Patterns of seasonal and inter annual changes of surface chlorophyll concentration in the Black Sea revealed from the remote sensed data

Several years of CZCS-measured surface pigment's concentrations in the Blac k Sea are analyzed to appraise the seasonal and year-to-year fluctuations o f phytoplankton biomass and understand the causes of these fluctuations in terms of the Black Sea's general dynamics. The pattern of seasonal variatio ns is typical for subtropical rather than temperate regions. The range of t he absolute value of plant pigment surface concentration measured by remote sensing does not differ greatly from the values measured by direct methods . The pattern of year-to-year variations seems to correlate with cyclic osc illations of winter air temperature. In western shallow regions it is also correlated with the Danube discharge intensity. More intensive winter-sprin g blooms and a slightly lower level of pigment concentration during warm se ason are typical for years of with a mild winter. The causes of there regul arities seem to be the peculiarities of hydrological and meteorological reg imes of the Black Sea. The intensity of winter-spring bloom of phytoplankto n appears to depend on hydrological mechanism (i.e., the intensity of water mixing during winter period due to thermic convection and wind mixing) rat her than the illumination intensity. (C) Elsevier Science Inc.