Available potential energy
Available potential energy (APE) is a quantity first derived in Edward Lorenz in1955 in an investigation to discover what portion of total potential energy could be transformed into kinetic energy under the constraint of quasi–hydrostatic and adiabatic processes. Available potential energy (APE) was defined as the difference between a system’s mass integrated total potential energy and the total potential energy of a hydrostatic reference state, i.e. the difference in potential energy between the actual physical state and the reference state, where the latter is defined as the state of minimum potential energy that can be reached through reversible adiabatic processes. In the reference state, all density surfaces are level. This was extended in Van Mieghem [1956] to deal with non–hydrostatic states.
Meteorology
In the field of atmospheric meteorology, the term convective available potential energy is invoked to indicate the is the energy content of air parcel, if that parcel were elevated to a certain altitude in the atmosphere (Atmosphere layers). The meteorological unit most commonly utilized is Joules per cubic meter. The existence of a positive value for the convective available potential energy is an indicator of vertical instability in the lower atmosphere, and can be a good predictor of thunderstorm activity.
Further Reading
- R. O. Reid, B. A. Elliott, and D. B. Olson. Available potential energy: a clarification. JPO, 11:15–29, 1981.
- A. H. Oort, S. C. Ascher, S. Levitus, and J. P. Peixoto. New estimates of the available potential energy in the world ocean. JGR, 94:3187–3200, 1989.
- Fred Kucharski. On the concept of exergy and available potential energy. Q. J. R. Meteorol. Soc., 123: 2141–2156, 1997.
- R. X. Huang. Mixing and available potential energy in a boussinesq ocean. JPO, 28:669–678, 1998.
- J. Van Mieghem. The energy available in the atmosphere for conversion into kinetic energy. Beitr. Phys. Atmos., 29:129–142, 1956.
