AN ANALYSIS OF THE CIRCULATION CHARACTERISTICS AND ENERGY BUDGET OF ADRY, ASYMMETRIC, EAST-WEST URBAN CANYON .2. ENERGY BUDGET

This study presents partial energy budget evaluations for a dry east-w est oriented urban canyon in Columbus, Ohio, based on canyon-top measu rements of net radiation and the turbulent and circulation-related com ponents of the sensible heat flux. While net radiation data were simil ar to those reported in previous studies, the sensible heat exchanges were small in absolute magnitude, showed a 'flat' diurnal regime and w ere uncorrelated with the net radiation. These results suggest a minim al degree of coupling by heat exchange between the canyon air space an d the urban boundary layer above roof level. Speculations are offered on the nature of the unmeasured residual in the canyon energy budget. Evidence suggests that both a substrate heat flux and a significant ad vective term (through the canyon ends and top) may be instrumental in accounting for the residual. However, definitive conclusions were prec luded by the absence of simultaneous evaluations of all the energy bud get components. The need for such studies at canyon sites with diverse structures and fabrics is emphasized.