Kangersuneq Qingordleq, Greenland Retreat Causes Separation

On October 18, 2016May 1, 2024 By mspeltoIn Greenland glacier retreat

Landsat comparison from 1999, 2001, 2013 and 2016 of Kangersuneq Qingordleq. Red arrow is 1999 terminus, yellow arrow is 2016 terminus. Purple dots mark the transient snowline and the purple arrow a detached tributary.

Kangersuneq Qingordleq is one of the most southerly tidewater glaciers in Greenland. It is a 15 km long glacier flowing from the mountains between Prince Christian Sound and Lindenow Fjord. It is more akin to an Alaskan tidewater outlet glacier than ice sheet fed Greenland outlet glaciers. Greenland tidewater outlet glaciers in this region have experienced substantial retreat since 1990, Weidick et al (2012) and Howat and Eddy (2011). Howat and Eddy (2011) examined 200 tidewater glaciers in Greenland from 2000 and 2010 observing that 191 had retreated, rapid retreat was observed in all sectors of the ice sheet. Moon and Joughin (2008) observed a synchronous ice sheet–wide increase in tidewater retreat from 2000–2006 versus 1992–2000, coincident with a 1.1°C increase in mean summer temperature. There was also an increased in sea surface temperature (Straneo et al, 2013). The retreat of glaciers in southern Greenland is changing the physical geography and hence physical oceanography of the fjords.

Here we examine Landsat imagery from 1999-2016 to identify recent behavior. In 1999 the glacier terminated at a narrow point in the fjord, red arrow. This location is also just beyond a junction with a tributary from the east. The fjord was just 600 m wide which would act as a pinning point restricting calving. It would not be surprising if fjord depth was also reduced here. By 2001 the glacier has retreated a short distance from the narrow point and is beginning to separate from the tributary. The transient snow line is at 950-1000 m. By 2005 the glacier had retreated 800 m and had fully separated from the eastern tributary, the ice front was 1 km wide. By 2013 the glacier has retreated into a section of the fjord that is 1.2 km wide and the transient snowline is at again at 950-1000 m. By 2016 the glacier has retreated 2.8 km since 1999. The transient snowline is 1000-1050 m in 2016, which is high enough to drive continued retreat. The fjord further widens to 1.4 km, 2.5 km behind the glacier front. This suggests that retreat will continue as there will be less sidewall stabilization. The glacier since 1999 has lost nearly 20% of its total length. To the northeast Qaleraliq has experienced a 3.2 km of its west arm and 1.2 km of its east arm from 1992 to 2012. To the northeast Tingmiarmiit Glacier retreat from 1999-2015 has led to complete separation of the western and northern tributary. The western tributary is the main glacier and has retreated 2.4 km and the northern tributary has retreated 2.2 km in the 16 year period. In the case of nearby Tasermiut Fjord retreat has led to fjord losing its tidewater connection.

Terminus of Kangersuneq Qingordleq in 2005 Google Earth image. Red arrow is 1999 terminus, yellow arrow is 2016 terminus.

Map of the region around Kangersuneq Qingordleq. Red arrow is 1999 terminus, yellow arrow is 2016 terminus.

2016 Field Season Results-North Cascade Glacier Climate Project

On October 14, 2016October 14, 2016 By mspeltoIn climate change glacier retreat, Glacier Observations, glaciers salmon

For Mount Baker, Washington the freezing level from January-April 20 was not as high as the record from 2015, but still was 400 m above the long term mean. April 1 snowpack at the key long term sites in the North Cascades was 8% above average. A warm spring altered this, with April being the warmest on record. The three-four weeks ahead of normal on June 10th, but three weeks behind 2015 record melt. The year was poised to be better than last year, but still bad for the glaciers. Fortunately summer turned out to be cooler, and ablation lagged. Average June-August temperatures were 0.5 F above the 1984-2016 mean and 3 F below the 2015 mean. The end result of our 33rd annual field season assessing glacier mass balance in the North Cascades quantifies this. Our Nooksack Indian Tribe partners again installed a weather and stream discharge station below Sholes Glacier.

The primary field team consisted of myself, 33rd year, Jill Pelto, grad student UMaine for the 8th year, Megan Pelto, Chicago based illustrator 2nd year, and Andrew Hollyday, Middlebury College. We were joined by Tom Hammond, NCCC President 13th year, Pete Durr, Mount Baker Ski Patrol, Taryn Black, UW grad student and Oliver Grah Nooksack Indian Tribe. The weather during the field season Aug. 1-17th was comparatively cool.

