海岸带和内陆水体透明度动态变化特征及其主导影响因素

Dynamic Change Characteristics and Its Dominant Influencing Factors of Secchi Disk Depth in Coastal and Inland Waters

基于太湖、鄱阳湖、珠江口和大亚湾水域大量的生物-光学数据,提出透明度高度(SD_H)法评价水域的透明度,并将该方法应用于新一代水色卫星传感器Suomi NPP VIIRS,揭示了水体透明度的动态变化特征。分析了不同水域透明度的主导影响因素,对比了珠江口水域VIIRS和中分辨率成像光谱仪(MODIS)的透明度产品,并讨论了两者的水环境监测能力。结果表明,基于VIIRS的488,555,672nm波段构建的SD_H模型适用于研究水域,可以解释79%的透明度变化。将所提模型应用于预处理后的VIIRS卫星遥感影像,可得到太湖、鄱阳湖、珠江口和大亚湾水体透明度的空间分布特征。相对于浮游植物,悬浮物和有色溶解有机物是影响海岸带和内陆水体透明度的主导因子。VIIRS和MODIS的透明度产品在空间上保持一致,但VIIRS透明度产品的空间分辨率优于MODIS,环境监测能力较强。

Based on mass bio-optical data from Taihu Lake, Poyang Lake, Pearl River Estuary and Daya Bay, we propose a method called Secchi disk depth （SD_H） to evaluate the water transparency. The method is applied to the new generation water color satellite sensor Suomi NPP VIIRS. The dynamic change characteristics of water transparency are revealed. We analyze the dominant influencing factors of transparency in different waters, compare the transparency products of VIIRS and moderate-resolution imaging spectroradiometer （MODIS） in Pearl River Estuary, and discuss their water environmental monitoring capacity. The results show that the SD_H model constructed based on VIIRS at 488, 555, 672 nm is suitable for water investigation, which can explain 79% of the transparency variation. We apply the proposed model to VIIRS satellite remote sensing images after pretreatment, and get the spatial distribution characteristics of water transparency in Taihu Lake, Poyang Lake, Pearl River Estuary and Daya Bay. Compared to phytoplankton, the suspended sediments and chromophoric dissolved organic matter are the dominant factors influencing the Secchi disk depth in coastal and inland waters. Transparency products of VIIRS and MODIS are consistent in space. However, the transparency product of VIIRS has a better spatial resolution and a stronger environmental monitoring ability.