In this session we aim to bring together the most up to date work on ice-ocean interactions across all latitudes, covering in-situ observations, remote-sensing, modelling and theory. We seek a bi-directional perspective, investigating both the impact of the ocean on the cryosphere and vice-versa, from small scale physical processes to global impacts. Topics for submission include, but are not limited to: coupled ice-ocean models, ice shelf cavity and fjord circulation, ice melange, subglacial meltwater plumes, basal and submarine melting and freshwater fluxes into the ocean. New observational datasets and methodologies are encouraged.
We welcome and encourage submissions from groups who are underrepresented in the cryosphere community and will endeavour to provide reasonable adjustments to any presenter who requires them.
Orals: Mon, 4 May, 14:00–15:45 | Room 1.34
The rapid ice loss from the Amundsen Sea sector of West Antarctica is a major contributor to global sea-level rise, and is driven by changes in ocean melting. In this study we use high-resolution ocean simulations to understand the mechanisms controlling ice-shelf melting in the eastern Amundsen Sea. Melting is focussed on four ‘hot spots’ of melting of the deep ice where the main glacier trunks cross the grounding line. Secondary areas of elevated melting occur beneath the associated buoyant meltwater plumes, which are guided by ice topography and Coriolis force. The simulations are then used to test simple local parameterisations of melting. The best parameterisation expresses melt rate as a simple function of ocean temperature to the power 3/2, ice slope to the power 1/2, and tapered to zero near the grounding line. This matches the simulated melting with a spatial correlation of r2=0.65, capturing deep melting near the grounding line but omitting melting by the buoyant plumes. This parameterisation also broadly captures the strong melting feedbacks that appear when the model is applied to possible future ice geometries. This leads us to speculate that simple local melting parameterisations may be sufficient in ice sheet forecasts wherever ice shelf buttressing is focussed near the grounding line (such as Thwaites Glacier), but may be inadequate in regions where melting beneath shear margins controls buttressing (such as Pine Island Glacier).
How to cite: Holland, P., Jenkins, A., Bett, D., Bevan, S., and Luckman, A.: Modelling and Parameterisation of Ice-Shelf Melting in the Amundsen Sea, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-2856, https://doi.org/10.5194/egusphere-egu26-2856, 2026.
How to cite: Reed, B., De Rydt, J., Naughten, K., and Goldberg, D.: Calibration of a coupled ice-ocean model using observations of ice dynamics and basal melt in West Antarctica, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3797, https://doi.org/10.5194/egusphere-egu26-3797, 2026.
The ocean-driven melting of ice shelves is a key impact on ice shelf mass loss and on the stability of the Antarctic ice sheet. However, knowledge is incomplete on the impact of ocean processes on the basal melting of ice shelves, in particular the effects of submesoscale processes. Inspired by recent observations of an eddy beneath an ice tongue (Hancock et al., 2025), we investigate a series of simulations to better understand the effect of eddies on the localised melting of ice shelves. Here, we examine submesoscale eddies beneath an ice shelf using large-eddy simulations that resolve all but the smallest scales of turbulence. In order to resolve the thin mm-scale layers immediately below the ice, the domain size is limited and the eddies are scaled down to be metres in size. The dynamical regime in which these simulations operate is relevant for the ocean application, hence we can relate our simulations to observations and results from large-scale ocean models. We initialise our simulations with a salinity front beneath an ice shelf, with different chosen temperature profiles to match cold and warm ice shelf cavities. Once the simulations are initiated, the front breaks into submesoscale eddies. Our results show that anticyclonic eddies enhance the ice melting by upwelling warm underlying waters. In contrast, cyclonic eddies moderate the melting by downwelling cool meltwater. Our simulated results compare favourably with the existing observations and the application to other ocean regions is also discussed.
How to cite: Vreugdenhil, C., Gui, W., Gayen, B., and Bhadouriya, A.: The impact of submesoscale ocean eddies on the basal melting of ice shelves using high-resolution simulations, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-16663, https://doi.org/10.5194/egusphere-egu26-16663, 2026.