Mass Balance: Easton Glacier provides the greatest elevation range of observations. On Aug 2, 2016 the mean snow depth ranged from 0.75 m w.e. at 1800 m to 1.5 m w.e. at 2200 m and 3.0 m w.e. at 2500 m. Typically the gradient of snowpack increase is less than this. There was a sharp rise in accumulation above 2300 m. This is the result of the high freezing levels. The mass balances observed fit the pattern of a warm but wet winter. The high freezing levels left the lowest elevation glaciers Lower Curtis and Columbia Glacier with the most negative mass balance of approximately 1.5 m. The other six glaciers had negative balances of -0.6 to -1.2 m. This following on the losses of the last three years has left the glaciers with a net thinning of 6 m, which on glaciers averaging close to 50 m is a 12% volume loss in four years. We anticipate with that this winter will be cooler and next summer the glaciers happier. We will back to determine this.

Snowpack loss from Aug. 5-Sept. 22 is evident in the pictures below on Sholes Glacier. Detailed snow depth probing, 112 measurements, of the glacier on August 5th allows determination of ablation as the transient snow line traverses probing locations from Aug. 5. GPS locations were recorded along the edge of blue ice on each of the dates. Ablation during this period was 2.15 m.

Terminus Change: We measured terminus change at several glaciers and found that a combination of the 2015 record mass balance loss and early loss of snowcover from glacier snouts in 2016 led to considerable retreat since August 2015. The retreat was 25 m on Easton Glacier, 20 m on Columbia Glacier, 20 m on Daniels Glacier, Sholes Glacier 28 m, Rainbow Glacier 15 m, Lower Curtis Glacier 15 m. The main change at Lower Curtis Glacier was the vertical thinning, in 2014 the terminus was 41 m high, in 2016 the terminus seracs were 27 m high. The area loss of the glaciers will continue to lead to reduced glacier runoff. We continued to monitor daily flow below Sholes Glacier which allowed us to determine that in August 2016 45% of the flow of North Fork Nooksack River came from glacier runoff. This is turns has impacts for the late summer and fall salmon runs.

Shatter & Shudder Glacier Retreat, British Columbia Lakes Form

On October 11, 2016May 1, 2024 By mspeltoIn Canada glacier retreat, glacier climate change, Glacier Observations, Uncategorized

Red arrow is the 1985 terminus location and yellow arrow the 2016 terminus location. Note the formatiion of new lakes at end of both glaciers. Purple dots is the transient snowline in August of each year.

Shatter and Shudder Glacier are at the eastern end of the Spearhead Range in Garibaldi Provincial Park, British Columbia. Osborn et al (2007) mapped the Little Ice Age extent of the glaciers compared to the 1990’s margins indicating a retreat of 300 m for Shatter Glacier and 700 m for Shudder Glacier (see below). Koch et al (2009) identified the recession in area from 1928 to 1987 noting a 6% loss in Shatter Glacier and 22% loss for Shudder Glacier. Koch et al (2009) identify an 18% loss in area from 1987-2005, indicating considerable recent change in the Park. Here we use Landsat imagery from 1985-2016 to update glacier change.

In 1985 there are no lake at the terminus of either Shatter or Shudder Glacier. In 2002 a lake has formed at the terminus of Shudder Glacier, but not Shatter Glacier. In 2016 both glaciers have proglacial lakes that have formed, and the terminus of both glaciers have retreated from the lakes. This marks a retreat of 325 m on Shudder Glacier and 275 m on Shatter Glacier since 1985. Shudder Glacier retreated more rapidly in the first half of this period, while Shatter Glacier has experienced most of the retreat since 2005.

On Shatter and Shudder Glacier In 1987 the late August image indicates the snowline is at 2040 m, in mid-August 2015 the snowline is at 2250 m. In late August of 2014 the snowline was at 2120 m. In mid-August 2016 the snowline is at 2080 m. The higher snowlines are an indicator of mass loss for these glaciers that in turn drives retreat. The region continues to experience significant loss in glacier area and development of many new alpine lakes with glacier retreat, five new lakes since 1987 just in this range with seven glaciers. Spearhead and Decker Glacier are two other glaciers in the range that have developed new lakes since 1987. Nearby Helm Glacier is faring even worse.

Landsat images from 1987, 2014 and 2015 indicating the transient snowline position at the purple dots on Shatter and Shudder Glacier.

