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Asurge of Skobreen/Paulabreen, Svalbard, observed by time-lapse photographs and remote sensing data

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We present observations of a surge of the glaciers Skobreen-Paulabreen, Svalbard, during 2003-05, including a time-lapse movie of the frontal advance during 2005, Advanced Spaceborne Thermal Emission (ASTER) imagery and oblique aerial photographs. The surge initiated in Skobreen, and then propagated downglacier into the lower parts of Paulabreen. ASTER satellite images from different stages of the surge are used to evaluate the surge progression. Features on the glacier surface advanced 2800 m over 2.4 yr, averaging 3.2 m/day, while the front advanced less (ca. 1300 m) due to contemporaneous calving. The surge resulted in a lateral displacement of the medial moraines of Paulabreen of ca. 600 m at the glacier front. The time-lapse movie captured the advance of the frontal part of the glacier, and dramatically illustrates glacier dynamic processes in an accessible way. The movie documents a range of processes such as a plug-like flow of the glacier, proglacial thrusting, incorporation of old, dead ice at the margin, and calving into the fjord. The movie provides a useful resource for researchers, educators seeking to teach and inspire students, and those wishing to communicate the fascination of glacier science to a wider public.
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RESEARCH/REVIEW ARTICLE
A surge of the glaciers Skobreen
Paulabreen, Svalbard, observed
by time-lapse photographs and remote sensing data
Lene Kristensen
1
& Douglas I. Benn
1,2
1
Department of Arctic Geology, The University Centre in Svalbard, NO-9171 Longyearbyen, Norway
2
School of Geography and Geosciences, Irvine Building, University of St Andrews, North Street, KY16 9AL Fife, UK
Keywords
Glacier surge; time-lapse movie; Skobreen;
Paulabreen; Svalbard.
Correspondence
Douglas I. Benn, Department of Arctic
Geology, The University Centre in Svalbard,
PO Box 156, NO-9171 Longyearbyen,
Norway.
E-mail: doug.benn@unis.no
Abstract
We present observations of a surge of the glaciers SkobreenPaulabreen,
Svalbard, during 200305, including a time-lapse movie of the frontal advance
during 2005, Advanced Spaceborne Thermal Emission (ASTER) imagery
and oblique aerial photographs. The surge initiated in Skobreen, and then
propagated downglacier into the lower parts of Paulabreen. ASTER satellite
images from different stages of the surge are used to evaluate the surge
progression. Features on the glacier surface advanced 2800 m over 2.4 yr,
averaging 3.2 m/day, while the front advanced less (ca. 1300 m) due to
contemporaneous calving. The surge resulted in a lateral displacement of the
medial moraines of Paulabreen of ca. 600 m at the glacier front. The time-lapse
movie captured the advance of the frontal part of the glacier, and dramatically
illustrates glacier dynamic processes in an accessible way. The movie docu-
ments a range of processes such as a plug-like flow of the glacier, proglacial
thrusting, incorporation of old, dead ice at the margin, and calving into the
fjord. The movie provides a useful resource for researchers, educators seek-
ing to teach and inspire students, and those wishing to communicate the
fascination of glacier science to a wider public.
Surges are among the most dramatic of all glacial
phenomena. When a glacier surges, ice velocities can
increase by one or two orders of magnitude, drawing
down ice from reservoir areas towards the front, in some
cases producing ice-front advances of several kilometres.
These radical transformations reflect switches in the
thermal and/or hydrological conditions at the glacier
bed, resulting from some combination of internal dy-
namic processes and external environmental conditions
(e.g., Kamb et al. 1985; Eisen et al. 2001; Fowler et al.
2001; Hewitt 2007). The classic definition of surging
glaciers emphasizes quasi-periodic velocity fluctuations,
in which glaciers cycle between periods of rapid motion
lasting a few months to several years*the surge or
active stage*and periods of slow flow lasting several
years to decades*quiescent periods (Meier & Post 1969;
Dowdeswell et al. 1995). Other glaciers have been ob-
served to surge only once, and it may be unclear whether
the surge was an isolated occurrence or if the surge
return period was longer than the period of observation.
Few surging glaciers have been studied in detail,
although it is clear that they can exhibit a very wide
range of behaviour. Surges can be ‘‘fast’’ (with velocities
of several kilometres per year) or ‘‘slow’’ (with velocities
of a few tens of metres per year); they can affect both
temperate and polythermal glaciers, and land-based and
calving glaciers (Harrison & Post 2003; Murray et al.
2003; Nolan 2003; Frappe & Clarke 2007).
Surging glaciers are of great interest scientifically,
because they can shed light on dynamic instabilities
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Citation: Polar Research 2012, 31, 11106, http://dx.doi.org/10.3402/polar.v31i0.11106
and threshold behaviour in glacier systems. Study of the
geomorphological and sedimentological products of sur-
ging glaciers can allow glacial geologists to better inter-
pret evidence for past glacier activity and its climatic
implications (Evans & Rea 2003; Ottesen et al. 2008).
Additionally, surges provide educators with spectacular
examples of glacier behaviour, which can capture the
interest and imagination of students and lay people alike.
In 2005, Paulabreen, a tidewater-terminating glacier
in Svalbard, underwent a rapid advance which was
the culmination of a surge that started several years
earlier on its tributary glacier, Skobreen (Sund 2006).
We were able to record this event using time-lapse
photography, using an automatic camera installed near
the glacier front. To our knowledge, this movie was the
first to capture a surge of a polythermal glacier, providing
striking evidence for glaciological and geomorphological
processes at the surge front. In this contribution, we
make the movie available for download and provide a
commentary describing the main features that can be
seen as the surge progresses (see Supplementary File).
In addition, we include a selection of satellite images
and aerial photographs that place the movie in a wider
context, and provide a record of glacier evolution during
the surge. Taken together, the movie and images provide
a resource for the research community and educators,
which illustrates the progress of a High-Arctic surge and
its impacts on the proglacial environment.
