Centennial mineral dust variability in high-resolution ice core data from Dome C, Antarctica

Abstract

Abstract. Ice core data from Antarctica provide detailed insights into the characteristics of past climate, atmospheric circulation, as well as changes in the aerosol load of the atmosphere. We present high-resolution records of soluble calcium (Ca 2+ ), non-sea-salt soluble calcium (nssCa 2+ ), and particulate mineral dust aerosol from the East Antarctic Plateau at a depth resolution of 1 cm, spanning the past 800 000 years. Despite the fact that all three parameters are largely dust-derived, the ratio of nssCa 2+ to particulate dust is dependent on the particulate dust concentration itself. We used principal component analysis to extract the joint climatic signal and produce a common high-resolution record of dust flux. This new record is used to identify Antarctic warming events during the past eight glacial periods. The phasing of dust flux and CO 2 changes during glacialinterglacial transitions reveals that iron fertilization of the Southern Ocean during the past nine glacial terminations was not the dominant factor in the deglacial rise of CO 2 concentrations. Rapid changes in dust flux during glacial terminations and Antarctic warming events point to a rapid response of the southern westerly wind belt in the region of southern South American dust sources on changing climate conditions. The clear lead of these dust changes on temperature rise suggests that an atmospheric reorganization occurred in the Southern Hemisphere before the Southern Ocean warmed significantly.

A reconstruction of atmospheric carbon dioxide and its stable carbon isotopic composition from the penultimate glacial maximum to the last glacial inception

“…Applying an age scale compression of the TALDICE-1 dating (process i) between 129 000 and 126 000 yr BP, the broad shape of the early CO 2 peak from the Talos Dome matches the timing of the peak reconstructed from the EDC ice core, but can not explain the higher CO 2 concentrations. In situ production of CO 2 (process ii) in the Talos Dome ice core is unlikely to Jouzel et al, 2007), the δ 13 C atm MCA (red line, Schmitt et al, 2012) as well as a SST-corrected version (black line) according to a global SST reconstruction, which is based on the sea-ice-free surface ocean only (light blue line) , CaCO 3 weight percent content of sediment cores ODP1089 (red upward pointing triangles) and ODP1090 (magenta downward pointing triangles) (Hodell et al, 2001) as well as the dust flux reconstructed from the EDC ice core (grey line) (Lambert et al, 2012) for the last 24 000 yr. Ice core data are given on the EDC3/TALDICE-1a age scale, while marine CaCO 3 reconstructions are given on their individual age scales. In the lower panels, the same species are plotted for the time between 155 000-105 000 yr BP.…”

“…However, we can say that the major increase in CO 2 (and δD) starts at 136 000 yr BP, while the first strong decrease in aeolian dust deposition (Fig. 2) occurs already at 138 000 yr BP (Lambert et al, 2012). Also it becomes clear that the overall magnitudes of the δ 13 C atm decline at the start of Termination I and II are slightly different: after the LGM δ 13 C atm drops by about 0.3 ‰, whereas along Termination II a maximum decline of 0.2 ‰ is found.…”

Deciphering human–climate interactions in an ombrotrophic peat record: REE, Nd and Pb isotope signatures of dust supplies over the last 2500years (Misten bog, Belgium)

“…Our knowledge of climate evolution is derived from the analysis of biological and geological archives, such as tree rings (e.g., Lieubeau et al, 2007), ice cores (e.g., Lambert et al, 2012), marine and lacustrine sediments (e.g., Bradley, 1999). Peatlands (i.e., soils accumulating partially decomposed plant remains with above 50% of organic matter and greater than 30 cm deep, Clymo, 1987) are continental archives of particular interest because they are easy to date, have a high temporal resolution (decadal) and contain multiple measurable parameters dependent on environmental conditions including temperature and/or humidity, atmospheric circulation and wind strength (e.g., Chambers et al, 2012).…”

Particle shape accounts for instrumental discrepancy in ice core dust size distributions

“…The volume mode of the glacial dust is 2 µm, while it is 20 µm for the Holocene dust, due to the increased transport induced size fractionation for the glacial dust (Ruth et al, 2003). Although both instruments are typically calibrated using standard spheres of known diameter, they produce substantially different size distribution results when ice core samples are measured (Ruth et al, 2003;Lambert et al, 2008Lambert et al, , 2012Koffman et al, 2014). It has been proposed that this difference is because ice core dust is generally non-spherical (Lambert et al, 2012;Potenza et al, 2016).…”

“…The Abakus on a CFA system can have a measurement depth resolution of 3 mm (Bigler et al, 2011), and requires almost no maintenance when the CFA system is running. The Coulter Counter on the other hand typically integrates a thicker interval, and requires work from the operator all the time during measurements (Delmonte et al, 2004;Lambert et al, 2012). 15 The aspect ratio of ice core dust particles was measured using the novel Single Particle Extinction and Scattering (SPES) instrument Potenza et al, 2016).…”