Le pluviographe centenaire du plateau d'Uccle: son histoire, ses données et ses applications

The Hellmann-Fuess recording raingauge at the Plateau of Uccle, the site in the south of Brussels where are located the Royal Observatory of Belgium (ORB) and the Royal Meteorological Institute of Belgium (IRM), is more than one hundred years old. Indeed, it was in May 1898, that an instrument of that type was installed on these grounds. Since more than a century such instruments have been functioning at this location without appreciable interruption. This means that these observations constitute one of the longest high frequency (every 10 minutes) time-series of precipitation in the world. The present paper draws the history of the recording raingauges in use at the above-mentioned scientific institutions. However, the Hellmann-Fuess recording raingauge was preceded by, at least, three other types of instruments. At first, a "meteographe universel", invented by F. Van Rijsselberghe, was put in function in 1879. It was followed, in January 1893, by a recording raingauge constructed by H.J. Walravens of the Royal Observatory of Belgium. Finally, in September 1896, a Swiss Hottinger recording raingauge was installed. This latter one continued to function in parallel with the Hellmann-Fuess recording raingauge until the twenties. What makes the history of the Hellmann-Fuess recording raingauge so interesting, is the fact that nearly all charts had been stored in the archives of the IRM. Recently, a project funded partially by the Ministry of the Flemish Community, has led to files in computer readable form (CRF) of the information. The data set comprising now more than five and a half million of precipitation data with a time step of 10 minutes constitutes a unique set of information on the precipitation climate at Uccle over more than one hundred years.