“I AM a definite cloudwatcher,” said Gaynor Boon, as a series of stratocumulus layers drifted above her in Weston Park.
“Watching the clouds is like watching actors on a stage, playing out the drama of the British weather.”
Gaynor has been watching - and monitoring - Sheffield’s weather for 25 years, until recently as earth sciences curator at Weston Park Museum.
As the clouds sweep over, usually from the west, she and her colleagues (and predecessors) have been recording Sheffield’s weather at the Weston Park weather station since 1882, following a recommendation by the public health board of the time to set up accurate monitoring of ‘atmospherical returns’ in the city to help research into diseases such as summer diarrhoea, which had killed many local children in 1880.
This year, Gaynor and researcher Adrian Middleton have released a book through the Sorby Natural History Society, titled ‘Sheffield’s Weather.’
It covers a history of weather recording in Sheffield, the causes of the city’s weather patterns, the changes observed over recent years, and a comprehensive collection of weather related incidents collected from local diaries, journals and newspapers.
These include the observations of ‘gentlemen scientists’ such as Dr Thomas Short, who linked weather to bouts of toothache and rheumatism, and White Watson, who in his diaries claimed to have been struck by lightning three times, once while at dinner.
Records of 1615 spoke of ‘ye greatest snow which ever fell on earth within man’s memorye,’ and during the snowfall in December 1726 there was casual mention of the people who had ‘lost their lives in going from Sheffield to Hathersage’. There are several mentions of death by lightning of horses, riders and cattle, and in the latter case, the milkmaid who was deprived of speech and left dumb thereafter by ‘the electric fluid.’
Adrian Middleton was impressed by the accounts of the 18th and 19th century recorders.
“The history is fascinating as it illustrates the development of scientific thought,” he said. “There are articles about why clouds stay in the sky, for example. Science then was about knowledge of the world, and weather was part of the world but like other acts of God, it was often a mystery.”
The daily collection of temperature, rainfall, wind, pressure and sunlight data at Weston Park is now part of the national (and international) data used for scientific analysis of the weather, and the Sheffield records have been praised by the likes of the Royal Meteorological Society for their consistency. They have also fed into local and national studies of climate change, and local adaptation plans for the different weather patterns we can expect in future.
“Since 1990, temperatures have risen by about a degree,” said Gaynor. “There has never been such a sustained growth as over the last 20 years.”
One of the most noticeable changes has been the increase in sunshine.
“We now get on average about 250 more hours of sunshine every year than 20 years ago,” said Adrian, “so that’s almost an hour a day.”
The national graphs in their book show the changes very visibly, with marked changes in temperature, rain, frost, lying snow and more on a line across the centre of England.
Gaynor stressed that changing global weather patterns will have complex effects, with changes in sea temperature potentially leading to changes in Sheffield, including more weather from the East.
“We had some warning signs with the floods of 2007, we’ve see what can happen,” she said. “The summer weather is more erratic and extreme, and with great quantities of rain and the nature of our topography, those moorland rivers are going to empty into the Sheaf and the Don and we need to be prepared for it.”
Sheffield’s weather is generally quite complicated, said Gaynor, with ‘micro-climates’ around our hills and valleys, and an ‘urban heat island’ in the city centre, (which, along with the reduction of industrial pollution, is the cause of the marked reduction in fog over recent years).
But a very rough snapshot of Sheffield’s weather is of a city influenced by the Pennines and being equidistant from the East and West coasts, said Gaynor, with the chief influence being the low pressure fronts arriving over the Pennines.
“We get what rain is left after the Welsh mountains and the Pennine moors. After it’s passed over Sheffield’s western suburbs, by the time it’s got to us in Weston Park it’s often fizzled out.
“But we’re also affected by anticyclones which drift over from Scandinavia and lodge over us in the summer and winter. They’re stable, and often sit there for a long time. They may bring in a blanket of cloud which can can sit there for days, or it could mean days of glorious sunshine. They can also lead to asthma problems when pollutants get trapped in.”
The other complications are wet Western fronts that swirl around over France and arrive to us from the East, and then get trapped by the Pennines - like the systems leading to the floods of 2007.
Gaynor and Adrian are cautious about the debate over climate change, and said their book presents the data rather than interpreting it.
They note, however, that the science is clear on the issue.
“The scientific community are firm that the data shows that global temperatures are related to man-made CO2,” said Adrian. “As far as I’m concerned that’s straightforward.”
“The graphs show climate changing in Sheffield,” said Gaynor. “Being out personally recording the weather day in day out for 24 years, I’ve seen the changes. We are lucky to have a long range weather station here, and it shows that the same trend scientists have been pointing out for the country and the planet is happening here in Sheffield. I’d say to local people, come and see for yourselves, you can see it on the museum displays and in the book, it’s happening on your doorstep.”
lSheffield’s Weather is available from : www.sorby.org.uk