Generated using version 3.0 of the official AMS L A T E X template An improved upper boundary condition for longwave radiative flux in the stratosphere to correct model biases Steven M. Cavallo * , Jimy Dudhia and Chris Snyder National Center for Atmospheric Research † , Boulder, Colorado * Corresponding author address: Steven Cavallo, NCAR Earth System Laboratory, 3450 Mitchell Lane, Boulder, CO 80301. E-mail: cavallo@ucar.edu † NCAR is sponsored by the National Science Foundation 1