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.
Maud Kipz,
Cryosphere Today ‘trashes data’?
Przemysław Pawełczyk says:
being spit in the face…saber rattling
That is exaggeration.
I think it would be better if you go to RealClimate and watch how they treat any commentor that doesn’t agree with their agenda. Then come back here and you’ll find quite a bit of patience and tolerance.
And Steven Goddard is right, there are commentors who are ignoring everything when it comes to Arctic ice but the PIOMAS graph—and I mean everything! No matter how reputable the data is they are trying to find ways to make it look useless while they take a lone source, which a climate model at that, and call it the only valid source, literally, the only valid source.
You must have noticed that in these Arctic ice threads?
Richard M says:
June 12, 2010 at 1:54 pm
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?
That’s pretty telling, isn’t it, that they are defending it so much.
The reason is is that the PIOMAS graph claims that Arctic ice continues to decrease since 2008. But real data shows it is increasing.
They have nothing else left if PIOMAS is wrong.
That’s why the gang’s all here trying to discredit Steven Goddard, to discredit Cryosphere Today, to discredit PIPS, and anyone and anything else that shows or says Arctic ice has increased since 2008.
There are new commentors here from other blogs that are reading at those blogs about WUWT and Steven Goddard posting on Arctic ice and showing how the PIOMAS graph is wrong.
So they’re here circling the wagons.
Peter Plail says:
June 12, 2010 at 2:13 pm
Oh, I know – they are doing it to fool Al Qaeda’s arctic submarine martyrs!
ROFL!
Speaking of things not looking quite right- zooming in on http://ice-map.appspot.com/ north of Greenland is supposedly where all the thick multi-year ice is accumulating, but it sure looks full of crack and holes, so I dunno…
“There are consequences for adhering to a flawed belief system.” Hmm, I’m tryin’ to figure out exactly where that’s goin’.
the trolls are here, wagons circled, both barrels, full throat, white knuckling,
all the while the average person is out on a Saturday at the movies, or out to eat, or with friends, or watching tv, ……..and not worrying about global warming:
http://people-press.org/reports/images/584-1.gif
It’s them long, cold winters that’s making people forget about that Al Gore movie
I nominate this kid for Barak Obama’s new climate czar, ;-):
stevengoddard says:
June 12, 2010 at 8:24 pm
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
__________________
Nope, Dr. Zhang and his associates simply use the most advanced sea ice model set in the world, know as CICE. The Navy combines it with the HYCOM product to get their PIPS 3.0 model, and Dr. Zhang uses it in a different way to get the PIOMAS model. Both models are far more advanced than PIPS 2.0 which does not use CICE.
And I’ve got no problem at all sticking with my March prediction of 4.5 million sq. km. summer minimum, and it was nice to see PIOMAS now giving a similar number at 4.7 million sq. km. Both are close enough to each other and lower than 2008/2009 but not quite at the 2007 level. (all based on IJIS/JAXA data of course)
BTW, didn’t you want to take up my challange do your fancy little animation flippy thing going back and forth between the March 15, 2008 PIPS 3.0 and March 15, 2008 PIPS 2.0 just so everyone can get a nice direct appreciation for the differences?
stevengoddard says:
June 12, 2010 at 8:24 pm
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.
OMG, this one’s funny too!
JK
You are looking at the land surface north of the Greenland Ice Sheet.
R. Gates
PIOMAS is showing an anomaly nearly 50% larger than this date in 2007. Everyone including Joe Bastardi is forecasting a warm summer for the Arctic. How could we not set a record minimum under those conditions? Please explain.
Mooloo says:
June 12, 2010 at 6:37 pm
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?
Because all the other evidence (not models) shows that it isn’t, of the thick ice patches (~5m) shown on the current PIPS forecast touted here by Steve at least three of them are clearly not thick ice (see the circled regions below), one of them is even open water (N Greenland):
http://i302.photobucket.com/albums/nn107/Sprintstar400/arctic_AMSRE_nic-1.jpg
According to Steve “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.”
