Pine Island Glacier
| Pine Island Glacier | ||
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NASA research flight over Pine Island Glacier in November 2011 |
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| location | Ellsworthland , West Antarctica | |
| Type | Ice flow | |
| length | 250 km | |
| surface | 162,300 km² | |
| Ice thickness | ⌀ 2000 m | |
| Coordinates | 75 ° 10 ′ S , 100 ° 0 ′ W | |
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| drainage | Pine Island Bay | |
The Pine Island Glacier ( English Pine Island Glacier , abbreviated PIG ) is a significant ice flow in Ellsworthland in West Antarctica . The glaciated catchment area has an area of 162,300 km², the ice masses of the glacier system make up around 10% of the West Antarctic ice sheet . The Pine Island Glacier extends from the Hudson Mountains to Pine Island Bay in the southern Amundsen Sea , where it forms an ice shelf .
The Pine Island Glacier transports more ice into the ocean than any other glacier in the world. Since the glacier had a clearly negative mass balance in recent years , this contribution has increased. The ice thickness of the glacier, which is estimated to be about two kilometers, decreases by about one meter every year. This makes the glacier the world's most rapidly shrinking in terms of total mass loss.
The glacier has retreated significantly over the past 20 years. The so-called grounding line , i.e. the line from which the ice begins to swim on the sea, has shifted around 20 kilometers towards the coast during this period. Simulations of a study published in 2014 suggest that the retreat will intensify significantly in the next few years due to the relief on the seabed, resulting in an annual mass loss that is five times as large. With this predicted loss of mass, this glacier alone will cause the sea level to rise by 3.5 to 10 mm within the next 20 years.
development
Currently (2014) the Pine Island Glacier is responsible for 20% of the mass loss of the West Antarctic Ice Sheet . The accelerated loss of thickness observed since the 1980s is attributed to subglacial melting at the bottom of the ice shelf, which has been intensified by the recent intensification of circumpolar deep water circulation .
From 1992 to 2011, an annual retraction of the grounding line of 0.95 ± 0.09 km was measured on the basis of satellite images. It should be noted that the increasingly steeper sloping seabed in the retreat area should actually have counteracted a retreat of the grounding line. It is assumed that the melting processes in the sea and the thinning of the ice shelf mean that the end of the glacier offers less resistance to the ice flow and is therefore also responsible for the thinning of the continental part of the glacier.
In October 2011, the glacier attracted attention when a 30 km long crack formed in the ice shelf 20 km behind the calving front . This led to the formation of an iceberg with an area of around 720 km² on July 8, 2013 , which drifted into the Amundsen Sea. Such a process is not uncommon in such a glacier and not necessarily due to global warming.
In 2014, the grounding line was at a point where the seabed does not rise towards the coast, but instead falls off again. The past has shown that such a constellation can lead to the destabilization of tidal glaciers . Three different simulations for the Pine Island Glacier came to the result that the Pine Island Glacier will retreat another 40 kilometers quite quickly. According to these simulations, the annual mass loss of the glacier, which had been 20 gigatons per year from 1992 to 2011, will amount to 100 gigatons per year in the next 20 years - this corresponds to a sea level rise of 3.5 to 10 mm during this period. In the following years, according to these simulations, the loss of mass remains at a high level of 60 to 120 gigatons per year. Another study published in 2014 made it clear that the Pine Island Glacier is very sensitive to climate change. While in 2010 the glacier transported around 69 cubic kilometers of ice into the sea as meltwater, in 2012 it released around 35 cubic kilometers of only about half of the meltwater. The sharp decline in 2012 was probably due to the significant cooling of the Amundsen Sea. This was caused by the prevailing easterly winds, which were caused by a strong La Niña effect . Usually westerly winds are prevalent in this area.
In 2015 and 2017, two more large icebergs broke off the ice shelf. For a long time now, the edge has been shifting more and more towards the land. The glacier is considered destabilized; in 2017 its flow rate increased to 2.5 miles per year. The glacier loses 45 billion tons of ice every year.
