Impact of Two Plumes' Interaction on Submarine Melting of Tidewater Glaciers: A Laboratory Study

Cenedese, C.; Gatto, V.M.

doi:doi:10.1175/JPO-D-15-0171.1

Impact of Two Plumes' Interaction on Submarine Melting of Tidewater Glaciers: A Laboratory Study

Title

Impact of Two Plumes' Interaction on Submarine Melting of Tidewater Glaciers: A Laboratory Study

Author

Cenedese, C.
Gatto, V.M.

Faculty

Civil Engineering and Geosciences

Department

Hydraulic Engineering

Date

2016-01-21

Abstract

Idealized laboratory experiments investigate the glacier–ocean boundary dynamics near a vertical glacier in a two-layer stratified fluid. Discharge of meltwater runoff at the base of the glacier (subglacial discharge) enhances submarine melting. In the laboratory, the effect of multiple sources of subglacial discharge is simulated by introducing freshwater at freezing temperature from two point sources at the base of an ice block representing the glacier. The buoyant plumes of cold meltwater and subglacial discharge water entrain warm ambient water, rise vertically, and interact within a layer of depth H2 if the distance between the sources x0 is smaller than H2?/0.35, where ? is the entrainment constant. The plume water detaches from the glacier face at the interface between the two layers and/or at the free surface, as confirmed by previous numerical studies and field observations. A plume model is used to explain the observed nonmonotonic dependence of submarine melting on the sources’ separation. The distance between the two sources influences the entrainment of warm water in the plumes and consequently the amount of submarine melting and the final location of the meltwater within the water column. Two interacting plumes located very close together are observed to melt approximately half as much as two independent plumes. The inclusion, or parameterization, of the dynamics regulating multiple plumes’ interaction is therefore necessary for a correct estimate of submarine melting. Hence, the distribution and number of sources of subglacial discharge may play an important role in glacial melt rates and fjord stratification and circulation.

Subject

geographic location/entity
glaciers
circulation/ dynamics
buoyancy
entrainment
ocean dynamics;
small scale processes
models and modeling
Laboratory/physical models

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http://resolver.tudelft.nl/uuid:59b7d2e6-3a4d-40ef-b852-3789bb53f19d

Publisher

American Meteorological Society

Embargo date

2016-07-21

ISSN

0022-3670

Source

https://doi.org/10.1175/JPO-D-15-0171.1