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Sample records for repeated droughts showed

  1. Photosynthesis of Digitaria ciliaris during repeated soil drought and rewatering

    Institute of Scientific and Technical Information of China (English)

    YaYong Luo; XueYong Zhao; JingHui Zhang; YuLin Li; XiaoAn Zuo; DianChao Sun

    2015-01-01

    The ability of psammophyte photosynthesis to withstand and recover from severe droughts is crucial for vegetation sta-bility in semi-arid sandy lands. The responses of gas exchange and chlorophyll fluorescence of an annual grass, Digitaria ciliaris, were measured through three soil drought and rewatering cycles. Results showed that the net photosynthesis rate (Pn) decreased by 92%, 95%, and 63%at end of the three drought periods, respectively, water use efficiency (WUE) de-creased by 67%, 54%, and 48%, while the constant intercellular CO2 concentration (Ci) increased by 1.08, 0.88, and 0.45 times. During those three cycles, the trapping probability with no dark adaptation (Fv′/Fm′) decreased by 55%, 51%, and 9%, the electron transport per cross section (ET0′/CS0′) decreased by 63%, 42%, and 18%, and the dissipation per cross section (DI0′/CS0′) increased by 97%, 96%, and 21%. These results indicated that D. ciliaris was subjected to photoinhi-bition and some non-stomatal limitation of photosynthesis under drought. However, after four days of rewatering, its photosynthetic characteristics were restored to control values. This capability to recover from drought may contribute to making the plant's use of water as efficient as possible. Furthermore, the photosynthesis decreased more slowly in the subsequent drought cycles than in the first cycle, allowing D. ciliaris to enhance its future drought tolerance after drought hardening. Thus, it acclimatizes itself to repeated soil drought.

  2. Amazon forest response to repeated droughts

    Science.gov (United States)

    Feldpausch, T. R.; Phillips, O. L.; Brienen, R. J. W.; Gloor, E.; Lloyd, J.; Lopez-Gonzalez, G.; Monteagudo-Mendoza, A.; Malhi, Y.; Alarcón, A.; Álvarez Dávila, E.; Alvarez-Loayza, P.; Andrade, A.; Aragao, L. E. O. C.; Arroyo, L.; Aymard C., G. A.; Baker, T. R.; Baraloto, C.; Barroso, J.; Bonal, D.; Castro, W.; Chama, V.; Chave, J.; Domingues, T. F.; Fauset, S.; Groot, N.; Honorio Coronado, E.; Laurance, S.; Laurance, W. F.; Lewis, S. L.; Licona, J. C.; Marimon, B. S.; Marimon-Junior, B. H.; Mendoza Bautista, C.; Neill, D. A.; Oliveira, E. A.; Oliveira dos Santos, C.; Pallqui Camacho, N. C.; Pardo-Molina, G.; Prieto, A.; Quesada, C. A.; Ramírez, F.; Ramírez-Angulo, H.; Réjou-Méchain, M.; Rudas, A.; Saiz, G.; Salomão, R. P.; Silva-Espejo, J. E.; Silveira, M.; Steege, H.; Stropp, J.; Terborgh, J.; Thomas-Caesar, R.; Heijden, G. M. F.; Vásquez Martinez, R.; Vilanova, E.; Vos, V. A.

    2016-07-01

    The Amazon Basin has experienced more variable climate over the last decade, with a severe and widespread drought in 2005 causing large basin-wide losses of biomass. A drought of similar climatological magnitude occurred again in 2010; however, there has been no basin-wide ground-based evaluation of effects on vegetation. We examine to what extent the 2010 drought affected forest dynamics using ground-based observations of mortality and growth from an extensive forest plot network. We find that during the 2010 drought interval, forests did not gain biomass (net change: -0.43 Mg ha-1, confidence interval (CI): -1.11, 0.19, n = 97), regardless of whether forests experienced precipitation deficit anomalies. This contrasted with a long-term biomass sink during the baseline pre-2010 drought period (1998 to pre-2010) of 1.33 Mg ha-1 yr-1 (CI: 0.90, 1.74, p drought (i.e., reversal of the baseline net sink) was -1.95 Mg ha-1 yr-1 (CI:-2.77, -1.18; p drought history. Thus, there was no evidence that pre-2010 droughts compounded the effects of the 2010 drought. We detected a systematic basin-wide impact of the 2010 drought on tree growth rates across Amazonia, which was related to the strength of the moisture deficit. This impact differed from the drought event in 2005 which did not affect productivity. Based on these ground data, live biomass in trees and corresponding estimates of live biomass in lianas and roots, we estimate that intact forests in Amazonia were carbon neutral in 2010 (-0.07 Pg C yr-1 CI:-0.42, 0.23), consistent with results from an independent analysis of airborne estimates of land-atmospheric fluxes during 2010. Relative to the long-term mean, the 2010 drought resulted in a reduction in biomass carbon uptake of 1.1 Pg C, compared to 1.6 Pg C for the 2005 event.

  3. Repeated drought alters resistance of seed bank regeneration in baldcypress swamps of North America

    Science.gov (United States)

    Lei, Ting; Middleton, Beth A.

    2017-01-01

    Recurring drying and wetting events are likely to increase in frequency and intensity in predicted future droughts in the central USA and alter the regeneration potential of species. We explored the resistance of seed banks to successive droughts in 53 sites across the nine locations in baldcypress swamps in the southeastern USA. Along the Mississippi River Alluvial Valley and northern Gulf of Mexico, we investigated the capacity of seed banks to retain viable seeds after successive periods of drying and wetting in a greenhouse study. Mean differences in species richness and seed density were compared to examine the interactions of successive droughts, geographical location and water regime. The results showed that both species richness and total density of germinating seedlings decreased over repeated drought trials. These responses were more pronounced in geographical areas with higher annual mean temperature. In seed banks across the southeastern swamp region, most species were exhausted after Trial 2 or 3, except for semiaquatic species in Illinois and Tennessee, and aquatic species in Texas. Distinct geographical trends in seed bank resistance to drought demonstrate that climate-induced drying of baldcypress swamps could influence the regeneration of species differently across their ranges. Despite the health of adult individuals, lack of regeneration may push ecosystems into a relict status. Seed bank depletion by germination without replenishment may be a major conservation threat in a future with recurring droughts far less severe than megadrought. Nevertheless, the protection of moist refugia might aid conservation.

  4. Genetic variation, phenotypic stability, and repeatability of drought response in European larch throughout 50 years in a common garden experiment.

    Science.gov (United States)

    George, Jan-Peter; Grabner, Michael; Karanitsch-Ackerl, Sandra; Mayer, Konrad; Weißenbacher, Lambert; Schueler, Silvio; Mäkelä, Annikki

    2017-01-31

    Assessing intra-specific variation in drought stress response is required to mitigate the consequences of climate change on forest ecosystems. Previous studies suggest that European larch (Larix decidua Mill.), an important European conifer in mountainous and alpine forests, is highly vulnerable to drought. In light of this, we estimated the genetic variation in drought sensitivity and its degree of genetic determination in a 50-year-old common garden experiment in the drought-prone northeastern Austria. Tree ring data from larch provenances originating from across the species' natural range were used to estimate the drought reaction in four consecutive drought events (1977, 1981, 1990–1994, and 2003) with extremely low standardized precipitation- and evapotranspiration-index values that affected growth in all provenances. We found significant differences among provenances across the four drought periods for the trees’ capacity to withstand drought (resistance) and for their capacity to reach pre-drought growth levels after drought (resilience). Provenances from the species' northern distribution limit in the Polish lowlands were found to be more drought resistant and showed higher stability across all drought periods than provenances from mountainous habitats at the southern fringe. The degree of genetic determination, as estimated by the repeatability, ranged up to 0.39, but significantly differed among provenances, indicating varying degrees of natural selection at the provenance origin. Generally, the relationship between the provenances’ source climate and drought behavior was weak, suggesting that the contrasting patterns of drought response are a result of both genetic divergence out of different refugial lineages and local adaptation to summer or winter drought conditions. Our analysis suggests that European larch posseses high genetic variation among and within provenances that can be used for assisted migration and breeding programs.

  5. Contrasting effects of repeated summer drought on soil carbon efflux in hydric and mesic heathland soils

    DEFF Research Database (Denmark)

    Sowerby, Alwyn; Emmett, Bridget A.; Tietema, Albert

    2008-01-01

    Current predictions of climate change include altered rainfall patterns throughout Europe, continental USA and areas such as the Amazon. The effect of this on soil carbon efflux remains unclear although several modelling studies have highlighted the potential importance of drought for carbon...... storage. To test the importance of drought, and more importantly repeated drought year-on-year, we used automated retractable curtains to exclude rain and produce repeated summer drought in three heathlands at varying moisture conditions. This included a hydric system limited by water-excess (in the UK......) and two mesic systems with seasonal water limitation in Denmark (DK) and the Netherlands (NL). The experimental rainfall reductions were set to reflect single year droughts observed in the last decade with exclusion of rain for 2-3 months of the year resulting in a 20-26% reduction in annual rainfall...

  6. ISSR markers based on GA and AG repeats reveal genetic relationship among rice varieties tolerant to drought,flood,or salinity

    Institute of Scientific and Technical Information of China (English)

    Ch Surendhar REDDY; A.Prasad BABU; B.P.Mallikarjuna SWAMY; K.KALADHAR; N.SARLA

    2009-01-01

    Drought,flood,salinity,or a combination of these limits rice production.Several rice varieties are well known for their tolerance to specific abiotic stresses.We determined genetic relationship among 12 rice varieties including 9 tolerant to drought,flood,or salinity using inter-simple sequence repeat (ISSR) markers.Based on all markers,the nine tolerant varieties formed one cluster distinct from the cluster of three control varieties.The salt-tolerant varieties were closest to two flood-tolerant varieties,and together they were distinct from the drought-tolerant varieties.(GA)8 YG was the most informative primer,showing the highest polymorphic information content (PIC) and resolving power (Rp).The drought-,flood-,and salt-tolerant varieties grouped in three distinct clusters within the group of tolerant varieties,when (GA)8 YG was used.Sabita was the only exception.The two aus varieties,Nagina22 and FR13A,were separated and grouped with the drought-and flood-tolerant varieties,respectively,but they were together in dendrograms based on other primers.The results show that ISSR markers associated with (GA)8 YG delineated the three groups of stress-tolerant varieties from each other and can be used to identify genes/new alleles associated with the three abiotic stresses in rice germplasm.

  7. Soil microarthropods are only weakly impacted after 13 years of repeated drought treatment in wet and dry heathland soils

    DEFF Research Database (Denmark)

    Holmstrup, Martin; Sørensen, Jesper G.; Schmidt, Inger Kappel

    2013-01-01

    Studies of biological responses in the terrestrial environment to rapid changes in climate have mostly been concerned with aboveground biota, whereas less is known of belowground organisms. The present study focuses on mites and springtails of heathland ecosystems and how the microarthropod...... and frequency of drought had only weak persistent effects on springtail species composition, but practically no effect on major mite groups (Oribatida, Prostigmata or Mesostigmata) suggesting that ecosystem functions of microarthropods may only be transiently impacted by repeated spring or summer drought....

  8. Estimating carbon and showing impacts of drought using satellite data in regression-tree models

    Science.gov (United States)

    Boyte, Stephen; Wylie, Bruce K.; Howard, Danny; Dahal, Devendra; Gilmanov, Tagir G.

    2018-01-01

    Integrating spatially explicit biogeophysical and remotely sensed data into regression-tree models enables the spatial extrapolation of training data over large geographic spaces, allowing a better understanding of broad-scale ecosystem processes. The current study presents annual gross primary production (GPP) and annual ecosystem respiration (RE) for 2000–2013 in several short-statured vegetation types using carbon flux data from towers that are located strategically across the conterminous United States (CONUS). We calculate carbon fluxes (annual net ecosystem production [NEP]) for each year in our study period, which includes 2012 when drought and higher-than-normal temperatures influence vegetation productivity in large parts of the study area. We present and analyse carbon flux dynamics in the CONUS to better understand how drought affects GPP, RE, and NEP. Model accuracy metrics show strong correlation coefficients (r) (r ≥ 94%) between training and estimated data for both GPP and RE. Overall, average annual GPP, RE, and NEP are relatively constant throughout the study period except during 2012 when almost 60% less carbon is sequestered than normal. These results allow us to conclude that this modelling method effectively estimates carbon dynamics through time and allows the exploration of impacts of meteorological anomalies and vegetation types on carbon dynamics.

  9. Repeat length variation in the 5'UTR of myo-inositol monophosphatase gene is related to phytic acid content and contributes to drought tolerance in chickpea (Cicer arietinum L.).

    Science.gov (United States)

    Joshi-Saha, Archana; Reddy, Kandali S

    2015-09-01

    Myo-inositol metabolism plays a significant role in plant growth and development, and is also used as a precursor for many important metabolites, such as ascorbate, pinitol, and phytate. Phytate (inositol hexakisphosphate) is the major storage pool for phosphate in the seeds. It is utilized during seed germination and growth of the developing embryo. In addition, it is implicated in protection against oxidative stress. In the present study, a panel of chickpea accessions was used for an association analysis. Association analysis accounting for population structure and relative kinship identified alleles of a simple sequence repeat marker, NCPGR90, that are associated with both phytic acid content and drought tolerance. These alleles varied with respect to the dinucleotide CT repeats present within the marker. NCPGR90 located to the 5'UTR of chickpea myo-inositol monophosphatase gene (CaIMP) and showed transcript length variation in drought-tolerant and drought-susceptible accessions. CaIMP from a drought-tolerant accession with a smaller repeat was almost 2-fold upregulated as compared to a susceptible accession having a longer repeat, even under control non-stressed conditions. This study suggests an evolution of simple sequence repeat length variation in CaIMP, which might be regulating phytic acid levels to confer drought tolerance in natural populations of chickpea.

  10. Drought

    NARCIS (Netherlands)

    Quevauviller, P.; Lanen, Van Henny A.J.

    2014-01-01

    Drought is one of the most extreme weather-related natural hazards. It differs from other hydrometeorological extremes in several ways. It develops gradually and usually over large areas (transnational), mostly resulting from a prolonged period (from months to years) of below-normal precipitation

  11. Induced pluripotent stem cells from patients with Huntington's disease show CAG-repeat-expansion-associated phenotypes.

    Science.gov (United States)

    2012-08-03

    Huntington's disease (HD) is an inherited neurodegenerative disorder caused by an expanded stretch of CAG trinucleotide repeats that results in neuronal dysfunction and death. Here, The HD Consortium reports the generation and characterization of 14 induced pluripotent stem cell (iPSC) lines from HD patients and controls. Microarray profiling revealed CAG-repeat-expansion-associated gene expression patterns that distinguish patient lines from controls, and early onset versus late onset HD. Differentiated HD neural cells showed disease-associated changes in electrophysiology, metabolism, cell adhesion, and ultimately cell death for lines with both medium and longer CAG repeat expansions. The longer repeat lines were however the most vulnerable to cellular stressors and BDNF withdrawal, as assessed using a range of assays across consortium laboratories. The HD iPSC collection represents a unique and well-characterized resource to elucidate disease mechanisms in HD and provides a human stem cell platform for screening new candidate therapeutics.

  12. The Mediterranean evergreen Quercus ilex and the semi-deciduous Cistus albidus differ in their leaf gas exchange regulation and acclimation to repeated drought and re-watering cycles.

    Science.gov (United States)

    Galle, Alexander; Florez-Sarasa, Igor; Aououad, Hanan El; Flexas, Jaume

    2011-10-01

    Plants may exhibit some degree of acclimation after experiencing drought, but physiological adjustments to consecutive cycles of drought and re-watering (recovery) have scarcely been studied. The Mediterranean evergreen holm oak (Q. ilex) and the semi-deciduous rockrose (C. albidus) showed some degree of acclimation after the first of three drought cycles (S1, S2, and S3). For instance, during S2 and S3 both species retained higher relative leaf water contents than during S1, despite reaching similar leaf water potentials. However, both species showed remarkable differences in their photosynthetic acclimation to repeated drought cycles. Both species decreased photosynthesis to a similar extent during the three cycles (20-40% of control values). However, after S1 and S2, photosynthesis recovered only to 80% of control values in holm oak, due to persistently low stomatal (g(s)) and mesophyll (g(m)) conductances to CO(2). Moreover, leaf intrinsic water use efficiency (WUE) was kept almost constant in this species during the entire experiment. By contrast, photosynthesis of rockrose recovered almost completely after each drought cycle (90-100% of control values), while the WUE was largely and permanently increased (by 50-150%, depending on the day) after S1. This was due to a regulation which consisted in keeping g(s) low (recovering to 50-60% of control values after re-watering) while maintaining a high g(m) (even exceeding control values during re-watering). While the mechanisms to achieve such particular regulation of water and CO(2) diffusion in leaves are unknown, it clearly represents a unique acclimation feature of this species after a drought cycle, which allows it a much better performance during successive drought events. Thus, differences in the photosynthetic acclimation to repeated drought cycles can have important consequences on the relative fitness of different Mediterranean species or growth forms within the frame of climate change scenarios.

  13. Contrasting effects of repeated summer drought on soil carbon efflux in hydric and mesic heathland soils

    NARCIS (Netherlands)

    Sowerby, A.; Emmett, B.A.; Tietema, A.; Beier, C.

    2008-01-01

    Current predictions of climate change include altered rainfall patterns throughout Europe, continental USA and areas such as the Amazon. The effect of this on soil carbon efflux remains unclear although several modelling studies have highlighted the potential importance of drought for carbon

  14. Contrasting effects of repeated summer drought on soil carbon efflux in hydric and mesic heathland soils

    NARCIS (Netherlands)

    Sowerby, A.; Emmett, B.A.; Tietema, A.; Beier, C.

    2008-01-01

    Current predictions of climate change include altered rainfall patterns throughout Europe, continental USA and areas such as the Amazon. The effect of this on soil carbon efflux remains unclear although several modelling studies have highlighted the potential importance of drought for carbon storage

  15. Size Matters a Lot: Drought-Affected Italian Oaks Are Smaller and Show Lower Growth Prior to Tree Death

    Science.gov (United States)

    Colangelo, Michele; Camarero, Jesús J.; Borghetti, Marco; Gazol, Antonio; Gentilesca, Tiziana; Ripullone, Francesco

    2017-01-01

    Hydraulic theory suggests that tall trees are at greater risk of drought-triggered death caused by hydraulic failure than small trees. In addition the drop in growth, observed in several tree species prior to death, is often interpreted as an early-warning signal of impending death. We test these hypotheses by comparing size, growth, and wood-anatomy patterns of living and now-dead trees in two Italian oak forests showing recent mortality episodes. The mortality probability of trees is modeled as a function of recent growth and tree size. Drift-diffusion-jump (DDJ) metrics are used to detect early-warning signals. We found that the tallest trees of the anisohydric Italian oak better survived drought contrary to what was predicted by the theory. Dead trees were characterized by a lower height and radial-growth trend than living trees in both study sites. The growth reduction of now-dead trees started about 10 years prior to their death and after two severe spring droughts during the early 2000s. This critical transition in growth was detected by DDJ metrics in the most affected site. Dead trees were also more sensitive to drought stress in this site indicating different susceptibility to water shortage between trees. Dead trees did not form earlywood vessels with smaller lumen diameter than surviving trees but tended to form wider latewood vessels with a higher percentage of vessel area. Since living and dead trees showed similar competition we did not expect that moderate thinning and a reduction in tree density would increase the short-term survival probability of trees. PMID:28270816

  16. BrUGE1 transgenic rice showed improved growth performance with enhanced drought tolerance.

    Science.gov (United States)

    Abdula, Sailila E; Lee, Hye Jung; Kim, Joonki; Niño, Marjohn C; Jung, Yu-Jin; Cho, Young-Chan; Nou, Illsup; Kang, Kwon-Kyoo; Cho, Yong-Gu

    2016-03-01

    UDP-glucose 4-epimerase (UGE) catalyzes the reversible conversion of UDP-glucose to UDP-galactose. To understand the biological function of UGE from Brassica rapa, the gene BrUGE1 was cloned and introduced into the genome of wild type rice 'Gopum' using the Agrobacterium-mediated transformation method. Four lines which carried a single copy gene were selected and forwarded to T3 generation. Agronomic traits evaluation of the transgenic T3 lines (CB01, CB03, and CB06) under optimal field conditions revealed enriched biomass production particularly in panicle length, number of productive tillers, number of spikelets per panicle, and filled spikelets. These remarkably improved agronomic traits were ascribed to a higher photosynthetic rate complemented with higher CO2 assimilation. Transcripts of BrUGE1 in transgenic lines continuously accumulated at higher levels after the 20% PEG6000 treatment, implying its probable role in drought stress regulation. This was paralleled by rapid accumulation of soluble sugars which act as osmoprotectants, leading to delayed leaf rolling and drying. Our findings suggest the potential of BrUGE1 in improving rice growth performance under optimal and water deficit conditions.

  17. Repeat length variation in the dopamine D4 receptor gene shows no evidence of association with schizophrenia

    Energy Technology Data Exchange (ETDEWEB)

    Daniels, J.; Williams, J.; Asherson, P. [Univ. of Wales College of Medicine, Cardiff (United Kingdom)] [and others

    1994-09-15

    The D4 receptor has been shown to exist in several allelic forms reflecting variation in the number of 48 base-pair sequence repeats in the putative cytoplasmic loop. We report a comparison of repeat length variation between schizophrenic patients and controls. Our sample of 106 unrelated schizophrenic cases and 119 controls showed no significant differences in allele or genotype distribution between patients and controls. In particular, we were unable to support the previous observation of an excess of 4-repeat homozygotes in patients. 16 refs., 2 tabs.

  18. Indonesian fire activity and smoke pollution in 2015 show persistent nonlinear sensitivity to El Niño-induced drought

    Science.gov (United States)

    Field, Robert D.; van der Werf, Guido R.; Fanin, Thierry; Fetzer, Eric J.; Fuller, Ryan; Jethva, Hiren; Levy, Robert; Livesey, Nathaniel J.; Luo, Ming; Torres, Omar; Worden, Helen M.

    2016-08-01

    The 2015 fire season and related smoke pollution in Indonesia was more severe than the major 2006 episode, making it the most severe season observed by the NASA Earth Observing System satellites that go back to the early 2000s, namely active fire detections from the Terra and Aqua Moderate Resolution Imaging Spectroradiometers (MODIS), MODIS aerosol optical depth, Terra Measurement of Pollution in the Troposphere (MOPITT) carbon monoxide (CO), Aqua Atmospheric Infrared Sounder (AIRS) CO, Aura Ozone Monitoring Instrument (OMI) aerosol index, and Aura Microwave Limb Sounder (MLS) CO. The MLS CO in the upper troposphere showed a plume of pollution stretching from East Africa to the western Pacific Ocean that persisted for 2 mo. Longer-term records of airport visibility in Sumatra and Kalimantan show that 2015 ranked after 1997 and alongside 1991 and 1994 as among the worst episodes on record. Analysis of yearly dry season rainfall from the Tropical Rainfall Measurement Mission (TRMM) and rain gauges shows that, due to the continued use of fire to clear and prepare land on degraded peat, the Indonesian fire environment continues to have nonlinear sensitivity to dry conditions during prolonged periods with less than 4 mm/d of precipitation, and this sensitivity appears to have increased over Kalimantan. Without significant reforms in land use and the adoption of early warning triggers tied to precipitation forecasts, these intense fire episodes will reoccur during future droughts, usually associated with El Niño events.

  19. Repeated summer drought and re-watering during the first growing year of oak (Quercus petraea delay autumn senescence and bud burst in the following spring

    Directory of Open Access Journals (Sweden)

    Kristine Vander Mijnsbrugge

    2016-03-01

    Full Text Available Climate change predicts harsher summer droughts for mid-latitudes in Europe. To enhance our understanding of the putative impacts on forest regeneration, we studied the response of oak seedlings (Quercus petraea to water deficit. Potted seedlings originating from three locally sourced provenances were subjected to two successive drought periods during the first growing season each followed by a plentiful re-watering. Here we describe survival and phenological responses after the second drought treatment, applying general linear mixed modelling. From the 441 drought treated seedlings 189 subsisted with higher chances of survival among smaller plants and among single plants per pot compared to doubles. Remarkably, survival was independent of the provenance, although relatively more plants had died off in two provenances compared to the third one with mean plant height being higher in one provenance and standard deviation of plant height being higher in the other. Timing of leaf senescence was clearly delayed after the severe drought treatment followed by re-watering, with two seedlings per pot showing a lesser retardation compared to single plants. This delay can be interpreted as a compensation time in which plants recover before entering the subsequent developmental process of leaf senescence, although it renders seedlings more vulnerable to early autumn frosts because of the delayed hardening of the shoots. Onset of bud flush in the subsequent spring still showed a significant but small delay in the drought treated group, independent of the number of seedlings per pot, and can be considered as an after effect of the delayed senescence. In both phenological models significant differences among the three provenances were detected independent from the treatment. The only provenance that is believed to be local of origin, displayed the earliest leaf senescence and the latest flushing, suggesting an adaptation to the local maritime climate. This

  20. Corticosterone stress response shows long-term repeatability and links to personality in free-living Nazca boobies.

    Science.gov (United States)

    Grace, Jacquelyn K; Anderson, David J

    2014-11-01

    The concept of "coping styles", or consistently different responses to stressors, is of broad interest in behavioral ecology and biomedicine. Two critical predictions of this concept are individual consistency of neurophysiological and behavioral responses (relative to population variability) and a negative relationship between aggression/proactivity and hypothalamic-pituitary-adrenal axis reactivity. Recent studies failed to provide strong support for these predictions, especially outside of strictly controlled conditions, and long-term measures to test the first prediction are rare. Here, we demonstrate individual repeatability across 2-3years of maximum circulating corticosterone concentration [CORT] and area under the [CORT] response curve (AUCI) during a standard capture-restraint test in wild, free-living adult Nazca boobies (Sula granti). We also show that the stress response predicts the personality traits aggression and anxiety in these birds (measured in the wild); however, the strength of these results was weak. Maximum [CORT] and AUCI showed higher repeatability between years than baseline [CORT]. After controlling breeding status, sex, mass, date sampled, and their interactions, baseline [CORT] was most closely related to personality traits, followed by AUCI, and then maximum [CORT]. The direction of these relationships depended on whether the testing context was social or non-social. [CORT] parameters had little to no relationship with cross-context plasticity in personality traits. Our results generally affirm two critical predictions of coping styles, but match the emerging trend that these relationships are weak in the wild, and may depend on testing context.

  1. Do monkey F5 mirror neurons show changes in firing rate during repeated observation of natural actions?

    Science.gov (United States)

    Kilner, J M; Kraskov, A; Lemon, R N

    2014-03-01

    Mirror neurons were first discovered in area F5 of macaque monkeys. In humans, noninvasive studies have demonstrated an increased blood oxygen level-dependent (BOLD) signal in homologous motor areas during action observation. One approach to demonstrating that this indicates the existence of mirror neurons in humans has been to employ functional (f)MRI adaptation to test whether the same population of neurons is active during both observation and execution conditions. Although a number of human studies have reported fMRI adaptation in these areas, a recent study has shown that macaque mirror neurons do not attenuate their firing rate with two repetitions. Here we investigated whether mirror neurons modulate their firing rate when monkeys observed the same repeated natural action multiple times. We recorded from 67 mirror neurons in area F5 of two macaque monkeys while they observed an experimenter perform a reach-to-grasp action on a small food reward using a precision grip. Although no changes were detectable for the first two repetitions, we show that both the firing rate and the latency at which mirror neurons discharged during observation were subtly modulated by the repetition of the observed action over 7-10 trials. Significant adaption was mostly found in the period immediately before the grasp was performed. We also found that the local field potential activity in F5 (beta-frequency range, 16-23 Hz), which is attenuated during action observation, also showed systematic changes with repeated observation. These LFP changes occurred well in advance of the mirror neuron adaptation. We conclude that macaque mirror neurons can show intra-modal adaptation, but whether this is related to fMRI adaptation of the BOLD signal requires further investigation.

  2. The SIDER2 elements, interspersed repeated sequences that populate the Leishmania genomes, constitute subfamilies showing chromosomal proximity relationship

    Directory of Open Access Journals (Sweden)

    Thomas M Carmen

    2008-06-01

    Full Text Available Abstract Background Protozoan parasites of the genus Leishmania are causative agents of a diverse spectrum of human diseases collectively known as leishmaniasis. These eukaryotic pathogens that diverged early from the main eukaryotic lineage possess a number of unusual genomic, molecular and biochemical features. The completion of the genome projects for three Leishmania species has generated invaluable information enabling a direct analysis of genome structure and organization. Results By using DNA macroarrays, made with Leishmania infantum genomic clones and hybridized with total DNA from the parasite, we identified a clone containing a repeated sequence. An analysis of the recently completed genome sequence of L. infantum, using this repeated sequence as bait, led to the identification of a new class of repeated elements that are interspersed along the different L. infantum chromosomes. These elements turned out to be homologues of SIDER2 sequences, which were recently identified in the Leishmania major genome; thus, we adopted this nomenclature for the Leishmania elements described herein. Since SIDER2 elements are very heterogeneous in sequence, their precise identification is rather laborious. We have characterized 54 LiSIDER2 elements in chromosome 32 and 27 ones in chromosome 20. The mean size for these elements is 550 bp and their sequence is G+C rich (mean value of 66.5%. On the basis of sequence similarity, these elements can be grouped in subfamilies that show a remarkable relationship of proximity, i.e. SIDER2s of a given subfamily locate close in a chromosomal region without intercalating elements. For comparative purposes, we have identified the SIDER2 elements existing in L. major and Leishmania braziliensis chromosomes 32. While SIDER2 elements are highly conserved both in number and location between L. infantum and L. major, no such conservation exists when comparing with SIDER2s in L. braziliensis chromosome 32. Conclusion

  3. Methane Seeps in the Gulf of Mexico: repeat acoustic surveying shows highly temporally and spatially variable venting

    Science.gov (United States)

    Beaumont, B. C.; Raineault, N.

    2016-02-01

    Scientists have recognized that natural seeps account for a large amount of methane emissions. Despite their widespread occurrence in areas like the Gulf of Mexico, little is known about the temporal variability and site-scale spatial variability of venting over time. We used repeat acoustic surveys to compare multiple days of seep activity and determine the changes in the locus of methane emission and plume height. The Sleeping Dragon site was surveyed with an EM302 multibeam sonar on three consecutive days in 2014 and 4 days within one week in 2015. The data revealed three distinctive plume regions. The locus of venting varied by 10-60 meters at each site. The plume that exhibited the least spatial variability in venting, was also the most temporally variable. This seep was present in one-third of survey dates in 2014 and three quarters of survey dates in 2015, showing high day-to-day variability. The plume height was very consistent for this plume, whereas the other plumes were more consistent temporally, but varied in maximum plume height detection by 25-85 m. The single locus of emission at the site that had high day-to-day variability may be due to a single conduit for methane release, which is sometimes closed off by carbonate or clathrate hydrate formation. In addition to day-to-day temporal variability, the locus of emission at one site was observed to shift from a point-source in 2014 to a diffuse source in 2015 at a nearby location. ROV observations showed that one of the seep sites that closed off temporarily, experienced an explosive breakthrough of gas, releasing confined methane and blowing out rock. The mechanism that causes on/off behavior of certain plumes, combined with the spatial variability of the locus of methane release shown in this study may point to carbonate or hydrate formation in the seep plumbing system and should be further investigated.

  4. Novel Luminex Assay for Telomere Repeat Mass Does Not Show Well Position Effects Like qPCR.

    Directory of Open Access Journals (Sweden)

    Muhammad G Kibriya

    Full Text Available Telomere length is a potential biomarker of aging and risk for age-related diseases. For measurement of relative telomere repeat mass (TRM, qPCR is typically used primarily due to its low cost and low DNA input. But the position of the sample on a plate often impacts the qPCR-based TRM measurement. Recently we developed a novel, probe-based Luminex assay for TRM that requires ~50ng DNA and involves no DNA amplification. Here we report, for the first time, a comparison among TRM measurements obtained from (a two singleplex qPCR assays (using two different primer sets, (b a multiplex qPCR assay, and (c our novel Luminex assay. Our comparison is focused on characterizing the effects of sample positioning on TRM measurement. For qPCR, DNA samples from two individuals (K and F were placed in 48 wells of a 96-well plate. For each singleplex qPCR assay, we used two plates (one for Telomere and one for Reference gene. For the multiplex qPCR and the Luminex assay, the telomere and the reference genes were assayed from the same well. The coefficient of variation (CV of the TRM for Luminex (7.2 to 8.4% was consistently lower than singleplex qPCR (11.4 to 14.9% and multiplex qPCR (19.7 to 24.3%. In all three qPCR assays the DNA samples in the left- and right-most columns showed significantly lower TRM than the samples towards the center, which was not the case for the Luminex assay (p = 0.83. For singleplex qPCR, 30.5% of the variation in TL was explained by column-to-column variation and 0.82 to 27.9% was explained by sample-to-sample variation. In contrast, only 5.8% of the variation in TRM for the Luminex assay was explained by column-to column variation and 50.4% was explained by sample-to-sample variation. Our novel Luminex assay for TRM had good precision and did not show the well position effects of the sample that were seen in all three of the qPCR assays that were tested.

  5. The repeat domain of the type III effector protein PthA shows a TPR-like structure and undergoes conformational changes upon DNA interaction.

    Science.gov (United States)

    Murakami, Mário Tyago; Sforça, Mauricio Luis; Neves, Jorge Luiz; Paiva, Joice Helena; Domingues, Mariane Noronha; Pereira, André Luiz Araujo; Zeri, Ana Carolina de Mattos; Benedetti, Celso Eduardo

    2010-12-01

    Many plant pathogenic bacteria rely on effector proteins to suppress defense and manipulate host cell mechanisms to cause disease. The effector protein PthA modulates the host transcriptome to promote citrus canker. PthA possesses unusual protein architecture with an internal region encompassing variable numbers of near-identical tandem repeats of 34 amino acids termed the repeat domain. This domain mediates protein-protein and protein-DNA interactions, and two polymorphic residues in each repeat unit determine DNA specificity. To gain insights into how the repeat domain promotes protein-protein and protein-DNA contacts, we have solved the structure of a peptide corresponding to 1.5 units of the PthA repeat domain by nuclear magnetic resonance (NMR) and carried out small-angle X-ray scattering (SAXS) and spectroscopic studies on the entire 15.5-repeat domain of PthA2 (RD2). Consistent with secondary structure predictions and circular dichroism data, the NMR structure of the 1.5-repeat peptide reveals three α-helices connected by two turns that fold into a tetratricopeptide repeat (TPR)-like domain. The NMR structure corroborates the theoretical TPR superhelix predicted for RD2, which is also in agreement with the elongated shape of RD2 determined by SAXS. Furthermore, RD2 undergoes conformational changes in a pH-dependent manner and upon DNA interaction, and shows sequence similarities to pentatricopeptide repeat (PPR), a nucleic acid-binding motif structurally related to TPR. The results point to a model in which the RD2 structure changes its compactness as it embraces the DNA with the polymorphic diresidues facing the interior of the superhelix oriented toward the nucleotide bases.

  6. Plasmodium falciparum field isolates from areas of repeated emergence of drug resistant malaria show no evidence of hypermutator phenotype.

    Science.gov (United States)

    Brown, Tyler S; Jacob, Christopher G; Silva, Joana C; Takala-Harrison, Shannon; Djimdé, Abdoulaye; Dondorp, Arjen M; Fukuda, Mark; Noedl, Harald; Nyunt, Myaing Myaing; Kyaw, Myat Phone; Mayxay, Mayfong; Hien, Tran Tinh; Plowe, Christopher V; Cummings, Michael P

    2015-03-01

    Multiple transcontinental waves of drug resistance in Plasmodium falciparum have originated in Southeast Asia before spreading westward, first into the rest of Asia and then to sub-Saharan Africa. In vitro studies have suggested that hypermutator P. falciparum parasites may exist in Southeast Asia and that an increased rate of acquisition of new mutations in these parasites may explain the repeated emergence of drug resistance in Southeast Asia. This study is the first to test the hypermutator hypothesis using field isolates. Using genome-wide SNP data from human P. falciparum infections in Southeast Asia and West Africa and a test for relative rate differences we found no evidence of increased relative substitution rates in P. falciparum isolates from Southeast Asia. Instead, we found significantly increased substitution rates in Mali and Bangladesh populations relative to those in populations from Southeast Asia. Additionally we found no association between increased relative substitution rates and parasite clearance following treatment with artemisinin derivatives.

  7. [A case of bronchial foreign body due to citrus fruit seed aspiration showing multiple pulmonary infiltration repeatedly].

    Science.gov (United States)

    Morimatsu, Yoshitaka; Aoki, Yuka; Mizoguchi, Yusuke; Kitasato, Hirohiko; Aizawa, Hisamichi

    2005-12-01

    We report a case of a bronchial foreign body in a 76-year-old citrus fruit farmer. The patient was detected patchy infiltration (ground-glass attenuation) of the right upper lung field on the chest X-ray on Dec. 26th, 2003. The shadow tended to disappear after treatment with antibiotics. The same shadow was detected again 10 months later and the patient underwent a bronchoscopic examination. A foreign body was found lodged in the center of the right upper bronchus, associated with bronchial stenosis due to mucosal edema. The abnormal shadow disappeared after the foreign body, which we decided was a citrus fruit seed, was removed. From the time course of the present illness and a retrospective evaluation of previous chest X-rays, the patient had aspirated the foreign body 18 months prior to his admission for bronchoscopy. We should be careful of the possibility of foreign bodies even when the elderly do not present a history of foreign body aspiration. It is important to consider the possibility of a bronchial foreign body in patients with repeated pneumonia, and to perform bronchoscopy aggressively.

  8. 2015 Indonesian fire activity and smoke pollution show persistent non-linear sensitivity to El Niño-induced drought

    Science.gov (United States)

    Field, R. D.; van der Werf, G.; Fanin, T.; Fetzer, E. J.; Fuller, R. A.; Jethva, H. T.; Levy, R. C.; Livesey, N. J.; Luo, M.; Torres, O.; Worden, H. M.

    2016-12-01

    The 2015 fire season and related smoke pollution in Indonesia was more severe than the major 2006 episode, making it the most severe season observed by the NASA Earth Observing System satellites that go back to the early 2000s, namely active fire detections from the Terra and Aqua Moderate Resolution Imaging Spectroradiometers (MODIS), MODIS aerosol optical depth, Terra Measurement of Pollution in the Troposphere (MOPITT) carbon monoxide (CO), Aqua Atmospheric Infrared Sounder (AIRS) CO, Aura Ozone Monitoring Instrument (OMI) aerosol index, and Aura Microwave Limb Sounder (MLS) CO. The MLS CO in the upper troposphere showed a plume of pollution stretching from East Africa to the western Pacific Ocean that persisted for two months. Longer-term records of airport visibility in Sumatra and Kalimantan show that 2015 ranked after 1997 and alongside 1991 and 1994 as among the worst episodes on record. Analysis of yearly dry season rainfall from the Tropical Rainfall Measurement Mission (TRMM) and rain gauges shows that, due to the continued use of fire to clear and prepare land on degraded peat, the Indonesian fire environment continues to have non-linear sensitivity to dry conditions during prolonged periods with less than 4mm/day of precipitation, and this sensitivity appears to have increased over Kalimantan. Without significant reforms in land use and the adoption of early warning triggers tied to precipitation forecasts, these intense fire episodes will re-occur during future droughts, usually associated with El Niño events. Characterization of this signifcant event was only possible with EOS data, from the A-train instruments especially.

  9. A theoretical drought classification method for the multivariate drought index based on distribution properties of standardized drought indices

    Science.gov (United States)

    Hao, Zengchao; Hao, Fanghua; Singh, Vijay P.; Xia, Youlong; Ouyang, Wei; Shen, Xinyi

    2016-06-01

    Drought indices have been commonly used to characterize different properties of drought and the need to combine multiple drought indices for accurate drought monitoring has been well recognized. Based on linear combinations of multiple drought indices, a variety of multivariate drought indices have recently been developed for comprehensive drought monitoring to integrate drought information from various sources. For operational drought management, it is generally required to determine thresholds of drought severity for drought classification to trigger a mitigation response during a drought event to aid stakeholders and policy makers in decision making. Though the classification of drought categories based on the univariate drought indices has been well studied, drought classification method for the multivariate drought index has been less explored mainly due to the lack of information about its distribution property. In this study, a theoretical drought classification method is proposed for the multivariate drought index, based on a linear combination of multiple indices. Based on the distribution property of the standardized drought index, a theoretical distribution of the linear combined index (LDI) is derived, which can be used for classifying drought with the percentile approach. Application of the proposed method for drought classification of LDI, based on standardized precipitation index (SPI), standardized soil moisture index (SSI), and standardized runoff index (SRI) is illustrated with climate division data from California, United States. Results from comparison with the empirical methods show a satisfactory performance of the proposed method for drought classification.

  10. Nonintrusive Field Experiments Show Different Plant Responses to Warming and Drought Among Sites, Seasons, and Species in a North-South European Gradient

    NARCIS (Netherlands)

    Peñuelas, J.; Gordon, C.; Llorens, L.; Nielsen, T.; Tietema, A.; Beier, J.C.; Bruna, P.; Emmett, B.; Estiarte, M.; Gorissen, A.

    2004-01-01

    We used a novel, nonintrusive experimental system to examine plant responses to warming and drought across a climatic and geographical latitudinal gradient of shrubland ecosystems in four sites from northern to southern Europe (UK, Denmark, The Netherlands, and Spain). In the first two years of expe

  11. Nonintrusive Field Experiments Show Different Plant Responses to Warming and Drought Among Sites, Seasons, and Species in a North-South European Gradient

    NARCIS (Netherlands)

    Peñuelas, J.; Gordon, C.; Llorens, L.; Nielsen, T.; Tietema, A.; Beier, J.C.; Bruna, P.; Emmett, B.; Estiarte, M.; Gorissen, A.

    2004-01-01

    We used a novel, nonintrusive experimental system to examine plant responses to warming and drought across a climatic and geographical latitudinal gradient of shrubland ecosystems in four sites from northern to southern Europe (UK, Denmark, The Netherlands, and Spain). In the first two years of

  12. The European Drought Observatory (EDO) - A European Contribution to a Global Drought Information System (GDIS)

    Science.gov (United States)

    Vogt, J.; Sepulcre, G.; De Jager, A.; Magni, D.; Valentini, L.; Russo, S.; Micale, F.; Barbosa, P.

    2013-12-01

    Europe has repeatedly been affected by droughts, resulting in considerable ecological and economic damage and climate change studies indicate a trend towards increasing climate variability most likely resulting in more frequent drought occurrences also in Europe. Against this background, the European Commission's Joint Research Centre (JRC) is developing methods and tools for assessing, monitoring and forecasting droughts in Europe and develops a European Drought Observatory (EDO) to complement and integrate national activities with a European view. At the core of EDO is a portal, including a map viewer, a metadata catalogue, a media-monitor and analysis tools. Underlying data stem from ground and satellite observations as well as from distributed hydrological models and are stored in a relational database. Through the map viewer Europe-wide up-to-date information on the occurrence and severity of droughts is presented, complemented by more detailed information from regional, national and local observatories through OGC compliant web-mapping services. The continent-wide meteorological, soil moisture-related and vegetation-related indicators are then integrated into a combined indicator showing different alert levels targeted specifically to decision makers in water and land management. Finally, time series of historical maps as well as graphs of the temporal evolution of drought indices for individual grid cells in Europe can be retrieved and analysed. On-going work is focusing on developing reliable medium and long-range probabilistic as well as seasonal drought forecasts, the analysis of climate change impacts on drought occurrence, duration and severity and the assessment of current and future drought hazard and risk. In addition, remote sensing-based water-stress indicators from geostationary satellite data (e.g., MSG SEVIRI) are developed in order to complement the available information. The further development of EDO as part of a Global Drought Information

  13. Monitoring vegetation responses to drought -- linking Remotely-sensed Drought Indices with Meteorological drought indices

    Science.gov (United States)

    Wang, H.; Lin, H.; Liu, D.

    2013-12-01

    Abstract: Effectively monitoring vegetation drought is of great significance in ecological conservation and agriculture irrigation at the regional scale. Combining meteorological drought indices with remotely sensed drought indices can improve tracking vegetation dynamic under the threat of drought. This study analyzes the dynamics of spatially-defined Temperature Vegetation Dryness Index (TVDI) and temporally-defined Vegetation Health Index (VHI) from remotely sensed NDVI and LST datasets in the dry spells in Southwest China. We analyzed the correlation between remotely sensed drought indices and meteorological drought index of different time scales. The results show that TVDI was limited by the spatial variations of LST and NDVI, while VHI was limited by the temporal variations of LST and NDVI. Station-based buffering analysis indicates that the extracted remotely sensed drought indices and Standard Precipitation Index (SPI) could reach stable correlation with buffering radius larger than 35 km. Three factors affect the spatiotemporal relationship between remotely sensed drought indices and SPI: i) different vegetation types; ii) the timescale of SPI; and iii) remote sensing data noise. Vegetation responds differently to meteorological drought at various time scales. The correlation between SPI6 and VHI is more significant than that between SPI6 and TVDI. Spatial consistency between VHI and TVDI varies with drought aggravation. In early drought period from October to December, VHI and TVDI show limited consistency due to the low quality of remotely sensed images. The study helps to improve monitoring vegetation drought using both meteorological drought indices and remotely sensed drought indices.

  14. Global patterns of drought recovery

    Energy Technology Data Exchange (ETDEWEB)

    Schwalm, Christopher R.; Anderegg, William; Michalak, A. M.; Fisher, J.B.; Biondi, Franco; Koch, George; Litvak, Marcy; Ogle, Kiona; Shaw, John D.; Wolf, Adam; Huntzinger, Deborah; Schaefer, Kevin; Cook, R. B.; Wei, Yaxing; Fang, Yuanyuan; Hayes, Daniel J.; Huang, Maoyi; Jain, Atul K.; Tian, Hanqin

    2017-08-09

    Drought is a recurring multi-factor phenomenon with major impacts on natural and human systems1-3. Drought is especially important for land carbon sink variability, influencing climate regulation of the terrestrial biosphere4. While 20th Century trends in drought regime are ambiguous, “more extreme extremes” as well as more frequent and severe droughts3,7 are expected in the 21st Century. Recovery time, the length of time an ecosystem requires to revert to its pre-drought functional state, is a critical metric of drought impact. Yet the spatiotemporal patterning and controls of drought recovery are largely unknown. Here we use three distinct global datasets of gross primary productivity to show that across diverse terrestrial ecosystems drought recovery times are driven by biological productivity and biodiversity, with drought length and severity of secondary importance. Recovery time, especially for extreme droughts, and the areal extent of ecosystems in recovery from drought generally increase over the 20th Century, supporting an increase globally in drought impact8. Our results indicate that if future Anthropocene droughts become more widespread as expected, that droughts will become more frequent relative to recovery time. This increases the risk of entering a new regime where vegetation never recovers to its original state and widespread degradation of the land carbon sink ensues.

  15. Mice repeatedly exposed to Group-A β-Haemolytic Streptococcus show perseverative behaviors, impaired sensorimotor gating, and immune activation in rostral diencephalon.

    Science.gov (United States)

    Macrì, Simone; Ceci, Chiara; Onori, Martina Proietti; Invernizzi, Roberto William; Bartolini, Erika; Altabella, Luisa; Canese, Rossella; Imperi, Monica; Orefici, Graziella; Creti, Roberta; Margarit, Immaculada; Magliozzi, Roberta; Laviola, Giovanni

    2015-08-25

    Repeated exposure to Group-A β-Haemolytic Streptococcus (GAS) may constitute a vulnerability factor in the onset and course of pediatric motor disturbances. GAS infections/colonization can stimulate the production of antibodies, which may cross the blood brain barrier, target selected brain areas (e.g. basal ganglia), and exacerbate motor alterations. Here, we exposed developing SJL male mice to four injections with a GAS homogenate and evaluated the following domains: motor coordination; general locomotion; repetitive behaviors; perseverative responses; and sensorimotor gating (pre-pulse inhibition, PPI). To demonstrate that behavioral changes were associated with immune-mediated brain alterations, we analyzed, in selected brain areas, the presence of infiltrates and microglial activation (immunohistochemistry), monoamines (HPLC), and brain metabolites (in vivo Magnetic Resonance Spectroscopy). GAS-exposed mice showed increased repetitive and perseverative behaviors, impaired PPI, and reduced concentrations of serotonin in prefrontal cortex, a brain area linked to the behavioral domains investigated, wherein they also showed remarkable elevations in lactate. Active inflammatory processes were substantiated by the observation of infiltrates and microglial activation in the white matter of the anterior diencephalon. These data support the hypothesis that repeated GAS exposure may elicit inflammatory responses in brain areas involved in motor control and perseverative behavior, and result in phenotypic abnormalities.

  16. The canine prostate cancer cell line CHP-1 shows over-expression of the co-chaperone small glutamine-rich tetratricopeptide repeat-containing protein α.

    Science.gov (United States)

    Azakami, D; Nakahira, R; Kato, Y; Michishita, M; Kobayashi, M; Onozawa, E; Bonkobara, M; Kobayashi, M; Takahashi, K; Watanabe, M; Ishioka, K; Sako, T; Ochiai, K; Omi, T

    2017-06-01

    Although androgen therapy resistance and poor clinical outcomes are seen in most canine prostate cancer cases, there are only a few tools for analysing canine prostate cancer by using a cell biological approach. Therefore, to evaluate androgen-independent neoplastic cell growth, a new canine prostate cancer cell line (CHP-1) was established in this study. CHP-1 over-expressed the co-chaperone small glutamine-rich tetratricopeptide repeat-containing protein α (SGTA), which is over-expressed in human androgen-independent prostate cancer. The CHP-1 xenograft also showed SGTA over-expression. Although CHP-1 shows poor androgen receptor (AR) signalling upon dihydrotestosterone stimulation, forced expression of AR enabled evaluation of AR signalling. Taken together, these results suggest that CHP-1 will be a useful model for investigating the pathogenesis of androgen-dependent and androgen-independent canine prostate cancer. © 2016 John Wiley & Sons Ltd.

  17. On The Repeater Control to Achieve Goods Any Show Effect%Repeater控件实现商品的任何展示效果的研究

    Institute of Scientific and Technical Information of China (English)

    王得燕; 肖颖

    2011-01-01

    DataGrid、DataList和Repeater三个控件是ASP.NET的重要数据控件,通过数据源的设置。均可以用来显示数据,被大量用于WEB网页的设计过程中。文章对三个控件的异同做了研究,对看起来份量最轻但其实性能最好的Repeater控件进行深入研究,给出实现各种商品展示效果的程序设计方法。%Data Grid, Data List and Repeater are three important controls for ASP. NET data controls. By setting the data source, they can be used to display data and WEB pages design process. This article made some comparison on the similarities and differences between the three controls, and studied the Repeater control deeply and gave programs that achieve Any Show Effect of goods.

  18. Nonintrusive field experiments show different plant responses to warming and drought among sites, seasons, and species in a north-south European gradient

    DEFF Research Database (Denmark)

    Penuelas, J.; Gordon, C.; Llorens, L.;

    2004-01-01

    of experimentation reported here, we measured plant cover and biomass by the pinpoint method, plant (14)C uptake, stem and shoot growth, flowering, leaf chemical concentration, litterfall, and herbivory damage in the dominant plant species of each site. The two years of approximately PC experimental warming induced......-limited. In the water-stressed southern site, there was no increase in total aboveground plant biomass growth as expected since warming increases water loss, and temperatures in those ecosystems are already close to the optimum for photosynthesis. The southern site presented instead the most negative response......We used a novel, nonintrusive experimental system to examine plant responses to warming and drought across a climatic and geographical latitudinal gradient of shrubland ecosystems in four sites from northern to southern Europe (UK, Denmark, The Netherlands, and Spain). In the first two years...

  19. 基于标准化降水蒸散指数的中国干旱趋势研究%Standardized precipitation evapotranspiration index shows drought trends in China

    Institute of Scientific and Technical Information of China (English)

    李伟光; 易雪; 侯美亭; 陈汇林; 陈珍莉

    2012-01-01

    Standardized precipitation evapotranspiration index (SPEI), calculated from the difference between potential evapotranspiration and precipitation, showed dry and wet deviations from normal conditions. This is generally used as an indicator for drought evolution trends in drought assessments, water resources management and other fields of hydrology. Using monthly mean surface air temperature and precipitation collected from 160 meteorological stations across China for 1951—2009. Spatial distributions of seasonal drought trends and frequencies of extreme drought events were analyzed via SPEI. The results showed drying trends across the whole of China. The most significant drought was in the west, north and northeast of China. It was, however, wet in some regions of northern Xinjiang and the border regions of Sichuan and Yunnan. Drying trends existed for all four seasons, and were more obvious in spring and autumn. Summer was always dry in the last 15 years, although with a drying trend insignificant at the 0.05 level. Furthermore, the frequency of extreme drought increased significantly. Significant trends in temperature increase along with moderate trends in precipitation decline were noted for many stations in the northeast and north of China. The combined effects of precipitation and temperature caused significant droughts in the country. In the Sichuan Basin, precipitation significantly decreased with no significant change in temperature. Drought in Sichuan Basin was largely attributed to decreasing precipitation. In recent years, extreme drought events increased with decreasing frequencies of precipitation events in many areas of China. Widespread drought trends and significant increases in extreme drought events probably hindered China's economic development. SPEI-detected drought trends were mostly consistent with observed droughts in China, indicating that SPEI was an ideal index for monitoring drying trends.%标准化降水蒸散指数(SPEI)通过标准

  20. Drought and groundwater management

    DEFF Research Database (Denmark)

    Amundsen, Eirik S; Jensen, Frank

    This paper considers the problem of a water management authority faced with the threat of a drought that hits at an uncertain date. Three management policies are investigated: i) a laissez-faire (open-access) policy of automatic adjustment through a zero marginal private net benefit condition, ii......) a policy of optimal dynamic management ignoring the threat of the drought and relying on automatic adjustments through a zero marginal social net benefit condition, iii) an economically optimal dynamic policy taking account of the threat of a drought. In particular, we show that the optimal pre......-drought steady-state equilibrium stock size of water under policy iii) is smaller than under policy ii) and, hence, a precautionary stock size should not be built up prior to the drought....

  1. The German drought monitor

    Science.gov (United States)

    Zink, Matthias; Samaniego, Luis; Kumar, Rohini; Thober, Stephan; Mai, Juliane; Schäfer, David; Marx, Andreas

    2016-07-01

    The 2003 drought event in Europe had major implications on many societal sectors, including energy production, health, forestry and agriculture. The reduced availability of water accompanied by high temperatures led to substantial economic losses on the order of 1.5 Billion Euros, in agriculture alone. Furthermore, soil droughts have considerable impacts on ecosystems, forest fires and water management. Monitoring soil water availability in near real-time and at high-resolution, i.e., 4 × 4 km2, enables water managers to mitigate the impact of these extreme events. The German drought monitor was established in 2014 as an online platform. It uses an operational modeling system that consists of four steps: (1) a daily update of observed meteorological data by the German Weather Service, with consistency checks and interpolation; (2) an estimation of current soil moisture using the mesoscale hydrological model; (3) calculation of a quantile-based soil moisture index (SMI) based on a 60 year data record; and (4) classification of the SMI into five drought classes ranging from abnormally dry to exceptional drought. Finally, an easy to understand map is produced and published on a daily basis on www.ufz.de/droughtmonitor. Analysis of the ongoing 2015 drought event, which garnered broad media attention, shows that 75% of the German territory underwent drought conditions in July 2015. Regions such as Northern Bavaria and Eastern Saxony, however, have been particularly prone to drought conditions since autumn 2014. Comparisons with historical droughts show that the 2015 event is amongst the ten most severe drought events observed in Germany since 1954 in terms of its spatial extent, magnitude and duration.

  2. Relationship Between Physiological-biochemical Changes Under Drought Stress and Drought Resistance in Ramie

    Institute of Scientific and Technical Information of China (English)

    JIE Yu-cheng; HUANG Pi-sheng; LI Zong-dao

    2001-01-01

    A study on the physiological-biochemical changes of different ramie(Boehmeria Jacq. ) varieties under drought stress was carried out, the results showed that relative water contents(RWC) decreased and RPP increased with the increase of drought stress. Compared with drought sensitive varieties, drought resistant varieties had higher RWC in leaves but lower RPP. Peroxidase activity of drought-resistance varieties changed from low to high whereas sensitive ones changed in opposite direction. Proline contents of drought sensitive varieties was higher than those of drought resistant ones under a certain degree drought stress. Proline accumulation in drought resistant varieties was faster than that in drought sensitive ones under serious drought stress.MDA contents in leaf was increased under drought stress. MDA contents increased slowly in resistant varieties while that increased rapidly in sensitive ones.

  3. Drought Risk Identification: Early Warning System of Seasonal Agrometeorological Drought

    Science.gov (United States)

    Dalecios, Nicolas; Spyropoulos, Nicos V.; Tarquis, Ana M.

    2014-05-01

    By considering drought as a hazard, drought types are classified into three categories, namely meteorological or climatological, agrometeorological or agricultural and hydrological drought and as a fourth class the socioeconomic impacts can be considered. This paper addresses agrometeorological drought affecting agriculture within the risk management framework. Risk management consists of risk assessment, as well as a feedback on the adopted risk reduction measures. And risk assessment comprises three distinct steps, namely risk identification, risk estimation and risk evaluation. This paper deals with the quantification and monitoring of agrometeorological drought, which constitute part of risk identification. For the quantitative assessment of agrometeorological or agricultural drought, as well as the computation of spatiotemporal features, one of the most reliable and widely used indices is applied, namely the Vegetation Health Index (VHI). The computation of VHI is based on satellite data of temperature and the Normalized Difference Vegetation Index (NDVI). The spatiotemporal features of drought, which are extracted from VHI are: areal extent, onset and end time, duration and severity. In this paper, a 20-year (1981-2001) time series of NOAA/AVHRR satellite data is used, where monthly images of VHI are extracted. Application is implemented in Thessaly, which is the major agricultural region of Greece characterized by vulnerable and drought-prone agriculture. The results show that every year there is a seasonal agrometeorological drought with a gradual increase in the areal extent and severity with peaks appearing usually during the summer. Drought monitoring is conducted by monthly remotely sensed VHI images. Drought early warning is developed using empirical relationships of severity and areal extent. In particular, two second-order polynomials are fitted, one for low and the other for high severity drought, respectively. The two fitted curves offer a seasonal

  4. New species of Ehrlichia isolated from Rhipicephalus (Boophilus microplus shows an ortholog of the E. canis major immunogenic glycoprotein gp36 with a new sequence of tandem repeats

    Directory of Open Access Journals (Sweden)

    Cruz Alejandro Cabezas

    2012-12-01

    Full Text Available Abstract Background Ehrlichia species are the etiological agents of emerging and life-threatening tick-borne human zoonoses that inflict serious and fatal infections in companion animals and livestock. The aim of this paper was to phylogeneticaly characterise a new species of Ehrlichia isolated from Rhipicephalus (Boophilus microplus from Minas Gerais, Brazil. Methods The agent was isolated from the hemolymph of Rhipicephalus (B. microplus engorged females that had been collected from naturally infested cattle in a farm in the state of Minas Gerais, Brazil. This agent was then established and cultured in IDE8 tick cells. The molecular and phylogenetic analysis was based on 16S rRNA, groEL, dsb, gltA and gp36 genes. We used the maximum likelihood method to construct the phylogenetic trees. Results The phylogenetic trees based on 16S rRNA, groEL, dsb and gltA showed that the Ehrlichia spp isolated in this study falls in a clade separated from any previously reported Ehrlichia spp. The molecular analysis of the ortholog of gp36, the major immunoreactive glycoproteins in E. canis and ortholog of the E. chaffeensis gp47, showed a unique tandem repeat of 9 amino acids (VPAASGDAQ when compared with those reported for E. canis, E. chaffeensis and the related mucin-like protein in E. ruminantium. Conclusions Based on the molecular and phylogenetic analysis of the 16S rRNA, groEL, dsb and gltA genes we concluded that this tick-derived microorganism isolated in Brazil is a new species, named E. mineirensis (UFMG-EV, with predicted novel antigenic properties in the gp36 ortholog glycoprotein. Further studies on this new Ehrlichia spp should address questions about its transmissibility by ticks and its pathogenicity for mammalian hosts.

  5. Tomato PYR/PYL/RCAR abscisic acid receptors show high expression in root, differential sensitivity to the abscisic acid agonist quinabactin, and the capability to enhance plant drought resistance.

    Science.gov (United States)

    González-Guzmán, Miguel; Rodríguez, Lesia; Lorenzo-Orts, Laura; Pons, Clara; Sarrión-Perdigones, Alejandro; Fernández, Maria A; Peirats-Llobet, Marta; Forment, Javier; Moreno-Alvero, Maria; Cutler, Sean R; Albert, Armando; Granell, Antonio; Rodríguez, Pedro L

    2014-08-01

    Abscisic acid (ABA) plays a crucial role in the plant's response to both biotic and abiotic stress. Sustainable production of food faces several key challenges, particularly the generation of new varieties with improved water use efficiency and drought tolerance. Different studies have shown the potential applications of Arabidopsis PYR/PYL/RCAR ABA receptors to enhance plant drought resistance. Consequently the functional characterization of orthologous genes in crops holds promise for agriculture. The full set of tomato (Solanum lycopersicum) PYR/PYL/RCAR ABA receptors have been identified here. From the 15 putative tomato ABA receptors, 14 of them could be grouped in three subfamilies that correlated well with corresponding Arabidopsis subfamilies. High levels of expression of PYR/PYL/RCAR genes was found in tomato root, and some genes showed predominant expression in leaf and fruit tissues. Functional characterization of tomato receptors was performed through interaction assays with Arabidopsis and tomato clade A protein phosphatase type 2Cs (PP2Cs) as well as phosphatase inhibition studies. Tomato receptors were able to inhibit the activity of clade A PP2Cs differentially in an ABA-dependent manner, and at least three receptors were sensitive to the ABA agonist quinabactin, which inhibited tomato seed germination. Indeed, the chemical activation of ABA signalling induced by quinabactin was able to activate stress-responsive genes. Both dimeric and monomeric tomato receptors were functional in Arabidopsis plant cells, but only overexpression of monomeric-type receptors conferred enhanced drought resistance. In summary, gene expression analyses, and chemical and transgenic approaches revealed distinct properties of tomato PYR/PYL/RCAR ABA receptors that might have biotechnological implications.

  6. Adaptive strategies against drought stress of six plant species with different growth forms from karst habitats of southwestern China

    Science.gov (United States)

    Liu, C.; Guo, K.; Liu, Y.

    2012-04-01

    Frequent temporary drought in the rain season, as well as long-term drought in the dry season, is one of the most important factors limiting the survival and growth of plants in the harsh karst habitats of southwestern China. The morphological and physiological responses to drought stress of six native woody plant species were investigated under both temporary and prolonged drought stress. The six plant species included Pyracantha fortuneana (evergreen shrub), Rosa cymosa (deciduous shrub), Cinnamomum bodinieri (evergreen tree), and other three deciduous trees, Broussonetia papyrifera, Platycarya longipes and Pteroceltis tatarinowii. Under severe drought stress, the two shrubs with low leaf area ratio (LAR) maintained higher water status, higher photosynthetic capacity and larger percent biomass increase than the most of the trees, owing to their lower specific leaf area, higher intrinsic water use efficiency and thermal dissipation, and higher capacities of osmotic adjustment and antioxidant protection. The evergreen tree, C. bodinieri, exhibited small decrease of water potential and maintained higher leaf mass ratio (LMR) and LAR than the deciduous species under moderate drought stress, due to the high proline accumulation and high activities of antioxidant enzymes. However, it showed high levels of cellular damages, very low photosynthetic capacity, and sharp decreases of water potential and biomass under severe drought stress. After rewatering, C. bodinieri showed a lower ability to recover from severe drought with the successive repeats of severe drought event. The three deciduous trees developed high root mass ratio for maximizing water uptake, and showed higher LAR and biomass than the two shrubs under well-watered condition. However, drought stress resulted in sharp decreases of biomass in the three deciduous trees, which were attributed to the large drought-induced decreases of LMR, LAR and gas exchange. Under drought conditions, the deciduous trees

  7. Mice repeatedly exposed to Group-A β-Haemolytic Streptococcus show perseverative behaviors, impaired sensorimotor gating, and immune activation in rostral diencephalon

    OpenAIRE

    Simone Macrì; Chiara Ceci; Martina Proietti Onori; Roberto William Invernizzi; Erika Bartolini; Luisa Altabella; Rossella Canese; Monica Imperi; Graziella Orefici; Roberta Creti; Immaculada Margarit; Roberta Magliozzi; Giovanni Laviola

    2015-01-01

    Repeated exposure to Group-A β-Haemolytic Streptococcus (GAS) may constitute a vulnerability factor in the onset and course of pediatric motor disturbances. GAS infections/colonization can stimulate the production of antibodies, which may cross the blood brain barrier, target selected brain areas (e.g. basal ganglia), and exacerbate motor alterations. Here, we exposed developing SJL male mice to four injections with a GAS homogenate and evaluated the following domains: motor coordination; gen...

  8. Identification of Drought-Responsive Genes and Validation for Drought Resistance in Rice

    OpenAIRE

    Batlang, Utlwang

    2010-01-01

    Drought stress was studied in rice (Oryza sativa) and maize (Zea mays) to identify drought-responsive genes and associated biological processes. One experiment with rice examined drought responses in vegetative and reproductive tissues and identified drought-responsive genes in each tissue type. The results showed that brief periods of acute drought stress at or near anthesis reduced photosynthetic efficiency and ultimately lowered grain yield. Yield was reduced as a result both of fewer spik...

  9. NMR shows hydrophobic interactions replace glycine packing in the triple helix at a natural break in the (Gly-X-Y)n repeat.

    Science.gov (United States)

    Li, Yingjie; Brodsky, Barbara; Baum, Jean

    2007-08-03

    Little is known about the structural consequences of the more than 20 breaks in the (Gly-X-Y)(n) repeating sequence found in the long triple helix domain of basement membrane type IV collagen. NMR triple resonance studies of doubly labeled residues within a set of collagen model peptides provide distance and dihedral angle restraints that allow determination of model structures of both a standard triple helix and of a triple helix with a break in solution. Although the standard triple helix cannot continue when Gly is not every third residue, the NMR data support rod-like molecules that have standard triple-helical structures on both sides of a well defined and highly localized perturbation. The GAAVM break region may be described as a "pseudo triple helix," because it preserves the standard one-residue stagger of the triple helix but introduces hydrophobic interactions at the position normally occupied by the much smaller and hydrogen-bonded Gly residue of the repeating (Gly-X-Y)(n) sequence. This structure provides a rationale for the consensus presence of hydrophobic residues in breaks of similar length and defines a novel variant of a triple helix that could be involved in recognition.

  10. Two novel DXZ4-associated long noncoding RNAs show developmental changes in expression coincident with heterochromatin formation at the human (Homo sapiens) macrosatellite repeat.

    Science.gov (United States)

    Figueroa, Debbie M; Darrow, Emily M; Chadwick, Brian P

    2015-12-01

    On the male X and female active X chromosome (Xa), the macrosatellite repeat (MSR) DXZ4 is packaged into constitutive heterochromatin characterized by CpG methylation and histone H3 tri-methylated at lysine-9 (H3K9me3). In contrast, DXZ4 on the female inactive X chromosome (Xi), is packaged into euchromatin, is bound by the architectural protein CCCTC-binding factor, and mediates Xi-specific long-range cis contact with similarly packaged tandem repeats on the Xi. In cancer, male DXZ4 can inappropriately revert to a Xi-like state and other MSRs have been reported to adopt alternate chromatin configurations in response to disease. Given this plasticity, we sought to identify factors that might control heterochromatin at DXZ4. In human embryonic stem cells, we found low levels of 5-hydroxymethylcytosine at DXZ4 and that this mark is lost upon differentiation as H3K9me3 is acquired. We identified two previously undescribed DXZ4 associated noncoding transcripts (DANT1 and DANT2) that are transcribed toward DXZ4 from promoters flanking the array. Each generates transcript isoforms that traverse the MSR. However, upon differentiation, enhancer of Zeste-2 silences DANT1, and DANT2 transcription terminates prior to entering DXZ4. These data support a model wherein DANT1 and/or DANT2 may function to regulate constitutive heterochromatin formation at this MSR.

  11. Two novel DXZ4-associated long noncoding RNAs show developmental changes in expression coincident with heterochromatin formation at the human (Homo sapiens) macrosatellite repeat

    Science.gov (United States)

    Figueroa, Debbie M.; Darrow, Emily M.; Chadwick, Brian P.

