Objective identification research on cold vortex and mid-summer rainy periods in Northeast China*
Gong Zhi-Qianga)†, Feng Tai-Chenb), Fang Yi-Hec)
       
Distribution diagram of multi-year average 500-hPa subtropical high pressure in different periods. In the figure, numbers 1–4 represent the 588 contours corresponding to P1 to P4 respectively.