Scalings for Submarine Melting at Tidewater Glaciers from Buoyant Plume Theory

Slater, Donald; Goldberg, Daniel; Nienow, Peter; Cowton, Tom

doi:10.1175/jpo-d-15-0132.1

Cited by 93 publications

(178 citation statements)

References 54 publications

Supporting

Mentioning

153

Contrasting

Order By: Relevance

“…[47]). Modelling studies indicate that submarine melt rate increases linearly with water temperature and with the subglacial discharge of meltwater runoff raised to a power between one-third and three-fourths [48][49][50], supporting the interpretation of these highly undercut zones as areas of enhanced plume-driven melting. [23] and Bevan et al [17], supplemented with additional data from digitisation of Landsat scenes.…”

Section: Processes Of Frontal Ablationmentioning

confidence: 75%

Glacier Calving in Greenland

Benn

Cowton

Todd

et al. 2017

Curr Clim Change Rep

View full text Add to dashboard Cite

In combination, the breakaway of icebergs (calving) and submarine melting at marine-terminating glaciers account for between one third and one half of the mass annually discharged from the Greenland Ice Sheet into the ocean. These ice losses are increasing due to glacier acceleration and retreat, largely in response to increased heat flux from the oceans. Behaviour of Greenland's marine-terminating ('tidewater') glaciers is strongly influenced by fjord bathymetry, particularly the presence of 'pinning points' (narrow or shallow parts of fjords that encourage stability) and overdeepened basins (that encourage rapid retreat). Despite the importance of calving and submarine melting and significant advances in monitoring and understanding key processes, it is not yet possible to predict the tidewater glacier response to climatic and oceanic forcing with any confidence. The simple calving laws required for ice-sheet models do not adequately represent the complexity of calving processes. New detailed process models, however, are increasing our understanding of the key processes and are guiding the design of improved calving laws. There is thus some prospect of reaching the elusive goal of accurately predicting future tidewater glacier behaviour and associated rates of sea-level rise.

show abstract

Section: Processes Of Frontal Ablationmentioning

confidence: 75%

Glacier Calving in Greenland

Benn

Cowton

Todd

et al. 2017

Curr Clim Change Rep

View full text Add to dashboard Cite

show abstract

“…Xu et al (2013) detected that this relationship of melt rate to thermal forcing depends on the amount of subglacial discharge released through a single channel at a tidewater glacier: the melt rate dependence to temperature has a power of 1.76 for small discharges and is lower for higher discharge. Slater et al (2016) found a power law dependence of melt rate on discharge, with the exponent 1/3 for both the CP and the LP models in a uniform stratification. For a linear stratification their study shows that the exponent enlarges to 3/4 for the CP model and to 2/3 for the LP model.…”

Section: Introductionmentioning

confidence: 90%

Simple models for the simulation of submarine melt for a Greenland glacial system model

2018

View full text Add to dashboard Cite

Abstract. Two hundred marine-terminating Greenland outlet glaciers deliver more than half of the annually accumulated ice into the ocean and have played an important role in the Greenland ice sheet mass loss observed since the mid1990s. Submarine melt may play a crucial role in the mass balance and position of the grounding line of these outlet glaciers. As the ocean warms, it is expected that submarine melt will increase, potentially driving outlet glaciers retreat and contributing to sea level rise. Projections of the future contribution of outlet glaciers to sea level rise are hampered by the necessity to use models with extremely high resolution of the order of a few hundred meters. That requirement in not only demanded when modeling outlet glaciers as a stand alone model but also when coupling them with highresolution 3-D ocean models. In addition, fjord bathymetry data are mostly missing or inaccurate (errors of several hundreds of meters), which questions the benefit of using computationally expensive 3-D models for future predictions. Here we propose an alternative approach built on the use of a computationally efficient simple model of submarine melt based on turbulent plume theory. We show that such a simple model is in reasonable agreement with several available modeling studies. We performed a suite of experiments to analyze sensitivity of these simple models to model parameters and climate characteristics. We found that the computationally cheap plume model demonstrates qualitatively similar behavior as 3-D general circulation models. To match results of the 3-D models in a quantitative manner, a scaling factor of the order of 1 is needed for the plume models. We applied this approach to model submarine melt for six representative Greenland glaciers and found that the application of a line plume can produce submarine melt compatible with observational data. Our results show that the line plume model is more appropriate than the cone plume model for simulating the average submarine melting of real glaciers in Greenland.

show abstract

“…A model based upon one-dimensional plume theory (e.g. Jenkins, 2011;Carroll et al, 2015;Slater et al, 2016) would be less computationally expensive and may allow some of these limitations to be addressed. However, such a model would not capture the strong surface currents driven by the plume which are important for the terminus morphology studied here.…”

Section: Plume Model and Undercuttingmentioning

confidence: 99%

Effects of undercutting and sliding on calving: a global approach applied to Kronebreen, Svalbard

et al. 2018

View full text Add to dashboard Cite

Abstract. In this paper, we study the effects of basal friction, sub-aqueous undercutting and glacier geometry on the calving process by combining six different models in an offlinecoupled workflow: a continuum-mechanical ice flow model (Elmer/Ice), a climatic mass balance model, a simple subglacial hydrology model, a plume model, an undercutting model and a discrete particle model to investigate fracture dynamics (Helsinki Discrete Element Model, HiDEM). We demonstrate the feasibility of reproducing the observed calving retreat at the front of Kronebreen, a tidewater glacier in Svalbard, during a melt season by using the output from the first five models as input to HiDEM. Basal sliding and glacier motion are addressed using Elmer/Ice, while calving is modelled by HiDEM. A hydrology model calculates subglacial drainage paths and indicates two main outlets with different discharges. Depending on the discharge, the plume model computes frontal melt rates, which are iteratively projected to the actual front of the glacier at subglacial discharge locations. This produces undercutting of different sizes, as melt is concentrated close to the surface for high discharge and is more diffuse for low discharge. By testing different configurations, we show that undercutting plays a key role in glacier retreat and is necessary to reproduce observed retreat in the vicinity of the discharge locations during the melting season. Calving rates are also influenced by basal friction, through its effects on near-terminus strain rates and ice velocity.

show abstract

Scalings for Submarine Melting at Tidewater Glaciers from Buoyant Plume Theory

Cited by 93 publications

References 54 publications

Glacier Calving in Greenland

Glacier Calving in Greenland

Simple models for the simulation of submarine melt for a Greenland glacial system model

Effects of undercutting and sliding on calving: a global approach applied to Kronebreen, Svalbard

Contact Info

Product

Resources

About