circulation patterns

    KAUST Repository

    El Kenawy, Ahmed M.

    2016-05-30

    A long-term (1960-2013) assessment of the variability of continentality and aridity conditions over the Middle East and North Africa (MENA) region was undertaken. Monthly gridded temperature and precipitation data from the Climate Research Unit (CRU) (TS3.22 version) were used to compute the Johansson Continentality Index (JCI) and the Marsz Oceanity Index (MOI). In addition, the De Martonne index and the Pinna index were employed to assess recent changes in aridity conditions. All indices revealed a statistically significant increase in continental influences over the region, particularly in the Nile Basin and the Fertile Crescent. For aridity, the results suggested a generally statistically insignificant increase, with the most rapid changes occurring over the most humid regions (i.e. the Ethiopian Highlands and the Fertile Crescent). In order to explain the observed changes in the continentality and aridity conditions, we assessed the relationship between aridity and continentality indices and a wide range of large-scale circulation patterns. Results indicate that the spatial variability of continentality (as well as aridity) was closely coupled with the Atlantic modes of variability, e.g. the Eastern Atlantic pattern and the Atlantic Meridional Mode, compared to those of the Mediterranean Sea and the Indian Ocean. The results of this work highlight change processes in 2 important climate features in one of the hottest regions on Earth. Improving our understanding of the spatio-temporal characteristics of climate continentality and aridity has implications for a diversity of socio-political, economic, hydrological, and ecological activities in the MENA region.

  5. Recent changes in continentality and aridity conditions over the Middle East and North Africa region, and their association with circulation patterns

    KAUST Repository

    El Kenawy, Ahmed M.; McCabe, Matthew; Vicente-Serrano, Sergio M.; Robaa, Sayed M.; Lopez-Moreno, Juan I.

    2016-01-01

    A long-term (1960-2013) assessment of the variability of continentality and aridity conditions over the Middle East and North Africa (MENA) region was undertaken. Monthly gridded temperature and precipitation data from the Climate Research Unit (CRU) (TS3.22 version) were used to compute the Johansson Continentality Index (JCI) and the Marsz Oceanity Index (MOI). In addition, the De Martonne index and the Pinna index were employed to assess recent changes in aridity conditions. All indices revealed a statistically significant increase in continental influences over the region, particularly in the Nile Basin and the Fertile Crescent. For aridity, the results suggested a generally statistically insignificant increase, with the most rapid changes occurring over the most humid regions (i.e. the Ethiopian Highlands and the Fertile Crescent). In order to explain the observed changes in the continentality and aridity conditions, we assessed the relationship between aridity and continentality indices and a wide range of large-scale circulation patterns. Results indicate that the spatial variability of continentality (as well as aridity) was closely coupled with the Atlantic modes of variability, e.g. the Eastern Atlantic pattern and the Atlantic Meridional Mode, compared to those of the Mediterranean Sea and the Indian Ocean. The results of this work highlight change processes in 2 important climate features in one of the hottest regions on Earth. Improving our understanding of the spatio-temporal characteristics of climate continentality and aridity has implications for a diversity of socio-political, economic, hydrological, and ecological activities in the MENA region.

  6. Efficiency of water and fertilizer use in semi-arid regions

    International Nuclear Information System (INIS)

    1976-01-01

    The proceedings contain 14 papers considering problems on soil and soil water, irrigation, and the use of fertilizers in semi-arid zones. Research projects in these fields are discussed and results obtained so far are reported (tables and diagrams on the behaviour of water and fertilizers in soils). The use of radioisotope techniques is mentioned briefly. Finally, some future ''first priority'' research areas are identified and recommendations for further research programs are given. These programs aim at reducing the hazards of crop failure and at increasing production under dry farming conditions

  7. An examination of recharge mound decay and fossil gradients in arid regional sedimentary basins

    International Nuclear Information System (INIS)

    Lloyd, J.W.

    1980-01-01

    In many of the vast arid sedimentary basins of the world, groundwater gradients exist that appear to be anomalous in the context of the probable modern recharge potential. The possibility that such gradients are in fact remnant fossil conditions representing the decay of ancient recharge mounds is examined. An example of decay condition is represented using a resistor-network analogue model in which the time control is based on 14 C ages. The decay hypothesis is found to be plausible with realistic aquifer characteristics but a non-homogeneous flow is indicated from the 14 C data. (author)

  8. Agronomic performance of onion hybrids in Baraúna, in the semi-arid region of Brazil

    Directory of Open Access Journals (Sweden)

    Renato Leandro Costa Nunes

    Full Text Available In the Brazilian state of Rio Grande do Norte, the significant planting of onions is relatively recent, with producers seeking alternative ways to reduce losses. As a result, it was aimed to evaluate the agronomic performance of onion hybrids in the town of Baraúna in the semi-arid region of Rio Grande do Norte. The experimental design was of randomised blocks with six replications. Treatments consisted of eight hybrids (Cronus F1, Predilata F1, Serena F1, Fortaleza F1, Mata Hari, Luana, Lambada, Don Victor and a control cultivar (IPA 11. The following were evaluated: average plant height; average number of leaves; diameter of the pseudostem; productivity; average bulb weight; rate of survival; leaf-waxiness; cultivar cycle; commercial classification of the bulbs. The Serena F1 and Mata Hari cultivars are recommended for the northeast semi-arid region due to high productivity, early cycle and better bulb classification. The use of these cultivars may help, in the short term, to change cultivation of the onion in the state of Rio Grande do Norte.

  9. Remote sensing based crop type mapping and evapotranspiration estimates at the farm level in arid regions of the globe

    Science.gov (United States)

    Ozdogan, M.; Serrat-Capdevila, A.; Anderson, M. C.

    2017-12-01

    Despite increasing scarcity of freshwater resources, there is dearth of spatially explicit information on irrigation water consumption through evapotranspiration, particularly in semi-arid and arid geographies. Remote sensing, either alone or in combination with ground surveys, is increasingly being used for irrigation water management by quantifying evaporative losses at the farm level. Increased availability of observations, sophisticated algorithms, and access to cloud-based computing is also helping this effort. This presentation will focus on crop-specific evapotranspiration estimates at the farm level derived from remote sensing in a number of water-scarce regions of the world. The work is part of a larger effort to quantify irrigation water use and improve use efficiencies associated with several World Bank projects. Examples will be drawn from India, where groundwater based irrigation withdrawals are monitored with the help of crop type mapping and evapotranspiration estimates from remote sensing. Another example will be provided from a northern irrigation district in Mexico, where remote sensing is used for detailed water accounting at the farm level. These locations exemplify the success stories in irrigation water management with the help of remote sensing with the hope that spatially disaggregated information on evapotranspiration can be used as inputs for various water management decisions as well as for better water allocation strategies in many other water scarce regions.

  10. Does GPM-based multi-satellite precipitation enhance rainfall estimates over Pakistan and Bolivia arid regions?

    Science.gov (United States)

    Hussain, Y.; Satgé, F.; Bonnet, M. P.; Pillco, R.; Molina, J.; Timouk, F.; Roig, H.; Martinez-Carvajal, H., Sr.; Gulraiz, A.

    2016-12-01

    Arid regions are sensitive to rainfall variations which are expressed in the form of flooding and droughts. Unfortunately, those regions are poorly monitored and high quality rainfall estimates are still needed. The Global Precipitation Measurement (GPM) mission released two new satellite rainfall products named Integrated Multisatellite Retrievals GPM (IMERG) and Global Satellite Mapping of Precipitation version 6 (GSMaP-v6) bringing the possibility of accurate rainfall monitoring over these countries. This study assessed both products at monthly scale over Pakistan considering dry and wet season over the 4 main climatic zones from 2014 to 2016. With similar climatic conditions, the Altiplano region of Bolivia is considered to quantify the influence of big lakes (Titicaca and Poopó) in rainfall estimates. For comparison, the widely used TRMM-Multisatellite Precipitation Analysis 3B43 (TMPA-3B43) version 7 is also involved in the analysis to observe the potential enhancement in rainfall estimate brought by GPM products. Rainfall estimates derived from 110 rain-gauges are used as reference to compare IMERG, GSMaP-v6 and TMPA-3B43 at the 0.1° and 0.25° spatial resolution. Over both regions, IMERG and GSMaP-v6 capture the spatial pattern of precipitation as well as TMPA-3B43. All products tend to over estimates rainfall over very arid regions. This feature is even more marked during dry season. However, during this season, both reference and estimated rainfall remain very low and do not impact seasonal water budget computation. On a general way, IMERG slightly outperforms TMPA-3B43 and GSMaP-v6 which provides the less accurate rainfall estimate. The TMPA-3B43 rainfall underestimation previously found over Lake Titicaca is still observed in IMERG estimates. However, GSMaP-v6 considerably decreases the underestimation providing the most accurate rainfall estimate over the lake. MOD11C3 Land Surface Temperature (LST) and ASTER Global Emissivity Dataset reveal strong

  11. Amphibian and reptile biodiversity in the semi-arid region of the municipality of Nopala de Villagrán, Hidalgo, Mexico.

    Science.gov (United States)

    Roth-Monzón, Andrea J; Mendoza-Hernández, Andrés Alberto; Flores-Villela, Oscar

    2018-01-01

    Current global changes are putting both biodiversity and the processes that depend on it at risk. This is especially true for semi-arid regions and the flagship groups that inhabit them, such as amphibians and reptiles. Semi-arid regions are often thought to have lower biodiversity and thus have been overlooked, resulting in the underestimation of their biological richness. Therefore, the aim of this study was to conduct an inventory of amphibians and reptiles in the semi-arid municipality of Nopala de Villagrán, Mexico, and analyze its biodiversity in relation to the seasons, vegetation and microhabitat. During a year of fieldwork, we found 24 species in the area, most of them of low abundance, and one of which was recorded for the first time for the state of Hidalgo. We documented five amphibian species and 19 reptile species. We also found that observed species richness was higher in the rainy season and in xeric scrub vegetation, although only the season differences were significant according to rarefaction curves. Our findings highlight the importance of seasonality and vegetation type for the species that inhabit this semi-arid region. This study broadens our understanding of the importance of semi-arid regions and, by extension, that of other areas with similar characteristics.

  12. Amphibian and reptile biodiversity in the semi-arid region of the municipality of Nopala de Villagrán, Hidalgo, Mexico

    Directory of Open Access Journals (Sweden)

    Andrea J. Roth-Monzón

    2018-01-01

    Full Text Available Current global changes are putting both biodiversity and the processes that depend on it at risk. This is especially true for semi-arid regions and the flagship groups that inhabit them, such as amphibians and reptiles. Semi-arid regions are often thought to have lower biodiversity and thus have been overlooked, resulting in the underestimation of their biological richness. Therefore, the aim of this study was to conduct an inventory of amphibians and reptiles in the semi-arid municipality of Nopala de Villagrán, Mexico, and analyze its biodiversity in relation to the seasons, vegetation and microhabitat. During a year of fieldwork, we found 24 species in the area, most of them of low abundance, and one of which was recorded for the first time for the state of Hidalgo. We documented five amphibian species and 19 reptile species. We also found that observed species richness was higher in the rainy season and in xeric scrub vegetation, although only the season differences were significant according to rarefaction curves. Our findings highlight the importance of seasonality and vegetation type for the species that inhabit this semi-arid region. This study broadens our understanding of the importance of semi-arid regions and, by extension, that of other areas with similar characteristics.

  13. Amphibian and reptile biodiversity in the semi-arid region of the municipality of Nopala de Villagrán, Hidalgo, Mexico

    Science.gov (United States)

    Mendoza-Hernández, Andrés Alberto; Flores-Villela, Oscar

    2018-01-01

    Current global changes are putting both biodiversity and the processes that depend on it at risk. This is especially true for semi-arid regions and the flagship groups that inhabit them, such as amphibians and reptiles. Semi-arid regions are often thought to have lower biodiversity and thus have been overlooked, resulting in the underestimation of their biological richness. Therefore, the aim of this study was to conduct an inventory of amphibians and reptiles in the semi-arid municipality of Nopala de Villagrán, Mexico, and analyze its biodiversity in relation to the seasons, vegetation and microhabitat. During a year of fieldwork, we found 24 species in the area, most of them of low abundance, and one of which was recorded for the first time for the state of Hidalgo. We documented five amphibian species and 19 reptile species. We also found that observed species richness was higher in the rainy season and in xeric scrub vegetation, although only the season differences were significant according to rarefaction curves. Our findings highlight the importance of seasonality and vegetation type for the species that inhabit this semi-arid region. This study broadens our understanding of the importance of semi-arid regions and, by extension, that of other areas with similar characteristics. PMID:29312825

  14. Renewable energies and regional development. Photovoltaic energy, micro-grid systems in the Brazilian semi-arid

    Energy Technology Data Exchange (ETDEWEB)

    Arrais de Miranda Mousinho, Maria Candida

    2012-07-01

    This article tackles the issue of the development related to the insertion of new renewable energy technologies. It also presents the experience of the region of the Sao Francisco River Valley - named after the largest river genuinely Brazilian located in the semi-arid region -, focusing mainly on two municipalities: Xique-Xique and Barra. Its focus is the use of solar energy for rural communities. To present the results of that experience, the support of the Rio Sao Francisco Project: culture, identity and development, of the Deutsche Gesellschaft fuer Internationale Zusammenarbeit (GIZ) and of Eurosolar was essential. The research on which this article is based was fruit of a volunteer research project linked to the Partners of the Americas Bahia-Pennsylvania Committee.

  15. Investigating transport capacity equations in sediment yield modelling for the Cariri semi-arid region of Paraiba-PB/Brazil

    Directory of Open Access Journals (Sweden)

    E. E. De Figueiredo

    2015-03-01

    Full Text Available In the semi arid Cariri region of the state of Paraiba, Brazil, runoff is of the Hortonian type generated by excess of rainfall over infiltration capacity, and soil erosion is governed by rainfall intensity and sediment size. However, the governing sediment transport mechanism is not well understood. Sediment transport generally depends on the load of sediment provided by soil erosion and on the transport capacity of the flow. The latter is mainly governed by mechanisms such as water shear stress, or stream power. Accordingly, the load of sediment transported by the flow may vary depending on the mechanism involved in the equation of estimation. Investigation of the sediment transport capacity of the flow via a distributed physically-based model is an important and necessary task, but quite rare in semi-arid climates, and particularly in the Cariri region of the state of Paraíba/Brazil. In this study, the equations of Yalin, Engelund & Hansen, Laursen, DuBoys and Bagnold have been coupled with the MOSEE distributed physically based model aiming at identifying the mechanisms leading to the best model simulations when compared with data observed at various basin scales and land uses in the study region. The results obtained with the investigated methods were quite similar and satisfactory suggesting the feasibility of the mechanisms involved, but the observed values were better represented with Bagnold’s equation, which is physically grounded on the stream power, and we recommend it for simulations of similar climate, runoff generation mechanisms and sediment characteristics as in the study region.

  16. Mapping Annual Forest Cover in Sub-Humid and Semi-Arid Regions through Analysis of Landsat and PALSAR Imagery

    Directory of Open Access Journals (Sweden)

    Yuanwei Qin

    2016-11-01

    Full Text Available Accurately mapping the spatial distribution of forests in sub-humid to semi-arid regions over time is important for forest management but a challenging task. Relatively large uncertainties still exist in the spatial distribution of forests and forest changes in the sub-humid and semi-arid regions. Numerous publications have used either optical or synthetic aperture radar (SAR remote sensing imagery, but the resultant forest cover maps often have large errors. In this study, we propose a pixel- and rule-based algorithm to identify and map annual forests from 2007 to 2010 in Oklahoma, USA, a transitional region with various climates and landscapes, using the integration of the L-band Advanced Land Observation Satellite (ALOS PALSAR Fine Beam Dual Polarization (FBD mosaic dataset and Landsat images. The overall accuracy and Kappa coefficient of the PALSAR/Landsat forest map were about 88.2% and 0.75 in 2010, with the user and producer accuracy about 93.4% and 75.7%, based on the 3270 random ground plots collected in 2012 and 2013. Compared with the forest products from Japan Aerospace Exploration Agency (JAXA, National Land Cover Database (NLCD, Oklahoma Ecological Systems Map (OKESM and Oklahoma Forest Resource Assessment (OKFRA, the PALSAR/Landsat forest map showed great improvement. The area of the PALSAR/Landsat forest was about 40,149 km2 in 2010, which was close to the area from OKFRA (40,468 km2, but much larger than those from JAXA (32,403 km2 and NLCD (37,628 km2. We analyzed annual forest cover dynamics, and the results show extensive forest cover loss (2761 km2, 6.9% of the total forest area in 2010 and gain (3630 km2, 9.0% in southeast and central Oklahoma, and the total area of forests increased by 684 km2 from 2007 to 2010. This study clearly demonstrates the potential of data fusion between PALSAR and Landsat images for mapping annual forest cover dynamics in sub-humid to semi-arid regions, and the resultant forest maps would be

  17. Hierarchical distance-based fuzzy approach to evaluate urban water supply systems in a semi-arid region.

    Science.gov (United States)

    Yekta, Tahereh Sadeghi; Khazaei, Mohammad; Nabizadeh, Ramin; Mahvi, Amir Hossein; Nasseri, Simin; Yari, Ahmad Reza

    2015-01-01

    Hierarchical distance-based fuzzy multi-criteria group decision making was served as a tool to evaluate the drinking water supply systems of Qom, a semi-arid city located in central part of Iran. A list of aspects consisting of 6 criteria and 35 sub-criteria were evaluated based on a linguistic term set by five decision-makers. Four water supply alternatives including "Public desalinated distribution system", "PET Bottled Drinking Water", "Private desalinated water suppliers" and "Household desalinated water units" were assessed based on criteria and sub-criteria. Data were aggregated and normalized to apply Performance Ratings of Alternatives. Also, the Performance Ratings of Alternatives were aggregated again to achieve the Aggregate Performance Ratings. The weighted distances from ideal solution and anti-ideal solution were calculated after secondary normalization. The proximity of each alternative to the ideal solution was determined as the final step. The alternatives were ranked based on the magnitude of ideal solutions. Results showed that "Public desalinated distribution system" was the most appropriate alternative to supply the drinking needs of Qom population. Also, "PET Bottled Drinking Water" was the second acceptable option. A novel classification of alternatives to satisfy the drinking water requirements was proposed which is applicable for the other cities located in semi-arid regions of Iran. The health issues were considered as independent criterion, distinct from the environmental issues. The constraints of high-tech alternatives were also considered regarding to the level of dependency on overseas.

  18. Assessing anthropogenic impacts on limited water resources under semi-arid conditions: three-dimensional transient regional modelling in Jordan

    Science.gov (United States)

    Rödiger, Tino; Magri, Fabien; Geyer, Stefan; Morandage, Shehan Tharaka; Ali Subah, H. E.; Alraggad, Marwan; Siebert, Christian

    2017-11-01

    Both increasing aridity and population growth strongly stress freshwater resources in semi-arid areas such as Jordan. The country's second largest governorate, Irbid, with over 1 million inhabitants, is already suffering from an annual water deficit of 25 million cubic meters (MCM). The population is expected to double within the next 20 years. Even without the large number of refugees from Syria, the deficit will likely increase to more then 50 MCM per year by 2035 The Governorate's exclusive resource is groundwater, abstracted by the extensive Al Arab and Kufr Asad well fields. This study presents the first three-dimensional transient regional groundwater flow model of the entire Wadi al Arab to answer important questions regarding the dynamic quality and availability of water within the catchment. Emphasis is given to the calculation and validation of the dynamic groundwater recharge, derived from a multi-proxy approach, including (1) a hydrological model covering a 30-years dataset, (2) groundwater level measurements and (3) information about springs. The model enables evaluation of the impact of abstraction on the flow regime and the groundwater budget of the resource. Sensitivity analyses of controlling parameters indicate that intense abstraction in the southern part of the Wadi al Arab system can result in critical water-level drops of 10 m at a distance of 16 km from the production wells. Moreover, modelling results suggest that observed head fluctuations are strongly controlled by anthropogenic abstraction rather than variable recharge rates due to climate changes.

  19. Development of an Evapotranspiration Data Assimilation Technique for Streamflow Estimates: A Case Study in a Semi-Arid Region

    Directory of Open Access Journals (Sweden)

    Ying Zhang

    2017-09-01

    Full Text Available Streamflow estimates are substantially important as fresh water shortages increase in arid and semi-arid regions where evapotranspiration (ET is a significant contribution to the water balance. In this regard, evapotranspiration data can be assimilated into a distributed hydrological model (SWAT, Soil and Water Assessment Tool for improving streamflow estimates. The SWAT model has been widely used for streamflow estimations, but the applications combining SWAT and ET products were rare. Thus, this study aims to develop a SWAT-based evapotranspiration data assimilation system. In particular, SWAT is gridded at Hydrologic Response Unit (HRU level to incorporate gridded ET products acquired from the remote sensing-based ETMonitor model. In the modeling case, Gridded SWAT (GSWAT shows a good agreement of streamflow modeling with the original SWAT. Such a scant margin between them is due to the modeling domain mismatch caused by different HRU delineations. In the ET assimilation case, we carry out a synthetic data experiment to illustrate the state augmentation Direct Insertion (DI method and a real data experiment for the upper Heihe River Basin. The results demonstrate the benefits of the ET assimilation for improving hydrologic processes representations. In the future, more remotely sensed data can be assimilated into the data assimilation system to provide more reliable hydrological predictions.

  20. Simple equation for estimating actual evapotranspiration using heat units for wheat in arid regions

    Directory of Open Access Journals (Sweden)

    M.A. Salama

    2015-07-01

    Application of treatment (B resulted in highly significant increase in yield production of Gemmeza10 and Misr2 as compared to treatment (A. Grain yield of different wheat varieties grown under treatment (B could be ranked in the following descending order: Misr2 > Gemmeza10 > Sids12. While under treatment (A it could be arranged in the following descending order: Misr2 > Sids12 > Gemmeza10. On the other hand, the overall means indicated non-significant difference between all wheat verities. The highest values of water and irrigation use efficiency as well as heat use efficiency were obtained with treatment (B. The equation used in the present study is available to estimate ETa under arid climate with drip irrigation system.

  1. Optimum contracted-for water supply for hotels in arid coastal regions.

    Science.gov (United States)

    Lamei, A; von Münch, E; van der Zaag, P; Imam, E

    2009-01-01

    Hotels in arid coastal areas use mainly desalinated water for their domestic water demands, and treated wastewater for irrigating green areas. Private water companies supply these hotels with their domestic water needs. There is normally a contractual agreement stating a minimum requirement that has to be supplied by the water company and that the hotel management has to pay for regardless of its actual consumption ("contracted-for water supply"). This paper describes a model to determine what value a hotel should choose for its contracted-for water supply in order to minimize its total annual water costs. An example from an arid coastal tourism-dominated city is presented: Sharm El Sheikh, Egypt.The managers of hotels with expected high occupancy rates (74% and above) can contract for more than 80%. On the other hand, hotels with expected lower occupancy rates (60% and less) can contract for less than 70% of the peak daily domestic water demand. With a green area ratio of 40 m(2)/room or less, an on-site wastewater treatment plant can satisfy the required irrigation demand for an occupancy rate as low as 42%. Increasing the ratio of green irrigated area to 100 m(2)/room does not affect the contracted-for water supply at occupancy rates above 72%; at lower occupancy rates, however, on-site treated wastewater is insufficient for irrigating the green areas. Increasing the green irrigated area to 120 m(2)/room increases the need for additional water, either from externally sourced treated wastewater or potable water. The cost of the former is much lower than the latter (0.58 versus 1.52 to 2.14 US$/m(3) in the case study area).

  2. Barium transport in the hot spot region of fluorescent lamps

    International Nuclear Information System (INIS)

    Sigeneger, F; Rackow, K; Uhrlandt, D; Ehlbeck, J; Lieder, G

    2010-01-01

    The transport of barium atoms and ions in the vicinity of the hot spot in fluorescent lamps operating at 25 kHz is investigated by a combined experimental and theoretical approach. By laser-induced fluorescence, the particle densities of barium atoms and ions were measured time-resolved at different distances from the spot centre. In addition, the time-dependent cathode fall voltage was measured using an improved band method. The model combines a kinetic part for the electrons with a fluid part for the barium atoms and ions. Both parts are spatially resolved in spherically symmetric geometry. The space-dependent electron Boltzmann equation yields the electron density and the ionization rate coefficient of barium as functions of the cathode fall voltage. These results are used to solve the time-dependent particle balance equations of barium atoms and ions which include the ionization of barium as gain and loss terms, respectively. Good agreement between the measured and calculated particle densities of barium atoms is obtained. A sensitive dependence of the ionization frequency and of the barium particle densities on the cathode fall voltage was found.

  3. Monitoring and Analysing Land Use/Cover Changes in an Arid Region Based on Multi-Satellite Data: The Kashgar Region, Northwest China

    Directory of Open Access Journals (Sweden)

    Ayisulitan Maimaitiaili

    2018-01-01

    Full Text Available In arid regions, oases ecosystems are fragile and sensitive to climate change, and water is the major limiting factor for environmental and socio-economic developments. Understanding the drivers of land use/cover change (LUCC in arid regions is important for the development of management strategies to improve or prevent environmental deterioration and loss of natural resources. The Kashgar Region is the key research area in this study; it is a typical mountain-alluvial plain-oasis-desert ecosystem in an arid region, and is one of the largest oases in Xinjiang Uyghur Autonomous Region, China. In addition, the Kashgar Region is an important cotton and grain production area. This study’s main objectives are to quantify predominant LUCCs and identify their driving forces, based on the integration of multiple remote sensors and applications of environmental and socio-economic data. Results showed that LUCCs have been significant in the Kashgar Region during the last 42 years. Cultivated land and urban/built-up lands were the most changed land cover (LC, by 3.6% and 0.4% from 1972 to 10.2% and 3% in 2014, respectively. By contrast, water and forest areas declined. Grassland and snow-covered areas have fluctuated along with climate and human activities. Bare land was changed slightly from 1972 to 2014. According to the land use transfer matrix, cultivated land replaced grass- and forestland. Urban/built-up land mainly expanded over cultivated and bare land. LUCCs were triggered by the interplay of natural and social drivers. Increasing runoff, caused by regional climate changes in seasonal variation, and snow melt water, have provided water resources for LC changes. In the same way, population growth, changes in land tenure, and socio-economic development also induced LUCCs. However, expansion of cultivated land and urban/built-up land led to increased water consumption and stressed fragile water systems during on-going climate changes. Therefore

  4. Shallow Horizontal GCHP Effectiveness in Arid Climate Soils

    Science.gov (United States)

    North, Timothy James

    Ground coupled heat pumps (GCHPs) have been used successfully in many environments to improve the heating and cooling efficiency of both small and large scale buildings. In arid climate regions, such as the Phoenix, Arizona metropolitan area, where the air condi-tioning load is dominated by cooling in the summer, GCHPs are difficult to install and operate. This is because the nature of soils in arid climate regions, in that they are both dry and hot, renders them particularly ineffective at dissipating heat. The first part of this thesis addresses applying the SVHeat finite element modeling soft-ware to create a model of a GCHP system. Using real-world data from a prototype solar-water heating system coupled with a ground-source heat exchanger installed in Menlo Park, California, a relatively accurate model was created to represent a novel GCHP panel system installed in a shallow vertical trench. A sensitivity analysis was performed to evaluate the accuracy of the calibrated model. The second part of the thesis involved adapting the calibrated model to represent an ap-proximation of soil conditions in arid climate regions, using a range of thermal properties for dry soils. The effectiveness of the GCHP in the arid climate region model was then evaluated by comparing the thermal flux from the panel into the subsurface profile to that of the prototype GCHP. It was shown that soils in arid climate regions are particularly inefficient at heat dissipation, but that it is highly dependent on the thermal conductivity inputted into the model. This demonstrates the importance of proper site characterization in arid climate regions. Finally, several soil improvement methods were researched to evaluate their potential for use in improving the effectiveness of shallow horizontal GCHP systems in arid climate regions.

  5. Turbulent fluxes in atmospheric boundary layer of a semi-arid region of N-E Brazil

    International Nuclear Information System (INIS)

    Patel, S. R.; De Fatima Correia, M.; Da Silva, E. M.; Costa, A. M. N.

    2004-01-01

    The preliminary results of the Experiment 'Experimento de Microfisica de Nuvens-EmfiN' (Experiment of microphysics of clouds) conducted by Universidade Estatual de Ceara-UECE at Fortaleza, a semi-arid region of N-E Brazil, are presented. The mean kinematic fluxes of sensible heat and water vapor of the surface boundary layer are estimated by the thermodynamic energy and water vapor conservation equations; and by the Monin-Obukhov similarity theory. The results of the two methods are in good agreement. It is shown that in the absence of sophisticated fast-response turbulence instrumentation and wind data the conservations equations methods are better option for estimation of heat and water vapor fluxes. Further they are useful to study the turbulent fluxes in inhomogeneous condition in time like early morning and late evening boundary layer transitions

  6. Towards prediction of soil erodibility using hyperspectral information: a case study in a semi-arid region of Iran

    DEFF Research Database (Denmark)

    Ostovari, Yaser; Ghorbani-Dashtaki, Shoja; Bahrami, Hossein-Ali

    2018-01-01

    and develop Spectrotransfer Function (STF) using spectral reflectance information and Pedotransfer Function (PTF) to predict the K-factor, respectively. The derived STF was compared with developed PTF using measurable soil properties by Ostovari et al. (2016) and the Universal Soil Loss Equation (USLE......Soil Visible–Near-Infrared (Vis-NIR) spectroscopy has become an applicable and interesting technique to evaluate a number of soil properties because it is a fast, cost-effective, and non-invasive measurement technique. The main objective of the study to predict soil erodibility (K-factor), soil...... organic matter (SOM), and calcium carbonate equivalent (CaCO3) in calcareous soils of semi-arid regions located in south of Iran using spectral reflectance information in the Vis-NIR range. The K-factor was measured in 40 erosion plots under natural rainfall and the spectral reflectance of soil samples...

  7. Food resources used by three species of fish in the semi-arid region of Brazil

    Directory of Open Access Journals (Sweden)

    Márcio J. da Silva

    2010-01-01

    Full Text Available Temporary and semi-permanent aquatic habitats in semi-arid Brazil have been reported as important sites supporting a diverse fish fauna. As such, they must be able to trophically sustain fish species that feed at different trophic levels. This study aims to describe the diets of Astyanax aff. bimaculatus, Hoplias malabaricus and Prochilodus brevis in aquatic systems in semi-arid Brazil, providing evidence of the importance of these habitats as supporters of large consumers like fish. The diet of the three species studied was diverse, feeding on a range of food items, from microalgae to fish. Despite that, a few items were more important to each of the study species. These results and the relatively high rates of stomach fullness indicate that a diverse and abundant food range is available in the study sites, but species seem to select some food resources. The present study provides evidence that despite being highly variable, intermittent and semi-permanent aquatic systems in semi-arid Brazil are able to trophically sustain large consumers.Os ambientes aquáticos temporários e semi-permanentes do semiárido brasileiro tem sido mostrados como importantes sítios que possuem uma diversa fauna de peixes. Desta forma, esses ambientes devem ser capazes de sustentar, do ponto de vista trófico, populações de peixes que se alimentam em diversos níveis tróficos. O presente estudo tem como objetivo descrever o hábito alimentar de Astyanax aff. bimaculatus, Hoplias malabaricus e Prochilodus brevis em ambientes aquáticos do semiárido brasileiro, fornecendo evidências da importância desses habitats para manutenção da diversidade de consumidores como os peixes. A composição da dieta das espécies estudadas foi diversificada, já que alimentaram-se de uma variedade de classes de itens, desde microalgas até peixes. Apesar disso, alguns itens foram mais importantes para cada uma das três espécies. Estes resultados, e as altas taxas de reple

  8. Exploiting the synergy between SMAP and SMOS to improve brightness temperature simulations and soil moisture retrievals in arid regions

    Science.gov (United States)

    Ebrahimi, Mohsen; Alavipanah, Seyed Kazem; Hamzeh, Saeid; Amiraslani, Farshad; Neysani Samany, Najmeh; Wigneron, Jean-Pierre

    2018-02-01

    The objective of this study was to exploit the synergy between SMOS and SMAP based on vegetation optical depth (VOD) to improve brightness temperature (TB) simulations and land surface soil moisture (SM) retrievals in arid regions of the world. In the current operational algorithm of SMAP (level 2), vegetation water content (VWC) is considered as a proxy to compute VOD which is calculated by an empirical conversion function of NDVI. Avoiding the empirical estimation of VOD, the SMOS algorithm is used to retrieve simultaneously SM and VOD from TB observations. The present study attempted to improve SMAP TB simulations and SM retrievals by benefiting from the advantages of the SMOS (L-MEB) algorithm. This was achieved by using a synergy method based on replacing the default value of SMAP VOD with the retrieved value of VOD from the SMOS multi angular and bi-polarization observations of TB. The insitu SM measurements, used as reference SM in this study, were obtained from the International Soil Moisture Network (ISMN) over 180 stations located in arid regions of the world. Furthermore, four stations were randomly selected to analyze the temporal variations in VOD and SM. Results of the synergy method showed that the accuracy of the TB simulations and SM retrievals was respectively improved at 144 and 124 stations (out of a total of 180 stations) in terms of coefficient of determination (R2) and unbiased root mean squared error (UbRMSE). Analyzing the temporal variations in VOD showed that the SMOS VOD, conversely to the SMAP VOD, can better illustrate the presence of herbaceous plants and may be a better indicator of the seasonal changes in the vegetation density and biomass over the year.

  9. Asymmetry of agricultural water consumption in arid regions during alternating decadal scale wet and dry periods: explanation using behavioral economics

    Science.gov (United States)

    Tian, Fuqiang

    2017-04-01

    Increase of human water consumption for agriculture and consequent degradation of the ecological environment is a common feature in many arid regions. Understanding the driving mechanisms behind this phenomenon is of critical importance for regional sustainable development. In this study, analyses of temporal patterns of human water consumption are carried out in three hyper-arid inland basins, i.e., Aral Sea Basin in Central Asia, and the Tarim and Heihe River Basins in Northwestern China. Multi-decadal time series of hydrological and human consumption data are divided into decadal sequences of wet and dry years. During the wet phases, the greater water availability inspires economic expansion and human water consumption experiences growth at a rate faster than that of incoming water. During the dry phases, however, the expanded economy (e.g., irrigation land expansion in an agriculture-based economy) has been managed to sustain or even to increase production by over-exploitation of water with sophisticated technologies. Inability to reduce human water consumption at a rate commensurate with the decrease of incoming water supply leads to serious ecosystem degradation. This asymmetric human water consumption response of society to decadal scale hydrologic variability can be explained in terms of prospect theory drawn from behavioral economics, which states that people tend to be risk averse when facing gains and show risk preference when facing losses. In the three socio-hydrological case studies, direct economic gain/loss has relatively low value but high certainty when compared to indirect economic loss/gain (such as environmental or sustainability loss/gain), which has high value but with high uncertainty. According to prospect theory, people tend to gain direct economic benefits at the expense of environmental degradation and at the risk of system collapse. The outcomes of this study have major implications for water resources management at long time scales

  10. Land Surface Temperature Retrieval from MODIS Data by Integrating Regression Models and the Genetic Algorithm in an Arid Region

    Directory of Open Access Journals (Sweden)

    Ji Zhou

    2014-06-01

    Full Text Available The land surface temperature (LST is one of the most important parameters of surface-atmosphere interactions. Methods for retrieving LSTs from satellite remote sensing data are beneficial for modeling hydrological, ecological, agricultural and meteorological processes on Earth’s surface. Many split-window (SW algorithms, which can be applied to satellite sensors with two adjacent thermal channels located in the atmospheric window between 10 μm and 12 μm, require auxiliary atmospheric parameters (e.g., water vapor content. In this research, the Heihe River basin, which is one of the most arid regions in China, is selected as the study area. The Moderate-resolution Imaging Spectroradiometer (MODIS is selected as a test case. The Global Data Assimilation System (GDAS atmospheric profiles of the study area are used to generate the training dataset through radiative transfer simulation. Significant correlations between the atmospheric upwelling radiance in MODIS channel 31 and the other three atmospheric parameters, including the transmittance in channel 31 and the transmittance and upwelling radiance in channel 32, are trained based on the simulation dataset and formulated with three regression models. Next, the genetic algorithm is used to estimate the LST. Validations of the RM-GA method are based on the simulation dataset generated from in situ measured radiosonde profiles and GDAS atmospheric profiles, the in situ measured LSTs, and a pair of daytime and nighttime MOD11A1 products in the study area. The results demonstrate that RM-GA has a good ability to estimate the LSTs directly from the MODIS data without any auxiliary atmospheric parameters. Although this research is for local application in the Heihe River basin, the findings and proposed method can easily be extended to other satellite sensors and regions with arid climates and high elevations.

  11. Untangling the effects of shallow groundwater and deficit irrigation on irrigation water productivity in arid region: New conceptual model.

    Science.gov (United States)

    Xue, Jingyuan; Huo, Zailin; Wang, Fengxin; Kang, Shaozhong; Huang, Guanhua

    2018-04-01

    Water scarcity and salt stress are two main limitations for agricultural production. Groundwater evapotranspiration (ET g ) with upward salt movement plays an important role in crop water use and water productivity in arid regions, and it can compensate the impact of deficit irrigation on crop production. Thus, comprehensive impacts of shallow groundwater and deficit irrigation on crop water use results in an improvement of irrigation water productivity (IWP). However, it is difficult to quantify the effects of groundwater and deficit irrigation on IWP. In this study, we built an IWP evaluation model coupled with a water and salt balance model and a crop yield estimation model. As a valuable tool of IWP simulation, the calibrated model was used to investigate the coupling response of sunflower IWP to irrigation water depths (IWDs), groundwater table depth (GTDs) and groundwater salinities (GSs). A total of 210 scenarios were run in which five irrigation water depths (IWDs) and seven groundwater table depths (GTDs) and six groundwater salinities (GSs) were used. Results indicate that increasing GS clearly increases the negative effect on a crop's actual evapotranspiration (ET a ) as salt accumulation in root zone. When GS is low (0.5-1g/L), increasing GTD produces more positive effect than negative effect. In regard to relatively high GS (2-5g/L), the negative effect of shallow-saline groundwater reaches a maximum at 2m GTD. Additionally, the salt concentration in the root zone maximizes its value at 2.0m GTD. In most cases, increasing GTD and GS reduces the benefits of irrigation water and IWP. The IWP increases with decreasing irrigation water. Overall, in arid regions, capillary rise of shallow groundwater can compensate for the lack of irrigation water and improve IWP. By improving irrigation schedules and taking advantages of shallow saline groundwater, we can obtain higher IWP. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Evaluation of Warm Season Turfgrass under Different Irrigation Regimes in Arid Region

    Directory of Open Access Journals (Sweden)

    Abdullah Mohd Hassan ALSHEHHI

    2010-09-01

    Full Text Available Turfgrasses play a very important role in enhancing quality of life in modern urban living. Water quantity is the most important challenge worldwide in establishing and maintaining quality turf. The present study was aimed to test the performance of three warm season turfgrasses under four water levels for plantation in arid zones. Pits (48 measuring 1m length x 1m width x 0.6 m depth were planted with four replications of Common Bermuda grass (Cynodon dactylon, Tifway Bermuda grass (Cynodon dactylon x transvaalensis and Seashore Paspalum grass (Paspalum vaginatum in complete randomized design (CRD. Irrigation was done daily with 15 l/plot during the first 4 weeks (establishment period and four irrigation levels (5, 10, and 15, 20 l/lot were maintained in the following 8 weeks (treatment period. Physical parameters (canopy temperatures, ambient temperature, leaf area, shoot production and relative water content were measured once in two week as well as the visual quality (shoot color, shoot density and shoot uniformity was assessed, however, chlorophyll analysis was done in the end of the study. It was found that temperature has significant effect on performance of turfgrasses. Canopy temperature was higher than ambient temperature in the three turfgrasses but it has different level in each variety. Five liter of water per day per square meter gave acceptable turf quality when ambient temperature ranged from 20 to 33�C. Seashore paspalum performed best followed by Tifway Bermuda grass and common Bermuda grass respectively.

  13. Monoterpene emissions from Pinus halepensis forests in a semi-arid region (Israel)

    Science.gov (United States)

    Seco, R.; Karl, T.; Turnipseed, A. A.; Greenberg, J.; Guenther, A. B.; Llusia, J.; Penuelas, J.; Kim, S.; Dicken, U.; Rotenberg, E.; Rohatyn, S.; Preisler, Y.; Yakir, D.

    2013-12-01

    Atmospheric volatile organic compounds (VOCs) have key environmental and biological roles, and can affect atmospheric chemisty, secondary aerosol formation, and as a consequence also climate. At the same time, global changes in climate arising from human activities can modify the VOC emissions of vegetation in the coming years. Monoterpene emission fluxes were measured during April 2013 at two forests in the semi-arid climate of Israel. Both forests were dominated by the same pine species, Pinus halepensis, but differed in the amount of annual average precipitation received (280 and 800 mm at Yatir and Birya, respectively). Measurements performed included leaf-level sampling as well as canopy-level flux calculations. Leaf level monoterpene emissions were sampled from leaf cuvettes with adsorbent cartridges and later analyzed by GC-MS. Canopy scale fluxes were calculated with the Disjunct Eddy Covariance technique by means of a Quadrupole PTRMS. We report the differences observed between the two forests in terms of photosynthetic activity and monoterpene emissions, aiming to see the effect of the different precipitation regimes at each location.

  14. Variation of NEE and its affecting factors in a vineyard of arid region of northwest China

    Science.gov (United States)

    Guo, W. H.; Kang, S. Z.; Li, F. S.; Li, S. E.

    2014-02-01

    To understand the variation of net ecosystem CO2 exchange (NEE) in orchard ecosystem and it's affecting factors, carbon flux was measured using eddy covariance system in a wine vineyard in arid northwest China during 2008-2010. Results show that vineyard NEE was positive value at the early growth stage, higher negative value at the mid-growth stage, and lower negative value at the later growth stage. Diurnal variation of NEE was "W" shaped curve in sunny day, but "U" shaped curve in cloudy day. Irrigation and pruning did not affect diurnal variation shape of NEE, however, irrigation reduced the difference between maximal and minimal value of NEE and pruning reduced the carbon sink capacity. The main factors affecting hourly NEE were canopy conductance (gc) and net radiation (Rn). The hourly NEE increased with the increase of gc or Rn when gc was less than 0.02 m·s-1 or Rn was between 0 and 200 W·m-2. The main factors affecting both daily and seasonal NEE were gc, air temperature (Ta), atmospheric CO2 density, vapour pressure deficit (VPD) and soil moisture content.

  15. Extracting Vegetation Coverage in Dry-hot Valley Regions Based on Alternating Angle Minimum Algorithm

    Science.gov (United States)

    Y Yang, M.; Wang, J.; Zhang, Q.

    2017-07-01

    Vegetation coverage is one of the most important indicators for ecological environment change, and is also an effective index for the assessment of land degradation and desertification. The dry-hot valley regions have sparse surface vegetation, and the spectral information about the vegetation in such regions usually has a weak representation in remote sensing, so there are considerable limitations for applying the commonly-used vegetation index method to calculate the vegetation coverage in the dry-hot valley regions. Therefore, in this paper, Alternating Angle Minimum (AAM) algorithm of deterministic model is adopted for selective endmember for pixel unmixing of MODIS image in order to extract the vegetation coverage, and accuracy test is carried out by the use of the Landsat TM image over the same period. As shown by the results, in the dry-hot valley regions with sparse vegetation, AAM model has a high unmixing accuracy, and the extracted vegetation coverage is close to the actual situation, so it is promising to apply the AAM model to the extraction of vegetation coverage in the dry-hot valley regions.

  16. Spatial and temporal variability in the Quality of Surface water in a semi-arid mediterranean region (river orontes- Lebanon)

    International Nuclear Information System (INIS)

    SLIM, K.; SAAD, Z.; KAZPARD, V.; EL SAMAD, O.; NASREDDINE, M.

    2004-01-01

    The Orontes River is an international river, with its headwaters in Lebanon, its middle section in Syria and its mouth in Turkey. Fresh surface waters were sampled monthly during the year 2000 and analyzed for major ions and for trace metals. Sea-salt aerosols in rainwater partially influence the major ion composition in the river. The concentration of major cations and anions fall within the range of the most common natural Concentration of major ion assemblages established for world river(MCNC), with a cation and anion dominance in the order of Ca > Mg > Na> K and HCO3 > SO4 > Cl, which tend to be predominantly influenced by chemical weathering of rocks and minerals in a semi-arid region. Ca and HCO3 are mostly derived from the dissolution of carbonate rocks. The sources of SO4 could be attributed to anhydrite minerals and to anthropogenic impact from fertilizers. Increases in nutrient concentrations are attributed mainly to the increasing influence of agricultural runoff. δ18 0/ δH plots shows that the data either fits the Mediterranean Meteoric Water Line(MMWL) or have elevated values that indicate evaporative isotope enrichment in a semi-arid climate. The correlation matrix for trace elements shows a high coefficient of correlation for Fe, Zn and Cu indicating that these elements could be controlled by the same chemistry in water. The bicarbonate-alkaline type of Orontes surface water contribute to the formation of trace metals-carbonate complexes such as FeCO3(aq) and ZnCO3 (aq). The good correlation between Pb, Cd and Cr reflects the effect of increasing urbanization in the catchments. (author)

  17. Linking Bayesian and agent-based models to simulate complex social-ecological systems in semi-arid regions

    Directory of Open Access Journals (Sweden)

    Aloah J Pope

    2015-08-01

    Full Text Available Interdependencies of ecologic, hydrologic, and social systems challenge traditional approaches to natural resource management in semi-arid regions. As a complex social-ecological system, water demands in the Sonoran Desert from agricultural and urban users often conflicts with water needs for its ecologically-significant riparian corridors. To explore this system, we developed an agent-based model to simulate complex feedbacks between human decisions and environmental conditions in the Rio Sonora Watershed. Cognitive mapping in conjunction with stakeholder participation produced a Bayesian model of conditional probabilities of local human decision-making processes resulting to changes in water demand. Probabilities created in the Bayesian model were incorporated into the agent-based model, so that each agent had a unique probability to make a positive decision based on its perceived environment at each point in time and space. By using a Bayesian approach, uncertainty in the human decision-making process could be incorporated. The spatially-explicit agent-based model simulated changes in depth-to-groundwater by well pumping based on an agent’s water demand. Changes in depth-to-groundwater feedback to influence agent behavior, as well as determine unique vegetation classes within the riparian corridor. Each vegetation class then provides varying stakeholder-defined quality values of ecosystem services. Using this modeling approach allowed us to examine effects on both the ecological and social system of semi-arid riparian corridors under various scenarios. The insight provided by the model contributes to understanding how specific interventions may alter the complex social-ecological system in the future.