Study area and glaciological background
Svalbard is one of several regions in the world with a
high concentration of surge-type glaciers. Estimates of
the percentage of Svalbard glaciers that are of this type
range from 13% to 90%, depending on the criteria used
for inclusion (Hagen et al. 1993; Hamilton & Dowdeswell
1996; Jiskoot et al. 1998). The surge and the quiescent
periods are somewhat longer lasting for Svalbard glaciers
(40500 yr for the quiescent period) than for surge-type
glaciers in other regions of the world (Dowdeswell et al.
1991; Hagen et al. 1993). For this reason, the number of
surge-type glaciers in Svalbard is likely to be under-
estimated in statistical analyses, which only include
observed surges. Nuth et al. (2007) found that most
glaciers on Spitsbergen (the largest of Svalbard’s islands)
had lost mass between 1936/38 and 1990, although
many had thickened in their upper parts, possibly
reflecting ice build-up during quiescent periods following
surges. Recent patterns of mass displacement determined
from aerial photographs and satellite imagery indicate
that ‘‘partial surges’’ (affecting only the upper parts of
glaciers) are common in Svalbard (Sund et al. 2009).
Paulabreen (77842’ N, 17824’ E) is a tidewater
glacier calving into Rindersbukta, inner Van Mijenfjorden
(Fig. 1). The glacier is confluent with Bakaninbreen,
which last surged (independently of Paulabreen) in
19851995 (Murray et al. 2000; Benn et al. 2009). Until
recently, Bakaninbreen shared a calving front with
Paulabreen, but due to lateral displacement of Bakaninb-
reen during the 200305 surge of Paulabreen, the former
now terminates on land. In the early 20th century,
Valla
˚krabreen, Scheelebreen and Ragna-Mariebreen
were major tributaries of Paulabreen, but today they are
independent glaciers that terminate on land (Ottesen
et al. 2008). Paulabreen, together with all tributaries
and Bakaninbreen, covers an area of 141.8 km
2
as
measured from an Advanced Spaceborne Thermal Emis-
sion (ASTER) image from 2005. Taken separately, Paula-
breen is 64.6 km
2
in area and 16 km long. Skobreen is a
tributary of Paulabreen, with an area of 18.2 km
2
and
a length of 8 km (Hagen et al. 1993). The equilibrium
line altitudes (ELAs) of Skobreen and Paulabreen were
estimated to be 290 and 330 m a.s.l., respectively by Hagen
et al. (1993). Mean annual air temperature is 5.48C
(19972006) and precipitation is on average 244 mm/yr
(19952002) at the coal mine Sveagruva, 18 km north-
west of the front of Paulabreen.
The bedrock of the Paulabreen catchment consists of
shales, siltstones and sandstones of Cretaceous to early
Tertiary age. The bedrock weathers and erodes easily and
the mountain slopes have large scree aprons covering
Fig. 1 Overview of the catchment. Two previous glacier-front positions
as well as the position reached by the 200305 surge are drawn. The
position of the RDC365 camera used for the time-lapse movie is shown.
Map basis: Advanced Spaceborne Thermal Emission (ASTER) image
taken on 24 July 2003.
A surge of the glaciers SkobreenPaulabreen, Svalbard L. Kristensen & D.I. Benn
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(page number not for citation purpose) Citation: Polar Research 2012, 31, 11106, http://dx.doi.org/10.3402/polar.v31i0.11106
their lower parts. The geology is important for surge
behaviour in Svalbard. Hamilton and Dowdeswell (1996)
and Jiskoot et al. (2000) showed that a sedimentary
lithology, in particular shale/mudstone as found in this
area, significantly increases the probability that a glacier
will be of surge type.
Four tributaries of Paulabreen (Skobreen, Sokkbreen,
Peisbreen and Ragna-Mariebreen) had arcuate frontal
moraines at their confluences with the main glacier
before the recent surge (Fig. 1). This contrasts with the
tributaries Knoppbreen, Nataschabreen and Bakanin-
breen, which form separate flow-units to Paulabreen as
indicated by medial moraines starting at the confluences
and extending to the glacier front. Aerial photographs
from 1936, 1956 and 1990 show that this pattern has
persisted since at least 1936.
The Holocene maximum position of Paulabreen is
located 25 km from the present glacier front and dates
to around 1300 AD (Punning et al. 1976; Rowan et al.
1982; Hald et al. 2001; Kristensen et al. 2009). The
moraines record one of the largest Little Ice Age advances
(and subsequent retreat) of any Svalbard glacier (De Geer
1919). In 1898, the front was located near the mouth of
Rindersbukta (Kjellstro
¨m 1901) (Fig. 1), then retreated
ca. 10 km until 2003. The 200305 surge of Paulabreen
then caused a frontal advance of 1.9 km (Ottesen et al.
2008). Despite the overall retreat, there is evidence that
Scheelebreen, Valla
˚krebreen and Ragna-Mariebreen
surged and advanced independently around 19191925
(De Geer 1919; Co
¨ster 1925). As noted above, Bakaninb-
reen surged from 1985 to 1995, but the surge terminated
before reaching the front and caused no advance. In a
series of papers (Porter et al. 1997; Murray et al. 1998;
Murray et al. 2000; Fowler et al. 2001; Murray & Porter
2001), it was shown that downglacier propagation of the
surge front was associated with thawing of the glacier
bed, and that flow acceleration reflected enhanced basal
motion over a thin layer of unfrozen basal till.
Methods
Time-lapse movie
A time-lapse camera was placed to the south-west of
Paulabreen on 28 April 2005 (Figs. 1, 2). The camera faced
eastnorth-east (0678) with the glacier front near the
centre of the image. By early July the front had advanced
out of view, and when the camera was visited on 16
August 2005 it was moved ca. 32 m uphill and turned
northwards (to 0258) to have the front in view again. The
distance to the glacier was ca. 1 km in the beginning but
was reduced to ca. 500 m as the glacier advanced.
The camera was an RDC-365 unit consisting of a
CX6200 digital camera (Kodak, Rochester, NY, USA),
built into a water-proof box with a time-lapse controller
and a solar panel by MetSupport (Roskilde, Denmark).
