An Improved and Observationally‐Constrained Melt Rate Parameterization for Vertical Ice Fronts of Marine Terminating Glaciers

Schulz, Kirstin; Nguyen, Anhco; Pillar, Helen

doi:10.1029/2022gl100654

Cited by 18 publications

(15 citation statements)

References 45 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

Section: Introductionmentioning

confidence: 71%

“…In this study, we extend results from a recently proposed parameterization for vertical glacial ice fronts, which proposed modifying unbounded plume theory using empirical constraints for the efficiency of turbulent heat and salt transfer to match observational data (Schulz et al, 2022). Schulz et al (2022) also proposed a transfer function that merges the velocity-dependent (shear-dominated) and velocity-independent (buoyancy-dominated) melt regimes, based on best empirical fits to observations. This results in a significantly higher baseline buoyancy-dominated melt rate (in the absence of external flow) than previous literature (e.g., Kerr and McConnochie (2015)) and does not provide a physical explanation why these baseline melt rates should be higher.…”

Section: Introductionmentioning

confidence: 71%

See 1 more Smart Citation

Improved Parameterizations of Vertical Ice‐Ocean Boundary Layers and Melt Rates

Zhao,

Skyllingstad,

Nash

2024

Geophysical Research Letters

View full text Add to dashboard Cite

Buoyancy fluxes and submarine melt rates at vertical ice‐ocean interfaces are commonly parameterized using theories derived for unbounded free plumes. A Large Eddy Simulation is used to analyze the disparate dynamics of free plumes and wall‐bounded plumes; the distinctions between the two are supported by recent theoretical and experimental results. Modifications to parameterizations consistent with these simulations are tested and compared to results from numerical and laboratory experiments of meltwater plumes. These modifications include 50% weaker entrainment and a distinct plume‐driven friction velocity in the shear boundary layer up to 8 times greater than the externally‐driven friction velocity. Using these updated plume parameter modifications leads to 40 times the ambient melt rate predicted by commonly used parameterizations at vertical glacier faces, which is consistent with observed melt rates at LeConte Glacier, Alaska.

show abstract

Section: Introductionmentioning

confidence: 71%

Section: Introductionmentioning

confidence: 71%

Improved Parameterizations of Vertical Ice‐Ocean Boundary Layers and Melt Rates

Zhao,

Skyllingstad,

Nash

2024

Geophysical Research Letters

View full text Add to dashboard Cite

show abstract

“…Due to the prevalence of undercutting previously observed at marine-terminating glaciers, models of submarine melting and iceberg calving have primarily used idealized terminus geometries that are either purely undercut or vertical (e.g. Slater and others, 2017; Holmes and others, 2023; Schulz and others, 2022). Our results, however, show that despite high melt rates observed across the glacier terminus, LeConte Glacier is largely overcut.…”

Section: Discussionmentioning

confidence: 99%

Persistent overcut regions dominate the terminus morphology of a rapidly melting tidewater glacier

et al. 2023

View full text Add to dashboard Cite

Frontal ablation, the combination of submarine melting and iceberg calving, changes the geometry of a glacier's terminus, influencing glacier dynamics, the fate of upwelling plumes and the distribution of submarine meltwater input into the ocean. Directly observing frontal ablation and terminus morphology below the waterline is difficult, however, limiting our understanding of these coupled ice–ocean processes. To investigate the evolution of a tidewater glacier's submarine terminus, we combine 3-D multibeam point clouds of the subsurface ice face at LeConte Glacier, Alaska, with concurrent observations of environmental conditions during three field campaigns between 2016 and 2018. We observe terminus morphology that was predominately overcut (52% in August 2016, 63% in May 2017 and 74% in September 2018), accompanied by high multibeam sonar-derived melt rates (4.84 m d−1 in 2016, 1.13 m d−1 in 2017 and 1.85 m d−1 in 2018). We find that periods of high subglacial discharge lead to localized undercut discharge outlets, but adjacent to these outlets the terminus maintains significantly overcut geometry, with an ice ramp that protrudes 75 m into the fjord in 2017 and 125 m in 2018. Our data challenge the assumption that tidewater glacier termini are largely undercut during periods of high submarine melting.

show abstract

“…One example is anthropogenic loss of the Greenland Ice Sheet (GIS), which has not yet led to detectable SPNA freshening [61,62]. Nevertheless, uncertainty exists on the fate of GIS meltwater because it depends on circulation model resolution, and how the GIS discharge is parametrized [62][63][64]. These processes are not accurately represented in the ECCOv4r4 state estimate.…”

Section: Sub-polar North Atlantic Freshwater Variations and Mechanismsmentioning

confidence: 99%

Arctic freshwater impact on the Atlantic Meridional Overturning Circulation: status and prospects

Haine,

Siddiqui,

Jiang

2023

Phil. Trans. R. Soc. A.

View full text Add to dashboard Cite

Arguably, the most conspicuous evidence for anthropogenic climate change lies in the Arctic Ocean. For example, the summer-time Arctic sea ice extent has declined over the last 40 years and the Arctic Ocean freshwater storage has increased over the last 30 years. Coupled climate models project that this extra freshwater will pass Greenland to enter the sub-polar North Atlantic Ocean (SPNA) in the coming decades. Coupled climate models also project that the Atlantic Meridional Overturning Circulation (AMOC) will weaken in the twenty-first century, associated with SPNA buoyancy increases. Yet, it remains unclear when the Arctic anthropogenic freshening signal will be detected in the SPNA, or what form the signal will take. Therefore, this article reviews and synthesizes the state of knowledge on Arctic Ocean and SPNA salinity variations and their causes. This article focuses on the export processes in data-constrained ocean circulation model hindcasts. One challenge is to quantify and understand the relative importance of different competing processes. This article also discusses the prospects to detect the emergence of Arctic anthropogenic freshening and the likely impacts on the AMOC. For this issue, the challenge is to distinguish anthropogenic signals from natural variability. This article is part of a discussion meeting issue ‘Atlantic overturning: new observations and challenges’.

show abstract

An Improved and Observationally‐Constrained Melt Rate Parameterization for Vertical Ice Fronts of Marine Terminating Glaciers

Cited by 18 publications

References 45 publications

Improved Parameterizations of Vertical Ice‐Ocean Boundary Layers and Melt Rates

Improved Parameterizations of Vertical Ice‐Ocean Boundary Layers and Melt Rates

Persistent overcut regions dominate the terminus morphology of a rapidly melting tidewater glacier

Arctic freshwater impact on the Atlantic Meridional Overturning Circulation: status and prospects

Contact Info

Product

Resources

About