Measuring and modelling spatial variation of temperature and thermal comfort in a low-density neighbourhood in Singapore

Abstract

This thesis examines ENVI-met?s applicability in a humid tropical urban environment. Micro- and bio-climatic evaluations are conducted using measured 2-m air temperatures (Ta-2m) and mean radiant temperatures (MRT) at pedestrian height. Results indicate that ENVI-met simulates spatially-averaged Ta-2m better (RMSE: 0.52-0.89?C) during the wetter monsoon seasons, than during the dry Inter-monsoons (RMSE: 1.11-1.41?C). MRT evaluations indicate variable daytime model performance (RMSE: 6.44-14.02?C) where unsystematic errors dominate. The thesis also evaluates how manipulating key urban design variables affects the micro- and bio-climate. These variables are split into three categories: (i) albedo, (ii) vegetation type and cover, and (iii) building heights. Simulations suggest that increasing roof albedo results only in notable local-scale Ta-2m reductions, while increasing wall albedo increases both Ta-2m and MRT. The vegetation scenarios result in significant micro-scale but negligible local-scale thermal comfort changes. Finally, increasing building heights generally improves daytime thermal comfort through increased shading.