USAP-DC

{"dp_type": "Project", "free_text": "Glacier-Ocean Boundary Layer"}

[{"awards": "2434858 Washam, Peter", "bounds_geometry": "POLYGON((-0.2 -70.3,-0.16 -70.3,-0.12 -70.3,-0.08 -70.3,-0.04 -70.3,0 -70.3,0.04 -70.3,0.08 -70.3,0.12 -70.3,0.16 -70.3,0.2 -70.3,0.2 -70.31,0.2 -70.32,0.2 -70.33,0.2 -70.34,0.2 -70.35,0.2 -70.36,0.2 -70.37,0.2 -70.38000000000001,0.2 -70.39,0.2 -70.4,0.16 -70.4,0.12 -70.4,0.08 -70.4,0.04 -70.4,0 -70.4,-0.04 -70.4,-0.08 -70.4,-0.12 -70.4,-0.16 -70.4,-0.2 -70.4,-0.2 -70.39,-0.2 -70.38000000000001,-0.2 -70.37,-0.2 -70.36,-0.2 -70.35,-0.2 -70.34,-0.2 -70.33,-0.2 -70.32,-0.2 -70.31,-0.2 -70.3))", "dataset_titles": null, "datasets": null, "date_created": "Wed, 10 Sep 2025 00:00:00 GMT", "description": "Ice shelves fringe most of Antarctica\u2019s coastline where the ice sheet detaches from the underlying bed and enters the ocean. These expansive floating bodies of ice provide an important bottleneck on seaward flow of ice from the Antarctic ice sheet and sea level rise through their resistive buttressing forces. The ocean melts ice shelves from below, which removes their mass and influences their buttressing capacity. Local regions of thin ice, referred to as channels and crevasses, form in the base of ice shelves from ocean-driven melting and strain-driven cracking. These features represent potential weak points in the ice that are particularly susceptible to increased melting if ocean temperatures rise, because of their high slope angles. Improving understanding of the processes that determine the rate of melting along ice bases of varying slopes has global societal and environmental implications, as it stands to reduce uncertainties in projected sea level rise. This project will study variable melting along sloping ice using a novel field data set collected in a channel etched into the base of Fimbul Ice Shelf, Antarctica in 2024. Results from this project will provide a baseline for how sloped bases of ice shelves melt, which can be used to improve parameterizations of this process in large-scale models responsible for sea level rise projections. This study focuses on ocean-driven melting along sloping sidewalls of local thin points in ice shelves, such as basal channels or basal crevasses. These features are particularly sensitive to oceanographic forcing, as they exhibit high slopes that can melt rapidly when exposed to warm ocean conditions. If this melting is strong enough, then it can erode features to the point that they become unstable, resulting in full-thickness fractures that promote iceberg calving and ice shelf destabilization. Notably, the upstream effect of ice shelf changes related to oceanographic forcing is a major source of uncertainty in projections of Antarctica\u2019s contribution to future global sea level rise, which could amount to 53 cm by 2100. The primary objective of this project is to make significant improvements to the understanding of how the ocean melts sloped ice shelf basal topography under various forcing. The secondary objective is to understand how ice topography then evolves over time from this ocean forcing. The principal study location is Fimbul Ice Shelf, Antarctica, where in situ data was collected with the Icefin underwater vehicle and other instrumentation in January 2024, as part of an international collaboration with the United Kingdom and Norway. Results from this study will be placed into the larger context of ice shelf melting around Antarctica by comparing with previous data collected with Icefin in various oceanographic settings. The goal of this effort is to better constrain the poorly understood coupled ice-ocean processes that control melting along variable slopes. The Icefin data will be analyzed alongside data from surface-based ice penetrating radar, remote sensing, long-term oceanographic mooring, and output from the Finite-Volume Community Ocean Model. This award reflects NSF\u0027\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027\u0027s intellectual merit and broader impacts review criteria.", "east": 0.2, "geometry": "POINT(0 -70.35)", "instruments": null, "is_usap_dc": true, "keywords": "OCEAN CURRENTS; Subglacial Observations; Ocean Circulation Model; Observation Data; GLACIERS/ICE SHEETS; East Antarctica; GLACIER MASS BALANCE/ICE SHEET MASS BALANCE; Ice Shelf; SALINITY/DENSITY; Ice Shelf Meltwater; Antarctica; Subglacial Topography; OCEAN TEMPERATURE; Dronning Maud Land; WATER MASSES; Glacier-Ocean Boundary Layer; GLACIER TOPOGRAPHY/ICE SHEET TOPOGRAPHY", "locations": "Dronning Maud Land; Antarctica; East Antarctica", "north": -70.3, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Washam, Peter; Schmidt, Britney", "platforms": null, "repositories": null, "science_programs": null, "south": -70.4, "title": "SLOPES: The