Linking the inter-basin climate variability through the overturning circulation

Tuesday, December 10, 2019 - 14:10
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Although the Atlantic Meridional Overturning Circulation (AMOC) is thought to be a global scale ocean circulation, AMOC variations and the associated impacts on inter-basin climate mode variability are still not well understood. Here, by analyzing a set of simulations using the Community Earth System Model version 1 (CESM1), we explore how significant changes in AMOC would affect the inter-basin connections of the ocean circulation and the decadal mode variability in different ocean basins. It is found that a collapsed AMOC would induce a reorganization of the global ocean circulations, such as a weakening of the Bering Strait throughflow and the Indonesian throughflow, but a strengthening of the Antarctic circumpolar current. Resulting from these changes, the decadal mode in the Pacific weakens overall with a strengthened variability in the subpolar region. On the other hand, the Atlantic multi-decadal variability strengthens in the subpolar Northeast Atlantic, but weakens a bit in the subtropical Atlantic. Our results suggest that changes in AMOC affect not only the ocean circulations, but also the surface decadal climate variability.

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