Eric Rignot
Professor and Chair, Earth System Science | UC Irvine
Irvine, CA, UNITED STATES
Dr. Rignot works to understand the interactions of glaciers and climate and what effects they will have on global sea levels.
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Biography
Dr. Rignot works to understand the interactions of ice and climate, in particular to determine how the ice sheets in Antarctica and Greenland will respond to climate change in the coming century and how they will affect global sea level.
He uses satellite remote sensing techniques (imaging radar, laser altimetry, radio echo sounding), airborne geophysical surveys (icebridge), field surveys (radar, GPS, bathymetry, CTD), and numerical modeling (ice sheet motion, ocean circulation near glaciers, coupled ocean/ice sheet models).
In addition, he is an expert in how ice sheets in Antarctica and Greenland will respond to climate change, interactions of ice and climate, global sea level, satellite remote sensing and ocean circulation.
Areas of Expertise (4)
Ice Sheet Dynamics and Mass Balance
Climate Change
Glaciology
Radar
Accomplishments (4)
2017 Louis Agassiz Medal
Awarded to Eric Rignot for fundamental innovations in the remote sensing of glacier flow, leading to the first assessments of the mass balance of the ice sheets of Antarctica and Greenland.
NASA Outstanding Leadership Medal
2012.
Thomson Reuters Highly Cited Researcher
2014.
2007 Nobel Peace Prize (Contributing Author)
Co-author IPCC AR4.
Education (5)
Université Pierre et Marie Curie (Paris VI): Master's Degree, Astronomy and Astrophysics 1987
Ecole Centrale Paris: Engineer's Degree, Aerospace Engineering 1985
University of Southern California: Ph.D., Aerospace, Aeronautical and Astronautical Engineering 1988
University of Southern California: Master's Degree, Electrical, Electronics and Communications Engineering 1988
University of Southern California: Ph.D. and E.E., Electrical Engineering and Aeronautical Engineering 1991
Affiliations (2)
- NASA
- JPL
Links (1)
Media Appearances (33)
6 ways humans are transforming Antarctica from a pristine preserve to a polluted wasteland
Insider online
2023-09-30
Recent research found that the most intense heat wave ever recorded on Earth was in Antarctica last year. And this past winter, the frozen continent reached record-low sea ice levels. "Entire marine ecosystems are affected by such changes in sea ice cover," Eric Rignot, a professor of Earth system science at the University of California, Irvine, told Insider. …"The future of Antarctica is totally relevant to the future of humanity," Rignot said.
Martha Stewart hits back at haters after iceberg cocktail drama
Fox News online
2023-08-30
In the article, the outlet interviewed glaciologist Eric Rignot, a professor in the Earth system science department at the University of California, Irvine, who said her use of an iceberg wasn't as big an issue as others made it out to be. "It is not like she went to a glacier and carved a piece of ice off it," Rignot told The Washington Post. "Icebergs float at sea already and slowly melt. Whether they melt in the ocean or in your glass does not make a difference."
Martha Stewart put an iceberg in her drink. Experts say it’s no big deal.
The Washington Post online
2023-08-30
Perhaps, but plucking an iceberg out of the sea is not a big deal, said glaciologist Eric Rignot, a professor in the Earth system science department at the University of California at Irvine. In fact, Rignot, who studies how climate change affects the polar ice sheets, said he has done it, too. “It is not like she went to a glacier and carved a piece of ice off it,” Rignot wrote in an email to The Washington Post. “Icebergs float at sea already and slowly melt. Whether they melt in the ocean or in your glass does not make a difference.”
Antarctica has a winter sea ice shortfall four times the size of Texas
Axios online
2023-07-27
Scientists don't know what is driving the shortfall, but they are deeply concerned about its consequences, as sea ice influences the planet's climate, global ocean currents and marine ecosystems. ... It's too early to determine to what extent climate change is responsible for this year's sea ice gap, but it can not be ruled out, Eric Rignot [professor of Earth system science] of NASA's Jet Propulsion Laboratory and the University of California, Irvine told Axios.
No, Enormous Pyramid-Like Structures Have Not Been Found In Antarctica! These Are Just Mountains
Outlook India online
2023-07-31
Once again, the news that pyramid-shaped mountains were found on the Antarctic ice shelf, sparked internet speculation and excitement. ... The last word on this topic belongs to Eric Rigot, a geology [Earth system science] professor at the University of California, Irvine who provided an iconic quote on the story to LiveScience in 2016. "This is just a mountain that looks like a pyramid."
