粤北岩溶区连江流域降雨侵蚀力

Rainfall Erosivity in the Lianjiang Watershed in Karst Areas of Northern Guangdong, China

对连江流域35个气象站1980―2013年逐日雨量数据进行整理,利用日雨量、月雨量和年雨量方法计算得出RA、RB、RC,通过有效系数M检验得出最优R值;然后利用反距离加权、张力样条函数和普通克里金进行空间插值,通过检验确定最准确的插值方法,最后对其进行插值分析。结果表明:基于月降雨量的计算方法和反距离加权插值法更加适合于连江流域降雨侵蚀力的计算和估算;连江流域降雨侵蚀力时空变化明显,降雨侵蚀力变化与年际降水量变化基本一致;中上游高大山脉存在的地区,多年平均降雨侵蚀力明显高于其他地区;下游多年平均降雨量丰富,其多年平均降雨侵蚀也较严重。

One of the main ecological environment problems is soil erosion for the Lianjiang Watershed. Rainfall erosivity reflects potential ability of soil erosion caused by rainfall. Therefore it is of great significance for valuing consequences of regional soil loss caused by regional rainfall erosivity precisely and formulating measures to maintain soil and water. We arranged the data of daily precipitation from 1980 to 2013 at 35 meteorological stations along the Lianjiang river basin. Based on the data above, we got RA, RB and RC, which were calculated from daily precipitation, monthly precipitation and annually precipitation. We got the optimum R through the test of effective coefficient M accordingly. Next, we used the Inverse Distance Weighted（IDW）, Spline with Tension and Ordinary Kniging for spatial interpolation and test to ensure the most accurate interpolation method, and then made interpolation analysis. The result showed that： the IDW and monthly precipitation was more suitable for the calculation and valuation of rainfall erosivity in the Lianjiang Watershed. The spatial-temporal variation of rainfall erosivity in the Lianjiang Watershed was evident. The spatial distribution of rainfall erosivity was similar to that of precipitation year-by-year. In the middle-upper reaches of the Lianjiang River, the average annual rainfall erosivity was found significantly higher in high and large mountain areas than in other places. There was more plentiful precipitation in the lower reaches of the Lianjiang River, and also the average annual rainfall erosivity in the areas was relatively high.