Una Miller, Lamont Doherty Earth Observatory, Palisades, NY, United States; Columbia University of New York, Earth and Environmental Sciences, New York, NY, United States, Christopher J Zappa, Columbia University, Lamont-Doherty Earth Observatory, Palisades, NY, United States, J. Thomas Farrar, Woods Hole Oceanographic Inst, Department of Physical Oceanography, Woods Hole, MA, United States, Deborah A Le Bel, Lamont -Doherty Earth Observatory, Palisades, NY, United States and Robert A Weller, WHOI, Monument Beach, MA, United States