Homogenized daily mean temperatures
Daily mean temperatures for Stockholm, back to 1 January 1756, were calculated by Moberg et al. (2002). This work was undertaken within the European Union FP4 project IMPROVE - Improved Understanding of Past Climatic Variability from Early Daily European Instrumental Sources. Updates to the present is made by merging with the recent observations made by the SMHI. Daily mean temperatures are available in three variants:
- Daily mean temperatures as calculated directly from the observations at the Stockholm observatory, but with account taken for changes in observation hours.
- Daily mean temperatures as in (1), but with additional homogeneity adjustments and with some gaps (in 1756 and 1763) infilled through extrapolation from temperatures measured in Uppsala. The homogeneity adjustments account for the urban warming trend and for an incorrectly calibrated thermometer used 1819-1825.
- Daily mean temperatures as in (2), but with an additional adjustment from May to August 1756-1858 to account for supposed too high observed temperatures due to poorly sheltered thermometers (see Moberg et al. 2003).
Some more explanations of the various adjustments are found here.
- Moberg A, Bergström H, Ruiz Krigsman J, Svanered O. 2002: Daily air temperature and pressure series for Stockholm (1756-1998). Climatic Change 53: 171-212
- Moberg A, Bergström H, Ruiz Krigsman J, Svanered O. 2002: Erratum. Climatic Change 54: 249-250
- Moberg A, Alexandersson H, Bergström H, Jones PD. 2003: Were Southern Swedish summer temperatures before 1860 as warm as measured? Int. J. Climatol. 23: 1495-1521