Abstract:

The relationship between the summer extreme precipitation in the north and south of the Qinling Mountains and the western pacific subtropical high was analyzed based on the daily precipitation data from 47 stations in the north and south of the Qinling Mountains and the data of area, intensity, west ridge point and ridge line index of western pacific subtropical high from 1960 to 2016. The results showed that: ①On the whole, the extreme precipitation indices were positively correlated with the area and intensity of western pacific subtropical high; they were negatively correlated with the west ridge point, but some abnormal years and negatively-correlated years appeared. The positive and negative correlations between the extreme precipitation indices and the ridge line occurred alternatively. Decadal analysis and M-K test revealed that a mutation increase of the western subtropical high indices and the extreme precipitation indices occurred in the 1980s; ②After the north and south of the Qinling Mountains were divided into four regions, no matter temporally or spatially, drought occurred in the regions to the north and to the south of the Qinling Mountains and the central Hanshui River Basin, but the frequency of extreme precipitation increased in the east and west parts of the Hanshui River Basin and the Bawu Valley when the area and intensity indices were larger, the ridge line index was more southward, and the west ridge point index was more westward. On the contrary, it was opposite. Such extreme precipitation patterns should be the result of response of the Qinling Mountains to the subtropical high; ③The increase of summer extreme precipitation in the north and south of the Qinling Mountains in some years was related to the higher area index, intensity index, southward ridge line and westward ridge point. On the contrary, it was opposite. The westward pacific subtropical high may be one of the important reasons for the increase of extreme precipitation in the north and south of the Qinling Mountains.

Key words: summer')">

summer, extreme precipitation, western pacific subtropical high index, north and south of the Qinling Mountains