Applications of Models and Tools for Mesoscale and Microscale Thermal Analysis in Mid-Latitude Climate Regions—A Review

Abstract

Urban analysis at different spatial scales (micro- and mesoscale) of local climate conditions is required to test typical artificial urban boundaries and related climate hazards such as high temperatures in built environments. The multitude of finishing materials and sheltering objects within built environments produce distinct patterns of different climate conditions, particularly during the daytime. The combination of high temperatures and intense solar radiation strongly perturb the environment by increasing the thermal heat stress at the pedestrian level. Therefore, it is becoming common practice to use numerical models and tools that enable multiple design and planning alternatives to be quantitatively and qualitatively tested to inform urban planners and decision-makers. These models and tools can be used to compare the relationships between the micro-climatic environment, the subjective thermal assessment, and the social behaviour, which can reveal the attractiveness and effectiveness of new urban spaces and lead to more sustainable and liveable public spaces. This review article presents the applications of selected environmental numerical models and tools to predict human thermal stress at the mesoscale (e.g., satellite thermal images and UrbClim) and the microscale (e.g., mobile measurements, ENVI-met, and UrbClim HR) focusing on case study cities in mid-latitude climate regions framed in two European research projects.

Climate Mitigation Strategies: The Use of Cool Pavements

“…The multiplicity of materials inside the built environment produces, particularly during daylight hours, distinct patterns of climatic conditions. Intense solar radiation and high temperatures strongly disrupt the environment, increasing thermal stress at the pedestrian level [99]. Some groups at the University of Padua have, in recent years, analyzed the phenomenon of UHI generation in the Padua area [100], identifying the main factors influencing this process:…”

Cooling Potential of Urban Tree Species during Extreme Heat and Drought: A Thermal Remote Sensing Assessment

“…Untangling these effects is an important research area in urban climatology and could provide improved insights into the impacts of green infrastructure. Additional field surveys and in situ measurements, such as extended measurement networks in different urban neighborhoods or mobile measurements, are important approaches to distinguish between the effects of different imperviousness levels and the effects of trees on T diff [56,98]. High-resolution modeling approaches, such as ENVI-met, UrbClim HR, or PALM-4U [99], which were successfully applied to unravel urban climate mechanisms and influencing factors for urban heat islands in existing research [98,100,101], are another alternative method to augment research on the cooling effect of trees in urban environments.…”

On the Role of Urban Mobility Layout against Urban Microclimate. The Case Study of Turin, Italy

“…The model can simulate microscale interactions between urban surfaces, vegetation, and atmosphere [42]. It could be used to simulate different atmosphere processes such as air flow, air temperature, humidity, turbulence, radiation fluxes and to calculate various thermal comfort indices including physiologically equivalent temperature (PET), the predicted mean vote (PMV), Universal Thermal Comfort Index (UTCI) and others [33]. ENVI-met is one of the most widely used tools for microclimatic research, urban design and thermal comfort studies due to its capacity to recreate microclimatic conditions within urban canopy layer [43][44][45].…”

“…Modelling urban elements and climate at the micro-scale has enabled analysis of the impact of different urban features on climatic conditions for the examination of existing environment, prediction of the microclimate conditions under different planning scenarios and the verification of the effectiveness of the applied strategies and policies. These models have become instruments to facilitate communication between technical and non-technical professionals [33] to support decision and policy making. The most common tools for simulating microclimate processes are Computational Fluid Dynamics (CFD) models, due to their ability to address a wider range of issues including air flow, air quality, pollution and thermal comfort, compared to other numerical tools [34,35].…”