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A Test of Sensitivity to Convective Transport in a Global Atmospheric CO2 SimulationTwo approximations to convective transport have been implemented in an offline chemistry transport model (CTM) to explore the impact on calculated atmospheric CO2 distributions. GlobalCO2 in the year 2000 is simulated using theCTM driven by assimilated meteorological fields from the NASA s Goddard Earth Observation System Data Assimilation System, Version 4 (GEOS-4). The model simulates atmospheric CO2 by adopting the same CO2 emission inventory and dynamical modules as described in Kawa et al. (convective transport scheme denoted as Conv1). Conv1 approximates the convective transport by using the bulk convective mass fluxes to redistribute trace gases. The alternate approximation, Conv2, partitions fluxes into updraft and downdraft, as well as into entrainment and detrainment, and has potential to yield a more realistic simulation of vertical redistribution through deep convection. Replacing Conv1 by Conv2 results in an overestimate of CO2 over biospheric sink regions. The largest discrepancies result in a CO2 difference of about 7.8 ppm in the July NH boreal forest, which is about 30% of the CO2 seasonality for that area. These differences are compared to those produced by emission scenario variations constrained by the framework of Intergovernmental Panel on Climate Change (IPCC) to account for possible land use change and residual terrestrial CO2 sink. It is shown that the overestimated CO2 driven by Conv2 can be offset by introducing these supplemental emissions.
Document ID
20070031224
Acquisition Source
Goddard Space Flight Center
Document Type
Reprint (Version printed in journal)
Authors
Bian, H.
(Maryland Univ. Baltimore County Baltimore, MD, United States)
Kawa, S. R.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Chin, M.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Pawson, S.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Zhu, Z.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Rasch, P.
(National Center for Atmospheric Research Boulder, CO, United States)
Wu, S.
(Harvard Univ. Cambridge, MA, United States)
Date Acquired
August 23, 2013
Publication Date
November 1, 2006
Publication Information
Publication: Tellus: Series B Chemical and Physical Meteorology
Publisher: International Meteorological Inst.
Volume: 58
Issue: 5
Subject Category
Meteorology And Climatology
Distribution Limits
Public
Copyright
Other

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