Holocene Climate Variability in Antarctica Based on 11 Ice-Core Isotopic Records

Masson, Valérie; Vimeux, Françoise; Jouzel, Jean; Morgan, Vin; Delmotte, Marc; Ciais, Philippe; Hammer, C. U.; Johnsen, S. J.; Lipenkov, V. Ya.; Mosley‐Thompson, Ellen; Petit, Jean‐Robert; Steig, Eric J.; Stiévenard, M.; Vaikmäe, Rein

doi:10.1006/qres.2000.2172

Cited by 315 publications

(248 citation statements)

References 44 publications

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“…4). For the early Holocene, such a mechanism has been invoked for explaining warm temperatures in the Southern Ocean and Antarctica 18 and is consistent with a reconstruction of the AMOC strength in the North Atlantic 19 (Fig. 3b).…”

supporting

confidence: 82%

Holocene changes in the position and intensity of the southern westerly wind belt

Lamy¹,

Kilian²,

Arz³

et al. 2010

Nature Geosci

363

356

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The position and intensity of the southern westerly wind belt varies seasonally as a consequence of changes in sea surface temperature. During the austral winter, the belt expands northward and the wind intensity in the core decreases. Conversely, during the summer, the belt contracts, and the intensity within the core is strengthened. Reconstructions of the westerly winds since the last glacial maximum, however, have suggested that changes at a single site reflected shifts throughout the entire southern wind belt 1-4 . Here we use sedimentological and pollen records to reconstruct precipitation patterns over the past 12,500 yr from sites along the windward side of the Andes. Precipitation at the sites, located in the present core and northern margin of the westerlies, is driven almost entirely by the wind belt 5 , and can be used to reconstruct its intensity. Rather than varying coherently throughout the Holocene epoch, we find a distinct anti-phasing of wind strength between the core and northern margin over multi-millennial timescales. During the early Holocene, the core westerlies were strong whereas the northern margin westerlies were weak. We observe the opposite pattern in the late Holocene. As this variation resembles modern seasonal variability, we suggest that our observed changes in westerly wind strength can best be explained by variations in sea surface temperature in the eastern South Pacific Ocean.Chile is ideally located to reconstruct past variability of the southern westerly wind belt (SWW) as the SWW almost entirely controls precipitation on the western side of the Andes in southern South America with an extreme north-south rainfall gradient from the semiarid, winter-rain climate in central Chile to yearround hyper-humid conditions in the fjord region of southern Chile 5 (Supplementary Fig. S1). Therefore, any paleoclimatic proxy record primarily controlled by rainfall changes is suitable for reconstructing past changes in the SWW in this region. In present-day austral winters, the SWW extends northward, providing rainfall to central Chile (33 • -40 • S), but zonal winds are reduced in its core zone in southernmost Chile (50 • -55 • S; Fig. 1a). During austral summer, the zonal wind pattern shows a latitudinally more confined and intensified SWW with maxima over southernmost Chile (Fig. 1b). Previous reconstructions of the SWW were primarily based on single sites and generally suggested a northward migration and intensification of the SWW during colder periods 1,2,4 . Intensity variations across the wind belt have only recently been addressed and interpreted in terms of co-varying

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supporting

confidence: 82%

Holocene changes in the position and intensity of the southern westerly wind belt

Lamy¹,

Kilian²,

Arz³

et al. 2010

Nature Geosci

363

356

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“…Hillenbrand and others, 2012) and where ice-core records show a widespread warming over the entire continent (Masson and others, 2000). It is well known that the accumulation pattern in Antarctica is controlled by distance from the coast, which is strongly correlated with surface elevation.…”

Section: Discussionmentioning

confidence: 99%

Constraining past accumulation in the central Pine Island Glacier basin, West Antarctica, using radio-echo sounding

et al. 2014

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ABSTRACT. The potential for future dynamical instability of Pine Island Glacier, West Antarctica, has been addressed in a number of studies, but information on its past remains limited. In this study we use airborne radio-echo sounding (RES) data acquired over Pine Island Glacier to investigate past variations in accumulation pattern. In the dataset a distinctive pattern of layers was identified in the central part of the glacier basin. We use these layers as chronological identifiers in order to construct elevation maps of the internal stratigraphy. The observed internal layer stratigraphy is then compared to calculated stratigraphy from a three-dimensional ice-flow model that has been forced with different accumulation scenarios. The model results indicate that the accumulation pattern is likely to have changed at least twice since the deposition of the deepest identified layer. Additional RES data linked to the Byrd ice core provide an approximate timescale. This timescale suggests that the layers were deposited at the beginning of or during the Holocene period. Thus the widespread changes occurring in the coastal extent of the West Antarctic ice sheet at the end of the last glacial period could have been accompanied by changes in accumulation pattern.

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“…yrs BP (Mayr et al, 2007). Temperature reconstructions from Antarctic ice cores show that the Holocene thermal optimum came to an end at about this time (Epica Community Members, 2004;Masson et al, 2000) (Fig. 3), which resulted in expanded sea ice and a steeper meridional temperature gradient in the Southern Ocean.…”

Section: Discussionmentioning

confidence: 99%

South Atlantic island record reveals a South Atlantic response to the 8.2 kyr event

et al. 2008

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Abstract.One of the most distinct climate fluctuations during the Holocene is the short and rapid event centred around 8200 years ago, the 8.2 kyr event, which was most likely triggered by glacial melt-water forcing from the receding Laurentide ice-sheet. Evidence for this cooling has primarily been reported from sites around the North Atlantic, but an increasing number of observations imply a more widespread occurrence. Palaeoclimate archives from the Southern Hemisphere have hitherto failed to uncover a distinct climatic anomaly associated with the 8.2 kyr event. Here we present a lake sediment record from Nightingale Island in the central South Atlantic showing enhanced precipitation between 8275 and 8025 cal. yrs BP, most likely as a consequence of increased sea surface temperature (SST). We show that this is consistent with climate model projections of a warming of the South Atlantic in response to reduced north-ward energy transport during the 8.2 kyr event.

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Holocene Climate Variability in Antarctica Based on 11 Ice-Core Isotopic Records

Cited by 315 publications

References 44 publications

Holocene changes in the position and intensity of the southern westerly wind belt

Holocene changes in the position and intensity of the southern westerly wind belt

Constraining past accumulation in the central Pine Island Glacier basin, West Antarctica, using radio-echo sounding

South Atlantic island record reveals a South Atlantic response to the 8.2 kyr event

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