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51. Evaluation of ocean carbon cycle models with data-based metrics

Author

Matsumoto, K., Sarmiento, J.L., Key, R.M., Aumont, O., Bullister, J.L., Caldeira, K., Campin, J-M., Donay, S.C., Drange, H., Dutay, J-C., Follows, M., Gao, Y., Gnanadesikan, A., Gruber, N., Ishida, A., Joos, F., Lindsay, K., Maier-Reimer, E., Marshall, J.C., Matear, R.J., Monfray, P., Mouchet, A., Najjar, R., Plattner, G-K., Schlitzer, R., Slater, R., Swathi, P.S., Totterdell, I.J., Weirig, M-F., Yamanaka, Y., Yool, A., Orr, J.C., Matsumoto, K., Sarmiento, J.L., Key, R.M., Aumont, O., Bullister, J.L., Caldeira, K., Campin, J-M., Donay, S.C., Drange, H., Dutay, J-C., Follows, M., Gao, Y., Gnanadesikan, A., Gruber, N., Ishida, A., Joos, F., Lindsay, K., Maier-Reimer, E., Marshall, J.C., Matear, R.J., Monfray, P., Mouchet, A., Najjar, R., Plattner, G-K., Schlitzer, R., Slater, R., Swathi, P.S., Totterdell, I.J., Weirig, M-F., Yamanaka, Y., Yool, A., and Orr, J.C.

Abstract

New radiocarbon and chlorofluorocarbon-11 data from the World Ocean Circulation Experiment are used to assess a suite of 19 ocean carbon cycle models. We use the distributions and inventories of these tracers as quantitative metrics of model skill and find that only about a quarter of the suite is consistent with the new data-based metrics. This should serve as a warning bell to the larger community that not all is well with current generation of ocean carbon cycle models. At the same time, this highlights the danger in simply using the available models to represent the state-of-the-art modeling without considering the credibility of each model.

Published
2004

52. Evaluating global ocean carbon models: the importance of realistic physics

Author

Doney, S. C., Lindsay, K., Caldeira, K., Campin, J. M., Drange, H., Dutay, J. C., Follows, M., Gao, Y., Gnanadesikan, A., Gruber, N., Ishida, A., Joos, F., Madec, G., Maier-Reimer, E., Marshall, J. C., Matear, R. J., Monfray, P., Mouchet, A., Najjar, R., Orr, J. C., Plattner, G. K., Sarmiento, J., Schlitzer, Reiner, Slater, R., Totterdell, I. J., Weirig, M. F., Yamanaka, Y., Yool, A., Doney, S. C., Lindsay, K., Caldeira, K., Campin, J. M., Drange, H., Dutay, J. C., Follows, M., Gao, Y., Gnanadesikan, A., Gruber, N., Ishida, A., Joos, F., Madec, G., Maier-Reimer, E., Marshall, J. C., Matear, R. J., Monfray, P., Mouchet, A., Najjar, R., Orr, J. C., Plattner, G. K., Sarmiento, J., Schlitzer, Reiner, Slater, R., Totterdell, I. J., Weirig, M. F., Yamanaka, Y., and Yool, A.

Abstract

A suite of standard ocean hydrographic and circulation metrics are applied to the equilibrium physical solutions from thirteen global carbon models participating in phase 2 of the Ocean Carbon-cycle Model Intercomparison Project (OCMIP-2). Model-data comparisons are presented for sea surface temperature and salinity, seasonal mixed layer depth, meridional heat and freshwater transport, 3-D hydrographic fields, and meridional overturning. Considerable variation exists among the OCMIP-2 simulations, with some of the solutions falling noticeably outside available observational constraints. For some cases, model-model and model-data differences can be related to variations in surface forcing, sub-grid scale parameterizations, and model architecture. These errors in the physical metrics point to significant problems in the underlying model representations of ocean transport and dynamics, problems that directly propagate into the OCMIP predicted ocean tracer and carbon cycle variables (e.g., air-sea CO2 flux; chlorofluorocarbon and anthropogenic CO2 uptake; export production). The substantial model-model ranges in OCMIP-2 biogeochemical fields (±25-40%), therefore, likely overestimate the uncertainties in ocean carbon cycle dynamics due to large-scale physical circulation.

Published
2004

53. Decadal Climate Variability, Predictability and Prediction: Opportunities and Challenges

Author

Hurrell, J.W., primary, Latif, M., additional, Visbeck, M., additional, Delworth, T.L., additional, Danabasoglu, G., additional, Dommenget, D., additional, Drange, H., additional, Drinkwater, K., additional, Griffies, S., additional, Hazeleger, W., additional, Holbrook, N.J., additional, Kirtman, B., additional, Keenlyside, N., additional, Marotzke, J., additional, Murphy, J., additional, Meehl, G. A., additional, Palmer, T., additional, Pohlmann, H., additional, Rosati, T., additional, Seager, R., additional, Smith, D., additional, Sutton, R., additional, Timmermann, A., additional, Trenberth, K. E., additional, and Tribbia, J., additional

Published
2010
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54. Evaluation of ocean model ventilation with CFC-11: comparison of 13 global ocean models

