Interference of Harvesting on Urban Heat Island Intensity in a Mid-Sized City in Brazil

The classic setup for assessing the Urban Heat Island (UHI), i.e. the relative difference between observed air temperatures in urban spaces and in rural counterparts, can often be quite tricky, considering that in the Anthropocene available rural locations close to the urban fringe can have marked agricultural use. The issue of climate variability of rural areas is a determining factor for assessing UHI intensity. Brazil is the world's largest sugarcane producer, with a 33% share of the global market. Many mid-sized cities in the Brazilian state of São Paulo are located close to sugarcane fields, which all undergo the sugarcane growth cycle with defined pre-harvest and post-harvest stages. The aim of this study is to understand the interference of seasonal harvesting periods in sugarcane plantations on the formation of UHI in and around (at suburban locations) Piracicaba, located in the state of São Paulo, Brazil, at 22º 42' 30" S and 47º 38' 01'' W and characterized by Köppen-Geiger’s Cfa, humid subtropical climate. We deployed a fully-equipped weather station at the site of a sugarcane crop at post- and pre-harvest and a small network of five weather stations with air temperature and humidity sensors downtown and in suburban neighborhoods in Piracicaba. Pre-harvest showed the highest UHI intensities, also confounding the analysis of intra-urban temperature differentiation patterns. Results stress the relevance of the choice of the baseline rural station in terms of temporal variability related to the sugarcane harvesting cycle.