Remote sensing of water turbidity in the Eastern China Seas from Geostationary Ocean Colour Imager

ABSTRACT

Water turbidity plays an important role in marine biogeochemical processes and ecosystem. Remote sensing of water turbidity in the Eastern China Seas is still a challenging task due to its large variations spanning more than three orders from coastal highly turbid waters to offshore clear waters. Thus, this study developed a new blended remote sensing algorithm for accurately estimating water turbidity in the whole Eastern China Seas from Geostationary Ocean Colour Imager (GOCI). The general idea of the new blended algorithm is to combine the band forms with the best abilities for deriving water turbidity in turbid waters and relatively clear waters, respectively. Evaluations based on field data showed a good performance of the new blended algorithm with values of the determination coefficient (R²), root-mean-square error (RMSE), mean absolute error (MAE), and mean relative error (MRE) of 0.884, 47.96 NTU, 29.59 and 48.13%, respectively. The proposed algorithm was applied to the GOCI data of 2015; and large spatiotemporal variations of water turbidity in the Eastern China Seas were observed. High values of water turbidity were observed in winter for both coastal and offshore waters, whereas the lowest values were observed in summer. Sediment resuspension drove by wind and tidal forcing, and sediment transportation related to current might be responsible for spatiotemporal variations of water turbidity, while the detailed study is required for further investigations. Overall, this study provides a technological basis which can be used to understand the variation patterns of water turbidity in the Eastern China Seas from GOCI satellite measurements.

Acknowledgements

We deeply acknowledge anonymous reviewers for their constructive comments towards improving this manuscript. We also thank KOSC for providing GOCI satellite data.

Disclosure statement

No potential conflict of interest was reported by the authors.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This research was funded by the National Key Research and Development Program of China [No. 2016YFC1400901 and 2016YFC1400904]; National Natural Science Foundation of China [No. 41876203, 41506200 and 41576172]; Provincial Natural Science Foundation of Jiangsu in China [No. BK20161532, BK2015914 and BK20151526]; Jiangsu Provincial Programs for Marine Science and Technology Innovation [HY2017-5]; CEReS Oversea Joint Research Program, Chiba University [No. CI19-103]; National Program on Global Change and Air-sea Interaction [No. GASI-03-03-01-01]; Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD) and Postgraduate Research & Practice Innovation Program of Jiangsu Province [KYCX17_0887].