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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wayne,
The PIPS scale is here
http://www7320.nrlssc.navy.mil/pips2/ithi.html
http://wattsupwiththat.com/2010/06/12/what-is-pips/#comment-408185
wayne says:
June 12, 2010 at 1:52 pm
Is this the answer you asked for?
http://www7320.nrlssc.navy.mil/pips2/ithi.html
Regards
I’ve been following the discussions concerning PIPs 2.0 for some time now and I am increasingly amazed by the pronouncements made by certain contributors who appear to live under bridges of the rickety-rackety variety.
Why on earth would the US Navy maintain up to date and provide access to 10 years of archives of PIPS 2.0 output if they had replaced it by PIPS 3.0.
See here for tomorrow’s forecast of ice concentration: http://www7320.nrlssc.navy.mil/pips2/icon.html
see here for tomorrow’s ice thickness forecast:
http://www7320.nrlssc.navy.mil/pips2/ithi.html
and here for tomorrow’s ice displacement:
http://www7320.nrlssc.navy.mil/pips2/idis.html
You can verify for yourselves that they have a continuous record by checking the archive:
http://www7320.nrlssc.navy.mil/pips2/archive/index.html
Now why, I wonder, would they go to all this trouble if they had a better system (V3.0) tucked away somewhere.
Oh, I know – they are doing it to fool Al Qaeda’s arctic submarine martyrs!
Software validation such as PIPS survived might be usefully applied to the climate models. Back in the days of the 10 MHz ‘286, I was a member of the ACM, and still have a couple huge binders of validated software routines. You don’t need validated, no-surprises routines to write a climate model, but when the models’ output is used to justify government action that will cripple world economies, it would be nice to have that checkbox ticked.
http://www7320.nrlssc.navy.mil/pips2/ithi.html
The Heaviest Ice is on the Russian Coast — yeah, over 5 meters ! What a DISPROOF of Pips as being accurate on Thickness.
It is from a Microwave Satelite’s data. Yopu just use it because picking a tiny section of the Arctic with an unusual method is the ONLY Contrary view !
Charles, you make an interesting point. The thickest ice this year is exactly where it disappeared in 2007. What do you thhink that bodes for 2010?
Steve Goddard wrote,
“PIPS maps don’t take into account ice concentration. They consider the ice to be 100% concentrated.”
Who claimed this? I’ve mentioned concentration a number of times, so maybe you’re referring to me — but I never said that PIPS maps don’t take account of concentration. They show a separate map just for ice concentration.
What I asked was whether *you* took account of concentration, in calculating volume estimates from (apparently) the thickness map alone. Is the answer just No, your calculation did not include concentration? Or Yes, it was part of the equation?
In either event, why not publish your numerical estimates? (My apologies if you did so and I missed it.)
Przemysław, that’s it, thanks.
geo says:
June 12, 2010 at 12:36 pm
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?
She also confirmed this:
“More recently, the Naval Research Laboratory (NRL) has performed sea ice hindcasts for the Arctic region derived from the latest coupled ice-ocean prediction system. The 1/12° Arctic Cap Nowcast/Forecast System (ACNFS) is based on the HYbrid Coordinate Ocean Model (HYCOM) coupled to the Los Alamos Community Ice CodE (CICE) and tested using the Navy Coupled Ocean Data Assimilation (NCODA). NCODA uses a three-dimensional variational (3DVAR) data assimilation scheme. The system assimilates surface observations from satellites (altimeter data, sea surface temperature (SST) and sea ice concentration) as well as in-situ SST’s and temperature/salinity profiles. The ACNFS has a horizontal resolution ranging from 3.5 km near to pole to approximately 6.5 km near 40°N. “
I keep hearing from some “commentators” here that the sea water absorbs so much more sun light than ice (possibly with a sheen of water at the surface). When I look into the sun with a maximum altilude of 23.5 degrees, I get blinded by the reflection from either water or ice. The sun is at a very shallow angle.
So how much more short wave energy is actually absorber by the sea water over and above by ice at that very low angle. Can IR be assumed to be almost totally absorbed by both? Anyone knowledgable in optics?
The only models that worth, according to the metric system are: 0.9 meters, 0.6 meters and 0.9 meters (this last size is hips´size).
Peter Plail said:
“Now why, I wonder, would they go to all this trouble if they had a better system (V3.0) tucked away somewhere.”
_________
I’ve provided ample reasons why, and your own common sense should tell you. Do you put your best charts and maps of an increasingly strategic area up on the internet? I’ve also provided ample links to the PIPS 3.0 manual and Ms. Posey’s own statement that NAVOCEANO is using PIPS 3.0 on a daily basis.
