Rain gauge European collection developed under the project currently consists of more than 8000 stations belonging to climatological, synoptic and special precipitation networks. The four major sources of information collected at climatological and synoptic stations are presented in Figure 1.
Figure 1. Spatial distribution of European rain gauge stations. European stations consist of KNMI collection (red dots), NCDC collection (black dots), DWD collection (green dots) and Russian and Ukrainian meteorological services collections (yellow dots).
The data collections include daily precipitation from the Royal Netherlands Meteorological Institute (KNMI) data set, known as European Climate Assessment (ECA) daily dataset (Klein Tank et al. 2002), which consists of 201 stations digitized directly from the log-books. These data were merged with the regional German Weather Service (DWD) collection of about 46 stations with the observations of the same quality. Additionally we used 888 stations obtained from the U.S. National Climatic Data Center (NCDC) collection. However, these data were retrieved from the SYNOP code and still contain some uncertainties associated with the changes in observational times and the convergence from millimetres to inches and back. Finally the Russian and Ukrainian collections consist of 850 and 229 stations respectively, most of which were directly digitized from the log-books. The merged data set consists of about 1998 stations, approximately 65% of which provide measurements for periods from 50 to 100 years and 20% for more than 100 years starting from the mid 19th century onwards. The data set has a quite inhomogeneous spatial coverage with the highest station density in Central Europe and a noticeable drop of the number of observational sites in the Southern and Northern Europe. However, the sheer number of stations should allow for homogenisation of coverage through decimation.
Precipitation data from the high resolution rain gauge synoptic network of German Weather service (DWD) were collected ny MIUB in co-operation with the end-user (DWD) and IORAS. The collected 5444 stations consist of special precipitation network along with the German synoptic stations. They provide very dense coverage of Germany proper with most typical spatial resolution of about 1-3 kilometres. These data cover the period from 1930 onwards with more gaps in the data records in the pre-WWII period. The data set was digitized and controlled for quality.