Water Transparency (Secchi Depth) Monitoring in the China Sea with the SeaWiFS satellite sensor

摘要

Water transparency (Secchi depth) is a basic parameter that describes the optical property of water, and it is a traditional item measured in situ. The traditional method of monitoring water transparency is the in-situ measurement by ship. However, because of its inherent shortcoming, this in situ method can not satisfy the requirement of the large-scale, quick and real-time monitoring of the water transparency. Therefore, it must be combined with the remote sensing technology to fulfill the monitoring of the water transparency. This paper studies the water transparency monitoring in China Sea by using SeaWiFS satellite sensor. First, the inversing algorithm of water transparency is introduced briefly, which based on the radiative transfer theory and bio-optical model of water. Second, the accuracy of the algorithm is validated by using the large-scale in-situ data from the Japan Meteorological Agency (JMA), which covered most of the Northwest Pacific ocean. The result shows the inversing relative error of water transparency is 22.6% by using the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) data, and it is even better in the open sea. Third, using this algorithm and SeaWiFS data, a remote sensing product data set of water transparency in China Sea was generated. Finally, we present the analysis of seasonal distribution and fluctuation patterns of water transparency in China Sea by using the generated remote sensing product collection of water transparency.