Author

Dutay, J-C., Bullister, J.L., Doney, S.C., Orr, J.C., Najjar, R., Caldeira, K., Campin, J-M., Drange, H., Follows, M., Gao, Y., Gruber, N., Hecht, M.W., Ishida, A., Joos, F., Lindsay, K., Madec, G., Maier-Reimer, E., Marshall, J.C., Matear, R.J., Monfray, P., Mouchet, A., Plattner, G-K., Sarmiento, J., Schlitzer, R., Slater, R., Totterdell, I.J., Weirig, M-F., Yamanaka, Y., Yool, A., Dutay, J-C., Bullister, J.L., Doney, S.C., Orr, J.C., Najjar, R., Caldeira, K., Campin, J-M., Drange, H., Follows, M., Gao, Y., Gruber, N., Hecht, M.W., Ishida, A., Joos, F., Lindsay, K., Madec, G., Maier-Reimer, E., Marshall, J.C., Matear, R.J., Monfray, P., Mouchet, A., Plattner, G-K., Sarmiento, J., Schlitzer, R., Slater, R., Totterdell, I.J., Weirig, M-F., Yamanaka, Y., and Yool, A.

Abstract

We compared the 13 models participating in the Ocean Carbon Model Intercomparison Project (OCMIP) with regards to their skill in matching observed distributions of CFC-11. This analysis characterizes the abilities of these models to ventilate the ocean on timescales relevant for anthropogenic CO2 uptake. We found a large range in the modeled global inventory (±30%), mainly due to differences in ventilation from the high latitudes. In the Southern Ocean, models differ particularly in the longitudinal distribution of the CFC uptake in the intermediate water, whereas the latitudinal distribution is mainly controlled by the subgrid-scale parameterization. Models with isopycnal diffusion and eddy-induced velocity parameterization produce more realistic intermediate water ventilation. Deep and bottom water ventilation also varies substantially between the models. Models coupled to a sea-ice model systematically provide more realistic AABW formation source region; however these same models also largely overestimate AABW ventilation if no specific parameterization of brine rejection during sea-ice formation is included. In the North Pacific Ocean, all models exhibit a systematic large underestimation of the CFC uptake in the thermocline of the subtropical gyre, while no systematic difference toward the observations is found in the subpolar gyre. In the North Atlantic Ocean, the CFC uptake is globally underestimated in subsurface. In the deep ocean, all but the adjoint model, failed to produce the two recently ventilated branches observed in the North Atlantic Deep Water (NADW). Furthermore, simulated transport in the Deep Western Boundary Current (DWBC) is too sluggish in all but the isopycnal model, where it is too rapid.

Published
2002

56. Observing the ocean from space: emerging capabilities in Europe

Author

Koblinsky, C.J., Smith, N.R., Johannessen, J., Le Provost, C., Drange, H., Srokosz, M., Woodworth, P., Schlussel, P., Le Grand, P., Kerr, Y., Wingham, D., Rebhan, H., Koblinsky, C.J., Smith, N.R., Johannessen, J., Le Provost, C., Drange, H., Srokosz, M., Woodworth, P., Schlussel, P., Le Grand, P., Kerr, Y., Wingham, D., and Rebhan, H.

Published
2001

60. Evaluating global ocean carbon models: The importance of realistic physics

Author

Doney, S. C., primary, Lindsay, K., additional, Caldeira, K., additional, Campin, J.-M., additional, Drange, H., additional, Dutay, J.-C., additional, Follows, M., additional, Gao, Y., additional, Gnanadesikan, A., additional, Gruber, N., additional, Ishida, A., additional, Joos, F., additional, Madec, G., additional, Maier-Reimer, E., additional, Marshall, J. C., additional, Matear, R. J., additional, Monfray, P., additional, Mouchet, A., additional, Najjar, R., additional, Orr, J. C., additional, Plattner, G.-K., additional, Sarmiento, J., additional, Schlitzer, R., additional, Slater, R., additional, Totterdell, I. J., additional, Weirig, M.-F., additional, Yamanaka, Y., additional, and Yool, A., additional

Published
2004
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61. Evaluation of ocean carbon cycle models with data‐based metrics

Author

Matsumoto, K., primary, Sarmiento, J. L., additional, Key, R. M., additional, Aumont, O., additional, Bullister, J. L., additional, Caldeira, K., additional, Campin, J.‐M., additional, Doney, S. C., additional, Drange, H., additional, Dutay, J.‐C., additional, Follows, M., additional, Gao, Y., additional, Gnanadesikan, A., additional, Gruber, N., additional, Ishida, A., additional, Joos, F., additional, Lindsay, K., additional, Maier‐Reimer, E., additional, Marshall, J. C., additional, Matear, R. J., additional, Monfray, P., additional, Mouchet, A., additional, Najjar, R., additional, Plattner, G.‐K., additional, Schlitzer, R., additional, Slater, R., additional, Swathi, P. S., additional, Totterdell, I. J., additional, Weirig, M.‐F., additional, Yamanaka, Y., additional, Yool, A., additional, and Orr, J. C., additional

Published
2004
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64. The Impacts of the Oceans on Climate Change.

Author

Lewis-Brown, E., Reid, P.C., Andersson, A., Arthurton, R., Bates, N., Barange, M., Bathmann, U., Beaugrand, G., Berger, W., Bindoff, N., Cattle, H., Chisholm, P., Church, J., de Gusmao, D., Drange, H., Dye, S., Edwards, M., Fischer, A., Flueckiger, J., and Furevik, T.

