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Sample records for changjiang yangtze river

  1. Oxygen depletion off the Changjiang (Yangtze River)Estuary

    Institute of Scientific and Technical Information of China (English)

    LI; Daoji; (李道季); ZHANG; Jing; (张经); HUANG; Daji; (黄大吉); WU; Ying; (吴莹); LIANG; Jun; (梁俊)

    2002-01-01

    In a survey on the Yellow Sea and the East China Sea on August 20-30 of 1999, we found a hypoxic zone (<2 mg/L) of 13700 km2 with an average thickness of 20m at the bottom of the Changjiang (Yangtze River) Estuary, with an oxygen minimum value of 1 mg/L. The extension of the dissolved oxygen deficiency extended to the 100m isobath in a southeastward direction along the bottom of the continental shelf of the East China Sea. During the last two decades, the minimum dissolved oxygen values in the low oxygen region of the Changjiang Estuary have decreased from 2.85 mg/L to 1 mg/L. In the hypoxic zone, the apparent oxygen utilization (AOU) was 5.8 mg/L and the total oxygen depletion approximately 1.59×106 t. The strong halocline above the hypoxic zone, as a result of affluent water from the Changjiang, Taiwan Warm Current (TWC), and the high concentrations of particle organic carbon (POC) and nitrogen (PON) are the major factors causing the formation of the hypoxic zone. The POC: PON ratios and nutrient concentration distributions in the hypoxic zone suggest that the oxygen deficiency in the bottom water during the summer in the East China Sea off the Changjiang is the result of organic carbon production enhanced by nutrients from the Changjiang and fluvial organic matter input, followed by a shift in regeneration of nutrients in the East China Sea.

  2. Assessment of trophic status in Changjiang (Yangtze) River estuary

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The integrated methodology for the assessment of estuarine trophic status (ASSETS),which was extended and refined from the United States National Estuarine Eutrophication Assessment (NEEA), is a multi-parameter assessment system and has been widely used in eutrophication assessment in estuarine and coastal waters. The ASSETS was applied to evaluate the trophic status of the Changjiang (Yangtze) River estuary, one of the largest estuaries in the world. The following main results were obtained: (i) The estuarine export potential is "moderate susceptibility" due to the "moderate" dilution potential and "moderate" flushing potential; (ii) The overall human influence (OHI) index classified the impact of nutrients in the system as "high" due to the high level of nutrient discharge by the river which channels anthropogenic impacts in the catchments to the estuarine system; (iii) The overall eutrophic condition (OEC) in the estuary was classified into the "high" category due to frequent occurrence of nuisance and toxic algal blooms in the mixing and seawater zones; (iv) Since the nutrient loadings (e.g.,DIN) in the river is expected to continue to increase in the near future following the population increase and rapid economic growth throughout the drainage basin, the nutrient-related symptoms in the estuary are likely to substantially worsen, which leads to the "worsen high" category for the definition of future outlook (DFO). The combinations of the three components (i.e., OHI, OEC, and DFO) lead to an overall grade as "bad" for the trophic status in the Changjiang River estuary.

  3. Sources of organic matter in Changjiang (Yangtze River) bed sediments : Preliminary insights from organic geochemical proxies

    NARCIS (Netherlands)

    Li, Zhongqiao; Peterse, Francien; Wu, Ying; Bao, Hongyan; Eglinton, Timothy I.; Zhang, Jing

    2015-01-01

    Insight into the content and composition of organic carbon (OC) in river systems contributes to our understanding of the global carbon cycle. The Changjiang (Yangtze River) plays a significant role in global carbon and hydrological cycles, as it is an important supplier of sediment, nutrients and OC

  4. Human impacts on the large world rivers: Would the Changjiang (Yangtze River) be an illustration?

    Science.gov (United States)

    Zhang, J.; Zhang, Z. F.; Liu, S. M.; Wu, Y.; Xiong, H.; Chen, H. T.

    1999-12-01

    The "Three Gorges Project" (TGP) in the upstream of Changjiang (Yangtze River) has resulted in great concern of scientific society and public conversations on the economic, environmental, and human health issues. Data of nutrients from main stream and 15 large tributaries indicate that Changjiang receives a large part of its nutrient burden from the drainage area upstream the "Three Gorges Dam" (TGD). A model calculation shows that the construction of TGD may cause further eutrophication in the upstream region with phosphate as a limiting factor relative to nitrogen for photosynthesis. The estimated carbon fixation within the reservoir may equal to 10-20% of the actual particulate organic carbon (POC) budget for the Changjiang. Taking into account the fact that dissolved inorganic nitrogen (DlN) in the Changjiang has increased by a factor of 2 in the last 10-20 years, the expected N:P ratio of the river would reach 300-400 after the year 2010. Such a change in nutrient and organic carbon budgets of the Changjiang will significantly influence the environment and health of ecosystems of the adjacent shelf region.

  5. Biogeochemistry of Nutrient Elements in the Changjiang (Yangtze River) Estuary

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Based on the biogeochemical studies on nutrient elements in the Changjiang estuary,the main results and recent progresses are reviewed in this paper, such as the nutrient fluxes into the sea, the mixing behaviors, the distribution characteristics and transportation as well as the biogeochemical behaviors of nutrients in the plume frontal region. The exploring directions and research emphases in the future are proposed.

  6. Historical records of eutrophication in Changjiang (Yangtze River estuary and its adjacent East China Sea

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    F. Cheng

    2012-06-01

    Full Text Available Two sediment cores from the Changjiang (Yangtze River estuary and its adjacent East China Sea were collected and studied for eutrophication history using paleoecological records of environmental changes over the last century. A multiproxy approach by using biological and geochemical analyses revealed changes in diatom assemblages, total organic carbon (TOC, total nitrogen (TN and biogenic silica (BSi and give an indication of nutrient in status and trends in Changjiang River estuary and its adjacent East China Sea. The diatom assemblages in the two cores generally increased gradually from the 1970s, and accelerated from the 1990s until now, reflecting the increased eutrophication and causing large algae blooms/red tides. The TOC, TN and BSi showing the similar trends, supported the interpretation of the eutrophication process indicated by diatom analyses. The two cores were located in different sea areas of the East China Sea, and we discuss their relative changes based on their environment characteristics. We also discuss the potential effect of anthropogenic influences and ongoing projects on eutrophication in the Changjiang River and its adjacent East China Sea.

  7. Nutrient dynamics from the Changjiang (Yangtze River) estuary to the East China Sea

    Science.gov (United States)

    Liu, Su Mei; Qi, Xiao Hong; Li, Xiaona; Ye, Hao Ran; Wu, Ying; Ren, Jing Ling; Zhang, Jing; Xu, Wei Yi

    2016-02-01

    Water and sediment samples were collected from the Changjiang (Yangtze River) estuary and the adjacent East China Sea during impoundment of the river at the Three Gorges Dam. The concentrations of dissolved inorganic and organic nutrients, and particulate inorganic phosphorus and particulate organic phosphorus in the water column (PIP and POP, respectively) and sediments (SIP and SOP, respectively) were analyzed. The nutrient dynamics in salt marshes associated with the Changjiang estuary were also considered. In addition, river water samples were collected bimonthly in the lower reaches of the Changjiang. The concentrations of dissolved inorganic nutrients, PIP and POP showed temporal and spatial variations, which decreased from the coast to offshore areas. The dissolved organic nitrogen and phosphorus (P) concentrations showed patchy distributions, but were consistent with the distribution of phytoplankton biomass. Phosphorus is the major limiting element for phytoplankton growth. Among the various P forms, particulate P represented 38-52% of total P. The PIP and POP concentrations showed clear seasonal variations corresponding to the occurrence of the levels of suspended particulate matter. The P accumulation rates showed a decreasing trend from the coast to offshore areas, and high P burial efficiencies were found; the latter were related to a low benthic PO43 - flux and high sediment accumulation rates. The potential bioavailable P was estimated to be 65-70% of total P, of which more than two-thirds was regenerated in the water column. The salt marsh in the Changjiang estuary plays an important ecological role in nutrient transport from the river to offshore areas, and increased P limitation.

  8. Sedimentation in the Three Gorges Dam and the future trend of Changjiang (Yangtze River sediment flux to the sea

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    Guogang Li

    2009-11-01

    Full Text Available The Three Gorges Dam (TGD on the upper Changjiang (Yangtze River, China, disrupts the continuity of Changjiang sediment delivery to downstream and coastal areas. In this study, which was based on 54 years of annual water and sediment data from the mainstream and major tributaries of Changjiang, sediment deposition induced by the TGD in 2003–2008 was quantified. Furthermore, we determined the theoretical trapping efficiency of the cascade reservoir upstream of the TGD. Its impact on Changjiang sediment flux in the coming decades is discussed. Results show that about 172 million tons (Mt of sediment was trapped annually by the TGD in 2003–2008, with an averaged trapping efficiency of 75%. Most of the total sediment deposition, as induced by the TGD (88%, accumulated within the region between the TGD site and Cuntan. However, significant siltation (12% of the total sediment deposition also occurred upstream of Cuntan as a consequence of the upstream extended backwater region of the TGD. Additionally, the Changjiang sediment flux entered a third downward step in 2001, prior to operation of the TGD. This mainly resulted from sediment reduction in the Jinshajiang tributary since the late 1990s. As the cascade reservoir is put into full operation, it could potentially trap 91% of the Jinshajiang sediment discharge and, therefore, the Jinshajiang sediment discharge would most likely further decrease to 14 Mt/yr in the coming decades. Consequently, the Changjiang sediment flux to the sea is expected to continuously decrease to below 90 Mt/yr in the near future, or only 18% of the amount observed in the 1950s. In the presence of low sediment discharge, profound impacts on the morphology of estuary, delta and coastal waters are expected.

  9. An Experimental Study on Major Element Release from the Sediments in the Changjiang (Yangtze River) Estuary

    Institute of Scientific and Technical Information of China (English)

    GUO Yanwei; YANG Shouye

    2015-01-01

    With the enhanced warming and acidification of global ocean, whether and to what extent the naturally-weathered fluvial sediment into the sea can release elements and thus influence the geochemical process and ecosystem of global ocean remain to be resolved. In this contribution, an experimental study was carried out to examine the release rates of major elements (Ca, K, Mg and Al) from the surface sediments in the Changjiang (Yangtze River) Estuary under the pH values of 4.0, 6.0 and 7.0. The two studied sediments consist primarily of quartz, plagioclase, calcite and clay minerals, with the BET (Brunauer, Emmett and Teller) surface areas of 61.7m2g-1 and 23.1m2g-1. Major elements of Ca, K, Mg and Al show different release rates under different solution pH values. With the decreasing solution pH, the release rates of Ca and K increase obviously, while the release rates of Mg and Al increase with the initial solution pH varying from 6.0 to 7.0. The different release rates of these elements are closely related to the original mineral composition of the sediments and the reaction kinetics. Based on the experimental observation, quartz and clay minerals that have low dissolution rates may dominate the major element release to the aqueous phase. This study reveals that the en-hancing ocean acidification could cause considerable release of major elements from natural terrigenous sediments into the ambient marine environment, which has to be considered carefully in the future study on global change.

  10. Nitrous oxide in the Changjiang (Yangtze River Estuary and its adjacent marine area: Riverine input, sediment release and atmospheric fluxes

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    G.-L. Zhang

    2010-11-01

    Full Text Available Dissolved nitrous oxide (N2O was measured in the waters of the Changjiang (Yangtze River Estuary and its adjacent marine area during five surveys covering the period of 2002–2006. Dissolved N2O concentrations ranged from 6.04 to 21.3 nM, and indicate great temporal and spatial variations. Distribution of N2O in the Changjiang Estuary was influenced by multiple factors and the key factor varied between cruises. Dissolved riverine N2O was observed monthly at station Xuliujing of the Changjiang, and ranged from 12.4 to 33.3 nM with an average of 19.4 ± 7.3 nM. N2O concentrations in the river waters showed obvious seasonal variations with higher values occurring in both summer and winter. Annual input of N2O from the Changjiang to the estuary was estimated to be 15.0 × 106 mol/yr. N2O emission rates from the sediments of the Changjiang Estuary in spring ranged from −1.88 to 2.02 μmol m−2 d−1, which suggests that sediment can act as either a source or a sink of N2O in the Changjiang Estuary. Average annual sea-to-air N2O fluxes from the studied area were estimated to be 7.7 ± 5.5, 15.1 ± 10.8 and 17.0 ± 12.6 μmol m−2d−1 using LM86, W92 and RC01 relationships, respectively. Hence the Changjiang Estuary and its adjacent marine area are a net source of atmospheric N2O.

  11. Three Gorges Dam alters the Changjiang (Yangtze) river water cycle in the dry seasons: Evidence from H-O isotopes.

    Science.gov (United States)

    Deng, Kai; Yang, Shouye; Lian, Ergang; Li, Chao; Yang, Chengfan; Wei, Hailun

    2016-08-15

    As the largest hydropower project in the world, the Three Gorges Dam (TGD) has attracted great concerns in terms of its impact on the Changjiang (Yangtze) River and coastal marine environments. In this study, we measured or collected the H-O isotopic data of river water, groundwater and precipitation in the mid-lower Changjiang catchment during the dry seasons of recent years. The aim was to investigate the changes of river water cycle in response to the impoundment of the TGD. Isotopic evidences suggested that the mid-lower Changjiang river water was ultimately derived from precipitation, but dominated by the mixing of different water masses with variable sources and isotopic signals as well. The isotopic parameter "deuterium excess" (d-excess) yielded large fluctuations along the mid-lower mainstream during the initial stage of the TGD impoundment, which was inherited from the upstream water with inhomogeneous isotopic signals. However, as the reservoir water level rising to the present stage, small variability of d-excess was observed along the mid-lower mainstream. This discrepancy could be explained that the TGD impoundment had significantly altered the water cycle downstream the dam, with the rising water level increasing the residence time and enhancing the mixing of reservoir water derived from upstream. This eventually resulted in the homogenization of reservoir water, and thus small fluctuations of d-excess downstream the dam after the quasi-normal stage (2008 to present). We infer that the retention effect of large reservoirs has greatly buffered the d-excess natural variability of water cycle in large river systems. Nevertheless, more research attention has to be paid to the damming effect on the water cycle in the river, estuarine and coastal areas, especially during the dry seasons. PMID:27096630

  12. Variations and net transport of dissolved inorganic nutrients in the South Passage of the Changjiang (Yangtze River) Estuary

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Dissolved inorganic nutrient elements were analyzed from the samples collected in the South Passage of the Changjiang (Yangtze River) Estuary in March 2003, including NH4+, NO3-, NO2- and PO43-. The water samples were collected with a Niskin sampler hourly at the near-surface, middle and near-bottom depths at the three stations-A1, A2 and A3-during two complete tidal cycles of neap tide and spring tide. Results showed that 1) the concentrations of NH4+, NO3- and NO2- were a little higher respectively during the neap tide than those during the spring tide, while PO43- showed an opposite trend, and each was higher in the ebb tide than in the flood tide, either for the neap tidal cycle or the spring tidal cycle; 2) higher stratification of the nutrients existed obviously in this area, with the concentrations of which increased from the bottom to the surface, especially for NH4+ and NO3-; 3) the coefficient of variation (C.V.) values of all dissolved inorganic nutrients varied from 4.06% to 36.8% beyond different influences of the tidal current and Changjiang runoff; 4) with increasing suspended matter in the water column, the concentrations of PO43- became lower in the filtered water; and 5) the total transport of each tidal cycle was much more in the spring tide than in the neap tide, and the positive values indicated that the nutrients had been exported to the East China Sea. Studies on the variations and net transport of dissolved inorganic nutrients in the South Passage of the Changjiang Estuary will provide the scientific basis for the study of the mechanism of red tide in the East China Sea.

  13. Detection of the Three Gorges Dam influence on the Changjiang (Yangtze River) submerged delta

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    Dai, Zhijun; Liu, James T.; Wei, Wen; Chen, Jiyu

    2014-10-01

    While most large river-deltas in the world are facing the risk of subsidence and erosion in the Anthropocene, it is suspected that the Changjiang submerged delta (CSD) could be subjected to the impacts of the world's largest dam, the Three Gorges Dam (TGD). Here we firstly indicate that the CSD went through high accumulation (1958-1978) slight accumulation (1978-1997), slight erosion (1997-2002) and high accumulation (2002-2009), despite the 70% reduction of the sediment load from upstream since the operation of the TGD in 2003. Meanwhile, at the depocenter of the submerged delta, the accumulation maintained a high rate of 10 cm/yr during 1958-2009. This suggests on a longer term, the distal sediment source from the upstream had little effect on the CSD. Within this time frame the changes in the partition of sediment load among the branching channels of the Changjiang Estuary could likely control the shifting of the depocenter of the CSD on a decadal time scale. Episodic extreme floods and storm surges also increased the magnitude of deposition and erosion of the CSD on short-term scales. A re-evaluation of the impacts of TGD on the CSD is urgently needed.

  14. Decline in suspended sediment concentration delivered by the Changjiang (Yangtze) River into the East China Sea between 1956 and 2013

    Science.gov (United States)

    Dai, Zhijun; Fagherazzi, Sergio; Mei, Xuefei; Gao, Jinjuan

    2016-09-01

    The temporal evolution of suspended sediment concentration (SSC) in a river debouching into the ocean provides vital insights into erosion processes in the watershed and dictates the evolution of the inner continental shelf. While the delivery of sediment from rivers to the ocean has received special attention in the recent past, few studies focused on the variability and dynamics of river SSC, especially in the Changjiang (Yangtze) river, China, the longest river in Asia. Here, variations in SSC delivered by the Changjiang River to the East China Sea and possible causes of its variability were detected based on a long-term time series of daily SSC and monthly water discharge measured at the Datong gauging station. The SSC data are further compared to a hydrological analysis of yearly precipitation covering the entire catchment. The results indicate the presence of a decline in SSC in the period 1956-2013, which can be divided into three phases: (i) high SSC (0.69 kg/m3) in the wet season and low SSC (0.2 kg/m3) in the dry season from 1956 to 1970; (ii) relative high SSC (0.58 kg/m3) in the wet season and low SSC (0.15 kg/m3) in the dry season from 1971 to 2002; and (iii) low SSC (0.19 kg/m3) in the wet season and very low SSC (0.09 kg/m3) in the dry season after 2002. These three periods have a mean yearly SSC values of 0.62, 0.42, and 0.18 kg/m3, respectively. Compared with 1956-1970, the slope of the rating curve between SSC and water discharge decreased, respectively, by 2% and 30% during the period 1971-2002 and 2002-2013. Soil erosion, dam construction, and banks reinforcement along the Changjiang River are the main causes of SSC variations. Fluctuations in water discharge are also controlling the SSC long-term variations. Specifically, from 1956 to 1970, the effect of soil erosion overrules that of dam impoundment, which is likely responsible for the high SSC; during the period 1970-2002, the influence of dam impoundment increases while that of soil erosion

  15. Simulated circulations off the Changjiang (Yangtze) River mouth in spring and autumn

    Institute of Scientific and Technical Information of China (English)

    朱建荣; 戚定满; 肖成猷

    2004-01-01

    The circulations off the Changjiang mouth in May and November were simulated by a three dimension numerical model with monthly averaged parameters of dynamic factors in this paper. The area covers the East China Sea (ECS), Yellow Sea and Bohai Sea. Simulated results show that the circulation off the Changjiang mouth in spring and autumn is mainly the Changjiang runoff and Taiwan Warm Current (TWC). The Changjiang discharge is much larger in May than in November, and the wind is westward in May, and southward in November off the Changjiang mouth. The runoff in May branches in three parts, one eastward flows, the other two flow northward and southward along the Subei and Zhejiang coast respectively. The Changjiang diluted water expands eastward off the mouth, and forms a strong salinity front near the mouth. Surface circulation in autumn is similar to that in winter, the runoff southward flows along the coast, and the northward flowing TWC becomes weaker compared to that in spring and summer. The bottom circulations in May and November are mainly the runoffnear the mouth and the TWC offthe mouth, and the runoff and TWC are greater in May than in November.

  16. Sinking rates of phytoplankton in the Changjiang (Yangtze River) estuary: A comparative study between Prorocentrum dentatum and Skeletonema dorhnii bloom

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    Guo, Shujin; Sun, Jun; Zhao, Qibiao; Feng, Yuanyuan; Huang, Daji; Liu, Sumei

    2016-02-01

    Sinking rates of phytoplankton community with variable taxonomic composition in the offshore Changjiang (Yangtze River) estuary were measured during two cruises in spring and summer, 2011. A homogenous-sample method SETCOL was used to determine the sinking rates. Phytoplankton community was dominated by dinoflagellates in spring and diatoms in summer, and two species Prorocentrum dentatum and Skeletonema dorhnii formed algal blooms in the survey area during the two cruises, respectively. Phytoplankton sinking rates ranged from 0.13 to 1.04 m day- 1 (average = 0.61 ± 0.24 m day- 1) in spring and 0.28 to 1.71 m day- 1 (average = 0.80 ± 0.34 m day- 1) in summer. In the surface layer, phytoplankton sinking rates at the P. dentatum bloom stations in spring were lower than that at the S. dorhnii bloom stations in summer. No significant correlation was found between phytoplankton sinking rates and most of the environmental parameters during the two cruises, except for temperature and nitrite concentration in summer. A significant correlation was observed between phytoplankton sinking rates and phytoplankton community structure in the surface layers: the higher dominance of diatom in the phytoplankton community corresponded to higher phytoplankton sinking rate. Therefore, the phytoplankton community structure other than the environmental parameters, is the important factor to affect the sinking rates greatly. The consequent carbon flux caused by phytoplankton sinking was estimated, and results suggested that the carbon flux to bottom water during the S. dorhnii bloom (average = 63.13 ± 48.16 mg C m- 2 day- 1) in summer was about 2.4 fold of that during the P. dentatum bloom (average = 26.10 ± 26.25 mg C m- 2 day- 1) in spring. These findings provide us some insight in understanding the carbon export contributed by marine phytoplankton in the coastal sea, where frequent phytoplankton blooms and high following carbon export occur.

  17. Erosion patterns in the Changjiang (Yangtze River) catchment revealed by bulk-sample versus single-mineral provenance budgets

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    Vezzoli, Giovanni; Garzanti, Eduardo; Limonta, Mara; Andò, Sergio; Yang, Shouye

    2016-05-01

    The Changjiang, the fourth longest river on Earth and the largest in Eurasia, has a complex sediment-routing system presently interrupted by the Three Gorges Dam, the world's largest hydroelectric engineering project. To study sediment-generation processes in the huge catchment and compare the different erosion patterns obtained by different methodological approaches, high-resolution petrographic and heavy-mineral analyses were performed on sands from the trunk river and its major tributaries. The frequency distributions of diverse groups of detrital amphiboles were also investigated. Rigorous statistical methods were used to define end-members, evaluate mineralogical variability, assess similarities among samples, and eventually calculate the relative contributions from each major tributary to the trunk river by forward end-member modelling of integrated compositional data. The litho-quartzose sand with few heavy minerals generated in Tibetan headwaters evolves downstream to feldspatho-litho-quartzose with medium-rank metamorphic rock fragments and moderately rich amphibole-epidote suites. Sand across the Sichuan basin and as far as the Three Gorges Dam is enriched in mafic volcanic, clinopyroxene, and carbonate grains eroded from Permian basalts and Paleozoic strata of the South China Block. The final (Yangtze) tract is characterized by litho-feldspatho-quartzose sand with moderately poor, amphibole-dominated suites with epidote, clinopyroxene, and garnet. The orogenic compositional signature acquired in the upper part of the basin is thus carried all the way to the Chinese passive margin, as observed also for the Yellow River in the north. Even after long-distance transport across wide continental areas, detrital modes thus reveal the tectonic character of the source rather than the geodynamic environment of the sink. Quantitative provenance analysis indicates that left-bank tributaries draining the Longmen and Qinlin mountains supply most of the sand reaching

  18. Hydrocarbons in surface sediments from the Changjiang (Yangtze River) estuary, East China Sea

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    Bouloubassi, Ioanna; Fillaux, Joelle; Saliot, Alain [Universite Pierre et Marie Curie, Lab. de Biogeochimie et Chimie Marines, Paris, 75 (France)

    2001-07-01

    Sedimentary aliphatic (AH) and polycyclic aromatic hydrocarbons (PAHs) were studied in the Changjiang Estuary and the adjacent East China Sea. Total AH ranged from 2.20 to 11.82 {mu}g g {sup -1} and consisted of n-alkanes and a dominant petroleum-related unresolved complex mixture (UCM). Within the n-alkanes, terrestrial plant wax compounds prevailed at nearly all stations. Of the PAHs, biogenic perylene dominated at stations receiving riverine inputs. Anthropogenic PAHs originating from combustion/pyrolysis processes varied from 17 to 157 ng g {sup -1}, while fossil PAH concentrations ranged from 42 to 187 ng g {sup -1}. Both biogenic and anthropogenic hydrocarbons are primarily derived from riverine discharges and accumulate at shallow-water stations. Distinct phase associations lead, nevertheless, to different sedimentation patterns. Fossil PAHs are enhanced at offshore stations where they are introduced directly by shipping activities. Biomarker fingerprints ascribe their source to Chinese crude oils. The overall levels of anthropogenic hydrocarbons are low compared to relevant areas worldwide and reveal a low/moderate level of hydrocarbon pollution. (Author)

  19. Meiofauna distributions at the oxygen minimum zone in Changjiang (Yangtze) River Estuary waters

    Institute of Scientific and Technical Information of China (English)

    HUA Er; ZHANG Zhinan; ZHANG Yan

    2006-01-01

    A quantitative study on meiofauna was carried out along a transect throughout the Changjiang Estuary's oxygen minimum zone (OMZ) in the East China Sea. There exist two distinct station groups in the OMZ: the fine-grained hypoxic area and the more fine-grained anoxic area. Meiofauna abundance ranged from (101.5±31.0) ind./cm2 (hypoxic area) to (369.9±123.9) ind./cm2 (anoxic area) along the transect. Free-living marine nematodes were the numerically dominant meiofauna at every station. The anoxic area differed significantly in meiofauna abundance and vertical distribution pattern from the hypoxic area. Within the anoxic area, nematodes abundance increased and amounted to over 90% of the total meiofauna; about 50% of nematodes were found in the 2~5 and 5~8 cm layers. At hypoxic stations, about over 85% were restricted to the top 2 cm. Benthic copepod abundance and dominance decreased consistently with the oxygen gradient. The pattern of meiofauna biomass was similar to that of abundance. The correlation analysis of the meiofauna numbers and environmental parameters indicated that abundance and biomass of total meiofauna and nematodes had significant or highly significant (P<0.05 or P<0.01) correlations with Chl a and Pha a, but no significant (P>0.05) correlations with bottom-water oxygen (BWO2). On the other hand, there was a highly significant positive correlation between benthic copepod abundance and bottom-water oxygen (P<0.05). The investigation on the nematode community structure indicated that two different nematode communities existed in hypoxic and anoxic areas. In certain way, the shift in nematode species composition distinguishes the anoxia to hypoxia. Nematode diversity was generally lower within the anoxic stations than the hypoxic ones, but the difference was not significant. Indices of the nematode community structure varied in relation to the bottom-water oxygen together with bottom-water temperature, Chl a concentration and median grain

  20. Coupling the chemical dynamics of carbonate and dissolved inorganic nitrogen systems in the eutrophic and turbid inner Changjiang (Yangtze River) Estuary

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    Zhai, W.-D.; Yan, X.-L.

    2015-04-01

    To better understand biogeochemical processes controlling CO2 dynamics in those eutrophic large-river estuaries and coastal lagoons, we investigated surface water carbonate system, nutrients, and relevant hydrochemical parameters in the inner Changjiang (Yangtze River) Estuary, covering its channel-like South Branch and the lagoon-like North Branch, shortly after a spring-tide period in April 2010. In the North Branch, with a water residence time of more than 2 months, biogeochemical additions of ammonium (7.4 to 65.7 μmol kg-1) and alkalinity (196 to 695 μmol kg-1) were detected along with high salinity of 4.5 to 17.4. In the South Branch upper-reach, unusual salinity values of 0.20 to 0.67 were detected, indicating spillover waters from the North Branch. The spillover waters enhanced the springtime Changjiang export fluxes of nutrients, dissolved inorganic carbon, and alkalinity. And they affected the biogeochemistry in the South Branch, by lowering water-to-air CO2 flux and continuing the nitrification reaction. In the North Branch, pCO2 was measured from 930 to 1518 μatm at the salinity range between 8 and 16, which was substantially higher than the South Branch pCO2 of 700 to 1100 μatm. Based on field data analyses and simplified stoichiometric equations, we suggest that the North Branch CO2 productions were quantified by biogeochemical processes combining organic matter decomposition, nitrification, CaCO3 dissolution, and acid-base reactions in the estuarine mixing zone. Although our study is subject to limited temporal and spatial coverage of sampling, we have demonstrated a procedure to quantificationally constrain net CO2 productions in eutrophic estuaries and/or coastal lagoons, by coupling the chemical dynamics of carbonate and dissolved inorganic nitrogen systems.

  1. Coupling the chemical dynamics of carbonate and dissolved inorganic nitrogen systems in the eutrophic and turbid inner Changjiang (Yangtze River Estuary

    Directory of Open Access Journals (Sweden)

    W.-D. Zhai

    2015-04-01

    Full Text Available To better understand biogeochemical processes controlling CO2 dynamics in those eutrophic large-river estuaries and coastal lagoons, we investigated surface water carbonate system, nutrients, and relevant hydrochemical parameters in the inner Changjiang (Yangtze River Estuary, covering its channel-like South Branch and the lagoon-like North Branch, shortly after a spring-tide period in April 2010. In the North Branch, with a water residence time of more than 2 months, biogeochemical additions of ammonium (7.4 to 65.7 μmol kg−1 and alkalinity (196 to 695 μmol kg−1 were detected along with high salinity of 4.5 to 17.4. In the South Branch upper-reach, unusual salinity values of 0.20 to 0.67 were detected, indicating spillover waters from the North Branch. The spillover waters enhanced the springtime Changjiang export fluxes of nutrients, dissolved inorganic carbon, and alkalinity. And they affected the biogeochemistry in the South Branch, by lowering water-to-air CO2 flux and continuing the nitrification reaction. In the North Branch, pCO2 was measured from 930 to 1518 μatm at the salinity range between 8 and 16, which was substantially higher than the South Branch pCO2 of 700 to 1100 μatm. Based on field data analyses and simplified stoichiometric equations, we suggest that the North Branch CO2 productions were quantified by biogeochemical processes combining organic matter decomposition, nitrification, CaCO3 dissolution, and acid-base reactions in the estuarine mixing zone. Although our study is subject to limited temporal and spatial coverage of sampling, we have demonstrated a procedure to quantificationally constrain net CO2 productions in eutrophic estuaries and/or coastal lagoons, by coupling the chemical dynamics of carbonate and dissolved inorganic nitrogen systems.

  2. Spatial distribution and diurnal variation of chemical oxygen demand at the beginning of the rainy season in the Changjiang (Yangtze) River Estuary

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A field observation was carried out in the Changjiang (Yangtze) River Estuary from May 19 to 26, 2003. A total of 29 stations, including 2 anchored stations, were occupied through almost the whole salinity gradient. Based on the observation data, biogeochemistry of chemical oxygen demand (COD) was examined. Spatial distribution pattern of COD shows that it decreased downstream. The COD concentration varied generally within a narrow range of 1.24-1.60 mg/L in the zone around the river mouth, beyond which it decreased rapidly to 0.20 mg/L. In the mixed water zone, the fluctuation in COD was smaller at 2 m above the bottom layer than at the surface layer in 48 h. In the seawater zone, the 48-h fluctuation at the surface was the largest, followed by that of 5 m below the surface and 2 m above the bottom layers in a range of from 2.50 to 0.55 mg/L. Freshwater discharge was the dominant source of COD in the estuary. The average COD beyond the river mouth was 2.7 rog/L, which accorded with the Chinese seawater quality Grade I. Relationships between dissolved oxygen and biogeochemical parameters such as suspended particulate matter, dissolved organic matter and chlorophyll-a were also discussed.

  3. Macrobenthic assemblages of the Changjiang River estuary (Yangtze River, China) and adjacent continental shelf relative to mild summer hypoxia

    Science.gov (United States)

    Liao, Yibo; Shou, Lu; Tang, Yanbin; Zeng, Jiangning; Gao, Aigen; Chen, Quanzhen; Yan, Xiaojun

    2016-06-01

    To assess the effects of hypoxia, macrobenthic communities along an estuarine gradient of the Changjiang estuary and adjacent continental shelf were analyzed. This revealed spatial variations in the communities and relationships with environmental variables during periods of reduced dissolved oxygen (DO) concentration in summer. Statistical analyses revealed significant differences in macrobenthic community composition among the three zones: estuarine zone (EZ), mildly hypoxic zone (MHZ) in the continental shelf, and normoxic zone (NZ) in the continental shelf (Global R =0.206, P =0.002). Pairwise tests showed that the macrobenthic community composition of the EZ was significantly different from the MHZ (pairwise test R =0.305, P =0.001) and the NZ (pairwise test R =0.259, P =0.001). There was no significant difference in macrobenthic communities between the MHZ and the NZ (pairwise test R =0.062, P =0.114). The taxa included small and typically opportunistic polychaetes, which made the greatest contribution to the dissimilarity between the zones. The effects of mild hypoxia on the macrobenthic communities are a result not only of reduced DO concentration but also of differences in environmental variables such as temperature, salinity, and nutrient concentrations caused by stratification.

  4. Changes in nutrient uptake of phytoplankton under the interaction between sunlight and phosphate in the Changjiang(Yangtze)River Estuary

    Institute of Scientific and Technical Information of China (English)

    FANG Tao; LI Daoji; YU Lihua; LI Yun

    2008-01-01

    We conducted ship-board incubation experiments to investigate changes in nutrient uptake of phytoplankton under different phosphate concentrations and irradiances in the Changjiang River Estuary and its adjacent waters in China.Under 100% natural irradiance the uptake rates of phosphate,silicate,and nitrate were accelerated at high phosphate levels(1.84 μM),while under low irradiance(about 50%natural irradiance)their uptake rates were restrained at the high but stimulated greatly at the intermediate phosphate concentrations(1.26μM),as the growth of phytoplankton,changes in nitrite and ammonium uptake didn't follow an obvious pattern.Our results alSO showed that there were linear relationships between nitrate,silicate and phosphate uptake at different phosphate concentrations under low and high irradiances,and the growth period of phytuplankton was prolonged both at the high phosphate concentrations under high irradiance and at the intermediate concentrations under low irradiance,suggesting that the limitation of phytoplankton growth mainly reflected changes in its growth period,and because no such environment(low-irradiance and low phosphate concentrations)actually existed in a high turbidity zone,phytoplankton blooms hardly occurred there.In the absence of irradiance,denitrification occurred readily and phytoplankton was kept decreasing,which resulted in phOSphate regeneratton.

  5. Vegetation and climate changes in the Changjiang (Yangtze River) Delta, China, during the past 13,000 years inferred from pollen records

    Science.gov (United States)

    Yi, Sangheon; Saito, Yoshiki; Zhao, Quanhong; Wang, Pinxian

    2003-06-01

    A high-resolution pollen record from 2 boreholes from the Changjiang (Yangtze River) delta shows a series of well-defined changes in vegetation and climate over the last 13,000 yr. In latest Pleistocene to early Holocene time (12,900- 10,300 cal yr BP), pollen dominated by the xerophytic herb Artemisia and common conifers indicate coniferous forest and grasslands and a cool, dry climates, possibly represented by the Younger Dryas. From 10,300 to 9000 cal yr BP, a warm, wet climate fostered the development of mixed broadleaved evergreen-deciduous forests to grow on the grasslands and surrounding hills and uplands. From 9000 to 7600 cal yr BP, the dominance of conifers and the reduction in broadleaved evergreen trees pollen suggest cool, dry conditions. The mid-Holocene "hypsithermal" (7600- 4800 cal yr BP) is represented by a large expansion of subtropical evergreen-deciduous broadleaved forests. Between 4800 and 1300 cal yr BP, which corresponds to a Neoglacial period elsewhere, conifers are dominant, along with common herbs, whereas the area with broadleaved evergreen trees shrink under the cool, dry conditions. The first occurrence of Fagopyrum pollen at 4500 cal yr BP suggests human influence. The significant change in arboreal and herbaceous pollen after 1300 cal yr BP reflects widespread intensive human influence.

  6. Size-fractionated phytoplankton biomass in autumn of the Changjiang (Yangtze) River Estuary and its adjacent waters after the Three Gorges Dam construction

    Science.gov (United States)

    Song, Shuqun; Sun, Jun; Luan, Qingshan; Shen, Zhiliang

    2008-08-01

    A cruise was undertaken from 3rd to 8th November 2004 in Changjiang (Yangtze) River Estuary and its adjacent waters to investigate the spatial biomass distribution and size composition of phytoplankton. Chlorophyll- a (Chl- a) concentration ranged 0.42-1.17 μg L-1 and 0.41-10.43 μg L-1 inside and outside the river mouth, with the mean value 0.73 μg L-1 and 1.86 μg L-1, respectively. Compared with the Chl- a concentration in summer of 2004, the mean value was much lower inside, and a little higher outside the river mouth. The maximal Chl- a was 10.43 μg L-1 at station 18 (122.67°E, 31.25°N), and the region of high Chl- a concentration was observed in the central survey area between 122.5°E and 123.0°E. In the stations located east of 122.5°E, Chl- a concentration was generally high in the upper layers above 5 m due to water stratification. In the survey area, the average Chl- a in sizes of >20 μm and Skeletonema costatum, Prorocentrum micans and Scrippsiella trochoidea were the dominant species in surface water. The spatial distribution of cell abundance of phytoplankton was patchy and did not agree well with that of Chl- a, as the cell abundance could not distinguish the differences in shape and size of phytoplankton cells. Nitrate and silicate behaved conservatively, but the former could probably be the limitation factor to algal biomass at offshore stations. The distribution of phosphate scattered considerably, and its relation to the phytoplankton biomass was complicated.

  7. GLOBAL CHARM OF THE CHANGJIANG RIVER DELTA

    Institute of Scientific and Technical Information of China (English)

    CHEN Shu-peng; ZHOU Cheng-hu; CHEN Qiu-xiao

    2003-01-01

    Based on the theory of geo-economy, under the new situation of global economy, information network and China's entry into WTO, also with the holding of APEC (in 2001) and the International Exposition in the near future, the Changjiang (Yangtze) River Delta is striding toward the spectacular international multi-polar situation and becomes one of core regions with high-speed development. Facing the ocean and world all along, leading the progressive tides of the age and scintillating the splendor of the nation, she does advance with time. Through a long period of irrigation projects construction and intensive operation of lands in previous agricultural society, the artificial wetland ecosystem with a positive cycle had ever been formed in this region. At present, environmental pollution and urban expansion resulted from post-industrialization are being rectified. The delta will be the paradigm of industrial and agricultural modernization along the sustainable development road. With the rapid development of urbanization,she has been one of the regions with the highest density population and high urbanization level. Taking the Changjiang River estuary and the Hangzhou Bay as two parts, she is continuously strengthening and adjusting her interiorstructure, expanding mothball space and constructing the oriental modern "logistics center" to link the whole world. The butterfly-style urban system of the Changjiang River Delta is flying, probably engendering earthshaking "butterfly effect".

  8. Isotopic composition of dissolved boron and its geochemical behavior in a freshwater-seawater mixture at the estuary of the Changjiang (Yangtze) River

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The isotopic composition of dissolved boron, in combination with the elemental concentrations of B, Cl and salinities in freshwater-seawater mixed samples taken from the estuary of the Changjiang River, the largest one in China, was investigated in detail in this study. Brackish water and seawater samples from the estuary of the Changjiang River were collected during low water season in November, 1998. Boron isotopic compositions were determined by the Cs2BO2+-graphite technique with a analytical uncertainty of 0.2‰ for NIST SRM 951 and an average analytical uncertainty of 0.8‰ for the samples. The isotopic compositions of boron, expressed in δ11B, and boron concentrations in the Changjiang River at Nanjing and seawater from the open marine East Sea, China, are characterized by δ11B values of -5.4‰ and 40.0‰, as well as 0.0272 and 4.43 mg B/L, respectively. Well-defined correlations between δ11B values, B concentrations and Cl concentrations are interpreted in terms of binary mixing between river input water and East Sea seawater by a process of straightforward dilution. The offsets of δ11B values are not related to the contents of clastic sediment and to the addition of boron. These relationships favor a conservative behavior of boron at the estuarine of the Changjiang River.

  9. Sedimentation in the Three Gorges Dam and its impact on the sediment flux from the Changjiang (Yangtze River, China

    Directory of Open Access Journals (Sweden)

    B. Q. Hu

    2009-07-01

    Full Text Available After the operation of the Three Gorges Dam (TGD in 2003, the mean annual sediment load at Yichang station, 44 km downstream of the TGD, decreased drastically by 84% of that in the pre-TGD period (1986–2002. Annually, about 162 million tons (Mt sediment was trapped by the TGD in 2003–2007, of which 92% was deposited within the region from Cuntan to TGD site; the remaining 8% deposited in the upstream of Cuntan owing to the effect of the extended backwater region of TGD. The theoretical trapping efficiency of the cascade reservoir on the lower Jinshajiang was calculated and its impact on the Changjiang sediment in the coming decades discussed. The results show that the cascade reservoir will trap up to 91% of the sediment discharge coming from the Jinshajiang tributary, and then the sediment discharge from the Changjiang to the sea will continuously decrease to less than 90 Mt/yr in the coming decades. In the presence of low sediment discharge, profound impacts on the morphology of estuary, delta and coastal sea are expected.

  10. Size-fractionated phytoplankton biomass in autumn of the Changjiang (Yangtze) River Estuary and its adjacent waters after the Three Gorges Dam construction

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A cruise was undertaken from 3rd to 8th November 2004 in Changjiang (Yangtze) River Estuary and its adjacent waters to investigate the spatial biomass distribution and size composition of phytoplankton. Chlorophyll-a (Chl-a) concentration ranged 0.42-1.17 μg L-1 and 0.41-10.43 μg L-1 inside and outside the river mouth, with the mean value 0.73 μg L-1 and 1.86 μg L-1, respectively. Compared with the Chl-a concentration in summer of 2004, the mean value was much lower inside, and a little higher outside the river mouth. The maximal Chl-a was 10.43 μg L-1 at station 18 (122.67(E, 31.25(N), and the region of high Chl-a concentration was observed in the central survey area between 122.5(E and 123.0(E. In the stations located east of 122.5(E, Chl-a concentration was generally high in the upper layers above 5 m due to water stratification. In the survey area, the average Chl-a in sizes of >20 μm and <20 μm was 0.28 μg L-1 and 1.40 μg L-1, respectively. High Chl-a concentration of <20 μm size-fraction indicated that the nanophytoplankton and picophytoplankton contributed the most to the biomass of phytoplankton. Skeletonema costatum, Prorocentrum micans and Scrippsiella trochoidea were the dominant species in surface water. The spatial distribution of cell abundance of phytoplankton was patchy and did not agree well with that of Chl-a, as the cell abundance could not distinguish the differences in shape and size of phytoplankton cells. Nitrate and silicate behaved conservatively, but the former could probably be the limitation factor to algal biomass at offshore stations. The distribution of phosphate scattered considerably, and its relation to the phytoplankton biomass was complicated.

  11. Analyses of intermittent mixing and stratification within the North Passage of the Changjiang (Yangtze) River estuary, China: A three-dimensional model study

    Science.gov (United States)

    Pu, Xiang; Shi, John Z.; Hu, Guo-Dong

    2016-06-01

    The TELEMAC-3D, incorporating a stability function, and the potential energy anomaly equation (ϕ-equation), are used to analyze neap-spring tidal and intratidal variability of intermittent mixing and stratification within the North Passage of the Changjiang (Yangtze) River estuary in the wet season. Eight terms in the ϕ-equation are used to examine physical mechanisms and the relative importance of each term for the lower reach of the North Passage. As revealed by the gradient Richardson number (Ri), the Simpson number (Si) and the potential energy anomaly (ϕ), weak mixing and persistent stratification appear on a neap tide, while strong mixing and periodic stratification on a spring tide within the main channel in the middle and lower reaches of the North Passage. The landward subtidal flow is much stronger on a neap tide than that on a spring tide. Within the main channel in the lower reach, large magnitude of longitudinal ϕ-advection (Au) reflects the important effect of saltwedge movement on stratification. Large magnitude of lateral ϕ-advection (Av) may be enhanced by large lateral gradient of ϕ due to the complex bathymetry and artificial structures. Both longitudinal (Au) and lateral ϕ-advections (Av) are temporally and spatially intermittent. Large longitudinal depth-mean straining (Bu) overlays the combined effect of tidal straining, circulation and river discharge. Large lateral depth-mean straining (Bv) is generated by large lateral density gradient interacting with the shear flow. The magnitude of integrated vertical turbulent buoyancy flux (E) mainly depends on tidal stirring at the bottom, while wind stirring at the surface and shear instability at the pycnocline are secondary contributors. The magnitudes of the other physical mechanisms including longitudinal non-mean straining (Cu), lateral non-mean straining (Cv) and vertical advection (D) are relatively smaller than those above. Neap-spring tidal variability of mixing and stratification

  12. Study on the total water pollutant load allocation in the Changjiang (Yangtze River) Estuary and adjacent seawater area

    Science.gov (United States)

    Deng, Yixiang; Zheng, Binghui; Fu, Guo; Lei, Kun; Li, Zicheng

    2010-02-01

    With the rapid economic development, the water quality is worsening and red tide takes place frequently in the Changjiang Estuary and adjacent seawaters. To improve the marine water quality, the total inland pollutant load should be controlled effectively. With efficiency and fairness in consideration, the total maximum allowable loads of COD Mn, NH 3-N, inorganic nitrogen and active phosphate to the seawaters were calculated and allocated by the linear programming method based on the water quality response fields of the pollution sources. The maximum allowable loads are 2008 × 10 3 tons, 169 × 10 3 tons, 226 × 10 3 tons and 18 × 10 3 tons for COD Mn, NH 3-N, inorganic nitrogen and active phosphate when the water quality targets are requested to be achieved in the whole studied region, and 346 × 10 3 tons and 32 × 10 3 tons for inorganic nitrogen and active phosphate when the water quality targets to be achieved only in the red tide sensitive area. The cut task of COD Mn and NH 3-N is relatively easy and can be finished by the watershed environmental plan; while the cut task of inorganic nitrogen and active phosphate is tremendous. The coastal provinces should install more denitrification and dephosphorization facilities in the existing waste water treatment plants or build new ones to control the red tides in the concerned seawaters.

  13. Nitrogen budget in the Changjiang River drainage area

    Institute of Scientific and Technical Information of China (English)

    JIANG Tao; YU Zhiming; SONG Xiuxian; CAO Xihua

    2012-01-01

    We established a budget model of nitrogen (N) inputs and outputs between watersheds and waterbodies to determine the sources of riverine N in the Changjiang (Yangtze) River drainage area.Nitrogen inputs in the budget included N from synthetic fertilizer,biological fixation by leguminous and other crops,wet/dry atmospheric deposition,excreta from humans and animals,and crop residues.The total N input was estimated to be 17.6 Tg,of which 20% or 3.5 Tg N was transported into waterbodies.Of the total N transported into waterbodies,the largest proportion was N from animal waste (26%),followed by N from atmospheric wet/dry deposition (25%),synthetic fertilizer N (17%),N in sewage wastes (17%),N in human waste from rural areas (6%) and industrial wastewater N (9%).We studied the spatial patterns of N inputs and outputs by dividing the Changjiang River drainage area into four sub-basins,from upstream to downstream:the Tongtian River drainage area (TTD,the headwater drainage area,138 000 km2,less disturbed by human activities); the Jinsha River drainage area (JSD,347 000 km2,less disturbed by human activities,approx.3 500 km upstream of the Changjiang estuary); the Pingshan-Yichang drainage area (PYD,520 500 km2,large-scale human disturbance,about 2 000 km upstream of the Changjiang estuary);and the Yichang-Datong drainage area (YDD,699 900 km2,large-scale human disturbance,approx.620 km upstream of the Changjiang estuary).The average N input into waterbodies was 2.3,7.3,24.1,and 28.2 kg N/ha in the TTD,JSD,PYD,and YDD sub-basins,respectively,suggesting an increase of N-components of more than 10 times from upstream to downstream areas.

  14. Temporal variability of particulate organic carbon in the lower Changjiang (Yangtze River) in the post-Three Gorges Dam period: Links to anthropogenic and climate impacts

    Science.gov (United States)

    Wu, Ying; Bao, Hongyan; Yu, Hao; Zhang, Jing; Kattner, Gerhard

    2015-11-01

    Suspended particles from the lower Changjiang were collected monthly from 2003 to 2011, which corresponds to the three construction periods of the Three Gorges Dam. Organic carbon (%OC), organic carbon to total nitrogen molar ratio, stable carbon isotope, and terrestrial biomarkers were examined. Rating curve studies were applied for the temporal trend analysis. The composition of particulate lignin phenols exhibited clear annual and periodic variations but only minor seasonal changes. Lignin phenol ratios (vanillyl/syringyl and cinnamyl/vanillyl) indicated that the terrigenous organic matter (OM) was primarily composed of woody and nonwoody tissue derived from angiosperm plants. The low-lignin phenol yields (Λ8) in combination with higher acid to aldehyde ratios reflected a substantial contribution from soil OM to the particle samples or modifications during river transport. The temporal shift of the lignin phenol vegetation index with the sediment load during the flood seasons revealed particulate organic matter (POM) erosion from soils and the impact of hydrodynamic processes. The dam operations affected the seasonal variability of terrigenous OM fluxes, although the covariation of lignin and sediment loads with discharged water implies that unseasonal extreme conditions and climate change most likely had larger influences, because decreases in the sediment load and lignin flux alter the structure and composition of particulate OM (POM) on interannual time scales, indicating that they may be driven by climate variability. The modification of the composition and structure of POM will have significant impacts on regional carbon cycles and marine ecosystems.

  15. The black water around the Changjiang (Yangtze) Estuary in the spring of 2003

    Institute of Scientific and Technical Information of China (English)

    BAI Yan; HE Xianqiang; PAN Delu; ZHU Qiankun; GONG Fang

    2009-01-01

    The Changjiang (Yangtze) Estuary is located in the East China Sea shelf with shallow water. Affected by the tide mixing and the runoff of the Changjiang River and the Qiantang River, the turbidity is very high. Generally, the water-leaving radiance is high in the turbid water because of the large particle scattering. Based on the in-situ data and ocean color remote sensing data of SeaWiFS, it was found that there was a black water region with the normalized water-leaving radiances less than 0.5 mW/(cm~2μm~2·sr). The optical principle of the occurrence of this black water was analyzed by the inherent optical properties and the ocean color components. The results show that black water is caused by the relative low values of the suspended particle matter concentration and the back scattering ratio. In the black water region, the percentage of the phytoplankton absorption was relatively high, and the large size of the phytoplankton caused the low value of the particle backscattering ratio.

  16. Satellite estimates of wide-range suspended sediment concentrations in Changjiang (Yangtze) estuary using MERIS data

    NARCIS (Netherlands)

    Shen, F.; Verhoef, W.; Zhou, Y.; Salama, M.S.; Liu, X.

    2010-01-01

    The Changjiang (Yangtze) estuarine and coastal waters are characterized by suspended sediments over a wide range of concentrations from 20 to 2,500 mg l-1. Suspended sediment plays important roles in the estuarine and coastal system and environment. Previous algorithms for satellite estimates of sus

  17. FUZZY COMPREHENSIVE EVALUATION OF CONTAINER TRANSPORTATION MODES ALONG THE CHANGJIANG RIVER MAIN LINE AND ITS DELTA AREA

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shi-yu; XIAO Han-liang

    2003-01-01

    The Changjiang River (Yangtze) is one of the fastest growth areas of container transportation in Chi-na. Rail, road and water transportation have competed against each other for container transportation in the Chang-jiang River main line and its delta area. It is of significance to assess these different transportation modes scientifi-cally in order to organize container transportation efficiently in this area and make decision for integral plan and construction of transportation system in this area. This paper outlines application of fuzzy comprehensive evaluation to appraise different modes of typical direction of containers. Twelve assessment indexes were decided. Membership functions were formulated. Evaluation results indicated that road transportation was optimal mode in the Changjiang River delta area, however water transportation was the primary way in the Changjiang River main line.

  18. The ordered network structure and its prediction for the big floods of the Changjiang River Basins

    International Nuclear Information System (INIS)

    According to the latest statistical data of hydrology, a total of 21 floods took place over the Changjiang (Yangtze) River Basins from 1827 to 2012 and showed an obvious commensurable orderliness. In the guidance of the information forecasting theory of Wen-Bo Weng, based on previous research results, combining ordered analysis with complex network technology, we focus on the summary of the ordered network structure of the Changjiang floods, supplement new information, further optimize networks, construct the 2D- and 3D-ordered network structure and make prediction research. Predictions show that the future big deluges will probably occur over the Changjiang River Basin around 2013-2014, 2020-2021, 2030, 2036, 2051, and 2058. (orig.)

  19. The ordered network structure and its prediction for the big floods of the Changjiang River Basins

    Energy Technology Data Exchange (ETDEWEB)

    Men, Ke-Pei; Zhao, Kai; Zhu, Shu-Dan [Nanjing Univ. of Information Science and Technology, Nanjing (China). College of Mathematics and Statistics

    2013-12-15

    According to the latest statistical data of hydrology, a total of 21 floods took place over the Changjiang (Yangtze) River Basins from 1827 to 2012 and showed an obvious commensurable orderliness. In the guidance of the information forecasting theory of Wen-Bo Weng, based on previous research results, combining ordered analysis with complex network technology, we focus on the summary of the ordered network structure of the Changjiang floods, supplement new information, further optimize networks, construct the 2D- and 3D-ordered network structure and make prediction research. Predictions show that the future big deluges will probably occur over the Changjiang River Basin around 2013-2014, 2020-2021, 2030, 2036, 2051, and 2058. (orig.)

  20. Satellite estimates of wide-range suspended sediment concentrations in Changjiang (Yangtze) estuary using MERIS data

    OpenAIRE

    Shen, F; W. Verhoef; Zhou, Y.; Salama, M.S.; X. Liu

    2010-01-01

    The Changjiang (Yangtze) estuarine and coastal waters are characterized by suspended sediments over a wide range of concentrations from 20 to 2,500 mg l-1. Suspended sediment plays important roles in the estuarine and coastal system and environment. Previous algorithms for satellite estimates of suspended sediment concentration (SSC) showed a great limitation in that only low to moderate concentrations (up to 50 mg l-1) could be reliably estimated. In this study, we developed a semi-empirical...

  1. Human impact on the historical change of CO2 degassing flux in River Changjiang

    Directory of Open Access Journals (Sweden)

    Zhang Jing

    2007-08-01

    Full Text Available Abstract The impact of water quality changes in River Changjiang (formally known as the Yangtze River on dissolved CO2 and silicate concentrations and seasonal carbon flux in the past several decades (1960s–2000 was evaluated, based on monitoring data from hydrographic gauge. It was found that dissolved CO2 and silicate in Changjiang decreased dramatically during this decades, as opposed to a marked increase in nutrient (e.g. NO3- concentrations. Our analyses revealed that dissolved CO2 in Changjiang was over-saturated with the atmosphere CO2, and its concentration had showed a declining trend since the 1960s, despite that fluvial DIC flux had maintained stable. Analysis results also suggested that the decrease in dissolved CO2 concentration was attributed to changes on the riverine trophic level and river damming activities in the Changjiang drainage basin. Due to the economic innovation (e.g. agriculture and industry development across the Changjiang watershed, fertilizers application and river regulations have significantly altered the original state of the river. Its ecosystem and hydrological condition have been evolving toward the "lacustrine/reservoir" autotrophic type prevailing with plankton. Accordingly, average CO2 diffusing flux to the atmosphere from the river had been reduced by three-fourth from the 1960s to 1990s, with the flux value being down to 14.2 mol.m-2.yr-1 in the 1990s. For a rough estimate, approximately 15.3 Mt of carbon was degassed annually into the atmosphere from the entire Changjiang drainage basin in the 1990s.

  2. Geochemical processes controlling dissolved selenium in the Changjiang (Yangtze) Estuary and its adjacent waters

    Institute of Scientific and Technical Information of China (English)

    WU Xiaodan; SONG Jinming; WU Bin; LI Tiegang; LI Xuegang

    2014-01-01

    Dissolved selenium in the Changjiang (Yangtze) Estuary and its adjacent waters was determined by hy-dride generation atomic fluorescence spectrometry to elucidate the source, behavior in estuary, adsorp-tion-desorption process and biological role. In surface water, Se(IV ) concentration ranged 0.05-1.14 nmol/L and Se(VI) concentration varied 0.01-1.20 nmol/L, with the means of 0.76 and 0.49 nmol/L, respectively. In bottom water, Se(IV) content varied 0.03-0.27 nmol/L and Se(VI) content ranged 0.04-0.85 nmol/L, with the averages of 0.10 and 0.40 nmol/L, respectively. High level of Se(IV ) was observed near the shore with a significant decrease towards the open sea, suggesting the continental input from the adjacent rivers. Large value of Se( VI) was found in bottom water, reflecting the release from suspended sediment. Besides, high value appeared in the same latitude of the Changjiang Estuary and Hangzhou Bay illustrated the effect of lat-eral mixing and the long-distance transport of selenium. Se(VI), more soluble, occupied higher percentage in aqueous environment. The presence of Se(IV ) resulted from the degradation of residue and the reduction of Se(VI) under anaerobic condition. The positive relationship to suspended particulate material (SPM) and negative correlation to depth indicated that Se(IV ) tended to be released from the high density particulate matter. Instead, Se(VI) content did not significantly relate to SPM since it generally formed inner-sphere complex to iron hydroxide. Se(IV ) content negatively varied to salinity and largely depended on the fresh-water dilution and physical mixing. While, Se( VI) level deviated from the dilution line due to the in situ bio-geochemical process such as removal via phytoplankton uptake and inputs via organic matter regeneration. As the essential element, Se(IV) was confirmed more bioavailable to phytoplankton growth than Se(VI), and moreover, seemed to be more related to phosphorus than to nitrogen.

  3. QUANTITATIVE MODELING OF SUSPENDED SEDIMENT IN MIDDLE CHANGJIANG RIVER FROM MODIS

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Remote sensing techniques have been widely used to observe bodies of water. Among satellite sensors commonly used for water quality studies, the Moderate-resolution Imaging Spectroradiometer (MODIS) has potential in water quality monitoring, because of its moderate spatial resolution and high temporal resolution. In this paper, the utility of MODIS data for suspended sediment monitoring in the middle Changjiang (Yangtze) River is studied. It is concluded that suspended sediment concentration correlates well with reflectance values (R1-R2)/(Ri+R2) retrieved from MODIS 250m image data (R2=0.72, n=41). Based on this correlation, we obtain the empirical model of suspended sediment concentration in the middle Changjiang River from MODIS. It is shown that it is useful for MODIS data to monitor this parameter of water quality.

  4. Yangtze River Delta, The Works of Nature

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ The Yangtze River Delta or Yangtze Delta,also called Chang Jiang Delta,or the Golden Triangle of the Yangtze,generally comprises the triangular-shaped territory of Wu-speaking Shanghai,southern Jiangsu province and northern Zhejiang province of China.The area lies at the heart of the region traditionally called Jiangnan.The Yangtze River drains into the East China Sea.

  5. Seasonal variation of tidal prism and energy in the Changjiang River estuary: a numerical study

    Science.gov (United States)

    Zhang, Min; Townend, Ian Howard; Cai, Huayang; Zhou, Yunxuan

    2016-01-01

    Tidal rivers are intrinsically complex because tidal propagation is influenced by river discharge. This study aims to examine the seasonal variation of tidal prism and energy variance in the tidal river of the Changjiang (Yangtze) River estuary in China. In order to quantify the behaviour of river and tide, we use numerical modelling that has been validated using measured data. We conduct our analysis by quantifying the discharge and energy variance in separate components for both the river and the tide, during wet and dry seasons. We note various definitions of tidal prism and explore the difference between tidal discharge on the flood and ebb and tidal storage volume. The results show that the river discharge attenuates the tidal motion and reduces the tidal flood discharge but the tidal storage volume is approximately constant with different riverine discharge since part of the fresh water discharge is intercepted and captured in the estuary due to the backwater effect. It appears that the tidal discharge adjusts according to the variation of river discharge to keep a constant tidal storage volume. An analysis of the hydraulics shows that the transition from tidal dominance (at the mouth) to river dominance (upstream) depends on the location of tidal current reversal which varies from wet season to dry season. Duringthe wet season, the Changjiang River estuary is totally dominated by energy from fresh water discharge.

  6. Distribution and fluxes of suspended sediments in the offshore waters of the Changjiang (Yangtze) Estuary

    Institute of Scientific and Technical Information of China (English)

    WAN Xinning; LI Jiufa; SHEN Huanting

    2009-01-01

    The offshore waters of the Changjiang Estuary are the transitional areas where river-supplied water and sediment are transported to the sea, and material exchanges occur with the neighbored Hangzhou Bay and the Jiangsu waters. Field observations of currents and sediment properties were conducted to study temporal and spatial distributions of suspended sediments under various dynamical conditions. The high sediment concentrations were found to occur in the western and southern waters of the offshore, and the low concentrations occurred in the eastern and northern waters. This pattern of the suspended sediment concentration (SSC) distribution is obviously influenced by the runoff and tidal current. The significant difference of along-estuary SSC distribution indicates that the SSC is reduced gradually from the west to the east, and that in the spring tide is obviously higher than in the neap tide. The methods of mechanism analysis and equal-area grids were used to calculate the suspended sediment fluxes at the typical cross sections. It was found that 44 percent of total suspended sediments from the Changjiang River were deposited in the submarine delta, and more than 27 percent of sediments were transported southernly into the Hangzhou Bay, and only 9 percent of sediments was supplied and exchanged with the northern Jiangsu waters, and about 20 percent of sediments was delivered offshore to the sea.

  7. Historical trends of hypoxia in Changjiang River estuary: Applications of chemical biomarkers and microfossils

    Science.gov (United States)

    Li, X.; Bianchi, T.S.; Yang, Z.; Osterman, L.E.; Allison, M.A.; DiMarco, S.F.; Yang, G.

    2011-01-01

    Over the past two decades China has become the largest global consumer of fertilizers, which has enhanced river nutrient fluxes and caused eutrophication and hypoxia in the Yangtze (Changjiang) large river delta-front estuary (LDE). In this study, we utilized plant pigments, lignin-phenols, stable isotopes (δ13C and δ15N) and foraminiferal microfossils in 210Pb dated cores to examine the history of hypoxia in the Changjiang LDE. Two sediment cores were collected onboard R/V Dong Fang Hong 2 using a stainless-steel box-corer; one at a water depth of 24.7 m on Jun. 15, 2006 and the other at 52 m on Nov. 20, 2007, both in the hypoxic region off the Changjiang LDE. There has been a significant increase in the abundance of plant pigments after 1979 that are indicators of enhanced diatom and cyanobacterial abundance, which agrees with post-1980 record of increasing nutrient loads in the Changjiang River. The increased inputs of terrestrially derived materials to the LDE are largely woody plant sources and most likely due to deforestation that began in the early 1950s. However, post-1960 lignin data did not reflect enhanced loading of woody materials despite continued deforestation possibly due to increased trapping from greater dam construction, a reduction of deforestation in the drainage basin since the last 1990s, and soil conservation practices. The lack of linkages between bulk indices (stable isotopes, % OC, molar C/N ratios) and microfossil/chemical biomarkers may reflect relative differences in the amount of carbon tracked by these different proxies. Although NO3− is likely responsible for most of the changes in phytoplankton production (post 1970s), historical changes in N loading from the watershed and hypoxia on the LDE shelf may not be as well linked in East China Sea (ECS) sediments due to possible denitrification/ammonification processes; finally, increases in low-oxygen tolerant foraminiferal microfossils indicate there has been an increase in the

  8. Composition of fish communities in an intertidal salt marsh creek in the Changjiang River estuary, China

    Institute of Scientific and Technical Information of China (English)

    QUAN Weimin; NI Yong; SHI Liyan; CHEN Yaqu

    2009-01-01

    Fish communities in a (third-order) intertidal creek in Dongtan marsh in the Changjiang (Yangtze) River estuary were investigated seasonally for one year. A total of 1 996 fish specimens (10 967.8 g) comprising 26 species and 15 families were collected. Abundances of fish communities in the intertidal salt marsh creek were primarily dominated by Boleophthalmus pectinirostris (19.8%), Collichthys lucidus (18.6%), Periophthalmus magnuspinnatus (18.2%), Liza haematocheilus (17.9%), and secondarily by Mugilogobius abei (8.5%), L. carinatus (7.2%), Odontamblyopus lacepedii (4.3%), and Acanthogobius ommaturus (3.9%); another 18 species were present only occasionally. Non-MDS ordination and SIMPER analysis indicated that there were two fish communities in the intertidal salt marsh creek. In spring, the communities were dominated by B. pectinirostris, P. magnuspinnatus, C. lucidus and M. abei; in summer, autumn, and winter by L. haematocheilus, L. carinatus, A. ommaturus and O. lacepedii. Some species showed strong habitat selection; L. carinatus and P. magnuspinnatus were distributed mainly in the upper and middle creek, while B. pectinirostris, M. abei and O. lacepedii inhabited the middle and lower creek. The study indicated that the salt marshes of the Changjiang River estuary are an important nursery and feeding habitat for many fishes and should be protected.

  9. Zooplankton community analysis in the Changjiang River estuary by single-gene-targeted metagenomics

    Science.gov (United States)

    Cheng, Fangping; Wang, Minxiao; Li, Chaolun; Sun, Song

    2014-07-01

    DNA barcoding provides accurate identification of zooplankton species through all life stages. Single-gene-targeted metagenomic analysis based on DNA barcode databases can facilitate longterm monitoring of zooplankton communities. With the help of the available zooplankton databases, the zooplankton community of the Changjiang (Yangtze) River estuary was studied using a single-gene-targeted metagenomic method to estimate the species richness of this community. A total of 856 mitochondrial cytochrome oxidase subunit 1 (cox1) gene sequences were determined. The environmental barcodes were clustered into 70 molecular operational taxonomic units (MOTUs). Forty-two MOTUs matched barcoded marine organisms with more than 90% similarity and were assigned to either the species (similarity>96%) or genus level (similaritymetagenomic analysis is a useful tool for zooplankton studies, with which specimens from all life history stages can be identified quickly and effectively with a comprehensive database.

  10. Jiaxing: Delicacy of the Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    WUXINYI; WANGNAN

    2004-01-01

    THE yangtze River Delta,where the Yangtzc River crosses China's east coast,has one of the country's most dynamic economies.In 1976Jcan Gottmann.a french geographer,called shanghai and its neighboring Yangtze River Delta the world's "sixth largest megalopolis." The Yangtze River Delta has 15 cities. Its territory accounts for one percent of China's total, 5.8 percent of hthe population, and 19.5 percent of the national GDP.In terms of both aggregate economy and growth speed, the Delta currently leads China and could likely be the "enginc" of the world's future economic growth. Located at the juncition of Shanghai Jiangsu and Zhejiang, Jiaxing City holds a central economic belt. It is within 100 kilometers of Shanghai, Hangzhou and Suzhou. In 200 and 2003, Jiaxing's GDP growth rate was first in Zhejiang Province and second among the 1.5 Delta cities.

  11. Huang Daopo and the Rise of the Changjiang River Delta

    Institute of Scientific and Technical Information of China (English)

    PengAnyu

    2005-01-01

    The Changjiang River Delta centered on Shanghai was originally not a cotton growing area, and hence had no cotton textile industry to speak of. By the Tang Dynasty, cotton cloth was no longer a rare sight in the area, but cotton was still not grown there. The people still relied on silkworm breeding and mulberry growing for a living, and were known throughout the country for their silk fabrics. It was not until the late Southern Song Dynasty that cotton growing began to appear, as evidenced by the late Song poet Ai Keshu's poem “Ode to Silk Cotton.”

  12. Recent morphodynamic evolution of the largest uninhibited island in the Yangtze (Changjiang) estuary during 1998-2014: Influence of the anthropogenic interference

    Science.gov (United States)

    Wei, Wen; Mei, Xuefei; Dai, Zhijun; Tang, Zhenghong

    2016-08-01

    Estuarine geomorphology worldwide has greatly changed in the Anthropocene due to intensive human inferences in river basin and within estuary, which has received increasing global concerns. Here, recent morphodynamic evolution of Jiuduan Shoal (JDS), the largest uninhabited island in the Yangtze (Changjiang) Estuary, and associated controlling factors were analyzed based on unique high-resolution seasonal-surveyed bathymetric data during 1998-2014. It can be indicated that JDS presents novel 12 and 48 months fluctuations though significant accretion was detected on high flats above -2 m. Meanwhile, morphodynamic evolution of JDS during 1998-2014 was divided into three stages: significant siltation on landward half of north JDS and expanding of Jiangya Shoal (JYS, part of JDS) tail, but less accretion at high flats from 1998 to 2002; continuous variations of JYS and reshape of seaward JDS with erosion band and heave appearance from 2002 to 2006; retentive alteration of JYS but recovery of erosion band and heave, together with redistribution of sand between high and low flats on seaward JDS after 2007. Moreover, river discharge could be likely the key factor controlling periodic characteristics of recent JDS evolution. Deep waterway project (DWP) dominates area increase of JDS by inducing accretion in north edge and south edge of Lower Shoal between 1998 and 2014.

  13. Environmental Settings and Harmful Algal Blooms in the Sea Area Adjacent to the Changjiang River Estuary

    OpenAIRE

    Zhou, Mingjiang

    2010-01-01

    The characteristics of the environmental settings of the sea area adjacent to the Changjiang River estuary include complex currents and water masses, the diluted water plume and its redirection, upwelling, front, and nutrients and their sources. The Changjiang River estuary characteristics also include the phytoplankton community, which can affect the growth, migration, assembling, resting and competition of algae to form red tides in this area.. The features of red tide events recorded in th...

  14. Distribution of chlorophyll-a off the Changjiang River and its dynamic cause interpretation

    Institute of Scientific and Technical Information of China (English)

    ZHU Jianrong

    2005-01-01

    An interdisciplinary comprehensive survey was conducted in August 2000 with the modern measurement instruments off the Changjiang River. The analysis of the observation data shows that there exist two sources of phytoplankton blooms off the Changjiang River. The one with wider spatial extent and stronger intensity appears in the surface plume due to photosynthesis produced by the eutrophication brought by a huge amount of nutrient load via the Changjiang River and well light penetration because of lower turbidity seawater. Photosynthesis produces chlorophyll-a (Chl-a), meanwhile releases oxygen and absorbs carbon dioxide, so the high Chl-a concentration distribution corresponds to the distribution of high dissolved oxygen and pH.The other with smaller spatial extent and weaker intensity exists in the thermocline in the Taiwan Warm Current (TWC), but the high Chl-a concentration does not correspond to the high dissolved oxygen and pH, which may be a result of long distance advection by the TWC. The eutrophication associated with the huge amount of nutrient flowing into the sea via the Changjiang River is the main cause of the red tide bloom in the area off the Changjiang River, the red tide that occurred along the Fujian and Zhejiang coast can influence the area off the Changjiang River possibly via the TWC. The distributions of current simulated by a three-dimension numerical model support the above conclusion.

  15. Impacts of anthropogenic activities on the Changjiang (Yangtze) estuarine ecosystem (1998-2012)

    Institute of Scientific and Technical Information of China (English)

    CHEN Dong; DAI Zhijun; XU Ren; LI Daoji; MEI Xuefei

    2015-01-01

    Estuarine ecosystem has greatly changed in the recent decades due to anthropogenic perturbations in the Changjiang Estuary. Change patterns and impact factors were analyzed based on the continuous data in relation to the Changjiang estuarine ecosystem from 1998 to 2012. The results showed significant decreases in plankton species and annual output ofCoilia nasus,Coilia mystus. Furthermore, species and biomass of benthos showed abrupt change in 2003, downward before that and upward after that. It was noted that,Eriocheir sinensis, a high value commercial fish, had an annual production increase of 97%. Reduction of riverine nutrients, especially dissolved silicate (DSI) loads into the estuary could contribute to the decline inBacillariophyta species. Dredging and dumping works of the North Passage led to the decreases in regional plankton species. However, the species reproduction and releasing projects could restore the estuarine ecosystem through increasing the output ofE. sinensis, as well as species and biomass of benthos.

  16. Nutrient fluxes in the Changjiang River estuary and adjacent waters — a modified box model approach

    Science.gov (United States)

    Wang, Xiaohong; Yu, Zhiming; Fan, Wei; Song, Xiuxian; Cao, Xihua; Yuan, Yongquan

    2015-01-01

    To solve nutrient flux and budget among waters with distinct salinity difference for water-salt-nutrient budget, a traditional method is to build a stoichiometrically linked steady state model. However, the traditional way cannot cope appropriately with those without distinct salinity difference that parallel to coastline or in a complex current system, as the results would be highly affected by box division in time and space, such as the Changjiang (Yangtze) River estuary (CRE) and adjacent waters (30.75°2-31.75°N, 122°10'-123°20'E). Therefore, we developed a hydrodynamic box model based on the traditional way and the regional oceanic modeling system model (ROMS). Using data from four cruises in 2005, horizontal, vertical and boundary nutrient fluxes were calculated in the hydrodynamic box model, in which flux fields and the major controlling factors were studied. Results show that the nutrient flux varied greatly in season and space. Water flux outweighs the nutrient concentration in horizontal flux, and upwelling flux outweighs upward diffusion flux in vertical direction (upwelling flux and upward diffusion flux regions overlap largely all the year). Vertical flux in spring and summer are much greater than that in autumn and winter. The maximum vertical flux for DIP (dissolved inorganic phosphate) occurs in summer. Additional to the fluxes of the Changjiang River discharge, coastal currents, the Taiwan Warm Current, and the upwelling, nutrient flux inflow from the southern Yellow Sea and outflow southward are found crucial to nutrient budgets of the study area. Horizontal nutrient flux is controlled by physical dilution and confined to coastal waters with a little into the open seas. The study area acts as a conveyer transferring nutrients from the Yellow Sea to the East China Sea in the whole year. In addition, vertical nutrient flux in spring and summer is a main source of DIP. Therefore, the hydrodynamic ROMS-based box model is superior to the traditional

  17. Estimation of dissolved inorganic nutrients fluxes from the Changjiang River into estuary

    Institute of Scientific and Technical Information of China (English)

    刘新成; 沈焕庭

    2001-01-01

    Because the estuary acts as either a trap or a source or both for nutrient elements and will modify greatly the riverine transport to the ocean, it is necessary to calculate the flux from river into estuary and that from estuary into sea, respectively. The present work aims to use a long-term record of nutrients concentrations and runoff discharges on H.e Datong section (625 km inland from the Changjiang River mouth) to identify the variability of nutrients concentrations and to estimate nutrients fluxes from the Changjiang River into the estuary.

  18. Downstream Yangtze River Levels Impacted by Three Gorges Dam

    NARCIS (Netherlands)

    Wang, J.; Sheng, Y.; Gleason, C.J.; Wada, Y.

