Distribution of Changjiang Diluted Water (CDW) and interannual variation in this decade detected by satellite chlorophyll-a

Abstract

Summer satellite chlorophyll-a distribution in the East China Sea during last decade was analyzed. With statistical analysis, K-means clustering, proper satellite chlorophyll-a concentration indicating the Changjiang Diluted Water (CDW) was found. During 1998-2007, the distribution of CDW controlled by the Changjiang summer freshwater discharge (SFD) showed significant interannual variations. The Sea-viewing Wide field-of-view Sensor (SeaWiFS) chlorophyll-a showed that interannual variations of the spatial distribution of high satellite chlorophyll-a (>0.9-0.4 mg m-3) were well corresponded with distribution of low salinity CDW (<30-32), and that interannual variation of the CDW area was associated with the interannual variation of SFD. Correlation analysis indicated that low salinity CDW area, corresponding to high satellite chlorophyll-a area, spread eastward in the East China Sea with 1 to 2 months time lag from the discharge.