How to cite: Neufeld, J., Conley, R., and Holland, P.: Quantifying melt rates in Antarctic grounding zones using flexural inversion, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-21154, https://doi.org/10.5194/egusphere-egu26-21154, 2026.
Wave–ice interactions are widely recognised as one of several mechanisms contributing to ice-shelf front retreat. However, their role at small spatial and temporal scales remains difficult to quantify, particularly under breaking-wave conditions. Here, we investigate wave-induced erosion at the ice–ocean interface by combining satellite observations, laboratory experiments, and simplified, scale-aware modelling.
Ice-front retreat during the austral summer of 2024 is analysed using Sentinel-1 SAR imagery. Multiple coastline-tracking methods are applied to quantify the spatial and temporal variability of the ice front. The observations reveal periodic collapse events that tend to be temporally synchronised with elevated wave activity. This points to a strong link between wave forcing and short-term ice-front instability.
To interpret these observations, we extend classical wave-induced melting formulations by introducing a first-order, breaking-aware modelling procedure. Wave shoaling and depth-limited breaking are accounted for by tracking the evolution of wave height with water depth and by using the near-breaking horizontal particle velocity as the effective velocity scale driving heat transfer at the ice–water interface. This simple approach captures the enhancement of wave-induced erosion associated with irregular and incipiently breaking waves, while remaining computationally efficient.
The formulation is first evaluated using small-scale laboratory experiments conducted at the University of Caen, where harmonic, non-breaking waves interact with an ice cube. In this controlled experiment, measured erosion rates agree well with theoretical predictions, confirming the validity of classical approaches when wave breaking is absent. When applied to field conditions at Fimbulisen, however, the breaking-aware formulation substantially increases predicted erosion rates relative to classical theory but still systematically underestimates observed retreat. The remaining discrepancy points to unresolved turbulence processes associated with fully developed breaking and motivates the need for more advanced theoretical and experimental treatment of wave-breaking-induced mixing at the ice–ocean interface.
How to cite: Lu, W., Mouaze, D., Ghadimi, B., Font, M., Lambert, R., Jubair, S., Wendt, L., Goodwin, H., Moholdt, G., Lubbad, R., and Løset, S.: Wave-induced erosion at ice-shelf fronts under irregular and breaking-wave conditions, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-12063, https://doi.org/10.5194/egusphere-egu26-12063, 2026.
Grounding lines are flux gates through which ice discharges into the ocean. Their position reflects ice sheet stability, retreating landward or advancing seaward in response to changes in melting and accumulation, while also exhibiting short-term motion driven by tidal flexure of floating ice. Grounding lines derived from Differential Interferometric SAR (DInSAR) phase are generally regarded as the most accurate [1]. However, most existing datasets lack formal uncertainty estimates, even though grounding line errors directly propagate into ice discharge calculations and can substantially bias estimates of ice mass loss and sea level rise [1]. A further limitation is that DInSAR grounding lines are derived from interferograms combining three or four SAR acquisitions, such that each estimated position represents a superposition of multiple tidal states, complicating the attribution of observed displacements to specific tidal forcing.
We have developed a framework to obtain grounding line positions together with Bayesian estimates of positional uncertainty. Based on this, we generated a dense time series of grounding lines for the Larsen C Ice Shelf spanning 2019–2021, derived from Sentinel-1 line-of-sight (LOS) offsets at a temporal sampling of 6 days. The LOS offsets are part of the operational processing pipeline used by ENVEO IT to produce monthly and annual Sentinel-1 ice-velocity maps, and were computed by tracking features between consecutive SAR backscatter images [2], [3]. Grounding line positions were estimated by fitting the LOS offsets to a one-dimensional elastic beam model [4] and performing Bayesian inversion using the cross entropy based importance sampling for Bayesian updating (CEBU) algorithm [5], which allows the incorporation of external datasets as priors on model parameters. Additionally, the estimated error of the range offsets were explicitly accounted for in the inversion. The resulting dataset provides a dense time series of grounding lines which have a mean distance of 348.07 m from Sentinel-1 DInSAR grounding lines. Because the dataset is derived from SAR backscatter rather than interferometric phase, it is robust to coherence loss and can be used to fill gaps in DInSAR grounding line products over fast-flowing outlet glaciers and ice streams.