  18. Utilization of Indigenous Technical Knowledge (ITK'S) in Arid and Semi-Arid Regions of Eastern Kenya: A Coping Strategy to Shocks of Market Utilization

    International Nuclear Information System (INIS)

    Ndubi, J

    2002-01-01

    Most of the farmers in the arid and semi arid are poorly endowed with resources. Market liberalisation and withdrawal of government support (subsidies) in accessing some of the modern technologies has led to decreased use of most of the modern recommended technologies due to their high prices. A a coping strategy most of the resources poor farmers have turned to utilization of the indigenous technology to sustain their agricultural production. The main objective of this paper is to document the indigenous technologies utilized by farmers, explore the possibility of refining/calibrating and up-scaling them and the advantages and disadvantages of utilizing them as identified by the farmers. The method for data collection was by use of interviews the farmers who were stratified in terms of gender and age sets (young, middle aged and old) and data analysed by use of qualitative methods. The results indicate that, most farmers do utilize indigenous technology in crops, livestock pests, diseases, soil and water conservation as cropping strategies to increase input prices due to market liberalization and withdrawal of government subsidies. It was also observed that, there is need for scientists to calibrate the most important practices for improved adoption and up-scaling of the main indigenous technologies within and outside the study areas

  19. Oasis Irrigation-Induced Hydro-Climatic Effects: A Case Study in the Hyper-Arid Region of Northwest China

    Directory of Open Access Journals (Sweden)

    Nan Shan

    2018-04-01

    Full Text Available The response of potential evapotranspiration (ET0 to widespread irrigation is important to fully understand future regional climate changes and to infer adaptive management of agricultural water resources. The quantitative impact of irrigation on ET0 from 1960 to 2013 was evaluated using historical time series data of daily meteorological observations in the hyper-arid region of northwest China. The decreasing trends in ET0 were accelerated for meteorological stations in regions with oasis agriculture, especially in the summer and during the growing season. Irrigation led to a cooling effect on temperature, increased relative humidity and precipitation. All of these changes contributed to a larger decrease of ET0 trend. The findings of this study advance our insight into the effects of irrigation on dynamics in ET0 and meteorological factors. Further investigations to understand how ET0 responds to climate change and agricultural irrigation could provide guidance for determining effective measures of water resources for adapting to global change.

  20. Spatiotemporal changes in vegetation net primary productivity in the arid region of Northwest China, 2001 to 2012

    Science.gov (United States)

    Li, Zhen; Pan, Jinghu

    2018-03-01

    Net primary productivity (NPP) is recognized as an important index of ecosystem conditions and a key variable of the terrestrial carbon cycle. It also represents the comprehensive effects of climate change and anthropogenic activity on terrestrial vegetation. In this study, the temporal-spatial pattern of NPP for the period 2001-2012 was analyzed using a remote sensing-based carbon model (i.e., the Carnegie-Ames-Stanford Approach, CASA) in addition to other methods, such as linear trend analysis, standard deviation, and the Hurst index. Temporally, NPP showed a significant increasing trend for the arid region of Northwest China (ARNC), with an annual increase of 2.327 g C. Maximum and minimum productivity values appeared in July and December, respectively. Spatially, the NPP was relatively stable in the temperate and warm-temperate desert regions of Northwest China, while temporally, it showed an increasing trend. However, some attention should be given to the northwestern warm-temperate desert region, where there is severe continuous degradation and only a slight improvement trend.

  1. Analysis and evaluation of tillage on an alfisol in a semi-arid tropical region of India

    NARCIS (Netherlands)

    Klaij, M.C.

    1983-01-01

    Tillage field experiments were conducted on Alfisols in a semi-arid tropical environment in India. The research was conducted within the framework of the Farming Systems Research Program of the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT).

    To put the

  2. Regional differences in the surface temperature of Naked Neck laying hens in a semi-arid environment.

    Science.gov (United States)

    de Souza, João Batista Freire; de Arruda, Alex Martins Varela; Domingos, Hérica Girlane Tertulino; de Macedo Costa, Leonardo Lelis

    2013-05-01

    The aim of this study was to evaluate the regional differences in the surface temperature of Naked Neck hens that were subjected to different temperatures in a semi-arid environment. The surface temperature was measured in four body regions (face, neck, legs and feathered area) of 60 Naked Neck hens. The following environmental variables were measured at the center of the shed: the black globe temperature (T G ), air temperature (T A ), wind speed (U) and relative humidity (R H ). The T A was divided into three classes: 1 (24.0-26.0 °C), 2 (26.1-28.9 °C) and 3 (29.0-31.0 °C). An analysis of variance was performed by the least squares method and a comparison of the means by the Tukey-Kramer test. The results showed a significant effect of T A class, the body region and the interaction between these two effects on the surface temperature. There was no significant difference between the T A classes for the face and neck. The legs and feathered area showed significant differences between the T A classes. Regarding the effect of body regions within each T A class, there was a significant difference among all regions in the three T A classes. In all T A classes the neck had the highest average followed by the face and legs. The feathered area showed the lowest average of the different T A classes. In conclusion, this study showed that there are regional differences in the surface temperature of Naked Neck hens, with the legs acting as thermal windows.

  3. Challenges to estimate surface- and groundwater flow in arid regions: the Dead Sea catchment.

    Science.gov (United States)

    Siebert, Christian; Rödiger, Tino; Mallast, Ulf; Gräbe, Agnes; Guttman, Joseph; Laronne, Jonathan B; Storz-Peretz, Yael; Greenman, Anat; Salameh, Elias; Al-Raggad, Marwan; Vachtman, Dina; Zvi, Arie Ben; Ionescu, Danny; Brenner, Asher; Merz, Ralf; Geyer, Stefan

    2014-07-01

    The overall aim of the this study, which was conducted within the framework of the multilateral IWRM project SUMAR, was to expand the scientific basement to quantify surface- and groundwater fluxes towards the hypersaline Dead Sea. The flux significance for the arid vicinity around the Dead Sea is decisive not only for a sustainable management in terms of water availability for future generations but also for the resilience of the unique ecosystems along its coast. Coping with different challenges interdisciplinary methods like (i) hydrogeochemical fingerprinting, (ii) satellite and airborne-based thermal remote sensing, (iii) direct measurement with gauging station in ephemeral wadis and a first multilateral gauging station at the river Jordan, (iv) hydro-bio-geochemical approach at submarine and shore springs along the Dead Sea and (v) hydro(geo)logical modelling contributed to the overall aim. As primary results, we deduce that the following: (i) Within the drainage basins of the Dead Sea, the total mean annual precipitation amounts to 300 mm a(−1) west and to 179 mm a(−1) east of the lake, respectively. (ii) The total mean annual runoff volumes from side wadis (except the Jordan River) entering the Dead Sea is approximately 58–66 × 10(6) m(3) a(−1) (western wadis: 7–15 × 10(6) m(3) a(−1); eastern wadis: 51 × 10(6) m(3) a(−1)). (iii) The modelled groundwater discharge from the upper Cretaceous aquifers in both flanks of the Dead Sea towards the lake amounts to 177 × 10(6) m(3) a(−1). (iv) An unexpected abundance of life in submarine springs exists, which in turn explains microbial moderated geo-bio-chemical processes in the Dead Sea sediments, affecting the highly variable chemical composition of on- and offshore spring waters.The results of this work show a promising enhancement of describing and modelling the Dead Sea basin as a whole. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Co-occurrence of arsenic and fluoride in groundwater of semi-arid regions in Latin America: genesis, mobility and remediation.

    Science.gov (United States)

    Alarcón-Herrera, María Teresa; Bundschuh, Jochen; Nath, Bibhash; Nicolli, Hugo B; Gutierrez, Melida; Reyes-Gomez, Victor M; Nuñez, Daniel; Martín-Dominguez, Ignacio R; Sracek, Ondra

    2013-11-15

    Several million people around the world are currently exposed to excessive amounts of arsenic (As) and fluoride (F) in their drinking water. Although the individual toxic effects of As and F have been analyzed, there are few studies addressing their co-occurrences and water treatment options. Several studies conducted in arid and semi-arid regions of Latin America show that the co-occurrences of As and F in drinking water are linked to the volcaniclastic particles in the loess or alluvium, alkaline pH, and limited recharge. The As and F contamination results from water-rock interactions and may be accelerated by geothermal and mining activities, as well as by aquifer over-exploitation. These types of contamination are particularly pronounced in arid and semi-arid regions, where high As concentrations often show a direct relationship with high F concentrations. Enrichment of F is generally related to fluorite dissolution and it is also associated with high Cl, Br, and V concentrations. The methods of As and F removal, such as chemical precipitation followed by filtration and reverse osmosis, are currently being used at different scales and scenarios in Latin America. Although such technologies are available in Latin America, it is still urgent to develop technologies and methods capable of monitoring and removing both of these contaminants simultaneously from drinking water, with a particular focus towards small-scale rural operations. Copyright © 2012 Elsevier B.V. All rights reserved.

  5. Simulated biomass, environmental impacts and best management practices for long-term switchgrass systems in a semi-arid region

    International Nuclear Information System (INIS)

    Wang, Limei; Qian, Yaling; Brummer, Joe E.; Zheng, Jiyong; Wilhelm, Sarah; Parton, William J.

    2015-01-01

    Long-term information on switchgrass (Panicum virgatum L.) as a biomass energy crop grown on marginally saline soil and the associated impacts on soil carbon (C) and nitrogen (N) dynamics, greenhouse gas (GHG) emissions, and best management practices (BMPs) are limited. In this study, we employed the DAYCENT model, based on a 4-year switchgrass field experiment, to evaluate the long-term biomass yield potential and environmental impacts, and further to develop BMPs for switchgrass in a semi-arid region. The model showed that long-term (14-year) annual mean biomass yields were 9.6 and 5.2 Mg ha −1 for irrigated and rainfed switchgrass systems, respectively. The simulated biomass yields correlated well with field-measured biomass with r 2 values of 0.99 and 0.89 for irrigated and rainfed systems, respectively. Soil organic carbon (SOC) and soil total nitrogen (STN) accumulated rapidly after switchgrass establishment, with mean accrual rates of 0.99–1.13 Mg C ha −1  yr −1 and 0.04–0.08 Mg N ha −1  yr −1 , respectively. Based on the outputs of numerous long-term model simulations with variable irrigation water supplies and N rates, the irrigation regime and N rate with the highest yield to input ratio were chosen as BMPs. The DAYCENT model predicted-BMP was irrigating every 14 days at 70% potential evapotranspiration combined with an N rate of 67 kg ha −1  yr −1 . Switchgrass established and produced biomass reasonably well in this semi-arid region; however, appropriate irrigation and N fertilization were needed for optimal biomass yield. Switchgrass had a great potential to sequester C into soils with low N 2 O emissions while supplying significant quantities of biomass for biofuel synthesis. - Highlights: • The DAYCENT model reliably simulated the growth of switchgrass on marginal land. • Long-term biomass and environmental impacts were simulated using the DAYCENT model. • Switchgrass produced biomass well on marginal land, but

  6. Spatial and temporal variability of drought in the arid region of China and its relationships to teleconnection indices

    Science.gov (United States)

    Wang, Huaijun; Chen, Yaning; Pan, Yingping; Li, Weihong

    2015-04-01

    We studied the drought patterns in the arid region of northwestern China between 1960 and 2010 using the Palmer Drought Severity Index (PDSI). The general evolution of drought was obtained by empirical orthogonal function (EOF), rotated empirical orthogonal function (REOF), the Mann-Kendall test, and the continuous wavelet transform method. Additionally, relationships between rotated principal component time series (RPCs) and seven selected climate indices were analyzed. The results showed that: (1) Four moisture-related spatial patterns (North Xinjiang, western South Xinjiang, Central Xinjiang, and the Hexi Corridor) were objectively defined by REOF analysis. These patterns are related to distinct geographical areas and are associated with distinct temporal variations. (2) The PDSI increased significantly in most regions of Xinjiang, while decreased in the eastern Hexi Corridor. The significant 4-8 year band is the major period band for the annual and seasonal PDSI derived. (3) The seasonal REOFs (RPCs) and EOFs (PCs) have consistent spatial distribution patterns with the annual REOF. The seasonal trends of PDSI are also the same as the annual PDSI trends, indicating space-time consistency between annual PDSI and seasonal PDSI. (4) The drought evolution in this region is affected by the area of northern hemisphere polar vortex, the Arctic Oscillation, and the North Atlantic Oscillation. In addition, the changes of drought in South Xinjiang and the Hexi Corridor may also be associated with the Tibetan Plateau High. Changes in drought pattern are expected to have a strong impact on the economic livelihood of the region, especially for agricultural production.

  7. Hydrological differentiation and spatial distribution of high altitude wetlands in a semi-arid Andean region derived from satellite data

    Science.gov (United States)

    Otto, M.; Scherer, D.; Richters, J.

    2011-05-01

    High Altitude Wetlands of the Andes (HAWA) belong to a unique type of wetland within the semi-arid high Andean region. Knowledge about HAWA has been derived mainly from studies at single sites within different parts of the Andes at only small time scales. On the one hand, HAWA depend on water provided by glacier streams, snow melt or precipitation. On the other hand, they are suspected to influence hydrology through water retention and vegetation growth altering stream flow velocity. We derived HAWA land cover from satellite data at regional scale and analysed changes in connection with precipitation over the last decade. Perennial and temporal HAWA subtypes can be distinguished by seasonal changes of photosynthetically active vegetation (PAV) indicating the perennial or temporal availability of water during the year. HAWA have been delineated within a region of 12 800 km2 situated in the Northwest of Lake Titicaca. The multi-temporal classification method used Normalized Differenced Vegetation Index (NDVI) and Normalized Differenced Infrared Index (NDII) data derived from two Landsat ETM+ scenes at the end of austral winter (September 2000) and at the end of austral summer (May 2001). The mapping result indicates an unexpected high abundance of HAWA covering about 800 km2 of the study region (6 %). Annual HAWA mapping was computed using NDVI 16-day composites of Moderate Resolution Imaging Spectroradiometer (MODIS). Analyses on the relation between HAWA and precipitation was based on monthly precipitation data of the Tropical Rain Measurement Mission (TRMM 3B43) and MODIS Eight Day Maximum Snow Extent data (MOD10A2) from 2000 to 2010. We found HAWA subtype specific dependencies on precipitation conditions. A strong relation exists between perennial HAWA and snow fall (r2: 0.82) in dry austral winter months (June to August) and between temporal HAWA and precipitation (r2: 0.75) during austral summer (March to May). Annual changes in spatial extend of perennial HAWA

  8. The Impact of Climate Change on Raw and Untreated Wastewater Use for Agriculture, Especially in Arid Regions: A Review.

    Science.gov (United States)

    Faour-Klingbeil, Dima; Todd, Ewen C D

    2018-02-01

    Climate change is one of the major challenges of our time that pose unprecedented stress to the environment and threats to human health. The global impacts of climate change are vast, spanning from extreme weather events to changes in patterns and distribution of infectious diseases. Lack of rainfall associated with higher temperatures has a direct influence on agricultural production. This is compounded by a growing population forecasted to expand further with increasing needs for food and water. All this has led to the increasing use of wastewater worldwide. In this review, we more specifically discuss the use of untreated wastewater in agriculture in the Middle East and North Africa (MENA) countries, the most arid region in the world. This presents challenges for agriculture with respect to water availability and increasing wastewater use in agri-food chain. This in turn exerts pressures on the safety of food raised from such irrigated crops. Current practices in the MENA region indicate that ineffective water resource management, lack of water quality policies, and slow-paced wastewater management strategies continue to contribute to a decline in water resources and an increased unplanned use of black and graywater in agriculture. Radical actions are needed in the region to improve water and wastewater management to adapt to these impacts. In this regard, the 2006 WHO guidelines for the use of wastewater contain recommendations for the most effective solutions. They provide a step-by-step guide for series of appropriate health protection measures for microbial reduction targets of 6 log units for viral, bacterial, and protozoan pathogens, but these need to be combined with new varieties of crops that are drought and pest resistant. More research into economic local treatment procedures for wastewater in the region is warranted.

  9. Hydrological response to land cover changes and human activities in arid regions using a geographic information system and remote sensing.

    Directory of Open Access Journals (Sweden)

    Shereif H Mahmoud

    Full Text Available The hydrological response to land cover changes induced by human activities in arid regions has attracted increased research interest in recent decades. The study reported herein assessed the spatial and quantitative changes in surface runoff resulting from land cover change in the Al-Baha region of Saudi Arabia between 1990 and 2000 using an ArcGIS-surface runoff model and predicted land cover and surface runoff depth in 2030 using Markov chain analysis. Land cover maps for 1990 and 2000 were derived from satellite images using ArcGIS 10.1. The findings reveal a 26% decrease in forest and shrubland area, 28% increase in irrigated cropland, 1.5% increase in sparsely vegetated land and 0.5% increase in bare soil between 1990 and 2000. Overall, land cover changes resulted in a significant decrease in runoff depth values in most of the region. The decrease in surface runoff depth ranged from 25-106 mm/year in a 7020-km2 area, whereas the increase in such depth reached only 10 mm/year in a 243-km2 area. A maximum increase of 73 mm/year was seen in a limited area. The surface runoff depth decreased to the greatest extent in the central region of the study area due to the huge transition in land cover classes associated with the construction of 25 rainwater harvesting dams. The land cover prediction revealed a greater than twofold increase in irrigated cropland during the 2000-2030 period, whereas forest and shrubland are anticipated to occupy just 225 km2 of land area by 2030, a significant decrease from the 747 km2 they occupied in 2000. Overall, changes in land cover are predicted to result in an annual increase in irrigated cropland and dramatic decline in forest area in the study area over the next few decades. The increase in surface runoff depth is likely to have significant implications for irrigation activities.

  10. Hot electron formation in thermal barrier region of tandem mirror GAMMA 10

    International Nuclear Information System (INIS)

    Katanuma, I.; Kiwamoto, Y.; Sawada, K.; Miyoshi, S.

    1987-01-01

    We have studied the hot electron build-up by the second harmonic electron cyclotron resonance heating in the thermal barrier region of tandem mirror GAMMA 10 by using a Fokker-Planck code with self-consistent potential profile taken into account. We have found two phases in the evolution of hot electron population and the potential profile. In the first phase where the RF diffusion is dominant quick increase of the hot electron density and that of the mean energy are observed. No further increase in the mean energy is observed thereafter. The potential is the deepest during the first phase. The second phase starts in the mean-free-time of the pitch angle scattering of hot electrons on cold electrons and ions. In this phase the hot electron population increases in the rate of the pitch angle scattering. The potential dip shallows due to the accumulation of pitch angle scattered passing ions. This observation indicates the necessity of the ion pumping for maintaining the negative potential at the thermal barrier. (author)

  11. Traditional uses of medicinal animals in the semi-arid region of northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Alves Rômulo Romeu Nóbrega

    2012-10-01

    Full Text Available Abstract The present work presents an inventory of the traditional medicinal uses of animals in the municipality of Bom Sucesso in Paraíba State (PB in the semiarid northeastern region of Brazil. Information was obtained through the use of semi-structured interviews with 50 people who use zootherapeutic products. A total of 25 animal species used for medicinal purposes were identified (18 vertebrates and seven invertebrates distributed among five taxonomic categories; the groups with the largest numbers of citations were: mammals (8 citations, insects (7, and reptiles (5. The most cited animal species were: Tubinambis merianae “teju” lizards (44 citations; Apis mellifera Italian honeybees (318 citations; Gallus gallus chickens (31 citations; Ovis aries sheep (31 citations; Crotalus durissus rattlesnakes (14 citations; Boa constrictor (12 citations; and Bos taurus cattle (12 citations. A significant number of illnesses and conditions treated with animal-based medicines were cited, and the category with the greatest number of citations was “problems affecting the respiratory system”. Our results suggest that the use of zootherapeutics in the region is persistent, and that knowledge about these curative practices is an integral part of the regional culture. As such, studies concerning the uses of zootherapeutics are important windows to understanding human/environmental/cultural interactions and a pathway to conciliating regional cultures with efforts to conserve the native fauna.

  12. Assess the potential of solar irrigation systems for sustaining pasture lands in arid regions - A case study in Northwestern China

    International Nuclear Information System (INIS)

    Yu, Yingdong; Liu, Jiahong; Wang, Hao; Liu, Miao

    2011-01-01

    Highlights: → We figured out the appropriate indicators for solar irrigation. → We analyzed the economic benefits of solar irrigation system. → The geographic allocation of grasslands suitable for solar irrigation in Qinghai province is presented. → The appropriate region for solar irrigation is also discussed. → The problems and countermeasures of PV pumping irrigation are considered. - Abstract: The combined impact of global climate change and increasing human activities has led to the severe deterioration of grasslands in China. Using the solar irrigation systems is an effective way for sustaining pasture lands in arid regions. A solar irrigation system is the device that uses the solar cell from the sun's radiation to generate electricity for driving the pump. And photovoltaic pump consists of an array of photovoltaic cells and pumps water from a well or reservoir for irrigation. Although ecologists and organizations constantly work and find ways to conserve grasslands through irrigation systems that use solar energy, issues on water resources are not yet thoroughly discussed. This paper takes into account the main factors in the study of water resources, including precipitation and groundwater, to analyze the feasibility of using a photovoltaic (PV) pumping irrigation. The appropriate area for such a PV pumping irrigation in Qinghai Province is also presented. The results show that the grasslands appropriate for PV pumping cover about 8.145 million ha, accounting for 22.3% of the grasslands in the entire province. Finally, the problems and countermeasures of PV pumping irrigation, including the impact on regional water balance, groundwater level and highland permafrost, are also considered.

  13. Influence of climate change and human activity on water resources in arid region of Northwest China: An overview

    Directory of Open Access Journals (Sweden)

    Yu-Jie Wang

    2017-12-01

    Full Text Available This study reviews the latest progress in research on climate change and water resources in the arid region of Northwest China, analyzes the cause of water resource changes within the region from the perspective of climate change and human activities, and summarizes future likely changes in water resources and associated adaptation strategies. The research shows that the climate in the region has experienced warming and wetting with the most significant warming in winter and the highest increase in summer precipitation since 1961. Areas with the most significant warming trends include the Qaidam Basin, the Yili River Valley, and Tacheng. Spatially, the increasing trend in precipitation becomes increasingly significant from the southeast to the northwest, and northern Xinjiang experienced the highest increase. Studies have shown a decrease in headwater of Shiyang River because runoff is mainly based on precipitation which shows a decrease trend. But an increase in western rivers was observed such as Tarim River and Shule River as well as Heihe River due to rapid glacier shrinkage and snowmelt as well as precipitation increase in mountain area. Meanwhile unreasonable human activities resulted in decrease of runoff in the middle and lower reaches of Haihe River, Shiyang River and Kaidu River. Finally, recommendations for future studies are suggested that include characteristics of changes in extreme weather events and their impacts on water resources, projections of future climate and water resource changes, climate change attribution, the selection of adaptation strategies relating to climate change and social economic activities, and use of scientific methods to quantitatively determine water resource allocation.

  14. Relationships between carbon fluxes and environmental factors in a drip-irrigated, film-mulched cotton field in arid region.

    Directory of Open Access Journals (Sweden)

    Xiaoyu Li

    Full Text Available Environmental factors and human activities play important roles in carbon fixation and emissions generated from croplands. Eddy covariance measurements in a drip-irrigated, film-mulched cotton field were used to analyze the relationships between carbon fluxes and environmental factors in Wulanwusu, northern Xinjiang, an arid region of Northwest China. Our results showed that the cumulative net carbon flux (NEE was -304.8 g C m-2 (a strong sink over the whole cotton growing season in 2012, which was more than that in cotton cropland without plastic film mulching and drip-irrigation. Moreover, when time is scaled up from a half-hour to a month, the correlations of gross primary production (GPP to air temperature (Tair, net solar radiation (Rn and soil water content (SWC gradually become stronger due to ecosystem resistance and resilience as well as the protection of plastic film mulching. The GPP is more strongly correlated with Rn than Tair at time scales from minutes to days, while it reverses at time scales from days to weeks. This outcome is largely determined by the biochemical characteristics of photosynthesis. SWC and vapor pressure deficit (VPD at all time scales are weakly correlated with GPP because plastic film mulching and regularly drip-irrigation allow soil to maintain sufficient water.

  15. Soil surface moisture estimation over a semi-arid region using ENVISAT ASAR radar data for soil evaporation evaluation

    Directory of Open Access Journals (Sweden)

    M. Zribi

    2011-01-01

    Full Text Available The present paper proposes a method for the evaluation of soil evaporation, using soil moisture estimations based on radar satellite measurements. We present firstly an approach for the estimation and monitoring of soil moisture in a semi-arid region in North Africa, using ENVISAT ASAR images, over two types of vegetation covers. The first mapping process is dedicated solely to the monitoring of moisture variability related to rainfall events, over areas in the "non-irrigated olive tree" class of land use. The developed approach is based on a simple linear relationship between soil moisture and the backscattered radar signal normalised at a reference incidence angle. The second process is proposed over wheat fields, using an analysis of moisture variability due to both rainfall and irrigation. A semi-empirical model, based on the water-cloud model for vegetation correction, is used to retrieve soil moisture from the radar signal. Moisture mapping is carried out over wheat fields, showing high variability between irrigated and non-irrigated wheat covers. This analysis is based on a large database, including both ENVISAT ASAR and simultaneously acquired ground-truth measurements (moisture, vegetation, roughness, during the 2008–2009 vegetation cycle. Finally, a semi-empirical approach is proposed in order to relate surface moisture to the difference between soil evaporation and the climate demand, as defined by the potential evaporation. Mapping of the soil evaporation is proposed.

  16. Quality of Life of Post-Mastectomy Women Living in a Semi-Arid Region of Brazil.

    Science.gov (United States)

    Araújo Neto, Emídio A; Alves, Beatriz C A; Gehrke, Flávia de S; Azzalis, Ligia A; Junqueira, Virginia C B; Sousa, Luiz Vinicius de A; Adami, Fernando; Fonseca, Fernando L A

    2017-06-05

    Health is the major reference regarding quality of life; when it comes to breast cancer in particular, the loss of a breast traumatically affects a woman's life, reflecting on her quality of life. Recognizing this problem, our aim was to investigate the quality of life of women who live in a semi-arid region of Brazil after breast cancer mastectomy. In this exploratory, transversal and observational study, a Brazilian variantof the shorter version of the original instrument from the World Health Organization Quality of Life (WHOQOL-BREF), applied in the study population, was analyzed and their socio-demographic profile was obtained. The sample was composed of 50 mastectomized women. The 50 included patients comprised women at a mean age of 54 years. Most of them had finished elementary school, and their average income was one Brazilian minimum monthly wage. Regarding the data related to quality of life, the highest score was found in the social relationships domain (4.29) followed by the psychological (4.09) and environmental (3.88) domains. The lowest score observed was for the physical domain (3.48). With these findings we can say that social and psychological parameters are driving factors of the quality of life in post-mastectomy women. Therefore, these results are useful to establish strategies to improve the quality of life of breast cancer mastectomy patients.

  17. Acarine infracommunities associated with the Mexican free-tailed bat, Tadarida brasiliensis mexicana (Chiroptera: Molossidae) in arid regions of Mexico.

    Science.gov (United States)

    Guzmán-Cornejo, C; García-Prieto, L; Morales-Malacara, J B; Pérez-Ponce De León, G

    2003-11-01

    The Mexican free-tailed bat, Tadarida brasiliensis mexicana, is one of the most widely distributed bats, and its range includes the whole Mexican territory. Ectoparasites of this bat have been the subject of isolated reports, but no studies of its community ecology have been conducted. The acarine infracommunities associated with this bat were analyzed, comparing bat populations from three arid regions of Mexico: an abandoned factory in Nombre de Dios, Durango; a cave in Santiago, Nuevo León; and a church in Concepción del Oro, Zacatecas. The acarine infracommunity in Nuevo Le6n's bats exhibited the highest levels of diversity as reflected by a higher richness, a lower dominance, and a moderate and relatively homogeneous abundance in this locality in relation to the other two. This pattern is influenced by stable cave conditions relative to artificial habitats. Notwithstanding, further studies are required to determine whether or not different habitat conditions are a primary factor in the process of structuring the acari infracommunities.

  18. Structural variations among monocot emergent and amphibious species from lakes of the semi-arid region of Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    KRB Leite

    Full Text Available Temporary lakes are common in the semi-arid region of the State of Bahia and form water mirrors in the rainy season. In this period, various vegetal species appear having different life forms adapted to the seasonality conditions of the rainfall regime. This work surveyed the adaptive anatomical structures of some emergent and amphibious monocot species occurring in these lakes. We studied the anatomy of roots, rhizomes, leaves and scapes of Cyperus odoratus, Oxycaryum cubense, Pycreus macrostachyos (Cyperaceae - amphibious species; and of Echinodorus grandiflorus (Alismataceae, Eichhornia paniculata (Pontederiaceae and Habenaria repens (Orchidaceae - emergent species. The anatomical features of the dermal, fundamental and vascular systems confirming the tendency of the adaptive convergence of these plants to temporary lacustrine the environment include: single layered epidermal cells with a thin cuticle layer in the aerial organs; the presence of air canals in all the organs; few or no supporting tissues; and less numerous conducting elements and thinner cell walls in the xylem. The reduction of the supporting tissues, the number of stomata, which can even be absent, and the number of conducting elements and the degree of cell wall lignification in the xylem of the emergent species is more accentuated than that of the amphibious species. The pattern of distribution of aerenchyma in the roots of the studied species was considered important to distinguish between amphibious and emergent life forms.

  19. Structural variations among monocot emergent and amphibious species from lakes of the semi-arid region of Bahia, Brazil.

    Science.gov (United States)

    Leite, K R B; França, F; Scatena, V I

    2012-02-01

    Temporary lakes are common in the semi-arid region of the State of Bahia and form water mirrors in the rainy season. In this period, various vegetal species appear having different life forms adapted to the seasonality conditions of the rainfall regime. This work surveyed the adaptive anatomical structures of some emergent and amphibious monocot species occurring in these lakes. We studied the anatomy of roots, rhizomes, leaves and scapes of Cyperus odoratus, Oxycaryum cubense, Pycreus macrostachyos (Cyperaceae) - amphibious species; and of Echinodorus grandiflorus (Alismataceae), Eichhornia paniculata (Pontederiaceae) and Habenaria repens (Orchidaceae) - emergent species. The anatomical features of the dermal, fundamental and vascular systems confirming the tendency of the adaptive convergence of these plants to temporary lacustrine the environment include: single layered epidermal cells with a thin cuticle layer in the aerial organs; the presence of air canals in all the organs; few or no supporting tissues; and less numerous conducting elements and thinner cell walls in the xylem. The reduction of the supporting tissues, the number of stomata, which can even be absent, and the number of conducting elements and the degree of cell wall lignification in the xylem of the emergent species is more accentuated than that of the amphibious species. The pattern of distribution of aerenchyma in the roots of the studied species was considered important to distinguish between amphibious and emergent life forms.

  20. Commercialization of animal-derived remedies as complementary medicine in the semi-arid region of Northeastern Brazil.

    Science.gov (United States)

    Alves, Rômulo R N; Léo Neto, Nivaldo A; Brooks, Sharon E; Albuquerque, Ulysses P

    2009-07-30

    In this study, we aim to document the use of animal species in traditional medicine and healing practices in the semi-arid region of Northeastern Brazil. While widespread and of great importance to large population that has limited access to contemporary medicine, such practices are poorly understood and the potential value of medicinal animal species largely unknown. Based on interviews with the merchants of medicinal animals, we calculated the informant consensus factor (ICF) to determine the consensus over which species are effective for particular ailments, as well as the species relative importance to determine the extent of potential utilization of each species. We describe the therapeutic effects of 36 animal species used medicinally. The zootherapeutical products sold commercially are used to treat 40 health problems that were classified into 10 broad categories. We also highlight those species valued for their effectiveness against a range of ailments. The highest ICF value (0.91) was cited for diseases of the skin and subcutaneous tissue, which include relief of symptoms such as acne and furuncles. This study demonstrates that many animal species play an important role in healing practices. Animals provide the raw materials for remedies prescribed clinically and are also used in the form of amulets and charms in magic-religious rituals and ceremonies. The medicinal value of animal species depends on the local knowledge that exists within user communities, and therefore, the conservation of animal species is imperative to the preservation of local medicinal knowledge and culture.

  1. Political participation and sustainability: reflections on a research-intervention with youngs in Cearas’s semi-arid region

    Directory of Open Access Journals (Sweden)

    Domingos Arthur Feitosa Petrola

    2018-02-01

    Full Text Available Participating socially and politically in the country's life still is a huge democratic challenge, especially when it concerns Brazilian youth. This research therefore sought to understand the social and political participation of young people in the semi-arid region, analyzing their relations with sustainability. With a qualitative nature, it was developed between May and August of 2014 with a group of subjects, with 15 to 30 years old, members of a non-governmental organization in the city of Arneiroz, countryside of the State of Ceara. The type of research is expressed in the research-intervention which assumes a political and methodological feature. The Freirean Culture Circles were also used as a "place-instruments" of data collection. By the results, it was observed that young people have demonstrated that, despite recognizing the importance of acting and assuming a political role at the transformation of reality through participation mechanisms, they do not feel invited to occupy this place given the traditional and technocratic model of social control and, therefore, they show little interest in effective participatory action. It is urgent to elaborate methodologies that promote and reach to a committed and critical participation, structured through an ideal of sustainable and ethical public policies, stimulating more creative forms of emancipation.

  2. Development and water requirements of cowpea under climate change conditions in the Brazilian semi-arid region

    Directory of Open Access Journals (Sweden)

    Edmilson G. Cavalcante Junior

    Full Text Available ABSTRACT This study aimed to determine the impacts that climate change may cause on the development and evapotranspiration of cowpea, in semi-arid climate region of Northeast Brazil. The study was conducted in the municipalities of Apodi, Ipanguaçu and Mossoró, in the state of Rio Grande do Norte. In order to evaluate the influence of climate change on crop water consumption, changes in air temperature and relative humidity were simulated using the PRECIS climate model. Two scenarios of emissions were evaluated based on the report of the Intergovernmental Panel on Climate Change: a pessimistic named A2 and an optimistic B2. The duration of the crop cycle showed an average reduction of 14 and 23 days for the optimistic and pessimistic scenarios, respectively. Temperatures will be well above the limit tolerated by crop, which could have a negative impact on its development and yield. There will be a decrease in total evapotranspiration of 4.8%, considering the optimistic scenario, and 8.7% in the pessimistic scenario.

  3. A comparison between index of entropy and catastrophe theory methods for mapping groundwater potential in an arid region.

    Science.gov (United States)

    Al-Abadi, Alaa M; Shahid, Shamsuddin

    2015-09-01

    In this study, index of entropy and catastrophe theory methods were used for demarcating groundwater potential in an arid region using weighted linear combination techniques in geographical information system (GIS) environment. A case study from Badra area in the eastern part of central of Iraq was analyzed and discussed. Six factors believed to have influence on groundwater occurrence namely elevation, slope, aquifer transmissivity and storativity, soil, and distance to fault were prepared as raster thematic layers to facility integration into GIS environment. The factors were chosen based on the availability of data and local conditions of the study area. Both techniques were used for computing weights and assigning ranks vital for applying weighted linear combination approach. The results of application of both modes indicated that the most influential groundwater occurrence factors were slope and elevation. The other factors have relatively smaller values of weights implying that these factors have a minor role in groundwater occurrence conditions. The groundwater potential index (GPI) values for both models were classified using natural break classification scheme into five categories: very low, low, moderate, high, and very high. For validation of generated GPI, the relative operating characteristic (ROC) curves were used. According to the obtained area under the curve, the catastrophe model with 78 % prediction accuracy was found to perform better than entropy model with 77 % prediction accuracy. The overall results indicated that both models have good capability for predicting groundwater potential zones.

  4. Seasonal Evaporation and Surface Energy Budget Estimation Across an Arid Agricultural Region in Saudi Arabia: Quantifying Groundwater Extraction

    Science.gov (United States)

    Aragon, B.; Huang, D.; Houborg, R.; Dasari, H. P.; Hoteit, I.; McCabe, M.

    2017-12-01

    In arid-land agricultural environments, knowledge of the water and energy budget is critical in order to sustainably manage the allocation and use of water resources. Using long-term weather reanalysis data from the Weather Research and Forecasting (WRF) model and a time-series record of Landsat 8 imagery, we apply the Priestly-Taylor Jet Propulsion Lab (PT-JPL) model to estimate the energy budget over the Al Jawf agricultural region in the north of Saudi Arabia. This zone generates a significant proportion of the agricultural production in Saudi Arabia and consumes an important fraction of the non-renewable water resources. This research contributes towards efforts seeking to quantify the precise amount of water that is used in agriculture - a difficult variable given that the overwhelming majority of supply comes from groundwater extraction. Results of this research can be used to improve crop management and to mitigate aquifer over-exploitation by monitoring the indiscriminate use of water and establishing bounds around the rates of groundwater withdrawal.

  5. Random Forest Classification of Wetland Landcovers from Multi-Sensor Data in the Arid Region of Xinjiang, China

    Directory of Open Access Journals (Sweden)

    Shaohong Tian

    2016-11-01

    Full Text Available The wetland classification from remotely sensed data is usually difficult due to the extensive seasonal vegetation dynamics and hydrological fluctuation. This study presents a random forest classification approach for the retrieval of the wetland landcover in the arid regions by fusing the Pléiade-1B data with multi-date Landsat-8 data. The segmentation of the Pléiade-1B multispectral image data was performed based on an object-oriented approach, and the geometric and spectral features were extracted for the segmented image objects. The normalized difference vegetation index (NDVI series data were also calculated from the multi-date Landsat-8 data, reflecting vegetation phenological changes in its growth cycle. The feature set extracted from the two sensors data was optimized and employed to create the random forest model for the classification of the wetland landcovers in the Ertix River in northern Xinjiang, China. Comparison with other classification methods such as support vector machine and artificial neural network classifiers indicates that the random forest classifier can achieve accurate classification with an overall accuracy of 93% and the Kappa coefficient of 0.92. The classification accuracy of the farming lands and water bodies that have distinct boundaries with the surrounding land covers was improved 5%–10% by making use of the property of geometric shapes. To remove the difficulty in the classification that was caused by the similar spectral features of the vegetation covers, the phenological difference and the textural information of co-occurrence gray matrix were incorporated into the classification, and the main wetland vegetation covers in the study area were derived from the two sensors data. The inclusion of phenological information in the classification enables the classification errors being reduced down, and the overall accuracy was improved approximately 10%. The results show that the proposed random forest

  6. Calibration of a Distributed Hydrological Model using Remote Sensing Evapotranspiration data in the Semi-Arid Punjab Region of Pakista

    Science.gov (United States)

    Becker, R.; Usman, M.

    2017-12-01

    A SWAT (Soil Water Assessment Tool) model is applied in the semi-arid Punjab region in Pakistan. The physically based hydrological model is set up to simulate hydrological processes and water resources demands under future land use, climate change and irrigation management scenarios. In order to successfully run the model, detailed focus is laid on the calibration procedure of the model. The study deals with the following calibration issues:i. lack of reliable calibration/validation data, ii. difficulty to accurately model a highly managed system with a physically based hydrological model and iii. use of alternative and spatially distributed data sets for model calibration. In our study area field observations are rare and the entirely human controlled irrigation system renders central calibration parameters (e.g. runoff/curve number) unsuitable, as it can't be assumed that they represent the natural behavior of the hydrological system. From evapotranspiration (ET) however principal hydrological processes can still be inferred. Usman et al. (2015) derived satellite based monthly ET data for our study area based on SEBAL (Surface Energy Balance Algorithm) and created a reliable ET data set which we use in this study to calibrate our SWAT model. The initial SWAT model performance is evaluated with respect to the SEBAL results using correlation coefficients, RMSE, Nash-Sutcliffe efficiencies and mean differences. Particular focus is laid on the spatial patters, investigating the potential of a spatially differentiated parameterization instead of just using spatially uniform calibration data. A sensitivity analysis reveals the most sensitive parameters with respect to changes in ET, which are then selected for the calibration process.Using the SEBAL-ET product we calibrate the SWAT model for the time period 2005-2006 using a dynamically dimensioned global search algorithm to minimize RMSE. The model improvement after the calibration procedure is finally evaluated based

  7. LEGUMINOUS COVER CROPS FOR BANANA PLANTATIONS IN SEMI-ARID REGIONS

    Directory of Open Access Journals (Sweden)

    MATEUS AUGUSTO LIMA QUARESMA

    2017-01-01

    Full Text Available High temperatures and low rainfall characterize the Brazilian semiarid regions. This regional climate demands the adoption of practices that increase the efficiency and sustainability of local farming. This study aimed to assess the ability of two perennial herbaceous leguminous species, calopo and tropical kudzu, to provide permanent soil cover in banana plantations in Jequitinhonha Valley, northeast Minas Gerais state, Brazil. To this end, we evaluated the differences of calopo and tropical kudzu in soil cover capacity and the amount of senescent phytomass deposited on the soil surface, nutrient content in senescent phytomass, as well as their effects on temperature and soil moisture, compared with bare soil in two experimental sites. The results showed that, compared with tropical kudzu, calopo had a higher soil cover capacity and was more effective at increasing organic material and nutrients in the soil owing to the relatively higher amount of senescent phytomass deposited on the soil surface. However, both calopo and tropical kudzu reduced soil temperature and increase soil moisture compared with bare soil. Overall, we concluded that these species can deposit high levels of senescence in the soil, providing several benefits to the cultivation system of banana plants in the semiarid regions.

  8. Spatiotemporal distribution of airborne particulate metals and metalloids in a populated arid region

    Science.gov (United States)

    Prabhakar, Gouri; Sorooshian, Armin; Toffol, Emily; Arellano, Avelino F.; Betterton, Eric A.

    2014-08-01

    A statistical analysis of data from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network of aerosol samplers has been used to study the spatial and temporal concentration trends in airborne particulate metals and metalloids for southern Arizona. The study region is a rapidly growing area in southwestern North America characterized by high fine soil concentrations (among the highest in the United States), anthropogenic emissions from an area within the fastest growing region in the United States, and a high density of active and abandoned mining sites. Crustal tracers in the region are most abundant in the summer (April-June) followed by fall (October-November) as a result of dry meteorological conditions which favor dust emissions from natural and anthropogenic activity. A distinct day-of-week cycle is evident for crustal tracer mass concentrations, with the greatest amplitude evident in urban areas. There have been significant reductions since 1988 in the concentrations of toxic species that are typically associated with smelting and mining. Periods with high fine soil concentrations coincide with higher concentrations of metals and metalloids in the atmosphere, with the enhancement being higher at urban sites.

  9. Modelling the topsoil carbon stock of agricultural lands with the Stochastic Gradient Treeboost in a semi-arid Mediterranean region

    KAUST Repository

    Schillaci, Calogero

    2016-10-29

    ETM+ panchromatic Band 8 were the most important predictors of SOC stock. Finally, SOC stocks were estimated for each land cover class. SGT predicted SOC stock better than GSOC and ISRIC for most data. This resulted in a percentage of data in the prediction confidence interval ± 50% compared to the observed values of 71.4%, 65.8%, and 50.7% for SGT, GSOC, and SGT, respectively. This consisted of a higher R2 and a slope (β) that was closer to 1 for the pseudo-regression constructed with SGT compared to GSOC and ISRIC. In conclusion, the results of the present study showed that the integration of RS with climatic and soil texture spatial data could strongly improve SOC prediction in a semi-arid Mediterranean region. In addition, the panchromatic band of Landsat 7 ETM + was more predictive compared to the conventionally used NDVI. This information is crucial to guiding decision-making processes, especially at a regional scale and/or in semi-arid Mediterranean areas. The model performance of the SGT could be further improved by adopting predictors with greater spatial resolutions. The results of the present experiment yield valuable information, especially for assessing climate change or land use change scenarios for SOC stocks and their spatial distribution.

  10. Modelling the topsoil carbon stock of agricultural lands with the Stochastic Gradient Treeboost in a semi-arid Mediterranean region

    KAUST Repository

    Schillaci, Calogero; Lombardo, Luigi; Saia, Sergio; Fantappiè , Maria; Mä rker, Michael; Acutis, Marco

    2016-01-01

    ETM+ panchromatic Band 8 were the most important predictors of SOC stock. Finally, SOC stocks were estimated for each land cover class. SGT predicted SOC stock better than GSOC and ISRIC for most data. This resulted in a percentage of data in the prediction confidence interval ± 50% compared to the observed values of 71.4%, 65.8%, and 50.7% for SGT, GSOC, and SGT, respectively. This consisted of a higher R2 and a slope (β) that was closer to 1 for the pseudo-regression constructed with SGT compared to GSOC and ISRIC. In conclusion, the results of the present study showed that the integration of RS with climatic and soil texture spatial data could strongly improve SOC prediction in a semi-arid Mediterranean region. In addition, the panchromatic band of Landsat 7 ETM + was more predictive compared to the conventionally used NDVI. This information is crucial to guiding decision-making processes, especially at a regional scale and/or in semi-arid Mediterranean areas. The model performance of the SGT could be further improved by adopting predictors with greater spatial resolutions. The results of the present experiment yield valuable information, especially for assessing climate change or land use change scenarios for SOC stocks and their spatial distribution.