Clearly not true!
Also according to Steve:
“The video below for June 10, 2010 shows that PIPS maps accurately reproduce current ice conditions.”
Really?
In fact this appears to be a common problem with the PIPS model and they have a procedure for dealing with it:
“if the SSM/I data indicate there is no ice where the model
had produced ice, ice is removed from the model field
and the ocean temperature is raised one degree above
freezing to restrict immediate ice growth in this location.”
Obviously that wasn’t done in this case!
Also:
“Although PIPS 2.0 can predict
large-scale polynyas, it does not have the capability
to produce smaller polynyas or leads or to provide
guidance on lead orientation.”
I guess not.
Also note the following:
“The SSM/I brightness
temperatures are converted into ice concentration
data using the Navy CAL/VAL algorithm (Hollinger et
al., 1991) at FNMOC. This algorithm is sensitive to the
ice/water boundary and to thin ice. As such it provides
a good estimate of the location of the ice edge and a
better estimate of thin ice than most other algorithms.
However, due to its sensitivity to thin ice, it often saturates
too quickly to 100% ice concentration, producing
an overestimate of high ice concentrations.”
My emphasis.
Amino Acids in Meteorites says:
June 12, 2010 at 8:35 pm
And Steven Goddard is right, there are commentors who are ignoring everything when it comes to Arctic ice but the PIOMAS graph—and I mean everything! No matter how reputable the data is they are trying to find ways to make it look useless while they take a lone source, which a climate model at that, and call it the only valid source, literally, the only valid source.
Don’t you mean Steve Goddard who is ignoring everything but the PIPS model and continues to churn out his faulty calculations based on it and steadfastly ignores any suggestions to produce a calibration calculation to validate his method? The Steve Goddard who rubbishes the PIOMAS model which has actually been calibrated against the satellite measurements of thickness.
stevengoddard says:
June 12, 2010 at 5:50 pm
Gneiss
PIPS corrects their thicknesses for ice concentration. I don’t know how to explain it any clearer.
Pamela Posey does, what they do is if they predict ice where none is observed they remove it, if they predict no ice where ice is observed they add some thin ice (0.3-0.6m). Other than that they do nothing.
I’m surprised at this constant exchange about PIPS2.0. Steve, why don’t you take the years of ICESat thickness values and compare them with the PIPS2.0 values so you can either prove or disprove that PIPS2.0 gives an accurate representation of the interannual variability in the ice thickness (and the seasonal variability). We know the absolute values are wrong (PIPS2.0 shows too thick of ice), but at least compare the spatial, seasonal and interannual variation. At least the authors of PIOMASS did do that for a few years. I believe you can simply take Ron Kwoks published values and do your own comparison with PIPS2.0.
Then we can finally move on to another topic of discussion.
stevengoddard says:
June 12, 2010 at 9:51 pm
JK
You are looking at the land surface north of the Greenland Ice Sheet.
No he isn’t, he’s looking at the mess of fragmented ice and leads north of Greenland (see about 2/3rds down)
http://rapidfire.sci.gsfc.nasa.gov/realtime/single.php?2010163/crefl1_143.A2010163233500-2010163234000.250m.jpg
stevengoddard,
I think that PIOMAS is likely correct and, based in part on that, yes, I think that there will be low ice extent this year – either lowest or second lowest. If I am wrong then I will be happy to revise my opinion of PIOMAS.
Amino,
You say “The reason is is that the PIOMAS graph claims that Arctic ice continues to decrease since 2008. But real data shows it is increasing.”
Both PIPS and PIOMAS are models. PIPS uses SSMI- derived ice extents (but not concentrations) to derive modelled maps of thickness and concentration, while PIOMAS in addition uses ice-thickness measurements where available.