    2015-01-01

    On the male X and female active X chromosome (Xa), the macrosatellite repeat (MSR) DXZ4 is packaged into constitutive heterochromatin characterized by CpG methylation and histone H3 tri-methylated at lysine-9 (H3K9me3). In contrast, DXZ4 on the female inactive X chromosome (Xi), is packaged into euchromatin, is bound by the architectural protein CCCTC-binding factor, and mediates Xi-specific long-range cis contact with similarly packaged tandem repeats on the Xi. In cancer, male DXZ4 can inappropriately revert to a Xi-like state and other MSRs have been reported to adopt alternate chromatin configurations in response to disease. Given this plasticity, we sought to identify factors that might control heterochromatin at DXZ4. In human embryonic stem cells, we found low levels of 5-hydroxymethylcytosine at DXZ4, and that this mark is lost upon differentiation as H3K9me3 is acquired. We identified two previously undescribed DXZ4 associated non-coding transcripts (DANT1 and DANT2) that are transcribed towards DXZ4 from promoters flanking the array. Each generates transcript isoforms that traverse the MSR. However, upon differentiation, Enhancer of Zeste-2 silences DANT1, and DANT2 transcription terminates prior to entering DXZ4. These data support a model wherein DANT1 and/or DANT2 may function to regulate constitutive heterochromatin formation at this MSR. PMID:26188586

  12. Analysis of Droughts of Northwest of Iran Using the Reconnaissance Drought Index

    Directory of Open Access Journals (Sweden)

    behrouz hosseini

    2016-02-01

    second stage, the 64 candidate statistical distributions were fitted for the mentioned RDI’s of each station. The best statistical distribution was selected among the 64 candidate distributions. The best fitted distribution was identified by the chi-square criterion. The parameters of the distribution were estimated by the Maximum Likelihood Estimation (MLE scheme. Then 500 synthetic time series (each of them have the same number of observed data were generated employing the parent population parameters. The three main drought characteristics (namely duration, severity and magnitude were obtained for each of the mentioned artificial time series. The maximum values for each of the mentioned drought characteristic were selected for each year. Then, a new time series having the 500 elements were obtained by collecting the chosen values for each station. Once again the best distribution was selected for each series. Drought characteristics for different return periods (2, 10, 25, 50, 100 and 200 years were estimated for each station. Results and Discussion: Preliminary results indicated that a negative trend existed in annual rainfall time series for almost all of the stations. On the other hand, the pattern of monthly PET histograms were more or less similar for all of the selected stations. The peak of the PET was mainly observed in the hottest month of year, whereas the lowest value of the monthly PET belonged to the coldest month of year. The results showed that the amount of annual rainfall time series decreases sharply, after the year 1991. However, PET values significantly increase for all of the selected stations. After calculation of RDI values, the histogram of annual RDI’s was plotted against the year. This is repeated for all of the selected stations. Figure. 6 shows the mentioned diagram for Tabriz station as an example. In the mentioned Figure, negative values of RDI (shown by red bars indicated the drought years. A critical prolonged drought with a sixteen

  13. Hydrological drought typology: temperature-related drought types and associated societal impacts

    Directory of Open Access Journals (Sweden)

    A. F. Van Loon

    2014-09-01

    Full Text Available For drought management and prediction, knowledge of causing factors and socio-economic impacts of hydrological droughts is crucial. Propagation of meteorological conditions in the hydrological cycle results in different hydrological drought types that require separate analysis. In addition to the existing hydrological drought typology, we here define two new drought types related to snow and ice. A snowmelt drought is a deficiency in the snowmelt discharge peak in spring in snow-influenced basins and a glaciermelt drought is a deficiency in the glaciermelt discharge peak in summer in glacierised basins. In 21 catchments in Austria and Norway we studied the meteorological conditions in the seasons preceding and at the time of snowmelt and glaciermelt drought events. Snowmelt droughts in Norway were mainly controlled by below-average winter precipitation, while in Austria both temperature and precipitation played a role. For glaciermelt droughts the effect of below-normal summer temperature was dominant, both in Austria and Norway. Subsequently, we investigated the impacts of temperature-related drought types (i.e. snowmelt and glaciermelt drought, but also cold and warm snow season drought and rain-to-snow-season drought. In historical archives and drought databases for the US and Europe many impacts were found that can be attributed to these temperature-related hydrological drought types, mainly in the sectors agriculture and electricity production (hydropower. However, drawing conclusions on the frequency of occurrence of different drought types from reported impacts is difficult, mainly because of reporting biases and the inevitably limited spatial and temporal scales of the information. This study shows that the combination of quantitative analysis of causing factors and qualitative analysis of impacts of temperature-related droughts is a promising approach to identify relevant drought types in other regions, especially if more data on

  14. Drought assessment in the Dongliao River basin: traditional approaches vs. generalized drought assessment index based on water resources systems

    Science.gov (United States)

    Weng, B. S.; Yan, D. H.; Wang, H.; Liu, J. H.; Yang, Z. Y.; Qin, T. L.; Yin, J.

    2015-08-01

    Drought is firstly a resource issue, and with its development it evolves into a disaster issue. Drought events usually occur in a determinate but a random manner. Drought has become one of the major factors to affect sustainable socioeconomic development. In this paper, we propose the generalized drought assessment index (GDAI) based on water resources systems for assessing drought events. The GDAI considers water supply and water demand using a distributed hydrological model. We demonstrate the use of the proposed index in the Dongliao River basin in northeastern China. The results simulated by the GDAI are compared to observed drought disaster records in the Dongliao River basin. In addition, the temporal distribution of drought events and the spatial distribution of drought frequency from the GDAI are compared with the traditional approaches in general (i.e., standard precipitation index, Palmer drought severity index and rate of water deficit index). Then, generalized drought times, generalized drought duration, and generalized drought severity were calculated by theory of runs. Application of said runs at various drought levels (i.e., mild drought, moderate drought, severe drought, and extreme drought) during the period 1960-2010 shows that the centers of gravity of them all distribute in the middle reaches of Dongliao River basin, and change with time. The proposed methodology may help water managers in water-stressed regions to quantify the impact of drought, and consequently, to make decisions for coping with drought.

  15. Scientific Insights for Managing Droughts in California

    Science.gov (United States)

    Lund, J. R.; Medellin-Azuara, J.; Howitt, R. E.; MacEwan, D.; Sumner, D. A.

    2015-12-01

    Droughts stress water systems and provide important opportunities to learn about vulnerabilities and motivate improvements in water systems. Current and past droughts in California show that this highly-engineered system is highly robust and resilient to droughts, as agriculture and urban water needs are mostly fulfilled and recover quickly following drought. However, environmental systems remain highly vulnerable and have shown less resilience to drought, with each drought bringing additional native species closer to extinction, often with little recovery following the drought. This paper reviews the impacts of California's ongoing 4-year drought and its importance for better understanding its ecological and water supply systems, as well as motivating improvements in water management and scientific work.

  16. Evidence of Drought Stress Memory in the Facultative CAM, Aptenia cordifolia: Possible Role of Phytohormones.

    Directory of Open Access Journals (Sweden)

    Eva Fleta-Soriano

    Full Text Available Although plant responses to drought stress have been studied in detail in several plant species, including CAM plants, the occurrence of stress memory and possible mechanisms for its regulation are still very poorly understood. In an attempt to better understand the occurrence and possible mechanisms of regulation of stress memory in plants, we measured the concentrations of phytohormones in Aptenia cordifolia exposed to reiterated drought, together with various stress indicators, including leaf water contents, photosynthesis and mechanisms of photo- and antioxidant protection. Results showed that plants exposed to drought stress responded differently if previously challenged with a first drought. Gibberellin levels decreased upon exposure to the first drought and remained lower in double-stressed plants compared with those exposed to stress for the first time. In contrast, abscisic acid levels were higher in double- than single-stressed plants. This occurred in parallel with alterations in hydroperoxide levels, but not with malondialdehyde levels, thus suggesting an increased oxidation state that did not result in oxidative damage in double-stressed plants. It is concluded that (i drought stress memory occurs in double-stressed A. cordifolia plants, (ii both gibberellins and abscisic acid may play a role in plant response to repeated periods of drought, and (iii changes in abscisic acid levels in double-stressed plants may have a positive effect by modulating changes in the cellular redox state with a role in signalling, rather than cause oxidative damage to the cell.

  17. Evidence of Drought Stress Memory in the Facultative CAM, Aptenia cordifolia: Possible Role of Phytohormones.

    Science.gov (United States)

    Fleta-Soriano, Eva; Pintó-Marijuan, Marta; Munné-Bosch, Sergi

    2015-01-01

    Although plant responses to drought stress have been studied in detail in several plant species, including CAM plants, the occurrence of stress memory and possible mechanisms for its regulation are still very poorly understood. In an attempt to better understand the occurrence and possible mechanisms of regulation of stress memory in plants, we measured the concentrations of phytohormones in Aptenia cordifolia exposed to reiterated drought, together with various stress indicators, including leaf water contents, photosynthesis and mechanisms of photo- and antioxidant protection. Results showed that plants exposed to drought stress responded differently if previously challenged with a first drought. Gibberellin levels decreased upon exposure to the first drought and remained lower in double-stressed plants compared with those exposed to stress for the first time. In contrast, abscisic acid levels were higher in double- than single-stressed plants. This occurred in parallel with alterations in hydroperoxide levels, but not with malondialdehyde levels, thus suggesting an increased oxidation state that did not result in oxidative damage in double-stressed plants. It is concluded that (i) drought stress memory occurs in double-stressed A. cordifolia plants, (ii) both gibberellins and abscisic acid may play a role in plant response to repeated periods of drought, and (iii) changes in abscisic acid levels in double-stressed plants may have a positive effect by modulating changes in the cellular redox state with a role in signalling, rather than cause oxidative damage to the cell.

  18. The 2010 Amazon drought.

    Science.gov (United States)

    Lewis, Simon L; Brando, Paulo M; Phillips, Oliver L; van der Heijden, Geertje M F; Nepstad, Daniel

    2011-02-04

    In 2010, dry-season rainfall was low across Amazonia, with apparent similarities to the major 2005 drought. We analyzed a decade of satellite-derived rainfall data to compare both events. Standardized anomalies of dry-season rainfall showed that 57% of Amazonia had low rainfall in 2010 as compared with 37% in 2005 (≤-1 standard deviation from long-term mean). By using relationships between drying and forest biomass responses measured for 2005, we predict the impact of the 2010 drought as 2.2 × 10(15) grams of carbon [95% confidence intervals (CIs) are 1.2 and 3.4], largely longer-term committed emissions from drought-induced tree deaths, compared with 1.6 × 10(15) grams of carbon (CIs 0.8 and 2.6) for the 2005 event.

  19. Genetic differentiation revealed by selective loci of drought-responding EST-SSRs between upland and lowland rice in China.

    Directory of Open Access Journals (Sweden)

    Hui Xia

    Full Text Available Upland and lowland rice (Oryza sativa L. represent two of the most important rice ecotypes adapted to ago-ecosystems with contrasting soil-water conditions. Upland rice, domesticated in the water-limited environment, contains valuable drought-resistant characters that can be used in water-saving breeding. Knowledge about the divergence between upland and lowland rice will provide valuable cues for the evolution of drought-resistance in rice. Genetic differentiation between upland and lowland rice was explored by 47 Simple Sequence Repeats (SSRs located in drought responding expressed sequence tags (ESTs among 377 rice landraces. The morphological traits of drought-resistance were evaluated in the field experiments. Different outlier loci were detected in the japonica and indica subspecies, respectively. Considerable genetic differentiation between upland and lowland rice on these outlier loci was estimated in japonica (Fst = 0.258 and indica (Fst = 0.127. Furthermore, populations of the upland and lowland ecotypes were clustered separately on these outlier loci. A significant correlation between genetic distance matrices and the dissimilarity matrices of drought-resistant traits was determined, indicating a certain relationship between the upland-lowland rice differentiation and the drought-resistance. Divergent selections occur between upland and lowland rice on the drought-resistance as the Qsts of some drought-resistant traits are significantly higher than the neutral Fst. In addition, the upland- and lowland-preferable alleles responded differently among ecotypes or allelic types under osmotic stress. This shows the evolutionary signature of drought resistance at the gene expression level. The findings of this study can strengthen our understanding of the evolution of drought-resistance in rice with significant implications in the improvement of rice drought-resistance.

  20. EFFECT OF DROUGHT ON STRESS IN PLANTS

    Directory of Open Access Journals (Sweden)

    Jelena Marković

    2015-07-01

    Full Text Available Drought occurs due to lack of water in the soil, as well as due to disturbances in the circulation of the atmosphere. The duration of the drought may be different, and droughts not only the lack of rainfall, but also erratic distribution of rainfall throughout the year. The intensity of droughts amplified high temperatures, low relative humidity and dry, hot winds. The drought in many areas of common occurrence that repeats without a discernible regularity. Although it can be found in almost all parts of the world, its characteristics vary from region to region. Defining drought is therefore difficult and depends on regional differences and needs, but also from the perspective from which to observe this phenomenon. In the broadest sense, the drought is due to the lack of precipitation over an extended period of time, leading to water shortages for some activities, group activities or an entire sector of the environment. Drought can not be viewed solely as a physical phenomenon. The occurrence of drought, because of the weather, a lot of influences and reflects on the plants and agricultural production.

  1. Drought Monitoring for Rice Production in Cambodia

    Directory of Open Access Journals (Sweden)

    Nyda Chhinh

    2015-10-01

    Full Text Available Rice production underpins the national economy and the most rural livelihoods in Cambodia, but it is negatively impacted by repeated droughts. The research reported on in this paper focuses on relationships between drought occurrences in Cambodia’s most drought-prone province (Kampong Speu and (i damage to the annual rice harvest between 1994 and 2011, and (ii the Niño 3.4 index. Droughts were identified using the Standardised Precipitation Index (SPI. In seven of the years between 1994 and 2006 droughts damaged >1000 ha of rice in the Kampong Speu province. Furthermore, in 11 years >200 ha of rice were damaged. A critical success index of 0.66 obtained for an analysis of SPI-defined drought and area rice damage in the province indicates a strong statistical relationship. A statistically significant correlation (r = −0.455 was achieved between Niño 3.4 and 12-month SPI values lagged by three months, this indicates the importance of ENSO linkages in explaining drought in this region. Late season droughts lead to greater rice damage than early- and mid-season droughts.

  2. Differential display-mediated identification of three drought-responsive expressed sequence tags in tea [Camellia sinensis (L.) O. Kuntze

    Indian Academy of Sciences (India)

    Priti Sharma; Sanjay Kumar

    2005-03-01

    There is no information on drought-modulated gene(s) in tea [Camellia sinensis (L.) O. Kuntze], a woody and perennial plant of commercial importance. Using differential display of mRNA, three drought-modulated expressed sequence tags (ESTs) were identified. Northern and BLAST analysis revealed that clone dr1 (droughtresponsive), induced only by drought but not by ABA, showed significant scores with PR-5 (pathogenesis related) family of PR-protein gene. Another clone dr2, repressed by drought but not by ABA, had nucleotide repeats for polyasparate that are also present in chicken calsequestrin-like mRNA. Clone dr3, responded similarly to clone dr2 but did not show significant homology with the reported genes, hence appears to be novel. Identification of these ESTs is an initial step to clone the full length genes and their promoters.

  3. Development of a SMAP-Based Drought Monitoring Product

    Science.gov (United States)

    Sadri, S.; Wood, E. F.; Pan, M.; Lettenmaier, D. P.

    2016-12-01

    Agricultural drought is defined as a deficit in the amount of soil moisture over a prolonged period of time. Soil moisture information over time and space provides critical insight for agricultural management, including both water availability for crops and moisture conditions that affect management practices such as fertilizer, pesticide applications, and their impact as non-point pollution runoff. Since April of 2015, NASA's Soil Moisture Active Passive (SMAP) mission has retrieved soil moisture using L-band passive radiometric measurements at a 8 day repeat orbit with a swath of 1000 km that maps the Earth in 2-3 days depending on locations. Of particular interest to SMAP-based agricultural applications is a monitoring product that assesses the SMAP soil moisture in terms of probability percentiles for dry (drought) or wet (pluvial) conditions. SMAP observations do result in retrievals that are spatially and temporally discontinuous. Additionally, the short SMAP record length provides a statistical challenge in estimating a drought index and thus drought risk evaluations. In this presentation, we describe a SMAP drought index for the CONUS region based on near-surface soil moisture percentiles. Because the length of the SMAP data record is limited, we use a Bayesian conditional probability approach to extend the SMAP record back to 1979 based on simulated soil moisture of the same period from the Variable Infiltration Capacity (VIC) Land Surface Model (LSM), simulated by Princeton University. This is feasible because the VIC top soil layer (10 cm) is highly correlated with the SMAP 36 km passive microwave during 2015-2016, with more than half the CONUS grids having a cross-correlation greater than 0.6, and over 0.9 in many regions. Given the extended SMAP record, we construct an empirical probability distribution of near-surface soil moisture drought index showing severities similar to those used by the U.S. Drought Monitor (from D0-D4), for a specific SMAP

  4. Assessment of spatial and temporal drought in Iraq during the period 1980-2010

    Energy Technology Data Exchange (ETDEWEB)

    AL-Timimi, Yaseen K.; AL-Jiboori, Monim H. [Department of Atmospheric Sciences, College of Science, AL-Mustansiriyah University, Baghdad (Iraq)

    2013-07-01

    This study investigated the frequency of drought for the period 1980 to 2010 in Iraq, based on monthly rainfall data were collected from 39 meteorological stations distributed across the country and digitally encoded into a GIS database. The standardized precipitation index (SPI) is used to evaluated the spatial and temporal characteristics of meteorological drought. The result of SPI analysis reveal that the country faced during the past 30 years frequent non-uniform drought periods in an irregular repetitive manner. the paper suggest the presence of two drought types, local drought and national drought, Drought severity Classes; near normal drought, moderate drought, severe drought and extreme drought increased with time from normal to extreme levels especially at last decade. The result show the year 2008 was the worst dry year during the period, 30% of the area is under extreme drought, 36% under severe drought, 22% of the area is under moderate drought and 12% is near normal.

  5. Assessment of spatial and temporal drought in Iraq during the period 1980-2010

    Directory of Open Access Journals (Sweden)

    Yaseen K. AL-Timimi, Monim H. AL-Jiboori

    2013-01-01

    Full Text Available This study investigated the frequency of drought for the period 1980 to 2010 in Iraq, based on monthly rainfall data were collected from 39 meteorological stations distributed across the country and digitally encoded into a GIS database. The standardized precipitation index (SPI is used to evaluated the spatial and temporal characteristics of meteorological drought. The result of SPI analysis reveal that the country faced during the past 30 years frequent non-uniform drought periods in an irregular repetitive manner. the paper suggest the presence of two drought types, local drought and national drought, Drought severity Classes; near normal drought, moderate drought, severe drought and extreme drought increased with time from normal to extreme levels especially at last decade. The result show the year 2008 was the worst dry year during the period, 30% of the area is under extreme drought, 36% under severe drought, 22% of the area is under moderate drought and 12% is near normal.

  6. Seasonal Drought Prediction in India

    Science.gov (United States)

    Shah, R.; Mishra, V.

    2015-12-01

    Drought is among the most costly natural disasters in India. Seasonal prediction of drought can assist planners to manage agriculture and water resources. Such information can be valuable for a country like India where 60% of agriculture is rain-fed. Here we evaluate precipitation and temperature forecast from the NCEP's CFSV2 for seasonal drought prediction in India. We demonstrate the utility of the seasonal prediction of precipitation and temperature for drought forecast at 1-2 months lead time at a high spatial resolution. Precipitation from CFSv2 showed moderate correlations with observed up to two months lead. For one month lead, we found a significant correlation between CFSv2 and observed precipitation during winter season. Air temperature from the CFSv2 showed a good correlation with observed temperature during the winter. We forced the Variable Infiltration Capacity (VIC) model with the CFSv2 forecast of precipitation and air temperature to generate forecast of hydrologic variables such as soil moisture and total runoff. We find that errors of the prediction reduce for the two month lead time in the majority of the study domain except the northern India. Skills of Initial Hydrologic Conditions combined with moderate skills of forcings based on the CFSv2 showed ability of drought prediction in India. The developed system was able to successfully predict observed top layer soil moisture and observed drought based on satellite remote sensing in India.

  7. Fighting Against Drought

    Institute of Scientific and Technical Information of China (English)

    YIN PUMIN

    2010-01-01

    @@ The severe drought in southwest China continues and has worsened shortages of drinking water,as recent rainfall in these areas has been far from adequate,said China's drought relief authorities on April 8. The drought situation is looking quite grave,said Chen Lei,Deputy Director of the Office of State Flood Control and Drought Relief Headquarters(SFDH).

  8. Assessment of remotely sensed drought features in vulnerable agriculture

    Directory of Open Access Journals (Sweden)

    N. R. Dalezios

    2012-10-01

    Full Text Available The growing number and effectiveness of Earth observation satellite systems, along with the increasing reliability of remote sensing methodologies and techniques, present a wide range of new capabilities in monitoring and assessing droughts. A number of drought indices have been developed based on NOAA-AVHRR data exploiting the remote sensing potential at different temporal scales. In this paper, the remotely sensed Reconnaissance Drought Index (RDI is employed for the quantification of drought. RDI enables the assessment of hydro-meteorological drought, since it uses hydrometeorological parameters, such as precipitation and potential evapotranspiration. The study area is Thessaly, central Greece, which is a drought-prone agricultural region characterized by vulnerable agriculture. Several drought features are analyzed and assessed by using monthly RDI images over the period 1981–2001: severity, areal extent, duration, periodicity, onset and end time. The results show an increase in the areal extent during each drought episode and that droughts are classified into two classes, namely small areal extent drought and large areal extent drought, respectively, lasting 12 or 13 months coinciding closely with the hydrological year. The onset of large droughts coincides with the beginning of the hydrological year, whereas the onset of small droughts is in spring. During each drought episode, the maximum occurs usually in the summer and they all last until the end of the hydrological year. This finding could justify an empirical prognostic potential of drought assessment.

  9. Spatiotemporal Characteristics of Groundwater Drought and Its Response to Meteorological Drought in Jiangsu Province, China

    Directory of Open Access Journals (Sweden)

    Bo Liu

    2016-10-01

    Full Text Available In this study, the temporal and spatial variations of groundwater drought using a Standardized Groundwater Level Index (SGI were analyzed based on 40 monthly groundwater level observation wells from 1989 to 2012 in Jiangsu Province, China. Meteorological drought, calculated by the Standardized Precipitation Index (SPI, was also included to reveal its propagation and impact on the groundwater drought process. Results showed that the southern region of Jiangsu faced more frequent groundwater droughts and lower intensity, while the northern region faced less frequent groundwater drought with higher intensity. Furthermore, the cross-correlation between the spatial average of SGI and SPI for SPI accumulation periods of q = 1 to 12 was computed. The relationship between SGI and SPI varied in different regions. Detailed analysis of the characteristics of groundwater and meteorological drought for each region showed that meteorological droughts happened more frequently than groundwater drought in Jiangsu Province during the study period, while the mean duration and mean magnitude of groundwater droughts were longer and larger than those of meteorological droughts. It is expected that this study will provide useful information for drought monitoring and mitigation in Jiangsu and similar areas.

  10. Impacts of Climate Change on Droughts in Gilan Province, Iran

    Directory of Open Access Journals (Sweden)

    Ladan Kazemi Rad

    2015-06-01

    Full Text Available Drought as a complex natural hazard is best characterized by multiple climatological and hydrological parameters and its assessment is important for planning and managing water resources. So understanding the history of drought in an area is essential like investigating the effects of drought. In this study at first climate parameters affecting the drought have downscaled by LARS-WG stochastic weather generator over Gilan province in Iran. After choosing a suitable model, the outputs were used for assessing the drought situation in the period of 2011-2030. Assessing the drought was done by TOPSIS method during 2 periods (present and future. After validation of the method, zoning the drought was performed by IDW method in GIS. Results showed that the expanse of situations with lower drought index will increase. Also we will expect more droughts in these regions for the future.

  11. Drought in West Africa

    Science.gov (United States)

    2007-01-01

    Drought settled over West Africa's Ivory Coast region when wet season rains came late in 2007. Instead of beginning in February, the rainy season didn't start until March, and steady rains didn't start until late March, said the Famine Early Warning System Network. Though the rain had started to alleviate the drought, vegetation was still depressed in parts of Cote d'Ivoire (Ivory Coast) between March 22 and April 6, 2007, when the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite captured the data used to make this image. The image shows current vegetation conditions compared to average conditions recorded since 2000. Areas where plants are growing more slowly or more sparsely than average are brown, while areas where vegetation is denser than average are green. The brown tint that dominates the image indicates that plants through most of the country are more sparse than normal. Among the crops affected by the lack of rain was West Africa's cocoa crop. About 70 percent of the world's cocoa comes from West Africa, and Cote d'Ivoire is a top grower, said Reuters. Cocoa prices climbed as the crop fell short. Farmers called the drought the worst in living memory, Reuters said. The delay in rainfall also led to water shortages in parts of Cote d'Ivoire, according to the United Nations Office for the Coordination of Humanitarian Affairs.

  12. A baseline probabilistic drought forecasting framework using Standardized Soil Moisture Index: application to the 2012 United States drought

    Directory of Open Access Journals (Sweden)

    A. AghaKouchak

    2014-02-01

    Full Text Available The 2012 drought was one of the most extensive drought events in half a century, resulting in billions of US dollars in economic loss in the US, and substantial indirect impacts on global food security and commodity prices. An important feature of the 2012 drought was rapid development and intensification in late spring/early summer, a critical time for crop development and investment planning. Drought prediction remains a major challenge because dynamical precipitation forecasts are highly uncertain, and their prediction skill is low. Using a probabilistic framework for drought forecasting based on the persistence property of accumulated soil moisture, this paper shows that the US drought of summer 2012 was predictable several months in advance. The presented drought forecasting framework provides the probability occurrence of drought based on climatology and near-past observations of soil moisture. Our results indicate that soil moisture exhibits higher persistence than precipitation, and hence improves drought predictability.

  13. Drought-mortality relationships for tropical forests.

    Science.gov (United States)

    Phillips, Oliver L; van der Heijden, Geertje; Lewis, Simon L; López-González, Gabriela; Aragão, Luiz E O C; Lloyd, Jon; Malhi, Yadvinder; Monteagudo, Abel; Almeida, Samuel; Dávila, Esteban Alvarez; Amaral, Iêda; Andelman, Sandy; Andrade, Ana; Arroyo, Luzmila; Aymard, Gerardo; Baker, Tim R; Blanc, Lilian; Bonal, Damien; de Oliveira, Atila Cristina Alves; Chao, Kuo-Jung; Cardozo, Nallaret Dávila; da Costa, Lola; Feldpausch, Ted R; Fisher, Joshua B; Fyllas, Nikolaos M; Freitas, Maria Aparecida; Galbraith, David; Gloor, Emanuel; Higuchi, Niro; Honorio, Eurídice; Jiménez, Eliana; Keeling, Helen; Killeen, Tim J; Lovett, Jon C; Meir, Patrick; Mendoza, Casimiro; Morel, Alexandra; Vargas, Percy Núñez; Patiño, Sandra; Peh, Kelvin S-H; Cruz, Antonio Peña; Prieto, Adriana; Quesada, Carlos A; Ramírez, Fredy; Ramírez, Hirma; Rudas, Agustín; Salamão, Rafael; Schwarz, Michael; Silva, Javier; Silveira, Marcos; Slik, J W Ferry; Sonké, Bonaventure; Thomas, Anne Sota; Stropp, Juliana; Taplin, James R D; Vásquez, Rodolfo; Vilanova, Emilio

    2010-08-01

    *The rich ecology of tropical forests is intimately tied to their moisture status. Multi-site syntheses can provide a macro-scale view of these linkages and their susceptibility to changing climates. Here, we report pan-tropical and regional-scale analyses of tree vulnerability to drought. *We assembled available data on tropical forest tree stem mortality before, during, and after recent drought events, from 119 monitoring plots in 10 countries concentrated in Amazonia and Borneo. *In most sites, larger trees are disproportionately at risk. At least within Amazonia, low wood density trees are also at greater risk of drought-associated mortality, independent of size. For comparable drought intensities, trees in Borneo are more vulnerable than trees in the Amazon. There is some evidence for lagged impacts of drought, with mortality rates remaining elevated 2 yr after the meteorological event is over. *These findings indicate that repeated droughts would shift the functional composition of tropical forests toward smaller, denser-wooded trees. At very high drought intensities, the linear relationship between tree mortality and moisture stress apparently breaks down, suggesting the existence of moisture stress thresholds beyond which some tropical forests would suffer catastrophic tree mortality.

  14. Probabilistic assessment of agricultural droughts using graphical models

    Science.gov (United States)

    Ramadas, Meenu; Govindaraju, Rao S.

    2015-07-01

    Agricultural droughts are often characterized by soil moisture in the root zone of the soil, but crop needs are rarely factored into the analysis. Since water needs vary with crops, agricultural drought incidences in a region can be characterized better if crop responses to soil water deficits are also accounted for in the drought index. This study investigates agricultural droughts driven by plant stress due to soil moisture deficits using crop stress functions available in the literature. Crop water stress is assumed to begin at the soil moisture level corresponding to incipient stomatal closure, and reaches its maximum at the crop's wilting point. Using available location-specific crop acreage data, a weighted crop water stress function is computed. A new probabilistic agricultural drought index is then developed within a hidden Markov model (HMM) framework that provides model uncertainty in drought classification and accounts for time dependence between drought states. The proposed index allows probabilistic classification of the drought states and takes due cognizance of the stress experienced by the crop due to soil moisture deficit. The capabilities of HMM model formulations for assessing agricultural droughts are compared to those of current drought indices such as standardized precipitation evapotranspiration index (SPEI) and self-calibrating Palmer drought severity index (SC-PDSI). The HMM model identified critical drought events and several drought occurrences that are not detected by either SPEI or SC-PDSI, and shows promise as a tool for agricultural drought studies.

  15. Occurrences and Effects of Drought across Africa

    Science.gov (United States)

    Mwangi, M. N.

    2009-12-01

    Drought is a common occurrence in Africa and its effects vary temporally and spatially across the continent. The objective of this paper is to synthesize available information on droughts in Africa in order to discern emerging trends vis-à-vis spatiotemporal occurrences, impacts and adaptation. Drought forcings in the Sahelian region and southern Africa are predominately related to the passage of mid-latitude air masses while in locations near the equator is strongly linked to the position of ITCZ, except perhaps in the deserts where albedo may predominate. The review shows that drought occurrences have increased both temporally and spatially; its effects on the society vary across scales, and are influenced by political, economic, social, cultural, and ecological factors. The drought occurrence and its impacts varied spatially and temporally. The effect of drought also varied with socioeconomic sector; agriculture and pastoralism were the widely reported. The greater horn of Africa, specifically Kenya, has the most continuous record of droughts. The synthesis also reveals that a suite of drought adaptation strategies exists at the local scale; in contrasts, at the aggregate scale, coping strategies are scarce. Drought management tailored for specific livelihood system or societies are non-existent. The study found that occurrence of drought alongside issues related to the multiscale political economy affect the viability of most adaptation strategies used by societies across Africa. Drought management has been silent on the social, political, and economic dimensions that reasonably aggravate the vulnerability of lives and livelihood systems to this climatic hazard. The effect of drought and social pressures is relational and simultaneous to such a degree that differential vulnerability among communities across Africa is to be expected. Although scenarios about rainfall and drought vis-à-vis Africa are largely contested there is a general indication that most

  16. Developing a European Drought Observatory for Monitoring, Assessing and Forecasting Droughts across the European Continent

    Science.gov (United States)

    Vogt, J.; Barbosa, P.; Hofer, B.; Magni, D.; Jager, A. D.; Singleton, A.; Horion, S.; Sepulcre, G.; Micale, F.; Sokolova, E.; Calcagni, L.; Marioni, M.; Antofie, T. E.

    2011-12-01

    Many European countries have repeatedly been affected by droughts, resulting in considerable ecological and economic damage. Climate change studies indicate a trend towards increasing climate variability most likely resulting in more frequent drought occurrences also in Europe. Against this background, the European Commission's Joint Research Centre (JRC) is developing methods and tools for assessing, monitoring and forecasting droughts in Europe and develops a European Drought Observatory (EDO) to complement national activities with a European view. As droughts affect the entire water cycle continuous monitoring of a suite of indicators is required. Drought indicators at continental scale are supplemented by indicators at national, regional and local scales, providing more detailed information. At the core of the European Drought Observatory (EDO) are a portal and a map server presenting Europe-wide up-to-date drought-relevant information to the public and to decision makers in policy and water resources management. The final portal will include access to metadata catalogues, media reports, a map server and other related resources. The current version of EDO publishes continental information based on data processed and analysed at JRC as well as more detailed information at national and river basin scale processed by the local authorities. Available drought products include monthly updated Standardized Precipitation Indices (SPI), modelled soil moisture anomalies, remote sensing observations on the state of the vegetation cover (i.e. fAPAR and NDWI) and groundwater levels. A one-week soil moisture anomaly forecast complements the picture. Access to information at the national and river basin scale is established through interoperability arrangements with local authorities, making use of a special metadata catalogue and OWS standards (especially WMS and WCS). In addition, time series of drought indices can be retrieved for grid cells and administrative regions in

  17. Drought and Snow: Analysis of Drivers, Processes and Impacts of Streamflow Droughts in Snow-Dominated Regions

    Science.gov (United States)

    Van Loon, Anne; Laaha, Gregor; Van Lanen, Henny; Parajka, Juraj; Fleig, Anne; Ploum, Stefan

    2016-04-01

    Around the world, drought events with severe socio-economic impacts seem to have a link with winter snowpack. That is the case for the current California drought, but analysing historical archives and drought impact databases for the US and Europe we found many impacts that can be attributed to snowpack anomalies. Agriculture and electricity production (hydropower) were found to be the sectors that are most affected by drought related to snow. In this study, we investigated the processes underlying hydrological drought in snow-dominated regions. We found that drought drivers are different in different regions. In Norway, more than 90% of spring streamflow droughts were preceded by below-average winter precipitation, while both winter air temperature and spring weather were indifferent. In Austria, however, spring streamflow droughts could only be explained by a combination of factors. For most events, winter and spring air temperatures were above average (70% and 65% of events, respectively), and winter and spring precipitation was below average (75% and 80%). Because snow storage results from complex interactions between precipitation and temperature and these variables vary strongly with altitude, snow-related drought drivers have a large spatial variability. The weather input is subsequently modified by land properties. Multiple linear regression between drought severity variables and a large number of catchment characteristics for 44 catchments in Austria showed that storage influences both drought duration and deficit volume. The seasonal storage of water in snow and glaciers was found to be a statistically important variable explaining streamflow drought deficit. Our drought impact analysis in Europe also showed that 40% of the selected drought impacts was caused by a combination of snow-related and other drought types. For example, the combination of a winter drought with a preceding or subsequent summer drought was reported to have a large effect on

  18. Linkage disequilibrium and association mapping of drought ...

    African Journals Online (AJOL)

    sunny t

    2016-11-16

    Nov 16, 2016 ... deficit for agricultural production, development of drought tolerant crop to ... it has a long history of improvement through conventional breeding ... 19.2% of the phenotypic variation (PV). Rodriguez- ... phenotypic trait (Saeed et al., 2014). Genome- ..... repeat; TASSEL, trait analysis by association, evolution.

  19. Variation of drought over northern China during 1950-2000

    Institute of Scientific and Technical Information of China (English)

    WANGZhiwei; ZHAIPanmao; ZHANGHongtao

    2003-01-01

    Based on China's monthly precipitation data of 629 stations during 1950-2000, we calculated Z indices and separated them into seven Dryness and Wemess grades. Further, a drought area index was proposed to study changes in drought severity in northern China. The results revealed that the different severity of droughts all showed expanding trends in northern China's main agricultural area. Moreover, the area coverage of droughts in different seasons and different regions disolaved different trends.

  20. Bacteria associated with highly drought resistant Pistacia terebinthus: the key to reduce drought stress in other plant species?

    OpenAIRE

    Van de Weyer, Inge

    2013-01-01

    Plant-associated bacteria can not only stimulate plant growth, but also play an important role in the adaptation of their host plant to stress-inducing environmental conditions such as extreme drought. In this project, the effect of inoculation with selected endophytic bacteria isolated from the highly drought resistant tree Pistacia terebinthus on the drought resistance of four different plant species was evaluated. The results show that drought had a strong negative impact on all plant spec...

  1. Index System and Influence of Drought in Northwest China

    Institute of Scientific and Technical Information of China (English)

    Liu Yinge; Wen Yanjun

    2008-01-01

    In this paper, the index systems of the agricultural drought and decrease percentage of grain crop are established. The trend and influence of drought in the region is analyzed based on the 50 years (1951-2000) statistical data of precipitation and 52 years (1951-2002) agricultural drought of the region, including five provinces: Shaanxi, Gansu, Ningxia, Qinghai and Xinjiang. The result shows that the drought disaster is increasing and the most serious were in the 1970s and 1990s, and main agricultural drought is a great disaster incident. The regression prediction equation of drought and flood grades and agricultural drought areas grades are set up by the harmonic wave method, and forecasting the drought will lighten during the first ten years of the 21st century.

  2. Managing Water Resources for Drought: Insights from California

    Science.gov (United States)

    Medellin-Azuara, Josue; Lund, Jay

    2016-04-01

    Droughts bring great opportunities to better understand and improve water systems. California's economic powerhouse relies on highly engineered water systems to fulfill large and growing urban and agricultural water demands. Current and past droughts show these systems are highly robust and resilient to droughts, as they recover promptly. However, environmental systems remain highly vulnerable and have shown less resilience to drought, with each drought bringing additional native species closer to extinction, often with little recovery following the drought. This paper provides an overview of the economic and ecosystem impacts of the recent multi-year drought in California in the context of a global economy. We explore the potential of water markets, groundwater management and use of remote sensing technology to improve understanding of adaptation to drought. Insights for future management of water resources and scientific work are discussed.

  3. Generalized drought assessment in Dongliao river basin based on water resources system

    Science.gov (United States)

    Weng, B. S.; Yan, D. H.; Wang, H.; Qin, T. L.; Yin, J.

    2014-11-01

    Drought is firstly a resource issue, and with its development it transforms into a disaster issue. The occurrences of drought events usually feature determinacy and randomness. Drought issue has become one of the major factors to affect sustainable economic and social development. In this paper, we propose the generalized drought assessment index (GDAI) based on water resources system for assessing drought events. The GDAI considers water supply and water demand using a distributed hydrological model. We demonstrate the use of the proposed index in the Dongliao river basin (DRB) in the northeast China. The results simulated by the GDAI are then compared to observed drought disaster records in DRB. As second, the temporal distribution of drought events and the spatial distribution of drought frequency from the GDAI are compared with the traditional approach (i.e. the SPI, the PDSI, and the RWD). Then, generalized drought times (GDT), generalized drought duration (GDD), and generalized drought severity (GDS) were calculated by theory of runs. Application of the GDT, the GDD, and the GDS of various drought levels (i.e. mild drought, moderate drought, severe drought, and extreme drought) to the period 1960-2010 shows that the centers of gravity of them are all distributed in the middle reached of DRB, and change with time. The proposed methodology helps water managers in water-stressed regions to quantify the impact of drought, consequently, to make decisions regarding coping with drought issue.

  4. Generalized drought assessment in Dongliao river basin based on water resources system

    Directory of Open Access Journals (Sweden)

    B. S. Weng

    2014-11-01

    Full Text Available Drought is firstly a resource issue, and with its development it transforms into a disaster issue. The occurrences of drought events usually feature determinacy and randomness. Drought issue has become one of the major factors to affect sustainable economic and social development. In this paper, we propose the generalized drought assessment index (GDAI based on water resources system for assessing drought events. The GDAI considers water supply and water demand using a distributed hydrological model. We demonstrate the use of the proposed index in the Dongliao river basin (DRB in the northeast China. The results simulated by the GDAI are then compared to observed drought disaster records in DRB. As second, the temporal distribution of drought events and the spatial distribution of drought frequency from the GDAI are compared with the traditional approach (i.e. the SPI, the PDSI, and the RWD. Then, generalized drought times (GDT, generalized drought duration (GDD, and generalized drought severity (GDS were calculated by theory of runs. Application of the GDT, the GDD, and the GDS of various drought levels (i.e. mild drought, moderate drought, severe drought, and extreme drought to the period 1960–2010 shows that the centers of gravity of them are all distributed in the middle reached of DRB, and change with time. The proposed methodology helps water managers in water-stressed regions to quantify the impact of drought, consequently, to make decisions regarding coping with drought issue.

  5. How useful are meteorological drought indicators to assess agricultural drought impacts across Europe?

    Science.gov (United States)

    Bachmair, Sophie; Tanguy, Maliko; Hannaford, Jamie; Stahl, Kerstin

    2016-04-01

    between meteorological drought indicators and remotely sensed vegetation stress at the EU NUTS3 region level revealed a high correlation between the two types of indicators for many regions; however some spatial variability was observed in (i) strength of correlation, (ii) performance of SPI versus SPEI, and (iii) best linked SPI/SPEI time scale. We additionally explored whether geographic properties like climate, soil texture, land use, and location explain the observed spatial patterns. Our study revealed that climatically dryer areas (water limited) showed high correlations between SPI/SPEI and vegetation stress, whereas the wettest parts of Europe (radiation limited regions) showed negative correlations especially for short accumulation periods, suggesting that for these regions, short droughts could actually be beneficial for vegetation growth. These findings suggest that relying solely on meteorological indicators for agricultural risk assessment in some regions might be inadequate. Overall, such information may help to tailor agricultural drought M&EW systems to specific regions.

  6. The European Drought Observatory (EDO): Current State and Future Directions

    Science.gov (United States)

    Vogt, Jürgen; Sepulcre, Guadalupe; Magni, Diego; Valentini, Luana; Singleton, Andrew; Micale, Fabio; Barbosa, Paulo

    2013-04-01

    Europe has repeatedly been affected by droughts, resulting in considerable ecological and economic damage and climate change studies indicate a trend towards increasing climate variability most likely resulting in more frequent drought occurrences also in Europe. Against this background, the European Commission's Joint Research Centre (JRC) is developing methods and tools for assessing, monitoring and forecasting droughts in Europe and develops a European Drought Observatory (EDO) to complement and integrate national activities with a European view. At the core of the European Drought Observatory (EDO) is a portal, including a map server, a metadata catalogue, a media-monitor and analysis tools. The map server presents Europe-wide up-to-date information on the occurrence and severity of droughts, which is complemented by more detailed information provided by regional, national and local observatories through OGC compliant web mapping and web coverage services. In addition, time series of historical maps as well as graphs of the temporal evolution of drought indices for individual grid cells and administrative regions in Europe can be retrieved and analysed. Current work is focusing on validating the available products, developing combined indicators, improving the functionalities, extending the linkage to additional national and regional drought information systems and testing options for medium-range probabilistic drought forecasting across Europe. Longer-term goals include the development of long-range drought forecasting products, the analysis of drought hazard and risk, the monitoring of drought impact and the integration of EDO in a global drought information system. The talk will provide an overview on the development and state of EDO, the different products, and the ways to include a wide range of stakeholders (i.e. European, national river basin, and local authorities) in the development of the system as well as an outlook on the future developments.

  7. What causes southeast Australia's worst droughts?

    Science.gov (United States)

    Ummenhofer, Caroline C.; England, Matthew H.; McIntosh, Peter C.; Meyers, Gary A.; Pook, Michael J.; Risbey, James S.; Gupta, Alexander Sen; Taschetto, Andréa S.

    2009-02-01

    Since 1995, a large region of Australia has been gripped by the most severe drought in living memory, the so-called ``Big Dry''. The ramifications for affected regions are dire, with acute water shortages for rural and metropolitan areas, record agricultural losses, the drying-out of two of Australia's major river systems and far-reaching ecosystem damage. Yet the drought's origins have remained elusive. For Southeast Australia, we show here that the ``Big Dry'' and other iconic 20th Century droughts, including the Federation Drought (1895-1902) and World War II drought (1937-1945), are driven by Indian Ocean variability, not Pacific Ocean conditions as traditionally assumed. Specifically, a conspicuous absence of Indian Ocean temperature conditions conducive to enhanced tropical moisture transport has deprived southeastern Australia of its normal rainfall quota. In the case of the ``Big Dry'', its unprecedented intensity is also related to recent higher temperatures.

  8. Early osmotic adjustment responses in drought-resistant and drought-sensitive oilseed rape

    Institute of Scientific and Technical Information of China (English)

    Sarah Hatzig; L Irina Zaharia; Suzanne Abrams; Marie Hohmann; Laurie Legoahec; Alain Bouchereau; Nathalie Nesi; Rod J.Snowdon

    2014-01-01

    The impact of osmotic stress on growth, physiolo-gy, and metabolism of winter oilseed rape (Brassica napus L.) was investigated by detailed analysis of biomass traits, hormone metabolites and osmolytes in two genetical y unrelated drought-tolerant genotypes and two unrelated drought-sensitive genotypes. Seedlings were grown in vitro under control ed conditions and osmotic stress was simulated by applying a gradual treatment with polyethylene glycol (PEG 6000), fol owed by hypo-osmotic treatment of variants used for metabolite determination. The results provide a basis for the identification of reliable selection criteria for drought resistance in oilseed rape. The in vitro cultivation system established during this study enabled effective discrimination of early osmotic stress responses between drought-resistant and-susceptible oilseed rape genotypes that also show large differences in relative seed yield under drought conditions in the field. Clear physiological and metabolic differences were observed between the drought-resistant and drought-sensitive genotypes, suggesting that osmotic adjustment is a key component of drought response in oilseed rape. Unexpected-ly, however, the drought-resistant genotypes did not show typical hormonal adjustment and osmolyte accumulation, suggesting that they possess alternative physiological mech-anisms enabling avoidance of stress symptoms.

  9. Improved tolerance to post-anthesis drought stress by pre-drought priming at vegetative stages in drought-tolerant and -sensitive wheat cultivars.

    Science.gov (United States)

    Abid, Muhammad; Tian, Zhongwei; Ata-Ul-Karim, Syed Tahir; Liu, Yang; Cui, Yakun; Zahoor, Rizwan; Jiang, Dong; Dai, Tingbo

    2016-09-01

    Wheat crop endures a considerable penalty of yield reduction to escape the drought events during post-anthesis period. Drought priming under a pre-drought stress can enhance the crop potential to tolerate the subsequent drought stress by triggering a faster and stronger defense mechanism. Towards these understandings, a set of controlled moderate drought stress at 55-60% field capacity (FC) was developed to prime the plants of two wheat cultivars namely Luhan-7 (drought tolerant) and Yangmai-16 (drought sensitive) during tillering (Feekes 2 stage) and jointing (Feekes 6 stage), respectively. The comparative response of primed and non-primed plants, cultivars and priming stages was evaluated by applying a subsequent severe drought stress at 7 days after anthesis. The results showed that primed plants of both cultivars showed higher potential to tolerate the post-anthesis drought stress through improved leaf water potential, more chlorophyll, and ribulose-1, 5-bisphosphate carboxylase/oxygenase contents, enhanced photosynthesis, better photoprotection and efficient enzymatic antioxidant system leading to less yield reductions. The primed plants of Luhan-7 showed higher capability to adapt the drought stress events than Yangmai-16. The positive effects of drought priming to sustain higher grain yield were pronounced in plants primed at tillering than those primed at jointing. In consequence, upregulated functioning of photosynthetic apparatus and efficient enzymatic antioxidant activities in primed plants indicated their superior potential to alleviate a subsequently occurring drought stress, which contributed to lower yield reductions than non-primed plants. However, genotypic and priming stages differences in response to drought stress also contributed to affect the capability of primed plants to tolerate the post-anthesis drought stress conditions in wheat.

  10. Changes of RWC, Wilting Degree and ABA in Different Ramie Varieties under Drought Stress

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Changes of RWC, wilting degree and ABA in different ramie varieties under drought stress were studied. The results showed: (1) wilting degree and ABA increased but RWC decreased with the increase of drought sress,and (2) drought resistant varieties had higher RWC and ABA but lower wilting degree than drought sensitive varieties.

  11. A comprehensive drought monitoring method integrating MODIS and TRMM data

    Science.gov (United States)

    Du, Lingtong; Tian, Qingjiu; Yu, Tao; Meng, Qingyan; Jancso, Tamas; Udvardy, Peter; Huang, Yan

    2013-08-01

    Drought is a complex hazard caused by the breaking of water balance and it has always an impact on agricultural, ecological and socio-economic spheres. Although the drought indices deriving from remote sensing data have been used to monitor meteorological or agricultural drought, there are no indices that can suitably reflect the comprehensive information of drought from meteorological to agricultural aspects. In this paper, the synthesized drought index (SDI) is defined as a principal component of vegetation condition index (VCI), temperature condition index (TCI) and precipitation condition index (PCI). SDI integrates multi-source remote sensing data from moderate resolution imaging spectroradiometer (MODIS) and tropical rainfall measuring mission (TRMM) and it synthesizes precipitation deficits, soil thermal stress and vegetation growth status in drought process. Therefore, this method is favorable to monitor the comprehensive drought. In our research, a heavy drought process was accurately explored using SDI in Shandong province, China from 2010 to 2011. Finally, a validation was implemented and its results show that SDI is not only strongly correlated with 3-month scales standardized precipitation index (SPI3), but also with variation of crop yield and drought-affected crop areas. It was proved that this index is a comprehensive drought monitoring indicator and it can contain not only the meteorological drought information but also it can reflect the drought influence on agriculture.

  12. Droughts in the Czech Lands: Past, Present and Future

    Science.gov (United States)

    Brázdil, Rudolf; Trnka, Miroslav

    2015-04-01

    The presentation highlights main results of the InterDrought project (2013-2015), which includes several Czech universities and research institutes, and also shows overview of multidisciplinary scientific monograph on drought. The basic data sources consisting of instrumental, documentary, tree-ring and satellite data are presented. Selected drought indices (SPI, SPEI, Z-index and PDSI) calculated from homogenised Czech temperature and precipitation series are used to describe spatial and temporal variability of droughts in the Czech Lands for the 1804-2010 period including selection of drought extreme episodes and their detail description with respect to meteorological and synoptic patterns and impacts as well. Analysis of droughts prior 1804 is based on documentary data and oak tree-ring widths used for compilation of 500-year Czech drought chronology. The occurrence of extreme droughts is further analysed with respect to sea-level pressure patterns in the Atlantic-European area, climate forcings and changes in land-use. Examples of agricultural and hydrological droughts are mentioned. High resolution soil moisture models are used to estimate drought trends in last five decades as well as estimate future development of droughts in the Czech Republic. Overview represented by this paper will be complemented by several individual detail studies of other InterDrought Team members.

  13. Study on Diversity of Soybean Germplasm with Drought Resistance in Huang-Huai-Hai Region

    Institute of Scientific and Technical Information of China (English)

    LU Gui-he; LIU Xue-yi; REN Xiao-jun; SHI Hong

    2002-01-01

    Fifty soybean germplasms with drought resistance selected from Huang-Huai-Hai Region were studied under field drought condition. The results showed that there was a diversity of drought resistance at different growth stages. Some varieties had drought resistance in whole growing period, but some only at one stage or several stages. Some varieties had both drought resistance and higher yield characters, some with drought resistance but lower yield. It was also found in present study that some drought resistant germplasms showed higher yield potentials under irrigation condition.

  14. Quantum repeated games revisited

    CERN Document Server

    Frackiewicz, Piotr

    2011-01-01

    We present a scheme for playing quantum repeated 2x2 games based on the Marinatto and Weber's approach to quantum games. As a potential application, we study twice repeated Prisoner's Dilemma game. We show that results not available in classical game can be obtained when the game is played in the quantum way. Before we present our idea, we comment on the previous scheme of playing quantum repeated games.

  15. Drought assessment using a multivariate drought index in the Huaihe River basin of Eastern China

    Science.gov (United States)

    Li, Q.; Zeng, M.; Wang, H.; Li, P.; Wang, K.; Yu, M.

    2015-06-01

    The Huaihe River Basin having China's highest population density (662 persons per km2) lies in a transition zone between the climates of North and South China, and is thus prone to drought. Therefore, the paper aims to develop an appropriate drought assessment approach for drought assessment in the Huaihe River basin, China. Based on the Principal Component Analysis of precipitation, evapotranspiration, soil moisture and runoff, the three latter variables of which were obtained by use of the Xin'anjiang model, a new multivariate drought index (MDI) was formulated, and its thresholds were determined by use of cumulative distribution function. The MDI, the Standardized Precipitation Index (SPI) and the self-calibrating Palmer Drought Severity Index (sc-PDSI) time series on a monthly scale were computed and compared during 1988, 1999/2000 and 2001 drought events. The results show that the MDI exhibited certain advantages over the sc-PDSI and the SPI in monitoring drought evolution. The MDI formulated by this paper could provide a scientific basis for drought mitigation and management, and references for drought assessment elsewhere in China.

  16. Drought in the southeast

    Science.gov (United States)

    Stacy Clark; Martin Spetich; Zander Evans

    2008-01-01

    A historic drought gripped the Southeast region in 2007. It was the second driest year on record for the region, and rainfall in some areas including Alabama and North Carolina was the lowest on record for the last century. By the end of 2007, over a third of the region was classified in "exceptional" drought (the worst drought designation used by the U.S....

  17. A general framework for multivariate multi-index drought prediction based on Multivariate Ensemble Streamflow Prediction (MESP)

    Science.gov (United States)

    Hao, Zengchao; Hao, Fanghua; Singh, Vijay P.

    2016-08-01

    Drought is among the costliest natural hazards worldwide and extreme drought events in recent years have caused huge losses to various sectors. Drought prediction is therefore critically important for providing early warning information to aid decision making to cope with drought. Due to the complicated nature of drought, it has been recognized that the univariate drought indicator may not be sufficient for drought characterization and hence multivariate drought indices have been developed for drought monitoring. Alongside the substantial effort in drought monitoring with multivariate drought indices, it is of equal importance to develop a drought prediction method with multivariate drought indices to integrate drought information from various sources. This study proposes a general framework for multivariate multi-index drought prediction that is capable of integrating complementary prediction skills from multiple drought indices. The Multivariate Ensemble Streamflow Prediction (MESP) is employed to sample from historical records for obtaining statistical prediction of multiple variables, which is then used as inputs to achieve multivariate prediction. The framework is illustrated with a linearly combined drought index (LDI), which is a commonly used multivariate drought index, based on climate division data in California and New York in the United States with different seasonality of precipitation. The predictive skill of LDI (represented with persistence) is assessed by comparison with the univariate drought index and results show that the LDI prediction skill is less affected by seasonality than the meteorological drought prediction based on SPI. Prediction results from the case study show that the proposed multivariate drought prediction outperforms the persistence prediction, implying a satisfactory performance of multivariate drought prediction. The proposed method would be useful for drought prediction to integrate drought information from various sources

  18. Mapping Regional Drought Vulnerability: a Case Study

    Science.gov (United States)

    Karamouz, M.; Zeynolabedin, A.; Olyaei, M. A.

    2015-12-01

    Drought is among the natural disaster that causes damages and affects many people's life in many part of the world including in Iran. Recently, some factors such as climate variability and the impact of climate change have influenced drought frequency and intensity in many parts of the world. Drought can be divided into four categories of meteorological, hydrological, agricultural and social-economic. In meteorological the important feature is lack of rainfall. In hydrological drought river flows and dam storage are considered. Lack of soil moisture is the key factor in agricultural droughts while in social-economic type of drought the relation between supply and demand and social-economic damages due to water deficiency is studied. While the first three types relates to the lack of some hydrological characteristics, social-economic type of drought is actually the consequence of other types expressed in monetary values. Many indices are used in assessing drought; each has its own advantages and disadvantages and can be used for specific types of drought. Therefore knowing the types of drought can provide a better understanding of shortages and their characteristics. Drought vulnerability is a concept which shows the likelihood of damages from hazard in a particular place by focusing on the system status prior to the disaster. Drought vulnerability has been viewed as a potential for losses in the region due to water deficiency at the time of drought. In this study the application of vulnerability concept in drought management in East Azarbaijan province in Iran is investigated by providing vulnerability maps which demonstrates spatial characteristics of drought vulnerability. In the first step, certain governing parameters in drought analysis such as precipitation, temperature, land use, topography, solar radiation and ground water elevation have been investigated in the region. They are described in details and calculated in suitable time series. Vulnerabilities

  19. MAPPING REGIONAL DROUGHT VULNERABILITY: A CASE STUDY

    Directory of Open Access Journals (Sweden)

    M. Karamouz

    2015-12-01

    Full Text Available Drought is among the natural disaster that causes damages and affects many people’s life in many part of the world including in Iran. Recently, some factors such as climate variability and the impact of climate change have influenced drought frequency and intensity in many parts of the world. Drought can be divided into four categories of meteorological, hydrological, agricultural and social-economic. In meteorological the important feature is lack of rainfall. In hydrological drought river flows and dam storage are considered. Lack of soil moisture is the key factor in agricultural droughts while in social-economic type of drought the relation between supply and demand and social-economic damages due to water deficiency is studied. While the first three types relates to the lack of some hydrological characteristics, social-economic type of drought is actually the consequence of other types expressed in monetary values. Many indices are used in assessing drought; each has its own advantages and disadvantages and can be used for specific types of drought. Therefore knowing the types of drought can provide a better understanding of shortages and their characteristics. Drought vulnerability is a concept which shows the likelihood of damages from hazard in a particular place by focusing on the system status prior to the disaster. Drought vulnerability has been viewed as a potential for losses in the region due to water deficiency at the time of drought. In this study the application of vulnerability concept in drought management in East Azarbaijan province in Iran is investigated by providing vulnerability maps which demonstrates spatial characteristics of drought vulnerability. In the first step, certain governing parameters in drought analysis such as precipitation, temperature, land use, topography, solar radiation and ground water elevation have been investigated in the region. They are described in details and calculated in suitable time

  20. The current California drought through EDDI's eyes: early warning and monitoring of agricultural and hydrologic drought with the new Evaporative Demand Drought Index.

    Science.gov (United States)

    Hobbins, M.; McEvoy, D.; Huntington, J. L.; Wood, A. W.; Morton, C.; Verdin, J. P.

    2015-12-01

    hydrologic droughts, with correlations to water-year streamflow that are highest at the 9- to 12-month aggregation periods, and during the summer. EDDI shows significant promise as a leading indicator of drought, thereby providing a valuable planning window for growers and water resource managers.

  1. Drought in Southwestern United States

    Science.gov (United States)

    2007-01-01

    The southwestern United States pined for water in late March and early April 2007. This image is based on data collected by the Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite from March 22 through April 6, 2007, and it shows the Normalized Difference Vegetation Index, or NDVI, for the period. In this NDVI color scale, green indicates areas of healthier-than-usual vegetation, and only small patches of green appear in this image, near the California-Nevada border and in Utah. Larger areas of below-normal vegetation are more common, especially throughout California. Pale yellow indicates areas with generally average vegetation. Gray areas appear where no data were available, likely due to persistent clouds or snow cover. According to the April 10, 2007, update from the U.S. Drought Monitor, most of the southwestern United Sates, including Utah, Nevada, California, and Arizona, experienced moderate to extreme drought. The hardest hit areas were southeastern California and southwestern Arizona. Writing for the Drought Monitor, David Miskus of the Joint Agricultural Weather Facility reported that March 2007 had been unusually dry for the southwestern United States. While California's and Utah's reservoir storage was only slightly below normal, reservoir storage was well below normal for New Mexico and Arizona. In early April, an international research team published an online paper in Science noting that droughts could become more common for the southwestern United States and northern Mexico, as these areas were already showing signs of drying. Relying on the same computer models used in the Intergovernmental Panel on Climate Change (IPCC) report released in early 2007, the researchers who published in Science concluded that global warming could make droughts more common, not just in the American Southwest, but also in semiarid regions of southern Europe, Mediterranean northern Africa, and the Middle East.

  2. Analysis of drought areas in northern Algeria using Markov chains

    Indian Academy of Sciences (India)

    Mourad Lazri; Soltane Ameur; Michel Brucker; Maurad Lahdir; Mounir Sehad

    2015-02-01

    The present work studies the trends in drought in northern Algeria. This region was marked by a severe, wide-ranging and persistent drought due to its extraordinary rainfall deficit. In this study, drought classes are identified using SPI (standardized precipitation index) values. A Markovian approach is adopted to discern the probabilistic behaviour of the time ser ies of the drought. Thus, a transition probability matrix is constructed from drought distribution maps. The trends in changes in drought types and the distribution area are analyzed. The results show that the probability of class severe/extreme drought increases considerably rising from the probability of 0.2650 in 2005 to a stable probability of 0.5756 in 2041.

  3. Assessment of Meteorological Drought in Korea under Climate Change

    Directory of Open Access Journals (Sweden)

    Jaewon Kwak

    2016-01-01

    Full Text Available Drought has become one of the most important elements for water resources planning and management in Korea. The objective of this study is to estimate the spatial distribution of drought and change in the drought characteristics over time due to climate change. For the spatial characterization of drought, the standardized precipitation index (SPI is calculated from the 45 observatories in Korea and the spatial distribution is also estimated based on the joint probability analysis using the copula method. To analyze the effect of climate change, spatial distribution of drought in the future is analyzed using the SPI time series calculated from Representative Concentration Pathways (RCPs scenarios and HADGEM3-RA regional climate model. The results show that the Youngsan River and the northwest of Nakdong River basins in Korea have nearly doubled drought amount compared to the present and are most vulnerable to drought in near future (2016 to 2039 years.

  4. Temporal and Spatial Variability of Droughts in Southwest China from 1961 to 2012

    Directory of Open Access Journals (Sweden)

    Yaohuan Huang

    2015-10-01

    Full Text Available Southwest China (SC has suffered a series of super extreme droughts in the last decade. This study analyzed the temporal and spatial variations of drought in SC from 1961 to 2012. Based on precipitation anomaly index (PAI that was derived from 1 km gridded precipitation data, three time scales (month, year and decade for the drought frequency (DF and drought area were applied to estimate the spatio-temporal structure of droughts. A time-series analysis showed that winter droughts and spring droughts occurred frequently for almost half of the year from November to March. Summer droughts occasionally occurred in severe drought decades: the 1960s, 1980s and 2000s. During the period of observation, the percent of drought area in SC increased from the 1960s (<5% to the 2000s (>25%. A total of 57% of the area was affected by drought in 2011, when the area experienced its most severe drought both in terms of area and severity. The spatial analysis, which benefitted from the gridded data, detailed that all of SC is at drought risk except for the central Sichuan Basin. The area at high risk for severe and extreme droughts was localized in the mountains of the junction of Sichuan and Yunnan. The temporal and spatial variability can be prerequisites for drought resistance planning and drought risk management of SC.

  5. Exploring the link between meteorological drought and streamflow to inform water resource management

    Science.gov (United States)

    Lennard, Amy; Macdonald, Neil; Hooke, Janet

    2015-04-01

    Drought indicators are an under-used metric in UK drought management. Standardised drought indicators offer a potential monitoring and management tool for operational water resource management. However, the use of these metrics needs further investigation. This work uses statistical analysis of the climatological drought signal based on meteorological drought indicators and observed streamflow data to explore the link between meteorological drought and hydrological drought to inform water resource management for a single water resource region. The region, covering 21,000 km2 of the English Midlands and central Wales, includes a variety of landscapes and climatological conditions. Analysis of the links between meteorological drought and hydrological drought performed using streamflow data from 'natural' catchments indicates a close positive relationship between meteorological drought indicators and streamflow, enhancing confidence in the application of drought indicators for monitoring and management. However, many of the catchments in the region are subject to modification through impoundments, abstractions and discharge. Therefore, it is beneficial to explore how climatological drought signal propagates into managed hydrological systems. Using a longitudinal study of catchments and sub-catchments that include natural and modified river reaches the relationship between meteorological and hydrological drought is explored. Initial statistical analysis of meteorological drought indicators and streamflow data from modified catchments shows a significantly weakened statistical relationship and reveals how anthropogenic activities may alter hydrological drought characteristics in modified catchments. Exploring how meteorological drought indicators link to streamflow across the water supply region helps build an understanding of their utility for operational water resource management.

  6. Risk analysis and evaluation of agricultural drought disaster in the major grain-producing areas, China

    Directory of Open Access Journals (Sweden)

    Zongtang Xie

    2016-09-01

    Full Text Available The analysis and evaluation of agricultural drought risk can assist in reducing regional disasters and agricultural drought losses. Because of the uncertainties and incomplete agricultural drought information, this paper employed an information diffusion technology and information matrix to identify a drought disaster risk distribution and to quantify the relationship between the annual drought-affected rate and the grain production losses in China's major grain-producing areas. From the assessment results, provincial drought disaster risk spatial distribution maps for each major grain-producing area in China were obtained. These risk patterns showed that the probability of drought fell when the annual drought-covered rate and the annual drought-affected rate increased, and that the high risk areas were located primarily in China's northern and central provinces. These results can provide the basis for the development of effective drought mitigation strategies which would be able to inform possible drought situations and allow for easier decision-making on drought resistance strategies. The fuzzy relationship between the annual drought-affected rate and the drought-caused grain production losses provides vital information for the development of disaster compensation plans. Furthermore, the results of this study indicated that the proposed methods had superior detection stability and higher precision. We hope that by conducting such agricultural drought risk analysis, the results are able to provide the basis for the development of drought mitigation strategies to reduce future losses.

  7. Drought risk on a pan European scale: integrating the missing piece

    Science.gov (United States)

    Blauhut, Veit; Stahl, Kerstin

    2015-04-01

    The effects of drought on the environment and socio- economic sectors are indisputably linked to each other. Nevertheless, past drought research suffered from an evident lack of ground truth in form of past observed impacts. Consequently most drought indicators are missing the link to a drought's effects on natural and human systems, and the majority of drought risk analyses are based on non-sector-specific, epistemic approaches. Hence, the science and application demands an integration of the missing piece: past drought impacts. Furthermore, for the case of Europe, drought risk analyses are mainly done for country scale or smaller units, even though the effects of the drought hazard are transboundary and long term measures are initiated through the European governance mechanism. This contribution faces drought risk on a pan European scale. A spatio-temporal clustering of drought impact occurrences from the European Drought Impact report Inventory divides Europe into macro regions with similar drought impact characteristics. To link drought impacts to indicators and vulnerability factors, multivariate logistic regression is applied to predict the likelihood of impact occurrence as a proxy for drought risk. As predictive variables we used a selection of common drought indicators and drought vulnerability analysis factors. The final results are displayed as drought risk maps, presenting drought risk for different levels of hazard severity, showing distinct differences in drought risk depending on location and impact sector. With this work, we contribute to the understanding of feedbacks between drought and society. The knowledge of this relation is essential for drought impact predictions and will improve resilience to this hazard. Furthermore, this information may become an essential tool for policy and decision makers on a European level.

  8. Spatial comparability of drought characteristics and related return periods in mainland China over 1961-2013

    Science.gov (United States)

    Ayantobo, Olusola O.; Li, Yi; Song, Songbai; Yao, Ning

    2017-07-01

    The proper understanding of the spatiotemporal characteristics of multi-year droughts and return periods is important for drought risk assessment. This study evaluated and compared the spatiotemporal variations of drought characteristics and return periods within mainland China between 1961 and 2013. Standardized Precipitation Index (SPI), Standardized Precipitation Evapotranspiration Index (SPEI) and Composite Index (CI) were calculated at multiple timescales, the run theory was used for objective identification and characterization of drought events while Kendall's τ method was used to analyze their dependencies. Within the univariate framework, marginal distributions of duration, severity, and peak were derived by fitting Exponential, Weibull and GDP distributions respectively and the drought return periods was investigated and mapped. Comparison of drought indices showed that SPEI and CI performed better than SPI in delineating spatial patterns of drought characteristics. This might be attributed to the temperature effect on evapotranspiration and therefore on drought index. Considering the increasing trend in reference evapotranspiration in the 21st century, the importance of utilizing temperature-based drought index is imperative. Severe and extreme droughts occurred in the late 1990s in many places in China while persistent multi-year severe droughts occurred more frequently over North China, Northeast China, Northwest China and Southwest China. The spatial patterns showed that regions characterized by higher drought severity were associated with higher drought duration. The North China, Northwest China, and Southwest China had much longer drought durations during the 1990s and 2000s. As droughts normally cover large areas, regional drought return periods has been showed to be more effective in providing support for drought management than station based drought return periods. Studies on the spatial comparability of drought return periods across mainland

  9. Modeling drought impact occurrence based on climatological drought indices for four European countries

    Science.gov (United States)

    Stagge, James H.; Kohn, Irene; Tallaksen, Lena M.; Stahl, Kerstin

    2014-05-01

    The relationship between atmospheric conditions and the likelihood of a significant drought impact has, in the past, been difficult to quantify, particularly in Europe where political boundaries and language have made acquiring comprehensive drought impact information difficult. As such, the majority of studies linking meteorological drought with the occurrence or severity of drought impacts have previously focused on specific regions, very detailed impact types, or both. This study describes a new methodology to link the likelihood of drought impact occurrence with climatological drought indices across different European climatic regions and impact sectors using the newly developed European Drought Impact report Inventory (EDII), a collaborative database of drought impact information (www.geo.uio.no/edc/droughtdb/). The Standardized Precipitation Index (SPI) and Standardized Precipitation-Evapotranspiration Index (SPEI) are used as predictor variables to quantify meteorological drought severity over prior time periods (here 1, 2, 3, 6, 9, 12, and 24 months are used). The indices are derived using the gridded WATCH Forcing Datasets, covering the period 1958-2012. Analysis was performed using logistic regression to identify the climatological drought index and accumulation period, or linear combination of drought indices, that best predicts the likelihood of a documented drought impact, defined by monthly presence/absence. The analysis was carried out for a subset of four European countries (Germany, UK, Norway, Slovenia) and four of the best documented impact sectors: Public Water Supply, Agriculture and Livestock Farming, Energy and Industry, and Environmental Quality. Preliminary results show that drought impacts in these countries occur most frequently due to a combination of short-term (2-6 month) precipitation deficits and long-term (12-24 month) potential evapotranspiration anomaly, likely associated with increased temperatures. Agricultural drought impacts

  10. Groundwater potential for water supply during droughts in Korea

    Science.gov (United States)

    Hyun, Y.; Cha, E.; Moon, H. J.

