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1.
M. Kummu S. Tes S. Yin P. Adamson J. Józsa J. Koponen J. Richey J. Sarkkula 《水文研究》2014,28(4):1722-1733
The Tonle Sap Lake of Cambodia is the largest freshwater body of Southeast Asia, forming an important part of the Mekong River system. The lake has an extremely productive ecosystem and operates as a natural floodwater reservoir for the lower Mekong Basin, offering flood protection and assuring the dry season flow to the Mekong Delta. In light of the accelerating pace of water resources development within the Mekong Basin and the anticipation of potentially significant hydrological impacts, it is critical to understand the overall hydrologic regime of Tonle Sap Lake. We present here a detailed water balance model based on observed data of discharges from the lake's tributaries, discharge between Mekong and the lake through the Tonle Sap River, precipitation, and evaporation. The overland flow between the Mekong and lake was modelled with the EIA 3D hydrodynamic model. We found that majority (53.5%) of the water originates from the Mekong mainstream, but the lake's tributaries also play an important role contributing 34% of the annual flow, while 12.5% is derived from precipitation. The water level in the lake is mainly controlled by the water level in the Mekong mainstream. The Tonle Sap system is hence very vulnerable, from a water quantity point of view, to possible changes in the Mekong mainstream and thus, development activities in the whole Mekong basin. From a biogeochemical point of view, the possible changes in the lake's own catchment are equally important, together with the changes in the whole Mekong Basin. Based on our findings, we recommend of continuing the monitoring programmes in lake's tributaries and urgently starting of groundwater measurement campaign within the floodplain, and including the groundwater modelling to be part of the hydrodynamic models applied for the lake. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
2.
Keisuke Hoshikawa Yoichi Fujihara Sokly Siev Seiya Arai Takashi Nakamura Hideto Fujii Ty Sok Chihiro Yoshimura 《水文研究》2019,33(21):2745-2758
Large, shallow‐water lakes located on floodplains play an important role in creating highly productive ecosystems and are prone to high concentrations of suspended solids due to sediment resuspension. In this study, the aim was to determine the dominant processes governing the total suspended solid (TSS) concentration at the water surface in Tonle Sap Lake, Cambodia, which is a large, shallow‐water lake. Satellite remotely sensed daily reflectance data from 2003 to 2017 were used. Seasonal changes in TSS concentration indicated that bottom sediment resuspension during dry seasons was mostly caused by wind and the TSS concentration was closely correlated with the water depth of the lake. The TSS concentration during flood periods was controlled by both wind and inflow currents from the Tonle Sap River. Additionally, we confirmed that surface/subsurface flow with a low TSS concentration from forests on the floodplain lowered the TSS concentration year round, except during August and September. This fact implied that the floodplain forest area decrease may increase the lake TSS concentration. An analysis of the long‐term changes in TSS indicated that a decrease in the water level during flood periods resulted in the high TSS concentrations observed during the subsequent dry periods. Therefore, climate change and water resource development, which are likely to cause water level reductions in the Mekong River during flood periods, may increase the TSS concentration in Tonle Sap Lake, particularly during the dry season. 相似文献
3.
The Mekong Basin in southeast Asia is facing rapid development, impacting its hydrology and sediment dynamics. Although the understanding of the sediment transport rates in the Mekong is gradually growing, the sediment dynamics in the lower Mekong floodplains (downstream from Kratie) are poorly understood. The aim of this study is to conduct an analysis to increase the understanding of the sediment dynamics at the Chaktomuk confluence of the Mekong River, and the Tonle Sap River in the Lower Mekong River in Cambodia. This study is based on the data from a detailed field survey over the three hydrological years (May 2008–April 2011) at the two sites (the Mekong mainstream and the Tonle Sap River) at the Chaktomuk confluence. We further compared the sediment fluxes at Chaktomuk to an upstream station (i.e. Mukdahan) with longer time series. Inflow sediment load towards the lake was lower than that of the outflow, with a ratio on average of 84%. Although annually only a small amount of sediment load from the Tonle Sap contributes to the delta (less than 15%), its share is substantial during the February–April period. The annual sediment load transport from the confluence to the delta in 2009 and 2010 accounted for 54 and 50 Mt, respectively. This was on average only 55% of the sediment fluxes measured at Mukdahan, a more upstream station. Furthermore when compared to sediment loads further downstream at the Cambodia–Vietnam border, we found that the suspended sediment flux continued to decline towards the South China Sea. Our findings thus indicate that the sediment load to the South China Sea is much lower than the previous estimate 150–160 Mt/yr. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
4.
