caa a22 4500 605474133 CHVBK 20210128100346.0 cr unu---uuuuu 210128e20150101xx s 000 0 eng 10.1007/s00382-014-2395-y doi (NATIONALLICENCE)springer-10.1007/s00382-014-2395-y Climate drift of AMOC, North Atlantic salinity and arctic sea ice in CFSv2 decadal predictions [Elektronische Daten] [Bohua Huang, Jieshun Zhu, Lawrence Marx, Xingren Wu, Arun Kumar, Zeng-Zhen Hu, Magdalena Balmaseda, Shaoqing Zhang, Jian Lu, Edwin Schneider, James Kinter III] There are potential advantages to extending operational seasonal forecast models to predict decadal variability but major efforts are required to assess the model fidelity for this task. In this study, we examine the North Atlantic climate simulated by the NCEP Climate Forecast System, version 2 (CFSv2), using a set of ensemble decadal hindcasts and several 30-year simulations initialized from realistic ocean-atmosphere states. It is found that a substantial climate drift occurs in the first few years of the CFSv2 hindcasts, which represents a major systematic bias and may seriously affect the model's fidelity for decadal prediction. In particular, it is noted that a major reduction of the upper ocean salinity in the northern North Atlantic weakens the Atlantic meridional overturning circulation (AMOC) significantly. This freshening is likely caused by the excessive freshwater transport from the Arctic Ocean and weakened subtropical water transport by the North Atlantic Current. A potential source of the excessive freshwater is the quick melting of sea ice, which also causes unrealistically thin ice cover in the Arctic Ocean. Our sensitivity experiments with adjusted sea ice albedo parameters produce a sustainable ice cover with realistic thickness distribution. It also leads to a moderate increase of the AMOC strength. This study suggests that a realistic freshwater balance, including a proper sea ice feedback, is crucial for simulating the North Atlantic climate and its variability. Springer-Verlag Berlin Heidelberg, 2014 Climate drift nationallicence Decadal prediction nationallicence Atlantic meridional overturning circulation nationallicence North Atlantic salinity nationallicence Arctic sea ice nationallicence Huang Bohua Department of Atmospheric, Oceanic and Earth Sciences, College of Science, George Mason University, Mail Stop 6C5, 4400 University Drive, 22030, Fairfax, VA, USA aut Zhu Jieshun Center for Ocean-Land-Atmosphere Studies, Fairfax, VA, USA aut Marx Lawrence Center for Ocean-Land-Atmosphere Studies, Fairfax, VA, USA aut Wu Xingren Environmental Modeling Center, National Centers for Environmental Prediction/NOAA, College Park, MD, USA aut Kumar Arun Climate Prediction Center, National Centers for Environmental Prediction/NOAA, College Park, MD, USA aut Hu Zeng-Zhen Climate Prediction Center, National Centers for Environmental Prediction/NOAA, College Park, MD, USA aut Balmaseda Magdalena European Centre for Medium-Range Weather Forecasts, Reading, UK aut Zhang Shaoqing Geophysical Fluid Dynamics Laboratory/NOAA, Princeton University, Princeton, NJ, USA aut Lu Jian Pacific Northwest National Laboratory, Richland, WA, USA aut Schneider Edwin Department of Atmospheric, Oceanic and Earth Sciences, College of Science, George Mason University, Mail Stop 6C5, 4400 University Drive, 22030, Fairfax, VA, USA aut Kinter III James Department of Atmospheric, Oceanic and Earth Sciences, College of Science, George Mason University, Mail Stop 6C5, 4400 University Drive, 22030, Fairfax, VA, USA aut Climate Dynamics Springer Berlin Heidelberg 44/1-2(2015-01-01), 559-583 0930-7575 44:1-2<559 2015 44 382 https://doi.org/10.1007/s00382-014-2395-y text/html Onlinezugriff via DOI BK010053 XK010053 XK010000 Metadata rights reserved Springer special CC-BY-NC licence nationallicence 1 research-article jats NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE 856 40 https://doi.org/10.1007/s00382-014-2395-y text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Huang Bohua Department of Atmospheric, Oceanic and Earth Sciences, College of Science, George Mason University, Mail Stop 6C5, 4400 University Drive, 22030, Fairfax, VA, USA aut NATIONALLICENCE 700 1- Zhu Jieshun Center for Ocean-Land-Atmosphere Studies, Fairfax, VA, USA aut NATIONALLICENCE 700 1- Marx Lawrence Center for Ocean-Land-Atmosphere Studies, Fairfax, VA, USA aut NATIONALLICENCE 700 1- Wu Xingren Environmental Modeling Center, National Centers for Environmental Prediction/NOAA, College Park, MD, USA aut NATIONALLICENCE 700 1- Kumar Arun Climate Prediction Center, National Centers for Environmental Prediction/NOAA, College Park, MD, USA aut NATIONALLICENCE 700 1- Hu Zeng-Zhen Climate Prediction Center, National Centers for Environmental Prediction/NOAA, College Park, MD, USA aut NATIONALLICENCE 700 1- Balmaseda Magdalena European Centre for Medium-Range Weather Forecasts, Reading, UK aut NATIONALLICENCE 700 1- Zhang Shaoqing Geophysical Fluid Dynamics Laboratory/NOAA, Princeton University, Princeton, NJ, USA aut NATIONALLICENCE 700 1- Lu Jian Pacific Northwest National Laboratory, Richland, WA, USA aut NATIONALLICENCE 700 1- Schneider Edwin Department of Atmospheric, Oceanic and Earth Sciences, College of Science, George Mason University, Mail Stop 6C5, 4400 University Drive, 22030, Fairfax, VA, USA aut NATIONALLICENCE 700 1- Kinter III James Department of Atmospheric, Oceanic and Earth Sciences, College of Science, George Mason University, Mail Stop 6C5, 4400 University Drive, 22030, Fairfax, VA, USA aut NATIONALLICENCE 773 0- Climate Dynamics Springer Berlin Heidelberg 44/1-2(2015-01-01), 559-583 0930-7575 44:1-2<559 2015 44 382