Yajun Peak Glacier Retreat, Afghanistan

On November 15, 2012November 16, 2012 By mspeltoIn Glacier Observations

Glaciers of Afghanistan have received little detailed attention for obvious reasons, only satellite image analysis of selected areas has been completed Haritashiya et al (2009) and Shroder and Bishop (2010), both studies noting a significant retreat and downwasting. In this post glaciers in the remote area around Yajun Peak in the Hindu Kush 150 km northeast of Bagram Airbase and 75 km west of the Pakistan Border are examined. Landsat imagery from 1998 (1st image below), 2010 (2nd image below) and 2012 (3rd image below) are used in combination with 2008 Google Earth imager (Last image below). Changes in three glaciers on Yajun Peak (6024 m) are highlighted. The yellow arrows indicate the expansion of bare rock amid a glacier draining south from Yajun Peak. The expansion of the bare rock area from the terminus area in 1998 to 2012 is evident as is the expanded area of the ridge in the upper glacier noted by the yellow arrow in each image. The magenta arrows indicate the terminus of a glacier draining west from Yajun Peak that in 1998 did not have a lake at the terminus. In the 2008, 2010 and 2012 imagery a small lake has developed as the glacier has thinned and retreated. The third glacier flows northwest and terminates in 1998 at a green line that is a one kilometer long line between two specific topographic points in each image. The glacier has retreated from the green line by 2008 and the retreat is 125 meters by 2012. In the 2008 Google Earth image a purple arrow points out the upper basin of a fourth glacier that is no longer ice or even snow filled. This along with the expansion of the bedrock ridge near the top of the glacier with yellow arrows indicates that even the accumulation zone of these glaciers are not persistently snow covered. Glaciers that lack a persistent snowcover cannot survive (Pelto, 2010). To see the details just click on each image and an expanded version will appear.
In previous posts on glaciers in the region the Emend Watershed and Zemestan Glacier the retreat is similar.

Porisjokull Retreat, Iceland

On November 11, 2012 By mspeltoIn Glacier Observations

Porisjokull (Thorisjokull) is a small 25 square kilometer ice cap southwest of Langjokull. The top elevation of the icecap is just 1350 m. This ice caps outlet glaciers have been in retreat as have almost all Iceland glaciers in the last decade (Helgi Björnsson and Finnur Pálsson, 2008). Examination of Landsat images from 2000, 2002, 2011 and 2012, shown in that order below, are used to identify changes in Porisjokull. The primary changes in the periphery are retreat of two lobes on the east side of the icecap at the yellow and red arrow and loss of ice at glacier connections green arrow and purple arrow. The comparison of the 2000 and 2011 images in particular illustrate the complete loss of the lobes at the yellow and red arrow. Between outlets of the icecap areas of glacier area have diminished significantly at the green and purple arrow. The lobe at the yellow arrow has been lost, this represents a retreat of 500 m. At the red arrow the lobe has also been lost, a retreat of 400 m. In the Google Earth images below the lobes still exist. At the green arrow the glaciated area declined from 1.2 square kilometers to 0.5 square kilometers. At the Purple arrow the margin of this intermediate lob has retreated 300 m. The icecap changes has mirrored that of nearby Langjokull, Gudmundsson et al (2008) identified thinning across the accumulation zone of Langjokull from 2000-2007. This led to retreat of the largest outlets of Langjokull.
Bjornsson and Gislason (2010) have examined the climate change that is driving the response of the glaciers.

