HR: 14:35h
AN: B43C-04    [Abstracts]
TI: CO2 Dynamics in Atmospheric Boundary Layer over Boreal Forest: Integrating Aircraft CO2 Concentration Profiles with Tower-Based Flux Measurements.
AU: * Shashkov, A
EM: Alexander.Shashkov@ec.gc.ca
AF: Meteorological Service of Canada, 4905 Dufferin Str., Toronto, ON M3H 5T4 Canada
AU: Chan, D
EM: Douglas.Chan@ec.gc.ca
AF: Meteorological Service of Canada, 4905 Dufferin Str., Toronto, ON M3H 5T4 Canada
AU: Higuchi, K
EM: Kaz.Higuchi@ec.gc.ca
AF: Meteorological Service of Canada, 4905 Dufferin Str., Toronto, ON M3H 5T4 Canada
AU: Worthy, D
EM: Doug.Worthy@ec.gc.ca
AF: Meteorological Service of Canada, 4905 Dufferin Str., Toronto, ON M3H 5T4 Canada
AB: The atmospheric boundary layer (ABL) has an important role in the global carbon cycle since it acts as an interface between the global free troposphere and the surface sinks and sources of carbon dioxide. Multiple processes in a wide range of spatial and temporal scales are contributing to the dynamics of the CO2 concentration field in the ABL. While different research approaches provide insights on the processes in different scale domains, the relationship among the processes of different scales represents a significant challenge. On the diurnal time scale, eddy correlation CO2 flux measurements have footprints of about 1 km2, while CO2 concentration measurements have footprints of the order of 1000 km2. Therefore it is necessary to understand the relationship between the CO2 flux and concentration measurements to scale up the small scale flux measurements to the regional scale concentration measurements. In this study, we examined the flux-concentration relationship in the ABL at a boreal forest site in Saskatchewan, Canada; using a combination of tower flux measurements, tower CO2 concentration measurements, and aircraft profile concentration measurements. Some cases were illustrated using coupled biosphere-atmosphere model simulations. The results suggest that in the night time with typically low wind speed, the CO2 concentration in the shallow stably stratified ABL is dominated by the local CO2 flux. While comparison of boundary layer CO2 budget changes estimated from aircraft profiles with tower eddy covariance flux measurements indicates that the daytime CO2 concentration in the deep well-mixed ABL is strongly influenced by atmospheric transport, and the atmospheric transport is driven by mesoscale and synoptic scale processes. Therefore, understanding of the mesoscale and synoptic scale atmosphere-biosphere interaction is important in the flux-concentration relationship.
DE: 0315 Biosphere/atmosphere interactions
DE: 0400 Biogeosciences
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting