New Arctic Ice Measurement Satellite with “frickin’ lasers on [its] head”

Next month, NASA will launch into space the most advanced laser instrument of its kind, beginning a mission to measure – in unprecedented detail – changes in the heights of Earth’s polar ice.

NASA’s Ice, Cloud and land Elevation Satellite-2 (ICESat-2) will measure the average annual elevation change of land ice covering Greenland and Antarctica to within the width of a pencil, capturing 60,000 measurements every second.

“The new observational technologies of ICESat-2 – a top recommendation of the scientific community in NASA’s first Earth science decadal survey – will advance our knowledge of how the ice sheets of Greenland and Antarctica contribute to sea level rise,” said Michael Freilich, director of the Earth Science Division in NASA’s Science Mission Directorate.

ICESat-2 will extend and improve upon NASA’s 15-year record of monitoring the change in polar ice heights, which started in 2003 with the first ICESat mission and continued in 2009 with NASA’s Operation IceBridge, an airborne research campaign that kept track of the accelerating rate of change.

NASA’s Ice, Cloud and land Elevation Satellite-2 (ICESat-2) will measure height with a laser instrument that features components designed to provide precise data. Credits: NASA/Adriana Manrique Gutierrez

A Technological Leap

ICESat-2 represents a major technological leap in our ability to measure changes in ice height. Its Advanced Topographic Laser Altimeter System (ATLAS) measures height by timing how long it takes individual light photons to travel from the spacecraft to Earth and back.

“ATLAS required us to develop new technologies to get the measurements needed by scientists to advance the research,” said Doug McLennan, ICESat-2 project manager at NASA’s Goddard Space Flight Center. “That meant we had to engineer a satellite instrument that not only will collect incredibly precise data, but also will collect more than 250 times as many height measurements as its predecessor.”

ATLAS will fire 10,000 times each second, sending hundreds of trillions of photons to the ground in six beams of green light. The roundtrip of individual laser photons from ICESat-2 to Earth’s surface and back is timed to the billionth of a second to precisely measure elevation.

With so many photons returning from multiple beams, ICESat-2 will get a much more detailed view of the ice surface than its predecessor, ICESat. In fact, if the two satellites were flown over a football field, ICESat would take only two measurements – one in each end zone – whereas ICESat-2 would collect 130 measurements between each end zone.

As it circles Earth from pole to pole, ICESat-2 will measure ice heights along the same path in the polar regions four times a year, providing seasonal and annual monitoring of ice elevation changes.

NASA’s Ice, Cloud and land Elevation Satellite-2 (ICESat-2) will provide scientists with height measurements that create a global portrait of Earth’s third dimension, gathering data that can precisely track changes of terrain including glaciers, sea ice, and forests.
Credits: NASA/Ryan Fitzgibbons


Tracking Ice Melt

Hundreds of billions of tons of land ice melt or flow into the oceans annually, contributing to sea level rise worldwide. In recent years, contributions of melt from the ice sheets of Greenland and Antarctica alone have raised global sea level by more than a millimeter a year, accounting for approximately one-third of observed sea level rise, and the rate is increasing.

ICESat-2 data documenting the ongoing height change of ice sheets will help researchers narrow the range of uncertainty in forecasts of future sea level rise and connect those changes to climate drivers.

ICESat-2 also will make the most precise polar-wide measurements to date of sea ice freeboard, which is the height of sea ice above the adjacent sea surface. This measurement is used to determine the thickness and volume of sea ice. Satellites routinely measure the area covered by sea ice and have observed an Arctic sea ice area decline of about 40 percent since 1980, but precise, region-wide sea ice thickness measurements will improve our understanding of the drivers of sea ice retreat and loss.

Although floating sea ice doesn’t change sea level when it melts, its loss has different consequences. The bright Arctic ice cap reflects the Sun’s heat back into space. When that ice melts away, the dark water below absorbs that heat. This alters wind and ocean circulation patterns, potentially affecting Earth’s global weather and climate.

Beyond the poles, ICESat-2 will measure the height of ocean and land surfaces, including forests. ATLAS is designed to measure both the tops of trees and the ground below, which – combined with existing datasets on forest extent – will help researchers estimate the amount of carbon stored in the world’s forests. Researchers also will investigate the height data collected on ocean waves, reservoir levels, and urban areas.

Potential data users have been working with ICESat-2 scientists to connect the mission science to societal needs. For example, ICESat-2 measurements of snow and river heights could help local governments plan for floods and droughts. Forest height maps, showing tree density and structure, could improve computer models that firefighters use to forecast wildfire behavior. Sea ice thickness measurements could be integrated into forecasts the U.S. Navy issues for navigation and sea ice conditions.

“Because ICESat-2 will provide measurements of unprecedented precision with global coverage, it will yield not only new insight into the polar regions, but also unanticipated findings across the globe,” said Thorsten Markus, an ICESat-2 project scientist at Goddard. “The capacity and opportunity for true exploration is immense.”

​ICESat-2 is scheduled to launch Sept. 15 from Vandenberg Air Force Base in California. For more information about the mission, visit:

266 thoughts on “New Arctic Ice Measurement Satellite with “frickin’ lasers on [its] head”

    • How do the verify satellite elevation? I would also know what the errors is.

      Then we have drag caused by solar wind etc… It would be impossible to have a first order survey done imho. Are they looking for 100th’s of a foot or 10’s of feet or more in differences?

      If the laser is off from perfect plumb by 1 mile, that will give an error in elevation of approx .70 feet. (curvature of the earth). This assumes a smooth non irregular ice pack on water. Of course nothing is smooth and even the irregularities will still have that error.

      • Even if the earth was flat, having the laser be not plumb will still impact the height measurement since the light will have to travel a longer distance both up and down.


            The government is committed to providing GPS at the accuracy levels specified in the GPS Standard Positioning Service (SPS) Performance Standard.

            The accuracy commitments do not apply to GPS devices, but rather to the signals transmitted in space. For example, the government commits to broadcasting the GPS signal in space with a global average user range error (URE) of ≤7.8 m (25.6 ft.), with 95% probability. Actual performance exceeds the specification. On May 11, 2016, the global average URE was ≤0.715 m (2.3 ft.), 95% of the time.

            To be clear, URE is not user accuracy. User accuracy depends on a combination of satellite geometry, URE, and local factors such as signal blockage, atmospheric conditions, and receiver design features/quality.

            So, acurate to a couple of feet most of the time, but could be off by up to 25 feet.


          • Its actually a bit worse as GPS, for calculations, generates an probable location envelop that is NOT spherical. It is a prolate ellipsoid (watermelon shaped) with the long axis aligned with the gravity vector. Due to this GPS is more accurate with lat/long than elevation.
            This is why inexpensive drones will never be delivering packages that cannot survive a 15 foot drop onto your driveway, assuming the Drone didn’t already crash into the ground.
            Short of placing an altimeter on the vehicle your vertical accuracy is about +/- 5 meters using GPS alone.
            Not so bad when flying about far from obstacles, but eventually it needs to land.

          • This is done by stationary ground-based GPS receivers for single points over a period of years. Not quite the same thing.
            Which might answer your question Chris.

          • The question was raised about the accuracy of GPS for measuring height. Specifically how does the paper not address that?

      • You don’t. You measure the difference between the ice level and the level of the sea nearby. This can be done with fair precision.
        The difficulties are:
        1. How deep snow is there on top of the ice (which lowers the ice freeboard)
        2. There might not be any leads nearby (=no measurements on fast ice)
        3. Doesn’t work in summer when there is meltwater pools on top of the ice.

