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

Abstract

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.

Toward a warmer Arctic Ocean: Spreading of the early 21st century Atlantic Water warm anomaly along the Eurasian Basin margins

“…Our estimation shows this spatial feature is not attributable to the AW jet migration across the Eurasian flank of the Lomonosov Ridge because the magnitude of δ here is much smaller than the magnitude of the anomaly. The low magnitude of δ near the North Pole is also confirmed by aerial hydrographic CTD surveys from 2002 to 2006 [see, e.g., Kikuchi at al. , 2005].…”

Observations of water masses and circulation with focus on the Eurasian Basin of the Arctic Ocean from the 1990s to the late 2000s

“…This suggests that the warm Atlantic water entering the Makarov Basin in the 1990s (Carmack et al, 1995) now had circulated around the basin and was moving along the Lomonosov Ridge towards Siberia. A similar interpretation was made earlier by Kikuchi et al (2005). In the Amundsen Basin and over the Lomonosov Ridge, the lower tempera- Rudels et al, 1994.…”

“…The temperature of the Atlantic water on the Makarov Basin side of the Lomonosov Ridge had increased by 2004 (Kikuchi et al, 2005), and the observations from Oden 2005 indicated that the temperatures at the Makarov Basin side were as high, or even higher than, on the Amundsen Basin side (see Figs. 1 and 13).…”

Relaxation of central Arctic Ocean hydrography to pre‐1990s climatology

“…Lags in water properties occur in part because, even if circulation remained constant, the transit times required to move a changed water property through the basin are measured in years [Polyakov et al, 2005]. For example, a 7-year lag between Atlantic water temperature rise in the Makarov Basin and that initially seen at the North Pole was found by Kikuchi et al [2005]. More importantly, the time for the ocean circulation to adjust baroclinically to a change in wind forcing is long.…”