基于GIS的干旱灾害风险评估及区划研究:以长三角地区为例

Study on Risk Assessment and Zoning of Drought Disaster Based on GIS: A Case Study of Yangtze River Delta

基于全国第一次自然灾害风险普查的开展,干旱是世界上具有严重危害的灾害之一,持续的时间、造成的经济损失、影响的范围,均居于各种自然灾害之首。在全球气候变暖的情况下,干旱灾害发生的频率越来越高,破坏力越来越大。本文从自然灾害风险评估角度出发,利用长三角地区1961~2020年的年降水资料、长三角地区的社会属性资料和地理信息数据,以及GIS技术,从干旱灾害致灾因子危险性、孕灾环境敏感性、承灾体易损失性、防灾减灾能力4个影响指标中选取相对应的评价指标构建了长三角地区干旱灾害风险评估模型,通过所收集的年降水量数据以及温度数据,利用标准化降水指数结合干旱资料选取长三角地区轻旱、中旱、重旱以及特旱发生的频率作为致灾因子危险性评估的指标因子进行研究;对于孕灾环境敏感性的评估,选取降水距平百分率以及植被覆盖度作为评估因子进行研究;对于承灾体易损失性,选取经济密度、人口密度进行评估研究;对防灾减灾能力选取财政收入以及水利设施数作为评估指标进行研究,并对干旱灾害风险进行评估,最后结合自然灾害风险区划原则,对长三角地区干旱灾害进行风险区划。结果表明,江苏省南京市、镇江市、常州市、苏州市、南通市、盐城市、徐州市和浙江省杭州市、舟山市以及上海市闵行区、浦东新区等区域属于高风险区,其他地区干旱风险较低。

Based on the development of the first national natural disaster risk survey, drought disasters is one of the disasters with serious harm in the world, and its duration, economic losses and impact range rank first among all kinds of natural disasters. In the case of global warming, the frequency of drought disasters is getting higher and higher, and the destructive power is getting bigger and bigger. From the perspective of natural disaster risk assessment, this paper uses the annual precipitation data, social attribute data and geographic information data of the Yangtze River Delta from 1961 to 2020, and uses GIS technology to select the corresponding evaluation indicators from four influencing indicators: the risk of disaster-causing factors, the sensitivity of pregnant environment, the vulnerability of disaster-bearing bodies and the ability of disaster prevention and mitigation, and constructs a drought disaster risk assessment model in the Yangtze River Delta. Based on the collected annual precipitation data and temperature data, the frequency of light drought, moderate drought, severe drought and extreme drought in the Yangtze River Delta region is selected as the index factor for risk assessment of disaster-causing fac-tors by using standardized precipitation index combined with drought data. For the assessment of environmental sensitivity of pregnancy disaster, the percentage of precipitation anomaly and vegetation coverage are selected as evaluation factors. For the vulnerability of disaster-bearing bodies, economic density and population density are selected to evaluate and study;the fiscal revenue and the number of water conservancy facilities are selected as evaluation indexes for disaster prevention and mitigation, and the risk of drought disaster is evaluated. Finally, com-bined with the principle of natural disaster risk zoning, the risk zoning of drought disaster in the Yangtze River Delta region is carried out. The results show that Nanjing, Zhenjiang, Changzhou, Suzhou, Nantong, Yancheng and Xuzhou in Jiangsu Province, Hangzhou and Zhoushan in Zhejiang Province, Minhang District and Pudong New Area in Shanghai belong to high-risk areas, while the drought risk in other areas is low.