The BAS findings give global significance to similar effects observed recently over Europe by other researchers. It is the hottest, windiest part of the Earth's environmental envelope with temperatures changing dramatically in the course of a day. Whilst at ground level temperature changes are relatively small, in the thermosphere they are up to 100 times greater.
Scientists can, therefore, use the region as a sensitive 'litmus paper' for detecting global change.
The ionosphere, which is a layer within the thermosphere, is one of the least explored and least understood parts of the Earth's atmosphere. Since 1958 BAS researchers have monitored changes in the upper atmosphere by using the ionosphere as a 'tracer'. Radio wave pulses are bounced off the ionosphere from study sites on the Antarctic Peninsula and the Falkland Islands. This latest discovery was made from analysis of over 600,000 film records of echo-sounding signatures collected by scientists from BAS and the Rutherford Appleton Laboratory. Atmospheric pressure controls the altitude of the ionosphere.