【摘要】 针对以增暖为主要标志的全球变化导致气候变率增大,极端天气气候事件和灾害发生更为频繁,造成人口、农业经济生产、基础设施风险扩大的现实,以2013年造成延安多地严重受灾极端降雨特性及其对梯田侵蚀影响严重为例,基于延安站多年逐日降雨资料和梯田侵蚀实地测量资料,分析了该极端降雨的特征并探讨了其对梯田侵蚀灾害的影响。结果表明:(1)延安2013年降雨总量达到959mm,比1951—2012多年平均降雨量高出448.8mm,其中7—9月降雨量达到761mm,占全年降雨量的79.4%,最大月降雨7月为568mm,达到万年一遇标准;(2)延安2013年极端降雨侵蚀性降雨和暴雨次数多,暴雨总量大,同时降雨出现短历时中强度、中历时高强度、长历时强侵蚀弱输沙的新变化;(3)延安2013年极端降雨下连片梯田侵蚀剧烈,侵蚀模数和相对高差与汇水面积之间存在显著关系,梯田中下部侵蚀严重,最大土壤侵蚀模数达到54 049.50t/km2,该研究可为水土保持农业梯田工程设计提供依据,同时将为气候变化条件下有效应对该类极端降雨采取永久措施和临时措施及适应性调控提供科技支撑。更多还原

【Abstract】 In view of the fact that the global change which was mainly marked by warming resulted in that the climate change rate increased,the extreme weather and climate events and disasters were more frequent,and the risk of population,agricultural economic production and infrastructure were enlarged.A case on the characteristics of extreme rainfall in Yan’an of 2013 and its severe erosion on the terraces was analyzed which was based on years of daily rainfall data of Yan’an station and terraces erosion field measuring data.The results were showed as bellows:(1)The total extreme rainfall of Yan’an in 2013 reached 959mm,448.8mm higher than the mean annual rainfall(1951—2012).Rainfall from July to September reached 761 mm,which accounted for 79.4 % of the whole year and among which the maximum monthly rainfall happened in July(568mm),reaching the standard of million years;(2)The number of erosive rainfall and rainstorm was much more than before and the total amount of rainstorm was large.Meanwhile,the extreme rainfall showed new changes of short duration and moderate intensity,moderate duration and high intensity,long duration,strong erosion and weak sediment transport;(3)The contiguous terraces were eroded seriously in the extreme rainfall.The soil erosion modulus of terrace had significant correlations with relative elevation and catchment area.The erosion of the moderate and lower terraces was serious and the maximum soil erosionmodulus reached 54 049.50t/km2.This study would provide the basis for the design of agricultural soil and water conservation terrace engineering,and also provide support to take permanent and temporary measures to prevent the extreme rainfall under climate change conditions.更多还原