ANALYSIS OF GLOBAL CLOUDINESS .2. COMPARISON OF GROUND-BASED AND SATELLITE-BASED CLOUD CLIMATOLOGIES

Cloud climatologies are developed and intercompared for International Satellite Cloud Climatology Project (ISCCP) (1983-1988), Meteor 1 (1971-1980), Meteor II (1979-1988), and Nimbus 7 (1979-1985) satellite observations, and for Berlyand and Strokina (1975, 1980) and Warren et al. (1986, 1988) ground-based observations. The satellite annual-mean, global-mean cloudiness, 0.57+/-0.05, is less than the ground-based value, 0.61+/-0.01, predominantly because of the low value for Nimbus 7. There is agreement between the satellite means of ISCCP, 0.62, and Meteor II, 0.61, and the ground-based means of Warren et al., 0.62, and Berlyand and Strokina, 0.60. Each satellite- and ground-based climatology shows that the hemispheric- mean cloudiness is larger in summer than that in winter in both the northern and the southern hemispheres. Excluding Nimbus 7 observations, the zonal- mean cloudiness distributions for January, July, and July minus January display reasonably good agreement between 60-degrees-S and 60-degrees-N. In polar latitudes there is significant disagreement among the different climatologies, even in the sign of cloudiness changes from winter to summer. This evinces the need for special cloudiness experiments in polar regions, particularly in winter and summer.