The only extensive data which allows a full determination of the total ice volume comes from IceSat measurents made each November. Here again is the comparison of IceSat to the output of the two models, PIPS2 and PIOMAS: http://img811.imageshack.us/img811/5835/pipsvspiomas.png
The agreement is pretty good between both models and the data, though PIOMAS performs a little better. Both models and data show large ice-volume losses for the last few years, with the models agreeing there has been no recovery after 2008.
What are your reasons for believing otherwise?
R.Gates: Up until today I reckoned you had a fair point about PIPS3.0, but your assertion (unproved statement of fact) that the Navy were using PIPS3.O, but weren’t telling us they were because it’s top secret is daft. They’ve told us they’re developing it, so even by the bureaucratic idiocies of the security service, with which I have some passing acquaintance, using it and pretending they don’t makes no sense.
Then there’s your assertion that it shows considerably less ice extent/concentration/thickness than PIPS2.0. You’ve just explained to us that it’s a secret, a closely guarded pearl of intelligence in the fight against Arctic terrorism, yet you know of, or in detail, the information it’s providing. It doesn’t make sense, unless of course you are a navy insider, blogging away in at your desk in an underground naval intelligence establishment, telling the world your bosses have a new system for measuring ice in the Arctic and it’s not the real ice the navy are reporting, the real ice, is of such strategic importance to the US that they are putting out false data to fool…well who are they trying to fool? The Russkies? I doubt it they have a pretty good handle on the Arctic. The Chinese, well probably not as they’re too busy making everything and collecting the world’s entire money supply in vaults in Beijing. The EU? Well that’s the prototype for the world government many in the CAGW camp want, they’d have simply ordered a Boeing load of bureaucrats knowledgable in the intricacies of pig farming to provide a report and printed it by now. So from whom is this vital intelligence being guarded? And why?
So PIOMAS model says the ice is getting thinner and PIPS v2 model says the ice is getting thicker?
Satellite don’t give us any thickness data for the past couple of years?
So do we have any other observations?
Synoptic airborne thickness surveys reveal state of Arctic sea ice cover
Christian Haas, Stefan Hendricks, Hajo Eicken, and Andreas Herber
GEOPHYSICAL RESEARCH LETTERS, VOL. 37, L09501, doi:10.1029/2010GL042652, 2010
This paper compared airbourne measurements in spring 2007 with measurements in spring 2009. They show that the ice has got a little thicker. For example “Modal thickness increased from 2.4 to 2.8 m at the North Pole” They say most of the increases are within the limits of “natural variations”.
So this set observations suggest the ice has got thicker. Does anybody know of any other direct observations that might shed light on the situation?
“My model is better than your model” is becoming a little bit boring.
Another issue I have is that the publications around PIOMAS never actually acknowledge the existence of PIPS which proceeded it. It seems a natural thing to do to directly compare a new tool like PIOMAS with those that are already available. I haven’t read a PIOMAS paper that even acknowlkedges PIPS existence in the introductions or discussions.
Finally I found a new 2010 publication by Posey on the development of PIPS v3
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA513212&Location=U2&doc=GetTRDoc.pdf
Tom P.
Thanks for the plots of the PIPS data through the latest 2010 information.
The volume appears to be recovering from the 2007 area low and 2008 volume low.
The 2010 level are greater than 2009. likely because of the increase in muli-year ice.
The PIOMAS comparison chart is intersesting, comparing the November lows.
If that indicates the PIPS volume method and PIOMAS volume methods are similar, I wonder why the more recent data for spring 2010 is so remarkably different. The PIPS method indicates a volume increase, the PIOMAS plots suggest a dramatic drop.
And that plane survey paper indicated the ice was thicker this year that last year. That measured trend suggests the PIPS results fit with that piece of the puzzle. But that doen’t fit with that PIOMAS severe drop down for 2010. Hmmmm?
