Glaciologists unveil most precise map ever of Antarctic ice velocity

From the AGU

Project utilized 25 years of data from six international satellite missions

29 July 2019

Joint Release

WASHINGTON — Constructed from a quarter century’s worth of satellite data, a new map of Antarctic ice velocity by glaciologists from the University of California, Irvine and NASA’s Jet Propulsion Laboratory is the most precise ever created.

Published today in a new paper in the AGU journal Geophysical Research Letters, the map is 10 times more accurate than previous renditions, covering more than 80 percent of the continent.

“By utilizing the full potential of interferometric phase signals from satellite synthetic-aperture radars, we have achieved a quantum leap in the description of ice flow in Antarctica,” said lead author Jeremie Mouginot, UCI associate researcher in Earth system science. “This more detailed representation will help improve our understanding of ice behavior under climate stress over a larger part of the continent, farther south, and will enable improved projections of sea level rise through numerical models.”

A new map of Antarctic ice velocity constructed from nearly a quarter century’s worth of satellite data. Credit: AGU

A new map of Antarctic ice velocity constructed from nearly a quarter century’s worth of satellite data. Credit: AGU

To chart the movement of ice sheets across the surface of the enormous land mass, the researchers combined input from six satellite missions: the Canadian Space Agency’s Radarsat-1 and Radarsat-2; the European Space Agency’s Earth remote sensing satellites 1 and 2 and Envisat ASAR; and the Japan Aerospace Exploration Agency’s ALOS PALSAR-1.

While the data were spread across 25 years, the pace of signal gathering accelerated in the last decade as more resources were deployed in the Earth’s orbit. As ice sheet science coordinator in the World Meteorological Organization’s Polar Space Task Group, co-author Bernd Scheuchl, UCI associate project scientist in Earth system science, was responsible for acquiring the relevant data from the various international space agencies.

Previous mapping efforts relied heavily on “feature” and “speckle tracking” methods, which detect the subtle motion of parcels of ice on the ground over time; this approach has been proven effective in estimating ice flow speed. To measure significantly slower ice sheet movement in the vast interior regions, the UCI team augmented these techniques with synthetic-aperture radar phase interferometry, which detects the subtle motion of natural reflectors of radar signals in snow/ice independent of the size of the parcel of ice illuminated by the radar.

“The interferometric phase of SAR data measures the ice deformation signal with a precision of up to two orders of magnitude better than speckle tracking,” Mouginot said. “A drawback is that it requires a lot more data, namely multiple passes at different angles over the same point on the ground – a problem that was solved by a consortium of international space agencies pointing Earth-monitoring spacecrafts to this part of the world.”

The team was able to compose a map that resolves ice movement to a level of 20 centimeters (a little over half a foot) per year in speed and 5 degrees in annual flow direction for more than 70 percent of Antarctica. It’s the first time that high-precision mapping of the interior areas has been accomplished.

“This product will help climate scientists achieve a number of goals, such as a better determination of the boundaries between glaciers and a thorough evaluation of regional atmospheric climate models over the entire continent,” said co-author Eric Rignot, chair and Donald Bren Professor of Earth System Science at UCI and a JPL senior research scientist.

“It will also help in locating the most promising sites for ice core drilling to extract climate records and in examining the mass balance of Antarctica beyond its periphery.”

Full article here.

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55 thoughts on “Glaciologists unveil most precise map ever of Antarctic ice velocity

  1. The article mentions benefits to people called “climate scientists”.
    Is that a proper job?

    • They all need to rounded-up and shipped en mass to East Antarctica for year long tour to learn about Global Warming and “polar amplification” that only appears to be working on one pole. Funny that.

    • ad hominem argument, eh? is that what is done on this site when an article is straight science?
      poor form

    • “climate scientologists” may be a more accurate moniker for their club. Indeed, the first rule of climate scientology club is not to speak ill of climate scientology club.

  2. Nice chart,
    Is that a 2 axis or 3 axis map, signal collecting from elevations above a certain angle may fail due to total change in the surface material due to avalanche type changes/movements .
    Next step is to obtain finer resolution in the `time` axis as we know that things speed up and slow down on an irregular basis in terms of glaciers

    • Avalanching is very minor in Antarctica outside the northern part of the Antarctic peninsula.

      Too flat terrain mostly, too little precipitation, temperature akmost constantly below freezing, so no surface melting to provide slip surfaces.

    • That was my thinking too, jono1066. It’s the change in flow rate that they need to use when trying to scare us.

      • The flow rate is meaningless if the mass of ice isn’t changing, you can just be depositing more snow. This is just another piece of information of a complete science story that needs to be understood. The problem will be it will take probably a hundred years or more of data to actually be even able to work out what the variations are.

  3. Amalgamating 25 years of data to produce one map is only going to work if the situation is stable. If the climate is changing, for any reason, then there will be serious mismatches between the 25 year old data and the recent data.

    • Don’t worry, any anomalies will be made to conform/fit with the projects long term message….

    • Glacial ice flows downslope… always has always will, even when it retreats due to melting/ablation.

      • That’s right, David, and this presentation of ice mass accumulating in the interior, putting pressure on the ice to be ductile and flow, and it actually flows to the sea, is a wonderful presentation of Antarctica in perfect harmony and balance. Nothing to see here folks, move on!

    • Glaciers react slowly, large glacier react very slowly.

