以X-band航海雷達進行波浪觀測時，是利用海面的回波訊號經由波譜計算的方法獲得相關的波浪參數，因此回波訊號的特性將影響到後續的分析結果，本文考慮氣象因素-風及降雨對於雷達回波的影響，改進波高的計算結果。

　　在降雨對於雷達測波的影響上，考慮到降雨會造成雜訊回波及海面回波變強影響，先針對觀測資料進行是否受降雨影響的判斷，利用回波影像的統計特性-平均值與差異係數作為判斷標準，再進一步利用濾波方法濾除降雨雜訊的影響。另外在風的特性對於回波特性的影響上，本文考慮風向、風速對於回波特性的影響，藉由觀測資料的分類，修正風特性對航海雷達測波的影響。

　　在實測資料的分析上，在考慮降雨對雷達測波的影響時，利用影像的統計特性-平均值與差異係數可有效區分降雨及非降雨的觀測資料，其準確率達九成五以上；並進一步以頻域濾波的方式來濾除降雨對回波資料的影響。在考慮風的特性對觀測資料的影響時，將觀測資料依風向、風速進行分類，在波高計算結果上，取其95%信賴區間的範圍分佈在±45公分之間。

　　While observing the wave field with X-band marine radar, the property of microwave backscatter from the ocean surface is affected by meteorological elements. In order to improve the result of wave height estimated, this paper considers the influence of wind and rain to the backscatter.

　　Consider the influence of rainfall on surface backscatter, it will cause the enhancement of rain noise signal and the backscatter from surface. In the beginning, this paper judge whether the data affected by rain. In order to differentiate between the radar images with rain noise and without rain noise, mean value and variation coefficient of radar signals are proposed in this study. It is found that the accuracy of estimation is higher than 95%. It is also proposed frequency domain filtering to filter the rain noise which occurs in radar images.

　　Further, this work considers the influence of wind on backscatter. Because different wind property will cause different backscatter characteristic. The analytical method is classified to different wind directions and wind speeds when it comes to the influence of wind. With the classification to the data by wind, the 95% confidence level of significant wave height is distributed in the range within 45 cm.

