General perturbation technique for the calculation of radiative effects in scattering and absorbing media

Recently it has been shown that the perturbation technique, based on joint use of both the direct and the adjoint solutions of the radiative transfer equation, is a powerful tool to solve and analyze various time-independent one-dimensional problems of atmospheric physics such as the calculation of weighting functions, prediction of radiative effects, and development of retrieval algorithms. Our primary goal is to obtain a general formulation of the perturbation technique for the most general case of the radiative transfer problem: time-dependent problems, with regard to polarization, and any possible external sources of radiation such as laser beams and solar illumination. Possible areas of application of the perturbation technique are discussed, and several examples to illustrate them are provided. The accuracy of this technique is discussed by considering the particular examples.