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Author Calafat, FM; Chambers, DP
Title Inter-annual to decadal sea level variability in the coastal zones of the Norwegian and Siberian Seas: the role of atmospheric forcing Type Journal Article
Year 2013 Publication Journal of Geophysical Research Abbreviated Journal J. Geophys. Res.
Volume in press Issue Pages
Keywords Sea level; Tide gauge; Norwegian coast; Arctic; Atmospheric forcing; Beaufort Gyre
Abstract Inter-annual to decadal sea level variations from tide gauge records in the coastal zones of the Norwegian and Siberian Seas are examined for the period 1950-2010 using a combination of hydrographic observations, wind data, and theory. We identify two large areas of highly coherent sea level variability: one that includes the Norwegian, Barents, and Kara Seas, and another one that includes the Laptev, East Siberian, and Chukchi Seas. We provide evidence of a new contribution to the sea level variability along the Norwegian coast associated with the poleward propagation of sea level fluctuations along the eastern boundary of the North Atlantic. When this propagating signal is combined with the local wind we are able to explain over 70% of the variance along the Norwegian coast. The steric component explains ~61% of the sea level (corrected for the inverse barometer) variability along the Norwegian coast. The high coherency between the sea level along the Norwegian coast and that in the Barents and Kara Seas suggests that part of the Norwegian signal propagates further north into these regions. We introduce an atmospheric vorcity index that explains much of the sea level variability in the Laptev, East Siberian, and Chukchi Seas with correlations ranging from 0.73 to 0.81. In the East Siberian Sea, we identify a sea level increase of ~22 cm between 2000 and 2003, which is partly explained by the vorticity index, and a decline of ~15 cm after 2003, which we relate to the strengthening of the Beaufort Gyre.
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Call Number FCI @ refbase @ Serial 333
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Author Danabasoglu, G.; Yeager, S.G.; Bailey, D.; Behrens, E.; Bentsen, M.; Bi, D.; Biastoch, A.; Böning, C.; Bozec, A.; Canuto, V.M.; Cassou, C.; Chassignet, E.; Coward, A.C.; Danilov, S.; Diansky, N.; Drange, H.; Farneti, R.; Fernandez, E.; Fogli, P.G.; Forget, G.; Fujii, Y.; Griffies, S.M.; Gusev, A.; Heimbach, P.; Howard, A.; Jung, T.; Kelley, M.; Large, W.G.; Leboissetier, A.; Lu, J.; Madec, G.; Marsland, S.J.; Masina, S.; Navarra, A.; George Nurser, A.J.; Pirani, A.; y Mélia, D.S.; Samuels, B.L.; Scheinert, M.; Sidorenko, D.; Treguier, A.-M.; Tsujino, H.; Uotila, P.; Valcke, S.; Voldoire, A.; Wang, Q.
Title North Atlantic simulations in Coordinated Ocean-ice Reference Experiments phase II (CORE-II). Part I: Mean states Type Journal Article
Year 2014 Publication Ocean Modelling Abbreviated Journal Ocean Modelling
Volume 73 Issue Pages 76-107
Keywords Global ocean-sea-ice modelling; Ocean model comparisons; Atmospheric forcing; Experimental design; Atlantic meridional overturning circulation; North Atlantic simulations
Abstract Simulation characteristics from eighteen global ocean-sea-ice coupled models are presented with a focus on the mean Atlantic meridional overturning circulation (AMOC) and other related fields in the North Atlantic. These experiments use inter-annually varying atmospheric forcing data sets for the 60-year period from 1948 to 2007 and are performed as contributions to the second phase of the Coordinated Oceanice Reference Experiments (CORE-II). The protocol for conducting such CORE-II experiments is summarized. Despite using the same atmospheric forcing, the solutions show significant differences. As most models also differ from available observations, biases in the Labrador Sea region in upper-ocean potential temperature and salinity distributions, mixed layer depths, and sea-ice cover are identified as contributors to differences in AMOC. These differences in the solutions do not suggest an obvious grouping of the models based on their ocean model lineage, their vertical coordinate representations, or surface salinity restoring strengths. Thus, the solution differences among the models are attributed primarily to use of different subgrid scale parameterizations and parameter choices as well as to differences in vertical and horizontal grid resolutions in the ocean models. Use of a wide variety of sea-ice models with diverse snow and sea-ice albedo treatments also contributes to these differences. Based on the diagnostics considered, the majority of the models appear suitable for use in studies involving the North Atlantic, but some models require dedicated development effort.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1463-5003 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number FCI @ refbase @ Serial 471
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Author Danabasoglu, G.; Yeager, S.G.; Kim, W.M.; Behrens, E.; Bentsen, M.; Bi, D.; Biastoch, A.; Bleck, R.; Böning, C.; Bozec, A.; Canuto, V.M.; Cassou, C.; Chassignet, E.; Coward, A.C.; Danilov, S.; Diansky, N.; Drange, H.; Farneti, R.; Fernandez, E.; Fogli, P.G.; Forget, G.; Fujii, Y.; Griffies, S.M.; Gusev, A.; Heimbach, P.; Howard, A.; Ilicak, M.; Jung, T.; Karspeck, A.R.; Kelley, M.; Large, W.G.; Leboissetier, A.; Lu, J.; Madec, G.; Marsland, S.J.; Masina, S.; Navarra, A.; Nurser, A.J.G.; Pirani, A.; Romanou, A.; Salas y Mélia, D.; Samuels, B.L.; Scheinert, M.; Sidorenko, D.; Sun, S.; Treguier, A.-M.; Tsujino, H.; Uotila, P.; Valcke, S.; Voldoire, A.; Wang, Q.; Yashayaev, I.
