Improving urban thermal profile with trees and water features

Abstract

In a tropical city with dry periods, the potential for high humidity to control the air temperature by two processes was investigated: the impounding of water bodies and arborisation in urban design. Air temperature and humidity were monitored in eight points in a zone of 250 000 m2. Three of them had detailed site characteristics. Point A was located on the margin of a dam in São José do Rio Preto, Brazil. Point B was located 200 m away from the margin in a sealed soil and low built density area. Point C was located 400 m northward under a tree. These three points were connected by a vegetated corridor, thus the environment remained susceptible to prevailing winds. A weather station, located southeast of the area, supplied the temperature, humidity, wind speed and wind direction data of the rural environment. The temperature above the water body margin registered 2·5°C lower than the rural environment. The water body increased the humidity by an average of 5·08 g/m3 more in the surroundings than near the tree crown. The results show that the presence of moisture could be applied as a thermal comfort strategy in this city, with the support of public policies to create open area systems and urban parks.