1. a Geography Department , University of Maryland , College Park, Maryland, 20742, U.S.A
2. b S. T. Systems Corporation, Code 923, NASA/GSFC , Greenbelt, Maryland, 20771, U.S.A
3. c Laboratoire d'Optique Atmosphérique , Université des Sciences et Techniques de Lille , Flandres, Artois, Villeneuve d'Ascq, France
4. d Code 923, NASA/GSFC , Greenbelt, Maryland, 20771, U.S.A