| Spatiotemporal variation characteristics of precipitation during nearly 60 years over Yanwachuan watershed in the tableland gully region of the Loess Plateau |
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| DOI：10.7606/j.issn.1000-7601.2013.05.006 |
| Key Words: precipitation spatiotemporal variation Yanwachuan watershed gully area of the Loess Plateau |
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| Abstract: |
| Spatiotemporal variation characteristics of precipitation in nearly 60 years from 1951 to 2009 were analyzed for the Yanwachuan watershed of the Loess Plateau by the climate tendency rate, wavelet and Mann-Kendall abrupt change test analysis method. Temporally, annual precipitation over th
e watershed presented a declined trend in a fluctuating way, with precipitation in spring and autumn tending to decrease obviously and precipitation in summer and winter increasing slowly. Annual precipitation had a significant oscillation period of 32 years and three alternative cycles of high low high precipitation. Periodic change in summer and autumn influenced annual precipitation more remarkably. Annual precipitation and the maximum daily precipitation with 50 year return period for the watershed were 815.3 and 111.5 mm, respectively. Precipitation in a year mostly occurred from June to September, and the proportion is 68%. Annual precipitation did not show an obviously abrupt change, but two transitions in precipitation were observed in the 1950s and seven transitions in the late 1980s. Spatially, annual precipitation over the watershed during the 60 years showed the distribution that was high in the west and low in the east, of which annual precipitation in the northeast declined more than that in the west. |
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