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Sample records for changjiang yangtze river

  1. 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.

  2. 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

  3. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  5. Observed residual currents off the Changjiang (Yangtze) River mouth in summertime of 1959 and 1982

    Institute of Scientific and Technical Information of China (English)

    朱建荣; 戚定满; 肖成猷

    2004-01-01

    Data taken in two large scale ocean observations in China in summer 1959 and 1982 were used to analyze the residual current off the Changjiang (Yangtze) River mouth. The currents at surface off the mouth in July 1959 and 1982 flow northeastward and eastward due to the river discharge, the current speed was larger in1982 than in 1959. All the bottom currents flow landward due to baroclinic effect. The surface current was controlled by the river runoff and the Taiwan Warm Current (TWC). A return current at surface off the mouth was observed in September 1959. In general, the bottom currents were controlled by the TWC in most study area in addition to the runoff near the mouth. Although driven by 3-D model with the monthly averaged forces (river discharge, wind stress, baroclinic effect, open boundary water volume flux and tidal mixing) in August, the simulated circulations were basically consistent with the observed ones with episodic time manner.

  6. Benthic nutrient fluxes in the intertidal flat within the Changjiang (Yangtze River) Estuary

    Institute of Scientific and Technical Information of China (English)

    GAO Lei; LI Daoji; WANG Yanming; YU Lihua; KONG Dingjiang; LI Mei; LI Yun; FANG Tao

    2008-01-01

    In an annual cycle from March 2005 to February 2006, benthic nutrient fluxes were measured monthly in the Dongtan intertidal flat within the Changjiang (Yangtze River) Estuary. Except for NH4+, there always showed high fluxes from overlying water into sediment for other four nutrients. Sediments in the high and middle marshes, covered with halophyte and consisting of macrofauna, demonstrated more capabilities of assimilating nutrients from overlying water than the low marsh. Sampling seasons and nutrient concentrations in the overlying water could both exert significant effects on these fluxes. Additionally, according to the model provided by previous study, denitrification rates, that utilizing NO3- transported from overlying water (DW) in Dongtan sediments, were estimated to be from -16 to 193 μmol·h-1·m-2 with an average value of 63 μmol·h-1·m-2 (n=18). These estimated values are still underestimates of the in-situ rates owing to the lack of consideration of DN, I.e., denitrification supported by the local NO3- production via nitrification.

  7. 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.

  8. Fish assemblage structure in the hypoxic zone in the Changjiang (Yangtze River) estuary and its adjacent waters

    Science.gov (United States)

    Shan, Xiujuan; Jin, Xianshi; Yuan, Wei

    2010-05-01

    Fish assemblage structure in the hypoxic zone in the Changjiang (Yangtze River) estuary and its adjacent waters were analyzed based on data from bottom trawl surveys conducted on the R/V Beidou in June, August and October 2006. Four fish assemblages were identified in each survey using two-way indicator species analysis (TWIA). High fish biomass was found in the northern part, central part and coastal waters of the survey area; in contrast, high fish diversity was found in the southern part of the survey area and the Changjiang estuary outer waters. Therefore, it is difficult to maintain high fishery production when high fish diversity is evenly distributed in the fish community. Fish became smaller and fish size spectra tended to be narrower because of fish species variations and differences in growth characteristics. Fish diversity increased, the age to maturity was reduced and some migrant species were not collected in the surveys. Fish with low economic value, small size, simple age structure and low tropic level were predominant in fish assemblages in the Changjiang estuary and its adjacent waters. The lowest hypoxic value decreased in the Changjiang estuary and its adjacent waters.

  9. Decreasing Reference Evapotranspiration in a Warming Climate——A Case of Changjiang (Yangtze) River Catchment During 1970-2000

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This study deals with temporal trends in the Penman-Monteith reference evapotranspiration estimated from standard meteorological observations, observed pan evaporation, and four related meteorological variables during 1970-2000 in the Yangtze River catchment. Relative contributions of the four meteorological variables to changes in the reference evapotranspiration are quantified. The results show that both the reference evapotranspiration and the pan evaporation have significant decreasing trends in the upper, the middle as well as in the whole Changjiang (Yangtze) River catchment at the 5% significance level, while the air temperature shows a significant increasing trend. The decreasing trend detected in the reference evapotranspiration can be attributed to the significant decreasing trends in the net radiation and the wind speed.

  10. 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.

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

    Directory of Open Access Journals (Sweden)

    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.

  12. 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.

  13. 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.

  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. The environment effect on fish assemblage structure in waters adjacent to the Changjiang (Yangtze) River estuary (1998-2001)

    Institute of Scientific and Technical Information of China (English)

    YU Haicheng; XIAN Weiwei

    2009-01-01

    We collected fish abundance data in the Changjiang (Yangtze River) estuary and adjacent waters in November 1998, May 1999, November 2000, and May 2001. Using the data, we evaluated the characteristics of the fish assemblages at each site and investigated the effect of several environmental factors. We used a multivariate analysis, including community ordination methods such as detrended correspondence analysis (DCA) and canonical correspondence analysis (CCA), and two-way indicator species analysis (TWINSPAN). We analyzed the biological community structure and environmental factors to determine their spatial distributions, temporal dynamics, and seasonal variations. Among the fish species, five exceeded 5% of the total abundance: Harpodon nehereus (42.82%), Benthosema pterotum (13.85%), Setipinna taty (11.64%), Thryssa kammalensis (9.17%) and Apogonichthys lineatus (6.49%). These were separated into four ecological assemblages: hypsithermal-saline, hypsithermal-brackish, hypothermal-brackish, and hypothermal-saline. We evaluated the degree of influence of environmental factors on the fish community. Our analyses suggested that environmental factors including water depth, salinity, turbidity, transparency, nutrient, and suspended matter formed a synthetic spatial gradient between the coastal and pelagic areas. Ecological and environmental factors changed temporally from 1998 to 2001, and drove the fish community succession. The environmental factors driving the fish community structure included bottom temperature, water depth, bottom and surface pH, surface total phosphorous, and bottom dissolved oxygen. This investigation was completed before completion of the Three Gorges Dam; therefore the results of this study provide an important foundation for evaluating the influence of the human activities.

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

    Science.gov (United States)

    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. Heavy metal enrichments in the Changjiang (Yangtze River) catchment and on the inner shelf of the East China Sea over the last 150 years.

    Science.gov (United States)

    Guo, Yanwei; Yang, Shouye

    2016-02-01

    Compositions of heavy metals including Cu, Zn, Cr and Pb in three sediment cores recovered from the lower basin of the Changjiang (Yangtze River) and the inner shelf mud of the East China Sea were analyzed by traditional X-ray florescence (XRF) and XRF Core Scanner. This study aims to investigate the accumulation of heavy metals in the fluvial sediments and to decipher the influence of anthropogenic activities within the large catchment over the last 150 years. The data suggest that the heavy metals, especially Pb and Zn, show obvious enrichments in concentrations since 1950s, and the small and consistent variations of heavy metal concentrations before 1950s can represent geochemical background values. After removing the grain size effect on elemental concentrations, we infer that the sources of heavy metals predominantly come from natural weathering detritus, while human contamination has increased over the last half century. The calculations of both enrichment factor and geoaccumulation index, however, indicate that the pollution of these heavy metals in the fluvial and shelf environments is not significant. The rapid increase in human activities and fast socioeconomic development in the Changjiang catchment and East China over the last five decades accounts for the enrichments of heavy metals in the river and marine sediments. The inner shelf of the East China Sea, as the major sink of the Changjiang-derived fine sediments, provides a high-resolution sediment archive for tracing the anthropogenic impacts on the catchment.

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

    Energy Technology Data Exchange (ETDEWEB)

    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)

  20. 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

  1. Human impacts on the Changjiang (Yangtze) River basin, China, with special reference to the impacts on the dry season water discharges into the sea

    Science.gov (United States)

    Chen, Xiqing; Zong, Yongqiang; Zhang, Erfeng; Xu, Jiangang; Li, Shijie

    2001-11-01

    The annual mean discharge from the upper Changjiang (Yangtze) basin has shown a significant decreasing trend since the end of the 19th century. Since the 1970s, the monthly mean discharge to the sea has also shown a dramatic decrease during dry seasons. This paper examines the human impacts on the major hydrological processes in the Changjiang River basin, with a special focus on their influence on the discharge from the drainage basin to the sea during the dry season. Climatic warming has been obvious since the 1960s in the headwater area, resulting a continuous retreat of glaciers, while the increased evaporation is responsible for the dropping of lake water levels and decrease in water area. Such a trend continuing into the coming decades will significantly change the seasonal hydrological processes, especially the dry-season discharges from the upper basin. The decreasing vegetation cover and the increasing reservoir volume capacity also impacted on the water discharge over the past decades, although in different ways. The possible impacts of the Three Gorges Dam on the monthly variation of water discharge to the sea are discussed with special emphasis. In the middle basin discussions are focused on the effect of decreasing lake area, of increasing reservoir capacity, and of irrigated agriculture on the temporal changes of water discharge since the 1950s. The human impacts on water discharge from the lower basin to the sea are mostly attributed to water transfer to both tributary and neighboring drainage basins by a large number of electric pumping stations and sluices. The total water transferring capacity is more than 5000 m 3/s along the lower river. Studies indicate that in a dry season the water discharge to the sea is greatly reduced and results in strong saltwater intrusion in the estuary.

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

    Science.gov (United States)

    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.

  3. 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.

  4. 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".

  5. 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.

  6. Historical evolution of hypoxia in the East China Sea off the Changjiang (Yangtze River) estuary for the last ~13,000 years: Evidence from the benthic foraminiferal community

    Science.gov (United States)

    Wang, Feifei; Liu, Jian; Qiu, Jiandong; Wang, Hong

    2014-11-01

    The records of benthic foraminifera and lithology of a 35.60-m-long core in the East China Sea off the Changjiang (Yangtze River) estuary were used to decipher the paleoenvironmental changes over the last 13,000 years. The result suggests three stages of environmental evolution: a littoral environment dominated by tide influence in the period of Younger Dryas (YD) (about 13,000-11,500 cal yr BP), a nearshore to shallow-sea environment in the early-mid Holocene (11,500-4600 cal yr BP), and a shallow-sea environment with significant hypoxia since the last 4600 years. The alternation of the low-oxygen foraminiferal assemblages (LOFA) and oxic foraminiferal assemblages (OFA) suggests a weakening hypoxia condition during 4600-2000 cal yr BP, which may be linked to factors such as the weakening of Taiwan Warm Current (TWC), a stronger East Asian Summer Monsoon (EASM), a moderate water depth with stable sea-level and sufficient supply of terrigenous organic materials. Together with the above mentioned factors, human activities might explain the low-oxygen conditions over the past 400 years. However, the hypoxic process was discontinued during the period of 0.6-0.4 cal ka BP, possibly due to the cold climate during Little Ice Age (LIA), which weakened EASM and reduced Total Solar Irradiance (TSI). This study confirms that the species of Epistominella naraensis, Bolivina spp., Bulimina marginata and Ammonia convexidorsa could be used as indicators for hypoxia while the Quinqueloculina spp. as a sensitive indicator of bottom oxygen levels at the core site.

  7. 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.

  8. 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.

  9. Geomorphologic Study of Anhui Section of Changjiang River Using Landsat TM Image

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Fluvial landforms in the Anhui section of the Changjiang (Yangtze) River are often considered as the main factors for frequent floods. It is these special landforms that influence the channel changes of the Changjiang River.Using Landsat TM image of 2000, this paper conducted a series of image processing, including principal component analysis, multi-spectral composition, gray value statstics, and spectral analysis of ground objects. Then it got a new interpretation map of different kinds of fluvial landforms of the Changjiang River in the Anhui section. Based on the interpretation mentioned above, the paper analyzes the distribution and characteristics of such typical landforms as terraces, floodplains and battures, and their functions on the changes of river channel. The results show a consistence with the earlier conclusion that the Anhui section of the Changjiang River tends to deflect gradually toward south,which provides more implications for further study on the geomorphologic evolution of the river channel.

  10. 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.

  11. Concentrations and fluxes of uranium in two major Chinese rivers: The Changjiang River and the Huanghe River

    Science.gov (United States)

    Zhou, Jing; Du, Jinzhou; Moore, Willard S.; Qu, Jianguo; Zhang, Guiling

    2015-01-01

    We collected samples from January 2010 to December 2011 to determine the concentrations and fluxes of uranium in the Changjiang (Yangtze) and Huanghe (Yellow) Rivers in China. The dissolved U concentrations (DUC) were measured by inductively coupled plasma mass spectrometry (ICP-MS) at the freshwater end members of the Changjiang and Huanghe Rivers. The DUCs ranged from 1.32 to 4.06 nmol/L and 13.85 to 29.99 nmol/L in the Changjiang and Huanghe Rivers, respectively. The temporal variations of DUC followed the seasonal change, with high values in the two rivers occurring during the dry seasons and low values during the flood seasons. A strong negative correlation was observed between DUC and discharge in the Changjiang River (R2 = 0.69), but a weak correlation (R2 = 0.35) was found in the Huanghe River. The correlations between the major ions and the U in the rivers indicated that the primary source of uranium was from the weathering of carbonate and evaporite in the Changjiang Basin. The weathering of evaporite-bearing sequences and the erosion of loess dominated the U sources of the Huanghe River. Carbonate ligands in the dry season and phosphate ligands in the wet season were the primary factors controlling the accumulation and transportation of dissolved uranium in the Changjiang River. The soils of the Huanghe Basin contained five times more leachable uranium compared to the soils of the Changjiang Basin, which may explain the high DUC in the Huanghe River. The weighted-mean-concentrations of uranium were 2.78 nmol/L in the Changjiang River and 22.07 nmol/L in the Huanghe River. This lead to annual dissolved U fluxes (DUF) of 2.3 × 106 mol/yr in the Changjiang River and 4.1 × 105 mol/yr in the Huanghe River. The sum of the U fluxes in the two rivers represented 11.9% of the global U riverine flux into the sea comparing with 2.5% of the global runoff into the sea. The 234U/238U activity ratio of the Huanghe River had higher values (1.455-1.418) compared to the

  12. 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.

  13. 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

  14. 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.

  15. 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.)

  16. Taizhou Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Taizhou Bridge lies between Taizhou, Zhenjiang and Changzhou City in Jiangsu Province. The total length of Taizhou Bridge is 62.088 kin. The whole line is designed by freeway codes with six lanes in two directions. The wholeinvestment is 9.37 billion RMB and the planned construction duration is 5.5 years. The main bridge crossing the Yangtze River is a continuous three-pylon two-span suspension bridge with the main span of 1 080 m. The bridge system is realized for the first time and ranks first in the world until now.

  17. 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.

  18. CHEMICAL WEATHERING PROCESSES AND ATMOSPHERIC CO2 CONSUMPTION OF HUANGHE RIVER AND CHANGJIANG RIVER BASINS

    Institute of Scientific and Technical Information of China (English)

    LI Jing-ying; ZHANG Jing

    2005-01-01

    Rock weathering plays an important role in studying the long-term carbon cycles and global climaticchange. According to the statistics analysis, the Huanghe (Yellow) River water chemistry was mainly controlled byevaporite and carbonate weathering, which were responsible for over 90% of total dissolved ions. As compared withthe Huanghe River basin, dissolved load of the Changjiang (Yangtze) River was mainly originated from the carbonate dissolution.The chemical weathering rates were estimated to be 39.29t/(km2·a)and 61.58t/(km2·a)by deduting the HCO3- derived from atmosphere in the Huanghe River and Changjiang River watersheds, respectively. The CO2 con-sumption rates by rock weathering were calculated to be 120.84 × 103mol/km2 and 452.46 × 103mol/km2 annually in thetwo basins, respectively. The total CO2 consumption of the two basins amounted to 918.51 × 109mol/a, accounting for3.83% of the world gross. In contrast to other world watersheds, the stronger evaporite reaction and infirm silicateweathering can explain such feature that CO2 consumption rates were lower than a global average, suggesting that thesequential weathering may be go on in the two Chinese drainage basins.

  19. 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.

  20. 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.

  1. A new record of Cleantioides emarginata Kwon & Kim,1992 (Crustacea, Isopoda, Valvifera) from Changjiang River estuary, China

    Institute of Scientific and Technical Information of China (English)

    LIU Wenliang; Gary C.B.POORE

    2013-01-01

    At present,descriptions of Cleantioides emarginata Kwon & Kim,1992 have been limited to the type locality of Pusan,Korea.In this study,we discovered this species in the Changjiang (Yangtze) River estuary,China.This represents an extension of the known geographical range of C.emarginata.In addition,we present information of a colour pattern not previously described,along with details on the estuarine habitat of the species.

  2. SEDIMENT TRANSPORT IN THE YANGTZE RIVER ESTUARY

    Institute of Scientific and Technical Information of China (English)

    SHEN Zhigang

    2001-01-01

    The hydrodynamic and the sediment transport patterns within the estuary of the Yangtze River are complex because of interaction of fluvial and the tidal forces, depending on freshwater discharge and tidal range. Based on the data measured in recent years, this paper discusses the characteristics of flow and sediment movement in the Yangtze River Estuary and their influences on the evolution of the estuary.

  3. 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.

  4. 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.

  5. Trophic relationships in the Changjiang River estuarine salt marshes: preliminary investigation from δ13C and δ15N analysis

    Institute of Scientific and Technical Information of China (English)

    QUAN Weimin; HUANG Danqing; CHU Tianjiang; SHENG Qiang; FU Cuizhang; CHEN Jiakuan; WU Jihua

    2009-01-01

    To obtain information on food web structure in salt marshes of the Changjiang (Yangtze) River Estuary, the δ13C and δ15 N values of primary producers and consumers were determined. The mean δ13C values of 31 dominant consumers ranged from -23.13%c to -14.37%0. Except for several species (Eriocheir sinensis, Sinonovacula constricta and Potamocorbula ustulata), consumers had interme-diate δ13C values between those of benthic microalgae and Spartina alterniflora. The mean δ154N values of 31 dominant consumers varied between 6.87%0 and 13.33%0, which indicate three trophic levels in salt marshes of the Changjiang River Estuary. A total of 18 macroinvertebrates species and four fish species represented primary consumers with trophic levels ranging from 2.0 to 2.7. Secondary consumers included two macroinvertebrates and seven fishes with trophic levels varying between 3.0 and 3.9. The consumers were divided into three trophic guilds, i.e., detritivorous/algae feeders, omnivores and carnivores. The detrital food chain was the main energy flow pathway in the salt marsh food web of the Changjiang River Estuary, and the marsh vascular plants were at least as equally important as microphytobenthos for secondary production. The important trophic function of the salt marsh habitats in the estuary is revealed.

  6. 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.

  7. 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.”

  8. PRELIMINARY DISCUSSIONS OF BASIC CLIMATIC CHARAC- TERISTICS OF PRECIPITATION DURING RAINING SEASONS IN REGIONS SOUTH OF CHANGJIANG RIVER AND ITS RELATIONSHIP WITH SST ANOMALIES

    Institute of Scientific and Technical Information of China (English)

    陈绍东; 王谦谦; 钱永甫

    2003-01-01

    Basic climatic characteristics are analyzed concerning the precipitation anomalies in raining seasons over regions south of the Changjiang River (the Yangtze). It finds that the regions are the earliest in eastern China where raining seasons begin and end. Precipitation there tends to decrease over the past 50 years. Waters bounded by 9(S -1(S, 121(E - 129(E are the key zones of SST anomalies that affect the precipitation in these regions over May ~ July in preceding years. Long-term air-sea interactions make it possible for preceding SST anomalies to affect the general circulation that come afterwards, causing precipitation anomalies in the raining seasons in regions south of the Changjiang River in subsequent years.

  9. 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.

  10. 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.

  11. Economic Structure Transformation and Land Use Change of the Changjiang River Basin

    Institute of Scientific and Technical Information of China (English)

    WU Yingmei; SU Yufang; ZHANG Lei

    2006-01-01

    Land, as a key factor of production, is an appropriate indicator of national and regional economic structure transformation. Land use in the Changjiang (Yangtze) River Basin (CRB) since the 1950s has experienced these changes.Industrialization has been the most powerful force of the change in the regional development of the CRB. Virtually all regional resources were put into this effort to modernize the industrial production and urban construction systems of the CRB whose industrialization and urbanization has been a success story, with impressive structural change in both production and land use. These changes are evident in modern urban areas, but even more in traditionally rural areas. The regression analysis of regional development in the CRB over an extended period shows that the dominant factor in regional land use change is widespread industrialization in rural areas rather than the expansion of urban area. Thus, urbanization has had a limited influence on land use change in the CRB. A major task in realizing more sustainable land use in the future development of CRB is to relocate industrial activities from rural to urban areas.

  12. 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 (similaritymorphological methods were identified by molecular methods, especially gelatinous zooplankton and merozooplankton that were likely sampled at different life history phases. Zooplankton community structures differed significantly among all of the samples. The MOTU spatial distributions were influenced by the ecological habits of the corresponding species. In conclusion, single-gene-targeted metagenomic 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.

  13. The self-regulation process and its mechanism of channels’ bed changes in the Changjiang (Yangtze) Estuary in China

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xiaohe; LI Jiufa; ZHU Wenwu; CHENG Heqin; CHEN Wei

    2015-01-01

    Recent bathymetric changes in the Changjiang Estuary under the influence of artificial regulation engineerings and basin reservoirs have been analyzed based on the maritime charts since 1997 and recent fieldworks. The results indicate a slight erosion of the channels in the upper and middle estuary, continuing deposition and seaward move of the mouth bar crest and intensifying erosion at the nearshore seabed. It is noteworthy that the morphological evolution caused by intensive human activities dominates over the changes from nature process. First, the riverbes are eroded overall in the South Branch (SB), the South Channel (SC) and the upper and middle reaches of the North Channel (NC). The nearshore seabed outside the river mouth is being eroded slightly, which is attributed to the declining sediment supply from the Changjiang Basin due to the construction of the Three Gorges Dam upstream. The sediment above the seabed is very active and coarsened, meanwhile, sand waves are becoming more distinct. Second, a deposition occurs in the North Brach (NB), the mouth of the NC, the mouth bars of the North Passage (NP) and the South Passage (SP) and especially the main channel of the NP, where it shows a massive siltation after the deep waterway project. The reasons for the recent changes are not only the dynamic structure in estuarine mouth bars, but also the supply of sediment resuspension in a local and offshore area. Meanwhile, the severe erosion and siltation in some reaches is related to the construction of estuarine engineerings. It is indicated that the Changjiang Estuary is gradually self-adjusted and adapting to the varying natural factors and intensive human activities. The study on the mechanism of self-regulation of the recent bathymetric changes in the Changjiang Estuary has important and practical significance.

  14. An estimation on budget and control of phosphorus in the Changjiang River catchment.

    Science.gov (United States)

    Shen, Zhi-Liang; Li, Zheng; Miao, Hui

    2012-11-01

    Based on field investigations in the Changjiang River mouth, rain sampling from the river's upper reaches to the mouth, historical data, and relevant literatures, the budget and major control factors of total phosphorus (TP) and dissolved inorganic phosphorus (DIP) in the river catchment were estimated and discussed from the catchment scale. It will supply a base for effective controlling P concentration in the Changjiang River and its mouth. Results show that the export fluxes of TP and DIP were mainly controlled by the river runoff. The TP and DIP in the Changjiang River came mainly from agricultural nonpoint source P losses from fertilizer and soil and point sources of industrial waste and residential sewage discharges. The export fluxes of TP and DIP in the river mouth were only 27.0% and 28.3% of the imports from the river catchment, respectively, suggesting that most of P were removed in transportation. A mass of freshwater marshes in the river catchment were the main areas to remove P. Significant increasing in utilization of fertilizer P and incessant increasing in water and soil loss areas were the primary reasons of agricultural nonpoint source P losses. How to decrease the agricultural nonpoint source P loss from the catchment scale is a key controlling P concentration in the Changjiang River and its mouth. The point source industrial waste P discharge has been primarily treated in the river catchment, but the residential sewage P discharge needs further control.

  15. Jiangxinzhou-Emerald on the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    <正>Jiangxinzhou, green as jade and shaped like a green plum, is inlaid on the Yangtze River, in the western part of Jianye District in Nanjing, Jiangsu Province. It is only 6 kilometers away from Xinjiekou, the downtown commercial center, and is separated from the new modern city, the New District of Hexi in Nanjing, with a strip of water. The river with a distant source and long stream is just like the arms of a mother to embrace the green island of 15 kilometers and to nourish the 12,000 residents at the island.

  16. 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.

  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. Holocene depocenter shift in the middle-lower Changjiang River basins and coastal area in response to sea level change

    Institute of Scientific and Technical Information of China (English)

    Zhanghua WANG; Jingpu LIU; Baocheng ZHAO

    2008-01-01

    Authors collected 38 sedimentary boreholes and numerous seismic profiles from previous publications to delineate the Holocene sedimentation rate of six major depositional sinks in the middle-lower Changjiang River basins and its river coast.The results demonstrate that the highest sedimentation rate of ca.15 m/ka occurred in the mono-depositional sink of the former Changjiang River mouth during 10000-8000 aBP,when post-glacial transgression happened and the Changjiang water level remained at lower stand.With the rising of the Changjiang water level in response to sea level rise,Jianghan Basin of the middle Changjiang River becomes the other important depositional sink with highest sedimentation rate of 10 m/ka since 7000 aBP.As Jianghan Basin was mostly filled up at ca.4000 aBP,Dongting Basin and the lower Changjiang valley trapped sediments in great amounts like in the river mouth.A considerable amount of Changjiang sediments has been delivered,both eastward and southward,to the inner continental shelf of the East China Sea,especially after 2000 aBP.This indicates reduced sediment storage capacity of the middle-lower Changjiang valley and the river mouth.In total,ca.1307.4 billion tons of sediment have deposited in the middle-lower Changjiang floodplain since 7000 aBP.In the meantime,ca.947 billion tons of sediment have been deposited in the river coast to form the Changjiang subaqueous delta and the ZhejiangFujian along-shelf mud wedge.Our result also reveals two time stages with lower sedimentation rates(<4 m/ka) in all basins during 8000-7000 aBP and in the estuarine area during 4000-2000 aBP,probably owing to stengthened chemical weathering of decline of monsoon precipitation.

  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. Two black carbon pools transported by the Changjiang and Huanghe Rivers in China

    Science.gov (United States)

    Wang, Xuchen; Xu, Caili; Druffel, Ellen M.; Xue, Yuejun; Qi, Yuanzhi

    2016-12-01

    Major rivers play important roles in transporting large amounts of terrestrial organic matter from land to the ocean each year, and the organic matter carried by rivers contains a significant fraction of black carbon (BC). A recent study estimated that 0.027 Gt of BC is transported in the dissolved phase by rivers each year, which accounts for 10% of the global flux of dissolved organic carbon. The relative sources of this large amount of riverine dissolved black carbon (DBC) from biomass burning (young, modern 14C) and fossil fuel (old, 14C free) combustion are not known. We present radiocarbon measurements of BC in both dissolved and particulate phases transported by the Changjiang and Huanghe Rivers, the two largest rivers in China, during 2015. We show that two, distinct BC pools (young and old) were carried by the rivers. The DBC pool was much younger than the particulate BC (PBC) pool. Mass balance calculations indicate that most (78-85%) of the DBC in the Changjiang and Huanghe Rivers was derived from biomass burning, and only 15-22% was from fossil fuel combustion. In contrast, PBC from biomass burning and fossil fuel combustion were approximately equal in these two rivers. Export of PBC and DBC by the rivers are decoupled, and fluxes of PBC were 4.1 and 6.7 times higher than DBC in the Changjiang and Huanghe Rivers, respectively. The 14C age differences of the two BC pools suggest that BC derived from biomass burning and fossil fuel combustion are mobilized in different phases and on different time scales in these rivers.

  1. SUSTAINABLE RURAL LIVELIHOOD AND ECOLOGICAL SHELTER CONSTRUCTION IN UPPER REACHES OF CHANGJIANG RIVER--Case Study of Zhaotong of Yunnan Province

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Sustainable livelihood theory provides a comprehensive framework for understanding the interactions between livelihoods of peasant households and regional environment change in low-income areas. Based on field survey and 946 questionnaires from peasant household conducted in the case study area of Zhaotong, Yunnan Province, the paper has analyzed the basic characteristics of the rural livelihoods, including the asset base status, the income-generating activities, the energy consumption pattern, and the fertility behavior, in the upper reaches of the Changjiang (Yangtze)River. The micro-level findings show the conflicts among extensive agricultural development models, rural energy consumption structures heavily relying on biomass and the environment protection. The conversion of cropland to forest and grass program (CCFGP) has exerted an important influence on the livelihoods of the peasant households, but its design has given little considerations to their long-term livelihood sources, which will affect its sustainability to a great extent. From the perspective of sustainable livelihoods framework, the objectives that must be addressed in the ecological shelter construction in the upper reaches of the Changjiang River should include, first, facilitating access of peasant households to credit, technology and public services, second, encouraging the peasant households to adopt agricultural technology with environmental benefits and strengthen resources-conserving investments, and third, paying close attention to the rural energy problems and the long-term livelihood sources of the households with CCFGP. Given the weak asset base and difficulties of livelihood strategies shift, ecological shelter construction in the upper reaches of the Changjiang River will take a long time.

  2. Summer nutrients structure and phytoplankton growth under the influence of freshwater-saline water mixing in the Changjiang River Estuary

    Science.gov (United States)

    Liu, Ying; Wang, Kui; Chen, Jianfang

    2015-04-01

    The spatial distribution of NO3-, PO43-, SiO32- in summer were studied in the Changjiang (Yangtze River) Estuary and the adjacent East China Sea(ECS), the nutrients distribution was mainly controlled by the Changjiang dilution water and offshore seawater mixing. NO3-, PO43-, SiO32- were high west and low east, presenting two tongues shape nearshore. Combined with the nutrient structure difference along the estuary gradient, the potential relative nutrient limitation of surface water at each station was distinguished. Coastal water was featured with excess nitrogen, in summer DIN/P ratio was up to 160 in the frequent algae blooms area, while Si/N reached as low as 0.5, which could be caused by luxury consumption of P and Si by diatom bloom. For better understanding the process of nutrients structure variation and influence on phytoplankton growth under the Changjiang dilution water and seawater mixing, we also conducted field incubation simulating different fresh-saline water mixing scale, by 100%, 75%, 50%, 25% and 0% for about 3 days. The results were as follows: (1) The lower the percentage of freshwater, the lower the growth rate and pH increase rate of phytoplankton during the exponential growth period; (2) Macronutrients were apparently consumed. PO43- in the 100%, 75% and 50% dilution treatments were depleted within 48 h, suggesting that PO43- limit phytoplankton growth below salinity of 26. (3) For the 100% treatment the DIN/P ratio doubled as PO43- was consumed rapidly, while DIN decreased slowly. The DIN/Si ratio decreased to about 0.7 times the original level during the first 48 h, reflecting the lower initial DIN/Si value compared to the diatom uptake ratio (dDIN/dSi) during the incubation period. The incubation presented the phytoplankton growth extent and rate difference during fresh-saline water mixing, which makes nutrients gradient, and this mixing process may cause local blooms to change the nutrient structure, then might result in phytoplankton

  3. 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.

  4. 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.

  5. Applied analysis of ventilation technology in residential buildings in Changjiang river valley

    Institute of Scientific and Technical Information of China (English)

    杨露露; 卢军; 王曦; 甘灵丽

    2009-01-01

    Making the use of ventilation technology may decrease building energy consumption,improve indoor thermal environment,and ameliorate indoor air quality. Combining with the meteorological characteristics in the Changjiang river valley and focusing on Chongqing,this work makes an applied analysis of the feasibility of intermittent mechanical ventilation. By comparison of various ventilation modes,it gives a summary of the suitable ventilation ways for different weather conditions with the combination of testing data and experimental data.

  6. 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.

  7. Does reduced sediment load contribute to increased outbreaks of harmful algal blooms off the Changjiang Estuary?

    Institute of Scientific and Technical Information of China (English)

    WANG Baodong; XIN Ming; SUN Xia; WEI Qinsheng; ZHANG Xuelei

    2016-01-01

    Harmful algal blooms (HABs) have been increasingly frequent in coastal waters around the world over the last several decades. Accelerated coastal eutrophication, resulting from the increased anthropogenic loadings of nutrients, is commonly assumed to be the primary cause of this increase. However, although important, accelerated coastal eutrophication may not be the only explanation for the increasing blooms or toxic outbreaks in estuarine waters. Changes in riverine material fluxes other than nutrients, such as sediment load, may significantly affect biological activities and HAB incidence in estuarine and coastal waters. A case study off the Changjiang (Yangtze River) Estuary indicated that with the increasing riverine loadings of nutrients, the sediment load from the Changjiang River has been reduced by 70% over the past four decades. A comparison of long-term data revealed that the phytoplankton biomass maximum has expanded to a region of much lower salinity due to the drastic reduction in riverine sediment load and the subsequent improvement in light penetration in the Changjiang River plume. Furthermore, there was an apparent mirror-image relationship between the sediment load from the Changjiang River and the HAB incidence off the Changjiang Estuary over the past four decades, and the number of HAB incidents was significantly negatively correlated with the sediment load. Therefore, it is argued that the drastic decline in sediment load from the Changjiang River reduced turbidity in the Changjiang Estuary and thus contributed to the increased frequency of HABs in the buoyant discharge plumes.

  8. BED-LOAD TRANSPORT IN THE SOUTH CHANNEL OF THE CHANGJIANG ESTUARY

    Institute of Scientific and Technical Information of China (English)

    Cailan GONG; Caixing YUN; Jianjun JIN

    2002-01-01

    The bed-load movement and the evolution of the Changjiang (Yangtze) Estuary are studied by using the geographic information system and the remote sensing image processing software Analysis on the erosion and siltation of the river mouth is performed for the period 1988-2000. The possible location and thickness of the future deposition areas in the estuarine channels are predicted.

  9. 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.

  10. 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.

  11. Composition and variability in the export of biogenic silica in the Changjiang River and the effect of Three Gorges Reservoir

    NARCIS (Netherlands)

    Ran, X.; Liu, S.; Liu, J.; Zang, J.; Che, H.; Ma, Y.; Wang, Y.

    2016-01-01

    Silicon (Si) plays an essential role in biogeochemical processes, but is still poorly characterized in the river system. This study addressed the biogenic silica (BSi) composition, origin and variation in the Changjiang River, and estimated the impacts of natural processes and human activities on th

  12. Light absorption properties of CDOM in the Changjiang (Yangtze) estuarine and coastal waters: An alternative approach for DOC estimation

    Science.gov (United States)

    Yu, Xiaolong; Shen, Fang; Liu, Yangyang

    2016-11-01

    Field measurements of CDOM absorption properties and DOC concentrations were collected in the Changjiang estuarine and coastal waters from 2011 to 2013. CDOM absorption coefficient at 355 nm (ag (355)) was found to be inversely correlated with salinity, with Pearson's coefficients r of -0.901 and -0.826 for summer and winter observations, respectively. Analysis results of the relationships between salinity and CDOM optical properties (i.e., absorption coefficient and spectral slope) suggested that terrigenous inputs dominated CDOM sources in the Changjiang estuary, but the proportion of terrigenous CDOM declined with increasing salinity. The level of CDOM in the Changjiang estuary was lower compared to some of the major estuaries in the world, which could be attributed to several controlling factors such as vegetation cover in the drainage basin, the origin of recharged streams and high sediment load in the Changjiang estuary. We further evaluated the relationships between CDOM and DOC and their mixing behavior among world's major estuaries. An empirical model was finally developed to estimate DOC concentration from ag (355) and spectral slope S275-295 using a non-linear regression. This empirical relationship was calibrated using the Cal dataset, and was validated with the Val dataset, resulting in an acceptable error with the R2 of 0.746, the RMSE of 20.99 μmol/L and the rMAD of 14.46%.

  13. 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

  14. Flooding 1990s along the Yangtze River, has it concern of global warming?

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    There were a series of severe floods along the middle to lower reaches of the Yangtze River (Changjiang River) in China during the 1990s. The extensive summer (June, July and August) precipitation is mostly responsible for the flooding. The summer rainfall in the 1980s and the 1990s is much higher than that in the previous 3 decades. The means for 1990-1999 is +87.62 mm above normal, marked the 1990s the wettest decade since the 1950s. Six stations with a time span of 1880-1999 are selected to establish century-long rainfall series. This series also shows that the 1990s is the wettest decade during the last 120 years. In the wettest 12 years, four occurred in the 1990s (1991,1996,1998 and 1999). Both global and China's temperature show there is a relative lower air temperature during the 1960-1970s, and a rapid warming in the 1980-1990s. Comparisons of rainfall between 1960-1979 and 1980-1999 show there are dramatic changes. In the cold period 1960-1979, the summer rainfall along the Yangtze River is 3.8 % to 4.7 % below the normal, during the warm period 1980-1999, over 8.4 % to 18.2 % of summer rainfall occurs. Over the whole eastern China, the summer rainfall shows opposite spatial patterns from the 1960-1970s to 1980-1990s. The consistent trend toward more rainfall with global warming is also presented by the greenhouse scenario modeling. A millennial Drought/flood Index for the middle to lower reaches of the Yangtze River showed that although the surplus summer rainfall in the 1990s is the severest during the past 150 years, it is not outstanding in the context of past millennium. Power spectra of the Drought/flood Index show significant interdecadal periods at 33.3 and 11.8 years. Thus, both the natural inter-decadal variations and the global warming may play important roles in the frequent floods witnessed during the last two decades.