      • ICE sat 1 was 5 inches

        the salt flat at Salar de Uyuni is used as a calibration data set.

        I imagine icesat 2 will do the same calibration

      • elevation: GPS and a ground base satillite laser ranging system.
        calibrated against a known wide area salt flat.

      • Photons travel 11.8 inches in one nanosecond.
        “The roundtrip of individual laser photons from ICESat-2 to Earth’s surface and back is timed to the billionth of a second to precisely measure elevation.”

      • There are plenty of sites that will tell you how it’s done – bearing in mind that orbits do not track exactly the same height above the surface at all times – most are elliptical; they create a computer model of an earth and plot the position of the orbit relative to this virtual world, bearing in mind also that the orbit is mathematically predictable. This is one thing that computer models are actually very good at!

  1. What an excellent project.

    Fantastic information on a huge range of earth’s variables mapped down to e few metres. The data from this will be invaluable.

    It won’t, however, demonstrate empirically that CO2 causes the planet to warm, far less man made CO2. Not that I imaging for a moment that is the satellites purpose.

    Unfortunately, we sceptics will be overrun with ‘compelling’ data and ‘irrefutable’ evidence that man does indeed contribute enough CO2 to the atmosphere (~0.0012% of all gases) using circumstantial conditions to prove a phenomenon that just doesn’t exist.

    I welcome the technology but we all know it’ll be misappropriated.

    • I wonder how they will falsify, er, adjust the numbers? Probably Antarctica and Greenland are rising up “faster than expected” under the reduced weight of ice?

      • “I wonder how they will falsify, er, adjust the numbers?”
        Simple, they’ll do the same thing they do with temperature data. They’ll create a suite of models that make projections of what they want the data to show, and then adjust the empirical measurements to match their models.

      • Ah, yes, the “open minded” skeptics here at WUWT are already trashing the results of a new satellite measurement system even before it launches.

        • If it is as accurate as they pretend, then in 60 years we will have decent data.

          In NO WAY can it be compared to past data.

          but you can BET that is what the alarmist fakers will try to do, (like satellite sea level data or AWS data

          When talking about climate, anything LESS than 60 years, when you have KNOWN 60+ year cycles, is MEANINGLESS.

          • Fred, thanks for the CAPS, so we can be totally clear on exactly what you mean.

            Except you’re wrong, rates of growth or decline are useful information.

          • That’s why we need to wait 60 years, to get an accurate read on the rate of growth, minus the many cyclical environmental factors.

          • Chris, please explain how “rates of growth or decline are useful information” when there is no historical data to compare with such information for at least three years but more like several decades. It is obvious what the goal of such a project is. It is to feed the orthodoxy.

          • Edwin, as opposed to the skeptic position, which is to throw up your hands and say “gosh, we don’t know enough, let’s do nothing.” And of course if you don’t start gathering data, you’ll never have a historical record. So your position is to do nothing, and don’t start any efforts to build knowledge and data. Got it.

        • They can do that because in their minds “raising questions” or merely saying
          “prove it” is counted as “doing science”

          arm chair science. quote popper, quote feynman, raise questions,
          science job is done.

        • Noting all the problems with such a system is now “trashing”?

          As always Chris just gets whinny when we shoot down his latest fantasy.

        • “…trashing the results of a new satellite measurement system even before it launches”

          And why not? If the design specifications indicate that it is not fit for purpose, it should be pointed out before the media starts making claims that can’t be supported. Would you advocate ignoring the obvious?

          • I have addressed several concerns throughout these comments. However, probably the two most serious are that the document provided in a link by Mosher does not support the claim of 5 mm ‘precision.’ Secondly, I haven’t found anything addressing the issue of altitude change resulting from gravity variations over regions that can’t be verified by ground laser ranging.

      • we did land on the moon.

        Now, if you look at ICESAT 1 you can see how they calibrated it.
        You can see how they verified it against other systems
        and you can comapre the models for thickness against the measurements

        They have to do a lot of faking,

        but since the raw data is there you could go try to prove it..
        ya know do science rather than do conspiracy

    • “we sceptics will be overrun with ‘compelling’ data and ‘irrefutable’ evidence”

      I think you’re right HS, if the “Modern (Current?) Warm Period” is anything like the previous Medieval Warm Period, it has legs. We may be in for a century (maybe two?) of warming, giving them data which will dovetail nicely with their humidification apocalypse narrative.

      As always, we live in interesting times.

      • M.W.Plia.

        Hopefully it won’t happen, but we sceptics must condemn the world to another ice age before the alarmists eventually relent and admit they are wrong.

        We have wasted 40 years of productive human development on a scare that will go away quite naturally. Perhaps not soon, but it will go away.

        But make no mistake, until we are entombed in another ice age, the alarmists will maintain they saved the world from AGW by insisting we turn to renewable sources of energy, no matter how pathetic and illogical we maintain wind turbines and solar arrays are now.

        • prediction…
          They will find that they have been measuring it wrong this whole time…
          ..there was a lot more ice in the past

          and it’s worse than we thought

          ….and we will get a min by min play by play every time there’s a crack

    • X,Y and Z axis can be a real bitch…

      john 20:18

      That’ll be my last sermon today. See you all Sunday!

    • “It won’t, however, demonstrate empirically that CO2 causes the planet to warm,”

      Nothing is demonstrated empirically.

    • results they want?

      Simple fact is that today we have no way to measure the thickness of ice in the arctic
      other than some aircraft transects and a few sample holes drilled in the ice pack.

      so you have basically 2 models: PIOMAS and DMI

      figuring out how these models are wrong is important.

      • Steven, explain how this laser satellite will measure ice thickness? Green lasers penetrate ice and snow?

      • “… today we have no way to measure the thickness of ice in the arctic”

        Back in the ’90s NASA was looking for methods. I proposed a method using radar ellipsometry. It never went anywhere, despite SRI showing interest in my proposal.

        It is also possible to collect high-resolution stereo-photography and measure the freeboard of the ice. Those “some aircraft transects” can then be used in the same manner as the quarterly ICESat transects.

        In 1967, NASA flew an experimental microwave imager over the pack ice near Point Barrow. I was on the ice, along with our Eskimo Weasel driver, boring through the pack ice to take temperatures and determine the thickness. So, there is older data available. Its a matter of knowing where to look for it.

        • I had no idea you had this background. Too bad we don’t have a commenter’s bio section…it would be interesting to know more about those who regularly contribute to the conversation.


          • Despite Mosher’s denigration of the WUWT “Brain Trust,” there are a lot of commenters here who are quite qualified to criticize the science of climatology. I have purposely left off a bio’ on my nine articles because I’m a strong believer that a hypothesis should stand on the merits of the argument, and not on the CV of the person presenting.

          • Let’s compare the WUWT Brain Trust’s qualifications with those of Chris and Mosh. The comparative ratio is infinite, since the BT are scientists and Chris and Mosh, umm, to put it kindly, aren’t.

          • It’s eminently clear that WUWT has many varied and qualified commenters. And I do concur that one’s hypothesis should stand on it’s own merits. I think it can be interesting to know an individual’s background, though, especially if the reader doesn’t have the specific knowledge necessary to parse an argument…but I suppose even then it’s fraut with complications about appeals to authority and etc.

            Just thinking out loud…but I love context, and knowing someone’s background can be great context sometimes.


  2. 1970’s satellites began on a high-ice period (Global cooling, doancha know?). It is ironic that this satellite will begin on a low-ice period. ~70-year AMO, etc. anyone?

