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姓名 鄭倩敏(Chin-Min Tee) 查詢紙本館藏 畢業系所 太空科學研究所 論文名稱 電離層散塊E層3公尺不規則體凍結效應之研究
(A study of Frozen-in property of 3-m plasma Irregularities in Ionospheric Sporadic E layer)相關論文 檔案 [Endnote RIS 格式]
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摘要(中) 本文利用中壢特高頻雷達觀測電離層散塊E層不規則體的頻譜特徵估計其在東西方向上的速度分量。由雷達干涉法定位配合moment method 所求得的回波功率、平均都卜勒速度與頻譜寬，可以更進一步分析不規則體在三度空間回波區當中飄移的特性。分析資料過程中發現在不規則體回波的都卜勒速度,會隨著不規則體的東西方向上偏離波束主軸的夾角增加而成一正相關的關係,因此我們可以假設都卜勒頻寬加寬的現象有可能是因為不規則體在橫過波束主軸方向上的飄移所產生的波束加寬效所造成.在這篇論文當中討論到計算最適合計算水平飄移速度四種最小平方趨近法, 其中由實際高度所獲得的水平飄移速度是最合適的.我們使用這種方法來求出來理論徑向速度並將此速度與實際觀測到的都卜勒速度比較發現,兩者的相關性非常好(大於 0.8), 而且相減後根均方值都介於1-3(m/s)之間. 這表示了在1997/8/8這天的某段資料當中, 波束加寬效應對回波速度的貢獻扮演著相當重要的角色。 摘要(英) The effects of along and transverse radar beam drifts of sporadic E field-aligned irregularities localized in the expected echoing region on mean Doppler velocity and spectral width are theoretically investigated in this thesis. Detailed analysis shows that the Doppler velocities are nearly linearly proportional to the mean angular distance of the irregularities from the radar beam axis decreases with the increase of the horizontal dimension of the plasma structure. Therefore it suggests that the beam broadening effect caused by the drift of the field-aligned irregularities across the radar beam in the geomagnetically zonal direction may play a role in broadening the Doppler spectral width. Four different algorithms for best fitting plasma irregularity data to theoretical expression are discussed here to obtain the optimal solution of transverse beam drift velocity. In order to facilitate mathematical manipulation, the comparison between estimated radial velocity and observed Doppler velocity is made and correlation analysis is also discussed in the articles. In a special case, however, the correlated coefficient between observed Doppler velocity and estimated radial velocity can be as large as 0.8 or more; and the Root-mean-square (RMS) error is in the range of 1 – 3 (m/s). We find that the algorithm of the least squares fit in terms of radar spectra at fixed height for long duration will result in the best solution for the estimation of transverse beam drift velocity. It is easy to see that the beam broadening effect caused by the drift of the field-aligned irregularities across the radar beam in the geomagnetically zonal direction do play a role in broadening the Doppler spectral width. 關鍵字(中) ★ 電離層 關鍵字(英) ★ sporadic E irregularities 論文目次 Chinese abstract i
English abstract ii
Acknowledgement iii
Table of Contents iv
List of Figures vi
List of Tables xii
CHAPTER 1 Introduction .......................................................1
1.1 The introduction of Chung-Li VHF Radar .........................1
1.2 The characteristic of Es backscatter............................4
CHAPTER 2 Analyzing and modeling echoing region of Chung-Li
VHF radar with IGRF-2000............................................9
2.1 International Geomagnetic Reference Field (IGRF) model..........9
2.2 Es echoing region of Chung-Li radar............................11
CHAPTER 3 Theory introduction......................................14
3.1 Mechanism of E region irregularities...........................14
3.2 Interferometry technique: A method of determining angular position of E region irregularities in the echoing region........................15
3.2.1 Radar Interferometry technique...............................15
3.2.2 Interferometry equation for Ionospheric experiments..........18
3.2.3 Calculate the position of backscatter....................... 22
3.3 Derivation of Beam Broadening Effect for field-aligned irregularities...22
CHAPTER 4 The Experiment Setup and Data Analysis...................31
4.1 Radar parameters..............................................31
4.2 Data analysis.................................................33
4.2.1 Power Spectrum............................................34
4.2.2 RTI plot (Range-Time-Intensity plot)......................35
4.2.3 Cross spectrum, Coherence, phase difference...............36
4.2.4 Three dimensional spatial structures of irregularities obtained from Interferometry technique ..........................................37
4.2.5 Moment method results.....................................39
4.2.6 Application of Moment method to spatial structures of
irregularities............................................41
CHAPTER 5 Studies on the velocity of E region Field Aligned Irregularities..43
5.1 Estimation of Trace velocity....................................43
5.2 Estimation of along radar beam drift velocity...................45
5.3 Beam Broadening Effect..........................................46
5.3.1 The relation of observed Doppler velocity and the azimuth angle of the field-aligned irregularities in the echoing region relative to the beam axis..46
5.3.2 Estimation of transverse beam drift velocity..................48
5.3.3 Comparison of estimated and observed mean Doppler velocities..49
5.3.3.1 Results from mean Doppler velocity.......................49
5.3.3.2 Results from spectral width..............................50
5.4 Four algorithms of the best fit ...............................51
5.5 Analysis of wave modulation ...................................55
5.6 Comparison of Es layers observed by Ionosonde and VHF Radar ...57
5.6.1 comparison of height, thickness, spectral widths and power..58
CHAPTER 6 Conclusion and Discussion.................................60
6.1 Discussion............................60
6.2 Conclusion............................65
References
Figures參考文獻 Chen Y. H., Y. H. Chu, and C. H. Liu, The Observations of Sporadic E Irregurarities in Equatorial Anomaly Crest Zone by Using Chung-Li VHF Radar, J. Geomag. Geoelectr., 48, 1489-1497,1996.
