Investigation of Arctic ozone depletion sampled over midlatitudes during the Egrett campaign of spring/summer 2000 D. E. M. Ross1,*, J. A. Pyle1,2, N. R. P. Harris1,3, J. D. McIntyre1, G. A. Millard1, A. D. Robinson1, and R. Busen4 1Centre for Atmospheric Sciences, Department of Chemistry, University of Cambridge, Cambridge, UK 2NCAS-ACMSU, Department of Chemistry, University of Cambridge, Cambridge, UK 3European Ozone Research Coordinating Unit, University of Cambridge, Cambridge, UK 4Deutsches Zentrum für Luft- und Raumfahrt (DLR), Oberpfaffenhofen, Germany *now at: JMP Consulting, London, UK
Abstract. A unique halocarbon dataset has been obtained using the Australian high
altitude research aircraft, the Grob G520T Egrett, during May-June 2000 with
GC instrument (DIRAC), which has been previously deployed on balloon
platforms. The halocarbon data generally shows a good anticorrelation with
ozone data obtained simultaneously from commercial sensors. On 5 June
2000, at 380K, the Egrett entered a high latitude tongue of air over the
U.K. CFC-11 and O3 data obtained on the flight show evidence of this
feature. The dataset has been used, in conjunction with a 3D chemical
transport model, to infer ozone depletion encountered in the midlatitude
lower stratosphere during the flight. We calculate that ozone is depleted by
20% relative to its winter value in the higher latitude airmass. A suite
of ozone loss tracers in the model have been used to track ozone depletion
according to location relative to the vortex and chemical cycle responsible.
The model, initialised on 9 December, indicates that 50% of the
total chemical ozone destruction encountered in June in the middle latitudes
occurred in the 90-70°N equivalent latitude band and that 70%
was due to halogen chemistry.
Citation: Ross, D. E. M., Pyle, J. A., Harris, N. R. P., McIntyre, J. D., Millard, G. A., Robinson, A. D., and Busen, R.: Investigation of Arctic ozone depletion sampled over midlatitudes during the Egrett campaign of spring/summer 2000, Atmos. Chem. Phys., 4, 1407-1417, doi:10.5194/acp-4-1407-2004, 2004.