Spatial variability in the European winter precipitation δ18O-NAO relationship:: Implications for reconstructing NAO-mode climate variability in the Holocene

This paper investigates the links between precipitation delta O-18 and the North Atlantic Oscillation (NAO) on decadal timescales to identify the optimum locations within Europe at which to compile delta O-18-based proxy records of past NAO variability. delta O-18 is a commonly used paleoclimate (rainfall and temperature) proxy preserved in natural archives including stalagmites, ice cores, tree rings, and lake sediments. Precipitation delta O-18 data (delta O-18(p)), compiled from Global Network of Isotopes in Precipitation (GNIP) stations in the North Atlantic sector reveal the direction and strength of the delta O-18(p)-NAO relationship in mid-latitude, high-latitude, and Mediterranean Europe. The highly significant, positive delta O-18(p)-NAO relationship in central Europe is attributed to the strong control of air temperature on delta O-18(p) in this region. The delta O-18(p)-NAO relationship is strongly negative at high-latitude GNIP sites and weak at Mediterranean sites. Decadal-scale solar irradiance variations correlate with winter delta O-18(p) at eight midlatitude sites.