A study on the variation of the SST distribution over the southern Yellow Sea and East China Sea using NOAA/AVHRR data

Abstract

The 5-year NOAA/AVHRR data set was used to study the SST distribution and to derive the dominant sea surface temperature (SST) pattern over the Yellow and East China Sea (YECS). EOF analysis was applied to this data set for understanding the temporal and the spatial dominant SST variation. The SST pattern from the satellite data varies with seasonal surface heating and cooling in YECS. The SST patterns during from fall to next spring are roughly composed of three parts. The first part is the low temperature coastal zone (south coast of Korea, Mokpo and Jindo; east coast of China, vicinity of south Chanejiang river mouth). The second part is the high temperature zone on adjacent area of Kuroshio. The third part stands in between the first and second, which has a relatively complicated temperature structure consisting of a cold tongue sandwiched in between two warm tongues. In summer, the SST distribution is nearly uniformed due to strong heating of sea surface except some strong vertical mixing zone (Mokpo and Jindo) by tide. In winter, the SST patterns are pronounced along the bottom topography because the sea surface is strongly cooled and mixed by winter monsoon. In the YECS, the lifetime of the tongue-like SST pattern observed from satellite data sequence was found to be 9 months, which began to be formed in mid-October and lasted to next mid-June. The spatial mean structures and the first temporally demeaned EOF contained in the satellite data sequence describe the seasonal cycle in SST and thermal gradient between north and south of the study area. The range of seasonal SST variation from the first mode of temporally demeaned EOF, 93.4% is greater in the southern Yellow Sea and northern East China Sea than in the Kuroshio region.