The Discussion on the Division Standard of the Onset and the Ending of Meiyu Season in Hubei Province

In this paper,by using the NCEP's objective analysis data and the every day rainfall pattern data of Hubei's different regions, the re-division standard about the onset and the ending of Meiyu season in Hubei is compared with the previous division standard got from 1980 to 2007, and the contradictions or differences between them are discussed. Considering the weather features, meteorological characteristics and forecasting service needs, the new division standard of Meiyu season is supplemented with the following: (1) The date when the ridge line of subtropical high at 150 hPa at 120°E moves north crossing 20°N,and keeps stably and rain in the east of Hubei in the next 3days and more, rainfall coding is over 9 in the east of Hubei and Jianghan plain is onset date of Meiyu. If the concatenation overcast and rainy days is over 3 days and the rainy day keeps in the next days, the begin date of the overcast and rainy is the onset of Meiyu. (2) The date when the ridge line of subtropical high at 150 hPa at 120°E moves to the north of 26°N and keeps stably in the next 3 days and more, and the rainfall coding is × or less than 1 in the east of Hubei and Jianghan plain is the ending date of Meiyu, or the date that rainfall ended before the subtropical high controlling this area continuously is the ending date of Meiyu.