A Weighted Algorithm for Estimating Chlorophyll-a Concentration from Turbid Waters

Accurately estimating phytoplankton Chlorophyll-a(Chla) concentration from remotely sensed data is particularly challenging in turbid, productive waters. In this study, a weighted Chla concentration algorithm (WCA) are constructed to smooth the performance of three-bands semi-analytical algorithm(TSA) and four-bands semi-analytical algorithm(FSA). The performance of WCA, TSA and FSA algorithms are calibrated and validated by three independently datasets collected from Chesapeake Bay, USA, Yellow River Estuary, China, and Taihu Lake, China. Results of this study indicated that: (1) The accuracy and stability of TSA, FSA and WCA in Chesapeake Bay have a superior performance than it in Taihu Lake and Yellow River Estuary; (2) In Taihu Lake and Yellow River Estuary, the TSA and FSA algorithms are not stable for estimating Chla concentration, especially in Taihu Lake, the accuracy and stability of TSA, FSA and WCA algorithms are quite bad; (3) The WCA can greatly improve the accuracy and stability of TSA and FSA algorithms, but it is greatly depended on the performance of TSA and FSA algorithms; and (4) Although the TSA, FSA and WCA algorithms are semi-analytical algorithm, however, the optimal bands, accuracy and stability of these algorithms are very timely and located dependence.