Mesospheric N 2 O enhancements as observed by MIPAS on Envisat during the polar winters in 2002?2004

International audience N 2 O abundances ranging from 0.5 to 6 ppbv were observed in the polar upper stratosphere/lower mesosphere by the MIPAS instrument on the Envisat satellite during the Arctic and Antarctic winters in the period July 2002 to March 2004. A detailed study of the observed N 2 O?CH...

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Bibliographic Details
Main Authors: Funke, B., López-Puertas, M., García-Comas, M., Stiller, G. P., Von Clarmann, T., Glatthor, N.
Other Authors: Instituto de Astrofísica de Andalucía (IAA), Consejo Superior de Investigaciones Científicas Madrid (CSIC), Forschungszentrum Karlsruhe
Format: Article in Journal/Newspaper
Language:English
Published: HAL CCSD 2008
Subjects:
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean
Atmosphere
Arctic
Antarctic
Antarc*
Online Access:https://hal.archives-ouvertes.fr/hal-00304226
https://hal.archives-ouvertes.fr/hal-00304226/document
https://hal.archives-ouvertes.fr/hal-00304226/file/acpd-8-10561-2008.pdf
Description
Summary:International audience N 2 O abundances ranging from 0.5 to 6 ppbv were observed in the polar upper stratosphere/lower mesosphere by the MIPAS instrument on the Envisat satellite during the Arctic and Antarctic winters in the period July 2002 to March 2004. A detailed study of the observed N 2 O?CH 4 correlations shows that such enhancements are of chemical rather than dynamical origin. The N 2 O enhancements observed at 58 km occurred in presence of NO x intrusions from the upper atmosphere which were related to energetic particle precipitation. Further, the inter-annual variability of mesospheric N 2 O correlates well with observed precipitating electron fluxes. The analysis of possible chemical production mechanisms shows that the major part of the observed N 2 O enhancements is most likely generated under dark conditions by the reaction of NO 2 with atomic nitrogen at altitudes around 70?75 km in the presence of energetic particle precipitation. A possible additional source of N 2 O in the middle and upper polar atmosphere is the reaction of N 2 (A 3 ? u + ), generated by precipitating electrons, with O 2 , which would lead to N 2 O production peaking at altitudes around 90?100 km. N 2 O produced by the latter mechanism could then descend to the mesosphere and upper stratosphere during polar winter.

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