Published
2008
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71. The Norwegian Earth System Model, NorESM1-M — Part 2: Climate response and scenario projections.

Author

Iversen, T., Bentsen, M., Bethke, I., Debernard, J. B., Kirkevåg, A., Seland, Ø., Drange, H., Kristjánsson, J. E., Medhaug, I., Sand, M., and Seierstad, I. A.

Subjects
ATMOSPHERIC models, MATHEMATICAL models of atmospheric circulation, MODELS & modelmaking, CLIMATE change, METEOROLOGICAL precipitation, RADIATIVE forcing, CLIMATOLOGY
Abstract

The article presents a study that demonstrates the usefulness of the Norwegian Climate Center's Earth System Model (NorESM1-M) in the coupled model intercomparison project phase 5 (CMIP5). It outlines the role of the model in providing complementary results to the evaluation of possible man made climate change. It also demonstrates the effectiveness of the model in accurately depicting the changes in the atmospheric water cycle in precipitation events.

Published
2012
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72. The Norwegian Earth System Model, NorESM1-M — Part 1: Description and basic evaluation.

Author

Bentsen, M., Bethke, I., Debernard, J. B., Iversen, T., Kirkevåg, A., Seland, Ø., Drange, H., Roelandt, C., Seierstad, I. A., Hoose, C., and Kristjánsson, J. E.

Subjects
ATMOSPHERIC models, MATHEMATICAL models of atmospheric circulation, MODELS & modelmaking, CLIMATOLOGY
Abstract

The article presents a study that examines the capabilities of the Norwegian Climate Center's Earth System Model (NorESM1-M). It states that the model was based on the Community Climate System Model version 4 (CCSM4) of the University Corporation for Atmospheric 5 Research, and it provides advanced chemistry-aerosol-cloud-radiation interaction schemes. It also provides further analysis of the performance of the model along with climate response and scenario projections.

Published
2012
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74. Sequestration of CO2 in the deep ocean by shallow injection.

Author

Haugan, P.M. and Drange, H.

Subjects
*OCEANOGRAPHY
Abstract

Comments on the proposal by Marchetti, to separate CO2 from flue gases and inject it into the oceans as a method of alleviating the increasing atmospheric concentrations of carbon dioxide. Arguments against studies that have emphasized the need to inject the gas at great depths or in sinking currents to avoid rapid outgassing to the atmosphere; Suggestion regarding the coast of Norway; Need to evaluate such measures on marine life.

Published
1992
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75. Evaluating global ocean carbon models: The importance of realistic physics

Author

Doney, S. C., Lindsay, K., Caldeira, K., Campin, J.-M., Drange, H., Dutay, J.-C., Follows, M., Gao, Y., Gnanadesikan, A., Gruber, N., Ishida, A., Joos, F., Madec, G., Maier-Reimer, E., Marshall, J. C., Matear, R. J., Monfray, P., Mouchet, A., Najjar, R., Orr, J. C., Plattner, G.-K., Sarmiento, J., Schlitzer, R., Slater, R., Totterdell, I. J., Weirig, M.-F., Yamanaka, Y., and Yool, A.

Subjects
13. Climate action, 530 Physics, 14. Life underwater
Abstract

A suite of standard ocean hydrographic and circulation metrics are applied to the equilibrium physical solutions from 13 global carbon models participating in phase 2 of the Ocean Carbon-cycle Model Intercomparison Project (OCMIP-2). Model-data comparisons are presented for sea surface temperature and salinity, seasonal mixed layer depth, meridional heat and freshwater transport, 3-D hydrographic fields, and meridional overturning. Considerable variation exists among the OCMIP-2 simulations, with some of the solutions falling noticeably outside available observational constraints. For some cases, model-model and model-data differences can be related to variations in surface forcing, subgrid-scale parameterizations, and model architecture. These errors in the physical metrics point to significant problems in the underlying model representations of ocean transport and dynamics, problems that directly affect the OCMIP predicted ocean tracer and carbon cycle variables (e.g., air-sea CO2 flux, chlorofluorocarbon and anthropogenic CO2 uptake, and export production). A substantial fraction of the large model-model ranges in OCMIP-2 biogeochemical fields (±25–40%) represents the propagation of known errors in model physics. Therefore the model-model spread likely overstates the uncertainty in our current understanding of the ocean carbon system, particularly for transport-dominated fields such as the historical uptake of anthropogenic CO2. A full error assessment, however, would need to account for additional sources of uncertainty such as more complex biological-chemical-physical interactions, biases arising from poorly resolved or neglected physical processes, and climate change.

76. GOCINA – Geoid and Ocean Circulation in the North Atlantic

Author

Per Knudsen, Ole Baltazar Andersen, René Forsberg, Henning Pontoppidan Föh, Arne Vestergaard Olesen, Vest, A. L., Solheim, D., Omang, O. D., Hipkin, R., Hunegnaw, A., Haines, K., Bingham, R., Drecourt, J. P., Johannessen, J. A., Drange, H., Siegismund, F., Hernandez, F., Larnicol, G., Rio, M. H., and Schaeffer, P.