  3. Fantastic. We will now get panic to six decimal places. Loads more data and grants to manipulate. ( Sorry – feeling a bit cynical these days)

  4. “ICESat-2 will measure ice heights along the same path in the polar regions four times a year, providing seasonal and annual monitoring of ice elevation changes.” I guess there is utility in flying the same path four times per year. My question is how much area will be mapped? Will this method give appropriate data to determine ice area and volume?

    • It will see up to 88 N and S as it has a 92 degree inclination. So it will miss the last two degrees around the poles. It will complete an orbit about every 94 minutes, so the earth will move about 23 degrees per orbit. It will continue that precession at ~23 degrees (may be 21 to 24, but only one constant number, but with the 92 degree inclination countering the rotation I don’t want to do the math to figure it exactly) per orbit and about every 90 days finally repeat the exact track it started with.

      • It takes Cryosat 2 (which is already doing the same thing) about a month to get good coverage of the whole Arctic/Antarctic. Icesat might be faster or slower depending on the measurement footprint. Small footprint = better data quality data, but low coverage per orbit.

        • given the rate at which arctic ice moves i have to wonder how useful the data gathered will be for measuring some of what is claimed will be measured.

    • Based on it covering the same path 4 times a year, it must cover 360 degrees longitude every 91 days or about 4 degrees per day. According to there are 14.8 orbits per day for the original ICEsat.

      If central Greenland is about 75 degrees North latitude, each degree of longitude is 40,000 km x cos(75) / 360 = 29 km, so 4 degrees longitude at 75N will be 115 km. With 14.8 orbits per day, the size of the east-west grid is about 8km over central Greenland. As the article states, the number of readings along the north-south path is very high, nearly continuous.

  5. Lasers are fairly goid at measuring small distances accurately, but…

    From my real old days land surveying, we used the 100 and 200 foot metal tapes with plumb bobs on each end. We adjusted for temperature abd that worked pretty well if the persons were adept.

    Then for elevation we used the philadelaphia rod and a Wild NA-2 automatic level. Did first order work mapping the coastal flood plain of New England.

    Yes, the new total stations do remarkably well and I was around when HP came out with the 3810 and 3820-A.

    A satellite will be a couple hundred to 20,000 miles away in orbit. The laser MUST BE PERFECTLT PLUMB taking the measurement due to the curvature of the earth. If off by several arc seconds or a minute or two, the result will be incorrect and show less ice by increased distance.

    I say we need real competent boots on the ground to verify the real ice level rather than waste hundreds of millions on this costly boondoggle.

    • Actually, if they are off by a couple of arc seconds, they won’t receive a signal. These are pretty focused lasers on both receive and transmit. Also they will be orbiting at 500 km (269nm), so really low earth orbit.

      • Also the satellite is very unlikely to fall into a crevasse or get eaten by polar bears or freeze to death doing winter measurements. It can also measure both poles within 45 minutes of each other.

      • Ever do a traverse surveying? I’ve done a few that had 1:70,000 closures. My average was usually 1:20,000. Had my share of busts too…

        The lasers we used later on required prisms to get readings on the forward tripod target (fore sight) and had them on the rear tripod Back sight). This double confirms andle and distance.

        This satellite doesn’t use prismas, it just scatters light back. This is not good. I’ve used HP, Topcom and Pentax total stations and EDM’s ( electrinic distance meters). For the hell of it we tried an experiment with bicycle reflectors and other reflective materials and never got anywhere close to an accurate reading.

        Even Apollo astronauts left a prism on the moon to get a fairly close distance reading.

        I’m calling these guys out. Technology is great but this method to prove ice thickness will end up with poor results and add fuel to this already smouldering fire.

        Boots on ground with reliable surveying gear is what’s needed.

        This is just a monumental waste of time and money. I know the results can be challenged by both sides….

        • The only surveying I have done is for compass rose surveys for aircraft calibration. To calibrate the magnetic azimuth detector, we first had to do a full survey of the calibration site to get sure azimuth lines. We didn’t care about distance, just accurate directions.

          Though sometimes the weather was bad, nothing like arctic conditions for sure.

        • Mapping regional geology in the 1950s and 60s in northern Canada using compass traverses, pacer and aerial photos, plus “shorelining” by canoe gave pretty good results. Two day compass and pacer traverses in Nigeria from dry stream bed “baselines” accessed by Landrover also worked.

          If you got a bit off line, you tied on to a landmark visible on the aerial photo and distributed your observations along the altered line. You got pretty good at it, especially skillful at extending the direction by lining up visible natural markers with less frequent need for reshooting the line. In the forest , you consciously alternated what side of the trees you passed on as you advanced. I was always conscious of sun angle or shadow and wind angle to assist.

          Making a final map showing the patterns of rock types and structures like folding, faulting (and relative directions of movement along them), strike and dip of formations, ascertaining “tops” of sedimentary and volcanic strata (from sedimentary and volcanic structures, orientation of shellfish valves – convex up! etc.) units that had been folded and overturned over hundreds of millions of years, outlining granitic and other intrusive rocks cutting them and determining relative ages – all to give you the geologic history of a region, including the third dimension, was very satisfying work. Times have changed much more radically than the climate!

        • john said: “Boots on ground with reliable surveying gear is what’s needed.”

          Greenland is 2M km2, with a highest peak of 3,700 m2. Antarctica is 14M km2 with a highest peak of 4,900 m2. By way of comparison, Antarctica is 1.7x the size of the continental US.

          How do you propose to cost effectively survey those two places 4 times per year, every year?

          • Right. I looked online at topographic survey charges, the figure I saw was $400/acre. Let’s be generous and say that for a massive survey it’s only $100/acre. Antarctica is 3.4B acres. So the cost would be $340B 4 times per year, or $1.4T/year. Yeah, cutting out a few billion dollars per year for climate research is going to make a big dent in that $1.4T annual cost.

        • The saving thing in this case is that (for sea-ice) you don’t have to do any absolute measurements, just measure the height difference of the top of the ice and the sea.

          For land ice you do need the absolute altitude.

      • I thought they were using back scatter, not a direct reflection of the beam. Nothing down on the ice capable of doing that anyway.

          • hahaha, good point. sadly, though, the collective brain trust that is WUWT is focused on knee-jerk rejection of anything that might show that AGW is occurring.

          • Chris,
            That is inaccurate. Most of us here acknowledge that Earth is warming, and most will even attribute some small amount to human influence. The problem is to quantify what that human influence is. This particular article is about refined technology that is supposed to provide better measurement of the thickness of sea ice and the loss of continental glacier ice. I, and others, have been pointing out that the claims for accuracy have not been justified, even by information provided by Mosher. You have provided nothing.

          • Clyde, please point out which of your comments points out the flaws or accuracy issues with this new satellite and the laser technology it will use. All I saw was comments about the accuracy of GPS technology when used for positioning or height measurements.

          • Chris,

            I was not the author of the discussion of GPS deficiencies. However, you might try looking at my comment of August 23, 2018 1:48 pm, August 23, 2018 2:40 pm, and August 24, 2018 10:32 am.

            In the future, do your own global searches. Don’t expect me to do your ‘homework.’

    • “I say we need real competent boots on the ground”

      In which case we need to make sure that the satellite measuring top of ice, not top of head.

      • Yes, we had a tension scale (tensiometer) attached on one end. Depending on distance, a certain amount of tension was required.

        The temp adjustment was 1/100 of a foot (+or-) for every 15 degrees F above or below 72F. I’ve done 100F down to -40.

        • Generally, competent personnel back then could correctly guage the tension for most surveys but those requiring first or second order results used the old spring type tensiometer.

