In addition to its automatic precipitation measurements, MeteoSwiss also operates a manual precipitation monitoring network. Measurements are taken here once a day and transmitted to MeteoSwiss via SMS. The network comprises over 240 locations (200 stations measure rainfall and snowfall, and 40 stations measure snowfall only). Due to their long-series measurements, they are of great climatological significance. In mountainous areas that are difficult to access, around 57 totalisers are used which record the volume of precipitation for an entire year.
Manual precipitation monitoring network
As precipitation as a parameter exhibits a very high level of spatial and temporal variability, an especially dense monitoring network is required. Thus, in addition to the automatic precipitation measurements which are taken every ten minutes, precipitation readings (rainfall and snowfall) are taken on a daily basis. The stations in the manual precipitation monitoring network are of great climatological significance, as many of these measuring points have existed for many decades. The first stations of this kind were established in 1879. They are particularly valuable for long-term statistics. In the high mountains, measurements are taken using totalisers; these values are usually only recorded once a year
At these stations, the amount of precipitation is read on a daily basis. The observers record the relevant data every morning at 7:30 a.m. and send this data via SMS to MeteoSwiss, where it is immediately fed into the data warehouse. The following are measured and observed:
- Amount of precipitation during the last 24 hours in mm
- Depth of fresh snow during the last 24 hours in cm
- Total snow depth in cm
Totaliser monitoring network – annual readings
Totalisers are primarily used in mountainous areas that are difficult to access, and they record the volume of precipitation over an entire year. In the case of some totalisers, semi-annual interim measurements are taken. The amount of precipitation is measured over a 12-month period from the end of September until the end of September the following year (hydrological year). After the annual measurement has been taken, the totalisers are emptied, cleaned and re-filled with a pre-defined volume of water, calcium chloride (frost protection) and Vaseline (evaporation protection).