为探究洞里萨湖流域土地利用变化对湖泊水质的影响,以MODIS土地覆盖产品(MCD12Q1)、湖泊浊度和营养状态指数为数据源,结合地理信息系统(geographic information system,GIS)空间分析、Theil-Sen Median趋势分析、Mann-Kendall检验和相...为探究洞里萨湖流域土地利用变化对湖泊水质的影响,以MODIS土地覆盖产品(MCD12Q1)、湖泊浊度和营养状态指数为数据源,结合地理信息系统(geographic information system,GIS)空间分析、Theil-Sen Median趋势分析、Mann-Kendall检验和相关性分析等方法,系统研究该流域近20年土地利用与湖泊水质的时空变化特征及两者间的关联性。结果表明:洞里萨湖流域土地利用以林地显著减少(P<0.01)和草地、耕地显著增加(P<0.01)为主要特征,年均变化率分别达到了流域总面积的-1.13%、0.8%和0.35%;相应地,湖泊浊度和营养状态指数亦为上升趋势,但未通过显著性检验。研究时段内,湖泊浊度与林地强负相关(r=-0.65),与草地、耕地和建设用地强正相关,相关系数分别为0.61、0.74、0.72,与湿地弱正相关(r=0.35);然而,湖泊营养状态指数仅与湿地弱负相关(r=-0.31)。研究结论为认识洞里萨湖水质变化的驱动因子与流域管理提供科学参考。展开更多
Lake is an important part of the natural ecosystem, and its morphological characteristics reflect the capacity of lake regulation and storage, the strength of material migration, and the characteristics of shoreline d...Lake is an important part of the natural ecosystem, and its morphological characteristics reflect the capacity of lake regulation and storage, the strength of material migration, and the characteristics of shoreline development. In most existing studies, remote sensing images are used to quantify the morphological characteristics of lakes. However, the extraction accuracy of lake water is greatly affected by cloud cover and vegetation cover, and the inversion accuracy of lake elevation data is poor, which cannot accurately describe the response relationship of lake landscape morphology with water level change. Therefore, this paper takes Tonle Sap Lake as the research object, which is the largest natural freshwater lake in Southeast Asia. DEM is constructed based on high-resolution measured topographic data, and morphological indicators such as lake area, lake shoreline length, perimeter area ratio, longest axis length, maximum width, shoreline development index, lake shape complexity, compactness ratio and form ratio are adopted to researching the evolution law of high water overflows and low water outbursts quantitatively, and clarifying the variation characteristics of landscape morphology with water level gradient in Tonle Sap Lake. The research results have important theoretical significance for the scientific utilization of Tonle Sap Lake water resources and the protection of the lake ecosystem.展开更多
Tonle Sap sedimentary basin was considered a favorable geological condition for hydrocarbon accumulation in the onshore Cambodia. Two exposure outcrops in Battambang province, called Somlout and Takream, were selected...Tonle Sap sedimentary basin was considered a favorable geological condition for hydrocarbon accumulation in the onshore Cambodia. Two exposure outcrops in Battambang province, called Somlout and Takream, were selected to represent sediments in this basin. The sedimentology and geochemistry studies provide insights into the depositional environment of sediments using field investigation, lithological, sedimentological, paleontological, and geochemical analysis. The redox condition, water column, and depositional setting were analyzed by plotting the ratio of V vs. Cr, Uauthigenic vs. V/Cr, Sr vs. Ba, Ca