リモートセンシングとGISのジャーナル

概要

Water Quality Seasonal Variability (2000 to 2015) in Yangtze River Estuary and Its Adjacent Coastal Area

Xianping Yang, Leonid Sokoletsky* and Hui Wu

Three separate algorithms: 1) Modified NIR-SWIR atmospheric correction, 2) Suspended sediment concentration (SSC), and 3) Diffuse attenuation coefficient at 490 nm, K_d (490) were developed and used for mapping SSC and K_d (490) for the East China natural waters. A geographic area located between 27-35°N and 119-125°N was selected to analyze wet (flood) and dry seasons from 2000 to 2015. Remote sensing acquisition has been realized using the MODIS/Terra and MODIS/Aqua satellite sensors. Results showed large differences between these seasons in terms of spatial pattern of SSC and K_d (490) levels: SSC and K_d (490) values were higher during the dry season than during the flood season in the most part of area for most of the area. The area with high SSC>80 gm^-3 [or, correspondingly, K_d (490)>2.3 m^-1] within the Subei Bank of the Yellow Sea and the Zhejiang coastal area was estimated to be almost twice as large during the dry season when compared to the wet season. Results also revealed an impact of the Three Gorges Dam power station on the water quality in the Yangtze River Estuary.