77. Evaluation of ocean carbon cycle models with data-based metrics

Author

Matsumoto, K., Sarmiento, J. L., Key, R. M., Aumont, O., Bullister, J. L., Caldeira, K., Campin, J.-M., Doney, S. C., Drange, H., Dutay, J.-C., Follows, M., Gao, Y., Gnanadesikan, A., Gruber, N., Ishida, A., Joos, F., Lindsay, K., Maier-Reimer, E., Marshall, J. C., Matear, R. J., Monfray, P., Mouchet, A., Najjar, R., Plattner, G.-K., Schlitzer, R., Slater, R., Swathi, P. S., Totterdell, I. J., Weirig, M.-F., Yamanaka, Y., Yool, A., and Orr, J. C.

Subjects
13. Climate action, 530 Physics, 14. Life underwater
Abstract

New radiocarbon and chlorofluorocarbon-11 data from the World Ocean Circulation Experiment are used to assess a suite of 19 ocean carbon cycle models. We use the distributions and inventories of these tracers as quantitative metrics of model skill and find that only about a quarter of the suite is consistent with the new data-based metrics. This should serve as a warning bell to the larger community that not all is well with current generation of ocean carbon cycle models. At the same time, this highlights the danger in simply using the available models to represent the state-of-the-art modeling without considering the credibility of each model.

80. Evaluation of ocean model ventilation with CFC-11: comparison of 13 global ocean models

Author

Dutay, J.-C., Bullister, J.L., Doney, S.C., Orr, J.C., Najjar, R., Caldeira, K., Campin, J.-M., Drange, H., Follows, M., Gao, Y., Gruber, N., Hecht, M.W., Ishida, A., Joos, F., Lindsay, K., Madec, G., Maier-Reimer, E., Marshall, J.C., Matear, R.J., Monfray, P., Mouchet, A., Plattner, G.-K., Sarmiento, J., Schlitzer, R., Slater, R., Totterdell, I.J., Weirig, M.-F., Yamanaka, Y., and Yool, A.

Subjects
13. Climate action, 530 Physics, 14. Life underwater
Abstract

We compared the 13 models participating in the Ocean Carbon Model Intercomparison Project (OCMIP) with regards to their skill in matching observed distributions of CFC-11. This analysis characterizes the abilities of these models to ventilate the ocean on timescales relevant for anthropogenic CO2 uptake. We found a large range in the modeled global inventory (±30%), mainly due to differences in ventilation from the high latitudes. In the Southern Ocean, models differ particularly in the longitudinal distribution of the CFC uptake in the intermediate water, whereas the latitudinal distribution is mainly controlled by the subgrid-scale parameterization. Models with isopycnal diffusion and eddy-induced velocity parameterization produce more realistic intermediate water ventilation. Deep and bottom water ventilation also varies substantially between the models. Models coupled to a sea-ice model systematically provide more realistic AABW formation source region; however these same models also largely overestimate AABW ventilation if no specific parameterization of brine rejection during sea-ice formation is included. In the North Pacific Ocean, all models exhibit a systematic large underestimation of the CFC uptake in the thermocline of the subtropical gyre, while no systematic difference toward the observations is found in the subpolar gyre. In the North Atlantic Ocean, the CFC uptake is globally underestimated in subsurface. In the deep ocean, all but the adjoint model, failed to produce the two recently ventilated branches observed in the North Atlantic Deep Water (NADW). Furthermore, simulated transport in the Deep Western Boundary Current (DWBC) is too sluggish in all but the isopycnal model, where it is too rapid.

81. An assessment of Southern Ocean water masses and sea ice during 1988–2007 in a suite of interannual CORE-II simulations

Author

Claus W. Böning, Simon J. Marsland, Lavinia Patara, Riccardo Farneti, Maxwell Kelley, A. M. Howard, David A. Bailey, Hiroyuki Tsujino, Jianhua Lu, Helge Drange, Matthew C. Long, Vittorio Canuto, Mats Bentsen, Nikolay Diansky, Stephen M. Griffies, Bonita L. Samuels, Anatoly Gusev, Erik Behrens, A. J. George Nurser, Qiang Wang, Dmitry Sidorenko, Alexandra Bozec, Eric P. Chassignet, Arne Biastoch, Gokhan Danabasoglu, Sergey Danilov, Paul Spence, Antonio Navarra, Simona Masina, Pier Giuseppe Fogli, Petteri Uotila, Mehmet Ilicak, Thomas Jung, Akhilesh Mishra, Daohua Bi, Stephanie M. Downes, Anthony Leboissetier, William G. Large, Stephen Yeager, Downes SM, Farneti R, Uotila P, Griffies SM, Marsland SJ, Bailey D, Behrens E, Bentsen M, Bi DH, Biastoch A, Boning C, Bozec A, Canuto VM, Chassignet E, Danabasoglu G, Danilov S, Diansky N, Drange H, Fogli PG, Gusev A, Howard A, Ilicak M, Jung T, Kelley M, Large WG, Leboissetier A, Long M, Lu JH, Masina S, Mishra A, Navarra A, Nurser AJG, Patara L, Samuels BL, Sidorenko D, Spence P, Tsujino H, Wang Q, and Yeager SG

