Statistical analysis of NOAA/AVHRR high resolution weekly SST in the East Sea: Regional variability and relationships with ENSO

Abstract

The characteristics of SST variability in the East Sea are analyzed using NOAA/AVHRR weekly SST data with about 0.18°x0.18° resolution (1981∼2000) and reconstructed historical monthly SST data with 2°x2° resolution (1950∼1998). The distinct feature of wintertime SST is high variability in the western and eastern parts of 38°∼40°N latitudinal band, which are the northern boundary of warm current in the East Sea during winter. However, summertime SST exhibits variability with similar magnitude in the entire region of the East Sea. The analysis of remote correlation also shows that SST in the East Sea is closely correlated with that in the region of Kuroshio in winter, but in summer is related with that in the western and eastern regions of the same latitudes. From these results it is postulated that the SST variability in the East Sea may be related with the variations of East Korean Warm Current and Tsushima Warm Current in winter, but in summer probably with the variations of atmospheric components. In the analysis of ENSO related SST anomaly, a significant negative correlation between SST anomalies in the East Sea and SST anomalies in the tropical Pacific is found in the months of August-October (ASO). The SST in the ASO period shows more significant cooling in El Nino events than warming in La Nina events. Also, the regional analysis shows by the Student's t-test that the negative SST anomalies in the El Nino events are more significant in the southwestern part of the East Sea.