The image resolution is 16321232 pixels. The camera
was programmed to take one picture per day at 12.00
(local time) with a date-stamp. The RDC365 was mounted
on a small bench on the slope overlooking the glacier, on
one of the only places free of snow at the time of
installation. Later, it was observed that the whole slope
was ice-cored and rather unstable, which explains the
slight movement of the camera seen in the movie,
particularly in the snow melting period.
From the record of the active phase of the surge
(29 April 2005 to 15 November 2005), 24 pictures were
omitted due to fog, six due to raindrops on the window,
14 due to snow on the window and five due to the polar
night darkness. The longest period of missing frames was
eight days. The camera failed to record images on 92 days
in the polar night as the battery failed (the pictures would
have shown nothing for most of the period in any case).
From 16 February to 22 July 2006, 116 pictures were
removed, leaving only 40 pictures documenting the
stagnation and initial down-wasting of the glacier.
The selected images were enhanced using Auto Smart
Fix in Adobe Photoshop Elements and the movie was
compiled using Windows Movie Maker.
Photographs and ASTER images
The geometric evolution of the glacier during and follow-
ing the surge is documented using oblique aerial photo-
graphs taken on three occasions (8 August 2003,
26 September 2005 and 18 June 2007). In addition,
Fig. 2 Placing the time-lapse camera on 28 April 2005. Photographer:
Anne-Marie LeBlanc.
L. Kristensen & D.I. Benn A surge of the glaciers SkobreenPaulabreen, Svalbard
Citation: Polar Research 2012, 31, 11106, http://dx.doi.org/10.3402/polar.v31i0.11106 3
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ground-based photographs of the glacier front were taken
on various dates during spring 2005. We also mapped
visible surface features such as medial moraines and
moraine loops on satellite images and vertical aerial pho-
tographs. Three ASTER images (15 m resolution 1B VNIR,
bands 1, 2 and 3N) from different stages of the surge (24
July 2003, 23 July 2005 and 4 August 2008) were used.
The aerial photograph from 1990 (NP 1:50.000-S90
6826) was georeferenced by control points from a 2003
ASTER image using the spline transformation function
(‘‘rubber-sheeting’’) in ArcGIS. This transformation was
applied because the high mountains created distortion on
the image, which was taken at a low altitude compared to
the satellite image. In areas with few control points, such
as the glacier surfaces, the resulting rectified image most
likely contains inaccuracies of up to a few tens of metres.
These errors, however, are one or two orders of magni-
tude smaller than the displacements of interest, and
therefore do not significantly affect our results.
Data presentation and interpretation
The time-lapse movie
The images we include in this movie show the surge
advance of Paulabreen and the early part of the quiescent
period following surge termination. The movie shows
intensely crevassed ice at the advancing frontal and lateral
margins, behind which the glacier surface behaves like a
coherent block. Behind the surge front, therefore, glacier
motion appears to occur almost entirely by basal motion
(sliding and/or till deformation), with little deformation
of the overlying ice. This is consistent with the idea that
rapid motion during surges is facilitated by trapped,
pressurized water at the bed, and that basal drag is very
small. The driving stress arising from the downslope com-
ponent of the glacier’s weight appears to be largely sup-
ported at the glacier margins, where large stress gradients
result in intense deformation and fracture of the ice.
The land-based part of the glacier advanced across ice-
cored terrain that was mantled with a thin sediment
cover. From around 10 July 2005, the proglacial buried
ice on the right of the field of view can be seen to thicken
as the surge front comes closer, consistent with horizon-
tal shortening in response to compressive stresses trans-
ferred from the advancing glacier. From 24 July 2005, the
proglacial ice is dislocated along a succession of low-angle
fractures, and slabs are thrust ahead of the surge front
before being progressively over-ridden and incorporated
into the glacier. The movie illustrates the complexity of
deformation patterns in the zone of intense compression
near the glacier margin.
Following re-orientation of the camera on 16 August,
there is little evidence of deformation or dislocation of the
glacier foreland. This partly reflects the fact that the glacier
margin was obscured by foreland topography. The glacier
front forms a vertical calving face, and calving losses
partially offset the advance of the ice margin in this area.
The vertical ice front contrasts with the sloping, broken-
up glacier front seen prior to mid-July, when sea ice
remained in the fjord. This contrast indicates that calving
was suppressed in winter, possibly by the presence of sea
ice in the fjord or cessation of surface melting and water
input to crevasses (see Vieli et al. 2002; Nick et al. 2010).
The last image of 2005 is for 15 November. The sequence
resumes on 16 February 2006, when the glacier terminus
is a short distance beyond the November position. Only
minor forward motion of the ice is apparent in the 2006
images, indicating that surge termination occurred during
the months of darkness, probably in late November or
early December.
Evolution of Skobreen
Paulabreen during the
surge
The geometric evolution of SkobreenPaulabreen is
summarized in Fig. 3, which shows the location of the
ice front and medial moraines on the glacier surface
Fig. 3 Development of the surge illustrated by the progressive
displacement of medial moraines and end moraine loops as well as
the glacier-front positions. The illustration is based on the following
images: NP1990 1:50.000 (black), Advanced Spaceborne Thermal
Emission (ASTER) 24 July 2003 (blue), ASTER 23 July 2005 (green) and
ASTER 4 August 2008 (red).
A surge of the glaciers SkobreenPaulabreen, Svalbard L. Kristensen & D.I. Benn
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in 1990, 2003, 2005 and 2008. The surge was clearly in
progress by the summer of 2003. The moraine loop of
Skobreen extends farther out into Paulabreen than in
1990, and the upper trunk of Skobreen and tributary
niches were traversed by numerous transverse crevasses
(Fig. 4a). Crevasses in the upper part of Skobreen can be
very clearly seen in oblique aerial photographs taken on
8 August 2003 (Fig. 5). Approximately 700 m upstream
Fig. 4 Two Advanced Spaceborne Thermal Emission (ASTER) images showing Skobreen and most of Paulabreen showing the change in the crevasse
pattern: (a) the early surge phase, 24 July 2003; (b) the full surge stage, 23 July 2005.
