Observed changes in Arctic Ocean temperature structure over the past half decade

Ocean temperature data obtained from the central Arctic Ocean during 1995-1 999 show interannual changes in the temperature of the warm Atlantic Water core. Widespread warming continued from 1995 until 1998 but had ceased duri ng 1998-1999 and was replaced by a slight cooling. The timing of these chan ges differed regionally, as the warming had occurred prior to 1995 in the N ansen and Amundsen basins, and between 1995 to 1998 in the Makarov Basin. T he regional phase differences are consistent with advection along mid-ocean ridges from the Eurasian margin slope current, which provides the source f or warm Atlantic Water. Anomalous behaviors were associated with the Arctic Mid-Ocean and Lomonosov ridges and probably reflected the presence of over lying topographically trapped circulations.