As part of the federal government’s Energy Strategy 2050, the interactive application sonnendach.ch, a joint project between the Swiss Federal Office of Energy, the Federal Office of Topography Swisstopo and MeteoSwiss, was created for all properties in Switzerland. The website provides an analysis of the solar potential of all buildings in Switzerland based on solar radiation data from satellites. With just a few clicks of the mouse, every person in Switzerland can estimate whether the roof or façade of their building is suitable for producing solar electricity and solar heat.
Surface temperature and drought
Satellites measure the temperature of the outermost layer of the Earth. MeteoSwiss has developed special algorithms that can ascertain, with an accuracy of about one degree, the surface temperature from Meteosat satellite measurements dating all the way back to the 1990s. When surface temperature data are combined with vegetation data, the climatological vegetation health index (VHI) can be calculated.
This makes it possible to forecast whether and how drought will develop, which is important for agriculture, forestry and energy management. Since vegetation data are not available from old Meteosat measurements, MeteoSwiss combines Meteosat surface temperature data with satellite-based vegetation data from the United States National Oceanic and Atmospheric Administration (NOAA).
The VHI drought index shows how hot the Earth’s surface was and how brown the vegetation of Switzerland was compared to the normal period of 1991–2020. These data can be used to visualise drought in Switzerland since 1991. Dry soil is significantly warmer than wet soil, and the vegetation considerably browner. 2003, 2015 and 2018 were significantly drier compared to the normal period of 1991–2020. 2003 was the first year since 1991 in which the whole of Switzerland was affected by drought. In 2015 and 2018, the Swiss plateau in particular was very dry.