Planetary waves in the upper stratosphere and lower mesosphere during 2009 Arctic major stratospheric warming

• Published in: Annales Geophysicae
• Main Authors: Kishore, P., Velicogna, I., Venkat Ratnam, M., Jiang, J. H, Madhavi, G. N
• Format: Article in Journal/Newspaper
• Language: English
• Published: eScholarship, University of California 2012
• Subjects: Physical Sciences and Mathematics; Meteorology and atmospheric dynamics; Middle atmosphere dynamics; empirical mode decomposition; EOS MLS; interannual variability; Antarctic mesosphere; northern-hemisphere; lower thermosphere; quasi-2-day wave; Hilbert spectrum; aura satellite; water-waves; Antarctic; Arctic; Merra; Antarc*
• Online Access: http://www.escholarship.org/uc/item/8wr0h6kz

The AURA-MLS daily mean temperatures and zonal wind from NASA-MERRA reanalysis for latitudes between 60° N and 80° N are used to investigate the planetary wave (PW) characteristics in the stratosphere and lower mesosphere during sudden stratospheric warming (SSW) (November 2008 to March 2009). Here, we used a novel method called empirical mode decomposition (EMD) to extract the PWs from the temperature data. The EMD is an interesting approach to decompose signals into locally periodic components, the intrinsic mode functions (IMFs), and will easily identify the embedded structures, even those with small amplitudes. The spectral analysis reveals prevailing planetary wave periods of ~6-day, ~8-day, ~15-day, and ~21–23-day in IMFs 1, 2, 3, and 4, respectively. Clear upward propagation of these waves (20–30 days) is observed, suggesting that sources for these oscillations are in the troposphere.