Atmos. Chem. Phys. Discuss., 9, 11005-11050, 2009
www.atmos-chem-phys-discuss.net/9/11005/2009/
doi:10.5194/acpd-9-11005-2009
© Author(s) 2009. This work is distributed
under the Creative Commons Attribution 3.0 License.
Review Status
This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Uncertainties in atmospheric chemistry modelling due to convection and scavenging parameterisations – Part 1: Implications for global modelling
H. Tost1,2, M. G. Lawrence1, and P. Jöckel1
1Atmospheric Chemistry Department, Max Planck Institute for Chemistry, P.O. Box 3060, 55020 Mainz, Germany
2EEWRC, The Cyprus Institute, Nicosia, Cyprus

Abstract. Moist convection in global modelling contributes significantly to the transport of energy, momentum, water and trace gases within the troposphere. Since convective clouds are on a scale too small to be resolved in a global model their effects have to be parameterised. However, the whole process of moist convection and especially its parameterisation are associated with uncertainties. In contrast to previous studies we address the impact of convection on trace species by examining simulations with five different convection schemes, rather than neglecting the convective transport for some or all compounds. This permits an uncertainty analysis due to the process formulation, without the inconsistencies inherent in entirely neglecting deep convection or convective tracer transport for one or more tracers.

Both the simulated mass fluxes and tracer distributions are analysed. Investigating the distributions of compounds with different characteristics, e.g., lifetime, chemical reactivity, solubility and source distributions, some differences can be attributed directly to the transport of these compounds, whereas others are more related to indirect effects, such as the transport of precursors, chemical reactivity in certain regions, and sink processes. The shorter-lived a compound is, the larger the differences and consequently the uncertainty due to the convection parameterisation, i.e., reaching up to ±100% for short-lived compounds, whereas for long-lived compounds like CO or O3 the mean differences between the simulations are less than 25%.


Citation: Tost, H., Lawrence, M. G., and Jöckel, P.: Uncertainties in atmospheric chemistry modelling due to convection and scavenging parameterisations – Part 1: Implications for global modelling, Atmos. Chem. Phys. Discuss., 9, 11005-11050, doi:10.5194/acpd-9-11005-2009, 2009.
 
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