A MODIS-Based Retrieval Model of Suspended Particulate Matter Concentration for the Two Largest Freshwater Lakes in China

Suspended particulate matter concentration (CSPM) is a key parameter describing case-II water quality. Empirical and semi-empirical models are frequently developed and applied for estimating CSPM values from remote sensing images; however, they are usually regionor season-dependent. This study aimed to develop a Moderate Resolution Imaging Spectroradiometer (MODIS)-based retrieval model of CSPM for Poyang and Dongting Lake together. The 89 CSPM measurements in Poyang and Dongting Lake as well as their corresponding MODIS Terra images were used to calibrate CSPM retrieval models, and the calibration results showed that the exponential models of MODIS red band and red minus shortwave infrared (SWIR) band at 1240 nm both explained about 76% of the variation of CSPM of Poyang and Dongting Lake together. When the two models were applied to the validation datasets, the results indicated that the exponential model of red band obtained more stable CSPM estimations with no bias at a significance level of 0.05 in both lakes. The MODIS red-band-based model achieved acceptable results for estimating CSPM in both Poyang and Dongting Lake, and it provided a foundation for obtaining comparable spatiotemporal information of CSPM, which will be helpful for comparing, understanding, managing, and protecting the two aquatic ecosystems.