Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
Clim. Past, 12, 2127-2143, 2016
https://doi.org/10.5194/cp-12-2127-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
28 Nov 2016
North Atlantic Oscillation controls on oxygen and hydrogen isotope gradients in winter precipitation across Europe; implications for palaeoclimate studies
Michael Deininger1, Martin Werner2, and Frank McDermott1,3 1UCD School of Earth Sciences, University College Dublin, Belfield, Dublin 4, Ireland
2Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Bussestraße 24, 27570 Bremerhaven, Germany
3UCD Earth Institute, University College Dublin, Belfield, Dublin 4, Ireland
Abstract. Winter (October to March) precipitation δ18OP and δDP values in central Europe correlate with the winter North Atlantic Oscillation index (wNAOi), but the causal mechanisms remain poorly understood. Here we analyse the relationships between precipitation-weighted δ18OP and δDP datasets (δ18Opw and δDpw) from European GNIP and ANIP stations and the wNAOi, with a focus on isotope gradients. We demonstrate that longitudinal δ18Opw and δDpw gradients across Europe (“continental effect”) depend on the wNAOi state, with steeper gradients associated with more negative wNAOi states. Changing gradients reflect a combination of air temperature and variable amounts of precipitable water as a function of the wNAOi. The relationships between the wNAOi, δ18Opw and δDpw can provide additional information from palaeoclimate archives such as European speleothems that primarily record winter δ18Opw. Comparisons between present-day and past European longitudinal δ18O gradients inferred from Holocene speleothems suggest that atmospheric pressure configurations akin to negative wNAO modes dominated the early Holocene, whereas patterns resembling positive wNAO modes were more common in the late Holocene, possibly caused by persistent shifts in the relative locations of the Azores High and the Icelandic Low.

Citation: Deininger, M., Werner, M., and McDermott, F.: North Atlantic Oscillation controls on oxygen and hydrogen isotope gradients in winter precipitation across Europe; implications for palaeoclimate studies, Clim. Past, 12, 2127-2143, https://doi.org/10.5194/cp-12-2127-2016, 2016.
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Short summary
This study investigates the NAO (Northern Atlantic Oscillation)-related mechanisms that control winter precipitation stable oxygen and hydrogen isotope gradients across Europe. The results show that past longitudinal stable oxygen and hydrogen isotope gradients in European rainfall stored in palaeoclimate archives (e.g. speleothems) can be used to infer the past winter NAO modes from its variations.
This study investigates the NAO (Northern Atlantic Oscillation)-related mechanisms that control...
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