  11. Measurement on the Harmony Coefficient of Agro-eco-economic System in the Arid Region

    Institute of Scientific and Technical Information of China (English)

    Qijun; LIU; Zhaonan; LI

    2016-01-01

    On the basis of the present research progress of ecological agriculture,we take Minle County and Linze County located in the middle reaches of Heihe River as the typical research units.Based on the rural social and economic data during the period of 2000-2010,theory and method of mathematical statistics are used to establish the measure theory and model of agro-eco-economic system harmony coefficient,including efficacy function,function of harmony coefficient,harmony coefficient and level of harmony coefficient.Based on the actual situation of research region,evaluation indicator system of agro-eco-economic system is established and measurement is carried out.Results show that the regional agro-eco-economic system in research region was in a serious imbalance in 2000-2013.The harmony coefficient of Minle showed a slight rise from 2000 to 2004,and then presented a fluctuating decline.Its rank of harmony coefficient experienced serious imbalance-extreme imbalance-moderate imbalance-low imbalance-serious imbalance-high imbalance.At the same time,the similar tendency happened in Linze County.The measuring results of subsystem in 2000-2013 further indicated that except that the harmony coefficient of economic subsystem in Minle County and Linze County was moderate and high,the ecological subsystem was at Level II and Level III,and social subsystem was at Level IV and Level III,in high and low imbalance status.Finally,several recommendations were put forward for optimizing agro-eco-economic system.

  12. Optimal use of agrometeorological information for sustainable agricultural production in semi-arid regions of India

    International Nuclear Information System (INIS)

    Surender, S.; Diwan, S.; Rao, V.U.M.

    2006-05-01

    The concept of sustainable agriculture encompasses ecological, economic and social problems in which weather and climate can be of great importance. Despite considerable technological advancement and improved irrigation facilities, Indian farmers are still dependent on seasonal rains, which are highly variable both in time and space. Inclement weather events like droughts, floods, cold and heat waves, hails, squalls, tropical storms severely affect the agricultural production. Their harmful effects may be partially reduced if the occurrence of these events is predicted in advance and farmers are suitably advised to take preventive/corrective measures. With the objective to help the farmers maximize profits by decreasing weather related losses, increasing the timeliness of farm operations and to reduce environmental pollution through the optimal use of agricultural chemicals, the location specific/regional Agrometeorological Advisory Service was initiated in the year 1991. The forecasting skills of most of the weather parameters at Hisar have improved considerably over the years. Now, it is time to integrate and make use of vast agrometeorological information available online in preparing weather based advisories for in-season agricultural operations both for single locations and on a meso or regional scale as desired. This can be further strengthened through input from new technologies such as neural network, remote sensing, GIS, ground measurements and modeling applications along with traditional wisdom available with the farming communities should be integrated to further strengthen the location specific weather forecasting system for the development of sustainable and more efficient crop production systems. (author)

  13. Combining Estimation of Green Vegetation Fraction in an Arid Region from Landsat 7 ETM+ Data

    Directory of Open Access Journals (Sweden)

    Kun Jia

    2017-11-01

    Full Text Available Fractional vegetation cover (FVC, or green vegetation fraction, is an important parameter for characterizing conditions of the land surface vegetation, and also a key variable of models for simulating cycles of water, carbon and energy on the land surface. There are several types of FVC estimation models using remote sensing data, and evaluating their performance over a specific region is of great significance. Therefore, this study firstly evaluated three types of FVC estimation models using Landsat 7 ETM+ data in an agriculture region of Heihe River Basin, China, and then proposed a combination strategy from different individual models to improve the FVC estimation accuracy, which employed the multiple linear regression (MLR and Bayesian model average (BMA methods. The validation results indicated that the spectral mixture analysis model with three endmembers (SMA3 achieved the best FVC estimation accuracy (determination coefficient (R2 = 0.902, root mean square error (RMSE = 0.076 among the seven individual models using Landsat 7 ETM+ data. In addition, the MLR and BMA combination methods could both improve FVC estimation accuracy (R2 = 0.913, RMSE = 0.063 and R2 = 0.904, RMSE = 0.069 for MLR and BMA, respectively. Therefore, it could be concluded that both MLR and BMA combination methods integrating FVC estimates from different models using Landsat 7 ETM+ data could effectively weaken the estimation errors of individual models and improve the final FVC estimation accuracy.

  14. The Impact of Urbanization on the Regional Aeolian Dynamics of an Arid Coastal Dunefield

    Science.gov (United States)

    Smith, Alexander; Jackson, Derek; Cooper, Andrew

    2016-04-01

    The anthropogenic impact on the geomorphology of many landscapes are inextricably connected but are often neglected due to the difficulty in making a direct link between the quasi natural and human processes that impact the environment. This research focuses on the Maspalomas dunefield, located on the southern coast of Gran Canaria, in the Canary Island Archipelago. The tourism industry in Maspalomas has led to intensive urbanization since the early 1960's over an elevated alluvial terrace that extends into the dunefield. Urbanization has had a substantial impact on both the regional airflow conditions and the geomorphological development of this transverse dune system. As a result airflow and sediment has been redirected in response to the large scale construction efforts. In situ data was collected during field campaigns using high resolution three-dimensional anemometry to identify the various modifications within the dunefield relative to incipient regional airflow conditions. The goal is to analyse the flow conditions near the urbanized terrace in relation to areas that are located away from the influence of the buildings and to verify numerical modelling results. Computational Fluid Dynamics (CFD) modelling is used in order to expand the areal extent of analysis by providing an understanding of relevant flow dynamics (e.g. flow velocity, directionality, turbulence, shear stresses, etc.) at the mesoscale. An integrative three dimensional model for CFD simulations was created to address the impact of both the urban area (i.e. hotels, commercial centers, and residential communities) as well as the dune terrain on regional flow conditions. Early modelling results show that there is significant flow modification around the urban terrace with streamline compression, acceleration, and deflection of flow on the windward side of the development. Consequently downwind of the terrace there is an area of highly turbulent flow conditions and well developed separation and

  15. Field-based experimental water footprint study of sunflower growth in a semi-arid region of China.

    Science.gov (United States)

    Qin, Lijie; Jin, Yinghua; Duan, Peili; He, Hongshi

    2016-07-01

    Field-scale changes in the water footprint during crop growth play an important role in formulating sustainable water utilisation strategies. This study aimed to explore field-scale variation in the water footprint of growing sunflowers in the western Jilin Province, China, during a 3-year field experiment. The goals of this study were to (1) determine the components of the 'blue' and 'green' water footprints for sunflowers sown with water, and (2) analyse variations in water footprints and soil water balance under different combinations of temperature and precipitation. Specific actions could be adopted to maintain sustainable agricultural water utilisation in the semi-arid region based on this study. The green, blue, and grey water footprints accounted for 93.7-94.7%, 0.4-0.5%, and 4.9-5.8%, respectively, of the water footprint of growing sunflowers. The green water footprint for effective precipitation during the growing season accounted for 58.8% in a normal drought year but 48.2% in an extreme drought year. When the effective precipitation during the growing season could not meet the green water use, a moisture deficit arose. This increase in the moisture deficit can have a significant impact on soil water balance. Green water was the primary water source for sunflower growth in the study area, where a scarcity of irrigation water during sunflower growth damaged the soil water balance, particularly in years with continuous drought. The combination of temperature and precipitation effected the growing environment, leading to differences in yield and water footprint. The field experiments in this area may benefit from further water footprint studies at the global, national and regional scale. © 2016 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. © 2016 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of

  16. Impacts of Climate Change and Anthropogenic Activities on the Ecological Restoration of Wetlands in the Arid Regions of China

    Directory of Open Access Journals (Sweden)

    Haibo Wang

    2016-03-01

    Full Text Available As an important part of the global ecosystem, wetlands and their dynamics greatly influence regional eco-environment systems. To understand the distributions, change processes and temporal-spatial characteristics of the wetlands of the inland river basin in an arid region (Heihe River Basin, HRB, this paper employed multi-source remote sensing data to facilitate multi-temporal monitoring of the HRB wetland using a wetland information extraction method. First, we performed monitoring of these wetlands for the years 2000, 2007, 2011 and 2014; then, we analyzed the variation characteristics of the spatial-temporal dynamics of the wetlands in the HRB over the last 15 years via the landscape dynamic change model and the transformation matrix. In addition, we studied the possible driving mechanisms of these changes. The research results showed that the total area of the HRB wetlands had decreased by 2959.13 hectares in the last 15 years (Since 2000, and the annual average loss was −1.09%. The dynamics characterizing the HRB wetlands generally presented a trend of slow increase after an initial decrease, which can be classified into three stages. From 2000 to 2007, the total wetland area rapidly decreased; from 2007 to 2011, the area slowly decreased; and from 2011 to 2014, the area gradually increased. The dynamic changing processes characterizing the wetland resources were ascribed to a combination of natural processes and human activities. The main driving mechanisms of wetland dynamic changes include climatic conditions, upper reach water inflows, population, water resources, cultivated area, and policy. The findings of this study can served as reference and support for the conservation and management of wetland resources in the HRB.

  17. Rainwater harvesting in arid and semi-arid zones

    NARCIS (Netherlands)

    Boers, T.M.

    1994-01-01

    In arid and semi-arid regions, the scarcity of water can be alleviated by rainwater harvesting, which is defined as a method of inducing, collecting, storing, and conserving local surface runoff for agriculture. Rainwater harvesting can be applied with different

  18. Impact of anthropogenic climate change and human activities on environment and ecosystem services in arid regions.

    Science.gov (United States)

    Mahmoud, Shereif H; Gan, Thian Y

    2018-08-15

    The implications of anthropogenic climate change, human activities and land use change (LUC) on the environment and ecosystem services in the coastal regions of Saudi Arabia were analyzed. Earth observations data was used to drive land use categories between 1970 and 2014. Next, a Markov-CA model was developed to characterize the dynamic of LUC between 2014 and 2100 and their impacts on regions' climate and environment. Non-parametric change point and trend detection algorithms were applied to temperature, precipitation and greenhouse gases data to investigate the presence of anthropogenic climate change. Lastly, climate models were used to project future climate change between 2014 and 2100. The analysis of LUC revealed that between 1970 and 2014, built up areas experienced the greatest growth during the study period, leading to a significant monotonic trend. Urban areas increased by 2349.61km 2 between 1970 and 2014, an average increase of >53.4km 2 /yr. The projected LUC between 2014 and 2100 indicate a continued increase in urban areas and irrigated cropland. Human alteration of land use from natural vegetation and forests to other uses after 1970, resulted in a loss, degradation, and fragmentation, all of which usually have devastating effects on the biodiversity of the region. Resulting in a statistically significant change point in temperature anomaly after 1968 with a warming trend of 0.24°C/decade and a downward trend in precipitation anomaly of 12.2mm/decade. Total greenhouse gas emissions including all anthropogenic sources showed a statistically significant positive trend of 78,090Kt/decade after 1991. This is reflected in the future projection of temperature anomaly between 1900 and 2100 with a future warming trend of 0.19°C/decade. In conclusion, human activities, industrial revelation, deforestation, land use transformation and increase in greenhouse gases had significant implications on the environment and ecosystem services of the study area

  19. Subsurface phosphorus transport through a no-till field in the semi arid Palouse region

    Science.gov (United States)

    Norby, J. C.; Brooks, E. S.; Strawn, D. G.

    2017-12-01

    Excess application of fertilizers containing nitrogen and phosphorus for farming use has led to ongoing water quality issues in the United States. When these nutrients leave agronomic systems, and enter water bodies in large quantities, algal bloom and eutrophication can occur. Extensive studies focusing on phosphorus as a pollutant from agronomic systems have been conducted in the many regions of the United States; however, there has been a lack of studies completed in the semiarid Palouse region of eastern Washington and western Idaho. The goal of this research study was to better understand how no-till farm management has altered soil P temporally and the current availability for off-site transport of P throughout an artificially drained catchment at the Cook Agronomy Farm in Pullman, WA. We also attempted to determine the processes responsible for subsurface flow of phosphorus, specifically through preferential flow pathways. Dissolved reactive P (DRP)concentrations of subsurface drainage from a artificial drain exceeded TMDL threshold concentrations during numerous seasonal high flow events over the two-year study time frame. Soil analyses show a highly variable distribution of water-extractable P across the sub-catchment area and initial results suggest a translocation of P species deeper into the soil profile after implementing no-till practices in 1998. We hypothesized that a greater network of macropores from lack of soil disturbance allow for preferential flow of nutrient-laden water deeper into the subsurface and to the artificial drain system. Simulated flow experiments on soil cores from the study site showed large-scale macropore development, extreme variability in soil conductivity, and high P adsorption potential for the soils, suggesting a disconnect between P movement through macropore soil and subsurface drainage water rich in DRP at the artificial drain line outlet.

  20. The Impact of Green Water Management Strategies on Household-Level Agricultural Water Productivity in a Semi-Arid Region: A Survey-based Assessment

    Directory of Open Access Journals (Sweden)

    Afton Clarke-Sather

    2017-12-01

    Full Text Available This study evaluates the effect of policies that encourage farmers to shift to crops with higher water productivity (CWP on the farm-level CWP of agricultural systems in a semi-arid region of western China. We combine survey results of farmers’ historical cropping decisions from a 2010 survey with estimates of CWP from agronomic experiments analogous to actual cultivation practices in the region to model CWP at the farm level and understand changes driven by shifting crops. Policies designed to replace subsistence agricultural systems with two cash crops; potatoes and maize; resulted in an increase in the CWP of semi-arid agricultural systems of approximately 30% between the years 1990–2010. This change was driven by shifting to crops that have a peak water demand that occurs in the portions of the growing season with the highest rainfall. The results of this article illustrate the potential of shifts in cropping patterns to increase the CWP of agricultural systems in semi-arid regions.

  1. Quantification of the impacts of climate change and human agricultural activities on oasis water requirements in an arid region: a case study of the Heihe River basin, China

    Science.gov (United States)

    Liu, Xingran; Shen, Yanjun

    2018-03-01

    Ecological deterioration in arid regions caused by agricultural development has become a global issue. Understanding water requirements of the oasis ecosystems and the influences of human agricultural activities and climate change is important for the sustainable development of oasis ecosystems and water resource management in arid regions. In this study, water requirements of the main oasis in Heihe River basin during 1986-2013 were analyzed and the amount showed a sharp increase from 10.8 × 108 m3 in 1986 to 19.0 × 108 m3 in 2013. Both human agricultural activities and climate change could lead to the increase in water requirement. To quantify the contributions of agricultural activities and climate change to the increase in water requirements, partial derivative and slope method were used. Results showed that climate change and human agricultural activities, such as oasis expansion and changes in land cropping structure, has contributed to the increase in water requirement at rates of 6.9, 58.1, and 25.3 %, respectively. Overall, human agricultural activities were the dominant forces driving the increase in water requirement. In addition, the contribution of oasis expanding to the increased water requirement was significantly greater than that of other concerned variables. This reveals that controlling the oasis scale is extremely important and effective for balancing water for agriculture and ecosystems and to achieving a sustainable oasis development in arid regions.

  2. Flowering phenology in the arid winter rainfall region of southern Africa

    Directory of Open Access Journals (Sweden)

    M. Struck

    1994-10-01

    Full Text Available The impact of physical factors on the flowering phenology of a succulent karroid community in the winter rainfall region of the northwestern Cape, South Africa, based upon a three year study on permanent plots, is examined, (in the permanent plots, flowering of the shrubby species extended over a period of 4 to 4'/i> months each year, while blooming ot the therophytes peaked m the first half of the flowering season. Species composition and numbers of individuals in the therophytes and geophytes offering flowers varied greatly according to the pattern and amount of seasonal precipitation. Despite these variations a consistent flowering sequence between the years was observed. Possible relations between the flowering phenology and the climatic variables are discussed in detail. The present data suggest that the onset of flowering is determined indirectly by the first drop in temperature in autumn, indicating the beginning of the rainy season and presumably the start of the growing period, and/or by the increase of temperatures in the beginning of spring. The pattern and amount of rainfall within a given season mainly influenced the duration of anthesis and the number of flowers produced.

  3. Ecological restoration and effect investigation of a river wetland in a semi-arid region, China

    Science.gov (United States)

    Xu, S.; Jiang, X.; Liu, Y.; Fu, Y.; Zhao, Q.

    2015-05-01

    River wetlands are heavily impacted by human intervention. The degradation and loss of river wetlands has made the restoration of river ecosystems a top priority. How to rehabilitate rivers and their services has been a research focus. The main goal of it is to restore the river wetland ecosystems with ecological methods. The Gudong River was selected as a study site in Chaoyang city in this study. Based on the analysis of interference factors in the river wetland degradation, a set of restoration techniques were proposed and designed for regional water level control, including submerged dikes, ecological embankments, revegetation and dredging. The restoration engineering has produced good results in water quality, eco-environment, and landscape. Monthly reports of the Daling River show that the water quality of Gudong River was better than Grade III in April 2013 compared with Grade V in May 2012. The economic benefit after restoration construction is 1.71 million RMB per year, about 1.89 times that before. The ratio of economic value, social value and eco-environmental value is 1:4:23.

  4. Strategies for Developing Drought Tolerant Cowpea varieties for the Semi-Arid regions of Nigeria

    International Nuclear Information System (INIS)

    Ishiyaku, M. F.

    2000-10-01

    Drought, meaning the deviation of the total amount and or distribution of precipitation from the normal is an important factor that cause untold human suffering as well as social and economic loss for any nation. Its effects are often felt by places so remote from the area of occurrence. In the agricultural sector, where its effect are most felt, drought risk greatly reduce investment in agriculture. This will no doubt contribute to national food insecurity and social unrest. Of the measures often prescribed to combat the menace of drought include the development and planting of drought resistant/tolerant crop varieties. This paper discusses the strategies for developing drought tolerant cowpea varieties for the drought-prone regions of Nigeria. These strategies include the introduction and screening of candidate drought tolerant cowpea germplasm and their utilization in developing new improved genotypes. The screening of populations will be carried out by adopting novel screening techniques in the lab as well as in the field. In addition to utilizing existing genetic variation to develop varieties with tolerance to drought, new sources of variation will be created artificially for the various traits known to confer tolerance to drought in cowpea. In creating genetic variability for drought tolerance traits artificially, the potential of irradiation induced mutation will be exploited

  5. Thermal Study on Extensive Green Roof Integrated Irrigation in Northwestern Arid Regions of China

    Directory of Open Access Journals (Sweden)

    Yajun Wang

    2017-11-01

    Full Text Available Selection of xerophils and drought tolerant plants is highly crucial in green roof techniques in the drought prone regions of Northwest China. In this study, the thermal performance under the natural conventional climate in summer was analyzed using a self-made simulation experimental platform through comparison of the internal surface temperature with and without green roofs. The distribution frequency of internal surface temperature was investigated by dividing internal surface temperature into several ranges. Statistical analysis showed that the frequency of internal surface temperature lower than 33 °C for green roofs was 91.8%, about 1.09 times higher than that for non-green roofs, and that the sum of internal surface temperature exceeding 35 °C was about one third of that for non-green roofs. The results proved that green roofs have a significant insulation effect. Moreover, the thermal insulation property of green roofs had a strong positive relation with outside temperature. The thermal insulation characteristic was improved as the outdoor temperature increased, additionally, it had a better insulation effect within two hours after irrigation.

  6. Data on fluoride concentration levels in semi-arid region of Medak, Telangana, South India

    Directory of Open Access Journals (Sweden)

    Adimalla Narsimha

    2018-02-01

    Full Text Available According to the World Health Organization recommendation, the optimal fluoride concentration levels in drinking water have to be in the range of 0.5 and 1.5 mg/L since this permissible range is essential for normal mineralization of bones and teeth as well as for dental enamel formation in human's body Bell and budwig, 1970; Adimalla and Venkatayogi, 2017; Narsimha and Sudarshan, 2013, 2016; 2017 [1,2,4,5,6]. If continues intake of high fluoride (>1.5 water can severely cause dental and skeletal fluorosis. The investigated area people majorly depend on groundwater for drinking purposes and fluoride concentration ranged from 0.2 to 7.4 mg/L with mean concentration of 2.7 mg/L and data was compared with WHO guidelines for drinking purposes. Overall, data reveals that the 57% of groundwater samples data was not safe for drinking purposes. Therefore, distribution of fluoride in the groundwater of Medak region in Telangana was suggested to intake drinking water, which are below level of fluoride concentration in the groundwater and take care about health implications.

  7. Environmental isotope studies in the arid regions of Western Rajasthan, India

    International Nuclear Information System (INIS)

    Nair, A.R.; Navada, S.V.; Kulkarni, K.M.; Kulkarni, U.P.; Joseph, T.B.

    2001-01-01

    An environmental isotope study carried out along an 'identified' buried river course in Jaisalmer showed that its expected head water connection with present day Himalayan sources to be very remote. The groundwater along the course is old as indicated by absence of tritium and low carbon-14 values. In an effort to understand the contribution of canal waters and return flow of irrigation waters to the groundwater and related problems in the command area of a large irrigation project, the area affected by canal water could be delineated. The ground water salinity is attributed both to the uplift of local saline groundwaters caused by water logging in the area as well as to evaporation from shallow groundwaters. Deep fresh groundwater is available in many parts in the desert region, which have been identified as palaeowaters: over exploitation of these old waters in some areas is indicated by their mixing with shallow groundwaters. Modem recharge is possible in the southern part of the state where comparatively higher precipitation is received. (author)

  8. Ethnopharmacological study of Stryphnodendron rotundifoliumin two communities in the semi-arid region of northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Dayanne Rakelly de Oliveira

    Full Text Available This work describes the local knowledge of the medicinal use of Stryphnodendron rotundifolium Mart., Fabaceae, according to informants in two areas of the Araripe bioregion, in the Northeast Region of Brazil. We used interviews to investigate the ethnomedicinal use of the local species to determine the mode of use, frequency of administration, duration of treatment and restrictions of use. In traditional medicine, the use of S. rotundifoliumis associated with the treatment of inflammatory and infectious diseases. The part of the plant most used was the stem bark (86.11%, the predominant mode of preparation was immersion in water (52.83%, and oral administration was the most cited (48.43%. For inflammatory and infectious diseases, the treatment lasted 3-10 days and the frequency of administration was 2-3 times/day. For gastroprotective effects, treatment lasted up to 30 days, and the herb was administered 1-3 times/day. For pain complaints, the therapy varied from 2-3 days to continuous administration.The informants (46.87% did not mention restrictions of use, except for pregnant women, with a rate of 25%. A comparison of these results with the ethnopharmacological information from other studies showed that some of the traditional indications are scientifically supported by the literature or clinical studies. Nevertheless, the results showed that pharmacologists have not fully investigated all the possible bioactivities that healers credit to this plant.

  9. Rainwater Management Model Development for Agriculture in the Savu Island Semi-Arid Region

    Directory of Open Access Journals (Sweden)

    Susilawati C.L.

    2012-01-01

    Full Text Available Savu Island is a semiarid region with few rainfalls. The meager annual rainfall of about 1,000-1,500 mm that lasts for three to five months tends to cause draught. To cope with this situation, the Author tries to develop a rainwater management model located in Daieko village. This model constitutes an infrastructure that consists of check dam series which are constructed by simulating a computerized model of decision supporting system called “Rainwater Management for Agriculture Decision Support System (RMA-DSS model” in the research location of Daieko village. Employing a simulated RMA-DSS model; the locations for check-dam series, and dug-wells can be determined, the size of potential irrigable lands can be determined based on water balance analysis of water samples taken from simulated check dams and inundated lands. Through this model the sufficiency of water supply for agricultural purposes and the land size for cultivation area can be predicted with a high degree of certainty.

  10. Report on the lands of the arid region of the United States with a more detailed account of the land of Utah with maps

    Science.gov (United States)

    Powell, John Wesley

    1879-01-01

    A report from Maj. J. W.Powell, geologist in charge of the United States Geographical and Geological Survey of the Rocky Mountain Region, upon the lands of the Arid Region of the United States, setting forth the extent of said region, and making suggestions as to the conditions under which the lands embraced within its limit may be rendered available for agricultural and grazing purposes. With the report is transmitted a statement of the rainfall of the western portion of the United States, with reports upon the subject of irrigation by Capt. C. E. Button, U. S. A., Prof. A. H. Thompson, and Mr. G. K. Gilbert.

  11. Significance of water fluxes in a deep arid-region vadose zone to waste disposal strategies

    International Nuclear Information System (INIS)

    Johnejack, K.R.; Blout, D.O.; Sully, M.J.; Emer, D.F.; Hammermeister, D.P.; Dever, L.G.; O'Neill, L.J.; Tyler, S.W.; Chapman, J.

    1994-01-01

    Recently collected subsurface site characterization data have led to the development of a conceptual model of water movement beneath the Area 5 Radioactive Waste Management Site (RWMS) at the Nevada Test Site (NTS) that differs significantly from the conceptual model of water movement inherent in Resource Conservation and Recovery Act (RCRA) regulations. At the Area 5 RWMS, water fluxes in approximately the upper 75 m (250 ft) of the vadose zone point in the upward direction (rather than downward) which effectively isolates this region from the deep (approximately 250 m (820 ft)) uppermost aquifer. Standard RCRA approaches for detection and containment (groundwater monitoring and double liners/leachate collection/leak detection systems) are not able to fulfill their intended function in this rather unique hydrogeologic environment. In order to better fulfill the waste detection and containment intentions of RCRA for mixed waste disposal at the Area 5 RWMS, the Department of Energy, Nevada Operations Office (DOE/NV) is preparing a single petition for both a waiver from groundwater monitoring and an exemption from double liners with leachate collection/leak detection. DOE/NV proposes in this petition that the containment function of liners and leachate collection is better accomplished by the natural hydrogeologic processes operating in the upper vadose zone; and the detection function of groundwater monitoring and the leak detection system in liners is better fulfilled by an alternative vadose zone monitoring system. In addition, an alternative point of compliance is proposed that will aid in early detection, as well as limit the extent of potential contamination before detection. Finally, special cell design features and operation practices will be implemented to limit leachate formation, especially while the cell is open to the atmosphere during waste emplacement

  12. Hydrological differentiation and spatial distribution of high altitude wetlands in a semi-arid Andean region derived from satellite data

    Directory of Open Access Journals (Sweden)

    M. Otto

    2011-05-01

    Full Text Available High Altitude Wetlands of the Andes (HAWA belong to a unique type of wetland within the semi-arid high Andean region. Knowledge about HAWA has been derived mainly from studies at single sites within different parts of the Andes at only small time scales. On the one hand, HAWA depend on water provided by glacier streams, snow melt or precipitation. On the other hand, they are suspected to influence hydrology through water retention and vegetation growth altering stream flow velocity. We derived HAWA land cover from satellite data at regional scale and analysed changes in connection with precipitation over the last decade. Perennial and temporal HAWA subtypes can be distinguished by seasonal changes of photosynthetically active vegetation (PAV indicating the perennial or temporal availability of water during the year. HAWA have been delineated within a region of 12 800 km2 situated in the Northwest of Lake Titicaca. The multi-temporal classification method used Normalized Differenced Vegetation Index (NDVI and Normalized Differenced Infrared Index (NDII data derived from two Landsat ETM+ scenes at the end of austral winter (September 2000 and at the end of austral summer (May 2001. The mapping result indicates an unexpected high abundance of HAWA covering about 800 km2 of the study region (6 %. Annual HAWA mapping was computed using NDVI 16-day composites of Moderate Resolution Imaging Spectroradiometer (MODIS. Analyses on the relation between HAWA and precipitation was based on monthly precipitation data of the Tropical Rain Measurement Mission (TRMM 3B43 and MODIS Eight Day Maximum Snow Extent data (MOD10A2 from 2000 to 2010. We found HAWA subtype specific dependencies on precipitation conditions. A strong relation exists between perennial HAWA and snow fall (r2: 0.82 in dry austral winter months (June to August and between temporal HAWA and precipitation (r2: 0.75 during austral summer

  13. High seasonal variation in entomologic inoculation rates in Eritrea, a semi-arid region of unstable malaria in Africa.

    Science.gov (United States)

    Shililu, Josephat; Ghebremeskel, Tewolde; Mengistu, Solomon; Fekadu, Helen; Zerom, Mehari; Mbogo, Charles; Githure, John; Novak, Robert; Brantly, Eugene; Beier, John C

    2003-12-01

    Entomologic studies were conducted in eight villages to investigate the patterns of malaria transmission in different ecologic zones in Eritrea. Mosquito collections were conducted for 24 months between September 1999 and January 2002. The biting rates of Anopheles arabiensis were highly seasonal, with activity concentrated in the wet season between June and October in the highlands and western lowlands, and between December and March in the coastal region. The biting rates in the western lowlands were twice as high as in the western escarpment and 20 times higher than in the coastal region. Sporozoite rates were not significantly different among villages. The risk of infection ranged from zero on the coast to 70.6 infective bites per year in the western lowlands. The number of days it would take for an individual to receive an infective bite from an infected An. arabiensis was variable among villages (range = 2.8-203.1 days). The data revealed the presence of only one main malaria transmission period between July and October for the highlands and western lowlands. Peak inoculation rates were recorded in August and September (range = 0.29-43.6 infective bits/person/month) at all sites over the two-year period. The annual entomologic inoculation rates (EIRs) varied greatly depending on year. The EIR profiles indicated that the risk of exposure to infected mosquitoes is highly heterogeneous and seasonal, with high inoculation rates during the rainy season, and with little or no transmission during the dry season. This study demonstrates the need to generate spatial and temporal data on transmission intensity on smaller scales to guide targeted control of malaria operations in semi-arid regions. Furthermore, EIR estimates derived in the present study provide a means of quantifying levels of exposure to infected mosquitoes in different regions of the country and could be important for evaluating the efficacy of vector control measures, since Eritrea has made

  14. ENERGETIC VALUE OF FORAGES FROM SEMI-ARID REGION AND DIGESTIBILITY OF RATIONS FOR NAKED NECK PULLETS

    Directory of Open Access Journals (Sweden)

    ALEX MARTINS VARELA DE ARRUDA

    2014-01-01

    Full Text Available The feeding programs for naked neck chickens in semi-intensive production system from brazilian equatorial semi-arid environment, must consider regional food availability and respective nutritional values. Thus, to evaluate the digestibility and metabolizable energy of alternative forages, it was used 240 naked neck pullets (Isa Label lineage receiving water and ration ad libitum, pair-housed in cages for total collection of excreta on conventional warehouse. It was used a completely randomized design with factorial arrangement (5x2: one control ration (corn and soy meal and other four experimental rations with silk flower hay (Calotropis procera, cassava leafs hay (Manihot esculenta, kills pasture hay (Senna obtusifolia or leucaena leafs hay (Leucaena leucocephala, and all rations were balanced for two growing phases, between 8 and 10 weeks (young pullets and between 14 and 16 weeks of age (old pullets. The values of apparent digestibility of nutrients for all experimental rations were lower than control ration (P <0.05 and it was observed general means of 72.18% for dry matter, 78.12% for crude protein, 66.90% for ether extract, 28.08% for neutral detergent fiber, 18.51% for the acid detergent fiber, 71.64% for gross energy and availability of 15.61% for mineral matter. The general mean of apparent and corrected metabolizable energy of alternative forages was 1217 kcal/ kg and 1108 kcal/kg, respectively, and the higher value was determined for leucaena hay and the lower value for silk flower hay (P <0.05.

  15. Principal coordinate analysis of genotype × environment interaction for grain yield of bread wheat in the semi-arid regions

    Directory of Open Access Journals (Sweden)

    Sabaghnia Naser

    2013-01-01

    Full Text Available Multi-environmental trials have significant main effects and significant multiplicative genotype × environment (GE interaction effect. Principal coordinate analysis (PCOA offers a more appropriate statistical analysis to deal with such situations, compared to traditional statistical methods. Eighteen bread wheat genotypes were grown in four semi-arid regions over three year seasons to study the GE interaction and yield stability and obtained data on grain yield were analyzed using PCOA. Combined analysis of variance indicated that all of the studied effects including the main effects of genotype and environments as well as the GE interaction were highly significant. According to grand means and total mean yield, test environments were grouped to two main groups as high mean yield (H and low mean yield (L. There were five H test environments and six L test environments which analyzed in the sequential cycles. For each cycle, both scatter point diagram and minimum spanning tree plot were drawn. The identified most stable genotypes with dynamic stability concept and based on the minimum spanning tree plots and centroid distances were G1 (3310.2 kg ha-1 and G5 (3065.6 kg ha-1, and therefore could be recommended for unfavorable or poor conditions. Also, genotypes G7 (3047.2 kg ha-1 and G16 (3132.3 kg ha-1 were located several times in the vertex positions of high cycles according to the principal coordinates analysis. The principal coordinates analysis provided useful and interesting ways of investigating GE interaction of barley genotypes. Finally, the results of principal coordinates analysis in general confirmed the breeding value of the genotypes, obtained on the basis of the yield stability evaluation.

  16. Hydrologic cycle and dynamics of aquatic macrophytes in two intermittent rivers of the semi-arid region of Brazil

    Directory of Open Access Journals (Sweden)

    F. Pedro

    Full Text Available The dynamics of aquatic macrophytes in intermittent rivers is generally related to the characteristics of the resistance and resilience of plants to hydrologic disturbances of flood and drought. In the semi-arid region of Brazil, intermittent rivers and streams are affected by disturbances with variable intensity, frequency, and duration throughout their hydrologic cycles. The aim of the present study is to determine the occurrence and variation of biomass of aquatic macrophyte species in two intermittent rivers of distinct hydrologic regimes. Their dynamics were determined with respect to resistance and resilience responses of macrophytes to flood and drought events by estimating the variation of biomass and productivity throughout two hydrologic cycles. Twenty-one visits were undertaken in the rewetting, drying, and drought phases in a permanent puddle in the Avelós stream and two temporary puddles in the Taperoá river, state of Paraíba, Northeast Brazil. The sampling was carried out by using the square method. Floods of different magnitudes occurred during the present study in the river and in the stream. The results showed that floods and droughts are determining factors in the occurrence of macrophytes and in the structure of their aquatic communities. The species richness of the aquatic macrophyte communities was lower in the puddles of the river and stream subject to flood events, when compared to areas where the run-off water is retained. At the beginning of the recolonization process, the intensity of the floods was decisive in the productivity and biomass of the aquatic macrophytes in the Taperoá river and the Avelós stream. In intermediate levels of disturbance, the largest values of productivity and biomass and the shortest time for starting the recolonization process occurred.

  17. The effect of urbanization in an arid region: Formation of a perched water table that causes environmental damages

    Science.gov (United States)

    Karnieli, A.; Issar, A.; Wolf, M.

    1984-03-01

    Construction in a new neighborhood in the israeli town of Dimona, situated in an arid region in the south of the country (150 mm average annual rainfall), resulted in a rise in groundwater levels during the subsequent rainy seasons This caused flooding of shelter basements, soil sliding, and sagging which permanently damaged walls and buildings The neighborhood had been built on continental sands and marls blanketed by loess, on a valley slope near a rocky anticlinal dip-slope Subsurface studies, using piezometer holes and groundwater analyses, revealed the presence of sand lenses alternating with plastic marls, which act as seasonal aquifers with perched water tables Groundwaters obtain high SO{4/-2} and Cl- corrosivity through contact with these nonflushed marls of the Neogene valley fill (Hazeva Formation) The reasons for the rising of groundwater were found to be (a) artificial interference with the natural (pre-construction) drainage system—interception of the hillside runoff by building plots, roads, etc, (b) partial denudation of the loess blanket, increasing the local infiltration and the build-up of local, perched water tables, and (c) corrosion of concrete and steel pipelines, as well as foundations, by prolonged contact with corrosive groundwater, resulting in haphazard but massive leakage Guidelines are proposed for an environmental improvement plan, which would include terracing and planting of the watershed above town to increase evapotranspiration, lowering of the water table by pumping, and diverting the water to suburban parks (groves of saltresistant trees), and replacement of steel and cement pipes by a non-corrodable plastic pipe system

  18. Sustainable land cover and terrain modification to enhance convection and precipitation in the arid region of the United Arab Emirates

    Science.gov (United States)

    Wulfmeyer, V.; Branch, O.; Adebabseh, A.; Temimi, M.

    2017-12-01

    Irrigated plantations and modified terrain can provide a sustainable means of enhancing convective rainfall in arid regions like the United Arab Emirates, or UAE, and can be used to aid ongoing cloud seeding operations through the geographic-localization of seedable cloud formation. The first method, the planting of vast irrigated plantations of hardy desert shrubs, can lead to wind convergence and vertical mixing through increased roughness and modified radiative balances. When upper-air atmospheric instability is present, these phenomena can initiate convection. The second method, increasing the elevation of moderate-sized mountains, is based on the correlation between elevation and the number of summertime convection initiation events observed in the mountains of the UAE and Oman. This augmentation of existing orographic features should therefore increase the likelihood and geographic range of convection initiation events. High-resolution simulations provide a powerful means of assessing the likely impacts of land surface modifications. Previous convection-permitting simulations have yielded some evidential support for these hypotheses, but higher resolutions down to 1 km provide more detail regarding convective processes and land surface representation. Using seasonal simulations with the WRF-NOAHMP land-atmosphere model at a 2.5 km resolution, we identify frequent zones of convergence and atmospheric instability in the UAE and select interesting cases. Using these results, as well as an agricultural feasibility study, we identify optimal plantation positions within the UAE. We then run realistic plantation scenarios for single case studies at 1 km resolution. Using the same cases, we simulate the impact of augmenting mountain elevations on convective processes, with the augmentation being achieved through GIS-based modification of the terrain data. For both methods, we assess the impacts quantitatively and qualitatively, and assess key processes and

  19. Atmospheric reactive nitrogen concentrations at ten sites with contrasting land use in an arid region of central Asia

    Directory of Open Access Journals (Sweden)

    K. H. Li

    2012-10-01

    Full Text Available Atmospheric concentrations of reactive nitrogen (Nr species from 2009 to 2011 are reported for ten sites in Xinjiang, China, an arid region of central Asia. Concentrations of NH3, NO2, particulate ammonium and nitrate (pNH4+ and pNO3 showed large spatial and seasonal variation and averaged 7.71, 9.68, 1.81 and 1.13 μg N m−3, and PM10 concentrations averaged 249.2 μg m−3 across all sites. Lower NH3 concentrations and higher NO2, pNH4+ and pNO3 concentrations were found in winter, reflecting serious air pollution due to domestic heating in winter and other anthropogenic sources such as increased emissions from motor traffic and industry. The increasing order of total concentrations of Nr species was alpine grassland; desert, desert-oasis ecotone; desert in an oasis; farmland; suburban and urban ecosystems. Lower ratios of secondary particles (NH4+ and NO3 were found in the desert and desert-oasis ecotone, while urban and suburban areas had higher ratios, which implied that anthropogenic activities have greatly influenced local air quality and must be controlled.

  20. Effects of different agricultural managements in soil microbial community structure in a semi-arid Mediterranean region.

    Science.gov (United States)

    García-Orenes, Fuensanta; Morugan, Alicia; Mataix-Solera, Jorge; Scow, Kate

    2013-04-01

    Agriculture has been practiced in semi-arid Mediterranean regions for 10.000 years and in many cases these practices have been unsuitable causing land degradation for millennium and an important loss of soil quality. The land management can provide solutions to find the best agricultural practices in order to maintain the soil quality and get a sustainable agriculture model. Microbiological properties are the most sensitive and rapid indicators of soil perturbations and land use managements. The study of microbial community and diversity has an important interest as indicators of changes in soil quality. The main objective of this work was to asses the effect of different agricultural management practices in soil microbial community (evaluated as abundance of phospholipid fatty acids, PLFA). Four different treatments were selected, based on the most commonly practices applied by farmers in the study area, "El Teularet Experimental Station", located at the Enguera Range in the southern part of the Valencia province (eastern Spain). These treatments were: a) ploughing, b) herbicides c) mulch, using the types applied by organic farmers to develop a sustainable agriculture, such as oat straw and d) control that was established as plot where the treatment was abandonment after farming. An adjacent area with the same type of soil, but with natural vegetation was used as a standard or reference high quality soil. Soil samples were taken to evaluate the changes in microbial soil structure, analysing the abundance of PLFA. The results showed a major content of total PLFA in soils treated with oats straw, being these results similar to the content of PLFA in the soil with natural vegetation, also these soils were similar in the distribution of abundance of different PLFA studied. However, the herbicide and tillage treatments showed great differences regarding the soil used as reference (soil under natural vegetation).

  1. Transcription-factor occupancy at HOT regions quantitatively predicts RNA polymerase recruitment in five human cell lines.

    KAUST Repository

    Foley, Joseph W

    2013-10-20

    BACKGROUND: High-occupancy target (HOT) regions are compact genome loci occupied by many different transcription factors (TFs). HOT regions were initially defined in invertebrate model organisms, and we here show that they are a ubiquitous feature of the human gene-regulation landscape. RESULTS: We identified HOT regions by a comprehensive analysis of ChIP-seq data from 96 DNA-associated proteins in 5 human cell lines. Most HOT regions co-localize with RNA polymerase II binding sites, but many are not near the promoters of annotated genes. At HOT promoters, TF occupancy is strongly predictive of transcription preinitiation complex recruitment and moderately predictive of initiating Pol II recruitment, but only weakly predictive of elongating Pol II and RNA transcript abundance. TF occupancy varies quantitatively within human HOT regions; we used this variation to discover novel associations between TFs. The sequence motif associated with any given TF\\'s direct DNA binding is somewhat predictive of its empirical occupancy, but a great deal of occupancy occurs at sites without the TF\\'s motif, implying indirect recruitment by another TF whose motif is present. CONCLUSIONS: Mammalian HOT regions are regulatory hubs that integrate the signals from diverse regulatory pathways to quantitatively tune the promoter for RNA polymerase II recruitment.

  2. Transcription-factor occupancy at HOT regions quantitatively predicts RNA polymerase recruitment in five human cell lines.

    KAUST Repository

    Foley, Joseph W; Sidow, Arend

    2013-01-01

    BACKGROUND: High-occupancy target (HOT) regions are compact genome loci occupied by many different transcription factors (TFs). HOT regions were initially defined in invertebrate model organisms, and we here show that they are a ubiquitous feature of the human gene-regulation landscape. RESULTS: We identified HOT regions by a comprehensive analysis of ChIP-seq data from 96 DNA-associated proteins in 5 human cell lines. Most HOT regions co-localize with RNA polymerase II binding sites, but many are not near the promoters of annotated genes. At HOT promoters, TF occupancy is strongly predictive of transcription preinitiation complex recruitment and moderately predictive of initiating Pol II recruitment, but only weakly predictive of elongating Pol II and RNA transcript abundance. TF occupancy varies quantitatively within human HOT regions; we used this variation to discover novel associations between TFs. The sequence motif associated with any given TF's direct DNA binding is somewhat predictive of its empirical occupancy, but a great deal of occupancy occurs at sites without the TF's motif, implying indirect recruitment by another TF whose motif is present. CONCLUSIONS: Mammalian HOT regions are regulatory hubs that integrate the signals from diverse regulatory pathways to quantitatively tune the promoter for RNA polymerase II recruitment.

  3. Mashhad Wise Water Forum: a path to sustainable water resources management in a semi-arid region of Iran

    Science.gov (United States)

    Tabatabaee, Seyyed Alireza; Neyshaboori, Shahnaz; Basirat, Ali; Tavakoli Aminiyan, Samaneh; Mirbehrooziyan, Ahmad; Sakhdari, Hossein; Shafiei, Mojtaba; Davary, Kamran

    2016-04-01

    Water is key to sustainable development especially in semi-arid regions in which the main source of water provision is groundwater. Water has value from a social, economic and environmental perspective and is required to be managed within a sound, integrated socio-economic and environmental framework. Mashhad, the second big city in Iran, has been faced with rapid growth rates of population and economic activities. The groundwater in Mashhad basin has been overexploited to meet the increasing trend of water demand during the past 20 years. Consequently, the region has faced with water scarcity and water quality problems which originates from inefficient use and poor management. To tackle the water issue on a durable basis, within the economic, ecological, and political constraints (i.e. the integrated water resources management, IWRM concept), a Non-Governmental Organization (NGO), named as Mashhad Wise Water Forum (MWWF), has been established in 2013 that encompasses contribution of experts from academia, industry, and governmental policy-makers. The MWWF considers the UN-Water IWRM spiral conceptual model (which contains four stages: Recognizing and identifying; Conceptualizing; Coordinating and planning; Implementing, Monitoring and Evaluating) by implicating participatory water management (water users' involvement) methods in Mashhad basin. Furthermore, the MWWF has planned to look at all dimensions of water crisis (i.e. physical, economic, policy and institutional) particularly institutional dimension by gathering all stockholders, beneficiaries and experts in different parts of water policy making in Mashhad basin. The MWWF vision for Mashhad basin is achieving to sustainable equilibrium of water resources and consumptions in the basin by the prospect to 2040 year. So far, the MWWF has tried to understand and deal with regional diversity in legal systems as well as conflicts between private interests and public welfare in water allocation and management. At

  4. Photovoltaic systems: A cost competitive option to supply energy to off-grid agricultural communities in arid regions

    International Nuclear Information System (INIS)

    Qoaider, Louy; Steinbrecht, Dieter

    2010-01-01

    The main objective of this work is to investigate the economic feasibility of photovoltaic technology to supply the entire energy demands to off-grid irrigated-farming-based communities in the arid regions. This aims at helping these communities to find practical solutions to cope with the rapid rising electricity generation costs, mainly by diesel generators (gensets). The genset electricity costs are typically affected by the high fossil fuel prices, the fuel transport costs and the intensive operation and maintenance (O and M) requirements. The work was conducted on a representative site from which conclusions could be drawn for similar regions. The case study was performed in the New Kalabsha Village in the Lake Nasser Region (LNR) in southern Egypt. The work involved the technical design and the calculation of the life cycle costs (LCC) of a PV system, which is able to supply the village with its entire energy demand. The PV generator was sized in such a way to daily pump 111 000 m 3 of lake water to irrigate 1260 ha acreage plots and to electrify the adjacent village's households. The required pumps were designed to pump the fluctuating lake's water for a maximum differential head of 17 m in four different locations. Consequently, water from the four pumping stations flows freely by gravity forces to the different plots through overhead open canals. The electricity generation costs and the performance of the designed PV generator were compared with those of an equivalent diesel generator (genset) in order to prove its competitiveness. With this regard, the real market value of the diesel fuel of 86.55 c Euro l -1 was considered for calculating the costs of genset generated electricity. The results showed that the genset electricity unit costs 39 c Euro kW h -1 while a unit of PV electricity costs only 13 c Euro kW h -1 for the equivalent system size and project lifetime. Furthermore, the subsidised genset electricity cost was calculated to be 12 c Euro kW h

  5. Index of Relative Importance of the Dietary Proportions of Sloth Bear (Melursus ursinus in Semi-Arid Region

    Directory of Open Access Journals (Sweden)

    Tana P. MEWADA

    2015-09-01

    Full Text Available Characterisations of the Sloth bear (Melursus ursinus diet during three distinguished seasons (monsoon, winter and summer in the semi-arid region of western India was under study. Diet was estimated using scat analysis, based on the calculation of Index of Relative Importance (IRI in order to determine the contribution of different food items in the Sloth bear diet. Sloth bears were observed to feed on a wide variety of prey items. They are specialized on insect prey, particularly termites or ants, and are considered as myrmecophagous. The myrmecophagousis character was confirmed by the highest score of insect part (IRI = 21.37 from the samples (n = 566, which was followed by Diospyros melanoxylon (IRI Score 13.51, Ficus spp. (IRI score 12.69 and Cassia fistula (IRI Score 10.13. Sloth bear dietary proportions varied among the three seasons under the study interval. Data suggested that the Sloth bear is essentially behaving as an omnivore, having similar diet (in terms of high incidence of wild fruits and insects with the bears inhabiting semi-arid regions. The opportunistic and generalist strategy of selecting diet ingredients has probably helped the species to survive in semi-arid habitat across the North Gujarat.

