Urban Vegetation and Morphology Parameters Affecting Microclimate and Outdoor Thermal Comfort in Warm Humid Cities – A Review of Research in the Past Decade

Abstract

Urbanization provokes major modifications to the natural landscape. As the urban population reaches 60% of the world's population by 2030, this constant development, neglecting the planning and design of open spaces, negatively affects microclimate. This leads to local climate change, urban heat islands, and outdoor thermal discomfort. This paper is based on the recent studies of urban morphology and vegetation parameters affecting urban microclimate and outdoor thermal comfort in warm, humid cities in the past decade. Results revealed that three factors are of paramount importance and affect the thermal comfort level; urban space morphology, the orientation of elements and spaces, and vegetation. Therefore, Scenario developments for micrometeorological simulations should be processed considering the identified parameters of urban morphology and vegetation which are further categorized as parameters of geometry, density, configuration, and the physical properties of plants. However, the Configuration of urban vegetation that affects the thermal comfort of urban spaces has not received adequate attention in previous research yet. Thus, future research is needed considering the planting patterns, arrangement of various species, and planting orientations with prevailing wind conditions. By the end of this review, a theoretical framework is suggested as an approach to assess the impact of urban vegetation and morphology parameters on outdoor thermal comfort in warm, humid climates. The framework guides further research adopting more specific and comprehensive approaches of urban vegetation configuration with reference to specific urban morphologies to improve the local microclimate of cities, where the space for planting is critical. Keywords: urban vegetation, urban morphology, vegetation configuration, outdoor thermal comfort, warm humid cities, Climate change