Analysis on Characteristics of Drought Climate Change in Southwest China in 2006

The most parts of the east of southwest China had suffered the most serious drought since meteorological data had been recorded in 2006. The wider range drought had lasted for a long time and brought severe economic losses in this area. This paper was to analyze changes and distribution of temperature and precipitation in southwest China in 2006. By using daily temperature and precipitation data from 80 observation stations in southwest China covering Chongqing, Sichuan, Guizhou and Yunnan from 1997 to 2006. The monthly average of temperature and precipitation were calculated by mathematical statistical methods and thematic maps were made by the software named ArcGIS 9.3. The characteristic of Climate Change was analyzed for the southwest drought. The result showed that in 2006 the precipitation was generally low, and the temperature was high and the drought was serious in most of southwest China, especially in Chongqing, from June to August. The highest monthly mean temperature and the lowest monthly mean precipitation had occurred in the central area of Chongqing in 2006. The high temperature had last eighty days and was obviously higher in June than that in other months in Chongqing, Bijie and Sinan in Guizhou province, Suining and Nanchong in Sichuan province, and the central of Chongqing was the highest temperature area. The precipitation was significantly low especially from the mid July to the beginning of September in the east of the study area. The most prominent drought took place in the total Chongqing Nanchong and Suining of Sichuan province. In 2006, snowfall reduced about 20% than that in former years on Tibetan plateau, and this situation went against the warm air from south to the eastern part in southwest China. The subtropical convection obviously activated the location of subtropical anticyclone which was located more northward and westward than that in previous years, and the continental high atmospheric pressure stability controlled the east of Sichuan and Chongqing. The cold air turned weak in North China. These drought factors in southwest China caused the less precipitation and the higher temperature, etc.