R Gates
My common sense tells me that if there is such a strategic advantage to using PIPS 3.0 over V2.0 then you wouldn’t then publish the User Manual which seems to contain an explanation of all the logic and substantial parts of the code and even debugging advice.
Common sense tells me that you wouldn’t continue to publish forecasts based on an obsolete system if the people you were trying to mislead (by using data produced by an obsolete system) already knew that the system was obsolete.
Common sense tells me there is something suspicious about the way nearly all references to PIPS 3.0 on internet searches are (with the exception of the User Manual) are many years old.
I challenge your suggestion that you have provided “ample” links to the user manual and Ms Posey’s statement. The word you should have used was “repeated”.
The existence of a user manual is irrelevant – I have written may user manuals in my life and the existence of one indicates no more than there is a plan to support a product in a wider arena than the development one. I see nothing more than a first draft unless you can show otherwise. Incidentally, when producing manual (and other documents) I have been known to use simulated/modified examples of output to suit the purposes of the document, so I would not assume that the illustration on P33 is necessarily genuine (neither do I claim that it isn’t).
As for Ms Posey’s statement, I’m sure if I was developing a tool I would be using it as much as possible until I was happy that it was fully debugged and reliable. She actually says in the piece you quoted “will have completed its validation tests by mid-2009”. Now in the real world timescales slip and validations fail, so I would not be surprised if one or both have occurred which is why they are still using PIPS2.0 as the only “validated” model.
Or is this all part of the web of deciet being woven by the US military to prevent their enemies knowing what their real predictions are for Arctic ice conditions? Seriously?
stevengoddard says:
June 12, 2010 at 10:01 pm
R. Gates
PIOMAS is showing an anomaly nearly 50% larger than this date in 2007. Everyone including Joe Bastardi is forecasting a warm summer for the Arctic. How could we not set a record minimum under those conditions? Please explain.
________________
First, I don’t follow Joe Bastardi and don’t know much about what specific variables he uses for his projections, but I doubt they are as sophisticated as PIOMAS. A warm summer alone (as many people, “warmists” and AGW skeptics alike have pointed out) was not enough in and of itself to give us the big melt of 2007, nor would it be the prime factor in 2010. Specifically, the heat coming into the Arctic Ocean from both the Atlantic and to a smaller extent, the Pacific, is a prime factor. On the Atlantic side, in 2007 we had a large amount of heat coming into the Arctic through the West Spitzbergen Current (WSC). We also then had a surge of warm water and wind coming in from the Pacific side. In short, the heat flux of the WSC is very critical to the conditioning and melting of the ice. In 2008 and 2009 the heat flux of the WSC fell from the level of 2007, and we saw the resultant very modest “recovery” in the sea ice minimum, though as one knowledgable poster has pointed out, the total March to September ice loss was greater in 2008 than in 2007 even if the summer low did not quite reach the extreme of 2007. In 2010, the WSC temps are heading back up once more, though not quite at the level of 2007 yet.
PIOMAS’s projection of 4.7 million sq. km. and my own projection of 4.5 million sq. km. isn’t just based on the volume anomaly, but is also based on wind and currents and many other factors. PIOMAS lowered their own projection in their latest update to the 4.7 million mark from a previous 5.0 million, though I’ve been at 4.5 million since March. I’m not sure all the factors that PIOMAS is looking at either, and the heat flux of the WSC may or may not be one of them, but it is one of my biggies, as well as water temps and currents in the Bering Sea, total solar irradiance, GCR’s (as measured at the Moscow neutron monitor), air temps in the Arctic, the NOA and related AO index, cloud cover (especially number of days of stratus clouds), LW back-radiation, and of course air temps. So far I see nothing to change my projection of 4.5 million sq. km using all the factors mentioned above. So in short, the volume anomaly in and of itself is not the only factor to be considered.
Moderator
Thanks for the spelling correction, and for the deletion requested to an earlier post. My thanks for your collective efforts over the months and years – it’s much appreciated.