          I loved those days. Sending the field book back the the corporate office with black flies and mosquitos squished between the pages!

          • Oh yeah–the field book.
            Rough surveying for the Dept of Highways in Canada’s hottest and dryest region. Midway between Lillooet and Lytton on the sunnyside of the bench.
            At the top right-hand corner of the page we had to note those on the crew and what the weather was like.
            I recall 40 days without a cloud and temps above 100 F. Guys running the Cats had a rough time.

    • When at school I had summer-jobs surveying. The first one was on Vancouver Island running profiles across a river.
      The agency was a left over from the 1930s “New Deal” in Canada called the “Prairie Farmers Rehabilitation Agency”. Or “PFRA”.
      Which we translated to: “Pray For Rain Always”.
      Can’t survey when it’s raining.
      As to the satellite, it will be better than the current system and the measure will likely include annual comparisons.

    • The issue is clouds. Lasers can’t penetrate clouds so they can only take measurements over cloudless areas, which means they will have to stitch together data from multiple passes, reducing the temporal accuracy of the data.

      • Scientific photons do affect one thing. Carbon trading and carbon taxes all increase exponentially, the more scientific photons that are measured.

  6. I could see somebody making a stupid joke about how the lasers will melt the ice they are measuring.

    Oops!, we dun turnt them lazers up 2 hi, so we dun melted thu sno.

    Hey, Jeba, cum ova heer and hole this candill on this iees sickle, so i kin cee how tu masur thu linkth.

    • Was thinking the exact same thing. “Houston, we have a problem, laser calibration, cooling issues, orbital decay, data transmission….oh my”

    • This reminded me to go look at NASA’s site again to see if they have new information, “latest images” are still from 2014.

  7. ATLAS will fire 10,000 times each second, sending hundreds of trillions of photons to the ground in six beams of green light. The roundtrip of individual laser photons from ICESat-2 to Earth’s surface and back is timed to the billionth of a second to precisely measure elevation.

    Golly gee ma, how do they even count that many photons. /sarc

    Obviously this was written by a professional writer (who took zero math and science courses).

    Light travels about a foot in a billionth of a second. It’s a round trip so it sounds like one sample can resolve about half a foot. Not bad actually.

    • It will be accurate in time of flight to about 800 picoseconds, so plus or minus about 4.5 inches.

    • The light travel time will be the collected data. That data will have to be run through a model to convert it to elevation information (relativity, gravitational, temperature variations I suppose).

    • cB, I find it interesting you introduce the speed of light thing.

      The raising of the TOA radiative cooling level (where the balance is found with incoming solar) from human activity emissions CO2 is not in question. Such is the science. The issue, or debate, concerns the phenomenon’s magnitude.

      So ok, there may be some effect, but given the speed of light I doubt the approach to equilibrium is retarded enough to change the climate.

      I’m with Freeman Dyson, IMHO there might be some effect at night in the colder regions of the planet, such that freezing is altered a few minutes (maybe seconds) here and there….so what?

      These people (Al Gore and the alarmists) need to find a new and different hobgoblin to feed their neurotic and delusional requirements…..any ideas? Sasquach maybe?

    • But will NASA know the altitude of the orbit with the same accuracy and precision as the difference between the ground and the satellite? If not, then the information will not be all that useful!

        • Mosher,

          I’m left with the impression that you don’t understand what you are reading. The link you provided speaks to the ATTITUDE of the ICESat-1 laser. That is, constraints on the pointing direction and the error resulting from misalignment and sloping surfaces. The article mentions a nominal altitude of 600 km for purposes of the analytical error calculations. What is of concern is the combined errors, but especially how accurately the altitude of the satellite is known. From the GLAS Measurement Requirements, “In summary, the error budget allows 10 cm instrument precision, 5 cm radial orbit position, 7.5 cm laser pointing knowledge and 2 cm or less for other error contributors.” for what appears to be a total error in precision of +/- 24.5 cm (~+/-9.6″).

          What is of concern to me is whether the assumption of the 5 cm (5.0?) radial orbit position is warranted considering that the altitude will only be spot-checked rather than continuously monitored as per “The GLAS orbit position will be obtained with the Global Positioning System (GPS) and ground-based Satellite Laser Ranging (SLR).” For areas where the ice is melting, the gravitational attraction will be decreased and the satellite will rise in altitude, which will increase the distance between the ice and satellite. Thus, it will appear that the ice has melted more than it has!

          Your claim below of “Icesat 1 did 5 inches” is not supported by the document whose link you provided. However, more importantly, the document doesn’t speak to my concerns of constraints on the orbital positional errors, which are probably unknowable out in the middle of Antarctica.

    • Yes for making sure laser pulses would arrive simultaneously I used that approximation (1 foot/nsec). They’re claiming freeboard measurement to 3cm so that implies path length difference of 6cm or 0.2nsec.

    • Silly boy. That’s how they will explain that although the glacier “seems” to have gained height, it’s actually lost mass because the land has rebounded from the reduced weight of ice.

      • Of course not, they will subtract that out with sufficient “adjustment” to maintain the expected loss of glacial ice.

        • Sounds as if glacial isostatic adjustment like in the sea level measurement fiasco IS GOING TO REAR ITS UGLY HEAD.

          • Actually not so much. That is the big problem with GRACE raw data which for Antarctica are actually not significantly different from zero, so the “catastrophic melt” there is actually 100% GIA adjustment.
            Direct measurement of the height of the ice is much less affected by GIA uncertainty since the density of ice is only a third or a quarter of the density of the underlying rock.
            The ugly head in this case is instead that the density of the snow for the about 300 feet down to where it turns to solid ice is known to vary geographically, but there is very limited data.

  8. It is going to be orbiting at 500 km altitude. The stability of the orbit and the ATLAS laser system’s ability to measure its own altitude will determine the resolution of the instrument. Same problems the GRACE satellites have, just exactly how far up are they at any given time?

    NASA does not like to discuss theses sort of things. Error bars that are too large embarrass them.

    • They are measuring satellite altitude with a More sophisticated version of a sextant. They call theirs a “star tracker.”

      They claim precision to 3 cm, and then they call 3 cm “a fraction of an inch.” The laser beam’s “footprint” on the ice is 10 meters. Obviously there will be high and low spots in a patch of ice this large.

      NASA’s track record certainly leaves a lot of grounds for suspicion of false claims of precision.

  9. How will they prevent this satellite from suffering from the problems that have plagued the satellites that allegedly measure the height of the oceans?

    1) How do they know the height of the satellite “to within the width of a pencil”? Gravitational changes beneath the satellite (including height of the ice) will impact the height of the orbit. And not just directly under the satellite either.
    2) Ice is not smooth. How good are the algorithms for detecting crevases, water on the ice, snow, etc.?
    3) Anything that impacts the density of the air will impact how fast the light travels through that air.

    • I remember the first gps we used surveying, back the it cost $33,000 usd back in 1984. It took days to get a close reading from several orbiting satellites. We said to heck with it and did a star shot on polaris with better results.

      They have improved since but, the plumb thing bothers me a lot.

      “It’s tough being a skeptic”
      john 20:18

    • Glaciers move, tides happen then you have useless lawyers, alarmists and politicians.

      “If it ain’t plumb, the bar just got lowered”

      john 20:18

    • Measuring the height of ice in Greenland or Antarctica is way easier than measuring the height of water in the middle of the ocean.

      Everywhere in Greenland or Antarctica is ‘reasonably close’ to some bare rock, be it a mountain top or shore line. That provides a calibration point. Out in the middle of the ocean, there are no ‘reasonably close’ calibration points.

