Abstract
Antarctic tabular icebergs are important active components in the ice sheet-ice shelf-ocean system. Seafloor topography is the key factor that affects the drifting and grounding of icebergs, but it has not been fully investigated. This study analyzes the impact of seafloor topography on the drifting and grounding of Antarctic tabular icebergs using Bedmap-2 datasets and iceberg route tracking data from Brigham Young University. The results highlight the following points. (1) The quantitative distributions of iceberg grounding events and the tracking points of grounded icebergs are mainly affected by iceberg draft and reach their peak values in sea water with depths between 200 m and 300 m. The peak tracking point number and linear velocity of free-drifting icebergs are found in the Antarctic Slope Front (water depth of approximately 500 m). (2) The area of possible grounding regions of small-scale icebergs calved from ice shelf fronts accounts for 28% of the sea area at water depths less than 2000 m outside the Antarctic coastline periphery (3.62 million km2). Their spatial distribution is mainly around East Antarctica and the Antarctic Peninsula. The area of possible grounding regions of large tabular icebergs with long axes larger than 18.5 km (in water depths of less than 800 m) accounts for 74% of the sea area. (3) The iceberg drifting velocity is positively correlated with ocean depth in areas where the depth is less than 2000 m (R=0.85, P<0.01). This result confirms the effect of water depth variations induced by seafloor topography fluctuations on iceberg drifting velocity.
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Acknowledgements
We thank the British Antarctic Survey for providing the Bedmap-2 dataset, and Brigham Young University for making available the iceberg tracking data. This study was supported by the National Key Research and Development Program of China (Grant No. 2016YFA0600103), the National Natural Science Foundation of China (Grant Nos. 41406211, 41476161, 41676182 & 41676176), the National Basic Research Program of China (Grant No. 2012CB957704), the Key Laboratory Research Fund of the National Administration of Surveying, Mapping and Geoinformation of China (Grant No. 201416), the Specialized Research Fund for the Doctoral Program of Higher Education (Grant No. 20120003110030), and the Project of International Cooperation and Exchanges CHINARE (Grant No. 201611).
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Li, T., Liu, Y., Cheng, X. et al. The effect of seafloor topography in the Southern Ocean on tabular iceberg drifting and grounding. Sci. China Earth Sci. 60, 697–706 (2017). https://doi.org/10.1007/s11430-016-9014-5
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DOI: https://doi.org/10.1007/s11430-016-9014-5