Objective identification research on cold vortex and mid-summer rainy periods in Northeast China*
Gong Zhi-Qianga)†, Feng Tai-Chenb), Fang Yi-Hec)
       
(a) Difference curves between the annual average beginning (ending) date number of the MS rainy period and the multi-year average beginning (ending) date number of the MS rainy period, and the curves of the years with obviously early and late beginning (b) and ending (c) dates of the annual MS rainy period.