Energy and Matter: Shortwave Radiation (2012)
CERES (Clouds and the Earth's Radiant Energy System) is one of the highest priority scientific satellite instruments developed for NASA's Earth Observing System (EOS).
This global view shows CERES top-of-atmosphere (TOA) shortwave radiation from January 26 and 27, 2012. Light energy reflected from Earth (in Watts per square meter) is shown in shades of blue and white. The brightest-white areas (generally clouds) are reflecting the most energy out to space, while the darker blues areas reflect much less. Increasing cloud cover and snow/ice cover all tend to increase the ability of Earth to reflect energy out to space.
The Sun's radiant energy is the fuel that drives Earth's climate engine. The Earth-atmosphere system constantly adjusts to maintain a balance between the energy that reaches the Earth from the Sun and the energy that flows from Earth back out to space. Energy received from the Sun is mostly in the visible (or shortwave) part of the electromagnetic spectrum, where Earth's atmosphere is transparent. About 30% of the solar energy that comes to Earth is reflected back to space by clouds and aerosols or bright surfaces. The ratio of reflected-to-incoming energy is called "albedo" from the Latin word meaning whiteness. The solar radiation absorbed by the Earth causes the planet to heat up until it is radiating (or emitting) as much energy back into space as it absorbs from the Sun. The Earth's thermal emitted radiation is mostly in the infrared (or longwave) part of the spectrum, where Earth's atmosphere is not transparent. Thus, much of the emission to space is from the higher levels of the atmosphere. The balance between incoming and outgoing energy is called the Earth's radiation budget.
CERES products include both solar-reflected and Earth-emitted radiation from the top of the atmosphere to the Earth's surface. Cloud properties are determined using simultaneous measurements by other EOS and NPP instruments such as the Moderate Resolution Imaging Spectroradiometer (MODIS) and the Visible Infrared Imaging Radiometer Suite (VIIRS). Analyses using CERES data build upon the foundation laid by previous missions such as the NASA Earth Radiation Budget Experiment (ERBE), leading to a better understanding of the role of clouds and the energy cycle in global climate change.
For more information on the Clouds and Earth's Radiant Energy System (CERES) see http://ceres.larc.nasa.gov.
Credit: NASA Scientific Visualization Studio