[1] Cornell Univ, Dept Earth & Atmospher Sci, Ithaca, NY 14850 USA
[2] Univ Minnesota, Dept Geog, Minneapolis, MN 55455 USA
[3] Columbia Univ, Lamont Doherty Earth Observ, Div Ocean & Climate Phys, Palisades, NY USA
[4] Natl Ctr Atmospher Res, Climate & Large Scale Dynam Lab, POB 3000, Boulder, CO 80307 USA
[5] NASA, Goddard Inst Space Studies, New York, NY 10025 USA
[6] Dartmouth Coll, Dept Geog, Hanover, NH 03755 USA
[7] Univ Calif Santa Barbara, Bren Sch Environm Sci & Management, Santa Barbara, CA 93106 USA