Ice cores are one of the best archives for climate and environmental changes. A new 724 m deep ice core was drilled on Akademii Nauk ice cap (Severnaya Zemlya) between 1999 and 2001 to gain high resolution proxy data from the Central Russian Arctic. The Akademii Nauk ice core contains significant proxy data for the reconstruction of climate and environmental changes, although the ice cap is affected by summerly melting and infiltration processes, resulting in alteration of the original isotopic and chemical signals.Here we present overview data (bag mean values: 0.3-1.0 m) of stable water isotopes (δ18O, d) and major ions of the uppermost 530 m as well as high resolution data for some special sections. Dating of this ice core is based on reference layers (nuclear weapon tests, volcanoes) and on counting of annual cycles of stable isotopes and electrical conductivity. The age model yielded an age of about 1.500 years for the core section viewed here.δ18O data reflect Eurasian Arctic surface air temperature (SAT) changes and show a generally decreasing trend, culminating in the absolute SAT minimum around 1800. Thereafter the values increased strongly to the absolute maximum around 1930. The decreasing isotopic trend is at least partly caused by the growth of Akademii Nauk ice cap. This is also reflectedin the annual layer thickness data and a decreasing overall trend of sea salt ions, which reached their lowest values also around 1800. In contrast, there is no clear trend in ammonium and nitrate observable.After 1800 almost all ions show increasing concentrations until the mid-20th century, followed by a repeated decline in the last decades. The 20th century record is superimposed by the anthropogenic pollution of the Arctic, mainly visible in strong increasing levels of sulphate and nitrate after World War II with highest concentration from the 1960ies to the 1980ies and again decreasing values thereafter.Some of the sharp sulphate peaks could be attributed to certain volcanic eruptions, e.g. Laki/Iceland (1783) and Bezymianny/Kamchatka (1956).
Helmholtz Research Programs > MARCOPOLI (2004-2008) > POL6-Earth climate variability since the Pliocene