The suburban energy balance: Methodological considerations and results for a mid-latitude west coast city under winter and spring conditions



Previous measurements of the urban energy balance primarily have been conducted in summertime. This paper reports the first extended set of winter-spring-time energy balance measurements for a city. The study was conducted in a suburb of Vancouver, British Columbia, from January to June 1987. It included hourly measurements of net all-wave radiation, sensible heat flux and the Bowen ratio. The anthropogenic and storage heat fluxes were modelled. A dynamic source area model was employed to ensure the modelled parameters were consistent spatially with the measured turbulent fluxes. The winter-spring urban energy balances observed in this study are different to those reported for summertime conditions at the same site. The fluxes for the entire period are not symmetrical about solar noon. Hence earlier interpretations possibly should be modified. Apart from this feature the spring season balances are similar to those reported for the summertime in terms of relative importance of individual fluxes. The wintertime energy balance appears to be different to that of spring and summer. The most noticeable feature is the increased importance of the latent heat flux, which on average is the largest output flux in the balance. A secondary, more expected feature, is the increased importance of anthropogenic heat flux as an input in winter.