vs. (Fe + Ca), and Fe<sub>2</sub>O<sub>3</sub>/TiO<sub>2</sub> vs. Al<sub>2</sub>O<sub>3</sub>/(Al<sub>2</sub>O<sub>3</sub> + Fe<sub>2</sub>O<sub>3</sub>) diagram. Moreover, these diagrams can be used to predict depositional conditions as well. Based on the results, Somlout and Takream comprise calcareous shale and limestone facies. The geochemical analysis showed that Somlout calcareous shale samples were deposited in the dysoxic freshwater of the lake setting during the regression, while Somlout limestones and Takream were deposited in high salinity seawater, oxic condition of shallow-marine water. In addition, Somlout limestones consist of fragmental fusulinid foraminifera, bivalve shelve, and bryozoan, which suggest a barrier environment. Meanwhile, Teakream consists of fine-grained calcareous shale, and lime-mudstone, which are presented to form in the quiet marine setting of the lagoon environment. Therefore, the Tonle Sap basin sediments were deposited in the Somlout area’s barrier and lake environment, and the lagoon environment for Takream.展开更多
湖泊表面水温(Lake surface water temperature,LSWT)是一个重要的水生态环境指标,对气候变化和人类活动具有指示作用。本文以洞里萨湖为研究对象,以MODIS地表温度产品数据(MOD11A2)和近湖面2m处的气温数据(Atmospheric temperature,AT...湖泊表面水温(Lake surface water temperature,LSWT)是一个重要的水生态环境指标,对气候变化和人类活动具有指示作用。本文以洞里萨湖为研究对象,以MODIS地表温度产品数据(MOD11A2)和近湖面2m处的气温数据(Atmospheric temperature,AT)为数据源,结合遥感技术、GIS空间分析技术和数理统计分析方法,系统分析了洞里萨湖2001~2018年LSWT和AT的时空变化特征,定量研究了LSWT与AT间的响应关系。研究表明,近20年洞里萨湖LSWT与AT均呈现明显的变暖趋势,AT与LSWT间呈现显著的正相关关系。本研究填补了洞里萨湖长时间系列LSWT的研究空白,为该湖的环境保护和管理提供决策支持。展开更多
洞里萨湖(Tonle Sap Lake)是东南亚最大的淡水湖泊,研究其水体颜色的时空分布能够为评估洞里萨湖水质综合状态的变化提供重要信息.该研究使用2000年-2018年间中分辨率成像光谱仪MODIS的地表反射率数据,在水体颜色指数FUI模型的基础上,...洞里萨湖(Tonle Sap Lake)是东南亚最大的淡水湖泊,研究其水体颜色的时空分布能够为评估洞里萨湖水质综合状态的变化提供重要信息.该研究使用2000年-2018年间中分辨率成像光谱仪MODIS的地表反射率数据,在水体颜色指数FUI模型的基础上,定量分析了洞里萨湖色调角的年际变化和年内差异、色调角与水面面积的关系、水体颜色变化率的空间分布特征、以及富营养化状态的逐年变化.结果表明:1)洞里萨湖的水体颜色在19年间呈现由黄向绿的转变,但不显著,2014年-2016年的年内差异明显减小并出现了短暂的稳定;2)不同月份色调角的逐年变化趋势存在明显差异,有8个月的色调角与面积存在显著的相关关系,最强的正/负相关关系分别出现在雨季6月(R=0.72)和旱季12月(R=-0.86);3)在雨季、旱季的代表月份6月、12月,色调角年际变化率的空间分布差异较大,12月的逐年变化幅度明显高于6月,但变化趋势呈现显著性的区域较少;4)19年间,洞里萨湖的营养化状态在雨季6月以“富营养”状态为主,在旱季12月存在明显差异.研究结果量化了近20年来洞里萨湖水体颜色或水质综合状态、富营养化程度的演变程度及空间分布,为该湖泊的水质监测与治理提供基础数据支持.展开更多
Concern on alteration of sediment natural flow caused by developments of water resources system, has been addressed in many river basins around the world especially in developing and remote regions where sediment data...Concern on alteration of sediment natural flow caused by developments of water resources system, has been addressed in many river basins around the world especially in developing and remote regions where sediment data are poorly gauged or ungauged. Since suspended sediment load (SSL) is predominant, the objectives of this research are to: 1) simulate monthly average SSL (SSLm) of four catchments using artificial neural network (ANN);2) assess the application of the calibrated ANN (Cal-ANN) models in three ungauged catchment representatives (UCR) before using them to predict SSLm of three actual ungauged catchments (AUC) in the Tonle Sap River Basin;and 