Using ENVI-met simulation to analyze heat island intensity in megalopolises

Abstract

Introduction. The simulation of urban microclimates, including the urban heat island (UHI) phenomenon, has turned all the more important for urban planning. Presently, the analysis of this phenomenon is feasible thanks to high computational power of computers and links between computer modeling instruments and databases that contain information on urban environments. Advanced hardware helps to study characteristics of urban microclimates by analyzing and assessing their exposure to various climatic and anthropogenic urban factors (urban morphology, land use, construction sites, albedo, etc.) Materials and methods. ENVI-met is a software model used to simulate microclimates in urban environments. This software can optimize proportions of buildings and streets, outdoor shading, outdoor space planning, air movement, and use of construction materials in respect of thermal comfort and measures taken to mitigate consequences of urban heat islands within the framework of environmental planning of new districts. The co-authors analyze Ha Dong, a Hanoi district characterized by the high density of high-rise buildings. The co-authors consider the example of this district to study the process of detailed simulation, analysis and assessment of UHI effects. Results. ENVI-met and its simulation capacity is employed to prove that the air temperature in Wang Fu, an urban area, gradually rises from 8 am to 5 pm, when the air temperature reaches its maximal value of 32.28 °C during the period of sixteen hours. UHI intensity was maximal between midnight and 1 am on May 29, 2017, when it reached 2.41 °C. Conclusions. Cities are complex systems exposed to a wide array of interactive factors that influence the urban climate change. The value of R2 equal to 0.94 has proven the reliability of ENVI-met applied to simulate and imitate the climate of Hanoi, which is a hot and damp tropical city.