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The Domino Effect

Tracking Antarctica's Ice Shelves - Mon, 11/14/2016 - 22:45
Along the edge of the Antarctic Peninsula. (photo M. Turrin)

Along the edge of the Antarctic Peninsula, large chunks of ice flow freely from the land into the ocean. Photo: M. Turrin

Ice shelves can behave like dominos. When they are lined up and the first one collapses it can cause a rippling effect like dominos. We have seen this with the Larsen ice shelves. Named in series, the Larsen A, B and C shelves extended along the northeastern edge of the West Antarctic Peninsula, and covered a large swath of coastline as recently as 20 years ago. Bordering the western edge of the Weddell Sea, each extended from a separate embayment yet merged into a large expanse of ice, considered one ice shelf complex. All this was before 1995, before the dominoes began to collapse.

Glacier on the Antarctic Peninsula moving. (Photo M. Turrin)

In this area of the Antarctic Peninsula, ice moves as if it is on a conveyor belt, flowing down between the mountain peaks and toward the ocean. You can see here it is building an ice moraine as it flows. This stretch of glaciers flows onto the Larsen catchment. Photo: M. Turrin

It was January 1995, toward the end of the austral summer, when Larsen A, the smallest of the three shelves, broke apart rather suddenly and was gone. The furthest north of the Larsen trio, this small shelf was situated just north of the Larsen B and just outside of the Antarctic Circle. Due to its size and location, the 1,500-square-kilometer block of ice was the most vulnerable of the three Larsen shelves. Warming water that had been moving around the peninsula was the probable cause for the demise.

The Larsen ice shelf complex, as it was and what it is now. (Images from NASA, compilation from Carbon Copy)

The Larsen ice shelf complex. Images: NASA; compilation: Carbon Copy

When Larsen A disappeared, Larsen B immediately became more vulnerable. Although twice the size at 3,250 square kilometers, the shelf was now un-buffered from warming ocean waters to the north; this combined with several warm summers and Larsen B weakened and became destabilized. In 1998, satellites captured evidence of the front edge of Larsen B beginning to change. Satellite images pointed out melt water ponds on the surface of the shelf, but with some 220 meters of ice thickness, these ponds did not seem to pose a threat. Then between early February and early March 2002, the shelf suffered a massive collapse, with section after section all but evaporating before our eyes. There was disbelief among the science community that a section of shelf this size, and one that had been relatively stable for an estimated 10,000-12,000 years, could so swiftly suffer a collapse. The second domino had fallen.

The Antarctic Peninsula has elevation rising 8000 ft. with ice covering the tops of the mountains in thick layers. (Photo M. Turrin)

The Antarctic Peninsula has elevation rising 8,000 ft., with ice covering the tops of the mountains in thick layers. Photo: M. Turrin

With the loss of a significant section of the Larsen shelf complex, there was a subsequent acceleration of the glaciers that had once been braced by the shelves’ protective presence. Without the stable pressure pushing back against these glaciers, the ice sheet in this area accelerated by up to 300 percent, transferring ice from the Antarctic continent into the ocean and contributing more ice to sea level rise. With the acceleration came a rapid loss in size in the glaciers feeding the Larsen area.

Larsen C and the crack that has developed mapped through time. (Modis imagery annotated by the MIDAS project.)

Larsen C and the crack that has developed, mapped through time. Image: Modis imagery annotated by the MIDAS project

Larsen C remains the fourth largest of the ice shelves by a few hundred square kilometers of ice. A crack appeared in the shelf in 2011 and has grown in size over the subsequent years. Set back about 20 kms. from the edge of the shelf, it threatens to break off about 8 percent of the shelf, or a chunk of ice about the same size as the state of Delaware, at ~6,000 sq. km. With the crack set so far back, there is concern that it might threaten the integrity of the larger ice sheet, weakening the support that holds the shelf in place.

Crack in the Larsen C Ice Shelf that continues to spread, even in the winter months. (Photo M. Turrin)

Crack in the Larsen C Ice Shelf that continues to spread, even in the winter months. Photo: M. Turrin

Just as Larsen B revealed the speed with which an ice shelf can collapse, Larsen C may be poised to reveal how quickly a large crack can propagate along the shelf. The rift is growing even during the Antarctic winter, adding an additional 22 kms. to a length of 130 kms. in total during the last austral winter between March and August 2016. In addition, the crack has widened from 200 meters to 350 meters. Overflying the crack, we were able to collect high resolution imagery that will help with tracking the fate of the third domino in the lineup.