Chu, Y. H., Beam broadening effect on oblique MST radar Doppler spectrum,J. Atmos. Oceanic Technol., 19, 1955– 1967, 2002.
Chu Y. H., and C. Y. Wang, Interferometry investigations of VHF backscatter from plasma irregularity patches in the nighttime E region using the Chung-Li radar, J. Geophys. Res., 104,2621-2631, 1999.
Chu Y. H., and C. Y. Wang, Three-dimensional spatial structures of midlatitude type 1 Es irregularities, J. Geophys. Res., 107, No. A8, 1029, 1999.
Chu Y. H., and C. Y. Wang, Plasma structures of 3-meter type 1 and type 2 irregularities in nighttime midlatitude sporadic E region, J. Geophys. Res., 107, NO. A12, 1447, 2002.
Chu Y. H., and C. Y. Wang, Radial velocity and doppler spectral width of echoes From field-aligned irregularities localized in the sporadic E region, J. Geophys. Res., vol.108(A7), 1282, 2003.
Chu Y. H., and C. Y. Wang, An evidence of beam broadening effect dominating Doppler spectra of field-aligned irregularities in sporadic E region made with the Chung-Li radar. J. Geophys. Res., Vol 110, 2005
Farley, D. T., A theory of Electrostatic Fields in a Horizontal Stratified ionosphere subject to a vertical magnetic field, J. Geophys. Res., 64, No. 9, 1959.
Farley, D T., H. M. Ierkie, and B. G. Fejer, Radar Interferometry : a new technique for studying plasma turbulence in the ionosphere. , J. Geophys. Res., 86, 1467-1472,1981.
Fejer, B. G., D. T. Farley, B. B. Balsley, and R. F. Woodman, Vertical structure of the VHF backscattering region in the equatorial electrojet and
the gradient drift instability, J. Geophys. Res., 80, 1313-1324, 1975.
Haldoupis, C., K. Schlegel and D. T. Farley, An explanation for type 1 radar echoes from the midlatitude E-region ionosphere, Geophys. Res. Lett., 23, 97-100, 1996
Kelly M. C. and Heelis R. A., The Earth’s Ionosphere: Plasma Physics and Electrodynamics, Academic Press, INC., 1989
Riggin D., W. E. Swartz, J. Providakes, and D. T. Farly Radar studies of
long-wavelength waves associated with mid-latitude sporadic E layers, J.
Geophys. Res., 91, 8011-8024, 1986.
Rottger, J., C. H. Liu, J. K. Chao, A. J. Chen, Y. H. Chu, I. J. Fu, C. M. Huang,, Y. W. Kiang, F. S. Kuo, C. H. Lin, and C. J. Pan
The Chung-Li VHF radar: Technical layout and a summary of initial results, Radio Sci., 25, 48-502, 1990
Schlegel, K., Coherent backscatter from ionosphere E-region plasma irregularities, J. Atmo. And Terr. Phys., 58, 933-941, 1996
Schunk R. W., and Nagy, A. F., Ionospheres – Physics, Plasma Physics, and Chemistry, Cambridge University Press, 2000
Sudan, R. N., J. Akinrimisi and D. T. Farly, Generation of small-scale
irregularities in the equatorial electrojet, J. Geophys. Res., 78, 240-248,
1973.
Sudan, R. N., Unified theory of type I and type II irregularities in the Equatorial Electrojet, J. Geophys. Res., 88, 4853 – 4860, 1983
Tsunoda, R. T., Fukao, S. and Yamamoto, M., On the origin of quasi-periodic radar backscatter from midlatitude sporadic E, Radio Sci., Vol 29, 349-365, 1994
Wang C. Y., and Y. H. Chu, Interferometry investigation of blob-like sporadic E plasma irregularity using the Chung-Li VHF radar, Journal of atmospheric and solar-terrestrial physics, vol.63, 123-133, 2001.
Yamamoto, M., N., Komoda, S. Fukao, R. T. Tsunoda, T. Ogawa, and T. Tsuda, Spatial structure of the E-region field-aligned irregularities revealed by the MU radar, Radio Science, 29, 337-347, 1994
http://www.amfmdx.net/propagation/Es.html
http://www.vhfdx.de/
http://fdf.gsfc.nasa.gov/prod_center/database_products_set/IGRF.html
朱延祥，剖風儀觀測原理與應用，國立中央大學太空科學研究所，1994。
龔瑞鳴，利用中壢VHF 雷達進行流星尾觀測系統及方法之建立，博士論文，國立中央大學大氣物理研究所，1998。
王建亞，利用中壢VHF 雷達進行電離層散塊E 層不規則體之觀測，博士論文，國立中央大學太空科學研究所，1999。指導教授 朱延祥(Yen-Hsyang Chu) 審核日期 2006-6-29 推文 plurk
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