Tree rings, ice cores and borehole thermometry are among the main sources for temperature reconstructions in the Arctic and Subarctic regions in the Late Holocene (Overpeck et al, 1997). The annual-resolution reconstructions based on tree rings are most accurate in terms of dating and high frequency variations, whereas boreholes and tree line variations provide long-term temperature trends. The accuracy of ice core chronologies can be close to annual, but it has to be checked, due to possible hiatus in the records. On the other hand different records can reflect different seasonal climatic parameters, or contain local climatic and non-climatic «noise».

In this study we compare different kind of Late Holocene proxy records from three regions in the Russian Arctic and Subarctic: the Polar Urals (Shiyatov, 2000) and Franz Josef Land (Henderson, 2002); Taimyr (Hantemirov, Shiyatov, 2002) and Severnaya Zemlya (Kotlyakov et al, 2004), and Kamchatka (Shiraiwa et al, 2001; Solomina et al, 2000) in order to estimate the accuracy of the ice-core chronologies, and the agreement between different proxy records, including the long term versus short term variations. Checking the accuracy of ice-core chronologies we use the procedure similar to the tree ring cross-dating (Fritts, 1976) comparing different ice core parameters (Melt Feature Index, δ¹⁸O, SO₄2-, NO₃-, C1-) and five types of longest temperature sensitive tree ring chronologies: ring width, width of early and late wood, maximum and minimum density. We found out that the minima of Melt feature index is the most useful chronological parameter allowing detection of a hiatus in the ice core chronologies. Borehole temperature reconstructions (Demezhko et al, 2003) fit very well with the temperature reconstructions of the last millennium in the Polar Urals based on tree rings and the upper tree line (Shiyatov, 2000), although correlation with the ice-core chronology is more problematic. The analysis of modern meteorological records shows a very weak correlation between temperatures in the Franz Josef Land and the Urals-Taimyr areas, which can be the reason for this disagreement between the ice-core and tree-ring records.

The project is funded by ISTC grant #2947.

Reference:

Solomina O., Nagornov O., Mikhalenko V., Kutuzov S. Do ice-core, tree-ring and borehole temperature proxies agree in the Russian Arctic and Subarctic? Correlation of Pleistocene Events in the Russian North. International Workshop Abstracts. 4-6 December 2006. Saint-Petersburg, 2006, p. 94.