All-Sky scene, also known as total, is determined from all CERES footprints (20 km nominal resolution) within the given temporal or spatial domain.
Clear-Sky scene has different algorithms depending on the product ERBE-like, Single Scanner Footprint TOA/Surface Fluxes and Clouds (SSF), or Energy Balanced and Filled (EBAF). ERBE-like clear-sky scene is determined from CERES footprints that were crudely identified as clear using the ERBE scene id algorithm which uses climatological, zonal LW thresholds and appropriate SW thresholds based on 12 scene ids.
EBAF & SSF clear-sky scenes are determined from CERES footprints that are 99% clear as identified by CERES-MODIS clear-sky mask from the MODIS pixels contained within the CERES footprint. SSF clear-sky products contain many cloudy regions that may have no clear-sky observations for one particular month with no attempts to fill these regions. The EBAF clear-sky products filled all non-observed clear-sky regional fluxes for a complete clear-sky global map, and all temporal and spatial domains should have clear-sky fluxes.