Sensitivity of AMOC Fingerprints Under Future Anthropogenic Warming

Abstract

Detecting the response of the Atlantic meridional overturning circulation (AMOC) to anthropogenic warming can only be made with fingerprints indirectly because of the lack of sufficiently long direct measurements. However, whether the relationship between the AMOC and its fingerprints is stationary is rarely examined. This study uses coupled and ocean-alone model simulations to investigate the sensitivity of two typical AMOC fingerprints under future anthropogenic warming. We found a lower sensitivity of the North Atlantic warming hole fingerprint in future warming scenarios associated with the differing vulnerability of deep-water origins to external forcing and climate feedback. In contrast, the remote South Atlantic salinity pile-up fingerprint is relatively insensitive to variations in AMOC sources, and its sensitivity to the AMOC is slightly enhanced by an intensified hydrological cycle. Our study implies that fingerprints outside the northern deep convection region may become more suitable in representing the response of AMOC to future warming.