[1]劉兆泰、陳人道、江國地、葉世燦，“雷達觀測教材”，幼獅文化事業股份有限公司，1983。
[2]熊雲嵐，“實用船舶雷達”，財團法人徐氏基金會，1991。
[3]光易恆，“海浪 -特性與推算-”，國立成功大學台南水工試驗所，1992。
[4]許明光，“使用衛星雷達研究台灣東北海面粗糙度”，行政院國家科學委員會研究報告，計畫編號：NSC83-0209-M019-010，1994。
[5]高義郎，“利用衛星SAR影像資料推測海洋風浪方向波譜”，國立交通大學碩士論文，1996。
[6]林鴻鵬，“衛星影像分析近岸波場之探討”，國立成功大學碩士論文，1996。
[7]李明靜，“降雨及其與密度層變水面互制之觀測分析”，國立成功大學碩士論文，1997。
[8]謝金原，“太空微波遙感與探測原理及其運用”，科學知識，第46期，17-24頁，1997。
[9]張素梅，“統計學”，三民書局股份有限公司，1997。
[10]呂黎光，“衛星影像應用於波浪能譜分析與近岸水深演算”，國立交通大學博士論文，1998。
[11]李蘊滋、黃培康、郝祖全、林平苹、秦忠宇，“雷達工程學”，海洋出版社，1999。
[12]吳立中，“二維小波轉換應用於波場影像分析之研究”，國立成功大學碩士論文，2002。
[13]Alpers, W., “Monte Carlo simulations for studying the relationship between ocean wave and synthetic aperture image spectra,” Journal of Geophysical Research, Vol. 88, pp. 1745-1759, 1983.
[14]Ang, Weng, and Stephen E. Hobbs, “Weather effects on radar backscatter from crops,” European Space Agency, (Special Publication) ESA SP, Vol. SP-414, No. 1, pp. 311-315, 1997.
[15]Beal, R. C., D. R. Thompson, G. S. Young, H. N. Shirer and T. D. Sikora, “Atmospheric signatures in SAR ocean imagery,” International Geoscience and Remote Sensing Symposium(IGARSS), Vol. 2, pp. 896-898, 1996.
[16]Borge, J. C. N., K. Reichert, and J. Dittmer, “Use of nautical radar as a wave monitoring instrument,” Coastal Engineering, Vol. 37, pp. 331-342, 1999.
[17]Braun, N., M. Gade, and P. A. Lange, “The effect of artificial rain on wave spectra and multi-polarisation X band radar backscatter,” International Journal of Remote Sensing, Vol. 23, No. 20, pp.4305-4323, 2002.
[18]Cox, C. S., and W. H. Munk, “Statistics of the sea surface derived from sun glitter,” J. Mar. Res., Vol. 13, pp. 198-227, 1954.
[19]Crombie, D. D., “Doppler spectrum of sea echo at-13.56 MHz,” Nature, 4459, pp. 681-682, 1955.
[20]De Loor, G. P., “Tower-mounted radar backscatter measurements in the north sea,” Journal of Geophysical Research, Vol. 88, C14, pp. 9785-9791, 1983.
[21]Eliason, E. M. and A. S. McEwen, “Adaptive box filters for removal of random noise from digital images,” Photogrammetric engineering and remote sensing, Vol. 56, No. 4, pp. 453-458, 1990.
[22]Gonzale, R. C. and R. E. Woods, “Digital image processing,” 2nd Ed., Prentice Hall, Inc. Upper Saddle River, New Jersey.
[23]Grønlie, Ø., “Microwave radar directional wave measurement, MIROS Results,” Proc. WMO/IOC workshop on operational ocean monitoring using surface based radars, Geneva, WHO/TD, No.694, pp.73-80, 1995.
[24]Houk, D. and T. Green, “A note on surface wave due to rain,” Journal of Geophysical Research, Vol. 81, No. 24, pp. 4482-4484, 1976.
[25]Krogstad, H. E., and S. F. Barstow, “Recent advances in wave measurement technology,” Proceedings of the Ninth International Offshore and Polar Engineering Conference, pp. 19-26, 1999.
[26]Lemaire, D., L. F. Bliven, C. Craeye, and P. Sobieski, “Drop size effects on rin-generated ring-waves with a view to remote sensing applications,” International Journal of Remote Sensing, Vol. 23, No.12, pp. 2345-2357,2002.
[27]Lee, Jong-Sen, “Refined filtering of image noise using local statistics,” Computer Graphics and image Processing, Vol. 15, pp. 380-389, 1981.
[28]Lee, P. H. Y., J. D. Barter, K. L. Beach, C. L. Hindman, B. M. Lake, H. Rungaldier, J. C. Shelton, A. B. Williams, R. Yee, and H. C. Yuen, “X band microwave backscattering from ocean waves,” Journal of Geophysical Research, Vol. 100, No. C2, pp. 2591-2611, 1995.
[29]Long, M. W., “On a two-scattered theory of sea echo,” IEEE Transactions on Antennas and Propagation, AP-22, pp. 667-672, 1974.
[30]Long, M. W., “Radar reflectivity of land and sea,” 3rd ed., Artech house radar library, ISBN 1-58053-153-9, 2001.
[31]Moore, R. K., Y. S. Yu, A. K. Fung, D. Kaneko, G. J. Dome, and R. E. Werp, “Preliminary study of rain effects on radar scattering from water surfaces,” IEEE Journal of Oceanic Engineering, Vol. OE-4, No. 1, pp. 31-32, 1979.
[32]Moore, R. K., A. Mogili, Y. Fang, B. Beh, and A. Ahamad, “Rain measurement with SIR-C/X-SAR,” Remote Sensing of Environment, Vol. 59, No. 2, pp. 280-293, 1997.
[33]Neito, J. C., K. Reichert, and J. Dittmer, “Use of nautical radar as a wave monitoring instrument,” Coastal Engineering, Vol. 37, pp. 331-342, 1999.
[34]Seemann, J., C. M. Senet, H. Dankert, H. Hatten, and F. Ziemer, “Radar image sequence analysis of inhomogeneous water wave,” Proceeding of SPIE – The International Society for Optical Engineering, Vol. 3808, pp. 536-549, 1999.
[35]Tournadre, J. and J. C. Morland, “The effects of rain on TOPEX/Poseidon altimeter data,” IEEE Transactions on Geoscience and Remote Sensing, Vol. 35, No. 5, pp.1117-1135, 1997.
[36]Wright, “Wave observation by shipboard radar,” Ocean Science and Ocean Engineering, Vol. 1, pp. 506-514, 1965.
[37]Young, I. R., W. Rosenthal, and F. Ziemer, “A three-dimensional analysis of marine radar images for the determination of ocean wave directionality and surface currents,” Journal of Geophysical Research, Vol. 90, No. C1, pp. 1049-1059, 1985.
[38]Young, I. R., “WIND GENERATED OCEAN WAVES”, 1999.
[39]Ziemer, F. and W. Rosenthal, “Measurements of the directional wave spectra by ship radar,” Proc. IAPSO symposium, General Assembly, Int. Assoc. for Phys. Sci. of the oceans, Hamburg, 1983.