    2013-01-01

    Changes in the Yangtze River level induced by large-scale human water regulation have profound implications on the inundation dynamics of surrounding lakes/wetlands and the integrity of related ecosystems. Using in situ measurements and hydrological simulation, this study reveals an altered Yangtze

  19. The change of characteristics of tidal wave in the Changjiang River mouth area since the post-glacial transgression maximum

    Institute of Scientific and Technical Information of China (English)

    朱玉荣

    2001-01-01

    During the period of the post-glacial transgression maximum (PGTM), there was a huge trumpet estuary in the modern Changjiang River Delta area. The location and the shape of the Paleo-Changjiang River Estuary (PCRE) were much different from those of the present Chang-Jiang River Estuary. The study on the change of characteristics of tidal wave in the Changjiang River mouth area since the PGTM can help to understand better the dynamic development of the Changjiang River Delta. The course curves of tidal level and tidal current velocity during a single tidal cycle for 35 points are calculated, and characteristics of tidal waves in the PCRE and its adjacent area are compared with those of tidal waves in the modern Changjiang River mouth area. The results show that the tidal waves within the PCRE and in its adjacent area during the period of the PGTM belonged to standing wave or a mixture of standing wave and progressive wave. Since then, the tidal wave in the Changjiang River mouth become gradually to be pr

  20. Analysis on River Sediment Changes of the Upper Reaches of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    ZHONG Xiang-hao; SHI Guo-yu; XU Quan-xi; CHEN Ze-fang; LIU Shu-zhen

    2005-01-01

    The sediment load and river sedimentation of the upper reaches of Yangtze River has been undergoing constant changes as complex landform, large mountain area and plentiful precipitation make the drainage area of Yangtze River very vulnerable to water erosion and gravity erosion. Through analyzing the hydrological and sediment load statistics recorded by major hydrological stations along Yangtze River since 1950s, and editing the accumulation graph of annual runoff volume and annual sediment load, we find out that the suspended-sediment of Yangtze river has been decreasing year by year in Wulong Hydrological Station on Wujiang River, Beibei Hydrological Station on Jialingjiang River, Lijiawan Hydrological Station on Tuojiang River and Gaochang Hydrological Station on Minjiang River, Yichang Hydrological Station, Cuntan Hydrological Station along Yangtze River mainstream share the same experience too. But the statistics obtained at Pingshan Hydrological Station on Jinshajiang River shows the sediment load there has increased. Taking ecological construction, hydraulic engineering construction and precipitation changes into consideration, the thesis analyses the causes for the sediment load decrease of Jialingjiang River, Tuojiang River, Minjiang River and Wujiang River and provides us both scientific foundation for further study of river sediment changes of the upper reaches of Yangtze River, and measures to control river sedimentation.

  1. Riverbed Micromorphology of the Yangtze River Estuary, China

    Directory of Open Access Journals (Sweden)

    Shuaihu Wu

    2016-05-01

    Full Text Available Dunes are present in nearly all fluvial channels and are vital in understanding sediment transport, deposition, and flow conditions during floods of rivers and estuaries. This information is pertinent for helping developing management practices to reduce risks in river transportation and engineering. Although a few recent studies have investigated the micromorphology of a portion of the Yangtze River estuary in China, our understanding of dune development in this large estuary is incomplete. It is also poorly understood how the development and characteristics of these dunes have been associated with human activities in the upper reach of the Yangtze River and two large-scale engineering projects in the estuarine zone. This study analyzed the feature in micromorphology of the entire Yangtze River estuary bed over the past three years and assessed the morphological response of the dunes to recent human activities. In 2012, 2014, and 2015, multi-beam bathymetric measurements were conducted on the channel surface of the Yangtze River estuary. The images were analyzed to characterize the subaqueous dunes and detect their changes over time. Bottom sediment samples were collected for grain size analysis to assess the physical properties of the dunes. We found that dunes in the Yangtze River estuary can be classified in four major classes: very large dunes, large dunes, medium dunes, and small dunes. Large dunes were predominant, amounting to 51.5%. There was a large area of dunes developed in the middle and upper reaches of the Yangtze River estuary and in the Hengsha Passage. A small area of dunes was observed for the first time in the turbidity maximum zone of the Yangtze River estuary. These dunes varied from 0.12 to 3.12 m in height with a wide range of wavelength from 2.83 to 127.89 m, yielding a range in height to wavelength of 0.003–0.136. Sharp leeside slope angles suggest that the steep slopes of asymmetrical dunes in the middle and upper

  2. Joint effect of freshwater plume and coastal upwelling on phytoplankton growth off the Changjiang River

    Directory of Open Access Journals (Sweden)

    Y.-F. Tseng

    2013-06-01

    Full Text Available Changjiang River discharges vast amount of unbalanced nutrients (dissolved inorganic nitrogen (N and phosphorus (P with N / P > 80 in general into the East China Sea during summertime. To explore nutrient dynamics and P stress potential for phytoplankton, a cruise was conducted in the Changjiang plume during summer 2011. With 3-D observations of nutrients, chlorophyll a (Chl a, and bulk alkaline phosphatase activity (APA, we concluded that the Changjiang Diluted Water (CDW and coastal upwelling significantly influenced the horizontal and vertical heterogeneities of phytoplankton P-deficiency in the plume. Allochthonous APA was detected at nutrient-enriched freshwater end. Excessive N (~10 to 112 µM was obserevd throughout the entire plume surface. In the plume fringe where featured by stratification and excess N, diapycnal phosphate supply was blocked to stimulate APA for phytoplankton growth. We observed upwelling outcrops just attaching the turbidity front at seaward side, where Chl a peaked yet much less APA was detected. An external phosphate supply from subsurface, which stimulated phytoplankton growth but inhibited APA, was suggested and the supply was likely sourced from the Nearshore Kuroshio Branch Current. In such hydrographically complicated Changjiang plume, phosphate supply instead of its concentration was more important determining the expression of APA. Meanwhile, allochthounous APA may also alter the usefulness of APA as a P-stress indicator.

  3. Zooplankton spatial and diurnal variations in the Changjiang River estuary before operation of the Three Gorges Dam

    Institute of Scientific and Technical Information of China (English)

    GAO Xuelu; SONG Jinming; LI Xuegang

    2011-01-01

    Estuarine plankton communities can serve as indicators of ecosystem modification in response to anthropogenic influences. The main objectives of this study were to describe the spatial distribution and diurnal variability in zooplankton abundance and biomass over almost entire salinity gradient of the Changjiang (Yangtze) River estuary and to provide a background reference for future studies. To accomplish this, data were collected from 29 stations in the estuary from May 19 to 26, 2003,including two anchor stations. The spatial and diurnal variations in zooplankton characteristics, i.e.abundance, biomass, and gross taxonomic composition, were examined. Generally, both the abundance and biomass gradually increased seaward and presented distinct spatial variations. In addition, the spatial data revealed a significant correlation between abundance and biomass; however, there was no significant correlation between abundance and biomass for the diurnal data. Although the zooplankton composition indicated distinct spatial differences in terms of dominant groups, copepods accounted for >50% of the total zooplankton abundance in most regions and times. Three zooplankton assemblages were recognized through hierarchical cluster analysis. These assemblages existed along the salinity gradient from fresh water to seawater, and their positions coincided with those of the three principal water masses in the estuary. The assemblages were classified as: (1) true estuarine, (2) estuarine and marine, and (3) euryhaline marine, which were characterized by the copepods Sinocalanus dorrii, Labidocera euchaeta, and Calanus sinicus, respectively. Both spatial and diurnal data indicated that there was no significant correlation between zooplankton abundance/biomass and depth-integrated phytoplankton abundance.

  4. Detrital phosphorus as a proxy of flooding events in the Changjiang River Basin

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Jia [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Qingdao 266100 (China); College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100 (China); Yao, Peng, E-mail: yaopeng@mail.ouc.edu.cn [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Qingdao 266100 (China); Qingdao Collaborative Innovation Center of Marine Science and Technology, Qingdao 266100 (China); Institute of Marine Organic Geochemistry, Ocean University of China, Qingdao 266100 (China); Bianchi, Thomas S. [Department of Geological Sciences, University of Florida, Gainesville, FL 32611-2120 (United States); Li, Dong; Zhao, Bin; Xu, Bochao [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Qingdao 266100 (China); College of Chemistry and Chemical Engineering, Ocean University of China, Qingdao 266100 (China); Yu, Zhigang [Key Laboratory of Marine Chemistry Theory and Technology, Ministry of Education, Qingdao 266100 (China); Institute of Marine Organic Geochemistry, Ocean University of China, Qingdao 266100 (China)

    2015-06-01

    In this study, sediment grain size (MGS), specific surface area (SSA), total organic carbon (TOC) contents, C/N molar ratios, stable carbon isotope, and P species in a sediment core, collected from the East China Sea (ECS) inner-shelf were measured to explore the applicability of detrital phosphorus (De-P) as a potential indicator of past flooding events in the Changjiang River Basin (CRB). In particular, we examined the linkages between the evolution of floods with regional climate changes and anthropogenic activities in the CRB. Peaks of De-P concentrations in sediments corresponded well with the worst flooding events of the CRB over the past two centuries (e.g., 1850s, 1860s, 1900s, 1920s, 1950s, 1980s, and 2000s). Moreover, De-P also corresponded well with the extreme hypoxic events in 1981 and 1998 in the Changjiang Estuary as indicated by Mo/Al ratios, indicating potential linkages between De-P as a flooding proxy to flood-induced hypoxia events in this region. In addition, a robust relationship was found among De-P, the floods in 1950s, 1980s, and 2000s of the CRB, the intensive El Niño-Southern Oscillation (ENSO), the abnormally weak East Asian Summer Monsoon (EASM) and the warm phase of Pacific Decadal Oscillation (PDO), suggesting that De-P also provided insights to linkages between regional climate change and flooding events in this region. - Highlights: • De-P was used to track past floods in the Changjiang River Basin (CRB). • De-P may serve as a proxy for flood-induced hypoxia events in the Changjiang Estuary. • De-P may be a proxy for examining linkages between floods and climatic drivers.

  5. Detrital phosphorus as a proxy of flooding events in the Changjiang River Basin

    International Nuclear Information System (INIS)

    In this study, sediment grain size (MGS), specific surface area (SSA), total organic carbon (TOC) contents, C/N molar ratios, stable carbon isotope, and P species in a sediment core, collected from the East China Sea (ECS) inner-shelf were measured to explore the applicability of detrital phosphorus (De-P) as a potential indicator of past flooding events in the Changjiang River Basin (CRB). In particular, we examined the linkages between the evolution of floods with regional climate changes and anthropogenic activities in the CRB. Peaks of De-P concentrations in sediments corresponded well with the worst flooding events of the CRB over the past two centuries (e.g., 1850s, 1860s, 1900s, 1920s, 1950s, 1980s, and 2000s). Moreover, De-P also corresponded well with the extreme hypoxic events in 1981 and 1998 in the Changjiang Estuary as indicated by Mo/Al ratios, indicating potential linkages between De-P as a flooding proxy to flood-induced hypoxia events in this region. In addition, a robust relationship was found among De-P, the floods in 1950s, 1980s, and 2000s of the CRB, the intensive El Niño-Southern Oscillation (ENSO), the abnormally weak East Asian Summer Monsoon (EASM) and the warm phase of Pacific Decadal Oscillation (PDO), suggesting that De-P also provided insights to linkages between regional climate change and flooding events in this region. - Highlights: • De-P was used to track past floods in the Changjiang River Basin (CRB). • De-P may serve as a proxy for flood-induced hypoxia events in the Changjiang Estuary. • De-P may be a proxy for examining linkages between floods and climatic drivers

  6. Dynamic mechanism of the upwelling on the west side of the submerged river valley off the Changjiang mouth in summertime

    Institute of Scientific and Technical Information of China (English)

    ZHU Jianrong

    2003-01-01

    Based on the analysis of the field observation data off the Changjiang mouth in August 2000 and satellite image of sea surface temperature (SST) in summer of 1997, it indicates that there exists the upwelling event on the west side of the submerged river valley (SRV) off the Changjiang mouth. The calculated results of the three-dimensional numerical model show that this upwelling is induced by the barotropic effect, baroclinic effect, bottom Ekman effect and their interaction with the slope bottom topography. The baroclinic effect is the main cause producing the upwelling at the northern SRV (on the east side of the South Passage of the Changjiang estuary), while the barotropic effect is the main cause at the southern SRV (on the east side of the center of the Hangzhou Bay mouth). The dynamic mechanism producing the upwelling off the Changjiang mouth is different with the general one along coast and on the continental shelf.

  7. On the siltation of the middle Yangtze River

    Institute of Scientific and Technical Information of China (English)

    YIN Hongfu; CHEN Guojin; LI Chang'an; WEI Yuan

    2004-01-01

    About 5.2×108 t/a of silts from the upper reach of the Yangtze River are transported through Yichang into the middle Yangtze River. The middle Yangtze itself and its tributaries yield ca. 0.8×108 t silts annually. Of this total 6×108 t/a input of silts, ca. 1.2×108 t/a are deposited within the river artery and lakes, while ca 4.83×108 t/a are at first transported into the lower reach through Datong, and then either deposited along the river and the Yangtze Delta, or output into the sea. Along the middle Yangtze River silting generally exceeds scouring, but the spatial and temporal distributions of scour-and-fill, as well as its distribution in the river valley transections, are uneven. Along the Yichang-Chenglingji and Jiujiang-Datong Segments of the middle Yangtze, scouring exceeds or equals silting. Silting mainly occurs along the Luoshan-Wuhan-Huangshi Segments with Wuhan as the pivotal point, as well as in the Dongting and Poyang Lakes. Even in these silting-dominated areas, there are times and parts of segments that scouring prevails. As to the transections, generally the river channel of main stream is scouring-dominated, forming V-shaped sections to a depth of 20-30 m or more, whereas the floodplains and bar islands are silting-dominated, forming wide and relatively high flats, which are often artificially transformed into protected embankments. Because the Jingjiang Levee separates the Jianghan Plain from Yangtze to the south, little has been deposited in that plain except a few sediments from the Han River-a tributary of the middle Yangtze. This factor plus the tectonic sag of that plain has made the altitude of plain surface several meters lower than that of the levee in most of the areas. Siltation along the Luoshan-Wuhan-Huangshi Segments has resulted in the elevation of flood level in this and upstream segments. River channel scouring plus floodplain silting have caused the transections of the middle Yangtze valley typically with deep channel and

  8. Progradation of the Changjiang River delta since the mid-Holocene

    Institute of Scientific and Technical Information of China (English)

    HoriKazuaki; SaitoYoshiki; 赵泉鸿; 汪品先; 李从先

    2001-01-01

    Subaqueous deltaic deposits with approximately 30 radiocarbon ages show that the Changjiang River delta was strongly affected by tides and that the delta progradation rate after 2 kaBP was almost double the rate before 2 kaBP. This change in the progradation rate correlates well with the active extension of the subaerial delta plain shown by previous work. Widespread human activities, such as farming, deforestation, and dike construction, probably resulted in an increase in sediment discharge to the river-mouth area.

  9. Structural safety monitoring for Nanjing Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    黄方林; 何旭辉; 陈政清; 曾储惠

    2004-01-01

    In order to evaluate objectively and accurately the integrity, safety and operating conditions in real time for the Nanjing Yangtze River Bridge, a large structural safety monitoring system was described. The monitoring system is composed of three parts: sensor system, signal sampling and processing system, and safety monitoring and assessment system. Combining theoretical analysis with measured data analysis, main monitoring contents and layout of measuring points were determined. The vibration response monitoring was significantly investigated. The main contents of safety monitoring on vibration response monitoring are vibration of the main body of the Nanjing Yangtze river bridge, collision avoidance of the bridge piers, vibration of girders on high piers for the bridge approach and earthquake. As a field laboratory, the safety monitorying system also provides information to investigate the unknown and indeterminate problems on bridge structures and specific environment around bridges.

  10. Yangtze River Delta and Railway Construction in Sustainable Development

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Yangtze River Delta is the most developed economy and society as well as one of the most densely populated and industrialized regions in China.It is also one of the most dynamic regions with the biggest potential and competitiveness to radiate and generate impetus to the trade development in the middle and western parts of China and in the world.The implementation of sustainable development strategy in the region urgently needs to improve the transportation structure and to solve the problems of constraints and "bottlenecks ".It is necessary to have the global view and insight and catering to the needs of the future to build outbound major railway corridors with a view to enhance the influential and attractive capacities of the Yangtze River Delta region;achieve the goals of construction of intercity railway lines with high standards to form integrated railway systems of the region;and speed up the construction of major hubs in the key cities 'integrated railway system so as to realize easy connection of various modes of transport and improve the railway construction programs with coordinated development of infrastructure.In the meantime,the advantages of different modes will be brought into play to accelerate the harmonious railway development of the Yangtze River Delta region in an all round way.

  11. Reflections on Development Strategy of Pearl River Delta: In Comparison with Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    <正>1. A comparison between Pearl River Delta and Yangtze River Delta 1.1 Basic conditions 1.1.1 Location, area and scope Located in the southeast of Guangdong Province, the Pearl River Delta (PRD) as an economic zone is a compound delta

  12. The variations of suspended sediment concentration in Yangtze River Estuary

    Institute of Scientific and Technical Information of China (English)

    杨云平; 张明进; 李义天; 张为

    2015-01-01

    With the Yangtze River Estuary as an example, this paper analyzes the influence of human activity on the sea water content, the sediment content and the regional transport situation. In both flood seasons and dry seasons, as well as in the whole year, the sediment discharge rate and the suspended sediment concentration (SSC) in the estuary area of the Yangtze River show decreasing trends. In the estuary area, the amount of sediment transported into the South and North Branches and the offshore area is also in a decreasing trend over the years. The SSCs at the sections at the entrances of the South Branch, the South Channel, the North Channel and the South Passage in the Yangtze River Estuary show decreasing trends during 1959-2011. The remote-sensing data reveal that for the same runoff and tidal current combination, the SSC in the surface water is decreased, caused by the dramatic decrease in the sediment discharge and the sediment content from the watershed. Although the SSC in the offshore area does not exhibit an apparent decreasing trend, the SSC in the nearshore area drops by 21.42% during the period of 2003-2011 as compared with that during the period of 1985-2002 before the impounding of the Three Gorges Reservoir. The sediment re-suspension in the estuary slows down the reduction of the SSC. The period of 2003-2011 is dry years for the Yangtze River, when the flow is relatively low. The peak value of the SSC in the coast area shifts inwards for about 1/6°degree of longitude. Due to the deepwater channel improvement project in the North Passage at the Yangtze River Estuary in 1998, the SSC in the waterway area is decreased. With the decrease of the divided flow ratio and the sediment splitting ratio in the entrance and the exit of the North Passage, the SSC in the upper and lower reaches of the North Passage during the period of 2008-2011 is decreased by about 14.25% as compared with that during the period of 2000-2007. Primarily due to the jetty at the

  13. The main phosphorous sources in the Changjiang estuary

    Institute of Scientific and Technical Information of China (English)

    YANG Dongfang; WANG Fan; MIAO Zhenqing; CHEN Yongli; TONG Yuanzheng

    2008-01-01

    Analysis using historical data on the phosphate sources in Changjiang (Yangtze River) estuary show that phosphate was supplied equally from the east, south, west and north of the estuary. These sources include the Changjiang River, the Taiwan Warm Current (TWC), a cyclone-type eddy, and the 32°N Upwelling, supplying different phosphates in different times, ways and intensities. The magnitude of their supplying phosphate concentration was related with the size in the order of the Changjiang River < the TWC < the 32°N Upwelling < the cyclone-type eddy, and the duration of the supplying was: the Changjiang River the TWC the cyclone-type eddy the 32°N Upwelling. The four sources supplied a great deal of phosphate so that the phosphate concentration in the estuary was kept above 0.2 μmol/L in previous years, satisfying the phytoplankton growth. The horizontal and vertical distribution of the phosphate concentration showed that near shallow marine areas at 122°E/31°N, the TWC in low nutrient concentration became an upwelling through sea bottom and brought up nutrients from sea bottom to marine surface. In addition, horizontal distribution of phosphate concentration was consistent with that of algae: Rhizosolenia robusta, Rhizosolenia calcaravis and Skeletonema, which showed that no matter during high water or low water of Changjiang River, these species brought by the TWC became predominant species. Therefore, the authors believe that the TWC flowed from south to north along the coast and played a role in deflecting the Changjiang River flow from the southern side.

  14. Characteristics of the δ ^{15} N_{NO_3 } distribution and its drivers in the Changjiang River estuary and adjacent waters

    Science.gov (United States)

    Wang, Wentao; Yu, Zhiming; Song, Xiuxian; Wu, Zaixing; Yuan, Yongquan; Zhou, Peng; Cao, Xihua

    2016-05-01

    In this study, we conducted investigations in the Changjiang (Yangtze) River estuary and adjacent waters (CREAW) in June and November of 2014. We collected water samples from different depths to analyze the nitrogen isotopic compositions of nitrate, nutrient concentrations (including inorganic N, P, and Si), and other physical and biological parameters, along with the vertical distribution and seasonal variations of these parameters. The compositions of nitrogen isotope in nitrate were measured with the denitrifier method. Results show that the Changjiang River diluted water (CDW) was the main factor aff ecting the shallow waters (above 10 m) of the CREAW, and CDW tended to influence the northern areas in June and the southern areas in November. δ ^{15} N_{NO_3 } values in CDW ranged from 3.21‰-3.55‰. In contrast, the deep waters (below 30 m) were aff ected by the subsurface water of the Kuroshio Current, which intruded into the waters near 31°N in June. The δ ^{15} N_{NO_3 } values of these waters were 6.03‰-7.6‰, slightly higher than the values of the Kuroshio Current. Nitrate assimilation by phytoplankton in the shallow waters of the study area varied seasonally. Because of the favorable temperature and nutrient conditions in June, abundant phytoplankton growth resulted in harmful algae blooms (HABs). Therefore, nitrate assimilation was strong in June and weak in November. The δ ^{15} N_{NO_3 } fractionations caused by assimilation of phytoplankton were 4.57‰ and 4.41‰ in the shallow waters in June and November, respectively. These results are consistent with previous laboratory cultures and in situ investigations. Nitrification processes were observed in some deep waters of the study area, and they were more apparent in November than in June. The fractionation values of nitrification ranged from 24‰-25‰, which agrees with results for Nitrosospira tenuis reported by previous studies.

  15. Water discharge changes of the Changjiang River downstream Datong during dry season

    Institute of Scientific and Technical Information of China (English)

    CHENXiqing; WANGXiaoli; ZHANGErfeng

    2003-01-01

    Based on hydrometric data and extensive investigations on water-extracting projects, this paper presents a preliminary study on water discharge changes between Datong and Xuliujing during dry season. The natural hydrological processes and human factors that influence the water discharge are analyzed with the help of GIS method. The investigations indicate that the water-extracting projects downstream from Datong to Xuliujing had amounted to 64 in number by the end of 2000,with a water-extracting capacity up to 4,626 m3/s averaged in a tidal cycle. The water extraction from the Changjiang River has become the most important factor influencing the water discharge downstream Datong during dry season. The potential magnitude in water discharge changes are estimated based on historical records of water extraction and a water balance model. The computational results were calibrated with the actual data. The future trend in changes of water discharge into the sea during dry season was discussed by taking into consideration of newly built hydro-engineering projects. The water extraction downstream Datong in dry season before 2000 had a great influence on discharges into the sea in the extremely dry year like 1978-1979. It produced a net decrease of more than 490 m3/s in monthly mean discharges from the Changjiang into the sea. It is expected that the water extraction will continually increase in the coming decades, especially in dry years, when the net decrease in monthly mean water discharge will increase to more than 1000 m3/s and will give a far-reaching effect on the changes of water discharge from the Changjiang into the sea.

  16. The Relation between Atmospheric Intraseasonal Oscillation and Summer Severe Flood and Drought in the Changjiang-Huaihe River Basin

    Institute of Scientific and Technical Information of China (English)

    杨辉; 李崇银

    2003-01-01

    The intraseasonal oscillation (ISO) is studied during the severe flood and drought years of the Changjiang-Huaihe River Basin with the NCEP/NCAR reanalysis data and the precipitation data in China. The results show that the upper-level (200 hPa) ISO pattern for severe flood (drought) is charac-terized by an anticyclonic (cyclonic) circulation over the southern Tibetan Plateau and a cyclonic (anti-cyclonic) circulation over the northern Tibetan Plateau. The lower-level (850 hPa) ISO pattern is char-acterized by an anticyclonic (cyclonic) circulation over the area south of the Changjiang River, the South China Sea, and the Western Pacific, and a cyclonic (anticyclonic) circulation from the area north of the Changjiang River to Japan. These low-level ISO circulation patterns are the first modes of the ISO wind field according to the vector EOF expansion with stronger amplitude of the EOF1 time coefficient in se-vere flood years than in severe drought years. The analyses also reveal that at 500 hPa and 200 hPa,the atmospheric ISO activity over the Changjiang-Huaihe River basin, North China, and the middle-high latitudes north of China is stronger for severe flood than for severe drought. The ISO meridional wind over the middle-high latitude regions can propagate southwards and meet with the northward propagating ISO meridional wind from lower latitude regions over the Changjiang-Huaihe River Basin during severe flood years, but not during severe drought years.

  17. HYDRODYNAMIC CHARACTERISTICS OF CHINESE STURGEON SPAWNING GROUND IN YANGTZE RIVER

    Institute of Scientific and Technical Information of China (English)

    YANG Yu; YAN Zhong-min; CHANG Jian-bo

    2008-01-01

    Since the construction of the Gezhouba Dam on the Yangtze River in 1981, it has been found that the Chinese Sturgeon, Acipensor sinensis, performs natural propagation annually in a narrow reach downstream close to the Gezhouba Dam site. This might allow one to better investigate the river hydrodynamic conditions of the Chinese Sturgeon spawning ground. In this article, spatial Kinetic Energy Gradient (KEG) and absolute value of vorticity were computed along the river sections from measured data. The relation between Spawn Density per Unit Area (SDUA) and vorticity strength and between SDUA and KEG were worked out. The Results showed that the vorticity and KEG were both effective parameters for describing the hydrodynamic characteristics of Chinese Sturgeon spawning ground. The Chinese Sturgeons prefer to spawn in the river sections where the value of vorticity strength is larger than 0.4 s-1 and KEG is larger than 0.029 Jkg-1m-1.

  18. ADCP measured flow current of the middle-lower Changjiang River channel

    Institute of Scientific and Technical Information of China (English)

    Qiang ZHANG; Yafeng SHI; Zhongyuan CHEN; Tong JIANG

    2008-01-01

    The water column flow velocity of 36 river sections in the river reach between Hankou (Wuhan) and Wuxue of the middle-lower Changjiang River.Their cross sectional distribution patterns in relation to the river channel morphologies were examined by using shipmounted ADCP (Acoustic Doppler Current Profiler) instrument.The results indicate four (Ⅰ-Ⅳ) types of river channel morphology associated flow patterns:Ⅰ-laterally deepening riverbed topographic pattern; Ⅱ-symmetrical to asymmetrical riverbed topographic pattern; Ⅲ-relative fiat riverbed topographic pattern,and Ⅳ-sandbar supported riverbed topographic pattern.All these correspond to the different patterns of flow velocity distribution.The maximum flow velocity is usually related to the deeper water depth,but irregular water column distribution of flow current velocity results often from the vortices' current associated with river knots.Deeper river water depth is usually identified in the river reach located slightly downstream to the river knot,where faster flow velocity occurs.Downward change in flow velocity fits semi-log law,showing an exponential decreasing flow current with the maximum flow velocity near the water surface.However,in the river reach near the river knots,the water column distribution of flow current velocity does not fit the semi-log law,showing the irregular flow current pattern.This study,in context of river catchment management,highlights the controls of riverbed morphology to the flow current structure,which will shed light on the post study of Three Gorges damming in 2009.

  19. Residential building thermal performance energy efficiency in Yangtze River basin

    Institute of Scientific and Technical Information of China (English)

    王厚华; 庄燕燕; 吴伟伟

    2009-01-01

    Using energy consumption software VisualDOE4.0,simulation was carried out on the energy consumption of a typical residential building in Yangtze River basin,with a focus on thermal performance of envelope each component and application of total heating recovery equipment. The effects of thermal performance of building envelope each component on energy efficiency ratio were analyzed. Comprehensive measures schemes of energy saving were designed by the orthogonal experiment. The energy efficiency ratios of different envelopes combination schemes were gained. Finally,the optimize combination scheme was confirmed. With the measurement dates,the correctness of the simulation dates was completely verified.

  20. Modeling Offshore Freshwater Dispersal from the Changjiang River and Controlling Factors During Summer

    Directory of Open Access Journals (Sweden)

    Jae-Hong Moon

    2012-01-01

    Full Text Available In this study we examine offshore transport and dispersal pathways of the freshwater discharge from the Changjiang River in the East China Sea (ECS, using a regional ECS model. Comparison between the results for 1996 and 1998 clearly shows that the summer monsoon winds play a significant role in spreading the freshwater discharge offshore and determining the dispersal of freshwater in the ECS. Analysis of 10-year simulation demonstrates that a northeastward freshwater transport to Jeju Island across the northwestern shelf of the ECS dominates during the summer period due to the surface Ekman flow by the southeasterly along-shore wind. Meanwhile, there is virtually no relationship between the amount of the summer discharge and the freshwater pathway toward Jeju Island. Our analysis also suggests that when the summer wind is relatively weak, another freshwater pathway toward the central ECS appears with the ambient along-shelf current between the Taiwan Strait and the Korea Strait.

  1. Impact of Yangtze River Water Transfer on the Water Quality of the Lixia River Watershed, China

    OpenAIRE

    Ma, Xiaoxue; Wang, Lachun; Wu, Hao; Li, Na; Ma, Lei; Zeng, Chunfen; Zhou, Yi; Yang, Jun

    2015-01-01

    To improve water quality and reduce the negative impacts of sudden inputs of water pollution in the Lixia River watershed, China, a series of experimental water transfers from the Yangtze River to the Lixia River were conducted from 2 December 2006 to 7 January 2007. Water samples were collected every six days at 55 monitoring sites during this period. Eight water parameters (water temperature, pH, dissolved oxygen (DO), chemical oxygen demand (COD), potassium permanganate index (CODMn), ammo...

  2. GROWTH OF NEW ECONOMIC SECTORS IN SECOND-TIER EXTENDED CITIES IN THE CHANGJIANG RIVER DELTA--Case of Suzhou, Wuxi, Changzhou

    Institute of Scientific and Technical Information of China (English)

    CHEN Wen; SUN Wei; XIANG Jun-bo

    2004-01-01

    The second-tier extended metropolises in the Changjiang (Yangtze) River Delta, including Suzhou, Wuxi and Changzhou near Shanghai, are becoming the most active and new innovative industrial agglomerating areas. Manufacturing industries in these second-tier cities have been in rapid growth due to increasing foreign investment. Nevertheless, the economic prospect of these cities is still constrained by a lack of local R&D capacity and production services, which are mainly dependent upon Shanghai. This paper analyses the impact of globalization on the new economic sectors in these cities, the change of industrial structure, the limitation of urban development and the problem of sustainability. Then, the paper analyses the conditions for the high-tech industry and production services in these areas. Also, it applies the industrial organization theory to these cities and examines how these cities can cooperate with each other in terms of horizontal linkages. Finally, the paper gives the future growth prospects in high-tech industry and production services.

  3. Biocides in the Yangtze River of China: Spatiotemporal distribution, mass load and risk assessment

    International Nuclear Information System (INIS)

    Nineteen biocides were investigated in the Yangtze River to understand their spatiotemporal distribution, mass loads and ecological risks. Fourteen biocides were detected, with the highest concentrations up to 166 ng/L for DEET in surface water, and 54.3 ng/g dry weight (dw) for triclocarban in sediment. The dominant biocides were DEET and methylparaben, with their detection frequencies of 100% in both phases. An estimate of 152 t/y of 14 biocides was carried by the Yangtze River to the East China Sea. The distribution of biocides in the aquatic environments was significantly correlated to Gross Domestic Product (GDP), total phosphorus (TP) and total nitrogen (TN), suggesting dominant input sources from domestic wastewater of the cities along the river. Risk assessment showed high ecological risks posed by carbendazim in both phases and by triclosan in sediment. Therefore, proper measures should be taken to reduce the input of biocides into the river systems. - Highlights: • Biocides were ubiquitous in the surface water and sediment of the Yangtze River. • The dominant biocides in the Yangtze River were DEET and methylparaben. • Annual flux of biocides was 152 tons from the Yangtze River to the East China Sea. • Domestic wastewater was the main source of the biocides. • Carbendazim and triclosan posed high ecological risks. - Biocides showed wide presence in the Yangtze River and some of them could pose high ecological risks to aquatic organisms

  4. Incorporation of formal safety assessment and Bayesian network in navigational risk estimation of the Yangtze River

    International Nuclear Information System (INIS)

    Formal safety assessment (FSA), as a structured and systematic risk evaluation methodology, has been increasingly and broadly used in the shipping industry around the world. Concerns have been raised as to navigational safety of the Yangtze River, China's largest and the world's busiest inland waterway. Over the last few decades, the throughput of ships in the Yangtze River has increased rapidly due to the national development of the Middle and Western parts of China. Accidents such as collisions, groundings, contacts, oil-spills and fires occur repeatedly, often causing serious consequences. In order to improve the navigational safety in the Yangtze River, this paper estimates the navigational risk of the Yangtze River using the FSA concept and a Bayesian network (BN) technique. The navigational risk model is established by considering both probability and consequences of accidents with respect to a risk matrix method, followed by a scenario analysis to demonstrate the application of the proposed model

  5. Hydrodynamic effects of reconnecting lake group with Yangtze River in China

    OpenAIRE

    Kang, Ling; Xiao-ming GUO

    2011-01-01

    The hydrodynamic effects of reconnecting a lake group with the Yangtze River were simulated using a three-dimensional hydrodynamic model. The model was calibrated and validated using the measured water temperature and total phosphorous. The circulation patterns, water temperature, and water exchange conditions between sub-lakes were simulated under two conditions: (1) the present condition, in which the lake group is isolated from the Yangtze River; and (2) the future condition, with a propos...

  6. Contribution of River Mouth Reach to Sediment Load of the Yangtze River

    Directory of Open Access Journals (Sweden)

    C. Wang

    2015-01-01

    Full Text Available This paper examined the sediment gain and loss in the river mouth reach of the Yangtze River by considering sediment load from the local tributaries, erosion/accretion of the river course, impacts of sand mining, and water extraction. A quantitative estimation of the contribution of the river mouth reach to the sediment load of the Yangtze River was conducted before and after impoundment of the Three Gorges Dam (TGD in 2003. The results showed that a net sediment load loss of 1.78 million ton/yr (Mt/yr occurred from 1965 to 2002 in the study area. The contribution of this reach to the sediment discharge into the sea is not as high as what was expected before the TGD. With impoundment of the TGD, channel deposition (29.90 Mt/yr and a net sediment loss of 30.89 Mt/yr occurred in the river mouth reach from 2003 to 2012. The river mouth reach has acted as a sink but not a source of sediment since impoundment of the TGD, which has exacerbated the decrease in sediment load. Technologies should be advanced to measure changes in river channel morphology, as well as in water and sediment discharges at the river mouth reach.

  7. Sediment dynamics of turbidity maximum in Changjiang River mouth in dry season

    Institute of Scientific and Technical Information of China (English)

    Jianhua GAO; Yang YANG; Yaping WANG; Shaoming PAN; Rui ZHANG

    2008-01-01

    High-resolution current velocity and sus pended sediment concentration(SSC)data were collected by using an Acoustic Doppler Current Profiler(ADCP)at two anchor stations and a cross-section in the South Channel of the Changiiang River mouth during meso and neap tides on Nov.16,2003.In addition,tidal cycle (13-hour)observation at two stations was carried out with traditional methods during the spring tide.Results indi cated that resuspension occurred not only at the flood and ebb maximum,but also in the early phase of ebb in the meso and neap tide.When tidal current transited from high to ebb phase,current speed accelerated.Subse quently,fine-grained sediment with low critical threshold was resuspended and increased concentration.The river mouth area remained in siltation in the meso and neap tidal phase during the observation season,with calculated resuspension flux in the order of magnitude Of 10-4- 10-7 kg·m-2/s.Suspended sediment transport in the South Channel was dominated by freshwater discharge, but the Storks drift,vertical circulation and vertical shear effect due to tidal oscillation also played an important role in resuspension mid associated sediment transport.In contrast,resuspcnsion sediment flux in the spring tide Was larger than that ln meso and neap tide,especially at the ebb maximum and flood maximum.The present study revealed that intensive resuspension corresponded well with the larger current velocity during winter.In addition, the'tidal pumping'effect and tidal gravity circulation were also vital for forming the turbidity maximum in the Changjiang River estuary.

  8. Nitrification and its oxygen consumption along the turbid Changjiang River plume

    Directory of Open Access Journals (Sweden)

    S. S.-Y. Hsiao

    2013-05-01

    Full Text Available Nitrification rates of bulk water (NRb and particle free (NRpf, particle > 3 μm eliminated were determined along the Changjiang River plume in August 2011 by nitrogen isotope tracer technique. Dissolved oxygen (DO, community respiration rate (CR, nutrients, dissolved organic nitrogen, total suspended matter (TSM, particulate organic carbon/nitrogen (POC/PON, acid-leachable iron and manganese on suspended particles and both archaeal and β-proteobacterial amoA abundance on size-fractioned particle (> 3 μm and 0.22–3 μm were measured. The NRb ranged from undetectable up to 4.6 μmol L−1 d−1 peaking at salinity of ~ 29. NRb values were positively correlated with ammonia concentration suggesting the importance of substrate in nitrification. In river mouth and inner plume, NRb was much higher than NRpf indicating nitrifying bacteria is mainly particle-associated, which was supported by amoA gene abundance and regression analysis of TSM and NRb. The estimated oxygen demand of nitrification accounted for 0.4% to 317% of CR. The nitrification oxygen demand is much higher than Redfield model's estimation (23% indicating that oxygen might not be the sole oxidant though DO was sufficient (> 58 μmol kg−1. The excess nitrification oxygen demand showed tendency to occur at lower DO samples accompanying with higher acid-leachable Fe/Mn, which implied reactive Fe3+/Mn4+ may play a role as oxidant in nitrification process. Stoichiometric calculation suggested reactive Fe on particles was even 10-fold the oxidant demand for complete ammonia oxidation along all areas of the plume. The involvement of reactive iron and manganese in nitrification process in oxygenated water further complicated the nitrogen cycling in turbid river plume.

  9. Characteristics of Two General Circulation Patterns During Floods over the Changjiang-Huaihe River Valley

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Characteristics of the atmospheric general circulation during the catastrophic floods over the Changjiang-Huaihe River Valley (CHRV) are investigated. There are two precipitation patterns over China in the CHRV flood years: the CHRV flood-whole country-wet (P1) pattern and the CHRV flood-south (north) side-dry (P2) pattern. The circulation analysis results show that there are obvious differences between the NH 500-hPa geopotential height fields of P1 and P2 precipitation patterns. The establishment of East Asia-Atlantic (EAA) correlation chain (the South China Sea (SCS) high-the Meiyu trough-the Okhotsk Sea high over East Asia) is a critical condition for excessive summer precipitation over the CHRV, while the European blocking high plays an important role in determining the precipitation pattern over China in the CHRV flood years. Besides, the relation between the EAA correlation chain and the sea surface temperature anomaly (SSTA) in the North Pacific is also studied.

  10. ENVIRONMENTAL CHANGE AND ITS IMPACTS ON HUMAN SETTLEMENT IN THE CHANGJIANG RIVER DELTA IN NEOLITHIC AGE

    Institute of Scientific and Technical Information of China (English)

    ZHANG Qiang; LIU Chun-ling; ZHU Cheng; JIANG Tong

    2004-01-01

    Dating data,altitude of Neolithic sites,climatic changes from sedimentary records and previous research results were collected and analyzed to detect possible connections between climatic changes and human activities in the Changjiang River Delta in the Neolithic Age.The results indicated that hydrological changes greatly impacted the human activities in the study region.Low-lying geomorphology made the floods and sea level changes become the important factors affecting human activities,especially the altitude change of human settlements.People usually moved to higher places during the periods characterized by high sea level and frequent floods to escape the negative influences from water body expansion,which resulted in cultural hiatus in certain profiles.However,some higher-altitude settlements were not the results of climatic changes but the results of social factors,such as religious ceremony and social status.Therefore,further research will be necessary for the degree and types of impacts of climatic changes on human activities in the study area at that time.

  11. Quantitatively distinguishing sediments from the Yangtze River and the Yellow River using δEuN-ΣREEs plot

    Institute of Scientific and Technical Information of China (English)

    JIANG FuQing; ZHOU XiaoJing; LI AnChun; LI TieGang

    2009-01-01

    Sediment samples were collected from the lower channel of the Yangtze River and the Yellow River and the contents of rare earth elements (REEs) were measured. In addition, some historical REEs data were collected from published literatures. Based on the δEuN-ΣREEs plot, a clear boundary was found be-tween the sediments from the two rivers. The boundary can be described as an orthogonal polynomial equation by ordinary linear regression with sediments from the Yangtze River located above the curve and sediments from the Yellow River located below the curve. To validate this method, the REEs con-tents of sediments collected from the estuaries of the Yangtze River and the Yellow River were meas-ured. In addition, the REEs data of sediment Core 255 from the Yangtze River and Core YA01 from the Yellow River were collected. Results show that the samples from the Yangtze River estuary and Core 255 almost are above the curve and most samples from the Yellow River estuary and Core YA01 are below the curve in the δEuN-ΣREEs plot. The plot and the regression equation can be used to distin-guish sediments from the Yangtze River and the Yellow River intuitively and quantitatively, and to trace the sediment provenance of the eastern seas of China. The difference between the sediments from two rivers in the δEuN-ΣREEs plot is caused by different mineral compositions and regional climate patterns of the source areas. The relationship between δEuN and ΣREEs is changed little during the transport from the source area to the river, and from river to the sea. Thus the original information on mineral compositions and climate of the source area was preserved.

  12. Quantitatively distinguishing sediments from the Yangtze River and the Yellow River using δEu_N-ΣREEs plot

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Sediment samples were collected from the lower channel of the Yangtze River and the Yellow River and the contents of rare earth elements (REEs) were measured. In addition, some historical REEs data were collected from published literatures. Based on the δEuN-ΣREEs plot, a clear boundary was found be-tween the sediments from the two rivers. The boundary can be described as an orthogonal polynomial equation by ordinary linear regression with sediments from the Yangtze River located above the curve and sediments from the Yellow River located below the curve. To validate this method, the REEs con-tents of sediments collected from the estuaries of the Yangtze River and the Yellow River were meas-ured. In addition, the REEs data of sediment Core 255 from the Yangtze River and Core YA01 from the Yellow River were collected. Results show that the samples from the Yangtze River estuary and Core 255 almost are above the curve and most samples from the Yellow River estuary and Core YA01 are below the curve in the δEuN-ΣREEs plot. The plot and the regression equation can be used to distin-guish sediments from the Yangtze River and the Yellow River intuitively and quantitatively, and to trace the sediment provenance of the eastern seas of China. The difference between the sediments from two rivers in the δEuN-ΣREEs plot is caused by different mineral compositions and regional climate patterns of the source areas. The relationship between δEuN and ΣREEs is changed little during the transport from the source area to the river, and from river to the sea. Thus the original information on mineral compositions and climate of the source area was preserved.

  13. Biogeochemistry of bulk organic matter and biogenic elements in surface sediments of the Yangtze River Estuary and adjacent sea

    International Nuclear Information System (INIS)

    Highlights: • Biogenic elements cycling in the YRE and adjacent sea surface sediments was discussed. • Factors influencing the biogenic elements distributions were examined. • Potential bioavailability of N and P was determined. • Burial fluxes of TOC, BSi, TN and TP were estimated. • Potential nutrient limitation factors were assessed. - Abstract: This study investigated the distribution and roles of total organic carbon (TOC), biogenic silicon (BSi), various forms of nitrogen (N) and phosphorus (P), and the stable carbon isotope (δ13C) in surface sediments of the Yangtze River Estuary (YRE) and adjacent sea. Terrestrial input accounted for 12–63% of total organic matter in the study area. The distribution of biogenic elements was affected by the Changjiang Diluted Water, the Jiangsu Coastal Current, human activities, marine biological processes, and the sediment grain size. Potentially bioavailable N and P accounted for an average 79.6% of the total N (TN) and 31.8% of the total P (TP), respectively. The burial fluxes for TOC, BSi, TN and TP were 39.74–2194.32, 17.34–517.48, 5.02–188.85 and 3.10–62.72 μmol cm−2 yr−1, respectively. The molar ratios of total N/P (1.2–5.0), Si/P (5.0–14.8) and Fe/P (21–61) indicated that much of the P was sequestered in sediments

  14. Experimental investigation on water quality standard of Yangtze River water source heat pump.

    Science.gov (United States)

    Qin, Zenghu; Tong, Mingwei; Kun, Lin

    2012-01-01

    Due to the surface water in the upper reaches of Yangtze River in China containing large amounts of silt and algae, high content of microorganisms and suspended solids, the water in Yangtze River cannot be used for cooling a heat pump directly. In this paper, the possibility of using Yangtze River, which goes through Chongqing, a city in southwest China, as a heat source-sink was investigated. Water temperature and quality of the Yangtze River in the Chongqing area were analyzed and the performance of water source heat pump units in different sediment concentrations, turbidity and algae material conditions were tested experimentally, and the water quality standards, in particular surface water conditions, in the Yangtze River region that adapt to energy-efficient heat pumps were also proposed. The experimental results show that the coefficient of performance heat pump falls by 3.73% to the greatest extent, and the fouling resistance of cooling water in the heat exchanger increases up to 25.6% in different water conditions. When the sediment concentration and the turbidity in the river water are no more than 100 g/m3 and 50 NTU respectively, the performance of the heat pump is better, which can be used as a suitable river water quality standard for river water source heat pumps. PMID:22797241

  15. On geo-basis of river regulation-A case study for the middle reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    LIU GuoWei

    2008-01-01

    From the point of view that people have to obey the river's geo-attributes in the river regulation,the definition and the meaning of the geo-attributes of a river are discussed.The geo-basis of the river regulation of the middle reaches of the Yangtze River is expounded in five aspects,including the structural geomorphol-ogy environment of flood storage and discharge,the distribution characteristics of subsidence and the sedimentation areas of Dongting Basin,the history evolution of Jianghan Basin,the function of Jianghan Basin and Dongting Basin as the flood water detention areas of Jingjiang River reach in ancient time,and the geological characteristic of Jingjiang River reach.Based on the geo-attributes of the middle reaches of the Yangtze River,some ideas about the middle reach regulation of the Yangtze River are put forward:to process the interchange between the lakes and diked marsh areas in Dongting Basin,to canal the new river route as the flood di-version channel of Jingjiang River reach with the paleo river,to recover the func-tion of Jianghan Basin as flood detention area of the middle reaches.And we should take into consideration the geo-environment of the whole Yangtze River in the river regulation of middle reaches.

  16. Editorial: Eutrophication and hypoxia and their impacts on the ecosystem of the Changjiang Estuary and adjacent coastal environment

    Science.gov (United States)

    Zhang, Jing; Xiao, Tian; Huang, Daji; Liu, Su Mei; Fang, Jianguang

    2016-02-01

    The Changjiang (Yangtze River) Estuary plays an important role in the land-ocean interactions of East Asia, particularly in regard to the fate of land-derived materials and their impact on marine ecosystems in the Northwest Pacific Ocean. The 12 papers included in this special issue describe results from the MEcoPAM Study, an IMBER-China project, which occurred in 2011-2015. This project used a multi-disciplinary approach to understand ecosystem function of the Changjiang Estuary in response to multiple stressors (i.e. combined external forcings). The results presented here show that human activities in the watersheds have greatly changed the flux and variation of dissolved and particulate materials from the river. Further interactions between the Changjiang Watersheds and the East China Sea can dramatically modify the pathways of biogeochemistry and food web dynamics of the estuary and adjacent coastal environment at seasonal and inter-annual scales.

  17. Impact of the Three Gorges Dam on reproduction of four major Chinese carps species in the middle reaches of the Changjiang River

    Science.gov (United States)

    Li, Mingzheng; Duan, Zhonghua; Gao, Xin; Cao, Wenxuan; Liu, Huanzhang

    2016-09-01

    Silver carp ( Hypophthalmichthys molitrix), bighead carp ( Aristichthys nobilis), grass carp ( Ctenopharyngodon idella), and black carp ( Mylopharyngodon piceus) are the four major Chinese carps and are commercially important aquaculture species in China. Reproduction of these carp has declined since the construction of the Three Gorges Dam (TGD) due to an altered water flow and thermal regime in the Changjiang (Yangtze) River. However, details of the changes in reproduction of the four species are not well understood. To assess the impact of the TGD on reproduction of the four carp, we investigated their eggs and larvae at Yidu City, which is 80 km below the TGD, during 2005-2012. We examined diff erences in larval abundance of the four species in the Jianli section (350 km downstream of the TGD) before (1997-2002) and after (2003-2012) construction of the TGD. Based on these observations, the first spawning date of the four species was delayed a mean of about 25 days after the dam was constructed. Mean egg abundance in the Yidu section of the river was 249 million and mean larval abundance was 464 million, which were significant decreases since the 1980s. Moreover, larval abundance in the Jianli section after the dam was constructed was significantly lower than that before construction (ANCOVA, Priver are very similar to those described in the 1980s, and some spawning grounds exist upstream of the TGD. Large free-flowing stretches upstream of the TGD and the creation of artificially flooded downstream reaches are needed to stimulate spawning and eff ectively conserve these four major Chinese carps species.

  18. An Overview of Coilia ectenes in Jiangsu Section of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    Jinrong DUAN; Hongyan ZHANG; Kai LIU; Dongpo XU; Minying ZHANG; Weigang SHI

    2012-01-01

    Anchovies are migratory fish and adult individuals migrate in group from the sea into the river every year because of reproductive needs. TheYangtze River is the largest river in China, with rich food and fish species, hence, the Yangtze River would be an ideal habitat for growth and reproduction of anchovy. In this pa- per, based on fishing log data of anchovy in Jiangsu section of the Yangtze River, realted analysis was conducted in digital map using statistical software and GIS. From 2008 to 2011, the number of anchovy fishing vessels and fishing days in Jiangsu section remained stable, but the fishing volume and economic profit of single-vessel fluctuated constantly. This study provides references and advices for plan and management of anchovy fishery resource to administrative department.

  19. On geo-basis of river regulation——A case study for the middle reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    From the point of view that people have to obey the river’s geo-attributes in the river regulation, the definition and the meaning of the geo-attributes of a river are discussed. The geo-basis of the river regulation of the middle reaches of the Yangtze River is expounded in five aspects, including the structural geomorphology environment of flood storage and discharge, the distribution characteristics of subsidence and the sedimentation areas of Dongting Basin, the history evolution of Jianghan Basin, the function of Jianghan Basin and Dongting Basin as the flood water detention areas of Jingjiang River reach in ancient time, and the geological characteristic of Jingjiang River reach. Based on the geo-attributes of the middle reaches of the Yangtze River, some ideas about the middle reach regulation of the Yangtze River are put forward: to process the interchange between the lakes and diked marsh areas in Dongting Basin, to canal the new river route as the flood diversion channel of Jingjiang River reach with the paleo river, to recover the function of Jianghan Basin as flood detention area of the middle reaches. And we should take into consideration the geo-environment of the whole Yangtze River in the river regulation of middle reaches.

  20. Intraspecific mitochondrial variations between Rhinogobio typus from the Yellow River and Yangtze River.

    Science.gov (United States)

    Jiang, Likun; Chen, Baohua; Feng, Jianxin; Mahboob, Shahid; Al-Ghanim, Khalid A

    2016-09-01

    The complete mitochondrial genome of the first individual Rhinogobio typus collected from the Yellow River were sequenced and compared with the previously reported complete mitochondrial sequence of Rhinogobio typus from the Yangtze River. The length of their circular mitochondrial genome was determined to be 16 599 and 16 608 bp respectively. The comparison of two mitochondrial genomes revealed 237 base pair substitutions and 17 insertions or deletions (indels), including 182 base pair substitutions and 2 indels in protein-coding region. Phylogenetic tree was constructed based on complete mitogenomes of the two populations and closely related 13 teleost species to assess their phylogenic relationship and evolution. PMID:26260174

  1. Influence of seasonal runoff regulation by the Three Gorges Reservoir on saltwater intrusion in the Changjiang River Estuary

    Science.gov (United States)

    Qiu, Cheng; Zhu, Jian-Rong

    2013-12-01

    The Three Gorges Reservoir (TGR) is the largest water conservancy project in the world. It significantly regulates discharge of the Changjiang River on a seasonal scale. It stores water in autumn and drains it during the following dry season. Although the effects of the TGR on various processes in the river, estuary, and adjacent seas have been studied extensively, the TGR's influence on saltwater intrusion around the estuary and its impacts on vital freshwater reservoirs have not been quantitatively evaluated. In this study, we used a well-validated numerical model to simulate the seasonal-scale saltwater intrusion around the Changjiang Estuary under scenarios with and without the TGR regulation. Results showed that during the autumn season, the TGR advanced the timing of saltwater intrusion and slightly increased its intensity. In contrast, as the TGR supplemented river discharge during the dry season, saltwater intrusion around the freshwater reservoirs was significantly suppressed. Moreover, duration of saline water (salinity>0.45, the standard for drinking water) at the Dongfengxisha, Chenhang, and Qingcaosha Reservoirs was shortened by about 16%, 73.1%, and 48%, respectively. The model results showed that overall, operation of the TGR is basically favorable for reducing the burden of freshwater supplement in the high-populated estuarine region.

  2. Distribution patterns of phytoplankton in the Changjiang River estuary and adjacent waters in spring 2009

    Science.gov (United States)

    Kong, Fanzhou; Xu, Zijun; Yu, Rencheng; Yuan, Yongquan; Zhou, Mingjiang

    2016-09-01

    The Changjiang River estuary and adjacent waters are one of the most notable regions for red tides/harmful algal blooms in China's coastal waters. In this study, phytoplankton samples were collected and analyzed during the outbreak stage of red tides in May 2009. It was found that dinoflagellates, Prorocentrum donghaiense and Karenia mikimotoi, and diatoms, Skeletonema spp. and Paralia sulcata, were the major taxa dominating the phytoplankton community. Cluster analysis, non-metric multidimensional scaling (NMDS) and analysis of similarities (ANOSIM) was conducted on a data matrix including taxa composition and cell abundance of the phytoplankton samples. The analyses categorized the samples into three groups at a similarity level of 30%. Group I was characterized by estuarine diatoms and distributed mainly in the highly turbid estuarine region. Group II, which was dominated by the diatom Skeletonema spp. and represented the red tide of Skeletonema spp., was situated around Group I in the sea area west of 122°50'E. Group III was characterized by a high proportion of dinoflagellates and was found further offshore compared with Groups I and II. Group III was further divided into two subgroups (III-S1 and III-S2) at a similarity level of 40%. Group III-S1 was characterized by the presence of the benthic diatom P. sulcata, representing phytoplankton samples collected either from the bottom or from the sea area affected by upwelling. Group III-S2 was dominated by dinoflagellates and represented red tides formed by P. donghaiense and K. mikimotoi. A gradual change of red-tide causative species was observed from the estuary to the offshore sea area, from diatoms to armored dinoflagellates and then unarmored dinoflagellates. Environmental factors associated with each group, and thus affecting the distribution of phytoplankton and red tides, are discussed.

  3. Eco—environment range in the source regions of the Yangtze and Yellow rivers

    Institute of Scientific and Technical Information of China (English)

    DINGYongjian; YANGJianping; LIUShiyin; CHENRensheng; WANGGenxu; SHENYongping; WANGJian; XIEChangwei; ZHANGShiqing

    2003-01-01

    Based on geographical and hydrological extents delimited ,four principles are identified,as the bases for delineating the ranges of the source regions of the Yangtze and Yellow rivers in the paper,According to the Comprehensive analysis of topographical characteristics,climate conditions,vegetation distribution and hydrological features,the source region rages for eco-environmental study are defined,The eastern boundary point is Dari hydrological station in the upper reach of the Yellow River,The watershed above Dari hydrological station is the source region of the Yellow river which drains an area of 4.49×104 km2, Natural environment is Characterized by the major topographical types of plateau lakes and marshland,gentle landforms,alpine cold semi-arid climated,and steppe and meadow vegetation in the source region of the Yellow River,The eastern boundary point is the convergent site of the Nieqiaqu and the Tongtian River in the upstream of the Yangtze River,The watershed above the convergent site is the source region of the Yangtze River,with a watershed area of 12.24×104 km2.Hills and alpine plain topography,gentel terrain ,alpine cold arid and semi-arid climate,and alpine cold grassland and meadow are natural conditions in the source region of the Yangtze River.

  4. An investigation of enhanced recessions in Poyang Lake: Comparison of Yangtze River and local catchment impacts

    Science.gov (United States)

    Zhang, Qi; Ye, Xu-chun; Werner, Adrian D.; Li, Yun-liang; Yao, Jing; Li, Xiang-hu; Xu, Chong-yu

    2014-09-01

    Changes in lake hydrological regimes and the associated impacts on water supplies and ecosystems are internationally recognized issues. During the past decade, the persistent dryness of Poyang Lake (the largest freshwater lake in China) has caused water supply and irrigation crises for the 12.4 million inhabitants of the region. There is conjecture as to whether this dryness is caused by climate variability and/or human activities. This study examines long-term datasets of catchment inflow and Lake outflow, and employs a physically-based hydrodynamic model to explore catchment and Yangtze River controls on the Lake's hydrology. Lake water levels fell to their lowest during 2001-2010 relative to previous decades. The average Lake size and volume reduced by 154 km2 and 11 × 108 m3 during the same period, compared to those for the preceding period (1970-2000). Model simulations demonstrated that the drainage effect of the Yangtze River was the primary causal factor. Modeling also revealed that, compared to climate variability impacts on the Lake catchment, modifications to Yangtze River flows from the Three Gorges Dam have had a much greater impact on the seasonal (September-October) dryness of the Lake. Yangtze River effects are attenuated in the Lake with distance from the River, but nonetheless propagate some 100 km to the Lake's upstream limit. Proposals to build additional dams in the upper Yangtze River and its tributaries are expected to impose significant challenges for the management of Poyang Lake. Hydraulic engineering to modify the flow regime between the Lake and the Yangtze River would somewhat resolve the seasonal dryness of the Lake, but will likely introduce other issues in terms of water quality and aquatic ecosystem health, requiring considerable further research.

  5. The Inheritance Plight of Yangtze River Chant and Its Rescue and Protection Measures

    Directory of Open Access Journals (Sweden)

    Tingting YAN

    2015-01-01

    Full Text Available “Yangtze River chant” is one of the first group of national non-material cultural heritages. The author has conducted extensive field researches on the inheritance status of Yangtze River chant. Achievement has been made from the application for non-material cultural heritage to the post application era, but there is also a plight. Scientific and practical protection policy should be made to ensure Yangtze River chant can be effectively preserved and inherited. As for problems such as the inheritance mode tends to be single, the inheritance investment is not enough, the evaluation mechanisms is still absent, and the working mechanism needs to be specified, the author has advocated protection measures such as to establish diversified inheritance modes, to improve the evaluation mechanism and to develop a clear division system of right and responsibility, etc.. This article is based on systematic methods, interviews and field researches to explore the internal mechanism of effective inheritance and ecological protection.

  6. Functional Rehabilitation of the "Soil Reservoir" in Degraded Soils to Control Floods in the Yangtze River Watershed

    Institute of Scientific and Technical Information of China (English)

    SHI Xue-Zheng; LIANG Yin; YU Dong-Sheng; PAN Xian-Zhang; E. D. WARNER; WANG Hong-Jie

    2004-01-01

    The reasons for the Yangtze River flood calamity in 1998 are briefly introduced. The authors believe that using a "soil reservoir" concept is an important means to help control flooding of the Yangtze River.A "soil reservoir" has a large potential storage capacity and its water can be rapidly "discharged" into the underground water in a timely fashion. The eroded, infertile soils of the Yangtze River Watershed are currently an obstacle to efficient operation of the "soil reservoir". The storage capacity of this "soil reservoir"has been severely hampered due to intensive soil erosion and the formation of soil crusts. Therefore, possible measures to control floods in the Yangtze River Watershed include: rehabilitating the vegetation to preserve soil and water on the eroded infertile soils, enhancing infiltration of the different soil types, and utilizing the large "soil reservoir" of the upper reaches of the Yangtze River.

  7. Characteristics and Process of Land Use Changes in the Yangtze River Delta, China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    As one of the developing countries China has an arable land per capita far below the world's average level. With a high-density population and the quick development of economy and urbanization, the Yangtze River Delta shows the typical characteristics of land use in developed regions of China, which are: high land reclamation rate and low arable land per capita; intensive land use and high output value; and rapid increasing of construction land area and fast diminishing of arable lands. The analysis indicates that the process of the arable land changes in the Yangtze River Delta could be divided into four different change stages over the past 50 years.

  8. A comparative study of the flux and fate of the Mississippi and Yangtze river sediments

    Science.gov (United States)

    Xu, K.; Yang, S. L.

    2015-03-01

    Large rivers play a key role in delivering water and sediment into the global oceans. Large-river deltas and associated coastlines are important interfaces for material fluxes that have a global impact on marine processes. In this study, we compare water and sediment discharge from Mississippi and Yangtze rivers by assessing: (1) temporal variation under varying climatic and anthropogenic impacts, (2) delta response of the declining sediment discharge, and (3) deltaic lobe switching and Holocene sediment dispersal patterns on the adjacent continental shelves. Dam constructions have decreased both rivers' sediment discharge significantly, leading to shoreline retreat along the coast. The sediment dispersal of the river-dominated Mississippi Delta is localized but for the tide-dominated Yangtze Delta is more diffuse and influenced by longshore currents. Sediment declines and relative sea level rises have led to coastal erosion, endangering the coasts of both rivers.

  9. A comparative study of the flux and fate of the Mississippi and Yangtze river sediments

    OpenAIRE

    Xu, K.; Yang, S. L.

    2015-01-01

    Large rivers play a key role in delivering water and sediment into the global oceans. Large-river deltas and associated coastlines are important interfaces for material fluxes that have a global impact on marine processes. In this study, we compare water and sediment discharge from Mississippi and Yangtze rivers by assessing: (1) temporal variation under varying climatic and anthropogenic impacts, (2) delta response of the declining sediment discharge, and (3) deltaic lobe switching and Holoc...

  10. Estimation of suspended sediment concentrations using Terra MODIS: an example from the Lower Yangtze River, China.

    Science.gov (United States)

    Wang, J-J; Lu, X X

    2010-02-01

    Traditional measurements of suspended sediment concentrations (SSC) through in-situ sampling in rivers are expensive and time-consuming to perform. Thus, these methods cannot provide continuous SSC records. Although remote sensing has been used for SSC estimation, little research has been undertaken on inland rivers, especially for highly turbid rivers like the Yangtze. Previous studies have proposed Landsat TM/ETM+ Band 4 as a spectral SSC indicator for the Yangtze, but its limitation on temporal resolution is insufficient for the study of dynamic changes of sediment. This paper presents a method of estimating SSC of the Yangtze at Jiujiang using time-series satellite data of high temporal resolution Terra MODIS. It was found that differences in water reflectance between Band 2 and Band 5 could provide relatively accurate SSC estimation even when in-situ atmospheric conditions were unknown. After cross-validation, mean absolute relative error (ARE) and relative root mean square error (RRMSE) were relatively low (i.e., 25.5% and 36.5%, respectively). This empirical relationship was successfully applied to the estimation of SSC at Datong in the Lower Yangtze River, although the SSC values were generally underestimated. This study suggests that Terra MODIS could be used to estimate SSC in large turbid rivers, although some influencing factors require further study to improve the accuracy of SSC estimation. PMID:20022078

  11. Impact of Yangtze river water transfer on the water quality of the Lixia river watershed, China.

    Directory of Open Access Journals (Sweden)

    Xiaoxue Ma

    Full Text Available To improve water quality and reduce the negative impacts of sudden inputs of water pollution in the Lixia River watershed, China, a series of experimental water transfers from the Yangtze River to the Lixia River were conducted from 2 December 2006 to 7 January 2007. Water samples were collected every six days at 55 monitoring sites during this period. Eight water parameters (water temperature, pH, dissolved oxygen (DO, chemical oxygen demand (COD, potassium permanganate index (CODMn, ammonia nitrogen (NH4+-N, electrical conductivity (EC, and water transparency (WT were analyzed to determine changes in nutrient concentrations during water transfers. The comprehensive pollution index (Pi and single-factor (Si evaluation methods were applied to evaluate spatio-temporal patterns of water quality during water transfers. Water quality parameters displayed different spatial and temporal distribution patterns within the watershed. Water quality was improved significantly by the water transfers, especially for sites closer to water intake points. The degree of improvement is positively related to rates of transfer inflow and drainage outflow. The effects differed for different water quality parameters at each site and at different water transfer times. There were notable decreases in NH4+-N, DO, COD, and CODMn across the entire watershed. However, positive effects on EC and pH were not observed. It is concluded that freshwater transfers from the Yangtze River can be used as an emergency measure to flush pollutants from the Lixia River watershed. Improved understanding of the effects of water transfers on water quality can help the development and implementation of effective strategies to improve water quality within this watershed.

  12. Research Note:Effects of human activities on the Yangtze River suspended sediment flux into the estuary in the last century

    Directory of Open Access Journals (Sweden)

    S. L. Yang

    2004-01-01

    : riverine sediment flux, human activities, surface erosion, dam, Yangtze (Changjiang River

  13. Investigation of seasonal variability of CDOM fluorescence in the southern Changjiang River Estuary by EEM-PARAFAC

    Institute of Scientific and Technical Information of China (English)

    BAI Ying; SU Rongguo; HAN Xiurong; ZHANG Chuansong; SHI Xiaoyong

    2015-01-01

    The southern Changjiang River Estuary has attracted considerable attention from marine scientists because it is a highly biologically active area and is biogeochemically significant. Moreover, land-ocean interactions strongly impact the estuary, and harmful algal blooms (HABs) frequently occur in the area. In October 2010 and May 2011, water samples of chromophoric dissolved organic matter (CDOM) were collected from the southern Changjiang River Estuary. Parallel factor analysis (PARAFAC) was used to assess the samples’ CDOM composition using excitation-emission matrix (EEM) spectroscopy. Four components were identified: three were humic-like (C1, C2 and C3) and one was protein-like (C4). Analysis based on spatial and seasonal distributions, as well as relationships with salinity, Chla and apparent oxygen utilization (AOU), revealed that terrestrial inputs had the most significant effect on the three humic-like Components C1, C2 and C3 in autumn. In spring, microbial processes and phytoplankton blooms were also important factors that impacted the three components. The protein-like Component C4 had autochthonous and allochthonous origins and likely represented a biologically labile component. CDOM in the southern Changjiang River Estuary was mostly affected by terrestrial inputs. Microbial processes and phytoplankton blooms were also important sources of CDOM, especially in spring. The fluorescence intensities of the four components were significantly higher in spring than in autumn. On average, C1, C2, C3, C4 and the total fluorescence intensity (TFI) in the surface, middle and bottom layers increased by 123%–242%, 105%–195%, 167%–665%, 483%–567% and 184%–245% in spring than in autumn, respectively. This finding corresponded with a Chla concentration that was 16–20 times higher in spring than in autumn and an AOU that was two to four times lower in spring than in autumn. The humification index (HIX) was lower in spring that in autumn, and the

  14. The Effect of Geologic Structures on the Control of Floods in the Middle Yangtze River Valley

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper discusses the role of geologic structures in the occurrence of floods and how to prevent flood in the middle reaches of the Yangtze River, and gives the author's suggestion that the Luoshan Qiakou be expanded and the land reclaimed from Dongting Lake be returned to the lake in compliance with the law of geology.

  15. Analysis on the Evolution of Agricultural Structure about Pan-Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    DAI Jiang; LIU Zhi-ying

    2010-01-01

    Starting from the definition of agricultural structure,this paper firstly analyzes the change of industrial and spatial structure of agriculture of Pan-Yangtze River Delta,then inspects the relationship between the development of economics and the evolution of agricultural structure,an the end it provides policy recommendation about the development and adjustment of agricultural structure for the future.

  16. Biocides in the Yangtze River of China: spatiotemporal distribution, mass load and risk assessment.

    Science.gov (United States)

    Liu, Wang-Rong; Zhao, Jian-Liang; Liu, You-Sheng; Chen, Zhi-Feng; Yang, Yuan-Yuan; Zhang, Qian-Qian; Ying, Guang-Guo

    2015-05-01

    Nineteen biocides were investigated in the Yangtze River to understand their spatiotemporal distribution, mass loads and ecological risks. Fourteen biocides were detected, with the highest concentrations up to 166 ng/L for DEET in surface water, and 54.3 ng/g dry weight (dw) for triclocarban in sediment. The dominant biocides were DEET and methylparaben, with their detection frequencies of 100% in both phases. An estimate of 152 t/y of 14 biocides was carried by the Yangtze River to the East China Sea. The distribution of biocides in the aquatic environments was significantly correlated to Gross Domestic Product (GDP), total phosphorus (TP) and total nitrogen (TN), suggesting dominant input sources from domestic wastewater of the cities along the river. Risk assessment showed high ecological risks posed by carbendazim in both phases and by triclosan in sediment. Therefore, proper measures should be taken to reduce the input of biocides into the river systems. PMID:25697474

  17. Source and flux of POC in a karstic area in the Changjiang River watershed: impacts of reservoirs and extreme drought

    Science.gov (United States)

    Ji, Hongbing; Li, Cai; Ding, Huaijian; Gao, Yang

    2016-06-01

    Isotopes of carbon (C) and nitrogen (N) along with C / N ratios of particulate organic carbon (POC) were used to identify source and transformation of organic carbon in the suspended and surface sediments in a typical karstic watershed (the Wujiang River, an important tributary of the Changjiang River). Isotope data for suspended sediments indicate that POC was mainly derived from phytoplankton and C3-dominated soil with an increased contribution of phytoplankton in sites directly affected by the reservoir. In contrast, the POC in surface sediments was mainly derived from C3- and C4-dominated soil with little reservoir influence. The positive correlations of carbon and nitrogen isotopes between suspended and surface sediments indicated that these two carbon pools are tightly coupled. Our conservative estimation suggests that 1.17 × 1010 g of POC is transported to the Three Gorges Reservoir during the study period in 2013. POC yield in the Wujiang River (0.13 t km-2 yr-1) is much lower than those of large rivers with a high abundance of carbonate minerals. Based on the distribution pattern of POC yield, it is inferred that carbonate minerals (lithology) do not contribute significantly to the riverine POC. The cascade of reservoirs and extreme drought had a significant influence on the POC flux in the Wujiang River.

  18. Human impact on erosion patterns and sediment transport in the Yangtze River

    Science.gov (United States)

    Sun, Xilin; Li, Chang'an; Kuiper, K. F.; Zhang, Zengjie; Gao, Jianhua; Wijbrans, J. R.

    2016-08-01

    Sediment load in rivers is an indicator of erosional processes in the upstream river catchments. Understanding the origin and composition of the sediment load can help to assess the influence of natural processes and human activities on erosion. Tectonic uplift, precipitation and run-off, hill slopes and vegetation can influence erosion in natural systems. Agriculture and deforestation are expected to increase the sediment yield, but dams and reservoirs can trap much of this sediment before it reaches the ocean. Here, we use major element composition and 40Ar/39Ar ages of detrital muscovites to constrain the sediment contribution of various tributaries to sedimentation in the Yangtze delta. The sediment contribution calculated from muscovite data was compared with that estimated from current sediment load data from gauging stations. Muscovite data show that the main contributor to the Yangtze delta sands is the Min River, while the current sediment load suggests that the Jinsha and Jialing rivers are the most important current contributors to delta sediments. We suggest that this difference reflects an "old" and "young" erosion pattern, respectively as medium grained muscovite could be transported much slower than suspended sediment load in the complex river-lake systems of the Yangtze River basin. These two different erosion patterns likely reflect enhanced human activity (deforestation, cultivation, and mining) that increasingly overwhelmed long-time natural factors controls on erosion since ~ 1900 cal years B.P.

  19. Colorful Yarn, Beautiful Picture——The Textile Industry in the Pearl River Delta and the Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    Tang Jintao

    2009-01-01

    @@ At present,because of the global financial crisis,many enterprises are facing the plight of the manufacturing pressure.Especially the textile industry in the Pearl Rivher Delta and Yangtze River Delta,they are struggling for the survival through the great stress.Therefore,it is imperative to restructure and upgrade this industry.

  20. IMPACTS OF THE SOUTH-TO-NORTH WATER DIVERSION PROJECTS (MIDDLE ROUTE)ON THE WATER ENVIRONMENT OF THE MIDDLE AND LOWER REACHES OF THE HANJIANG RIVER

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The Hanjiang River is the most important tributary ofthe Changjiang River,which has alength of1570km.Theconfluence of the river withthe Yangtze Riveris at Wuhancity.Fromthe Danjiangkoutothe Nianpanshanextendsthemiddle reach of the Hanjiang River,whichis240kmlongand represents a forkriver section,havingtributaries suchas the Bei River,the Nan River,the Tangbai River,andothers.The lower reach extents from Nianpanshan to theestuary,stretching over409km.,This stretchis a curvedriver section,havingtributaries su...

  1. The low water-leaving radiances phenomena around the Yangtze River Estuary

    Science.gov (United States)

    He, Xianqiang; Bai, Yan; Mao, Zhihua; Chen, Jianyu

    2009-09-01

    Based on the in-situ data and ocean color remote sensing data of SeaWiFS, we found there was a black water region with the normalized water-leaving radiances less than 0.5 mW/(cm2•μm•sr) at the visible light wavelength. Yangtze River Estuary locates in the East China Sea shelf with shallow water. Affected by the tide mixing and the runoff of the Yangtze River and Qiantang River, the turbidity is very high. Generally, the water-leaving radiance is high in the turbid water because of the large particle scattering. The reason of the occurrence of this black water was analyzed by the inherent optical properties and the ocean color components. The results showed that black water was caused by the relative low values of the suspended particle matter concentration and the back scattering ratio.

  2. Hydrodynamic effects of reconnecting lake group with Yangtze River in China

    Directory of Open Access Journals (Sweden)

    Ling KANG

    2011-12-01

    Full Text Available The hydrodynamic effects of reconnecting a lake group with the Yangtze River were simulated using a three-dimensional hydrodynamic model. The model was calibrated and validated using the measured water temperature and total phosphorous. The circulation patterns, water temperature, and water exchange conditions between sub-lakes were simulated under two conditions: (1 the present condition, in which the lake group is isolated from the Yangtze River; and (2 the future condition, with a proposed improvement in which connecting the lake group with the Yangtze River will allow river water to be diverted into the lake group. The simulation period selected was characterized by extremely high temperature and very little rain. The results show that the cold inflow from the river has a significant effect on the water temperature only near the inlets, and the effect is more obvious in the lower water layers than that in the upper ones. The circulation pattern changes significantly and small-scale vortices only exist in part of the lake regions. The water exchange between sub-lakes is greatly enhanced with the proposed improvement. The water replacement rate increases with water diversion but varies in different sub-lakes. Finally, a new water diversion scheme was proposed to avoid contamination of some lakes in the early stage.

  3. Temporal and Spatial Variations of δ18O along the Main Stem of Yangtze River, China

    International Nuclear Information System (INIS)

    The Yangtze River is the largest river in China, and the third longest in the world. Data on δ2H and δ18O isotopes in the river water provide a very useful tool for interpretation of hydrological processes and hydrological cycles related to climate change and anthropogenic activities in a large scale river basin. Since 2003, 170 water samples have been recovered from the first water campaign and regular samples over one year from four stations have been analyzed for δ2H and δ18O composition. From upstream to downstream, the isotopic composition of 2H and 18O gradually increase. The trendline of the first campaign is situated in the middle of the LMWL and the trendline of isotopic δ2H and δ18O for one year sampling at four regular stations is in good accordance with the LMWL. Water inflow from tributaries joining the main stem of Yangtze River are one of the main reasons for spatial isotopic variations in the river's water. Results revealed that temporal and spatial variations in oxygen and hydrogen isotopes of water samples along the main stem of the Yangtze River are strongly driven by the isotope patterns in regional precipitation. Secondary signals deriving from the influx of evaporatively enriched waters from several major lakes or reservoirs along the system are also apparent. The peak of river water isotopic temporal variations corresponds well to the boundary marking the beginning or end of annual flooding periods at- site. The peaks and valleys of river water temporal isotopic variations may be a good indicator to mark the split in river water between surface and groundwater water influences at a given location for a water year. (author)

  4. Teleconnection between the Indian summer monsoon onset and the Meiyu over the Yangtze River Valley

    Institute of Scientific and Technical Information of China (English)

    LIU YunYun; DING YiHui

    2008-01-01

    Based on the Indian and Chinese precipitation data and the NCEP-NCAR reanalysis circulation data,the relationship between the Indian summer monsoon (ISM) onset and the Meiyu over the Yangtze River Valley has been discussed by the methods of correlation analysis and composite analysis. The results show that the date of ISM onset over Kerala in the southwestern coast of the Indian Peninsula is about two weeks earlier than the beginning of the Meiyu over the Yangtze River Valley. After the outbreak of ISM,the teleconnection mode sets up from the western coast of India via the Bay of Bengal (BOB) to the Yangtze River Valley and southern Japan. It is different both in time and space from the teleconnection mode which is from the northwest of India via the Tibetan Plateau to northern China. The former mode is defined as the "south" teleconnection of the Asian summer monsoon,forming in the period of ISM onset; while the latter mode is called the "north" teleconnection,mainly occurring in the Asian monsoon culminant period. During the process of the "south" teleconnection's formation,the Asian monsoon circulation has experienced a series of important changes: ISM onset,the northward movement of the south Asia high (SAH),the onset vortex occurrence,the eastward extension of the stronger tropical westerly belt,and the northeastward jump of the western Pacific subtropical high(WPSH),etc. Consequently,since ISM sets up over Kerala,the whole Asian continent is covered by the upper SAH after about two weeks,while in the mid- and lower troposphere,a strong wind belt forms from the Arabian Sea via the southern India,BOB and the South China Sea (SCS),then along the western flank of WPSH,to the Yangtze River Valley and southern Japan. With the northward moving of the subtropical jet streams,the upper westerly jet stream and the low level jet have been coupled vertically over east Asia,while the Yangtze River Valley happens to locate in the ascending motion area between the upper jet

  5. Risk Assessment on Dietary Exposure to Aflatoxin B1 in Post-Harvest Peanuts in the Yangtze River Ecological Region

    OpenAIRE

    Xiaoxia Ding; Linxia Wu; Peiwu Li; Zhaowei Zhang; Haiyan Zhou; Yizhen Bai; Xiaomei Chen; Jun Jiang

    2015-01-01

    Based on the 2983 peanut samples from 122 counties in six provinces of China’s Yangtze River ecological region collected between 2009–2014, along with the dietary consumption data in Chinese resident nutrition and health survey reports from 2002 and 2004, dietary aflatoxin exposure and percentiles in the corresponding statistics were calculated by non-parametric probability assessment, Monte Carlo simulation and bootstrap sampling methods. Average climatic conditions in the Yangtze River ecol...

