Gravity waves excited during a minor sudden stratospheric warming

• Published in: Atmospheric Chemistry and Physics
• Main Authors: Dörnbrack, Andreas, Gisinger, Sonja, Kaifler, Natalie, Portele, Tanja, Bramberger, Martina, Rapp, Markus, Gerding, Michael, Söder, Jens, Zagar, Nedjeljka, Jelic, Damjan
• Format: Article in Journal/Newspaper
• Language: German
• Published: Copernicus Publications 2018
• Subjects: Verkehrsmeteorologie; Lidar; Institut für Physik der Atmosphäre; Arctic; Kiruna; Kiruna Airport
• Online Access: https://elib.dlr.de/121768/; https://doi.org/10.5194/acp-18-12915-2018

An exceptionally deep upper-air sounding launched from Kiruna airport (67.82◦ N, 20.33◦ E) on 30 January 2016 stimulated the current investigation of internal gravity waves excited during a minor sudden stratospheric warming (SSW) in the Arctic winter 2015/16. The analysis of the radiosonde profile revealed large kinetic and potential energies in the upper stratosphere without any simultaneous enhancement of upper tropospheric and lower stratospheric values. Upward-propagating inertia-gravity waves in the upper stratosphere and downward-propagating modes in the lower stratosphere indicated a region of gravity wave Generation in the stratosphere. Two-dimensional wavelet analysis was applied to vertical time series of temperature fluctuations in order to determine the vertical propagation direction of the stratospheric gravity waves in 1-hourly high-resolution meteorological analyses and short-term forecasts. The separation of upward- and downward-propagating waves provided further evidence for a stratospheric source of gravity waves. The scale-dependent decomposition of the flow into a balanced component and inertia-gravity waves showed that coherent wave packets preferentially occurred at the inner edge of the Arctic polar vortex where a sub-vortex formed during the minor SSW.