Melting of ice shelves and the mass balance of Antarctica

Jacobs, Stan; Helmer, H.H.; Doake, C. S. M.; Jenkins, Adrian; Frolich, R. M.

doi:10.3189/s0022143000002252

Cited by 280 publications

(388 citation statements)

References 97 publications

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“…Runoff from the Antarctic ice sheet is believed to be trivial compared to the fluxes calculated here (Huybrechts and Oerlemans, 1990;Jacobs et al, 1992). …”

Section: Exoreic Runoff Fluxes: Non-glacial and Glacialmentioning

confidence: 69%

Modelled glacial and non-glacial HCO3−, Si and Ge fluxes since the LGM: little potential for impact on atmospheric CO2 concentrations and a potential proxy of continental chemical erosion, the marine Ge/Si ratio

Jones¹,

Munhoven²,

Tranter³

et al. 2002

Global and Planetary Change

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The runoff and riverine fluxes of HCO 3 À , Si and Ge that arise from chemical erosion in non-glaciated terrain, are modelled at six time steps from the Last Glacial Maximum (LGM) to the present day. The fluxes that arise from the Great Ice Sheets are also modelled. Terrestrial HCO 3 À fluxes decrease during deglaciation, largely because of the reduction in the area of the continental shelves as sea level rises. The HCO 3 À fluxes, and the inferred consumption of atmospheric CO 2 are used as inputs to a carbon cycle model that estimates their impact on atmospheric CO 2 concentrations ( atms CO 2 ). A maximum perturbation of atms CO 2 by f 5.5 ppm is calculated. The impact of solutes from glaciated terrain is small in comparison to those from non-glaciated terrain. Little variation in terrestrial Si and Ge fluxes is calculated ( < 10%). However, the global average riverine Ge/Si ratio may be significantly perturbed if the glacial Ge/Si ratio is high. At present, variations in terrestrial chemical erosion appear to have only a reduced impact on atms CO 2 , and only little influence on the global Si and Ge cycle and marine Ge/Si ratios during deglaciation. D

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“…Runoff from the Antarctic ice sheet is believed to be trivial compared to the fluxes calculated here (Huybrechts and Oerlemans, 1990;Jacobs et al, 1992). …”

Section: Exoreic Runoff Fluxes: Non-glacial and Glacialmentioning

confidence: 69%

Modelled glacial and non-glacial HCO3−, Si and Ge fluxes since the LGM: little potential for impact on atmospheric CO2 concentrations and a potential proxy of continental chemical erosion, the marine Ge/Si ratio

Jones¹,

Munhoven²,

Tranter³

et al. 2002

Global and Planetary Change

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“…Precipitation deposited on the Antarctic ice sheet is released as freshwater to the Southern Ocean either locally due to basal melting of floating ice shelves or remotely due to melting of drifting icebergs (Jacobs et al 1992). Extensive caverns underlying the ice shelves which represent ∼11% of the ice sheet area and about 50% of the Antarctic coastline.…”

Section: Introductionmentioning

confidence: 99%

A box model of circulation and melting in ice shelf caverns

Olbers

Hellmer

2009

Ocean Dynamics

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A simple box model of the circulation into and inside the ocean cavern beneath an ice shelf is used to estimate the melt rates of Antarctic glaciers and ice shelves. The model uses simplified cavern geometries and includes a coarse parameterization of the overturning circulation and vertical mixing. The melting/freezing physics at the ice shelf/ocean interface are those usually implemented in high resolution circulation models of ice shelf caverns. The model is driven by the thermohaline inflow conditions and coupling to the heat and freshwater exchanges at the sea surface in front of the cavern. We tune the model for Pine Island Glacier and then apply it to six other major caverns. The dependence of the melting rate on thermohaline conditions at the ice shelf front is investigated for this set of caverns, including sensitivity studies, alternative parameterizations, and warming scenarios. An analytical relation between the melting rate and the inflow temperature is derived for a particular model version, showing a quadratic dependence of basal melting on a small temperature difference between the inflow and the grounding zone which changes to a linear dependence for larger differences.The model predicts melting at all ice shelf bases in agreement with observations, ranging from below a meter per year for Ronne Ice Shelf to about 25 m/y for the Pine Island Glacier. In a warming scenario with a one degree increase of the inflow temperature the latter glacier responds with a 1.4 fold increase of the melting rate. Other caverns respond by more than a ten fold increase, as e.g. Ronne Ice Shelf. The model is suitable for use as simple fast module in coarse large-scale ocean models.

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“…A steady state is assumed in 1992, as for Greenland, as this was when the first evidence of instabilities in the ice sheet was suggested (Doake and Vaughan, 1991;Jacobs et al, 1992), with the freshwater fluxes interpolated back to zero anomalies at this time.…”

Section: Antarctic Ice Sheet Component Of Freshwatermentioning

confidence: 99%

The land-ice contribution to 21st-century dynamic sea level rise

et al. 2014

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Abstract. Climate change has the potential to influence global mean sea level through a number of processes including (but not limited to) thermal expansion of the oceans and enhanced land ice melt. In addition to their contribution to global mean sea level change, these two processes (among others) lead to local departures from the global mean sea level change, through a number of mechanisms including the effect on spatial variations in the change of water density and transport, usually termed dynamic sea level changes.In this study, we focus on the component of dynamic sea level change that might be given by additional freshwater inflow to the ocean under scenarios of 21st-century land-based ice melt. We present regional patterns of dynamic sea level change given by a global-coupled atmosphere-ocean climate model forced by spatially and temporally varying projected ice-melt fluxes from three sources: the Antarctic ice sheet, the Greenland Ice Sheet and small glaciers and ice caps. The largest ice melt flux we consider is equivalent to almost 0.7 m of global mean sea level rise over the 21st century. The temporal evolution of the dynamic sea level changes, in the presence of considerable variations in the ice melt flux, is also analysed.We find that the dynamic sea level change associated with the ice melt is small, with the largest changes occurring in the North Atlantic amounting to 3 cm above the global mean rise. Furthermore, the dynamic sea level change associated with the ice melt is similar regardless of whether the simulated ice fluxes are applied to a simulation with fixed CO 2 or under a business-as-usual greenhouse gas warming scenario of increasing CO 2 .

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Melting of ice shelves and the mass balance of Antarctica

Cited by 280 publications

References 97 publications

Modelled glacial and non-glacial HCO3−, Si and Ge fluxes since the LGM: little potential for impact on atmospheric CO2 concentrations and a potential proxy of continental chemical erosion, the marine Ge/Si ratio

Modelled glacial and non-glacial HCO3−, Si and Ge fluxes since the LGM: little potential for impact on atmospheric CO2 concentrations and a potential proxy of continental chemical erosion, the marine Ge/Si ratio

A box model of circulation and melting in ice shelf caverns

The land-ice contribution to 21st-century dynamic sea level rise

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