A gravity wave analysis in Mendoza (Argentina), as detected from GPS radio occultation data and mesoscale numerical simulation

A. DE LA TORRE1, P. ALEXANDER1, P. LLAMEDO1, D. LUNA1, T. SCHMIDT2 AND J. WICKERT2

Bologna, Italia

Congreso; SPARC; 2008

Global maps of potential wave energy per unit mass, recently performed with the GPS (Global Positioning System) Radio Occultation (RO)technique and different satellite missions (CHAMP since 2001, GRACE since 2006 and COSMIC since 2006) revealed in Argentina, at the eastern side of the highest Andes Mountains, a considerable wave activity in comparison with other extra-tropical regions. The main gravity wave sources in this natural laboratory are deep convection (mainly during late Spring and Summer), topographic forcing (during stable conditions) and geostrophic adjustment (expected but not clearly identified up to now during highly variable tropospheric jet conditions). The mesoscale numerical model WRF (Weather Research and Forecasting model) was used to simulate the atmospheric parameters during representative RO events showing an apparent intense WA in this region. The significance of the relative position of the RO lines of sight, line of tangent points and gravity wave phase surfaces during each event is discussed in relation with the apparent wave activity detected. We also discuss the relative contribution of high and medium intrinsic frequency mountain waves regularly observed, coexisting with inertio gravity waves, their origin and propagation characteristics. Random and systematic errors associated to the RO technique are estimated.