First ICESat-2 Global Data Released: Ice, Forests and More

From NASA Global Climate Change

To assess the accuracy of the newly released ICESat-2 data, a NASA team set out to the South Pole. For the second-straight year, the team endured below-freezing temperatures, biting winds, and high altitude to conduct a traverse along the 88 degree south latitude line, taking highly accurate GPS measurements to compare with those from the satellite. Credit: NASA Goddard/Kelly Brunt

To assess the accuracy of the newly released ICESat-2 data, a NASA team set out to the South Pole. For the second-straight year, the team endured below-freezing temperatures, biting winds, and high altitude to conduct a traverse along the 88 degree south latitude line, taking highly accurate GPS measurements to compare with those from the satellite. Credit: NASA Goddard/Kelly Brunt

By Kate Ramsayer,
NASA’s Goddard Space Flight Center

More than a trillion new measurements of Earth’s height – blanketing everything from glaciers in Greenland, to mangrove forests in Florida, to sea ice surrounding Antarctica – are now available to the public. With millions more observations added each day, data from NASA’s Ice, Cloud and land Elevation Satellite-2 is providing a precise global portrait of elevation and will allow scientists to track even the slightest changes in the planet’s polar regions.

“The data from ICESat-2 are really blowing our minds, and I’m really excited to see what people with different perspectives will do with it,” said Lori Magruder, a senior research scientist at the University of Texas, Austin, and the ICESat-2 science team lead.

The long-awaited ICESat-2 mission, launched in September 2018, continues the record of polar height data begun with the first ICESat satellite, which operated from 2003 to 2009. NASA’s airborne Operation IceBridge project bridged the data gap between the two satellites. The new satellite provides far more measurements than its predecessor. ICESat took approximately 2 billion measurements in its lifetime, a figure ICESat-2 surpassed within its first week.

For the second straight year, NASA researchers endured low temperatures, biting winds, and high altitude to conduct another 88-South Traverse. The 470-mile expedition in one of the most barren landscapes on Earth provides the best means of assessment of the accuracy of data collected from space by the Ice Cloud and land Elevation Satellite-2 (ICESat-2). Credit: NASA’s Goddard Space Flight Center/Ryan Fitzgibbons. This video is available for download at NASA’s Scientific Visualization Studio.

When ICESat orbited over a rift in Antarctica’s Filchner-Ronne Ice Shelf in October 2008, for example, it recorded a handful of data points indicating a crevasse in the ice. When ICESat-2 passed over 10 years later, it collected hundreds of measurements tracing the sheer walls and jagged floor of the growing rift.

ICESat-2 is taking these measurements in a dense grid across the Arctic as well as Antarctica, recording each spot every season to track both seasonal and annual changes in ice.

ICESat-2’s ability to measure heights beyond the poles is also impressing scientists – Magruder pointed to coastal areas, where in clear waters the satellite can detect the seafloor up to 100 feet (30 m) below the surface. Over forests, the satellite not only detects the top of the canopy, but the forest floor below – which will allow researchers to calculate the mass of vegetation in a given area.

All this is being done with six laser beams from a satellite 310 miles (500 kilometers) in space, noted Tom Neumann, ICESat-2 project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

“Getting the exact latitude, longitude, and elevation of where a photon bounced off Earth is hard – lots of things have to happen and go really, really well,” he said. To make sure everything is working, the science team conducts a series of checks using data from airborne surveys, ground-based campaigns, even the satellite itself.

That includes scientists travelling to Antarctica, where they drove modified snow-groomers along an arc of the 88-degree-south latitude line, taking highly accurate elevation measurements to compare with the data collected by ICESat-2 in space. Magruder compared measurements taken in White Sands, New Mexico, with what the satellite was tracking. In its most recent Antarctic and Arctic campaigns, NASA’s airborne Operation IceBridge flew specific routes designed to take measurements over the same ice, at close to or exactly the same time the satellite flew overhead.

ICESat-2 is designed to precisely measure the height of ice and track how it changes over time. Earth’s melting glaciers cause sea levels to rise globally, and shrinking sea ice can change weather and climate patterns far from the planet’s poles.

Small changes across vast areas like the Greenland ice sheet can have large consequences. ICESat-2 will be able to measure the shift in annual elevation across the ice sheet to within a fraction of an inch. To do this, the satellite uses a laser altimeter – an instrument that times how long it takes light to travel to Earth’s surface and back. With that time – along with the knowledge of where in space ICESat-2 is, and where on Earth the laser is pointing – computer programs create a height data point. The data is originally processed at NASA Goddard, then turned into advanced data products that researchers will be able to use to study elevations across the globe.

