View abstract

Shepherd Marianna

Institute:
Centre for Research in Earth and Space Sceince, York University.
Toronto, Canada

INVESTIGATION OF MAJOR STRATOSPHERIC WARMING EFFECTS ON ATMOSPHERIC COUPLING AT HIGH LATITUDES USING THE EXTENDED CANADIAN MIDDLE ATMOSPHERE MODEL

Authors: M. G. Shepherd, S. R. Beagley, Y.M. Cho, V. Fomichev, G.G. Shepherd, Centre for Research in Earth and Space Science, York University, Toronto, Ontario

The study examines the response of the mesosphere/lower thermosphere to the major stratospheric warming (SSW) event from January 2009, as seen in the OH and O2 (0,1) Atmospheric band airglow observations nominally at 87 km and 94 km, respectively by a SATI (Spectral Airglow Temperature Imager) instrument installed at the Polar Environment Atmospheric Research Laboratory (PEARL) at Eureka (80°N, 86°W) as part of the Canadian Network for the Detection of Atmospheric Change. At the time of the SSW the airglow emissions and the derived rotational temperatures appear depleted and decreased, respectively followed by an enhancement of the airglow emission rates during the SSW recovery phase, while the temperatures returned to their pre-event state. An empirical relationship between OH airglow peak altitude determined by SABER and SATI integrated emission rates allowed perturbed OH and O2 (0,1) airglow altitudes to be assigned to the SATI observations. From these the O volume mixing ratio (VMR), corresponding to the observed OH and O2 (0,1) airglow emission rates were modeled. Atomic oxygen depletion by a factor of ~5 was observed during the SSW and lasted for about 5 days. During the SSW recovery phase the O VMR giving rise to the observed O2 (0,1) airglow emission rates increased by a factor of 3.5 from its pre-SSW level and 17 times from that observed during the peak of the SSW. The observed response of the MLT region to the major stratospheric warming is further examined employing temperature and wind fields, as well as NO and O constituents from the extended Canadian Middle Atmosphere Model (CMAM) at high latitudes from 10 to 220 km height. Temperature and NO observations by the COSMIC/Formosat-3, MLS-Aura and TIMED/SABER satellite experiments are also considered in this study and the results are discussed.
airglow, stratospheric warming, temperature, coupling, modeling

All abstracts in one page