考虑时间变化的洪涝灾害损失评估

洪涝灾害是对我国影响最大的自然灾害之一。聚焦灾害损失评估问题，本文构建了考虑时间变化的洪涝灾害损失函数。一方面，表征灾害损失随着致灾因子强度先递增、而后增幅趋缓的静态S型曲线关系；另一方面，通过量级、形状和位置三个参数综合考虑灾害损失随时间的动态变化情况。基于《中国水旱灾害防御公报》提供的受灾人口、直接经济损失数据，对于各省级行政区2006—2021年洪涝灾害损失进行评估分析。结果表明：通过拟合洪涝灾害损失函数，洪涝灾害损失关于致灾因子强度和时间的三维空间散点图可有效地拓展成为连续的三维空间曲面及二维空间热力图。各省级行政区受灾人口整体上呈现出逐年下降的特征，但随致灾因子强度的增加而趋于增加。各省级行政区直接经济损失则表现出明显的差异，随时间呈现出大幅下降、缓慢下降和略有增加等不同特征。考虑时间变化的洪涝灾害损失函数是变化环境下灾害评估的有效工具，可为区域洪涝灾情评估提供借鉴和参考。

Incorporating temporal changes into flood loss assessments

Floods are one of the most extensive natural disasters in China.Focusing on the assessments of socioeconomic losses, this paper constructs flood loss functions by introducing a time term to consider temporal change.On the one hand, the functions account for the static S-shaped curve relationship in which disaster losses increase increasingly and then gradually with the intensity of disaster-causing factors;on the other hand, the functions take dynamic changes of disaster losses over time into consideration by the three parameters of magnitude, shape and location.Based on the data set of flood-affected population and direct economic loss provided by the "China Flood and Drought Disaster Prevention Bulletin", assessments of flood disaster losses are conducted for each provincial administrative region from 2006 to 2021.The results show that by fitting the flood loss functions, the scatter plots of flood loss with respect to disaster factor intensity and time can be effectively expanded into continuous three-dimensional surfaces and two-dimensional heat maps.The flood-affected population in various provincial administrative regions generally shows a trend of decreasing year by year and tends to increase with the increase of the intensity of disaster-causing factors.The direct economic losses of various provincial-level administrative regions show considerable differences, with characteristics such as sharp decline, slow decline and slight increase over time.The flood loss functions considering temporal changes can serve as an effective tool for disaster assessment under changing environments, and provides reference for regional flood disaster assessments.