North Atlantic simulations in Coordinated Ocean-ice Reference Experiments phase II (CORE-II). Part II: Inter-annual to decadal variability
|Author(s)||Danabasoglu Gokhan1, Yeager Steve G.1, Kim Who M.2, Behrens Erik3, Bentsen Mats4, Bi Daohua5, Biastoch Arne3, 9, Bleck Rainer7, 8, Boening Claus3, Bozec Alexandra, Canuto Vittorio M.8, Cassou Christophe10, Chassignet Eric9, Coward Andrew C.11, Danilov Sergey12, Diansky Nikolay13, Drange Helge14, 15, Farneti Riccardo16, Fernandez Elodie10, 17, Fogli Pier Giuseppe18, Forget Gael19, Fujii Yosuke20, Griffies Stephen M.21, Gusev Anatoly13, Heimbach Patrick19, Howard Armando8, 22, Ilicak Mehmet4, Jung Thomas12, Karspeck Alicia R.1, Kelley Maxwell8, Large William G.1, Leboissetier Anthony8, Lu Jianhua9, Madec Gurvan23, Marsland Simon J.5, 6, Masina Simona18, 24, Navarra Antonio18, 24, Nurser A. J. George11, Pirani Anna25, Romanou Anastasia8, 26, Salas Y Melia David27, Samuels Bonita L.21, Scheinert Markus3, Sidorenko Dmitry12, Sun Shan7, Treguier Anne-Marie28, Tsujino Hiroyuki20, Uotila Petteri5, 6, 29, Valcke Sophie10, Voldoire Aurore27, Wang Qiang12, Yashayaev Igor30|
|Affiliation(s)||1 : NCAR, Boulder, CO 80301 USA.
2 : Texas A&M Univ, College Stn, TX USA.
3 : Helmholtz Ctr Ocean Res, GEOMAR, Kiel, Germany.
4 : Bjerknes Ctr Climate Res, Uni Res Climate, Bergen, Norway.
5 : CSIRO, Ctr Australian Weather & Climate Res, Melbourne, Vic, Australia.
6 : CSIRO, Bur Meteorol, Melbourne, Vic, Australia.
7 : NOAA Earth Syst Res Lab, Boulder, CO USA.
8 : NASA Goddard Inst Space Studies GISS, New York, NY USA.
9 : Florida State Univ, Ctr Ocean Atmospher Predict Studies COAPS, Tallahassee, FL 32306 USA.
10 : CERFACS, Toulouse, France.
11 : NOCS, Southampton, Hants, England.
12 : Alfred Wegener Inst Polar & Marine Res AWI, Bremerhaven, Germany.
13 : Russian Acad Sci, Inst Numer Math, Moscow, Russia.
14 : Univ Bergen, Inst Geophys, Bergen, Norway.
15 : Bjerknes Ctr Climate Res, Bergen, Norway.
16 : Abdus Salaam Int Ctr Theoret Phys, Trieste, Italy.
17 : Mercator Ocean, Toulouse, France.
18 : Ctr Euromediterraneo Sui Cambiamenti Climatici CM, Bologna, Italy.
19 : MIT, Cambridge, MA 02139 USA.
20 : Japan Meteorol Agcy, MRI, Tsukuba, Ibaraki, Japan.
21 : NOAA Geophys Fluid Dynam Lab GFDL, Princeton, NJ USA.
22 : CUNY Medgar Evers Coll, Brooklyn, NY 11225 USA.
23 : CNRS IRD UPMC, IPSL LOCEAN, Paris, France.
24 : INGV, Bologna, Italy.
25 : Abdus Salaam Int Ctr Theoret Phys, Int CLIVAR Project Off, Trieste, Italy.
26 : Columbia Univ, New York, NY USA.
27 : Ctr Natl Rech Meteorol CNRM GAME, Toulouse, France.
28 : IUEM, CNRS Ifremer IRD UBO, UMR 6523, Lab Phys Oceans, Plouzane, France.
29 : Finnish Meteorol Inst, FIN-00101 Helsinki, Finland.
30 : Fisheries & Oceans Canada, Bedford Inst Oceanog, Dartmouth, NS B2Y 4A2, Canada.
|Source||Ocean Modelling (1463-5003) (Elsevier Sci Ltd), 2016-01 , Vol. 97 , P. 65-90|
|WOS© Times Cited||118|
|Keyword(s)||Global ocean - sea-ice modelling, Ocean model comparisons, Atmospheric forcing, Inter-annual to decadal variability and mechanisms, Atlantic meridional overturning circulation variability, Variability in the North Atlantic|
|Abstract||Simulated inter-annual to decadal variability and trends in the North Atlantic for the 1958-2007 period from twenty global ocean - sea-ice coupled models are presented. These simulations are performed as contributions to the second phase of the Coordinated Ocean-ice Reference Experiments (CORE-II). The study is Part II of our companion paper (Danabasoglu et al., 2014) which documented the mean states in the North Atlantic from the same models. A major focus of the present study is the representation of Atlantic meridional overturning circulation (AMOC) variability in the participating models. Relationships between AMOC variability and those of some other related variables, such as subpolar mixed layer depths, the North Atlantic Oscillation (NAO), and the Labrador Sea upper-ocean hydrographic properties, are also investigated. In general, AMOC variability shows three distinct stages. During the first stage that lasts until the mid-to late-1970s, AMOC is relatively steady, remaining lower than its long-term (1958-2007) mean. Thereafter, AMOC intensifies with maximum transports achieved in the mid-to late-1990s. This enhancement is then followed by a weakening trend until the end of our integration period. This sequence of low frequency AMOC variability is consistent with previous studies. Regarding strengthening of AMOC between about the mid-1970s and the mid-1990s, our results support a previously identified variability mechanism where AMOC intensification is connected to increased deep water formation in the subpolar North Atlantic, driven by NAO-related surface fluxes. The simulations tend to show general agreement in their temporal representations of, for example, AMOC, sea surface temperature (SST), and subpolar mixed layer depth variabilities. In particular, the observed variability of the North Atlantic SSTs is captured well by all models. These findings indicate that simulated variability and trends are primarily dictated by the atmospheric datasets which include the influence of ocean dynamics from nature superimposed onto anthropogenic effects. Despite these general agreements, there are many differences among the model solutions, particularly in the spatial structures of variability patterns. For example, the location of the maximum AMOC variability differs among the models between Northern and Southern Hemispheres.|