ICESat-2 data products are now available for free from the National Snow and Ice Data Center at https://nsidc.org/data/icesat-2.

For more information, visit www.nasa.gov/content/goddard/icesat-2 or https://icesat-2.gsfc.nasa.gov/. For more information on the data products, visit https://earthdata.nasa.gov/icesat-2-data.

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60 thoughts on “First ICESat-2 Global Data Released: Ice, Forests and More

  1. Bravo – that is what we really need : Data, Date, Data. Trillions of exact observations, year after year. Then, perhaps after only a few years we can see clearly and unambiguously what is happening – and react if possible (and necessary).

    • I was thinking along those lines as well, then I reached the part of the last complete paragraph where it states; ” The data is originally processed at NASA Goddard, then turned into advanced data products”.

      I seem to recall data being processed by NASA on previous occasions. Will anyone outside NASA have access to the raw data in a usable form? Will NASA inform us of the processing protocols and algorithms they inflict on the data before it is released? Until we know the whole truth we will not be able to assess the real value of all this data .

      • I am also concerned that NASA will “process” the data until they get the answer they want.

        Or at least suppress the the parts of the data that do not give the answer they want, as they have with OCO-2.

        • In all probability you are correct, particularly if the facts don’t support the narrative.

        • Agreed: they already know what they want to show… “Earth’s melting glaciers cause sea levels to rise globally, …”

    • With lots and lots of accurate data like this, people such as Michael Mann and Al Gore will know precisely where they are (for a change).

  2. So the satellite guys measuring (essentially) fixed ice height on Antartica are hoping for accuracy in the centimeter range while the satellite sea level guys think they can measure variable sea level height to an accuracy of fractions of a millimeter. Seems like they should to talk to one another. Or not.

    • Strangely, noise can improve accuracy. link If waves can be treated as gaussian noise then it might be possible to measure sea level more accurately than land elevation.

      The big problem, which I think too many scientists aren’t even aware of, is that nature tends not to produce gaussian noise. Nature tends to produce red noise where lower frequencies predominate. When you try averaging on data with red noise content, your accuracy gets much worse.

      • When measuring sea levels you are also measuring land levels as well. After all, the sea rests on terra firma. Or is there some reason the seabed cannot vary in height?

        • Col Mosby, are you suggesting that a local rise in the sea bed will cause a rise in sea level above it? That makes as much sense as dredging the channel below a bridge so that taller ships can pass under the bridge.
          Of course the sea bed varies in height, from miles at deep trenches to zero at the shoreline.
          Shoreline gauges measure the relative difference between the land and the sea.
          Satellites measure relative difference between the satellite altitude and the sea surface. Since the satellite altitude is precisely determined by its velocity and Earth’s gravitational field, its radial distance from the center of the Earth is well known and knowable.
          Now that better land altitude measurements can be made relative to the center of the Earth a better calculation can be made between the two to determine which is rising and which is sinking.

          • Rocketscientist
            As I see it, the problem is that out in the middle of Greenland, and especially Antarctica, there is no one on the ground to measure the satellite velocity. Furthermore, the Earth’s gravity is not uniform and is modeled. As snow/ice levels change over the poles, gravity will change even if there is nothing happening in the crust or mantle below.

            ICESAT can do a good job of determining how thick floating ice is, but the absolute elevation of continental glaciers is more problematic.

          • I agree with Clyde in this respect. Mean sea level should be defined as the equipotential gravitational surface corresponding to the mean (over the entire sea) surface level. It sounds redundant, but is not. It is possible to measure (to many, many decimal places) gravitational potential at any given location. Pairing the MSL measurements of geologically stable tidal gauges will ultimately produce the eqipotential surface.

      • Strangely, noise can improve accuracy. link If waves can be treated as gaussian noise then it might be possible to measure sea level more accurately than land elevation.

        I suppose that you can treat waves any way you want. But the reality is that they are likely to be a bit ill-behaved most of the time because the wind can act on the peaks a lot more actively than it can on the troughs. That often results in rather odd shapes eventually ending up with breaking crests when the top is literally blown off the wave. Also, IIRC, the footprint of ICEsat’s laser is bigger than you might expect — tens of meters rather than the pinpoint we tend to associate with lasers. (Turns out to be 17m for ICEsat2) That’s a lot better than Jason’s several kilometers, but it still allows considerable differences in elevation within the footprint.

