Energy Flux and Wavelet Diagnostics of Secondary Mountain Waves

In recent years, aircraft data from mountain waves have been primarily analyzed using velocity and temperature power spectrum and momentum flux estimation. Herein it is argued that energy flux wavelets (i.e., pressure–velocity wavelet cross-spectra) provide a more powerful tool for locating and classifying different types of mountain waves. In the first part of the paper, pressure–velocity cross-spectra using various linear mountain-wave solutions are shown to be capable of disentangling collocated waves with different propagation directions and wavelength. A field of group velocity vectors can also be determined. In the second part, the energy flux wavelet technique is applied to five cases of mountain waves entering the stratosphere from the Terrain-Induced Rotor Experiment (T-REX) in 2006. Perturbation pressure along the flight track is determined using aircraft static pressure corrected hydrostatically with GPS altitude. In four of the cases, collocated long up-propagating and short down-prop...