A Simplified Algorithm to the Atmospheric Transmittance

Abstract

It is very complex that the infrared radiation's actual transmission process through earth's atmosphere. There is interaction between radiation and atmospheric component. The radiation transmittance will be weakened because of the absorption and the scattering. The atmospheric transmittance is an important parameter to measure the attenuation. This paper summarizes the infrared radiation's transmission process in atmosphere, studies the computation method of atmospheric transmittance, analyzes the absorption attenuation of the atmospheric gas such as steam and carbon dioxide, the scattering attenuation and the attenuation caused by meteorological condition, infers the computation method of the atmospheric equivalent path, and gives the atmospheric transmittance simplified algorithm. Finally this paper gives the atmospheric transmittance computation result under given meteorological condition, also gives the contrast curve with LOWTRAN7.0. The algorithm has certain reference value in the project application. The problem that the infrared radiation transmits in the atmosphere is always paid attention by the designers who deal with the photoelectricity measurement system and the researchers who deal with the radiation transmission in the earth atmosphere. There is more and more attached importance to the research of the atmospheric transmission model. There are many studies relating to the atmospheric transmission characteristic of infrared radiation, such as the object infrared detection, the navigation, the communication, the earth resource distance survey, etc. Generally there are three atmospheric radiation transmission models such as LOWTRAN, MODTRAN and FASCODE. These application softwares are developed by Air Force Geophysics Laboratory of America (AFGL) according to different application purpose. But it is complex to use these softwares by many project personnel. This paper gives a kind of atmospheric transmittance simplified algorithm.