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Polar Vortex Evolution during the 2002 Antarctic Major Warming as Observed by the Odin Satellite

P. Ricaud ; F. Lefévre ; G. Berthet ; Donal P. Murtagh (Institutionen för radio- och rymdvetenskap, Global miljömätteknik) ; E.J. Llewellyn ; G. Mégie ; E. Kyrölä ; W. Leppelmeier ; Samuel Brohede (Institutionen för radio- och rymdvetenskap, Global miljömätteknik) ; Patrick Eriksson ; Nicolas Lautié (Institutionen för radio- och rymdvetenskap, Global miljömätteknik) ; Michael Olberg (Institutionen för radio- och rymdvetenskap, Nationella anläggningen för radioastronomi) ; Joachim Urban (Institutionen för radio- och rymdvetenskap, Global miljömätteknik) ; al et
Journal of Geophysical Research - Atmospheres (0148-0227). Vol. 110 (2005), D5,
[Artikel, refereegranskad vetenskaplig]

In September 2002 the Antarctic polar vortex split in two under the influence of a sudden warming. During this event, the Odin satellite was able to measure both ozone (O(3)) and chlorine monoxide (ClO), a key constituent responsible for the so-called "ozone hole'', together with nitrous oxide (N(2)O), a dynamical tracer, and nitric acid (HNO(3)) and nitrogen dioxide (NO(2)), tracers of denitrification. The submillimeter radiometer (SMR) microwave instrument and the Optical Spectrograph and Infrared Imager System (OSIRIS) UV-visible light spectrometer (VIS) and IR instrument on board Odin have sounded the polar vortex during three different periods: before (19-20 September), during (24-25 September), and after (1-2 and 4-5 October) the vortex split. Odin observations coupled with the Reactive Processes Ruling the Ozone Budget in the Stratosphere (REPROBUS) chemical transport model at and above 500 K isentropic surfaces (heights above 18 km) reveal that on 19-20 September the Antarctic vortex was dynamically stable and chemically nominal: denitrified, with a nearly complete chlorine activation, and a 70% O(3) loss at 500 K. On 25-26 September the unusual morphology of the vortex is monitored by the N(2)O observations. The measured ClO decay is consistent with other observations performed in 2002 and in the past. The vortex split episode is followed by a nearly complete deactivation of the ClO radicals on 1-2 October, leading to the end of the chemical O(3) loss, while HNO(3) and NO(2) fields start increasing. This acceleration of the chlorine deactivation results from the warming of the Antarctic vortex in 2002, putting an early end to the polar stratospheric cloud season. The model simulation suggests that the vortex elongation toward regions of strong solar irradiance also favored the rapid reformation of ClONO(2). The observed dynamical and chemical evolution of the 2002 polar vortex is qualitatively well reproduced by REPROBUS. Quantitative differences are mainly attributable to the too weak amounts of HNO(3) in the model, which do not produce enough NO(2) in presence of sunlight to deactivate chlorine as fast as observed by Odin.



Denna post skapades 2006-11-13. Senast ändrad 2014-09-02.
CPL Pubid: 4026

 

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Institutioner (Chalmers)

Institutionen för radio- och rymdvetenskap, Global miljömätteknik (2005-2008)
Institutionen för radio- och rymdvetenskap, Nationella anläggningen för radioastronomi (2005-2010)

Ämnesområden

Miljöteknik

Chalmers infrastruktur