Forecast, observation and modelling of a deep stratospheric intrusion event over Europe
1Research Center for Atmospheric Physics and Climatology, Academy of Athens, Athens, Greece
2Forschungszentrum Karlsruhe, IMK-IFU, Garmisch-Partenkirchen, Germany
3Lehrstuhl für Bioklimatologie und Immissionsforschung Technische Universität München, Freising, Germany
4Atmospheric Physics, ETHZ, Zürich, Switzerland
5Cooperative Institute for Research in Environmental Sciences, University of Colorado, Boulder/NOAA Aeronomy Laboratory, Boulder, USA
6Laboratory of Climatology and Atmospheric Environment, National and Kapodistrian University of Athens, Greece
7Departement für Chemie und Biochemie, Universität Bern, Switzerland
8Paul Scherrer Institute, Villigen PSI, Switzerland
9Inst. Particle Physics, ETH Hoenggerberg, Switzerland
10Scottish Universities Environmental Research Centre, East Kilbride, U.K.
11Paul Scherrer Institute, c/o ETH Hoenggerberg, Switzerland
12Institut für Isotopenforschung und Kernphysik, Universität Wien, Austria
13Institute of Atmospheric Sciences and Climate, Bologna, Italy
14Nuclear Physics Department, Aristotle Univ. of Thessaloniki, Greece
15Royal Meteorological Institute KMI, Uccle, Belgium
16Department of Physics, National Technical University of Athens, Greece
17Deutscher Wetterdienst, Meteorologisches Observatorium Hohenpeißenberg, Germany
Abstract. A wide range of measurements was carried out in central and southeastern Europe within the framework of the EU project STACCATO (Influence of Stratosphere-Troposphere Exchange in a Changing Climate on Atmospheric Transport and Oxidation Capacity) with the principle goal to create a comprehensive data set on stratospheric air intrusions into the troposphere along a rather frequently observed pathway over central Europe from the North Sea to the Mediterranean Sea. The measurements were based on predictions by suitable quasi-operational trajectory calculations using ECMWF forecast data. A predicted deep Stratosphere to Troposphere Transport (STT) event, encountered during the STACCATO period on 20-21 June 2001, was followed by the measurements network almost from its inception. Observations provide evidence that the intrusion affected large parts of central and southeastern Europe. Especially, the ozone lidar observations on 20-21 June 2001 at Garmisch-Partenkirchen, Germany captured the evolution of two marked tongues of high ozone with the first one descending to nearly 2 km, thus providing an excellent data set for model intercomparisons and validation. In addition, for the first time to our knowledge concurrent surface measurements of the cosmogenic radionuclides 10Be and 7Be and their ratio 10Be/7Be are presented together as stratospheric tracers in a case study of a stratospheric intrusion. The ozone tracer columns calculated with the FLEXPART model were found to be in good agreement with water vapour satellite images, capturing the evolution of the observed dry streamers of stratospheric origin. Furthermore, the time-height cross section of ozone tracer simulated with FLEXPART over Garmisch-Partenkirchen captures many details of the evolution of the two observed high-ozone filaments measured with the IFU lidar, thus demonstrating the considerable progress in model simulations. Finally, the modelled ozone (operationally available since October 1999) from the ECMWF (European Centre for Medium-Range Weather Forecasts) atmospheric model is shown to be in very good agreement with the observations during this case study, which provides the first successful validation of a chemical tracer that is derived operationally from a weather forecast model. This suggests that coupling chemistry and weather forecast models may significantly improve both weather and chemical forecasts in the future.
Zanis, P., Trickl, T., Stohl, A., Wernli, H., Cooper, O., Zerefos, C., Gaeggeler, H., Schnabel, C., Tobler, L., Kubik, P. W., Priller, A., Scheel, H. E., Kanter, H. J., Cristofanelli, P., Forster, C., James, P., Gerasopoulos, E., Delcloo, A., Papayannis, A., and Claude, H.: Forecast, observation and modelling of a deep stratospheric intrusion event over Europe, Atmos. Chem. Phys., 3, 763-777, doi:10.5194/acp-3-763-2003, 2003.