First look at the particulate absorption coefficient in the surface water of the subtropical East China Sea in spring

Abstract

During a KEEP-II expedition in the East China Sea in May 1996, absorption spectra of near surface particulate matters were measured at 38 stations. The total pigment concentrations ranged from 0.2 to 7 mg m-3. The common absorption peaks for chlorophyll a, centered at 440 nm and 675 nm, were observed at most stations. However, four exceptions were found in the low salinity China Coastal Water. The 440 nm absorption peak shifted to 410 nm in these four samples. Very high correlation was found between pigment concentration and the particulate absorption coefficient at several visible bands which are often used for satellite spectrometers. It is noted that the relationship between the chlorophyll a specific absorption coefficient at 440 nm and the chlorophyll a concentration observed in the East China Sea is different from that observed in the central subtropical Pacific and the Gulf of Mexico. The particulate matter int he East China Sea has a slightly higher absorption coefficient than the latter.