3) estimate annual SSL (SSLA) of each AUC for the case of with and without dam-reservoirs. The model performance for total load (SSLT) prediction was also investigated because it is important for dam-reservoir management. For model simulation, ANN yielded very satisfactory results with determination coefficient (R2) ranging from 0.81 to 0.94 in calibration stage and 0.63 to 0.87 in validation stage. The Cal-ANN models also performed well in UCRs with R2 ranging from 0.59 to 0.64. From the result of this study, one can estimate SSLm and SSLT of ungauged catchments with an accuracy of 0.61 in term of R2 and 34.06% in term of absolute percentage bias, respectively. SSLA of the AUCs was found between 159,281 and 723,580 t/year. In combination with Brune’s method, the impact of dam-reservoirs could reduce SSLA between 47% and 68%. This result is key information for sustainable development of such infrastructures.展开更多
Tonle Sap Lake is the largest river-connected lake, buffer area and ecological zone of Mekong River, which plays a huge role in dispelling flood peak and compensating water, and the conservation of biological diversit...Tonle Sap Lake is the largest river-connected lake, buffer area and ecological zone of Mekong River, which plays a huge role in dispelling flood peak and compensating water, and the conservation of biological diversity. The river-lake relationship between Mekong River and Tonle Sap Lake is unique and has always been a major focus in the international community. The land terrain and under-water topography were used to analyze the morphological characteristics of Cambodia Mekong Delta and Tonle Sap Lake. Long series of hydrological data of river-lake controlling stations were used to analyze the water level variation characteristics and water volume exchange pattern between Mekong River and Tonle Sap Lake, and the response relationship to river-lake morphological characteristics were also researched. The results show that: Cambodia Mekong Delta and Tonle Sap Lake Area is low-lying and flat with gentle channel gradient and water surface gradient, making the relationship between water level and area (or volume) smooth. The channel storage capacity of Mekong River and Tonle Sap River is not enough compared to the inflow, so vast flooding plain is extremely prone to be inundated, making the flood relationships between the left and right banks become very complicated. Tonle Sap Lake is a seasonal freshwater lake with water flowing in and flowing out, and the timing and intensity of water exchange with Mekong River are closely related to the water flow resistance at the exit section of Tonle Sap Lake and the cross-sectional area of Tonle Sap River, which can be reflected by the river-lake water level difference and the water level of Tonle Sap River. Affected by the river-lake morphological characteristics, the water exchange intensity between Mekong River and Tonle Sap Lake is great. Tonle Sap Lake not only stores 14.4% of flood volume (39.7 billion m3) from the Mekong River every year, but also supplies 29.7% of