1960-2009年中国降雨侵蚀力的时空变化趋势

降雨侵蚀力反映了降雨对土壤侵蚀的潜在能力,因此降雨侵蚀力已经成为土壤侵蚀、产沙和水环境建模的主要参数之一。利用中国590个气象站1960-2009年逐日降雨量资料估算了中国每个气象站的降雨侵蚀力,并使用趋势系数、气候倾向率和Kriging空间插值方法分析了中国降雨侵蚀力的时空变化趋势。结果表明:我国年均降雨侵蚀力从东南沿海向西北内陆逐渐递减,与年均降水量空间分布基本一致;近50年来我国大部分地区年降雨侵蚀力呈现不显著的上升趋势,存在四个明显的上升区域和两个明显的下降区域;59个气象站年降雨侵蚀力变化趋势通过了0.05显著水平的置信度检验,年降雨侵蚀力显著增加的气象站主要分布在青藏高原中东部、东缘、天山山脉以及东南沿海区域。青海省的诺木洪-都兰-曲麻莱-伍道梁一带近50年来年降雨侵蚀力增加趋势最为显著,有可能加剧长江、黄河源头土壤侵蚀的风险。

Temporal and spatial variations of rainfall erosivity in China during 1960 to 2009

Soil erosion is one of the most important environmental concerns of China. It is shown that rainfall erosivity is prone to cause severe soil loss, so it is used as a primary input parameter for soil erosion, sediment yield and water quality modelling. Based on the daily rainfall data from 590 meteorological stations in China from 1960 to 2009, rainfall erosivity was estimated and the temporal and spatial distribution was analysed with trend coefficient, climate tendency rate and the ordinary kringing methods with the aid of ArcGIS 9.2 software, respectively. The results show that the spatial distribution of rainfall erosivity has a decreasing trend from the southeast coastal regions to the northwest inland regions. The spatial distribution of average annual rainfall erosivity is similar to that of average annual precipitation. There is a slight increase of annual rainfall erosivity in most parts of China. There are four areas whose annual rainfall erosivity has a significant increasing trend and two areas with a significant decreasing trend in the 50 years. There are 59 stations whose coefficients of tendency pass the confidence test with 5% level of significance, and these stations are mainly located in the eastern and central Qinghai-Tibet Plateau, Tianshan Mountains and the southeast coastal regions. The areas of Numuhong, Dulan, Qumalai and Wudaoliang in Qinghai Province see the most significant increase from 1960 to 2009 throughout China, indicating that soil loss might be aggregated by rainfall increase in the headwaters of the Yangtze River and Yellow River.