The role of the Southern Ocean in sea-level change

Dr Zhang

Project leader: Dr Xuebin Zhang (CSIRO)

Staff, students and associates: Prof Xianyao Chen (OUC); Prof John Church (UNSW); Prof Mat King (UTAS); Dr Yuehua (Veronica) Li (UNSW); Dr Kewei Lyu (CSIRO); Dr Steven Phipps (UTAS); Dr Christopher Watson (UTAS); Miss Jinping Wang (Ocean University of China PhD Student); Mr Jingwei Zhang (UTAS PhD Student).

[Music plays and animation waves appear moving up from the bottom of the screen and text appears above: The Centre for Southern Hemisphere Oceans Research]

[Image shows animation waves moving up the screen and over the text and then the image changes to show Xuebin Zhang talking to the camera and text appears: Xuebin Zhang, CSHOR Project Leader, CSIRO]

Xuebin Zhang: This project is going to address some scientific questions related to the sea level change such as the ocean heat uptake and redistribution in the Southern Ocean, and the contribution of the Antarctic ice sheet to the sea level change

[Image changes to show a view looking over the deck of a ship at an ice shelf in the ocean and then the image changes to show a view looking down into the water from the deck of a ship]

and regional distribution of sea level and associated underlying dynamic process in the Southern Ocean.

[Image changes to show a graph displaying sea level change with a heading “Global mean sea level anomalies” and then the image changes to show Xuebin talking to the camera]

Oh yeah, it’s a very important question to understand the sea level rise because in the past like two or three decades the research community already made very good progress in understanding and project in sea level changes but a significant gap still exists and the decision maker and the end user, they want much better information than what we can deliver right now.

[Image changes to show a sunset view looking out over the ocean and then the image changes to show a view looking over the bow of a ship at the ocean]

The Southern Ocean is one of the few key areas where the heat is up, particularly in the ocean, and secondly warming in the Southern Ocean is critical for the dynamic response of the Antarctic ice sheet.

[Image changes to show Xuebin talking to the camera]

I hope through this project we can achieve better understanding and the projecting of the sea level rise, so this information can be used for better mitigation and habitation planning for sea level rise.

[Music plays and the image changes to show animation waves across the bottom of the screen and Qingdao National Laboratory for Marine Science and Technology, CSIRO, UNSW and University of Tasmania logos appear]

Dr Xuebin Zhang introduces the Southern Ocean sea level change project

Latest news

CSHOR Science Seminar Project Presentation (PDF), July 2020

Sea-level rise began accelerating in the 1960s

August 2019

ABC Science talked with CSHOR project leader, Dr Xeubin Zhang, about the accelerating rate of modern global sea-level rise (link).

Curious Climate: will rising seas change our coastline?

August 2019

Dr Xuebin Zhang was interviewed by Joel Rheinberger on ABC radio about future sea-level rise in Tasmania (link).

Prof Jonathan Gregory visits CSHOR Hobart

Prof Jonathan Gregory from the University of Reading, UK visited CSHOR on 11-15 February. He presented a public seminar titled, ‘Dependence of climate sensitivity to CO2 on patterns of SST variation’ and met with the CSHOR sea level project team to discuss topics of overlapping research interest, i.e., ocean heat uptake and redistribution in the Southern Ocean, ocean/climate sensitivity experiments, and ocean gyre circulation. Dr Gregory and the CSHOR team also identified opportunities for future collaboration.

From left to right, Dr Xuebin Zhang, Prof Jonathan Gregory, Prof John Church, Dr Kewei Lyu and Ms Jinping Wang. CSHOR office February 2019

Prof Gregory is a well-known climate scientist, working on mechanisms of global and large-scale change in climate and sea level on multidecadal and longer timescales. He is one of three recipients of the prestigious BBVA Foundation Frontiers of Knowledge Award in the Climate Change category for their significant contribution to detecting, understanding and projecting anthropogenic sea-level rise (

Project objectives

Sea-level rise is an important climate change research topic. Global mean sea level (GMSL) has been rising according to tide gauge and satellite altimetry observations, and is projected to continue to rise, with a likely range between 0.28 m and 0.98 m by 2100. A larger rise could occur if there is a significantly larger contribution from changes in Antarctic dynamics. Over 100 million people live within a metre of current high tide mark, thus are highly likely to be affected by sea-level rise. Several processes can affect GMSL, including ocean thermal expansion, mass loss of glaciers and ice caps, the Antarctic Ice Sheet and the Greenland Ice Sheet, and changes in the land-water storage.

The Southern Ocean is a key area for improving projections of ocean heat content and sea-level change because: it is one of the key areas where heat enters the ocean, resulting in heat storage in the upper ocean and in the abyssal layers, and contributing to ocean thermal expansion; and a warming ocean is critical to the dynamic response of the Antarctic ice sheet.

Key objectives of the project are to:

  1. Quantify the amount of heat entering the Southern Ocean and associated sea-level change.
  2. Separate the impact of wind-induced vs Antarctic freshwater-induced ocean responses, and natural versus anthropogenic forcing in sea level and ocean dynamics in the SO;
  3. Examine the robustness of the dipole structure of sea-level change (centred at ~50oS) in coarse resolution models to the impacts of meso-scale eddies by comparing coarse-resolution and eddy-resolving model results, and analyse whether there are distinct responses to strengthening vs shifting of westerly winds.
  4. Refine sea-level projections based on updated observations and projections of the Antarctica Ice Sheet contribution, together with other sea level contributions.

To achieve above objectives, we will use available observations, Climate Model Intercomparison Project (CMIP) models, and an eddy-resolving (1/10o) global ocean model. For the projection of Ice Sheet contribution, we will use either stand-alone or coupled ice sheet modelling from the Ice Sheet Model Intercomparison for CMIP6.


