Remote-sensing measurements in the polar vortex: Comparison to in situ observations and implications for the simultaneous retrievals and analysis of the NO 2 and OClO species

• Published in: Journal of Geophysical Research
• Main Authors: Berthet, Gwenaël, Renard, Jean-Baptiste, Catoire, Valéry, Chartier, Michel, Robert, Claude, Huret, Nathalie, Coquelet, F., Bourgeois, Q., Rivière, Emmanuel D., Barret, Brice, Lefèvre, Franck, Hauchecorne, Alain
• Other Authors: Laboratoire de physique et chimie de l'environnement (LPCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Groupe de spectrométrie moléculaire et atmosphérique (GSMA), Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'aérologie (LAERO), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales Toulouse (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France-Centre National de la Recherche Scientifique (CNRS), Service d'aéronomie (SA), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2007
• Subjects: vortex; stratosphere; remote-sensing measurements; [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; Arctic
• Online Access: https://hal.science/hal-00561485; https://hal.science/hal-00561485/document; https://hal.science/hal-00561485/file/jgrd13958.pdf; https://doi.org/10.1029/2007JD008699

International audience Nighttime remote-sensing balloon observations conducted by the SALOMON instrument in the arctic polar vortex in January 2006 reveal high amounts of stratospheric NO 2 in the lower stratosphere similarly to previously published profiles. NO 2 concentration enhancements are also present in the vertical profiles observed by the GOMOS instrument on board the Envisat satellite and obtained coincidently to the balloon measurements. Such quantities are not present in in situ observations obtained by the SPIRALE instrument in similar geophysical conditions. While OClO amounts are acceptably reproduced by Chemistry Transport Model (CTM) calculations, NO 2 simulated values are well below the observed quantities. The examination of the slant column densities of NO 2 obtained at float altitude highlights unexpected strong enhancements with respect to the elevation angle and displacement of the balloon. It is shown that these fluctuations result from NO 2 spatial inhomogeneities located above the balloon float altitude. Potential vorticity maps reveal the presence of midlatitude NO 2 -rich air in the upper stratosphere or lower mesosphere as a result of the perturbed dynamical situation of the vortex. The presence of spatial inhomogeneities crossed by the lines of sight leads to artificial high concentration values of NO 2 in the vertical profile retrieved from the slant column densities assuming spatial homogeneity. A direct implication is that the differences previously observed between measurements of NO 2 and OClO and model results are probably mostly due to the improper inversion of NO 2 in the presence of perturbed dynamical conditions or when mesospheric NO x production events occur. The dynamical situation will have to be systematically analyzed in future studies involving remote-sensing observations.