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

Stephanie M. Downes; Riccardo Farneti; Petteri Uotila; Stephen M. Griffies; Simon J. Marsland; David Bailey; Erik Behrens; Mats Bentsen; Daohua Bi; Arne Biastoch; Claus Böning; Alexandra Bozec; Vittorio M. Canuto; Eric Chassignet; Gokhan Danabasoglu; Sergey Danilov; Nikolay Diansky; Helge Drange; Pier Giuseppe Fogli; Anatoly Gusev; Armando Howard; Mehmet Ilicak; Thomas Jung; Maxwell Kelley; William G. Large; Anthony Leboissetier; Matthew Long; Jianhua Lu; Simona Masina; Akhilesh Mishra; Antonio Navarra; A. J. George Nurser; Lavinia Patara; Bonita L. Samuels; Dmitry Sidorenko; Paul Spence; Hiroyuki Tsujino; Qiang Wang; Stephen G. Yeager

doi:10.1016/j.ocemod.2015.07.022

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

Stephanie M. Downes^*, Riccardo Farneti, Petteri Uotila, Stephen M. Griffies, Simon J. Marsland, David Bailey, Erik Behrens, Mats Bentsen, Daohua Bi, Arne Biastoch, Claus Böning, Alexandra Bozec, Vittorio M. Canuto, Eric Chassignet, Gokhan Danabasoglu, Sergey Danilov, Nikolay Diansky, Helge Drange, Pier Giuseppe Fogli, Anatoly GusevArmando Howard, Mehmet Ilicak, Thomas Jung, Maxwell Kelley, William G. Large, Anthony Leboissetier, Matthew Long, Jianhua Lu, Simona Masina, Akhilesh Mishra, Antonio Navarra, A. J. George Nurser, Lavinia Patara, Bonita L. Samuels, Dmitry Sidorenko, Paul Spence, Hiroyuki Tsujino, Qiang Wang, Stephen G. Yeager

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

70 Citations (Scopus)

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°S. Over the 1988-2007 period, the CORE-II models consistently simulate spatially variable trends in sea-ice concentration, surface freshwater fluxes, mixed layer depths, and 200-700 m 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.

Original language	English
Pages (from-to)	67-94
Number of pages	28
Journal	Ocean Modelling
Volume	94
DOIs	https://doi.org/10.1016/j.ocemod.2015.07.022
Publication status	Published - 1 Oct 2015
Externally published	Yes

Bibliographical note

Publisher Copyright:
© 2015 Elsevier Ltd.

Funding

The CLIVAR Ocean Model Development Panel (OMDP) is responsible for organising the Coordinated Ocean-sea ice Reference Experiments, with support from international CLIVAR and U.S. CLIVAR project offices, particularly Anna Pirani. We are grateful for the efforts of modellers who have contributed to the simulation and processing of the CORE-II experiments. S. M. Downes was supported by the ARC Centre of Excellence for Climate System Science (grant CE110001028). The ACCESS model is supported by the Australian Government Department of the Environment, the Bureau of Meteorology and CSIRO through the Australian Climate Change Science Programme. A.W.I. is a member of the Helmholtz Association of German Research Centers. Q. Wang and D. Sidorenko are funded by the Helmholtz Climate Initiative REKLIM (Regional Climate Change), a joint research project of the Helmholtz Association of German research centers (HGF) under grant: REKLIM-2009-07-16. The GEOMAR model integrations were built on developments in the DRAKKAR collaboration, were performed at the North-German Supercomputing Alliance (HLRN), and were supported by the Cluster of Excellence ‘The Future Ocean’. The BERGEN contribution is supported by the Research Council of Norway through the EarthClim ( 207711/E10 ) and NOTUR/NorStore projects, as well as the Centre for Climate Dynamics at the Bjerknes Centre for Climate Research. The CMCC contribution received funding from the Italian Ministry of Education, University, and Research and the Italian Ministry of Environment, Land, and Sea under the GEMINA project. NCAR is sponsored by the U. S. National Science Foundation (NSF). S. G. Yeager was supported by the NOAA Climate Program Office under Climate Variability and Predictability Program grant NA09OAR4310163 . We thank Carolina Dufour and Adele Morrison for their useful comments on earlier drafts, and two anonymous reviewers for their constructive comments, all of which helped improve the paper.

Funders	Funder number
ARC Centre of Excellence for Climate System Science	CE110001028
Bureau of Meteorology
Helmholtz Climate Initiative REKLIM
Italian Ministry of Environment, Land
NOTUR
NorStore
National Science Foundation
National Oceanic and Atmospheric Administration	NA09OAR4310163
Natural Environment Research Council	noc010010
National Stroke Foundation
Commonwealth Scientific and Industrial Research Organisation
Helmholtz-Gemeinschaft	REKLIM-2009-07-16
Ministero dell’Istruzione, dell’Università e della Ricerca
Department of the Environment, Australian Government
Norges Forskningsråd	207711/E10
Helmholtz Association

Keywords

CORE-II experiments
Ocean model intercomparison
Sea ice
Southern Ocean
Water masses