  15. SPATIAL DIFFERENTIATION OF LAND TRANSFER--Case Study of Shanghai, Nanjing and Taizhou in Changjiang River Delta

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The policy of land transfer has greatly influenced the macro economy of China with the commencement of another innovation of land use system. Therefore, it is urgent to put forward some rational and feasible suggestions for local government to manage the market of land transfer. Moreover, it is important in the field of study on agricultural land use change to analyze the spatial differentiation and structural specification of land transfer, which are caused by rural households' behavior. This paper selected 11 factors covering four aspects of rural households' family structure, family location, family income structure and the natural quality of land resources, all of which influence the behavior differentiation of rural households, to establish the index model indicating spatial differentiation of land transfer. Results show that the spatial differentiation of land transfer can be divided into four degrees and three categories through analyzing rural households' questionnaires from Shanghai, Nanjing and Taizhou in the Changjiang (Yangtze) River Delta. Since up to 80% of rural households belong to middle degrees, it can be concluded that the rural land market develops evenly in the study areas. And it is also indicated that the natural quality of land resources and the maximum income of rural land are most important factors influencing the spatial differentiation of land transaction. Considering different factors, the countermeasures can be carried out to enhance the spatial differentiation of land transfer so as to promote economic development and social security of rural China. All in all, both microfactors and macro-factors influencing rural households' behavior of rural land transfer should be taken into account in order to make spatial differentiation and structural specification of rural land transfer notable.

  16. Buoyancy leads to high productivity of the Changjiang diluted water: a note

    Institute of Scientific and Technical Information of China (English)

    CHEN Chen-Tung Arthur

    2008-01-01

    Being the mightiest river emptying into the East China Sea (ECS) and the Pacific Ocean,compounded with the large increase of nitrogen and phosphorus input due to anthropogenic activities,the Changjiang River (Yangtze River) has become a dominating source of these nutrients to the estuary.The high nutrient concentrations notwithstanding,however,outside of the estuary the high biological productivity of the Changjiang diluted water (CDW) are most probably fueled mainly by nutrient-rich subsurface waters originating from the upwelled Kuroshio waters.This is because while the buoyancy of the CDW spreads it out on the ECS continen-tal shelf,the CDW entrains subsurface waters along with the nutrients.Nutrients thus supplied are several times more than those supplied by the Changjiang River.

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. How to appreciate the Gardens South of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    李竹君

    2015-01-01

    The primary goal of classical Chinese garden is to provide buildings, green spaces or relaxing spaces, but it is later endowed with more functions as a carrier for showing human beings’dependence on and respect for the nature, as well as var-ious emotions of them. This article briefly discussed how to appreciate the gardens south of the Yangtze River from aspects of construction elements, artistic conception and techniques.

  2. 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.

  3. 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.

  4. 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.

  5. EARLY DEGRADATION RATE PARTICULATE ORGANIC CARBON AND PHYTOPLANKTON PIGMENTS UNDER DIFFERENT DISSOLVED OXYGEN LEVEL OFF THE CHANGJIANG (YANGTZE) RIVER ESTUARY%长江口外颗粒有机碳及光合色素在不同溶氧水平下早期降解速率研究

    Institute of Scientific and Technical Information of China (English)

    朱卓毅; 张经; 吴莹; 张莹莹; 林晶; 季倩

    2013-01-01

    Organic matter decay plays a key role in hypoxia mechanism. Studies indicate that hypoxia off the Changji-ang estuary has been deteriorating in the past a few decades, but few study has focused on the dissolved oxygen consumption rate based on in situ organic matter degradation. In this study, an organic matter degradation experiment off the Changjiang estuary was performed to shed light on the mechanism of the occurrence of hypoxia. The experiment was carried out under different dissolved oxygen (DO) levels, namely high DO (DO>95%) and low DO (DO95%) or 8.22 to 8.16 (DO0.67, Chla a: r2>0.93). Constant k for FUCO and Chi a ranged from 0.18 to 0.22 and it was slightly higher under high DO condition, indicating that pigments degrades faster under high DO condition. Based on the constant k, the half life of chlorophyll a can be calculated, which is around 3-4 days. Further, based on the reported POC/Chl a ratio, percentage of degraded phytoplankton carbon in the bulk degraded POC can be calculated. Under high DO condition, only 6%-8.5% of the bulk degraded POC was phytoplankton carbon, while under low DO condition, 20%-28% of the bulk degraded POC was phytoplankton carbon. Thus, phytoplankton tends to contribute more as an organic matter source for degradation under low DO conditions on a short time scale. According to the POC degradation rate, organic-matter-degradation-related DO consumption rate off the Changjiang estuary can then be estimated, which was 82-91 mmol/(m2d)(DO>95%)and 27-30 mmol/(m2·d)(DO<50%), respectively. The rate is much higher than reported DO flux in the deep ocean, or reported DO consumption rate in the upper 50 m layer of the South China Sea. According to the actual initial DO level of the Changjiang Estuary and adjacent area in winter, it can then further be estimated that it would take 50-150 days to develop hypoxia after stratification prevails off the Changjiang estuary. It is notable that stratification generally begins during April and

  6. 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, Pconserve these four major Chinese carps species.

  7. 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.

  8. 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.

  9. 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.

  10. Yangtze. Yangtze

    Energy Technology Data Exchange (ETDEWEB)

    Qing, Dai; Adams, P.; Thibodeau, J. [eds.

    1994-12-31

    The major criticisms regarding the construction of the world`s largest dam on the Yangtze River in China were presented. Construction of the Three Gorges dam was proposed more than 70 years ago. However, the opinions of those opposed to its construction have been repeatedly suppressed by the Chinese government. This book is a collection of documents debating the merits (or lack of merits) of the Three Gorges project. The documents represent an indictment of the political system that produced the decision to build the mega-hydroelectric power generating facility. The construction of the 185-metre-high dam across the Yangtze River is scheduled to begin in 1997; it aims to generate 18.2 million kilowatts on completion in 2009. The critiques focus on a closed decision-making process that distorts technical data and analysis to meet political needs, and justifies the dam on operational, geographical and structural reasons. Critics believe that the dam will fail to control flood damages, navigation will be impeded rather than enhanced, and the promised electricity will not materialize. The authors also make recommendations as to how flood protection, navigation and electricity could be provided more safely, more quickly and at less cost. 29 refs., 5 tabs., 5 figs.

  11. Impact of seasonal tide variation on saltwater intrusion in the Changjiang River estuary

    Institute of Scientific and Technical Information of China (English)

    QIU Cheng; ZHU Jianrong; GU Yuliang

    2012-01-01

    An improved 3-D ECOM-si model was used to study the impact of seasonal tide variation on saltwater intrusion into the Changjiang River estuary,especially at the bifurcation of the North Branch (NB) and the South Branch (SB).The study assumes that the river discharge and wind are constant.The model successfully reproduced the saltwater intrusion.During spring tide,there is water and salt spillover (WSO and SSO) from the NB into the SB,and tidally averaged (net) water and salt fluxes are 985 m3/s and 24.8 ton/s,respectively.During neap tide,the WSO disappears and its net water flux is 122 m3/s.Meanwhile,the SSO continues,with net salt flux of 1.01 ton/s,much smaller than during spring tide.Because the tidal range during spring tide is smaller in June than in March,overall saltwater intrusion is weaker in June than in March during that tidal period.However,the WSO and SSO still exist in June.Net water and salt fluxes in that month are 622 m3/s and 15.35 ton/s,respectively,decreasing by 363 m3/s and 9.45 ton/s over those in March.Because tidal range during neap tide is greater in June than in March,saltwater intrusion in June is stronger than in March during that tidal period.The WSO and SSO appear in June,with net water and salt fluxes of 280 m3/s and 8.55 ton/s,respectively,increasing by 402 m3/s and 7.54 ton/s over those in March.Saltwater intrusion in the estuary is controlled by the river discharge,semi-diurnal flood-ebb tide,semi-monthly spring or neap tide,and seasonal tide variation.

  12. 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.

  13. Particulate n-alkanes and fatty acids in the ChangJiang river system

    Institute of Scientific and Technical Information of China (English)

    WU Ying; ZHANG Jing; LIU Sumei; ZHANG Zaifeng; CHEN Hongtao; XIONG Hui

    2007-01-01

    Particulate samples were collected from the Changjiang river system during a flood period, in May 1997, and POC, stable isotope and lipids associated with particles were examined. Results showed the decrease (0.84% ~ 1.88%) of organic carbon content from the upper reaches to the estuary.δ13C values of particulate organic carbon was in the range of -24.9×10-3 to -26.6×10-3, which were close to the isotopic signature of continental C3 vegetation. Total particulate n-alkanes concentrations varied from 1.4 to 10.1μg/dm3,or from 23.7 to 107μg/g of total suspended matter. Fatty acids were present in all the samples, from 1.4 to 5.4μg/dm3, with saturated and unsaturated straight-chain and branched compounds in the carbon number range from C12 to C30. Both δ13C and the ratio of carbon content to nitrogen content indicate the predominance of terrestrial inputs (soil organic matter) among the particles. The biomarker approach has been used to identify the relative portion of terrigenous and autochthonous fraction in the particulate samples. The distribution of fatty acids suggests a striking phytoplanktonic and microbial signal in most particle samples. The terrestrial alkanes are used to estimate the contribution of terrestrial inputs along the mainstream.

  14. 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.

  15. 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.

  16. Diversity, abundance, and possible sources of fecal bacteria in the Yangtze River.

    Science.gov (United States)

    Sun, Haohao; He, Xiwei; Ye, Lin; Zhang, Xu-Xiang; Wu, Bing; Ren, Hongqiang

    2017-03-01

    The fecal bacteria in natural waters may pose serious risks on human health. Although many source tracking methods have been developed and used to determine the possible sources of the fecal pollution, little is known about the overall diversity and abundance of fecal bacterial community in natural waters. In this study, a method based on fecal bacterial sequence library was introduced to evaluate the fecal bacterial profile in the Yangtze River (Nanjing section). Our results suggested that the Yangtze River water harbors diverse fecal bacteria. Fifty-eight fecal operational taxonomic units (97% identity level) were detected in the Yangtze River water samples and the relative abundance of fecal bacteria in these samples ranged from 0.1 to 8%. It was also found that the relative abundances of the fecal bacteria in locations near to the downstream of wastewater treatment plants were obviously higher than those in other locations. However, the high abundance of fecal bacteria could decrease to the normal level in 2~4 km in the river due to degradation or dilution, and the overall fecal bacteria level changed little when the Yangtze River flew through the Nanjing City. Moreover, the fecal bacteria in the Yangtze River water were found to be highly associated (Spearman rho = 0.804, P bacteria. Collectively, the findings in this study reveal the diversity, abundance, and possible sources of fecal bacteria in the Yangtze River and advance our understandings of the fecal bacteria community in the natural waters.

  17. Terrestrial input and nutrient change reflected by sediment records of the Changjiang River Estuary in recent 80 years

    Institute of Scientific and Technical Information of China (English)

    LI Junlong; ZHENG Binghui; HU Xupeng; WANG Yiming; DING Ye; LIU Fang

    2015-01-01

    A variety of environmental problems have been observed in the Changjiang River Estuary and adjacent coastal area, including eutrophication, harmful algal blooms (HABs), and hypoxia in recent decades. Application of sedimentary biogenic element indicators on the study of paleoenvironment can reconstruct environmental evolution history of waters. Two 210Pb-dated cores were collected from the Changjiang River Estuary (S3) and adjacent coastal area (Z13), and total organic carbon (TOC), total nitrogen (TN), biogenic silicon (BSi), total phosphorus (TP) and phosphorus (P) species were analyzed. Three stages of environmental changes are deduced by the nutrient sedimentary records. First, nutrient concentration increased rapidly since the 1950s, which attributed to agriculture development and overused chemical fertilizers. Second, nutrient concentration kept high and primary production began to promote during the 1960s to 1980s, while diatom abundance and proportion began to decline since the 1970s, accompanied by reduced 23SiO − concentration and flux from the river. Third, due to several dams and bridges constructed, river runoff and coastal hydrodynamic conditions reduced to a certain extent since the 1990s, which aggravated the unbal-ance in nutrient structure. Multi-nutrient proxies in sediment can reflect the natural environm-ental changes as well as influence of human activities.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  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. 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.

  4. 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.

  5. Assessing the hydrologic alteration of the Yangtze River using the histogram matching approach

    Science.gov (United States)

    Huang, F.; Zhang, N.; Guo, L. D.; Xia, Z. Q.

    2016-08-01

    Hydrologic changes of the Yangtze River, an important river with abundant water resources in China, were investigated using the Histogram Matching Approach. Daily streamflow data spanning the time interval from 1955 to 2013 was collected from Yichang and Datong stations, which monitor the hydrologic processes of the upper and lower reach of the Yangtze River, respectively. The Gezhouba Dam, the first dam constructed at the main stream of the Yangtze River, started operations in 1981. 1981 was used to differentiate the pre-dam (1955-1980) and post-dam (1981-2013) hydrologic regimes. The hydrologic regime was quantified by the Indicators of Hydrologic Alteration. The overall alteration degree of the upper Yangtze River was 31% and the alteration degree of every hydrologic indicator ranged from 10% to 81%. Only 1, 5 and 26 hydrologic indicators were altered at high, moderate and low degrees, respectively. The overall alteration degree of the lower Yangtze River was 30%, and the alteration degree of every hydrologic indicator ranged from 8% to 49%. No high alteration degree was detected at the Datong station. Ten hydrologic indicators were altered at moderate degrees and 22 hydrologic indicators were altered at low degrees. Significant increases could be observed for the low-flow relevant indicators, including the monthly flow from January-March, the annual minimum 1, 3, 7, 30 and 90-day flows, and the base flow index.

  6. Embryotoxicity and genotoxicity evaluation of sediments from Yangtze River estuary using zebrafish (Danio rerio) embryos.

    Science.gov (United States)

    Li, Qian; Chen, Ling; Liu, Li; Wu, Lingling

    2016-03-01

    Sediments function both as a sink and a source of pollutants in aquatic ecosystems and may impose serious effects on benthic organisms and human health. As one of the largest estuaries in the world, the Yangtze River estuary suffers from abundant wastewater from the coastal cities. In this study, the zebrafish (Danio rerio) embryos were employed in the fish embryo test and a comet assay to evaluate the embryotoxicity and genotoxicity of the sediments from the Yangtze River estuary, respectively. Results showed that the sediments from the Yangtze River estuary significantly increased mortality, induced development abnormalities, and reduced hatching rate and heart rate of zebrafish embryos after 96 h of exposure. Significant genotoxicity was observed in the samples relative to the controls. Relatively low-level embryotoxicity and genotoxicity of sediments were found in the Yangtze River compared with other river systems. Toxic responses were also discussed in relation to the analyzed organic contaminants in sediments. More attention should be paid to non-priority pollutant monitoring in the Yangtze River estuary.

  7. Impact of climate change on the streamflow hydrology of the Yangtze River in China

    Science.gov (United States)

    Tuotuo River basin, the source region of the Yangtze River, is the key area, where the impact of climate change has been observed on many of the hydrological processes of this central region of the Tibetan Plateau. In this study, we examined six global climate models (GCMs) under three Respectively ...

  8. Potential Vorticity Structure and Inversion of the Cyclogenesis Over the Yangtze River and Huaihe River Valleys

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In this paper, the potential vorticity structure and inversion of the cyclogenesis over the Yangtze River and Huaihc River valleys during 21-23 June 2003 are investigated with a potential vorticity (PV) framework.The cyclogenesis is manifested by a lower-tropospheric PV anomaly over the Yangtze River and Huaihe River valleys at early stages mainly due to latent heat release, which greatly affects the evolution of the associated lower-tropospheric geopotential height and wind fields as demonstrated by piecewise PV inversion. At later stages, an upper-tropospheric PV anomaly develops, resulting in the growth of ridges over the cyclone in both the upstream and downstream, which provide a favorable background field for the low-level cyclone development. But the effect of a surface thermal anomaly always impedes the development of the cyclone to different extents during this cyclogenesis. It is further demonstrated that the position and the strength of the PV anomaly are closely related to the low-level cyclone development, and the lower-tropospheric PV anomaly seems to constitute the most significant feature, for instance, contributing about 60% to the low-level jet (LLJ).

  9. Modeling the impact of river discharge and wind on the hypoxia off Yangtze Estuary

    Science.gov (United States)

    Zheng, Jingjing; Gao, Shan; Liu, Guimei; Wang, Hui; Zhu, Xueming

    2016-12-01

    The phenomenon of low dissolved oxygen (known as hypoxia) in a coastal ocean system is closely related to a combination of anthropogenic and natural factors. Marine hypoxia occurs in the Yangtze Estuary, China, with high frequency and long persistence. It is related primarily to organic and nutrient enrichment influenced by river discharges and physical factors, such as water mixing. In this paper, a three-dimensional hydrodynamic model was coupled to a biological model to simulate and analyze the ecological system of the East China Sea. By comparing with the observation data, the model results can reasonably capture the physical and biochemical dynamics of the Yangtze Estuary. In addition, the sensitive experiments were also used to examine the role of physical forcing (river discharge, wind speed, wind direction) in controlling hypoxia in waters adjacent to the Yangtze Estuary. The results showed that the wind field and river discharge have significant impact on the hypoxia off the Yangtze Estuary. The seasonal cycle of hypoxia was relatively insensitive to synoptic variability in the river discharge, but integrated hypoxic areas were sensitive to the whole magnitude of river discharge. Increasing the river discharge was shown to increase hypoxic areas, while decreasing the river discharge tended to decrease hypoxic areas. The variations of wind speed and direction had a great impact on the integrated hypoxic areas.

  10. Fatigue damage reliability analysis for Nanjing Yangtze river bridge using structural health monitoring data

    Institute of Scientific and Technical Information of China (English)

    HE Xu-hui; CHEN Zheng-qing; YU Zhi-wu; HUANG Fang-lin

    2006-01-01

    To evaluate the fatigue damage reliability of critical members of the Nanjing Yangtze river bridge, according to the stress-number curve and Miner's rule, the corresponding expressions for calculating the structural fatigue damage reliability were derived. Fatigue damage reliability analysis of some critical members of the Nanjing Yangtze river bridge was carried out by using the strain-time histories measured by the structural health monitoring system of the bridge. The corresponding stress spectra were obtained by the real-time rain-flow counting method.Results of fatigue damage were calculated respectively by the reliability method at different reliability and compared with Miner's rule. The results show that the fatigue damage of critical members of the Nanjing Yangtze river bridge is very small due to its low live-load stress level.

  11. Evolution characteristics of the precipitation in the Yangtze River delta based on the probability density

    Institute of Scientific and Technical Information of China (English)

    Zeng Hong-Ling; Gao Xin-Quan; Zhang Wen

    2005-01-01

    In this paper the dryness/wetness (DW) grade data of the Yangtze River delta is transformed into the temporal evolution of precipitation probability (PP), and its hierarchically distributive characters are revealed. Research results show that the precipitation of the Yangtze River delta displays the interannual, interdecadal, as well as longer quasiperiodic changes than a century, and all the periods have a confidence level of more than 0.05. In the DW grade series of 530 years, although the frequency of the small probability events (SPEs) of drought/flood in each area of the Yangtze River delta is different, the frequency of the SPEs triggered by the climatic background state is yet the same. This research result fully shows the significant impact of the climatic evolution as a background state upon the occurrence of SPEs, which will be instructive in climatic prediction theory and in raising the accuracy of the climatic prediction.

  12. 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.

  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. 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.

  15. Study on effects of environmental temperature on dynamic characteristics of Taizhou Yangtze River Bridge

    Institute of Scientific and Technical Information of China (English)

    Miao Changqing; Chen Liang; Feng Zhaoxiang

    2011-01-01

    The dynamic characteristics of three-tower and two-span suspension bridge are analyzed at different global temperatures. An equivalent cable inner force method is proposed to consider temperature effects and to study the effects of environmental temperature on dynamic characteristics of Taizhou Yangtze River Bridge. The result demonstrates that the effects of temperature can not be neglected in static or dynamic analysis of Taizhou Yangtze River Bridge. The relationship between temperature and frequency is negative. The effects of temperature should be taken into account in experimental modal analysis of long-span bridges and damage identification.

  16. River discharge contribution to sea-level rise in the Yangtze River Estuary, China

    Science.gov (United States)

    Kuang, Cuiping; Chen, Wei; Gu, Jie; Su, Tsung-Chow; Song, Hongling; Ma, Yue; Dong, Zhichao

    2017-02-01

    Sea level changes in the Yangtze River Estuary (YRE) as a result of river discharge are investigated based on the monthly averaged river discharge from 1950 to 2011 at the Datong station. Quantification of the sea level contribution is made by model computed results and the sea level rates reported by the China Sea Level Bulletin (CSLB). The coastal modeling tool, MIKE21, is used to establish a depth-averaged hydrodynamic model covering the YRE and Hangzhou Bay. The model is validated with the measured data. Multi-year monthly river discharges are statistically calculated based on the monthly river discharges at Datong station from 1950 to 2011. The four characteristic discharges (frequency of 75%, 50% and 25%, and multi-year monthly) and month-averaged river discharge from 1950 to 2011 are used to study the seasonal and long-term changes of sea level. The computed sea level at the Dajishan and Lvsi stations are used to study the multi-time scale structure of periodic variation in different time scale of river discharge series. The results reveal that (1) the sea level rises as the river discharge increases, and its amplification decreases from upstream to the offshore. (2) The sea level amplification on the south coast is greater than that on the north coast. When river discharge increases by 20,000 m3/s, the sea level will increase by 0.005-0.010 m in most of Hangzhou Bay. (3) The sea level at the Dajishan station, influenced by river discharge, increased 0.178 mm/y from 1980 to 2011. Correspondingly, the sea level rose at a rate of 2.6-3.0 mm/y during the same period. These values were provided by the CSLB. The increase in sea level (1980-2011) at the Dajishan station caused by river discharge is 6.8-8.9% of the total increase in sea level. (4) The 19-20 year dominant nodal cycle of sea level at the Dajishan and Lvsi stations is in accord with 18.6 year nodal cycle of main tidal constituents on Chinese coasts. It implies that the sea-level change period on the

  17. Influence of the Changjiang River flood on Synechococcus ecology in the surface waters of the East China Sea.

    Science.gov (United States)

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

    2014-02-01

    Synechococcus spp. have been suggested as the primary component of picophytoplankton in the East China Sea (ECS). However, the influences of sudden environmental changes on Synechococcus assemblage composition have not yet been investigated. In the summer of 2010, a disastrous flood occurred in the Changjiang River basin. To improve our understanding of how this flood affected the Synechococcus ecology on the ECS surface, their assemblages and distributions have been described using two-laser flow cytometry and phylogenetic analysis of the phycocyanin operon. During the nonflooding summer of 2009, phycoerythrin-rich (PE-rich) Synechococcus thrived near the outer boundary of the Changjiang River diluted water (CDW) coverage, while phycocyanin-rich (PC-rich) Synechococcus predominated inside the turbid CDW with a transparency of flooding expanded the CDW coverage area to over half of the ECS. PE-rich cells showed a homogeneous distribution and a decline in abundance, while the spatial pattern of the PC-rich Synechococcus resembled the pattern from 2009. Based on the phycocyanin operon phylogeny, the Synechococcus in the ECS were categorized into five groups, ECS-1 to ECS-4 and ECS-PE, comprising a total of 19 operational taxonomic units. In the summer of 2009, ECS-2 dominated in the coast, and the ECS-3 and ECS-PE clades prevailed in the offshore waters. However, during the summer of 2010, ECS-4 and ECS-PE became the dominant strains. The injection of abundant anthropogenic pollutants and the enhancement of transparency within the CDW expansion area appear to be the factors needed to transiently alter the ecology of Synechococcus after flooding.

  18. Authigenic iron oxide formation in the estuarine mixing zone of the Yangtze River

    Science.gov (United States)

    Fan, D. J.; Neuser, R. D.; Sun, X. G.; Yang, Z. S.; Guo, Z. G.; Zhai, S. K.

    2008-02-01

    Estuaries are elementary geochemical fronts where river water and seawater mix. Within this mixing zone, iron and other non-conservative elements can undergo complex reactions to form new solid phases. In order to understand authigenic iron oxide formation in the Yangtze River Estuary, two onsite water-mixing sets of experiments were conducted, one by mixing variable amounts of unfiltered Yangtze River water with filtered East China Sea water of different salinity (set 1), the other by mixing variable amounts of filtered Yangtze River water with filtered East China Sea water of different salinity (set 2). In set 2, the minerals newly formed in the course of mixing were investigated by means of a scanning electron microscope fitted with an energy-dispersive X-ray analytical system. It was found that ferrihydrite and lepidocrocite were formed in these mixing experiments, coexisting in nearly equal amounts. These iron oxides appear as aggregated particles with a large grain-size range of several microns to more than 100 μm. The electrolytic properties of seawater played an important role in the formation of these authigenic iron oxides. Kaolinite and organic aggregates were also found in the experimentally mixed pre-filtered waters. Amounts of newly formed suspended matter (set 2) were one to three orders of magnitude lower than those of total suspended matter (TSM) (set 1). This implies that newly formed minerals represent only a very small proportion of TSM in the estuarine mixing zone of the Yangtze River.

  19. 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

  20. Contrasts of Atmospheric Circulation and Associated Tropical Convection between Huaihe River Valley and Yangtze River Valley Mei-yu Flooding

    Institute of Scientific and Technical Information of China (English)

    HONG Jieli; LIU Yimin

    2012-01-01

    The significant differences of atmospheric circulation between flooding in the Huaihe and Yangtze River valleys during early mei-yu (i.e.,the East Asian rainy season in June) and the related tropical convection were investigated.During the both flooding cases,although the geopotential height anomalies always exhibit equivalent barotropic structures in middle to high latitudes at middle and upper troposphere,the phase of the Rossby wave train is different over Eurasian continent.During flooding in the Huaihe River valley,only one single blocking anticyclone is located over Baikal Lake.In contrast,during flooding in the Yangtze River valley,there are two blocking anticyclones.One is over the Ural Mountains and the other is over Northeast Asia.In the lower troposphere a positive geopotential height anomaly is located at the western ridge of subtropical anticyclone over Western Pacific (SAWP) in both flooding cases,but the location of the height anomaly is much farther north and west during the Huaihe River mei-yu flooding.Furthermore,abnormal rainfall in the Huaihe River valley and the regions north of it in China is closely linked with the latent heating anomaly over the Arabian Sea and Indian peninsula.However,the rainfall in the Yangtze River valley and the regions to its south in China is strongly related to the convection over the western tropical Pacific.Numerical experiments demonstrated that the enhanced latent heating over the Arabian Sea and Indian peninsula causes water vapor convergence in the region south of Tibetan Plateau and in the Huaihe River valley extending to Japan Sea with enhanced precipitation; and vapor divergence over the Yangtze River valley and the regions to its south with deficient precipitation.While the weakened convection in the tropical West Pacific results in moisture converging over the Yangtze River and the region to its south,along with abundant rainfall.

  1. 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...

  2. Wang Jinzhen Attended the Forum on Cooperation & Development between Yangtze River Delta and Baltic Sea Region

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ On October 17,on behalf of CCPIT,Vice-Chairman Wang Jinzhen attended the opening ceremony of the 3rd Forum on Cooperation & Development between Yangtze River Delta Region of China and Baltic Sea Region of Europe,where he delivered a speech.

  3. Variations of Meiyu Indicators in the Yangtze-Huaihe River Basin during 1954-2003

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yanxia; ZHAI Panmao; QIAN Yongfu

    2005-01-01

    To better understand climate variations of Meiyu, some new indicators for the onset and retreat dates,duration, and Meiyu precipitation in the Yangtze-Huaihe River valley are objectively developed by using observed daily precipitation data from 230 stations in eastern China during 1954-2003.The rainy season onset and retreat dates in each station can be defined in terms of thresholds for rainfall intensity and persistence. Then, the onset and retreat dates of the Meiyu for the Yangtze-Huaihe River basin have been determined when more than 40% of stations reach the first rainy season thresholds in the study region.Based on the indicators of Meiyu in the Yangtze-Huaihe River basin, variations of Meiyu rainfall during 1954-2003 are analyzed. The results suggest that Meiyu rainfall in the Yangtze-Huaihe River basin has increased in recent 50 years. In addition, interannual and interdecadal variability of Meiyu is also obvious.All the indicators display a predominant period of about 3 years.

  4. 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.

  5. 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.

  6. Effect-directed analysis and mechanism-specific bioassays to assess the toxicity of sediments of the Yangtze River (China)

    OpenAIRE

    2016-01-01

    The Yangtze River has been a source of life and prosperity for the Chinese people for centuries. The river basin plays an important role for the economics of China and is habitat for a remarkable variety of aquatic species. Since 2009, the Three Gorges Dam (TGD) – located in the upper Yangtze Reaches, is operating at full capacity, with the benefits of flood control, electrical energy production, and improvement of river navigation. However, as a consequence of TGD impoundment, large amounts ...

  7. Mapping Water Vulnerability of the Yangtze River Basin: 1994-2013

    Science.gov (United States)

    Sun, Fengyun; Kuang, Wenhui; Xiang, Weining; Che, Yue

    2016-11-01

    A holistic understanding of the magnitude and long-term trend of water vulnerability is essential for making management decisions in a given river basin. Existing procedures to assess the spatiotemporal dynamic of water vulnerability in complex mega-scale river basins are inadequate; a new method named ensemble hydrologic assessment was proposed in this study, which allows collection of data and knowledge about many aspects of water resources to be synthesized in a useful way for vulnerability assessment. The objective of this study is to illustrate the practical utility of such an integrated approach in examining water vulnerability in the Yangtze River Basin. Overall, the results demonstrated that the ensemble hydrologic assessment model could largely explain the spatiotemporal evolution of water vulnerability. This paper improves understanding of the status and trends of water resources in the Yangtze River Basin.

  8. Simulation of extreme precipitation over the Yangtze River Basin using Wakeby distribution

    Science.gov (United States)

    Su, Buda; Kundzewicz, Zbigniew W.; Jiang, Tong

    2009-05-01

    Based on the daily observational precipitation data at 147 stations in the Yangtze River Basin during 1960-2005 and projected daily data of 79 grid cells from the ECHAM5/ MPI-OM model in the 20th and 21st century, time series of precipitation extremes which contain AM (Annual Maximum) and MI (Munger Index) are constructed. The distribution feature of precipitation extremes is analyzed based on the two index series. Three principal results were obtained, as stated in the sequel. (i) In the past half century, the intensity of extreme heavy precipitation and drought events was higher in the mid-lower Yangtze than in the upper Yangtze reaches. Although the ECHAM5 model still can’t capture the precipitation extremes over the Yangtze River Basin satisfactorily, spatial pattern of the observed and the simulated precipitation extremes are much similar to each other. (ii) For quantifying the characteristics of extremely high and extremely low precipitation over the Yangtze River Basin, four probability distributions are used, namely: General Extreme Value (GEV), General Pareto (GPA), General Logistic (GLO), and Wakeby (WAK). It was found that WAK can adequately describe the probability distribution of precipitation extremes calculated from both observational and projected data. (iii) Return period of precipitation extremes show spatially different changes under three greenhouse gas emission scenarios. The 50-year heavy precipitation and drought events from simulated data during 1951-2000 will become more frequent, with return period below 25 years, for the most mid-lower Yangtze region in 2001-2050. The changing character of return periods of precipitation extremes should be taken into account for the hydrological design and future water resources management.

  9. Analysis of Precipitation in the Middle and Lower Reaches of Yangtze River in the Summer of 2000-2007

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Based upon the summer (June-August) precipitation data from 30 stations in the middle and lower reaches of Yangtze River in China, the spatial and temporal distribution of summer precipitation in the Yangtze River Basin was analyzed. As was shown in the results, the distribution of summer precipitation in the middle and lower reaches of Yangtze River was mainly composed of four types: northern type (2005 and 2007), southern type (2001 and 2003), intermediate type (2000, 2004 and 2006) and integral type (200...

  10. Comparison of carbon chemistry data in the East China Sea between the 1990s and 2000s: implications for the impact of eutrophication from the Changjiang River (Invited)

    Science.gov (United States)

    Chou, W.; Gong, G.; Tseng, C.; Hung, C.

    2010-12-01

    The nutrient loads exported from the Changjiang River into the East China Sea (ECS) has increased over 10-fold since the 1960s because of anthropogenic disturbance such as intensive use of chemical fertilizers and the discharge of industrial and municipal waste waters. Elevated nutrient discharge causes eutrophication of the coastal waters, and stimulates harmful algal blooms and hypoxia events, both of which have been observed with increased frequently on the inner shelf off Changjiang River. To the best of our knowledge, there is, however, no study to date addressing the potential impacts of this eutrophication on carbonate chemistry in the ECS. In this study, we investigated the spatial distributions of dissolved inorganic carbon, pH, total alkalinity, and pCO2 in the entire ECS shelf in winter 2008, and compared the present results with previously published datasets. Results showed that pCO2 was negatively correlated with temperature for surface waters lower than 20oC in 2008, in contrast to the positive correlation found in the 1990s. Moreover, the wintertime ΔpCO2 in the inner shelf near the Changjiang River estuary has appreciably decreased since the early 1990s, suggesting a decline of CO2 sequestration capacity in this region. These changes can be explained by the seasonal overturn of enhanced summer accumulation of respired CO2 in bottom waters between the 1990s and the 2000s, which may be associated with the increased eutrophication/hypoxia in the inner shelf near the Changjiang River estuary over recent decades. Considering the high intra-seasonal and inter-annual variations in the ECS, more long-term studies are, therefore, certainly needed to unveil the fundamental relationship between the changes in the CO2 sequestration capacity and the increased eutrophication/hypoxia in the ECS.

  11. Channel morphology and its impact on flood passage, the Tianjiazhen reach of the middle Yangtze River

    Science.gov (United States)

    Shi, Yafeng; Zhang, Qiang; Chen, Zhongyuan; Jiang, Tong; Wu, Jinglu

    2007-03-01

    The Tianjiazhen reach of the middle Yangtze is about 8 km long, and characterized by a narrow river width of 650 m and local water depth of > 90 m in deep inner troughs, of which about 60 m is below the mean sea level. The troughs in the channel of such a large river are associated with regional tectonics and local lithology. The channel configuration plays a critical role in modifying the height and duration of river floods and erosion of the riverbed. The formation of the troughs in the bed of the Yangtze is considered to be controlled by sets of NW-SE-oriented neotectonic fault zones, in which some segments consist of highly folded thick Triassic limestone crossed by the Yangtze River. Several limestone hills, currently located next to the river channel, serve as nodes that create large vortices in the river, thereby accelerating downcutting on the riverbed composed of limestone highly susceptible to physical corrosion and chemical dissolution. Hydrological records indicate that the nodal hills and channel configuration at Tianjiazhen do not impact on normal flow discharges but discharges > 50,000 m 3s - 1 are slowed down for 2-3 days. Catastrophic floods are held up for even longer periods. These inevitably result in elevated flood stages upstream of prolonged duration, affecting large cities such as Wuhan and a very large number of people.

  12. 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.

  13. Detrital Zircon Ages of Hanjiang River:Constraints on Evolution of Northern Yangtze Craton, South China

    Institute of Scientific and Technical Information of China (English)

    Yang Jie; Gao Shan; Yuan Honglin; Gong Hujun; Zhang Hong; Xie Shiwen

    2007-01-01

    Clastic sedimentary rocks are natural samples of the exposed continental crust over large ideal sample for studying the formation and evolution of the northern Yangtze craton. Here we report laser ablation inductively coupled plasma mass spectrometer U-Pb ages of 122 detrital zircons from one sand sample of the Hanjiang River. The 110 concordant zircons reveal four major age groups of 768,444, 212, and 124 Ma, which well correlate with known magmatic events in the northern Yangtze craton. A minor group is present at 1 536 Ma, which is less known in the study area. Only seven zircons have ages of >1 750 Ma. Our results show that the Early Paleozoic, Late Triassic, and Early Cretaceous are important episodes of zircon growth and crustal growth/reworking in addition to the previously documented Neoproterozoic event. Our results suggest very limited exposures of Paleoproterozoic and Archean rocks in the northern parts of the Yangtze craton.

  14. Runoff Simulation of Three Gorges Area in the Upper Yangtze River during 1998 Flood Season

    Institute of Scientific and Technical Information of China (English)

    LIN Jian; Gabor BALINT; Balazs GAUZER

    2005-01-01

    The contribution of areal precipitation of the catchment from Cuntan to Yichang (Three Gorges area)to eight flood peaks of the Upper Yangtze River (the upper reaches of the Yangtze River) is diagnosed for 1998 flood season. A rainfall-runoff model is employed to simulate runoffs of this catchment. Comparison of observed and simulated runoffs shows that the rainfall-runoff model has a good capability to simulate the runoff over a large-scale river and the results describe the eight flood peaks very well Forecast results are closely associated with the sensitivity of the model to rainfall and the calibration processes. Other reasons leading to simulation errors are further discussed.

  15. 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.

  16. 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

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

    Institute of Scientific and Technical Information of China (English)

    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 telecon- nection mode which is from the northwest of India via the Tibetan Plateau to northern China. The for- mer mode is defined as the "south" teleconnection of the Asian summer monsoon, forming in the pe- riod 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 ver- tically over east Asia, while the Yangtze River Valley happens to locate in the ascending

  18. Decadal changes in bathymetry of the Yangtze River Estuary: Human impacts and potential saltwater intrusion

    Science.gov (United States)

    Wu, Shuaihu; Cheng, Heqin; Xu, Y. Jun; Li, Jiufa; Zheng, Shuwei

    2016-12-01

    This study analyzed bathymetric changes of the 77-km Yangtze River Estuary in China over the past ten years in order to understand the impacts of recent human activities on the estuary of a large alluvial river. Morphological changes were assessed by analyzing digitized bathymetric data of the estuarine channels from 2002 to 2013. Additionally, multi-beam bathymetric measurements made in 2012, 2014 and 2015 were utilized to investigate microtophographic bedforms of the lower reach of the estuary. Our results showed that the middle and upper reaches of the Yangtze River Estuary experienced substantial channel bed erosion in the past 10 years, and that the recent human activities have contributed to the change. These included the construction of a 70 km2 reservoir along the Yangtze River Estuary, the Qingcaosha Reservoir, for drinking water supply for the City of Shanghai, which has caused progressive bed erosion in the North Channel. The net volume of channel erosion in the Hengsha Passage from 2002 to 2013 was 0.86 × 108 m3. A large amount of the eroded sediment was trapped downstream, causing overall accretion in the upper reach of the North Passage. The middle and upper reaches of the South Passage also experienced intense erosion (0.45 × 108 m3) in the past ten years, while high accretion occurred in the lower reach because of the Deepening Waterway Project. The channel dredging left a large range of dredging marks and hollows in the North Passage. The increasing saltwater intrusion found in the Yangtze River Estuary may have been a consequence of either dredging or erosion, or both combined.

