The Earth’s Radiation Budget/shortwave radiation/longwave radiation
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The Earth’s Radiation Budget
The Earth’s radiation budget involves the energy entering, reflected, absorbed, and emitted by the Earth system. Based on conservation of energy, it shows the balance between incoming solar radiation and outgoing radiation, which includes reflected solar radiation and emitted Earth system radiation. An imbalance in this budget can change the atmosphere’s temperature and affect the climate. Energy is measured in watts per square meter (W/m2).
INCOMING SOLAR RADIATION
Incoming solar energy includes ultraviolet, visible, and some infrared energy, known as “shortwave radiation.” This energy drives the Earth’s climate. Some is reflected by clouds, some is absorbed by the atmosphere, and some reaches the Earth’s surface. Aerosol particles in the atmosphere absorb some radiation, warming the atmosphere. This heat is emitted as longwave infrared radiation, with some radiating into space.
ABSORBED ENERGY
Solar radiation that passes through the atmosphere is either reflected by surfaces like snow and ice (albedo effect) or absorbed by the Earth’s surface.
Emitted LONGWAVE Radiation
The heat from absorbed shortwave radiation is emitted as longwave radiation. Radiation from the upper atmosphere and the Earth’s surface radiates into space. Most emitted longwave radiation warms the lower atmosphere, which then warms the Earth’s surface.

GREENHOUSE EFFECT

Greenhouse gases like water vapor and carbon dioxide absorb most of the Earth’s emitted longwave radiation, heating the lower atmosphere. This warmed atmosphere emits longwave radiation back to the Earth’s surface, keeping it warm. Higher greenhouse gas concentrations increase lower atmosphere temperatures by trapping emitted radiation, leading to global warming and climate change.

Scientists must understand changes in the Earth’s radiation budget to study climate change.

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