High-frequency climate variability in the Holocene from a coastal-dome ice core in east-central Greenland

• Main Authors: Hughes, Abigail G., Jones, Tyler R., Vinther, Bo M., Gkinis, Vasileios, Stevens, C. Max, Morris, Valerie, Vaughn, Bruce H., Holme, Christian, Markle, Bradley R., White, James W. C.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: European Geosciences Union 2020
• Subjects: Arctic; Greenland; Renland; Climate change; Greenland ice cores; Ice cap; ice core; North Atlantic; Sea ice
• Online Access: https://doi.org/10.5194/cp-16-1369-2020

An ice core drilled on the Renland ice cap in east-central Greenland contains a continuous climate record dating through the last glacial period. The Renland record is valuable because the coastal environment is more likely to reflect regional sea surface conditions compared to inland Greenland ice cores that capture synoptic variability. Here we present the δ¹â¸O water isotope record for the Holocene, in which decadal-scale climate information is retained for the last 8 kyr, while the annual water isotope signal is preserved throughout the last 2.6 kyr. To investigate regional climate information preserved in the water isotope record, we apply spectral analysis techniques to a 300-year moving window to determine the mean strength of varying frequency bands through time. We find that the strength of 15–20-year δ¹â¸O variability exhibits a millennial-scale signal in line with the well-known Bond events. Comparison to other North Atlantic proxy records suggests that the 15–20-year variability may reflect fluctuating sea surface conditions throughout the Holocene, driven by changes in the strength of the Atlantic Meridional Overturning Circulation. Additional analysis of the seasonal signal over the last 2.6 kyr reveals that the winter δ¹â¸O signal has experienced a decreasing trend, while the summer signal has predominantly remained stable. The winter trend may correspond to an increase in Arctic sea ice cover, which is driven by a decrease in total annual insolation, and is also likely influenced by regional climate variables such as atmospheric and oceanic circulation. In the context of anthropogenic climate change, the winter trend may have important implications for feedback processes as sea ice retreats in the Arctic. © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Published by Copernicus Publications on behalf of the European Geosciences Union. Received: 11 Feb 2020 – Discussion started: 24 Feb 2020 – Accepted: 06 Jun 2020 – Published: ...