Section of the deep crack in the Larsen C ice shelf. (Digital Mapping System from the IceBridge Project.)

A section of the deep crack in the Larsen C ice shelf collected by high resolution imagery using the Digital Mapping System as part of the IceBridge Project. Photo: DMS team, IceBridge

IceBridge: Since 2009, the NASA IceBridge project has brought together science teams to monitor and measure each of the ice features in order to improve our understanding of changes in the climate system and our models. Lamont-Doherty, under lead scientists Jim Cochran and Kirsty Tinto, has led up the gravity and magnetics measurements for these campaigns.

http://www.ldeo.columbia.edu/icebridge

http://www.ldeo.columba.edu/rosetta

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The Domino Effect

Ice Bridge Blog - Mon, 11/14/2016 - 22:45
Along the edge of the Antarctic Peninsula. (photo M. Turrin)

Along the edge of the Antarctic Peninsula, large chunks of ice flow freely from the land into the ocean. Photo: M. Turrin

Ice shelves can behave like dominos. When they are lined up and the first one collapses it can cause a rippling effect like dominos. We have seen this with the Larsen ice shelves. Named in series, the Larsen A, B and C shelves extended along the northeastern edge of the West Antarctic Peninsula, and covered a large swath of coastline as recently as 20 years ago. Bordering the western edge of the Weddell Sea, each extended from a separate embayment yet merged into a large expanse of ice, considered one ice shelf complex. All this was before 1995, before the dominoes began to collapse.

Glacier on the Antarctic Peninsula moving. (Photo M. Turrin)

In this area of the Antarctic Peninsula, ice moves as if it is on a conveyor belt, flowing down between the mountain peaks and toward the ocean. You can see here it is building an ice moraine as it flows. This stretch of glaciers flows onto the Larsen catchment. Photo: M. Turrin

It was January 1995, toward the end of the austral summer, when Larsen A, the smallest of the three shelves, broke apart rather suddenly and was gone. The furthest north of the Larsen trio, this small shelf was situated just north of the Larsen B and just outside of the Antarctic Circle. Due to its size and location, the 1,500-square-kilometer block of ice was the most vulnerable of the three Larsen shelves. Warming water that had been moving around the peninsula was the probable cause for the demise.

The Larsen ice shelf complex, as it was and what it is now. (Images from NASA, compilation from Carbon Copy)

The Larsen ice shelf complex. Images: NASA; compilation: Carbon Copy

When Larsen A disappeared, Larsen B immediately became more vulnerable. Although twice the size at 3,250 square kilometers, the shelf was now un-buffered from warming ocean waters to the north; this combined with several warm summers and Larsen B weakened and became destabilized. In 1998, satellites captured evidence of the front edge of Larsen B beginning to change. Satellite images pointed out melt water ponds on the surface of the shelf, but with some 220 meters of ice thickness, these ponds did not seem to pose a threat. Then between early February and early March 2002, the shelf suffered a massive collapse, with section after section all but evaporating before our eyes. There was disbelief among the science community that a section of shelf this size, and one that had been relatively stable for an estimated 10,000-12,000 years, could so swiftly suffer a collapse. The second domino had fallen.

The Antarctic Peninsula has elevation rising 8000 ft. with ice covering the tops of the mountains in thick layers. (Photo M. Turrin)

The Antarctic Peninsula has elevation rising 8,000 ft., with ice covering the tops of the mountains in thick layers. Photo: M. Turrin

With the loss of a significant section of the Larsen shelf complex, there was a subsequent acceleration of the glaciers that had once been braced by the shelves’ protective presence. Without the stable pressure pushing back against these glaciers, the ice sheet in this area accelerated by up to 300 percent, transferring ice from the Antarctic continent into the ocean and contributing more ice to sea level rise. With the acceleration came a rapid loss in size in the glaciers feeding the Larsen area.

Larsen C and the crack that has developed mapped through time. (Modis imagery annotated by the MIDAS project.)

Larsen C and the crack that has developed, mapped through time. Image: Modis imagery annotated by the MIDAS project

Larsen C remains the fourth largest of the ice shelves by a few hundred square kilometers of ice. A crack appeared in the shelf in 2011 and has grown in size over the subsequent years. Set back about 20 kms. from the edge of the shelf, it threatens to break off about 8 percent of the shelf, or a chunk of ice about the same size as the state of Delaware, at ~6,000 sq. km. With the crack set so far back, there is concern that it might threaten the integrity of the larger ice sheet, weakening the support that holds the shelf in place.

