By Steven Goddard
There have been a number of inaccurate claims made by commentors about Navy PIPS2 ice thickness maps. These claims have been along the lines of :
- PIPS isn’t used by the Navy any more, because it isn’t accurate enough
- PIPS maps over-represent ice because they don’t see areas of open water
- PIPS maps don’t take into account ice concentration. They consider the ice to be 100% concentrated
- PIPS is just a model. It isn’t an accurate representation of the ice.
The US Navy clearly refutes these claims –
04/06/2010 – Pamela Posey
The Polar Ice Prediction System (PIPS 2.0) is the current U.S. Navy’s operational ice forecasting system.
PIPS 2.0 forecasts ice conditions in the northern hemisphere with a horizontal grid resolution ranging from 17-33 km depending on the grid location. The system couples the Hibler ice model to the Cox ocean model and exchanges information by interfacing the top level of the ocean model with the ice model. Ice concentration fields derived from the Special Sensor Microwave/Imager (SSM/I) are assimilated into the PIPS 2.0 system along the ice edge. The system produces a 120-hour forecast of ice fields which are sent to the National Ice Center (NIC) to be used in their daily ice forecasts.
The Navy also refutes the claims that they don’t correct for concentration :
The model-derived ice thickness field and the ocean surface temperature field are then adjusted to be consistent with the concentration data.
These models are required to go through rigorous validation studies to prove their capability to produce accurate short term variability. Data assimilation plays a major role in the accuracy of these forecasts. Once operational, continuous quality control and evaluation of the products may be used to upgrade the system and improve forecast accuracy.
The video below for June 10, 2010 shows that PIPS maps accurately reproduce current ice conditions. It overlays the UIUC ice concentration map on the PIPS map.
Map sources :
http://arctic.atmos.uiuc.edu/cryosphere/NEWIMAGES/arctic.seaice.color.000.png
http://www7320.nrlssc.navy.mil/pips2/archive/pips2_thick/2010/pips2_thick.2010061100.gif
As you can see, areas of open water are shown as open water, and areas of low concentration also have lower thicknesses. The incorrect claims repeated over and over and over again by FUDsters just don’t hold any water.
PIPS2 is not perfect. Here is what the Navy says :
A recent study by a group of scientists from the NIC and NOAA (Van Woert et al., 2001), showed that although the PIPS 2.0 forecasts (48-hour) were better than persistence on average, there were still substantial biases in its prediction of the growth and decay of sea ice in the marginal ice zone. PIPS 2.0 often over-pre- dicts the amount of ice in the Barents Sea and therefore often places the ice edge too far south. In contrast, PIPS 2.0 often under-predicts the ice extent in the Labrador Sea and Hudson Bay.
This doesn’t affect my calculations, because I am only measuring regions which normally contain significant amounts of late summer ice. Also, my comparisons are relative year over year comparisons. The absolute values of ice thickness are not important to my conclusions.
Conclusion : PIPS2 maps is the best available and are used by the US Navy. They are quite accurate and they do account for ice concentration. No doubt, some commentors will continue to ignore the facts, and post instead what suits their agenda.
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“and post instead what suits their agenda.”
That pretty much fits the pattern. It doesn’t matter what data you find, the arm waivers will go to any extreme in an attempt to invalidate it. The only “valid” data are data that show warming. At this point I have not yet found anyone to produce data that shows that recent warming is in any way unique or even unusual yet they continue to tell school children that the planet needs to be “saved”.
It is just crazy.
Does this mean they use continous update of the “model” from real life measurement, like e.g. using a kalman filter or similar? In that case I think I one could say they estimate the values between updates. Is this correct?
That is totally different from the so called “climate models” which is supposed to run “Dead Reckoning” for decades int the future.
If the Navy ‘gets by’ using this system, lives depend on it, and therefore it’s probably pretty good for practical applications. A sub can’t surface if the ice is too thick and even icebreakers must have limits.
No doubt, some commentors will continue to ignore the facts, and post instead what suits their agenda.
This should be a thread where those particular commentors will go on and on about PIOMAS.
