A quantitative description of the Oklahoma City urban heat island

Over the past several decades, increased emphasis has been placed on obtaining a detailed understanding of the spatial and temporal extent of urban heat islands (UHIs). With the deployment of the Oklahoma City Micronet (OKCNET) in 2008, and associated observations of atmospheric variables at high spatial (~3 km average station spacing) and temporal (1-minute) resolutions, a unique opportunity existed to gain valuable understanding of the variability of the UHI over a range of atmospheric conditions. As such, this project used OKCNET and Oklahoma Mesonet data to quantify the intensity and spatial distribution of the UHI in Oklahoma City from 1 June 2008 through 31 December 2009. After an extensive filtering process was applied, approximately 200 days displayed an urban heat island signature. From this dataset, the spatial and temporal variability was analyzed through the use of histograms and various spatial plots. The key results include that, (1) under ideal conditions, the magnitude of the composite UHI yielded a maximum value of 5.2°C, and (2) a “dry island” existed within the central business district (CBD) with composite relative humidity values 32% less than those in the rural areas outside of the Oklahoma City metropolitan area.