Cryosat Agrees With PIPS

Cryosat delivered their first map – showing Jan-Feb 2011 ice thickness in metres.

For the past two years I have been getting constant flak from alarmists for using Navy PIPS2 maps. Turns out PIPS2 is very accurate. However, they seem to have been taken offline as of May 23.

Walt Meier wrote this on WUWT

PIPS vs. PIOMAS revisited

There was a lot of discussion earlier this year on the PIPS model sea ice fields vs. the PIOMAS model fields (e.g., here). At the beginning of the melt season, PIPS showed quite a bit of thick (3-4 m) ice throughout much of the Arctic Ocean, which wouldn’t be expected to melt completely. This portended less loss of ice during the summer. However, the PIPS fields did not agree well with the ice age fields, which showed less thick ice and a more dispersed multiyear ice cover. As it turned out, I think the PIPS were indeed to too thick, resulting in a forecast that was too high.

On the other hand, the PIOMAS total volume anomaly estimates were quite low going into the summer, indicating thinner ice and suggesting a low extent was likely. As I said previously, the volume seemed to me to be too low. Indeed, the PIOMAS forecast was lower than the actual minimum, though in the end it didn’t do a half-bad job in its prediction (4.7 predicted vs. 4.9 actual, in millions of sq km). To be sure, some of this could be attributed to luck, because there is always the wildcard of what the weather will do over the summer. Regardless, it is clear from the ice age, other ice thickness observations, and the overall state of the ice cover that volume is at or near record lows compared to at least the past 30 years. So while PIOMAS may be biased too low on ice volume, it captures the overall thinning trend and seems to better represent the actual state of the ice cover than PIPS.

h/t to Marc Morano

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31 Responses to Cryosat Agrees With PIPS

  1. Scott says:

    I don’t have much time to look into this stuff…how does the volume calculation from Cryosat 2 agree with the volume estimate from PIOMAS?

    Honestly, I was pleasantly surprised to see thicker (4+ m) ice near the north pole. Even PILS wasn’t that optimistic.

    It’s too bad the color schemes for the two plots don’t match – could you use your image-processing skillz to make them more easily comparable?


    • suyts says:

      Well, the color schemes aren’t exactly a match, but they’re pretty close. Red=red and light purple = light purple.

    • Paul H says:

      I think the comment about PIOMAS related to last years’s minimum extent results which Walt used to prove that PIOMAS was somehow valid.

  2. Julienne Stroeve says:

    I am very curious about the results for Baffin Bay. Seems 3m is a bit too thick for first-year ice in that region, especially after looking at MODIS imagery from March that shows very little slabbing and compacting that would increase the thickness. Same is true for other regions of FYI.

    • Scott says:

      PIPS actually agrees with your above statement it seems.

      As with any new instrument, I’m sure it takes a while to get all the data interpretation kinks worked out. Also, Julienne, being at NSIDC, have you had access to some of the data or at least the preliminary results from Cryosat 2?


      • Julienne Stroeve says:

        no, this is the first map I’ve seen of Cryosat sea ice thickness and I’m not sure how they handled the snow cover in generating it (which may be contributing to thicker ice measurements than we would expect for first-year ice). I’m sure we’ll know more soon.

      • Scott says:

        Hi Dr. Stroeve,

        Thanks for responding. It’s always nice to hear from someone who studies this for a living. Indeed, working out the kinks in new measurements is typically difficult and time consuming. I think you’re right that we’ll know much more soon. I imagine you’re salivating over the thought of seeing some of those results.


  3. Mike Davis says:

    Time to don your bathing suit and check out the tropical beaches in that region of the globe!

