长江中下游各省市洪涝灾情时空变化及影响因素

基于SL 579—2012《洪涝灾情评估标准》确定了长江中下游各省市1991—2020年的洪涝灾害等级,并采用Mann-Kendall趋势检验法、R/S分析法和随机森林法对洪涝灾情的时空变化及影响因素进行了分析。结果表明：在时间尺度上,1991—2020年长江中下游各省市洪灾损失率和洪灾等级均呈下降趋势,防洪减灾能力有着显著的提升;在空间尺度上,洪涝灾情呈现明显的中游高、下游低,江南高、江北低的分布特征,中游湖北、湖南和江西洪涝灾害等级突变点均为1998年,下游安徽、江苏和浙江为2007年;洪涝灾害等级与降水呈正相关关系,而与防洪减灾能力、社会经济发展水平和自然资源总体呈负相关关系,湖北、江西、江苏、浙江和上海的洪涝灾害等级主要受降水和防洪减灾能力影响,而湖南和安徽则主要受降水和耕地面积影响。

Spatiotemporal variation of flood distribution and influencing factors in provinces in middle and lower reaches of Yangtze River

The flood grades in provinces in the middle and lower reaches of Yangtze River (MLYR) from 1991 to 2020 are evaluated based on the Chinese Flood Damage Assessment Standard (SL579-2012). The spatiotemporal variation of flood disasters and the influencing factors are analyzed using the Mann-Kendall trend test, R/S method and random forest method. The results showed that, from the temporal perspective, the flood loss rates and flood grades decreased in provinces in the MLYR from 1991 to 2020. The flood control and disaster reduction capacity of the MLYR was significantly improved. From the spatio perspective, the flood disasters in the middle Yangtze River (MYR) were higher than the lower Yangtze River (LYR), and that on the south side of the MLYR were higher than the values on the north side of the MLYR. The mutation points of flood grades in Hubei, Hunan and Jiangxi provinces in the MRY occurred in 1998. The mutation points of flood grades in Anhui, Jiangsu and Zhejiang provinces of the LRY occurred in 2007. The flood grades in the MLYR were positively influenced by precipitation, and negatively influenced by socio-economic, natural resources and disaster prevention and mitigation capabilities. The flood grades in Hubei, Jiangxi, Jiangsu, Zhejiang provinces and Shanghai municipality were mainly affected by precipitation and disaster prevention and mitigation capabilities. The flood grades in Hunan and Anhui provinces were mainly affected by precipitation and cultivated area.