Fig. 5 Two oblique photographs on 8 August 2003, during the early surge stage: (a) most of Skobreen; (b) a major part of the catchment. Both
photographs clearly show a surge bulge at the lower end of Skobreen. Photographer: Tavi Murray.
L. Kristensen & D.I. Benn A surge of the glaciers SkobreenPaulabreen, Svalbard
Citation: Polar Research 2012, 31, 11106, http://dx.doi.org/10.3402/polar.v31i0.11106 5
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of the moraine loop of Skobreen, a pronounced bulge can
be seen, traversed by longitudinal crevasses indicative of
compressive flow. The glacier between the bulge and the
moraine loop was deformed into a series of arcuate
waves, resembling ogives (see Waddington 1986). The
ice in the margins of the main trunk was brecciated.
There were no indications of activation of Paulabreen,
although the moraine-loop of Skobreen had moved ca.
300 m into the trunk of Paulabreen between 1990 and
2003. These observations are consistent with patterns of
elevation change measured from digital elevation models
by Sund et al. (2009), which showed ‘‘drawdown’’ of ice
in the upper part of Skobreen, and marked thickening of
its lower part. The date of surge initiation is not known,
although Sund (2006) argued that extensional crevasses
had begun to form in the upper basin as early as 1990.
Between summer 2003 and spring 2005, the surge
propagated downglacier and had affected most of the
lower tongue of Paulabreen. On 2 April 2005, we ob-
served that the south-west side of the glacier was heavily
crevassed and brecciated. Sea ice was bulldozed in front
of the glacier (Fig. 6) and continuous cracking noises
indicated high activity. However, the north-east part of
the glacier front was undisturbed, which suggests that we
arrived soon after the surge front reached the glacier
terminus. Fig. 7 shows the boundary between surging
and non-surging ice in mid-April 2005.
By 23 July 2005, the surge had affected all of Skobreen
and the entire width of Paulabreen (Fig. 4b). The
moraine loop of Sokkbreen had moved 1300 m down-
glacier. The medial moraine between Paulabreen and
Bakaninbreen was pushed obliquely downglacier, and its
lower part had been displaced several hundreds of metres
to the right (Fig. 3). The front had advanced by up to
1400 m. The length of the combined moraine-loop of
SkobreenPaulabreen increased from 3770 m (2003) to
5460 m (2005), probably indicating both shearing and
extension of the ice along this line.
The time-lapse movie shows that the surge ended in
the dark season of 200506, but the next cloud-free
ASTER image is from 4 August 2008. Moraine loops and
other debris features on the surface were located 1300 to
1500 m downstream and ca. 200 m laterally compared
with 23 July 2005. The SkobreenPaulabreen loop
became 700 m longer (to 6155 m), signifying further
extension along its line. The front had advanced between
200 and 400 m, although this must be less than the total
ice displacement because some calving occurred after
stagnation of the front. The average velocity in the main
trunk during the entire surge was 3.2 m/day assuming an
onset of the surge of Paulabreen of 24 July 2003 and a
termination in December 2005. It is important to note
that the surge front (the boundary between surging and
non-surging ice) must have travelled downglacier con-
siderably faster than this, as has been observed at other
surging glaciers (e.g., Raymond et al. 1987; Murray et al.
2000; Frappe & Clarke 2007).
Oblique aerial photographs taken in September 2005
show the morphological effects of the surge on the glacier
(Fig. 8). By that time, a large volume of ice had been
transported from upper Skobreen (the reservoir area)
into a lower receiving area. Remnants of ice left stranded
on the walls of the Skobreen cirque after the surge show
drawdown of at least 50 m over large areas. Almost the
Fig. 6 The surging glacier advances into the fjord Rindersbukta,
deforming the sea ice, in this photograph taken on 2 April 2005. Notice
the chaotic brecciated glacier ice. Photographer: Anne-Marie LeBlanc.
Fig. 7 The front of PaulabreenBakaninbreen on 14 April 2005. In the spring of 2005, the surge had only reached the south-western half of the front.
A surge of the glaciers SkobreenPaulabreen, Svalbard L. Kristensen & D.I. Benn
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entire catchment of Skobreen was active in the surge,
with the exception of a series of small niches around the
cirque headwalls. Even in these areas, however, trans-
verse crevassing indicates ice drawdown in response to
lowering of the main glacier (Fig. 9). In the receiving
area, the zone of most intense crevassing was around the
margins of the surging part of the glacier, whereas a large
part of Paulabreen behind the surge front was relatively
uncrevassed. This suggests that much of the glacier was
moving by plug flow over a weak substrate, consistent
with the flow pattern shown in the time-lapse movie.
Much of the stress exerted by this part of the glacier
appears to have been supported around the margins,
resulting in intense compression and fracturing.
Summary and conclusions
During 2003 and 2005 Skobreen and the lower part of
Paulabreen, Svalbard, experienced a major surge. ASTER
images from different stages of the surge together with an
aerial photograph before the onset of the surge were used
to evaluate the surge progression. The surge initiated in
Skobreen, and propagated downglacier into Paulabreen
eventually resulting in an advance of the glacier into
the fjord. The medial moraines of Paulabreen were pro-
gressively displaced obliquely downglacier, with a lateral
displacement of several hundreds of metres. Ice was
displaced a maximum of 2800 m downstream, measured
from displacement of debris surface features, giving an
average ice velocity of 3.2 m/day. The front advanced less
than the total ice displacement (13001800 m), as calving
occurred during the surge. The evidence for plug flow
suggests that the high velocities were the result of basal
Fig. 8 SkobreenPaulabreen during and following the surge. (a) The lower part of Paulabreen, viewed towards the south on 26 September 2005.
