Cool Neighborhoods: The Measurement of Small Scale Heat Islands
Rapid population influx in many Sunbelt cities has led to demands for converting natural areas to housing, many times by clear-cutting large tracts of land. This trend may be affecting the climate for existing and future residents and increasing energy bills. The heat island for large cities has been documented, however the impact of tree canopy on micro-climates in suburban environments has not been researched as much. Tree canopy in micro-climates has implications, both for preserving trees within recently constructed developments, as well as for tree-planting programs. To address this issue, temperature measurements were made over a one year period at three Melbourne, Florida sites. The results showed a forested nature park of 19 hectares to be consistently cooler during both summer days and nights than a residential development of 9 hectares and density of 4.6 houses per hectare with an extensive tall tree canopy. This development was, in turn, consistently cooler than a residential development of 37 hectares and density of 10.1 houses per hectare with very few trees. The average July air temperatures in 1992 for the forested undeveloped site, residential site with trees, and residential site without trees measured at the project's main stations were 26.2, 26.9 and 27.8°C respectively at a 2.5-meter height and 26.7, 27.0 and 27.7°C respectively at a 9-meter height. The 2.5-meter temperature differences were greater than 1°C between the two residential sites 93% of the time when both sites had wind speeds greater than 0.5 m/s. Mobile measurements were made on two summer days, with good agreement with the main stations. The mobile measurement made on a sunny day indicated significant localized warming at commercial sites adjacent to the residential development with trees.
Florida Solar Energy Center and Sonne, Jeffrey, "Cool Neighborhoods: The Measurement of Small Scale Heat Islands" (2000). FSEC Energy Research Center®. 631.