Peroxy radical partitioning during the AMMA radical intercomparison exercise 1Institute of Environmental Physics, University of Bremen, Bremen, Germany
2School of Chemistry, University of Leeds, Leeds, UK
3School of Earth and Environment, University of Leeds, Leeds, UK
4Department of Chemistry, University of Leicester, Leicester, UK
5School of Environmental Sciences, University of East Anglia, Norwich, UK
6Institute of Atmospheric Physics, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Oberpfaffenhofen, Germany
7National Centre for Atmospheric Science, University of Leeds, Leeds, UK
8Department of Meteorology, University of Reading, Reading, UK
*now at: School of Engineering and Applied Science, Harvard University, Cambridge, USA
Received: 11 February 2010 – Published in Atmos. Chem. Phys. Discuss.: 01 April 2010 Abstract. Peroxy radicals were measured onboard two scientific aircrafts during the
AMMA (African Monsoon Multidisciplinary Analysis) campaign in summer 2006.
This paper reports results from the flight on 16 August 2006 during which
measurements of HO2 by laser induced fluorescence spectroscopy at low
pressure (LIF-FAGE) and total peroxy radicals
(RO2* = HO2+ΣRO2, R = organic chain) by two
similar instruments based on the peroxy radical chemical amplification
(PeRCA) technique were subject of a blind intercomparison. The German
DLR-Falcon and the British FAAM-BAe-146 flew wing tip to wing tip for about
30 min making concurrent measurements on 2 horizontal level runs at 697 and
485 hPa over the same geographical area in Burkina Faso. A full set of
supporting measurements comprising photolysis frequencies, and relevant trace
gases like CO, NO, NO2, NOy, O3 and a wider range of VOCs
were collected simultaneously.
Revised: 08 October 2010 – Accepted: 04 November 2010 – Published: 11 November 2010
Results are discussed on the basis of the characteristics and limitations of
the different instruments used. Generally, no data bias are identified and
the RO2* data available agree quite reasonably within the
instrumental errors. The [RO2*]/[HO2] ratios, which vary
between 1:1 and 3:1, as well as the peroxy radical variability, concur
with variations in photolysis rates and in other potential radical
precursors. Model results provide additional information about dominant
radical formation and loss processes.
Citation: Andrés-Hernández, M. D., Stone, D., Brookes, D. M., Commane, R., Reeves, C. E., Huntrieser, H., Heard, D. E., Monks, P. S., Burrows, J. P., Schlager, H., Kartal, D., Evans, M. J., Floquet, C. F. A., Ingham, T., Methven, J., and Parker, A. E.: Peroxy radical partitioning during the AMMA radical intercomparison exercise, Atmos. Chem. Phys., 10, 10621-10638, doi:10.5194/acp-10-10621-2010, 2010.