Correction of rainfall series in the Netherlands resulting from leaky rain gauges

In the period 2012-2014 new rain gauges were installed on the 320 stations of the KNMI manual daily rainfall network. In the beginning of 2017 it turned out that part of the gauges were probably leaky as a result of a design fault. As the rainfall of this network serves as the reference rainfall for the Netherlands, immediate action was needed.

Within two months all stations were inspected. During the inspections the (potential) leakiness of the rain gauge at each station was determined. All rain gauges were sealed on site to prevent further leakage. Part of the rain gauges were examined at KNMI in De Bilt and a field experiment was set up to study the problem in more detail. In addition, a project was started to correct the rainfall series of stations with potentially leaky gauges.

This report describes the work needed for the correction of the daily rainfall series of stations with leaky rain gauges.