SCHEMATIC PREDICTIVE MODEL FOR EXTREMELY SEVERE COLD MONTHS IN SOUTH CHINA WINTER ──500hPa geopotential field and SST field

The work sets the time for the occurrence of extremely severe cold months over the past 45 years in South China winter and studies the 500 hPa geopotential fields and SST fields in and before the months. The months have similar 500 hPa heights; higher in the north and lower in the south in the Asian-Pacific region, indicating meridianal evolution of the circulation. The work also gives the anomalies for months that have significant differences in the 500 hPa field in periods prior to the extremely severe cold months. Persistence is found in the SST anomalies in the current month and 1-6 months before them : January is featured by the EI Nino event and February and December by La Nina.