1. Climate Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, and School of Physics, University of Costa Rica, San José, Costa Rica
2. Climate Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California
3. Climate Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California, and Department of Civil and Environmental Engineering, University of Washington, Seattle, Washington