HR: 13:40h
AN: A13G-01 INVITED     [Abstracts]
TI: Simulation and Observation of Global Variations in Surface Exchange and Atmospheric Mixing Ratios of CO2
AU: * Denning, A
EM: denning@atmos.colostate.edu
AF: Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371 United States
AU: Conner-Gausepohl, S
EM: sheri@atmos.colostate.edu
AF: Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371 United States
AU: Kawa, S
EM: kawa@maia.gsfc.nasa.gov
AF: Goddard Space Flight Center, National Aeronautics and Space Administration, Greenbelt, MD 20771 United States
AU: Baker, I T
EM: baker@atmos.colostate.edu
AF: Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371 United States
AU: Zhu, Z
EM: zhu@mulan.gsfc.nasa.gov
AF: Goddard Space Flight Center, National Aeronautics and Space Administration, Greenbelt, MD 20771 United States
AU: Brown, M
EM: molly.brown@gsfc.nasa.gov
AF: Goddard Space Flight Center, National Aeronautics and Space Administration, Greenbelt, MD 20771 United States
AU: Vay, S
EM: s.a.vay@larc.nasa.gov
AF: Langley Research Center, National Aeronautics and Space Administration, Hampton, VA 23681 United States
AU: Wofsy, S C
EM: scw@io.harvard.edu
AF: Pierce Hall, 100 A, Harvard University, Cambridge, MA 02138 United States
AU: Philpott, A
EM: andrew@atmos.colostate.edu
AF: Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371 United States
AU: Collatz, G
EM: jcollatz@biome.gsfc.nasa.gov
AF: Goddard Space Flight Center, National Aeronautics and Space Administration, Greenbelt, MD 20771 United States
AU: Schaefer, K
EM: kevin@atmos.colostate.edu
AF: NOAA Climate Monitoring and NOAA Climate Monitoring and Diagnostics Lab, 325 Broadway, Boulder, CO 80303 United States
AU: Kleist, J
EM: johnk@atmos.colostate.edu
AF: Department of Atmospheric Science, Colorado State University, Fort Collins, CO 80523-1371 United States
AB: We have performed a simulation of hourly variations of terrestrial surface fluxes and the atmospheric mixing ratio of carbon dioxide from January 1, 2000 through December 31, 2004, and have evaluated the simulation by comparison to a number of observations. Terrestrial photosynthesis and ecosystem respiration were computed using the Simple Biosphere Model (SiB), driven by diurnally-varying weather analyzed by the NASA Goddard Earth Observing System (GEOS) Data Assimilation System (DAS), with vegetation parameters specified using imagery from the NOAA Advanced High Resolution Radiometer (AVHRR). CO2 emissions due to the combustion of fossil fuel and to air-sea gas exchange were also prescribed as boundary forcing to the atmospheric transport Parameterized Chemical Transport model (PCTM). Preliminary results showed reasonable agreement with spatial and synoptic variations, but suffered from a systematic offset with respect to the observed seasonal cycle of CO2 at many flask observing stations. Subsequent analysis showed that these problems were traceable to temporal interpolation of the satellite vegetation imagery and the treatment of leaf-to-canopy scaling in SiB, which have both been substantially revised as a result of these analyses. Comparisons to eddy covariance data at several sites, to tower-based continuous observations of CO2 mixing ratio, and to data collected by airborne sampling show that the coupled simulation successfully captures many features of the observed temporal and spatial variations of terrestrial surface exchange and atmospheric transport of CO2. The simulations demonstrate the sensitivity of both surface exchange and atmospheric transport of CO2 to synoptic weather events in middle latitudes, and suggest that high-frequency variations in continental [CO2] data can be interpreted in terms of surface flux anomalies.
UR: http://biocycle.atmos.colostate.edu
DE: 0322 Constituent sources and sinks
DE: 0365 Troposphere: composition and chemistry
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0426 Biosphere/atmosphere interactions (0315)
DE: 0466 Modeling
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005