Circulation and Melting Beneath the Ross Ice Shelf

Jacobs, Stanley S.; Gordon, Arnold L.; Ardai, J. L.

doi:10.1126/science.203.4379.439

Cited by 160 publications

(103 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We calculate mixed layer depth using the density criterion of Sallée et al (2013): the shallowest depth at which the potential McMurdo Sound, in agreement with observations (Jacobs et al, 1979). A small region of dense water formation in western Prydz Bay, adjacent to the Amery Ice Shelf, is also present in both models.…”

Section: Mixed Layer Depthsupporting

confidence: 66%

Intercomparison of Antarctic ice shelf, ocean, and sea ice interactions simulated by two models

Naughten

Meißner

England

et al. 2017

Preprint

View full text Add to dashboard Cite

Abstract. An increasing number of Southern Ocean models now include Antarctic ice shelf cavities, and simulate thermodynamics at the ice-shelf/ocean interface. This adds another level of complexity to Southern Ocean simulations, as ice shelves interact directly with the ocean and indirectly with sea ice. Here we present the first published model intercomparison and evaluation of present-day ocean/sea-ice/ice-shelf interactions, as simulated by two models: a circumpolar Antarctic configuration of MetROMS (ROMS: Regional Ocean Modelling System coupled to CICE: Community Ice CodE) and the global 5 model FESOM (Finite Element Sea-ice/ice-shelf Ocean Model), where the latter is run at two different levels of horizontal resolution. From a circumpolar Antarctic perspective, we compare and evaluate simulated ice shelf basal melting and sub-ice shelf circulation, as well as sea ice properties and Southern Ocean water mass characteristics as they influence the sub-ice shelf processes. Despite their differing numerical methods, the two models produce broadly similar results, and share similar biases in many cases. Both models reproduce many key features of observations, but struggle to reproduce others, such as the 10 high melt rates observed in the small warm-cavity ice shelves of the Amundsen and Bellingshausen Seas. Several differences in model design show a particular influence on the simulations. For example, FESOM's greater topographic smoothing can alter the geometry of some ice shelf cavities enough to affect their melt rates; this improves at higher resolution, since less smoothing is required. In the interior Southern Ocean, the vertical coordinate system affects the degree of water mass erosion due to spurious diapycnal mixing, with MetROMS' terrain-following coordinates leading to more erosion than FESOM's z-15 coordinates. Finally, increased horizontal resolution in FESOM leads to higher basal melt rates for small ice shelves, through a combination of stronger circulation and small-scale intrusions of warm water from offshore.

show abstract

Section: Mixed Layer Depthsupporting

confidence: 66%

Intercomparison of Antarctic ice shelf, ocean, and sea ice interactions simulated by two models

Naughten

Meißner

England

et al. 2017

Preprint

View full text Add to dashboard Cite

show abstract

“…With this volume and cross-sectional area, the 7 year residence time is equivalent to a mean outflow velocity of 1.1 cm s -1, close to the measured average over a 7-month period at that location (PILLSaURV and JACOaS, 1985). However, the assumption that the water beneath the Ross Ice Shelf is well mixed is not supported by temperature and salinity observations there (JACOBS, et al, 1979(JACOBS, et al, , 1985. A stream tube model (MACAYEAL, 1985), based on the assumption that HSSW is transformed in DISW as it flows beneath the ice shelf and mixes little with surrounding water, is probably more realistic than the box model.…”

