Because stability indices that are derived from radiosoundings exhibit an insufficient temporal and spatial resolution a method was developed that delivers these information continously by using MSG-data. In a first approach the technique of Neural Network was used for the calculating the Global Instability Index (GII). The training was carried out with radiosounding measurements in Spain and radiation values of particular MSG-channels. However, first results did not fulfil the requirements for routine applications.
In the meanwhile a new technique is being used. Vertical temperature and humidity profiles from ECMWF-model are transfered With radiation transfer models to radiation amounts of the MSG-channels. The radiation values derived from the ECMWF-model are assimilated with corresponding radiation measurements of recent satellite data. This assimilated radiation fluxes of all channels are recalculated to vertical profiles of temperature and humidity. This best estimation of the vertical profiles is used for the Lifted Index.
Lifted index values from satellite data are only available in could free areas whereas model values can be calculated also in cloudy regions.
More information can be found for example in M. König, 2002. Atmospheric Instability Parameters Derived from MSG SEVIRI Observations, EUMETSAT Programme Development Department, Technical Memorandum No. 9