Parameterisation and impact of aerosol uptake of HO2 on a global tropospheric model Institute for Climate and Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
04 Nov 2011
Received: 18 Apr 2011 – Published in Atmos. Chem. Phys. Discuss.: 01 Jun 2011 Abstract. HO2 is an important atmospheric trace gas, whose sink to aerosol is
poorly understood yet significant. Previous parameterisations of the rate of
uptake have been limited by the lack of laboratory studies.
This paper creates a parameterisation for γHO2
based on the available laboratory studies. The calculated global mean
γHO2 is 0.028, significantly lower than previous work (0.2).
Modelled concentrations of HO2 show significant regional sensitivity
to the value of γHO2 (up to +106% at the surface with
of γHO2 in this work as compared with a value of 0.2),
but global sensitivity is small (+3.2%). The modelled response in
O3 is also highly regional, being up to +27% at the surface over
China, and only
+0.3% globally (with the parameterisation of γHO2 in
this work as compared with a value of 0.2). The impact of
γHO2 on sulfate is more complex, with up to +16% over
China and −5% over high latitudes, resulting in a global change of +1.2%
(with the parameterisation of γHO2 in
this work as compared with a value of 0.2). Uncertainty in the reaction
mechanism and hence products (previously assumed to be H2O2)
impacts the processing of sulfur and hence aerosol loads. Further laboratory
studies are desirable to constrain the rate of reaction and to elucidate
the reaction mechanism and products.
Revised: 07 Oct 2011 – Accepted: 20 Oct 2011 – Published: 04 Nov 2011
Citation: Macintyre, H. L. and Evans, M. J.: Parameterisation and impact of aerosol uptake of HO2 on a global tropospheric model, Atmos. Chem. Phys., 11, 10965-10974, doi:10.5194/acp-11-10965-2011, 2011.