基于实测光谱与MODIS数据的太湖悬浮物定量估测

以太湖为研究区域,对太湖水体的水面反射光谱进行实地测试,并取样在实验室进行水质分析;根据光谱分析得到的悬浮物特征波段,估测悬浮物浓度;最后,对比MODIS波段,用最敏感波段及主成分分析法建立悬浮物估测模型.结果表明,576nm附近的反射率峰值、841nm处反射率一阶微分值和808nm附近的反射峰高与悬浮物浓度都有较好的相关性,其中峰高法和一阶微分法对悬浮物浓度的估测精度相当;MODIS波段1与悬浮物浓度相关性最好,经过主成分变化后的第一主成分和第二主成分可以较好地估测悬浮物浓度.因此,可利用MODIS数据对太湖悬浮物进行长期动态监测.

Suspended solids concentration estimation in Lake Taihu using field spectra and MODIS data

Taking Lake Taihu as the study area, the field reflectance spectrum was measured, and the in-situ water samples were collected and analyzed in the lab. After analyzed the spectrum features, suspended solids (SS) concentration were estimated by field spectra. Then by the comparison of the bands of MODIS and the correlation between SS and MODIS bands reflectivity, the principal component analysis (PCA) were analyzed. The most practicable band, the first and the second principal component were selected to educe the estimation models. The results show that the peak value near 576nm, the peak height near 808nm, and the first derivative at 841nm have good correlations with SS concentration. Among these, the estimation precisions of the two later are close. The correlation between MODIS band 1 and SS concentration is more corresponding than the other bands. The precisions to estimate SS using the first and the second principal component are also good. Therefore, MODIS data can be used in long term dynamic monitoring of SS concentration in Lake Taihu.