Spatiotemporal characterization of heatwaves on an urban center using satellite-based estimates.

Climate variability, climate change, and anthropogenic disturbances increase the likelihood and intensity of heatwaves. Urban centers, characterized by dense populations, are experiencing a growing impact from these heatwaves. A comprehensive understanding of the spatiotemporal characteristics of heatwaves is essential for proposing effective mitigation strategies. This study utilizes land surface temperature datasets from 2003 to 2020 to characterize spatial and temporal variability of heatwaves across the Kathmandu Valley, Nepal, and identify regions and periods with high heat hazards, exposure, and risks. Regions with high heatwave hazards are identified based on frequency, duration, and magnitude of heatwaves for daytime, nighttime, average of daytime and nighttime, and a combination of both conditions. Additionally, vulnerability is assessed based on demographic distribution. Heatwave Risk Index is computed by superimposing composite heatwave index and vulnerability. Through geospatial analysis, our study identifies distinct regions and time periods characterized by varying levels of heatwave severity and associated risks to diverse population distributions. In recent years, there has been a notable increase in the prevalence of extreme heatwave conditions, particularly after 2010 and especially from 2012 onwards. Importantly, this trend is more pronounced in nighttime temperature data, highlighting discomfort during the night when the body requires rest and recovery. Our findings emphasize the crucial need for policies tailored to urban environments, addressing factors related to the built environment factors, societal stresses, and vulnerabilities. These policies are essential for enhancing systematic preparedness in response to the challenges posed by a changing climate. [ABSTRACT FROM AUTHOR]