Singapore’s Digital Urban Climate Twin: an analysis of heat mitigation measures from island to neighborhood scale

Abstract

The Urban Heat Island (UHI) effect intensifies thermal stress in cities, impacting population health, energy consumption, and overall liveability. Climate modelling is crucial for assessing and optimizing heat mitigation measures. The complexity of the UHI, however, requires an integrated approach that captures the spatio-temporal complexities of different urban elements, such as land use, buildings, and other anthropogenic heat sources. In this study, we utilize a Digital Urban Climate Twin (DUCT) that incorporates city-specific data within a mesoscale climate model for the city of Singapore, enabling a detailed analysis of how changes to various urban factors influence air temperatures. Specifically, we test three mitigation measures: transitioning fully to electric vehicles (EVs), enhancing building air-conditioning efficiency, and increasing urban vegetation. Results reveal distinct spatial patterns and time-of-day impacts from the three approaches. A 100% adoption of EVs leads to a notable reduction in nighttime air temperatures, with peak cooling effects observed during morning traffic rush hours, especially towards the central business district regions with a high density of traffic networks. Improvements in building air-conditioning efficiency and set-point temperatures show minor nighttime cooling effects but demonstrate a reduction in midday temperatures. Additionally, the study highlights the role of urban vegetation in moderating diurnal surface heat fluxes, underscoring its potential to mitigate urban heat. These comparative studies demonstrate the use of the DUCT as a tool to guide policy implementation through simulations, enabling the development of more targeted heat mitigation strategies across various spatial scales.