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Dust-climate couplings over the past 800,000 years from the EPICA Dome C ice core

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  • Earth Science
  • Geography

Abstract

untitled LETTERS Dust2climate couplings over the past 800,000 years from the EPICA Dome C ice core F. Lambert1,2, B. Delmonte3, J. R. Petit4, M. Bigler1,5, P. R. Kaufmann1,2, M. A. Hutterli6, T. F. Stocker1,2, U. Ruth7, J. P. Steffensen5 & V. Maggi3 Dust can affect the radiative balance of the atmosphere by absorb- ing or reflecting incoming solar radiation1; it can also be a source of micronutrients, such as iron, to the ocean2. It has been sug- gested that production, transport and deposition of dust is influ- enced by climatic changes on glacial2interglacial timescales3–6. Here we present a high-resolution record of aeolian dust from the EPICA Dome C ice core in East Antarctica, which provides an undisturbed climate sequence over the past eight climatic cycles7,8. We find that there is a significant correlation between dust flux and temperature records during glacial periods that is absent during interglacial periods. Our data suggest that dust flux is increasingly correlated with Antarctic temperature as the cli- mate becomes colder. We interpret this as progressive coupling of the climates of Antarctic and lower latitudes. Limited changes in glacial2interglacial atmospheric transport time4,9,10 suggest that the sources and lifetime of dust are the main factors controlling the high glacial dust input.We propose that the observed 25-fold increase in glacial dust flux over all eight glacial periods can be attributed to a strengthening of South American dust sources, together with a longer lifetime for atmospheric dust particles in the upper troposphere resulting from a reduced hydrological cycle during the ice ages. The EPICA (European Project for Ice Coring in Antarctica) ice core drilled at Dome C (hereafter EDC) in East Antarctica (75u 069 S; 123u 219 E) covers the past 800,000 yr (Fig. 1a). The dust flux record of Vostok (Fig. 1b) is thus extended over four additional cycles (Fig. 1c). The glacial–interglacial climate changes are well reflected in the sequence of high and low dust c

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