  19. Early Development of Four Cyprinids Native to the Yangtze River, China

    Science.gov (United States)

    Chapman, Duane C.

    2006-01-01

    Chapter 1 -- Notes on the Translation and Use of "A Study of the Early Development of Grass Carp, Black Carp, Silver Carp, and Bighead Carp in the Yangtze River, China" By Duane C. Chapman and Ning Wang Chapter 2 -- A Study of the Early Development of Grass Carp, Black Carp, Silver Carp, and Bighead Carp in the Yangtze River, China By Bolu Yi, Zhishen Liang, Zhitang Yu, Randuan Lin, and Mingjue HeTranslated by Duane C. Chapman and Ning Wang The document A Study of the Early Development of Grass Carp, Black Carp, Silver Carp, and Bighead Carp in the Yangtze River, China (Chapter 2 of this volume) was translated from the Chinese with the approval and assistance of the living authors of that study. It contains the most detailed description available, and approximately 200 drawings, of the early development of the subject fishes. Chapter 1 provides important instructions on the use of the translation, including a description of the Chinese morphometric conventions, which differ from those used by North American scientists. Chapter 1 also provides the historical context in which Chapter 2 was developed, and information on how the larvae of the subject fishes, which have invaded the Mississippi River basin, may be distinguished from other fishes present in the basin.

  20. Temporal and spatial changes of suspended sediment concentration and resuspension in the Yangtze River estuary

    Institute of Scientific and Technical Information of China (English)

    CHENShenliang; ZHANGGuoan; YANGShilun

    2003-01-01

    A detailed analysis of suspended sediment concentration (SSC) variations over a year period is presented using the data from 8 stations in the Yangtze River estuary and its adjacent waters, together with a discussion of the hydrodynamic regimes of the estuary. Spatially, the SSC from Xuliujing downwards to Hangzhou Bay increases almost constantly, and the suspended sediment in the inner estuary shows higher concentration in summer than in winter, while in the outer estuary it shows higher concentration in winter than in summer, and the magnitude is greater in the outer estuary than in the inner estuary, greater in the Hangzhou Bay than in the Yangtze River estuary. The sediments discharged by the Yangtze River into the sea are resuspended by marine dynamics included tidal currents and wind waves. Temporally, the SSC shows a pronounced neap-spring tidal cycle and seasonal variations. Furthermore, through the analysis of dynamic mechanism, it is concluded that wave and tidal current are two predominant factors of sediment resuspension and control the distribution and changes of SSC, in which tidal currents control neap-spring tidal cycles, and wind waves control seasonal variations. The ratio between river discharge and marine dynamics controls soatial distribution of SSC.

  1. 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.

  2. 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.

  3. Remote Sensing of Bidecadal Urbanization and its impact on Ecosystem Service in the Yangtze River Delta

    Science.gov (United States)

    Haas, Jan; Ban, Yifang

    2013-01-01

    The degree of urbanization and resulting effects on Ecosystem Services is investigated in the Yangtze River Delta in China within a 20 year time frame from 1990 to 2010. A Random forest classifier is used to classify the Landsat mosaic from 1990 and the HJ-1A/B mosaic dating from 2010. Urban Land Index (UI) and Urban Expansion Index (UX) are used to represent the intensity and rapidity of urbanization. Post-Classification Change Detection is then performed and Ecosystem Service value losses for the land-cover classes water, wetland, forest and cropland that transitioned to urban areas are calculated according to a valuation scheme adapted to the Chinese market. The results showed that Yangtze River Delta experienced significant urbanization during 1990 to 2010. Urban areas increased alongside a major decrease in cropland resulting in a substantial loss of 4.2 billion CNY in Ecosystem Services.

  4. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Shi Wei [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); 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); Hu Guanjiu; Hao Yingqun [State Environmental Protection Key Laboratory of Monitoring and Analysis for Organic Pollutants in Surface Water, Jiangsu Provincial Environmental Monitoring Center, Nanjing 210036 (China); Zhang Xiaowei [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Liu Hongling, E-mail: hlliu@nju.edu.c [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Wei Si [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China); Wang Xinru [Key Laboratory of Reproductive Medicine and Institute of Toxicology, Nanjing Medical University, Nanjing 210029 (China); Yu Hongxia, E-mail: hongxiayu@nju.edu.c [State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210093 (China)

    2011-02-15

    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 (T{sub 3}) equivalents (T{sub 3}-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 T{sub 3}/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 {mu}g/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 (T{sub 3}) equivalents (T{sub 3}-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.

  6. Analysis on the Circulation of the Yangtze River Estuary Based on ADCP Measurements

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    According to analysis on field data obtained by ADCP (Acoustic Doppler Current Profiler), the flow regime of the Yangtze River Estuary is studied by use of a 3-D numerical model. The flow field characteristics, under the influence of Coriolis force, saltwater intrusion and freshwater inflow and tidal current interaction, are depicted in details. The main driving forces and some important effective factors of lateral, longitudinal and horizontal circulation are also analyzed.

  7. 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.

  8. Fish utilization of a salt marsh intertidal creek in the Yangtze River estuary, China

    Science.gov (United States)

    Jin, Binsong; Fu, Cuizhang; Zhong, Junsheng; Li, Bo; Chen, Jiakuan; Wu, Jihua

    2007-07-01

    The structure and temporal variations of the fish community in salt marshes of Chinese estuaries are poorly understood. Fish utilization of a salt marsh intertidal creek in the Yangtze River estuary was studied based on quarterly sampling surveys in July and November, 2004, and February and May, 2005. Fishes were collected by consecutive day and night samplings using fyke nets during the ebbing spring tides. A total of 25,010 individuals were caught during the study. 17 families and 33 species were documented, and the most species-rich family was Gobiidae. Three species, Synechogobius ommaturus, Chelon haematocheilus and Lateolabrax maculatus together comprised 95.65% of the total catch, which were also the most important commercial fishery species in the Yangtze River estuary. The fish community was dominated by juvenile individuals of estuarine resident species. Time of year significantly affected fish use of salt marshes, but no significant effects of diel periodicity on the fish community were found except for fish sampling in July. These findings indicate that salt marshes in the Yangtze River estuary may play important nursery roles for fish community.

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

    Science.gov (United States)

    Dong, Chenyin; Zhang, Weiguo; Ma, Honglei; Feng, Huan; Lu, Honghua; Dong, Yan; Yu, Lizhong

    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 (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(-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.

  10. 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.

  11. 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.

  12. Impacts of urbanization on hydrology in the Yangtze River Delta, China.

    Science.gov (United States)

    Youpeng, Xu; Jintao, Xu; Jinjia, Ding; Ying, Chen; Yixing, Yin; Xingqi, Zhang

    2010-01-01

    The Yangtze River Delta is one of the most developed regions in China and the rapid development of urbanization have greatly influenced regional hydrology and water resources. Taking several typical urbanizing areas in the Yangtze River Delta as examples, this paper probes into the impacts of urbanization on hydrologic cycle and hydrological process with the support of RS, GIS and hydrological model. The research centers on the impacts of urbanization on precipitation, hydrological process, river networks, and water environment in some typical cities. The results show that: (1) Urban rain island effect is not evident when the process of urbanization is slow, while the differences of annual precipitation and flood season precipitation between urban and suburban areas increased to a certain extent in the booming stage of urbanization. (2) The annual runoff depth and the runoff coefficient increased with the development of urbanization, and the effect will be more notable when the urban areas expand to a certain size; (3) River network systems, especially low-grade rivers have been greatly destroyed in the process of urbanization, which increases the risk of flood and water degradation, so it is very important to protect natural river systems. Based on the results, some proposals of sustainable utilization and protection of water resources is also addressed.

  13. 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.

  14. 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.

  15. 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.

  16. Effects of Irradiation on Microbial Community Structure in the Yangtze River and Selection of Representative Microorganisms

    Science.gov (United States)

    Song, J. B.; Kuai, L. P.

    2017-01-01

    In the field of radioactive contamination, few studies were conducted on using microorganisms for biological monitoring. However, studies regard microorganisms as pollution indicator organisms are very common in the field of heavy metal and pesticide pollution. In this study, we chose the Yangtze River water as the research object, and studied the changes of species and quantity of cultivable bacteria in water samples under different irradiation by separation and purification methods. Results indicated that irradiation will cause the change of microbial community structure and the decline of their quantity; Among them, (flavobacterium) is mostly affected and (bacillus) is less affected. Finally, we found two representative microorganisms (Flavobacterium nitratireducens strain N1; Novosphingobium aquiterrae strain E-II-3) in the Yangtze Water and provided a reference for using microorganisms to monitor the radioactive pollution.

  17. 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.

  18. Behavior of different phosphorus species in suspended particulate matter in the Changjiang estuary

    Institute of Scientific and Technical Information of China (English)

    HE Huijun; Chen Hongtao; Yao Qingzhen; Qin Yanwen; MI Tiezhu; YU Zhigang

    2009-01-01

    Suspended particulate matter (SPM) collected in the Changjiang (Yangtze River) estuary in June 2006 was separated into five fractions via water elutriation: clay-very fine silt (63 μm). The SPM and fractionated particles were sequentially analyzed by a modified SEDEX sequential extraction method to obtain six species of phosphorus: exchangeable or loosely-sorbed P, organic P, Fe-bound P, authigenic P, detrital P and refractory P. The results indicated that all particulate phosphorus species except for detrital P were negatively correlated to particle size; a high detrital P content was found in coarse silt and very coarse silt. From the inside of the river mouth to the gate of the river mouth, organic P, Fe-bound P and refractory P in the suspended particles decreased and a higher amount of exchangeable P appeared around the gate of the river mouth. From the gate of the river mouth to the sea, exchangeable P and organic P in suspended particles increased distinctly. The total particulate P flux into the estuary from the Changjiang River was about 45.45×10~8 μmol/s during sampling. Of this, about 8.27×10~8 μmol/s was associated with the "truly suspended" fraction. The bio-available particulate P flux was about 13.58×10~8 μmol/s. Of this, about 4.24×10~8 μmol/s was transported by "truly suspended" particles.

  19. Analysis of Long-term Terrestrial Water Storage Variations in the Yangtze River Basin

    Science.gov (United States)

    Su, Bob; Huang, Ying; Wang, Lichun; Salama, Suhyb; Krol, Maaten; Hoekstra, Arjen; Zhou, Yunxuan; van der Velde, Rogier

    2014-05-01

    In this study, we analyze 32 years of TWS data obtained from Interim Reanalysis Data (ERA-Interim) and Noah model from Global Land Data Assimilation System (GLDAS-Noah) for the period between 1979 and 2010. The accuracy of these datasets is validated against 26 years (1979-2004) of runoff dataset from Yichang gauging station and compared to 32 years of independent precipitation data obtained from Global Precipitation Climatology Centre Full Data Reanalysis Version 6 (GPCC) and NOAA's PRECipitation REConstruction over Land (PREC/L). Spatial and temporal analysis of the TWS data shows that TWS in the Yangtze River basin is decreasing significantly since the year 1998. The driest period of the basin is noted from 2005 to 2010, especially in the middle and lower Yangtze reaches. The TWS changed abruptly into persistently high negative anomalies in the middle and lower Yangtze Reaches in 2004. From both basin and annual perspectives, 2006 is detected as the major inflection point at which the system exhibits a persistent decrease in TWS. Comparing these TWS trends to independent precipitation datasets shows that the recent decrease in TWS can mainly be attributed to a decrease in precipitation amount. Our finding is based on observation and modeling data sets and confirms previous results based on gauging station datasets. Reference: Huang, Y., Salama, M.S., Krol, M.S., van der Velde, R., Hoekstra, A.Y., Zhou, Y. and Su, Z. (2013) Analysis of long - term terrestrial water storage variations in the Yangtze River basin. In: Hydrology and earth system sciences (HESS): 17 (2013)5 pp. 1985-2000.

  20. Risk and toxicity assessments of heavy metals in sediments and fishes from the Yangtze River and Taihu Lake, China.

    Science.gov (United States)

    Fu, Jie; Hu, Xin; Tao, Xiancong; Yu, Hongxia; Zhang, Xiaowei

    2013-11-01

    Heavy metal pollution is one of the most serous environmental issues globally. To evaluate the metal pollution in Jiangsu Province of China, the total concentrations of heavy metals in sediments and fishes from the Yangtze River and Taihu Lake were analyzed. Ecological risk of sediments and human health risk of fish consumption were assessed respectively. Furthermore, toxicity of samples on expression of the stress responsive genes was evaluated using microbial live cell-array method. The results showed that the heavy metals concentrations in sediments from the Yangtze River were much higher than those in sediments from the Taihu Lake. However, the fishes from the Taihu Lake had higher concentrations of heavy metals than fishes from the Yangtze River. Ecological risk evaluation showed that the heavy metal contaminants in sediments from the Yangtze River posed higher risk of adverse ecological effects, while sediments from the study areas of Taihu Lake were relatively safe. Health risk assessment suggested that the heavy metals in fishes of both Yangtze River and Taihu Lake might have risk of adverse health effects to human. The toxicity assessment indicated that the heavy metals in these sediments and fishes showed transcriptional effects on the selected 21 stress responsive genes, which were involved in the pathways of DNA damage response, chemical stress, and perturbations of electron transport. Together, this field investigation combined with chemical analysis, risk assessment and toxicity bioassay would provide useful information on the heavy metal pollution in Jiangsu Province.

  1. 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.``

  2. FDI and the technological spillover effects: a comparative analysis on the Yangtze River Delta and the Pearl River Delta

    Institute of Scientific and Technical Information of China (English)

    CHEN Xin; ZHENG Yun

    2006-01-01

    This article calculates the technological spillover effects of foreign direct investment (FDI) in the Yangtze River Delta and the Pearl River Delta through Panel Data, and analyzes the influence on the technological spillover effects of the following factors in these two different areas: human capital, the opening up, R&D and the source of FDI. It makes the conclusion that FDI in different areas has different technological spillover effects and the local governments should make different policies accordingly so as to gain more obvious technology spillover effects.

  3. Multi-scale cyclone activity in the Changjiang River-Huaihe River valleys during spring and its relationship with rainfall anomalies

    Science.gov (United States)

    Qin, Yujing; Lu, Chuhan; Li, Liping

    2017-02-01

    Based on the recognition framework of the outermost closed contours of cyclones, an automated identification algorithm capable of identifying the multi-scale cyclones that occur during spring in the Changjiang River-Huaihe River valleys (CHV) were developed. We studied the characteristics of the multi-scale cyclone activity that affects CHV and its relationship with rainfall during spring since 1979. The results indicated that the automated identification algorithm for cyclones proposed in this paper could intuitively identify multi-scale cyclones that affect CHV. The algorithm allows for effectively describing the shape and coverage area of the closed contours around the periphery of cyclones. We found that, compared to the meso- and sub-synoptic scale cyclone activities, the synoptic-scale cyclone activity showed more intimate correlation with the overall activity intensity of multi-scale CHV cyclones during spring. However, the frequency of occurrence of sub-synoptic scale cyclones was the highest, and their effect on changes in CHV cyclone activity could not be ignored. Based on the area of impact and the depth of the cyclones, the sub-synoptic scale, synoptic scale and comprehensive cyclone intensity indices were further defined, which showed a positive correlation with rainfall in CHV during spring. Additionally, the comprehensive cyclone intensity index was a good indicator of strong rainfall events.

  4. 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.

  5. Water quality model with multiform of N/P transport and transformation in the Yangtze River Estuary

    Institute of Scientific and Technical Information of China (English)

    王彪; 卢士强; 林卫青; 杨漪帆; 王道增

    2016-01-01

    As the Yangtze River Estuary and adjacent sea have been classified as a problem area with regard to eutrophication, it is important to explore the spatial and temporal variations of nitrogen and phosphorus (N/P) nutrients in this area. Based on danish hydraulic institute (DHI)’s open platform Ecolab, a hydrodynamic and water quality model was developed for the Yangtze River Estuary, in which the transport and transformation processes of different forms of N/P nutrients were considered. Validations against measured data show that the model is overall reliable. Preliminary application of the model suggests that the model can simulate the characteristics of high phosphorus concentration area in the Yangtze River Estuary, and the high concentration area is closely related to the resuspension process of particulate phosphorus.

  6. 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.

  7. Meridional seesaw-like distribution of the Meiyu rainfall over the Changjiang-Huaihe River Valley and characteristics in the anomalous climate years

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Although Meiyu rainfall has its in-phase spatial variability over the Changjiang-Huaihe River Valley (CHRV) in most years, it is distributed in some years like a seesaw to the north and south of the Changjiang River, when the precipitation tends to be nearly normal throughout the valley, which would inevitably increase difficulties of making short-term prediction of the rainfall. For this reason, EOF analysis is made on 15 related stations' precipitation from June to July during 1951─2004, revealing that the EOF2 mode shows largely a north-south seesaw-like pattern, and thereby classifying Meiyu patterns into two types: "northern drought and southern flood (NDSF)" and "northern flood and southern drought (NFSD)". Afterwards, the authors investigated ocean-atmospheric characteristics when these two anomalous types occurred using the NCEP reanalysis (version 1) and the extended reconstructed SSTs (version 2). The results show that in the NDSF years, the low-level frontal area and moisture convergence center lie more southward, accompanied by weaker subtropical summer monsoon over East Asia, with the western Pacific subtropical high and 200 hPa South Asia High being more southward. Both the Northern and Southern Hemisphere Annular Modes are stronger than normal in preceding February; SST is higher off China during boreal winter and spring and the opposite happens in the NFSD years. Also, this seesaw-form Meiyu rainfall distribution might be affected to some degree by the previous ENSO event.

  8. [Shifting path of industrial pollution gravity centers and its driving mechanism in Pan-Yangtze River Delta].

    Science.gov (United States)

    Zhao, Hai-Xia; Jiang, Xiao-Wei; Cui, Jian-Xin

    2014-11-01

    Shifting path of industrial pollution gravity centers is the response of environmental special formation during the industry transfer process, in order to prove the responding of industrial pollution gravity centers to industry transfer in economically developed areas, this paper calculates the gravity centers of industrial wastewater, gas and solid patterns and reveals the shifting path and its driving mechanism, using the data of industrial pollution in the Pan-Yangtze River Delta from 2000 to 2010. The results show that the gravity center of the industrial waste in Pan-Yangtze River Delta shifts for sure in the last 10 years, and gravity center of solid waste shifts the maximum distance within the three wastes, which was 180.18 km, and shifting distances for waste gas and waste water were 109.51 km and 85.92 km respectively. Moreover, the gravity center of the industrial waste in Pan-Yangtze River Delta shifts westwards, and gravity centers of waste water, gas and solid shift for 0.40 degrees, 0.17 degrees and 0.03 degrees respectively. The shifting of industrial pollution gravity centers is driven by many factors. The rapid development of the heavy industry in Anhui and Jiangxi provinces results in the westward shifting of the pollutions. The optimization and adjustment of industrial structures in Yangtze River Delta region benefit to alleviating industrial pollution, and high-polluting industries shifted to Anhui and Jiangxi provinces promotes pollution gravity center shifting to west. While the development of massive clean enterprise, strong environmental management efforts and better environmental monitoring system slow the shifting trend of industrial pollution to the east in Yangtze River Delta. The study of industrial pollution gravity shift and its driving mechanism provides a new angle of view to analyze the relationship between economic development and environmental pollution, and also provides academic basis for synthetical management and control of

  9. The characteristics of Quaternary activity of faults in the sea area near the Yangtze River mouth

    Institute of Scientific and Technical Information of China (English)

    章振铨; 火恩杰; 刘昌森; 王锋

    2004-01-01

    By shallow seismic prospecting, it is showed that the faults in the sea area near the Yangtze River mouth are mainly the NE and NW-trending faults. The main activity time of fault is Pliocene to Early Pleistocene, and the latest activity is up to Middle Pleistocene. The maximum of fault is generally several tens meters with the throw decreased upward. The dislocation near the bottom of Middle Pleistocene is 12~13 m. The average vertical displacement rate is on a level of 10-3 mm/a.

  10. 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.

  11. Three Gorges Project: a project for ecological improvement and environmental protection in Yangtze River Basin%Three Gorges Project: a project for ecological improvement and environmental protection in Yangtze River Basin

    Institute of Scientific and Technical Information of China (English)

    Lu Youmei

    2011-01-01

    Seeking water and earning their livelihoods is the natural selection of human beings. Like other rivers on the earth, the Yangtze River is the birthplace of human civilization and survival. As an ecosystem, the Yangtze River Basin is evolving under the influences of natural factors and human activities. Because of soil erosion, pollution and human activities, the imbalance of secondary environment is exacerbated and the ecological environment has become more vul- nerable, so it is urgent to mitigate and prevent the ecological crisis. The practice has proved that implementation of en- gineering measures is an effective way to improve the ecological environment. The Three Gorges Project (TGP) has a flood control storage capacity of 22.15 billion m3, effectively storing the flood water upstream of Yichang, and protects 15 million people and 1.5 million hm2 farmland. Furthermore, the project can prevent or slow down the sedimentation and shrinkage of the lakes in the middle Yangtze River such as Dongting Lake; with an average annual power generation of about 90 billion kW ~ h, it can significantly reduce the emissions of harmful gas like CO2. In general, the construction of TGP is conducive to the ecological and environmental protection in the Yangtze River Basin and China, even the world.

  12. 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.

  13. Sedimentary BSi and TOC quantifies the degradation of the Changjiang Estuary, China, from river basin alteration and warming SST

    Science.gov (United States)

    Li, Maotian; Wang, Hong; Li, Yimiao; Ai, Wei; Hou, Lijun; Chen, Zhongyuan

    2016-12-01

    Environmental degradation in the Changjiang Estuary has recently become a global topic, given its proximity to Shanghai with a population >23 million. Intensification of human activities affecting the river basin is responsible for this degradation. Dam construction has cut off ca. 2/3 of the sediment flux to the sea, ca. 60% of the dissolved silicate load (DSi) has been retained in the reservoirs, while total phosphorous (TP) and total nitrogen (TN) transport to the sea are many times more than they were a few decades ago. Under such circumstances, details of the estuarine degradation remain poorly understood. This study uses sedimentary biological silicate (BSi) and total organic carbon (TOC) as environmental proxies to reveal the process-response of such degradation since the 1950s. Our results demonstrate the spatial differences of such degradation. The inner zone of the estuary used to be highly turbid, but presently has increasing diatom (BSi) and primary production (TOC), due to lower suspended sediment concentration (SSC) in relation to dam construction. In contrast, increasing riverine dissolved inorganic nitrate (DIN) and dissolved inorganic phosphorous (DIP) input (up to 2-5 times) and decreasing DSi provide a unique setting, with an excess in N and P, which catalyzes non-diatom algae in the less-turbid middle zone of the estuary. These are reflected by decreasing BSi and BSi/TOC since the 1950s, together with an increase of TOC of 20-40%. In the outer zone of the estuary, increasing DIN, DIP, and sea surface temperatures (SSTs), have resulted in the increase of diatom biomass by 15-20% and the growth of primary production by 30-60% since the 1950s. But the drastic decrease in DSi, Si/N, and Si/P depresses the ability of diatoms to develop, resulting in a reduction of 5-10% diatom proportion (BSi/TOC) since the 1930s. This study improves the understanding of the changing estuarine ecosystem in response to global change.

  14. 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.

  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. 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.

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

    Science.gov (United States)

    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. It then examined how, and to what extent, each set of demographic, economic, behavioral/cognitive and spatial factors influence carbon emissions at the household level. The average of urban household carbon emissions in the region was estimated to be 5.96 tonnes CO2 in 2010. Energy consumption, daily commuting, garbage disposal and long-distance travel accounted for 51.2%, 21.3%, 16.0% and 11.5% of the total emission, respectively. Regulating rapidly growing car-holdings of urban households, stabilizing population growth, and transiting residents’ low-carbon awareness to household behavior in energy saving and other spheres of consumption in the context of rapid population aging and the growing middle income class are suggested as critical measures for carbon mitigation among urban households in the Yangtze River Delta. PMID:25884853

  18. Effects of Spartina alterniflora invasion on soil respiration in the Yangtze River estuary, China.

    Directory of Open Access Journals (Sweden)

    Naishun Bu

    Full Text Available Many studies have found that plant invasion can enhance soil organic carbon (SOC pools, by increasing net primary production (NPP and/or decreased soil respiration. While most studies have focused on C input, little attention has been paid to plant invasion effects on soil respiration, especially in wetland ecosystems. Our study examined the effects of Spartina alterniflora invasion on soil respiration and C dynamics in the Yangtze River estuary. The estuary was originally occupied by two native plant species: Phragmites australis in the high tide zone and Scirpus mariqueter in the low tide zone. Mean soil respiration rates were 185.8 and 142.3 mg CO2 m(-2 h(-1 in S. alterniflora and P. australis stands in the high tide zone, and 159.7 and 112.0 mg CO2 m(-2 h(-1 in S. alterniflora and S. mariqueter stands in the low tide zone, respectively. Aboveground NPP (ANPP, SOC, and microbial biomass were also significantly higher in the S. alterniflora stands than in the two native plant stands. S. alterniflora invasion did not significantly change soil inorganic carbon or pH. Our results indicated that enhanced ANPP by S. alterniflora exceeded invasion-induced C loss through soil respiration. This suggests that S. alterniflora invasion into the Yangtze River estuary could strengthen the net C sink of wetlands in the context of global climate change.

  19. On temporal evolution of precipitation probability of the Yangtze River delta in the last 50 years

    Science.gov (United States)

    Feng, Guo-Lin; Dong, Wen-Jie; Li, Jing-Ping

    2004-09-01

    The monthly precipitation observational data of the Yangtze River delta are transformed into the temporal evolution of precipitation probability (PP) and its hierarchically distributive characters have been revealed in this paper. Research results show that precipitation of the Yangtze River delta displays the interannual and interdecadal characters and the periods are all significant at a confidence level of more than 0.05. The interdecadal is an important time scale, because it is on the one hand a disturbance of long period changes and on the other hand it is also the background for interannual change. The interdecadal and 3-7y oscillations have different motion laws in the data-based mechanism self-memory model (DAMSM). Meanwhile, this paper also provides a new train of thought for dynamic modelling. Because this method only involves a certain length of data series, it can be used in many fields, such as meteorology, hydrology, seismology and economy etc and thus has a bright perspective in practical applications.

  20. On temporal evolution of precipitation probability of the Yangtze River delta in the last 50 years

    Institute of Scientific and Technical Information of China (English)

    Feng Guo-Lin; Dong Wen-Jie; Li Jing-Ping

    2004-01-01

    The monthly precipitation observational data of the Yangtze River delta are transformed into the temporal evolution of precipitation probability (PP), and its hierarchically distributive characters have been revealed in this paper.Research results show that precipitation of the Yangtze River delta displays the interannual and interdecadal characters and the periods are all significant at a confidence level of more than 0.05. The interdecadM is an important time scale,because it is on the one hand a disturbance of long period changes, and on the other hand it is also the background for interannual change. The interdecadal and 3-7y oscillations have different motion laws in the data-based mechanism self-memory model (DAMSM). Meanwhile, this paper also provides a new train of thought for dynamic modelling.Because this method only involves a certain length of data series, it can be used in many fields, such as meteorology,hydrology, seismology, and economy etc, and thus has a bright perspective in practical applications.

  1. Temporal and spatial variations in magnetic properties of suspended particular matter in the Yangtze River drainage and their implications

    Science.gov (United States)

    Luo, Chao; Zheng, Yan; Zheng, Hongbo; Tada, Ryuji; Rits, Daniël S.

    2016-07-01

    As the largest river of China, the Yangtze River transports large amounts of sediments to the adjacent oceans. Provenance of these ancient marine sediments can only be deciphered when the source-to-sink process of modern sediments in the Yangtze River is fully understood. Many methods have been used to study the provenance of river sediment and an environmental magnetic method is applied in this study because of its fast, nondestructive advantages. Magnetic properties of suspended particulate matter (SPM) along the Yangtze River were measured to provide a holistic understanding about magnetic properties of sediments in this river and its controlling factors. The results indicate that the dominant magnetic mineral in SPM is magnetite, with a small contribution of hematite and goethite. Significant spatial variation was observed in most of the magnetic parameters, which primarily reflects the distribution of major geologic units along the drainage area of the river. Anthropogenic influences are also recorded in the magnetic parameters. The Three Gorges Dam results in a dramatic decrease of magnetic minerals in the downstream reaches, since its construction in 2003. In addition, small variations in magnetic properties of SPM are found along water depth, together with a clear seasonal shift at Datong station. This seasonal variation of magnetic properties of SPM is driven by variability in both hydrology and source contributions. This complicates the use of magnetic parameters for provenance studies. Magnetic properties of sediments in rivers are capable of tracing provenance areas, but caution must be taken into account.

  2. 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.

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

    Institute of Scientific and Technical Information of China (English)

    WANG DongQi; CHEN ZhenLou; SUN WeiWei; HU BeiBei; XU ShiYuan

    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 μmoI.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 concen-tration had significant negative correlation with salinity and a significant positive correlation with ni-trate (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 bot-tom sediment that diffused through sediment-water interface into the water body and then into at-mosphere through the gas-water interface. The emission flux of CH4 and N2O at river gas-water inter-face reached 778±59.8 and 236±03.6 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Levels and body distribution of polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) in freshwater fishes from the Yangtze River, China.

    Science.gov (United States)

    Xian, Qiming; Ramu, Karri; Isobe, Tomohiko; Sudaryanto, Agus; Liu, Xiaohua; Gao, Zishen; Takahashi, Shin; Yu, Hongxia; Tanabe, Shinsuke

    2008-03-01

    Polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecanes (HBCDs) were determined in muscle, liver and eggs of freshwater fishes from the lower reach of the Yangtze River, China. The present study is the first to report HBCD concentrations in the environment of China. The concentrations of PBDEs and HBCDs in muscle of freshwater fishes from the Yangtze River ranged from 18 to 1100ng/g and 12 to 330ng/g lipid weight (wt.), respectively. When compared with other regions of the world, the contamination of PBDEs in biota could be regarded as moderate, whereas contamination of HBCDs in biota was relatively high. The PBDE congener profiles in fishes of the present study were markedly different from those observed in freshwater and marine fishes from other regions of the world. In the present study, BDE-15, BDE-28 and BDE-47 were the predominant congeners in the fishes. This particular congener profile in fishes from the Yangtze River revealed that a specific commercial PBDE formulation (probably made in China) might have been used in the Yangtze River Delta region.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. The Great Spirit of Crossing the Changjiang River will Shine Forever%伟大的渡江精神永放光芒

    Institute of Scientific and Technical Information of China (English)

    夏文元

    2014-01-01

    The aim of this paper is to memorialize the 65th an-niversary of the great campaign of crossing the Changjiang River. Looking back at the gigantic and majestic momentum of the peo-ple's liberation army in the campaign, it reveals the eternal truth that the success of the campaign is that of the people and the Party's mass line.%本文旨在纪念伟大的渡江战役65周年,通过回顾人民解放军渡江大军排山倒海、气吞山河的气势,揭示了渡江战役的胜利就是人民的胜利,就是党的群众路线的胜利这一颠扑不灭的真理。

  16. 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.

  17. Applications of Coupled Explicit–Implicit Solution of SWEs for Unsteady Flow in Yangtze River

    Directory of Open Access Journals (Sweden)

    Yufei Ding

    2017-02-01

    Full Text Available In engineering practice, the unsteady flows generated from the operation of hydropower station in the upstream region could significantly change the navigation system of waterways located in the middle-lower reaches of the river. In order to study the complex propagation, convergence and superposition characteristics of unsteady flows in a long channel with flow confluence, a numerical model based on the coupling of implicit and explicit solution algorithms of Shallow Water Equations (SWEs has been applied to two large rivers in the reach of Yangtze River, China, which covers the distance from Yibin to Chongqing located upstream side of the Three Gorges Dam. The accuracy of numerical model has been validated by both the steady and unsteady flows using the prototype hydrological data. It is found that the unsteady flows show much more complex water level and discharge behaviors than the steady ones. The studied unsteady flows arising from the water regulation of two upstream hydropower stations could influence the region as far as Zhutuo hydrologic station, which is close to the city of Chongqing. Meanwhile, the computed stage–discharge rating curves at all observation stations demonstrate multi-value loop patterns because of the presence of additional water surface gradient. The present numerical model proves to be robust for simulating complex flows in very long engineering rivers up to 400 km.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. Semi-volatile organic compounds and trace elements in the Yangtze River source of drinking water.

    Science.gov (United States)

    Wu, Bing; Zhang, Xuxiang; Zhang, Xiaolin; Yasun, Aishangjiang; Zhang, Yan; Zhao, Dayong; Ford, Tim; Cheng, Shupei

    2009-08-01

    Determination of 24 semi-volatile organic compounds (SVOCs) and 24 trace elements in water samples was conducted in order to investigate the quality of the Nanjing source of drinking water taken from Yangtze River. The total concentrations of SVOCs and trace elements were in the range of 1,951-11,098 ng/l and 51,274-72,384 microg/l, respectively. No significant seasonal changes were found for the pollutants' concentrations. A primary health risk assessment was carried out to evaluate potential health effects. Risk quotients involving carcinogenic effects for benzo(a)anthracene, benzo(a)pyrene, benzo(b)fluoranthene, dibenz(a,h)anthracene, bis(2-ethylhexyl)phthalate and arsenic were >1 under the worst-case scenario. The results of this study demonstrate the importance of further studies on the environmental health effects of exposure to the source water.

  3. 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.

  4. [Removal effect of organics in Yangtze River raw water by MIEX resin pretreatment].

    Science.gov (United States)

    Liu, Cheng; Chen, Wei; Li, Lei; Sheng, Yu

    2009-06-15

    Jar-tests were used to study the removal effect of organics by MIEX pre-treatment from Yangtze River raw water, in which molecular weight, fractionation, UV scan, disinfection by-products, DOC and UV254 were used to estimate the removal effect. The results showed that organics in raw water were mainly composed of low-molecular weight and hydrophilic fraction, which accounted for above 50% of total organics. Above 35% DOC was removed by MIEX pretreatment with a dosage of 10 mL/L and contact time of 15 min, which due to the removal of low molecular weight and hydrophilic organics. The results of UV scan showed that organics which had high adsorption between 190 nm and 250 nm were significantly removed by MIEX pretreatment, while the part that had high adsorption on wavelength above 250 nm could be removed similar to coagulation alone.

  5. 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.

  6. 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

  7. Source apportionment of surface ozone in the Yangtze River Delta, China in the summer of 2013

    Science.gov (United States)

    Li, L.; An, J. Y.; Shi, Y. Y.; Zhou, M.; Yan, R. S.; Huang, C.; Wang, H. L.; Lou, S. R.; Wang, Q.; Lu, Q.; Wu, J.

    2016-11-01

    We applied ozone source apportionment technology (OSAT) with tagged tracers coupled within the Comprehensive Air Quality Model with Extensions (CAMx) to study the region and source category contribution to surface ozone in the Yangtze River Delta area in summer of 2013. Results indicate that the daytime ozone concentrations in the YRD region are influenced by emissions both locally, regionally and super-regionally. At urban Shanghai, Hangzhou and Suzhou receptors, the ozone formation is mainly VOC-limited, precursor emissions form Zhejiang province dominate their O3 concentrations. At the junction area among two provinces and Shanghai city, the ozone is usually influenced by all the three areas. The daily max O3 at the Dianshan Lake in July are contributed by Zhejiang (48.5%), Jiangsu (11.7%), Anhui (11.6%) and Shanghai (7.4%), long-range transport constitutes around 20.9%. At Chongming site, the BVOC emissions rate is higher than urban region. Regional contribution results show that Shanghai constitutes 15.6%, Jiangsu contributes 16.2% and Zhejiang accounts for 25.5% of the daily max O3. The analysis of the source category contribution to high ozone in the Yangtze River Delta region indicates that the most significant anthropogenic emission source sectors contributing to O3 pollution include industry, vehicle exhaust, although the effects vary with source sector and selected pollution episodes. Emissions of NOx and VOCs emitted from the fuel combustion of industrial boilers and kilns, together with VOCs emissions from industrial process contribute a lot to the high concentrations in urban Hangzhou, Suzhou and Shanghai. The contribution from regional elevated power plants cannot be neglected, especially to Dianshan Lake. Fugitive emissions of volatile pollution sources also have certain contribution to regional O3. These results indicate that the regional collaboration is of most importance to reduce ambient ozone pollution, particularly during high ozone episodes.

