The Role of Rural Variability in Urban Heat Island Determination for Phoenix, Arizona

Abstract

The effect of rural variability in calculating the urban heat island effect for Phoenix, Arizona, was examined. A dense network of temperature and humidity sensors was deployed across different land uses on an agricultural farm southeast of Phoenix for a 10-day period in April 2002. Temperature data from these sensors were compared with data from Sky Harbor Airport in Phoenix (an urban station) to assess the urban heat island effect using different rural baselines. The smallest and largest temperature differences between locations on the farm at a given time were 0.8° and 5.4°C, respectively. A t test revealed significant temperature differences between stations on the farm over the entire study period. Depending on the choice of rural baselines, the average and maximum urban heat island effects ranged from 9.4° to 12.9°C and from 10.7° to 14.6°C, respectively. Comparison of land cover types of the agricultural farm and land cover percentages in the Phoenix urban fringe was performed with satellite imagery. Classification of the entire urban fringe by using satellite imagery allowed for the local farm data to be scaled to a regional level.