Pink Arrows indicate five new alpine lakes that have developed since 1987 as Spearhead Range glaciers have retreated

Map of Spearhead Range glacier extent for LIA-Bold lines and 1987, light lines from Osborn et al (2007)

Findelengletscher, Switzerland Retreat & Hydrology Insights from David Collins

On October 3, 2016May 1, 2024 By mspeltoIn glacier climate change, switzerland glacier retreat

Landsat image comparison of Findelengletscher from 1988 to 2015. Red arrow indicating the 1988 terminus location and yellow arrow the 2015 terminus location. The purple arrows indicate two tributaries connected to the main glacier in 1988 and now disconnected.

Findelengletscher along with Gornergletscher drains the west side of the mountain ridge extending from Lyskamm to Monte Rosa, Cima di Jazzi and Strahlhorn in the Swiss Alps. It is the headwaters of the Matter Vispa. This glacier was also the favorite field location for David Collins, British Glaciologist/Hydrologist from University of Salford who passed away last week. David had a wit, persistence and insight that are worth remembering. This post examines both David’s findings reaching back to the 1970’s gained from a study of glaciers in this basin and changes of the glacier since 1988 as evident in Landsat images. Findelengletscher drains into the Vispa River which supports for hydropower project, with runoff diverted into two hydropower reservoirs, Mattmarksee operated by the Kraftwerke Mattmark producing 650 Gwh annually, and Lac de Dix operated by Grande Dixence that produces 2000 Gwh annually. There are two smaller run of river projects as well.

The Swiss Glacier Monitoring Network has monitored the terminus change of Findelengletscher since the 1890’s. The glacier advanced 225 m from 1979-1986, retreated 450 m from 1988-1999 and retreated 850 m from 1999-2015. This is illustrated above with the red arrow indicating the 1988 terminus location and the yellow arrow the 2015 terminus location. The purple arrows indicate two tributaries connected to the main glacier in 1988 and now disconnected. The more limited retreated from 1988-1999 is evident in images below. The retreat is driven by mass losses with Huss et al (2012) noted as 1 m/year in the alps from 2001-2011. The snowline has typically been above 3250 m too high for equilibrium in the last decade. Melt at the terminus has typically been 7-8 m (WGMS).

Collins (1979) in work funded through hydropower looked at the chemistry of glacier runoff and found that glacier meltwater emerging in the outlet stream was enriched in Calcium, Magnesium and Potassium in particular versus non-glacier runoff, this led to a much higher conductivity. Collins (1982) noted the reduction in streamflow below Gornergletscher from summer streamflow events that reduced ablation for up to a week after the event. Collins (1998) noted that a progressive rise of the transient snow line in summer increases the snow-free area, and hence the area of basin which rapidly responds to rainfall. Rainfall-induced floods are therefore most likely to be largest between mid-August and mid-September and in this period of warmer temperatures and higher snowlines. Collins (2002) Mean electrical conductivity of meltwater in 1998 was reduced by 40%. In the same 60 day period in 1998, however, solute flux was augmented by only 2% by comparison with 1979. Year-to-year climatic variations, reflected in discharge variability, strongly affect solute concentration in glacial meltwaters, but have limited impact on solute flux. Collins (2006) identified that in highly glacier covered basins, over 60%, year-to-year variations in runoff mimic mean May–September air temperature, rising in the warm 1940s, declining in the cool 1970s, and increasing by 50% during the warm dry 1990s/2000s. In basins with between 35–60% glacier cover, flow also increased into the 1980s, but declined through the 1990s/2000s. With less than 2% glacier cover, the pattern of runoff was inverse of temperature and followed precipitation, dipping in the 1940s, rising in the cool-wet late 1960s, and declining into the 1990s/2000s.. On large glaciers melting was enhanced in warm summers but reduction of overall ice area through glacier recession led to runoff in the warmest summer (2003) being lower than the previous peak discharge recorded in the second warmest year 1947. Collins (2008) examined records of discharge of rivers draining Alpine basins with between 0 and ∼70% ice cover, in the upper Aare and Rhône catchments, Switzerland, for the period 1894-2006 together with climatic data for 1866-2006 and found that glacier runoff had peaked in the late 1940s to early 1950s.

These observations have played out further with warming, retreat and more observations. Finger et al (2012) examine the impact of future warming on glacier runoff and hydropower in the region. They observe that total runoff generation for hydropower production will decrease during the 21st century by about one third due glacier retreat. This would result in a decrease in hydropower production after the middle of the 21st century to keep Mattmarksee full under current hydropower production. Farinotti et al (2011) noted that the timing of maximal annual runoff is projected to occur before 2050 in all basins and that the maximum daily discharge date is expected to occur earlier at a rate of ~4 days/decade. Farinotti et al (2016) further wondered if replacing the natural storage of glacier in the Alps could be done with more alpine storage behind dams.