  6. Impacts of forest changes on hydrology: a case study of large watersheds in the upper reach of Yangtze River Basin

    OpenAIRE

    Cui, X; Liu, S; Wei, X.

    2012-01-01

    Quantifying the effects of forest changes on hydrology in large watersheds is important for designing forest or land management and adaptation strategies for watershed ecosystem sustainability. Minjiang River watershed located in the upper reach of the Yangtze River Basin plays a strategic role in environmental protection and economic and social wellbeing for both the watershed and the entire Yangtze Basin. The watershed lies in the transition zone from Sichuan Basin to Qinghai-Tibet Pla...

  7. The Effect of Urban Heat Island on Climate Warming in the Yangtze River Delta Urban Agglomeration in China

    OpenAIRE

    Qunfang Huang; Yuqi Lu

    2015-01-01

    The Yangtze River Delta (YRD) has experienced rapid urbanization and dramatic economic development since 1978 and the Yangtze River Delta urban agglomeration (YRDUA) has been one of the three largest urban agglomerations in China. We present evidence of a significant urban heat island (UHI) effect on climate warming based on an analysis of the impacts of the urbanization rate, urban population, and land use changes on the warming rate of the daily average, minimal (nighttime) and maximal (day...

  8. Changes in the Synechococcus Assemblage Composition at the Surface of the East China Sea Due to Flooding of the Changjiang River.

    Science.gov (United States)

    Chung, Chih-Ching; Gong, Gwo-Ching; Huang, Chin-Yi; Lin, Jer-Young; Lin, Yun-Chi

    2015-10-01

    The aim of this study was to elucidate how flooding of the Changjiang River affects the assemblage composition of phycoerythrin-rich (PE-rich) Synechococcus at the surface of the East China Sea (ECS). During non-flooding summers (e.g., 2009), PE-rich Synechococcus usually thrive at the outer edge of the Changjiang River diluted water coverage (CDW; salinity ≤31 PSU). In the summer of 2010, a severe flood occurred in the Changjiang River basin. The plentiful freshwater injection resulted in the expansion of the CDW over half of the ECS and caused PE-rich cells to show a uniform distribution pattern, with decreased abundance compared with the non-flooding summer. The phylogenetic diversity of 16S rRNA gene sequences indicated that the flooding event also shifted the picoplankton community composition from being dominated by Synechococcus, mainly attributed to the clade II lineage, to various orders of heterotrophic bacteria, including Actinobacteria, Flavobacteria, α-Proteobacteria, and γ-Proteobacteria. As an increasing number of studies have proposed that global warming might result in more frequent floods, combining this perspective with the information obtained from our previous [1] and this studies yield a more comprehensive understanding of the relationship between the composition of the marine Synechococcus assemblage and global environmental changes. PMID:25851446

  9. Characteristics Process of Land Use Changes in the Yangtze River Delta,Chian

    Institute of Scientific and Technical Information of China (English)

    PULIJIE; YANGGUISHAN; 等

    2001-01-01

    As one of the developing countries China has an arable land per capita far below the world's average level.With a high-density population an the quick development of economy and urbaniztion,the Yangtze River Delta shows the typical characteristics of land use in developed regions of China,which are:high land reclamation rate and low arable land per capita;intensive land use and high output value;and rapid increasing of construction land area and fast diminishing of arable land.The analysis indicates that the process of the arable land changes in the Yangtze River Delta could be divided into four different change stages over the past 50 years.

  10. Institutional Arrangements for River Basin Management: A Case Study of Comparison between the United States and China

    Institute of Scientific and Technical Information of China (English)

    ZHOU Gang-yan

    2007-01-01

    This note compares institutional arrangements for water resources management in two river basins, namely, those of the Susquehanna River in the United States and the Yangtze River in China. The Susquehanna River Basin Commission is composed of the US federal government and the three states of New York, Pennsylvania, and Maryland through which the Susquehanna River passes. Under the authority of the Susquehanna River Basin Compact, the Commission deals with water resources problems throughout its vast drainage area. In contrast, the Changjiang(Yangtze River) Water Resources Commission (CWRC) lacks relative effectiveness in mobilizing provincial governments in transboundary water resources management.

  11. Assessment and exploitation of the waterfront resources in the middle and lower reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    WANGChuansheng; LIJianhai; ZHULidong

    2003-01-01

    Waterfront resources are important and special kind of natural resources in the marginal area between land and water.The Yangtze River,the longest river in China,is not only rich in waterfront resources,but also has favorable development conditions with great potentiality.Aided by large-scale underwater topographic map,the major factors of the waterfront resources in the middle and lower reaches of the Yangtze River,such as the stability,the water depth and the natural conditions for port construction,are assessed in this paper rspectively on the basis of the overall investigations.The results show that:(1)the waterfront resources are abundant in the middle and lower reaches of the Yangtze River,but lack of perfectly combined high grade waterfront;(2)there exists and obvious regional difference in the natural quality of the waterfront along the Yangtze;(3)the fore-bank water depth and waterfront stability are the main natural factors related to the waterfront auality in the middle and lower reaches of the Yangtze River;(4)the waterfronts along the Yangtze are mainly used for port,warehouse and industrial pruposes; and (5)the waterfronts near important cities are highly used,especially the high-quality waterfronts.In addition,some suggestions for the development and utilization of the waterfront resources are presented in this paper.

  12. Sorption of a branched nonylphenol and perfluorooctanoic acid on Yangtze River sediments and their model components

    OpenAIRE

    Li, C L; R. Ji; Schaffer, A.; Sequaris, J.M.; Amelung, W.; H. Vereecken; E. Klumpp

    2012-01-01

    Many metabolites of organic surfactants such as nonylphenol (NP) and perfluorooctanoic acid (PFOA) are ubiquitously found in the environment and are toxic if not sorbed on soils and sediments. In this study, we quantified the sorption of the NP isomer with the highest endocrine activity, [4-(1-ethyl-1,3-dimethylpentyl) phenol] (NP111), and that of PFOA on Yangtze River sediments and its model components illite, goethite and natural organic matter. The sorption experiments were performed with ...

  13. Urban Household Carbon Emission and Contributing Factors in the Yangtze River Delta, China

    OpenAIRE

    Xu, Xibao; Tan, Yan; Chen, Shuang; Yang, Guishan; Su, Weizhong

    2015-01-01

    Carbon reduction at the household level is an integral part of carbon mitigation. This study analyses the characteristics, effects, contributing factors and policies for urban household carbon emissions in the Yangtze River Delta of China. Primary data was collected through structured questionnaire surveys in three cities in the region – Nanjing, Ningbo, and Changzhou in 2011. The survey data was first used to estimate the magnitude of household carbon emissions in different urban contexts. I...

  14. A magnetic record of heavy metal pollution in the Yangtze River subaqueous delta

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Chenyin [State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062 (China); Zhang, Weiguo, E-mail: wgzhang@sklec.ecnu.edu.cn [State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062 (China); Ma, Honglei [State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062 (China); Feng, Huan [Department of Earth and Environmental Studies, Montclair State University, NJ 07043 (United States); Lu, Honghua [Department of Geography, College of Resources and Environmental Science, East China Normal University, Shanghai 200241 (China); Dong, Yan [State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062 (China); Institute of Geographic Engineering Technology, School of Geographical Science, Nantong University, Nantong 226007 (China); Yu, Lizhong [State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200062 (China)

    2014-04-01

    The rapid industrial development in the Yangtze River watershed over the last several decades has drawn great attention with respect to heavy metal pollution to the Yangtze River estuary and nearby coastal areas. In this study, a 236 cm long sediment core was retrieved from the Yangtze River subaqueous delta (122°36′ E, 31°00′ N) in 2008 and analyzed for magnetic properties and geochemical compositions to investigate heavy metal pollution history. The activity of {sup 137}Cs peaked at depth 140 cm, with a broad plateau between 120 cm and 140 cm, suggesting an average sedimentation rate of 3.11 cm yr{sup −1} for the upper 140 cm layer. Magnetic susceptibility (χ), saturation isothermal remanent magnetization (SIRM), anhysteretic remanent magnetization (χ{sub ARM}) and heavy metal enrichment factors (EF) all showed an upward increase trend above depth 140 cm, suggesting that increased ferrimagnetic mineral concentration was accompanied by heavy metal enrichment in the sediment. Geochemical and granolumetric analyses showed that sediment sources and particle sizes played minor roles in the variations of magnetic properties. The effect of diagenesis, which can lead to the selective removal of magnetic minerals, was noticeable in the lower part of the core (140–236 cm). Co-variation between magnetic properties (χ, SIRM and χ{sub ARM}) and EF of Cu and Pb suggests that the elevated ferrimagnetic mineral concentration can be used as an indicator of heavy metal pollution in the reconstruction of environmental changes in estuarine and coastal settings. - Highlights: • Magnetic parameters can be used as heavy metal pollution proxy. • Heavy metal contents in the Yangtze River estuary increase since the 1960s. • Heavy metal pollution is largely driven by population growth in the catchment.

  15. Bioanalytical and instrumental analysis of thyroid hormone disrupting compounds in water sources along the Yangtze River

    International Nuclear Information System (INIS)

    Thyroid hormone (TH) agonist and antagonist activities of water sources along the Yangtze River in China were surveyed by a green monkey kidney fibroblast (CV-1) cell-based TH reporter gene assay. Instrumental analysis was conducted to identify the responsible thyroid-active compounds. Instrumentally derived L-3,5,3'-triiodothyronine (T3) equivalents (T3-EQs) and thyroid receptor (TR) antagonist activity equivalents referring to dibutyl phthalate (DBP-EQs) were calculated from the concentrations of individual congeners. The reporter gene assay demonstrated that three out of eleven water sources contained TR agonist activity equivalents (TR-EQs), ranging from 286 to 293 ng T3/L. Anti-thyroid hormone activities were found in all water sources with the TR antagonist activity equivalents referring to DBP (Ant-TR-EQs), ranging from 51.5 to 555.3 μg/L. Comparisons of the equivalents from instrumental and biological assays suggested that high concentrations of DBP and di-2-ethylhexyl phthalate (DEHP) were responsible for the observed TR antagonist activities at some locations along the Yangtze River. - Research highlights: → First of all, we indicated the instrumentally derived L-3,5,3'-triiodothyronine (T3) equivalents (T3-EQs) and thyroid receptor (TR) antagonist activity equivalents referring to DBP (DBP-EQs) for the very first time. → Secondly, high concentrations of DBP and DEHP might be responsible for the observed TR antagonist activities at some locations. → Finally, we found that thyroid receptor (TR) antagonist activities were very common in Yangtze River. More attentions should be paid to the TR antagonist activities and the responsible compounds. - In vitro bioassay responses observed in Yangtze River source water extracts showed great TR antagonist activities, and DBP and DEHP were responsible.

  16. In vitro assessment of thyroid hormone disrupting activities in drinking water sources along the Yangtze River

    International Nuclear Information System (INIS)

    The thyroid hormone disrupting activities of drinking water sources from the lower reaches of Yangtze River were examined using a reporter gene assay based on African green monkey kidney fibroblast (CV-1) cells. None of the eleven tested samples showed thyroid receptor (TR) agonist activity. Nine water samples exhibited TR antagonist activities with the equivalents referring to Di-n-butyl phthalate (DNBP) (TR antagonist activity equivalents, ATR-EQ50s) ranging from 6.92 × 101 to 2.85 × 102 μg DNBP/L. The ATR-EQ50s and TR antagonist equivalent ranges (ATR-EQ30–80 ranges) for TR antagonist activities indicated that the water sample from site WX-8 posed the greatest health risks. The ATR-EQ80s of the water samples ranging from 1.56 × 103 to 6.14 × 103 μg DNBP/L were higher than the NOEC of DNBP. The results from instrumental analysis showed that DNBP might be responsible for the TR antagonist activities in these water samples. Water sources along Yangtze River had thyroid hormone disrupting potential. - Highlights: ► We examined thyroidal activities of drinking water sources at lower reaches of Yangtze River. ► Nine sites showed TR antagonist activities and no site exhibited TR agonist activity. ► ATR-EQ50s and ATR-EQ30–80 ranges showed that the tested water samples had potential risks. ► The drinking water after water treatment processes may pose potential risks to residents. ► DBP, DEHP, NP and OP might contribute to TR antagonist activities in the aquatic environment. - Drinking water sources from the lower reaches of Yangtze River showed thyroid hormone disrupting potential in reporter gene assays.

  17. Risk-Based Prioritization among Air Pollution Control Strategies in the Yangtze River Delta, China

    OpenAIRE

    Fu, Joshua S.; Zhuang, Guoshun; Zhou, Ying; Levy, Jonathan Ian

    2010-01-01

    Background: The Yangtze River Delta (YRD) in China is a densely populated region with recent dramatic increases in energy consumption and atmospheric emissions. Objectives: We studied how different emission sectors influence population exposures and the corresponding health risks, to inform air pollution control strategy design. Methods: We applied the Community Multiscale Air Quality (CMAQ) Modeling System to model the marginal contribution to baseline concentrations from different sectors. ...

  18. A magnetic record of heavy metal pollution in the Yangtze River subaqueous delta

    International Nuclear Information System (INIS)

    The rapid industrial development in the Yangtze River watershed over the last several decades has drawn great attention with respect to heavy metal pollution to the Yangtze River estuary and nearby coastal areas. In this study, a 236 cm long sediment core was retrieved from the Yangtze River subaqueous delta (122°36′ E, 31°00′ N) in 2008 and analyzed for magnetic properties and geochemical compositions to investigate heavy metal pollution history. The activity of 137Cs peaked at depth 140 cm, with a broad plateau between 120 cm and 140 cm, suggesting an average sedimentation rate of 3.11 cm yr−1 for the upper 140 cm layer. Magnetic susceptibility (χ), saturation isothermal remanent magnetization (SIRM), anhysteretic remanent magnetization (χARM) and heavy metal enrichment factors (EF) all showed an upward increase trend above depth 140 cm, suggesting that increased ferrimagnetic mineral concentration was accompanied by heavy metal enrichment in the sediment. Geochemical and granolumetric analyses showed that sediment sources and particle sizes played minor roles in the variations of magnetic properties. The effect of diagenesis, which can lead to the selective removal of magnetic minerals, was noticeable in the lower part of the core (140–236 cm). Co-variation between magnetic properties (χ, SIRM and χARM) and EF of Cu and Pb suggests that the elevated ferrimagnetic mineral concentration can be used as an indicator of heavy metal pollution in the reconstruction of environmental changes in estuarine and coastal settings. - Highlights: • Magnetic parameters can be used as heavy metal pollution proxy. • Heavy metal contents in the Yangtze River estuary increase since the 1960s. • Heavy metal pollution is largely driven by population growth in the catchment

  19. Case study on rehabilitation of a polluted urban water body in Yangtze River Basin.

    Science.gov (United States)

    Wu, Juan; Cheng, Shuiping; Li, Zhu; Guo, Weijie; Zhong, Fei; Yin, Daqiang

    2013-10-01

    In the past three decades, the fast development of economy and urbanization has caused increasingly severe pollutions of urban water bodies in China. Consequently, eutrophication and deterioration of aquatic ecosystem, which is especially significant for aquatic vegetation, inevitably became a pervasive problem across the Yangtze River Basin. To rehabilitate the degraded urban water bodies, vegetation replanting is an important issue to improve water quality and to rehabilitate ecosystem. As a case study, a representative polluted urban river, Nanfeihe River, in Hefei City, Anhui Province, was chosen to be a rehabilitation target. In October 2009 and May 2010, 13 species of indigenous and prevalent macrophytes, including seven species emergent, one species floating leaved, and five species submersed macrophytes, were planted along the bank slopes and in the river. Through 1.5 years' replanting practice, the water quality and biodiversity of the river had been improved. The concentrations of total nitrogen (TN), total phosphorus (TP), and ammonia nitrogen (NH4 (+)-N) declined by 46.0, 39.5, and 60.4 %, respectively. The species of macrophytes increased from 14 to 60, and the biodiversity of phytoplankton rose significantly in the river (p<0.05). The biomasses of zooplankton and benthos were also improved after the vegetation replanting. The study confirmed that vegetation replanting could alleviate the increasing water pollution and rehabilitate the degraded aquatic ecosystem. The case study would be an example for polluted urban waters restoration in the middle-downstream area of Yangtze River Base. PMID:23247519

  20. The role of Lake Dongting in regulating the sediment budget of the Yangtze River

    Directory of Open Access Journals (Sweden)

    Shi-bao Dai

    2005-01-01

    Full Text Available Lake Dongting, the second largest freshwater lake in China and located in the middle reaches of the River Yangtze catchment, was formed at the beginning of the Holocene period by sea level rise and has varied in size with changes in local weather patterns. The sedimentation rate in Lake Dongting during the Holocene is about 50×106 m3 yr-1, or 80×106 t yr-1 (a sand bulk density of 1.6×103 kg m-3, given the sediment deposition rate as 10 mm yr-1 and the average lake size as 5000 km2. By comparing the sediment import and export, it is estimated that the sediment deposition rate of Lake Dongting was 110.6×106 t yr-1 from 1956 to 2003. Siltation and raised embankments reduced the size of the lake and its capacity to accommodate floods. The sediment delivery ratio (SDR of the middle and lower Yangtze is about 0.92 (total sediment output divided by total sediment input given that the total sediment supply into the middle and lower Yangtze is 455.1×106 t yr-1 and the total sediment discharge into the sea is 419×106 t yr-1. Therefore, if it were not for Lake Dongting, the sediment flux at Datong would be 73.6×106 t yr-1 (80×106 t yr-1×0.92 more, an increase of 27% during the Holocene and an increase of 26% to 101.75×106 t yr-1 from 1956 to 2003. Historically, Lake Dongting had a considerable influence in regulating the sediment budget of the Yangtze. However, afforestation and the construction of large dams, such as the Three Gorges Dam, reduced significantly the sediment deposition in Lake Dongting. In 2003, the completion of the Three Gorges Dam and the subsequent impoundment of water reduced the sediment input from the Yangtze and net deposition in Lake Dongting dropped to 25% and 18% of the mean values of the historic records (1956-2003. During the same period, the amount of sediment deposited in Lake Dongting was only 10% of the sediment discharge at Datong. The influence of the sediment deposited in Lake Dongting on the sediment flux to

  1. The impact of global warming on the runoff in the Yangtze River Basin

    Science.gov (United States)

    Chen, Hua; Hu, Kang; Xu, Chongyu; Hou, Yukun

    2016-04-01

    As the largest water system in China, the Yangtze River is important to China. The amount and distribution of water resources are a key impact factor to the ecology protection and the economy development in the Yangtze River basin. In this study, the impact of global warming on the runoff in the Yangtze River basin has been evaluated by coupling the GCMs (Global Climate Models) and a monthly water balance model. In the study hydro-meteorological data from 140 gauges and hydrological data from 20 stations are used. The spatial-temporal changing trends of the runoff, precipitation and temperature are analyzed by using the Mann-Kendall method during the period of 1960-2015. A bias correction method and a statistical downscaling method (MC-SVM, Markov Chain-Support Vector Machine) are used to deal with the temperature and precipitation from a regional climate model and their performances have been evaluated. To simulate the runoff in the basin, the two-parameter monthly water balance model is calibrated and validated in the 20 sub-basins. The CMIP5 projections downscaled from RCM are used as inputs into the water balance model to predict the future possible changes on runoff under global warming. The results will be helpful to maintain the health of the water ecology and the sustainability of water resources utilization in the basin.

  2. Significant relationship between spring AO and the summer rainfall along the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The influence of spring AO on the summer rainfall along the Yangtze River is investigated. The long-term rainfall observations are filtered to remove the low-frequency variations longer than 10 years. The inter-annual components show a high correlation to AO in the last hundred years. The strongest correlation appears for May AO and summer rainfall with a value of ?0.39, significant above the 99% confidence level. Associated with one standard deviation stronger May AO index, the rainfall over the Yangtze River to the southern Japan decreases by about 3%-9%, while, at the same time increases by about 3%-6% in the northern China and far-eastern Russia. The coherent changes in rainfall are significantly related to the East Asian summer jet stream in the upper troposphere. When there is stronger AO in spring, the jet stream tends to move polarward in summer, and leads the rainfall-belt to move northward too. That gives rise to a drier condition in the Yangtze River valley, wetter anomalies in northern China. This signal would be helpful for the summer rainfall prediction in China.

  3. CHANGES OF PAN EVAPORATION IN THE UPPER REACH OF THE YANGTZE RIVER

    Institute of Scientific and Technical Information of China (English)

    RONG Yan-shu; WANG Wen; JIANG Hai-yan

    2011-01-01

    The upper reach of the Yangtze River,4 511 km long from west to east,contains a great amount of water resources of the Yangtze River Basin.This article studies the characteristics of the pan evaporation,the related meteorological variables,and their effects on the pan evaporation,based on the data of the daily pan evaporation(1980-2008)and other meteorological variables (1961-2008).The results show that the linear trend of the pan evaporation has remarkable regional features,i.e.,the decrease trend in the southwest and the increase trend in the northeast of the investigated region,and the Yangtze River is approximately the boundary of these trends.The meteorological variables have different effects on the pan evaporation depending on the fact that they are in the category the thermal variables or the dynamic variables.The thermal meteorological variables(i.e.,air temperature,diurnal temperature range,and sunshine duration)have positive partial correlations with the pan evaporation,while the dynamic ones(air pressure,rainfall,and relateive humidity)have negative correlations with the pan evaporation.The correlation of the wind speed remains to be investigated.

  4. The morphometric variation of islands in the middle and lower Yangtze River: A variational analytical explanation

    Science.gov (United States)

    Liu, Xiaofang; Huang, He Qing; Nanson, Gerald C.

    2016-05-01

    Anabranching rivers are formed of islands of various shapes and this study applies a variational analytical approach to explain the morphology of islands of a particular basic shape. A theoretically modeled anabranching river is developed based on observations from the middle and lower Yangtze River, which alternates between a single channel and a two-channel anabranching reach with islands approximately triangular in planform such that one anabranch is longer than the other. The equilibrium condition of the model river is derived from a variational investigation of basic relationships of flow continuity, channel boundary resistance, bedload transport, and energy conservation in the anabranching river. We demonstrate that when such a system reaches stationary equilibrium the triangular planform of the island is determined by the proportions of water and sediment passing through the two channels. We also show that the shorter straight channel takes a larger proportion of sediment relative to its proportion of water. For the island to take a streamlined morphology, the difference between the proportions of water and sediment discharge entering each channel needs to be as small as possible. When the paired proportions of water and sediment discharge take different values, the streamlined morphologies of the island vary in a wide range. In comparison with the measured morphologies of the five islands located in the middle-lower Yangtze River, the theoretically determined lengths of the islands are remarkably consistent, varying from the corresponding field measurements by a range of <±10%.

  5. Observation and analysis of the diluted water and red tide in the sea off the Changjiang River mouth in middle and late June 2003

    Institute of Scientific and Technical Information of China (English)

    ZHU Jianrong; WANG Jinhui; SHEN Huanting; WU Hui

    2005-01-01

    An interdisciplinary comprehensive survey was conducted in middle and late June 2003 with the Multi- Parameter Environmental Monitoring System YSI6600 and water sample analysis in the sea off the Changjiang River mouth. The Changjiang diluted water (CDW) extended offshore with a bimodal structure during the observation, one extending toward the southeast, the other toward the northeast. The main axis of the CDW extended toward the northeast. A severe red tide with wide spatial extent and brown water color happened. Chlorophyll-a (Chl-a) distribution near the Changjiang River mouth also presented a bimodal structure, and its position and shape were roughly consistent with the extension of the CDW. Water sample analysis indicated that the serious eutrophication produced by the huge amount of nutrient load via the Changjiang River was the main cause of red tide bloom. The dominant algal specie at the most measurement stations was skeletonema costatum. There existed three centers of higher Chl-a concentration, locating at (122.45°E, 31.5°N), (122.4°E, 30.8°N) and (123.25°E, 30.0°N), respectively. The red tide at (122.45°E, 31.5°N) was located in the major modal of CDW and higher turbid seawater, its dominant algal specie was prorocentrum dentatum with density 2.23×106 ind/L. The red tide at (122.4°E, 30.8°N) was located in the second modal of CDW and lower turbid seawater, its dominant algal specie was skeletonema costatum with density 1.0×107 ind/L. The dominant algal specie at (123.25°E, 30.0°N) was Heterocapsa circularisquama horiguchi with density 2.0×106 ind/L, which was found for the first time forming red tide in the sea off the Changjiang River mouth.

  6. LONG-TERM EFFECTS OF THE GEZHOUBA PROJECT ON FLOOD PROPAGATION IN THE YANGTZE RIVER

    Institute of Scientific and Technical Information of China (English)

    Yaohua DONG; Ruilan YIN

    2001-01-01

    Based on hydrographs of "81.7" flood and topographies of 1980 and 1993, a 1-D mathematical model of flood is developed to study the effects of the Gezhouba Project on flood propagation along the Yichang-Jianli river reaches in the Yangtze River. Calculations and analysis show that, after 13 years' operation of the Gezhouba Project, the flood peak stages have been lowered, the flood curves of stage-discharge relationship have been moved, however, the effects on the flood discharges and storages can be neglected relatively.

  7. The Trend and Fluctuation of Historical Floods in the Middle Reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    Wu Yi-jin; William A. Gough; Jiang Tong; Wang Xue-lei; Jin Wei-bin

    2003-01-01

    The middle reaches of the Yangtze River are the worst flood area of the whole basin. To study the variation regulation of the floods in this area over a long historical period assure improvement in predictions of floods in the region. The trend of flood occurred frequency has close relationship with human activities near the river. By using statistics analysis, the fluctuations for the time series of floods since 1525 are studied. The results show that the main cycle of flood variation can be identified obviously the period of 2, 8 and 40 years with exceeding the level of confidence 0.03.

  8. The Trend and Fluctuation of Historical Floods in the Middle Reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    Wu; Yi-jin; William; A.Gough; 等

    2003-01-01

    The middle reaches of the Yangtze River are the worst flood area of the whole basin. To study the variation regulation of the floods in this area over a long historical period assure improvment in predictions of floods in the region.The trend of flood occurred frequency has close relationship with human activities near the river. By using statistics analysis, the fluctuations for the time series of floods since 1525 are studied. The results show that the main cycle of flood variation can be identified obviously the period of 2,8 and 40 years with exceeding the level of confidance 0.03.

  9. Impact of the Three Gorges Dam on the spawning stock and natural reproduction of Chinese sturgeon in Changjiang River, China

    Science.gov (United States)

    Gao, Xin; Lin, Pengcheng; Li, Mingzheng; Duan, Zhonghua; Liu, Huanzhang

    2016-01-01

    Chinese sturgeon (Acipenser sinensis) is the flagship species of the Changjiang River. The migration route of this species is blocked by the first dam, the Gezhou Dam, and its reproduction is affected by the Three Gorges Dam (TGD), one of the largest dams in the world. We studied the impact of the impoundment of the Three Gorges Reservoir (TGR) since 2003 on the spawning stock and the natural reproduction of the Chinese sturgeon by using our monitoring data from 1997 to 2013. Results indicate that TGR impoundment has delayed the first spawning dates of the fish from middle-late October to late November, decreased the amount of spawning activities from twice to only once each year, and significantly reduced egg production. In particular, the fish did not demonstrate any spawning activities in 2013. Therefore, TGR impoundment significantly affects the natural reproduction of the fish downstream of the TGD. The spawning stock size of the fish is also predicted to further decrease in the future, which will lead to a risk of population extinction. Ecological regulations must be imposed on decreasing the water temperature to 20°C before mid-October and increasing water discharge downstream of the TGD in October to induce spawning of the Chinese sturgeon.

  10. Impact of the Three Gorges Dam on the spawning stock and natural reproduction of Chinese sturgeon in Changjiang River, China

    Science.gov (United States)

    Gao, Xin; Lin, Pengcheng; Li, Mingzheng; Duan, Zhonghua; Liu, Huanzhang

    2016-09-01

    Chinese sturgeon ( Acipenser sinensis) is the flagship species of the Changjiang River. The migration route of this species is blocked by the first dam, the Gezhou Dam, and its reproduction is affected by the Three Gorges Dam (TGD), one of the largest dams in the world. We studied the impact of the impoundment of the Three Gorges Reservoir (TGR) since 2003 on the spawning stock and the natural reproduction of the Chinese sturgeon by using our monitoring data from 1997 to 2013. Results indicate that TGR impoundment has delayed the first spawning dates of the fish from middle-late October to late November, decreased the amount of spawning activities from twice to only once each year, and significantly reduced egg production. In particular, the fish did not demonstrate any spawning activities in 2013. Therefore, TGR impoundment significantly affects the natural reproduction of the fish downstream of the TGD. The spawning stock size of the fish is also predicted to further decrease in the future, which will lead to a risk of population extinction. Ecological regulations must be imposed on decreasing the water temperature to 20°C before mid-October and increasing water discharge downstream of the TGD in October to induce spawning of the Chinese sturgeon.

  11. Terrestrial contributions to the aquatic food web in the middle Yangtze River.

    Directory of Open Access Journals (Sweden)

    Jianzhu Wang

    Full Text Available Understanding the carbon sources supporting aquatic consumers in large rivers is essential for the protection of ecological integrity and for wildlife management. The relative importance of terrestrial and algal carbon to the aquatic food webs is still under intensive debate. The Yangtze River is the largest river in China and the third longest river in the world. The completion of the Three Gorges Dam (TGD in 2003 has significantly altered the hydrological regime of the middle Yangtze River, but its immediate impact on carbon sources supporting the river food web is unknown. In this study, potential production sources from riparian and the main river channel, and selected aquatic consumers (invertebrates and fish at an upstream constricted-channel site (Luoqi, a midstream estuarine site (Huanghua and a near dam limnetic site (Maoping of the TGD were collected for stable isotope (δ13C and δ15N and IsoSource analyses. Model estimates indicated that terrestrial plants were the dominant carbon sources supporting the consumer taxa at the three study sites. Algal production appeared to play a supplemental role in supporting consumer production. The contribution from C4 plants was more important than that of C3 plants at the upstream site while C3 plants were the more important carbon source to the consumers at the two impacted sites (Huanghua and Maoping, particularly at the midstream site. There was no trend of increase in the contribution of autochthonous production from the upstream to the downstream sites as the flow rate decreased dramatically along the main river channel due to the construction of TGD. Our findings, along with recent studies in rivers and lakes, are contradictory to studies that demonstrate the importance of algal carbon in the aquatic food web. Differences in system geomorphology, hydrology, habitat heterogeneity, and land use may account for these contradictory findings reported in various studies.

  12. 长江干流主要城市江段微量有机物污染分析%Analysis of Micro Organic Compound Pollution in Major City River Reaches of the Main Stem of the Changjiang River

    Institute of Scientific and Technical Information of China (English)

    王彻华; 彭彪

    2002-01-01

    It has become general for surface waters being polluted by micro organic compounds. In order to know the current pollution situation and the properties of micro organic compounds in the Changjiang River, a test was performed on micro organic compounds in the water, bottom material and fish bodies which were sampled from major city river reaches of the Changjiang River. Based on the test result, researchers described and analyzed the sorts, concentration level and distribution features of micro organic compounds. A comprehensive evaluation was conducted by adopting the method of MEG (Multimedia Environmental Goals). The study indicated that ① the water body of major city river reaches of the Changjiang River has been generally polluted. In the test, totally 12 types with 308 kinds of organic compounds were detected. The main pollutants were paraffins, PAHs and lipids; and ② micro organic pollutant content in fish bodies was generally higher than that in bottom material which is in turn higher than that in water; and ③ pollution is relatively severe in the river reaches of mid-to-large comprehensive industrial cities with fairly great TAS (Total Ambient Severity) of public health and ecological system.

  13. Shrinking of Dongting Lake and its weakening connection with the Yangtze River:Analysis of the impact on flooding

    Institute of Scientific and Technical Information of China (English)

    Chunhong Hu Chunming Fang; Wenhong Cao

    2015-01-01

    abstract In this article, the shrinking of Dongting Lake and its progressively weakening connection with the Yangtze River and their impact on flooding before and after the implementation of the Three Gorges Project are analyzed. In recent decades, human activity combined with natural processes has altered the flow of the middle reach channel of the Yangtze River and interfered with its connection with Dongting Lake. This has resulted in progressively more frequent flooding in the area. This study uses hydrological data to analyze the annual maximum discharge and annual maximum stage development of the middle reach of the Yangtze River and Dongting Lake. In recent decades before the Three Gorges Project became operational in 2003, the annual maximum discharge and the maximum stage recorded in the middle reach of the river downstream of Dongting Lake had increased, a result of the weakening of the flood regulation function of Dongting Lake;the annual maximum stage at Luoshan station (downstream, close to the confluence of the Yangtze River and Dongting Lake) had risen by about 2.0 m during 1955–2005, (1.5 m attributed to annual maximum discharge and 0.5 m to river channel deposition). Observational data recorded after the Three Gorges Project was put into operation in 2003, it can be seen that deposition in the Dongting Lake has nearly ceased and the lake's connection with the Yangtze River is stable. It is evident that the flood regulation function of Dongting Lake will continue, and that during the lifetime of the Three Gorges Project, the flood situation in the middle reach of the Yangtze River and Dongting Lake will remain stable.

  14. Large and meso-α scale characteristics of intense rainfall in the mid- and lower reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Meteorological conditions associated with intense rainfall and great floods over mid- and lower reaches of Yangtze River are studied by analyzing the large-, synopticand meso-tα-scale circulation systems for 1991, 1996 and 1998. It is found that the advance and retreat of subtropical high over the West Pacific, the monsoon moisture surge from the South China Sea, cold air outbreak over mid- and high-latitudes, and the meso- tα scale systems (250-2500 km)from the Tibetan Pleateau as well, are responsible for intense rainfall over the Yangtze River Valley. The persistent and heavy rains and great floods over the Yangtze River Valley occurred when all these four systems are synergetic or in phase lock.``

  15. Study on Nutrient Limitation of Phytoplankton in the Field Experiment of the Yangtze River Estuary in Summer

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    From July 23rd to August 15th, 2001, a field cultivation experiment was carried out to determine the limitation factors of phytoplankton in the Yangtze River estuary and the adjacent areas. The results indicated that the potential limiting nutrient was phosphorus in the Yangtze River diluted water area, nitrogen in the offshore of the Yangtze River estuary and the conversion of phosphorus to nitrogen in the middle area. Iron and silicon were not the potential limiting factors. If there were some kinds of limiting factors in the water, the growth of phytoplankton would be limited obviously. In case of disappearance of the limiting factor, the phytoplankton would grow fast. When the Noctiluca scintiuans bloom occurred, the phytoplankton biomass level was very low in a short time due to the grazing pressure. When the grazing pressure disappeared, the phytoplankton would grow quickly in abundant nutrients condition.

  16. Is ENSO related to 2015 Easter Star Capsized on the Yangtze River of China?

    Science.gov (United States)

    Xie, P.

    2015-12-01

    Natural disasters have profound effects on community security and economic damage of China's Hubei province. In June 1st, 2015, a cruise ship, Easter Star, capsized on Yangtze River in Hubei province with 442 died. What reason gives rise to such strong convection causing ship sunk? Based on the wind disasters of Hubei province happened in 1963-2015, this study analyzes their features bytime-series regression, and correlates them to global El Niño/Southern Oscillation (ENSO) events. The compared results demonstrated that the wind disasters shown an increasing tendency. There are two peaks corresponding to the strongest ENSO peaks during the past 50 years; each peak lasts two-three years. The facts demonstrated an essential linear relation between the ENSO phenomena and wind disasters in Hubei province. 2015 Easter Star capsized happened at current El Niño event in 2014-2015. We also observed that the historical wind disasters appeared in seasonal variation. Over 90% events concentrated in spring and summer; very few events happened in autumn and winter. Moreover, the disasters depend on the geographic conditions. Most disasters concentrated in four zones, named as Xingshan-Baokang, Xuanen, Wufeng-Yichang, Jingzhou-Gongan, in which Xingshan and Changyang are the two most density of zones. Yangtze River provides an air flowing conduct for strong convective winds. It can be concluded that the strong convection causing 2015 Easter Star capsized is related to current global ENSO phenomenon.Keywords: ENSO, wind disaster, time-series regression analysis, Easter Star, Yangtze River, Hubei Province,

  17. Genetic Diversity of Daphnia pulex in the Middle and Lower Reaches of the Yangtze River.

    Directory of Open Access Journals (Sweden)

    Wenping Wang

    Full Text Available Increased human activities and environmental changes may lead to genetic diversity variations of Cladocerans in water. Daphnia pulex are distributed throughout the world and often regarded as a model organism. The 16S rDNA, cytochrome c oxidase subunit I (COI, and 18S genes were used as molecular marks. The genetic diversity and phylogeny of D. pulex obtained from 10 water bodies in the middle and lower reaches of the Yangtze River were studied. For 16S rDNA, COI gene, and 18S gene, the A+T content (65.4%, 58.4%, and 54.6% was significantly higher than the G+C content (34.6%, 41.6% and 45.4%. This result was consistent with higher A and T contents among invertebrates. Based on the genetic distances of 16S rDNA and COI genes, the genetic differences of D. pulex from 10 water bodies located in the middle and lower reaches of the Yangtze River in China was minimal (0%-0.8% for 16S rDNA and 0%-1.5% for COI gene. However, D. pulex evolved into two branches in the phylogenetic trees, which coincided with its geographical distribution. Compared with D. pulex from other countries, the average genetic distance of D. pulex obtained from 10 water bodies in the middle and lower reaches of the Yangtze River reached 9.1%-10.5%, thereby indicating that D. pulex may have evolved into different subspecies.

  18. [Recent Distribution and Sources of Polycyclic Aromatic Hydrocarbons in Surface Soils from Yangtze River Delta].

    Science.gov (United States)

    Li, Jing-ya; Wu, Di; Xu, Yun-song; Li, Xiang-dong; Wang, Xi-long; Zeng, Chao-hua; Fu, Xiao-fang; Liu, Wen-xin

    2016-01-15

    A total of 243 surface soil samples collected from 11 cities in the Yangtze River Delta region were analyzed for the concentrations, spatial distribution, component profiles and emission sources of 29 PAH species. The analytical results indicated the total concentrations of PAHs in Yangtze River Delta fell in the range from 21. 0 ng x g(-1) to 3 578.5 ng x g(-1) with an arithmetic mean and standard deviation of 310.6 ng x g(-1) and 459.1 ng x g(-1), respectively. Our data showed spatial distribution of PAHs concentrations varied greatly in the region. In addition, the contents of PAHs were positively correlated with the total organic carbon fractions in topsoil. The sites with the highest levels of PAHs in the 11 cities studied were located in Suzhou with 759.0 ng x g(-1) +/- 132.9 ng x g(-1) ollowed by the areas of Wuxi and Shanghai, with the total PAHs concentrations of 565. 3 ng x g(-1) +/- 705.5 ng x g(-1) and 349.4 ng g(-1) 220. 1 ng-g(-1) respectively. The profiles of different components pointed to a predominant role of the species with 2-4 rings, and especially for the low molecular weight components with 2-3 rings. A preliminary identification on emission sources of local PAHs was performed by the specific ratios of isomeric species and principal component analysis (PCA). The results designated industrial coal and biomass combustion as the main mixed emission sources of PAHs in surface soils from Yangtze River Delta, and tail gas from transport as another major source in some areas. PMID:27078965

  19. Recent Study of the Changjiang Fault Zone

    Institute of Scientific and Technical Information of China (English)

    Hou Kangming; Zong Kaihong; Guo Jiangning; Xiong Zhen; Li Limei; Zhou Caixia; Jiang Bo

    2009-01-01

    The Changjiang fault zone, also known as the Mufushan-Jiaoshan fault, is a famous fault located at the southern bank of the Changjiang River, near the Nanjing downtown area. Based on multidisciplinary data from shallow artificial seismic explorations in the target detecting area (Nanjing city and the nearby areas), trenching and drilling explorations, classification of Quaternary strata and chronology dating data, this paper provides the most up-to-date results regarding activities of the Changjiang fault zone, including the most recent active time, activity nature, related active parameters, and their relation to seismic activity.

  20. Satellite Data and Hydrological Model to Asses Water Quantity and Quality in the Yangtze River Basin

    Science.gov (United States)

    Mancini, Marco; Li, Jiren; Corbari, Chiara; Zhang, Xingnan; Fang, Yuanhao; Xin, Jinfeng; Zhang, Jianli; Su, Bob

    2014-11-01

    The main objective of the project (ID 10664) is to assess water quantity and quality for the Yangtze River basin through remote sensing data and a distributed hydrological model. Water quantity analyses are assed with a fully distributed hydrological model FEST-EWB which is calibrated assimilating satellite-based Land Surface Temperature (LST) tuning soil and vegetation parameters in each pixel of the domain as a complementary method to the traditional calibration with local Soil Moisture or discharge data. This approach is feasible because the model algorithm uses the land surface temperature as state variable that is directly compared to the satellite LST. The model computes the pixel water balance solving the system of energy and mass balances in terms of a representative equilibrium temperature (RET), that is the land surface temperature that closes the energy balance equation and so governs the fluxes of energy and mass over the basin domain. This equilibrium surface temperature, is comparable to LST as retrieved from operational remote sensing data (MODIS and AATSR) which is used for the calibration of soil and vegetation parameters. FEST-EWB is run for the whole Yangtze River basin at spatial resolution of 0.05° and temporal resolution of 3 hours. Results are provided in terms of hourly evapotranspiration, soil moisture and land surface temperature maps at a pixel resolution and in term of flow duration curves for four river cross sections for the period 2003-2006 where observed data are available. The effects of the Three Gorges dam, the largest hydropower project in the world, is evaluated on the Yangtze flow regime as well as on the two large lakes (Poyang and Dongting) which change considerably their area during the seasons. Satellite data (MERIS) provide in these cases a control of the surface lake dynamic of these water bodies. Cooperation activities between Chinese and European teams is also demonstrated from the use of the FEST-EWB algorithms in the

  1. Heavy Metal Pollution in a Soil-Rice System in the Yangtze River Region of China

    OpenAIRE

    Zhouping Liu; Qiaofen Zhang; Tiqian Han; Yanfei Ding; Junwei Sun; Feijuan Wang; Cheng Zhu

    2015-01-01

    Heavy metals are regarded as toxic trace elements in the environment. Heavy metal pollution in soil or rice grains is of increasing concern. In this study, 101 pairs of soil and rice samples were collected from the major rice-producing areas along the Yangtze River in China. The soil properties and heavy metal (i.e., Cd, Hg, Pb and Cr) concentrations in the soil and rice grains were analyzed to evaluate the heavy metal accumulation characteristics of the soil-rice systems. The results showed ...

  2. Quantitative tolerance values for common stream benthic macroinvertebrates in the Yangtze River Delta, Eastern China.

    Science.gov (United States)

    Qin, Chun-Yan; Zhou, Jin; Cao, Yong; Zhang, Yong; Hughes, Robert M; Wang, Bei-Xin

    2014-09-01

    Aquatic organisms' tolerance to water pollution is widely used to monitor and assess freshwater ecosystem health. Tolerance values (TVs) estimated based on statistical analyses of species-environment relationships are more objective than those assigned by expert opinion. Region-specific TVs are the basis for developing accurate bioassessment metrics particularly in developing countries, where both aquatic biota and their responses to human disturbances have been poorly documented. We used principal component analysis to derive a synthetic gradient for four stressor variables (total nitrogen, total phosphorus, dissolved oxygen, and % silt) based on 286 sampling sites in the Taihu Lake and Qiantang River basins (Yangtze River Delta), China. We used the scores of taxa on the first principal component (PC1), which explained 49.8% of the variance, to estimate the tolerance values (TV(r)) of 163 macroinvertebrates taxa that were collected from at least 20 sites, 81 of which were not included in the Hilsenhoff TV lists (TV(h)) of 1987. All estimates were scaled into the range of 1-10 as in TV(h). Of all the taxa with different TVs, 46.3% of TV(r) were lower and 52.4% were higher than TV(h). TV(r) were significantly (p streams in China, particularly in the Yangtze River Delta. PMID:24865385

  3. Impacts of potential future sea level rise on the North branch of the Changjiang river estuary: Quantifying the saline water intrusion in the dry season

    OpenAIRE

    Kuang, C.P.; Chen, W.; J. Gu; Mao, X.D.; Huang, H.C.

    2013-01-01

    The phenomenon of global sea level rise (SLR) is undeniable; the 4th IPCC report summaries that the average rise rate of global is 1.8 mm/y since 1961. It is widely taken for granted that SLR will have a severe impact on saline water intrusion processes in estuarine areas. In this paper, by using a two-dimensional hydrodynamic model (MIKE21) and SLR scenarios of 0.5m, 1m and 2m, the impacts of potential future SLR on the North Branch of the Changjiang River Estuary are evaluated b...

  4. Seasonality of CO2 in coastal oceans altered by increasing anthropogenic nutrient delivery from large rivers: evidence from the Changjiang-East China Sea system

    Science.gov (United States)

    Chou, W.-C.; Gong, G.-C.; Cai, W.-J.; Tseng, C.-M.

    2013-06-01

    Model studies suggested that human-induced increase in nutrient load may have stimulated primary production and thus enhanced the CO2 uptake capacity in the coastal ocean. In this study, we investigated the seasonal variations of the surface water's partial pressure of CO2 (pCO2sw) in the highly human-impacted Changjiang-East China Sea system between 2008 and 2011. The seasonality of pCO2sw has large spatial variations, with the largest extreme of 170 ± 75 μatm on the inner shelf near the Changjiang Estuary (from 271 ± 55 μatm in summer to 441 ± 51 μatm in autumn) and the weakest extreme of 53 ± 20 μatm on the outer shelf (from 328 ± 9 μatm in winter to 381 ± 18 μatm in summer). During the summer period, stronger stratification and biological production driven by the eutrophic Changjiang plume results in a very low dissolved inorganic carbon (DIC) in surface waters and a very high DIC in bottom waters of the inner shelf, with the latter returning high DIC to the surface water during the mixed period. Interestingly, a comparison with historical data shows that the average pCO2sw on the inner shelf near the Changjiang Estuary has decreased notably during summer, but has increased during autumn and winter from the 1990s to the 2000s. We suggest that this decadal change is associated with recently increased eutrophication. This would increase both the photosynthetic removal of DIC in surface waters and the respiratory release of DIC in bottom waters during summertime, thereby returning more DIC to the surface during the subsequent mixing seasons and/or episodic extreme weather events (e.g., typhoons). Our finding demonstrates that increasing anthropogenic nutrient delivery from a large river may enhance the sequestration capacity of CO2 in summer but may reduce it in autumn and winter. Consequently, the coastal ocean may not necessarily take up more atmospheric CO2 in response to increasing eutrophication, and the net effect largely depends on the relative

  5. Occurrence of estrogenic activities in second-grade surface water and ground water in the Yangtze River Delta, China

    International Nuclear Information System (INIS)

    Second-grade surface water and ground water are considered as the commonly used cleanest water in the Yangtze River Delta, which supplies centralized drinking water and contains rare species. However, some synthetic chemicals with estrogenic disrupting activities are detectable. Estrogenic activities in the second-grade surface water and ground water were surveyed by a green monkey kidney fibroblast (CV-1) cell line based ER reporter gene assay. Qualitative and quantitative analysis were further conducted to identify the responsible compounds. Estrogen receptor (ER) agonist activities were present in 7 out of 16 surface water and all the ground water samples. Huaihe River and Yangtze River posed the highest toxicity potential. The highest equivalent (2.2 ng E2/L) is higher than the predicted no-effect-concentration (PNEC). Bisphenol A (BPA) contributes to greater than 50% of the total derived equivalents in surface water, and the risk potential in this region deserves more attention and further research. -- Highlights: •Estrogenic activities were present in second-grade surface water and ground water. •Most of the detected equivalents were higher than the predicted no-effect-concentration of E2. •ER-EQ20–80 ranges showed that samples in Huaihe River and Yangtze River posed the highest toxicity. •Bisphenol A contributes to most of the instrumentally derived equivalents in surface water. -- Estrogenic activities were observed in second-grade surface water and ground water in Yangtze River Delta, and BPA was the responsible contaminant

  6. Water mass interaction in the confluence zone of the Daning River and the Yangtze River--a driving force for algal growth in the Three Gorges Reservoir.

    Science.gov (United States)

    Holbach, Andreas; Wang, Lijing; Chen, Hao; Hu, Wei; Schleicher, Nina; Zheng, Binghui; Norra, Stefan

    2013-10-01

    Increasing eutrophication and algal bloom events in the Yangtze River Three Gorges Reservoir, China, are widely discussed with regard to changed hydrodynamics and nutrient transport and distribution processes. Insights into water exchange and interaction processes between water masses related to large-scale water level fluctuations in the reservoir are crucial to understand water quality and eutrophication dynamics. Therefore, confluence zones of tributaries with the Yangtze River main stream are dedicated key interfaces. In this study, water quality data were recorded in situ and on-line in varying depths with the MINIBAT towed underwater multi-sensor system in the confluence zone of the Daning River and the Yangtze River close to Wushan City during 1 week in August 2011. Geostatistical evaluation of the water quality data was performed, and results were compared to phosphorus contents of selective water samples. The strongly rising water level throughout the measurement period caused Yangtze River water masses to flow upstream into the tributary and supply their higher nutrient and particulate loads into the tributary water body. Rapid algal growth and sedimentation occurred immediately when hydrodynamic conditions in the confluence zone became more serene again. Consequently, water from the Yangtze River main stream can play a key role in providing nutrients to the algal bloom stricken water bodies of its tributaries. PMID:23247524

  7. Urban growth and environmental impacts in Jing-Jin-Ji, the Yangtze, River Delta and the Pearl River Delta

    Science.gov (United States)

    Haas, Jan; Ban, Yifang

    2014-08-01

    This study investigates land cover changes, magnitude and speed of urbanization and evaluates possible impacts on the environment by the concepts of landscape metrics and ecosystem services in China's three largest and most important urban agglomerations: Jing-Jin-Ji, the Yangtze River Delta and the Pearl River Delta. Based on the classifications of six Landsat TM and HJ-1A/B remotely sensed space-borne optical satellite image mosaics with a superior random forest decision tree ensemble classifier, a total increase in urban land of about 28,000 km2 could be detected alongside a simultaneous decrease in natural land cover classes and cropland. Two urbanization indices describing both speed and magnitude of urbanization were derived and ecosystem services were calculated with a valuation scheme adapted to the Chinese market based on the classification results from 1990 and 2010 for the predominant land cover classes affected by urbanization: forest, cropland, wetlands, water and aquaculture. The speed and relative urban growth in Jing-Jin-Ji was highest, followed by the Yangtze River Delta and Pearl River Delta, resulting in a continuously fragmented landscape and substantial decreases in ecosystem service values of approximately 18.5 billion CNY with coastal wetlands and agriculture being the largest contributors. The results indicate both similarities and differences in urban-regional development trends implicating adverse effects on the natural and rural landscape, not only in the rural-urban fringe, but also in the cities' important hinterlands as a result of rapid urbanization in China.

  8. SPECIES COMPOSITION, HORIZONTAL DISTRIBUTION AND SEASONAL SUCCESSION OF PHYTOPLANKTON IN THE CHANNEL FROM DONGTING LAKE TO THE CHANGJIANG RIVER, CHINA

    Institute of Scientific and Technical Information of China (English)

    魏印心

    2002-01-01

    The species composition, horizontal distribution and seasonal succession of the phytoplankton at five sampling stations in the channel between Dongting Lake and the Changjiang River, China were studied from May 1995 to December 1997. A total of 416 taxa were observed; diatoms comprised the most diversetaxonomic group representing 58.2 % of the total species. The β-mesotrophic indicators were 92 taxa or 22 % of the total, the α-mesotrophic or α,β-eutrophic indicators decreased distinctly to 20 taxa or 4.8 % of the total. The species number and composition of various phyla were approximately similar at Stations 1, 2, 3 and 4, but at Station 5 the number of species was the minimum and the ratio of diatoms to total phytoplankton in the number of species was the highest. In seasonal succession of the phytoplankton species, the number was the highest in May and June, lower in December, January, March and July in the channel. The dominant species were different in different months. The ratio of diatoms speciesnumber to blue green algae and green algae species number diminished gradually from winter to summer and autumn, and then increased gradually from autumn to winter and early spring in the annual cycle. Margalef, Simpson and Shannon-Weaver diversity indices changed in different months, their values were higher in winter, lower in summer. Nygaard's diatoms quotients were lower in winter, then in spring and autumn, higher in summer. These results indicated that the water quality was the best in winter, better in spring and autumn than in summer. The relationship between the structure of the phytoplankton community and the water environmental quality was discussed.``

  9. Intercomparison of CMIP5 simulations of summer precipitation, evaporation, and water vapor transport over Yellow and Yangtze River basins

    Science.gov (United States)

    Bao, Jiawei; Feng, Jinming

    2016-02-01

    Precipitation and other hydrologic variables play important roles in river basins. In this study, summer precipitation, evaporation, and water vapor transport from 16 models that have participated in Coupled Model Intercomparison Project Phase 5 (CMIP5) for the Yellow River basin (a water-limited basin) and the Yangtze River basin (an energy-limited basin) over the period 1986-2005 are analyzed and evaluated. The results suggest that most models tend to overestimate precipitation in the Yellow River basin, whereas precipitation in the Yangtze River basin is generally well simulated. Models that overestimate precipitation in the Yellow River basin also simulate evaporation with large positive biases. For water vapor transport, models and reanalysis data concur that both basins are moisture sinks in summer. In addition, models that strongly overestimate precipitation in the Yellow River basin tend to produce strong water vapor convergence in that region, which is likely to be related to the situation that the western Pacific subtropical high (WPSH) simulated by these models strengthens and advances further westward and northward, resulting in stronger water vapor convergence in the Yellow River basin. Moreover, convective precipitation biases simulated by the models are also partially responsible for their total precipitation biases. Finally, summer precipitation and evaporation are negatively correlated in the Yangtze River basin, whereas the relation between these variables is weak in the Yellow River basin. In both basins, precipitation and water vapor convergence are positively correlated, which is well simulated by all models.

  10. Assessment of Hydrologic Alterations Caused by the Three Gorges Dam in the Middle and Lower Reaches of Yangtze River, China

    OpenAIRE

    Liuzhi Jiang; Xuan Ban; Xuelei Wang; Xiaobin Cai

    2014-01-01

    Hydrologic regime plays a major role in structuring biotic diversity within river ecosystems by controlling key habitat conditions within the river channel and floodplain. Daily flow records from seven hydrological stations and the range of variability approach were utilized to investigate the variability and spatial pattern of the hydrologic alterations induced by the construction of the Three Gorges Dam (TGD) in the middle and lower reaches of the Yangtze River, China. Results show that the...

  11. [Temporal and spatial distribution of red tide in Yangtze River Estuary and adjacent waters].

    Science.gov (United States)

    Liu, Lu-San; Li, Zi-Cheng; Zhou, Juan; Zheng, Bing-Hui; Tang, Jing-Liang

    2011-09-01

    The events of red tide were collected in Yangtze River Estuary and adjacent waters from 1972 to 2009. Based on geographic information system (GIS) analysis on the temporal and spatial distribution of red tide, the distribution map was generated accordingly. The results show: (1) There are three red tide-prone areas, which are outside the Yangtze River estuary and the eastern of Sheshan, Huaniaoshan-Shengshan-Gouqi, Zhoushan and the eastern of Zhujiajian. The red tide occurred 174 times in total, in which there were 25 times covered the area was larger than 1 000 km2. After 2000, the frequency of red tide were significantly increasing; (2) The frequent occurrence of red tide was in May (51% of total occurrence) and June (20% of total occurrence); (3) In all of the red tide plankton, the dominant species were Prorocentrum danghaiense, Skeletonema costatum, Prorocentrum dantatum, Nactiluca scientillans. The red tides caused by these species were 38, 35, 15, 10 times separately. PMID:22165212

  12. Estimating Total Discharge in the Yangtze River Basin Using Satellite-Based Observations

    Directory of Open Access Journals (Sweden)

    Samuel A. Andam‑Akorful

    2013-07-01

    Full Text Available The measurement of total basin discharge along coastal regions is necessary for understanding the hydrological and oceanographic issues related to the water and energy cycles. However, only the observed streamflow (gauge-based observation is used to estimate the total fluxes from the river basin to the ocean, neglecting the portion of discharge that infiltrates to underground and directly discharges into the ocean. Hence, the aim of this study is to assess the total discharge of the Yangtze River (Chang Jiang basin. In this study, we explore the potential response of total discharge to changes in precipitation (from the Tropical Rainfall Measuring Mission—TRMM, evaporation (from four versions of the Global Land Data Assimilation—GLDAS, namely, CLM, Mosaic, Noah and VIC, and water-storage changes (from the Gravity Recovery and Climate Experiment—GRACE by using the terrestrial water budget method. This method has been validated by comparison with the observed streamflow, and shows an agreement with a root mean square error (RMSE of 14.30 mm/month for GRACE-based discharge and 20.98 mm/month for that derived from precipitation minus evaporation (P − E. This improvement of approximately 32% indicates that monthly terrestrial water-storage changes, as estimated by GRACE, cannot be considered negligible over Yangtze basin. The results for the proposed method are more accurate than the results previously reported in the literature.

  13. Design of steel box girder for Taizhou Yangtze River Highway Bridge

    Institute of Scientific and Technical Information of China (English)

    Ding Lei; Shan Hongwei; Zhou Qing; Zheng Benhui

    2011-01-01

    Taizhou Yangtze River Highway Bridge is the first three-pylon two-span suspension bridge in China. The maingirder adopts flat steamline steel closed box girder which has well wind-resistant capability and is technically mature besides beautiful appearance. Straight web plates of the steel box girder in longitudinal direction are proposed in order to ensure the integrity of the steel box girder, and to keep the stress of the steel box girder continuous in the middle pylon,as well as to reduce the gradient of the middle pylon columns. The cross section of the box girder has one box with three cells. Solid-web diaphragm plate with good integrity and high torsional stiffness is adopted. The lifting lugs are utilized in the anchors of suspender cable. In this paper, selection of the cross section of the steel box girder, the general structure design, local structure design and main structure calculation results of Taizhou Yangtze River Bridge are introduced emphatically.

  14. Indoor air quality at five site museums of Yangtze River civilization

    Science.gov (United States)

    Hu, Tafeng; Jia, Wenting; Cao, Junji; Huang, Rujin; Li, Hua; Liu, Suixin; Ma, Tao; Zhu, Yuqing

    2015-12-01

    The Yangtze River civilization, dating back to more than 7 thousand years ago, is one of the most historic culture aggregates in China. For long-term conservation of archaeological artifacts and historical ruins along the Yangtze River, indoor air quality at five site museums were investigated during summer and winter. Unstable microclimate conditions were observed at all five museums. The maximal seasonal variations in temperature and relative humidity were 25.7 °C and 40.0%, respectively. The mass concentration of PM2.5 inside the museums remained at high levels, ranging from 33.9 to 79.6 μg/m3 in winter and from 52.8 to 113.0 μg/m3 in summer. Organic matter (OM) constituted a major fraction (39.3%-53.9% in summer, 22.1%-27.8% in winter) of total PM2.5. The results showed that besides short-term fluctuation and seasonal variation in microclimate conditions, infiltration of gaseous and particulate air pollutants should be of increasing concern at museums in Southern China.

  15. Simulation of temporal and spatial change of N2O emissions in the Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-dong; ZHOU Xiu-ji; CHEN De-liang; OUYANG Zhi-yun; WANG Xiao-ke; Achberger Christine

    2005-01-01

    A biogeochemical model(DNDC) is combined with a plant ecological model to estimate N2O emission from rice paddy fields in the Yangtze River Delta region. The model is driven by local meteorological, soil, and physiological data and is validated for 1999 and 2000 at a site in the region, which showed that the simulated N2O emissions agree fairly well with the observed data. This adds some confidence in the estimated N2O emissions during 1950 and 2000 in the Hangzhou Region. A significant correlation between the N2O emissions and the population for the Hangzhou Region is found, which is due to a combination of increased application of fertilizers and cultivated area.Such a correlation can not be established for the whole Yangtze River Delta region when the data of both urban and rural areas are included. However, when the data from the heavily urbanized areas are excluded, a significant correlation between population and N2O emissions emerges. The results show clearly that both the temporal and the spatial N2O emissions have significant positive relationship with population under traditional farming practice. These results have implications for suitable mitigation options towards a sustainable agriculture and environment in this region.

  16. Application of 2-D sediment model to fluctuating backwater area of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    Yong FAN

    2009-01-01

    Based on the characteristics of backflow,a two-dimensional mathematical model of sediment movement was established.The complexity of the watercourse boundary at the confluence of the main stream and the tributary was dealt with using a boundary-fitting orthogonal coordinate system.The basic equation of the two-dimensional total sediment load model,the numerical calculation format,and key problems associated with using the orthogonal curvilinear coordinate system were discussed.Water and sediment flow in the Chongqing reach of the Yangtze River were simulated.The calculated water level,flow velocity distribution,amount of silting and scouring,and alluvial distribution are found to be in agreement with the measured data,which indicates that the numerical model and calculation method are reasonable.The model can be used for calculation of flow in a relatively complicated river network.

  17. Application of 2-D sediment model to fluctuating backwater area of Yangtze River

    Directory of Open Access Journals (Sweden)

    Yong FAN

    2009-09-01

    Full Text Available Based on the characteristics of backflow, a two-dimensional mathematical model of sediment movement was established. The complexity of the watercourse boundary at the confluence of the main stream and the tributary was dealt with using a boundary-fitting orthogonal coordinate system. The basic equation of the two-dimensional total sediment load model, the numerical calculation format, and key problems associated with using the orthogonal curvilinear coordinate system were discussed. Water and sediment flow in the Chongqing reach of the Yangtze River were simulated. The calculated water level, flow velocity distribution, amount of silting and scouring, and alluvial distribution are found to be in agreement with the measured data, which indicates that the numerical model and calculation method are reasonable. The model can be used for calculation of flow in a relatively complicated river network.

  18. 长江科学院2012年江源科学考察综述及思考%Review and Reflections on CRSRI' s Scientific Investigation in the Source Area of Yangtze River and Lancang River

    Institute of Scientific and Technical Information of China (English)

    郭熙灵

    2012-01-01

    全面介绍了长江科学院2012年对长江和澜沧江源区的河道形态、水文、泥沙、水资源变化及开发利用情况、水土流失现状及成因、水环境水生态状况及地质地貌等开展科学考察的全过程;着重论述了此次科学考察的目的、意义、任务和内容、组织形式;总结了高原上开展大型科学考察在专业及人员遴选、考察方案及技术准备、考察路线选择、身体条件准备、后勤保障等方面以及考察实施过程中的成功经验与存在的不足,提出的诸多建议可为今后开展类似科学考察借鉴.%A scientific investigation in the source area of Yangtze River and Lancang River was carried out by Changjiang( Yangtze) River Scientific Research Institute( CRSRI) in 2012. The investigation covers topics inclusive of river channel morphology, hydrology and sediment, water resource variation and exploitation, current status and causes of soil-water loss, water environment and water, ecology, as well as geology and geomorphology. In the present paper, the whole process of the investigation is presented, with emphasis on the targets, significance, tasks and contents, and organizing pattern as well. Experiences and defects are summarized in aspects of topic and participants selection, investigation scheme and technical preparation, route selection, health condition, and logistic support for large-scale scientific investigation on the plateau. Suggestions are put forward for reference for similar scientific investigations.

  19. Sediment transport following water transfer from Yangtze River to Taihu Basin

    Directory of Open Access Journals (Sweden)

    Zheng GONG

    2011-12-01

    Full Text Available To meet the increasing need of fresh water and to improve the water quality of Taihu Lake, water transfer from the Yangtze River was initiated in 2002. This study was performed to investigate the sediment distribution along the river course following water transfer. A rainfall-runoff model was first built to calculate the runoff of the Taihu Basin in 2003. Then, the flow patterns of river networks were simulated using a one-dimensional river network hydrodynamic model. Based on the boundary conditions of the flow in tributaries of the Wangyu River and the water level in Taihu Lake, a one-dimensional hydrodynamic and sediment transport numerical model of the Wangyu River was built to analyze the influences of the inflow rate of the water transfer and the suspended sediment concentration (SSC of inflow on the sediment transport. The results show that the water transfer inflow rate and SSC of inflow have significant effects on the sediment distribution. The higher the inflow rate or SSC of inflow is, the higher the SSC value is at certain cross-sections along the river course of water transfer. Higher inflow rate and SSC of inflow contribute to higher sediment deposition per kilometer and sediment thickness. It is also concluded that a sharp decrease of the inflow velocity at the entrance of the Wangyu River on the river course of water transfer induces intense sedimentation at the cross-section near the Changshu hydro-junction. With an increasing distance from the Changshu hydro-junction, the sediment deposition and sedimentation thickness decrease gradually along the river course.

  20. Methane and nitrous oxide concentration and emission flux of Yangtze Delta plain river net

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Methane (CH4) and nitrous oxide (N2O) saturation concentration and gas-water interface emission flux in surface water of the Yangtze Delta plain river net were investigated in summer at representative sites including the upper reaches of the Huangpu River and the rivers in the Chongming Island. The results show that the CH4 concentration in river water ranged from 0.30±0.03 to 6.66±0.14 μmol.L-1, and N2O concentration ranged from 13.8±2.33 to 435±116 nmol.L-1. River surface water had a very high satura- tion level of CH4 (from 468±49.0% to 11560±235%) and that of N2O (from 175±29.5% to 4914±1304%). Dissolved oxygen (DO) was the primary factor controlling the CH4 concentration in water. N2O concentration had significant negative correlation with salinity and a significant positive correlation with nitrate (NO3-), nitrite (NO2-), chemical oxygen demand (CODcr) concentration and pH of river water. CH4 and N2O of river water were brought about mainly by methanogenesis and denitrification in river bottom sediment that diffused through sediment-water interface into the water body and then into atmosphere through the gas-water interface. The emission flux of CH4 and N2O at river gas-water interface reached 778±59.8 and 236±63.6 μmol.m-2.h-1, respectively in summer. The river net was a potential source of atmospheric CH4 and N2O because of eutrophication of the water body.

  1. Conservation and Sustainable Exploitation of Forest Ecosystem in Upper Reaches of the Yangtze River -Case Study on Gongga Mountain

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The deforestation on large scale in the upper reaches of Yangtze River has caused serious problems of ecosystem and environment. Restoration of the degenerated forest ecosystems is one of the main research fields. Taking Gongga Mountain as an example, degeneration features and existing problems of forest ecosystems are analyzed in this paper, and the measures are also proposed.

  2. Characteristics of Land Use/Cover and Macroscopic Ecological Changes in the Headwaters of the Yangtze River and of the Yellow River over the Past 30 Years

    Directory of Open Access Journals (Sweden)

    Lulu Liu

    2016-03-01

    Full Text Available Based on land use and land cover (LULC datasets in the late 1970s, the early 1990s, 2004 and 2012, we analyzed characteristics of LULC change in the headwaters of the Yangtze River and Yellow River over the past 30 years contrastively, using the transition matrix and LULC change index. The results showed that, in 2012, the LULC in the headwaters of the Yellow River were different compared to those of the headwaters of the Yangtze River, with more grassland and wet- and marshland. In the past 30 years, the grassland and wet- and marshland increasing at the expense of sand, gobi, and bare land and desert were the main LULC change types in the headwaters of the Yangtze River, with the macro-ecological situation experiencing a process of degeneration, slight melioration, and continuous melioration, in that order. In the headwaters of the Yellow River, severe reduction of grassland coverage, shrinkage of wet- and marshland and the consequential expansion of sand, gobi and bare land were noticed. The macro-ecological situation experienced a process of degeneration, obvious degeneration, and slight melioration, in that order, and the overall change in magnitude was more dramatic than that in the headwaters of the Yangtze River. These different LULC change courses were jointly driven by climate change, grassland-grazing pressure, and the implementation of ecological construction projects.

  3. Holocene shelf-coastal sedimentary systems associated with the Changjiang River:An overview

    Institute of Scientific and Technical Information of China (English)

    GAO Shu

    2013-01-01

    The fate of the terrestrial sediment supplied by rivers is a critical issue for understanding the patterns of Holocene environmental change on continental shelves. The East China Sea is a typical broad continental shelf with abundant sediment supply from large rivers. Here, a variety of sedimentary records were formed during the Holocene period. The sedimentary systems associated with these records have unique charac-teristics in terms of spatial distribution, material composition, deposition rate and the timing of deposition, which are related to active sediment transport processes induced by tides and waves, shelf circulations and sediment gravity flows. The sedimentary records thus formed are high resolution slices, i.e., each record has a temporal resolution of up to 100-10-1 a, but only covers a limited part of the Holocene time. In terms of the spatial distribution, these records are scattered over a large area on the shelf. Further studies of these systems are required to understand the underlying process-product relationships. In particular, the mid-Holocene coastal deposits on the Jiangsu coast, the early to middle Holocene sequences of the Hangzhou Bay, as well as the Holocene mud deposits off the Zhejiang-Fujian coasts, should be investigated in terms of the material supply (from both seabed reworking during the sea level rise event and river discharges), transport-accumulation processes, the sediment sequences and the future evolution of the sedimentary systems. Advanced numerical modeling techniques should be developed to meet the needs of these studies.

  4. Water discharge changes of the Changjiang River downstream Datong during dry season%长江大通-河口段枯季的径流量变化

    Institute of Scientific and Technical Information of China (English)

    张二凤; 陈西庆; 王晓丽

    2003-01-01

    Based on hydrometric data and extensive investigations on water-extracting projects, thispaper presents a preliminary study on water discharge changes between Datong and Xuliujing duringdry season. The natural hydrological processes and human factors that influence the water dischargeare analyzed with the help of GIS method. The investigations indicate that the water-extractingprojects downstream from Datong to Xuliujing had amounted to 64 in number by the end of 2000,with a water-extracting capacity up to 4,626 m3/s averaged in a tidal cycle. The water extraction fromthe Changjiang River has become the most important factor influencing the water dischargedownstream Datong during dry season. The potential magnitude in water discharge changes areestimated based on historical records of water extraction and a water balance model. Thecomputational results were calibrated with the actual data. The future trend in changes of waterdischarge into the sea during dry season was discussed by taking into consideration of newly builthydro-engineering projects. The water extraction downstream Datong in dry season before 2000 had agreat influence on discharges into the sea in the extremely dry year like 1978-1979. It produced a netdecrease of more than 490 m3/s in monthly mean discharges from the Changjiang into the sea. It isexpected that the water extraction will continually increase in the coming decades, especially in dryyears, when the net decrease in monthly mean water discharge will increase to more than 1000 m3/sand will give a far-reaching effect on the changes of water discharge from the Changjiang into thesea.

  5. A physically-based statistical forecast model for the middle-lower reaches of the Yangtze River Valley summer rainfall

    Institute of Scientific and Technical Information of China (English)

    FAN Ke; WANG HuiJun; CHOI YoungJean

    2008-01-01

    A new approach to forecast the middle-lower reaches of the Yangtze River Valley summer rainfall in June-August (JJA) is proposed in this paper. The year-to-year increment of the middle-lower reaches of the Yangtze River Valley is forecasted and hence the summer precipitation could be predicted. In this paper, DY is defined as the difference of a variable between the current year and the preceding year (year-to-year increment). YR denotes the seasonal mean precipitation rate of the middle-lower reaches of the Yangtze River Valley summer rainfall. After analyzing the atmospheric circulation anomalies in winter and spring that were associated with the DY of YR, six key predictors for the DY of YR have been identified. Then the forecast model for the DY of YR is established by using the multi-linear regression method. The predictors for the DY of YR are Antarctic Oscillation, the meridional wind shear between 850hPa and 200hPa over the Indo-Australian region, and so on. The prediction model shows a high skill for the hindcast during 1997-2006, with the average relative root mean square error is at 18%. The model can even reproduce the upward and downward trends of YR during 1984-1998 and 1998-2006. Considering that the current operational forecast models of the summer precipitation over the China region have the average forecast scores at 60%-70% and that the prediction skill for the middle-lower reaches of Yangtze River Valley summer precipitation remains quite limited up to now, thus this new approach to predict the year-to-year increment of the summer precipitation over the Yangtze River Valley (and hence the summer precipitation itself) has the potential to significantly increase the operational forecast skill of the summer precipitation.

  6. Spatial-Temporal Variations of Chlorophyll-a in the Adjacent Sea Area of the Yangtze River Estuary Influenced by Yangtze River Discharge

    Directory of Open Access Journals (Sweden)

    Ying Wang

    2015-05-01

    Full Text Available Carrying abundant nutrition, terrigenous freshwater has a great impact on the spatial and temporal heterogeneity of phytoplankton in coastal waters. The present study analyzed the spatial-temporal variations of Chlorophyll-a (Chl-a concentration under the influence of discharge from the Yangtze River, based on remotely sensed Chl-a concentrations. The study area was initially zoned to quantitatively investigate the spatial variation patterns of Chl-a. Then, the temporal variation of Chl-a in each zone was simulated by a sinusoidal curve model. The results showed that in the inshore waters, the terrigenous discharge was the predominant driving force determining the pattern of Chl-a, which brings the risk of red tide disasters; while in the open sea areas, Chl-a was mainly affected by meteorological factors. Furthermore, a diversity of spatial and temporal variations of Chl-a existed based on the degree of influences from discharge. The diluted water extended from inshore to the east of Jeju Island. This process affected the Chl-a concentration flowing through the area, and had a potential impact on the marine environment. The Chl-a from September to November showed an obvious response to the discharge from July to September with a lag of 1 to 2 months.

