Urban Surfaces Temperatures and Turbulent Properties of Heat Transfer Within the Urban Roughness Sublayer. Submitted to: 15th Conference on Boundary Layer and Turbulence, Wageningen, Holland, July 2002
S. Pistinner, E. Fattal, E. Gavze Israel Institute for Biological Research, P.O.B 19, Ness-Ziona, 74100, Israel
Three pairs of ultrasonic anemometers were deployed above a roof top, deep within urban fetch of a city in Israel during summer. Each pair was mounted at a heights of 2 and 6 meters above the roof level. The pairs were seven meters apart from each other, thus covering a third of the roof length. The roof height was roughly 10 meters above the street level, so that in terms of normalized heights the measurements were performed at 1.2 and 1.6. The sampling rate of each anemometer was 10Hz and data were collected on the same card to ensure synchronization. In addition roof temperature was measured by thermocouples, located immediately beneath the anemometers.
We found that an IBL structure, with respect to the heat flux, was formed upstream of the edge of the roof. A similar measurement with a single pair in an open area, roughly in the same time of year, revealed an insignificant variation with height. Roof surface temperature measurements exhibited differences of up to 5 degrees Celsius during day time.
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