<title>Regular methods of solution of ill-posed problems for remote sensing of Earth atmosphere using high-resolution spectrometry</title>

Abstract

General regular methods of solution of ill-posed inverse problems and their application to geophysical sounding of Earth interior were developing during long time at Institute of Mathematics and Mechanics of Ural Branch of RAS. In this paper we apply the developed regular methods of solution of the inverse problems for retrieval of vertical temperature profiles from high-resolution thermal emission spectra of atmosphere observed at nadir. Synthetic spectra of sensor like 1MG have been used to test the methods in frame of computational experiments of retrieval of vertical temperature profile. These synthetic spectra were simulated for clear sky weak aerosol atmosphere with line-by-line forward model FIRE-ARMS then convoluted with 1MG instrumental line shape function, arid equivalent nose of 1MG was added. In order to retrieve vertical temperature profile within 0-70 km, we used emission spectra of atmosphere of CO₂ band in the range of 680-830 cm^-1. The computational experiments showed good convergence of all methods started from different initial guess profiles to the target T-profile (known T-profile) with average standard deviation in troposphere within 1K. Deviations of different methods are within 1.5 K. The methods were also applied to temperature retrieval from real data of VIRTEM measurements when emission spectra of the atmosphere were obtained simultaneously with measurements of temperature and humidity profiles over water surface using airplane for elevations up to 8 km. It's shown that the regular methods of solution of inverse problem allow retrieving temperature profile from down-looking high-resolution atmospheric emission spectra with acceptable accuracy even if initial guess atmospheric states are quite far from the target T-profile.