Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 16, 4641-4659, 2016
https://doi.org/10.5194/acp-16-4641-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
14 Apr 2016
Using beryllium-7 to assess cross-tropopause transport in global models
Hongyu Liu1, David B. Considine2,a, Larry W. Horowitz3, James H. Crawford2, Jose M. Rodriguez4, Susan E. Strahan4,5, Megan R. Damon4,6, Stephen D. Steenrod4,5, Xiaojing Xu7, Jules Kouatchou4,6, Claire Carouge8,b, and Robert M. Yantosca8 1National Institute of Aerospace, Hampton, VA, USA
2NASA Langley Research Center, Hampton, VA, USA
3NOAA Geophysical Fluid and Dynamics Laboratory, Princeton, NJ, USA
4NASA Goddard Space Flight Center, Greenbelt, MD, USA
5Universities Space Research Association, Columbia, MD, USA
6Science Systems and Applications, Inc., Lanham, MD, USA
7Science Systems and Applications, Inc., Hampton, VA, USA
8John A. Paulson School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
anow at: NASA Headquarters, Washington, D.C., USA
bnow at: ARC Centre of Excellence for Climate System Science, University of New South Wales, Sydney, Australia
Abstract. We use the Global Modeling Initiative (GMI) modeling framework to assess the utility of cosmogenic beryllium-7 (7Be), a natural aerosol tracer, for evaluating cross-tropopause transport in global models. The GMI chemical transport model (CTM) was used to simulate atmospheric 7Be distributions using four different meteorological data sets (GEOS1-STRAT DAS, GISS II′ GCM, fvGCM, and GEOS4-DAS), featuring significantly different stratosphere–troposphere exchange (STE) characteristics. The simulations were compared with the upper troposphere and/or lower stratosphere (UT/LS) 7Be climatology constructed from  ∼  25 years of aircraft and balloon data, as well as climatological records of surface concentrations and deposition fluxes. Comparison of the fraction of surface air of stratospheric origin estimated from the 7Be simulations with observationally derived estimates indicates excessive cross-tropopause transport at mid-latitudes in simulations using GEOS1-STRAT and at high latitudes using GISS II′ meteorological data. These simulations also overestimate 7Be deposition fluxes at mid-latitudes (GEOS1-STRAT) and at high latitudes (GISS II′), respectively. We show that excessive cross-tropopause transport of 7Be corresponds to overestimated stratospheric contribution to tropospheric ozone. Our perspectives on STE in these meteorological fields based on 7Be simulations are consistent with previous modeling studies of tropospheric ozone using the same meteorological fields. We conclude that the observational constraints for 7Be and observed 7Be total deposition fluxes can be used routinely as a first-order assessment of cross-tropopause transport in global models.

Citation: Liu, H., Considine, D. B., Horowitz, L. W., Crawford, J. H., Rodriguez, J. M., Strahan, S. E., Damon, M. R., Steenrod, S. D., Xu, X., Kouatchou, J., Carouge, C., and Yantosca, R. M.: Using beryllium-7 to assess cross-tropopause transport in global models, Atmos. Chem. Phys., 16, 4641-4659, https://doi.org/10.5194/acp-16-4641-2016, 2016.
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We assess the utility of cosmogenic beryllium-7, a natural aerosol tracer, for evaluating cross-tropopause transport in global models. We show that model excessive cross-tropopause transport of beryllium-7 corresponds to overestimated stratospheric contribution to tropospheric ozone. We conclude that the observational constraints for beryllium-7 and observed beryllium-7 total deposition fluxes can be used routinely as a first-order assessment of cross-tropopause transport in global models.
We assess the utility of cosmogenic beryllium-7, a natural aerosol tracer, for evaluating...
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