Lapperent Outlet Thinning and Retreat, Kerguelen Island

On November 8, 2012November 6, 2014 By mspeltoIn Glacier Observations1 Comment

Kerguelen Island sits alone at the edge of the furious fifties in the southern Indian Ocean. The island features numerous glaciers, the largest being the Cook Ice Cap at 400 square kilometers. A comparison of aerial images from 1963 and 2001 by Berthier et al (2009) indicated the ice cap had lost 21 % of its area in the 38 year period. In this paper they focused particular attention on the Ampere Glacier, pink arrow in first image, draining the southeast side of the ice cap, that had retreated 2800 meters from 1963 to 2006. Berthier et al (2009) had a second focus on the Lapparent Nunatak due north of the main terminus and close to the east terminus, referred to hear as the Lapparent Outlet. A nunatak is a ridge or mountain surrounded by a glacier, really an island in a sea of ice. The nunatak expanded from 1963-2001, in the second image below from Berthier et al (2009), but it was still surrounded by ice. . In this post we examine changes at the terminus and at several points upglacier in 2001 and 2011 Landsat imagery that indicate widespread thinning and deglaciation. In each image the letters are in the same location as are the colored arrows. The green arrow indicates the 2001 terminus of the outlet and the burgundy arrow the 2011 terminus, indicating a 2 km retreat in a single decade for the southern calving terminus and for the northern terminus above point D 2200 meters of retreat. In 2001 the region around letter D is a filled by the northern arm encircling the Lapparent Nunatak, by 2011 D is in a deglaciated valley. B marks the southern end of the 2011 terminus. F in 2011 marks a location where the Lapparent Outlet spills over a ridge into another valley, by 2011 the overflow has narrowed from 1100 meters to just 500 meters in ten years. The result is less ice flow into the secondary basin, including down a bedrock step to point E. Point E in 2001 is in the midst of the lower reach of the glacier. By 2011 there is no ice near point E as the glacier no longer descends to this lower step. Point A in a nunatak 4 km inland from the Ampere and Lapperent Outlet terminus, this nuntak has expanded from a long axis of 1100 meters to 1500 meters. Berthier et al (2009) had noted thinning around the Lapprent Nunatak of 150 to 250 m. This continued thinning since 2001 is leading to further expansion of the nunatak at A and to reduced ice spillover at point F. This island and glacier is experiencing the same climatic warming that is causing retreat of other glaciers in this circum-Antarctic latitude belt, Stephenson Glacier on Heard Island, Neumayer Glacieror Ross Hindle Glacier on South Georgia and on the north side of Cook Ice Cap, Kerguelen Ice Cap.

Chuecon Glacier Retreat, Peru

On November 4, 2012February 14, 2013 By mspeltoIn Glacier Observations3 Comments

In the Cordillera Centrale of Peru a series of glaciers extends north from Pariacaca. Pariacaca is the pre-Incan god of water, appropriate name in this dry region, that is draped with glaciers and has numerous alpine lakes. In fact with glacier retreat the number of lakes is increasing. Here we examine the Chuecon Glacier which descends from Nevado Suerococha, and ends in a new lake before draining into the Rio Carhuapampa. This area has has escaped attention on its recent retreat. The retreat of the Chuecon Glacier over the last decade is documented with a comparison of Landsat and Google Earth imagery from 1997, 1998, 2005,2010 and 2012. The Chuecon Glacier terminus is indicated with a pink arrow in the Landsat images. The green arrow is the Manon Glacier. In 1997 and 1998 the lake at the terminus has not yet begun to form, by 2005 a small lake has developed at the north corner of the terminus. By 2010 the lake is 450 meters from north to south and 150 to 200 m east to west. The retreat from 1997 to 2010 is 200 meters. A closeup view of the glacier indicates that even in the accumulation zone bedrock is being exposed amidst the icefall and the accumulation zone margin in retreating, pink arrows in both images. The terminus currently is calving into the lake some, an upwelling area where the subglacial glacier runoff stream enters the lake is evident, yellow arrow. The terminus area also has ablation depressions forming an indication of stagnation, principally on the southern arm of the glacier, pink arrows. The purple arrow on the bottom image indicates the terminus in 1997. The combination of limited accumulation area and ablation depressions indicative of stagnation indicate a glacier that is not only retreating, but will not survive (Pelto, 2010). The ongoing field work at Quelcaya Ice Cap, led by Doug Hardy at UMASS, provides a detailed view of what is happening to glaciers in the region. Bryan Mark at Ohio State University has also been observing detailed changes around Mount Pucaranra, Peru.

Glacier Post Index through October, 2012

On November 1, 2012November 24, 2012 By mspeltoIn Glacier Observations1 Comment

Below is a list of the individual glacier posts examining our warming climates impact on each glacier. This represents the first 3.4 years of posts, 244 total posts, 223 different glaciers. I have worked directly on 45. The others are prompted by fine research that I had come across, cited in each post or inquiries from readers and other scientists. I then look at additional often more recent imagery to expand on that research. The imagery comes either from MODIS, Landsat, Geoeye or Google Earth. There is a consistent signal from the glaciers, mass balance loss, thinning and retreat. In many cases this leads to new lake formation or lake expansion for alpine glaciers. I will continue to record these changes here with a new post twice a week and in the field.

