Jena 2013 – scientific programme

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EP: Fachverband Extraterrestrische Physik

EP 6: Astrobiologie/Erdnaher Weltraum

EP 6.6: Invited Talk

Wednesday, February 27, 2013, 15:30–16:00, HS 9

Atmospheric coupling processes by internal gravity waves — •Andreas Dörnbrack — Institut für Physik der Atmosphäre, DLR Oberpfaffenhofen, Germany

Internal gravity waves exist by virtue of the stable density stratification of the atmosphere. Disturbances to a balanced state, e.g. by the flow past a mountain, excite internal gravity waves with a variety of spatial and temporal scales. Horizontal wavelengths range from kilometers to thousands of kilometers, and periods range from the Brunt-Väisälä period (approximately ten minutes in the troposphere) to the inertial period, which is infinite at the Equator and 12 hours at the poles.

Gravity waves occur at all altitudes and are important for several reasons: They transport energy and momentum from one region of the atmosphere to another; they initiate and modulate convection and subsequent hydrological processes; they disturb the smooth, balanced state through injection of energy and momentum into the flow; and, when the waves break, turbulence hazardous to aviation is generated and chemical species are mixed. These wave breaking processes occur globally and significantly affect climate of the mesosphere and stratosphere. Gravity waves may also affect space weather by seeding ionospheric irregularities.

The presentation will overview recent attempts to answer the outstanding questions in the gravity wave excitation mechanism, source distribution and variability, especially, the wave impact in the lower, middle and upper atmosphere.