Varying regional δ¹⁸O-temperature relationship in high resolution stable water isotopes from East Greenland

• Main Authors: Holme, Christian T, Gkinis, Vasileios, Lanzky, Mika, Morris, Valerie, Olesen, Martin, Thayer, Abigail, Vaughn, Bruce H, Vinther, Bo Møllesøe
• Format: Other/Unknown Material
• Language: English
• Published: PANGAEA 2019
• Subjects: Arctic Sea Ice and Greenland Ice Sheet Sensitivity; climate; diffusion; Greenland; ice2ice; paleoclimatology; Temperature; water isotopes; Arctic; Renland; East Greenland; Fram Strait; ice core; Ice Sheet; Iceland; North Atlantic; North Atlantic oscillation; Sea ice
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.901850; https://doi.org/10.1594/PANGAEA.901850

This study examines the stable water isotope signal (δ18O) of three ice cores drilled on the Renland peninsula (East Greenland coast). While ice core δ18O measurements qualitatively are a measure of the local temperature history, the δ18O variability in precipitation actually reflects the integrated hydrological activity that the deposited ice experienced from the evaporation source to the condensation site. Thus, as Renland is located next to a fluctuating sea ice cover, the transfer function used to infer past temperatures from the δ18O variability is potentially influenced by variations in the local moisture conditions. The objective of this study is therefore to evaluate the δ18O variability of ice cores drilled on Renland and examine what amount of the signal that can be attributed to regional temperature variations. In the analysis, three ice cores are utilized to create stacked summer, winter and annually averaged δ18O signals (AD 1801-2014). The imprint of temperature on δ18O is first examined by correlating the δ18O stacks with instrumental temperature records from East Greenland (AD 1895-2014) and Iceland (AD 1830-2014) and with the regional climate model HIRHAM5 (AD 1980-2014). The results show that the δ18O variability correlates with regional temperatures on both a seasonal and an annual scale between 1910-2014 while δ18O is uncorrelated with Iceland temperatures between 1830-1909. Our analysis indicates that the unstable regional δ18O-temperature correlation does not result from changes in weather patterns through respectively strengthening and weakening of the North Atlantic Oscillation. Instead, the results imply that the varying δ18O-temperature relation is connected with the volume flux of sea ice exported through Fram Strait (and south along the coast of East Greenland). Notably, the δ18O variability only reflects the variations in regional temperature when the temperature anomaly is positive and the sea ice export anomaly is negative. It is hypothesized that this could be caused by a larger ...