Details:

Journal Title:
Paleoceanography and Paleoclimatology
Personal Author:
Moreno‐Chamarro, E. ; Ferreira, D. ; Marshall, J.
Moreno‐Chamarro, E. ; Ferreira, D. ; Marshall, J. Less -
NOAA Program & Office:
OAR (Oceanic and Atmospheric Research)
Description:
A 150‐ to 220‐year lag between abrupt Greenland warming and maximum Antarctic warming characterizes past glacial Dansgaard‐Oeschger events. In a modeling study, we investigate how the cross‐equatorial oceanic heat transport (COHT) might drive this phasing during an abrupt Northern Hemisphere (NH) warming. We use the MITgcm in an idealized continental configuration with two ocean basins, one wider, one narrower, under glacial‐like conditions with sea ice reaching midlatitudes. An exaggerated eccentricity‐related solar radiation anomaly is imposed over 100 years to trigger an abrupt NH warming and sea‐ice melting. The Hadley circulation shifts northward in response, weakening the NH trade winds, subtropical cells, and COHT in both ocean basins. This induces heat convergence in the Southern Hemisphere (SH) ocean subsurface, from where upward heat release melts sea ice and warms SH high latitudes. Although the small‐basin meridional overturning circulation also weakens, driven by NH ice melting, it contributes at most one‐third to the total COHT anomaly, hence playing a subsidiary role in the SH and NH initial warming. Switching off the forcing cools the NH; yet heat release continues from the SH ocean subsurface via isopycnal advection‐diffusion and vertical mixing, driving further sea ice melting and high latitude warming for ~50–70 more years. A phasing in polar temperatures resembling reconstructions thus emerges, linked to changes in the subtropical cells’ COHT, and SH ocean heat storage and surface fluxes. Our results highlight the potential role of the atmosphere circulation and wind‐driven global ocean circulation in the NH–SH phasing seen in DO events.
Keywords:
[+]
Atmospheric Science Oceanography Paleontology
Source:
Paleoceanography and Paleoclimatology, 35(7)
DOI:
https://doi.org/10.1029/2019pa003810
ISSN:
2572-4517;2572-4525;
Format:
PDF
Publisher:
American Geophysical Union (AGU)
Document Type:
Journal Article
Funding:
Grant no. NA16OAR4310177
Rights Information:
Other
Compliance:
Library
Main Document Checksum:
[+]
urn:sha256:18c1b76458c724f10cf0f66c9ed09dfae424bfa2558dd419677eea7e97d6b5f7
Download URL:
https://repository.library.noaa.gov/view/noaa/59762/noaa_59762_DS1.pdf
File Type:

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