Abstract:
An objective identification technique for the regional extreme events (OITREE) and the daily composite-drought index (CI) of the 101 stations in southwestern China including Sichuan, Yunnan, Guizhou and Chongqing were used to investigate the southwestern China regional meteorological drought events during 1960-2010. The values of the parameters of the OITREE method were determined. 87 events were identified, including 9 extreme events in which the 2009/2010 severe drought in southwestern China is the most serious meteorological drought event for the past 50 years. Further analysis reveals that: The durations are generally between 10-80 d, with the longest period being 231 d. November to April is the dry season in southwestern China. As far as the regional distribution is concerned, Yunnan and southern Sichuan have the highest drought frequency and intensity, and strong (extreme and severe) southwestern China regional meteorological drought events could be divided into five types, with the Southern type occurring more frequently. During the past 50 years, the southwestern China regional meteorological drought events show a significant increase trend in frequency and an obvious increase trend in intensity, for which the main reason may be the significant decrease of the annual precipitation in this region, with a contribution by the significant increase trend in temperature.