Southern Ocean observations and change
Project Leader: Dr Steve Rintoul
Staff and students: Dr Laura Herraiz-Borreguero (CSIRO); Dr Elizabeth Shadwick (CSIRO); Mr Saisai Hou (Ocean University of China 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 Steve Rintoul talking to the camera and text appears: Steve Rintoul, CSHOR Project Leader, CSIRO]
Steve Rintoul: My project is looking at the Southern Ocean with an emphasis on observations of the Southern Ocean and we’re targeting a few different things. One is changes in the deep ocean. We’ve found some of the strongest signals of change anywhere in the deep ocean in the waters around Antarctica and we really need to understand why. What does it mean? What are the implications of that and why is it happening?
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And one way we’ll do that is through ships, the traditional way that we have of measuring the deepest parts of the ocean, but we’ll also be deploying the first pilot arrays of something called deep Argo floats. These are profiling floats that can work through the whole ocean depth.
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Eighty percent of the Southern Hemisphere is covered by oceans and they’ve been largely unmeasured and poorly understood.
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That’s beginning to change, and we can use that new information to develop new insights into how the Southern Hemisphere oceans work and how they affect regional and global climate.
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This project will achieve two things.
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One it will allow us to better understand how and why the deep ocean is changing and two how changes in the Southern Ocean will affect the Antarctic ice sheet where the waters interact with the floating ice around the edge of Antarctica.
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Dr Steve Rintoul introduces the Southern Ocean observations and change project
The project will collect new physical and biogeochemical observations in the Southern Ocean and use them with the historical record to develop a better physical understanding of the sensitivity of circulation and water mass formation to changes in forcing.
The overall objective of the project is to quantify variability and trends in ocean circulation and water mass formation in the Australian sector of the Southern Ocean, using a combination of shipboard data, float observations and satellite data, and to identify the physical mechanisms driving change.
Specific objectives include:
- Quantify full-ocean depth changes along the SR3 repeat hydrographic section between Tasmania and Antarctica
- As part of a collaborative project with NZ and the USA, use profiling floats to obtain the first comprehensive, year-round measurements of the Ross Gyre and quantify the circulation
- Lead the design and implementation of the first international deep Argo pilot array in the Southern Ocean
- Assess the potential for warm ocean waters to reach ice shelf cavities in East Antarctica and drive enhanced basal melt, with potential focus areas including Prydz Bay and the Shackleton Ice Shelf
AMOS Uwe Radok Award (Dec. 2020)
Dr Alessandro Silvano, the lead author of the recent CSHOR paper published in Nature Geoscience, has just been awarded the Uwe Radok Award for best PhD thesis by the Australian Meteorological and Oceanographic Society. Dr Silvano completed his PhD at the Institute for Marine and Antarctic Studies (IMAS) at the University of Tasmania, and is now a Research Fellow at the University of Southampton in the UK. His PhD research at IMAS focused on the ocean-ice shelf interaction at the Totten Glacier in East Antarctica; supervised by IMAS Associate Professor Guy Williams, and CSHOR’s Drs Steve Rintoul and Beatriz Peña-Molino. Dr Silvano was employed by CSHOR on a casual appointment following completion of his PhD.
Recent climate extremes have driven unprecedented changes in the deep ocean (Nov. 2020)
A new study, led by Dr Alessandro Silvano from the University of Southampton and CSIRO and CSHOR researchers and published in the journal Nature Geoscience, documents an increase in the supply of bottom water to the deep Indian and Pacific Oceans. New measurements reveal a surprising increase in the amount of dense water sinking near Antarctica, following 50 years of decline. The study highlights the sensitivity of Antarctic Bottom Water (AABW) formation to remote forcing and shows that climate anomalies can drive episodic increases in local sea ice formation that counter the tendency for increased ice-sheet melt to reduce AABW formation.
Arroyo, M. C., E. H. Shadwick, B. Tilbrook, S. R. Rintoul, and K. Kusahara (2020). A continental shelf pump for CO2 on the Adélie Land coast, East Antarctica. Journal of Geophysical Research: Oceans, 125(10), e2020JC016302. https://doi.org/10.1029/2020JC016302.
Bestley, S., V. Andrews-Goff, E. van Wijk, S. R. Rintoul, M. C.Double and J. How (2019). New insights into prime forage grounds for thriving Western Australian humpback whales. Scientific Reports, 9, 13988. https://doi.org/10.1038/s41598-019-50497-2.
