Strongbreen Retreat, Fjord Expansion, Svalbard

Strongbreen is a glacier in Svalbard on the southern part of Spitsbergen draining east into the Kvalvagen Fjord. Blaszczyk et al’s (2009) analysis identified 163 Svalbard glaciers that are tidewater with the total length calving ice−cliffs at 860 km for the 2001-2006 period. They observed that 14 glaciers had retreated from the ocean to the land over the last 30–40 year period. One glacier they observed having separated from neighboring glaciers was Strongbreen, which they noted was retreating at a rate of approximately 40 m/year since the previous inventory. The glacier had been connected with the Kvalbreen and Perseibreen Glacier. They also identified this as a surging glacier with the last known surge in the 1870’s.
strong breen map
strongbreen place
Map from TopoSvalbard

Here we examine Landsat images from 1990. 2002, 2014 and a Digital Globe image from 2010, to identify changes in the glacier over the last 25 years, the colored arrows are in the same location in each image. In 1990 the glacier extended down fjord to the red arrow and yellow arrow on the south side and north side of Kvalvagen respectively. On the southern side the terminus is at Sergievskijfjellet. Kvalbreen at the pink arrow terminates nearly parallel with the northern shore of the fjord. At the blue arrow is the glacier junction with a very small glacial dammed lake between the glacier and the adjacent mountain. By 2002 a small fjord is beginning at the pink arrow where Kvalbreen terminates. Strongbreen on the southern side of the fjord has a much narrower connection to the peninsula at the red arrow and has retreated on the north side from the yellow arrow. By 2014 the glacier has retreated to the green arrow on the southern side of the fjord from the red arrow, a distance of 3.75 km in 24 years. On the northern side the glacier has retreated almost to the orange arrow a similar distance of 3.5-3.8 km. This is a retreat of 150 m/year for Strongbreen quite an acceleration. Kvalvagen has retreated 1 to 1.25 km up the newly developing fjord, a retreat of 1 km in 25 years, 40 m/year. The glacial dammed lake at the blue arrow has expanded. A better view of this lake is in the 2010 image, last one, indicating that the lake now is almost half the tributary glacier width. The expansion of this lake will lead to this tributary having a separate terminus and undermine the stability of the lower section of Strongbreen.

The lower portion of the glacier is largely uncrevassed indicating quite slow velocities. Blaszczyk et al (2009) report a velocity of less than 30 m/year from 2000-2006. The low slope, limited crevassing, expanding supraglacial lake all indicate continued retreat. It then seems likely the glacier will separate into two fjords with a southern and a northern arm. The only thing that could forestall the retreat for a brief period is a surge as happended on nearby Perseibreen in 2000 (Dowdeswell and Benham, 2003). The retreat of this glacier paralells that of other glaciers in southern Svalbard: Vasilievbreen, Olsokbreen, Hornbreen and Hambergbreen.

strongbreen 1990
1990 Landsat image

strongbreen 2002
2002 Landsat image

strongbreen 2014
2014 Landsat image

strongbreen image
2010 Digital Globe image posted in TopoSvalbard.

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Svitjodbreen Retreat, Northwest Svalbard

Svitjodbreen is a 10 km long tidewater outlet glacier in northwest Svalbard, Albert Land. The glacier drains north into Fugelfjorden, the highest elevation of the main glacier is 600 meters with a few neighboring peaks reaching 800 m, not very high. NW Svalbard is a region that has experienced extensive long term thinning from 1965 to 2007 (Nuth et al, 2010), with an average glacier wide thinning of 0.5 m/year and frontal thinning of over 1 m/year. nw svalbardjarlbreen overview copyThe retreat is similar to that of Southern Svalbard at Hornbreen and Hambergbreen and much faster than in Eastern Svalbard at Edgoya. Here we examine Landsat images from 1987, 2000 and 2011 and a Google Earth image from 2009. In each image there are four fixed points: Point A is on the south side of the ridge just south of Rissabreen. Point B is at a small peak, Hirdfjellet. Point C is at the beginning of the Skutelen Peninsula just south of Hirdfjellet and Point D is a small bedrock ridge. In 1987 the terminus extends across the 2 km wide fjord one kilometer north of the ridge on the west side of the glacier labelled A and extends directly across the fjord to Point B. Point D is 3 km behind the glacier front and Point C is 1.5 km from the ice front. By 2000 the western side of the terminus has retreated nearly 500 meters and the east side by Point B very little. In 2011 the terminus has retreated beyond the bedrock ridge at Point A and extends across the fjord to Point C. The bedrock Point D is now just 1.6 km from the glacier front. Jarlbreen has retreated 1200 to 1500 meters from 1987 to 2011, with most of the retreat occurring after 2000.

jarlbreen 1987

jarlbreen 2000
jarlbreen 2012
The front of the glacier is heavily crevassed indicating considerable calving activity. Google Earth refers to this glacier as Jarlbreen, but Jarlbreen is east of the Skutulen Peninsula. The ridge at Point D has expanded as the glacier has thinned. Oerlemans et al (2011) noted a similar retreat rate for Hansbreen. They further determined that calving losses were of the same magnitude as melting losses. jarlbreen ge

Retreat of Nannbreen, Svalbard

Nannbreen is a 5 km long land terminating glacier in southwest Svalbard. The glacier is just north of Hornsund. During the course of the 20th century Nannbreen retreated from its Little Ice Age moraine complex forming a new proglacial lake. The glacier ends at an elevation of 150 meters descending from 600 meters, the snowline in several Landsat images from the last decade has been 400-450 meters. By 2000 (first image below)the glacier had retreated 750 meters from the moraine complex and the glacier ended in a lake, that was over 500 meters long. In 2010 (second image below) the glacier had retreated out of the lake, 250 meters of retreat in 10 years, 1000 meters of retreat in the last century. Certainly the 21st century retreat rate is far above the average 20th century retreat rate. Most of the large glaciers in Svalbard are tidewater calving glaciers, such as the nearby Hansbreen, which retreated 400 meters from 2000-2005. Svalbard glaciers have been losing considerable volume, indicative of negative mass balance and glacier retreat. Nuth et al (2010) concluded that over the past 40 years for Svalbard ice loss is 9.71 ± 0.55 cubic kilometers/year. This is an average thinning of 0.36 meters/year for an annual contribution to global sea level rise of 0.026 mm yr.