Skobreen occupies the cirque in the upper middle part of the photograph, and the boundary between surging and non-surging ice on Paulabreen is
visible on the upper left. (b) The surge front at the south-west margin of Paulabreen, 26 September 2005. Note the chaotically crevassed ice near the
glacier front, behind which the ice is relatively uncrevassed. In the foreground of the photograph is a crevassed forebulge formed of old, buried glacier
ice. (c) View over Paulabreen into Skobreen, 26 September 2005. (d) Remnant ice stranded above Skobreen after surge termination, 18 June 2007. The
ice cliff is ca. 50 m high.
Fig. 9 Photograph taken on 18 June 2007 towards the south-west
showing most of Skobreen after the surge. The majority of the glacier is
covered with transverse crevasses, including the niches to the left in the
picture. Note the substantial down-draw on either side of the main
trunk. Towards the bottom in the picture longitudinal crevasses can be
seen.
L. Kristensen & D.I. Benn A surge of the glaciers SkobreenPaulabreen, Svalbard
Citation: Polar Research 2012, 31, 11106, http://dx.doi.org/10.3402/polar.v31i0.11106 7
(page number not for citation purpose)
motion (sliding and/or till deformation) facilitated by
pressurized water at the bed.
A time-lapse movie (see Supplementary File) captured
the advance of the frontal part of the glacier, and
dramatically illustrates glacier dynamic processes in an
accessible way. The movie documents a range of pro-
cesses such as a plug like flow of the glacier, proglacial
thrusting, incorporation of old, dead ice at the margin
and calving into the fjord. In our experience, the movie
provides a powerful resource for teaching and inspiring
students, and for communicating the fascination of
glacier science to a wider public.
Acknowledgements
We kindly acknowledge the following people and in-
stitutions: Svalbard Villmarkssenter, a local tour company
that drew our attention to the surge of Paulabreen. Store
Norske Spitsbergen Kulkompani who funded the camera
and provided logistical support. The University Centre in
Svalbard (UNIS) provided funding and logistical support,
and Lars Grande helped secure funding for the camera
system. Anne-Marie LeBlanc, Alex Wolfe, Ole Humlum,
Ruth Mottram, Lars Grande, Fabrice Caline and various
student groups at UNIS helped in the field. The photo-
graphs in Fig. 5 were kindly provided by Tavi Murray.
The ASTER images were obtained from the Land
Processes Distributed Active Archive Centre of the US
National Aeronautics and Space Administration. The
1990 aerial photograph (Fig. 3) is used with permission
from the Norwegian Polar Institute.
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... However, researchers have also found that glaciers of similar scale differ greatly in their movement and retreat under the same climatic conditions (Xiao et al., 2007;Snehmani et al., 2014;Kingslake et al., 2016;Melkonian et al., 2016;Wu et al., 2016b;Zhen et al., 2018a;He et al., 2019;Zhen et al., 2019a). Many large glaciers undergo surges and advance quickly under different climate backgrounds (Kristensen and Benn, 2012;Aster, 2019); do phenomena such as surges also exist for small glaciers? Although conventional observations can provide some explanations for the dynamic mechanism of glaciers, for a fluid as complex as glacier, this approach is far from sufficient. ...
... The basic glacial characteristics indicate that the elevation distribution and the average slope of SG3 and SG4 were similar; the maximum thicknesses of the two glaciers were 65 m and 63 m, respectively, and glacial thickness is the primary factor determining velocity. In addition, there might be two causes for the increase of ice velocity: one was the decrease of ice body viscosity caused by the increase of temperature, and the other was glacier surge caused by rapid sliding after a peak in basal water pressure was reached (Jay-Allemand et al., 2011;Quincey et al., 2011;Kristensen and Benn, 2012). Both reasons for the increase in ice velocity were caused by climatic warming. ...
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As a climate-sensitive region, the glacier on Qilian Mountain is changing rapidly, and climate change can rapidly increase glacier flow instabilities through movement and ablation. We used the thermo-mechanically-coupled-with-full-Stokes code with the Elmer method to perform a steady-state diagnostic simulation of the Shuiguan River Glacier No. 3 (SG3) in the eastern Qilian Mountains, and to predict and analyze future changes of the glacier in combination with historical elevation data. The results showed that the average ice temperature was above −1.5 °C, that the hydrological process inside and under the ice was complex, and that the high ice temperature at the bottom would make the glacier fragile in the future. Because of the small thickness of the glacier and the small stress in the ice, the stress of the ice flow caused no great damage to the glacier. The development of cracks and melting holes under the ice was mainly caused by the melting of the glacier. Prognostic simulation under two climate models (RCP 4.5 and RCP 8.5) revealed that the area of SG3 changed evenly at first, and then retreated at an accelerated rate, whereas the volume consistently presented a state of accelerated reduction. Although our study confirmed that climatic warming was the main reason for glacial retreat, it was also found that the altitude of the glacier, the topography of the bedrock under the ice and the accumulation area would greatly affect the response of the glacier to climatic change. For these reasons, our study also profoundly elucidated why different glaciers with the same scale and under the same climatic conditions could exhibit different changes in area and terminal position.
... Glacial surges are dramatic events of rapid ice flow following the culmination of ice build-up (Benn & Evans 2010;Kristensen & Benn 2012;Sund et al. 2014) that leave behind conspicuous individual landforms and landform assemblages (Sletten et al. 2001;Christoffersen et al. 2005;Ottesen et al. 2008;Flink et al. 2015;Streuff et al. 2015;Farnsworth et al. 2016). Most investigations of glacier surging have focused on glacier dynamics (Kjaer et al. 2006) and landsystem models diagnostic of former surge-type glaciers (Evans & Rea 2003;Benediktsson et al. 2008;Benn & Evans 2010;Ing olfsson et al. 2016). ...
... This commenced in Skobreen, before propagating into the lower part of Paulabreen. The Skobreen ice margin advanced some 2800 m while Paulabreen advanced only 1300 m due to calving along the tidewater margin (Kristensen & Benn 2012). ...
