Extended Abstract (216K)9.7
Analysis of long-term observations of urban surface-atmosphere energy exchange
B Offerle, Indiana University, Bloomington, IN; and C. S. B. Grimmond, K. Fortuniak, T. R. Oke, and K. Klysik
Better understanding of local-scale urban meteorology is necessary in order to develop numerical climate models and to address a range of applied questions of concern to the health, comfort and safety of citizens. To date most urban observations of turbulent exchange and other energy balance components have been limited to short-duration campaigns, mainly at low density residential sites and in summer. Observations of the seasonal changes in energy balance fluxes are critical to developing and testing surface flux parameterizations as well as understanding local-scale meteorology. In November 2000, we began long-term continuous energy balance observations above the urban core of Lodz, Poland. The measurements include turbulent fluxes of sensible and latent heat, as well as individual components of the radiation balance and supplementary meteorological fields. Analysis of monthly ensemble energy balance fluxes shows daytime storage flux approximately equal in magnitude to sensible heat flux. Daytime Bowen ratios peak in May (>2) and decrease through the growing season, latent heat accounting for almost half of the monthly turbulent flux exchange. Wintertime observations show the strong influence of anthropogenic heat flux as suggested by energy consumption models (Klysik, 1996) Fluxes and flux partitioning correlate with surface cover derived from a surface structure and cover geographic information system (GIS) in conjunction with the calculated flux-footprint.
Session 9, Urban radiation and energy exchanges
Wednesday, 22 May 2002, 9:30 AM-12:15 PM
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