89th American Meteorological Society Annual Meeting

Monday, 12 January 2009: 5:00 PM
Estimating thermal responsiveness of local-scale climate 'zones' with a numerical modeling approach
Room 124A (Phoenix Convention Center)
Scott Krayenhoff, University of British Columbia, Vancouver, BC, Canada; and I. Stewart and T. Oke
Poster PDF (417.7 kB)
The diversity of ‘urban' and ‘rural' landscapes at the local scale suggests that a more nuanced definition of the urban heat island is appropriate. Stewart and Oke propose thermal climate ‘zones' to standardize the classification and intercomparison of locally-produced surface climates. Classification is based on the capacity of a site to modify its thermal microclimate. This capacity is due to its particular mix of radiative, thermal, roughness, moisture and anthropogenic properties. In order to scale this capacity we simulate the thermal responsiveness of the suggested zones using a typical set of input properties. Several models that together treat surface-atmosphere interaction and vertical boundary-layer exchange are aggregated in a novel way in order to estimate the thermal responsiveness of surfaces typifying a variety of ‘urban', ‘agricultural', ‘natural' and ‘mixed' climate zones. The combined model is compared with observations and includes urban and soil-vegetation surface schemes, a 1-D boundary layer model and parameterizations of atmospheric radiation. The treatment of urban vegetation and its effect on turbulent flux partitioning is discussed.

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