Article
A prominent thrust-moraine system formed in the inner van Mijenfjorden, Svalbard, during a surge event in a tributary fjord, creating a large temporary lake. Based on geomorphological, sedimentological, stratigraphical and chronological data, the lake began to form shortly after 648–551 cal. a BP. At its maximum, the lake covered an estimated area of 77 km2 with a water volume of 1.2 km3. Lake sediment up to 80 cm thick was rapidly deposited on top of terrestrial and marine sediments. At its maximum extent, the short-lived lake was the largest of any known Holocene lake in Svalbard. Modern river discharge would fill the lake to its highest shoreline at 23 m a.s.l. in only one season. Drainage was stepwise, as evidenced by four shorelines and abandoned drainage channels. This study has taken advantage of a unique suite of data available for such an ice-dammed lake. The results demonstrate the power of a multidisciplinary approach for recognizing lake events in the geological record, which is essential given the low preservation potential of such sediments. http://onlinelibrary.wiley.com/doi/10.1111/bor.12302/full
... Luckman and others, 2002;Sund and others, 2014;Sevestre and others, 2018;Benn and others, 2019). Gradual slowdowns are typical of polythermal glaciers in Svalbard (though not all, see Kristensen and Benn, 2012), and may reflect the removal of hydraulic barriers during surge-front advance rather than a drainage system switch. Simulation of these effects will require a spatial treatment of basal hydrology. ...
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We present the first general theory of glacier surging that includes both temperate and polythermal glacier surges, based on coupled mass and enthalpy budgets. Enthalpy (in the form of thermal energy and water) is gained at the glacier bed from geothermal heating plus frictional heating (expenditure of potential energy) as a consequence of ice flow. Enthalpy losses occur by conduction and loss of meltwater from the system. Because enthalpy directly impacts flow speeds, mass and enthalpy budgets must simultaneously balance if a glacier is to maintain a steady flow. If not, glaciers undergo out-of-phase mass and enthalpy cycles, manifest as quiescent and surge phases. We illustrate the theory using a lumped element model, which parameterizes key thermodynamic and hydrological processes, including surface-to-bed drainage and distributed and channelized drainage systems. Model output exhibits many of the observed characteristics of polythermal and temperate glacier surges, including the association of surging behaviour with particular combinations of climate (precipitation, temperature), geometry (length, slope) and bed properties (hydraulic conductivity). Enthalpy balance theory explains a broad spectrum of observed surging behaviour in a single framework, and offers an answer to the wider question of why the majority of glaciers do not surge.
... Even though Hansbreen is among the best-studied glaciers in Svalbard, it remains unsolved whether or not it is a surge-type glacier. The latter are characterised by non-climate-related increase of the flow rate by at least an order of magnitude, which often results in glacier-front advance (Jania, 1997;Kristensen & Benn, 2012). There is no historical evidence of surging of Hansbreen (Błaszczyk et al., 2013). ...
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A 1:10,000 scale bathymetric map as well as 1:20,000 scale backscattering and geomorphological maps of two bays Isbjørnhamna and Hansbukta in the Hornsund fjord (Spitsbergen) present the submarine relief that was primarily formed during and after the retreat of the Hansbreen tidewater glacier. Geomorphological mapping was performed using multibeam bathymetric data and seismoacoustic profiling. The identified landforms include two types of transverse ridges interpreted as terminal and annual moraines, flat areas that are depressions filled with glaciomarine sediments, iceberg-generated pits and ploughmarks, pockmarks and fields of megaripples. Most of the identified landforms are genetically related to the retreat of Hansbreen since the termination of the Little Ice Age at the beginning of the twentieth century. Although Hansbreen has been speculated to be a surge-type glacier, no evidence of surging was identified in the submarine landform assemblage, which is in accordance with the absence of historically documented surges for that period.
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Calving is an important process in glacier systems terminating in the ocean, and more observations are needed to improve our understanding of the undergoing processes and parameterize calving in larger-scale models. Time-lapse cameras are good tools for monitoring calving fronts of glaciers and they have been used widely where conditions are favourable. However, automatic image analysis to detect and calculate the size of calving events has not been developed so far. Here, we present a method that fills this gap using image analysis tools. First, the calving front is segmented. Second, changes between two images are detected and a mask is produced to delimit the calving event. Third, we calculate the area given the front and camera positions as well as camera characteristics. To illustrate our method, we analyse two image time series from two cameras placed at different locations in 2014 and 2015 and compare the automatic detection results to a manual detection. We find a good match when the weather is favourable, but the method fails with dense fog or high illumination conditions. Furthermore, results show that calving events are more likely to occur (i) close to where subglacial meltwater plumes have been observed to rise at the front and (ii) close to one another.
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Glacier flow instabilities can rapidly increase sea level through enhanced ice discharge. Surge-type glacier accelerations often occur with a decadal to centennial cyclicity suggesting internal mechanisms responsible. Recently, many surging tidewater glaciers around the Arctic Barents Sea region question whether external forces such as climate can trigger dynamic instabilities. Here, we identify a mechanism in which climate change can instigate surges of Arctic tidewater glaciers. Using satellite and seismic remote sensing observations combined with three-dimensional thermo-mechanical modeling of the January 2009 collapse of the Nathorst Glacier System (NGS) in Svalbard, we show that an underlying condition for instability was basal freezing and associated friction increase under the glacier tongue. In contrast, continued basal sliding further upstream increased driving stresses until eventual and sudden till failure under the tongue. The instability propagated rapidly up-glacier, mobilizing the entire 450 km2 glacier basin over a few days as the till entered an unstable friction regime. Enhanced mass loss during and after the collapse (5–7 fold compared to pre-collapse mass losses) combined with regionally rising equilibrium line altitudes strongly limit mass replenishment of the glacier, suggesting irreversible consequences. Climate plays a paradoxical role as cold glacier thinning and retreat promote basal freezing which increases friction at the tongue by stabilizing an efficient basal drainage system. However, with some of the most intense atmospheric warming on Earth occurring in the Arctic, increased melt water can reduce till strength under tidewater glacier tongues to orchestrate a temporal clustering of surges at decadal timescales, such as those observed in Svalbard at the end of the Little Ice Age. Consequently, basal terminus freezing promotes a dynamic vulnerability to climate change that may be present in many Arctic tidewater glaciers.
