In polar regions, a large component of the ice loss that feeds sea level rise occurs due to two mechanisms – calving and submarine melting at the glacier-ocean interface. The underwater melting of glacier ice by sea water produces a sound similar to ‘frying bacon’ due to explosion of bubbles underwater. This sound travels over long distances underwater. Thus, it is a promising medium to characterize ice-loss in large areas using relatively cheap recording equipment over longer periods than visual systems, and with more resolution than conventional methods such as satellite imagery. We have been exploring how acoustic monitoring can be used to characterize the glacier-ocean interface, in collaboration with researchers from the Scripps Institution of Oceanography, the Institute of Geophysics, Polish Academy of Sciences, the Arctic University of Norway (Tromso) and the Norwegian University of Science and Technology.
The Arctic is one of the focal points of global climate change, with surface temperatures rising twice as fast as the rest of the world. A significant component of the global sea-level rise is attributed to melting glaciers and ice-caps such as those found in Svalbard. Passive acoustic monitoring techniques are suitable for extracting information on the climate-change related mechanisms in these glacial bays, because sound data is simple to acquire, covers a large area, and can facilitate long-term monitoring. The Antarctic, on the other hand, holds the world’s largest store of freshwater, and is potentially expected to play a larger part in sea level in decades to come. Towards this, we have undertaken field campaigns in both the Arctic and Antarctic, where we have obtained acoustic recordings from sensor arrays, done robotic surveys with acoustic and vision sensors near the glacier termini, and drone-based studies. These studies will allow us to develop a deeper understanding of the submarine melting process and the underwater environments in these regions.
We are working on developing signal processing techniques to estimate the glacier melt rate from data recorded in these regions. These will guide our strategy to build acoustic systems to monitor the ice-loss over a long period. Such long-term acoustic-based estimates of ice-loss and its components can help improve predictions of sea-level rise, which pose an increasing risk to coastal states like Singapore.
Field campaigns undertaken as part of this include:
The Arctic is one of the focal points of global climate change, with surface temperatures rising twice as fast as the rest of the world. A significant component of the global sea-level rise is attributed to melting glaciers and ice-caps such as those found in Svalbard. Passive acoustic monitoring techniques are suitable for extracting information on the climate-change related mechanisms in these glacial bays, because sound data is simple to acquire, covers a large area, and can facilitate long-term monitoring. The Antarctic, on the other hand, holds the world’s largest store of freshwater, and is potentially expected to play a larger part in sea level in decades to come. Towards this, we have undertaken field campaigns in both the Arctic and Antarctic, where we have obtained acoustic recordings from sensor arrays, done robotic surveys with acoustic and vision sensors near the glacier termini, and drone-based studies. These studies will allow us to develop a deeper understanding of the submarine melting process and the underwater environments in these regions.
We are working on developing signal processing techniques to estimate the glacier melt rate from data recorded in these regions. These will guide our strategy to build acoustic systems to monitor the ice-loss over a long period. Such long-term acoustic-based estimates of ice-loss and its components can help improve predictions of sea-level rise, which pose an increasing risk to coastal states like Singapore.
Field campaigns undertaken as part of this include:
- 2024: Antarctic Peninsula (in partnership with Lindblad Expeditions and National Geographic)
- 2023: Hornsund fjord, Svalbard
- 2023: Kongsfjorden, Svalbard
- 2019: Hornsund fjord, Svalbard
Publications from this project include:
Journals:
- H. Vishnu, G. Deane, O. Glowacki, M. Chitre, H. Johnson, M. Moskalik and D. Stokes, “Depth-dependence of the underwater noise emission from melting glacier ice,” Journal of the Acoustical Society of America Express Letters, 3 (020801), Feb 2023. [ DOI | .pdf ]
- H. Vishnu, G. Deane, M. Chitre, O. Glowacki, D. Stokes, and M. Moskalik, “Vertical directionality and spatial coherence of the sound field in glacial bays in Hornsund Fjord,” Journal of the Acoustical Society of America, vol. 148, no. 6, 2020. © 2020 Acoustical Society of America. [ DOI | .pdf ]. See a video describing this paper here.
