An improved cloud mask will be employed for the CERES Edition 3 dataset, expected to begin in 2010. Compared with Edition 2, many improvements have been made in the Edition 3 cloud detection algorithm. These improvements include detecting more daytime ocean cumulus clouds and thin cirrus clouds, better discrimination between polar clouds and snow surfaces as well as between dust and clouds, and a smoother transition from nonpolar to polar regions.
Comparisons between the CERES cloud mask and the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) Vertical Feature Mask (VFM) provides a powerful tool to validate and improve CERES cloud detection globally as well as to understand strengths and limitations of cloud retrievals between active and passive satellite senses. In this paper, examples of improvements in the Edition 3 CERES cloud mask will be presented for different types of clouds over various surfaces. Statistics from comparisons between CERES Edition 3 and CALIPSO VFM will be discussed.