Northern Lights shift further northward
Release date: August 09, 2005
 A
remarkable diary of an 18th Century Gloucestershire apothecary has
yielded new scientific information on the upper atmosphere – namely that
the Aurora Borealis, or Northern Lights as they are popularly known,
have moved north over the last two centuries.
The diary of Thomas Hughes was known for its records of rainfall and
temperature in his home town of Stroud, but a chance examination of the
diary led Dr Giles Harrison, an atmospheric scientist in the Department
of Meteorology, to realise that it also contained records of the aurora
borealis.
"As well as the meteorological records, Hughes’ diary was just full of
other carefully-observed scientific material," said Dr Harrison. "It
mentioned eclipses, an earthquake and an outbreak of smallpox. But I
also noticed that it frequently contained the abbreviation ‘AB’, which
indicated that he had observed the Aurora Borealis."
Comparing the 71 dates on which Hughes’ diary reported an aurora
borealis between 1771 and 1813, Dr Harrison found that many coincided
with established European auroral sightings. Dr Harrison studied the
number of aurorae in different months, and found a pattern now
characteristic of locations further north than Stroud. From this he
deduced that the area in which the aurora can be seen – the auroral zone
– has moved north since Hughes’ time.
Dr Harrison said: "I was initially astonished that aurorae were visible
on so many nights in a southerly part of the UK. Although light
pollution often prevents aurora being seen there now, I wondered if the
location of the auroral zone itself might also have changed. Hughes’
diligent observations show that it has."
The work is reported in the August edition of Astronomy and
Geophysics, published by the Royal Astronomical Society.
end
Notes for Editors
• Aurora produce intricate blue or green patterns in the night sky at
heights of 80 to 100km, well above clouds. The aurora borealis can
sometimes be seen on clear nights in the northern UK and Scandinavia.
Aurorae in the southern part of the UK are rare.
• Knowledge of the aurora provides scientists with information about the
activity of the sun, and the Earth’s magnetic field. Changes in the sun
have been suggested to produce small changes in weather and climate.
• Thomas Hughes’ diary belongs to the Royal Meteorological Society. It
consists of three bound volumes, kept by the National Meteorological
Archive in Exeter.
• Dr Giles Harrison is Senior Lecturer in Atmospheric Physics at the
Department of Meteorology, The University of Reading, a world-leading
centre of excellence in the atmospheric sciences. For more information
see: http://www.met.rdg.ac.uk.
Contact
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press officer.
T: 0118 378 7388
E: c.hillsley@rdg.ac.uk |