通常用大气能见度表征大气对可见光波段的视觉影响程度，但它并不适用于红外波段。鉴于大气能见度的直观特性和红外光电技术的迫切需求，参照可见光大气能见度的定义，依据红外系统对比度阈值，提出了红外大气能见度的概念。根据这里提出的定义和涉及的红外大气透射率的物理过程，分析了决定红外大气能见度的关键大气因素。一般情况下，这些因素是可见光大气能见度、水汽含量、气溶胶类型。建立了红外大气能见度与这些关键参数间的定量关系，计算了噪声等效温差(NETD)为0.05 K 对应的3个大气窗口(1.06、3~5、8~12 μm)的红外大气能见度。

Usually, atmospheric visibility is used to describing the atmosphere′s visual effects in the visible light, but it does not apply to infrared wavelengths. In view of the visualized characteristics of atmospheric visibility and the pressing needs of the infrared electric technology, based on the infrared system contrast threshold, referring to the definition of visible light atmospheric visibility, the concept of infrared atmospheric visibility is put forward. According to the definition presented here and the physical process of infrared atmospheric transmittance involved in, the key determinants factors of infrared atmospheric visibility are analyzed. Generally, these factors are atmospheric visibility of visible light, absolute humidity and aerosol types. the quantitative relationship between the infrared atmospheric visibility and these factors is estabished, and the infrared atmospheric visibility of atmospheric windows (1.06,3~5,8~12μm)is calculated, whose noise equivalent temperature difference (NETD) is 0.05 K.