Aifang Chen Junguo Liu Matti Kummu Olli Varis Qiuhong Tang Ganquan Mao Jie Wang Deliang Chen 《水文研究》2021,35(9):e14327
Tonle Sap Lake (TSL) is one of the world's most productive lacustrine ecosystems, driven by the Mekong River's seasonal flood pulse. This flood pulse and its long-term dynamics under the Mekong River basin's (MRB) fast socio-economic development and climate change need to be identified and understood. However, existing studies fall short of sufficient time coverage or concentrate only on changes in water level (WL) that is only one of the critical flood pulse parameters influencing the flood pulse ecosystem productivity. Considering the rapidly changing hydroclimatic conditions in the Mekong basin, it is crucial to systematically analyse the changes in multiple key flood pulse parameters. Here, we aim to do that by using observed WL data for 1960–2019 accompanied with several parameters derived from a Digital Bathymetry Model. Results show significant declines of WL and inundation area from the late 1990s in the dry season and for the whole year, on top of increased subdecadal variability. Decreasing (increasing) probabilities of high (low) inundation area for 2000–2019 have been found, in comparison to the return period of inundation area for 1986–2000 (1960–1986). The mean seasonal cycle of daily WL in dry (wet) season for 2000–2019, compared to that for 1986–2000, has shifted by 10 (5) days. Significant correlations and coherence changes between the WL and large-scale circulations (i.e., El Niño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO) and Indian Ocean Dipole (IOD)), indicate that the atmospheric circulations could have influenced the flood pulse in different time scales. Also, the changes in discharge at the Mekong mainstream suggest that anthropogenic drivers may have impacted the high water levels in the lake. Overall, our results indicate a declining flood pulse since the late 1990s. 相似文献
5.
《水文科学杂志》2013,58(1):98-99
Abstract Lake Poopó, within the large Altiplano basin of Bolivia, is connected upstream to Lake Titicaca and downstream to the salares, the big salt fields. Small changes in precipitation and river inflows strongly affect the extent of the lake surface area. For times when there are no satellite images, it is difficult to determine the extent of the lake from observations. Water balance computations were performed to create a water-level series for Lake Poopó extending back in time. The dominant water inflow to Lake Poopó is from the River Desaguadero, which constitutes the outflow of Lake Titicaca. The water-balance computations confirm the crude peasant knowledge about historical lake status. It is found that if the lake level is less than 1 m during the wet season, there is a risk that this shallow lake dries out in the dry season. 相似文献
6.
Humid Little Ice Age in arid central Asia documented by Bosten Lake, Xinjiang, China 总被引：15，自引：0，他引：15
J. A. Holmes 《中国科学D辑(英文版)》2006,49(12):1280-1290
Short sediment cores retrieved from Bosten Lake, the largest inland freshwater lake in China, were used to explore humidity and precipitation variations in arid central Asia during the past millennium. The chronology of the cores was established using 137Cs, 210Pb and AMS 14C dating re- sults. Multi-proxy high-resolution analysis, including pollen ratios of Artemisia and Chenopodiaceae (A/C), carbonate content and grain size, indicates that the climate during the past millennium can be divided into three stages: a dry climate between 1000―1500 AD, a humid climate during the Little Ice Age (LIA) (c. 1500―1900 AD), and a warm dry period after 1900 AD. On centennial timescales, the climate change in northwestern China during the past 1000 years is characterized by oscillations between warm-dry and cold-humid climate conditions. All the proxies changed significantly and indi- cate increased precipitation during the LIA, including increased pollen A/C ratios and pollen concen- trations, decreased carbonate content and increased grain size. The humid period during the LIA re- corded by the Bosten Lake sediments is representative of arid central Asia and is supported by nu- merous records from other sites. During the LIA, the water runoff into the Keriya River and Tarim River in the Tarim Basin increased, while the ice accumulation in the Guliya ice core increased. Additionally, the lake levels of the Aral and Caspian Sea also rose, while tree-ring analysis indicates that precipita- tion increased. We hypothesize that both the lower temperature within China and the negative anomalies of North Atlantic Oscillation (NAO) during this period may have contributed to the humid climate within this area during LIA. 相似文献
7.
