Cold Vortex over Northeast China and Its Climate Effect

Based on the long-term dataset of cold vortex over Northeast China derived from automatic method of detection and track, interannual variability of cold vortex over Northeast China, the effect of its persistent activities on regional climate, and the associated large-scale circulation anomalies are investigated. The results show that the cold vortex has a considerable interannual variability, but no significant long-term trends. Persistent activities of cold vortex have a major oscillation with a period of about 2.5 a. Frequent occurrences of cold vortex can cause a significant negative air temperature anomaly over Northeast China for all seasons and lead to more local rainfall in spring and summer seasons. There are likely more rainfalls over the Yangtze River basin when the summer cold vortex is more frequent. In winter when the cold vortex occurs more frequently, most of China experiences lower air temperature and less rainfall, which is highly related to strong East Asian winter monsoon. In the summer of more cold vortices, deep dipole-like geopotential height anomaly maintains over East Asia, the upper-level jet stream shifts southward and is strengthened slightly, and the lower-tropospheric anticyclonic anomaly over the western North Pacific and the easterly anomaly over high latitudes facilitate the water vapor flux to be convergent over the Yangtze River basin and Northeast China, respectively.