On the relationship between the Chahine-Twomey and maximum entropy methods

The problem of estimating atmospheric temperature and composition profiles from satellite-sensor or ground-sensor radiance measurements is generally ill-conditioned, so that constraints must be imposed to obtain a unique solution. A number of estimation methods have been developed, some of which incorporate explicit constraints whilst in others the constraints are implicit. In this correspondence we relate the Chahine-Twomey method to a special case of the Maximum Entropy method. This relationship provides insight into the operation of the Chahine-Twomey method, and explains how this method incorporates a priori information. -Authors