Spatial Identification and Risk Assessment of High-Temperature Heat Wave Disasters in Mountain Cities: A Case Study of Chongqing

: [Objective] This research focuses on addressing the increasingly severe issue of extreme urban heat, driven by climate change, both globally and within China. Recent temperature records highlight the urgent need to understand and mitigate impacts of heat waves. The Synthesis Report of the Sixth Assessment Report declares a red warning against global climate change, signifying the most perilous stage of climate change, with 18 out of 31 “planetary vital signs” surpassing historical records. The increase in global temperature in the last 50 years has exceeded the total increase over the previous 2,000 years, making the last seven years the hottest on record. While international efforts have initiated risk assessments for heat waves, previous research in China primarily focuses on spatiotemporal analyses based on meteorological data. Recent research has integrated multiple data sources and socio-economic indicators. However, most assessments are conducted regionally, neglecting intricate risk features within urban areas and precise resource allocation guidance. Moreover, research at the county level in China mainly centers on eastern plain cities, overlooking the unique challenges faced by southwestern mountain cities, known for their complex topography and ecosystems, resulting in higher heat wave risks. Chongqing, situated in the upper Yangtze River region, is a typical mountain city notorious for heat waves. [Methods] To establish a comprehensive risk assessment system for heat waves in mountain cities, this research employs a risk index model. The approach includes the following steps: Firstly, analyze the fundamental causes of heat wave disasters to understand their mechanisms; secondly, identify risk elements of heat waves, and define and quantify assessment factors to construct integrated assessment indicators; lastly, quantify heat wave risks using a quantitative method to establish a comprehensive risk assessment system for mountainous urban areas. This assessment system is based on the disaster risk assessment framework from the Synthesis Report of the Fifth Assessment Report , which additionally incorporate factors