Asymmetric changes in temperature in the Arctic during the Holocene based on a transient run with the Community Earth System Model (CESM)
<p>The Arctic temperature changes are closely linked to midlatitude weather variability and extreme events, which has attracted much attention in recent decades. Syntheses of proxy data from poleward of 60<span class="inline-formula"><sup>∘</sup></span> N ind...
Main Authors: | , , , , , |
---|---|
Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2023-03-01
|
Series: | Climate of the Past |
Online Access: | https://cp.copernicus.org/articles/19/665/2023/cp-19-665-2023.pdf |
Summary: | <p>The Arctic temperature changes are closely linked to
midlatitude weather variability and extreme events, which has attracted much
attention in recent decades. Syntheses of proxy data from poleward of
60<span class="inline-formula"><sup>∘</sup></span> N indicate that there was asymmetric cooling of
<span class="inline-formula">−1.54</span> and <span class="inline-formula">−0.61</span> <span class="inline-formula"><sup>∘</sup></span>C for the Atlantic Arctic and the Pacific Arctic
during the Holocene, respectively. We also present a similar consistent
cooling pattern from an accelerated transient Holocene climate simulation
based on the Community Earth System Model. Our results indicate that the
asymmetric Holocene Arctic cooling trend is dominated by the winter
temperature variability, with <span class="inline-formula">−0.67</span> <span class="inline-formula"><sup>∘</sup></span>C cooling for the Atlantic Arctic
and 0.09 <span class="inline-formula"><sup>∘</sup></span>C warming for the Pacific Arctic, which is particularly
pronounced at the proxy sites. Our findings indicate that sea ice in the
North Atlantic expanded significantly during the late Holocene, while a sea
ice retreat is seen in the North Pacific, amplifying the cooling in the
Atlantic Arctic by the sea ice feedback. The positive Arctic dipole pattern,
which promotes warm southerly winds to the North Pacific, offsets parts of
the cooling trend in the Pacific Arctic. The Arctic dipole pattern also causes
sea ice expansion in the North Atlantic, further amplifying the cooling
asymmetry. We found that the temperature asymmetry is more pronounced in a
simulation driven only by orbital forcing. The accelerated simulations lead
to a partial delay in the feedback of climate processes. Therefore, we
confirm the occurrence of the asymmetry of the Arctic temperature changes in
un-accelerated simulations using ECBilt-CLIO, IPSL, and in TraCE-21k.</p> |
---|---|
ISSN: | 1814-9324 1814-9332 |