dry water (69.4 billion m3) to the Mekong River. Influenced by the adjustment of the floodplain, the water level fluctuation of Mekong River and Tonle Sap Lake is slow, and the rising and droop rates of water level are positively correlated with the floodplain storage area. The research results will help to understand the relationship mechanism between Mekong River and Tonle Sap Lake and provide a scientific basis for the comprehensive governance of Cambodia Mekong Delta and Tonle Sap Lake Area.展开更多
柬埔寨洞里萨湖(Tonle Sap Lake)位于湄公河下游盆地的中心地带,是汹涌的湄公河的缩影和“心脏”,也是湄公河三角洲复杂生态水文的重要组成部分。如今,生物多样性极为丰富的洪泛区是170万人口的家园,也是含有鱼类物种最多的地区之一,极...柬埔寨洞里萨湖(Tonle Sap Lake)位于湄公河下游盆地的中心地带,是汹涌的湄公河的缩影和“心脏”,也是湄公河三角洲复杂生态水文的重要组成部分。如今,生物多样性极为丰富的洪泛区是170万人口的家园,也是含有鱼类物种最多的地区之一,极易受水电、灌溉、防洪和供水等大型水利工程设施建设的影响。在森林砍伐、种植作物单一、人口增长、国际投资激增、大规模旅游等各种发展压力下,千百年来的人类聚落、多民族的生活和社会文化习俗均受到威胁。同时,受淤积、污染、野生动物(尤其是鱼类和鸟类)资源的过度开发及农林种植规模扩张的影响,湖泊的生态活力岌岌可危。柬埔寨动荡的历史与大幅度土地割据,对其水利基础设施产生了根本性的影响。揭示了人类通过工程建设和领地扩张强化自身影响的情况下,土壤、植被、地形和水等自然景观要素与人类主宰力之间的内在联系。早先人类聚落和生产性景观的形成得益于多种传统生态知识(traditional ecological knowledge,TEK),特别体现在保留至今的众多水上渔村和湖边高脚屋上。批判性地指出,在过去的2个世纪里,人类大规模地侵占自然环境开展工程建设所形成的景观,在某种程度上破坏了自然系统的稳定性,人与自然和谐共生的关系被打破。只有深刻理解区域景观生态内的复杂关系并致力于其恢复重建,才能实现人类与其他物种和谐共生的愿景。展开更多
文摘为探究洞里萨湖流域土地利用变化对湖泊水质的影响,以MODIS土地覆盖产品(MCD12Q1)、湖泊浊度和营养状态指数为数据源,结合地理信息系统(geographic information system,GIS)空间分析、Theil-Sen Median趋势分析、Mann-Kendall检验和相关性分析等方法,系统研究该流域近20年土地利用与湖泊水质的时空变化特征及两者间的关联性。结果表明:洞里萨湖流域土地利用以林地显著减少(P<0.01)和草地、耕地显著增加(P<0.01)为主要特征,年均变化率分别达到了流域总面积的-1.13%、0.8%和0.35%;相应地,湖泊浊度和营养状态指数亦为上升趋势,但未通过显著性检验。研究时段内,湖泊浊度与林地强负相关(r=-0.65),与草地、耕地和建设用地强正相关,相关系数分别为0.61、0.74、0.72,与湿地弱正相关(r=0.35);然而,湖泊营养状态指数仅与湿地弱负相关(r=-0.31)。研究结论为认识洞里萨湖水质变化的驱动因子与流域管理提供科学参考。
文摘Lake is an important part of the natural ecosystem, and its morphological characteristics reflect the capacity of lake regulation and storage, the strength of material migration, and the characteristics of shoreline development. In most existing studies, remote sensing images are used to quantify the morphological characteristics of lakes. However, the extraction accuracy of lake water is greatly affected by cloud cover and vegetation cover, and the inversion accuracy of lake elevation data is poor, which cannot accurately describe the response relationship of lake landscape morphology with water level change. Therefore, this paper takes Tonle Sap Lake as the research object, which is the largest natural freshwater lake in Southeast Asia. DEM is constructed based on high-resolution measured topographic data, and morphological indicators such as lake area, lake shoreline length, perimeter area ratio, longest axis length, maximum width, shoreline development index, lake shape complexity, compactness ratio and form ratio are adopted to researching the evolution law of high water overflows and low water outbursts quantitatively, and clarifying the variation characteristics of landscape morphology with water level gradient in Tonle Sap Lake. The research results have important theoretical significance for the scientific utilization of Tonle Sap Lake water resources and the protection of the lake ecosystem.