Google Earth image indicating flow of the Findelengletscher.

Landsat image comparison of Findelengletscher from 1999 to 2016. Red arrow indicating the 1988 terminus location and yellow arrow the 2015 terminus location. The purple arrows indicate two tributaries connected to the main glacier in 1988 and now disconnected.

Terminus of Findelengletscher in Google Earth. The lower several hundred meters has limited crevasses, but is not particularly thin.

Storglombreen Glacier Loss, Norway

On September 28, 2016May 1, 2024 By mspeltoIn glacier climate change, Glacier Observations, Norway glacier retreat1 Comment

Landsat images from 199, 2002 and 2016 comparing glaciers draining into Storglomvatnet. Red arrows indicate 1999 terminus locations, purple dots the snowline.

Storglomvatnet has several glacier that terminated in the lake in 1999, Storglombreen Nord, Sorglombreen Sud and Tretten. This lake is the main reservoir, 3.5 billion cubic meters that feeds the 350 MW Svartisen Hydropower plant. The lake has an elevation of 585 m, while the power plant is at sea level. Paul and Andreassen,(2009) examined glacier area and found overall almost no areal extent change from 1968-1999 of Svartisen region glaciers, including the three examined here. Engelhardt et al (2013), note this was due to positive trends of winter balance between 1961 and 2000, which have been followed by a remarkable decrease in both summer and winter balances leading to an average annual balance of –0.86±0.15 m w.e.a^–1 between 2000 and 2010 .Since 1999 there have been changes. The Norwegian Glacier Inventory and the online digital atlas use this 1999 imagery and indicate glacier area for Storglombreen Sud at 15.9 km2, for Storglombreen Nord at 41.2 km2 and Tretten-nulltobreen at 5.9 km2.

In 1999 each of the glaciers reaches the lake shore at 585 m in four separate terminus fronts. The snowline in 1999 is at 1150 m. In early August 2002 the termini still reach the lake shore and the snowline is higher at 1250 m. In 2001, 2002 and 2003 mass balance measurements by the Norwegian Water Resources and Energy Directorate, indicate the snowline reached the top of the glacier at 1580 m. In 2016 the glacier termini no longer reach the lake shore and the snowline is again at 1150 m. It is evident in the Landsat image above that Storglombreen Sud and Tretten-nulltobreen no longer reach the lake shore, the southern most and northern most termini and arrows. The two termini of Storglombreen Nord no longer reach the lake, though this requires higher resolution Sentinel 2 images to illustrate. Retreat of Tretten-nulltobreen from 1999-2016 has been 200 m, of Storglombreen Sud 250 m and of Storglmbreen Nord 100-200 m. There was limited calving into the lake and the retreat from the lake will not significantly alter the retreat rate of the glacier. The high snowlines of recent years will lead to continued retreat. The retreat here is much less than on Engabreen which shares a divide with Storglombreen Nord, Flatisen or Blåmannsisen.

Map of the glaciers in the region from the Norwegian Glacier Inventory online map application, based on 1999 images.

Sentinel 2 image of the glaciers of Storglomvatnet from August 2016. Notice that none of the termini reach the lake shore.

Winsvold, Andreassen and Kienholz (2014)

Porcupine Glacier, BC 1.2km2 Calving Event Marks Rapid Retreat

On September 22, 2016May 2, 2024 By mspeltoIn Canada glacier retreat, glacier climate change7 Comments

Landsat images from Sept. 2015 and Sept. 2016. Red arrow is the 1988 terminus and the yellow arrow the 2016 terminus. I marks an icefall location and point A marks the large iceberg.

Porcupine Glacier is a 20 km long outlet glacier of an icefield in the Hoodoo Mountains of Northern British Columbia that terminates in an expanding proglacial lake. During 2016 the glacier had a 1.2 square kilometer iceberg break off, leading to a retreat of 1.7 km in one year. This is an unusually large iceberg to calve off in a proglacial lake, the largest I have ever seen in British Columbia or Alaska. NASA has generated better imagery to illustrate my observations. Bolch et al (2010) noted a reduction of 0.3% per year in glacier area in the Northern Coast Mountains of British Columbia from 1985 to 2005. Scheifer et al (2007) noted an annual thinning rate of 0.8 meters/year from 1985-1999. Here we examine the rapid retreat of Porcupine Glacier and the expansion of the lake it ends in from 1988-2016 using Landsat images from 1988, 1999, 2011, 2015 and 2016. Below is a Google Earth view of the glacier with arrows indicating the flow paths of the Porcupine Glacier. The second images is a map of the region from 1980 indicates a small marginal lake at the terminus.

