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SAR(Synthetic Aperture Radar)反演海洋风矢量是当今微波遥感领域非常有意义的前沿课题.本文首先介绍了星载SAR估算海面风向、风速的基本原理和三种主流反演算法,接着给出反演的流程图以及重要步骤.然后,以2002年5月7日香港地区ERS-2 SAR海洋图像为例,对经典的SWDA(SAR Wind Direction Algorithm)-谱分析方法加以改进,求得具有180°模糊度的风向,并用香港天文台气象浮标实测数据消除了风向不确定性.最后,利用CMOD4GMF(Geophysical Model Function,地球物理模式函数)计算得到海面上10m高的风速.与气象浮标站实测资料相比,利用ERS-2 SAR图像获取的海面风向、风速的精度均较高.这一结果表明:如果对SAR预先进行ADC(Analog toDigital Converter)改正以及精确校准,结合改进的SWDA和CMOD4,可以获得高精度的风矢量.
SAR (Synthetic Aperture Radar) inversion of marine wind vector is a very significant frontier topic in the field of microwave remote sensing now.In this paper, the basic principle of spaceborne SAR estimation of wind direction and wind speed and three kinds of mainstream inversion algorithms are introduced firstly, Flow chart and key step of the application.Secondly, taking the SARS image of Hong Kong SAR on May 7, 2002 as an example, we improved the classical SAR Wind Direction Algorithm (SWDA) And the wind direction uncertainty of the ambit of the Hong Kong Observatory was eliminated.Finally, the wind speed of 10m above the sea surface was calculated by using the CMOD4GMF (Geophysical Model Function) .Compared with the measured data from the weather buoy station , And the accuracy of wind speed and wind direction obtained by ERS-2 SAR imagery is high, which shows that if ADC (Analog to Digital Converter) correction and accurate calibration are combined with improved SWDA and CMOD4, high Accuracy of the wind vector.