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利用环境小卫星CCD(HJ CCD)影像对杭州湾悬浮泥沙浓度(SSC)进行了反演研究。通过对杭州湾水体遥感反射率(Rrs)与SSC进行相关性分析发现,在690nm和830nm左右出现显著的反射峰,分别位于HJ CCD影像的第3和第4波段范围内;大于700nm波长处的Rrs与SSC相关性较好。基于实测Rrs和SSC之间的相关关系,利用第4和第3波段比值作为遥感因子建立SSC反演模型,模型决定系数达到0.90。借鉴近红外-短波红外(NIR-SWIR)结合的大气校正方法反演出的准同步MODIS气溶胶数据,实现了HJ CCD影像的大气校正,第3、第4波段的大气校正结果相对误差分别为5.54%和6.97%。结果显示,HJ CCD影像反演的SSC相对误差为7.12%;杭州湾悬浮泥沙浓度要显著高于长江口,且内部差异明显。研究表明,通过适当的大气校正方法和反演算法,HJ CCD影像可用于杭州湾悬浮泥沙浓度的估计。
Suspended sediment concentration (SSC) in the Hangzhou Bay was retrieved by using HJ CCD images. Correlation analysis between remote sensing reflectance (Rrs) and SSC in Hangzhou Bay showed that significant reflection peaks appeared at 690 nm and 830 nm, respectively, which were located in the third and fourth bands of HJ CCD images respectively. Rrs and SSC correlation is good. Based on the correlation between measured Rrs and SSC, the SSC inversion model was established by using the ratio of the 4th and 3rd bands as the remote sensing factor, and the model determination coefficient reached 0.90. Based on the NIR-SWIR combined atmospheric correction method, the quasi-synchronous MODIS aerosol data were used to realize the atmospheric correction of HJ CCD images. The relative errors of the atmospheric correction results of the 3rd and 4th bands were 5.54 % And 6.97%. The results showed that the relative error of SSC of HJ CCD image retrieval was 7.12%. The suspended sediment concentration of Hangzhou Bay was significantly higher than that of the Yangtze River estuary, and the internal difference was obvious. The results show that the HJ CCD image can be used to estimate the concentration of suspended sediment in Hangzhou Bay through proper atmospheric correction and inversion algorithms.