Average Total-sky Incoming Solar Flux (WMS)

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 average amount of reflection and absorption is critical to the climate, because the absorbed energy heats up the Earth until it is radiated away as thermal radiation. This animation shows the monthly average incoming solar radiation from July, 2002 through June, 2004 as measured by the CERES instrument. This average data set is constant in longitude because of the Earth's rotation, but clearly shows the seasonal cycle as the sun heats the Northern Hemisphere more in summer than in winter. Note that the polar regions are abnormally bright in the local summer and dark in the local winter because whole day is either light or dark in those seasons.

See http://asd-www.larc.nasa.gov/ceres/ASDceres.html