Summertime Urban Heat Island Mitigation: Propositions based on an Investigation of Intra-Urban Air Temperature Variations

Abstract

A normalization technique called “Paired Measurement Program” is utilized to analyze the effects of four land-use/land-cover patterns on intra-urban air temperature variations in Ann Arbor, Michigan, under different atmospheric stability conditions. The aim is to propose broad land-use control strategies for the mitigation of the negative effects of urban heat islands during the summer. The results show that unstable day-time atmospheric conditions produced the maximum intra-urban air temperature differences, with significant downtown-to-residential as well as residential-to-residential variations. Stable nights lead to significant temperature differences between the downtown location and each of the residential locations, but not between the residential locations. Vegetation shade influenced intra-urban temperature variations at day but not at night. This resulted in an admixture of cool and heat islands at day, but at night a more homogeneous, downtown-centered heat island was the norm. Based on these results, four propositions for the mitigation of the summer heat island effect in mid-latitude cities are made.