Gravity wave analysis in Mendoza (Argentina), from GPS radio occultation data and MM5 simulations

A. DE LA TORRE (1), P. ALEXANDER, P. LLAMEDO SORIA,, T. SCHMIDT, J. WICKERT

Viena, Austria

Congreso; EGU 2007; 2007

EGU

The Mendoza region (Argentina) is by itself very attractive for wave analysis studies, as far as the main sources of gravity waves identified in the atmosphere take place there: orographic forcing, deep convection and geostrophic adjustment. From GPS radio occultation (RO) T data retrieved with CHAMP satellite during high wave activity events near to the Andes Mountains, a comparison with the corresponding MM5 simulations was performed. A good agreement was found along the oblique line of RO tangent points (LTP). The simulated wave structures detected at different pressure levels through wavelet analysis explains the particular intensity observed during the RO events. Different band-pass filters were applied, in order to understand main patterns that are clearly observed. One of these is of orographic origin and the other, with longer horizontal wavelength, may be orographic or instead, due to geostrophic adjustment processes at jet heights, after the perturbation introduced by the systematic presence of mountain waves during both events. From phase displacements observed at different latitudes and altitudes during the simulations, vertical wavelengths may be inferred, besides the identification made of the horizontal structures.