References
[1] E. Rignot, J. Mouginot, and B. Scheuchl, “Antarctic grounding line mapping from differential satellite radar interferometry: GROUNDING LINE OF ANTARCTICA,” Geophysical Research Letters, vol. 38, no. 10, 2011
[2] T. Nagler, H. Rott, M. Hetzenecker, J. Wuite, and P. Potin, “The sentinel-1 mission: New opportunities for ice sheet observations,” Remote Sensing, vol. 7, no. 7, pp. 9371–9389, 2015.
[3] J. Wuite, T. Nagler, M. Hetzenecker, and H. Rott, “Ten years of polar ice velocity mapping using Copernicus Sentinel-1,” Remote Sensing of Environment, vol. 332, p. 115 092, Jan. 2026
[4] G. Holdsworth, “Flexure of a Floating Ice Tongue,” Journal of Glaciology, vol. 8, no. 54, pp. 385–397, 1969, 1727-5652
[5] M. Engel, O. Kanjilal, I. Papaioannou, and D. Straub, “Bayesian updating and marginal likelihood estimation by cross entropy based importance sampling,” Journal of Computational Physics, vol. 473, p. 111 746, Jan. 2023
How to cite: Ramanath Tarekere, S., Engel, M., Krieger, L., Wuite, J., Floricioiu, D., and Körner, M.: Spatially and Temporally Dense Grounding Lines from Bayesian Inversion of Sentinel-1 Data, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-20585, https://doi.org/10.5194/egusphere-egu26-20585, 2026.
Marine-terminating glaciers in central and southeast Greenland are major contributors to Greenland’s dynamic mass loss and include several of its fastest-flowing outlet glaciers. Ice-ocean interactions have a strong control on the dynamics of marine-terminating glaciers, yet observations of region-wide glacier responses to ocean forcing remains limited. Recent dynamic changes across this sector have largely been studied at smaller spatial scales, limiting our understanding of coherent and more widespread regional scale behaviour and responses to environmental forcing.
Here, we use more than a decade of Sentinel-1 satellite observations to measure ice velocity change on 66 marine-terminating glaciers, between 2014 and 2025 and access the impact of ocean and sea-ice anomalies on glacier dynamics. We observe a widespread and pronounced speedup on ice streams in this region with synchronous acceleration beginning in 2016 and peaking around 2020. Speedup is observed on 43 of the 66 glaciers with the majority of speedup exceeding that observed in the mid 2000’s. Six glaciers more than double in speed and several ice streams reach their fastest speeds in at least two decades. This period of acceleration is followed by a widespread deceleration after 2020, although most glaciers remain faster than their pre-2016 velocities.
We investigate the impact of ocean and atmospheric forcing on the ice velocity change to better understand the drivers. Our results indicate that the timing of this region wide acceleration coincides with anomalously warm surface and subsurface ocean temperatures and a prolonged reduction in regional sea-ice concentration, suggesting that ocean driven forcing may have synchronised glacier responses.
These results show that recent ocean driven dynamic change in central and southeast Greenland has been larger and more spatially extensive than previously recognised, highlighting the susceptibility of these glaciers to rapid, synchronous change and the importance of ice-ocean interactions. The sensitivity of the region to ocean forcing shows that this marine terminating part of the Greenland ice sheet is delicately coupled with its environment and should be closely monitored in the future.
How to cite: Evans, M., Hogg, A., Surawy-Stepney, T., Wallis, B., Slater, R., and Rigby, R.: Synchronous velocity change in response to ocean forcing on marine-terminating glaciers in central- and south-eastern Greenland (2014–2025), EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-9851, https://doi.org/10.5194/egusphere-egu26-9851, 2026.
In recent decades, Greenland’s marine-terminating glaciers have retreated and accelerated, contributing significantly to global sea level rise. The presence of an ice mélange, and its associated buttressing force on a glacier terminus, has a significant impact on glacier advance and retreat. The buttressing force is modulated by the thickness of the ice mélange, which in turn is influenced by mélange melt rate, but our understanding of ice mélange melting remains limited. In particular, a quantitative understanding of how the thickness of an ice mélange impacts melt rates is lacking.
