[1] Nansen Environm & Remote Sensing Ctr, Mohn Sverdrup Ctr Global Ocean Studies & Operat O, N-5006 Bergen, Norway
[2] Univ Bergen, Inst Geophys, N-5007 Bergen, Norway
[3] Nansen Int Environm & Remote Sensing Ctr, St Petersburg 197101, Russia
[4] Bjerknes Ctr Climate Res, N-5007 Bergen, Norway
[5] Environm Syst Anal Res Ctr, Boulder, CO 80303 USA