The Earth’s radiation budget accounts for the balance of incoming shortwave (SW) radiation from the Sun and longwave (LW) radiation exiting from the Earth-atmosphere system at various time and space scales.

When incoming shortwave solar radiation, known as insolation, enters the Earth’s climate system, a portion of it is absorbed at the Earth’s surface, causing the surface to heat up and a portion is reflected back to space as outgoing shortwave radiation. Some of the absorbed energy is then radiated outward in the form of longwave infrared radiation. Cloud layers trap some of the radiation from the Earth’s surface, and then emit longwave radiation, both out to space and back to the surface.