Acta Geographica Sinica ›› 2011, Vol. 66 ›› Issue (9): 1179-1190.doi: 10.11821/xb201109003

Previous Articles     Next Articles

Climate Characteristics of the Extreme Drought Events in Southwest China during Recent 50 Years

HE Jinyun, ZHANG Mingjun, WANG Peng, WANG Shengjie, WANG Xingmei   

  1. Geography and Environment College of Northwest Normal University, Lanzhou 730070, China
  • Received:2011-04-15 Revised:2011-06-03 Online:2011-09-20 Published:2011-09-20
  • Supported by:

    Program for New Century Excellent Talents in University by the Education Ministry of China, No.NCET-10-0019;National Natural Science Foundation of China, No.41161012; Foundation for Young Innovative Scientists in Gansu Province; Knowledge and Technological Innovation Project of Northwest Normal University, No.NWNU-KJCXGC-03-66

Abstract: Based on the daily data of temperature and precipitation of 108 meteorological stations in Southwest China from 1960 to 2009, we calculated the surface humid indexes of months and years, as well as the extreme drought frequency. According to the data, the temporal and spatial characteristics of the extreme drought frequency in inter-annual, inter-decadal, summer monsoon and winter monsoon has been analyzed. The results are indicated as follows: (1) In general, the southwest of Sichuan Basin, the southern part of Hengduan Mountains, southern coast of Guangxi and north of Guizhou are the areas in which the extreme drought frequency has significantly increased in the past 50 years. For the decadal change, from the 1960s to the 1980s the extreme drought frequency has presented a decreasing trend, and the high frequency area appeared alternately in the southeast - northwest - east of Southwest China; the 1990s is the most wettest decade and it is wet over the whole area. In the 2000s, the extreme drought frequency rises quickly, but the regional differences reduce. (2) In summer monsoon, the extreme drought frequency is growing, which generally happens in the high mountains around the Sichuan Basin, most parts of Guangxi and "the broom-shaped mountains". It is obvious that the altitude has impacts on the extreme drought frequency of summer monsoon; in winter monsoon, the area is relatively wet and the extreme drought frequency is decreasing. (3) In summer monsoon, the abrupt change happened in 2003, while the abrupt change of winter monsoon happened in 1989, and the joint abrupt changes in different periods lead to the extreme drought frequency variation. The departure sequence vibration of annual extreme drought frequency is quasi 5 years and quasi 12 years.

Key words: Southwest China, extreme drought, summer monsoon, winter monsoon, temporal and spatial characteristics