Subjects
Atmospheric Science, geography, Ocean observations, geography.geographical_feature_category, Mixed layer, Antarctic sea ice, Geotechnical Engineering and Engineering Geology, Oceanography, Southern Ocean, CORE-II experiments, Water masses, Sea ice, Ocean dynamics, Sea ice thickness, Computer Science (miscellaneous), Sea ice, Environmental science, Thermohaline circulation, Ocean heat content
Abstract

We characterise the representation of the Southern Ocean water mass structure and sea ice within a suite of 15 global ocean-ice models run with the Coordinated Ocean-ice Reference Experiment Phase II (CORE-II) protocol. The main focus is the representation of the present (1988-2007) mode and intermediate waters, thus framing an analysis of winter and summer mixed layer depths; temperature, salinity, and potential vorticity structure; and temporal variability of sea ice distributions. We also consider the interannual variability over the same 20 year period. Comparisons are made between models as well as to observation-based analyses where available. The CORE-II models exhibit several biases relative to Southern Ocean observations, including an underestimation of the model mean mixed layer depths of mode and intermediate water masses in March (associated with greater ocean surface heat gain), and an overestimation in September (associated with greater high latitude ocean heat loss and a more northward winter sea-ice extent). In addition, the models have cold and fresh/warm and salty water column biases centred near 50 degrees S. Over the 1933-2007 period, the CORE-II models consistently simulate spatially variable trends in sea-ice concentration, surface freshwater fluxes, mixed layer depths, and 200-700 in ocean heat content. In particular, sea-ice coverage around most of the Antarctic continental shelf is reduced, leading to a cooling and freshening of the near surface waters. The shoaling of the mixed layer is associated with increased surface buoyancy gain, except in the Pacific where sea ice is also influential. The models are in disagreement, despite the common CORE-II atmospheric state, in their spatial pattern of the 20-year trends in the mixed layer depth and sea-ice. (C) 2015 Elsevier Ltd. All rights reserved

Published
2015

82. An assessment of Antarctic Circumpolar Current and Southern Ocean meridional overturning circulation during 1958–2007 in a suite of interannual CORE-II simulations

Author

Simon J. Marsland, Anthony Leboissetier, Steve G. Yeager, Antonio Navarra, Lavinia Patara, Vittorio Canuto, Simona Masina, Daohua Bi, Pier Giuseppe Fogli, Matthew C. Long, Mehmet Ilicak, Stephanie M. Downes, Eric P. Chassignet, Mats Bentsen, A. J. George Nurser, William G. Large, Riccardo Farneti, Petteri Uotila, Sergey Danilov, Anatoly Gusev, Maxwell Kelley, Akhilesh Mishra, Claus W. Böning, Robert Hallberg, Hiroyuki Tsujino, Jianhua Lu, Dmitry Sidorenko, Alexandra Bozec, Gokhan Danabasoglu, Thomas Jung, A. M. Howard, Nikolay Diansky, Stephen M. Griffies, Helge Drange, Bonita L. Samuels, Erik Behrens, Qiang Wang, Arne Biastoch, Farneti R, Downes SM, Griffies SM, Marsland SJ, Behrens E, Bentsen M, Bi DH, Biastoch A, Boning C, Bozec A, Canuto VM, Chassignet E, Danabasoglu G, Danilov S, Diansky N, Drange H, Fogli PG, Gusev A, Hallberg RW, Howard A, Ilicak M, Jung T, Kelley M, Large WG, Leboissetier A, Long M, Lu JH, Masina S, Mishra A, Navarra A, Nurser AJG, Patara L, Samuels BL, Sidorenko D, Tsujino H, Uotila P, Wang Q, and Yeager SG

Subjects
Atmospheric Science, Momentum (technical analysis), Isopycnal, Buoyancy, 010504 meteorology & atmospheric sciences, 010505 oceanography, Advection, Mode (statistics), Mesoscale meteorology, Forcing (mathematics), engineering.material, Geotechnical Engineering and Engineering Geology, Oceanography, 01 natural sciences, 13. Climate action, Climatology, Computer Science (miscellaneous), engineering, Thermohaline circulation, 14. Life underwater, Global ocean–sea ice modeling, Model comparisons, Southern Ocean meridional overturning circulation, Antarctic Circumpolar Current, Southern Ocean dynamics, Geology, 0105 earth and related environmental sciences
Abstract

In the framework of the second phase of the Coordinated Ocean-ice Reference Experiments (CORE-II), we present an analysis of the representation of the Antarctic Circumpolar Current (ACC) and Southern Ocean meridional overturning circulation (MOC) in a suite of seventeen global ocean-sea ice models. We focus on the mean, variability and trends of both the ACC and MOC over the 1958-2007 period, and discuss their relationship with the surface forcing. We aim to quantify the degree of eddy saturation and eddy compensation in the models participating in CORE-II, and compare our results with available observations, previous fineresolution numerical studies and theoretical constraints. Most models show weak ACC transport sensitivity to changes in forcing during the past five decades, and they can be considered to be in an eddy saturated regime. Larger contrasts arise when considering MOC trends, with a majority of models exhibiting significant strengthening of the MOC during the late 20th and early 21st century. Only a few models show a relatively small sensitivity to forcing changes, responding with an intensified eddy-induced circulation that provides some degree of eddy compensation, while still showing considerable decadal trends. Both ACC and MOC interannual variabilities are largely controlled by the Southern Annular Mode (SAM). Based on these results, models are clustered into two groups. Models with constant or two-dimensional (horizontal) specification of the eddy-induced advection coefficient K show larger ocean interior decadal trends, larger ACC transport decadal trends and no eddy compensation in the MOC. Eddy-permitting models or models with a threedimensional time varying K show smaller changes in isopycnal slopes and associated ACC trends, and partial eddy compensation. As previously argued, a constant in time or space lc is responsible for a poor representation of mesoscale eddy effects and cannot properly simulate the sensitivity of the ACC and MOC to changing surface forcing. Evidence is given for a larger sensitivity of the MOC as compared to the ACC transport, even when approaching eddy saturation. Future process studies designed for disentangling the role of momentum and buoyancy forcing in driving the ACC and MOC are proposed. (C) 2015 Elsevier Ltd. All rights reserved.