文摘Tonle Sap sedimentary basin was considered a favorable geological condition for hydrocarbon accumulation in the onshore Cambodia. Two exposure outcrops in Battambang province, called Somlout and Takream, were selected to represent sediments in this basin. The sedimentology and geochemistry studies provide insights into the depositional environment of sediments using field investigation, lithological, sedimentological, paleontological, and geochemical analysis. The redox condition, water column, and depositional setting were analyzed by plotting the ratio of V vs. Cr, Uauthigenic vs. V/Cr, Sr vs. Ba, Ca vs. (Fe + Ca), and Fe<sub>2</sub>O<sub>3</sub>/TiO<sub>2</sub> vs. Al<sub>2</sub>O<sub>3</sub>/(Al<sub>2</sub>O<sub>3</sub> + Fe<sub>2</sub>O<sub>3</sub>) diagram. Moreover, these diagrams can be used to predict depositional conditions as well. Based on the results, Somlout and Takream comprise calcareous shale and limestone facies. The geochemical analysis showed that Somlout calcareous shale samples were deposited in the dysoxic freshwater of the lake setting during the regression, while Somlout limestones and Takream were deposited in high salinity seawater, oxic condition of shallow-marine water. In addition, Somlout limestones consist of fragmental fusulinid foraminifera, bivalve shelve, and bryozoan, which suggest a barrier environment. Meanwhile, Teakream consists of fine-grained calcareous shale, and lime-mudstone, which are presented to form in the quiet marine setting of the lagoon environment. Therefore, the Tonle Sap basin sediments were deposited in the Somlout area’s barrier and lake environment, and the lagoon environment for Takream.
文摘湖泊表面水温(Lake surface water temperature,LSWT)是一个重要的水生态环境指标,对气候变化和人类活动具有指示作用。本文以洞里萨湖为研究对象,以MODIS地表温度产品数据(MOD11A2)和近湖面2m处的气温数据(Atmospheric temperature,AT)为数据源,结合遥感技术、GIS空间分析技术和数理统计分析方法,系统分析了洞里萨湖2001~2018年LSWT和AT的时空变化特征,定量研究了LSWT与AT间的响应关系。研究表明,近20年洞里萨湖LSWT与AT均呈现明显的变暖趋势,AT与LSWT间呈现显著的正相关关系。本研究填补了洞里萨湖长时间系列LSWT的研究空白,为该湖的环境保护和管理提供决策支持。
文摘洞里萨湖(Tonle Sap Lake)是东南亚最大的淡水湖泊,研究其水体颜色的时空分布能够为评估洞里萨湖水质综合状态的变化提供重要信息.该研究使用2000年-2018年间中分辨率成像光谱仪MODIS的地表反射率数据,在水体颜色指数FUI模型的基础上,定量分析了洞里萨湖色调角的年际变化和年内差异、色调角与水面面积的关系、水体颜色变化率的空间分布特征、以及富营养化状态的逐年变化.结果表明:1)洞里萨湖的水体颜色在19年间呈现由黄向绿的转变,但不显著,2014年-2016年的年内差异明显减小并出现了短暂的稳定;2)不同月份色调角的逐年变化趋势存在明显差异,有8个月的色调角与面积存在显著的相关关系,最强的正/负相关关系分别出现在雨季6月(R=0.72)和旱季12月(R=-0.86);3)在雨季、旱季的代表月份6月、12月,色调角年际变化率的空间分布差异较大,12月的逐年变化幅度明显高于6月,但变化趋势呈现显著性的区域较少;4)19年间,洞里萨湖的营养化状态在雨季6月以“富营养”状态为主,在旱季12月存在明显差异.研究结果量化了近20年来洞里萨湖水体颜色或水质综合状态、富营养化程度的演变程度及空间分布,为该湖泊的水质监测与治理提供基础数据支持.
文摘Concern on alteration of sediment natural flow caused by developments of water resources system, has been addressed in many river basins around the world especially in developing and remote regions where sediment data are poorly gauged or ungauged. Since suspended sediment load (SSL) is predominant, the objectives of this research are to: 1) simulate monthly average SSL (SSLm) of four catchments using artificial neural network (ANN);2) assess the application of the calibrated ANN (Cal-ANN) models in three ungauged catchment representatives (UCR) before using them to predict SSLm of three actual ungauged catchments (AUC) in the Tonle Sap River Basin;and 3) estimate annual SSL (SSLA) of each AUC for the case of with and without dam-reservoirs. The model performance for total load (SSLT) prediction was also investigated because it is important for dam-reservoir management. For model simulation, ANN yielded very satisfactory results with determination coefficient (R2) ranging from 0.81 to 0.94 in calibration stage and 0.63 to 0.87 in validation stage. The Cal-ANN models also performed well in UCRs with R2 ranging from 0.59 to 0.64. From the result of this study, one can estimate SSLm and SSLT of ungauged catchments with an accuracy of 0.61 in term of R2 and 34.06% in term of absolute percentage bias, respectively. SSLA of the AUCs was found between 159,281 and 723,580 t/year. In combination with Brune’s method, the impact of dam-reservoirs could reduce SSLA between 47% and 68%. This result is key information for sustainable development of such infrastructures.
