| Summary: | In this study, a relatively long-term (August 2001 - December 2002) measurement
campaign o f radiation, energy and atmospheric CO₂ fluxes was conducted in a fairly
homogeneous suburb of Vancouver, British Columbia (Sunset site).
Examination of radiative flux densities revealed that the incoming and outgoing short and
longwave radiation followed expected patterns throughout the year, and at the diurnal
time scale. Energy fluxes demonstrated more complex patterns. Sensible heat dominated
throughout the year. Latent heat was lower than expected. The reasons for this are
difficult to determine with confidence but are thought to be at least partially related to
low data coverage during the winter. The Sunset site has also become more built over the
years with natural surfaces transformed into impervious surfaces that more readily accept
heat. The role of heat storage played an important role in the energy balance at the
diurnal time scale.
The annual pattern of CO₂ followed expected seasonal trends, with the lowest concentrations recorded in the summer corresponding to the peak in photosynthesis.
Diurnal trends of CO₂ concentrations appear to be at least partly linked to the pattern of
fossil fuel consumption. A characteristic peak in concentrations at the diurnal time scale was seen in the morning that coincided with the morning rush hour. The pattern of CO₂
fluxes proved more difficult to interpret. Examination of annual CO₂ flux patterns
revealed few negative fluxes indicating that the site was a source for CO₂ for most of the
year. The diurnal pattern of CO₂ fluxes closely resembled patterns observed in other
urban areas, but of particular interest at the Sunset site was an apparent relationship
between wind direction and flux strength. Throughout the year, when the wind was
coming from the direction of a nearby busy intersection, fluxes were higher than when
the wind was coming from all other directions. This indicates that fluxes may not be well
mixed at the sensor height. This directional bias was not observed in the fluxes of heat or
water vapour indicating that there may be significant spatial differences in the sources of
CO₂ and/or an inequality in the transfer efficiencies of different entities. === Arts, Faculty of === Geography, Department of === Graduate
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