高浑浊河流悬沙质量浓度的地面遥感监测方法  

Estimation of suspended sediment concentration in rivers with In-situ remote sensing techniques: an example from the lower Jinsha tributary

作　　者：周跃[1] 吕喜玺[2] 陈平[2] S.Liaw 朱云梅[1] 

机构地区：[1]昆明理工大学环境科学与工程学院,云南昆明650093 [2]新加坡国立大学

出　　处：《生态环境》2005年第5期706-709,共4页Ecology and Environmnet

基　　金：国家973项目专题(2003CB415105-6);云南省人才基金项目(1999D0027G);云南省自然科学基金项目(2002D0017M)

摘　　要：以金沙江中下游一级支流龙川江为例,通过探讨河流地面反射光谱与河流悬沙质量浓度的关系,初步开发了河流悬沙质量浓度的地面遥感预测技术。研究发现,基于R800/R550的经验模型,仅能够预测浓度范围在400 g.m-3以下的悬沙质量浓度值,对于较低悬沙质量浓度的河流或其他水域有较大运用价值。光学拟合技术能够预测龙川江在其整个变化范围的河流悬沙质量浓度,最高预测浓度可以达到13 000 g.m-3。通过直接运用两种方法,或者进一步将它们提升成为卫星遥感运用技术后,对于中国西南众多的江河湖库有着重要的理论和现实意义。we developed algorithms for estimating suspended sediment concentrations （SSC） in highly turbid inland river waters from remote sensing reflectance measurements in the visible and near-infrared wavelength bands. The algorithms were calibrated using ground measurements of SSC and water reflectance spectra at Longchuangjiang Tributarie of the Upstream of Yangzts River. A GER 1 500 handheld spectrometer was used to acquire the reflectance spectra. Suspended sediment concentrations were measured using the standard method of water filtration. The SSC values spanned a wide range from 16 g.m^-3 to 13 000 g.m^-3. The median and average concentrations were about 800 and 1 900 g.m^-3 respectively. The ratio of the reflectance at 800 nm and 550 nm （R800/R550） was to correlate well with SSC up to approximately 250 g.m^-3. The ratio R800/R550 could be fitted to a equation. This equation could be inverted to obtain the SSC value from the measured reflectance in the green and the near-infrared bands. This inversion algorithm could not be used for waters with very high SSC, as the ratio R800/R550 remained approximately constant at high SSC. More than half of our sampling points fell into this category. In this case, we fitted the water reflectance spectra to an optical model of water reflectance with the backscattering coefficient of sediment particles at 550 nm （X550） and the absorption coefficient of dissolved organic matter at 440 nm （G440） as the fitting parameters. The suspended sediment backscattering coefficient X550 was found to vary linearly with SSC for the whole range of measured SSC values （up to 13 000 g.m^-3）, with a high correlation coefficient （R-squared） of 0.97. In the second inversion algorithm, X550 was first retrieved from a reflectance spectrum using the spectral fitting method. The SSC value was then calculated using the relation between SSC and X550. The first algorithm used only the reflectance at two bands and hence would be suitable for use in estimating SSC from LANDSAT or SPOT

关 键 词：悬沙质量浓度 地面遥感 光谱特征 

分 类 号：X87[环境科学与工程—环境工程]