      Having ‘reasonably close’ calibration points solves a myriad of problems. Now, rather than doing absolute measurements, you’re doing a relative measurement, similar to differential GPS.

        • There are ways to confuse electronic equipment that cause problems like overheating and excess battery use. My favorite is called metastability. So, in a manner of speaking, electronic equipment can get sea sick.

          • It’s not a problem as long as you keep the bit bucket emptied.

            In searching for bit bucket I noted a huge difference between Google results and those from DuckDuckGo. In this case, DDG was far more useful.

          • commieBob

            I use DuckDuckGo whenever possible. Unlike Google, it doesn’t track your searches. You should be able to nominate it as the default search in your browsers settings.

      • You are assuming that the bedrock in Greenland and elsewhere is not experiencing isostatic rebound. If it is, then it will make it look like the ice is melting more than it is. They will need differential-GPS calibration stations to do it right/

        • The rate of post-glacial rebound is 1 cm/yr or less.

          As long as the calibration point is ‘reasonably close’ to what’s being measured, it will be rising at the same rate as the bedrock underlying the ice. In other words, it will remove the effect of post-glacial rebound from the measurement.

          • You are both wrong. If the bedrock is rising fast enough to maintain isostatic equilibrum it will completely hide the gravitational effects of melting ice, not make it look larger.
            However it does not do that, as proven by the fact that the isostatic rebound is still going on in Canada and Scandinavia.
            And there is not nearly enough calibration points close enough to accurately determine the amount of rebound. In Greenland the situation is fairly good, but even there there is a great deal of uncertainty, particularly since the rebound rate depends on local rock viscosity, which in the Greenland case is probably affected by the nearby Iceland hotspot.
            GIA data for Antarctica is almost pure guesswork. And none of the GIA models fit the actual data.

          • And there is not nearly enough calibration points …

            In this case, the calibration points are bare pieces of rock, like mountain tops or shoreline. They act the same as surveyor’s reference markers. In the case of post-glacial rebound, they will rise along with the rest of the bedrock. The satellite measures the difference between their height and the top of the ice. It improves the accuracy by about an order of magnitude.

          • I was assuming that any calibration sites would be on the edge of the ice sheet and would be experiencing post-melting isostatic rebound, thereby requiring differential-GPS leveling to correct for the rebound..

      • “Everywhere in Greenland or Antarctica is ‘reasonably close’ to some bare rock, be it a mountain top or shore line.”

        Only if you count 1000 kilometers as “reasonably close”. There is NO exposed bedrock anywhere in inland East Antarctica.

        That is the big problem with GRACE data in Antarctica. Very limited GPS data, and none of the GIA models fit the data there is.

        • Only if you count 1000 kilometers as “reasonably close”.

          That’s why I used the quote marks. 🙂 Obviously the farther you are from a reference, the worse your accuracy.

        • it’s apparently close enough for extrapolating temp readings from ground based thermometers ,ask mosher.

    • ” 3) Anything that impacts the density of the air will impact how fast the light travels through that air. ”

      Were you thinking, twinkle twinkle little star?

      • I would call this a very thorough analysis of the problem of the orbital position, which largely justifies the estimate of +/- 5 cm radial position (although it didn’t specify whether that was 1 or 2 SD precision, or accuracy). It is far better than most climatology papers I have seen! The only thing I didn’t see explicitly addressed is topographic leveling of the elevation of the Satellite Laser Ranging (SLR) stations, which can be affected by isostatic rebound on the edges of the ice sheets. This isn’t a problem particularly in the interior of continents. But it is an EXPECTED problem on the periphery of the major ice sheets, for which this satellite was designed. Because of mantle hysteresis, or time lag, melting ice will not be be gravitationally compensated immediately, so the satellite can be expected to rise in altitude from the loss in ice. On the other hand, the SLR stations will be rising, giving a lower-bound on the distance difference between the satellite and the SLR calibration. So, unless I have missed something, there is an oversight in not providing differential-GPS leveling for elevations of SLR calibration stations on the edge of the ice sheets.

        However, I’m not looking for a job.

  10. They will “discover” that 1,1,1,2-Tetrafluoroethane increased the speed of light through the atmosphere causing erroneous measurement of deeper ice thickness. Thus requiring adjustments to the measured values.

  11. Yawn….

    They will simply “adjust” or “guess” at past numbers to make sure it shows a MASSIVE MELTING!!!!

    • Bruce Boelter

      They used laser beams in the 1800’s to take ice measurements they can compare with, surely?

      • No, but there’s a bristlecone pine that has a feeling it knows how much ice was there and it told me it was a schistload more than today.

  12. Watch NASA ignore the findings of the new satellite and use less accurate methods when the data doesn’t give the results they desire, like they did with their satellite temperature data that didn’t show the warming the climate models predicted.

    A prediction – most of the ice loss (but not all) will be a result of ‘adjustments’ to the raw data.

  13. Lasers don’t see through clouds, which is why the LIDAR mapping used to find lost cities under the jungle canopy in Honduras was done by planes at relatively low altitude. Aggregating and matching data while compensating for missed areas due to cloud cover sounds like other-level complexity. But climate scientists are really good at making up data that doesn’t exist (infilling). Should be interesting to see how they handle this.

      • Steven Mosher: “except its not climate scientists who do this work … ITS ENGINEERS”

        Climate scientists are not engineers. Thanks, that confirms my long-held suspicion. Can you help list the qualities that climate scientists are lacking?

      • Building instruments for accurate measurement is an engineering task. Interpreting the measurements and accurately factoring for instrument precision and missing measurements is the realm of statisticians and climate scientists.

        It is climate scientists who are gridding and infilling global temperatures from terrestrial measurements, not engineers. They create data that doesn’t exist in the real world over large expanses of the globe to estimate global temperatures and trends. The more remote the weather station, the greater its influence on global temperatures. This is not science, it’s statistics. This abuse and misuse of statistical methods, especially in pronouncing global trends, falls squarely on the shoulders of climate scientists. It’s no surprise that there is a significant difference in the results of satellite and terrestrial measurements of temperature and sea level and their trends.

        Engineers built the LIDAR but it has limitations. Lasers are incredibly accurate for measuring but they can’t measure through clouds. Statisticians and software engineers have to develop algorithms to stitch together data from multiple passes, which results in composite snapshots that reduce the temporal resolution and accuracy of the data, especially over areas that are often clouded, like high mountains. Adding complexity, to measure elevation changes over time the altitude of the LIDAR instrument must be established with high precision. Over long periods of time, the inaccuracies may not matter much and we will probably get a reasonable idea of glacier mass changes, probably (hopefully) better than the GRACE satellite measurements.

  14. Here’s a brilliant thought: If you want satellite laser measurements to confirm a melting arctic, then make them powerful enough to melt the ice they are measuring. This way you can swear by laser precision, while hiding the fact that the lasers used were alien-death-ray strength.

    You’re welcome, NASA. Just trying to help you stay consistent in your narrative.

  15. And to be orbiting every 95 minutes, its gotta be hanging pretty low.

    As how mirages form, don’t they need a pretty accurate temperature profile for the atmosphere they’re shooting through. Refractive Index changing the speed of light and all that shizzle?

    Many many moons ago I caught a programme about the surveying of India (start with a known straight line then construct triangles) and that was when Mount Everest was discovered.
    Politics of the time said they couldn’t get anywhere near it but they still took measurements to work out where it was and calculate its height. It was obviously Pretty Big.

