冰的热辐射偏振特性研究

Study on the Thermal Radiation Polarization Characteristics of Ice

冰作为全球能量平衡、气候、水文和生态模型中的重要参数,直接影响到地气系统能量平衡、天气和气候变化等,利用热红外波段对冰偏振特性研究国内外尚未见报道,运用热红外技术对冰热辐射偏振研究有重要意义。研究结果表明,波段、探测角、偏振角对冰热辐射偏振特性均有较大影响,而方位角影响不显著。振辐亮度表现为:LCH1>LCH3>LCH4>LCH2,偏振亮温表现为TCH4>TCH1>TCH2>TCH3,对冰热辐射偏振特性研究选择第三通道偏振亮温数据更优。探测角对冰热辐射特性影响极其显著且受偏振角影响,冰在探测角10°、偏振角30°处偏振亮温最低,这非偶然因素造成,与冰自身特性有关,探测角对冰偏振度影响表现为P0<P40<P10<P20<P50<P30,偏振度大小与各偏振角的亮温差异大小直接相关,方位角对冰偏振亮温影响不显著,表面粗糙程度与组织结构差异直接导致冰在不同方位角发射辐射差异,利用偏振度对冰理化特性监测具有重要作用。

As an important parameter of the global energy balance ,climate ,hydrological and ecological model ,ice directly af-fects the energy balance of the earth-atmosphere system ,weather and climate .It is of great significance to use the thermal infra-red polarization technology to study ice thermal radiation .For the ice monitoring and the impact of global climate change on the ice ,studies on ice thermal radiation polarization characteristics were conducted based on the wavelength ,detection angle and azi-muth angle .The results show that the wavelength has an obvious impact on the ice thermal radiation polarization properties .The polarized radiance of four bands shows that LCH1 〉 LCH3 〉 LCH4 〉 LCH2 while the polarization brightness temperature shows that TCH4 〉 TCH1 〉 TCH2 〉 TCH3 .It’s better to use the brightness temperature of the third channel than the radiance to study the ther-mal radiation polarization .The detection angle affects the ice thermal radiation polarization characteristics greatly and there are some differences between the polarization angles .The brightness temperature of ice is the lowest in the detection angle of 10＆#176; and the polarization angle of 30＆#176; ,which are non-accidental factors .These was closely related to ice physical and chemical properties . The degree of ice polarization performance shows that P0 〈 P40 〈 P30 〈 P50 〈 P10 〈 P20 and is affected by the detection angle , which is directly related to the differences in the brightness temperature at different polarization angles .The degree of polariza-tion changes with the azimuth angles and plays an important role in ice physical and chemical characteristics monitoring .The im-pact of azimuth angle on the ice thermal radiation polarization characteristics was not significant .And it is affected by the rough-ness of the surface ,organizational structure and other factors which are direct results of ice emitted radiation at different azimuth ang les .