Gravity waves excited during a minor sudden stratospheric warming

• Published in: Atmospheric chemistry and physics 2018-09, Vol.18 (17), p.12915-12931
• Main Authors: Dörnbrack, Andreas, Gisinger, Sonja, Kaifler, Natalie, Portele, Tanja Christina, Bramberger, Martina, Rapp, Markus, Gerding, Michael, Söder, Jens, Žagar, Nedjeljka, Jelić, Damjan
• Format: Article
• Language: English
• Subjects: Aerodynamics; Airports; Gravitational waves; Gravity; Gravity waves; Gravity waves (Meteorology); Inertia; Inertia gravity waves; Internal gravity waves; Internal waves; Lower stratosphere; Natural history; Ozone; Polar environments; Polar vortex; Propagation modes; Radiosondes; Stratosphere; Stratospheric gravity waves; Stratospheric sudden warmings; Stratospheric warming; Temperature; Temperature fluctuations; Two dimensional analysis; Upper stratosphere; Wave generation; Wave packets; Wave propagation; Wavelet analysis; Weather forecasting; Winter
• ISSN: 1680-7324; 1680-7316; 1680-7324
• DOI: 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.