Linear Weakening of the AMOC in response to Receding Glacial Ice Sheets in CCSM3


Contact
Xu.Zhang [ at ] awi.de

Abstract

The transient response of the Atlantic Meridional Overturning Circulation (AMOC) to a deglacial ice-sheet retreat is studied using the Community Climate System Model version 3 (CCSM3), with a focus on orographic effects rather than meltwater discharge. It is found that the AMOC weakens significantly (41%) in response to the deglacial ice-sheet retreat. The AMOC weakening follows the decrease of the Northern Hemisphere ice-sheet volume linearly, with no evidence of abrupt thresholds. A wind-driven mechanism is proposed to explain the weakening of the AMOC: lowering the Northern Hemisphere ice sheets induces a northward shift of the westerlies, which causes a rapid eastward sea-ice transport and expanded sea-ice cover over the subpolar North Atlantic; this expanded sea ice insulates the ocean from heat loss and leads to suppressed deep convection and a weakened AMOC. A sea ice-ocean positive feedback could be further established between the AMOC decrease and sea-ice expansion.



Item Type
Article
Authors
Divisions
Primary Division
Programs
Primary Topic
Peer revision
Peer-reviewed
Publication Status
Published
Eprint ID
36169
DOI 10.1002/2014GL060891

Cite as
Zhu, J. , Liu, Z. , Zhang, X. , Eisenman, I. and Liu, W. (2014): Linear Weakening of the AMOC in response to Receding Glacial Ice Sheets in CCSM3 , Geophysical Research Letters, 41 (17), pp. 6252-6258 . doi: 10.1002/2014GL060891


Download
[img]
Preview
PDF
2014gl060891.pdf

Download (1MB) | Preview
Cite this document as:

Share


Citation

Research Platforms
N/A

Campaigns


Actions
Edit Item Edit Item