The preparation of optical constants for line-by-line and Lebesgue calculations of atmospheric radiation transport

The paper contains a description of the programs to calculate the absorption coefficients, which are the input data for the radiation transport calculation in Earth's atmosphere by the "line-by-line" method and by the Lebesgue averaging method. We describe two preparation procedures of the Lebesgue coefficients: "accurate" and "express", that uses the Lebesgue crossection database.