Manifestations of the rim current, coccolithophore blooms, and continental runoff in the long-term monthly mean distributions of satellite reflectance coefficients of the Black Sea

Abstract

Based on the archived data of the ocean color scanner MODIS-Aqua for 2003–2011, we constructed the long-term monthly mean distributions of the reflectance Rrs of the Black Sea for April, May, June, and September in order to visualize the contributions of seasonal factors to the long-term variability of the basin’s images. In April, the Rim Current’s branch west of 34° E is visualized by higher Rrs in different regions of the visible spectrum due to the transport of suspended matter caused by intensification of the Rim Current during the winter-spring period. During the June coccolithophore “blooms,” the long-term Rrs level is 2–3 times higher when compared to the previous and subsequent months. This excess is particularly considerable outside the shelf and coastal areas. The open sea Rrs distribution in June features horizontal inhomogeneity. The seasonal trend of the Rrs spectra on the Black Sea NW shelf is explicitly related to the annual cycle of the continental runoff effects.