Uncertainties in early Central England temperatures

Uncertainties in historical climate records constrain our understanding of natural variability of climate, but estimation of these uncertainties enables us to place recent climate events and extremes into a realistic historical perspective. Uncertainties in Central England temperature (CET) since 1878 have already been estimated; here we estimate uncertainties back to the start of the record in 1659, using Manley's publications and more recently developed techniques for estimating spatial sampling errors. Estimated monthly standard errors are of the order of 0.5 degrees C up to the 1720s, but 0.3 degrees C subsequently when more observing sites were used. Corresponding annual standard errors are up to nearly 0.4 degrees C in the earliest years but around 0.15 degrees C after the 1720s. Daily standard errors from 1772, when the daily series begins, up to 1877 are of the order of 1 degrees C because only a single site was used at any one time. Inter-diurnal variability in the daily CET record appears greater before 1878 than subsequently, partly because the sites were in the Midlands or southern England where day-to-day temperature variability exceeds that in the Lancashire part of Manley's CET. Copyright (C) 2009 Royal Meteorological Society