Glaciology of the McMurdo Ice Shelf in the area of air operations

Klokov, Valeri; Diemand, Deborah

doi:10.1029/ar067p0175

Cited by 10 publications

(9 citation statements)

References 4 publications

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“…Despite the migrated seal population, no physical evidence has been found within the ice shelf to confirm this retreat or fracturing. However, surface melting on MIS and broader Antarctic ice shelf instability has been of scientific concern since the 1960s (Stuart and Bull, 1963; Paige, 1968; Kovacs and Gow, 1975; Klokov and Diemand, 1995). A heightened level of concern for the long-term future of the MIS, both from a logistical and scientific standpoint, stems from recent findings of instability within the West Antarctic Ice Sheet and the surrounding ice shelves (e.g.…”

Section: Introductionmentioning

confidence: 99%

Brine, englacial structure and basal properties near the terminus of McMurdo Ice Shelf, Antarctica

et al. 2017

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ABSTRACT. We collected ∼1300 km of ground-penetrating radar profiles over McMurdo Ice Shelf, Antarctica, using frequencies between 40 and 400 MHz to determine extent, continuity and depth to the brine. We also used profiles to determine meteoric ice thickness and locate englacial features, which may suggest ice shelf instability. The brine extends 9-13 km inland from the ice shelf terminus and covers the entire region between Ross, White and Black Islands. Jump unconformities and basal fractures exist in the brine and ice shelf, respectively, suggesting prior fracturing and re-suturing. One 100 MHz profile, the most distal from the ice shelf edge while still being situated over the brine, simultaneously imaged the brine and bottom of meteoric ice. This suggests a negative brine salinity gradient moving away from the terminus. The meteoric ice bottom was also imaged in a few select locations through blue ice in the ablation zone near Black Island. We suggest that brine, sediment-rich ice and poor antenna coupling on rough ice attenuates the signal in this area. When combined with other recent mass-balance and structural glaciology studies of MIS, our results could contribute to one of the most high-resolution physical models of an ice shelf in Antarctica.

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Section: Introductionmentioning

confidence: 99%

Brine, englacial structure and basal properties near the terminus of McMurdo Ice Shelf, Antarctica

et al. 2017

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“…and the required top-layer strength. Abele (1990), Table 7 c Palt (2017) d Mellor (1993) e USAF (2015a), Table B-1 f Klokov and Diemand (1995) Figure 24. Comparison of snow runway pavement strength profiles (1 psi = 0.006895 MPa).…”

Section: Snow Runway Strengthmentioning

confidence: 99%

A snow runway for supporting wheeled aircraft : Phoenix Airfield, McMurdo, Antarctica

Haehnel¹,

Blaisdell²,

Melendy³

et al. 2019

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“…A giant cross-section of the area in the winter, when everything is frozen, would most likely display elongated pods of large-crystal “blue” ice scattered along near the surface and embedded within fine-grained, milky glacial ice. Klokov and Diemand (1994) have dissected a frozen melt pool and described its features, including a gap at the meltwater glacial ice boundary (Fig. 12).…”

Section: Evidence Supporting Meltwater Occurrencementioning

confidence: 99%

Localized surface-ice weakness on a glacial ice runway

Lang

Blaisdell

1996

J. Glaciol.

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ABSTRACT. Following con stru ction of a g lacial ice runwa y o n th e R oss Ice Shelf, Antarcti ca, and prior to fli g ht operations, th e runway was proof-rolled. Th e proof exercise was d es igned to simulate typica l heavy aircraft. Initia l tes ting produ ced num erous brittle surface failures in the runway ice. Thin sectio ns of ice co res taken from th e fail ed a reas showed large crystals (c ax is ve rti ca l) of cl ear , blu e ice with lon g, verti ca l bubbl es, indicative of ic e form ed direc tl y from meltwater. Uniaxialunconfined compression tes ts on core sample. were used to compare runway ice strength with published data for polyc rys talline la bora tory ice. Since the freq u e n t failure of surface ice had not bee n expec ted , it was criti cal to und e rsta nd the form a tion and mechani ca l properti es of th e weak ice to pre\'e nt its occ urrence in the future a nd to strengthen th e existing problem a reas. We discuss th e likely sce narios for devel o pment of weak ice o n the airstrip and the physical properti es of this typ e of ice. Also, the procedure used LO repa ir success full y th e runway surface is desc ribed , whi ch culminated in tes t fli ghts, followed by full fli ght opera tions. INTRODUCTIONa n a lternating ta ll-a nd short-tooth pattern to assist In cleaning the surface of all debris. Th e includ ed a ng le of the cutting tee th w as 42° and sid e-relief a ngles were 41°. A laser-gu id ance sys tem assisted in producing a n acc ura te g rade even when th e g rader operator had great dif1icu lty seeing well enou g h to drive in a stra ig ht lin e. Snow and ice debris were r emoved from th e runway surface with a Rolb a rota ry sn ow -blo\\·er. (For a more co mpl e te

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Glaciology of the McMurdo Ice Shelf in the area of air operations

Cited by 10 publications

References 4 publications

Brine, englacial structure and basal properties near the terminus of McMurdo Ice Shelf, Antarctica

Brine, englacial structure and basal properties near the terminus of McMurdo Ice Shelf, Antarctica

A snow runway for supporting wheeled aircraft : Phoenix Airfield, McMurdo, Antarctica

Localized surface-ice weakness on a glacial ice runway

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