关键词: 降水, 大尺度环流, 川西高原

Abstract:

Daily precipitation data of 8 meteorological stations on the west Sichuan plateau from 1960 to 2006 is used to analyze the variation of summer precipitation and its relationship with the large-scale circulation. The results show that: (1) The summer precipitation over the plateau increased weakly from 1960 to 2006. There was more summer precipitation in 1960s , 1980s and the last several years, while there was less summer precipitation in 1970s and 1990s. (2) The large-scale circulation in more precipitation years was quite different from that in less precipitation years. There was continuing block high in Okhotsk and Ural regions in more precipitation years, when the East Asian Trough became stronger, but the South Asian High was weaker, and the updraft over the Tibetan Plateau was stronger. These large-scale circulations are advantageous to the summer precipitation over the plateau. (3) In years with more precipitation, the previous spring OLR showed that the updraft in mid-Indian Ocean enhanced, while that in Indonesia and South Ocean weakened. The previous OLR field may offer some references for predicting the summer precipitation over the west Sichuan plateau.

Key words: precipitation, large-scale circulation, west Sichuan plateau