But here’s some more facts from Cryosphere Today:
June 11, 2008 compared to June 11, 2010, shows higher concentration in 2010:
http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=06&fd=11&fy=2008&sm=06&sd=11&sy=2010
The PIOMAS graph says this has not happened. It shows there has been ice loss compared to 2008:
http://climateinsiders.files.wordpress.com/2010/06/bpiomasicevolumeanomalycurrent.png?w=510&h=367
The PIOMAS graph is wrong.
Definitive statements.
But from an earlier criticism, I understand that the PIP data was going to get washed out and only the (AGW-motivated) PIOMASS computer model was going to get funded. Is that true? It would mean there is no “second check” of ice mass – a critical argument (maybe the only argument left) supporting the politics of AGW hysteria.
Poor old trolls.
Wrong again!
Worse than we thought.
Yes, the Navy is relying upon it for ice forecasts, so it has value.
Otherwise, we’d have yearly ship sinking and sub accident statistics to talk about.
We do have the Canadians out rescuing would-be NW Passage afficiandos who aren’t paying attention to the real world.
All despite repeated warnings that the disappearing Arctic Ice is hype.
Amino Acids in Meteorites says:
June 12, 2010 at 10:58 am
Bottom line: PIPS2.0, don’t leave home without it.
PIOMASS: caveat emptor.
Steve,
A very reasoned and straight forward presentation. I still strongly disagree with your final conclusion:
“PIPS2 maps is the best available and are used by the US Navy.”
I think in interesting that you quote Ms. Posey, who undoubtedly has a great knowledge of both PIPS 2.0 and 3.0, for she wrote the training manual on PIPS 3.0 back in 2007-2008, a link of which is given below.
Do you honestly believe that the Navy is going to release it’s very best technology and sea ice prediction system on a public web page the requires Internet Explorer 4.0 at 800 by 600 resolution for viewing? Especially in light of the increasing military, economic, and strategic interest in the Arctic?
I do not know why PIPS 3.0 is not fully available to the public, though I can suspect the reasons. But let’s take a look, once more, at a few strong suggestions and hints that PIPS 2.0 has been pretty much left in the dust for the newer version 3.0, which incorporates the CICE Los Alamos model combined with HYCOM. First, take a look at a quote from Ms. Posey from this document:
http://www.nrl.navy.mil/content_images/09_Ocean_Posey.pdf
Where she says:
“PIPS 3.0 is now producing daily 48 forecasts at the Naval Oceanographic Office (NAVOCEANO) and will have completed its validation tests by mid-2009.”
But more telling is the actual PIPS 3.0 user manual, available at this link (this is the unclassified version of the user manual by the way):
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA489794&Location=U2&doc=GetTRDoc.pdf
Please pay special attention to page 33 of 86 of this manual, where a very nice map is supplied showing us a PIPS 3.0 Arctic Sea Ice concentration map for March 15, 2008. Comparing this map to a PIPS 2.0 map from the same date yields a treasure trove of interesting points of differences between the much improved PIPS 3.0 versus PIPS 2.0. We see the far greater fidelity and resolution of the PIPS 3.0 map over the PIPS 2.0. I dare you Steve to do one of your lovely animations popping back and forthe between this March 15, 2008 PIPS 2.0 concentration map:
http://www7320.nrlssc.navy.mil/pips2/archive/retrievepic.html?filetype=Concentration&year=2008&month=3&day=15
And and the map shown on page 33 of 86 of the PIPS 3.0 training manual. You’ll instantly see the greater resolution of the PIPS 3.0. But even better, go to page 34 of 86 of the PIPS 3.0 user manual and look at the thickness data, and compare to the PIPS 2.0 model thickness for the same data. Big difference. At least you were honest to state clearly in your post the known deficiences with PIPS 2.0. I think this kind of inaccuracy in a model that is a decade old would be intolerable to the Navy. Hence the reason they needed a PIPS 3.0
It is true, I do not have the neatly (and I would say intentionally well packaged) statement like you have for PIPS 2.0, saying that PIPS 3.0 is now the standard used by the Navy. I only have the circumstantial evidence such as the statement by Ms. Posey in the link above, that leads me to believe that the Navy is using PIPS 3.0, but just not ready to released a down-scaled model yet on a nice little web page for public consumption. We’ve got to to believe that our military is smart enough to keep it’s best information private and classified.
