WAVELET ANALYSIS ON TRANSIENT-BEHAVIOR OF WIND FLUCTUATIONS OBSERVED BY MST RADAR

Wind fluctuations observed by the MST radar technique often show compl icated temporal behavior. Waves with different periods may occur at di fferent times. Conventional fast Fourier transform (FFT) analysis will not be able to follow the temporal evolution of the wave spectrum. Mu ltiscale, multiresolution wavelet analysis proposed in this paper is q uite useful to study this transient behavior of the waves. A complex G abor 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.