Crack in the Larsen C Ice Shelf that continues to spread, even in the winter months. (Photo M. Turrin)

Crack in the Larsen C Ice Shelf that continues to spread, even in the winter months. Photo: M. Turrin

Just as Larsen B revealed the speed with which an ice shelf can collapse, Larsen C may be poised to reveal how quickly a large crack can propagate along the shelf. The rift is growing even during the Antarctic winter, adding an additional 22 kms. to a length of 130 kms. in total during the last austral winter between March and August 2016. In addition, the crack has widened from 200 meters to 350 meters. Overflying the crack, we were able to collect high resolution imagery that will help with tracking the fate of the third domino in the lineup.

Section of the deep crack in the Larsen C ice shelf. (Digital Mapping System from the IceBridge Project.)

A section of the deep crack in the Larsen C ice shelf collected by high resolution imagery using the Digital Mapping System as part of the IceBridge Project. Photo: DMS team, IceBridge

IceBridge: Since 2009, the NASA IceBridge project has brought together science teams to monitor and measure each of the ice features in order to improve our understanding of changes in the climate system and our models. Lamont-Doherty, under lead scientists Jim Cochran and Kirsty Tinto, has led up the gravity and magnetics measurements for these campaigns.

http://www.ldeo.columbia.edu/icebridge

http://www.ldeo.columba.edu/rosetta

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In Bangladesh, Arsenic Poisoning Is a Neglected Issue - The Lancet

Featured News - Sat, 11/12/2016 - 12:00
Millions of people in Bangladesh are still being exposed to arsenic in their drinking water, decades after the problem was identified. The Lancet talks with Lamont's Lex van Geen about his work on arsenic in drinking water in South Asia.

How Did Climate and Humans Respond to Past Volcanic Eruptions? - Eos

Featured News - Fri, 11/11/2016 - 10:00
To predict and prepare for future climate change, scientists are striving to understand how global-scale climatic change manifests itself on regional scales and also how societies adapt—or don’t—to sometimes subtle and complex climatic changes.These issues were at the heart of the inaugural workshop of the Volcanic Impacts on Climate and Society (VICS) Working Group, convened at Lamont-Doherty Earth Observatory.

A first meeting with an old friend

Tracking Antarctica's Ice Shelves - Thu, 11/10/2016 - 22:09
Pine Island Ice Shelf

As we fly over Pine Island Glacier, West Antarctica the blowing snow adds a surreal quality to the 200 ft. high towering edge of the ice shelf. (Photo M. Turrin)

If you have studied the impacts of climate on Antarctica you have encountered Pine Island Glacier. Tucked in at an angle under the West Antarctic Peninsula handle, this seemingly innocuous glacier has been making headlines for years as one of the fastest flowing ice stream glaciers on Earth. In Antarctica, Pine Island pushes ice at a rapid clip into Pine Island Bay part of the larger Amundsen Sea. So although we have never met face to face, Pine Island is a glacier I have known for years.

Antarctica has two large ice sheets, sensibly labeled the West Antarctic Ice Sheet and the East Antarctica Ice Sheet and separated by the looming Transantarctic Mountains that break through above the thick layer of ice covering much of Antarctic’s surface. In large part West Antarctica is comprised of the Antarctic Peninsula, the handle shaped extension of the continent reaching out towards South America, but below that there is a vulnerable area that drains into Amundsen Sea, one of three catchment areas for this ice sheet. Glaciers in this region have been changing rapidly, led by Pine Island and the neighboring Thwaites. If melted, the ice from Pine Island and Thwaites glaciers together, has the capacity to raise global sea level by up to 2 meters (~7 feet.)

velocity map

The red color represents the fast moving ice of Pine Island glacier in this velocity map on the left. On the left side is a map of subglacial topography showing in dark blue the deep trough that underlies the glacier. (credit velocity map E. Rignot)

For Pine Island the vulnerability results from a compounding of challenges, a small ice shelf offering little support to the land ice behind and little protection from the warming ocean water that makes its way up onto the shelf. In addition the base of the glacier rests on land that is backward sloping, or tipping back underneath the ice. A retrograde bed, as these are called, allows the warm ocean water access to move back under the glacier, further destabilizing and acceleration ice flow.

