Integrating urban heat island influences into statistically downscaled climate projections in the Truckee Meadows, Nevada
AuthorHatchett, Benjamin James
AdvisorKoracin, Darko R
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The Truckee Meadows is a narrow, semi-arid valley located in the lee of the Sierra Nevada and includes the cities of Reno and Sparks, Nevada. Cities are usually warmer than the surrounding countryside, especially at night, due to changes in the surface energy budget. This effect is known as the urban heat island (UHI) and results in a decreased diurnal temperature range, increased urban water usage and cooling costs during the warm season and exacerbates public health problems associated with heat waves and air quality. An examination of the Truckee Meadows' trends in daily and monthly mean minimum temperatures during 1938-2010 identified an UHI. The maximum summer UHI exceeds the magnitude predicted as a function of population by the classical method of Oke (1976) by 2°C. The thermal perturbation of the UHI was not discernible in nearby upper-air rawinsonde sounding data which indicates the shallow, localized effect of this physical phenomenon. A synoptic climatology indicated that the North American Monsoon may provide favorable conditions for UHI development during the summer. Several methods for downscaling future temperature projections for the Truckee Meadows produced by global climate model data under three IPCC emissions scenarios (A1b, A2 and B2) for the future period 2041-2060 were examined. Results indicated that a bias correction and constructed analogs method with an additional bias correction step that incorporates the maximum UHI signal (1970-2009) is vital in producing robust results that include UHI effects for future urban resource planning and management. Further work is suggested focusing on the development of a fine spatial resolution observation network and physical sensitivity testing of the UHI via sub-kilometer scale numerical modeling efforts.