Landsat images from 1988 and 2016 comparing terminus locations and snowline. Red arrow is the 1985 terminus and the yellow arrow the 2016 terminus. I marks an icefall location and point A marks the large iceberg. Purple dots indicate the snowline.

In 1988 a tongue of the glacier in the center of the lake reached to within 1.5 km of the far shore of the lake, red arrow. The yellow arrow indicates the 2016 terminus position. By 1999 there was only a narrow tongue reaching into the wider proglacial lake formed by the juncture of two tributaries. In 2011 this tongue had collapsed. In 2015 the glacier had retreated 3.1 km from the 1988 location. In the next 12 months Porcupine Glacier calved a 1.2 square kilometer iceberg and retreated 1.7 km, detailed view of iceberg below. The base of the icefall indicates the likely limit of this lake basin. At that point the retreat rate will decline.The number of icebergs in the lake at the terminus indicates the retreat is mainly due to calving icebergs. Glacier thinning of the glacier tongue has led to enhanced calving. The retreat of this glacier is similar to a number of other glaciers in the area Great Glacier, Chickamin Glacier, South Sawyer Glacier and Bromley Glacier. The retreat is driven by an increase in snowline/equilibrium line elevations which in 2016 is at 1700 m, similar to that on South Sawyer Glacier in 2016.

August 27, 2016 Sentinel 2 image of iceberg red dots calved from front of Porcupine Glacier.

Canadian Toporama map of Porcupine Glacier terminus area in 1980.

Google Earth view indicating flow of Porcupine glacier.

1999 Landsat image above and 2011 Landsat image below indicating expansion of the lake. Red arrows indicate the snowline. Purple, orange and yellow arrows indicate the same location in each image.

South Sawyer Glacier Retreat and Separation, Alaska

On September 20, 2016May 2, 2024 By mspeltoIn alaska glacier retreat, climate change glacier retreat, glacier climate change, Glacier Observations1 Comment

Comparison of South Sawyer Terminus position and unnamed glacier just to the south. Red arrows are the 1985 terminus and yellow arrows the 2016 position of each terminus.

South Sawyer Glacier is a 50 km long tidewater glacier terminating at the head of Tracy Arm fjord in Southeast Alaska. The winding fjord surrounded by steep mountains is fed by Sawyer and South Sawyer Glacier is home to stellar sea lions, humpback whales and harbor seals. This combination makes it attractive for cruise ships. Mike Greenfelder a Naturalist/Photography Instructor with Lindblad Expeditions suggested I examine this glacier, and he provided several images. I had a chance to observe the glacier in 1982 and 1984 and noted that the snowline of the glacier at 1125 meters by Pelto (1987), using Landsat images. We also identified the water depth at the glacier front was 180-200 m and the velocity of the calving front in the 1980’s was 1800 m/year (Pelto and Warren, 1990). Today the velocity had declined to less than half of this, which is expected given that water depth at the front in the most recent charts from 1999 indicate 1985 terminus position water depth is 110 m (Elliot et al, 2012). This is deep but not as deep as in the 1980’s, the greater the water depth, the greater the degree of buoyancy at the front and the higher the calving rate. The glacier retreated 3.5 km from 1899-1967 and then experienced little retreat from 1967 to 1985 (Molnia et al, 2008). Larsen et al (2007) observed a rapid thinning of the Stikine Icefield during the 1948-2000 period.The retreat has been driven by rising snowlines in the region that has driven the retreat of North Dawes, Baird, Dawes and Sawyer Glacier. Here we use Landsat images to indicate from 1985-2016 to identify terminus change and recent snowline elevation.

The terminus has retreated 2300 m from 1985 to 2016, with little retreat from 1985 to 1996. Of equal importance is the glacier now appears to be near the tidewater limit of Tracy Arm. In the gallery of terminus images below from Mike Greenfelder, the 2005 and 2012 images illustrate a sharp increase in slope at Point B and red arrows in 2015 just the red arrows, 300 m from the ice front. In 2016 the ice front is nearly to the base of this icefall. This represents a sharp rise in the bed of glacier causing an icefall. Whether the bed is entirely above sea level is not clear. Just south of the main terminus is a separate glacier that in 1985 was the combination of two tributaries. By 2016 the two glaciers have separated with a retreat of 4.5 km for the western arm and 3.8 km for the eastern arm.

