A new Einstein coefficient method for mesopause-lower thermosphere atmosphere temperature retrieval under a non-local thermal equilibrium situation.

The mesopause-lower thermosphere (MLT) region is an important spatial region in the Earth's atmosphere, making it a valuable area to investigate the temperature variations. Kirchhoff's law fails with the altitude increase due to the non-local thermal equilibrium effect, resulting in an increase in the error of the method to retrieve the atmospheric temperature in the MLT region using the A-band spectral line intensity. In the non-LTE state, the temperature retrieval method based on the Einstein coefficients is proposed to retrieve atmospheric temperature in the 92-140 km height range using the airglow radiation intensity images obtained from the Michelson Interferometer for global high-resolution thermospheric imaging (MIGHTI) measurements.