Satellite data increasingly contribute to the global climate observing system. Extensive international and national activities have therefore been launched to help complete the data sets of different Essential Climate Variables (ECVs).
Satellite technology has advantages compared to traditional observation methods: The ECVs can be observed around the globe, quasi continuously (geostationary satellites) or at short time intervals (polar-circumnavigating satellites). In addition, satellites supply information about remote or difficult to access areas for which no other observations are available.
The goal of international initiatives is to create global and consistent data sets of different ECVs using satellite data. The Climate Change Initiative (CCI) of the European Space Agency (ESA) or the pan-European Satellite Application Facilities (SAF) network from EUMETSAT (European Organisation for the Exploitation of Meteorological Satellites) are making an essential contribution to the global climate observing system.
The evaluation of satellite data is a challenge due to the natural conditions in Switzerland, in particular the topography. Nevertheless, the significance of the satellite-assisted observation of ECVs is rising.
Different national institutions in cooperation with international partners are active in this field:
- Since 1983, MeteoSwiss has been deriving time series of the global radiation [internal link] from data of geostationary satellites within the scope of the EUMETSAT SAF on Climate Monitoring (CM SAF).
- The Institute of Geography of the University in Bern is compiling time series of the surface temperature of select Swiss lakes, based on a long-term archive of the NOAA Advanced Very High Resolution Radiometer Sensor.
- The Institute of Geography of the University in Zurich is managing the "Glacier" portfolio of the ESA Climate Change Initiative. In support of the World Glacier Monitoring Service (WGMS), the institute is using high-resolution satellite data to create a global inventory of glaciers.
- ESA CCI "Greenhouse Gases" (GHG) is combining satellite data with model information to identify global sources and reductions in carbon dioxide and methane. The Swiss Federal Laboratories for Materials Testing and Research (Empa) are involved in the validation of the satellite data using in-situ measurements.
- Satellite-assisted derivation methods for the aerosol optical depth (AED) are analysed and compared within the scope of the ESA CCI "Aerosol". In so doing, the Paul Scherrer Institute (PSI) is playing a significant role in the validation of the satellite data with the conduct of in-situ measurements.
- The ESA CCI "Ozone" is processing global, satellite-assisted ozone data sets for climate research. The weather service MeteoSwiss is actively involved in the validation.
With the conduct of national activities, the Swiss GCOS Office is promoting the use of satellite data for the ECVs.