陕西省黄土高原地区侵蚀性降水变化特征

利用陕西省黄土高原地区42个站点的逐日降水观测资料,分析了1961-2007年该地区的年降水量、侵蚀性降水量、暴雨量的变化趋势和空间分布特征.研究表明,陕西省黄土高原地区年降水量、侵蚀性降水和暴雨的空间分布非常相似,具有北少南多的分布特征.1961-2007年陕西省黄土高原年降水和侵蚀性降水呈下降趋势,暴雨呈上升趋势.在空间分布上,延安市以北地区,降水量减少幅度小,延安市以南地区降水量减少明显;渭北地区暴雨量增加,而丘陵沟壑区暴雨量则呈减少趋势.

Variation Characteristics of Erosive Rainfall on the Loess Plateau of Shaanxi Province

The variation trends and spatial characteristics of annual precipitation,erosive precipitation,and rainstorm amount from 1961 to 2007 are analyzed using the data of daily precipitation observed from 24 stations on the Loess Plateau of Shaanxi Province. Results show that the spatial distributions of annual precipitation,erosive precipitation,and rainstorm amount are quite similar. The spatial distributions are characterized by greater magnitude in the north than in the south. The annual precipitation and erosive precipitation present a downward trend,whereas rainstorm amount has a rising trend. For the spatial distribution,precipitation is reduced little in the north of Yan'an City,but significantly in the south. The rainstorm amount is increased in the North Weihe Area,but decreased in the hilly and gully region.