The development of algorithms for atmospheric methane distribution retrieval from IASI/METOP spectra and their validation with MACC/ECMWF reanalysis data

摘要

The algorithm for atmospheric methane distribution retrieval in atmosphere from IASI spectra has been developed. Well-known Levenberg-Marquardt algorithm is expanded for the case of absence of a priori statistics for methane vertical profiles. A modified technique for iterative calculation of averaging kernels and a posteriori errors for every spectrum is suggested. Levenberg-Marquardt method parameter selection for methane (XCH_4) retrieval from IASI/METOP spectra is presented in this work. NCEP/NCAR reanalysis data provided by ESRL (NOAA, Boulder, USA) were taken as initial guess. Surface temperature, air temperature and humidity vertical profiles are retrieved before methane vertical profile retrieval. The data of Monitoring Atmospheric Composition and Climate reanalysis of the European Centre for Medium-Range Weather Forecasts (MACC/ECMWF) were used for the validation of the method and results of methane retrieval from IASI/METOP.