Radiation transport simulation by means of a fully equivalent operational model

The radiation transport component of atmospheric modelling codes is typically a major contributor to the overall execution time. This paper introduces a fully equivalent operational model (FEOM) as a high speed replacement for traditional transport modules. The input information to the FEOM is the atmospheric trace gases and temperature profiles as a function of altitude as well as the surface temperature and albedo. The FEOM operates by identifying how these latter variables impact the heating rate as a function of altitude. This relationship is compactly represented by the FEOM in terms of a hierarchy of cooperativity relations amongst the input variables thereby producing an accurate equivalent module. In the present test of the concept, water vapor and temperature are treated as altitude dependent inputs, and the FEOM is shown to be better than 97% accurate over a broad input variable range, while simultaneously being approximately 10(3) times faster than the traditional radiation transport module it replaced.