Castagno, P. V. Capozzi, G. R. DiTullio, P. Falco, G. Fusco, S. R. Rintoul, and G. Budillon (2019). Rebound of shelf water salinity in the Ross Sea. Nature Communications, 10, 1-6. https://doi.org/10.1038/s41467-019-13083-8.
Cougnon, E. A., Galton-Fenzi, B. K., Rintoul, S. R., Legrésy, B., Williams, G. D., Fraser, A. D., & Hunter, J. R. (2017). Regional Changes in Icescape Impact Shelf Circulation and Basal Melting. Geophysical Research Letters, 44(22), 11,519-11,527. https://doi.org/10.1002/2017GL074943.
Dias, F. B., M.D.; R. Fiedler, S. J. Marsland, C. M. Domingues, L. Clément, S. R. Rintoul, E. L. McDonagh, M. M. Mata, A. Savita (2020). Ocean heat storage in response to changing ocean circulation processes. Journal of Climate, 33(21), 9065-9082. https://doi.org/10.1175/JCLI-D-19-1016.1.
Downes, S. M., Sloyan, B. M., Rintoul, S. R., & Lupton, J. E. (2019). Hydrothermal heat enhances abyssal mixing in the Antarctic Circumpolar Current. Geophysical Research Letters, 46, 812–821. https://doi.org/10.1029/2018GL080410.
Gao, L., Rintoul, S. R., & Yu, W. (2017). Recent wind-driven change in Subantarctic Mode Water and its impact on ocean heat storage. Nature Climate Change, 8, 58-63. https://doi.org/10.1038/s41558-017-0022-8.
Kennicutt II, M. C., D. Bromwich, D. Liggett, B. Nja ̊stad, L. Peck, S. R. Rintoul, C. Ritz, M. J. Siegert, A. Aitken, C. M. Brooks, J. Cassano, S. Chaturvedi, D. Chen, K. Dodds, N. R. Golledge, C. Le Bohec, M. Leppe, A. Murray, P. C. Nath, M. N. Raphael, M. Rogan-Finnemore, D. M. Schroeder, L. Talley, T. Travouillon, D. G. Vaughan, L. Wang, A. T. Weatherwax, H. Yang, and S. L. Chown (2019). Sustained Antarctic Research: a 21st Century Imperative. One Earth, 1, 95-113. https://doi.org/10.1016/j.oneear.2019.08.014.
Lambelet, M., Tina van de Flierdt, Edward C V Butler, Andrew R Bowie, Steve R Rintoul, Ros J Watson, Tom Remenyi, Delphine Lannuzel, Mark Warner, Laura F Robinson, Helen C Bostock and Louisa I Bradtmiller (2018). The Neodynium isotope fingerprint of Adélie Coast Bottom Water. Geophysical Research Letters, 45(20), 11,247-211,256. https://doi.org/10.1029/2018GL080074.
Langlais, C. E., Lenton, A., Matear, R., Monselesan, D., Legrésy, B., Cougnon, E., & Rintoul, S. (2017). Stationary Rossby waves dominate subduction of anthropogenic carbon in the Southern Ocean. Scientific Reports, 7(1), 17076. https://doi.org/10.1038/s41598-017-17292-3.
Moreau, S., D. Lannuzel, J. Janssens, M. Arroyo, M. Corkill, E. Cougnon, C. Genovese, B. Legresy, A. Lenton, V. Puigcorbe, L. Ratnarajah, S. Rintoul, M. Rocca-Marti, M. Rosenberg, E. Shadwick, A. Silvano, P.G. Strutton, B. Tilbrook (2019). Sea Ice Meltwater and Circumpolar Deep Water Drive Contrasting Productivity in Three Antarctic Polynyas. Journal of Geophysical Research: Oceans, 124(5), 2943-2968. https://doi.org/10.1029/2019JC015071.
