Publication Abstracts

Lin et al. 2023

Lin, Y.-J., B.E.J. Rose, and Y.-T. Hwang, 2023: Mean state AMOC affects AMOC weakening through subsurface warming in the Labrador Sea. J. Climate, 36, no. 12, 3895-3915, doi:10.1175/JCLI-D-22-0464.1.

While most models agree that the Atlantic Meridional Overturning Circulation (AMOC) becomes weaker under greenhouse gas emission and is likely to weaken over the 21st century, they disagree on the projected magnitudes of AMOC weakening. In this work, CMIP6 models with stronger climatological AMOC are shown to project stronger AMOC weakening in both 1 percent ramping CO2 and abrupt CO2 quadrupling simulations. A physical interpretation of this result is developed. For models with stronger mean state AMOC, stratification in the upper Labrador Sea is weaker, allowing for stronger mixing of the surface buoyancy flux. In response to CO2 increase, surface warming is mixed to the deeper Labrador Sea in models with stronger upper ocean mixing. This subsurface warming and corresponding density decrease drives AMOC weakening through advection from the Labrador Sea to the subtropics via the Deep Western Boundary Current. Time series analysis shows that most CMIP6 models agree that the decrease in subsurface Labrador Sea density leads AMOC weakening in the subtropics by several years. Also, idealized experiments conducted in an ocean-only model show that the subsurface warming over 500-1500 m in the Labrador Sea leads to stronger AMOC weakening several years later, while the warming that is too shallow (<500 m) or too deep (>1500 m) in Labrador Sea causes little AMOC weakening. These results suggest that a better representation of mean state AMOC is necessary for narrowing the inter-model uncertainty of AMOC weakening to greenhouse gas emission and its corresponding impacts on future warming projections.

Export citation: [ BibTeX ] [ RIS ]

BibTeX Citation

  author={Lin, Y.-J. and Rose, B. E. J. and Hwang, Y.-T.},
  title={Mean state AMOC affects AMOC weakening through subsurface warming in the Labrador Sea},
  journal={Journal of Climate},

[ Close ]

RIS Citation

ID  - li05310f
AU  - Lin, Y.-J.
AU  - Rose, B. E. J.
AU  - Hwang, Y.-T.
PY  - 2023
TI  - Mean state AMOC affects AMOC weakening through subsurface warming in the Labrador Sea
JA  - J. Climate
JO  - Journal of Climate
VL  - 36
IS  - 12
SP  - 3895
EP  - 3915
DO  - 10.1175/JCLI-D-22-0464.1
ER  -

[ Close ]

• Return to 2023 Publications

• Return to Publications Homepage