New Zealand
Tasman Glacier
Murchison Glacier
Donne Glacier
Mueller Glacier, NZ
Gunn Glacier, NZ

Africa
Rwenzori Glaciers
Tyndall Glacier, Kenya

Himalaya
Ngozumpa Glacier, Nepal
West Barun Glacier, Nepal
Samudra Tupa, India
Malana Glacier, India
Longbasba Glacier, Tibet
Zemu Glacier, Sikkim
North Lhonak Glacier, Sikkim
Theri Kang Glacier, Bhutan
Zemestan Glacier, Afghanistan
Emend River Headwaters, Afghanistan
Godur Glaicer, Pakistan
Tirich Mir, Pakistan
Khumbu Glacier, Nepal
Imja Glacier, Nepal
Gangotri Glacier, India
Milam Glacier, India
Satopanth Glacier, India
Kali Gandaki Headwaters, Nepal
Menlung Glacier, Tibet
Boshula Glaciers, Tibet
Urumquihe Glacier, Tibet
Sara Umaga Glacier, India
Dzhungharia Alatau, Kazakhstan
Petrov Glacier,Kyrgyzstan
Hailuogou Glacier, China
Reqiang Glacier Retreat, Nepal
Lumding Glacier, Tibet
Himalaya Glacier Index

Europe
Taconnaz GLacier, France
Mer de Glace, France
Dargentiere Glacier, France
Grand Motte and Pramort Glacier Tignes Ski area, France
Saint Sorlin, France
Sommelier Glacier
Obeeraar Glacier, Austria
Ochsentaler Glacier, Austria
Pitzal Glacier, Austria
Dosde Glacier, Italy
Maladeta Glacier, Spain
Presena Glacier, Italy
Lobbia Glacier, Italy
Sabbione Glacier Retreat
Triftgletscher, Switzerland
Gietro Glacier, Switzerland
Rotmoosferner, Austria
Stubai Glacier, Austria
Hallstatter Glacier, Austria
Ried Glacier, Switzerland
Cavagnoli Glacier, Switzerland
Chuebodengletscher and Ghiacciaio-del-Pizzo-Rotondo
Forni Glacier, Italy
Careser Glacier, Italy
Peridido Glacier, Spain
Engabreen, Norway
Midtdalsbreen, Norway
Tunsbergdalsbreen, Norway
TungnaarJokull, Iceland
Langjökull, Iceland
Gigjokull, Iceland
Skeidararjokull, Iceland
Kotlujokull, Iceland
Lednik Fytnargin, Russia
Rembesdalsskaka, Norway
Irik Glacier, Mount Elbrus, Russia

Greenland and European Arctic
Mittivakkat Glacier
Ryder Glacier
Humboldt Glacier
Petermann Glacier
Kuussuup Sermia
Thrym Glacier Retreat
Tiningnilik Glacier Lake
Jakobshavn Isbrae
Zachariae Isstrom
Umiamako Glacier
Alison Gletscher
Kong Oscar, Glacier
De Reste Bugt
Upernavik Glacier
Apuserajik Glacier
Epiq Sermia
Sarqardliup Seremia
Steensby Glacier
Sortebrae Glacier, Greenland
Severnaya Zemlya, Russian Arctic
Hansbreen, Svalbard
Nannbreen, Svalbard
Hornbreen and Hambergbreen, Svalbard
Olsokbreen, Svalbard
Albrechtbreen, Svalbard
Roze and Sredniy Glacier, Novaya Zemyla
Nizkiy and Glazova Glacier, Novaya Zemyla

South America
Colonia Glacier, Chile
Artesonraju Glacier, Peru
Nef Glacier, Chile
Tyndall Glacier, Chile
Alemania Glacier, Chile
Zongo Glacier, Bolivia
Sierra Nevade del Cocuy Glaciers, Colombia
Ritacuba Blanco Glacier, Colombia
Llaca Glacier, Peru
Joerg Montt Glacier, Chile
Nororeste Glacier, Chile
Arhuey Glacier, Peru
Seco Glacier, Argentina
Onelli Glacier, Argentina
Quelccaya Ice Cap, Peru
Manon Glacier, Peru
Glacier Gualas, Chile