Crevassing in the ice shows areas where there is strain from ice flowing at different rates. Ice will often crevasse as it accelerates. (Photo M. Turrin)

Crevassing, or deep cuts in the ice, shows areas where there is strain from ice flowing at different rates. Ice will often crevasse as it accelerates, as is shown in this heavily crevassed ice flowing out from the Pine Island ice shelf.  (Photo M. Turrin)

At 160 miles of length, and 68,000 square miles of catchment, Pine Island handles the drainage for approximately one tenth of the West Antarctic Ice Sheet. Over the last forty years it has been over-performing, accelerating its flow, and is attributed with one quarter of Antarctica’s current ice loss. In its years of operation (2003-2010), Ice Sat I satellite  provided us with a series of measurements for this glacier showing that Pine Island Glacier was moving more ice into the ocean than any other drainage basin worldwide. Since 2009 the IceBridge project has continued this monitoring, extending our data for this region so that we won’t miss critical information while IceSat II is being prepared for a 2018 launch. Pine Island glacier measurements are critically important to help us project global sea level rise.

On the DC8

On board the DC8 there is a flight command center with a very busy team that works between the science team and the air crew to ensure the science is completed safely and as designed. (photo M. Turrin)

Pine Island glacier is shrinking. As the glacier has accelerated its flow, the ice stream has thinned and correspondingly the face of the glacier has lost elevation. In some areas ice elevation loss has equaled 4 meters or more a year. The drop in elevation is more  quadruple the annual precipitation for the area, and has occurred in both summer and winter.

Crevasse

Ice Bridge laser image of the crack in Pine Island Glacier. The deep blue line bisecting the front of the glacier is the crack or crevasse in the ice. The depth of the crack that cuts in from the edge of the ice shelf is close to 40 meters deep in this area. (image NASA IceBridge)

More bad news may be ahead for Pine Island. Although the glacier does not have a large ice shelf, there is a relatively small shelf that helps to restrain some of the flow from land to ocean. However, in the last decade a fairly significant crack has developed in the shelf threatening to pull off another large chunk of ice and relaxing the hold the shelf has on the ice behind. As we overflew two locations IceBridge surface laser measurements captured the crack depth at 60 and 70 meters deep. This crack has continued to expand over the last few years and it is only a matter of time before this section of shelf will separate moving off into the ocean and leaving the ice shelf more exposed.

The Pine Island Glacier crack extending back into the glacier. (Photo M. Turrin)

The Pine Island Glacier crack extending back into the glacier. (Photo M. Turrin)

IceBridge: Since 2009, the NASA IceBridge project has brought together science teams to monitor and measure each of the ice features in order to improve our understanding of changes in the climate system and our models. Lamont-Doherty, under lead scientists Jim Cochran and Kirsty Tinto, has led up the gravity and magnetics measurements for these campaigns.

http://www.ldeo.columbia.edu/icebridge

http://www.ldeo.columba.edu/rosetta

A first meeting with an old friend

Ice Bridge Blog - Thu, 11/10/2016 - 22:09
Pine Island Ice Shelf

As we fly over Pine Island Glacier, West Antarctica the blowing snow adds a surreal quality to the 200 ft. high towering edge of the ice shelf. (Photo M. Turrin)

If you have studied the impacts of climate on Antarctica you have encountered Pine Island Glacier. Tucked in at an angle under the West Antarctic Peninsula handle, this seemingly innocuous glacier has been making headlines for years as one of the fastest flowing ice stream glaciers on Earth. In Antarctica, Pine Island pushes ice at a rapid clip into Pine Island Bay part of the larger Amundsen Sea. So although we have never met face to face, Pine Island is a glacier I have known for years.

Antarctica has two large ice sheets, sensibly labeled the West Antarctic Ice Sheet and the East Antarctica Ice Sheet and separated by the looming Transantarctic Mountains that break through above the thick layer of ice covering much of Antarctic’s surface. In large part West Antarctica is comprised of the Antarctic Peninsula, the handle shaped extension of the continent reaching out towards South America, but below that there is a vulnerable area that drains into Amundsen Sea, one of three catchment areas for this ice sheet. Glaciers in this region have been changing rapidly, led by Pine Island and the neighboring Thwaites. If melted, the ice from Pine Island and Thwaites glaciers together, has the capacity to raise global sea level by up to 2 meters (~7 feet.)

velocity map

The red color represents the fast moving ice of Pine Island glacier in this velocity map on the left. On the left side is a map of subglacial topography showing in dark blue the deep trough that underlies the glacier. (credit velocity map E. Rignot)

For Pine Island the vulnerability results from a compounding of challenges, a small ice shelf offering little support to the land ice behind and little protection from the warming ocean water that makes its way up onto the shelf. In addition the base of the glacier rests on land that is backward sloping, or tipping back underneath the ice. A retrograde bed, as these are called, allows the warm ocean water access to move back under the glacier, further destabilizing and acceleration ice flow.

