A highly miniaturized satellite payload based on a spatial heterodyne spectrometer for atmospheric temperature measurements in the mesosphere and lower thermosphere

Abstract

Abstract. A highly miniaturized limb sounder for the observation of the O 2 A-Band to derive temperatures in the mesosphere and lower thermosphere is presented. The instrument consists of a monolithic spatial heterodyne spectrometer (SHS), which is able to resolve the rotational structure of the R-branch of that band. The relative intensities of the emission lines follow a Boltzmann distribution and the ratio of the lines can be used to derive the kinetic temperature. The SHS operates at a Littrow wavelength of 761.8 nm and heterodynes a wavelength regime between 761.9 nm and 765.3 nm with a resolving power of

Reevaluating the Use of O2 a1Δg Band in Spaceborne Remote Sensing of Greenhouse Gases

“…The volume emission rate (VER, in photons/cm 3 /s) is the integration of r g over the entire band, and the O 2 (a 1 Δ g ) number density is just the VER divided by the electronic-vibrational Einstein A coefficient (2.27× 10 −4 s −1 , calculated from HITRAN2016 individual line intensities using equations 18 and 32 from Gamache & Goldman, 2001). The O 2 a 1 Δ g state has a long lifetime (73 min), which assures that the molecule is in rotational equilibrium with the ambient atmosphere (Kaufmann et al, 2018). A simplified assumption is that r g scales with the absorption cross section:…”