  7. Seasonal water storage change of the Yangtze River basin detected by GRACE

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    US-Germany co-sponsered satellite gravimetry mission GRACE (Gravity Recovery And Climate Experiment), launched in March 2002, has been producing monthly time series of Earth gravity models up to degree and order of 120. The GRACE mission consists of two identical satellites flying on an almost polar orbit with an altitude of about 300-500 km and satelite-to-satellite ranging of about 220 km. Thanks to the payloads of space-borne GPS receivers, accelerometers and high-precision K-band satelite-to-satellite ranging mesurements, GRACE gravity models are expected to achieve more than one order of magnitude of improvement over previous models at spatial scales of a few hundred kilometers or larger. Recovery of surface mass re-distribution based on GRACE's time-varying gravity models is applied to studies in solid Earth geophysics, oceanography, climatology and geodesy. At secular time scales, GRACE is expected to provide valuable information on global ice changes, whose variations have profound influences on global climate, and in particular, on sea level changes. At seasonal time scales, GRACE is expected to reveal surface water changes with an accuracy of less than 1 cm, or ocean bottom pressure changes with an accuracy of less than 1 mbar (1 mbar =102 Pa). These surface mass redistribution measurements would impove our understanding of the global and regional mass and energy cycles that are critical to human life. Using 15 GRACE monthly gravity models covering the period from April 2002 to December 2003, this study compares seasonal water storage changes recovered from GRACE data and hydrology models at global and regional scales, with particular focus on the Yangtze River basin of China. Annual amplitude of 3.4 cm of equivalent water height change is found for the Yangtze River basin with maximum in Spring and Autumn, agreeing with two state-of-the-art hydrology models. The differences between GRACE results and model predictions are less than 1-2 cm. We conclude

  8. 1999年长江洪水及几点认识%The 1999 Flood on Changjiang River and Some Thoug hts on It

    Institute of Scientific and Technical Information of China (English)

    WANG; Sheng-fu

    2001-01-01

    Following the basin wide heavy flood on Changjiang River in 1998, a si gnificant flood occurred in 1999. Comparative analysis of both floods in terms of flows and flooding situations shows that both floods had one common feature, that is, the flood stages were fairly high. But they differed greatly at the sa me time, that is, the 1998 flood was a basin wide heavy one while the 1999 flood was a significant local one. At Yichang station there occurred eight flood pea ks in 1998, while in 1999 only three peaks took place. The maximum peak dischar ge at this station in 1999 was 57 600 cubic meters per second, which was smaller than that in 1998. The maximum flood-volume in 30 d of the 1998 flood at this s t ation equaled that in 1954, when an extraordinary heavy flood happened on the River, while the maximum flood-volume in 30 d in 1999 was 25.8 billion cubic me t ers per second smaller than the 1998 one. It is seen that inflow floods from th e upstream Changjiang River (above Yichang) in 1999 were not so big. Comparison of flood volumes in longer period shows that the 1999 flood was relatively conc entrated while the 1998 one had lasted longer duration. Analysis shows that flo oding situations in both years differed significantly in terms of the flood volu mes diverted from river channels due to dyke breaches and collapses, the cases o f polder embankment collapses, the areas of inundated cultivated land and the nu mbers of dangerous events for hydraulic structures. These differences had been resulted from the different properties of both floods and the dyke strengthening efforts made after the 1998 flood. It is seen that flood control engineering c onstructions initiated in the days following the 1998 flood have played an impor tant role in fighting the 1999 flood.

  9. Maintaining healthy rivers and lakes through water diversion from Yangtze River to Taihu lake in Taihu Basin

    Directory of Open Access Journals (Sweden)

    Hao-yun WU

    2008-09-01

    Full Text Available On the basis of the Taihu water resources assessment, an analysis of the importance and rationality of the water diversion from the Yangtze River to Taihu Lake in solving the water problem and establishing a harmonious eco-environment in the Taihu Basin is performed. The water quantity and water quality conjunctive dispatching decision-making support system, which ensures flood control, water supply and eco-aimed dispatching, is built by combining the water diversion with flood control dispatching and strengthening water resources monitoring and forecasting. With the practice and effect assessment, measures such as setting the integrated basin management format, further developing water diversion and improving the hydraulic engineering projects system and water monitoring system are proposed in order to maintain healthy rivers and guarantee the development of the economy and society in the Taihu Basin.

  10. Maintaining healthy rivers and lakes through water diversion from Yangtze River to Taihu Lake in Taihu Basin

    Institute of Scientific and Technical Information of China (English)

    Wu Haoyun; Hu Yan

    2008-01-01

    On the basis of the Taihu water resources assessment, an analysis of the importance and rationality of the water diversion from the Yangtze River to Taihu Lake in solving the water problem and establishing a harmonious eco-environment in the Taihu Basin is performed. The water quantity and watcr quality conjunctive dispatching decision-making support system, which ensures flood control, water supply and eco-aimed dispatching, is built by combining the water diversion with flood control dispatching and strengthening water resources monitoring and forecasting. With the practice and effect assessment, measures such as setting the integrated basin management format, further developing water diversion and improving the hydraulic engineering projects system and water monitoring system are proposed in order to maintain healthy rivers and guarantee the development of the economy and society in the Taihu Basin.

  11. Decadal morphological evolution of the Yangtze Estuary in response to river input changes and estuarine engineering projects

    Science.gov (United States)

    Luan, Hua Long; Ding, Ping Xing; Wang, Zheng Bing; Ge, Jian Zhong; Yang, Shi Lun

    2016-07-01

    The Yangtze Estuary in China has been intensively influenced by human activities including altered river and sediment discharges in its catchment and local engineering projects in the estuary over the past half century. River sediment discharge has significantly decreased since the 1980s because of upstream dam construction and water-soil conservation. We analyzed bathymetric data from the Yangtze Estuary between 1958 and 2010 and divided the entire estuary into two sections: inner estuary and mouth bar area. The deposition and erosion pattern exhibited strong temporal and spatial variations. The inner estuary and mouth bar area underwent different changes. The inner estuary was altered from sedimentation to erosion primarily at an intermediate depth (5-15 m) along with river sediment decline. In contrast, the mouth bar area showed continued accretion throughout the study period. The frequent river floods during the 1990s and simultaneously decreasing river sediment probably induced the peak erosion of the inner estuary in 1986-1997. We conclude that both sediment discharge and river flood events played important roles in the decadal morphological evolution of the Yangtze Estuary. Regarding the dredged sediment, the highest net accretion rate occurred in the North Passage where jetties and groins were constructed to regulate the navigation channel in 1997-2010. In this period, the jetties induced enhanced deposition at the East Hengsha Mudflat and the high accretion rate within the mouth bar area was maintained. The impacts of estuarine engineering projects on morphological change extended beyond their sites.

  12. Population subdivision of the surf clam Mactra chinensis in the East China Sea: Changjiang River outflow is not the sole driver

    Science.gov (United States)

    Ni, Gang; Ni, Lehai; Kong, Lingfeng; Yu, Hong

    2015-01-01

    The northwestern Pacific, characterized by unique tectonic and hydrological settings, has greatly intrigued marine phylogeographers. However, current studies mostly focus on the influence of Pleistocene isolation of sea basins in population structure of species in the region, leaving the contribution of other factors (such as freshwater outflow and environmental gradients) largely unexploited. Here we shed light on the question by investigating phylogeography of the surf clam Mactra chinensis in the East China Sea (ECS). Genetic information was acquired from 501 specimens collected from its main distribution in the region, represented by mitochondrial cytochrome oxidase I (COI) and nine polymorphic microsatellite loci. A shallow and star-like phylogeny was revealed for all COI haplotypes, indicating the origin of populations from a single refugium. Although no divergent lineages existed, population subdivision was detected in both data sets. The most striking pattern was the significant differentiation between populations north and south of a biogeographic boundary—the Changjiang Estuary, suggesting a barrier effect of the freshwater outflow to gene flow. For the northern group, substructure was revealed by COI result as one southernmost population was significant different from other ones. Clear latitude gradations in allele frequencies were revealed by microsatellite analyses, likely influenced by environmental gradient factors such as temperature. Our results demonstrate that genetic subdivision can arise for populations within the ECS despite they have a single origin, and multiple mechanisms including Changjiang River outflow, environmental gradient factors and life-history traits may act in combination in the process. PMID:26468432

  13. Surface Water Pollution in the Yangtze River Delta:Patterns and Countermeasures

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    On the basis of field investigations, observations and experimental data combined with environmental monitoring information, the status and the spatial and temporal patterns of surface water pollution over the past ten years in the Yangtze River Delta have been assessed. The water quality of large rivers is still very good but most of the medium-sized and small rivers have been very seriously polluted. The appearance of black and odorous conditions in rivers in the urban areas has increased due to serious pollution by organic matter with consequent high oxygen demand. Annual increases in N and P concentrations in lakes have accelerated eutrophication. The water quality of rivers in small towns is rapidly deteriorating. The main sources of surface water pollution include industrial and domestic sewage, animal manures, chemical fertilizers in farmland, and polluted sediments in rivers and lakes.Countermeasures against these sources of pollution are presented. Regional laws and regulations for protection of surface waters and their enforcement are urgently required. A regional water environmental management agency should be established. The construction of sewage treatment plants of varying capacity must be accelerated to increase the proportion of sewage treated and to improve the quality of treated effluent. Animal wastes must be recycled effectively and efficiently, and the application rates of fertilizers and manures must be balanced with crop nutrient requirements to prevent diffuse pollution from agriculture.The comprehensive rehabilitation of medium-sized and small rivers should be intensified, and the delimitation and protection of the areas used as sources of drinking water should be strengthened.

  14. CIS-Based Risk Assessment of Debris Flow Disasters in the Upper Reach of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    HAN Yongshun; LIU Hongjiang; ZHONG Dunlun; SU Fenghuan; LI Chaokui

    2007-01-01

    This paper discussed theory and methodologies of debris-flow risk assessment and established an implementation process according to indicators of debris-flow hazard degree, vulnerability, risk degree, etc. Among these methodologies, historical and potential hazard degree was comprehensively considered into hazard assessment and hazard index was presented to indicate the debris-flow hazard degree. Regarding debris-flow vulnerability assessment, its statistical data and calculating procedure were based on the hazard-degree regionalization instead of administrative divisions, which improved the assessing scientificity and precision. These quantitative methodologies integrated with Geography Information System (GIS) were applied to the risk assessment of debris flows in the upper reach of Yangtze River. Its results were in substantial agreement on investigation data and the actual distribution of debris flows, which showed that these principles and methodologies were reasonable and feasible and can provide basis or reference for debris-flow risk assessment and disaster management.

  15. Engineering Strategies on Flood Control in Middle Reach of Yangtze River, China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Flood disaster has been a serious hidden danger since the ancient time. The essential cause for the fact that floods have not been eliminated for hundreds of years is that time-honored strategies do not suit the cases of flood prevention. In the view of geological environmental analyses of flood formation and from the synthesis of experiences gained in flood control in the past hundreds of years, sluggish draining of flood, silt sedimentation in channel and building levee blindly constitute the main cause of intractable flood for a long time in the middle reach of the Yangtze River.Draining away silt and water is the only way to stamping out flood disaster. Opening up artificial waterways for flood diversion, draining away the silt of channel into the polders, and storing the flood water are important engineering measures for the flood control and damage reduction.

  16. Morphological description of the Genus Skeletonema(Bacillariophyceae in Yangtze River Estuary,China

    Directory of Open Access Journals (Sweden)

    WU Bo

    2013-02-01

    Full Text Available We examined the morphology of Skeletonema species occurring in Yangtze River Esturary by the light microscopy (LM and scanning electron microscopy (SEM .Two species,Skeletonema costatum(Greville Cleve and Skeletonema marinoi Sarno et Zingone,were discriminated in the genus Skeletonema.Of S.costatum,cell diameters are 6.3-15.1 μm and pervalvar axes are 7.7-11 μm.In S.marinoi,cell diameters are 4.6-11.2 μm and pervalvar axes are 11.7-12.2 μm. S.costatum is widely distributed in all seasons,while S.marinoi is only occurred in spring.

  17. Hydrodynamic Effect of the Regulation Project of Yangtze River Deepwater Channel Downstream of Nanjing

    Institute of Scientific and Technical Information of China (English)

    杨东利; 窦希萍; 张新周; 罗小峰

    2013-01-01

    A two-dimensional flow numerical model of the tidal reaches, which total length is more than 700 km, is established from Datong to the Yangtze River estuary. The tidal levels, velocities, diversion ratios and dynamic axes before and after the separate regulation of each reach and combined regulation of all reaches are obtained. The comparative analysis shows that the regulation project of a separate reach basically has no impact on velocity distributions and variations of diversion ratios of upper and lower reaches, the variations of dynamic axes are only within the local scope of the project. The regulation project of a separate reach also has less impact on the water level in the lower adjacent reaches, but will make the water levels in the upper reaches rise. After the implementation of the regulation projects for all reaches, the rise of water level in the upstream reaches will have a cumulative impact.

  18. Application of a Sediment Information System to the Three Gorges Project on Yangtze River, China

    Science.gov (United States)

    Cao, Shuyou; Liu, Xingnian; Yang, Kejun; Li, Changzhi

    Based on survey and analysis of a huge number of observed entrance sediment transport data and the research results of physical and numerical modeling of Three Gorges Reservoir on the Yangtze River, a sediment information system was designed. The basis of this system includes spatial data and properties of geographic elements, and various documents involved to the Three Gorges Project (TGP). Database and knowledge base are constructed as the information bank. The running environment is constructed by the general control program to realize requirements about various sediment information. The system chooses the window software as the system software. The techniques of graphical user interfaces and groupware geographic information system are applied in this system. In this phase, the emphases of the system are development of document system, map system, and presentation system. Cross-section system of the TGP was also attached. For further improvement of the system, a prepared interface of decision supporting subsystem is finished.

  19. Dynamic Mechanisms for Evolution of Mountain Rural Settlements and Soil Conservation in Upper Yangtze River Basin

    Institute of Scientific and Technical Information of China (English)

    WANG Qing; CHEN Yong

    2007-01-01

    This paper presents the logic relationship between rural settlement reconstruction and soil conservation in the Upper Yangtze River. Firstly, by introducing the concepts of "flow" and "intercepted flow", we probe into the dynamic mechanism on interaction between ecological and environmental system, and then point out that the "intercepting sites" are physical conditions for establishment of human settlements in mountains. Secondly, by using ecological theories, "flow", "source", and "sink", material cycle and energy flow in mountains have been discussed. Thirdly, according to dissipative structure theory and thermodynamic laws, a hypothesis has been proposed that "entropy flow" is a dynamic force for settlement evolution. Finally, it is argued that a project for soil conservation is set to control and utilize flows so rural settlements can be supported and farmers' life improved.

  20. Business Cost Increases Promote Industrial Restructuring in the Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    江静; 刘志彪

    2007-01-01

    The traditional view holds that China’s comparative advantage lies in low costs,and it is therefore imperative to reduce business costs if China intends to maintain her industrial competitiveness.In the following article,Jiang Jing and Liu Zhibiao present a rather different point of view.They consider it endogenous to increase business costs.Although they may reduce urban competitiveness to a certain extent,increased business costs exert an important"push"effect upon structural adjustment and upgrade and the growth of the regional economy due to the varying degrees of sensitivity of manufacturing industries and producer service industries to business costs.These findings have been corroborated through their analysis of business costs and industrial distribution in Yangtze River Delta cities such as Shanghai,Nanjing, Suzhou,Wuxi and Nantong.

  1. Analysis of the Geomorphology and Environmental Geological Problems of Huzhou on the Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    JIANG Yuehua; WANG Jingdong; YUAN Xueyin; WANG Runhua

    2004-01-01

    Geomorphically, Huzhou, which is on the Yangtze River delta is characterized mainly by plains, with small hills. This paper presents a detailed analysis of the environmental geological hazards both natural and those incurred by human activities in different morphologic units. The authors point out that most of the regional environmental geological problems in the natural geologic-morphologic conditions, such as crustal stability, foundation of soft soil, soil waterlogging and soil erosion, have insignificant effects to the society, or related countermeasures of prevention and control have been adopted. But environmental geological problems incurred by human being's economic activities become more and more severe, for example, water and soil pollution and land subsidence in plain areas resulting from overexploitation of groundwater, and landslides, karst collapses and water and soil loss etc. caused by quarrying in hilly areas.

  2. Emission inventory of anthropogenic air pollutants and VOC species in the Yangtze River Delta region, China

    Directory of Open Access Journals (Sweden)

    C. Huang

    2011-05-01

    Full Text Available The purpose of this study is to develop an emission inventory for major anthropogenic air pollutants and VOC species in the Yangtze River Delta (YRD region for the year 2007. A "bottom-up" methodology was adopted to compile the inventory based on major emission sources in the sixteen cities of this region. Results show that the emissions of SO2, NOx, CO, PM10, PM2.5, VOCs, and NH3 in the YRD region for the year 2007 are 2392 kt, 2293 kt, 6697 kt, 3116 kt, 1511 kt, 2767 kt, and 459 kt, respectively. Ethylene, mp-xylene, o-xylene, toluene, 1,2,4-trimethylbenzene, 2,4-dimethylpentane, ethyl benzene, propylene, 1-pentene, and isoprene are the key species contributing 77 % to the total ozone formation potential (OFP. The spatial distribution of the emissions shows the emissions and OFPs are mainly concentrated in the urban and industrial areas along the Yangtze River and around Hangzhou Bay. The industrial sources, including power plants other fuel combustion facilities, and non-combustion processes contribute about 97 %, 86 %, 89 %, 91 %, and 69 % of the total SO2, NOx, PM10, PM2.5, and VOC emissions. Vehicles take up 12.3 % and 12.4 % of the NOx and VOC emissions, respectively. Regarding OFPs, the chemical industry, domestic use of paint & printing, and gasoline vehicles contribute 38 %, 24 %, and 12 % to the ozone formation in the YRD region.

  3. A new conception on the formation of the first bend of Yangtze River: its relations with Eocene magmatic activities

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Based on field observations, the author proposes a new understanding on the formation of the first bend of the Yangtze River. The relationship between the formation of the first bend of the Yangtze River and Eocene magmatic activity is expounded, suggesting that the first bend of the Yangtze River is the result from choking of the strong magmatic activity in Eocene. As a result, the upstream became a natural reservoir, whose riverside between Mt. Yulong and Mt. Haba was burst,guiding Jinshajiang River running eastward. At the same time, the drastic uplift of the Qinghai-Tibet Plateau led to the deep dissection of the river cut down the channel, resulting in the formation of the Tiger Leaping Gorge. The magnitude of uplift in the study area (located in the eastern of the Tibetan Plateau) is calculated. Taking Mt. Yulong as a base, the magnitude of lift is 3,300 m from Eocene to Pliocene, adding 700 m since Pleistocene, totaling up to 4,000 m or so.

  4. The effect of dams on phosphorus in the middle and lower Yangtze river

    Science.gov (United States)

    Zhou, Jianjun; Zhang, Man; Lu, Pingyu

    2013-06-01

    We investigated the effect of the Three Gorges Project and other dams on the load of phosphorus (P) to the middle and lower Yangtze River (MLY) and discussed the alteration of P on the ecosystem of the MLY. We collected data for continuous flow and sediment over the past 60 years and observed the concentrations of total P (TP) and particulate P (PP) in the pool reaches of the Three Gorges Reservoir (TGR), both before and after the impoundment in 2003. As a result, we obtained highly positive correlations between P and sediment and revealed two changes that were caused by the impoundments: (1) the sediment load to the MLY decreases by 91% and the river becomes almost clear; and (2) the loads of TP and PP to the MLY are sequestered by 77% and 83.5% annually and 75% and 92% in dry seasons, respectively. Because P was the limiting nutrient for bioactivity in the MLY before 2003, such significant reductions, along with the many other consequences of the dams, will not only further reduce the bioavailability of P but also increase the existing high ratio of nitrogen (N) to P. Therefore, it is quite possible to alter the nutrient regime and reduce the aquatic primary productivity of the MLY. Given that many large dams with huge reservoirs are under construction or planned upstream and elsewhere, studies focused on the long-term effects of sediment and P reduction deserve a high priority for the protection of lowland rivers and aquatic ecosystems.

  5. Ecological risk assessment of heavy metals in sediment in the upper reach of the Yangtze River.

    Science.gov (United States)

    Yi, Yu-Jun; Sun, Jie; Tang, Cai-Hong; Zhang, Shang-Hong

    2016-06-01

    Heavy metal pollution in China's Yangtze River basin has been of high concern. The concentrations of heavy metals (Cr, Cd, Hg, Cu, Zn, Pb, and As) in the sediment were investigated in the upper reaches of the river, China. Sediment quality guidelines (SQGs), an enrichment factor (EF), an index of geo-accumulation (I geo), and potential ecological risk were used to evaluate the extent of contamination from the heavy metal concentrations in the sediment. Among the seven metals, a noticeable degree of pollution was seen only in the case of Cd and Cd posed a considerable ecological risk at some sample sites. The Pearson correlation analysis was implemented to determine the relationships among the heavy metals, and principal component analysis (PCA) was performed to determine the most common pollution sources. The elements As, Cd, Pb, and Zn were grouped together, and the anthropogenic sources of these heavy metals were closely related. The sites with higher Cd concentrations were mainly confined to the river's reach near industrial areas. Controlling the pollution sources will effectively reduce the pollutant concentrations in the sediment. PMID:26903129

  6. Evaluation of artificial neural network techniques for flow forecasting in the River Yangtze, China

    Directory of Open Access Journals (Sweden)

    C. W. Dawson

    2002-01-01

    Full Text Available While engineers have been quantifying rainfall-runoff processes since the mid-19th century, it is only in the last decade that artificial neural network models have been applied to the same task. This paper evaluates two neural networks in this context: the popular multilayer perceptron (MLP, and the radial basis function network (RBF. Using six-hourly rainfall-runoff data for the River Yangtze at Yichang (upstream of the Three Gorges Dam for the period 1991 to 1993, it is shown that both neural network types can simulate river flows beyond the range of the training set. In addition, an evaluation of alternative RBF transfer functions demonstrates that the popular Gaussian function, often used in RBF networks, is not necessarily the ‘best’ function to use for river flow forecasting. Comparisons are also made between these neural networks and conventional statistical techniques; stepwise multiple linear regression, auto regressive moving average models and a zero order forecasting approach. Keywords: Artificial neural network, multilayer perception, radial basis function, flood forecasting

  7. Chemical element transfer of weathering granite regolith in the Three Gorges Dam region of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Clearing up sediment and regolith on the foundation of the dam in the Three Gorges of the Yangtze River in 1999, riverbed were exposed. On the basis of weathering granite regolith sampled from different portions of the valley landforms, by analysing total chemical contents with X rays fluorescent slice and calculating proper value of chemical element transferring ratio and intensity, the transferring law of chemical elements in different portions of the landforms were concluded: 1) In various landforms of the river valley, the process of desilication is not distinct; 2) in weathering granite regolith of riverbed, easy soluble CaO and MgO are relatively enriched whereas A1203 tends to decrease. The enriching rate of Fe203 is the greatest in various landforms of the river valley; 3) in weathering granite regolith of flood-plain, K20 and MgO contents are relatively enriched; 4) the weathering granite regolith of valley slope is a typical north subtropical weathering regolith, and its chemical weathering degree is in the transition phase from early to middle period; and 5) there is an opposite layer where K20 is relatively leaching and Na20 relatively enriching in 6.5 m depth of all weathering granite regolith.

  8. Spatial and Temporal Distribution and Trend of Snow Albedo Changes in the Source Region of the Yangtze River in Last Decade Based on MODIS%基于MODIS的长江源近10年积雪反照率时空分布及动态变化

    Institute of Scientific and Technical Information of China (English)

    吴雪娇; 鲁安新; 王丽红; 张华伟

    2013-01-01

    利用EOS-MODIS卫星的积雪反照率数据和一元线性回归法分析2001~2010年长江源区积雪反照率的分布及变化趋势.结果表明:①长江源区积雪季积雪反照率空间分布差异大.冰川区是积雪反照率高值中心(0.67~0.91),长江源东部地区是低值中心(0.15~0.48).②积雪反照率空间分布四季变化明显,峰值出现在次年1月份.③长江源区近10a积雪季平均积雪反照率在高海拔区和冰川区增大比较显著(0.001 2/a).与积雪面积和积雪季降雪量变化呈显著正相关;而源区夏季各月积雪反照率有明显降低趋势,与夏季温度的变暖趋势呈正反馈关系.%Albedo determines surface absorption capability for the solar radiation and impacts the surface radiation balance. The albedo on snow and ice is higher comparing other surfaces, and the absorption of energy from the sun is little on an ice or snow field. Monitoring and researching snow and ice albedo characteristics and variation are necessary to provide accurate data and the theoretical basis for hydrological process research of snow and ice. EOS-MODIS satellite data of snow albedo (MOD10A1 on Level3)were used in the article to analyze the regional and seasonal distribution of snow albedo, as well as the inter-annual trends in the source region of the Changjiang River from 2001 to 2010 using softwares such as ArcGIS and ENVI. Based on the meteorological data of 3 stations on the source region of the Changjiang River from 2000 to 2010, the basic features of temporal changes of temperature and precipitation were investigated. The results show that: 1) Snow albedo were different with space distribution in the snow season in the source region of the Yangtze River. The snow albedo was high on the northern source region of the Yangtze River and on the southwest of the source region of the Changjiang River with 0.67 to 0.91, respectively, whereas part of the east of the source region of the Changjiang River

  9. Sediment pollution and its effect on fish through food chain in the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    Yujun YI; Zhaoyin WANG; Kang ZHANG; Guoan YU; Xuehua DUAN

    2008-01-01

    Suspended sediment adsorbs pollutants from flowing water in rivers and deposits onto the bed.However,the pollutants accumulated in the river bed sediment may affect the bio-community through food chain for a long period of time.To study the problem the concentration of heavy metals (Cr,Cd,Hg,Cu,Fe,Zn,Pb and As) in water,sediment,and fish/invertebrate were investigated in the middle and lower reaches of the Yangtze River during 2006-2007.The concentrations of heavy metals were 100-10,000 times higher in the sediment than in the water.Benthic invertebrates had relatively high concentrations of heavy metals in their tissues due to their proximity to contaminated sediments.Benthic invertivore fish had moderately high concentrations of heavy metals whereas phytoplanktivore fish,such as the silver carp,accumulated the lowest concentration of heavy metals.The concentrations of Cu,Zn,and Fe were higher than Hg,Pb,Cd,Cr,and As in the tissue samples.The concentration of heavy metals was lower in the river sediments than in the lake sediments.Conversely,the concentration of heavy metals was higher in river water than in lake water.While a pollution event into a water body is often transitory,the effects of the pollutants may be long-lived due to their tendency to be absorbed in the sediments and then released into the food chain.The heavy metals were concentrated in the following order:bottom material > demersal fish and benthic fauna >middle-lower layer fish > upper-middle layer fish > water.

  10. Records of bulk organic matter and plant pigments in sediment of the "red-tide zone" adjacent to the Changjiang River estuary

    Science.gov (United States)

    Kang, Zhenjun; Yu, Rencheng; Kong, Fanzhou; Wang, Yunfeng; Gao, Yan; Chen, Jianhua; Guo, Wei; Zhou, Mingjiang

    2016-09-01

    Cultural eutrophication caused by nutrient over-enrichment in coastal waters will lead to a cascading set of ecosystem changes and deleterious ecological consequences, such as harmful algal blooms (HABs) and hypoxia. During the past two decades since the late 1990s, recurrent large-scale HABs (red tides) and an extensive hypoxic zone have been reported in the coastal waters adjacent to the Changjiang River estuary. To retrieve the history of eutrophication and its associated ecosystem changes, a sediment core was collected from the "red-tide zone" adjacent to the Changjiang River estuary. The core was dated using the 210Pb radioisotope and examined for multiple proxies, including organic carbon (OC), total nitrogen (TN), stable isotopes of C and N, and plant pigments. An apparent up-core increase of OC content was observed after the 1970s, accompanied by a rapid increase of TN. The concurrent enrichment of δ13C and increase of the C/N ratio suggested the accumulation of organic matter derived from marine primary production during this stage. The accumulation of OC after the 1970s well reflected the significant increase of primary production in the red-tide zone and probably the intensification of hypoxia as well. Plant pigments, including chlorophyll a, β-carotene, and diatoxanthin, showed similar patterns of variation to OC throughout the core, which further confirmed the important contribution of microalgae, particularly diatoms, to the deposited organic matter. Based on the variant profiles of the pigments representative of different microalgal groups, the potential changes of the phytoplankton community since the 1970s were discussed.

  11. Seasonal changes in phytoplankton biomass and dominant species in the Changjiang River Estuary and adjacent seas: General trends based on field survey data 1959-2009

    Science.gov (United States)

    Yang, Shu; Han, Xiurong; Zhang, Chuansong; Sun, Baiye; Wang, Xiulin; Shi, Xiaoyong

    2014-12-01

    The characteristics of seasonal variation in phytoplankton biomass and dominant species in the Changjiang River Estuary and adjacent seas were discussed based on field investigation data from 1959 to 2009. The field data from 1981 to 2004 showed that the Chlorophyll- a concentration in surface seawater was between 0.4 and 8.5 μg dm-3. The seasonal changes generally presented a bimodal trend, with the biomass peaks occurring in May and August, and Chlorophyll-a concentration was the lowest in winter. Seasonal biomass changes were mainly controlled by temperature and nutrient levels. From the end of autumn to the next early spring, phytoplankton biomass was mainly influenced by temperature, and in other seasons, nutrient level (including the nutrient supply from the terrestrial runoffs) was the major influence factor. Field investigation data from 1959 to 2009 demonstrated that diatoms were the main phytoplankton in this area, and Skeletonema costatum, Pseudo-nitzschia pungens, Coscinodiscus oculus-iridis, Thalassinoema nitzschioides, Paralia sulcata, Chaetoceros lorenzianus, Chaetoceros curvisetus, and Prorocentrum donghaiense Lu were common dominant species. The seasonal variations in major dominant phytoplankton species presented the following trends: 1) Skeletonema (mainly S. costatum) was dominant throughout the year; and 2) seasonal succession trends were Coscinodiscus (spring) → Chaetoceros (summer and autumn) → Coscinodiscus (winter). The annual dominance of S. costatum was attributed to its environmental eurytopicity and long standing time in surface waters. The seasonal succession of Coscinodiscus and Chaetoceros was associated with the seasonal variation in water stability and nutrient level in this area. On the other hand, long-term field data also indicated obvious interannual variation of phytoplankton biomass and community structure in the Changjiang River Estuary and adjacent seas: average annual phytoplankton biomass and dinoflagellate

  12. Records of bulk organic matter and plant pigments in sediment of the "red-tide zone" adjacent to the Changjiang River estuary

    Science.gov (United States)

    Kang, Zhenjun; Yu, Rencheng; Kong, Fanzhou; Wang, Yunfeng; Gao, Yan; Chen, Jianhua; Guo, Wei; Zhou, Mingjiang

    2016-01-01

    Cultural eutrophication caused by nutrient over-enrichment in coastal waters will lead to a cascading set of ecosystem changes and deleterious ecological consequences, such as harmful algal blooms (HABs) and hypoxia. During the past two decades since the late 1990s, recurrent large-scale HABs (red tides) and an extensive hypoxic zone have been reported in the coastal waters adjacent to the Changjiang River estuary. To retrieve the history of eutrophication and its associated ecosystem changes, a sediment core was collected from the "red-tide zone" adjacent to the Changjiang River estuary. The core was dated using the 210Pb radioisotope and examined for multiple proxies, including organic carbon (OC), total nitrogen (TN), stable isotopes of C and N, and plant pigments. An apparent up-core increase of OC content was observed after the 1970s, accompanied by a rapid increase of TN. The concurrent enrichment of δ13C and increase of the C/N ratio suggested the accumulation of organic matter derived from marine primary production during this stage. The accumulation of OC after the 1970s well reflected the significant increase of primary production in the red-tide zone and probably the intensification of hypoxia as well. Plant pigments, including chlorophyll a, β-carotene, and diatoxanthin, showed similar patterns of variation to OC throughout the core, which further confirmed the important contribution of microalgae, particularly diatoms, to the deposited organic matter. Based on the variant profiles of the pigments representative of different microalgal groups, the potential changes of the phytoplankton community since the 1970s were discussed.

  13. Impact of the Three-Gorges Dam and water transfer project on Changjiang floods

    Science.gov (United States)

    Nakayama, Tadanobu; Shankman, David

    2013-01-01

    Increasing frequency of severe floods on the middle and lower Changjiang (Yangtze) River during the past few decades can be attributed to both abnormal monsoon rainfall and landscape changes that include extensive deforestation affecting river sedimentation, and shrinking lakes and levee construction that reduced the areas available for floodwater storage. The Three-Gorges Dam (TGD) and the South-to-North Water Transfer Project (SNWTP) will also affect frequency and intensity of severe floods in the Poyang Lake region of the middle Changjiang. Process-based National Integrated Catchment-based Eco-hydrology (NICE) model predicts that the TGD will increase flood risk during the early summer monsoon against the original justifications for building the dam, relating to complex river-lake-groundwater interactions. Several scenarios predict that morphological change will increase flood risk around the lake. This indicates the importance of managing both flood discharge and sediment deposition for the entire basin. Further, the authors assessed the impact of sand mining in the lake after its prohibition on the Changjiang, and clarified that alternative scenario of sand mining in lakes currently disconnected from the mainstream would reduce the flood risk to a greater extent than intensive dredging along junction channel. Because dry biomasses simulated by the model were linearly related to the Time-Integrated Normalized Difference Vegetation Index (TINDVI) estimated from satellite images, its decadal gradient during 1982-1999 showed a spatially heterogeneous distribution and generally decreasing trends beside the lakes, indicating that the increases in lake reclamation and the resultant decrease in rice productivity are closely related to the hydrologic changes. This integrated approach could help to minimize flood damage and promote better decisions addressing sustainable development.

  14. 2-D NUMERICAL SIMULATION OF RADIONUCLIDE TRANSPORT IN THE LOWER YANGTZE RIVER

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wan-shun; ZHAO Yan-xin; XU Yan-hong; WANG Yong-gui; PENG Hong; XU Gao-hong

    2012-01-01

    The assessment of the radiological impact of the liquid discharges from nuclear power plants is a major issue for the environmental protection.In this study,a nuberical model for the radionuclide transport in the aquatic enviroument is built,based on the hydrodynamic equations,including the complete set of Saint-Venant equations,the sediment transport equations,with consideration of several different particle sizes and the deposition and erosion of the suspended sediments,and the radionuclide transport equations.The exchanges of radionuclides between water,suspended matter and bed sediments are described in terms of kinetic transfer coefficients.The model is used to simulate the transport of the radionuclides discharged from a planned nuclear power plant project to be sited along the lower Yangtze River.From the model results,one may see the detailed temporal-spatial evolution of the radionuclide contamination in the solution,in the suspended matter and in the bed sediments.The model can be used as a basic tool for studying the environmental impacts of the liquid discharges from nuclear facilities on a river system.

  15. Phytoplankton Assemblage of Yangtze River Estuary and the Adjacent East China Sea in Summer, 2004

    Institute of Scientific and Technical Information of China (English)

    LUAN Qingshan; SUN Jun; SHEN Zhiliang; SONG Shuqun; WANG Min

    2006-01-01

    A cruise was conducted from late August to early September 2004 with the intention of obtaining an interdisciplinary understanding of the Yangtze River Estuary including the biological, chemical and physical subjects. Water sample analysis indicated that total phytoplankton species richness was 137. Of them 81 were found in Bacillariophyta and 48 in Pyrrophyta, accounting for 59.1% and 35.0% respectively. The average cell abundance of surface water samples was 8.8 ×104 cells L-1, with the maximum, 102.9 × 104 cells L- 1, encountered in the area (31.75°N, 122.33°E) and the minimum, 0.2× 104 cells L-1, in (30.75°N, 122.17°E). The dominant species at most stations were Skeletonema costatum and Proboscia alata f. gracillima with the dominance of 0.35 and 0.27. Vertical distribution analysis indicated that obvious stratification of cell abundance and dominant species was found in the representative stations of 5, 18 and 33. Shannon-Wiener index and evenness of phytoplankton assemblage presented negative correlation with the cell abundance, with the optimum appearing in (30.75°N, 122.67°E). According to the PCA analysis of the environmental variables, elevated nutrients of nitrate, silicate and phosphate through river discharge were mainly responsible for the phytoplankton bloom in this area.

  16. Analogue-dynamical Prediction of Numerical Model Errors in the Mid-Lower Reaches of the Yangtze River

    OpenAIRE

    Wang, Qiguang; Feng, Aixia; Feng, Guolin; Zheng, Zhihai

    2011-01-01

    A new prediction error correction scheme based on 74 circulation characteristics data provided by Weather Diagnostic Forecasting Division of National Climate Center, which is designed to develop the Operational Numerical Forecast Model (ONFM) of the National Climate Center of China, and the skill level of the precipitation prediction for rainy season in the midlower reaches (MLR) of the Yangtze River by ONFM is obviously raised. The approach use principal component(PC) analysis to prediction ...

  17. Prediction and prevention of the impacts of sea level rise on the Yangtze River Delta and its adjacent areas

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The Yangtze River Delta region is characterized by high density of population and rapidly developing economy. There are low lying coastal plain and deltaic plain in this region. Thus, the study area could be highly vulnerable to accelerated sea level rise caused by global warming. This paper deals with the scenarios of the relative sea level rise in the early half period of the 21st century in the study area. The authors suggested that relative sea level would rise 25 50 cm by the year 2050 in the study area, of which the magnitude of relative sea level rise in the Yangtze River Delta would double the perspective worldwide average. The impacts of sea level rise include: (i) exacerbation of coastline recession in several sections and vertical erosion of tidal flat, and increase in length of eroding coastline; (ii) decrease in area of tidal flat and coastal wetland due to erosion and inundation; (iii) increase in frequency and intensity of storm surge, which would threaten the coastal protection works; (iv) reduction of drainage capacity due to backwater effect in the Lixiahe lowland and the eastern lowland of Taihu Lake region, and exacerbation of flood and waterlogging disasters; and (v) increase in salt water intrusion into the Yangtze Estuary. Comprehensive evaluation of sea level rise impacts shows that the Yangtze River Delta and eastern lowland of Taihu Lake region, especially Shanghai Municipality, belong in the district in the extreme risk category and the next is the northern bank of Hangzhou Bay, the third is the abandoned Yellow River delta, and the district at low risk includes the central part of north Jiangsu coastal plain and Lixiahe lowland.

  18. Uptake and distribution of N, P and heavy metals in three dominant salt marsh macrophytes from Yangtze River estuary, China

    OpenAIRE

    Quan, W.M.; Han, J.D.; Shen, A.L.; Ping, X.Y.; Qian, P.L.; Li, C.J.; Shi, L.Y.; Chen, Y. Q.

    2007-01-01

    Uptake and distribution of N, P and heavy metals in three dominant salt marsh macrophytes from Yangtze River estuary, China correspondence: Corresponding author. Tel.: +86 21 6568 0293; fax: +86 21 6568 0293. (Chen, Y.Q.) (Quan, W.M.) (Chen, Y.Q.) Key and Open Laboratory of Marine and Estuarine Fisheries, Ministry of Agriculture, East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Sci...

  19. Impact of Cascaded Reservoirs Group on Flow Regime in the Middle and Lower Reaches of the Yangtze River

    Directory of Open Access Journals (Sweden)

    Weixin Duan

    2016-05-01

    Full Text Available A large number of reservoirs have been built in the Yangtze River basin in the last few decades, the operation of which inevitably impacts on natural runoff. It is important to quantify the impacts of a cascade reservoir group operation on the hydrological regime in the downstream Yangtze River. The indicators of hydrologic alteration (IHA, range of variability approach (RVA, and Dundee hydrological regime assessment (DHRA methods, which are based on five essential characteristics, i.e., magnitude, time, frequency, retardation, and rates of change, have been widely used to quantitatively analyze variation in the hydrological regime before and after the dam construction. The observed flow series at Yichang and Datong hydrological stations, located in the middle and lower reaches of the Yangtze River, respectively, are divided into pre- and post-dam construction periods by the Mann-Kendall (MK rank correlation method. The results of the MK test reveal that the annual minimum discharge at Yichang Station has significantly changed since 2000. The analysis results of the IHA, RVA, and DHAR methods show that the hydrologic regime changed moderately after 1999 and is close to severe change after 2008 at Yichang station; and changed slightly after 1999 (the post-dam construction period and moderately after 2008 at Datong station. A new typical year assessment method that can avoid the requirement for a long data series was proposed and compared with the RVA and DHAR methods. The results indicate that the hydrologic regime severely changed at Yichang station and moderately changed at Datong in 2014, which is consistent with the results of the above methods. This study further demonstrates that the changes are mainly reflected in the factors related to low flow such as mean discharge from January to March, minimum discharge, frequency and duration of low pulse, and so on. It is expected that further hydrological alterations will occur as the number of

  20. Modeling of the anthropogenic heat flux and its effect on air quality over the Yangtze River Delta region, China

    OpenAIRE

    Xie, M.; Liao, J; T. Wang; Zhu, K.; B. Zhuang; Han, Y.; Li, M; Li, S.

    2015-01-01

    Anthropogenic heat (AH) emissions from human activities caused by urbanization can affect the city environment. Based on the energy consumption and the gridded demographic data, the spatial distribution of AH emission over the Yangtze River Delta (YRD) region is estimated. Meanwhile, a new method for the AH parameterization is developed in the WRF/Chem model, which incorporates the gridded AH emission data with the seasonal and the diurnal...

  1. 水利部长江水利委员会简介%CHANGJIANG WATER RESOURCES COMMISSION IN BRIEF

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The Changjiang Water Resources Commission(CWRC), originally named Yangtze Valley Planning Office(YVPO), was established in February, 1950.   As an assistant ministry in administrative level, CWRC is a river valley organization dispatched by the Ministry of Water Resources (MWR), PRC. It is authorized by the State to exercise part of the administrative functions of water management within the Changjiang Valley(or Yangtze River Valley) and other rivers in south-west China, namely the unified management of the water resources of the valley and the rivers thereof in accordance with the“Water Law of the Peoples Republic of China”. CWRC is responsible for comprehensive regulation of the valley and development and management of those significant and controlling water projects, doing its best in terms of their planning, management, coordination and monitoring with all the necessary services provided so as to promote rivers harnessing and comprehensive exploitation and protection of the water resources available therein.   Since its establishment 51 years ago, CWRC has done a lot of work in geological survey, hydrological investigation, water resources protection, soil and water conservation, planning and designing as well as scientific research for the valley, with a wealth of basic data, topographical, geological, hydrological,sediment-oriented, socioeconomic and else, collected and compiled in an all-round way. CWRC-issued and revised, a report, entitled the“Essentials on the Changjiang Valley Comprehensive Utilization Planning”,was eventually approved by the State Council, and then it became an official legislative document for subsequent implementation of the river valley regulation and development program. Besides, planning efforts were also made for quite a number of transprovincial and important tributaries in addition to the regulation planning for the main river proper.

  2. THREE-DIMENSIONAL NONLINEAR NUMERICAL MODEL WITH INCLINED PRESSURE FOR SALTWATER INTRUSION AT THE YANGTZE RIVER ESTUARY

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A three-dimensional nonlinear numerical model with inclined pressure was developed to compute the saltwater intrusion at the Yangtze River Estuary. The σ-transformation was introduced in the vertical plane to achieve the same lattices in the whole domain of interest. The mode-splitting technique splits the three-dimensional governing equations into the surface gravity waves (external mode) and the internal gravity waves (internal mode). And the external mode was solved by the improved double-sweep-implicit (DSI) finite difference method and the internal mode was solved by the Eulerian-Lagrangian method. The Eulerian-Lagrangian method could not only reduce the numerical diffusion but also increase the computational accuracy by the improvement of the finite difference scheme in the vertical direction. Application of the model to the Yangtze River Estuary was carried out for the calculation of the saltwater intrusion and the null point. Results of the temporal and spatial distribution of the flow velocity and the salinity coincide with the measured data quite well. The formation and location of the underwater sandbars in the North Channel of the Yangtze River Estuary are closely related to the local salinity, the null point, the predominant current and the residual flow.

  3. Effect of conservation efforts and ecological variables on waterbird population sizes in wetlands of the Yangtze River

    Science.gov (United States)

    Zhang, Yong; Jia, Qiang; Prins, Herbert H. T.; Cao, Lei; de Boer, Willem Frederik

    2015-11-01

    Forage quality and availability, climatic factors, and a wetland’s conservation status are expected to affect the densities of wetland birds. However, the conservation effectiveness is often poorly studied. Here, using twelve years’ census data collected from 78 wetlands in the Yangtze River floodplain, we aimed to understand the effect of these variables on five Anatidae species, and evaluate the effectiveness of the conservation measures by comparing population trends of these species among wetlands that differ in conservations status. We showed that the slope angle of a wetland and the variation thereof best explain the differences in densities of four species. We also found that the population abundances of the Anatidae species generally declined in wetlands along the Yangtze River floodplain over time, with a steeper decline in wetlands with a lower protection status, indicating that current conservation policies might deliver benefits for wintering Anatidae species in China, as population sizes of the species were buffered to some extent against decline in numbers in wetlands with a higher level protection status. We recommend several protection measures to stop the decline of these Anatidae species in wetlands along the Yangtze River floodplain, which are of great importance for the East Asian-Australasian Flyway.

  4. 30-year changes in the nitrogen inputs to the Yangtze River Basin

    International Nuclear Information System (INIS)

    To understand both spatial and temporal changes in nitrogen inputs to the Yangtze River Basin (YRB), we collected decadal statistical data for 1980, 1990, 2000 and 2010 at the county level and the annual statistical data for the period 1980–2010 at the provincial level of China. Based on these datasets, we estimated the nitrogen inputs, including the atmospheric deposition, synthetic N fertilizer, biological N fixation and recycling reactive N inputs, such as N from human waste and animal excrement, crop residue recycled as manure, and N emission from burning crop residue. The results showed that, geographically, the variation of the total amount of N input during the last 30 years (δN = N2010 – N1980) has increased about 0–50 kg ha−1 over most of the area of the YRB. Moreover, it has increased dramatically by about 50–300 kg ha−1 in the Sichuan Basin, the Han River Basin, the Poyang and Dongting lake basins, and the Yangtze Delta as well. Temporally, the total amount of N inputs to the whole YRB was approximately 16.4 Tg N in 2010, which was a 2.0-fold increase over 1980. It increased dramatically in the 1990s and then stabilized at a high level in the 2000s. The major N inputs were human and animal wastes as well as synthetic fertilizers, but they varied regionally. Animal waste was the major input to the water source regions, and its contribution percentage gradually decreased from upper to lower reaches. In contrast, the contribution of N fertilizer increased from upper to lower reaches, and became the major input to the middle and lower reaches. The total N inputs changed slightly in the upper reaches, but increased largely in the middle reaches in the last 30 years. However, in the lower reaches, it had increased remarkably before 2000, and then tended to decrease in the last decade. Finally, the atmospheric N deposition over the basin increased continuously in the last 30 years. (paper)

  5. 长江东流河道整治对长江江豚种群数量的影响%Impact of river training on the population abundance of Yangtze finless porpoises in Dongliu section of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    于道平; 黄敏毅; 赵凯; 陈寿文

    2012-01-01

    The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) is an endemic mammal in the middle and lower reaches of the Yangtze River, and generally appears around river bars and shallow edge beaches. The river training produces negative impacts on the cetacean because of alteration of the hydrological environment for fishes. Using three surveys in the Dongliu section of the Yangtze before the river training project and another three surveys after the project group structure and size of the porpoise in three flow patterns were compared. The results showed that the Yangtze finless porpoise were found mostly in separations near side bars, and secondly in bifurcations above a bar before river training. After implementation, the annual rate of decrease of the porpoise was about 8. 9%. The Yangtze finless porpoise has vanished in the bifurcation zone, and is less dense in the separation zone while rapidly shifting among flow patterns in the regulated river. The results of this study also suggest that the Yangtze finless porpoise is exposed to more and more difficulty in the mainstream of the river. It is urgently that the Yangtze finless porpoise be translocated into an old channel from the mainstream of the Dongliu section.%长江江豚是生活在长江中下游的濒危水生哺乳动物,通常活动在江心洲和浅水缓滩附近.航道整治改变了鱼类栖息活动的水文环境,也给豚类生存带来负面影响.本文根据长江东流河道整治施工前和施工后各3次野外考察资料,分析了3种流态中江豚的数量与群结构.结果表明,该工程实施前江豚主要栖息活动在边滩的分离区,其次在洲头的分流区.工程实施后,整治江段的江豚种群数量年下降率达8.9%.江豚在分流区活动已消失,在分离区集群规模较小,且在流态之间移动增大.本文研究结果也提示长江江豚就地保护难度越来越大,从长江干流中把长江江豚迁入故道中是一件刻不容缓的工作.

  6. Effects of Three Gorges Reservoir (TGR water storage in June 2003 on Yangtze River sediment entering the estuary

    Directory of Open Access Journals (Sweden)

    Z. X. Chu

    2006-07-01

    Full Text Available The world-greatest water conservancy project, Three Gorges Reservoir (TGR, stored water for the first time in June 2003, which provides an excellent opportunity to examine its effects on the sediment entering the Yangtze River estuary. A daily record dataset of water discharge and suspended sediment concentration (SSC of the Yangtze River measured at Datong (the controlling hydrological gauging station into the estuary from May 15 to July of 2003 spanning the water storage, together with a monthly record dataset of runoff, sediment load and SSC measured at Datong from 1953 to 2003, were used to examine the effects of the TGR water storage in June 2003 on the Yangtze River sediment entering the estuary. The results show that the unnaturally clearer water due to the TGR sedimentation resulted by the water storage in June 2003 brought the Yangtze River markedly decreased SSC and sediment load entering the estuary both during the TGR water storage and in the second half year of 2003.

    The Yangtze River water and sediment discharges into the estuary from 15 May to 15 July in 2003 spanning the TGR water storage clearly indicated three phases: (1 pre-water storage of the TGR from 15 May to 25 May, during this phase, SSC and sediment load increased with water discharge increasing; (2 water storage of the TGR from 25 May to 10 June (including the preparation phase from 25 May to 31 May, during this phase, SSC and sediment load decreased dramatically with water discharge decreasing; and (3 post-water storage of the TGR, at the beginning, SSC, sediment load and water discharge basically remained at a relatively low value until the end of June, and since then, SSC and sediment load increased gradually with water discharge increasing. In addition, the real total sediment load was reduced by 2456.07×104 t than the estimated total sediment load during the period from 27 May to 2 July in 2003.

  7. Impact of the exceptionally high flood from the Changjiang River on the aquatic chemical distributions on the Huanghai Sea and East China Sea shelves in the summer of 1998

    Institute of Scientific and Technical Information of China (English)

    WANG Baodong; WANG Xiulin

    2006-01-01

    On the basis of the field observation in the Huanghai Sea and East China Sea in the summer of 1998, a rare event of exceptionally high discharge from the Changjiang River was described and how this high discharge altered water masses as well as chemical distributions on the shelves of the Huanghai Sea and East China Sea. The maximal extending ranges of the Changjiang diluted water and the nutrients in the freshwater from the Changjiang River were recorded for the first time. It was also found that there was a closed area with high oxygen and pH values in the offshore area of the southern Huanghai Sea and the northern East China Sea, indicating that the extensive spreading of nutrients due to the high discharge led to photosynthesis of phytoplankton mostly taking place in the offshore area far from the river mouth. The presence of "excess nitrogen" in almost all the northern East China Sea and the south of the Huanghai Sea suggests that these areas are potentially phosphorus-limited rather than nitrogen-limited, manifesting more like an estuarine ecosystem rather than a common marine ecosystem.

  8. Multivariate Regression Analysis and Statistical Modeling for Summer Extreme Precipitation over the Yangtze River Basin, China

    Directory of Open Access Journals (Sweden)

    Tao Gao

    2014-01-01

    Full Text Available Extreme precipitation is likely to be one of the most severe meteorological disasters in China; however, studies on the physical factors affecting precipitation extremes and corresponding prediction models are not accurately available. From a new point of view, the sensible heat flux (SHF and latent heat flux (LHF, which have significant impacts on summer extreme rainfall in Yangtze River basin (YRB, have been quantified and then selections of the impact factors are conducted. Firstly, a regional extreme precipitation index was applied to determine Regions of Significant Correlation (RSC by analyzing spatial distribution of correlation coefficients between this index and SHF, LHF, and sea surface temperature (SST on global ocean scale; then the time series of SHF, LHF, and SST in RSCs during 1967–2010 were selected. Furthermore, other factors that significantly affect variations in precipitation extremes over YRB were also selected. The methods of multiple stepwise regression and leave-one-out cross-validation (LOOCV were utilized to analyze and test influencing factors and statistical prediction model. The correlation coefficient between observed regional extreme index and model simulation result is 0.85, with significant level at 99%. This suggested that the forecast skill was acceptable although many aspects of the prediction model should be improved.

  9. Assessment of the Mutagenicity of Sediments from Yangtze River Estuary Using Salmonella Typhimurium/Microsome Assay.

    Directory of Open Access Journals (Sweden)

    Li Liu

    Full Text Available Sediments in estuaries are of important environmental concern because they may act as pollution sinks and sources to the overlying water body. These sediments can be accumulated by benthic organisms. This study assessed the mutagenic potential of sediment extracts from the Yangtze River estuary by using the Ames fluctuation assay with the Salmonella typhimurium his (- strain TA98 (frameshift mutagen indicator and TA100 (baseshift mutagen indicator. Most of the sediment samples were mutagenic to the strain TA98, regardless of the presence or absence of exogenous metabolic activation (S9 induction by β-naphthoflavone/phenobarbital. However, none of the samples were mutagenic to the strain TA100. Thus, the mutagenicity pattern was mainly frameshift mutation, and the responsible toxicants were both direct (without S9 mix and indirect (with S9 mix mutagens. The mutagenicity of the sediment extracts increased when S9 was added. Chemical analysis showed a poor correlation between the content of priority polycyclic aromatic hydrocarbons and the detected mutagenicity in each sample. The concept of effect-directed analysis was used to analyze possible compounds responsible for the detected mutagenic effects. With regard to the mutagenicity of sediment fractions, non-polar compounds as well as weakly and moderately polar compounds played a main role. Further investigations should be conducted to identify the responsible components.

  10. Extensive organohalogen contamination in wildlife from a site in the Yangtze River Delta.

    Science.gov (United States)

    Zhou, Yihui; Asplund, Lillemor; Yin, Ge; Athanassiadis, Ioannis; Wideqvist, Ulla; Bignert, Anders; Qiu, Yanling; Zhu, Zhiliang; Zhao, Jianfu; Bergman, Åke

    2016-06-01

    The environmental and human health concerns for organohalogen contaminants (OHCs) extend beyond the 23 persistent organic pollutants (POPs) regulated by the Stockholm Convention. The current, intense industrial production and use of chemicals in China and their bioaccumulation makes Chinese wildlife highly suitable for the assessment of legacy, novel and emerging environmental pollutants. In the present study, six species of amphibians, fish and birds were sampled from paddy fields in the Yangtze River Delta (YRD) were screened for OHCs. Some extensive contamination was found, both regarding number and concentrations of the analytes, among the species assessed. High concentrations of chlorinated paraffins were found in the snake, Short-tailed mamushi (range of 200-340μgg(-)(1)lw), Peregrine falcon (8-59μgg(-1)lw) and Asiatic toad (97μgg(-)(1)lw). Novel contaminants and patterns were observed; octaCBs to decaCB made up 20% of the total polychlorinated biphenyls (PCBs) content in the samples and new OHCs, substituted with 5-8 chlorines, were found but are not yet structurally confirmed. In addition, Dechlorane 602 (DDC-DBF) and numerous other OHCs (DDTs, hexachlorocyclohexanes (HCHs), polybrominated diphenyl ethers (PBDEs), hexbromocyclododecane (HBCDD), chlordane, heptachlor, endosulfan and Mirex) were found in all species analyzed. These data show extensive chemical contamination of wildlife in the YRD with a suite of OHCs with both known and unknown toxicities, calling for further in-depth studies. PMID:26956179

  11. Design of the Long-term Safety Monitoring System of Zhicheng Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The long-term safety monitoring system of Zhicheng Yangtze River Bridge was established in the principle of open information service and standardized systems engineering.The ADSL dynamic IP communication network established by using VPN technology and application of encryption technology,tunnel technology and user identification accreditation technology have made the system safer and more reliable.The system can fulfill real-time,regular and triggered signal collection according to needs and may give notice or alarm for the discovery of real-time failure.Monitored data can be collected and stored to provide reliable data for stipulating technical indicators for safety operation of the large-span railway bridges.The system,after its completion,can maintain its long-term stable running,take hold of the running condition of all locations of bridge under monitoring,evaluate the overall situation and life cycle,and make available the technical reserves for the Infrastructure Inspection Center of MOR.

  12. Dynamic channel adjustments in the Jingjiang Reach of the Middle Yangtze River.

    Science.gov (United States)

    Xia, Junqiang; Deng, Shanshan; Lu, Jinyou; Xu, Quanxi; Zong, Quanli; Tan, Guangming

    2016-01-01

    Significant channel adjustments have occurred in the Jingjiang Reach of the Middle Yangtze River, because of the operation of the Three Gorges Project (TGP). The Jingjiang Reach is selected as the study area, covering the Upper Jingjiang Reach (UJR) and Lower Jingjiang Reach (LJR). The reach-scale bankfull channel dimensions in the study reach were calculated annually from 2002 to 2013 by means of a reach-averaged approach and surveyed post-flood profiles at 171 sections. We find from the calculated results that: the reach-scale bankfull widths changed slightly in the UJR and LJR, with the corresponding depths increasing by 1.6 m and 1.0 m; the channel adjustments occurred mainly with respect to bankfull depth because of the construction of large-scale bank revetment works, although there were significant bank erosion processes in local regions without the bank protection engineering. The reach-scale bankfull dimensions in the UJR and LJR generally responded to the previous five-year average fluvial erosion intensity during flood seasons, with higher correlations being obtained for the depth and cross-sectional area. It is concluded that these dynamic adjustments of the channel geometry are a direct result of recent human activities such as the TGP operation. PMID:26965069

  13. Winter temperature variations over the middle and lower reaches of the Yangtze River since 1736 AD

    Science.gov (United States)

    Hao, Z.-X.; Zheng, J.-Y.; Ge, Q.-S.; Wang, W.-C.

    2012-06-01

    We present statistically reconstructed mean annual winter (December-February) temperatures from the middle and lower reaches of the Yangtze River (24° N-34° N, 108° E-123° E within mainland China) extending back to 1736. The reconstructions are based on information regarding snowfall days from historical documents of the Yu-Xue-Fen-Cun archive recorded during the Qing Dynasty (1644-1911). This information is calibrated with regional winter temperature series spanning the period from 1951 to 2007. The gap from 1912 to 1950 is filled using early instrumental observations. With the reference period of 1951-2007, the 18th century was 0.76 °C colder, and the 19th century was 1.18 °C colder. However, since the 20th century, the climate has been in a warming phase, particularly in the last 30 yr, and the mean temperature from 1981 to 2007 was 0.25 °C higher than that of the reference period of 1951-2007, representing the highest temperatures of the past 300 yr. Uncertainty existed for the period prior to 1900, and possible causes of this uncertainty, such as physical processes involved in the interaction between temperature and snowfall days and changing of observers, are discussed herein.

  14. Winter temperature variations over the middle and lower reaches of the Yangtze River since 1736 AD

    Directory of Open Access Journals (Sweden)

    Z.-X. Hao

    2012-06-01

    Full Text Available We present statistically reconstructed mean annual winter (December–February temperatures from the middle and lower reaches of the Yangtze River (24° N–34° N, 108° E–123° E within mainland China extending back to 1736. The reconstructions are based on information regarding snowfall days from historical documents of the Yu-Xue-Fen-Cun archive recorded during the Qing Dynasty (1644–1911. This information is calibrated with regional winter temperature series spanning the period from 1951 to 2007. The gap from 1912 to 1950 is filled using early instrumental observations. With the reference period of 1951–2007, the 18th century was 0.76 °C colder, and the 19th century was 1.18 °C colder. However, since the 20th century, the climate has been in a warming phase, particularly in the last 30 yr, and the mean temperature from 1981 to 2007 was 0.25 °C higher than that of the reference period of 1951–2007, representing the highest temperatures of the past 300 yr. Uncertainty existed for the period prior to 1900, and possible causes of this uncertainty, such as physical processes involved in the interaction between temperature and snowfall days and changing of observers, are discussed herein.

  15. Dynamic channel adjustments in the Jingjiang Reach of the Middle Yangtze River

    Science.gov (United States)

    Xia, Junqiang; Deng, Shanshan; Lu, Jinyou; Xu, Quanxi; Zong, Quanli; Tan, Guangming

    2016-03-01

    Significant channel adjustments have occurred in the Jingjiang Reach of the Middle Yangtze River, because of the operation of the Three Gorges Project (TGP). The Jingjiang Reach is selected as the study area, covering the Upper Jingjiang Reach (UJR) and Lower Jingjiang Reach (LJR). The reach-scale bankfull channel dimensions in the study reach were calculated annually from 2002 to 2013 by means of a reach-averaged approach and surveyed post-flood profiles at 171 sections. We find from the calculated results that: the reach-scale bankfull widths changed slightly in the UJR and LJR, with the corresponding depths increasing by 1.6 m and 1.0 m the channel adjustments occurred mainly with respect to bankfull depth because of the construction of large-scale bank revetment works, although there were significant bank erosion processes in local regions without the bank protection engineering. The reach-scale bankfull dimensions in the UJR and LJR generally responded to the previous five-year average fluvial erosion intensity during flood seasons, with higher correlations being obtained for the depth and cross-sectional area. It is concluded that these dynamic adjustments of the channel geometry are a direct result of recent human activities such as the TGP operation.

  16. Phosphorus forms and bioavailability of lake sediments in the middle and lower reaches of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    ZHU; Guangwei; QIN; Boqiang; ZHANG; Lu

    2006-01-01

    Forms of phosphorus in sediments from 25 lakes in the middle and lower reaches of Yangtze River were analyzed by the sequential extraction procedure. Contents and spatial distrubution of algal available phosphorus (AAP) in sediments of Lake Taihu, the third largest freshwater lake of China, were also studied. Relationships between phosphorus forms in sediment and macrophytes coverage in sample sites, as well as phosphorus forms in sediments and chlorophyal contents in lake water were discussed. Exchangeable form of phosphorus (Ex-P) in surface sediments was significantly positive correlative to total phosphorus (TP), dissolved total phosphorus (DTP) and soluble reactive phosphorus (SRP) contents in the lake water. Bioavailable phosphorus (Bio-P) contents in sediments from macrophytes dominant sites were significantly lower than that in no macrophyte sites. In Lake Taihu, Ex-P content in top 3 cm sediment was highest.However, content of ferric fraction phosphorus (Fe-P) was highest in 4-10 cm. Bioavalilble phosphorus (Bio-P) contents in surface sediments positively correlated to Chlorophyll a contents in water of Lake Taihu with significant difference. Therefore, contents of Bio-P and AAP could be acted as the indicators of risks of internal release of phosphorus in the shallow lakes. It was estimated that there were 268.6 ton AAP in top 1 cm sediments in Lake Taihu. Sediment suspension caused by strong wind-induced wave disturbance could carry plenty of AAP into water in large shallow lakes like Lake Taihu.

  17. Particulate matter pollution research in the Yangtze River Delta: Observations, processes, modeling and health effects

    Science.gov (United States)

    Yu, Jian Zhen; Cao, Junji; Hu, Min; Kan, Haidong; Fu, Tzung-May

    2015-12-01

    The Yangtze River Delta (YRD) covers an area of 110,915 square km, including seven cities of northern Zhejiang Province, the Shanghai municipality and eight cities of southern Jiangsu Province. It is home to ∼110 million people and its GDP accounts for 17.4% of the whole China Economy (Hong Kong Trade Development Council Research, 2013). The YRD economy is greatly driven by heavy industries such as machinery, chemicals and automobile manufacturing. It is also a large producer of agricultural products, including wheat, rice, and corn. Its transport infrastructure is highly developed, with the number of vehicles per km2 higher than that in the developed countries. Two out of the ten top ports in China (Shanghai and Ningbo-Zhoushan ports) are located in the YRD. As a fast-developing and an important economic powerhouse of the Chinese Mainland, worsening of air quality and increasing pollution episodes in this region has led to heightened public health concerns and intensified research.

  18. Aquifer Arsenic Cycling Induced by Seasonal Hydrologic Changes within the Yangtze River Basin.

    Science.gov (United States)

    Schaefer, Michael V; Ying, Samantha C; Benner, Shawn G; Duan, Yanhua; Wang, Yanxin; Fendorf, Scott

    2016-04-01

    Consumption of groundwater containing >10 μg L(-1) arsenic (As) adversely impacts more than 100 million people worldwide. Multiyear trends in aquifer As concentrations have been documented, but strong seasonal variations are not commonly observed. Here we report dramatic seasonal changes in As concentrations and aquifer chemistry within the Jianghan Plain of the Yangtze River, China. At some wells, concentrations fluctuate by more than an order of magnitude within a single year (100-1200 μg L(-1)). Groundwater extraction and sustained water levels of surface channels during the dry season induces a strong downward hydraulic gradient, seasonally supplying oxidizing (oxygen, nitrate) water to the otherwise anoxic aquifer. Oxygen and/or nitrate addition promotes a transient drop in As concentrations for 1-3 months. When recharge ceases, reducing, low-arsenic conditions are reestablished by reactive, endogenous organic carbon. Temporal variability in As concentrations is especially problematic because it increases the probability of false-negative well testing during low-arsenic seasons. However, periods of low As may also provide a source of less toxic water for irrigation or other uses. Our results highlight the vulnerability and variability of groundwater resources in the Jianghan Plain and other inland basins within Asia to changing geochemical conditions, both natural and anthropogenic, and reinforce that continued monitoring of wells in high-risk regions is essential. PMID:26788939

  19. Analysis of a severe prolonged regional haze episode in the Yangtze River Delta, China

    Science.gov (United States)

    Wang, Mengya; Cao, Chunxiang; Li, Guoshuai; Singh, Ramesh P.

    2015-02-01

    A severe prolonged regional haze episode occurred over the Yangtze River Delta (YRD) from 2 to 14 December 2013. In this paper, we have discussed the probable cause of haze episode and aerosol characteristics. Analysis of visibility and meteorological parameters suggest that the meteorological conditions play a very important role in the accumulation of aerosol particles that cause haze. The height of the planetary boundary layer (PBL) is considered as one of the key factors together with other factors in the haze formation. The Principal Component Analysis (PCA) clearly shows accumulation process of air pollutants from vehicular, industrial and anthropogenic sources are major contributors for the haze formation. The aerosol optical properties (aerosol optical depth - AOD, Ångström exponent - α and Ultra Violet Aerosol Index - UVAI) are analyzed to study the temporal and spatial variations of aerosol loadings. The results show concentrations of fine mode particles during the haze episode, the dust could have been also entered in the region from the northwestern China. Analysis of vertical aerosol profiles indicate that dust aerosols concentrated in the lower part of the haze layers.

  20. Spatiotemporal Variations of Cloud Amount over the Yangtze River Delta, China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wenjing,ZHANG Ning,; SUN Jianning

    2014-01-01

    Based on the NOAA’s Advanced Very High Resolution Radiometer (AVHRR) Pathfi nder Atmospheres Extended (PATMOS-x) monthly mean cloud amount data, variations of annual and seasonal mean cloud amount over the Yangtze River Delta (YRD), China were examined for the period 1982-2006 by using a linear regression analysis. Both total and high-level cloud amounts peak in June and reach minimum in December, mid-level clouds have a peak during winter months and reach a minimum in summer, and low-level clouds vary weakly throughout the year with a weak maximum from August to October. For the annual mean cloud amount, a slightly decreasing tendency (-0.6% sky cover per decade) of total cloud amount is observed during the studying period, which is mainly due to the reduction of annual mean high-level cloud amount (-2.2% sky cover per decade). Mid-level clouds occur least (approximately 15% sky cover) and remain invariant, while the low-level cloud amount shows a signifi cant increase during spring (1.5% sky cover per decade) and summer (3.0%sky cover per decade). Further analysis has revealed that the increased low-level clouds during the summer season are mainly impacted by the local environment. For example, compared to the low-level cloud amounts over the adjacent rural areas (e.g., cropland, large water body, and mountain areas covered by forest), those over and around urban agglomerations rise more dramatically.

  1. [Major Air Pollutant Emissions of Coal-Fired Power Plant in Yangtze River Delta].

    Science.gov (United States)

    Ding, Qing-qing; Wei, Wei; Shen, Qun; Sun, Yu-han

    2015-07-01

    The emission factor method was used to estimate major air pollutant emissions of coal-fired power plant in the Yangtze River Delta (YRD) region of the year 2012. Results showed that emissions of SO2, NOx, dust, PM10, PM2.5 were respectively 473 238, 1 566 195, 587 713, 348 773 and 179 820 t. For SO2 and NOx, 300 MW and above class units made contributions of 85% and 82% in emission; while in the respect of dust, PM10 and PM2.5 contribution rates of 100 MW and below class units were respectively 81%, 53% and 40%. Considering the regional distribution, Jiangsu discharged the most, followed by Zhejiang, Shanghai. According to discharge data of several local power plants, we also calculated and made a comparative analysis of emission factors in different unit levels in Shanghai, which indicated a lower emission level. Assuming an equal level was reached in whole YRD, SO2 emission would cut down 55. 8% - 65. 3%; for NOx and dust emissions were 50. 5% - 64. 1% and 3. 4% - 11. 3%, respectively. If technologies and pollution control of lower class units were improved, the emission cuts would improve. However, according to the pollution realities of YRD, we suggested to make a multiple-cuts plan, which could effectively improve the reaional atmospheric environment. PMID:26489303

  2. Distribution, historical trends and inventories of polychlorinated biphenyls in sediments from Yangtze River Estuary and adjacent East China Sea

    International Nuclear Information System (INIS)

    A large portion of polychlorinated biphenyls (PCBs) from e-waste released into the coastal areas may be the potential source of PCBs to the global oceans. The paper presents data of PCBs concentrations in fifty surface sediment samples and a dated sediment core in Yangtze River Delta (YRE) and adjacent East China Sea (ECS). The total PCBs levels varied from 5.08 to 19.64 ng/g dry weight, with the highest concentrations situate within the river-sea boundary zone which is so-called “marginal filter”. Concurrent with the operation of e-waste recycling over the last two decades, PCB fluxes started to rise again after 1980s and reached a maximum in this century. The full data set was used to estimate the burden of PCBs in YRE and adjacent ECS. A total sediment burdens were 192.8 tons, with the spatial density of 364 ng/cm2 which accounts for 1.9% of all the PCBs in China. - Highlights: ► PCBs residues remained widespread in Yangtze River Delta and adjacent East China Sea. ► Highest PCBs concentrations situate within the river-sea boundary zone. ► Congener profiles and PCA highlight the influence of e-waste recycling. ► Temporal distributions indicated PCB fluxes reached a maximum in this century. ► Total sediment burdens accounts for 1.9 % of all the PCBs in China. - Spatial and temporal distributions of polychlorinated biphenyls have been delineated in sediments from Yangtze River Estuary and adjacent East China Sea.

  3. An 800-year record of terrestrial organic matter from the East China Sea shelf break: Links to climate change and human activity in the Changjiang Basin

    Science.gov (United States)

    Li, Zhong Qiao; Wu, Ying; Liu, Su Mei; Du, Jin Zhou; Zhang, Jing

    2016-02-01

    The East China Sea (ECS) is a large river dominated marginal sea and receives massive volumes of terrestrial material from the Changjiang (Yangtze River). As the ECS preserves a record of terrestrial material derived from the Changjiang Basin, cores collected from this region can be used to reconstruct paleoclimate change and human disturbance in the watershed. A core (P4) was collected from the ECS shelf break and analyzed for bulk parameters (organic carbon (OC), total nitrogen (TN), and stable carbon isotopes (δ13C)), lignin phenols, and 3,5-dihydroxy benzoic acid (DHBA). The depth profiles of these parameters indicate stable and consistent marine production. The lignin source indices, cinnamyl phenols vs. vanillyl phenols (C/V) and syringyl phenols vs. vanillyl phenols (S/V), were in agreement with previously reported results from ECS surface sediments, but differed markedly from Bohai Sea surface sediments. The ratio of acid to aldehyde in vanillyl phenols ((Ad/Al)v) indicated the terrestrial OC in this core was refractory. At the same time, the variation in lignin phenols is positively correlated with the strength of the Indian Summer Monsoon (ISM) over the last 800 years (phuman activity in the upper Changjiang Basin over this period.

  4. 长江流域1961-2002年极端降水特征%Changing features of extreme precipitation in the Yangtze River basin during 1961-2002

    Institute of Scientific and Technical Information of China (English)

    张增信; 张强; 姜彤

    2007-01-01

    The total precipitation of the highest 1 day, 3 day, 5 day and 7 day precipitation amount (R1D, R3D, R5D and R7D) in the Yangtze River basin was analyzed with the help of linear trend analysis and continuous wavelet transform method. The research results indicated that: 1) Spatial distribution of R1D is similar in comparison with that of R3D, R5D and R7D. The Jialingjiang and Hanjiang river basins are dominated by decreasing trend, which is significant at >95% confidence level in Jialingjiang River basin and insignificant at >95% confidence level in Hanjiang River basin. The southern part of the Yangtze River basin and the western part of the upper Yangtze River basin are dominated by significant increasing trend of R1D extreme precipitation at >95% confidence level. 2) As for the R3D, R5D and R7D, the western part of the upper Yangtze River basin is dominated by significant increasing trend at >95% confidence level. The eastern part of the upper Yangtze River basin is dominated by decreasing trend, but is insignificant at >95% confidence level. The middle and lower Yangtze River basin is dominated by increasing trend, but insignificant at >95% confidence level. 3)The frequency and intensity of extreme precipitation events are intensified over time. Precipitation anomalies indicated that the southeastern part, southern part and southwestern part of the Yangtze River basin are dominated by positive extreme precipitation anomalies between 1993-2002 and 1961-1992. The research results of this text indicate that the occurrence probability of flash flood is higher in the western part of the upper Yangtze River basin and the middle and lower Yangtze River basin, esp. in the southwestern and southeastern parts of the Yangtze River basin.

  5. 江河源区生态环境范围的探讨%Eco-environment range in the source regions of the Yangtze and Yellow rivers

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Based on geographical and hydrological extents delimited, four principles are identified, asthe bases for delineating the ranges of the source regions of the Yangtze and Yellow rivers in thepaper. According to the comprehensive analysis of topographical characteristics, climate conditions,vegetation distribution and hydrological features, the source region ranges for eco-environmentalstudy are defined. The eastern boundary point is Dari hydrological station in the upper reach of theYellow River. The watershed above Dari hydrological station is the source region of the YellowRiver which drains an area of 4.49 × 104 km2. Natural environment is characterized by the majortopographical types of plateau lakes and marshland, gentle landforms, alpine cold semi-arid climate,and steppe and meadow vegetation in the source region of the Yellow River. The eastern boundarypoint is the convergent site of the Nieqiaqu and the Tongtian River in the upstream of the YangtzeRiver. The watershed above the convergent site is the source region of the Yangtze River, with awatershed area of 12.24× 104 km2. Hills and alpine plain topography, gentle terrain, alpine cold aridand semi-arid climate, and alpine cold grassland and meadow are natural conditions in the sourceregion of the Yangtze River.

  6. Evaluation of Impacts from River Engineering Measures at Nanjing Reach of Yangtze River : An Application of Hydrodynamic Modelling and Sediment Transportation Simulations

    OpenAIRE

    Håkansson, Daniel; Palmquist, Marcus

    2014-01-01

    The demand of electric power has rapidly increased in China along with the financial development. High pollution rates have pushed the development towards more renewable energy generating alternatives. In recent years larger investments of hydropower- generated electricity have been to satisfy the increased demand. Hydropower can cause non-energy related problems when implemented in a large scale. In this project the Nanjing Reach of Yangtze River was investigated through a hydrodynamic and s...

  7. Mitochondrial DNA evidence indicates the local origin of domestic pigs in the upstream region of the Yangtze River.

    Directory of Open Access Journals (Sweden)

    Long Jin

    Full Text Available Previous studies have indicated two main domestic pig dispersal routes in East Asia: one is from the Mekong region, through the upstream region of the Yangtze River (URYZ to the middle and upstream regions of the Yellow River, the other is from the middle and downstream regions of the Yangtze River to the downstream region of the Yellow River, and then to northeast China. The URYZ was regarded as a passageway of the former dispersal route; however, this assumption remains to be further investigated. We therefore analyzed the hypervariable segements of mitochondrial DNA from 513 individual pigs mainly from Sichuan and the Tibet highlands and 1,394 publicly available sequences from domestic pigs and wild boars across Asia. From the phylogenetic tree, most of the samples fell into a mixed group that was difficult to distinguish by breed or geography. The total network analysis showed that the URYZ pigs possessed a dominant position in haplogroup A and domestic pigs shared the same core haplotype with the local wild boars, suggesting that pigs in group A were most likely derived from the URYZ pool. In addition, a region-wise network analysis determined that URYZ contains 42 haplotypes of which 22 are unique indicating the high diversity in this region. In conclusion, our findings confirmed that pigs from the URYZ were domesticated in situ.

