Energy Inequalities, Earth's Atmosphere and Storms

Question

How do energy inequalities occur? What are the results relative to the circulation of the atmosphere? What are storms overall, and why are they an important part of Earth’s atmosphere system?

Answer 1

Solar energy, via radiation, drives the winds that blow across our planet and these winds drive Earth’s ocean and air currents. Because of Earth’s rotation, its elliptical orbit, its spherical shape and the inclination of Earth’s axis at 23.5 °, the solar radiation that strikes the surface is uneven and therefore heats the planet unevenly. The winds that blow are an attempt to move heat from the equator (or tropics) -- where the sun’s angle is most direct -- to the poles to re-distribute this heat energy in the atmosphere to balance energy around the earth. During the equinoxes, sun’s angle is more indirect Tropic of Cancer (23.5° north) or the Tropic of Capricorn (23.5° south), solar radiation is less intense than at the equator. Where weather is created, there are low pressure systems in place and the winds are not only an attempt to equalize energy imbalances but also to equalize pressure imbalances (Lutgens & Tarbuck, 2017). For example, low pressure systems may be characterized by storms.

Storms are caused by the presence of unstable air that rises in the atmosphere. Air that is stable does not rise. Because of surface heating from the sun, air warms and rises via updrafts. These updrafts lift parcels of this warmed air which picks up moisture on its journey upward into the atmosphere. The now warm air parcel that’s saturated with moisture forms cumulonimbus clouds. The point at which cloud formation occurs is called the lifting condensation level (LCL). Updrafts will continue to lift warm air until there is too much moisture contained within the cloud at which point the cloud releases its precipitation. Uplift of air parcels will also cease if updrafts cease. The other mechanism that may occur is the presence of downdrafts in clouds which overpower the updrafts. When downdrafts overpower updrafts, the storm ceases. During updrafts, Earth’s surface and the troposphere will become windy. As the cloud releases precipitation, a cooling effect occurs and along with the downdrafts, the storm ceases – unless the storm continues to travel where it will pick up more warm, unstable air (Lutgens & Tarbuck, 2017). Storms are important to the atmosphere because both winds and storms are attempts to equalize energy and pressure in low pressure regions.

References

Lutgens, F. K., Tarbuck, E. J., & Tasa, D. (2017). Foundations of earth science. Boston: Pearson.