      There may be some change in the fastest moving ice-streams, but not in most of the continent.

      • Yep. Ice can only accumulate to a certain thickness. It flows downslope from the domes, eventually reaching higher velocity outlet glaciers, which flow to the sea.

        The “funny” thing is that the highest accumulation rate dome sits right next door to one of the highest velocity outlet glaciers…

        • David, thanks for all your inputs. They make these comment sections so much more valuable.

          We have an article about Antarctic glaciers and you give us a detailed look, in your comment. That’s what I love about this place! Lots of detailed looks from a lot of intelligent, resourceful people. 🙂

  4. The team was able to compose a map that resolves ice movement to a level of 20 centimeters (a little over half a foot) per year in speed … so basically everything that is green or brown is below the threshold of measurement. And the only bits where there is meaningful data is where it is blue or red.

  5. Does anyone know, what the stated/written objectives of this highly integrated research project actually is?

    • a CYA for the extra megamillions spent by Aussies on extra Antarctic “research”, that would be better used at home on some new dams for droughted areas in future etc.

  6. I worry when I see the phrase ‘quantum leap’ inserted into the middle of all the technical jargon. It makes me wonder how accurate the rest of it is.

  7. “Project utilized 25 years of data from six international satellite missions”

    So complete BS then?!

  8. Looking at the map, mostly the only thing that is moving are ice sheets, i. e. the semi-floating shelves. Otherwise, bupkis as far as moving.

  9. It’s not a map of velocity. Velocity is a vector. All I see is an indication of speed, which is a scalar.

    It kind of looks like a series of rivers flowing down to the sea, rather than sheets sliding slowly southward northward.

  10. As is usual in climate/government work these days, the Press Release has terminological inexactitude with “accurate” and “precise”. I look forward to proper scientific use when I read the paper. The hope is for sentences like “Where the velocity is between 3 and 10 metres per year, the measurement accuracy is better than 0.05 metres per year, with 2 sigma uncertainty of +/- 0.005 metres per year” whatever the numbers are, written in the proper symbol manner.
    On the whole, if the numbers are indeed accurate enough for some envisaged purposes, the end result is a rather nice achievement, showing how useful satellites can be when combined with knowledge of various forms of radar and laser responses over ice. I am impressed. Geoff S

  11. That ice-velocity colour-stretch is terrible. A geologist (me) recommends, from slowest: blue-green-yellow-orange-red-magenta…and white if needed for the highest.

    • Half of the heat maps in climate science can’t even do them in normal physics colours and you expect them to do it right for flow rates 🙂

      • On graphs, I just wish they would have a convention as to which way they read as far as to date, with either newer to the right or left, just so long as it was consistent.

  12. This here new interferometric clearly shows the ice movement speed is worse that we thought compared to the start of the Industrial Revolution so the message is clear. Deindustrialize of die. Quick get Monbiot on the blower.

  13. Speaking of ‘Rebel for Life’ George and the ‘Rabbits unite against fracking’ at the 1:35 mark George finally seems to get it- “33 years I have waited and 33 years it has not happened!”[make that 34 because he was rabbiting on last year] Well far be it from me to quote the perpetual struggle manual chapter and verse to you George old boy but don’t you simply push the dooming out the usual 12 years again?

  14. But why bother? I thought the world was going to end in 12 years… or 11 years… or 10 years. Whatever. The countdown has begun already. These glaciers have already melted and we are all drowning already. Doomed I say. Doomed.

  15. Velocity, of ice or anything else, is a vector quantity, with a magnitude (speed) and direction. The map in the article indicates the speed only, but not the direction of movement. It would be helpful if the “velocity” map included arrows indicating the direction of movement–is it radially outward from the South Pole or other center, or are there some tangential (east/west) components?

    If there are order-of-magnitude spatial differences in velocity, there should be areas where ice is either accumulating or being depleted, neither of which are shown by the map in the article.

  16. These clowns need to get a heat gun and fire it at the surface of the water and note the result.

  17. Why is it I don’t see any influence from the underwater volcanoes in Western Antarctica?

  18. This is an interesting map for what it doesn’t show. One frequently hears concerns expressed about the potential for surge in the glaciers (and subsequent rapid increase in sea level) if the pack ice or grounded terminuses (termini?) were removed. That is, if something is buttressing the glaciers where they enter the ocean, wouldn’t one expect that the glacier would slow down at that point? Or, alternatively, at least maintain a constant speed? However, what is shown is the glaciers speeding up near the water. That is what I would expect to see if the primary impediment to forward motion was friction with the bedrock and ice near the terminus is experiencing buoyancy or entirely floating. In any event, it appears that the ice speeds up.

    However, even that raises questions. If the down-slope ice is speeding up, I would expect thinning to occur, or significant crevasses forming, in the zone where the speed increases and tension develops. Is that what is happening?

    In summary, this new report doesn’t seem to support the narrative about concerns over sudden changes in sea level.

    • No data ever seem “to support the narrative about concerns over sudden changes in sea level”… But it just hangs in there like a zombie… 😉

      • OK, I’ll bite. The sea gates at both Harlech castle (seen for myself) and Caernarfon castle (reportedly)
        are both at least 3m above present sea level at high tide. Snowdonia is geologically stable over the last 1000 years so why? West antartic ice shelf is the only candidate for this sort of sea level rise, is unstable, and has volcanoes under it. Discuss.

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