Climate change and cloud feedback: The possible radiative effects of latitudinal redistribution

The sensitivity of outgoing longwave flux to changes in cloud cover (partialF/partialA/sub c/) as defined by Cess (1976) must be evaluated carefully to avoid discrepancies arising from the interchange of averaging conventions. In a recent zonal atmospheric model experiment the global value of partialF/partialA/sub c/ was different in sign than in other calculations. This difference in behavior was traced to a latitudinal redistribution of cloud amount and height that occured in the doubled CO2 experiment. However, when partialF/partialA/sub c/ was evaluated at individual latitudes and then weighted globally, the value of this parameter was consistent with those found by Cess (1976) and Budyko