TY - JOUR

T1 - High-frequency climate variability in the Holocene from a coastal-dome ice core in east-central Greenland

AU - Hughes, Abigail G.

AU - Jones, Tyler R.

AU - Vinther, Bo M.

AU - Gkinis, Vasileios

AU - Stevens, C. Max

AU - Morris, Valerie

AU - Vaughn, Bruce H.

AU - Holme, Christian

AU - Markle, Bradley R.

AU - White, James W. C.

PY - 2020/7/31

Y1 - 2020/7/31

N2 - An ice core drilled on the Renland ice cap in eastcentral 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 delta O-18 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 delta O-18 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 delta O-18 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.

AB - An ice core drilled on the Renland ice cap in eastcentral 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 delta O-18 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 delta O-18 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 delta O-18 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.

KW - STABLE WATER ISOTOPES

KW - NORTH-ATLANTIC CLIMATE

KW - SURFACE MASS-BALANCE

KW - SEA-ICE

KW - ARCTIC-OCEAN

KW - DIFFUSION

KW - SHEET

KW - TEMPERATURE

KW - PRECIPITATION

KW - TRANSPORT

U2 - 10.5194/cp-16-1369-2020

DO - 10.5194/cp-16-1369-2020

M3 - Journal article

VL - 16

SP - 1369

EP - 1386

JO - Climate of the Past

JF - Climate of the Past

SN - 1814-9324

IS - 4

ER -