In Belgium, the deployment of a climatological network dates back to the 1870s. Since 1880, regular observations of temperature and precipitation have been available at various locations across the country. These observation records are extremely valuable to analyse the climate evolution. However, climatological time series are often affected by non-climatic factors (WMO, 2020). The location and the environment of the measurement site, the instrumentation itself as well as the observation practices may change during the measurement period. Most series are composite, which means that several station records at nearby locations are concatenated to produce the final series. Each concatenation introduces an homogeneity break in the time series. In Belgium, the progressive replacement of open shelters by Stevenson closed shelters in the early 1950s is also a source of inhomogeneities in the historical series (Delvaux et al., 2019). These non-climatic factors affecting the meteorological records reduce the reliability of the time series for assessing actual climate variations. In order to evaluate climate trends, the homogenization of the long-term climate series is therefore required. This homogenization process aims at removing the non-climatic signal in these time series.
The homogenization of the Belgian historical temperature data by the Royal Meteorological Institute of Belgium is extensively described in Delvaux et al. (2019). The monthly means of the minimum and maximum daily air temperature at 1.5 m height above ground have been homogenized using the HOMER software (Mestre et al., 2013). The results were provided for 61 series over the period 1954-2015 (long series) and for 16 series starting before 1931 (historical series) including eight covering the full time period 1880-2015. The dataset presented here is the extension of the 16 longest series to 2023.
References
Delvaux, C., Ingels, R., Vr_abe_l, V., Journ_ee, M., and Bertrand, C.: Quality control and homogenization of the Belgian historical temperature data, International Journal of Climatology, 39, 157–171, doi: https://doi.org/10.1002/joc.5792, 2019.
Mestre, O., Domonkos, P., Picard, F., Auer, I., Robin, S., Lebarbier, E., Bohm, R., Aguilar, E., Guijarro Pastor,
J. A., Vertacnik, G., et al.: HOMER: a homogenization software-methods and applications, Quarterly
Journal of the Hungarian Meteorological Service, 117, 47–67, 2013.
WMO: Guidelines on Homogenization, Tech. Rep. WMO-No. 1245., World Meteorological Organization,
Geneva, 2020.