Title North Atlantic simulations in Coordinated Ocean-ice Reference Experiments phase II (CORE-II). Part II: Inter-annual to decadal variability Type Journal Article
Year 2016 Publication Ocean Modelling Abbreviated Journal Ocean Modelling
Volume 97 Issue Pages 65-90
Keywords 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. (C) 2015 Elsevier Ltd. All rights reserved.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1463-5003 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number FCI @ refbase @ Serial 907
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Author Ilicak, M.; Drange, H.; Wang, Q.; Gerdes, R.; Aksenov, Y.; Bailey, D.; Bentsen, M.; Biastoch, A.; Bozec, A.; Böning, C.; Cassou, C.; Chassignet, E.; Coward, A.C.; Curry, B.; Danabasoglu, G.; Danilov, S.; Fernandez, E.; Fogli, P.G.; Fujii, Y.; Griffies, S.M.; Iovino, D.; Jahn, A.; Jung, T.; Large, W.G.; Lee, C.; Lique, C.; Lu, J.; Masina, S.; George Nurser, A.J.; Roth, C.; Salas y Mélia, D.; Samuels, B.L.; Spence, P.; Tsujino, H.; Valcke, S.; Voldoire, A.; Wang, X.; Yeager, S.G.
Title An assessment of the Arctic Ocean in a suite of interannual CORE-II simulations. Part III: Hydrography and fluxes Type Journal Article
Year 2016 Publication Ocean Modelling Abbreviated Journal Ocean Modelling
Volume 100 Issue Pages 141-161
Keywords Arctic Ocean; Atlantic Water; St. Anna Trough; Density currents; CORE-II atmospheric forcing
Abstract In this paper we compare the simulated Arctic Ocean in 15 global ocean–sea ice models in the framework of the Coordinated Ocean-ice Reference Experiments, phase II (CORE-II). Most of these models are the ocean and sea-ice components of the coupled climate models used in the Coupled Model Intercomparison Project Phase 5 (CMIP5) experiments. We mainly focus on the hydrography of the Arctic interior, the state of Atlantic Water layer and heat and volume transports at the gateways of the Davis Strait, the Bering Strait, the Fram Strait and the Barents Sea Opening. We found that there is a large spread in temperature in the Arctic Ocean between the models, and generally large differences compared to the observed temperature at intermediate depths. Warm bias models have a strong temperature anomaly of inflow of the Atlantic Water entering the Arctic Ocean through the Fram Strait. Another process that is not represented accurately in the CORE-II models is the formation of cold and dense water, originating on the eastern shelves. In the cold bias models, excessive cold water forms in the Barents Sea and spreads into the Arctic Ocean through the St. Anna Through. There is a large spread in the simulated mean heat and volume transports through the Fram Strait and the Barents Sea Opening. The models agree more on the decadal variability, to a large degree dictated by the common atmospheric forcing. We conclude that the CORE-II model study helps us to understand the crucial biases in the Arctic Ocean. The current coarse resolution state-of-the-art ocean models need to be improved in accurate representation of the Atlantic Water inflow into the Arctic and density currents coming from the shelves.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1463-5003 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number FCI @ refbase @ Serial 973
Permanent link to this record