Satellites Show Warming Tides Melting a Massive Greenland Glacier
Smithsonian Magazine online
2023-05-22
Researchers studying the Petermann Glacier, one of Greenland’s biggest, have discovered a troubling melting trend that, if occurring elsewhere, could mean current estimates of sea-level rise due to shrinking glaciers should be doubled, reports the team in a new study …. “The sea water actually goes much farther beneath the grounded ice [than previously thought]—kilometers, not hundreds of meters,” senior author [Professor] Eric Rignot, an Earth system scientist at the University of California, Irvine, and a NASA research scientist, tells the Associated Press’ Seth Borenstein. “And that water is full of heat and able to melt the glaciers vigorously. And it’s kind of the most sensitive part of the glacier.”
Tides Are Eating Into Glaciers, Triggering More Melting, Study Finds
Bloomberg online
2023-05-12
A new satellite study of the Petermann Glacier in Greenland shows that its “grounding line” — where the ice transforms from a glacier in contact with the seafloor to a shelf floating above it — shifts significantly with tidal cycles. That allows warmer water to work its way into the glacier from below, according to scientists from the University of California at Irvine, NASA’s Jet Propulsion Laboratory and other institutions. … “These ice-ocean interactions make the glaciers more sensitive to ocean warming,” Eric Rignot, a co-author of the study and a professor of Earth system science at the University of California, Irvine, said in a press release. “These dynamics are not included in models, and if we were to include them, it would increase projections of sea level rise by up to 200% — not just for Petermann but for all glaciers ending in the ocean, which is most of northern Greenland and all of Antarctica.” [Subscription required, you can request an electronic copy of the article by sending an email to communications@uci.edu.]
‘Bad News’: Unexpected Melting of Greenland Glacier Could Double Sea-Level Rise Projections
EcoWatch online
2023-05-10
A glacier in the north of Greenland is melting faster and in a different way than scientists previously thought, and this has troubling implications for the future speed of global sea-level rise. The new discovery was published in the Proceedings of the National Academy of Sciences Monday. … “It’s bad news,” study author Eric Rignot, a University of California, Irvine (UCI), [professor of Earth system science and] glaciologist, told the AP. “We know the current projections are too conservative.” … “Petermann’s grounding line could be more accurately described as a grounding zone, because it migrates between 2 and 6 kilometers [approximately 1.2 to 3.7 miles] as tides come in and out,” lead author Enrico Ciraci, a UCI assistant specialist in Earth system science and NASA postdoctoral fellow, said in a statement.
Melting glacier sea level rise 'could be 200% worse than expected'
Yahoo News online
2023-05-10
Researchers at the University of California, Irvine and NASA's Jet Propulsion Laboratory said their findings could mean that the climate community has been vastly underestimating the magnitude of future sea level rise caused by polar ice deterioration. … Lead author Enrico Ciraci, UCI assistant specialist in Earth system science and NASA postdoctoral fellow said, "Petermann's grounding line could be more accurately described as a grounding zone, because it migrates between 2 and 6 kilometers (1.2 miles to 3.7 miles) as tides come in and out. This is an order of magnitude larger than expected for grounding lines on a rigid bed." … "These ice-ocean interactions make the glaciers more sensitive to ocean warming," said senior co-author Eric Rignot, UCI professor of Earth system science and NASA JPL research scientist.
New Ice Discovery Means Glaciers Could Melt Way Faster Than Predicted
Science Alert online
2023-05-10
A closer look at the junction where a Greenland glacier crunches into the ocean floor, known as its grounding line, has revealed less stability amid the shifting of tides – and therefore a greater rate of melting – than previously estimated thanks to global warming. The finding explains why rates of glacier melts are well surpassing previous forecasts. "These dynamics are not included in models, and if we were to include them, it would increase projections of sea level rise by up to 200 percent – not just for Petermann but for all glaciers ending in the ocean, which is most of northern Greenland and all of Antarctica," says Eric Rignot, an Earth systems scientist from the University of California, Irvine (UCI). … UCI glaciologist Enrico Ciracì and colleagues analyzed the satellite data for Petermann Glacier's grounding zone in Northwest Greenland.
