An autonomous sea state monitoring system for Australia’s icebreaker RSV Nuyina. The project aims to establish a world-class shipborne research infrastructure to measure air-sea interaction processes and integrate sea state measurements with lower atmosphere and upper ocean observations aboard research vessels. The project is timely and will deliver new standards in measuring fundamental processes and properties, sustaining Australian leadership in Antarctic and Southern Ocean expeditions, and underpinning the national effort to build the next generation of Earth system models.
The Southern Ocean plays a crucial role in the Earth’s climate system by storing incoming energy from the sun and transferring it back to the atmosphere in the form of heat and moisture, driving atmospheric circulation. Waves in the Southern Ocean contribute to a well-mixed layer that can store more heat and gases, including greenhouse gases like carbon dioxide, than any other latitude band on the planet. However, the effects of waves and sea ice on the climate system are not fully understood and remain poorly represented in climate models. In situ observations of the ocean and sea ice surface are critical to improving our understanding of these processes, but such observations are currently limited. Multidisciplinary expeditions that unite Earth science and engineering disciplines are beginning to explore the interplay of processes in the lower atmosphere, ocean surface, and subsurface in the Southern Ocean. These expeditions use pioneering shipborne imaging technology to record data on waves, wave breaking, surface current, and sea ice properties in support of lower atmosphere observations.
The equipment is installed on RSV Nuyina. It consists of:
- Stereo camera systems to recover the three-dimensional features of the ocean from synchronised snapshots in the visible light spectrum, and extrapolate properties of wave motion in both open ocean and sea ice;
- Sea ice cameras to capture (single) snapshots in the visible light spectrum of an extended portion of the sea ice surface and derive information on the sea state (concentration, type, floe size, leads/cracks, etc…);
- Bow cameras to capture (single) snapshots in the visible light spectrum of overturning broken ice at passage of the ship and infer sea ice thickness;
- Multi-spectral cameras to record the near infrared range (900-1700 nm), allowing the separation of snow cover, water and ice fractions from an image; and
- Infrared cameras to detect thermal inhomogeneities of sea ice.
The equipment is deployed on handrails at variable distance above the waterline (25-32m) and it is managed by an autonomous operating system. It operates continuously, producing a database with large diversity of images per voyage, including ideal (clear sky) conditions, low visibility (e.g. during snowfall) and low light (night photographs).
Alberello, A., Onorato, M., Bennetts, L.G., Vichi, M., Eayrs, C., MacHutchon, K. and Toffoli, A., 2019. Brief communication: Pancake ice floe size distribution during the winter expansion of the Antarctic marginal ice zone. The Cryosphere, 13(1), pp.41-48.
Alberello, A., Bennetts, L.G., Onorato, M., Vichi, M., MacHutchon, K., Eayrs, C., Ntamba, B., Benetazzo, A., Bergamasco, F., Nelli, F., Pattani, R., Clarke, H., Tersigni, I. and Toffoli, A., 2022. Three-dimensional imaging of waves and floes in the marginal ice zone during a cyclone. Nature Communications.
Tersigni, I., Alberello, A., Messori, G., Vichi, M., Onorato, M. and Toffoli, A., 2023. High- resolution thermal imaging in the Antarctic marginal ice zone: Skin temperature heterogeneity and effects on heat fluxes. Earth and Space Science, 10, e2023EA003078.
Public datasets can be downloaded from here.
Example of Photos
The University of Melbourne
The University of Adelaide
The University of Newcastle
University of Tasmania
Queensland University of Technology
Australian Antarctic Division
Commonwealth Scientific and Industrial Research Organisation
Pivot Maritime International Pty Ltd