Spatial and temporal variations of extreme precipitation and temperature events for the Southwest China in 1960–2009

Abstract

Background: Extreme climate events leading to tremendous life and property losses, environmental degradation, have recently received increased attention. It is applied to a data set consisting of 116 weather station records (1960–2009) covering the Southwest China, and measured the spatial and temporal characteristics of precipitation and temperature extreme and their long-term trend have been analyzed, the possible reason for the recent 2009 SWC severe drought is briefly discussed too. Results: The most remarkable result is, compared with the base year, significant decreasing trend has been measured for the precipitation amount and the rainy days while regardless the mean temperature, maximum temperature or minimum temperature is clear warming in 2009 over SWC, particularly in the 9-12 month, less precipitation combined with unreasonable high temperature may be the major contributor to the mega-drought crippling into SWC in 2009-2010. Although no significant trend has been indentified for annual precipitation, great sub-seasonality and regional difference has been detected over SWC. Statistical significant decreasing trend has been examined for rainy days over SWC and the downward prevail in the second half of a year, especially in the autumn month while the first half of a year is characterized by positive trend of maximum precipitation, rainy day intensity and annual precipitation. Maximum temperature and minimum temperature showed significant warming trend in every month, in particular the upward trend of the minimum temperature is stronger than that of the maximum temperature. Conclusions: It is somewhat resulting easily in the increase of frequency of extreme events, that is, increase the frequency of flooding and drought in the Southwest China.