Newman, L., P. Heil, R. Trebilco, K. Katsumata, A. Constable, E. van Wijk, K. Assmann, J. Beja, P. Bricher, R.Coleman, Daniel Costa, S. Diggs, R. Farneti, S. Fawcett, S.T Gille, Katharine R Hendry, S. Henley, E. Hofmann, Ted Maksym, Matthew Mazloff, A. Meijers, M. M Meredith, S. Moreau, B. Ozsoy, R. Robertson, I. Schloss, O. Schofield, J. Shi, E. Sikes, I. J Smith, S. Swart, A. Wahlin, Guy Williams, Michael JM Williams, L. Herraiz-Borreguero, Stefan Kern, J. Lieser, R. A Massom, J. Melbourne-Thomas, P.Miloslavich, G.Spreen (2019). Delivering sustained, coordinated, and integrated observations of the Southern Ocean for global impact. Frontiers in Marine Science 6(433). https://doi.org/10.3389/fmars.2019.00433.
Pardo, P. C., Tilbrook, B., Langlais, C., Trull, T. W., & Rintoul, S. R. (2017). Carbon uptake and biogeochemical change in the Southern Ocean, south of Tasmania. Biogeosciences, 14(22), 5217-5237. https://www.biogeosciences.net/14/5217/2017/.
Rintoul, S. R. (2018). The global influence of localized dynamics in the Southern Ocean. Nature, 558(7709), 209-218. https://doi.org/10.1038/s41586-018-0182-3.
Rintoul, S. R., Chown, S. L., DeConto, R. M., England, M. H., Fricker, H. A., Masson-Delmotte, V., Naish, T. R., Siegert, M. J., & Xavier, J. C. (2018). Choosing the future of Antarctica. Nature, 558(7709), 233-241. https://doi.org/10.1038/s41586-018-0173-4.
Schlitzer, R. et al. (2018). The GEOTRACES Intermediate Data Product 2017. Chemical Geology, 493, 210-223 (Rintoul one of 238 authors) https://doi.org/10.1016/j.chemgeo.2018.05.040.
Snow, K., Rintoul, S. R., Sloyan, B. M., & Hogg, A. M. (2018). Change in Dense Shelf Water and Adélie Land Bottom Water Precipitated by Iceberg Calving. Geophysical Research Letters, 45(5), 2380-2387. https://doi.org/10.1002/2017GL076195.
Silvano, A., Foppert, A., Rintoul, S.R., Holland, P.R., Tamura, T., Kimura, N., Castagno, P., Falco, P., Budillon, G., Haumann, F. A., Naveira Garabato, A.C. and MacDonald, A. M. (2020) Recent recovery of Antarctic Bottom Water formation in the Ross Sea driven by climate anomalies. Nature Geoscience 13, 780–786. https://doi.org/10.1038/s41561-020-00655-3.
Silvano, A., Rintoul, S. R., Kusahara, K., Peña-Molino, B., van Wijk, E., Gwyther, D. E., & Williams, G. D. (2019). Seasonality of Warm Water Intrusions Onto the Continental Shelf Near the Totten Glacier. Journal of Geophysical Research: Oceans, 124(6), 4272-4289. https://doi.org/10.1029/2018JC014634.
Silvano, A., Rintoul, S. R., Peña-Molino, B., Hobbs, W. R., van Wijk, E., Aoki, S., Tamura, T., & Williams, G. D. (2018). Freshening by glacial meltwater enhances melting of ice shelves and reduces formation of Antarctic Bottom Water. Science Advances, 4(4). https://advances.sciencemag.org/content/4/4/eaap9467.
Thomas, G., S. G. Purkey, D. Roemmich, A. Foppert, S. R. Rintoul (2020). Spatial Variability of Antarctic Bottom Water in the Australian Antarctic Basin from 2018-2020 captured by Deep Argo. Geophysical Research Letters, 47(23), e2020GL089467. https://doi.org/10.1029/2020GL089467.
Wallace, L.O., E.M. van Wijk, S.R. Rintoul and B. Hally (2020). Bathymetry-constrained navigation of Argo floats under sea ice on the Antarctic continental shelf. Geophysical Research Letters, 47, e2020GL087019. https://doi.org/10.1029/2020GL087019.
Wåhlin, A. K., N. Steiger, E. Darelius, K. M. Assmann, M. S. Glessmer, H. K. Ha, L. C. Herraiz-Borreguero, C. Heuzé, A. Jenkins, T. W. Kim, A. K. Mazur, J. Sommeria, and S. Viboud, (2020) Ice front blocking of ocean heat transport to an Antarctic ice shelf. Nature, 578, 568–571. https://doi.org/10.1038/s41586-020-2014-5.