Subaqueous melting of Store Glacier, west Greenland from three‐dimensional, high‐resolution numerical modeling and ocean observations

Xu, Y.; Rignot, Eric; Fenty, Ian; Menemenlis, Dimitris; Flexas, María del Mar

doi:10.1002/grl.50825

Cited by 179 publications

(335 citation statements)

References 22 publications

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“…Turbidity measurements within and just outside of the surface plume (visually defined by the contrast in water colour), indicate that PluW sinks below the pycnocline of the SW after attaining the surface (Fig. 7), an observation that is in agreement with plume modelling at Store (Xu et al, 2013).…”

Section: Turbidity Analysis and Plume Observationsupporting

confidence: 78%

“…To date, several processes of interaction between fjord water and tidewater calving fronts have been observed, modelled and/or speculated upon including forced convection caused by buoyant subglacial fresh water (SgFW) discharged at depth and entraining AW as it rises (Jenkins, 2011;Mugford and Dowdeswell, 2011;Salcedo-Castro et al, 2011;Sciascia et al, 2013;Sole et al, 2012;Xu et al, 2012Xu et al, , 2013 as well as wind stress and tide-driven fjord circulation Sole et al, 2012;Straneo et al, 2010;Sutherland and Straneo, 2012). Furthermore, it is emerging that circulation in Greenland's deep fjords is more complex than the single convective cell (estuarine-like) circulation model that has been assumed previously in energymass balance calculations (Motyka et al, 2003;Rignot et al, 2010).…”

Section: N Chauché Et Al: Ice-ocean Interaction and Calving Front Mmentioning

confidence: 99%

“…Subglacial fresh water (SgFW) includes basal as well as surface runoff and is injected into the fjords at distinct portals at depth in the calving front. SgFW is very difficult to measure in its original state due to the vigorous mixing which occurs on its injection from the portal (Salcedo-Castro et al, 2011;Xu et al, 2012Xu et al, , 2013. Hence, SgFW is reasonably assumed to have the basic characteristics of θ = 0 • C and S = 0 PSU (Mortensen et al, 2013;Straneo et al, 2012).…”

Section: Water Types Present At the Glacier Frontmentioning

confidence: 99%

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Ice–ocean interaction and calving front morphology at two west Greenland tidewater outlet glaciers

et al. 2014

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Abstract. Warm, subtropical-originating Atlantic water (AW) has been identified as a primary driver of mass loss across the marine sectors of the Greenland Ice Sheet (GrIS), yet the specific processes by which this water mass interacts with and erodes the calving front of tidewater glaciers is frequently modelled and much speculated upon but remains largely unobserved. We present a suite of fjord salinity, temperature, turbidity versus depth casts along with glacial runoff estimation from Rink and Store glaciers, two major marine outlets draining the western sector of the GrIS during 2009 and 2010. We characterise the main water bodies present and interpret their interaction with their respective calving fronts. We identify two distinct processes of iceocean interaction which have distinct spatial and temporal footprints: (1) homogenous free convective melting which occurs across the calving front where AW is in direct contact with the ice mass, and (2) localised upwelling-driven melt by turbulent subglacial runoff mixing with fjord water which occurs at distinct injection points across the calving front. Throughout the study, AW at 2.8 ± 0.2 • C was consistently observed in contact with both glaciers below 450 m depth, yielding homogenous, free convective submarine melting up to ∼ 200 m depth. Above this bottom layer, multiple interactions are identified, primarily controlled by the rate of subglacial fresh-water discharge which results in localised and discrete upwelling plumes. In the record melt year of 2010, the Store Glacier calving face was dominated by these runoff-driven plumes which led to a highly crenulated frontal geometry characterised by large embayments at the subglacial portals separated by headlands which are dominated by calving. Rink Glacier, which is significantly deeper than Store has a larger proportion of its submerged calving face exposed to AW, which results in a uniform, relatively flat overall frontal geometry.

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Section: Turbidity Analysis and Plume Observationsupporting

confidence: 78%

Section: N Chauché Et Al: Ice-ocean Interaction and Calving Front Mmentioning

confidence: 99%

Section: Water Types Present At the Glacier Frontmentioning

confidence: 99%

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Ice–ocean interaction and calving front morphology at two west Greenland tidewater outlet glaciers

et al. 2014

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“…The direct effect of changes in temperature and salinity on the melt equations are well tested. Past studies using uniform ambient temperature and salinity conditions have found a linear relationship between increases in ambient fjord temperatures and melt rates, with the slope of the relationship dependent upon the discharge volume (P. R. Jenkins, 2011;Xu et al, 2013). Salinity, on the other hand, has been shown to have a negligible effect on melt rates (D. M. .…”

Section: Plume Model and Undercuttingmentioning

confidence: 99%

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

et al. 2018

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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.

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“…At the front of marine terminating glaciers, freshwater plumes are generated by subglacial discharge and submarine melting. The presence of multiple plumes may affect glacial melting (Xu et al 2013;Kimura et al 2014) through the modified entrainment in the interacting plumes.…”

Section: Introductionmentioning

confidence: 99%

Entrainment in two coalescing axisymmetric turbulent plumes

Cenedese

Linden

2014

J. Fluid Mech.

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A model of the total volume flux and entrainment occurring in two coalescing axisymmetric turbulent plumes is developed and compared with laboratory experiments. The dynamical evolution of the two plumes is divided into three regions. In region 1, where the plumes are separate, the entrainment in each plume is unaffected by the other plume, although the two plumes are drawn together due to the entrainment of ambient fluid between them. In region 2 the two plumes touch each other but are not yet merged. In this region the total entrainment is a function of both the dynamics of the touching plumes and the reduced surface area through which entrainment occurs. In region 3 the two plumes are merged and the entrainment is equivalent to that in a single plume. We find that the total volume flux after the two plumes touch and before they merge increases linearly with distance from the sources, and can be expressed as a function of the known total volume fluxes at the touching and merging heights. Finally, we define an 'effective' entrainment constant, α eff , as the value of α needed to obtain the same total volume flux in two independent plumes as that occurring in two coalescing plumes. The definition of α eff allows us to find a single expression for the development of the total volume flux in the three different dynamical regions. This single expression will simplify the representation of coalescing plumes in more complex models, such as in large-scale geophysical convection, in which plume dynamics are not resolved. Experiments show that the model provides an accurate measure of the total volume flux in the two coalescing plumes as they evolve through the three regions.

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Subaqueous melting of Store Glacier, west Greenland from three‐dimensional, high‐resolution numerical modeling and ocean observations

Cited by 179 publications

References 22 publications

Ice–ocean interaction and calving front morphology at two west Greenland tidewater outlet glaciers

Ice–ocean interaction and calving front morphology at two west Greenland tidewater outlet glaciers

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

Entrainment in two coalescing axisymmetric turbulent plumes

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