基于日降雨的沂蒙山区降雨侵蚀力时空变化研究

降雨侵蚀力是水土流失最为重要的外部驱动力,是土壤侵蚀相关领域的研究重点。以沂蒙山区及周边38个气象台站1971—2008年逐日降雨量资料为数据源,利用基于日降雨信息的月降雨侵蚀力模型,估算了研究区多年月、年降雨侵蚀力,并初步分析了降雨侵蚀力的时空分布规律。结果表明:沂蒙山区降雨侵蚀力总体趋势为西北、中南高,北部低,泗水县、曲阜市东部一带是研究区降雨侵蚀力的高值中心;R值与年降雨量和年侵蚀性降雨量的年际变化趋势基本一致,但也有部分异常年份;沂蒙山区降雨侵蚀力年内主要集中分布在6—9月份,占全年的97.07%,其中最大月降雨侵蚀力出现在7月份,占年降雨侵蚀力的51%。研究结果可为该区域水土流失预报、农业面源污染状况预报等提供理论依据。

Spatiotemporal Variation of Rrainfall Erosivity in Yimeng Mountainous Area Based on Daily Rainfall

Rainfall erosivity is the most important external driving force of soil and water loss,and it is the key field of the soil erosion.In order to estimate rainfall erosivity accurately and analyze the spatial distribution and temporal change of rainfall erosivity,a monthly rainfall erosivity model was adopted to calculate the rainfall erosivity in Yimeng mountainous area by using daily rainfall data from 38 stations during 1971—2008.The results show that the spatial distribution of R value in Yimeng mountainous area is higher in the northwest and south central,but lower in north.Sishui County and east area of Qufu City is the high value in the study area.The interannual variability trend of R value is the same as the trend annual rainfall and aggressive rainfall,but there are also some abnormal years.Rainfall erosivity in Yimeng mountain area is distributed mainly from June to September,accounting for 97.07% of all year.The highest R value appears in July,accounting for 51% of the annual rainfall erosivity.The result could provide theoretical basis for forecast of the soil and water loss and agricultural non-point source pollution condition.