Abstract:

Rainfall is the main dynamic element causing soil erosion.The separation of soil is caused by raindrop splashing.Erosion and movement of flowing water eventually lead to soil loss.Eroding force of rainfall is the potential ability of soil erosion.An accurate evaluation of rainfall erosion force can provide an important background parameter for the quantitative evaluation to soil erosion in a certain region.We analyzed the 1957-2008 daily rainfall data of 26 weather stations in and around Hubei, and used the Daily Rainfall Erosion Force Model to calculate annual rainfall erosion force in the study area.Wavelet Analysis and MannKendall Analysis were used to analyze the trend of annual rainfall erosion force and its periodic variation.Then Kriging Interpolation was adopted for spatial interpolation, and for drawing the contour map of rainfall erosion force in Hubei Province.The time change regulation and spatial distribution characteristic of rainfall erosion force have been preliminarily analyzed.The result showed that the general trend of the annual average rainfall erosion force of the whole province presented a decline from southeastern area to northwestern mountain area.This probably has something to do with the high amount, strength of local rainfall and high kinetic energy of raindrops in rainy seasons.The general trend of rainfall in the province presented a decline from southeast to northwest,and it showed higher values in southwest and southeast Hubei,especially the Lvcongpo Station reached 1683.05 mm.The rainfall erosion force of annual variation in Hubei Province generally had the same trend with the change of annual rainfall,but there were also some years (i.e.,1963,1999 and 2003) that presented high annual rainfall while low rainfall erosion force.It showed that there were relatively less erosive rainfalls.On the other side,there were some years (i.e.,1969,1991 and 1998) that presented high rainfall erosion force while low annual rainfall.Based on this trend,both the annual rainfall and rainfall erosion force had a slightly increasing trend.The annual rainfall showed a more obvious increase in rainfall erosion force.The rainfall erosion force in Hubei was concentrated in MaySeptember,which accounted for 7742% of the whole year.The annual distribution of rainfall erosion force in Hubei Province shared almost the same regulation with the rainfall in study area.In MaySeptember,the rainfall erosion force was obviously higher than the related rainfall,and other months were relatively lower.The difference was caused by the rainfall characteristics in different periods.The high amount and strength of local rainfall and its high kinetic energy of raindrops occurred in MaySeptember,however,the phenomenon in JanuaryApril and in OctoberDecember was opposite to MaySeptember.As a result,because of different rainfall intensity and rainfall erosion force,the difference between rainfall erosion force of different month is obvious,and not uniform with the difference in rainfall.The results have an important implication on the forecast of water and soil loss,and measuring water and soil conservation scientifically