Analysis of Annual and Spatial Patterns of Czcs-Derived Pigment Concentration on the Continental Shelf of China

The combination of a population of more than 1.2 billion people in China, Taiwan and Hong Kong and recent rapid industrialization has placed a very heavy burden on the region\u27s coastal environment. Algal blooms and red tides pose a serious threat to public health, fisheries and the aquaculture industry. Consequently, a thorough examination of the temporal variations in phytoplankton pigment concentrations in coastal water on a large scale is necessary. This study examined the annual and geographic variations of pigment concentration on the continental shelf of China from 1978 to 1986. All the available Coastal Zone Color Scanner (CZCS) images (2139 scenes) from the Nimbus satellite were screened and examined. A total of nine annual composite images were generated. Annual average pigment concentrations were then examined for three transects along the shelf. Significant geographic variation of pigment concentrations was revealed. A distinctive high concentration belt of about 50 km wide exists along the coastline of China, and a large plume of high pigment concentration was observed to extend nearly 500 km to the east from the Yangtze River. This plume merged with high pigment concentration water along the coast of the yellow Sea. A basin-wide gyre rotating clockwise appeared in the center of the Yellow Sea in 1986. Pigment concentrations were high in the Yellow Sea (about 1-2 mg m-3) and decreased seawards and southeastwards with a minimum value in the Philippine Sea (about 0.2 mg m-3). Interannual variation in the study area was also revealed. Annual pigment concentration reached a peak in 1981. Generally, annual pigment concentrations were relatively higher and more variable in the inner shelf and in the northern area whereas they were lower and less variable in the outer shelf and in the southeast region