Analysis of the spatial distribution of the unusual NO 2 enhancements in the Arctic polar upper stratosphere and mesosphere observed by GOMOS-Envisat on January-March 2004

• Published in: Journal of Geophysical Research: Space Physics
• Main Authors: Renard, Jean-Baptiste, Bekki, Slimane, Blelly, Pierre-Louis, Bourgeois, Quentin, Berthet, Gwenaël, 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), STRATO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), 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)-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), Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-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)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2009
• Subjects: [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; Antarc*; Antarctica
• Online Access: https://hal.science/hal-00414776; https://hal.science/hal-00414776/document; https://hal.science/hal-00414776/file/Renard_et_al-2009-Journal_of_Geophysical_Research__Space_Physics_%281978_2012%29.pdf; https://doi.org/10.1029/2009JA014174

International audience Anomalously enhanced NO 2 concentrations are sometimes observed in the polar winter upper atmosphere. The enhancements over Antarctica from May to August 2003 were probably due to auroral electron precipitation, producing high amounts of NO in the upper mesosphere that were converted to NO 2 during downward transport to the stratosphere. Another enhancement was detected in the Arctic middle stratosphere in October–November 2003, due this time to energetic solar proton precipitation. This enhancement was quickly followed by a new Arctic NO 2 enhancement produced by auroral electrons in November 2003. Finally, a last enhancement was detected in the lower mesosphere from January to April 2004. Although it was proposed that this enhancement could also be due to auroral electrons, uncertainties remained concerning the absolute value of the NO 2 enhancement and its spatial coverage. We propose here a new analysis of the Global Ozone Monitoring by Occultation of Stars (GOMOS) nighttime measurements of the NO 2 enhancements. Instead of using daily zonally averaged data as done previously, we consider only the profiles containing the maximum values of the NO 2 enhancement. Unlike all the previous enhancements, the NO 2 content of the January 2004 appears to be longitudinally and latitudinally dependent inside the polar circle. The enhancement starts on 17 January 2004, with mixing ratios of up to a ppmv at altitudes above 60 km on 21 January. The enhancement looks like a “hot spot” above the polar cap. Then the enhancement spreads while it propagates downward into the stratosphere. It is accompanied by perfectly coincident strong ozone depletion; in particular, ozone is almost totally destroyed in mid-February at about 50 km. The vertical extent and horizontal spread of this NO 2 enhancement strongly differ from the November 2003 enhancement attributed to auroral electron precipitation. The possible origins of this unusual pattern are discussed.