A reformulated three-layer sea ice model

A model is presented that provides an efficient approximation to sea ice th ermodynamics for climate studies. Semtner's three-layer framework is used, bur the brine content of the upper ice is represented with a variable heat capacity as is done in more physically based models. A noniterative fully i mplicit time-stepping scheme is used for calculation of ice temperature. Th e results of the new model are compared to those of Semtner's original mode l.