An analysis of the circulation characteristics and energy budget of a dry, asymmetric, east-west urban canyon. II. Energy budget



This study presents partial energy budget evaluations for a dry east-west oriented urban canyon in Columbus, Ohio, based on canyon-top measurements of net radiation and the turbulent and circulation-related components of the sensible heat flux. While net radiation data were similar to those reported in previous studies, the sensible heat exchanges were small in absolute magnitude, showed a “flat” diurnal regime and were uncorrelated with the net radiation. These results suggest a minimal degree of coupling by heat exchange between the canyon air space and 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 advective term (through the canyon ends and top) may be instrumental in accounting for the residual. However, definitive conclusions were precluded by the absence of simultaneous evaluations of all the energy budget components. The need for such studies at canyon sites with diverse structures and fabrics is emphasized.