1. a Faculty of Electronics and Computer Science Laboratory of Image Processing and Radiation , University of Sciences and Technology of Algiers (U.S.T.H.B.) , PO Box 32 El Alia, Bab Ezzouar, Algiers, Algeria
2. b Observatoire Midi-Pyrénées, Laboratoire d'Aérologie , Université Paul Sabatier , 14 avenue Edouard Belin, Toulouse, 31400, France E-mail:
3. c Office National de la M@téorologie , Bd Mohamed Khemisti, Dar El Beida, Alger, Algérie