The turbopause, also known as the homopause, marks the altitude in an atmosphere below which turbulent mixing dominates. Mathematically, it is defined as the point where the coefficient of Eddy diffusion is equal to the coefficient of

molecular diffusion Molecular diffusion, often simply called diffusion, is the thermal motion of all (liquid or gas) particles at temperatures above absolute zero. The rate of this movement is a function of temperature, viscosity of the fluid and the size (mass) of ...

. The region below the turbopause is known as the homosphere, where the atmosphere is well mixed for chemical species which have long mean residence times. Highly reactive chemicals tend to have variable concentration throughout the atmosphere, while unreactive species have more homogeneous concentrations. The region above the turbopause is the heterosphere, where

dominates and the chemical composition of the atmosphere varies according to chemical species and their atomic weight. The Earth's turbopause lies near the

mesopause The mesopause is the point of minimum temperature at the boundary between the mesosphere and the thermosphere atmospheric regions. Due to the lack of solar heating and very strong radiative cooling from carbon dioxide, the mesosphere is the cold ...

, at the intersection of the

mesosphere The mesosphere (; ) is the third layer of the atmosphere, directly above the stratosphere and directly below the thermosphere. In the mesosphere, temperature decreases as altitude increases. This characteristic is used to define its limits: it ...

and the

thermosphere The thermosphere is the layer in the Earth's atmosphere directly above the mesosphere and below the exosphere. Within this layer of the atmosphere, ultraviolet radiation causes photoionization/photodissociation of molecules, creating ions; the ...

, at an altitude of roughly 90 km (56 mi). Some other turbopauses in the solar system that are known include Venus' turbopause at about 130 – 135 km, Mars' at about 130 km, Jupiter's at roughly 385 km, and Titan's at around 800 – 850 km. It was discovered by

French French (french: français(e), link=no) may refer to: * Something of, from, or related to France ** French language, which originated in France, and its various dialects and accents ** French people, a nation and ethnic group identified with Franc ...

scientists following the firing of two Véronique sounding rockets March 10th and 12th, 1959.

References

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