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Sedimentological, morphological and chronological studies of the Van Mijenfjorden region, Svalbard suggest numerous glacial advances seen in terrestrial and marine archives spanning from the Late Weichselian to the Little Ice Age. Only one ice-marginal deposit from the retreat phase of the fjord glacier is found along the entire fjord system. The deposit is located at a topographically controlled position near a bedrock threshold at the mouth of the fjord. Glacial records from tributary valleys and fjords correspond to varying sizes and styles of ice flow related to the deglaciation of the area during the Lateglacial and early Holocene as well as the regrowth of glacier systems during the early Holocene, the Neoglacial and the Little Ice Age. During the Younger Dryas, as the Van Mijen-fjord glacier retreated, a glacier advance took place in a southern tributary, probably as a dynamic response to the retreat in the fjord. Another glacier advance from a northern tributary valley took place during the early Holocene. This glacier advance extended to a position well outside the Little Ice Age (LIA) margins during a period in time when marine proxies suggest warm regional fjords. A Neoglacial glacier advance is identified in a third and inner tributary which also extends further than the subsequent LIA maximum. The Paula glacier system in the inner part of the fjord surged at least five times in the last 650 years, with each subsequent surge advance exhibiting less extensive maximum than the previous, resulting in an overall decrease in mass of the Paula glacier.
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This paper presents a Glacier Termini Tracking (GTT) toolbox for the two-dimensional analysis of glacier-terminus position changes. The input consists of a vector layer with several termini lines relating to the same glacier at different times. The output layers allow analyses to be conducted of glacier-terminus retreats, changes in retreats over time and along the ice face, and glacier-terminus fluctuations over time. The application of three tools from the toolbox is demonstrated via the analysis of eight glacier-terminus retreats and fluctuations at the Hornsund fjord in south Svalbard. It is proposed that this toolbox may also be useful in the study of other line features that change over time, like coastlines and rivers. The toolbox has been coded in Python and runs via ArcGIS.
Thesis
Abstract This thesis presents a reconstruction of the late Weichselian, deglacial and Holocene glacial history of the Svalbard fjords, focusing on eastern Svalbard. The study is based on high-resolution multibeam data, shallow acoustic (chirp) data, marine sediment cores, historical maps and aerial- satellite images. During the Last Glacial Maximum the Svalbard Barents Sea ice sheet reached the shelf edge around Svalbard and was drained by large ice streams along its western and northern margins, located in the same areas as the present day cross-shelf troughs. In northeastern Svalbard, fastflowing ice converged into the Hinlopen Strait ice stream from the surrounding fjords. Submarine landforms indicate that ice flow velocities increased as ice flowed from the inner- to the outer fjords and the shelf. The deglaciation from the northeastern shelf edge proceeded rapidly by ice lift-off in the troughs and deeper parts of the fjords, whereas the shallower areas experienced slower retreat with minor re-advances. The inner fjords around Nordaustlandet were ice free prior to 11.3-10.5 ka BP years. During early- to mid-Holocene tidewater glaciers in Mohnbukta and Vaigattbogen experienced at least one surge-type advance. These pre-Little Ice Age surges differentiate the east coast glaciers from the west coast glaciers. The early Holocene advance in Mohnbukta has been attributed to rapid climatic and environmental change at the end of the deglaciation, leading to dynamic disequilibrium and an environmentally induced jump into surge-mode. This suggests a more dynamic Holocene glacial history in Svalbard than previously stated, also indicating that the role of climate is more important in the evolution of general surge patterns than previously presumed. Similarly, climatic and environmental changes at the end of the Little Ice Age could explain why many Svalbard glaciers, both on the west and east coasts surged in that time period. Today, the majority of Svalbard’s fjords accommodate tidewater glaciers, of which several have been recorded to surge. Commonly the glaciers have surged at least twice during the Holocene. The surging tidewater glacier landform assemblages share many similarities and can be used to identify past surges in the geological record. In this study the submarine morphology has been used to identify three new surge-type glaciers in Wahlenbergfjorden. The surge history of the Svalbard glaciers is diverse and even though the landform assemblages share many similarities, they all feature differences, suggesting that local conditions are important in the evolution of glacial surges.
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Bakaninbreen is a 17 km long surge-type glacier in southern Spitsbergen, Svalbard, which began surging between the springs of 1985 and 1986, forming a surge front where fast-moving surge ice meets non-surging ice. This surge front has propagated 6 km down-glacier over the period to 1995. Instruments known as “ploughmeters” were installed into the deformable sedimentary bed close to the surge front to assess mechanical conditions year-round. Forces experienced by ploughmeters located down-glacier of the surge front are generally lower than those recorded by a ploughmeter up-glacier of the surge front. Ploughmeters installed at the bed down-glacier of the surge front show initially low applied forces, followed by increasing applied forces. We interpret this increase in applied forcing as a late-active-phase motion event. Analysis of ploughmeter data allows calculation of the yield strength of basal sediments. Yield-strength estimates at Bakaninbreen are in the range 16.6–87.5 kPa. Comparison with estimates of basal shear stress suggests that sediments up-glacier of the surge front will be actively deforming, whereas there will be only limited deformation down-glacier of the surge front. Immediately down-glacier of the surge front, calculations indicate negligible basal shear stresses. Together with the deformation of sediment from up-glacier, this implies a build-up of sediment at the surge front, offering a potential explanation for the sediment-filled thrust faults outcropping on the surge front.
