Hydraulic suppression of basal glacier melt in sill fjords

Using a conceptual model, we examine how hydraulically controlled exchange flows in silled fjords affect the relationship between the basal glacier melt and the features of warm intermediate Atlantic Water (AW) outside the fjords. We show that an exchange flow can be forced to transit into the hydra...

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Bibliographic Details
Published in:The cryosphere 2023-06, Vol.17 (6), p.2455-2476
Main Authors: Nilsson, Johan, van Dongen, Eef, Jakobsson, Martin, O'Regan, Matt, Stranne, Christian
Format: Article
Language:English
Subjects:
Analysis
Exchanging
Fjords
Geometry
Glacier melting
Glaciers
Heat
Heat transport
Hydraulics
Limiting factors
Ocean circulation
Salinity
Surface-ice melting
Temperature
Temperature rise
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Summary:Using a conceptual model, we examine how hydraulically controlled exchange flows in silled fjords affect the relationship between the basal glacier melt and the features of warm intermediate Atlantic Water (AW) outside the fjords. We show that an exchange flow can be forced to transit into the hydraulic regime if the AW interface height decreases, the AW temperature increases, or the production of glacially modified water is boosted by subglacial discharge. In the hydraulic regime, the heat transport across the sill becomes a rate-limiting factor for the basal melt, which is suppressed. An interplay between processes near the ice–ocean boundary and the hydraulically controlled exchange flow determines the melt dynamics, and the sensitivity of the basal melt to changes in the AW temperature is reduced. The model results are discussed in relation to observations from the Petermann, Ryder, and 79∘ N glaciers in northern Greenland.
ISSN:1994-0424
1994-0416
1994-0424
1994-0416
DOI:10.5194/tc-17-2455-2023