ARCTIC OCEAN VARIABILITY:

WHAT DO RUSSIAN MEASUREMENTS TELL US?

Knut Aagaard (UW), James Swift (UCSD), Leonid Timokhov (Arctic and Antarctic
Research Institute, St. Petersburg)

Corresponding author: Knut Aagaard (aagaard@apl.washington.edu)

OVERVIEW

We are investigating interannual to decadal variability of temperature and other water properties in Arctic Ocean waters via an enhanced version of the 1948-1993 data released under the Gore-Chernomyrdin environmental bilateral agreement. We find an elevated 1.5 °C core temperature in the eastern Amundsen Basin in 1993 in the Russian data that may be part of the Arctic warming signal discussed in the recent literature. A similar signal appears to have propagated into the Arctic Ocean beginning about 1960, with warming persisting in the Amundsen Basin for perhaps nine years. Fluctuations in Atlantic layer temperature that persist for more than a year are seen in all of the Eurasian Basin sub-regions, but the very warm Atlantic waters often found in the southwestern Nansen Basin are significantly cooled before propagating farther into the Arctic Ocean, and seaward of the Kara and Laptev seas the layer just under the Atlantic core shows signs of dense cooled water entering from the Siberian shelf seas.

Atlantic layer core temperatures in the central Makarov Basin are little different from those nearer the supposed entry region in the southern Makarov Basin, possibly indicating either a more direct source to the central basin from over the Lomonosov Ridge, or a vigorous internal circulation in the Makarov Basin. The data show no Atlantic layer warm events in the Makarov Basin before 1991 that are as strong as the widely-reported event observed during the 1990s. We find a moderate correlation between the Chukchi borderland record and that from the southern Makarov Basin, indicating that some temperature fluctuations propagate through this region, and indeed we see evidence of the 1960s warm event reaching this area. Finally, there is evidence that some of the Atlantic layer temperature fluctuations in the Chukchi borderland propagate directly into the northern Canada Basin, leaving the southern Canada Basin and the region between the Alpha and Lomonosov ridges as the most isolated part of the Arctic Ocean.

We gratefully acknowledge financial support for this work from the National Science Foundation (NSF).

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