基于GIS的青海省雪灾风险评估模型

Risk assessment model of snow disaster in Qinghai Province based on GIS

通过建立雪灾定量化评估模型,提供反映雪灾地理分布特征的风险区划,以实现快速、准确地对区域雪灾进行大范围监测和情景分析。根据青海基础地理信息数据,以县级行政为评价单元,提取了91.7m×91.7m栅格的坡度、坡向、草地类型等孕灾环境参数值,对雪灾形成的潜在地理条件进行分析;以雪灾规模、频率和密度等为致灾体危险性指标;选取人口密度、经济密度、交通密度以及土地资源丰富度等社会经济背景数据为承灾体易损性评价指标。基于ArcGIS平台,应用数学综合评价法建立了基于空间统计分析的青海牧区雪灾定量化综合风险评估模型,在使用相关基础图件和资料基础上,对属性和图形数据库进行操作,分别得到雪灾的孕灾环境敏感性、灾害危险性、承灾体易损性评价图层,再经过图层叠加、斑块合并以及等级划分等操作,最终得到青海省雪灾风险区划图。研究结果可对牧区越冬前采取有效风险管理以减轻损失,保障草地畜牧业的可持续发展具有重要意义;并且为当地政府及防灾救灾部门制定灾前减灾规划和灾后救助决策提供科学依据,研究方法对于全国其他省区的雪灾风险评估也具有重要参考价值。

The risk zoning of geography distribution based on the establishment of risk assessment model of snow disaster was provided to carry out the evaluation and monitoring of snow disaster rapidly and accurately in large area. According to the basic GIS data of Qinghai Province, the hazards inducing environment background data, such as gradient and slope, vegetation etc. in the grid of 91.7 m×91.7 m were taken to analyze the geographic condition of snow disaster formation based on the basic measure unit of county. The risk indexes of snow disaster scale, frequency and density which will cause the disaster have been collected for statistic analysis. The people density, economy density, traffic density and richness of land source were selected as the factor of vulnerability assessment, which would provide the accurate information to forecasting and discriminating of snow disaster. The ArcGIS software was used to set up the comprehensive quantitative risk assessment model for snow disaster in Qinghai livestock region. The susceptibility of hazard inducing environment, risk hazardous, vulnerability assessment of sustaining hazard body have been gotten by operating the graphic data base. Finally the regional map of risk management of snow disaster in Qinghai Province was obtained through overlay algorithm of hierarchical maps and plaque combination, class hierarchy. The research results can help to take the effective measurement of risk management to reduce the disaster loss before winter, and it is also very important to keep the sustainable livestock development. The research results can also provide scientific basis to work out the pre-disaster planning and disaster relief strategic decision of post-disaster, and also can provide reference value to other province in risk evaluation of snow disaster.