Glaciological studies at Siple Station (Antarctica): potential ice-core paleoclimatic record

Abstract

ABSTRACT. The quality and utility of the records of oxygen-isotopic ab undances, dust concentrations and anionic concentrations preserved in the ice at Siple Station (75°55' S, 84° IS' W) are assessed from four shallow (20 m) cores. The combination of high accum ul ation (0.56 m a-I w.e. ) and low mean a nnu al temperature (-24°C) preserves the prominent seasonal variations in 8 18 0 which are very spatially coherent. Sulfate co ncent rations vary seaso nally and, in conjunction with 8 18 0, will allow accurate dating of dee per cores from Siple Station. The concentrations of insoluble dust are the lowest measu red in Antarctica, making Siple Station an excellent location to exam ine large increases in atmospheric tubidity.Th e seasonal variations and annual flux es of the anions are examined for the last two decades (AD 1966-85 ) Finally, co mparison of the 8 18 0 record with available surface-temperature d a ta (AD 1957-85 ) reveals that multi-year trends along the western coast of the Antarctic Peninsula are reco rd ed at Siple. More importantly, comparison with areally weighted tem perature reconstructions suggests that the 8 18 0 record may reflect larger-scale, persistent tren ds in the high southern latitudes. The strong spatial coherence of the preserved reco rds, the potential for accurate dating, and possible relevance to largerscale processes make Siple Station an excellent site for paleo environmental reconstruction from ice co res.

An assessment and interpretation of the observed warming of West Antarctica in the austral spring

“…1977 stands out as the coldest year of the entire record for both EAIS and WAIS for all of the datasets. Prior to this, persistent warmth occurred from 1970 to 1975, a prominent anomaly that has been noted before (Schwerdtfeger 1976;Mosley-Thompson et al 1991) and is consistent with positive anomalies of atmospheric mass over the Antarctic (Swanson and Trenberth 1981), and with positive oxygen isotope anomalies in West Antarctic ice cores (Mosley- Thompson et al 1991). The increase in atmospheric mass over Antarctica from the early 1960s to the early 1970s discussed by Swanson and Trenberth (1981) is physically consistent with the upward temperature trends of the early part of these records.…”

Retrieving snowpack properties and accumulation estimates from a combination of SAR and scatterometer measurements

“…The largest connected areas of this kind are found in West Antarctica, i.e., Marie Byrd Land (100 -140 W), Ellsworth Land (80 to 100 W), and Palmer Land (65 W). In agreement for both frequencies, the lowest values of (Escat dB/Nscat dB) are observed in Marie Byrd Land at two locations within the Executive Committee Range between 76 30'S and 77 S at 121 W and 132 W, where an accumulation maximum of 560 kg m a has been reported by [29]. Scattered areas are found in DML, where values of up to 593 kg m a In east Antarctica striking patterns are generated by regions of strong katabatic air flow, which causes a higher surface roughness.…”

Evidence for an 11-Year Cycle of Atmospheric H₂O₂ Fluctuation Recorded in an Ice Core at the Coastal Region, East Antarctica

“…Therefore, for the dating of the core, we adopted the counting method of the seasonal variations of chemical species. Here, a clear annual cycle was observed, especially for nssSO42-(sulfate not from sea salt), as was already reported in many ice cores (Mosley- Thompson et al, 1991;Peel and Mulvaney, 1992;Langway et al, 1994). The mean annual net accumulation rate of snow at S25, based on this counting, was estimated to be about 300kg m-2, showing similarity to the result of stake measurements of snow.…”