Antarctica and Circum Antarctic Islands
Pine Island Glacier
Fleming Glacier
Hariot Glacier
Smith Glacier, Antarctica
Thwaites Glacier, Antarctica
Amsler Island
Stephenson Glacier, Heard Island
Neumayer, South Georgia
Ampere, Kerguelen
Cook Ice Cap, Kerguelen Island
Nordenskjold Coast, Antarctic Peninsula
Prospect Glacier, Antarctic Peninsula
Ross Hindle Glacier, South Georgia
Vega Island Ice Cap
Rohss Bay, James Ross Island, Antarctica

North Cascade Glacier Climate Project Reports

Forecasting Glacier Survival
North Cascade Glacier Mass Balance 2010
Columbia Glacier Annual Time Lapse
North Cascade Glacier Climate Project 2009 field season
28th Field Season Schedule of the North Cascade Glacier Climate Project
North Cascade Glacier Climate Project 2011 Field Season
BAMS 2010 alpine glaciers
BAMS 2011 Alpine Glaciers
2011 Glacier mass balance North Cascades and Juneau Icefield
Taku Glacier TSL Paper
Glacier Ground Truth 2012 North Cascade Field Season
North Cascade Glacier Climate Project 2012 Field Season

Guyot Glacier Retreat, Icy Bay Alaska

On October 29, 2012 By mspeltoIn Glacier Observations

Guyot Glacier a century ago was joined with the Tyndall and Yahtse Glacier with an ice front that reached just beyond the entrance of Icy Bay. Today Guyot Glacier has retreated more than 50 km. This post examine satellite imagery from 1984-2010 to illustrate ongoing thinning and retreat of the Guyot Glacier. Guyot Glacier has retreated more than 50 km since 1904 (Molnia, 2007). As retreat began the glacier had a calving front that was over 10 km long. The glacier was also calving into deep water. This led to a rapid retreat up to 1938 (USGS). In the sequence of images below from the USGS, this is evident. By 1969 the glacier had separated into three sections, middle image in sequence and by 1986 the Guyot Glacier had retreated a considerable distance up the newly exposed fjord. The pink arrow points to the Kashteen Peninsula that will emerge, and the orange arrow to the 1984 terminus position of Guyot Glacier. Barclay et al (2009) have illustrated the dynamic nature of this glacier that has had three large (40 Km+) advances and retreats in the last 4000 years. The Landsat image sequence is from 1984, 1995, 2000 and 2010. In each image the pink arrow indicates an area on the Kashteen Peninsula that was still covered by the glacier until 1980. In 1984 on Kashteen there are two ice masses with an area of 1.3 square kilometers, by 1995 one small ice mass of 0.3 square kilometers, by 2000 the stranded ice masses are gone. By 2010 the area is showing considerable vegetation development. This indicates a relatively short ecesis rate, rate of vegetation returning after deglaciation. The orange arrow indicates the 1984 terminus of Guyot Glacier. The green arrow is the 2010 terminus position of Guyot Glacier, the main terminus retreated 3.8 km during the 26 year period. The yellow arrow indicates the expansion of a bare bedrock region on the south side of the main Guyot Glacier terminus that now extends 2 kilometers from the margin. The red arrow is a separate terminus of an unnamed glacier that ended in Tsaa Fjord up to 2000, and is no longer tidewater, having retreated 400 meters from tidewater and 600 meters since 1984. Tidewater glaciers have two means to lose mass calving and melting. The former can be insensitive to climate and is more dependent on water depth and calving width (Brown et al, 1982). Pelto (1987) and Viens (1995) produced models showing that climate acts as a first-order control on the advance/retreat cycle of calving glaciers during most of the advance retreat cycle, but there are climate insensitive periods of the tidewater glacier cycle too (Meier and Post, 1987). In the case of Guyot Glacier today the peripheral areas at the yellow and red arrows indicate considerable thinning in areas that are no longer calving and indicate that mass balance losses are still occurring without calving, hence, climate driven. For the main Guyot Glacier the current ratio of the accumulation area to the melt area is quite high. This is the accumulation area ratio, and it is high enough to be in equilibrium if calving is reduced. The Brady Glacier is at the other end of the cycle, just beginning a large retreat due to extensive thinning from recent reduced mass balance. Yakutat and Valdez Glacier are two nearby glaciers that have also experienced large calving retreats, though both still have large ablation (melt) areas.

