Distribution of hydrogen peroxide and formaldehyde over Central Europe during the HOOVER project 1Department of Atmospheric Chemistry, Max Planck Institute for Chemistry, Mainz, Germany
11 May 2011
2Department of Chemistry, York University, Toronto, Canada
*now at: Oeschger Centre for Climate Change Research and Institute for Geography, Univ. Bern, Switzerland
**now at: Deutsches Zentrum für Luft und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany
Received: 05 November 2010 – Published in Atmos. Chem. Phys. Discuss.: 06 January 2011 Abstract. In this study we report measurements of hydrogen peroxide (H2O2),
methyl hydroperoxide* (MHP* as a proxy of MHP based on an unspecific
measurement of total organic peroxides) and formaldehyde (HCHO) from the
HOx OVer EuRope (HOOVER) project (HOx = OH+HO2).
HOOVER included two airborne field campaigns, in October 2006 and July 2007.
Measurement flights were conducted from the base of operation Hohn (Germany,
54° N, 9° E) towards the Mediterranean and to the
subpolar regions over Norway. We find negative concentration gradients with
increasing latitude throughout the troposphere for H2O2 and
CH3OOH*. In contrast, observed HCHO is almost homogeneously
distributed over central and northern Europe and is elevated over the
Mediterranean. In general, the measured gradients tend to be steepest
entering the Mediterranean region, where we also find the highest abundances
of the 3 species. Mixing ratios of these tracers generally decrease with
altitude. H2O2 and CH3OOH* show maxima above the boundary
layer at 2–5 km, being more distinct over southern than over northern Europe.
Revised: 26 April 2011 – Accepted: 28 April 2011 – Published: 11 May 2011
We also present a comparison of our data with simulations by two global
3-D-models, MATCH-MPIC and EMAC, and with the box model CAABA. The models
realistically represent altitude and latitude gradients for both HCHO and
hydroperoxides (ROOH). In contrast, the models have problems reproducing the
absolute mixing ratios, in particular of H2O2. Large uncertainties
about retention coefficients and cloud microphysical parameters suggest that
cloud scavenging might be a large source of error for the simulation of
H2O2. A sensitivity study with EMAC shows a strong influence of
cloud and precipitation scavenging on the budget of H2O2 as
simulations improve significantly with this effect switched off.
Citation: Klippel, T., Fischer, H., Bozem, H., Lawrence, M. G., Butler, T., Jöckel, P., Tost, H., Martinez, M., Harder, H., Regelin, E., Sander, R., Schiller, C. L., Stickler, A., and Lelieveld, J.: Distribution of hydrogen peroxide and formaldehyde over Central Europe during the HOOVER project, Atmos. Chem. Phys., 11, 4391-4410, doi:10.5194/acp-11-4391-2011, 2011.