Acta Geographica Sinica ›› 2004, Vol. 59 ›› Issue (3): 375-382.doi: 10.11821/xb200403007

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Climatic Trend of Rainfall over Tibetan Plateau from 1971 to 2000

DU Jun1, MA Yucai2   

  1. 1. Meteorological Bureau of Lhasa, Lhasa 850001, China;
    2. The Climatic Center of Tibet, Lhasa 850000, China
  • Received:2003-08-10 Revised:2003-11-20 Online:2004-05-25 Published:2004-05-25
  • Supported by:

    The Key Project of Science and Technology Bureau of Tibet, No.2002-43

Abstract:

Using the data of monthly rainfall and rainy days from 1971 to 2000 in Tibet, the linear trends of the annual and seasonal rainfall and rainy days are analyzed. The results show that, the annual rainfall trend in most parts of Tibet increased, rainfall trend was 1.4-66.6 mm/10a, and the change trend of rainfall decreased in Ngari district. A decline trend of rainy days (R≥0.1) was found over Ngari and eastern Nyingchi districts, the increase of rainy days was obvious in middle-western Nagqu and northern Qamdo districts. In the 1970s, the precipitation positive anomaly occurred in western Tibet, and negative anomaly in eastern Tibet. The precipitation anomaly is negative in most parts of Tibet in the 1980s. For precipitation anomaly in the 1990s, the positive appeared in eastern Tibet and the negative in western Tibet. It was also found that change trend of mean annual and seasonal rainfall of Tibet increased during the 30 years, and annual rainfall trend indicated an increase of 19.9 mm/10a, especially in the 1990s. After 1992, the rainfall increased during spring and summer.

Key words: Tibetan Plateau, rainfall, rainy days, linear trend