Air temperature data for Godthåb (now Nuuk) in SW Greenland at the beginning of the 19th century (1st Nov 1806 to 16th August 1813)

The database contains results of meteorological measurements in SW Greenland (Godthåb [now Nuuk]) at the beginning of the 19th century (1st Nov 1806 to 16th August 1813).The data were taken from the manuscript (MA/154) found in the Archives of the Royal Society in London. The meteorological observations were carried out by the German mineralogist Dr Charles Lewis Giesecke (born Johann Georg Metzler, [1761–1833]). The following meteorological variables are available: atmospheric pressure (morning and evening), air temperature (morning, midday, and evening), and wind direction (morning and evening). The detailed hours of observations are not known. The database contains both the source data digitised from the meteorological register as well as calculated mean daily air temperature (MDAT) using a weighted average: (Tmorning + Tmidday + 2 × Tevening) / 4. To check the probable biases in the calculation of MDATs, we assessed them using hourly air temperature data taken from the Nuuk station from 2010 to 2020. Analysis shows that in the cold half-year (Oct-Mar), the maximum bias reaches 0.1°C, while in summer it is the highest but does not exceed 0.5°C (for more details, see the paper Przybylak et al. 2025, Climate of the Past, Preprint, https://doi.org/10.5194/egusphere-2025-4313). The gaps for September 1807 (in brackets) were filled using data from the same days of the year, but from the years 1808–12. These data were used to calculate the differences between noon/evening observations and morning observations—for which data from September 1807 are available. The resulting five-year average differences were added to the morning observation data from the period of September 20–30, 1807. On the other hand, missing data from September 18 and 19 were reconstructed using average values calculated from ten temperature values measured at the same observation time on adjacent days.