Crevassing in the ice shows areas where there is strain from ice flowing at different rates. Ice will often crevasse as it accelerates. (Photo M. Turrin)

Crevassing, or deep cuts in the ice, shows areas where there is strain from ice flowing at different rates. Ice will often crevasse as it accelerates, as is shown in this heavily crevassed ice flowing out from the Pine Island ice shelf.  (Photo M. Turrin)

At 160 miles of length, and 68,000 square miles of catchment, Pine Island handles the drainage for approximately one tenth of the West Antarctic Ice Sheet. Over the last forty years it has been over-performing, accelerating its flow, and is attributed with one quarter of Antarctica’s current ice loss. In its years of operation (2003-2010), Ice Sat I satellite  provided us with a series of measurements for this glacier showing that Pine Island Glacier was moving more ice into the ocean than any other drainage basin worldwide. Since 2009 the IceBridge project has continued this monitoring, extending our data for this region so that we won’t miss critical information while IceSat II is being prepared for a 2018 launch. Pine Island glacier measurements are critically important to help us project global sea level rise.

On the DC8

On board the DC8 there is a flight command center with a very busy team that works between the science team and the air crew to ensure the science is completed safely and as designed. (photo M. Turrin)

Pine Island glacier is shrinking. As the glacier has accelerated its flow, the ice stream has thinned and correspondingly the face of the glacier has lost elevation. In some areas ice elevation loss has equaled 4 meters or more a year. The drop in elevation is more  quadruple the annual precipitation for the area, and has occurred in both summer and winter.

Crevasse

Ice Bridge laser image of the crack in Pine Island Glacier. The deep blue line bisecting the front of the glacier is the crack or crevasse in the ice. The depth of the crack that cuts in from the edge of the ice shelf is close to 40 meters deep in this area. (image NASA IceBridge)

More bad news may be ahead for Pine Island. Although the glacier does not have a large ice shelf, there is a relatively small shelf that helps to restrain some of the flow from land to ocean. However, in the last decade a fairly significant crack has developed in the shelf threatening to pull off another large chunk of ice and relaxing the hold the shelf has on the ice behind. As we overflew two locations IceBridge surface laser measurements captured the crack depth at 60 and 70 meters deep. This crack has continued to expand over the last few years and it is only a matter of time before this section of shelf will separate moving off into the ocean and leaving the ice shelf more exposed.

The Pine Island Glacier crack extending back into the glacier. (Photo M. Turrin)

The Pine Island Glacier crack extending back into the glacier. (Photo M. Turrin)

IceBridge: Since 2009, the NASA IceBridge project has brought together science teams to monitor and measure each of the ice features in order to improve our understanding of changes in the climate system and our models. Lamont-Doherty, under lead scientists Jim Cochran and Kirsty Tinto, has led up the gravity and magnetics measurements for these campaigns.

http://www.ldeo.columbia.edu/icebridge

http://www.ldeo.columba.edu/rosetta

Non-Profit, Lamont Team Up for Sustainability Program - Orangetown Daily Voice

Featured News - Wed, 11/09/2016 - 17:07
Students from nine Rockland County high schools will get hands-on experience at land use planning at collaborative workshops with Columbia University's Lamont-Doherty Earth Observatory and Rockland Conservation Service Corps.

Poaching on the Rise — Most Illegal Ivory Comes from Recently Killed Elephants - The Verge

Featured News - Wed, 11/09/2016 - 16:55
Almost all the world’s illegal ivory comes from elephants that have been recently killed, according to a new study from Lamont's Kevin Uno.

Recently Killed Elephants Are Fueling the Ivory Trade - Science Magazine

Featured News - Mon, 11/07/2016 - 12:00
The illegal trade in elephant ivory is being fueled almost entirely by recently killed African elephants, not by tusks leaked from old government stockpiles, as had long been suspected. That’s the conclusion of a new study from Lamont's Kevin Uno that relies on nuclear bomb tests carried out in the 1950s and ’60s to date elephant tusks.

Year by Year, Line by Line, We Build an Image of Getz Ice Shelf

Ice Bridge Blog - Sun, 11/06/2016 - 16:16
Grease Ice

Newly formed sea ice called “grease ice” looks like thin layers of mica along the front of the Getz Ice Shelf, Antarctica. Photo: M. Turrin

Antarctic ice appears in a range of types and sizes, from the newly formed skim of ice on the ocean called grease ice (above), to the older meter thick layers of sea ice, to chunks of icebergs, floating reaches of ice shelves, and finally the massive land based Antarctic ice sheet. Each part of this ice inventory has a unique role in the larger climate system, but they also work together. As part of this year’s IceBridge Antarctic flight campaign, we are focused largely on the coastline to build a better understanding of the interaction of these different pieces in the ice system. This understanding is central to improving our climate models.

