陇南山区农业低温冻害气候特征及灾害风险区划

从陇南市1971—2010年低温冻害资料分析得出,陇南山区农业低温冻害主要集中在春季3—5月和秋季9—11月,一般春季低温冻害发生频率较秋季多,农业灾损严重。结合人口、GDP、耕地比等资料,利用ArcGIS软件,得到低温冻害灾害危险性图层,再与承灾体易损性评价及灾害的孕灾背景进行叠加、合并以及等级划分操作,最后得到低温冻害灾害的风险评估及其区划。结果表明,陇南市的低温冻害危险性等级由高到低,自北向南,自西向东递减,宕昌、武都及文县海拔1 800 m以上的高半山区低温冻害危险性等级较高,徽成盆地及武都、文县海拔1 200 m以下的浅山区低温冻害危险性等级较低。低温冻害风险由高到低、自北向南、自西向东递减,宕昌和礼县西北部、武都西北部、文县西南和西北部高海拔区为低温冻害高风险区;康县、两当、成县、徽县以及武都、文县海拔1 200 m以下区域为低温冻害低风险区。

The Climatic Characteristics and Risk Zoning of Frozen Injury on Agriculture in Longnan Hilly Area

This paper analyzes the data of frozen injury on agriculture from 1971 to 2010 in Longnan,and the conclusion is as follows: frozen injury mainly occured during the spring from March to May and autumn from September to November.Generally,the agricultural loss was serious in spring,when the frequency of frozen injury was higher than in autumn.Combined with data about population,farmland ratio,GDP of Longnan city,etc,and utilizing ARCGIS software,the maps of the possibility of disasters were gained.Then,by overlaying and uniting of the background of weather disasters,the vulnerability of stricken things and compartmentalizing the hazard grade,the hazard attributions for frozen injury were achieved.From the map,it is concluded that: the risk grade gradually reduces in area from high to low altitude,from north to south and from west to east.That suggests,the risk grade of frozen injury is the highest in Tanchang,Wudu and Wen counyies over 1 800 meters above sea level,and the lowest risk grade in Huicheng Basin,Wudu,Wen counties below 1 200 meters.The frozen injury risk reduces from the area at high altitude to the area at low altitude,also from north to south and from west to east,so it is high risk area in Tanchang,the northwest of Li county and Wudu,the high altitudes of the southwest and northwest of Wen county,but low risk area in Kang,Liangdang,Cheng,Hui counties and below 1 200 meters above sea level in Wudu and Wen counties.