The construction of a Central Netherlands temperature 1KNMI, P.O. Box 201, 3730 AE De Bilt, The Netherlands
20 May 2011
Received: 27 October 2010 – Published in Clim. Past Discuss.: 10 November 2010 Abstract. The Central Netherlands Temperature (CNT) is a monthly daily mean temperature
series constructed from homogenized time series from the centre of the
Netherlands. The purpose of this series is to offer a homogeneous time series
representative of a larger area in order to study large-scale temperature changes. It
will also facilitate a comparison with climate models, which resolve similar
Revised: 15 April 2011 – Accepted: 22 April 2011 – Published: 20 May 2011
From 1906 onwards, temperature measurements in the Netherlands have been
sufficiently standardized to construct a high-quality series. Long time
series have been constructed by merging nearby stations and using the overlap to
calibrate the differences. These long time series and a few time series of
only a few decades in length have been subjected to a homogeneity analysis
in which significant breaks and artificial trends have been corrected. Many
of the detected breaks correspond to changes in the observations that are
documented in the station metadata.
This version of the CNT, to which we attach the version number 1.1, is
constructed as the unweighted average of four stations (De Bilt,
Winterswijk/Hupsel, Oudenbosch/Gilze-Rijen and Gemert/Volkel) with the
stations Eindhoven and Deelen added from 1951 and 1958 onwards, respectively.
The global gridded datasets used for detecting and attributing climate change
are based on raw observational data. Although some homogeneity adjustments are made,
these are not based on knowledge of local circumstances but only on
statistical evidence. Despite this handicap, and the fact that these datasets use grid
boxes that are far larger then the area associated with that of the Central
Netherlands Temperature, the temperature interpolated to the CNT region shows
a warming trend that is broadly consistent with the CNT trend in all of these
datasets. The actual trends differ from the CNT trend up to 30 %, which
highlights the need to base future global gridded temperature datasets on
homogenized time series.
Citation: van der Schrier, G., van Ulden, A., and van Oldenborgh, G. J.: The construction of a Central Netherlands temperature, Clim. Past, 7, 527-542, doi:10.5194/cp-7-527-2011, 2011.