  6. Tackling the salinity-pollution nexus in coastal aquifers from arid regions using nitrate and boron isotopes.

    Science.gov (United States)

    Re, V; Sacchi, E

    2017-05-01

    Salinization and nitrate pollution are generally ascertained as the main issues affecting coastal aquifers worldwide. In arid zones, where agricultural activities also result in soil salinization, both phenomena tend to co-exist and synergically contribute to alter groundwater quality, with severe negative impacts on human populations and natural ecosystems' wellbeing. It becomes therefore necessary to understand if and to what extent integrated hydrogeochemical tools can help in distinguishing among possible different salinization and nitrate contamination origins, in order to provide adequate science-based support to local development and environmental protection. The alluvial plain of Bou-Areg (North Morocco) extends over about 190 km 2 and is separated from the Mediterranean Sea by the coastal Lagoon of Nador. Its surface is covered for more than 60% by agricultural activities, although the region has been recently concerned by urban population increase and tourism expansion. All these activities mainly rely on groundwater exploitation and at the same time are the main causes of both aquifer and lagoon water quality degradation. For this reason, it was chosen as a case study representative of the typical situation of coastal aquifers in arid zones worldwide, where a clear identification of salinization and pollution sources is fundamental for the implementation of locally oriented remedies and long-term management strategies. Results of a hydrogeochemical investigation performed between 2009 and 2011 show that the Bou-Areg aquifer presents high salinity (often exceeding 100 mg/L in TDS) due to both natural and anthropogenic processes. The area is also impacted by nitrate contamination, with concentrations generally exceeding the WHO statutory limits for drinking water (50 mg/L) and reaching up to about 300 mg/L, in both the rural and urban/peri-urban areas. The isotopic composition of dissolved nitrates (δ 15 N NO3 and δ 18 O NO ) was used to constrain

  7. GHGs (greenhouse gases) emission and economic analysis of a GCRES (grid-connected renewable energy system) in the arid region, Algeria

    International Nuclear Information System (INIS)

    Saheb Koussa, Djohra; Koussa, Mustapha

    2016-01-01

    This paper presents a method for economic evaluation and GHGs (greenhouse gases) emissions calculation from a GCRES (grid-connected renewable energy system). An investigation is made on large-scale operations of 67 MWh/day GCRES. A comparison is performed between a GCRES and a standard grid operation focusing on environmental and economic impacts. Emissions and the Renewable energy generation fraction (RF) of total energy consumption are calculated as the main environmental indicators. Costs including NPC (net present cost), COE (cost of energy) and payback period are calculated as the economic indicators. Using the hourly mean global solar irradiance, temperature and wind speed data relative to In Salah and Adrar locations characterized by an arid and hot climate according to the Koppen–Geiger climate classification, a long-term continuous implementation of hybrid renewable energy systems are simulated using HOMER software and are discussed. As results, it is observed that a GCRES reduce 30% and 35% of GHGs emission, and 81% and 76% of COE during the operation phase respectively for In Salah and Adrar. Investments in GCRES should be considered only by planning to produce parts of the equipment locally, which leads to significantly reduce the costs and, consequently, the emissions. - Highlights: • Grid-connected renewable energy system (GCRES). • Economic evaluation and greenhouse gases (GHGs) emissions calculation. • In Salah and Adrar are taken as two examples of the famous Algerian arid land. • The climatic data are used to simulate the long-term implementation of the system.

  8. Influence of household biogas digester use on household energy consumption in a semi-arid rural region of northwest China

    International Nuclear Information System (INIS)

    Ding, Wenguang; Niu, Hewen; Chen, Jinsong; Du, Jun; Wu, Yang

    2012-01-01

    .71 yuan per mu. The utilization of biogas in rural semi-arid regions of China is a potentially clean development mechanism (CDM) and has profound implications for applied energy.

  9. Survey on the construction of realization scenario of large-scale revegetation of arid regions; Daikibo ryokuka no jitsugenka scenario sakusei ni kansuru chosa

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    In order to fix carbon dioxide as a measure to mitigate global warming, research of large-scale revegetation of arid regions has been conducted toward the ultimate goals of systematizing revegetation technologies centered on securing and using water resources, evaluating the feasibility of arid revegetation by extending the viewpoint to examine even rainfall increase by artificial means, and establishing a strategic program for large-scale revegetation. A trial revegetation feasibility map was made for a selected target region in Western Australia, and rough revegetation steps were formulated. Selection of proper region, introduction of technology, and planning were conducted by grasping environment of the target revegetation region. As a result, it was found that growth of plants is vigorous at the catchment areas due to the surface water transfer along the topography of surface in spite of poor rainfall. Obstruction of plant growth is partly caused by the corrosion of soil and accumulation of salt, but mainly caused by the shortage of water. Based on these data, ranking of proper regions was evaluated. When the technology is introduced in the region with A-rank, several times of water can be collected. 60 refs., 61 figs., 30 tabs.

  10. Land Surface Model and Particle Swarm Optimization Algorithm Based on the Model-Optimization Method for Improving Soil Moisture Simulation in a Semi-Arid Region.

    Science.gov (United States)

    Yang, Qidong; Zuo, Hongchao; Li, Weidong

    2016-01-01

    Improving the capability of land-surface process models to simulate soil moisture assists in better understanding the atmosphere-land interaction. In semi-arid regions, due to limited near-surface observational data and large errors in large-scale parameters obtained by the remote sensing method, there exist uncertainties in land surface parameters, which can cause large offsets between the simulated results of land-surface process models and the observational data for the soil moisture. In this study, observational data from the Semi-Arid Climate Observatory and Laboratory (SACOL) station in the semi-arid loess plateau of China were divided into three datasets: summer, autumn, and summer-autumn. By combing the particle swarm optimization (PSO) algorithm and the land-surface process model SHAW (Simultaneous Heat and Water), the soil and vegetation parameters that are related to the soil moisture but difficult to obtain by observations are optimized using three datasets. On this basis, the SHAW model was run with the optimized parameters to simulate the characteristics of the land-surface process in the semi-arid loess plateau. Simultaneously, the default SHAW model was run with the same atmospheric forcing as a comparison test. Simulation results revealed the following: parameters optimized by the particle swarm optimization algorithm in all simulation tests improved simulations of the soil moisture and latent heat flux; differences between simulated results and observational data are clearly reduced, but simulation tests involving the adoption of optimized parameters cannot simultaneously improve the simulation results for the net radiation, sensible heat flux, and soil temperature. Optimized soil and vegetation parameters based on different datasets have the same order of magnitude but are not identical; soil parameters only vary to a small degree, but the variation range of vegetation parameters is large.

  11. Heavy metal pollutionof soil and new approch to its remediation: Research experiences in arid region in Morocco

    International Nuclear Information System (INIS)

    El Hari, A.; Lekouch, N.; Chaik, M.; El Fadeli, S.; Sedki, A.

    2012-01-01

    Full text: With climate change and water scarcity remarkable for agricultural soils in the countries of North Africa, pollution with heavy metals represent a great danger for aquatic as well as terrestrial ecosystems. Indeed, they are persistent and non-biodegradable in the environment. When in excess, these metals may influence the soil's biochemical and physico-chemical characteristics, or disturb plants' physiology and contaminate alimentary chains. Therefore, a possible action for rehabilitation of contaminated sites would be an original approach: phytostabilisation. This technique, which is used in Europe but not yet in Morocco, consists of using plants in order to stop soil contaminant migration towards the aquifer. The objective of this study is to try to find vegetal species that are both adapted to the arid climate of Marrakech and capable of purifying the soil and the ground water. In addition, we have chosen to study waters and soils of two sites with different sources of contamination, both located in the surroundings of Marrakech, one representing the used water zone, namely the region of El Azzouzia and the other being the mining zone called D raa Lasfar . On the other hand, thanks to germination and growing tests, we have tried to apply the phytostabilisation technique on different soils by selecting varieties, among 15 vegetal species, which can resist the presence of heavy metals the most, especially Cadmium, and accumulate heavy metals in order to play a purifying role. Our study results have shown that among these 15 vegetal species, only three show the highest growth and most important resistance to Cadmium. The three vegetal species in question are Corn, Wheat and Trigonella. The study has also been able to demonstrate that among these three species, Trigonella is the most hyper accumulative of Zinc and Cadmium. It could therefore be suggested to be a means of phytostabilisation on polluted soils of the city and surroundings of Marrakech

  12. Analysis of trend in temperature and rainfall time series of an Indian arid region: comparative evaluation of salient techniques

    Science.gov (United States)

    Machiwal, Deepesh; Gupta, Ankit; Jha, Madan Kumar; Kamble, Trupti

    2018-04-01

    This study investigated trends in 35 years (1979-2013) temperature (maximum, Tmax and minimum, Tmin) and rainfall at annual and seasonal (pre-monsoon, monsoon, post-monsoon, and winter) scales for 31 grid points in a coastal arid region of India. Box-whisker plots of annual temperature and rainfall time series depict systematic spatial gradients. Trends were examined by applying eight tests, such as Kendall rank correlation (KRC), Spearman rank order correlation (SROC), Mann-Kendall (MK), four modified MK tests, and innovative trend analysis (ITA). Trend magnitudes were quantified by Sen's slope estimator, and a new method was adopted to assess the significance of linear trends in MK-test statistics. It was found that the significant serial correlation is prominent in the annual and post-monsoon Tmax and Tmin, and pre-monsoon Tmin. The KRC and MK tests yielded similar results in close resemblance with the SROC test. The performance of two modified MK tests considering variance-correction approaches was found superior to the KRC, MK, modified MK with pre-whitening, and ITA tests. The performance of original MK test is poor due to the presence of serial correlation, whereas the ITA method is over-sensitive in identifying trends. Significantly increasing trends are more prominent in Tmin than Tmax. Further, both the annual and monsoon rainfall time series have a significantly increasing trend of 9 mm year-1. The sequential significance of linear trend in MK test-statistics is very strong (R 2 ≥ 0.90) in the annual and pre-monsoon Tmin (90% grid points), and strong (R 2 ≥ 0.75) in monsoon Tmax (68% grid points), monsoon, post-monsoon, and winter Tmin (respectively 65, 55, and 48% grid points), as well as in the annual and monsoon rainfalls (respectively 68 and 61% grid points). Finally, this study recommends use of variance-corrected MK test for the precise identification of trends. It is emphasized that the rising Tmax may hamper crop growth due to enhanced

  13. [Effect of shifting sand burial on evaporation reduction and salt restraint under saline water irrigation in extremely arid region].

    Science.gov (United States)

    Zhang, Jian-Guo; Zhao, Ying; Xu, Xin-Wen; Lei, Jia-Qiang; Li, Sheng-Yu; Wang, Yong-Dong

    2014-05-01

    The Taklimakan Desert Highway Shelterbelt is drip-irrigated with high saline groundwater (2.58-29.70 g x L(-1)), and shifting sand burial and water-salt stress are most common and serious problems in this region. So it is of great importance to study the effect of shifting sand burial on soil moisture evaporation, salt accumulation and their distribution for water saving, salinity restraint, and suitable utilization of local land and water resources. In this study, Micro-Lysimeters (MLS) were used to investigate dynamics of soil moisture and salt under different thicknesses of sand burial (1, 2, 3, 4, and 5 cm), and field control experiments of drip-irrigation were also carried out to investigate soil moisture and salt distribution under different thicknesses of shifting sand burial (5, 10, 15, 20, 25, 30, 35, and 40 cm). The soil daily and cumulative evaporation decreased with the increase of sand burial thickness in MLS, cumulative evaporation decreased by 2.5%-13.7% compared with control. And evaporative inhibiting efficiency increased with sand burial thickness, evaporative inhibiting efficiency of 1-5 cm sand burial was 16.7%-79.0%. Final soil moisture content beneath the interface of sand burial increased with sand burial thickness, and it increased by 2.5%-13.7% than control. The topsoil EC of shifting sand in MLS decreased by 1.19-6.00 mS x cm(-1) with the increasing sand burial thickness, whereas soil salt content beneath the interface in MLS increased and amplitude of the topsoil salt content was higher than that of the subsoil. Under drip-irrigation with saline groundwater, average soil moisture beneath the interface of shifting sand burial increased by 0.4% -2.0% compare with control, and the highest value of EC was 7.77 mS x cm(-1) when the sand burial thickness was 10 cm. The trend of salt accumulation content at shifting sand surface increased firstly, and then decreased with the increasing sand burial thickness. Soil salt contents beneath the

  14. Water, land, climate change and agrarian livelihood in an arid region riparian corridor: Rayón, Sonora, Mexico

    Science.gov (United States)

    Lee, R.; Scott, C. A.; Curl, K.; House-Peters, L.; Buechler, S.

    2012-12-01

    Results of recent fieldwork in Rayón, Sonora, Mexico (funded by NSF's "Strengthening Resilience of Arid Region Riparian Corridors") indicate that the coupled natural and human (CNH) system that has persisted since the town's founding in 1626 is being degraded and destabilised by a confluence of social and ecological pressures. System change or loss of key system services and products has important implications for ecological services and human economic activity in the riparian corridor. Less water quantity is the primary factor responsible for driving system degradation and change. Drought caused by climate change is widely perceived by agriculturists as responsible for reduced water quantity in the riparian area. Reductions in water quantity are so severe that the once perennial Rio San Miguel did not run during 2012's summer months for the first time in residents' memory. Ninety-percent of wells are dry. Fields irrigated by surface-water acequias were not planted. Starvation or dehydration has thinned herd sizes. Residents fear they will lose the ability to practice their traditional livelihoods: ranching, farming and cheese production. Drought conditions and resource management in response to climatic change have had a net negative impact on ecological services. Agriculturists have responded to less forage and pasture for cattle by clearing mesquite forests, putting land into production, and increasing water demand. From interviews it appears this process is cyclical: agriculturists widely believe access to more water or an end to the drought are the only ways to improve conditions. Interviews also reveal (a) agriculturists view technology, especially that which is able to improve water-use efficiency, as means to reduce stress in the CNH system and (b) a holistic view that couples natural well-being to human well-being is absent from the majority of respondents' worldviews. Technological and adoption of holistic perceptions are adaptations that may potentially

  15. Lower Silurian `hot shales' in North Africa and Arabia: regional distribution and depositional model

    Science.gov (United States)

    Lüning, S.; Craig, J.; Loydell, D. K.; Štorch, P.; Fitches, B.

    2000-03-01

    Lowermost Silurian organic-rich (`hot') shales are the origin of 80-90% of Palaeozoic sourced hydrocarbons in North Africa and also played a major role in petroleum generation on the Arabian Peninsula. In most cases, the shales were deposited directly above upper Ordovician (peri-) glacial sandstones during the initial early Silurian transgression that was a result of the melting of the late Ordovician icecap. Deposition of the main organic-rich shale unit in the North African/Arabian region was restricted to the earliest Silurian Rhuddanian stage ( acuminatus, atavus and probably early cyphus graptolite biozones). During this short period (1-2 m.y.), a favourable combination of factors existed which led to the development of exceptionally strong oxygen-deficiency in the area. In most countries of the study area, the post-Rhuddanian Silurian shales are organically lean and have not contributed to petroleum generation. The distribution and thickness of the basal Silurian `hot' shales have been mapped in detail for the whole North African region, using logs from some 300 exploration wells in Libya, Tunisia, Algeria and Morocco. In addition, all relevant, accessible published and unpublished surface and subsurface data of the lower Silurian shales in North Africa and Arabia have been reviewed, including sedimentological, biostratigraphic and organic geochemical data. The lowermost Silurian hot shales of northern Gondwana are laterally discontinuous and their distribution and thickness were controlled by the early Silurian palaeorelief which was shaped mainly by glacial processes of the late Ordovician ice age and by Pan-African and Infracambrian compressional and extensional tectonism. The thickest and areally most extensive basal Silurian organic-rich shales in North Africa occur in Algeria, Tunisia and western Libya, while on the Arabian Peninsula they are most prolific in Saudi Arabia, Oman, Jordan and Iraq. The hot shales were not deposited in Egypt, which was a

  16. HOT PLASMA FROM SOLAR ACTIVE-REGION CORES: CONSTRAINTS FROM THE HINODE X-RAY TELESCOPE

    Energy Technology Data Exchange (ETDEWEB)

    Schmelz, J. T. [USRA, 7178 Columbia Gateway Drive, Columbia, MD 21046 (United States); Christian, G. M.; Matheny, P. O., E-mail: jschmelz@usra.edu [Physics Department, University of Memphis, Memphis, TN 38152 (United States)

    2016-12-20

    Mechanisms invoked to heat the solar corona to millions of degrees kelvin involve either magnetic waves or magnetic reconnections. Turbulence in the convection zone produces MHD waves, which travel upward and dissipate. Photospheric motions continuously build up magnetic energy, which is released through magnetic reconnection. In this paper, we concentrate on hot non-flaring plasma with temperatures of 5 MK <  T  < 10 MK because it is one of the few observables for which wave and reconnection models make different predictions. Wave models predict no (or little) hot plasma, whereas reconnection models predict it, although in amounts that are challenging to detect with current instrumentation. We used data from the X-ray Telescope (XRT) and the Atmospheric Imaging Assembly (AIA). We requested a special XRT observing sequence, which cycled through the thickest XRT filter several times per hour so we could average these images and improve the signal-to-noise. We did differential emission measure (DEM) analysis using the time-averaged thick-filter data as well as all available channels from both the XRT and AIA for regions observed on 2014 December 11. Whereas our earlier work was only able to determine that plasma with a temperature greater than 5 MK was present , we are now able to find a well-constrained DEM distribution. We have therefore added a strong observational constraint that must be explained by any viable coronal heating model. Comparing state-of-the-art wave and reconnection model predictions, we can conclude that reconnection is heating the hot plasma in these active regions.

  17. CHEMICAL SEGREGATION TOWARD MASSIVE HOT CORES: THE AFGL2591 STAR-FORMING REGION

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Serra, I.; Zhang, Q. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Viti, S. [Department of Physics and Astronomy, University College London, Gower Place, London WC1E 6BT (United Kingdom); Martin-Pintado, J. [Centro de Astrobiologia (CSIC/INTA), Ctra. de Torrejon a Ajalvir km 4, E-28850 Torrejon de Ardoz, Madrid (Spain); De Wit, W.-J., E-mail: ijimenez-serra@cfa.harvard.edu, E-mail: qzhang@cfa.harvard.edu, E-mail: sv@star.ucl.ac.uk, E-mail: jmartin@cab.inta-csic.es, E-mail: wdewit@eso.org [European Southern Observatory, Alonso de Cordova 3107, Vitacura, Santiago (Chile)

    2012-07-01

    We present high angular resolution observations (0.''5 Multiplication-Sign 0.''3) carried out with the Submillimeter Array (SMA) toward the AFGL2591 high-mass star-forming region. Our SMA images reveal a clear chemical segregation within the AFGL2591 VLA 3 hot core, where different molecular species (Types I, II, and III) appear distributed in three concentric shells. This is the first time that such a chemical segregation is ever reported at linear scales {<=}3000 AU within a hot core. While Type I species (H{sub 2}S and {sup 13}CS) peak at the AFGL2591 VLA 3 protostar, Type II molecules (HC{sub 3}N, OCS, SO, and SO{sub 2}) show a double-peaked structure circumventing the continuum peak. Type III species, represented by CH{sub 3}OH, form a ring-like structure surrounding the continuum emission. The excitation temperatures of SO{sub 2}, HC{sub 3}N, and CH{sub 3}OH (185 {+-} 11 K, 150 {+-} 20 K, and 124 {+-} 12 K, respectively) show a temperature gradient within the AFGL2591 VLA 3 envelope, consistent with previous observations and modeling of the source. By combining the H{sub 2}S, SO{sub 2}, and CH{sub 3}OH images, representative of the three concentric shells, we find that the global kinematics of the molecular gas follow Keplerian-like rotation around a 40 M{sub Sun} star. The chemical segregation observed toward AFGL2591 VLA 3 is explained by the combination of molecular UV photodissociation and a high-temperature ({approx}1000 K) gas-phase chemistry within the low extinction innermost region in the AFGL2591 VLA 3 hot core.

  18. Dew measurement and estimation of rain-fed jujube (Zizyphus jujube Mill) in a semi-arid loess hilly region of China

    Institute of Scientific and Technical Information of China (English)

    WANG Xing; GAO Zhiyong; WANG Youke; Wang Zhi; JIN Shanshan

    2017-01-01

    Dew is an important water source for plants in arid and semi-arid regions.However,information on dew is scarce in such regions.In this study,we explored dew formation,amount,and duration of rain-fed jujube (Zi(w)phus jujube Mill) trees in a semi-arid loess hilly region of China (i.e.,Mizhi County).The data included dew intensity and duration,relative humidity,temperature,and wind speed measured from 26 July to 23 October,2012 and from 24 June to 17 October,2013 using a micro-climate system (including dielectric leaf wetness sensors,VP-3 Relative Humidity/Temperature Sensor,High Resolution Rain Gauge,and Davis Cup Anemometer).The results show that atmospheric conditions of relative humidity of >78% and dew point temperature of 1℃C-3℃C are significantly favorable to dew formation.Compared with the rainfall,dew was characterized by high frequency,strong stability,and long duration.Furthermore,heavy dew accounted for a large proportion of the total amount.The empirical models (i.e.,relative humidity model (RH model) and dew point depression model (DPD model)) for daily dew duration estimation performed well at 15-rain intervals,with low errors ranging between 1.29 and 1.60 h,respectively.But it should be noted that the models should be calibrated firstly by determining the optimal thresholds of relatively humidity for RH model and dew point depression for DPD model.For rain-fed jujube trees in the semi-arid loess hilly regions of China,the optimal threshold of relative humidity was 78%,and the optimal upper and lower thresholds of dew point depression were 1℃C and 5℃C,respectively.The study further demonstrates that dew is an important water resource that cannot be ignored for rain-fed jujube trees and may affect water balance at regional scales.

  19. Effects of 4D-Var Data Assimilation Using Remote Sensing Precipitation Products in a WRF Model over the Complex Terrain of an Arid Region River Basin

    Directory of Open Access Journals (Sweden)

    Xiaoduo Pan

    2017-09-01

    Full Text Available Individually, ground-based, in situ observations, remote sensing, and regional climate modeling cannot provide the high-quality precipitation data required for hydrological prediction, especially over complex terrains. Data assimilation techniques can be used to bridge the gap between observations and models by assimilating ground observations and remote sensing products into models to improve precipitation simulation and forecasting. However, only a small portion of satellite-retrieved precipitation products assimilation research has been implemented over complex terrains in an arid region. Here, we used the weather research and forecasting (WRF model to assimilate two satellite precipitation products (The Tropical Rainfall Measuring Mission: TRMM 3B42 and Fengyun-2D: FY-2D using the 4D-Var data assimilation method for a typical inland river basin in northwest China’s arid region, the Heihe River Basin, where terrains are very complex. The results show that the assimilation of remote sensing precipitation products can improve the initial WRF fields of humidity and temperature, thereby improving precipitation forecasting and decreasing the spin-up time. Hence, assimilating TRMM and FY-2D remote sensing precipitation products using WRF 4D-Var can be viewed as a positive step toward improving the accuracy and lead time of numerical weather prediction models, particularly over regions with complex terrains.

  20. Study on Applicability of Conceptual Hydrological Models for Flood Forecasting in Humid, Semi-Humid Semi-Arid and Arid Basins in China

    Directory of Open Access Journals (Sweden)

    Guangyuan Kan

    2017-09-01

    Full Text Available Flood simulation and forecasting in various types of watersheds is a hot issue in hydrology. Conceptual hydrological models have been widely applied to flood forecasting for decades. With the development of economy, modern China faces with severe flood disasters in all types of watersheds include humid, semi-humid semi-arid and arid watersheds. However, conceptual model-based flood forecasting in semi-humid semi-arid and arid regions is still challenging. To investigate the applicability of conceptual hydrological models for flood forecasting in the above mentioned regions, three typical conceptual models, include Xinanjiang (XAJ, mix runoff generation (MIX and northern Shannxi (NS, are applied to 3 humid, 3 semi-humid semi-arid, and 3 arid watersheds. The rainfall-runoff data of the 9 watersheds are analyzed based on statistical analysis and information theory, and the model performances are compared and analyzed based on boxplots and scatter plots. It is observed the complexity of drier watershed data is higher than that of the wetter watersheds. This indicates the flood forecasting is harder in drier watersheds. Simulation results indicate all models perform satisfactorily in humid watersheds and only NS model is applicable in arid watersheds. Model with consideration of saturation excess runoff generation (XAJ and MIX perform better than the infiltration excess-based NS model in semi-humid semi-arid watersheds. It is concluded more accurate mix runoff generation theory, more stable and efficient numerical solution of infiltration equation and rainfall data with higher spatial-temporal resolution are main obstacles for conceptual model-based flood simulation and forecasting.

  1. Accumulation of Carbonates Contributes to Coastal Vegetated Ecosystems Keeping Pace With Sea Level Rise in an Arid Region (Arabian Peninsula)

    KAUST Repository

    Saderne, Vincent; Cusack, Michael; Almahasheer, Hanan; Serrano, Oscar; Masqué , Pere; Arias-Ortiz, Ariane; Krishnakumar, Periyadan Kadinjappalli; Rabaoui, Lotfi; Qurban, Mohammad Ali; Duarte, Carlos M.

    2018-01-01

    Anthropogenic sea level rise (SLR) presents one of the greatest risks to human lives and infrastructures. Coastal vegetated ecosystems, that is, tidal marshes, seagrass meadows, and mangrove forests, elevate the seabed through soil accretion, providing a natural coastline protection against SLR. The soil accretion of these ecosystems has never been assessed in hot desert climate regions, where water runoff is negligible. However, tropical marine ecosystems are areas of intense calcification that may constitute an important source of sediment supporting seabed elevation, compensating for the lack of terrestrial inputs. We estimated the long-term (C-centennial) and short-term (Pb-20th century) soil accretion rates (SARs) and inorganic carbon (C) burial in coastal vegetated ecosystems of the Saudi coasts of the central Red Sea and the Arabian Gulf. Short-term SARs (±SE) in mangroves of the Red Sea (0.27 ± 0.22 cm/year) were twofold the SLR for that region since 1925 (0.13 cm/year). In the Arabian Gulf, only mangrove forest SAR is equivalent to local SLR estimates for the period 1979-2007 (0.21 ± 0.09 compared to 0.22 ± 0.05 cm/year, respectively). Long-term SARs are comparable or higher than the global estimates of SLR for the late Holocene (0.01 cm/year). In all habitats of the Red Sea and Arabian Gulf, SARs are supported by high carbonate accretion rates, comprising 40% to 60% of the soil volume. Further studies on the role of carbonates in coastal vegetated ecosystems are required to understand their role in adaptation to SLR.

  2. Accumulation of Carbonates Contributes to Coastal Vegetated Ecosystems Keeping Pace With Sea Level Rise in an Arid Region (Arabian Peninsula)

    KAUST Repository

    Saderne, Vincent

    2018-04-12

    Anthropogenic sea level rise (SLR) presents one of the greatest risks to human lives and infrastructures. Coastal vegetated ecosystems, that is, tidal marshes, seagrass meadows, and mangrove forests, elevate the seabed through soil accretion, providing a natural coastline protection against SLR. The soil accretion of these ecosystems has never been assessed in hot desert climate regions, where water runoff is negligible. However, tropical marine ecosystems are areas of intense calcification that may constitute an important source of sediment supporting seabed elevation, compensating for the lack of terrestrial inputs. We estimated the long-term (C-centennial) and short-term (Pb-20th century) soil accretion rates (SARs) and inorganic carbon (C) burial in coastal vegetated ecosystems of the Saudi coasts of the central Red Sea and the Arabian Gulf. Short-term SARs (±SE) in mangroves of the Red Sea (0.27 ± 0.22 cm/year) were twofold the SLR for that region since 1925 (0.13 cm/year). In the Arabian Gulf, only mangrove forest SAR is equivalent to local SLR estimates for the period 1979-2007 (0.21 ± 0.09 compared to 0.22 ± 0.05 cm/year, respectively). Long-term SARs are comparable or higher than the global estimates of SLR for the late Holocene (0.01 cm/year). In all habitats of the Red Sea and Arabian Gulf, SARs are supported by high carbonate accretion rates, comprising 40% to 60% of the soil volume. Further studies on the role of carbonates in coastal vegetated ecosystems are required to understand their role in adaptation to SLR.

  3. Modelling rainfall runoff relations using HEC-HMS in a semi-arid region: Case study in Ain Sefra watershed, Ksour Mountains (SW Algeria)

    OpenAIRE

    Derdour Abdessamed; Bouanani Abderrazak; Babahamed Kamila

    2018-01-01

    Ain Sefra is one of the Algerian cities that had been experienced several devastating floods during the past 100 years. The purpose of this study is to simulate runoff in the semi-arid region of Ain Sefra watershed through the employing of the Hydrologic Engineering Center – Hydrologic Modelling System (HEC-HMS). In this paper, the frequency storm is used for the meteorological model, the Soil Conservation Service – curve number (SCS-CN) is selected to calculate the loss rate and Soil Conserv...

  4. Yield and quality responses of drip-irrigated spinach to different irrigation quantities in a semi-arid region with a high altitude

    Directory of Open Access Journals (Sweden)

    Yasemin KUSLU

    2016-09-01

    Full Text Available The effect of different irrigation quantities on the growth, marketable yield, crop quality (antioxidant activity, mineral and total phenolic content and irrigation water use efficiency (IWUE of spinach grown in a semi-arid region of high altitude (1795 m a.s.l. was determined. Plants were irrigated with three different irrigation quantities which determined considering 100 (I1, 85 (I2 and 70% (I3 of the evaporation obtained from a Class A pan. Irrigation quantities in the I1, I2 and I3 treatments as two years average were 290, 264.3 and 238.6 mm, respectively. The I1 treatment provided the highest growth, marketable yield (28.06 t*ha-1 and IWUE (9.7 kg*m-3. However, mineral and total phenolic content and antioxidant activity in the leaves of spinach were significantly higher under lower water application conditions. The I2 treatment resulted with the highest antioxidant activity and content of N, K, Mg, Na, Fe, Cu and total phenolics. As a result of the study, I1 treatment in spinach production could be suitable for water sufficient regions due to higher yield and IWUE. However, I2 treatment may be more appropriate for water scarce semi-arid regions of high altitude for obtaining higher minerals and antioxidant activity.

  5. Contamination risk and drinking water protection for a large-scale managed aquifer recharge site in a semi-arid karst region, Jordan

    Science.gov (United States)

    Xanke, Julian; Liesch, Tanja; Goeppert, Nadine; Klinger, Jochen; Gassen, Niklas; Goldscheider, Nico

    2017-09-01

    Karst aquifers in semi-arid regions are particularly threatened by surface contamination, especially during winter seasons when extremely variable rainfall of high intensities prevails. An additional challenge is posed when managed recharge of storm water is applied, since karst aquifers display a high spatial variability of hydraulic properties. In these cases, adapted protection concepts are required to address the interaction of surface water and groundwater. In this study a combined protection approach for the surface catchment of the managed aquifer recharge site at the Wala reservoir in Jordan and the downstream Hidan wellfield, which are both subject to frequent bacteriological contamination, is developed. The variability of groundwater quality was evaluated by correlating contamination events to rainfall, and to recharge from the reservoir. Both trigger increased wadi flow downstream of the reservoir by surface runoff generation and groundwater seepage, respectively. A tracer test verified the major pathway of the surface flow into the underground by infiltrating from pools along Wadi Wala. An intrinsic karst vulnerability and risk map was adapted to the regional characteristics and developed to account for the catchment separation by the Wala Dam and the interaction of surface water and groundwater. Implementation of the proposed protection zones for the wellfield and the reservoir is highly recommended, since the results suggest an extreme contamination risk resulting from livestock farming, arable agriculture and human occupation along the wadi. The applied methods can be transferred to other managed aquifer recharge sites in similar karstic environments of semi-arid regions.

  6. Jojoba - a promising plant for the semi-arid regions. [North America, plants, seeds, oils, waxes, growth, cultivation, lubricants, guayule, mesquite

    Energy Technology Data Exchange (ETDEWEB)

    Yermanos, D.M.

    1979-01-01

    As a result of the world-wide concern for conservation of resources and for the development of new renewable resources a great deal of attention has been directed towards the development of jojoba as a potential new crop for semi-arid regions. Jojoba grows wild in the Southwestern U.S. and N. Mexico, in areas where the annual precipitation is 4''-15''. Under cultivation it appears to grow satisfactorily in areas of marginal soil fertility, high salinity and high atmospheric temperatures. It appears to have no major natural enemies and to be tolerant to chemical treatments, if they were to become necessary. It is perennial with an assumed life span in excess of 150 years. Jojoba seed has an average weight of about 0.5 grams per seed, and it contains a unique liquid wax which is a superior lubricant and a potential replacement of whale oil, obtained from the sperm whale, and endangered species. Thus, jojoba has a double appeal, first as a potential crop of semi-arid regions requiring low cultural and energy inputs and second as a source of a valuable commodity. It should be pointed out that a cheap and abundant source of lubricants will disappear when our stock of fossil fuels are exhausted and that none of our new sources of energy have lubricants as by-products. Finally, jojoba could be grown with other companion crops such as guayule or mesquite for more diversified farming.

  7. Calibration techniques for the hot wire anemometer in a low velocity region

    International Nuclear Information System (INIS)

    Fujimura, Kaoru; Kawamura, Hiroshi

    1980-03-01

    In connection with experiments on coolant flow in the core of multi-purpose VHTR, a low-velocity calibration wind tunnel was made, and techniques for the hot wire anemometer in the air were investigated. Following are the results. 1) A technique using the frequency of von Karman vortex street is not recommended because of the irregular mode in a low velocity region. 2) A Pitot tube is valid only for the flow velocities larger than 1 m/s. 3) The thermal trace technique is suitable in a relatively wide range of velocity, if velocity defect in the wake is compensated for. When flow velocity is larger than 1 m/s, the thermal trace technique is consistent with the Pitot tube method. (author)

  8. Analysing the mechanisms of soil water and vapour transport in the desert vadose zone of the extremely arid region of northern China

    Science.gov (United States)

    Du, Chaoyang; Yu, Jingjie; Wang, Ping; Zhang, Yichi

    2018-03-01

    The transport of water and vapour in the desert vadose zone plays a critical role in the overall water and energy balances of near-surface environments in arid regions. However, field measurements in extremely dry environments face many difficulties and challenges, so few studies have examined water and vapour transport processes in the desert vadose zone. The main objective of this study is to analyse the mechanisms of soil water and vapour transport in the desert vadose zone (depth of ∼350 cm) by using measured and modelled data in an extremely arid environment. The field experiments are implemented in an area of the Gobi desert in northwestern China to measure the soil properties, daily soil moisture and temperature, daily water-table depth and temperature, and daily meteorological records from DOYs (Days of Year) 114-212 in 2014 (growing season). The Hydrus-1D model, which simulates the coupled transport of water, vapour and heat in the vadose zone, is employed to simulate the layered soil moisture and temperature regimes and analyse the transport processes of soil water and vapour. The measured results show that the soil water and temperatures near the land surface have visible daily fluctuations across the entire soil profile. Thermal vapour movement is the most important component of the total water flux and the soil temperature gradient is the major driving factor that affects vapour transport in the desert vadose zone. The most active water and heat exchange occurs in the upper soil layer (depths of 0-25 cm). The matric potential change from the precipitation mainly re-draws the spatio-temporal distribution of the isothermal liquid water in the soil near the land surface. The matric potential has little effect on the isothermal vapour and thermal liquid water flux. These findings offer new insights into the liquid water and vapour movement processes in the extremely arid environment.

  9. Optimizing cooling systems in Egyptian arid urbans

    International Nuclear Information System (INIS)

    Medhat, Ahmed A.; Khalil, Essam E.

    2006-01-01

    Present study is devoted to climatic and site oriented investigations that were carried out in a new rural development in the Upper-Egypt. Bioclimatic classifications considered Upper Egypt region, near Sudan border, as a Hot and Dry climatic region. [1]. that is affected by solar heat intensities that can reach 900 W/m2 for a period ranged from 5-to-7 hours per day with the presence of study storms. Cooling season extends up to eight months per year having Upper-day-bulb temperature ranged from 400 degree centigrade - to - 470 degree centigrade while Lower-dry-bulb-temperature ranged from 280 degree centigrade - to - 320 degree centigrade with the relative humidity ranged from 10%-to-37% RH. [2]. Site surveys and field experimental and analyses of the commonly used cooling systems were investigated, evaluated and optimized for optimum indoor comfort conditions at efficient energy efficiency. [3]. Extensive analyses were performed based on Psychrometric formulae to evaluate the impact of energy consumptions related to different cooling systems such as direct expansion, chilled water, and evaporative systems. the present study enables the critical investigations of the influence of arid outdoor conditions and the required indoor thermal parameters on the energy efficiencies of HVAC-system. This work; focuses on the suggestion of suitable system that should be implemented by local energy codes in these arid urban.(Author)

  10. Evaluating impacts of climate change on future water scarcity in an intensively managed semi-arid region using a coupled model of biophysical processes and water rights

    Science.gov (United States)

    Han, B.; Flores, A. N.; Benner, S. G.

    2017-12-01

    In semiarid and arid regions where water supply is intensively managed, future water scarcity is a product of complex interactions between climate change and human activities. Evaluating future water scarcity under alternative scenarios of climate change, therefore, necessitates modeling approaches that explicitly represent the coupled biophysical and social processes responsible for the redistribution of water in these regions. At regional scales a particular challenge lies in adequately capturing not only the central tendencies of change in projections of climate change, but also the associated plausible range of variability in those projections. This study develops a framework that combines a stochastic weather generator, historical climate observations, and statistically downscaled General Circulation Model (GCM) projections. The method generates a large ensemble of daily climate realizations, avoiding deficiencies of using a few or mean values of individual GCM realizations. Three climate change scenario groups reflecting the historical, RCP4.5, and RCP8.5 future projections are developed. Importantly, the model explicitly captures the spatiotemporally varying irrigation activities as constrained by local water rights in a rapidly growing, semi-arid human-environment system in southwest Idaho. We use this modeling framework to project water use and scarcity patterns under the three future climate change scenarios. The model is built using the Envision alternative futures modeling framework. Climate projections for the region show future increases in both precipitation and temperature, especially under the RCP8.5 scenario. The increase of temperature has a direct influence on the increase of the irrigation water use and water scarcity, while the influence of increased precipitation on water use is less clear. The predicted changes are potentially useful in identifying areas in the watershed particularly sensitive to water scarcity, the relative importance of

  11. Seasonal variations in plant water status of four desert halophytes from semi-arid region of Karachi

    International Nuclear Information System (INIS)

    Aziz, I.; Gul, B.; Gulzar, S.; Khan, A

    2011-01-01

    Halophytes in arid and semi arid zones of the world are often subjected to extremely variable drought, salinity and temperature. These fluctuations may bring about changes in their osmoregulation and gas exchange responses besides other physiological and biochemical processes. The purpose of this study was to detect temporal changes in plant water status and osmotic adjustment in four desert halophytes viz., Suaeda fruticosa, Heliotropium curassavicum, Haloxylon stocksii and Atriplex stocksii from an inland community at Karachi University Campus. During the dry period (November to January) water and osmotic potentials of all test species increased with higher values in A. stocksii (salt secretor) than those of S. fruticosa and H. stocksii (salt includer) and H. curassavicum (salt excluder). Proline increased substantially and was highest in H. curassavicum followed by A. stocksii in comparison to the two salt includers. The lowering of osmotic potential corresponded to an increase in Na and Cl, lower stomatal conductance and chlorophyll content indicating reduced gas exchange during the dry period. The increase in proline may have little role in osmoreglation but could contribute in scavenging reactive oxygen species. (author)

  12. Understanding Critical Socio-political and Hydro-climatic drivers behind Water Management and Increasing Dengue Disease Burden in Arid Regions of Mexico

    Science.gov (United States)

    Akanda, A. S.; Johnson, K.; Frost, M.; Serman, E. A.

    2016-12-01

    Dengue is a significant public health problem in Mexico, with distribution of dengue throughout the country. Mexico is characterized by a number of attributes likely to contribute to the spread of dengue, including population growth, poor water management, urbanization, significant seasonal migration, and concentrated poverty. Understanding the socio-political and hydro-climatic drivers behind the increasing dengue disease burden in the central arid regions of Mexico is a vital component for modeling the distribution and spread of Aedes aegypti vector borne infections such as Dengue and Zika as more parts of the Americas is affected. Here, we focus on the critical socio-economic and environmental drivers behind water management, urbanization, and population migration in the arid Oaxaca region, situated in the rain shadow of the Sierra Madre Mountains at an altitude of 5000 feet. In contrast to the Pacific Coastal region which hosts climactic conditions conducive to the survival of Aedes aegypti mosquitoes with a moist tropical environment, Oaxaca is arid and exists in a constant state of water insecurity. Within Oaxaca City, water is trucked in and stored in large roof tanks; many of which are failing, allowing for leaks or mosquito infestation. Alternate sources range from existing cisterns, sophisticated collection systems, to open-air rock pits. Few resources exist to improve water security, particularly in poor neighborhoods creating a disincentive to invite surveillance for disease or to move to safer and improved water systems. Meanwhile, the region has experienced significant socio-political and demographic shift including migration, economic reorganization and urbanization over the last decade. The rise in dengue incidence during the dry season suggests human intervention (through migration, water management, sanitation, cultural practices) as a potentially important predictive factor. In this study, we analyze associations of regional hydroclimatic

  13. A study to explore the use of orbital remote sensing to determine native arid plant distribution. [Arizona Regional Ecological Test Site

    Science.gov (United States)

    Mcginnies, W. G. (Principal Investigator); Lepley, L. K.; Haase, E. F.; Conn, J. S.; Musick, H. B.; Foster, K. E.

    1974-01-01

    The author has identified the following significant results. It is possible to determine, from ERTS imagery, native arid plant distribution. Using techniques of multispectral masking and extensive fieldwork, three native vegetation communities were defined and mapped in the Avra Valley study area. A map was made of the Yuma area with the aid of ground truth correlations between areas of desert pavement visible on ERTS images and unique vegetation types. With the exception of the Yuma soil-vegetation correlation phenomena, only very gross differentiations of desert vegetation communities can be made from ERTS data. Vegetation communities with obvious vegetation density differences such as saguaro-paloverde, creosote bush, and riparian vegetation can be separated on the Avra Valley imagery while more similar communities such as creosote bush and saltbush could not be differentiated. It is suggested that large differences in vegetation density are needed before the signatures of two different vegetation types can be differentiated on ERTS imagery. This is due to the relatively insignificant contribution of vegetation to the total radiometric signature of a given desert scene. Where more detailed information concerning the vegetation of arid regions is required, large scale imagery is appropriate.

