Overall air mass characterisation in the free troposphere during MINOS: NOy - partitioning,
comparison with previous campaigns and model simulations
Helmut Ziereis1, Jörg Heland1, Hans Schlager1,
Christine Hauser1, Paul Stock1, Anke Roiger1,
Marian de Reus2, Rupert Holzinger2 and Geert-Jan Roelofs3
1Deutsches Zentrum für Luft- und Raumfahrt (DLR), Oberpfaffenhofen, Germany
2Max-Planck-Institut für Chemie, Mainz, Germany
3Institute for Marine and Atmospheric Research, Untrecht University, the Netherlands
In August 2001 focussed aircraft measurements were performed out of Heraklion airport
on Crete within the MINOS (Mediterranean Intensive Oxidant Study) project. In total
14 flights were performed with the DLR research aircraft Falcon. In this study in situ
measurements of NO, NOy, PAN, O3 and CO are discussed with respect to air mass
characterisation by ECHAM 4 model simulations. This tracer analysis revealed that the
air masses encountered during the MINOS aircraft missions were predominantly governed
by four different source regimes: Indian boundary layer, air of stratospheric origin,
European boundary layer air and lower tropospheric air from the North Atlantic region.
Measured NO, PAN and NOy and deduced NOx, assuming simple photo-stationary state, are
used to study the partitioning of reactive nitrogen species. The NOy partitioning is
analysed with respect to air mass origin, altitude and air mass age.
The data set acquired during the aircraft measurements of MINOS is compared to previous
aircraft campaign (e.g. EXPORT 2000, INCA 2000, POLINAT 2 1997, SIL 1996) performed in
recent years over central Europe and the North Atlantic flight corridor. This comparison
helps to develop an understanding of the contribution of different sources to the nitrogen
oxides budget over Europe.