Proceedings with Extended Abstracts (single PDF file) - Radio ...

( 5 frames). The standard deviation is plotted over the mean profile. The result shows that theconsistency in estimation and low variance through multitaper spectral estimation than thatFigure 2 Mean Doppler with standard deviation obtained through (a1) Multitaper order-3 (a2) Rectangular windowfor west beam on 10May 2002of conventional method. Figure 3a and 3b shows the SNR plot of Doppler profile withmultitaper (solid line) and rectangular window (dot line) for west and Zenith beamrespectively. The multitaper based spectral analysis method gives higher SNR of the order of1- 4dB than that of rectangular window based method. This is due to the fact that in themultitaper spectral analysis noise fluctuation are reduced and there by enhanced SNR.Figure-3 SNR profiles obtained through multitaper and rectangular window on 10 May 2002 (a) West beam (b)Zenith-X beam.Atmospheric signals are highly contaminated with noise and are often difficult todetect the signal from the background noise. Since multitaper spectral estimation reducesvariances of noise the method yield better estimates during such environment. Figure 4a and4b shows the power spectrum plot of a weak region between 17.55 to 18.30 Km ofatmosphere obtained through multitaper and rectangular window method respectively. It isclear from the plots that the echoes are well defined in multitaper spectral estimate than thatof other method. The ambiguity in identifying the echoes is very less in the case multitapermethod. The result also shows that the spectral peak and the valley point (area under thespectrum) are easy to identify there by better estimation of signals. Due to this obviousreason the spectral width measured by this method is generally higher than that ofconventional method. Figure 5a and 5b shows the Doppler width obtained through multitaperand rectangular window for west and Zenith-X beam respectively. Multitaper spectralestimate always shows higher Doppler width in all beams. Since the valley point of signalpeaks is able to identify correctly in multitaper spectral estimate this estimation may be moreaccurate. The Doppler width is one of the important parameter for studying the turbulenceand dynamics of the atmosphere, the improvement in measuring the Doppler Width is distinctadvantage in this method. The analysis is carried out on all beams and similar result isobtained.132