presented by Jielun Sun (NCAR/MMM)
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.
Seminar is from
3:30pm tp 4:30 pm in FL2 Room 1022
on Thursday, March 31, 2005.
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