    2016-12-01

    Droughts have been receiving much attention in Korea because severe droughts occurred in recent years, causing significant social, economic and environmental damages in some regions. Residents in agricultural area, most of all, were most damaged by droughts with lack of available water supplies to meet crop water demands. In order to mitigate drought damages, we present a strategy to keep from agricultural droughts by using groundwater to meet water supply as a potential water resource in agricultural areas. In this study, we analyze drought severity and the groundwater potential to mitigate social and environmental damages caused by droughts in Korea. We evaluate drought severity by analyzing spatial and temporal meteorological and hydrological data such as rainfall, water supply and demand. For drought severity, we use effective drought index along with the standardized precipitation index (SPI) and standardized runoff index(SRI). Water deficit during the drought period is also quantified to consider social and environmental impact of droughts. Then we assess the feasibility of using groundwater as a potential source for groundwater impact mitigation. Results show that the agricultural areas are more vulnerable to droughts and use of groundwater as an emergency water resource is feasible in some regions. For a case study, we select Jeong-Sun area located in Kangwon providence having well-developed Karst aquifers and surrounded by mountains. For Jeong-Sun area, we quantify groundwater potential use, design the method of water supply by using groundwater, and assess its economic benefit. Results show that water supply system with groundwater abstraction can be a good strategy when droughts are severe for an emergency water supply in Jeong-Sun area, and groundwater can also be used not only for a dry season water supply resource, but for everyday water supply system. This case study results can further be applicable to some regions with no sufficient water

  11. SDI and Markov Chains for Regional Drought Characteristics

    Directory of Open Access Journals (Sweden)

    Chen-Feng Yeh

    2015-08-01

    Full Text Available In recent years, global climate change has altered precipitation patterns, causing uneven spatial and temporal distribution of precipitation that gradually induces precipitation polarization phenomena. Taiwan is located in the subtropical climate zone, with distinct wet and dry seasons, which makes the polarization phenomenon more obvious; this has also led to a large difference between river flows during the wet and dry seasons, which is significantly influenced by precipitation, resulting in hydrological drought. Therefore, to effectively address the growing issue of water shortages, it is necessary to explore and assess the drought characteristics of river systems. In this study, the drought characteristics of northern Taiwan were studied using the streamflow drought index (SDI and Markov chains. Analysis results showed that the year 2002 was a turning point for drought severity in both the Lanyang River and Yilan River basins; the severity of rain events in the Lanyang River basin increased after 2002, and the severity of drought events in the Yilan River basin exhibited a gradual upward trend. In the study of drought severity, analysis results from periods of three months (November to January and six months (November to April have shown significant drought characteristics. In addition, analysis of drought occurrence probabilities using the method of Markov chains has shown that the occurrence probabilities of drought events are higher in the Lanyang River basin than in the Yilan River basin; particularly for extreme events, the occurrence probability of an extreme drought event is 20.6% during the dry season (November to April in the Lanyang River basin, and 3.4% in the Yilan River basin. This study shows that for analysis of drought/wet occurrence probabilities, the results obtained for the drought frequency and occurrence probability using short-term data with the method of Markov chains can be used to predict the long-term occurrence

  12. Drought monitoring with soil moisture active passive (SMAP) measurements

    Science.gov (United States)

    Mishra, Ashok; Vu, Tue; Veettil, Anoop Valiya; Entekhabi, Dara

    2017-09-01

    Recent launch of space-borne systems to estimate surface soil moisture may expand the capability to map soil moisture deficit and drought with global coverage. In this study, we use Soil Moisture Active Passive (SMAP) soil moisture geophysical retrieval products from passive L-band radiometer to evaluate its applicability to forming agricultural drought indices. Agricultural drought is quantified using the Soil Water Deficit Index (SWDI) based on SMAP and soil properties (field capacity and available water content) information. The soil properties are computed using pedo-transfer function with soil characteristics derived from Harmonized World Soil Database. The SMAP soil moisture product needs to be rescaled to be compatible with the soil parameters derived from the in situ stations. In most locations, the rescaled SMAP information captured the dynamics of in situ soil moisture well and shows the expected lag between accumulations of precipitation and delayed increased in surface soil moisture. However, the SMAP soil moisture itself does not reveal the drought information. Therefore, the SMAP based SWDI (SMAP_SWDI) was computed to improve agriculture drought monitoring by using the latest soil moisture retrieval satellite technology. The formulation of SWDI does not depend on longer data and it will overcome the limited (short) length of SMAP data for agricultural drought studies. The SMAP_SWDI is further compared with in situ Atmospheric Water Deficit (AWD) Index. The comparison shows close agreement between SMAP_SWDI and AWD in drought monitoring over Contiguous United States (CONUS), especially in terms of drought characteristics. The SMAP_SWDI was used to construct drought maps for CONUS and compared with well-known drought indices, such as, AWD, Palmer Z-Index, sc-PDSI and SPEI. Overall the SMAP_SWDI is an effective agricultural drought indicator and it provides continuity and introduces new spatial mapping capability for drought monitoring. As an

  13. Drought risk reduction

    NARCIS (Netherlands)

    Su, Z.; Roerink, G.J.

    2004-01-01

    Due to the shortage of water resources and its inhomogeneous distribution in space and time, large scale droughts occur frequently all over the world. Consequently, drought has become a key factor constraining the economic development and threatening the food security. This report describes the resu

  14. Drought Tolerance in Wheat

    Directory of Open Access Journals (Sweden)

    Arash Nezhadahmadi

    2013-01-01

    Full Text Available Drought is one of the most important phenomena which limit crops’ production and yield. Crops demonstrate various morphological, physiological, biochemical, and molecular responses to tackle drought stress. Plants’ vegetative and reproductive stages are intensively influenced by drought stress. Drought tolerance is a complicated trait which is controlled by polygenes and their expressions are influenced by various environmental elements. This means that breeding for this trait is so difficult and new molecular methods such as molecular markers, quantitative trait loci (QTL mapping strategies, and expression patterns of genes should be applied to produce drought tolerant genotypes. In wheat, there are several genes which are responsible for drought stress tolerance and produce different types of enzymes and proteins for instance, late embryogenesis abundant (lea, responsive to abscisic acid (Rab, rubisco, helicase, proline, glutathione-S-transferase (GST, and carbohydrates during drought stress. This review paper has concentrated on the study of water limitation and its effects on morphological, physiological, biochemical, and molecular responses of wheat with the possible losses caused by drought stress.

  15. USGS integrated drought science

    Science.gov (United States)

    Ostroff, Andrea C.; Muhlfeld, Clint C.; Lambert, Patrick M.; Booth, Nathaniel L.; Carter, Shawn L.; Stoker, Jason M.; Focazio, Michael J.

    2017-06-05

    Project Need and OverviewDrought poses a serious threat to the resilience of human communities and ecosystems in the United States (Easterling and others, 2000). Over the past several years, many regions have experienced extreme drought conditions, fueled by prolonged periods of reduced precipitation and exceptionally warm temperatures. Extreme drought has far-reaching impacts on water supplies, ecosystems, agricultural production, critical infrastructure, energy costs, human health, and local economies (Milly and others, 2005; Wihlite, 2005; Vörösmarty and others, 2010; Choat and others, 2012; Ledger and others, 2013). As global temperatures continue to increase, the frequency, severity, extent, and duration of droughts are expected to increase across North America, affecting both humans and natural ecosystems (Parry and others, 2007).The U.S. Geological Survey (USGS) has a long, proven history of delivering science and tools to help decision-makers manage and mitigate effects of drought. That said, there is substantial capacity for improved integration and coordination in the ways that the USGS provides drought science. A USGS Drought Team was formed in August 2016 to work across USGS Mission Areas to identify current USGS drought-related research and core capabilities. This information has been used to initiate the development of an integrated science effort that will bring the full USGS capacity to bear on this national crisis.

  16. Wheat Drought-Responsive Grain Proteome Analysis by Linear and Nonlinear 2-DE and MALDI-TOF Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Wu-Jun Ma

    2012-11-01

    Full Text Available A comparative proteomic analysis of drought-responsive proteins during grain development of two wheat varieties Kauz (strong resistance to drought stress and Janz (sensitive to drought stress was performed by using linear and nonlinear 2-DE and MALDI-TOF mass spectrometry technologies. Results revealed that the nonlinear 2-DE had much higher resolution than the linear 2-DE. A total of 153 differentially expressed protein spots were detected by both 2-DE maps, of which 122 protein spots were identified by MALDI-TOF and MALDI-TOF/TOF mass spectrometry. The identified differential proteins were mainly involved in carbohydrate metabolism (26%, detoxification and defense (23%, and storage proteins (17%. Some key proteins demonstrated significantly different expression patterns between the two varieties. In particular, catalase isozyme 1, WD40 repeat protein, LEA and alpha-amylase inhibitors displayed an upregulated expression pattern in Kauz, whereas they were downregulated or unchanged in Janz. Small and large subunit ADP glucose pyrophosphorylase, ascorbate peroxidase and G beta-like protein were all downregulated under drought stress in Janz, but had no expression changes in Kauz. Sucrose synthase and triticin precursor showed an upregulated expression pattern under water deficits in both varieties, but their upregulation levels were much higher in Kauz than in Janz. These differentially expressed proteins could be related to the biochemical pathways for stronger drought resistance of Kauz.

  17. Comparison of two drought indices in studying regional meteorological drought events in China

    Science.gov (United States)

    Wang, Yongmei; Ren, Fumin; Zhao, Yilei; Li, Yunjie

    2017-02-01

    The composite-drought index (CI), improved weighted average of precipitation index (IWAP), and the objective identification technique for regional extreme events (OITREE) were employed to detect China's regional meteorological drought events (CRMDEs) during 1961-2010. Compared with existing references, CI and IWAP both showed strong ability in identifying CRMDEs. Generally, the results of CI and IWAP were consistent, especially for extreme and severe CRMDEs. During 1961-2010, although the frequencies of extreme and severe CRMDEs based on CI and IWAP both showed weak decreasing trends, the two mean-integrated indices both showed increasing but not significant trends. However, the results of IWAP were more reasonable than CI's in two aspects. Firstly, the monthly frequency of extreme and severe CRMDEs based on IWAP showed a clear seasonal variation, which coincided with the seasonal variation of the East Asian monsoon over central-eastern China, whereas the frequency based on CI presented a much weaker seasonal variation. Secondly, the two sets of results were sometimes inconsistent with respect to the start and end times of a CRMDE, and CRMDEs based on CI generally showed two unreasonable phenomena: (1) under non-drought conditions, a severe drought stage could suddenly occur in a large area; and (2) during the following period, drought could alleviate gradually in cases of non-precipitation. Comparative analysis suggested that the IWAP drought index possesses obvious advantages in detecting and monitoring regional drought events.

  18. Comparison between Two Methods for agricultural drought disaster risk in southwestern China

    Science.gov (United States)

    han, lanying; zhang, qiang

    2016-04-01

    The drought is a natural disaster, which lead huge loss to agricultural yield in the world. The drought risk has become increasingly prominent because of the climatic warming during the past century, and which is also one of the main meteorological disasters and serious problem in southwestern China, where drought risk exceeds the national average. Climate change is likely to exacerbate the problem, thereby endangering Chinaʹs food security. In this paper, drought disaster in the southwestern China (where there are serious drought risk and the comprehensive loss accounted for 3.9% of national drought area) were selected to show the drought change under climate change, and two methods were used to assess the drought disaster risk, drought risk assessment model and comprehensive drought risk index. Firstly, we used the analytic hierarchy process and meteorological, geographic, soil, and remote-sensing data to develop a drought risk assessment model (defined using a comprehensive drought disaster risk index, R) based on the drought hazard, environmental vulnerability, sensitivity and exposure of the values at risk, and capacity to prevent or mitigate the problem. Second, we built the comprehensive drought risk index (defined using a comprehensive drought disaster loss, L) based on statistical drought disaster data, including crop yields, drought-induced areas, drought-occurred areas, no harvest areas caused by drought and planting areas. Using the model, we assessed the drought risk. The results showed that spatial distribution of two drought disaster risks were coherent, and revealed complex zonality in southwestern China. The results also showed the drought risk is becoming more and more serious and frequent in the country under the global climatic warming background. The eastern part of the study area had an extremely high risk, and risk was generally greater in the north than in the south, and increased from southwest to northeast. The drought disaster risk or

  19. Responses of nitrogen metabolism and seed nutrition to drought stress in soybean genotypes differing in slow-wilting phenotype

    Directory of Open Access Journals (Sweden)

    Nacer eBellaloui

    2013-12-01

    Full Text Available Recent advances in soybean breeding have resulted in genotypes that express the slow-wilting phenotype (trait under drought stress conditions. The physiological mechanisms of this trait remain unknown due to the complexity of trait × environment interactions. The objective of this research was to investigate nitrogen metabolism and leaf and seed nutrients composition of the slow-wilting soybean genotypes under drought stress conditions. A repeated greenhouse experiment was conducted using check genotypes: NC-Roy (fast wilting, Boggs (intermediate in wilting; and NTCPR94-5157 and N04-9646 (slow-wilting, SLW genotypes. Plants were either well-watered or drought stressed. Results showed that under well-watered conditions, nitrogen fixation (NF, nitrogen assimilation (NA, and leaf and seed composition differed between genotypes. Under drought stress, NF and NA were higher in NTCPR94-5157 and N04-9646 than in NC-Roy and Boggs. Under severe water stress, however, NA was low in all genotypes. Leaf water potential was significantly lower in checks (-2.00 MPa than in the SLW genotypes (-1.68 MPa. Leaf and seed concentrations of K, P, Ca, Cu, Na, B were higher in SLW genotypes than in the checks under drought stress conditions. Seed protein, oleic acid, and sugars were higher in SLW genotypes, and oil, linoleic and linolenic acids were lower in SLW genotypes. This research demonstrated that K, P, Ca, Cu, Na, and B may be involved in SLW trait by maintaining homeostasis and osmotic regulation. Maintaining higher leaf water potential in NTCPR94-5157 and N04-9646 under drought stress could be a possible water conservation mechanism to maintain leaf turgor pressure. The increase in osmoregulators such as minerals, raffinose and stachyose, and oleic acid could be beneficial for soybean breeders in selecting for drought stress tolerance.

  20. Projected seasonal meteorological droughts over Europe until 2100

    Science.gov (United States)

    Spinoni, Jonathan; Vogt, Jürgen; Naumann, Gustavo; Barbosa, Paulo; Dosio, Alessandro

    2017-04-01

    In the last decades, droughts have become increasingly recurrent and intense over large areas of Europe. Due to the projected temperature increase and longer dry periods, meteorological droughts are expected to become more frequent and severe in the next decades, potentially causing relevant impacts in many economic sectors and the environment. To investigate future drought patterns over Europe, we computed a combined indicator based on the Standardized Precipitation Index (SPI), the Standardized Precipitation-Evapotranspiration Index (SPEI), and the Reconnaissance Drought Indicator (RDI). All indicators were computed at a 3-month accumulation period to focus on seasonal droughts using temperature and precipitation from an ensemble of eleven bias-adjusted simulations from the EURO-CORDEX experiment as input data. The combined indicator focuses on the predominance of drought conditions over normal conditions and was applied to obtain frequency and severity of drought events at 0.11° spatial resolution over Europe from 1981 to 2100. The analysis was performed for two representative concentration pathways (RCP), the moderate emission scenario RCP4.5 and the extreme RCP8.5. Excluding winter droughts, which are likely to be less frequent and severe over Central and Northern Europe for both scenarios, the other seasons show increased drought frequency and severity over entire Europe, markedly larger as the century passes especially under the RCP8.5. The largest increases are projected for spring droughts over the Iberian Peninsula and North-Eastern Scandinavia and for summer droughts over Western Europe. Under the RCP8.5, at least six out of eleven simulations project a statistically significant positive trend from 1981 to 2100 of drought frequency for the Mediterranean area, the Iberian Peninsula, and Turkey. On an annual scale, most simulations project a continuous increase of both drought frequency and severity for entire Europe, excluding Iceland and Central

  1. Drought - A Global Assessment

    Science.gov (United States)

    Lackner, S.; Barnwal, P.; von der Goltz, J.

    2013-12-01

    We investigate the lasting effects of early childhood exposure to drought on economic and health outcomes in a large multi-country dataset. By pooling all Demographic and Health Survey rounds for which household geocodes are available, we obtain an individual-level dataset covering 47 developing countries. Among other impact measures, we collect infant and child mortality data from 3.3m live births and data on stunting and wasting for 1.2m individuals, along with data on education, employment, wealth, marriage and childbearing later in life for similarly large numbers of respondents. Birth years vary from 1893 to 2012. We seek to improve upon existing work on the socio-economic impact of drought in a number of ways. First, we introduce from the hydrological literature a drought measure, the Standardized Precipitation Index (SPI), that has been shown to closely proxy the Palmer drought index, but has far less demanding data requirements, and can be obtained globally and for long time periods. We estimate the SPI for 110 years on a global 0.5° grid, which allows us to assign drought histories to the geocoded individual data. Additionally, we leverage our large sample size to explicitly investigate both how drought impacts have changed over time as adaptation occurred at a varying pace in different locations, and the role of the regional extent of drought in determining impacts.

  2. Monitoring drought in the Monglian Plateau based on NDVI_Ts general space, 2000-2010

    Science.gov (United States)

    Cao, Xiaoming; Wang, Juanle; Gao, Zhiqiang; Ning, Jicai; Shi, Runhe; Gao, Wei

    2013-09-01

    This paper presents a new drought assessment method by modifying the NDVI-Ts space, which named NDVI-Ts general space. Based on this method, the general dry side and wet side equation were established for the period of 2000 and 2010 in the Mongolian Plateau. The results showed that: 1) the NDVI-Ts general space was more stable for monitoring drought than that for the single time Remote Sensing data; 2) Drought mainly distributed in the Mongolian Plateau, In Mongolian Plateau, there was about 75% area of drought; 3) Drought changed in the period of 2000 and 2010. In the year of 2003, the area of severe drought is the smallest. In 2001, the drought is the most serious. The results showed that, the distribution of drought was different in different year. There may be close correlation between the occurrence of drought and precipitation.

  3. Deployment Repeatability

    Science.gov (United States)

    2016-04-01

    controlled to great precision, but in a Cubesat , there may be no attitude determination at all. Such a Cubesat might treat sun angle and tumbling rates as...could be sensitive to small differences in motor controller timing. In these cases, the analyst might choose to model the entire deployment path, with...knowledge of the material damage model or motor controller timing precision. On the other hand, if many repeated and environmentally representative

  4. Evaluation of common bean (Phaseolus vulgaris L. genotypes for drought stress adaptation in Ethiopia

    Directory of Open Access Journals (Sweden)

    Kwabena Darkwa

    2016-10-01

    Full Text Available Drought stress linked with climate change is one of the major constraints faced by common bean farmers in Africa and elsewhere. Mitigating this constraint requires the selection of resilient varieties that withstand drought threats to common bean production. This study assessed the drought response of 64 small red-seeded genotypes of common bean grown in a lattice design replicated twice under contrasting moisture regimes, terminal drought stress and non-stress, in Ethiopia during the dry season from November 2014 to March 2015. Multiple plant traits associated with drought were assessed for their contribution to drought adaptation of the genotypes. Drought stress determined by a drought intensity index was moderate (0.3. All the assessed traits showed significantly different genotypic responses under drought stress and non-stress conditions. Eleven genotypes significantly (P ≤ 0.05 outperformed the drought check cultivar under both drought stress and non-stress conditions in seed yielding potential. Seed yield showed positive and significant correlations with chlorophyll meter reading, vertical root pulling resistance force, number of pods per plant, and seeds per pod under both soil moisture regimes, indicating their potential use in selection of genotypes yielding well under drought stress and non-stress conditions. Clustering analysis using Mahalanobis distance grouped the genotypes into four groups showing high and significant inter-cluster distance, suggesting that hybridization between drought-adapted parents from the groups will provide the maximum genetic recombination for drought tolerance in subsequent generations.

  5. Evaluation of common bean (Phaseolus vulgaris L.) genotypes for drought stress adaptation in Ethiopia

    Institute of Scientific and Technical Information of China (English)

    Kwabena Darkwa; Daniel Ambachewa; Hussein Mohammed; Asrat Asfaw; Matthew W. Blairc

    2016-01-01

    Drought stress linked with climate change is one of the major constraints faced by common bean farmers in Africa and elsewhere. Mitigating this constraint requires the selection of resilient varieties that withstand drought threats to common bean production. This study assessed the drought response of 64 small red-seeded genotypes of common bean grown in a lattice design replicated twice under contrasting moisture regimes, terminal drought stress and non-stress, in Ethiopia during the dry season from November 2014 to March 2015. Multiple plant traits associated with drought were assessed for their contribution to drought adaptation of the genotypes. Drought stress determined by a drought intensity index was moderate (0.3). All the assessed traits showed significantly different genotypic responses under drought stress and non-stress conditions. Eleven genotypes significantly (P ≤0.05) outperformed the drought check cultivar under both drought stress and non-stress conditions in seed yielding potential. Seed yield showed positive and significant correlations with chlorophyll meter reading, vertical root pulling resistance force, number of pods per plant, and seeds per pod under both soil moisture regimes, indicating their potential use in selection of genotypes yielding well under drought stress and non-stress conditions. Clustering analysis using Mahalanobis distance grouped the genotypes into four groups showing high and significant inter-cluster distance, suggesting that hybridization between drought-adapted parents from the groups will provide the maximum genetic recombination for drought tolerance in subsequent generations.

  6. An extended multivariate framework for drought monitoring in Mexico

    Science.gov (United States)

    Real-Rangel, Roberto; Pedrozo-Acuña, Adrián; Breña-Naranjo, Agustín; Alcocer-Yamanaka, Víctor

    2017-04-01

    Around the world, monitoring natural hazards, such as droughts, represents a critical task in risk assessment and management plans. A reliable drought monitoring system allows to identify regions affected by these phenomena so that early response measures can be implemented. In Mexico, this activity is performed using Mexico's Drought Monitor, which is based on a similar methodology as the United States Drought Monitor and the North American Drought Monitor. The main feature of these monitoring systems is the combination of ground-based and remote sensing observations that is ultimately validated by local experts. However, in Mexico in situ records of variables such as precipitation and streamflow are often scarce, or even null, in many regions of the country. Another issue that adds uncertainty in drought monitoring is the arbitrary weight given to each analyzed variable. This study aims at providing an operational framework for drought monitoring in Mexico, based on univariate and multivariate nonparametric standardized indexes proposed in recent studies. Furthermore, the framework has been extended by taking into account the Enhanced Vegetation Index (EVI) for the drought severity assessment. The analyzed variables used for computing the drought indexes are mainly derived from remote sensing (MODIS) and land surface models datasets (NASA MERRA-2). A qualitative evaluation of the results shows that the indexes used are capable of adequately describes the intensity and spatial distribution of past drought documented events.

  7. The complex influence of ENSO on droughts in Ecuador

    Science.gov (United States)

    Vicente-Serrano, S. M.; Aguilar, E.; Martínez, R.; Martín-Hernández, N.; Azorin-Molina, C.; Sanchez-Lorenzo, A.; El Kenawy, A.; Tomás-Burguera, M.; Moran-Tejeda, E.; López-Moreno, J. I.; Revuelto, J.; Beguería, S.; Nieto, J. J.; Drumond, A.; Gimeno, L.; Nieto, R.

    2017-01-01

    In this study, we analyzed the influence of El Niño-Southern Oscillation (ENSO) on the spatio-temporal variability of droughts in Ecuador for a 48-year period (1965-2012). Droughts were quantified from 22 high-quality and homogenized time series of precipitation and air temperature by means of the Standardized Precipitation Evapotranspiration Index. In addition, the propagation of two different ENSO indices (El Niño 3.4 and El Niño 1 + 2 indices) and other atmospheric circulation processes (e.g., vertical velocity) on different time-scales of drought severity were investigated. The results showed a very complex influence of ENSO on drought behavior across Ecuador, with two regional patterns in the evolution of droughts: (1) the Andean chain with no changes in drought severity, and (2) the Western plains with less severe and frequent droughts. We also detected that drought variability in the Andes mountains is explained by the El Niño 3.4 index [sea surface temperature (SST) anomalies in the central Pacific], whereas the Western plains are much more driven by El Niño 1 + 2 index (SST anomalies in the eastern Pacific). Moreover, it was also observed that El Niño and La Niña phases enhance droughts in the Andes and Western plains regions, respectively. The results of this work could be crucial for predicting and monitoring drought variability and intensity in Ecuador.

  8. Assessing the utility of meteorological drought indices in monitoring summer drought based on soil moisture in Chongqing, China

    Science.gov (United States)

    Chen, Hui; Wu, Wei; Liu, Hong-Bin

    2017-04-01

    Numerous drought indices have been developed to analyze and monitor drought condition, but they are region specific and limited by various climatic conditions. In southwest China, summer drought mainly occurs from June to September, causing destructive and profound impact on agriculture, society, and ecosystems. The current study assesses the availability of meteorological drought indices in monitoring summer drought in this area at 5-day scale. The drought indices include the relative moisture index (M), the standardized precipitation index (SPI), the standardized precipitation evapotranspiration index (SPEI), the composite index of meteorological drought (CIspi), and the improved composite index of meteorological drought (CIwap). Long-term daily precipitation and temperature from 1970 to 2014 are used to calculate 30-day M (M 30), SPI (SPI30), SPEI (SPEI30), 90-day SPEI (SPEI90), CIspi, and CIwap. The 5-day soil moisture observations from 2010 to 2013 are applied to assess the performance of these drought indices. Correlation analysis, overall accuracy, and kappa coefficient are utilized to investigate the relationships between soil moisture and drought indices. Correlation analysis indicates that soil moisture is well correlated with CIwap, SPEI30, M 30, SPI30, and CIspi except SPEI90. Moreover, drought classifications identified by M 30 are in agreement with that of the observed soil moisture. The results show that M 30 based on precipitation and potential evapotranspiration is an appropriate indicator for monitoring drought condition at a finer scale in the study area. According to M 30, summer drought during 1970-2014 happened in each year and showed a slightly upward tendency in recent years.

  9. Risk identification of agricultural drought for sustainable Agroecosystems

    Science.gov (United States)

    Dalezios, N. R.; Blanta, A.; Spyropoulos, N. V.; Tarquis, A. M.

    2014-09-01

    Drought is considered as one of the major natural hazards with a significant impact on agriculture, environment, society and economy. Droughts affect sustainability of agriculture and may result in environmental degradation of a region, which is one of the factors contributing to the vulnerability of agriculture. This paper addresses agrometeorological or agricultural drought within the risk management framework. Risk management consists of risk assessment, as well as a feedback on the adopted risk reduction measures. And risk assessment comprises three distinct steps, namely risk identification, risk estimation and risk evaluation. This paper deals with risk identification of agricultural drought, which involves drought quantification and monitoring, as well as statistical inference. For the quantitative assessment of agricultural drought, as well as the computation of spatiotemporal features, one of the most reliable and widely used indices is applied, namely the vegetation health index (VHI). The computation of VHI is based on satellite data of temperature and the normalized difference vegetation index (NDVI). The spatiotemporal features of drought, which are extracted from VHI, are areal extent, onset and end time, duration and severity. In this paper, a 20-year (1981-2001) time series of the National Oceanic and Atmospheric Administration/advanced very high resolution radiometer (NOAA/AVHRR) satellite data is used, where monthly images of VHI are extracted. Application is implemented in Thessaly, which is the major agricultural drought-prone region of Greece, characterized by vulnerable agriculture. The results show that agricultural drought appears every year during the warm season in the region. The severity of drought is increasing from mild to extreme throughout the warm season, with peaks appearing in the summer. Similarly, the areal extent of drought is also increasing during the warm season, whereas the number of extreme drought pixels is much less than

  10. Risk identification of agricultural drought for sustainable agroecosystems

    Directory of Open Access Journals (Sweden)

    N. R. Dalezios

    2014-04-01

    Full Text Available Drought is considered as one of the major natural hazards with significant impact to agriculture, environment, society and economy. Droughts affect sustainability of agriculture and may result in environmental degradation of a region, which is one of the factors contributing to the vulnerability of agriculture. This paper addresses agrometeorological or agricultural drought within the risk management framework. Risk management consists of risk assessment, as well as a feedback on the adopted risk reduction measures. And risk assessment comprises three distinct steps, namely risk identification, risk estimation and risk evaluation. This paper deals with risk identification of agricultural drought, which involves drought quantification and monitoring, as well as statistical inference. For the quantitative assessment of agricultural drought, as well as the computation of spatiotemporal features, one of the most reliable and widely used indices is applied, namely the Vegetation Health Index (VHI. The computation of VHI is based on satellite data of temperature and the Normalized Difference Vegetation Index (NDVI. The spatiotemporal features of drought, which are extracted from VHI are: areal extent, onset and end time, duration and severity. In this paper, a 20 year (1981–2001 time series of NOAA/AVHRR satellite data is used, where monthly images of VHI are extracted. Application is implemented in Thessaly, which is the major agricultural drought-prone region of Greece, characterized by vulnerable agriculture. The results show that agricultural drought appears every year during the warm season in the region. The severity of drought is increasing from mild to extreme throughout the warm season with peaks appearing in the summer. Similarly, the areal extent of drought is also increasing during the warm season, whereas the number of extreme drought pixels is much less than those of mild to moderate drought throughout the warm season. Finally, the

  11. Amazon forests green-up during 2005 drought.

    Science.gov (United States)

    Saleska, Scott R; Didan, Kamel; Huete, Alfredo R; da Rocha, Humberto R

    2007-10-26

    Coupled climate-carbon cycle models suggest that Amazon forests are vulnerable to both long- and short-term droughts, but satellite observations showed a large-scale photosynthetic green-up in intact evergreen forests of the Amazon in response to a short, intense drought in 2005. These findings suggest that Amazon forests, although threatened by human-caused deforestation and fire and possibly by more severe long-term droughts, may be more resilient to climate changes than ecosystem models assume.

  12. Density-dependent vulnerability of forest ecosystems to drought

    Science.gov (United States)

    Bottero, Alessandra; D'Amato, Anthony W.; Palik, Brian J.; Bradford, John B.; Fraver, Shawn; Battaglia, Mike A.; Asherin, Lance A.

    2017-01-01

    1. Climate models predict increasing drought intensity and frequency for many regions, which may have negative consequences for tree recruitment, growth and mortality, as well as forest ecosystem services. Furthermore, practical strategies for minimizing vulnerability to drought are limited. Tree population density, a metric of tree abundance in a given area, is a primary driver of competitive intensity among trees, which influences tree growth and mortality. Manipulating tree population density may be a mechanism for moderating drought-induced stress and growth reductions, although the relationship between tree population density and tree drought vulnerability remains poorly quantified, especially across climatic gradients.2. In this study, we examined three long-term forest ecosystem experiments in two widely distributed North American pine species, ponderosa pine Pinus ponderosa (Lawson & C. Lawson) and red pine Pinus resinosa (Aiton), to better elucidate the relationship between tree population density, growth and drought. These experiments span a broad latitude and aridity range and include tree population density treatments that have been purposefully maintained for several decades. We investigated how tree population density influenced resistance (growth during drought) and resilience (growth after drought compared to pre-drought growth) of stand-level growth during and after documented drought events.3. Our results show that relative tree population density was negatively related to drought resistance and resilience, indicating that trees growing at lower densities were less vulnerable to drought. This result was apparent in all three forest ecosystems, and was consistent across species, stand age and drought intensity.4. Synthesis and applications. Our results highlighted that managing pine forest ecosystems at low tree population density represents a promising adaptive strategy for reducing the adverse impacts of drought on forest growth in coming decades

  13. The impact of climate mitigation on projections of future drought

    Directory of Open Access Journals (Sweden)

    I. H. Taylor

    2013-06-01

    Full Text Available Drought is a cumulative event, often difficult to define and involving wide-reaching consequences for agriculture, ecosystems, water availability, and society. Understanding how the occurrence of drought may change in the future and which sources of uncertainty are dominant can inform appropriate decisions to guide drought impacts assessments. Our study considers both climate model uncertainty associated with future climate projections, and future emissions of greenhouse gases (future scenario uncertainty. Four drought indices (the Standardised Precipitation Index (SPI, Soil Moisture Anomaly (SMA, the Palmer Drought Severity Index (PDSI and the Standardised Runoff Index (SRI are calculated for the A1B and RCP2.6 future emissions scenarios using monthly model output from a 57-member perturbed parameter ensemble of climate simulations of the HadCM3C Earth System model, for the baseline period 1961–1990, and the period 2070–2099 ("the 2080s". We consider where there are statistically significant increases or decreases in the proportion of time spent in drought in the 2080s compared to the baseline. Despite the large range of uncertainty in drought projections for many regions, projections for some regions have a clear signal, with uncertainty associated with the magnitude of change rather than direction. For instance, a significant increase in time spent in drought is generally projected for the Amazon, Central America and South Africa whilst projections for northern India consistently show significant decreases in time spent in drought. Whilst the patterns of changes in future drought were similar between scenarios, climate mitigation, represented by the RCP2.6 scenario, tended to reduce future changes in drought. In general, climate mitigation reduced the area over which there was a significant increase in drought but had little impact on the area over which there was a significant decrease in time spent in drought.

  14. Palmer Drought Severity Index

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — PDSI from the Dai dataset. The Palmer Drought Severity Index (PDSI) is devised by Palmer (1965) to represent the severity of dry and wet spells over the U.S. based...

  15. Trends in Drought Frequency. The Fate of DOC Export From British Peatlands

    Energy Technology Data Exchange (ETDEWEB)

    Worrall, F. [Department of Geological Sciences, Science Laboratories, South Road, Durham, DH1 3LE (United Kingdom); Burt, T.P. [Department of Geography, Science Laboratories, South Road, Durham, DH1 3LE (United Kingdom); Adamson, J.K. [Environmental Change Network, Centre for Ecology and Hydrology, Merlewood, Windermere Road, Grange over Sands, Cumbria, LA11 6JU (United Kingdom)

    2006-06-15

    There is increasing evidence that drought is leading to increased loss of dissolved organic carbon (DOC) from upland peats. Therefore, this study endeavours to understand the severity and frequency of the scale of drought responsible for driving the observed changes; and, by reconstructing climatic records, to understand whether such droughts are increasing in severity and frequency. The study suggests that there are two levels of drought severity important in the peatlands: a hydrological drought that causes hydrophobic effects in the upper peat profile lasting 3-4 years in duration, and a more severe biogeochemical drought that triggers new mechanisms of DOC production and decade-long effects. The study uses long term climate data from Central England and Northern England to reconstructs depth to water table for an upland peat catchment back to 1766 and shows that hydrological drought has a return period of 25 years and that biogeochemical drought has a return period of 15.5 years. Statistical modelling of the time series of annual droughts shows only weak evidence for an increasing frequency of severe droughts since 1766, but stronger evidence for the recent past. The return period of drought of sufficient severity to cause biogeochemical response is coming close to the length of effect such a drought would have, i.e. trends in drought frequency mean that peatlands may no longer be resilient to the impact of drought, with dire consequences for the storage of carbon in these environments.

  16. Drought vulnerability assesssment and mapping in Morocco

    Science.gov (United States)

    Imani, Yasmina; Lahlou, Ouiam; Bennasser Alaoui, Si; Naumann, Gustavo; Barbosa, Paulo; Vogt, Juergen

    2014-05-01

    Drought vulnerability assessment and mapping in Morocco Authors: Yasmina Imani 1, Ouiam Lahlou 1, Si Bennasser Alaoui 1 Paulo Barbosa 2, Jurgen Vogt 2, Gustavo Naumann 2 1: Institut Agronomique et Vétérinaire Hassan II (IAV Hassan II), Rabat Morocco. 2: European Commission, Joint Research Centre (JRC), Institute for Environment and Sustainability (IES), Ispra, Italy. In Morocco, nearly 50% of the population lives in rural areas. They are mostly small subsistent farmers whose production depends almost entirely on rainfall. They are therefore very sensitive to drought episodes that may dramatically affect their incomes. Although, as a consequence of the increasing frequency, length and severity of drought episodes in the late 90's, the Moroccan government decided, to move on from a crisis to a risk management approach, drought management remains in practice mainly reactive and often ineffective. The lack of effectiveness of public policy is in part a consequence of the poor understanding of drought vulnerability at the rural community level, which prevents the development of efficient mitigation actions and adaptation strategies, tailored to the needs and specificities of each rural community. Thus, the aim of this study is to assess and map drought vulnerability at the rural commune level in the Oum Er-Rbia basin which is a very heterogeneous basin, showing a big variability of climates, landscapes, cropping systems and social habits. Agricultural data collected from the provincial and local administrations of Agriculture and socio-economic data from the National Department of Statistics were used to compute a composite vulnerability index (DVI) integrating four different components: (i) the renewable natural capacity, (ii) the economic capacity, (iii) human and civic resources, and (iv) infrastructure and technology. The drought vulnerability maps that were derived from the computation of the DVI shows that except very specific areas, most of the Oum er Rbia

  17. Hydrological drought types in cold climates: quantitative analysis of causing factors and qualitative survey of impacts

    Directory of Open Access Journals (Sweden)

    A. F. Van Loon

    2015-04-01

    Full Text Available For drought management and prediction, knowledge of causing factors and socio-economic impacts of hydrological droughts is crucial. Propagation of meteorological conditions in the hydrological cycle results in different hydrological drought types that require separate analysis. In addition to the existing hydrological drought typology, we here define two new drought types related to snow and ice. A snowmelt drought is a deficiency in the snowmelt discharge peak in spring in snow-influenced basins and a glaciermelt drought is a deficiency in the glaciermelt discharge peak in summer in glacierised basins. In 21 catchments in Austria and Norway we studied the meteorological conditions in the seasons preceding and at the time of snowmelt and glaciermelt drought events. Snowmelt droughts in Norway were mainly controlled by below-average winter precipitation, while in Austria both temperature and precipitation played a role. For glaciermelt droughts, the effect of below-average summer air temperature was dominant, both in Austria and Norway. Subsequently, we investigated the impacts of temperature-related drought types (i.e. snowmelt and glaciermelt drought, but also cold and warm snow season drought and rain-to-snow-season drought. In historical archives and drought databases for the US and Europe many impacts were found that can be attributed to these temperature-related hydrological drought types, mainly in the agriculture and electricity production (hydropower sectors. However, drawing conclusions on the frequency of occurrence of different drought types from reported impacts is difficult, mainly because of reporting biases and the inevitably limited spatial and temporal scales of the information. Finally, this study shows that complete integration of quantitative analysis of causing factors and qualitative analysis of impacts of temperature-related droughts is not yet possible. Analysis of selected events, however, points out that it can be a

  18. Hydrological drought types in cold climates: quantitative analysis of causing factors and qualitative survey of impacts

    Science.gov (United States)

    Van Loon, A. F.; Ploum, S. W.; Parajka, J.; Fleig, A. K.; Garnier, E.; Laaha, G.; Van Lanen, H. A. J.

    2015-04-01

    For drought management and prediction, knowledge of causing factors and socio-economic impacts of hydrological droughts is crucial. Propagation of meteorological conditions in the hydrological cycle results in different hydrological drought types that require separate analysis. In addition to the existing hydrological drought typology, we here define two new drought types related to snow and ice. A snowmelt drought is a deficiency in the snowmelt discharge peak in spring in snow-influenced basins and a glaciermelt drought is a deficiency in the glaciermelt discharge peak in summer in glacierised basins. In 21 catchments in Austria and Norway we studied the meteorological conditions in the seasons preceding and at the time of snowmelt and glaciermelt drought events. Snowmelt droughts in Norway were mainly controlled by below-average winter precipitation, while in Austria both temperature and precipitation played a role. For glaciermelt droughts, the effect of below-average summer air temperature was dominant, both in Austria and Norway. Subsequently, we investigated the impacts of temperature-related drought types (i.e. snowmelt and glaciermelt drought, but also cold and warm snow season drought and rain-to-snow-season drought). In historical archives and drought databases for the US and Europe many impacts were found that can be attributed to these temperature-related hydrological drought types, mainly in the agriculture and electricity production (hydropower) sectors. However, drawing conclusions on the frequency of occurrence of different drought types from reported impacts is difficult, mainly because of reporting biases and the inevitably limited spatial and temporal scales of the information. Finally, this study shows that complete integration of quantitative analysis of causing factors and qualitative analysis of impacts of temperature-related droughts is not yet possible. Analysis of selected events, however, points out that it can be a promising research

  19. Reconfigurable multiport EPON repeater

    Science.gov (United States)

    Oishi, Masayuki; Inohara, Ryo; Agata, Akira; Horiuchi, Yukio

    2009-11-01

    An extended reach EPON repeater is one of the solutions to effectively expand FTTH service areas. In this paper, we propose a reconfigurable multi-port EPON repeater for effective accommodation of multiple ODNs with a single OLT line card. The proposed repeater, which has multi-ports in both OLT and ODN sides, consists of TRs, BTRs with the CDR function and a reconfigurable electrical matrix switch, can accommodate multiple ODNs to a single OLT line card by controlling the connection of the matrix switch. Although conventional EPON repeaters require full OLT line cards to accommodate subscribers from the initial installation stage, the proposed repeater can dramatically reduce the number of required line cards especially when the number of subscribers is less than a half of the maximum registerable users per OLT. Numerical calculation results show that the extended reach EPON system with the proposed EPON repeater can save 17.5% of the initial installation cost compared with a conventional repeater, and can be less expensive than conventional systems up to the maximum subscribers especially when the percentage of ODNs in lightly-populated areas is higher.

  20. Improvement of the drought indicators system in the Júcar River Basin, Spain.

    Science.gov (United States)

    Ortega-Gómez, Tatiana; Pérez-Martín, Miguel A; Estrela, Teodoro

    2017-08-11

    Droughts are one of the gravest natural threats currently existing in the world and their occurrence and intensity might be exacerbated in the coming years due to climate change. The severe impacts that droughts cause to inland water resources and to the associated socio-economic activities justify the continuous monitoring of the drought. The case study presented shows a practical application of a distributed drought monitoring system implemented in a real river basin district, the Júcar River Basin District (43,000km(2)), where drought periods of marked intensity have occurred historically and the climate ranges from humid in the north to semiarid in the south. Five drought indices have been applied: Standardised Precipitation Index (SPI) for meteorological drought; Palmer Drought Severity Index (PDSI) and a new soil moisture index (HI), for edaphic drought; Normalised Difference Vegetation Index (NDVI) for the vegetation activity; and Spanish Status Index (SI), for the operational drought. All indices are standardised to compare them. The relationship between the standardised operational drought index SI and the long-term meteorological indices, SPI-12 or SPI-24, show that in a medium size basin the concept of "prolonged drought" required by the European Commission under the Water Framework Directive could be defined by the use of accumulated precipitation indices. The number of months to be accumulated depends on the size of the basin and the water management system properties. In large basins, such as the Júcar river basin (22,000km(2)), there are significant deviations due to the spatial distribution of the drought. The use of a unique aggregated indicator could hide a significant drought in a specific area, or on the other hand show a non-real drought. Evolution of drought indices for each water management system must be accompanied by spatially distributed drought maps to better understand the drought status and its evolution. Copyright © 2017 Elsevier B

  1. Classification of Meteorological Drought

    Institute of Scientific and Technical Information of China (English)

    Zhang Qiang; Zou Xukai; Xiao Fengjin; Lu Houquan; Liu Haibo; Zhu Changhan; An Shunqing

    2011-01-01

    Background The national standard of the Classification of Meteorological Drought (GB/T 20481-2006) was developed by the National Climate Center in cooperation with Chinese Academy of Meteorological Sciences,National Meteorological Centre and Department of Forecasting and Disaster Mitigation under the China Meteorological Administration (CMA),and was formally released and implemented in November 2006.In 2008,this Standard won the second prize of the China Standard Innovation and Contribution Awards issued by SAC.Developed through independent innovation,it is the first national standard published to monitor meteorological drought disaster and the first standard in China and around the world specifying the classification of drought.Since its release in 2006,the national standard of Classification of Meteorological Drought has been used by CMA as the operational index to monitor and drought assess,and gradually used by provincial meteorological sureaus,and applied to the drought early warning release standard in the Methods of Release and Propagation of Meteorological Disaster Early Warning Signal.

  2. Recent advances in the dissection of drought-stress regulatory networks and strategies for development of drought-tolerant transgenic rice plants

    OpenAIRE

    Todaka, Daisuke; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

    2015-01-01

    Advances have been made in the development of drought-tolerant transgenic plants, including cereals. Rice, one of the most important cereals, is considered to be a critical target for improving drought tolerance, as present-day rice cultivation requires large quantities of water and as drought-tolerant rice plants should be able to grow in small amounts of water. Numerous transgenic rice plants showing enhanced drought tolerance have been developed to date. Such genetically engineered plants ...

  3. Trends and variability of droughts over the Indian monsoon region

    Directory of Open Access Journals (Sweden)

    Ganeshchandra Mallya

    2016-06-01

    Full Text Available Drought characteristics for the Indian monsoon region are analyzed using two different datasets and standard precipitation index (SPI, standardized precipitation-evapotranspiration index (SPEI, Gaussian mixture model-based drought index (GMM-DI, and hidden Markov model-based drought index (HMM-DI for the period 1901–2004. Drought trends and variability were analyzed for three epochs: 1901–1935, 1936–1971 and 1972–2004. Irrespective of the dataset and methodology used, the results indicate an increasing trend in drought severity and frequency during the recent decades (1972–2004. Droughts are becoming more regional and are showing a general shift to the agriculturally important coastal south-India, central Maharashtra, and Indo-Gangetic plains indicating higher food security and socioeconomic vulnerability in the region.

  4. Drought impacts on children's respiratory health in the Brazilian Amazon.

    Science.gov (United States)

    Smith, Lauren T; Aragão, Luiz E O C; Sabel, Clive E; Nakaya, Tomoki

    2014-01-16

    Drought conditions in Amazonia are associated with increased fire incidence, enhancing aerosol emissions with degradation in air quality. Quantifying the synergic influence of climate and human-driven environmental changes on human health is, therefore, critical for identifying climate change adaptation pathways for this vulnerable region. Here we show a significant increase (1.2%-267%) in hospitalisations for respiratory diseases in children under-five in municipalities highly exposed to drought. Aerosol was the primary driver of hospitalisations in drought affected municipalities during 2005, while human development conditions mitigated the impacts in 2010. Our results demonstrated that drought events deteriorated children's respiratory health particularly during 2005 when the drought was more geographically concentrated. This indicates that if governments act on curbing fire usage and effectively plan public health provision, as a climate change adaptation procedure, health quality would improve and public expenditure for treatment would decrease in the region during future drought events.

  5. Arbuscular mycorrhizal symbiosis induces strigolactone biosynthesis under drought and improves drought tolerance in lettuce and tomato.

    Science.gov (United States)

    Ruiz-Lozano, Juan Manuel; Aroca, Ricardo; Zamarreño, Ángel María; Molina, Sonia; Andreo-Jiménez, Beatriz; Porcel, Rosa; García-Mina, José María; Ruyter-Spira, Carolien; López-Ráez, Juan Antonio

    2016-02-01

    Arbuscular mycorrhizal (AM) symbiosis alleviates drought stress in plants. However, the intimate mechanisms involved, as well as its effect on the production of signalling molecules associated with the host plant-AM fungus interaction remains largely unknown. In the present work, the effects of drought on lettuce and tomato plant performance and hormone levels were investigated in non-AM and AM plants. Three different water regimes were applied, and their effects were analysed over time. AM plants showed an improved growth rate and efficiency of photosystem II than non-AM plants under drought from very early stages of plant colonization. The levels of the phytohormone abscisic acid, as well as the expression of the corresponding marker genes, were influenced by drought stress in non-AM and AM plants. The levels of strigolactones and the expression of corresponding marker genes were affected by both AM symbiosis and drought. The results suggest that AM symbiosis alleviates drought stress by altering the hormonal profiles and affecting plant physiology in the host plant. In addition, a correlation between AM root colonization, strigolactone levels and drought severity is shown, suggesting that under these unfavourable conditions, plants might increase strigolactone production in order to promote symbiosis establishment to cope with the stress.

  6. Modeling drought impact occurrence based on meteorological drought indices in Europe

    Science.gov (United States)

    Stagge, James H.; Kohn, Irene; Tallaksen, Lena M.; Stahl, Kerstin

    2015-11-01

    There is a vital need for research that links meteorological drought indices with drought impacts felt on the ground. Previously, this link has been estimated based on experience or defined based on very narrow impact measures. This study expands on earlier work by showing the feasibility of relating user-provided impact reports with meteorological drought indices, the Standardized Precipitation Index and the Standardized Precipitation-Evapotranspiration Index, through logistic regression, while controlling for seasonal and interannual effects. Analysis includes four impact types, spanning agriculture, energy and industry, public water supply, and freshwater ecosystem across five European countries. Statistically significant climate indices are retained as predictors using step-wise regression and used to compare the most relevant drought indices and accumulation periods across different impact types and regions. Agricultural impacts are explained by 2-12 month anomalies, though anomalies greater than 3 months are likely related to agricultural management practices. Energy and industrial impacts, typically related to hydropower and energy cooling water, respond slower (6-12 months). Public water supply and freshwater ecosystem impacts are explained by a more complex combination of short (1-3 month) and seasonal (6-12 month) anomalies. The resulting drought impact models have both good model fit (pseudo-R2 = 0.225-0.716) and predictive ability, highlighting the feasibility of using such models to predict drought impact likelihood based on meteorological drought indices.

  7. From meteorological to hydrological drought using standardised indicators

    Science.gov (United States)

    Barker, Lucy J.; Hannaford, Jamie; Chiverton, Andrew; Svensson, Cecilia

    2016-06-01

    Drought monitoring and early warning (M & EW) systems are a crucial component of drought preparedness. M & EW systems typically make use of drought indicators such as the Standardised Precipitation Index (SPI), but such indicators are not widely used in the UK. More generally, such tools have not been well developed for hydrological (i.e. streamflow) drought. To fill these research gaps, this paper characterises meteorological and hydrological droughts, and the propagation from one to the other, using the SPI and the related Standardised Streamflow Index (SSI), with the objective of improving understanding of the drought hazard in the UK. SPI and SSI time series were calculated for 121 near-natural catchments in the UK for accumulation periods of 1-24 months. From these time series, drought events were identified and for each event, the duration and severity were calculated. The relationship between meteorological and hydrological drought was examined by cross-correlating the 1-month SSI with various SPI accumulation periods. Finally, the influence of climate and catchment properties on the hydrological drought characteristics and propagation was investigated. Results showed that at short accumulation periods meteorological drought characteristics showed little spatial variability, whilst hydrological drought characteristics showed fewer but longer and more severe droughts in the south and east than in the north and west of the UK. Propagation characteristics showed a similar spatial pattern with catchments underlain by productive aquifers, mostly in the south and east, having longer SPI accumulation periods strongly correlated with the 1-month SSI. For catchments in the north and west of the UK, which typically have little catchment storage, standard-period average annual rainfall was strongly correlated with hydrological drought and propagation characteristics. However, in the south and east, catchment properties describing storage (such as base flow index, the

  8. Bivariate Drought Analysis Using Streamflow Reconstruction with Tree Ring Indices in the Sacramento Basin, California, USA

    Directory of Open Access Journals (Sweden)

    Jaewon Kwak

    2016-03-01

    Full Text Available Long-term streamflow data are vital for analysis of hydrological droughts. Using an artificial neural network (ANN model and nine tree-ring indices, this study reconstructed the annual streamflow of the Sacramento River for the period from 1560 to 1871. Using the reconstructed streamflow data, the copula method was used for bivariate drought analysis, deriving a hydrological drought return period plot for the Sacramento River basin. Results showed strong correlation among drought characteristics, and the drought with a 20-year return period (17.2 million acre-feet (MAF per year in the Sacramento River basin could be considered a critical level of drought for water shortages.

  9. Spatiotemporal analysis of droughts using self-calibrating Palmer's Drought Severity Index in the central region of South Africa

    Science.gov (United States)

    Edossa, Desalegn C.; Woyessa, Yali E.; Welderufael, Worku A.

    2016-11-01

    The loss of life and property from drought events has forced society to focus on the development of reliable early warning systems which may enable farmers and other stakeholders to correctly and timely adapt to the expected impacts of climatic hazard. However, a scientific approach to a reliable early warning system for a region requires, among others, characterisation of drought events in the region in terms of duration, magnitude, intensity and frequency using standard drought indices. Therefore, the objective of this study was to identify and characterise drought events in the Modder River basin, central region of South Africa, using a self-calibrated Palmer's Drought Severity Index (sc-PDSI). Attempts were also made to establish a relationship between meteorological and hydrological drought events in the region. During the period of analysis, the total number of drought episodes identified in the study area ranged between eight and sixteen. It was found that the most severe drought episodes occurred during the period 1992-1995 followed by the period 1982-1987. Results of analysis of seasonal drought events in one of the quaternary catchments (C52A) revealed that peak drought events during the three summer months (November, December and January) occurred in the area in 1993. However, in terms of event magnitude and intensity, the worst drought events were recorded during the period December 1982-July 1987, followed by the event that ensued during December 1989-September 1995. Results of analysis of decadal variation of drought events showed that the number of extreme and moderate drought events recorded in the catchment showed statistically significant increasing trends during the five decades at 5 % significance level. Moreover, spectral analysis of sc-PDSI time series in the region identified periodicities in the time series ranging from 6 years (C52E) to 16 years (C52K). In terms of the spatial extent of extreme drought events, the maximum areal coverage (91

  10. Different responses to the 2011 drought between native- and exotic-dominated experimental communities in Texas

    Science.gov (United States)

    Wilsey, B. J.; Polley, W.; Daneshgar, P. P.

    2014-12-01

    Global change includes invasion by non-native species, and invasion may affect ecosystem recovery from drought, especially when they cause species diversity declines. Here we test predictions in central Texas in a six-year experiment that compares mixtures of all exotic or all native species under two summer irrigation treatments (128 or 0 mm) that varies the amount of summer drought stress. A major drought (precipitation of 41% of normal) occurred in year 4 (2011), allowing a "natural experiment" test of how treatments affect drought resistance and recovery. Peak biomass was only 8% of pre-drought values in the drought year of 2011. Biomass resistance (drought/pre-drought biomass) and resilience (post-drought/pre-drought biomass) were similar among treatments. Native communities lost fewer species during the drought, and recovered more species after the drought than exotic communities. Over time, the responses in peak biomass to summer irrigation changed between native and exotic communities, with initially large responses in exotic communities in year 1 diminishing to non-significant responses by years 5 and 6. Native communities on the other hand, showed a small response to summer irrigation in year 1, but this response grew to become a large increase with irrigation by years 4-6. Reduced response to summer irrigation in exotic communities were associated with reduced species diversity and shifts in species composition towards C4 grasses. The differential effects of the drought indicate that non-native species will alter grassland community responses to drought events.

  11. Exploration of drought evolution using numerical simulations over the Xijiang (West River) basin in South China

    Science.gov (United States)

    Niu, Jun; Chen, Ji; Sun, Liqun

    2015-07-01

    The knowledge of drought evolution characteristics may aid the decision making process in mitigating drought impacts. This study uses a macro-scale hydrological model, Variable Infiltration Capacity (VIC) model, to simulate terrestrial hydrological processes over the Xijiang (West River) basin in South China. Three drought indices, namely standardized precipitation index (SPI), standardized runoff index (SRI), and soil moisture anomaly index (SMAI), are employed to examine the spatio-temporal and evolution features of drought events. SPI, SRI and SMAI represent meteorological drought, hydrological drought and agricultural drought, respectively. The results reveal that the drought severity depicted by SPI and SRI is similar with increasing timescales; SRI is close to that of SPI in the wet season for the Liu River basin as the high-frequency precipitation is conserved more by runoff; the time lags appear between SPI and SRI due to the delay response of runoff to precipitation variability for the You River basin. The case study in 2010 spring drought further shows that the spatio-temporal evolutions are modulated by the basin-scale topography. There is more consistency between meteorological and hydrological droughts for the fan-like basin with a converged river network. For the west area of the Xijiang basin with the high elevation, the hydrological drought severity is less than meteorological drought during the developing stage. The recovery of hydrological and agricultural droughts is slower than that of meteorological drought for basins with a longer mainstream.

  12. Observed and Projected Droughts Conditioned on Temperature Change

    Science.gov (United States)

    Chiang, F.; AghaKouchak, A.; Mazdiyasni, O.

    2016-12-01

    Droughts have had severe urban, agricultural and wildlife impacts in historical and recent years. In addition, during times of water scarcity, heat stress has been shown to produce compounding climatic and environmental effects. Understanding the overall conditions associated with drought intensities is important for mapping the anatomy of the climate in the changing world. For the study, we evaluated the relationship drought severity has exhibited with temperature shifts between observed periods and also between an ensemble of BCSD downscaled CMIP5 projected and historically modeled datasets. We compared temperatures during different categories of drought severity on a monthly scale, and mapped areas displaying an escalation of temperature with stricter definitions of drought. A historical shift of warmer temperatures in more severe droughts was observed most consistently in Southwestern and Eastern states between the later half of the 20th century and a reference period of the early half of the 20th century. Future projections from an ensemble of CMIP5 models also showed a shift to warmer temperatures during more intense drought events in similar states. Preliminary statistics show that in many areas future droughts will be warmer that the average projected climate. These observed and forecasted shifts in the heating intensity of severe drought events underscore the need to further research these patterns and relationships both spatially and temporally.

  13. Examining the Relationship between Drought Indices and Groundwater Levels

    Directory of Open Access Journals (Sweden)

    Navaratnam Leelaruban

    2017-01-01

    Full Text Available Thorough characterization of the response of finite water resources to climatic factors is essential for water monitoring and management. In this study, groundwater level data from U.S. Geological Survey Ground-Water Climate Response Network wells were used to analyze the relationship between selected drought indices and groundwater level fluctuation. The drought episodes included in this study were selected using climate division level drought indices. Indices included the Palmer Drought Severity Index, Palmer Hydrological Drought Index, and Standardized Precipitation Index (SPI-6, 9, 12, 24. Precipitation and the average temperature were also used. SPI-24 was found to correlate best with groundwater levels during drought. For 17 out of 32 wells, SPI-24 showed the best correlation amongst all of the indices. For 12 out of 32 wells, SPI-24 showed correlation coefficients of −0.6 or stronger; and for other wells, reasonably good correlation was demonstrated. The statistical significance of SPI-24 in predicting groundwater level was also tested. The correlation of average monthly groundwater levels with SPI-24 does not change much throughout the timeframe, for all of the studied wells. The duration of drought also had a significant correlation with the decline of groundwater levels. This study illustrates how drought indices can be used for a rapid assessment of drought impact on groundwater level.

  14. Ecological and meteorological drought monitoring in East Asia

    Science.gov (United States)

    Kim, J. B.; Um, M. J.; Kim, Y.; Chae, Y.

    2016-12-01

    This study aims to how well the ecological drought index can capture the drought status in the East Asia. We estimated the drought severe index (DSI), which uses the evapotranspiration, potential evapotranspiration and the normalized difference vegetation index (NDVI), suggested by Mu et al. (2013) to define the ecological drought. In addition, the meteorological drought index, which is standardized precipitation and evapotranspiration index (SPEI), are estimated and compared to the DSI. The satellite data by moderate resolution imaging spectroradiometer (MODIS) and advanced very-high-resolution radiometer (AVHRR) are used to analyze the DSI and the monthly precipitation and temperature data in the climate research unit (CRU) are applied to estimate the SPEI for 2000-2013 in the East Asia. We conducted the statistical analyses to investigate the drought characteristics of the ecological and meteorological drought indices (i.e. the DSI and SPEI, respectively) and then compared those characteristics drought indices depending on the drought status. We found the DSI did not well captured the drought status when the categories originally suggested by Mu et al. (2013) are applied to divide the drought status in the study area. Consequently, the modified categories for the DSI in this study is suggested and then applied to define the drought status. The modified categories in this study show the great improvement to capture the drought status in the East Asia even though the results cannot be acquired around Taklamakan desert due to the lack of the satellite data. These results illustrate the ecological drought index, such as the DSI, can be applied for the monitoring of the drought in the East Asia and then can give the detailed information of drought status because the satellite data have the relatively high spatial resolutions compared to the observations such as the CRU data. Reference Mu Q, Zhao M, Kimball JS, McDowell NG, Running SW (2013) A remotely sensed global

  15. Combined use of meteorological drought indices at multi-time scales for improving hydrological drought detection.

    Science.gov (United States)

    Zhu, Ye; Wang, Wen; Singh, Vijay P; Liu, Yi

    2016-11-15

    Prediction of hydrological drought in the absence of hydrological records is of great significance for water resources management and risk assessment. In this study, two meteorological drought indices, including standardized precipitation index (SPI) and standardized precipitation evapotranspiration index (SPEI) calculated at different time scales (1 to 12months), were analyzed for their capabilities in detecting hydrological droughts. The predictive skills of meteorological drought indices were assessed through correlation analysis, and two skill scores, i.e. probability of detection (POD) and false alarm rate (FAR). When used independently, indices of short time scales generally performed better than did those of long time scales. However, at least 31% of hydrological droughts were still missed in view of the peak POD score (0.69) of a single meteorological drought index. Considering the distinguished roles of different time scales in explaining hydrological droughts with disparate features, an optimization approach of blending SPI/SPEI at multiple time scales was proposed. To examine the robustness of the proposed method, data of 1964-1990 was used to establish the multiscalar index, then validate during 2000-2010. Results showed that POD exhibited a significant increase when more than two time scales were used, and the best performances were found when blending 8 time scales of SPI and 9 for SPEI, with the corresponding values of 0.82 and 0.85 for POD, 0.205 and 0.21 for FAR, in the calibration period, and even better performance in the validation period. These results far exceeded the performance of any single meteorological drought index. This suggests that when there is lack of streamflow measurements, blending climatic information of multiple time scales to jointly monitor hydrological droughts could be an alternative solution. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. A vantage from space can detect earlier drought onset: an approach using relative humidity.

    Science.gov (United States)

    Farahmand, Alireza; AghaKouchak, Amir; Teixeira, Joao

    2015-02-25

    Each year, droughts cause significant economic and agricultural losses across the world. The early warning and onset detection of drought is of particular importance for effective agriculture and water resource management. Previous studies show that the Standard Precipitation Index (SPI), a measure of precipitation deficit, detects drought onset earlier than other indicators. Here we show that satellite-based near surface air relative humidity data can further improve drought onset detection and early warning. This paper introduces the Standardized Relative Humidity Index (SRHI) based on the NASA Atmospheric Infrared Sounder (AIRS) observations. The results indicate that the SRHI typically detects the drought onset earlier than the SPI. While the AIRS mission was not originally designed for drought monitoring, we show that its relative humidity data offers a new and unique avenue for drought monitoring and early warning. We conclude that the early warning aspects of SRHI may have merit for integration into current drought monitoring systems.

  17. Improving Multi-Sensor Drought Monitoring, Prediction and Recovery Assessment Using Gravimetry Information

    Science.gov (United States)

    Aghakouchak, Amir; Tourian, Mohammad J.

    2015-04-01

    Development of reliable drought monitoring, prediction and recovery assessment tools are fundamental to water resources management. This presentation focuses on how gravimetry information can improve drought assessment. First, we provide an overview of the Global Integrated Drought Monitoring and Prediction System (GIDMaPS) which offers near real-time drought information using remote sensing observations and model simulations. Then, we present a framework for integration of satellite gravimetry information for improving drought prediction and recovery assessment. The input data include satellite-based and model-based precipitation, soil moisture estimates and equivalent water height. Previous studies show that drought assessment based on one single indicator may not be sufficient. For this reason, GIDMaPS provides drought information based on multiple drought indicators including Standardized Precipitation Index (SPI), Standardized Soil Moisture Index (SSI) and the Multivariate Standardized Drought Index (MSDI) which combines SPI and SSI probabilistically. MSDI incorporates the meteorological and agricultural drought conditions and provides composite multi-index drought information for overall characterization of droughts. GIDMaPS includes a seasonal prediction component based on a statistical persistence-based approach. The prediction component of GIDMaPS provides the empirical probability of drought for different severity levels. In this presentation we present a new component in which the drought prediction information based on SPI, SSI and MSDI are conditioned on equivalent water height obtained from the Gravity Recovery and Climate Experiment (GRACE). Using a Bayesian approach, GRACE information is used to evaluate persistence of drought. Finally, the deficit equivalent water height based on GRACE is used for assessing drought recovery. In this presentation, both monitoring and prediction components of GIDMaPS will be discussed, and the results from 2014

  18. Drought modes in West Africa and how well CORDEX RCMs simulate them

    Science.gov (United States)

    Diasso, Ulrich; Abiodun, Babatunde J.

    2015-12-01

    This study presents the spatial-temporal structure of droughts in West Africa and evaluates the capability of CORDEX regional climate models in simulating the droughts. The study characterize droughts with the standardized evapo-transpiration index (SPEI) computed using the monthly rainfall and temperature data from the Climatic Research Unit (CRU) and CORDEX models simulation datasets. To obtain the spatial-temporal structure of the droughts, we applied the principal component analysis on the observed and simulated SPEIs and retained the first four principal factors as the leading drought modes over West Africa. The relationship between the drought modes and atmospheric teleconnections was studied using wavelet coherence analysis, while the ability of the CORDEX models to simulate the drought modes was quantified with correlation analysis. The analysis of the relationship between drought modes and atmospheric teleconnections is based on SPEI from observation dataset (CRU). The study shows that about 60 % of spatial-temporal variability in SPEI over West Africa can be grouped into four drought modes. The first drought mode features drought over east Sahel, the second over west Sahel, the third over the Savanna, and the fourth over the Guinea coast. Each drought mode is linked to sea surface temperature anomalies (SSTAs) over tropical areas of Pacific, Atlantic, and Indian Oceans. Most CORDEX models reproduce at least two of the drought modes, but only two models (REMO and CNRM) reproduce all the four drought modes. REMO and WRF give the best simulation of the seasonal variation of the drought mode over the Sahel in March-May and June-August seasons, while CNRM gives the best simulation of seasonal variation in the drought pattern over the Savanna. Results of this study may guide in selecting appropriate CORDEX models for seasonal prediction of droughts and for downscaling projected impacts of global warming on droughts in West Africa.

  19. NAC transcription factor JUNGBRUNNEN1 enhances drought tolerance in tomato

    KAUST Repository

    Thirumalaikumar, Venkatesh P.

    2017-06-22

    Water deficit (drought stress) massively restricts plant growth and the yield of crops; reducing the deleterious effects of drought is therefore of high agricultural relevance. Drought triggers diverse cellular processes including the inhibition of photosynthesis, the accumulation of cell-damaging reactive oxygen species, and gene expression reprogramming, besides others. Transcription factors (TF) are central regulators of transcriptional reprogramming and expression of many TF genes is affected by drought, including members of the NAC family. Here, we identify the NAC factor JUNGBRUNNEN1 (JUB1) as a regulator of drought tolerance in tomato (Solanum lycopersicum). Expression of tomato JUB1 (SlJUB1) is enhanced by various abiotic stresses, including drought. Inhibiting SlJUB1 by virus-induced gene silencing drastically lowers drought tolerance concomitant with an increase in ion leakage, an elevation of hydrogen peroxide (H2 O2 ) levels, and a decrease of the expression of various drought-responsive genes. In contrast, overexpression of AtJUB1 from Arabidopsis thaliana increases drought tolerance in tomato, alongside with a higher relative leaf water content during drought and reduced H2 O2 levels. AtJUB1 was previously shown to stimulate expression of DREB2A, a TF involved in drought responses, and of the DELLA genes GAI and RGL1. We show here that SlJUB1 similarly controls the expression of the tomato orthologs SlDREB1, SlDREB2, and SlDELLA. Furthermore, AtJUB1 directly binds to the promoters of SlDREB1, SlDREB2 and SlDELLA in tomato. Our study highlights JUB1 as a transcriptional regulator of drought tolerance and suggests considerable conservation of the abiotic stress-related gene regulatory networks controlled by this NAC factor between Arabidopsis and tomato. This article is protected by copyright. All rights reserved.

