Arctic Ice research at an Oceans conference ? Why not !

The Arctic is becoming a hotbed of activity with record-breaking soaring global temperatures seeing more melting of the polar ice caps. Accelerating glacial melt in the Arctic has led to a sea-level rise of 7.5 mm between 1992 and 2011 which forms 25% of the current rate of sea level rise ^[1].

The largest and most permanent bodies of ice in the Arctic have melted faster since 2000 than in the previous decade ^[2].

The years 2005-2010 are reported to be the warmest period ever recorded in the region until 2011. Previously, we had reported an article stating how signs of climate change can be seen at the Arctic tree line ^[3].

Thus, it is not surprising that the Arctic theme saw a fair amount of interest at the 2019 Oceans Conference in Marseille, France. Arctic research presented at the conference spanned as diverse fields such as underwater acoustic instrumentation, satellite-based monitoring of ice, use of autonomous robots in the region and even under-ice acoustic communication.

Flexible cost-efficient monitoring using gliders


Researchers collaborating across several institutes from Norway introduced an innovative, flexible and cost-efficient approach towards offshore monitoring and data management using underwater and surface glider vehicles [4]. The objective of the approach was to provide more high-quality sampling of marine data and a more flexible sampling scheme. This could, in turn, lead to a reduction in costs and carbon footprint. The researchers envisage that the potential applications of this approach include field survey, zooplankton mapping, sea mammal detection, and real-time data assimilation into an ocean model.

Representational image - A calving glacier ¹

Satellite-based ice-thickness estimation


A student participant from Memorial university, Canada, presented a satellite-based method to estimate sea-ice thickness over large regions [5]. This paper was also part of the student poster competition. The student presented results obtained using data from the TechDemoSat-1 satellite, and validated their accuracy against reference data over the years 2014-2018.


Acoustic ice-thickness estimation


A researcher from the Institute of Applied Physics of the Russian Academy of Sciences, presented an acoustic approach towards a similar objective – measuring ice thickness. He presented an active acoustic method to measure ice thickness using an upward pointing wave-gauge sonar [6]. The idea was to shoot sound pulses at the ice sheet, to observe the time and amplitude of the returns to gauge the thickness of ice. Results were presented from tests conducted in April 2019, using an impulse sonar ‘Streika’ developed for this purpose.


Acoustic communication and localization under ice


Researchers from Woods Hole Oceanographic Institution presented results from a small experimental network of ocean sensors linked by acoustic communications [7]. These were tested in March-April of 2017 in shore-fast ice near Thule Air Base in northern Greenland. Initial results showed that reliable communication was possible in the Arctic over long distances - at 20-25 km for most data rates. The researchers also showed that moderate acoustic connectivity was possible from 25-35 km. In related work done on signal processing [8], researchers from the Chinese Academy of Sciences, Beijing, China presented a technique for localizing an under-ice acoustic source using matched-field processing. The researchers conducted experiments in the Northern part of the Yellow sea to localize sources at ranges of 1.5 km and 2.7 km.


Estimation of algal biomass in polar ice


Another Arctic-related poster presented work on spectral estimation of algal biomass in polar ice [9]. This would provide a crucial piece of information because ice algae is an important food source in the polar marine ecosystem. Long-term continuous measurement of algae biomass based on techniques such as these can be used to study the long-term dynamic changes of marine ecosystem in the polar regions [9]. The work was presented by researchers from Zhejiang University. They estimated the biomass by comparing the spectral content of polar ice against those of pure sea ice to gauge the chlorophyll content.


The research presented at the conference not only covered a variety of Arctic-related applications, but also originated from numerous institutions from several countries – China, Russia, Canada and Norway amongst them. Given that the melting ice is drawing researchers’ attention to the Arctic as a status monitor for global climate change, a potential shipping route for trade, and a source of natural resources, it seems inevitable that more countries would undertake scientific research to understand this region better in the coming years.




Read coverage on a Hydrography workshop at Oceans 2019 conference, Oceans-related coverage on Careers for students and Young Professionals, and more on Oceans 2019 Marseille at OES Beacon


References

• [1] O. Glowacki, G. Deane, and M. Moskalik, “The Intensity, Directionality, and Statistics of Underwater Noise From Melting Icebergs,” Geophysical Research Letters, no. 9.
• [2] W. Meier, S. Gerland, M. Granskog, J. Key, C. Haas, G. Hovelsrud, K. Kovacs, A. Makshtas, C. Michel, D. Perovich, J. Reist, and B. van Oort, “Arctic Climate Issues 2011,” Oslo, Tech. Rep., 2011. [Online]. Available: http://www.amap.no/documents/doc/arctic-climate-issues-2011-changes-in-arctic-snow-water-ice-and-permafrost/129
• [3] Signs of Climate Change at the Arctic Tree line, https://earthzine.org/signs-of-climate-change-at-arctic-tree-line/
• [4] Camus, L. et al Autonomous surface and underwater vehicles reveal new discoveries in the Arctic Ocean, Oceans 2019 Marseille
• [5] Qingyun Yan, and Weimin Huang, “Sea Ice Thickness Estimation From TechDemoSat-1 Data”, Oceans 2019 Marseille
• [6] Yuriy Titchenko et al., “Experimental study of the possibility of using an underwater acoustic wave gauge in freezing waters to measure the thickness of the ice cover”, Oceans 2019 Marseille
• [7] Lee Freitag, Sandipa Singh, Keenan Ball, Tyler Johnson, Dennis Giaya, Andreas Muenchow and Peter Washam, “Experimental Results in Acoustic Communications Under Shore-Fast Greenland Ice”, Oceans 2019 Marseille
• [8] Chonglei Liu et al., “Matched-field localization in under-ice shallow water environment”, Oceans 2019 Marseille
• [9] Zexia Qiu et al. “Method for Long-term Estimating Ice Algae Biomass Based on Spectral Attenuation Characteristics of the Sea Ice”, Oceans 2019 Marseille

¹ The image "calving glacier" by Doryce is licensed under CC BY 2.0