  14. Cost/benefit analysis of biomass energy supply options for rural smallholders in the semi-arid eastern part of Shinyanga Region in Tanzania

    Energy Technology Data Exchange (ETDEWEB)

    Wiskerke, W.T.; Dornburg, V.; Faaij, A.P.C. [Department of Science, Technology and Society, Utrecht University, Heidelberglaan 2, 3584 CS, Utrecht (Netherlands); Rubanza, C.D.K. [Tanzania Forestry Research Institute (TAFORI)/National Forest Resource Management and Agroforestry Centre (NACRAF), P.O. Box 1257, Shinyanga (Tanzania); Malimbwi, R.E. [Faculty of Forestry and Natural Resources, Sokoine University, P.O. Box 3010, Morogoro (Tanzania)

    2010-01-15

    This study analyzes the economic feasibility of sustainable smallholder bio-energy production under semi-arid conditions. The eastern part of Shinyanga region in Tanzania was chosen as a case study area. Three different sustainable biomass energy supply systems were compared by means of cost/benefit analysis: a small-scale forestation project for carbon sequestration, a short rotation woodlot and a Jatropha plantation, thereby using the produced Jatropha oil as a substitute for fuelwood or diesel. Rotational woodlots are most profitable with a Net Present Value of up to US${sub 2007} 1165/ha, a return on labour of up to US${sub 2007} 6.69/man-day and a fuelwood production cost of US${sub 2007} 0.53/GJ, compared to a local market price of US${sub 2007} 1.95/GJ. With a production cost of US${sub 2007} 19.60/GJ, Jatropha oil is too expensive to be used as an alternative for fuelwood. Instead it can be utilized economically as a diesel substitute, at an observed diesel cost of US${sub 2007} 1.49/l. The mean annual biomass increment (MAI) in semi-arid East Shinyanga is too low to collect sufficient benefits from trading forestation carbon credits under the Clean Development Mechanism (CDM) to cover the costs of forestation and forest management. (author)

  15. Foliar δ13C Showed No Altitudinal Trend in an Arid Region and Atmospheric Pressure Exerted a Negative Effect on Plant δ13C

    Directory of Open Access Journals (Sweden)

    Zixun Chen

    2017-07-01

    Full Text Available Previous studies have suggested foliar δ13C generally increases with altitude. However, some observations reported no changes or even decreased trends in foliar δ13C. We noted that all the studies in which δ13C increased with elevation were conducted in the human regions, whereas those investigations in which δ13C did not vary or decreased were conducted in areas with water stress. Thus, we proposed that the pattern of increasing δ13C with elevation is not a general one, and that δ13C may remain unchanged or decrease in plants grown in arid environments. To test the hypothesis, we sampled plants along altitude gradients on the shady and sunny slopes of Mount Tianshan characterized by arid and semiarid climates. The measurements of foliar δ13C showed no altitudinal trends for the plants grown on either of the slopes. Therefore, this study supported our hypothesis. In addition, the present study addressed the effect of atmospheric pressure on plant δ13C by accounting for the effects of temperature and precipitation on δ13C. This study found that the residual foliar δ13C increased with increasing altitude, suggesting that atmospheric pressure played a negative role in foliar δ13C.

  16. Testing grain-surface chemistry in massive hot-core regions

    Science.gov (United States)

    Bisschop, S. E.; Jørgensen, J. K.; van Dishoeck, E. F.; de Wachter, E. B. M.

    2007-04-01

    Aims:We study the chemical origin of a set of complex organic molecules thought to be produced by grain surface chemistry in high mass young stellar objects (YSOs). Methods: A partial submillimeter line-survey was performed toward 7 high-mass YSOs aimed at detecting H2CO, CH3OH, CH2CO, CH3CHO, C2H5OH, HCOOH, HNCO and NH2CHO. In addition, lines of CH3CN, C2H5CN, CH3CCH, HCOOCH3, and CH3OCH3 were observed. Rotation temperatures and beam-averaged column densities are determined. To correct for beam dilution and determine abundances for hot gas, the radius and H2 column densities of gas at temperatures >100 K are computed using 850 μm dust continuum data and source luminosity. Results: Based on their rotation diagrams, molecules can be classified as either cold (100 K). This implies that complex organics are present in at least two distinct regions. Furthermore, the abundances of the hot oxygen-bearing species are correlated, as are those of HNCO and NH2CHO. This is suggestive of chemical relationships within, but not between, those two groups of molecules. Conclusions: .The most likely explanation for the observed correlations of the various hot molecules is that they are "first generation" species that originate from solid-state chemistry. This includes H2CO, CH3OH, C2H5OH, HCOOCH3, CH3OCH3, HNCO, NH2CHO, and possibly CH3CN, and C2H5CN. The correlations between sources implies very similar conditions during their formation or very similar doses of energetic processing. Cold species such as CH2CO, CH3CHO, and HCOOH, some of which are seen as ices along the same lines of sight, are probably formed in the solid state as well, but appear to be destroyed at higher temperatures. A low level of non-thermal desorption by cosmic rays can explain their low rotation temperatures and relatively low abundances in the gas phase compared to the solid state. The CH3CCH abundances can be fully explained by low temperature gas phase chemistry. No cold N-containing molecules are found

  17. Explanation of asymmetric dynamics of human water consumption in arid regions: prospect theory versus expected utility theory

    Science.gov (United States)

    Tian, F.; Lu, Y.

    2017-12-01

    Based on socioeconomic and hydrological data in three arid inland basins and error analysis, the dynamics of human water consumption (HWC) are analyzed to be asymmetric, i.e., HWC increase rapidly in wet periods while maintain or decrease slightly in dry periods. Besides the qualitative analysis that in wet periods great water availability inspires HWC to grow fast but the now expanded economy is managed to sustain by over-exploitation in dry periods, two quantitative models are established and tested, based on expected utility theory (EUT) and prospect theory (PT) respectively. EUT states that humans make decisions based on the total expected utility, namely the sum of utility function multiplied by probability of each result, while PT states that the utility function is defined over gains and losses separately, and probability should be replaced by probability weighting function.

  18. Comparison of Modeling and Simulation Results Management Microclimate of the Greenhouse by Fuzzy Logic Between a Wetland and Arid Region

    Directory of Open Access Journals (Sweden)

    Didi Faouzi

    2016-05-01

    Full Text Available Currently the climate computer offers many benefits and solves problems related to the regulation, monitoring and controls. Greenhouse growers remain vigilant and attentive, facing this technological development. They ensure competitiveness and optimize their investments / production cost which continues to grow. The application of artificial intelligence in the industry known for considerable growth, which is not the case in the field of agricultural greenhouses, where enforcement remains timid. It is from this fact, we undertake research work in this area and conduct a simulation based on meteorological data through MATLAB Simulink to finally analyze the thermal behavior -greenhouse microclimate energy. In this paper, we present comparison of modelling and simulation management of the greenhouse microclimate by fuzzy logic between a wetland (Dar El Beida Algeria and the other arid (Biskra Algeria.

  19. Passive Design Strategies to Enhance Natural Ventilation in Buildings "Election of Passive Design Strategies to Achieve Natural Ventilation in Iraqi Urban Environment with Hot Arid Climate"

    Directory of Open Access Journals (Sweden)

    Ghada M.Ismael Abdul Razzaq Kamoona

    2016-06-01

    Full Text Available the natural ventilation in buildings is one of effective strategies for achieving energy efficiency in buildings by employing methods and ways of passive design, as well as its efficiency in providing high ranges of thermal comfort for occupants in buildings and raises their productivity. Because the concept of natural ventilation for many people confined to achieve through the windows and openings only, become necessary to provide this research to demonstrate the various passive design strategies for natural ventilation. Then, research problem: Insufficient knowledge about the importance and mechanism of the application of passive design strategies for natural ventilation in buildings. The research objective is: Analysis of passive design strategies to achieve natural ventilation in buildings, for the purpose of the proper selection of them to Iraqi urban environment. Accordingly, the research included two parts: First, the theoretical part, which dealt with the conceptual framework of natural ventilation and deriving the most important aspects in it, in order to adopted as a base for the practical part of the research. Second: the practical part, which analyzed examples of buildings projects that employed various design strategies for natural ventilation, according to the theoretical framework that has been drawn. The main conclusion is, Necessity to adopt various passive design strategies for natural ventilation in Iraqi urban environment with hot dry climate, as they have a significant impact in reducing the energy consumption for the purposes of ventilation and cooling, as well as for its efficiency in improving air quality in indoor environments of buildings.

  20. Understanding water deficit stress-induced changes in the basic metabolism of higher plants - biotechnologically and sustainably improving agriculture and the ecoenvironment in arid regions of the globe.

    Science.gov (United States)

    Shao, Hong-Bo; Chu, Li-Ye; Jaleel, C Abdul; Manivannan, P; Panneerselvam, R; Shao, Ming-An

    2009-01-01

    Water is vital for plant growth, development and productivity. Permanent or temporary water deficit stress limits the growth and distribution of natural and artificial vegetation and the performance of cultivated plants (crops) more than any other environmental factor. Productive and sustainable agriculture necessitates growing plants (crops) in arid and semiarid regions with less input of precious resources such as fresh water. For a better understanding and rapid improvement of soil-water stress tolerance in these regions, especially in the water-wind eroded crossing region, it is very important to link physiological and biochemical studies to molecular work in genetically tractable model plants and important native plants, and further extending them to practical ecological restoration and efficient crop production. Although basic studies and practices aimed at improving soil water stress resistance and plant water use efficiency have been carried out for many years, the mechanisms involved at different scales are still not clear. Further understanding and manipulating soil-plant water relationships and soil-water stress tolerance at the scales of ecology, physiology and molecular biology can significantly improve plant productivity and environmental quality. Currently, post-genomics and metabolomics are very important in exploring anti-drought gene resources in various life forms, but modern agriculturally sustainable development must be combined with plant physiological measures in the field, on the basis of which post-genomics and metabolomics have further practical prospects. In this review, we discuss physiological and molecular insights and effects in basic plant metabolism, drought tolerance strategies under drought conditions in higher plants for sustainable agriculture and ecoenvironments in arid and semiarid areas of the world. We conclude that biological measures are the bases for the solutions to the issues relating to the different types of

  1. Pandemic influenza A (H1N1 2009: epidemiological analysis of cases in a tropical/semi-arid region of Brazil

    Directory of Open Access Journals (Sweden)

    Roberto da Justa Pires Neto

    2013-04-01

    Full Text Available Introduction The year 2009 marked the beginning of a pandemic caused by a new variant of influenza A (H1N1. After spreading through North America, the pandemic influenza virus (H1N1 2009 spread rapidly throughout the world. The aim of this study was to describe the clinical and epidemiological characteristics of cases of pandemic influenza in a tropical/semi-arid region of Brazil. Methods A retrospective study analyzed all suspected cases of pandemic influenza (H1N1 2009 reported in the Ceará State through the National Information System for Notifiable Diseases during the pandemic period between 28 April, 2009 and November 25, 2010. Results A total of 616 suspected cases were notified, 58 (9.4% in the containment phase and 558 (90.6% in the mitigation phase. Most cases were of affected young people resident in the City of Fortaleza, the largest urban center in the State of Ceará. The most frequent symptoms presented by the cases with confirmed infection were fever, cough, myalgia, arthralgia, and nasal congestion. Mortality rate was 0.0009/1,000 inhabitants and lethality was 5.6%. Deaths were observed only in the mitigation phase. Mortality rates were similar for both sexes but were higher in the age group under 5 years. Conclusions The study suggests that the influenza A (H1N1 pandemic in this tropical/semi-arid region had a lower magnitude when compared to states in the Southern and Southeastern regions of Brazil.

  2. [Effect of tillage patterns on the structure of weed communities in oat fields in the cold and arid region of North China].

    Science.gov (United States)

    Zhang, Li; Zhang, Li; Wu, Dong-Xia; Zhang, Jun-Jun

    2014-06-01

    In order to clarify the effects of tillage patterns on farmland weed community structure and crop production characteristics, based on 10 years location experiment with no-tillage, subsoiling and conventional tillage in the cold and arid region of North China, and supplementary experiment of plowing after 10 years no-tillage and subsoiling, oat was planted in 2 soils under different tillage patterns, and field weed total density, dominant weed types, weed diversity index, field weed biomass and oats yield were measured. The results showed that the regional weed community was dominated by foxtail weed (Setaira viridis); the weed density under long-term no-tillage was 2.20-5.14 times of tillage at different growing stages of oat, but there were no significant differences between conditional tillage and plowing after long-term no-tillage and subsoiling. Field weed Shannon diversity indices were 0.429 and 0.531, respectively, for sandy chestnut soil and loamy meadow soil under no-tillage conditions, and field weed biomass values were 1.35 and 2.26 times of plowing treatment, while the oat biomass values were only 2807.4 kg x hm(-2) and 4053.9 kg x hm(-2), decreased by 22.3% and 46.2%, respectively. The results showed that the weed community characteristics were affected by both tillage patterns and soil types. Long-term no-tillage farmland in the cold and arid region of North China could promote the natural evolution of plant communities by keeping more perennial weeds, and the plowing pattern lowered the annual weed density, eliminated perennial weeds with shallow roots, and stimulated perennial weeds with deep roots.

  3. Murine leukemia virus vector integration favors promoter regions and regional hot spots in a human T-cell line

    International Nuclear Information System (INIS)

    Tsukahara, Tomonori; Agawa, Hideyuki; Matsumoto, Sayori; Matsuda, Mizuho; Ueno, Shuichi; Yamashita, Yuki; Yamada, Koichiro; Tanaka, Nobuyuki; Kojima, Katsuhiko; Takeshita, Toshikazu

    2006-01-01

    Genomic analysis of integration will be important in evaluating the safety of human gene therapy with retroviral vectors. Here, we investigated MLV vector integration sites in human T-cells, since they are amenable to gene transfer studies, and have been used therapeutically in clinical trials. We mapped 340 MLV vector integration sites in the infected human T-cell clones we established. The data showed that MLV preferred integration near the transcription start sites (±5 kb), near CpG islands (±1 kb), and within the first intron of RefSeq genes. We also identified MLV integration hot spots that contained three or more integrations within a 100 kb region. RT-PCR revealed that mRNA-levels of T-cell clones that contained MLV integrations near transcription start sites or introns were dysregulated compared to the uninfected cells. These studies help define the profile of MLV integration in T-cells and the risks associated with MLV-based gene therapy

  4. Identifying Hot Spots of Critical Forage Supply in Dryland Nomadic Pastoralist Areas: A Case Study for the Afar Region, Ethiopia

    NARCIS (Netherlands)

    Sonneveld, B.G.J.S.; Keyzer, M.A.; van Wesenbeeck, C.F.A.; Georgis, Kidane; Beyene, Fekadu; Urbano, Ferdinando; Meroni, Michele; Leo, Olivier; Yimer, Merkebu; Abdullatif, Mohammed

    2017-01-01

    This study develops a methodology to identify hot spots of critical forage supply in nomadic pastoralist areas, using the Afar Region, Ethiopia, as a special case. It addresses two main problems. First, it makes a spatially explicit assessment of fodder supply and demand extracted from a data poor

  5. The photovoltaic solar technology in a semi-arid Piaui region: case study; A tecnologia solar fotovoltaica no semi-arido piauiense: estudo de caso

    Energy Technology Data Exchange (ETDEWEB)

    Moraes, Albemerc Moura de; Trigoso, Federico B. Morante [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil). Centro de Engenharia, Modelagem e Ciencias Sociais Aplicadas. Programa de Pos Graduacao em Energia

    2008-07-01

    The following work has as objective to present some results of a research of field carried through in the Piaui semi-arid region that it aimed at to verify the use of the photovoltaic solar technology. For this six questionnaires in three rural communities of three municipal territories of the State in the valley of the river Caninde had been applied. It was verified that due to lack of maintenance of these systems good part of them left to still function in the first years of its installation. Although this almost all the interviewed ones had revealed signal of approval to the electric energy proceeding from these systems for the community use, however they had questioned the lack of maintenance of these and had revealed interested in possessing access in its residences of this so important good is useful, the electricity. (author)

  6. Occurrence and identification of the etiologic agents of plant diseases in cactus (Opuntia ficus-indica Mill. in the semi-arid region of Paraiba

    Directory of Open Access Journals (Sweden)

    Anne Evelyne Franco de Souza

    2010-01-01

    Full Text Available Cactus forage (Opuntia ficus-indica Mill., intensely cultivated in dry regions of northeast Brazil, although well adapted to the harsh semi-arid climate is affected by major problems such as pests and diseases, responsible for significant losses in production. This study aimed to investigate the occurrence and diversity of the etiologic agents of diseases of cactus cultivated in 38 municipalities in the semi-arid region of Paraiba. The analyses were conducted and processed at the Laboratory of Phytopathology of the Centro de Ciências Agrárias da Universidade Federal da Paraíba, in Areia - PB. Starting from sick cladodes isolations, multiplications and identifications of the found microorganisms were made. The identification of the microorganisms was achieved through observations of the macro and micromorphological characteristics of the cultures and tests of Gram and pathogenicity. Great incidence and diversity of microorganisms was verified in the cacti researched, but the highest occurrence was mainly that of fungus. The fungi of widest occurrence were: Scytallidium lignicola, Alternate tenuis, Macrophomina phaseolina, Cladosporium cladosporides, Lasiodiplodia theobromae, Fusarium oxysporum f. sp. opuntiarum, Curvularia lunata, Aspergillus niger, Nigrospora sphaerica, Colletotrichum gloeosporioides, Exserohilum turcicum, Pestalotia pitospora, Rhizopus stolonifer, Rhizoctonia solani and Sphaceloma protearum. A bacterium was also detected that was suspected to belong to the Erwinia sp. strain. Satisfaction of the Postulates of Koch proved the infectious nature of the detected microorganisms. High occurrence of the fungus S. lignicola, an agent of scale rot disease in 100% of the places researched, was observed. This fact is of great concern, since the progression of the disease can cause significant losses in production.

  7. Trends and variations of pH and hardness in a typical semi-arid river in a monsoon climate region during 1985-2009.

    Science.gov (United States)

    Hao, Shaonan; Li, Xuyong; Jiang, Yan; Zhao, Hongtao; Yang, Lei

    2016-09-01

    The rapid growth of urbanization and industrialization, along with dramatic climate change, has strongly influenced hydrochemical characteristics in recent decades in China and thus could cause the variation of pH and general total hardness of a river. To explore such variations and their potential influencing factors in a river of the monsoon climate region, we analyzed a long-term monitoring dataset of pH, SO4 (2-), NOx, general total hardness (GH), Mg(2+), Ca(2+), and Cl(-) in surface water and groundwater in the Luan River basin from 1985 to 2009. The nonparametric Seasonal Kendall trend test was used to test the long-term trends of pH and GH. Relationship between the affecting factors, pH and GH were discussed. Results showed that pH showed a decreasing trend and that GH had an increasing trend in the long-term. Seasonal variation of pH and GH was mainly due to the typical monsoon climate. Results of correlation analysis showed that the unit area usage amounts of chemical fertilizer, NO3 (-), and SO4 (2-) were negatively correlated with pH in groundwater. In addition, mining activity affected GH spatial variation. Acid deposition, drought, and increasing the use of chemical fertilizers would contribute to the acidification trend, and mining activities would affect the spatial variation of GH. Variations of precipitation and runoff in semi-arid monsoon climate areas had significant influences on the pH and GH. Our findings implied that human activities played a critical role in river acidification in the semi-arid monsoon climate region of northern China.

  8. Modeling the Land Use/Cover Change in an Arid Region Oasis City Constrained by Water Resource and Environmental Policy Change using Cellular Automata Model

    Science.gov (United States)

    Hu, X.; Li, X.; Lu, L.

    2017-12-01

    Land use/cover change (LUCC) is an important subject in the research of global environmental change and sustainable development, while spatial simulation on land use/cover change is one of the key content of LUCC and is also difficult due to the complexity of the system. The cellular automata (CA) model had an irreplaceable role in simulating of land use/cover change process due to the powerful spatial computing power. However, the majority of current CA land use/cover models were binary-state model that could not provide more general information about the overall spatial pattern of land use/cover change. Here, a multi-state logistic-regression-based Markov cellular automata (MLRMCA) model and a multi-state artificial-neural-network-based Markov cellular automata (MANNMCA) model were developed and were used to simulate complex land use/cover evolutionary process in an arid region oasis city constrained by water resource and environmental policy change, the Zhangye city during the period of 1990-2010. The results indicated that the MANNMCA model was superior to MLRMCA model in simulated accuracy. These indicated that by combining the artificial neural network with CA could more effectively capture the complex relationships between the land use/cover change and a set of spatial variables. Although the MLRMCA model were also some advantages, the MANNMCA model was more appropriate for simulating complex land use/cover dynamics. The two proposed models were effective and reliable, and could reflect the spatial evolution of regional land use/cover changes. These have also potential implications for the impact assessment of water resources, ecological restoration, and the sustainable urban development in arid areas.

  9. Study on simulation methods of atrium building cooling load in hot and humid regions

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Yiqun; Li, Yuming; Huang, Zhizhong [Institute of Building Performance and Technology, Sino-German College of Applied Sciences, Tongji University, 1239 Siping Road, Shanghai 200092 (China); Wu, Gang [Weldtech Technology (Shanghai) Co. Ltd. (China)

    2010-10-15

    In recent years, highly glazed atria are popular because of their architectural aesthetics and advantage of introducing daylight into inside. However, cooling load estimation of such atrium buildings is difficult due to complex thermal phenomena that occur in the atrium space. The study aims to find out a simplified method of estimating cooling loads through simulations for various types of atria in hot and humid regions. Atrium buildings are divided into different types. For every type of atrium buildings, both CFD and energy models are developed. A standard method versus the simplified one is proposed to simulate cooling load of atria in EnergyPlus based on different room air temperature patterns as a result from CFD simulation. It incorporates CFD results as input into non-dimensional height room air models in EnergyPlus, and the simulation results are defined as a baseline model in order to compare with the results from the simplified method for every category of atrium buildings. In order to further validate the simplified method an actual atrium office building is tested on site in a typical summer day and measured results are compared with simulation results using the simplified methods. Finally, appropriate methods of simulating different types of atrium buildings are proposed. (author)

  10. Isovector giant dipole resonance in hot rotating light nuclei in the calcium region

    International Nuclear Information System (INIS)

    Shanmugam, G.; Thiagasundaram, M.

    1989-01-01

    The isovector giant dipole resonances in hot rotating light nuclei in the calcium region are studied using a rotating anisotropic harmonic oscillator potential and a separable dipole-dipole residual interaction. The influence of temperature on the isovector giant dipole resonance is assumed to occur through the change of deformation of the average field only. Calculations are performed for the three nuclei /sup 40,42/Ca and /sup 46/Ti which have spherical, oblate, and prolate ground states, respectively, to see how their shape transitions at higher excited states affect the isovector giant resonance frequencies built on them. It is seen that, while the width fluctuations present at T = 0 vanish at T = 0.5 MeV in /sup 40,42/Ca, they persist up to T = 1.5 MeV in the case of /sup 46/Ti. This behavior brings out the role of temperature on shell effects which in turn affects the isovector giant dipole resonance widths

  11. Daily global solar radiation modelling using multi-layer perceptron neural networks in semi-arid region

    Directory of Open Access Journals (Sweden)

    Mawloud GUERMOUI

    2016-07-01

    Full Text Available Accurate estimation of Daily Global Solar Radiation (DGSR has been a major goal for solar energy application. However, solar radiation measurements are not a simple task for several reasons. In the cases where data are not available, it is very common the use of computational models to estimate the missing data, which are based mainly of the search for relationships between weather variables, such as temperature, humidity, sunshine duration, etc. In this respect, the present study focuses on the development of artificial neural network (ANN model for estimation of daily global solar radiation on horizontal surface in Ghardaia city (South Algeria. In this analysis back-propagation algorithm is applied. Daily mean air temperature, relative humidity and sunshine duration was used as climatic inputs parameters, while the daily global solar radiation (DGSR was the only output of the ANN. We have evaluated Multi-Layer Perceptron (MLP models to estimate DGSR using three year of measurement (2005-2008. It was found that MLP-model based on sunshine duration and mean air temperature give accurate results in term of Mean Absolute Bias Error, Root Mean Square Error, Relative Square Error and Correlation Coefficient. The obtained values of these indicators are 0.67 MJ/m², 1.28 MJ/m², 6.12%and 98.18%, respectively which shows that MLP is highly qualified for DGSR estimation in semi-arid climates.

  12. Transport of elemental mercury in the unsaturated zone from a waste disposal site in an arid region

    Science.gov (United States)

    Walvoord, Michelle Ann; Andraski, Brian J.; Krabbenhoft, D.P.; Striegl, Robert G.

    2008-01-01

    Mercury contained in buried landfill waste may be released via upward emission to the atmosphere or downward leaching to groundwater. Data from the US Geological Survey’s Amargosa Desert Research Site (ADRS) in arid southwestern Nevada reveal another potential pathway of Hg release: long-distance (102 m) lateral migration of elemental Hg (Hg0) through the unsaturated zone. Gas collected from multiple depths from two instrumented boreholes that sample the entire 110-m unsaturated zone thickness and are located 100 and 160 m away from the closest waste burial trench exhibit gaseous Hg concentrations of up to 33 and 11 ng m−3, respectively. The vertical distribution of gaseous Hg in the borehole closest to the disposal site shows distinct subsurface peaks in concentration at depths of 1.5 and 24 m that cannot be explained by radial diffusive transport through a heterogeneous layered unsaturated zone. The inability of current models to explain gaseous Hg distribution at the ADRS highlights the need to advance the understanding of gas-phase contaminant transport in unsaturated zones to attain a comprehensive model of landfill Hg release.

  13. Spatial and temporal distribution of free-living protozoa in aquatic environments of a Brazilian semi-arid region

    Directory of Open Access Journals (Sweden)

    Maria Luisa Quinino de Medeiros

    2013-08-01

    Full Text Available Free-living protozoa organisms are distributed in aquatic environments and vary widely in both qualitative and quantitative terms. The unique ecological functions they exhibit in their habitats help to maintain the dynamic balance of these environments. Despite their wide range and abundance, studies on geographical distribution and ecology, when compared to other groups, are still scarce. This study aimed to identify and record the occurrence of free-living protozoa at three points in Piancó-Piranhas-Açu basin, in a semi-arid area of Rio Grande do Norte (RN state, and to relate the occurrence of taxa with variations in chlorophyll a, pH and temperature in the environments. Samples were collected in the Armando Ribeiro Gonçalves Dam, from two lentic environments upstream and a lotic ecosystem downstream. Sixty-five taxa of free-living protozoa were found. The Student's t-test showed significant inter-variable differences (p <0.05. Similar protozoan species were recorded under different degrees of trophic status according to chlorophyll a concentrations, suggesting the organisms identified are not ideal for indicating trophic level. We hypothesize that food availability, the influence of lentic and lotic systems and the presence of aquatic macrophytes influenced protozoan dynamics during the study period.

  14. Succession of carrion fauna in the arid region of San Juan Province, Argentina and its forensic relevance.

    Science.gov (United States)

    Aballay, F H; Murua, A F; Acosta, J C; Centeno, N D

    2012-02-01

    The succession of carrion fauna and the decomposition stages were studied in the arid environment of San Juan Province, Argentina (31°32'34.7″ S; 68°34'39.4″ W). Two pig carcasses (Sus scrofa) were placed in wire mesh cages, 100 m apart from each other. Each carcass was surrounded by pitfall traps, and a modified Malaise trap was placed above. Daily samplings were carried out to collect the insects present in the carcasses and the traps, and body and environmental temperature were measured. The main colonizer species was Chrysomya albiceps (Wiedemann) and its larvae were dominant over other Diptera. The first adult blowflies emerged at 8.9 days. The time to reach the remains stage was 8 days shorter than for other South American sites. We recorded the early arrival of adult Dermestes maculates De Geer and Dermestes ater De Geer 2 days after the beginning of the assay, and larvae of these species were recorded 4 days after. We determined a 1.5-day error in the postmortem interval estimation using the temperatures measured in the assay and those recorded by the nearest meteorological station.

  15. Spatial and temporal dynamics of deep percolation, lag time and recharge in an irrigated semi-arid region

    Science.gov (United States)

    Nazarieh, F.; Ansari, H.; Ziaei, A. N.; Izady, A.; Davari, K.; Brunner, P.

    2018-05-01

    The time required for deep percolating water to reach the water table can be considerable in areas with a thick vadose zone. Sustainable groundwater management, therefore, has to consider the spatial and temporal dynamics of groundwater recharge. The key parameters that control the lag time have been widely examined in soil physics using small-scale lysimeters and modeling studies. However, only a small number of studies have analyzed how deep-percolation rates affect groundwater recharge dynamics over large spatial scales. This study examined how the parameters influencing lag time affect groundwater recharge in a semi-arid catchment under irrigation (in northeastern Iran) using a numerical modeling approach. Flow simulations were performed by the MODFLOW-NWT code with the Vadose-Zone Flow (UZF) Package. Calibration of the groundwater model was based on data from 48 observation wells. Flow simulations showed that lag times vary from 1 to more than 100 months. A sensitivity analysis demonstrated that during drought conditions, the lag time was highly sensitive to the rate of deep percolation. The study illustrated two critical points: (1) the importance of providing estimates of the lag time as a basis for sustainable groundwater management, and (2) lag time not only depends on factors such as soil hydraulic conductivity or vadose zone depth but also depends on the deep-percolation rates and the antecedent soil-moisture condition. Therefore, estimates of the lag time have to be associated with specific percolation rates, in addition to depth to groundwater and soil properties.

  16. Magnetized Converging Flows toward the Hot Core in the Intermediate/High-mass Star-forming Region NGC 6334 V

    Energy Technology Data Exchange (ETDEWEB)

    Juárez, Carmen; Girart, Josep M. [Institut de Ciències de l’Espai, (CSIC-IEEC), Campus UAB, Carrer de Can Magrans, S/N, E-08193 Cerdanyola del Vallès, Catalonia (Spain); Zamora-Avilés, Manuel; Palau, Aina; Ballesteros-Paredes, Javier [Instituto de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, P.O. Box 3-72, 58090, Morelia, Michoacán (Mexico); Tang, Ya-Wen; Koch, Patrick M.; Liu, Hauyu Baobab [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei, 10617, Taiwan (China); Zhang, Qizhou [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Qiu, Keping, E-mail: juarez@ice.cat [School of Astronomy and Space Science, Nanjing University, 163 Xianlin Avenue, Nanjing 210023 (China)

    2017-07-20

    We present Submillimeter Array (SMA) observations at 345 GHz toward the intermediate/high-mass cluster-forming region NGC 6334 V. From the dust emission we spatially resolve three dense condensations, the brightest one presenting the typical chemistry of a hot core. The magnetic field (derived from the dust polarized emission) shows a bimodal converging pattern toward the hot core. The molecular emission traces two filamentary structures at two different velocities, separated by 2 km s{sup −1}, converging to the hot core and following the magnetic field distribution. We compare the velocity field and the magnetic field derived from the SMA observations with magnetohydrodynamic simulations of star-forming regions dominated by gravity. This comparison allows us to show how the gas falls in from the larger-scale extended dense core (∼0.1 pc) of NGC 6334 V toward the higher-density hot core region (∼0.02 pc) through two distinctive converging flows dragging the magnetic field, whose strength seems to have been overcome by gravity.

  17. Magnetized Converging Flows toward the Hot Core in the Intermediate/High-mass Star-forming Region NGC 6334 V

    International Nuclear Information System (INIS)

    Juárez, Carmen; Girart, Josep M.; Zamora-Avilés, Manuel; Palau, Aina; Ballesteros-Paredes, Javier; Tang, Ya-Wen; Koch, Patrick M.; Liu, Hauyu Baobab; Zhang, Qizhou; Qiu, Keping

    2017-01-01

    We present Submillimeter Array (SMA) observations at 345 GHz toward the intermediate/high-mass cluster-forming region NGC 6334 V. From the dust emission we spatially resolve three dense condensations, the brightest one presenting the typical chemistry of a hot core. The magnetic field (derived from the dust polarized emission) shows a bimodal converging pattern toward the hot core. The molecular emission traces two filamentary structures at two different velocities, separated by 2 km s −1 , converging to the hot core and following the magnetic field distribution. We compare the velocity field and the magnetic field derived from the SMA observations with magnetohydrodynamic simulations of star-forming regions dominated by gravity. This comparison allows us to show how the gas falls in from the larger-scale extended dense core (∼0.1 pc) of NGC 6334 V toward the higher-density hot core region (∼0.02 pc) through two distinctive converging flows dragging the magnetic field, whose strength seems to have been overcome by gravity.

  18. Integrating wastewater reuse in water resources management for hotels in arid coastal regions - Case Study of Sharm El Sheikh, Egypt.

    Science.gov (United States)

    Lamei, A; van der Zaag, P; Imam, E

    2009-01-01

    Hotels in arid coastal areas use mainly desalinated water (using reverse osmosis) for their domestic water supply, and treated wastewater for irrigating green areas. Private water companies supply these hotels with their potable and non-potable water needs. There is normally a contractual agreement stating a minimum amount of water that has to be supplied by the water company and that the hotel management has to pay for regardless of its actual consumption ("contracted-for water supply"). Hotels have to carefully analyse their water requirements in order to determine which percentage of the hotel's peak water demand should be used in the contract in order to reduce water costs and avoid the risk of water shortage. This paper describes a model to optimise the contracted-for irrigation water supply with the objective function to minimise total water cost to hotels. It analyses what the contracted-for irrigation water supply of a given hotel should be, based on the size of the green irrigated area on one hand and the unit prices of the different types of water on the other hand. An example from an arid coastal tourism-dominated city is presented: Sharm El Sheikh (Sharm), Egypt. This paper presents costs of wastewater treatment using waste stabilisation ponds, which is the prevailing treatment mechanism in the case study area for centralised plants, as well as aerobic/anaerobic treatment used for decentralised wastewater treatment plants in the case study area. There is only one centralised wastewater treatment plant available in the city exerting monopoly and selling treated wastewater to hotels at a much higher price than the actual cost that a hotel would bear if it treated its own wastewater. Contracting for full peak irrigation demand is the highest total cost option. Contracting for a portion of the peak irrigation demand and complementing the rest from desalination water is a cheaper option. A better option still is to complement the excess irrigation demand

  19. Photosynthetic limitation and mechanisms of photoprotection under drought and recovery of Calotropis procera, an evergreen C3 from arid regions.

    Science.gov (United States)

    Rivas, Rebeca; Frosi, Gabriella; Ramos, Diego G; Pereira, Silvia; Benko-Iseppon, Ana M; Santos, Mauro G

    2017-09-01

    Calotropis procera is a C 3 plant native from arid environmental zones. It is an evergreen, shrubby, non-woody plant with intense photosynthetic metabolism during the dry season. We measured photosynthetic parameters and leaf biochemical traits, such as gas exchange, photochemical parameters, A/C i analysis, organic solutes, and antioxidant enzymes under controlled conditions in potted plants during drought stress, and following recovery conditions to obtain a better insight in the drought stress responses of C. procera. Indeed, different processes contribute to the drought stress resilience of C. procera and to the fast recovery after rehydration. The parameters analyzed showed that C. procera has a high efficiency for energy dissipation. The photosynthetic machinery is protected by a robust antioxidant system and photoprotective mechanisms such as alternative pathways for electrons (photorespiration and day respiration). Under severe drought stress, increased stomatal limitation and decreased biochemical limitation permitted C. procera to maintain maximum rate of Rubisco carboxylation (V c,max ) and photosynthetic rate (A max ). On the other hand, limitation of stomatal or mesophyll CO 2 diffusion did not impair fast recovery, maintaining V c,max , chloroplast CO 2 concentration (C c ) and mesophyll conductance (g m ) unchanged while electron flow used for RuBP carboxylation (J c ) and A max increased. The ability to tolerate drought stress and the fast recovery of this evergreen C 3 species was also due to leaf anti-oxidative stress enzyme activity, and photosynthetic pigments. Thus, these different drought tolerance mechanisms allowed high performance of photosynthetic metabolism by drought stressed plants during the re-watering period. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  20. A tale of ENSO, PDO, and increasing aridity impacts on drought-deciduous shrubs in the Death Valley region.

    Science.gov (United States)

    Ehleringer, James R; Sandquist, Darren R

    2018-06-28

    Germination, establishment, phenology, and death among three drought-deciduous shrubs were influenced by ENSO/PDO and precipitation, based on 37 years of annual surveys. Encelia farinosa forms near monospecific stands on slopes, whereas E. frutescens and Ambrosia salsola dominate wash habitats. All shrubs exhibited phenological coherence. While germination, establishment, and mortality patterns were similar among wash species, these dynamics contrasted with E. farinosa on slopes. Germination was associated with El Niño years. Slope plant establishment was dependent on precipitation in the subsequent year, but not evidently so in wash species. Major mortality events were episodic, with Encelia mortality just as likely to occur in years with below or above average precipitation. In both Encelia species, mortality was associated with transitions to a cold PDO phase. In E. frutescens this response was more rapid, whereas in E. farinosa mortality lagged 1 year, resulting in contrasting slope-wash mortality patterns. 50% of newly established shrubs died within 5, 5, and 18 years for E. frutescens, E. farinosa, and A. salsola, respectively. The 90% mortality ages were 26 years for E. frutescens, 24 years for E. farinosa, and 51 years for A. salsola. While maximum life expectancies are unknown, estimated maximum life expectancies were 56, 66, and 86 years for E. frutescens, E. farinosa, and A. salsola, respectively. Overall, as the climate has become more arid over the past four decades, the populations in both slope and wash habitats have exhibited similar responses: reduced shrub abundances and reduced total supportable leaf areas.

  1. Fuel reprocessing plant environmental impact in the arid regions of the western United States. Annual report, October 1976--September 1977

    International Nuclear Information System (INIS)

    Seale, R.L.

    1977-01-01

    The first year of the fuel reprocessing plant environmental impact study has been completed. During this time, emphasis has been placed on the description of a reference plant and on the characterization of arid lands located sites. In addition, it was recognized early that the development of a rational methodology for comparing various siting proposals, both in terms of the extent of the facilities to be constructed at any given site and in terms of the selection of the best site among a range of alternatives, would be necessary. Indeed, this decision has already been confirmed in that its appropriateness has survived the rather severe changes in the nuclear fuel cycle policy that have occurred in the past year. Indeed, the very fact that these changes have occurred and comparable alterations in basic policy may be expected in the future, tend to emphasize the necessity for developing logical and rational methods of system evaluation which have the inherent flexibility necessary to reflect these various policy options. In carrying out the study the full scope of technical expertise available has been brought to bear on the various appropriate parts of the overall study. Coordination between these various investigators throughout this period has been open, productive, and, in some cases, spirited. The resolution of many of the questions raised in this initial phase of the study has contributed significantly to the development of the siting methodology. An assessment of the existing regulatory climate as it reflects throughout the appropriate position in the federal establishment has been completed. Identification of comparable material at the state level is certainly a more diffuse and uncertain process. Demonstration of the workability of the siting methodology is currently one of the major objectives of the next year of study. That objective should be met within the presently defined program schedule and budget

  2. Detecting and quantifying the extent of desertification and its impact in the semi-arid Sub-Saharan Africa: A case study of the Upper East Region, Ghana

    Science.gov (United States)

    Owusu, Alex B.

    The semi-arid Sub-Saharan region of Africa is in a state of permanent instability at a variety of spatio-temporal momentum. Efforts at sustaining and managing this fragile but all-important ecosystem and its processes require collecting, storing and analyzing multispatial and temporal data that are accurate and continuously updated in terms of changes (degradation), types and magnitude of change. Remote sensing techniques based on multispectral satellite-acquired data (AVHRR, Landsat TM and ETM+) have demonstrated an immense potential as a means to detect, quantify, monitor and map these changes. However, much of what satellite sensors can detect and capture, especially in the form of vegetation index (NDVI), do not tell the entire story about land degradation. This research used multispectral remote sensing data from three sensors (AVHRR, Landsat TM, and ETM+ and IKONOS) to detect and quantify the spatio-temporal land degradation (desertification) to validate the local observation and perception of desertification. The study also analyzes data on crop production in search of evidence proving or disproving degradation in the semi-arid sahel-sudan savannah transitional vegetation zone of the UER, Ghana. Multispectral satellite-acquired NDVI, from AVHRR, Landsat TM & ETM+, show that vegetation greenness is on the ascendancy, although there are pockets (localized degradation) signs of severe land degradation; field evidence suggests that the increasing NDVI is caused by vegetation succession where locally adapted horsetail grasses have been displaced by environmentally efficient, short-lived, quick maturing and dense grasses due to excessive burning, rapid population growth and inappropriate development policies. Local people's perceptions, supported by crop production data, suggest extensive land degradation. Other evidence includes food insecurity, diseases, rainfall variability and land extensification to marginal lands. Convergence of evidence suggests that

  3. Increasing salinity drastically reduces hatching success of crustaceans from depression wetlands of the semi-arid Eastern Cape Karoo region, South Africa.

    Science.gov (United States)

    Mabidi, Annah; Bird, Matthew S; Perissinotto, Renzo

    2018-04-13

    Salinity is an important factor affecting freshwater aquatic species distribution and diversity. The semi-arid Eastern Cape Karoo region of South Africa has been earmarked for shale gas development through hydraulic fracturing. The process uses large amounts of water and produces briny wastewater. When not managed properly, these wastewaters may lead to salinisation of surface freshwater bodies in the region. Therefore, the effect of salinity on the hatching success of crustacean resting eggs was examined using sediments from four depression wetlands found in the region. The sediments were exposed for 28 days to salinity levels of 0.5 g L -1 , 2.5 g L -1 , 5 g L -1 and 10 g L -1 . Control aquaria in which no salt was added were also set up. There was a significant decrease in the emerged taxa richness and abundances at salinities of 2.5 g L -1 and above. Anostraca, Notostraca and Spinicaudata hatchlings were abundant at salinities of 0.5 g L -1 and below, while Copepoda, Daphniidae (Cladocera) and Ostracoda were observed in the highest salinity, but their densities were still lower with increased salinities. Given the importance of large branchiopods in the trophic balance of depression wetlands, their loss may alter the ecological balance and function of these ecosystems.

  4. Geochemical characterization and evaluation of groundwater suitability for domestic and agricultural utility in semi-arid region of Basara, Telangana State, South India

    Science.gov (United States)

    Adimalla, Narsimha; Venkatayogi, Sudarshan

    2018-03-01

    Hydrogeochemical investigations were carried out in semi-arid region of Basara to estimate the quality of groundwater for its suitability for domestic and agricultural purposes. For this region 34 groundwater samples were collected in different locations and analyzed for various ions, viz., Na+, Ca2+, Mg2+, K+, Cl-, HCO3 -, SO4 2-, CO3 2-, HCO3 -, NO3 - and F- to assess the water chemistry with sodium absorption ratio, %Na, residual sodium carbonate, magnesium hazard. The nitrate and fluoride concentrations were above the maximum permissible limit, while calcium, sodium, potassium and chloride were found below the desirable limits in most of the groundwater samples. The Wilcox diagram illustrates that 59% of the samples belong to excellent to good category, while the US Salinity Laboratory diagram indicates medium salinity/low sodium content in 64.70% of samples. In general, the geochemistry of groundwater in Basara region is influenced by the water rock processes through percolation and dissolution of rock forming minerals, while calculated values of saturation index for Anhydrite, Aragonite, Artinite, Brucite, Calcite, Fluorite, Gypsum, Dolomite and Magnesite of the groundwater samples were less than zero, indicating under-saturation. Chadha rectangular diagram for geochemical classification and hydrochemical processes of groundwater for Basara provinces indicates 50% of Na+-Cl-, 29% of Ca2+-Mg2+-Cl- and 18% of the water samples concentrate in the category of Na+-HCO3 - type.

  5. Assessment of drought risk by using vegetation indices from remotely sensed data a perspective from hot and arid district of pakistan

    International Nuclear Information System (INIS)

    Tabassum, R.; Kahlid, A.

    2016-01-01

    The Shaheed Benazir Abad District is situated at the center of Sindh Province, which is one of the hottest and driest part of Pakistan. In the past few decades, the extreme and moderate droughts had been reported in the district with peak value -2.4 recorded using the Standardized Precipitation Index (SPI). In this study, satellite remote sensing and digital image processing techniques were used to monitor the drought conditions in the district. Multiple drought indices were calculated by using Thematic Mapper (TM) data of the Landsat satellite program, jointly managed by the U.S. Geological Survey (USGS) and the National Aeronautics and Space Administration (NASA), including Land Surface Temperature (LST), Normalized Vegetation Index (NDVI), Vegetation Condition Index (VCI) and Temperature Vegetation Index (TVX). These indices provided the agricultural drought conditions for the duration of 1992-2011. The VCI maps indicated the high drought conditions in the plain land, away from the built-up areas, while the proximity of the built-up land is under a moderate drought. However, in cultivated lands, the agriculture drought condition is not obvious due to canal irrigated cultivation. A drought in year 2011, was more severe than in the year 2000. It is an indication of climate change impacts in the region. (author)

  6. X-ray emitting hot plasma in solar active regions observed by the SphinX spectrometer

    Science.gov (United States)

    Miceli, M.; Reale, F.; Gburek, S.; Terzo, S.; Barbera, M.; Collura, A.; Sylwester, J.; Kowalinski, M.; Podgorski, P.; Gryciuk, M.

    2012-08-01

    Aims: The detection of very hot plasma in the quiescent corona is important for diagnosing heating mechanisms. The presence and the amount of such hot plasma is currently debated. The SphinX instrument on-board the CORONAS-PHOTON mission is sensitive to X-ray emission of energies well above 1 keV and provides the opportunity to detect the hot plasma component. Methods: We analysed the X-ray spectra of the solar corona collected by the SphinX spectrometer in May 2009 (when two active regions were present). We modelled the spectrum extracted from the whole Sun over a time window of 17 days in the 1.34-7 keV energy band by adopting the latest release of the APED database. Results: The SphinX broadband spectrum cannot be modelled by a single isothermal component of optically thin plasma and two components are necessary. In particular, the high statistical significance of the count rates and the accurate calibration of the spectrometer allowed us to detect a very hot component at ~7 million K with an emission measure of ~2.7 × 1044 cm-3. The X-ray emission from the hot plasma dominates the solar X-ray spectrum above 4 keV. We checked that this hot component is invariably present in both the high and low emission regimes, i.e. even excluding resolvable microflares. We also present and discuss the possibility of a non-thermal origin (which would be compatible with a weak contribution from thick-target bremsstrahlung) for this hard emission component. Conclusions: Our results support the nanoflare scenario and might confirm that a minor flaring activity is ever-present in the quiescent corona, as also inferred for the coronae of other stars.