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Access to Document

10.1016/j.ocemod.2015.07.022

Cite this

Downes, S. M., Farneti, R., Uotila, P., Griffies, S. M., Marsland, S. J., Bailey, D., Behrens, E., Bentsen, M., Bi, D., Biastoch, A., Böning, C., Bozec, A., Canuto, V. M., Chassignet, E., Danabasoglu, G., Danilov, S., Diansky, N., Drange, H., Fogli, P. G., ... Yeager, S. G. (2015). An assessment of Southern Ocean water masses and sea ice during 1988-2007 in a suite of interannual CORE-II simulations. Ocean Modelling, 94, 67-94. https://doi.org/10.1016/j.ocemod.2015.07.022

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title = "An assessment of Southern Ocean water masses and sea ice during 1988-2007 in a suite of interannual CORE-II simulations",

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°S. Over the 1988-2007 period, the CORE-II models consistently simulate spatially variable trends in sea-ice concentration, surface freshwater fluxes, mixed layer depths, and 200-700 m 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.",

keywords = "CORE-II experiments, Ocean model intercomparison, Sea ice, Southern Ocean, Water masses",

author = "Downes, {Stephanie M.} and Riccardo Farneti and Petteri Uotila and Griffies, {Stephen M.} and Marsland, {Simon J.} and David Bailey and Erik Behrens and Mats Bentsen and Daohua Bi and Arne Biastoch and Claus B{\"o}ning and Alexandra Bozec and Canuto, {Vittorio M.} and Eric Chassignet and Gokhan Danabasoglu and Sergey Danilov and Nikolay Diansky and Helge Drange and Fogli, {Pier Giuseppe} and Anatoly Gusev and Armando Howard and Mehmet Ilicak and Thomas Jung and Maxwell Kelley and Large, {William G.} and Anthony Leboissetier and Matthew Long and Jianhua Lu and Simona Masina and Akhilesh Mishra and Antonio Navarra and {George Nurser}, {A. J.} and Lavinia Patara and Samuels, {Bonita L.} and Dmitry Sidorenko and Paul Spence and Hiroyuki Tsujino and Qiang Wang and Yeager, {Stephen G.}",

note = "Publisher Copyright: {\textcopyright} 2015 Elsevier Ltd.",

year = "2015",

month = oct,

day = "1",

doi = "10.1016/j.ocemod.2015.07.022",

language = "English",

volume = "94",

pages = "67--94",

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Downes, SM, Farneti, R, Uotila, P, Griffies, SM, Marsland, SJ, Bailey, D, Behrens, E, Bentsen, M, Bi, D, Biastoch, A, Böning, 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, J, Masina, S, Mishra, A, Navarra, A, George Nurser, AJ, Patara, L, Samuels, BL, Sidorenko, D, Spence, P, Tsujino, H, Wang, Q & Yeager, SG 2015, 'An assessment of Southern Ocean water masses and sea ice during 1988-2007 in a suite of interannual CORE-II simulations', Ocean Modelling, vol. 94, pp. 67-94. https://doi.org/10.1016/j.ocemod.2015.07.022

TY - JOUR

T1 - An assessment of Southern Ocean water masses and sea ice during 1988-2007 in a suite of interannual CORE-II simulations

AU - Downes, Stephanie M.

AU - Farneti, Riccardo

AU - Uotila, Petteri

AU - Griffies, Stephen M.

AU - Marsland, Simon J.

AU - Bailey, David

AU - Behrens, Erik

AU - Bentsen, Mats

AU - Bi, Daohua

AU - Biastoch, Arne

AU - Böning, Claus

AU - Bozec, Alexandra

AU - Canuto, Vittorio M.

AU - Chassignet, Eric

AU - Danabasoglu, Gokhan

AU - Danilov, Sergey

AU - Diansky, Nikolay

AU - Drange, Helge

AU - Fogli, Pier Giuseppe

AU - Gusev, Anatoly

AU - Howard, Armando

AU - Ilicak, Mehmet

AU - Jung, Thomas

AU - Kelley, Maxwell

AU - Large, William G.

AU - Leboissetier, Anthony

AU - Long, Matthew

AU - Lu, Jianhua

AU - Masina, Simona

AU - Mishra, Akhilesh

AU - Navarra, Antonio

AU - George Nurser, A. J.

AU - Patara, Lavinia

AU - Samuels, Bonita L.

AU - Sidorenko, Dmitry

AU - Spence, Paul

AU - Tsujino, Hiroyuki

AU - Wang, Qiang

AU - Yeager, Stephen G.

PY - 2015/10/1

Y1 - 2015/10/1

N2 - 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°S. Over the 1988-2007 period, the CORE-II models consistently simulate spatially variable trends in sea-ice concentration, surface freshwater fluxes, mixed layer depths, and 200-700 m 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.

AB - 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°S. Over the 1988-2007 period, the CORE-II models consistently simulate spatially variable trends in sea-ice concentration, surface freshwater fluxes, mixed layer depths, and 200-700 m 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.

KW - CORE-II experiments

KW - Ocean model intercomparison

KW - Sea ice

KW - Southern Ocean

KW - Water masses

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U2 - 10.1016/j.ocemod.2015.07.022

DO - 10.1016/j.ocemod.2015.07.022

M3 - Article

AN - SCOPUS:84930231422

SN - 1463-5003

VL - 94

SP - 67

EP - 94

JO - Ocean Modelling

JF - Ocean Modelling

ER -

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

Abstract

Bibliographical note

Funding

Keywords

UN SDGs

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