Below is a report by Alex Kirby of Climate News Network, setting out the research done by the Radcliffe Meteorological Station, based at Oxford University’s Green Templeton College and maintained by the university’s School of Geography and the Environment. Scientists there have access to weather records dating back to 1767.
Oxford has been at particular risk of flooding over the last decade. The city sits in a narrow valley alongside the River Thames. Heavy rainfall in areas further upstream, such as the Cotswolds, will invariably pose a flood risk in parts of Oxford as the levels of the River Thames rise. The valley is especially narrow near the south of the city, making this area at particular risk of flooding.
Report by Alex Kirby, Climate New Netowrk
LONDON, 8 October, 2014 – Several parts of the world like to claim that their unpredictable weather allows you to experience spring, summer, autumn and winter in the space of a single day. The city of Oxford, in the English Midlands, cannot make that boast, but it has broken a surprising number of weather records in a fairly short time.
In its latest bout of meteorological exuberance, Oxford has just had its second driest September since records began almost 250 years ago. It recorded 4.1mm of rainfall over last month, with 1929 the only previous year to have had a month with a lower total − just 2.5mm.
This follows hard on the heels (climatically speaking, at least) of the first month of 2014, which was, by contrast, the wettest January the city has recorded, with total rainfall of 146.9 mm − almost three times the normal and 35 times September’s paltry figure.
Go back a little further, though, for wet weather that really meant business: the nine months from 1 April to 31 December 2012 proved the rainiest nine-month stretch in Oxford’s recorded experience.
Yet the people of Oxford might at that point have been lulled into expectations of balmier weather, because 2011 had turned out to be the city’s joint second-warmest year on record. Six of the top 10 warmest years recorded have occurred since 2000, the warmest being 2006.
Oxford, home of the oldest university in the English-speaking world, knows the details of its weather peaks and troughs so well because it possesses a unique archive.
The Radcliffe Meteorological Station, based at Oxford University’s Green Templeton College and maintained by the university’s School of Geography and the Environment, holds the longest series of temperature and rainfall records for one site in Britain, with records dating back to 1767.
Of nearly 3,000 monthly records since Oxford’s measurements began, only 30 have been drier than last month. This puts September 2014 in the top 1% of the city’s driest ever months.
Dr Ian Ashpole, who collects the daily measurements for Radcliffe, said of the latest record to fall: “Based on analysis of variability around the mean September rainfall over the last 248 years, we can say that no Septembers since 2000 have been unusually wet, but three have been unusually dry.”
Only one of the other 30 driest months has occurred in the autumn (September to November); 14 have been in spring (March to May), eight in summer (June to August), and the remaining seven during the winter. Four of the driest months have occurred this century.
This year’s September record may be part of an emerging trend in the month since 2000. The 248-year long-term average for September is 60mm, but since the turn of the century 12 have been below this average, including six under 50% of expected rainfall. Only two years have been above the 60mm average − 2008 (72.9mm) and 2006 (90.8mm).
September 2014’s temperature was not quite as extreme as the low rainfall, but still came in at equal seventh (with 1998) at 15.9°C, compared with the long-term average of 13.7°C. Five of the warmest eight Septembers since 1767 have been recorded since 1998.
However, the data from Radcliffe applies only to the city of Oxford and a short distance around it, and can tell us nothing about weather elsewhere in the UK or further afield. – Climate News Network