in the Atmospheric Physics group at the Stockholm University
Between 70 and 100 km, the Earth's atmosphere maintains a delicate balance between the Sun's radiative forcing from above, and the action of atmospheric waves rising up from below. As a result, this region, kown as the mesosphere and lower thermosphere, displays large variations in temperature, density and composition associated with changes in the solar or wave forcing. However, this atmospheric region is also where the effects of global climatic change associated with human activity may be largest. Thus, these natural fluctuations may mask the evidence of secular change in climatological measurements of the temperature, density and winds of the middle and upper atmosphere.
In order to characterse these naturally occuring variations and to search
for secular trends associated with human activity, the Atmospheric Physics
group at Stockholm University is working with ground-based spectroscopic
measurements of the Earth's
airglow, the radiation that results from
chemical reactions taking place high (87 to 97 km) in the atmosphere.
Since these chemical reactions occur over a very limited altitude range
for each atmospheric species, the resulting radiation carries with it the
information about the temperature, wind and species concentration at that
altitude. Thus, by observing spectra of airglow emissions from atomic oxygen,
hydroxyl radicals, and molecular oxygen, one may remotely sense the wind
and temperature of the middle and upper atmosphere.
This link will bring you to a short paper explaining the measurements and giving the results to date.
This link will bring you to the atmospheric physics group and gives you the possibility to look at some other projects on which we are working. These include rocket experiments and a satellite called ODIN which will be launched 1998.
Instrument details and summary plots of the data are available here.
This link will take you to the PSMOS Home Page.