Application of principal component analysis to high spectral resolution radiative transfer: A case study of the O2 A band

Radiative transfer computation is the rate-limiting step in most high spectral resolution remote sensing retrieval applications. While several techniques have been proposed to speed up radiative transfer calculations, they all suffer from accuracy considerations. We propose a new method, based on a principal component analysis of the optical properties of the system, that addresses these concerns. Taking atmospheric transmission in the O_2A band as a test case, we reproduced the reflectance spectrum at the top of the atmosphere (TOA), obtained using the multiple scattering code DISORT, with an accuracy of 0.3%, while achieving an order of magnitude improvement in speed.