Published
2015

83. North Atlantic simulations in Coordinated Ocean-ice Reference Experiments phase II (CORE-II). Part II: Inter-annual to decadal variability

Author

Patrick Heimbach, Aurore Voldoire, Anatoly Gusev, Alicia Karspeck, Eric P. Chassignet, Rainer Bleck, Dmitry Sidorenko, Alexandra Bozec, David Salas y Mélia, Anastasia Romanou, Who M. Kim, Gael Forget, Daohua Bi, Vittorio Canuto, Simon J. Marsland, Gokhan Danabasoglu, Simona Masina, Hiroyuki Tsujino, Stephen M. Griffies, Sophie Valcke, Jianhua Lu, Mats Bentsen, Claus W. Böning, Pier Giuseppe Fogli, Gurvan Madec, Anthony Leboissetier, Mehmet Ilicak, Anna Pirani, Thomas Jung, Igor Yashayaev, Andrew C. Coward, Maxwell Kelley, Shan Sun, Yosuke Fujii, A. J. George Nurser, Petteri Uotila, Sergey Danilov, Elodie Fernandez, Steve G. Yeager, Christophe Cassou, Nikolay Diansky, A. M. Howard, William G. Large, Helge Drange, Anne-Marie Tréguier, Bonita L. Samuels, Erik Behrens, Qiang Wang, Arne Biastoch, Riccardo Farneti, Markus Scheinert, Antonio Navarra, National Center for Atmospheric Research [Boulder] (NCAR), Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Uni Research Climate, Uni Research Ltd, Centre for Australian Weather and Climate Research (CAWCR), NASA Goddard Institute for Space Studies (GISS), NASA Goddard Space Flight Center (GSFC), Center for Ocean-Atmospheric Prediction Studies (COAPS), Florida State University [Tallahassee] (FSU), Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), National Oceanography Centre (NOC), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Institute of Numerical Mathematics [Moscou] (INM-RAS), Russian Academy of Sciences [Moscow] (RAS), University of Bergen (UiB), Abdus Salam International Centre for Theoretical Physics [Trieste] (ICTP), Centro Euro-Mediterraneo per i Cambiamenti Climatici [Bologna] (CMCC), Massachusetts Institute of Technology (MIT), Meteorological Research Institute [Tsukuba] (MRI), Japan Meteorological Agency (JMA), NOAA Geophysical Fluid Dynamics Laboratory (GFDL), National Oceanic and Atmospheric Administration (NOAA), Pacific Northwest National Laboratory (PNNL), Nucleus for European Modeling of the Ocean (NEMO R&D ), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Matematica e Informatica [Perugia] (DMI), Università degli Studi di Perugia = University of Perugia (UNIPG), National Oceanography Centre [Southampton] (NOC), University of Southampton, International CLIVAR, Princeton University, Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Leibniz-Institut für Meereswissenschaften (IFM-GEOMAR), Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Biomedical Research Imaging Center [North Carolina] (BRIC), University of North Carolina [Chapel Hill] (UNC), University of North Carolina System (UNC)-University of North Carolina System (UNC), Danabasoglu G, Yeager SG, Kim WM, Behrens E, Bentsen M, Bi DH, Biastoch A, Bleck R, Boning C, Bozec A, Canuto VM, Cassou C, Chassignet E, Coward AC, Danilov S, Diansky N, Drange H, Farneti R, Fernandez E, Fogli PG, Forget G, Fujii Y, Griffies SM, Gusev A, Heimbach P, Howard A, Ilicak M, Jung T, Karspeck AR, Kelley M, Large WG, Leboissetier A, Lu JH, Madec G, Marsland SJ, Masina S, Navarra A, Nurser AJG, Pirani A, Romanou A, Melia DSY, Samuels BL, Scheinert M, Sidorenko D, Sun S, Treguier AM, Tsujino H, Uotila P, Valcke S, Voldoire A, Wang Q, Yashayaev I, CERFACS [Toulouse], Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Università degli Studi di Perugia (UNIPG), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), and CERFACS

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Mixed layer, Phase (waves), [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Oceanography, 01 natural sciences, Ocean model comparisons, Computer Science (miscellaneous), 14. Life underwater, Atmospheric forcing, Variability in the North Atlantic, 0105 earth and related environmental sciences, Inter-annual to decadal variability and mechanisms, Atlantic meridional overturning circulation variability, 010505 oceanography, Global ocean - sea-ice modelling, Geotechnical Engineering and Engineering Geology, Deep water, Ocean dynamics, Marine Sciences, Sea surface temperature, 13. Climate action, North Atlantic oscillation, Climatology, Global ocean – sea-ice modelling, Ocean model comparisons, Atmospheric forcing, Hydrography, Global ocean – sea-ice modelling, Geology
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.