In the gallery of snowline images it is evident that upglacier there are two tributaries that joined the main glacier in 1985, that no longer reach the glacier in 2016. This is indicative of the higher snowlines and thinning glacier. The gallery of snowlines indicate the last date during the melt season with clear imagery of the snowline. In 1985 the snowline was at 1250 m, in 1996 the snowline was at 1400 m, in 2013 1400 m, in 2014 1600 m, in 2015 at 1400 m and in 2016 at 1650 m. The images are close to the end of the melt season, but are a minimum elevation for the equilibrium line. The snowline is averaging 300 m higher than it did in the 1980’s. The retreat of South Sawyer Glacier and its iceberg production will slow as the water depth at the front declines in the near future. The retreat will continue due to the sharp rise in snowlines that has occurred which has led to significant thinning up to 1500 m noted by Larsen et al (2007). The retreat of neighboring non-calving glaciers emphasizes this point.

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Herbert Glacier Retreat, Alaska 1984-2016

On September 14, 2016May 2, 2024 By mspeltoIn alaska glacier retreat, climate change glacier retreat1 Comment

Comparison of Herbert Glacier terminus position in Landsat images from 1984 and 2016. Red arrow 1984 terminus, yellow arrow 2016 terminus and pink arrow a tributary that has separated.

Herbert Glacier drains the west side of the 4000 square kilometer Juneau Icefield in Southeast Alaska. It is the glacier just north of the more well known Mendenhall Glacier and just south of Eagle Glacier. It is also the first glacier I ever visited, July 3, 1981 during my first field season with the Juneau Icefield Research Program. Here we examine the changes from the August 17, 1984 Landsat 5 image to a Sept. 1, 2016 Landsat 8 image.

The glacier descended out of the mountains ending on the coastal plain in 1948. In 1984 we examined the terminus of this glacier, which was in the small proglacial lake at 150 m. Herbert Glacier has retreated 600 m since 1984. The width of the terminus has also declined. The pink arrow indicates a tributary that no longer feeds the main glacier. The retreat has not been enhanced by iceberg calving as is the case at Mendenhall Glacier. The overall retreat is also less than Eagle Glacier. In the Google Earth images below from 2005 and 2013 the retreat is 200 m, the terminus has fewer crevasses in 2013 suggesting a reduced velocity and faster retreat to come. The annual equilibrium line on the glacier has averaged 1150 m from 2003-2016. By contrast in August 1984 I skied to the top of the icefall and could see the snowline was at 1000 m. This leaves the glacier with an AAR of 0.45, too low to sustain equilibrium, retreat will continue. In 2015 and 2016 the snowline rose to over 1400 m by the end of the melt season, indicating two years of large mass loss, which will drive further retreat. The higher snow line elevation has been observed across the icefield Pelto et al (2013).

Transient snow line in Early Sept. of 2015 and 2016. The snow line is at the top of the icefalls, at 1400-1450 m.

2005 Google Earth Image, red line is 2005 margin, yellow line is 2013.

2005 Google Earth Image, red line is 1984 margin, yellow line is 2005.

Herbert Glacier Terminus in 2012

World Glacier Monitoring Service 30th Anniversary

On September 8, 2016May 2, 2024 By mspeltoIn climate change glacier retreat, glacier climate change, Glacier Observations

The numbers on the left y-axis depict quantities of glacial mass loss from the WGMS and sea level rise, and the suns across the horizon contain numbers that represent the global increase in temperature, coinciding with the timeline on the lower x-axis From Jill Pelto

The World Glacier Monitoring Service (WGMS) celebrated 30 years of achievement last week. I have had the privilege of being the United States representative to the WGMS and was an invited speaker for the Jubilee held in Zurich, Switzerland along with Matthias Huss, Wilfried Haeberli, Liss Marie Andreassen and Irene Kopelman. This post examines the important role that WGMS has and continues to serve under the leadership of Michael Zemp. The organization has been compiling, homogenizing and publishing data on glacier fluctuations and mass balance primarily from 1986-2013. WGMS remains the leading organization for the collection, storage and dissemination of information on the fluctuations of alpine glaciers. The resulting standardized collection of alpine glacier data that is archived by WGMS, is also leading to analysis efforts that otherwise would be hampered by limited data and lack of homogeneity to the data. Glaciers are recognized as one of the best climate indicators. Mass balance data is the best parameter to measure on glaciers for identifying climate change, because of its annual resolution. The core of the WGMS data set has been frontal variations, which indicate longer response to climate as well as dynamic changes. The key data set today provided by WGMS are the reference glaciers.