Invited talks and Conferences:
- H. Vishnu, “Using technology to demystify climate change,” NUS Cities Symposium, Sep 2023, Singapore (Keynote). [ http ]
- M. Chitre, G. Deane, O. Glowacki, D. Stokes, H. Vishnu and H. Johnson, “Can low-cost robots help us understand ice-ocean interactions leading to global sea level rise?,” in International Conference on Robotics and Automation (ICRA 2022), 23 May 2022. (Invited). [ http ]
- G. Deane, O. Glowacki, Hari Vishnu, D. Stokes, M. Chitre, H. Johnson, J. Tegowski, “Recent Progress in Monitoring Tidewater Glaciers with Passive Cryoacoustics,” in 6th Underwater Acoustics conference and exhibition, Greece, June 2021. (Invited). [ http ]
- O. Glowacki, G. Deane, D. Stokes, P. Lewinska, M. Chitre, H. Vishnu, M. Moskalik, D. Maniktala, H. Johnson and E. Weidner, “A Multi-Method Observation of Glacier Frontal Ablation and Related Processes in Hornsund Fjord, Svalbard,” in AGU Fall Meeting 2024, Washington, D.C., 12 December 2024. [ http ]
- E. Weidner, G. Deane, F. Straneo, H. Vishnu and M. Chitre, “Broadband echosounder derived measurements of 3D geometry of a subglacial discharge plume in Hornsund Fjord,” in AGU Fall Meeting 2024, Washington, D.C., 9 December 2024. [ http ]
- H. Johnson, G. Deane, O. Glowacki, D. Stokes, M. Chitre, H. Vishnu, E. Weidner and K. Gollamudi, “Working Towards Passive Acoustic Measurements of Submarine Melting at Marine-terminating Glaciers,” in AGU Fall Meeting 2024, Washington, D.C., 11 December 2024. [ http ]
- H. Vishnu, T. Y. Lin, M. Chitre, B. Kalyan and E. J. Venables, “Estimating Floating Ice Coverage in Tidewater Glacier Bays Automatically from Aerial Imagery,” in MTS/IEEE OCEANS 2024, Halifax, 23-26 September 2024. [ http | pdf ]
- H. Johnson, G. Deane, O. Glowacki, D. Stokes, M. Chitre, H. Vishnu and E. Weidner, “Acoustic observations of individual bubble release events from melting glacier ice in an arctic fjord,” in ASA Meetings 2024, Ottawa, Canada, 13-17 May 2024. [ DOI | http ]
- H. Johnson, G. Deane, D. Stokes, O. Glowacki, M. Moskalik, M. Chitre, Hari Vishnu, “Predicting the acoustic energy radiated by melting glacier ice,” (Accepted) in ASA Meeting, Dec 2021 [ http ]
- H. Johnson, G. Deane, D. Stokes, O. Glowacki, M. Moskalik, M. Chitre, Hari Vishnu, “Understanding the acoustic signal of submarine melting of glacier ice,” (Accepted) in Ocean Sciences Meeting 2022, Feb 2022 [ http ]
- H. Johnson, H. Vishnu, G. Deane, P. J. Tuckman, O. Glowacki, and M. Moskalik, “Depth dependence of acoustic signals produced by bubble release events in melting glacier ice,” in The Journal of the Acoustical Society of America – Acoustics Virtually Everywhere, vol. 148, pp. 2483–2483, December 2020. [ DOI | .pdf ]
- H. Vishnu, G. Deane, M. Chitre, D. Stokes, and O. Glowacki, “Vertical line array measurements of the sound radiated by melting glaciers in Hornsund Fjord,” in The Journal of the Acoustical Society of America – Acoustics Virtually Everywhere, vol 148, pp. 2483–2483, December 2020. [ DOI | .pdf | http ]
- G. Deane, O. Glowacki, D. Stokes, M. Moskalik, M. Chitre, and H. Vishnu, “Measuring tidewater glacier melt rates with underwater noise,” in Ocean Sciences meeting, (San Diego), February 2020 [ http ]