Anders Moberg (2020) Stockholm Historical Weather Observations — Monthly mean air temperatures since 1756. Dataset version 2. Bolin Centre Database. https://doi.org/10.17043/stockholm-historical-monthly-temperature-2
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. https://doi.org/10.1023/A:1014966724670
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. https://doi.org/10.1002/joc.945
Moberg A, Tuomenvirta H, Nordli Ø. 2005: Recent climatic trends. In: Physical Geography of Fennoscandia. (Ed: Seppälä M). Oxford Regional Environments Series, Oxford University Press, Oxford: 113–133
Data are provided in three files, one file for each variant of the data. The data are available both as comma-separated values (csv) and tab-separated values (tsv) files:
i: stockholm_monthly_mean_temperature_1756_2019_nonhom.csv (and *.tsv)
ii: stockholm_monthly_mean_temperature_1756_2019_homo.csv (and *.tsv)
iii: stockholm_monthly_mean_temperature_1756_2019_adjust.csv (and *.tsv)
Each data file has 18 columns with the following headers: year, jan, feb, mar, may, jun, jul, aug, sep, nov, dec, djf, mam, jja, son, ann.
Column 1: Year.
Column 2–13: Monthly mean temperature for January through December.
Column 14: December to February mean temperature, assigned to the year in which January falls.
Column 15: March to May mean temperature.
Column 16: June to August mean temperature.
Column 17: September to November mean temperature.
Column 18: Annual mean temperature.
Temperature unit: °C rounded to one decimal.
Code for missing DJF value in year 1756: −999.0.
The observation site is included in the national station network managed by the Swedish Meteorological and Hydrological Institute (SMHI), with station number 98210 (manual station) and 98230 (automatic station).
The three variants of monthly mean air temperatures are derived from the associated dataset with daily mean temperatures.
The first variant (non-homogenized data, see Moberg et al. 2002) accounts for changes in observation times and also includes the following adjustments:
1. Data for some periods in 1756 and 1763 have been replaced with estimated temperatures derived from contemporaneous observations in Uppsala, to adjust for missing or poor daily observations in Stockholm.
2. Adjustment in 1819– 1825 for an incorrectly calibrated thermometer probably being used.
Note: In the corresponding dataset with daily mean temperatures, these two particular adjustments are not applied to the non-homogenized data, but they are applied there to the homogenized data. The motivation for applying these corrections to the non-homogenized data here is to provide a temperature record that represents the actual temperature history, including the urban warming trend but with corrections made for the supposed unreliable data in short periods in 1756, 1763 and 1819– 1825.
The second variant (homogenized data, see Moberg et al. 2002) additionally includes an adjustment after 1870 to eliminate an urban warming trend and the effect of other inhomogeneities detected in homogeneity tests against surrounding reference station data. The main purpose of applying this adjustment is to obtain a homogenized record that, throughout its entire length, is approximately respresentative of the rural conditions that prevailed before the mid–19th century. The size of the adjustment changes with time and varies over the year. It causes homogenized temperature data after 1967 being on average 0.8°C colder than non-homogenized temperatures.
The third variant (homogenized data, with additional adjustment to data for May – August in the period 1756–1858), has been derived as in Moberg et al. (2005) based on conclusions in Moberg et al. (2003). It includes the following additional adjustments, relative to the second variant:
May and August: −0.3 °C.
June and July: −0.7 °C.
The motivation for this additional adjustment is based on the available knowledge about the position of the old thermometer in combination with results from homogeneity testing and other statistical modelling. However, it should be seen as an ad hoc judgement rather than a result from a strict statistical analysis. Nevertheless, this variant of daily mean temperatures is judged to be the one that currently best represents the true temperature climatology for the May– August season. Further research would be needed to better assess the need for adjustments in the early period and to determine their size and how they should be applied. There is a need also to undertake further analysis of how to better adjust the temperature data for the modern urban heat island effect, because the current adjustment is based on results from a study made in the late 1990s.
Data from before 2013 are based on manual observations (SMHI station 98210). Data from 2013 onward are derived from the automatic weather station (SMHI station 98230). Monthly mean temperatures presented here may differ from those that can be obtained directly from the SMHI due to differences in calculation procedures.
A few monthly and annual mean temperature values in this version of the dataset differ by 0.1 °C compared to earlier versions in this repository because all averages have now been re-calculated from the daily mean temperatures. This has led to some differences while rounding the temperature values to one decimal place.
Further information about instrument positions and original data sources is available in the comments to the associated dataset with thermometer observations.
+46-8-674 78 14
Department of Physical Geography, Stockholm University
SE-106 91 Stockholm
Earth science > Atmosphere > Atmospheric temperature > Surface temperature > Air temperature
Continent > Europe > Northern Europe > Scandinavia > Sweden
Digitization, quality control and development of daily and monthly air temperature and pressure data series until 1998 was undertaken as part of the project IMPROVE — Improved Understanding of Past Climatic Variability from Early Daily European Instrumental Sources. Project funding: EU 4th Framework Programme, 1998–1999. Contract: ENV4-CT97-0511. Co-ordinator: Dario Camuffo, Consiglio Nazionale delle Ricerche, Istituto di Scienze dell'Atmosfera e del Clima, Padova, Italy. PI at Stockholm University: Anders Moberg. Later updates of the data have been made by Anders Moberg without any further dedicated funding.
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