Abstract :
The amount of phytoplankton, usually expressed as concentration of chlorophyll-a, is one of the most important parameters in describing state of water bodies. The amount of chlorophyll-a in coastal waters is extremely variable both spatially and temporally. Therefore, the classical monitoring programs, which are based on infrequent measurements in a few fixed stations, or ships of opportunity cannot provide spatial and/or temporal coverage needed to determine the amount of chlorophyll-a. Remote sensing could be the tool to provide necessary information. Chlorophyll retrieval algorithms proposed by different authors are used by space agencies to provide satellite derived chlorophyll products. These products are relatively accurate in Case I (oceanic) waters. However, they often fail in Case II (coastal) waters. We have compared MODIS chlorophyll product with in situ measurements carried out in the frame of Estonian National Monitoring Program. The results indicate that correlation between satellite derived chlorophyll estimates an in situ measurement results is very pure in Estonian coastal waters and there is strong need to develop local chlorophyll retrieval algorithms. This is a task our group is currently working on.