洞庭湖水面面积与城陵矶水位之间的绳套关系 总被引：1，自引：0，他引：1
洞庭湖是我国第二大淡水湖,与长江连通,在防洪抗旱和湿地生态保护等方面具有重要的现实意义.采用Terra/MODIS L1B遥感数据,提取了2000-2012年洞庭湖水面面积,结合同期城陵矶水位观测数据,建立了城陵矶水位与洞庭湖水面面积的绳套关系曲线.分析结果表明:2000-2012年间,洞庭湖水面面积呈现总体减少的趋势;在季节上表现为规律性的涨落,具有明显的涨(4-6月)-丰(7-9月)-退(10-12月)-枯(1-3月)的水文特征;在空间格局上表现为由湖体中心向外扩张,随后由外向湖体中心逐渐收缩的变化过程;洞庭湖水面面积与城陵矶水位之间具有较高的相关性,但不同时期的相关系数存在一定的差异:枯水期二者相关性较低,丰水期相关性最高,涨水期和退水期相关性较高;这种差异与各个时期的主导因素不同有关,长江来水对枯水期、丰水期的绳套关系影响较大,其中东洞庭湖最为明显;不论丰水年(2002年)或干旱年(2011年),洞庭湖水面面积变化与城陵矶水位之间的相关性均较高.研究结果对于深入认识江湖关系的宏观复杂性、长江中下游地区以及洞庭湖水域洪涝灾害的预防和治理都具有积极的意义. 相似文献
8.
鄱阳湖鱼类资源及渔业利用 总被引：13，自引：3，他引：10
1997年冬至2000年春,对我国最大淡水湖鄱阳湖的鱼类与渔业利用状况进行了调查.在1955年至2000年期间,鄱阳湖累计记录鱼类136种,隶属于25科78属;其中鲤科鱼类最多,有71种,占总种数的52.2%,其次是鲿科,12种,占8.8%本次调查期间共记录鱼类101种,新记录鱼类6种,即亮银鮈、洞庭小鳔鮈、光唇蛇鮈、短须鱊、方氏鳑鲏和粘皮鲻鰕虎鱼.还分析了该湖鱼类区系组成的变化、主要渔具的渔获物组成特征以及渔产量动态,提出了未来湖泊渔业可持续发展的建议. 相似文献
9.
全新世以来洞庭湖的演变 总被引：25，自引：1，他引：24
本文根据全新世沉积物的岩性、岩相特征和文化遗址的时空分布,结合孢粉资料与历史文献记载,揭示了全新世以来洞庭湖演变的六个阶段:(1)晚更新世末至全新世初为河湖切割平原;(2)中全新世早、中期(8000—5000a B.P.)是湖泊扩展时期;(3)中全新世晚期(5000—3000 a B.P.)四水复合三角洲发育,湖沼洼地零星分布;(4)商周至秦汉(3000—1700 a B.P.)四水分流间洼地湖泊和沼泽广布,汛期河湖水体相连;(5)魏晋至19世纪中叶,洞庭湖逐渐发展至鼎盛阶段;(6)19世纪中叶至今,三角洲迅速推进,湖泊逐渐萎缩。研究认为这种发育演化过程与区域性气候变化、人类活动直接相关。 相似文献
10.
