[1] Univ Maryland, College Pk, MD 20742 USA
[2] NASA, Jet Prop Lab, Washington, DC USA
[3] Columbia Univ, Lamont Doherty Earth Observ, New York, NY 10027 USA
[4] Univ Washington, Seattle, WA 98195 USA
[5] Woods Hole Oceanog Inst, Woods Hole, MA 02543 USA