High-resolution urban temperature simulation method considering various spatiotemporal boundary impacts

Abstract

Climate change has heightened the frequency and intensity of extreme heat events in cities, greatly impacting human health, the environment, and socio-economic activities, particularly in densely populated areas. Canopy temperature (T2m) is a key indicator of whether urban area extreme heat is occurring, with significant implications for public health, energy consumption, and pollution levels. However, the diverse urban topography, functional layout, and human activities contribute to significant variations in the distribution of T2m. While computational fluid dynamics (CFD) models offer high-resolution T2m simulations, complexities in urban spatial and temporal dynamics make accurately defining boundary conditions challenging, potentially leading to large simulation errors. This study addressed the challenge of determining precise boundary conditions for urban CFD simulations by employing the Weather Research and Forecasting model to integrate meteorological reanalysis data. Different meteorological reanalysis datasets used to simulate T2m were compared, including Final Operational Global Analysis, Global Forecast System, and European Centre for Medium-Range Weather Forecasts Reanalysis v5. When combined with the reanalysis data, the minimum mean relative error of simulated T2m was 4%, which is a threefold improvement in accuracy compared to traditional meteorological boundary conditions. This study provides technical support for refined zoning of urban extreme heat risk and urban management in the context of climate change.