Are we Observing Mountain Waves Above the Andes Range from GPS Occultation Profiles?

DE LA TORRE, A.; ALEXANDER, P.; MENÉNDEZ, C.

Atmosphere and Climate: Studies by Occultation Methods

Springer

Año: 2006; p. 243 - 252

GPS radio occultation temperature profiles retrieved from SAC-C andCHAMP exhibit a significant wave activity in the troposphere and lower stratosphereat midlatitudes (30◦S to 40◦S) above the Andes Range. Large amplitudestructures, with long vertical wavelength, have been repeatedly reported in this region,as detected from other experimental devices and attributed to mountain waves.The possibility to associate the observed enhancements in wave activity to mountainforcing, or instead, to other significant sources in the region considered is discussed.The generation in the vicinity to a permanent jet situated above the mountains ofinertio gravity waves by geostrophic adjustment, with longer horizontal and perhapsshorter vertical wavelengths than those expected from mountain waves, seems to bethe main source. These waves could be more easily detected from GPS profiles thanmountain waves. As it is known, inertio gravity waves are the means by which massand momentum are redistributed so as to ultimately achieve geostrophic balancefrom an initially unbalanced state.