  20. The European 2015 drought from a hydrological perspective

    Science.gov (United States)

    Laaha, Gregor; Gauster, Tobias; Tallaksen, Lena M.; Vidal, Jean-Philippe; Stahl, Kerstin; Prudhomme, Christel; Heudorfer, Benedikt; Vlnas, Radek; Ionita, Monica; Van Lanen, Henny A. J.; Adler, Mary-Jeanne; Caillouet, Laurie; Delus, Claire; Fendekova, Miriam; Gailliez, Sebastien; Hannaford, Jamie; Kingston, Daniel; Van Loon, Anne F.; Mediero, Luis; Osuch, Marzena; Romanowicz, Renata; Sauquet, Eric; Stagge, James H.; Wong, Wai K.

    2017-06-01

    In 2015 large parts of Europe were affected by drought. In this paper, we analyze the hydrological footprint (dynamic development over space and time) of the drought of 2015 in terms of both severity (magnitude) and spatial extent and compare it to the extreme drought of 2003. Analyses are based on a range of low flow and hydrological drought indices derived for about 800 streamflow records across Europe, collected in a community effort based on a common protocol. We compare the hydrological footprints of both events with the meteorological footprints, in order to learn from similarities and differences of both perspectives and to draw conclusions for drought management. The region affected by hydrological drought in 2015 differed somewhat from the drought of 2003, with its center located more towards eastern Europe. In terms of low flow magnitude, a region surrounding the Czech Republic was the most affected, with summer low flows that exhibited return intervals of 100 years and more. In terms of deficit volumes, the geographical center of the event was in southern Germany, where the drought lasted a particularly long time. A detailed spatial and temporal assessment of the 2015 event showed that the particular behavior in these regions was partly a result of diverging wetness preconditions in the studied catchments. Extreme droughts emerged where preconditions were particularly dry. In regions with wet preconditions, low flow events developed later and tended to be less severe. For both the 2003 and 2015 events, the onset of the hydrological drought was well correlated with the lowest flow recorded during the event (low flow magnitude), pointing towards a potential for early warning of the severity of streamflow drought. Time series of monthly drought indices (both streamflow- and climate-based indices) showed that meteorological and hydrological events developed differently in space and time, both in terms of extent and severity (magnitude). These results

  1. The European 2015 drought from a hydrological perspective

    Directory of Open Access Journals (Sweden)

    G. Laaha

    2017-06-01

    Full Text Available In 2015 large parts of Europe were affected by drought. In this paper, we analyze the hydrological footprint (dynamic development over space and time of the drought of 2015 in terms of both severity (magnitude and spatial extent and compare it to the extreme drought of 2003. Analyses are based on a range of low flow and hydrological drought indices derived for about 800 streamflow records across Europe, collected in a community effort based on a common protocol. We compare the hydrological footprints of both events with the meteorological footprints, in order to learn from similarities and differences of both perspectives and to draw conclusions for drought management. The region affected by hydrological drought in 2015 differed somewhat from the drought of 2003, with its center located more towards eastern Europe. In terms of low flow magnitude, a region surrounding the Czech Republic was the most affected, with summer low flows that exhibited return intervals of 100 years and more. In terms of deficit volumes, the geographical center of the event was in southern Germany, where the drought lasted a particularly long time. A detailed spatial and temporal assessment of the 2015 event showed that the particular behavior in these regions was partly a result of diverging wetness preconditions in the studied catchments. Extreme droughts emerged where preconditions were particularly dry. In regions with wet preconditions, low flow events developed later and tended to be less severe. For both the 2003 and 2015 events, the onset of the hydrological drought was well correlated with the lowest flow recorded during the event (low flow magnitude, pointing towards a potential for early warning of the severity of streamflow drought. Time series of monthly drought indices (both streamflow- and climate-based indices showed that meteorological and hydrological events developed differently in space and time, both in terms of extent and severity

  2. Show Time

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正> Story: Show Time!The whole class presents the story"Under the Sea".Everyone is so excited and happy.Both Leo and Kathy show their parentsthe characters of the play."Who’s he?"asks Kathy’s mom."He’s the prince."Kathy replies."Who’s she?"asks Leo’s dad."She’s the queen."Leo replieswith a smile.

  3. Snobbish Show

    Institute of Scientific and Technical Information of China (English)

    YIN PUMIN

    2010-01-01

    @@ The State Administration of Radio,Film and Television (SARFT),China's media watchdog,issued a new set of mles on June 9 that strictly regulate TV match-making shows,which have been sweeping the country's primetime programming. "Improper social and love values such as money worship should not be presented in these shows.Humiliation,verbal attacks and sex-implied vulgar content are not allowed" the new roles said.

  4. Single and repeated moderate consumption of native or dealcoholized red wine show different effects on antioxidant parameters in blood and DNA strand breaks in peripheral leukocytes in healthy volunteers: a randomized controlled trial [ISRCTN68505294

    Directory of Open Access Journals (Sweden)

    Spengler Ulrich

    2005-11-01

    Full Text Available Abstract Background Red wine (RW is rich in antioxidant polyphenols that might protect from oxidative stress related diseases, such as cardiovascular disease and cancer. Antioxidant effects after single ingestion of RW or dealcoholized RW (DRW have been observed in several studies, but results after regular consumption are contradictory. Thus, we examined if single or repeated consumption of moderate amounts of RW or DRW exert antioxidant activity in vivo. Methods Total phenolic content and concentration of other antioxidants in plasma/serum, total antioxidant capacity (TEAC in plasma as well as DNA strand breaks in peripheral leukocytes were measured in healthy non-smokers A before, 90 and 360 min after ingestion of one glass of RW, DRW or water; B before and after consumption of one glass of RW or DRW daily for 6 weeks. DNA strand breaks (SB were determined by single cell gel electrophoresis (Comet Assay in untreated cells and after induction of oxidative stress ex vivo with H2O2 (300 μM, 20 min. Results Both RW and DRW transiently increased total phenolic content in plasma after single consumption, but only RW lead to a sustained increase if consumed regularly. Plasma antioxidant capacity was not affected by single or regular consumption of RW or DRW. Effects of RW and DRW on DNA SB were conflicting. DNA strand breaks in untreated cells increased after a single dose of RW and DRW, whereas H2O2 induced SB were reduced after DRW. In contrast, regular RW consumption reduced SB in untreated cells but did not affect H2O2 induced SB. Conclusion The results suggest that consumption of both RW and DRW leads to an accumulation of phenolic compounds in plasma without increasing plasma antioxidant capacity. Red wine and DRW seem to affect the occurrence of DNA strand breaks, but this cannot be referred to antioxidant effects.

  5. Projections of agricultural droughts in the Southeast Asia

    Science.gov (United States)

    Mishra, V.

    2014-12-01

    Southeast Asia is one of the most populated regions in the world, which falls among the food insecure regions. Droughts during the monsoon season hamper crop growth and food production. During the last few decades, rainfall in the monsoon season has been erratic leading to some of the most wide spread droughts in the region. Severity, areal extents, and frequency of droughts are analyzed using the observed data for the period of 1951-2007. Results indicate that frequency of severe drought increased in the Southeast Asia during the recent decades (1980-2007). To assess the variability of hydrologic and agricultural drought in the region, runoff and soil moisture were simulated using the Variable Infiltration Capacity (VIC) model. The model simulated drought variability was compared with drought simulated by the CMIP5 models during the historic period (1951-2005). Most of the CMIP5 models show increased frequency of severe agricultural droughts in the region under the projected future climate. Increased agricultural droughts in the Southeast Asia may put enormous pressure on the efforts towards achieving food security in the region.

  6. Anthropogenic warming has caused hot droughts more frequently in China

    Science.gov (United States)

    Chen, Huopo; Sun, Jianqi

    2017-01-01

    Historical records have indicated an increase in high-impact drought occurrences across China during recent decades, but whether this increase is due to natural variability or anthropogenic change remains unclear. Thus, the shift toward dry conditions and their associated attributions across China are discussed in this study, primarily regarding the standardized precipitation evapotranspiration index (SPEI). The results show that drought occurrences across China increased consistently during 1951-2014, especially during the recent twenty years. Most of the increased drought events happened under warm-dry conditions that coincided with relatively high temperature anomalies but without large anomalies in annual precipitation, implying an increase in hot drought events across China. Further analysis revealed that the change in drought occurrences were mainly due to the combined activity of external natural forcings and anthropogenic changes across China. However, external natural forcings were mainly responsible for the variability of droughts and anthropogenic influences for their increasing trends, suggesting that anthropogenic warming has increased hot drought occurrences, associated risks and impacts across China. With continued warming in the future, the impact of anthropogenic warming on the increased hot drought events will be further amplified. The probability of warm years is projected to significantly increase, and the occurrence probability of hot drought events (SPEI precipitation is projected to increase across China in the future.

  7. Stress Memory and the Inevitable Effects of Drought: A Physiological Perspective.

    Science.gov (United States)

    Fleta-Soriano, Eva; Munné-Bosch, Sergi

    2016-01-01

    Plants grow and develop by adjusting their physiology to changes in their environment. Changes in the abiotic environment occur over years, seasons, and days, but also over minutes and even seconds. In this ever-changing environment, plants may adjust their structure and function rapidly to optimize growth and reproduction. Plant responses to reiterated drought (i.e., repeated cycles of drought) differ from those to single incidences of drought; in fact, in nature, plants are usually exposed to repeated cycles of drought that differ in duration and intensity. Nowadays, there is increased interest in better understanding mechanisms of plant response to reiterated drought due, at least in part, to the discovery of epigenomic changes that trigger drought stress memory in plants. Beyond epigenomic changes, there are, however, other aspects that should be considered in the study of plant responses to reiterated drought: from changes in other "omics" approaches (transcriptomics, proteomics, and metabolomics), to changes in plant structure; all of which may help us to better understand plant stress memory and its underlying mechanisms. Here, we present an example in which reiterated drought affects the pigment composition of leaves in the ornamental plant Silene dioica and discuss the importance of structural changes (in this case in the photosynthetic apparatus) for the plant response to reiterated drought; they represent a stress imprint that can affect plant response to subsequent stress episodes. Emphasis is placed on the importance of considering structural changes, in addition to physiological adjustments at the "omics" level, to understand stress memory in plants better.

  8. Probabilistic prediction of hydrologic drought using a conditional probability approach based on the meta-Gaussian model

    Science.gov (United States)

    Hao, Zengchao; Hao, Fanghua; Singh, Vijay P.; Sun, Alexander Y.; Xia, Youlong

    2016-11-01

    Prediction of drought plays an important role in drought preparedness and mitigation, especially because of large impacts of drought and increasing demand for water resources. An important aspect for improving drought prediction skills is the identification of drought predictability sources. In general, a drought originates from precipitation deficit and thus the antecedent meteorological drought may provide predictive information for other types of drought. In this study, a hydrological drought (represented by Standardized Runoff Index (SRI)) prediction method is proposed based on the meta-Gaussian model taking into account the persistence and its prior meteorological drought condition (represented by Standardized Precipitation Index (SPI)). Considering the inherent nature of standardized drought indices, the meta-Gaussian model arises as a suitable model for constructing the joint distribution of multiple drought indices. Accordingly, the conditional distribution of hydrological drought can be derived analytically, which enables the probabilistic prediction of hydrological drought in the target period and uncertainty quantifications. Based on monthly precipitation and surface runoff of climate divisions of Texas, U.S., 1-month and 2-month lead predictions of hydrological drought are illustrated and compared to the prediction from Ensemble Streamflow Prediction (ESP). Results, based on 10 climate divisions in Texas, show that the proposed meta-Gaussian model provides useful drought prediction information with performance depending on regions and seasons.

  9. The European 2015 drought from a groundwater perspective

    Science.gov (United States)

    Van Loon, Anne; Kumar, Rohini; Mishra, Vimal

    2017-04-01

    averaged SGI above the 50th percentile. This is because slowly responding wells still were above average from the wet year of 2002-2003, which experienced severe flooding in central Europe. GRACE-TWS does show that both 2003 and 2015 were relatively dry, but the difference between Germany and the Netherlands in 2015 and the spatially-variable groundwater drought pattern in 2003 were not captured. This could be associated to the coarse spatial scale of GRACE. The simulated groundwater anomalies based on GRACE-TWS deviated considerably from the GRACE-TWS signal and from observed groundwater anomalies. These are therefore not suitable for use in real-time groundwater drought monitoring in our case study regions. Our study shows that the relationship between meteorological drought and groundwater drought can be used to quantify groundwater drought and that the 2015 groundwater drought in southern Germany was more severe than the 2003 drought, because of preconditions in slowly responding groundwater wells. For sustainable groundwater drought management strategies the use of groundwater level monitoring is needed to study the spatial variability of local groundwater drought, which mostly coincides with drought impacts.

  10. From meteorological to hydrological drought using standardised indicators

    Directory of Open Access Journals (Sweden)

    L. J. Barker

    2015-12-01

    Full Text Available Drought monitoring and early warning (M&EW systems are a crucial component of drought preparedness. M&EW systems typically make use of drought indicators such as the Standardised Precipitation Index (SPI, but such indicators are not widely used in the UK. More generally, such tools have not been well developed for hydrological (i.e. streamflow drought. To fill these research gaps, this paper characterises meteorological and hydrological droughts, and the propagation from one to the other using the SPI and the related Standardised Streamflow Index (SSI, with the objective of improving understanding of the drought hazard in the UK. SPI and SSI time series were calculated for 121 near-natural catchments in the UK for accumulation periods of 1–24 months. From these time series, drought events were identified and for each event, the duration and severity was calculated. The relationship between meteorological and hydrological drought was examined by cross-correlating the one month SSI with various SPI accumulation periods. Finally, the influence of climate and catchment properties on the drought characteristics and propagation were investigated. Results showed that at short accumulation periods meteorological drought characteristics showed little spatial variability, whilst hydrological drought characteristics showed fewer but longer and more severe droughts in the south and east than in the north and west of the UK. Propagation characteristics showed a similar spatial pattern with catchments underlain by productive aquifers, mostly in the south and east, having longer SPI accumulation periods strongly correlated with the one-month SSI. For catchments in the north and west of the UK, which typically have little catchment storage, standard-period annual average rainfall was strongly correlated to drought and propagation characteristics. However, in the south and east, catchment properties describing storage, such as base flow index, percentage of

  11. Quantifying drylands' drought resistance and recovery: the importance of drought intensity, dominant life history and grazing regime.

    Science.gov (United States)

    Ruppert, Jan C; Harmoney, Keith; Henkin, Zalmen; Snyman, Hennie A; Sternberg, Marcelo; Willms, Walter; Linstädter, Anja

    2015-03-01

    Projected global change will increase the level of land-use and environmental stressors such as drought and grazing, particularly in drylands. Still, combined effects of drought and grazing on plant production are poorly understood, thus hampering adequate projections and development of mitigation strategies. We used a large, cross-continental database consisting of 174 long-term datasets from >30 dryland regions to quantify ecosystem responses to drought and grazing with the ultimate goal to increase functional understanding in these responses. Two key aspects of ecosystem stability, resistance to and recovery after a drought, were evaluated based on standardized and normalized aboveground net primary production (ANPP) data. Drought intensity was quantified using the standardized precipitation index. We tested effects of drought intensity, grazing regime (grazed, ungrazed), biome (grassland, shrubland, savanna) or dominant life history (annual, perennial) of the herbaceous layer to assess the relative importance of these factors for ecosystem stability, and to identify predictable relationships between drought intensity and ecosystem resistance and recovery. We found that both components of ecosystem stability were better explained by dominant herbaceous life history than by biome. Increasing drought intensity (quasi-) linearly reduced ecosystem resistance. Even though annual and perennial systems showed the same response rate to increasing drought intensity, they differed in their general magnitude of resistance, with annual systems being ca. 27% less resistant. In contrast, systems with an herbaceous layer dominated by annuals had substantially higher postdrought recovery, particularly when grazed. Combined effects of drought and grazing were not merely additive but modulated by dominant life history of the herbaceous layer. To the best of our knowledge, our study established the first predictive, cross-continental model between drought intensity and drought

  12. Quantitative trait loci associated with drought tolerance in brachypodium distachyon

    Science.gov (United States)

    The temperate wild grass Brachypodium distachyon (Brachypodium) serves as model system for studying turf and forage grasses. Brachypodium collections show diverse responses to drought stress, but little is known about the genetic mechanisms of drought tolerance of this species. The objective of this...

  13. Global trends in future hydrological drought

    Science.gov (United States)

    Van Lanen, H.; Wanders, N.; Wada, Y.

    2013-12-01

    Climate change very likely impacts future hydrological drought characteristics worldwide (i.e. duration and intensity of drought in runoff). However, the magnitude and sign of the change is largely unknown. In this study we quantify impact of climate change on future low flows and hydrological droughts characteristics on a global scale. The global hydrological and water resources model PCR-GLOBWB was used to simulate future river runoff at 0.5 degree globally on a daily basis. The newly available CMIP5 climate projections were obtained through the Inter-Sectoral Impact Model Intercomparison Project (ISI-MIP). The model was forced with the daily transient climate fields taken from five GCMs and four underlying emission scenarios (here accounted for by using four Representative Concentration Pathways or RCPs). The monthly Q80 (20 percentile lowest flow) was used to evaluate the changes in low flows and as the threshold level for the hydrological drought characterisation. The monthly threshold was smoothed to allow for drought calculations on a daily basis. The thresholds in the future remained transient and were calculated over the climatology of the last 30 year period to reflect the adaptation of society to new conditions. Trends in the thresholds and drought characteristics were analysed over the period 2000-2099. Results for most GCMs and all RCPs showed that Q80 discharge (low flow metric) indicates a significant negative trend in large parts of South America, Central Africa, the Mediterranean and South East Asia. Under the higher greenhouse gas emission scenarios of RCP6.0 and RCP8.5, the USA and Central and South Europe were also projected to have drier conditions. For all future projections Russia and Canada were expected to get wetter during the 21st century. Under RCP6.0 and RCP8.5 scenarios, the results generally showed the strongest negative changes in future low flow. The results simulated with most GCMs agree well over many parts of the world, however

  14. Exploring the link between drought indicators and impacts

    Science.gov (United States)

    Bachmair, S.; Kohn, I.; Stahl, K.

    2015-06-01

    region specific to some degree. Concerning "thresholds" for drought impact onset, i.e. indicator values concurrent with past impact onsets, we found that no single "best" threshold value can be identified but impacts occur within a range of indicator values. Nevertheless, the median of the threshold distributions showed differences between northern/northeastern versus southern/southwestern federal states, and among drought events. While the findings strongly depend on data and may change with a growing number of EDII entries in the future, this study clearly demonstrates the feasibility of evaluating hydro-meteorologic variables with text-based impact reports and highlights the value of impact reporting as a tool for monitoring drought conditions.

  15. EROBATIC SHOW

    Institute of Scientific and Technical Information of China (English)

    2016-01-01

    Visitors look at plane models of the Commercial Aircraft Corp. of China, developer of the count,s first homegrown large passenger jet C919, during the Singapore Airshow on February 16. The biennial event is the largest airshow in Asia and one of the most important aviation and defense shows worldwide. A number of Chinese companies took part in the event during which Okay Airways, the first privately owned aidine in China, signed a deal to acquire 12 Boeing 737 jets.

  16. A new method to select the drought resistance azuki bean germplasm

    Institute of Scientific and Technical Information of China (English)

    Chen Xin; Peerasak Srinives

    2006-01-01

    120 azuki bean germplasms from different regions of China were selected for drought-resistance. Results showed that there is a significant positive correlation between drought-resistance and photooxidation-resistance. So, the detecting technique for photooxidation-resistance should be suggested as a reference method to select the drought-resistance germplasms in azuki bean.

  17. Introduction 'Governance for Drought Resilience'

    NARCIS (Netherlands)

    Bressers, Nanny; Bressers, Hans; Larrue, Corinne; Bressers, Hans; Bressers, Nanny; Larrue, Corinne

    2016-01-01

    This book is about governance for drought resilience. But that simple sentence alone might rouse several questions. Because what do we mean with drought, and how does that relate to water scarcity? And what do we mean with resilience, and why is resilience needed for tackling drought? And how does g

  18. Introduction 'Governance for Drought Resilience'

    NARCIS (Netherlands)

    Bressers, Nanny; Bressers, Johannes T.A.; Larrue, Corinne; Bressers, Hans; Bressers, Nanny; Larrue, Corinne

    2016-01-01

    This book is about governance for drought resilience. But that simple sentence alone might rouse several questions. Because what do we mean with drought, and how does that relate to water scarcity? And what do we mean with resilience, and why is resilience needed for tackling drought? And how does

  19. Drought impact functions as intermediate step towards drought damage assessment

    Science.gov (United States)

    Bachmair, Sophie; Svensson, Cecilia; Prosdocimi, Ilaria; Hannaford, Jamie; Helm Smith, Kelly; Svoboda, Mark; Stahl, Kerstin

    2016-04-01

    While damage or vulnerability functions for floods and seismic hazards have gained considerable attention, there is comparably little knowledge on drought damage or loss. On the one hand this is due to the complexity of the drought hazard affecting different domains of the hydrological cycle and different sectors of human activity. Hence, a single hazard indicator is likely not able to fully capture this multifaceted hazard. On the other hand, drought impacts are often non-structural and hard to quantify or monetize. Examples are impaired navigability of streams, restrictions on domestic water use, reduced hydropower production, reduced tree growth, and irreversible deterioration/loss of wetlands. Apart from reduced crop yield, data about drought damage or loss with adequate spatial and temporal resolution is scarce, making the development of drought damage functions difficult. As an intermediate step towards drought damage functions we exploit text-based reports on drought impacts from the European Drought Impact report Inventory and the US Drought Impact Reporter to derive surrogate information for drought damage or loss. First, text-based information on drought impacts is converted into timeseries of absence versus presence of impacts, or number of impact occurrences. Second, meaningful hydro-meteorological indicators characterizing drought intensity are identified. Third, different statistical models are tested as link functions relating drought hazard indicators with drought impacts: 1) logistic regression for drought impacts coded as binary response variable; and 2) mixture/hurdle models (zero-inflated/zero-altered negative binomial regression) and an ensemble regression tree approach for modeling the number of drought impact occurrences. Testing the predictability of (number of) drought impact occurrences based on cross-validation revealed a good agreement between observed and modeled (number of) impacts for regions at the scale of federal states or

  20. A multiscalar Palmer drought severity index

    Science.gov (United States)

    Liu, Yi; Zhu, Ye; Ren, Liliang; Singh, Vijay P.; Yang, Xiaoli; Yuan, Fei

    2017-07-01

    The limitation of the fixed time scale in the Palmer drought severity index (PDSI) family has long been criticized in drought literatures. By modifying the algorithm of duration factors estimation of the self-calibrating PDSI (SC-PDSI), this paper proposed a new approach that could extend the time scale in a wide range. The properties of these newly derived SC-PDSI variants (denoted as SC-PDSIx) at short, medium, and long time scales, respectively, were evaluated through comparisons with the multiscalar standardized precipitation evapotranspiration index (SPEI) over 134 meteorological sites in China. Results show that new SC-PDSIx generally inherits the advantages of original SC-PDSI with a rather stable behavior in aspects of drought frequency and other statistical characteristics. Besides, the spatiotemporal pattern of the 2011 drought reflected by matched SC-PDSIx and SPEI is very similar, indicating that the multiscalar SC-PDSI could be a useful alternative to monitor droughts at different time scales.

  1. Diagnosing Drought in a Changing Climate

    Science.gov (United States)

    Swann, A. L. S.; Hoffman, F. M.; Koven, C. D.; Randerson, J. T.

    2015-12-01

    Predictions of future climate impacts such as drought rely heavily on metrics based on changes in rainfall and changes in the demand for water from the atmosphere. However, the underlying driver of climate change is the increasing concentration of atmospheric carbon dioxide (CO2), which simultaneously increases temperature globally and modifies the water needs of plants. Although the influence of CO2 on plant stomatal conductance and transpiration is well established, the relative impact of this physiology on different drought metrics has not been rigorously assessed. We find that predictions of increasing drought stress derived using atmospheric demand metrics in many regions (including potential evapotraspiration and Palmer Drought Stress Index) correspond to places where Earth system models show stable or increasing water availability on land when assessed using the difference between precipitation and evapotranspiration. Approximately 70% of the increase in global water availability is a direct result of the effect of CO2 reducing plant water needs. Current models predict a decoupling of water flux and carbon flux, which require revisions to how aridity is measured and drought is calculated under changing CO2.

  2. RD26 mediates crosstalk between drought and brassinosteroid signalling pathways

    Science.gov (United States)

    Ye, Huaxun; Liu, Sanzhen; Tang, Buyun; Chen, Jiani; Xie, Zhouli; Nolan, Trevor M.; Jiang, Hao; Guo, Hongqing; Lin, Hung-Ying; Li, Lei; Wang, Yanqun; Tong, Hongning; Zhang, Mingcai; Chu, Chengcai; Li, Zhaohu; Aluru, Maneesha; Aluru, Srinivas; Schnable, Patrick S.; Yin, Yanhai

    2017-01-01

    Brassinosteroids (BRs) regulate plant growth and stress responses via the BES1/BZR1 family of transcription factors, which regulate the expression of thousands of downstream genes. BRs are involved in the response to drought, however the mechanistic understanding of interactions between BR signalling and drought response remains to be established. Here we show that transcription factor RD26 mediates crosstalk between drought and BR signalling. When overexpressed, BES1 target gene RD26 can inhibit BR-regulated growth. Global gene expression studies suggest that RD26 can act antagonistically to BR to regulate the expression of a subset of BES1-regulated genes, thereby inhibiting BR function. We show that RD26 can interact with BES1 protein and antagonize BES1 transcriptional activity on BR-regulated genes and that BR signalling can also repress expression of RD26 and its homologues and inhibit drought responses. Our results thus reveal a mechanism coordinating plant growth and drought tolerance. PMID:28233777

  3. Estimating drought risk across Europe from reported drought impacts, drought indices, and vulnerability factors

    Science.gov (United States)

    Blauhut, Veit; Stahl, Kerstin; Stagge, James Howard; Tallaksen, Lena M.; De Stefano, Lucia; Vogt, Jürgen

    2016-07-01

    Drought is one of the most costly natural hazards in Europe. Due to its complexity, drought risk, meant as the combination of the natural hazard and societal vulnerability, is difficult to define and challenging to detect and predict, as the impacts of drought are very diverse, covering the breadth of socioeconomic and environmental systems. Pan-European maps of drought risk could inform the elaboration of guidelines and policies to address its documented severity and impact across borders. This work tests the capability of commonly applied drought indices and vulnerability factors to predict annual drought impact occurrence for different sectors and macro regions in Europe and combines information on past drought impacts, drought indices, and vulnerability factors into estimates of drought risk at the pan-European scale. This hybrid approach bridges the gap between traditional vulnerability assessment and probabilistic impact prediction in a statistical modelling framework. Multivariable logistic regression was applied to predict the likelihood of impact occurrence on an annual basis for particular impact categories and European macro regions. The results indicate sector- and macro-region-specific sensitivities of drought indices, with the Standardized Precipitation Evapotranspiration Index (SPEI) for a 12-month accumulation period as the overall best hazard predictor. Vulnerability factors have only limited ability to predict drought impacts as single predictors, with information about land use and water resources being the best vulnerability-based predictors. The application of the hybrid approach revealed strong regional and sector-specific differences in drought risk across Europe. The majority of the best predictor combinations rely on a combination of SPEI for shorter and longer accumulation periods, and a combination of information on land use and water resources. The added value of integrating regional vulnerability information with drought risk prediction

  4. Monthly hydrometeorological ensemble prediction of streamflow droughts and corresponding drought indices

    Directory of Open Access Journals (Sweden)

    F. Fundel

    2013-01-01

    Full Text Available Streamflow droughts, characterized by low runoff as consequence of a drought event, affect numerous aspects of life. Economic sectors that are impacted by low streamflow are, e.g., power production, agriculture, tourism, water quality management and shipping. Those sectors could potentially benefit from forecasts of streamflow drought events, even of short events on the monthly time scales or below. Numerical hydrometeorological models have increasingly been used to forecast low streamflow and have become the focus of recent research. Here, we consider daily ensemble runoff forecasts for the river Thur, which has its source in the Swiss Alps. We focus on the evaluation of low streamflow and of the derived indices as duration, severity and magnitude, characterizing streamflow droughts up to a lead time of one month.

    The ECMWF VarEPS 5-member ensemble reforecast, which covers 18 yr, is used as forcing for the hydrological model PREVAH. A thorough verification reveals that, compared to probabilistic peak-flow forecasts, which show skill up to a lead time of two weeks, forecasts of streamflow droughts are skilful over the entire forecast range of one month. For forecasts at the lower end of the runoff regime, the quality of the initial state seems to be crucial to achieve a good forecast quality in the longer range. It is shown that the states used in this study to initialize forecasts satisfy this requirement. The produced forecasts of streamflow drought indices, derived from the ensemble forecasts, could be beneficially included in a decision-making process. This is valid for probabilistic forecasts of streamflow drought events falling below a daily varying threshold, based on a quantile derived from a runoff climatology. Although the forecasts have a tendency to overpredict streamflow droughts, it is shown that the relative economic value of the ensemble forecasts reaches up to 60%, in case a forecast user is able to take preventive

  5. Monthly hydrometeorological ensemble prediction of streamflow droughts and corresponding drought indices

    Science.gov (United States)

    Fundel, F.; Jörg-Hess, S.; Zappa, M.

    2013-01-01

    Streamflow droughts, characterized by low runoff as consequence of a drought event, affect numerous aspects of life. Economic sectors that are impacted by low streamflow are, e.g., power production, agriculture, tourism, water quality management and shipping. Those sectors could potentially benefit from forecasts of streamflow drought events, even of short events on the monthly time scales or below. Numerical hydrometeorological models have increasingly been used to forecast low streamflow and have become the focus of recent research. Here, we consider daily ensemble runoff forecasts for the river Thur, which has its source in the Swiss Alps. We focus on the evaluation of low streamflow and of the derived indices as duration, severity and magnitude, characterizing streamflow droughts up to a lead time of one month. The ECMWF VarEPS 5-member ensemble reforecast, which covers 18 yr, is used as forcing for the hydrological model PREVAH. A thorough verification reveals that, compared to probabilistic peak-flow forecasts, which show skill up to a lead time of two weeks, forecasts of streamflow droughts are skilful over the entire forecast range of one month. For forecasts at the lower end of the runoff regime, the quality of the initial state seems to be crucial to achieve a good forecast quality in the longer range. It is shown that the states used in this study to initialize forecasts satisfy this requirement. The produced forecasts of streamflow drought indices, derived from the ensemble forecasts, could be beneficially included in a decision-making process. This is valid for probabilistic forecasts of streamflow drought events falling below a daily varying threshold, based on a quantile derived from a runoff climatology. Although the forecasts have a tendency to overpredict streamflow droughts, it is shown that the relative economic value of the ensemble forecasts reaches up to 60%, in case a forecast user is able to take preventive action based on the forecast.

  6. Extreme Historical Droughts in the South-Eastern Alps - Analyses Based on Standardised Precipitation Index

    Directory of Open Access Journals (Sweden)

    Brenčič Mihael

    2016-10-01

    Full Text Available Droughts are natural phenomena affecting the environment and human activities. There are various drought definitions and quantitative indices; among them is the Standardised Precipitation Index (SPI. In the drought investigations, historical events are poorly characterised and little data are available. To decipher past drought appearances in the southeastern Alps with a focus on Slovenia, precipitation data from HISTALP data repository were taken to identify extreme drought events (SPI ≤ -2.00 from the second half of the 19th century to the present day. Several long-term extreme drought crises were identified in the region (between the years 1888 and 1896; after World War I, during and after World War II. After 1968, drought patterns detected with SPI changed: shorter, extreme droughts with different time patterns appeared. SPI indices of different time spans showed correlated structures in space and between each other, indicating structured relations.

  7. Extreme Historical Droughts in the South-Eastern Alps — Analyses Based on Standardised Precipitation Index

    Science.gov (United States)

    Brenčič, Mihael

    2016-10-01

    Droughts are natural phenomena affecting the environment and human activities. There are various drought definitions and quantitative indices; among them is the Standardised Precipitation Index (SPI). In the drought investigations, historical events are poorly characterised and little data are available. To decipher past drought appearances in the southeastern Alps with a focus on Slovenia, precipitation data from HISTALP data repository were taken to identify extreme drought events (SPI ≤ -2.00) from the second half of the 19th century to the present day. Several long-term extreme drought crises were identified in the region (between the years 1888 and 1896; after World War I, during and after World War II). After 1968, drought patterns detected with SPI changed: shorter, extreme droughts with different time patterns appeared. SPI indices of different time spans showed correlated structures in space and between each other, indicating structured relations.

  8. Climatic consequences of adopting drought tolerant vegetation over Los Angeles as a response to California drought

    Science.gov (United States)

    Ban-Weiss, G. A.; Vahmani, P.

    2016-12-01

    During 2012-2014, drought in California resulted in policies to reduce water consumption. One measure pursued was replacing lawns with landscapes that minimize water consumption, such as drought tolerant vegetation. If implemented at broad scale, this strategy would result in reductions in irrigation, and changes in land surface characteristics. In this study, we employ a modified regional climate model to assess the climatic consequences of adopting drought tolerant vegetation over the Los Angeles metropolitan area. Transforming lawns to drought tolerant vegetation resulted in daytime warming of up to 1.9°C, largely due to decreases in irrigation that shifted surface energy partitioning toward higher sensible and lower latent heat flux. During nighttime, however, adopting drought tolerant vegetation caused mean cooling of about 3°C, due to changes in soil thermodynamic properties and heat exchange dynamics between the surface and ground. Our results show that nocturnal cooling effects, which are larger in magnitude and of great importance for public health during heat events, could counterbalance the daytime warming attributed to the studied water conservation strategy. A more aggressive implementation, assuming all urban vegetation was replaced with drought tolerant vegetation, resulted in an average daytime cooling of 0.2°C, largely due to weakened sea-breeze patterns, highlighting the important role of land surface roughness in this coastal megacity.

  9. Drought Responses of Leaf Tissues from Wheat Cultivars of Differing Drought Tolerance at the Metabolite Level

    Institute of Scientific and Technical Information of China (English)

    Jairus B.Bowne; Tim A.Erwin; Juan Juttner; Thorsten Schnurbusch; Peter Langridge; Antony Bacic; Ute Roessner

    2012-01-01

    Drought has serious effects on the physiology of cereal crops.At the cellular and specifically the metabolite level,many individual compounds are increased to provide osmoprotective functions,prevent the dissociation of enzymes,and to decrease the number of reactive oxygen species present in the cell.We have used a targeted GC-MS approach to identify compounds that differ in three different cultivars of bread wheat characterized by different levels of tolerance to drought under drought stress (Kukri,intolerant; Excalibur and RAC875,tolerant).Levels of amino acids,most notably proline,tryptophan,and the branched chain amino acids leucine,isoleucine,and valine were increased under drought stress in all cultivars.In the two tolerant cultivars,a small decrease in a large number of organic acids was also evident.Excalibur,a cultivar genotypically related to Kukri,showed a pattern of response that was more similar to Kukri under well-watered conditions.Under drought stress,Excalibur and RAC875 had a similar response; however,Excalibur did not have the same magnitude of response as RAC875.Here,the results are discussed in the context of previous work in physiological and proteomic analyses of these cultivars under drought stress.

  10. Social perception of droughts in the mass media (southern Spain)

    Science.gov (United States)

    Gross, T. Leon; Ruiz Sinoga, J. D.

    2012-04-01

    In the Mediterranean environment, drought is one of the extreme phenomena that has most direct consequences and complexity. It also has a direct social impact through the mass media, whose analysis, typology and characterization should be a priority in strategies to plan and mitigate effects. The appearance of droughts is slow, their occurrence is often not recognized until human activity and the environment have already been significantly affected, and drought effects persist for a long time after the drought has ended. The spatial distribution of droughts is highly complex, and significant variation in drought conditions is common between different locations. This makes it difficult to identify similar regions, especially in areas of climate transition, where the atmospheric influences are complex. This is the situation in the Iberian Peninsula (particularly the south of the peninsula), which straddles both temperate and sub-tropical climates and in which precipitation is highly variable and spatial variability is substantial. In this study we analyzed rainfall anomalies (Standardized Precipitation Index) over the last 50 years at 4 representative meteorological stations in southern Spain, two on the coast (Málaga and Algarrobo) and two at the headwaters of river basins regulated by dams (Antequera and Periana). The aims of the study were to: i) analyze the types of drought, and their frequency and intensity; and ii) establish the dynamics and evolution of the social perception of droughts in the context of global change, brought about by the communications media. The results showed the SPI was a useful tool for identifying dry anomalies that may feature in our field of study of meteorological and hydrological drought, depending on its duration. Meteorological drought impact on the eco-geomorphological system is common and has had a particular development since the 80's. Hydrological droughts are those that have had the greatest effect on water reserves

  11. Establishing the dominant source of uncertainty in drought indicators

    Science.gov (United States)

    Naumann, G.; Dutra, E.; Barbosa, P.; Pappenberger, F.; Wetterhall, F.; Vogt, J.

    2013-11-01

    Drought monitoring is a key component to mitigate impacts of droughts. Lack of reliable and up-to-date datasets is a common challenge across the Globe. This study investigates different datasets and drought indicators on their capability to improve drought monitoring in Africa. The study was performed for four river basins located in different climatic regions (the Oum er-Rbia in Morocco, the Blue Nile in Eastern Africa, the Upper Niger in Western Africa, and the Limpopo in South-Eastern Africa) as well as the Greater Horn of Africa. The five precipitation datasets compared are the ECMWF ERA - Interim reanalysis, the Tropical Rainfall Measuring Mission satellite monthly rainfall product 3B43, the Global Precipitation Climatology Centre gridded precipitation dataset, the Global Precipitation Climatology Project Global Monthly Merged Precipitation Analyses, and the Climate Prediction Center Merged Analysis of Precipitation. The set of drought indicators used includes the Standardized Precipitation Index, the Standardized Precipitation-Evaporation Index, Soil Moisture Anomalies and Potential Evapotranspiration. A comparison of the annual cycle and monthly precipitation time series shows a good agreement in the timing of the rainy seasons. The main differences between the datasets are in the ability to represent the magnitude of the wet seasons and extremes. Moreover, for the areas affected by drought, all the drought indicators agree on the time of drought onset and recovery although there is disagreement on the extent of the affected area. In regions with limited rain gauge data the estimation of the different drought indicators is characterised by a higher uncertainty. Further comparison suggests that the main source of error in the computation of the drought indicators is the uncertainty in the precipitation datasets rather than the estimation of the distribution parameters of the drought indicators.

  12. Monitoring drought intensity in Illinois with a combined index

    Science.gov (United States)

    Feng, Guanling

    Many traditional drought assessments are conducted based on climate and hydrologic data. The availability and precision of data limit the spatial and temporal resolution and accuracy of derived drought indices. In this study, Vegetation Condition Index (VCI) and Temperature Condition Index (TCI) were generated from Moderate Resolution Imaging Spectroradiometer (MODIS) products. The VCI was derived from Normalized Difference Vegetation Index (NDVI) that was calculated with near infrared and visible red band reflectance from MOD09Q1. The TCI was derived from land surface temperature (LST) product MOD11A2. The VCI and TCI were then combined with reference to the vegetation coverage information from MOD44B to generate the modified Vegetation Health Index (VHI). The modified VHI was applied to quantify the intensity of drought that took place in Illinois from 2000 to 2012. The results showed that the modified VHI identified the major droughts that occurred in Illinois from 2000 to 2012, especially the extreme one taking place in 2012. Moreover, the modified VHI led to the spatial distributions and temporal trends of drought severity, which were overall similar to those from the U.S. Drought Monitor (USDM) maps, but had more detailed spatial variability and much higher spatial resolution. The modified VHI also differentiated the drought impacts between the vegetated and non-vegetated areas, being a lack of the original VHI. Thus, the modified VHI takes advantage of spatially continuous and timely data from satellites and can be applied to conduct the monitoring and detection of drought intensity at local, regional, and national scales. The modified VHI can effectively synthesize the drought information of LST and NDVI to differentiate the effects of land use and land cover (LULC) types and provide the detailed spatial variability of drought intensity and thus enhance the understanding of relationship between drought condition and LULC types.

  13. Diverging trends between meteorological drought indices (SPI and SPEI) in Europe

    Science.gov (United States)

    Stagge, James; Kingston, Daniel; Tallaksen, Lena; Hannah, David

    2016-04-01

    Severe European droughts over the last decade and climate change projections of increased regional drought severity for the Mediterranean and eastern Europe make understanding drought events in a non-stationary climate a major scientific and practical concern for Europe. Additionally, the existence of numerous differing drought metrics is a challenge for the robust detection of drought occurrence trends. This research addresses these issues by testing the hypotheses that (a) there have been recent trends in meteorological drought severity across Europe, and (b) that the choice of drought index significantly affects these observed trends. Meteorological drought is quantified in this study using the 6-month Standardized Precipitation Index (SPI-6) and Standardized Precipitation-Evapotranspiration Index (SPEI-6), which are commonly recommended drought metrics that measure accumulated precipitation and climatic water balance (precipitation minus reference potential evapotranspiration), respectively. Climate data are based on the WATCH Forcing Data (WFD) and WFD ERA-Interim (WFDEI) datasets, which together cover the period 1958-2014. Trends in percentage of European land area in drought were calculated for this 56 year period by defining drought as occurring below the 20th index percentile (SPI/SPEI SPEI-6 drought area have been moderate, with a slight decrease in precipitation-only drought (SPI) area and a slight increase in climatic water balance drought (SPEI) area. The observed spatial trends in drought frequency are consistent with climate model output, with increases in drought frequency for southern Europe and decreases across northern Europe. However, the difference between percentage drought area measured using these two indices has steadily increased. Investigating the constituent climate variables shows that the increasing divergence between drought measured by SPI and SPEI is driven by an increase in temperature and thus PET, which is only accounted for in

  14. Contributions to uncertainty in projections of future drought under climate change scenarios

    Directory of Open Access Journals (Sweden)

    I. H. Taylor

    2012-11-01

    drought projections (0.4%–7%. Despite the large range of uncertainty in drought projections for many regions, projections for some regions have a clear signal, with uncertainty associated with the magnitude of change rather than direction. For instance, a significant increase in time spent in drought is consistently projected for the Amazon, Central America and South Africa whilst projections for Northern India consistently show significant decreases in time spent in drought. We conclude that choice of which drought index (or drought indices to use when undertaking drought impacts assessments is of considerable importance relative to choices relating to the other three included sources of uncertainty in this study. This information will help ensure that future drought impacts assessments are designed appropriately to account for uncertainty.

  15. Drought and groundwater management

    DEFF Research Database (Denmark)

    Amundsen, Eirik S; Jensen, Frank

    This paper considers the problem of a water management authority faced with the threat of a drought that hits at an uncertain date. Three management policies are investigated: i) a laissez-faire (open-access) policy of automatic adjustment through a zero marginal private net benefit condition, ii...

  16. Drought Water Right Curtailment

    Science.gov (United States)

    Walker, W.; Tweet, A.; Magnuson-Skeels, B.; Whittington, C.; Arnold, B.; Lund, J. R.

    2016-12-01

    California's water rights system allocates water based on priority, where lower priority, "junior" rights are curtailed first in a drought. The Drought Water Rights Allocation Tool (DWRAT) was developed to integrate water right allocation models with legal objectives to suggest water rights curtailments during drought. DWRAT incorporates water right use and priorities with a flow-forecasting model to mathematically represent water law and hydrology and suggest water allocations among water rights holders. DWRAT is compiled within an Excel workbook, with an interface and an open-source solver. By implementing California water rights law as an algorithm, DWRAT provides a precise and transparent framework for the complicated and often controversial technical aspects of curtailing water rights use during drought. DWRAT models have been developed for use in the Eel, Russian, and Sacramento river basins. In this study, an initial DWRAT model has been developed for the San Joaquin watershed, which incorporates all water rights holders in the basin and reference gage flows for major tributaries. The San Joaquin DWRAT can assess water allocation reliability by determining probability of rights holders' curtailment for a range of hydrologic conditions. Forecasted flow values can be input to the model to provide decision makers with the ability to make curtailment and water supply strategy decisions. Environmental flow allocations will be further integrated into the model to protect and improve ecosystem water reliability.

  17. A comparative study of historical droughts over Texas, USA and Murray-Darling Basin, Australia: Factors influencing initialization and cessation

    Science.gov (United States)

    Verdon-Kidd, Danielle C.; Scanlon, Bridget R.; Ren, Tong; Fernando, D. Nelun

    2017-02-01

    Water availability and food security are tightly coupled on a global scale. The occurrence of drought puts this balance at risk due to reductions in dryland farming production and water allocations to irrigated agriculture. Improved understanding of drought initiation and cessation would therefore be beneficial for drought planning and management. The study objective was to determine factors affecting drought initiation and cessation over the past century in two climatologically similar regions that represent net agricultural exporters; south central U.S. (Texas) and southeast Australia (Murray Darling Basin, MDB). Drought indices included the Standardized Precipitation Index (SPI, 1900-2014) for meteorological drought, the Normalized Difference Vegetation Index (NDVI, 1981-2014) for agricultural drought, and the Streamflow Drought Index (SDI, 1930-2014) for hydrological drought. Results show that meteorological drought tends to develop gradually over a period of up to six months, with agricultural drought developing shortly thereafter (within one month) in both regions. Evidence of hydrological drought was observed within one month (Texas) and within four months (MDB) on average after meteorological drought was established. Further, droughts appear to cease more quickly than they initiate over Texas, whereas rates of drought initiation and cessation are similar over the MDB. Drought breaking rainfall in Texas is generally a result of a southward shift in the Polar Jet Stream or a low-pressure trough over central North America, whereas drought cessation in the MDB is typically associated with a monsoon trough or low-pressure system in the Tasman Sea/Great Australian Bight. Improved knowledge of the climate mechanisms controlling the onset and termination of drought periods should enhance drought forecasts and improve drought management practices, particularly in regions where water security is a primary objective.

  18. Interacting effects of climate change and habitat fragmentation on drought-sensitive butterflies

    Science.gov (United States)

    Oliver, Tom H.; Marshall, Harry H.; Morecroft, Mike D.; Brereton, Tom; Prudhomme, Christel; Huntingford, Chris

    2015-10-01

    Climate change is expected to increase the frequency of some climatic extremes. These may have drastic impacts on biodiversity, particularly if meteorological thresholds are crossed, leading to population collapses. Should this occur repeatedly, populations may be unable to recover, resulting in local extinctions. Comprehensive time series data on butterflies in Great Britain provide a rare opportunity to quantify population responses to both past severe drought and the interaction with habitat area and fragmentation. Here, we combine this knowledge with future projections from multiple climate models, for different Representative Concentration Pathways (RCPs), and for simultaneous modelled responses to different landscape characteristics. Under RCP8.5, which is associated with `business as usual’ emissions, widespread drought-sensitive butterfly population extinctions could occur as early as 2050. However, by managing landscapes and particularly reducing habitat fragmentation, the probability of persistence until mid-century improves from around zero to between 6 and 42% (95% confidence interval). Achieving persistence with a greater than 50% chance and right through to 2100 is possible only under both low climate change (RCP2.6) and semi-natural habitat restoration. Our data show that, for these drought-sensitive butterflies, persistence is achieved more effectively by restoring semi-natural landscapes to reduce fragmentation, rather than simply focusing on increasing habitat area, but this will only be successful in combination with substantial emission reductions.

  19. Assessing the effectiveness of Multi-Sector Partnerships to manage droughts: The case of the Jucar river basin

    Science.gov (United States)

    Carmona, María.; Máñez Costa, María.; Andreu, Joaquín.; Pulido-Velazquez, Manuel; Haro-Monteagudo, David; Lopez-Nicolas, Antonio; Cremades, Roger

    2017-07-01

    South-east Spain is a drought prone area, characterized by climate variability and water scarcity. The Jucar River Basin, located in Eastern Spain, has suffered many historical droughts with significant socio-economic impacts. For nearly a hundred years, the institutional and non-institutional strategies to cope with droughts have been successful through the development of institutions and partnerships for drought management including multiple actors. In this paper, we show how the creation and institutionalisation of Multi-Sector Partnerships (MSPs) has supported the development of an efficient drought management. Furthermore, we analyze the performance of one of the suggested instruments by the partnership related to drought management in the basin. Two methodologies are used for these purposes. On one hand, the Capital Approach Framework to analyze the effectiveness of the governance processes in a particular partnership (Permanent Drought Commission), which aims to highlight the governance strength and weakness of the MSP for enhancing drought management in the Jucar River Basin. Through a dynamic analysis of the changes that the partnership has undergone over time to successfully deal with droughts, its effectiveness on drought management is demonstrated. On the other hand, an econometric approach is used to analyze the economic efficiency of the emergency drought wells as one of the key drought mitigation measures suggested by the Permanent Drought Commission and implemented. The results demonstrate the potential and efficiency of applying drought wells as mitigation measures (significant reduction of economic losses, around 50 M€ during the drought period, 2005-2008).

  20. Comparative analysis of expressed sequence tags (ESTs between drought-tolerant and -susceptible genotypes of chickpea under terminal drought stress

    Directory of Open Access Journals (Sweden)

    Raju N L

    2011-04-01

    Full Text Available Abstract Background Chickpea (Cicer arietinum L. is an important grain-legume crop that is mainly grown in rainfed areas, where terminal drought is a major constraint to its productivity. We generated expressed sequence tags (ESTs by suppression subtraction hybridization (SSH to identify differentially expressed genes in drought-tolerant and -susceptible genotypes in chickpea. Results EST libraries were generated by SSH from root and shoot tissues of IC4958 (drought tolerant and ICC 1882 (drought resistant exposed to terminal drought conditions by the dry down method. SSH libraries were also constructed by using 2 sets of bulks prepared from the RNA of root tissues from selected recombinant inbred lines (RILs (10 each for the extreme high and low root biomass phenotype. A total of 3062 unigenes (638 contigs and 2424 singletons, 51.4% of which were novel in chickpea, were derived by cluster assembly and sequence alignment of 5949 ESTs. Only 2185 (71% unigenes showed significant BLASTX similarity ( Conclusion Our study compares not only genes that are up- and down-regulated in a drought-tolerant genotype under terminal drought stress and a drought susceptible genotype but also between the bulks of the selected RILs exhibiting extreme phenotypes. More than 50% of the genes identified have been shown to be associated with drought stress in chickpea for the first time. This study not only serves as resource for marker discovery, but can provide a better insight into the selection of candidate genes (both up- and downregulated associated with drought tolerance. These results can be used to identify suitable targets for manipulating the drought-tolerance trait in chickpea.

  1. Responses of ABA and CTK to soil drought in leafless and leafy apple tree

    Institute of Scientific and Technical Information of China (English)

    李岩; 潘海春; 李德全

    2003-01-01

    The authors tested the contents of ABA (abscisic acid), ZR (zeatin riboside), DHZR (dihydrozeatin riboside) and iPA (isopentenyl adenosine) in leafless and leafy apple trees (Red Fuji/Malus micromalus Makino) during soil drought stress. ABA concentration in drought stressed leafless trees increased significantly compared to the controls. ABA both in roots and xylem rose steadily in the earlier drought stage, reaching a maximum of 1.46±0.35 nmol g\\+-1FW and 117 nmol l\\+-1 after the 8th day. Similar change patterns of ABA concentration was observed in the leafy trees during soil drought stress; ABA concentrations in roots and xylem sap increased and reached the maximum in the first three days; after 8th day , it decreased slightly, whereas leaf ABA concentration increased steadily in drought stressed plants throughout the duration of the experiment. Between drought stressed and control trees, no significant differences were observed in concentration of ZR and DHZR in both leafless and leafy trees; whereas iPA concentration of the drought stressed leafless and leafy plants decreased markedly in the later stage of drought. These results showed that endogenous ABA originated mainly from the roots in the earlier drought stage, and mainly from the leaves in the later drought stage. Total CTK showed no reduction in the earlier drought stage and decreased in the later drought stage.

  2. Evaluation of drought indices via remotely sensed data with hydrological variables

    Science.gov (United States)

    Choi, Minha; Jacobs, Jennifer M.; Anderson, Martha C.; Bosch, David D.

    2013-01-01

    SummaryAn intercomparison among standard and remotely sensed drought indices was conducted using streamflow and soil moisture measurements collected in the Little River Experimental Watershed, Georgia, US, during the period from 2000 to 2008. All drought indices exhibited a linear, monotonic association with soil moisture, but there was a non-linear monotonic association between the drought indices and streamflow. Of the indices examined, the Evaporative Stress Index (ESI) showed reasonable performance with about 90% accuracy capturing moderate drought conditions and 80% accuracy capturing severe drought conditions in comparison to observed soil moisture and streamflow. While the ability of the ESI to capture shorter term droughts is equal or superior to the Palmer Drought Severity Index (PDSI) when characterizing droughts based on soil moisture and streamflow thresholds, the accuracy of the ESI was less efficient in the case of severe droughts. A drought index developed from the Advanced Microwave Scanning Radiometer (AMSR-E) soil moisture product showed reasonable correlations with the observed soil moisture and streamflow. However the ESI, Vegetation Health Index (VHI), and PDSI demonstrated greater skill in detecting drought in this study region. Multi-variable linear regression models revealed that the joint use of PDSI and appropriate remote sensing products improved predictions of observed hydrologic variables. Overall, the ESI was identified as a promising drought index for characterizing streamflow and soil moisture anomalies, particularly in regions where precipitation observations are unavailable, sparsely distributed, or biased with respect to regional averages.

  3. Responses of ABA and CTK to soil drought in leafless and leafy apple tree

    Institute of Scientific and Technical Information of China (English)

    李岩; 潘海春; 李德全

    2003-01-01

    The authors tested the contents of ABA (abscisic acid) , ZR (zeatin riboside), DHZR (dihydrozeatin riboside) and iPA (isopentenyl adenosine) in leafless and leafy apple trees ( Red Fufi/Malus micromalus Makino) during soil drought stress. ABA concentration in drought stressed leafless trees increased significantly compared to the controls. ABA both in roots and xylem rose steadily in the earlier drought stage, reaching a maximum of 1.46 ± 0.35 nmol g-1 FW and 117 nmol l-1 after the 8th day. Similar change patterns of ABA concentration was observed in the leafy trees during soil drought stress; ABA concentrations in roots and xylem sap increased and reached the maximum in the first three days; after 8th day , it decreased slightly, whereas leaf ABA concentration increased steadily in drought stressed plants throughout the duration of the experiment.Between drought stressed and control trees, no significant differences were observed in concentration of ZR and DHZR in both leafless and leafy trees ; whereas iPA concentration of the drought stressed leafless and leafy plants decreased markedly in the later stage of drought. These results showed that endogenous ABA originated mainly from the roots in the earlier drought stage, and mainly from the leaves in the later drought stage. Total CTK showed no reduction in the earlier drought stage and decreased in the later drought stage.

  4. Space-time Trends in U.S. Meteorological Droughts

    CERN Document Server

    Ganguli, Poulomi

    2015-01-01

    Understanding droughts in a climate context remains a major challenge. Over the United States, different choices of observations and metrics have often produced diametrically opposite insights. This paper focuses on understanding and characterizing meteorological droughts from station measurements of precipitation. The Standardized Precipitation Index is computed and analyzed to obtain drought severity, duration and frequency. Average drought severity trends are found to be uncertain and data-dependent. Furthermore, the mean and spatial variance do not show any discernible non-stationary behavior. However, the spatial coverage of extreme meteorological droughts in the United States exhibits an increasing trend over nearly all of the last century. Furthermore, the coverage over the last half decade exceeds that of the dust bowl era. Previous literature suggests that climate extremes do not necessarily follow the trends or uncertainties exhibited by the averages. While this possibility has been suggested for dr...

  5. Biomass-dependent susceptibility to drought in experimental grassland communities.

    Science.gov (United States)

    Wang, Yongfan; Yu, Shixiao; Wang, Jiang

    2007-05-01

    Earlier studies indicated that plant diversity influences community resistance in biomass when ecosystems are exposed to perturbations. This relationship remains controversial, however. Here we constructed grassland communities to test the relationships between species diversity and productivity under control and experimental drought conditions. Species richness was not correlated with biomass either under constant conditions or under drought conditions. However, communities with lower biomass production were more resistant to drought stress than those that were more productive. Our results also showed that ecosystem resistance to drought is a decreasing but nonlinear function of biomass. In contrast, species diversity had little and an equivocal effect on ecosystem resistance. From the results reported here, and the results of several previous studies, we suggest that high biomass systems exhibited a greater biomass reduction in response to drought than low biomass systems did, regardless of the relationship between plant diversity and community biomass production.

  6. Is Snowpack Drought an Increasing Threat in the Pacific Northwest?

    Science.gov (United States)

    Barik, M. G.; Liu, M.; Stockle, C.; Abatzoglou, J. T.; Adam, J. C.

    2015-12-01

    In spite of near normal precipitation during the winter of water year 2015, the Pacific Northwest (PNW) has experienced drought because of insufficient snow accumulation in the mountains, which was exacerbated by an unusually warm and dry summer. Low mountain snowpack resulted from an anomalously warm winter and subsequently affected water supply for irrigation, fish habitat, ecosystem, and recreation, necessitating a statewide drought emergency declaration in the Washington State. While the 2015 drought is likely a result of natural variability superposed with climate warming, we ask how the frequency of droughts of this character are likely to change as a result of anthropogenic climate change. Downscaled climate data from multiple Global Climate Models from the Fifth Climate Model Intercomparison Project were used with the Variable Infiltration Capacity (VIC) model to calculate both the Standardized Precipitation Index (SPI) and Snow Melt and Rain Index (SMRI) indices for quantifying meteorological and snowpack droughts, respectively, in the Columbia River Basin (CRB) under historic and future climate change scenarios. Our results show that snowpack droughts increase in severity and frequency in the future in response to the sensitivity of the snowpack to warming, whereas there is a less systematic trend in meteorological drought. Water resources in the CRB largely depend on the mountain snowpack and spring snowmelt. More frequent occurrence of snowpack drought will have serious implications in this system, which need to be addressed in future studies.

  7. Hydrological drought frequency analysis of the Yom River, Thailand

    Directory of Open Access Journals (Sweden)

    Kanokporn Sawatpru

    2016-06-01

    Full Text Available The Yom River is subjected to flood and drought annually each for half a year. Several works suggested storing water during the surplus season for use in the dry season. None of them, however, quantified the precise amounts of suggested storage along the river with acceptable risk. In an attempt to quantify storage, we performed frequency analyses to find out severity of streamflow droughts along the river. A deficit volume, the amount of flow being less than a selected threshold level, was used to characterize a drought event. The Weibull distribution model was chosen for analysis after comparison with lognormal and Pareto models to the empirical distribution. Results show a more severe drought condition toward the downstream section of the river where paddy fields get larger. A large deep groundwater irrigation project located about the mid-section of the river mitigates drought along this section. Drought is more severe further downstream from the project, one reason being the baseflow is cut off by the groundwater abstraction. This presented method can help to quantify severity of hydrological drought along any river therefore its drought management can be undertaken.

  8. Contrasting drought-response strategies in California redwoods.

    Science.gov (United States)

    Ambrose, Anthony R; Baxter, Wendy L; Wong, Christopher S; Næsborg, Rikke R; Williams, Cameron B; Dawson, Todd E

    2015-05-01

    We compared the physiology and growth of seedlings originating from different Sequoia sempervirens (D. Don.) Endl. (coast redwood) and Sequoiadendron giganteum (Lindl.) Buchh. (giant sequoia) populations subjected to progressive drought followed by a recovery period in a controlled greenhouse experiment. Our objective was to examine how multiple plant traits interact to influence the response of seedlings of each species and seed population to a single drought and recovery cycle. We measured soil and plant water status, leaf gas exchange, stem embolism and growth of control (well-watered) and drought-stressed (water withheld) seedlings from each population at the beginning, middle and end of a 6-week drought period and again 2 weeks after re-watering. The drought had a significant effect on many aspects of seedling performance, but water-stressed seedlings regained most physiological functioning by the end of the recovery period. Sequoiadendron seedlings exhibited a greater degree of isohydry (water status regulation), lower levels of stem embolism, higher biomass allocation to roots and lower sensitivity of growth to drought compared with Sequoia. Only minor intra-specific differences were observed among populations. Our results show that seedlings of the two redwood species exhibit contrasting drought-response strategies that align with the environmental conditions these trees experience in their native habitats, and demonstrate trade-offs and coordination among traits affecting plant water use, carbon gain and growth under drought.

  9. Human influence on meteorological drought risk in Europe

    Science.gov (United States)

    Gudmundsson, L.; Seneviratne, S. I.

    2015-12-01

    Drought has affected 37% of the European Union's territory in the past three decades, triggering ecological and socio-economic damages and impacting more than 100 billion inhabitants. Climate change simulations project increased drought risk in southern Europe, and on the other hand decreased drought risk in the norther of the continent. Observed changes in water balance components and drought indicators do resemble the projected pattern. However, assessments of possible causes of the reported regional changes have yet been inconclusive. To resolve this, we first employ a data driven approach and estimate how the probability of exceptionally dry years is related to global warming. The results confirm that it is very likely that that drought risk in the Mediterranean has increased in response to global warming, whereas it is very likely that drought risk has decreased in Northern Europe. Subsequently we show that observed changes in drought risk can only be captured by climate models if anthropogenic radiative forcing is accounted for. The consistency of the observational estimates with model simulations suggests that it is very likely that past changes in drought risk are attributable to anthropogenic effects on the climate.

  10. Warm Spring Reduced Impact of Summer Drought on Carbon Cycling

    Science.gov (United States)

    Wolf, Sebastian; Keenan, Trevor F.; Fisher, Joshua B.; Baldocchi, Dennis

    2015-04-01

    Drought severely impacts biosphere-atmosphere carbon and water fluxes of terrestrial ecosystems by reducing productivity, carbon uptake and water transport to the atmosphere. The 2012 US drought was among the most intense and widespread drought events in the U.S. since the 'Dust Bowl' period in the 1930s, and had devastating effects on agricultural production. In addition, 2012 was among the warmest years on record. Using eddy covariance measurements of carbon, water and energy exchange from AmeriFlux sites along with remote sensing products, we show that this summer drought substantially reduced ecosystem productivity, net carbon uptake and water transport to the atmosphere. However, the warm spring with higher ecosystem productivity reduced the impact of the summer drought on annual carbon uptake. Shifts in vegetation activity during spring also triggered feedbacks that contributed to the summer heatwave. Although the drought was exceptional, 2012 was an example of what is expected in terms of future climate change - i.e. warmer temperatures all year and an increased frequency and duration of drought in summer. Understanding the response of ecosystem carbon and water cycling to drought will help to mitigate these changes, and our study provides important new insights for that.

  11. A nonparametric multivariate standardized drought index for characterizing socioeconomic drought: A case study in the Heihe River Basin

    Science.gov (United States)

    Huang, Shengzhi; Huang, Qiang; Leng, Guoyong; Liu, Saiyan

    2016-11-01

    Among various drought types, socioeconomic drought is the least investigated type of droughts. Most existing drought indicators ignore the role of local reservoirs and water demand in coping with climatic extremes. In this study, a Multivariate Standardized Reliability and Resilience Index (MSRRI) combining inflow-demand reliability index (IDR) and water storage resilience index (WSR) was applied to examine the evolution characteristics of the socioeconomic droughts in the Heihe River Basin, the second largest inland river basin in northwestern China. Furthermore, the cross wavelet analysis was adopted to explore the associations between annual MSRRI series and El Niño Southern Oscillation (ENSO)/Atlantic Oscillation (AO). Results indicated that: (1) the developed MSRRI is more sensitive to the onset and termination of socioeconomic droughts than IDR and WSR, owing to its joint distribution function of IDR and WSR, responding to changes in either or both of the indices; (2) the MSRRI series in the Heihe River Basin shows non-significant trends at both monthly and annual scales; (3) both ENSO and AO contribute to the changes in the socioeconomic droughts in the Heihe River Basin, and the impacts of ENSO on the socioeconomic droughts are stronger than those of AO.

  12. Drought Assessment in Zacatecas, Mexico

    Directory of Open Access Journals (Sweden)

    Carlos Bautista-Capetillo

    2016-09-01

    Full Text Available Water has always been an essential development factor for civilizations, but its erratic distribution in space and time has caused severe socio-economic problems throughout human history due to both scarcity and excess. In Mexico, insufficient rainwater to satisfy crop water requirements is a recurrent phenomenon. From a meteorological perspective, drought refers to a decay of the rainfall–runoff process below normal values, resulting in lower availability of water resources to satisfy the needs of human activities, particularly those related to agriculture and livestock. This research reports on drought assessment for Zacatecas, Mexico using monthly data from 111 weather stations with temperature and precipitation information from a 33-year period. Drought was characterized by applying the Standardized Precipitation Index and the Reconnaissance Drought Index using 3, 6, and 12 month timescales; both indexes were plotted and mapped for the period 2005 to 2014. The trend indicates rainfall anomalies (from incipient drought to severe drought in 6 or 7 years, depending of the selected timescale. April was selected to start the drought analysis because it is the month when farmers usually establish rainfed crops in the region. In ten years, Zacatecas has lost 478 million US dollars due to drought. 2005, 2009, and 2011 were the most critical years, with 47%, 39%, and 63% losses in agricultural income. Such values are in agreement with drought severity estimates: 2005 and 2011 were both dry years (drought indexes were less than −1.25 in the whole territory.

  13. ASSESSMENT OF DROUGHT TOLERANCE IN FEW CLONES OF NATURAL RUBBER (Hevea brasiliensis UNDER DRY HOT CLIMATE OF ODISHA, INDIA

    Directory of Open Access Journals (Sweden)

    Krishan B

    2017-02-01

    Full Text Available A preliminary study was conducted to assess the drought tolerance at the early stages of growth in different clones of natural rubber (Hevea brasiliensis at the Regional Research Station of Rubber Research Institute of India at Kadalipal, Dhenkanal, Odisha in eastern region of India. Poly bag plants of five clones RRII 430, RRII 105, RRIM 600, RRII 208 and IRCA 111 were assessed for the drought tolerance and compared drought injury indices status with same clones growing naturally in the adjoining field. Results of drought injury indicated scorching, leaf yellowing, drying and leaf fall at regular intervals, since imposition of drought stress conditions. Among various tested clones RRIM 600 and RRII 430 have comparatively higher drought tolerant. Plants under field condition showed drought injury symptoms much later than the poly bag plants. Drought indices, tolerance of drought of different clones and possible reasons have been also discussed

  14. The asymmetric impact of global warming on US drought types and distributions in a large ensemble of 97 hydro-climatic simulations.

    Science.gov (United States)

    Huang, Shengzhi; Leng, Guoyong; Huang, Qiang; Xie, Yangyang; Liu, Saiyan; Meng, Erhao; Li, Pei

    2017-07-19

    Projection of future drought is often involved large uncertainties from climate models, emission scenarios as well as drought definitions. In this study, we investigate changes in future droughts in the conterminous United States based on 97 1/8 degree hydro-climate model projections. Instead of focusing on a specific drought type, we investigate changes in meteorological, agricultural, and hydrological drought as well as the concurrences. Agricultural and hydrological droughts are projected to become more frequent with increase in global mean temperature, while less meteorological drought is expected. Changes in drought intensity scale linearly with global temperature rises under RCP8.5 scenario, indicating the potential feasibility to derive future drought severity given certain global warming amount under this scenario. Changing pattern of concurrent droughts generally follows that of agricultural and hydrological droughts. Under the 1.5 °C warming target as advocated in recent Paris agreement, several hot spot regions experiencing highest droughts are identified. Extreme droughts show similar patterns but with much larger magnitude than the climatology. This study highlights the distinct response of droughts of various types to global warming and the asymmetric impact of global warming on drought distribution resulting in a much stronger influence on extreme drought than on mean drought.

  15. Evaluation of Agronomic Traits in Chromosome Segment Substitution Lines of KDML105 Containing Drought Tolerance QTL under Drought Stress

    Institute of Scientific and Technical Information of China (English)

    Vaiphot KANJOO; Kanchana PUNYAWAEW; Jonaliza L. SIANGLIW; Suwat JEARAKONGMAN; Apichart VANAVICHIT; Theerayut TOOJINDA

    2012-01-01

    Drought is a major abiotic constraint to rice production in rainfed lowland and insufficiently irrigated areas.The improvement of drought tolerant varieties is one of the strategies to reduce the negative effects of drought.Quantitative trait loci (QTLs) for primary and secondary traits related to drought toleranco (DT) on chromosomes 1,3,4,8 and 9 that determined from double haploid lines derived from a cross between CT9993 and IR62266 were introgressed and dissected into small pieces in the genetic background of Khao Dawk Mali 105 (KDML105) to develop chromosome segment substitution line (CSSL) population.The CSSLs were evaluated at the reproductive stage for their agronomic performance and yield components under drought stress,and results were compared with irrigated condition.The flowering of CSSL lines was 6 to 7 d earlier than KDML105.The mean values of grain yields in the CSSLs were higher than KDML105 under drought and irrigated conditions.At irrigated condition,the grain yields of introgression lines carrying DT-QTLs from chromosomes 4 and 8 were higher than that of KDML105,whereas other traits showed little difference with KDML105.Analysis indicated that grain yield has positive correlation with plant height,tiller and panicle number per plant,and total grain weight per plant under drought stress while negatively correlated with days to flowering.As mentioned above,CSSLs showing good adaptation under drought stress can be used as genetic materials to improve drought tolerance in Thai rainfed lowland rice breeding program,and as materials to dissect genes underlying drought tolerance.

