| Yellow substance, namely coloured dissolved organic matter (CDOM), is one of the three elements of water color remote sensing. Its biochemical conservation can well reflect the transport process of pollutants. The inherent optical properties of CDOM in CASE Ⅱ waters have always been the hot topics both at home and abroad. Zhanjiang Harbor is a natural deep-water port. Affected by busy port transportation, offshore steel and iron production, petrochemical industries, urban life and sewage discharges, Zhanjiang Harbor is characterized by serious eutrophication in recent years. The water quality is rating at four or inferior four category frequently. It is of great significance to study the CDOM optical properties of waters in this area for better understanding the intrinsic optical properties and the detection of remote sensing. A survey on CDOM and other elements of the Zhanjiang Bay was conducted in May 2017, which indicated that the variation range for ag(355) in Zhanjiang Bay waters in spring is at 0.69-2.3 m-1, showing a decreasing trend from north to south and from west to east. The variation range of S275-295 value is at 16.15-20.16×10-3 nm-1, the distribution of the horizontal space of CDOM is roughly speckled, characteristic of coming from typical land source. Based on landsat-8 OLI band characteristics, the CDOM retrieval model of Zhanjiang Harbor is constructed through the band-ratio method, and the correlation coefficient can reach 0.84. The research indicates that the remote sensing method has high reliability based on Landsat-8 satellite CDOM for offshore harbors. |
