Aura Microwave Limb Sounder observations of dynamics and transport during the record‐breaking 2009 Arctic stratospheric major warming

Abstract

A major stratospheric sudden warming (SSW) in January 2009 was the strongest and most prolonged on record. Aura Microwave Limb Sounder (MLS) observations are used to provide an overview of dynamics and transport during the 2009 SSW, and to compare with the intense, long‐lasting SSW in January 2006. The Arctic polar vortex split during the 2009 SSW, whereas the 2006 SSW was a vortex displacement event. Winds reversed to easterly more rapidly and reverted to westerly more slowly in 2009 than in 2006. More mixing of trace gases out of the vortex during the decay of the vortex fragments, and less before the fulfillment of major SSW criteria, was seen in 2009 than in 2006; persistent well‐defined fragments of vortex and anticyclone air were more prevalent in 2009. The 2009 SSW had a more profound impact on the lower stratosphere than any previously observed SSW, with no significant recovery of the vortex in that region. The stratopause breakdown and subsequent reformation at very high altitude, accompanied by enhanced descent into a rapidly strengthening upper stratospheric vortex, were similar in 2009 and 2006. Many differences between 2006 and 2009 appear to be related to the different character of the SSWs in the two years.

Retrieval of temperature and pressure using broadband solar occultation: SOFIE approach and results

“…Results at pressures in the range 0.1 to 0.01 mb are somewhat worse for both periods, for the February data this could be due to larger dynamic activity in this region. This period follows what appears to be one of the strongest stratospheric sudden warmings (SSW) on record (Manney et al, 2009). The high latitude stratopause reformed at approximately 80 km in early February following this SSW and remained at elevated altitudes until approximately mid-March.…”

Geomagnetic activity signatures in wintertime stratosphere wind, temperature, and wave response

“…[16] In the first part of our study, we will focus on results from analysis where data from winters during which a midwinter Sudden Stratospheric Warming (SSW) occurred [see Charlton and Polvani, 2007;Manney et al, 2009] were omitted. While this does reduce the data set somewhat, it does not affect the overall U, T, and EP patterns, but in most cases leads to an improvement of the statistical significance of the results.…”

Mesosphere-to-stratosphere descent of odd nitrogen in February–March 2009 after sudden stratospheric warming

“…Along the lines of Arnold and Robinson (2001), Lu et al (2008) also concluded that this is likely due to coupling between the mean flow and atmospheric waves. Satellite observations have shown that exceptionally strong NO x descent events occurred in 2004, 2006 and 2009 after sudden stratospheric warming events Manney et al, 2009). These events are related to reformation of the vortex following its split/displacement.…”