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PhD Defense

Julien Marty (LATMOS)

Title : Ondes de gravité atmosphériques observées par un réseau mondial de microbarographes

Date and time : The 12-10-2010 at 14h00

Type : thèse

Université qui délivre le diplôme :

Location : Université Pierre et Marie Curie (4 Place Jussieu, 75005 Paris) dans l’amphithéâtre n°25 (derrière la tour 25)
Members of jury :

M. Philippe Blanc-Benon, LMFA, Lyon (rapporteur)
M. Jacques Parent du Châtelet, Météo-France, Trappes (rapporteur)
M. François Ravetta, LATMOS/UPMC, Paris (examinateur)
M. Lars Ceranna, BGR, Hanovre, Allemagne (examinateur)
M. Läslo Evers, KNMI, De Bilt, Pays-Bas (examinateur)
M. Francis Dalaudier, LATMOS, Paris (directeur)
M. Elisabeth Blanc, CEA, Bruyères le Châtel (co-directrice)

Summary :

The Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) manages an international network of forty-two operational infrasound stations recording the pressure fluctuations produced at the ground surface by infrasonic waves. This thesis demonstrates that most of these stations also accurately detect the pressure fluctuations in the entire gravity wave band. This work includes carrying out and analyzing several metrological laboratory experiments and a field campaign (M2008) in Mongolia in 2008. The layout of the experiments as well as the interpretation of their results gave rise to the development of a new linear spectral numerical model able to simulate the generation and propagation of gravity waves. This model was used to quantify the gravity waves produced by the atmospheric cooling that occurs during solar eclipses. The pressure fluctuations expected at ground level were estimated and compared to the data recorded during the 1 August 2008 solar eclipse by the CTBTO and M2008 stations. A detailed data analysis reveals two waves with similar time-frequency characteristics to those simulated for a stratospheric and tropospheric cooling. This constitutes, to our knowledge, a unique result. The validation of worldwide and pluriannual pressure measurements in the entire gravity wave band allowed the statistical study of gravity wave spectra and atmospheric tides.

Contact :
ju.marty @ ymail.com
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