A gravity wave analysis near to the Andes Range from GPS radio occultation data and mesoscale numerical simulations: Two case studies

P. LLAMEDO; A. DE LA TORRE; P. ALEXANDER; D. LUNA; T. SCHMIDT; J. WICKERT

ADVANCES IN SPACE RESEARCH

ELSEVIER SCI LTD

Año: 2009 vol. 44 p. 494 - 500

0273-1177

Global maps of potential wave energy per unit mass, recently performed with theGlobal Positioning System (GPS) Radio Occultation (RO) technique and dierentsatellite missions (CHAMP and SAC-C since 2001, GRACE and COSMIC since2006) revealed in Argentina, at the eastern side of the highest Andes Mountains,a considerable wave activity (WA) in comparison with other extra-tropical regions.The main gravity wave (GW) sources in this natural laboratory are deep convec-tion (mainly during late Spring and Summer), topographic forcing and geostrophicadjustment. The mesoscale numerical WRF (Weather Research and Forecasting) 2.1.2 modelwas used to simulate the atmospheric parameters during two representative ROevents showing an apparent intense WA in this region. The signicance of the rela-tive position of the RO lines of sight, line of tangent points and gravity wave phasesurfaces during each event is discussed in relation with the apparent wave activitydetected. We also discuss the relative contribution of high and medium intrinsic fre-quency mountain waves regularly observed, coexisting with inertio gravity waves,their origin and propagation characteristics.