K-binning: A new approach to simulate narrow band satellite channels in layered atmospheres with varible gas absorption

We present a new approach to optimally simulate the transmission characteristics of gaseous absorption bands. This approach is similar to a k-distribution approach but overcomes the main shortcommings of a conventional k-distribution. The major differences are 1) that for a given spectral intervall no assumptions about the shape of the sensor weighting function have to be incorparated a-priori, 2) that not only the total atmospheric transmission is accuratly described, also the transmission estimation of each atmospheric layer is precise (which is pariculary important for radiative transfere simulations in cloudy atmospheres) and 3) that spectral regions with mixing contributions of different absorbing gases can precisely be described by one set of k-terms, since the uncorrelated contributions of the different gases to the extincion are decoupled. We will outline the method and apply it to high resolution spectroscopic simulations in the oxygen-A-band (corresponding to the orbiting Carbon Observatory O-C-O)