| According to the consistent Meiyu standard,which published by The Prediction and Network Ministry of China Meteorological Administration in 2014,the daily precipitation data of Meiyu monitoring area and daily reanalysis data of NCEP/NCAR.The onsets,withdrawals,length,rainfall and intensity of Meiyu were calculated.The results are as follows:(1)The mean onsets and withdrawals of JiangNan area are earliest.(2)The trends of the length and the intensity of the Meiyu in the middle reaches of the Yangtze River and the lower reaches of the Yangtze River are consistent.In the late 1960s,the length became longer and the intensity intensified,and then it was in a relatively stable state until the late 1990s,the length became shorter and the intensity weakened.(3)The onsets and withdrawals are highly correlated.The relationship between outsets of Meiyu and other features of Meiyu is closer than the relationship between onsets of Meiyu and them in the Meiyu monitoring area,the Jianghuai area and the middle reaches of the Yangtze River.However,The Jiangnan area is a different story.(4)Comparing to the twice northward jump of Western Pacific subtropical high,the mean onsets are coordinated with the occurrence of the first time of northward jump of Western Pacific subtropical high.The mean withdrawals are 10-15 days earlier than the occurrence of the second time of northward jump of Western Pacific subtropical high.(5)Before and after mean earlier onsets,on earlier onsets year of Meiyu,Western Pacific subtropical high is strong,northwest,Western Pacific subtropical high ridge is beyond 20° N,on late onsets year of Meiyu,Western Pacific subtropical high is weak.Before and after mean late withdrawals,on earlier withdrawals year of Meiyu,Western Pacific subtropical high ridge is beyond 30°N,on late withdrawals year of Meiyu,Western Pacific subtropical high is strong,the west part of Western Pacific subtropical high ridge is near 30°N. |
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