  7. Hot-spot analysis applied to the identification of potential high and low regulating, providing and cultural ecosystem services in Vilnius Region (Lithuania)

    Science.gov (United States)

    Pereira, Paulo; Daniel, Depellegrin; Egarter-Vigl, Lukas; Cerda, Artemi; Estebaranz, Ferran; Misiune, Ieva

    2017-04-01

    Ecosystem services (ES) potential assessment is crucial for a correct territorial planning at different scales of analysis (Depellegrin et al., 2016). In urban and peri-urban areas, sprawl, grazing and unsustainable agriculture practices contributed to land degradation and de decrease of the quality and quantity of the services provided by these areas (Eldridge and Delgado-Baquerizo, 2017; Favretto et al., 2017). In order to understand the spatial pattern of these impacts, mapping ES potential is key to understand the areas that need to be restored and protected for an unsustainable use (Brevik et al., 2016; Egarter-Vigl et al., 2017; Pereira et al., 2017). Hot-spot analysis is a good method to identify clusters of areas with high and low capacity for ES capacity. This analysis is very useful to detect homogeneous areas, where ES have high or low quality. The objective of this work is to apply a hot-spot analysis to detect areas with high/low capacity for Regulating, Provision, Cultural and Total ES in Vilnius region. ES potential was carried out based on the matrix developed by Burkhard et al. (2009), which ranks ES capacity from 0= no capacity to 5=very high relevant capacity to a different land use type. The results showed that regulating, providing and cultural and total ES have a significant dispersed (low-clustered) pattern: Regulating (Z-score=-19.28, pInternational Journal of Sustainable Development and World Ecology, 23, 441-455. Egarter-Vigl, L., Depellegrin, D., Pereira, P., De Groot, D., Tappeiner, U. (2017) Mapping the ecosystem service delivery chain: Capacity, flow, and demand pertaining to aesthetic experiences in mountain landscapes, Science of the Total Environment, 574, 442-436. Eldridge, D.J., Delgado-Baquerizo, M. (2017) Continental-scale impacts of livestock grazing on ecosystem supporting and regulating services. Land Degradation and Development. DOI: 10.1002/ldr.2668 Favretto, N., Lueding, E., Stringer, L., Dougill, A.J. (2017) Valuing

  8. Seed germination, seedling traits, and seed bank of the tree Moringa peregrina (Moringaceae) in a hyper-arid environment.

    Science.gov (United States)

    Gomaa, Nasr H; Picó, F Xavier

    2011-06-01

    Water-limited hot environments are good examples of hyper-aridity. Trees are scarce in these environments but some manage to survive, such as the tree Moringa peregrina. Understanding how trees maintain viable populations in extremely arid environments may provide insight into the adaptive mechanisms by which trees cope with extremely arid weather conditions. This understanding is relevant to the current increasing aridity in several regions of the world. Seed germination experiments were conducted to assess variation in seed mass, seed germination, and seedling traits of Moringa peregrina plants and the correlations among these traits. A seed burial experiment was also designed to study the fate of M. peregrina seeds buried at two depths in the soil for two time periods. On average, seeds germinated in three days and seedling shoots grew 0.7 cm per day over three weeks. Larger seeds decreased germination time and increased seedling growth rates relative to smaller seeds. Seeds remained quiescent in the soil and germination was very high at both depths and burial times. The after-ripening time of Moringa peregrina seeds is short and seeds germinate quickly after imbibition. Plants of M. peregrina may increase in hyper-arid environments from seeds with larger mass, shorter germination times, and faster seedling growth rates. The results also illustrate the adjustment in allocation to seed biomass and correlations among seed and seedling traits that allows M. peregrina to be successful in coping with aridity in its environment.

  9. Mapping lake level changes using ICESat/GLAS satellite laser altimetry data: a case study in arid regions of central Asia

    Science.gov (United States)

    Li, JunLi; Fang, Hui; Yang, Liao

    2011-12-01

    Lakes in arid regions of Central Asia act as essential components of regional water cycles, providing sparse but valuable water resource for the fragile ecological environments and human lives. Lakes in Central Asia are sensitive to climate change and human activities, and great changes have been found since 1960s. Mapping and monitoring these inland lakes would improve our understanding of mechanism of lake dynamics and climatic impacts. ICESat/GLAS satellite laser altimetry provides an efficient tool of continuously measuring lake levels in these poorly surveyed remote areas. An automated mapping scheme of lake level changes is developed based on GLAS altimetry products, and the spatial and temporal characteristics of 9 typical lakes in Central Asia are analyzed to validate the level accuracies. The results show that ICESat/GLAS has a good performance of lake level monitoring, whose patterns of level changes are the same as those of field observation, and the max differences between GLAS and field data is 3cm. Based on the results, it is obvious that alpine lakes are increasing greatly in lake levels during 2003-2009 due to climate change, while open lakes with dams and plain endorheic lakes decrease dramatically in water levels due to human activities, which reveals the overexploitation of water resource in Central Asia.

  10. Religiousness/spirituality do not necessarily matter: Effect on risk perception and adaptive strategies in the semi-arid region of NE Brazil

    Directory of Open Access Journals (Sweden)

    Regina Célia da Silva Oliveira

    2017-07-01

    Full Text Available The impact of environmental changes is a major threat to livelihoods, especially for small farmers in semi-arid regions. Therefore, local communities undertake efforts to cope with these new environmental conditions and researchers try to understand the limits of possible adaptive strategies. Religiousness/spirituality are two important factors that can influence environmental awareness and adaptive responses to risks caused by natural phenomena. However, studies addressing the relationship between such factors are either scarce or based on anecdotal information. This article discusses the influence of religiousness/spirituality on the perception of environmental risks by farmers in a rural community in Brazil's northeast region, and their knowledge of adaptive strategies to deal with such concerns. Religiousness/spirituality can positively or negatively influence the perception of risk and knowledge of adaptive strategies when facing environmental uncertainty. We note that dimensions of religiousness/spirituality such as religious history, values/beliefs, commitment, and daily spiritual experiences influence wealth and the sharing of natural perceived risks, as well as adaptive strategies. Based on our results, we conclude that religiousness/spirituality dimensions exert both positive and negative effects on the perception of environmental risks and ways of coping with the impacts of rapid environmental changes.

  11. Diversity and structure of microcrustacean assemblages (Cladocera and Copepoda and limnological variability in perennial and intermittent pools in a semi-arid region, Bahia, Brazil

    Directory of Open Access Journals (Sweden)

    Nadson R. Simões

    2011-12-01

    Full Text Available Temporary wetlands undergo recurrent drought due to the scarcity of water, which disrupts the hydrological connectivity with adjacent aquatic systems. However, some environments retain water for longer periods, allowing greater persistence of the community. The current study evaluated differences in the microcrustacean assemblages and limnological variability between perennial and intermittent pools in a semi-arid region of Brazil. The abiotic features (water temperature, pH, total alkalinity, electrical conductivity and depth of intermittent pools were affected more than perennial pools due to loss of water volume. This may have contributed to a higher average richness and diversity index in some intermittent pools and differences in the structure of the assemblages. The lowest species richness and diversity were recorded where physical factors, such as a large quantity of suspended solids and variability in the electrical conductivity of the water and pH, make the environment unsuitable for these organisms. These results suggest that community development in intermittent pools is interrupted by the dry season; when the water returns, due to rainfall or rising groundwater, each pond undergoes a different process of colonization. In these circumstances, the biological importance of temporary aquatic environments is clear, since such pools provide shelters and have an important role in the maintenance of the regional diversity of aquatic environments.

  12. Screening of efficient arbuscular mycorrhizal fungi for Azadirachta indica under nursery condition: a step towards afforestation of semi-arid region of western India

    Directory of Open Access Journals (Sweden)

    K. Banerjee

    2013-01-01

    Full Text Available To optimize nursery practices for efficient plant production procedures and to keep up to the ever growing demand of seedlings, identification of the most suitable species of arbuscular mycorrhizal fungi (AMF, specific for a given tree species, is clearly a necessary task. Sixty days old seedlings of Neem (Azadirachta indica A. Juss raised in root trainers were inoculated with six species of AMF and a mixed inoculum (consortia and kept in green house. Performances of the treatments on this tree species were evaluated in terms of growth parameters like plant height shoot collar diameter, biomass and phosphorous uptake capabilities. Significant and varied increase in the growth parameters and phosphorous uptake was observed for most of the AMF species against control. Consortia culture was found to be the best suited AMF treatment for A.indica, while Glomus intraradices and Glomus mosseae were the best performing single species cultures. It is the first time in the state of Gujarat that a wide variety of AMF species, isolated from the typical semi-arid region of western India, were tested for the best growth performance with one of the most important tree species for the concerned region.

  13. Quantifying the effects of climate variability and human activities on runoff for Kaidu River Basin in arid region of northwest China

    Science.gov (United States)

    Chen, Zhongsheng; Chen, Yaning; Li, Baofu

    2013-02-01

    Much attention has recently been focused on the effects that climate variability and human activities have had on runoff. In this study, data from the Kaidu River Basin in the arid region of northwest China were analyzed to investigate changes in annual runoff during the period of 1960-2009. The nonparametric Mann-Kendall test and the Mann-Kendall-Sneyers test were used to identify trend and step change point in the annual runoff. It was found that the basin had a significant increasing trend in annual runoff. Step change point in annual runoff was identified in the basin, which occurred in the year around 1993 dividing the long-term runoff series into a natural period (1960-1993) and a human-induced period (1994-2009). Then, the hydrologic sensitivity analysis method was employed to evaluate the effects of climate variability and human activities on mean annual runoff for the human-induced period based on precipitation and potential evapotranspiration. In 1994-2009, climate variability was the main factor that increased runoff with contribution of 90.5 %, while the increasing percentage due to human activities only accounted for 9.5 %, showing that runoff in the Kaidu River Basin is more sensitive to climate variability than human activities. This study quantitatively distinguishes the effects between climate variability and human activities on runoff, which can do duty for a reference for regional water resources assessment and management.

  14. Isotope study of impact of climatic changes on hydrological cycle in Central Asian and Caspian arid region

    International Nuclear Information System (INIS)

    Ferronsky, V.I.; Polyakov, V.A.; Lobov, A.L.; Batov, V.I.

    2001-01-01

    The problem of replenishment of groundwater and lakes in the Central Asian and Caspian and region during the Late Pleistocene-Holocene transition time on the basis of isotope studies is discussed. Interpretation of the oxygen and carbon isotope record from the palaeogroundwaters and lake sediments shows that during climate cooling over the Eurasian continent its humid zone was extended towards the and regions. In addition, voluminous glaciers were accumulated in the northern and southern mountain regions. Intensive melting of the glaciers during the transition time provided effective replenishment of the aquifers and lakes in the and zone by fresh water. (author)

  15. Thermal Adaptation Methods of Urban Plaza Users in Asia's Hot-Humid Regions: A Taiwan Case Study.

    Science.gov (United States)

    Wu, Chen-Fa; Hsieh, Yen-Fen; Ou, Sheng-Jung

    2015-10-27

    Thermal adaptation studies provide researchers great insight to help understand how people respond to thermal discomfort. This research aims to assess outdoor urban plaza conditions in hot and humid regions of Asia by conducting an evaluation of thermal adaptation. We also propose that questionnaire items are appropriate for determining thermal adaptation strategies adopted by urban plaza users. A literature review was conducted and first hand data collected by field observations and interviews used to collect information on thermal adaptation strategies. Item analysis--Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA)--were applied to refine the questionnaire items and determine the reliability of the questionnaire evaluation procedure. The reliability and validity of items and constructing process were also analyzed. Then, researchers facilitated an evaluation procedure for assessing the thermal adaptation strategies of urban plaza users in hot and humid regions of Asia and formulated a questionnaire survey that was distributed in Taichung's Municipal Plaza in Taiwan. Results showed that most users responded with behavioral adaptation when experiencing thermal discomfort. However, if the thermal discomfort could not be alleviated, they then adopted psychological strategies. In conclusion, the evaluation procedure for assessing thermal adaptation strategies and the questionnaire developed in this study can be applied to future research on thermal adaptation strategies adopted by urban plaza users in hot and humid regions of Asia.

  16. Net CO2 and water exchanges of trees and grasses in a semi-arid region (Gourma, Mali)

    Science.gov (United States)

    Le Dantec, Valérie; Kergoat, Laurent; Timouk, Franck; Hiernaux, Pierre; Mougin, Eric

    2010-05-01

    An improved understanding of plant and soil processes is critical to predict land surface-atmosphere water exchanges, especially in semi-arid environments, where knowledge is still severely lacking. Within the frame of the African Monsoon Multidisciplinary Project (AMMA), eddy covariance and sapflow stations have been installed to document the intensity, the temporal variability and the main drivers of net CO2 fluxes, water fluxes and contribution of the trees to these fluxes in a pastoral Sahelian landscape. Indeed, although the importance of vegetation in the West African monsoon system has long been postulated, extremely few data were available sofar to test and develop land surface models. In particular, data documenting seasonal and inter-annual dynamics of vegetation/atmosphere exchanges did not exist at 15° N in West Africa before AMMA. The site is located in the Gourma, Mali. Vegetation in this area is sparse and mainly composed of annual grasses and forbs, and trees. Vegetation is organized according to soil type and lateral water redistribution, with bare soil with scattered trees on shallow soils and rocky outcrops (35% of the area), annual grasses and scattered trees on sandy soils (65% of the area), and more dense canopies of grasses and trees growing in valley bottoms over clay soil. To quantify tree transpiration in the overall evapotranspiration flux, sapflow measurements, associated to soil moisture measurements, have been conducted on the main tree species (Acacia senegal, A. seyal, A. raddiana, Combretum glutinosum, Balanites aegyptiaca) in a grassland site and in an open forest site, where eddy covariance fluxes measured the total flux. Using this dataset, we have studied the effects of plant diversity on carbon and water fluxes at the foot-print scale and seasonal dynamics of fluxes due to plant phenology and variations of soil water content (SWC). Carbon fluxes were documented as well, over two years. NEE was close to 0 during the dry season

  17. Seasonal characterization of CDOM for lakes in semi-arid regions of Northeast China using excitation-emission matrices fluorescence and parallel factor analysis (EEM-PARAFAC)

    Science.gov (United States)

    Zhao, Y.; Song, K.; Wen, Z.; Li, L.; Zang, S.; Shao, T.; Li, S.; Du, J.

    2015-04-01

    The seasonal characteristics of fluorescence components in CDOM for lakes in the semi-arid region of Northeast China were examined by excitation-emission matrices fluorescence and parallel factor analysis (EEM-PARAFAC). Two humic-like peaks C1 (Ex/Em = 230, 300/425 nm) and C2 (Ex/Em = 255, 350/460 nm) and two protein-like B (Ex/Em = 220, 275/320 nm) and T (Ex/Em = 225, 290/360 nm) peaks were identified using PARAFAC. The average fluorescence intensity of the four components differed with seasonal variation from June and August 2013 to February and April 2014. The total fluorescence intensity significantly varied from 2.54 ± 0.68 nm-1 in June to the mean value 1.93 ± 0.70 nm-1 in August 2013, and then increased to 2.34 ± 0.92 nm-1 in February and reduced to the lowest 1.57 ± 0.55 nm-1 in April 2014. In general, the fluorescence intensity was dominated by peak C1, indicating that most part of CDOM for inland waters being investigated in this study was originated from phytoplankton degradation. The lowest C2 represents only a small portion of CDOM from terrestrial imported organic matter to water bodies through rainwash and soil leaching. The two protein-like intensities (B and T) formed in situ through microbial activity have almost the same intensity. Especially, in August 2013 and February 2014, the two protein-like peaks showed obviously difference from other seasons and the highest C1 (1.02 nm-1) was present in February 2014. Components 1 and 2 exhibited strong linear correlation (R2 = 0.633). There were significantly positive linear relationships between CDOM absorption coefficients a(254) (R2 = 0.72, 0.46, p DOC. However, almost no obvious correlation was found between salinity and EEM-PARAFAC extracted components except for C3 (R2 = 0.469). Results from this investigation demonstrate that the EEM-PARAFAC technique can be used to evaluate the seasonal dynamics of CDOM fluorescence components for inland waters in semi-arid regions of Northeast China.

  18. Dynamics and sources of soil organic C following afforestation of croplands with poplar in a semi-arid region in northeast China.

    Directory of Open Access Journals (Sweden)

    Ya-Lin Hu

    Full Text Available Afforestation of former croplands has been proposed as a promising way to mitigate rising atmospheric CO2 concentration in view of the commitment to the Kyoto Protocol. Central to this C sequestration is the dynamics of soil organic C (SOC storage and stability with the development of afforested plantations. Our previous study showed that SOC storage was not changed after afforestation except for the 0-10 cm layer in a semi-arid region of Keerqin Sandy Lands, northeast China. In this study, soil organic C was further separated into light and heavy fractions using the density fractionation method, and their organic C concentration and (13C signature were analyzed to investigate the turnover of old vs. new SOC in the afforested soils. Surface layer (0-10 cm soil samples were collected from 14 paired plots of poplar (Populus × xiaozhuanica W. Y. Hsu & Liang plantations with different stand basal areas (the sum of the cross-sectional area of all live trees in a stand, ranging from 0.2 to 32.6 m(2 ha(-1, and reference maize (Zea mays L. croplands at the same sites as our previous study. Soil ΔC stocks (ΔC refers to the difference in SOC content between a poplar plantation and the paired cropland in bulk soil and light fraction were positively correlated with stand basal area (R (2 = 0.48, p<0.01 and R (2 = 0.40, p = 0.02, respectively, but not for the heavy fraction. SOCcrop (SOC derived from crops contents in the light and heavy fractions in poplar plantations were significantly lower as compared with SOC contents in croplands, but tree-derived C in bulk soil, light and heavy fraction pools increased gradually with increasing stand basal area after afforestation. Our study indicated that cropland afforestation could sequester new C derived from trees into surface mineral soil, but did not enhance the stability of SOC due to a fast turnover of SOC in this semi-arid region.

  19. Assessing the evolution of oases in arid regions by reconstructing their historic spatio-temporal distribution: a case study of the Heihe River Basin, China

    Science.gov (United States)

    Xie, Yaowen; Wang, Guisheng; Wang, Xueqiang; Fan, Peilei

    2017-12-01

    Oasis evolution, one of the most obvious surface processes in arid regions, affects various aspects of the regional environment, such as hydrological processes, ecological conditions, and microclimates. In this paper, the historical spatio-temporal evolution of the cultivated oases in the Heihe River Basin, the second largest inland watershed in the northwest of China, was assessed using multidisciplinary methods and data from multiple sources, including historical literature, ancient sites, maps and remotely sensed images. The findings show that cultivated oases were first developed on a large scale during the Han Dynasty (121 BC-220) and then gradually decreased in extent from the Six Dynasties period (220-581) to the Sui-Tang period (581-907), reaching a minimum in the Song-Yuan period (960-1368). An abrupt revival occurred during the Ming Dynasty (1368-1644) and continued through the Qing Dynasty (1644-1911), and during the period of the Republic of China (1912-1949), oasis development reached its greatest peak of the entire historical period. The oasis areas during seven major historical periods, i.e., Han, Six Dynasties, Sui-Tang, Song-Yuan, Ming, Qing, and Republic of China, are estimated to have been 1703 km2, 1115 km2, 629 km2, 614 km2, 964 km2, 1205 km2, and 1917 km2, respectively. The spatial distribution generally exhibited a continuous sprawl process, with the center of the oases moving gradually from the downstream region to the middle and even upstream regions. The oases along the main river remained stable during most periods, whereas those close to the terminal reaches were subject to frequent variations and even abandonment. Socio-economic factors were the main forces driving the evolution of cultivated oases in the area; among them, political and societal stability, national defense, agricultural policy, population, and technological progress were the most important.

  20. Do Red Edge and Texture Attributes from High-Resolution Satellite Data Improve Wood Volume Estimation in a Semi-Arid Mountainous Region?

    DEFF Research Database (Denmark)

    Schumacher, Paul; Mislimshoeva, Bunafsha; Brenning, Alexander

    2016-01-01

    to overcome this issue. However, clear recommendations on the suitability of specific proxies to provide accurate biomass information in semi-arid to arid environments are still lacking. This study contributes to the understanding of using multispectral high-resolution satellite data (RapidEye), specifically...... red edge and texture attributes, to estimate wood volume in semi-arid ecosystems characterized by scarce vegetation. LASSO (Least Absolute Shrinkage and Selection Operator) and random forest were used as predictive models relating in situ-measured aboveground standing wood volume to satellite data...

  1. Bi-decadal groundwater level trends in a semi-arid south indian region: Declines, causes and management

    Directory of Open Access Journals (Sweden)

    Rajendra P. Sishodia

    2016-12-01

    New hydrological insights for the region: Contrary to common perception of widespread groundwater declines only 22–36% of the wells showed statistically significant declines. The use of well depth during dry well periods may slightly underestimate the number of declining wells (by 1% and rate of decline. Increase in groundwater irrigated area combined with rainfall and power subsidy policy, were the main causative factors for the decline. Groundwater decline after implementation of free-electricity policy in 2004 confirmed the nexus between power subsidy and groundwater. These declines are likely to worsen due to future well drillings. Trends in other regions with similar hydro-geologic conditions need to be analyzed to verify groundwater declines and its linkages with power subsidy. Once established, reforms in power subsidy and well permit policy along with conversion to efficient micro–irrigation may be needed to maintain or enhance groundwater availability in the crystalline aquifer region of India (240 million ha.

  2. Hydrological connectivity of perched aquifers and regional aquifers in semi-arid environments: a case study from Namibia

    Science.gov (United States)

    Hamutoko, J. T.; Wanke, H.

    2017-12-01

    Integrated isotopic and hydrological tracers along with standard hydrological data are used to understand complex dry land hydrological processes on different spatial and temporal scales. The objective of this study is to analyse the relationship between the perched aquifers and the regional aquifer using hydrochemical data and isotopic composition in the Cuvelai-Etosha Basin in Namibia. This relation between the aquifers will aid in understanding groundwater recharge processes and flow dynamics. Perched aquifers are discontinuous shallow aquifers with water level ranging from 0 to 30 meters below ground level. The regional aquifer occurs in semi-consolidated sandstone at depths between about 60 and 160 meters below ground level. Water samples were collected from both aquifers in 10 villages and were analysed for major ions and stable isotopes. The results show overlapping hydrochemistry and isotopic compositions of both aquifers in 8 villages which suggest the possibility of perched aquifer water infiltrating into the regional aquifer. In two villages the hydrochemistry and isotopic composition of the aquifers are totally different and this suggests that there is no interaction between this aquifers. Areas where perched aquifers are connected to regional aquifers maybe recharge zones. These finding have important implications for groundwater resource management.

  3. Arid Zone Hydrology

    Science.gov (United States)

    Arid zone hydrology encompasses a wide range of topics and hydro-meteorological and ecological characteristics. Although arid and semi-arid watersheds perform the same functions as those in humid environments, their hydrology and sediment transport characteristics cannot be readily predicted by inf...

  4. Attribute Analysis of Aridity Variability in North Xinjiang, China

    Directory of Open Access Journals (Sweden)

    Yanfeng Wu

    2016-01-01

    Full Text Available Identifying the dominant meteorological factors affecting aridity variability can improve our understanding of climate change and its future trend in arid and semiarid regions. This study investigated the spatiotemporal aridity variability in North Xinjiang, China, from 1961 to 2013, based on the UNESCO aridity index (precipitation/potential evapotranspiration, and analyzed its association with meteorological factors. The results suggest that North Xinjiang is becoming more humid with an increasing trend in aridity index. Precipitation, temperature, and relative humidity have positive correlation with aridity, and evapotranspiration, sunshine hours, and wind speed have negative correlation with aridity. Wind speed and sunshine hours have a higher sensitivity and more contribution to aridity. This study provides an understanding of the effect of recent climate change on drought in northwest China.

  5. Landscape connectivity among remnant populations of guanaco (Lama guanicoe Müller, 1776) in an arid region of Chile impacted by global change.

    Science.gov (United States)

    Espinosa, Mara I; Gouin, Nicolas; Squeo, Francisco A; López, David; Bertin, Angéline

    2018-01-01

    Connectivity between populations plays a key role in the long-term persistence of species in fragmented habitats. This is of particular concern for biodiversity preservation in drylands, since water limited landscapes are typically characterized by little suitable habitat cover, high habitat fragmentation, harsh matrices, and are being rapidly degraded at a global scale. In this study, we modelled landscape connectivity between 11 guanaco Lama guanicoe populations in Chile's arid Norte Chico, a region that supports the last remnant coastal populations of this emblematic herbivore indigenous to South America. We produced a habitat suitability model to derive a regional surface resistance map, and used circuit theory to map functional connectivity, investigate the relative isolation between populations, and identify those that contribute most to the patch connectivity network. Predicted suitable habitat for L. guanicoe represented about 25% of the study region (i.e., 29,173 km 2 ) and was heterogeneously distributed along a continuous stretch along the Andes, and discontinuous patches along the coast. As a result, we found that high connectivity current flows in the mid and high Andes formed a wide, continuous connectivity corridor, enabling connectivity between all high Andean populations. Coastal populations, in contrast, were more isolated. These groups demonstrate no inter-population connectivity between themselves, only with higher altitude populations, and for two of them, animal movement was linked to the effectiveness of wildlife crossings along the Pan-American highway. Our results indicate that functional connectivity is an issue of concern for L. guanicoe in Chile's Norte Chico, implying that future conservation and management plans should emphasize strategies aimed at conserving functional connectivity between coastal and Andean populations, as well as the protection of habitat patches likely to act as stepping stones within the connectivity network.

  6. Landscape connectivity among remnant populations of guanaco (Lama guanicoe Müller, 1776 in an arid region of Chile impacted by global change

    Directory of Open Access Journals (Sweden)

    Mara I. Espinosa

    2018-03-01

    Full Text Available Connectivity between populations plays a key role in the long-term persistence of species in fragmented habitats. This is of particular concern for biodiversity preservation in drylands, since water limited landscapes are typically characterized by little suitable habitat cover, high habitat fragmentation, harsh matrices, and are being rapidly degraded at a global scale. In this study, we modelled landscape connectivity between 11 guanaco Lama guanicoe populations in Chile’s arid Norte Chico, a region that supports the last remnant coastal populations of this emblematic herbivore indigenous to South America. We produced a habitat suitability model to derive a regional surface resistance map, and used circuit theory to map functional connectivity, investigate the relative isolation between populations, and identify those that contribute most to the patch connectivity network. Predicted suitable habitat for L. guanicoe represented about 25% of the study region (i.e., 29,173 km2 and was heterogeneously distributed along a continuous stretch along the Andes, and discontinuous patches along the coast. As a result, we found that high connectivity current flows in the mid and high Andes formed a wide, continuous connectivity corridor, enabling connectivity between all high Andean populations. Coastal populations, in contrast, were more isolated. These groups demonstrate no inter-population connectivity between themselves, only with higher altitude populations, and for two of them, animal movement was linked to the effectiveness of wildlife crossings along the Pan-American highway. Our results indicate that functional connectivity is an issue of concern for L. guanicoe in Chile’s Norte Chico, implying that future conservation and management plans should emphasize strategies aimed at conserving functional connectivity between coastal and Andean populations, as well as the protection of habitat patches likely to act as stepping stones within the

  7. Appraisal of nuclear waste isolation in the vadose zone in arid and semiarid regions (with emphasis on the Nevada Test Site)

    International Nuclear Information System (INIS)

    Wollenberg, H.A.; Wang, J.S.Y.; Korbin, G.

    1983-05-01

    An appraisal was made of the concept of isolating high-level radioactive waste in the vadose zone of alluvial-filled valleys and tuffaceous rocks of the Basin and Range geomorphic province. Principal attributes of these terranes are: (1) low population density, (2) low moisture influx, (3) a deep water table, (4) the presence of sorptive rocks, and (5) relative ease of construction. Concerns about heat effects of waste on unsaturated rocks of relatively low thermal conductivity are considered. Calculations show that a standard 2000-acre repository with a thermal loading of 40 kW/acre in partially saturated alluvium or tuff would experience an average temperature rise of less than 100 0 C above the initial temperature. The actual maximum temperature would depend strongly on the emplacement geometry. Concerns about seismicity, volcanism, and future climatic change are also mitigated. The conclusion reached in this appraisal is that unsaturated zones in alluvium and tuff of arid regions should be investigated as comprehensively as other geologic settings considered to be potential repository sites

  8. Modelling rainfall runoff relations using HEC-HMS in a semi-arid region: Case study in Ain Sefra watershed, Ksour Mountains (SW Algeria

    Directory of Open Access Journals (Sweden)

    Derdour Abdessamed

    2018-03-01

    Full Text Available Ain Sefra is one of the Algerian cities that had been experienced several devastating floods during the past 100 years. The purpose of this study is to simulate runoff in the semi-arid region of Ain Sefra watershed through the employing of the Hydrologic Engineering Center – Hydrologic Modelling System (HEC-HMS. In this paper, the frequency storm is used for the meteorological model, the Soil Conservation Service – curve number (SCS-CN is selected to calculate the loss rate and Soil Conservation Service unit hydrograph method have been applied to simulate the runoff rate. After calibration and validation, the simulated peak discharges were very close with observed values. The Nash–Sutcliffe efficiency coefficient was 0.95, indicates that the hydrological modeling results are satisfactory and accepted for simulation of rainfall-runoff. The peak discharges obtained for the 10, 50, 100 and 1000 year storms are respectively 425.8, 750.5, 904.3 and 1328.3 m3∙s−1.

  9. [Irrigated perimeters as a geopolitical strategy for the development of the semi-arid region and its implications for health, labor and the environment].

    Science.gov (United States)

    Pontes, Andrezza Graziella Veríssimo; Gadelha, Diego; Freitas, Bernadete Maria Coêlho; Rigotto, Raquel Maria; Ferreira, Marcelo José Monteiro

    2013-11-01

    An analysis was made of irrigated perimeters as a geopolitical strategy for expanding Brazilian agricultural frontiers and the "development" of the northeastern semi-arid region with respect to social determinants in health in rural communities. Research was conducted in the Chapada do Apodi in the states of Ceará and Rio Grande do Norte between 2007 and 2011. Various research techniques and tools were adopted, such as research-action, ethnographic studies, questionnaires and laboratory exams, water contamination analyses, social cartography and focal groups. In the context of agribusiness expansion, it was revealed that public policies of irrigation have had consequences for health, labor and the environment with the implementation of the Jaguaribe-Apodi Irrigated Perimeter in Ceará. The social and environmental conflict and resistance in the phase prior to the installation of the Santa Cruz do Apodi Irrigated Perimeter in Rio Grande do Norte was significant as it had consequences for the health-disease process on rural communities. It is important for the evaluation of public irrigation policies to consider the impacts of the perimeters on the lifestyle, labor, health and the environment of the affected territories.

  10. Modeling interactions between saturated and un-saturated zones by Hydrus-1D in semi-arid regions (plain of Kairouan, Central Tunisia).

    Science.gov (United States)

    Saâdi, Mariem; Zghibi, Adel; Kanzari, Sabri

    2018-02-24

    In semi-arid areas like the Kairouan region, salinization has become an increasing concern because of the constant irrigation with saline water and over use of groundwater resources, soils, and aquifers. In this study, a methodology has been developed to evaluate groundwater contamination risk based on the unsaturated zone hydraulic properties. Two soil profiles with different ranges of salinity, one located in the north of the plain and another one in the south of plain (each 30 m deep) and both characterized by direct recharge of the aquifer, were chosen. Simulations were conducted with Hydrus-1D code using measured precipitation data for the period 1998-2003 and calculated evapotranspiration for both chosen profiles. Four combinations of initial conditions of water content and salt concentration were used for the simulation process in order to find the best match between simulated and measured values. The success of the calibration of Hydrus-1D allowed the investigation of some scenarios in order to assess the contamination risk under different natural conditions. The aquifer risk contamination is related to the natural conditions where it increased while facing climate change and temperature increase and decreased in the presence of a clay layer. Hydrus-1D was a useful tool to predict the groundwater level and quality in the case of a direct recharge and in the absence of any information related to the soil layers except for the texture.

  11. Appraisal of nuclear waste isolation in the vadose zone in arid and semiarid regions (with emphasis on the Nevada Test Site)

    Energy Technology Data Exchange (ETDEWEB)

    Wollenberg, H.A.; Wang, J.S.Y.; Korbin, G.

    1983-05-01

    An appraisal was made of the concept of isolating high-level radioactive waste in the vadose zone of alluvial-filled valleys and tuffaceous rocks of the Basin and Range geomorphic province. Principal attributes of these terranes are: (1) low population density, (2) low moisture influx, (3) a deep water table, (4) the presence of sorptive rocks, and (5) relative ease of construction. Concerns about heat effects of waste on unsaturated rocks of relatively low thermal conductivity are considered. Calculations show that a standard 2000-acre repository with a thermal loading of 40 kW/acre in partially saturated alluvium or tuff would experience an average temperature rise of less than 100{sup 0}C above the initial temperature. The actual maximum temperature would depend strongly on the emplacement geometry. Concerns about seismicity, volcanism, and future climatic change are also mitigated. The conclusion reached in this appraisal is that unsaturated zones in alluvium and tuff of arid regions should be investigated as comprehensively as other geologic settings considered to be potential repository sites.

  12. Birds and fish as bioindicators of tourist disturbance in springs in semi-arid regions in Mexico: a basis for management

    Directory of Open Access Journals (Sweden)

    Palacio-Núñez, J.

    2007-06-01

    Full Text Available Tourist disturbance in semi–arid springs was analysed; birds and fish were selected as bioindicators. Media Luna spring is the biggest and most spatially complex system in the region, with the highest biodiversity levels and tourist use. Areas with the highest bird species richness and abundances showed highest structural heterogeneity and least direct human impact. No differences in species richness of fish were observed between sectors and the most abundant species were found in the sectors least perturbed by human activity. Factors that explained the bird distribution were the species´ tolerance to the effects of direct tourism (noise and direct presence of people and habitat quality, mainly riparian vegetation. Aquatic vegetation condition was very important for fish. Six bird species and two fish species were relevant as indicators of the habitat quality related to human impact. Anthropic disturbance such as tree plantation favoured some bird species, whereas aquatic vegetation removal was favourable for some fish species, such as the endemic Cichlasoma bartoni, however, both types of disturbance were unfavourable for other species; riparian vegetation removal was negative for both groups. Controlled tourism promotes good conditions for C. bartoni establishment. Efficient conservation measures such as limiting touristic distribution are necessary for all species, especially for the fish community, in order to conserve biodiversity in general.

  13. Effect of synthetic and natural water-absorbing soil amendments on photosynthesis characteristics and tuber nutritional quality of potato in a semi-arid region.

    Science.gov (United States)

    Xu, Shengtao; Zhang, Lei; McLaughlin, Neil B; Mi, Junzhen; Chen, Qin; Liu, Jinghui

    2016-02-01

    The effect of water-absorbing soil amendments on photosynthesis characteristics and tuber nutritional quality was investigated in a field experiment in a semi-arid region in northern China in 2010-2012. Treatments included two synthetic water-absorbing amendments, potassium polyacrylate (PAA) and polyacrylamide (PAM), and one natural amendment, humic acid (HA), both as single amendments and compound amendments (HA combined with PAA or PAM), and a no amendment control. Soil amendments had a highly significant effect (P ≤ 0.01) on photosynthesis characteristics, dry biomass, crop root/shoot (R/S) ratio and tuber nutritional quality. They improved both dry biomass above ground and dry biomass underground in the whole growing season by 4.6-31.2 and 1.1-83.1% respectively in all three years. Crop R/S ratio was reduced in the early growing season by 2.0-29.4% and increased in the later growing season by 2.3-32.6%. Soil amendments improved leaf soil plant analysis development value, net photosynthesis rate, stomatal conductance and transpiration rate by 1.4-17.0, 5.1-45.9, 2.4-90.6 and 2.0-22.6% respectively and reduced intercellular CO2 concentration by 2.1-19.5% in all three years. Amendment treatment with PAM + HA always had the greatest effect on photosynthesis characteristics and tuber nutritional quality among all amendment treatments and thus merits further research. © 2015 Society of Chemical Industry.

  14. Genetic Variability and Symbiotic Efficiency of Erythrina velutina Willd. Root Nodule Bacteria from the Semi-Arid Region in Northeastern Brazil

    Directory of Open Access Journals (Sweden)

    Kelly Alexsandra Souza Menezes

    Full Text Available ABSTRACT Legume-rhizobia symbiosis is a cross-kingdom association that results in large amounts of nitrogen incorporated in food webs. For the Brazilian semi-arid region, data on genetic variability and symbiotic efficiency of Papilionoidae rhizobial communities are very scarce. The aim of this study was to evaluate the genetic variability and the symbiotic efficiency of eight rhizobial isolates obtained from “mulungu” (Erythrina velutina Willd. nodules. For 16S rRNA gene sequencing, the genomic DNA was extracted using a commercial kit, amplified with universal primers, and subjected to sequencing reactions. For the isolate ESA 71, PCR amplifications for nodC and nodA genes were attempted. Rhizobial efficiency was assessed by two greenhouse experiments. The first assay was carried out under gnotobiotic conditions, with sterile sand as a substrate; the second experiment was conducted in a non-sterile soil. For both experiments, the inoculation treatments consisted of a single inoculation of each isolate, in addition to a treatment with Bradyrhizobium elkanii BR 5609 as a reference strain. Furthermore, two non-inoculated control treatments, supplied and not supplied with mineral N, were also evaluated. Bacterial identification indicated that both α and β-rhizobia could be found in “mulungu” root nodules. Three isolates where classified within the Rhizobium genus, four bacteria belonged to Bradyrhizobium and one isolate clustered with Burkholderia. Positive amplification of an intragenic fragment of the nodA gene using a primer set to β-rhizobia could be found for ESA 71 (Burkholderia. All bacterial isolates were effective in colonizing “mulungu” roots. In the first experiment, all inoculated treatments and N fertilization increased the N concentration in “mulungu” shoot tissues. For total N in the shoots, the isolates ESA 70, ESA 72, and ESA 75 stood out. In the non-sterile substrate experiment, the isolates ESA 70, ESA 71, ESA

  15. Effects of a Reservoir Water on the GW Quality in a Coastal Aquifer of Semi-arid Region, North-east of Tunisia

    Science.gov (United States)

    Uchida, C.; Kawachi, A.; Tsujimura, M.; Tarhouni, J.

    2015-12-01

    This study investigated effects of a reservoir water in a salinized shallow aquifer based on spatial distribution of geochemical properties in groundwater (GW). In many coastal shallow aquifers of arid and semi-arid regions, groundwater table (GWT) depression and salinization have occurred due to GW overexploitation. In Korba aquifer, north-east of Tunisia, after a dam reservoir has been constructed in order to assure a water resource for irrigation, improvement of GW level and quality have been observed in the downstream area of the dam (area-A), while the GW in the other area (area-B) still has high salinity. This study, therefore, aimed to investigate the effects of the reservoir water on the GW quality. In June 2013, water quality survey and sampling were carried out at 60 wells (GW), a dam reservoir, river and the sea. Major ions, boron, bromide, and oxygen-18 and deuterium in collected samples were analyzed. From the results, in the area-B, the GWT was lower than the sea level and the high salinity were observed. The Br- concentration of the GW was correlated with the Cl- concentration, and the values of B/Cl- and Br-/Cl- of the GW were similar to the seawater. Since the GWT depression allowed the seawater to intrude into the aquifer, the GW salinization occurred in this area. On the other hand, in the area-A, GWT was higher than the seawater level, and the Na+ and Cl- concentrations were lower than the area-B. Especially, in the irrigated areas by using the reservoir water, the isotopic values, B/Cl- and Br-/Cl- of the GW were relatively higher than the others. The reservoir water has high isotopic values due to evaporation effect, and the B/Cl- and Br-/Cl- values become higher due to organic matters in sediment of the reservoir or soil in the filtration process. Thus, in addition to the direct infiltration from the reservoir into the aquifer, irrigation using a reservoir water probably has a positive impact on the GW quality in this area.

  16. A dynamical characterization of the uncertainty in projections of regional precipitation change in the semi-arid tropics

    Science.gov (United States)

    Giannini, A.

    2016-12-01

    The uncertainty in CMIP multi-model ensembles of regional precipitation change in tropical regions is well known: taken at face value, models do not agree on the direction of precipitation change. Consequently, in adaptation discourse, either projections are discounted, e.g., by giving more relevance to temperature projections, or outcomes are grossly misrepresented, e.g., in extrapolating recent drought into the long-term future. That this is an unsatisfactory state of affairs, given the dominant role of precipitation in shaping climate-sensitive human endeavors in the tropics, is an understatement.Here I will provide a dynamical characterization of the uncertainty in regional precipitation projections that exploits the CMIP multi-model ensembles. This characterization is based on decomposing the moisture budget and relating its terms to the influence of the oceans, specifically to the roles of moisture supply and stabilization of the vertical profile. I will discuss some preliminary findings highlighting the relevance of lessons learned from seasonal-to-interannual prediction. One such lesson is to go beyond the projection taken at face value, and understand physical processes, specifically, the role of the oceans, in order to be able to make qualitative arguments, in addition to quantitative predictions. One other lesson is to abandon the search for the "best model" and exploit the multi-model ensemble to characterize "emergent constraints".

  17. Water conservation for semi-arid rangelands

    International Nuclear Information System (INIS)

    Willis, W.O.

    1983-01-01

    Water deficiency is most often the cause for low forage production on rangelands in semi-arid and arid regions. Water conservation methods have been developed but additional research is needed to develop the best management practices for various climatic regions. Poor management is another major cause of low rangeland production. Better management, including the application of research findings, depends on attitudes, policies, adaptability of findings, resources for implementation and a good understanding of the governing biotic and abiotic factors. (author)

  18. Development of hardy sorghum cultivars for the arid and semi arid ...

    African Journals Online (AJOL)

    Development of hardy sorghum cultivars for the arid and semi arid regions. MN Makobe, EM Kahangi, AK Misra, MO Imbuga. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online. HOW TO USE AJOL.

  19. Study of emission process in hot, optically thin plasma: application to solar active regions

    International Nuclear Information System (INIS)

    Steenman-Clark, Lois.

    1983-06-01

    Analysis of soft X-ray got in hot and weak density plasmas, such as those in TOKAMAKS and in solar flares, needs a detailed knowledge of emission processes. In this work are presented spectroscopic diagnostics which can be deduced from such spectra analysis and results are applied to magnesium solar spectrum analysis. An important improvement is brought to collisional calculation corresponding to forbidden line populating. For this line, The relative importance of autoionizing states effect, called also resonance effect is studied [fr

  20. ORGANIC MATTER FRACTIONS OF AN IRRIGATED OXISOL UNDER NO - TILL AND CONVENTIONAL TILLAGE IN THE BRAZILIAN SEMI - ARID REGION

    Directory of Open Access Journals (Sweden)

    RAFAEL PEREIRA SALES

    2017-01-01

    Full Text Available The replacement of natural vegetation by crop systems directly impacts the soil organic matter fractions. The objective of this study was to evaluate the total organic carbon (TOC and nitrogen (TN contents in different fractions of the soil organic matter (SOM of an Oxisol of the Brazilian semiarid region under different irrigated crops and different soil management systems. Seven treatments were evaluated, which consisted of two soil management systems (no - till and conventional tillage and three crops (maize, sunflower and sorghum, using as reference the soil under a native forest (NF. The summer crops preceded common bean crops in the autumn - winter. The total organic carbon content, total nitrogen, carbon content in humic substances and their constituents (fulvic acids, humic acids and humin and labile, non - labile and water - soluble carbon contents were evaluated two years and three months after the experiment implementation to determine the carbon lability (L lability index (LI, partitioning index (CPI and management index (CMI. The greatest carbon, nitrogen and organic matter contents in the soil surface layer (0.00 - 0.05 m were found in crops under no - till system (NTS, especially maize. The crops under NTS presented greater carbon content in humic substances than the conventional tillage system (CTS ones in the layer 0.05 - 0.10 m. The crops under NTS presented greater sustainability in the Brazilian semiarid region compared with those under CTS, as shown by their higher CMI in the soil surface layer.

  1. Diagnosing land management and climate change impacts on snowmelt in semi-arid agricultural cold regions with an improved snowmelt model

    Science.gov (United States)

    Harder, P.; Pomeroy, J. W.; Helgason, W.

    2017-12-01

    Spring snowmelt is the most important hydrological event in semi-arid agricultural cold regions, recharging soil moisture and generating the majority of annual runoff. Adoption of no-till agricultural practices means vast areas of the Canadian Prairies, and other analogous regions, are characterized by standing crop stubble. The emergence of stubble during snowmelt will have important implications for the snowpack energy balance. In addition, spatiotemporally dynamic snowcover heterogeneity leads to enhancement of turbulent flux contributions to melt by advection of energy from warm moist bare ground to snow. Stubble emergence and advection are generally unaccounted for in snow models. To address these challenges a stubble-snow-atmosphere surface energy balance model is developed that relates stubble parameters to the snow surface energy balance. Existing fractal understandings of snowcover geometry are applied to a conceptualized boundary layer integration model to estimate a sensible and latent heat advection efficiency. The small-scale nature of stubble-snow-atmosphere interactions makes direct validation of the energy balance terms challenging. However, the energy balance estimates are assessed by comparing to measured snow and stubble surface temperatures, snow surface incoming shortwave radiation and areal average turbulent fluxes. Advection estimates are validated from a two-dimensional air temperature, water vapor and windspeed profiles. Snowcover geometry relationships are validated/updated with unmanned air vehicle observations. Observations for model assessment occurred in 2015 and 2016 on wheat and canola stubble fields in north-central Saskatchewan, Canada. The model is not calibrated to melt rates, yet compares well with available observations, providing confidence in the model structure and parameterization. Sensitivity analysis using the model revealed compensatory relationships in energy balance terms resulting in limited reduction of energy

  2. Drinking water pollution with respective of fluoride in the semi-arid region of Basara, Nirmal district, Telangana State, India

    Directory of Open Access Journals (Sweden)

    Adimalla Narsimha

    2018-02-01

    Full Text Available Fluoride is an essential microelement for human health. Statistically, smaller quantities (1.5 mg/L to fluoride can give rise to a number of adverse effects, including dental fluorosis, skeletal fluorosis, increased rate of bone fractures, decreased birth rates, increased rate of urolithiasis (kidney stones, impaired thyroid function, and impaired development of intelligence in children [1–5]. The data suggested that the north-eastern part of the Basara region having high fluoride concentration, which is unsuitable for drinking purposes. Hence, this unsuitable drinking water cause fluorosis in this Basara and surrounding villages, and especially based on the findings suggests, where the fluoride levels are in below maximum permissible limits that water ingests to the people to avoid further fluorosis.