I think the procedure of using the PIPS 2.0 model information to compare sea ice thickness and change year to year is brilliant, I just think, that the data you’re using is not accurate (as shown for example by comparing it to the PIPS 3.0 data). I’ve actually emailed Ms. Posey to get some clarification on the status of PIPS 2.0 and 3.0, though I really didn’t expect to hear from her, as I’m sure she has some level of security clearance, and she probably couldn’t tell me much about the PIPS 3.0/CICE/HYCOM status as it has not been officially cleared for publilc consumption yet, though we know from the link I gave above, that NAVOCEANO is certainly using it on a daily basis, as stated by Ms. Posey herself.
Since we can’t have access to the better PIPS 3.0 data, I choose to rely on PIOMAS over PIPS 2.0, as it also uses the CICE model like PIPS 3.0, and it’s a vast improvment over PIPS 2.0. PIOMAS has shown a great deal of volume continues to be lost from Arctic sea ice, and I think the rapid melt so far this year is tending to show that to be true.
So as late as April of this year (or is that in fact June 4 instead of April 6?), Pamela Posey of the US Navy Naval Research Lab confirms in public presentation at a scholarly conference that PIPS 2.0 is the “current” version. Gee, what happened to PIPS 3.0 that we were assured had superceded PIPS 2.0 years and years ago?
Someone write to the producers of Deadliest Catch and have them ask the crab boat skippers what they think of the quality of ice forecasts and whether it seems to them if the arctic climate has changed over the decades.
@Amino Acids:
The Cryosphere Today comparison include the warning that “sea ice concentrations less than 30% are not displayed in these images.”
When you’re comparing the PIOMAS curve, which doesn’t throw data out, with the Cryosphere Today side-by-side images, which do throw data out, why do you choose to pick the one that trashes data?
Exactly!
When things were bad PIPs reported it so it’s good today as far as I’m concerned.
Here is a Yearly volume comparison image
Steve Keohane says:
June 12, 2010 at 10:23 am
I doubt any sub commander would rely on anything other than his own readings of the ice thickness above him before surfacing.
Perhaps just go back to extent or area like the good old days so we don’t have this constant argument?
Andy
1. You do NOT use pips’ volume because they do not calculate it.
2. You do a Volume on the center one-tenth of the Ice “the Central Basin”
– – in 2007, winds blew ice INTO the central Basin
3. We are not charging pips does not INCLUDE Concentration – –
– – Pips includes NO Thickness data, from Subs, ship, planes or satellites.
As I have quoted before, the explanatory pdf says it is “initialized” with concentration.
– – The Arctic’s AVERAGE THICKNESS is ASSUMED — from the previous year, less the usual AGW decline.
>But all this is unimportant.
Science has to Check with REALITY.
Piomas underestimated the 2007 loss as 3000 cubic Kilometers — Icesat put it at a 4000 cubic kilometer loss (leaving 6000 in October-November, the Satelite did not operate at the September minimum
http://psc.apl.washington.edu/ArcticSeaiceVolume/images/IceVolAnomaly19792010.MarNov2.png – – compares Piomas to Icesat.
whereas the “Central Basin Piomas” Steve relies on put the loss at
0.3 x 10E9 km3 — leaving 0.49
That’s right:
http://www.nrl.navy.mil/content_images/09_Ocean_Posey.pdf
is Steve’s source (Thank you: Gniess) .
It had a 6% drop for 2006-yo-2007 — off by a FACTOR OF SIX
>>>>> SIX ! ! !
(not to mention that Either this means the “Central Arctic” is a 1/10,000 th of the Arctic Ocean OR there more likely Posey has a typo — seems to be a mix: 1/10th the Basin, is the study area & Posey should have used 10E12 cubic meters ie, a thousand times more than his 10E9.
That is: Central Basin Pips Volume, from Posey:
Sep 2006 = .52 x 10E9 cu. meters (E = “exponent” = number of zeros)
Sep 2007 = .49
Sep 2008 = .38
Piomas has a 30% drop, 75% of the REAL LOSS.
