MMM SEMINAR NCAR
National Center for
Atmospheric Research
Boulder, CO
The carbon dioxide transport at the Niwot-Ridge AmeriFlux site, especially for the transport that is not monitored by the AmeriFlux network, was investigated in both gravity and streamline coordinate systems. We found that the vertical and horizontal transports of CO2 were larger than, or of the same magnitude as, the vertical turbulent transport of CO2 at this complex terrain site. The nighttime drainage flow and the daytime upslope flow played significant roles in the CO2 transport. The horizontal turbulent transport of CO2 had approximately the same magnitude as the vertical turbulent transport of CO2. The drainage flow associated with the local gullies dissecting the large-scale terrain was also responsible for transporting CO2. The drainage flow was sensitive to the atmospheric stability and was normally confined below the maximum leaf-density level. Turbulent mixing due to wind gusts at night sometimes eliminated the gully drainage flow, while the drainage flow associated with the main slope survived the mixing. The sudden depletion of the boundary-layer CO2 storage in the morning transition period was associated with photosynthesis, upslope flow, and buoyancy flux venting. The results in this study will have significant impacts on estimating of regional CO2 budgets, especially over complex terrain.
Thursday, 31 March 2005,
3:30 PM
Refreshments 3:15 PM
NCAR-Foothills Laboratory
3450 Mitchell Lane
Bldg 2 Auditorium (Rm1022)