The paper presents a modification of the method of parametric estimation of atmospheric distortion in MODTRAN model as well as experimental research of the method. The experimental research showed that the base method does not take into account physical meaning of atmospheric spherical albedo parameter and presence of outliers in source data that results to overall atmospheric correction accuracy decreasing. Proposed modification improves the accuracy of atmospheric correction in comparison with the base method. The modification consists in the addition of nonnegativity constraint on the atmospheric spherical albedo estimated value and the addition of preprocessing stage aimed to adjust source data.