  3. Drinking water pollution with respective of fluoride in the semi-arid region of Basara, Nirmal district, Telangana State, India.

    Science.gov (United States)

    Narsimha, Adimalla; Sudarshan, Venkatayogi

    2018-02-01

    Fluoride is an essential microelement for human health. Statistically, smaller quantities (water are usually considered to have a beneficial effect on the rate of occurrence of dental caries, particularly among children, but excessive continuous exposure (>1.5 mg/L) to fluoride can give rise to a number of adverse effects, including dental fluorosis, skeletal fluorosis, increased rate of bone fractures, decreased birth rates, increased rate of urolithiasis (kidney stones), impaired thyroid function, and impaired development of intelligence in children [1], [2], [3], [4], [5]. The data suggested that the north-eastern part of the Basara region having high fluoride concentration, which is unsuitable for drinking purposes. Hence, this unsuitable drinking water cause fluorosis in this Basara and surrounding villages, and especially based on the findings suggests, where the fluoride levels are in below maximum permissible limits that water ingests to the people to avoid further fluorosis.

  4. Analysis & Tools to Spur Increased Deployment of “Waste Heat” Rejection/Recycling Hybrid Ground-source Heat Pump Systems in Hot, Arid or Semiarid Climates Like Texas

    Energy Technology Data Exchange (ETDEWEB)

    Masada, Glenn [Univ. of Texas, Austin, TX (United States); Moon, Tess [Univ. of Texas, Austin, TX (United States)

    2013-09-01

    This project team analyzed supplemental heat rejection/recovery (SHR) devices or systems that could be used in hybrid ground source heat pump (HGHP) systems located in arid or semi-arid regions in southwestern U.S. Identification of effective SHR solutions would enhance the deployment of ground source heat pumps (GHP) in these regions. In a parallel effort, the team developed integrated GHP models that coupled the building load, heat pump, and ground loop subsystems and which could be applied to residential and commercial office buildings. Then GHP and HGHP performances could be compared in terms of operational performance and life-cycle costs. Several potential SHR devices were analyzed by applying two strategies: 1) to remove heat directly from the water in the ground loop before it enters the ground and 2) to remove heat in the refrigerant loop of the vapor compression cycle (VCC) of the heat pump so less heat is transferred to the water loop at the condenser of the VCC. Cooling towers, adsorption coolers, and thermoelectric liquid coolers were included in strategy 1, and expanded desuperheaters, thermosyphons, and an optimized VCC were included in strategy 2. Of all SHR devices analyzed, only the cooling tower provided a cost-effective performance enhancement. For the integrated GHP model, the project team selected the building load model HAMBASE and its powerful computational Simulink/MatLab platform, empirical performance map models of the heat pumps based upon manufacturers’ performance data, and a ground loop model developed by Oklahoma State University and rewritten for this project in Simulink/MatLab. The design process used GLHEPRO, also from Oklahoma State University, to size the borehole fields. The building load and ground loop models were compared with simulations from eQuest, ASHRAE 140-2008 standards, EnergyPlus, and GLHEPRO and were found to predict those subsystems’ performance well. The integrated GHP model was applied to a 195m2

  5. Hot emission model for mobile sources: application to the metropolitan region of the city of Santiago, Chile.

    Science.gov (United States)

    Corvalán, Roberto M; Osses, Mauricio; Urrutia, Cristian M

    2002-02-01

    Depending on the final application, several methodologies for traffic emission estimation have been developed. Emission estimation based on total miles traveled or other average factors is a sufficient approach only for extended areas such as national or worldwide areas. For road emission control and strategies design, microscale analysis based on real-world emission estimations is often required. This involves actual driving behavior and emission factors of the local vehicle fleet under study. This paper reports on a microscale model for hot road emissions and its application to the metropolitan region of the city of Santiago, Chile. The methodology considers the street-by-street hot emission estimation with its temporal and spatial distribution. The input data come from experimental emission factors based on local driving patterns and traffic surveys of traffic flows for different vehicle categories. The methodology developed is able to estimate hourly hot road CO, total unburned hydrocarbons (THCs), particulate matter (PM), and NO(x) emissions for predefined day types and vehicle categories.

  6. Ionization processes in the Fe 27 region of hot iron plasma in the field of hard gamma radiation

    International Nuclear Information System (INIS)

    Illarionov, A.F.

    1989-01-01

    A highly ionized hot plasma of an iron 26 56 Fe-type heavy element in the field of hard ionizing gamma-ray radiation is considered. The processes of ionization and recombination are discussed for a plasma consisting of the fully ionized Fe 27 and the hydrogen-like Fe 26 ions of iron in the case of large optical depth of the plasma with respect to the photoionization by gamma-ray quanta. The self-ionization process of a hot plasma with the temperature kT ≅ I (I being the ionization potential), due to the production of the own ionizing gamma-ray quanta, by the free-free (ff) and recombination (fb) radiation mechanisms, is investigated. It is noted that in the stationary situation the process of self-ionization of a hot plasma imposes the restriction upon the plasma temperature, kT<1.5 I. It is shown that the ionization of heavy-ion plasma by the impact of thermal electrons is dominating over the processes of ff- and fb-selfionization of plasma only by the large concentration of hydrogen-like iron at the periphery of the region of fully ionized iron Fe 27

  7. The Neutron-Moisture Meter in Studies of the Effect of Fallow on Water Conservation in Arid Regions

    Energy Technology Data Exchange (ETDEWEB)

    Oezbek, Nurinnisa; Aksoy, Tevfik; Celebi, Gurkan [Radiophysiology and Soil Fertility Department, Faculty of Agriculture, University of Ankara, Ankara (Turkey)

    1967-11-15

    For a long time it has been a common practice for the Central Anatolian farmers to leave half the land fallow the whole year in order to increase the amount of water conserved. The main object of these studies was to ascertain whether fallow has an effect on moisture conservation in soils of this region and if so what was its degree of efficiency on a yearly basis. In view of the intensity and distribution of rainfall Ankara, Konya and Eski$ehir were selected for moisture-measurement areas. Altogether 60 holes were dug and 60 access tubes were used for moisture measurements by a neutron- moisture meter, and they were placed at six different locations on either state farms or a dry-farming experimental station. In each location the first group of access tubes were placed in fallow soil, the second in a wheat field and the third in a wheat field after harvest. Each treatment had three replicates. In all holes the moisture measurements were made at five different depths at intervals of either 15 days or one month. At the beginning of the moisture measurements a separate calibration curve was prepared for each location and for each treatment. The measurements were begun in 1964 and are continuing, but with some variations in the sampling technique. Some physical properties of the soils that were sampled from measurement areas, such as texture, field capacity and wilting point, were determined. Some bulk-density measurements were also made by gamma-ray transmission. The results obtained are averaged and illustrated in tables and figures. Necessary calculations and comparisons were made to show the efficiency of the fallow system in the moisture conservation in this dry soil. The results can be summarized as follows: (1) The total amount of water conserved in the soil down to a depth of 1.80 cm was higher in fallow soil than in the other two cases. This was true for all locations over a period of two years. (2) The amounts of water conserved by the effect of fallow

  8. An analytical framework for extracting hydrological information from time series of small reservoirs in a semi-arid region

    Science.gov (United States)

    Annor, Frank; van de Giesen, Nick; Bogaard, Thom; Eilander, Dirk

    2013-04-01

    small reservoirs in the Upper East Region of Ghana. Reservoirs without obvious large seepage losses (field survey) were selected. To verify this, stable water isotopic samples are collected from groundwater upstream and downstream from the reservoir. By looking at possible enrichment of downstream groundwater, a good estimate of seepage can be made in addition to estimates on evaporation. We estimated the evaporative losses and compared those with field measurements using eddy correlation measurements. Lastly, we determined the cumulative surface runoff curves for the small reservoirs .We will present this analytical framework for extracting hydrological information from time series of small reservoirs and show the first results for our study region of northern Ghana.

  9. Optimization study of a single-effect water–lithium bromide absorption refrigeration system powered by flat-plate collector in hot regions

    International Nuclear Information System (INIS)

    Saleh, A.; Mosa, M.

    2014-01-01

    Highlights: • A comprehensive analysis for optimizing solar absorption system in hot region. • The most important parameter to be controlled is hot source temperature. • Ensuring appropriate choice of parameters, COP of absorption unit exceeds 0.8. • Results show that solar cooling systems are promising in hot regions. • The research aims to play a vital role to promote the use of renewable energy. - Abstract: This investigation has been carried out to present a comprehensive analysis for optimizing the operation of solar absorption system in hot regions. To optimize performance of the system, the hot source temperature should be controlled in function of incident solar radiation, chilled and cooling water temperatures. With an appropriate control, these external conditions can be monitored to detect and implement the actual optimization conditions. Adopting typical values encountered in hot regions, the overall system performance takes its optimal value at temperatures between 75 and 80 °C. It was found that in designing or selecting solar collector, selective coating type is necessary to produce hot water with potential around 80–90 °C needed to optimize operation of absorption unit. By ensuring an appropriate choice of components temperatures, COP of absorption unit can exceed the value 0.8. Cooling water temperature above 40 °C reduces significantly the performance of the unit which requires, under conditions of extremely high external temperatures, dimensioning and selection of condensers and absorbers that guarantee values less than this limit

  10. Effects of hot-iron disbudding, using regional anaesthesia with and without carprofen, on cortisol and behaviour of calves.

    Science.gov (United States)

    Stilwell, G; Lima, M S; Carvalho, R C; Broom, D M

    2012-04-01

    The objective of this study was to assess cortisol and behaviour changes in calves hot-iron disbudded after different analgesic protocols. We assessed the response of 27 calves at 1, 3, 6 and 24 h after disbudding with regional anaesthesia (DA), regional anaesthesia plus carprofen (DAC), disbudded only (D) or sham-disbudded (ND). At 1h cortisol was higher in D compared with all other groups. At 3h DA showed higher cortisol than ND but did not differ from baseline. At 15 min and 1h pain-related behaviours were more frequent in the D group than in all other groups. Group D (3 h) and DA (3 and 6 h) showed more ear flicks and head rubs compared with DAC and ND. We concluded that head rubbing, head shaking and ear flicking are useful behaviours for evaluating pain after hot-iron disbudding. Disbudding causes severe pain in calves and only the association of regional anaesthesia with carprofen assures good welfare for 24 h. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Effects of land conversion from native shrub to pistachio orchard on soil erodibility in an arid region.

    Science.gov (United States)

    Yakupoglu, Tugrul; Gundogan, Recep; Dindaroglu, Turgay; Kara, Zekeriya

    2017-10-29

    Land-use change through degrading natural vegetation for agricultural production adversely affects many of soil properties particularly organic carbon content of soils. The native shrub land and grassland of Gaziantep-Adiyaman plateau that is an important pistachio growing eco-region have been cleared to convert into pistachio orchard for the last 50 to 60 years. In this study, the effects of conversion of natural vegetation into agricultural uses on soil erodibility have been investigated. Soil samples were collected from surface of agricultural fields and adjacent natural vegetation areas, and samples were analyzed for some soil erodibility indices such as dispersion ratio (DR), erosion ratio (ER), structural stability index (SSI), Henin's instability index (I s ), and aggregate size distribution after wet sieving (AggSD). According to the statistical evaluation, these two areas were found as different from each other in terms of erosion indices except for I s index (P < 0.001 for DR and ER or P < 0.01 for SSI). In addition, native shrub land and converted land to agriculture were found different in terms of AggSD in all aggregate size groups. As a contrary to expectations, correlation tests showed that there were no any interaction between soil organic carbon and measured erodibility indices in two areas. In addition, significant relationships were determined between measured variables and soil textural fractions as statistical. These obtaining findings were attributed to changing of textural component distribution and initial aggregate size distribution results from land-use change in the study area. Study results were explained about hierarchical aggregate formation mechanism.

  12. [Capacity of extensive green roof to retain rainwater runoff in hot and humid region.

    Science.gov (United States)

    Liu, Ming Xin; Dai, Se Ping; Zhou, Tian Yang; Ruan, Lin; Zhang, Qiao Song

    2017-02-01

    The water logging has become the environmental problem of major cities with the sharp increase of impermeable urban pavement as the contributing cause. Abroad, the green roof has been widely used as a practical measure to intercept rainwater, yet the capacity of green roof to retain rainwater varies with climate conditions. As the hot and humid climate zone features high temperature, humidity and precipitation, it is meaningful to study the capacity of green roof to retain rainwater under such climatic condition. In this research, 3 plat forms were set up in Guangzhou in rainy and hot summer to test the capability of simple green roof to retain rainwater runoff, and the efficiency of green roof to retain rainwater under local climate conditions was worked out based on the meteorological observation and data measurement during the 13-month test period. The results showed that the simple green roof with a substrate thickness of 30, 50 and 70 mm could retain 27.2%, 30.9% and 32.1% of precipitation and reduce the average peak value by 18.9%, 26.2% and 27.7%, respectively. Given an urban built-up area of 1035.01 km 2 in Guangzhou and a roof area percentage of approximately 37.3% and assuming the green roofs with 30 mm-thick substrate were applied within the area, the light, medium and heavy rain could be delayed at 72.8%, 22.6% and 17.4%, respectively. Accordingly, the rainwater retained could reach up to 14317×10 4 m 3 . It suggested the great potential of the simple green roof in retaining rainwater. The research could serve as reference for the hot and humid climate zone to alleviate water logging and visualize sponge city construction.

  13. The role of economic analysis in groundwater management in semi-arid regions: the case of Nigeria

    Science.gov (United States)

    Acharya, Gayatri

    The aim of this paper is to use an economic framework to derive decision making rules for river basin management with a focus on groundwater resources. Using an example from northern Nigeria, the paper provides an example of how decision making for sustainable water resources management may be facilitated by comparing net benefits and costs across a river basin. It is argued that economic tools can be used to assess the value of water resources in different uses, identify and analyze management scenarios, and provide decision rules for the sustainable use and management of surface and ground water resources in the region. L'objet de cet article est l'utilisation d'un cadre économique pour établir des règles de prise de décision pour la gestion d'un bassin versant prenant en compte les ressources en eau souterraine. À partir d'un exemple du Nigéria septentrional, cet article explique comment une prise de décision pour la gestion durable de ressources en eau peut être facilitée en comparant les bénéfices nets et les coûts sur tout le bassin versant. Il est montré que les outils économiques peuvent être utilisés pour établir la valeur des ressources en eau dans les différents usages, pour identifier et analyser des scénarios de gestion et pour fournir des règles de décision pour un usage et une gestion durables des ressources en eaux de surface et souterraines dans la région. El objetivo de este artículo es utilizar un enfoque económico para deducir reglas de toma de decisión en la gestión de cuencas, haciendo énfasis en los recursos subterráneos. Por medio de un ejemplo del Norte de Nigeria, se ilustra cómo la toma de decisiones orientadas a la gestión sustentable de los recursos hídricos puede ser facilitada si se compara los beneficios netos y los costes en toda la cuenca. Se argumenta que las herramientas económicas pueden servir para establecer el valor de los recursos hídricos destinados a usos diferentes, para identificar y

  14. Determining the Impact of Forest Mortality in Semi-Arid Woodlands on Local and Regional Carbon Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Litvak, Marcy [University of New Mexico

    2018-04-09

    We received funds in July 2012, and with supplemental funds, this funding ended in July 2017. Our overall project goals were to quantify the consequences of pinon mortality for carbon, water and energy exchange in pinon-juniper woodlands. To do this, we have been continuously measuring carbon, water and energy exchange using eddy covariance, over two pinon-juniper woodlands in central New Mexico. In one site, we girdled 1632 trees in the 4 ha surrounding the tower in Sept 2009. The other site, only 5 km away on the same plateau, was left intact, to serve as a control. We used this paired tower approach so we could directly evaluate the differences between how fluxes from disturbed and intact woodlands respond to the exact same climate conditions. In addition to eddy covariance measured fluxes from the two woodlands, we also made sap flux measurements, biomass, gas exchange, and soil respiration fluxes simultaneously in the two sites. The overall objective of this proposal is to measure the carbon and climate forcing consequences of widespread coniferous mortality events in the Southwestern US. We will incorporate these findings into a land surface model to understand the long term carbon dynamics of these mortality events and use remote sensing maps of mortality in PJ woodlands in NM to scale the implications of these events to regional carbon dynamics and atmospheric CO2. In 2013, our control PJ woodland experienced a natural pinon mortality event as bark beetles invaded the area. We received supplemental funds to quantify the extent of the mortality and how it progresses, and to add remotely sensed imagery to aid in this and estimate the loss of biomass at the site due to mortality. Finally, we have been exploring the use of both CLM and SIPNET to analyze how well these models to in representing how these woodlands change following pinon mortality. Here, I present the results of what we have learned in these areas: 1) how carbon, water and energy fluxes, have

  15. Heavy metal accumulation in hot water tanks in a region experiencing coal waste pollution and comparison between regional water systems

    Energy Technology Data Exchange (ETDEWEB)

    Wigginton, A.; McSpirit, S.; Sims, C.D. [University of Kentucky, Lexington, KY (United States). Dept. of Biology

    2007-10-15

    In 2000, a coal slurry impoundment failure in Martin County, Kentucky, caused concerns about contaminants entering municipal water supplies. Water samples taken from impacted and reference area hot water tanks often exceeded US EPA drinking water guidelines. Concentrations of As, Cd, Cr, Cu, Fe, Mn, and Pb had maxima of 119; 51.9; 154; 170,000; 976,000; 8,710; and 12,700 {mu}g/L, respectively. Significantly different metal accumulation between counties indicated this procedure's utility for assessing long-term municipal water quality. Correlations between metal concentrations were strong and consistent for As, Ba, Cd, Cr, Co, and Fe indicating that some metals accumulate proportionally with others.

  16. Irrigated plantations and their effect on energy fluxes in a semi-arid region of Israel - a validated 3-D model simulation

    Science.gov (United States)

    Branch, O.; Warrach-Sagi, K.; Wulfmeyer, V.; Cohen, S.

    2013-11-01

    A large irrigated biomass plantation was simulated in an arid region of Israel within the WRF-NOAH coupled atmospheric/land surface model in order to assess land surface atmosphere feedbacks. Simulations were carried out for the 2012 summer season (JJA). The irrigated plantations were simulated by prescribing tailored land surface and soil/plant parameters, and by implementing a newly devised, controllable sub-surface irrigation scheme within NOAH. Two model cases studies were considered and compared - Impact and Control. Impact simulates a hypothetical 10 km × 10 km irrigated plantation. Control represents a baseline and uses the existing land surface data, where the predominant land surface type in the area is bare desert soil. Central to the study is model validation against observations collected for the study over the same period. Surface meteorological and soil observations were made at a desert site and from a 400 ha Simmondsia chinensis (Jojoba) plantation. Control was validated with data from the desert, and Impact from the Jojoba. Finally, estimations were made of the energy balance, applying two Penman-Monteith based methods along with observed meteorological data. These estimations were compared with simulated energy fluxes. Control simulates the daytime desert surface 2 m air temperatures (T2) with less than 0.2 °C deviation and the vapour pressure deficit (VPD) to within 0.25 hPa. Desert wind speed (U) is simulated to within 0.5 m s-1 and the net surface radiation (Rn) to 25 W m-2. Soil heat flux (G) is not so accurately simulated by Control (up to 30 W m-2 deviation) and 5 cm soil temperatures (ST5) are simulated to within 1.5 °C. Impact simulates daytime T2 over irrigated vegetation to within 1-1.5 °C, the VPD to 0.5 hPa, Rn to 50 W m-2 and ST5 to within 2 °C. Simulated Impact G deviates up to 40 W m-2, highlighting a need for re-parameterisation or better soil classification, but the overall contribution to the energy balance is small (5

  17. Effects of habitat disturbance on the pollination system of Ammopiptanthus mongolicus (Maxim) Cheng f. at the landscape-level in an arid region of Northwest China.

    Science.gov (United States)

    Chen, Min; Zhao, Xue-Yong; Zuo, Xiao-An; Mao, Wei; Qu, Hao; Zhu, Yang-Chun

    2016-05-01

    Ammopiptanthus mongolicus is an ecologically important species in the arid region of Northwest China. Habitat disturbance can significantly affect plant mating success and ultimately species viability. Pollen limitation of plant reproduction occurs in many plant species, particularly those under habitat disturbance. However, previous investigations have demonstrated differences in pollen limitation between conserved and disturbed sites. We compared the phenology, pollen limitation, pollinators and breeding system of both sites to determine whether habitat disturbance has generated changes in these plant components. We found that the species differed in four aspects. First, blooming duration and flowering peak were longer in the disturbed site than in the conserved site. Second, A. mongolicus can be pollen-limited and pollen limitation was more intense in the conserved site than in the disturbed site. Third, Anthophora uljanini was found to be a frequent pollinator in the conserved site, while Apis mellifera was the most effective and frequent flower visitor. More pollinator visits were recorded in the disturbed site, which could explain the differences in reproductive success. Finally, seed set was higher in the disturbed site than in the conserved site. We found that outcrossing was dominant in both sites and that agamospermy and self-pollination played complementary roles to ensure reproduction. Differences in flower production influenced by artificial selection and pollinator type explain the different seed set in both sites, whereas habitat disturbance cause changes differences in the pollination process and limits pollen flow. The balance between artificial management and mating success is crucial to analysis of the pollination process and manipulation of A. mongolicus population size.

  18. Combining hydrology and mosquito population models to identify the drivers of Rift Valley fever emergence in semi-arid regions of West Africa.

    Science.gov (United States)

    Soti, Valérie; Tran, Annelise; Degenne, Pascal; Chevalier, Véronique; Lo Seen, Danny; Thiongane, Yaya; Diallo, Mawlouth; Guégan, Jean-François; Fontenille, Didier

    2012-01-01

    Rift Valley fever (RVF) is a vector-borne viral zoonosis of increasing global importance. RVF virus (RVFV) is transmitted either through exposure to infected animals or through bites from different species of infected mosquitoes, mainly of Aedes and Culex genera. These mosquitoes are very sensitive to environmental conditions, which may determine their presence, biology, and abundance. In East Africa, RVF outbreaks are known to be closely associated with heavy rainfall events, unlike in the semi-arid regions of West Africa where the drivers of RVF emergence remain poorly understood. The assumed importance of temporary ponds and rainfall temporal distribution therefore needs to be investigated. A hydrological model is combined with a mosquito population model to predict the abundance of the two main mosquito species (Aedes vexans and Culex poicilipes) involved in RVFV transmission in Senegal. The study area is an agropastoral zone located in the Ferlo Valley, characterized by a dense network of temporary water ponds which constitute mosquito breeding sites. The hydrological model uses daily rainfall as input to simulate variations of pond surface areas. The mosquito population model is mechanistic, considers both aquatic and adult stages and is driven by pond dynamics. Once validated using hydrological and entomological field data, the model was used to simulate the abundance dynamics of the two mosquito species over a 43-year period (1961-2003). We analysed the predicted dynamics of mosquito populations with regards to the years of main outbreaks. The results showed that the main RVF outbreaks occurred during years with simultaneous high abundances of both species. Our study provides for the first time a mechanistic insight on RVFV transmission in West Africa. It highlights the complementary roles of Aedes vexans and Culex poicilipes mosquitoes in virus transmission, and recommends the identification of rainfall patterns favourable for RVFV amplification.

  19. Local health practices and the knowledge of medicinal plants in a Brazilian semi-arid region: environmental benefits to human health.

    Science.gov (United States)

    Zank, Sofia; Peroni, Nivaldo; de Araújo, Elcida Lima; Hanazaki, Natalia

    2015-02-23

    The concept of eco-cultural health considers the dynamic interaction between humans and ecosystems, emphasizing the implications of the health of the ecosystem for the health and well-being of human populations. Ethnobotanical studies focusing on folk medicine and medicinal plants can contribute to the field of eco-cultural health if they incorporate the perspective and local knowledge of communities. We investigated the local health practices in three rural communities living within the vicinity of a protected area of sustainable use in a semi-arid region of Brazil. We analyzed the opinions of local health experts on the elements that influence human health and on how the environment contributes to this influence. We also analyzed and compared the local knowledge of medicinal plants, as knowledge of this type is an important factor when considering the interaction between environmental and human health. We performed structured interviews and free-listings with 66 local health experts. We used content analysis to systematize the elements of the influences on human health. We compared the richness of the plants cited among communities and analyzed the differences among the three communities regarding the ways in which the plants were obtained and the environments in which plants were collected. The local experts identified several influences of the environment on human health. These influences can be associated with ecosystem services, such as climatic conditions, water and air quality, recreation and medicinal and food resources. We identified 192 medicinal plant species, most of which were gathered from wild ecosystems. The most important environments for the three communities were the plateau mountain and backyards. The informants had a broad and integrated view of health, perceiving the importance of conserving the environment within the National Forest of Araripe for the health and well-being of the local populations.

  20. Combining hydrology and mosquito population models to identify the drivers of Rift Valley fever emergence in semi-arid regions of West Africa.

    Directory of Open Access Journals (Sweden)

    Valérie Soti

    Full Text Available BACKGROUND: Rift Valley fever (RVF is a vector-borne viral zoonosis of increasing global importance. RVF virus (RVFV is transmitted either through exposure to infected animals or through bites from different species of infected mosquitoes, mainly of Aedes and Culex genera. These mosquitoes are very sensitive to environmental conditions, which may determine their presence, biology, and abundance. In East Africa, RVF outbreaks are known to be closely associated with heavy rainfall events, unlike in the semi-arid regions of West Africa where the drivers of RVF emergence remain poorly understood. The assumed importance of temporary ponds and rainfall temporal distribution therefore needs to be investigated. METHODOLOGY/PRINCIPAL FINDINGS: A hydrological model is combined with a mosquito population model to predict the abundance of the two main mosquito species (Aedes vexans and Culex poicilipes involved in RVFV transmission in Senegal. The study area is an agropastoral zone located in the Ferlo Valley, characterized by a dense network of temporary water ponds which constitute mosquito breeding sites. The hydrological model uses daily rainfall as input to simulate variations of pond surface areas. The mosquito population model is mechanistic, considers both aquatic and adult stages and is driven by pond dynamics. Once validated using hydrological and entomological field data, the model was used to simulate the abundance dynamics of the two mosquito species over a 43-year period (1961-2003. We analysed the predicted dynamics of mosquito populations with regards to the years of main outbreaks. The results showed that the main RVF outbreaks occurred during years with simultaneous high abundances of both species. CONCLUSION/SIGNIFICANCE: Our study provides for the first time a mechanistic insight on RVFV transmission in West Africa. It highlights the complementary roles of Aedes vexans and Culex poicilipes mosquitoes in virus transmission, and recommends

  1. Reservoir inflow forecasting with a modified coactive neuro-fuzzy inference system: a case study for a semi-arid region

    Science.gov (United States)

    Allawi, Mohammed Falah; Jaafar, Othman; Mohamad Hamzah, Firdaus; Mohd, Nuruol Syuhadaa; Deo, Ravinesh C.; El-Shafie, Ahmed

    2017-10-01

    Existing forecast models applied for reservoir inflow forecasting encounter several drawbacks, due to the difficulty of the underlying mathematical procedures being to cope with and to mimic the naturalization and stochasticity of the inflow data patterns. In this study, appropriate adjustments to the conventional coactive neuro-fuzzy inference system (CANFIS) method are proposed to improve the mathematical procedure, thus enabling a better detection of the high nonlinearity patterns found in the reservoir inflow training data. This modification includes the updating of the back propagation algorithm, leading to a consequent update of the membership rules and the induction of the centre-weighted set rather than the global weighted set used in feature extraction. The modification also aids in constructing an integrated model that is able to not only detect the nonlinearity in the training data but also the wide range of features within the training data records used to simulate the forecasting model. To demonstrate the model's efficacy, the proposed CANFIS method has been applied to forecast monthly inflow data at Aswan High Dam (AHD), located in southern Egypt. Comparative analyses of the forecasting skill of the modified CANFIS and the conventional ANFIS model are carried out with statistical score indicators to assess the reliability of the developed method. The statistical metrics support the better performance of the developed CANFIS model, which significantly outperforms the ANFIS model to attain a low relative error value (23%), mean absolute error (1.4 BCM month-1), root mean square error (1.14 BCM month-1), and a relative large coefficient of determination (0.94). The present study ascertains the better utility of the modified CANFIS model in respect to the traditional ANFIS model applied in reservoir inflow forecasting for a semi-arid region.

  2. Managing Environmental Flows for Impounded Rivers in Semi-Arid Regions- A Habitat Suitability Index (HSI) Approach for the Assessment of River Habitat for Salmonid Populations

    Science.gov (United States)

    Pai, H.; Sivakumaran, K.; Villamizar, S. R.; Flanagan, J.; Guo, Q.; Harmon, T. C.

    2013-12-01

    Balancing ecosystem health in water-scarce, agriculturally dominated river basins remains a challenge. In dry water years, maintaining conditions for restored and sustained indigenous fish populations (a frequently used indicator for ecosystem health) is particularly challenging. Competing human demands include urban and agricultural water supplies, hydropower, and flood control. In many semi-arid regions, increasing drought intensity and frequency under future climate scenarios will combine with population increases to water scarcity. The goal of this work is to better understand how reservoir releases affect fish habitat and overall river aquatic ecosystem quality. Models integrating a diverse array of physical and biological processes and system state are used to forecast the river ecosystem response to changing drivers. We propose a distributed parameter-based Habitat Suitability Index (HSI) approach for assessing fish habitat quality. Our river ecosystem HSI maps are based on a combination of the following: (1) In situ data describing stream flow and water quality conditions; (2) Spatial observations, including surveyed cross-sections, aerial imagery and digital elevation maps (DEM) of the river and its riparian corridor; and (3) Simulated spatially distributed water depths, flow velocities, and temperatures estimated from 1D and 2D river flow and temperature models (HEC-RAS and CE-QUAL-W2, respectively). With respect to (2), image processing schemes are used to classify and map key habitat features, namely riparian edge and shallow underwater vegetation. HSI maps can be modified temporally to address specific life cycle requirements of indicator fish species. Results are presented for several reaches associated with the San Joaquin River Restoration Project, focusing on several components of the Chinook salmon life cycle. HSI maps and interpretations are presented in the context of a range of prescribed reservoir release hydrographs linked to California water

  3. Improving estimates of water resources in a semi-arid region by assimilating GRACE data into the PCR-GLOBWB hydrological model

    Science.gov (United States)

    Tangdamrongsub, Natthachet; Steele-Dunne, Susan C.; Gunter, Brian C.; Ditmar, Pavel G.; Sutanudjaja, Edwin H.; Sun, Yu; Xia, Ting; Wang, Zhongjing

    2017-04-01

    An accurate estimation of water resources dynamics is crucial for proper management of both agriculture and the local ecology, particularly in semi-arid regions. Imperfections in model physics, uncertainties in model land parameters and meteorological data, as well as the human impact on land changes often limit the accuracy of hydrological models in estimating water storages. To mitigate this problem, this study investigated the assimilation of terrestrial water storage variation (TWSV) estimates derived from the Gravity Recovery And Climate Experiment (GRACE) data using an ensemble Kalman filter (EnKF) approach. The region considered was the Hexi Corridor in northern China. The hydrological model used for the analysis was PCR-GLOBWB, driven by satellite-based forcing data from April 2002 to December 2010. The impact of the GRACE data assimilation (DA) scheme was evaluated in terms of the TWSV, as well as the variation of individual hydrological storage estimates. The capability of GRACE DA to adjust the storage level was apparent not only for the entire TWSV but also for the groundwater component. In this study, spatially correlated errors in GRACE data were taken into account, utilizing the full error variance-covariance matrices provided as a part of the GRACE data product. The benefits of this approach were demonstrated by comparing the EnKF results obtained with and without taking into account error correlations. The results were validated against in situ groundwater data from five well sites. On average, the experiments showed that GRACE DA improved the accuracy of groundwater storage estimates by as much as 25 %. The inclusion of error correlations provided an equal or greater improvement in the estimates. In contrast, a validation against in situ streamflow data from two river gauges showed no significant benefits of GRACE DA. This is likely due to the limited spatial and temporal resolution of GRACE observations. Finally, results of the GRACE DA study

  4. Hydrogeochemical evaluation of conventional and hot dry rock geothermal resource potential in the Clear Lake region, California

    Energy Technology Data Exchange (ETDEWEB)

    Goff, F.; Adams, A.I.; Trujillo, P.E.; Counce, D.

    1993-05-01

    Chemistry, stable isotope, and tritium contents of thermal/mineral waters in the Clear Lake region were used to evaluate conventional and hot dry rock (HDR) geothermal potential for electrical generation. Thermal/mineral waters of the Clear Lake region are broadly classified as thermal meteoric and connate types based on chemical and isotopic criteria. Ratios of conservative components such as B/Cl are extremely different among all thermal/mineral waters of the Clear Lake region except for clusters of waters emerging from specific areas such as the Wilbur Springs district and the Agricultural Park area south of Mt. Konocti. In contrast ratios of conservative components in large, homogeneous geothermal reservoirs are constant. Stable isotope values of Clear Lake region waters show a mixing trend between thermal meteoric and connate (generic) end-members. The latter end-member has enriched {delta}D as well as enriched {delta}{sup 18}O, from typical high-temperature geothermal reservoir waters. Tritium data indicate most Clear Lake region waters are mixtures of old and young fluid components. Subsurface equilibration temperature of most thermal/mineral waters of the Clear Lake region is {le}150{degree}C based on chemical geothermometers but it is recognized that Clear Lake region waters are not typical geothermal fluids and that they violate rules of application of many geothermometers. The combined data indicate that no large geothermal reservoir underlies the Clear Lake region and that small localized reservoirs have equilibration temperatures {le}150{degree}C (except for Sulphur Bank mine). HDR technologies are probably the best way to commercially exploit the known high-temperatures existing beneath the Clear Lake region particularly within and near the main Clear Lake volcanic field.

  5. Interannual variability of a precipitation gradient along the semi-arid catchment areas for the metropolitan region of Lima- Peru in relation to atmospheric circulation at the mesoscale

    Science.gov (United States)

    Otto, Marco; Seidel, Jochen; Trachte, Katja

    2013-04-01

    following questions. How is the interannual variability of the observed precipitation gradient related to atmospheric circulation east (Amazon basin) and west (south-east Pacific) of the study region? If those relations are quantifiable, are there any forecast potentials for the characteristics of the precipitation gradient during the raining season? The results of the study provide valuable information needed to understand the generation of rainfall in the frame of a case study for the largest metropolitan area that is located at the arid Pacific coast of Peru. This information may also be useful for local managers in order to optimise water resource management and land use strategies.

  6. Stoichiometry of water-soluble ions in PM2.5: Application in source apportionment for a typical industrial city in semi-arid region, Northwest China

    Science.gov (United States)

    Zhou, Haijun; Lü, Changwei; He, Jiang; Gao, Manshu; Zhao, Boyi; Ren, Limin; Zhang, Lijun; Fan, Qingyun; Liu, Tao; He, Zhongxiang; Dudagula; Zhou, Bin; Liu, Hualin; Zhang, Yu

    2018-05-01

    Water-soluble ions (WSIs) are major components of PM2.5 and it is valuable for understanding physical and chemical characteristics, sources, behaviors and formation mechanism of WSIs. Baotou is a traditionally industrial city in semi-arid region and frequently subjected to dust storms from March to May. In recent years, air pollution has been listed as one of the most important environmental problems in Baotou. To investigate the seasonal variations and sources of WSIs in PM2.5, the WSIs including SO42-, NO3-, Cl-, F-, NH4+, K+, Na+, Ca2+ and Mg2+ were monitored at six urban sites in Baotou. The results showed that high concentrations of Ca2+ and Na+ were found responding to dust storm events, while high concentrations of SO42-, NO3-, NH4+, K+ and Cl- were observed during haze days. The correlations analysis indicated that excess sulfuric and nitric acid was likely neutralized by carbonate minerals such as calcite, aragonite and dolomite in normal days and cations were fully neutralized during all the sampling periods, while cations were excessive in dust storm days. The concentrations of [NH4+ + SO42- + NO3-], [Na+ + Ca2+ + Mg2+] and [Cl- + K+ + F-] indicated the northwest and southeast region of Baotou presented comparatively high contributions of secondary aerosol and crustal dust, respectively, which were mainly related to the industrial distribution and urbanization process. The cluster analysis, ternary diagram and principal component analysis have a good agreement in source apportionment, where crustal dust sources, secondary aerosol source and the mixture of coal combustion, biomass burning and industrial pollution sources were the main sources of WSIs in PM2.5. The seasonal pattern of sulfur oxidation ratio (SOR) was September > April > November > January, while the nitrogen oxidation ratio (NOR) April > January > November > September in Baotou. This work evaluated the seasonal variation, distribution and source of WSIs on the basis of its stoichiometry in

  7. Temporal and elevation trends in rainfall erosivity on a 149 km2 watershed in a semi-arid region of the American Southwest

    Directory of Open Access Journals (Sweden)

    Mark A. Nearing

    2015-06-01

    Full Text Available Temporal changes in rainfall erosivity can be expected to occur with changing climate, and because rainfall amounts are known to be in part of a function of elevation, erosivity can be expected to be influenced by elevation as well. This is particularly true in mountainous regions such as are found over much of the western United States. The objective of this study was to identify temporal and elevation trends in rainfall erosivity on a 149 km2 (58 miles2 watershed in a semi-arid region of southeastern Arizona. Data from 84 rain gages for the years 1960–2012 at elevations ranging from 1231 to 1644 m (4038–5394 ft were used in the analyses. The average annual erosivity over the watershed as a whole was 1104 MJ mm ha−1 h−1 yr−1 (65 hundreds of foot ton inch acre−1 h−1 yr−1, and ranged from approximately 950 to 1225 MJ mm ha−1 h−1 yr−1 (56–72 hundreds of foot ton inch acre−1 h−1 yr−1, with a statistical trend showing greater erosivity at the higher elevations. No statistically significant temporal changes in annual or summer erosivities were found. This result stands in contrast to recent modeling studies of runoff and erosion in the area based on downscaled GCM information that project significant levels of erosivity changes over coming decades. These results are consistent with known orographic rainfall effects, but contrast with recent studies that presented projections of significant trends of increasing erosivity in the future based on downscaled GCM outputs for the area. The results illustrate the need for testing and developing improved techniques to evaluate future erosion scenarios for purposes of making targeted soil conservation decisions. Keywords: Climate change, R-factor, RUSLE, Semiarid, Soil erosion, Walnut Gulch

  8. A regional field-based assessment of organic C sequestration and GHG balances in irrigated agriculture in Mediterranean semi-arid land

    Science.gov (United States)

    Virto, Inigo; Antón, Rodrigo; Arias, Nerea; Orcaray, Luis; Enrique, Alberto; Bescansa, Paloma

    2016-04-01

    In a context of global change and increasing food demand, agriculture faces the challenge of ensuring food security making a sustainable use of resources, especially arable land and water. This implies in many areas a transition towards agricultural systems with increased and stable productivity and a more efficient use of inputs. The introduction of irrigation is, within this framework, a widespread strategy. However, the C cycle and the net GHG emissions can be significantly affected by irrigation. The net effect of this change needs to be quantified at a regional scale. In the region of Navarra (NE Spain) more than 22,300 ha of rainfed agricultural land have been converted to irrigation in the last years, adding to the previous existing irrigated area of 70,000 ha. In this framework the project Life+ Regadiox (LIFE12 ENV/ES/000426, http://life-regadiox.es/) has the objective of evaluating the net GHG balances and atmospheric CO2 fixation rates of different management strategies in irrigated agriculture in the region. The project involved the identification of areas representative of the different pedocllimatic conditions in the region. This required soil and climate characterizations, and the design of a network of agricultural fields representative of the most common dryland and irrigation managements in these areas. This was done from available public datasets on climate and soil, and from soil pits especially sampled for this study. Two areas were then delimited, mostly based on their degree of aridity. Within each of those areas, fields were selected to allow for comparisons at three levels: (i) dryland vs irrigation, (ii) soil and crop management systems for non-permanent crops, and (iii) soil management strategies for permanent crops (namely olive orchards and vineyards). In a second step, the objective of this work was to quantify net SOC variations and GHG balances corresponding to the different managements identified in the previous step. These

  9. Applying spatial analysis techniques to assess the suitability of multipurpose uses of spring water in the Jiaosi Hot Spring Region, Taiwan

    Science.gov (United States)

    Jang, Cheng-Shin

    2016-04-01

    The Jiaosi Hot Spring Region is located in northeastern Taiwan and is rich in geothermal springs. The geothermal development of the Jiaosi Hot Spring Region dates back to the 18th century and currently, the spring water is processed for various uses, including irrigation, aquaculture, swimming, bathing, foot spas, and recreational tourism. Because of the proximity of the Jiaosi Hot Spring Region to the metropolitan area of Taipei City, the hot spring resources in this region attract millions of tourists annually. Recently, the Taiwan government is paying more attention to surveying the spring water temperatures in the Jiaosi Hot Spring Region because of the severe spring water overexploitation, causing a significant decline in spring water temperatures. Furthermore, the temperature of spring water is a reliable indicator for exploring the occurrence and evolution of springs and strongly affects hydrochemical reactions, components, and magnitudes. The multipurpose uses of spring water can be dictated by the temperature of the water. Therefore, accurately estimating the temperature distribution of the spring water is critical in the Jiaosi Hot Spring Region to facilitate the sustainable development and management of the multipurpose uses of the hot spring resources. To evaluate the suitability of spring water for these various uses, this study spatially characterized the spring water temperatures of the Jiaosi Hot Spring Region by using ordinary kriging (OK), sequential Gaussian simulation (SGS), and geographical information system (GIS). First, variogram analyses were used to determine the spatial variability of spring water temperatures. Next, OK and SGS were adopted to model the spatial distributions and uncertainty of the spring water temperatures. Finally, the land use (i.e., agriculture, dwelling, public land, and recreation) was determined and combined with the estimated distributions of the spring water temperatures using GIS. A suitable development strategy

  10. Evaluation of Three Evaporation Estimation Techniques In A Semi-Arid Region (Omar El Mukhtar Reservoir Sluge, Libya- As a case Study

    Directory of Open Access Journals (Sweden)

    Lubna s. Ben Taher

    2017-02-01

    Full Text Available In many semi-arid countries in the world like Libya, drinking water supply is dependent on reservoirs water storage. Since the evaporation rate is very high in semi-arid countries, estimates and forecasts of reservoir evaporation rate can be useful in the management of major water source. Many researchers have been investigating the suitability of estimates evaporation rates methods in many climatic settings, infrequently of which were in an arid setting. This paper presents the modeling results of evaporation from Omar El Mukhtar Reservoir, Libya. Three techniques namely (artificial neural networks (ANN, Multiple linear regression (MLR and response surface methods (RSM were developed, to assess the estimation of monthly evaporation records from 2001 to 2009; their relative performance were compared using the coefficient of determination(E, mean absolute percentage error (MAPE%, and 95% confidence interval. The key variables used to develop and validate the models were: monthly (precipitation Rf., average temperature Temp., relative humidity Rh., sunshine hours Sh., atmospheric pressure Pa. and wind speed Ws.. The encouraging results approved that the models with more inputs generally had better accuracies and the ANN model performed superior to the other models in predicting monthly Evp with high E=0.86 and low MAPE%= 13.9 and the predicted mean within the range of observed 95CI%. In summary, it is revealed in this study that the ANN and RSM models are appropriate for predicting Evp using climatic inputs in semi-arid climate.

  11. Geochemistry of thermal/mineral waters in the Clear Lake region, California, and implications for hot dry rock geothermal development

    Energy Technology Data Exchange (ETDEWEB)

    Goff, F.; Adams, A.I.; Trujillo, P.E.; Counce, D.; Mansfield, J.

    1993-02-01

    Thermal/mineral waters of the Clear Lake region are broadly classified as thermal meteoric and connote types based on chemical and isotopic criteria. Ratios of conservative components such as B/Cl are extremely different among all thermal/mineral waters of the Clear Lake region except for clusters of waters emerging from specific areas such as the Wilbur Springs district and the Agricultural Park area south of Mt. Konocti. In contrast, ratios of conservative components in large, homogeneous geothermal reservoirs are constant. Stable isotope values of Clear Lake region waters show a mixing trend between thermal meteoric and connote end-members. The latter end-member has enriched [delta]D as well as enriched d[sup l8]O, very different from typical high-temperature geothermal reservoir waters. Tritium data and modeling of ages indicate most Clear Lake region waters are 500 to > 10,000 yr., although mixing of old and young components is implied by the data. The age of end-member connate water is probably > 10,000 yr. Subsurface equilibration temperature of most thermal/mineral waters of the Clear Lake region is [le] 150[degrees]C based on chemical geothermometers but it is recognized that Clear Lake region waters are not typical geothermal fluids and that they violate rules of application of many geothermometers. The combined data indicate that no large geothermal reservoir underlies the Clear Lake region and that small localized reservoirs have equilibration temperatures [le] 150[degrees]C (except for Sulphur Bank Mine). Hot dry rock technologies are the best way to commercially exploit the known high temperatures existing beneath the Clear Lake region, particularly within the main Clear Lake volcanic field.

