Comparison of temporal cloud variability simulated by a GCM with observations from the Nimbus-7 satellite

Abstract

This paper describes temporal cloudiness variability from Nimbus-7 satellite observations and a GCM simulation. The GCM clouds are parameterized using the cumulative normal distribution function to relate fractional cloud amount with large-scale relative humidity. The global distributions of cloudiness characteristics from both data sources are presented, including their temporal means and standard deviations. For the Nimbus-7 observations, the periods are for DJF and JJA, 1979-1985 while the simulated data are for perpetual January and July. Variances contributed by fluctuations with periods between 2.5 to 6 days, and >10 days are extracted. Both observed and simulated cloud variability fie..