The spatial distribution and temporal variation of rainfall erosivity in the Yunnan Plateau, Southwest China: 1960-2012

The Yunnan Plateau (YP), southwest China, is a typical plateau mountain region characterized by a monsoon climate. Soil erosion in the YP is recognized as a major environmental problem. Rainfall is abundant in the YP but distributed unevenly on a spatiotemporal scale. However, little published work is available on rainfall erosivity (R factor) in the YP, an important basic parameter for representing the potential ability of precipitation and runoff to erode soil in the Universal Soil Loss Equation. This study integrates the trend coefficient and climate tendency rate indicators and Mann-Kendall nonparametric statistical test to identify the spatial distribution and temporal variation of the R factor in the YP. The daily rainfall records from 1960 to 2012 in the YP were collected from 115 national meteorological observatory stations. The result shows that the average annual R factor was 4382.65 MJ. mm . ha(-1). h(-1) in the YP, and >80% of the annual R was concentrated in the summer and autumn. The spatial distribution of annual, summer and autumn R was greater in the south than in the north while the northwest surpassed other regions for winter and spring R factor. There was significant variability in temporal trends from station to station, in general, the annual and autumn R showed a distribution pattern of an increase in the western YP and a reduction in the eastern YP. The temporal variance of winter R showed a pattern opposite of that of annual and autumn R, indicating an increase in the eastern YP and a reduction in the western YP over recent decades. (C) 2016 Elsevier B.V. All rights reserved.