  4. Ill wind blowing says:

    The BBC article on Cryosat links to this other BBC article:

    As soon as Cryosat gives us 2 maybe 3 years worth of data; it will become obvious that:

    1. Reality is reality. That’s another way of saying “Death Spiral”.

    2. Another chapter will be written in the Socialist/Marxist/Communist/Fascist conspiracy theory. Perhaps we’ll be reading in WUWT that the forces of evil projected a beam of N rays towards Cryosat in order to garble their measurements. 😉

    • Scott says:

      Ill wind blowing says:
      June 21, 2011 at 7:12 pm

      As soon as Cryosat gives us 2 maybe 3 years worth of data; it will become obvious that…

      And this is my biggest problem with some people working in the climate field today. They prepare their conclusions before the data arrives. How acceptable is that?


      • P.J. says:

        “They prepare their conclusions before the data arrives”

        Thank-you for saying that. As someone who teaches science for a living, this is the one thing that bothers me more than any other about people in ANY field of science (climate or otherwise). Scientific investigations are supposed to answer a question, not prove a point. If your mind is made up before the experiment begins, the experiment is a waste of time as it is too easy to alter the parameters of the experiment in order to get the results you expect or want.

      • Scott says:

        P.J. says:
        June 22, 2011 at 12:01 am

        PJ, I agree with your comment. Please keep in mind that this is not everyone in the sciences, though the percentage does seem to be on the increase (personal anecdotal observation…take it as you will). Also, the tendency for this to happen seems to related to the social, economic, political, and/or theological implications of the study.

        Sometimes people try to label this tendency as biasing in science, but keep in mind that science is inherently biased. To make a good hypothesis, I have to have a hunch and then test it out. And yes, I often spend more time than I should on the hunch if it doesn’t pan out…biased. However, I work in operational science where I can repeat an experiment multiple times and even with slight variations to help evaluate a hypothesis. This is not the case in historical or observational science, so the incoming bias of the scientist can have a larger effect on the results (ideally no, but in reality, yes.)

        From what I’ve seen, there are two quite different yet very good evaluators of one’s work. The first is the expert in the area – they know the nuances and have insight and ideas that no one else can contribute. That’s why I like to see Dr. Stroeve’s comments here. In my own area, I know this to be true, as I can read a freshly published article in my field and catch errors, nuances in the data the authors seemed to miss (often with interesting implications that lead to my own hypotheses!), and oversimplifications designed to make the journal product more readable. Typically, modern science seems to do a good job with accruing these sorts of people and having them evaluate peers. However, the second group of evaluators is totally different. That group consists of intelligent and knowledgeable scientists/engineers OUTSIDE the specific area of science of interest. These people are good for catching very large issues that are outside of one’s microscopic focus when doing the research. Such errors can be common (but sometimes unfounded!) assumptions made by nearly everyone in the field, repeated methodology that has inherent problems but is used over and over again, and the lack of understanding of proper stats, electronics, etc. In my experience, current science does a very poor job of incorporating this type of evaluation, thus potentially allowing for very large systematic errors to propagate through a whole field (not saying that has ever happened, but there’s always the possibility).

        There’s really no easy way around these issues. One just has to be their own strictest critic, but that’s easier said than done.

        Just my thoughts,


      • P.J. says:

        Scott – thanks for your thoughts … lots for me to ponder here 🙂 . One scientist I am particularly impressed with in the climate debate is Henrik Svensmark. His documentary, “The Cloud Mystery” was one I really appreciated (I show it to my students). He said something to the effect that, “it isn’t enough to have a good correlation; you need experiments to test it”. Unlike so many in climate science who run computer models, he ran laboratory experiments. It took him years to build the lab, get the funding, run the experiments and process the data. It then took him 16 months to get published; some of the reasons certain journals turned him down was his work was “too long” or “not interesting enough”, yet they didn’t (couldn’t?) find anything wrong with his methodology or results. He was also accused of being irresponsible by some in the climate field because he dared to present a theory that was contrary to the CO2 orthodoxy. Much of what he discovered was by chance and good ol’ scientific curiosity. IMHO Svensmark epitomizes the way science should be done.

  5. Ill wind blowing says:

    Oh my; look at this interesting diagram from the very article that was posted on this thread.

    Notice how the average winter thickness is represented? Only 8’4″. It used to be 10′ in the summer only 30 years ago.

