Quantitative Estimation of Particulate Organic Carbon and Diurnal Variation in Inland Eutrophic Lake

A deep understanding of particulate organic carbon is of great significance for the further research of the carbon cycle of water. After testing the applicability of ocean inversion models of POC in inland lakes, results showed that these ocean models cannot be applied in Lake Taihu and Lake Dongting. So we established a single band inversion model and two kinds of dual-band inversion model to be used in case two water, by the use of a near-infrared band(834 nm) and 563nm with 834 nm respectively. The validation of the models shows that the RMSE of the single band model is 1.12 mg/L, MAPE is 35.8%. The RMSE of two kinds of dual-band semi-analytical inversion models are 1.09 mg/L and 1.11 mg/L respectively, and MAPE are 37.3% and 37.8%. All three kinds of models can be used for estimating the concentration of POC in Lake Taihu and Lake Dongting. In order to use remote sensing to observe the variation of POC concentration, we established a model that can be used on GOCI in the region of Lake Taihu, the MAPE of this model is 35%.Then we estimated the POC concentration distribution of the whole lake using GOCI satellite data. Combining the characteristics of GOCI data with high temporal resolution, we analyzed the POC daily variation, and found that the concentration of POC increased from morning to noon, and declined from noon to evening.