Wavelet analysis on transient behavior of wind fluctuations observed by MST radar

Abstract

Wind fluctuations observed by the MST radar technique often show complicated temporal behavior. Waves with different periods may occur at different times. Conventional fast Fourier transform (FFT) analysis will not be able to follow the temporal evolution of the wave spectrum. Multiscale, multiresolution wavelet analysis proposed in this paper is quite useful to study this transient behavior of the waves. A complex Gabor wavelet with a few cycles of monochromatic waves is chosen as the wavelet base, and this choice leads to successful results for gravity‐wave like wind disturbances observed by MST radar in the troposphere. Possible interpretations in terms of nonlinear wave‐wave or wave‐mean flow interactions are proposed.

A review of Mesosphere–Stratosphere–Troposphere (MST) radar developments and studies, circa 1997–2008

“…Weber and Wuertz (1991) developed specialist quality-control software which performs well at removing outliers. Pancheva et al (2004) used wavelet analysis for studies of planetary waves and tides, and Chen et al (1995) did likewise for shorter-scale periodicities. Stockwell et al (1996) introduced the S-transform, which performed similar functions to wavelet analysis, but had advantages in the preservation of phase information.…”

Wavelet analysis of stratospheric gravity wave packets over Macquarie Island: 1. Wave parameters

“…While wavelet analysis has been applied to wind and temperature fluctuations in the atmosphere previously [Sato and Yamada, 1994;Chen et al, 1995;$himomai et al, 1996], these studies concentrated mainly on the changes of the wavelet spectrum with time or height and less on the packet structure of the gravity wave field. section 2 gives a short definition of the wavelet transform and describes its application to the extraction of wave packets and their characteristics from radiosonde data.…”

Application of wavelet transformation to determine wavelengths and phase velocities of gravity waves observed by lidar measurements

“…The wavelet technique is applied to wind and temperature fluctuations to study mainly the change of the wavelet spectra with time and altitude (Sato and Yamada, 1994;Chen et al, 1995;Shimomai et al, 1996). In order to find out isolated wave packets in zonal and meridional winds as well as in temperature perturbations of vertical balloon sounding profiles, Zink and Vincent (2001) used wavelet transform based on the mother Morlet wavelet.…”