中文摘要：

下行漫衰减系数（Kd）是描述水下光场的重要参数，决定水体真光层深度，影响着浮游藻类初级生产力及其分布特征.基于2008-2013年太湖4次大规模野外试验数据，分析太湖水体漫衰减系数特征及其影响因素，建立适用于多种卫星数据且较高精度的太湖水体490 nm处下行漫衰减系数估算模型.结果表明：无机悬浮物是太湖水体漫衰减系数的主要影响因素；红绿波段比值（674 nm/555 nm）最适合于太湖Kd（490）估算，模型反演精度较高（N=72，R2=0.72，RMSE=0.89 m-1，MAPE=21.58%）；利用实测光谱数据，模拟得到MODIS/EOS、OLCI/Sentinel-3、GOCI/COMS和MSI/Sentinel-2等主要传感器波段的信号，构建适用于多种卫星传感器Kd（490）估算的红绿波段模型，建模精度较高（N=72，R2〉0.7，RMSE〈0.9 m-1，MAPE〈22.0%），且进行了验证（N=37，R2〉0.7，RMSE〈0.9 m-1，MAPE〈22.0%）.

英文摘要：

b The downwelling diffuse attenuation coefficient （Kd） plays a critical role in underwater light field. It determines the euphotic depth, and affects the distribution characteristics of phytoplankton and primary productivity. Based on in situ data collected from 4 cruise surveys in Lake Taihu during 2008-2013, both the variations and driving factors of Kd were analyzed, and an algorithm to estimate downwelling diffuse attenuation coefficient at 490 nm for a variety of satellites＇ data was developed and validated. The results show that：（1） suspended particular inorganic matter is the decisive factor of Kd in Lake Taihu;（2） the algorithm of red-green band ratio is the most suitable for estimating Kd（490） in Lake Taihu （N=72, R2=0.72, RMSE=0.89 m-1, MAPE=21.58%）;（3） with the simulated remote sensing reflectance of the main sensor bands such as MODIS/EOS, OLCI/Sentinel-3, GOCI/COMS and MSI/Sentinel-2, the red-green ratio algorithm to estimate Kd（490） was established for a variety of remote sensing sensors（N=72,R2〉0.7,RMSE〈0.9 m-1,MAPE〈22.0%）, and the validation was good as well（N=37,R2〉0.7,RMSE〈0.9 m-1,MAPE〈22.0%）.