Temperature difference across the Lomonosov Ridge: Implications for the Atlantic water circulation in the Arctic Ocean

Drifting buoy observations in the Arctic Ocean indicate that, unlike climatological conditions, the temperature of the upper Atlantic water was higher in the Makarov Basin side of the Lomonosov Ridge than in the Amundsen Basin side in 2004. Hydrographic data from 1991 to 2004 has been compared with climatology to examine the relative phase of Atlantic water temperature change in these regions. On the Amundsen Basin side of the Lomonosov Ridge, a positive temperature anomaly in the Atlantic water began in the early 1990s, continued from the mid-1990s to the early 2000s and started decreasing in 2004. In contrast, positive temperature anomalies were first apparent on the Makarov Basin side of the Lomonosov Ridge in 2000, and continue in 2004. Recent historical data indicates that the arrival of temperature anomalies on the Makarov Basin side of the Lomonosov Ridge is delayed about 7 years after arrival on the Amundsen Basin side. Our results support the idea that Atlantic Water circulates cyclonically around the periphery of the Makarov basin at a propagation speed of 1-2 cm s(-1).