The Earth's climate is determined by energy transfer from the sun to the Earth's land, oceans, and atmosphere. As the Earth rotates, the sun lights up only part of the Earth at a time, and some of that incoming solar energy is reflected and some is absorbed, depending on type of area it lights. The amount of reflection and absorption is critical to th e climate. An instrument named CERES orbits the Earth every 99 minutes and measures the reflected solar energy. This animation shows the scene identification as measured by CERES during 29 orbits on June 20 and 21 of 2003. By comparing the incoming solar radiation with the outgoing reflected and thermal radiation, it is possible to identify the type of area being viewed, whether it be land, clouds, ocean, or ice. This scene identification is used together with the radiation flux measurements to build up a complete picture of the Earth's energy budget over time.
GCMD keywords can be found on the Internet with the following citation:
Olsen, L.M., G. Major, K. Shein, J. Scialdone, S. Ritz, T. Stevens, M. Morahan, A. Aleman, R. Vogel, S. Leicester, H. Weir, M. Meaux, S. Grebas, C.Solomon, M. Holland, T. Northcutt, R. A. Restrepo, R. Bilodeau, 2013. NASA/Global Change Master Directory (GCMD) Earth Science Keywords. Version 220.127.116.11.0