HR: 0800h
AN: A51A-0108
TI: The effect of anthropogenic emissions corrections on the seasonal cycle of atmospheric CO₂
AU: Brooks, B J
EM: bjorn@climatemodeling.org
AF: Oak Ridge National Lab, Oak Ridge, TN, United States
AU: Hoffman, F M
EM: forrest@climatemodeling.org
AF: Oak Ridge National Lab, Oak Ridge, TN, United States
AU: Mills, R T
EM: rmills@ornl.gov
AF: Oak Ridge National Lab, Oak Ridge, TN, United States
AU: Erickson, D J
EM: ericksondj@ornl.gov
AF: Oak Ridge National Lab, Oak Ridge, TN, United States
AU: Blasing, T J
EM: blasingtj@ornl.gov
AF: Oak Ridge National Lab, Oak Ridge, TN, United States
AB: A previous study (Erickson et al. 2008) approximated the monthly global emission estimates of anthropogenic CO₂ by applying a 2-harmonic Fourier expansion with coefficients as a function of latitude to annual CO₂ flux estimates derived from United States data (Blasing et al. 2005) that were extrapolated globally. These monthly anthropogenic CO₂ flux estimates were used to model atmospheric concentrations using the NASA GEOS-4 data assimilation system. Local variability in the amplitude of the simulated CO₂ seasonal cycle were found to be on the order of 2-6 ppmv. Here we used the same Fourier expansion to seasonally adjust the global annual fossil fuel CO₂ emissions from the SRES A2 scenario. For a total of four simulations, both the annual and seasonalized fluxes were advected in two configurations of the NCAR Community Atmosphere Model (CAM) used in the Carbon-Land Model Intercomparison Project (C-LAMP). One configuration used the NCAR Community Land Model (CLM) coupled with the CASA′ (carbon only) biogeochemistry model and the other used CLM coupled with the CN (coupled carbon and nitrogen cycles) biogeochemistry model. All four simulations were forced with observed sea surface temperatures and sea ice concentrations from the Hadley Centre and a prescribed transient atmospheric CO₂ concentration for the radiation and land forcing over the 20^th century. The model results exhibit differences in the seasonal cycle of CO₂ between the seasonally corrected and uncorrected simulations. Moreover, because of differing energy and water feedbacks between the atmosphere model and the two land biogeochemistry models, features of the CO₂ seasonal cycle were different between these two model configurations. This study reinforces previous findings that suggest that regional near-surface atmospheric CO₂ concentrations depend strongly on the natural sources and sinks of CO₂, but also on the strength of local anthropogenic CO₂ emissions and geographic position. This work further attests to the need for remotely sensed CO₂ observations from space.
UR: http://www.climatemodeling.org/c-lamp/
DE: [0315] ATMOSPHERIC COMPOSITION AND STRUCTURE / Biosphere/atmosphere interactions
DE: [0322] ATMOSPHERIC COMPOSITION AND STRUCTURE / Constituent sources and sinks
DE: [0345] ATMOSPHERIC COMPOSITION AND STRUCTURE / Pollution: urban and regional
DE: [1622] GLOBAL CHANGE / Earth system modeling
SC: Atmospheric Sciences (A)
MN: 2009 Fall Meeting