On the spatial–temporal variations in the chlorophyll-a concentration on the Peter the Great Bay shelf during the winter–spring phytoplankton bloom according to satellite and subsatellite data

Abstract

Chlorophyll-a concentration (Cchl) variations in the cross section within and outside the Peter the Great Bay shelf during different stages of the winter–spring phytoplankton bloom in 2003–2005 has been considered based on a ship (obtained during the R/V Akademik M.A. Lavrent’ev voyage of February 26 to March 9, 2003) and MODIS-Aqua spectroradiometer and the SeaWiFS color-scanner satellite data. A comparison of the Cchl variability obtained from the ship and satellite data indicates that these data are inconsistent. According to satellite data obtained at the MUMM atmospheric correction, the Cchl variability is distorted less than the NIR-correction data. Studying the variations in the coefficients of light absorption by the detritus and yellow substance (adg) and light backscattering by suspended particles (bbp), Cchl, chlorophyll-a fluorescence (Fchl) according to the satellite data allow us to state that the variations in the discrepancy between the satellite and ship Cchl values are mainly caused by the variations in the content of the detritus and yellow substance in water. Based on the satellite data, it has been revealed that the adg values increase with increasing wind mixing after the phytoplankton bloom (about 2–5 km areas where the adg, Cchl, Fchl, and bbp values abruptly increased in 2005, apparently due to eddy formation). It has been indicated that the Fchl characteristic, which is close to Cchl, increases when the favorable conditions for the phytoplankton bloom deteriorate. Therefore, this characteristic cannot be used to identify Cchl under the indicated conditions.