干旱区生态环境知识资源中心

This paper adopts the meteorological data from 1951 to 2014 provided by 73 national ordinary stations in Hetao area, China, combines Kendall-tau non-parametric test method and Sen’s slope estimation method based on sub-regions divided by fuzzy clustering method and analyses the variation trend of extreme precipitation indexes in the area. The results show that: (1) In the arid and semi-arid subregion (located in the upper reaches of the Yellow River) and humid and semi-humid sub-region (located in the middle and lower reaches of the Yellow River) in Hetao area, extreme precipitation events have different variation trends, and the spatial distribution of precipitation is unbalanced. (2) Except the precipitation of extreme wet days has significantly increased (R99p is 32.01 mm /10a), other indexes do not increase significantly in the arid and semi-arid sub-region of Hetao area. (3) In the humid and semi-humid sub-region of Hetao area, the variation trends of the other 9 indexes are negative except the indexes consecutive days with rain (CWD) which showed upward trend (0.03d/10a). (4) There is an upward trend of extreme precipitation events in Bayinmaodao, but other regions in Hetao area have not increased.