2015 Volume 35 Issue 4 Pages 245-259
Standard SeaWiFS and MODIS-derived chlorophyll a concentrations (chl.a) were verified in Ise-Mikawa Bay by more than 300 in situ data. Results showed that more than 80% of match-up chl.a data in offshore area were within the range of 0.5-2 times in situ chl.a for both MODIS and SeaWiFS. However, only 60% were within the range in the bay. Log_RMS of MODIS and SeaWiFS were 0.320 and 0.299, respectively. MODIS remote sensing reflectance (Rrs) after standard atmospheric correction algorithm showed large underestimation, specifically at the short wavelength, and more than 50% of the Rrs(412) data was negative during spring. A simple correction method for MODIS and SeaWiFS Rrs was developed using an empirical relationship between in situ Rrs(412) and Rrs(547) or Rrs(555). The in-water algorithms were also optimized with local in situ data. Finally, the satellite chl.a in the bay was improved and more than 70% became within the range of 0.5-2 times of in situ chl.a. The log_RMS of MODIS and SeaWiFS became 0.251 and 0.271, respectively. Since a similar empirical relationship between the Rrs was observed in Ariake Bay, East China Sea, and Lake Biwa in certain conditions, it is expected that the Rrs correction method might also be applicable to those regions.