      • Although I don’t have the reference at hand, or care to try to find the web pages, in articles on satellite altimetry sea level measurements I have read that the NOAA data user’s manual states that the measurement accuracy is +/- 3.4cm for the older satellites, +/-3.3cm for the latest satellite. The partial millimeter accuracy comes from the magic of not paying any attention to significant digit limitations in rounding off intermediary results when making statistical calculations.

  3. If the raw ICESat2 data doesn’t conform to CAGW’s Antarctic/Greenland ice-mass narrative, I’m sure the grant hounds will “augment” the data with highly inaccurate GRACE satellite data to get the “results” they desire…

  4. “Small changes across vast areas like the Greenland ice sheet can have large consequences. ICESat-2 will be able to measure the shift in annual elevation across the ice sheet to within a fraction of an inch. ”

    Wonderful, then we only need to measure the density profile of the snow, to get useful data. We could use GRACE data for that, if only we could measure the altitude of the bedrock below the ice within a fraction of an inch….. it might not be so easy after all.

  5. OH, cotton-pickin’! For a brief moment, I thought that photo was a yurt in Mongolia being hootched along by yaks. You guys took all the romance out of my idea.

    • True story – I live near Toronto Canada. I worked with a young woman from Mongolia. As a child and adolescent she traveled with her family living in a yurt, following the herds. They stayed near a town when she was old enough, and she rode a horse into town to attend classes. Eventually the family emigrated to Canada where she became an accountant.

  6. Glaciers are complicated. They move. In Greenland, snow is added from above and water and ice are removed from below. In WW2, some aircraft landed on Greenland. Now they’re buried 300 feet below the surface of the glacier. link I’m pretty sure the top of the ice isn’t 300 feet higher than it was in WW2.

    In light of the above, it would be handy to mount some reflectors on top of the ice so they could track its movement. I’d mount them on ten foot poles so they wouldn’t get buried too quickly. 🙂

    • From time to time I look to see if I can find the altitude of Greenland’s Summit station over time. So far I haven’t found it. I’m guessing it doesn’t really change much which of course wouldn’t fit the narrative.

    • Quote:”In WW2, some aircraft landed on Greenland. Now they’re buried 300 feet below the surface of the glacier. link I’m pretty sure the top of the ice isn’t 300 feet higher than it was in WW2.”

      With more than 12 m of snow a year (SE-Greenland) and and taking inot account the compaction of firn the numbers should fit.
      Quote 2:
      “I’d mount them on ten foot poles so they wouldn’t get buried too quickly. 🙂”
      Wouldn’t take much more than a years snow fall.

      • It depends on logistics. The reflector would mark a location and wouldn’t have to be accurate for altitude. You could put in a ten foot pole and elevate it every six months. Depending on the location, you could mooch a trip with someone else.

        On the other hand, putting up a hundred foot tower is guaranteed to be a ‘big deal’. Everything in the arctic, except real estate, costs much more and takes much more time than it would down south.

  7. Double checking height/elevation/altitude with GPS is smart. It will get them within two or three meters anyway.

    • More expensive GPS’s will cut that horizontal error in half at least, but the elevation is always bad with GPS. Perhaps that’s why they state their vertical accuracy to with a fraction of an inch?

  8. “More than a trillion new measurements of Earth’s height”

    Don’t you just love claims for massive numbers of occurrences when they never define exactly what “a measurement” is?
    Is a measurement based upon a laser pulse? Is it a combination of pulse and light capture? Or are the light pulse and light capture separate counts?
    At what resolution is a measurement?
    Laser light may be a tight beam when emitted, it still spreads over distance. The the scattered reflected light is then captured by the satellite?
    NASA then claims improves accuracy to within centimeters. On ice, snow and water?

    “When ICESat-2 passed over 10 years later, it collected hundreds of measurements tracing the sheer walls and jagged floor of the growing rift.”

    This sounds suspiciously like they are really describing data packets

    “That includes scientists travelling to Antarctica, where they drove modified snow-groomers along an arc of the 88-degree-south latitude line, taking highly accurate elevation measurements to compare with the data collected by ICESat-2 in space. Magruder compared measurements taken in White Sands, New Mexico, with what the satellite was tracking. In its most recent Antarctic and Arctic campaigns, NASA’s airborne Operation IceBridge flew specific routes designed to take measurements over the same ice, at close to or exactly the same time the satellite flew overhead.

    ICESat-2 is designed to precisely measure the height of ice and track how it changes over time. Earth’s melting glaciers cause sea levels to rise globally, and shrinking sea ice can change weather and climate patterns far from the planet’s poles.”

