1. Università Degli Studi di Roma La Sapienza,Department of Information Engineering (DIET),Rome,Italy,00184
2. European Organization for the Exploitation of Meteorological Satellites (EUMETSAT),Remote Sensing and Product Division,Darmstadt,Germany,64295
3. Institute of Atmospheric Sciences and Climate (CNR-ISAC),National Research Council of Italy,Rome,Italy,00133
4. Swedish Meteorological and Hydrological Institute (SMHI),Gothenburg,Sweden