Large-Scale Circulation Features Typical of Wintertime Extensive and Persistent Low Temperature Events in China

A pair of northeast-southwest-tilted mid-tropospheric ridges and troughs on the continental scale was observed to be the key circulation feature common among wintertime extensive and persistent low temperature events (EPLTE) in China. During the persistence of such anomalous circulations, the split flow over the inner Asian continent and the influent flow over the southeastern coast of China correspond well to the expanded and amplified Siberian high with tightened sea level pressure gradients and hence, a strong, cold advection over southeastern China. The western Pacific subtropical high tends to expand northward during the early stages of most EPLTEs.