Articles | Volume 13, issue 21
Atmos. Chem. Phys., 13, 10703–10720, 2013

Special issue: The Modular Earth Submodel System (MESSy) (ACP/GMD inter-journal...

Atmos. Chem. Phys., 13, 10703–10720, 2013

Research article 04 Nov 2013

Research article | 04 Nov 2013

HOx measurements in the summertime upper troposphere over Europe: a comparison of observations to a box model and a 3-D model

E. Regelin1, H. Harder1, M. Martinez1, D. Kubistin1,*, C. Tatum Ernest1, H. Bozem1, T. Klippel1, Z. Hosaynali-Beygi1, H. Fischer1, R. Sander1, P. Jöckel1,***, R. Königstedt1, and J. Lelieveld1 E. Regelin et al.
  • 1Department of Atmospheric Chemistry, Max Planck Institute for Chemistry, Mainz, Germany
  • *now at: University of Wollongong, School of Chemistry, Wollonong, NSW, Australia
  • **now at: Institute for Atmospheric Physics, University Mainz, Mainz, Germany
  • ***now at: Deutsches Zentrum für Luft und Raumfahrt (DLR), Institut für Physik der Atmosphäre, Oberpfaffenhofen, Germany

Abstract. In situ airborne measurements of OH and HO2 with the HORUS (HydrOxyl Radical measurement Unit based on fluorescence Spectroscopy) instrument were performed in the summertime upper troposphere across Europe during the HOOVER 2 (HOx OVer EuRope) campaign in July 2007. Complementary measurements of trace gas species and photolysis frequencies were conducted to obtain a broad data set, which has been used to quantify the significant HOx sources and sinks. In this study we compare the in situ measurement of OH and HO2 with simulated mixing ratios from the constrained box model CAABA/MECCA (Chemistry As A Box Model Application/Module Efficiently Calculating the Chemistry of the Atmosphere), and the global circulation model EMAC (ECHAM5/MESSy Atmospheric Chemistry Model). The constrained box model reproduces the observed OH and HO2 mixing ratios with better agreement (obs/mod median 98% OH, 96% HO2) than the global model (median 76% OH, 59% HO2). The observations and the computed HOx sources and sinks are used to identify deviations between the models and their impacts on the calculated HOx budget.

Final-revised paper