North Atlantic Deep Water North Atlantic Deep Water formation has been dramatically reduced at times during the past (such as during the Younger Dryas or during Heinrich events), and that this might correlate with a decrease in the strength of the Gulf Stream and the North Atlantic drift, in turn cooling the climate of northwestern Europe. There is concern that global warming might cause this to happen again. It is also hypothesized that during the Last Glacial Maximum (LGM), NADW was replaced with an analogous watermass that occupied a shallower depth known as Glacial North Atlantic Intermediate Water (GNAIW). North Atlantic Deep Water North
Transpolar Drift Stream toward the Beaufort Sea before exiting to the Atlantic Ocean. It has been cited as a major factor in the North Atlantic Oscillation and Arctic oscillation atmospheric changes. The drift typically takes one of two paths before exiting into the northern Atlantic Ocean. On decadal and longer timescales, the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO) indices affect the flow pattern of the transpolar drift stream. During times of positive NAO (NAO+) and positive AO (AO+), there is a weak Arctic high and the associated surface winds produce a cyclonic (anti-clockwise) ice drift motion in eastern Arctic Ocean.