本次觀測事件是利奇馬颱風侵台期間，位於中壢的特高頻雷達對此颱風做連續時間的觀測，其觀測時間從2001年9月24日14:00 LT至28日00:00 LT。在本研究中，我們將求出資料的回波功率、都卜勒頻移量、都卜勒頻寬、訊號雜訊與頻譜，並利用高斯分布函數逼近中性大氣頻譜，以求出中性大氣的徑向速度。本論文中，嘗試利用HHT時頻分析法以及群速與相速分析法研究分析此颱風期間中性大氣垂直徑向速度的波動現象。

During the passage of Typhoon Lekima, a continuous observation was made with a VHF radar located in Chung-Li, Taiwan. The observation period was from September 24 14:00 LT to 29 00:00 LT, 2001. In the thesis, we used the observed data to calculate the echo power, the Doppler frequency shift, spectral width and signal-to-noise ratio by the moment method. We also calculated the spectra of the data and obtained the radial velocity by fitting the Gaussian function to the turbulence spectral component. To analysis the waves of radial velocity during the typhoon period, we use the Hilbert Huang Transform and the vertical phase and group velocities method.

Atlas, D., R. C. Srivastava, and R. S. Sekhon, 1973： Doppler radar characteristic of precipitation at vertical incidence, Rev. Geophys., 11, 1-35.
Baselay, B. B., and K. S. Gage, 1980： The MST radar technique：Potential for middle atmosphere studies, Pure Appl. Geophys., 118, 452-493.
Bedrosian, E., 1963： A product theorem for Hilbert transform, Proc. IEEE, 51, 868-869.
Bendat, J. S., and Piersol A. G., 1986： Random data：analysis and measurement procedures, 2nd edn., Wiley, New York.
Boashash, B., 1992： Estimating and interpreting the instantaneous frequency of a signal, I. Fundamentals, Proc. IEEE, 80, 520-538.
Chu, Y. H., and L. P. Chian, 1991： The investigation of the atmospheric precipitations by using Chung-Li VHF radar, Radio Sci., 26, 717-729.
Gabor, D., 1946： Theorem of communication, Proc. IEEE, 93, 429-457.
Gage, K. S., and B. B. Balsley, 1980： On the scattering and reflection mechanism contributing to clear air radar echoes from the troposphere, stratosphere and mesosphere, Radio Sci., 15, 243-257.
Gunn, R., and G. d. Kinzer, 1949： The terminal velocity of fall for water droplets stagnant air, J. Appl. Meteorol., 6, 243-248.
Huang, N. E., Z. Shen, S. R. Long, M. C. Wu, H. H. Shih, Q. Zheng, N. Yen, C. C. Tung, and H. H. Liu, 1998： The empirical mode Decomposition and Hilbert spectrum for nonlinear and non-stationary time series analysis, Proc. R. Soc. Lond., A 454, 903-995.
Kuo, F. S., Lee K. E., Lue H. Y., and Liu C. H., 1993： Measurement of vertical phase and group velocities of atmospheric gravity wave by VHF radar, J. atmos. Terr. Phys, 55, 1193-1201.
Larsen, M. F., and J. Rottger, 1987： Observation of thunderstorm reflectivities and Doppler velocities measured at VHF and UHF, J. Atmos. Oceanic Technol., 4, 151-159.
Ottersten, H., 1969： Radar backscattering from the turbulent clear atmosphere, Radio Sci., 4, 1251-1255.
Sato, T. H., H. Doji, H. Iwai, I. Kimura, S. Fukao, M. Yamamoto, T. Tsuda, and S. Kato, 1990： Computer processing for deriving drop-size distributions and vertical air velocities from VHF Doppler radar spectra, Radio Sci., 25, 961-973.
Tatarskii, V. I., 1961： Wave propagation in a turbulenct media, McGraw-Hill, New York, 258pp.
Ulbrich, C. W., 1983： Natural variations in the analytical from of the raindrop size distribution, J. Appl. Meteorol., 22, 1764-1775.
Wait, J. R., 1962： Electromagnetic wave in stratified media, Pergamon Press, New York, 305pp, 1962.
Yah, K. C. and C. H. Liu, 1974： Theory of ionosphere waves, Academic Press, New York, 464pp.
陳崗熒, 2001： 以HHT時頻分析法剖析赤道區電離層F層電漿空腔結構, 博士論文, 國立中央大學太空科學研究所.
蕭俊傑, 1997： 利用電離層雷達研究電離層波動之垂直群速與相速, 碩士論文, 私立輔仁大學物理學研究所.