大型通江湖泊洞庭湖的鱼类物种多样性及其时空变化 总被引：12，自引：3，他引：9
为了解通江湖泊鱼类物种多样性现状,于2004年3月-2004年12月和2005年5月对洞庭湖城陵矶、岳阳和沅江三个区域的鱼类进行逐月调查.共鉴定鱼类69种,隶属6目14科44属,其中59.4%为鲤科鱼类.以种类数和多样性指数分析了群落多样性特征,结果表明洞庭湖鱼类种类多样性较高,且时空变化较大.一般地,湖区与长江干流的距离越近,种类数达到峰值的时间就越早;鱼类多样性在春夏季高于秋冬季,在南洞庭湖高于其它两个区域.以优势度>5000为标准,全湖有17种优势种,其中80.0%为湖泊定居性鱼类.在生态类群方面,湖泊定居性鱼类种类最多,占总种类数的74.0%;江湖洄游性鱼类最少,占13.0%.对比分析显示,由于生境丧失、天然苗种资源衰退和过度捕捞等原因,洞庭湖鱼类多样性较20世纪70年代明显下降,洄游鱼类种类数减少;通江湖泊鱼类多样性明显高于阻隔湖泊,表明江湖阻隔造成鱼类多样性下降,因此,加强江湖连通是保护鱼类多样性的有效手段. 相似文献
11.
12.
太湖鱼类区系变化和渔获物分析 总被引：10，自引：4，他引：6
20世纪80年代之前,太湖有鱼类107种、25科,属4个生态类型:洄游型、江湖洄游型、河流型和湖沼型.自2002年9月至2006年1月进行了太湖鱼类采集,共采得鱼类60种、18科.其中,除放流的鱼类外,都能在封闭的湖泊环境中完成生命周期(湖沼生态型);团头鲂、鲮、银鲫和尼罗罗非鱼属移植种类.团头鲂、鳙、鲢、草鱼和青鱼是从20世纪60年代起每年向湖中放流的鱼类;鳗鲡则是自1976年起放流从长江采捕的鳗苗.20世纪50年末至1985年,长江和太湖之间人为隔断,不能在静水中繁殖的鱼类在湖中消失,自然鱼类资源下降;加上过度捕捞和对繁殖群体缺少保护,导致鱼类群体小型化.最后,对太湖渔业资源的优化进行了讨论,并进一步提出对策. 相似文献
13.
内陆水域二氧化碳(CO2)排放是全球碳平衡的重要组成部分,全球CO2排放通量估算通常有很大不确定性,一方面源于CO2排放数据观测的时空离散性,另一方面也是缺少水文情景与CO2排放通量关联性的研究.本文观测了2018年洪泽湖不同水文情景表层水体CO2排放通量特征,并探讨其影响因素.结果表明,洪泽湖CO2排放通量为丰水期((106.9±73.4) mmol/(m2·d))>枯水期((18.7±13.6) mmol/(m2·d))>平水期((5.2±15.5) mmol/(m2·d)),且碳通量由丰(310.2~32.0 mmol/(m2·d))、枯(50.8~2.2 mmol/(m2·d))、平(-17.3~39.8 mmol/(m2·d))3种水文情景的交替表现出湖泊碳源到弱碳汇的转变,空间上CO2排放通量总体呈现北部成子湖区低、南部过水湖区高的分布趋势.洪泽湖CO2排放对水文情景响应敏感,特别是上游淮河流域来水量的改变,是主导该湖CO2排放时空分异的重要因子.丰水期湖泊接纳了淮河更多有机和无机碳的输入,外源碳基质的降解和矿化显著促进了水体CO2的生产与排放,同时氮、磷等营养物质的大量输入,加剧了水体营养化程度,进一步提高CO2排放量,间接反映出人类活动对洪泽湖CO2变化的深刻影响.平、枯水期随着上游淮河来水量的减少,驱动水体CO2排放的因素逐渐由外源输入转变为水体有机质的呼吸降解.此外,上游河口区DOM中陆源类腐殖质的累积与矿化能够促进CO2的排放,而内源有机质组分似乎并没有直接参与CO2的排放过程.研究结果揭示了水文情景交替对湖库CO2排放的重要影响,同时有必要进行高频观测以进一步明晰湖泊的碳通量变化及其控制因素. 相似文献
14.