  8. Assessment of Hydrologic Alterations Caused by the Three Gorges Dam in the Middle and Lower Reaches of Yangtze River, China

    Directory of Open Access Journals (Sweden)

    Liuzhi Jiang

    2014-05-01

    Full Text Available Hydrologic regime plays a major role in structuring biotic diversity within river ecosystems by controlling key habitat conditions within the river channel and floodplain. Daily flow records from seven hydrological stations and the range of variability approach were utilized to investigate the variability and spatial pattern of the hydrologic alterations induced by the construction of the Three Gorges Dam (TGD in the middle and lower reaches of the Yangtze River, China. Results show that the impoundment of the TGD disturbed the hydrologic regime downstream and directly affected the streamflow variations. The rate of changes and the annual extreme conditions were more affected by the TGD, particularly the low-flow relevant parameters. The alterations in the hydrologic regime were mainly caused by the TGD storing water during early autumn and releasing water during winter and spring. The effects on spatial patterns decreased as the distance from the dam increased, which was mainly attributed to the inflows from large tributaries along the Yangtze River as well as the interaction with the two largest natural lakes (i.e., Dongting Lake and Poyang Lake. These hydrologic alterations not only break the natural balance of eco-flow regimes but also result in undesirable ecological effects, particularly in terms of habitat availability for the fish community.

  9. Current and Future Precipitation Extremes over Mississippi and Yangtze River Basins as Simulated in CMIP5 Models

    Institute of Scientific and Technical Information of China (English)

    Zaitao Pan; Yuanjie Zhang; Xiaodong Liu; Zhiqiu Gao

    2016-01-01

    ABSTRACT:Both central-eastern U.S. and China are prone to increasing flooding from Mississippi River and Yangtze River basins respectively. This paper contrasts historical and projected spatial-temporal distribution of extreme precipitation in these two large river basins using 31 CMIP5 (coupled model intercomparison project phase 5) models’ historical and RCP8.5 (representative concentration pathway) experiments. Results show that (1) over both river basins, the heaviest rainfall events have increased in recent decades while the lightest precipitation reduced in frequency. Over Mississippi River Basin, both the lightest precipitation (50 mm/day) would decrease in frequency notably after mid-2020s while intermediate events occur more frequently in future;whe-reas over the Yangtze River Basin, all categories of precipitation are projected to increase in frequen-cy over the coming decades. (2) Although the consensus of CMIP5 models was able to reproduce well domain-time mean and even time-averaged spatial distribution of precipitation, they failed to simulate precipitation trends both in spatial distribution and time means. In a similar fashion, models captured well statistics of precipitation but they had difficulty in representing temporal variations of different precipitation intensity categories. (3) The well-documented 2nd half of the 20th century surface sum-mer cooling over the two river basins showed different associations with precipitation trends with higher anti-correlation between them over the U.S. region, implying different processes contributing to the cooling mechanisms of the two river basins.

  10. The relation between distribution of zooplankton and salinity in the Changjiang Estuary

    Institute of Scientific and Technical Information of China (English)

    GAO Qian; XU Zhaoli; ZHUANG Ping

    2008-01-01

    Seasonal netzplankton samples from stations in the Changjiang (Yangtze River) Estuary were collected from May,2004 to February,2005.The dominant species and their contribution to the total zooplankton abundance were determined.Moreover,the relationship between the salinity and abundance was studied with stepwise linear regression.During the whole year,the salinity was positively correlated with the abundance,while the temperature,negatively.Linear regression analysis showed also a high positive correlation with salinity for total abundance in August and November,while in February and May,no obvious relations were found.The most abundant community was composed of neritic and brackish-water species.The North Passage (NP) (salinity<5) was greatly diluted by freshwater while the North Branch (NB) was brackish water with salinity range of 12-28.Consequently,clear decline in abundance of zooplankton was along the estuarine haloclines from the maximum in the area of high salinity to the minimum in the limnetic zone.Total zooplankton abundance and biomass were lower in NP than the NB in all seasons.In short,the salinity influenced the abundance of each species of zooplankton,and ultimately determined the total abundance of zooplankton.Furthermore,a winter peak in the abundance existed,which might be caused by the flourishing of Sinocalanus sinensis,a widely distributed species in the Changjiang Estuary.

  11. Reflection on Information Index System of the Yangtze River%对长江干线航道信息指标系统的思考

    Institute of Scientific and Technical Information of China (English)

    邓良爱; 刘明俊; 刘佳仑

    2012-01-01

    This paper analyses information index system of the Yangtze River from several aspects, such as waterway information classification, standard of information release , information content, etc, gathered various types of waterway information distribution standards and gave several suggestions about the existing information content where need to improve. It offers direct reference for enhancing the level of the Yangtze River waterway services and service capabilities and improve the Yangtze River waterway construction and management information platform.%从航道信息分类,发布标准及发布内容等几个方面对长江干线航道信息指标系统进行分析,汇总各类航道信息发布标准,并对现有的航道信息发布内容需要完善的方面给出几点建议.

  12. Tidally induced upwelling off Yangtze River estuary and in Zhejiang coastal waters in summer

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    MASNUM wave-tide-circulation coupled numerical model (MASNUM coupled model, hereinafter) is de-veloped based on the Princeton Ocean Model (POM). Both POM and MASNUM coupled model are ap-plied in the numerical simulation of the upwelling off Yangtze River estuary and in Zhejiang coastal waters in summer. The upwelling mechanisms are analyzed from the viewpoint of tide, and a new mechanism is proposed. The study suggests that the tidally inducing mechanism of the upwelling in-cludes two dynamic aspects: the barotropic and the baroclinic process. On the one hand, the residual currents induced by barotropic tides converge near the seabed, and upwelling is generated to maintain mass conservation. The climbing of the residual currents along the sea bottom slope also contributes to the upwelling. On the other hand, tidal mixing plays a very important role in inducing the upwelling in the baroclinic sea circumstances. Strong tidal mixing leads to conspicuous front in the coastal waters. The considerable horizontal density gradient across the front elicits a secondary circulation clinging to the tidal front, and the upwelling branch appears near the frontal zone. Numerical experiments are de-signed to determine the importance of tide in inducing the upwelling. The results indicate that tide is a key and dominant inducement of the upwelling. Experiments also show that coupling calculation of the four main tidal constituents (M2, S2, K1, and O1), rather than dealing with the single M2 constituent, im-proves the modeling precision of the barotropic tide-induced upwelling.

  13. Tidally induced upwelling off Yangtze River estuary and in Zhejiang coastal waters in summer

    Institute of Scientific and Technical Information of China (English)

    L(ü) XinGang; QIAO FangLi; XIA ChangShui; YUAN YeLi

    2007-01-01

    MASNUM wave-tide-circulation coupled numerical model(MASNUM coupled model,hereinafter)is developed based on the Princeton Ocean Model (POM).Both POM and MASNUM coupled model are applied in the numerical simulation of the upwelling off Yangtze River estuary and in Zhejiang coastal waters in summer.The upwelling mechanisms are analyzed from the viewpoint of tide,and a new mechanism is proposed.The study suggests that the tidally inducing mechanism of the upwelling includes two dynamic aspects:the barotropic and the baroclinic process.On the one hand,the residual currents induced by barotropic tides converge near the seabed,and upwelling is generated to maintain mass conservation.The climbing of the residual currents along the sea bottom slope also contributes to the upwelling.On the other hand,tidal mixing plays a very important role in inducing the upwelling in the baroclinic sea circumstances.Strong tidal mixing leads to conspicuous front in the coastal waters.The considerable horizontal density gradient across the front elicits a secondary circulation clinging to the tidal front,and the upwelling branch appears near the frontal zone.Numerical experiments are designed to determine the importance of tide in inducing the upwelling.The results indicate that tide is a key and dominant inducement of the upwelling.Experiments also show that coupling calculation of the four main tidal constituents (M2,S2,K1,and O1),rather than dealing with the single M2 constituent,improves the modeling precision of the barotropic tide-induced upwelling.

  14. Heavy Metal Pollution in a Soil-Rice System in the Yangtze River Region of China

    Directory of Open Access Journals (Sweden)

    Zhouping Liu

    2015-12-01

    Full Text Available Heavy metals are regarded as toxic trace elements in the environment. Heavy metal pollution in soil or rice grains is of increasing concern. In this study, 101 pairs of soil and rice samples were collected from the major rice-producing areas along the Yangtze River in China. The soil properties and heavy metal (i.e., Cd, Hg, Pb and Cr concentrations in the soil and rice grains were analyzed to evaluate the heavy metal accumulation characteristics of the soil-rice systems. The results showed that the Cd, Hg, Pb and Cr concentrations in the soil ranged from 0.10 to 4.64, 0.01 to 1.46, 7.64 to 127.56, and 13.52 to 231.02 mg·kg−1, respectively. Approximately 37%, 16%, 60% and 70% of the rice grain samples were polluted by Cd, Hg, Pb, and Cr, respectively. The degree of heavy metal contamination in the soil-rice systems exhibited a regional variation. The interactions among the heavy metal elements may also influence the migration and accumulation of heavy metals in soil or paddy rice. The accumulation of heavy metals in soil and rice grains is related to a certain extent to the pH and soil organic matter (SOM. This study provides useful information regarding heavy metal accumulation in soil to support the safe production of rice in China. The findings from this study also provide a robust scientific basis for risk assessments regarding ecological protection and food safety.

  15. Inorganic aerosols responses to emission changes in Yangtze River Delta, China

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Xinyi; Li, Juan; Fu, Joshua S.; Gao, Yang; Huang, Kan; Zhuang, Guoshun

    2014-05-15

    China announced the Chinese National Ambient Air Quality standards (CH-NAAQS) on Feb. 29th, 2012, and PM2.5 is for the very first time included in the standards as a criteria pollutant. In order to probe into PM2.5 pollution over Yangtze River Delta, which is one of the major urban clusters hosting more than 80 million people in China, the integrated MM5/CMAQ modeling system is applied for a full year simulation to examine the PM2.5 concentration and seasonality, and also the inorganic aerosols responses to precursor emission changes. Both simulation and observation demonstrated that, inorganic aerosols have substantial contributions to PM2.5 over YRD, ranging from 37.1% in November to 52.8% in May. Nocturnal production of nitrate (NO3-) through heterogeneous hydrolysis of N2O5 was found significantly contribute to high NO3-concentration throughout the year. We also found that in winter NO3- was even increased under nitrogen oxides (NOx) emission reduction due to higher production of N2O5 from the excessive ozone (O3) introduced by attenuated titration, which further lead to increase of ammonium (NH4+) and sulfate (SO42-), while other seasons showed decrease response of NO3-. Sensitivity responses of NO3- under anthropogenic VOC emission reduction was examined and demonstrated that in urban areas over YRD, NO3- formation was actually VOC sensitive due to the O3-involved nighttime chemistry of N2O5, while a reduction of NOx emission may have counter-intuitive effect by increasing concentrations of inorganic aerosols.

  16. New particle formation in the western Yangtze River Delta: first data from SORPES-station

    Directory of Open Access Journals (Sweden)

    E. Herrmann

    2013-01-01

    Full Text Available Aerosols and new particle formation were studied in the western part of the Yangtze River Delta (YRD, at the SORPES station of Nanjing University. Air ions between 0.8 and 42 nm were measured using an air ion spectrometer; a DMPS provided particle size distributions between 6 and 800 nm. Additionally, meteorological data, trace gas concentrations, and PM2.5 values were recorded. During the measurement period from 18 November 2011 to 31 March 2012, the mean total particle concentration was found to be 23 000 cm−3. The mean PM2.5 value was 90 μ g m−3, well above national limits. During the observations, 26 new particle formation events occurred, typically producing 6 nm particles at a rate of 1 cm−3 s−1, resulting in over 4000 cm−3 new CCN per event. Typical growth rates were between 6 and 7 nm h−1. Ion measurements showed the typical cluster band below 2 nm, with total ion concentrations roughly between 600 and 1000 cm−3. A peculiar feature of the ion measurements were the heightened ion cluster concentrations during the nights before event days. The highly polluted air of the YRD provides both the potential source (SO2 and the sink (particulate matter for sulfuric acid, leaving radiation as the determining force behind new particle formation. Accordingly, a good correlation was found between new particle formation rate and radiation values.

  17. Study on the Spatial Stress of the Chongqing Yangtze River Bridge in China

    Directory of Open Access Journals (Sweden)

    Yan Li

    2014-09-01

    Full Text Available Continuous rigid-frame bridges are usually used in building bridges with long span and high piers. It is characterized by the consolidation between piers and beams in the middle of bridge piers and flexible bridge piers in the lower part. Among all the factors, curvature has the most obvious influence on the stress of curved continuous rigid-frame bridge, because of which, the curved beam bridge produces coupling effect of bending moment and receives complicated stress, leading to the deformation such as torsion and displacement of radial direction. No matter it is the castscaffold construction or cantilever construction, for continuous rigid-frame bridges, considering that after the long term creep of concrete, structure stress tends to be in a drop-frame state, so it is necessary to know the mechanical properties of the finished bridge. Taking the Chongqing Yangtze River Bridge as an example, this paper mainly analyzes the internal forces and deformations of a finished curved continuotus rigid-frame bridge by establishing a spatial finite element model with Midas Civil 2006 software and by changing the model’s radius of curvature. The results show that as the curvature increases, the vertical deformation and torsion angle of the long-span curved continuous rigid-frame bridge are both reduced under the effect of a dead load and prestressed load, presenting mechanical properties of bridge, namely, “coupling effect of bending moment”. In the model analyzed, the deformation of the bridge in the transverse direction also behaves a trend of gradual decrease with an increase in radius of curvature with the range 500–2000 m.

  18. Development and Validation of National Cotton Cultivar Registration lndex Model in Yangtze River Valley

    Institute of Scientific and Technical Information of China (English)

    Naiyin XU; Jian Ll

    2014-01-01

    Based on the cotton variety high yielding potential, fiber quality traits, disease resistance, and early maturity characters, a cultivar registration index model was developed to simplify the tedious calculation process in national cotton registration procedure, and thus to enhance the practical application of cultivar regis-tration index in cotton breeding and cotton recommending. [Method] By means of correlation analysis, partial correlation analysis and path analysis methods, the cor-relation of cotton main properties and their effects on cultivar registration index were explored using the dataset of national cotton regional trials in Yangtze River Val ey during 1996-2013. The cultivar registration index model was constructed with step-wise regression statistical technique to ascertain the quantitative relationship of main characters with cultivar registration index, and the regional cotton trial dataset in 2013 was used to validate the model. [Result] Several characters with larger deter-minants to cultivar registration index were screened out, i.e. lint yield increase ratio, pro-frost yield ratio, verticil ium wilt index, fiber strength, fusarium wilt index and mi-cronaire value. The cultivar registration index model defined the functional relation-ship of cultivar registration index with the selected main characters, among which lint yield increase ratio, fiber strength and micronaire value contributed most to culti-var registration index. The model validation with regional cotton trials in 2013 indi-cated the root mean square error, RMSE was only 2.77, and the variation coeffi-cient was 6.77%, which confirmed the model prediction effect was quite perfect. [Conclusion] The developed cultivar registration index model was reliable enough to simulate the complicated scoring system in cultivar registration procedure, also sim-plified cotton registration process, and enhanced the practicability of the cultivar reg-istration index.

  19. [Spatiotemporal change characteristics of agricultural climate resources in middle and lower reaches of Yangtze River].

    Science.gov (United States)

    Li, Yong; Yang, Xiao-guang; Dai, Shu-wei; Wang, Wen-feng

    2010-11-01

    The period 1961-2007 was divided into two by the time node of year 1981, and the change characteristics of the agricultural climate resources both in period I (1961-1980) and in period II (1981-2007) were analyzed and compared. The results showed that under the background of global warming, the average climatic trend rate of > or = 10 degrees C accumulated temperature in the middle and lower reaches of Yangtze River in temperature-defined growth season during 1961-2007 was 74 degrees C x d x 10 a(-1), and the > or =10 degrees C accumulated temperature in period II was 124 d higher than that in period I. Comparing with that in period I, the safe planting boundary of double cropping rice in period II moved 0.79 degrees northward. In 1961-2007, the precipitation in temperature-defined growth season had an overall increasing trend. Comparing with those in period I, the precipitation and the area of > or = 767 mm precipitation (water requirement for normal growth of double cropping rice) in period II were increased by 1.6% and 1.13 x 10(4) km2, respectively. The average sunshine hour in temperature-defined growth season in period II was reduced by 8.1%, comparing with that in period I. In recent 47 years, about 91.1% stations in the reaches showed a decreasing trend in sunshine hours. Comparing with that in period I, the reference crop evapotranspiration in temperature-defined growth season in period II showed a slightly decreasing trend, and its low value region expanded while its high value region narrowed. The beginning date of daily temperature over 10 degrees C was averagely 2 days earlier in period II than that in period I, while the ending date was in reverse. The ending date of daily temperature over 22 degrees C was almost the same in periods I and II. PMID:21361018

  20. Hydrologic risk analysis in the Yangtze River basin through coupling Gaussian mixtures into copulas

    Science.gov (United States)

    Fan, Y. R.; Huang, W. W.; Huang, G. H.; Li, Y. P.; Huang, K.; Li, Z.

    2016-02-01

    In this study, a bivariate hydrologic risk framework is proposed through coupling Gaussian mixtures into copulas, leading to a coupled GMM-copula method. In the coupled GMM-Copula method, the marginal distributions of flood peak, volume and duration are quantified through Gaussian mixture models and the joint probability distributions of flood peak-volume, peak-duration and volume-duration are established through copulas. The bivariate hydrologic risk is then derived based on the joint return period of flood variable pairs. The proposed method is applied to the risk analysis for the Yichang station on the main stream of the Yangtze River, China. The results indicate that (i) the bivariate risk for flood peak-volume would keep constant for the flood volume less than 1.0 × 105 m3/s day, but present a significant decreasing trend for the flood volume larger than 1.7 × 105 m3/s day; and (ii) the bivariate risk for flood peak-duration would not change significantly for the flood duration less than 8 days, and then decrease significantly as duration value become larger. The probability density functions (pdfs) of the flood volume and duration conditional on flood peak can also be generated through the fitted copulas. The results indicate that the conditional pdfs of flood volume and duration follow bimodal distributions, with the occurrence frequency of the first vertex decreasing and the latter one increasing as the increase of flood peak. The obtained conclusions from the bivariate hydrologic analysis can provide decision support for flood control and mitigation.

  1. Inorganic aerosols responses to emission changes in Yangtze River Delta, China.

    Science.gov (United States)

    Dong, Xinyi; Li, Juan; Fu, Joshua S; Gao, Yang; Huang, Kan; Zhuang, Guoshun

    2014-05-15

    The new Chinese National Ambient Air Quality standards (CH-NAAQS) published on Feb. 29th, 2012 listed PM2.5 as criteria pollutant for the very first time. In order to probe into PM2.5 pollution over Yangtze River Delta, the integrated MM5/CMAQ modeling system is applied for a full year simulation to examine the PM2.5 concentration and seasonality, and also the inorganic aerosols responses to precursor emission changes. Total PM2.5 concentration over YRD was found to have strong seasonal variation with higher values in winter months (up to 89.9 μg/m(3) in January) and lower values in summer months (down to 28.8 μg/m(3) in July). Inorganic aerosols were found to have substantial contribution to PM2.5 over YRD, ranging from 37.1% in November to 52.8% in May. Nocturnal production of nitrate (NO3(-)) through heterogeneous hydrolysis of N2O5 was found significantly contribute to high NO3(-) concentration throughout the year. In winter, NO3(-) was found to increase under nitrogen oxides (NOx) emission reduction due to higher production of N2O5 from the excessive ozone (O3) introduced by attenuated titration, which further lead to increase of ammonium (NH4(+)) and sulfate (SO4(2-)), while other seasons showed decrease response of NO3(-). Sensitivity responses of NO3(-) under anthropogenic VOC emission reduction was examined and demonstrated that in urban areas over YRD, NO3(-) formation was actually more sensitive to VOC than NOx due to the O3-involved nighttime chemistry of N2O5, while a reduction of NOx emission may have counter-intuitive effect by increasing concentrations of inorganic aerosols. PMID:24631615

  2. Waterbird Population Changes in the Wetlands at Chongming Dongtan in the Yangtze River Estuary, China

    Science.gov (United States)

    Ma, Zhijun; Wang, Yong; Gan, Xiaojing; Li, Bo; Cai, Yinting; Chen, Jiakuan

    2009-06-01

    We studied the changes in wetland habitats and waterbird communities between the 1980s and the 2000s at Chongming Dongtan, a Ramsar site in the Yangtze River estuary, an ecologically important region. This region is an important stopover site for shorebirds along the East Asian-Australasian flyway and is extensively used by waterfowl. A net loss of 11% of the wetland area was estimated during study periods at Chongming Dongtan. The change was dependent on wetland types: while the area of artificial habitats such as paddy fields and aquacultural ponds more than doubled, more than 65% of natural habitats including sea bulrush ( Scirpus mariqueter) and common reed ( Phragmites australis) marshes were lost over the two decades. An exotic plant species introduced from North America, smooth cordgrass ( Spartina alterniflora), occupied 30% of the vegetated intertidal zone by the 2000s. Although waterbird species richness did not change between the 1980s (110) and the 2000s (111), 13 species found in 1980s were replaced by 14 newly recorded species. Moreover, there were more species with declining trends (58) than with increasing trends (19). The population trends of species were affected by residential status and habitat types. Transients, wintering migrants, and habitat specialists were more likely to show declining trends compared to those breeding at Dongtan (including year-round and summer residents) and habitat generalists. Furthermore, species associated mainly with natural wetlands were more likely to decline than those associated mainly with artificial wetlands. These patterns suggest that the loss and change of wetland habitats at Chongming Dongtan adversely affected local population dynamics and might have contributed to the global decline of some waterbird species. Because Chongming Dongtan provides stopover and wintering habitats for many migratory waterbirds, protection and restoration of natural wetlands at Chongming Dongtan are urgently needed.

  3. Contamination of PAHs in Sludge Samples from the Yangtze River Delta Area

    Institute of Scientific and Technical Information of China (English)

    SHEN Rong-Yan; LUO Yong-Ming; ZHANG Gang-Ya; TENG Ying; LI Zhen-Gao; WU Long-Hua

    2007-01-01

    To ascertain the contaminated conditions of polycyclic aromatic hydrocarbons (PAHs) in sludge and to evaluate the risk of application of this sludge for agricultural purposes, 44 sludge samples obtained from 15 cities in the Yangtze River Delta area of China were investigated using capillary gas chromatography/mass spectrometry (GC/MS) after ultrasonic extraction and silica gel cleanup. PAHs' contents ranged from 0.0167 to 15.4860 mg kg-1 (dry weight, DW) and averaged 1.376 mg kg-1, with most samples containing<1.5 mg kg-1. Pyrene (PY), fluoranthene (FL), benzo[b]fluoranthene (BbF), indeno[1,2,3-cd]pyrene (IND), benzo[a]pyrene (B[a]P), and benzo[g,h,i]perylene (BghiP) were the most dominant compounds, ranging from 0.1582 to 0.2518 mg kg-1. Single PAH, such as naphthalene (NAP, 2-benzene rings), phenan-threne (PA, 3-benzene rings), PY (4-benzene rings), and FL (3-benzene rings), had high detection rates (76.1%-93.5%). The distribution patterns of PAHs were found to vary with the sludge samples; however, the patterns showed that a few compounds with 2- and 3-benzene rings were commonly found in the samples, whereas those with 4-, 5-, and 6-benzene rings were usually less commonly found. All the 44 sludge samples were within the B[a]P concentration limit for sludge applied to agricultural land in China (< 3.0 mg kg-1). The probable sources of PAH contamination in the sludge samples were petroleum, petroleum products, and combustion of liquid and solid fuel. The concentrations and distributions of the 16 PAHs in sludge were related to sludge type, source, and treatment technology, together with the physicochemical properties.

  4. Dynamics of the lakes in the middle and lower reaches of the Yangtze River basin, China, since late nineteenth century.

    Science.gov (United States)

    Cui, Lijuan; Gao, Changjun; Zhao, Xinsheng; Ma, Qiongfang; Zhang, Manyin; Li, Wei; Song, Hongtao; Wang, Yifei; Li, Shengnan; Zhang, Yan

    2013-05-01

    The middle and lower reaches of the Yangtze River basin have the most representative and largest concentration of freshwater lakes in China. However, the size and number of these lakes have changed considerably over the past century due to the natural and anthropogenic impact. The lakes, larger than 10 km(2) in size, were chosen from relief maps and remotely sensed images in 1875, 1950, 1970, 1990, 2000, and 2008 to study the dynamics of lakes in the middle and lower reaches of the Yangtze River basin and to examine the causes and consequences of these changes. Results indicated that there was a dramatic reduction in lake areas, which decreased by 7,841.2 km(2) (42.64 %) during the study period (1875-2008), and the number of lakes in this region changed moderately. Meanwhile, a large number of lakes in the middle and lower reaches of the Yangtze River basin were directly converted into paddy fields, ponds, building lands, or other land-use types over the study period. Therefore, all kinds of lake reclamation should be identified as the major driving factors for the loss of lake in this region. Furthermore, flooding, soil erosion, and sedimentation were also the main factors which triggered lake changes in different periods. Some wetland conservation and restoration projects have been implemented since the 1970s, but they have not reversed the lake degradation. These findings were of great importance to managers involved in making policy for the conservation of lake ecosystems and the utilization of lake resources. PMID:22965946

  5. Source, transport and impacts of a heavy dust event in the Yangtze River Delta, China, in 2011

    OpenAIRE

    X Fu; S. X. Wang; Cheng, Z; J. Xing; B. Zhao; Wang, J D; J. M. Hao

    2014-01-01

    Dust invasion is an important type of particle pollution in China. During 1 to 6 May in 2011, a dust event was observed in the Yangtze River Delta region (YRD). The highest PM10 (particles up to 10 μ in diameter) concentration reached over 1000 μg m−3 and the visibility was below 3 km. In this study, the Community Multi-scale Air Quality modeling system (CMAQ5.0) coupled with an in-line windblown dust model was used to simulate the formation, spatial and temporal characteris...

  6. Socioeconomic impacts of hydropower development on the Yibin-Chongqing section, upper reaches of the Yangtze River

    Science.gov (United States)

    Ma, Jing; Liu, Yu; Wang, Hao; Yan, Deng Hua; Lv, Ying Kang; Yang, Zhaohui

    The aim of this paper is to quantify the socioeconomic impacts of hydropower development to reflect its positive functions from multiple perspectives and dimensions. By applying the multi-regional Computable General Equilibrium (CGE) model to a case study of the Yibin-Chongqing section along the upper reaches of the Yangtze River, the analysis shows that hydropower development has outstanding benefits for the regional economy and livelihood improvement, as proved by various indicators including consumption, investment, GDP, employment, and income. Meanwhile, application of the CGE model provides an effective way to quantitatively assess the socioeconomic impact of hydropower and other clean energy development.

  7. Development and application of a water pollution emergency response system for the Three Gorges Reservoir in the Yangtze River, China.

    Science.gov (United States)

    He, Qiang; Peng, Shujuan; Zhai, Jun; Xiao, Haiwen

    2011-01-01

    There are many watercraft and production accidents in the Three Gorges Reservoir Area (TGRA) of the Yangtze River in China every year. Accidents threaten the water quality of the 1085 km2 surface area of the TGRA and millions of local people if oil and chemical leakage were to occur. A water pollution management system for emergency response (WPMS_ER) was therefore designed for the management of pollution in this area. An integrated geographic information system (GIS)-based water pollution management information system for the TGRA, called WPMS_ER_TGRA, was developed in this study. ArcGIS engine was used as the system development platform, and Visual Basic as the programming language. The models for hydraulic and water quality simulation and the generation of body-fitted coordinates were developed and programmed as a dynamically linked library file using Visual Basic, and they can be launched by other computer programs. Subsequently, the GIS-based information system was applied to the emergency water pollution management of a shipwreck releasing 10 tons of phenol into the Yangtze River during two hours. The results showed that WPMS_ER_TGRA can assist with emergency water pollution management and simulate the transfer and diffusion of accidental pollutants in the river. Furthermore, it can quickly identify the affected area and how it will change over time within a few minutes of an accident occurring. PMID:21793401

  8. Numerical Simulation of the Heavy Rainfall in the Yangtze-Huai River Basin during Summer 2003 Using the WRF Model

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-Bo

    2012-01-01

    In this study, a 47-day regional climate simulation of the heavy rainfall in the Yangtze-Huai River Basin during the summer of 2003 was conducted using the Weather Research and Forecast (WRY) model. The simulation reproduces reasonably well the evolution of the rainfall during the study period's three successive rainy phases, especially the frequent heavy rainfall events occurring in the Huai River Basin. The model captures the major rainfall peak observed by the monitoring stations in the morning. Another peak appears later than that shown by the observations. In addition, the simulation realistically captures not only the evolution of the low-level winds but also the characteristics of their diurnal variation. The strong southwesterly (low-level jet, LLJ) wind speed increases beginning in the early evening and reaches a peak in the morning; it then gradually decreases until the afternoon. The intense LLJ forms a strong convergent circulation pattern in the early morning along the Yangtze-Huai River Basin. This pattern partly explains the rainfall peak observed at this time. This study furnishes a basis for the further analysis of the mechanisms of evolution of the LLJ and for the further study of the interactions between the LLJ and rainfall.

  9. Development and application of a water pollution emergency response system for the Three Gorges Reservoir in the Yangtze River, China

    Institute of Scientific and Technical Information of China (English)

    Qiang He; Shujuan Peng; Jun Zhai; Haiwen Xiao

    2011-01-01

    There are many watercraft and production accidents in the Three Gorges Reservoir Area (TGRA) of the Yangtze River in China every year. Accidents threaten the water quality of the 1085 km2 surface area of the TGRA and millions of local people if oil and chemical leakage were to occur. A water pollution management system for emergency response (WPMS-ER) was therefore designed for the management of pollution in this area. An integrated geographic information system (GIS)-based water pollution management information system for the TGRA, called WPMS_ER_TGRA, was developed in this study. ArcGIS engine was used as the system development platform, and Visual Basic as the programming language. The models for hydraulic and water quality simulation and the generation of body-fitted coordinates were developed and programmed as a dynamically linked library file using Visual Basic, and they can be launched by other computer programs. Subsequently, the GIS-based information system was applied to the emergency water pollution management of a shipwreck releasing 10 tons of phenol into the Yangtze River during two hours. The results showed that WPMS_ER_TGRA can assist with emergency water pollution management and simulate the transfer and diffusion of accidental pollutants in the river. Furthermore, it can quickly identify the affected area and how it will change over time within a few minutes of an accident occurring.

  10. On regional differences of classic gardens in south of Changjiang River%浅析江南古典园林的地域差异

    Institute of Scientific and Technical Information of China (English)

    沈苏彦; 沙润

    2011-01-01

    Selecting the representative Suzhou gardens,Yangzhou gardens and Huizhou gardens in the classic gardens in south of Changjiang River,the paper analyzes the differences among the classic gardens in these areas from the address selection of gardens,the mountains,the water,and buildings,and explores the reasons of these differences from the regional natural environment,cultural background and the identity of owners,and achieves some beneficial conclusions.%选取江南古典园林中较有代表性的苏州园林、扬州园林和徽州园林,从园林选址和山、水、建筑等构园要素角度分析了各地古典园林的差异,在此基础上从地域自然环境、文化背景和园主身份三方面探究了这些差异产生的原因,得出了一些富有指导意义的结论。

  11. Absorption coefficient of urban aerosol in Nanjing, west Yangtze River Delta, China

    Science.gov (United States)

    Zhuang, B. L.; Wang, T. J.; Liu, J.; Ma, Y.; Yin, C. Q.; Li, S.; Xie, M.; Han, Y.; Zhu, J. L.; Yang, X. Q.; Fu, C. B.

    2015-12-01

    Absorbing aerosols can significantly modulate short-wave solar radiation in the atmosphere, affecting regional and global climate. The aerosol absorption coefficient (AAC) is an indicator that assesses the impact of absorbing aerosols on radiative forcing. In this study, the near-surface AAC and absorption Ångström exponent (AAE) in the urban area of Nanjing, China, are characterized on the basis of measurements in 2012 and 2013 using the seven-channel Aethalometer (model AE-31, Magee Scientific, USA). The AAC is estimated with direct and indirect corrections, which result in consistent temporal variations and magnitudes of AAC at 532 nm. The mean AAC at 532 nm is about 43.23 ± 28.13 M m-1 in the urban area of Nanjing, which is much lower than that in Pearl River Delta and the same as in rural areas (Lin'an) in Yangtze River Delta. The AAC in the urban area of Nanjing shows strong seasonality (diurnal variations); it is high in cold seasons (at rush hour) and low in summer (in the afternoon). It also shows synoptic and quasi-2-week cycles in response to weather systems. Its frequency distribution follows a typical log-normal pattern. The 532 nm AAC ranging from 15 to 65 M m-1 dominates, accounting for more than 72 % of the total data samples in the entire study period. Frequent high pollution episodes, such as those observed in June 2012 and in winter 2013, greatly enhanced AAC and altered its temporal variations and frequency distributions. These episodes are mostly due to local emissions and regional pollution. Air masses flowing from northern China to Nanjing can sometimes be highly polluted and lead to high AAC at the site. AAE at 660/470 nm from the Schmid correction (Schmid et al., 2006) is about 1.56, which might be more reasonable than from the Weingartner correction (Weingartner et al., 2003). Low AAEs mainly occur in summer, likely due to high relative humidity (RH) in the season. AAC increases with increasing AAE at a fixed aerosol loading. The RH

  12. Projection of Future Precipitation Extremes Change(2001-2050)in the Yangtze River Basin%2050年前长江流域极端降水预估

    Institute of Scientific and Technical Information of China (English)

    张增信; 张强; 张金池

    2008-01-01

    Daily maximum rainfall(R1D)was higher in the Jialing River basin,the Taihu Lake area and the mid-lower main stream section of the Yangtze River basin in the 1990s,and there was a good relationship between ECHAM5/MPI-OM model simulation and the observed data about extreme precipitation(R1D).Under the IPCC SRES A2,A1B,and B1 scenarios,R1Ds are all projected to be in increasing trends in the upper Yangtze River basin during 2001-2050,and R1D shows a more significant increasing tendency under the A2 scenario when compared with the A1B scenario before 2020.With respect to the middle and lower Yangtze River basin,an increasing tendency is projected before 2025,and since then the increasing tendency will become insignificant.There might be more floods to the south of the Yangtze River and more droughts to the north in the next decades.

  13. Does reservoir always decrease flood risk? A case study of the Three Gorges Reservoir for middle Yangtze River

    Science.gov (United States)

    Liu, P.; Liu, Y.

    2014-12-01

    This study is aimed to quantify the effects of the hydrologic alteration of the middle Yangtze River due to the operation of the Three Gorges Reservoir (TGR), the largest dam in China. The streamflows of three downstream stations, Yichang, Shashi and Luoshan are studied to quantify the effect of TGR. Three schemes, including without TGR operation, with conventional and optimal TGR operating rules respectively, are compared of the Yichang station. The multi-input single-output systems models (MISO) are used to simulate the streamflows at Shashi and Luoshan stations with three different inputs of Yichang station, respectively. These streamflows are then analyzed by using the Indicators of Hydrologic Alteration (IHA) and the Range of Variability Approach (RVA) to evaluate the hydrologic changes associated with TGR operation. Results indicate that: (1) The 1-day maximum flows of Yichang and Shashi stations are decreased significantly, while their 1-day minimum flows are increased with TGR operation. (2) On the contrary with the maximum flows at Yichang and Shashi stations, the 1-day maximum flow of Luoshan station can be increased caused by encountering between the intervening flood and the post-flood release of the TGR. These findings are beneficial to evaluate the hydrologic systems in the middle Yangtze River after the TGR construction, and provide a scientific foundation for deriving the TGR flood control rules.

  14. Temporal and spatial distribution of red tide outbreaks in the Yangtze River Estuary and adjacent waters, China.

    Science.gov (United States)

    Liu, Lusan; Zhou, Juan; Zheng, Binghui; Cai, Wenqian; Lin, Kuixuan; Tang, Jingliang

    2013-07-15

    Between 1972 and 2009, evidence of red tide outbreaks in the Yangtze River Estuary and adjacent waters was collected. A geographic information system (GIS) was used to analyze the temporal and spatial distribution of these red tides, and it was subsequently used to map the distribution of these events. The results show that the following findings. (1) There were three red tide-prone areas: outside the Yangtze River Estuary and the eastern coast of Sheshan, the Huaniaoshan-Shengshan-Gouqi waters, and the Zhoushan areas and eastern coast of Zhujiajian. In these areas, red tides occurred 174 total times, 25 of which were larger than 1000 km(2) in areal extent. After 2000, the frequency of red tide outbreaks increased significantly. (2) During the months of May and June, the red tide occurrence in these areas was 51% and 20%, respectively. (3) Outbreaks of the dominant red tide plankton species Prorocentrum dong-haiense, Skeletonema costatum, Prorocentrum dantatum, and Noctiluca scientillan occurred 38, 35, 15, and 10 times, respectively, during the study interval. PMID:23628547

  15. Tracking historical lead pollution in the coastal area adjacent to the Yangtze River Estuary using lead isotopic compositions

    International Nuclear Information System (INIS)

    The rapid economic development in the Yangtze River Delta (YRD), China in the last three decades has had a significant impact on the environment of the East China Sea (ECS). Lead isotopic compositions of a 210Pb dated sediment core collected from the coastal ECS adjacent to the Yangtze River Estuary were analyzed to track the Pb pollution in the region. The baseline Pb concentration in the coastal ECS sediments before the industrialization in China was 32 μg g-1, and the corresponding 206Pb/207Pb ratio was 1.195. The high-resolution profiles of Pb flux and 206Pb/207Pb ratios had close relationships with the economic development and the history of the use of leaded gasoline in China, and they were clearly different from those of most European countries and United States. - The combination of Pb concentration, sedimentary flux, Pb isotopic composition and 210Pb dating in the coastal ECS sediments revealed the historical Pb pollution in China

  16. Assessment of Soil Water Content in Field with Antecedent Precipitation Index and Groundwater Depth in the Yangtze River Estuary

    Institute of Scientific and Technical Information of China (English)

    XIE Wen-ping; YANG Jing-song

    2013-01-01

    To better understand soil moisture dynamics in the Yangtze River Estuary (YRE) and predict its variation in a simple way, a field monitoring experiment was carried out along the north branch of the Yangtze River, where seawater intrusion was strong and salt-water variation is one of the limiting factors of local agriculture. In present paper, relation between antecedent precipitation index (API) and soil water content is studied, and effects of groundwater depth on soil water content was analyzed. A relatively accurate prediction result of soil water content was reached using a neural network model. The impact analysis result showed that the variation of the API was consistent with soil water content and it displayed significant correlations with soil water content in both 20 and 50 cm soil layer, and higher correlation was observed in the layer of 20 cm. Groundwater impact analysis suggested that soil moisture was affected by the depth of groundwater, and was affected more greatly by groundwater at depth of 50 cm than that at 20 cm layer. By introducing API, groundwater depth and temperature together, a BP artificial network model was established to predict soil water content and an acceptable agreement was achieved. The model can be used for supplementing monitoring data of soil water content and predicting soil water content in shallow groundwater areas, and can provide favorable support for the research of water and salt transport in estuary area.

  17. Role of sectoral and multi-pollutant emission control strategies in improving atmospheric visibility in the Yangtze River Delta, China

    International Nuclear Information System (INIS)

    The Community Multi-scale Air Quality modeling system is used to investigate the response of atmospheric visibility to the emission reduction from different sectors (i.e. industries, traffic and power plants) in the Yangtze River Delta, China. Visibility improvement from exclusive reduction of NOx or VOC emission was most inefficient. Sulfate and organic aerosol would rebound if NOx emission was exclusively reduced from any emission sector. The most efficient way to improve the atmospheric visibility was proven to be the multi-pollutant control strategies. Simultaneous emission reductions (20–50%) on NOx, VOC and PM from the industrial and mobile sectors could result in 0.3–1.0 km visibility improvement. And the emission controls on both NOx (85%) and SO2 (90%) from power plants gained the largest visibility improvement of up to 4.0 km among all the scenarios. The seasonal visibility improvement subject to emission controls was higher in summer while lower in the other seasons. -- Highlights: • Atmospheric visibility in the Yangtze River Delta is modeled and evaluated. • Responses of visibility changes to various emission reduction scenarios are compared. • Sulfate aerosol will increase if only NOx emission is reduced. • The multi-pollutant control strategy is most efficient for improving visibility. -- Responses of visibility changes to various emission reduction scenarios are compared. The multi-pollutant control strategy is most efficient for improving visibility in YRD, China

  18. Prediction and prevention of the impacts of sea level rise on the Yangtze River Delta and its adjacent areas

    Institute of Scientific and Technical Information of China (English)

    施雅风; 朱季文; 谢志仁; 季子修; 蒋自巽; 杨桂山

    2000-01-01

    The Yangtze River Delta region is characterized by high density of population and rapidly developing economy. There are low lying coastal plain and deltaic plain in this region. Thus, the study area could be highly vulnerable to accelerated sea level rise caused by global warming. This paper deals with the scenarios of the relative sea level rise in the early half period of the 21st century in the study area. The authors suggested that relative sea level would rise 25-50 cm by the year 2050 in the study area, of which the magnitude of relative sea level rise in the Yangtze River Delta would double the perspective worldwide average. The impacts of sea level rise include: (i) exacerbation of coastline recession in several sections and vertical erosion of tidal flat, and increase in length of eroding coastline; (ii) decrease in area of tidal flat and coastal wetland due to erosion and inundation; (iii) increase in frequency and intensity of storm surge, which would threaten the coastal protection works; (i

  19. Satellite remote sensing of water resources in the Yangtze and Yellow Rivers of China based on infrared imagery of cloud distributions

    Science.gov (United States)

    Hung, R. J.; Dodge, James C.

    1990-01-01

    Although the two largest rivers in China originate in the same region, separated only by the Bayanhar Mountains as a watershed, the Yangtze and Yellow Rivers behave in quite different ways. Most of the warm and humid air currents from the Arabian Sea and Bay of Bengal are blocked by the Bayanhar Mountains. As a result, the amount of water in the Yellow River is only 5 percent of that in the Yangtze River. Based on the cloud coverage area and the cloud volumetric distributions, and also the thickness above 9.4 kms of the cumulus clouds located north and south of the Bayanhar Mountains, from GEO satellite IR imagery, the results suggest that a more detailed investigation is warranted in the hope that the proper modification of cumuli north of the Bayanhar Mountains would enhance the rainfall over the fountainhead of the Yellow River.

  20. Relationship between precipitation and the infiltration depth over the middle and lower reaches of the Yellow River and Yangtze-Huaihe River Valley

    Institute of Scientific and Technical Information of China (English)

    Zhixin Hao; Jingyun Zheng; Quansheng Ge; Xifeng Guo

    2008-01-01

    The purpose of the paper iS to extract and make the best use of rainfall information contained in the Chinese historical archives of Qing Dynasty,and reconstruct the precipitation series during 1736-1911.The study followed the Yu-Fen-Cun(rainfall infiltration depth)observation method in Qing Dynasty,to conduct soil infiltration experiment under the natural rainfall conditions during 2004-2006.The related parameters,such as precipitation,intensity,initial soil moisture content and infiltration depth have been measured at 10 stations (east of 105°E,30°-40°N)with representative climatic conditions and soil physical texture in the middle and lower reaches of the Yellow River and Yangtze-Huaihe River Valley.The statistical results indicate that precipitation is the primary influencing factor to infiltration depth and is positively correlated with the infiltration depth.Additionally,the effects of every factor On infiltration depth are significantly difierent between the middle and lower reaches of the Yellow River and Yangtze-Huaihe River Valley.Finally,the relationship equations of precipitation and infiltration depth are established for each site,most of which can pass over 60%of the variance explanations and provide quantitative models to reconstruct the precipitation series using Yu-Fen-Curt records in Qing Dynasty.

  1. Evapotranspiration Estimation over Yangtze River Basin from GRACE satellite measurement and in situ data

    Science.gov (United States)

    Li, Qiong; Luo, Zhicai; Zhong, Bo; Wang, Haihong; Zhou, Zebing

    2016-04-01

    As the critical component of hydrologic cycle, evapotranspiration (ET) plays an important role in global water exchanges and energy flow across the hydrosphere, atmosphere and biosphere. Influenced by the Asian monsoon, the Yangtze River Basin (YRB) suffer from the several severe floods and droughts over the last decades due to the significant difference between temporal and spatial distribution terrestrial water storages. As an indispensable part, it is practically important to assessment ET in the YRB accompany with increased population and rapid economic and agriculture development. Average ET over the YRB is computed as the residual of terrestrial water budget using the Gravity Recovery and Climate Experiment (GRACE) satellite-based measurements and the ground-based observations. The GRACE-based ET were well coincidence with the ET from MODIS, with the correlation coefficient of 0.853, and the correlation coefficient is 0.696 while comparing with the ET ground-based observation. The mean monthly average of ET from these various estimates is 56.9 mm/month over the whole YRB, and peak between June and August. Monthly variations of ET reach a maximum in Wujiang with 69.11 mm/month and a minimum in Jinshajiang with 39.01 mm/month. Based on the correlation between ET and independent estimates of near-surface temperature and soil moisture, it is showed that as the temperature increased, the ET of the seven sub-catchment were rising except for the Poyang Lake and Donting Lake. And we also can infer that the midstream of YRB is significant correlated with ESON especially in the Hanjiang basin. The Surface Humidity Index over the YRB was gradually decreased and its variations in each sub-catchment showed a significant decreasing trend in Jinshajiang and Mingjiang. This research has important potential for use in large-scale water budget assessments and intercomparison studies. Acknowledgements: This research is supported by the National Natural Science Foundation of

  2. Seasonal variation of urban carbonaceous aerosols in a typical city Nanjing in Yangtze River Delta, China

    Science.gov (United States)

    Li, Bing; Zhang, Jie; Zhao, Yu; Yuan, Siyu; Zhao, Qiuyue; Shen, Guofeng; Wu, Haisuo

    2015-04-01

    The Yangtze River Delta (YRD) is one of the regions with the most dynamic economy and severe atmospheric pollution in China. In order to characterize the particle features, especially the carbonaceous component in the YRD, particulate matter smaller than 2.5 μm (PM2.5) and 10 μm (PM10) samples in each season were collected in urban Nanjing, a typical city that locates in the west part of the YRD. The organic carbon (OC) and elemental carbon (EC) was differentiated using the thermal optical reflectance method. The average concentrations of PM2.5, OC and EC during the study periods were observed to be 117.6, 13.8, and 5.3 μg/m3 respectively, with all the highest levels in winter. The mass fraction of the Total carbonaceous aerosol (TCA) in PM2.5 was estimated at 23% on average, lower than those reported for other cities in the YRD. The OC and EC correlated well in all the seasons, especially in spring and winter, implying that OC and EC were attributed to common emission sources. Good correlation was observed between OC and estimated K+ from biomass burning in the harvest season in autumn and summer, indicating biomass burning a significant source of carbonaceous aerosols. This could also be confirmed by the lower fraction of OC3 + OC4 in OC during autumn and summer. The secondary organic carbon (SOC) estimated by EC-tracer method was the highest in winter (7.3 μg/m3) followed by autumn (6.7 μg/m3), summer (3.7 μg/m3) and spring (2.0 μg/m3). However, the SOC/OC in winter was not as high as that in summer and autumn, implying the high concentration of OC in winter was probably due to the stable weather but not mainly caused by SOC formation. The high SOC/OC ratio in summer was attributed to stronger oxidation, which could be suggested by higher sulfur oxidation ratio (SOR).

  3. Observations of relative humidity effects on aerosol light scattering in the Yangtze River Delta of China

    Science.gov (United States)

    Zhang, L.; Sun, J. Y.; Shen, X. J.; Zhang, Y. M.; Che, H. C.; Ma, Q. L.; Zhang, Y. W.; Zhang, X. Y.; Ogren, J. A.

    2015-01-01

    Scattering of solar radiation by aerosol particles is highly dependent on relative humidity (RH) as hygroscopic particles take up water with increasing RH. To achieve a better understanding of the effect of aerosol hygroscopic growth on light scattering properties and radiative forcing, a field campaign was carried out in the Yangtze River Delta of China in March 2013. During the observation period, the mean and standard deviation of enhancement factors at RH=85% for the scattering coefficient (f(85%)), backscattering coefficient (fb(85%)) and hemispheric backscatter fraction (fβ(85%)) were 1.58 ± 0.12, 1.25 ± 0.07 and 0.79 ± 0.04, respectively, i.e. aerosol scattering coefficient and backscattering coefficient increased by 58 and 25% as the RH increased from 40 to 85%. Meanwhile, the aerosol hemispheric backscatter fraction decreased by 21%. The relative amount of organic matter (OM) and inorganics in PM1 was found to be a main factor determining the magnitude of f(RH), the highest values of f(RH) corresponded to the aerosols with a small fraction of organic matter (OM), and vice versa. The relative amount of NO3- in fine particles was strongly correlated to f(85%), which suggests NO3- played a vital role in aerosol hygroscopic growth during this study. The mass percentage of nitrate also had a close relation to the curvature of humidograms, namely, the higher the nitrate concentration is, the straighter the humidogram will be. Air masses that arrived at LinAn in March can be classified into northerly-polluted, locally-polluted and dust-influenced types, the scattering enhancement factors at 85% RH were 1.52 ± 0.10, 1.64 ± 0.09 and 1.48 ± 0.05, respectively. The sensitivity of the aerosol radiative forcing to f(RH) at the measured mean ambient RH 67% for various aerosol types was also estimated. The direct radiative forcing increased by 11.8, 19.5, and 10.5%, respectively, for locally-polluted, northerly-polluted and dust-influenced aerosols due to aerosol

  4. A STUDY ON THE EQUILIBRIUM PROFILE FOR THE LUOSHAN-HANKOU REACH IN THE MIDDLE YANGTZE RIVER

    Institute of Scientific and Technical Information of China (English)

    Jinyun DENG; Yitian LI

    2003-01-01

    Based on the morphology of the Luoshan-Hankou reach in the middle Yangtze River, the one dimensional (1 -D), unsteady flow and sediment transport model was applied to study the river channel equilibrium profile.Meanwhile, a simple theoretical model relating the equilibrium profile and the incoming flow and sediment from the upper reach was developed. The numerical simulation results of the 1-D model were compared with the corresponding results of the theoretical model with reasonable agreement found between the two models.Finally, the equilibrium slope variations and their effects on flood control in response to the changes in the sediment transport process because of the Three Gorges Reservoir were analyzed using the 1-D model.

  5. [Pollution status of phenolic compounds in the soil and sediment from a chemical industrial park along the Yangtze River].

    Science.gov (United States)

    Chen, Jiexia; Wei, Enze; Xian, Qiming

    2014-08-01

    A determination method of 12 phenolic compounds in soil and sediment samples by gas chromatography-mass spectrometry (GC-MS) analysis coupled with accelerated solvent extraction (ASE) and gel permeation chromatography (GPC) for clean-up was developed. The method detection limits (MDLs) varied from 0. 410 μg/kg to 13. 1 μg/kg (dry weight), and the average recoveries ranged from 70. 7% to 122% with the relative standard deviations (RSDs) of 1. 2% to 16%. Based on this method, the levels of 12 phenolic compounds were investigated in 17 soil surrounding a chemical industrial park along the Yangtze River and seven sediment samples collected in the river. It was found that 11 of the 12 phenolic compounds were detected in all of the 24 samples, and only hydroquinone was below the MDL. The contents of the total 12 phenolic compounds were 10. 16-30. 66 mg/kg in the soil and 18. 00-29. 83 mg/kg in the sediment, with the average contents of 18. 26 and 22. 51 mg/kg respectively. It showed that 4-nitro- phenol, 4-chloro-3-methylphenol, 2-chlorohydroquinone, 2-methyl-4,6-dinitrophenol and 2,4,6- trichlorophenol were five major phenolic contaminants in the soil and sediment in this study. The pollution levels of the 12 phenolic compounds were low in the soil of the chemical industrial park as well as in the sediment of the Yangtze River, which implied a comparatively low risk for the environment. PMID:25434120

  6. Capability of TMPA products to simulate streamflow in upper Yellow and Yangtze River basins on Tibetan Plateau

    Directory of Open Access Journals (Sweden)

    Zhen-chun HAO

    2014-07-01

    Full Text Available Due to the high elevation, complex terrain, severe weather, and inaccessibility, direct meteorological observations do not exist over large portions of the Tibetan Plateau, especially the western part of it. Satellite rainfall estimates have been very important sources for precipitation information, particularly in rain gauge-sparse regions. In this study, Tropical Rainfall Measuring Mission (TRMM Multi-satellite Precipitation Analysis (TMPA products 3B42, RTV5V6, and RTV7 were evaluated for their applicability to the upper Yellow and Yangtze River basins on the Tibetan Plateau. Moreover, the capability of the TMPA products to simulate streamflow was also investigated using the Variable Infiltration Capacity (VIC semi-distributed hydrological model. Results show that 3B42 performs better than RTV5V6 and RTV7, based on verification of the China Meteorological Administration (CMA observational precipitation data. RTV5V6 can roughly capture the spatial precipitation pattern but overestimation exists throughout the entire study region. The anticipated improvements of RTV7 relative to RTV5V6 have not been realized in this study. Our results suggest that RTV7 significantly overestimates the precipitation over the two river basins, though it can capture the seasonal cycle features of precipitation. 3B42 shows the best performance in streamflow simulation of the abovementioned satellite products. Although involved in gauge adjustment at a monthly scale, 3B42 is capable of daily streamflow simulation. RTV5V6 and RTV7 have no capability to simulate streamflow in the upper Yellow and Yangtze River basins.

  7. Land-cover changes and its impacts on ecological variables in the headwaters area of the Yangtze River, China.

    Science.gov (United States)

    Wang, Genxu; Wang, Yibo; Kubota, Jumpei

    2006-09-01

    Land cover changes affect ecological landscape spatial pattern, and evolving landscape patterns inevitably cause an evolution in ecosystem functionality. Various ecological landscape variables, such as biological productivity (plant biomass and stock capacity), soil nutrients (organic matter and N content) and water source conservation capacity are identified as landscape function characteristics. A quantitative method and digital model for analyzing evolving landscape functionality in the headwaters areas of the Yangtze River, China were devised. In the period 1986-2000, patch transitions of the region's evolving landscapes have been predominantly characterized by alpine cold swamp meadow, with the highest coverage tending to be steppified meadow or steppe, and desertification landscape such as sand and bare rock land expansion. As the result of such changes, alpine swamp areas decreased by 3.08 x 10(3) km2 and the alpine cold sparse steppe and bare rock and soil land increased by 6.48 x 10(3) km2 and 5.82 x 10(3) km2, respectively. Consequently, the grass biomass production decreased by 2627.15 Gg, of which alpine cold swamp meadows accounted for 55.9% of this loss. The overall stock capacity of the headwaters area of the Yangtze River decreased by 920.64 thousand sheep units, of which 502.02 thousand sheep units decreased in ACS (Alpine cold swamp) meadow transition. Soil organic matter and N contents decreased significantly in most alpine cold meadow and swamp meadow landscape patches. From 1986 to 2000 the total losses of soil organic matter and total N in the entire headwaters region amounted to 150.2 Gkg and 7.67 Gkg. Meanwhile, the landscape soil water capacity declined by 935.9 Mm3, of which 83.9% occurred in the ACS meadow transition. In the headwater area of the Yangtze River, the complex transition of landscape resulted in sharp eco-environmental deterioration. The main indication for these changes involved the intensity of the climate in this region is

  8. 鄱阳湖水文节律变化及其与江湖水量交换的关系%Temporal Variation of Hydrological Rhythm in Poyang Lake and the Associated Water Exchange with the Changjiang River

    Institute of Scientific and Technical Information of China (English)

    戴雪; 万荣荣; 杨桂山; 王晓龙

    2014-01-01

    Watershed hydrological cycle has been changed along with the intensifying frequency of extreme wa-ter events due to the influence of climate change and human activities. Poyang Lake, the largest freshwater lake in China, is a lake naturally connected with the Changjiang River. The complicated river-lake interactions im-pact the hydrological rhythm of lake, which will further influence water security associated with flood control, drinking water usage, water pollution and water ecology in the lake basin. In the case, it is of great importance for maintaining watershed water security to understand the characteristics of hydrological rhythm variation in terms of river-lake interactions. In this study, temporal variation of hydrological rhythm in Poyang Lake and the associated water exchange with the Changjiang River were analyzed based on the measured hydrological data of 4 gauge stations in Poyang Lake area along with other data from the Hukou station at the intersection be-tween the Changjiang River and Poyang Lake in 1951-2011. The major findings are shown as follows:the span of dry season increased since water level remains low in November and April. Meanwhile, the span of flood sea-son decreased in 2000s. The lower water level in rising season and retreating season make Poyang Lake rising later but falling earlier than they did in 1980-2002, thus shortening the conversion time of the lake from flood situation to dry situation. Further, the peak flow in the annual hydrograph has been shifted. The primary cause of hydrological rhythm variation is the water exchange between the main stream of the Changjiang River and Poyang Lake. In 2000s, changes in the water level of the Changjiang River altered the interaction between the river and Poyang Lake through the slope of water surface, disturbing the lake basin hydrological processes and resulted in disordering of hydrological rhythm in Poyang Lake. The increasing discharge from the lake to the river in retreating

  9. Sustainable Urban Development and Land Use Change—A Case Study of the Yangtze River Delta in China

    Directory of Open Access Journals (Sweden)

    Haiyan Zhang

    2011-07-01

    Full Text Available This paper introduces a sustainability assessment method for the rapidly urbanizing Yangtze River Delta in China addressing the role of land use pattern. We first calculated the sustainability component scores of 16 cities in the area in 2000 and 2005. The results showed that socioeconomic and environmental conditions improved while the performance of resource-use degraded from 2000 to 2005. We then made a spatial analysis of land use change (LUC using geographic information systems during 1990–2000. We found that diverse spatiotemporal transformation occurred among the cities and identified urban development cluster patterns and profiles based on development density. Finally, we examined the impact of LUC on sustainable urban development (SUD. Using regression techniques, we demonstrated that urbanization, infrastructure development, industrial structure and income significantly affected environmental performance and resource-use. These results suggest a moderate pace of LUC with steady economic growth being key to SUD.

  10. Analogue-dynamical Prediction of Numerical Model Errors in the Mid-Lower Reaches of the Yangtze River

    CERN Document Server

    Wang, Qiguang; Feng, Guolin; Zheng, Zhihai

    2011-01-01

    A new prediction error correction scheme based on 74 circulation characteristics data provided by Weather Diagnostic Forecasting Division of National Climate Center, which is designed to develop the Operational Numerical Forecast Model (ONFM) of the National Climate Center of China, and the skill level of the precipitation prediction for rainy season in the midlower reaches (MLR) of the Yangtze River by ONFM is obviously raised. The approach use principal component(PC) analysis to prediction error of ONFM. And we used different factors to correct the different PCs of the error of precipitation field. The comparative study results indicate that the effectiveness of the new analogue error correction (AEC) scheme is better than system error correction (SEC) scheme.

  11. Ordered network structure and its prediction for the big floods in the Changjiang River Basin%长江流域大洪水有序网络结构及其预测研究

    Institute of Scientific and Technical Information of China (English)

    门可佩

    2014-01-01

    根据1827年以来的统计资料进行分析,长江流域大洪水展示出极为显著的有序性。运用翁文波信息预测理论,构建长江大洪水二维平面和三维立体信息有序网络结构并进行综合分析和预测,结果表明:2014、2020、2030、2036、2051与2058年前后的汛期,长江流域将有可能发生大洪水。%According to the latest statistical data of hydrology,a total of 21 floods took place in the Changjiang Riv-er Basin from 1827 to now,which showed a very obvious orderliness.Based on the information forecasting theory and ordered network analysis,we construct the 2D-and 3D-ordered network structure and make prediction research.Pre-diction results show that the future big deluges will probably occur in the Changjiang River Basin around 2014, 2020,2030,2036,2051 and 2058.

  12. A century-scale, human-induced ecohydrological evolution of wetlands of two large river basins in Australia (Murray) and China (Yangtze)

    Science.gov (United States)

    Kattel, Giri R.; Dong, Xuhui; Yang, Xiangdong

    2016-06-01

    Recently, the provision of food and water resources of two of the world's largest river basins, the Murray and the Yangtze, has been significantly altered through widespread landscape modification. Long-term sedimentary archives, dating back for some centuries from wetlands of these river basins, reveal that rapid, basin-wide development has reduced the resilience of biological communities, resulting in considerable decline in ecosystem services, including water quality. Large-scale human disturbance to river systems, due to river regulation during the mid-20th century, has transformed the hydrology of rivers and wetlands, causing widespread modification of aquatic biological communities. Changes to cladoceran zooplankton (water fleas) were used to assess the historical hydrology and ecology of three Murray and Yangtze river wetlands over the past century. Subfossil assemblages of cladocerans retrieved from sediment cores (94, 45, and 65 cm) of three wetlands: Kings Billabong (Murray), Zhangdu, and Liangzi lakes (Yangtze), showed strong responses to hydrological changes in the river after the mid-20th century. In particular, river regulation caused by construction of dams and weirs together with river channel modifications, has led to significant hydrological alterations. These hydrological disturbances were either (1) a prolonged inundation of wetlands or (2) reduced river flow, both of which caused variability in wetland depth. Inevitably, these phenomena have subsequently transformed the natural wetland habitats, leading to a switch in cladoceran assemblages to species preferring poor water quality, and in some cases to eutrophication. The quantitative and qualitative decline of wetland water conditions is indicative of reduced ecosystem services, and requires effective restoration measures for both river basins which have been impacted by recent socioeconomic development and climate change.

  13. The study of emission inventory on anthropogenic air pollutants and VOC species in the Yangtze River Delta region, China

    Directory of Open Access Journals (Sweden)

    C. Huang

    2011-01-01

    Full Text Available The purpose of this study is to develop an emission inventory for major anthropogenic air pollutants and VOC species in the Yangtze River Delta (YRD region for the year 2007. A "bottom-up" methodology was adopted to compile the inventory based on major emission sources in the sixteen cities of this region. Results show that the emissions of SO2, NOx, CO, PM10, PM2.5, VOCs, and NH3 in the YRD region for the year 2007 are 2391.8 kt, 2292.9 kt, 6697.1 kt, 3115.7 kt, 1510.8 kt, 2767.4 kt, and 458.9 kt, respectively. Ethylene, mp-xylene, o-xylene, toluene, and 1,2,4-trimethylbenzene, 2,4-dimethylpentane, ethyl benzene, propylene, 1-pentene, and isoprene are the key species contributing 77% to the total OFPs. The spatial distribution of the emissions shows the emissions and OFPs are mainly concentrated in the urban and industrial areas along the Yangtze River and around the Hangzhou Bay. The industrial sources including power plant, other fuel combustion facilities, and non-combustion processes contribute about 97%, 86%, 89%, 91%, and 69% of the total SO2, NOx, PM10, PM2.5, and VOC emissions. Vehicles take up 12.3% and 12.4% of the NOx and VOC emissions, respectively. Regarding OFPs, chemical industry, domestic use of paint and printing, and gasoline vehicle contribute 38.2%, 23.9%, and 11.6% to the ozone formation in the YRD region.

  14. Changes in monthly flows in the Yangtze River, China - With special reference to the Three Gorges Dam

    Science.gov (United States)

    Chen, Jing; Finlayson, Brian L.; Wei, Taoyuan; Sun, Qianli; Webber, Michael; Li, Maotian; Chen, Zhongyuan

    2016-05-01

    Much has been written on the hydrology of the Yangtze River in China, especially since the construction of the Three Gorges Dam. Given the range of views in the literature on the impacts of dams and other natural and anthropogenic activities in the catchment on monthly flows, we here set out to analyse the behavior of monthly flows over the period of record 1955-2014. In the literature, the Three Gorges dam has been singled out for particular comment, mostly adverse. In this paper we analyse trend in temperature, precipitation and discharge of the Yangtze River at the monthly time scale over a period that includes the 11 years since the Three Gorges Dam came into operation. The results show that for the upper basin, there has been a marked increase in discharge in the low flow months of January to March that began abruptly in 2003 and an abrupt decrease in flow in October at the same time. Similar changes are found for discharge from the lower basin but in that case the changes have occurred gradually over the period of record. These changes are the outcome of the operation of hydroelectric and flood control dams that have been built continuously in the lower basin since 1955 while in the upper basin the building of the Three Gorges Dam began a phase of rapid dam building not seen in the lower basin. The decreased flows in the late summer and autumn are not of sufficient magnitude to cause any problems for navigation or water supply. The enhanced flows in the winter low flow period are beneficial in that they reduce the likelihood of salt water intrusions in the estuary adversely affecting the supply of freshwater to Shanghai.

  15. The Mesoscale Heavy Rainfall Observing System (MHROS) over the middle region of the Yangtze River in China

    Science.gov (United States)

    Cui, Chunguang; Wan, Rong; Wang, Bin; Dong, Xiquan; Li, Hongli; Wang, Xiaokang; Xu, Guirong; Wang, Xiaofang; Wang, Yehong; Xiao, Yanjiao; Zhou, Zhimin; Fu, Zhikang; Wan, Xia; Zhang, Wengang; Peng, Tao; Leng, Liang; Stenz, Ronald; Wang, Junchao

    2015-10-01

    The Mesoscale Heavy Rainfall Observing System (MHROS), supported by the Institute of Heavy Rain (IHR), Chinese Meteorology Administration, is one of the major systems to observe mesoscale convective systems (MCSs) over the middle region of the Yangtze River in China. The IHR MHROS consists of mobile C-POL and X-POL precipitation radars, millimeter wavelength cloud radar, fixed S-band precipitation radars, GPS network, microwave radiometers, radio soundings, wind profiler radars, and disdrometers. The atmospheric variables observed or retrieved by these instruments include the profiles of atmospheric temperature, moisture, wind speed and direction, vertical structures of MCS clouds and precipitation, atmospheric water vapor, and cloud liquid water. These quality-controlled observations and retrievals have been used in mesoscale numerical weather prediction to improve the accuracy of weather forecasting and MCS research since 2007. These long-term observations have provided the most comprehensive data sets for researchers to investigate the formation-dissipation processes of MCSs and for modelers to improve their simulations of MCSs. As the first paper of a series, we briefly introduce the IHR MHROS and describe the specifications of its major instruments. Then, we provide an integrative analysis of the IHR MHROS observations for a heavy rain case on 3-5 July 2014 as well as the application of IHR MHROS observations in improving the model simulations. In a series of papers, we will tentatively answer several key scientific questions related to the MCS and Meiyu frontal systems over the middle region of the Yangtze River using the IHR MHROS observations.

  16. Risk Assessment on Dietary Exposure to Aflatoxin B1 in Post-Harvest Peanuts in the Yangtze River Ecological Region

    Directory of Open Access Journals (Sweden)

    Xiaoxia Ding

    2015-10-01

    Full Text Available Based on the 2983 peanut samples from 122 counties in six provinces of China’s Yangtze River ecological region collected between 2009–2014, along with the dietary consumption data in Chinese resident nutrition and health survey reports from 2002 and 2004, dietary aflatoxin exposure and percentiles in the corresponding statistics were calculated by non-parametric probability assessment, Monte Carlo simulation and bootstrap sampling methods. Average climatic conditions in the Yangtze River ecological region were calculated based on the data from 118 weather stations via the Thiessen polygon method. The survey results found that the aflatoxin contamination of peanuts was significantly high in 2013. The determination coefficient (R2 of multiple regression reflected by the aflatoxin B1 content with average precipitation and mean temperature in different periods showed that climatic conditions one month before harvest had the strongest impact on aflatoxin B1 contamination, and that Hunan and Jiangxi provinces were greatly influenced. The simulated mean aflatoxin B1 intake from peanuts at the mean peanut consumption level was 0.777–0.790 and 0.343–0.349 ng/(kg·d for children aged 2–6 and standard adults respectively. Moreover, the evaluated cancer risks were 0.024 and 0.011/(100,000 persons·year respectively, generally less than China’s current liver cancer incidence of 24.6 cases/(100,000 persons·year. In general, the dietary risk caused by peanut production and harvest was low. Further studies would focus on the impacts of peanut circulation and storage on aflatoxin B1 contamination risk assessment in order to protect peanut consumers’ safety and boost international trade.

  17. Risk Assessment on Dietary Exposure to Aflatoxin B₁ in Post-Harvest Peanuts in the Yangtze River Ecological Region.

    Science.gov (United States)

    Ding, Xiaoxia; Wu, Linxia; Li, Peiwu; Zhang, Zhaowei; Zhou, Haiyan; Bai, Yizhen; Chen, Xiaomei; Jiang, Jun

    2015-10-01

    Based on the 2983 peanut samples from 122 counties in six provinces of China's Yangtze River ecological region collected between 2009-2014, along with the dietary consumption data in Chinese resident nutrition and health survey reports from 2002 and 2004, dietary aflatoxin exposure and percentiles in the corresponding statistics were calculated by non-parametric probability assessment, Monte Carlo simulation and bootstrap sampling methods. Average climatic conditions in the Yangtze River ecological region were calculated based on the data from 118 weather stations via the Thiessen polygon method. The survey results found that the aflatoxin contamination of peanuts was significantly high in 2013. The determination coefficient (R²) of multiple regression reflected by the aflatoxin B₁ content with average precipitation and mean temperature in different periods showed that climatic conditions one month before harvest had the strongest impact on aflatoxin B₁ contamination, and that Hunan and Jiangxi provinces were greatly influenced. The simulated mean aflatoxin B₁ intake from peanuts at the mean peanut consumption level was 0.777-0.790 and 0.343-0.349 ng/(kg·d) for children aged 2-6 and standard adults respectively. Moreover, the evaluated cancer risks were 0.024 and 0.011/(100,000 persons·year) respectively, generally less than China's current liver cancer incidence of 24.6 cases/(100,000 persons·year). In general, the dietary risk caused by peanut production and harvest was low. Further studies would focus on the impacts of peanut circulation and storage on aflatoxin B₁ contamination risk assessment in order to protect peanut consumers' safety and boost international trade. PMID:26501322

  18. Long-term trend of haze pollution and impact of particulate matter in the Yangtze River Delta, China

    International Nuclear Information System (INIS)

    Haze pollution caused by heavy particulate matter (PM) loading brings significant damage in eastern China. Long-term monitoring from 1980 to 2011 and 1-year field measurement in 2011–2012 are used for investigating visibility variation and the impact of PM pollution for the Yangtze River Delta (YRD). It was found that visual range in the YRD endured a sharp reduction from 13.2 km to 10.5 km during 1980–2000. Average mass extinction efficiency (MEE) for inhalable PM (PM10) is 2.25 m2/g in 2001–2011, and extinction coefficient due to PM10 is 207 Mm−1, accounting for 36.2% of total extinction coefficient. MEE of PM2.5 and PM2.5–10 are 4.08 m2/g and 0.58 m2/g, respectively. Extinction coefficient due to PM2.5 and PM2.5–10 is 198 Mm−1 (39.6%) and 20 Mm−1 (4.0%) in 2011–2012. Maximum daily concentration of PM10 and PM2.5 is estimated to be 63 μg/m3 (RH: 73%) and 38 μg/m3 (RH: 70%) to keep visual range above 10 km. Fine particulate matter is the key factor for haze pollution improvement in the YRD area. -- Highlights: •Long-term visual range variation and its causes in the Yangtze River Delta are analyzed. •Quantitative contribution of particulate matter to haze pollution is estimated. •Mass extinction efficiency of PM10, PM2.5, and PM2.5–10 is estimated. -- The long-term variation of haze pollution in the YRD and its cause is investigated and the quantitative contribution of particulate matter to haze pollution is estimated

  19. The Effect of Urban Heat Island on Climate Warming in the Yangtze River Delta Urban Agglomeration in China

    Directory of Open Access Journals (Sweden)

    Qunfang Huang

    2015-07-01

    Full Text Available The Yangtze River Delta (YRD has experienced rapid urbanization and dramatic economic development since 1978 and the Yangtze River Delta urban agglomeration (YRDUA has been one of the three largest urban agglomerations in China. We present evidence of a significant urban heat island (UHI effect on climate warming based on an analysis of the impacts of the urbanization rate, urban population, and land use changes on the warming rate of the daily average, minimal (nighttime and maximal (daytime air temperature in the YRDUA using 41 meteorological stations observation data. The effect of the UHI on climate warming shows a large spatial variability. The average warming rates of average air temperature of huge cities, megalopolises, large cities, medium-sized cities, and small cities are 0.483, 0.314 ± 0.030, 0.282 ± 0.042, 0.225 ± 0.044 and 0.179 ± 0.046 °C/decade during the period of 1957–2013, respectively. The average warming rates of huge cities and megalopolises are significantly higher than those of medium-sized cities and small cities, indicating that the UHI has a significant effect on climate warming (t-test, p < 0.05. Significantly positive correlations are found between the urbanization rate, population, built-up area and warming rate of average air temperature (p < 0.001. The average warming rate of average air temperature attributable to urbanization is 0.124 ± 0.074 °C/decade in the YRDUA. Urbanization has a measurable effect on the observed climate warming in the YRD aggravating the global climate warming.

  20. Preliminary Study in Spatial Data Warehouse of Flood Control and Disaster Mitigation in Yangtze River Basin%长江防洪减灾空间数据仓库初步研究

    Institute of Scientific and Technical Information of China (English)

    詹小国

    2002-01-01

    Since 1990s,the spatial data warehouse technology has rapidly been developing, but due to the complexity of multi-dimensional analysis, extensive application of the spatial data warehouse technology is affected. In the light of the characteristics of the flood control and disaster mitigation in the Yangtze river basin, it is proposed to design a scheme about the subjects and data distribution of the spatial data warehouse of the flood control and disaster mitigation in Yangtze river basin, i.e., to adopt a distributed scheme. The creation and development of the spatial data warehouse of the flood control and disaster mitigation in Yangtze river basin is presented .The necessity and urgency of establishing the spatial data warehouse is expounded from the viewpoint of the present situation being short of available information for the flood control and disaster mitigation in Yangtze river basin.

  1. Indicators and impact analysis of sediment from the Changjiang Estuary and East China Sea to the Hangzhou Bay

    Institute of Scientific and Technical Information of China (English)

    WANG Hong; FAN Wei; YUN Caixing

    2004-01-01

    Based on the historical evolution of the Hangzhou Bay, by making use of the conclusions made by the previous research workers and the integration of concrete data, five distinct impact indicators of the sediment from the Changjiang Estuary and the East China Sea to the Hangzhou Bay are summarized. Numerical calculation and analysis indicate that the scouring and deposition of seabed in the Hangzhou Bay are subject to the direct impact of the evolution of the Changjiang Estuary, and the growth and decline and the direction of the sandy bar at Nanhuizui give traces to the sediment transport between the Changjiang Estuary and the Hangzhou Bay. The transport of sediment from the Changjiang Estuary to the Hangzhou Bay occurs mainly in winter and spring seasons and the increase of the Changjiang River runoff and the decrease of sediment charge have caused scouring in the northern coast of the Hangzhou Bay and the seabed erosion along the frontal margin of the Changjiang River Delta.

  2. Ancient Changjiang channel system in the East China Sea continental shelf during the last glaciation

    Institute of Scientific and Technical Information of China (English)

    LI Guangxue; LIU Yong; YANG Zigeng; YUE Shuhong; YANG Wenda; HAN Xibin

    2005-01-01

    Based on the data of high-resolution seismic profiles, an ancient river channel system of the last glaciation occurred along the Zhedong and Xihu depression in the southeast of Hupijiao rise. The distribution of the channel fill system shows that the ancient Changjiang River went through the Changjiang depression into the low land plain of the outside continental shelf during the low sea level cycle of the last glaciation. The big channel fill into Okinawa Trough is not found due to the depletion of the river kinetic energy in the low land plain. The river discharge dispersal was of an important role to the dilution of the northern Okinawa Trough sea at that time. Six ancient river channel systems (A―F), which are main distributaries of ancient Changjiang in the East China Sea continental shelf during the last glaciation, may be buried off the modern Changjiang estuary. The distribution of these channels coincides with the zonal elevations in the sea floor.

