Wintertime heat flux to the underside of East Antarctic pack ice

Lytle, VI; Massom, Robert A.; Bindoff, Nathaniel L.; Worby, A. P.; Allison, Ian

doi:10.1029/2000jc900099

Cited by 24 publications

(26 citation statements)

References 36 publications

(21 reference statements)

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“…A similar type of flooding event was observed during the winter HIHO HIHO experiment (Lytle and others, 2000) in the East Antarctic sea-ice pack at about 65° S, 145° E. The data, which are discussed in Golden and others (1998c), demonstrate clearly that an air-temperature increase alone can cause the permeability phase transition.…”

Section: Percolation and The Fluid Permeability Of Sea Icesupporting

confidence: 62%

Brine percolation and the transport properties of sea ice

Golden

2001

Ann. Glaciol.

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Sea ice is distinguished from many other porous composites, such as sandstones or bone, in that its microstructure and bulk material properties can vary dramatically over a small temperature range. For brine-volume fractions below a critical value of about 5%, which corresponds to a critical temperature of about −5°C for salinity of 5 ppt, columnar sea ice is effectively impermeable to fluid transport. For higher brine volumes, the brine phase becomes connected and the sea ice is permeable, allowing transport of brine, sea water, nutrients, biomass and heat through the ice. Over the past several years it has been found that brine transport is fundamental to such processes as sea-ice production through freezing of flooded ice surfaces, the enhancement of thermal and salt fluxes through sea ice, nutrient replenishment for sea-ice algal communities, and to sea-ice remote sensing. Motivated by these observations, recently we have shown how percolation theory can be used to understand the critical behavior of fluid transport in sea ice. We applied a percolation model developed for compressed powders of large polymer particles with much smaller metal particles, which explains the observed behavior of the fluid permeability in the critical temperature regime, as well as Antarctic data on surface flooding and algal growth rates. Moreover, the connectedness properties of the brine phase play a significant role in the microwave signature of sea ice through its effective complex permittivity and surface flooding. Here we review our recent results on brine percolation and its role in understanding the fluid and electromagnetic transport properties of sea ice. We also briefly report on measurements of percolation we made on first-year sea ice during the winter 1999 Mertz Glacier Polynya Experiment.

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Section: Percolation and The Fluid Permeability Of Sea Icesupporting

confidence: 62%

Brine percolation and the transport properties of sea ice

Golden

2001

Ann. Glaciol.

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“…On the other hand, ice temperature profiles, combined with measurements of ice bottom ablation or accretion also provide an estimate of the time averaged oceanic heat flux. This so‐called residual method [ McPhee and Untersteiner , 1982], was adopted to calculate the oceanic heat fluxes under pack ice in Alaskan Beaufort Sea [ Perovich and Elder , 2002], under pack ice in east Antarctica [ Lytle et al , 2000], and under landfast ice in McMurdo Sound [ Purdie et al , 2006]. Here, we use this method to estimate the 2006 oceanic heat flux under landfast ice near Zhongshan.…”

Section: Resultsmentioning

confidence: 99%

Annual cycle of landfast sea ice in Prydz Bay, east Antarctica

Lei¹,

Li²,

Cheng³

et al. 2010

J. Geophys. Res.

139

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Under the Chinese National Antarctic Research Expedition program in 2006, the annual thermal mass balance of landfast ice in the vicinity of Zhongshan Station, Prydz Bay, east Antarctica, was investigated. Sea ice formed from mid‐February onward, and maximum ice thickness occurred in late November. Snow cover remained thin, and blowing snow caused frequent redistribution of the snow. The vertical ice salinity showed a “question‐mark‐shaped” profile for most of the ice growth season, which only turned into an “I‐shaped” profile after the onset of ice melt. The oceanic heat flux as estimated from a flux balance at ice‐ocean interface using internal ice temperatures decreased from 11.8 (±3.5) W m−2 in April to an annual minimum of 1.9 (±2.4) W m−2 in September. It remained low through late November, in mid‐December it increased sharply to about 20.0 W m−2. Simulations applying the modified versions of Stefan's law, taking account the oceanic heat flux and ice‐atmosphere coupling, compare well with observed ice growth. There was no obvious seasonal cycle for the thermal conductivity of snow cover, which was also derived from internal ice temperatures. Its annual mean was 0.20 (±0.04) W m‐1 °C−1.

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“…Although the ocean heat fluxes are small (13.8 W m −2 for HMCDW to HSSW and 7.7 W m −2 for HMCDW to WW) compared to the latent-heat fluxes, they are in good qualitative agreement with other direct and indirect measures of ocean heat fluxes. Lytle and others (2000) estimate ocean heat fluxes of 13.0−14.5 W m −2 over the Antarctic Divergence at 140° E. In the Weddell Gyre, Fahrbach and others (1994) estimate 19 W m −2 , while from observations of fast ice, Heil and others (1996) found a heat-flux range of 0−18 W m −2 . Similarly, the estimates of ocean heat fluxes inferred from models are 5−30 Wm" 2 depending on the season (Wu and others, 1997).…”

Section: Discussionmentioning

confidence: 99%

Sea-ice growth and water-mass modification in the Mertz Glacier polynya, East Antarctica, during winter

2001

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ABSTRACT. In July^September 1999, an extensive oceanographic survey (87 conductivity-, temperature-and depth-measuring stations) was conducted in the Mertz Glacier polynya over the Ade¨lie Depression off the Antarctic coast between 145³ and 150³ E.We identify and describe four key water masses in this polynya: highly modified circumpolar deep water (HMCDW), winter water (WW), ice-shelf water (ISW) and high-salinity shelf water (HSSW). Combining surface velocity data (from an acoustic Doppler current-profiler) with three hydrographic sections, we found the HMCDW to be flowing westward along the shelf break (0.7 Sv), theWWand HSSW flowing eastwards underneath Mertz Glacier (2.0 Sv) and that there was a westward return flow of ISW against the continent (1.2 Sv). Using a simple box model for the exchanges of heat and fresh water between the principal water masses, we find that the polynya was primarily a latent-heat polynya with 95% of the total heat flux caused by sea-ice formation. This heat flux results from a fresh-water-equivalent sea-ice growth rate of 4.9^7.7 cm d^1 and a mass exchange between HMCDW and WW of 1.45 Sv The inferred ocean heat flux is 8^14 W m^2 and compares well with other indirect estimates.

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Wintertime heat flux to the underside of East Antarctic pack ice

Cited by 24 publications

References 36 publications

Brine percolation and the transport properties of sea ice

Brine percolation and the transport properties of sea ice

Annual cycle of landfast sea ice in Prydz Bay, east Antarctica

Sea-ice growth and water-mass modification in the Mertz Glacier polynya, East Antarctica, during winter

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