Risk and Exposure to Extreme Heat in Microclimates of Phoenix, AZ

Abstract

As rapid urban development continues, the impacts of temperature extremes on human health and comfort are expected to increase as threshold temperatures of human tolerance are crossed more frequently and for longer periods of time. This study examined extreme heat as an urban hazard throughout the Phoenix (Arizona, USA) metropolitan area during a four-day 2005 summer heat wave. Utilizing the Weather Research and Forecasting (WRF) model to simulate 2 m air temperature variability throughout the region, the distribution of threshold temperatures and heat exposure was examined in 40 diverse neighborhoods. Neighborhood residents also responded to a social survey about perceived temperatures and heat-related health problems during the summer of 2005. Results indicated that extreme heat was variably distributed throughout the neighborhoods; residents’ perceptions of temperature and self-reported experiences with heat-related illnesses were related to environmental conditions; the highest risk of exposure to extreme heat was among elderly, minority, and low-income residents; and land use/cover characteristics exhibited strong relationships with local threshold temperatures. Research contributions include the development of a geotechnical analysis method that could help cities to prepare for and respond to the most vulnerable residents during periods of extreme heat as well as the interrelation of regional atmospheric model results with socio-economic data.