    Back in London to a room full of boys (and girls?) with log tables, pencils & paper, JUST the atmospheric correction that needed to be made altered the height by 500 feet
    They got it pretty damn close considering how far away they were. Too long ago to recall the actual figure but…….
    (Assuming you cannot leave India, just how close can you get to Mt Everest’s summit?)

  16. Interesting. One billionth of a second equates to 30cm resolution on the return path, so 15cm on distance between ground and satellite per shot. The ‘pencil’ width accuracy, 5 mm, must come from the many, presumably independent, measures during a pass. However that claim of accuracy is only valid if they also know the exact position of the satellite itself to a degree better than those 5mm, otherwise the orbital uncertainties become a huge systematic error, a bias, on the measurements. I really like to see proof of that accuracy.

  17. “A laser has been used to generate small clouds on demand in lab, and real-world experiments suggest this could be a way to call down rain when it’s needed.”

    “Rarely acknowledged in the debate on global climate change, the world’s weather can now be modified as part of a new generation of sophisticated electromagnetic weapons. Both the US and Russia have developed capabilities to manipulate the climate for military use.”

    “While the substance of the 1977 Convention was reasserted in the UN Framework Convention on Climate Change (UNFCCC) signed at the 1992 Earth Summit in Rio, debate on weather modification for military use has become a scientific taboo.”

  18. I have a problem with the claims about precision. On the poster it says the precision is 1 inch, or 3 cm, not a pencil-width. Which is it?

    Next, and I presume they compensate for this but don’t talk about it: the speed of light.

    It turns out the speed of light is not constant. It varies depending on the direction you are travelling at the time. There is a difference between moving towards or away from the constellation Leo. The difference is quite easily measured. So, if they make a measurement on a certain date the Earth will be moving in some direction, and the satellite moving relative to it, and the get some number. Then 8 months later they measure again but now the Earth is in a different place, heading in a different direction, and the satellite too. There will be a time to return variation even if the ice is exactly the same height. That will be recorded as either an increase or loss in surface altitude.

    Has the magnitude been evaluated?
    How are they going to compensate for that?

    • ” It varies depending on the direction you are travelling at the time.”

      NOPE, you have not heard about Einstein’s paper on special relativity. The speed of light is ALWAYS constant, and is independent of your frame of reference.

      • How hard can it be, the satellites are being affected by gravity differentials, the sea surface and ice move at a different rate determined by air pressure, nothing that can’t be adjusted to the land based GPS stations connected to the continents floating atop the mantle.
        One more variable and we can make it wiggle its trunk.

      • The speed of light is constant however, moving towards or away from it changes the frequency like sound. It also changes the time variation. The db level also changes.
        The irony is that a green laser is usually a co2 one. There are too many problems with this.

  19. “will measure the average annual elevation change of land ice covering Greenland and Antarctica to within the width of a pencil, capturing 60,000 measurements every second.”
    Do these guys understand LLN or is it a panacea for all sorts of errors? Using satellites taking many measurements sounds fantastic but when the billion tonnes of ice is mm changes over millions of square kilometers, I suspect the only trend will be the systematic error not corrected or due to corrections to better fit measurements from an instrument gaffer taped to an off-season crop duster.
    Surely measuring temperature trends would be easier?

  20. The USA has finally gone mad!
    There’s no ‘business case’ for this toy.
    It’s a left wing NASA funded nerdity to bolster their global-warming scare campaign.
    They would’ve been better designing a weapon to destroy China & India who are the current # 1 enemy if you believe CO2 is going to kill us (as NASA does).
    So what NASA really decided is . . . ok let’s send ‘observers’ to the genocide and we’ll report back on casualties as they occur. But under no circumstances will we intervene in the killing.

    • The Trump administration must stomp on NASA overreach now.
      Overreach perniciously underlays the demise of every great civilization . . .

      • Greenland!!!!!!!!!!!!!!!!!!! They are scared of it melting. Ha Ha HA Ha Ha Ha Ha
        Greenland has 2,850,000 km3 of ice.
        All of it would have to melt to raise sea level by 7 metres. This is just not going to happen especially even with a 4C average global temperature rise which is at the high catastrophic range of IPCC predictions. You just cannot melt that large a block of ice with air temperatures 4C higher . This is because you are dealing with averages here. The summit which is 2 miles above sea level in the interior has an air temperature range of -26C in winter to 0C in summer. Summer in this part of Greenland is only 2 months long. Temperatures in the other 10 months of the year are below
        -10 C. So 2 months of summer is just not enough time to melt an appreciable amount of ice. Increasing the average global temperature by 4C will not make the interior go above freezing because of the elevation.
        Additionally, the weight of the Greenland ice has depressed the interior of the continent and disrupted any drainage that existed prior to being covered in ice. If the ice should be completely melted, a significant fraction of the water won’t make it to the oceans until isostatic rebound removes the ‘bowl.’ The bottom line is that theoretical calculations converting the ice volume of Greenland to an increase in ocean level overstates the immediate effect.

        I would also like to draw your attention to this graph

        It shows the alltime record summer temp for Summit station in inland Greenland. Notice that it barely got above 0C. Since summers are only 2 months long here how in the hell is Greenland supposed to melt any appreciable amount even if global temps went up 4C. The summit is 2 miles high and the mean thickness of the ice in all of Greenland is 2135 metres or 7000 ft. Since this total of ice is 2850000 km3 , how would this melt in 2 months? It wouldn’t. Fall and winter would come and the ice would refreeze. Spring would come again and as you see on the graph there wouldn’t be any melting in the spring even if global world temperatures soared above an increase of 4C. Sure Greenland has been losing ice mass over last 20 years but this has happened thousands of times in the past. There was less ice at the end of the 1930s in Greenland than there is today. A new study by Niesen et al.,2018 shows that 8000 years ago was 2-3 C warmer than today with peaks as high as 5C higher and the Greenland ice mass diminished only 20% in 3000 years at those increased temperatures.

        To further cement this hypothesis of Greenland ice sheet not melting from of top, there have been studies that the melting is happening from underneath because of a volcanic ridge extending from Iceland right to the Arctic. Even the alarmist scientists are admitting that the top of Greenlands interior ice sheet is not melting and that the upper surface every year gets fresh snow/ice and the reason that there is a net loss of ice is the amount of icebergs calving off on the shore line. These icebergs have calved off for millions of years and the volcanic activity has come and gone for millions of years.The alarmists will argue that the calving of the icebergs on the coast of Greenland is increasing with global warming.
        However, that demonstrates a lack of understanding of just how calving works. Calving is a breakup of ice shelfs at the coast caused by pressure from the ice sheets as the ice is forced to the sea. Calving is just as likely to happen when it is cold or warm. Calving has been going on ever since Greenland formed ice sheets.

        All of Antarctica melting is a worse farce 1000 times over for basically the same reasons.

        The global alarmist position is a farce on every level.

  21. NASA still doesn’t understand what specular reflection is: “The bright Arctic ice cap reflects the Sun’s heat back into space. When that ice melts away, the dark water below absorbs that heat.”

  22. I’m familiar with the instrumentation on this satellite. It’s known as the Coherent Radiation Altimeter Package (CRAP).

  23. One thing is for sure- soon as the new measurements start we will get: ” It’s much worse than we thought!”

  24. “Although floating sea ice doesn’t change sea level when it melts, ”

    The ice is not uniform in salt content, therefore there is a small increase in sea level rise. the estimate of the Arctic melting would be 20mm. Not worth worrying about.

