Seasonal variability of the backscattering coefficient in the Mediterranean Sea based on Satellite SeaWiFS imagery

The annual progression of the particulate backscattering coefficient, b(bp), within the whole Mediterranean sea is examined from satellite remote sensing and inverse modeling for the first time. This study reveals that bb, is roughly distributed uniformly over the Mediterranean that differs from the well known east-west gradient in terms of chlorophyll concentration, Chl. In contrast to Chl, b(bp) is also weakly variable along the seasons, and presents different extrema. These observations are attributed to the presence of high concentrations of submicrometer particles such as detrital particles, heterotrophic bacteria and also possibly mineral particles from aeolian inputs. The interpretation of b(bp) in terms of particulate organic carbon concentration, POC, is discussed, and a relationship between bbp and POC is developed. Application of our algorithm to SeaWiFS data indicates that the satellite estimates are in good agreement with surface POC measurements.