role of basal slopes in ice shelf melting", "uid": "p0010540", "west": -0.2}, {"awards": "2152742 Schmidt, Britney", "bounds_geometry": "POLYGON((-152.29 -82.46,-152.289 -82.46,-152.28799999999998 -82.46,-152.287 -82.46,-152.286 -82.46,-152.285 -82.46,-152.284 -82.46,-152.283 -82.46,-152.282 -82.46,-152.281 -82.46,-152.28 -82.46,-152.28 -82.461,-152.28 -82.46199999999999,-152.28 -82.463,-152.28 -82.464,-152.28 -82.465,-152.28 -82.466,-152.28 -82.467,-152.28 -82.468,-152.28 -82.469,-152.28 -82.47,-152.281 -82.47,-152.282 -82.47,-152.283 -82.47,-152.284 -82.47,-152.285 -82.47,-152.286 -82.47,-152.287 -82.47,-152.28799999999998 -82.47,-152.289 -82.47,-152.29 -82.47,-152.29 -82.469,-152.29 -82.468,-152.29 -82.467,-152.29 -82.466,-152.29 -82.465,-152.29 -82.464,-152.29 -82.463,-152.29 -82.46199999999999,-152.29 -82.461,-152.29 -82.46))", "dataset_titles": "Icefin and hydrographic profile data, and noble gas water samples from the Kamb Ice Stream subglacial channel cavity ", "datasets": [{"dataset_uid": "601975", "doi": "10.15784/601975", "keywords": "Antarctica; Bathymetry; Cryosphere; Glacial Volcanism; Ice Shelf; Ice-Shelf Basal Melting; Noble Gas; Noble Gas Isotopes; Physical Oceanography; Ross Ice Shelf; Subglacial Hydrology; Temperature; Video Data", "people": "Schmidt, Britney; Washam, Peter", "repository": "USAP-DC", "science_program": null, "title": "Icefin and hydrographic profile data, and noble gas water samples from the Kamb Ice Stream subglacial channel cavity ", "url": "https://www.usap-dc.org/view/dataset/601975"}], "date_created": "Fri, 29 Aug 2025 00:00:00 GMT", "description": "This project, part of an international collaboration with scientists from New Zealand, will conduct in situ exploration of an active subglacial channel in Antarctica. It will deploy the Icefin robotic vehicle through a borehole in the Kamb Ice Stream in West Antarctica to provide new three-dimensional context on the processes occurring at the base of the ice stream where it meets the ocean and goes afloat. Kamb Ice Stream transitioned from active to stagnant roughly 160 years ago. With the new perspectives offered by Icefin, the international collaboration aims to integrate remote sensing, geophysical, and oceanographic data to improve understanding of how subglacial channels mediate the exchange between the ice and hydrology of the grounded glacier upstream with the ice-shelf and sub-ice-shelf ocean circulation under the downstream floating section. The team aims to gain new perspectives on the dynamics of ice streams to constrain projections of future behavior in a warming world. The uniquely capable underwater vehicle Icefin will be deployed in collaboration with Antarctica New Zealand who are establishing a camp at the grounding-zone channel at Kamb Ice Stream. Icefin carries onboard sensors that map the physical structure of the ice, seafloor, and water column. Icefin observations will test two key hypotheses: that transitions in the hydrology of the ice stream caused stagnation that is recorded in the channel, and that channel evolution is driven by ice-ocean interactions caused by subglacial water interacting with the inflow of ocean water. In combination with sediment cores, oceanographic moorings, and geophysical surveys conducted by New Zealand colleagues, these data should enable a better understanding of connections between subglacial outflow and the ocean, and how these interactions have evolved over time as the channel has grown. The subglacial channel will be mapped in high resolution along an approximately 3-4 km section up and downstream of the borehole. The collected data will be analyzed to produce reconstructions of the ice, ocean, and seafloor, and then modeling and data interpretation will build a multi-parameter three-dimensional context for the channel. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": -152.28, "geometry": "POINT(-152.285 -82.465)", "instruments": null, "is_usap_dc": true, "keywords": "GLACIERS/ICE SHEETS; Ice Shelf; Subglacial Hydrology; Siple Coast; HEAT FLUX; Hot Water Drill; GLACIER MASS BALANCE/ICE SHEET MASS BALANCE; WATER MASSES; Atmosphere Exchange; Kamb Ice Stream; Glacier-Ocean Boundary Layer; Glacial Volcanism; Mantle Melting; OCEAN CURRENTS; Ross Ice Shelf", "locations": "Kamb Ice Stream; Ross Ice Shelf; Siple Coast", "north": -82.46, "nsf_funding_programs": "Antarctic Glaciology", "paleo_time": null, "persons": "Schmidt, Britney; Washam, Peter", "platforms": null, "repo": "USAP-DC", "repositories": "USAP-DC", "science_programs": null, "south": -82.47, "title": "Unravelling the Role of Subglacial Channels in Ice Stream Evolution", "uid": "p0010535", "west": -152.29}, {"awards": "2146791 Lai, Chung Kei Chris", "bounds_geometry": null, "dataset_titles": null, "datasets": null, "date_created": "Fri, 