极端高温胁迫下中国城市脆弱性格局与影响因素

以中国280个城市市辖区为研究对象，从暴露度、敏感性、适应能力3个维度构建城市高温脆弱性评价指标体系，利用气象观测数据、人口普查数据、社会经济统计数据等，量化城市高温脆弱性指数，揭示1990、2000和2010年中国城市高温脆弱性格局，并探讨其影响因素。结果显示：1）在时间维度上，1990－2010年中国城市高温暴露度呈升高趋势，敏感性先升高后降低，而适应能力呈缓慢降低趋势；空间维度上，暴露度整体呈南高北低的集聚态势，敏感性与适应能力分布则较分散。2）1990－2000年，中国城市高温脆弱性格局变化较小，2010年中国城市高温暴露度和敏感度均升高，适应能力却有所下降，导致高脆弱性城市数量骤增，分布范围呈由南向北扩大趋势，1990、2000、2010年高脆弱性城市占比依次为24%、28%、62%。3）区域气候条件、自然环境和城市发展水平的差异是影响城市高温脆弱性的重要因素，夏季月平均气温、热岛强度对城市高温脆弱性具有显著正向影响，人均地方财政收入、夏季月平均降水量、第二产业产值占GDP比重、高程、最大风速和人均固定资产投资额对城市高温脆弱性具有显著负向影响。气温对于城市高温脆弱性正向效应远大于城市社会经济条件的负向效应，城市高温脆弱性主要受区域温度环境的影响。

Urban Vulnerability Pattern and Influencing Factors under Extreme Heat Stress in China

With the ongoing global climate change, extreme heat events have a profound negative impact on the socio-economic development of cities. In this study, through a portrayal of the urban vulnerability pattern of cities under extreme heat stress in China, as well as an in-depth analysis of its influencing factors, a foundation was laid targeting reduction in the risk of extreme heat event occurrence in these cities and building a healthy urban environment. Herein, the municipal districts of 280 cities in China were considered as the research targets. On the basis of meteorological observation data, census data, and socio-economic statistics, the urban vulnerability assessment index system for extreme heat was constructed from the standpoint of three dimensions: Exposure, sensitivity, and adaptability. The set pair analysis method and the vulnerability index model method were used to comprehensively calculate the indices of urban exposure, sensitivity, adaptability, and vulnerability to extreme heat. Thereby, the spatial and temporal distribution patterns of urban exposure, sensitivity, adaptability, and vulnerability to extreme heat in the main cities in China for 1990, 2000, and 2010 were revealed, following which the factors affecting the urban vulnerability to extreme heat were discussed. The following conclusions from three standpoints were ultimately drawn. First, from 1990 to 2010, the urban exposure index to extreme heat in China gradually increased, the urban sensitivity index first rose and then declined, and the adaptability index demonstrated a slow decline. The overall spatial distribution of urban exposure to extreme heat is high in the south and low in the north, while the urban sensitivity and adaptability to extreme heat are widely distributed and scattered throughout the country. Second, from 1990 to 2010, the number of cities with a high vulnerability to extreme heat showed an overall trend of increase, accounting for 24%, 28%, and finally 62% of highly vulnerable cities, which implies that the vulnerability to extreme heat in China gradually increased. From 1990 to 2000, the pattern of urban vulnerability to extreme heat in China changed slightly. In 2010, the number of cities with high vulnerability increased sharply, and the distribution range expanded from the south to the north of China. Further, the overall distribution of urban vulnerability to extreme heat was high in the south and low in the north. Third, urban vulnerability to extreme heat is mainly affected by the regional climate conditions, natural environment, and differences in urban development levels. The average monthly temperature in summer and heat island intensity both have a significant positive impact on the urban vulnerability to extreme heat. On the contrary, the per capita local fiscal revenue, average precipitation in summer, output value of the secondary industry as a percentage of GDP, elevation, maximum wind speed, and per capita investment in fixed assets all have a significant negative impact on the urban vulnerability to extreme heat. However, the positive impact of the average monthly temperature in summer on urban vulnerability to extreme heat is far greater than the negative impact of social and economic conditions. Therefore, it can be inferred that urban vulnerability to extreme heat is mainly affected by the regional temperature environment.