Fluctuations of satellite-derived chlorophyll concentrations and optical indices at the Southern Yellow Sea

Time series of chlorophyll-a concentration (chl a), backscattering coefficient at 490 nm (b(bp)(490)) and spectral slope of b(bp) (gamma) derived from satellite imagery of ocean color were used to study the aquatic ecosystem of the Southern Yellow Sea during the time period of 1997-2007. Our study indicated that chl a increased in offshore waters by 0.02 mg m(-3) y(-1) (p < 0.05), in contrast to a decline observed in the middle and low-latitude global waters. b(bp)(490), a proxy of total suspended particulate matter concentration did not have any significant trend, while gamma, a proxy of the relative proportion of small-sized and larger particles in the surface ocean, decreased significantly. Annual spring phytoplankton blooms occurred in nearshore and offshore waters of the central Southern Yellow Sea; while autumn blooms only occurred in nearshore waters.