Estimation of primary production in the northwestern part of the Sea of Japan by ship- and satellite-based observations

Abstract

In this paper, we analyzed data of POI FAB RAS cruise (No. 33) held on «Akademik M.A. Lavrentyev» vessel in the northwestern part of the Japan Sea in May 2004 and compared them with satellite derived data from Climate Change Initiative Ocean Colour (CCI-OC) and Ocean productivity databases. The following in situ data were used for the analysis: CTD-data, assimilation number, nutrients (P, N, Si) and chlorophyll a (Chl). Ship assessments of Chl in the first optical layer were in average 0.5±0.58 mg/m3, while satellite Chl were nearly twice more – 0.95±0.36 mg/m3. Ship assessments of primary production (PP) were 1870±900 mg C/m2day that is 1.5 times larger than satellite derived data - 1226±432. Vertical profiles of nutrients, temperature and Chl showed that main mass of Chl was concentrated in a layer from 20 to 45 m, where the main production is formed. According to values of assimilation number, main production formed in a layer of 0-55 m in the south of the region and 0-30 m in the north. Weak correlation between ship and satellite PP values found in this paper may be explained by low accuracy of satellite derived estimation.