Shade maps for prioritizing municipal microclimatic action in hot climates: Learning from Tel Aviv-Yafo

Abstract

This article presents a methodology for evaluating microclimatic summer conditions across an entire city, focusing on the provision of outdoor shade as a primary comfort indicator. Based on high-resolution 2.5D and 3D mapping of buildings, ground surfaces, and tree canopies in Tel Aviv-Yafo, a city of hot-summer Mediterranean climate, we employed a detailed calculation of solar exposure of streets and open spaces (public and private) using commonly available GIS algorithms. The raw results of these calculations were used for calculating summer Shade Index values for every street segment and neighbourhood of the city, which were then plotted to a comprehensive 'shade maps' reflecting the city's spatial hierarchy of shade. The shade maps, combined with analysis of tree canopy cover on similar scales, enabled to relate building and tree morphologies to outdoor shade conditions. For prioritizing intervention of local planning authorities in improving poor shade conditions or conserving highly-shaded locations, we related the climatic analysis to space-syntax classification of streets according to their potential to attract pedestrian movement, and produced a city-wide map that highlighted streets that have high pedestrian movement potential while requiring high levels of shade intensification or conservation.