Published
2016

84. North Atlantic simulations in Coordinated Ocean-ice Reference Experiments phase II (CORE-II). Part I: Mean states

Author

Hiroyuki Tsujino, Jianhua Lu, Anatoly Gusev, David A. Bailey, Simon J. Marsland, Yosuke Fujii, Elodie Fernandez, Nikolay Diansky, Claus W. Böning, Gael Forget, Helge Drange, Anne-Marie Tréguier, Andrew C. Coward, Gokhan Danabasoglu, Mats Bentsen, Eric P. Chassignet, William G. Large, Sergey Danilov, A. J. George Nurser, Christophe Cassou, Riccardo Farneti, Bonita L. Samuels, Patrick Heimbach, David Salas y Mélia, Erik Behrens, Stephen M. Griffies, Gurvan Madec, Qiang Wang, Anthony Leboissetier, Arne Biastoch, Maxwell Kelley, Vittorio Canuto, Markus Scheinert, Aurore Voldoire, A. M. Howard, Steve G. Yeager, Thomas Jung, Petteri Uotila, Simona Masina, Pier Giuseppe Fogli, Daohua Bi, Sophie Valcke, Dmitry Sidorenko, Alexandra Bozec, Antonio Navarra, Anna Pirani, National Center for Atmospheric Research [Boulder] (NCAR), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Uni Research Climate, Uni Research Ltd, Centre for Australian Weather and Climate Research (CAWCR), Leibniz-Institut für Meereswissenschaften (IFM-GEOMAR), Center for Ocean-Atmospheric Prediction Studies (COAPS), Florida State University [Tallahassee] (FSU), NASA Goddard Institute for Space Studies (GISS), NASA Goddard Space Flight Center (GSFC), Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), CERFACS, National Oceanography Centre (NOC), Massachusetts Institute of Technology (MIT), NOAA Geophysical Fluid Dynamics Laboratory (GFDL), National Oceanic and Atmospheric Administration (NOAA), Nucleus for European Modeling of the Ocean (NEMO R&D ), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Istituto Nazionale di Geofisica e Vulcanologia - Sezione di Bologna (INGV), Istituto Nazionale di Geofisica e Vulcanologia, International CLIVAR, Princeton University, Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Centre national de recherches météorologiques (CNRM), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Danabasoglu G, Yeager SG, Bailey D, Behrens E, Bentsen M, Bi D, Biastoch A, Boning C, Bozec A, Canuto VM, Cassou C, Chassignet E, Coward AC, Danilov S, Diansky N, Drange H, Farneti R, Fernandez E, Fogli PG, Forget G, Fujii Y, Griffies SM, Gusev A, Heimbach P, Howard A, Jung T, Kelley M, Large WG, Leboissetier A, Lu J, Madec G, Marsland SJ, Masina S, Navarra A, Nurser AJG, Pirani A, Melia DSY, Samuels BL, Scheinert M, Sidorenko D, Treguier AM, Tsujino H, Uotila P, Valcke S, Voldoire A, and Wangi Q

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Mixed layer, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, Atlantic meridional overturning circulation, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Oceanography, 01 natural sciences, Ocean model comparisons, Computer Science (miscellaneous), Sea ice, Potential temperature, Hindcast, 14. Life underwater, Atmospheric forcing, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, 010505 oceanography, Global ocean–sea-ice modelling, Ocean model comparisons, Atmospheric forcing, Experimental design, Atlantic meridional overturning circulation, North Atlantic simulations, Albedo, Geotechnical Engineering and Engineering Geology, Snow, Experimental design, Sea surface temperature, 13. Climate action, Meridional flow, Climatology, Environmental science, Global ocean-sea-ice modelling
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. (C) 2013 Elsevier Ltd. All rights reserved.

Published
2014

86. Sources and pathways of 90Sr in the North Atlantic-Arctic region: present day and global warming.

Author

Gao Y, Drange H, Johannessen OM, and Pettersson LH

Subjects
Arctic Regions, Atlantic Ocean, Cesium Radioisotopes analysis, Computer Simulation, Water Movements, Models, Theoretical, Radiation Monitoring statistics & numerical data, Radioactive Pollutants analysis, Strontium Radioisotopes analysis
Abstract

The spatial and temporal distributions of the anthropogenic radionuclides (137)Cs and (90)Sr, originating from nuclear bomb testing, the Sellafield reprocessing plant in the Irish Sea (UK), and from the Ob and Yenisey river discharges to the Arctic Ocean, have been simulated using the global version of the Miami Isopycnic Coordinate Ocean Model (MICOM). The physical model is forced with daily atmospheric re-analysis fields for the period of 1948-1999. Comparison of the temporal evolution of the observed and the simulated concentrations of (90)Sr has been performed in the Kara Sea. The relative contributions of the different sources on the temporal and spatial distributions of the surface (90)Sr are quantified over the simulated period. It follows that the Ob river discharge dominated the surface (90)Sr over most of the Arctic Ocean and along the eastern and western coasts of Greenland before 1960. During the period of 1980-1990, the atmospheric fallout and the Ob river discharge were equally important for the (90)Sr distribution in the Arctic Ocean. Furthermore, an attempt has been made to explore the possible dispersion of accidental released (90)Sr from the Ob and Yenisey rivers under a global warming scenario (2 x CO(2)). The difference between the present-day and the global warming scenario runs indicates that more of the released (90)Sr from the Ob and Yenisey rivers is confined to the Arctic Ocean in the global warming run, particularly in the near coastal, non-European part of the Arctic Ocean.