  25. Note they are going to track ice melt and sea level rise even if it stops melting and sea level goes down. Talk about bias! They should at least have been neutral on the tech at this stage – simply will monitor sea level and measure ice would have made me less suspicious. Carl Mears showed us you could, without skipping a breath, wrench a 2 decade temperature pause upwards into a galloping warming at will by fiddling the instrument data. How are we to straighten all this destruction out when this virus is over?

  26. Laser distance measurement technology won’t cut any ice with the BBC[1], who, presumably with the blessing of Roger Harrabin, will continue to measure ice with their traditional method: counting the number of “unprecedented” journeys by ships through the cyclically-ice-free Arctic passages.
    “Until now the the [Arctic] route has required an escort of expensive nuclear icebreakers to accompany any vessel. But global warming, which has raised temperatures along the route during the summer to over 30°C, is changing its viability.”
    [1] BBC (unattributed author): Container ship to break the ice on Russian Arctic route [because global warming]

    • Wonder how they did it between 1933 and 1957 when the first nuclear icebreaker (Lenin) was completed.
      Icebreakers are usually needed, yes. Nuclear no, not necessarily.

      By the way swedish conventional icebreaker Oden is currently at the North Pole with a research team. It had considerable difficulty getting there though. The captain reports the worst ice conditions he has ever experienced, starting 2005.

  27. Nothing new, Cryosat 2 is already doing this:

    However the technique has limitations. Ice freeboard can only be measured if there is open water nearby to measure the freeboard from, so no data for fast ice without leads near the coast.
    Also no measurements in summer since there is no way to distinguish open sea and meltwater pools on top of the ice.

    Also ESA (which operates Cryosat 2) is honest enough to admit an uncertainty of several decimeters in measurements. However NASA who measures sea-level (vastly more difficult) with 0.1 mm precision will undoubtedly overcome such problems with the aid of some magical algorithm.

        • given the speed of light,
          given the time for the laser signal to hit the surface and return….design an algorithm…ie formuls,,ie model… to calculate the distance.
          hey dummy… do you think we measure distance to the moon with a ruler.


      • You must love that link since you keep pushing that at us, regardless of what the commentor states. Already basic errors in the link have been pointed out, like the “accurate to a pencil-width” actually is a very fat 3cm, and the uncertainty in the distance measured is going to be approx 15 cm based on 800 picosecond measurement accuracy and variable speed of light through a heterogenous medium. So since you keep cutting/pasting the link without revealing how to overcome these and other problems, maybe you should take a break from trolling and read it for yourself.

      • mosher,

        From the ATBD document, which I suspect you didn’t bother to read:
        “The predicted radial orbit errors based on recent gravity models (e.g., JGM-3 or GM-96) are 19-36 cm.” This is from existing Earth gravity models. It doesn’t address the concern I raised about annual changes in gravity through the addition or loss of snow. In any event, I don’t see how the claim of 5 mm measurement error is justified when the altitude of the orbit will have an estimated error of 190 to 360 mm!

        Instead of insulting people, how about showing that you actually understand the problem?

  28. In many fields of science, researchers are forever hoping for instruments that detect and measure lower and lower quantities. I went through this with analytical chemistry in the 1970s, noted for the invention of the Atomic Absorption Spectrophotometer and other instruments.
    What happens is that every Tom Dick and Harry, irrespective of ability and qualifications, can eventually get access to greater and greater sensitivity. As was demonstrated so vividly with the Geiger counter for radioactivity, this generated huge numbers of alarms, scare and zany amateur theories.
    Now we see it happening again with laser range finding. One of our sons is a graduate surveyor who warns us from time to time about expecting too much from instrumentation. Other surveyors here just now are alert to the same problem. Also, I spent a couple of years working with modern lasers of various types, so I can but agree with his caution based on what I learned.
    We have seen some consequences from satellite laser estimates of sea level change. I do not get the feeling that genuine surveyors endorse stretching the technology so far, so fast.
    Problems arise, big problems, when premature policy changes are made in governments, based on cutting edge speculation from instrument performance that really should be wound back until the uncertainties are properly assessed and understood. The bogey man is often bias, not precision, for those who know the difference. Geoff.

  29. This subject provides a great opportunity to watch skeptic group think in action.

    lets start with a typical skeptic claim

    the ice is thicker now

    You can see this claim and the DMI charts all over twitter and even from Joe B

    here is joe B using DMI products

    But DMI thickness and volume charts are MODELLED DATA, not measurements, but MODELS

    Make note of this.

    1. Skeptics who use DMI never point out that it is modelled data.
    2. Skeptics never question this data.
    3. Skeptics never raise the question of how the thickness was measured.
    4. They only use the data when it suits their narrative.

    hey skeptic, have you ever seen anyone use DMI data? did you questio it? did you know it was a model?
    or did you like what it showed and never paused to ask questions? Did you just accept it without
    asking “hey? how do they measure thickness?”

    Now, read this thread.

    See how many times people question the collection of real data. before its even done
    See how many people cant believe the measurements before they even happen
    See how many people want to see proof of the height accuracy.

    Then ask yourself. where were these skeptical questions when Joe B presented

    MODELLED data of thickness

    where were these skeptical questions when heller presents DMI as if it is measurements.

    I mean seriously guys. none of you have guts to challenge other skeptics when they present modelled data that you happen to like. And when someone at nasa builds a system you could only dream of working on, you trash it before reading the engineering documents.

    In one case you are eager to believe and in the other case no amount of sound engineering will convince you.

    • Completely true. Paywalled papers that support AGW are immediately attacked here, even though 90% or more of commenters have not read the paper. Any paywalled paper that casts any doubt on AGW – for example one a few years ago saying that year’s CA fires were not linked to AGW – are immediately cheered. Once again, by folks that haven’t even read the paper.

      Yet those same posters call themselves “true skeptics” that don’t have preconceived notions. It’s laughable – when folks trash a paper that supports AGW even before they read it, or attack a new satellite that will allow better measurements on ice thickness before it even launches, they have zero credibility in claiming they are an open minded skeptic. Zero.

      • Open minded, yes.
        So open minded that the brain falls out, no.
        Facts contained in your comment, zero.

        • Prove me wrong. Provide a link to a WUWT post about a paper that supports AGW that was given a reasonable evaluation by commenters here.

      • Chris,
        You said, “…attack a new satellite that will allow better measurements on ice thickness before it even launches…”

        In my case, I’m looking for evidence that the accuracy will be what is claimed. I have raised questions about the control on altitude (which is critical!) over regions where the ice is melting actively. The satellite should be able to measure floating-ice free-board with greater accuracy than ice on Greenland or Antarctic. However, I’m concerned that the data for the continental ice sheets will be misused and once the data are published, they take on a life of their own. I have yet to see anything from you or Mosher that allays my concerns about altitude determination over the interior of either ice mass. AND, the GLAS document provided for ICESat-1 suggests an error almost 50X that claimed for ICESat-2!

        I’m just asking for clarification for what appears to be contradictions and oversights.

          • mosher,
            As a matter of fact, I DID give the ICESat document (GLAS) a ‘hard’ read. And, as I quoted elsewhere, the document gives a total system error of 245 mm for a claimed error (accuracy/precision?) of 5 mm. I’m left with the impression that you didn’t bother to read the links you provided, or perhaps, didn’t understand what you were reading.

            You should be embarrassed by your ‘drive by’ comments. Strangely, you aren’t! That says a lot about your personality.

      • chris, note none of these genius guys caught that joe b used modelled data.

        they have zero engineering integrity.

