A fast method for simulating observations of polarized light emerging from the atmosphere applied to the oxygen A-band

Polarimetry of the atmosphere as a function of wavelength can provide valuable information on atmospheric aerosol and cloud properties. In particular, information can be obtained from polarization observations in wavelength regions where molecular absorption is prominent. Simulation of such observations is, however, extremely time-consuming when using line-by-line radiative transfer calculations. To address this problem, a fast method to simulate such observations was developed, using the adding-doubling method which is especially suited for polarized light, and the correlated k-distribution (ck) method. The part dealing with the ck-method was extended to include instrumental spectral response functions as well as the spectral distribution of the incident solar flux. In our calculations, we used spectral response functions representative for the GOME instrument on board the ERS-2, and focussed on the O