枝角类作为淡水湖泊生态系统中的初级消费者之一,对生存环境的改变极为敏感.本文分析了太湖西、中和东部等湖区的钻孔沉积物、表层沉积物以及春夏秋季活体枝角类的组成与丰度.结果表明:活体枝角类组成以象鼻溞(Bosmina spp.)为优势种,秋季枝角类属种数量最多.太湖不同生态型湖区表层沉积物枝角类组成均以象鼻溞为优势种,其中西部与中心湖区的枝角类组成与丰度较为相似,种类单一,枝角类绝对丰度高;东部湖区枝角类属种较为丰富,绝对丰度低,优势种由浮游种象鼻溞以及沿岸种圆形盘肠溞(Chydorus sphaericus sl)和西方笔纹溞(Graptoleberis testudinaria)等种属构成.百年以来,太湖枝角类组成与丰度随着营养水平增加而改变,富营养指示种(Bosmina longirostris)丰度的增加与贫营养指示种(Bosmina longispina)丰度的下降,响应了湖区生态环境的演变过程.1970s末期,太湖西部与中心湖区在进入富营养化阶段,枝角类组成单一,象鼻溞占有绝对优势,与东部湖区相比,沿岸种、底栖种稀少.东部湖区在1960s以后,枝角类属种数量增加,但丰度下降,响应了1960s以来该区域营养水平提高、沉水植被生物量增加以及沼泽化加剧的环境过程. 相似文献
15.
The chloride concentration in Lake Constance, by volume the second largest lake in Europe, has increased by a factor of 2.4
during the past 40 years. Based on a chloride budget for the year 2006, we estimated total chloride imports to the catchment
at 101 kt year−1. Road deicing salts contributed 52%, waste water 23%, farming 11%, soil weathering 9%, precipitation and solid waste incineration
3% to this import. River monitoring programs in Switzerland, Germany, and Austria in 2006 traced an average total chloride
export from the catchment into Lake Constance of almost 70 kt and an export from the lake of 56 kt. About one-third of this
load to the lake originated from the Alpine Rhine catchment (Switzerland), and about 60% from various smaller tributaries
in Austria and Germany. The average annual import of chloride to Lake Constance for the years 1995–2007 was 60 kt, the export
almost 57 kt. This budget is in good agreement with the observed increase in the chloride content of the lake and thus confirms
the appropriateness and quality of the long-term monitoring program conducted by Swiss, German and Austrian laboratories.
For the year 2006, we estimated that about 65% of the chloride spread onto roads for deicing and manure on cultivated land
reached the lake within the year of their application. The missing 35% remained transiently in the soil and groundwater of
the catchment. 相似文献
16.
太湖富营养化现状及原因分析 总被引：110，自引：24，他引：86
根据2005-2006年太湖湖泊生态系统研究站的监测结果,结合历史监测记录,评价了近5年来太湖富营养化的趋势.结果显示,从2000年以来,太湖的富营养化状况有加重趋势.主要表现在:1)与历史监测资料对比,近5年来无论梅梁湾还是湖心区,夏季水体TN、TP含量均呈增高趋势,如1992-2001年,太湖湖心区夏季(6-8月份)水体TN的平均值为1.706 mg/L (范围1.238-2.266mg/L),而2002-2006这5年间该平均值为2.344mg/L(范围1.924-2.717mg/L),明显高于前10年(p=0.005),另外,同期湖心区夏季的水体透明度则明显下降(1992—2001年夏季平均值为0.63 m,而2002-2006年则为0.34 m,p=0.003); 2)从野外调查看,太湖夏季水华暴发的范围越来越大,从2000年以前的梅梁湾、竺山湾及部分湖西区为主,发展到2006年的整个西太湖,夏季暴发水华的面积占太湖总面积的一半以上,且一年中出现水华的时间越来越长,水华出现的频率越来越高,微囊藻水华为特征的藻型生态系统在大太湖似乎越来越稳定;3)近年来太湖沉水植物分布区的面积有所下降.研究表明,太湖近年来富营养化的现状不容乐观,原因可能与近几年异常的气候和水文条件有关,也可能与水草区的不断破坏而减弱了微囊藻水华的生态竞争有关,应引起有关部门重视. 相似文献
17.
从沉积物特征谈太湖的演变 总被引：8，自引：5，他引：3
通过太湖湖底淤泥层中的微体古生物及其物理化学分析,在西太潮W1孔发现多门类海相化石。海相化石出现的时间约在1100—5000aB.P.之间。据此提出西太湖在全新世期间曾遭受海侵,因而支持了太湖形成于泻湖的说法,同时,还提出海水进入太湖的时间,比以往学者推测的早2000多年。 相似文献
18.
