武都山区大到暴雨时空演变气候特征及灾害风险区划

分析了武都山区近40年来暴洪灾害发生变化规律,通过对致灾因子危险性、孕灾环境敏感性、承灾体易损性、防灾减灾能力等多因子综合分析,利用ArcGIS软件得到大到暴雨灾害危险性图层,再同承灾体易损性评价、灾害的孕灾背景进行叠加、合并以及等级划分操作,最后得到大到暴雨灾害的风险评估及其区划。结果表明,武都山区大到暴雨主要出现在5～9月,7～8月是多发时期,60%以上的大到暴雨出现在这一时段,6月和9月次之,5月份大到暴雨出现最少,其他月份尚无出现过暴雨;武都山区大到暴雨主要出现在夏半年,且年际趋势变化不大。武都山区大到暴雨危险性等级南部高于北部、山区高于川区,由西北高海拔区域向西北低海拔区域递减,由南部向北部递减;大到暴雨洪涝风险等级由东南向西北递减。

Space-Time Evolution Characteristics of Rainstorm and Disaster Risk Zoning in Wudu Mountainous Areas

The occurrence laws of rainstorm disasters in Wudu mountainous areas in recent 40 years were analyzed,the risks of disasters-causing factors,the sensitivity of disasters-forming environment,the vulnerability of disasters-affected body,and the capacity of disasters prevention and mitigation were comprehensively studied.The disasters risks map of rainstorms was made with ArcGIS software,and then overlaid,merged and graded with the evaluation of vulnerability of disasters-affected body and the disasters-forming background,and finally the rainstorm disaster risk zoning was concluded.As indicated by the results,the rainstorms in Wudu mountainous areas mainly appear from May to September,especially in July to August,then followed by June and September,the least in May,no rainstorms have appeared in other months.Most of the rainstorms appeared in the second half year without big changes in different years.The risk level of rainstorms was higher in south than in north,and higher in mountainous areas than in hilly regions,it gradually decreased from the high-altitude area to low-altitude area in northeast and from south to north;the floods risks gradually decrease from southeast to northwest.