Quantification of turbulent heat fluxes for adaptation strategies within urban planning

In: International journal of climatology : a journal of the Royal Meteorological Society, (2012), S. ohne Seitenagabe
ISSN: 0899-8418
Zeitschriftenaufsatz / Fach: Geowissenschaften
Abstract:
DOI: 10.1002/joc.3437
With the objective of quantifying turbulent heat fluxes in areas with various types of urban land use to improve living and environmental conditions through better urban planning, comparative energy balance measurements using the eddy-covariance (EC) technique were conducted in Oberhausen (Germany) between 15 August 2010 and 15 April 2011. The results of this paper show that the sensible heat flux (QH) is 20% higher and that the latent heat flux (QE) is 90% lower at an urban site (URB) compared to a suburban site (SUB). Green spaces in cities counteract the growing thermal stresses on city dwellers and therefore represent a possible urban climate mitigation measure. This positive effect may be reduced or lost entirely during long periods of drought. The Bowen ratio (QH/QE) increased from 0.65 to 2.8 with decreasing soil moisture at the SUB, and the monthly average QE value decreased from 94 W m−2 (August 2010, heavy precipitation) to only 47 W m−2 (March 2011, dry period), providing impressive evidence of this relationship. Considering the aspects of urban climate, the creation of urban green spaces can only be effective if an optimum water supply is provided. Furthermore, additional planning recommendations are given for urban planners within cities located at mid-latitudes, as derived from the measured results.

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