Uncertainties in modelling heterogeneous chemistry and Arctic ozone depletion in the winter 2009/2010 1Alfred Wegener Institute for Polar and Marine Research, Potsdam, Germany
17 Apr 2013
2Institute of Energy and Climate Research – Stratosphere (IEK-7), Forschungszentrum Jülich, Jülich, Germany
3NorthWest Research Associates, Inc., Socorro, New Mexico, USA
4New Mexico Institute of Mining and Technology, Socorro, New Mexico, USA
5Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
6University of York, York, UK
7Old Dominion University, Norfolk, VA, USA
8Institute of Meteorology and Climate Research, Karlsruhe Institute of Technology, Karlsruhe, Germany
9University of Wuppertal, Department of Physics, Wuppertal, Germany
10ISAC-CNR, Bologna, Italy
11Central Aerological Observatory, Dolgoprudny, Russia
Received: 13 September 2012 – Published in Atmos. Chem. Phys. Discuss.: 05 October 2012 Abstract. Stratospheric chemistry and denitrification are simulated for the Arctic
winter 2009/2010 with the Lagrangian Chemistry and Transport Model ATLAS.
A number of sensitivity runs is used to explore the impact of uncertainties in
chlorine activation and denitrification on the model results. In particular,
the efficiency of chlorine activation on different types of liquid aerosol
versus activation on nitric acid trihydrate clouds is examined.
Additionally, the impact of changes in reaction rate coefficients,
in the particle number density of polar stratospheric clouds,
in supersaturation, temperature or the extent of denitrification is
Results are compared to satellite measurements
of MLS and ACE-FTS and to in-situ measurements onboard the Geophysica
aircraft during the RECONCILE measurement campaign.
It is shown that even large changes in the
underlying assumptions have only a small impact on the modelled ozone
loss, even though they can cause considerable differences in chemical
evolution of other species and in
denitrification. Differences in column ozone between the sensitivity runs
stay below 10% at the end of the winter.
Chlorine activation on liquid aerosols alone is able to explain the
observed magnitude and morphology of the mixing ratios of
active chlorine, reservoir gases and ozone.
This is even true for binary aerosols (no uptake of HNO3 from
the gas-phase allowed in the model). Differences in chlorine
activation between sensitivity runs are within 30%.
Current estimates of nitric acid trihydrate (NAT) number density and
supersaturation imply that, at least for this winter, NAT
clouds play a relatively small role compared to liquid clouds in
The change between different reaction rate coefficients for liquid
or solid clouds has only a minor impact on ozone loss
and chlorine activation in our sensitivity
Revised: 12 March 2013 – Accepted: 24 March 2013 – Published: 17 April 2013
Citation: Wohltmann, I., Wegner, T., Müller, R., Lehmann, R., Rex, M., Manney, G. L., Santee, M. L., Bernath, P., Sumińska-Ebersoldt, O., Stroh, F., von Hobe, M., Volk, C. M., Hösen, E., Ravegnani, F., Ulanovsky, A., and Yushkov, V.: Uncertainties in modelling heterogeneous chemistry and Arctic ozone depletion in the winter 2009/2010, Atmos. Chem. Phys., 13, 3909-3929, doi:10.5194/acp-13-3909-2013, 2013.