Main regional spatial modes of winter air temperature variations in eastern China and their relationship with atmospheric circulation
Based on the daily air temperature data of 519 stations in China from 1956 to 2017,this paper dis-plays two main regional spatial modes of winter surface air temperature anomalies in eastern China through the rotating empirical orthogonal function analysis method,and studies the relationship between them and atmo-spheric circulation. The results show that these two regional spatial modes are relatively stable. The first mode is manifested as the anomalous low temperature in most parts of southern China,which is called southern mode. The extreme cold centers of this mode are located in the south and southeast coastal areas. The anomalous tem-perature signals of the second mode are mainly concentrated in the northeast China,which is called the northeast mode. There is a significant negative correlation of the time series of southern mode with sea surface temperature in the equatorial central Pacific,and a significant positive correlation with the opposite variation mode of East Asian winter monsoon in the south and north,respectively. When the sea surface temperature in the equatorial central Pacific is anomalously cold in winter,the southern part of East Asia shows a strong low-level northerly wind causing anomalously low temperature in most parts of southern China. At this time there is no significant northerly wind anomaly in the northeastern Asia. By contrast,the winter Arctic Oscillation is significantly relat-ed to the northeast low-temperature mode. When the Arctic Oscillation is in its negative phase,the cold high pressure is mainly concentrated in the polar region,and the northeasterly wind prevails on its east side,leading to anomalously low winter air temperatures in Northeast China.
winter air temperaturespatial patternthe "North-South reverse" mode of East Asian winter monsoonArctic Oscillation
NETL
NSTL
万方数据
