Atmospheric drivers that compromise the assumed long-term stationarity between δ18O-based proxy records and NAO, winter air temperature and winter precipitation amount.

Laia Comas-Bru, University College Dublin, UCD School of Earth Sciences, Dublin, Ireland, Frank Patrick McDermott, University College Dublin, UCD School of Earth Sciences, Belfield, Dublin 4, Dublin, Ireland and Martin Werner, Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Bremerhaven, Bremerhaven, Germany