Ozone loss in the 2002-2003 Arctic vortex deduced from the assimilation of ODIN/SMR O3 and N2O measurements : N2O as a dynamical tracer

• Published in: Quarterly Journal of the Royal Meteorological Society
• Main Authors: Elamraoui, L., Peuch, V.-H., Ricaud, P., Massart, S., Semane, N., Teyssèdre, H., Cariolle, D., Karcher, F.
• Other Authors: Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'aérologie (LAERO), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales Toulouse (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), CERFACS, Centre Nationale de Recherches Météorologiques
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2008
• Subjects: Chemical data assimilation; diabatic descent; chemical ozone loss; Assimilation des données chimiques; Descente diabatique; Perte d'ozone; Modèle de transport chimique; [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology; Arctic
• Online Access: https://hal-meteofrance.archives-ouvertes.fr/meteo-00365825; https://doi.org/10.1002/qj.191

International audience In this paper we investigate the evolution of the northern polar vortex during the winter 2002–2003 in the lower stratosphere by using assimilated fields of ozone (O3) and nitrous oxide (N2O). Both O3 and N2O used in this study are obtained from the Sub-Millimetre Radiometer (SMR) aboard the Odin satellite and are assimilated into the global three-dimensional chemistry transport model of M´et´eo-France, MOCAGE. O3 is assimilated into the ‘full' model including both advection and chemistry whereas N2O is only assimilated with advection since it is characterized by good chemical stability in the lower stratosphere. We show the ability of the assimilated N2O field to localize the edge of the polar vortex. The results are compared to the use of the maximum gradient of modified potential vorticity as a vortex edge criterion. The O3 assimilated field serves to evaluate the ozone evolution and to deduce the ozone depletion inside the vortex. The chemical ozone loss is estimated using the vortex-average technique. The N2O assimilated field is also used to substract out the effect of subsidence in order to extract the actual chemical ozone loss. Results show that the chemical ozone loss is 1.1 ± 0.3 ppmv on the 25 ppbv N2O level between mid-November and mid-January, and 0.9 ± 0.2 ppmv on the 50 ppbv N2O level between mid-November and the end of January. A linear fit over the same periods gives a chemical ozone loss rate of ∼18 ppbv day−1 and ∼9.3 ppbv day−1 on the 25 ppbv and 50 ppbv N2O levels, respectively. The vortex-averaged ozone loss profile from the O3 assimilated field shows a maximum of 0.98 ppmv at 475 K. Comparisons to other results reported by different authors using different techniques and different observations give satisfactory results.