Manon Glacier Retreat Lake Formation, Peru

On October 28, 2012February 14, 2013 By mspeltoIn Glacier Observations1 Comment

In the Cordillera Centrale of Peru a series of glaciers extends north from Pariacaca. Pariacaca is the pre-Incan god of water, appropriate name in this dry region, that is draped with glaciers and has numerous alpine lakes. In fact with glacier retreat the number of lakes is increasing. Here we examine the Manon Glacier which descends from Nevado Suerococha and drains into the Rio Carhuapampa. This area has received little attention when it comes to glacier study. A glacier lake outburst flood from the Suerococha Basin in 1941 is the only noted event. The retreat of the Manon Glacier over the last decade is documented with a comparison of Landsat and Google Earth imagery from 1997, 1998, 2005,2010 and 2012. The retreat of these glaciers matches the more closely observed Cordillera Blanca and Quelcaya Ice Cap region (Mark., 2008 and Vuille et al, 2008). The Manon Glacier terminus is indicated with a green arrow in the Landsat images. The pink arrow is the Chuecon Glacier which will be the focus of a later post. In 1997 the lake at the terminus has not yet begun to form, by 2005 the lake has nearly reached its full size, and the glacier is still terminating in it. By 2010 and 2012 the glacier no longer reaches even the edge of the new lake. The retreat from 1997 to 2010 is 550 meters, the lake is 500 meters long. The 2010 Google Earth image indicates no snow snow on the southern half of the glacier, even at its highest altitude of 5200 m, the larger section coming off the main peak has a snowline at 5100 meters. A closeup of the terminus indicates that the southern portion of the glacier also has a number of features indicative of stagnation, pink arrows. Thesse are depressions that have higher debris concentration and are wind scoured, both enhancing melting. If the debris cover was a thick blanket it could retard melting. This type of ablation hollow is also seen at the top of the southern section of the glacier, indicating this part no longer has an accumulation zone and will melt away.

Tirich Mir Region Glacier Retreat, Pakistan

On October 25, 2012May 9, 2013 By mspeltoIn Glacier Observations

Tirich Mir is the highest mountain in the Hindu Kush and is in the northwestern corner of Pakistan. Here we examine Google Earth and Landsat imagery from two glaciers off the southwest ridge of Tirich Mir. The two glaciers are unnamed and are in the Dir Gol Valley, that starts in Akari, Pakistan and drains the southwest side of Tirich Mir, red arrows. A 2000 Landsat image (top image) indicates both glaciers ending in small lakes. The arrows in all images are purple for the lack of snowcover even in the glacier accumulation zone, red for the 2000 terminus, yellow for the Google Earth terminus and green for the 2011 terminus. By 2008 the Google Earth imagery indicates that the eastern of the two has retreated 400 meters leading to a more than doubling of the lake size. For the western glacier, the glacier still maintains has just retreated from the lake margin. The lake is slightly larger than in 2000. There is no snowpack on either glacier in the Google Earth imagery or in the 2000 image even at 5000 meters. This indicates glaciers without persistent accumulation zones, which means they cannot survive (Pelto, 2010). By 2010 and 2011, last two images. The eastern glacier has retreated an additional 100 meters and the lake is still expanding. The western glacier is no longer in contact with the lake, the terminus is now 150 m from the lake. The retreat from 2000-2011 of the eastern glacier has been 500 meters and 200 meters for the western glacier. The rretreat is similar to that of Godur Glacier in the Swat Valley. After 2000 76% of the glaciers in the region have been retretaing (Sarikaya et al, 2011). Around Tirich Mir glacier retreat had been relatively low up to this point. Most of the glacier in this region of the Hindu Kush

