http://www.bath.ac.uk/pr/releases/antarcticradar.htm

Scientists use meteors to investigate climate change and giant
waves at the 'edge of space'

University of Bath
News Release
May 23, 2005

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.

The new radar base at the Rothera research station in the AntarcticThey
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.

"Fortunately, nature provides us with an excellent answer to the
problem
of investigating the mesosphere," said Professor Nick Mitchell who
heads
the project in the Department of Electronic and Electrical Engineering
at the University of Bath.

"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
one day and with this information study the waves and tides that flow
around the planet on a continuous basis.

"The mesosphere has been called the miner's canary for climate change;
meaning that it is very sensitive and the changes there may be larger
than in any other part of the atmosphere.

"Evidence of these changes comes from sightings of noctilucent clouds,
very unusual clouds seen only in polar regions and known to be in the
mesosphere. These clouds don't seem to have been observed before 1885
and may mark the onset of a long-term cooling of the upper atmosphere".

The researchers hope to use this temperature data to see if the effects
of climate change are present in the upper atmosphere.

The radar is the latest element in a global array of radars being
installed by the University of Bath group. It will be used in tandem
with an identical radar at Kiruna, inside the Arctic Circle in Northern
Sweden, to find out if there are any differences between the Arctic and
Antarctic upper atmosphere.

"We know that there are big differences lower down in the atmosphere,
for instance in the stratosphere the ozone hole is much larger over the
Antarctic than over the Arctic, but we don't really know what the
differences are like higher up," said Professor Mitchell.

Dr Pete Younger installing the new radarFirst results from the radar
show that it is detecting about 5,000 meteors ever day. Analysis at the
University of Bath has revealed frigid temperatures in the mesosphere,
the lowest temperatures of about -130?C, paradoxically occurring at
midsummer.

The Rothera radar has been installed by Dr Peter Younger, a
postdoctoral
researcher from the University assisted by colleagues from BAS.

The radar is made of six antennas about 2 metres high set up over a
space the size of a football pitch. The site itself is a rocky beach on
the edge of Marguerite Bay - a landscape of icebergs, penguins and
seals. Dr Younger has just returned to the UK having spent two months
on
the installation.

Ends