[1] UNIV HAWAII, HAWAII INST GEOPHYS, HONOLULU, HI 96822 USA
[2] FISHERIES & OCEANS CANADA INST OCEAN SCI, SIDNEY V8L 4B2, BC, CANADA
[3] PRINCETON UNIV, PLASMA PHYS LAB, PRINCETON, NJ 08544 USA
[4] LA JOLLA INST, CTR STUDIES NONLINEAR DYNAM, LA JOLLA, CA 92038 USA