Hagen Bræ: A Surging Glacier in North Greenland—35 Years of Observations

Solgaard, Anne; Simonsen, Sebastian B.; Grinsted, Aslak; Mottram, Ruth; Karlsson, Nanna B.; Hansen, Kasper Hjorth; Kusk, Anders; Sørensen, Louise Sandberg

doi:10.1029/2019gl085802

Cited by 16 publications

(16 citation statements)

References 49 publications

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“…The offset-tracking procedure employed is similar to the one described in Strozzi et al (2002) and estimates local shifts between two SLCs in radar geometry using normalized cross-correlation of intensity image patches. It is illustrated in Fig.…”

Section: Offset Trackingmentioning

confidence: 99%

Greenland ice velocity maps from the PROMICE project

Solgaard

Kusk

Boncori

et al. 2021

Earth Syst. Sci. Data

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Abstract. We present the Programme for Monitoring of the Greenland Ice Sheet (PROMICE) Ice Velocity product (https://doi.org/10.22008/promice/data/sentinel1icevelocity/greenlandicesheet, Solgaard and Kusk, 2021), which is a time series of Greenland Ice Sheet ice velocity mosaics spanning September 2016 through to the present. The product is based on Sentinel-1 synthetic aperture radar data and has a 500 m grid spacing. A new mosaic is available every 12 d and spans two consecutive Sentinel-1 cycles (24 d). The product is made available within ∼ 10 d of the last acquisition and includes all possible 6 and 12 d pairs within the two Sentinel-1A cycles. We describe our operational processing chain from data selection, mosaicking, and error estimation to final outlier removal. The product is validated against in situ GPS measurements. We find that the standard deviation of the difference between satellite- and GPS-derived velocities (and bias) is 20 m yr−1 (−3 m yr−1) and 27 m yr−1 (−2 m yr−1) for the components in an eastern and northern direction, respectively. Over stable ground the values are 8 m yr−1 (0.1 m yr−1) and 12 m yr−1 (−0.6 m yr−1) in an eastern and northern direction, respectively. This is within the expected values; however, we expect that the GPS measurements carry a considerable part of this uncertainty. We investigate variations in coverage from both a temporal and spatial perspective. The best spatial coverage is achieved in winter due to the comprehensive data coverage by Sentinel-1 and high coherence, while summer mosaics have the lowest coverage due to widespread melt. The southeast Greenland Ice Sheet margin, along with other areas of high accumulation and melt, often has gaps in the ice velocity mosaics. The spatial comprehensiveness and temporal consistency make the product ideal both for monitoring and for studying ice-sheet-wide and glacier-specific ice discharge and dynamics of glaciers on seasonal scales.

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Section: Offset Trackingmentioning

confidence: 99%

Greenland ice velocity maps from the PROMICE project

Solgaard

Kusk

Boncori

et al. 2021

Earth Syst. Sci. Data

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“…But the summer survival rate of sea ice on the Siberian Shelf is decreasing by 15 % per decade (Krumpen et al, 2019). That is, in the 1990s, 50 % of first-year ice entered the transpolar drift; now, it is less than 20 %, as the rest melts before reaching the transpolar drift (Spall, 2019;Krumpen et al, 2019).…”

Section: Sea Icementioning

confidence: 99%

“…In addition, Morison et al (2021) recently provide a longer-term perspective on freshwater distribution and stress the importance of the cyclonic mode of ocean circulation on the Atlantic-Eurasian side of the Arctic Ocean, in addition to the conventionally emphasized Beaufort Gyre. The cyclonic mode is characterized as the first empirical orthogonal function (EOF) of ocean surface height variability (dynamic heights for 1959and satellite DOT for 2004-2019. In the cyclonic phase, surface depression, reduced freshwater content, and cyclonic circulation occurred on the Atlantic-Eurasian side of the Arctic Ocean.…”

Section: Wind-driven Circulationmentioning

confidence: 99%

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Freshwater in the Arctic Ocean 2010–2019

Solomon

Heuzé²,

Rabe

et al. 2021

Ocean Sci.

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Abstract. The Arctic climate system is rapidly transitioning into a new regime with a reduction in the extent of sea ice, enhanced mixing in the ocean and atmosphere, and thus enhanced coupling within the ocean–ice–atmosphere system; these physical changes are leading to ecosystem changes in the Arctic Ocean. In this review paper, we assess one of the critically important aspects of this new regime, the variability of Arctic freshwater, which plays a fundamental role in the Arctic climate system by impacting ocean stratification and sea ice formation or melt. Liquid and solid freshwater exports also affect the global climate system, notably by impacting the global ocean overturning circulation. We assess how freshwater budgets have changed relative to the 2000–2010 period. We include discussions of processes such as poleward atmospheric moisture transport, runoff from the Greenland Ice Sheet and Arctic glaciers, the role of snow on sea ice, and vertical redistribution. Notably, sea ice cover has become more seasonal and more mobile; the mass loss of the Greenland Ice Sheet increased in the 2010s (particularly in the western, northern, and southern regions) and imported warm, salty Atlantic waters have shoaled. During 2000–2010, the Arctic Oscillation and moisture transport into the Arctic are in-phase and have a positive trend. This cyclonic atmospheric circulation pattern forces reduced freshwater content on the Atlantic–Eurasian side of the Arctic Ocean and freshwater gains in the Beaufort Gyre. We show that the trend in Arctic freshwater content in the 2010s has stabilized relative to the 2000s, potentially due to an increased compensation between a freshening of the Beaufort Gyre and a reduction in freshwater in the rest of the Arctic Ocean. However, large inter-model spread across the ocean reanalyses and uncertainty in the observations used in this study prevent a definitive conclusion about the degree of this compensation.

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“…However, the Storstrømmen Glacier and Bistrup Brae in East Greenland are probably the largest surge-type glaciers in the world showing characteristics of Svalbard type (Mouginot et al, 2018). The 35year investigation of ice velocities in combination with observations of surface elevation and glacier area change of Hagen Brae in the north of Greenland shows that Hagen Brae Glacier is a glacier with two characteristics of Alaska and Svalbard (Solgaard et al, 2020). In addition, some surging glaciers are known to exist on Disko Island (Qeqertarsuaq) and the Nuussuaq peninsula in West Greenland (Yde and Knudsen, 2007).…”

Section: The Distribution Of Surge-type Glaciersmentioning

confidence: 99%

A Review of Surge-Type Glaciers

Sun

Qiao

2021

Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci.

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Abstract. The study of glacier surges is meaningful for the understanding of glacier dynamics and the mechanisms of surge-type glaciers. Here, we briefly introduce the distribution of surge-type glaciers and the reason of their tendency to cluster within particular regions. Then we make a review of optical and SAR remote sensing methods for the spaceborne measurement of the surface velocity about surge-type glaciers and show the details of characteristics of Surging Glaciers including the acceleration and deceleration of the velocity of the glacier surface, the terminus may move forward a few kilometers in just a few months, then we give a specific example of surge-type glacier, Sortebræ. Finally, we summarize the existing mechanism of the glaciers surging.

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Hagen Bræ: A Surging Glacier in North Greenland—35 Years of Observations

Cited by 16 publications

References 49 publications

Greenland ice velocity maps from the PROMICE project

Greenland ice velocity maps from the PROMICE project

Freshwater in the Arctic Ocean 2010–2019

A Review of Surge-Type Glaciers

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