Climatic conditions, mass balance and dynamics of Larsen B ice shelf, Antarctic Peninsula, prior to collapse

Skvarca, Pedro; Angelis, Hernán De; Zakrajsek, Andrés F

doi:10.3189/172756404781814573

Cited by 26 publications

(28 citation statements)

References 23 publications

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“…It also appears to have begun retreating earlier, without any significant re-advance. Here the ice shelf is significantly thicker (a maximum of 600 m) and wider (over 70 km) than at the northern front (Smith et al, 2007). There is little sea-ice build-up within the Ronne Entrance which also differs from the northern end of George VI Sound.…”

Section: George VI Ice Shelfmentioning

confidence: 86%

“…Oceanographic observations in this region are limited, however, and another study has shown that regional ocean warming may not have had a major impact on basal melt rates (Nicholls et al, 2004). Other changes in the ice-shelf dynamics prior to their collapse have also been detected, such as an acceleration in iceshelf flow of up to 50%, revealed through observations using satellite radar interferometry for the Larsen B Ice Shelf Vieli et al, 2006;Skvarca et al, 2003). It has been speculated that the ice-shelf acceleration is explained by the retreat of the ice front but also by further rheological weakening of the shear margins, and not by the observed thinning or the acceleration of tributary glaciers (which appear to be an effect, not a cause of ice-shelf acceleration) (Vieli et al, 2007;Khazendar et al, 2007).…”

Section: Larsen a And Larsen B Ice Shelvesmentioning

confidence: 99%

“…The overall pattern of retreat of both ice fronts coincides with the well-documented atmospheric warming across the AP, but since the southern ice front retreat preceded retreat at the northern ice front, it cannot be interpreted simply as a result of the southern migration of a key mean annual isotherm (Smith et al, 2007). It is likely that the southern ice front is also responding to other forcing mechanisms and feedbacks (e.g.…”

Section: George VI Ice Shelfmentioning

confidence: 99%

“…4.4) George VI Ice Shelf is the largest ice shelf on the west coast of the AP, covering a total area of ∼ 24000 km 2 . It is unusual in two respects, as discussed in Smith et al, 2007. Firstly, it has two ice fronts that are almost 500 km apart and experience quite different climatic conditions.…”

Section: During the British Graham Land Expeditionmentioning

confidence: 99%

“…The thinning of floating glaciers in the West Antarctic Ice Sheet (WAIS) region has been attributed to heat contained within the CDW flowing towards the continent via a submarine glacial trough and driving basal melting (Walker et al, 2007). In order to assess whether George VI Ice Shelf has entered a phase of rapid retreat and whether this is largely driven by atmospheric warming, basal melting, or both, requires further work (Smith et al, 2007). (Fig.…”

Section: George VI Ice Shelfmentioning

confidence: 99%

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Overview of areal changes of the ice shelves on the Antarctic Peninsula over the past 50 years

2010

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Abstract. In recent decades, seven out of twelve ice shelves around the Antarctic Peninsula (AP) have either retreated significantly or have been almost entirely lost. At least some of these retreats have been shown to be unusual within the context of the Holocene and have been widely attributed to recent atmospheric and oceanic changes. To date, measurements of the area of ice shelves on the AP have either been approximated, or calculated for individual shelves over dissimilar time intervals. Here we present a new dataset containing up-to-date and consistent area calculations for each of the twelve ice shelves on the AP over the past five decades. The results reveal an overall reduction in total ice-shelf area by over 28 000 km 2 since the beginning of the period. Individual ice shelves show different rates of retreat, ranging from slow but progressive retreat to abrupt collapse. We discuss the pertinent features of each ice shelf and also broad spatial and temporal patterns in the timing and rate of retreat. We believe that an understanding of this diversity and what it implies about the underlying dynamics and control will provide the best foundation for developing a reliable predictive skill for ice-shelf change.

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Section: George VI Ice Shelfmentioning

confidence: 86%

Section: Larsen a And Larsen B Ice Shelvesmentioning

confidence: 99%

Section: George VI Ice Shelfmentioning

confidence: 99%

Section: During the British Graham Land Expeditionmentioning

confidence: 99%

Section: George VI Ice Shelfmentioning

confidence: 99%

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Overview of areal changes of the ice shelves on the Antarctic Peninsula over the past 50 years

2010

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Foehn winds link climate‐driven warming to ice shelf evolution in Antarctica

Cape

Vernet

Skvarca³

et al. 2015

JGR Atmospheres

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143

172

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Rapid warming of the Antarctic Peninsula over the past several decades has led to extensive surface melting on its eastern side, and the disintegration of the Prince Gustav, Larsen A, and Larsen B ice shelves. The warming trend has been attributed to strengthening of circumpolar westerlies resulting from a positive trend in the Southern Annular Mode (SAM), which is thought to promote more frequent warm, dry, downsloping foehn winds along the lee, or eastern side, of the peninsula. We examined variability in foehn frequency and its relationship to temperature and patterns of synoptic-scale circulation using a multidecadal meteorological record from the Argentine station Matienzo, located between the Larsen A and B embayments. This record was further augmented with a network of six weather stations installed under the U.S. NSF LARsen Ice Shelf System, Antarctica, project. Significant warming was observed in all seasons at Matienzo, with the largest seasonal increase occurring in austral winter (+3.71 ∘ C between 1962-1972 and 1999-2010). Frequency and duration of foehn events were found to strongly influence regional temperature variability over hourly to seasonal time scales. Surface temperature and foehn winds were also sensitive to climate variability, with both variables exhibiting strong, positive correlations with the SAM index. Concomitant positive trends in foehn frequency, temperature, and SAM are present during austral summer, with sustained foehn events consistently associated with surface melting across the ice sheet and ice shelves. These observations support the notion that increased foehn frequency played a critical role in precipitating the collapse of the Larsen B ice shelf.

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Revealing the early ice flow patterns with historical Declassified Intelligence Satellite Photographs back to 1960s

Wang

Liu

et al. 2016

Geophysical Research Letters

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The reconnaissance ARGON satellites collected the earliest images of Antarctica from space dating back to the 1960s, providing valuable historical baseline information for studying polar ice sheets. Those photographs are underutilized for ice motion mapping, due to lack of sufficient ground controls for image orthorectification. In this study, we orthorectified the ARGON photographs by fully exploiting the metric qualities of WorldView satellite images: very high spatial resolution and precise geolocation. Through a case study over Larsen Ice Shelf, we demonstrated that the camera model with bundle block adjustment can achieve geolocation accuracy of better than the nominal resolution (140 m) for orthorectifying ARGON images, with WorldView imagery as ground control source. This allowed us to extend the ice velocity records of Larsen Ice Shelf back into 1960s~1970s for the first time. The retrospective analysis revealed that acceleration of the collapsed Larsen B occurred much earlier than previously thought.

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Climatic conditions, mass balance and dynamics of Larsen B ice shelf, Antarctic Peninsula, prior to collapse

Cited by 26 publications

References 23 publications

Overview of areal changes of the ice shelves on the Antarctic Peninsula over the past 50 years

Overview of areal changes of the ice shelves on the Antarctic Peninsula over the past 50 years

Foehn winds link climate‐driven warming to ice shelf evolution in Antarctica

Revealing the early ice flow patterns with historical Declassified Intelligence Satellite Photographs back to 1960s

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