Overview of CERES cloud properties derived from VIRS and MODIS data

The NASA Clouds and Earth's Radiant Energy System (CERES) is providing simultaneous measurements of the radiation and cloud fields on a global basis to improve the understanding and modeling of the interaction between clouds and radiation at the top of the atmosphere, at the surface, and within the atmosphere. Cloud properties derived for CERES using the Moderate Resolution Imaging Spectroradiometer (MODIS) on the Terra and Aqua satellites and the Visible Infrared Scanner (VIRS) on the Tropical Rainfall Measuring Mission satellite are compared to ensure consistency between the products to ensure the reliability of the retrievals from multiple platforms at different times of day. The results are also compared to other cloud databases including those derived by the MODIS science team to determine differences and consistencies among the various analyses. Initial comparisons between 5 years of Terra data and 2 years of Aqua data for cloud fraction, height, optical depth, phase, effective particle size, and ice and liquid water paths from the two satellites show excellent consistency. Differences between the Aqua and Terra results are generally due to diurnally dependent changes in the clouds. Validation of the products has been ongoing using a variety of independent datasets. Those comparisons are summarized to document the uncertainties of the analyses. The results should be extremely valuable for model validation and improvement and for enhancing our understanding of the relationship between clouds and the radiation budget.