[1] NASA, LANGLEY RES CTR, DIV ATMOSPHER SCI, HAMPTON, VA 23681 USA
[2] CALTECH, JET PROP LAB, PASADENA, CA 91109 USA
[3] UNIV EDINBURGH, DEPT METEOROL, EDINBURGH EH9 3JZ, MIDLOTHIAN, SCOTLAND
[4] HERIOT WATT UNIV, DEPT PHYS, EDINBURGH EH14 4AS, MIDLOTHIAN, SCOTLAND