海洋水色卫星紫外波段的偏振特性分析

Polarization Characteristics of Ultraviolet Bands Observed by Ocean Color Satellites

针对水色卫星遥感器的紫外波段,利用海洋-大气耦合矢量辐射传输模型开展了355nm和385nm两个紫外波段大气顶(TOA)表观辐射的偏振特性分析。研究发现水色卫星紫外遥感器入瞳处光的偏振信号主要来源于大气分子散射,与仅考虑大气分子散射相比,气溶胶、水-气界面层和水体会减弱紫外遥感器入瞳处光的总偏振度(DOP)。在不同的大气顶观测方位下,上述两个波段紫外光的总偏振度变化范围在0%~70%之间。同水色卫星遥感器通常设置的412nm可见光波段相比,在同一条件下到达水色卫星紫外遥感器入瞳处的紫外光的偏振度变化不大。

Using the ultraviolet band observations from the ocean color satellites,this study has employed a coupled ocean-atmosphere vector radiative transfer model to analyze the ultraviolet polarization characteristics of 355-nm and 385-nm radiation measured at the top of atmosphere(TOA).Results showed that atmospheric molecules contributed most toward the polarization of the ultraviolet radiation reaching the ocean color satellite sensors.Compared with the condition that solely accounts for atmospheric molecules,aerosols,air-sea surface,and water body could also weaken the total degree of polarization(DOP)of ultraviolet radiation reaching the ultraviolet satellite sensors.The total DOP of 355-nm and 385-nm radiation varied in the range of 0%--70%with different TOA viewing zeniths.Compared with the visible band of 412nm that is usually set by ocean color satellite sensors,the TOA DOP of ultraviolet radiation reaching the satellite sensors exhibited insignificant differences under the same condition.