초록
The results of our observation in May 2000 indicated that the SeaWiFS algorithm (O'Reilley et al., 1998), which was adopted for OSMI data processing, overestimated the actual chlorophyll values. This was rather unexpected in that there were good reasons to expect that the bio-optical properties of East/Japan Sea belonged to Case 1 water and in such case, the OC2 algorithm would give unbiased estimates of actual chlorophyll a values. In November 2000, a cruise conducted bio-optical surveys in the same area. This time we added HPLC (High Performance Liquid Chromatography) method for measuring chlorophyll a concentration to the standard fluorometric method, which we hale been using during the past Fluorometric method with acidification is known to result in under/overestimation of chlorophyll values in many parts of the world oceans, while it is easier and cheaper than HPLC method. To our surprise, the comparison of HPLC chlorophyll and fluorometric chlorophyll values show that fluorometric values gave an underestimation up to 50%. This error was due to the presence of accessory pigments such as chlorophyll b. Considering this error, our precious result of May 2000(Yoo et al., 2000) might have to be reinterpreted. Calculation of reflectance at 490 and 555nm, however, indicated that this is not still enough to explain the discrepancies.