文摘Tonle Sap Lake is the largest river-connected lake, buffer area and ecological zone of Mekong River, which plays a huge role in dispelling flood peak and compensating water, and the conservation of biological diversity. The river-lake relationship between Mekong River and Tonle Sap Lake is unique and has always been a major focus in the international community. The land terrain and under-water topography were used to analyze the morphological characteristics of Cambodia Mekong Delta and Tonle Sap Lake. Long series of hydrological data of river-lake controlling stations were used to analyze the water level variation characteristics and water volume exchange pattern between Mekong River and Tonle Sap Lake, and the response relationship to river-lake morphological characteristics were also researched. The results show that: Cambodia Mekong Delta and Tonle Sap Lake Area is low-lying and flat with gentle channel gradient and water surface gradient, making the relationship between water level and area (or volume) smooth. The channel storage capacity of Mekong River and Tonle Sap River is not enough compared to the inflow, so vast flooding plain is extremely prone to be inundated, making the flood relationships between the left and right banks become very complicated. Tonle Sap Lake is a seasonal freshwater lake with water flowing in and flowing out, and the timing and intensity of water exchange with Mekong River are closely related to the water flow resistance at the exit section of Tonle Sap Lake and the cross-sectional area of Tonle Sap River, which can be reflected by the river-lake water level difference and the water level of Tonle Sap River. Affected by the river-lake morphological characteristics, the water exchange intensity between Mekong River and Tonle Sap Lake is great. Tonle Sap Lake not only stores 14.4% of flood volume (39.7 billion m3) from the Mekong River every year, but also supplies 29.7% of dry water (69.4 billion m3) to the Mekong River. Influenced by the adjustment of the floodplain, the water level fluctuation of Mekong River and Tonle Sap Lake is slow, and the rising and droop rates of water level are positively correlated with the floodplain storage area. The research results will help to understand the relationship mechanism between Mekong River and Tonle Sap Lake and provide a scientific basis for the comprehensive governance of Cambodia Mekong Delta and Tonle Sap Lake Area.
文摘柬埔寨洞里萨湖(Tonle Sap Lake)位于湄公河下游盆地的中心地带,是汹涌的湄公河的缩影和“心脏”,也是湄公河三角洲复杂生态水文的重要组成部分。如今,生物多样性极为丰富的洪泛区是170万人口的家园,也是含有鱼类物种最多的地区之一,极易受水电、灌溉、防洪和供水等大型水利工程设施建设的影响。在森林砍伐、种植作物单一、人口增长、国际投资激增、大规模旅游等各种发展压力下,千百年来的人类聚落、多民族的生活和社会文化习俗均受到威胁。同时,受淤积、污染、野生动物(尤其是鱼类和鸟类)资源的过度开发及农林种植规模扩张的影响,湖泊的生态活力岌岌可危。柬埔寨动荡的历史与大幅度土地割据,对其水利基础设施产生了根本性的影响。揭示了人类通过工程建设和领地扩张强化自身影响的情况下,土壤、植被、地形和水等自然景观要素与人类主宰力之间的内在联系。早先人类聚落和生产性景观的形成得益于多种传统生态知识(traditional ecological knowledge,TEK),特别体现在保留至今的众多水上渔村和湖边高脚屋上。批判性地指出,在过去的2个世纪里,人类大规模地侵占自然环境开展工程建设所形成的景观,在某种程度上破坏了自然系统的稳定性,人与自然和谐共生的关系被打破。只有深刻理解区域景观生态内的复杂关系并致力于其恢复重建,才能实现人类与其他物种和谐共生的愿景。