Section: Deep Ice Shelf Water ( Disw)mentioning

confidence: 99%

Chlorofluorocarbon evidence for rapid ventilation of the Ross Sea

Trumbore

Jacobs

Smethie

1991

Deep Sea Research Part A. Oceanographic Research Papers

View full text Add to dashboard Cite

Abstract---Chlorofluorocarbon (CFC)-I2 and -11 (CF:CI? and CFCI3) measurements were made in seawater on the Ross Sea continental shelf and adjacent slope region in 1984. Concentrations of CFC-12 and CFC-I 1 in Ross Sea continental shelf water averaged nearly half that of saturated surface water. Circumpolar Deep Water within 50 km of the Ross Sea continental shelf also contained measureable CFC-12 and CFC-11, but an order of magnitude less than shelf waters. CFC-12 and CFC-I 1 concentrations in the deep water overlying the continental slope increased with depth, indicating recent ventilation and bottom water formation near the continental shelf.Several water masses on the continental shelf that are commonly distinguished on the basis of temperature and salinity characteristics also varied in CFC content, and thus in their modes and rates of ventilation and renewal. A time-dependent model reproducing the 1984 sub-surface shelf water CFC concentrations demonstrates the relative importance of mixed layer entrainment, gas exchange through leads in the winter sea ice field, and mixing with source waters derived from the Circumpolar Deep W;iter. Model results show that mixed layer entrainment at the beginning of winter is the dominant process ventilating sub-surface shelf water in the eastern Ross Sea. while western shelf waters also reqt,irc signific.'mt gas exchange during winter. Shelf water residence times can only be constrained by the model :rod available data to < lO years, but most probable values arc ~2.5 years in the eastern Ross Sea and ~4 years in the western Ross Sea. CFC concentr.'ttions in water which has circulated beneath and has been moditicd by the Ross Ice Shelf indicate that the transformation time from tligh Salinity Shelf Water to Ice Shelf Water can be as short as 3.5 years. With reasonable oxygen consumption and nutrient regeneration rates, the balance of ventilation anti mixing processes that reproduce observed shelf water CFC-12 concentrations also c:m account fl~r observed oxygen anti nitrate levels, if the western surface waters are undersaturated by ~ I11% at entrainment.

show abstract

“…Water flowing under the Ross Ice Shelf is warmest in the central sector (Jacobs and others, 1979;Pillsbury and Jacobs, 1985) and is also warmer than water flowing beneath the Filchner and Ronne Ice Shelves (Jacobs, 1985). High basal melting rates could contribute to greater local calving by removing the less brittle lower layers of ice (MacAyeal and Thomas, 1986), thus rendering it more susceptible to fracture along existing rifts (Shabtaie and Bentley, 1982).…”

Section: Parts Of Ross Lee Shelf Thickness Maps Compiled By (A) Scottmentioning

confidence: 99%

The Recent Advance of the Ross Ice Shelf Antarctica

1986

Self Cite

View full text Add to dashboard Cite

ABSTRACT. The seaward edge of the Ross Ice Shelf advanced northward at a minimum average velocity of 0.8 km a-1 between 1962 and 1985. That advance approximated velocities that have been obtained from glac~ological data, indicatin~ little r~cent wastage by . iceberg calvmg. West of long. 178 E., the Ice shelf has attamed its most northerly position in the past 145 years, and has not experienced a major calving episode for at least 75 years. Since 1841 the ice-front position has advanced and retreated within a lone from about lat. 77 °10, S. (near long. 171°E.) to lat. 78 40' S. (near long. 164°W.). The central ice front is now farthest south but has the highest advance rate. Calving may occur at more frequent intervals in that sector, which also over lies the warmest ocean currents that flow into the sub-ice-shelf cavity. Available information on ice-shelf advance, thickness, spreading rate, and surface accumulation indicates a basal melting rate around 3 m a-1 near the ice front. These data and independent estimates imply that basal melting is nearly as large a factor as iceberg calving in maintaining the ice-shelf mass balance.

show abstract

Circulation and Melting Beneath the Ross Ice Shelf

Cited by 160 publications

References 17 publications

Intercomparison of Antarctic ice shelf, ocean, and sea ice interactions simulated by two models

Intercomparison of Antarctic ice shelf, ocean, and sea ice interactions simulated by two models

Chlorofluorocarbon evidence for rapid ventilation of the Ross Sea

The Recent Advance of the Ross Ice Shelf Antarctica

Contact Info

Product

Resources

About