A Holocene record of changing Arctic Ocean ice drift analogous to the effects of the Arctic Oscillation

Abstract

[1] The Arctic Oscillation (AO) controls the configuration of the Transpolar Drift (TPD). If thicker ice from the Beaufort Gyre were exported, the volume of fresh water/sea ice in the Nordic seas would significantly increase, decreasing the formation of North Atlantic deep water. This would cool large parts of the Northern Hemisphere and affect global climate. Therefore, in order to understand how the global climate system functions, it is imperative to know how the TPD changed over the last millennium or more. The provenance of grains in a sediment core located near the confluence of the TPD and the Beaufort Gyre provides a direct proxy for changes in seaice drift owing to these circulation systems. The core has more than 200 cm of Holocene sediment, with intervals dominated by grains from the Russian shelves alternating with intervals of abundant grains from North American sources. Grains matched to Russian shelves indicate that the TPD was shifted toward North America, similar to what occurs during a more positive phase of the AO. This condition alternated with intervals where few grains matched to Russian sources, presumably because the TPD was restricted to the Russian half of the Arctic, far from the core site. During the last 1300 years, increased influx of Russian grains occurred approximately every 50-150 years. This fluctuation might represent the long-term oscillation of the AO, which modulates the same TPD shift today.

Multidecadal to millennial marine climate oscillations across the Denmark Strait (~ 66° N) over the last 2000 cal yr BP

“…2d) needs to be considered. Several recent papers have evaluated a variety of high-resolution marine proxies from off Iceland and adjacent areas and associated them with known climatic modes, such as the NAO, AO, and AMO (Jennings et al, 2002a;Darby and Bischof, 2004;Jiang et al, 2005;Knudsen et al, 2011;Miettinen et al, 2011;Darby et al, 2012;Alonso-Garcia et al, 2013;Zhang et al, 2007), although such oscillations are superimposed on both long-term insolation trends and abrupt events, such as volcanic eruptions. The underlying controls on our proxies are the variations in the landfast and drift ice and the extent and presence of Atlantic water transported via the Irminger current (Fig.…”

“…However, our estimates also include a calculation of the standard deviations of the estimate based on iterations of the 2 × 5 matrix (Andrews and Eberl, 2012); thus, we could account for nearly 100 % of the sediment composition by specific sample selection from the two source areas. Additional sediment sources would certainly be derived from icebergs that originated in Scoresby Sund and northeast Greenland and sediment entrained in sea ice from the Arctic Ocean (Andrews, 2011;Bigg, 1999;Darby and Bischof, 2004;Darby et al, 2011;Seale et al, 2011). Over the 100 yr interval ending ca.…”

Unraveling Sediment Transport Along Glaciated Margins (the Northwestern Nordic Seas) Using Quantitative X-Ray Diffraction of Bulk (< 2mm) Sediment

“…These results strongly suggest that the seaward transport of glacially derived, mafic-rich sediments from the early Tertiary volcanic outcrop overwhelms the southward transport of felsic minerals from NE Greenland and the Arctic Ocean. However, single grains in the 250-40 µm range can still be used for identification (Fe-oxide composition) of source areas around the margin of the Arctic Ocean (Darby, 2003;Darby and Bischof, 2004;Andrews et al, 2009b). Figure 9a & B shows scaled weight% values of quartz and pyroxene for surface samples from Scoresby Sund south and across to Iceland.…”

The Arctic Ocean—a Canadian perspective from IPY

“…The spatial pattern in temperature and sea ice inferred from cores suggests a link to a strongly positive Arctic Oscillation (e.g., Polyakov and Johnson 2006;Darby and Bischof 2004) during the early Holocene and later to a persistent negative phase. The same inference was made in earlier studies (Dyck et al 2010;Rimbu et al 2003).…”