Here, we model the melting of ice mélange by the ocean using the ocean model MITgcm to simulate the water flow in the first 15km down-fjord from the calving front, focusing specifically on the relationship between the melt rate and the mélange thickness. Ice mélange is represented in the model by cuboid icebergs that are thermodynamically active, divert the fluid flow and represent a range of sizes to reflect realistic observed iceberg distributions. We find that melt rate generally increases with mélange thickness and is particularly sensitive to mélange thickness at thicknesses below approximately 100 metres. Based on these simulations, we develop a parameterisation for mélange melt rate as a function of subglacial discharge, oceanic thermal forcing and mélange thickness. We then apply this parameterisation around Greenland to the ice mélange at 27 glaciers. We estimate melt rates in the range 0.05 – 0.92 m/d, which is comparable with observational estimates, and extract the dominant factors that control glacier-to-glacier variability in mélange melt. The development of this parameterisation is a key step in advancing our understanding of the dynamics of ice mélange and enabling a representation of ice mélange in larger climate and ice sheet models.
How to cite: Jain, L., Slater, D., and Nienow, P.: Impact of ice mélange thickness on mélange melt rate in Greenland’s glacial fjords, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-14670, https://doi.org/10.5194/egusphere-egu26-14670, 2026.
The Greenland Ice Sheet loses roughly half of its mass by ice discharge at marine terminating
glaciers. Some of the largest and fastest flowing glaciers around Greenland calve kilometre-scale
icebergs into long, narrow and deep fjords. These enormous icebergs typically capsize, or “flip” into
more gravitationally stable orientations, and in doing so are thought to vigorously mix the stratified
ocean within a small region in front of the glacier front.
We investigate the effect of sudden ocean mixing events on flow within an idealised, linearly
stratified model fjord using the Oceananigans.jl nonhydrostatic model. A large fraction of the
available potential energy is rapidly converted to kinetic energy and radiates away as internal waves.
These internal waves produce pulses of elevated melt rate across the entire glacier front, with
magnitudes comparable to melt rates due to subglacial discharge plumes. On longer timescales, the
qualitative character of the response depends on the ratio of fjord width, W, to first baroclinic
Rossby deformation radius, R. Typical Greenland fjords have W/R between 0.5 and 2.0. Within this
range of W/R, our model predicts the appearance of a long-lived nearly geostrophic anticyclonic
eddy spanning the entire width of the fjord, constrained to mid-depths, in front of the glacier
terminus. This eddy drives a sustained melt anomaly at mid-depths for many days, which may
promote undercutting. We also investigate sensitivity to the horizontal extent of the region over
which the fluid is mixed, and find that increasing the mixed volume beyond some critical value
destabilises the abovementioned eddy, leading to its break up and consequently reducing the
predicted glacier melt rate.
How to cite: Tovey Garcia, O. and Wells, A.: Impacts of iceberg capsize-induced sudden ocean mixing on fjord circulation and glacier melt, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-22362, https://doi.org/10.5194/egusphere-egu26-22362, 2026.
Interactions between tidewater glaciers and fjord waters play a key role in Greenland Ice Sheet mass loss. However, many of the underlying processes remain hidden beneath the fjord surface. In particular, the coupling between subglacial meltwater discharge, plume formation, fjord circulation, ice mélange conditions, and glacier dynamics is poorly constrained due to the difficulty of obtaining temporally and spatially highly resolved observations in these environments. This lack of observations limits our ability to resolve glacier-fjord interactions, resulting in considerable uncertainties in mass loss projections.
We address this challenge using an extensive time series of terrestrial radar interferometry (TRI) observations collected at the tidewater glacier Eqalorutsit Kangilliit Sermiat in South Greenland. Using this dataset, we analyse meltwater plume activity, ice mélange conditions in the fjord, glacier motion, calving activity, and 3-dimensional fjord circulation at minute-scale temporal resolution over several weeks, presenting an integrated observational view of the glacier–fjord system, including processes occurring below the waterline.
