基于ERA5再分析数据的伊犁河流域干旱灾害风险评估与区划

Risk Assessment and Regionalization of Drought Disaster in Yili River Basin Based on ERA5 Reanalysis Data

依据ERA5再分析数据的分布特点,以0.25°×0.25°的网格为旱灾风险评估的基本单元,从危险性、脆弱性、易损性和防灾减灾能力4个方面选取12个指标,采用AHP-熵值法确定指标权重,对基础数据资料匮乏的伊犁河流域构建干旱灾害风险指数模型,进行干旱灾害风险评估与区划。结果表明,分时段校正后的ERA5再分析降水数据精度显著提高,可用于干旱灾害风险评估;次高、高危险性区域主要分布在研究区西北部和东北部,次高、高脆弱性区域主要分布在海拔较高的山区,次高、高易损性区域主要分布在伊宁市及周边地区,次高、高防灾减灾能力主要分布在研究区西北部,分别占研究区总面积的33.45%、31.04%、16.13%、15.09%;旱灾风险区划图显示,低、次低风险区主要分布在研究区西南部,次高、高风险区主要分布在研究区西北部,分别占研究区总面积的44.69%、22.53%。

According to the distribution characteristics of ERA5 reanalysis data,a grid of 0.25°×0.25°was used as the basic unit for drought risk assessment.12 indicators were selected from four aspects of risk,fragility,vulnerability and disaster prevention and reduction ability,and the weights of the indicators were determined by AHP-entropy method.The drought disaster risk index model was constructed in the Yili River basin where basic data were scarce,and the drought disaster risk assessment and regionalization were carried out.The conclusions are as follows:1)The accuracy of ERA5 reanalysis precipitation data after time-segment correction is significantly improved,which can be used for drought disaster risk assessment.2)The second-highest and high-risk areas are mainly distributed in the northwest and northeast of the study area,the second-highest and high-vulnerability areas are mainly distributed in the mountainous areas at higher altitudes,the second-highest and high-vulnerability areas are mainly distributed in Yining City and its surrounding areas,and the second-highest and high-risk disaster prevention and mitigation capabilities are mainly distributed in the northwest of the study area,where accounted for 33.45%,31.04%,16.13%and 15.09%of the total area of the study area.3)The drought risk zoning map shows that the low and secondary low risk areas are mainly distributed in the southwest of the study area,while the secondary high and high risk areas are mainly distributed in the northwest of the study area,where accounted for 44.69%and 22.53%of the total area of the study area.