06 May 2022 00:00:00 GMT", "description": "Melt from the Greenland and Antarctic ice sheets is increasingly contributing to sea-level rise. This ice sheet mass loss is primarily driven by the thinning, retreat, and acceleration of glaciers in contact with the ocean. Observations from the field and satellites indicate that glaciers are sensitive to changes at the ice-ocean interface and that the increase in submarine melting is likely to be driven by the discharge of meltwater from underneath the glacier known as subglacial meltwater plumes. The melting of glacier ice also directly adds a large volume of freshwater into the ocean, potentially causing significant changes in the circulation of ocean waters that regulate global heat transport, making ice-ocean interactions an important potential factor in climate change and variability. The ability to predict, and hence adequately respond to, climate change and sea-level rise therefore depends on our knowledge of the small-scale processes occurring in the vicinity of subglacial meltwater plumes at the ice-ocean interface. Currently, understanding of the underlying physics is incomplete; for example, different models of glacier-ocean interaction could yield melting rates that vary over a factor of five for the same heat supply from the ocean. It is then very difficult to assess the reliability of predictive models. This project will use comprehensive laboratory experiments to study how the melt rates of glaciers in the vicinity of plumes are affected by the ice roughness, ice geometry, ocean turbulence, and ocean density stratification at the ice-ocean interface. These experiments will then be used to develop new and improved predictive models of ice-sheet melting by the ocean. This project builds bridges between modern experimental fluid mechanics and glaciology with the goal of leading to advances in both fields. As a part of this work, two graduate students will receive interdisciplinary training and each year two undergraduate students will be trained in experimental fluid mechanics to assist in this work and develop their own research projects. This project consists of a comprehensive experimental program designed for studying the melt rates of glacier ice under the combined influences of (1) turbulence occurring near and at the ice-ocean interface, (2) density stratification in the ambient water column, (3) irregularities in the bottom topology of an ice shelf, and (4) differing spatial distributions of multiple meltwater plumes. The objective of the experiments is to obtain high-resolution data of the velocity, density, and temperature near/at the ice-ocean interface, which will then be used to improve understanding of melt processes down to scales of millimeters, and to devise new, more robust numerical models of glacier evolution and sea-level rise. Specially, laser-based, optical techniques in experimental fluid mechanics (particle image velocity and laser-induced fluorescence) will be used to gather the data, and the experiments will be conducted using refractive-index matching techniques to eliminate changes in refractive indices that could otherwise bias the measurements. The experiments will be run inside a climate-controlled cold room to mimic field conditions (ocean temperature from 0-10 degrees C). The project will use 3D-printing to create different casting molds for making ice blocks with different types of roughness. The goal is to investigate how ice melt rate changes as a function of the properties of the plume, the ambient ocean water, and the geometric properties of the ice interface. Based on the experimental findings, this project will develop and test a new integral-plume-model coupled to a regional circulation model (MITgcm) that can be used to predict the effects of glacial melt on ocean circulation and sea-level rise. This award reflects NSF\u0027s statutory mission and has been deemed worthy of support through evaluation using the Foundation\u0027s intellectual merit and broader impacts review criteria.", "east": null, "geometry": null, "instruments": null, "is_usap_dc": true, "keywords": "Glacier-Ocean Boundary Layer; Alaska; USAP-DC; USA/NSF; ABLATION ZONES/ACCUMULATION ZONES; GLACIERS; AMD; Amd/Us; Antarctica; LABORATORY", "locations": "Antarctica; Alaska", "north": null, "nsf_funding_programs": "Antarctic Glaciology; Antarctic Ocean and Atmospheric Sciences", "paleo_time": null, "persons": "Lai, Chung; Robel, Alexander", "platforms": "OTHER \u003e PHYSICAL MODELS \u003e LABORATORY", "repositories": null, "science_programs": null, "south": null, "title": "Revising Models of the Glacier-Ocean Boundary Layer with Novel Laboratory Experiments ", "uid": "p0010317", "west": null}]

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