  3. Suspended sediment transport in the Deepwater Navigation Channel, Yangtze River Estuary, China, in the dry season 2009: 2. Numerical simulations

    Science.gov (United States)

    Song, Dehai; Wang, Xiao Hua

    2013-10-01

    A three-dimensional wave-current-sediment coupled numerical model with wetting and drying process is developed to understand hydrodynamics and sediment transport dynamics in the Deepwater Navigation Channel (DNC), the North Passage of the Yangtze River Estuary (YRE), China. The model results are in good agreement with observed data, and statistics show good model skill scores and correlation coefficients. The model well reproduces the spring-neap variation between a well-mixed estuary and a highly stratified estuary. Model results indicate that the estuarine gravitational circulation plays the most important role in the estuarine turbidity maximum (ETM) formation in the DNC. The upstream nonlocal sediment intrusion through the spillover mechanism is a major source of sediment trapping in the North Passage after the morphological changes. Numerical studies are conducted to show scenarios in the YRE under the effects of different forcings (river discharges, waves, and winds). Between these study cases, surface-wave-breaking relieves the sediment trapping and bottom-wave-current-interaction aggravates the bed erosion and elevates the SSC in the ETM; the former and the latter have the least and largest influence on the suspended sediment transport in the DNC. The wind effects have a greater influence on sediment trapping than the river discharges, and the steady northwesterly wind condition favors the siltation in the DNC most. The significance of density-driven turbidity current is also assessed, which can enhance the saline-water intrusion and suppress the turbulent mixing in the bottom boundary layer.

  4. 粉房湾长江大桥节段模型风洞试验%Wind Tunnel Test for Sectional Models of Fenfangwan Changjiang River Bridge

    Institute of Scientific and Technical Information of China (English)

    王骑; 廖海黎

    2012-01-01

    Fenfangwan Changjiang River Bridge is a semi-floating system cable-stayed bridge with double pylons and double cable planes. To verify the flutter stability of the bridge under the strong wind and the vortex-induced vibration performance under the common wind speed, the dynamic performance of the bridge was calculated and 6 models of the typical sections of the main girder were prepared according to the geometric scale ratio of 1 : 45. 8 for the wind tunnel fest. In the light of the test, the vibration control measure of installing guide vanes on the wind fairing edge trusses of the main girder was proposed. The results of the calculation and test indicate that the structural stiffness of the bridge is great, the vibration frequency is high* the flutter instability and static wind instability will not occur within the range of the test wind speed and the bridge can meet the requirements of the wind resistance design. By way of installing the guide vanes on the wind fairing edge trusses, the vortex-induced resonance of the bridge can be effectively controlled and the resonance can be made to meet the relevant requirements in the codes.%粉房湾长江大桥为双塔双索面半飘浮体系斜拉桥,为检验该桥在强风下的颤振稳定性及在常遇风速下的涡激振动性能,对该桥动力特性进行计算并按照1∶45.8的几何缩尺比制作6个标准主梁节段模型进行风洞试验,针对试验结果提出在主梁风嘴边桁处设置导流板的制振措施.计算和试验结果表明,该桥结构刚度大、振动频率高,在检验风速范围内不会发生颤振失稳和静风失稳,满足抗风设计要求;通过在主梁风嘴边桁处设置导流板,能够实现对桥梁涡激共振的有效控制,使其满足规范要求.

  5. A Novel Drinking Water Coagulant for Coagulating Changjiang River Water%一种处理长江水的新型自来水絮凝剂

    Institute of Scientific and Technical Information of China (English)

    曾德芳; 秦雯; 张水生; 丁复军

    2011-01-01

    In order to reduce the turbidity and aluminum ion of Changjiang river, a novel coagulant has been presented in this paper, which is called PCMS. And the proportion of this coagulant is V(0.1wt% PAFC):V(0.001wt% CTS): V (3wt% MS) = 25:5:7. Operational conditions of neutral pH and room temperature allow up to 98% turbidity and 67.3% aluminum ion removal with 5 mg-L-1 of coagulant. Stirring intensity and mixing periods, temperature and pH are evaluated and they are found to be less influential than coagulant dosage. Compared with the single classical coagulant, PCMS is more efficient than PAC, PFS and aluminum sulphate and so on.%为降低饮用水中铝离子含量并提高浊度去除率,研制了一种新型自来水絮凝剂(简称PCMS).该絮凝剂以聚合氯化铝铁(PAFC)、壳聚糖(CTS)和改性淀粉(MS)为主要组分,其配比为V(0.1wt%PAFC)∶V(0.001wt%CTS)∶V(3wt%MS)=25∶5∶7.在室温、中性条件下、絮凝剂投加量达到5 mg.L-1时,原水的浊度去除率可达98%以上,铝离子去除率可达67.3%.考察了絮凝剂投加量、搅拌时间、速度、温度、酸碱度等因素对其絮凝效果的影响.结果表明,絮凝剂的投加量对絮凝效果影响最大,其他因素则影响较小.相对于传统单一的絮凝剂如聚合氯化铝(PAC)、聚合硫酸铁(PFS)、硫酸铝等,PCMS投加量更小,处理效果更好,性价比更高.

  6. First identification of a possible nursery area for diadromous Coilia nasus in the Poyang Lake nearly 1000 km away from the Yangtze River Estuary

    Directory of Open Access Journals (Sweden)

    Jian Yang

    2015-11-01

    Full Text Available Estuarine tapertail anchovy Coilia nasus is a small-sized anadromous species in the Yangtze River, China. It is probably the most expensive fish in the world with price as high as $1000/kg and even $9600 for a single extremely large individual with a total length of 45.3 cm and body weight of 0.325 kg in the Jiangsu section of the river in 2012. However, when and where C. nasus spawn along the Yangtze River has still remained a mystery so far. In our field surveys of 2014 and 2015, some highly mature female and male C. nasus with stage V or VI gonads were firstly collected in the water region around Xingzi County in the Poyang Lake, which is nearly 1000 km away from the mouth of the Yangtze River. Although previous studies believed that all C. nasus in the Poyang Lake were freshwater residents, the otolith microchemistry signatures of the present study determined with EPMA and LA-ICPMS further clearly demonstrated that these fish were anadromous individuals. The findings indicated that the C. nasus migrated over nearly 1000 km upstream, with an extremely strong migration ability, passing through the lower reaches of the Yangtze River from the adjacent Yellow sea (even from the areas nearly straight line for as far as ca. 300 km off the Chinese coast line or East China Sea (Figure 1. The aforementioned evidence strongly suggests that the water region around Xingzi County in the Poyang Lake is a possible spawning/nursery area for anadromous C. nasus. It will be critical to ensure the protection of this region of the Poyang Lake being free from the environmental destruction of anthropogenic activities, especially hydraulic structure (especially dam construction and sand mining.

  7. Water Environment Protection in Yangzhou Section of Yangtze River%长江扬州段水环境保护研究

    Institute of Scientific and Technical Information of China (English)

    华迎春; 陈勤; 任晓梅; 高荣

    2001-01-01

    It is an urgent task at present to utilize resources of Yangtze River scientifically and reasonably and implement continuous development in the economic region along the river.This paper makes a special research on the status and evolution trend of water environment in Yangzhou section of the Yangtze River and puts forward a measure concerned to bring it under control by total amount control,especially make a breakthrough on pollution analysis and control countermeasure for non-point source based on a vast amount of monitoring data and basic material collected.The evaluation and forecast methods,determination of patternin flow & water quality and design condition,calculation on pollution effect in key section and mixed area of blowoff port etc.used in this paper have higher learning and practical value.It is significant for the protection of water environment and ecological environment,and provides basis for the research on water environment protection of Yangtze River and inspiration for water quality protection.This technology has good value in application and dissemination.

  8. Method and Practice on Water Function Division of the Yangtze River Region%长江片水功能区划分方法与实践

    Institute of Scientific and Technical Information of China (English)

    袁弘任; 罗小勇

    2002-01-01

    Water function classification is to divide the waters in a basin or a region into different water function regions according to the natural features such as water resources condition, physical geographical location, environmental condition, etc. and social features such as the status quo of development and utilization, the requirement of social and economic development on water quantity and quality etc. Water function division has not ever been carried out in China and no ready-made theory and method can be complied with, in the meantime, it is a fundamental work with strong practical function. Therefore, the basic concept and theory foundation and research method are put forward on the base of summary of water resources management and developed and will be perfected in practice process of water function division. The Yangtze function zone covers the Yangtze river basin, the Lancang river basin and the rivers in the western area of the Lancang river in Southwest China. According to the technical outline of national water function division and combined with division practice of the Yangtze function zone, this paper presents the scope determination, procedure and method of water function division.

  9. Spatial and temporal variations and controlling factors of sediment accumulation in the Yangtze River estuary and its adjacent sea area in the Holocene, especially in the Early Holocene

    Science.gov (United States)

    Feng, Zhibing; Liu, Baohua; Zhao, Yuexia; Li, Xishuang; Jiang, Li; Si, Shaokun

    2016-08-01

    The sub-bottom and collected borehole data provide insight into the transport and accumulation processes of the Yangtze-derived sediment in the study area since ~11 kyr BP. Five seismic units were identified according to six major acoustic surfaces. The sedimentary strata consist of fluvial, estuarine and deltaic systems from the bottom up, characterized by two different trends in sediment accumulation rates, i.e., low-high-low, and high-low-high. On the inner shelf of the East China Sea, the terrain with trough and ridge was formed by the Early Holocene transgression strata (formed in ~10 to 12 kyr BP) scoured by the later rectilinear tidal current due to postglacial sea-level transgression, and the sharply protruding seismic units are interpreted to be bedrocks outcropping on the seafloor. An analysis of the sedimentary characteristics in the boreholes and such factors as difference in accumulation rates, and tectonic subsidence led us to conclude that the paleo-coastline was located not far away from and to the east of Core ZK09 at ~9 kyr BP, and the southern bank of the Yangtze River estuary was located to the south of Core ZK09. At ~9 kyr, large volume of sediments was deposited in the northern isles of the Zhoushan archipelago and their adjacent bedrocks, forming a barrier effect on later sediment transport. During 7.5-8 kyr BP, the Yangtze-derived sediments were transported eastwards along the southern bank of the Yangtze River and the barrier due to the influence of the paleo-coastal current from the north, the direction of the Yangtze-derived sediment transport was split on the northeast of the Zhoushan archipelago, and the sediments covered the terrain with trough and ridge. During the high sea level period (7 kyr BP-present), the eastward migration of paleo-coastline had resulted in the increase in accumulation rate. We also conclude that the sharp increase in accumulation rate near the Yangtze River estuary after ~2 kyr BP was not primarily caused by

  10. Polychlorinated dibenzo-p-dioxins, dibenzofurans, and dioxin-like polychlorinated biphenyls in sediments from the Yellow and Yangtze Rivers, China.

    Science.gov (United States)

    Gao, Lirong; Huang, Huiting; Liu, Lidan; Li, Cheng; Zhou, Xin; Xia, Dan

    2015-12-01

    Polychlorinated dibenzodioxins and dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) are toxic environmental pollutants that are often found in sediments. The Yangtze and Yellow rivers in China are two of the largest rivers in Asia and are therefore important aquatic ecosystems; however, few studies have investigated the PCDD/F and PCB content in the sediments of these rivers. Accordingly, this study was conducted to generate baseline data for future environmental risk assessments. In the present study, 26 surface sediments from the middle reaches of the Yellow and Yangtze rivers were analyzed for PCDD/Fs and dioxin-like (dl) PCBs by high-resolution gas chromatography and high-resolution mass spectrometry. The ranges of PCDD/F, dl-PCB, and WHO-TEQ content in sediments from the Yellow River were 2.1-19.8, 1.11-9.9, and 0.08-0.57 pg/g (dry weight), respectively. The ranges of PCDD/F, dl-PCB, and WHO-TEQ content in sediments from the Yangtze River were 6.1-84.9, 1.8-24.1, and 0.13-0.29 pg/g (dry weight), respectively. Total organic carbon and dl-PCB contents in the Yellow River were significantly correlated (Spearman's correlation coefficient, r = 0.64, P PCB. Principal component analysis indicated that PCDD/Fs may arise from pentachlorophenol, sodium pentachlorophenate, and atmospheric deposition, while dl-PCBs likely originate from burning of coal and wood for domestic heating. The dioxin levels in the river sediments examined in this study were relatively low. These findings advance our knowledge regarding eco-toxicity and provide useful information regarding contamination sources. PMID:26282439

  11. 下荆江人工裁弯30年%River Cutoff Practices on Lower Jingjiang Section of Changjiang River in the Last 30 Years

    Institute of Scientific and Technical Information of China (English)

    潘庆燊

    2002-01-01

    River cutoff works have been implemented on Lower Jingjiang section for 30 years. Engineering practices have shown that channel straightening has been the river regulation measure for the permanent control of the meandering Lower Jingjiang section. River cutoff have been carried out in accordance with the evolution property of meandering rivers and these works have brought about expected benefits. It has also been noted that certain aspects in river cutoff had not been fully understood. River cutoff is a dynamic engineering. River channel evolution properties shall be fully understood so as to adroitly guide actions according to circumstances in cutoff works. In addition, river channel evolution observation and engineering effectiveness monitoring should be strengthened with a view to update the designs. The diversion canals for channel shortening are of great importance that will account for the success or failure of river cutoff works. The newly formed river channels and the river regime control works on the adjacent upper and lower reaches are guarantees for river cutoff works to be brought into play in the long run.

  12. Intensity distribution and effect of the Nov. 9, 1996 earthquake of MS=6.1 in offshore outside the Yangtze River Mouth on the South Korea

    Institute of Scientific and Technical Information of China (English)

    李裕澈; 李德基; 吴锡薰; 尹龙勋

    2003-01-01

    @@ On Nov. 9, 1996 at 21h56min (Beijing Time), an earthquake of MS=6.1 occurred in offshore outside the Yangtze River Mouth (31o43¢N, 123o04¢E). The shock affected Shanghai City and both Jiangsu and Zhejiang Provinces in China mainly. The shock was felt more strongly in the Yangtze River Mouth and Hangzhou Bay area than in the rest of them, particularly in high buildings of Shanghai City. In addition, the earthquake was felt in South Korea and also stronger in apartments or high buildings. LIU, JIN (1998) and LIU, et al (1999) described effect of the shock on the eastern China. The paper describes the effect of the earthquake on South Korea and the whole intensity distribution in South Korea and eastern China.

  13. Impacts of forest changes on hydrology: a case study of large watersheds in the upper reach of Yangtze River Basin

    Directory of Open Access Journals (Sweden)

    X. Cui

    2012-05-01

    Full Text Available Quantifying the effects of forest changes on hydrology in large watersheds is important for designing forest or land management and adaptation strategies for watershed ecosystem sustainability. Minjiang River watershed located in the upper reach of the Yangtze River Basin plays a strategic role in environmental protection and economic and social wellbeing for both the watershed and the entire Yangtze Basin. The watershed lies in the transition zone from Sichuan Basin to Qinghai-Tibet Plateau with a size of 24 000 km2. Due to its strategic significance, severe historic deforestation and high sensitivity to climate change, the watershed has long been one of the highest priority watersheds in China for scientific research and resource management. The purpose of this review paper is to provide a state-of-the-art summary on what we have learned from several recently-completed research programs (one of them known as "973 of the China National Major Fundamental Science" with funding of $3.5 million USD in 2002 to 2008. This summary paper focused on how land cover or forest change affected hydrology at both forest stand and watershed scales in this large watershed. Inclusion of two different spatial scales is useful because the results from a small spatial scale (e.g. forest stand level can help interpret the findings at a large spatial scale. Our review suggests that historic forest harvesting or land cover change has caused significant water increase due to reduction of forest canopy interception and evapotranspiration caused by removal of forest vegetation at both spatial scales. The impact magnitudes caused by forest harvesting indicate that the hydrological effects of forest or land cover changes can be as important as those caused by climate change, while the opposite impact directions suggest their offsetting effects on water yields in the Minjiang River watershed. In addition, different types of forests have different magnitudes of ET

  14. Impacts of forest changes on hydrology: a case study of large watersheds in the upper reach of Yangtze River Basin

    Science.gov (United States)

    Cui, X.; Liu, S.; Wei, X.

    2012-05-01

    Quantifying the effects of forest changes on hydrology in large watersheds is important for designing forest or land management and adaptation strategies for watershed ecosystem sustainability. Minjiang River watershed located in the upper reach of the Yangtze River Basin plays a strategic role in environmental protection and economic and social wellbeing for both the watershed and the entire Yangtze Basin. The watershed lies in the transition zone from Sichuan Basin to Qinghai-Tibet Plateau with a size of 24 000 km2. Due to its strategic significance, severe historic deforestation and high sensitivity to climate change, the watershed has long been one of the highest priority watersheds in China for scientific research and resource management. The purpose of this review paper is to provide a state-of-the-art summary on what we have learned from several recently-completed research programs (one of them known as "973 of the China National Major Fundamental Science" with funding of 3.5 million USD in 2002 to 2008). This summary paper focused on how land cover or forest change affected hydrology at both forest stand and watershed scales in this large watershed. Inclusion of two different spatial scales is useful because the results from a small spatial scale (e.g. forest stand level) can help interpret the findings at a large spatial scale. Our review suggests that historic forest harvesting or land cover change has caused significant water increase due to reduction of forest canopy interception and evapotranspiration caused by removal of forest vegetation at both spatial scales. The impact magnitudes caused by forest harvesting indicate that the hydrological effects of forest or land cover changes can be as important as those caused by climate change, while the opposite impact directions suggest their offsetting effects on water yields in the Minjiang River watershed. In addition, different types of forests have different magnitudes of ET with old-growth natural

  15. Element geochemistry of Holocene sediment and paleoenvironmental change in the Changjiang Estuary

    Institute of Scientific and Technical Information of China (English)

    杨守业; 李从先; 赵泉鸿

    2001-01-01

    Analyses of 41 elements reveal that Holocene sediments In the Changjiang Estuary bear regular elemental compositions in different sedimentary environments, and Holocene sediments came mainly from the Changjiang River based on compositions of REEs and most trace elements. Some heavy metals are more enriched in the surface sediment than in the deltaic sediments, reflecting human impact. Elemental compositions of the river channel sediment are related to the influence of proximal sediments. Sedimentary environments exert some influences on elemental compositions. Some chemical indices can be used to record chemical weathering undergone by the Changjiang sediment and environmental change.

  16. Assessment and exploitation of the waterfront resources in the middle and lower reaches of the Yangtze River%长江中下游岸线资源的特征及其评价利用

    Institute of Scientific and Technical Information of China (English)

    王传胜; 李建海; 朱丽东

    2003-01-01

    Waterfront resources are important and special kind of natural resources in the marginalarea between land and water. The Yangtze River, the longest river in China, is not only rich inwaterfront resources, but also has favorable development conditions with great potentiality. Aided bylarge-scale underwater topographic map, the major factors of the waterfront resources in the middleand lower reaches of the Yangtze River, such as the stability, the water depth and the naturalconditions for port construction, are assessed in this paper respectively on the basis of the overallinvestigations. The results show that: (1) the waterfront resources are abundant in the middle andlower reaches of the Yangtze River, but lack of perfectly combined high grade waterfront; (2) thereexists an obvious regional difference in the natural quality of the waterfront along the Yangtze; (3)the fore-bank water depth and waterfront stability are the main natural factors related to thewaterfront quality in the middle and lower reaches of the Yangtze River; (4) the waterfronts alongthe Yangtze are mainly used for port, warehouse and industrial purposes; and (5) the waterfronts nearimportant cities are highly used, especially the high-quality waterfronts. In addition, some suggestionsfor the development and utilization of the waterfront resources are presented in this paper.

  17. Modeling of the anthropogenic heat flux and its effect on regional meteorology and air quality over the Yangtze River Delta region, China

    OpenAIRE

    Xie, Min; Liao, Jingbiao; Wang, Tijian; Zhu, Kuanguang; Zhuang, Bingliang; Han, Yong; Li, Mengmeng; Li, Shu

    2016-01-01

    Anthropogenic heat (AH) emissions from human activities caused by urbanization can affect the city environment. Based on the energy consumption and the gridded demographic data, the spatial distribution of AH emission over the Yangtze River Delta (YRD) region is estimated. Meanwhile, a new method for the AH parameterization is developed in the WRF/Chem model, which incorporates the gridded AH emission data with the seasonal and diurnal variations into the simulations. By run...

  18. Farmers’ Sustainable Strategies for Soil Conservation on Sloping Arable Lands in the Upper Yangtze River Basin, China

    OpenAIRE

    Qiang Tang; Chansheng He; Xiubin He; Yuhai Bao; Ronghua Zhong; Anbang Wen

    2014-01-01

    The Upper Yangtze River Basin comprises a densely-populated agricultural region with mountainous and hilly landforms. Intensive cultivation has been extended onto steep hillslopes, which constitute the principal source area for sediment production. Soil conservation on sloping arable lands is thus of utmost priority for persisting sustainable agricultural production and maintaining sound ecosystem services. Although there have been many soil conservation techniques, either promoted by the gov...

  19. Examining the major contributors and controlling factors of ozone production in a rural area of the Yangtze River Delta region during harvest season

    OpenAIRE

    Pan, X; Kanaya, Y.; H. Tanimoto; S. Inomata; Wang, Z; Kudo, S.; Uno, I

    2014-01-01

    Open biomass burning (OBB) has been reported to emit substantial amounts of non-methane hydrocarbons (NMHCs), and the mixing of OBB with urban plumes could exacerbate regional ozone (O3) pollution. In the present study, an observational field campaign was performed in a rural area at the edge of Yangtze River Delta region (YRDR) during harvest season when intensive open burning of wheat residues was observed. The O3 production rate at the site was calculated using a p...

  20. Process analysis of regional ozone formation over the Yangtze River Delta, China using the Community Multi-scale Air Quality modeling system

    OpenAIRE

    Li, L.; Chen, C H; Huang, C.; H. Y. Huang; Zhang, G. F.; Wang, Y. J.; Wang, H L; S. R. Lou; L. P. Qiao; Zhou, M.; Chen, M. H.; Chen, Y. R.; Streets, D.G.; J. S. Fu; C. J. Jang

    2012-01-01

    A high O3 episode was detected in urban Shanghai, a typical city in the Yangtze River Delta (YRD) region in August 2010. The CMAQ integrated process rate method is applied to account for the contribution of different atmospheric processes during the high pollution episode. The analysis shows that the maximum concentration of ozone occurs due to transport phenomena, including vertical diffusion and horizontal advective transport. Gas-phase chemistry producing O3 mainly occurs...

  1. Process analysis of regional ozone formation over the Yangtze River Delta, China using the Community Multi-scale Air Quality modeling system

    OpenAIRE

    Li, L.; Chen, C. H.; Huang, C; Huang, H Y; Zhang, G. F.; Wang, Y. J.; Wang, H. L.; Lou, S. R.; Qiao, L. P.; Zhou, M.; Chen, M H; Chen, Y. R.; D. G. Streets; Fu, J.S.; C. J. Jang

    2012-01-01

    A high O3 episode was detected in urban Shanghai, a typical city in the Yangtze River Delta (YRD) region in August 2010. The CMAQ integrated process rate method is applied to account for the contribution of different atmospheric processes during the high pollution episode. The analysis shows that the maximum concentration of ozone occurs due to transport phenomena, including vertical diffusion and horizontal advective transport. Gas-phase chemistry producing O

  2. Elevational pattern of species richness in the Three Gorges region of the Yangtze River: effect of climate, geometric constraints, area and topographical heterogeneity

    OpenAIRE

    Qiaoyan Li; Xiangping Wang

    2013-01-01

    In this paper, we explore altitudinal richness of vascular plant species in the Three Gorges region of the Yangtze River and test several hypotheses concerning geographic diversity patterns. Multivariate regression and variation partitioning analyses were used to examine the relative effects of area, climate, geometric constraints and topographical heterogeneity on altitudinal richness patterns, and also the differences among ecological groups (including species with different range sizes, gr...

  3. Advantages of city-scale emission inventory for urban air quality research and policy: the case of Nanjing, a typical industrial city in the Yangtze River Delta, China

    OpenAIRE

    Zhao, Y.; Qiu, L; Xu, R.; Xie, F; Q. Zhang; Yu, Y.; C. P. Nielsen; Qin, H.; Wang, H.; Wu, X; Li, W; J. Zhang

    2015-01-01

    With most eastern Chinese cities facing major air quality challenges, there is a strong need for city-scale emission inventories for use in both chemical transport modeling and the development of pollution control policies. In this paper, a high-resolution emission inventory of air pollutants and CO2 for Nanjing, a typical large city in the Yangtze River Delta, is developed incorporating the best available information on local sources. Emission factors and ...

  4. TIE SOIL DEGRADATION AND FERTILITY RECONSTRUCTION IN REGION OF CHANGNING CULTIVATION INTO TREE PLANTING IN CHANGJIANG RIVER RIVER UPSTREAM%长江上游退耕还林区的土壤退化与肥力重建

    Institute of Scientific and Technical Information of China (English)

    何毓蓉; 张丹; 宫阿都

    2000-01-01

    长江上游退耕还林战略举措的关键技术之一是要模清该区土壤性状和退化问题,进而采取行之有效的土壤退化防治措施。尽快恢复生态,保护长江安全。以占该区面积最大的紫色土退化为例,提出了该区土壤退化特征、类型和发生现状。指出该区环境的脆弱性和人为干扰是土壤退化根本成因。建议:(1)建立保护区全面封禁管护(2)构建网格生物篱保持水土增厚土层(3)加强土壤碳氮物质循环强化培肥(4)分带治土造林建立垄沟种植培肥体系等,以达到土壤肥力重建,取得退耕还林成效。%The one of key methods for success in operating the strategy of changing cultivation into tree planting in Changjiang River upstream is as follows. The first is the problem of soil nature and degradation in this region should be understood. Then the available way for preventing soil from degradation will be given out. The ecologic balance should be recovered as soon as possible and the safety of Changjiang should be protected. For example of degradation of purple soil which accounts for the largest area in this region, this paper mentions the characteristics, type and development of soil degradation in this region. The foundamental reason of soil degradation developoment is environmental weakness and human disturbance. On the base of reason above the following methods were put forward: (1) building closed protection and management belt in protection site. (2) constructing network-like biological fence for water soil conservation and soil thickening. (3) strongthening soil material cycle with C/N for fertilization. (4) soil management, afforestation in belt and soil fertilizing system in furrow should be established for reconstructing soil fertility and results of changing cultivation into tree planting.

  5. The profile of antibiotics resistance and integrons of extended-spectrum beta-lactamase producing thermotolerant coliforms isolated from the Yangtze River basin in Chongqing

    International Nuclear Information System (INIS)

    The spreading of extended-spectrum β-lactamases (ESBL)-producing thermotolerant coliforms (TC) in the water environment is a threat to human health but little is known about ESBL-producing TCs in the Yangtze River. We received 319 ESBL-producing stains obtained from the Chongqing basin and we investigated antibiotic susceptibility, bla gene types and the presence of integrons and gene cassettes. 16.8% of TC isolates were ESBL-producing bacteria and blaTEM+CTx-M was the predominant ESBL type. 65.2% of isolates contained class 1 integrons, but only 3 carried intI 2. Gene cassettes were amplified and sequenced. aadA, drfA, cmlA, sat1, aar3 and two ORF cassettes were found. In conclusion, Yangtze River is heavily polluted by ESBL-producing TC bacteria and the combined bla gene type could enhance antibiotic resistance. Class 1 integrons were widespread in ESBL-producing isolates and play an important role in multi-drug resistance. Characterization of gene cassettes could reveal the dissemination of antibiotic resistance genes. - Yangtze River is heavily polluted by ESBL-producing TC bacteria and Class 1 integrons play an important role in multi-drug resistance.

  6. Passive air sampling of organochlorine pesticides and polychlorinated biphenyls in the Yangtze River Delta, China: Concentrations, distributions, and cancer risk assessment

    International Nuclear Information System (INIS)

    The Yangtze River Delta (YRD) has been quickly industrialized and urbanized. Passive air sampling of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) was carried out in the YRD in 2010–2011 to investigate their spatiotemporal distributions and estimate the risk of cancer from their inhalation. Annual concentrations were 151, 168, 18.8, 110, 17.9, and 35.0 pg m−3 for HCB, ∑DDTs, ∑HCHs, ∑chlordane, mirex, and PCBs, respectively. The highest OCP and PCB concentrations were generally detected in the autumn and winter. The average concentrations of OCPs and PCBs for the different site groups followed the order urban ≈ urban–rural transition > rural. The lifetime excess cancer risks from the inhalation of OCPs and PCBs were −6. The predicted cancer cases per lifetime associated with the inhalation of OCPs and PCBs are 12, 7, and 4 per ten thousand people for urban, urban–rural transition, and rural areas, respectively. Highlights: •Organochlorine pollutants were measured in the air in the Yangtze River Delta area. •Air PCB concentration declined in recent years comparing with previous results. •HCB and DDEs predominated, with the highest values in winter and autumn, respectively. •OCPs and PCBs followed the order: urban ≈ urban–rural transition > rural. -- A detailed study of organochlorine pesticides and polychlorinated biphenyls in air across the Yangtze River Delta area using passive air samplers

  7. Reproductive toxicity assessment of surface water of the Tai section of the Yangtze River, China by in vitro bioassays coupled with chemical analysis

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xiaoyi [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Jiangsu Academy of Environmental Science, Nanjing 210036 (China); Wu Jiang [Laboratory of Immunology and Reproductive Biology, School of Medicine, Nanjing University, Nanjing 210093 (China); Hao Yingqun [Environmental Monitoring Center of Jiangsu Province, Nanjing 210036 (China); Zhu Bingqing [State Key Laboratory in Marine Pollution, Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong (Hong Kong); Shi Wei [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Hu Guanjiu [Environmental Monitoring Center of Jiangsu Province, Nanjing 210036 (China); Han Xiaodong [Laboratory of Immunology and Reproductive Biology, School of Medicine, Nanjing University, Nanjing 210093 (China); Giesy, John P. [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); State Key Laboratory in Marine Pollution, Department of Biology and Chemistry, City University of Hong Kong, Kowloon, Hong Kong (Hong Kong); Department of Veterinary Biomedical Sciences and Toxicology Centre, University of Saskatchewan (Canada); Zoology Department, College of Science, King Saud University, Riyadh (Saudi Arabia); Yu Hongxia, E-mail: yuhx@nju.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China)

    2011-10-15

    Reproductive toxicity of organic extracts of the surface water from the Tai section of the Yangtze River was assessed by in vitro cytotoxity assays and selected persistent organic pollutants including PCBs, OCPs and PAHs were quantified by instrumental analysis. Eleven of the US EPA priority PAHs were detected. Individual PAHs were found to range from 0.7 to 20 ng/L. Concentrations of BaP did not exceed the national drinking water source quality standard of China. However, a 286-fold concentrated organic extract induced significant reproductive toxicity in adult male rats. The morphology of cells, MTT assay and LDH release assay were all affected by exposure to the organic extracts of water. The results of the reproductive toxicity indicated that PAHs posed the greatest risk of the chemicals studied. The compounds present in the water could be bioconcentrated and result in adverse effects. - Highlights: > Only 11 PAHs of US EPA priority PAHs were detected in surface water the Yangtze River. > Level of BaP didn't exceed national drinking water source quality standard of China. > 286-fold concentrated organic extracts induced great reproductive toxicity in rats. > PAHs posed the greatest risk of the chemicals studied. > The compounds in the water could be bioconcentrated and result in adverse effects. - In vitro bioassay responses observed in Yangtze River source water extracts showed great reproductive toxicity, and PAHs were responsible.

  8. Land Use/Cover Dynamics in Response to Changes in Environmental and Socio-Political Forces in the Upper Reaches of Yangtze River, China

    Directory of Open Access Journals (Sweden)

    Zhenyao Shen

    2008-12-01

    Full Text Available Land use/cover change (LUCC, which results from the complex interaction of social, ecological and geophysical processes, is a major issue and the main cause of global environmental change. This study analyzed the land use/cover dynamics and their environmental and socio-political forces in the upper reaches of Yangtze River from 1980 to 2000 by using remote sensing, climatic and socio-economic data from both research institutes and government departments. The results indicated that there had been significant land use/cover changes between 1980 and 2000 in the study area, which were characterized by a severe replacement of cropland and woodland with grassland and built-up land. The transition matrices highlight the dominant dynamic events and the internal conversions between land use/cover types during the study period and reveal two distinct transition phases. Land use/cover changes in the upper reaches of Yangtze River during 1980 to 2000, while restricted by environmental attributes, were strongly driven by socio-political factors. However, excessively pursuing higher land use benefits likely results in serious environmental degradation. This study suggests that the restructuring of land use should be based on land suitability and sustainable protection of fragile environment in the upper reaches of Yangtze River. A thorough comprehension of historical changes will enhance our capability to predict future land use change and contribute to effective management strategies and policies for the rational land use.

  9. The profile of antibiotics resistance and integrons of extended-spectrum beta-lactamase producing thermotolerant coliforms isolated from the Yangtze River basin in Chongqing

    Energy Technology Data Exchange (ETDEWEB)

    Chen Hao [Department of Environmental Hygiene, School of Military Preventive Medicine, Third Military Medical University, 30 Gaotanyan Street, Chongqing 400038 (China); Shu Weiqun, E-mail: west2003@sohu.co [Department of Environmental Hygiene, School of Military Preventive Medicine, Third Military Medical University, 30 Gaotanyan Street, Chongqing 400038 (China); Chang Xiaosong; Chen Jian; Guo Yebin; Tan Yao [Department of Environmental Hygiene, School of Military Preventive Medicine, Third Military Medical University, 30 Gaotanyan Street, Chongqing 400038 (China)

    2010-07-15

    The spreading of extended-spectrum {beta}-lactamases (ESBL)-producing thermotolerant coliforms (TC) in the water environment is a threat to human health but little is known about ESBL-producing TCs in the Yangtze River. We received 319 ESBL-producing stains obtained from the Chongqing basin and we investigated antibiotic susceptibility, bla gene types and the presence of integrons and gene cassettes. 16.8% of TC isolates were ESBL-producing bacteria and bla{sub TEM+CTx-M} was the predominant ESBL type. 65.2% of isolates contained class 1 integrons, but only 3 carried intI 2. Gene cassettes were amplified and sequenced. aadA, drfA, cmlA, sat1, aar3 and two ORF cassettes were found. In conclusion, Yangtze River is heavily polluted by ESBL-producing TC bacteria and the combined bla gene type could enhance antibiotic resistance. Class 1 integrons were widespread in ESBL-producing isolates and play an important role in multi-drug resistance. Characterization of gene cassettes could reveal the dissemination of antibiotic resistance genes. - Yangtze River is heavily polluted by ESBL-producing TC bacteria and Class 1 integrons play an important role in multi-drug resistance.

  10. Features of the short-term position variation of the west Pacific subtropical high during the torrential rain in Yangtze-Huaihe river valley and its possible cause

    Science.gov (United States)

    Guan, Zhaoyong; Yu, Bo; Wang, Lijuan; He, Jielin; Zeng, Gang

    2009-08-01

    By using the NCEP/NCAR daily reanalysis data, CMAP precipitation data , daily precipitation data of 740 stations in China and some remote sensing data, features of the short-term position variation of the west Pacific subtropical high(WPSH) during the torrential rain in Yangtze-Huaihe river valley and its possible cause are analyzed. Results show that the short-term position variation of WPSH is closely associated with the diabatic heating. During the torrential rain period, the apparent heating source and apparent moisture sink are exceptionally strong over Yangtze-Huaihe river valley( on the northwest side of WPSH )and the Bay of Bengal (to the west of WPSH). Based on the complete form of vertical vorticity tendency equation, it is found that the heating field over Yangtze-Huaihe river valley during the torrential rain period, which is in favor of the increase of cyclonic vorticity on the north side of WPSH, is unfavorable to the WPSH moving northward. And the heat source over the Bay of Bengal ,which is in favor of the increase of anti-cyclonic vorticity on the west of WPSH, may induce the westward extension of WPSH.

  11. Reproductive toxicity assessment of surface water of the Tai section of the Yangtze River, China by in vitro bioassays coupled with chemical analysis

    International Nuclear Information System (INIS)

    Reproductive toxicity of organic extracts of the surface water from the Tai section of the Yangtze River was assessed by in vitro cytotoxity assays and selected persistent organic pollutants including PCBs, OCPs and PAHs were quantified by instrumental analysis. Eleven of the US EPA priority PAHs were detected. Individual PAHs were found to range from 0.7 to 20 ng/L. Concentrations of BaP did not exceed the national drinking water source quality standard of China. However, a 286-fold concentrated organic extract induced significant reproductive toxicity in adult male rats. The morphology of cells, MTT assay and LDH release assay were all affected by exposure to the organic extracts of water. The results of the reproductive toxicity indicated that PAHs posed the greatest risk of the chemicals studied. The compounds present in the water could be bioconcentrated and result in adverse effects. - Highlights: → Only 11 PAHs of US EPA priority PAHs were detected in surface water the Yangtze River. → Level of BaP didn't exceed national drinking water source quality standard of China. → 286-fold concentrated organic extracts induced great reproductive toxicity in rats. → PAHs posed the greatest risk of the chemicals studied. → The compounds in the water could be bioconcentrated and result in adverse effects. - In vitro bioassay responses observed in Yangtze River source water extracts showed great reproductive toxicity, and PAHs were responsible.

  12. An 800-year record of terrestrial organic matter from the East China Sea shelf break: Links to climate change and human activity in the Changjiang Basin

    Science.gov (United States)

    Li, Zhong Qiao; Wu, Ying; Liu, Su Mei; Du, Jin Zhou; Zhang, Jing

    2016-02-01

    The East China Sea (ECS) is a large river dominated marginal sea and receives massive volumes of terrestrial material from the Changjiang (Yangtze River). As the ECS preserves a record of terrestrial material derived from the Changjiang Basin, cores collected from this region can be used to reconstruct paleoclimate change and human disturbance in the watershed. A core (P4) was collected from the ECS shelf break and analyzed for bulk parameters (organic carbon (OC), total nitrogen (TN), and stable carbon isotopes (δ13C)), lignin phenols, and 3,5-dihydroxy benzoic acid (DHBA). The depth profiles of these parameters indicate stable and consistent marine production. The lignin source indices, cinnamyl phenols vs. vanillyl phenols (C/V) and syringyl phenols vs. vanillyl phenols (S/V), were in agreement with previously reported results from ECS surface sediments, but differed markedly from Bohai Sea surface sediments. The ratio of acid to aldehyde in vanillyl phenols ((Ad/Al)v) indicated the terrestrial OC in this core was refractory. At the same time, the variation in lignin phenols is positively correlated with the strength of the Indian Summer Monsoon (ISM) over the last 800 years (pdrought events, around 1580 A.D. and 1770 A.D. were also identified in the core based on the extremely low C/V, S/V, lignin phenol vegetation index (LPVI), and DHBA values. Furthermore, the significant shift in C/V and S/V since 1880 A.D. is probably a reflection of increased human activity in the upper Changjiang Basin over this period.

  13. Millennial-Scale Asian Monsoon Influenced Longjie Lake Evolution during Marine Isotope Stage 3, Upper Stream of Changjiang (Yangtze River, China

    Directory of Open Access Journals (Sweden)

    Chaozhu Li

    2015-01-01

    Full Text Available Millennial-scale climate change in Asian monsoon region during MIS 3 has been studied using stalagmite, loess, and peat sediments. However, records from more materials are essential to further illustrate dynamics of these events. In the present study, a time-series of grain size covering 60–30 ka was reconstructed from lake sediments in the Yunnan Province, southwestern China. The time-series contains 14 obvious millennial-scale events during the period. On millennial-scale, the grain size record is generally consistent with mean stalagmite δ18O from Hulu Cave, grain size of Gulang loess sequence, Chinese Loess Plateau, and Greenland ice core δ18O. The results show that the millennial-scale variation was well compared with the Dansgaard-Oeschger (DO events, indicating that those global events were well documented in lake sediments in the Asian monsoon region. Because the grain size can be used as a proxy for water discharge, we suggest that signal of the DO events might be transmitted to lake evolution by Asian monsoon.

  14. Influence of the characteristics of atmospheric boundary layer on the vertical distribution of air pollutant in China's Yangtze River Delta

    Science.gov (United States)

    Wang, Chenggang; Cao, Le

    2016-04-01

    Air pollution occurring in the atmospheric boundary layer is a kind of weather phenomenon which decreases the visibility of the atmosphere and results in poor air quality. Recently, the occurrence of the heavy air pollution events has become more frequent all over Asia, especially in Mid-Eastern China. In December 2015, the most severe air pollution in recorded history of China occurred in the regions of Yangtze River Delta and Beijing-Tianjin-Hebei. More than 10 days of severe air pollution (Air Quality Index, AQI>200) appeared in many large cities of China such as Beijing, Tianjin, Shijiazhuang and Baoding. Thus, the research and the management of the air pollution has attracted most attentions in China. In order to investigate the formation, development and dissipation of the air pollutions in China, a field campaign has been conducted between January 1, 2015 and January 28, 2015 in Yangtze River Delta of China, aiming at a intensive observation of the vertical structure of the air pollutants in the atmospheric boundary layer during the time period with heavy pollution. In this study, the observation data obtained in the field campaign mentioned above is analyzed. The characteristics of the atmospheric boundary layer and the vertical distribution of air pollutants in the city Dongshan located in the center of Lake Taihu are shown and discussed in great detail. It is indicated that the stability of the boundary layer is the strongest during the nighttime and the early morning of Dongshan. Meanwhile, the major air pollutants, PM2.5 and PM10 in the boundary layer, reach their maximum values, 177.1μg m-3 and 285μg m-3 respectively. The convective boundary layer height in the observations ranges from approximately 700m to 1100m. It is found that the major air pollutants tend to be confined in a relatively shallow boundary layer, which represents that the boundary layer height is the dominant factor for controlling the vertical distribution of the air pollutants. In

  15. Characteristics and sources of PM2.5-bound carbonaceous aerosols in the Yangtze River Delta, China

    Science.gov (United States)

    Hong, Youwei; Hong, Zhenyu; Chen, Jinsheng

    2016-04-01

    An investigation of atmospheric fine particle (PM2.5) from Shanghai, Nanjing and Ningbo in the Yangtze River Delta was conducted during Nov 2014 and Aug 2015. Organic species, including 16 polycyclic aromatic hydrocarbons (PAHs), 10 nitro-PAHs and C8 to C40 n-alkanes, and stable carbon isotopes OC (δ13COC) and EC (δ13CEC) were used to evaluate carbonaceous aerosols' spatiotemporal variations and identify their potential sources. The averaged concentrations of total PAHs and n-alkanes in Shanghai, Nanjing and Ningbo were 16.5 and 101.1 ng m-3, 21.1 and 128.2 ng m-3, 33.0 and 241.1 ng m-3, respectively, while the mean concentrations of 10 nitro-PAHs was 2.02, 2.37 and 2.70 ng m-3. Seasonal variations of organic compounds were listed in the following order: winter > autumn > spring > summer. N-alkanes detected in PM2.5 were characterized by odd carbon number preference, with a unimodal peak shape. The maximum carbon number (Cmax) was C29, followed by C27 and C31. According to diagnostic ratios and principle components analysis (PCA) methods, vehicle emissions and coal burning were the dominant sources of PAHs. The ratios of 2-nitrofluoranthene to 1-nitropyrene were larger than 5, indicating that atmospheric transformation from PAHs was a major source of nitro-PAHs. Meanwhile, primary emissions tracers i.e., 1-nitropyrene (the mean concentration of 0.024 ng m-3 in all cities) was observed, suggesting primary contribution of motor vehicle exhaust to the fine particulate organic aerosols. In addition, isotope abundances (δ13COC=‑24.6±0.8‰ and δ13CEC = ‑23.9±1.4‰) and EC/TC ratio (0.2 < EC/TC < 0.5) in Shanghai demonstrated that fossil fuels (e.g. motor vehicles) were the most important source for carbonaceous PM2.5. We further focus on radiocarbon (14C) analysis and gas/particle partitioning of organic tracers on different size particles. Keywords: organic tracers; stable carbon isotopes; spatiotemporal variations; sources apportionment; Yangtze River Delta

  16. Characteristics and sources of PM2.5-bound carbonaceous aerosols in the Yangtze River Delta, China

    Science.gov (United States)

    Hong, Youwei; Hong, Zhenyu; Chen, Jinsheng

    2016-04-01

    An investigation of atmospheric fine particle (PM2.5) from Shanghai, Nanjing and Ningbo in the Yangtze River Delta was conducted during Nov 2014 and Aug 2015. Organic species, including 16 polycyclic aromatic hydrocarbons (PAHs), 10 nitro-PAHs and C8 to C40 n-alkanes, and stable carbon isotopes OC (δ13COC) and EC (δ13CEC) were used to evaluate carbonaceous aerosols' spatiotemporal variations and identify their potential sources. The averaged concentrations of total PAHs and n-alkanes in Shanghai, Nanjing and Ningbo were 16.5 and 101.1 ng m-3, 21.1 and 128.2 ng m-3, 33.0 and 241.1 ng m-3, respectively, while the mean concentrations of 10 nitro-PAHs was 2.02, 2.37 and 2.70 ng m-3. Seasonal variations of organic compounds were listed in the following order: winter > autumn > spring > summer. N-alkanes detected in PM2.5 were characterized by odd carbon number preference, with a unimodal peak shape. The maximum carbon number (Cmax) was C29, followed by C27 and C31. According to diagnostic ratios and principle components analysis (PCA) methods, vehicle emissions and coal burning were the dominant sources of PAHs. The ratios of 2-nitrofluoranthene to 1-nitropyrene were larger than 5, indicating that atmospheric transformation from PAHs was a major source of nitro-PAHs. Meanwhile, primary emissions tracers i.e., 1-nitropyrene (the mean concentration of 0.024 ng m-3 in all cities) was observed, suggesting primary contribution of motor vehicle exhaust to the fine particulate organic aerosols. In addition, isotope abundances (δ13COC=‑24.6±0.8‰ and δ13CEC = ‑23.9±1.4‰) and EC/TC ratio (0.2 fossil fuels (e.g. motor vehicles) were the most important source for carbonaceous PM2.5. We further focus on radiocarbon (14C) analysis and gas/particle partitioning of organic tracers on different size particles. Keywords: organic tracers; stable carbon isotopes; spatiotemporal variations; sources apportionment; Yangtze River Delta

  17. Geometric properties of river cross sections and associated hydrodynamic implications in Wuhan-Jiujiang river reach, the Yangtze River%长江中游武汉-九江河段河道形态及水动力学特征

    Institute of Scientific and Technical Information of China (English)

    张强; 施雅风; 熊明

    2009-01-01

    Based on measured hydrological data by using ship-mounted Acoustic Doppler Current Profiler (ADCP) instrument, we analyzed shapes of river cross sections of the middle Yangtze River basin (mainly focusing on Makou and Tianjiazhen river reach). Hydrodynamic properties of river channels were also discussed. The research results indicate that nonlinear relationships can be identified between river-width/river-depth ratio (W/D ratio), sizes of cross section and mean flow velocity. Positive relations are detected between W/D ratio and mean flow velocity when W/D<1; and negative relations are observed when W/D>1. Adverse relationships can be obtained between W/D ratio and cross-section area. Geomorphologic and geologic survey indicates different components of river banks in the wider and narrower river reaches respectively. These may be the main driving factors causing unique hydrological properties of river channels in the middle Yangtze River basin. Narrower river cross sections tend to raise water level in the upstream river reach near narrower river channel, giving rise to backwater effects. River knots can cause serious backwater effects, which is harmful for flood mitigation. However river knots will also stabilize river channel and this will be beneficial for river channel management. The results of this paper may be helpful for flood mitigation and river channel management in the middle Yangtze River basin.

  18. STUDY OF RED TIDE PREDICTION MODEL FOR THE CHANGJIANG ESTUARY

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    This paper based on field data (on red tide water quality monitoring at the Changjiang River mouth and Hutoudu mariculture area in Zhejiang Province from May to August in 1995, and May to September in 1996) presents an effective model for short term prediction of red tide in the Changjiang Estuary. The measured parameters include: depth, temperature, color diaphaneity, density, DO, COD and nutrients (PO4-P, NO2-N, NO3-N, NH4-N). The model was checked by field-test data, and compared with other related models.The model: Z=SAL-3.95 DO-2.974 PH-5.421 PO4-P is suitable for application to the Shengsi aquiculture area near the Changjiang Estuary.

  19. 长江口放射性核素Pu的大气湿沉降初步研究%Atmospheric Wet Deposition of Radionuclide Pu in the Changjiang River Estuary Region

    Institute of Scientific and Technical Information of China (English)

    张克新; 潘少明; 徐仪红; 曹立国; 徐伟; 张威; 郝永佩

    2016-01-01

    Anthropogenic radionuclides (137Cs, 90Sr, and Pu isotopes) released from atmospheric nuclear tests, ma-jor nuclear reactor accidents, and other sources can be detected in the environment in most parts of the world. In particular, as a result of atmospheric nuclear explosions, about 15 PBq of 239,240Pu (1 PBq=1015 Bq) and 0.3 PBq of 238Pu have been globally released into the atmosphere. These radionuclides may be useful tracers of environ-mental changes, such as desertification, erosion and sedimentation processes, in terrestrial regions. Further-more, measurements of radionuclide deposition are useful for several purposes, including the assessment of the effects of radiation from anthropogenic radionuclides on humans. They may also find use as indicators of envi-ronmental events. Most of the current investigations focus on the chemical behaviors such as transfer and diffu-sion in environment, but for the atmospheric wet deposition of radionuclide Pu, the publically available report is very limited in China. In this article, we investigated and quantified preliminarily the 239,240Pu atmospheric de-position in the Changjiang River Estuary Region based on the records of 239,240Pu atmospheric deposition and pre-cipitation in Tokyo in Japan. The results indicated that 239,240Pu atmospheric deposition history in the Changjiang River Estuary Region was similar to that of the whole north hemisphere. The cumulative atmospheric deposi-tion inventory of 239,240Pu was estimated to be 34.556 Bq/m2 in 1957-2005. The maximum annual deposition oc-curred in 1963 after the large-scale atmospheric nuclear weapons testing in 1950s-1960s conducted by the Unit-ed States and former USSR. Annual 239,240Pu deposition decreased in the period from 1963 to 1967 according to the stratospheric residence time of nuclear debris. In the 1970s, the radionuclide deposition observed in the Changjiang River Estuary showed no decrease because of a series of American and Chinese atmospheric nucle

  20. Discharge Estimation of the Yangtze River's Paleovalley near the No.4 Nanjing Yangtze River Bridge in the Last Glacial Maximum%末次盛冰期南京长江四桥附近长江古流量估算

    Institute of Scientific and Technical Information of China (English)

    爨景波; 曹光杰

    2013-01-01

    利用南京长江四桥的39个地质工程钻孔资料及其它现有资料,已知长江四桥附近约-65~-90 m的深槽为末次盛冰期时的长江河槽.根据古河槽断面、形态参数、底部沉积物颗粒级配等,运用河相关系法、泥沙粒径水力学法、地貌水力学法,计算了末次盛冰期时的断面面积、断面平均流速.计算得到末次盛冰期南京长江四桥附近长江古流量约为22000~27000m3/s.初步根据宽深比、悬移质含量、弯曲率等参数值判断末次盛冰期长江四桥附近长江古河型为曲流.%Using 39 geological engineering drilling data and other available data for the No. 4 Nanjing Yangtze River Bridge, we can see that the paleovalley is dated to LGM at a depth of -60~-90 m near the No. 4 Nanjing Yangtze River Bridge. According to the paleovalley section, shape parameters, particle size grading of sediments in the incised-valley and so on, the cross section area and average velocity of the LGM were calculated by such ways as the hydraulic geometry method, the sediment particle size-hydraulics method and the geomorphology-hydraulics method. At the end, the discharge in the No. 4 Nanjing Yangtze River Bridge near the Yangtze River during the LGM has been estimated to be around 22 000~27 000 m3/s. Moreover, the ancient Yangtze River near the No. 4 Nanjing Yangtze River Bridge in the LGM was a meander river according to the width-depth ratio, suspended sediment concentrations, and channel curvature.

  1. Flux of 238U and 232Th in Changjiang estuary

    International Nuclear Information System (INIS)

    The study of fluxes of the U, Th of Changjiang River into the East China Sea and its adjacent waters is basic work to understanding of U, Th tracer theirselves and their corresponding biogeochemical cycles process in estuaries, coastal. By sampling in the Xuliujing (i.e. the interface between fresh water and sea water) every month, 200 L water was filtered through 0.45μm fabric cartridge to collect particle nuclides. The dissolved nuclides were co-precipitated using Fe(OH)3 and MnO2. The range of 238U activity in water is 2.30-10.32 Bq·m-3, with an average of 5.48±1.19 Bq·m-3; the activity of 232Th is 1.08-2.32 Bq·m-3, with an average of 1.75±0.29 Bq·m-3. Changjiang River conveyed 238U 4.06 x 1012Bq, 232Th 1.54 x 1012 Bq into the estuary every year. Further study of the seasonal variations 238U, 232Th input to the sea, indicating that: the activity of 238U and Changjiang River estuary water flux have a certain degree of negative correlation (R2=0.65, n=12); the main source of 232Th is the weathering of the river. The activity of 232Th is large on the spring and autumn because of strong weathering in Changjiang Basin comparison with other seasons. Compared with the other estuaries in the world, the flux of 238U and 232Th of the Changjiang River estuary is large because of its large fluxes of sediments and runoff in the world. (authors)

  2. Greigite in Holocene sediments of the Yangtze River delta and implications for land-sea transition

    Science.gov (United States)

    Zhang, W.; Dong, Y.; Ye, L.; Yu, L.

    2013-12-01

    Magnetic measurements, geochemical analysis along with scanning electron microscopy (SEM) and X-ray diffractive spectrometry (XRD) analyses were carried out on Holocene deposits from the Yangtze delta to understand the diagenesis of greigite in a coastal environment. Presence of greigite is associated with salt mashes facies, which contains higher total organic carbon (TOC), total sulfur (TS) contents and lower TOC/TS ratio. The salt marshes facies develop both in the Holocene transgressive and regressive stages. However, the thickness of salt marsh layer varies with site and depth, which controls the occurrence of greigite. During the transgressive stage, when the salt marsh show a rapid accretion due to rapid sea-level rise during mid-Holocene, salt marsh deposits is thicker and therefore layer with greigite occurrence is also thicker. When the coast progradates rapidly during the late Holocene under a relative stable sea-level, the salt marsh facies with greigite occurrence is thinner. Such occurrence of greigite in coastal sediments has important implications in the interpretation of sea-level change and geomorphological evolution.

  3. Key Techniques for Design of Edong Changjiang River Highway Bridge%鄂东长江公路大桥设计关键技术

    Institute of Scientific and Technical Information of China (English)

    胡明义; 黄冰释; 余俊林; 唐守峰

    2011-01-01

    The main bridge of Edong Changjiang River Highway Bridge is a semi-floating system hybrid girder cable-stayed bridge with double pylons, double cable planes and with a main span 926 m. The main girder of the bridge was designed as the PK (Pasco-Kennewick Bridge) cross section of separated twin boxes, of which the part of the girder for the central span is of the steel box girder, the parts of the girder for the side spans are of the prestressed concrete (PC) box girders and a steel and concrete joint section was set on each side of the central span at a distance of 12. 5 m to the center of a pylon. To ensure a smooth transition between the steel and concrete structure, the multi-cell force transmission structure with PBL shear connectors was used for the joint section. The cable-to-pylon anchorage is the steel anchor box structure built in the column of a pylon. To control the development of concrete cracks in the anchorage zone in the pylon, the prestressing strands of 12φs 15. 24 were set in the concrete pylon wall on the side of the anchorage. To enhance the structural durability and service life, the durability of reinforced concrete and corrosion protection of steel structure were designed and the life cycle cost concept was applide to the design. The inspection and maintenance accesses for all principal components of the bridge were provided and the inspection and maintenance cycles, replacement criteria, workmanship and technical requirements were formulated as well.%鄂东长江公路大桥主桥为主跨926 m的双塔双索面半飘浮体系混合梁斜拉桥,主梁采用分离式双箱PK断面形式,中跨为钢箱梁,边跨为PC箱梁,钢-混凝土结合段设于中跨距桥塔中心12.5m处.为使钢结构与混凝土结构平稳过渡,钢-混凝土结合段采用PBL剪力连接器的多格室传力构造.索塔锚固采用在塔柱内置钢锚箱的构造,为控制锚固区混凝土裂缝开展,在锚固侧混凝土塔壁内设置12(o)s15.24预应力

  4. The diel rhythms of biosonar behavior in the Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis in the port of the Yangtze River: The correlation between prey availability and boat traffic.

    Directory of Open Access Journals (Sweden)

    Zhitao Wang

    Full Text Available Information on the habitat use of the critically endangered Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis is critical for its conservation. The diel biosonar behavior of the porpoise in the port areas of the Yangtze River was examined along with simultaneous observations of fish density and boat traffic. Biosonar pulses from the porpoises were detected for 1233 min (5.77% over a 21,380 min duration of effective observations. In total, 190 (5.63% buzzes (an indication of prey capture attempts were recorded among the 3372 identified click trains. Of the 168 echolocation encounters (bouts of click trains less than eight min apart, 150 (89.3% involved single animals, indicating that solitary porpoises were frequently present and feeding in the port areas. Significant diel patterns were evident involving the biosonar behavior of the porpoises (including click trains and buzzes, fish density and boat traffic. The frequencies of the click trains and buzzes were significantly lower during the day than in the evening and at night, which suggests that porpoises in this region are primarily engaged in crepuscular and nocturnal foraging. The lack of a significant diel pattern in the echolocation encounters indicates the importance of the port in porpoise conservation. A forced feeding schedule may be associated with the lack of a significant correlation between porpoise acoustics and boat traffic. Overall, prey availability appears to be the primary factor that attracts porpoises. Additionally, porpoises tend to migrate or remain downstream in the morning and migrate or remain upstream in the evening, most likely to follow their prey. The findings of this study can be used to improve the conservation of the Yangtze finless porpoise.

  5. Spatial-temporal distribution and fuzzy comprehensive evaluation of total phosphorus and total nitrogen in the Yangtze River Estuary.

    Science.gov (United States)

    Liu, Ruimin; Chen, Yaxin; Yu, Wenwen; Xu, Fei; Shen, Zhenyao

    2016-01-01

    Based on water sample data collected from the Yangtze River Estuary (YRE) during four sampling periods in 2010 and 2011, the total nitrogen (TN) and total phosphorus (TP) content were evaluated using the traditional single-factor evaluation (TSE) and the fuzzy comprehensive evaluation (FCE). Statistical analyses showed that the average TN and TP for the four periods were 2.60 mg/L and 0.11 mg/L, respectively. August 2010 showed the lowest TN (1.57 mg/L), and February 2011 showed the highest TP (0.15 mg/L). The annual spatial distribution results indicated that an area of high TN concentration (TN ≥ 3.0 mg/L) occurred in the adjacent sea and increased on an eastward gradient. An area of high TP concentration (TP ≥0.10 mg/L) occurred in the inner YRE and decreased on an eastward gradient. There were significant differences in the results of TSE and FCE. The TSE results only reflected the TN evaluation results for certain locations of the YRE. The FCE method combined the effects of the TN and TP factors, and the results indicate that the Chinese water quality classification of Class 5 was dominant in the YRE. PMID:26901737

  6. Contamination of phthalate esters, organochlorine pesticides and polybrominated diphenyl ethers in agricultural soils from the Yangtze River Delta of China.

    Science.gov (United States)

    Sun, Jianteng; Pan, Lili; Zhan, Yu; Lu, Hainan; Tsang, Daniel C W; Liu, Wenxin; Wang, Xilong; Li, Xiangdong; Zhu, Lizhong

    2016-02-15

    To reveal the pollution status associated with rapid urbanization and economic growth, extensive areas of agricultural soils (approximately 45,800 km(2)) in the Yangtze River Delta of China were investigated with respect to selected endocrine disruptor compounds (EDCs), including phthalate esters (PAEs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs). The residues of sum of 15 PAEs, sum of 15 OCPs and sum of 13 PBDEs were in the range of 167-9370 ng/g, 1.0-3520 ng/g, and film was considered to be an important source of PAEs. Discharge from furniture industry was potential major source of PBDEs in this region. The selected pollutants showed quite different spatial distributions within the studied region. It is worth noting that much higher concentrations of the EDCs were found on the borders between Shanghai and the two neighboring provinces, where agriculture and industry developed rapidly in recent years. Contaminants from both agricultural and industrial activities made this area a pollution hotspot, which should arouse more stringent regulation to safeguard the environment and food security. PMID:26674696

  7. Cost estimate of multi-pollutant abatement from the power sector in the Yangtze River Delta region of China

    International Nuclear Information System (INIS)

    Coal-fired power plants in China have emitted multiple pollutants including sulfur dioxide, nitrogen oxides and fine particulates, contributing to serious environmental impairments and human health issues. To meet ambient air quality standards, the installation of effective pollution control technologies are required and consequently, the cost of installing or retrofitting control technologies is an important economic and political concern. A multi-pollutant control cost model, CoST CE, is developed to calculate the cost of multi-pollutant control strategies in the Yangtze River Delta region (YRD) of China, adopting an LP algorithm to optimize the sorting of control technology costs and quickly obtain a solution. The output shows that total costs will increase along with emission abatement. Meanwhile, the slope becomes steeper as greater emission reductions are pursued, due to the need to install highly effective, but expensive, technologies like SCR and FF. Moreover, it is evident that the cost curve shapes, maximum abatement potential and total cost for the three provinces in the YRD region are quite different due to differences in power plant type and technologies, current emission levels and existing pollution controls. The results from this study can aid policy makers to develop cost-effective control strategies for the power sector

  8. Estimating Emissions and Environmental Fate of Di-(2-ethylhexyl) Phthalate in Yangtze River Delta, China: Application of Inverse Modeling.

    Science.gov (United States)

    Zhan, Yu; Sun, Jianteng; Luo, Yuzhou; Pan, Lili; Deng, Xunfei; Wei, Zi; Zhu, Lizhong

    2016-03-01

    A georeferenced multimedia model was developed for evaluating the emissions and environmental fate of di-2-ethylhexyl phthalate (DEHP) in the Yangtze River Delta (YRD), China. Due to the lack of emission inventories, the emission rates were estimated using the observed concentrations in soil as inputs for the multimedia model solved analytically in an inverse manner. The estimated emission rates were then used to evaluate the environmental fate of DEHP with the regular multimedia modeling approach. The predicted concentrations in air, surface water, and sediment were all consistent with the ranges and spatial variations of observed data. The total emission rate of DEHP in YRD was 13.9 thousand t/year (95% confidence interval: 9.4-23.6), of which urban and rural sources accounted for 47% and 53%, respectively. Soil in rural areas and sediment stored 79% and 13% of the total mass, respectively. The air received 61% of the total emissions of DEHP but was only associated with 0.2% of the total mass due to fast degradation and intensive deposition. We suggest the use of an inverse modeling approach under a tiered risk assessment framework to assist future development and refinement of DEHP emission inventories. PMID:26861906

  9. Dynamics of arsenic in salt marsh sediments from Dongtan wetland of the Yangtze River estuary,China

    Institute of Scientific and Technical Information of China (English)

    Yongjie Wang; Limin Zhou; Xiangmin Zheng; Peng Qian; Yonghong Wu

    2012-01-01

    The mobility and transformation of arsenic (As) in salt marsh sediments were investigated in Dongtan wetland of the Yangtze River estuary,China.As in surface water,pore water and the rhizosphere sediments were quantified.The microcosm incubation experiments were conducted during the flooding of the sediments to examine As dynamics that occurred during changing redox conditions.The concentrations of dissolved As in pore water (0.04-0.95 μmol/L) were significantly greater than that in surface water (0.03-0.06μmol/L).Under anoxic conditions,the reactive As could be initially mobilized by the reductive dissolution of Fe(Ⅲ) (hydr)oxides.Subsequently,most of the dissolved As was likely to be associated with secondary iron (hydr)oxide phases and remained in solid phases.The seasonal variability of acid volatile sulfide concentrations suggest the anoxic conditions are enhanced during summer by Spartina alterniflora compared to Phragmites australis and Scirpus mariqueter,causing a notable increase in As mobility.Generally,there was a typical variation in redox conditions with season in salt marsh sediments of Dongtan wetland,in which the dynamics of As mobility and transformation possibly were controlled by iron,and all of this could be significantly influenced by the rapid spread of S.alterniflora.

  10. Mechanisms for concurrent low-latitude circulation anomalies responsible for persistent extreme precipitation in the Yangtze River Valley

    Science.gov (United States)

    Chen, Yang; Zhai, Panmao

    2016-08-01

    Concurrent position shifts of the mid-level western Pacific subtropical high (WPSH) and the upper-level South Asia high (SAH) are regarded as significant precursors for persistent extreme precipitation events (PEPEs) in the Yangtze River Valley (YRV). By performing composite analyses, accountable vorticity genesis and dissipation are diagnosed based on a potential vorticity-diabatic heating theory. The results indicate that about 1 week preceding precipitation onset, a wave-like pattern of anomalous diabatic heating (Q) initiates its northwestward propagation from equatorial central Pacific. Subsequently, this wave-like pattern induces substantial changes in both horizontal and vertical structure of local Q along the propagating route. Forced negative vorticities in key areas result in the zonal approach between the SAH and the WPSH. During PEPEs, two thermal-induced vertical circulation cells take shape, with common strong ascent centered in the YRV. These anomalous cells are capable of self-maintaining for a few days via positive feedback processes. The WPSH and the SAH are therefore anchored in respective favorable positions for PEPEs. Simultaneously, descending motion of these two cells increases local solar radiation and decreases upward latent heat flux from surface, facilitating warmer underlying surface and swift accumulation of lower-level moisture. Correspondingly, enhanced heating to the north and rapid developing cyclone over warmer sea surface to the south combine to terminate above positive feedback processes. Finally, both the WPSH and the SAH retreat to their normal positions, accompanied by a quick decay of PEPEs.

  11. Technical difficulties and innovation in the Jiangyin Yangtze River crossing project of 3300 m HDD

    Directory of Open Access Journals (Sweden)

    Wu Yiquan

    2014-10-01

    Full Text Available The Jiangyin Yangtze River Crossing Project sets up a record with the length of horizontal directional drilling (HDD of 3300 m in the world. Inevitably, many technical difficulties might exist in pilot hole docking, reaming torque, property requirement and recovery of drilling fluids, and pullback resistance. Accordingly, some innovative measures were taken in each stage. At the pilot hole drilling stage, a reasonable drill tool assembly was chosen, namely, a new type of Ø 193.7 mm (S-135 drill pipe with high-strength was applied along with the fully guided cable and rotating magnate docking technologies. At the reaming stage, an innovative Ø 168.3 mm (V-150 drill pipe was adopted along with the optimized reamers and the improved hydraulic parameters to successfully reduce the reaming torque and significantly improve the reaming efficiency. At the pullback stage, a specific ground anchor was designed for large-tonnage pullback resistance, and drift pipe, super lubricants and novel glass fiber reinforced plastics were combined for protecting the pipeline coating. Finally, the drilling fluid formula was optimally selected to ensure the hole stability and flowback of drilling cuttings, and a centrifugal was used to recycle the drilling mud to ensure its necessary performance. All these measures not only ensured the success of this HDD project, but also broke many records in this respect.

  12. Variation of GPS Precipitable Water over the Qinghai-Tibet Plateau: Possible Teleconnection Triggering Rainfall over the Yangtze River Valley

    Directory of Open Access Journals (Sweden)

    Gui-Rong Xu

    2011-01-01

    Full Text Available GPS technologies show many capabilities for monitoring atmospheric water vapor. This study uses GPS data from the Japan International Co-operation Agency (JICA and Hubei GPS network to monitor precipitable water (PW over the Qinghai-Tibet Plateau (QTP and over the middle Yangtze River Valley (YRV. The results show that the southern QTP is wetter than the central area due to the barring effect of the Plateau on the monsoon. PW is higher in summer than other months over either the QTP or the middle YRV. The diurnal variation of PW over the QTP is more complex than that of the middle YRV with fluctuations occurring during the whole day due to the unique topography. The minimum PW over both the QTP and the middle YRV appears in the morning; however, the peak over the QTP occurs at night while the peak over the middle YRV occurs in the early afternoon. Furthermore, PW over the QTP, especially its southern and eastern edges, are positively correlated with PW over the middle YRV. This may imply that the southern and eastern Plateaus are key regions transporting atmospheric vapor to the middle YRV. Our results indicate the possibility of finding early warning signals resulting from the intensification of the QTP atmospheric vapor leading to heavy rainfall events over the middle YRV.

  13. Long-term trend of haze pollution and impact of particulate matter in the Yangtze River Delta, China.

    Science.gov (United States)

    Cheng, Zhen; Wang, Shuxiao; Jiang, Jingkun; Fu, Qingyan; Chen, Changhong; Xu, Bingye; Yu, Jianqiao; Fu, Xiao; Hao, Jiming

    2013-11-01

    Haze pollution caused by heavy particulate matter (PM) loading brings significant damage in eastern China. Long-term monitoring from 1980 to 2011 and 1-year field measurement in 2011-2012 are used for investigating visibility variation and the impact of PM pollution for the Yangtze River Delta (YRD). It was found that visual range in the YRD endured a sharp reduction from 13.2 km to 10.5 km during 1980-2000. Average mass extinction efficiency (MEE) for inhalable PM (PM10) is 2.25 m(2)/g in 2001-2011, and extinction coefficient due to PM10 is 207 Mm(-1), accounting for 36.2% of total extinction coefficient. MEE of PM2.5 and PM2.5-10 are 4.08 m(2)/g and 0.58 m(2)/g, respectively. Extinction coefficient due to PM2.5 and PM2.5-10 is 198 Mm(-1) (39.6%) and 20 Mm(-1) (4.0%) in 2011-2012. Maximum daily concentration of PM10 and PM2.5 is estimated to be 63 μg/m(3) (RH: 73%) and 38 μg/m(3) (RH: 70%) to keep visual range above 10 km. Fine particulate matter is the key factor for haze pollution improvement in the YRD area. PMID:23906557

  14. Farmers’ Sustainable Strategies for Soil Conservation on Sloping Arable Lands in the Upper Yangtze River Basin, China

    Directory of Open Access Journals (Sweden)

    Qiang Tang

    2014-07-01

    Full Text Available The Upper Yangtze River Basin comprises a densely-populated agricultural region with mountainous and hilly landforms. Intensive cultivation has been extended onto steep hillslopes, which constitute the principal source area for sediment production. Soil conservation on sloping arable lands is thus of utmost priority for persisting sustainable agricultural production and maintaining sound ecosystem services. Although there have been many soil conservation techniques, either promoted by the government or adopted by local farmers, the practiced area was very limited relative to the total area affected by soil erosion. This paper attempts to introduce four popular soil conservation measures on sloping arable lands in this region to enhance a broader scale of implementation, including hedgerow buffers, level trenches, sloping terraces and limited downslope tillage. These practices, although developed from local farmers’ indigenous knowledge for productive purposes, have well conformed to our contemporary understanding of soil erosion processes on sloping landscape affected by human disturbances, were of sound suitability to regional manual tillage agriculture and more trade-off-efficient on rill prevention, runoff harvest and nutrient management.

  15. [Abundance distribution of virioplankton in Yangtze River estuary and its adjacent East China Sea in summer and winter].

    Science.gov (United States)

    Liu, Jing-jing; Zeng, Jiang-ning; Du, Ping; Chen, Quan-zhen

    2011-03-01

    An investigation was made on the abundance distribution and its variation of virioplankton in the Yangtze River estuary and its adjacent East China Sea in summer 2006 and winter 2007. The virus direct count (VDC) was quantified by fluorescent microscopy. In summer 2006, the VDC was from 2.22 x 10(6) to 9.97 x 10(7) ind x m(-1), being higher in the surface sea water of B area (122.5 degrees-123.5 degrees E); in winter 2007, the VDC was from 1.99 x 10(6) to 2.66 x 10(7) ind x mh(-1), being higher in coastal A area (120.5 degrees-122.5 degrees E) and decreased from nearshore waters to offshore waters. In summer, the VDC had close relationships with bacteriaplankton biomass and chlorophylla concentration but less relationship with nutrients concentration (P > 0.05); in winter, the VDC was closely related to bacteriaplankton biomass and nutrients concentration but less related to chlorophyll-a concentration (P > 0.05). The abundance distribution pattern of virioplankton showed significant seasonal variability, with the VDC significantly larger in summer than in winter (P < 0.01), which was mainly decided by the distribution of the viral host, and partly by the nutrients concentration in wintertime. PMID:21657040

  16. Establishment and Application of the Wind and Structural Health Monitoring System for the Runyang Yangtze River Bridge

    Directory of Open Access Journals (Sweden)

    Hao Wang

    2014-01-01

    Full Text Available Structural health monitoring can provide a practical platform for detecting the evolution of structural damage or performance deterioration of engineering structures. The final objective is to provide reasonable suggestions for structural maintenance and management and therefore ensure the structural safety according to the real-time recorded data. In this paper, the establishment of the wind and structural health monitoring system (WSHMS implemented on the Runyang Yangtze River Bridge (RYRB in China is introduced. The composition and functions of the WSHMS are presented. Thereinto, the sensory subsystem utilized to measure the input actions and structural output responses is introduced. And the core functions of the data management and analysis subsystem (DMAS including model updating, structural condition identification, and structural condition assessment are illustrated in detail. A three-stage strategy is applied into the FE model updating of RYRB, and a two-phase strategy is proposed to adapt to structural health diagnosis and damage identification. Considering the structural integral security and the fatigue characteristic of steel material, the condition assessment of RYRB is divided into structural reliability assessment and structural fatigue assessment, which are equipped with specific and elaborate module for effective operation. This research can provide references for the establishment of the similar structural health monitoring systems on other cable-supported bridges.

  17. Organic Phosphorus in Shallow Lake Sediments in Middle and Lower Reaches of the Yangtze River Area in China

    Institute of Scientific and Technical Information of China (English)

    JIN Xiang-Can; WANG Sheng-Rui; CHU Jian-Zhou; WU Feng-Chang

    2008-01-01

    Thirteen sediment core samples (0-10 cm) were taken from the seven lakes in the middle and lower reaches of the Yangtze River to determine the contents and distributions of organic phosphorus (P) fractions in the sediments of the shallow lakes in the area.The organic P fractions in the sediments were in the order of moderately labile organic P (MLOP) > moderately resistant organic P (MROP) > highly resistant organic P (HROP) > labile organic P (LOP),with average proportional ratios of 13.2:2.8:1.3:1.0.LOP,MLOP,and MROP were significantly related to the contents of total organic carbon (TOC),water-soluble P (WSP),algal-available P (AAP),NaHCO3-extractable P (Olsen-P),total P (TP),organic P (OP),and inorganic P (IP).However,HROP was significantly related to OP and weakly correlated with TOC,WSP,AAP,Olsen-P,TP or IP.This suggested that organic P,especially LOP and MLOP in sediments,deserved even greater attention than IP in regards to lake eutrophication.In terms of organic P,sediments were more hazardous than soils in lake eutrophication.Although OP concentrations were higher in moderately polluted sediment than those in heavily polluted sediment,LOP and MLOP were higher in the heavily polluted sediment,which indicated that heavily polluted sediment was more hazardous than moderately polluted sediment in lake eutrophication.

  18. Seasonal variation effects on the formation of trihalomethane during chlorination of water from Yangtze River and associated cancer risk assessment

    Institute of Scientific and Technical Information of China (English)

    Shaogang Liu; Zhiliang Zhu; Chenfeng Fan; Yanling Qiu; Jianfu Zhao

    2011-01-01

    For the system of water samples collected from Yangtze River,the effects of seasonal variation and Fe(Ⅲ) concentrations on the formation and distribution of trihalomethanes (THMs) during chlorination have been investigated.The corresponding lifetime cancer risk of the formed THMs to human beings was estimated using the parameters and procedure issued by the US EPA.The results indicated that the average concentration of THMs (100.81 μg/L) in spring was significantly higher than that in other seasons,which was related to the higher bromide ion concentration resulted from the intrusion of tidal saltwater.The total cancer risk in spring reached 8.23 × 10-5 and 8.86 × 10-5 for males and females,respectively,which were about two times of those in summer under the experimental conditions.Furthermore,it was found that the presence of Fe(Ⅲ) resulted in the increased level of THMs and greater cancer risk from exposure to humans.Under weak basic conditions,about 10% of the increment of THMs from the water samples in spring was found in the presence of 0.5 mg/L Fe(Ⅲ) compared with the situation without Fe(Ⅲ).More attention should be given to the effect of the coexistence of Fe(Ⅲ) and bromide ions on the risk assessment of human intake of THMs from drinking water should be paid more attention,especially in the coastland and estuaries.

