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Estimating CDOM Concentration in Highly Turbid Estuarine Coastal Waters
Author(s) -
Zhao Jun,
Cao Wenxi,
Xu Zhantang,
Ai Bin,
Yang Yuezhong,
Jin Guangzhen,
Wang Guifen,
Zhou Wen,
Chen Yong,
Chen Haiyun,
Sun Zhaohua
Publication year - 2018
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2018jc013756
Subject(s) - colored dissolved organic matter , estuary , plume , environmental science , mean squared error , support vector machine , pearl , remote sensing , oceanography , meteorology , geology , mathematics , computer science , chemistry , statistics , geography , machine learning , organic chemistry , phytoplankton , archaeology , nutrient
We proposed a support vector machine (SVM) algorithm to retrieve colored dissolved organic matter (CDOM) concentration (using a g (443) as a proxy) in the highly turbid Pearl River estuary. Two band ratios, namely, R rs (443)/R rs (547) and R rs (488)/R rs (547), were used as inputs. Comparisons between the estimated and measured a g (443) illustrated high accuracy of the SVM algorithm, yielding R 2 s of 0.98 and 0.89, mean absolute percentage errors of 5.18% and 13.1%, and root‐mean‐square deviations of 0.012 and 0.034 m −1 for the training and validation data sets, respectively. The SVM algorithm was also evaluated against existing ones for the study area and gave the best accuracy with a R 2 of 0.9, a mean absolute percentage error of 10.23%, and a root‐mean‐square deviation of 0.025 m −1 . The diurnal dynamics of CDOM in the Pearl River estuary was revealed showing complicated variations and influenced by the combined effects of wind, tide, circulation, and river discharge. As for remote sensing applications, the SVM‐based CDOM product exhibited great potential to trace the Pearl River plume and the satellite‐derived plume area agreed well with the FVCOM model simulation result. SVM is an accurate and fast tool for retrieving CDOM concentration, especially in highly turbid estuarine coastal waters, and thus, river plume dynamics can be traced.