鄱阳湖水龄季节性变化特征 总被引：3，自引：1，他引：2
基于环境水动力学模型EFDC源程序,建立了染色剂模型和水龄模型,在将模型与航测水文数据验证吻合的基础上,分别计算了鄱阳湖自然条件下春、夏、秋、冬季的水龄和倒灌前后鄱阳湖染色剂和水龄分布的变化,以及五河水系各分支河流水龄.分季节的水龄计算表明鄱阳湖水体交换受季节性来水影响明显.夏、秋季的水龄相对较小,在多数年份又受到长江水倒灌的影响导致水龄有所增大;冬、春季水龄较大,亦无长江水倒灌现象,相较于夏、秋季,水域面积明显减少.分支流的水龄计算表明,西南湖区的水体交换主要受到赣江的影响,西北湖区水体交换主要受到修水和赣江的影响,南部湖区主要受到抚河与信江的影响,东部湖区主要受到饶河的影响,湖心区和入江水道则受到五河水系的综合影响.同时水龄的研究表明拟建的鄱阳湖水利枢纽工程"调枯不调洪"的原则是合理的,为鄱阳湖水利枢纽工程论证提供了重要的参考依据. 相似文献
19.
选择1979-2016年间多时期、多类型、多光谱遥感数据,分析评价洞庭湖区内湖近40年的面积变化.结果表明,最近40年洞庭湖区内湖面积保持相对稳定,丰水期间呈上升趋势,枯水期间波动下降,2016年内湖总面积比1980s初减少3.94%.随着湖泊面积增加,湖泊水面面积变化的比例和幅度逐渐减小,大型湖泊（>10 km2）和中型湖泊（5~10 km2）面积相对稳定,小型内湖（<5 km2）面积变化尤为剧烈.内湖水面面积主要受降雨、蒸发等气候因素和生产生活取水、防洪排涝和退田还湖等人为活动调控.1980-2000年和2001-2015年两个时期,洞庭湖区多年平均降雨量呈现不同程度的下降趋势,多年平均蒸发量明显上升.三峡工程运行后,三口分流衰减,但水资源需求量不断增长,退田还湖和留蓄雨洪作为水资源使得丰水期间内湖水面面积增长,气候变化和水资源开发利用导致枯水期水面面积趋于减少.有必要加强洞庭湖区内湖的研究和保护,适当退田还湖提高湖泊率,优化三口水系格局,实施河湖水系连通工程,缓解洞庭湖区季节性水资源紧张问题. 相似文献
20.
近30年洞庭湖季节性水情变化及其对江湖水量交换变化的响应 总被引：1，自引：1，他引：0
江湖水量交换的变化影响着通江湖泊洞庭湖的水情,进而影响湖区社会经济及生态的可持续发展.以洞庭湖城陵矶站、南咀站以及长江干流宜昌站、螺山站1981-2012年逐日水位、流量观测数据为基础,采用单位根检验、方差分析和水位-流量绳套曲线等方法对洞庭湖季节性水情变化特征进行提取,并探究江湖水量交换变化对其产生的影响.研究表明:近30年来洞庭湖水情呈阶段性特征,与相对稳定的1981-2002年相比,2003-2012年湖泊水位总体呈下降趋势,年均水位下降0.43 m;枯、涨、丰、退水期各季水情变化特征为:2003年以后洞庭湖丰水期水位平均下降0.60 m,呈现出"高水不高"现象;退水期水位平均下降1.49 m,退水加快;枯水期水位略有上升,平均上升0.18 m;涨水期水位变化不明显.湖泊退水期水位降幅最为明显,尤其是10月大幅下降,平均下降2.03 m,有提前进入枯水期的趋势.水情变化与江湖水量交换变化密切相关:丰水期,三口(松滋、太平和藕池)分流量减小在一定程度上降低湖泊水位;退水期,三口分流量减小叠加城陵矶出口长江水位下降对洞庭湖产生拉空作用,湖泊出流加快水位被拉低;枯水期,主要是1 3月,城陵矶出口长江水位上升对湖泊顶托作用增强,湖泊出流减缓水位略有抬升. 相似文献