摘要
梅雨期是江淮流域夏季降水最为集中的时段。先前研究提出的从时域上寻找极端降水过程的EID方法,可用来确定梅雨雨期的开始和结束及梅雨的强度。该方法含有一个介于0~1之间的可调参数a,通过对其设定不同的值,可确定出一年中不同时间尺度的降水最为集中的时段(雨期)。以南京的梅雨为例,通过试验将参数a取值为0.10,用EID方法获得了气候态的梅雨雨期,它于6月19日开始,7月12日结束,这大体与传统认定的梅雨期相符。对于逐年梅雨雨期的确定,情况稍有复杂。在用同样的方法确定出各年的强降水时段后,在62 a里去掉了12个异常的年份,包括雨期太长和太短、及太早和太晚的年份。然后对其余50个梅雨较为典型的年份进行平均。结果显示,平均的入梅日期为6月24日,平均的出梅日期为7月14日,平均雨期为20 a,这也大体与传统认定的结果相符。
The Meiyu season has the strongest rainfall during summer period over the Yangtze-Hua- ihe River Basins. The EID method was used to determine the starting and ending of the Meiyu season. It contains an adjustable parameter a, which varies between 0 and 1. Through setting appropriate values to the parameter, the strong rainfall period of different time scales can be determined. For the Meiyu in Nanjing, the EID was used to capture the climatic Meiyu season through giving a value of 0.10 for the parameter a. It starts from June 19 and ends on July 12, which is consistent with the conventional results. The EID method is also used to determine each strong rainfall period of 62 years. The 12 years were omitted, in which the rainfall period is too long or too short, and appears too early or too late. The average of the remaining 50 years indicates that the mean onset date of the strong rainfall is June 24 and the mean end date is July 14, which is also consistent with the conventional results.
出处
《气象科学》
北大核心
2018年第1期37-45,共9页
Journal of the Meteorological Sciences
基金
公益性行业(气象)科研专项(重大专项)(GYHY201506001-1)
国家自然科学基金项目(41275092)
关键词
梅雨
雨期的确定
EID方法
Meiyu
Determining Meiyu period
EID approach
