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Shallow firn cores from Neumayer, Ekströmisen, Antarctica: a comparison of accumulation rates and stable-isotope ratios

2002; Cambridge University Press; Volume: 35; Linguagem: Inglês

10.3189/172756402781816915

1727-5644

Elisabeth Schlosser, Hans Oerter,

Geology and Paleoclimatology Research

Abstract Since 1979/80, glaciological studies have been carried out at Ekströmisen, Antarctica, including accumulation-stake measurements, snow-pit and shallow-firn-core studies. Snow stratigraphy, chemical properties and stable-isotope ratios (δ 18 O) were investigated. This study focuses on three cores taken between 1982 and 1998. the 1998 core was dated using dielectric profiling, δ 18 O profiles and stake measurements. Accumulation rates show high interannual and spatial variability due to the extreme wind influence. No significant trend was found for the last 50 years; during the first half of the 20th century, accumulation decreased. the high spatial and interannual variability, however, means that trends must be interpreted with care. In spite of the highly irregular accumulation distribution, stable-isotope ratios show little spatial variability. the mean annual δ 18 O values of cores B04 and FB0198 agree fairly well for the time period 1955–82 covered by both cores. δ 18 O values have increased during most of the 20th century; since the late 1980s a decrease is observed. This change is not related to air temperature, since mean annual air temperatures at Neumayer show no significant trend over the last two decades.