  16. Measuring drought and drought impacts in Red Sea Province, Sudan

    OpenAIRE

    Cole, R.

    1989-01-01

    Metadata only record The report assesses the 1987 and 1988 drought in Red Sea Province, Sudan putting it in the wider context of other droughts and floods, and the impact of food aid on the province. There are three major coping strategies employed in times of drought, which are essentially intensification of activities already performed. The first of these involves food consumption reduction, the consumption of bush foods, borrowing, the sale of livestock, and herd splitting. The medial r...

  17. Expansion of protein domain repeats.

    Directory of Open Access Journals (Sweden)

    Asa K Björklund

    2006-08-01

    Full Text Available Many proteins, especially in eukaryotes, contain tandem repeats of several domains from the same family. These repeats have a variety of binding properties and are involved in protein-protein interactions as well as binding to other ligands such as DNA and RNA. The rapid expansion of protein domain repeats is assumed to have evolved through internal tandem duplications. However, the exact mechanisms behind these tandem duplications are not well-understood. Here, we have studied the evolution, function, protein structure, gene structure, and phylogenetic distribution of domain repeats. For this purpose we have assigned Pfam-A domain families to 24 proteomes with more sensitive domain assignments in the repeat regions. These assignments confirmed previous findings that eukaryotes, and in particular vertebrates, contain a much higher fraction of proteins with repeats compared with prokaryotes. The internal sequence similarity in each protein revealed that the domain repeats are often expanded through duplications of several domains at a time, while the duplication of one domain is less common. Many of the repeats appear to have been duplicated in the middle of the repeat region. This is in strong contrast to the evolution of other proteins that mainly works through additions of single domains at either terminus. Further, we found that some domain families show distinct duplication patterns, e.g., nebulin domains have mainly been expanded with a unit of seven domains at a time, while duplications of other domain families involve varying numbers of domains. Finally, no common mechanism for the expansion of all repeats could be detected. We found that the duplication patterns show no dependence on the size of the domains. Further, repeat expansion in some families can possibly be explained by shuffling of exons. However, exon shuffling could not have created all repeats.

  18. The complex influence of ENSO on droughts in Ecuador

    KAUST Repository

    Vicente-Serrano, S. M.

    2016-03-26

    In this study, we analyzed the influence of El Niño–Southern Oscillation (ENSO) on the spatio-temporal variability of droughts in Ecuador for a 48-year period (1965–2012). Droughts were quantified from 22 high-quality and homogenized time series of precipitation and air temperature by means of the Standardized Precipitation Evapotranspiration Index. In addition, the propagation of two different ENSO indices (El Niño 3.4 and El Niño 1 + 2 indices) and other atmospheric circulation processes (e.g., vertical velocity) on different time-scales of drought severity were investigated. The results showed a very complex influence of ENSO on drought behavior across Ecuador, with two regional patterns in the evolution of droughts: (1) the Andean chain with no changes in drought severity, and (2) the Western plains with less severe and frequent droughts. We also detected that drought variability in the Andes mountains is explained by the El Niño 3.4 index [sea surface temperature (SST) anomalies in the central Pacific], whereas the Western plains are much more driven by El Niño 1 + 2 index (SST anomalies in the eastern Pacific). Moreover, it was also observed that El Niño and La Niña phases enhance droughts in the Andes and Western plains regions, respectively. The results of this work could be crucial for predicting and monitoring drought variability and intensity in Ecuador. © 2016 Springer-Verlag Berlin Heidelberg

  19. Multilevel and multiscale drought reanalysis over France with the Safran-Isba-Modcou hydrometeorological suite

    Directory of Open Access Journals (Sweden)

    J.-P. Vidal

    2010-03-01

    Full Text Available Physically-based droughts can be defined as a water deficit in at least one component of the land surface hydrological cycle. The reliance of different activity domains (water supply, irrigation, hydropower, etc. on specific components of this cycle requires drought monitoring to be based on indices related to meteorological, agricultural, and hydrological droughts. This paper describes a high-resolution retrospective analysis of such droughts in France over the last fifty years, based on the Safran-Isba-Modcou (SIM hydrometeorological suite. The high-resolution 1958–2008 Safran atmospheric reanalysis was used to force the Isba land surface scheme and the hydrogeological model Modcou. Meteorological droughts are characterized with the Standardized Precipitation Index (SPI at time scales varying from 1 to 24 months. Similar standardizing methods were applied to soil moisture and streamflow for identifying multiscale agricultural droughts – through the Standardized Soil Wetness Index (SSWI – and multiscale hydrological droughts, through the Standardized Flow Index (SFI. Based on a common threshold level for all indices, drought event statistics over the 50-yr period – number of events, duration, severity and magnitude – have been derived locally in order to highlight regional differences at multiple time scales and at multiple levels of the hydrological cycle (precipitation, soil moisture, streamflow. Results show a substantial variety of temporal drought patterns over the country that are highly dependent on both the variable and time scale considered. Independent spatio-temporal drought events have then been identified and described by combining local characteristics with the evolution of area under drought. Summary statistics have finally been used to compare past severe drought events, from multi-year precipitation deficits (1989–1990 to short hot and dry periods (2003. Results show that the ranking of drought events depends highly

  20. Lags in hydrologic recovery following an extreme drought: Assessing the roles of climate and catchment characteristics

    Science.gov (United States)

    Yang, Yuting; McVicar, Tim R.; Donohue, Randall J.; Zhang, Yongqiang; Roderick, Michael L.; Chiew, Francis H. S.; Zhang, Lu; Zhang, Junlong

    2017-06-01

    Drought, generally characterized by below-average water supply, propagates through the hydrologic system with consequent ecological and societal impacts. Compared with other drought aspects, the recovery of drought especially in the hydrological components, which directly relates to the recovery of water resources for agricultural, ecological and human needs, is less-understood. Here, taking the Millennium drought in southeast Australia (˜1997-2009) as an illustrating case, we comprehensively examined multiple aspects of the meteorological (i.e., precipitation) and hydrological (i.e., streamflow and base flow) droughts across 130 unimpaired catchments using long-term hydro-meteorological observations. Results show that the duration and intensity of the meteorological drought are both lengthened and amplified in the hydrological drought, suggesting a nonstationarity in the rainfall-runoff relationship during a prolonged drought. Additionally, we find a time lag commonly exists between the end of the meteorological droughts and the end of the hydrological drought, with the recovery of base flow showing a longer lag than the recovery of streamflow. The recovery rate of precipitation after drought was found to be the dominant factor that controls the recovery of hydrological droughts while catchment landscape (i.e., valley bottom flatness) plays an important but secondary role in controlling the lags in the hydrological recovery. Other hydro-climatic factors and catchment properties appear to have only minor influences governing hydrological drought recovery. Our findings highlight a delayed response in the terrestrial components of the hydrological cycle to precipitation after prolonged drought, and provide valuable scientific guidance to water resources management and water security assessment in regions facing future droughts.

  1. Phloem transport and drought.

    Science.gov (United States)

    Sevanto, Sanna

    2014-04-01

    Drought challenges plant water uptake and the vascular system. In the xylem it causes embolism that impairs water transport from the soil to the leaves and, if uncontrolled, may even lead to plant mortality via hydraulic failure. What happens in the phloem, however, is less clear because measuring phloem transport is still a significant challenge to plant science. In all vascular plants, phloem and xylem tissues are located next to each other, and there is clear evidence that these tissues exchange water. Therefore, drought should also lead to water shortage in the phloem. In this review, theories used in phloem transport models have been applied to drought conditions, with the goal of shedding light on how phloem transport failure might occur. The review revealed that phloem failure could occur either because of viscosity build-up at the source sites or by a failure to maintain phloem water status and cell turgor. Which one of these dominates depends on the hydraulic permeability of phloem conduit walls. Impermeable walls will lead to viscosity build-up affecting flow rates, while permeable walls make the plant more susceptible to phloem turgor failure. Current empirical evidence suggests that phloem failure resulting from phloem turgor collapse is the more likely mechanism at least in relatively isohydric plants.

  2. Paradigms and public policies on drought in northeast Brazil: a historical perspective.

    Science.gov (United States)

    Campos, José Nilson B

    2015-05-01

    This paper describes the evolution of drought-related public policies in Northeast Brazil (NEB). Using a historical approach, we show that the evolution of public policy has not been characterized by abrupt shifts, but has instead been shaped through debates between renowned intellectuals. The resulting public policies formed a hydrological infrastructure that delivers clean water needed for robust economic activity. However, outcomes of the 2012-2013 drought show that populations that depend on rain fed agriculture are as vulnerable to drought as they were at the start of the 20th century. Although government, social, and emergency programs have aided drought victims, drought analysts agree that rain fed agriculture has remained vulnerable since drought policies were first formulated. Drought policies formulate integrated water resources management (IWRM) strategies that are geared toward supplying safe drinking water, and debates surrounding the IWRM paradigm have been affected by outcomes of major international events such as the World Water Forum.

  3. Assessing various drought indicators in representing drought in boreal forests in Finland

    Science.gov (United States)

    Gao, Y.; Markkanen, T.; Thum, T.; Aurela, M.; Lohila, A.; Mammarella, I.; Hagemann, S.; Aalto, T.

    2015-08-01

    Droughts can impact on forest functioning and production, and even lead to tree mortality. However, drought is an elusive phenomenon that is difficult to quantify and define universally. In this study, we assessed the performance of a set of indicators that have been used to describe drought conditions in the summer months (June, July, August) over a 30 year period (1981-2010) in Finland. Those indicators include the Standardized Precipitation Index (SPI), the Standardized Precipitation-Evapotranspiration Index (SPEI), the Soil Moisture Index (SMI) and the Soil Moisture Anomaly (SMA). Herein, regional soil moisture was produced by the land surface model JSBACH. While SPI, SPEI, and SMA show a degree of anomalies from the statistical means over a period, SMI is directly connected to plant available water and closely dependent on soil properties. Moreover, the buffering effect of soil moisture and the associated soil moisture memory can impact on the onset and duration of drought as indicated by the SMI and SMA, whereas SPI and SPEI are directly controlled by meteorological conditions. In particular, we investigated whether the SMI, SMA and SPEI are able to indicate the Extreme Drought affecting Forest health (EDF) in Finland. EDF thresholds for these indicators are suggested, based on the spatially representative statistics of forest health observations in the exceptional dry year 2006. Our results showed that SMI was the best indicator in capturing the spatial extent of forest damage induced by the extreme drought in 2006. In addition, the derived thresholds were applied to those indicators to capture EDF events over the summer months of the 30 year study period. The SPEI and SMA showed more frequent EDF events over the 30 year period, and typically described a higher fraction of influenced area than SMI. In general, the suggested EDF thresholds for those indicators may be used for the indication of EDF events in Finland or other boreal forests areas in the context

  4. Assessing various drought indicators in representing drought in boreal forests in Finland

    Directory of Open Access Journals (Sweden)

    Y. Gao

    2015-08-01

    Full Text Available Droughts can impact on forest functioning and production, and even lead to tree mortality. However, drought is an elusive phenomenon that is difficult to quantify and define universally. In this study, we assessed the performance of a set of indicators that have been used to describe drought conditions in the summer months (June, July, August over a 30 year period (1981–2010 in Finland. Those indicators include the Standardized Precipitation Index (SPI, the Standardized Precipitation–Evapotranspiration Index (SPEI, the Soil Moisture Index (SMI and the Soil Moisture Anomaly (SMA. Herein, regional soil moisture was produced by the land surface model JSBACH. While SPI, SPEI, and SMA show a degree of anomalies from the statistical means over a period, SMI is directly connected to plant available water and closely dependent on soil properties. Moreover, the buffering effect of soil moisture and the associated soil moisture memory can impact on the onset and duration of drought as indicated by the SMI and SMA, whereas SPI and SPEI are directly controlled by meteorological conditions. In particular, we investigated whether the SMI, SMA and SPEI are able to indicate the Extreme Drought affecting Forest health (EDF in Finland. EDF thresholds for these indicators are suggested, based on the spatially representative statistics of forest health observations in the exceptional dry year 2006. Our results showed that SMI was the best indicator in capturing the spatial extent of forest damage induced by the extreme drought in 2006. In addition, the derived thresholds were applied to those indicators to capture EDF events over the summer months of the 30 year study period. The SPEI and SMA showed more frequent EDF events over the 30 year period, and typically described a higher fraction of influenced area than SMI. In general, the suggested EDF thresholds for those indicators may be used for the indication of EDF events in Finland or other boreal forests

  5. Climate Prediction Center (CPC) Monthly Drought Outlook (MDO)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A CPC forecaster (from a rotating schedule of 5 as of August 2013) creates the Monthly Drought Outlook map and narratives. The map, produced using GIS, shows where...

  6. MRI in a patient with the Worster-Drought syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Arbelaez, A.; Castillo, M. [Department of Radiology, University of North Carolina School of Medicine, Chapel Hill, NC 27599-7510 (United States); Tennison, M. [Department of Neurology, University of North Carolina School of Medicine, Chapel Hill, NC 27599 (United States)

    2000-06-01

    We describe a patient with the Worster-Drought syndrome (congenital suprabulbar paresis), thought to be a failure of development of the corticobulbar tracts. MRI showed bilateral perisylvian cortical dysplasia. (orig.)

  7. Drought Variability and Land Degradation in Semiarid Regions: Assessment Using Remote Sensing Data and Drought Indices (1982–2011)

    KAUST Repository

    Vicente-Serrano, Sergio

    2015-04-14

    We analyzed potential land degradation processes in semiarid regions worldwide using long time series of remote sensing images and the Normalized Difference Vegetation Index (NDVI) for the period 1981 to 2011. The objectives of the study were to identify semiarid regions showing a marked decrease in potential vegetation activity, indicative of the occurrence of land degradation processes, and to assess the possible influence of the observed drought trends quantified using the Standardized Precipitation Evapotranspiration Index (SPEI). We found that the NDVI values recorded during the period of maximum vegetation activity (NDVImax) predominantly showed a positive evolution in the majority of the semiarid regions assessed, but NDVImax was highly correlated with drought variability, and the trends of drought events influenced trends in NDVImax at the global scale. The semiarid regions that showed most increase in NDVImax (the Sahel, northern Australia, South Africa) were characterized by a clear positive trend in the SPEI values, indicative of conditions of greater humidity and lesser drought conditions. While changes in drought severity may be an important driver of NDVI trends and land degradation processes in semiarid regions worldwide, drought did not apparently explain some of the observed changes in NDVImax. This reflects the complexity of vegetation activity processes in the world’s semiarid regions, and the difficulty of defining a universal response to drought in these regions, where a number of factors (natural and anthropogenic) may also affect on land degradation.

  8. Drought Variability and Land Degradation in Semiarid Regions: Assessment Using Remote Sensing Data and Drought Indices (1982–2011

    Directory of Open Access Journals (Sweden)

    Sergio M. Vicente-Serrano

    2015-04-01

    Full Text Available We analyzed potential land degradation processes in semiarid regions worldwide using long time series of remote sensing images and the Normalized Difference Vegetation Index (NDVI for the period 1981 to 2011. The objectives of the study were to identify semiarid regions showing a marked decrease in potential vegetation activity, indicative of the occurrence of land degradation processes, and to assess the possible influence of the observed drought trends quantified using the Standardized Precipitation Evapotranspiration Index (SPEI. We found that the NDVI values recorded during the period of maximum vegetation activity (NDVImax predominantly showed a positive evolution in the majority of the semiarid regions assessed, but NDVImax was highly correlated with drought variability, and the trends of drought events influenced trends in NDVImax at the global scale. The semiarid regions that showed most increase in NDVImax (the Sahel, northern Australia, South Africa were characterized by a clear positive trend in the SPEI values, indicative of conditions of greater humidity and lesser drought conditions. While changes in drought severity may be an important driver of NDVI trends and land degradation processes in semiarid regions worldwide, drought did not apparently explain some of the observed changes in NDVImax. This reflects the complexity of vegetation activity processes in the world’s semiarid regions, and the difficulty of defining a universal response to drought in these regions, where a number of factors (natural and anthropogenic may also affect on land degradation.

  9. Drought-sensitive aquifer settings in southeastern Pennsylvania

    Science.gov (United States)

    Zimmerman, Tammy M.; Risser, Dennis W.

    2005-01-01

    This report describes the results of a study conducted by the U.S. Geological Survey, in cooperation with the Pennsylvania Department of Conservation and Natural Resources, Bureau of Topographic and Geologic Survey, to determine drought-sensitive aquifer settings in southeastern Pennsylvania. Because all or parts of southeastern Pennsylvania have been in drought-warning or drought-emergency status during 6 of the past 10 years from 1994 through 2004, this information should aid well owners, drillers, and water-resource managers in guiding appropriate well construction and sustainable use of Pennsylvania's water resources. 'Drought-sensitive' aquifer settings are defined for this study as areas unable to supply adequate quantities of water to wells during drought. Using information from previous investigations and a knowledge of the hydrogeology and topography of the study area, drought-sensitive aquifer settings in southeastern Pennsylvania were hypothesized as being associated with two factors - a water-table decline (WTD) index and topographic setting. The WTD index is an estimate of the theoretical water-table decline at the ground-water divide for a hypothetical aquifer with idealized geometry. The index shows the magnitude of ground-water decline after cessation of recharge is a function of (1) distance from stream to divide, (2) ground-water recharge rate, (3) transmissivity, (4) specific yield, and (5) duration of the drought. WTD indices were developed for 39 aquifers that were subsequently grouped into categories of high, moderate, and low WTD index. Drought-sensitive settings determined from the hypothesized factors were compared to locations of wells known to have been affected (gone dry, replaced, or deepened) during recent droughts. Information collected from well owners, drillers, and public agencies identified 2,016 wells affected by drought during 1998-2002. Most of the available data on the location of drought-affected wells in the study area were

  10. Standardized Water Budget Index and Validation in Drought Estimation of Haihe River Basin, North China

    Directory of Open Access Journals (Sweden)

    Shaohua Liu

    2016-01-01

    Full Text Available The physical-based drought indices such as the self-calibrated Palmer Drought Severity Index (sc-PDSI with the fixed time scale is inadequate for the multiscalar drought assessment, and the multiscalar drought indices including Standardized Precipitation Index (SPI, Reconnaissance Drought Index (RDI, and Standardized Precipitation Evapotranspiration Index (SPEI based on the meteorological factors are lack of physical mechanism and cannot depict the actual water budget. To fill this gap, the Standardized Water Budget Index (SWBI is constructed based on the difference between areal precipitation and actual evapotranspiration (AET, which can describe the actual water budget but also assess the drought at multiple time scales. Then, sc-PDSI was taken as the reference drought index to compare with multiscalar drought indices at different time scale in Haihe River basin. The result shows that SWBI correlates better with sc-PDSI and the RMSE of SWBI is less than other multiscalar drought indices. In addition, all of drought indices show a decreasing trend in Haihe River Basin, possibly due to the decreasing precipitation from 1961 to 2010. The decreasing trends of SWBI were significant and consistent at all the time scales, while the decreasing trends of other multiscalar drought indices are insignificant at time scale less than 3 months.

  11. Characteristics of meteorological drought pattern and risk analysis for maize production in Xinjiang, Northwest China

    Science.gov (United States)

    Li, Cheng; Wang, Ranghui; Ning, Husen; Luo, Qinghong

    2017-08-01

    Xinjiang is an important maize cultivation area in Northwest China. Investigating the relationship between meteorological drought and climate-driven maize yield can help to mitigate the negative impacts of drought on agricultural production in Xinjiang. In this study, multi-source data, including meteorological, agricultural, and socio-economic data, are collected to analyze the spatiotemporal patterns of drought and assess drought disaster risk. The standardized precipitation evapotranspiration index is calculated to classify different drought grades in the study area. The main results are as follows: (1) the relationship between drought and climate-driven maize yield is determined using a stepwise regression analysis, which indicates that drought conditions occurring from May to July are crucial for the yield in Xinjiang; (2) the modified Mann-Kendall test detects that the frequency-intensity-coverage of drought from May to July shows a decreasing tendency as a whole in the study area; (3) the correlation analysis shows that the multivariate ENSO index may be the dominant force in regional drought evolution; and (4) a drought disaster risk assessment system is constructed based on principles of natural disaster management. The drought disaster risk is higher in southwestern and northwestern Xinjiang, areas that should deserve more attention.

  12. All-photonic quantum repeaters

    Science.gov (United States)

    Azuma, Koji; Tamaki, Kiyoshi; Lo, Hoi-Kwong

    2015-01-01

    Quantum communication holds promise for unconditionally secure transmission of secret messages and faithful transfer of unknown quantum states. Photons appear to be the medium of choice for quantum communication. Owing to photon losses, robust quantum communication over long lossy channels requires quantum repeaters. It is widely believed that a necessary and highly demanding requirement for quantum repeaters is the existence of matter quantum memories. Here we show that such a requirement is, in fact, unnecessary by introducing the concept of all-photonic quantum repeaters based on flying qubits. In particular, we present a protocol based on photonic cluster-state machine guns and a loss-tolerant measurement equipped with local high-speed active feedforwards. We show that, with such all-photonic quantum repeaters, the communication efficiency scales polynomially with the channel distance. Our result paves a new route towards quantum repeaters with efficient single-photon sources rather than matter quantum memories. PMID:25873153

  13. Functional traits predict drought performance and distribution of Mediterranean woody species

    Science.gov (United States)

    Lopez-Iglesias, Bárbara; Villar, Rafael; Poorter, Lourens

    2014-04-01

    Water availability is one of the key environmental factors that affect plant establishment and distribution. In many regions water availability will decline with climate change, exposing small seedlings to a greater likelihood of drought. In this study, 17 leaves, stem, root, and whole-plant traits of ten woody Mediterranean species were measured under favourable growing conditions and seedling drought survival was evaluated during a simulated dry-down episode. The aims of this study were: i) to assess drought survival of different species, ii) to analyse which functional traits predict drought survival time, and iii) to explain species distribution in the field, based on species drought survival and drought strategies. Drought survival time varied ten-fold across species, from 19 to 192 days. Across species, drought survival was positively related to the rooting depth per leaf area, i.e., the ability to acquire water from deeper soil layers while reducing transpiring leaf area. Drought survival time was negatively related to species ability to grow quickly, as indicated by high relative growth and net assimilation rates. Drought survival also explained species distribution in the field. It was found that species were sorted along a continuum, ranging between two contrasting species functional extremes based on functional traits and drought performance. One extreme consisted of acquisitive fast-growing deciduous species, with thin, soft metabolically active leaves, with high resource use and vulnerability to drought. The opposite extreme consisted of conservative slow-growing evergreen species with sclerophyllous leaves, deep roots, a low transpiring area, and low water use, resulting in high drought survival and drought tolerance. The results show that these drought strategies shape species distribution in this Mediterranean area.

  14. Vegetation Drought Response Index: 2010-Present

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — VegDRI, short for Vegetation Drought Response Index, is a drought-monitoring tool developed by scientists at EROS in collaboration with the National Drought...

  15. Spatial-temporal dynamics of agricultural drought in the tallgrass prairie region of the Southern Great Plains during 2000-2013

    Science.gov (United States)

    Zhou, Y.; Xiao, X.; Zhang, G.; Bajgain, R.; Dong, J.; Qin, Y.; Jin, C.; Wagle, P.; Basara, J. B.; McCarthy, H. R.; Anderson, M. C.; Hain, C.; Otkin, J.

    2015-12-01

    Tallgrass prairie is an important ecosystem type and a major feed for beef cattle in the Southern Great Plains (SGP: Kansas, Oklahoma, and Texas). Frequent drought in the SGP affects the production of tallgrass prairie and ultimately the beef cattle production. It is, therefore, necessary to map drought vulnerable areas to help ranchers adapt cattle industry to drought conditions. In this study, we analyzed Land Surface Water Index (LSWI) calculated from near infrared and shortwave infrared bands of Moderate Resolution Imaging Spectroradiometer (MODIS) and quantified the spatial-temporal dynamics of agricultural drought in the tallgrass prairie region of the SGP during 2000-2013. The number of days with LSWI 5 °C) was defined as the duration of drought to generate drought duration maps for each year. Following the decreasing rainfall gradient from east to west in the SGP, counties in the west experienced whole growing season drought (WGSZ) more (three or more out of 14 years with WGSD), middle counties had one to two months summer drought, and eastern counties experienced less drought (mainly one year with WGSD and less than one month of summer drought). The LSWI-based drought duration map showed similar patterns with Evaporative Stress Index (ESI) and U.S. Drought Monitor (USDM) in wet, summer drought, and whole growing season drought years. Our drought map has identified the vulnerability of counties to different droughts (summer drought and whole growing season drought) in the SGP. This finer resolution (500 m) drought map has the potential to show the drought condition for individual ranch, which can be used to guide drought mitigation activities and livestock production.

  16. Legacy effects of drought on plant growth and the soil food web

    DEFF Research Database (Denmark)

    de Vries, Franciska; Liiri, Mira; Strandmark, Lisa Bjørnlund

    2012-01-01

    the potential to feed back on each other's performance. In a greenhouse experiment, we compared legacy effects of repeated drought on plant growth and the soil food web in two contrasting land-use systems: extensively managed grassland, rich in C and with a fungal-based food web, and intensively managed wheat...... lower in C and with a bacterial-based food web. Moreover, we assessed the effect of plant presence on the recovery of the soil food web after drought. Drought legacy effects increased plant growth in both systems, and a plant strongly reduced N leaching. Fungi, bacteria, and their predators were more...... resilient after drought in the grassland soil than in the wheat soil. The presence of a plant strongly affected the composition of the soil food web, and alleviated the effects of drought for most trophic groups, regardless of the system. This effect was stronger for the bottom trophic levels, whose...

  17. Molecular cloning and characterization of a gene encoding RING zinc finger ankyrin protein from drought-tolerant Artemisia desertorum

    Indian Academy of Sciences (India)

    Xiuhong Yang; Chao Sun; Yuanlei Hun; Zhongping Lin

    2008-03-01

    A RING zinc finger ankyrin protein gene, designated AdZFP1, was isolated from drought-tolerant Artemisia desertorum Spreng by mRNA differential display and RACE. Its cDNA was 1723 bp and encoded a putative protein of 445 amino acids with a predicted molecular mass of 47.9 kDa and an isoelectric point (pI) of 7.49. A typical C3HC4-type RING finger domain was found at the C-terminal region of the AdZFP1 protein, and several groups of ankyrin repeats were found at the N-terminal region. Alignments of amino acid sequence showed that AdZFP1 was 66% identical to the Arabidopsis thaliana putative RING zinc finger ankyrin protein AAN31869. Transcriptional analysis showed that AdZFP1 was inducible under drought stress in root, stem and leaf of the plant. Semi-quantitative reverse-transcriptase-polymerase chain reaction (RT-PCR) analysis showed that the transcript of AdZFP1 was strongly induced by exogenous abscisic acid (ABA) and also by salinity, cold and heat to some extent. Overexpression of the AdZFP1 gene in transgenic tobacco enhanced their tolerance to drought stress.

  18. Groundwater as an emergency source for drought mitigation in the Crocodile River catchment, South Africa

    Directory of Open Access Journals (Sweden)

    F. E. F. Mussá

    2014-03-01

    and environmental damages to the society. In this study, we assess the drought intensity and severity and the groundwater potential to be used as a supplement source of water to mitigate drought impacts in the Crocodile River catchment, a water-stressed sub-catchment of the Incomati River catchment in South Africa. The research methodology consists mainly of three parts. First, the spatial and temporal variation of the meteorological and hydrological drought severity and intensity over the catchment were evaluated. The Standardized Precipitation Index (SPI was used to analyse the meteorological drought and the Standardized Runoff Index (SRI was used for the hydrological drought. Second, the water deficit in the catchment during the drought period was computed using a simple water balance method. Finally, a groundwater model was constructed in order to assess the feasibility of using groundwater as an emergency source for drought impact mitigation. Results show that the meteorological drought severity varies accordingly with the precipitation; the low rainfall areas are more vulnerable to severe meteorological droughts (lower and upper crocodile. Moreover, the most water stressed sub-catchments with high level of water uses but limited storage, such as the Kaap located in the middle catchment and the Lower Crocodile sub-catchments are those which are more vulnerable to severe hydrological droughts. The analysis of the potential groundwater use during droughts showed that a deficit of 97 Mm3 yr−1 could be supplied from groundwater without considerable adverse impacts on the river base flow and groundwater storage. Abstraction simulations for different scenarios of extremely severe droughts reveal that it is possible to use groundwater to cope with the droughts in the catchment. However, local groundwater exploitation in Nelspruit and White River sub-catchment will cause large drawdowns (> 10 m and high base flow reduction (> 20%. This case study shows that

  19. Opposite metabolic responses of shoots and roots to drought

    Science.gov (United States)

    Gargallo-Garriga, Albert; Sardans, Jordi; Pérez-Trujillo, Míriam; Rivas-Ubach, Albert; Oravec, Michal; Vecerova, Kristyna; Urban, Otmar; Jentsch, Anke; Kreyling, Juergen; Beierkuhnlein, Carl; Parella, Teodor; Peñuelas, Josep

    2014-10-01

    Shoots and roots are autotrophic and heterotrophic organs of plants with different physiological functions. Do they have different metabolomes? Do their metabolisms respond differently to environmental changes such as drought? We used metabolomics and elemental analyses to answer these questions. First, we show that shoots and roots have different metabolomes and nutrient and elemental stoichiometries. Second, we show that the shoot metabolome is much more variable among species and seasons than is the root metabolome. Third, we show that the metabolic response of shoots to drought contrasts with that of roots; shoots decrease their growth metabolism (lower concentrations of sugars, amino acids, nucleosides, N, P, and K), and roots increase it in a mirrored response. Shoots are metabolically deactivated during drought to reduce the consumption of water and nutrients, whereas roots are metabolically activated to enhance the uptake of water and nutrients, together buffering the effects of drought, at least at the short term.

  20. Do land surface models need to include differential plant species responses to drought? Examining model predictions across a mesic-xeric gradient in Europe

    OpenAIRE

    M. G. De Kauwe; Zhou, S.-X.; B. E. Medlyn; A. J. Pitman; Wang, Y.-P.; R. A. Duursma; I. C. Prentice

    2015-01-01

    Future climate change has the potential to increase drought in many regions of the globe, making it essential that land surface models (LSMs) used in coupled climate models realistically capture the drought responses of vegetation. Recent data syntheses show that drought sensitivity varies considerably among plants from different climate zones, but state-of-the-art LSMs currently assume the same drought sensitivity for all vegetation. We tested whether variable drought sensi...

  1. Comparison of drought occurrence in selected Slovak and Czech catchments

    Science.gov (United States)

    Fendekova, Miriam; Fendek, Marian; Porubska, Diana; Hanel, Martin; Horacek, Stanislav; Martinkova, Marta; Vizina, Adam

    2014-05-01

    the discharges were re-calculated into specific discharge and base flow. The results showed that drought occurrence in evaluated Czech and Slovak catchment reflects very variable physical conditions in catchments, first of all the location of the catchment (latitude and altitude). The latitude difference reflects itself in starting time of drought which often propagates from the west to the east. The altitude is reflected in the seasonal pattern of drought, where drought in higher altitudes occurs much often in winter-spring period whereas in lower altitudes the summer-autumn droughts prevail. Total number of droughts with duration of more than 50 days was much higher in Slovak than in Czech catchments, which could reflect the more continental character of climate in Slovakia. Drought occurrence in Žitava catchment often followed the drought in Czech catchments; especially the drought in Teplá. On the other hand, drought occurrence in the Metuje catchment was in some cases closer to drought development in Slovakia than in other two Czech catchments. The longest drought in discharges, estimated for Rakovnický potok by the method of SPA lasting for 1569 days in 2006 - 2010 period was caused probably by the human activities, because in none of other evaluated catchments such a long drought in the same or similar period occurred. Acknowledgments The research was done and results were published with the financial contribution of project No. APVV-0089-12 as well as projects No. 7AMB12SK167 and APVV-SK-CZ-0156-11 financed by the Ministry of Education of the Czech Republic and APVV agency of the Slovak Republic.

  2. Socioeconomic Drought in a Changing Climate: Modeling and Management

    Science.gov (United States)

    AghaKouchak, Amir; Mehran, Ali; Mazdiyasni, Omid

    2016-04-01

    Drought is typically defined based on meteorological, hydrological and land surface conditions. However, in many parts of the world, anthropogenic changes and water management practices have significantly altered local water availability. Socioeconomic drought refers to conditions whereby the available water supply cannot satisfy the human and environmental water needs. Surface water reservoirs provide resilience against local climate variability (e.g., droughts), and play a major role in regional water management. This presentation focuses on a framework for describing socioeconomic drought based on both water supply and demand information. We present a multivariate approach as a measure of socioeconomic drought, termed Multivariate Standardized Reliability and Resilience Index (MSRRI; Mehran et al., 2015). This model links the information on inflow and surface reservoir storage to water demand. MSRRI integrates a "top-down" and a "bottom-up" approach for describing socioeconomic drought. The "top-down" component describes processes that cannot be simply controlled or altered by local decision-makers and managers (e.g., precipitation, climate variability, climate change), whereas the "bottom-up" component focuses on the local resilience, and societal capacity to respond to droughts. The two components (termed, Inflow-Demand Reliability (IDR) indicator and Water Storage Resilience (WSR) indicator) are integrated using a nonparametric multivariate approach. We use this framework to assess the socioeconomic drought during the Australian Millennium Drought (1998-2010) and the 2011-2014 California Droughts. MSRRI provides additional information on socioeconomic drought onset, development and termination based on local resilience and human demand that cannot be obtained from the commonly used drought indicators. We show that MSRRI can be used for water management scenario analysis (e.g., local water availability based on different human water demands scenarios). Finally

  3. Probabilistic analysis of hydrological drought characteristics using meteorological drought

    NARCIS (Netherlands)

    Wong, G.; Lanen, van H.A.J.; Torfs, P.J.J.F.

    2013-01-01

    Droughts are an inevitable consequence of climate variability and are pervasive across many regions. Their effects can vary on an extensive scale, depending on the type of drought and people’s vulnerability. Crucial characteristics of both hydrological (groundwater, streamflow) and meteorological (p

  4. Drought in groundwater-drought distribution and performance indicators

    NARCIS (Netherlands)

    Peters, E.; Lanen, van H.A.J.; Torfs, P.J.J.F.; Bier, G.

    2005-01-01

    In order to investigate how droughts are changed by the groundwater system and to analyse the performance of groundwater during drought, 10 time series of 1000 years of recharge and groundwater discharge were generated. The 10×1000 years of synthetic daily data were generated using Nearest Neighbour

  5. Probabilistic analysis of hydrological drought characteristics using meteorological drought

    NARCIS (Netherlands)

    Wong, G.; Lanen, van H.A.J.; Torfs, P.J.J.F.

    2013-01-01

    Droughts are an inevitable consequence of climate variability and are pervasive across many regions. Their effects can vary on an extensive scale, depending on the type of drought and people’s vulnerability. Crucial characteristics of both hydrological (groundwater, streamflow) and meteorological

  6. Geomorphic response to historic drought in northern California

    Science.gov (United States)

    Bennett, Georgina; Roering, Joshua; Mackey, Ben; Handwerger, Alexander; Guillod, Benoit; Schmidt, David

    2016-04-01

    California declared a state of drought emergency in early 2014 with a recent study showing that 2012 - 2015 constitutes a drought unprecedented in the state's historical record. Much has been reported on the drought's devastating impacts on water supply, agriculture and wildfire occurrence as well as its possible origins, including the role of anthropogenic climate change. However, its geomorphic impact has been given little attention. We address this gap by assessing the response of earthflows to drought in the Eel River in northern California. Despite their slow-moving nature, earthflows contribute ~50% of erosion in the region and are a constant threat to transport routes, making their behavior important to understand. We used pixel tracking in the program COSI CORR to measure velocities of 98 earthflows for the periods 2009 - 2012 and 2012 - 2015 from 0.5 m resolution Worldview satellite imagery. Putting these measurements in the context of velocities manually measured from aerial photographs dating back to the 1950s indicates that whilst earthflows have decelerated significantly in the ensuing drought this is part of a slowing trend commencing around 2000. We show that decadal earthflow velocities are closely correlated with the Palmer Drought Severity Index (PDSI), which in turn is correlated with North American Land Data Assimilation System (NLDAS)-modeled soil moisture. Slowing of earthflows since 2000 is coincident with a reduction of soil moisture, starting with the 2000 - 2001 drought from which earthflows have not yet returned to their pre-drought values and which set the stage for the slowest mean velocities observed in recent decades during the current drought. It will be important to continue to monitor these earthflows as rains return, particularly given the hypothesis that extreme drying may increase pathways for future runoff into earthflows.

  7. Activated Expression of WRKY57 Confers Drought Tolerance in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Yanjuan Jiang; Gang Liang; Diqiu Yu

    2012-01-01

    Drought is one of the most serious environmental factors that limit the productivity of agricultural crops worldwide.However,the mechanism underlying drought tolerance in plants is unclear.WRKY transcription factors are known to function in adaptation to abiotic stresses.By screening a pool of WRKY-associated T-DNA insertion mutants,we isolated a gain-of-function mutant,acquired drought tolerance (adt),showing improved drought tolerance.Under drought stress conditions,adt accumulated higher levels of ABA than wild-type plants.Stomatal aperture analysis indicated that adt was more sensitive to ABA than wild-type plants.Molecular genetic analysis revealed that a T-DNA insertion in adt led to activated expression of a WRKY gene that encodes the WRKR57 protein.Constitutive expression of WRKY57 also conferred similar drought tolerance.Consistently with the high ABA content and enhanced drought tolerance,three stress-responsive genes (RD29A,NCED3,and ABA3) were up-regulated in adt.ChIP assays demonstrated that WRKY57 can directly bind the W-box of RD29A and NCED3 promoter sequences.In addition,during ABA treatment,seed germination and early seedling growth of adt were inhibited,whereas,under high osmotic conditions,adt showed a higher seed germination frequency.In summary,our results suggested that the activated expression of WRKY57 improved drought tolerance of Arabidopsis by elevation of ABA levels.Establishment of the functions of WRKY57 will enable improvement of plant drought tolerance through gene manipulation approaches.

  8. Drought: A comprehensive R package for drought monitoring, prediction and analysis

    Science.gov (United States)

    Hao, Zengchao; Hao, Fanghua; Singh, Vijay P.; Cheng, Hongguang

    2015-04-01

    Drought may impose serious challenges to human societies and ecosystems. Due to complicated causing effects and wide impacts, a universally accepted definition of drought does not exist. The drought indicator is commonly used to characterize drought properties such as duration or severity. Various drought indicators have been developed in the past few decades for the monitoring of a certain aspect of drought condition along with the development of multivariate drought indices for drought characterizations from multiple sources or hydro-climatic variables. Reliable drought prediction with suitable drought indicators is critical to the drought preparedness plan to reduce potential drought impacts. In addition, drought analysis to quantify the risk of drought properties would provide useful information for operation drought managements. The drought monitoring, prediction and risk analysis are important components in drought modeling and assessments. In this study, a comprehensive R package "drought" is developed to aid the drought monitoring, prediction and risk analysis (available from R-Forge and CRAN soon). The computation of a suite of univariate and multivariate drought indices that integrate drought information from various sources such as precipitation, temperature, soil moisture, and runoff is available in the drought monitoring component in the package. The drought prediction/forecasting component consists of statistical drought predictions to enhance the drought early warning for decision makings. Analysis of drought properties such as duration and severity is also provided in this package for drought risk assessments. Based on this package, a drought monitoring and prediction/forecasting system is under development as a decision supporting tool. The package will be provided freely to the public to aid the drought modeling and assessment for researchers and practitioners.

  9. A European Drought Reference Database: Design and Online Implementation

    NARCIS (Netherlands)

    Stagge, J.H.; Tallaksen, L.M.; Kohn, I.; Stahl, K.; Loon, van A.

    2013-01-01

    This report presents the structure and status of the online European Drought Reference (EDR) database. This website provides detailed historical information regarding major historical European drought events. Each drought event is summarized using climatological drought indices, hydrological drought

  10. Spatial and temporal variability of precipitation and drought in Portugal

    Directory of Open Access Journals (Sweden)

    D. S. Martins

    2012-05-01

    Full Text Available The spatial variability of precipitation and drought are investigated for Portugal using monthly precipitation from 74 stations and minimum and maximum temperature from 27 stations, covering the common period of 1941–2006. Seasonal precipitation and the corresponding percentages in the year, as well as the precipitation concentration index (PCI, was computed for all 74 stations and then used as an input matrix for an R-mode principal component analysis to identify the precipitation patterns. The standardized precipitation index at 3 and 12 month time scales were computed for all stations, whereas the Palmer Drought Severity Index (PDSI and the modified PDSI for Mediterranean conditions (MedPDSI were computed for the stations with temperature data. The spatial patterns of drought over Portugal were identified by applying the S-mode principal component analysis coupled with varimax rotation to the drought indices matrices. The result revealed two distinct sub-regions in the country relative to both precipitation regimes and drought variability. The analysis of time variability of the PC scores of all drought indices allowed verifying that there is no linear trend indicating drought aggravation or decrease. In addition, the analysis shows that results for SPI-3, SPI-12, PDSI and MedPDSI are coherent among them.

  11. Transcriptomic basis for drought-resistance in Brassica napus L.

    Science.gov (United States)

    Wang, Pei; Yang, Cuiling; Chen, Hao; Song, Chunpeng; Zhang, Xiao; Wang, Daojie

    2017-01-01

    Based on transcriptomic data from four experimental settings with drought-resistant and drought-sensitive cultivars under drought and well-watered conditions, statistical analysis revealed three categories encompassing 169 highly differentially expressed genes (DEGs) in response to drought in Brassica napus L., including 37 drought-resistant cultivar-related genes, 35 drought-sensitive cultivar-related genes and 97 cultivar non-specific ones. We provide evidence that the identified DEGs were fairly uniformly distributed on different chromosomes and their expression patterns are variety specific. Except commonly enriched in response to various stimuli or stresses, different categories of DEGs show specific enrichment in certain biological processes or pathways, which indicated the possibility of functional differences among the three categories. Network analysis revealed relationships among the 169 DEGs, annotated biological processes and pathways. The 169 DEGs can be classified into different functional categories via preferred pathways or biological processes. Some pathways might simultaneously involve a large number of shared DEGs, and these pathways are likely to cross-talk and have overlapping biological functions. Several members of the identified DEGs fit to drought stress signal transduction pathway in Arabidopsis thaliana. Finally, quantitative real-time PCR validations confirmed the reproducibility of the RNA-seq data. These investigations are profitable for the improvement of crop varieties through transgenic engineering. PMID:28091614

  12. Drought variability and change across the Iberian Peninsula

    Science.gov (United States)

    Coll, J. R.; Aguilar, E.; Ashcroft, L.

    2016-09-01

    Drought variability and change was assessed across the Iberian Peninsula over more than 100 years expanding through the twentieth century and the first decade of the twenty-first century. Daily temperature and precipitation data from 24 Iberian time series were quality controlled and homogenized to create the Monthly Iberian Temperature and Precipitation Series (MITPS) for the period 1906-2010. The Standardized Precipitation Index (SPI), driven only by precipitation, and the Standardized Precipitation Evapotranspiration Index (SPEI), based on the difference between the precipitation and the reference evapotranspiration (ET0), were computed at annual and seasonal scale to describe the evolution of droughts across time. The results confirmed that a clear temperature increase has occurred over the entire Iberian Peninsula at the annual and seasonal scale, but no significant changes in precipitation accumulated amounts were found. Similar drought variability was provided by the SPI and SPEI, although the SPEI showed greater drought severity and larger surface area affected by drought than SPI from 1980s to 2010 due to the increase in atmospheric evaporative demand caused by increased temperatures. Moreover, a clear drying trend was found by the SPEI for most of the Iberian Peninsula at annual scale and also for spring and summer, although the SPI did not experience significant changes in drought conditions. From the drying trend identified for most of the Iberian Peninsula along the twentieth century, an increase in drought conditions can also be expected for this region in the twenty-first century according to future climate change projections and scenarios.

  13. Aerosol forcing of extreme summer drought over North China

    Science.gov (United States)

    Zhang, Lixia; Wu, Peili; Zhou, Tianjun

    2017-03-01

    The frequency of extreme summer drought has been increasing in North China during the past sixty years, which has caused serious water shortages. It remains unclear whether anthropogenic forcing has contributed to the increasing extreme droughts. Using the National Centers for Environmental Prediction and the National Center for Atmospheric Research (NCEP/NCAR) re-analysis data and Coupled Model Intercomparison Project Phase 5 (CMIP5) model simulations with various combinations of historical forcings, the authors investigated the driving mechanism behind the observed changes. Metrological drought is usually measured by precipitation anomalies, which show lower fidelity in current climate models compared to large-scale circulation patterns. Based on NCEP/NCAR re-analysis, a linear relationship is firstly established between the weakest regional average 850 hPa southerly winds and extreme summer drought. This meridional winds index (MWI) is then used as a proxy for attribution of extreme North China drought using CMIP5 outputs. Examination of the CMIP5 simulations reveals that the probability of the extreme summer droughts with the first percentile of MWI for 1850–2004 under anthropogenic forcing has increased by 100%, on average, relative to a pre-industrial control run. The more frequent occurrence of extremely weak MWIs or drought over North China is ascribed from weakened climate and East Asian summer monsoon (EASM) circulation due to the direct cooling effect from increased aerosol.

  14. Carbon Dynamics of Pinus palustris Ecosystems Following Drought

    Directory of Open Access Journals (Sweden)

    Gregory Starr

    2016-04-01

    Full Text Available Drought can affect forest structure and function at various spatial and temporal scales. Forest response and recovery from drought may be a result of position within landscape. Longleaf pine forests in the United States have been observed to reduce their carbon sequestration capacity during drought. We collected eddy covariance data at the ends of an edaphic longleaf pine gradient (xeric and mesic sites over seven years; two years of normal rainfall were followed by 2.5 years of drought, then 2.5 years of normal or slightly above-average rainfall. Drought played a significant role in reducing the physiological capacity of the sites and was compounded when prescribed fire occurred during the same periods. The mesic site has a 40% greater basal area then the xeric site, which accounts for its larger sequestration capacity; however, both sites show the same range of variance in fluxes over the course of the study. Following drought, both sites became carbon sinks. However, the xeric site had a longer carry-over effect and never returned to pre-drought function. Although this study encompassed seven years, we argue that longer studies with greater spatial variance must be undertaken to develop a more comprehensive understanding of forest response to changing climate.

  15. Regional Landsat-Based Drought Monitoring from 1982 to 2014

    Directory of Open Access Journals (Sweden)

    Faour Ghaleb

    2015-08-01

    Full Text Available Drought is a serious natural hazard with far-reaching impacts including soil damages, economic losses, and threatening the livelihood and health of local residents. The goal of the present work was to monitor the vegetation health across Lebanon in 2014 using remote sensing techniques. Landsat images datasets, with a spatial resolution of 30 m and from different platforms, were used to identify the VCI (Vegetation Condition Index and TCI (Temperature Condition Index. The VCI was based on the Normalized Difference Vegetation Index (NDVI datasets. The TCI used land surface temperature (LST datasets. As a result, the VHI (Vegetation Health Index was produced and classified into five categories: extreme, severe, moderate, mild, and no drought. The results show practically no extreme drought (~0.27 km2 in the vegetated area in Lebanon during 2014. Moderate to severe drought mainly occurred in the north of Lebanon (i.e., the Amioun region and the plain of Akkar. The Tyr region and the Bekaa valley experienced a low level of drought (mild drought. This approach allows decision makers to monitor, investigate and resolve drought conditions more effectively.

  16. Transcriptomic basis for drought-resistance in Brassica napus L.

    Science.gov (United States)

    Wang, Pei; Yang, Cuiling; Chen, Hao; Song, Chunpeng; Zhang, Xiao; Wang, Daojie

    2017-01-01

    Based on transcriptomic data from four experimental settings with drought-resistant and drought-sensitive cultivars under drought and well-watered conditions, statistical analysis revealed three categories encompassing 169 highly differentially expressed genes (DEGs) in response to drought in Brassica napus L., including 37 drought-resistant cultivar-related genes, 35 drought-sensitive cultivar-related genes and 97 cultivar non-specific ones. We provide evidence that the identified DEGs were fairly uniformly distributed on different chromosomes and their expression patterns are variety specific. Except commonly enriched in response to various stimuli or stresses, different categories of DEGs show specific enrichment in certain biological processes or pathways, which indicated the possibility of functional differences among the three categories. Network analysis revealed relationships among the 169 DEGs, annotated biological processes and pathways. The 169 DEGs can be classified into different functional categories via preferred pathways or biological processes. Some pathways might simultaneously involve a large number of shared DEGs, and these pathways are likely to cross-talk and have overlapping biological functions. Several members of the identified DEGs fit to drought stress signal transduction pathway in Arabidopsis thaliana. Finally, quantitative real-time PCR validations confirmed the reproducibility of the RNA-seq data. These investigations are profitable for the improvement of crop varieties through transgenic engineering.

  17. Comparison between remote-sensing-based drought indices in East Java

    Science.gov (United States)

    Febrina Amalo, Luisa; Hidayat, Rahmat; Haris

    2017-01-01

    Drought is natural hazard which has causing several impacts, such as decreasing of air and water quality, land degradation, forest fire, decreasing of agricultural crops production. Drought assessment using drought indices have widely conducted for drought monitoring. Remote-sensing-based indices defined as an index which using remote sensing data for mapping the drought condition in particular area or region. This research aims to compare remote-sensing-based drought indices, namely TCI, VCI and VHI to obtain a better understanding about the differentiation between each index, and their application for monitoring drought in East Java on El Nino year 2015. LST and EVI data were used to construct the indices. The result showed, each index proved to be useful, quick, sufficient and inexpensive tool for drought monitoring. However, each index has its differences. TCI proved to be detected drought sensitively in dry season or months when high temperature occurred. While VCI detected drought more sensitive in wet season as well (December-January-February to May) than TCI and VHI. Meanwhile, VHI which the enhancement of TCI and VHI has combined two indicators to provide better comprehension about drought occurrence.

  18. National-scale analysis of simulated hydrological droughts (1891-2015)

    Science.gov (United States)

    Rudd, Alison C.; Bell, Victoria A.; Kay, Alison L.

    2017-07-01

    Droughts are phenomena that affect people and ecosystems in a variety of ways. One way to help with resilience to future droughts is to understand the characteristics of historic droughts and how these have changed over the recent past. Although, on average, Great Britain experiences a relatively wet climate it is also prone to periods of low rainfall which can lead to droughts. Until recently research into droughts of Great Britain has been neglected compared to other natural hazards such as storms and floods. This study is the first to use a national-scale gridded hydrological model to characterise droughts across Great Britain over the last century. Firstly, the model performance at low flows is assessed and it is found that the model can simulate low flows well in many catchments across Great Britain. Next, the threshold level method is applied to time series of monthly mean river flow and soil moisture to identify historic droughts (1891-2015). It is shown that the national-scale gridded output can be used to identify historic drought periods. A quantitative assessment of drought characteristics shows that groundwater-dependent areas typically experience more severe droughts, which have longer durations rather than higher intensities. There is substantial spatial and temporal variability in the drought characteristics, but there are no consistent changes through time.

  19. Multiyear drought-induced morbidity preceding tree death in southeastern U.S. forests.

    Science.gov (United States)

    Berdanier, Aaron B; Clark, James S

    2016-01-01

    Recent forest diebacks, combined with threats of future drought, focus attention on the extent to which tree death is caused by catastrophic events as opposed to chronic declines in health that accumulate over years. While recent attention has focused on large-scale diebacks, there is concern that increasing drought stress and chronic morbidity may have pervasive impacts on forest composition in many regions. Here we use long-term, whole-stand inventory data from southeastern U.S. forests to show that trees exposed to drought experience multiyear declines in growth prior to mortality. Following a severe, multiyear drought, 72% of trees that did not recover their pre-drought growth rates died within 10 yr. This pattern was mediated by local moisture availability. As an index of morbidity prior to death, we calculated the difference in cumulative growth after drought relative to surviving conspecifics. The strength of drought-induced morbidity varied among species and was correlated with drought tolerance. These findings support the ability of trees to avoid death during drought events but indicate shifts that could occur over decades. Tree mortality following drought is predictable in these ecosystems based on growth declines, highlighting an opportunity to address multiyear drought-induced morbidity in models, experiments, and management decisions.

  20. SPEI-Based Spatiotemporal Analysis of Drought in Haihe River Basin from 1961 to 2010

    Directory of Open Access Journals (Sweden)

    Meijian Yang

    2016-01-01

    Full Text Available Under the background of climate change, the monthly accumulated precipitation and monthly averaged temperature of 47 meteorological stations in and around Haihe River Basin (HRB were analyzed using Standardized Precipitation Evapotranspiration Indices (SPEI to obtain the temporal variability and spatial distribution of different drought levels during the last 50 years with the support of GIS. The results show that (1 from 1961 to 2010 the drought frequency and degree in annual and seasonal scale are rising and the affecting areas of all degrees of drought have a temporal variability of increasing trend. The ratios that the influencing area of drought, light drought, moderate drought, severe drought, and extreme drought account for the whole HRB area are increasing with gradients of 0.64%/a, 0.18%/a, 0.31%/a, 0.14%/a, and 0.01%/a, respectively, and (2 there is a climate break point which occurred in 1990; after the comparison of the drought happening probability between 1961 and 1990 and between 1991 and 2010, all degrees of drought occurrence probability have a remarkable rising trend, and the drought concentrating regions moved from the north HRB to the central HRB.

  1. Drought Characteristic Analysis Based on an Improved PDSI in the Wei River Basin of China

    Directory of Open Access Journals (Sweden)

    Lei Zou

    2017-03-01

    Full Text Available In this study, to improve the efficiency of the original Palmer Drought Severity Index (PDSI_original, we coupled the Soil and Water Assessment tool (SWAT and PDSI_original to construct a drought index called PDSI_SWAT. The constructed PDSI_SWAT is applied in the Wei River Basin (WRB of China during 1960–2012. The comparison of the PDSI_SWAT with four other commonly used drought indices reveals the effectiveness of the PDSI_SWAT in describing the drought propagation processes in WRB. The whole WRB exhibits a dry trend, with more significant trends in the northern, southeastern and western WRB than the remaining regions. Furthermore, the drought frequencies show that drought seems to occur more likely in the northern part than the southern part of WRB. The principle component analysis method based on the PDSI_SWAT reveals that the whole basin can be further divided into three distinct sub-regions with different drought variability, i.e., the northern, southeastern and western part. Additionally, these three sub-regions are also consistent with the spatial pattern of drought shown by the drought frequency. The wavelet transform analysis method indicates that the El Niño-Southern Oscillation (ENSO events have strong impacts on inducing droughts in the WRB. The results of this study could be beneficial for a scientific water resources management and drought assessment in the current study area and also provide a valuable reference for other areas with similar climatic characteristics.

  2. Intensity-Duration-Frequency and spatial analysis of droughts using the Standardized Precipitation Index

    Directory of Open Access Journals (Sweden)

    M. Mohseni Saravi

    2009-03-01

    Full Text Available Precipitation deficit and its daily, seasonal and annual oscillations are inherent characteristics of Iran's climate. Droughts are generally characterized by a prolonged and abnormal moisture deficiency. In drought studies it is important to characterize the start and end of a drought as well as its intensity, duration, frequency and magnitude. The objective of this study was to analyze drought characteristics and to develop drought maps in the Karoon river basin, Iran. The Standardized Precipitation Index (SPI was used in drought analysis based on the data for meteorological stations located inside or adjacent to the study area and three time scales including the 3-, 6- and 12-month SPI were evaluated. After determining the dry and wet periods, historical characteristics of droughts were identified and spatial distribution maps of droughts were plotted using GIS. Based on frequency distributions, drought durations and magnitudes were computed corresponding to 5, 10, 20, 50 and 100-year return periods. The Time scale-Duration-Frequency (TDF and Time scale-Magnitude-Frequency (TMF relationships were also developed, which constitute an essential tool for water resource design purposes. Drought spatial distribution maps show that extreme conditions dominate the southeastern regions of the basin. The efficiency of the SPI is determined by monitoring the drought of 1999.

  3. Assessing spatiotemporal variation of drought and its impact on maize yield in Northeast China

    Science.gov (United States)

    Guo, Enliang; Liu, Xingpeng; Zhang, Jiquan; Wang, Yongfang; Wang, Cailin; Wang, Rui; Li, Danjun

    2017-10-01

    In the context of global climate change, drought has become an important factor that affects the maize yield in China. To analyse the impact of drought on maize yield loss in Northeast China in current and future climate scenarios, the Composite Meteorological Drought Index (CI) is introduced to reconstruct the following drought indicators: drought accumulative days (DAD), drought accumulative intensity (DAI), and consecutive drought days (CDD). These three drought indicators are used to describe the three-dimensional characteristics of drought in this study. Sen's slope method and three-dimensional copula functions are adopted to analyse the variety of drought features, and Ensemble Empirical Mode Decomposition (EEMD) is used to analyse the variations in maize yield. A temporal assessment of the standardized yield residuals series (SYRS) of maize from 1961 to 2014 is conducted. A panel regression model is applied to demonstrate the drought impact on maize yield at various growth stages under the RCP4.5 scenario. The results show that the drought risk level for midwest Jilin Province, western Liaoning, and eastern Heilongjiang increase with global warming in the current scenario. The shorter three-dimensional joint return periods, 44-80 yr, were mainly located in western Jilin Province, Liaodong Peninsula, and northwestern Liaoning. Eastern Heilongjiang has a slightly longer joint return period of 80-100 yr. The SYRS shows a strong statistical correlation with drought indicator variations; drought-prone regions exhibit strong positive correlations. In comparison, excess precipitation regions show strong negative correlations with drought indicators in most growth stages. Drought indicators have a relatively strong association with SYRS at the milky-mature maize growth stage, and the occurrence of drought during this period primarily determines the maize yield changes in the future. Maize yield changes are -2.04%, -2.65% and -1.57% for Liaoning, Jilin, and

  4. Repeat-until-success quantum repeaters

    Science.gov (United States)

    Bruschi, David Edward; Barlow, Thomas M.; Razavi, Mohsen; Beige, Almut

    2014-09-01

    We propose a repeat-until-success protocol to improve the performance of probabilistic quantum repeaters. Conventionally, these rely on passive static linear-optics elements and photodetectors to perform Bell-state measurements (BSMs) with a maximum success rate of 50%. This is a strong impediment for entanglement swapping between distant quantum memories. Every time a BSM fails, entanglement needs to be redistributed between the corresponding memories in the repeater link. The key ingredients of our scheme are repeatable BSMs. Under ideal conditions, these turn probabilistic quantum repeaters into deterministic ones. Under realistic conditions, our protocol too might fail. However, using additional threshold detectors now allows us to improve the entanglement generation rate by almost orders of magnitude, at a nominal distance of 1000 km, compared to schemes that rely on conventional BSMs. This improvement is sufficient to make the performance of our scheme comparable to the expected performance of some deterministic quantum repeaters.

  5. Distinguishing drought and water scarcity

    NARCIS (Netherlands)

    Loon, van A.

    2013-01-01

    Water resources can become strained by both natural factors such as drought and human factors such as unsustainable use. Water resource managers can develop practices to reduce overuse of water resources, but they cannot prevent droughts, so distinguishing the causes of water stress can be useful.

  6. Soil microbiology under drought stress

    Science.gov (United States)

    he severity of the 2012 drought affecting much of the Midwestern U.S. is readily observed in the extremely stressed conditions of crops and natural vegetation. However, we may not realize that the extent of drought effects is just as severe on the biology below the soil surface. Detrimental effects ...

  7. Drought and ecosystem carbon cycling

    NARCIS (Netherlands)

    Molen, van der M.K.; Dolman, A.J.; Ciais, P.; Eglin, T.; Gobron, N.; Law, B.E.; Meir, P.; Peters, W.; Philips, O.L.; Hurk, van den B.J.J.M.; Jeu, M.; Kruijt, B.; Teuling, A.J.; Werf, van der G.R.; Wang, G.

    2011-01-01

    Drought as an intermittent disturbance of the water cycle interacts with the carbon cycle differently than the ‘gradual’ climate change. During drought plants respond physiologically and structurally to prevent excessive water loss according to species-specific water use strategies. This has consequ

  8. A data fusion-based drought index

    Science.gov (United States)

    Azmi, Mohammad; Rüdiger, Christoph; Walker, Jeffrey P.

    2016-03-01

    Drought and water stress monitoring plays an important role in the management of water resources, especially during periods of extreme climate conditions. Here, a data fusion-based drought index (DFDI) has been developed and analyzed for three different locations of varying land use and climate regimes in Australia. The proposed index comprehensively considers all types of drought through a selection of indices and proxies associated with each drought type. In deriving the proposed index, weekly data from three different data sources (OzFlux Network, Asia-Pacific Water Monitor, and MODIS-Terra satellite) were employed to first derive commonly used individual standardized drought indices (SDIs), which were then grouped using an advanced clustering method. Next, three different multivariate methods (principal component analysis, factor analysis, and independent component analysis) were utilized to aggregate the SDIs located within each group. For the two clusters in which the grouped SDIs best reflected the water availability and vegetation conditions, the variables were aggregated based on an averaging between the standardized first principal components of the different multivariate methods. Then, considering those two aggregated indices as well as the classifications of months (dry/wet months and active/non-active months), the proposed DFDI was developed. Finally, the symbolic regression method was used to derive mathematical equations for the proposed DFDI. The results presented here show that the proposed index has revealed new aspects in water stress monitoring which previous indices were not able to, by simultaneously considering both hydrometeorological and ecological concepts to define the real water stress of the study areas.

  9. Drought Occurrence and Management in Kazakhstan

    Science.gov (United States)

    Iskakov, Y.; Mendigarin, A.; Sazanova, B.; Zhumabayev, Y.

    2014-12-01

    A direct and reliable indicator of drought can be measured by the productive moisture content (PMC) in soil, which uses the weight of the moisture in a soil profile. However the limited network of PMC measurement sites in Kazakhstan (123 for the total area of 2. 7 million km2) does not allow a spatial assessment of drought conditions across the vast majority of the country. To assess the availability of soil moisture and the likelihood of drought, we calculated spatial structure of soil moisture deficit, using the Selyaninov Hydrothermal Coefficient (HTCs). It was derived for the vegetatively active period from May to August. Figure 1 shows the average structure of soil moisture availability across Kazakhstan, and indicates that most of the country is vulnerable to drought. In response to this vulnerability the Kazakhstan also established the following policies and technologies to mitigate the impact of drought. Those measures include: 1. Introduction of resource-saving (soil-protective and moisture preserving) No-Till technologies. 2. Structural and technological diversification of plant growing. 3. Introduction of efficient irrigation systems for southern Kazakhstan. 4. Adaptation of weather and field reports to optimize the benefits of agrotechnical activities. 5. Re-equipment of agricultural vehicles and machinery. 6. Training and professional development of specialists in agriculture. 7. Improvement of insurance system for plant growing. 8. Improvement of systems and mechanisms of state support for small and medium agricultural producers. 9. Improvement of the system of scientific and technological and innovative support for grain production. These strategies, how they are being implemented, and the targeted goals will be presented. We will provide findings from experimental field stations, and model farms. The goals is to improve efficiency in water resources, effectively communication relevant information to farmers, policy makers and the insurance industry

  10. Recent La Plata basin drought conditions observed by satellite gravimetry

    CERN Document Server

    Chen, J L; Tapley, B D; Longuevergne, L; Yang, Z L; Scanlon, B R; 10.1029/2010JD014689

    2010-01-01

    The Gravity Recovery and Climate Experiment (GRACE) provides quantitative measures of terrestrial water storage (TWS) change. GRACE data show a significant decrease in TWS in the lower (southern) La Plata river basin of South America over the period 2002-2009, consistent with recognized drought conditions in the region. GRACE data reveal a detailed picture of temporal and spatial evolution of this severe drought event, which suggests that the drought began in lower La Plata in around austral spring 2008 and then spread to the entire La Plata basin and peaked in austral fall 2009. During the peak, GRACE data show an average TWS deficit of ~12 cm (equivalent water layer thickness) below the 7 year mean, in a broad region in lower La Plata. GRACE measurements are consistent with accumulated precipitation data from satellite remote sensing and with vegetation index changes derived from Terra satellite observations. The Global Land Data Assimilation System model captures the drought event but underestimates its in...

  11. Comparative analysis of expressed sequence tags (ESTs) between drought-tolerant and -susceptible genotypes of chickpea under terminal drought stress

    Science.gov (United States)

    2011-01-01

    Background Chickpea (Cicer arietinum L.) is an important grain-legume crop that is mainly grown in rainfed areas, where terminal drought is a major constraint to its productivity. We generated expressed sequence tags (ESTs) by suppression subtraction hybridization (SSH) to identify differentially expressed genes in drought-tolerant and -susceptible genotypes in chickpea. Results EST libraries were generated by SSH from root and shoot tissues of IC4958 (drought tolerant) and ICC 1882 (drought resistant) exposed to terminal drought conditions by the dry down method. SSH libraries were also constructed by using 2 sets of bulks prepared from the RNA of root tissues from selected recombinant inbred lines (RILs) (10 each) for the extreme high and low root biomass phenotype. A total of 3062 unigenes (638 contigs and 2424 singletons), 51.4% of which were novel in chickpea, were derived by cluster assembly and sequence alignment of 5949 ESTs. Only 2185 (71%) unigenes showed significant BLASTX similarity (chickpea for the first time. This study not only serves as resource for marker discovery, but can provide a better insight into the selection of candidate genes (both up- and downregulated) associated with drought tolerance. These results can be used to identify suitable targets for manipulating the drought-tolerance trait in chickpea. PMID:21513527

  12. Drought as a natural disaster

    Energy Technology Data Exchange (ETDEWEB)

    Maybank, J. [Agvironics Consulting, SK (Canada); Bonsal, B. [Saskatchewan Univ., Saskatoon, SK (Canada). Dept. of Geography; Jones, K. [Environment Canada, Downsview, ON (Canada). Canadian Climate Centre; Lawford, R. [Canadian Climate Centre, Saskatoon, SK (Canada). National Hydrology Research Centre; O`Brien, E.G. [Agriculture Canada, Ottawa, ON (Canada). Energy Analysis and Policy Div.; Ripley, E.A. [Saskatchewan Univ., Saskatoon, SK (Canada). Dept. of Soil Science; Wheaton, E. [Saskatchewan Research Council, Saskatoon, SK (Canada)

    1995-12-31

    A discussion of droughts as a major natural disaster in dry areas such as the Canadian Prairies where precipitation patterns are seasonal, was presented. Environmental damages include soil degradation and erosion, vegetation damage, slough and lake deterioration and wildlife loss. The development and application of specific soil moisture and drought indices based on cumulative precipitation deficits have enhanced drought monitoring programs. The identification of precursor conditions raises the possibility that the likelihood of a drought occurring in a particular year or growing season might be predictable. The ability to forecast seasonal temperature and precipitation anomalies is potentially feasible using a suitable merging of precursor parameters and modelling methodologies. Research activity to identify and evaluate new mitigative measure should be increased to keep pace with the prospects of drought predictability. 90 refs., 1 tab., 7 figs.

  13. Drought, Sustainability, and the Law

    Directory of Open Access Journals (Sweden)

    Robert W. Adler

    2010-07-01

    Full Text Available Researchers and responsible officials have made considerable progress in recent years in efforts to anticipate, plan for, and respond to drought. Some of those efforts are beginning to shift from purely reactive, relief-oriented measures to programs designed to prevent or to mitigate drought impacts. Considerably less attention has been given to laws that may affect practices and policies that either increase or decrease drought vulnerability. Water law regimes, drought response and relief legislation, and laws governing broader but related issues of economic policy—especially agricultural policy—should be evaluated more comprehensively to enhance incentives for more ―water sustainable‖ practices in agriculture and other sectors of the economy. Those changes will be increasingly important if current climate change models are correct in their prediction that many parts of the world can expect more frequent and more severe conditions of meteorological drought in the ensuing decades.

  14. Investigate the Capabilities of Remotely Sensed Crop Indicators for Agricultural Drought Monitoring in Kansas

    Science.gov (United States)

    Zhang, J.; Becker-Reshef, I.; Justice, C. O.

