Energy Transfer in the Atmosphere Chapter 4.2-4.3

Energy From the Sun Sun’s energy travels 148 million km to Earth in 8 minutes. It reaches the Earth through a process of radiation. Radiation is the transfer of energy by electromagnetic waves. 99% of the radiant energy from the sun consists of visible light, ultraviolet light, and infrared radiation.

Energy on Earth Not all of the energy coming from the sun reaches the surface of the Earth. Absorption takes place and takes up 20% of the incoming solar radiation. Oxygen, ozone, and water vapor absorb UV light Water and Carbon Dioxide in the troposphere absorb some infrared radiation Reflection takes place on bright surfaces like clouds and they reflect about 30% of the sun’s radiation In total about 50% of the sun’s radiation is hitting the surface of the Earth.

Radiation Balance If the sun continuously sends radiation to Earth, why doesn’t the Earth get hotter and hotter? The radiation that is absorbed by organisms and the Earth’s surface are reradiated back into the atmosphere.

The Greenhouse Effect Greenhouse gases keep some of the reflected radiation from escaping back into the atmosphere. They direct it back to Earth’s surface. This causes additional heat to build up at Earth’s surface. Leads to Global Warming Rising Temperatures More Powerful Storms

Thermal Energy Transfer Thermal Energy always moves from an object with a higher temperature to an object with a lower temperature. Conduction- The transfer of thermal energy by collisions between particles of matter. Convection- The transfer of thermal energy by the movement of particles within the matter

Circulating Air Energy is transferred through the atmosphere by convection. Hot air rises and cold air sinks. Air is constantly moving up and down making a “mountain wave”

Stability Describes whether circulating air motions will be strong or weak. When air is unstable the circulating motions are strong. When it’s stable, circulation is weak.

Stability Unstable conditions are normally on warm, sunny afternoons. They cause tall clouds because of the rapid air rising and sinking. Latent heat is released as water vapor which adds instability and creates thunderstorms.

Stability When ground air is the same temperature as higher-altitude air, the air is stable. In these conditions we could have a temperature inversion (occurs in the troposphere when temperature increases as altitude increases)