The approximate calculation of atmospheric path radiance in close range and horizontal direction

Atmospheric path radiance is the key factor in the accuracy of objective radiation measurement. In the traditional radiation character measurements, under the help of the atmospheric observation equipment, MODTRAN and other software likewise, the indeterminacy rate could be around 10 similar to 20%, it is highly restricts the measurement accuracy of objective radiation. For this reason, it is quite significant to develop the study of measure and calculation in path radiance. The approximate calculation formula for path radiance in close range and horizontal direction is expressed in this article; it is compared with the results of MODTRAN and measurement in experiment. It is revealed that the accuracy of software is 7.8%, and the formula is 4.9%, which could demonstrate the validity of the approximate calculation formula in close range and horizontal direction. In this article, in the process of deducing and experiment, the validity of the approximate calculation formula in close range and horizontal direction is fully proved, which supply a new method in approximate calculation of path radiance for objective radiation measurement.