Abstract
Abstract. In this study we report on new non-sea salt calcium (nssCa2+, mineral dust proxy) and sea salt sodium (ssNa+, sea ice proxy) records along the East Antarctic Talos Dome deep ice core in centennial resolution reaching back 150 thousand years (ka) before present. During glacial conditions nssCa2+ fluxes in Talos Dome are strongly related to temperature as has been observed before in other deep Antarctic ice core records, and has been associated with synchronous changes in the main source region (southern South America) during climate variations in the last glacial. However, during warmer climate conditions Talos Dome mineral dust input is clearly elevated compared to other records mainly due to the contribution of additional local dust sources in the Ross Sea area. Based on a simple transport model, we compare nssCa2+ fluxes of different East Antarctic ice cores. From this multi-site comparison we conclude that changes in transport efficiency or atmospheric lifetime of dust particles do have a minor effect compared to source strength changes on the large-scale concentration changes observed in Antarctic ice cores during climate variations of the past 150 ka. Our transport model applied on ice core data is further validated by climate model data. The availability of multiple East Antarctic nssCa2+ records also allows for a revision of a former estimate on the atmospheric CO2 sensitivity to reduced dust induced iron fertilisation in the Southern Ocean during the transition from the Last Glacial Maximum to the Holocene (T1). While a former estimate based on the EPICA Dome C (EDC) record only suggested 20 ppm, we find that reduced dust induced iron fertilisation in the Southern Ocean may be responsible for up to 40 ppm of the total atmospheric CO2 increase during T1. During the last interglacial, ssNa+ levels of EDC and EPICA Dronning Maud Land (EDML) are only half of the Holocene levels, in line with higher temperatures during that period, indicating much reduced sea ice extent in the Atlantic as well as the Indian Ocean sector of the Southern Ocean. In contrast, Holocene ssNa+ flux in Talos Dome is about the same as during the last interglacial, indicating that there was similar ice cover present in the Ross Sea area during MIS 5.5 as during the Holocene.
Highlights
Long and detailed climate records obtained from deep ice cores drilled on the East Antarctic ice sheet allow one to assess the past climate variability on various timescales at high southern latitudes (e.g. Petit et al, 1999; European Project for Ice Coring in Antarctica (EPICA), 2004; Brook et al, 2005; EPICA, 2006; Jouzel et al, 2007)
While a former estimate based on the EPICA Dome C (EDC) record only suggested 20 ppm, we find that reduced dust induced iron fertilisation in the Southern Ocean may be responsible for up to 40 ppm of the total atmospheric CO2 increase during T1
In this study we report on mineral dust represented by non-sea salt calcium and sea salt aerosol represented by sea salt sodium records from Talos Dome Ice core Project (TALDICE) in centennial resolution reaching back 150 thousand years before present, where present refers to 1950 AD
Summary
Long and detailed climate records obtained from deep ice cores drilled on the East Antarctic ice sheet allow one to assess the past climate variability on various timescales at high southern latitudes (e.g. Petit et al, 1999; EPICA, 2004; Brook et al, 2005; EPICA, 2006; Jouzel et al, 2007). One possibility to assess past changes in these two parameters are proxy-aerosol records in deep Antarctic ice cores, which provide detailed information on mineral dust deposition and sea ice coverage in different regions of Antarctica (Petit et al, 1990; Röthlisberger et al, 2002; Wolff et al, 2003, 2006; Fischer et al, 2007b; Bigler et al, 2010; Abram et al, 2013)
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