This set of glaciers has a 30-year continuous record of annual mass balance measured in the field, and each glacier also has geodetic verification. This mass balance data set is featured on the Global Climate Dashboard at NOAA. I report the mass balance of two reference glaciers Lemon Creek Glacier in Alaska and Columbia Glacier in Washington. Today the field based work is being increasingly supplemented and supplanted by remote sensing methods. This data sets indicates a period of sustained mass balance loss, and glacier retreat that Zemp et al (2015) using WGMS data noted as historically unprecedented. The most recent compilation publication is the Global Glacier Change Bulletin.

This data set is of particular value during this period of climate change and is already chronicling the disapperance of a number of glaciers in the data set. Glacier loss is not a process that has been well documented. The WGMS data set can be enriched by more data from expanding monitoring, reporting data from archives and simply adding the submission of data as a step in the research process for those monitoring alpine glaciers. The video of my presentation looking at 33 consecutive years of field work and sharing this data after compilation with the WGMS is below. The slides below are from the Jubilee presentations.

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West Hongu Glacier Retreat-Ablation Extending into January, Nepal

On September 6, 2016May 2, 2024 By mspeltoIn Himalaya glacier retreat

Landsat comparison of West Hongu Glacier snowline, purple dots from October 2015 to January 2016. The red arrow indicates the 1993 active terminus location and the yellow arrow the 2015 active terminus location.

West Hongu Glacier is a small glacier in the Dudh Khosi Basin of Nepal. The glacier drains the east side of Ama Dablam Peak. Shea et al (2015) noted that glaciers in the Dudh Khosi Basin of Nepal lost 16% of total volume and 20% of area from 1961-2007. Shea et al (2015), in an ICIMOD project, modeled future changes in glaciers with various climate scenarios, finding a minimum projected volume change by 2050 of −26 % and maximum of −70 %. This glacier is a short distance from Mera Glacier where mass balance is measured. Both are summer accumulation type glaciers with 80% of annual precipitation occurring during the summer monsoon season. Salerno et al (2015) found that the main and most significant increase in temperature is concentrated outside of the monsoon period, leading to more ablation favoured during winter and spring months, and year around close to the glacier terminus. The lake at the end of the glacier is unnamed and not listed as one of 20 lakes recorded as potentially unstable and warranting further investigation in Nepal (Ives et al., 2010). ICIMOD has continued to inventory and assess the hazards from glacier lakes and their capacity to induce outburst floods. ICIMOD notes the area of the lake is 0.366 square kilometers.

Here we examine the snowline from fall into winter in 2015/16. Above is the comparison indicating the rise of the snowline from October into January. This has been a common occurrence in recent years, indicating that ablation though limited, continues in the post-monsoon into the mid-winter period. The snowline rises from 5550-5600 m in October to 5650-5700 m in January. Besides ongoing ablation into January, the high snowline illustrates the lack of significant accumulation at any elevation on the glacier in the post Monsoon period extending into January. The snowline remained high on Jan.20, 2016, but the image has considerable cloud cover. This tendency has been noted at Nup La-West Rongbuk Glacier, on the Nepal-China border, Chutanjima Glacier, China and Lhonak Glacier, Sikkim.

Below the active ice terminus change from 1993-2013 is noted. The active ice ended on the shore of the lake in 1993, red arrow. By 2013 the active ice has retreated 500 m from the lake, yellow arrow. There is still debris covered stagnant ice in this zone. The inactive ice is dissected by significant stream channels that cannot develop in an area of active ice. Some of the stream channels have cut to the base of the glacier.

Comparison of active terminus location from 1993-2013 in Landsat images. The red arrow indicates the 1993 active terminus location and the yellow arrow the 2015 active terminus location.

Terminus of West Hongu Glacier inn 2013. Yellow arrows indicate the stream channels cutting through the debris covered inactive ice.Map below indicates glacier ending in the lake.

Moulins: Clarifying Impacts on Glacier Velocity

On September 1, 2016September 2, 2016 By mspeltoIn glacier climate change, Glacier Observations, Greenland glacier retreat

In the last week I have read three separate articles referring to glacier moulins as lubricating the bed of a glacier resulting in overall velocity increase, for example EOS (Aug. 2016), this is not generally accurate. Having spent considerable time observing moulins and reviewing some excellent studies that indicate their impact, it is worth noting again a more complete picture of the role moulins play. This is a role that warrants considerable further examination. In 2008 and 2011 I wrote a piece indicating why this a generalization that is only sometimes accurate. The key to increasing glacier velocity is high basal water pressure, not simply lots of meltwater. Think of your car, if you have low oil pressure that is an issue for efficient running. If you have high oil pressure that is ideal. If you have high oil pressure and you add more oil that does not further lubricate the engine. Delivering more water to the base of a glacier that already has lots of meltwater drainage will not typically lead to a significant acceleration. A number of studies since 2008 have better illustrated this principle as it applies to ice sheets.