  8. Recent temperature increase recorded in an ice core in the source region of Yangtze River

    Institute of Scientific and Technical Information of China (English)

    KANG ShiChang; ZHANG YongJun; QIN DaHe; REN JiaWen; ZHANG QiangGong; Bjorn GRIGHOLM; Paul A. MAYEWSKI

    2007-01-01

    Interests on climate change in the source region of Yangtze River have been raised since it is a region with the greatest warming over the Tibetan Plateau (TP). A 70-year history of precipitation δ18O has been recovered using an ice core record retrieved in a plat portion of the firn area in the Guoqu Glacier (33°34′37.8″N, 91°10′35.32″E, 5720 m a.s.l.), Mt. Geladaindong (the source region of Yangtze River), in November, 2005. By using a significant positive relationship between ice core δ18O record and summer air temperature (July to September) from the nearby meteorological stations, a history of summer air temperature has been reconstructed for the last 70 years. Summer temperature was relatively low in 1940s and high in 1950s to the middle of 1960s. The lowest temperature occurred in the middle of 1970s.Temperature was low in 1980s and dramatically increased since 1990s, keeping the trend to the beginning of the 21st century. The warming rate recorded in the ice core with 0.5°C/10 a since 1970s is much higher that that in the central TP and the Northern Hemisphere (NH), and it becomes 1.1°C/10 a since 1990s which is also higher than these from the central TP and the NH, reflecting an accelerated warming and a more sensitive response to global warming in the high elevation region.

  9. 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.

  10. Radium Isotope Ratios as Tracers for Estimating the Influence of Changjiang Outflow Water to the Adjacent Seas

    Science.gov (United States)

    Kim, K.; Kim, S.

    2006-12-01

    In order to understand the influence of Changjiang (Yangtze River) outflow water to the adjacent seas during rainy and draught seasons, we studied the origin and mixing of surface water masses in the East China Sea and the South Sea of Korea. We used Ra-228/Ra-226 activity ratio and salinity as two conservative tracers in three end-members: Changjiang water (CW); Yellow Sea water (YSW); and Kuroshio water (KW). Radium isotopes in each 300-liter of surface water samples were extracted by passing through manganese-fiber cartridges, dissolved in hydroxylamine hydrochloride solution, coprecipitated as barium sulfate, dried and measured by gamma-ray spectroscopy. Results show that surface water of the East China Sea includes all three end-member waters during the rainy season, in the order of KW (50-80%), YSW (20-50%) and CW (5-15%). Surface water of the South Sea of Korea, however, includes a little fraction of, or almost no, CW in drought season. These are the preliminary results from an ongoing 6-year project ending in 2009 which aims to predict the influence of heavily polluted Changjiang outflow water to the adjacent seas after the completion of the gigantic Three Gorges (Sanxia) Dam.

  11. 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.

  12. Impacts of climate change on glacial water resources and hydrological cycles in the Yangtze River source region,the Qinghai-Tibetan Plateau,China:A Progress Report

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The Yangtze River Source Region has an area of 137,704 km2.Its mean annual runoff of 12.52 billion m3,which was recorded by the Chumda Hydrological Station in 1961-2000,accounts for only 0.13 percent of the Yangtze River’s total annual streamflow.The extensive rivers,lakes,wetlands,glaciers,snow fields,and permafrost of the Yangtze River Source Region,as well as the region’s vast alpine grasslands,play a critical role in storing and regulating the flow of water not only in the upper Yangtze River watershed of Qinghai,Sichuan,the Tibet Autonomous Region (TAR) (Tibet) and Yunnan,but also throughout the entire lower Yangtze River basin.Climate change has been the dominant factor in recent fluctuation in the volume of the Yangtze River Source Region’s glacier resources.The Chumda Hydrological Station on the lower Tongtian River has registered a mean annual glacial meltwater of 1.13 billion m3 for the period 1961-2000,makes up 9 percent of the total annual runoff.Glacial meltwater makes up a significant percentage of streamflow in the Yangtze River Source Region,the major rivers of the upper Yangtze River Source Region:the Togto,Dam Chu,Garchu,and Bi Chu (Bu Chu) rivers all originate at large glaciers along the Tanggula Range.Glaciers in the Yangtze River Source Region are typical continental-type glaciers with most glacial meltwater flow occurring June-August;the close correlation between June-August river flows and temperature illustrates the important role of glacial meltwater in feeding rivers.Glaciers in the source region have undergone a long period of rapid ablation beginning in 1993.Examination of flow and temperature data for the 1961-2000 period shows that the annual melting period for glacial ice,snow,and frozen ground in the Yangtze River Source Region now begins earlier because of increasing spring temperatures,resulting in the reduction of summer flood season peak runoffs;meanwhile,increased rates of glacier ablation have resulted in more uneven

  13. 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.

  14. 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.

  15. 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.

  16. Aerobic swimming performance of juvenile largemouth bronze gudgeon (Coreius guichenoti) in the Yangtze River.

    Science.gov (United States)

    Tu, Zhiying; Li, Liping; Yuan, Xi; Huang, Yingping; Johnson, David

    2012-06-01

    Largemouth bronze gudgeon (Coreius guichenoti), a fish species once abundant in the Yangtze River, has been rapidly declining in recent years. One important factor, among many, is the interruption of the free-flowing rivers by dams. To obtain data that can be applied to the design of an effective fishway for C. guichenoti and other species in the fish community, a laboratory study of juvenile C. guichenoti's swimming ability and energetics was conducted in a flume-type respirometer equipped with a high-speed video camera system to record swimming behavior. The critical swimming speed (Ucrit ), standard metabolic rate (SMR), and maximum metabolic rate (MO2,max ) were determined during steady swimming at four water temperatures (10, 15, 20, and 25°C). A power function accurately describes the relationship between oxygen consumption rate (MO2 ) and swimming speed (U) at the four temperatures. The Ucrit , SMR, MO2,max , and metabolic scope increased with increasing temperature. The relationship between cost of transport (COT) and U was characteristically inverse bell-shaped, with minimum COT at Uopt = 4.5-5.0 body lengths per second (bl sec(-1)). This investigation provides data on the swimming ability of C. guichenoti that will add to the basic science required for fishway design.

  17. 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.

  18. Net anthropogenic nitrogen inputs (NANI) into the Yangtze River basin and the relationship with riverine nitrogen export

    Science.gov (United States)

    Chen, Fei; Hou, Lijun; Liu, Min; Zheng, Yanling; Yin, Guoyu; Lin, Xianbiao; Li, Xiaofei; Zong, Haibo; Deng, Fengyu; Gao, Juan; Jiang, Xiaofen

    2016-02-01

    This study investigated net anthropogenic nitrogen inputs (NANI, including atmospheric nitrogen deposition, nitrogenous fertilizer use, net nitrogen import in food and feed, and agricultural nitrogen fixation) and the associated relationship with riverine dissolved inorganic nitrogen (DIN) export in the Yangtze River basin during the 1980-2012 period. The total NANI in the Yangtze River basin has increased by more than twofold over the past three decades (3537.0 ± 615.3 to 8176.6 ± 1442.1 kg N km-2 yr-1). The application of chemical fertilizer was the largest component of NANI in the basin (51.1%), followed by net nitrogen import in food and feed (26.0%), atmospheric nitrogen deposition (13.2%), and agricultural nitrogen fixation (9.7%). A regression analysis showed that the riverine DIN export was strongly correlated with NANI and the annual water discharge (R2 = 0.90, p export. We also forecasted future variations in NANI and riverine DIN export for the years 2013 to 2030, based on possible future changes in human activities and the climate. This work provides a quantitative understanding of NANI in the Yangtze River basin and its effects on riverine DIN export and helps to develop integrated watershed nitrogen management strategies.

  19. 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

    2015-11-25

    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.

  20. 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.

  1. 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.

  2. Recent human impacts on the morphological evolution of the Yangtze River delta foreland: A review and new perspectives

    Science.gov (United States)

    Du, Jing-Long; Yang, Shi-Lun; Feng, Huan

    2016-11-01

    This paper reviews the morphological change in the Yangtze River delta due to increasing human impacts from three major aspects. The first is the reduction of sediment supply to the ocean due to dam construction, soil conservation, and sand mining within the Yangtze River basin. The reduced sediment supply has decreased the progradation rate of the delta and triggered erosion in the front of the delta. The second impact relates to the reclamation of intertidal wetlands by human activities. Since the 1950s, approximately 1100 km2 of intertidal land has been embanked, resulting in the disappearance of salt marshes and even the entire intertidal zone along some sections of the coastline. The third change in the delta due to human interference is the construction of deep-waterway structures at the mouth bar, which has greatly modified the local hydrodynamics and morphology. Sediment accretion has increased significantly in these areas as a result of sheltering by these deep-waterway structures. This review shows that human activities have severely altered the natural balance among the hydrodynamics and sediment supply, affecting the morphological features of the Yangtze River watershed and delta. Human impacts on the morphological evolution of deltaic coasts in general are becoming an increasingly concern, and more attention should be paid to the management and mitigation of these effects.

  3. 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.

  4. Combined influence of sedimentation and vegetation on the soil carbon stocks of a coastal wetland in the Changjiang estuary

    Science.gov (United States)

    Zhang, Tianyu; Chen, Huaipu; Cao, Haobing; Ge, Zhenming; Zhang, Liquan

    2016-08-01

    Coastal wetlands play an important role in the global carbon cycle. Large quantities of sediment deposited in the Changjiang (Yangtze) estuary by the Changjiang River promote the propagation of coastal wetlands, the expansion of saltmarsh vegetation, and carbon sequestration. In this study, using the Chongming Dongtan Wetland in the Changjiang estuary as the study area, the spatial and temporal distribution of soil organic carbon (SOC) stocks and the influences of sedimentation and vegetation on the SOC stocks of the coastal wetland were examined in 2013. There was sediment accretion in the northern and middle areas of the wetland and in the Phragmites australis marsh in the southern area, and sediment erosion in the Scirpus mariqueter marsh and the bare mudflat in the southern area. More SOC accumulated in sediments of the vegetated marsh than in the bare mudflat. The total organic carbon (TOC) stocks increased in the above-ground biomass from spring to autumn and decreased in winter; in the below-ground biomass, they gradually increased from spring to winter. The TOC stocks were higher in the below-ground biomass than in the above-ground biomass in the P. australis and Spartina alterniflora marshes, but were lower in the below-ground biomass in S. mariqueter marsh. Stocks of SOC showed temporal variation and increased gradually in all transects from spring to winter. The SOC stocks tended to decrease from the high marsh down to the bare mudflat along the three transects in the order: P. australis marsh > S. alterniflora marsh > S. mariqueter marsh > bare mudflat. The SOC stocks of the same vegetation type were higher in the northern and middle transects than in the southern transect. These results suggest that interactions between sedimentation and vegetation regulate the SOC stocks in the coastal wetland in the Changjiang estuary.

  5. Ground-based radar reflectivity mosaic of mei-yu precipitation systems over the Yangtze River-Huaihe River basins

    Science.gov (United States)

    Luo, Yali; Qian, Weimiao; Gong, Yu; Wang, Hongyan; Zhang, Da-Lin

    2016-11-01

    The 3D radar reflectivity produced by a mosaic software system, with measurements from 29 operational weather radars in the Yangtze River-Huaihe River Basins (YRHRB) during the mei-yu season of 2007, is compared to coincident TRMM PR observations in order to evaluate the value of the ground-based radar reflectivity mosaic in characterizing the 3D structures of mei-yu precipitation. Results show reasonable agreement in the composite radar reflectivity between the two datasets, with a correlation coefficient of 0.8 and a mean bias of -1 dB. The radar mosaic data at constant altitudes are reasonably consistent with the TRMM PR observations in the height range of 2-5 km, revealing essentially the same spatial distribution of radar echo and nearly identical histograms of reflectivity. However, at altitudes above 5 km, the mosaic data overestimate reflectivity and have slower decreasing rates with height compared to the TRMM PR observations. The areas of convective and stratiform precipitation, based on the mosaic reflectivity distribution at 3-km altitude, are highly correlated with the corresponding regions in the TRMM products, with correlation coefficients of 0.92 and 0.97 and mean relative differences of -7.9% and -2.5%, respectively. Finally, the usefulness of the mosaic reflectivity at 3-km altitude at 6-min intervals is illustrated using a mesoscale convective system that occurred over the YRHRB.

  6. Distribution Regularity of Debris Flow and Its Hazard in Upper Reaches of Yangtze River and Other Rivers of Southwestern China

    Institute of Scientific and Technical Information of China (English)

    WEI Fangqiang; JIANG Yuhong; GUI Peng; DING Mingtao

    2007-01-01

    In the upper reaches of Yangtze River and other rivers of southwestern China, the debris flows develop and lead to most serious disasters because of the various landforms, complex geological structures and abundant rainfall. The distribution of debris flows has regularity in the regions with different landform, geological structure, and precipitation. The regularities of distribution of debris flows are as following:① distributed in transition belts of different morphologic regions; ②distributed in the area with strong stream trenching; ③distributed along fracture zones and seismic belts: ④distributed in the area with abundant precipitation;⑤ distribution of debris flow is azonal. The activity of abundant debris flows not only brings harm to Towns, Villages and Farmlands, Main Lines of Communication, Water-Power Engineering, Stream Channels etc., but also induces strong water and soil loss. According to the present status of debris flow prevention, the problems in disasters mitigation and soil conservancy are found out, and the key works are brought up for the future disasters prevention and soil conservancy.

  7. Dynamic biogeochemical controls on river pCO2 and recent changes under aggravating river impoundment: An example of the subtropical Yangtze River

    Science.gov (United States)

    Liu, Shaoda; Lu, Xi Xi; Xia, Xinghui; Zhang, Shurong; Ran, Lishan; Yang, Xiankun; Liu, Ting

    2016-06-01

    This paper highlights two aspects of the dynamic biogeochemical controls of riverine pCO2 in an increasingly impounded large subtropical river (the Yangtze): the terrestrial dominance through internal respiration of land-derived organic carbon and the influence of increased autotrophic activity in impounded areas on river pCO2. River pCO2 and total organic carbon (TOC) increase downstream on the main stem (pCO2: 528-1703 µatm; TOC: 137-263 µmol/L) and vary significantly among tributaries (464-3300 µatm; TOC: 109-340 µmol/L). pCO2 displays larger spatial variability than temporal variability and is spatially correlated with river organic carbon across the river (p 60%) do occur in impounded areas (especially in nutrient-rich rivers), but the decrease is mostly temporal and regional (~8% of the data points are significantly influenced, all from the upper reach and/or major tributaries). The paper concludes that terrestrial influence still dominates the pCO2 biogeochemistry in this increasingly intercepted and regulated river system.

  8. Spatio-temporal changes of NDVI and its relation with climatic variables in the source regions of the Yangtze and Yellow rivers

    Institute of Scientific and Technical Information of China (English)

    YANG Zhaoping; GAO Jixi; ZHOU Caiping; SHI Peili; ZHAO Lin; SHEN Wenshou; OUYANG Hua

    2011-01-01

    The source regions of the Yangtze and Yellow rivers are important water conservation areas of China.In recent years,ecological deterioration trend of the source regions caused by global climate change and unreasonable resource development increased gradually.In this paper,the spatial distribution and dynamic change of vegetation cover in the source regions of the Yangtze and Yellow rivers are analyzed in recent 10 years based on 1-km resolution multi-temporal SPOTVGT-DN data from 1998 to 2007.Meanwhile,the correlation relationships between air temperature,precipitation,shallow ground temperature and NDVl,which is 3×3 pixel at the center of Wudaoliang,Tuotuohe,Qumalai,Maduo,and Dari meteorological stations were analyzed.The results show that the NDVI values in these two source regions are increasing in recent 10 years.Spatial distribution of NDVl which was consistent with hydrothermal condition decreased from southeast to northwest of the source regions.NDVl with a value over 0.54 was mainly distributed in the southeastern source region of the Yellow River,and most NDVI values in the northwestern source region of the Yangtze River were less than 0.22.Spatial changing trend of NDVI has great difference and most parts in the source regions of the Yangtze and Yellow rivers witnessed indistinct change.The regions with marked increasing trend were mainly distributed on the south side of the Tongtian River,some part of Keqianqu,Tongtian,Chumaer,and Tuotuo rivers in the source region of the Yangtze River and Xingsuhai,and southern Dari county in the source region of the Yellow River.The regions with very marked increasing tendency were mainly distributed on the south side of Tongtian Rriver and sporadically distributed in hinterland of the source region of the Yangtze River.The north side of Tangula Range in the source region of the Yangtze River and Dari and Maduo counties in the source region of the Yellow River were areas in which NDVI changed with marked decreasing

  9. 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.

  10. Biodegradation potential of polycyclic aromatic hydrocarbons by bacteria strains enriched from Yangtze River sediments.

    Science.gov (United States)

    Xu, Xiaoyi; Chen, Xi; Su, Pan; Fang, Fang; Hu, Bibo

    2016-01-01

    Microbial degradation is an effective method for the removal of polycyclic aromatic hydrocarbons (PAHs) compounds from polluted sediments. Surface sediments collected from Yangtze River in the downtown area of Chongqing were found to contain PAH concentrations to various different degrees. Two bacteria strains (termed PJ1 and PJ2) isolated from the sediment samples could use phenanthrene (Phe) and fluoranthene (Flu) as carbon sources for growth thereby degrading these two PAH compounds. Using 16S rDNA gene sequencing, the isolates were identified as Sphingomonas sp. and Klebsiella sp., respectively. Biodegradation assays showed that the PJ1 presented an efficient degradation capability compared to PJ2 in cultures with the initial Phe and Flu concentrations ranging from 20 to 200 mg/L. The highest rates of Phe and Flu biodegradation by PJ1 reached 74.32% and 58.18% after incubation for 15 and 30 days, respectively. This is the first report on the biodegradation potential of the bacterial from surface sediments of an industrial area upstream of the Gorge Reservoir.

  11. The inhabited environment, infrastructure development and advanced urbanization in China’s Yangtze River Delta Region

    Science.gov (United States)

    Zhu, Xiaoqing; Gao, Weijun; Zhou, Nan; Kammen, Daniel M.; Wu, Yiqun; Zhang, Yao; Chen, Wei

    2016-12-01

    This paper analyzes the relationship among the inhabited environment, infrastructure development and environmental impacts in China’s heavily urbanized Yangtze River Delta region. Using primary human environment data for the period 2006-2014, we examine factors affecting the inhabited environment and infrastructure development: urban population, GDP, built-up area, energy consumption, waste emission, transportation, real estate and urban greenery. Then we empirically investigate the impact of advanced urbanization with consideration of cities’ differences. Results from this study show that the growth rate of the inhabited environment and infrastructure development is strongly influenced by regional development structure, functional orientations, traffic network and urban size and form. The effect of advanced urbanization is more significant in large and mid-size cities than huge and mega cities. Energy consumption, waste emission and real estate in large and mid-size cities developed at an unprecedented rate with the rapid increase of economy. However, urban development of huge and mega cities gradually tended to be saturated. The transition development in these cities improved the inhabited environment and ecological protection instead of the urban construction simply. To maintain a sustainable advanced urbanization process, policy implications included urban sprawl control polices, ecological development mechanisms and reforming the economic structure for huge and mega cities, and construct major cross-regional infrastructure, enhance the carrying capacity and improvement of energy efficiency and structure for large and mid-size cities.

  12. Affecting factors of preferential flow in the forest of the Three Gorges area, Yangtze River

    Institute of Scientific and Technical Information of China (English)

    CHENG Jinhua; ZHANG Hongjiang; HE Fan; QI Shenglin; SUN Yanhong; ZHANG Youyan; SHI Yuhu

    2007-01-01

    In order to study the factors affecting preferential flow,a 2.9 m-long,2.6 m-deep soil profile was dug in the Quxi watershed,Yangtze River.To analyze the influence of rainfall on preferential flow,the preferential flow process was observed when the rainfalls were recorded.Soil physical and infiltration characteristics were also measured to study their effect on preferential flow.The results showed that the rainfall amount that could cause preferential flow was over 26 mm.There are four types of rainfall in the Three Gorges area,namely gradually dropping rain,even rain,sudden rain and peak rain.Preferential flow process was found to be relevant to the rainfall process.It was determined that with different rainfall types,preferential flow appeared at different times,occurring first in peak rain,followed by sudden rain,gradually dropping rain,and then even rain.Preferential flow would appear when the rainfall intensity was over 0.075 mm/min.In the studied area,the coarse soil particles increased with the soil depth,and for the deeper soil layer,the coarse particles promote the formation of preferential flow.Preferential flow accelerates the steady infiltration rate in the 83-110 cm soil horizon,and the quickly moving water in this horizon also enhanced the further formation and development of preferential flow.

  13. 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.

  14. 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.

  15. [Modeling Study of A Typical Summer Ozone Pollution Event over Yangtze River Delta].

    Science.gov (United States)

    Zhang, Liang; Zhu, Bin; Gao, Jin-hui; Kang, Han-qing; Yang, Peng; Wang, Hong-lei; Li, Yue-e; Shao, Ping

    2015-11-01

    WRF/Chem model was used to analyze the temporal and spatial distribution characteristics and physical and chemical mechanism of a typical summer ozone pollution event over Yangtze River Delta (YRD). The result showed that the model was capable of reproducing the temporal and spatial distribution and evolution characteristics of the typical summer ozone pollution event over YRD. The YRD region was mainly affected by the subtropical high-pressure control, and the weather conditions of sunshine, high temperature and small wind were favorable for the formation of photochemical pollution on August 10-18, 2013. The results of simulation showed that the spatial and temporal distribution of O3 was obviously affected by the meteorological fields, geographic location, regional transport and chemical formation over YRD. The sensitivity experiment showed that the O3 concentration affected by maritime airstream was low in Shanghai, but the impact of Shanghai emissions on the spatial and temporal distribution of O3 concentration over YRD was significant; The main contribution of the high concentration of O3 in Nanjing surface was chemical generation ( alkene and aromatic) and the vertical transport from high-altitude O3, whereas the main contribution of the high concentration of O3 in Hangzhou and Suzhou was physics process. The influence of the 15:00 peak concentration of O3 over YRD was very obvious when O3 precursor was reduced at the maximum O3 formation rate (11-13 h).

  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. Evolution mechanisms of the intraseasonal oscillation associated with the Yangtze River Basin flood in 1998

    Institute of Scientific and Technical Information of China (English)

    CHEN Guixing; LI Weibiao; YUAN Zhuojian; WEN Zhiping

    2005-01-01

    With 1998 NCEP reanalysis data and the linear diagnostic equation for local meridional circulation, four main processes and the boundary effects with relatively large contributions to the intraseasonal oscillation of the vertical branches of the East Asian meridional circulation are quantitatively identified among all the processes involved in the quasi-primitive equations used in the derivation of the linear diagnostic equation. The numerical results show that the main processes with maximal contributions in the lower latitudes include the latent heating and vertical transports of sensible heat. These processes are mainly associated with the tropical convective activities and result in the low-frequency cyclones in the lower latitudes. The main processes with maximal contributions in the higher latitudes are the horizontal transports of westerly momentum and horizontal temperature advections. These processes are mainly associated with the fluctuations in the westerlies and result in the low-frequency cyclones in the higher latitudes. The low-frequency cyclones propagating away from lower latitudes not only interact with those from higher latitudes to enhance the lifting of the moist air in the Yangtze River Basin (YRB), but also leave room for the development of the low-frequency anticyclones over the South China Sea (SCS). The southwesterly in the northwestern quadrant of the SCS anticyclones provides the YRB with abundant moisture. This favorable moisture condition along with the enhanced rising motion in the YRB leads to the extraordinary flood in 1998.

  18. POPs accumulated in fish and benthos bodies taken from Yangtze River in Jiangsu area.

    Science.gov (United States)

    Hu, Guanjiu; Sun, Cheng; Li, Juan; Zhao, Yonggang; Wang, Hui; Li, Yiqiang

    2009-08-01

    The persistent organic pollutants of DDTs, PCBs, PAHs and HCHs accumulated in the bodies of fish and benthos taken at seven sites were measured to understand the issue of ecological health of Yangtze River at Jiangsu section. The highest levels for DDTs, the total 20 PCBs, the total 16 PAHs and HCHs in fish bodies were 0.076 microg/kg, 23.1 microg/kg, 7.44 ng/kg and 0.028 microg/kg, respectively and that in benthos bodies were 0.082 microg/kg, 14.3 microg/kg, 21.1 ng/kg and 0.026 microg/kg. The PAHs concentrations in benthos were higher than that in fish and they had a significant positive correlation (P < 0.05). Among the detectable chemicals, DDTs were 100% of p,p'-DDE isomers, the main PCBs were 4- and 5-chlorinated biphenyls in which PCB 105 had the highest detection frequency and the main PAHs were the compounds of 2-4 rings. PCBs were accumulated in fish bodies which enrichment factors were as high as 508-42,414 folds occurred at three sites. The results demonstrated that the accumulation measurements can be used to test the effects of PAHs, DDTs, PCBs and HCHs on aquatic ecological health.

  19. 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.

  20. Regional contribution to PM1 pollution during winter haze in Yangtze River Delta, China.

    Science.gov (United States)

    Tang, Lili; Yu, Hongxia; Ding, Aijun; Zhang, Yunjiang; Qin, Wei; Wang, Zhuang; Chen, Wentai; Hua, Yan; Yang, Xiaoxiao

    2016-01-15

    To quantify regional sources contributing to submicron particulate matter (PM1) pollution in haze episodes, on-line measurements combining two modeling methods, namely, positive matrix factorization (PMF) and backward Lagrangian particle dispersion modeling (LPDM), were conducted for the period of one month in urban Nanjing, a city located in the western part of Yangtze River Delta (YRD) region of China. Several multi-day haze episodes were observed in December 2013. Long-range transport of biomass burning from the southwestern YRD region largely contributed to PM1 pollution with more than 25% of total organics mass in a lasting heavy haze. The LPDM analysis indicates that regional transport is a main source contributing to secondary low-volatility production. The high-potential source regions of secondary low-volatility production are mainly located in areas to the northeast of the city. High aerosol pollution was mainly contributed by regional transport associated with northeastern air masses. Such regional transport on average accounts for 46% of total NR-PM1 with sulfate and aged low-volatility organics being the largest fractions (>65%).

  1. 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.

  2. 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.

  3. 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

    2016-03-11

    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.

  4. Differences between dynamics factors for interannual and decadal variations of rainfall over the Yangtze River valley during flood seasons

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The rainfall over the Yangtze River valley during flood seasons (June to July) shows both interannual and decadal variations. The rainfall has been increasing since 1990, showing a decadal signal. The variations of rainfall are influenced by the multi-scale interactions in the atmosphere-ocean coupled climate system. The rainfall, SST, and circulation are analyzed with the Chinese 160 station data, and other observational/reanalysis data, respectively. The separation between the interannual and decadal variations is carried out. The key areas affecting the Yangtze rainfall are the western Pacific warm pool on the interannual time scale and the EINO3 area on the decadal time scale, respectively. The circulation anomaly associated with the interannual variation occurs in the upper troposphere whereas that associated with the decadal variation appears in the lower troposphere.

  5. Diversity of microbial plankton across the Three Gorges Dam of the Yangtze River, China

    Directory of Open Access Journals (Sweden)

    Shang Wang

    2012-05-01

    Full Text Available The Three Gorges Dam (TGD of the Yangtze River, China, is one of the largest irrigation and hydroelectric engineering projects in the world. The effects of huge man-made projects like TGD on fauna and macrophyte are obvious, mainly through changes of water dynamics and flow pattern; however, it is less clear how microorganisms respond to such changes. This research was aimed to examine differences in microbial diversity at different seasons and locations (in front of and behind the TGD. In addition, differences between particle-attached and free-living communities were also examined. The community structures of total and potentially active microorganisms in the water columns behind and in front of the TGD were analyzed with the DNA- and RNA-based 16S rRNA gene phylogenetic approaches over three different seasons. Clone libraries of 16S rRNA genes were prepared after amplification from extracted DNA and, for some samples, after preparing cDNA from extracted rRNA. Differences were observed between sites at different seasons and between free-living and particle-attached communities. Both bacterial and archaeal communities were more diverse in summer than in winter, due to higher nutrient levels and warmer temperature in summer than in winter. Particle-attached microorganisms were more diverse than free-living communities, possibly because of higher nutrient levels and heterogeneous geochemical micro-environments in particles. Spatial variations in bacterial community structure were observed, i.e., the water reservoir behind the TGD (upstream hosted more diverse bacterial populations than in front of the dam (downstream, because of diverse sources of sediments and waters from upstream to the reservoir. These results have important implications for our understanding of responses of microbial communities to environmental changes in river ecosystems affected by dam construction.

  6. Ship Emission Inventories in Estuary of the Yangtze River Using Terrestrial AIS Data

    Directory of Open Access Journals (Sweden)

    Xin Yao

    2016-12-01

    Full Text Available Estuary forms a transition zone between inland river and open sea. In China, the estuary of the Yangtze River plays a vital role in connecting the inland and oversea shipping, and witnesses heavy vessel traffic in the recent decades. Nowadays, more attentions have been directed to the issue of ship pollution in busy waterways. In order to investigate the ship emission inventory, this paper presents an Automatic Identification System(AIS based method. AIS data is the realistic data of vessel traffic including dynamic information (position, speed, course, etc. and static information (ship type, dimensions, name, etc.. According to ship dimensions, the power of engines is estimated for different ship types. By using AIS based bottom-up approach, ship emission inventories and shares of air pollutants and GHGs (Greenhouse gases are developed. Spatial distribution of ship emissions is illustrated in the form of heat map. As a case study, the emission inventories are analyzed using AIS data of 2010 in the estuary, and following results are made:(1 shares of the emission are cruise ships 6.59%, bulk carriers 5.16%, container ships 52.96%, tankers 15.16%, fishing ships 9.16%, other ships 10.97%; (2 CO2 is the dominant part of the emission. (3 Areas of highest emission intensity are generally clustered around the South Channel, the North Channel and ports in the vicinity. The proposed method is promising because it is derived from the AIS data which contains not only real data of individual ship but also vessel traffic situation in the study area. It can server as a reference for other researchers and policy makers working in this field.

  7. 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.

  8. [Nutrient Exchange Between Meixi River and Yangtze River Due to the Typical Interaction Process of the Three Gorges Reservoir and Its Tributary].

    Science.gov (United States)

    Cao, Man; Fu, Jia-nan; Zhou, Zi-ran; Deng, Bing; Wang, Yu-chun; Wang, Fu-shun

    2015-04-01

    Frequent algal blooms have been observed in the Meixi bay of the Three Gorges Reservoirs (TGR) since its initial filling. In order to understand the effects of intrusions from Changjiang mainstream on the nutrient supply of the Meixi Bay, a detailed field monitoring was conducted from August 2012 to July 2013. The results showed that there were significant intrusions from the mainstream to the Meixi Bay during the different water level scheduling periods of the TGR. As a result, the invading flow from the mainstream of the Changjiang caused a significant effect on the nutrient distribution in the Meixi River. Annually, the mainstream transportednet fluxes of 5 478.02 t DIN, 234.04 t DIP and 5 935.22 t DSi to the Meixi Bay, which were 2.37 times, 4.32 times and 1.33 times of the corresponding fluxes from the upstream, respectively. The influence on the nutrient distributions was not only limited in the estuary area but also in the upper reaches, the supply of DIP changed the nutrient structure and relieved the P restrictions on phytoplankton growth.

  9. 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.

  10. [Effects of macro-jellyfish abundance dynamics on fishery resource structure in the Yangtze River estuary and its adjacent waters].

    Science.gov (United States)

    Shan, Xiu-Juan; Zhuang, Zhi-Meng; Jin, Xian-Shi; Dai, Fang-Qun

    2011-12-01

    Based on the bottom trawl survey data in May 2007 and May and June 2008, this paper analyzed the effects of the abundance dynamics of macro-jellyfish on the species composition, distribution, and abundance of fishery resource in the Yangtze River estuary and its adjacent waters. From May 2007 to June 2008, the average catch per haul and the top catch per haul of macro-jellyfish increased, up to 222.2 kg x h(-1) and 1800 kg x h(-1) in June 2008, respectively. The macro-jellyfish were mainly distributed in the areas around 50 m isobath, and not beyond 100 m isobath where was the joint front of the coastal waters of East China Sea, Yangtze River runoff, and Taiwan Warm Current. The main distribution area of macro-jellyfish in June migrated northward, as compared with that in May, and the highest catches of macro-jellyfish in May 2007 and May 2008 were found in the same sampling station (122.5 degrees E, 28.5 degrees N). In the sampling stations with higher abundance of macro-jellyfish, the fishery abundance was low, and the fishery species also changed greatly, mainly composed by small-sized species (Trachurus japonicus, Harpadon nehereus, and Acropoma japonicum) and pelagic species (Psenopsis anomala, Octopus variabilis) and Trichiurus japonicus, and P. anomala accounted for 23.7% of the total catch in June 2008. Larimichthys polyactis also occupied higher proportion of the total catch in sampling stations with higher macro-jellyfish abundance, but the demersal species Lophius litulon was not found, and a few crustaceans were collected. This study showed that macro-jellyfish had definite negative effects on the fishery community structure and abundance in the Yangtze River estuary fishery ecosystem, and further, changed the energy flow patterns of the ecosystem through cascading trophic interactions. Therefore, macro-jellyfish was strongly suggested to be an independent ecological group when the corresponding fishery management measures were considered.

  11. Carrying capacity for shorebirds during migratory seasons at the Jiuduansha Wetland, Yangtze River Estuary, China

    Institute of Scientific and Technical Information of China (English)

    Zhenming GE; Xiao ZHOU; Wenyu SHI; Tianhou WANG

    2008-01-01

    The carrying capacity of food resources for migrating shorebirds was estimated at a stopover site in the Yangtze River Estuary during the two migratory sea-sons (spring and autumn). From March to May and September to November 2005, the macrobenthos resources of the Jiuduansha Wetland were investigated, and most of the macrobenthos species in the newly-formed shoal were found to be appropriate food for shorebirds. Biomass measurements showed that the total food resource was about 4541.20 kg AFDW (Ash-Free Dry Weight) in spring and about 2279.64 kg AFDW in autumn. Calculations were also done in the available habi-tats (intertidal bare mudflat and Scirpus x mariqueter/ Scirpus triqueter zones) for the shorebirds. The food resources in the available areas were about 3429.03 kg AFDW in spring and about 1700.92 kg AFDW in autumn. Based on the classification (by lean weight, basic metabolic rate and body length) of the shorebird community, and using the energy depletion model, it was theorized that all of the food resources in the Jiuduansha Wetland could support about 3.5 million shorebirds during spring season and 1.75 million shorebirds during autumn season. The shorebird carrying capacities in terms of the available food were about 2.6 million and 1.3 million birds during the two respective migration seasons. Considering the effect of intake rate, the potential carrying capacity was about 0.13-0.26 million shorebirds in the study area. The main factor restricting use of the area by shorebirds was the scarcity of available habitats for roosting at high tide rather than availability of food supply. We recommend restoring some wading pools in the dense Phragmites australis and Spartina alterniflora zones for shorebirds to roost in, to improve shorebirds' utilization efficiency of the resources in the Jiuduansha Wetland.

  12. 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.

  13. 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.

  14. Impact of Climate Change on Drought in the Upstream Yangtze River Region

    Directory of Open Access Journals (Sweden)

    Guihua Lu

    2016-12-01

    Full Text Available Based on Coupled Model Intercomparison Project Phase 5 (CMIP5 dataset and a variable infiltration capacity (VIC hydrological model, this study assesses the possible influence of climate change in the upstream region of the Yangtze River on droughts in the future 30 years. Long-term daily soil moisture content were simulated by VIC model at a 50 km × 50 km resolution from 1951 to 2013. Regional historical drought events were then recognized based on soil moisture anomaly percentage index and validated with field data. Five relatively independent representative global circulation models were selected and the outputs of them were downscaled temporally and spatially as the inputs of VIC model for daily soil moisture content simulations both in the period of 1971–2000 for the present-day climate and in the period of 2021–2050 for the future. The results show that the projected annual mean temperature is likely to increase from 1.4 °C to 1.8 °C. The projected change in mean annual precipitation could be increased slightly by 0.6% to 1.3%, but the trend of precipitation change in summer and autumn might be opposite of that. Comparing the drought characteristics values recognized in 1971–2000, seven to eight additional regional drought events are likely to happen in 2021–2050. Drought duration and drought intensity are also likely to extend for 18 d to 25 d and increase by 1.2% to 6.2%, respectively. But, drought area could decrease slightly by 1.3% to 2.7% on average. These changes in drought characteristics values suggest that regional drought could become more severely prolonged and frequent in future.

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

    Science.gov (United States)

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

    2015-12-22

    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.

  16. FBG application in bridge health monitoring system of Wuhan Yangtze River 2nd Bridge

    Science.gov (United States)

    Liu, Jun

    2009-10-01

    For the traditional resistance strain sensor's shortage,for example,their stability,durability and monitoring scorpe could not satisfied the requirement of bridge monitoring system,put forward to adopt advanced fiber-optic bragg grating sensor and its technology to build up the bridge health monitoring system.Analysed the application scope and aim of difference kinds of fiber bragg grating sensors used, including stress strain sensors,temperature sensors,crack sensors and testing force ring sensors.According to the key construction sections as the project designed,expatiated their specific installation methods and construction craftwork in Wuhan Yangtze River 2th bridge.It formed distributed fiber sensing network of bridge with large-scale located fiber-optic bragg grating sensors, and pointed out the becareful prodeeding when to link no more than twenty sensors to one fiber for the demodulator precision.Discussed how to construct the data acquisition system and its function via the sensors and their demodulator.One fiber of the linked sensors connected to one channel of the demodulator and all together reached sixteen channels.The demodulator were connected to the switch through rj45 interface and communicated with the acquisition server.Designed the software program of data acquisition software system and the database,which used the Sqlite of the embed database to storage the configure information and receive the data through the TCP/IP protocol.It has been build a bridge health monitoring system base on fiber bragg grating technology.

  17. 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.

  18. 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.

