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Ocean heat transport to Antarctic ice shelves
Ocean heat transport to Antarctic ice shelves
By providing a buffer between the Antarctic Ice Sheet and warm lower latitude waters, Antarctica's continental shelf region plays a key role the regulation of global sea-level and climate. A variety of physical processes occurring on and off the continental shelf influence the transport of ocean heat from the open Southern Ocean towards Antarctica's floating ice shelves. I'm interested in improving our understanding of these processes and their influence on ice sheet melt.
Related Works:
image: simulation output (LLC270-SO, used in Moorman et al 2025) showing the temperature of waters around Antarctica at 500 m depth. Warm waters are found off the continental shelf everywhere but only stray towards the coast (where they rapidly melt ice shelves) in some regions. What processes hold this warm water at bay?
The Antarctic coastal ocean heat budget is dominated by heat loss to land ice melt (in press at Science Advances)
Ross Gyre variability modulates oceanic heat supply toward the West Antarctic continental shelf (Communications Earth & Environment, 2023) (First author: Channing Prend)
Response of Antarctic ocean circulation to increased meltwater (Thesis, 2020)
image: simulation output (LLC270-SO, used in Moorman et al 2025) showing the temperature of waters around Antarctica at 500 m depth. Warm waters are found off the continental shelf everywhere but only stray towards the coast (where they rapidly melt ice shelves) in some regions. What processes hold this warm water at bay?
Antarctic coastal polynyas
Antarctic coastal polynyas
Antarctic latent heat coastal polynyas are small geographical regions with outsized roles in the global climate. Polynyas are gaps in sea ice cover ranging in size from 10's to 10,000's of km across and are found across Arctic and Antarctic environments. They can arise from the local melting of sea ice by anomalously warm seawater ("sensible heat polynyas") or from the mechanical removal of sea ice, for example by winds ("latent heat polynyas"). Latent heat polynyas are scattered along the coast of Antarctica due to strong offshore winds. These polynyas are sites of intensive sea ice formation, which is associated with ocean heat loss and salinification by brine rejection, as frozen ice is quickly swept away, exposing more ocean water is exposed to the freezing atmosphere. As extreme localized sites of heat, freshwater, and thus buoyancy loss, these polynyas can influence both local and larger scale circulation patterns and modulate the temperatures of ocean waters accessing ice shelves. I'm interested in better understanding polynya dynamics and projecting changes in their behavior under climate change.
Related Works:
Supercooled Southern Ocean waters (Geophysical Research Letters, 2020) [First author: Alexander Haumann)
The three-dimensional overturning of the West Antarctic continental shelf (in prep) [First author: Andrew Thompson]
image: satellite imagery of the Ross Sea polynya, source. Grounded ice is on the left, sea ice on the upper right and center, and ice shelf on the lower right corner.
Antarctic Bottom Water formation & transport
Antarctic Bottom Water formation & transport
Antarctic Bottom Water is a cold, dense water-mass that fills the majority of the abyssal oceans. Its formation and transport are critical to the closure of the southern, abyssal arm of the meridional overturning circulation and thus have a profound role in abyssal ventilation and the global circulation of heat and carbon. I'm interested in better understanding these processes and investigating how the climate system responds to shifts in Antarctic Bottom Water production and properties.
Related Works:
Response of Antarctic ocean circulation to increased meltwater (Thesis, 2020)
The three-dimensional overturning of the West Antarctic continental shelf (in prep) [First author: Andrew Thompson]
image: the formation of dense shelf waters via surface processes on the continental shelf (red shading, south of the black contour) and abyssal export pathways of shelf sourced dense waters (green shading, north of the black contour) as captured by a high (0.1º) resolution ocean--sea-ice model, ACCESS-OM2-01. For details see Moorman et al (2020).
I have explored these and related topics with the following research tools
I have explored these and related topics with the following research tools
GENERAL CIRCULATION MODELS (GCMs)
GCMs attempt to represent the full suite of fluid dynamics and thermodynamics dictating weather and climate on a grid structure that typically looks like the real Earth (or a part of it). These are the types of models used for weather and climate forecasting.
I have mostly used GCMs that explicitly model the behavior of the oceans, sea ice, and (sometimes, in a simplified way) ice shelves, while prescribing the behavior of the atmosphere, treating it as a source of "forcing". I have worked both with global scale GCMs and regional GCMs across a range of spatial resolutions and capabilities.
Whilst GCMs are a powerful tool, their causal complexity and high degree of parameterization presents risks when relied on as a sole source of information, and I prefer to combine their use with theory and observations.
Relevant works:
The Antarctic coastal ocean heat [...] (press)
The three-dimensional overturning [...] (prep)
Ross Gyre variability [...] (Comms Earth & Env, 2023) (First author: Channing Prend)
image: cube sphere (left) and LLC (right) grids, credit
IN-SITU OCEAN MEASUREMENTS
In an era when many scientists manage a glut of data, Antarctic coastal environments remain under-sampled in both space and time due to general inaccessibility and hostile equipment conditions. The warm coastal waters driving accelerated West Antarctic Ice Sheet melt were first observed with ship deployed sensors as recently as 1994, and observing variations in this warm water pool remains challenging and expensive, but essential for predicting sea level.
In my work I have benefitted immensely from the open access publication of hydrographic profiles (typically ocean temperature and salinity) collected by a community of seagoing scientists from a handful of Antarctic ready research vessels. Gaps between infrequent ship expeditions are then (somewhat) filled by furry friends; the inclusion of temperature and salinity sensors on seal tags typically used for ecological studies has revolutionized our coverage of the Antarctic margins.
Relevant works:
Ross Gyre variability [...] (Comms Earth & Env, 2023) (First author: Channing Prend)
Supercooled Southern Ocean [...] (GRL, 2020) (First author: Alexander Haumann)
image: instrumented seal, credit Dan Costa
LOW DIMENSIONAL (THEORETICAL) MODELS
I find that simplified low dimensional models of specific physical processes can be very useful when interpreting complex observations and GCM results. Simple models can be an interesting exploratory space or a crucial causality sanity check on mechanisms suggested by complex data. Low dimensional models can also pave the way for parameterization methods that may be integrated into complex models.
In my work I have particularly enjoyed adapting theoretical frameworks developed to understand the global overturning circulation to regional problems of the Antarctic coast.
Relevant works:
The three-dimensional overturning [...] (prep)
image: sketch a low dimensional model described in Moorman et al (2023).
...I have also dabbled in the use of data from satellite supported instruments and anticipate more work in that space.
...I have also dabbled in the use of data from satellite supported instruments and anticipate more work in that space.
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