Trajectory shifts in the Arctic and Subarctic freshwater cycle

Author Posting. © The Author(s), 2006. This is the author's version of the work. It is posted here by permission of American Association for the Advancement of Science for personal use, not for redistribution. The definitive version was published in Science 313 (2006): 1061-1066, doi:10.1126/science.1122593.Manifold changes in the freshwater cycle of high-latitude lands and oceans have been reported in the past few years. A synthesis of these changes in sources of freshwater and in ocean freshwater storage illustrates the complementary and synoptic temporal pattern and magnitude of these changes over the past 50 years. Increasing river discharge anomalies and excess net precipitation on the ocean contributed ~20,000 km3 of fresh water to the Arctic and high latitude North Atlantic oceans from lows in the 1960s to highs in the 1990s. Sea ice attrition provided another ~15,000 km3, and glacial melt added ~2000 km3. The sum of anomalous inputs from these freshwater sources matched the amount and rate at which fresh water accumulated in the North Atlantic during much of the period from 1965 through 1995. The changes in freshwater inputs and ocean storage occurred in conjunction with the amplifying North Atlantic Oscillation and rising air temperatures. Fresh water may now be accumulating in the Arctic Ocean and will likely be exported southward if and when the North Atlantic Oscillation enters into a new high phase.Funding was provided by NSF (grants OPP-0229302, OPP- 0436118, OPP-0327664, OPP-0352754, OPP-0519840, OCE- 0326778), ONR (grant N00014-02-1-0305) and NASA (grant IDS-03-0000-0145)