The Earths Heat Engine

The weather and climate of the Earth are primarily controlled by the energy from the sun. Large amounts of solar radiation are received in the equatorial regions and much of this energy is then transported by the atmosphere and the oceans to the middle and high latitudes, where it is lost as infrared or heat radiation back into space. This system, which keeps the equatorial regions from overheating and the polar regions from continuously cooling, is sometimes called the Earth's "heat engine," with the low latitudes acting as a heat source and the high latitudes as heat sinks.

The transfer of heat from the equator to the poles takes place within the atmosphere and the oceans. The horizontal transport (advection of heat) in the atmosphere occurs in the form of both latent heat (i.e., water vapor that subsequently condenses) and sensible heat (warm air or warm water masses). It varies in intensity according to latitude and season. The intensity of the poleward energy flow is closely related to the meridional (north-south) temperature gradient. In winter, this temperature gradient is at a maximum and in consequence the atmospheric circulation is most intense. Different air masses form, which have different characteristics and are separated from one another by fronts (sharp discontinuities in temperature, moisture, and wind speeds). The movement of these air masses transfers heat and moisture and is part of the general global atmospheric circulation. Similarly, different water masses, such as the Gulf Stream and other current systems, are part of this global heat transfer system.

The nature and conditions of the surface of the Arctic, including the presence of snow and ice for much of the year, further modify the climate through the regional heat energy balance. The available heat energy is distributed to warm the air or the ground, melt snow and ice, or evaporate water from the surface. Stable surface inversions (in which air temperature increases with height) form over most of the Arctic terrain and are caused by radiative cooling of the surface (loss of heat by infrared radiation), particularly in winter. Intense cold periods result through the combined effect of radiative cooling at the surface and anticyclonic conditions with clear skies. During summer, the temperature of the entire pack ice of the Arctic Ocean remains at 0°C and there are large stretches of open water. Fog and low stratus clouds are produced by the ice and open water, persisting throughout the summer in spite of changes in atmospheric circulation. Away from the coast and the chilling influence of the coastal waters, temperatures are much warmer, leading to a much more diverse flora.

Was this article helpful?

0 0
Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

Get My Free Ebook

Post a comment