Ahlstrøm et al (2013) examined 17 Greenland glaciers and noted a pattern, “Common to all the observed glacier velocity records is a pronounced seasonal variation, with an early melt season maximum generally followed by a rapid mid-melt season deceleration”. This indicates the Greenland glaciers are more like a typical alpine glacier and are susceptible to the forces that tend to cause alpine glaciers to experience peak flow during spring and early summer. Those forces are the delivery of meltwater to the base of the glacier, when a basal conduit system is poorly developed. This leads to high basal water pressure, which enhances sliding. As the conduit system develops/evolves the basal water pressure declines as does basal sliding, even with more meltwater runoff.

This is what has been reported to be the case by Sundal et al (2011) in Greenland. They found a similar early season velocity in all years, with a reduced velocity late in summer during the warmest years. This suggested that a more efficient melt drainage system had developed, reducing basal water pressure for a longer period of time. The meltwater lubrication mechanism is real, but as observed is limited both in time and area impacted. It is likely that, as on alpine glaciers, the seasonal speedup is offset by a greater slowdown late in the melt season. Most observed acceleration due to high meltwater input has been on the order of several weeks, leading to a 10-20% flow increase for that period.

Moon et al (2014) examined 55 Greenland glaciers and found three distinct seasonal velocity patterns. Type 1 behavior is characterized by speedup between late spring and early summer with speed remaining high until late winter or early spring, with the principal sensitivity being to terminus conditions and position. Type 2 behavior has stable velocity from late summer through spring, with a strong early summer speedup as runoff increases and midsummer slowing, as the glacier develops an efficient drainage system. Type 3 behavior has a mid-summer slowdown leading to a pronounced late summer minimum during the period of maximum runoff. Velocity than rebounds over the winter. The common behavior is then a slowdown during periods of peak runoff and moulin drainage.

Anderson et al (2011) noted that changes in velocity due to a 45% change in meltwater input were small 4-5% on Helheim Glacier.

Clason et al (2015) modelled development of moulins and their ability to deliver the water to the bed of Leverett Glacier. This study illustrates the level of details that is being examined to better model meltwater routing, which will inform flow models as noted by EOS (2015).

Moulins increase meltwater flow to a glacier bed. In areas where significant surface melt occurs, this tends to lead to an early melt season increase in basal water pressure and then velocity. This is typically followed by a mid/late melt season deceleration with continued meltwater drainage through moulins. The lubrication is hence, restricted in time, and if followed by a deceleration, does not necessarily lead to an increase in the overall glacier velocity. Certainly in some cases moulins will increase overall velocity and in others not.

Lednikovoye Glaciers, Novaya Zemlya 1999-2016 retreat

On August 29, 2016May 2, 2024 By mspeltoIn glacier climate change, Novaya Zemlya glacier retreat, russia glacier retreat

Comparison of glaciers terminating in Lednikovoye Lake in central Svalbard in 2000 and 2016. Red arrow is the 2000 terminus location and yellow arrows the 2016 terminus location.

Lednikovoye Lake in central Novaya Zemlya has four glaciers terminating in it. Here we examine the two unnamed glaciers that discharge into the northwest portion of the lake. The glaciers are retreating like all tidewater glaciers in northern Novaya Zemlya, though they are not specifically tidewater (LEGOS, 2006). LEGOS (2006) identified a 2.7 square kilometer reduction in area of the two glaciers from 1990-2000. Carr et al (2014) identified an average retreat rate of 52 meters/year for tidewater glaciers on Novaya Zemlya from 1992 to 2010 and 5 meters/year for land terminating glaciers.Here we use Landsat images to examine changes from 1999 to 2016.

In 1999 and 2000 the western Lednikovoye Glacier ended on an island, the eastern Lednikovoye Glacier extended past the exit of a glacier filled valley entering from the east. By 2016 the western terminus had retreated 800 meters from the newly developed island. The eastern terminus had retreated a similar amount now ending near the center of the valley entering on the east. The glacier in that eastern valley has retreated 600 m from 1999 to 2016. The snowline in 2000 and 2016 is at ~500 m, with a significant remaining accumulation zone. There is limited upglacier thinning suggesting that retreat will not become rapid. The reduced rate of retreat of the Lednikovoye Glacier’s versus tidewater glacier of Novaya Zemlya suggests the importance of both sea ice reduction and sea surface temperature increase to the retreat rate of the latter such as Krayniy Glacier, Tasija Glacier and Chernysheva Glacier.