  12. Archaeal and bacterial diversity in two hot spring microbial mats from a geothermal region in Romania.

    Science.gov (United States)

    Coman, Cristian; Drugă, Bogdan; Hegedus, Adriana; Sicora, Cosmin; Dragoş, Nicolae

    2013-05-01

    The diversity of archaea and bacteria was investigated in two slightly alkaline, mesophilic hot springs from the Western Plain of Romania. Phylogenetic analysis showed a low diversity of Archaea, only three Euryarchaeota taxa being detected: Methanomethylovorans thermophila, Methanomassiliicoccus luminyensis and Methanococcus aeolicus. Twelve major bacterial groups were identified, both springs being dominated by Cyanobacteria, Chloroflexi and Proteobacteria. While at the phylum/class-level the microbial mats share a similar biodiversity; at the species level the geothermal springs investigated seem to be colonized by specific consortia. The dominant taxa were filamentous heterocyst-containing Fischerella, at 45 °C and non-heterocyst Leptolyngbya and Geitlerinema, at 55 °C. Other bacterial taxa (Thauera sp., Methyloversatilis universalis, Pannonibacter phragmitetus, Polymorphum gilvum, Metallibacterium sp. and Spartobacteria) were observed for the first time in association with a geothermal habitat. Based on their bacterial diversity the two mats were clustered together with other similar habitats from Europe and part of Asia, most likely the water temperature playing a major role in the formation of specific microbial communities that colonize the investigated thermal springs.

  13. Bacterial and archaeal diversity in two hot spring microbial mats from the geothermal region of Tengchong, China.

    Science.gov (United States)

    Pagaling, Eulyn; Grant, William D; Cowan, Don A; Jones, Brian E; Ma, Yanhe; Ventosa, Antonio; Heaphy, Shaun

    2012-07-01

    We investigated the bacterial and archaeal diversity in two hot spring microbial mats from the geothermal region of Tengchong in the Yunnan Province, China, using direct molecular analyses. The Langpu (LP) laminated mat was found by the side of a boiling pool with temperature of 60-65 °C and a pH of 8.5, while the Tengchong (TC) streamer mat consisted of white streamers in a slightly acidic (pH 6.5) hot pool outflow with a temperature of 72 °C. Four 16S rRNA gene clone libraries were constructed and restriction enzyme analysis of the inserts was used to identify unique sequences and clone frequencies. From almost 200 clones screened, 55 unique sequences were retrieved. Phylogenetic analysis showed that the LP mat consisted of a diverse bacterial population [Cyanobacteria, Chloroflexi, Chlorobia, Nitrospirae, 'Deinococcus-Thermus', Proteobacteria (alpha, beta and delta subdivisions), Firmicutes, Bacteroidetes and Actinobacteria], while the archaeal population was dominated by methanogenic Euryarchaeota and Crenarchaeota. In contrast, the TC streamer mat consisted of a bacterial population dominated by Aquificae, while the archaeal population also contained Korarchaeota as well as Crenarchaeota and methanogenic Euryarchaeota. These mats harboured clone sequences affiliated to unidentified lineages, suggesting that they are a potential source for discovering novel bacteria and archaea.

  14. Thermal comfort requirements in hot dry regions with special reference to Riyadh Part 2: for Friday prayer

    Energy Technology Data Exchange (ETDEWEB)

    Saeed, S.A.R. [King Saud University, Riyadh (Saudi Arabia). Dept. of Architecture and Building Science

    1996-01-01

    This study is an attempt to define thermal comfort requirements for Friday prayer during the hot season of Riyadh, Saudi Arabia. According to Islam, a Muslim should perform his prayers five times a day. The obligatory five prayers are Subuh prayer immediately before dawn, Thohor prayer in the afternoon, Assor prayer in late afternoon, Maghreb prayer immediately after sunset, and Ishaa prayer early evening. Generally, Muslims are encouraged to perform all five prayers in a mosque. Friday prayer that replaces Thohor prayer once a week, should take place in one of the main mosques of the neighbourhood. The mosque where Friday prayer could be performed is known as Friday mosque. Usually Friday prayer is attended by hundreds of worshippers and takes place in the afternoon. Since the summer of Riyadh is characterised by a very high temperature and a very low relative humidity, the indoor climate of the Friday mosque (Al-Masjed Al-Gamae) need a special study. This is the second part of a series of field investigations dealing with thermal comfort requirements in the hot-dry region of Saudi Arabia. (author)

  15. Larvicidal potential of wild mustard (Cleome viscosa) and gokhru (Tribulus terrestris) against mosquito vectors in the semi-arid region of Western Rajasthan.

    Science.gov (United States)

    Bansal, S K; Singh, Karam V; Sharma, Sapna

    2014-03-01

    effective as compared to the fruit extracts of T. terrestris indicating that active larvicidal principle may be present in the fruits of this plant species. The studywould be of great importance while formulating the control strategy, for vectors of malaria, dengue and lymphatic filariasis, based on alternative plant based insecticides in this semi-arid region.

  16. Effect of composts on microbial dynamics and activity, dry root rot severity and seed yield of cowpea in the Indian arid region

    Directory of Open Access Journals (Sweden)

    Meenu BAREJA

    2011-01-01

    Full Text Available Nutrient-deficient sandy soil, having poor moisture retention, favors  Macrophomina phaseolina, a soil-borne plant pathogen, occurring in severe form on many important crops grown in the Indian arid region. In a 2-year field experiment, five composts (4 ton/ha prepared from residues of Calotropis procera, Prosopis juliflora, Azadirachta indica, Acacia nilotica, and on-farm weeds were tested on cowpea (Vigna unguiculata to determine their effectiveness in limiting the  severity of charcoal rot caused by M. phaseolina in relation to the microbial population dynamics, microbial activity and the seed yield of cowpea.  In general, compost-amended plots retained 8.9% higher moisture than unamended plots. The microbial population increased in amended plots during the crop season. Populations of total fungi and actinomycetes were heighest in Calotropis compost-amended soil, while total bacteria were maximum in weed- compost amended soil. Microbial activity in amended plots was  26.3% higher than in unamended plots. Among trace elements,  uptake of Zn, Mn, Fe and Cu was  heighest  in plants grown in weed-compost amended soil followed by A. nilotica compost-amended soil. Soil amendment with the composts significantly reduced  plant mortality due to charcoal rot. The lowest mortality was recorded in plants amended with A. nilotica compost (5.5% followed by P. juliflora compost (5.8, while the  highest plant mortality (11.5% from charcoal rot occurred in the unamended control on the basis of the pooled average of two years. There was a significant inverse correlation between microbial activity and charcoal rot incidence in cowpea at 20 days after planting. Composts also had a beneficial effect on yield, with a 28.3% increase in seed yield in P. juliflora compost-amended plots. These results suggest that in resource-deficient farming , certain on-farm wastes can be effectively utilized for managing soil-borne pathogens, as well as  for

  17. Outdoor thermal comfort characteristics in the hot and humid region from a gender perspective.

    Science.gov (United States)

    Tung, Chien-Hung; Chen, Chen-Peng; Tsai, Kang-Ting; Kántor, Noémi; Hwang, Ruey-Lung; Matzarakis, Andreas; Lin, Tzu-Ping

    2014-11-01

    Thermal comfort is a subjective psychological perception of people based also on physiological thermoregulation mechanisms when the human body is exposed to a combination of various environmental factors including air temperature, air humidity, wind speed, and radiation conditions. Due to the importance of gender in the issue of outdoor thermal comfort, this study compared and examined the thermal comfort-related differences between male and female subjects using previous data from Taiwanese questionnaire survey. Compared with males, the results indicated that females in Taiwan are less tolerant to hot conditions and intensely protect themselves from sun exposure. Our analytical results are inconsistent with the findings of previous physiological studies concerning thermal comfort indicating that females have superior thermal physiological tolerance than males. On the contrary, our findings can be interpreted on psychological level. Environmental behavioral learning theory was adopted in this study to elucidate this observed contradiction between the autonomic thermal physiological and psychological-behavioral aspects. Women might desire for a light skin tone through social learning processes, such as observation and education, which is subsequently reflected in their psychological perceptions (fears of heat and sun exposure) and behavioral adjustments (carrying umbrellas or searching for shade). Hence, these unique psychological and behavioral phenomena cannot be directly explained by autonomic physiological thermoregulation mechanisms. The findings of this study serve as a reference for designing spaces that accommodates gender-specific thermal comfort characteristics. Recommendations include providing additional suitable sheltered areas in open areas, such as city squares and parks, to satisfy the thermal comfort needs of females.

  18. Experimental investigation on the thermal properties of hydrogen jet flame and hot currents in the downstream region

    Energy Technology Data Exchange (ETDEWEB)

    Imamura, Tomohiko; Mogi, Toshio; Wada, Yuji; Horiguchi, Sadashige [Research Core for Explosion Safety, National Institute of Advanced Industrial Science and Technology (AIST), 16-1 Onogawa, Tsukuba, Ibaraki 305-8569 (Japan); Hamada, Shota; Miyake, Atsumi; Ogawa, Terushige [Graduate School of Environment and Information Sciences, Yokohama National University, 79-7 Tokiwadai, Hodogaya-ku, Yokohama 240-8501 (Japan)

    2008-07-15

    A series of experiments were conducted to understand the thermal hazards of hydrogen jet flames. In particular, we focused on the temperature properties of hot currents in the downstream region, because it was expected that this involved the most serious thermal hazards. The flame length and width depended on the nozzle diameter and the spouting pressure, namely, the mass flow rate, with similar dependences that were reported by other researchers. The temperature rise from ambient air along the trajectory depended on the balance of the flame length and the traveling distance from the flame tip. The position of the trajectory depended not only on the balance of flame length and the traveling distance, but also on the horizontal momentum induced by the spouting pressure. Empirical formulae for predicting the position and temperature rise of the trajectory were developed by the flame length, traveling distance, spouting pressure, and nozzle diameter as variables. (author)

  19. Flavor Oscillations in the Supernova Hot Bubble Region: Nonlinear Effects of Neutrino Background

    Science.gov (United States)

    Pastor, Sergio; Raffelt, Georg

    2002-10-01

    The neutrino flux close to a supernova core contributes substantially to neutrino refraction so that flavor oscillations become a nonlinear phenomenon. One unexpected consequence is efficient flavor transformation for antineutrinos in a region where only neutrinos encounter a Mikheyev-Smirnov-Wolfenstein resonance or vice versa. Contrary to previous studies we find that in the neutrino-driven wind the electron fraction Ye always stays below 0.5, corresponding to a neutron-rich environment as required by r-process nucleosynthesis. The relevant range of masses and mixing angles includes the region indicated by LSND, but not the atmospheric or solar oscillation parameters.

  20. Improvement in remote sensing of low vegetation cover in arid regions by correcting vegetation indices for soil ''noise''

    International Nuclear Information System (INIS)

    Escadafal, R.; Huete, A.

    1991-01-01

    The variations of near-infrared red reflectance ratios of ten aridic soil samples were correlated with a ''redness index'' computed from red and green spectral bands. These variations have been shown to limit the performances of vegetation indices (NDVI and SAVI) in discriminating low vegetation covers. The redness index is used to adjust for this ''soil noise''. Dala simulated for vegetation densities of 5 to 15% cover showed that the sensitivity of the corrected vegetation indices was significantly improved. Specifically, the ''noise-corrected'' SAVI was able to assess vegetation amounts with an error four times smaller than the uncorrected NDVI. These promising results should lead to a significant improvement in assessing biomass in arid lands from remotely sensed data. (author) [fr

  1. Unveiling the Hot Molecular Core in the Ultracompact H II Region with Extended Emission G12.21-0.10

    Science.gov (United States)

    de la Fuente, E.; Trinidad, M. A.; Porras, A.; Rodríguez-Rico, C.; Araya, E. D.; Kurtz, S.; Hofner, P.; Nigoche-Netro, A.

    2018-04-01

    We present a multiwavelength study of the cometary H II region G12.21-0.10 using the VLA and OVRO. Both radio continuum (0.3, 0.7, 2 and 3.6 cm) and spectral lines of H41α, 13CS(2-1) & (1-0), and NH3(2,2) & (4,4) observations are included. We find two 3 mm continuum peaks toward G12.21-0.10; one of them is spatially coincident with the UC H II region, while the other coincides spatially with a molecular clump. We also find that the 0.7, 2 and 3.6 cm continuum and H41α line are only detected toward the UC H II region, while the 13CS, and NH3 are spatially associated with the molecular clump. Based on the morphology, kinetic temperature (≍86 K), volumetric density (≍1.5×106 cm-3) and linear size (≍0.22 pc) of the molecular clump, we suggest this source is consistent with a hot molecular core.

  2. Hot regions of labile and stable soil organic carbon in Germany - Spatial variability and driving factors

    Science.gov (United States)

    Vos, Cora; Jaconi, Angélica; Jacobs, Anna; Don, Axel

    2018-06-01

    Atmospheric carbon dioxide levels can be mitigated by sequestering carbon in the soil. Sequestration can be facilitated by agricultural management, but its influence is not the same on all soil carbon pools, as labile pools with a high turnover may be accumulated much faster but are also more vulnerable to losses. The aims of this study were to (1) assess how soil organic carbon (SOC) is distributed among SOC fractions on a national scale in Germany, (2) identify factors influencing this distribution and (3) identify regions with high vulnerability to SOC losses. The SOC content and proportion of two different SOC fractions were estimated for more than 2500 mineral topsoils (soil texture, bulk soil C / N ratio, total SOC content and pH. For some regions, the drivers were linked to the land-use history of the sites. Arable topsoils in central and southern Germany were found to contain the highest proportions and contents of stable SOC fractions, and therefore have the lowest vulnerability to SOC losses. North-western Germany contains an area of sandy soils with unusually high SOC contents and high proportions of light SOC fractions, which are commonly regarded as representing a labile carbon pool. This is true for the former peat soils in this area, which have already lost and are at high risk of losing high proportions of their SOC stocks. Those black sands can, however, also contain high amounts of stable SOC due to former heathland vegetation and need to be treated and discussed separately from non-black sand agricultural soils. Overall, it was estimated that, in large areas all over Germany, over 30 % of SOC is stored in easily mineralisable forms. Thus, SOC-conserving management of arable soils in these regions is of great importance.

  3. Spitzer Observations of M33 & M83 and the Hot Star, Hii Region Connection

    Science.gov (United States)

    Rubin, R.; Simpson, J.; Colgan, S.; Dufour, R.; Citron, R.; Ray, K.; Erickson, E.; Haas, M.; Pauldrach, A.

    2007-05-01

    H II regions play a crucial role in the measurement of current interstellar abundances. They also serve as laboratories for atomic physics and provide fundamental data about heavy element abundances that serve to constrain models of galactic chemical evolution. We observed emission lines of [S IV] 10.5, H (7-6) 12.4, [Ne II] 12.8, [Ne III] 15.6, & [S III] 18.7 micron cospatially with the Spitzer Space Telescope using the Infrared Spectrograph (IRS) in short-high mode (SH). Here we concentrate on the galaxy M33 and compare the results with our earlier similar study of M83. In each of these substantially face-on spirals, we observed ˜25 H II regions, covering a full range of galactocentric radii (RG). For most of the M33 H II regions, we were able to measure the H (7-6) line while none were detectable in M83. This limited our M83 study to a determination of the Ne++/Ne+, /, and S3+/S++ abundance ratios vs. RG. Angular brackets denote fractional ionizations. As well as having the addition of fluxes for the H(7-6) line, the M33 H II regions are generally of much higher ionization than those in M83, resulting in larger Ne++/Ne+ and S3+/ S++ abundance ratios. For M33, in addition to what we derived for those nebulae in M83, we are also able to derive Ne/H, S/H and Ne/S vs. RG. Important advantages compared with prior optical studies are: 1) the IR lines have a weak and similar electron temperature (Te) dependence while optical lines vary exponentially with Te and 2) the IR lines suffer far less from interstellar extinction. Additionally, these data may be used as constraints on the ionizing spectral energy distribution for the stars exciting these nebulae by comparing the above ionic ratios with predictions using stellar atmosphere models from several different non-LTE model sets. This work is based on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory, California Institute of Technology under NASA contract 1407

  4. GIANT H II REGIONS IN M101. I. X-RAY ANALYSIS OF HOT GAS

    International Nuclear Information System (INIS)

    Sun Wei; Chen Yang; Feng Li; Chu, You-Hua; Chen, C.-H. Rosie; Wang, Q. Daniel; Li Jiangtao

    2012-01-01

    We performed a Chandra X-ray study of three giant H II regions (GHRs), NGC 5461, NGC 5462, and NGC 5471, in the spiral galaxy M101. The X-ray spectra of the three GHRs all contain a prominent thermal component with a temperature of ∼0.2 keV. In NGC 5461, the spatial distribution of the soft ( 52 erg, is consistent with a hypernova origin. In addition, a bright source in the field of NGC 5462 has been identified as a background active galactic nucleus, instead of a black hole X-ray binary in M101.

  5. The C-terminus hot spot region helps in the fibril formation of bacteriophage-associated hyaluronate lyase (HylP2).

    Science.gov (United States)

    Shukla, Harish; Singh, Sudhir Kumar; Singh, Amit Kumar; Mitra, Kalyan; Akhtar, Md Sohail

    2015-09-23

    The bacteriophage encoded hyaluronate lyases (HylP and HylP2) degrade hyaluronan and other glycosaminoglycans. HylP2 forms a functional fibril under acidic conditions in which its N-terminus is proposed to form the fibrillar core, leading to nucleation and acceleration of fibril formation. Here we report the presence of a hot spot region (A144GVVVY149) towards the carboxy terminus of HylP2, essential for the acceleration of fibril formation. The 'hot spot' is observed to be inherently mutated for valines (A178AMVMY183) in case of HylP. The N- terminal swapped chimeras between these phage HLs ((N)HylP2(C)HylP and (N)HylP(C)HylP2) or HylP did not form fibrils at acidic pH. However, seeding of prefibrils of HylP2 recompensed nucleation and led to fibrillation in (N)HylP(C)HylP2. The V147A mutation in the 'hot spot' region abolished fibril formation in HylP2. The M179V and M181V double mutations in the 'hot spot' region of HylP led to fibrillation with the seeding of prefibrils. It appears that fibrillation in HylP2 even though is initiated by the N-terminus, is accelerated by the conserved 'hot spot' region in the C-terminus. A collagenous (Gly-X-Y)10 motif in the N-terminus and a mutated 'hot spot' region in the C-terminus of HylP affect fibrillar nucleation and acceleration respectively.

  6. Arid Green Infrastructure for Water Control and Conservation ...

    Science.gov (United States)

    Green infrastructure is an approach to managing wet weather flows using systems and practices that mimic natural processes. It is designed to manage stormwater as close to its source as possible and protect the quality of receiving waters. Although most green infrastructure practices were first developed in temperate climates, green infrastructure also can be a cost-effective approach to stormwater management and water conservation in arid and semi-arid regions, such as those found in the western and southwestern United States. Green infrastructure practices can be applied at the site, neighborhood and watershed scales. In addition to water management and conservation, implementing green infrastructure confers many social and economic benefits and can address issues of environmental justice. The U.S. Environmental Protection Agency (EPA) commissioned a literature review to identify the state-of-the science practices dealing with water control and conservation in arid and semi-arid regions, with emphasis on these regions in the United States. The search focused on stormwater control measures or practices that slow, capture, treat, infiltrate and/or store runoff at its source (i.e., green infrastructure). The material in Chapters 1 through 3 provides background to EPA’s current activities related to the application of green infrastructure practices in arid and semi-arid regions. An introduction to the topic of green infrastructure in arid and semi-arid regions i

  7. Assessing gendered roles in water decision-making in semi-arid regions through sex-disaggregated water data with UNESCO-WWAP gender toolkit

    Science.gov (United States)

    Miletto, Michela; Greco, Francesca; Belfiore, Elena

    2017-04-01

    . Extreme climatic events like floods and droughts could severely impact the status of water resources and dependent ecosystems and the sustainability of household activities and local economies, given the absence of gender sensitive preparedness to hydrological and meteorological extremes. This paper describes the application of the WWAP Gender Toolkit to water data assessments in semi-arid region of the Stampriet transboundary aquifer shared by Botwana, Namibia and South Africa, in the framework of the "Groundwater Resources Governance in Transboundary Aquifers" - GGRETA project, led and executed by the UNESCO International Hydrological Programme (IHP), and financed by the Swiss Agency for Development and Cooperation (SDC). The tests in the field proved the reliability of WWAP gender toolkit and selected gender-sensitive indicators in the freshwater assessment. Further analysis could inform on the gaps and needs for climate adaptation practices. Field data identified socially-determined differences in roles, and confirmed the prevalent role of women in managing freshwater for drinking and sanitation purposes within the household boundaries, while decision-making for water allocation and use (with implications on hydrological risk) for agriculture and livestock purposes, is broadly under men's responsibility.

  8. Performance evaluation of constructed wetlands: A review of arid ...

    African Journals Online (AJOL)

    Aiming at environmental pollution control through the use of constructed wetlands systems (CWs) in arid and semi arid climatic region, a detailed review of CWs was undertaken. Given the practical application and simplicity of the technology, principles for building phytotechnology-ecohydrology environment used for ...

  9. Watershed Management in Arid Zones: A Prototype Short Course.

    Science.gov (United States)

    Thames, John L., Ed.; Fischer, John N., Ed.

    Presented is information recommended for inclusion in a short course to help extend knowledge of water resource development and research techniques in arid and semi-arid regions. Information is particularly intended for applicability in developing nations. Included are considerations of livestock grazing, use of hydrologic data, vegetation…

  10. A Look into the Melting Pot: The mecC-Harboring Region Is a Recombination Hot Spot in Staphylococcus stepanovicii.

    Directory of Open Access Journals (Sweden)

    Torsten Semmler

    Full Text Available Horizontal gene transfer (HGT is an important driver for resistance- and virulence factor accumulation in pathogenic bacteria such as Staphylococcus aureus.Here, we have investigated the downstream region of the bacterial chromosomal attachment site (attB for the staphylococcal cassette chromosome mec (SCCmec element of a commensal mecC-positive Staphylococcus stepanovicii strain (IMT28705; ODD4 with respect to genetic composition and indications of HGT. S. stepanovicii IMT28705 was isolated from a fecal sample of a trapped wild bank vole (Myodes glareolus during a screening study (National Network on "Rodent-Borne Pathogens" in Germany. Whole genome sequencing (WGS of IMT28705 together with the mecC-negative type strain CM7717 was conducted in order to comparatively investigate the genomic region downstream of attB (GenBank accession no. KR732654 and KR732653.The bank vole isolate (IMT28705 harbors a mecC gene which shares 99.2% nucleotide (and 98.5% amino acid sequence identity with mecC of MRSA_LGA251. In addition, the mecC-encoding region harbors the typical blaZ-mecC-mecR1-mecI structure, corresponding with the class E mec complex. While the sequences downstream of attB in both S. stepanovicii isolates (IMT28705 and CM7717 are partitioned by 15 bp direct repeats, further comparison revealed a remarkable low concordance of gene content, indicating a chromosomal "hot spot" for foreign DNA integration and exchange.Our data highlight the necessity for further research on transmission routes of resistance encoding factors from the environmental and wildlife resistome.

  11. Cyanobacterial ecotypes in different optical microenvironments of a 68 C hot spring mat community revealed by 16S-23S rRNA internal transcribed spacer region variation

    DEFF Research Database (Denmark)

    Ferris, Mike J.; Kühl, Michael; Wieland, Andrea

    2003-01-01

    We examined the population of unicellular cyanobacteria (Synechococcus) in the upper 3-mm vertical interval of a 68°C region of a microbial mat in a hot spring effluent channel (Yellowstone National Park, Wyoming). Fluorescence microscopy and microsensor measurements of O2 and oxygenic photosynth...

  12. Laser-fluorescence determination of trace uranium in hot spring water, geothermal water and tap water in Xi'an Lishan region

    International Nuclear Information System (INIS)

    Ma Wenyan; Zhou Chunlin; Han Feng; Di Yuming

    2002-01-01

    Using the Laser-Fluorescence technique, an investigation was made, adopting the standard mix method, on trace uranium concentrations in hot spring water and geothermal water from Lishan region, and in tap water from some major cities in Shanxi province. Totally 40 samples from 27 sites were investigated. Measurement showed that the tap water contains around 10 -6 g/L of uranium, whose concentrations in both hot spring water and geothermal water are 10 -5 g/L. Most of samples are at normal radioactive background level, some higher contents were determined in a few samples

  13. The biodiversity hotspot as evolutionary hot-bed: spectacular radiation of Erica in the Cape Floristic Region.

    Science.gov (United States)

    Pirie, M D; Oliver, E G H; Mugrabi de Kuppler, A; Gehrke, B; Le Maitre, N C; Kandziora, M; Bellstedt, D U

    2016-09-17

    The disproportionate species richness of the world's biodiversity hotspots could be explained by low extinction (the evolutionary "museum") and/or high speciation (the "hot-bed") models. We test these models using the largest of the species rich plant groups that characterise the botanically diverse Cape Floristic Region (CFR): the genus Erica L. We generate a novel phylogenetic hypothesis informed by nuclear and plastid DNA sequences of c. 60 % of the c. 800 Erica species (of which 690 are endemic to the CFR), and use this to estimate clade ages (using RELTIME; BEAST), net diversification rates (GEIGER), and shifts in rates of diversification in different areas (BAMM; MuSSE). The diversity of Erica species in the CFR is the result of a single radiation within the last c. 15 million years. Compared to ancestral lineages in the Palearctic, the rate of speciation accelerated across Africa and Madagascar, with a further burst of speciation within the CFR that also exceeds the net diversification rates of other Cape clades. Erica exemplifies the "hotbed" model of assemblage through recent speciation, implying that with the advent of the modern Cape a multitude of new niches opened and were successively occupied through local species diversification.

  14. Impact and consequences of evapotranspiration changes on water resources availability in the arid Zhangye Basin, China

    NARCIS (Netherlands)

    Jin, X.; Schaepman, M.E.; Clevers, J.G.P.W.; Su, Z.

    2009-01-01

    Evapotranspiration (ET) plays an important role in the hydrological cycle and it is essential to estimate ET accurately for the evaluation of available water resources. This is most important in arid and semi-arid regions. In this paper, the long-term changes in daily ET in the semi-arid Zhangye

  15. Nonequilibrium phenomena and determination of plasma parameters in the hot core of the cathode region in free-burning arc discharges

    International Nuclear Information System (INIS)

    Kuehn, Gerrit; Kock, Manfred

    2007-01-01

    We present spectroscopic measurements of plasma parameters (electron density n e , electron temperature T e , gas temperature T g , underpopulation factor b) in the hot-core region in front of the cathode of a low-current, free-burning arc discharge in argon under atmospheric pressure. The discharge is operated in the hot-core mode, creating a hot cathode region with plasma parameters similar to high-current arcs in spite of the fact that we use comparatively low currents (less than 20 A). We use continuum emission and (optically thin) line emission to determine n e and T e . We apply relaxation measurements based on a power-interruption technique to investigate deviations from local thermodynamic equilibrium (LTE). These measurements let us determine the gas temperature T g . All measurements are performed side-on with charge-coupled-device cameras as detectors, so that all measured plasma parameters are spatially resolved after an Abel inversion. This yields the first ever spatially resolved observation of the non-LTE phenomena of the hot core in the near-cathode region of free-burning arcs. The results only partly coincide with previously published predictions and measurements in the literature

  16. Molecular analysis of the distribution of chromosomal breakpoints: characterization of a 'hot' region for breaks in human chromosome 11

    International Nuclear Information System (INIS)

    Vannais, D.B.; Hirai, Y.; Cologne, J.B.; Waldren, C.A.; Ueno, A.

    2003-01-01

    Full text: Ionizing radiation randomly damages DNA and chromosomes whereas subsequent chromosome breaks are non-random. Assuming, as an ideal and naive but useful proposition, that breaks are equally likely anywhere in the chromosome and that a deletion always occurs between two breaks, the frequency of fragments would decrease linearly with increasing fragment size. This simple distribution is not, however, observed. To shed light on the 'real' situation of break formation we mapped breakpoints in the human chromosome no. 11 of 353 independent CD59- mutants isolated from human/hamster hybrid AL cells exposed to radiations (high and low dose-rate gamma rays, high LET carbon or nitrogen ions, protons) or chemicals (arsenic or irradiated, mutagenic histidine) or unexposed. The number of breaks per unit length of DNA differed significantly in different regions of chromosome 11.The highest level of breaks (140/mbp) were in the 0.8 mbp segment between CD59 and Catalase (CAT). Finer mapping of break points was carried out using 26 PCR primer pairs spread across this interval in 15 independent mutants. In two mutants, the break point was in a 107 bp fragment; in the other 13 the breaks were in a single 35 mbp fragment, but not all were at exactly the same site; 4 of 13 occurred in 3 different 3 mbp sub-segments. We are sequencing these fragments to look for such features as repeats: 'colder' regions like that between CD59 and WT will also be analyzed. But, since at least some breaks occurred at different sites and the frequency and distribution of breaks was about the same for all treatments, our we postulate that hot (and cold spots) may be due more to structural features or specific repair than to sequence or type of damage

  17. Climate change impacts in the Middle East and Northern Africa (MENA) region and their implications for vulnerable population groups

    NARCIS (Netherlands)

    Waha, Katharina; Krummenauer, Linda; Adams, Sophie; Aich, Valentin; Baarsch, Florent; Coumou, Dim; Fader, Marianela; Hoff, Holger; Jobbins, Guy; Marcus, Rachel; Mengel, Matthias; Otto, Ilona M.; Perrette, Mahé; Rocha, Marcia; Robinson, Alexander; Schleussner, Carl Friedrich

    2017-01-01

    The Middle East and North Africa (MENA) region emerges as one of the hot spots for worsening extreme heat, drought and aridity conditions under climate change. A synthesis of peer-reviewed literature from 2010 to date and own modeling work on biophysical impacts of climate change on selected sectors

  18. Experimental and Numerical Study of Bottom Rack Occlusion by Flow with Gravel-Sized Sediment. Application to Ephemeral Streams in Semi-Arid Regions

    Directory of Open Access Journals (Sweden)

    Luis G. Castillo

    2016-04-01

    Full Text Available Rainfall runoff collection in ephemeral streams is an objective in semi-arid zones. Rack intake systems are proposed to collect these flash floods with intensive sediment transport. The design parameters address the problem of clogging the spacing between bars. Experiments for two different void ratio racks are shown. Flows, longitudinal slopes in the rack, and water with three gravel-sized sediments were tested. Results such as effective void ratio due to the gravel deposition over the rack, the evolution of the flow rejected during each test, and the quantification of materials collected and deposited, are presented. The optimal longitudinal rack slope seems to be close to 30%. The effective void ratio is related to several hydraulic parameters calculated at the beginning of the rack. Some adjustments were proposed to predict the effective void ratio.

  19. Hot Flashes

    Science.gov (United States)

    Hot flashes Overview Hot flashes are sudden feelings of warmth, which are usually most intense over the face, neck and chest. Your skin might redden, as if you're blushing. Hot flashes can also cause sweating, and if you ...

  20. HOT 2015

    DEFF Research Database (Denmark)

    Hannibal, Sara Stefansen

    2016-01-01

    HOT samler og formidler 21 literacykyndiges bud på, hvad der er hot, og hvad der bør være hot inden for literacy – og deres begrundelser for disse bud.......HOT samler og formidler 21 literacykyndiges bud på, hvad der er hot, og hvad der bør være hot inden for literacy – og deres begrundelser for disse bud....

  1. Future aridity under conditions of global climate change

    Science.gov (United States)

    Asadi Zarch, Mohammad Amin; Sivakumar, Bellie; Malekinezhad, Hossein; Sharma, Ashish

    2017-11-01

    Global climate change is anticipated to cause some major changes in hydroclimatic conditions around the world. As aridity is a reliable indicator of potential available water, assessment of its changes under future climatic conditions is important for proper management of water. This study employs the UNESCO aridity/humidity index, which is a derivative of precipitation (P) and potential evapotranspiration (PET), for assessment of aridity. Historical (1901-2005) simulations and future (2006-2100) projections of 22 global climate models (GCMs) from the fifth phase of the Coupled Model Intercomparison Project (CMIP5) are studied. The Nested Bias Correction (NBC) approach is used to correct possible biases of precipitation (simulated directly by the GCMs) and PET (estimated by applying FAO56-Penman-Monteith model on simulated parameters of the GCMs). To detect future aridity changes, the areal extents of the aridity zones in the past and future periods as well as through four sub-periods (2006-2025, 2026-2050, 2051-2075, and 2076-2100) of the future are compared. The results indicate that changes in climate will alter the areal extents of aridity zones in the future. In general, from the first sub-period towards the last one, the area covered by hyper-arid, arid, semi-arid, and sub-humid zones will increase (by 7.46%, 7.01%, 5.80%, and 2.78%, respectively), while the area of the humid regions will decrease (by 4.76%), suggesting that there will be less water over the global land area in the future. To understand the cause of these changes, precipitation and PET are also separately assumed to be stationary throughout the four future sub-periods and the resulting aridity changes are then analyzed. The results reveal that the aridity changes are mostly caused by the positive PET trends, even though the slight precipitation increase lessens the magnitude of the changes.

  2. Responses of Surface Runoff to Climate Change and Human Activities in the Arid Region of Central Asia: A Case Study in the Tarim River Basin, China

    Science.gov (United States)

    Xu, Changchun; Chen, Yaning; Chen, Yapeng; Zhao, Ruifeng; Ding, Hui

    2013-04-01

    Based on hydrological and climatic data and land use/cover change data covering the period from 1957 to 2009, this paper investigates the hydrological responses to climate change and to human activities in the arid Tarim River basin (TRB). The results show that the surface runoff of three headstreams (Aksu River, Yarkant River and Hotan River) of the Tarim River exhibited a significant increasing trend since 1960s and entered an even higher-runoff stage in 1994. In the contrary, the surface runoff of Tarim mainstream displayed a persistent decreasing trend since 1960s. The increasing trend of surface runoff in the headstreams can be attributed to the combined effects of both temperature and precipitation changes during the past five decades. But, the decreasing trend of surface runoff in the mainstream and the observed alterations of the temporal and spatial distribution patterns were mainly due to the adverse impacts of human activities. Specifically, increasingly intensified water consumption for irrigation and the associated massive constructions of water conservancy projects were responsible for the decreasing trend of runoff in the mainstream. And, the decreasing trend has been severely jeopardizing the ecological security in the lower reaches. It is now unequivocally clear that water-use conflicts among different sectors and water-use competitions between upper and lower reaches are approaching to dangerous levels in TRB that is thus crying for implementing an integrated river basin management scheme.

  3. Growth and Nutrient Status of Introduced Black Locust (Robinia pseudoacacia L.) Afforestation in Arid and Semi Arid Areas of Iran

    OpenAIRE

    Moshki, A.; Lamersdorf, N. P.

    2011-01-01

    Under global climate change it is expected that many arid regions in the world will experience enhanced desertification in the next decades. Black locust (Robinia pseudoacacia L.) is a one commonly used species for afforestation projects in arid regions of Iran due to its soil rehabilitation capabilities. This study aims to characterize how Robinia growth parameters and nutrient status interacted and were influenced soil properties. The experiment was conducted at three Robinia plantations in...

  4. Partitioning of evapotranspiration using a stable isotope technique in an arid and high temperature agricultural production system

    KAUST Repository

    Lu, Xuefei; Liang, Liyin L.; Wang, Lixin; Jenerette, G. Darrel; McCabe, Matthew; Grantz, David A.

    2016-01-01

    Agricultural production in the hot and arid low desert systems of southern California relies heavily on irrigation. A better understanding of how much and to what extent irrigated water is transpired by crops relative to being lost through

  5. Aridity under conditions of increased CO2

    Science.gov (United States)

    Greve, Peter; Roderick, Micheal L.; Seneviratne, Sonia I.

    2016-04-01

    A string of recent of studies led to the wide-held assumption that aridity will increase under conditions of increasing atmospheric CO2 concentrations and associated global warming. Such results generally build upon analyses of changes in the 'aridity index' (the ratio of potential evaporation to precipitation) and can be described as a direct thermodynamic effect on atmospheric water demand due to increasing temperatures. However, there is widespread evidence that contradicts the 'warmer is more arid' interpretation, leading to the 'global aridity paradox' (Roderick et al. 2015, WRR). Here we provide a comprehensive assessment of modeled changes in a broad set of dryness metrics (primarily based on a range of measures of water availability) over a large range of realistic atmospheric CO2 concentrations. We use an ensemble of simulations from of state-of-the-art climate models to analyse both equilibrium climate experiments and transient historical simulations and future projections. Our results show that dryness is, under conditions of increasing atmospheric CO2 concentrations and related global warming, generally decreasing at global scales. At regional scales we do, however, identify areas that undergo changes towards drier conditions, located primarily in subtropical climate regions and the Amazon Basin. Nonetheless, the majority of regions, especially in tropical and mid- to northern high latitudes areas, display wetting conditions in a warming world. Our results contradict previous findings and highlight the need to comprehensively assess all aspects of changes in hydroclimatological conditions at the land surface. Roderick, M. L., P. Greve, and G. D. Farquhar (2015), On the assessment of aridity with changes in atmospheric CO2, Water Resour. Res., 51, 5450-5463

  6. Assessment of vulnerability in karst aquifers using a quantitative integrated numerical model: catchment characterization and high resolution monitoring - Application to semi-arid regions- Lebanon.

    Science.gov (United States)

    Doummar, Joanna; Aoun, Michel; Andari, Fouad

    2016-04-01

    Karst aquifers are highly heterogeneous and characterized by a duality of recharge (concentrated; fast versus diffuse; slow) and a duality of flow which directly influences groundwater flow and spring responses. Given this heterogeneity in flow and infiltration, karst aquifers do not always obey standard hydraulic laws. Therefore the assessment of their vulnerability reveals to be challenging. Studies have shown that vulnerability of aquifers is highly governed by recharge to groundwater. On the other hand specific parameters appear to play a major role in the spatial and temporal distribution of infiltration on a karst system, thus greatly influencing the discharge rates observed at a karst spring, and consequently the vulnerability of a spring. This heterogeneity can only be depicted using an integrated numerical model to quantify recharge spatially and assess the spatial and temporal vulnerability of a catchment for contamination. In the framework of a three-year PEER NSF/USAID funded project, the vulnerability of a karst catchment in Lebanon is assessed quantitatively using a numerical approach. The aim of the project is also to refine actual evapotranspiration rates and spatial recharge distribution in a semi arid environment. For this purpose, a monitoring network was installed since July 2014 on two different pilot karst catchment (drained by Qachqouch Spring and Assal Spring) to collect high resolution data to be used in an integrated catchment numerical model with MIKE SHE, DHI including climate, unsaturated zone, and saturated zone. Catchment characterization essential for the model included geological mapping and karst features (e.g., dolines) survey as they contribute to fast flow. Tracer experiments were performed under different flow conditions (snow melt and low flow) to delineate the catchment area, reveal groundwater velocities and response to snowmelt events. An assessment of spring response after precipitation events allowed the estimation of the

  7. Carbon and water dynamics of a bioenergy crop (Cynara cardunculus L. under different meteorological conditions in a semi-arid region

    Directory of Open Access Journals (Sweden)

    Gianfranco Rana

    2017-12-01

    Full Text Available To evaluate the environmental adaptability of cultivated cardoon (Cynara cardunculus L. its water use efficiency [(WUE – ratio between net ecosystem exchange (NEE and evapotranspiration (ET] was analysed. The crop was cultivated in South Italy and WUE was evaluated at different time scales during two seasons: wet and dry. Even if the crop development is similar in the two seasons, plants delay their development in the presence of drought, showing, in this way, an improvement in their adaptability. Seasonal WUE in the dry season is greater than in the wet one by +11.2%, and this is also confirmed at monthly and daily scale. Hourly analysis around the full development phase shows that WUE is greater during the wet season than during the dry one, this being explainable when considering the impact of the drivers [(photosynthetically active radiation (PAR, vapour pressure deficit (VPD, and air temperature (Tair] on CO2 and H2O exchanges by stomatal regulation. The saturation values of NEE in function of PAR (threshold 2.5 MJ m–2h–1 and VPD (threshold 10 hPa are greater during the wet season than the dry one. Furthermore, also the linear relationships between ET and PAR and VPD showed higher slopes in the wet season than in the dry one. Drought causes reduction in both photosynthesis and evapotranspiration by stomatal regulation, however, the photosynthesis process is surely more sensitive to water stress than the crop transpiration, thus demonstrating the good adaptability of this crop to scarce water availability of semi-arid conditions.

  8. Effects of Tillage Methods on Some Soil Physical Properties, Growth and Yield of Water Melon in a Semi-Arid Region of Nigeria

    Directory of Open Access Journals (Sweden)

    A. Dauda

    2017-02-01

    Full Text Available An appropriate tillage method is necessary to create an optimum seed bed condition for optimum crop growth and yield. Two-year field experiment was conducted in 2013 and 2014 to investigate the effects of different tillage methods on the physical properties of sandy loam soil, growth and yield of water melon (Citrullus vulgaris in a semi-arid environment. The Tillage treatments were disc ploughing plus disc harrowing (DP+DH, double disc ploughing (DDP, double disc harrowing (DDH, disc ploughing (DP and disc harrowing (DH as minimum tillage (MT and zero tillage (ZT and direct drilling method (control. The watermelon seeds were Planted manually placing three (3 seeds per hole at an interval of 1.5m along the rows and 50cm between the rows at an average depth of 5cm. The treatments were laid in a randomized complete block design (RCBD with four replications. Results showed that disc ploughing + disc harrowing (DP+DH was found to be more appropriate and profitable tillage method in improving soil physical properties and growth and yield of water melon in a sandy loam soil. Watermelon yield, fruit weight (FW, fruit length (FL, fruit diameter (FD and leaf area index (LAI were significantly influenced (P=0.05, but influence of tillage treatments were not significant on the number of fruit per plant (NFPP. A numerical value of 31.0t/ha, 26.0, 5.4kg, 29.0cm, and 33.8cm were recorded for maximum crop yield, NFPP, FW, FD and FL respectively in DP+DH-treated plots. For zero tillage (ZT treatment, maximum of crop yield and NFPP were 26.5t/ha and 20.0 respectively. Thus for enhanced growth and yield of watermelon, DP/DH would be more preferable. The orthodox method of zero tillage is out rightly discouraged

  9. Probability-based classifications for spatially characterizing the water temperatures and discharge rates of hot springs in the Tatun Volcanic Region, Taiwan.

    Science.gov (United States)

    Jang, Cheng-Shin

    2015-05-01

    Accurately classifying the spatial features of the water temperatures and discharge rates of hot springs is crucial for environmental resources use and management. This study spatially characterized classifications of the water temperatures and discharge rates of hot springs in the Tatun Volcanic Region of Northern Taiwan by using indicator kriging (IK). The water temperatures and discharge rates of the springs were first assigned to high, moderate, and low categories according to the two thresholds of the proposed spring classification criteria. IK was then used to model the occurrence probabilities of the water temperatures and discharge rates of the springs and probabilistically determine their categories. Finally, nine combinations were acquired from the probability-based classifications for the spatial features of the water temperatures and discharge rates of the springs. Moreover, various combinations of spring water features were examined according to seven subzones of spring use in the study region. The research results reveal that probability-based classifications using IK provide practicable insights related to propagating the uncertainty of classifications according to the spatial features of the water temperatures and discharge rates of the springs. The springs in the Beitou (BT), Xingyi Road (XYR), Zhongshanlou (ZSL), and Lengshuikeng (LSK) subzones are suitable for supplying tourism hotels with a sufficient quantity of spring water because they have high or moderate discharge rates. Furthermore, natural hot springs in riverbeds and valleys should be developed in the Dingbeitou (DBT), ZSL, Xiayoukeng (XYK), and Macao (MC) subzones because of low discharge rates and low or moderate water temperatures.

  10. Soil Thermal Balance Analysis for a Ground Source Heat Pump System in a Hot-Summer and Cold-Winter Region

    Directory of Open Access Journals (Sweden)

    Zhongchao Zhao

    2018-05-01

    Full Text Available As a renewable and high energy efficiency technology providing air conditioning and domestic hot water, the ground source heat pump system (GSHPS has been extensively used worldwide in recent years. Compared with conventional systems, GSHPSs with heat recovery reject less heat into the soil and extract more heat from it, which can help reduce soil thermal imbalance in hot-summer and cold-winter regions. In this paper, conventional GSHPS, and GSHPS with different heat recovery ratios, in a typical city were compared based on thermal imbalance ratios, average soil temperatures and soil temperature increases. The transient system simulation software was used to simulate the operation performance of GSHPS. The thermal imbalance ratio and soil temperature decreased with increasing heat recovery ratio. After 20 years of operation, the soil thermal imbalance ratios of the GSHPS were 29.2%, 21.1%, 16%, and 5.2%, and the soil temperature rises were 8.78 °C, 5.25 °C, 3.44 °C, and 0.34 °C, while the heat recovery ratios were 0, 18%, 30% and 53%, respectively. Consequently, a GSHPS with heat recovery is a potentially efficient and economical approach for buildings in hot-summer and cold-winter regions.

  11. The potential of a modified physiologically equivalent temperature (mPET) based on local thermal comfort perception in hot and humid regions

    Science.gov (United States)

    Lin, Tzu-Ping; Yang, Shing-Ru; Chen, Yung-Chang; Matzarakis, Andreas

    2018-02-01

    Physiologically equivalent temperature (PET) is a thermal index that is widely used in the field of human biometeorology and urban bioclimate. However, it has several limitations, including its poor ability to predict thermo-physiological parameters and its weak response to both clothing insulation and humid conditions. A modified PET (mPET) was therefore developed to address these shortcomings. To determine whether the application of mPET in hot-humid regions is more appropriate than the PET, an analysis of a thermal comfort survey database, containing 2071 questionnaires collected from participants in hot-humid Taiwan, was conducted. The results indicate that the thermal comfort range is similar (26-30 °C) when the mPET and PET are applied as thermal indices to the database. The sensitivity test for vapor pressure and clothing insulation also show that the mPET responds well to the behavior and perceptions of local people in a subtropical climate.