近46 a重庆汛期极端降水量异常特征

利用重庆33站1961-2006年汛期(5-9月)逐日降水资料,定义了不同台站的极端降水阈值,统计出了不同台站近46a逐年汛期极端降水量,并进行时空分布特征分析。结果表明:重庆地区汛期极端降水量空间分布差异明显,一致性异常分布特征是最主要空间模态,空间分布可分为5个主要区域;各区代表站汛期极端降水量占总降水量的比重相当大;从长期变化趋势来看,整个重庆地区近46a来汛期极端降水变化趋势不显著;各区汛期极端降水主要存在着2~3a、5a左右的年际变化和11a左右的年代际振荡。

Anomaly Characteristics of Extreme Precipitation over Chongqing in Flood Season during 1961-2006

Based on 1961-2006 daily precipitation data during flood season(from May to September) of 33 stations in Chongqing,by defining the extreme rainfall threshold,study is performed of the annual gross precipitation and the temporal/spatial distribution features of each station in the study period,results show that in flood season Chongqing has the significant spatial distribution differences in extreme rainfall,and the consistently abnormal characteristic is the main spatial mode;Chongqing can be divided into five regions;and the extreme rainfall covers a very large proportion of the total rainfall in each region;and from a long-term trend,the precipitation in Chongqing area does not show significant increasing or decreasing trend,and for the recent 46 years the periodic oscillations of extreme precipitation are dominated by 2-3-year,5-year periods,and about 11-year period.