TY - JOUR
T1 - Coupled impacts of sea ice variability and North Pacific atmospheric circulation on Holocene hydroclimate in Arctic Alaska
AU - Broadman, Ellie
AU - Kaufman, Darrell S.
AU - Henderson, Andrew C.G.
AU - Malmierca-Vallet, Irene
AU - Leng, Melanie J.
AU - Lacey, Jack H.
N1 - Funding Information:
ACKNOWLEDGMENTS. We thank the US Fish and Wildlife Service, Arctic National Wildlife Refuge for use of the G. William Holmes research station and for permitting our research; Polar Field Services, Inc./CH2MHill for support and outfitting while in the field; Dirk Nickisch and Danielle Tirrell of Coyote Air for safely flying our field teams to and from the Lake Peters area; LacCore and the Continental Scientific Drilling Coordination Office for assistance with processing and archiving of sedimentary sequences; David Fortin for collecting the SP sediment core; Christopher Benson for sampling water in 2018; Rebecca Ellerbroek for analyzing the water samples at the Colorado Plateau Isotope Laboratory under the supervision of Jamie Brown, and for completing the HYSPLIT back-trajectory analyses; R. Scott Anderson for identifying 14C plant macrofossil samples; Katherine Whitacre and Chris Ebert for assisting with the preparation of the 14C samples; UC Irvine Keck Carbon Cycle Laboratory for analyzing the 14C samples; Daniel Cameron for completing the loss on ignition analysis; Matthew Ford and Sean Stahnke for assisting with the sedimentary biogenic silica analysis; Nicholas McKay for assistance with GeoChronR; and numerous field assistants who contributed to data collection in the Lake Peters area (https://arcticlakesproject.nau. edu/). This manuscript was improved following constructive suggestions from two anonymous reviewers. This project was funded by the National Science Foundation (Grant 1418000), and by the United Kingdom Natural Environment Research Council (Isotope Geosciences Facility Grant IP-1910-0619).
Publisher Copyright:
© 2020 National Academy of Sciences. All rights reserved.
PY - 2020/12
Y1 - 2020/12
N2 - Arctic Alaska lies at a climatological crossroads between the Arctic and North Pacific Oceans. The modern hydroclimate of the region is responding to rapidly diminishing sea ice, driven in part by changes in heat flux from the North Pacific. Paleoclimate reconstructions have improved our knowledge of Alaska’s hydroclimate, but no studies have examined Holocene sea ice, moisture, and ocean−atmosphere circulation in Arctic Alaska, limiting our understanding of the relationship between these phenomena in the past. Here we present a sedimentary diatom assemblage and diatom isotope dataset from Schrader Pond, located ∼80 km from the Arctic Ocean, which we interpret alongside synthesized regional records of Holocene hydroclimate and sea ice reduction scenarios modeled by the Hadley Centre Coupled Model Version 3 (HadCM3). The paleodata synthesis and model simulations suggest the Early and Middle Holocene in Arctic Alaska were characterized by less sea ice, a greater contribution of isotopically heavy Arctic-derived moisture, and wetter climate. In the Late Holocene, sea ice expanded and regional climate became drier. This climatic transition is coincident with a documented shift in North Pacific circulation involving the Aleutian Low at ∼4 ka, suggesting a Holocene teleconnection between the North Pacific and Arctic. The HadCM3 simulations reveal that reduced sea ice leads to a strengthened Aleutian Low shifted west, potentially increasing transport of warm North Pacific water to the Arctic through the Bering Strait. Our findings demonstrate the interconnectedness of the Arctic and North Pacific on multimillennial timescales, and are consistent with future projections of less sea ice and more precipitation in Arctic Alaska.
AB - Arctic Alaska lies at a climatological crossroads between the Arctic and North Pacific Oceans. The modern hydroclimate of the region is responding to rapidly diminishing sea ice, driven in part by changes in heat flux from the North Pacific. Paleoclimate reconstructions have improved our knowledge of Alaska’s hydroclimate, but no studies have examined Holocene sea ice, moisture, and ocean−atmosphere circulation in Arctic Alaska, limiting our understanding of the relationship between these phenomena in the past. Here we present a sedimentary diatom assemblage and diatom isotope dataset from Schrader Pond, located ∼80 km from the Arctic Ocean, which we interpret alongside synthesized regional records of Holocene hydroclimate and sea ice reduction scenarios modeled by the Hadley Centre Coupled Model Version 3 (HadCM3). The paleodata synthesis and model simulations suggest the Early and Middle Holocene in Arctic Alaska were characterized by less sea ice, a greater contribution of isotopically heavy Arctic-derived moisture, and wetter climate. In the Late Holocene, sea ice expanded and regional climate became drier. This climatic transition is coincident with a documented shift in North Pacific circulation involving the Aleutian Low at ∼4 ka, suggesting a Holocene teleconnection between the North Pacific and Arctic. The HadCM3 simulations reveal that reduced sea ice leads to a strengthened Aleutian Low shifted west, potentially increasing transport of warm North Pacific water to the Arctic through the Bering Strait. Our findings demonstrate the interconnectedness of the Arctic and North Pacific on multimillennial timescales, and are consistent with future projections of less sea ice and more precipitation in Arctic Alaska.
KW - Alaska hydroclimate
KW - Aleutian Low
KW - Arctic sea ice
KW - Holocene
KW - Oxygen isotopes
UR - http://www.scopus.com/inward/record.url?scp=85099172245&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85099172245&partnerID=8YFLogxK
U2 - 10.1073/PNAS.2016544117
DO - 10.1073/PNAS.2016544117
M3 - Article
C2 - 33288724
AN - SCOPUS:85099172245
SN - 0027-8424
VL - 117
SP - 33034
EP - 33042
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 52
ER -