不同介电常数模型的平静海表面亮温仿真差异性分析

Simulation Analysis of Brightness Temperature Difference of Flat Sea Surface with Various Dielectric Constant Models

利用介电常数模型仿真平静海表面亮温是海洋盐度遥感反演的基础工作之一。利用Matlab软件对K-S模型、M-W模型和Bl模型3种介电常数模型进行了仿真。首先分析了3种介电常数的实部和虚部值随电磁波入射角变化的差异性,然后通过介电常数模型获得的3种平静海表面亮温,分析了在盐度为30~40 psu以及不同入射角的情况下,3种介电常数模型得到的平静海表面亮温和盐度变化率的关系。研究结果表明,在L频段(1.4~1.427 GHz),3种模型的差异主要体现在实部,K-S模型介电常数实部值相对于其他2个模型更高,电磁波衰减程度基本一致;在入射角为55°时,亮温与盐度的变化率差异最明显,3种模型的垂直极化亮温的变化率比水平极化亮温高30%左右。

Using the dielectric constant model to simulate the brightness temperature of flat sea surface is one of the basic work of marine salinity remote sensing inversion.By using the Matlab software to K-S,M-W model and Bl model,three kinds of dielectric constant has been carried on the simulation.Firstly analyze the three kinds of real part and imaginary part of dielectric constant value changing with the electromagnetic wave incident angle difference,and then through the dielectric constant model of three kinds of brightness temperature,flat sea surface salinity is analyzed in 30~40 psu and the cases of different incident angle,three kinds of calm sea surface model for dielectric constant brightness moderate salinity gradient relationship.The results show that in the L-band(1.4~1.427 GHz),the differences of the three models are mainly reflected in the real part.The real part value of the dielectric constant of the K-S model is higher than that of the other two models,and the degree of electromagnetic wave attenuation is basically the same.When the incident angle is 55°,the most obvious difference on the rate of change of temperature and salinity,three models of the rate of change of vertical polarization brightness temperature higher than the horizontal polarization brightness temperature is about 30%.