Sea level rise could be double what scientists previously expected
KNX News radio
2023-05-10
In a recently published study, scientists have discovered a new way that the ocean and ice interact, all but resetting estimates of how high they expect sea levels to rise as a result of climate change and melting polar ice. The study comes from a group of researchers from the University of California, Irvine and NASA’s Jet Propulsion Laboratory. … Eric Rignot, a UCI professor of Earth system science and NASA JPL research scientist, shared in the study that their findings show glaciers are far more sensitive to the warming oceans than previously thought. Even more concerning is how Rignot says this will affect projections concerning the rising sea level.
Greenland glacier discovery shows sea level projections are too low
Axios online
2023-05-09
Scientists may be significantly underestimating the amount of melting yet to come from glaciers that end in the sea, according to a new study. Why it matters: The study reveals that seawater is intruding deep into northwest Greenland's Petermann Glacier, thinning the ice from below. Most computer models used to project ice melt from marine-terminating glaciers like Petermann assume that little to no melting occurs at the grounding line, study coauthor Eric Rignot of NASA's Jet Propulsion Laboratory and [professor of Earth system science at] University of California, Irvine told Axios via email.
Warming Ocean Tides Melt Glaciers, Which Makes Sea Levels Rise, Which Melts More Glaciers
Gizmodo online
2023-05-09
In a new study … researchers at NASA and the University of California Irvine explained that the Petermann Glacier’s interactions with increasingly warming ocean tides are causing that glacier to retreat faster than previously observed. … “These ice-ocean interactions make the glaciers more sensitive to ocean warming,” Eric Rignot, [UCI professor of Earth system science and] a NASA Jet Propulsion Lab research scientist, said in a statement. “These dynamics are not included in models, and if we were to include them, it would increase projections of sea level rise by up to 200 per cent – not just for Petermann but for all glaciers ending in the ocean, which is most of northern Greenland and all of Antarctica.”
Greenland glacier melting faster than previously thought: Here's what that means for future sea-level rise
Fox Weather tv
2023-05-10
Researchers studying a glacier in remote northwestern Greenland said they found that it’s melting faster than previously thought, which could mean that the climate community has been underestimating the magnitude of future sea-level rise. … According to the study, when the grounding line retreated by about 2.3 miles between 2016 and 2022, it carved a cavity nearly 670 feet high – taller than The Gateway Arch in St. Louis. "The glacier has not recovered from that retreat, and the ocean waters keep enlarging the size of that cavity," study co-author and University of California, Irvine, (UCI) professor of Earth system science and NASA Jet Propulsion Laboratory research scientist Eric Rignot told FOX Weather. "The water is regularly flushed in and out of the cavity by the ocean tides, which makes the matter worse."
Sea Level Rise Could Be Double Previous Estimates, NASA/UCI Study Finds
Science Blog online
2023-05-08
A group of researchers from the University of California, Irvine and NASA’s Jet Propulsion Laboratory have uncovered a surprising new way in which ice and the ocean interact. They have been studying the Petermann Glacier in northwest Greenland …. The researchers said their discovery means that the climate community has been underestimating the magnitude of future sea level rise caused by polar ice deterioration. … These ice-ocean interactions make the glaciers more sensitive to ocean warming, according to senior co-author Eric Rignot, UCI professor of Earth system science and NASA JPL research scientist. … Enrico Ciraci, UCI assistant specialist in Earth system science and NASA postdoctoral fellow, said that their findings could help improve models and projections for future sea level rise.
A major Greenland glacier is melting away with the tide, which could signal faster sea level rise, study finds
CNN online
2023-05-08
A major glacier in northwest Greenland is interacting with the ocean tides, scientists reported Monday, resulting in previously unaccounted-for melting and potentially faster sea level rise. The group of glaciologists from the University of California, Irvine and NASA’s Jet Propulsion Laboratory published the study in the Proceedings of the National Academy of Sciences on Monday. … Petermann’s grounding line “migrates between 2 and 6 kilometers (1.2 to 3.7 miles) as tides come in and out,” according to Enrico Ciracì, [assistant specialist], the lead author of the study and a scientist at UCI. This is an important finding: The traditional view among scientists was that the grounding line did not migrate with the tides – and this introduces another major source of melting that could be accelerating sea level rise. … “These ice-ocean interactions make the glaciers more sensitive to ocean warming,” said co-author Eric Rignot, a professor at UCI ….