… Icesat’s coverage, over 2 months, is very comprehensive and actually measures THICKNESS.
Piomas has spotty observations & bridges the gaps with Concentration using the OBSERVED thicknesses ( which is why late 2007 was the ONLY data-point where Piomas & ICESAT were not a near-perfect MATCH — only in mid 2008-May2010 between Satellites, were there regular flights over the central Area which only melted in 2007 — so Piomas missed that. Ironically, “Central-only” Pips did even WORSE there, because the Winds of 2007’s El Nino — similar to This year’s MORE powerful El Nino — were pushing the Ice together making it APPEAR thicker. I.E. Zero Open Water = 100% concentration)
Pips is Concentration ONLY — giving RELATIVE thickness.
It is for guiding Icebreakers to the thinner Ice.
That it does well & updates almost daily whereas ICESAT would tell you TWO MONTHS LATE & Piomas updates at best 3-5 days – – & lately every other Update has to add 2 weeks because it drops off the chart & they have to reload a new one.
Icebreaker’d be sunk by then: winds blow the ice here, there, on an almost Daily Basis.
You forget what Pips is FOR .
(PS Piomas was set up by 8 different Researchers who disagree a lot, so they could contrast their DIFFERING Predictions — which is why it shows less bias — it is just a “plug in your Poison” framework – – in fact, with the LESSER melt in Sep 2007, it showed an ANTI-AGW bias)
Moderator, please delate my duplicate posts!!!
Reply: Actually I left them as a lesson. Don’t do that. Sometimes things get stuck in the spam filter for a while. Learn to live with it. I will now clean up your mess. ~ ctm
I don’t care what models or data are put forth. Predicting what the climate/weather future 10 years, or 100 years, out is going to be is patently ridiculous folly. There are far too many unknown events that could occur to even think about it. The entire edifice rests on statistical/probabilistic assumptions about an inherently chaotic, unpredictable reality. Might as well read chicken bones.
By Steven Goddard, quote – “No doubt, some commentors will continue to ignore the facts, and post instead what suits their agenda.”
I must admit I do not understand your acrimonious ending remark. The commenters’ corner is for all of us – readers of the weblog – and a place where we can exchange _any_ views, the wrong ones too, without being spit in the face.
Your succinct post has explained a lot and what’s more, you put the info into kinda logical order. Hat tip to you for doing that, but the saber rattling at the end left a pinch of distaste. In my mouth at least.
My best regards
USA 1 – England 1
Altidore had a great opportunity for the US win, but hit it six inches too low.
First goal England has ever scored in the World Cup against the US. First goal the US has scored against England outside of the US since 1950. Great match!
04/06/2010 – Pamela Posey
The Polar Ice Prediction System (PIPS 2.0) is the current U.S. Navy’s operational ice forecasting system.
04/06/2010
04/06/2010
04/06/2010
04/06/2010
04/06/2010
04/06/2010
Steve, do you know where I, and anybody else here, could get the scale values assigned to colors in these PIPS 2.0 gif files? I assume these are invariant over the many years of collected gif files as they all seem the same.
There is more information on PIPS2.0 available in a paper by Posey and some other people here : http://www.nrl.navy.mil/content_images/09_Ocean_Posey.pdf
(“A Thinning Arctic Ice Cap as Simulated by the
Polar Ice Prediction System (PIPS): 2000–2008”).
They do actually compute minimal ice volume for the central arctic according to Pips for 2000-2008 (Except that there seems to be a mistake in the units stated?)
So, the bottom line is there is no accurate view of Arctic sea ice. Funny, that’s exactly what I’ve believed for a long time.
I find it somewhat humorous that this argument continues as to which bad model is better. It’s also interesting that those who believe in piomas, even after its failures over the last two years, would spend so much time defending it. What could possibly be their motivation? Why should they care? If they are right, then Steve will be proven wrong in a couple of months.
It’s already been proven several times over that Steve is not going to change his view. To me it reeks of desperation. So, why so desperate?
Przemysław
I have been trying to have an intelligent discussion about the data, but the signal to noise level in the discussion forum of the last few articles has been spectacularly low. A few people seem to be intentionally and repeatedly disrupting the discussion with misinformation.