  19. Source Apportionment of Volatile Organic Compounds in an Urban Environment at the Yangtze River Delta, China.

    Science.gov (United States)

    An, Junlin; Wang, Junxiu; Zhang, Yuxin; Zhu, Bin

    2017-04-01

    Volatile organic compounds (VOCs) were collected continuously during June-August 2013 and December 2013-February 2014 at an urban site in Nanjing in the Yangtze River Delta. The positive matrix factorization receptor model was used to analyse the sources of VOCs in different seasons. Eight and seven sources were identified in summer and winter, respectively. In summer and winter, the dominant sources of VOCs were vehicular emissions, liquefied petroleum gas/natural gas (LPG/NG) usage, solvent usage, biomass/biofuel burning, and industrial production. In summer, vehicular emissions made the most significant contribution to ambient VOCs (38%), followed by LPG/NG usage (20%), solvent usage (19%), biomass/biofuel burning (13%), and industrial production (10%). In winter, LPG/NG usage accounted for 36% of ambient VOCs, whereas vehicular emissions, biomass/biofuel burning, industrial production and solvent usage contributed 30, 18, 9, and 6%, respectively. The contribution of LPG/NG usage in winter was approximately four times that in summer, whereas the contribution from biomass/biofuel burning in winter was more than twice that in summer. The sources related to vehicular emissions and LPG/NG usages were important. Using conditional probability function analysis, the VOC sources were mainly associated with easterly, northeasterly and southeasterly directions, pointing towards the major expressway and industrial area. Using the propylene-equivalent method, paint and varnish (23%) was the highest source of VOCs in summer and biomass/biofuel burning (36%) in winter. Using the ozone formation potential method, the most important source was biomass/biofuel burning (32% in summer and 47% in winter). The result suggests that the biomass/biofuel burning and paint and varnish play important roles in controlling ozone chemical formation in Nanjing.

  20. 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.

  1. 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.

  2. 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.

  3. 2D NUMERICAL SIMULATION OF FLOOD AND FLUVIAL PROCESS IN THE MEANDERING AND ISLAND-BRAIDED MIDDLE YANGTZE RIVER

    Institute of Scientific and Technical Information of China (English)

    Yong-jun LU; Zhao-yin WANG; Li-qin ZUO; Li-jun ZHU

    2005-01-01

    The characteristics of water flow and sediment transport in a typical meandering and island-braided reach of the middle Yangtze River is investigated using a two-dimensional (2D)mathematical model. The major problems studied in the paper include the carrying capacity for suspended load, the incipient velocity and transport formula of non-uniform sediment, the thickness of the mixed layer on the riverbed, and the partitioning of bed load and suspended load. The model parameters are calibrated using extensive field data. Water surface profiles, distribution of flow velocities, riverbed deformation are verified with site measurements. The model is applied to a meandering and island-braided section of the Wakouzi-Majiazui reach in the middle Yangtze River,which is about 200 km downstream from the Three Gorges Dam, to study the training scheme of the navigation channels. The model predicts the processes of sediment deposition and river bed erosion,changes of flow stage and navigation conditions for the first 20 years of impoundment of the Three Gorges Project.

  4. 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.

  5. Design of Non-Navigable Span Bridges of Hutong Changjiang River Bridge%沪通长江大桥非通航孔桥设计

    Institute of Scientific and Technical Information of China (English)

    梅新咏; 侯健; 刘琳杰

    2015-01-01

    沪通长江大桥设计通行4线铁路、6车道高速公路,其非通航孔桥为简支钢桁梁结构 ,桥梁跨度112 m ,全长2 912 m ,其中跨南岸大堤桥梁3跨共336 m、跨北岸大堤桥梁2跨共224 m、跨水中横港沙区段桥梁21跨共2 352 m.非通航孔桥主桁为三片钢主桁结构 ,上层公路桥面由钢纵横梁与混凝土桥面板结合而成 ,下层铁路桥面由下弦各节点处的钢横梁与混凝土槽形梁结合而成.桥墩采用钻孔灌注桩基础 ,墩身采用单箱三室的空心钢筋混凝土结构.%The Hutong Changjiang River Bridge is designed to carry 4-track railways and 6-lane expressways .The non-navigable span bridges of the bridge are the simply-supported steel truss girder structures with span length of 112 m .The bridges are totally 2 912 m long ,of which the part of the bridges to cross the river dyke on the south bank has 3 spans and is 336 m long ,to cross the river dyke on the north bank has 2 spans and is 224 m long and to cross the section of the Henggang Islet in the river has 21 spans and is 2 352 m long .T he main trusses of the bridges are the three steel main truss structures .The upper highway decks are the structures composited by the steel stringers ,steel cross beams and concrete deck slabs while the lower railway decks are the ones composited by the steel cross beams at the panel points at the lower chords and the concrete channel girders .T he foundations for the piers of the bridges are all the bored piles and the pier shafts are the reinforced concrete three-cell single-box hollow structures .

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

    Directory of Open Access Journals (Sweden)

    B. L. Zhuang

    2015-06-01

    Full Text Available Absorbing aerosols can significantly modulate shortwave solar radiation in the atmosphere, affecting regional and global climate. Aerosol absorption coefficient (AAC is an indicator to assess the impact of absorbing aerosols on radiative forcing. In this study, the near-surface AAC and absorption angstrom exponent (AAE in urban Nanjing, China, are characterized on the basis of measurements in 2012 and 2013 using the 7-channel Aethalometer (model AE-31, Magee Scientific, USA. The AAC is estimated with direct and indirect corrections, which show 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 urban Nanjing, which is much lower than that in Pearl River Delta and as the same as that in rural areas (Lin'an in Yangtze River Delta. The AAC in urban Nanjing shows strong seasonality (diurnal variations, high in cold seasons (at rush hours and low in summer (in afternoon. It also show synoptic and quasi-two-week cycles in response to weather systems. Its frequency distribution follows a typical lognormal 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 pollutions. Air masses 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 compared to that from the Weingartner correction (Weingartner et al., 2003. Low AAEs mainly appear in summer in response to the relative humidity (RH. AAC increases with increasing AAE at a fixed aerosol loading. The RH-AAC relationship is more complex. Overall, AAC peaks

  7. Multi-scale evaluation of high-resolution multi-sensor blended global precipitation products over the Yangtze River

    Science.gov (United States)

    Li, Zhe; Yang, Dawen; Hong, Yang

    2013-09-01

    In the present study, four high-resolution multi-sensor blended precipitation products, TRMM Multisatellite Precipitation Analysis (TMPA) research product (3B42 V7) and near real-time product (3B42 RT), Climate Prediction Center MORPHing technique (CMORPH) and Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN), are evaluated over the Yangtze River basin from April 2008 to March 2012 using the gauge data. This regional evaluation is performed at temporal scales ranging from annual to daily, based on a number of diagnostic statistics. Gauge adjustment greatly reduces the bias in 3B42 V7, a post real-time research product. Additionally, it helps the product maintain a stable skill level in winter. When additional indicators such as spatial correlation, Root Mean Square Error (RMSE), and Probability of Detection (POD) are considered, 3B42 V7 is not always superior to other products (especially CMORPH) at the daily scale. Among the near real-time datasets, 3B42 RT overestimates annual rainfall over the basin; CMORPH and PERSIANN underestimate it. In particular, the upper Yangtze always suffers from positive bias (>1 mm day-1) in the 3B42 RT dataset and negative bias (-0.2 to -1 mm day-1) in the CMORPH dataset. When seasonal scales are considered, CMORPH exhibits negative bias, mainly introduced during cold periods. The correlation between CMORPH and gauge data is the highest. On the contrary, the correlation between 3B42 RT and gauge data is more scattered; statistically, this results in lower bias. Finally, investigation of the probability distribution functions (PDFs) suggests that 3B42 V7 and 3B42 RT are consistently better at retrieving the PDFs in high-intensity events. Overall, this study provides useful information about the error characteristics associated with the four mainstream satellite precipitation products and their implications regarding hydrological applications over the Yangtze River basin.

  8. Study on joint flood control operation for leading reservoirs in the upper Changjiang River%长江流域上游控制性水库群联合防洪调度研究

    Institute of Scientific and Technical Information of China (English)

    李安强; 张建云; 仲志余; 丁毅

    2013-01-01

      长江流域水系复杂,防洪对象分布范围广,控制性水库的防洪调度目标具有多元化、分布多区域特征,如何科学运用水库防洪库容,有序兼顾各区域防洪是流域控制性水库群联合防洪调度的关键。选取溪洛渡、向家坝与三峡水库组成的水库群为对象,基于大系统分解协调原理,先通过逐次分解各防洪区域对溪洛渡、向家坝两库预留防洪库容的要求,在结合区域间洪水遭遇关联性分析的基础上,提出两库防洪库容在协调川江与长江中下游两区域防洪中的分配方案;同时对三峡水库的防洪调度方式深入优化,提出适当扩大对城陵矶防洪补偿库容分配方案。研究成果表明,联合调度方案可进一步减少长江中下游分洪量,对于提高整个流域防洪减灾水平,完善长江流域库群防洪调度体系具有重要意义。%The Changjiang River possesses a complex river system and widely distributed flood protection objects. As the multi-nurpose of flood control operation for its leading reservoirs involving a wide range of regions, the key for joint flood control operation of leading reservoirs in the river basin lies on utilizing flood control storage reasonably and orderly giving consideration to overall plans flood control for related re⁃gions. Taking a group of reservoirs, Xiluodu, Xiangjiaba and the Three Gorges as the object, this paper proposes flood control storage allocation plan for coordinative flood control of the Chuanjiang and the Changjiang rivers by using the principle of large-scale system decomposition-coordination, through succes⁃sively decomposing the different demands for the flood control storage of Xiluodu and Xiangjiaba reservoirs by the flood protection objects in every region,and analyzing flood strike patterns for the Chuanjiang River and the midstream of the Changjiang River. Further, a flood control operation mode of the Three Gorges

  9. 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.

  10. Nd and Sr isotopic compositions of sediments from the Yellow and Yangtze Rivers: Implications for partitioning tectonic terranes and crust weathering of the Central and Southeast China

    Institute of Scientific and Technical Information of China (English)

    Xianwei MENG; Yanguang LIU; Xuefa SHI; Dewen DU

    2008-01-01

    New Nd and Sr isotope data are presented in this paper for sediments from the Yellow and Yangtze River drainage basins. The average 143Nd/144Nd isotope compositions of fine-grained sediments from two drain-age basins seem similar. The TNdDMages of sediments from the two drainage basins are relatively uniform but exhibit subtle differences. This reflects the different underlying bedrocks, in association with the unique tectonic terranes that comprise central and southeastern China, including the North China Block, the Yangtze Block, the South China Block, the Tibet Plateau and the Qinling-Dabie Orogenic Belt. In contrast, there is an obvious difference in the 878r/86Sr ratios between fine-grained sediments of the Yellow and Yangtze Rivers, which actually reflects an increase in chemical weathering intensity from northwes-tern to southeastern China.

  11. The Impact of China's WTO Entry on the Industrial Structure of the Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-qiong; WANG Wei-gong; LI Zheng; SHAO Shi-huang

    2002-01-01

    In the areas of China access into WTO Agreements,Chinese government has made lots of promises in reducing tariffs of some industrial products. While industrial products make up a very large share of import and export, so nearly all kinds of them will be influenced, especially those which are protected by means of national tariffs and taxes and non-tariffs barriers on import-sand, to a lesser extent, on exports.Meanwhile we have noticed that most of these industries are the pillar ones of Yangtze Delta. As it is well known that Yangtze Delta has become the most developed area in Yangtze valley or even in China and had an important effect on China economy. Thus entry to the WTO requires reform to be accelerated in this district so as to put the industry of this region in a position to be able to cope with the greater foreign competition that will follow accession to the trade body.

  12. Main energy paths and energy cascade processes of the two types of persistent heavy rainfall events over the Yangtze River-Huaihe River Basin

    Science.gov (United States)

    Zhang, Yuanchun; Sun, Jianhua; Fu, Shenming

    2017-02-01

    Two types of persistent heavy rainfall events (PHREs) over the Yangtze River-Huaihe River Basin were determined in a recent statistical study: type A, whose precipitation is mainly located to the south of the Yangtze River; and type B, whose precipitation is mainly located to the north of the river. The present study investigated these two PHRE types using a newly derived set of energy equations to show the scale interaction and main energy paths contributing to the persistence of the precipitation. The main results were as follows. The available potential energy (APE) and kinetic energy (KE) associated with both PHRE types generally increased upward in the troposphere, with the energy of the type-A PHREs stronger than that of the type-B PHREs (except for in the middle troposphere). There were two main common and universal energy paths of the two PHRE types: (1) the baroclinic energy conversion from APE to KE was the dominant energy source for the evolution of large-scale background circulations; and (2) the downscaled energy cascade processes of KE and APE were vital for sustaining the eddy flow, which directly caused the PHREs. The significant differences between the two PHRE types mainly appeared in the lower troposphere, where the baroclinic energy conversion associated with the eddy flow in type-A PHREs was from KE to APE, which reduced the intensity of the precipitation-related eddy flow; whereas, the conversion in type-B PHREs was from APE to KE, which enhanced the eddy flow.

  13. Case studies on mesoscale structures of heavy rainfall system in the Yangtze River generated by Meiyu front

    Institute of Scientific and Technical Information of China (English)

    LIU; Liping; RUAN; Zheng

    2005-01-01

    A heavy rainfall system was observed over the Yangtze River during Meiyu season by using dual-Doppler radar systems in the field experiment conducted by the project of National Fundamental Research Planning "Research on formation mechanism and the prediction theory of hazardous weather over China". The three-dimensional mesoscale kinematic structure and process of a heavy rain on 22 and 23 July, 2002 are investigated by using the radial velocity and dual-Doppler radar technique. The results show that a southwest-northeast oriented rain band with the length of about 1000 km involves numbers of meso-β or meso-γ-scale convective cells with the size of 20―50 km. The heavy rain band in the middle reaches of the Yangtze River exists in a low-level wind shear. The interaction between southwest low-level jet on the southern side of wind shear and east wind on the northern side formed the updraft. The wind disturbance, wind shear and convergence generate the convective action. The new cell developed in right rear flank of rain band and moved to the southwest wind area, where the vapor is abundant. This kind of echo can last a long time and developed well. The strong convective echoes are often accompanied by the meso-γ-scale vortex and convergence.

  14. 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.

  15. A subfossil chironomid-total phosphorus inference model for lakes in the middle and lower reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    ZHANG Enlou; Alan Bedford; Richard Jones; SHEN Ji; WANG Sumin; TANG Hongqu

    2006-01-01

    The results of an investigation into the relationship between surface sediment subfossil chironomid distribution and water quality are presented. Data from 30 lakes in the middle and lower reaches of the Yangtze River indicate that the nutrient gradient was the major factor affecting the distribution of chironomids across these sites. Canonical correspondence analysis (CCA) revealed that of 12 summer water environmental variables, total Phosphorus was most important, accounting for 20.1% of the variance in the chironomid data. This was significant enough to allow the development of quantitative inference models. A TP inference model was developed using weighted averaging (WA), partial least squares (PLS) and weighted averaging partial least squares (WA-PLS). An optimal two-component WA-PLS model provided a high jack-knifed coefficient of prediction for conductivity r 2jack = 0.76, with a low root mean squared error of prediction (RMSEPjack = 0.13). Using this model it is possible to produce long-term quantitative records of past water quality for lacustrine sites across the middle and lower reaches of the Yangtze River, which has important implications for future lake management and ecological restoration.

  16. 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

  17. Effects of disturbance on regeneration of Abies fabri forests at the upper reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    Gao Jia-rong; Gao Yang

    2007-01-01

    Mudflow is the principal disturbance in Abies fabri forests. In the Gongga Mountain areas of the upper reaches of the Yangtze River, the intensities and periodicity of different scale mudflows vary. Small-scale mudflows are more frequent, occurring every one or two years while large-scale mudflows may occur once in more than one hundred years. Through a field study of A. fabri forests during different stages of growth, we analyzed their structural characteristics and discovered that after different sizes of mudflow, poplar and birch often occupy the dominant canopy at the expense of the slow growing A. fabri, for only a small number of saplings are A. fabri that occurs in the first regeneration stage. However, a large number of seed resources can be found in mature A.fabri forests and as a unique regeneration species, A. fabri will gradually replace all the other species and form a stable community of strong shade-tolerant trees. Because of the intimate relationship between growing conditions and soil and water conservation at the upper reaches of the Yangtze River, we should carry out some artificial measurements to control and promote the slow regeneration process of A. fabri.

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. 基于空间变差函数的长江三角洲经济发展差异演变研究%Evolvement of Economic Development Diversity in the Changjiang River Delta Based on Spatial Variogram

    Institute of Scientific and Technical Information of China (English)

    靳诚; 陆玉麒

    2011-01-01

    The unbalanced distribution of economic activities is an overwhelming phenomenon in regional economy. Therefore,the analysis on the diversity of regional economy and its cause is meaningful to accelerate the development of the underdeveloped regions and to maintain its competitiveness of the developed areas.With the help of the spatial variogram,and taking the Changjiang River Delta as an example,this paper aims to describe the economic evolvement among country-level cities spatially since 1978,based on four time sections: 1978,1988,1998 and 2008.Furthermore,it is going to discuss the influential factors of the evolvement of the regional economy diversity in the Changjiang River Delta.Through analysis,the paper finds out some spatial evolvement rules of the economy in the Changjiang River Delta.Firstly,the GDP per capita increases obviously, from 17.1 km in 1978 to 131.8 km in 2008.In addition,Shanghai enhances its economic radiation on the Changjiang River Delta constantly.Secondly,the economic development of Changjiang River Delta shows different structural characteristics in different periods.As time goes by,the spatial self-organized characteristics of the economic development has become stronger and stronger,and the distribution diversity of the spatial economy also gets clearer.Thirdly,in the perspective of spatial fractal dimension,the difference is the most obvious between the direction of the southeast and the northwest,while it is quite balanced between the direction of the east and the west.Fourthly,from the figure of Kriging 3D,the evolvement of the development diversity of the regional economy in Changjiang River Delta can be seen obviously.In 1978,the regional economy in Shanghai,Suzhou and Wuxi cities develops better,while the regions in the south develop slowly;in 1988,the economy of Zhejiang Province develops faster,and some high economic points emerges;in 1998,the high economic point regions expand obviously,which mainly distribute around

  3. Characteristics of the Yangtze River Ecosystem%长江生态系统特征分析

    Institute of Scientific and Technical Information of China (English)

    陈进

    2015-01-01

    According to the basic theory and concept of ecosystem,the features of river ecosystem inclusive of spa-tial and temporal scales and habitats,hydrological processes and material fluxes,aquatic life and human activity impacts are discussed in this paper.Moreover,the environmental features and the mechanism of human activity im-pact in the Yangtze River ecosystem are also analysed through comparing the results of Yangtze scientific investiga-tion with existing research findings.Research results suggest that since the Yangtze River stretches a huge area with different degrees of human activity impact,there are natural,semi-natural and human-influenced river segments. The overall quantity and quality of water meet the needs of economic and social development.However,rare and endemic species are in danger due to rapid changes of habitats and hydrological processes.More attentions should be paid to the protection and management of the ecosystem in the basin.%根据生态系统基本概念及理论,讨论河流生态系统的时空尺度与栖息地、水文过程与物质通量、水生生物及人类活动影响等特征;通过长江科学考察成果跟已有研究成果的对比,分析长江生态系统中的环境特征及人类活动影响机制。研究结果表明:长江水系由于跨越区域大,人类活动影响程度不同,存在自然、半自然及受人类影响强烈的河段;总体水量和水质可以满足人类经济社会发展需要;由于栖息地和水文过程变化剧烈,珍稀和特有物种生存环境堪忧,需要特别重视流域整体生态系统的保护和管理。

  4. [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.

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

    Institute of Scientific and Technical Information of China (English)

    Zhen-chun HAO; Kai TONG; Xiao-li LIU; Lei-lei ZHANG

    2014-01-01

    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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Unusual salinity conditions in the Yangtze estuary in 2006: impacts of an extreme drought or of the Three Gorges Dam?

    Science.gov (United States)

    Dai, Zhijun; Chu, Ao; Stive, Marcel; Zhang, Xiaoling; Yan, Hong

    2011-07-01

    During the extreme dry year of 2006, abnormal salinity conditions in the Changjiang Estuary of the Yangtze River occurred in partial coincidence with the second impoundment phase of the TGD (Three Gorges Dam). Analysis of discharge observations in the upper reaches of the estuary and of salinity observations in the estuary as a whole reveals that in 2006 salinity was over 100 mg/l during 275 days, over 250 mg/l during 75 days and over 400 mg/l during 48 days. It is well known that this is due to extreme low discharges from the upper catchment area into the estuary. Moreover, large amounts of water consumed along the lower reaches of the Yangtze River can also aggravate the low discharges that lead to stronger saltwater intrusion in the estuary. Of the 75 days that salinity was over 250 mg/l, the low discharge was decreased further by 10 to 20% due to water consumption. The additional impact of the impoundment phase of the TGD (lasting 37 days in autumn) was noticeable only during 7 days in 2006. During that period, the relative contributions of the TGD and the water consumption in the lower reaches of the Yangtze River amounted to 70 and 30%, respectively. It may be concluded that the impact of the second impoundment phase of the TGD on salinity intrusion in the estuary was modest, while the extreme drought of 2006 was the dominant cause.

  11. Environmental risk assessments and spatial variations of polycyclic aromatic hydrocarbons in surface sediments in Yangtze River Estuary, China.

    Science.gov (United States)

    Yu, Wenwen; Liu, Ruimin; Xu, Fei; Shen, Zhenyao

    2015-11-15

    In this study, based on sampling data from 30 sites in August 2010, the environmental risks associated with 16 priority PAHs were estimated in surface sediments from the Yangtze River Estuary (YRE). The results indicated that the toxic equivalent quantities of the benzo[a]pyrene (TEQBap) from 30 sites were in the range of 1.93-75.88ngg(-1), and the low-molecular-weight PAHs were the dominated species with higher potential toxicity. The results of the Incremental Lifetime Cancer Risk (ILCR) model indicated that the ILCR values of dermal contact were higher than 10(-6) in the northeast region, suggesting that there were significant potential carcinogenic health risks for fishermen exposure to sedimentary PAHs via dermal contact in these areas. RQ values of PAHs indicated the various distributions of ecological risk levels in the study area. These variations might be caused by the natural and anthropogenic inputs and currents in the YRE.

  12. 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.

  13. Suspended sediment flux modeling with artificial neural network: An example of the Longchuanjiang River in the Upper Yangtze Catchment, China

    Science.gov (United States)

    Zhu, Yun-Mei; Lu, X. X.; Zhou, Yue

    2007-02-01

    Artificial neural network (ANN) was used to model the monthly suspended sediment flux in the Longchuanjiang River, the Upper Yangtze Catchment, China. The suspended sediment flux was related to the average rainfall, temperature, rainfall intensity and water discharge. It is demonstrated that ANN is capable of modeling the monthly suspended sediment flux with fairly good accuracy when proper variables and their lag effect on the suspended sediment flux are used as inputs. Compared with multiple linear regression and power relation models, ANN can generate a better fit under the same data requirement. In addition, ANN can provide more reasonable predictions for extremely high or low values, because of the distributed information processing system and the nonlinear transformation involved. Compared with the ANNs that use the values of the dependent variable at previous time steps as inputs, the ANNs established in this research with only climate variables have an advantage because it can be used to assess hydrological responses to climate change.

  14. Synchrotron X-ray microfluorescence measurement of metal distributions in Phragmites australis root system in the Yangtze River intertidal zone.

    Science.gov (United States)

    Feng, Huan; Zhang, Weiguo; Qian, Yu; Liu, Wenliang; Yu, Lizhong; Yoo, Shinjae; Wang, Jun; Wang, Jia Jun; Eng, Christopher; Liu, Chang Jun; Tappero, Ryan

    2016-07-01

    This study investigates the distributions of Br, Ca, Cl, Cr, Cu, K, Fe, Mn, Pb, Ti, V and Zn in Phragmites australis root system and the function of Fe nanoparticles in scavenging metals in the root epidermis using synchrotron X-ray microfluorescence, synchrotron transmission X-ray microscope measurement and synchrotron X-ray absorption near-edge structure techniques. The purpose of this study is to understand the mobility of metals in wetland plant root systems after their uptake from rhizosphere soils. Phragmites australis samples were collected in the Yangtze River intertidal zone in July 2013. The results indicate that Fe nanoparticles are present in the root epidermis and that other metals correlate significantly with Fe, suggesting that Fe nanoparticles play an important role in metal scavenging in the epidermis.

  15. Changes in stress within grassland ecosystems in the three counties of the source regions of the Yangtze and Yellow Rivers

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Based on a database of more than 40 years of second production process and energy flow records for Maduo,Qumalai and Yushu counties,a dynamic model of the stress within grassland ecosys-tems was established using a nonlinear regression method for this source regions of the Yangtze and Yel-low Rivers.The results show that dynamic curves of stress within grassland ecosystems in the three coun-ties were in the shape of an inverted "U" during the period 1965-2007.It also revealed that the variation in actual amount of livestock inventories reflected the general trends of the stress within the grassland eco-systems in the source regions,although there were many other factors for the increase or reduction in grassland ecosystem stress.

  16. 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.

  17. 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.

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

    Science.gov (United States)

    Huang, Qunfang; Lu, Yuqi

    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 (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. PMID:26225986

  19. Identification of nif genes in N2-fixing bacterial strains isolated from rice fields along the Yangtze River Plain.

    Science.gov (United States)

    Xie, Guang Hui; Cui, Zongjun; Yu, Jun; Yan, Jing; Hai, Weili; Steinberger, Yosef

    2006-01-01

    The aim of this research was to identify nifH and nifHDKYE ' genes in twenty strains of N2-fixing heterotrophic bacteria isolated from rice fields in the Yangtze River Plain. Southern hybridization of the total DNA from each strain was performed with the Klebsiella pneumoniae nifHDKYE ' gene probe (6.2 kb Eco RI fragment from pSA30) and the Azospirillum brasilense nifH gene probe (0.6 kb Eco RI-Hin dIII fragment from pHU8). We found that Eco RI fragments of total DNA from Aeromonas hydrophila HY2, Bacillus azotoformans FD, Bacillus licheniformis NCH1, NCH5, WH4, Bacillus brevis NC2, Bacillus pumilus NC12, Bacillus cereus NCH2, Citrobacter freundii HY5, HY9, Derxia gummosa HZ5, Pseudomonas mendocina HZ1 and Pseudomonas pseudoalcaligenes WH3 were positively hybridized with both of the probes. Agrobacterium radiobacter HY17, Corynebacterium sp. HY12, YZ and Pseudomonas sp. HY11 had Eco RI fragments hybridized with the K. pneumoniae nifHDKYE ' gene probe. An Eco RI fragment of total DNA from Bacillus megaterium YY4 was positively hybridized to the A. brasilense nifH gene probe. No hybridization sign was found in the total DNA fragments from Alcaligenes cupidus YY6 and Corynebacterium sp. NC11 hybridized with either of the gene probes. The data provide the number and size of EcoRI fragments of the total DNA hybridized with the nif gene probes for these strains of rarely studied species, suggesting additional evidence for N2 fixing and nif gene diversity of N2-fixing bacteria in rice fields along the Yangtze River Plain.

  20. 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.

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

    Science.gov (United States)

    Huang, Qunfang; Lu, Yuqi

    2015-07-27

    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.

  2. Genetic diversity in population of largemouth bronze gudgeon (Coreius guichenoti Sauvage et Dabry) from Yangtze River determined by microsatellite DNA analysis.

    Science.gov (United States)

    Zhang, Futie; Tan, Deqing

    2010-01-01

    Largemouth bronze gudgeon (Coreius guichenoti Sauvage et Dabry 1874), one of the endemic fish species in the upper reaches of the Yangtze River in China, is a benthic and potamodromous fish that is typically found in rivers with torrential flow. Three dams in the Yangtze River, Ertan Dam, Three Gorges Dam and Gezhouba Dam, may have had vital impacts on the habitat and spawning behaviors of largemouth bronze gudgeon, and could ultimately threaten the survival of this fish. We studied the population genetic diversity of C. guichenoti samples collected at seven sites (JH, GLP, BX, HJ, MD, SDP and XB) within the Yangtze River and one of its tributaries, the Yalong River. Genetic diversity patterns were determined by analyzing genetic data from 11 polymorphic microsatellite loci. A high genetic diversity among these largemouth bronze gudgeon populations was indicated by the number of microsatellite alleles (A) and the expected heterozygosity (HE). No significant population variation occurred among GLP, BX, HJ and MD populations, but dramatic population differentiation was observed among JH and XB, two dam-blocked populations, versus other populations. Tests for bottlenecks did not indicate recent dramatic population declines and concurrent losses of genetic diversity in any largemouth bronze gudgeon populations. To the contrary, we found that dams accelerated the population differentiation of this fish.

  3. 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.

  4. 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.

  5. The Use of Oral Histories to Identify Criteria for Future Scenarios of Sustainable Farming in the South Yangtze River, China

    Directory of Open Access Journals (Sweden)

    Pingyang Liu

    2016-08-01

    Full Text Available Agricultural practices in Jiangnan water towns have historically been identified as maintaining a balance between human activity and the local environment, but are now a significant local source of water pollution. Using a multi-methods approach, this study deduces the environmental impact of traditional practices, and the socially desired conditions for successfully reintroducing critical ones. Oral histories from 31 farmers in Tianshanzhuang village, South Yangtze River were in order to chart changes in farming practices over four historic periods, and used to estimate the nitrogen and phosphorus burdens per acre. Findings show that the use of Lan River Mud—dredged mud for fertilizer—was key in producing a positive impact, but abandoned after the 1980s. Four criteria hindering reintroduction of traditional practices were identified, and potentially useful but fragmented emerging local candidate practices are considered against these, as are recent practices in Japan. We propose that the cooperation of several stakeholders with various related government departments in China could lead to a portfolio of effective policy changes and should be studied further: to include new methods and uses of Lan River Mud; the integration of aquaculture, leisure and tourism industries with agriculture; and the production of organic produce with well-planned internet-linked sales, delivery and coordination mechanisms.

  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. 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.

  8. 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.

  9. A New Precipitation Index for the Spatiotemporal Distribution of Drought and Flooding in the Reaches of the Yangtze and Huaihe Rivers and Related Characteristics of Atmospheric Circulation

    Institute of Scientific and Technical Information of China (English)

    ZONG Haifeng; ZHANG Qingyun

    2011-01-01

    Characteristics of the spatiotemporal distributions of precipitation anomalies in the reaches of the Yangtze River and Huaihe River (YHR) were studied using EOF method. Four main precipitation patterns for the YHR in summer identified by the first two modes: a region-wide flood over the entire YHR (RWF); a region-wide drought over the entire YHR (RWD); a flood in the south with a drought in the northern region of the Yangtze River (FS-DN); and a drought in the south with a flood in the northern region of the Yangtze River (DS-FN). Based on the first two modes and the actual precipitation departure percentage, a new precipitation index is defined in this paper. The typical flood/drought years associated with the various rainfall patterns defined by this precipitation index are more representative and closer to reality compared to some existing precipitation indexes which just use the area-mean precipitation or the EOF time components individually.The characteristics of atmospheric circulation in summer corresponding to the four main precipitation patterns over the YHR in summer show the features of atmospheric circulation differ in different precipitation pattern years. Although the different patterns share a common main influential circulation system, such as the blocking high over northeastern Asia, the low trough of westerly flows in the mid latitudes, the West Pacific Subtropical High (WPSH), and the high ridge over the Tibet Plateau, the difference in location and intensity of these systems can lead to different distributions of precipitation anomalies.

  10. 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 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 human activities. The position shifts of the estuary caused by the paleo-coastline migration and sea level oscillations since the Holocene is the main cause controlling the Yangtze

  11. 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

  12. 近52年太阳活动与江淮梅雨异常关系分析%Analysis of relationship between solar activities and abnormality of plum rains in Changjiang-Huaihe River Valley in recent 52 years

    Institute of Scientific and Technical Information of China (English)

    程国生; 杜亚军; 陈烨

    2012-01-01

    Floods in China mainly occur in the region of Changjiang-Huaihe River Valley. Floods and droughts in June and July are mostly caused by abnormality of plum rains. To study the influence factors of plum rains, the impact of solar activities on plum rains in the region was analyzed based on the data of sunspots and precipitation in the Changjing-Huaihe fiver region during the plum rains period from 1954 to 2005. The results show that, the maximum trend-coefficient of the precipitation of plum rains is located in Hangzhou area, where solar activities has little impact on plum rains. Impact of solar activities on the precipitation and the intensity of plum rains shows obvious regional characteristics in the Changjiang-Huaihe River region. From north to south of the Changjiang-Huaihe River region, the correlations between solar activity and the precipitation of plum rains are negative, positive, and negative, respectively. In anomalous strong solar activity years, precipitation is less in the north and south and more in the middle of the region; while from north to south, the correlations between the solar activity and the intensity of plum rains are positive and negative, i. e. , generally speaking, in anomalous strong solar activity years, the intensity of plum rains is stronger than normal in the north and weaker than normal in the south of the region. Composite analysis results show that, in low solar activity years, the Changjiang-Huaihe River region is prone to have floods.%我国涝灾主要集中在江淮地区,其中6-7月的旱涝,大部分是由梅雨异常引起的。为了研究梅雨的影响因子,利用1954-2005年太阳黑子、江淮地区33站梅雨期降水资料,分析了太阳活动对江淮地区梅雨的影响。研究表明,梅雨量趋势系数的最大值中心位于杭州地区,而太阳活动与杭州地区的梅雨基本上没有关系。太阳活动对江淮地区梅雨量、梅雨强度的影响具有地域性。

  13. 长江主要城市江段重金属污染状况及特征%Heavy Metal Pollution Along the Yangtze River Stretches of Urban Area in Major Cities

    Institute of Scientific and Technical Information of China (English)

    朱圣清; 臧小平

    2002-01-01

    Since the 1970s, Water Environment Monitoring Center of Yangtze valley has been carrying out the monitoring and research work on deposit material in the main stream of Yangtze and finished significant monitoring and research work on the deposit materials in river sections of urban districts for 21 main cities, such as Panzhihua, Chongqing, Wuhan, Shanghai etc. Based on the monitoring and research results, this paper describes the basic characteristics of deposit materials, the content, distribution and existing state, transfer and transformation characteristics of heavy metal pollutants. The results demonstrate that the heavy metal content in suspended load is higher than that in deposited material for main stream of the Yangtze, the alongshore water zone has been polluted in different degree. Among the 21 main cities on the Yangtze river, the river water pollution along the six cities,i.e. Panzhihua, Yichang, Nanjing, Wuhan, Shanghai, Chongqing, is more serious.

  14. 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.

  15. 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.

  16. Population genetic structure of Siniperca chuatsi in the middle reach of the Yangtze River inferred from mitochondrial DNA and microsatellite loci.

    Science.gov (United States)

    Tian, Changxu; Yang, Min; Liang, Xu-Fang; Cao, Liang; Zheng, Hezi; Zhao, Cheng; Zhu, Kecheng; Yuan, Yongchao

    2015-02-01

    The Chinese mandarin fish (Siniperca chuatsi) is currently one of the most important economic freshwater fish in China, whereas the wild resource has declined dramatically in recent years. In this study, we examined the genetic structure and diversity of five populations from the middle reach of the Yangtze River using mitochondrial cytochrome b sequences and microsatellite markers. This research revealed high genetic diversity and low genetic differentiation of S. chuatsi from these regions. The pairwise Fst values of the two markers showed low and no-significant differentiation among populations. AMOVA analysis of two markers and the haplotype genealogy of the Cytb gene confirmed these results. The STRUCTURE analysis of the microsatellite marker implied that the dam upon the tributary of the Yangtze River blocked the gene flow among those regions. This research will be useful in breeding programs and conservation management of this species.

  17. Influence of interannual variability of Antarctic oscillation on mei-yu along the Yangtze and Huaihe River valley and its importance to prediction

    Institute of Scientific and Technical Information of China (English)

    GAO Hui; XUE Feng1; WANG Huijun1

    2003-01-01

    Both correlation analysis and case study indicate that Antarctic oscillation (AAO) is closely related with summer rainfall in eastern China. When AAO is stronger in boreal spring, especially in May, there is more mei-yu rainfall in summer with a longer period along the Yangtze and Huaihe River valley. In contrast, there is less rainfall with a shorter period corresponding to a weaker AAO. Besides, an anomalous AAO changes the position and intensity of several circulation systems, which are important to summer rainfall along the Yangtze and Huaihe River valley. Furthermore, the Antarctic sea ice is negatively correlated with the intensity of AAO with a 6-month leading time. The result in this study provides a new method for the prediction of mei-yu.

  18. 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.

  19. 重庆寸滩长江大桥主桥设计%Design of Main Bridge of Cuntan Changjiang River Bridge in Chongqing

    Institute of Scientific and Technical Information of China (English)

    唐贺强; 曹洪武; 万田保

    2013-01-01

    The main bridge of Cuntan Changjiang River Bridge in Chongqing is a single-span simply-supported steel box girder suspension bridge with span arrangement 250 m+880 m+250 m.The bridge has two main cables that are the structures of prefabricated parallel high-strength steel wire strands.There are totally 57 pairs of the suspenders arranged for the whole bridge,the suspenders are the structures of prefabricated parallel steel wire strands and are connected with the cable bands by way of pin connection.The tower saddles are the fully cast structures and under a tower saddle,the base plate is arranged and is used as the sliding set.The splay saddles are the base structures and under a splay saddle,the cylindrical steel bearing is arranged.The anchoring systems for the main cables are the shaped steel anchoring systems.The stiffening girder of the bridge is designed as the streamlined flat closed steel box girder that is 3.5 m deep and 42 m wide.The anchorage on both the south and north banks are the gravity anchorage,the foundation for each anchorage is the cast-in-situ enlarged foundation and the body of the anchorage is in U shape in plan.The towers are the reinforced concrete portal frame structures.The two columns of a tower are arranged vertically and the foundation of the tower is the pile foundation with separated pile caps.%重庆寸滩长江大桥主桥为250m+880m+250m的单跨简支钢箱梁悬索桥.该桥设2根主缆,主缆采用预制平行高强钢丝索股结构.全桥共布置57对吊索,吊索采用预制平行钢丝束,与索夹采用销接式连接方式.主索鞍为全铸式结构,鞍底设置座板作为滑动副.散索鞍为底座式结构,底部设置柱面钢支座.主缆锚固系统采用型钢锚固系统.加劲梁采用流线型扁平式封闭钢箱梁,梁高3.5m,宽42 m.南、北锚碇均为重力式锚碇,现浇扩大基础,锚体在平面均呈U形.桥塔为钢筋混凝土门式框架结构,两塔柱竖直布置,基础为分离式承台桩基础.