    2013-12-01

    Although agricultural production has been rising in the past years, drought remains the primary cause of crop failure, leading to food price instability and threatening food security. The recent 'Global Food Crisis' in 2008, 2011 and 2012 has put drought and its impact on crop production at the forefront, highlighting the need for effective agricultural drought monitoring. Satellite observations have proven a practical, cost-effective and dynamic tool for drought monitoring. However, most satellite based methods are not specially developed for agriculture and their performances for agricultural drought monitoring still need further development. Wheat is the most widely grown crop in the world, and the recent droughts highlight the importance of drought monitoring in major wheat producing areas. As the largest wheat producing state in the US, Kansas plays an important role in both global and domestic wheat markets. Thus, the objective of this study is to investigate the capabilities of remotely sensed crop indicators for effective agricultural drought monitoring in Kansas wheat-grown regions using MODIS data and crop yield statistics. First, crop indicators such as NDVI, anomaly and cumulative metrics were calculated. Second, the varying impacts of agricultural drought at different stages were explored by examining the relationship between the derived indicators and yields. Also, the starting date of effective agricultural drought early detection and the key agricultural drought alert period were identified. Finally, the thresholds of these indicators for agricultural drought early warning were derived and the implications of these indicators for agricultural drought monitoring were discussed. The preliminary results indicate that drought shows significant impacts from the mid-growing-season (after Mid-April); NDVI anomaly shows effective drought early detection from Late-April, and Late-April to Early-June can be used as the key alert period for agricultural

  15. Exploring drought vulnerability in Africa: an indicator based analysis to inform early warning systems

    Science.gov (United States)

    Naumann, G.; Barbosa, P.; Garrote, L.; Iglesias, A.; Vogt, J.

    2013-10-01

    Drought vulnerability is a complex concept that includes both biophysical and socio-economic drivers of drought impact that determine capacity to cope with drought. In order to develop an efficient drought early warning system and to be prepared to mitigate upcoming drought events it is important to understand the drought vulnerability of the affected regions. We propose a composite Drought Vulnerability Indicator (DVI) that reflects different aspects of drought vulnerability evaluated at Pan-African level in four components: the renewable natural capital, the economic capacity, the human and civic resources, and the infrastructure and technology. The selection of variables and weights reflects the assumption that a society with institutional capacity and coordination, as well as with mechanisms for public participation is less vulnerable to drought; furthermore we consider that agriculture is only one of the many sectors affected by drought. The quality and accuracy of a composite indicator depends on the theoretical framework, on the data collection and quality, and on how the different components are aggregated. This kind of approach can lead to some degree of scepticism; to overcome this problem a sensitivity analysis was done in order to measure the degree of uncertainty associated with the construction of the composite indicator. Although the proposed drought vulnerability indicator relies on a number of theoretical assumptions and some degree of subjectivity, the sensitivity analysis showed that it is a robust indicator and hence able of representing the complex processes that lead to drought vulnerability. According to the DVI computed at country level, the African countries classified with higher relative vulnerability are Somalia, Burundi, Niger, Ethiopia, Mali and Chad. The analysis of the renewable natural capital component at sub-basin level shows that the basins with high to moderate drought vulnerability can be subdivided in three main different

  16. Exploring drought vulnerability in Africa: an indicator based analysis to inform early warning systems

    Directory of Open Access Journals (Sweden)

    G. Naumann

    2013-10-01

    Full Text Available Drought vulnerability is a complex concept that includes both biophysical and socio-economic drivers of drought impact that determine capacity to cope with drought. In order to develop an efficient drought early warning system and to be prepared to mitigate upcoming drought events it is important to understand the drought vulnerability of the affected regions. We propose a composite Drought Vulnerability Indicator (DVI that reflects different aspects of drought vulnerability evaluated at Pan-African level in four components: the renewable natural capital, the economic capacity, the human and civic resources, and the infrastructure and technology. The selection of variables and weights reflects the assumption that a society with institutional capacity and coordination, as well as with mechanisms for public participation is less vulnerable to drought; furthermore we consider that agriculture is only one of the many sectors affected by drought. The quality and accuracy of a composite indicator depends on the theoretical framework, on the data collection and quality, and on how the different components are aggregated. This kind of approach can lead to some degree of scepticism; to overcome this problem a sensitivity analysis was done in order to measure the degree of uncertainty associated with the construction of the composite indicator. Although the proposed drought vulnerability indicator relies on a number of theoretical assumptions and some degree of subjectivity, the sensitivity analysis showed that it is a robust indicator and hence able of representing the complex processes that lead to drought vulnerability. According to the DVI computed at country level, the African countries classified with higher relative vulnerability are Somalia, Burundi, Niger, Ethiopia, Mali and Chad. The analysis of the renewable natural capital component at sub-basin level shows that the basins with high to moderate drought vulnerability can be subdivided in three

  17. Comparative physiological and transcriptional analyses of two contrasting drought tolerant alfalfa varieties

    Directory of Open Access Journals (Sweden)

    Wenli eQuan

    2016-01-01

    Full Text Available Drought is one of major environmental determinants of plant growth and productivity. Alfalfa (Medicago sativa is a legume perennial forage crop native to the arid and semi-arid environment, which is an ideal candidate to study the biochemical and molecular mechanisms conferring drought resistance in plants. In this study, drought stress responses of two alfalfa varieties, Longdong and Algonquin, were comparatively assayed at the physiological, morphological and transcriptional levels. Under control condition, the drought-tolerant Longdong with smaller leaf size and lower stomata density showed less water loss than the drought-sensitive Algonquin. After exposing to drought stress, Longdong showed less severe cell membrane damage, more proline and ascorbate (ASC contents and less accumulation of H2O2 than Algonquin. Moreover, significantly higher antioxidant enzymes activities after drought treatment were found in Longdong when compared with Algonquin. In addition, transcriptional expression analysis showed that Longdong exhibited significantly higher transcripts of drought-responsive genes in leaf and root under drought stress condition. Taken together, these results indicated that Longdong variety was more drought-tolerant than Algonquin variety as evidenced by less leaf firing, more lateral root number, higher relative aboveground/underground biomass per plant and survival rate.

  18. Developing system robustness analysis for drought risk management: an application on a water supply reservoir

    Directory of Open Access Journals (Sweden)

    M. J. P. Mens

    2015-01-01

    Full Text Available Droughts will likely become more frequent, of greater magnitude and of longer duration in the future due to climate change. Already in the present climate, a variety of drought events may occur with different exceedance frequencies. These frequencies are becoming more uncertain due to climate change. Many methods in support of drought risk management focus on providing insight into changing drought frequencies, and use water supply reliability as key decision criterion. In contrast, robustness analysis focuses on providing insight into the full range of drought events and their impact on a system's functioning. This method has been developed for flood risk systems, but applications on drought risk systems are lacking. This paper aims to develop robustness analysis for drought risk systems, and illustrates the approach through a case study with a water supply reservoir and its users. We explore drought characterization and the assessment of a system's ability to deal with drought events, by quantifying the severity and socio-economic impact of a variety of drought events, both frequent and rare ones. Furthermore, we show the effect of three common drought management strategies (increasing supply, reducing demand and implementing hedging rules on the robustness of the coupled water supply and socio-economic system. The case is inspired by Oologah Lake, a multipurpose reservoir in Oklahoma, United States. Results demonstrate that although demand reduction and supply increase may have a comparable effect on the supply reliability, demand reduction may be preferred from a robustness perspective. To prepare drought management plans for dealing with current and future droughts, it is thus recommended to test how alternative drought strategies contribute to a system's robustness rather than relying solely on water reliability as the decision criterion.

  19. Drought impact on forest carbon dynamics and fluxes in Amazonia.

    Science.gov (United States)

    Doughty, Christopher E; Metcalfe, D B; Girardin, C A J; Amézquita, F Farfán; Cabrera, D Galiano; Huasco, W Huaraca; Silva-Espejo, J E; Araujo-Murakami, A; da Costa, M C; Rocha, W; Feldpausch, T R; Mendoza, A L M; da Costa, A C L; Meir, P; Phillips, O L; Malhi, Y

    2015-03-05

    In 2005 and 2010 the Amazon basin experienced two strong droughts, driven by shifts in the tropical hydrological regime possibly associated with global climate change, as predicted by some global models. Tree mortality increased after the 2005 drought, and regional atmospheric inversion modelling showed basin-wide decreases in CO2 uptake in 2010 compared with 2011 (ref. 5). But the response of tropical forest carbon cycling to these droughts is not fully understood and there has been no detailed multi-site investigation in situ. Here we use several years of data from a network of thirteen 1-ha forest plots spread throughout South America, where each component of net primary production (NPP), autotrophic respiration and heterotrophic respiration is measured separately, to develop a better mechanistic understanding of the impact of the 2010 drought on the Amazon forest. We find that total NPP remained constant throughout the drought. However, towards the end of the drought, autotrophic respiration, especially in roots and stems, declined significantly compared with measurements in 2009 made in the absence of drought, with extended decreases in autotrophic respiration in the three driest plots. In the year after the drought, total NPP remained constant but the allocation of carbon shifted towards canopy NPP and away from fine-root NPP. Both leaf-level and plot-level measurements indicate that severe drought suppresses photosynthesis. Scaling these measurements to the entire Amazon basin with rainfall data, we estimate that drought suppressed Amazon-wide photosynthesis in 2010 by 0.38 petagrams of carbon (0.23-0.53 petagrams of carbon). Overall, we find that during this drought, instead of reducing total NPP, trees prioritized growth by reducing autotrophic respiration that was unrelated to growth. This suggests that trees decrease investment in tissue maintenance and defence, in line with eco-evolutionary theories that trees are competitively disadvantaged in the

  20. Effect of Extreme Drought on Tropical Dry Forests

    Science.gov (United States)

    Castro, Saulo; Sanchez-Azofeifa, Arturo; Sato, Hiromitsu; Cowling, Sharon; Vega-Araya, Mauricio

    2017-04-01

    Tropical dry forests (TDFs) hold a strong economic and cultural connection to human development in the Neotropics. Historically, TDFs not only represent a source of agricultural and urban land but also an important source of goods and ecosystem services for the communities that live around them. Such is the close connection of TDFs to human activity that they are considered the most heavily utilized and disturbed ecosystem in the world. However, TDF have been largely understudied and represent only a fraction of research devoted to globally tropical ecosystems. Thus we lack the framework to properly project how predicted increases in drought events due to climate change will impact TDFs and human society which depend on its services. Our study aims to show the effect of extreme drought on water, food security, and tropical dry forest productivity in the Guanacaste province of Costa Rica. Two pre-ENSO years (2013-2014) and an ENSO year (2015) were compared. The 2013 and 2014 pre-ENSO years were classified as a normal precipitation (1470 mm) and drought year (1027mm), respectively. The 2015 ENSO year was classified as a severe drought (654mm), with amplified effects resulting by the drought experienced during the previous (2014) growing cycle. Effects of the ENSO drought on agriculture and livestock sectors in the province included losses of US13million and US6.5million, respectively. Crop land losses equaled 2,118 hectares and 11,718 hectares were affected. Hydroelectricity generation decreased by 10% and potable water shortages were observed. The Agriculture and Livestock Ministry (MAG) and the National Emergency Commission (CNE) distributed animal feed and supplies to 4,000 farmers affected by the extreme droughts. Eddy covariance flux measurements were used to identify productivity changes during the extreme drought. Changes in phenologic stages and the transitions between CO2 sink to source during mid-growing cycle were observed. Drought significantly delayed

  1. Land-atmosphere interaction and disaster-causing process of drought in northern China: observation and experiment (DroughtPEX_China)

    Science.gov (United States)

    Li, Yaohui

    2017-04-01

    Drought is one of the most common and frequent nature disasters in the world, particularly in China under the continental monsoonal climate with great variation. About thirty percent of economic loss caused by natural disasters is contributed by droughts in China, which is by far the most damaging weather disasters because of its long duration and extensive hazard areas. Droughts not only have a serious impact on the agriculture, water resources, ecology, natural environment, but also seriously affect the socio-economic such as human health, energy and transportation. Worsely, under the background of climate change, droughts in show increases in frequency, duration and scope in many places around the world, particularly northern China. Nowadays, droughts have aroused extensive concern of the scientists, governments and international community, and became one of the important scientific issues in geoscience research. However, most of researches on droughts in China so far were focused on the causes or regulars of one type of droughts (the atmosphere, agriculture or hydrological) from the perspective of the atmospheric circulation anomalies. Few of them considered a whole cycle of the drought-forming process from atmosphere-land interaction to agricultural/ecological one in terms of the land-atmosphere interaction; meanwhile, the feedback mechanism with the drought and land-atmosphere interaction is still unclear as well. All of them is because of lack of the relevant comprehensive observation experiment. "Land-atmosphere interaction and disaster-causing process of drought in northern China: observation and experiment" (DroughtPEX_China)is just launched in this requirement and background. DroughtPEX_China is supported by Special Scientific Research Fund of Public Welfare Industry (Meteorological) of China (Grant No.GYHY201506001)—"Drought Meteorology Scientific Research Project—the disaster-causing process and mechanism of drought in northern China". This project

  2. A review of droughts in the African continent: a geospatial and long-term perspective

    Directory of Open Access Journals (Sweden)

    I. Masih

    2014-03-01

    Full Text Available This paper presents a comprehensive review and analysis of the available literature and information on droughts to build a continental, regional and country level perspective on geospatial and temporal variation of droughts in Africa. The study is based on the review and analysis of droughts occurred during 1900–2013 as well as evidence available from past centuries based on studies on the lake sediment analysis, tree-ring chronologies and written and oral histories and future predictions from the global climate change models. Most of the studies based on instrumental records indicate that droughts have become more frequent, intense and widespread during the last 50 yr. The extreme droughts of 1972–1973, 1983–1984 and 1991–1992 were continental in nature and stand unique in the available records. Additionally, many severe and prolonged droughts were recorded in the recent past such as the 1999–2002 drought in Northwest Africa, 1970s and 1980s droughts in West Africa (Sahel, 2010–2011 drought in East Africa (Horn of Africa and 2001–2003 drought in Southern and Southeast Africa, to name a few. The available (though limited evidence before the 20th century confirms the occurrence of several extreme and multi-year droughts during each century, with the most prolonged and intense droughts that occurred in Sahel and Equatorial East Africa regions. Complex and highly variant nature of many physical mechanisms such as El Niño-Southern Oscillation (ENSO, Sea Surface Temperature (SST and land–atmosphere feedback adds to the daunting challenge of drought monitoring and forecasting. The future predictions of droughts based on global climate models indicate increased droughts and aridity at the continental scale but large differences exist due to model limitations and complexity of the processes especially for Sahel and North Africa regions. However, the available evidence from the past clearly shows that the African continent is likely to

  3. A review of droughts on the African continent: a geospatial and long-term perspective

    Science.gov (United States)

    Masih, I.; Maskey, S.; Mussá, F. E. F.; Trambauer, P.

    2014-09-01

    This paper presents a comprehensive review and analysis of the available literature and information on droughts to build a continental, regional and country level perspective on geospatial and temporal variation of droughts in Africa. The study is based on the review and analysis of droughts occurred during 1900-2013, as well as evidence available from past centuries based on studies on the lake sediment analysis, tree-ring chronologies and written and oral histories and future predictions from the global climate change models. Most of the studies based on instrumental records indicate that droughts have become more frequent, intense and widespread during the last 50 years. The extreme droughts of 1972-1973, 1983-1984 and 1991-1992 were continental in nature and stand unique in the available records. Additionally, many severe and prolonged droughts were recorded in the recent past such as the 1999-2002 drought in northwest Africa, 1970s and 1980s droughts in western Africa (Sahel), 2010-2011 drought in eastern Africa (Horn of Africa) and 2001-2003 drought in southern and southeastern Africa, to name a few. The available (though limited) evidence before the 20th century confirms the occurrence of several extreme and multi-year droughts during each century, with the most prolonged and intense droughts that occurred in Sahel and equatorial eastern Africa. The complex and highly variant nature of many physical mechanisms such as El Niño-Southern Oscillation (ENSO), sea surface temperature (SST) and land-atmosphere feedback adds to the daunting challenge of drought monitoring and forecasting. The future predictions of droughts based on global climate models indicate increased droughts and aridity at the continental scale but large differences exist due to model limitations and complexity of the processes especially for Sahel and northern Africa. However, the available evidence from the past clearly shows that the African continent is likely to face extreme and

  4. A review of droughts in the African continent: a geospatial and long-term perspective

    Science.gov (United States)

    Masih, I.; Maskey, S.; Mussá, F. E. F.; Trambauer, P.

    2014-03-01

    This paper presents a comprehensive review and analysis of the available literature and information on droughts to build a continental, regional and country level perspective on geospatial and temporal variation of droughts in Africa. The study is based on the review and analysis of droughts occurred during 1900-2013 as well as evidence available from past centuries based on studies on the lake sediment analysis, tree-ring chronologies and written and oral histories and future predictions from the global climate change models. Most of the studies based on instrumental records indicate that droughts have become more frequent, intense and widespread during the last 50 yr. The extreme droughts of 1972-1973, 1983-1984 and 1991-1992 were continental in nature and stand unique in the available records. Additionally, many severe and prolonged droughts were recorded in the recent past such as the 1999-2002 drought in Northwest Africa, 1970s and 1980s droughts in West Africa (Sahel), 2010-2011 drought in East Africa (Horn of Africa) and 2001-2003 drought in Southern and Southeast Africa, to name a few. The available (though limited) evidence before the 20th century confirms the occurrence of several extreme and multi-year droughts during each century, with the most prolonged and intense droughts that occurred in Sahel and Equatorial East Africa regions. Complex and highly variant nature of many physical mechanisms such as El Niño-Southern Oscillation (ENSO), Sea Surface Temperature (SST) and land-atmosphere feedback adds to the daunting challenge of drought monitoring and forecasting. The future predictions of droughts based on global climate models indicate increased droughts and aridity at the continental scale but large differences exist due to model limitations and complexity of the processes especially for Sahel and North Africa regions. However, the available evidence from the past clearly shows that the African continent is likely to face extreme and widespread

  5. Changes in the frequency and severity of hydrological droughts over Ethiopia from 1960 to 2013

    KAUST Repository

    El Kenawy, A. M.

    2016-06-27

    Here we present an analysis of drought occurrence and variability in Ethiopia, based on the monthly precipitation data from the Climate Research Unit (CRU-v3.22) over the period from 1960 to 2013. The drought events were characterized by means of the Standardized Precipitation Index (SPI) applied to precipitation data at a temporal scale of 12 months. At the national scale, the results reveal a statistically significant decrease in the severity of droughts over the 54-year period, a pattern that is mostly attributed to a statistically significant decrease in the frequency of high intensity drought episodes (i.e., extreme and very extreme droughts), compared to moderate droughts. To assess the general patterns of drought evolution, a principal component analysis (PCA) was applied to the SPI series. PCA results indicate a high spatial heterogeneity in the SPI variations over the investigated period, with ten different spatially well-defined regions identified. These PCA components accounted for 72.9% of the total variance of drought in the region. These regions also showed considerable differences in the temporal variability of drought, as most of the regions exhibited an increase in wetness conditions in recent decades. In contrast, the regions that receive less than 400 mm of annual precipitation showed a declining  trend, with the largest changes occurring over Afar region. Generally, the highly elevated regions over the central Ethiopian Highlands showed the weakest changes, compared to the lowlands. This study confirms the local character of drought evolution over Ethiopia, providing evidence for policy makers to adopt appropriate local policies to cope with the risks of drought. Over Ethiopia, the detailed spatial assessment of drought evolution is required for a better understanding of the possible impacts of recurrent drought on agriculture, food production, soil degradation, human settlements and migrations, as well as energy production and water resources

  6. Recent advances in the dissection of drought-stress regulatory networks and strategies for development of drought-tolerant transgenic rice plants.

    Science.gov (United States)

    Todaka, Daisuke; Shinozaki, Kazuo; Yamaguchi-Shinozaki, Kazuko

    2015-01-01

    Advances have been made in the development of drought-tolerant transgenic plants, including cereals. Rice, one of the most important cereals, is considered to be a critical target for improving drought tolerance, as present-day rice cultivation requires large quantities of water and as drought-tolerant rice plants should be able to grow in small amounts of water. Numerous transgenic rice plants showing enhanced drought tolerance have been developed to date. Such genetically engineered plants have generally been developed using genes encoding proteins that control drought regulatory networks. These proteins include transcription factors, protein kinases, receptor-like kinases, enzymes related to osmoprotectant or plant hormone synthesis, and other regulatory or functional proteins. Of the drought-tolerant transgenic rice plants described in this review, approximately one-third show decreased plant height under non-stressed conditions or in response to abscisic acid treatment. In cereal crops, plant height is a very important agronomic trait directly affecting yield, although the improvement of lodging resistance should also be taken into consideration. Understanding the regulatory mechanisms of plant growth reduction under drought stress conditions holds promise for developing transgenic plants that produce high yields under drought stress conditions. Plant growth rates are reduced more rapidly than photosynthetic activity under drought conditions, implying that plants actively reduce growth in response to drought stress. In this review, we summarize studies on molecular regulatory networks involved in response to drought stress. In a separate section, we highlight progress in the development of transgenic drought-tolerant rice plants, with special attention paid to field trial investigations.

  7. Recent advances in the dissection of drought-stress regulatory networks and strategies for development of drought-tolerant transgenic rice plants

    Directory of Open Access Journals (Sweden)

    Daisuke eTodaka

    2015-02-01

    Full Text Available Advances have been made in the development of drought-tolerant transgenic plants, including cereals. Rice, one of the most important cereals, is considered to be a critical target for improving drought tolerance, as present-day rice cultivation requires large quantities of water and as drought-tolerant rice plants should be able to grow in small amounts of water. Numerous transgenic rice plants showing enhanced drought tolerance have been developed to date. Such genetically engineered plants have generally been developed using genes encoding proteins that control drought regulatory networks. These proteins include transcription factors, protein kinases, receptor-like kinases, enzymes related to osmoprotectant or plant hormone synthesis, and other regulatory or functional proteins. Of the drought-tolerant transgenic rice plants described in this review, approximately one-third show decreased plant height under non-stressed conditions or in response to abscisic acid treatment. In cereal crops, plant height is a very important agronomic trait directly affecting yield, although the improvement of lodging resistance should also be taken into consideration. Understanding the regulatory mechanisms of plant growth reduction under drought stress conditions holds promise for developing transgenic plants that produce high yields under drought stress conditions. Plant growth rates are reduced more rapidly than photosynthetic activity under drought conditions, implying that plants actively reduce growth in response to drought stress. In this review, we summarize studies on molecular regulatory networks involved in response to drought stress. In a separate section, we highlight progress in the development of transgenic drought-tolerant rice plants, with special attention paid to field trial investigations.

  8. miRNA-based drought regulation in wheat.

    Science.gov (United States)

    Akdogan, Guray; Tufekci, Ebru Derelli; Uranbey, Serkan; Unver, Turgay

    2016-05-01

    MicroRNAs (miRNAs) are a class of small non-coding regulatory RNAs that regulate gene expression by guiding target mRNA cleavage or translational inhibition. Drought is a common environmental stress influencing crop growth and development. To date, it has been reported that a number of plant miRNA are involved in drought stress response. In this study, we comparatively investigated drought stress-responsive miRNAs in the root and leaf of bread wheat (Triticum aestivum cv. Sivas 111/33) by miRNA microarray screening. miRNA microarray analysis showed that 285 miRNAs (207 upregulated and 78 downregulated) and 244 miRNAs (115 upregulated and 129 downregulated) were differentially expressed in leaf and root tissues, respectively. Among the differentially expressed miRNAs, 23 miRNAs were only expressed in the leaf and 26 miRNAs were only expressed in the root of wheat growth under drought stress. Upon drought treatment, expression of miR159, miR160, miR166, miR169, miR172, miR395, miR396, miR408, miR472, miR477, miR482, miR1858, miR2118, and miR5049 were found to be significantly differentiated in bread wheat. The regulatory network analysis showed that miR395 has connections with a number of target transcripts, and miR159 and miR319 share a number of target genes. Drought-tolerant and drought-sensitive wheat cultivars showed altered expression pattern upon drought stress in terms of investigated miRNA and their target transcript expression level.

  9. Capability of meteorological drought indices for detecting soil moisture droughts

    Directory of Open Access Journals (Sweden)

    Devanmini Halwatura

    2017-08-01

    New hydrological insights for the region: For three typical soil types and climate zones in Eastern Australia, and for two soil profiles, we have found a significant correlation between the indices and soil moisture droughts detected by Hydrus-1D. The failure rates and false alarm rates for detecting the simulated soil moisture droughts were generally below 50% for both indices and both soil profiles (the Reconnaissance Drought Index at Melbourne was the only exception. However, the complexity of Hydrus-1D and the uncertainty associated with the available, regionalised soil water retention curves encourage using the indices over Hydrus-1D in absence of appropriate soil moisture monitoring data.

  10. Origin and fate of repeats in bacteria.

    Science.gov (United States)

    Achaz, G; Rocha, E P C; Netter, P; Coissac, E

    2002-07-01

    We investigated 53 complete bacterial chromosomes for intrachromosomal repeats. In previous studies on eukaryote chromosomes, we proposed a model for the dynamics of repeats based on the continuous genesis of tandem repeats, followed by an active process of high deletion rate, counteracted by rearrangement events that may prevent the repeats from being deleted. The present study of long repeats in the genomes of Bacteria and Archaea suggests that our model of interspersed repeats dynamics may apply to them. Thus the duplication process might be a consequence of very ancient mechanisms shared by all three domains. Moreover, we show that there is a strong negative correlation between nucleotide composition bias and the repeat density of genomes. We hypothesise that in highly biased genomes, non-duplicated small repeats arise more frequently by random effects and are used as primers for duplication mechanisms, leading to a higher density of large repeats.

  11. Dendroindication of drought in Rogatica region (Eastern Bosnia

    Directory of Open Access Journals (Sweden)

    Ducić Vladan

    2015-01-01

    Full Text Available The aim of this study was to investigate the possibility of using the dendrochronological method in drought prediction in eastern Bosnia. As an indicator of drought, the standardized precipitation index (SPI was used. In the wider area of Rogatica (eastern Bosnia, 11 core samples from trees were taken. The best connection between the width of tree rings and drought was shown by the sample of a 67-year-old European silver fir (Abies alba from the mountain Bokšanica. Removal of the biological trend (standardization was performed by the autoregressive-moving-average (ARMA method. Calculations showed that precipitation, i.e. drought in the summer months, is crucial for radial increment of the sample. The obtained results of our research have been confirmed in examples in the region and further. [47007

  12. Stress memory and the inevitable effects of drought: a physiological perspective

    Directory of Open Access Journals (Sweden)

    Eva eFleta-Soriano

    2016-02-01

    Full Text Available Plants grow and develop by adjusting their physiology to changes in their environment. Changes in the abiotic environment occur over years, seasons and days, but also over minutes and even seconds. In this ever-changing environment, plants may adjust their structure and function rapidly to optimize growth and reproduction. Plant responses to reiterated drought (i.e. repeated cycles of drought differ from those to single incidences of drought; in fact, in nature, plants are usually exposed to repeated cycles of drought that differ in duration and intensity. Nowadays, there is increased interest in better understanding mechanisms of plant response to reiterated drought due, at least in part, to the discovery of epigenomic changes that trigger drought stress memory in plants. Beyond epigenomic changes, there are, however, other aspects that should be considered in the study of plant responses to reiterated drought: from changes in other omics approaches (transcriptomics, proteomics and metabolomics, to changes in plant structure; all of which may help us to better understand plant stress memory and its underlying mechanisms. Here, we present an example in which reiterated drought affects the pigment composition of leaves in the ornamental plant Silene dioica and discuss the importance of structural changes (in this case in the photosynthetic apparatus for the plant response to reiterated drought; they represent a stress imprint that can affect plant response to subsequent stress episodes. Emphasis is placed on the importance of considering structural changes, in addition to physiological adjustments at the omics level, to understand stress memory in

  13. Assessment of Precipitation and Drought Variability in Weihe River of China Over the Period 1960-2010

    Science.gov (United States)

    Chang, J.; Wang, Y.

    2015-12-01

    The amount and distribution of precipitation play crucial roles in the occurrence of drought in the Weihe River Basin (WRB) of China. Using the precipitation data (1960-2010) of 21 meteorological stations, the spatial and temporal characteristics of droughts were examined by using theory of runs and the Standardized Precipitation Index on 3-month, 6-month and 12-month time scales. The results showed that the main drought type was moderate drought, and drought occurred frequently on July and October. During the last 50 years, the drought intensity and frequency were the biggest in 1991-2000. According to the SPI-3, the risk of spring and fall drought increased gradually, which could impact on agriculture and water supply. The trend of SPI values over the time period was calculated and analyzed, showing of increasing dryness throughout the basin, and the north and northwest zones of WRB were most likely to suffer from drought. Also, compared with the east, the drought severity and drought duration in the northwest was more serious. It was also observed that there was strong relation between precipitation distribution and drought zones in the basin, and the drought conditions changed continuously with seasons depending upon precipitation amount and its spatial distribution.

  14. Drought analysis in Switzerland: spatial and temporal features

    Science.gov (United States)

    Di Franca, Gaetano; Molnar, Peter; Burlando, Paolo; Bonaccorso, Brunella; Cancelliere, Antonino

    2015-04-01

    Drought as a natural hazard may have negative impacts even in regions characterized by a general abundance of water resources. The Swiss Alpine region has experienced several extreme meteorological events (heat waves, droughts) during the last fifty years that have caused human and economic losses. Though Swiss climate is far from arid or semi-arid, natural climatic variability, exacerbated by climate change, could lead to more severe impacts from naturally occurring meteorological droughts (i.e. lack or significant reduction of precipitation) in the future. In this work, spatial and temporal features of meteorological droughts in Switzerland have been explored by the identification and probabilistic characterization of historic drought events on gridded precipitation data during the period 1961-2012. The run method has been applied to both monthly and annual precipitation time series to probabilistically characterize drought occurrences as well as to analyze their spatial variability. Spatial features have also been investigated by means of Principal Components Analysis (PCA) applied to Standardized Precipitation Index (SPI) series at 3, 6, and 12-month aggregated time scale, in order to detect areas with distinct precipitation patterns, accounting for seasonality throughout year and including both wet and dry conditions. Furthermore, a probabilistic analysis of drought areal extent has been carried out by applying an SPI-based procedure to derive Severity-Area-Frequency (SAF) curves. The application of run method reveals that Ticino and Valais are the most potentially drought-prone Swiss regions, since accumulated deficit precipitation is significantly higher (up to two times) than in the rest of the country. Inspection of SPI series reveals many events in which precipitation has shown significant anomalies from the average in the period 1961-2012 at the investigated time scales. Anomalies in rainfall seem to exhibit high spatial correlation, showing uniform sub

  15. DroughtView: Satellite Based Drought Monitoring and Assessment

    Science.gov (United States)

    Hartfield, K. A.; Van Leeuwen, W. J. D.; Crimmins, M.; Marsh, S. E.; Torrey, Y.; Rahr, M.; Orr, B. J.

    2014-12-01

    Drought is an ever growing concern within the United States and Mexico. Extended periods of below-average precipitation can adversely affect agricultural production and ecosystems, impact local water resources and create conditions prime for wildfire. DroughtView (www.droughtview.arizona.edu) is a new on-line resource for scientists, natural resource managers, and the public that brings a new perspective to remote-sensing based drought impact assessment that is not currently available. DroughtView allows users to monitor the impact of drought on vegetation cover for the entire continental United States and the northern regions of Mexico. As a spatially and temporally dynamic geospatial decision support tool, DroughtView is an excellent educational introduction to the relationship between remotely sensed vegetation condition and drought. The system serves up Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI) data generated from 250 meter 16-day composite Moderate-resolution Imaging Spectroradiometer (MODIS) imagery from 2000 to the present. Calculation of difference from average, previous period and previous year greenness products provide the user with a proxy for drought conditions and insight on the secondary impacts of drought, such as wildfire. The various image products and overlays are served up via the ArcGIS Server platform. DroughtView serves as a useful tool to introduce and teach vegetation time series analysis to those unfamiliar with the science. High spatial resolution imagery is available as a reference layer to locate points of interest, zoom in and export images for implementation in reports and presentations. Animation of vegetation time series allows users to examine ecosystem disturbances and climate data is also available to examine the relationship between precipitation, temperature and vegetation. The tool is mobile friendly allowing users to access the system while in the field. The systems capabilities and

  16. Comparative transcriptomic analysis reveals the roles of overlapping heat-/drought-responsive genes in poplars exposed to high temperature and drought

    Science.gov (United States)

    Jia, Jingbo; Zhou, Jing; Shi, Wenguang; Cao, Xu; Luo, Jie; Polle, Andrea; Luo, Zhi-Bin

    2017-01-01

    High temperature (HT) and drought are both critical factors that constrain tree growth and survival under global climate change, but it is surprising that the transcriptomic reprogramming and physiological relays involved in the response to HT and/or drought remain unknown in woody plants. Thus, Populus simonii saplings were exposed to either ambient temperature or HT combined with sufficient watering or drought. RNA-sequencing analysis showed that a large number of genes were differentially expressed in poplar roots and leaves in response to HT and/or desiccation, but only a small number of these genes were identified as overlapping heat-/drought-responsive genes that are mainly involved in RNA regulation, transport, hormone metabolism, and stress. Furthermore, the overlapping heat-/drought-responsive genes were co-expressed and formed hierarchical genetic regulatory networks under each condition compared. HT-/drought-induced transcriptomic reprogramming is linked to physiological relays in poplar roots and leaves. For instance, HT- and/or drought-induced abscisic acid accumulation and decreases in auxin and other phytohormones corresponded well with the differential expression of a few genes involved in hormone metabolism. These results suggest that overlapping heat-/drought-responsive genes will play key roles in the transcriptional and physiological reconfiguration of poplars to HT and/or drought under future climatic scenarios. PMID:28233854

  17. Low root reserve accumulation during drought may lead to winter mortality in poplar seedlings.

    Science.gov (United States)

    Galvez, David A; Landhäusser, S M; Tyree, M T

    2013-04-01

    Climate models suggest that more frequent drought events of greater severity and length, associated with climate change, can be expected in the coming decades. Although drought-induced tree mortality has been recognized as an important factor modulating forest demography at the global scale, the mechanisms underlying drought-induced tree mortality remain contentious. Above- and below-ground growth, gas exchange, water relations and carbon reserve accumulation dynamics at the organ and whole-plant scale were quantified in Populus tremuloides and P. balsamifera seedlings in response to severe drought. Seedlings were maintained in drought conditions over one growing and one dormant winter season. Our experiment presents a detailed description of the effect of severe drought on growth and physiological variables, leading to seedling mortality after an extended period of drought and dormancy. After re-watering following the dormant period, drought-exposed seedlings did not re-flush, showing that the root system had died off. The results of this study suggest a complex series of physiological feedbacks between the measured variables in both Populus species. Further, they reveal that reduced reserve accumulation in the root system during drought decreases the conversion of starch to soluble sugars in roots, which may contribute to the root death of drought-exposed seedlings during the dormant season by compromising the frost tolerance of the root system. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  18. Drought analysis in the Eastern Nile basin using the standardized precipitation index.

    Science.gov (United States)

    Elkollaly, Mohamed; Khadr, Mosaad; Zeidan, Bakenaz

    2017-01-31

    Drought is considered by many researchers to be the most complex but least understood of all natural hazards, affecting more people than any other hazard. Drought affects many aspects of community and environment, and any future increases in the water demand will be most critical in periods of severe drought. Geospatial analysis of the historical drought events and their causes can be used to mitigate drought impacts and to develop preparedness plans. This study aimed to identify the changes in drought frequency, magnitude, duration, and intensity in the Eastern Nile basin during the period 1965-2000, using the standardized precipitation index (SPI). An SPI program based on C sharp language was developed to monitor drought in the study area. Twenty-eight meteorological stations distributed on the Eastern Nile basin were chosen to collect monthly precipitation data. For drought analysis, SPI series of 3-, 6-, 9-, 12-, and 24-month timescales have been calculated. Results showed that the study area received several drought events during the long rainy season (June to September) and the short rainy season (March to May) as well. Annual analysis of SPI time series indicated that the study area received several drought events, and the most severity event was during the year 1984.

  19. Drought Index Analizes With Rainfall Patern Indicators Use SPI Method (Case Study Bangga Watershed

    Directory of Open Access Journals (Sweden)

    Beti Mayasari

    2017-05-01

    Full Text Available Irregular weather and climate changes caused by El – Nino effect drought in some areas, including in Indonesia. The location of this study lies in the Bangga watershed. The purpose of this study was to determine rainfall patterns, drought level, the worst drought that occurred and the prediction for the future. One method for analysis of drought is using SPI (Standardized Precipitation Index. This method aims to calculate the value of a drought index that would indicate the level of the existing drought in a region. Data used are monthly rainfall from two station for 23 years (year 1993-2015. After analyzing the drought, the projection made with software Makesens 1.0. The study results showed that the worst drought in Bangga watershed occurred in April 2015 with drought index -3516 for one monthly SPI, -2815 for three monthly SPI, -3254 for six monthly SPI, -2171 for nine monthly SPI, and - 2922 for twelve 12 monthly SPI. Once projected until 2050, generally Bangga watershed experiencing dry conditions with the worst drought in July with a value of -3.83 for one monthly SPI, -3.65 for three monthly SPI, -3.44 for six monthly SPI, -2.6 for nine monthly SPI and -2.32 for twelve monthly SPI.

  20. Characterization of extreme flood and drought events in Singapore and investigation of their relationships with ENSO

    Science.gov (United States)

    Li, Xin; Babovic, Vladan

    2016-04-01

    Flood and drought are hydrologic extreme events that have significant impact on human and natural systems. Characterization of flood and drought in terms of their start, duration and strength, and investigation of the impact of natural climate variability (i.e., ENSO) and anthropogenic climate change on them can help decision makers to facilitate adaptions to mitigate potential enormous economic costs. To date, numerous studies in this area have been conducted, however, they are primarily focused on extra-tropical regions. Therefore, this study presented a detailed framework to characterize flood and drought events in a tropical urban city-state (i.e., Singapore), based on daily data from 26 precipitation stations. Flood and drought events are extracted from standardized precipitation anomalies from monthly to seasonal time scales. Frequency, duration and magnitude of flood and drought at all the stations are analyzed based on crossing theory. In addition, spatial variation of flood and drought characteristics in Singapore is investigated using ordinary kriging method. Lastly, the impact of ENSO condition on flood and drought characteristics is analyzed using regional regression method. The results show that Singapore can be prone to extreme flood and drought events at both monthly and seasonal time scales. ENSO has significant influence on flood and drought characteristics in Singapore, but mainly during the South West Monsoon season. During the El Niño phase, drought can become more extreme. The results have implications for water management practices in Singapore.

  1. Increasing flexibility in rangeland management during drought

    OpenAIRE

    Kachergis, E; Derner, JD; Cutts, BB; Roche, LM; Eviner, VT; Lubell, MN; Tate, KW

    2014-01-01

    Extreme droughts like the recent 2011-2013 drought impacting the central and western United States present a challenge to sustaining livestock ranching operations and the ecosystem goods and services they produce. Wyoming ranchers manage half of this drought-prone state and are at the forefront of this challenge. We examined Wyoming ranchers' drought management strategies and how ranch characteristics affect drought management flexibility, a key component of resilience, through a mail survey....

  2. Drought analysis in middle Heihe River

    Institute of Scientific and Technical Information of China (English)

    Jin Junying; Zhang Zhenwei; Zhang Weihua

    2005-01-01

    Water shortage has become one of the severest problems in the middle Heihe River Basin because of high water demand but low available water supply. This paper is oriented to provide solutions to the problem through the analysis of drought. The main objectives to analyze the difference between water demand and supply in various water users in past, present (2000), and project (2010) situation, especially in agriculture, and the most important is to propose and assess a reasonable measure with the purpose of minimum drought and sustainable development. A simulation model, WAFLEX (Water Allocation Flow model in Excel) model is applied in this study to cope with water availability, distribution and requirement of various water users, and the result shows the model and the method is effective and feasible.

  3. Assessing various drought indicators in representing summer drought in boreal forests in Finland

    Science.gov (United States)

    Gao, Y.; Markkanen, T.; Thum, T.; Aurela, M.; Lohila, A.; Mammarella, I.; Kämäräinen, M.; Hagemann, S.; Aalto, T.

    2016-01-01

    Droughts can have an impact on forest functioning and production, and even lead to tree mortality. However, drought is an elusive phenomenon that is difficult to quantify and define universally. In this study, we assessed the performance of a set of indicators that have been used to describe drought conditions in the summer months (June, July, August) over a 30-year period (1981-2010) in Finland. Those indicators include the Standardized Precipitation Index (SPI), the Standardized Precipitation-Evapotranspiration Index (SPEI), the Soil Moisture Index (SMI), and the Soil Moisture Anomaly (SMA). Herein, regional soil moisture was produced by the land surface model JSBACH of the Max Planck Institute for Meteorology Earth System Model (MPI-ESM). Results show that the buffering effect of soil moisture and the associated soil moisture memory can impact on the onset and duration of drought as indicated by the SMI and SMA, while the SPI and SPEI are directly controlled by meteorological conditions. In particular, we investigated whether the SMI, SMA and SPEI are able to indicate the Extreme Drought affecting Forest health (EDF), which we defined according to the extreme drought that caused severe forest damages in Finland in 2006. The EDF thresholds for the aforementioned indicators are suggested, based on the reported statistics of forest damages in Finland in 2006. SMI was found to be the best indicator in capturing the spatial extent of forest damage induced by the extreme drought in 2006. In addition, through the application of the EDF thresholds over the summer months of the 30-year study period, the SPEI and SMA tended to show more frequent EDF events and a higher fraction of influenced area than SMI. This is because the SPEI and SMA are standardized indicators that show the degree of anomalies from statistical means over the aggregation period of climate conditions and soil moisture, respectively. However, in boreal forests in Finland, the high initial soil moisture

  4. 2006–2015 mega-drought in the western USA and its monitoring from space data

    Directory of Open Access Journals (Sweden)

    Felix Kogan

    2015-11-01

    Full Text Available During 2014 and early 2015, scientific and online publications strongly focused on the multi-year drought over the western USA, showing its dramatic consequences for the US economy, environment and society. Considering such an extraordinary drought, many questions related to its beginning, duration, dynamics, intensity, genesis, extent and frequency became unanswered and even became controversial. How different is this current event from the extraordinary US drought of the 1930s and other intensive droughts? Can this drought be classified as a mega-drought? This paper attempts to answer most of these questions, by applying National Oceanic and Atmospheric Administration (NOAA global operational satellite system estimating vegetation health. It has been shown that the latest western US drought began in 2006 and has continued for nine full years. Since vegetation stress still continues in the first few months of 2015 (when this paper is written coming into the 10th year, this drought was classified as a “mega-drought”. In 2006, when the drought began, vegetation was stressed in over 61% of the western USA. During 2012 and 2013 (time of the drought's intensification, this area increased to 71% and 67%, respectively. All 17 states of the western two-thirds of the USA were affected by this drought, especially South Dakota, Nebraska, Oklahoma, Texas, Montana and Wyoming with up to 100% of the area affected by severe vegetation stress during 2012–2014. Compared to other catastrophic droughts of the past 100 years, the current drought during the worst year (2012, affected 71.3% of the western USA. This is comparable to the area affected by a catastrophic drought in 1934 (71.6% and much higher than the droughts in 1956 (49% and 1988 (31%. In terms of number of drought years, the other droughts in the western USA (1985–1986, 1988–1992, 1995–1996, and 2001–2003 were shorter and less intensive. Among western states, California was the most

  5. Drought, climate change and vegetation response in the succulent karoo, South Africa

    Directory of Open Access Journals (Sweden)

    M. T. Hoffman

    2009-12-01

    Full Text Available For the winter-rainfall region of South Africa, the frequency of drought is predicted to increase over the next 100 years, with dire consequences for the vegetation of this biodiversity hotspot. We analysed historical 20th century rainfall records for six rainfall stations within the succulent karoo biome to determine if the signal of increasing drought frequency is already apparent, and whether mean annual rainfall is decreasing. We found no evidence for a decrease either in mean annual rainfall or in the incidence of drought, as measured by the Standardised Precipitation Index (SPI over the 20th century. Evidence points to a drying trend from 1900–1950 while no significant trend in rainfall and drought was found at most stations from 1951–2000. In a second analysis we synthesised the information concerning the response of adult succulent karoo biome plants and seedlings to extended drought conditions. General findings are that responses to drought differ between species, and that longevity is an important life history trait related to drought survival. Growth form is a poor predictor of drought response across the biome. There was a range of responses to drought among adult plants of various growth forms, and among non-succulent seedlings. Leaf-succulent seedlings, however, exhibited phenomenal drought resistance, the majority surviving drought long after all the experimentally comparative non-succulent seedlings had died. Our synthesis showed that previous studies on the impact of drought on succulent karoo biome plants differ greatly in terms of their location, sampling design, measured values and plant responses. A suite of coordinated long-term field observations, experiments and models are therefore needed to assess the response of succulent karoo biome species to key drought events as they occur over time and to integrate this information into conservation planning.

  6. Effects of meteorological droughts on agricultural water resources in southern China

    Science.gov (United States)

    Lu, Houquan; Wu, Yihua; Li, Yijun; Liu, Yongqiang

    2017-05-01

    With the global warming, frequencies of drought are rising in the humid area of southern China. In this study, the effects of meteorological drought on the agricultural water resource based on the agricultural water resource carrying capacity (AWRCC) in southern China were investigated. The entire study area was divided into three regions based on the distributions of climate and agriculture. The concept of the maximum available water resources for crops was used to calculate AWRCC. Meanwhile, an agricultural drought intensity index (ADI), which was suitable for rice planting areas, was proposed based on the difference between crop water requirements and precipitation. The actual drought area and crop yield in drought years from 1961 to 2010 were analyzed. The results showed that ADI and AWRCC were significantly correlated with the actual drought occurrence area and food yield in the study area, which indicated ADI and AWRCC could be used in drought-related studies. The effects of seasonal droughts on AWRCC strongly depended on both the crop growth season and planting structure. The influence of meteorological drought on agricultural water resources was pronounced in regions with abundant water resources, especially in Southwest China, which was the most vulnerable to droughts. In Southwest China, which has dry and wet seasons, reducing the planting area of dry season crops and rice could improve AWRCC during drought years. Likewise, reducing the planting area of double-season rice could improve AWRCC during drought years in regions with a double-season rice cropping system. Our findings highlight the importance of adjusting the proportions of crop planting to improve the utilization efficiency of agricultural water resources and alleviate drought hazards in some humid areas.

  7. Quantifying sensitivity to droughts – an experimental modeling approach

    Directory of Open Access Journals (Sweden)

    M. Staudinger

    2014-07-01

    Full Text Available Meteorological droughts like those in summer 2003 or spring 2011 in Europe are expected to become more frequent in the future. Although the spatial extent of these drought events was large, not all regions were affected in the same way. Many catchments reacted strongly to the meteorological droughts showing low levels of streamflow and groundwater, while others hardly reacted. The extent of the hydrological drought for specific catchments was also different between these two historical events due to different initial conditions and drought propagation processes. This leads to the important question of how to detect and quantify the sensitivity of a catchment to meteorological droughts. To assess this question we designed hydrological model experiments using a conceptual rainfall–runoff model. Two drought scenarios were constructed by selecting precipitation and temperature observations based on certain criteria: one scenario was a modest but constant progression of drying based on sorting the years of observations according to annual precipitation amounts. The other scenario was a more extreme progression of drying based on selecting months from different years, forming a year with the wettest months through to a year with the driest months. Both scenarios retained the typical intra-annual seasonality for the region. The sensitivity of 24 Swiss catchments to these scenarios was evaluated by analyzing the simulated discharge time series and modeled storages. Mean catchment elevation, slope and size were found to be the main controls on the sensitivity of catchment discharge to precipitation. Generally, catchments at higher elevation and with steeper slopes seemed to be less sensitive to meteorological droughts than catchments at lower elevations with less steep slopes.

  8. Drought-Induced Leaf Proteome Changes in Switchgrass Seedlings

    Directory of Open Access Journals (Sweden)

    Zhujia Ye

    2016-08-01

    Full Text Available Switchgrass (Panicum virgatum is a perennial crop producing deep roots and thus highly tolerant to soil water deficit conditions. However, seedling establishment in the field is very susceptible to prolonged and periodic drought stress. In this study, a “sandwich” system simulating a gradual water deletion process was developed. Switchgrass seedlings were subjected to a 20-day gradual drought treatment process when soil water tension was increased to 0.05 MPa (moderate drought stress and leaf physiological properties had expressed significant alteration. Drought-induced changes in leaf proteomes were identified using the isobaric tags for relative and absolute quantitation (iTRAQ labeling method followed by nano-scale liquid chromatography mass spectrometry (nano-LC-MS/MS analysis. Additionally, total leaf proteins were processed using a combinatorial library of peptide ligands to enrich for lower abundance proteins. Both total proteins and those enriched samples were analyzed to increase the coverage of the quantitative proteomics analysis. A total of 7006 leaf proteins were identified, and 257 (4% of the leaf proteome expressed a significant difference (p < 0.05, fold change <0.6 or >1.7 from the non-treated control to drought-treated conditions. These proteins are involved in the regulation of transcription and translation, cell division, cell wall modification, phyto-hormone metabolism and signaling transduction pathways, and metabolic pathways of carbohydrates, amino acids, and fatty acids. A scheme of abscisic acid (ABA-biosynthesis and ABA responsive signal transduction pathway was reconstructed using these drought-induced significant proteins, showing systemic regulation at protein level to deploy the respective mechanism. Results from this study, in addition to revealing molecular responses to drought stress, provide a large number of proteins (candidate genes that can be employed to improve switchgrass seedling growth and

  9. Drought-Induced Leaf Proteome Changes in Switchgrass Seedlings.

    Science.gov (United States)

    Ye, Zhujia; Sangireddy, Sasikiran; Okekeogbu, Ikenna; Zhou, Suping; Yu, Chih-Li; Hui, Dafeng; Howe, Kevin J; Fish, Tara; Thannhauser, Theodore W

    2016-01-01

    Switchgrass (Panicum virgatum) is a perennial crop producing deep roots and thus highly tolerant to soil water deficit conditions. However, seedling establishment in the field is very susceptible to prolonged and periodic drought stress. In this study, a "sandwich" system simulating a gradual water deletion process was developed. Switchgrass seedlings were subjected to a 20-day gradual drought treatment process when soil water tension was increased to 0.05 MPa (moderate drought stress) and leaf physiological properties had expressed significant alteration. Drought-induced changes in leaf proteomes were identified using the isobaric tags for relative and absolute quantitation (iTRAQ) labeling method followed by nano-scale liquid chromatography mass spectrometry (nano-LC-MS/MS) analysis. Additionally, total leaf proteins were processed using a combinatorial library of peptide ligands to enrich for lower abundance proteins. Both total proteins and those enriched samples were analyzed to increase the coverage of the quantitative proteomics analysis. A total of 7006 leaf proteins were identified, and 257 (4% of the leaf proteome) expressed a significant difference (p 1.7) from the non-treated control to drought-treated conditions. These proteins are involved in the regulation of transcription and translation, cell division, cell wall modification, phyto-hormone metabolism and signaling transduction pathways, and metabolic pathways of carbohydrates, amino acids, and fatty acids. A scheme of abscisic acid (ABA)-biosynthesis and ABA responsive signal transduction pathway was reconstructed using these drought-induced significant proteins, showing systemic regulation at protein level to deploy the respective mechanism. Results from this study, in addition to revealing molecular responses to drought stress, provide a large number of proteins (candidate genes) that can be employed to improve switchgrass seedling growth and establishment under soil drought conditions (Data are

  10. Drought Assessment in Zacatecas, Mexico

    National Research Council Canada - National Science Library

    Bautista-Capetillo, Carlos; Carrillo, Brenda; Picazo, Gonzalo; Júnez-Ferreira, Hugo

    2016-01-01

    ... activities, particularly those related to agriculture and livestock. This research reports on drought assessment for Zacatecas, Mexico using monthly data from 111 weather stations with temperature and precipitation information from a 33-year period...

  11. Assessing Vulnerability to Drought on a pan-European scale

    Science.gov (United States)

    Urquijo, Julia; De Stefano, Lucia; González-Tánago, Itziar; Blauhut, Veit; Stahl, Kerstin

    2014-05-01

    During the past decade, a number of theoretical frameworks have been defined within the Disaster Risk Reduction and Climate Change communities to assess drought vulnerability at different scales, sectors, socio-political contexts, and geo-climatic conditions. However, there is still little consensus around the criteria, dimensions and factors used in these assessments; and none of them has been applied at a pan-European scale. This is due to a triple complexity. Firstly, drought as a natural hazard is a complex phenomenon due to the difficulty of determining its onset and its multiscale, multifaceted and dynamic nature. Secondly, there is an on-going debate regarding the concept of vulnerability and its constitutive elements, together with an important diversity of theoretical approaches to assess it. Finally, Europe's diversity in bioclimatic conditions, national water use practice and water use policies adds a challenging characteristic for working on pan-European scale. This work addresses the challenge of defining a methodological approach to the assessment of vulnerability factors to drought at a pan-European scale. For this purpose, we first review existing conceptual frameworks as well as of past initiatives for drought vulnerability assessment. The literature review showed that the high complexity of drought vulnerability assessment requires a clear definition of the concept of vulnerability and the associated terms, and that, before undertaking any assessment, it is necessary to clearly define the "vulnerable unit" i.e. replying to the questions 'whose vulnerability is being assessed?' and 'vulnerability to what type of impact?'. In this context, this work proposes the application of a factor-based approach, consisting in the analysis of significant factors that influence vulnerability in the context of specific situations of potential vulnerability. Those situations are framed within the specific drought characteristics of four different geoclimatic macro

  12. Drought in Northeast Brazil—past, present, and future

    Science.gov (United States)

    Marengo, Jose A.; Torres, Roger Rodrigues; Alves, Lincoln Muniz

    2016-06-01

    This study provides an overview of the drought situation in Northeast Brazil for the past, present, and future. Droughts affect more people than any other natural hazard owing to their large scale and long-lasting nature. They are recurrent in the region and while some measures have been taken by the governments to mitigate their impacts, there is still a perception that residents, mainly in rural areas, are not yet adapted to these hazards. The drought affecting the Northeast from 2012 to 2015, however, has had an intensity and impact not seen in several decades and has already destroyed large swaths of cropland, affecting hundreds of cities and towns across the region, and leaving ranchers struggling to feed and water cattle. Future climate projections for the area show large temperature increases and rainfall reductions, which, together with a tendency for longer periods with consecutive dry days, suggest the occurrence of more frequent/intense dry spells and droughts and a tendency toward aridification in the region. All these conditions lead to an increase in evaporation from reservoirs and lakes, affecting irrigation and agriculture as well as key water uses including hydropower and industry, and thus, the welfare of the residents. Integrating drought monitoring and seasonal forecasting provides efficient means of assessing impacts of climate variability and change, identifying vulnerabilities, and allowing for better adaptation measures not only for medium- and long-term climate change but also for extremes of the interannual climate variability, particularly droughts.

  13. Evaluation of Drought Tolerance in Some of Winter Canola Cultivars

    Directory of Open Access Journals (Sweden)

    J Rashidifar

    2012-10-01

    Full Text Available In order to evaluate terminal drought tolerance in different Canola cultivars based on drought tolerance indices, an experiment was conducted based on randomized complete block design (RCBD with three replications at experimental field of Seed and Plant Improvement Institute (SPII, Karaj in 2008-09. Results using stress tolerance index (STI, geometric mean productivity (GMP and mean productivity (MP indices revealed Zarfam, Talaye and GKH305, were as cultivars with highest yield in both optimum irrigation and terminal drought conditions. High and positive correlation between STI, GMP and MP indices with yield in optimum and drought conditions indicated that they were as the best indices for introduction and characterization of drought tolerant canola cultivars. Biplot graph showed that MP, GMP and STI indices had high correlation coefficient with each other, and tolerant genotypes were located near tolerance indices. Also results of three dimensional scatter plot indicated that cultivars Zarfam, GKH 305 and Tassilo were recognized as tolerant genotypes to drought stress, and cultivars ES Astrid, GK Helena, Modena and Okapi were identified as sensitive genotypes.

  14. Drought in Northeast Brazil—past, present, and future

    Science.gov (United States)

    Marengo, Jose A.; Torres, Roger Rodrigues; Alves, Lincoln Muniz

    2017-08-01

    This study provides an overview of the drought situation in Northeast Brazil for the past, present, and future. Droughts affect more people than any other natural hazard owing to their large scale and long-lasting nature. They are recurrent in the region and while some measures have been taken by the governments to mitigate their impacts, there is still a perception that residents, mainly in rural areas, are not yet adapted to these hazards. The drought affecting the Northeast from 2012 to 2015, however, has had an intensity and impact not seen in several decades and has already destroyed large swaths of cropland, affecting hundreds of cities and towns across the region, and leaving ranchers struggling to feed and water cattle. Future climate projections for the area show large temperature increases and rainfall reductions, which, together with a tendency for longer periods with consecutive dry days, suggest the occurrence of more frequent/intense dry spells and droughts and a tendency toward aridification in the region. All these conditions lead to an increase in evaporation from reservoirs and lakes, affecting irrigation and agriculture as well as key water uses including hydropower and industry, and thus, the welfare of the residents. Integrating drought monitoring and seasonal forecasting provides efficient means of assessing impacts of climate variability and change, identifying vulnerabilities, and allowing for better adaptation measures not only for medium- and long-term climate change but also for extremes of the interannual climate variability, particularly droughts.

  15. PARENTAL DROUGHT AND DEFOLIATION EFFECT ON YIELD, GRAINS BIOCHEMICAL ASPECTS AND DROUGHT PERFORMANCE OF SORGHUM PROGENY

    OpenAIRE

    A.H. Ibrahim; El-Shahaby, O. A.; Abo-Hamed, S. A.; Younis, M. E.

    2013-01-01

    This study was designed to evaluate the effect of drought stress and drought with defoliation on yield parameters of three sorghum varieties (Giza 15, Dorado and Hybrid 113). Also, the effect of these parental stress treatments on drought performance of progeny of the most drought tolerant variety was investigated. Application of drought stress in the vegetative stage non significantly affected panicles number, grain yield and harvest index of all cultivars. Drought stress in the reproductive...

  16. A County-level Crop Specific Drought Severity-Coverage Index

    Science.gov (United States)

    Leelaruban, N.; Akyuz, A.; Padmanabhan, G.; Shaik, S.

    2012-12-01

    Understanding drought severity, frequency, duration and spatial extent is critical in drought mitigation, planning and decision making. A county-level approach to addressing drought is ideal since most agricultural management is best administered at county level in the USA. This study sought to apply spatiotemporal drought characteristics at reduced areal extents, namely, at county level for an entire state (North Dakota, USA) using a derived weekly non-dimensional index, Drought Severity and Coverage Index (Isc) based on a stepwise approach. Isc was calculated from weekly percentages of areal coverage values of drought intensity values published by the "U.S. Drought Monitor", DM. DM is published weekly as a joint project by the National Drought Mitigation Center (NDMC), U.S. Department of Agriculture (USDA), and the National Atmospheric and Oceanic Administration (NOAA). In order to facilitate application at the county level, the variation of the drought based on Isc was mapped in county level for state of North Dakota, and drought events were categorized into classes based on weekly Isc to analyze drought frequency. The number of occurrences of drought events were then determined for each county and climate division based on derived classes. The drought frequency analyses showed clear demarcation of counties in an observable dichotomy. Impact of drought on crop yield was also analyzed using USDA National Agricultural Statistics Service (NASS) county level yield, developed Isc values, drought intensity categories of areal coverage values for selected crops such as barley, corn, durum wheat, hay-alfalfa, hay, oats, and spring wheat. This research uses alternative panel statistical procedures instead of the usual time series analysis procedures to account for temporal and spatial variations to accurately model the relationship between exogenous and endogenous drought variables. In alternative panel procedures, two-way random effects model was used which accounts for

  17. Improving federal response to drought

    Energy Technology Data Exchange (ETDEWEB)

    Wilhite, D.A.; Rosenberg, N.J.; Glantz, M.H.

    1986-03-01

    Severe and widespread drought occurred over a large portion of the US between 1974 and 1977. Impacts on agriculture and other industries, as well as local water supplies, were substantial. The federal government responded with forty assistance programs administered by sixteen federal agencies. Assistance was provided primarily in the form of loans and grants to people, businesses and governments experiencing hardship caused by drought. The total cost of the program is estimated at $7-8 billion. Federal response to the mid-1970s drought was largely untimely, ineffective and poorly coordinated. Four recommendations are offered that, if implemented, would improve future drought assessment and response efforts: 1) reliable and timely informational products and dissemination plans; 2) improved impact assessment techniques, especially in the agricultural sector, for use by government to identify periods of enhanced risk and to trigger assistance measures; 3) administratively centralized drought declaration procedures that are well publicized and consistently applied; and 4) standby assistance measures that encourage appropriate levels of risk management by producers and that are equitable, consistent and predictable. The development of a national drought plan that incorporates these four items is recommended. Atmospheric scientists have an important role to play in the collection and interpretation of near-real time weather data for use by government decision makers.

  18. Soil water repellency in long term drought and warming experiments

    Science.gov (United States)

    Urbanek, Emilia; Emmett, Bridget; Tietema, Albert; Robinson, David

    2017-04-01

    Increased global temperatures, altered rainfall patterns and frequently occurring extreme climatic events are already observed globally as a result of the climatic changes and further increases are predicted by the climatic models. Extreme weather events such as prolonged dry spells and heat waves can significantly affect soil ecosystem functions mainly due to decrease in soil moisture. Several studies suggested an increase in soil water repellency severity and spread as a consequence of the warming and drought, however, such understanding is based on the laboratory experimentations with soil treated as a 'black box'. In this study we tested the hypothesis of increased severity of soil water repellency subjected to drought and warming under field conditions. Occurrence and severity of soil water repellency was tested in soils subjected to a long-term (10 years) climatic simulation at two upland heathland sites in Oldebroek (Netherlands) and in Clocaenog (UK)[1]. Soil plots with similar vegetation were subjected to repeated drought and warming, compared with the control plots. Drought effect was created by a rainfall exclusion using an automatic self-retracting waterproof curtains while the warming effect was made by using a self-retracting curtains reflecting infrared radiation overnight. The results available to date provide a strong indication that climatic conditions do affect the development of SWR.

  19. Effects of Chitosan Spraying on Physiological Characteristics of Ferula flabelliloba (Apiaceae Under Drought Stress

    Directory of Open Access Journals (Sweden)

    Gh. Taheri

    2016-02-01

    with different concentrations were investigated. The main objective of this study was to examine the potential benefits of chitosan by reducing damage to F. flabelliloba at the seedling stages under water-deficit conditions. Materials and Methods In order to evaluate the effects of chitosan spraying and drought stress on physiological characteristics of F. felabelliloba, a factorial experiment in a completely randomized design with three replications was conducted in laboratory. The experimental treatments included drought stress (irrigated in Field capacity, depletion of soil water content up to 35% and 65% of FC condition and foliar chitosan spray (Zero, 0.2, 0.4, 0.6 and 0.8 mg l-1. Seeds of F. flabelliloba were harvested in June-July of 2012 from natural habitat in Binalood mountain and kept in laboratory condition until the study started. F. flabelliloba seeds were germinated and grown in soils at light/dark temperature cycle of 20-16 degree centigrade and photoperiod of 16-8 h. Irrigation treatments were performed after 20 days, when seedling established and chitosan sprayed simultaneous and repeated one month later. The shoot from 60-day-old plants were taken and used for analysis the physiological parameters. Shoot dry weight was measured in oven at 70 ºC for 24 hours. Enzyme activity was determined from the extract prepared according to the method of Sairam and Saxena (2000. Catalase and Peroxidase activities were determined according to Weydert and Cullen (2010 and Superoxide dismutase activity assayed as described by Beauchamp and Fridovich (1971. Lipid peroxidation was estimated by measuring spectrophotometrically malondialdehyde (MDA content of plant based on Jiang and Hung (2001. Total phenolic content was determined according to Ebrahimzadeh and Bahramian (2009. Data from the experiment was analyzed using SPSS ver. 17 and MSTAT-C software and mean comparison was carried out using Duncan´s multiple range test at the 95% of probability. Results and

  20. Probabilistic Drought Forecasting in Southern Taiwan Using El Niño-Southern Oscillation Index

    Directory of Open Access Journals (Sweden)

    Shien-Tsung Chen

    2013-01-01

    Full Text Available This study proposes a probabilistic drought forecasting model to forecast meteorological drought in Southern Taiwan using the El Niño-Southern Oscillation (ENSO index. Meteorological drought is defined by the standardized precipitation index (SPI, and the ENSO index is El Niño sea surface temperature (SST. Two probabilistic forecasting model architectures were constructed based on the transition probabilities from El Niño SSTs to SPIs. Both model architectures forecast a one-month-ahead probability distribution for meteorological drought using different combinations of El Niño SST variables. Forecasting results showed the robustness of the probabilistic drought forecasting models. In addition, this study discussed the selection of El Niño SST variables used in the probabilistic drought forecasting model, and found that models with a single SST input outperformed those with multiple SST inputs.

  1. Expression of the Nicotiana protein kinase (NPK1) enhanced drought tolerance in transgenic maize.

    Science.gov (United States)

    Shou, Huixia; Bordallo, Patricia; Wang, Kan

    2004-05-01

    Drought is one of the most important abiotic stresses affecting the productivity of maize. Previous studies have shown that expression of a mitogen-activated protein kinase kinase kinase (MAPKKK) gene activated an oxidative signal cascade and led to the tolerance of freezing, heat, and salinity stress in transgenic tobacco. To analyse the role of activation of oxidative stress signalling in improving drought tolerance in major crops, a tobacco MAPKKK (NPK1) was expressed constitutively in maize. Results show that NPK1 expression enhanced drought tolerance in transgenic maize. Under drought conditions, transgenic maize plants maintained significantly higher photosynthesis rates than did the non-transgenic control, suggesting that NPK1 induced a mechanism that protected photosynthesis machinery from dehydration damage. In addition, drought-stressed transgenic plants produced kernels with weights similar to those under well-watered conditions, while kernel weights of drought-stressed non-transgenic control plants were significantly reduced when compared with their non-stressed counterparts.

  2. Groundwater quality surrounding Lake Texoma during short-term drought conditions

    Science.gov (United States)

    Kampbell, D.H.; An, Y.-J.; Jewell, K.P.; Masoner, J.R.

    2003-01-01

    Water quality data from 55 monitoring wells during drought conditions surrounding Lake Texoma, located on the border of Oklahoma and Texas, was compared to assess the influence of drought on groundwater quality. During the drought month of October, water table levels were three feet (0.9 m) lower compared with several months earlier under predrought climate conditions. Detection frequencies of nitrate (> 0.1 mg/l), orthophosphates (> 0.1 mg/l), chlorides (> MCL), and sulfates (> MCL) all increased during drought. Orthophosphate level was higher during drought. Largest increases in concentration were nitrate under both agriculture lands and in septic tank areas. An increase in ammonium-nitrogen was only detected in the septic tank area. The study showed that stressors such as nitrate and total salts could potentially become a health or environmental problem during drought.

  3. Risk Assessment and Zoning of Agricultural Drought Disaster in Heilongjiang Province

    Institute of Scientific and Technical Information of China (English)

    ZHENG Kai; CHEN Hong; ZHANG Li-juan; GAO Yu-hong

    2011-01-01

    In this study, we first zoned the drought degree in the years from 1971 to 2000 in Heilongjiang Province by using precipitation anomaly equation as an indicator, and analyzed the temporal distribution characteristics and laws of arid disaster in different periods. Using the method of human being habitat risk assessment, we further studied and zoned the drought disaster risk index(DDRI) of maize cultivated in 74 stations in Heilongjiang Province via GIS software. The results showed that (1) the occurrence frequency of moderate and heavy drought in Heilongjiang Province was 1970s >1990s > 1980s, and (2) the high risk area of drought disaster for maize production mainly assembled in Qiqihar and Daqing regions in west Heilongjiang Province, where agricultural drought should be highly concerned, while low risk and slight risk areas mainly distribute in middle areas and east plain areas in Heilongjiang Province. Our study provided basis for the defense of agricultural drought disaster.

  4. Probabilistic Drought Forecasting in Southern Taiwan Using El Niño-Southern Oscillation Index

    Directory of Open Access Journals (Sweden)

    Shien-Tsung Chen

    2013-01-01

    Full Text Available This study proposes a probabilistic drought forecasting model to forecast meteorological drought in Southern Taiwan using the El Niño-SouthernNiño-Southern Oscillation (ENSO index. Meteorological drought is defined by the standardized precipitation index (SPI, and the ENSO index is El NiñoNiño sea surface temperature (SST. Two probabilistic forecasting model architectures were constructed based on the transition probabilities from El NiñoNiño SSTs to SPIs. Both model architectures forecast a one-month-ahead probability distribution for meteorological drought using different combinations of El NiñoNiño SST variables. Forecasting results showed the robustness of the probabilistic drought forecasting models. In addition, this study discussed the selection of El NiñoNiño SST variables used in the probabilistic drought forecasting model, and found that models with a single SST input outperformed those with multiple SST inputs.