Glacier Noroeste Retreat, Gran Campo Nevado, Chile

On October 20, 2012October 21, 2012 By mspeltoIn Glacier Observations

The Gran Campo Nevado (GCN) is the smallest of the four primary Patagonian Icefields. It is on the Península Muñoz Gamero 200 km to the south of the Southern Patagonia Icefield. The major outlet of this icefield is the Noroeste Glacier. In a recent paper examining the changes in Patagonia glacier from 1870-2010 (Davies and Glasser, 2012), observed that the Gran Campo Nevado icefield lost of its area from 1870-2010, and 14% of its area from 1986-2011. Davies and Glasser (2012), Aberystwyth University, also documented that 21 of the 31 glaciers of the icefield experienced their most rapid retreat of the last 140 years during the 1986-2010 period. Nororeste Glacier has been a focus in two papers Scheider et al,(2007) and Moller and Schenider (2010). These papers document a retreat of 1100 m from 1986-2002 first image below, they further identify that the glacier area has declined by 4 square kilometer from 1986-2007, and in 2007 was just under 50 square kilometers. Moller and Schenider (2010) develop an areal extent model for the glacier that indicates the glacier will lose a further 15 square kilometers by 2100. The second image is showing the areal extent change from Davies and Glasser (2012), with the red arrow indicating Nororeste Glacier and the yellow the deglaciated area since 1870. Here we examine Landsat imagery from 1999, 2007 and 2012. The 1986 terminus is noted by the orange line, the 2002 margin is a yellow line, the 2007 terminus a purple line and the the 2012 terminus indicated by pink arrows. The retreat from 1986-1999 was 600 meters, from 1999-2007 1050 meters and 2007-2012 250 meters. The overall retreat of 1900 meters from 1986-2012, is 73 meters/year and from 1999-2012 the 1300 meter retreat is 100 meters/year. One other noteworthy change is the thinning and retreat at the northern margin that has led to the drainage of an. ice dammed lake that is present in 1999, red arrow and gone in 2012. The lake had drained by 2007 but that is not evident in the deep shadows of the Landsat image. This glaciers retreat fits the regional patter of glaciers to the north, Joerg Montt Glacier, Colonia Glacier, Glacier Gualas and Alemania Glacier to the south. This also fits the overall pattern of area loss that increased after 1986 and has remained high (Davies and Glasser, 2012) and the ongoing detailed studies of the Chilean Laboratorio de Glaciologia

The retreat is partly due to calving of icebergs into the lake the glacier terminates in, as evident by the icebergs visible in each satellite image above and in the Google Earth image below of icebergs in the lake in 2004.

Bastion Glacier Retreat, Wind River Range, Wyoming

On October 18, 2012October 18, 2012 By mspeltoIn Glacier Observations

Between Bastion and Rampart Peak just north of Gannett Peak in the Wind River Range of Wyoming is a smaller unnamed glacier. It is distinct from the Gannett Glacier and here we refer to it as the Bastion GlacierExamination of this glacier from the 1966 based USGS map, 1994 USGS photography and 2006 and 2009 Google Earth Imagery and a 2012 climbing photograph. The glacier area is from the 1966 map is outlined in purple, in 1994 is green and 2006 in brown. In 1966 the Bastion Glacier was joined at its terminus with a glacier to its north below the east ridge leading to the summit, blue arrow. By 1994 the glaciers are separated and by 2006 the division has expanded. At the red arrows two areas of bedrock are expanding into the midst of the glacier, and by 2012 the lower outcrop is particularly important. The 2012 photograph is from Sarah T. The retreat during this period is 120 meters from 1966-2009, with most of the retreat, 80 meters occurring since 1994. More importantly for this glacier is the expansion of bedrock outcrops in the midst of the glacier, red arrows low on the glacier and purple arrows high on the glacier. Orange arrows indicate the expansion of bare area as the glacier north of the ridge has lost dramatic area. Below are the images in order from 1966, 1994, 2006, 2009 and 2012. The ongoing and thinning of this glacier of this glacier is following the same path as Minor Glacier, Knife Point and Sourdough Glacier, but slower. The image from 2012 is from late July. The melt season in 2012 continued up to October, 3rd, as identified from the temperature records at SNOTEL sites in the area. By the end of the melt season a further 3 meters of snow and ice was lost from Bastion Glacier. The expansion of bedrock outcrops in the upper portion of the glacier indicates lack of a persistent and consistent accumulation zone, a symptom of a glacier that cannot survive (Pelto, 2012).