  20. 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

  1. 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.

  2. Analysis on the Extreme Heat Wave over China around Yangtze River Region in the Summer of 2013 and Its Main Contributing Factors

    Directory of Open Access Journals (Sweden)

    Jin Li

    2015-01-01

    Full Text Available In the summer of 2013, a rare extreme heat wave occurred in the middle and lower reaches of the Yangtze River in China. Based on high resolution reanalysis data from ECMWF, comprehensive analyses on the associated atmospheric circulation and the sea surface temperature anomaly (SSTA were provided. The stable and strong West Pacific Subtropical High (WPSH was the direct cause for the heat wave. The WPSH had four westward extensions, which brought about four hot spells in southern China. The South Asia High (SAH at 150 hPa was more eastward and more northward than normal. The strong Hadley circulation in the central and western Pacific and the anomalous easterlies at 500 hPa and 250 hPa in the middle and high latitudes were favorable for more hot days (HDs. The total HDs in the middle and lower reaches of the Yangtze River had close relationships with the zonal wind anomalies in the middle and high latitudes, the SSTA in the Indian Ocean and Pacific, and the dry soil conditions of the Yangtze River Valley in spring and summer. The anomalies of the tropical, subtropical, and polar circulation and the underlying surfaces could be responsible for this extreme heat wave.

  3. 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.

  4. Changes of Frequency of Summer Precipitation Extremes over the Yangtze River in Association with Large-scale Oceanic-atmospheric Conditions

    Institute of Scientific and Technical Information of China (English)

    WANG Yi; YAN Zhongwei

    2011-01-01

    Changes of the frequency of precipitation extremes (the number of days with daily precipitation exceeding the 90th percentile of a daily climatology,referred to as R90N) in summer (June-August) over the mid-lower reaches of the Yangtze River arc analyzed based on daily observations during 1961-2007.The first singular value decomposition (SVD) mode of R90N is linked to an ENSO-like mode of the sea surface temperature anomalies (SSTA) in the previous winter.Responses of different grades of precipitation events to the climatic mode are compared.It is notable that the frequency of summer precipitation extremes is significantly related with the SSTA in the Pacific,while those of light and moderate precipitation are not.It is suggested that the previously well-recognized impact of ENSO on summer rainfall along the Yangtze River is essentially due to a response in summer precipitation extremes in the region,in association with the East Asia-Pacific (EAP) teleconnection pattern.A negative relationship is found between the East Asian Summer Monsoon (EASM) and precipitation extremes over the mid-lower reaches of the Yangtze River.In contrast,light rainfall processes are independent from the SST and EASM variations.

  5. Study of relationship between water resources protection of Yangtze River and basin economic-social development%长江水资源保护与流域经济社会发展关系研究

    Institute of Scientific and Technical Information of China (English)

    王孟

    2015-01-01

    Yangtze River, the longest river in China, plays a crucial role in the economic-social development of Yangtze Riv-er Basin. Protecting the water resources of Yangtze River concerns the welfare of 400 million people living in the basin, and the sustainable development of Yangtze River Basin or even the whole country. Based on analysis of the relationship between the wa-ter environment change and economic-social development of Yangtze River Basin in the past 30 years, the problems and chal-lenges in water resources protection of Yangtze River are discussed, and suggestions to improve the protection of water resources of Yangtze River are put forward.%长江是中国第一大河,是长江流域经济社会发展的重要命脉,保护好长江水资源,不仅是长江流域4亿多人民的福祉所系,也关系到长江流域乃至全国经济社会可持续发展的大局。在分析近30 a来长江流域经济社会发展与水环境变化关系的基础上,讨论了长江流域水资源保护面临的问题,并提出了加强长江流域水资源保护的思路和对策。

  6. 马鞍山长江公路大桥悬索桥先导索过江施工技术%River-Crossing Construction for Pilot Ropes of Suspension Bridge of Maanshan Changjiang River Highway Bridge

    Institute of Scientific and Technical Information of China (English)

    李猛; 朱小金

    2015-01-01

    马鞍山长江公路大桥左汊主桥为主跨2×1080 m的三塔两跨悬索桥,主缆牵引系统采用先导索过江架设,先导索设计总长2600 m ,分2段,每段1300 m。针对桥址江面宽、悬索桥需两跨过江、跨越长江“黄金航道”、安全要求高、工期紧等因素,对先导索过江方案进行比选,确定该桥先导索采用飞艇过江牵引方案架设。采用T C08X‐2.4G型遥控氦气飞艇牵引先导索,选用φ2 mm迪尼玛绳作为一级导索,采用被动放索装置的力矩电机被动放出先导索。首先由北岸向中塔飞行过江,形成北跨初级牵引系统;然后由中塔向南岸飞行,形成南跨初级牵引系统;最后由人工和卷扬机配合完成1~5级先导索替换,完成先导索过江。飞艇牵引过程中,进行飞行控制、先导索垂度控制和安全控制,保证先导索飞艇过江顺利实施。实践表明,在长江江面不封航情况下,采用飞艇过江牵引方案可以实现先导索安全可靠过江。%The left main bridge of the Maanshan Changjiang River Highway Bridge is a three‐tower suspension bridge with two main spans each of 1 080 m. The traction system for the main cables was erected by using pilot ropes which needed threading across the river .The pilot rope had a total design length of 2 600 m ,which was divided into two sections ,each measuring 1 300 m . Given the fact that the river is wide at the bridge site ,the suspension bridge needs two main spans to cross the river ,more critically ,the suspension bridge crosses the golden navigation channel of Changjiang River ,its safety requirements are demanding and construction schedule is tight ,it is determined via scheme comparison and selection that the pilot ropes be erected by using airship to guide the ropes to cross the river .The TC08X‐2 .4G remote‐controlled helium airship was adopted to guide the pilot ropes .Theφ2 mm Dyneema rope was used as the first

  7. Evaluating health of paddy rice field ecosystem with remote sensing and GIS in Lower Yangtze River Plain, China

    Science.gov (United States)

    Li, Jingjing; Qin, Zhihao; Li, Wenjuan; Lin, Lu

    2008-10-01

    A paddy rice ecosystem is a farming system composed of paddy, animals, microbes and other environmental factors in specific time and space, with particular temporal and spatial dynamics. Since paddy rice is a main grain crop to feed above half of population in China, the performance of paddy rice ecosystem is highly concerned to yield level of paddy and food supply safety in China. Therefore, monitoring the performance of paddy rice ecosystem is very important to obtain the required information for evaluation of ecosystem health. In the study we intend to develop an approach to monitor the ecosystem performance spatially and dynamically in a regional scale using MODIS remote sensing data and GIS spatial mapping. On the basis of key factors governing the paddy rice ecosystem, we accordingly develop the following three indicators for the evaluation: Crop growing index (CGI), environmental Index (EI), and pests-diseases index (PDI). Then, we integrated the three indicators into a model with different weight coefficients to calculate Comprehensive ecosystem health index (CEHI) to evaluate the performance and functioning of paddy rice ecosystem in a regional scale. CGI indicates the health status of paddy rice calculated from the normalizing enhanced vegetation Index (EVI) retrieved from MODIS data. EI is estimated from temperature Index (TI) and precipitation Index (PI) indicating heat and water stress on the rice field. PDI reflects the damage brought by pests and diseases, which can be estimated using the information obtained from governmental websites. Applying the approach to Lower Yangtze River Plain, we monitor and evaluate the performance of paddy rice ecosystem in various stages of rice growing period in 2006. The results indicated that the performance of the ecosystem was generally very encouraging. During booting stage and heading and blooming stage, the health level was the highest in Anhui province, which is the main paddy rice producer in the region

  8. 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

  9. Using drift nets to capture early life stages and monitor spawning of the yangtze river chinese sturgeon (Acipenser sinensis)

    Science.gov (United States)

    Wei, Q.W.; Kynard, B.; Yang, D.G.; Chen, X.H.; Du, H.; Shen, L.; Zhang, H.

    2009-01-01

    A sampling system for capturing sturgeon eggs using a D-shaped bottom anchored drift net was used to capture early life stages (ELS) of Chinese sturgeon, Acipenser sinensis, and monitor annual spawning success at Yichang on the Yangtze River, 1996-2004, before and just after the Three Gorges Dam began operation. Captured were 96 875 ELS (early life stages: eggs, yolk-sac larvae = eleuthero embryos, and larvae); most were eggs and only 2477 were yolk-sac larvae. Most ELS were captured in the main river channel and inside the bend at the Yichang spawning reach. Yolk-sac larvae were captured for a maximum of 3 days after hatching began, indicating quick dispersal downstream. The back-calculated day of egg fertilization over the eight years indicated a maximum spawning window of 23 days (20 October-10 November). Spawning in all years was restricted temporally, occurred mostly at night and during one or two spawning periods, each lasting several days. The brief temporal spawning window may reduce egg predation by opportunistic predators by flooding the river bottom with millions of eggs. During 1996-2002, the percentage of fertilized eggs in an annual 20-egg sample was between 63.5 to 94.1%; however, in 2003 the percentage fertilized was only 23.8%. This sudden decline may be related to the altered environmental conditions at Yichang caused by operation of the Three Gorges Dam. Further studies are needed to monitor spawning and changes in egg fertilization in this threatened population. ?? 2009 Blackwell Verlag GmbH.

  10. 长江河口盐水入侵对大通枯季径流量变化的响应时间%The response time of saltwater intrusion in the Changjiang River Estuary to the change of river discharge in dry season

    Institute of Scientific and Technical Information of China (English)

    侯成程; 朱建荣

    2013-01-01

      应用河口海岸三维数值模式,计算区域包括大通至长江河口及其邻近海域,设计高分辨率网格,数值模拟和分析不同潮型下长江河口盐水入侵对大通径流量变化的响应时间。计算结果表明,不同潮型期间大通径流量的增加,河口盐度响应的时间在4.0~6.2 d之间,但小潮期的响应时间明显长于其他潮型期的响应时间。本文给出了长江河口盐水入侵对大通枯季径流量变化的响应时间,可为河口水文、泥沙和环境等研究中取何时径流量提供了依据。%Based on the 3D numerical model with high resolution grid ,the response time of saltwater intrusion in the Changjiang Estuary to the change of river discharge at Datong in different tidal pattern is studied .The calculat-ed domain of the model includes the lower reaches of the Changjiang River from Datong to the Changjiang Estuary and its adjacent sea .The results show that the time response of saltwater intrusion to the increasing river discharge at Datong in different tidal pattern is 4.0 to 6.2 days ,and is obvious longer in neap tide than the one in other tidal pattern .The response time of saltwater intrusion to the river discharge change in dry season was solved in this pa-per ,which can be as a scientific reference when the river discharge should be used in the studies of hydrology ,sed-iment and environment in the Changjiang Estuary .

  11. SCP-Based Yangtze River Delta Region under the Framework of SWOT Analysis of the Development of 4PL%基于SCP框架下长三角地区发展第四方物流的SWOT分析

    Institute of Scientific and Technical Information of China (English)

    金石

    2012-01-01

    从第四方物流的概念入手,对长三角的物流现状进行分析,旨在找到长三角地区发展第四方物流的方向与方法。随着跨国企业在长三角纷纷落户,长三角与国际经济的合作越发紧密,从某种程度上说,长三角区域内的制造业和服务业等代表了国际发展的趋势和要求,而物流行业又同区域制造业和服务业的发展息息相关,因此,长三角物流行业与国际接轨具有紧迫性。从提高区域经济发展效率看,长三角必须要将第四方物流作为重点领域加以考虑。%From the concept of fourth party logistics,analysis the current situation of logistics of the Yangtze River Delta,to find the fourth party logistics development direction and method of the Yangtze River Delta.Along with the multinational company have settled in the Yangtze River Delta,the Yangtze River Delta and international economic cooperates more closely,to some extent,the manufacturing industry and service industry and so on of the Yangtze River Delta region behalf of the international development trend and requirements,and the logistics industry with regional manufacturing industry and service industry development,therefore,with the urgency of the Yangtze River Delta logistics industry and international to conform.From enhancing regional economic development efficiency,Yangtze River Delta must be considered as key areas of the 4PL.

  12. STUDY ON RIVER-SEA INTERACTION AND FORMATION OF PALEO-YANGTZE GRAND DELTA SYSTEM IN THE AREA OF SOUTH YELLOW SEA AND EAST CHINA SEA%河海交互作用与黄东海域古扬子大三角洲体系研究

    Institute of Scientific and Technical Information of China (English)

    王颖; 邹欣庆; 殷勇; 张永战; 刘绍文

    2012-01-01

    海疆权益维护提供重要的科学依据.%China seas are characterized by river-sea interaction and accumulative continental shelf. With the association of arc islands,there is a set of marginal seas developed along China coastal areas. To carry huge amount of sediments, five of seven large rivers origin from Qinghai-Tibet Plateau ultimately flow into China seas. With sufficient sediments supply,a wide accumulative continental shelf was formed during Cenozoic era. This paper studies geomorphologic formation of the continental shelf in South Yellow Sea and East China Sea, where sediment discharge from the Yellow River and the Changjiang River are the major sources in contributing terrigenous deposits. According to the researches conducted in the last 3 decades,it is eventually realized that,there is a grand delta system distributed in the South Yellow Sea and East China Sea. The base of the system was an original delta, located between 34°30'N to 26°N from north to south,and eastward boundaried as -100~-150m water depth,with the Changjiang River mouth and Hangzhou Estuary as it's centre, forward to sea as a 230° arc shaped delta deposited on the sea bottom. The base delta was formed during Mid-Late Pleistocene when ancient Changjiang River started to run into the Yellow Sea and the East China Sea. This bottom delta was originating from the huge river sediments, discharged from ancient Changjiang and Yellow River, and being reshaped by waves and tidal currents. Upon the huge bottom delta, there are four delta unions superimposed on the top,and developed in different geological time: Paleo Changjiang-Yellow River delta and radiative sand ridge field of Late Pleistocene, Holocene-Modern Changjiang River delta and abandoned Yellow River delta of historical time. The Paleo-Yangtze Grand Delta System geographically covers most areas of East China Sea and South Yellow Sea, which forms continental sedimentary geomorphology. A multidimensional survey to this region is

  13. 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.

  14. 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.

  15. The Impact of Indian Ocean Variability on HighTemperature Extremes across the Southern Yangtze River Valley in Late Summer

    Institute of Scientific and Technical Information of China (English)

    HU Kaiming; HUANG Gang; QU Xia; HUANG Ronghui

    2012-01-01

    In this study,the teleconnection between Indian Ocean sea surface temperature anomalies (SSTAs) and the frequency of high temperature extremes (HTEs) across the southern Yangtze River valley (YRV) was investigated.The results indicate that the frequency of HTEs across the southern YRV in August is remotely influenced by the Indian Ocean basin mode (IOBM) SSTAs.Corresponding to June-July-August (JJA) IOBM warming condition,the number of HTEs was above normal,and corresponding to IOBM cooling conditions,the number of HTEs was below normal across the southern YRV in August.The results of this study indicate that the tropical IOBM warming triggered low-level anomalous anticyclonic circulation in the subtropical northwestern Pacific Ocean and southern China by emanating a warm Kelvin wave in August.In the southern YRV,the reduced rainfall and downward vertical motion associated with the anomalous low-level anticyclonic circulation led to the increase of HTE frequency in August.

  16. Consistent responses of the microbial community structure to organic farming along the middle and lower reaches of the Yangtze River

    Science.gov (United States)

    Wang, Wenhui; Wang, Hui; Feng, Youzhi; Wang, Lei; Xiao, Xingji; Xi, Yunguan; Luo, Xue; Sun, Ruibo; Ye, Xianfeng; Huang, Yan; Zhang, Zhengguang; Cui, Zhongli

    2016-01-01

    Soil microorganisms play a crucial role in the biogeochemical cycling of nutrient elements and maintaining soil health. We aimed to investigate the response of bacteria communities to organic farming over different crops (rice, tea and vegetable) along the middle and lower reaches of the Yangtze River of China. Compared with conventional farming, organic farming significantly increased soil nutrients, soil enzyme activities, and bacterial richness and diversity. A Venn diagram and principal component analysis revealed that the soils with 3 different crops under organic farming have more number and percent of shared OTUs (operational taxonomic units), and shared a highly similar microbial community structure. Under organic farming, several predominant guilds and major bacterial lineages (Rhizobiales, Thiotrichaceae, Micromonosporaceae, Desulfurellaceae and Myxococcales) contributing to nutrient (C, N, S and P) cycling were enriched, whereas the relative abundances of acid and alkali resistant microorganisms (Acidobacteriaceae and Sporolactobacillaceae) were increased under conventional farming practices. Our results indicated that, for all three crops, organic farming have a more stable microflora and the uniformity of the bacterial community structure. Organic agriculture significantly increased the abundance of some nutrition-related bacteria, while reducing some of the abundance of acid and alkali resistant bacteria. PMID:27725750

  17. Deriving Scaling Factors Using a Global Hydrological Model to Restore GRACE Total Water Storage Changes for China's Yangtze River Basin

    Science.gov (United States)

    Long, Di; Yang, Yuting; Yoshihide, Wada; Hong, Yang; Liang, Wei; Chen, Yaning; Yong, Bin; Hou, Aizhong; Wei, Jiangfeng; Chen, Lu

    2015-01-01

    This study used a global hydrological model (GHM), PCR-GLOBWB, which simulates surface water storage changes, natural and human induced groundwater storage changes, and the interactions between surface water and subsurface water, to generate scaling factors by mimicking low-pass filtering of GRACE signals. Signal losses in GRACE data were subsequently restored by the scaling factors from PCR-GLOBWB. Results indicate greater spatial heterogeneity in scaling factor from PCR-GLOBWB and CLM4.0 than that from GLDAS-1 Noah due to comprehensive simulation of surface and subsurface water storage changes for PCR-GLOBWB and CLM4.0. Filtered GRACE total water storage (TWS) changes applied with PCR-GLOBWB scaling factors show closer agreement with water budget estimates of TWS changes than those with scaling factors from other land surface models (LSMs) in China's Yangtze River basin. Results of this study develop a further understanding of the behavior of scaling factors from different LSMs or GHMs over hydrologically complex basins, and could be valuable in providing more accurate TWS changes for hydrological applications (e.g., monitoring drought and groundwater storage depletion) over regions where human-induced interactions between surface water and subsurface water are intensive.

  18. Early Holocene groundwater table fluctuations in relation to rice domestication in the middle Yangtze River basin, China

    Science.gov (United States)

    Liu, Tao; Liu, Yan; Sun, Qianli; Zong, Yongqiang; Finlayson, Brian; Chen, Zhongyuan

    2017-01-01

    The early Holocene environmental amelioration stimulated the trajectory of Neolithic farming cultures and specific geographic settings played a role in determining the nature of these cultures. Using microfossil evidence, the present study reveals that the fluctuations of the groundwater table substantially influenced rice domestication in the Dongting Lake area of the middle Yangtze River basin in the early Holocene. Our 14C-dated sediment core taken from the Bashidang (BSD) Neolithic site contains evidence that the site was a floodplain prior to human occupation ca. 8600 years ago. Poaceae, which contained wild rice (Oryza sp.) as indicated by combined pollen and phytolith evidence, and low counts of freshwater algae indicated a moist site condition. The area then gradually evolved into wetlands as the water table rose, in response to the increasing monsoon precipitation during the early Holocene. This favored rice domestication, assisted by firing and clearing, that continued to flourish for several hundred years. Finally, rice domestication declined during the late stage of the Pengtoushan culture, accompanied by evidence of the expansion of wetlands reflecting the effects of a rising groundwater table that had caused the cessation of rice farming at the Bashidang site after ca. 8000-7900 cal yr BP. This study shows that there are local effects at particular sites that may differ from the trend at the regional scale, necessitating a careful interpretation of the available evidence.

  19. 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.

  20. 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.

  1. Uncertainty analysis of total phosphorus spatial-temporal variations in the Yangtze River Estuary using different interpolation methods.

    Science.gov (United States)

    Liu, Ruimin; Chen, Yaxin; Sun, Chengchun; Zhang, Peipei; Wang, Jiawei; Yu, Wenwen; Shen, Zhenyao

    2014-09-15

    Interpolation processes and results are generally accompanied by uncertainty which affects the spatial and temporal properties of pollutants. Based on the 4 period sample data of total phosphorus (TP) collected from the Yangtze River Estuary (YRE) in 2010 and 2011, the uncertainty of spatial-temporal variation was analyzed with interpolation methods of inverse distance weighted (IDW), local polynomial interpolation (LPI), ordinary kriging (OK) and disjunctive kriging (DK). The root mean square errors (RMSE) and the mean relative errors (MRE) were used to analyze the accuracy of different interpolation methods. The results showed that the uncertainty of DK was the lowest and the uncertainty of LPI was the highest among the 4 methods. The subtraction results between different interpolation methods showed that there was some distinct area of value in the disparate interval (not in [-0.05, 0.05] (mg/L)) in the 4 seasonal results, which was mainly distributed in the boundary region and around some sample sites. Both standard deviation (SD) and coefficient of variance (CV) in August 2010 were the highest in the 4 seasons and annual mean. The uncertainty may be caused by choice of interpolation methods, spatial data discrepancy and the lack of sample data.

  2. Consistent responses of the microbial community structure to organic farming along the middle and lower reaches of the Yangtze River.

    Science.gov (United States)

    Wang, Wenhui; Wang, Hui; Feng, Youzhi; Wang, Lei; Xiao, Xingji; Xi, Yunguan; Luo, Xue; Sun, Ruibo; Ye, Xianfeng; Huang, Yan; Zhang, Zhengguang; Cui, Zhongli

    2016-10-11

    Soil microorganisms play a crucial role in the biogeochemical cycling of nutrient elements and maintaining soil health. We aimed to investigate the response of bacteria communities to organic farming over different crops (rice, tea and vegetable) along the middle and lower reaches of the Yangtze River of China. Compared with conventional farming, organic farming significantly increased soil nutrients, soil enzyme activities, and bacterial richness and diversity. A Venn diagram and principal component analysis revealed that the soils with 3 different crops under organic farming have more number and percent of shared OTUs (operational taxonomic units), and shared a highly similar microbial community structure. Under organic farming, several predominant guilds and major bacterial lineages (Rhizobiales, Thiotrichaceae, Micromonosporaceae, Desulfurellaceae and Myxococcales) contributing to nutrient (C, N, S and P) cycling were enriched, whereas the relative abundances of acid and alkali resistant microorganisms (Acidobacteriaceae and Sporolactobacillaceae) were increased under conventional farming practices. Our results indicated that, for all three crops, organic farming have a more stable microflora and the uniformity of the bacterial community structure. Organic agriculture significantly increased the abundance of some nutrition-related bacteria, while reducing some of the abundance of acid and alkali resistant bacteria.

  3. 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.

  4. 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.

  5. City-specific vehicle emission control strategies to achieve stringent emission reduction targets in China's Yangtze River Delta region.

    Science.gov (United States)

    Zhang, Shaojun; Wu, Ye; Zhao, Bin; Wu, Xiaomeng; Shu, Jiawei; Hao, Jiming

    2017-01-01

    The Yangtze River Delta (YRD) region is one of the most prosperous and densely populated regions in China and is facing tremendous pressure to mitigate vehicle emissions and improve air quality. Our assessment has revealed that mitigating vehicle emissions of NOx would be more difficult than reducing the emissions of other major vehicular pollutants (e.g., CO, HC and PM2.5) in the YRD region. Even in Shanghai, where the emission control implemented are more stringent than in Jiangsu and Zhejiang, we observed little to no reduction in NOx emissions from 2000 to 2010. Emission-reduction targets for HC, NOx and PM2.5 are determined using a response surface modeling tool for better air quality. We design city-specific emission control strategies for three vehicle-populated cities in the YRD region: Shanghai and Nanjing and Wuxi in Jiangsu. Our results indicate that even if stringent emission control consisting of the Euro 6/VI standards, the limitation of vehicle population and usage, and the scrappage of older vehicles is applied, Nanjing and Wuxi will not be able to meet the NOx emissions target by 2020. Therefore, additional control measures are proposed for Nanjing and Wuxi to further mitigate NOx emissions from heavy-duty diesel vehicles.

  6. The SIA method for spatial analysis of precipitation in the upper-middle reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    ZHOUSuoquan; XUEGenyuan; GONGPeng; CHENJingming; ZHANGHongping; ZHOUZhijiang; FANXiong; DENGXiaochun; WUZhanping

    2005-01-01

    Using geographic information system (GIS) techniques and the newest seasonal and annual average precipitation data of 679 meteorological stations from 1971 to 2000, the multiple regressions equations of the precipitation and topographical variables are established to extract the effect of topography on the annual and seasonal precipitation in the upper-middle reaches of the Yangtze River.Then, this paper uses a successive interpolation approach (SIA), which combines GIS techniques with the multiple regressions, to improve the accuracy of the spatial interpolation of annual and seasonal rainfall. The results are very satisfactory in the case of seasonal rainfall, with the relative error of 6.86%, the absolute error of 13.07 mm, the average coefficient of variation of 0.070, and the correlation coefficient of 0.9675; in the case of annual precipitation, with the relative error of 7.34%,the absolute error of 72.1 mm, the average coefficient of variation of 0.092, and the correlation coefficient of 0.9605. The analyses of annual mean precipitation show that the SIA calculation of 3-5 steps considerably improves the interpolation accuracy, decreasing the absolute error from 211.0 mm to 62.4 mm, the relative error from 20.74% to 5.97%, the coefficient of variation from 0.2312 to 0.0761,and increasing the correlation coefficient from 0.5467 to 0.9619. The SIA iterative results after 50 steps identically converge to the observed precipitation.

  7. Analysis of genetic diversity and population structure of Bellamya quadrata from lakes of middle and lower Yangtze River.

    Science.gov (United States)

    Gu, Qianhong; Zhang, Man; Zhou, Chuanjiang; Zhu, Guorong; Dong, Jing; Gao, Yunni; Chen, Jie; Chen, Peng

    2015-10-01

    As an endemic species of freshwater gastropods in China, Bellamya quadrata plays an important role in ecosystem service provision and commercial importance. However, the species is overharvested and its natural habitats are under severe threat due to fragmentation and loss. To estimate the genetic diversity and population structure of B. quadrata, 285 individuals from eight lake populations across middle and lower Yangtze River were sampled. Seven microsatellite loci were genotyped. Our results showed that (i) the genetic diversity of B. quadrata was high in most of the studied populations, yet effective population sizes appear to be rather small in some populations; (ii) low levels of genetic differentiation exists among populations but gene flow was generally high; (iii) no clear geographic or genetic structure was observed in the studied region, implying mechanisms (zoochoric dispersal and anthropogenic translocations) that enhance dispersal and gene flow have promoted population connectivity. However, the comparatively high genetic diversity of B. quadrata could be attributed to a lag phase, suggesting that the genetic diversity of this species may be lost in the future and the priorities for conservation of B. quadrata are necessary.

  8. The forecasting research of early warning systems for atmospheric pollutants: A case in Yangtze River Delta region

    Science.gov (United States)

    Song, Yiliao; Qin, Shanshan; Qu, Jiansheng; Liu, Feng

    2015-10-01

    The issue of air quality regarding PM pollution levels in China is a focus of public attention. To address that issue, to date, a series of studies is in progress, including PM monitoring programs, PM source apportionment, and the enactment of new ambient air quality index standards. However, related research concerning computer modeling for PM future trends estimation is rare, despite its significance to forecasting and early warning systems. Thereby, a study regarding deterministic and interval forecasts of PM is performed. In this study, data on hourly and 12 h-averaged air pollutants are applied to forecast PM concentrations within the Yangtze River Delta (YRD) region of China. The characteristics of PM emissions have been primarily examined and analyzed using different distribution functions. To improve the distribution fitting that is crucial for estimating PM levels, an artificial intelligence algorithm is incorporated to select the optimal parameters. Following that step, an ANF model is used to conduct deterministic forecasts of PM. With the identified distributions and deterministic forecasts, different levels of PM intervals are estimated. The results indicate that the lognormal or gamma distributions are highly representative of the recorded PM data with a goodness-of-fit R2 of approximately 0.998. Furthermore, the results of the evaluation metrics (MSE, MAPE and CP, AW) also show high accuracy within the deterministic and interval forecasts of PM, indicating that this method enables the informative and effective quantification of future PM trends.

  9. Study on the extremely cold winter of 1670 over the middle and lower reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    JunHui Yan; MingQi Li; HaoLong Liu; JingYun Zheng; Hui Fu

    2014-01-01

    The snow-cover days over the middle and lower reaches of the Yangtze River (MLRYR) in the winter of 1670 were extracted from Chinese historical documents. By these records, the winter temperature anomalies (compared to the mean of 1961-1990) recorded at seven meteorological stations and the regional mean winter temperature were estimated. The results show that:(1) There was an average of about 30 snow-cover days over the MLRYR region in 1670, ranging from 11-20 days in Shanghai and eastern Zhejiang to 51-60 days in eastern Hunan Province. The snow-cover days averaged about 40 days in Anqing and Nan-cheng, and ranged from 30 to 40 days in Quzhou, Jingdezhen, and Nanchang;and (2) the regional mean winter temperature in 1670 was estimated to be approximately 4.0 °C lower than that of 1961-1990. The maximum negative anomaly of 5.6 °C oc-curred in Nanchang and the minimum anomaly of-2.8 °C was detected in Quzhou. Both of these were lower than that of the coldest winter during the instrumental observation period of 1951-2010. This research could not only provide a method to es-timate historical climate extremes, but also provide a background to understand the recent instrumentally climate extremes.

  10. Seasonal variation effects on the formation of trihalomethane during chlorination of water from Yangtze River and associated cancer risk assessment.

    Science.gov (United States)

    Liu, Shaogang; Zhu, Zhiliang; Fan, Chenfeng; Qiu, Yanling; Zhao, Jianfu

    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 microg/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 x 10(-5) and 8.86 x 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.

  11. Evolutionary dynamics of ecological niche in three Rhinogobio fishes from the upper Yangtze River inferred from morphological traits.

    Science.gov (United States)

    Wang, Meirong; Liu, Fei; Lin, Pengcheng; Yang, Shaorong; Liu, Huanzhang

    2015-02-01

    In the past decades, it has been debated whether ecological niche should be conserved among closely related species (phylogenetic niche conservatism, PNC) or largely divergent (traditional ecological niche theory and ecological speciation) and whether niche specialist and generalist might remain in equilibrium or niche generalist could not appear. In this study, we employed morphological traits to describe ecological niche and test whether different niche dimensions exhibit disparate evolutionary patterns. We conducted our analysis on three Rhinogobio fish species (R. typus,R. cylindricus, and R. ventralis) from the upper Yangtze River, China. Among the 32 measured morphological traits except body length, PCA extracted the first four principal components with their loading scores >1.000. To find the PNC among species, Mantel tests were conducted with the Euclidean distances calculated from the four principal components (representing different niche dimensions) against the pairwise distances calculated from mitochondrial cytochrome b sequence variations. The results showed that the second and the third niche dimension, both related to swimming ability and behavior, exhibited phylogenetic conservatism. Further comparison on niche breadth among these three species revealed that the fourth dimension of R. typus showed the greatest width, indicating that this dimension exhibited niche generalism. In conclusion, our results suggested that different niche dimensions could show different evolutionary dynamic patterns: they may exhibit PNC or not, and some dimensions may evolve generalism.

  12. 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.

  13. Unraveling El Niño's impact on the East Asian Monsoon and Yangtze River summer flooding

    Science.gov (United States)

    Zhang, Wenjun; Jin, Fei-Fei; Stuecker, Malte F.; Wittenberg, Andrew T.; Timmermann, Axel; Ren, Hong-Li; Kug, Jong-Seong; Cai, Wenju; Cane, Mark

    2016-11-01

    Strong El Niño events are followed by massive summer monsoon flooding over the Yangtze River basin (YRB), home to about a third of the population in China. Although the El Niño-Southern Oscillation (ENSO) provides the main source of seasonal climate predictability for many parts of the Earth, the mechanisms of its connection to the East Asian monsoon remain largely elusive. For instance, the traditional Niño3.4 ENSO index only captures precipitation anomalies over East Asia in boreal winter but not during the summer. Here we show that there exists a robust year-round and predictable relationship between ENSO and the Asian monsoon. This connection is revealed by combining equatorial (Niño3.4) and off-equatorial Pacific sea surface temperature anomalies (Niño-A index) into a new metric that captures ENSO's various aspects, such as its interaction with the annual cycle and its different flavors. This extended view of ENSO complexity improves predictability of YRB summer flooding events.

  14. 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.

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

    Science.gov (United States)

    Huang, Kan; Fu, Joshua S; Gao, Yang; Dong, Xinyi; Zhuang, Guoshun; Lin, Yanfen

    2014-01-01

    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.

  16. 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.

  17. 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.

  18. 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

  19. Quantifying uncertainty in the impacts of climate change on river discharge in sub-catchments of the River Yangtze and Yellow Basins, China

    Directory of Open Access Journals (Sweden)

    H. Xu

    2010-09-01

    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 River Yangtze and Yellow 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 great 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

  20. Adjoint Sensitivity Experiments of a Meso-β-scale Vortex in the Middle Reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A relatively independent and small-scale heavy rainfall event occurred to the south of a slow eastward-moving meso-α-scale vortex. The analysis shows that a meso-β-scale system is heavily responsible for the intense precipitation. An attempt to simulate it met with some failures. In view of its small scale, short lifetime and relatively sparse observations at the initial time, an adjoint model was used to examine the sensitivity of the meso-β-scale vortex simulation with respect to initial conditions. The adjoint sensitivity indicates how small perturbations of initial model variables anywhere in the model domain can influence the central vorticity of the vortex. The largest sensitivity for both the wind and temperature perturbation is located below 700 hPa, especially at the low level. The largest sensitivity for the water vapor perturbation is located below 500 hPa, especially at the middle and low levels. The horizontal adjoint sensitivity for all variables is mainly located toward the upper reaches of the Yangtze River with respect to the simulated meso-β-scale system in Hunan and Jiangxi provinces with strong locality. The sensitivity shows that warm cyclonic perturbations in the upper reaches can have a great effect on the development of the meso-β-scale vortex. Based on adjoint sensitivity, forward sensitivity experiments were conducted to identify factors influencing the development of the meso-β-scale vortex and to explore ways of improving the prediction. A realistic prediction was achieved by using adjoint sensitivity to modify the initial conditions and implanting a warm cyclone at the initial time in the upper reaches of the river with respect to the meso-β-scale vortex,as is commonly done in tropical cyclone prediction.

  1. 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

  2. 三峡水库建成后对长江河床演变的影响%Possible Influences of the Three-Gorges Reservoir on Evolution of Changjiang River-Bed

    Institute of Scientific and Technical Information of China (English)

    刁承泰; 刘树人; 穆桂春

    2004-01-01

    After the completion of the three-gorges reservoir, it is inevitable that fluvial processes on the upper river and the lower river of the reservoir will be changed, which causes the evolution of Changjiang river-bed. Firstly, river mouth bars and subaqueous deltas will form because of a high-speed fluvial deposit of tributaries at river mouths where the tributaries flow into the reservoir and its lower reservoir area. Secondly, a series of deformations will occurr in the upper river course near the reservoir and banks along the reservoir after the reservoir retains water, and last tens years. Thirdly, a series of erosions on river-bed and deformations of river course will occurr in the lower river of the reservoir because of unmixed water flows when the reservoir sluices, which will influence seriously on Wuhan city and Jinjiang, a section of Changjiang River from Yichang city to Wuhan city. These processes must be studied and calculated as soon as possible in Hubei province and Chongqing municipality in order that the countermeasures can be made promptly.%长江三峡水库是特大型水库. 长江三峡水利枢纽建成后, 由于水动力条件改变, 引起水库上、下河段河流地貌发育过程的一系列变化, 对环境产生如下冲击和影响: ①基准面抬高, 流入水库各条支流在入库河口区及以下区域迅速产生水下淤积, 形成河口拦门沙和水下三角洲. ②水库上游河道发生变形. 水库蓄水后引起库岸变形, 这种库岸变形可能延续几十年的时间, 影响到库岸的稳定性、水库库区附近淹没浸没以及水库渗漏等. 水库运营时清水下泄, 引起水库下游河床冲刷以及下游河道变形, 受影响最大的是武汉及其以上荆江河段.根据三峡库区的实际情况, 认为影响最大、最应该立项和进行综合研究的问题有3个方面: 第一, 入库河流河口地区的水下淤积问题; 第二, 水库运营过程中引起的库岸变

  3. THREE-DIMENSIONAL MATHEMATICAL MODEL AND ITS APPLICATION IN THE NEIGHBORHOOD OF THE THREE GORGES RESERVOIR DAM IN THE YANGTZE RIVER

    Institute of Scientific and Technical Information of China (English)

    方红卫; Wolfgang Rodi

    2002-01-01

    The calculation of flow and sediment transport is one of the most important tasks in river engineering. The task is particularly difficult because a number of complex physical phenomena should be accounted for more realistically in a model with a predictive power. Three-dimensional calculations of river flow and suspended sediment transport are performed in this paper with application in the Three Gorges Reservoir in the Yangtze River. A period of 76 years after the dam is built is simulated and the results are compared with laboratory measurements obtained by Tsinghua University whereby the model is verified and calibrated. Generally speaking, the calculated results agree well with the experiments, demonstrating that the present model can be used for flow and sediment transport prediction in rivers.

