Thermal convection and the origin of ice streams

Hughes, Terence J.

doi:10.3189/002214309788816722

Cited by 9 publications

(25 citation statements)

References 53 publications

(88 reference statements)

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“…Also open to debate are the reasons that explain the observed accelerated glacier flow along polar coasts and the role of sea ice. In this respect it has been proposed that thermal convection may play a role in the origin of ice streams (Hughes, 2009). Also related to glaciers are open questions regarding the sintering process of glacial snow.…”

Section: Perspectivesmentioning

confidence: 99%

Ice structures, patterns, and processes: A view across the icefields

et al. 2012

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We look ahead from the frontiers of research on ice dynamics in its broadest sense; on the structures of ice, the patterns or morphologies it may assume, and the physical and chemical processes in which it is involved. We highlight open questions in the various fields of ice research in nature; ranging from terrestrial and oceanic ice on Earth, to ice in the atmosphere, to ice on other solar system bodies and in interstellar space.

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Section: Perspectivesmentioning

confidence: 99%

Ice structures, patterns, and processes: A view across the icefields

et al. 2012

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“…The suggestion that ice-stream tributaries are the surface expression of underlying convection rolls [5,21] is supported by temperature profiles obtained from hotpoint drilling to the bed, showing warmer ice in Whillans Ice Stream and colder ice in Ice Ridge B1-B2, informally called the "Unicorn" [24]. In between is a lateral shear zone, which would add warmer ascending convecting ice to advective ice flow from the ice ridge to the ice stream.…”

Section: Theorymentioning

confidence: 98%

“…In 2009, a new perspective on how convective and advective flow could be linked [21] followed the 1976 suggestion that tributaries supplying major Antarctic ice streams are the surface expression of underlying convection rolls [5]. Figure 1 illustrates this new perspective.…”

Section: New Data New Ideasmentioning

confidence: 99%

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Thermal convection in ice sheets: New data, new tests

Hughes

2012

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Thermal convection in the Antarctic Ice Sheet was proposed in 1970. Demonstrating its existence proved to be elusive. In 2009, tributaries to ice streams were postulated as the surface expression of underlying thermal convection rolls aligned in directions of advective ice flow. Two definitive tests of this hypothesis are now possible, using highly accurate ice elevations and velocities provided by the European, Japanese, and Canadian Space Agencies that allow icestream tributaries and their velocities to be mapped. These tests are 1) measuring lowering of tributary surfaces to see if lowering is due only to advective ice thinning, or also requires lowering en masse in the broad descending part of convective flow, and 2) measuring transverse surface ice velocities to see if ice entering tributaries from the sides increases while crossing lateral shear zones, as would be required if this flow is augmented by convective flow ascending in the narrow side shear zones and diverted into tributaries by advective ice flow. If (1) and (2) are applied to tributaries converging on Byrd Glacier, the same measurements can be conducted when tributaries pack together to become “flow stripes” down Byrd Glacier and onto the Ross Ice Shelf to see if (2) is reduced when lateral advection stops. This could determine if thermal convection remains active or shuts down as ice thins. Thermal convection in the Antarctic Ice Sheet would raise three questions. Can it cause the ice sheet to self-destruct as convective flow turns on and off? Does it render invalid climate records extracted at depth from ice cores? Can the ice sheet be studied as a miniature mantle analogous in some respects to Earth’s mantle

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“…On the face of it, they have nothing to do with each other. This is the instinctive reaction of the dynamicist, and Hughes's proposal, preceded by his earlier enquiries (Hughes, 1976(Hughes, , 2009, has not attracted much attention. The texts of Cuffey and Paterson (2010) and Hooke (2005) provide no index reference to convection.…”

mentioning

confidence: 99%