A Diagnostic Study of Northeast Cold Vortex Heavy Rain over the Songhuajiang-Nenjiang River Basin in the Summer of 1998
1998年松嫩流域东北冷涡大暴雨过程的诊断分析

By using the diagnostic analysis method, studied are the general circulation conditions of the northeast cold vortex heavy rainstorm over the Songhuajiang-Nenjiang River basin in the summer of 1998, the natures of the precipitation, the features of moisture transportation, and the relationship between the low frequency over East Asia and the persistent rainfall. The results show that the five northeast cold vortex heavy rainstorm cases over the Songhuajiang-Nenjiang river basin in the summer of 1998 are of most representative. They result from different atmosphere circulation patterns. Thus, with different synoptic background and precipitation natures, they play quite different roles in the formation of the flood. Especially, the Asian summer monsoon moisture transportation and the 30-50 day, 10-20 day low frequency oscillations play important roles in the persistent rainfall.