GreenFjordFIBER

Submarine Distributed Acoustic– and Temperature Sensing (DAS/DTS) along the Calving Front of a Greenlandic Tidewater Outlet Glacier

The GreenFjordFIBER dataset is currently under embargo, unrestricted access will be granted starting January 1, 2027.

Abstract

As the nexus of ice, ocean and atmosphere, calving fronts of tidewater outlet glaciers control dynamic mass loss and the stability of the Greenland Ice Sheet (GrIS). As global warming changes Greenland’s coastal landscapes –perhaps most visibly through the inland retreat of calving fronts– dynamic processes acting on these boundaries not only impact future tidewater glacier evolution, but regulate the stability of almost the entire GrIS. This project will quantify important, interconnected physical processes at the calving front of Eqalorutsit Kangilliit Sermiat (EKaS; also known as Qajuuttap Sermia), a tidewater outlet glacier of the GrIS, with unprecedented spatio-temporal resolution. We will test the hypothesis that during the spring-to-summer transition period, ice–ocean interactions exhibit a regime change from one where melt and calving are dominated by temperature to one where variability in subglacial discharge is the dominant driver of melt and calving. We will use a combination of traditional and cutting-edge sensor technology, most prominently including Distributed Temperature Sensing (DTS) and Distributed Acoustic Sensing (DAS) along a bespoke subsea optical fiber to measure ocean temperature, calving, subglacial discharge and subglacial melt with high spatial and temporal resolution. Our project benefits from a collaboration with the Swiss Polar Institute.

Calving front of Eqalorutsit Kangilliit Sermiat (EKaS), Greenland (61.31° N, -45.78° W) 

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Dataset Description

GreenFjordFIBER uses Distributed Acoustic- and Temperature Sensing (DAS/DTS) on a self-deployed submarine fiber-optic cable along the calving front of Eqalorutsit Kangillit Sermiat (Qajuuttap Sermia) in South Greenland for measuring ice-ocean interactions. The DAS and DTS interrogators were solar powered and located east of the calving front on the northern shore of Qajuuttap bay. From there, the fiber-optic cable leads for the first 250 m on land in a ~20 cm deep trench north-westward along the shoreline where it enters the water over a rock slab. In the fjord, the cable was deployed on the seafloor without trenching. From the shore of the bay, the cable continues for ~500 m southward in up to 20 m deep water. It then changes direction south-westward towards the calving front. As the cable passes the submarine ridge and exits the bay, it lies at a depth of 280-300 m and a distance between 500-1000 m from the calving front until it reaches the western bedrock shore of the fjord, where it ascends steeply upward from the fjord bottom onto land. From 9-29 August (21 days), we continuously measured strain and temperature along the fiber-optic cable with a Sintela ONYXTM interrogator for DAS and a Silixa XT-DTSTM M interrogator for DTS. Throughout our 21 day long fiber-optic measurements, the operational cable length shortened by multiple kilometers due to damages to the fiber-optic cable.

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DOI:

Citation:

Gräff, D., Lipovsky, B.P. (2024) GreenFjordFIBER: Submarine Distributed Acoustic– and Temperature Sensing (DAS/DTS) along the Calving Front of a Greenlandic Tidewater Outlet Glacier [Data Set]. Seattle, Washington USA. FiberLab, University of Washington.

License: Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International

NSF Grant #2338502 Collaborative Research: GreenFjord-FIBER, Observing the Ice-Ocean Interface with Exceptional Resolution