Quantification of thermal bioclimate for the management of urban design in Mediterranean climate of Barcelona, Spain.

Abstract

In order to contribute to the sustainability of the outdoor environment, knowledge about the urban thermal bioclimate should be transferred into climatic guidelines for planning. The general framework of this study responds to the need of analyzing thermal bioclimate in Mediterranean climate regions and its influence as an urban design factor. The paper analyzes the background of the urban climate and thermal bioclimate conditions in Barcelona (Spain), through the effect of shade conditions and wind speed variations. Simulations of shade and wind speed variations were performed to evaluate changes in thermal bioclimate due to modifications in urban morphology. Air temperature, relative humidity, wind speed, and solar radiation for the period from January, 2001 to January, 2015 were used to calculate physiologically equivalent temperature (PET) using the RayMan model. The results demonstrate that shade is the most important strategy to improve urban microclimatic conditions. In Barcelona, human thermal comfort conditions can be improved by shade and wind speed increase in terms of PET above 23°C and by a wind speed decrease for thresholds of PET below 18°C. Heat stress situations can be mitigated by shade and wind speed increase in conditions above 35 and 45°C, respectively. The results of the study are an important contribution for urban planners, due to their possibilities and potential for the description of microclimatic conditions in Mediterranean climate regions. The knowledge is useful for improved human thermal comfort conditions, from the suitable configuration of urban form and architecture.