  19. Winter temperature variations over middle and lower reaches of the Yangtze River during the past three centuries

    Science.gov (United States)

    Hao, Z.-X.; Zheng, J.-Y.; Ge, Q.-S.; Wang, W.-C.

    2012-01-01

    We present statistically reconstructed annual winter (December-February) mean temperature in the Middle and Lower Reaches of the Yangtze River (24-34° N, east of 108° E) back to 1736. The reconstructions are based on information from snowfall days from Yu-Xue-Fen-Cun archive (one of historical documents proxies) in Qing Dynasty (1644-1911). Those information are calibrated with regional winter temperature series spanning the period 1951 to 2007 period. The gap from 1912 to 1950 is filled using early instrumental observation. With respect to the 1951-2007 climatology, the 18th century was 0.6 °C colder, and the 19th century was 1.0 °C colder. But since the 20th century, climate entered into the warming phase, particular in the last 30 yr, the mean temperature from 1981 to 2007 is 0.25 °C higher than that of climatology, a highest level of the past 300 yr. The uncertainty is existed for the period prior of 1900, and possible causes have been discussed here.

  20. Winter temperature variations over middle and lower reaches of the Yangtze River during the past three centuries

    Directory of Open Access Journals (Sweden)

    Z.-X. Hao

    2012-01-01

    Full Text Available We present statistically reconstructed annual winter (December–February mean temperature in the Middle and Lower Reaches of the Yangtze River (24–34° N, east of 108° E back to 1736. The reconstructions are based on information from snowfall days from Yu-Xue-Fen-Cun archive (one of historical documents proxies in Qing Dynasty (1644–1911. Those information are calibrated with regional winter temperature series spanning the period 1951 to 2007 period. The gap from 1912 to 1950 is filled using early instrumental observation. With respect to the 1951–2007 climatology, the 18th century was 0.6 °C colder, and the 19th century was 1.0 °C colder. But since the 20th century, climate entered into the warming phase, particular in the last 30 yr, the mean temperature from 1981 to 2007 is 0.25 °C higher than that of climatology, a highest level of the past 300 yr. The uncertainty is existed for the period prior of 1900, and possible causes have been discussed here.

  1. Approximating actual flows in physical infrastructure networks: the case of the Yangtze River Delta high-speed railway network

    Directory of Open Access Journals (Sweden)

    Zhang Weiyang

    2016-03-01

    Full Text Available Previous empirical research on urban networks has used data on infrastructure networks to guesstimate actual inter-city flows. However, with the exception of recent research on airline networks in the context of the world city literature, relatively limited attention has been paid to the degree to which the outline of these infrastructure networks reflects the actual flows they undergird. This study presents a method to improve our estimation of urban interaction in and through infrastructure networks by focusing on the example of passenger railways, which is arguably a key potential data source in research on urban networks in metropolitan regions. We first review common biases when using infrastructure networks to approximate actual inter-city flows, after which we present an alternative approach that draws on research on operational train scheduling. This research has shown that ‘dwell time’ at train stations reflects the length of the alighting and boarding process, and we use this insight to estimate actual interaction through the application of a bimodal network projection function. We apply our method to the high-speed railway (HSR network within the Yangtze River Delta (YRD region, discuss the difference between our modelled network and the original network, and evaluate its validity through a systemic comparison with a benchmark dataset of actual passenger flows.

  2. Effect of river discharge and geometry on tides and net water transport in an estuarine network, an idealised model applied to the Yangtze Estuary

    Science.gov (United States)

    de Swart, Huib E.; Alebregtse, Niels C.

    2015-04-01

    Many estuaries in the world show a complex pattern of interconnected branches. The water motion in these estuarine networks is dominated by tides and by net water transport, the latter being primarily forced by river discharge and by nonlinear tidal rectification processes. The behaviour of tides (sea surface height and currents) and the distribution of net water transport over the branches is an important topic of research, e.g. for flushing of pollutants, salinity intrusion and sediment transport. Field observations, e.g. in the Yangtze Estuary, show that tides and distribution of net water transport over the branches are highly sensitive to river discharge (wet and dry season) and to changes in geometry, e.g. due to navigational works. To understand such sensivities, this contribution presents a semi-analytical model that yields explicit solutions for tides and net water transport for arbitrary tidal network configurations. The model accounts for tide-river interactions, which in particular affect friction, and for tidal rectification processes. The model is subsequently applied to the Yangtze Estuary. It will be shown that tide-river interactions are crucial to understand the observed differences in tidal propagation between the wet and dry season. Furthermore, the relative increase of the net water transport driven by tidal rectification with respect to that driven by river discharge explains the observed differences in distribution of water transport over the branches between wet and dry season in this estuary. Finally, it will be shown that the construction of navigational works resulted in an increase of tidal currents, a decrease of net water transport and an increase in ebb-dominance in the North Passage of the Yangtze Estuary, consistent with observations.

  3. Contribution of the upper river, the estuarine region, and the adjacent sea to the heavy metal pollution in the Yangtze Estuary.

    Science.gov (United States)

    Yin, Su; Wu, Yuehan; Xu, Wei; Li, Yangyang; Shen, Zhenyao; Feng, Chenghong

    2016-07-01

    To determine whether the discharge control of heavy metals in the Yangtze River basin can significantly change the pollution level in the estuary, this study analyzed the sources (upper river, the estuarine region, and the adjacent sea) of ten heavy metals (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, and Zn) in dissolved and particulate phases in the surface water of the estuary during wet, normal, and dry seasons. Metal sources inferred from section fluxes agree with those in statistical analysis methods. Heavy metal pollution in the surface water of Yangtze Estuary primarily depends on the sediment suspension and the wastewater discharge from estuary cities. Upper river only constitutes the main source of dissolved heavy metals during the wet season, while the estuarine region and the adjacent sea (especially the former) dominate the dissolved metal pollution in the normal and dry seasons. Particulate metals are mainly derived from sediment suspension in the estuary and the adjacent sea, and the contribution of the upper river can be neglected. Compared with the hydrologic seasons, flood-ebb tides exert a more obvious effect on the water flow directions in the estuary. Sediment suspension, not the upper river, significantly affects the suspended particulate matter concentration in the estuary. PMID:27155472

  4. Quantifying uncertainty in the impacts of climate change on river discharge in sub-catchments of the Yangtze and Yellow River Basins, China

    Directory of Open Access Journals (Sweden)

    H. Xu

    2011-01-01

    Full Text Available Quantitative evaluations of the impacts of climate change on water resources are primarily constrained by uncertainty in climate projections from GCMs. In this study we assess uncertainty in the impacts of climate change on river discharge in two catchments of the Yangtze and Yellow River Basins that feature contrasting climate regimes (humid and semi-arid. Specifically we quantify uncertainty associated with GCM structure from a subset of CMIP3 AR4 GCMs (HadCM3, HadGEM1, CCSM3.0, IPSL, ECHAM5, CSIRO, CGCM3.1, SRES emissions scenarios (A1B, A2, B1, B2 and prescribed increases in global mean air temperature (1 °C to 6 °C. Climate projections, applied to semi-distributed hydrological models (SWAT 2005 in both catchments, indicate trends toward warmer and wetter conditions. For prescribed warming scenarios of 1 °C to 6 °C, linear increases in mean annual river discharge, relative to baseline (1961–1990, for the River Xiangxi and River Huangfuchuan are +9% and 11% per +1 °C respectively. Intra-annual changes include increases in flood (Q05 discharges for both rivers as well as a shift in the timing of flood discharges from summer to autumn and a rise (24 to 93% in dry season (Q95 discharge for the River Xiangxi. Differences in projections of mean annual river discharge between SRES emission scenarios using HadCM3 are comparatively minor for the River Xiangxi (13 to 17% rise from baseline but substantial (73 to 121% for the River Huangfuchuan. With one minor exception of a slight (−2% decrease in river discharge projected using HadGEM1 for the River Xiangxi, mean annual river discharge is projected to increase in both catchments under both the SRES A1B emission scenario and 2° rise in global mean air temperature using all AR4 GCMs on the CMIP3 subset. For the River Xiangxi, there is substantial uncertainty associated with GCM structure in the magnitude of the rise in flood (Q05 discharges (−1 to 41% under SRES A1B and −3 to 41% under 2

  5. 长江中游马口-田家镇河段40年来河道演变%Channel changes of the Makou-Tianjiazhen reach in the middle Yangtze River during the past 40 years

    Institute of Scientific and Technical Information of China (English)

    张强; 陈永勤; 姜彤; 李茂田

    2007-01-01

    Quantitative analysis was performed on the filling-scouring process for the river reach within Makou and Tianjiazhen, the middle Yangtze River with the help of GIS and DEM techniques. The research results indicate that the river reach between Makou and Tianjiazhen was dominated by the scouring process, and the magnitude of scouring is increasing over time. The intensity of scouring process is more in the deep and narrower river reach than shallower and wider ones. The river reach in the Makou and Tianjiazhen river knot is in frequent scouring and filling process, however the river reach upper to the Makou and lower to the Tianjiazhen river knot is in moderate scouring and filling process. The river reach just upstream or downstream to the river knot (e.g. Makou and Tianjiazhen river knot in this research) is dominated by filling process and the river reach in the river knot is dominated by the scouring process. Research results indicate no changes in the boundary of the river but the scouring and the filling magnitude in specific river channel is strong. The filling and the scouring process of the study river reach is greatly impacted by the sediments and water from the upstream of the study river reach. The construction of the Three Gorges Dam just upstream to Yichang will cause further decrease of the release of the sediment load to the middle and the lower Yangtze River basin, which will further intensify the scouring process of the river channel in the study river reach.

  6. Algal community composition and abundance near the confluence of the Jialing and Yangtze Rivers and in Shuanglong Lake in Chongqing, P.R.China

    Institute of Scientific and Technical Information of China (English)

    GUO Wei-hua; HE Dong-cai; LONG Tian-yu; LI Nan; DAI Ling-ling

    2008-01-01

    To understand the potential impact of the Three Gorges Reservoir on the aquatic ecosystem after the damming of the Yangtze River, we studied the community composition and temporal abundance distribution of algae in two types of water bodies:a segment of the Jialing River near its confluence with the Yangtze River as an example of the river-lake type, and Shuanglong Lake in Chongqing as an example of the lake type. In total, 107 species belonging to 58 genera of 7 phyla were identified in the study area of the Jialing River, dominated by three groups with 49.5% diatoms, 29.0% chlorophytes, and 11.4% cyanobacteria in the community composition. There were 122 species belonging to 66 genera of 8 phyla in Shuanglong Lake, dominated by the same three groups with 19.7% diatoms, 48.4% chlorophytes, and 22.2% cyanobacteria. The densities of total algae and individual dominant groups were all much higher in the lake. More species of diatoms were found in the river-lake segment; whereas more chlorophyte species and cyanobacteriaum species were in the lake. There were 17 dominant species including 8 diatoms, 4 chlorophytes, 3 cyanobacteria and 2 cryptophytes in the river-lake segment, and 21 species in the lake, including 2 diatoms, 9 chlorophytes, 6 cyanobacteria, 3 cryptophytes and a dinoflagellate. In eutrophic conditions, chlorophytes and cyanobacteria mayproliferate in a lake-type area and diatoms may cause algal bloom in a relatively faster-flow lake-river type area.

  7. Long-term variations in dissolved silicate, nitrogen, and phosphorus flux from the Yangtze River into the East China Sea and impacts on estuarine ecosystem

    Science.gov (United States)

    Li, Maotian; Xu, Kaiqin; Watanabe, Masataka; Chen, Zhongyuan

    2007-01-01

    Variations of dissolved silicate (DSi) flux in the Yangtze River have caused great concern among scientists. Analysis of spatial and temporal variations of DSi indicates that the distribution of DSi concentration (DSiC) is closely related to the occurrence of bedrocks in the river cathchment. On average, the upper Yangtze River and Dongting and Poyang Lake of the middle Yangtze basin serve as the major DSi sinks, retaining 3.39 × 10 4 t y -1, 5.59 × 10 4 and 2.51 × 10 4 t y -1. The middle and low Yangtze River remains DSi sources, emitting 2.85 × 10 4 and 2.48 × 10 4 t y -1, respectively. Geochemical data at Datong hydrological station recorded the flux of nutrients entering into the sea during the flood season, i.e. 74% for DSi, 73% for DIN (Dissolved Inorganic Nitrate) and 68% DIP (Dissolved Inorganic Phosphate). The yearly DSiC and flux show a sharp decrease since 1950s. The mean DSiC was 109.47, 91.09, and 77.56 μmol l -1 in the 1960s, 1970s and 1980s, respectively. The mean DSi fluxes for the same time period were 2.72, 2.23, and 2.13 × 10 6 t. A PP (primary productivity) model estimates 3.14 × 10 5 t of DSi (13.08% of the annual mean flux entering into the sea) was fixated within the 162 reservoirs in 2002. On the other hand, DIN and DIP concentration and flux have increased greatly since the 1950s. Fertilizer application peaked after the 1980s can interpret these high DIN and DIP. A sharply decreasing DSi flux and quickly increasing DIN and DIP fluxes into the sea have enhanced eutrophication and caused frequent harmful algal blooms in coastal waters. On average, red-tide frequency was from 0.04 during 1933-1979 to 7.0 during 2000-2002. The Skeletonema costatum (siliceous alga), the red-tide-predominant species that is in positive proportion to DSi flux, decreased from 33% during the 1980s to 24% during 2000-2002. The present data evidence the increase of Prorocentrum dentatum (non-siliceous alga) from 12.5% in the 1980s to 36% in 2000-2002, which

  8. Linking Three Gorges Dam and downstream hydrological regimes along the Yangtze River, China

    NARCIS (Netherlands)

    Mei, X.; Dai, Z.; Van Gelder, P.H.A.J.M.; Gao, J.

    2015-01-01

    The magnitude of anthropogenic influence, especially dam regulation, on hydrological system is of scientific and practical value for large river management. As the largest dam in the world by far, Three Gorges Dam (TGD) is expected to be a strong evidence on dam impacts on downstream hydrological re

  9. Molecular characterization of atmospheric particulate organosulfates in three megacities at the middle and lower reaches of the Yangtze River

    Science.gov (United States)

    Wang, Xin Ke; Rossignol, Stéphanie; Ma, Ye; Yao, Lei; Wang, Ming Yi; Chen, Jian Min; George, Christian; Wang, Lin

    2016-02-01

    PM2.5 filter samples have been collected in three megacities at the middle and lower reaches of the Yangtze River: Wuhan (WH), Nanjing (NJ), and Shanghai (SH). The samples were analyzed using ultra-high-performance liquid chromatography (UHPLC) coupled with Orbitrap mass spectrometry (MS), which allowed for detection of about 200 formulas of particulate organosulfates (OSs), including dozens of formulas of nitrooxy-organosulfates, with various numbers of isomers for each tentatively determined formula at each location. The number of aliphatic OS formulas represented more than 78 % of the detected OSs at the three locations, while aromatic OSs were much less numerous. OSs with two to four isomers accounted for about 50 % of the total OSs on average in these megacity samples, and the percentage of OSs with six and more isomers in the WH sample was more significant than those in the SH and NJ samples. Additionally, the molecular formula, average molecular weight, and degrees of oxidation and unsaturation of tentatively assigned OSs were compared. The results indicate that the OSs between NJ and SH shared higher similarity, and the characteristics of OSs in SH varied diurnally and seasonally. OSs derived from isoprene, monoterpenes, and sesquiterpenes were abundant in samples from the three megacities and could be produced through both daytime photochemistry and NO3 night-time chemistry. The reaction pathways leading to isoprene-derived OSs probably varied in those locations because of the different NOx levels. In addition, a number of OSs that might be formed from polycyclic aromatic hydrocarbons were also detected, which underlies the importance of anthropogenic sources for this class of compounds.

  10. Assessment on the vulnerability of different ecosystems to extreme rainfalls in the middle and lower reaches of Yangtze River

    Science.gov (United States)

    Yongxiang, Zhang; Bo, Tao; Li, Yu

    2015-07-01

    The vulnerability of major ecosystems to extreme rainfalls was investigated across the middle and lower reaches of the Yangtze River, China, during 1961-2000, by using an improved process-based model (Carbon Exchange between Vegetation, Soil, and Atmosphere, CEVSA). The simulated Net Primary Productivity (NPP) was selected as the indicator to identify impacts of extreme rainfalls on ecosystem functioning. The changing characteristics of the NPP in the five extreme rainfall years are employed to represent the sensitivity and adaptive capacity of ecosystems to extreme rainfalls events. The vulnerability of major ecosystems to extreme rainfalls was then examined by comparing with the averaged status during 1961-1990. Our results suggest that the relatively lower and higher vulnerable agro-ecosystems were mainly distributed in the central and northwest of the study area. The proportions of high and very high vulnerable agro-ecosystems to rainfall were about 19 and 5 % of the total area. For the forest ecosystem, the lower vulnerability mainly occurred in the south, while the higher vulnerability happened in the north of the study area which had taken about 15 % of the high vulnerable level and about 2 % of the very high vulnerable level. The extreme rainfalls enhanced the vulnerability both of agro-ecosystems and forest ecosystems. The vulnerability of agro-ecosystems to droughts was higher than that of forest ecosystems, while the vulnerability of forest ecosystems to floods was higher than that of agro-ecosystems. Our study demonstrates that both human-dominated (e.g., agro-ecosystem) and natural ecosystems are vulnerable to extreme climatic events. Future warming climate might further worsen the ecosystem sustainability in this area if no mitigation and adaptation measures are adopted.

  11. Interdecadal Connection Between Artic Temperature and Summer Precipitation Over the Yangtze River Valley in the CMIP5 Historical Simulations

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yuefeng; Leung, Lai-Yung R.; Xiao, Ziniu; Wei, Min; Li, Qingquan

    2013-10-01

    This study assesses the ability of the Phase 5 Coupled Model Intercomparison Project (CMIP5) simulations in capturing the interdecadal precipitation enhancement over the Yangtze River valley (YRV) and investigates the contributions of Arctic warming to the interdecadal variability of the East Asian summer monsoon rainfall. Six CMIP5 historical simulations including models from Canada (CCCma), China (BCC), Germany (MPI-M), Japan (MRI), United Kingdom (MOHC), and United States (NCAR) are used. The NCEP/NCAR reanalysis and observed precipitation are also used for comparison. Among the six CMIP5 simulations, only CCCma can approximately simulate the enhancement of interdecadal summer precipitation over the YRV in 1990-2005 relative to 1960-1975, and the relationships between the summer precipitation with surface temperature (Ts), the 850hPa winds, and 500hPa height field (H500), and between Ts and H500 using regression, correlation, and SVD analyses. It is found that CCCma can reasonably simulate the interdecadal surface warming over the boreal mid-to high latitudes and the Arctic in winter, spring and summer. The summer Baikal blocking appears to be the bridge that links the winter and spring surface warming over the mid-to high latitude and Arctic with the enhancement of summer precipitation over the YRV. Models that missed some or all of these relationships found in CCCma and the reanalysis failed to simulate the interdecadal enhancement of precipitation over the YRV. This points to the importance of high latitude and Arctic processes on interdecadal variability of the East Asian summer monsoon and the challenge for global climate models to correctly simulate the linkages.

  12. Reserve network planning for fishes in the middle and lower Yangtze River basin by systematic conservation approaches.

    Science.gov (United States)

    Huang, Xinyi; Li, Fan; Chen, Jiakuan

    2016-03-01

    Although China has established more than 600 wetland nature reserves, conservation gaps still exist for many species, especially for freshwater fishes. Underlying this problem is the fact that top-level planning is missing in the construction of nature reserves. To promote the development of nature reserves for fishes, this study took the middle and lower reaches of the Yangtze River basin (MLYRB) as an example to carry out top-level reserve network planning for fishes using approaches of systematic conservation planning. Typical fish species living in freshwater habitats were defined and considered in the planning. Based on sample data collected from large quantities of literatures, continuous distribution patterns of 142 fishes were obtained with species distribution modeling and subsequent processing, and the distributions of another eleven species were artificially designated. With the distribution pattern of species, Marxan was used to carry out conservation planning. To obtain ideal solutions with representativeness, persistence, and efficiency, parameters were set with careful consideration regarding existing wetland reserves, human disturbances, hydrological connectivity, and representation targets of species. Marxan produced the selection frequency of planning units (PUs) and a best solution. Selection frequency indicates the relative protection importance of a PU. The best solution is a representative of ideal fish reserve networks. Both of the PUs with high selection frequency and those in the best solution have low proportions included in existing wetland nature reserves, suggesting that there are significant conservation gaps for fish species in MLYRB. The best solution could serve as a reference for establishing a fish reserve network in the MLYRB. There is great flexibility for replacing selected PUs in the solution, and such flexibility facilitates the implementation of the solution in reality in case of unexpected obstacles. Further, we suggested

  13. Effectiveness of maritime safety control in different navigation zones using a spatial sequential DEA model: Yangtze River case.

    Science.gov (United States)

    Wu, Bing; Wang, Yang; Zhang, Jinfen; Savan, Emanuel Emil; Yan, Xinping

    2015-08-01

    This paper aims to analyze the effectiveness of maritime safety control from the perspective of safety level along the Yangtze River with special considerations for navigational environments. The influencing variables of maritime safety are reviewed, including ship condition, maritime regulatory system, human reliability and navigational environment. Because the former three variables are generally assumed to be of the same level of safety, this paper focuses on studying the impact of navigational environments on the level of safety in different waterways. An improved data envelopment analysis (DEA) model is proposed by treating the navigational environment factors as inputs and ship accident data as outputs. Moreover, because the traditional DEA model cannot provide an overall ranking of different decision making units (DMUs), the spatial sequential frontiers and grey relational analysis are incorporated into the DEA model to facilitate a refined assessment. Based on the empirical study results, the proposed model is able to solve the problem of information missing in the prior models and evaluate the level of safety with a better accuracy. The results of the proposed DEA model are further compared with an evidential reasoning (ER) method, which has been widely used for level of safety evaluations. A sensitivity analysis is also conducted to better understand the relationship between the variation of navigational environments and level of safety. The sensitivity analysis shows that the level of safety varies in terms of traffic flow. It indicates that appropriate traffic control measures should be adopted for different waterways to improve their safety. This paper presents a practical method of conducting maritime level of safety assessments under dynamic navigational environment. PMID:25591393

  14. Examining the major contributors of ozone pollution in a rural area of the Yangtze River Delta region during harvest season

    Science.gov (United States)

    Pan, X.; Kanaya, Y.; Tanimoto, H.; Inomata, S.; Wang, Z.; Kudo, S.; Uno, I.

    2015-06-01

    Open biomass burning (OBB) emits significant amounts of non-methane hydrocarbons (NMHCs), and the mixing of OBB with urban plumes could exacerbate regional ozone (O3) pollution. In the present study, an observational field campaign was performed in a rural area at the northern edge of the Yangtze River Delta region (YRDR) from 15 May to 24 June 2010, during intensive open burning of wheat residues. The net photochemical production rate of oxidant (Ox = O3 + NO2) at the site was evaluated based on a box model (Regional Atmospheric Chemical Mechanism, Version 2) constrained by real-time ambient measurements (e.g., O3, volatile organic compounds (VOCs), NOx (NO2 + NO), J values). Our results showed that both in situ photochemistry and direct transport from urban areas in the YRDR were responsible for the high Ox concentration at the site. During an OBB-impact case, net photochemical production of Ox in the daytime was pronounced, with a 6 h averaged Ox production rate of 13 ± 4 ppbv h-1 (maximum value of 21 ppbv h-1 at 12:00 CST). Photochemical Oxproduction changed from VOC-limited in the morning to NOx-limited in the afternoon due to the rapid photochemical consumption of NOx during the day. A combined analysis with positive matrix factorization demonstrated that O3 pollution in the rural area of the YRDR was largely affected by urban emission, and OBB-related emissions also contributed to in situ photochemical production, particularly in the afternoon. Our study suggested that a joint effort in reducing both NMHCs (e.g., aromatics) and NOx emissions in the urban area, as well as local OBB activities, may be effective in eliminating high-O3 pollution risk in the rural areas of the YRDR.

  15. Calibration of an Energy Water Balance Model Using Satellite Data of Land Surface Temperature for the Upper Yangtze River Basin

    Science.gov (United States)

    Corbari, Chiara, Mancini, Marco; Li, Jiren; Su, Bob

    2013-01-01

    This study has been carried out among the project “Application of remote sensing and other space technology to hydrology and water resources (ID 5281)”. This poster presents a new methodology for the calibration of distributed hydrological models at basin scale by constraining an internal model variable, the pixel-scale equilibrium temperature. Soil hydraulic and vegetation parameters are then calibrated in each pixel of the domain according to the comparison between observed and simulated land surface temperature minimizing the differences. The model algorithm solves the system of energy and mass balances in terms of a representative equilibrium temperature (RET) that is the land surface temperature that closes the energy balance equation and so governs the fluxes of energy and mass over the basin domain. This equilibrium surface temperature, which is a critical model state variable, is comparable to LST as retrieved from operational remote sensing data (MODIS and AATSR). A traditional “trial and error” calibration procedure is also applied by comparing only discharge measurements in the available cross section. The distributed hydrological energy water balance model (FEST-EWB - Flash-flood Event-based Spatially-distributed rainfall-runoff Transformation- Energy Water Balance) has been implemented for the Upper Yangtze River basin with an extent of about 1,000,000 Km2 at spatial resolution of 5km and temporal resolution of 1 hour. Results are provided in terms of hourly evapotranspiration, soil moisture and land surface temperature maps for the period between 2000 to 2004 where ground and satellite data are available for engineering and environmental applications as parsimonious irrigation, real time flood forecast, and quantitative water resources availability. The model accuracy was controlled from the comparison with traditional discharge daily data series and also from the comparison between model and satellite land surface temperature used as a proxy

  16. Measurement and analysis of surface aerosol optical properties over urban Nanjing in the Chinese Yangtze River Delta.

    Science.gov (United States)

    Yu, Xingna; Ma, Jia; Raghavendra Kumar, K; Zhu, Bin; An, Junlin; He, Jiaqi; Li, Mei

    2016-01-15

    Aerosol optical properties including aerosol scattering coefficient (σsp), absorption coefficient (σap), single scattering albedo (SSA), PM2.5 mass concentration and their relationship with meteorological factors were measured and analyzed from 1st March to 30th April 2011. The observations were conducted at an urban-industrial site in Nanjing located in the Yangtze River Delta (YRD) region, China. The averaged σsp at 550 nm is found to be 329.3±321.6 Mm(-1) and occurred most frequently within the range of 100-200 Mm(-1). σap at 532 nm is measured to be 28.1±17.6 Mm(-1), which is remarkably smaller than most of the measurements made over megacities in China and nearly equivalent to the observations made at rural sites in the YRD. The mean SSA at 532 nm is 0.89±0.08 with the occurrence frequency of higher SSA (>0.9) accounting for about 60%, indicating that scattering-related aerosols are dominant over Nanjing during the study period. A bi-peak diurnal variation of σap and σsp is found with the maximum during late at night and early morning and the minimum in the afternoon, but the diurnal pattern of SSA is just the opposite to this. Significant correlation coefficients are noticed between different aerosol optical properties. σsp and σap showed a clear negative correlation with wind speed, temperature, and visibility. During the study period, the lower northwesterly and southeasterly winds are attributed to an increase in the aerosol optical properties. The σsp and σap increased significantly during severe haze and dust episodes caused by the accumulation of pollutants from both local and regional sources under favorable weather conditions. PMID:26519588

  17. Spatio-temporal characteristics of precipitation and dryness/wetness in Yangtze River Delta, eastern China, during 1960-2012

    Science.gov (United States)

    Wang, Yuefeng; Xu, Youpeng; Lei, Chaogui; Li, Guang; Han, Longfei; Song, Song; Yang, Liu; Deng, Xiaojun

    2016-05-01

    Changes in precipitation have a large effect on human society and are a key factor in the study of the patterns of hydrological and meteorological variables. Based on daily precipitation records during 1960-2012 at 24 meteorological stations in the Yangtze River Delta (YRD), the spatial and temporal variations of six extreme precipitation indices were detected by the modified Mann-Kendall test. Then, the characteristics of dryness/wetness patterns were assessed by Standardized Precipitation Index (SPI) and principal component analysis (PCA) on a 24-month time scale. For precipitation extremes, most of the precipitation indices had increasing trends, especially the annual total precipitation in wet day (PRCPTOT), which showed a significant positive trend distributed mainly in the southern part of the YRD. In contrast, decreasing trends in consecutive dry days (CDD) were detected at most stations of the YRD, with more than 20% of the stations having negative trends that were statistically significant. Additionally, three dominant geographic sub-regions of dryness/wetness pattern were identified in YRD: the central and southern, northeastern, and northwestern areas of the YRD. With respect to temporal variations of dryness/wetness conditions in each sub-region, a long-term wet tendency in the central and southern area was characterized as being stronger than the tendency in other parts of the YRD over the past 53 years, which indicates that flood disaster may become increasingly serious in the area. Furthermore, a 4 to 8-year period of variation was observed for each sub-region. The results of this study suggest that adaptive water resource measures for future water resource management and water-related disaster reduction mitigation should be considered separately for these regions in the YRD.

  18. Communities of ammonia oxidizers at different stages of Spartina alterniflora invasion in salt marshes of Yangtze River estuary.

    Science.gov (United States)

    Xia, Fei; Zeleke, Jemaneh; Sheng, Qiang; Wu, Ji-Hua; Quan, Zhe-Xue

    2015-05-01

    Spartina alterniflora, an aggressive invasive plant species at the estuarine wetlands of China's coasts, has become a major threat to the natural ecosystems. To understand its potential influence on nitrification processes, the community structures and abundance of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) were investigated using 454-pyrosequencing and quantitative real-time PCR (qPCR) in S. alterniflora invading salt marsh sediments at the Yangtze River estuary in Chongming island, Shanghai, China. Copy numbers of archaeal and bacterial ammonia monooxygenase subunit A (amoA) genes did not show accordant shifts with S. alterniflora invasion in the two sampling sites. However, the copy numbers of archaeal amoA gene were higher in summer than in spring. Phylogenetic analysis indicated that more than 90% of the archaeal and 92% of the bacterial amoA gene sequences were closely related to marine group I.1a and the clusters 13 and 15 in Nitrosospira lineage, respectively. The effect of different seasons (spring and summer) was important for the abundance variation of AOA, while different stages of S. alterniflora invasion did not show significant effect for both AOA and AOB. Variation of AOA community was significantly related to total carbon (TC) and sulfate concentration (P < 0.05), whereas the AOB community was significantly related to sulfate concentration, total nitrogen (TN), TC and pH (P < 0.05). In conclusion, the abundance and diversity of ammonia oxidizing microbial communities were not strongly affected by S. alterniflora invasion. PMID:25935302

  19. Trend of dissolved inorganic nitrogen at stations downstream from the Three-Gorges Dam of Yangtze River

    International Nuclear Information System (INIS)

    The TRAMO/SEATS program, combined with the Hodrick–Prescott (HP) filter, was used to detect trends and potential change points in time series of dissolved inorganic nitrogen (DIN) at three stations along the Yangtze River. The trend components were extracted, and two change points were successfully detected. The components revealed that DIN has been increasing at all the stations since the 1990s, although variations exist. Changes visible before 2002 illustrate the differences in agriculture development among regions upstream from the stations. The Three-Gorges Dam (TGD), which began to impound in 2003, led to years of different trends. The DIN concentration, which had been trending upward prior to that date, began a slightly downward trend because of NH4+ depletion. Readings at the Yichang station revealed this trend most strongly; those at the Hankou station less so. The Datong station was far enough away from the TGD so that no obvious effects were seen. -- Highlights: •TRAMO/SEATS program coupled with HP filter was used to find water quality trends. •Smooth trends other than step trends were separated from trend-cycle components. •DIN concentration was proved to be a reflection of agricultural development. •The three stations experienced different agricultural development since 1990s. •The impoundment of the Three-Gorges Dam can impact as far as to the Hankou station. -- DIN concentrations were reflections of agricultural development in the YRB, but the impoundment of TGD since June, 2003 also had impacts on DIN concentrations far to the Hankou station

  20. Retrieval of tropospheric NO2 vertical column densities and aerosol optical properties form MAXDOAS measurements in Yangtze River Delta, China

    Science.gov (United States)

    Hao, Nan; Van. Roozendael, Michel; Ding, Aijun; Zhou, Bin; Hendrick, François; Shen, Yicheng; Wang, Tin; Valks, Pieter

    2014-05-01

    Air pollution is one of the most important environmental problems in developing Asian countries like China. Due to huge consumption of fossil fuels and rapid increase of traffic emissions in the past decades, many regions in China have been experiencing heavy air pollution. The Yangtze River Delta (YRD) region includes the mega-city Shanghai and the well-industrialized and urbanized areas of Zhejiang Province and Jiangsu Province, with over ten large cities, such as Hangzhou, Suzhou and Nanjing. Covering only 2% land area, this region produces over 20% of China's Gross Domestic Product (GDP) which makes it the most densely populated region and one of the most polluted regions in China. For instance, there more than 60% of a year was haze days with poor visibility in Shanghai over the last few years. In the YRD region, knowledge gaps still exist in the understanding of the source and transport of air pollutants because only few measurement studies have been conducted. MAX-DOAS measurements were performed in Shanghai city center and Wujiang (border of Shanghai and Jiangsu Province) from 2010 to 2012 and in Nanjing (capital of Jiangsu Province) from April 2013. A retrieval algorithm, based on an on-line implementation of the radiative transfer code LIDORT and the optimal estimation technique, has been used to provide information on aerosol extinction vertical profiles. The total aerosol optical depths (AODs) calculated from the retrieved profiles were compared to MODIS, AERONET and local PM measurements. The aerosol information was input to LIDORT to calculate NO2 air mass factors. The retrieved tropospheric NO2 vertical column densities (VCDs) were compared to in-situ and satellite NO2 measurements.

  1. Emission inventory of primary pollutants and chemical speciation in 2010 for the Yangtze River Delta region, China

    Science.gov (United States)

    Fu, Xiao; Wang, Shuxiao; Zhao, Bin; Xing, Jia; Cheng, Zhen; Liu, Huan; Hao, Jiming

    2013-05-01

    We developed a high-resolution emission inventory of primary air pollutants for Yangtze River Delta (YRD) region, which included Shanghai plus 24 cities in the provinces of Jiangsu and Zhejiang. The emissions of SO2, NOX, PM10, PM2.5, NMVOCs and NH3 in the year of 2010 were estimated as 2147 kt, 2776 kt, 1006 kt, 643 kt, 3822 kt and 1439 kt, respectively. Power plants are the largest emission sources for SO2 and NOX, which contributes 44.1% and 37.3% of total SO2 and NOX emissions. Emissions from industrial process accounted for 26.9%, 28.9% and 33.7% of the total PM10, PM2.5 and NMVOCs respectively. Besides, 37.3% of NMVOCs emissions were contributed by solvent use. Livestock and fertilizer application contribute over 90% of NH3 emissions. High emission densities are visible in Shanghai and the area around Tai Lake. This emission inventory includes the speciation of PM2.5 for the YRD region for the first time, which is important to source apportionment and secondary-pollution analysis. In 2010, emissions of three major PM2.5 species, namely OC, EC and sulfate, are 136.9 kt, 75.0 kt and 76.2 kt, respectively. Aromatics and alkanes are the main NMVOC species, accounting for 30.4% and 20.3% of total VOCs. Non-road transportation and biomass burning were main uncertain sources because of a lack of proper activity and emission factor data. Compared with other pollutants, NMVOCs and NH3 have higher uncertainty. From 2000 to 2010, emissions of all pollutants have changed significantly, suggesting that the newly updated and high-resolution emission inventory will be useful for the identification of air pollution sources in YRD.

  2. An integrated process rate analysis of a regional fine particulate matter episode over Yangtze River Delta in 2010

    Science.gov (United States)

    Li, L.; Huang, C.; Huang, H. Y.; Wang, Y. J.; Yan, R. S.; Zhang, G. F.; Zhou, M.; Lou, S. R.; Tao, S. K.; Wang, H. L.; Qiao, L. P.; Chen, C. H.; Streets, D. G.; Fu, J. S.

    2014-07-01

    A high PM2.5 pollution episode was detected in Shanghai in November 2010. The integrated process rate method, an advanced diagnostic tool, was applied to account for the contribution of different atmospheric processes during the high pollution episode in the Yangtze River Delta region (YRD). The PM2.5 process analysis indicates that the emission of fine particles is the dominant source of high surface PM2.5 concentrations in the major cities of the YRD like Shanghai, Nanjing, and Hangzhou, following horizontal transportation and aerosols. The PM2.5 concentration could be reduced due to vertical advection and diffusion from lower levels to the upper air. The aerosols process such as homogeneous nucleation and condensation producing PM2.5 occurs throughout the PBL layer in urban areas, causing vertical transport from upper levels down to the surface layer. The aerosols process is much more significant in a downwind rural and coastal site like Zhoushan than in the urban areas. The PM2.5 change initiated by both horizontal transport and vertical transport is much stronger at 40-2000 m height than in the surface layer, while the PM2.5 change caused by horizontal diffusion is very small. Dry deposition can significantly reduce concentration of the particulates in the surface level of the atmosphere, and wet deposition can remove the particles in the planetary boundary layer (PBL). The cloud processes can either increase PM2.5 due to the aqueous-phase oxidation of SO2 and NO2 or remove PM2.5 due to cloud scavenging. Solar radiation and humidity are more important to secondary pollution, and they are the significant external factors affecting the chemical reactions among sulfur dioxide, nitrogen oxides, ammonia, volatile compounds and fine particles.

  3. Effects of elevated O3 concentration on winter wheat and rice yields in the Yangtze River Delta, China

    International Nuclear Information System (INIS)

    The effects of a continuing rise of ambient ozone on crop yield will seriously threaten food security in China. In the Yangtze River Delta, a rapidly developing and seriously air polluted region in China, innovative open-top chambers have been established to fumigate winter wheat and rice in situ with elevated O3. Five years of study have shown that the yields of wheat and rice decreased with increasing O3 concentration. There were significant relationships between the relative yield and AOT40 (accumulated hourly O3 concentration over 40 ppb) for both winter wheat and rice. Winter wheat was more sensitive to O3 than rice. O3-induced yield declines were attributed primarily to 1000-grain weight and harvest index for winter wheat, and attributed primarily to grain number per panicle and harvest index for rice. Control of ambient O3 pollution and breeding of O3 tolerant crops are urgent to guarantee food security in China. - Highlights: ► The wheat and rice response to ozone had been investigated for five years in China. ► There were significant relationships between relative crop yields and AOT40 dose. ► O3-induced wheat yield loss was primarily due to 1000-grain weight and harvest index. ► O3-induced rice yield loss was primarily due to grains per panicle and harvest index. ► Wheat and rice in this study are more sensitive to O3 than previous investigations. - The dose–response relationships derived from field fumigation experiments over 5 years can be used to accurately estimate crop losses in China.

  4. Impact of biomass burning on haze pollution in the Yangtze River delta, China: a case study in summer 2011

    Science.gov (United States)

    Cheng, Z.; Wang, S.; Fu, X.; Watson, J. G.; Jiang, J.; Fu, Q.; Chen, C.; Xu, B.; Yu, J.; Chow, J. C.; Hao, J.

    2014-05-01

    Open biomass burning is an important source of air pollution in China and globally. Joint observations of air pollution were conducted in five cities (Shanghai, Hangzhou, Ningbo, Suzhou and Nanjing) of the Yangtze River delta, and a heavy haze episode with visibility 2.9-9.8 km was observed from 28 May to 6 June 2011. The contribution of biomass burning was quantified using both ambient monitoring data and the WRF/CMAQ (Weather Research and Forecasting (WRF) and Community Multiscale Air Quality (CMAQ)) model simulation. It was found that the average and maximum daily PM2.5 concentrations during the episode were 82 and 144 μgm-3, respectively. Weather pattern analysis indicated that stagnation enhanced the accumulation of air pollutants, while the following precipitation event scavenged the pollution. Mixing depth during the stagnant period was 240-399 m. Estimation based on observation data and CMAQ model simulation indicated that biomass open burning contributed 37% of PM2.5, 70% of organic carbon and 61% of elemental carbon. Satellite-detected fire spots, back-trajectory analysis and air quality model simulation were integrated to identify the locations where the biomass was burned and the pollutants transport. The results suggested that the impact of biomass open burning is regional, due to the substantial inter-province transport of air pollutants. PM2.5 exposure level could be reduced 47% for the YRD region if complete biomass burning is forbidden and significant health benefit is expected. These findings could improve the understanding of heavy haze pollution, and suggest the need to ban open biomass burning during post-harvest seasons.

  5. Evaluation on the High Yielding, Stability and Comprehensive Performances of Check Cultivars in National Cotton Regional Trials in the Yangtze River Valley

    Institute of Scientific and Technical Information of China (English)

    Shiqiao JIN; Naiyin XU

    2014-01-01

    Objective] This study was to analyze the high yielding, stability, adaptabil-ity and main characteristics of check cultivars in national cotton regional trials in the Yangtze River Val ey in 2000-2013, with the aim to provide theoretical basis for the reasonable selection of check cultivars for cotton regional trials. [Method] GGE biplot analysis method was used to carry out the intensive analysis and comprehensive comparisons on the performances and differences of the 9 major characters of check cultivars, namely, lint cotton yield , stability, and other main traits including bol weight, bol number, lint percentage, fiber length, fiber strength, micronaire val-ue, plant height and seed index. [Result] Ezamian 10 was suitable in the majority of cotton planting regions in the Yangtze River Val ey, with the best high yielding abili-ty and perfect yield stability. The yielding ability of Xiangzamian 8 ranked the sec-ond, but its stability was the poorest. Xiangzamian 8 was of the specific adaptive cultivar with relatively good performance in high yielding but the poorest stability. The suitable planting areas of Xiangzamian 8 were limited to the cotton planting re-gion around Dongting Lake in Hunan province, Poyang Lake in Jiangxi Province, the Coastal region in Jiangsu Province and Wuhan district in Hubei Province. Xi-angzamian 2 performanced poorer in both yielding and stability, while Simian 3 ranked first in stability but the last in yielding ability. The dominant character of Xi-angzamian 8 and Xiangzamian 2 were high cotton plants and big bol s. Simian 3 performanced super in lint percentage and fiber length. Ezamian 10 was strong in cotton bol formation ability, lint cotton yielding, fiber strength and seed size, as wel as high micronaire value. [Conclusion] The outstanding performance of Ezamian 10 in high and stable yield in the Yangtze River Val ey in recent years has effectively promoted the high yielding ability of candidate varieties in cotton regional

  6. Evolution of Nitrogen, Phosphorus and Potassium Fertilizer Application Rates in Cotton Fields and lts lnfluences on Cotton Yield in the Yangtze River Valley

    Institute of Scientific and Technical Information of China (English)

    Naiyin XU; Jian Ll

    2014-01-01

    Objective] The historical evolution pattern of nitrogen (N), phosphorus (P) and potassium (K) fertilizer application rate and its effects on lint cotton yield were explored to provide the theoretical basis for reasonable fertilizer management strate-gy in the cotton planting region of the Yangtze River Val ey. [Method] GGE biplot analysis method was adopted to analyze the correlation among N, P and K fertilizer application rate and lint cotton yield with the dataset of national cotton regional trials of the Yangtze River Val ey during 1991-2013. The linear and nonlinear regression analysis method was used to reveal the evolution of the fertilizer applying patterns, and analyze the effects of N, P, K application rates on cotton lint yield. [Result] The application rates of N, P and K fertilizer presented highly significant positive corre-lation with lint cotton yield, among which the potassium fertilizer was the strongest relative factor with lint cotton yield, fol owed by phosphorus fertilizer, while nitrogen fertilizer was the weakest factor. The application rate of nitrogen fertilizer was relat-ed with the test year in the pattern of a quadratic function, while phosphate and potassium had progressive increase linear relation with the test year in the cotton planting region of the Yangtze River Val ey. Meanwhile, cotton lint yield was in re-sponse to nitrogen fertilizer content increase with a quadratic parabola function, and increased with the applying phosphate fertilizer and potassium fertilizer content with linearly increasing function. [Conclusion] The increasing application amount of N, P and K fertilizer was general y beneficial to cotton yield improvements, however, ex-orbitant applying nitrogen fertilizer was unfavorable for cotton production, and a reasonable mixture formula of N, P and K fertilizer was better in terms of cotton yield-increasing effect.

  7. 《人民长江》文献计量学统计分析%Bibliometric analysis of Journal of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    刘棣辉

    2014-01-01

    In order to analyze the characteristics of published articles in the Journal of Yangtze River and its development trend, 674 published articles in the Journal of Yangtze River during 2013 were studied in the aspects of published articles, re-search sponsorship, authors and references, using bibliometrics, and the results were compared with the relative data in 2012. It shows that the basic indexes of Journal of Yangtze River reached or surpassed the standard of national excellent journals;the arti-cles published can represent the advanced hydraulic science and technology and its development trend; the academic quality of the articles were improving, which would provide more fresh and feasible scientific information for researchers.%为了分析水利科技期刊《人民长江》杂志载文特点和今后发展趋势,运用出版计量学的方法,对该杂志2013年(1~24期)所刊载的674篇学术论文从载文、基金资助、作者与引文等方面进行了定量研究,并与该刊2012年的有关统计数据进行对比。分析结果表明,《人民长江》基本指标均达到或超过国家优秀期刊标准,刊载的论文代表着相关学科的前沿和发展方向;载文学术质量水平正在不断提升,将为水利研究工作者提供更多、更新、更适用的科研信息。

  8. The Evolvement and Driving Mechanism of Economic Network Structure in the Changjiang River Economic Zone%长江经济带经济网络结构演变及其驱动机制研究

    Institute of Scientific and Technical Information of China (English)

    钟业喜; 冯兴华; 玉钊

    2016-01-01

    在构建城市间经济联系网络基础上,从网络密度、中心性、核心-边缘结构、QAP分析等角度对1988~2012年长江经济带经济网络结构演变及其驱动机制进行深入分析。结果表明:长江经济带经济联系网络结构日趋成熟,三大经济地带内城市内聚性显著增强但地带间差异逐渐缩小,经济网络向均衡化发展;城市度中心性整体持续下降,经济网络出现多核心趋势,城市介中心性高值区的梯度推移特征明显;“核心-边缘”结构分析显示核心度高值区呈片状格局,高核心度城市由“质大量少”向“质小量多”转变,经济网络的“核心-边缘”结构呈组团式发展,组团内形成各自核心城市;QAP分析显示经济全球化、要素集聚与扩散、产业升级、交通技术创新与城市群建设等机制共同驱动着长江经济带经济联系网络的演变及优化重组。%The Changjiang River Economic Zone is the second largest economy belt, followed Chinese coastal economic regions, which has the most competitive and the great development potential. The development of Changjiang River Economic Zone plays the important exemplary role and is strategically significant for region-al harmonious development, new urbanization construction and ecological civilization construction in China. The analysis on the economic network evolution of the Changjiang River Economic Zone can effectively grasp the stage of regional development and make up urban and regional developmental strategy. With the aid of UCINET and ArcGIS, this article analyzed the evolution of economic network and its driving mechanism from density, centralization,“core-edge”structure and QAP (Quadratic Assignment Procedure) analysis based on economic construction data of city during 1988-2012. The result shows that:economic contacts’network struc-ture tends to be mature, cities’inner cohesion enhances in three sub

  9. Economic development trends in Yangtze River Delta%长三角区域经济发展显现几大态势

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Stimulated by the duel role of the State macroeconomic control and market regulation, there are signs of appropriate readjustment of economic development in the Yangtze River delta area in east China. The readjustment has helped check the rise of some unhealthy and uncertain factors in local economic growth, relax the tense supply of energy and slow down economic growth. While making a remarkable drop in the growth of fixed asset investment, the area has seen a brisk increase in sales on the consumer market. The role of investment, consumption and export in regional economic development has become more rational. The area has demonstrated the following features:

  10. Research Note:Effects of human activities on the Yangtze River suspended sediment flux into the estuary in the last century

    OpenAIRE

    Yang, S.L.; Shi, Z; H. Y. Zhao; Li, P.; Dai, S. B.; Gao, A.

    2002-01-01

    The surface erosion area in the Yangtze River basin increased from 364×103 km2 in the 1950s to 707×103 km2 in 2001 due to a great increase in population. Based on the regression relationship between surface erosion area and population, the surface erosion area was predicted to be about 280×103 km2 at the beginning of the 20th century. The sediment yield, which increased by about 30% during the first six decades of the 20th century, was closely related to the surface erosion area i...

  11. Temporal-Spatial Evolution Analysis of Lake Size-Distribution in the Middle and Lower Yangtze River Basin Using Landsat Imagery Data

    OpenAIRE

    Lin Li; Hui Xia; Zheng Li; Zhijun Zhang

    2015-01-01

    Four natural lakes in the middle and lower reaches of the Yangtze River—Dongting Lake, Poyang Lake, Chaohu Lake and Taihu Lake—play a key role in the climate, environment, and ecology of this area. Upstream of these lakes, the Three Gorges Dam Project has been storing water for 12 years. Future monitoring and management of rivers and lakes can certainly benefit from research on the patterns of variation of natural lakes downstream of the Three Gorges Project. This research applies Landsat TM...

  12. Challenge and Perspective of Yangtze River Basin Water Resources Protection%长江水资源保护面临的挑战与前景

    Institute of Scientific and Technical Information of China (English)

    袁弘任

    2002-01-01

    The major faced problems at present in Yangtze river basin are: ① uneffective control in river water pollution threatens seriously the safety of drinking water; ② shrinkage of lake area and serious eutrophication; ③ soil-water losses degraded the ecological environment of the basin; ④ the impact of TGP and S-N water transfer project on water environment of the basin. In the light of above-mentioned problems, water resources utilization strategy must be adjusted and the sustainable social and economic development should be supported by sustainable water resources utilization, and it is necessary to take the following countermeasures: ① establishing overall flood control and disaster relief system; ② developing high water use efficiency agriculture; ③ taking "giving priority to water saving on the basis of pollution control" as urban water resources utilization strategy; ④ implementing comprehensive pollution control strategy with sources control as main point; ⑤ guaranteing water demand of the ecological environment; ⑥implementing the strategy of maintaining water resources supply and demand balance on the basis of water demand management; ⑦ studying countermeasures for the ecological and environmental impacts of trans-basin water transfer and western China devolopment. The key of realization of sustainable water resources utilization is to reform management and investment mechanism of water resources and water price policy. It is the only way to solve the water resources problems in Yangtze river basin as well as the whole China.

  13. General Construction Scheme for Anqing Changjiang River Railway Bridge%安庆长江铁路大桥总体施工方案

    Institute of Scientific and Technical Information of China (English)

    农代培; 季跃华; 徐炳法

    2013-01-01

    安庆长江铁路大桥采用双塔三索面钢桁梁斜拉桥和6孔64 m跨现浇简支箱梁布置形式,铁路4线.深水区3号、4号桥塔墩采用先围堰后平台的双壁钢围堰施工方案;5号墩桩基采用定位桩平台施工方案,承台采用双壁钢围堰施工方案.浅水区6号、7号及W01号、W02号桥墩桩基采用双栈桥加定位桩平台施工方案,承台采用钢板桩围堰施工方案.桥塔起始段采用支架法施工,其余采用大节段液压爬模施工;横梁采用支架法施工,分2层浇注.主桥无索区钢梁采用膺架法架设,桥塔墩有索区钢梁采用架梁吊机对称伸臂架设;在3号墩设置桁内开启式提升站取梁;全桥设2个合龙口,先中跨、后边跨合龙.非通航孔桥64 m箱梁采用支架法现浇施工.水中墩平台、围堰及栈桥考虑不同设防水位.该桥已于2012年12月实现多点精确合龙.%Anqing Changjiang River Railway Bridge was arranged as a 4-track railway steel truss girder cable-stayed bridge with double pylons,triple cable planes and with 6 spans of 64-m cast-in-situ simply-supported box girders.The pylon piers No.3 and No.4 of the bridge in the deep water area were constructed by the scheme of double-wall steel cofferdams,in which the cofferdams were set up first and the working platforms were late.The pile foundation of the pier No.5 was constructed by the positioning pile platform and the pile cap of the pier was constructed by the double-wall steel cofferdam.The pile foundations of the piers No.6,No.7 and the piers W01 and W02 in the shallow water area were constructed by the twin trestle bridges and positioning pile platforms and the pile caps thereof were constructed by the steel sheet pile cofferdams.The starting segments of a pylon were constructed by the scaffolding method while the rest of the segments were constructed by the large segment hydraulic climbing formwork.The cross beam of the pylon was cast in two layers by the scaffolding method

  14. Making greater accomplishment in creating beautiful Yangtze River by seizing opportunities and meeting challenges%抓住机遇迎接挑战为保护美丽长江再谱新篇

    Institute of Scientific and Technical Information of China (English)

    王方清

    2015-01-01

    At present, the water resources protection of Yangtze River is facing a unique opportunity, how to promote the water ecological civilization construction of Yangtze River and create an ecological corridor with clear water, green land and blue sky is an important issue. Through summarizing the problems in water resources protection of Yangtze River, the general protection idea in future period is planned;the main tasks in the next stage are discussed from 5 aspects of planning system, water function zone supervision, water ecological protection, emergent management and monitoring-controlling;the protection measures for the main stream of Yangtze River, Three Gorges Reservoir, Danjiangkou Reservoir and the estuary of Yangtze River as well as the main lakes in the Yangtze River Basin are put forward;through constructing sound laws and regulations system, innovating management system, strengthening capability construction, the capability of Yangtze River water resources protection would be improved and the water resources management system would be perfected, so as to make greater accomplishment in creating beautiful Yangtze River.%当前长江流域水资源保护面临难得的机遇,如何推进长江水生态文明建设,打造水清地绿天蓝的生态廊道是长江水资源保护工作的重大课题。通过对长江水资源保护问题的梳理,规划了今后一段时期的总体构想,从规划体系、水功能区监管、水生态保护、应急管理和监测监控等5个方面探讨了下一步的工作重点;提出了长江干流、主要支流、三峡、丹江口和长江口以及重点湖泊的保护措施;通过健全法规体系、创新管理机制、强化能力建设等,以逐步提升长江水资源保护能力、健全长江水资源保护管理体系,为保护美丽长江再谱新篇。

  15. Rock magnetism on fluvial sediments of Lower Yangtze River, relations to pedogenesis and climate changes of the last 150 years

    Science.gov (United States)

    Zheng, Y.; Yang, S.; Deng, C.

    2012-12-01

    Fluvial sediment is one of the most important records for climate change of the river drainage area. While the fluvial sediment experience chemical reaction downward, the profile would show similar layer changes like soil profile, but also presents some different features, such as without parent rock and the weak weathering layer above rock. Therefore, the fluvial sediment profile could not only investigate the climate changes, but also study the features of pedogenesis. Magnetic method has been applied in soil investigation, which is very sensitive to the chemical changes on soil profile for iron ion. In order to understand the magnetic mineral and chemical changes along the profile, detailed magnetic measurements were carried out on a 2 m fluvial sediment profile of Lei Gong Zui (LGZ) Island, which is one of small islands in the middle of lower Yangtze River in Yangzhou City (32°18.4‧N, 119°45.2‧E). This profile spans the last 150 years by Pb210 dating, with average sedimentation rate of 1.3 mm/yr. Rock magnetic measurements, such as thermal magnetic (low temperature and high temperature) and magnetic hysteresis measurements, show that dominant magnetic minerals of the profile are magnetite, hematite and goethite. Variations of relative concentration of each mineral indicate climate changes and also soil chemical reaction. For the top 0.8 m, magnetic concentration presents a downward decline, which is mostly due to soil leaching processes, with dissolution of iron minerals into iron ion. At about 0.8 m, a belt with high concentration of hematite is observed, which is an important signal for illuviation belt. Below 0.8 m, fluctuation of magnetic properties can be well compared to variation of summer Asian Monsoon (AM) during the last 150 years, during which low magnetic concentration corresponds to weak summer AM. This result proves that magnetic analysis on fluvial sediment is a useful way to investigate climate change in the last hundred years. Separation

  16. Communities of gastrointestinal helminths of fish in historically connected habitats: habitat fragmentation effect in a carnivorous catfish Pelteobagrus fulvidraco from seven lakes in flood plain of the Yangtze River, China

    OpenAIRE

    Yao Wei J; Wang Gui T; Nie Pin; Li Wen X

    2009-01-01

    Abstract Background Habitat fragmentation may result in the reduction of diversity of parasite communities by affecting population size and dispersal pattern of species. In the flood plain of the Yangtze River in China, many lakes, which were once connected with the river, have become isolated since the 1950s from the river by the construction of dams and sluices, with many larger lakes subdivided into smaller ones by road embankments. These artificial barriers have inevitably obstructed the ...

  17. Multi-scale hydrologic applications of the latest satellite precipitation products in the Yangtze River basin using a distributed hydrological model

    Science.gov (United States)

    Li, Zhe; Yang, Dawen; Gao, Bing; Jiao, Yang; Hong, Yang; Xu, Tao

    2015-04-01

    The current era of satellite remote sensing has provided unprecedented opportunities for the monitoring and prediction of Earth's terrestrial hydrologic cycle. In the present study, we evaluated three global satellite precipitation products (3B42 V7, 3B42 RT and CMORPH) during 2003-2012 for multi-scale hydrological applications, including annual water budgeting, monthly and daily streamflow simulation, and extreme floods modeling, via a distributed hydrological model (GBHM) in the Yangtze River basin. This regional evaluation is first performed at temporal scales ranging from annual to daily, based on a number of diagnostic statistics, providing useful information on the error characteristics associated with the three satellite precipitation products. Then the work, with an application-oriented view, focuses on the modeling-based evaluation of the three products. The results show 3B42 V7 data generally has a better performance in annual water budgeting and monthly streamflow simulation, but this superiority is not guaranteed for daily simulation, especially for floods monitoring. It is also found that, for annual water budgeting, the positive (negative) bias of 3B42 RT (CMORPH) estimates have been mainly propagated into the simulated runoff, while the simulated evapotranspiration tends to be more sensitive to negative bias. Regarding streamflow simulation, both near-real-time products show region-dependent bias: 3B42 RT tends to overestimate streamflow in the upper Yangtze River; in contrast, CMORPH shows serious underestimation in those downstream sub-basins, while it is able to effectively monitor streamflow into the Three Gorges Reservoir. With 394 selected flood events, the results indicate that 3B42 RT and CMORPH have competitive performances for near real-time floods monitoring in the upper Yangtze, but for those downstream sub-basins, 3B42 RT performs better than CMORPH. Furthermore, the inability of all satellite products to capture some key features of the

  18. “新常态”下长江经济带发展略论--“长江经济带高峰论坛”主旨演讲摘要%Brief Review on the Development of Yangtze River Economic Zones Under the “New Normal” Background-Abstract of Keynote Speech in Yangtze River Economic Zones Summit

    Institute of Scientific and Technical Information of China (English)

    西部论坛

    2015-01-01

    2014年9月12日国务院发布了《国务院关于依托黄金水道推动长江经济带发展的指导意见》;12月中央经济工作会议指出,要继续实施西部开发、东北振兴、中部崛起、东部率先的区域发展总体战略,重点实施“一带一路”、京津冀协同发展、长江经济带三大战略。虽然自20世纪80年代以来,已多次提出过长江流域经济发展的区域战略和措施,但在中国经济“新常态”下的长江经济带发展,需要新理念、新思路、新举措。为推动长江经济带研究进一步全面、深入展开,并为推进长江经济带发展献计献策,2014年11月29日,由中国区域经济学会、重庆工商大学主办的“长江经济带高峰论坛”在重庆举办,来自北京、天津、上海等12个省市30多名领导、专家共同出席研讨长江经济带建设与发展。本刊将本次论坛上20位专家所作主旨演讲的主要内容摘录如下①,以飨读者。%Editor’ s Note:Guidance to Promote the Development of the Yangtze River Economic Zones Relying on the Gold Waterway by the State Council was issued on Sept. 12, 2014. The Central Economic Working Conference in December indicated that the overall strategy of Western Development, Northeast Revitalization, Central Rise and Eastern Leading should be continued implemented, and focus on the implementation of Three Strategies, i.e. “One Belt and One Road” Project, the Coordinated Development of Beijing⁃Tianjin⁃Hebei and Yangtze River Economic Zones Development. Although regional strategy and measures of Yangtze River economic zones development have been proposed since 1980s of 20th century, new concept, new mindset and new measure should be put forward for Yangtze River economic zones development under the “New Normal” background. In order to research Yangtze River Economic Zones in⁃depth and in⁃width, and to contribute ideas and exert efforts for Yangtze River

  19. Demonstration of Bridge Type Schemes for Maanshan Changjiang River Bridge Under Condition of Complicated River Pattern%复杂河势条件下的马鞍山长江大桥桥型方案论证

    Institute of Scientific and Technical Information of China (English)

    杨光武

    2013-01-01

    马鞍山长江公路大桥所处河段为分汊河段,其中左汊主桥桥址处河势条件复杂,通过对桥址处河势条件及通航要求等建桥条件的综合分析,对5种左汊主桥桥型方案(主跨2×1080m三塔悬索桥方案、主跨1 388 m两塔悬索桥方案、主跨1 180m两塔斜拉桥方案、主跨2×850m三塔斜拉桥方案、主跨1 760m单跨悬索桥方案)从航道适应性、工程经济性进行比较和论证.经过综合比选,确定马鞍山长江公路大桥左汊主桥采用主跨2×1 080 m三塔两跨悬索桥,较好地解决了深槽左右摆动引起的航道适应性问题,为大桥的顺利立项和获批创造了有利条件.%The river reaches at the site of Maanshan Changjiang River Highway Bridge are the forked reaches, of which the condition of river pattern of the reach at the site of the main bridge of the left bridge is quite complicated. Through the comprehensive analysis of the construction conditions, such as the river pattern and navigation requirements, of the site of the main bridge, five bridge type schemes (i. e. a three-tower suspension bridge with main spans 2×1 080 m, a two-tower suspension bridge with a main span 1 388 m, a two-pylon cable-stayed bridge with a main span 1 180 m, a three-pylon cable-stayed bridge with main spans 2×850 m and a single-span suspension bridge with a main span 1 760 m) put forward for the bridge were compared and demonstrated from aspects of the waterway adaptability and engineering economy. On the basis of the comparison and demonstration, it was finally determined that the scheme of the three-tower and two-span suspension bridge with main spans 2×1080 m should be chosen for the bridge. With the chosen scheme, the problem of the waterway adaptability affected by the left and right swaying of the deep channel was well resolved and the favorable conditions for the successful determining and approval of the bridge project were thus created.

  20. Engineering Geological Study of the Active Tectonic Region for Hydropower Development on the Jinsha River, Upstream of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The Jinsha River runs across the Hengduanshan north-south tectonic zone where neotectonism was relatively strong, accompanied by various geologic hazards. In this case, it seems necessary to make a quantitative assessment and grading of the engineering geological environment for the planning and development of hydropower projects on the Jinsha River.The studies of crustal structures and activities of neotectonic fault blocks provide a three-dimensional geomechanics model for us to make an assessment of the engineering geological environment. Based on the survey data and results from geologic hazard risk analysis, a hierarchical analysis model on the quality of the engineering geological environment is established with respect to the crustal stability, ground stability, and rock and soil mass stability. Nine factors relevant to the geological environment are selected and five levels are used for the quality grades: very bad, bad, mediocre, good, very good. The result indicates that active deep faults have an influence on the engineering geological environment of the Jinshajiang region.Finally, the authors present a preliminary evaluation on the constructional suitability of each planned site in the middle and lower reaches of the Jinsha River.

  1. SEDIMENT RESEARCH FOR THE THREE GORGES PROJECT ON THE YANGTZE RIVER SINCE 1993

    Institute of Scientific and Technical Information of China (English)

    Bingnan LIN; Ren ZHANG; Dingzhong DAI; Ying TAN

    2005-01-01

    This article addresses sediment research carried out for the Three Gorges Project since 1993,when the construction of the project was formally started. Emphasis of the research has been placed on the solution of relevant problems arising from design and construction of various structures,including sedimentation problems in the Chongqing reach; layout of the upper lock approach channel and ways and means to mitigate its deposition; increasing reservoir capacity by optimizing reservoir operation; compensating depth of flow required by navigation below the Gezhouba Project caused by scouring; mitigation of adverse effects of erosion on the reach from Zhicheng to Jiangkou; and evaluating scour of the Jinjiang reach caused by releasing flows of low concentrations from the TGP. In addition,reduction of the sediment load entering into the reservoir area of the TGP in the recent years as well as that expected of the projected construction of large hydropower stations on the Jinsha River upstream of the TGP reservoir is also noted and discussed.

  2. CLASSIFICATION AND TYPES OF PREFERENTIAL FLOW FOR A DARK CONIFEROUS FOREST ECOSYSTEM IN THE UPPER REACH AREA OF THE YANGTZE RIVER

    Institute of Scientific and Technical Information of China (English)

    Jianzhi NIU; Xinxiao YU; Zhiqiang ZHANG; Yutao ZHAO

    2007-01-01

    Preferential flow is the ordinary phenomenon of rapid and non-equilibrium transport of water and solutes occurring in most soil. It causes latent pollution of ground and surface waters and affects runoff yield and flow concentration. This paper studies preferential flow for a dark coniferous ecosystem in the upper reach area of the Yangtze River, establishes a classification for the preferential flow and discusses types of preferential flow with a soil column experiment using a homemade apparatus and dye-tracer analysis. The preferential flow is mainly unsaturated gravitational flow in the upper layer of the slope deposit for mature forest soil, which is dominated by a wetness front, and the flow gradually transforms to macroporous flow as the soil layer deepens. The observed preferential flow in the young, middle-aged and over-mature forests that have grown on glacial lateral moraines is macroporous flow. The purpose of this research is to analyze systemically the behavior of soil water movement for a dark coniferous forest ecosystem in the upper reach area of the Yangtze River and to provide a theoretical basis for effective watershed management.

  3. Estimates of long-term water total phosphorus (TP) concentrations in three large shallow lakes in the Yangtze River basin, China.

    Science.gov (United States)

    Wu, Pan; Qin, Boqiang; Yu, Ge

    2016-03-01

    The shallow lakes in the eastern China developed on alluvial plains with high-nutrient sediments, and most overflow into the Yangtze River with short hydraulic residence times, whereas they become eutrophic over long time periods. Assuming strong responses to hydrogeological changes in the basin, we attempted to determine the dynamic eutrophication history of these lakes. Although evaluation models for internal total phosphorus (TP) loading are widely used for deep lakes in Europe and North America, the accuracy of these models for shallow lakes that have smaller water volumes controlled by the geometrical morphology and greater basin area of alluvial plains is unknown. To describe the magnitude of changes in velocity of trophic state for the studied shallow lakes, we first evaluated the P retention model in relation to the major forces driving lake morphology, basin climate, and external discharge and then used the model to estimate changes in TP in three large shallow lakes (Taihu, Chao, and Poyang) over 60 years (1950-2009 AD). The observed levels of TP were verified against the relative error of the three lakes (lakes Taihu and Poyang became eutrophic in the 1990s, whereas Lake Chao became eutrophic in the 1980s; lakes Taihu and Chao ultimately became hypereutrophic in the 2000s. The analysis suggested that the tropic status of the shallow lakes was affected by both the hydroclimate and geological sedimentation of the Yangtze River basin. This work will contribute to the development of an internal P loading model for further evaluating trophic states. PMID:26549710

  4. 长江南通段半潜船作业风险分析%Risk Analysis of Semi-submersible Operations in Nantong Section of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    吴志刚; 刘小芳

    2012-01-01

      In recent years, the semi-submersible vessels operating frequency in Nantong Section Water Area of Yangtze River is showing an increasing trend. The semi-submersible vessels operating have high Technical content, many factors affect the safety of operations, such as environmental factors, human factors, during the operation, the risk is greater. This article will combine the characteristics of the Nantong Section Water Area of Yangtze River to analysis of the risk in the semi-submersible vessels operations.%  近年来,长江南通段半潜船作业频次呈现出递增趋势。半潜船作业技术含量高,影响作业安全的因素较多,如环境因素、人为因素等,作业过程中的风险性较大。文中将结合长江南通段辖区特点,对半潜船作业中的风险进行分析。

  5. Artificial neural network modeling of water quality of the Yangtze River system: a case study in reaches crossing the city of Chongqing

    Institute of Scientific and Technical Information of China (English)

    GUO Jin-song; LI Zhe

    2009-01-01

    An effective approach for describing complicated water quality processes is very important for fiver water quality management. We built two artificial neural network (ANN) models, a feed-forward back-propagation (BP) model and a radial basis function (RBF) model, to simulate the water quality of the Yangtze and Jialing Rivers in reaches crossing the city of Chongqing, P. R. China. Our models used the historical monitoring data of biological oxygen demand, dissolved oxygen, ammonia, oil and volatile phenolic compounds. Comparison with the one-dimensional traditional water quality model suggest that both BP and RBF models are superior; their higher accuracy and better goodness-of-fit indicate that the ANN calculation of water quality agrees better with measurement. It is demonstrated that ANN modeling can be a tool for estimating the water quality of the Yangtze River. Of the two ANN models, the RBF model calculates with a smaller mean error, but a larger root mean square error. More effort to identify out the causes of these differences would help optimize the su'uctures of neural network water-quality models.

  6. Remotely sensed variability of the suspended sediment concentration and its response to decreased river discharge in the Yangtze estuary and adjacent coast

    Science.gov (United States)

    Shen, Fang; Zhou, Yunxuan; Li, Jiufa; He, Qing; Verhoef, Wouter

    2013-10-01

    Satellite observation is an excellent tool for exploring the variability of the suspended sediment concentration (SSC) of turbid estuarine and coastal waters. We used a recently developed semi-empirical radiative transfer model combined with a multi-wavelength switching algorithm for the SSC retrieval from MEdium Resolution Imaging Spectrometer (MERIS) satellite data. This method can successfully retrieve SSC from satellite data in turbid estuarine and coastal waters with a wide range of sediment concentrations (20-2500 mg l-1) and is robust for quantifying realistic patterns of the surface sediment dynamics. The seasonal and annual variability of the MERIS-derived SSC from 2003 to 2010 were analysed in this work. Five regions-of-interest (ROIs) in the Yangtze estuary and coast are included in the analysis: the upper estuary, the lower estuary, the outer estuary, the Hangzhou Bay and the Qidong shore. The results reveal that the SSC of the upper estuary has significant seasonal and annual variations in response to seasonal cycling and annual fluctuation of the river discharge. A long-term continuing decrease of river discharge may cause an overall decline of the SSC in the entire estuary and adjacent areas. The existence of horizontal exchanges of the sediments between the Yangtze estuary and the Jiangsu coast implies that the decreased fluvial sediment loads of the estuary may partially be compensated by supplementing contributions from other origins.

  7. Relationship between the Late Spring NAO and Summer Extreme Precipitation Frequency in the Middle and Lower Reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    TTIAN Bao-Qiang; FAN Ke

    2012-01-01

    The relationship between the late spring North Atlantic Oscillation (NAO) and the summer extreme precipitation frequency (EPF) in the middle and lower reaches of the Yangtze River Valley (MLYRV) is examined using an NECP/NCAR reanalysis dataset and daily precipitation data from 74 stations in the MLYRV. The results show a significant negative correlation between the May NAO index and the EPF over the MLYRV in the subsequent summer. In positive EPF index years, the East Asian westerly jet shifts farther southward, and two blocking high positive anomalies appear over the Sea of Okhotsk and the Ural Mountains. These anomalies are favorable to the cold air from the mid-high latitudes invading the Yangtze River Valley (YRV). The moisture convergence and the ascending motion dominate the MLYRV. The above patterns are reversed in negative EPF index years. A wave train pattern that originates from the North Atlantic extends eastward to the Mediterranean and then moves to the Tibetan Plateau and from there to the YRV, which is an important link in the May NAO and the summer extreme precipitation in the MLYRV. The wave train may be aroused by the tripole pattern of the SST, which can explain why the May NAO affects the summer EPF in the MLYRV.

  8. Crustal and uppermost mantle velocity structure and its relationship with the formation of ore districts in the Middle-Lower Yangtze River region

    Science.gov (United States)

    Ouyang, Longbin; Li, Hongyi; Lü, Qingtian; Yang, Yingjie; Li, Xinfu; Jiang, Guoming; Zhang, Guibin; Shi, Danian; Zheng, Dan; Sun, Sanjian; Tan, Jing; Zhou, Ming

    2014-12-01

    In this study, we conduct ambient noise tomography and teleseismic two-plane-wave tomography to probe the crustal and uppermost mantle structures in the Middle-Lower Yangtze River region. The data used include 14 months (from July 2012 to August 2013) of continuous vertical component ambient noise data and 219 teleseismic earthquakes recorded at 138 broadband seismic stations from Chinese provincial networks and 19 temporary seismic stations deployed by China University of Geosciences (Beijing). First, we apply ambient noise tomography to the collected ambient noise data to generate Rayleigh wave group and phase velocity maps at 5-42 s periods and two-plane-wave tomography method to earthquake data to generate intermediate-to-long period phase velocity maps at 20-143 s periods. We then combine the short-to-intermediate period velocity maps from ambient noise and the intermediate-to-long period phase velocity maps from earthquake data to generate broadband phase velocity maps at periods from 5 to 143 s. By inverting these 5-143 s Rayleigh wave velocity maps, we construct a 3-D shear wave velocity model from the surface to ∼250 km depth in the Middle-Lower Yangtze River region. The 3-D model shows that in the upper crust, the basin regions, including the JiangHan, HeHuai, SuBei, HeFei and NanYang basins, are all featured with low velocities, and the mountain regions with high velocities. In the uppermost mantle, a low-velocity zone at ∼100-200 km depth is observed beneath the Middle-Lower Yangtze River Metallogenic Belt. Moreover, our tomographic results show that the NingWu and NingZhen ore districts are clearly characterized by the strongest low velocity anomaly in the uppermost mantle at ∼70-200 km depth. The depth extent of the low-velocity zone becomes shallower and the amplitude of low velocity anomaly becomes larger from the southwest JiuRui ore district to northeast NingWu ore districts. The change pattern of the low-velocity zone in the depth extent

  9. Source, transport and impacts of a heavy dust event in the Yangtze River Delta, China, in 2011

    Science.gov (United States)

    Fu, X.; Wang, S. X.; Cheng, Z.; Xing, J.; Zhao, B.; Wang, J. D.; Hao, J. M.

    2014-02-01

    Dust invasion is an important type of particle pollution in China. During 1 to 6 May in 2011, a dust event was observed in the Yangtze River Delta region (YRD). The highest PM10 (particles up to 10 μ in diameter) concentration reached over 1000 μg m-3 and the visibility was below 3 km. In this study, the Community Multi-scale Air Quality modeling system (CMAQ5.0) coupled with an in-line windblown dust model was used to simulate the formation, spatial and temporal characteristics of this dust event, and analyze its impacts. The threshold friction velocity for loose, fine-grained soil with low surface roughness in the dust model was revised based on Chinese data to improve the model performance. This dust storm broke out in Xinjiang and Mongolia during 28 to 30 April and arrived in the YRD region on 1 May. The transported dust particles contributed to the mean surface layer concentrations of PM10 in the YRD region 78.9% during 1 to 6 May with their impact weakening from north to south due to the removal of dust particles along the path. The dry deposition, wet deposition and total deposition of PM10 in the YRD reached 184.7 kt, 172.6 kt and 357.32 kt, respectively. The dust particles also had significant impacts on optical/radiative characteristics by absorption and scattering. In Shanghai, the largest perturbations of aerosol optical depth (AOD) and irradiance were about 0.8 DU and -130 W m-2, which could obviously influence the radiation balance in this region. The decrease of actinic fluxes impacts future photochemistry. In Shanghai, the negative effects on the NO2 and O3 photolysis could be -35% when dust particles arrived. The concentrations of O3 and OH were reduced by 1.5% and 3.1% in the whole of China, and by 9.4% and 12.1% in the YRD region, respectively. Such changes in O3 and OH levels can affect the future formation of secondary aerosols in the atmosphere by directly determining the oxidation rate of their precursors. The work of this manuscript is

  10. Identification of particulate organosulfates in three megacities at the middle and lower reaches of the Yangtze River

    Science.gov (United States)

    Wang, X. K.; Rossignol, S.; Ma, Y.; Yao, L.; Wang, M. Y.; Chen, J. M.; George, C.; Wang, L.

