高矿化度沙漠湖泊水体的光学特性

Water optical properties of high mineralization in desert lakes

沙漠湖泊水体和东部大型湖泊如太湖等存在较大差异.为深入研究沙漠湖泊水体的光学特性,利用腾格里沙漠月亮湖实测水面ASD高光谱数据和同步采集的水样,对水体矿化度与叶绿素a、DOC、悬浮物的含量进行相关性分析,比较沙漠湖泊水体和其它水体的黄色物质、浮游植物、非藻类悬浮物吸收特征光谱,探讨不同波段中水深和矿化度对水体反射率的影响.结果表明水体矿化度和水深分别是影响沙漠湖泊水体固有光学特性和表观光学特征的最主要因素:矿化度显著影响所有物质的吸收特性,与DOC含量和240-300nm段内的黄色物质吸收系数具有很好的相关性;水深显著影响水体的遥感反射率,但在550-700nm波段同一水深范围内矿化度成为影响水体反射率的主要因素.本研究为今后利用遥感数据监测沙漠湖泊矿化度等水质指标提供了理论基础.

Lakes in desert areas are very different from large lakes in the eastern part of China,like Lake Taihu.The objective of this study was to find out the optical properties of desert lakes.Reflectance spectra were measured in October 2009 with ASD FieldSpec spectrometer.Concurrently,water samples were collected directly from the lake to be analyzed in laboratory.After correlation analysis between the TDS and concentration of chlorophyll-a,DOC,TSM,comparing absorption spectra of NPSS,CDOM,chlorophyll-a,and discussion of the remote sensing reflectance in different wave bands,the result shows TDS and water depth are the main influence of IOPs and AOPs.The TDS has influenced the absorption properties remarkably and has high correlation coefficient with the concentration of DOC and with absorption of CDOM in 240-300nm.Water depth is most important factor of remote sensing reflectance,and TDS plays a major role in 550-720nm within the same water depth ranges.These conclusions may provide useful RS basis to estimate water quality parameters in desert lakes.