    • that is some claim. personally i don’t think any of the data is fit for the purpose to which it is currently used. temp data,satellite data the lot. i applaud the fact that people are (in some cases) trying to improve the situation but there is a long way to go to claim certainty anywhere near the level it is claimed today.

  30. Maybe we will finally get a satisfying explanation of why, some 30-40 thousand years ago, Mammoths in Siberia were flash-frozen with green plant matter still in their stomachs.

    • They weren’t. Actually most are pretty well rotted. And almost all dead animals will have food matter in the stomach.

  31. Surely one day all these satellites are just going to collide with each other lol. Every other day new satellites seem to be launching into space. Then again, the size of space is unfathomable.

  32. ❝… will measure the average annual elevation change of land ice covering Greenland and Antarctica to within the width of a pencil, …❞

    Even this, is insufficient. Let’s get a ball-park estimate of the annual ice-mass loss, and compare that to the width of a pencil.

    Greenland’s ice area: ”The Greenland Ice Sheet extends about 1.7 million square kilometers (656,000 square miles), …”

    One millimetre of ice, across 1.7 million square kilometres:
    (0.001)(1.7•10⁶ ㎢) = 1.7•10³ ㎦
    1.091 cubic kilometres of ice equals one Gigatonne, Gt.
    (1.7•10³ ㎦)÷1.091 = 1,558 Gt of ice. The DMI .DK blog complains of Greenland loosing ice at 200 Gt per year.
    If one millimetre of ice accumulation, on the existing ice area of 1.7 Million kilometres squared, adds 1,558 billion tonnes of ice, then, how many millimetres of ice represents the DMI .DK complaint of 200 Gt?
    (200÷1,558)=0.12837 … a bit more than one-tenth of one millimetre. Do you really think that ICEsat is able to measure ice thickness to better than 0.2 mm, which is a small fraction of the width of a pencil lead, let alone, the pencil itself?

    Even if the frickin’ lasers were absolutely precise and accurate, in their ability to measure the distance between a flat surface and the orbiting satellite, the active areas of glaciers, aren’t flat. This is the precision attitude determination (PAD) problem.

    Martin 2005:”For example, a 1 arcsec pointing error to a 2° slope produces a 10 cm error in derived elevations, rising to more than a meter per arcsec for a 20° slope.”

    King 2017: ”ICESat-2’s attitude determination requirement is more stringent at 3.7 micro radians or 0.76 arc seconds in attitude determination knowledge [2],[8].” That’d be around seven centimetres of error.

    The satellite data has to be manipulated. Altimetric satellites, like ICEsat, cannot tell what caused the height change, like the land moving down or up, compared to ice being lost, or accumulating. In order to subtract out the solid crustal movement, a GIA fudge-factor is involved. This is arrived at, by using measurements, massaged with computer models.

    The GIA reported by Khan 2016 was “1.4mm ±0.1mm”, yet, a year later, van Dam 2017 reported “1.44mm ±0.144 mm” … so, we’re anticipating that the satellites can resolve a less-than 0.2mm per year change of ice mass, when the GIA fudge factor is ±0.144 mm?
    0.2±0.144 mm? Horse poop.

    Then, there is POD … Precise Orbital Determination. Geodesy, the problem with determining, exactly, where the planet’s centre of mass is, at the moment. Given the vague PR statement, ❝… will measure the average annual elevation change of land ice covering Greenland and Antarctica to within the width of a pencil, …❞ I will, for the moment, assume that POD and Geodesy problems have been solved (though, I doubt it).

    King, Jennifer Michele 2017. “Investigation of a nonorthogonal gyroscope model for ICESat-2.” Master’s Dissertation, M.S.E. University of Texas at Austin

    Martin, C. F., <iet al. 2005 “ICESat range and mounting bias estimation over precisely‐surveyed terrain.” Geophysical Research Letters

    van Dam, Tonie, et al. 2017 “Using GPS and absolute gravity observations to separate the effects of present-day and Pleistocene ice-mass changes in South East Greenland.” Earth and Planetary Science Letters

  33. Again this is one of those expensive data collection schemes that will mean what exactly? Until it has been up and operating for a decade or long it will mean little since we have never measured the ice this way before. However I will bet that the year after it has done the four seasons we will be reading headlines of gloom and doom.

  34. Yesterday, Arctic sea ice extent was higher than on that date in 2007, 2011, 2012, 2015, 2016 and 2017. The NW Passage is still closed, and it’s looking as if it won’t open this year at all.

    Two Arctic cyclones lowered extent in 2016, as had single cyclones in the record low years of 2007 and 2012. Wherever sea ice ends up this year, it’s likely to be higher than 2016. So the upward trend in place since 2012 and flatter trend since 2007 should remain intact.

    Meanwhile, Antarctic sea ice is in the normal range, after peaking in 2014. Antarctic sea ice grew in the satellite record since 1979, while it was falling in the Arctic. Thus, no CO2 signature in sea ice data.

  35. Anthony, I couldn’t wait till Sunday for this… Wind Scamster and Senator Angus King (I-ME ..and his son who wasva VPbat UPC Forst Wind ) has their sights set on Greenland.

    He used his office as Maine Governor in conjunction with UPC/ IVPC/ Evergreen/ First Wind et. al. To further his crony interests. As a Senator on the Intelligence Committee has his offshore banking and energy interests focused on this very issue.

    The satellite will not measure ice but will be looking for mineral resources.

  36. Mosher,

    Too tired to scroll down to find your contradiction again. Controlling attitude by GPS would require an awful lot of fuel, of which they are limited. Gyros, can be done from the solar cells. Think, man…

  37. Altering the angles yaw, pitch, and roll “Attitude” at which the satellite orients the Earth obviously requires far less energy than adjusting the altitude of the satellite. The laser must shoot straight down otherwise useless data. They are constantly adjusting the aim of the laser to control for this. The laser is small.

    The satellite is over a ton, but far above the Earth. It must stay at a controlled ALTITUDE for several years. Fuel must be burned to control the Altitude, not the Attitude.

    Twist your little finger, and then run around the block. Which required a larger effort?

  38. Just one more comment my friend, They have an extremely sophisticated system of Inertial Guidance Gyros on this satellite, which is already in orbit. What are there for? To keep the laser pointed Plumb which means straight down, O.7 ArcSeconds apparently. Innovative system of Gyros, four of them oriented towards the four joints of a Tetrahedron, very innovative.

    Read, and Understand….

    • still not good enough to match the claims according to nitpickers post above.
      “King 2017: ”ICESat-2’s attitude determination requirement is more stringent at 3.7 micro radians or 0.76 arc seconds in attitude determination knowledge [2],[8].” That’d be around seven centimetres of error.”

    • Michael Moon,
      But Steven and Chris have not addressed the question of how, when the satellite makes a repeat pass over an area of Greenland or Antarctica that has experienced melting (i.e. a loss of mass) NASA will be able to tell how much the satellite increases its altitude because of a decrease in gravity. If they try to model the gravity, they will get a value that is too low because the estimate of the amount of ice lost will be too high. So, I have to conclude that they either don’t have the answer, or don’t understand the problem — or both.

  39. What’s the point of having that most amazing technology to measure ice and climate and stuff, when the data will be processed in the hands of the likes of Josh Willis? (Wizard who magically changes cooling into warming.) Depressingly pointless.

  40. Actually, thee timing accuracy has to be closer to ,02 billionths of a second. Light travels approximately 1 foot per nanosecond (billionth of a second). If you only measure within a nanosecond, you only have 30 cm accuracy. They’re looking for about half a centimeter or so — “width of a pencil”.

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