We consider relationships of solar radiation transfer in the water vapor absorption band at 940 nm in cloud-free atmosphere and in the presence of broken clouds (for summer conditions of Novosibirsk). It is shown that the calculations with underestimated (overestimated) values of the H2O content in the atmosphere lead to errors in calculated fluxes of downward radiation. At the center of the absorption band, these errors can reach tens of percent. The neglect of continuum absorption in the 870-1030 nm region leads to overestimation of the atmospheric column absorption by 0.8-1.5 W/m2 (at the solar zenith angle of 30°), depending on the water vapor content. The spectral fluxes we have calculated ourselves well compare with the data of field measurements obtained at the ARM SGP site during the campaign in 1997-1998.