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中国西北干旱半干旱地区，绝大部分面积年降水量在５００ｍｍ以下，沙漠地带为１００～３００ｍｍ，但季节集中性很强。７、８两个月的暴雨，历时短，强度大，１２ｈ以内的暴雨强度居全国前列，有的位于世界短历时暴雨的外包线附近。由此形成的突发性洪水，破坏力很大，水土流失严重。本地区的产汇流机制比较复杂，在产流分析中，应特别注意雨强因素的影响，作者提出的一种分析方法，在西北地区获得了广泛的应用。设计洪水过程线主要采用瞬时单位线方法，也需要着重考虑在雨强影响下，向设计条件外延的问题。对短缺水文资料的较小流域，主要采用地区综合方法。
In the arid and semi-arid regions of northwestern China, the annual precipitation in the vast majority of areas is below 500 mm and in the desert areas is between 100 and 300 mm, but the seasons are highly concentrated. 7,8 Two months of heavy rain, lasted a short time, intensity, within 12h of the storm intensity ranks the forefront of the country, and some are located in the vicinity of the world’s short-term heavy rain outside the envelope. The sudden floods thus formed have great destructive power and soil erosion are serious. The production and sink mechanism in this area is rather complicated. In the runoff analysis, special attention should be paid to the influence of rainfall intensity factors. An analysis method proposed by the author has been widely used in the northwest region. The design flood process line mainly uses the instantaneous unit line method, but also needs to consider emphatically the problem of extending to the design condition under the influence of the rain intensity. For smaller basins that lack hydrological data, a predominantly regional approach is used.