    2015-08-01

    PM2.5 filter samples have been collected in three megacities i.e., Wuhan (WH), Nanjing (NJ), and Shanghai (SH) at the middle and lower reaches of the Yangtze River, respectively. Analysis of those samples using an ultra-high performance liquid chromatography (UHPLC) coupled to an orbitrap mass spectrometer (MS) allowed detection of about two hundred particulate organosulfates (OSs), including dozens of nitrooxy-organosulfates, at each location. While aliphatic OSs represented more than 78 % of the detected OSs at the three locations, aromatic OSs were much less abundant. OSs with two to four isomers accounted for about 50 % of the total OSs on average in these megacities, and the percentage of OSs with six and more isomers in WH was more significant than those in SH and NJ. The average molecular weight, and the degrees of oxidation and saturation of OSs in the WH summer samples were greater than those in WH winter samples. In SH, the average molecular weight and the degree of oxidation of OSs in summer samples were greater than those in winter samples, but the degree of saturation was similar between the two seasons. In summer, the average molecular weight, and the degrees of oxidation and unsaturation of OSs were smallest in WH among the three cities. Between NJ and SH, the average molecular weight and the degree of saturation of OSs were close and the degree of oxidation of OSs in NJ was smaller. Kendrick mass defect diagrams and Van Krevelen diagrams indicated that the characteristics of identified OSs between in NJ and in SH shared better similarity. In addition, the identity and abundance of OSs in SH showed clear seasonal and diurnal variations. OSs in summer were more abundant than they were in winter due to stronger photochemical reactions in summer. The relative abundance of OSs at night was greater than that in the daytime and more nitrooxy-OSs existed at night, probably because of active NO3 radical chemistry at night. In SH summer samples, OSs with 5

  11. Ozone and fine particle in the western Yangtze River Delta: an overview of 1-yr data at the SORPES station

    Directory of Open Access Journals (Sweden)

    A. J. Ding

    2013-01-01

    Full Text Available This work presents an overview of 1-yr measurements of ozone (O3 and fine particular matter (PM2.5 and related trace gases at a recently developed regional background site, the Station for Observing Regional Processes of the Earth System (SORPES, in the western part of the Yangtze River Delta (YRD in East China. O3 and PM2.5 showed distinguished seasonal cycles but with contrast patterns: O3 reached a maximum in warm seasons but PM2.5 in cold seasons. Correlation analysis suggests a VOC-sensitive regime for O3 chemistry and also indicates a substantial formation of secondary aerosols under conditions of high O3 in summer. Compared with the National Ambient Air Quality Standards in China, our measurements report 15 days of O3 exceedance and 148 days of PM2.5 exceedance during the 1-yr period, suggesting a severe air pollution situation in this region. Case studies for typical O3 and PM2.5 episodes demonstrated that these episodes were generally associated with an air mass transport pathway over the mid-YRD, i.e. along the Nanjing-Shanghai axis with its city clusters, and showed that synoptic weather played an important role in air pollution, especially for O3. Agricultural burning activities caused high PM2.5 and O3 pollution during harvest seasons, especially in June. A calculation of potential source contributions based on Lagrangian dispersion simulations suggests that emissions from the YRD contributed to over 70% of the O3 precursor CO, with a majority from the middle-YRD. North-YRD and the North China Plain are the main contributors to PM2.5 pollution in this region, especially for the burning episode days. This work shows an important environmental impact from industrialization and urbanization in the YRD region, and suggests an urgent need for improving

  12. Modeling of the anthropogenic heat flux and its effect on air quality over the Yangtze River Delta region, China

    Directory of Open Access Journals (Sweden)

    M. Xie

    2015-11-01

    Full Text Available Anthropogenic heat (AH emissions from human activities caused by urbanization can affect the city environment. Based on the energy consumption and the gridded demographic data, the spatial distribution of AH emission over the Yangtze River Delta (YRD region is estimated. Meanwhile, a new method for the AH parameterization is developed in the WRF/Chem model, which incorporates the gridded AH emission data with the seasonal and the diurnal variations into the simulations. By running this upgraded WRF/Chem for two typical months in 2010, the impacts of AH on the meteorology and air quality over the YRD region are studied. The results show that the AH fluxes over YRD have been growing in recent decades. In 2010, the annual mean values of AH over Shanghai, Jiangsu and Zhejiang are 14.46, 2.61 and 1.63 W m−2 respectively, with the high values of 113.5 W m−2 occurring in the urban areas of Shanghai. These AH emissions can significantly change the urban heat island and urban-breeze circulations in the cities of the YRD region. In Shanghai, 2 m air temperature increases by 1.6 °C in January and 1.4 °C in July, the planetary boundary layer height rises up by 140 m in January and 160 m in July, and 10 m wind speed is enhanced by 0.7 m s−1 in January and 0.5 m s−1 in July, with higher increment at night. And the enhanced vertical movement can transport more moisture to higher levels, which causes the decrease of water vapor at the ground level and the increase in the upper PBL, and thereby induces the accumulative precipitation to increase by 15–30 % over the megacities in July. The adding AH can impact the spatial and vertical distributions of the simulated pollutants as well. The concentrations of primary air pollutants decrease near surface and increase at the upper levels, due mainly to the increases of PBLH, surface wind speed and upward air vertical movement. But surface O3 concentrations increase in the urban areas, with maximum changes

  13. Observation of aerosol size distribution and new particle formation at a coastal city in the Yangtze River Delta, China.

    Science.gov (United States)

    Shen, Lijuan; Wang, Honglei; Lü, Sheng; Li, Li; Yuan, Jing; Zhang, Xiaohan; Tian, Xudong; Tang, Qian

    2016-09-15

    Aerosol number size distribution in the range of 10nm-10μm, trace gases (O3, CO, SO2 and NO2), particular matter (PM: PM2.5 and PM10) and meteorological elements were measured from the 1st to the 31st of May, 2015, in the coastal city of Jiaxing in the Yangtze River Delta (YRD). The average number concentration and surface area concentration were 19,639cm(-3) and 427μm(2)cm(-3) during the observation period. The different mode particle concentrations ranked in the order of Aitken mode (12,361cm(-3))>nucleation (4926.7cm(-3))>accumulation (2349.3cm(-3))>coarse mode (1.7cm(-3)). The average concentrations of CO, SO2, NO2, O3, PM2.5 and PM10 were 0.545mgm(-3), 14.7, 35.1, 89.8, 43.5 and 64.6μgm(-3), respectively. Eight precipitation processes and 15 new particle formation (NPF) events (3 NPF events occurred on a rainy day) were observed. Results show that the precipitation process had greater scavenging effects on particles smaller than 120nm and larger than 2μm. The spectral distributions of number concentrations were unimodal at different weather conditions, with peaks at 20nm, 40-60nm, 50-80nm on NPF days, rainy days and normal days. During the NPF events, the formation rate (FR), growth rate (GR), condensational sink (CS), vapor source rate (Q) and condensing vapor concentration (C) were in the range of 4.0-17.0cm(-3)s(-1), 2.2-15.7nmh(-1), 1.5-5.8×10(-2)s(-1), 0.5-7.7×10(6)cm(-3)s(-1) and 3.0-21.5×10(7)cm(-3), with mean values of 9.6cm(-3)s(-1), 6.8nmh(-1), 3.4×10(-2)s(-1), 3.3×10(6)cm(-3)s(-1) and 9.4×10(7)cm(-3), respectively. NPF events normally occurred under clean atmospheric conditions with low PM concentrations but high levels of trace gases. It was also found that SO2 plays an important role in NPF and growth in Jiaxing. PMID:27261424

  14. Modeling of the anthropogenic heat flux and its effect on air quality over the Yangtze River Delta region, China

    Science.gov (United States)

    Xie, M.; Liao, J.; Wang, T.; Zhu, K.; Zhuang, B.; Han, Y.; Li, M.; Li, S.

    2015-11-01

    Anthropogenic heat (AH) emissions from human activities caused by urbanization can affect the city environment. Based on the energy consumption and the gridded demographic data, the spatial distribution of AH emission over the Yangtze River Delta (YRD) region is estimated. Meanwhile, a new method for the AH parameterization is developed in the WRF/Chem model, which incorporates the gridded AH emission data with the seasonal and the diurnal variations into the simulations. By running this upgraded WRF/Chem for two typical months in 2010, the impacts of AH on the meteorology and air quality over the YRD region are studied. The results show that the AH fluxes over YRD have been growing in recent decades. In 2010, the annual mean values of AH over Shanghai, Jiangsu and Zhejiang are 14.46, 2.61 and 1.63 W m-2 respectively, with the high values of 113.5 W m-2 occurring in the urban areas of Shanghai. These AH emissions can significantly change the urban heat island and urban-breeze circulations in the cities of the YRD region. In Shanghai, 2 m air temperature increases by 1.6 °C in January and 1.4 °C in July, the planetary boundary layer height rises up by 140 m in January and 160 m in July, and 10 m wind speed is enhanced by 0.7 m s-1 in January and 0.5 m s-1 in July, with higher increment at night. And the enhanced vertical movement can transport more moisture to higher levels, which causes the decrease of water vapor at the ground level and the increase in the upper PBL, and thereby induces the accumulative precipitation to increase by 15-30 % over the megacities in July. The adding AH can impact the spatial and vertical distributions of the simulated pollutants as well. The concentrations of primary air pollutants decrease near surface and increase at the upper levels, due mainly to the increases of PBLH, surface wind speed and upward air vertical movement. But surface O3 concentrations increase in the urban areas, with maximum changes of 2.5 ppb in January and 4

  15. The Changjiang sediment flux into the seas: measurability and predictability

    Institute of Scientific and Technical Information of China (English)

    Daowei YIN; Zhongyuan CHEN

    2009-01-01

    This paper examines the credibility and predictability of sediment flux of the Changjiang River that has discharged into the seas on the basis of historical database. The assumption of the study stands on the lack of sufficient observation data of suspended sediment con-centration (SSC) during peaking flood period, which most likely results in the application of an inappropriate method to the downstream-most Datong hydrological gauging station in the Changjiang basin. This insufficient method (only 30-50 times of SSC observation per year), that obviously did not cover the peaking SSC during peaking floods, would lead to an inaccuracy in estimating the Changjiang sediment load by 4.7×108t/a (multiyearly)into the seas. Also, sediment depletion that often takes place upstream of the Changjiang basin has, to some extent, lowered the credibility of traditional sediment rating curve that has been used for estimating sediment budget. A newly-established sediment rating curve of the present study is proposed to simulate the sediment flux/load into the seas by using those SSC only under discharge of 60000ma/s at the Datong station-the threshold to significantly correlate to SSC. Since discharge of 60000-80000 m3/s is often linked to extreme flood events and associated sediment depletion in the basin, un-incorporating SSC of 60000-80000 m3/s into the sediment rating curve will increase the credibility for sediment load estimation. Using this approach of the present study would indicate the sediment load of 3.3 × 108-6.6× 108 t/a to the seas in the past decades. Also, our analytical result shows a lower sediment flux pattern in the 1950s, but higher pattern in the 1960 s-1980 s, reflecting the changes in land-use in the upstream of Changjiang basin, including widely devastated deforestation during the middle 20th century.

  16. Biomonitoring of detoxifying activity as measured by CYP1A1 induction in Yangtze and Jialing Rivers in Chongqing City in China.

    Science.gov (United States)

    Cui, Zhihong; Liu, Jingyi; Li, Peng; Cao, Bo; Luo, Caihong; Cao, Jia

    2009-01-01

    In order to determine the potential toxicities of organic pollutants in the river water of Chongqing City (China), chemicals were extracted from surface water of the Yangtze River and Jialing River between August 2004 and January 2005. Gas chromatography/mass spectrometry (GC/MS) analysis showed that the main compounds detected were polycyclic aromatic hydrocarbons (PAH) and phthalate acid esters (PAE). The ethoxyresorufin O-deethylase (EROD) test showed that the toxic equivalency (TEQ) values of the samples ranged from 0.9 to 13.3 x 10(-4) pg 2,3,7,8-TCDD/L river water. Incubation of H4IIE cells with organic extracts produced a time-dependent induction of cytochrome P-450 1A1 (CYP1A1) mRNA expression as determined by (1) reverse-transcription polymerase chain reaction (RT-PCR), (2) positive binding to aryl hydrocarbon receptor (AhR), and (3) activation of xenobiotic response element (XRE) by electrophoretic mobility shift assay (EMSA). Data indicated that organic extracts from the river water of Chongqing City induced CYP1A1 activity in hepatocytes in vitro. A possible mechanism underlying toxicity might involve the AhR signal pathway, but further studies are necessary. PMID:19492243

  17. Assessment on Sustainability in Yangtze River Basin and Improvement%长江流域可持续发展能力评价

    Institute of Scientific and Technical Information of China (English)

    陈利顶; 傅伯杰

    2000-01-01

    阐述了可持续发展能力的概念和特点,提出了可持续发展能力评价的指标体系和方法。并以长江流域7省1市为例,从自然和经济的角度评价了长江流域各省市90年代以来可持续发展能力的动态变化。评价结果表明:90年代以来,长江流域各省区人工资本积累能力、人力资源和科学技术资源支持能力总体上为持续上升趋势,但各省区增长的速度略有差异;而自然资源的支持能力为不断下降趋势,同时人口压力还在不断加大;环境资源支持能力各省区变化趋势差异较大,反映出各地区由于对环境治理的重视程度和环境投资的差异。在此基础上提出了加强长江流域可持续发展能力建设的基本途径。%The Yangtze River basin covers about 1.8 million km2, taking about 15. 596 of total area of China,and about nine main administration regions are situated in this region. It goes through the central China fromwest to east. Since its rich land resource and water power resource, it plays a significant role in China' s nationalsustainable development. The population within the major nine administration regions in 1997 is about 0.47 bil-lion, the gross national product reaches 3 017 billion yuan(RMB) and the total grain yield is about 199 billionkg. They are respectively 38.4 %, 39.2 %, 40.3 % of the total amount of China in 1997. However, due to nat-ural eco-environmental difference among the lower, the middle and the upper parts of the Yangtze River basin,much difference on social, economic, cultural aspect is still remained for different administration regions. Thus,some practical difficulties are faced to realize sustainable development for the whole basin. In this study, based on analyzing the characteristics of sustainable development and concept, a reasonableapproach and index for assessing sustainability based on society, economy, technology, resource and ecologicalconservation was proposed

  18. Study on City Co-operation of Six Cities of Anhui in Pan-Yangtze River Delta Region%泛长三角地区安徽六市的城市经济合作研究

    Institute of Scientific and Technical Information of China (English)

    于阳; 朱云鹃; 朱学星

    2011-01-01

    基于主要经济联系方向论,利用区域相互作用引力模型,以安徽省相关城市参与泛长三角区域一体化建设为背景,计算了归入泛长三角地区的安徽六市与长三角地区核心城市——上海、南京、杭州的经济联系强度及经济联系隶属度。根据计算结果,对安徽六市进行了聚类分析,并提出了安徽六市参与泛长三角区域一体化建设的“双圆模式”以及与其他城市进行经济合作的具体内容和需要注意的问题。%Based on the classical economic geography theory,on the background of Anhui's joining in the regional integration construction in Pan Yangtze River Delta Region, this paper uses the gravity model amony different regions to calculate the economic relation intensity and the economic relation membership degree between six cities of Anhui province in Pan Yangtze River Delta Region and core cities in Yangtze River Delta Region,namely Shanghai,Nanjing and Hangzhou. According to the calculating results,it makes a cluster analysis. Then it puts forward the city cooperation mode of Anhuirs participating in the regional integration construction in Pan Yangtze River Delta Region,and the contents and details of economic cooperation of six cities of Anhui with other cities in Pan Yangtze River Delta Region.

  19. SHRIMP zircon U-Pb dating for volcanic rocks of the Dasi Formation in southeast Hubei Province, middle-lower reaches of the Yangtze River and its implications

    Institute of Scientific and Technical Information of China (English)

    XIE Guiqing; MAO Jingwen; LI Ruiling; ZHOU Shaodong; YE Huishou; YAN Quanren; ZHANG Zusong

    2006-01-01

    The Jinniu Basin in southeast Hubei,located at the westernmost part of middle-lower valley of the Yangtze River, is one of the important volcanic basins in East China. Volcanic rocks in the Jinniu Basin are distributed mainly in the Majiashan Formation, the Lingxiang Formation and the Dasi Formation, consisting of rhyolite, basalt and basaltic andesite, (trachy)-basalt and basaltic trachy-andesite and (trachy)-andesite and (trachy)-dacite and rhyolite respectively, in which the Dasi volcanism is volumetrically dominant and widespread. The Dasi volcanic rocks were selected for SHRIMP zircon U-Pb dating to confirm the timing of volcanism. The results indicate that there exist a large amount of magmatic zircons characterized by high U and Th contents in the volcanic rocks. The concordia ages for 13 points are 128±1Ma (MSWD = 3.0). On account of the shape of zircons and Th/U ratios, this age is considered to represent the crystallization time of the Dasi volcanism. The volcanic rocks in the Dasi, Majiashan and Lingxiang Formations share similar trace element and REE partition patterns as well as Sr-Nd isotopic compositions. In combination with the regional geology, it is proposed that the southeast Hubei volcanic rocks were formed mainly during the Early Cretaceous, just like other volcanic basins in middle-lower Yangtze valley. A lithospheric extension is also suggested for tectonic regime in this region in the Cretaceous Period.

  20. Schistosoma japonicum risk in Jiangsu province, People’s Republic of China: identification of a spatio-temporal risk pattern along the Yangtze River

    Directory of Open Access Journals (Sweden)

    Kun Yang

    2013-11-01

    Full Text Available The risk for Schistosoma japonicum infection in Jiangsu province, People’s Republic of China, was investigated by a mouse bioassay. Various investigations were conducted in the period 2009-2011 with the presentation here representing the summary of the results from 45-50 sites in the marshlands along the Yangtze River’s course through the province. Indices representing three aspects of the infection were collected to assess risk: (i the proportion of sentinel points where at least one mouse infection was recorded; (ii the proportion of infected mice at each of these sites; and (iii the average worm burdens. Directional distribution analysis and scan statistics were used to explore the spatio-temporal risk pattern. The spatial distribution was oriented along the Yangtze River and the directional distributions for the proportion of infected mice and mean worm burdens were similar for the positive sentinel sites. Four statistically significant clusters were detected in 2009, but only one in 2010 and 2011, respectively. Temporal windows for infection risk were seen in June and September. The study illustrates the utility of spatio-temporal analysis in assessing the risk for schistosomiasis. This approach should be useful with respect to surveillance and response that can be expected to be increasingly applied when moving from morbidity control to transmission control.

  1. Application of the indirect fluorescent antibody assay in the study of malaria infection in the Yangtze River Three Gorges Reservoir, China

    Directory of Open Access Journals (Sweden)

    Xiang Zheng

    2009-08-01

    Full Text Available Abstract Background China Yangtze Three Gorges Project (TGP is one of the biggest construction projects in the world. The areas around the Three Gorge Dam has a history of tertian malaria and subtertian malaria epidemic, but there are no overall data about malaria epidemics before the completion of the project. The objective of this study was to get a reliable baseline on malaria infection in the Yangtze River Three Gorges reservoir area and to provide reference data for future studies about the impact of the project on malaria epidemics. Methods Two surveys of malaria infection were carried out in area, at six-month intervals in May and October 2008. About 3,600 dual specimens blood film samples for parasite diagnosis and filter paper blood spots for serology (using the immunofluorescence antibody test were collected from the general population, including school populations, whenever possible. Results The overall percentage of positive response of the same population during post-transmission periods was about twice (1.40/0.72 of that in pre-transmission. Positive individuals under 15 years of age were detected in all the localities. Conclusion A certain extent of malaria infection existed in this area. Additional studies are needed to determine the length of malaria experience, and chemotherapeutic intervention as well as the distribution of main vectors for transmission in this area.

  2. Spatial and temporal variation of dissolved organic matter in the Changjiang: Fluvial transport and flux estimation

    Science.gov (United States)

    Bao, Hongyan; Wu, Ying; Zhang, Jing

    2015-09-01

    The Changjiang is the most important source of freshwater and dissolved organic matter (DOM) for the East China Sea. However, knowledge regarding the sources, seasonal fluxes, and fluvial transport of terrigenous DOM (tDOM) in the Changjiang is lacking. To fill this knowledge gap, we measured dissolved organic carbon (DOC) and dissolved lignin in water samples collected in the middle and lower Changjiang under different hydrological conditions. Additional samples were collected biweekly in the lower Changjiang. Through comparisons with other rivers, we found that the DOC in the Changjiang is mainly from soil organic matter and has a higher fraction of tDOM during flood. Mass balance model results indicate that approximately 33% of the dissolved lignin discharged into the middle and lower Changjiang is removed during its transport to the lower reach during both low-discharge and flood periods. Based on a comparison of the removal rates under these two contrasting hydrological conditions and considering the lower organic carbon content and fine grain size of the Changjiang's suspended particles, we speculate that the major process for the removal of dissolved lignin is sorption, and potentially flocculation by suspended particles. Changjiang discharges 1.4 ± 0.10 Tg yr-1 and 8.6 ± 0.30 Gg yr-1 DOC and dissolved lignin to the estuary during the period of July 2010 to June 2011, respectively. Seasonal distributions of DOC and dissolved lignin fluxes are controlled by water discharge, which will be affected by future climate change and the Three Gorges Dam.

  3. A century scale human-induced hydrological and ecological changes of wetlands of two large river basins in Australia (Murray) and China (Yangtze): development of an adaptive water resource management framework

    OpenAIRE

    G. R. Kattel; Dong, X.; X. Yang

    2015-01-01

    Recently, the provision of food and water resources of two of the world's large river basins, the Murray and the Yangtze, has been significantly altered through widespread landscape modification. Long-term sedimentary archives, dating back to past centuries, from wetlands of these river basins reveal that rapid, basin-wide development has reduced resilience of biological communities, resulting in considerable decline in ecosystem services, including water quality. In particu...

  4. 长江经济带内陆节点城市生态系统状态评价研究 ——以长江中游城市带为例%Study on evaluation of ecological system state of inland key cities of Yangtze River Economic Belt:case of cities in midstream of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    杨俊; 李争; 宋振江; 王津

    2016-01-01

    In the implementation of the Yangtze River Economic Belt Strategy, the open and development of inland cities caused great pressure on the urban ecological system. We carry out the comprehensive evaluation of ecological system pressure, state and response in 10 key cities of middle Yangtze River Basin. It shows that the industrial wastewater, waste gas and solid waste discharge are the main sources of the pressure on urban ecological system;the ecosystem health status of most cities in the urban belt of middle Yangtze River Basin is below the well level;strengthening the pollution treatment project investment, impro-ving the forest coverage and the green space area of the city plays an important role in reducing the pressure on urban ecological system.%在长江经济带战略的实施中,内陆城市开放发展对城市生态环境造成了较大的压力. 利用"压力-状态-响应"模型( PSR) ,对长江中游城市带的10座中心城市生态系统压力、状态和响应进行了综合评价. 评价结果表明:① 工业污水、废气和固体废弃物排放是城市生态系统产生压力的主要来源;② 长江中游城市带中大部分城市生态系统健康状态处于良好以下水平;③ 加强污染治理项目投资、提高城市森林覆盖率和绿地面积对减缓城市生态系统压力具有较大作用.

  5. Natural and anthropogenic impacts on biogeochemical cycle in Yangtze River basin: Source, transformation and fate of dissolved organic matter (DOM) characterized by 3-D fluorescence spectroscopy

    Science.gov (United States)

    Gan, Shuchai; Wu, Ying; Bao, Hongyan; Zhang, Jing

    2013-04-01

    Inland waters play an important role in the global carbon cycle as reactors for DOM cycling, transformation and transportation. With large amounts of terrestrial DOM, the Yangtze River is vital for coastal environment and ecosystem. In the context of climate change, it's critical to evaluate both hydrodynamic conditions and increasing human activities' impacts on biogeochemical cycle of DOM in Yangtze River across different climatic and hydrologic regions which are poorly understood. What's more, the hydrologic condition changes caused by the Three Gorges Dam (TGD, world's largest power station in terms of installed capacity) have recently proven to be a partition factor for fluvial particle. However, it's still an enigma for dissolved matter cycle. To address those issues, this study applies EEMs combined with bulk characteristics, chlorophyll and absorption spectrum in an attempt to assess characteristics and dynamics of DOM in Yangtze River. It's a novel optical approach that could 'see' molecular structure of DOM without the limits of time-consuming and laborious molecular measurements. Combined with parallel factor analysis, 5 individual fluorescent components have been identified: 3 humic-like (H1, H2, H3) and 2 protein-like components (P1, P2). With typical bioavailability and photo-reactivity, these components suggest different sources and dynamics. On the whole, both DOC and the sum of all 5 components (? Fluo) increased remarkably from the upper reach especially to the Three Gorge Dam and thereafter remained constant (R2between DOC and - Fluo: 0.92). The protein-like components (- P) accounted for 1/4 of - Fluo with apparently weak correlations with DOC and chlorophyll, which implied that the DOM is not dominated by autochthonous production, especially for the upper reach with high concentration of total suspended matter. As for Humic-like component, increasing H1 and DOC in the TGD reservoir area implied impacts from human activities there with intercept

  6. Data Organization and Operation Maintenance for the External Website of Yangtze River Scientific Research Institute%《长江水利科技网》的数据组织与运行维护

    Institute of Scientific and Technical Information of China (English)

    周力峰; 王奔

    2013-01-01

    为深入研究网站建设工作,基于《长江水利科技网》10余年的建设管理,从3个方面阐述了网站数据组织与运行维护工作.①数据规划:将数据源分类,建立数据源统计表,估算数据容量;按照数据标准,确定数据格式,以保障数据共享;以承载所需数据、保障足够空间、提供快速的数据提取能力和有健全的数据安全机制为原则,比选数据库平台.②数据管理:明确栏目责任单位和更新频率;选择不同类别数据的处理方式;选用可视化的后台编辑平台,采用数据接口或直接链接方式;以静态网页和动态网页相结合展现数据;采用全站题录级数据检索并向全文检索发展.③数据安全:通过设备配置、权限限制、数据备份等措施保障数据安全.分析成果表明,良好的数据规划、有效的数据管理和可靠的数据安全措施是网站运行维护的核心.%Data organization is recognized as the core of website operation and maintenance. On the basis of a decade ' s practice in building and maintaining the external website of Changjiang ( Yangtze) River Scientific Research Institute, we expound the data organization in terms of data planning during construction, data management and data security during operation and maintenance. For the data planning, the data source was classified and data source statistical tables were established to estimate data capacity; the data formats were determined to ensure data sharing ; proper database platform was selected in the light of adequate space, quick data extraction, and data security. Regarding data management, the responsible individual and updating frequency of columns were specified; various types of data were also differently treated; visualized backstage editing platform was adopted by data interface or direct links; static and dynamic web page were both employed to display the data; website-wide catalogue data retrieval has been developing

  7. Basement Characteristics and Crustal Evolution of the Copper-Gold Metallogenic Belt in the Middle and Lower Reaches of the Yangtze River: Some Isotope Constraints

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Studies of the Pb, Sr and Nd isotopic composition of Mesozoic intrusive rocks indicate that the basement of the copper-gold metallogenic belt of the middle and lower reaches of the Yangtze River has "two-layer structure" and partly has "multi-layered structure", and is inhomogeneous and shows the distinct feature of E-W provincialism. The calculated model lead ages (t1) are mostly greater than 2600 Ma, and the model neodymium ages (TDM) vary from 953 to 2276 Ma and concentrate in two time intervals: 1800- 2000 Ma and 1200- 1600 Ma. It is concluded that the basement of the MBYR is composed of the Late Archaeozoic to Middle Proterozoic metamorphic series and that the crust was initiated in the Archaean and continued to grow in the Early and Middle Proterozoic, and the proportion of new crust formed by mantle differentiation during the Late Proterozoic is low.

  8. Gardening arts of private gardens in south of the Yangtze River in Qing dynasty%清代江南私家园林的造园艺术

    Institute of Scientific and Technical Information of China (English)

    石岩

    2011-01-01

    以拙政园等著名园林为例,对其造园艺术从山水构架、光影表现等方面进行了论述,总结出以小见大、以水为魂、山石植物协调配置等特点,以期指导相关设计人员深入了解清代江南私家园林。%With Zhuozheng park and other famous parks as the example,it discusses the gardening arts from aspects of scenery structure and sunlight and shade embodiment,summarizes the features,such as seeing big things through small ones,takes water as the soul,coordination of mountain stone and plants,with a view to guide relevant designers to have deep understanding for south of the Yangtze River private gardens in Qing dynasty.

  9. The nutrient forms, cycling and exchange flux in the sediment and overlying water system in lakes from the middle and lower reaches of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    QIN; Boqiang

    2006-01-01

    This paper is a review of research works concerning the nutrient transportation,transformation and exchange between water, sediment and biota in the lakes from the middle and lower reaches of the Yangtze River conducted in the context of project entitled "The Processes and Mechanism of Lake Eutrophication in Middle and Lower Reaches of Yangtze River". All the lakes from this area are shallow lakes. According to the typical lake site research, the lakes from the middle and lower reaches of Yangtze River have a higher baseline of nutrition in the history. Normally the trophic status of these lakes can be categorized into medium-trophic or eutrophic. Human activities have been enhanced during the last decades, which speed up the lake eutrophic process. Lake eutrophication control needs to reduce not only the external nutrient inputs from watershed but also the internal loading from the sediments. Investigations revealed that the lake sediments in this area are considerablly high in nutrition in which at most about 30% of phosphorus exists in the form of bio-available in the sediment. The surface sediment will exert great effects on the nutrient exchange between water-sediment interface via adsorption and release of nutrient. The nutrient release from the sediment in these shallow lakes is mainly in two ways, i.e. in the undisturbed condition the nutrient is released through diffusion created by the nutrient gradient from sediment to overlying water; whereas in disturbed condition, the nutrient release is determined by the hydrodynamic forcing intensity and the sediment resuspension. Metallic elements such as the iron, manganese and aluminium and the aerobic-anaerobic ambience will affect the release of nutrients. The disturbed release will increase the total nutrients in the water column significantly in the short period. At the beginning of sediment resuspension, the dissolved nutrient concentration will increase. This increase will be damped if the ferric oxide and

  10. Climate history of the middle reach of the Yangtze river over the past 9000 years: A speleothem isotopic record from Za cave, Hubei, China

    Institute of Scientific and Technical Information of China (English)

    胡超涌; 黄俊华; 杨冠清; 林秀伦; 方念乔

    2001-01-01

    A stalagmite in Qingjiang, Hubei, has yielded the records of hydrogen and oxygen as well as carbon isotopic changes and provided a climate history of 9000 years. The hydrogen iso-topic ratio in fluid inclusions and the oxygen isotopic ratio in stalagmite calcite are controlled by meteoric water, which is in response to ambient temperature or precipitation amount. The carbon isotopic ratio, sensitive to the nature of vegetation, also can be used to reconstruct the climate history. The carbon-14 and U-series dated stalagmite records reveal that climate oscillated in the middle reach of Yangtze river over the past 9000 years:(1) 9.0-6.5 kaBP, a cooler and more humid condition; (2) 6.5-4.0 kaBP,with warmer and drier weather; (3) 4.0-2.0 kaBP, cold weather with heavy precipitation, and (4)2.0 kaBP to present, tendency to be warmer and drier.

  11. Spatio-temporal Variability of Northern Hemipheric Sea Level Pressure (SLP) and Precipitation overthe Mid-to-Low Reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    HAN Xue; WEI Fengying; Yves M.TOURRE; DONG Wenjie

    2008-01-01

    The spatio-temporal variability of Northern Hemisphere Sea Level Pressure (SLP) and precipitation over the mid-to-low reaches of the Yangtze River (PMLY) is analyzed jointly using the multi-taper /singular value decomposition method (MTM-SVD). Statistically significant narrow frequency bands are obtained from the local fractional variance (LFV) spectrum. Significant interdecadal (i.e., 16-to-18-year periods) and interannual (i.e., 3-to-6-year periods) signals are identified. Moreover, a significant quasi-biennial signal is identified but only for PMLY data. The spatial joint evolution of patterns obtained for peaks in the LFV spectrum sheds light on relationships between SLP and PMLY: the Arctic Oscillation (AO) modulates the variability of the PMLY while the interannual variability of PMLY is in phase with the Northern Atlantic Oscillation (NAO) and the Northern Pacific Oscillation (NPO).

  12. A century scale human-induced hydrological and ecological changes of wetlands of two large river basins in Australia (Murray) and China (Yangtze): development of an adaptive water resource management framework

    Science.gov (United States)

    Kattel, G. R.; Dong, X.; Yang, X.

    2015-08-01

    Recently, the provision of food and water resources of two of the world's large river basins, the Murray and the Yangtze, has been significantly altered through widespread landscape modification. Long-term sedimentary archives, dating back to past centuries, from wetlands of these river basins reveal that rapid, basin-wide development has reduced resilience of biological communities, resulting in considerable decline in ecosystem services, including water quality. In particular, large-scale human disturbance to river systems, due to river regulation during the mid-20th century, has transformed the hydrology of rivers and wetlands, causing widespread disturbance to aquatic biological communities. Historical changes of cladoceran zooplankton (water fleas) were used to assess the hydrology and ecology of three Murray and Yangtze River wetlands over the past century. Subfossil assemblages of cladocerans retrieved from sediment cores (94, 45 and 65 cm) of three wetlands: Kings Billabong (Murray), Zhangdu and Liangzi Lakes (Yangtze) strongly responded to hydrological changes of the river after the mid-20th century. River regulation caused by construction of dams and weirs, and river channel modifications has led to hydrological alterations. The hydrological disturbances were either: (1) a prolonged inundation of wetlands, or (2) reduced river flow, which caused variability in wetland depth. These phenomena subsequently transformed the natural wetland habitats, leading to a switch in cladoceran assemblages preferring poor water quality and eutrophication. An adaptive water resource management framework for both of these river basins has been proposed to restore or optimize the conditions of wetland ecosystems impacted by 20th century human disturbance and climate change.

  13. Potential utility of tree ring δ18O series for reconstructing precipitation records from the lower reaches of the Yangtze River, southeast China

    Science.gov (United States)

    Xu, Chenxi; Ge, Junyi; Nakatsuka, Takeshi; Yi, Liang; Zheng, Huaizhou; Sano, Masaki

    2016-04-01

    In this study, we investigated the interannual and intraannual variabilities in the oxygen isotope composition (δ18O) preserved in the tree ring cellulose of Pinus taiwanensis in the lower reaches of the Yangtze River, southeast China, to explore its potential utility for precipitation reconstruction over the period of 1855-2013. Intraannual variations of tree ring cellulose δ18O show distinct annual cycles that are characterized by δ18O maxima in the early growth near the ring boundary and δ18O minima in the middle and late portions of the ring. Seasonal patterns of tree ring δ18O were influenced by August-October typhoons. The tree ring cellulose δ18O was measured in both young and old trees to test for the juvenile effect. The results revealed no significant differences in the mean values and long-term trends in δ18O in the old and young trees. A response analysis indicated that tree ring δ18O correlated significantly with precipitation and relative humidity between May and October, and the δ18O chronology accounted for 37.4% of the actual variation in the May-October precipitation between 1951 and 2013. The extremely dry and wet years revealed by the tree ring δ18O-based reconstructed precipitation also corresponded to actual local drought and flood events from the documentary records. Reconstructed precipitation showed significant relationship with central tropical Pacific sea surface temperature, which indicated that El Niño-Southern Oscillation (ENSO) exerted influences on May-October precipitation in the lower reaches of the Yangtze River. In addition, the relationship between ENSO and precipitation weakened between 1920 and 1940, and low variance of ENSO from 1920 to 1940 may result in the damped ENSO's influences on precipitation in southeast China.

  14. 宜昌长江铁路大桥施工控制及仿真分析%Construction Control of the Yangtze River Railway Bridge in Yichang

    Institute of Scientific and Technical Information of China (English)

    陈晓梅

    2011-01-01

    Yichang Yangtze River Railway Bridge is a composite structure composed of prestressed concrete continuous rigid frame and concrete-filled steel tubular flexible arch,using the cantilever casting method for the construction.this paper regarded as an instance,modern control theory such as parameter identifying method is adopted in the stress control of Yichang Yangtze River Railway Bridge's constructing,the spatial finite element software MIDAS/CIVIL is selected to make a simulating analysis of overall process of the constructing.Judging by the generalization of stress and deflection changing rule in every stage of construction,the work of stress control is prepared for this bridge.Furthermore,Stress control is applied successfully by a perfect system of construction monitoring.%宜昌长江铁路大桥为连续刚构柔性拱组合结构,采用悬臂浇筑施工法进行施工。本文以该桥作为工程背景,运用现代控制理论,将参数识别法应用到施工控制中,采用专用空间有限元软件MI-DAS/CIVIL对其施工全过程进行仿真分析,通过对各施工阶段的应力和挠度变化规律的总结和完善的施工监测体系,对其应力控制进行成功的运用,取得了满意的效果。

  15. An analysis on the evolvement processes of lake eutrophication and their characteristics of the typical lakes in the middle and lower reaches of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    CHENG Xiaoying; LI Shijie

    2006-01-01

    According to the study on the aquatic environment of the typical lakes in the middle and lower reaches of Yangtze River, lake eutrophication is a process in which the lake ecosystem degenerates,resulting in the deterioration of the water quality due to the enrichment of the nutrients. Moreover, the succession of lake ecosystem and change of water quality both couple well with the evolvement of trophic state. Then the conceptual model is mentioned and ten lake states are classified. Based on these,the authors analyzed the eutrophication processes of the typical lakes in the middle and lower reaches of Yangtze River. The large lakes with taking in - sending out water typical of Poyang Lake evolve from State 1 before the 1980s into State 2 after the 1980s,the large and medium lakes typical of Taihu Lake evolve from State 1 -2 in the 1960s into State 8 in the 1980s then into State 9 in the 1990s, the medium and small shallow lakes typical of Honghu Lake evolve from State 1 in the 1960s into State 2 after the 1980s and the small city (suburban) lakes typical of Donghu Lake evolve from State 2 in the 1960s into State 9after the 1970s. Further, the 1980s is the key conversion period of the lakes of various types typical of Poyang Lake, Honghu Lake and Taihu Lake converting into mesotrophic state, the 1990s is that of Taihu Lake into eutrophic state and the 1970s is that of the small city (suburban) lakes typical of Donghu Lake into eutrophic state. The series of nutrient evolvement of different typical lakes are similar, but the processes are not synchronous, which is related to the various human and natural driving mechanisms in lake basins.

  16. Composition and changes in abundance and biomass of fish assemblages along the Jingjiang section of the Yangtze River over the last decade

    Directory of Open Access Journals (Sweden)

    Shasha Sun

    2013-11-01

    Full Text Available The Jingjiang section of the Yangtze River, which lies near the estuary with an irregular semidiurnal tide, is the National Aquatic Germplasm Resource Reserve and plays an important role in conserving fishery resources. To clarify the composition and changes in abundance/biomass of fish assemblages of these coastal waters, investigations were carried out along the Jingjiang section of the Yangtze River in the autumns of 2002 to 2011. Results showed that 91 species, belonging to 12 orders and 23 families, were collected from surveys conducted during this period. Fish included 47 species of Cypriniformes, 17 species of Perciformes and 10 species of Siluriformes. Four were migratory species, 13 were estuarine, and 74 were freshwater fish. The average number of different fish species recorded each autumn was 47 (range = 32–61, and mean Jaccard similarity index was 53.72 (range = 38.46–69.09%. The total number of dominant and common species recorded was 42, with the annual value averaging 19. Dominant and common species were mainly small fish, such as Hemiculter bleekeri, Pseudobrama simony, Pseudobagrus nitidus etc., as well as juveniles of large or medium fish, such as Culter alburnus, Parabramis pekinensis, P. vachellii etc. The mean individual weight (MIW of the fish assemblage was 6.99 g. The abundance biomass comparison curve indicated that the first dominant species recorded in autumn in all years except 2010 were all very small-sized fish. The most dominant species in 2002–2009 were also of small-size fish, and large-size fish only contributed to the dominant species in 2010 and 2011. Our research also indicated a general increase in abundance or biomass (CPUEN、CPUEW, the MIW of the fish assemblage, and the population size of 62% of dominant and common species. This suggested that fishery resources of the waters studied are likely to improve.

  17. A Summary of the Symposium on the Civilizing Course in the Upper Yangtze River Valley%长江上游地区文明化进程学术研讨会纪要

    Institute of Scientific and Technical Information of China (English)

    陈剑; 于春

    2005-01-01

    In 22 - 24 April, 2004, the Research Center of Ancient Civilization, IA, CASS, the Suchuan Provincial Institute of Cultural Relics and Archaeology, and the Chengdu Municipal Institute of Cultural Relics and Archaeology jointly held the “Symposium on the Civilizing Course in the Upper Yangtze River Valley.” At the meeting, exchanges and discussions were carried out mainly on the following topics: The Neolithic culture in Northwestern China. The southward spread of painted pottery from the upper Yellow River valley. The ritual institution in the Longshan period. Prehistoric city-sites on the Chengdu Plain. An analysis of the Sanxingdui culture elements. A Compositional analysis of the bronzes from the Jinsha site and those from the Three Gorges area. The chronology of the Paleolithic to the Qin-Han cultures in the Three Gorges and Yangtze River area. The origin and development of the Ba people and the Ba culture.

  18. Groundwater Pollution Characteristics and Hydrochemical Properties of Typical Plain River-net Area in Lower Yangtze River Delta, China: A Case Study in Suzhou City

    Science.gov (United States)

    Zhu, X.; Ruan, X.; Sun, H.; Pan, Z.

    2011-12-01

    Due to anthropogenic activities, tidal river water retention and other geological factors, groundwater quality in plain river-net area is vulnerable to pollution. Detailed chemical analysis results of 49 groundwater samples were carried out to identify groundwater pollution characteristics, hydrochemical properties and to assess groundwater quality and usability in Suzhou City, a typical plain area in Lower Yangtze River Delta, China. In order to protect, utilize and manage groundwater resources effectively, it is necessary to recognize the dominant processes responsible for hydrogeochemistry, groundwater pollution threats in study area. The results revealed ammonia concentration in confined and shallow groundwater ranges from 0.02 to 6.78 mg/L, 0.04 to 3.17 mg/L, respectively. Nitrite concentrations range from 0.004 to 1.01 mg/L, 0.004 to 3.66 mg/L, respectively. Iron concentrations range from 0.006 to 16.9 mg/L, 0.02 to 7.88 mg/L, respectively. Manganese concentrations range from 0.003 to 1.04 mg/L, 0.06 to 0.58 mg/L, respectively. On the basis of analytical results and water quality standards, majority of groundwater samples are not suitable for drinking, domestic as well as for industrial uses directly. Toxic metals and high levels ions should be removed if groundwater is supplied for different purposes. Salinity, sodium adsorption ratio, residual sodium carbonate and sodium percentage values revealed that most of groundwater samples are suitable for irrigation purposes except only a few. The salinity hazard of study area is regarded as low to medium, and special management for salinity control is required in scattered regions. Results of suitability for industrial purposes according to calculated Langeliar saturation index and Larson Ratio showed that majority of samples are calcium carbonate depositing, whereas a few are calcium carbonate dissolving in nature. Results show that sodium, calcium and bicarbonate are the dominant ions of groundwater. Na-HCO3

  19. Temporal-Spatial Evolution Analysis of Lake Size-Distribution in the Middle and Lower Yangtze River Basin Using Landsat Imagery Data

    Directory of Open Access Journals (Sweden)

    Lin Li

    2015-08-01

    Full Text Available Four natural lakes in the middle and lower reaches of the Yangtze River—Dongting Lake, Poyang Lake, Chaohu Lake and Taihu Lake—play a key role in the climate, environment, and ecology of this area. Upstream of these lakes, the Three Gorges Dam Project has been storing water for 12 years. Future monitoring and management of rivers and lakes can certainly benefit from research on the patterns of variation of natural lakes downstream of the Three Gorges Project. This research applies Landsat TM/ETM data to evaluate water area changes in the four lakes from 2002 to 2013. The water area is estimated using AWEI (Automated Water Extraction Index from satellite images. The average areas decreased respectively 452, 11, and 5 km2 (29.6%, 1.4% and 0.2% from 2002 to 2013 for Dongting, Chaohu, and Taihu Lakes. Meanwhile, it increased 300 km2 (11.0% for Poyang Lake. Precipitation and changes in river inflow may account for the fluctuation in the surface area to a large degree, especially between 2009 and 2013. The present study was undertaken to characterize the evolution of lakes and to explore the potential driving force of variation in order to assist the management of dams upstream in the river basin.

  20. Concentrations and distribution of organochlorine pesticides in shellfish from Changjiang estuary

    Institute of Scientific and Technical Information of China (English)

    MA Jizhen; SHEN Xinqiang; YUAN Qi; JIANG Mei

    2008-01-01

    To analyze and evaluate the status of organochlorine pollutants in the Changjiang (Yangtze River) estuary and adjacent waters, the concentrations of hexachlorocyclohexane (HCHs) and dichlorodiphenyltrichloroethane (DDTs) in shellfish collected in study area from 2006 to 2007 were determined with gas chromatography (GC). The concentration range of HCHs was (ND-12.13)×10-3 mg/kg wet weight and averaged at 0.54×10-3 mg/kg while the concentration of DDTs was in the range of (4.06-281.73) × 10-3 mg/kg with a mean of 57.52×10-3 mg/kg in the survey areas. The concentrations of DDTs in the shellfish were higher than HCHs', so that DDTs could be considered as typical organochlorine pollutants in the areas. The concentrations of DDTs in the shellfish were higher than HCHs', so that DDTs could be considered as typical organochlorines pollutants. The HCHs in all the shellfish conformed to the first level of criterion (0.02 mg/kg) of the Marion Biology Quality (GB 18421-2001), and that of DDTs in most samples were beyond the first level (0.01 mg/kg) but conformed to the second level (0.10 mg/kg). On average, α-HCH and δ-HCH occupied the most part of HCHs, while O,P'-DDT and P,P'-DDT occupied the most part of DDTs. The concentrations of organocholorine pesticides in shellfish samples varied in site and in species. The highest level occurred at the Shengsi (SS), followed by Yangkougang (YKG), Lvsi (LS), Dongyuan (DY) and Beibayao (BBY), low concentrations were observed at Changsha (CS), Beidaodi (BDD), and Gouqi (GQ). The concentration of HCHs and DDTs in most sites decreased clearly from 2006 to 2007 except for YKG, DY, BDD, LYS, and SS. All of above results suggested that the study area was slightly affected by organochlorine pesticide, special by DDTs.

  1. Hydrological response to urbanization at different spatio-temporal scales simulated by coupling of CLUE-S and the SWAT model in the Yangtze River Delta region

    Science.gov (United States)

    Zhou, Feng; Xu, Youpeng; Chen, Ying; Xu, C.-Y.; Gao, Yuqin; Du, Jinkang

    2013-04-01

    SummaryThe Main objective of the study is to understand and quantify the hydrological responses of land use and land cover changes. The Yangtze River Delta is one of the most developed regions in China with the rapid development of urbanization which serves as an excellent case study site for understanding the hydrological response to urbanization and land use change. The Xitiaoxi River basin, one of the main upstream rivers to the Taihu Lake in the Yangtze River Delta, was selected to perform the study. The urban area in the basin increased from 37.8 km2 in 1985 to 105 km2 in 2008. SWAT model, which makes direct use of land cover and land use data in simulating streamflow, provides as a useful tool for performing such studies and is therefore used in this study. The results showed that (1) the expansion of urban areas had a slight influence on the simulated annual streamflow and evapotranspiration (ET) as far as the whole catchment is concerned; (2) surface runoff and baseflow were found more sensitive to urbanization, which had increased by 11.3% and declined by 11.2%, respectively; (3) changes in streamflow, evapotranspiration and surface runoff were more pronounced during the wet season (from May to August), while baseflow and lateral flow had a slight seasonal variation; (4) the model simulated peak discharge increased 1.6-4.3% and flood volume increased 0.7-2.3% for the selected storm rainfall events at the entire basin level, and the change rate was larger for smaller flood events than for larger events; (5) spatially, changes of hydrological fluxes were more remarkable in the suburban basin which had a relative larger increase in urbanization than in rural sub-basins; and (6) analysis of future scenarios showed the impacts of urbanization on hydrological fluxes would be more obvious with growth in impervious areas from 15% to 30%. In conclusion, the urbanization would have a slight impact on annual water yield, but a remarkable impact was found on surface

  2. Assessment of limits and potentials of SWOT data for inland water bodies characterization and monitoring based on simulated data: Application to the Yangtze river complex

    Science.gov (United States)

    Yesou, Herve; Blumstein, Denis; Uribe, Carlos; Cretaux, Jean Francois; Huber, Claire; Daillet, Sylviane; Giraud, Henri; Gennero, Marie-Claude

    2013-04-01

    Capability of altimetry to be a powerful tool for inland water surfaces survey has already been demonstrated. Therefore, the SWOT mission expected for 2020, due to its innovative concept in term of swath and INSAR technology, will provide a major improvement for the understanding of inland water bodies spatial and temporal behaviors allowing a large range of applications in terms of reservoirs monitoring, flood hydraulics as well as drought episode characterizations or wetlands mapping and monitoring. Within the CNES SURFAC SWOT programme, it is proposed to explore the potential and limits of SWOT data for water elevations maps derivation. To succeed in this task, SWOT data will be simulated thank to a JPL-CNES simulator, integrating HR DEM developed from Tandem X data and Pleiades HR tri-stereo set, collection of water masks acquired with a high temporal frequency up to 5 days, HR and VHR land cover masks, historical Altimetric mission measurements and in situ gauge measurements. The Yangzte watershed has been selected due to its unique characteristics and human, economic and biodiversity stakes. Indeed intermediate and lower reaches of the Yangtze can be schematized as 600km long, very narrow, ie 1 to 2km, reservoir, with about 15 to 20 meters of water height dynamic within a year. Yangtze river by itself can be resumed as a 1000 km long river, with a 1 km rived bed. One of interest of the area in term of SWOT mission assessment is the lakes; the two first fresh water bodies of China, Dongting and Poyang lakes, as well as the smaller Anhui province lakes. Dongting and Poyang lakes are connecting with Yangtze and are controlled by its behaviors. These lakes' surfaces vary from dry to wet season respectively from 500 to 2500 km2, and 700 to 3500 km2, with water height variations of about 5 to 12 meters. The Anhui lakes will be the smallest targeted water bodies within the project, with surfaces about 100 km2 and less, with a width of a few kilometers. One

  3. 基于MODIS的长江中游河段悬浮泥沙浓度反演%MODIS-BASED RETRIEVAL AND CHANGE ANALYSIS OF SUSPENDED SEDIMENT CONCENTRATION IN MIDDLE YANGTZE RIVER

    Institute of Scientific and Technical Information of China (English)

    乔晓景; 何报寅; 张文; 李元征; 苏振华

    2013-01-01

    Monitoring and forecasting of the distribution and temporal change of SCC (suspended sediment concentration)is very important both for river water conservancy project and river ecology and environment protection.Retrieving SCC by remote sensing can compensate for the deficiency of the traditional timeconsume sampling method which acquires discrete data at high cost,and it provides information of SCC nearly in real-time at large-scale.So far,the Three Gorges Project has been used nearly ten years,meanwhile the impoundment of the reservoir will fundamentally change SCC of the suspended of the Yangtze River water in time and space,its influence is a matter of concern.This study took the middle reaches of the Yangtze River as the study area.It aimed to develope the Moderate-resolution Imaging Spectroradiometer (MODIS) image-based SSC retrieval model for Middle River,use the model to predict the SSC of Middle Yangtze River during the flood period from 2002 to 2009,and analyze its spatial and temporal change characteristics.The results revealed that:the red band of MODIS Terra was significantly related to the SCC,and it may be applied to retrieve the SSC of Middle Yangtze River during the flood period.This study selected three images.After inversion,three sediment concentration profiles from 2002 to 2009 were obtained,in order to contrast SCC of the Yangtze River in wet season before and after the impoundment of the Three Gorges Project.During 2002-2009 years,the SCC from the Yangtze River downstream of the dam was reduced significant.In addition,the sediment from the Yangtze River into the Dongting Lake was also reduced significantly.SCC mainly concentrated in the 300-400 mg/L from Yichang to Chenglingji in the period of wet season in 2002,and it reduced to 150-200 mg/L or so in 2009.During 2002-2009 period,24.2% of the total area of the concentration reduced by 100-150 mg/L,48.4%of the total area of the concentration reduced by 150-200 mg/L.The Dongting Lake inflow

  4. Geochemistry and Nd Sr isotopic studies of Late Mesozoic granitoids in the southeastern Hubei Province, Middle Lower Yangtze River belt, Eastern China: Petrogenesis and tectonic setting

    Science.gov (United States)

    Xie, Guiqing; Mao, Jingwen; Li, Ruiling; Bierlein, Frank P.

    2008-08-01

    A geochemical and isotopic study was carried out for the Mesozoic Yangxin, Tieshan and Echeng granitoid batholiths in the southeastern Hubei Province, eastern China, in order to constrain their petrogenesis and tectonic setting. These granitoids dominantly consist of quartz diorite, monzonite and granite. They are characterized by SiO 2 and Na 2O compositions of between 54.6 and 76.6 wt.%, and 2.9 to 5.6 wt.%, respectively, enrichment in light rare earth elements (LREE) and large ion lithophile elements (LILE), and relative depletion in Y (concentrations ranging from 5.17 to 29.3 ppm) and Yb (0.34-2.83 ppm), with the majority of the granitoids being geochemically similar to high-SiO 2 adakites (HSA). Their initial Nd ( ɛNd = - 12.5 to - 6.1) and Sr (( 87Sr/ 86Sr) i = 0.7054-0.7085) isotopic compositions, however, distinguish them from adakites produced by partial melting of subducted slab and those produced by partial melting of the lower crust of the Yangtze Craton in the Late Mesozoic. The granitoid batholiths in the southeastern Hubei Province exhibit very low MgO ranging from 0.09 to 2.19 wt.% with an average of 0.96 wt.%, and large variations in negative to positive Eu anomalies (Eu/Eu * = 0.22-1.4), especially the Tieshan granites and Yangxin granite porphyry (Eu/Eu * = 0.22-0.73). Geochemical and Nd-Sr isotopic data demonstrate that these granitoids originated as partial melts of an enriched mantle source that experienced significant contamination of lower crust materials and fractional crystallization during magma ascent. Late Mesozoic granitoids in the southeastern Hubei Province of the Middle-Lower Yangtze River belt were dominantly emplaced in an extensional tectonic regime, in response to basaltic underplating, which was followed by lithospheric thinning during the early Cretaceous.

  5. Seasonal variation of DO and formation mechanism of bottom water hypoxia of Changjiang River Estuary%长江口水体溶解氧的季节变化及底层低氧成因分析

    Institute of Scientific and Technical Information of China (English)

    李宏亮; 陈建芳; 卢勇; 金海燕; 王奎; 张海生

    2011-01-01

    利用2006-2007年“908-ST04区块”任务单元在长江口开展的春、夏、秋、冬四季多学科综合调查资料,分析了长江口水体溶解氧的季节变化,探讨了其底层低氧的形成机制,结果表明:冬季,表层和底层水体溶解氧值总体上呈近岸高、外陆架低的分布趋势,水体上下混合均匀;春季,藻华开始出现,水体层化初成,外陆架入侵的低溶解氧浓度水团和上层沉降的生物碎屑,使水体的低氧状况开始发展;夏季,在长江口锋面北侧底层水体中呈现1个“低氧带”,溶解氧最小浓度为2 mg/L;秋季,在122.5°E以东的陆架区,可观测到呈块状分布的溶解氧低值区和夏季缺氧核心区的残留.由于受人文活动和自然变化的双重影响,长江口水动力因素和生态响应复杂多变.长江冲淡水的扩散为该区域水体的缺氧提供了营养盐支持,台湾暖流水入侵和上升流为缺氧水体提供了较小的溶解氧背景值,而强烈的水体层化阻止了底层氧和上层高氧带的垂直交换.颗粒有机碳和总溶解有机碳的分布趋势表明,陆源有机质对低氧的贡献可能是有限的.%Seasonal variations of Dissolved Oxygen (DO) concentration in the water samples from Changjiang River Estuary and adjacent area were analyzed, which were obtained during 2006 and 2007 cruises. In winter, DO concentration was higher in the outer shelf than that in the coast area and homogeneous in the water column. In spring, water column stratification, algae bloom and the settling organic matter consumed the preformed low oxygen provided necessary conditions for the development of bottom water hypoxia. In summer, there was a "low oxygen zone" in the northern of the front with the minimum value was 2. 0 mg/L. In autumn, low concentration patches were observed in the east area of 122. 5°E, these maybe the residue of summer hypoxia. Because of the mixed influence of anthropogenic activity and natural variation

  6. Using a dual isotopic approach to trace sources and mixing of sulphate in Changjiang Estuary, China

    Energy Technology Data Exchange (ETDEWEB)

    Li Siliang, E-mail: lisiliang@vip.skleg.cn [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Liu Congqiang; Patra, Sivaji [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China); Wang Fushun [Institute of Applied Radiation, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 201800 (China); Wang Baoli; Yue Fujun [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002 (China)

    2011-06-15

    Highlights: > Changjiang Estuary plays an important role in transportation of the water and solute. > The dual isotopic method could be used to understand sulfate biogeochemistry in estuaries. > Mixing processes should be a major factor involved in the distribution of water and sulphate. > Sulphate in the Changjiang River mainly derived from atmospheric deposition, evaporite dissolution and sulphide oxidation. - Abstract: The dual isotopic compositions of dissolved SO{sub 4}{sup 2-} in aquatic systems are commonly used to ascertain SO{sub 4}{sup 2-} sources and possible biogeochemical processes. In this study, the physical parameters, major anions and isotopic compositions of SO{sub 4}{sup 2-} in water samples from Changjiang River (Nanjin) to the East Sea in Changjiang Estuary were determined. The salinity ranged from 0 per mille to 32.3 per mille in the estuary water samples. The Cl{sup -},SO{sub 4}{sup 2-} concentrations and {delta}{sup 18}O-H{sub 2}O values followed the salinity variations from freshwater to seawater, which indicated that mixing processes might be a major factor involved in the distribution of water and solutes. The contents and isotopic compositions of SO{sub 4}{sup 2-} suggested that atmospheric deposition, evaporite dissolution and sulphide oxidation were the major sources of dissolved SO{sub 4}{sup 2-} in the freshwater of Changjiang River. In addition, the mixing model calculated by contents and isotopic compositions of SO{sub 4}{sup 2-} indicated that the mixing of freshwater and sea water was the major factor involved in SO{sub 4}{sup 2-} distribution in Changjiang Estuary. However, slightly elevated {delta}{sup 18}O-SO{sub 4} values were observed in the turbidity maximum zone, which suggested that biological processes might affect the O isotopic compositions of SO{sub 4}{sup 2-} there.

  7. Coordination of Industrial Structure and Spatial Structure in Yangtze River Delta%长三角区域工业结构调整及其空间布局研究

    Institute of Scientific and Technical Information of China (English)

    陈君; 刘天晓; 向淑阳

    2011-01-01

    This paper analyzed the industrial structure features of Yangtze River Delta with shit share method.It indicates that the industrial structure of Yangtze River Delta is not so reasonable,Shanghai industrial competitiveness is weak,but it is strong in Jian%本文采用偏离份额分析法分析了长三角区域产业结构基本特征,特别分析了江浙沪三地工业结构发展现状,研究表明长三角区域工业结构并不十分合理,上海产业竞争力薄弱,而江苏产业竞争力较强。最后根据长三角工业结构存在的问题,提出工业结构及空间布局调整的建议。

  8. Numerical study of upwelling of the Changjiang River Estuary and its adjacent sea area in summer%夏季长江口外海区域上升流现象的数值研究

    Institute of Scientific and Technical Information of China (English)

    白涛; 杨德周; 尹宝树

    2009-01-01

    Based on the ECOMSED model(Blumberg et al.,1996),a research has been done to analyze the dynamic mechanisms of the upwelling of the Changjiang River Estuary and its adjacent sea area in summer.In order to improve the reliability of upwelling simulation of CRE and its adjacent sea area,the impacts of river flow,wind,circulation,heat flux and tides(including M_2,S_2,K_1,O_1)are taken into account.The result of simulation suggests that the upwelling is mainly induced by the Ekman effect caused by Taiwan Warm Current and continental slope rising.Local tides is not a main effect.%基于Blumberg等(1996)的ECOMSED模式,对长江口外海区域夏季的上升流现象进行了数值模拟.模式综合考虑径流,风应力,环流,热通量和M_2,S_2,K_1,O_1四个主要分潮的作用,从而提高长江口外海区域上升流模拟的准确性和可靠性,并通过各种控制实验分析了其动力机制,进一步说明本区域影响上升流的主要因子.数值实验表明,长江口外水下河谷的南边(杭州湾口门中心东侧),上升流主要是由向北流动的台湾暖流通过底Ekman效应和陆坡的抬升共同作用产生的.夏季偏南风对长江口外水下河谷西侧上升流的产生有一定影响,但作用不大.此外,潮汐潮流对上升流的产生也起着一定的作用,但在本文关注的上升流区潮作用影响不大.

  9. 长江南通段水域半潜作业浅析%Elementary Analysis of Semi-submersible Operations in Nantong Section Water Area of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    韩超; 汤嘉辉

    2012-01-01

      In recent years, the speed of semi-submersible ships market development is swift and violent. With both sides of the Yangtze River shipping industry's rapid development, the Nantong section water area of the Yangtze River, semi-submersible operations are increasing. Nantong is located in the Yangtze River Estuary, water area under administration in semi-submersible operations have the advantage be richly endowed by nature. In this paper, it describes the analysis of the Nantong section water area of the Yangtze River in recent years' semi-submersible operations, induction and analysis the advantages and disadvantages. At the same time, it provides relevant suggestions of semi-submersible in this area.%  近年来,半潜船市场发展速度较为迅猛,随着长江两岸船舶产业的迅速发展,长江南通段水域半潜作业也日益增多。南通位于长江入海口,辖区水域在进行半潜作业方面有着得天独厚的优势。文中通过分析长江南通段近几年来的半潜作业情况,归纳分析长江南通段水域半潜作业的优劣势,同时为辖区半潜作业提供相关的建议。

  10. Advantages of a city-scale emission inventory for urban air quality research and policy: the case of Nanjing, a typical industrial city in the Yangtze River Delta, China

    OpenAIRE

    Zhao, Y.; L. P. Qiu; Xu, R.Y.; F. J. Xie; Q. Zhang; Y. Y. Yu; C. P. Nielsen; H. X. Qin; H. K. Wang; Wu, X.C.; W. Q. Li; J. Zhang

    2015-01-01

    With most eastern Chinese cities facing major air quality challenges, there is a strong need for city-scale emission inventories for use in both chemical transport modeling and the development of pollution control policies. In this paper, a high-resolution emission inventory (with a horizontal resolution of 3 × 3 km) of air pollutants and CO2 for Nanjing, a typical large city in the Yangtze River Delta, is developed, incorporating the best available information on local sour...

  11. Geochemistry of the Dissolved Load of the Changjiang Basin Rivers: Anthropogenic Impacts and Chemical Weathering, Evidences from Major Elements, Sr and B Isotopes

    Institute of Scientific and Technical Information of China (English)

    Benjamin Chetelat; LIU Cong-qiang

    2008-01-01

    @@ 1 Introduction Rivers provide a unique opportunity to have average information about chemical and physical erosion, about the major geochemical fractionations created by these major geological processes but also about the impact and disturbances of human activities on the Earth Engine.

  12. 长江口中国花鲈食性分析%Feeding habits of Lateolabrax maculatus in Yangtze River estuary

    Institute of Scientific and Technical Information of China (English)

    洪巧巧; 庄平; 杨刚; 张涛; 侯俊利; 章龙珍; 智玉龙; 张航利; 杨阳

    2012-01-01

    above were all dominant food items of L. maculatus. The value of prey diversity measured for L. maculatus was 2.484 which are considered moderate level, thus making fairly easy to find anyone of the 27 prey items from samples of L. maculatus's. The result of feeding habits for L. maculatus is unlike previous studies, and there were obvious changes among the dominant species. According to analysis of the dates of PCA, differences of food items for two sampling points and the entire sets of Yangtze Estuary were being emerged. There were significant dietary shifts among samples from points of Tuanjiesha, Dongwangsha and the entire sets of Yangtze River estuary. According to principal components analysis, it is speculated that the difference is mainly caused by Coilia spp. , Glossogobius giuris, Exopalaemon carinicauda and Gnorimosphaeroma rayi.

  13. A comparison study of summer-time synoptic-scale waves in South China and the Yangtze River basin using the TRMM Multi-Satellite Precipitation Analysis daily product

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Summer-time synoptic-scale waves in South China and the Yangtze River basin are quantified and compared by means of analyzing the 6-year (1998―2004) TRMM Multi-Satellite Precipitation Analysis (TMPA) daily product. An innovative 3-dimensional spectrum analysis method is applied. The results indicate that synoptic-scale waves appearing in South China prominently propagate westward within a zonal wavenumber range of 9―21 and a frequency range of-0.12―-0.22 cycles day-1, while those in the Yangtze River basin primarily move eastward with the same characteristic wavenumbers of 9―21, but within a frequency range of 0.2―0.29 cycles day?1. Zonal and meridional distributions, and seasonal variations of these waves are further explored and compared. It shows that summer-time synoptic-scale waves in the South China result from the northward migration and oscillation of the Intertropical Convergence Zone (ITCZ) in the western Pacific, whereas the ones in the Yangtze River basin are generally related to the synoptic troughs within the westerly flow, originating from the Qinghai-Tibet Plateau.

  14. A comparison study of summer-time synoptic-scale waves in South China and the Yangtze River basin using the TRMM Multi-Satellite Precipitation Analysis daily product

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Summer-time synoptic-scale waves in South China and the Yangtze River basin are quantified and compared by means of analyzing the 6-year (1998-2004) TRMM Multi-Satellite Precipitation Analysis (TMPA) daily product. An innovative 3-dimensional spectrum analysis method is applied. The results indicate that synoptic-scale waves appearing in South China prominently propagate westward within a zonal wavenumber range of 9-21 and a frequency range of -0.12--0.22 cycles day?1, while those in the Yangtze River basin primarily move eastward with the same characteristic wavenumbers of 9-21, but within a frequency range of 0.2-0.29 cycles day-1. Zonal and meridional distributions, and seasonal variations of these waves are further explored and compared. It shows that summer-time synoptic-scale waves in the South China result from the northward migration and oscillation of the Intertropical Convergence Zone (ITCZ) in the western Pacific, whereas the ones in the Yangtze River basin are generally related to the synoptic troughs within the westerly flow, originating from the Qinghai-Tibet Plateau.

  15. Rural Residents′Tourism Motivation and Influence on Choice of Tourism Destination Classification:A Case of the Changjiang River Delta Region%农村居民旅游动机分析及其对旅游目的地类型选择的影响研究--以长江三角洲地区为例

    Institute of Scientific and Technical Information of China (English)

    卞显红; 王慧; 施琳霞

    2016-01-01

    以长江三角洲地区为例,首先采用主成分分析法分析农村居民旅游动机,然后通过构建对数回归方程研究旅游动机对“现代化的大城市”、“中小城市”、“历史文化城市”、“旅游城镇”、“山区”和“乡村旅游地”等六大旅游目的地选择的影响程度。研究结果表明:①长江三角洲农村居民外出旅游动机主要停留在观光游览层次。②长江三角洲农村居民对探亲访友旅游动机的赞同感知度较低,但探亲访友对于不同目的地选择具有一定影响。③长江三角洲农村居民外出旅游非常重视通过旅游能提升其在家人、亲戚、朋友中的地位与声望的功能。④旅游安全问题对提升农村居民出游力非常重要,同时农村居民非常注重旅游目的地住宿设施能营造家外之家的感觉。%Motivation is an important factor that determines behavior and the relationship between tourism moti-vation, destination choice is the key to forecast the future travel model. In the Changjiang River Delta Region, with the rural residents’income and consumption level increased and the willingness to travel strengthened, understanding the tourism motivation and its influence on tourism destination choice is significant for this re-gion’s tourism market development. Taking the Changjiang River Delta Region for example, this research ana-lyzes tourism motivation of rural residents with the method of principal component analysis by dividing 24 mo-tivation variables into 5 factors. And it studies how these motivations influence the choice of six tourism desti-nation such as“the modern big city”,“small city”,“historical and cultural city”,“tourist town”,“mountain-ous area”and“rural areas”by building logarithmic regression equation. The destination choice is the key to forecast the future travel model. The results show that:1) Tourism motivations of rural residents in the

  16. Source apportionment of fine particles and its chemical components over the Yangtze River Delta, China during a heavy haze pollution episode

    Science.gov (United States)

    Li, L.; An, J. Y.; Zhou, M.; Yan, R. S.; Huang, C.; Lu, Q.; Lin, L.; Wang, Y. J.; Tao, S. K.; Qiao, L. P.; Zhu, S. H.; Chen, C. H.

    2015-12-01

    An extremely high PM2.5 pollution episode occurred over the eastern China in January 2013. In this paper, the particulate matter source apportionment technology (PSAT) method coupled within the Comprehensive air quality model with extensions (CAMx) is applied to study the source contributions to PM2.5 and its major components at six receptors (Urban Shanghai, Chongming, Dianshan Lake, Urban Suzhou, Hangzhou and Zhoushan) in the Yangtze River Delta (YRD) region. Contributions from 4 source areas (including Shanghai, South Jiangsu, North Zhejiang and Super-region) and 9 emission sectors (including power plants, industrial boilers and kilns, industrial processing, mobile source, residential, volatile emissions, dust, agriculture and biogenic emissions) to PM2.5 and its major components (sulfate, nitrate, ammonia, organic carbon and elemental carbon) at the six receptors in the YRD region are quantified. Results show that accumulation of local pollution was the largest contributor during this air pollution episode in urban Shanghai (55%) and Suzhou (46%), followed by long-range transport (37% contribution to Shanghai and 44% to Suzhou). Super-regional emissions play an important role in PM2.5 formation at Hangzhou (48%) and Zhoushan site (68%). Among the emission sectors contributing to the high pollution episode, the major source categories include industrial processing (with contributions ranging between 12.7 and 38.7% at different receptors), combustion source (21.7-37.3%), mobile source (7.5-17.7%) and fugitive dust (8.4-27.3%). Agricultural contribution is also very significant at Zhoushan site (24.5%). In terms of the PM2.5 major components, it is found that industrial boilers and kilns are the major source contributor to sulfate and nitrate. Volatile emission source and agriculture are the major contributors to ammonia; transport is the largest contributor to elemental carbon. Industrial processing, volatile emissions and mobile source are the most significant

  17. FIELD OBSERVATIONS ON BED SEDIMENTS AND SANDWAVES IN CHANGJIANG ESTUARY

    Institute of Scientific and Technical Information of China (English)

    Jiufa LI; Xinning WAN; Ming YING; Xiaohua CHEN

    2005-01-01

    A series of advanced instruments were applied to obtain the field data of bed, bed forms and relevant dynamic factors in the 150 km-long reach of the Changjiang River from Jiangyin to Hengsha Island in March 2002. We found that well-sorted fine sand was in the majority of the bed sediment, which had a median diameter of 2φ. Well-developed sandwaves were formed because the grains jumped together on the bed, which was related to the granularity and current velocity during the flood-ebb tidal cycles.

  18. Diversity and distribution of amoA-type nitrifying and nirS-type denitrifying microbial communities in the Yangtze River estuary

    Science.gov (United States)

    Zhang, Y.; Xie, X.; Jiao, N.; Hsiao, S. S.-Y.; Kao, S.-J.

    2014-04-01

    Coupled nitrification-denitrification plays a critical role in the removal of excess nitrogen, which is chiefly caused by humans, to mitigate estuary and coastal eutrophication. Despite its obvious importance, limited information about the relationships between nitrifying and denitrifying microbial communities in estuaries, and their controlling factors have been documented. We investigated the nitrifying and denitrifying microbial communities in the estuary of turbid subtropical Yangtze River (YRE), the largest river in Asia, by analyzing the ammonia monooxygenase gene amoA, including archaeal and bacterial amoA, and the dissimilatory nitrite reductase gene nirS using clone libraries and quantitative PCR (qPCR). The diversity indices and rarefaction analysis revealed a quite low diversity for both β-proteobacterial and archaeal amoA genes, but qPCR data showed significantly higher amoA gene copy numbers for archaea than β-proteobacteria. Compared with the amoA gene, a significantly higher level of diversity but lower gene copy numbers were found for the nirS gene. Nitrification and denitrification rates based on 15N incubation experiments supported gene abundance data as denitrification rates were below detection limit, suggesting lower denitrification than nitrification potential. In general, the abundances of the amoA and nirS genes were significantly higher in the bottom samples than the surface ones, and in the high-turbidity river mouth, were significantly higher in the particle-associated (> 3 μm) than the free-living (0.2 ~ 3 μm) communities. Notably, positive correlations between the amoA and nirS gene abundances suggested potential gene-based coupling between nitrification and denitrification, especially for the particle-associated assemblages. Statistical analysis of correlations between the community structure, gene abundances and environmental variables further revealed that dissolved oxygen and total suspended material might be the key factors

  19. Effect of river discharge and geometry on tides and net water transport in an estuarine network, an idealized model applied to the Yangtze Estuary

    Science.gov (United States)

    Alebregtse, N. C.; de Swart, H. E.

    2016-07-01

    Tidal propagation in, and division of net water transport over different channels in an estuarine network are analyzed using a newly developed idealized model. The water motion in this model is governed by the cross-sectionally averaged shallow water equations and is forced by tides at the seaward boundaries and by river discharge. Approximate analytical solutions are constructed by means of a harmonic truncation and a perturbation expansion in a small parameter, being the ratio of tidal amplitude and depth. The net water transport results from an imposed river discharge and from residual water transport generated by nonlinear tidal rectification. Two new drivers are identified that contribute to the net water transport in tidal estuarine networks, viz. the generation of residual water transport due to gradients in dynamic pressure and due to a coupling between the tidally averaged and quarter diurnal currents through the quadratic bottom stress. The model is applied in a case study on the Yangtze Estuary, to investigate tides and division of net water transport over its multiple channels during the wet and dry season, as well as before and after the construction of the Deepwater Navigation Channel. Model results agree fairly well with observations. Process analysis reveals that the decrease in tides from dry to wet season is due to enhanced bottom stress generated by river-tide interactions. Also, the seasonal variations in net water transport are explained. It is furthermore shown and explained that due to the Deepwater Navigation Channel tidal currents have increased and net water transport has decreased in the North Passage. These changes have profound implications for net sediment transport and salinity intrusion.

  20. Probability Distribution of Precipitation Extremes over the Yangtze River Basin%1960-2005年长江流域降水极值概率分布特征

    Institute of Scientific and Technical Information of China (English)

    苏布达; Marco Gemmer; 姜彤

    2008-01-01

    Based on the daily observational precipitation data of 147 stations in the Yangtze River basin for 1960-2005,and the projected daily data of 79 grids from ECHAM5/MPI-OM in the 20th century,time series of precipitation extremes which contain annual maximum(AM)and Munger index(MI)were constructed.The distribution feature of precipitation extremes was analyzed based on the two index series.Research results show that(1)the intensity and probability of extreme heavy precipitation are higher in the middle Mintuo River sub-catchment,the Dongting Lake area,the mid-lower main stream section of the Yangtze River,and the southeastern Poyang Lake sub-catchment;whereas,the intensity and probability of drought events are higher in the mid-lower Jinsha River sub-catchment and the Jialing River sub-catchment;(2)compared with observational data,the averaged value of AM is higher but the deviation coefficient is lower in projected data,and the center of precipitation extremes moves northwards;(3)in spite of certain differences in the spatial distributions of observed and projected precipitation extremes,by applying General Extreme Value(GEV)and Wakeby(WAK)models with the method of L-Moment Estimator(LME)to the precipitation extremes,it is proved that WAK can simulate the probability distribution of precipitation extremes calculated from both observed and projected data quite well.The WAK could be an important function for estimating the precipitation extreme events in the Yangtze River basin under future climatic scenarios.