Fjord circulation is inferred using an autonomous iceberg-tracking framework that derives 3-dimensional flow patterns from the motion of icebergs spanning a wide range of sizes. Combining trajectory data with iceberg drafts, estimated from TRI-derived elevation models, allows circulation to be resolved across different water-depth layers within the ~300 m deep fjord. These observations are evaluated alongside fjord stratification measured by CTD profiles. The results reveal a highly complex circulation that varies strongly with water depth, time, and location in the fjord. Icebergs can even move in opposite directions depending on their draft and the dominant current acting on them. These observations are consistent with modelled fjord circulation, placing the measurements within a process-based framework.
Subglacial meltwater discharge and plume dynamics are investigated using a newly developed autonomous plume-detection algorithm applied to terrestrial radar data. Temporal changes in plume surface area are combined with melt modelling and subglacial hydrological routing to estimate meltwater fluxes entering the fjord. In parallel, ice mélange conditions are quantified using time-lapse imagery and radar backscatter, providing insight into mélange rigidity, its temporal evolution, and its influence on calving and terminus dynamics. On short (subdaily) timescales, plume area does not directly reflect discharge magnitude, as ice mélange conditions strongly control whether meltwater reaches the surface. Over longer (daily) timescales, however, plume size evolution generally agrees with estimated discharge variability.
Overall, these results advance our understanding of how subglacial discharge–driven circulation influences ocean-driven melting and glacier terminus stability, with important implications for projecting Greenland Ice Sheet mass loss and assessing fjord ecosystem responses under ongoing climate change.
How to cite: Kneib-Walter, A., Slater, D., Dachauer, A., and Vieli, A.: Resolving glacier–fjord interactions using observations of 3-dimensional fjord circulation, plume activity, and glacier dynamics, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6776, https://doi.org/10.5194/egusphere-egu26-6776, 2026.
The ice shelves in the Amundsen Sea, West Antarctica, are being melted rapidly by warm Circumpolar Deep Water (CDW), causing sea-level rise. Variability in ice-shelf melting is controlled by the speed of a shelf-break undercurrent which transports CDW from the deep ocean onto the continental shelf. We study decadal variability of the undercurrent and ice-shelf melting using new regional ice-ocean model perturbation experiments. The perturbation experiments suggest that the undercurrent decadal variability is controlled by variable coastal sea-ice freshwater fluxes, these driven by winds mechanically opening and closing coastal polynyas. With the perturbation experiments we also quantify a positive feedback mechanism between the undercurrent and ice-shelf melting which is responsible for 25% of their decadal variability.
How to cite: Haigh, M., Holland, P., Caton Harrison, T., and Dutrieux, P.: Wind-driven coastal polynya variability drives decadal ice-shelf melt variability in the Amundsen Sea, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-3174, https://doi.org/10.5194/egusphere-egu26-3174, 2026.
The Antarctic Ice Sheet is losing mass, a large part of which is due to ocean melting under ice shelves. Current projections from the ISMIP6 project show a gradually warming ocean forcing in currently cold cavities, but there is a growing literature that this may not be an accurate representation of how the temperatures beneath the ice shelves will change. Instead, the cold Antarctic ice shelves – like Filchner-Ronne or Ross – are expected to experience an intrusion of warmer circumpolar deep water under strong climate forcings. This has the potential to shift the regime of the Antarctic basins from cold to warm states, leading to increased melt rates.
Here, we focus on three of the currently cold-based basins, namely Filchner-Ronne, Amery, and Ross. Using the literature of likely timings for regime shifts for each of these cavities, we investigate how an immediate temperature change at these timings compares to the gradual warming beneath the cavities modelled in the ISMIP6 simulations. We create an ocean forcing using the warm mode temperature anomalies from Nicola et al., (2025) to represent the regime change in these basins and run simulations using the numerical ice sheet models Ua and PISM, coupled with the ice sheet cavity box model PICO. Then, we compare the model outputs to simulations using the original CMIP6 ocean forcing.
Nicola, L., Reese, R., Kreuzer, M., Albrecht, T., and Winkelmann, R.: Bathymetry-constrained warm-mode melt estimates derived from analysing oceanic gateways in Antarctica, The Cryosphere, 19, 2263–2287, https://doi.org/10.5194/tc-19-2263-2025, 2025.