Break in Ice Shelf

Evidence of a break along the front edge of Getz Ice Shelf, Antartica. In the foreground a mixture of newly forming sea ice has mixed with icebergs to form what is called “brash ice.” Photo: M. Turrin

The focus today is on Getz ice shelf. Ice shelves form when ice flows off the land into the surrounding ocean, forming a thick apron of attached, but floating ice. The Getz shelf extends out several miles from where the glacier empties into the ocean. The shelves are deep floating blocks of ice ~ a km thick where they first meet the ocean and thinned to several hundred meters thick at their front edge. They are critical for the future stability of the Antarctic ice sheet as they provide a barrier that holds back the continental ice sheet, braking its flow from land into the ocean.

Image noting the location of some of the larger ice shelves around Antarctica (Image T. Scambos NSIDC)

Image noting the location and size of  a dozen or so of the larger ice shelves around Antarctica. Image: T. Scambos NSIDC

In all ~ 45 ice shelves adorn almost half the Antarctica coastline, and represent an area of ~1.5 million km², close to 10 percent of the total ice that covers Antarctica. Ten of these are considered major shelves, with the largest two nestled in the junctures where East and West Antarctic meet, filling in the space with California-sized blocks of ice: the Ross Ice Shelf (at 472,960 km²), where Lamont-Doherty currently has another Antarctic research project called Rosetta running, and the Filchner-Ronne (422,420 km²) across from it. Many of the shelves are smaller, yet each serves a valuable role in Antarctic ice stability, and thus they are a prime focus for examining change in Antarctica.

Tabular icebergs after separating fro the ice shelf line up along the front of Getz before moving out into the ocean. (Photo M. Turrin)

Large tabular icebergs after separating from the ice shelf line up along the front of Getz before moving out into the ocean. Photo: M. Turrin

Changes in Antarctic ice have been dominated by the interaction of the ice and the ocean, and because ice shelves extend out into the water, they are vulnerable to melt from the warmer ocean water. Melt can affect them in two ways, through thinning along their length and through causing a retreat of the “grounding line.”  The grounding line is the critical spot where the ice goes from being frozen all the way to the ocean floor (or bed) to where it begins to float in the ocean. The grounding line retreat results from warm water melting the ice back from its frozen base. Tracking any changes to the location of the grounding line tells us a lot about the vulnerability of the ice shelf and is critical to setting models.

Ice shelves sit primarily below the ocean surface. Getz measures close to 200 ft. at the front but with another 1000 ft. below the surface. The rich blue color along the front edge is from that deep reaching ice front. (Photo M. Turrin)

Ice shelves sit primarily below the ocean surface. Getz measures close to 200 ft. elevation above the ocean at the front, but has another 1000 ft. of ice below the surface. The rich blue color along the front edge is from that deep reaching ice front. Photo: M. Turrin

Getz ice shelf is our furthest flight mission of the campaign at close to 12 hours of flying, and it is our fifth mission this week, with each one clocking 11 plus hours of flight with prep and wrap-up added on either end. It could feel a bit like a rerun of the same movie, but it never does, and the wear of the long days doesn’t appear to show on the team. The purpose of today is to continue mapping the sub ice-shelf bathymetry using our gravimeter, as well as the ice surface and bedrock upstream of the grounding line using laser and radar. We need a complete look at the grounding line and the bed under the ice shelf, where warm ocean water can move in and circulate under the ice, in order to improve our models. Gravity is critical for uncovering the surface depths and contours under the ice shelves, as none of the other instruments on board are able to collect data through the water that lies under the shelf.

Mountain Protrusion

A set of mountains protrudes up through the ice at the west end of the survey line along the edge of the Getz Ice Shelf. Photo: M. Turrin

Because of the distance to Getz from our daily starting point in Chile, we have been building a set of data over a series of years, line by line. Each year we collect a repeat track and a new track. We know Getz has changed. Eighteen months ago in March 2015, a NASA image from space captured a Manhattan-sized iceberg (17 miles long) breaking off of Getz Ice Shelf. This break appears to have occurred at the end of the last austral summer in late February. Today we can see large sections of ice that will soon be calving, but what this means will need to be matched to the other measurements we are collecting before we know the full set of changes in Getz.