  5. valuation of Germination Characteristics for Hedysarum Criniferum Boiss in Alternative Temperature and Drought Stress Conditions

    Directory of Open Access Journals (Sweden)

    A. Shahbazi

    2016-05-01

    24-26 °C day-night and four drought levels (0, -2, -4, and -6 bar with three replications. According to the results, different levels of drought stress and alternative temperature had significant effects on germination percentage and germination speed of the species seeds (α=5%. The study showed that increasing temperature and drought levels leads to reducing the germination percentage and germination speed of the species. Higher germination percentage of H. criniferum seeds in different drought levels compared to alternative temperature levels of 24-26 °C indicated that this species is more sensitive to higher temperature than high levels of drought condition. Therefore, it could partly be concluded that the H. criniferum is a relatively drought resistance species.

  6. Climatic consequences of adopting drought-tolerant vegetation over Los Angeles as a response to California drought

    Science.gov (United States)

    Vahmani, P.; Ban-Weiss, G.

    2016-08-01

    During 2012-2014, drought in California resulted in policies to reduce water consumption. One measure pursued was replacing lawns with landscapes that minimize water consumption, such as drought-tolerant vegetation. If implemented at broad scale, this strategy would result in reductions in irrigation and changes in land surface characteristics. In this study, we employ a modified regional climate model to assess the climatic consequences of adopting drought-tolerant vegetation over the Los Angeles metropolitan area. Transforming lawns to drought-tolerant vegetation resulted in daytime warming of up to 1.9°C, largely due to decreases in irrigation that shifted surface energy partitioning toward higher sensible and lower latent heat flux. During nighttime, however, adopting drought-tolerant vegetation caused mean cooling of 3.2°C, due to changes in soil thermodynamic properties and heat exchange dynamics between the surface and subsurface. Our results show that nocturnal cooling effects, which are larger in magnitude and of great importance for public health during heat events, could counterbalance the daytime warming attributed to the studied water conservation strategy. A more aggressive implementation, assuming all urban vegetation was replaced with drought-tolerant vegetation, resulted in an average daytime cooling of 0.2°C, largely due to strengthened sea breeze patterns, highlighting the important role of land surface roughness in this coastal megacity.

  7. Drought in Southeastern United States

    Science.gov (United States)

    2007-01-01

    May 2007 was a record-setting month in Georgia. Typically a dry month in this southern state, May 2007 was exceptionally so, with many locations setting record-low rainfall records and some receiving no rain at all, said state climatologist David Emory Stooksbury on GeorgiaDrought.org. The lack of rain slowed plant growth, as shown in this vegetation index image. The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA's Terra satellite collected the data used to make this image between May 9 and May 24, 2007. The image shows vegetation conditions compared to average conditions observed from 2000 through 2006. Areas in which plants are more sparse or are growing more slowly than average are brown, while better-than-average growth is green. Georgia and its neighbors (South Carolina, Alabama, and Florida) are all brown, an indication that the lack of rainfall is suppressing plant growth. The gray area in southern Georgia and northern Florida shows where MODIS could not collect valid vegetation measurements, either because of clouds or smoke. In this case, the area corresponds with land that burned during this period and was probably masked by smoke. NASA image created by Jesse Allen, Earth Observatory, using data provided by Inbal Reshef, Global Agricultural Monitoring Project.

  8. Stem Xylem Characterization for Vitis Drought Tolerance.

    Science.gov (United States)

    Rustioni, Laura; Ciacciulli, Angelo; Grossi, Daniele; Brancadoro, Lucio; Failla, Osvaldo

    2016-07-06

    Together with stomatal conductance and root conductivity, the stem water reserve and transport systems could be regulatory mechanisms able to participate in the regulation of the plant water status. Lianas, such as Vitis spp., minimize the trunk support role, and stems have evolved to improve their ability in water transport. In this work, stems of 10 different Vitis species were studied in relation to their expected drought tolerance using reflectance spectroscopy. Spectra were measured before (T0) and after coloration with Sudan IV dye. The T0 spectral signature showed characteristic species features. The partial least squares (PLS) regression and the self-organizing map (SOM) neural network analysis were able to predict the expected drought tolerance score; thus, reflectance spectroscopy was demonstrated to be a useful technique for drought tolerance phenotyping. These methods could be applied for the preliminary selection of new rootstocks/cultivars. Wood composition variation appeared to be correlated with the water stress susceptibility. To clarify this relationship, the attention was focused on the wood hydrophobicity. Sudan IV is a microscopy dye traditionally used to underline suberin, waxes, and, in general, hydrophobic substances. Differences between rough and colored spectra evidenced the absorption band of Sudan IV with a maximum at 539 nm. The coloration intensity was used to develop a hydrophobicity index. The obtained values were correlated with the expected drought tolerance score. Therefore, hydrophobic compounds seem to play an important role in water use efficiency, and an hydrophobic barrier in the xylem tissue appears to be a protective mechanism against water stress.

  9. Adding the human dimension to drought: an example from Chile

    Science.gov (United States)

    Rangecroft, Sally; Van Loon, Anne; Maureira, Héctor; Rojas, Pablo; Alejandro Gutiérrez Valdés, Sergio; Verbist, Koen

    2016-04-01

    , regulations and therefore interpretation of the data and results. We will repeat the analysis done in Chile in a diverse series of case studies across the world to reflect different natural and human influences on the water cycle. This will enable an increased understanding of our influence on water resources and the feedbacks involved, which may be both positive and negative. Ultimately, this research will develop a methodology for identifying and quantifying human activities and use this information in combination with water management modeling and forecasting for effective drought early warning and risk management.

  10. Management of drought risk under global warming

    Science.gov (United States)

    Zhang, Qiang; Han, Lanying; Jia, Jianying; Song, Lingling; Wang, Jinsong

    2016-07-01

    Drought is a serious ecological problem around the world, and its impact on crops and water availability for humans can jeopardize human life. Although drought has always been common, the drought risk has become increasingly prominent because of the climatic warming that has occurred during the past century. However, it still does not comprehensively understand the mechanisms that determine the occurrence of the drought risk it poses to humans, particularly in the context of global climate change. In this paper, we summarize the progress of research on drought and the associated risk, introduce the principle of a drought "transition" from one stage to another, synthesize the characteristics of key factors and their interactions, discuss the potential effect of climatic warming on drought risk, and use this discussion to define the basic requirements for a drought risk management system. We also discuss the main measures that can be used to prevent or mitigate droughts in the context of a risk management strategy.

  11. Enhanced drought tolerance in transgenic Leymus chinensis plants with constitutively expressed wheat TaLEA3.

    Science.gov (United States)

    Wang, Lijuan; Li, Xiaofeng; Chen, Shuangyan; Liu, Gongshe

    2009-02-01

    Leymus chinensis is an important grassland perennial grass. However, its drought tolerance requires to be improved. LEA (late embryogenesis abundant) genes are believed to confer resistance to drought and water deficiency. Using Agrobacterium-mediated transformation, a wheat LEA gene, TaLEA(3), was integrated into L. chinensis. The transgenic lines showed enhanced growth ability under drought stress during which transgenic lines had increased the relative water content, leaf water potential, relative average growth rate, but decreased the malondialdehyde content compared with the non-transgenic plant. Thus, transgenic breeding is an efficient approach to enhance drought tolerance in L. chinensis.

  12. Can field populations of the enchytraeid, Cognettia sphagnetorum, adapt to increased drought stress?

    DEFF Research Database (Denmark)

    Maraldo, Kristine; Schmidt, Inger Kappel; Beier, Claus

    2008-01-01

    The ability to evolve increased drought tolerance in response to climate change was investigated in the enchytraeid, Cognettia sphagnetorum. Populations exposed to reduced precipitation or increased night time temperature for more than six years were collected in mixed Calluna/grass heathland...... was the dominant species, especially in the upper 0-3 cm, and was clearly affected by the drought treatment. C. sphagnetorum from all plots were cultured in the laboratory to rear second or third generation adults. Results showed that populations of drought treated plots had not developed an increased drought...

  13. Comparative analysis of agricultural drought monitoring based on climate and soil moisture indicators in the Huang-Huai-Hai Plain of China

    Science.gov (United States)

    Wu, J.; Zhou, H.; An, X.

    2016-12-01

    Agricultural drought is one of very common agro-meteorological disasters, having a serious threat on crop growth and production. Effective drought monitoring will aid the drought response management to reduce drought loss. Currently there has been many drought indices used for agricultural drought monitoring. Climate-based Standardized Precipitation Evapotranspiration Index (SPEI) was widely used for agricultural drought monitoring in view of its merits of simple calculation, multi-scale and with consideration of evapotranspiration. Besides, soil moisture has been recognized as the most direct indicator for monitoring agricultural drought, which provides a huge potential for monitoring due to the increase of soil moisture accessibility. Given that algorithms of both indices are different and their monitoring results also may exist the discrepancies, it is necessary to analyze their performances of both indices in agricultural drought monitoring. In this study, we chose the climate-based SPEI and soil moisture-based index (SMI) to analyze. Firstly, drought events identified by SPEI and SMI were analyzed from the perspective of drought evolution. Then the performances of SPEI and SMI were assessed through the comparison with observed drought events. Finally, vegetation change since 2000 and impact of drought on vegetation growth in Huang-Huai-Hai (HHH) Plain were explored based on MODIS NDVI data. The results show that SPEI-based drought trend agrees with SMI-based analysis, demonstrating that drought has an alleviating trend in HHH Plain in recent years. The SPEI and SMI could identify most of drought events, whereas the SMI has better performance than SPEI when it comes to drought category. The NDVI in HHH Plain shows an upward trend since 2000 and drought occurred in 2000 causes a decline in vegetation vigor. Both the SPEI and SMI are significantly correlated with NDVI anomaly, and correlation between SMI and NDVI anomaly is slightly higher than that of SPEI.

  14. Tropical Indian Ocean Variability Driving Southeast Australian Droughts

    Science.gov (United States)

    Ummenhofer, C. C.; England, M. H.; McIntosh, P. C.; Meyers, G. A.; Pook, M. J.; Risbey, J. S.; Sen Gupta, A.; Taschetto, A. S.

    2009-04-01

    Variability in the tropical Indian Ocean has widespread effects on rainfall in surrounding countries, including East Africa, India and Indonesia. The leading mode of tropical Indian Ocean variability, the Indian Ocean Dipole (IOD), is a coupled ocean-atmosphere mode characterized by sea surface temperature (SST) anomalies of opposite sign in the east and west of the basin with an associated large-scale atmospheric re-organisation. Earlier work has often focused on the positive phase of the IOD. However, we show here that the negative IOD phase is an important driver of regional rainfall variability and multi-year droughts. For southeastern Australia, we show that it is actually a lack of the negative IOD phase, rather than the positive IOD phase or Pacific variability, that provides the most robust explanation for recent drought conditions. Since 1995, a large region of Australia has been gripped by the most severe drought in living memory, the so-called "Big Dry". The ramifications for affected regions are dire, with acute water shortages for rural and metropolitan areas, record agricultural losses, the drying-out of two of Australia's major river systems and far-reaching ecosystem damage. Yet the drought's origins have remained elusive. For Southeast Australia, we show that the "Big Dry" and other iconic 20th Century droughts, including the Federation Drought (1895-1902) and World War II drought (1937-1945), are driven by tropical Indian Ocean variability, not Pacific Ocean conditions as traditionally assumed. Specifically, a conspicuous absence of characteristic Indian Ocean temperature conditions that are conducive to enhanced tropical moisture transport has deprived southeastern Australia of its normal rainfall quota. In the case of the "Big Dry", its unprecedented intensity is also related to recent above-average temperatures. Implications of recent non-uniform warming trends in the Indian Ocean and how that might affect ocean characteristics and climate in

  15. Characterization of Drought and Its Assessment over Sindh, Pakistan During 1951-2010

    Science.gov (United States)

    Adnan, Shahzada

    2016-07-01

    Drought is one of the complex meteorological disasters, which can affect water resources, agriculture, livestock, and socioeconomic patterns of a region. Although drought prediction is difficult, it can be monitored based on climatological information. In this study, we provide high spatial and temporal resolution drought climatology, using observational, gridded precipitation data (0.5°X 0.5°) from the Global Precipitation Climatological Center and soil moisture from the Climate Prediction Centre for the 60-yr period 1951-2010. The standardized precipitation index (SPI) based on a fitted Gamma distribution and Run Method has been calculated from the regional drought identification model (ReDIM) on 3, 6, 9, 12 and 24 months. The results show strong temporal correlations among anomalies of precipitation, soil moisture, and SPI. Analysis of long-term precipitation data reveals that the drought vulnerability concentrates on monsoon season (July-September), which contributes 72.4% and 82.1% of annual precipitation in northern and southern Sindh, respectively. Annual and seasonal analyses show no significant changes in the observed precipitation. The category classification criteria are defined to monitor/forecast drought in the selected area. Further analysis identifies two longest episodes of drought, i.e., 1972-1974 and 2000-2002, while 1969, 1974, 1987, and 2002 are found to be the most severe historical drought years. A drought hazard map of Sindh was developed, in which 10 districts are recognized as highly vulnerable to drought. This study helps in explaining the time, duration, intensity, and frequency of meteorological droughts over Sindh as well as its neighboring regions, and provides useful information to disaster management agencies and forecasters for assessing both the regional vulnerability of drought and its seasonal predictability in Pakistan.

  16. Evaluation of soil moisture and Palmer Drought Severity Index in Brazil

    Science.gov (United States)

    Rossato, Luciana; Antônio Marengo, José; Bassi Marinho Pires, Luciana

    2016-04-01

    Soil moisture is one of the main factors for the study of drought, climate and vegetation. In the case of drought, this is a regional phenomenon and affects food security more than any other natural disaster. Therefore, monitoring of different types of drought has been based on indexes that standardize on temporal and spatial scales. Currently, the monitoring of different types of drought is based on indexes that attempt to encapsulate on temporal and regional levels allowing thereby the comparison of water conditions in different areas. Therefore, in order to assess the impact of soil moisture during periods of drought, the Palmer Drought Severity Index was estimated for the entire Brazilian territory, using meteorological (precipitation and evapotranspiration) and soil (field capacity, permanent wilting point and water storage in the soil) data. The data field capacity and permanent wilting point were obtained from the physical properties of the soil, while the water storage in the soil was calculated considering the water balance model. Analyses were made for the years 2000 through 2014, which includes periods with and without occurrence of drought, respectively. The results showed that the PDSI had higher negative indices for the years 2003 and 2012 in Brazil's Northeast region, and this region was strongly affected by drought during those years. These indices can serve as a basis for assessing future drought projections, considering different scenarios. The results also show that soil moisture constitutes one of the limiting factors for obtaining high agricultural productivity, in order to reduce the effects caused by drought. Therefore, these indices can serve as a basis for assessing future drought projections, considering different scenarios. It would be desirable to assist decision makers in action plans with more effective strategies, allowing farmers to live with drought without losing their livelihood.

  17. Disruption of hydroecological equilibrium in southwest Amazon mediated by drought

    Science.gov (United States)

    Maeda, Eduardo Eiji; Kim, Hyungjun; Aragão, Luiz E. O. C.; Famiglietti, James S.; Oki, Taikan

    2015-09-01

    The impacts of droughts on the Amazon ecosystem have been broadly discussed in recent years, but a comprehensive understanding of the consequences is still missing. In this study, we show evidence of a fragile hydrological equilibrium in the western Amazon. While drainage systems located near the equator and the western Amazon do not show water deficit in years with average climate conditions, this equilibrium can be broken during drought events. More importantly, we show that this effect is persistent, taking years until the normal hydrological patterns are reestablished. We show clear links between persistent changes in forest canopy structure and changes in hydrological patterns, revealing physical evidence of hydrological mechanisms that may lead to permanent changes in parts of the Amazon ecosystem. If prospects of increasing drought frequency are confirmed, a change in the current hydroecological patterns in the western Amazon could take place in less than a decade.

  18. Conditional Copula-Based Spatial–Temporal Drought Characteristics Analysis—A Case Study over Turkey

    Directory of Open Access Journals (Sweden)

    Mahdi Hesami Afshar

    2016-10-01

    Full Text Available In this study, commonly used copula functions belonging to Archimedean and Elliptical families are fitted to the univariate cumulative distribution functions (CDF of the drought characteristics duration ( LD , average severity ( S ¯ , and average areal extent ( A ¯ of droughts obtained using standardized precipitation index (SPI between 1960 and 2013 over Ankara, Turkey. Probabilistic modeling of drought characteristics with seven different fitted copula functions and their comparisons with independently estimated empirical joint distributions show normal copula links drought characteristics better than other copula functions. On average, droughts occur with an average LD of 6.9 months, S ¯ of 0.94, and A ¯ of 73%, while such a drought event happens on average once in every 6.65 years. Results also show a very strong and statistically significant relation between S ¯ and A ¯ , and drought return periods are more sensitive to the unconditioned drought characteristic, while return periods decrease by adding additional variables to the analysis (i.e., trivariate drought analysis compared to bivariate.

  19. Drought impacts on vegetation activity in the Mediterranean region: An assessment using remote sensing data and multi-scale drought indicators

    Science.gov (United States)

    Gouveia, C. M.; Trigo, R. M.; Beguería, S.; Vicente-Serrano, S. M.

    2017-04-01

    The present work analyzes the drought impacts on vegetation over the entire Mediterranean basin, with the purpose of determining the vegetation communities, regions and seasons at which vegetation is driven by drought. Our approach is based on the use of remote sensing data and a multi-scalar drought index. Correlation maps between fields of monthly Normalized Difference Vegetation Index (NDVI) and the Standardized Precipitation-Evapotranspiration Index (SPEI) at different time scales (1-24 months) were computed for representative months of winter (Feb), spring (May), summer (Aug) and fall (Nov). Results for the period from 1982 to 2006 show large areas highly controlled by drought, although presenting high spatial and seasonal differences, with a maximum influence in August and a minimum in February. The highest correlation values are observed in February for 3 months' time scale and in May for 6 and 12 months. The higher control of drought on vegetation in February and May is obtained mainly over the drier vegetation communities (Mediterranean Dry and Desertic) at shorter time scales (3 to 9 months). Additionally, in February the impact of drought on vegetation is lower for Temperate Oceanic and Continental vegetation types and takes place at longer time scales (18-24). The dependence of drought time-scale response with water balance, as obtained through a simple difference between precipitation and reference evapotranspiration, varies with vegetation communities. During February and November low water balance values correspond to shorter time scales over dry vegetation communities, whereas high water balance values implies longer time scales over Temperate Oceanic and Continental areas. The strong control of drought on vegetation observed for Mediterranean Dry and Desertic vegetation types located over areas with high negative values of water balance emphasizes the need for an early warning drought system covering the entire Mediterranean basin. We are confident

  20. Analysis of Drought in Poyang Lake

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    [Objective] The drought situation and causes in Poyang Lake were analyzed.[Method] In response to the drought in Poyang Lake in ten years ago and in recent 10 years,the causes of drought in Poyang Lake were discussed.[Result] Drought occurred frequently in Poyang Lake and the consecutive serious drought occurred now and then.The water level in Poyang Lake since 21st century was lower.The drought in Poyang Lake was due to reduction of precipitation,low water level in Yangtze River and "five lakes",hydraulic ...

  1. Reconstructing and analyzing China's fifty-nine year (1951–2009 drought history using hydrological model simulation

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    Z. Y. Wu

    2011-02-01

    Full Text Available The recent fifty-nine year (1951–2009 drought history of China is reconstructed using daily soil moisture values generated by the Variable Infiltration Capacity (VIC land surface macroscale hydrology model. VIC is applied over a grid of 10 458 points with a spatial resolution of 30 km × 30 km, and is driven by observed daily maximum and minimum air temperature and precipitation from 624 long-term meteorological stations. The VIC soil moisture is used to calculate the Soil Moisture Anomaly Percentage Index (SMAPI, which can be used as a measure of the severity of agricultural drought on a global basis. We develop a SMAPI-based drought identification procedure for practical uses in the identification of both grid point and regional drought events. As the result, a total of 325 regional drought events varying in time and strength are identified from China's nine drought study regions. These drought events can thus be assessed quantitatively at different spatial and temporal scales. The result shows that the severe drought events of 1978, 2000 and 2006 are well reconstructed, indicating SMAPI is capable of indentifying the onset of a drought event, its progressing, as well as its ending. Spatial and temporal variations of droughts on China's nine drought study regions are studied. Our result shows that on average, up to 30% of the total area of China is prone to drought. Regionally, an upward trend in drought-affected areas has been detected in three regions Inner Mongolia, Northeast and North during the recent fifty-nine years. However, the decadal variability of droughts has been week in the rest five regions South, Southwest, East, Northwest, and Tibet. Xinjiang has even been wetting steadily since the 1950s. Two regional dry centers are discovered in China as the result of a combined analysis on the occurrence of drought events from both grid points and drought study regions. The first center is located in the area partially covered by two

  2. Proteomic responses of drought-tolerant and drought-sensitive cotton varieties to drought stress.

    Science.gov (United States)

    Zhang, Haiyan; Ni, Zhiyong; Chen, Quanjia; Guo, Zhongjun; Gao, Wenwei; Su, Xiujuan; Qu, Yanying

    2016-06-01

    Drought, one of the most widespread factors reducing agricultural crop productivity, affects biological processes such as development, architecture, flowering and senescence. Although protein analysis techniques and genome sequencing have made facilitated the proteomic study of cotton, information on genetic differences associated with proteomic changes in response to drought between different cotton genotypes is lacking. To determine the effects of drought stress on cotton seedlings, we used two-dimensional polyacrylamide gel electrophoresis (2-DE) and matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry to comparatively analyze proteome of drought-responsive proteins during the seedling stage in two cotton (Gossypium hirsutum L.) cultivars, drought-tolerant KK1543 and drought-sensitive Xinluzao26. A total of 110 protein spots were detected on 2-DE maps, of which 56 were identified by MALDI-TOF and MALDI-TOF/TOF mass spectrometry. The identified proteins were mainly associated with metabolism (46.4 %), antioxidants (14.2 %), and transport and cellular structure (23.2 %). Some key proteins had significantly different expression patterns between the two genotypes. In particular, 5-methyltetrahydropteroyltriglutamate-homocysteine methyltransferase, UDP-D-glucose pyrophosphorylase and ascorbate peroxidase were up-regulated in KK1543 compared with Xinluzao26. Under drought stress conditions, the vacuolar H(+)-ATPase catalytic subunit, a 14-3-3g protein, translation initiation factor 5A and pathogenesis-related protein 10 were up-regulated in KK1543, whereas ribosomal protein S12, actin, cytosolic copper/zinc superoxide dismutase, protein disulfide isomerase, S-adenosylmethionine synthase and cysteine synthase were down-regulated in Xinluzao26. This work represents the first characterization of proteomic changes that occur in response to drought in roots of cotton plants. These differentially expressed proteins may be related to

  3. Exploring drought stress-regulated genes in senna (Cassia angustifolia Vahl.): a transcriptomic approach.

    Science.gov (United States)

    Mehta, Rucha Harishbhai; Ponnuchamy, Manivel; Kumar, Jitendra; Reddy, Nagaraja Reddy Rama

    2017-01-01

    De novo assembly of reads produced by next-generation sequencing (NGS) technologies offers a rapid approach to obtain expressed gene sequences for non-model organisms. Senna (Cassia angustifolia Vahl.) is a drought-tolerant annual undershrub of Caesalpiniaceae, a subfamily of Fabaceae. There are insufficient transcriptomic and genomic data in public databases for understanding the molecular mechanism underlying the drought tolerance of senna. Therefore, the main purpose of this study was to know the transcriptome profile of senna, with special reference to drought stress. RNA from two different stages of leaf development was extracted and sequenced separately using the Illumina technology. A total of 200 million reads were generated, and a de novo assembly of processed reads in the pooled transcriptome using Trinity yielded 43,413 transcripts which were further annotated using NCBI BLAST with "green plant database (txid 33090)," Swiss Prot, Kyoto Encyclopedia of Genes and Genomes (KEGG), Clusters of Orthologous Groups (COG), and Gene Ontology (GO). Out of the total transcripts, 42,280 (95.0 %) were annotated by BLASTX against the green plant database of NCBI. Senna transcriptome showed the highest similarity to Glycine max (41 %), followed by Phaseolus vulgaris (16 %), Cicer arietinum (15 %), and Medicago trancatula (5 %). The highest number of GO terms were enriched for the molecular functions category; of these "catalytic activity" (GO: 0003824) (25.10 %) and "binding activity" (GO: 0005488) (20.10 %) were most abundantly represented. We used InterProscan to see protein similarity at domain level; a total of 33,256 transcripts were annotated against the Pfam domains. The transcripts were assigned with various KEGG pathways. Coding DNA sequences (CDS) encoding various drought stress-regulated pathways such as signaling factors, protein-modifying/degrading enzymes, biosynthesis of phytohormone, phytohormone signaling, osmotically active compounds, free radical

  4. Study and evaluation of drought resistance of different genotype maize inbred lines

    Institute of Scientific and Technical Information of China (English)

    Weixing ZHANG; Zhi ZHAO; Guangxiao BAI; Fangjing FU

    2008-01-01

    Using cultivating experiments in fields under drought stress, yields and characteristics in morphology, growth and development of different genotype maize inbred lines were studied systematically. We evaluated and classified the drought resistance of these materials based on the needed indexes, including subordinate func-tion values of drought resistance (SV), drought coefficient (DC) and drought index (DI) of yield by fuzzy function method and cluster analysis. We also analyzed the corre-lations between parameters and tested values of traits. The effective parameters and indexes of comprehensive evalu-ation for drought resistance were selected with principal component analysis. The results showed that under drought stress, the yield of maize inbred lines obviously decreased. The anthesis and silking interval (ASI) was prolonged compared with the control, with a smaller leaf area, thinner stalk, shorter and smaller ears, lengthened barren ear tip, a decline in plant height and ear position, reduced grain number per ear and grain weight, which led to a yield decline. Effects of drought treatment on differ-ent maize inbred lines were significantly different. 79-1E, Jiao51, Su1-1 and 18599 were found to be highly resistant to drought, while 1125 and 5311 performed the worst. DI and SV were significantly correlated with drought resist-ance. Our results indicated that DI, SV, yield and leaf area could be used as parameters and indexes to effectively evaluate the drought resistance of maize. Meanwhile, DC, plant height, ASI, grain number per ear or row, ear length and diameter could be taken as auxiliary para-meters and indexes. An applied scientific method for the comprehensive evaluation of drought resistance was offered in this paper.

  5. Response of vegetation to drought time-scales across global land biomes.

    Science.gov (United States)

    Vicente-Serrano, Sergio M; Gouveia, Célia; Camarero, Jesús Julio; Beguería, Santiago; Trigo, Ricardo; López-Moreno, Juan I; Azorín-Molina, César; Pasho, Edmond; Lorenzo-Lacruz, Jorge; Revuelto, Jesús; Morán-Tejeda, Enrique; Sanchez-Lorenzo, Arturo

    2013-01-02

    We evaluated the response of the Earth land biomes to drought by correlating a drought index with three global indicators of vegetation activity and growth: vegetation indices from satellite imagery, tree-ring growth series, and Aboveground Net Primary Production (ANPP) records. Arid and humid biomes are both affected by drought, and we suggest that the persistence of the water deficit (i.e., the drought time-scale) could be playing a key role in determining the sensitivity of land biomes to drought. We found that arid biomes respond to drought at short time-scales; that is, there is a rapid vegetation reaction as soon as water deficits below normal conditions occur. This may be due to the fact that plant species of arid regions have mechanisms allowing them to rapidly adapt to changing water availability. Humid biomes also respond to drought at short time-scales, but in this case the physiological mechanisms likely differ from those operating in arid biomes, as plants usually have a poor adaptability to water shortage. On the contrary, semiarid and subhumid biomes respond to drought at long time-scales, probably because plants are able to withstand water deficits, but they lack the rapid response of arid biomes to drought. These results are consistent among three vegetation parameters analyzed and across different land biomes, showing that the response of vegetation to drought depends on characteristic drought time-scales for each biome. Understanding the dominant time-scales at which drought most influences vegetation might help assessing the resistance and resilience of vegetation and improving our knowledge of vegetation vulnerability to climate change.

  6. Estimation of Variability Characteristics of Regional Drought during 1964–2013 in Horqin Sandy Land, China

    Directory of Open Access Journals (Sweden)

    Yongfang Wang

    2016-11-01

    Full Text Available Drought has an important influence on the hydrological cycle, ecological system, industrial and agricultural production, and social life. Based on the different time scales of characteristics of drought variability, the standardized precipitation evapotranspiration index (SPEI, a multi-timescale index with consideration of evaporation, was used in this study to estimate the spatial and temporal variability characteristics of drought. Climatic data from 15 meteorological stations across Horqin Sandy Land during 1964–2013 were used to calculate the SPEI of 1, 3, 6, and 12 months. In order to examine the relationship between droughts and other variables, 10 extreme climate indices were calculated based on the daily precipitation and maximum/mean/minimum temperature data of 15 meteorological stations, and linkages between SPEI-12 and atmosphere indices were established using by the cross wavelet transform method. The results indicated that the climate of Horqin Sandy Land had a tendency towards drought conditions, which is particularly apparent from the year 2000 onwards. During the study period, drought events were frequent in the region. Mild drought occurred in a quarter of the month, with that of moderate, severe, and extreme drought accounting for 0.11, 0.05, and 0.02 of the total months. The spatial trend of multi-timescale drought revealed that there was an increase in the severity of drought throughout Horqin Sandy Land, among which the magnitude in southern parts was larger than that of northern parts. The results also showed that the short time scale drought negatively correlated with precipitation extremes and positively correlated with temperature extremes. Furthermore, the long time scale drought (SPEI-12 was associated with atmosphere indices. Significant resonance periods were found between El Nino southern oscillation (ENSO, the East Asian summer monsoon index (EASMI, and SPEI-12.

  7. A multiscale analysis of drought and pluvial mechanisms for the Southeastern United States

    Science.gov (United States)

    Kam, Jonghun; Sheffield, Justin; Wood, Eric F.

    2014-06-01

    The Southeast (SE) U.S. has experienced several severe droughts over the past 30 years, with the most recent drought during 2006-2008 causing agricultural impacts of $1 billion. However, the mechanisms that lead to droughts over the region and their persistence have been poorly understood due to the region's humid coastal environment and its complex climate. In this study, we carry out a multiscale analysis of drought mechanisms for the SE U.S. over 1979-2008 using the North American Regional Reanalysis (NARR) to identify conditions associated with drought and contrast with those associated with pluvials. These conditions include land surface drought propagation, land-atmosphere feedbacks, regional moisture sources, persistent atmospheric patterns, and larger-scale oceanic conditions. Typical conditions for SE U.S. droughts (pluvials) are identified as follows: (1) weaker (stronger) southerly meridional fluxes and weaker (stronger) westerly zonal fluxes, (2) strong moisture flux divergence (convergence) by transient eddies, and (3) strong (weak) coupling between the land surface and atmosphere. The NARR demonstrates that historic SE droughts are mainly derived from a combination of a strong North Atlantic subtropical high (NASH) and Icelandic Low (IL) during summer and winter, respectively, which peak 1 month earlier than the onset of the drought. The land surface plays a moderate role in drought occurrence over the SE via recycling of precipitation, and the oceans show an asymmetric influence on droughts and pluvials depending on the season. This study suggests that the NASH and IL can be used as a predictor for SE droughts at 1 month lead despite the overall that it represents an atmospheric forcing.

  8. Assessment of agricultural drought in rainfed cereal production areas of northern China

    Science.gov (United States)

    Li, Rui; Tsunekawa, Atsushi; Tsubo, Mitsuru

    2017-02-01

    Agricultural drought assessment is an important tool for water management in water-scarce regions such as Inner Mongolia and northeastern China. Conventional methods have difficulty of clarifying long-term influences of drought on regional agricultural production. To accurately evaluate regional agricultural drought, we assessed the performance of drought indices by constructing a new assessment framework with three components: crop model calibration and validation, drought index calculation, and index assessment (standard period setting, mean value and agreement assessments). The Environmental Policy Integrated Climate (EPIC) model simulated well of county-level wheat and maize yields in the nine investigated counties. We calculated a major crop-specific index yield reduction caused by water stress (WSYR) in the EPIC crop model, by relating potential and rainfed yields. Using 26 agricultural drought cases, we compared WSYR with two meteorological drought indices: precipitation (P) and aridity index (AI). The results showed that WSYR had greater agreement (85 %) than either the precipitation (65 %) or aridity index (68 %). The temporal trend of the indices over the period 1962-2010 was tested using three approaches. The result via WSYR revealed a significant increase in the trend of agricultural drought in drought-prone counties, which could not be shown by the precipitation and aridity indices. Total number of dry year via WSYR from 1990s to 2000s increases more sharply than via P or AI. As shown by WSYR, the number of dry years in northeastern China and Inner Mongolia is generally increasing, particularly after the 2000s, in the western part of the study area. The study reveals the usefulness of the framework for drought index assessment and indicates the potential of WSYR and possible drought cases for drought classification.

  9. Spatio-temporal variation of drought in China during 1961-2012: A climatic perspective

    Science.gov (United States)

    Xu, Kai; Yang, Dawen; Yang, Hanbo; Li, Zhe; Qin, Yue; Shen, Yan

    2015-07-01

    Understanding the spatial and temporal variation of drought is essentially important in drought assessment. In most previous studies, drought event is usually identified in space and time separately, ignoring the nature of the dynamic processes. In order to better understand how drought changes have taken place in China during the past half-century, we carried out a comprehensive analysis of their spatio-temporal variation based on multiple drought indices from a climatic perspective. A 3-dimensional clustering method is developed to identify drought events in China from 1961 to 2012 based on the 0.25° gridded indices of SPI3 (3 months Standardized Precipitation Index), RDI3 (3 months Reconnaissance Drought Index) and SPEI3 (3 months Standardized Precipitation Evapotranspiration Index). Drought events are further characterized by five parameters: duration, affected area, severity, intensity, and centroid. Remotely sensed soil moisture data were used to validate the rationality of identified drought events. The results show that the two most severe drought events in the past half century which occurred in the periods 1962-1963 and 2010-2011 swept more than half of the non-arid regions in China. Large magnitude droughts were usually centered in the region from North China Plain to the downstream of Yangtze River. The western part of North China Plain, Loess Plateau, Sichuan Basin and Yunnan-Guizhou Plateau had a significant drying trend, which is mainly caused by the significant decrease of precipitation. The three drought indices have almost the same performance in the humid regions, while SPI and RDI were found to be more appropriate than SPEI in the arid regions.

  10. Assessment of agricultural drought in rainfed cereal production areas of northern China

    Science.gov (United States)

    Li, Rui; Tsunekawa, Atsushi; Tsubo, Mitsuru

    2015-10-01

    Agricultural drought assessment is an important tool for water management in water-scarce regions such as Inner Mongolia and northeastern China. Conventional methods have difficulty of clarifying long-term influences of drought on regional agricultural production. To accurately evaluate regional agricultural drought, we assessed the performance of drought indices by constructing a new assessment framework with three components: crop model calibration and validation, drought index calculation, and index assessment (standard period setting, mean value and agreement assessments). The Environmental Policy Integrated Climate (EPIC) model simulated well of county-level wheat and maize yields in the nine investigated counties. We calculated a major crop-specific index yield reduction caused by water stress (WSYR) in the EPIC crop model, by relating potential and rainfed yields. Using 26 agricultural drought cases, we compared WSYR with two meteorological drought indices: precipitation (P) and aridity index (AI). The results showed that WSYR had greater agreement (85 %) than either the precipitation (65 %) or aridity index (68 %). The temporal trend of the indices over the period 1962-2010 was tested using three approaches. The result via WSYR revealed a significant increase in the trend of agricultural drought in drought-prone counties, which could not be shown by the precipitation and aridity indices. Total number of dry year via WSYR from 1990s to 2000s increases more sharply than via P or AI. As shown by WSYR, the number of dry years in northeastern China and Inner Mongolia is generally increasing, particularly after the 2000s, in the western part of the study area. The study reveals the usefulness of the framework for drought index assessment and indicates the potential of WSYR and possible drought cases for drought classification.

  11. UAV remote sensing for phenotyping drought tolerance in peanuts

    Science.gov (United States)

    Balota, Maria; Oakes, Joseph

    2017-05-01

    crop value in particular when taken on the ground at 15 days water stress imposition. Interestingly, CT predicted well plant wilting even before it occurred, i.e., correlation coefficients were negative and over 0.750 when CT was measured on July 19 and 20 even though wilting was visible only after two weeks. The data, yet preliminary, show promising potential for remote sensing technologies, at the ground and aerial, for peanut variety selection for improved drought tolerance.

  12. Assessing existing drought monitoring and forecasting capacities, mitigation and adaptation practices in Africa

    Science.gov (United States)

    Nyabeze, W. R.; Dlamini, L.; Lahlou, O.; Imani, Y.; Alaoui, S. B.; Vermooten, J. S. A.

    2012-04-01

    Drought is one of the major natural hazards in many parts of the world, including Africa and some regions in Europe. Drought events have resulted in extensive damages to livelihoods, environment and economy. In 2011, a consortium consisting of 19 organisations from both Africa and Europe started a project (DEWFORA) aimed at developing a framework for the provision of early warning and response through drought impact mitigation for Africa. This framework covers the whole chain from monitoring and vulnerability assessment to forecasting, warning, response and knowledge dissemination. This paper presents the first results of the capacity assessment of drought monitoring and forecasting systems in Africa, the existing institutional frameworks and drought mitigation and adaptation practices. Its focus is particularly on the historical drought mitigation and adaptation actions identified in the North Africa - Maghreb Region (Morocco, Algeria and Tunisia) and in the Southern Africa - Limpopo Basin. This is based on an extensive review of historical drought experiences. From the 1920's to 2009, the study identified 37 drought seasons in the North African - Maghreb Region and 33 drought seasons in the Southern Africa - Limpopo Basin. Existing literature tends to capture the spatial extent of drought at national and administrative scale in great detail. This is driven by the need to map drought impacts (food shortage, communities affected) in order to inform drought relief efforts (short-term drought mitigation measures). However, the mapping of drought at catchment scale (hydrological unit), required for longer-term measures, is not well documented. At regional level, both in North Africa and Southern Africa, two organisations are involved in drought monitoring and forecasting, while at national level 22 organisations are involved in North Africa and 37 in Southern Africa. Regarding drought related mitigation actions, the inventory shows that the most common actions

  13. Drought tolerance in modern and wild wheat.

    Science.gov (United States)

    Budak, Hikmet; Kantar, Melda; Kurtoglu, Kuaybe Yucebilgili

    2013-01-01

    The genus Triticum includes bread (Triticum aestivum) and durum wheat (Triticum durum) and constitutes a major source for human food consumption. Drought is currently the leading threat on world's food supply, limiting crop yield, and is complicated since drought tolerance is a quantitative trait with a complex phenotype affected by the plant's developmental stage. Drought tolerance is crucial to stabilize and increase food production since domestication has limited the genetic diversity of crops including wild wheat, leading to cultivated species, adapted to artificial environments, and lost tolerance to drought stress. Improvement for drought tolerance can be achieved by the introduction of drought-grelated genes and QTLs to modern wheat cultivars. Therefore, identification of candidate molecules or loci involved in drought tolerance is necessary, which is undertaken by "omics" studies and QTL mapping. In this sense, wild counterparts of modern varieties, specifically wild emmer wheat (T. dicoccoides), which are highly tolerant to drought, hold a great potential. Prior to their introgression to modern wheat cultivars, drought related candidate genes are first characterized at the molecular level, and their function is confirmed via transgenic studies. After integration of the tolerance loci, specific environment targeted field trials are performed coupled with extensive analysis of morphological and physiological characteristics of developed cultivars, to assess their performance under drought conditions and their possible contributions to yield in certain regions. This paper focuses on recent advances on drought related gene/QTL identification, studies on drought related molecular pathways, and current efforts on improvement of wheat cultivars for drought tolerance.

  14. Exploration of diffusion kernel density estimation in agricultural drought risk analysis: a case study in Shandong, China

    Directory of Open Access Journals (Sweden)

    W. Chen

    2015-11-01

    Full Text Available Drought caused the most widespread damage in China, making up over 50 % of the total affected area nationwide in recent decades. In the paper, a Standardized Precipitation Index-based (SPI-based drought risk study is conducted using historical rainfall data of 19 weather stations in Shandong province, China. Kernel density based method is adopted to carry out the risk analysis. Comparison between the bivariate Gaussian kernel density estimation (GKDE and diffusion kernel density estimation (DKDE are carried out to analyze the effect of drought intensity and drought duration. The results show that DKDE is relatively more accurate without boundary-leakage. Combined with the GIS technique, the drought risk is presented which reveals the spatial and temporal variation of agricultural droughts for corn in Shandong. The estimation provides a different way to study the occurrence frequency and severity of drought risk from multiple perspectives.

  15. Changes in Drought Conditions in Poland over the Past 60 Years Evaluated by the Standardized Precipitation-Evapotranspiration Index

    Science.gov (United States)

    Somorowska, Urszula

    2016-12-01

    This paper investigates the variability of drought conditions in Poland in the years 1956-2015 with the use of the Standardized Precipitation-Evapotranspiration Index (SPEI). The study provides a new insight into the phenomenon of the past expansion of the drought-affected area as well as evidence of drying trends in a spatiotemporal context. 3-month, 6-month, and 12-month SPEI were considered, representing drought conditions relevant to agriculture and hydrology. The analysis demonstrates that the spatial extent of droughts shows a broad variability. The annual mean of the percentage of the area under drought has witnessed an increase for all three SPEI timescales. This also pertains to the mean area affected by drought over the growing season (April-September). A decreasing trend in the SPEI values indicates an increase in the severity of droughts over the 60-year period in question in an area extending from the south-west to the central part of Poland.

  16. Evolution of drought severity and its impact on corn in the Republic of Moldova

    Science.gov (United States)

    Potop, Vera

    2011-10-01

    Droughts in Moldova were evaluated using meteorological data since 1955 and a long time series (1891-2009). In addition, yields for corn ( Zea mays L.), a crop widely grown in Moldova, were used to demonstrate drought impact. The main aim is to propose use of the S i ( S i-a and S i-m) drought index while discussing its potential use in studying the evolution of drought severity in Moldova. Also, a new multi-scalar drought index, the standardized precipitation-evapotranspiration index (SPEI), is tested for the first time in identifying drought variability in Moldova while comparing it with the commonly used standardized precipitation index (SPI). S i-m, SPI, SPEI, and S i-a indices show an increasing tendency toward more intensive and prolonged severely dry and extremely dry summer months. Drought frequency increased through six decades, which included long dry periods in the 1990s and 2000s. Moreover, the evolution of summer evapotranspiration recorded a positive and significant trend (+3.3 mm/year, R 2 = 0.46; p ≤ 0.05) between 1955 and 2009. A yield model based on the S i-a agricultural index and historic corn yields explained 43% of observed variability in corn production when drought occurred in May, July, and August. Increasing severity of the 20-year drought during the critical part of the growing season is raising corn yield losses, as net losses have so far exceeded net gains.

  17. Rice Breeding for High Grain Yield under Drought: A Strategic Solution to a Complex Problem

    Directory of Open Access Journals (Sweden)

    Shalabh Dixit

    2014-01-01

    Full Text Available Drought is one of the major abiotic stresses that affect rice production in rainfed areas. Recent trends in climate change have predicted a further increase in drought intensity, making the development of new drought-tolerant rice cultivars critical to sustain rice production in this ecosystem. The use of grain yield as a selection criterion at the International Rice Research Institute (IRRI, through proper population development and precise phenotyping techniques, has allowed the development of several high-yielding rice cultivars that have been released in major rainfed rice-growing areas. This strategy has also allowed the identification of several major quantitative trait loci (QTLs that show large effects under drought across environments and genetic backgrounds. These QTLs are being pyramided together to develop drought-tolerant versions of popular drought-susceptible varieties. The near-isogenic lines (NILs developed can replace the popular, high-yielding but drought-susceptible varieties in rainfed areas prone to drought. Additionally, these NILs serve as suitable genetic material for the study of molecular and physiological mechanisms underlying these QTLs. This may provide a better understanding of plant functions responsible for high grain yield under drought and lead to the identification of new traits and genes.

  18. Adaptation to drought in arid and semi-arid environments: Case of the Zambezi Valley, Zimbabwe

    Directory of Open Access Journals (Sweden)

    Emmanuel Mavhura

    2015-02-01

    Full Text Available Small-scale rain-fed agriculture is the main livelihood in arid to semi-arid regions of subSaharan Africa. The area is characterised by erratic rainfall and frequent droughts, making the capacity for coping with temporal water shortages essential for smallholder farmers. Focusing on the Zambezi Valley, Zimbabwe, this study investigates the impact of drought on food security and the strategies used by smallholder farmers to cope with drought. We used meteorological data and interviews to examine the rainfall variability in the study area and the drought-coping mechanisms employed by smallholder famers respectively. The results show that there are various strategies used by smallholder farmers to cope with the impact of drought. These strategies include drought-tolerant crop production, crop variety diversification, purchasing cereals through asset sales, non-governmental organisations’ food aid and gathering wild fruit. However, consecutive droughts have resulted in high food insecurity and depletion of household assets during droughts. Smallholder farmers in the valley have also resorted to a number of measures taken before, during and after the drought. Still, these strategies are not robust enough to cope with this uncertainty

  19. Identification of differentially expressed genes under drought stress in perennial ryegrass.

    Science.gov (United States)

    Liu, Shuwei; Jiang, Yiwei

    2010-08-01

    Perennial ryegrass (Lolium perenne L.) is a widely used cool-season forage and turf grass species. Drought stress can significantly affect the growth and development of grass plants. Identification of genes involved in drought tolerance facilitates genetic improvement of perennial ryegrass. A forward and a reverse cDNA library were constructed in drought-tolerant (PI 440474) and drought-susceptible (PI 204085) accessions by using suppression subtractive hybridization (SSH). A BLAST search revealed that 95 of 256 expressed sequence tags (ESTs) obtained from the two libraries showed significant sequence homologies to genes with known functions. They were classified into different putative functional groups including amino acid metabolism, lipid metabolism, carbohydrate metabolism, transcription, protein synthesis and destination, energy, photosynthesis, signal transduction, cellular transport and detoxification. Among them, 50 ESTs were from forward library (the drought tolerant over the susceptible accession). The expression patterns (reverse transcriptase polymerase chain reaction) of the selected genes encoding mitogen-activated protein kinase, superoxide dismutase and glutathione peroxidase (GPX) in additional accessions contrasting in drought tolerance were generally consistent with patterns of differentially expressed genes identified through SSH. The GPX fragment had a high degree of nucleotide diversity (pi = 0.0251) in the selected perennial ryegrass accessions. The results suggest that differentially expressed genes between drought tolerant and susceptible accessions may play an important role in the drought tolerance of perennial ryegrass. They can be used as candidate genes in examining nucleotide polymorphisms and conducting the association analysis of genes with drought tolerance.

  20. [Response of leaf anatomical characteristics of Cyclobalanopsis gilva seedlings to drought stress].

    Science.gov (United States)

    Wu, Li-jun; Li, Zhi-hui; Yang, Mo-hua; Wang, Pei-lan

    2015-12-01

    In this study, the leaf anatomical characteristics and transpiration rate of one-year-old seedlings from three study areas including Qingyuan of Zhejiang Province, Dongkou and Jingzhou of Hunan Province were investigated using a pot planting experiment in which relative soil water content was kept as 75%-80% (control), 55%-60% (mild drought stress), 45%-50% (moderate drought stress), 30%-35% (severe drought stress), respectively. The results showed that drought stress significantly reduced the total thickness of the seedling leaves, the thickness of their upper and lower epidermis and the thickness of palisade tissue. The ratio of the palisade tissue to spongy tissue, stomatal length and width also decreased significantly, while the stomatal density increased significantly as the drought stress became more intense. The treatments of drought stress had no significant effect on the thickness of the main veins of the leaves although their xylem thickness varied depending on the seedlings from the different study sites. The change of leaf structure caused the change of physiological function. As drought stress was intensified, the transpiration rate of C. gilva seedlings decreased significantly. The ratio of the palisade tissue to spongy tissue, the thickness of the lower epidermis and stomatal density of the seedlings from Dongkou of Hunan Province were significantly greater, while the transpiration rate was significantly lower than those from other two study sites for all the drought stress treatments, implying that the C. gilva seedlings from Dongkou of Hunan Province had a stronger drought-resistance ability.

  1. Interannual to decadal summer drought variability over Europe and its relationship to global sea surface temperature

    Energy Technology Data Exchange (ETDEWEB)

    Ionita, M.; Lohmann, G. [Alfred Wegener Institute for Polar and Marine Research, Bremerhaven (Germany); University of Bremen, MARUM, Bremen (Germany); Rimbu, N. [Alfred Wegener Institute for Polar and Marine Research, Bremerhaven (Germany); Climed Norad, Bucharest (Romania); Bucharest University, Faculty of Physics, Bucharest (Romania); Chelcea, S. [National Institute of Hydrology and Water Management, Bucharest (Romania); Dima, M. [Alfred Wegener Institute for Polar and Marine Research, Bremerhaven (Germany); Bucharest University, Faculty of Physics, Bucharest (Romania)

    2012-01-15

    Interannual to decadal variability of European summer drought and its relationship with global sea surface temperature (SST) is investigated using the newly developed self calibrated Palmer drought severity index (scPDSI) and global sea surface temperature (SST) field for the period 1901-2002. A European drought severity index defined as the average of scPDSI over entire Europe shows quasiperiodic variations in the 2.5-5 year band as well as at 12-13 years suggesting a possible potential predictability of averaged drought conditions over Europe. A Canonical Correlation Analysis between summer scPDSI anomalies over Europe and global SST anomalies reveals the existence of three modes of coupled summer drought scPDSI patterns and winter global SST anomalies. The first scPDSI-SST coupled mode represents the long-term trends in the data which manifest in SST as warming over all oceans. The associated long-term trend in scPDSI suggests increasing drought conditions over the central part of Europe. The second mode is related to the inter-annual ENSO and decadal PDO influence on the European climate and the third one captures mainly the drought pattern associated to Atlantic Multidecadal Oscillation. The lag relationships between winter SST and summer drought conditions established in this study can provide a valuable skill for the prediction of drought conditions over Europe on interannual to decadal time scales. (orig.)

  2. The use of satellite data for agriculture drought risk quantification in Ukraine

    Directory of Open Access Journals (Sweden)

    Sergii Skakun

    2016-05-01

    Full Text Available This paper focuses on drought risk assessment using satellite data. Methods of the extreme value theory (EVT are applied for a time series of vegetation health index (VHI derived from the National Oceanic and Atmospheric Administration satellites in order to provide drought hazard mapping. A Poisson-GP (generalized Pareto model is applied for modelling VHI extreme values. The model allows estimation and mapping of return periods of different categories of droughts. An approach to economical risk assessment due to droughts is presented that relies on the following components: damage function assessment, crop yield assessment, and crop area estimation. The advantage of the proposed approach is that it allows quantification of drought hazard through the drought return period, damages, and ultimately drought risk using satellite data. The derived drought hazard map is integrated with high-resolution crop map to provide final estimates of risk. The proposed approach is implemented for quantitative assessment of drought risk for the Kyiv region in Ukraine. The derived map shows that risk is distributed non-uniformly over the region, thus allowing identification of areas with higher risk. Such a map would be of great benefit to both local authorities to take directed actions to reduce the risk and insurance companies operating in agriculture sector.

  3. SPI Based Meteorological Drought Assessment over a Humid Basin: Effects of Processing Schemes

    Directory of Open Access Journals (Sweden)

    Han Zhou

    2016-08-01

    Full Text Available Meteorological drought monitoring is important for drought early warning and disaster prevention. Regional meteorological drought can be evaluated and analyzed with standardized precipitation index (SPI. Two main processing schemes are frequently adopted: (1 mean of all SPI calculated from precipitation at individual stations (SPI-mean; and (2 SPI calculated from all-station averaged precipitation (precipitation-mean. It yet remains unclear if two processing schemes could make difference in drought assessment, which is of significance to reliable drought monitoring. Taking the Poyang Lake Basin with monthly precipitation recorded by 13 national stations for 1957–2014, this study examined two processing schemes. The precipitation mean and SPI mean were respectively calculated with the Thiessen Polygon weighting approach. Our results showed that the two SPI series individually constructed from two schemes had similar features and monitoring trends of regional meteorological droughts. Both SPI series had a significantly positive correlation (p < 0.005 with the number of precipitation stations. The precipitation-mean scheme reduced the extent of precipitation extremes and made the precipitation data more clustered in some certain, it made less precipitation deviate from the precipitation-mean series farther when less precipitation occurred universally, which would probably change the drought levels. Alternatively, the SPI-mean scheme accurately highlighted the extremes especially for those with wide spatial distribution over the region. Therefore, for regional meteorological drought monitoring, the SPI-mean scheme is recommended for its more suitable assessment of historical droughts.

  4. Multiple QTLs Linked to Agro-Morphological and Physiological Traits Related to Drought Tolerance in Potato.

    Science.gov (United States)

    Khan, M Awais; Saravia, David; Munive, Susan; Lozano, Flavio; Farfan, Evelyn; Eyzaguirre, Raul; Bonierbale, Merideth

    Dissection of the genetic architecture of adaptation and abiotic stress-related traits is highly desirable for developing drought-tolerant potatoes and enhancing the resilience of existing cultivars, particularly as agricultural production in rain-fed areas may be reduced by up to 50 % by 2020. The "DMDD" potato progeny was developed at International Potato Center (CIP) by crossing the sequenced double monoploid line DM and a diploid cultivar of the Solanum tuberosum diploid Andigenum Goniocalyx group. Recently, a high-density integrated genetic map based on single nucleotide polymorphism (SNP), diversity array technology (DArT), simple sequence repeats (SSRs), and amplified fragment length polymorphism (AFLP) markers was also made available for this population. Two trials were conducted, in greenhouse and field, for drought tolerance with two treatments each, well-watered and terminal drought, in which watering was suspended 60 days after planting. The DMDD population was evaluated for agro-morphological and physiological traits before and after initiation of stress, at multiple time points. Two dense parental genetic maps were constructed using published genotypic data, and quantitative trait locus (QTL) analysis identified 45 genomic regions associated with nine traits in well-watered and terminal drought treatments and 26 potentially associated with drought stress. In this study, the strong influence of environmental factors besides water shortage on the expression of traits and QTLs reflects the multigenic control of traits related to drought tolerance. This is the first study to our knowledge in potato identifying QTLs for drought-related traits in field and greenhouse trials, giving new insights into genetic architecture of drought-related traits. Many of the QTLs identified have the potential to be used in potato breeding programs for enhanced drought tolerance.

  5. Sustained impact of drought on wet shrublands mediated by soil physical changes

    Science.gov (United States)

    Dominguez, Maria T.; Smith, Andrew; Robinson, David; van Baarsel, Susie; Mills, Robert; Marshall, Miles; Koller, Eva; Lebron, Inma; Hall, Jane; Emmett, Bridget

    2015-04-01

    Projected warming, and increasingly frequent extreme events such as drought, may substantially enhance soil organic matter decomposition in wet organic soils, contributing to the positive feedback between the terrestrial carbon cycle and climate change. Evidence suggests that, as wet organic soils contain large organic C stocks, acclimation to warming might occur more slowly in comparison to mineral soils. The long-term response of wet organic soils to drought remains however uncertain. Ecosystems with organo-mineral soils might be more vulnerable to drought events than peatlands, because of a limited soil moisture pool being available to buffer drying events. We investigated the long-term (14 years) impact of warming and repeated summer droughts on soil respiration from podzolic (organo-mineral) soils in a wet shrubland, using a whole-ecosystem climate-change experiment in North Wales, UK. The experimental drought aimed to emulate the UK summer drought of 1995, considered to be the most recent significant drought year prior to treatment initiation. The impact of drought (average respiration stimulation of 22 % for all seasons and years) was enhanced over the years, which was linked to major changes in soil structure that led to a 54 % reduction in water holding capacity. Bryophyte abundance was found to buffer soil moisture losses. After a bryophyte expansion in 2005 the impact of warming on soil efflux was attenuated; this suggests that bryophytes might have a key role in the resilience these soils to warming despite their relatively small contribution to total aboveground biomass. Plant productivity was very resilient to warming or drought, indicating that the increases in soil respiration have not been balanced by increases in C inputs to soil. The results indicate the potentially critical role that changes in sub-dominant vegetation and in soil physical properties may have in determining climate change impacts on soil C dynamics.

  6. Projecting future climate change effects on the extreme hydrological drought events in the Weihe River basin, China

    Science.gov (United States)

    Yuan, F.; San, Y. Y.; Li, Y.; Ma, M.; Ren, L.; Zhao, C.; Liu, Y.; Yang, X.; Jiang, S.; Shen, H.

    2015-06-01

    In this study, a framework to project the potential future climate change impacts on extreme hydrological drought events in the Weihe River basin in North China is presented. This framework includes a large-scale hydrological model driven by climate outputs from a regional climate model for historical streamflow simulations and future streamflow projections, and models for univariate drought assessment and copula-based bivariate drought analysis. It is projected by the univariate drought analysis that future climate change would lead to increased frequencies of extreme hydrological drought events with higher severity. The bivariate drought assessment using copula shows that future droughts in the same return periods as historical droughts would be potentially longer and more severe, in terms of drought duration and severity. This trend would deteriorate the hydrological drought situation in the Weihe River basin. In addition, the uncertainties associated with climate models, hydrological models, and univariate and bivariate drought analysis should be quantified in the future research to improve the reliability of this study.

  7. effect of temporary drought at different growth stages on snap bean ...

    African Journals Online (AJOL)

    ACSS

    However, drought may occur at any stage of growth of snap bean. The objective ... flowering and pod formation, against a control with no drought stress. .... determined and the average yield was calculated .... A two-way ANOVA was ..... concentrations in pods showed similar patterns .... various milk samples available in.

  8. The impacts of increasing drought on forest dynamics, structure, and biodiversity in the United States

    Science.gov (United States)

    James S. Clark; Louis Iverson; Christopher W. Woodall; Craig D. Allen; David M. Bell; Don C. Bragg; Anthony W. D' Amato; Frank W. Davis; Michelle H. Hersh; Ines Ibanez; Stephen T. Jackson; Stephen Matthews; Neil Pederson; Matthew Peters; Mark W. Schwartz; Kristen M. Waring; Niklaus E. Zimmermann

    2016-01-01

    We synthesize insights from current understanding of drought impacts at stand-to-biogeographic scales, including management options, and we identify challenges to be addressed with new research. Large stand-level shifts underway in western forests already are showing the importance of interactions involving drought, insects, and fire. Diebacks, changes in composition...

  9. Projected climatic changes on drought conditions over Spain

    Science.gov (United States)

    García-Valdecasas Ojeda, Matilde; Quishpe-Vásquez, César; Raquel Gámiz-Fortis, Sonia; Castro-Díez, Yolanda; Jesús Esteban-Parra, María

    2017-04-01

    In a context of global warming, the evapotranspiration processes will have a strong influence on drought severity. For this reason, the Standardized Precipitation Evapotranspiration Index (SPEI) was computed at different timescales in order to explore the projected drought changes for the main watersheds in Spain. For that, the Weather Research and Forecasting (WRF) model has been used in order to obtain current (1980-2010) and future (2021-2050 and 2071-2100) climate output fields. WRF model was used over a domain that spans the Iberian Peninsula with a spatial resolution of 0.088°, and nested in the coarser 0.44° EURO-CORDEX domain, and driving by the global bias-corrected climate model output data from version 1 of NCAR's Community Earth System Model (CESM1), using two different Representative Concentration Pathway (RCP) scenarios: RCP 4.5 and RCP 8.5. Besides, to examine the behavior of this drought index, a comparison with the Standardized Precipitation Index (SPI), which does not consider the evapotranspiration effects, was also performed. Additionally the relationship between the SPEI index and the soil moisture has also been analyzed. The results of this study suggest an increase in the severity and duration of drought, being larger when the SPEI index is used to define drought events. This fact confirms the relevance of taking into account the evapotranspiration processes to detect future drought events. The results also show a noticeable relationship between the SPEI and the simulated soil moisture content, which is more significant at higher timescales. Keywords: Drought, SPEI, SPI, Climatic change, Projections, WRF. Acknowledgements: This work has been financed by the projects P11-RNM-7941 (Junta de Andalucía-Spain) and CGL2013-48539-R (MINECO-Spain, FEDER).

  10. Eastward propagating MJO during boreal summer and Indian monsoon droughts

    Energy Technology Data Exchange (ETDEWEB)

    Joseph, Susmitha; Sahai, A.K.; Goswami, B.N. [Indian Institute of Tropical Meteorology, Climate and Global Modeling Division, Pune (India)

    2009-06-15

    Improved understanding of underlying mechanism responsible for Indian summer monsoon (ISM) droughts is important due to their profound socio-economic impact over the region. While some droughts are associated with 'external forcing' such as the El-Nino and Southern Oscillation (ENSO), many ISM droughts are not related to any known 'external forcing'. Here, we unravel a fundamental dynamic process responsible for droughts arising not only from external forcing but also those associated with internal dynamics. We show that most ISM droughts are associated with at least one very long break (VLB; breaks with duration of more than 10 days) and that the processes responsible for VLBs may also be the mechanism responsible for ISM droughts. Our analysis also reveals that all extended monsoon breaks (whether co-occurred with El-Nino or not) are associated with an eastward propagating Madden-Julian Oscillation (MJO) in the equatorial Indian Ocean and western Pacific extending to the dateline and westward propagating Rossby waves between 10 and 25 N. The divergent Rossby wave associated with the dry phase of equatorial convection propagates westward towards Indian land, couple with the northward propagating dry phase and leads to the sustenance of breaks. Thus, the propensity of eastward propagating MJO during boreal summer is largely the cause of monsoon droughts. While short breaks are not accompanied by westerly wind events (WWE) over equatorial western Pacific favorable for initiating air-sea interaction, all VLBs are accompanied by sustained WWE. The WWEs associated with all VLB during 1975-2005 initiate air-sea interaction on intraseasonal time scale, extend the warm pool eastward allowing the convectively coupled MJO to propagate further eastward and thereby sustaining the divergent circulation over India and the monsoon break. The ocean-atmosphere coupling on interannual time scale (such as El-Nino) can also produce VLB, but not necessary. (orig.)

  11. Eastward propagating MJO during boreal summer and Indian monsoon droughts

    Science.gov (United States)

    Joseph, Susmitha; Sahai, A. K.; Goswami, B. N.

    2009-06-01

    Improved understanding of underlying mechanism responsible for Indian summer monsoon (ISM) droughts is important due to their profound socio-economic impact over the region. While some droughts are associated with ‘external forcing’ such as the El-Niño and Southern Oscillation (ENSO), many ISM droughts are not related to any known ‘external forcing’. Here, we unravel a fundamental dynamic process responsible for droughts arising not only from external forcing but also those associated with internal dynamics. We show that most ISM droughts are associated with at least one very long break (VLB; breaks with duration of more than 10 days) and that the processes responsible for VLBs may also be the mechanism responsible for ISM droughts. Our analysis also reveals that all extended monsoon breaks (whether co-occurred with El-Niño or not) are associated with an eastward propagating Madden-Julian Oscillation (MJO) in the equatorial Indian Ocean and western Pacific extending to the dateline and westward propagating Rossby waves between 10° and 25°N. The divergent Rossby wave associated with the dry phase of equatorial convection propagates westward towards Indian land, couple with the northward propagating dry phase and leads to the sustenance of breaks. Thus, the propensity of eastward propagating MJO during boreal summer is largely the cause of monsoon droughts. While short breaks are not accompanied by westerly wind events (WWE) over equatorial western Pacific favorable for initiating air-sea interaction, all VLBs are accompanied by sustained WWE. The WWEs associated with all VLB during 1975-2005 initiate air-sea interaction on intraseasonal time scale, extend the warm pool eastward allowing the convectively coupled MJO to propagate further eastward and thereby sustaining the divergent circulation over India and the monsoon break. The ocean-atmosphere coupling on interannual time scale (such as El-Niño) can also produce VLB, but not necessary.

  12. Does drought alter hydrological functions in forest soils?

    Science.gov (United States)

    Gimbel, Katharina F.; Puhlmann, Heike; Weiler, Markus

    2016-04-01

    Climate change is expected to impact the water cycle and severely affect precipitation patterns across central Europe and in other parts of the world, leading to more frequent and severe droughts. Usually when projecting drought impacts on hydrological systems, it is assumed that system properties, like soil properties, remain stable and will not be affected by drought events. To study if this assumption is appropriate, we address the effects of drought on the infiltration behavior of forest soils using dye tracer experiments on six sites in three regions across Germany, which were forced into drought conditions. The sites cover clayey-, loamy- and sandy-textured soils. In each region, we compared a deciduous and a coniferous forest stand to address differences between the main tree species. The results of the dye tracer experiments show clear evidence for changes in infiltration behavior at the sites. The infiltration changed at the clayey plots from regular and homogeneous flow to fast preferential flow. Similar behavior was observed at the loamy plots, where large areas in the upper layers remained dry, displaying signs of strong water repellency. This was confirmed by water drop penetration time (WDPT) tests, which revealed, in all except one plot, moderate to severe water repellency. Water repellency was also accountable for the change of regular infiltration to fingered flow in the sandy soils. The results of this study suggest that the drought history or, more generally, the climatic conditions of a soil in the past are more important than the actual antecedent soil moisture status regarding hydrophobicity and infiltration behavior; furthermore, drought effects on infiltration need to be considered in hydrological models to obtain realistic predictions concerning water quality and quantity in runoff and groundwater recharge.

  13. On the propagation of drought : how climate and catchment characteristics influence hydrological drought development and recovery

    NARCIS (Netherlands)

    Loon, van A.F.

    2013-01-01

    Drought is a severe natural disaster resulting in high economic loss and huge ecological and societal impacts. In this thesis drought is defined as a period of below-normal water availability in precipitation (meteorological drought), soil moisture (soil moisture drought), or groundwater and

  14. On the propagation of drought : how climate and catchment characteristics influence hydrological drought development and recovery

    NARCIS (Netherlands)

    Loon, van A.F.

    2013-01-01

    Drought is a severe natural disaster resulting in high economic loss and huge ecological and societal impacts. In this thesis drought is defined as a period of below-normal water availability in precipitation (meteorological drought), soil moisture (soil moisture drought), or groundwater and dischar

  15. On the propagation of drought : how climate and catchment characteristics influence hydrological drought development and recovery

    NARCIS (Netherlands)

    Loon, van A.F.

    2013-01-01

    Drought is a severe natural disaster resulting in high economic loss and huge ecological and societal impacts. In this thesis drought is defined as a period of below-normal water availability in precipitation (meteorological drought), soil moisture (soil moisture drought), or groundwater and dischar

  16. Drought May Beckon Bigger West Nile Outbreaks

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_163495.html Drought May Beckon Bigger West Nile Outbreaks Dry environment ... found that epidemics were larger during years of drought. There were also bigger outbreaks in areas that ...

  17. Forest biogeochemistry in response to drought.

    Science.gov (United States)

    Schlesinger, William H; Dietze, Michael C; Jackson, Robert B; Phillips, Richard P; Rhoades, Charles C; Rustad, Lindsey E; Vose, James M

    2016-07-01

    Trees alter their use and allocation of nutrients in response to drought, and changes in soil nutrient cycling and trace gas flux (N2 O and CH4 ) are observed when experimental drought is imposed on forests. In extreme droughts, trees are increasingly susceptible to attack by pests and pathogens, which can lead to major changes in nutrient flux to the soil. Extreme droughts often lead to more common and more intense forest fires, causing dramatic changes in the nutrient storage and loss from forest ecosystems. Changes in the future manifestation of drought will affect carbon uptake and storage in forests, leading to feedbacks to the Earth's climate system. We must improve the recognition of drought in nature, our ability to manage our forests in the face of drought, and the parameterization of drought in earth system models for improved predictions of carbon uptake and storage in the world's forests.

  18. Drought Analysis of Haihe Basin in North China based on the Community Land Model, 1960-2010

    Science.gov (United States)

    Qin, Y.; Yang, D.; Lei, H.

