Hydrography of the upper Arctic Ocean measured from the nuclear submarine U.S.S. Pargo

In 1993, the USS Pargo made the first civilian oceanographic submarine cruise in the Arctic Ocean. The hydrographic measurements provide a unique synoptic description of the upper Arctic Ocean. The results indicate that the influence of Atlantic Water has increased relative to existing climatologies. The front between waters with an Atlantic versus Pacific character has shifted from over the Lomonosov Ridge to roughly over the Alpha and Mendeleyev Ridges. Warm cores of Atlantic Water are observed over the Lomonosov and Mendeleyev Ridges. These data indicate a fundamental change in the circulation of the Arctic Ocean beginning in the early 1990s.