Exploring the impacts of heat release of vehicles on urban heat mitigation in Sendai, Japan using WRF model integrated with urban LCZ

Abstract

Studies have been conducted globally on urban heat countermeasures utilizing Weather Research and Forecasting (WRF) numerical modeling system. Yet, the effects of vehicle heat (VH) on near-surface air temperature in Japanese cities were not clarified. In this study, the WRF Building Effect Parameterization and Building Energy Model (BEP-BEM) coupled with local climate zones (LCZs) was adopted for simulating the influences of VH on the urban climate over Sendai, Japan. To do so, we proposed a novel method to estimate the hourly VH for LCZs via open-source data. Integrating VH and specific urban canopy parameters (UCPs) into BEP-BEM, the climate model was established and then validated with the observed data. Based on that, effects of various urban heat countermeasures were analyzed at a high spatial resolution. It was found that eliminating the vehicle heat contributes up to 0.12°C to urban heat mitigation, as the most effective countermeasures for the compact areas of city center. This study provided a feasible and reliable workflow to quantitatively evaluate urban heat mitigation strategies at high spatial resolution, specifically for reducing VH in Japanese cities, that can support related urban planners and decision makers for implementing targeted urban heat mitigation strategies.