Warming-stoked tides eating huge holes in Greenland glacier
Associated Press online
2023-05-08
Daily tides stoked with increasingly warmer water ate a hole taller than the Washington Monument at the bottom of one of Greenland’s major glaciers in the last couple years, accelerating the retreat of a crucial part of the glacier, a new study found. And scientists worry that the phenomenon isn’t limited to this one glacier, raising questions about previous projections of melting rates on the world’s vulnerable ice sheets. … “It’s bad news,” said study author [Professor] Eric Rignot, a glaciologist at University of California Irvine. “We know the current projections are too conservative. We know that they have a really hard time matching the current record″ of melt. He said this newly found consequence of tidal activity “could potentially double the projections” of global melt.
A Greenland glacier’s rapid melting may signal faster sea level rise
The Washington Post online
2023-05-08
Scientists studying one of Greenland’s largest glaciers say it is melting far faster than expected in its most vulnerable region, a worrying sign that glaciers perched in the ocean could contribute to sea level rise more quickly than currently forecast. … “You have this constant flushing of seawater going many kilometers below the glacier and melting the ice,” said [Professor] Eric Rignot, one of the study’s authors and a glaciologist at the University of California, Irvine and the Jet Propulsion Laboratory at the California Institute of Technology. “We think that could change sea level projections quite a bit,” he said.
Redefining “Glacial Pace”
EOS online
2023-04-24
Altimetry comes from the Ice, Cloud, and land Elevation Satellite-2 (ICESat-2), which uses a laser to measure changes in elevation across all of Earth’s surface, with an emphasis on the ice sheets, where changes reveal how the ice is thinning. “For the glaciers in Greenland, altimetry shows that they can thin by as much as 10 to 20 meters a year,” said Eric Rignot, a professor of Earth system science at the University of California, Irvine. “In Antarctica, especially West Antarctica, the thinning is about 10 meters per year.” … “Ice retreat is already pretty fast, but if we can get a better handle on the climate, we can slow it down,” said Rignot. “While retreat is inevitable, the speed can be controlled. That’s the important point.”
Disturbing Sea Level Studies
Counter Punch online
2023-04-14
As reported by Inside Climate News, the [Christine] Batchelor study has alarmed climate scientists, especially glaciologists at the top of the field like Eric Rignot … According to Eric Rignot, [professor of Earth system science], glaciologist at the University of California, Irvine and Caltech’s Jet Propulsion Laboratory: “This is an important study revealing that we have not seen anything yet in terms of how fast an ice sheet can retreat dynamically, not just melting away, but falling apart… This is not a model. This is real data. And it is frankly scary, even to me. These data should keep us awake at night.”
Ice age data raises new concerns about future ice melt, rising sea levels
UPI online
2023-04-06
"Ice sheets are retreating fast today, especially in Antarctica," said Eric Rignot, [professor of Earth system science] at the University of California at Irvine who was not involved in the study. "But we see traces in the seafloor that the retreat could go faster, way faster, and this is a reminder that we have not seen everything yet."
Global Warming Could Drive Pulses of Ice Sheet Retreat Reaching 2,000 Feet Per Day
Inside Climate News online
2023-04-05
The findings highlight the importance of stopping the current course of ice sheet melting driven by human impacts to the climate, said Eric Rignot, [professor of Earth system science], a glaciologist at the University of California, Irvine and Caltech’s Jet Propulsion Laboratory, who was not involved in the new research but has measured accelerating ice sheet retreat around Antarctica with his own research. “This is an important study revealing that we have not seen anything yet in terms of how fast an ice sheet can retreat dynamically, not just melting away, but falling apart,” he said.
‘Scary’ new data on the last ice age raises concerns about future sea levels
The Washington Post online
2023-04-05
“This is not a model. This is real observation. And it is frankly scary. Even to me,” Eric Rignot, a glaciologist …. In the past, one of the fastest retreat rates detected for a glacier was at Pope Glacier in West Antarctica …. The rate of retreat at Pope has now slowed down …. Still, it’s worrying, said Rignot, one of the scientists who published a 2022 paper that documented Pope glacier’s retreat. “Ice sheets are retreating fast today, [especially] in Antarctica,” Rignot, a [professor of Earth system science] at the University of California, Irvine. “But we see traces in the seafloor that the retreat could go faster, way faster, and this is a reminder that we have not seen everything yet.”
Warming seas are carving into massive Antarctic glacier that could trigger sea level rise
The Washington Post online
2023-02-15
Thwaites [Glacier] has been losing ice at an accelerating pace, based on data provided by Eric Rignot, one of the studies’ co-authors [and a professor], at the University of California, Irvine. The rate of loss overall since 1979 has been a little less than 20 billion tons per year, but that has increased to more than 40 billion tons since 2010, according to the data Rignot provided. “This robot is getting to the hard places where we need to go to understand the future of the continent," Rignot said. "We cannot understand what we cannot observe and measure.”
