| Summary: | 碩士 === 國立成功大學 === 水利及海洋工程學系碩博士班 === 93 === 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.
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