    • Scott says:

      Cryosat 2 was up 30 years ago? While I certainly agree that the ice was previously thicker, I don’t think a direct quantitative comparison can be made between measuring techniques, particularly spaced apart that far in time. And your link gave the average thickness as 8′ 2″, so please check your conversions.

      Also, what was the average winter thickness 30 years ago according to your source? Is the average thickness greater in the winter or summer? With all the transient winter ice that is much thinner, I’d be curious to know. Maybe Dr. Stroeve can enlighten us?


      • Julienne Stroeve says:

        Scott, this page shows two figures of sea ice thickness from submarine sonar and from ICESat, with sub observations starting in 1958. From this figure you can see how much the ice has thinned the past few decades.
        Thickness tends to be greater in winter than summer, though locally ridging/rafting events can change that.

    • Scott says:


      I asked how summer ice thickness compared to winter ice thickness (because you compared them unadjusted, making it out like the old average summer [bolded by you] thickness being higher than the current average winter thickness was shockingly bad). I’d hoped you’d be able to enlighten the people here on the facts when asked about them. That was only a few hours ago, and normally I’d wait longer for a person to respond (although a knowledgable person in this area would likely be able to answer immediately). However, given that you’ve had the time to write several snarky comments on both this thread and others, I think that indicates that you could’ve answered my inquiry if you wished to.

      Because you haven’t, how about I do instead? Take a look at this paper that looks at data from 1960-1982:
      Average ice thickness is highest in summer. For actual numbers, here are the four seasons (provided for those who don’t have access past the paywall, numbers are average thickness in meters +/- 1 std dev)
      Spring = 2.4 +/- 1.4
      Summer = 3.3 +/- 1.7
      Autumn = 3.0 +/- 1.9
      Winter = 2.8 +/- 1.8

      So if the summer is on average 3.3/2.8 times higher than winter, then how does that compare here? Well, we’d expect an average summer thickness this year of 9′ 8″…not too bad relative to the 10′ you mention here (I actually thought it would be a considerably larger difference). Now…I’d say that comparison is NOT the way to do it, but you were the one comparing summer and winter. Instead, I’d say that a direct comparison between seasons is more applicable, and Cryosat 2 measured 2.5 m vs the 2.8 m given in the discussed paper. I don’t think that drop is significant considering the uncertainty of the old measurements as well as the differences in methodology.

      All that said, I do agree we’ve seen a considerable loss of ice over the last 30 years. But that’s no reason to make completely invalid comparisons to try to make your point.


      • Julienne Stroeve says:

        Scott, quick comment. While it’s true that if you take mean sea ice thickness of the Arctic Ocean, the mean is likely larger in summer than in winter because you have removed a lot of the thin ice through melt, if you look at the spatial distribution of ice thickness you will see thinning of the multiyear ice in summer. ICESat thickness maps produced by Ron Kwok at JPL show this nicely. I agree that it’s best to compare thickness retrievals from the same time of year (i.e. at the winter maximum each year, or at the summer minimum each year).

  6. Ill wind blowing says:

    Maybe everyone on this thread should get together and buy or rent a yacht to start taking cruises through the Arctic in the years to come. Or maybe you can head straight into Santa Claus territory (N.P.). If your yacht is big enough and you take it slowly you might be able to plow through some 1 foot thick rotten ice on your way to elfland. 😉 🙂 😮

  7. Ill wind blowing says:

    So tell me Steve; where is this going? Where is the predicting power of skeptic science. What, roughly speaking, is the situation going to be by 2020. You could be off by a bit. Just tell us; will the Arctic ice cap grow in extent and or thicken or will it go the way AGWs have been predicting.

    From what I’ve previously read here and on WUWT it doesn’t seem to matter what will happen in the long run. So much for predicting power. It seems that the only thing that Skeptics know for sure is that whatever happens depends on automatically taking the opposite stand that AGWs do.

    • I think that sea ice will either increase, decrease, or stay the same.