Skinny robot documents forces eroding Doomsday Glacier
Associated Press online
2023-02-15
The key to seeing exactly how bad conditions are on the glacier would require going to the main trunk and looking at the melting from below. But that would require a helicopter to land on the ice instead of a heavier airplane and would be incredibly difficult, said studies co-author [and professor] Eric Rignot of the University of California, Irvine. The main trunk’s glacier surface “is so messed up by crevasses it looks like a set of sugar cubes almost. There’s no place to land a plane,” NSF’s [Paul] Cutler said.
How a seal and a robot helped uncover a potential climate change disaster
The Washington Post online
2023-01-20
A striking discovery came in 2019. Using satellite data and other techniques, scientists published a new elevation map of all the crushed-down land beneath the Antarctic ice sheet. … “We dug out these data because we wanted to find out if warm water can indeed reach this glacier,” said Eric Rignot, [Earth system science Chancellor's Professor], an Antarctic expert at the University of California, Irvine and one of the authors of the paper. “The answer seemed to be yes.”
Tech Tuesday: Trump's social media platform faltering
WOSU online
2022-09-13
Guests: Eric J Rignot, Glaciologist at UC Irvine and Caltech's Jet Propulsion Laboratory Drew Harwell, Technology Reporter, Washington Post Russell Holly, Managing Editor for Commerce at CNET
What would the Earth look like if all the ice melted? The answer is terrifying.
Upworthy online
2022-04-26
And yet, the extent of this effect—along with its implications for rising sea levels—is still being discounted by the global scientific community. "It's like cutting the feet off the glacier rather than melting the whole body," Eric Rignot, a study co-author and a glacier researcher at NASA's Jet Propulsion Laboratory and the University of California at Irvine, told The Washington Post. "You melt the feet and the body falls down, as opposed to melting the whole body. I think this is an example that the current projections are conservative. As we peer below we realize these feedbacks are kicking in faster than we thought."
April 21, 2022 | A Conversation for Our Future
The Nature Conservancy online
2022-03-23
Dr. Eric Rignot is a Chancellor Professor of Earth system science at the University of California, Irvine, and Senior Research Scientist for the Radar Science and Engineering Section at NASA's Jet Propulsion Laboratory. He is a principal investigator on several NASA-funded projects to study the mass balance of the Greenland ice sheets and Antarctic ice sheets by using radar interferometry and other methods. In 2007 he contributed to the IPCC Fourth Assessment Report WGI (Working Group I) which was awarded the Nobel Peace Prize along with VP Al Gore.
UCI, NASA JPL Researchers Detail Causes of Glacier Retreat in West Antarctica
Environmental News Network online
2022-03-11
“Alpine glaciers retreat by about 1 kilometer per century, so it’s alarming to see these Antarctic glaciers receding at as much as 12 times that rate per year,” said co-author Eric Rignot, UCI Donald Bren Professor and Chancellor’s Professor of Earth system science and NASA JPL senior research scientist. “This pace is at the upper limit of what our models can replicate.”
NASA Greenland Mission Completes Six Years of Mapping Unknown Terrain
National Aeronautics and Space Administration online
2022-01-26
The mission’s first job was to map the seafloor around the island to see where deep, warm water can reach glaciers. A contractor completed most of the mapping using a research boat, and OMG Deputy Principal Investigator Eric Rignot of JPL and the University of California, Irvine led smaller surveys in following years to fill in missing sections.
New research on arctic ice shelves’ ‘icy glue’ shows they may melt faster than expected
KTLA 5 tv
2021-10-14
A substance called mélange — made up of windblown snow, iceberg bits, and sea ice — is lodged in and around arctic ice shelves and critical to holding them together, which may make the glaciers melt even faster than previously expected amid rising temperatures, according to a study at UC Irvine and NASA’s Jet Propulsion Laboratory in Pasadena. The same process may have caused an iceberg the size of Delaware to break off Antarctica in 2017, the researchers say.
Icy ‘Glue’ May Control Pace of Antarctic Ice-Shelf Breakup
International Business Times online
2021-10-12
To answer that question, the JPL and UC Irvine researchers focused on mélange. This messy, chunky mixture has natural properties similar to glue or grout, filling cracks or gaps and sticking to ice and rock. When it accumulates in a crack in an ice shelf, it creates a thin layer as hard as the surrounding ice that holds the crack together. At the sides of ice shelves, layers of mélange glue the ice to the rock walls around it. “We always suspected that this mélange played a key role, but until recently we did not have good observations of its characteristics,” said Eric Rignot, a professor at UC Irvine and co-author of the study, published in the Proceedings of the National Academy of Sciences.
