Study of Doppler spectra of radar sea echo
Study of Doppler spectra of radar sea echo
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雷达海面回波多普勒频谱研究
DOI：
10.1029/jc075i003p00551
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发表时间：
1970
影响因子：
--
通讯作者：
M. Laing
中科院分区：
文献类型：
--
作者：
G. Valenzuela;M. Laing
对雷达海回波的多普勒频谱进行了理论和实验研究。利用有限高度重力波的流体力学基本原理，建立了基于复合粗糙表面（即叠加在载流子水波上的布拉格共振水波）的电磁散射模型。然后，这些想法被带到海上，在那里，“完全发展”的假设产生了波高依赖于雷达海回波光谱的宽度，形式为~ H0.4-0.6， H是载体水波的高度。利用多频相干脉冲雷达（428、1228、4455和8910 MHz）在0.3 ~ 0.6 m、0.5 ~ 1 m/sec风和8 m、23 ~ 24 m/sec风条件下对雷达海回波频谱进行了新的实验研究，结果表明，雷达海回波的频带宽度与极化和频率有关，水平极化和垂直极化频谱的差多普勒与频率和降压角有关。光谱的“噪声”和水平返回的更大宽度都表明，海面上的“喷雾”可能是促成这些依赖性的参数之一。根据复合散射面建立的简单模型可以得出雷达海回波光谱宽度的数量级和波高依赖关系，但不能给出其极化依赖关系。
Doppler spectra of radar sea echo is investigated theoretically and experimentally. Electromagnetic scattering models using composite rough surfaces (i.e., Bragg resonant water waves superimposed on a carrier water wave) are developed by means of the basic principles in hydrodynamics applied to a gravity wave of finite height. The ideas are then carried over to the sea, where the assumption of “fully developed” yields a wave height dependence for the width of the spectra of radar sea echo of the form ∼H0.4–0.6, H being the height of the carrier water wave. New experimental results on spectra of radar sea echo with a multifrequency coherent pulsed radar (428, 1228, 4455, and 8910 MHz) for sea conditions, which ranged from 0.3- to 0.6-meter waves with 0.5- to 1-m/sec winds to 8-meter waves with 23- to 24-m/sec winds, show that the band width of radar sea echo is dependent on polarization and frequency, and the differential Doppler between the spectra for horizontal and vertical polarization is dependent on frequency and depression angle. Both the “noisiness” of the spectra and the greater width of the horizontal return indicate “spray” over the sea might be one of the parameters contributing to these dependencies. The simple models developed in terms of composite scattering surfaces are shown to yield the order of magnitude and the wave height dependence for the width of the spectra of radar sea echo, but they fail to give its polarization dependence.