    2014-12-01

    Drought severity not only depends on weather anomaly, but is also related to terrestrial hydrological condition to a large extent. In this study, we analyzed droughts using indices based on precipitation and soil moisture during the period of 1960-2010 in Haihe basin, which is a typical drought-prone region in North China. The Soil Moisture Drought Severity (SMDS) and Standardized Precipitation Index (SPI) are used to evaluate drought severity. SMDS is calculated based on the monthly soil moisture of upper 50cm from the simulation by Community Land Model (CLM 4.0) and SPI is calculated based on gridded precipitation at 0.05° resolution (5 km × 5 km approximately), which is spatially interpolated from observations. During the last 51 years, 36 severe drought events (affecting areas greater than 20,000 km2 and durations longer than 3 months) have been identified based on SMDS, and 41 drought events identified based on SPI. Results derived from SMDS indicate that there is a significant increasing trend in the drought affected area, and that the drought event occurred in 1999 has the largest affected area. Compared with the drought events derived from SMDS, the events derived from SPI have shorter durations but larger affected areas on average. Although the mean NDVI of the whole basin has been increasing since the 1980s, the two declining periods of 1992-1994 and 1999-2003 show fairly good agreement with the drought events identified in the same periods. Comparison between SMDS and SPI shows the superiority of SMDS for drought assessment in the perspective of terrestrial ecosystem. Keywords: Drought analysis; Standardized Precipitation Index (SPI); Soil Moisture Drought Severity (SMDS); Community Land Model; Haihe basin

  19. Droughts in the US: Modeling and Forecasting for Agriculture-Water Management and Adaptation

    Science.gov (United States)

    Perveen, S.; Devineni, N.; Lall, U.

    2012-12-01

    been accessed for the agricultural data at the county level. Preliminary analyses show that large parts of Midwest and Southern parts of Florida and California are prone to multiyear droughts. This can primarily be attributed to high agricultural and/or urban water demands coupled with high interannual variability in supply. We propose to develop season-ahead and monthly updated forecasts of the drought index for informing the drought management plans. Given the already customized (sector specific) nature of the proposed drought index and its ability to represent the variability in both supply and demand, the early warning or forecasting of the index would not only complement the drought early warning systems in place by the national integrated drought information system (NIDIS) but also help in prescribing the ameliorative measures for adaptation.

  20. The day-to-day monitoring of the 2011 severe drought in China

    Science.gov (United States)

    Lu, Er; Cai, Wenyue; Jiang, Zhihong; Zhang, Qiang; Zhang, Cunjie; Higgins, R. Wayne; Halpert, Michael S.

    2014-07-01

    Dry/wet condition has a large interannual variability. Decision-makers need to know the onset, duration, and intensity of drought, and require droughts be monitored at a daily to weekly scale. However, previous tools cannot monitor drought well at this short timescale. The Palmer Drought Severity Index has been found dissatisfactory in monitoring because of its complexity and numerous limitations. The Standardized Precipitation Index (SPI) always asks for a timescale, and precipitation is averaged over the period of the scale. Because of this, the SPI cannot be used for short scales, e.g., several days, and what it tells is the overall drought situation of the period. The weighted average of precipitation (WAP) developed by Lu (Geophys Res Lett 36:L12707, 2009) overcomes the deficiency of the SPI; it does not require a timescale, and can provide the drought (and flood) extent of each day. Therefore, the WAP can monitor drought at scales from daily to weekly, monthly, and any longer scale, and is really "flexible and versatile for all timescales". In this study, the standardized WAP (SWAP) is used to monitor the 2011 drought over China. Drought swept the country during the year from north to south and from east to west. In spring, a once-in-a-fifty-year drought occurred over the Yangtze River basin and the southern region, causing serious shortage of drinking water for people and livestock, as well as tremendous losses in agriculture and the shipping industry. Results show that the SWAP, with its monthly mean plots, can well reproduce the seasonal shift of the 2011 drought across the country. The animation of daily plots demonstrates that the SWAP would have been able to monitor the day-to-day variation of the spring drought around the Yangtze River basin. It can provide the details of the drought, such as when the drought emerged over the region, how long it maintained there (though drought area may move back and forth with extension and contraction of the area

  1. Mining of simple sequence repeats in the Genome of Gentianaceae

    Directory of Open Access Journals (Sweden)

    R Sathishkumar

    2011-01-01

    Full Text Available Simple sequence repeats (SSRs or short tandem repeats are short repeat motifs that show high level of length polymorphism due to insertion or deletion mutations of one or more repeat types. Here, we present the detection and abundance of microsatellites or SSRs in nucleotide sequences of Gentianaceae family. A total of 545 SSRs were mined in 4698 nucleotide sequences downloaded from the National Center for Biotechnology Information (NCBI. Among the SSR sequences, the frequency of repeat type was about 429 -mono repeats, 99 -di repeats, 15 -tri repeats, and 2 --hexa repeats. Mononucleotide repeats were found to be abundant repeat types, about 78%, followed by dinucleotide repeats (18.16% among the SSR sequences. An attempt was made to design primer pairs for 545 identified SSRs but these were found only for 169 sequences.

  2. How tree species-specific drought responses influence the carbon-water interaction in temperate forests

    Science.gov (United States)

    Wolf, Annett; Leuzinger, Sebastian; Bugmann, Harald

    2010-05-01

    Climate-change-induced differences in soil moisture conditions will influence the carbon uptake of tree species and hence the carbon budget of ecosystems. Experimental data showed that in a mature deciduous forest tree transpiration during a prolonged drought was reduced in a species-specific manner (Leuzinger et al. 2005). We implemented such a differential drought responses using the ecosystem model LPJ-GUESS. We simulated forest ecosystems in central Europe, using mixed forests and single species stands. The model showed that one result of the species specific drought response are differences in tree species diversity in the long run. At the intra-annual scale, we showed that a reduction in ecosystem evapotranspiration at an early stage during the drought period resulted in lower water stress later on in the drought. A consequence was that drought sensitive tree species could maintain a positive carbon balance during longer drought periods. As drought periods are likely to become more frequent and/or longer in many parts of the world, projections of ecosystem responses will be sensitive to the processes investigated here, and therefore ecosystem models should be upgraded to take them into account. Leuzinger et al. (2005) Tree physiology 25: 641-650.

  3. Morphological characteristic of purple long yard bean cultivars and their tolerance to drought stress

    Directory of Open Access Journals (Sweden)

    M W Lestari

    2015-01-01

    Full Text Available The cultivation of purple long yard bean which tolerance to drought stress and have high productivity can improve farming in arid area. The purpose of this study was to evaluate the mechanism of the tolerance purple long yard beans to drought stress based on morphologic characters, to get the hypothesis method of tolerance and to obtain tolerance cultivars to the drought stress. Eight cultivars of purple long yard beans, i.e. UBPHU1-41, UBPHU1-130, UBPU3-153, UBPU1-202, UBPU2-222, UBPU1-365, Brawijaya 4 and Bagong 2, were tested in two environmental conditions, 100% field capacity and 50% field capacity. The results showed that drought stress in purple long yard bean affected all morphological characters observed, except for root length and flowering time. Estimation of tolerance to drought stress using the Principles Component Analysis (PCA showed that the shoot fresh weight could be an indicator of purple pod bean tolerance to drought stress. However, the test using Stress Susceptibility Index (SSI was not able to classify the purple long yard bean tolerance to drought stress. The results of analysis using PCA followed by discriminant analysis and clustering dendrogram showed that the UBPU1-41, UBPU1-130, UBPU2-222, UBPU1-365, UB4 and Bagong 2 cultivars were medium cultivars that are tolerant to drought stress. Therefore, they can be planted in semiarid regions.

  4. Using multifractal and wavelet analyses to determine drought characteristics: a case study of Jilin province, China

    Science.gov (United States)

    Zhang, Qian; Lu, Wenxi; Chen, Sheming; Liang, Xiujuan

    2016-08-01

    Drought is a recurrent disaster that occurs in virtually all climatic zones of the world. However, drought characteristics vary substantially among different climatic regions. In this study, multifractal and wavelet analyses are used to characterize drought based on monthly precipitation. The rainfall data of 28 precipitation stations from 1958 to 2011 in Jilin province were collected to calculate the standardized precipitation index (SPI), and the negative monthly SPI time-series is used in a multiscaling approach to determine drought characteristics in Jilin province. Simple scaling and multiscaling analyses show significant variations in monthly droughts in the region. Morlet wavelet analysis also shows that significant cycles and multiple time-scales of drought exist in all stations. Cross wavelet analysis shows that drought occurrence in the region is mainly influenced by different climatic factor scales. However, different factors have different degrees of influence at different regions. The enduring influence of medium and long-term climatic patterns (such as El Niño events) may lead to the simple scaling behavior of drought for some regions.

  5. Identification of the influencing factors on groundwater drought and depletion in north-western Bangladesh

    Science.gov (United States)

    Mustafa, Syed Md. Touhidul; Abdollahi, Khodayar; Verbeiren, Boud; Huysmans, Marijke

    2017-08-01

    Groundwater drought is a specific type of hydrological drought that concerns groundwater bodies. It may have a significant adverse effect on the socio-economic, agricultural, and environmental conditions. Investigating the effect of different climatic and anthropogenic factors on groundwater drought provides essential information for sustainable planning and management of (ground) water resources. The aim of this study is to identify the influencing factors on groundwater drought in north-western Bangladesh, to understand the forcing mechanisms. A multi-step methodology is proposed to achieve this objective. The standardised precipitation index (SPI) and reconnaissance drought index (RDI) have been used to quantify the aggregated deficit between precipitation and the evaporative demand of the atmosphere, i.e. meteorological drought. The influence of land-cover patterns on the groundwater drought has been identified by calculating spatially distributed groundwater recharge as a function of land cover. Groundwater drought is defined by a threshold method. The results show that the evapotranspiration and rainfall deficits are determining meteorological drought, which shows a direct relation with groundwater recharge deficits. Land-cover change has a small effect on groundwater recharge but does not seem to be the main cause of groundwater-level decline (depletion) in the study area. The groundwater depth and groundwater-level deficit (drought) is continuously increasing with little correlation to meteorological drought or recharge anomalies. Overexploitation of groundwater for irrigation seems to be the main cause of groundwater-level decline in the study area. Efficient irrigation management is essential to reduce the growing pressure on groundwater resources and ensure sustainable water management.

  6. A generic method for hydrological drought identification across different climate regions

    Directory of Open Access Journals (Sweden)

    M. H. J. van Huijgevoort

    2012-08-01

    Full Text Available The identification of hydrological drought at global scale has received considerable attention during the last decade. However, climate-induced variation in runoff across the world makes such analyses rather complicated. This especially holds for the drier regions of the world (both cold and warm, where, for a considerable period of time, zero runoff can be observed. In the current paper, we present a method that enables to identify drought at global scale across climate regimes in a consistent manner. The method combines the characteristics of the classical variable threshold level method that is best applicable in regions with non-zero runoff most of the time, and the consecutive dry days (period method that is better suited for areas where zero runoff occurs. The newly presented method allows a drought in periods with runoff to continue in the following period without runoff. The method is demonstrated by identifying droughts from discharge observations of four rivers situated within different climate regimes, as well as from simulated runoff data at global scale obtained from an ensemble of five different land surface models. The identified drought events obtained by the new approach are compared to those resulting from application of the variable threshold level method or the consecutive dry period method separately. Results show that, in general, for drier regions, the threshold level method overestimates drought duration, because zero runoff periods are included in a drought, according to the definition used within this method. The consecutive dry period method underestimates drought occurrence, since it cannot identify droughts for periods with runoff. The developed method especially shows its relevance in transitional areas, because, in wetter regions, results are identical to the classical threshold level method. By combining both methods, the new method is able to identify single drought events that occur during positive and zero

  7. A generic method for hydrological drought identification across different climate regions

    Directory of Open Access Journals (Sweden)

    M. H. J. van Huijgevoort

    2012-02-01

    Full Text Available The identification of hydrological drought at global scale has received considerable attention during the last decade. However, climate-induced variation in runoff across the world makes such analyses rather complicated. This especially holds for the drier regions of the world (both cold and warm, where for a considerable period of time, zero runoff can be observed. In the current paper, we present a method that enables to identify drought at global scale across climate regimes in a consistent manner. The method combines the characteristics of the classical variable threshold level method that is best applicable in regions with non zero runoff most of the time, and the consecutive dry days (period method that is better suited for areas where zero runoff occurs. The newly presented method allows a drought in periods with runoff to continue in the following period without runoff. The method was demonstrated by identifying droughts from discharge observations of four rivers situated within different climate regimes, as well as from simulated runoff data at global scale obtained from an ensemble of five different land surface models. The identified drought events obtained by the new approach were compared to those resulting from application of the variable threshold level method or the consecutive dry period method separately. Results show that, in general, for drier regions, the threshold level method overestimates drought duration, because zero runoff periods were included in a drought, according to the definition used within this method. The consecutive dry period method underestimates drought occurrence, since it cannot identify droughts for periods with runoff. The developed method especially shows its relevance in transitional areas, because in wetter regions, results were identical to the classical threshold level method. By combining both methods, the new method is able to identify single drought events that occur during positive and zero

  8. Changes and Relationships of Climatic and Hydrological Droughts in the Jialing River Basin, China.

    Directory of Open Access Journals (Sweden)

    Xiaofan Zeng

    Full Text Available The comprehensive assessment of climatic and hydrological droughts in terms of their temporal and spatial evolutions is very important for water resources management and social development in the basin scale. To study the spatial and temporal changes of climatic and hydrological droughts and the relationships between them, the SPEI and SDI are adopted to assess the changes and the correlations of climatic and hydrological droughts by selecting the Jialing River basin, China as the research area. The SPEI and SDI at different time scales are assessed both at the entire Jialing River basin and at the regional levels of the three sub basins. The results show that the SPEI and SDI are very suitable for assessing the changes and relationships of climatic and hydrological droughts in large basins. Based on the assessment, for the Jialing River basin, climatic and hydrological droughts have the increasing tendency during recent several decades, and the increasing trend of climatic droughts is significant or extremely significant in the western and northern basin, while hydrological drought has a less significant increasing trend. Additionally, climatic and hydrological droughts tend to increase in the next few years. The results also show that on short time scales, climatic droughts have one or two months lag impact on hydrological droughts in the north-west area of the basin, and have one month lag impact in south-east area of the basin. The assessment of climatic and hydrological droughts based on the SPEI and SDI could be very useful for water resources management and climate change adaptation at large basin scale.

  9. Changes and Relationships of Climatic and Hydrological Droughts in the Jialing River Basin, China.

    Science.gov (United States)

    Zeng, Xiaofan; Zhao, Na; Sun, Huaiwei; Ye, Lei; Zhai, Jianqing

    2015-01-01

    The comprehensive assessment of climatic and hydrological droughts in terms of their temporal and spatial evolutions is very important for water resources management and social development in the basin scale. To study the spatial and temporal changes of climatic and hydrological droughts and the relationships between them, the SPEI and SDI are adopted to assess the changes and the correlations of climatic and hydrological droughts by selecting the Jialing River basin, China as the research area. The SPEI and SDI at different time scales are assessed both at the entire Jialing River basin and at the regional levels of the three sub basins. The results show that the SPEI and SDI are very suitable for assessing the changes and relationships of climatic and hydrological droughts in large basins. Based on the assessment, for the Jialing River basin, climatic and hydrological droughts have the increasing tendency during recent several decades, and the increasing trend of climatic droughts is significant or extremely significant in the western and northern basin, while hydrological drought has a less significant increasing trend. Additionally, climatic and hydrological droughts tend to increase in the next few years. The results also show that on short time scales, climatic droughts have one or two months lag impact on hydrological droughts in the north-west area of the basin, and have one month lag impact in south-east area of the basin. The assessment of climatic and hydrological droughts based on the SPEI and SDI could be very useful for water resources management and climate change adaptation at large basin scale.

  10. Multi-year strongest California drought from 500 m SNPP/VIIRS

    Science.gov (United States)

    Guo, W.; Kogan, F.

    2016-12-01

    Starting in 2006, the western United States was affected by a 10-year long mega-drought. Among 17 western states, California was the most severely drought-affected, especially in 2012-2015, when the area of stronger than moderate vegetation stress reached 70%. This drought had considerable impacts on California's environmental, economy and society. Currently, drought in the USA is monitored by the US Drought Monitor (USDM), which estimates drought area and intensity on an area with an effective resolution of around 30-by-30 km. California produces more than 90% of US fruits, vegetables, berries and nuts, which are grown on relatively small areas (200-500 acres, or 0.5 to 2 km²). Since most of these crops are irrigated, it is important to estimate crop conditions on the area comparable to the size of the planted crop. This paper demonstrates how the new 0.5-by-0.5 km Vegetation health (VH) technology (VH-500) developed from the data collected by the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi National Polar-orbiting Partnership (SNPP) satellite launched in 2011, monitors the current mega-drought in California, distinguishing drought-affected area with and without irrigation and estimating drought start/end, intensity, duration and impacts. The VH-500 method and data showed that California's vegetation was under medium-to-exceptional stress, especially in 2013 and 2014. However, in the middle of such intensive stress, in some of the 500-m areas of the Central Valley where principal crops are growing, vegetation experienced favorable conditions because some of these crops were irrigated. The VH-500 drought estimates showed general similarities with the assessed economic drought impacts (crop fallowing, employment loss and crop revenue change) in California.

  11. Germination Characteristics of Marshmallow (Althea officinalis L. as Influenced by Drought and Salinity Stress

    Directory of Open Access Journals (Sweden)

    R Yazdani Biuki

    2012-07-01

    Full Text Available Drought and salinity are two important environmental stresses limiting the crop production. In order to study the influence of drought and salinity stresses on germination characteristics of Marshmallow plant seeds, two separate experiments were conducted based on completely randomized design with four replications in controlled conditions. Drought stress levels were 0, -2, -4, -6 and -8 bar in the first experiment and salinity stress levels were 0, -2, -4, -6, -8 and -10 bar in the second experiment which were accomplished using PEG 6000 and sodium chloride, respectively. The results indicated a decrease in germination rate and percentage, as well as in lengths and fresh and dry weights of both plumules and radicles, as the osmotic potential was reduced in both experiments. Marshmallow seeds showed an overall higher tolerance against salinity stress compared to drought stress, with germination occurring at as low osmotic potentials as -10 bars in salinity treatments, while only until -8 bar drought stress. In osmotic potentials of -2 and -4 bar the decrease in germination percentage was more sever in the salinity stress compared to drought stress; whereas in higher levels of stress (-6 and -8 bar drought stress brought about a higher decrease in germination percentage than did the salinity stress; illustrated by the percentage of germination decrease at -6 bar, i.e. 63% for drought and 80% for salinity treatments. At the treatments of higher potential (-2, -4 and -6 bar the decrease in radicle length was greater in response to salinity than to drought stress, but the length of plumule was more influenced by drought stress and also showed the highest sensitivity to drought, among all measured characteristics.

  12. Identification of the influencing factors on groundwater drought and depletion in north-western Bangladesh

    Science.gov (United States)

    Mustafa, Syed Md. Touhidul; Abdollahi, Khodayar; Verbeiren, Boud; Huysmans, Marijke

    2017-02-01

    Groundwater drought is a specific type of hydrological drought that concerns groundwater bodies. It may have a significant adverse effect on the socio-economic, agricultural, and environmental conditions. Investigating the effect of different climatic and anthropogenic factors on groundwater drought provides essential information for sustainable planning and management of (ground) water resources. The aim of this study is to identify the influencing factors on groundwater drought in north-western Bangladesh, to understand the forcing mechanisms. A multi-step methodology is proposed to achieve this objective. The standardised precipitation index (SPI) and reconnaissance drought index (RDI) have been used to quantify the aggregated deficit between precipitation and the evaporative demand of the atmosphere, i.e. meteorological drought. The influence of land-cover patterns on the groundwater drought has been identified by calculating spatially distributed groundwater recharge as a function of land cover. Groundwater drought is defined by a threshold method. The results show that the evapotranspiration and rainfall deficits are determining meteorological drought, which shows a direct relation with groundwater recharge deficits. Land-cover change has a small effect on groundwater recharge but does not seem to be the main cause of groundwater-level decline (depletion) in the study area. The groundwater depth and groundwater-level deficit (drought) is continuously increasing with little correlation to meteorological drought or recharge anomalies. Overexploitation of groundwater for irrigation seems to be the main cause of groundwater-level decline in the study area. Efficient irrigation management is essential to reduce the growing pressure on groundwater resources and ensure sustainable water management.

  13. Propagation of drought through groundwater systems

    NARCIS (Netherlands)

    Peters, E.

    2003-01-01

    Index words: drought, groundwater, simulation, synthetic data, extreme events

    The transformation of droughts as a result of the propagation through groundwater systems is examined by comparing droughts in time

  14. Diversity of seedling responses to drought

    NARCIS (Netherlands)

    Slot, M.; Poorter, L.

    2007-01-01

    Drought is an important seedling mortality agent in dry and moist tropical forests, and more severe and frequent droughts are predicted in the future. The effect of drought on leaf gas exchange and seedling survival was tested in a dry-down experiment with four tree species from dry and moist forest

  15. Propagation of drought through groundwater systems

    NARCIS (Netherlands)

    Peters, E.

    2003-01-01

    Index words: drought, groundwater, simulation, synthetic data, extreme events

    The transformation of droughts as a result of the propagation through groundwater systems is examined by comparing droughts in time se

  16. Comparison of two hydrological drought indices

    Directory of Open Access Journals (Sweden)

    Abhishek A. Pathak

    2016-09-01

    Full Text Available Drought is a naturally occurring periodical event associated with significant decrease of water availability over a region. Drought, being a complex in nature it is difficult to define, quantify and monitor. Drought is mainly classified into meteorological drought, hydrological drought and agricultural drought. Among these classifications, assessment of hydrological drought has more importance in the water resources management perspective. Objective of this study is to analyse multi-time step hydrological drought by Stream flow Drought Index (SDI and Standardized Runoff Index (SRI. To obtain these indices, 36 years (1972–2007 of daily discharge data, measured in Ghataprabha river basin (a sub basin of Krishna river is considered. Results of both indices indicate moderate drought between 1986–1988 and 2001–2005 continuously. While comparing both indices, there is a good correlation between 9-month SRI and SDI is observed and it increases for 12-month SRI and SDI. This study may help to choose the appropriate drought indices among SRI and SDI for different lengths of drought studies.

  17. Effects of drought on avian community structure

    Science.gov (United States)

    Thomas P. Albright; Anna M. Pidgeon; Chadwick D. Rittenhouse; Murray K. Clayton; Curtis H. Flather; Patrick D. Culbert; Brian D. Wardlow; Volker C. Radeloff

    2010-01-01

    Droughts are expected to become more frequent under global climate change. Avifauna depend on precipitation for hydration, cover, and food. While there are indications that avian communities respond negatively to drought, little is known about the response of birds with differing functional and behavioural traits, what time periods and indicators of drought are most...

  18. European Drought and Water Scarcity Policies

    NARCIS (Netherlands)

    Özerol, Gül; Stein, Ulf; Troeltzsch, Jenny; Landgrebe, Ruta; Szendrenyi, Anna; Vidaurre, Rodrigo; Bressers, Hans; Bressers, Nanny; Larrue, Corinne

    2016-01-01

    Over the last decade, Europe’s drought management and policy has been characterized by a predominantly crisis-oriented approach. However, the widening gap between the impacts of drought episodes and the ability to prepare, manage and mitigate such droughts has motivated the European Union (EU) to ma

  19. Do land surface models need to include differential plant species responses to drought? Examining model predictions across a latitudinal gradient in Europe

    OpenAIRE

    M. G. De Kauwe; S.-X. Zhou; B. E. Medlyn; A. J. Pitman; Y.-P. Wang; R. A. Duursma; I. C. Prentice

    2015-01-01

    Future climate change has the potential to increase drought in many regions of the globe, making it essential that land surface models (LSMs) used in coupled climate models, realistically capture the drought responses of vegetation. Recent data syntheses show that drought sensitivity varies considerably among plants from different climate zones, but state-of-the-art LSMs currently assume the same drought sensitivity for all vegetation. We tested whether variable ...

  20. Variation of drought over northern China during 1950-2000%1950-2000年中国北方干旱气候变化

    Institute of Scientific and Technical Information of China (English)

    王志伟; 翟盘茂; 张洪涛

    2003-01-01

    Based on China's monthly precipitation data of 629 stations during 1950-2000, we calculated Z indices and separated them into seven Dryness and Wemess grades. Further, a drought area index was proposed to study changes in drought severity in northern China. The results revealed that the different severity of droughts all showed expanding trends in northern China's main agricultural area. Moreover, the area coverage of droughts in different seasons and different regions displayed different trends.

  1. EXOPOLYSACCHARIDE PRODUCTION BY DROUGHT TOLERANT BACILLUS SPP. AND EFFECT ON SOIL AGGREGATION UNDER DROUGHT STRESS

    Directory of Open Access Journals (Sweden)

    Sandhya Vardharajula

    2014-08-01

    Full Text Available Exopolysaccharides (EPS of microbial origin with novel functionality, reproducible physico-chemical properties, are important class of polymeric materials. EPS are believed to protect bacterial cells from dessication, produce biofilms, thus enhancing the cells chances of bacterial colonizing special ecological niches. In rhizosphere, EPS are known to be useful to improve the moisture-holding capacity. Three Bacillus spp. strains identified by 16s rDNA sequence analysis as B. amyloliquefaciens strain HYD-B17; B. licheniformis strain HYTAPB18; B. subtilis strain RMPB44 were studied for the ability to tolerate matric stress and produce EPS under different water potentials. EPS production in all the three Bacillus spp strains increased with increasing water stress indicating correlation between drought stress tolerance and EPS production. Among the isolates, strain HYD-17 showed highest production of EPS. The exopolysaccharide composition of the three strains was further analyzed by HPLC. Drought stress influenced the ratio of sugars in EPS and glucose was found as major sugar in strains HYTAPB18 and RMPB44 whereas raffinose was major sugar found in strain HYD-B17. Inoculation of EPS producing Bacillus spp. strains in soil resulted in good soil aggregation under drought stress conditions at different incubation periods. This study shows that exposure to water stress conditions affects the composition and ratios of sugars in EPS produced by Bacillus spp. strains HYD-B17, HYTAPB18 and RMPB44 influencing abiotic stress tolerance of the microorganisms.

  2. Evaluation of Spatio-temporal Drought using Water Resource Quantile Map

    Science.gov (United States)

    Moon, Soojin; Suh, Aesook; Kang, Boosik

    2016-04-01

    Among those various natural disasters, the drought which is contrasted to the flood is not defined in only one case and it is true that the standard to estimate and conclude the drought is in vague with the long-term water insufficiency following the local and time-periodic rainfall disparity. Drought indices is mainly used as an index for evaluating drought. However, it is not an absolute indicator that can evaluate drought. Depending on the characteristics of each index in a variety of conditions such as local and environment, after grasping a better applicability in the use surfaces to suit the purpose of the user, using the appropriate index to be drought evaluation shall. After considering the various characteristics such as regional and environment with each index, the drought index have to use appropriately. Accordingly, there has been a lot of research for drought monitoring. However, objective method that can be evaluated experts as well as the general people on the actual drought situation, is deficient. In this study, it suggested RSQM (Real-time Storage Quantile Map) and RRQM (Real-time Riverflow Quantile Map) in the way to calculating the quantile of the current value corresponding to the usual value of the annual value river water level and storage rate of multi-purpose dam. It was calculated the probability distribution by selecting a typical water level stations and multipurpose dam of each basin. And the RSQM and RRQM were comparison and analysis to SPI and PDSI Index. These schemes can be objectively judged insufficient degree and drought conditions in water in real time. The RSQM and RSQM are meaning the supply potential of water resources and stress value of river environment. RRQM is mainly due to represent the adjusted value of downstream of multi-purpose dam. Accordingly it does not show the tendency of the representation of the drought to match exactly. However, RRQM is more directly represented about visually showing drought conditions

  3. Spatial and temporal characteristics of droughts in Luanhe River basin, China

    Science.gov (United States)

    Wang, Yixuan; Zhang, Ting; Chen, Xu; Li, Jianzhu; Feng, Ping

    2017-02-01

    The spatial and temporal characteristics of drought are investigated for Luanhe River basin, using monthly precipitation data from 26 stations covering the common period of 1958-2011. The spatial pattern of drought was assessed by applying principal component analysis (PCA) to the Standardized Precipitation Index (SPI) computed on 3- and 12-month time scales. In addition, annual SPI and seasonal SPIs (including spring SPI, summer SPI, autumn SPI, and winter SPI) were also defined and considered in this study to characterize seasonal and annual drought conditions, respectively. For all seven SPI cases, three distinctive sub-regions with different temporal evolutions of droughts are well identified, respectively, representing the southeast, middle, and northwest of the Luanhe River basin. The Mann-Kendall (MK) trend test with a trend-free pre-whitening (TFPW) procedure and Sen's method were used to determine the temporal trends in the annual and seasonal SPI time series. The continuous wavelet transform (CWT) was employed for further detecting the periodical features of drought condition in each sub-region. Results of MK and Sen's tests show a general tendency of intensification in summer drought over the entire basin, while a significant mitigating trend in spring drought. On the whole, an aggravating trend of inter-annual drought is discovered across the basin. Based on the CWT, the drought variability in the basin is generally dominated by 16- to 64-month cycles, and the 2- to 6-year cycles appear to be obvious when concerned with annual and seasonal droughts. Furthermore, a cross wavelet analysis was performed to examine the possible links between the drought conditions and large-scale climate patterns. The teleconnections of ENSO, NAO, PDO, and AMO show significant influences on the regional droughts principally concentrated in the 16- to 64-month period, maybe responsible for the physical causes of the cyclical behavior of drought occurrences. PDO and AMO also

  4. Drought Prediction for Socio-Cultural Stability Project

    Science.gov (United States)

    Peters-Lidard, Christa; Eylander, John B.; Koster, Randall; Narapusetty, Balachandrudu; Kumar, Sujay; Rodell, Matt; Bolten, John; Mocko, David; Walker, Gregory; Arsenault, Kristi; Rheingrover, Scott

    2014-01-01

    The primary objective of this project is to answer the question: "Can existing, linked infrastructures be used to predict the onset of drought months in advance?" Based on our work, the answer to this question is "yes" with the qualifiers that skill depends on both lead-time and location, and especially with the associated teleconnections (e.g., ENSO, Indian Ocean Dipole) active in a given region season. As part of this work, we successfully developed a prototype drought early warning system based on existing/mature NASA Earth science components including the Goddard Earth Observing System Data Assimilation System Version 5 (GEOS-5) forecasting model, the Land Information System (LIS) land data assimilation software framework, the Catchment Land Surface Model (CLSM), remotely sensed terrestrial water storage from the Gravity Recovery and Climate Experiment (GRACE) and remotely sensed soil moisture products from the Aqua/Advanced Microwave Scanning Radiometer - EOS (AMSR-E). We focused on a single drought year - 2011 - during which major agricultural droughts occurred with devastating impacts in the Texas-Mexico region of North America (TEXMEX) and the Horn of Africa (HOA). Our results demonstrate that GEOS-5 precipitation forecasts show skill globally at 1-month lead, and can show up to 3 months skill regionally in the TEXMEX and HOA areas. Our results also demonstrate that the CLSM soil moisture percentiles are a goof indicator of drought, as compared to the North American Drought Monitor of TEXMEX and a combination of Famine Early Warning Systems Network (FEWS NET) data and Moderate Resolution Imaging Spectrometer (MODIS)'s Normalizing Difference Vegetation Index (NDVI) anomalies over HOA. The data assimilation experiments produced mixed results. GRACE terrestrial water storage (TWS) assimilation was found to significantly improve soil moisture and evapotransportation, as well as drought monitoring via soil moisture percentiles, while AMSR-E soil moisture

  5. Multivariate assessment and attribution of droughts in Central Asia.

    Science.gov (United States)

    Li, Zhi; Chen, Yaning; Fang, Gonghuan; Li, Yupeng

    2017-05-02

    While the method for estimating the Palmer Drought Severity Index (PDSI) is now more closely aligned to key water balance components, a comprehensive assessment for measuring long-term droughts that recognizes meteorological, agro-ecological and hydrological perspectives and their attributions is still lacking. Based on physical approaches linked to potential evapotranspiration (PET), the PDSI in 1965-2014 showed a mixture of drying (42% of the land area) and wetting (58% of the land area) that combined to give a slightly wetting trend (0.0036 per year). Despite the smaller overall trend, there is a switch to a drying trend over the past decade (-0.023 per year). We designed numerical experiments and found that PDSI trend responding to the dramatic increase in air temperature and slight change in precipitation. The variabilities of meteorological and agro-ecological droughts were broadly comparable to various PDSI drought index. Interestingly, the hydrological drought was not completely comparable to the PDSI, which indicates that runoff in arid and semi-arid regions was not generated primarily from precipitation. Instead, fraction of glacierized areas in catchments caused large variations in the observed runoff changes.

  6. CONSIDERATIONS ON STREAMFLOW DROUGHT IN CENTRAL ROMANIAN PLAIN

    Directory of Open Access Journals (Sweden)

    ADINA-ELIZA CROITORU

    2011-03-01

    Full Text Available Considerations on Streamflow Drought In Central RomanianPlain. As one of the most important hydrological phenomenon in the area,streamflow drought was identified using daily discharge flow data series for 30years (1980-2009. The data were recorded in seven observation points located onsix rivers, in the central part of the Romanian Plain (between Olt and Argeşrivers. Some aspects of duration and severity of the hydrological drought eventswere calculated: number, average and maximum duration, daily average dischargeflow and streamflow deficit volume of hydrological drought events. Mann-Kendall test and Sen’s slope estimation for trends detection were applied in orderto analyze trends of those features in the studied region. As main conclusions:most part of the considered rivers show similar behavior with general increasingtrends of the most analyzed drought parameters; the only exception is Glavaciocriver, with decreasing slopes for the great majority of the parameters. For themean daily discharge flows, insignificant slopes were calculated.

  7. A preliminary study on drought events in Peninsular Malaysia

    Science.gov (United States)

    Zin, Wan Zawiah Wan; Nahrawi, Siti Aishah; Jemain, Abdul Aziz; Zahari, Marina

    2014-06-01

    In this research, the Standard Precipitation Index (SPI) is used to represent the dry condition in Peninsular Malaysia. To do this, data of monthly rainfall from 75 stations in Peninsular Malaysia is used to obtain the SPI values at scale one. From the SPI values, two drought characteristics that are commonly used to represent the dry condition in an area that is the duration and severity of a drought period are identified and their respective values calculated for every station. Spatial mappings are then used to identify areas which are more likely to be affected by longer and more severe drought condition from the results. As the two drought characteristics may be correlated with each other, the joint distribution of severity and duration of dry condition is considered. Bivariate copula model is used and five copula models were tested, namely, the Gumbel-Hougard, Clayton, Frank, Joe and Galambos copulas. The copula model, which best represents the relationship between severity and duration, is determined using Akaike information criterion. The results showed that the Joe and Clayton copulas are well-fitted by close to 60% of the stations under study. Based on the results on the most appropriate copula-based joint distribution for each station, some bivariate probabilistic properties of droughts can then be calculated, which will be continued in future research.

  8. SEASONAL DROUGHT DYNAMICS IN EL-BEHEIRA GOVERNORATE, EGYPT

    Directory of Open Access Journals (Sweden)

    Amr Mossad

    2014-01-01

    Full Text Available Drought is the most damaging climate-related hazards due to the prolonged absence of precipitation. Therefore, understanding the drought dynamics is important for irrigation water management to mitigate the negative impacts on agriculture. In this study, Standardized Precipitation Index (SPI and Standardized Precipitation Evapotranspiration Index (SPEI were used as effective tools for tracking the changes of water status occurred at five agro-meteorological stations (Etay Al Baroud, Wadi El-Natrun, Al Boseli, Badr and Nubariyah within El-Beheira governorate, Egypt. In addition, the overall water risk for agro-meteorological stations was estimated using the Aqueduct-GIS tool. The results clarified that Badr agro-meteorological station is representing the highest of water deficit by 96.6%, whereas, Al Boseli agro-meteorological station is representing the lowest water deficit by 86.9%. However, The SPI over El-Beheira region often confined in the near normal class, while the SPEI showed a notable increase of drought (SPEI = 0 to -4 in last 10 years of the analyses. The results suggested that El-Beheira governorate is moving toward the drought in general and Wadi El-Natrun and Nubariyah are the most drought affected areas in the future.

  9. Photosynthetic Physiological Characteristics of Gazania rigens L. Under Drought Stress

    Science.gov (United States)

    Gao, T. T.; Zheng, S. W.; Zhou, X. H.; Wang, D. X.; Lu, X. P.

    2016-08-01

    To investigate the responses of photosynthetic physiological characteristics of Gazania rigens L. to drought stress, the changes of three cultivars (‘Xingbai’, ‘XH’ and ‘Hongwen’) photosynthetic values under drought stress were determined via LI-6400 portable photosynthesis analyzer (LI-COR, USA), and the relationships between photosynthesis and drought resistance of each cultivar were analyzed. The results showed that, three cultivars net photosynthetic rate (Pn), stomatal conductance (Gs), transpiration rate (Tr), and light use efficiency (LUE) value indicated the trend of decreasing gradually and there existed significant reduction in Pn and Gs values. There were extremely negative significant correlations between drought stress treatment days and Pn, Gs, Tr, water use efficiency (WUE) and LUE values. A small amount of leaves began to turn soft and yellow after drought stress treatment for 10 days, but they could recover to grow quickly after rehydration. The Pn values of ‘Hongwen’ decreased quickly and changed in a large range, so it had a poor resistance; the Pn values of ‘Xingbai’ decreased slowly and changed in a small range, so it had a strong resistance; while the changes of their hybrids -‘XH’ were between its parents. This research would provide a theoretical basis for gazania resistance cultivar breeding and application in landscape.

  10. Carbon-Water Interactions during Warm Spring and Summer Drought

    Science.gov (United States)

    Wolf, Sebastian; Keenan, Trevor F.; Fisher, Joshua B.; Baldocchi, Dennis D.; Desai, Ankur R.; Richardson, Andrew. D.; Scott, Russell L.; Law, Beverly E.; Litvak, Marcy E.; Brunsell, Nathaniel A.; Peters, Wouter; van der Laan-Luijkx, Ingrid T.

    2017-04-01

    Warmer temperatures during spring and a higher prevalence of drought during summer are projected in a changing climate. In 2012, the US experienced the warmest spring on record and the most severe drought since the Dust Bowl period. It is crucial to understand the impact of such events on carbon-water interactions in terrestrial ecosystems to better predict their response in a future climate. We combined an extensive network of direct ecosystem flux measurements with satellite remote sensing and atmospheric inverse modelling to quantify the impact of the warmer spring and summer drought on biosphere-atmosphere carbon and water exchange in 2012 across the US. We found that earlier vegetation activity increased spring carbon uptake and compensated for the reduced uptake during the summer drought, which mitigated the impact on net annual carbon uptake. The early phenological development in the Northeast played a major role for the continental-scale carbon balance in 2012. The warm spring also depleted soil water resources earlier, and thus exacerbated water limitations during summer. Our results show that the detrimental effects of severe summer drought on ecosystem carbon storage can be mitigated by warming-induced increases in spring carbon uptake. However, the positive carbon cycle effect of warm spring enhances water limitations and can increase summer heating through biosphere-atmosphere feedbacks.

  11. Role of ocean evaporation in California droughts and floods

    Science.gov (United States)

    Wei, Jiangfeng; Jin, Qinjian; Yang, Zong-Liang; Dirmeyer, Paul A.

    2016-06-01

    Since winter 2011, a record-breaking drought has occurred in California. Studies found that the drought is mainly caused by a persistent high-pressure system off the U.S. West Coast, which is linked to Pacific sea surface temperature anomalies. The water cycles associated with the droughts and floods are still not clearly understood. Here we show that the atmospheric circulation off the West Coast not only controls the atmospheric convergence and formation of precipitation but also largely determines surface wind speed, which further affects the evaporation over the eastern North Pacific, the major evaporative moisture source for California precipitation. Because of this mechanism, the ocean evaporation over the eastern North Pacific has been reduced during the recent drought. However, the ocean evaporation anomalies have little direct influence on California precipitation, especially during dry years, mainly because of their weak amplitudes. The California droughts cannot be readily attributed to the reduced ocean evaporation. The association between increased Pacific evaporation and floods over California is somewhat stronger.

  12. A Medieval Perspective of Historical California and Nevada Droughts

    Science.gov (United States)

    Hatchett, B.; Boyle, D. P.; Garner, C.; Putnam, A. E.; Bassett, S.; Kaplan, M.

    2015-12-01

    Dryland closed basin lake systems are ideal natural laboratories for model-proxy evaluations of how climate change alters the regional water balance. We use an existing water balance and lake-evaporation model of the Walker Lake Basin, a 1600-year reconstruction of Walker Lake shoreline elevations, and fields from the 20th Century Reanalysis to provide the following insights: 1) The three major historical (post-Little Ice Age) droughts observed in the California-western Nevada region (the 1930s, 1987-1992, and 2012-2015) are comparable in magnitude to the severe droughts of the Medieval Climate Anomaly but not in duration; 2) The atmospheric circulation anomalies associated with these events include poleward deflections of storm tracks and reduced moisture transport into the region; 3) To produce the Medieval lowstands of Walker Lake, precipitation and circulation anomalies comparable to historical droughts must persist for a minimum of 50 years. These insights show how severe historical and ongoing droughts in this region are within the range of natural variability. The 2012-2015 drought is also shown to be exacerbated by recent positive temperature anomalies that may be outside of the range of natural variability. These results can help to improve future water resource planning for the western United States, where ongoing and future changes in climate leading to increased water scarcity will have significant negative impacts on socioeconomic and ecological systems.

  13. Urban responses to restrictive conservation policy during drought

    Science.gov (United States)

    Palazzo, Joseph; Liu, Owen R.; Stillinger, Timbo; Song, Runsheng; Wang, Ying; Hiroyasu, Elizabeth H. T.; Zenteno, Jose; Anderson, Sarah; Tague, Christina

    2017-05-01

    With climate change, the extent, severity, and frequency of droughts around the world are expected to increase. This study analyzed the ability of water districts to meet mandatory urban water conservation targets, which are a common policy response to drought. During California's recent record-breaking drought, a 25% state-wide use reduction objective was set and met. However, only 50% of urban water districts analyzed in this study reached their individual conservation target, which offers an opportunity to evaluate the factors associated with successful water use reduction. The findings show that the inclusion of water districts in the polycentric import structure may improve water conservation, but that source diversity may offer water districts a perceived buffer from the need for immediate water use reductions. Drought severity and lower median incomes are associated with greater water conservation, and conservation varies by hydrologic region. This analysis offers insights into institutional design and suggests that local biophysical and economic conditions shape responses in systematic ways that should be addressed by public policy responses to drought.

  14. General mechanisms of drought response and their application in drought resistance improvement in plants.

    Science.gov (United States)

    Fang, Yujie; Xiong, Lizhong

    2015-02-01

    Plants often encounter unfavorable environmental conditions because of their sessile lifestyle. These adverse factors greatly affect the geographic distribution of plants, as well as their growth and productivity. Drought stress is one of the premier limitations to global agricultural production due to the complexity of the water-limiting environment and changing climate. Plants have evolved a series of mechanisms at the morphological, physiological, biochemical, cellular, and molecular levels to overcome water deficit or drought stress conditions. The drought resistance of plants can be divided into four basic types-drought avoidance, drought tolerance, drought escape, and drought recovery. Various drought-related traits, including root traits, leaf traits, osmotic adjustment capabilities, water potential, ABA content, and stability of the cell membrane, have been used as indicators to evaluate the drought resistance of plants. In the last decade, scientists have investigated the genetic and molecular mechanisms of drought resistance to enhance the drought resistance of various crops, and significant progress has been made with regard to drought avoidance and drought tolerance. With increasing knowledge to comprehensively decipher the complicated mechanisms of drought resistance in model plants, it still remains an enormous challenge to develop water-saving and drought-resistant crops to cope with the water shortage and increasing demand for food production in the future.

  15. Hysteresis of magnetostructural transitions: Repeatable and non-repeatable processes

    Energy Technology Data Exchange (ETDEWEB)

    Provenzano, Virgil [National Institute of Standards and Technology, Gaithersburg, MD 20899 (United States); Della Torre, Edward; Bennett, Lawrence H. [Department of Electrical and Computer Engineering, The George Washington University, Washington, DC 20052 (United States); ElBidweihy, Hatem, E-mail: Hatem@gwmail.gwu.edu [Department of Electrical and Computer Engineering, The George Washington University, Washington, DC 20052 (United States)

    2014-02-15

    The Gd{sub 5}Ge{sub 2}Si{sub 2} alloy and the off-stoichiometric Ni{sub 50}Mn{sub 35}In{sub 15} Heusler alloy belong to a special class of metallic materials that exhibit first-order magnetostructural transitions near room temperature. The magnetic properties of this class of materials have been extensively studied due to their interesting magnetic behavior and their potential for a number of technological applications such as refrigerants for near-room-temperature magnetic refrigeration. The thermally driven first-order transitions in these materials can be field-induced in the reverse order by applying a strong enough field. The field-induced transitions are typically accompanied by the presence of large magnetic hysteresis, the characteristics of which are a complicated function of temperature, field, and magneto-thermal history. In this study we show that the virgin curve, the major loop, and sequentially measured MH loops are the results of both repeatable and non-repeatable processes, in which the starting magnetostructural state, prior to the cycling of field, plays a major role. Using the Gd{sub 5}Ge{sub 2}Si{sub 2} and Ni{sub 50}Mn{sub 35}In{sub 15} alloys, as model materials, we show that a starting single phase state results in fully repeatable processes and large magnetic hysteresis, whereas a mixed phase starting state results in non-repeatable processes and smaller hysteresis.

  16. Simultaneous expression of regulatory genes associated with specific drought-adaptive traits improves drought adaptation in peanut.

    Science.gov (United States)

    Ramu, Vemanna S; Swetha, Thavarekere N; Sheela, Shekarappa H; Babitha, Chandrashekar K; Rohini, Sreevathsa; Reddy, Malireddy K; Tuteja, Narendra; Reddy, Chandrashekar P; Prasad, Trichi Ganesh; Udayakumar, Makarla

    2016-03-01

    Adaptation of crops to drought-prone rain-fed conditions can be achieved by improving plant traits such as efficient water mining (by superior root characters) and cellular-level tolerance mechanisms. Pyramiding these drought-adaptive traits by simultaneous expression of genes regulating drought-adaptive mechanisms has phenomenal relevance in improving stress tolerance. In this study, we provide evidence that peanut transgenic plants expressing Alfalfa zinc finger 1 (Alfin1), a root growth-associated transcription factor gene, Pennisetum glaucum heat-shock factor (PgHSF4) and Pea DNA helicase (PDH45) involved in protein turnover and protection showed improved tolerance, higher growth and productivity under drought stress conditions. Stable integration of all the transgenes was noticed in transgenic lines. The transgenic lines showed higher root growth, cooler crop canopy air temperature difference (less CCATD) and higher relative water content (RWC) under drought stress. Low proline levels in transgenic lines substantiate the maintenance of higher water status. The survival and recovery of transgenic lines was significantly higher under gradual moisture stress conditions with higher biomass. Transgenic lines also showed significant tolerance to ethrel-induced senescence and methyl viologen-induced oxidative stress. Several stress-responsive genes such as heat-shock proteins (HSPs), RING box protein-1 (RBX1), Aldose reductase, late embryogenesis abundant-5 (LEA5) and proline-rich protein-2 (PRP2), a gene involved in root growth, showed enhanced expression under stress in transgenic lines. Thus, the simultaneous expression of regulatory genes contributing for drought-adaptive traits can improve crop adaptation and productivity under water-limited conditions.

  17. ABA receptor PYL9 promotes drought resistance and leaf senescence.

    Science.gov (United States)

    Zhao, Yang; Chan, Zhulong; Gao, Jinghui; Xing, Lu; Cao, Minjie; Yu, Chunmei; Hu, Yuanlei; You, Jun; Shi, Haitao; Zhu, Yingfang; Gong, Yuehua; Mu, Zixin; Wang, Haiqing; Deng, Xin; Wang, Pengcheng; Bressan, Ray A; Zhu, Jian-Kang

    2016-02-16

    Drought stress is an important environmental factor limiting plant productivity. In this study, we screened drought-resistant transgenic plants from 65 promoter-pyrabactin resistance 1-like (PYL) abscisic acid (ABA) receptor gene combinations and discovered that pRD29A::PYL9 transgenic lines showed dramatically increased drought resistance and drought-induced leaf senescence in both Arabidopsis and rice. Previous studies suggested that ABA promotes senescence by causing ethylene production. However, we found that ABA promotes leaf senescence in an ethylene-independent manner by activating sucrose nonfermenting 1-related protein kinase 2s (SnRK2s), which subsequently phosphorylate ABA-responsive element-binding factors (ABFs) and Related to ABA-Insensitive 3/VP1 (RAV1) transcription factors. The phosphorylated ABFs and RAV1 up-regulate the expression of senescence-associated genes, partly by up-regulating the expression of Oresara 1. The pyl9 and ABA-insensitive 1-1 single mutants, pyl8-1pyl9 double mutant, and snrk2.2/3/6 triple mutant showed reduced ABA-induced leaf senescence relative to the WT, whereas pRD29A::PYL9 transgenic plants showed enhanced ABA-induced leaf senescence. We found that leaf senescence may benefit drought resistance by helping to generate an osmotic potential gradient, which is increased in pRD29A::PYL9 transgenic plants and causes water to preferentially flow to developing tissues. Our results uncover the molecular mechanism of ABA-induced leaf senescence and suggest an important role of PYL9 and leaf senescence in promoting resistance to extreme drought stress.

  18. Global trends and patterns of drought from space

    Science.gov (United States)

    Damberg, Lisa; AghaKouchak, Amir

    2014-08-01

    This paper analyzes changes in areas under droughts over the past three decades and alters our understanding of how amplitude and frequency of droughts differ in the Southern Hemisphere (SH) and Northern Hemisphere (NH). Unlike most previous global-scale studies that have been based on climate models, this study is based on satellite gauge-adjusted precipitation observations. Here, we show that droughts in terms of both amplitude and frequency are more variable over land in the SH than in the NH. The results reveal no significant trend in the areas under drought over land in the past three decades. However, after investigating land in the NH and the SH separately, the results exhibit a significant positive trend in the area under drought over land in the SH, while no significant trend is observed over land in the NH. We investigate the spatial patterns of the wetness and dryness over the past three decades, and we show that several regions, such as the southwestern United States, Texas, parts of the Amazon, the Horn of Africa, northern India, and parts of the Mediterranean region, exhibit a significant drying trend. The global trend maps indicate that central Africa, parts of southwest Asia (e.g., Thailand, Taiwan), Central America, northern Australia, and parts of eastern Europe show a wetting trend during the same time span. The results of this satellite-based study disagree with several model-based studies which indicate that droughts have been increasing over land. On the other hand, our findings concur with some of the observation-based studies.

  19. 玉米芽期抗旱性研究初报%Pilot Study of Drought Resistance for Maize at Budding Stage

    Institute of Scientific and Technical Information of China (English)

    张振文; 陈丽珍; 郑永清; 吴传毅

    2008-01-01

    The drought resistances of 44 maize germplasms at budding stage were studied with 19.2% polyethylene glycol (PEG-6000) in order to provide new germplasm resource for drought resistance breeding of maize. The results showed there were five extremely high drought resistance germplasms, 20 germplasms with high drought resistance, and 19 germplasms with medium drought resistance. The significance testing was also used to demonstrate that the germination index (GI) and germination of drought resistance index (GDRI) of N4, N54-1 and Wuming No.1 were dramatically remarkable than others. The conclusion was that the 44 maize germplasm had good drought resistance and could be used as germplasm resource of the drought resistance breeding of maize, which had a great value of development and utilization.

  20. Drought Analysis of the Haihe River Basin Based on GRACE Terrestrial Water Storage

    Science.gov (United States)

    Wang, Jianhua; Jiang, Dong; Huang, Yaohuan; Wang, Hao

    2014-01-01

    The Haihe river basin (HRB) in the North China has been experiencing prolonged, severe droughts in recent years that are accompanied by precipitation deficits and vegetation wilting. This paper analyzed the water deficits related to spatiotemporal variability of three variables of the gravity recovery and climate experiment (GRACE) derived terrestrial water storage (TWS) data, precipitation, and EVI in the HRB from January 2003 to January 2013. The corresponding drought indices of TWS anomaly index (TWSI), precipitation anomaly index (PAI), and vegetation anomaly index (AVI) were also compared for drought analysis. Our observations showed that the GRACE-TWS was more suitable for detecting prolonged and severe droughts in the HRB because it can represent loss of deep soil water and ground water. The multiyear droughts, of which the HRB has sustained for more than 5 years, began in mid-2007. Extreme drought events were detected in four periods at the end of 2007, the end of 2009, the end of 2010, and in the middle of 2012. Spatial analysis of drought risk from the end of 2011 to the beginning of 2012 showed that human activities played an important role in the extent of drought hazards in the HRB. PMID:25202732

  1. More grain per drop of water: Screening rice genotype for physiological parameters of drought tolerance

    Science.gov (United States)

    Massanelli, J.; Meadows-McDonnell, M.; Konzelman, C.; Moon, J. B.; Kumar, A.; Thomas, J.; Pereira, A.; Naithani, K. J.

    2016-12-01

    Meeting agricultural water demands is becoming progressively difficult due to population growth and changes in climate. Breeding stress-resilient crops is a viable solution, as information about genetic variation and their role in stress tolerance is becoming available due to advancement in technology. In this study we screened eight diverse rice genotypes for photosynthetic capacity under greenhouse conditions. These include the Asian rice (Oryza sativa) genotypes, drought sensitive Nipponbare, and a transgenic line overexpressing the HYR gene in Nipponbare; six genotypes (Vandana, Bengal, Nagina-22, Glaberrima, Kaybonnet, Ai Chueh Ta Pai Ku) and an African rice O. glaberrima, all selected for varying levels of drought tolerance. We collected CO2 and light response curve data under well-watered and simulated drought conditions in greenhouse. From these curves we estimated photosynthesis model parameters, such as the maximum carboxylation rate (Vcmax), the maximum electron transport rate (Jmax), the maximum gross photosynthesis rate, daytime respiration (Rd), and quantum yield (f). Our results suggest that O. glaberrima and Nipponbare were the most sensitive to drought because Vcmax and Pgmax declined under drought conditions; other drought tolerant genotypes did not show significant changes in these model parameters. Our integrated approach, combining genetic information and photosynthesis modeling, shows promise to quantify drought response parameters and improve crop yield under drought stress conditions.

  2. Quantitative risk assessment of the effects of drought on extreme temperature in eastern China

    Science.gov (United States)

    Hao, Zengchao; Hao, Fanghua; Singh, Vijay P.; Ouyang, Wei

    2017-09-01

    Hot extremes may lead to disastrous impacts on human health and agricultural production. Previous studies have revealed the feedback between drought and hot extremes in large regions of eastern China, while quantifying the impact of antecedent drought on hot extremes has been limited. This study aims at quantitatively assessing the risk of extreme temperature conditioned on the antecedent drought condition represented by Standardized Precipitation Index (SPI) during summer time in eastern China. A copula-based model is proposed to construct the joint probability distribution of extreme temperature and drought based on 6 month SPI (SPI6). Accordingly, the conditional probability distribution is employed to quantify impacts of antecedent dry (and wet) conditions on the exceedance probability of extreme temperature. Results show that the likelihood of extreme temperature exceeding high quantiles is higher given antecedent dry conditions than that given antecedent wet conditions in large regions from southwestern to northeastern China. Specifically, the conditional probability difference of temperature exceeding 80th percentile given SPI6 lower than or equal to -0.5 and SPI6 higher than 0.5 is around 0.2-0.3. The case study of the 2006 summer hot extremes and drought in Sichuan and Chongqing region shows that the conditional return period of extreme temperature conditioned on antecedent drought is around 5-50 years shorter than univariate return period. These results quantify the impact of antecedent drought on subsequent extreme temperature and highlight the important role of antecedent drought in intensifying hot extremes in these regions.

  3. Evaluation of PERSIANN-CDR for Meteorological Drought Monitoring over China

    Directory of Open Access Journals (Sweden)

    Hao Guo

    2016-05-01

    Full Text Available In this paper, Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks–Climate Data Record (PERSIANN-CDR is analyzed for the assessment of meteorological drought. The evaluation is conducted over China at 0.5° spatial resolution against a ground-based gridded China monthly Precipitation Analysis Product (CPAP from 1983 to 2014 (32 years. The Standardized Precipitation Index (SPI at various time scales (1 month to 12 months is calculated for detecting drought events. The results show that PERSIANN-CDR depicts similar drought behavior as the ground-based CPAP in terms of capturing the spatial and temporal patterns of drought events over eastern China, where the intensity of gauge networks and the frequency of droughts are high. 6-month SPI shows the best agreement with CPAP in identifying drought months. However, large differences between PERSIANN-CDR and CPAP in depicting drought patterns and identifying specific drought events are found over northwestern China, particularly in Xinjiang and Qinghai-Tibet Plateau region. Factors behind this may be due to the relatively sparse gauge networks, the complicated terrain and the performance of PERSIANN algorithm.

  4. Daily weather generator with drought properties by copulas and standardized precipitation indices.

    Science.gov (United States)

    Hong, Nien-Ming; Lee, Tsung-Yu; Chen, Yun-Ju

    2016-06-01

    The weather generator is an essential process in water resource assessment. Most weather generators focus on extreme rainfall events and rainfall amounts in a relatively short time scale. However, drought events often last more than several months, which conventional weather generators hardly generate. Conventional weather generators assume that monthly rainfalls are independent, skewing drought event generation. The purpose of this study is to construct a weather generator with improved drought property generation, combining with monthly rainfall data from conventional weather generators and characteristics of standardized precipitation indices. The proposed weather generators employs four drought parameters, namely starting month, duration, average, and minimum standardized precipitation indices, generated using a copula method. Analytical results show that the four parameters generated by the copula method are consistent with historical records. The proposed weather generator overcomes the limitation of conventional weather generators and can generate both rainfall and drought properties. The results also indicate that the assumption of monthly independence in drought generation can cause underestimated occurrence and duration of drought events. The proposed generator is also demonstrated for climate change assessment. The analytical results show that the uncertainties from the selection of weather generators are even higher than those from the selections of global circulation models while applying to water shortage assessment. We therefore suggest that weather generators should consider drought characteristics which can be measured using the standardized precipitation index to reduce the uncertainty.

  5. Drought Analysis of the Haihe River Basin Based on GRACE Terrestrial Water Storage

    Directory of Open Access Journals (Sweden)

    Jianhua Wang

    2014-01-01

    Full Text Available The Haihe river basin (HRB in the North China has been experiencing prolonged, severe droughts in recent years that are accompanied by precipitation deficits and vegetation wilting. This paper analyzed the water deficits related to spatiotemporal variability of three variables of the gravity recovery and climate experiment (GRACE derived terrestrial water storage (TWS data, precipitation, and EVI in the HRB from January 2003 to January 2013. The corresponding drought indices of TWS anomaly index (TWSI, precipitation anomaly index (PAI, and vegetation anomaly index (AVI were also compared for drought analysis. Our observations showed that the GRACE-TWS was more suitable for detecting prolonged and severe droughts in the HRB because it can represent loss of deep soil water and ground water. The multiyear droughts, of which the HRB has sustained for more than 5 years, began in mid-2007. Extreme drought events were detected in four periods at the end of 2007, the end of 2009, the end of 2010, and in the middle of 2012. Spatial analysis of drought risk from the end of 2011 to the beginning of 2012 showed that human activities played an important role in the extent of drought hazards in the HRB.

  6. The European 2015 drought from a climatological perspective

    Science.gov (United States)

    Ionita-Scholz, Monica; Tallaksen, Lena; Kingston, Daniel; Stagge, James

    2016-04-01

    ) was characterized by large negative SST anomalies in the central North Atlantic Ocean and large positive SST anomalies in the Mediterranean basin. The negative Atlantic SST anomaly was first evident in September 2014, with June - August 2015 within the top 10 coldest summers in this region in the last 150 years. The SST dipole-like anomalies between the central Atlantic and the Mediterranean Sea suggest a possible "atmospheric teleconnection" between the two areas, which in turn affected the drought conditions over Europe. The 2015 summer drought shows resemblances with the 2003 summer drought in terms of spatial extent and consequences, but the two extreme events were driven by different atmospheric and oceanic drivers.

  7. Reconstructing and analyzing China's fifty-nine year (1951–2009 drought history using hydrological model simulation

    Directory of Open Access Journals (Sweden)

    Z. Y. Wu

    2011-09-01

    Full Text Available The 1951–2009 drought history of China is reconstructed using daily soil moisture values generated by the Variable Infiltration Capacity (VIC land surface macroscale hydrology model. VIC is applied over a grid of 10 458 points with a spatial resolution of 30 km × 30 km, and is driven by observed daily maximum and minimum air temperature and precipitation from 624 long-term meteorological stations. The VIC soil moisture is used to calculate the Soil Moisture Anomaly Percentage Index (SMAPI, which can be used as a measure of the severity of agricultural drought on a global basis. We have developed a SMAPI-based drought identification procedure for practical uses in the identification of both grid point and regional drought events. As a result, a total of 325 regional drought events varying in time and strength are identified from China's nine drought study regions. These drought events can thus be assessed quantitatively at different spatial and temporal scales. The result shows that the severe drought events of 1978, 2000 and 2006 are well reconstructed, which indicates that the SMAPI is capable of identifying the onset of a drought event, its progression, as well as its termination. Spatial and temporal variations of droughts in China's nine drought study regions are studied. Our result shows that on average, up to 30% of the total area of China is prone to drought. Regionally, an upward trend in drought-affected areas has been detected in three regions (Inner Mongolia, Northeast and North from 1951–2009. However, the decadal variability of droughts has been weak in the rest of the five regions (South, Southwest, East, Northwest, and Tibet. Xinjiang has even been showing steadily wetter since the 1950s. Two regional dry centres are discovered in China as the result of a combined analysis on the occurrence of drought events from both grid points and drought study regions. The first centre is located in the area partially covered by the North

  8. Drought footprint on European ecosystems between 1999 and 2010 assessed by remotely sensed vegetation phenology and productivity.

    Science.gov (United States)

    Ivits, Eva; Horion, Stephanie; Fensholt, Rasmus; Cherlet, Michael

    2014-02-01

    Drought affects more people than any other natural disaster but there is little understanding of how ecosystems react to droughts. This study jointly analyzed spatio-temporal changes of drought patterns with vegetation phenology and productivity changes between 1999 and 2010 in major European bioclimatic zones. The Standardized Precipitation and Evapotranspiration Index (SPEI) was used as drought indicator whereas changes in growing season length and vegetation productivity were assessed using remote sensing time-series of Normalized Difference Vegetation Index (NDVI). Drought spatio-temporal variability was analyzed using a Principal Component Analysis, leading to the identification of four major drought events between 1999 and 2010 in Europe. Correspondence Analysis showed that at the continental scale the productivity and phenology reacted differently to the identified drought events depending on ecosystem and land cover. Northern and Mediterranean ecosystems proved to be more resilient to droughts in terms of vegetation phenology and productivity developments. Western Atlantic regions and Eastern Europe showed strong agglomerations of decreased productivity and shorter vegetation growing season length, indicating that these ecosystems did not buffer the effects of drought well. In a climate change perspective, increase in drought frequency or intensity may result in larger impacts over these ecosystems, thus management and adaptation strategies should be strengthened in these areas of concerns.

  9. Drought in a human-modified world: reframing drought definitions, understanding, and analysis approaches

    Science.gov (United States)

    Van Loon, Anne F.; Stahl, Kerstin; Di Baldassarre, Giuliano; Clark, Julian; Rangecroft, Sally; Wanders, Niko; Gleeson, Tom; Van Dijk, Albert I. J. M.; Tallaksen, Lena M.; Hannaford, Jamie; Uijlenhoet, Remko; Teuling, Adriaan J.; Hannah, David M.; Sheffield, Justin; Svoboda, Mark; Verbeiren, Boud; Wagener, Thorsten; Van Lanen, Henny A. J.

    2016-09-01

    In the current human-modified world, or Anthropocene, the state of water stores and fluxes has become dependent on human as well as natural processes. Water deficits (or droughts) are the result of a complex interaction between meteorological anomalies, land surface processes, and human inflows, outflows, and storage changes. Our current inability to adequately analyse and manage drought in many places points to gaps in our understanding and to inadequate data and tools. The Anthropocene requires a new framework for drought definitions and research. Drought definitions need to be revisited to explicitly include human processes driving and modifying soil moisture drought and hydrological drought development. We give recommendations for robust drought definitions to clarify timescales of drought and prevent confusion with related terms such as water scarcity and overexploitation. Additionally, our understanding and analysis of drought need to move from single driver to multiple drivers and from uni-directional to multi-directional. We identify research gaps and propose analysis approaches on (1) drivers, (2) modifiers, (3) impacts, (4) feedbacks, and (5) changing the baseline of drought in the Anthropocene. The most pressing research questions are related to the attribution of drought to its causes, to linking drought impacts to drought characteristics, and to societal adaptation and responses to drought. Example questions include (i) What are the dominant drivers of drought in different parts of the world? (ii) How do human modifications of drought enhance or alleviate drought severity? (iii) How do impacts of drought depend on the physical characteristics of drought vs. the vulnerability of people or the environment? (iv) To what extent are physical and human drought processes coupled, and can feedback loops be identified and altered to lessen or mitigate drought? (v) How should we adapt our drought analysis to accommodate changes in the normal situation (i.e. what

  10. Comparison of drought indicators derived from multiple data sets over Africa

    Science.gov (United States)

    Naumann, G.; Dutra, E.; Barbosa, P.; Pappenberger, F.; Wetterhall, F.; Vogt, J. V.

    2014-05-01

    Drought monitoring is a key component to mitigate impacts of droughts. Lack of reliable and up-to-date precipitation data sets is a common challenge across the globe. This study investigates different data sets and drought indicators on their capability to improve drought monitoring in Africa. The study was performed for four river basins located in different climatic regions (the Oum er-Rbia in Morocco, the Blue Nile in eastern Africa, the Upper Niger in western Africa, and the Limpopo in southeastern Africa) as well as the Greater Horn of Africa. The five precipitation data sets compared are the ECMWF ERA-Interim reanalysis, the Tropical Rainfall Measuring Mission satellite monthly rainfall product 3B-43, the Global Precipitation Climatology Centre gridded precipitation data set, the Global Precipitation Climatology Project Global Monthly Merged Precipitation Analyses, and the Climate Prediction Center Merged Analysis of Precipitation. The set of drought indicators used includes the Standardized Precipitation Index, the Standardized Precipitation-Evaporation Index, and Soil Moisture Anomalies. A comparison of the annual cycle and monthly precipitation time series shows a good agreement in the timing of the rainy seasons. The main differences between the data sets are in the ability to represent the magnitude of the wet seasons and extremes. Moreover, for the areas affected by drought, all the drought indicators agree on the time of drought onset and recovery although there is disagreement on the extent of the affected area. In regions with limited rain gauge data the estimation of the different drought indicators is characterized by a higher uncertainty. Further comparison suggests that the main source of differences in the computation of the drought indicators is the uncertainty in the precipitation data sets rather than the estimation of the distribution parameters of the drought indicators.

  11. Multi-timescale Drought Variations based on standardized precipitation index in China during past 52 years

    Science.gov (United States)

    Wang, su ping; jie Zhang, cun; Li, yao hui; Feng, jianying; Wang, jinsong

    2016-04-01

    Based on daily precipitation data from 566 weather stations during 1960 to 2011 , the multi-timescale variations of drought in China were analyzed by using Standardized Precipitation Index. The results showed that there existed a northeast to southwest drought belt in China in recent 52 years. The climate in Northeast China, North China, eastern Inner Mongolia, east of Northwest China and Southwest China was becoming dry. Meanwhile it became significant wetter in Northern Xinjiang, central Qinghai and north central Tibet. The drought trend in North China mainly happened in summer, and drought in Northeast and Southwest occurred in summer and autumn, in the middle and lower reaches of the Yangtze River and the east part of Northwest it was mainly in spring and autumn. In Northeast China, the drought days in 1970s and 2000 - 2011 were more than other decades, and it were fewer in 1960s. In North China and the east of Northwest China, the driest decade was 1990s, and it was wetter from 1960s to 1980s. Southwest China experienced more droughts after 2000, and fewer in 1960s and 1970s. In the middle and lower reaches of Yangtze River .drought days were more in 1960s and after 2000, and fewer in 1980s. In 1960s, the high occurrence frequency of drought was in the west and middle of Northwest China and the middle and lower reaches of Yangtze River. In 1970s,the droughts frequently occurred in Northeast and the west of Northwest. In 1980s,drought events mainly took place in North China, Huang Huai plain, the west and middle part of inner Mongolia and east of Southwest respectively. In 1990s,the areas with high occurrence were transferred to the southeast of Northwest, North China, and Huang Huai, Jiang Huai, Jiang Han plain. After 2000, drought frequently occurred in Northeast, the middle and lower reaches of Yangtze River and east part of Inner Mongolia, Northwest and Southwest China.

  12. Impacts of European drought events

    NARCIS (Netherlands)

    Stahl, Kerstin; Kohn, Irene; Blauhut, Veit; Loon, Van Anne F.; Melsen, Lieke A.; Lanen, van Henny A.J.

    2016-01-01

    Drought is a natural hazard that can cause a wide range of impacts affecting the environment, society, and the economy. Providing an impact assessment and reducing vulnerability to these impacts for regions beyond the local scale, spanning political and sectoral boundaries, requires systematic an

  13. Remote Sensing Technologies Mitigat