IceBridge: Since 2009, the NASA IceBridge project has brought together science teams to monitor and measure each of the ice features in order to improve our understanding of changes in the climate system and our models. Lamont-Doherty, under lead scientists Jim Cochran and Kirsty Tinto, has led up the gravity and magnetics measurements for these campaigns. This season alone, the project has logged 195 hours of flight time to date, and flown an equivalent of a third of the way to the moon.

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Year by Year, Line by Line, We Build an Image of Getz Ice Shelf

Tracking Antarctica's Ice Shelves - Sun, 11/06/2016 - 16:16
Grease Ice

Newly formed sea ice called “grease ice” looks like thin layers of mica along the front of the Getz Ice Shelf, Antarctica. Photo: M. Turrin

Antarctic ice appears in a range of types and sizes, from the newly formed skim of ice on the ocean called grease ice (above), to the older meter thick layers of sea ice, to chunks of icebergs, floating reaches of ice shelves, and finally the massive land based Antarctic ice sheet. Each part of this ice inventory has a unique role in the larger climate system, but they also work together. As part of this year’s IceBridge Antarctic flight campaign, we are focused largely on the coastline to build a better understanding of the interaction of these different pieces in the ice system. This understanding is central to improving our climate models.

Break in Ice Shelf

Evidence of a break along the front edge of Getz Ice Shelf, Antartica. In the foreground a mixture of newly forming sea ice has mixed with icebergs to form what is called “brash ice.” Photo: M. Turrin

The focus today is on Getz ice shelf. Ice shelves form when ice flows off the land into the surrounding ocean, forming a thick apron of attached, but floating ice. The Getz shelf extends out several miles from where the glacier empties into the ocean. The shelves are deep floating blocks of ice ~ a km thick where they first meet the ocean and thinned to several hundred meters thick at their front edge. They are critical for the future stability of the Antarctic ice sheet as they provide a barrier that holds back the continental ice sheet, braking its flow from land into the ocean.

Image noting the location of some of the larger ice shelves around Antarctica (Image T. Scambos NSIDC)

Image noting the location and size of  a dozen or so of the larger ice shelves around Antarctica. Image: T. Scambos NSIDC

In all ~ 45 ice shelves adorn almost half the Antarctica coastline, and represent an area of ~1.5 million km², close to 10 percent of the total ice that covers Antarctica. Ten of these are considered major shelves, with the largest two nestled in the junctures where East and West Antarctic meet, filling in the space with California-sized blocks of ice: the Ross Ice Shelf (at 472,960 km²), where Lamont-Doherty currently has another Antarctic research project called Rosetta running, and the Filchner-Ronne (422,420 km²) across from it. Many of the shelves are smaller, yet each serves a valuable role in Antarctic ice stability, and thus they are a prime focus for examining change in Antarctica.

Tabular icebergs after separating fro the ice shelf line up along the front of Getz before moving out into the ocean. (Photo M. Turrin)

Large tabular icebergs after separating from the ice shelf line up along the front of Getz before moving out into the ocean. Photo: M. Turrin

Changes in Antarctic ice have been dominated by the interaction of the ice and the ocean, and because ice shelves extend out into the water, they are vulnerable to melt from the warmer ocean water. Melt can affect them in two ways, through thinning along their length and through causing a retreat of the “grounding line.”  The grounding line is the critical spot where the ice goes from being frozen all the way to the ocean floor (or bed) to where it begins to float in the ocean. The grounding line retreat results from warm water melting the ice back from its frozen base. Tracking any changes to the location of the grounding line tells us a lot about the vulnerability of the ice shelf and is critical to setting models.

Ice shelves sit primarily below the ocean surface. Getz measures close to 200 ft. at the front but with another 1000 ft. below the surface. The rich blue color along the front edge is from that deep reaching ice front. (Photo M. Turrin)

Ice shelves sit primarily below the ocean surface. Getz measures close to 200 ft. elevation above the ocean at the front, but has another 1000 ft. of ice below the surface. The rich blue color along the front edge is from that deep reaching ice front. Photo: M. Turrin

Getz ice shelf is our furthest flight mission of the campaign at close to 12 hours of flying, and it is our fifth mission this week, with each one clocking 11 plus hours of flight with prep and wrap-up added on either end. It could feel a bit like a rerun of the same movie, but it never does, and the wear of the long days doesn’t appear to show on the team. The purpose of today is to continue mapping the sub ice-shelf bathymetry using our gravimeter, as well as the ice surface and bedrock upstream of the grounding line using laser and radar. We need a complete look at the grounding line and the bed under the ice shelf, where warm ocean water can move in and circulate under the ice, in order to improve our models. Gravity is critical for uncovering the surface depths and contours under the ice shelves, as none of the other instruments on board are able to collect data through the water that lies under the shelf.

