Weare, B. C. and I. Mokhov, 1995a: Evaluation of total cloudiness
and its variability in the Atmospheric Model Intercomparison Project. Journal
of Climate, 8, 2224-2238.
Total cloudiness of 29 models participating in the Atmospheric
Model Intercompanson Project is compared with the ISCCP C2 as well as the
Nimbus- 7 and Meteor observational estimates. The root-mean-square differences
between the annual means of the model calculations and the C2 observations
after global means are removed vary from about twice to nearly four times
the difference between the C2 and Meteor observations. The large differences
are in some cases due to the fact that although a model qualitatively has
patterns of spatial variations similar to those of the observations. the
magnitude of those variations is much too small. In other cases the models
have produced the approximate magnitude of the spatial variability of the
observations but display sizable errors in the pattern of that variability.
Deficiencies with respect to the model simulations of the mean seasonal
cycle are also pronounced. For instance, the differences between the zonal
averages of total cloudiness for contrasting seasons suggest that near
60° most models predict minima in cloudiness in summer. whereas observations
strongly suggest the opposite. In addition, smoothed seasonal cycle analyses
suggest that a portion of these defiaendes in some models is the result
of a simulated seasonal cycle that leads that of the observations by about
two months. However, some models, which appear to have the proper phase
of the seasonal cycle, still show large root-mean-squared differences and
small correlations when compared with the smoothed seasonal