    This sounds like another excuse for researchers to visit exotic locales.

    N.B. where the author starts to justify this ICESat-2 as somehow critical to weather, climate and sea level.
    Once again, NASA proves they allow activists to subvert extremely expensive technology in another lame attempt to justify their alarmist souls.

    “Earth’s melting glaciers cause sea levels to rise globally”,
    “shrinking sea ice can change weather and climate patterns far from the planet’s poles”;
    Thus implying that glaciers do not grow, and that sea ice does not return to near normal levels every winter.

    While utterly failing to describe their efforts to turn these mechanical measurements into actual weather impacts with explicit weather examples.

    “The data is originally processed at NASA Goddard, then turned into advanced data products”

    An entity well known for smearing adjacent data, infilling missing measurements and dubious assumptions on how exceptions are handled all while ignoring error bounds.

    The laser measurement is based upon and utterly dependent upon time. How do they handle refracted light? Or how multiply reflected light?

    Looks to me like another expensive poorly justified satellite and dependent analysis department spending massive amounts of funding, wasting valuable time while broadcasting their alarmist confirmation bias.

    I am reminded of the 1980s and 1990s when computer processors trumpeted their new processing speeds as all important and substantive equipment improvements. Bulletin Boards were full of advice on how to overclock the processors to achieve yet more speed.

    All while constraints upon computers were input and output choke points. So long as the entire processing cycle was processor based, the computer did improve with increased processor speeds; the moment drives or even memory needed to be accessed, computers slowed down, considerably.

    The author, Kate Ramsayer’s flying a “trillion new measurements” banner is all smoke and mirrors to distract people from reality.

  9. Nice work, if you can trust it. This looks like an excellent opportunity for NASA to “calibrate” their published data set again…with even greater “accuracy.” An instant red flag for this would be if the masters of The Adjustocene refuse to provide the raw data for outside processing and interpretation. Keep your powder dry.

  10. Time mark 1:28 are they really using paper records in 2019? I suppose the producers of the YouTube think that makes it look much more “sciencey” than it is.

    • Hmm I dont know. If they are collecting records OUTSIDE at 88S, I imagine the smart thing
      to do is to create a paper record. Imagine whipping out your Ipad at – cold as hell and finding
      out the device was not rated to work at sub freezing temperatures.

  11. On NASA’s ICE-2 website they indicate that one of the “data products” is Sea Level.

    If ICE-2 is sensitive to 1/8 of an inch or around 3 mms (interpreting their declared solid land resolution of “a fraction of an inch” favorably…they probably meant “less than an inch”). Six inches would be very useful by the way.

    Even if ocean surface variations (at low to medium spatial resolution) were white noise (it isn’t – long wavelengths are heavily weighted) I don’t think an accuracy of anywhere near 0.1 mm is possible via accuracy amplification from noise. Sounds like a waste of effort…unless the “sea” data enhances the land and ice accuracy somehow. I’m sure the satellite doesn’t care.

    • Its the old square root of N readings accuracy improvement game that statisticians like to play. So if you measure a 2 x 4 to be 8′ 0 3/8″ with a tape measure, and you look at the tape a thousand times, your accuracy is much better than half of 1/8″….Once you see the equation worked out by someone, you are convinced, but are kidding yourself.

      • The best part is when you whip out your tape measure and measure the 2×4 right there and then, and discover its out by 3/8″. The look on their face is priceless.

  12. “The data from ICESat-2 are really blowing our minds, and I’m really excited to see what people with different perspectives will do with it,” said Lori Magruder, a senior research scientist at the University of Texas, Austin, and the ICESat-2 science team lead.

    Unfortunately, originating in an academic environment & funded by goobermint grants, it will mostly be used for propaganda supporting the climate-scam industry.

  13. The elevation data from ICEsat-2 should prove very useful for monitoring magma movements that cause land lift or drop, especially in areas with little or no land based GPS monitoring capability.

  14. A Survey rated laser measurement is accurate -reflectorless- to 2 millimeters +-2 ppm tolerances @500 meters
    (land surveyor i am putting the stats out for the sokkia im-50 class total station)

    so tolerances for the sat. data should be that good, and its a laser that records the data POINT you -should- be able to load the data set for the shots into any GIS/photogrammetry program and have it generate an accurate topopgraphic representation of the area you downloaded.

    sat takes 10k shots a second (a relatively low amount compared to high end land surveying laser scanners, they do up to 26 thousand shots a second)

    all the shots should have the following coords
    gps position of the shot on the geoid in a las file which contains the:
    x y and z coords and if it can do this, the code classification – water, ice, tree, ground etc.

    something like this:
    804228.56, 3017189.44, 29.25, 9

    first number is the x coord (east)
    second number is the y coordinate (north)
    third number is the z coordinate (elevation)
    fourth number is the land classification code…9 is water
    gis land classification number list:
    2 is ground
    3 is low vegetation
    4 is medium vegetation
    5 if high
    6 is buildings
    9 is water
    etc
    there is no definitive classification for ice. but if the designers of the system used the default GIS codes settings, it would be somewhere between 64 and 255 which are user defined.

