1. Department of Earth and Atmospheric Sciences, City College of New York, New York, New York
2. Wegener Center for Climate and Global Change, and Institute for Geophysics, Astrophysics and Meteorology/Institute of Physics, University of Graz, Graz, Austria, and Lamont–Doherty Earth Observatory, Columbia University, New York, New York
3. Lamont–Doherty Earth Observatory, Columbia University, New York, New York