Article
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Bakaninbreen, Svalbard, started surging in 1985 and developed a steep surge front where fast-moving ice impinged on stagnant non-surging ice. This front, which was 20- 25 m high in 1985, became a steep and heavily crevassed feature about 60 m high. The surge continued through 1986-95. Annual surge-front propagation rate was 1.0 1.8 km a−1 during 1985-89; this rate dropped considerably during 1989 95 and the front became less steep. Front propagation occurred largely by longitudinal compression and vertical extension of the ice and the effects of over-riding appear minor. Ice velocities were slower than the average propagation rate of the front. The surge affected Bakaninbreen in four zones: (1) Upper region where extensive flow, fast propagation rates and negative vertical strain occurred, resulting in widespread crevassing and stranded blocks tens of metres above the post-surge ice surface, (2) Mid-glacier region where initial strong compression was associated with ice thickening which started before the arrivai of the surge front. Horizontal strain rates were very low but vertical strain rates were tip to 300 mmd−1. As (he front passed, the horizontal velocity increased and about 500 m behind it became extensive. Negative vertical strain and ice down-draw occurred as ice velocities dropped, (3) Surge front where ice velocity was high but vertical strain remained positive associated with compression. (4) Lower region below the iront where only compression occurred, resulting in the formation of a fore bulge, a thickening of the ice of up to 50 m above pre-surge levels. The fore bulge affected the whole 1.7 km below the, now halted, surge front. The glacier has not advanced, Bakaninbreen’s surge was characterized by a long active phase, approximately 10 years, low ice velocities and low basal shear stresses compared to glaciers in lower latitudes, and an indistinct surge termination.
Article
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Surging glaciers are common in Svalbard yet relatively few glaciers have been observed during a surge. This paper presents observations of the currently surging glacier Skobreen, in southern Spitsbergen. The study is based on examinations of new and archival photographs and maps. Skobreen, an 18 km 2 valley glacier terminating into the lower part of the glacier Paulabreen, has not been registered previously as a surging glacier. Skobreen experienced a build-up in its upper part, while there has been a lowering of the surface in the terminal region. Photographs from 1990 show incipient crevassing in the upper part. Photographs from 2003 show a slight advance of the terminus and marginal crevassing, indicating an initiation period of about 15 years for a surge of this glacier. In June 2005 transverse crevassing appeared in the upper part of the glacier, while the middle section moved as a block with strong shear margins and a pronounced drawdown of the ice surface. No traces of a surge front could be seen in the crevasse pattern. However, the crevasse pattern indicates an initiation area in the transition zone between the transverse crevassing in the upper part and the block of ice in the middle region.
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Geometric changes on a sample of Svalbard glaciers were studied using subtraction of repeat digital terrain models to determine early surge-stage dynamics. Changes in surface features were also analyzed. A number of new surges were found for glaciers not known to have surged previously. The surge development could be followed through three stages, of which the first two had not been previously described in Svalbard. The first two stages are mainly identified from glacier thickness changes and showed little visual evidence. In stage 1, initial surface lowering was found in the upper part of the glacier, followed by a thickening further downglacier in stage 2. Stage 3 represents the period of well-developed surge dynamics that is usually reported. Some surges ceased at stage 2 as a partial surge and never developed into a fully active surge. These partial surges could be misinterpreted as rapid response to climate change. The results of this study further support previous findings that the majority of Svalbard glaciers are of surge type.
Article
The geographical distribution of surge-type glaciers worldwide displays a remarkably non-random pattern. Surge-type glaciers tend to be concentrated in certain glacierized areas and to be completely absent in others. This observation suggests that special conditions are required for surges to occur. However, the factors controlling the spatial occurrence of surge-type behaviour are not known. To investigate this problem we performed probability statistical analysis on a sample population of 615 glaciers in Svalbard. The probability that a glacier in the sample population is surge-type is 36.4%. Within the sampled area there is a spatial variation in the concentration of surge-type glaciers. Several geometric and environmental factors associated with glaciers in the sample population were measured and tested to determine if they are related to the probability of surging. Of the geometric factors tested (length, slope, elevation, orientation and presence or absence of tributaries), only glacier length is related to surging, with surge probability increasing with increasing length. Elevated probabilities of surging were also found for glaciers associated with sedimentary subglacial rocks and sub-polar thermal regimes. The distributions of related factors were used to predict the spatial distribution of surge-type glaciers. However, in each case the individual factors were unable to reproduce the observed pattern of surge-type glacier distribution.
Article
Many glaciers in Svalbard and in other glacierized areas of the world are known to surge. However, the time series of observations required to assess the duration of fast motion is very restricted. Data on active-phase duration in Svalbard come from aerial photographs, satellite imagery, field surveys and airborne reconnaissance. Evidence on surge duration is available for eight Svalbard ice masses varying from 3 to 1250 km2. Worldwide, active-phase duration is recorded for less than 50 glaciers. Few observations are available on high polar ice masses. The duration of the active phase is significantly longer for Svalbard glaciers than for surge-type glaciers in other areas from which data are available. In Svalbard, the active phase may last from 3 to 10 years. By contrast, a surge duration of 1–2 years is more typical of ice masses in northwest North America, Iceland and the Pamirs. Ice velocities during the protracted active phase on Svalbard glaciers are considerably lower than those for many surge-type glaciers in these other regions. Mass is transferred down-glacier more slowly but over a considerably longer period. Svalbard surge-type glaciers do not exhibit the very abrupt termination of the active phase, over periods of a few days, observed for several Alaskan glaciers. The duration of the active phase in Svalbard is not dependent on parameters related to glacier size. The quiescent phase is also relatively long (50–500 years) for Svalbard ice masses. Detailed field monitoring of changing basal conditions through the surge cycle is required from surge-type glaciers in Svalbard in order to explain the significantly longer length of the active phase for glaciers in the archipelago, which may also typify other high polar ice masses. The finding that surge behaviour, in the form of active-phase duration, shows systematic differences between different regions and their environments has important implications for understanding the processes responsible for glacier surges.
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Wave ogives arise in a solution of the continuity equation by the method of characteristics. Steady ice flow is assumed. Ice velocity, channel width, and mass-balance functions combine to form a wave-excitation potential that yields the forcing function for wave ogives. This linear-systems formulation extends the ogive theory of Nye. Convolution of the temporal cumulative mass balance and spatial forcing functions gives the total wave pattern below an ice fall. Many ice falls do not generate ogives because the wave amplitude is modulated by a factor related to ice-fall length. The wave ogives at Austerdalsbreen, Norway, are due almost entirely to ice acceleration at the top of the ice-fall, i.e. the same zone that King and Lewis showed was responsible for forming Forbes bands.
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