Eight centuries of volcanic signal and climate change at Talos Dome (East Antarctica)

Abstract

[1] During the 1996 Programma Nazionale di Ricerche in Antartide-International Trans-Antarctic Scientific Expedition traverse, two firn cores were retrieved from the Talos Dome area (East Antarctica) at elevations of 2316 m (TD, 89 m long) and 2246 m (ST556, 19 m long). Cores were dated by using seasonal variations in non-sea-salt (nss) SO 4 2À concentrations coupled with the recognition of tritium marker level (1965 -1966) and nss SO 4 2À spikes due to the most important volcanic events in the past (Pinatubo 1991, Agung 1963, Krakatoa 1883, Tambora 1815, Kuwae 1452, Unknown 1259). The number of annual layers recognized in the TD and ST556 cores was 779 and 97, respectively. The dD record obtained from the TD core has been compared with other East Antarctic isotope ice core records (Dome C EPICA, South Pole, Taylor Dome). These records suggest cooler climate conditions between the middle of 16th and the beginning of 19th centuries, which might be related to the Little Ice Age (LIA) cold period. Because of the high degree of geographical variability, the strongest LIA cooling was not temporally synchronous over East Antarctica, and the analyzed records do not provide a coherent picture for East Antarctica. The accumulation rate record presented for the TD core shows a decrease during part of the LIA followed by an increment of about 11% in accumulation during the 20th century. At the ST556 site, the accumulation rate observed during the 20th century was quite stable.INDEX TERMS: 3344

Spatial and temporal variability of snow chemical composition and accumulation rate at Talos Dome site (East Antarctica)

“…The stakes variability associated to the height of sastrugi (up to 20 cm) is probably suggesting that the time series based on TD core contains a random element caused by the surface irregularities that Fisher et al (1985) defines as "local noise". Stake measurements and sastrugi heights suggest that the annual local noise in snow accumulation can be ±30 mm w.e., which constitutes about 35% of the average annual accumulation (Stenni et al, 2002). Previous work by Frezzotti et al (2007) shows that the largest irregularity in snow morphology occurs in early summer whereas the minimum is recorded in late summer thus limiting the layering disturbance only to the summer season.…”

“…year −1 , evaluated over the 1217-1996 AD period (Stenni et al, 2002). Because of the relatively high accumulation rate, ice cores drilled at this site are considered to be suitable for highresolution records of past environmental and climatic variations.…”

“…The main goal of the TALDICE project was to obtain high-resolution chemical, isotopic and physical stratigraphies in an East Antarctic site located not far from the coast and characterized by a relatively high accumulation rate of about 80 mm water equivalent per year (here-hence w.e. year −1 ) as average 2004-1259 AD (Stenni et al, 2002). These features, together with its position on a geographical dome, are believed to allow reconstruction of the environmental and climatic changes occurring in the Ross SeaWilkes Land coast marine sector for the last 200 kyear and to allow a comparison of such stratigraphies with those obtained from the EPICA-Dome C and Taylor Dome ice cores (Bianchi et al, 2003;Frezzotti et al, 2004;Urbini et al, 2006).…”

Volcanic forcing of climate over the past 1500 years: An improved ice core‐based index for climate models

“…During the past 10 years a large number of new ice cores have been recovered, and most of these were analyzed using continuous sulfate measurements [Cole-Dai et al 1997Sommer et al 2000;Bigler et al 2002;Palmer et al 2002;Stenni et al 2002;Budner and Cole-Dai, 2003;Dixon et al 2004;Traufetter et al, 2004;Castellano et al, 2005;Kurbatov et al, 2006]. This offers the potential for a dramatic improvement to reconstruct the volcanic forcing index over the past centuries and millennia.…”

Anisotropy analysis of pressed point processes

“…The achieved drilling depth after the season 2006/2007 is about 1600 m, only slightly less than the predicted absolute ice thickness. The accumulation rate is estimated to about 100 mm water equivalent per year in the Thalos Dome region (Stenni et al (2002)). …”