Recent advances in global wave activity analysis from long-term GPS RO data

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

Graz

Congreso; Occultations for Probing Atmosphere and Climate 3; 2007

A previous global analysis of wave potential energy using Global PositioningSystem (GPS) radio occultation (RO) temperature profiles revealed a considerableintense gravity wave activity (WA) at middle latitudes near to the AndesRange. WRF (Weather Research and Forecasting) and MM5 (Mesoscale Model 5)mesoscale model results for two selected cases in the vicinity of RO lines of tangentpoints, confirm an intense activity near to the mountains. A wavelet analysis ledus to identify principal modes with two main horizontal wavelengths, clearly correspondingto mountain waves. Different hodograph analyses evidence that inertiogravity waves (IGWs) are due to mountain forcing and not to geostrophic adjustmentat jet levels, as could be expected too. One of the simulations does not showintense WA in the vicinity of the tangent points, even though that the GPS-RO temperatureprofile detects it. We conclude that the GPS-RO technique is not by itselfreliable enough to quantify and locate accurately WA of single events, but it shouldbe considered as a useful tool to detect the global distribution of WA.