Comprehensive 1000 year climatic history from an intermediate-depth ice core from the south dome of Berkner Island, Antarctica: methods, dating and first results

Abstract

A 181 m deep ice core drilled in 1994/95 on the south dome of Berkner Island, Antarctica, was analyzed for stable isotopes, major ions and microparticle concentrations. Samples for ion chromatography were prepared by using a novel technique of filling decontaminated sample from a device for continuous ice-core melting directly into the sample vials. The core was dated through identification of volcanic horizons and interpolative layer counting. The core, together with a similar core from the north dome, reveals a 1000 year history of relatively stable climate. Temporal variations in the two cores deviate from each other owing to changing patterns of regional-scale circulation; the best correspondence between them is found for MSA–. δ18O, accumulation rate and a sea-salt proxy show only negligible correlation, which suggests a complex meteorological setting. Increasing annual accumulation is observed for the last 100 years. A period of increased sea-salt concentrations started around AD 1405, as has also been observed in other cores. Microparticle concentrations are on average 1220 particles (>1.0 μm diameter) mL–1; they are enhanced from AD 1200 to 1350, possibly because of a higher atmospheric mineral dust load or because local volcanic activity was stronger than previously thought. Microparticles and NH4+ show marked but multiple and very irregular sub-annual peaks; long-term stacking of 1 year data intervals yields seasonal maxima in austral spring or mid-summer, respectively. Post-depositional redistribution was observed for MSA, NO3– and F– at volcanic horizons.

Centennial-scale variability of the Southern Hemisphere westerly wind belt in the eastern Pacific over the past two millennia

“…A factor of ∼ 3 higher dust flux (12 mg m −2 year −1 ) was reported www.clim-past.net/10/1125/2014/for the mid-to-late 19th century at James Ross Island, near the tip of the Antarctic Peninsula and close to Patagonian dust sources (McConnell et al, 2007). Similarly, although flux values have not been reported for the Berkner Island ice cores, the average dust concentration of 1220 ± 1110 particles mL −1 is 5 times that observed at WAIS Divide (230 ± 350 particles mL −1 ) for the same time period (1080( -1994, while the accumulation rate is ∼ 60 % lower (average: 130 kg m −2 year −1 vs. 207 kg m −2 year −1 at WAIS Divide; Ruth et al, 2004;Banta et al, 2008). Given the predominance of particles in the 5-10 µm diameter range at Berkner, we infer that the dust mass flux is likely greater than at WAIS Divide.…”

A synthesis of the Antarctic surface mass balance during the last 800 yr

“…However, firn cores coupled with an atmospheric reanalysis model of the AIS indicate statistically insignificant or slightly negative SMB changes in the AIS since the 1950s (Monaghan et al, 2006). SMB research based on firn/ice core records from recent decades reveals a variety of changes and trends, ranging from slight increases (Thompson et al, 1994;Morgan et al, 1991;MosleyThompson et al, 1999;Frezzotti et al, 2005;Goodwin et al, 2003;Stenni et al, 2002;Urbini et al, 2008;Igarashi et al, 2011;Fujita et al, 2011) to doublings (Thomas et al, 2008), to decreases Kaspari et al, 2004;Schlosser and Oerter, 2002;Kaczmarska et al, 2004;Ren et al, 1999), or to no significant trend in the SMB Ruth et al, 2004;Anschütz et al, 2009Anschütz et al, , 2011Sommer et al, 2000;Karlöf et al, 2005;Stenni et al, 1999).…”

115 year ice-core data from Akademii Nauk ice cap, Severnaya Zemlya: high-resolution record of Eurasian Arctic climate change

“…For the uppermost 53 m discrete samples were taken continuously under clean conditions in a resolution of 60 mm (for details of sampling see Weiler and others, 2005). For the remaining 4 m of the considered core section, we took discrete samples in a resolution of about 30 mm by using a melting device for continuous flow analysis (CFA) coupled with an autosampler system, which was also used for the analysis of the ice cores from Greenland (NorthGRIP) and Antarctica (EPICA) (for details see Ruth and others, 2004 …”