PIPS 3.0 and PIOMAS share a common model– CICE. It is the most refined and most developed sea ice model in the world and PIPS 2.0 can’t hold a candle to it.
For some of you who may doubt how serious the US is in maintaining military superiority of the Arctic (and why therefore, the Navy may not be quite ready to release some down-scaled version of PIPS 3.0 to the public) you may find of interest this Presidential Directive (NSPD-66) on the Arctic region, released just before President Bush left office in 2009:
http://www.fas.org/irp/offdocs/nspd/nspd-66.htm
Ahhh
So, a Canadian site’s abstract, which seems to imply the Navy is moving to something new. And what do they mean by “Ice concentration fields… are assimilated… along the ice edge”?
“better than persistence on average” – is really good?
In the video there seems to be serious problem north of the Bering Strait and NE of Greenland. And NE of Banks Island, and where the Kara and Barents join.
All the talk here and elsewhere about “PIPS must be good because the subs use it to surface…). uh, yeah. Well, it looks like they would be told not to surface anywhere near the pole. However, I bet they look at satellite images. And more than that, they use their upward-looking sonar to determine the ice thickness above (as the Skate did in 1959). They don’t determine whether to surface based on a large grid model of the ice.
Gneiss
PIPS corrects their thicknesses for ice concentration. I don’t know how to explain it any clearer.
stevengoddard says:
June 12, 2010 at 1:58 pm
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.
————————————————————————————
Gosh Steve! Maybe we’re actually skeptics! Maybe we’re presenting other evidence, questioning the suppositions, asking if the facts can be verified, wondering about alternative hypothesis.
I know, I know. What you really want is a slap on the back and an “atta boy, keep up the good work!” Well, soldier on…
R Gates:
You write as though you’re an insider, with a good-level security clearance. Perhaps you are.
But the rest of us amateurs, with an equal disdain for rickety models and bought-and-paid-for ‘science’, must make do with what Is publicly available.
Arguments to authority just don’t cut it with us. Unless you can publicly share that data, it’s unicorn milk and pixie dust.
Amino,
You say PIOMAS is wrong. Is PIPS 2 wrong as well in agreeing that that there has been quite a fall in ice volumes recently?
http://img811.imageshack.us/img811/5835/pipsvspiomas.png
Here’s the full PIPS dataset:
http://img810.imageshack.us/img810/949/pipsallb.png
Please note the PIPS data prior to 2002 is not directly comparable to later values.
“R. Gates says:
[…]
I’ve provided ample reasons why, and your own common sense should tell you. Do you put your best charts and maps of an increasingly strategic area up on the internet?”
This could also explain why GISS doesn’t publish the *real* temperatures… 😉
JK
Anyone who believes in the PIOMAS data must necessarily also believe that we are headed for a huge meltdown this summer. There are consequences for adhering to a flawed belief system.
Charles Wilson says:
June 12, 2010 at 2:40 pm
The Heaviest Ice is on the Russian Coast — yeah, over 5 meters ! What a DISPROOF of Pips as being accurate on Thickness.
Um, why?
Is there some sound reason why the ice around a few spots at the top of Russia (and Greenland) can’t be the thickest?
crosspatch says @ur momisugly June 12, 2010 at 10:12 am:
…the arm waivers…
Do you have to sign the arm waivers with your feet? 😉
Wayne Findley said:
“Arguments to authority just don’t cut it with us.”
__________________________
Wayne, I simply quoted the same expert as Steve did (Ms. Pamela Posey) citing both the PIPS 3.0 manual that she wrote plus her statement about PIPS 3.0 being used every day at NAVOCEANO.
An even broader question ought to occur to even the most skeptical of minds: Why would the Navy be using PIPS 3.0 at NAVOCEANO if PIPS 2.0 was accurate? The take away from all of this simply should be to question the accuracy of PIPS 2.0, especially when basing such statements as a 25% increase in Arctic sea ice volume since 2008 based on this suspect model data .
R. Gates,
Perhaps you need to consider the fact that the DoD has a lot of newer tech systems in development but are not ready for prime time due to serious flaws and errors in their behavior. Perhaps while the Navy is DEVELOPING PIPS 3.0, it has not yet been deemed to be ready for navigational use and they continue to rely on the MORE RELIABLE PIPS 2.0 until it is ready to supplant 2.0.
R. Gates
So what you are saying is that University of Washington PIOMAS profs have access to super-accurate / super-secret spy ice data, and that their graphs showing a record negative anomaly are dead-on accurate.
I’ll put you down then as forecasting a spectacular meltdown this summer.