In:
The Cryosphere, Copernicus GmbH, Vol. 16, No. 4 ( 2022-04-07), p. 1181-1196
Abstract:
Abstract. The rate of ocean-driven retreat of Greenland's tidewater glaciers remains
highly uncertain in predictions of future sea level rise, in part due to
poorly constrained glacier-adjacent water properties. Icebergs and their
meltwater contributions are likely important modifiers of fjord water
properties, yet their effect is poorly understood. Here, we use a 3-D ocean
circulation model, coupled to a submarine iceberg melt module, to
investigate the effect of submarine iceberg melting on glacier-adjacent
water properties in a range of idealised settings. Submarine iceberg melting
can modify glacier-adjacent water properties in three principal ways: (1) substantial cooling and modest freshening in the upper ∼50 m
of the water column; (2) warming of Polar Water at intermediate depths due
to iceberg melt-induced upwelling of warm Atlantic Water and; (3) warming
of the deeper Atlantic Water layer when vertical temperature gradients
through this layer are steep (due to vertical mixing of warm water at
depth) but cooling of the Atlantic Water layer when vertical temperature
gradients are shallow. The overall effect of iceberg melt is to make
glacier-adjacent water properties more uniform with depth. When icebergs
extend to, or below, the depth of a sill at the fjord mouth, they can cause
cooling throughout the entire water column. All of these effects are more
pronounced in fjords with higher iceberg concentrations and deeper iceberg
keel depths. These iceberg melt-induced changes to glacier-adjacent water
properties will reduce rates of glacier submarine melting near the surface, increase them in the Polar Water layer, and cause typically modest
impacts in the Atlantic Water layer. These results characterise the
important role of submarine iceberg melting in modifying ice sheet-ocean
interaction and highlight the need to improve representations of fjord
processes in ice sheet scale models.
Type of Medium:
Online Resource
ISSN:
1994-0424
DOI:
10.5194/tc-16-1181-2022
Language:
English
Publisher:
Copernicus GmbH
Publication Date:
2022
detail.hit.zdb_id:
2393169-3
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