The stratosphere (pronunciation [ ʃtrato… ] or [ strato… ]; from Latin strātum , "blanket" and ancient Greek σφαῖρα sphaîra, "sphere") is the second layer of the earth's atmosphere . It lies above the troposphere and is part of the homosphere .
In the troposphere, the air circulation with its adiabatic properties is decisive for the temperature curve. In the layers above, the importance of convection recedes and the radiation equilibrium is decisive.
In the stratosphere, the temperature increases on average with increasing altitude. This inverse (compared to the troposphere) temperature profile is mainly determined by the left hand in the stratosphere ozone causes the UV radiation from sunlight absorbed while electromagnetic radiation is converted into heat. The heating is strongest in the area of the ozone layer , where the temperature rises from approx. –60 ° C to just under 0 ° C. This area is the stratosphere in the narrower sense, above which the temperature drops again with altitude. But an adiabatic temperature drop is never reached again.
Due to the low temperature at the tropopause, atmospheric water vapor condenses there almost completely. Because of this, the stratospheric air above it is very dry. Weather phenomena can therefore hardly be observed in the stratosphere. Polar stratospheric clouds, as an exception, only form under the extremely cold conditions of the polar night . Glowing night clouds even over the stratosphere in the mesosphere are another exception.
The presence of a temperature inversion and thus of the stratosphere was published - as was the tropopause - in 1902 by the French meteorologist Léon-Philippe Teisserenc de Bort and the German Richard Assmann .
Nowadays it is investigated with research aircraft like the Myasishchev M-55 "Geophysika" or the "ER-2" special version of the Lockheed U-2 . Since the end of July 2010 the HALO stationed in Oberpfaffenhofen , a development based on the Gulfstream G550 , has also been flying scientific flights.
In 2010 the Cranfield Astrobiological Stratospheric Sampling Experiment (CASS-E) was started, which uses a balloon probe to collect samples from the stratosphere, which are then examined for possibly existing extraterrestrial microorganisms .
Stratosphere in the broader sense
According to the radiation transport equation , the outer layer of every gas envelope (sun, Venus, Earth, Mars) is a stratosphere in the broader sense, which can be divided into further floors. Karl Schwarzschild recognized this storey structure of atmospheres as early as 1906 .
- David DeVorkin: Race to the Stratosphere. Manned Scientific Ballooning in America. Springer, Berlin 1989, ISBN 3-540-96953-5 .
- Karin Labitzke : The stratosphere. Springer, Berlin 1998, ISBN 3-540-65000-8 .
- Max Mangold, Paul Grebe: The Great Duden, Volume 6, pronunciation dictionary . Mannheim: Bibliographisches Institut, 1962, p. 712.
- Mission to search for alien life in outer atmosphere telegraph.co.uk, October 2, 2010; Cranfield Astrobiological Stratospheric Sampling Experiment (accessed October 5, 2010).
- Karl Schwarzschild: About the equilibrium of the solar atmosphere ( Memento from January 6, 2012 in the Internet Archive ) (PDF; 727 kB). In: News from the Society of Science in Göttingen, Mathematical-Physical Class. 1906, pp. 41-53.