Recent advances in gravity wave analysis from long term global GPS radio occultation observations

Abstract

A previous global analysis of wave potential energy using Global Positioning System (GPS) radio occultation (RO) temperature profiles revealed a considerable intense gravity wave activity (WA) at middle latitudes near to the Andes Range. WRF (Weather Research and Forecasting) and MM5 (Mesoscale Model 5) mesoscale model results for two selected cases in the vicinity of RO lines of tangent points, confirm an intense activity near to the mountains. A wavelet analysis led us to identify principal modes with two main horizontal wavelengths, clearly corresponding to mountain waves. Different hodograph analyses evidence that inertio gravity waves (IGWs) are due to mountain forcing and not to geostrophic adjustment at jet levels, as could be expected too. One of the simulations does not show intense WA in the vicinity of the tangent points, even though that the GPS-RO temperature profile detects it. We conclude that the GPS-RO technique is not by itself reliable enough to quantify and locate accurately WA of single events, but it should be considered as a useful tool to detect the global distribution of WA. © 2009 Springer-Verlag Berlin Heidelberg.