      • Ill wind blowing says:

        I think that sea ice will either increase, decrease, or stay the same.

        I’ll assume that you’re being serious. What’s not serious is how AGWs are accused of covering all possibilities but skeptics can get away with it.

        In any case, my point about predicting power, or lack thereof, has been made. Skepticism predicts nothing of any substance, it merely looks forward to taking a diametrically opposed view of whatever Climatologists say.

        Here’s my prediction which is as easy as predicting that it will rain in my neighborhood sometime next year.

        Official prediction:

        Time range 2020-2030.
        Ice free Arctic, in the summer, for a few days initially; extending to weeks and months in subsequent years. This will exclude a band of ice over colder shallow waters north of Alaska, Canada and Greenland.

        Quite a few are predicting somewhat earlier dates. My prediction based on the above parameters: 2018-2022.

        Some have foolishly asked me what “hard evidence” I based my predictions on. My answer is: “Before you even try to figure out anything you need a lack of prejudice and a ton of humility.” As soon as you get ot that point, you’ll be half way to figuring out the answer for yourselves.

    • suyts says:

      Or, maybe that what alarmists do….. take the opposite position that skeptics do.

      It really isn’t an opposite view to state, “It is not.”, to a person screaming the sky is falling.

  8. Neven says:

    Any idea when PIPS will be back and why it’s off-line? It wasn’t last year around this time.

  9. Gary Mount says:

    “If your mind is made up before the experiment begins…”

    In the Michelson-Morley “Detecting The Ether Wind Experiment”, they set up an experiment to detect the ether wind. The unexpected results is said to have greatly advanced science. In 1927, a claim was made by a “scientist” that he had conducted an experiment that detected the either wind. This is long after Einsteins theory was published, kinda relative with today’s claims about climate change.

  10. 4billion says:

    Cryosat’s minimal thickness is 2 meters, so it shows the Arctic to be a lot thicker than PIPS2, probably to cover up just how little is left.

  11. Rob Dekker says:

    Steven Goddard : it may be too late to reduce your excitement about ‘consistency’ between Cryophere’s first map and PIPS or consistency between both these reports and the real world.

    To spoil the fun : It seems that both are heavily biased towards excessive ice volume.

    For one, as Dr. Stroeve points out on WUWT : the Cryosphere map has been validated with only two measurements, both in multi-year ice, none in first-year ice. Besides, they seemed to have interpreted snow cover as solid ice.

    And PIPS was taken offline for a reason :

    Since late April/early May 2011, PIPS 2.0 has developed an unrealistic opening in the North Pole region. On 22 May 2011, PIPS 2.0 stopped running because of a numerical instability. Since that time, we have been carefully trying to diagnose this problem (checking for anomalous atmospheric forcing, initial fields, boundary conditions, assimilated satellite ice fields, etc). During this process, the system’s ocean model time step was reduced and the system is currently running again. The unobserved opening near the North Pole is still present and can be seen in the ice concentration and ice thickness fields. PLEASE USE THESE FIELDS WITH CAUTION! We have subsequently filled in the period from October 2010 to present with the hindcast using the reduced ocean model time step. Because PIPS 2.0 is a legacy system and will soon be replaced with a new ice nowcast/forecast system (see below), little additional effort will be expended to keep it running.

    In short, PIPS will be replaced with a much more updated system. Most of us ice watchers are looking forward to the new system, which you can observe in action (with animations and all) here :

    I hope that this new system (the Arctic Cap Nowcast/Forecast System (ACNFS)) will be more accurate than PIPS 2.0, considering that on multiple occasions it reported 4 meter ice where open ocean was clearly visible from MODIS pictures, and in general (despite it’s popularity here on WUWT) seemed to be out of touch with reality. For confirmation of this observation, consider that currently sea ice extent (both in the Actic as well as globally) is breaking all time record lows, and shows no slowdown in breaking the minimium extent record (of 2007).

    If you want to see a picture of what really goes on in the Arctic right now, then check this out (latest picture taken at the North Pole) :

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