Observed Seasonal Evolution of the Antarctic Slope Current System at the Coast of Dronning Maud Land, East Antarctica

Lauber, Julius; Steur, Laura de; Hattermann, Tore; Darelius, Elin

doi:10.5194/egusphere-egu23-12791

Cited by 4 publications

(6 citation statements)

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“…The DML mooring data are available at https://doi.org/10.21334/npolar.2023.45d176be (Lauber, de Steur, et al., 2024). The sub‐ice‐shelf mooring data are available at https://doi.org/10.21334/npolar.2023.4a6c36f5 (Lauber, de Steur, et al., 2023).…”

Section: Data Availability Statementmentioning

confidence: 99%

“…The sub‐ice‐shelf mooring data are available at https://doi.org/10.21334/npolar.2023.4a6c36f5 (Lauber, de Steur, et al., 2023). The CTD section from Figure 1b is available at https://doi.org/10.21334/npolar.2023.b1504a66 (Lauber, Hattermann, et al., 2024). The H18 climatology is available at https://doi.org/10.1594/PANGAEA.893199 (Hattermann & Rohardt, 2018).…”

Section: Data Availability Statementmentioning

confidence: 99%

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Observed Seasonal Evolution of the Antarctic Slope Current System off the Coast of Dronning Maud Land, East Antarctica

Lauber,

de Steur,

Hattermann

et al. 2024

JGR Oceans

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The access of heat to the Antarctic ice shelf cavities is regulated by the Antarctic Slope Front, separating relatively warm offshore water masses from cold water masses on the continental slope and inside the cavity. Previous observational studies along the East Antarctic continental slope have identified the drivers and variability of the front and the associated current, but a complete description of their seasonal cycle is currently lacking. In this study, we utilize two years (2019–2020) of observations from two oceanographic moorings east of the prime meridian to further detail the slope front and current seasonality. In combination with climatological hydrography and satellite‐derived surface velocity, we identify processes that explain the hydrographic variability observed at the moorings. These processes include (a) an offshore spreading of seasonally formed Antarctic Surface Water, resulting in a lag in salinity and thermocline depth seasonality toward deeper isobaths, and (b) the crucial role of buoyancy fluxes from sea ice melt and formation for the baroclinic seasonal cycle. Finally, data from two sub‐ice‐shelf moorings below Fimbulisen show that flow at the main sill into the cavity seasonally coincides with a weaker slope current in spring/summer. The flow is directed out of the cavity in autumn/winter when the slope current is strongest. The refined description of the variability of the slope current and front contributes to a more complete understanding of processes important for ice‐shelf‐ocean interactions in East Antarctica.

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Section: Data Availability Statementmentioning

confidence: 99%

Section: Data Availability Statementmentioning

confidence: 99%

Observed Seasonal Evolution of the Antarctic Slope Current System off the Coast of Dronning Maud Land, East Antarctica

Lauber,

de Steur,

Hattermann

et al. 2024

JGR Oceans

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show abstract

Section: Appendix A: Processing Of Oxygen Datamentioning

confidence: 99%

Hydrography and circulation below Fimbulisen Ice Shelf, East Antarctica, from 12 years of moored observations

Lauber,

Hattermann,

de Steur

et al. 2024

Preprint

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Abstract. Future mass loss from the East Antarctic Ice Sheet represents a major uncertainty in projections of future sea level rise. Recent studies have highlighted the potential vulnerability of the East Antarctic Ice Sheet to atmospheric and oceanic changes, but long-term observations inside the ice shelf cavities are rare, especially in East Antarctica. Here, we present new insights from observations from three oceanic moorings below Fimbulisen Ice Shelf from 2009 to 2021. We examine the characteristics of Warm Deep Water (WDW) intrusions across a sill connecting the cavity to the open ocean, and investigate seasonal variability of the circulation and water masses inside the cavity. In autumn, solar-heated, buoyant Antarctic Surface Water (ASW) reaches below the 350 m deep central part of the ice shelf, separating colder Ice Shelf Water from the ice base and affecting the cavity circulation on seasonal timescales. At depth, the occurrence of WDW is associated with the advection of cyclonic eddies across the sill into the cavity. These eddies reach up to the ice base. The warm intrusions occur favorably from January to March and from September to November, and traces of WDW-derived meltwater close to the ice base imply an overturning of these warm intrusions inside the cavity. We suggest that both the offshore thermocline depth and interactions of the Antarctic Slope Current with the ice shelf topography over the continental slope cause this timing. Our findings provide a better understanding of the interplay between shallow ASW and deep WDW inflows for basal melting at Fimbulisen, with implications for the potential vulnerability of the ice shelf to climate change.

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Section: Appendix A: Processing Of Oxygen Datamentioning

confidence: 99%

“…The DML mooring data are available at https://doi.org/10.21334/npolar.2023.45d176be (Lauber et al, 2024a). The CTD data from the Troll Transect 2020/21 cruise are available at https://doi.org/10.21334/npolar.2023.b1504a66 (Lauber et al, 2024b). The hydrographic climatology at 17 • W is available at https://doi.org/10.1594/PANGAEA.893199 (Hattermann and Rohardt, 2018).…”

Section: Appendix A: Processing Of Oxygen Datamentioning

confidence: 99%

Comment on egusphere-2024-904

Padman

2024

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Observed Seasonal Evolution of the Antarctic Slope Current System at the Coast of Dronning Maud Land, East Antarctica

Cited by 4 publications

References 0 publications

Observed Seasonal Evolution of the Antarctic Slope Current System off the Coast of Dronning Maud Land, East Antarctica

Observed Seasonal Evolution of the Antarctic Slope Current System off the Coast of Dronning Maud Land, East Antarctica

Hydrography and circulation below Fimbulisen Ice Shelf, East Antarctica, from 12 years of moored observations

Comment on egusphere-2024-904

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