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 curve between annual average beginning day of the CV rainy period and multi-year average beginning day, and (b) the curves of years with obviously early and late beginning dates of the annual CV rainy period.