title: Atlantic Meridional Overturning Circulation slowdown cooled the subtropical ocean.
abstract: [1] Observations show that the upper 2 km of the subtropical North Atlantic Ocean cooled throughout 2010 and remained cold until at least December 2011. We show that these cold anomalies are partly driven by anomalous air-sea exchange during the cold winters of 2009/2010 and 2010/2011 and, more surprisingly, by extreme interannual variability in the ocean's northward heat transport at 26.5°N. This cooling driven by the ocean's meridional heat transport affects deeper layers isolated from the atmosphere on annual timescales and water that is entrained into the winter mixed layer thus lowering winter sea surface temperatures. Here we connect, for the first time, variability in the northward heat transport carried by the Atlantic Meridional Overturning Circulation to widespread sustained cooling of the subtropical North Atlantic, challenging the prevailing view that the ocean plays a passive role in the coupled ocean-atmosphere system on monthly-to-seasonal timescales.
authors.affiliation: Now at Scottish Association for Marine Science, Scottish Marine Institute Oban, UK ; National Oceanography Centre Southampton, UK.
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Cunningham
authors.affiliation: Met Office Hadley Centre Exeter, UK.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Roberts
authors.affiliation: National Oceanography Centre, University of Southampton Waterfront Campus Southampton, UK.
authors.forename: Eleanor
authors.initials: E
authors.lastname: Frajka-Williams
authors.affiliation: Rosenstiel School of Marine and Atmospheric Science, University of Miami Miami, Florida, USA.
authors.forename: William E
authors.initials: WE
authors.lastname: Johns
authors.affiliation: Institute for Marine and Antarctic Studies, ARC Centre of Excellence for Climate System Science, University of Tasmania Hobart, Tasmania, Australia.
authors.forename: Will
authors.initials: W
authors.lastname: Hobbs
authors.affiliation: Met Office Hadley Centre Exeter, UK.
authors.forename: Matthew D
authors.initials: MD
authors.lastname: Palmer
authors.affiliation: National Oceanography Centre Southampton, UK.
authors.forename: Darren
authors.initials: D
authors.lastname: Rayner
authors.affiliation: National Oceanography Centre Southampton, UK.
authors.forename: David A
authors.initials: DA
authors.lastname: Smeed
authors.affiliation: National Oceanography Centre Southampton, UK.
authors.forename: Gerard
authors.initials: G
authors.lastname: McCarthy