Retrieval of Temperature Profiles in the MLT Region Using the O2(b1Σ) Airglow With Spectral Contamination Correction of N2 1 PG Emissions

The O (2) -A band airglow near 762 nm is well suited for remote sensing of global temperature in the MLT region. However, vibrational-rotational emission lines of the N (2) 1PG 3-1 transition overlaps with the O (2) -A band, and this spectral contamination (SC) will inevitably affect the accuracy of temperature retrieval. A temperature retrieval method to eliminate N (2) 1PG SC is proposed based on the theory of airglow spectroscopy and the channel transmission function of the Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI). The spectral distributions of the N (2) 1PG band airglow and the O (2) -A band airglow are simulated according to the most recent photochemical model, and based on which the contamination of the N (2) 1PG band spectrum is eliminated by subtracting its intensity in the MIGHTI background channel from the sampling channel. The airglow radiation after the elimination of the SC is processed by using the "onion peeling" algorithm to obtain signal contribution from the target layer for temperature retrieval. The self-consistency of MIGHTI is verified and the MIGHTI official temperature and the measured data from the Atmospheric Chemistry Experiment Fourier Transform Spectrometer (ACE-FTS) are compared to analyze the accuracy and rationality of the algorithm for eliminating SC. Results show that the self-consistency of the two channel combinations is improved by 80 % and the identical degree of MIGHTI and ACE-FTS measurement results is raised by 42 % after SC elimination.