    • The coding at the bottom are LiDAR data values. LiDAR is laser survey from an overhead plane. I’ve compared their accuracy with ground survey for design. Hard surfaces like pavements are usually in error by about 30mm. Long grass about 150mm, and with tree coverage of any sort the ground are 300mm or more in error. And I’ve found places where the data jumps all over the place for no apparent reason +- 1m.

  15. The ICEsat-2 elevation data should also be valuable for finding remnants of the ‘lost cities’ hidden beneath South American jungle canopies or under less than 100 feet of water around the Mediterranean Sea!

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  17. ICES has a satellite in space now?
    I thought we whupped up and sent ’em packing into history?

  18. View the impressive publicity video, then roll it again while you imagine NIL use of fossil fuel, as far too many ignorant idealists are protesting for. I fear for the future of science globally so long as these nut cases are being heard. Geoff

  19. To do this, the satellite uses a laser altimeter – an instrument that times how long it takes light to travel to Earth’s surface and back.

    Light does not travel.
    Travelling implies time.
    Light is outside of time.
    Since it propagates at the “speed” of – um – light, a light photon does not experience any passing of time.

    Time is different at either end of a light wavetrain.
    The longer the wavetrain the bigger the difference.
    Time and distance are one – Einstein’s chief insight.

    • PBS SpaceTime on youtube did a series of four videos on just this trying to explain it to intelligent laymen. You’re right in what you state, but I can’t get my head around it at all.

  20. I loved the video, and applaud the courage of these scientists. Anyone who thinks Antarctica is a breeze should read Admiral Richard Byrd’s Alone. He was determined to spend an Antarctic winter alone at an ice station near the South Pole. Unfortunately, not long into the ordeal, his kerosene stove flue leaked carbon monoxide into his below ground shelter, nearly killing him. It’s an amazing read, and I highly recommend it (spoiler alert: he survived [to, uh, write the book]).

  21. Great post. My prediction has been confirmed. anytime any new science or device is featured the comments
    will follow the same pattern.

    1. Great we need more X
    2. I dont believe Y,
    3. blah, blah blah, Mike mann
    4. blah blah blah… adjustments
    5. blah blah… einstein
    6. I would have done it this way
    7.. blah blah blah, dont trust nasa
    8.. when I was kid

    • You would prefer if we all cheered and congratulated them? Perhaps they do deserve some.

      Now since you initiated this snark, I shall continue in kind…

      steven mosher’s comments will follow the same pattern.
      1. Snark
      2. You’re wrong
      3. You need to read it
      4. Maths error
      5. blah blah blah… Snark
      6. Anthony still hasn’t published his code.

  22. One slight sadness: they do not record any data for a track segment that only passes over open ocean. So this cannot be used as a cross-check against global sea level assessments. I was hoping that this information might be useful for tracking soil erosion, but from some of the comments the (true) vertical resolution might not be up to it, and the horizontal resolution is not that great. I am a little puzzled: knowing the distance between “ground” and satellite is only going to give you elevation if you know the satellite’s position to the same accuracy; does anyone know how good that is?

  23. Greeeeat. Gonna track teeny tiny changes. Sounds like the gnat’s ass of ice and snow covering measurements designed to do one thing: Frighten weak minded people.

    Look, we are in a warm climate optimum with the slightest of nudges up and down. Why the hell do we need to spend more money likely targeted to make that look like a bad thing?

  24. Steven,

    Are you a bit credulous? In engineering school we learned about this thing, called Calibration. Huge variables, just what is the altitude of the bird, just what is Earth’s gravity field, just what is the resolution of this laser? Might have some data about the latter, the two formers, not so much.

    NASA is claiming 2 cm resolution, but with no evident calibration, and their record from GRACE and the previous ICE-SAT, “Inquiring Minds Want To Know….”

    Takes 8 GPS satellites simultaneously to get resolution under an inch. Sure, no one at NASA would take any liberties with this, mining-hating MoFo’s that they are….

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