1. Climate Change Institute, University of Maine, Orono, Maine 04469, U.S.A.
2. Lamont-Doherty Earth Observatory, Columbia University, Palisades, New York 10964, U.S.A.
3. Department of Earth Sciences, University of Maine, Orono, Maine 04469, U.S.A.
4. Department of Computer Sciences, University of Maine, Orono, Maine 04469, U.S.A.
5. School of Science and Mathematics, University of Maine at Presque Isle, Presque Isle, Maine 04769, U.S.A.