New Index for Winter Temperature of the Korean Peninsula and the East Asia based on the atmospheric teleconnection patterns

Abstract:

This study proposes a new index for monitoring and predicting winter temperature of the Korean Peninsula based on dominant atmospheric winter teleconnection modes and the utilization of the index is extended further to representing the East Asia Winter Monsoon (EAWM). Among the teleconnection modes it is found that both East Atlantic (EA) and Western Pacific (WP) modes are most strongly correlated with the Korean winter temperature in a way that the modes are partly associated with change in sea level pressure (SLP) around the Korean Peninsula. Particularly, the EA and WP modes are related with SLP variation over both Siberian High region and the Kuroshio extension region to the east of Japan, respectively. Based on this relationship, the two boxed regions representing the northeast-southwest SLP gradients are determined for the new index, which is found to be related with the EAWM circulation. The SLP gradients control the intensity of surface winds blowing into the Korean Peninsula from the Siberian regions which can transport cold air. The index shows the best performance in representing winter climate not only for the Korean Peninsula but also for the East Asia among the SLP-based EAWM indices. Furthermore, the new index maintains a better correlation with the winter temperature of both the East Asia and Korea over a certain period of years (i.e., running 30 year periods) than other SLP based EAWM indices and also shows good performance in delineating extreme cold/warm winters. The predictability of the new index and its usable potential for winter temperature prediction in coupled climate models are assessed and discussed further.