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

Climate of the Past Discussions

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Hughes, Abigail G.¹  White, James W. C.¹  Jones, Tyler R.¹  Vinther, Bo M.²  Gkinis, Vasileios²  Stevens, C. Max³  Morris, Valerie¹  Vaughn, Bruce H.¹  Holme, Christian²  Markle, Bradley R.¹ 

[1] Institute of Arctic and Alpine Research, University of Colorado Boulder;Niels Bohr Institute, University of Copenhagen;Department of Earth and Space Sciences, University of Washington;California Institute of Technology

DOI  :  10.5194/cp-16-1369-2020

学科分类：大气科学

来源: Copernicus Publications

【 摘 要 】

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 δ 18 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 δ 18 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 δ 18 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.

【 授权许可】

CC BY