Evaluation of stratospheric chlorine chemistry for the Arctic spring 2005 using modelled and measured OClO column densities 1University of Bremen, Institute of Environmental Physics, Germany
2University of Leeds, School of Chemistry Leeds, UK
3University of Leeds, School of Earth and Environment, Leeds, UK
Received: 20 Oct 2009 – Published in Atmos. Chem. Phys. Discuss.: 10 Dec 2009Abstract. Chlorine dioxide, OClO, column amounts retrieved from measurements of the
SCIAMACHY satellite instrument are presented and validated by comparison
with simultaneous ground-based DOAS observations. In addition, the
measurements are compared to model calculations taking into account the
photochemical change along the light path.
Revised: 21 Dec 2010 – Accepted: 05 Jan 2011 – Published: 24 Jan 2011
Although OClO does not participate directly in the destruction of ozone, its
accurate measurement as well as modelling is crucial to understand the
highly perturbed chlorine chemistry in the polar vortices. SCIAMACHY OClO
slant columns retrieved during spring 2005 have been quantitatively
validated by comparison with slant columns retrieved from measurements made
in Ny-Ålesund (79° N, 12° E) and Summit (73° N, 38° W) as
well qualitatively for Bremen (53° N, 9° E). Fair to good agreement is
found depending on location as well as time of year.
OClO slant column densities modelled with a set of stacked box models and
considering the light path through the atmosphere are also included in this
comparison. The model predictions differ significantly from the measured
quantities. OClO amounts are underestimated for conditions of strong
chlorine activation and at large solar zenith angles. Sensitivity studies
for several parameters in the stacked box model have been performed and it
is inferred that using the chemistry known to date, the observed OClO cannot
be adequately reproduced within the range of uncertainties given for the
various model parameters.
Citation: Oetjen, H., Wittrock, F., Richter, A., Chipperfield, M. P., Medeke, T., Sheode, N., Sinnhuber, B.-M., Sinnhuber, M., and Burrows, J. P.: Evaluation of stratospheric chlorine chemistry for the Arctic spring 2005 using modelled and measured OClO column densities, Atmos. Chem. Phys., 11, 689-703, doi:10.5194/acp-11-689-2011, 2011.