Mountain Protrusion

A set of mountains protrudes up through the ice at the west end of the survey line along the edge of the Getz Ice Shelf. Photo: M. Turrin

Because of the distance to Getz from our daily starting point in Chile, we have been building a set of data over a series of years, line by line. Each year we collect a repeat track and a new track. We know Getz has changed. Eighteen months ago in March 2015, a NASA image from space captured a Manhattan-sized iceberg (17 miles long) breaking off of Getz Ice Shelf. This break appears to have occurred at the end of the last austral summer in late February. Today we can see large sections of ice that will soon be calving, but what this means will need to be matched to the other measurements we are collecting before we know the full set of changes in Getz.

IceBridge: Since 2009, the NASA IceBridge project has brought together science teams to monitor and measure each of the ice features in order to improve our understanding of changes in the climate system and our models. Lamont-Doherty, under lead scientists Jim Cochran and Kirsty Tinto, has led up the gravity and magnetics measurements for these campaigns. This season alone, the project has logged 195 hours of flight time to date, and flown an equivalent of a third of the way to the moon.

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Climate and Homo Sapiens Migration during the Last Ice Age - The John Batchelor Show

Featured News - Fri, 11/04/2016 - 07:19
John Batchelor talks with Lamont's Peter de Menocal about the timing of when Homo sapiens began migrating from Africa.

Sand Demand at the Center of Beach Replenishment Planning - WorkBoat

Featured News - Thu, 11/03/2016 - 12:00
The federal Bureau of Ocean Energy Management is compiling and updating maps and databases about offshore sediment resources from Maine to Florida for use in post-hurricane beach replenishment. The cores from those offshore deposits are now being kept at the Lamont Core Repository.

Where Science Lives: Carlos Becerril - New York Academy of Sciences

Featured News - Wed, 11/02/2016 - 08:42
Lamont's Carlos Becerril talks with the New York Academy of Sciences about his team's work building ocean bottom seismometers as part of the Ocean Bottom Seismograph Instrument Pool (OBSIP).

Thousands Displaced After Italy Earthquake - CBS News

Featured News - Mon, 10/31/2016 - 15:29
A magnitude 6.6 earthquake struck Italy on Oct. 30 following two smaller earthquakes a few days earlier and a devastating earthquake there in August. “Probably it's every hundred years you get a repeat of a series of earthquakes,” Lamont's Michael Steckler told CBS News.

Water Challenges of Megacities - Eos

Featured News - Wed, 10/26/2016 - 12:00
Looking ahead to looming water quantity shortfalls, Lamont's Yan Zheng argues that using reclaimed water for managed aquifer recharge needs to play a larger role in China’s water management strategies.

Climate Change Is Fueling America’s Forest Fires - Huffington Post

Featured News - Thu, 10/20/2016 - 12:00
The wildfires that raged through the Western United States this year claimed lives, destroyed hundreds of homes and cost taxpayers millions of dollars. A new study from Columbia University's Park Williams has found that climate change has been exacerbating wildfires in the Western United States for decades.

This Antarctic Glacier May Be One of the Biggest Threats to Sea Level - Washington Post

Featured News - Thu, 10/20/2016 - 12:00
U.S. and British science agencies announced a multimillion-dollar research mission to study Antarctica's enormous Thwaites Glacier, which could hold the potential for major sea level rise this century. Getting “up close and personal” with the glacier will help researchers close critical data and knowledge gaps, said Lamont's Robin Bell.

The 11 Greatest Engineering Innovations of 2016 - Popular Science

Featured News - Wed, 10/19/2016 - 12:00
Lamont's carbon capture and storage project in Iceland that proved we could turn CO2 from a power plant to a solid mineral in a short period of time was listed among the greatest engineering innovations of 2016. The project was led by Juerg Matter and Martin Stute.

Heather Savage to Receive AGU Mineral and Rock Physics Early Career Award - Eos

Featured News - Tue, 10/18/2016 - 12:00
Lamont's Heather Savage will receive AGU's 2016 Mineral and Rock Physics Early Career Award at the 2016 American Geophysical Union Fall Meeting. The award is for promising young scientists in recognition of outstanding contributions achieved during their Ph.D. research.

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