基于高光谱数据和MODIS影像的鄱阳湖悬浮泥沙浓度估算

Estimation on Suspended Sedimentation Concentration of Poyang Lake Using MODIS and Hyperspectral Data

本文旨在寻找悬浮泥沙浓度的MODIS遥感影像估算模型,并利用实测的高光谱数据对其敏感波段和反演模型进行测试和验证。以鄱阳湖为研究区域,利用光谱数据进行分析,为利用遥感影像建模提供依据。进一步利用同步进行的鄱阳湖水质采样分析与MODIS影像中等分辨率各个波段反射率及其组合进行相关分析,寻找反演悬浮泥沙浓度的敏感波段。实验表明,MODIS的第一波段反射率对于悬浮泥沙浓度有很好的匹配(R2=0.91;n=25),进而建立了鄱阳湖地区的悬浮泥沙浓度遥感定量估算模型。利用估算模型和鄱阳湖地区历史MODIS影像,得到了鄱阳湖悬浮泥沙浓度分布图。基于对汛期鄱阳湖悬浮泥沙浓度的连续监测,可对长江倒灌入鄱阳湖现象的形态进行观测。

This study aimed to search for the estimation model for suspended sediment concentration （SSC） using Moderate-resolution Imaging Spectroradiometer （MODIS） of medium-resolution data and using hyperspectal reflectance data to identify the most sensitive hyperspectral band. In this study, the utility of MOIDS data and hyperspectral data for analyzing turbid water was examined in Poyang Lake. The spectral characteristics of water surface with high SSC were determined by hyperspectral measurements during the field survey in seven sample points. The regression analysis using hyperspectral data was the basis of the approach using remote sensing data. A strong linear relationship （R^2= 0. 91; n = 25） was established between band 1 MODIS Terra 250 m reflectance and in situ measurements of SSC acquired from different environments in Poyang Lake Basin. The moderate resolution of MODIS 250 m data and the operating characteristics of the instrument provide data well suited for assessing temporal and spatial patterns of SSC in Poyang Lake. Finally, the historical images were analysed using the calibrated model to map the suspended sediments concentrations. Based on monitoring the sequence of suspended sediment concentration during the flood season, the configuration of the back flows of water from Yangtze River can be observed.