Swiss Early Instrumental Meteorological Measurements

Abstract

Abstract. Decadal variability of weather and its extremes is still poorly understood. This is partly due to the shortness of records, which, for many parts of the world, only allow studies of 20th century weather. However, the 18th and early 19th century have seen some pronounced climatic variations, with equally pronounced impacts on the environment and society. Considerable amounts of weather data are available even for that time, but have not yet been digitised. Given the recent progress in quantitative reconstruction of sub-daily weather, such data could form the basis of weather reconstructions. In Switzerland, measurements before 1864 (the start of the national network) have never been systematically compiled except for three prominent series (Geneva, Basel, Great St. Bernard Pass). Here we provide an overview of early instrumental meteorological measurements in Switzerland resulting from an archive survey. Our inventory encompasses 335 entries from 206 locations, providing an estimated 3640 station years and reaching back to the early 18th century. Most of the data sheets have been photographed and a considerable fraction is undergoing digitisation. This paper accompanies the online publication of the imaged data series and metadata. We provide a detailed inventory of the series, discuss their historical context and provide the photographed data sheets. We demonstrate their usefulness on behalf of two historical cases and show how they complement the existing series in Europe. If similar searches in other countries yield similarly rich results, an extension of daily weather reconstructions for Europe back to the 1760s is possible.

From climate to weather reconstructions

“…The last of these is analysed in 20CRv2c [101] in Fig 6C . The figure indicates significant amounts of moisture (850 hPa specific humidity) in a frontal system stretching across Europe on 1 July 1817. Heavy precipitation is described in documentary data [102]. A weather diary from the monastery of Einsiedeln, Switzerland (Fig 6D ) indicates heavy rainfall and thunderstorms from end of June (for unknown reasons the source has a 31 June) to 5 July, the peak of the flood event.…”