남중국해 여름몬순과 ENSO와의 가능한 상관관계

Abstract

This study analyzed a correlation between South China Sea summer (June to September) monsoon (SCSSM) and the ENSO for the last 32 years (1979 to 2010). There was a correlation that the higher (lower) the SST in the <TEX>$Ni{\tilde{n}}o-3.4$</TEX> region was, the weaker (stronger) the SCSSM intensity was. To identify the reason for this correlation, a difference of means between 8 El <TEX>$Ni{\tilde{n}}o$</TEX> years and 8 La <TEX>$Ni{\tilde{n}}a$</TEX> years (June to September). The analysis on the difference between two groups with respect to the 850 hPa stream flows showed that there were anomalous huge cyclones in the subtropical Pacific in the both hemispheres so that cold and dry anomalous northerlies were strengthened in the South China Sea relatively while anomalous westerlies were strengthened from the Maritime Continent to the off the coast of Chile. The analysis on the difference between two groups with respect to the 200 hPa stream flows showed that the opposite anomalous pressure system pattern to that in the 850 hPa stream flows were shown. In the subtropical Pacific of the both hemispheres, anomalous anticyclones existed so that anomalous easterlies were strengthened from the Maritime Continent to the equatorial central Pacific. Considering the anomalous atmospheric circulations in the upper and lower layers of the troposphere, upward airflows from the equatorial central and eastern Pacific were downward in the South China Sea and the Maritime Continent, which was a structure of anomalous atmospheric circulations. This means that the Walker Circulation was weakened and it was a typical structure of atmospheric circulations revealed in El <TEX>$Ni{\tilde{n}}o$</TEX> years.