不同海域多波段小擦地角海面散射特性的影响因素分析

Elements affecting low-grazing-angle electromagnetic scattering properties from ocean surface at multi-band in different sea area

根据东南沿海和西太平洋海面温度场与盐度场卫星数据,利用双Debye模型以及含泡沫的M-G模型计算等效介电常数.分析表明:不同海域温度与盐度变化对P/L波段介电常数虚部的影响大于实部,其他频段影响略小;但介电常数对给定频率的海面散射系数影响只在0.1dB左右,故主要影响仍来自于不同海域的海情海况.基于修正双尺度法和矢量辐射传输理论,提出了多尺度海面电磁散射的含泡沫修正双尺度方法,考虑实际海面海况与不同频率的截断波数,数值计算了不同波段(即P、L、S、X、Ku波段)频率海面后向散射系数随风速风向、波高、泡沫覆盖率、频率与极化等影响因素的变化情况,总结分析了基于多尺度海面小擦地角电磁散射机理.

Based on satellite data of sea surface temperature and salinity at Southeast coast and the Western Pacific, dual-Debye model and M-G mixed media theory with foam are applied to calculating sea effective permittivity, analysis shows that different area changes in temperature and salinity will have great impact on imaginary part of permittivity at P/L-band and have little impact on other bands, where the affecting of permittivity on a given frequency sea scattering coefficient has the range of only 0.1 dB, thus the sea condition and state are of significant importance. Based on the modified two-scale model and VRT, considering the cut-off wavenumber at different frequency and sea states, numerical results show the low grazing angle electromagnetic backscattering at multi-band (P/L/S/X/Ku-band) in different sea area, and the affection of wind speeds and directions, foam cover, frequencies and polarization are considered at the same time. The mechanism of multi-scale low grazing angle electromagnetic scattering is also analyzed. Copyright © 2015 by Editorial Department of Chinese Journal of Radio Science