Long term pattern of primary productivity in the East/Japan Sea based on ocean color data derived from MODIS-aqua

Abstract:

A recent decadal pattern of annual primary production was analyzed in the East/Japan Sea (hereafter East Sea) estimated by the size-fractionated primary production estimation algorithm based on ocean color data derived from Moderate-Resolution Imaging Spectroradiometer (MODIS-aqua). The mean daily primary productivity was 676.1 mg C m-2d-1 (S.D = ± 221.2mg C m-2 d-1 ) in the East Sea during the study period from 2003 to 2012. Based on the daily primary productivity, the annual primary productivity was 246.7 g C m-2 y-1 (S.D = ± 22.4 g C m-2 y-1 ) in the East Sea. Especially, we found different spatial and temporal patterns in primary productivity in the northern and southern regions divided by subpolar front in middle of the East Sea. The mean annual primary productivity in the southern region was 262.7 g C m-2 y-1 (S.D = ± 17.6 g C m-2 y-1),whereas the mean rate in the northern region was 230.8 g C m-2 y-1 (S.D = ±13.5 g C m-2 y-1). During the observation period, remarkable decreases in the annual primary productivity were observed in the northern and southern regions from 2003 to 2012. The southern region had a positive correlation between annual primary productivity and Pacific Decadal Oscillation (PDO) index, whereas that the northern region had a positive correlation between productivity and ElNino Southern Oscillation index. The recent decline trend in the annual primary production in the East Sea during 2003-2012 period might be a part of the oscillation pattern of the annual primary productivity governed by PDO, not a solely decreasing trend.