Impact of the Atlantic Meridional Overturning Circulation (AMOC) on Arctic Surface Air Temperature and Sea-Ice Variability by Salil Mahajan, Rong Zhang & Thomas L. Delworth, J. Climate (2011)

Journal of Climate (2011); doi: 10.1175/2011JCLI4002.1

Impact of the Atlantic Meridional Overturning Circulation (AMOC) on Arctic Surface Air Temperature and Sea-Ice Variability

Salil Mahajan^*

Atmospheric and Oceanic Sciences Program, Princeton University, Princeton, NJ, U.S.A.

Rong Zhang and Thomas L. Delworth

Geophysical Fluid Dynamics Laboratory, Princeton, NJ, U.S.A.

Abstract

The simulated impact of the Atlantic Meridional Overturning Circulation (AMOC) on the low-frequency variability of the Arctic Surface Air temperature (SAT) and sea-ice extent is studied with a 1,000-year-long segment of a control simulation of GFDL CM2.1 climate model. The simulated AMOC variations in the control simulation are found to be significantly anti-correlated with the Arctic sea-ice extent anomalies and significantly correlated with the Arctic SAT anomalies on decadal timescales in the Atlantic sector of the Arctic. The maximum anti-correlation with the Arctic sea-ice extent and the maximum correlation with the Arctic SAT occur when the AMOC Index leads by one year. An intensification of the AMOC is associated with a sea-ice decline in the Labrador, Greenland and Barents Seas in the control simulation, with the largest change occurring in the winter. The recent declining trend in the satellite observed sea-ice extent also shows a similar pattern in the Atlantic sector of the Arctic in the winter, suggesting the possibility of a role of the AMOC in the recent Arctic sea-ice decline in addition to anthropogenic greenhouse gas induced warming. However, in the summer, the simulated sea-ice response to the AMOC in the Pacific sector of the Arctic is much weaker than the observed declining trend, indicating a stronger role for other climate forcings or variability in the recently observed summer sea-ice decline in the Chukchi, Beaufort, East Siberian and Laptev Seas.

^*Correspondence: Salil Mahajan, 300 Forrestal Road, Sayre Hall, Atmospheric and Oceanic Sciences Program, Princeton University, Princeton, NJ 08544, U.S.A. e-mail: smahajan@princeton.edu

http://journals.ametsoc.org/doi/abs/10.1175/2011JCLI4002.1