Abstract:

Based on survey records of torrential flood disasters from different villages and towns in Wuwei during 1971 －2012 and the
precipitation data from 78 regional weather stations and 4 automatic weather stations from May to September during 2008 －2012 in Wu-
wei，the main disaster － causing factors affecting torrential flood such as critical rainfall，terrain slope，drainage density，precipitation，
rainfall days，moderate rainfall days and heavy rain days during the flood season，were found out via analyzing dynamical conditions，
the environment pregnant with disasters and weather background of torrential flood forming，firstly． Next，on this basis the division
model of torrential flood disaster was established by using the principal components analysis (PCA ) method． Combined the grading
standard of torrential flood disasters，including high disaster － prone area，disaster － prone area，general area and low disaster － prone
area，the preliminary study on division of torrential flood disasters in Wuwei was carried out which supported by GIS technique． The re-
sults show that the influencing degree of factors resulting in torrential flood disaster declined from 10 mm or above rainfall days，topog-
raphy，rainfall days and precipitation in flood season，moderate rain days，24 h critical rainfall and drainage density in turn． The inten-
sity of torrential flood disasters in Wuwei decreased from southwest to northeast． The high disaster － prone area was the Tianzhu county
which was located in southern Wuwei，where the topography was complicated and the strong convective weather occurred frequently．
The Gulang county was in central － south Wuwei and it was the disaster － prone area，while the general disaster － prone area was in Li-
angzhou and Minqin county occurred rarely．

Key words: the division of torrential floods disaster, disaster － causing factors, principal components analysis (PCA), GIS tech-nique, Wuwei

摘要：

应用 1971 ～2012 年武威市各乡镇山洪灾害调查记录，以及武威市内 78 个区域气象站和 4 个自动气象站 2008 ～2012 年 5 ～9 月降水资料，通过对山洪灾害形成的动力条件、孕灾环境、降水背景的分析，确定临界雨量、地形因子、河网密度、汛期雨量、汛期降水日数、汛期中雨日数、汛期大雨日数为影响山洪灾害形成的主要因子，采用主成分分析方法建立武威市山洪灾害区模型。在 ArcGIS 软件的支持下，对各影响因子进行空间插值、栅格图层计算等操作，将武威市分为山洪灾害高发区、易发区、一般区和低发区 4 类，初步探索了武威市山洪灾害分布区划。分析表明，武威市山洪灾害由东南向西北递减，南部天祝县呈高发区，易发区主要在南部古浪县，中部平原凉州区为一般区，北部荒漠带民勤极少能形成山洪灾害，为低发区。

关键词: 山洪灾害, 动力条件, 孕灾环境, GIS, 区划