Determination of content of columnar CO2 from solar transmission measurements

The retrieval technique for sensing the columnar content of CO 2 via differential solar transmission measurements in and out absorption bands is presented. The calibration procedure based on the line-by-line method is described. The k-distribution method is used for acceleration calculation. The multiwavelength Sun-photometer has six channels for measurements in and out the H 2 O, CO 2 , CH 4 absorption bands. The interferometer filters are used for spectral selection with resolution (Delta) (lambda) /(lambda) approximately equals 0.01 - 0.02. The wavelengths are centered at 0.87, 0.94, 1.06, 2.06, 2.18, 2.32 micrometers. Errors of the columnar content retrieval connected with the parametrization of atmospheric transmittance and uncertainties of the spectroscopy information are analyzed. The correction of signal on the basis of the measurements of aerosol optical depth is described.