Homogenization of daily temperature data of the five principal stations in the Netherlands (version 1.0)

Homogeneous time series of daily Tn, Tx and Tmean are indispensable for climate change and variability studies. The present study describes the homogenization of the 20th century daily mean, minimum and maximum temperatures (Tmean, Tn, Tx) of the five principal stations in the Netherlands. For the investigated stations, it is known that there have been major relocations that caused inhomogeneities. In addition, for station De Bilt the relocation was accompanied by a major change in thermometer screen. The existence of parallel data makes it possible to correct for the inhomogeneities.

The study is a logical follow-up of the recent standardization of data and methods for calculating daily Tn, Tx and Tmean for the five principal stations (Brandsma et al., 2013). The standardized series are measured series and serve as the source for calculating the homogenized series. The homogenized series presented here are not only the source for climate change and variability studies but also for calculating extremes like cold- and heat waves and their communication.

The new series are a step forward because they allow a realistic comparison of mean and extreme temperatures from the beginning of the 20th century up till now. For the stations considered, they give a consistent picture of climate change both in space and time.