  4. 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.

  5. Study on real-time prediction of oil spill in Changjiang River Estuary and its adjacent sea areas%长江口及邻近海域溢油实时预测研究

    Institute of Scientific and Technical Information of China (English)

    潘冲; 王惠群; 管卫兵; 杨扬

    2011-01-01

    Changjiang River Estuary is located in the most important economic zone in China, where busy shipping, extensive petrochemical industry as well as more and more ocean engineering result in significantly increasing risks of oil spill pollution. In this study, we have established a three-dimensional unstructured triangular grid hydrodynamic model coupling wind current, tidal current and baroclinic current for Changjiang River Estuary and its adjacent sea areas based on the SELFE (Semi-implicit Eulerian-Lagrangian Finite Element) model, which is the newly developed finite element model in the world with high numerical accuracy, computational efficiency and stability. Verifications of the model results against historical and field data prove that the hydrodynamic model can reflected the hydrodynamic features of the study area well. Based on the hydrodynamic model and the theory of Eulerian-Lagrangian method and random walk, a three-dimensional particle diffusion model considering evaporation processes and wave effects has been developed for the spilled oil slick. Combined with the real-time forecast of wind field and corresponding wave data, the whole model system is suitable for predicting unexpected oil spilling in study area. The model was verified with simulated oil spill with the observations of surface drift floats, which showed good numerical behavior of the model. Two numerical experiments were carried out to understand the responses of the spilled oil to the wind and to inspect the applicability of the whole oil spill prediction system for Changjiang River Estuary and its adjacent waters. In the experiments, southeast wind and northwest wind were used to represent the typical winds of summer and winter, respectively. The results show that at the position outside the deep channel, the spilled oil slick drifts spirally toward southeast under the influence of tidal fluctuation, northwest wind and the Changjiang diluted water, while it drifts spirally northward

  6. 长江生态航运文化评价指标体系构建%Yangtze River Ecological Shipping Culture Evaluation Index System Building

    Institute of Scientific and Technical Information of China (English)

    瞿群臻; 李立鑫

    2013-01-01

    长江航运文化建设是长江航运产业发展战略的重要组成部分,当前生态文化成为各行业、各地区的热点,长江流域各地区都加大了对长江生态航运文化建设的重视。文中在深入研究长江航运文化各层面具体内容的基础上,融入生态化因素,提炼出包含11个物质层指标、6个精神层指标、4个制度层指标、3个行为层指标在内的评价指标体系,并运用模糊综合评价法构建了长江生态航运文化建设水平评价模型,以专家问卷调研结果作为依据,对当前的建设水平进行评价。提出了诸如创新航运企业员工培训和绩效管理体系、出台有利于航运文化生态化发展的法规体系、引导生态化主题活动向小型化和多样化发展、用外在激励和内在激励相结合的手段激发员工的生态化行为等建设措施。%The Yangtze river shipping culture construction is an important part of the Yangtze river shipping industry development strategy.Ecological culture has been hot spots of all the industries and regions in recent years,all the areas of the Yangtze river basin have lay more attention to the construction of Yangtze river ecological shipping cultural.Basing on the in-depth study of the specific content of different levels of the Yangtze river shipping culture,considering the ecological factors,the paper designs a set of evaluation index system involving 1 1 physical index,6 spiritual layer index,4 system layer index,3 behavior layer index,then makes the appraisal model of the Yangtze river ecological shipping culture using fuzzy comprehensive evaluation method.Making the result of experts questionnaire survey as the basis,the paper evaluates the current construction level,then proposes several measures,such as reforming staff training and performance management system in shipping enterprises,issuing laws and regulations system that make shipping cultural ecological,miniaturizing and

  7. 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.

  8. 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

  9. The variation of floods in the middle reaches of the Yangtze River and its teleconnection with El Niño events

    Directory of Open Access Journals (Sweden)

    Y.-J. Wu

    2006-01-01

    Full Text Available Middle reaches of the Yangtze River are the worst flooded segments along the Yangtze River. It is important to understand and study the variations of frequency and magnitude of historical floods in this area and how were they related to or affected by EI Niño in a long historical period. We applied the statistics and time series to study and analyze historical floods (1470-2000 and EI Niño events (1525-1995. The results show that the more floods occurred in the latest 200 years. The power-spectral analysis suggests the main cycle of flood variation is longer than that of EI Niño events. El Nino shows the fluctuations of about 2-year and 3~4 year period while the flood variation is not so significant but can also be identified in the period of 2, 8 and 40 years (it exceeds the level of confidence 0.03. Time series analyses of the fluctuation of flood and El Nino indicate that there is a significant correlation between the two at both high and moderate frequency sections. The result shows that the response of the floods along the middle reaches of the Yangtze River to the effects of El Nino events is not only delayed one or more than one year as suggested by many Chinese scientists, but it also can be somewhat longer delayed up to about 8 years. The result also indicates that the shorter the interval of EI Niño events, the sooner the flood events follows. In other words, flood could be delayed with longer time if the interval time of EI Niño events is longer.

  10. Heavy metal pollution of lakes along the mid-lower reaches of the Yangtze River in China: intensity, sources and spatial patterns.

    Science.gov (United States)

    Zeng, Haiao; Wu, Jinglu

    2013-02-26

    Lakes in the middle and lower reaches of the Yangtze River form a shallow lake group unique in the World that is becoming increasingly polluted by heavy metals. Previous studies have largely focused on individual lakes, with limited exploration of the regional pattern of heavy metal pollution of the lake group in this area. This paper explores the sources, intensity and spatial patterns of heavy metal pollution of lake sediments. A total of 45 sample lakes were selected and the concentrations of key metal elements in the sediments of each lake were measured. The cluster analysis (CA), principal component analysis (PCA) and Geo-accumulation index (I(g)) analysis permitted analysis of the source and pollution intensity of the target lakes. Results suggested a notable spatial variation amongst the sample lakes. Lakes in the upper part of the lower reach of the Yangtze River surrounded by typical urban landscapes were strongly or extremely polluted, with high concentrations of Pb, Zn, Cu and Cd in their sediments. This was attributed to large amount of untreated industrial discharges and municipal sewage produced within the lake catchments. In contrast, the heavy-metal pollution of lakes in the Taihu Delta area was notably lower due to industrial restructuring and implementation of effective environmental protection measures. Lakes along the middle reach of Yangtze River surrounded by agricultural areas were unpolluted to moderately polluted by heavy metals overall. Our results suggested that lakes in the central part of China require immediate attention and efforts should be made to implement management plans to prevent further degradation of water quality in these lakes.

  11. Monitoring Perennial Sub-Surface Waterlogged Croplands Based on MODIS in Jianghan Plain, Middle Reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    XIAO Fei; LI Yuan-zheng; DU Yun; LING Feng; YAN Yi; FENG Qi; BAN Xuan

    2014-01-01

    Perennial waterlogged soil (PWS) is induced by the high level of groundwater, and has a persistent impact on natural ecosystems and agricultural production. Traditionally, distribution information regarding PWS is mainly collected from in situ measurements through groundwater level surveys and physicochemical property analyses. However, in situ measurements of PWS are costly and time-consuming, only rough estimates of PWS areas are available in some regions. In this paper, we developed a method to monitor the perennial waterlogged cropland using time-series moderate resolution imaging spectroradiometer (MODIS) data. The Jianghan Plain, a lfoodplain located in the middle reaches of the Yangtze River, was selected as the study area. Temporal variations of the enhanced vegetation index (EVI), night land surface temperature (LST), diurnal LST differences (∆LST), albedo, and the apparent thermal inertia (ATI) were used to analyze the ecological and thermodynamic characteristics of the waterlogged croplands. To obtain pure remote sensing signatures of the waterlogged cropland from mixed pixels, the croplands were classiifed into different types according to soil and land cover types in this paper, and a linear mixing model was developed by iftting the signatures using the multiple linear regression approach. Afterwards, another linear spectral mixing model was used to get the proportions of waterlogged croplands in each 1 km×1 km pixel. The result showed an acceptable accuracy with a root-mean-square error of 0.093. As a tentative method, the procedure described in this paper works efifciently as a method to monitor the spatial patterns of perennial sub-surface waterlogged croplands at a wide scale.

  12. Prevalence of sulfonamide and tetracycline resistance genes in drinking water treatment plants in the Yangtze River Delta, China.

    Science.gov (United States)

    Guo, Xueping; Li, Jing; Yang, Fan; Yang, Jie; Yin, Daqiang

    2014-09-15

    The occurrence and distribution of antibiotic resistance genes (ARGs) in drinking water treatment plants (DWTPs) and finished water are not well understood, and even less is known about the contribution of each treatment process to resistance gene reduction. The prevalence of ten commonly detected sulfonamide and tetracycline resistance genes, namely, sul I, sul II, tet(C), tet(G), tet(X), tet(A), tet(B), tet(O), tet(M) and tet(W) as well as 16S-rRNA genes, were surveyed in seven DWTPs in the Yangtze River Delta, China, with SYBR Green I-based real-time quantitative polymerase chain reaction. All of the investigated ARGs were detected in the source waters of the seven DWTPs, and sul I, sul II, tet(C) and tet(G) were the four most abundant ARGs. Total concentrations of ARGs belonging to either the sulfonamide or tetracycline resistance gene class were above 10(5) copies/mL. The effects of a treatment process on ARG removal varied depending on the overall treatment scheme of the DWTP. With combinations of the treatment procedures, however, the copy numbers of resistance genes were reduced effectively, but the proportions of ARGs to bacteria numbers increased in several cases. Among the treatment processes, the biological treatment tanks might serve as reservoirs of ARGs. ARGs were found in finished water of two plants, imposing a potential risk to human health. The results presented in this study not only provide information for the management of antibiotics and ARGs but also facilitate improvement of drinking water quality.

  13. Interannual variability of the Meiyu onset over Yangtze-Huaihe River Valley and analyses of its previous strong influence signal

    Institute of Scientific and Technical Information of China (English)

    WANG Jing; HE JinHai; LIU XuanFei; WU BinGui

    2009-01-01

    Meiyu onset (MO) over Yangtze-Huaihe River Valley (YHRV) possesses obvious characteristics of in-terannual variations. Based on NCEP/NCAR reanalysis data sets, NOAA OLR and ERSST data, the in-terannual variability of MO(IVMO) and its previous strong influence signal (PSIS) are investigated. The possible mechanisms that the PSIS affecting IVMO are also discussed. The results show that the pre-vious CP-ENSO (Central Pacific El Nino/Southern Oscillation) event is the PSIS affecting IVMO and it has a better accuracy rate of short-term climate prediction and practicality. The MO is most likely to be late (early) with the warm (cold) phase of CP-ENSO in previous boreal February and spring. CP-ENSO affects MO mainly by means of EAP (East Asian-Pacific) or JP (Japanese-Pacific) teleconnection, in which the tropical western North Pacific anticyclone plays an important role. In the years of CP-ENSO warm phase, the tropical warm wet water vapor transportation to YHRV is late. The anomalous positive sea surface temperature near the equatorial central Pacific results in late northward jump of the west-ern Pacific subtropical high and late establishment of Indian southwest monsoon via air-sea interaction, which leads to late seasonal transition of the atmospheric circulations over East Asia from boreal spring to summer. Late seasonal transition of the atmospheric circulations and late tropical warm wet water vapor transport to YHRV are the primary reasons that cause the late MO. The situations are directly opposite in the years of CP-ENSO cold phase.

  14. Using Moving North Pacific Index to Improve Rainy Season Rainfall Forecast over the Yangtze River Basin by Analog Error Correction

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    A new analog error correction (AEC) scheme based on the moving North Pacifi c index (MNPI) is designed in this study. This scheme shows obvious improvement in the prediction skill of the operational coupled general circulation model (CGCM) of the National Climate Center of China for the rainy season rainfall (RSR) anomaly pattern correlation coeffi cient (ACC) over the mid-to-lower reaches of the Yangtze River (MLRYR). A comparative analysis indicates that the eff ectiveness of the new scheme using the MNPI is better than the system error correction scheme using the North Pacifi c index (NPI). A Euclidean distance-weighted mean rather than a traditional arithmetic mean, is applied to the integration of the analog year’s prediction error fi elds. By using the MNPI AEC scheme, independent sample hindcasts of RSR during the period 2003–2009 are then evaluated. The results show that the new scheme exhibited a higher forecast skill during 2003–2009, with an average ACC of 0.47;while the ACC for the NPI case was only 0.19. Furthermore, the forecast skill of the RSR over the MLRYR is examined. In the MNPI case, empirical orthogonal function (EOF) was used in the degree compression of the prediction error fi elds from the CGCM, whereas the AEC scheme was applied only to its fi rst several EOF components for which the accumulative explained variance accounted for 80%of the total variance. This further improved the ACC of the independent sample hindcasts to 0.55 during the 7-yr period.

  15. Accumulation, transfer, and environmental risk of soil mercury in a rapidly industrializing region of the Yangtze River Delta, China

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Biao; Yan, Lianxiang; Sun, Weixia; Zhao, Yongcun; Shi, Xuezheng [Chinese Academy of Sciences, Nanjing (China). State Key Lab. of Soil and Sustainable Agriculture; Wang, Mei [Chinese Academy of Sciences, Nanjing (China). State Key Lab. of Soil and Sustainable Agriculture; Graduate Univ. of the Chinese Academy of Sciences, Beijing (China); Weindorf, David C. [Louisiana State Univ., Baton Rouge, LA (United States). AgCenter

    2011-06-15

    Purpose: Mercury (Hg) accumulation and transfer in soil ecosystems has been altered on local, regional, and even global scales, and their environmental risk has increasingly been a concern to the public and the scientific community. Materials and methods: A county level region in Zhangjiagang County, the Yangtze River Delta (YRD) region of China and a factory with Hg-contaminated wastewater discharging within the region were selected to study the accumulation, bioavailability, and transfer of Hg from different sources in soils and crops under rapid industrialization, urbanization, and intensive agricultural activities. Regional soil samples close to and away from factories and local soil and crop samples around a typical factory were collected in the YRD region of China. Soil and crop Hg and basic soil properties were examined. Results and discussion: Significant soil Hg accumulation was found in soils away from factories regardless of Cambosols (Entisols) and Anthrosols (Inceptisols), while the mobile HCl-extractable Hg (HCl-Hg) were greater in soils closer to factories due to a decrease and increase in soil pH and organic matter. A high level of soil total Hg (T-Hg) was found around the factory, and soil and crop Hg accumulation in the vicinity of the factory was localized with an exponential decrease as distance away from the wastewater discharge outlet increased. Although Hg accumulated in these soils, the T-Hg levels at only a few sampling sites in acidic Anthrosols area were found to exceed the second most stringent critical value of Chinese Environmental Quality Standards for Soils. Conclusions: Considering the cessation of Hg-containing agrochemicals and limitation of effects of industrial activities on Hg accumulation, more attention should be paid to the changes in soil properties and crop rotations than controlling the pathways of Hg entering soils because the current environmental risk is mobilization of accumulated soil Hg. (orig.)

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

    Science.gov (United States)

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

    2007-07-01

    We examined the variation in aboveground biomass accumulation and tissue concentrations of nitrogen (N), phosphorus (P), copper (Cu), zinc (Zn) and lead (Pb) in Phragmites australis (common reed), Spartina alterniflora (salt cordgrass), and Scirpus mariqueter throughout the growing season (April-October 2005), in order to determine the differences in net element accumulation and distribution between the three salt marsh macrophytes in the Yangtze River estuary, China. The aboveground biomass was significantly greater in the plots of S. alterniflora than in the plots of P. australis and S. mariqueter throughout the growing season (Pbiomass was 1246+/-89 gDW/m(2), 2759+/-250 gDW/m(2) and 548+/-54 gDW/m(2) for P. australis, S. alterniflora and S. mariqueter, respectively. The concentrations of nutrients and heavy metals in plant tissues showed similar seasonal patterns. There was a steady decline in element concentrations of the aboveground tissues from April to October. Relative element concentrations in aboveground tissues were at a peak during the spring sampling intervals with minimum levels during the fall. But the concentrations of total nitrogen and total phosphorus in the belowground tissues were relatively constant throughout growing season. Generally, trace metal concentrations in the aboveground tissues of S. mariqueter was the highest throughout the growing season, and the metal concentrations of S. alterniflora tissues (aboveground and belowground) were greater than those of P. australis. Furthermore, the aboveground pools of nutrients and metals were consistently greater for S. alterniflora than for P. australis and S. mariqueter, which suggested that the rapid replacement of native P. australis and S. mariqueter with invasive S. alterniflora would significantly improve the magnitude of nutrient cycling and bioavailability of trace metals in the salt marsh and maybe transport more toxic metals into the water column and the detrital food web in the

  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. Methane emissions from rice fields under continuous straw return in the middle-lower reaches of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    Pengfu Hou; Ganghua Li; Shaohua Wang; Xin Jin; Yiming Yang; Xiaoting Chen; Chengqiang Ding

    2013-01-01

    A three-year experiment was conducted in the middle-lower reaches of the Yangtze River in China to study the influence of continuous wheat straw return during the rice season and continuous rice straw return in wheat on methane (CH4) emissions from rice fields in which,the rice-wheat rotation system is the most dominant planting pattern.The field experiment was initiated in October 2009 and has continued since the wheat-growing season of that year.The analyses for the present study were conducted in the second (2011) and third (2012) rice growing seasons.Four treatments,namely,the continuous return of wheat straw and rice straw in every season (WR),of rice straw but no wheat straw return (R),of wheat straw but no rice straw return (W) and a control with no straw return (CK),were laid out in a randomized split-plot design.The total seasonal CH4 emissions ranged from 107.4 to 491.7 kg/ha (2011) and 160.3 to 909.6 kg/ha (2012).The increase in CH4 emissions for treatments WR and W were 289% and 230% in the second year and 185% and 225% in the third year,respectively,in relation to CK.We observed less methane emissions in the treatment R than in CK by 14%-43%,but not statistically significant.Treatment R could increase rice productivity while no more CH4 emission occurs.The difference in the total CH4 emissions mainly related to a difference in the methane flux rate during the first 30-35 days after transplant in the rice growing season,which was caused by the amount of dissolved oxygen in paddy water and the amount of reducible soil materials.

  19. Projection of summer precipitation over the Yangtze-Huaihe River basin using multimodel statistical downscaling based on canonical correlation analysis

    Science.gov (United States)

    Wu, Dan; Jiang, Zhihong; Ma, Tingting

    2016-12-01

    By using observational daily precipitation data over the Yangtze-Huaihe River basin, ERA-40 data, and the data from eight CMIP5 climate models, statistical downscaling models are constructed based on BP-CCA (combination of empirical orthogonal function and canonical correlation analysis) to project future changes of precipitation. The results show that the absolute values of domain-averaged precipitation relative errors of most models are reduced from 8%-46% to 1%-7% after statistical downscaling. The spatial correlations are all improved from less than 0.40 to more than 0.60. As a result of the statistical downscaling multimodel ensemble (SDMME), the relative error is improved from-15.8% to-1.3%, and the spatial correlation increases significantly from 0.46 to 0.88. These results demonstrate that the simulation skill of SDMME is relatively better than that of the multimodel ensemble (MME) and the downscaling of most individual models. The projections of SDMME reveal that under the RCP (Representative Concentration Pathway) 4.5 scenario, the projected domain-averaged precipitation changes for the early (2016-2035), middle (2046-2065), and late (2081-2100) 21st century are-1.8%, 6.1%, and 9.9%, respectively. For the early period, the increasing trends of precipitation in the western region are relatively weak, while the precipitation in the east shows a decreasing trend. Furthermore, the reliability of the projected changes over the area east of 115 ◦ E is higher than that in the west. The stations with significant increasing trends are primarily located over the western region in both the middle and late periods, with larger magnitude for the latter. Stations with high reliability mainly appear in the region north of 28.5 ◦ N for both periods.

  20. Ecophysiological characteristics of invasive Spartina alterniflora and native species in salt marshes of Yangtze River estuary, China

    Science.gov (United States)

    Jiang, Li-Fen; Luo, Yi-Qi; Chen, Jia-Kuan; Li, Bo

    2009-01-01

    Biological invasions represent one of the significant components of global change. A comparative study of invaders and co-occurring natives is a useful approach to gaining insights into the invasiveness of exotic plants. Spartina alterniflora, a C 4 grass, is a widespread invader in the coastal wetlands in China and other regions of the world. We conducted a comparative study of S. alterniflora and native C 3 species, Phragmites australis and Scirpus mariqueter, in terms of their gas exchange and efficiencies in resource utilization. We tested the hypothesis that S. alterniflora has growth-related ecophysiological advantages over the natives in its non-native range, which result in its rapid growth and enhance its invasiveness. Photosynthesis, leaf area index (LAI), specific leaf area (SLA), and the efficiency of resource use (light, water, and nitrogen) were examined monthly for eight months in 2004. Overall, S. alterniflora had greater LAI, higher maximal net photosynthetic rate ( Amax), and longer growing season than those of the native species. On average, the efficiencies of S. alterniflora in light, water, and nitrogen utilization were respectively 10.1%, 26.1%, and 33.1% higher than those of P. australis, and respectively 70.3%, 53.5%, 28.3% higher than those of S. mariqueter. However, SLA of S. alterniflora was significantly lower than those of P. australis and S. mariqueter. Although there was no general pattern in the relationship between invasiveness and plant photosynthetic types, in this study, most of the ecophysiological characteristics that gave S. alterniflora a competitive advantage in the Yangtze River estuary were associated with photosynthetic pathways. Our results offer a greater understanding of the relationship between invasiveness and plant photosynthetic type. Our results also indicate that LAI and the length of the photosynthetic season, which vary with habitats, are also important in invasion success.

  1. Spatiotemporal changes in precipitation extremes over Yangtze River basin, China, considering the rainfall shift in the late 1970s

    Science.gov (United States)

    Gao, Tao; Xie, Lian

    2016-12-01

    Precipitation extremes are the dominated causes for the formation of severe flood disasters at regional and local scales under the background of global climate change. In the present study, five annual extreme precipitation events, including 1, 7 and 30 day annual maximum rainfall and 95th and 97.5th percentile threshold levels, are analyzed relating to the reference period 1960-2011 from 140 meteorological stations over Yangtze River basin (YRB). A generalized extreme value (GEV) distribution is applied to fit annual and percentile extreme precipitation events at each station with return periods up to 200 years. The entire time period is divided into preclimatic (preceding climatic) period 1960-1980 and aftclimatic (after climatic) period 1981-2011 by considering distinctly abrupt shift of precipitation regime in the late 1970s across YRB. And the Mann-Kendall trend test is adopted to conduct trend analysis during pre- and aftclimatic periods, respectively, for the purpose of exploring possible increasing/decreasing patterns in precipitation extremes. The results indicate that the increasing trends for return values during aftclimatic period change significantly in time and space in terms of different magnitudes of extreme precipitation, while the stations with significantly positive trends are mainly distributed in the vicinity of the mainstream and major tributaries as well as large lakes, this would result in more tremendous flood disasters in the mid-lower reaches of YRB, especially in southeast coastal regions. The increasing/decreasing linear trends based on annual maximum precipitation are also investigated in pre- and aftclimatic periods, respectively, whereas those changes are not significantly similar to the variations of return values during both subperiods. Moreover, spatiotemporal patterns of precipitation extremes become more uneven and unstable in the second half period over YRB.

  2. 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

  3. 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.

  4. 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:

  5. 长江流域水电工程运行期管理体制的现状%Management System Status Quo during Water Conservancy and Hydropower Engineering Operation Period in Yangtze River Basin

    Institute of Scientific and Technical Information of China (English)

    金影

    2011-01-01

    目前,长江水利电力的发展正处在我国水利电力体制改革和水利电力事业高速前进的机遇期,本文论述了长江流域水电工程1运行期管理体制的现状.%At present, the development of Yangtze river water power is encountering the period of high-speed advance of water conservancy and power system reform, the paper discusses the operation status quo of Yangtze river basin hydropower project management system.

  6. Comparative study on foreign trade development patterns of the Yangtze River Delta and the Pearl River Delta%长三角与珠三角对外贸易发展模式的比较研究

    Institute of Scientific and Technical Information of China (English)

    朱诗娥; 杨汝岱

    2009-01-01

    Based on a massive collection of data,this paper tries to make a detailed comparison between the foreign trade development patterns of two export-oriented regional economies:the Yangtze River Delta and the Pearl River Delta.It is shown that both of the deltas have made spectacular progress in foreign trade development.However,the Yangtze River Delta is catching up with the Pearl River Delta,and China's foreign trade development pattern has changed in recent years from a Pearl River Delta-dominated foreign trade environment to a situation in which the Pearl River Delta and the Yangtze River Delta together dominate China's foreign trade.The primary difierence in the foreign trade development patterns of these two deltas is that foreign trade in the Pearl River Delta relies more on processing trade,while that in the Yangtze River Delta is more government-oriented with special political zones playing a significant role in its foreign trade.%利用相关数据,对长江三角洲经济区和珠江三角洲经济区的对外贸易发展模式进行详尽比较分析.结果显示:两个经济区在对外贸易方面都取得了巨大的成就.然而长二三角作为后发者,正在追赶珠三角,并且中国的外贸发展正在从以珠三角的外贸模式为主转变成两个经济区共同主宰的局面.两个经济区外贸模式的主要区别是:珠三角经济区以加工贸易为主;长三角经济区以政府导向为主,其中政策支持至关重要.

  7. 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.

  8. Impacts of Weather Conditions Modified by Urban Expansion on Surface Ozone:Comparison between the Pearl River Delta and Yangtze River Delta Regions

    Institute of Scientific and Technical Information of China (English)

    WANG Xuemei; CHEN Fei; WU Zhiyong; ZHANG Meigen; Mukul TEWARI; Alex GUENTHER; Christine WIEDINMYER

    2009-01-01

    In this paper,the online weather research and forecasting and chemistry (WRF-Chem) model is used to explore the impacts of urban expansion on regional weather conditions and its implication on surface ozone concentrations over the Pearl River Delta(PRD) and Yangtze River Delta(YRD) regions.Two scenarios of urban maps are used in the WRF-Chem to represent the early 1990s (pre-urbanization) and the current urban distribution in the PRD and the YRD.Month-long simulation results using the above land-use scenarios for March 2001 show that urbanization increases both the day- and night-time 2-m temperatures by about 0.6℃ and 1.4℃,respectively. Daytime reduction in the wind speed by about 3.0 m s-1 is larger than that for the nighttime (0.5 to 2 m s-1).The daytime increase in the PBL height (>200 m) is also larger than the nighttime (50-100 m).The meteorological conditions modified by urbanization lead to detectable ozone-concentration changes in the PRD and the YRD.Urbanization increases the nighttime surface-ozone concentrations by about 4.7%-8.5% and by about 2.9%-4.2% for the daytime.In addition to modifying individual meteorological variables,urbanization also enhances the convergence zones,especially in the PRD.More importantly,urbanization has different effects on the surface ozone for the PRD and the YRD,presumably due to their urbanization characteristics and geographical locations.Even though the PRD has a smaller increase in the surface temperature than the YRD,it has (a) weaker surface wind speed,(b)smaller increase in PBL heights,and (c) stronger convergence zones.The latter three factors outweighed the temperature increase and resulted in a larger ozone enhancement in the PRD than the YRD.

  9. 长江滩地杨树人工林主伐年龄的研究%A STUDY ON PRINCIPAL FELLING AGE OF POPLAR PLANTATION ON CHANGJIANG RIVER BEACH

    Institute of Scientific and Technical Information of China (English)

    黄庆丰; 孙启祥; 吴泽民; 项艳

    2002-01-01

    The principal felling age of poplar on Changjiang River beach was studied in Nangen forest farm of Huaining County of Anhui Province.Based on beach altitude,the beach was divided into two site conditions:the higher beach(15-16.5m)and lower beach(14-15m).Moder y=a+b lnA was selected as the growth model of poplar plantation.The yield table of poplar plantation was compiled by growth model.At the same time,the assortment yield table of poplar plantation was compiled based on the univariate volume ratio model.According to volume yield table and assortment yield table,the quantitative maturity age both two sites should be 7 years,technical maturity age of match blocks for higher beach and lower beach were 5 years and 6 years respectively.Economic maturity age was 10-13 years for higher beach (P=10%、8%、6%)and 11-12 years for lower beach (P=10%、8%)on the basis of the maximum net present value.In conclusion,according to the three maturity age and management purposes the principal felling age of poplar plantation should be 10-14 years for higher beach and 8-12 years for lower beach.

  10. 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.

  11. 南京长江航运国际物流中心发展研究%Study on Development and Countermeasures Research of Constructing Nanjing Yangtze River International Logistics Center

    Institute of Scientific and Technical Information of China (English)

    胡林凤; 王鹏

    2015-01-01

    Nanjing is an important comprehensive transportation junction and logistics nodes city in China.Port of Nanjing as the destination of ten thousand tons sea vessel entering the river,as the first class port opening door to the outside,and as the internationality,multifunc-tion,integrated main pivotal port in Yangtze River Basin which transfer from river to ocean, she has the foundation and potential to become the Yangtze River international shipping logis-tics center.Under the background of the government to accelerate the development of the Yangtze River Economic Belt,this paper analyzes the challenge and opportunity to construct Nanjing Yangtze River international logistics center,and puts forward some relevant counter-measures and recommendation in order to provide reference to speed up the pace to construct the Nanjing Yangtze River international logistics center.%南京是全国重要的综合交通枢纽和物流节点城市。南京港是万吨级海轮进江的终点和对外开放一类口岸,也是长江流域国际性、多功能、综合型江海转运主枢纽港,具有打造长江航运国际物流中心的基础和潜力。在国家加快推动长江经济带发展背景下,分析了建立南京长江航运国际物流中心的机遇与挑战,提出了相应的对策,以期对加快建立南京长江航运国际物流中心具有一定的指导意义。

  12. 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.

  13. 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.

  14. Transformation Efficiency of Sulfur for a Mulberry Leaf-Silkworm Cocoon System in the Lower-Middle Reaches of the Yangtze River, China

    Institute of Scientific and Technical Information of China (English)

    ZHAO Yan-Wen; HU Zheng-Yi; CAO Zhi-Hong; J. D. BEATON; A. M. HENDERSON; M. X. FAN; XU Cheng-Kai

    2005-01-01

    Cocoon samples were collected from fifty-two mulberry gardens with high, intermediate, and low silkworm cocoon productivities in the lower-middle reaches of the Yangtze River in the six China's provinces of Jiangsu, Jiangxi, Anhui,Fujian, Hunan, and Hubei to determine the transformation efficiency of S from mulberry leaves to silkworm cocoons,and to evaluate the sulfur cycle (uptake and output) in the mulberry leaf-silkworm cocoon system with typical mulberry gardens in the lower-middle reaches of the Yangtze River in China. The transformation efficiency of sulfur (TES) from mulberry leaves into silkworm cocoons in the high-productivity mulberry gardens was significantly lower (P <0.05) than that in the low-productivity gardens. For the high-productivity mulberry gardens the TES from mulberry leaves into the cocoon shells was significantly higher (P <0.05) than that for low-yield mulberry gardens. Producing 1 kg dry cocoon in mulberry gardens required uptake of about 20 g S, however 1 kg of dry cocoon only removed about 4 g S. Therefore,recycling of these organic wastes with silkworm cultivation was important for sulfur balance.

  15. 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.

  16. Moisture Analysis of a Squall Line Case Based on Precipitable Water Vapor Data from a Ground-Based GPS Network in the Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    DING Jincai; YANG Yinming; YE Qixin; HUANG Yan; MA Xiaoxing; MA Leiming; Y.R.GUO

    2007-01-01

    A squall line swept eastward across the area of the Yangtze River Delta and produced gusty winds and heavy rain from the afternoon to the evening of 24 August 2002. In this paper, the roles of moisture in the genesis and development of the squall line were studied. Based on the precipitable water vapor (PWV) data from a ground-based GPS network over the Yangtze River Delta in China, plus data from a Pennsylvania State University/National Atmospheric Center (PSU/NCAR) mesoscale model (MM5) simulation, initialized by three-dimensional variational (3D-VAR) assimilation of the PWV data, some interesting features are revealed. During the 12 hours prior to the squall line arriving in the Shanghai area, a significant increase in PWV indicates a favorable moist environment for a squall line to develop. The vertical profile of the moisture illustrates that it mainly increased in the middle levels of the troposphere, and not at the surface. Temporal variation in PWV is a better precursor for squall line development than other surface meteorological parameters. The characteristics of the horizontal distribution of PWV not only indicated a favorable moist environment, but also evolved a cyclonic wind field for a squall line genesis and development. The "+2 mm" contours of the three-hourly PWV variation can be used successfully to predict the location of the squall line two hours later.

  17. 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.

  18. PM2.5 in the Yangtze River Delta, China: Chemical compositions, seasonal variations, and regional pollution events.

    Science.gov (United States)

    Ming, Lili; Jin, Ling; Li, Jun; Fu, Pingqing; Yang, Wenyi; Liu, Di; Zhang, Gan; Wang, Zifa; Li, Xiangdong

    2017-04-01

    Fine particle (PM2.5) samples were collected simultaneously at three urban sites (Shanghai, Nanjing, and Hangzhou) and one rural site near Ningbo in the Yangtze River Delta (YRD) region, China, on a weekly basis from September 2013 to August 2014. In addition, high-frequency daily sampling was conducted in Shanghai and Nanjing for one month during each season. Severe regional PM2.5 pollution episodes were frequently observed in the YRD, with annual mean concentrations of 94.6 ± 55.9, 97.8 ± 40.5, 134 ± 54.3, and 94.0 ± 57.6 μg m(-3) in Shanghai, Nanjing, Hangzhou, and Ningbo, respectively. The concentrations of PM2.5 and ambient trace metals at the four sites showed clear seasonal trends, with higher concentrations in winter and lower concentrations in summer. In Shanghai, similar seasonal patterns were found for organic carbon (OC), elemental carbon (EC), and water-soluble inorganic ions (K(+), NH4(+), Cl(-), NO3(-), and SO4(2-)). Air mass backward trajectory and potential source contribution function (PSCF) analyses implied that areas of central and northern China contributed significantly to the concentration and chemical compositions of PM2.5 in Shanghai during winter. Three heavy pollution events in Shanghai were observed during autumn and winter. The modelling results of the Nested Air Quality Prediction Modeling System (NAQPMS) showed the sources and transport of PM2.5 in the YRD during the three pollution processes. The contribution of secondary species (SOC, NH4(+), NO3(-), and SO4(2-)) in pollution event (PE) periods was much higher than in BPE (before pollution event) and APE (after pollution event) periods, suggesting the importance of secondary aerosol formation during the three pollution events. Furthermore, the bioavailability of Cu, and Zn in the wintertime PM2.5 samples from Shanghai was much higher during the pollution days than during the non-pollution days.

  19. 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

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

    Directory of Open Access Journals (Sweden)

    X. Fu

    2013-08-01

    Full Text Available During 1 to 6 May 2011, a dust event was observed in the Yangtze River Delta region (YRD. The highest PM10 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 on deposition and photochemistry. The threshold friction velocity for loose smooth surface in the dust model was revised based on Chinese data to improve the model performance. The comparison between predictions and observations indicates the revised model can reproduce the transport and pollution of the event. The simulation results show that the dust event was affected by formation and transport of Mongolian cyclone and cold air. Totally about 695 kt dust particles (PM10 were emitted in Xinjiang Province and Mongolia during 28 to 30 April, the dust band swept northern, eastern China and then arrived in the YRD region on 1 May 2011. The transported dust particles increased the mean surface layer concentrations of PM10 in the YRD region by 372% during 1 to 6 May and the impacts weakened from north to south due to the removal of dust particles along the path. Accompanied by high PM concentration, 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. These deposited particles are very harmful because of their impacts on urban environment as well as air quality and human health when resuspending in the atmosphere. Due to the impacts of mineral dust on atmospheric photolysis, the concentrations of O3 and OH were reduced by 1.5% and 3.1% in the whole China, and by 9.4% and 12.1% in the YRD region, respectively. The work of this manuscript is meaningful for understanding the dust emissions in China as well as for the application of CMAQ in Asia. It is also

  1. Spatial and temporal trends of reference crop evapotranspiration and its influential variables in Yangtze River Delta, eastern China

    Science.gov (United States)

    Xu, Yu; Xu, Youpeng; Wang, Yuefeng; Wu, Lei; Li, Guang; Song, Song

    2016-09-01

    Reference crop evapotranspiration (ETo) is one of the most important links in hydrologic circulation and greatly affects regional agricultural production and water resource management. Its variation has drawn more and more attention in the context of global warming. We used the Penman-Monteith method of the Food and Agriculture Organization, based on meteorological factors such as air temperature, sunshine duration, wind speed, and relative humidity to calculate the ETo over 46 meteorological stations located in the Yangtze River Delta, eastern China, from 1957 to 2014. The spatial distributions and temporal trends in ETo were analyzed based on the modified Mann-Kendall trend test and linear regression method, while ArcGIS software was employed to produce the distribution maps. The multiple stepwise regression method was applied in the analysis of the meteorological variable time series to identify the causes of any observed trends in ETo. The results indicated that annual ETo showed an obvious spatial pattern of higher values in the north than in the south. Annual increasing trends were found at 34 meteorological stations (73.91 % of the total), which were mainly located in the southeast. Among them, 12 (26.09 % of the total) stations showed significant trends. We saw a dominance of increasing trends in the monthly ETo except for January, February, and August. The high value zone of monthly ETo appeared in the northwest from February to June, mid-south area from July to August, and southeast coastal area from September to January. The research period was divided into two stages—stage I (1957-1989) and stage II (1990-2014)—to investigate the long-term temporal ETo variation. In stage I, almost 85 % of the total stations experienced decreasing trends, while more than half of the meteorological stations showed significant increasing trends in annual ETo during stage II except in February and September. Relative humidity, wind speed, and sunshine duration were

  2. 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

  3. Natural emissions under future climate condition and their effects on surface ozone in the Yangtze River Delta region, China

    Science.gov (United States)

    Xie, Min; Shu, Lei; Wang, Ti-jian; Liu, Qian; Gao, Da; Li, Shu; Zhuang, Bing-liang; Han, Yong; Li, Meng-meng; Chen, Pu-long

    2017-02-01

    The natural emissions of ozone precursors (NOx and VOCs) are sensitive to climate. Future climate change can impact O3 concentrations by perturbing these emissions. To better estimate the variation of natural emissions under different climate conditions and understand its effect on surface O3, we model the present and the future air quality over the Yangtze River Delta (YRD) region by running different simulations with the aid of the WRF-CALGRID model system that contains a natural emission module. Firstly, we estimate the natural emissions at present and in IPCC A1B scenario. The results show that biogenic VOC emission and soil NOx emission over YRD in 2008 is 657 Gg C and 19.1 Gg N, respectively. According to climate change, these emissions in 2050 will increase by 25.5% and 11.5%, respectively. Secondly, the effects of future natural emissions and meteorology on surface O3 are investigated and compared. It is found that the variations in meteorological fields can significantly alter the spatial distribution of O3 over YRD, with the increases of 5-15 ppb in the north and the decreases of -5 to -15 ppb in the south. However, only approximately 20% of the surface O3 increases caused by climate change can be attributed to the natural emissions, with the highest increment up to 2.4 ppb. Finally, Ra (the ratio of impacts from NOx and VOCs on O3 formation) and H2O2/HNO3 (the ratio between the concentrations of H2O2 and HNO3) are applied to study the O3 sensitivity in YRD. The results show that the transition value of H2O2/HNO3 will turn from 0.3 to 0.5 in 2008 to 0.4-0.8 in 2050. O3 formation in the YRD region will be insensitive to VOCs under future climate condition, implying more NOx need to be cut down. Our findings can help us understand O3 variation trend and put forward the reasonable and effective pollution control policies in these famous polluted areas.

