红壤坡地侵蚀性降雨及降雨动能分析

Analysis of the Erosive Rainfall and Rainfall Erosion Energy on Red-soil Slopeland

侵蚀性降雨标准的确定、降雨动能的科学测算以及侵蚀性降雨和降雨动能特征的分析,是开展降雨侵蚀力研究和土壤侵蚀预测预报的基础,而目前针对红壤坡地的系统研究还较为鲜见。通过气象观测站与标准径流小区连续5 a的实测资料,采用80%经验频率法确定了江西红壤坡地侵蚀性降雨标准,其中雨量标准为9.97 mm,雨强标准为0.756 mm/h;在此基础上计算了侵蚀性降雨和侵蚀性降雨动能,并分析了侵蚀性降雨及其动能的时间变异规律。结果表明:侵蚀性降雨场次不多,仅占总降雨场次的25.85%,但雨量大强度高;侵蚀性降雨及其动能时间分配不均,主要集中在4-9月,分别占全年的74.51%和75.37%。最后建立了降雨动能简易估算方法,这对探讨江西红壤坡地降雨侵蚀力和土壤侵蚀预报模型具有积极的意义。

Establishing rainfall standard of soil erosion, calculating rainfall erosion energy and analyzing their characteristics are important to the studies on rainfall erosivity and erosion prediction. However, these studies on red-soil slopeland are comparable less. By analyzing experiment data through the climate observation station and the bareness runoff plot during 5 years, the erosive rainfall standard on red-soil slopeland in Jiangxi province is established, and that is 9.97 mm and 0. 756 mm/h. Then, the erosive rainfall and its energy are calculated and their distribution regulars in time are studied. It is shown that the number of erosive rainfall is only 25.82 percent during experimental period, but precipitation and rainfall intensity are higher. The erosive rainfall and rainfall erosion energy are variety in yearly, seasonal and monthly distribution, and all mainly distributes between April and September, accounting for 74.51% and 75. 37% respectively among one year. Last, the equation of rainfall erosion energy and precipitation was induced for estimating evalues. This study is important to research the rainfall erosivity and establish soil loss equation in this region.