How to cite: Archer, R., Reese, R., Nicola, L., and Winkelmann, R.: Warm mode melt impact on ice dynamics in Antarctica, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6678, https://doi.org/10.5194/egusphere-egu26-6678, 2026.
Ocean-driven melting of ice shelves is the primary cause of ice loss in Antarctica, ultimately leading to global sea-level rise. However, there is still much uncertainty over the interactions between physical processes that lead to this ocean-driven melting, such as the role of climate-driven wind changes, increasing air temperatures and changes in freshwater fluxes, such as precipitation and ice sheet runoff. The timescales over which the ice loss will occur and the subsequent potential for sea-level rise are also areas of uncertainty in need of further investigation. At present, many ocean models that provide data to drive ice sheet models, such as those in CMIP, do not accurately represent ocean conditions around Antarctica, for example due to low model resolution or a very simplified representation of ice shelves. Ice sheet models then use empirical schemes based on remote offshore ocean temperatures to estimate the ice shelf melt from CMIP models. As such, predictions of potential sea-level rise that depend on these simulations may in turn not be accurate. Improving the representation of ocean water masses and circulation on the continental shelves and underneath the ice shelves around Antarctica would therefore be a key improvement for forcing ice sheet models that are used for predicting ice loss related sea-level rise.
We present the results from a 1/4º resolution circum-Antarctic ocean model with a representation of ice shelf cavities and ice shelf melt, run over the historical period of 1850-2020, forced with UKESM 1.2 CMIP6 outputs. These historical outputs, alongside simulations to be run with projected SSP5-8.5 forcing, will aim to provide a better representation of water masses around Antarctica to force ice sheet models. Using these, we plan to further our understanding of the physical processes that drive ocean-driven melt, and derive climate transfer functions that can bridge the gap between ice sheet models and coarse resolution general circulation models.
How to cite: Mountford, A. S., Reese, R., Jenkins, A., Bull, C. Y. S., Smith, R., Rogalla, B., and Naughten, K. A.: Towards ocean model simulations of the Southern Ocean and Antarctic ice shelf cavities forced by CMIP historical climate data, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-11623, https://doi.org/10.5194/egusphere-egu26-11623, 2026.
The melting of ice shelves into the ocean plays a major role, and is a key source of uncertainty, on sea level rise projections. Under ice shelves, meltwater moves upslope, setting up a stratified shear flow with the warmer, but critically saltier, ocean beneath, regulating the transfer of heat between ice and the ambient ocean. These stratified flows are incredibly difficult to access in situ, and so research has focussed on the use of numerical modelling, laboratory experiments and analytical models to understand these processes, each with their own assumptions, advantages and limitations.
Here we present novel direct numerical simulations that represent this basal melt process with highly resolved (sub-millimeter resolution) simulations that reveal this shear flow evolves as a unique mixed mode shear instability. Unusually, the combined input of buoyancy, and a solid boundary leads to paired Kelvin Helmholtz and Holmboe instabilities, which prove highly effective at mixing the water column. Due to the restoring effect of the boundary forcing, a cycle of growth, instability, turbulent mixing, and re-stabilisation is observed. Results for a non-rotating framework with equal diffusivities for heat and salt are contrasted to simulations with added complexity, including rotation and double-diffusive processes. These findings suggest that current ice-ocean parametrisations are fundamentally built on assumptions for stratified flow instabilities that may differ from these simulations, with potential implications for the turbulent transfer of heat and salt and ultimately basal melt rates.
How to cite: Hartharn-Evans, S., De Rydt, J., Lloyd, C., Carr, M., and Jenkins, A.: Insights into ocean mixing processes driving ice shelf melting from highly resolved simulations , EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-6816, https://doi.org/10.5194/egusphere-egu26-6816, 2026.
Conventional basal melt parameterisations for ice shelf basal melting typically calculate melt rates as a direct function of ambient ocean properties, effectively bypassing the internal physics of the ice-ocean boundary layer (IOBL). This simplification often leads to significant overestimations of melting, particularly when stable stratification is present.
