A preliminary study on the local cool-island intensity of Taipei city parks

That green-spaces relieve urban heat is well known in urban landscape planning. Scientific information on what kinds of green-spaces best reduce heat, however, is still largely unknown. This is a preliminary study aimed at (1) devising a method to detect and compare the local cool-island intensities of various urban parks; (2) verifying that this local cool-island intensity differs among parks; (3) determining whether this local cool-island intensity is related to park characteristics. Results from air-temperature measurements in and around 61 Taipei city parks showed that urban parks were on average cooler than their surroundings, confirming the term "urban cool-islands." However, approximately one-fifth of the parks were warmer than their urban surroundings. At noon in summer, parks with >= 50% paved coverage and little tree- and shrub-cover were on average warmer than their surroundings. Large parks were on average cooler than the smaller ones, but this relationship was non-linear. In Taipei, parks differed in their local cool-island intensity and this intensity can be related to park characteristics. Before further details concerning better planning and design approaches to mitigate urban heat-islands can be addressed, a neighborhood-scaled understanding of the urban microclimate is first needed as a basis. (C) 2006 Elsevier B.V. All rights reserved.