Apuserajik Glacier Retreat, southeast Greenland

On October 12, 2012June 28, 2013 By mspeltoIn Glacier Observations

Anders Anker Bjørk at the Centre for GeoGenetics, Natural History Museum of Denmark, University of Copenhagen alerted me to the retreat of the Apuserajik Glacier (just south of Helheim Glacier), which is not a unique name for a Greenland glacier. Here we examined satellite imagery from 1986, 2000, 2003, 2008 and 2011 to document the retreat, development of a new island and the drainage of a former ice dammed lake. Bjørk et al.(2012)identify the terminus change of 132 glaciers in southeast Greenland over the last 80 years. They observe that the observational period can be divided into three periods. Two recessional events 1933-1943 at the onset of their observations and 2000-2010. There was also a period of widespread advance from 1943 to 1972. In their supplement Table 7 identify the retreat of SEGL017-Apuserajik Glacier from 1933 to 2010. There was a 1.5 km retreat from 1933-1972, a 0.9 km retreat from 1972 to 1985 and a 3.7 km retreat from 1985-2010. The rate from 1933-1985 was 50 m/year, and from 1985-2010 was 140 m/year. The first image is from 2011 and the red terminus line is from 1986, the orange line from 2000, the green line from 2008 and the magenta line from 2011. Below the first image is the sequence in order of 1986, 2000, 2003, 2008 and 2011, the red arrow in each indicates the 1986 terminus and the magenta arrow the new island at the 2011 terminus. The lake that is at the 2008 terminus is quite substantial in 1986 and 2000, by 2003 it has drained considerably and is near its current size, having separated into several pieces. The terminus has retreated 4.2 km from 1986 to 2011, a rate of about 160 m/year. The Apuserajik Glacier was not observed to readvance by Bjørk et al (2012). The retreat here and the change in the characteristics of the lake in a former side valley, is similar to the retreat and opening of a new fjord at Thyrm Glacier. The Helheim Glacier just to the north is a much larger and faster moving glacier that has garnered considerable attention and has retreated 4.8 km from 1985-2010 (Joughin et al 2008; Howat et al, 2005; Andresen et al, 2011))The last image is a closeup of the new islands and the narrower lake entrance. With the new islands being noted by orange and magenta arrows. The yellow arrow indicates a valley that was in 1986 filled by glacier ice and is increasingly bare rock, indicating the upglacier thinning.

Thwaites Glacier Tongue Major Calving Event, Antarctica

On October 8, 2012June 14, 2013 By mspeltoIn Glacier Observations6 Comments

During the Austral winter between April and September, 2012 the Thwaites Glacier a large outlet glacier of the West Antarctic ice Sheet experienced a major calving event, as was pointed out by a reader on this blog. This is along with Pine Island Glacier often considered the weak underbelly of the ice sheet. MODIS imagery from February, March, September and October is used here to illustrate the event. The red, magenta and green arrows point to the same location in each image. The blue dots mark the ice front. The orange arrow points to a portion of the Thwaites Glacier Ice Tongue that had previously calved in 2002/03. In the latter two images the yellow arrow indicates the new ice tongue piece that has broken off. This is an important glacier along with the A video using MODIS and Landsat imagery notes the 2012 changes and the number and size of new icebergs from the glacier. Pine Island Glacier as they both tap into the heart of the WAIS but lack big buttressing ice shelves. This is why in 1985 I was busy preparing a bedrock map in front of the glacier from two shipboard seismic transects for Tom Kellogg and Terry Hughes at U Maine. Of course that map did not look nearly as good as the recent ones in Tinto and Bell (2011), from the extensive NASA Operation Icebridge. What they indicate in the two following images from their paper is that the new ice tongue before it broke off was ending on top of a bedrock high (red arrow first image below), that would act as pinning for the ice tongue. The thicker the ice at that point the better the pinning point. This bedrock high is noted in the 3-d with a white arrow. Kirsty Tinto and Robin Bell (2011) of Colubmia University, also did predict a faster retreat for Thwaites Glacier. Rignot et al (2002) noted that the Thwaites Glacier grounding line was in retreat, the mass loss was increasing and the glacier was thinning, though not nearly as fast as Pine Island Glacier. In the last image below from Rignot (2008) the velocity of Pine Island Glacier and Thwaites Glacier is shown, the high velocity region of Thwaites is wider, and this has been expanding ((Rignot et al, 2002). The Thwaites Glacier behavior ice frontal changes and thinning is like the Smith Glacier to its west also. Unlike Petermann Glacier where there is no past history to suggest the terminus will readvance significantly towards its former position, Thwaites Glacier has experienced large calving events in the past, such as 2002/03. The difference on this occasion is that the ice tongue was quite small and hence more stable than in previous calving event occasions. The continued thinning makes the readvance and subsequent pinning on the bedrock ridge less likely. The rifting is also quite extensive as MacGregor et al (2012) had noted, I look forward to the observations that will emerge from NASA’s Operation Ice Bridge in Antarctica that begins in a week.