Albrecht, F., O. Pizarro, A. Montecinos and X. Zhang (2019). Understanding Sea Level Change in the South Pacific during the late 20th and early 21st Century. Journal of Geophysical Research: Oceans, 124.

Carson, M., Lyu, K., Richter, K., Becker, M., Domingues, C. M., Han, W., & Zanna, L. (2019). Climate Model Uncertainty and Trend Detection in Regional Sea Level Projections: A Review. Surveys in Geophysics.

Chen, X. Y., Zhang, X. B., Church, J. A., Watson, C. S., King, M. A., Monselesan, D., Legrésy, B., & Harig, C. (2017). The increasing rate of global mean sea-level rise during 1993-2014. Nature Climate Change, 7(7), 492-497.

Gregory, J., et al. (2019). Concepts and Terminology for Sea Level: Mean, Variability and Change, Both Local and Global. Surveys in Geophysics.

Grose, M., S. Narsey, F. Delage, A. Dowdy, M. Bador, G. Boschat, C. Chung, J. Kajtar, S. Rauniyar, M. Freund, K. Lyu, H. Rashid, X. Zhang, S. Wales, C. Trenham, N. Holbrook, T. Cowan, L. Alexander, J. Arblaster and S. Power (2020). Insights from CMIP6 for Australia’s future climate. Earth’s Future, 8, e2019EF001469.

Han, W., Stammer, D., Thompson, P., Ezer, T., Palanisamy, H., Zhang, X., . . . Yuan, D. (2019). Impacts of Basin-Scale Climate Modes on Coastal Sea Level: a Review. Surveys in Geophysics.

Hayashida, H., R.J. Matear, P. G. Strutton and X. Zhang (2020). Insights into projected changes in marine heatwaves from a high-resolution ocean circulation model. Nature Communications, 11, 4352. .

Irving, D., W. Hobbs, J. Church, and J. Zika (2020). A Mass and Energy Conservation Analysis of Drift in the CMIP6 Ensemble.2020. Journal of Climate, online release.

King, M. A., and C. S. Watson (2020). Antarctic Surface Mass Balance: natural variability, noise and detecting new trends. Geophysical Research Letters, 47, e2020GL087493.

Li, Z., N. J. Holbrook, X. Zhang, E. C. J. Oliver, and E. A. Cougnon (2020). Remote Forcing of Tasman Sea Marine Heatwaves. Journal of Climate, 33(12), 5337–5354.

Lyu, K., X. Zhang, J. A. Church and Q. Wu (2020). Processes responsible for the Southern Hemisphere ocean heat uptake and redistribution under anthropogenic warming, Journal of Climate, 33(9), 3787-3807.

Lyu, K., X. Zhang, and J. A. Church (2020). Regional Dynamic Sea Level Simulated in the CMIP5 and CMIP6 Models: Mean Biases, Future Projections, and Their Linkages. Journal of Climate, 33(15), 6377–6398.

Meyssignac,  Benoit, Tim Boyer, Zhongxiang Zhao, Maria Z Hakuba, Felix W Landerer, Detlef Stammer, Armin Köhl, Seiji Kato, Tristan L’Ecuyer, Michael Ablain, John Patrick Abraham, Alejandro Blazquez, Anny Cazenave, John A Church, Rebecca Cowley, Lijing Cheng, Catia Domingues, Donata Giglio, Viktor Gouretski, Masayoshi Ishii, Gregory C Johnson, Rachel E Killick, David Legler, William Llovel, John Lyman, Matthew Dudley Palmer, Steve Piotrowicz, Sarah Purkey, Dean Roemmich, Rémy Roca, Abhishek Savita, Karina von Schuckmann, Sabrina Speich, Graeme Stephens, Gongjie G Wang, Susan Elisabeth Wijffels, Nathalie Zilberman (2019). Measuring Global Ocean Heat Content to estimate the Earth Energy Imbalance. Frontiers in Marine Science, 6(432).

Ponte, R. M., Carson, M., Cirano, M., Domingues, C. M., Jevrejeva, S., Marcos, M., . . . Zhang, X. (2019). Towards Comprehensive Observing and Modeling Systems for Monitoring and Predicting Regional to Coastal Sea Level. Frontiers in Marine Science, 6(437).

Richter, K., Benoit, M., Aimée, B. A. S., Angélique, M., John, A. C., Xavier, F., . . . Nicolas, C. (2020). Detecting a forced signal in satellite-era sea-level change. Environmental Research Letters.

Stammer , D., van de Wal, R. S. W., Nicholls, R. J., Church, J. A., Le Cozannet, G., Lowe, J. A., et al. (2019). Framework for high‐end estimates of sea level rise for stakeholder applications. Earth’s Future, 7, 923–938

Todd, A., L. Zanna, M. Couldrey, J. Gregory, Q. Wu, J. Church, R. Farneti, R. Navarro-Labastida, K. Lyu, O. Saenko, D.Yang and X. Zhang (2020). Ocean-only FAFMIP: understanding regional patterns of ocean heat content and dynamic sea level change. Journal of Advances in Modelling Earth Systems, 12(8).

Van de Wal, R.S.W., X. Zhang, S. Minobe, S. Jevrejeva, R.E.M. Riva, C. Little, K. Richter and M. Palmer (2019). Uncertainties in Long‑Term Twenty‑First Century Process‑Based Coastal Sea‑Level Projections. Surveys in Geophysics, 40, 1655-1671.

Wu, Q., X. Zhang, J. A. Church, and J. Hu (2019). ENSO-related Global Ocean Heat Content Variations, Journal of Climate, 32, 45-68.