Sermilik, Greenland 3D iceberg data, summer 2017-2019

• Main Authors: Kristin Schild, David Sutherland, Pedro Elosegui, Daniel Duncan
• Format: Dataset
• Language: unknown
• Published: Arctic Data Center 2021
• Subjects: Icebergs; GPS; Drone; Multibeam; Point cloud; Structure from Motion; Greenland; Sutherland; East Greenland; Ice Sheet; North Atlantic; Sermilik
• Online Access: https://search.dataone.org/view/urn:uuid:b318b5f2-e7cb-40f8-b0b9-42303a0331c7

This dataset is comprised of raw on-iceberg Geographic Positioning System (GPS) data, sound-speed corrected iceberg subsurface multibeam data (not corrected for iceberg movement), and iceberg surface three dimensional (3D) point clouds, constructed using structure from motion (SFM) of drone imagery. Data were collected during the summers of 2017, 2018, and 2019 in Sermilik Fjord, East Greenland. Processing methods for these data are explained in the manuscript 'Measurements of iceberg melt rates using high-resolution GPS and iceberg surface scans' by Kristin M. Schild, David A. Sutherland, Pedro Elosegui and Daniel Duncan, published in Geophysical Research Letters in 2021 (doi: 10.1029/2020GL089765). The abstract and plain language summary (focusing solely on 2 of the 2017 icebergs) for that paper are included below. Abstract Increasing freshwater input to the subpolar North Atlantic through iceberg melting can influence fjord-scale to basin-scale ocean circulation. However, the magnitude, timing, and distribution of this freshwater have been challenging to quantify due to minimal direct observations of subsurface iceberg geometry and melt rates. Here we present novel in situ methods capturing iceberg change at high-temporal and -spatial resolution using four high-precision GPS units deployed on two large icebergs greater than 500 meters (m) in length. In combination with measurements of surface and subsurface geometry, we calculate iceberg melt rates between 0.10–0.27 m/day over the 9-day survey. These melt rates are lower than those proposed in previous studies, likely due to using individual subsurface iceberg geometries in calculations. In combining these new measurements of iceberg geometry and melt rate with the broad spatial coverage of remote sensing, we can better predict the impact of increasing freshwater injection from the Greenland Ice Sheet. Plain Language Summary The acceleration of Greenland glaciers has led to an increase of icebergs discharged in nearby waters. As icebergs melt, they release freshwater into salty ocean waters, impacting local circulation. In order to understand how global circulation will change in the future, we need accurate iceberg melt rates. To do this, we use measurements of mass loss from on-iceberg GPS units, and 3D iceberg geometry constructed from aerial drone and subsurface sonar data. We found melt rates smaller than previous studies and strong evidence for variable overall melt rates with different keel depths and over time. This study is the first of its kind to calculate melt rates using exact iceberg geometry. To better predict iceberg impacts, future iceberg studies should take these geometry results into account.