  4. Application of Geotextiles in Jiepai Waterway Regulation Engineering of the Yangtze River%土工织物在长江界牌航道整治工程中的应用

    Institute of Scientific and Technical Information of China (English)

    李国祥; 胡义龙

    2001-01-01

    通过长江界牌航道整治工程实例介绍土工织物在航道整治工程中的应用情况。%Based on the practical example of Jiepai Waterway Regulation Engineering of the Yangtze River, it introduces the application of geotextile in waterway regulation engineering.

  5. 长三角高职类物流人才核心竞争力研究%Research of Core Competitiveness of Higher Vocational Logistics Talents in Yangtze River Delta Region

    Institute of Scientific and Technical Information of China (English)

    林小芳; 杨玉玉; 王海船; 夏慧玲

    2011-01-01

    长三角地区由于其地理位置显要,交通设施便利,经济发展水平高等特点,其物流优势显现.与其他经济圈不同,长三角以民营企业居多.而企业性质不同,对物流人才的基本素质要求也是不同的.笔者结合长三角物流行业特点,在调查分析的基础上,探讨长三角高职类物流人才核心竞争力,为高职院校物流人才培养方向提供一定的依据.%Due to the characteristics of Yangtze River Delta region, such as prominent geography location, convenient traffic facilities and economic development with high level, its logistics advantage is appearing. Compared to other economic circle, there are many private enterprises in Yangtze River Delta region. However, different nature of enterprise has different requirements for basic quality of logistics talents. Combined with the characteristics of logistics industry in Yangtze River Delta region and based on the investigation and analysis, the author discusses core competitiveness of higher vocational logistics talents in Yangtze River Delta region so as to provide basis for the training direction of logistics talents in higher vocational colleges.

  6. Composition and flux of nurtients transport to the Changjiang Estuary

    Institute of Scientific and Technical Information of China (English)

    ZHANGShen; JIHongbing; YANWeijin; DUANShuiwang

    2003-01-01

    Based on the results of water sample measurements of nutrient concentrations at the Datong Station of Changjiang River from 1998 to 1999,combined with historiceal data of water quality,seasonal variations of nutrient concentrations and nutrient transports are discussed.Tthe following results have been obtained:(1)the fluxes of the nitrate nitrogen,ammonium nitrogen and nitrite nitrogen increased by time0series from 1962 to 1990,even if runoff volume had a little variation;(2)the concentrations and fluxes of the dissolved inorganic nitrogen (DIN)and dissolved inorganic phosphorus (DIP)increased notably with time,but those of th dissolved silicon(DSI)decreased pronouncedly,and (3) the concentrations and fluxes changed synchronously with time between the Datong Station and the Changjiang Estuary.

  7. 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

  8. The Inter-city Rail Transit Planning Scheme for Jiangsu Cities Complex along Yangtze River%江苏省沿江城市群城际轨道交通线网规划方案研究

    Institute of Scientific and Technical Information of China (English)

    邓振林

    2012-01-01

    城际轨道交通的规划建设是城市群发展的必然要求,江苏沿江城市群是我国城市化进程过程中重点发展的区域。根据沿江地区城市群的特征,把沿江地区城际轨道交通线网分为主骨架城际网和都市圈城际网两个层次进行规划,重点研究沿江地区都市圈内部中心城市之间以及中心城市与中小城市之间的城际轨道交通通勤线网。%Plan and construction of intercity rail transit is an inevitable demand for the development of urban complexes to meet the requirements of increasing demand of passengers and freight traffic.Jiangsu cities complex along Yangtze River is a key concern during the process of China’s urbanization process.Based on the economic characteristics of cities complex along Yangtze River,the urban rain transit network planning along Yangtze River is classified into two levels: backbone inter-city network and metropolitan area inter-city network,key research is carried out on the intercity rail way network among the center cities and between the central city and medium and small city of the metropolitan area along Yangtze River.This paper is designed to put forward a more reasonable network planning of inter-city rail transit for Jiangsu cities complex along Yangtze River,but also provides some reference for the inter-city rail transit network planning of other urban agglomerations,which has a positive theoretical and practical significance.

  9. 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.

  10. 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.

  11. Characteristics of C and O stable isotope in otolith of juvenile Coilia nasus from the Changjiang River Estuary%长江口刀鲚幼鱼耳石碳、氧同位素特征初报

    Institute of Scientific and Technical Information of China (English)

    姜涛; 刘洪波; 杨健

    2015-01-01

    为了解长江口刀鲚(Coilia nasus)耳石中碳、氧稳定同位素的特征及其可能反映出的生态学意义,作者利用稳定同位素质谱分析技术,首次对长江口刀鲚幼鱼的耳石进行碳、氧稳定同位素的初步研究。结果显示,δ13C和δ18O分别为–12.1±1.8(‰VPDB)和–7.9±1.2(‰VPDB),总体上δ13C波动较大,而δ18O波动较小。基于个体的δ13C和δ18O散点分布可将本研究中的刀鲚归为两个组,可能起源于长江中两个不同孵化场水域的群体,其中δ18O显示出两组刀鲚所经历环境积温上的差异,反映出两者起源水域温度环境的不同;而δ13C的差异说明两组刀鲚在饵料组成上的有所差异。%For better understanding of the characteristics of stable carbon (δ13C) and oxygen (δ18O) isotopes in the otolith ofCoilia nasusand the possible ecological significances, the analysis of otolith stable isotope ratios ofδ13C andδ18O was conducted using an isotope ratio mass spectrometry onC. nasus juveniles collected from the Chang-jiang River Estuary. The otolith revealedδ13C andδ18O values of –12.1±1.8(‰VPDB) and –7.9±1.2 (‰VPDB), respectively. Unlikeδ18O,δ13C generally varied in a relatively wide range. Two groups of the fish could be sepa-rated based on scattered distribution by otolithδ13C andδ18O values of allC. nasus individuals in the present study, suggesting possible different natal origins (i.e. spawning/nursery areas) in the Changjiang River. The different en-vironments with different water temperature and food organism composition might be experienced by the two groups ofC. nasus fish.

  12. 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

  13. Human Capital Accumulation and Economic Growth in City Region along the Changjiang River in Anhui%皖江城市带的人力资本积累与经济增长

    Institute of Scientific and Technical Information of China (English)

    张小雪; 李诗争

    2014-01-01

    Average years of education of city region along the Changjiang River in Anhui from 2008 to 2011 indicated that human capital accumulation has grown up caused by the undertaking industrial trans-fer strategy,but huge gap also exist in the groups. The panel-date model analysis showed that the human capital has almost the same impact on the output growth as the physical capital. It indicated that the differences of output growth among the 8 cities are most caused by the technology growth gap in the pa-per. Cities own more human capital gain greater contribution of technology to the output growth.%用受教育年限法对皖江城市带各市人力资本积累的总量和结构现状进行分析,结论表明承接产业转移战略实施后示范区人力资本积累整体水平有所提升但呈现出两级分化趋势。面板数据模型分析表明人力资本、物质资本的产出弹性分别为0.82和0.85,二者对产出增长的拉动作用不相上下;面板分析还表明示范区内部各市产出增长的结构性差异主要体现在技术要素的作用上,而人力资本积累水平较高的城市其技术要素对产出增长的作用也越大。

  14. Distribution of heavy metals in an incineration system of solid wastes in the Three-Gorges region of the Yangtze River

    Institute of Scientific and Technical Information of China (English)

    HUANG Chuan; WANG Li'ao; CHEN Gangcai; LUO Yu; ZHANG Jun; CUI Zhiqiang

    2008-01-01

    On the basis of investigations on the composition and contents of heavy metals in the domestic refuse in the Three-Gorges region of the Yangtze River, in combination with the experimental results, this paper deals with the distribution rule of heavy metals in the various compartments of an incineration system: leachate pool, fly ash and residue. It is concluded that in the leachate pool heavy metals should not be neglectable since about 30% of Pb and 10% of Cr are leached here; in the incineration system, above 74% of Cr, As and Pb exists in residue; above 96% of Hg exists in fly ash and the contents of Cd in fly ash are close to those of residue. It is also concluded that the physical conditions of incineration have a significant influence on the distribution of heavy metals in the incineration system.

  15. Dynamics of spatial clustering of schistosomiasis in the Yangtze River Valley at the end of and following the World Bank Loan Project.

    Science.gov (United States)

    Hu, Yi; Xiong, Chenglong; Zhang, Zhijie; Luo, Can; Ward, Michael; Gao, Jie; Zhang, Lijuan; Jiang, Qingwu

    2014-06-01

    The 10-year (1992-2001) World Bank Loan Project (WBLP) contributed greatly to schistosomiasis control in China. However, the re-emergence of schistosomiasis in recent years challenged the long-term progress of the WBLP strategy. In order to gain insight in the long-term progress of the WBLP, the spatial pattern of the epidemic was investigated in the Yangtze River Valley between 1999-2001 and 2007-2008. Two spatial cluster methods were jointly used to identify spatial clusters of cases. The magnitude and number of clusters varied during 1999-2001. It was found that prevalence of schistosomiasis had been greatly reduced and maintained at a low level during 2007-2008, with little change. Besides, spatial clusters most frequently occurred within 16 counties in the Dongting Lake region and within 5 counties in the Poyang Lake region. These findings precisely pointed out the prior places for future public health planning and resource allocation of schistosomiasis.

  16. Understanding the external pressure and behavior of commercial banks' environmental risk management: an empirical study undertaken in the Yangtze River delta of China.

    Science.gov (United States)

    Liu, Yong; Lin, Zhongguo

    2014-04-01

    The present study employed a quantitative survey to ascertain whether the external pressure of environmental risk management (ERM) on commercial banks was a contributing factor to their ERM behavior. Data was obtained using questionnaires from 204 branches of commercial banks located in the Yangtze River Delta of China. The relationship between external pressure and behavior was tested using a linear structural relations model through path analysis. The results revealed that external pressure of ERM was significantly and positively related to the behavior and that pressure from governmental regulations was the most important contributing factor in the passive feedback behavior and preventive behavior of commercial banks. The pressure from markets was the most important contributing factor in banks' active participation behavior; the pressure from community and NGOs was the most important contributing factor in their enthusiastic behavior.

  17. 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)

    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

  18. 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.

  19. 长三角地区冬季供暖模式选择研究%Heating Mode Selection of Yangtze River Delta Region in Winter

    Institute of Scientific and Technical Information of China (English)

    孙仲武

    2012-01-01

    通过对国内现有供暖方式的优缺点对照分析,提出长三角地区供暖方案选择的原则.水源、地热源、空气源与太阳能相结合的多元化供暖模式将会是发展方向,供暖末端系统宜选用低温热水地板辐射或热风采暖系统.%Baaed on analyzing the advantages and disadvantages of existing domestic heating mode, the paper proposed the selection principle of healing mode in Yangtze River Delta region. The heating mode of combining with the water, geothermal heating, air source and solar will be the development direction of heating system. The end of heating system can use low temperature hot water floor radiation or hot air heating system.

  20. Synchrotron X-ray microfluorescence measurement of metal distributions in Phragmites australis root system in the Yangtze River intertidal zone

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Huan; Zhang, Weiguo; Qian, Yu; Liu, Wenliang; Yu, Lizhong; Yoo, Shinjae; Wang, Jun; Wang, Jia-Jun; Eng, Christopher; Liu, Chang-Jun; Tappero, Ryan

    2016-06-15

    This study investigates the distributions of Br, Ca, Cl, Cr, Cu, K, Fe, Mn, Pb, Ti, V and Zn inPhragmites australisroot system and the function of Fe nanoparticles in scavenging metals in the root epidermis using synchrotron X-ray microfluorescence, synchrotron transmission X-ray microscope measurement and synchrotron X-ray absorption near-edge structure techniques. The purpose of this study is to understand the mobility of metals in wetland plant root systems after their uptake from rhizosphere soils.Phragmites australissamples were collected in the Yangtze River intertidal zone in July 2013. The results indicate that Fe nanoparticles are present in the root epidermis and that other metals correlate significantly with Fe, suggesting that Fe nanoparticles play an important role in metal scavenging in the epidermis.

  1. Study on“safe speed” in Jiangsu Section of the Yangtze River%长江江苏段“安全航速”的探究

    Institute of Scientific and Technical Information of China (English)

    熊峰

    2015-01-01

    Jiangsu section of the Yangtze River is narrow ,and the shipping environment is complex .According to COLREGS and domestic regulations ,based on different channel ? environment ,this essay proposes that the safe speed and measures should be accurately used , which is one of the most effective ways of avoiding ? the risk of ? navigation .%长江江苏段航道狭窄、航行环境复杂。根据国际规则和国内法规要求,针对航道环境不同,提出海轮正确运用安全航速方法和措施,是规避航行风险的最有效措施之一。

  2. 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).

  3. 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.

  4. Performance in Grain Yield and Physiological Traits of Rice in the Yangtze River Basin of China During the Last 60 yr

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hao; CHEN Ting-ting; LIU Li-jun; WANG Zhi-qin; YANG Jian-chang; ZHANG Jian-hua

    2013-01-01

    Knowledge on the performance in grain yield and physiological traits is essential to understand the main yield-limiting factor and make strategies for breeding and crop management in rice (Oryza sativa L.). This study investigated the changes in grain yield and associated physiological traits of rice in the Yangtze River Basin of China during the last 60 yr. Thirteen mid-season indica and 12 japonica rice cultivars that were popularly used were grown in the field in 2008 and 2009. The grain yield and yield components, biomass, leaf area, leaf photosynthesis, root oxidation activity, and harvest index were examined. The results showed that grain yield and grain yield per day have progressively increased during the years and such increases are mainly attributed to the expanded sink size as a result of more spikelets per panicle, especially for the case of super rice. Both biomass and harvest index were increased with the improvement of cultivars. Increase in biomass for modern rice cultivars was associated with an enhancement of leaf area and photosynthesis, root dry weight, and root oxidation activity, although the indica super rice cultivars showed a lower leaf photosynthetic rate and root oxidation activity than the semi-dwarf cultivars during the grain filling period. Both indica and japonica super rice cultivars exhibited a low percentage of filled grains, which may limit their great yield potential. All the data suggested that grain yield have been substantially improved during the 60 yr of rice breeding in the Yangtze River Basin. Expanded sink size, increased dry matter production and harvest index, and enhanced leaf area and photosynthesis, root dry weight, and root oxidation activity contribute to the improvement in grain yield. Increase in filling efficiency could realize the great yield potential in super rice.

  5. Phytolith records of the climate change since the past 15000 years in the middle reach of the Yangtze River in China

    Institute of Scientific and Technical Information of China (English)

    Yansheng GU; Hanlin WANG; Xianyu HUANG; Hongxia PENG; Junhua HUANG

    2012-01-01

    Based on 14C dating and core sediments survey,phytolith records are employed to reconstruct paleovegetation and paleoclimate in the Jianghan Plain in the middle reach of the Yangtze River.Phytoliths identified are assigned into 21well-described morphotypes and divided into four groups (Poaceae,fern,coniferous and broad-leaved).The phytolith assemblages together with warmth index (Iw) are divided into 18 ecological zones,which reflect a complete vegetation history related to climate change in the middle reach of the Yangtze River during the past 15000 years.On the basis of the correlation ofphytolith records with the paleoclimatic indicators from stalagmite,peatland,North Atlantic deep-sea sediments,Loess Plateau of Central China,and Arabic Sea sediments,eight climatic phases are identified included Last Glacial Maximum (LGM) (20-14.8 cal kaBP),Last Deglaciation (LDG) (14.8-11.9cal kaBP),low-temperature phase in the Early Holocene (11.9-8 cal kaBP),Holocene Optimum (8-4.9cal kaBP),Holocene Katathermal (4.9-1.1cal kaBP),Medieval Warmth Period (MWP) (1.1-0.7 cal kaBP),Little Ice Age (LIA) (0.7-0.15 cal kaBP),and Modem Warming (0.15 cal kaBP-present).Climatic events such as Bolling-Allerod warm intervals,Older Dryas,Inter-Allerod Cold Period,and Younger Dryas,and eight Holocene Bond events (B1-8) have been identified since the LDG.Our results demonstrate that the evolution of the climate in the research area has a strong link with the Indian Summer Monsoon (SW Monsoon),Asian Summer Monsoon (SE Monsoon),and Holocene events in North Atlantic simultaneously,which might indicate that solar variability affects the Earth surface climate system at the centennial and millennial scales.

  6. 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.

  7. Phytolith records of the climate change since the past 15000 years in the middle reach of the Yangtze River in China

    Science.gov (United States)

    Gu, Yansheng; Wang, Hanlin; Huang, Xianyu; Peng, Hongxia; Huang, Junhua

    2012-03-01

    Based on 14C dating and core sediments survey, phytolith records are employed to reconstruct paleovegetation and paleoclimate in the Jianghan Plain in the middle reach of the Yangtze River. Phytoliths identified are assigned into 21 well-described morphotypes and divided into four groups (Poaceae, fern, coniferous and broad-leaved). The phytolith assemblages together with warmth index ( I w) are divided into 18 ecological zones, which reflect a complete vegetation history related to climate change in the middle reach of the Yangtze River during the past 15000 years. On the basis of the correlation of phytolith records with the paleoclimatic indicators from stalagmite, peatland, North Atlantic deep-sea sediments, Loess Plateau of Central China, and Arabic Sea sediments, eight climatic phases are identified included Last Glacial Maximum (LGM) (20-14.8 cal kaBP), Last Deglaciation (LDG) (14.8-11.9 cal kaBP), low-temperature phase in the Early Holocene (11.9-8 cal kaBP), Holocene Optimum (8-4.9 cal kaBP), Holocene Katathermal (4.9-1.1 cal kaBP), Medieval Warmth Period (MWP) (1.1-0.7 cal kaBP), Little Ice Age (LIA) (0.7-0.15 cal kaBP), and Modern Warming (0.15 cal kaBP — present). Climatic events such as Bolling-Allerod warm intervals, Older Dryas, Inter-Allerod Cold Period, and Younger Dryas, and eight Holocene Bond events (B1-8) have been identified since the LDG. Our results demonstrate that the evolution of the climate in the research area has a strong link with the Indian Summer Monsoon (SW Monsoon), Asian Summer Monsoon (SE Monsoon), and Holocene events in North Atlantic simultaneously, which might indicate that solar variability affects the Earth surface climate system at the centennial and millennial scales.

  8. 长江流域水资源综合管理探讨%Discussion on integrated water resources management in Yangtze River Basin

    Institute of Scientific and Technical Information of China (English)

    王海伟

    2014-01-01

    为适应中央生态文明建设、国家经济转型升级、实行最严格水资源管理制度和深化水利改革等国家与行业发展的新形势及对水资源管理的新要求,在总结长江流域取水许可管理、水资源配置和调度管理、水资源监测评估、流域最严格水资源管理制度试点等工作的基础上,分析了长江流域水资源管理面临的形势和存在的突出问题,结合长江流域近期水资源管理的总体思路,提出了推进流域水资源综合管理的建议。%For adapting to new requirements of national ecological civilization construction, economic transformation and upgra-ding, implementation of the most stringent water resources management system and deepening the reform of water resources man-agement, on the basis of experience summarization of water resources management of Yangtze River Basin in the aspects of water licensing, water resources allocation and dispatching, water resource monitoring and assessment, pilot implementation of the most stringent water resources management system etc. , the situation of water resources management and the existed prominent prob-lems in the basin are analyzed. With the combination of general strategy for water resources management of the basin in the near future, the suggestions on promoting the integrated management of water resources management of Yangtze River Basin are put forward.

  9. 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.

  10. Coastal Current Systems and the Movement and Expansion of Suspended Sediment from Changjiang River Estuary%近岸流系与长江入海悬浮泥沙输移扩散

    Institute of Scientific and Technical Information of China (English)

    李四海; 恽才兴

    2006-01-01

    通过两年较完整的序列NOAA/AVHRR数据和实测含沙量资料,利用考虑近岸Ⅱ类水体大气校正的泥沙定量反演算法,获得了较高精度的河口高浓度泥沙遥感反演模式;利用泥沙浓度分级图和反映流系特征的温度图象,系统分析了长江口悬浮泥沙扩散途径、范围及其与近岸流系的关系.影响长江入海悬浮泥沙扩散的近岸流系主要包括台湾暖流、黄海混合水、苏北沿岸流及浙江沿岸流等.冬季,近岸流系比较稳定,其配置状况在一定程度上影响着苏北沿岸泥沙流向长江口的扩散,并制约着入海悬浮泥沙的扩散途径;洪季,长江入海径流量是影响悬浮泥沙扩散的重要因子.同时,长江冲淡水、浙江沿岸流共同形成的冷水区与台湾暖流水之间锋面的强度,也对悬浮泥沙和冲淡水的扩散方向和范围有重要影响;春、秋两季入海悬浮泥沙的扩散型式分别向夏、冬季的分布格局过渡.此外,风应力显著影响着浑水区的扩散方向和范围.风浪掀沙引起的河口泥沙再悬浮,可使近岸泥沙扩散范围增大.%This paper, with NOAA/AHHRR data for 2 years, discusses the expanding path and extent of suspended sediment from the Changjiang River, and the relationship between the suspended sediment expanding and coastal current systems by analyzing the thermal infrared imagery with the sediment imagery, which is acquired by correlating the atmosphere corrected AVHRR imagery with in-situ suspended sediment data. The coastal current systems affecting the sediment dispersal mainly include: the Taiwan Warm Current (TWC), the Huanghai Sea Mixed Water (HSMW), North Jiangsu near-shore current, and Zhejiang near-shore current etc. In winter, the current systems are stable. Their distribution affects the sediment from north Jiangsu expanding toward the Changjiang estuary in some degree .The front between Zhejiang coastal current and TWC blocks the expanding of sediment

  11. 长江河口南港采砂对河床稳定性的影响%The Effect of Sand Digging to Bedfrom Stability of the Nangang Channel in the Changjiang River Mouth

    Institute of Scientific and Technical Information of China (English)

    李茂田; 程和琴; 周丰年; 吴敬文; 李伯昌

    2011-01-01

    利用多波束测深及数字高程模型技术发现:南港主槽有若干长50~100m,深3~5m的采砂坑;瑞丰沙体南侧存在高0.5~1.2m,长约1800m的两级陡坎,陡坎下有长1850m、宽400m、体积124.5万立方米的滑坡体.近8年来,瑞丰沙冲刷减少3724万立方米.采砂坑、陡坎与滑坡体形成的主要受采砂及其引起的瑞丰沙顶部水沙通量调整控制,采砂引起瑞丰沙顶部过水断面增加8240m2,涨潮从南小泓分流0.96亿立方米,落潮从南港主槽分流1.43亿立方米.%According to the bed-form data measured by multi-beam echo-sounding system (MBES) and digital elevation model (DEM), this parer is to examine the impacts of pumping-sand on the river bed-form evolution of the Nangang Channel in the Changjiang River mouth. The results is that there were 5 huge sandpits with 50-100m long and 3-5m depth,2 ranges steep ridge with 1800m long and 0.5-1.2m high and 1 huge landslide with 1850m long and 400m wide in Ruifeng shoal edge nearly sandpits in the Nangang Channel ,and the volume of landslide reached 1.245 × 106m3. Furthermore, our data have further demonstrated such bed-from evolutions mainly resulted from human pumping-sand. Reifeng shoal were obviously eroded and the volume decreased 3.724×107m3 recently 8years. It decreased 8240m2 of longitudinal profile area of the middle Ruifeng shoal,and that resulted in water discharge increasing separately 0.966×l08m3 in flood tide and 1.43× 108 m3 in ebb tide.

  12. 长江经济带创新驱动全要素生产率分析∗%Analysis on the Total Factor Productivity of the Yangtze River Economic Belt

    Institute of Scientific and Technical Information of China (English)

    张予川; 石雨晴

    2016-01-01

    This article is based on the panel data comes from 9 provinces and 2 cities of the Yangtze river economic belt in 2008-2014,using Malmquist DEA method to measure the total factor productivity and its decomposition factor of the Yangtze river economic belt innovation drive during the study period . Research shows that:the Yangtze river economic belt of the whole innovation to drive the total factor productivity presents the rising trend,at an annual rate of 7% growth;in nine provinces and 2 cities of the Yangtze river economic belt only the innovation drive total factor productivity in Chongqing is less than 1,regional difference is not1 obvious,and provincial difference is further narrowing;in the factors of the total factor productivity,technical Efficiency Change have the biggest impact on whole Yangtze river economic belt of innovation to drive the total factor productivity. Based on the above research conclusion, this article puts forward some policy implications to prove innovation to drive the total factor productivity of 9 provinces and 2 cities of the Yangtze river economic belt.%文中基于2008~2014年长江经济带9省2市的省际面板数据,运用Malmquist-DEA的方法测算了研究期间长江经济带创新驱动的全要素生产率及其分解因子。研究表明:长江经济带整体的创新驱动全要素生产率呈现上升趋势,以每年7%的速度增长;长江经济带的9省2市中,只有重庆市创新驱动的全要素生产率小于1,地区差异不明显,而且省际差异正在进一步地缩小;全要素生产率的各分解因素中,技术效率变化对长江经济带整体的创新驱动全要素生产率的影响最大。基于以上的研究结论,文中提出了一些有助于进一步提高长江经济带9省2市创新驱动全要素生产率的政策启示。

  13. 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.

  14. The Research on the Influence of the Change of River Discharge at Datong on the Saltwater Intrusion in Yangtze Estuary%上游大通径流量对长江盐水入侵影响研究

    Institute of Scientific and Technical Information of China (English)

    王伟

    2016-01-01

    建立二维盐度数值模型,计算区域包括大通至长江口及其邻近海域,设计高分辨率网格,数值模拟和分析在不同大通流量等级下长江口盐水入侵形势,计算出中小潮期间长江口重要水库取水口处盐度均值为0畅5‰时对应的临界大通流量。利用模型分析长江口盐度场对上游大通流量的敏感性。本文对临界大通流量的计算研究有助于提高预报长江口盐水入侵模型精度,为长江口水库避咸蓄淡提供参考;盐水入侵对流量的敏感性研究可以为改善盐水入侵情况提供技术指导。%Applying the 2D numerical model with high resolution grid , the response of saltwater intrusion in the Yangtze estuary to the change of river discharge at Datong is studied .The calculated domain of the model includes the lower reaches of the Yangtze River from Datong to the Yangtze Estuary and its adjacent sea .Using the model , the critical discharge of Datong corresponding the average salinity of 0.5‰at important reservoirs ’ water inlets is calculated in different tidal pattern .The sensitivity of Yangtze estuary salinity field to the change of upstream dis-charge is analyzed using the model .The critical chase flow computing research helps to improve the precision of the Yangtze estuary saltwater intrusion model prediction , providing a reference for Yangtze estuary avoiding salty for the storage of reservoir .Saltwater intrusion in the discontinuous flow downstream of the sensitivity of the research im-prove estuary salt water intrusion is to the research on the sensitivity of Yangtze estuary salinity field to the change of upstream discharge can provide technical guidance to avoiding saltwater intrusion at Yangtze estuary in dry sea -sons .

  15. 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

  16. 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

  17. 长江口水域悬沙浓度时空变化与泥沙再悬浮%Temporal and spatial changes of suspended sediment concentration and resuspension in the Yangtze River estuary

    Institute of Scientific and Technical Information of China (English)

    陈沈良; 张国安; 杨世伦

    2003-01-01

    A detailed analysis of suspended sediment concentration (SSC) variations over a year period is presented using the data from 8 stations in the Yangtze River estuary and its adjacent waters, together with a discussion of the hydrodynamic regimes of the estuary. Spatially, the SSC from Xuliujing downwards to Hangzhou Bay increases almost constantly, and the suspended sediment in the inner estuary shows higher concentration in summer than in winter, while in the outer estuary it shows higher concentration in winter than in summer, and the magnitude is greater in the outer estuary than in the inner estuary, greater in the Hangzhou Bay than in the Yangtze River estuary.The sediments discharged by the Yangtze River into the sea are resuspended by marine dynamics included tidal currents and wind waves. Temporally, the SSC shows a pronounced neap-spring tidal cycle and seasonal variations. Furthermore, through the analysis of dynamic mechanism, it is concluded that wave and tidal current are two predominant factors of sediment resuspension and control the distribution and changes of SSC, in which tidal currents control neap-spring tidal cycles,and wind waves control seasonal variations. The ratio between river discharge and marine dynamics controls spatial distribution of SSC.

  18. Impacts of climate change on water resources in source regions of Yangtze River and Yellow River%气候变化对长江、黄河源区水资源的影响

    Institute of Scientific and Technical Information of China (English)

    白路遥; 荣艳淑

    2012-01-01

    The characteristics of the climate in the source regions of the Yangtze River and Yellow River were analyzed based on the monthly precipitation and monthly mean temperature at 22 meteorological stations from 1961 to 2010. The difference in the value between precipitation and evaporation was used to represent the water resources, in order to analyze the impacts of climate change on the water resources. The results show that the precipitation, temperature, and evaporation in the source regions of the Yangtze River and Yellow River have changed significantly, especially in the last 20 years, when there were significant increasing trends in these properties. The water resources presented a fluctuating variation in the source region of the Yellow River and increased significantly in the last 10 years in the source region of the Yangtze River. The increase of precipitation can directly lead to the increase of water resources; however, the increasing temperature can lead to high evaporation that would consume more water resources. Therefore, the influences on water resources can be balanced out by the changes of precipitation and temperature, which explains why there is no significant change in the water resources in the source region of the Yellow River. The temperature increased significantly in the last 10 years in the source region of the Yangtze River, causing more glaciers to melt and water resources to increase in the region.%利用1961-2010年长江、黄河源区22个气象站的月降水量和月平均气温资料,分析长江、黄河源区的气候特征,用降水与蒸发的差值作为水资源量的代表,分析了气候变化对水资源的影响.结果表明,长江源区和黄河源区降水、气温和蒸发都有明显变化,尤其是近20年有明显增加趋势,但是两个源区的变化并不一致,黄河源区水资源量一直呈波动变化,而长江源区在最近10多年水资源量有明显增多现象.降水增多可直接增加水资源量,

  19. 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.

  20. Ninth International Symposium on River Sedimentation(Oct.18-12, 2004, Yichang, China)

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    @@ The Ninth International Symposium on River Sedimentation (9th ISRS) has been successfully held on Oct. 18 to 21, 2004 at the site of the partially completed Three Gorges Project on the Yangtze River near Yichang of Hubei Province, China. The Symposium is organized by the Ministry of Water Resources, People's Republic of China (MWR), sponsored by International Research and Training Center on Erosion and Sedimentation (IRTCES), Changjiang River Water Resources Commission (CWRC), China Institute of Water Resources and Hydropower Research (IWHR) and Chinese Hydraulic Engineering Society (CHES). Twenty nine organizations including the United Nations Educational, Scientific and Cultural Organization (UNESCO), International Association of Hydraulic Engineering and Research (IAHR), International Association for Hydrological Sciences (IAHS) and National Natural Science Foundation of China (NSFC) are co-sponsors.

  1. 长三角地区人力资本产出效应对经济增长影响的实证分析%An Empirical Study of the Impact of Human Capital Output Effect on Economic Growth in the Yangtze River Delta

    Institute of Scientific and Technical Information of China (English)

    于潇; 毛雅萍

    2015-01-01

    Since the reform and opening up,tremendous economic development had been achieved in the area of the Yangtze River Delta,but its economic growth has seen a downward trend from 2005.And many experts believe that the extensive eco-nomic growth in the region is coming to its end.In fact,there is a close connection between economic growth and human capital accumulation in the region.In this paper,according to the human capital thought of Schultz and Becker and to deepen the con-notation of human capital investment,a comparison is made between the impact of MRW model -based human capital on eco-nomic growth and that of expanded MRW -based human capital on economic growth.Then,drawing on human capital -related data of Changjiang River Delta,it makes an empirical analysis of the level effect and growth effect of the human capital in this re-gion.The result shows that the economic growth of the entire area is much influenced by material capital and human capital,with the role of the former far greater than that of the latter.%按照 Schultz 和 Becker 的人力资本思想,深化人力资本投资的内涵,对基于 MRW 模型与拓展后的 MRW 模型的人力资本对经济增长影响进行比较,并利用长三角人力资本相关数据对该地区人力资本的水平效应和增长效应进行实证研究。结果表明:整个长三角地区的经济增长,受物资资本和人力资本影响较大,其中,人力资本所发挥的作用远不及物质资本所发挥的作用。

  2. Risk Analysis and Prevention Measures of Yangtze River Delta Small and Medium-sized Enterprises Export%长三角中小企业出口风险分析及防范措施

    Institute of Scientific and Technical Information of China (English)

    刘欢

    2012-01-01

    As the leader of China's economic development, the development of SMEs in Yangtze River Delta were concerned at home and abroad. Proceeding from the export problems of SMEs in Yangtze River Delta, the article makes risk attribution analysis, and suggests measures to respond to risk, which has practical significance to the development of current foreign trade export enterprise.%长三角地区作为中国经济发展的领跑者,中小企业的发展受到了国内外的广泛关注.文章从长三角地区中小企业外贸出口问题出发,对出口风险进行了归因分析,并提出了应对风险的措施,对当前外贸出口企业的发展有一定的现实意义.

  3. 安庆沿江湖泊湿地保护管理对策%Strategies for Conservation and Management of the Lake Wetlands along Yangtze River in Anqing City

    Institute of Scientific and Technical Information of China (English)

    王康明

    2015-01-01

    本文介绍了安庆沿江湖泊湿地的基本情况、生态价值,在指出安庆沿江湖泊湿地保护当前面临的主要问题的基础上,提出了加强湖泊湿地保护管理的对策,旨在进一步促进沿江湖泊湿地保护管理工作。%In this paper, the basic information and ecological value of the lake wetlands along Yangtze River in Anqing City were introduced. And the main existing problems in the conservation of these wetlands along Yangtze River in Anqing were pointed out. Some strategies to strengthen the conservation and management of the lake wetlands were put forward with the aim of promoting their conservation and management.

  4. Spatial Distribution Characteristics of Hydrogen and Oxygen Isotopes in the Mainstream of Yangtze River%长江干流水体氢氧同位素空间分布特征

    Institute of Scientific and Technical Information of China (English)

    陈新明; 甘义群; 刘运德; 李小倩; 余婷婷

    2011-01-01

    This paper analyses the spatial variation characteristics of hydrogen and oxygen isotopes and deuterium excess parameters, and studies the relationship of hydrogen and oxygen isotopes between water of Yangtze River and of precipitation based on the data of hydrogen and oxygen isotopes of Yangtze River from Chongqing to Shanghai. The results show that hydrogen and oxygen isotopes present different characteristics along Yangtze River due to influences of water recharge sources, continental effect and altitude effect. δ18O and δD are more positive from Chongqing to Shanghai along the Yangtze River and most of the deuterium excess parameters(d value) of the upper reaches of Yangtze River are smaller than those of global meteoric water line with significant variation ranging from 3. 0‰ to 12. 2‰. In contrast, all the deuterium excess parameters of the mid-lower reaches of Yangtze River are approximately 10‰ and the evaporation and condensation of lakes near the Yangtze River have caused δ18 O and SD to be more positive than that of the Yangtze River.%采用热转换元素分析同位素比值质谱法(TC/EA-IRMS)对重庆至上海段长江干流的氢氧同位素进行了监测,分析了该段长江水的氢氧同位素和氘过量参数的空间变化规律,并探讨了δ(18O)和δ(D)与大气降水氢氧同位素的关系.结果表明:长江干流不同地段水体受补给来源、大陆效应、高程效应等因素影响,其水体氢氧同位素也呈现出不同的特征.沿径流方向长江干流水体的δ(18O)和δ(D)沿程逐渐偏正.长江干流上游重庆至宜昌段的氘过量参数大部分小于全球大气降水线的氘过量参数10‰,且波动较大,达3.0‰~12