A new research radar based in Antarctica is giving scientists the chance to study the highest layer of the earth’s atmosphere at the very edge of space. Using the new radar, scientists will be able to investigate climate change and explore the theory that while the lower atmosphere is warming, the upper atmosphere is cooling by as much as 1 degree centigrade each year. They will also be able to find out more about the complex waves, tides and other mechanisms that link this region – known as the mesosphere – to the lower regions of the atmosphere. At heights of around 80-100km (50-62 miles) the mesosphere is notoriously difficult to investigate and is the least-explored part of the earth’s atmosphere.
The low air pressure at this altitude means that it is impossible to fly aircraft in the mesosphere and even the huge weather balloons that are used to measure stratospheric ozone cannot climb high enough to reach this altitude. Satellites begin to burn up when they enter the mesosphere, so the new radar – just installed at the Rothera research base in Antarctica in a joint project between the University of Bath and the British Antarctic Survey (BAS) – will help scientists explore the region using remote sensing.
“Meteors, or ‘shooting stars’, burn up in the mesosphere. The meteors drift just like weather balloons so we can use a radar on the Earth and bounce radio waves off the meteors to find how fast they are moving and so measure the winds at the edge of space.
The fading of the radio echoes from the meteors also lets us measure the temperature of the atmosphere. We can detect thousands of meteors in any day and with this information study the waves and tides that flow around the planet on a continuous basis.