ESTIMATION OF VERTICAL DISTRIBUTION OF CHLOROPHYLL a OFF EAST HOKKAIDO BY GAUSSIAN CURVE FITTING (15th Symposium on Polar Biology)

Sea truth data on the concentration of chlorophyll pigments were used to determine the empirical relationship between surface chlorophyll a concentration and parameters derived from a Gaussian curve for a possible development of a local algorithm of primary production in the western subarctic North Pacific Ocean. Data were obtained from the line between 39°N, 146°45\u27E and 42°50\u27N, 144°50\u27E from April 1990 to July 1991. One optical depth (1/k) can be estimated from the concentration of chlorophyll a (B_c) at the surface depth. Surface Bc can be estimated from B_c+B_p (concentration of pheopigments) in one optical depth. The background concentration of chlorophyll a (B_o), the depth of the subsurface chlorophyll maximum (z_m), and the total biomass above the background (h) which control the Gaussian curve can be determined from the surface Bc. Therefore, once surface Bc is obtained, the vertical profile of Bc is determined. However relative variability in the estimated values from the surface Bc can be high when the standing stock of chlorophyll a is lower than 300 mg Chl. a m^. This may suggest that the present model can be applied only to a relatively productive area. The standing crop of chlorophyll pigments in one optical depth, which can be estimated from the ocean color obtained from the satellite, would be useful to determine the standing crop of chlorophyll pigments in the euphotic layer