한반도 주변해 해수면 계절변화 성분의 공간 변동성 및 역학

Abstract

The analysis of seasonal sea level variation in surrounding seas to Korean peninsula revealed that there exist some systematic pattern for the Sa amplitude varying from 20 to 10cm, depending upon the regions such as the Yellow Sea, South Sea and East/Japan Sea (EJS). Results from the analysis of coastal tidal data are presented as well as the analysis result from the satellite altimetry data of Topex/Poseidon. The physical factors, such as atmospheric force and thermosteric force, to influence the seasonal variation of sea level are examined in order to understand the mechanism of spatially systematic variation of the seasonal sea level variation component Sa. The spatial distribution of Sa amplitude by inverse barometric effect varies 10cm to 8cm from the Yellow Sea, through South Sea, to the EJS, respectively. This inverse barometric force alone does not explain the amplitude variation over the surrounding seas to Korean peninsula. Additional contribution is from the origin of sea level change by the thermosteric effect. Naturally we focus upon the contribution of thermosteric sea level to the observed Sa variability in the Yellow and East/Japan Seas. In the Yellow Sea the Sa amplitudes by the thermosteric effect are about 5 to 7cm from 10 to 20 year data analysis, and the phase of peak amplitude occurs in August by seasonal solar radiation, similarly to the phase lag of early July by inverse barometric effect. Meanwhile, the amplitude contribution by the thermosteric sea level in the EJS is 3 to 4cm, and Sa peak lags by about 50°than in the Yellow Sea, due to possibly different physical phenomenon from the Yellow Sea in summer season. It is known that the cold water mass from the northern EJS flows toward the southern and southwestern direction, which may drive a different TSL contribution from the Yellow Sea where solar radiation is the main forcing to water column. Summation of two component with representative phase lag explains reasonably better the observ