Apparent spectral types and characteristics of Pearl River Estuary

With complex spectral characteristics, the Pearl River Estuary sea area belongs to typical Case Ⅱ waters, which has always been a hot area researched by domestic scholars.Based on the apparent spectral data detected from four voyages in Pearl River Estuary in spring (May), summer (August), autumn (November) and winter (February) in 2014, this paper illustrated the types of remote sensing reflectivity and its spatial and temporal distribution characteristics.The results suggest that there are five types of remote sensing reflectivity in the four seasons in Pearl River Estuary, and each type of the spectrum has typical regional and seasonal variation characteristics.The peaks of the spectrum range from 450 nm to 575 nm, with the variation of the seasons, i.e., Type A perennially distributed in Pearl River estuary; Type B distributed in mixed transitional waters outside the Pearl River Estuary in winter and spring; Type C is mainly distributed in the offshore area with deeper depth; Type D distributed in the waters near Wanshan Islands in spring and summer and Type E similar to that of Case Ⅰ waters.The analyses show that the spectral pattern of the five spectral types are dominated by different water quality parameter.The research has shed new light on remote sensing retrieval of color elements and further exploration of the spectral characteristics in our coastal Case Ⅱ waters such as Pearl River Estuary.