Articles (3)
Ice flow modelling to constrain the surface mass balance and ice discharge of San Rafael Glacier, Northern Patagonia Icefield
Journal of GlaciologyGabriella Collao-Barrios, Fabien Gillet-Chaulet, Vincent Favier, Gino Casassa Etienne Berthier, Ines Dussaillant, Jeremie Mouginot, Eric Rignot
2018 We simulate the ice dynamics of the San Rafael Glacier (SRG) in the Northern Patagonia Icefield (46.7°S, 73.5°W), using glacier geometry obtained by airborne gravity measurements. The full-Stokes ice flow model (Elmer/Ice) is initialized using an inverse method to infer the basal friction coefficient from a satellite-derived surface velocity mosaic. The high surface velocities (7.6 km a ⁻¹ ) near the glacier front are explained by low basal shear stresses (1 km a ⁻¹ ). We force the model using different surface mass-balance scenarios taken or adapted from previous studies and geodetic elevation changes between 2000 and 2012. Our results suggest that previous estimates of average surface mass balance over the entire glacier ( Ḃ ) were likely too high, mainly due to an overestimation in the accumulation area. We propose that most of SRG imbalance is due to the large ice discharge (−0.83 ± 0.08 Gt a ⁻¹ ) and a slightly positive Ḃ (0.08 ± 0.06 Gt a ⁻¹ ). The committed mass-loss estimate over the next century is −0.34 ± 0.03 Gt a ⁻¹ . This study demonstrates that surface mass-balance estimates and glacier wastage projections can be improved using a physically based ice flow model.
Mass balance of the Antarctic Ice Sheet from 1992 to 2017
NatureAndrew Shepherd, Erik R. Ivins, Eric Rignot, Bert Wouters et al.
2018 The Antarctic Ice Sheet is an important indicator of climate change and driver of sea-level rise. Here we combine satellite observations of its changing volume, flow and gravitational attraction with modelling of its surface mass balance to show that it lost 2,720 ± 1,390 billion tonnes of ice between 1992 and 2017, which corresponds to an increase in mean sea level of 7.6 ± 3.9 millimetres (errors are one standard deviation). Over this period, ocean-driven melting has caused rates of ice loss from West Antarctica to increase from 53 ± 29 billion to 159 ± 26 billion tonnes per year; ice-shelf collapse has increased the rate of ice loss from the Antarctic Peninsula from 7 ± 13 billion to 33 ± 16 billion tonnes per year. We find large variations in and among model estimates of surface mass balance and glacial isostatic adjustment for East Antarctica, with its average rate of mass gain over the period 1992–2017 (5 ± 46 billion tonnes per year) being the least certain.
Intercomparison and Validation of SAR-Based Ice Velocity Measurement Techniques within the Greenland Ice Sheet CCI Project
Remote SensingJohn Peter Merryman Boncori, Morten Langer Andersen, Jørgen Dall, Anders Kusk, Eric Rignot et al.
2018 Ice velocity is one of the products associated with the Ice Sheets Essential Climate Variable. This paper describes the intercomparison and validation of ice-velocity measurements carried out by several international research groups within the European Space Agency Greenland Ice Sheet Climate Change Initiative project, based on space-borne Synthetic Aperture Radar (SAR) data. The goal of this activity was to survey the best SAR-based measurement and error characterization approaches currently in practice. To this end, four experiments were carried out, related to different processing techniques and scenarios, namely differential SAR interferometry, multi aperture SAR interferometry and offset-tracking of incoherent as well as of partially-coherent data. For each task, participants were provided with common datasets covering areas located on the Greenland ice-sheet margin and asked to provide mean velocity maps, quality characterization and a description of processing algorithms and parameters. The results were then intercompared and validated against GPS data, revealing in several cases significant differences in terms of coverage and accuracy. The algorithmic steps and parameters influencing the coverage, accuracy and spatial resolution of the measurements are discussed in detail for each technique, as well as the consistency between quality parameters and validation results. This allows several recommendations to be formulated, in particular concerning procedures which can reduce the impact of analyst decisions, and which are often found to be the cause of sub-optimal algorithm performance.
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