The representation of water vapor and its dependence on vertical resolution in the Hadley Centre Climate Model

Simulations of the Hadley Centre Atmospheric Climate Model version 3, HadAM 3, are used to investigate the impact of increasing vertical resolution on simulated climates. In particular, improvements in the representation of wa ter Vapor and temperature in the upper troposphere and lower stratosphere a re identified with more accurate advection. Degradations in some aspects of the simulation in the Tropics are identified with undesirable resolution d ependencies in the physical parameterizations. The overall improvements in the water vapor and temperature distribution lead to improvements in the cl ear-sky longwave radiative fluxes with higher vertical resolution.