In 2018, scientists at the University of Rhode Island's Graduate School of Oceanography published a study that found a significant volcanic heat source beneath the ice in the upper part of the glacier, likely in the Hudson Mountains . This volcano erupted 2200 years ago. While the majority of the observed melting is not caused by this volcanism, but is an effect of global warming, volcanism should nevertheless be taken into account as an additional factor in future scenarios: Magma flows could change within the volcanically active region; or the decreasing load of the melting ice sheet could increase volcanic activity. Already in 1993, a possible influence of the local volcanic activity on the stability of the ice sheet was pointed out.
Web links
- NASA Earth Observatory: New Images of the Pine Island Glacier ( September 24, 2008 memento in the Internet Archive ) January 2008
Individual evidence
- ↑ David G. Vaughan, Hugh FJ Corr, Fausto Ferraccioli, Nicholas Frearson, Aidan O'Hare, Dieter Mach, John W. Holt, Donald D. Blankenship, David L. Morse, Duncan A. Young: New boundary conditions for the West Antarctic ice sheet: Subglacial topography beneath Pine Island Glacier . In: Geophysical Research Letters. Volume 33, Issue 9, L09501, 2006 ( online )
- ↑ a b c d iSTAR - NERC: Fact file - Pine Island Glacier. Retrieved January 15, 2014
- ^ A b c L. Favier, G. Durand, SL Cornford, GH Gudmundsson, O. Gagliardini, F. Gillet-Chaulet, T. Zwinger, AJ Payne, AM Le Brocq: Retreat of Pine Island Glacier controlled by marine ice-sheet instability . In: Nature Climate Change . January 12, 2014, ISSN 1758-678X , doi : 10.1038 / nclimate2094 (English).
- ↑ JW Park, N. Gourmelen, A. Shepherd, SW Kim, DG Vaughan, DJ Wingham: Sustained retreat of the Pine Island Glacier. In: Geophysical Research Letters. Volume 40, issue 10, pp. 2137-2142, May 2013, doi: 10.1002 / grl.50379
- ^ A b Pierre Dutrieux, Jan De Rydt, Adrian Jenkins, Paul R. Holland, Ho Kyung Ha, Sang Hoon Lee, Eric J. Steig, Qinghua Ding, E. Povl Abrahamsen, Michael Schröder: Strong Sensitivity of Pine Island Ice-Shelf Melting to Climatic Variability . In: Science . tape 343 , 2004, pp. 174-177 , doi : 10.1126 / science.1244341 .
- ^ Watching the Birth of an Iceberg. NASA IceBridge Mission, November 1, 2011, accessed February 6, 2012 .
- ↑ Giant iceberg detaches from Pine Island Glacier in Antarctica . Press release of the Alfred Wegener Institute of July 9, 2013, accessed on July 10, 2013
- ↑ A key Antarctic glacier just lost a huge piece of ice - the latest sign of its worrying retreat . In: Washington Post , September 25, 2017. Retrieved September 26, 2017.
- ↑ HFJ Corr, DG Vaughan: A recent volcanic eruption beneath the West Antarctic ice sheet . In: Nature Geoscience . Vol. 1, No. 2 , 2008, p. 122–125 , doi : 10.1038 / ngeo106 , bibcode : 2008NatGe ... 1..122C (English).
- ↑ Researchers discover volcanic heat source under major Antarctic glacier . ( phys.org [accessed June 25, 2018]).
- ↑ Brice Loose et al. a .: Evidence of an active volcanic heat source beneath the Pine Island Glacier . In: Nature Communications . tape 9 , no. 2431 , 2018, doi : 10.1038 / s41467-018-04421-3 .
- ↑ Donald D. Blankenship, Robin E. Bell, Steven M. Hodge, John M. Brozena, John C. Behrendt, Carol A. Finn: Active volcanism beneath the West Antarctic ice sheet and implications for ice-sheet stability . In: Nature . tape 361 , no. 6412 , February 1993, p. 526 , doi : 10.1038 / 361526a0 .