Published
2009
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87. Influence of the Atlantic subpolar gyre on the thermohaline circulation.

Author

Hátún H, Sandø AB, Drange H, Hansen B, and Valdimarsson H

Abstract

During the past decade, record-high salinities have been observed in the Atlantic Inflow to the Nordic Seas and the Arctic Ocean, which feeds the North Atlantic thermohaline circulation (THC). This may counteract the observed long-term increase in freshwater supply to the area and tend to stabilize the North Atlantic THC. Here we show that the salinity of the Atlantic Inflow is tightly linked to the dynamics of the North Atlantic subpolar gyre circulation. Therefore, when assessing the future of the North Atlantic THC, it is essential that the dynamics of the subpolar gyre and its influence on the salinity are taken into account.

Published
2005
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88. Simulating transport of non-Chernobyl (137)Cs and (90)Sr in the North Atlantic-Arctic region.

Author

Gao Y, Drange H, Bentsen M, and Johannessen OM

Subjects
Air Movements, Arctic Regions, Atlantic Ocean, Cesium Radioisotopes analysis, Forecasting, Greenhouse Effect, Strontium Radioisotopes analysis, Air Pollutants, Radioactive analysis, Models, Theoretical, Nuclear Warfare
Abstract

The spatial and temporal distributions of the anthropogenic radionuclides (137)Cs and (90)Sr, originating from nuclear bomb testing and the Sellafield reprocessing plants in the Irish Sea, are simulated using a global version of the Miami Isopycnic Coordinate Ocean Model (MICOM). The physical model is forced with daily atmospheric re-analysed fields for the period 1950 to present. Comparison of temporal evolution of observed and simulated concentrations of (137)Cs have been conducted for the regions east of Scotland, west of central Norway and at the entrance of the Barents Sea. It follows that the radionuclides from the Sellafield discharge reach the Barents Sea region after 4-5 years, in accordance with observations. The simulation provides a detailed distribution and evolution of the radionuclides over the integration time. For the Atlantic waters off the coast of Norway and in the southern Barents Sea, the atmospheric fallout dominates over the Sellafield release up to the mid 1960s and from the early 1990s, whereas Sellafield is the main source for the two radionuclides in the 1970s and 1980s. It is furthermore argued that model systems like the one presented here can be used for future prediction of radioactive contaminations in the Nordic Seas and the Arctic Ocean, for instance under various global warming scenarios.

Published
2004
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89. [Changes in the use of compulsory measures in Norwegian psychiatric institutions].

Author

Høyer G and Drange H

Subjects
Hospitals, Psychiatric statistics & numerical data, Humans, Mental Disorders drug therapy, Mental Disorders therapy, Norway, Patient Isolation statistics & numerical data, Psychiatric Department, Hospital statistics & numerical data, Psychiatric Department, Hospital trends, Drug Utilization trends, Hospitals, Psychiatric trends, Patient Isolation trends, Psychotropic Drugs administration & dosage, Restraint, Physical
Abstract

This paper presents the second screening concerning the use of coercive measures in Norwegian mental health institutions. The use of mechanical restraint, seclusion and forced medication was recorded during the first six months of 1989 and of 1990. We found no change in the use of coercive measures from 1989 to 1990, nor did we find any differences when the results of this screening was compared with those of the first screening carried out in 1986-88. Mechanical restraint was the most commonly used coercive measure, and a total of 9402 hours of such constraint was recorded the first six months of 1990. In many cases, a substantial part of the total amount of mechanical restraint in the different institutions at different times referred to a single patient, which created large variations in the use of coercion. No correlation was found between the use of coercion on one hand and size of ward and staff ratio on the other; factors that otherwise are believed to be of importance for use of coercion.

Published
1994

90. [Use of coercive measures in Norwegian psychiatric institutions].

Author

Høyer G and Drange H

Subjects
History, 18th Century, History, 19th Century, History, 20th Century, Hospitals, Psychiatric statistics & numerical data, Humans, Mental Disorders psychology, Norway, Protective Devices, Coercion, Hospitals, Psychiatric history, Mental Disorders therapy, Patient Isolation methods, Patient Isolation psychology, Restraint, Physical methods, Restraint, Physical psychology
Abstract

This paper addresses the use of coercive measures in Norwegian mental health care in recent years. The use of mechanical restraint and seclusion was recorded for the first six months of 1986 and 1988. During the first six months of 1988, 203 patients had been restrained mechanically for a total of 10,767 hours, while 73 patients required seclusion for a total of 3,914 hours during the same period. The results showed that there had been no increase in the total number of hours when coercion had been applied over the actual period, but a significant increase was found in the number of patients who had been subjected to coercive measures. These results are discussed in relation to the number of available beds, staff ratio and patient turnover in Norwegian mental health institutions.

Published
1991

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