The core of our framework is a set of parametric equations that computes melt rates after determining the thermal driving within the boundary layer by resolving:
- Heat transfer from the ambient ocean into the boundary layer.
- Heat transfer from the boundary layer to the ice-ocean interface.
By resolving the internal physics of the boundary layer, this framework provides a valuable tool for process studies, allowing for a deeper investigation into how different forcing mechanisms influence basal melting. We will discuss the physics behind this framework and how this framework can be developed in the future by including more physics to improve the representation of ice-ocean interactions in large-scale climate models.
How to cite: T. Pillai, J. and Jenkins, A.: Capturing Ice-Ocean Boundary Layer Physics over Dynamically Stable Pycnoclines: The Mechanics of a Parameterisation Framework for Basal Melting, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-7574, https://doi.org/10.5194/egusphere-egu26-7574, 2026.
Basal melt of marine terminating glaciers is a key uncertainty in predicting the future climate and the evolution of the Greenland Ice Sheet. Detailed observations about the distribution of melt at Greenland’s glaciers and the ocean circulation in the adjoining fjords and specifically at the ice-ocean interface, are rare, due to the remoteness of the regions of interest. Hence, we rely heavily on models to get deeper insights into the processes in the fjords, underneath the ice shelves and at the ice-ocean interface.
We present a novel Finite Element Model used to simulate the circulation in North Greenland's Sherard Osborn Fjord. Thanks to the finite elements the model can accurately represent fjord bathymetry and ice base geometry at the meter scale. A novel, symmetric, tensor-based viscosity formulation, using a residual-based method (residual viscosity), allows for high resolutions (meters) with minimal artificial viscosity and sharp gradients, while keeping computational times low.
A high resolution representation of the sill in Sherard Osborn Fjord enables a more accurate simulation of the inflow of warm Atlantic Water towards the glacier. The more realistic representation of the ice base geometry and the high resolution allows us to model the distribution of melt rate underneath the ice shelf of Ryder Glacier in great detail, which can lead to better estimates of total melt rate. Furthermore, the high resolution and novel implementation of residual viscosity in the model enables an accurate simulation of the melt water plume with sharper gradients between the plume and the ambient water due to the absence of excess artificial viscosity and diffusivity.
In addition to the high resolution 2D simulations we are currently working on a 3D simulation using realistic ice base geometry and fjord bathymetry from Ryder Glacier and Sherard Osborn Fjord.
How to cite: Wiskandt, J., Lundgren, L., Ahlkrona, J., and Nilsson, J.: A novel finite element model for simulating fjord circulation, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-10158, https://doi.org/10.5194/egusphere-egu26-10158, 2026.
During recent decades, the glaciological community has become familiar with statements in numerous papers, and high-profile reports, highlighting that ‘Greenland’s marine-terminating glaciers are retreating, accelerating and thinning’. However, while the vast majority of Greenland’s 200+ marine terminating glaciers have both retreated and thinned in recent decades, and many have certainly accelerated, the net impact of these changes on ice mass flux has been somewhat limited and extremely variable between individual glaciers. Indeed, a brief consideration of dynamic ice-flux data suggests that with the exception of a ~10% increase between 2000 and 2005, ice flux from these systems has shown minimal increase (<2%) in the two decades since the early millennial dynamic shift with the contribution from the largest 15 outlet glaciers remaining largely invariant. This observation not only brings in to question the suggestion of ubiquitous acceleration; it also raises the question that if one considers ice-flux, which is the most critical determinant for future sea-level rise, have we already or will we shortly reach peak ice flux from the Greenland Ice Sheet? It is clear that at some point, and in a corollary with ‘peak water’ in deglaciating valley glaciers, that each tidewater glacier will reach peak discharge and that this will occur prior to each glacier retreating on to land. This paper investigates in detail recent patterns of ice-flux change, both in terms of regional variability and glacier size, in order to consider the likelihood of future acceleration in ice-mass loss via solid ice-discharge from the Greenland Ice Sheet.
How to cite: Nienow, P. and Picton, H.: HAs the Greenland Ice Sheet Reached Peak Ice Discharge - HAGRID, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-19455, https://doi.org/10.5194/egusphere-egu26-19455, 2026.
