Influence of the mean wind field on the separability of atmospheric perturbation spectra

The effects of Doppler shifting caused by the mean wind field on the separability of gravity wave spectra are analyzed using the gravity wave models. If the intrinsic joint vertical wave number (m) and temporal frequency (ω) spectrum is separable. Doppler effects associated with even small mean winds will destroy separability of the observed joint (m, ω_o) spectrum, particularly at high vertical wave-numbers. The effect can have a substantial impact on the measured m-spectrum especially when the observations are not sensitive to the lowest or highest observed frequencies. Data averaging or low-pass temporal filtering can result in substantial reduction of the spectrum magnitude at high m values while data prewhitening of high-pass temporal filtering can result in significant distortion of the spectrum at low m values. -from Authors