Influence of Leaf Area Index on the Heat Index of a Tropic Urban Park

Jonathan Willian Zangeski Novais,Thiago Fernandes,Danielle Da Silva Batista,Roberta Daniela De Souza,Renata Luisa Ferreira,Carlo Ralph De Musis

doi:10.34257/gjhssbvol21is3pg67

Abstract

In the wake of climate change, cities need to adapt to global warming. In this context, the use of afforestation to improve the microclimate may assist in raising the quality of life for population. This objective requires research that analyzes how the variations in parameters related to canopy dynamics, such as the leaf area index (LAI) and photosynthetically active radiation (PAR) can influence thermal comfort indices. To contribute to this research, this study measured the air temperature, relative air humidity, PAR, and LAI on a monthly basis from July, 2017, to June, 2018, in an urban park in a tropical region of Brazil. Kriging maps were created for the heat index (HI), and multiple polynomial regression models were adjusted to estimate the HI using PAR and LAI data. After defining the models, positive and negative variations of LAI were tested to observe if any changes in HI occurred. The simulated results showed greater sensitivity to negative variations in LAI, in which a 50% reduction in LAI decreased the HI by 28%, particularly during the dry period.

Highlights

Climate change and its impacts associated with anthropogenic actions including vegetation suppression, land use, and occupation, and the dense and compact set of constructions from constant urban expansion have become the focus of widespread discussion amongst the scientific community (Grimmond et al, 2009; Middel et al, 2014; Petralli et al, 2014)
Results a) Hourly and Seasonal Analyses Hourly averages were determined for air temperature, relative humidity, and heat index (HI) data for mobile transects
The wet season is the period has the highest incidence of solar radiation, as it is summer in the Southern Hemisphere; this equates to higher temperatures and relative humidity

Summary

Introduction

Climate change and its impacts associated with anthropogenic actions including vegetation suppression, land use, and occupation, and the dense and compact set of constructions from constant urban expansion have become the focus of widespread discussion amongst the scientific community (Grimmond et al, 2009; Middel et al, 2014; Petralli et al, 2014). This is due to the changes in the thermodynamic field caused by the decrease in shortwave reflection and increased emission of long waves; this causes an increase in air temperature even during the periods of shorter heat stroke duration, quality of life in cities and the health of the population has fostered the use of research and different methodologies, to demonstrate the effective action of vegetation on the urban microclimate (BuenoBartholomei, 2003; Abreu and Labaki, 2008; Monteiro and Alluci, 2008). Nóbrega and Verçosa (2011) applied the HI in Recife, a seaside town with an Am climate according to the Koppen classification. Silva and Streck (2014) applied the HI to the Cfa climate in Santa Maria, a southern Brazilian city. Souza et al (2020) applied the HI to an Aw climate classification to Cuiabá City, a midwest city in Brazil

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