GNSS based determination of atmospheric humidity changes and their assimilation into operational weather forecast systems (GNSSMET Austria)

  2009-04-01 - 2011-03-31

The microwave signals of the GNSS satellites (GPS, GLONASS and in future GALILEO) are time delayed when passing the atmosphere. Based on this signal delay, e.g. the humidity distribution within the troposphere can be determined. This proposal is based on the results of the already finished project GNSSMET. The main task within GNSSMET was to investigate if and how the atmospheric precipitable water content (derived from GPS data) can be used within an operational Nowcasting system (INCA). It has been proved that e.g. passing weather fronts can be analysed much better by introduced GNSS derived tropospheric wet delays because this data is influenced by changes in humidity in the free atmosphere, whereas the data at the meteorological ground stations reacts to these changes only with a time delay. This allows to forecast heavy rainfall causing potentially local floodings more reliable and to narrow down the affected region. The basic strategy of immediate use of GPS data without appropriate weighting within the INCA system was not successful due to the influence of the atmospheric ground layer. By means of the GPS data it could be shown that the INCA system is vertically over-extrapolating the humidity content observed at the meteo-stations. The goal of this proposed project is to provide the integral humidity values (estimated by GPS and GLONASS data) for the whole Austrian territory with a spatial resolution of about 50 km and a temporal resolution of 1 hour. These values shall be assimilated into ALADIN and analysed regarding their influence on the forecast model. Additionally, some innovative approaches in data modelling (Global Mapping Function, PPP, tomography) will be tested.

Project manager Project members
  •   Gregor Möller
  •   Ana Karabatic
  •   Österreichische Forschungsförderungsgesellschaft mbH (FFG)
  •   Zentralanstalt für Meteorologie und Geodynamik
  •   Burgenländische Elektrizitäts AG
  •   Wienstrom GmbH
  •   ÖBB Infrastruktur Bau AG