A monthly temperature series for Durham from 1784
The geographer and climatologist Gordon Manley produced a monthly temperature reduction for Durham University Observatory from 1801 to extend the series back from the start of meteorological observations at the Observatory in the 1840s. He produced his extended series shortly before he died in 1980, and left it in a provisional state, with limited notes regarding his construction of the monthly means based on temperature observations from sites around the North East of England. Papers that Manley left have been examined to ascertain how he arrived at his reduction, and his methods have been fully documented and analysed. Errors in the derivation of his monthly means have been corrected, and methods that he used refined to improve their accuracy. New techniques for the reduction of means from archived data have been studied. A selection of these were implemented to improve the accuracy of the new series, and further temperature observations that Manley did not use in his version have been evaluated and introduced. Observations from South Cave, near Hull, from 1794, and from Brandsby, near York, from 1784, provide the extension of the record back from 1801. Substantial sets of monthly means from Braithwaite, near Keighley, and Jesmond, near Newcastle upon Tyne, in addition to shorter sets from other sites around the North East of England and the Borders, have been incorporated into the reduction from 1801 to improve the representativeness of Manley's series. The completed series, from January 1784, has been analysed and compared with other temperature series for the British Isles, and the potential for a daily version of the monthly series has been investigated, based upon the data sources currently available.