Determination of characteristics of the gaseous composition of the atmosphere from measurements of the downward IR thermal radiation

A method of remote sensing atmospheric minor gases (MGs) is considered. The method is based on measurements of the downward thermal radiation in the s pectral range 3-17 mum with Fourier spectrometers of high resolution (0.3-1 .0 cm(-1)). A procedure for interpretating the Fourier spectra is proposed, a numerical simulation of the experiments is performed, and results of fie ld observations are obtained. A correlation between the measured radiation spectra and the computed ones is carried out. It is shown that an additiona l calibration of the measured spectra leads to a good agreement between the se spectra. A procedure to interprete the observational data is proposed an d studied in numerical experiments. This procedure makes it possible to det ermine the atmospheric parameters and to refine the parameters of the radia tive model and of the absolute calibration of the spectra. The numerical ex periments show that the retrieval errors are in the range of their estimate s obtained earlier. It is found that the results of the field measurements are in good agreement with independent results. The studies show that the m ethod of remote sensing provides a possibility for determining the troposph eric ozone content (with an error of 4-6%) and of the total contents of a s eries of MGs, such as H2O (with an error of 2-3%), CH4, N2O, CFC-11, and CF C-12 (with an error of 5-8%).