Sea Ice News – Volume 3 Number 11, part 2 – other sources show no record low Arctic ice extent

Earlier today in part1, I posted about the new record low claimed by NSIDC: Sea Ice News – Volume 3 Number 11, part 1 – new Arctic satellite extent record. The number given is 4.1 million square kilometers:

That of course is being trumpeted far and wide, new life has been given to Mark Serreeze’s “Arctic death spiral” in the media. But, here’s a curiosity, another NSIDC product, the new and improved “multi-sensor” MASIE product, shows no record low at ~ 4.7 million square kilometers:

Note the label at the bottom of the image in red. NSIDC doesn’t often mention this product in their press releases. They most certainly didn’t mention it today.

Another product, NOAA’s National Ice Center Interactive Multisensor Snow and Ice Mapping System (IMS) plot, also shows no reason for claiming a record at all:

Their number is (for 8/22) ~ 5.1 million square kilometers. (NOTE: NSIDC’s Dr. Walt Meir points out in comments that IMS and MASIE use the same base data, but that this one product from IMS only updates weekly, unlike all other sea ice plots which are daily. They should be in sync on the next update cycle, but right now MASIE and IMS should both be at 4.7 million sqkm. -A)

Another curiosity is here. On the NATICE interactive maps on demand page (click on Arctic Daily in the pulldown menu):

The numbers they give for 80% and marginal ice add up to an extent of 6,149, 305 square kilometers.

So who to believe? It depends on the method, and who thinks their method is most representative of reality. Measuring sea ice via satellite, especially when you use a single passive sensor system that has been show in the past to have degradation problems and outright failure (which I was told weren’t worth mentioning until they discovered I was right and pulled the plug)  might be a case of putting all your eggs in one basket. I suspect that at some point, we’ll see a new basket that maybe isn’t so worn, but for now, the old basket provides a comfort for those who relish new records, even though those records may be virtual.

Note that we don’t see media pronouncements from NOAA’s NATICE center like “death spiral” and “the Arctic is screaming” like we get from its activist director, Mark Serreze. So I’d tend to take NSIDC’s number with a grain of salt, particularly since they have not actively embraced the new IMS system when it comes to reporting totals. Clearly NSDIC knows the value of the media attention when they announce new lows, and director Serreze clearly knows how to make hay from it.

But this begs the question, why not move to the new system like NOAA’s National Ice Center has done? Well, it is a lot like our July temperature records. We have a shiny new state of the art Climate Reference Network system that gives a national average that is lower for July than the old USHCN network and all of its problems, yet NCDC doesn’t tell you about the July numbers that come from it. Those tasks were left to Dr. Roy Spencer and myself.

In fairness though, I asked Dr. Walt Meier of NSIDC what he thought about MASIE, and this is what he wrote to me today:

It can provide better detail, particularly in some regions, e.g., the Northwest Passage.

However, it’s not as useful for looking at trends or year-to-year

variations because it is produced from imagery of varying quantity and quality. So the analyses done in 2007 have different imagery sources than this year. And imagery varies even day to day. If skies are clear, MODIS can be used; if it’s cloudy then MODIS is not useful. Another thing is that the imagery is then manually analyzed by ice analysts, so

there is some subjectivity in the analysis – it may depend on the amount of time an analyst has in a given day.

Our data is from passive microwave imagery. It is not affected by clouds, it obtains complete data every data (except when there may be a sensor issue), it has only consistent, automated processes. So we have much more confidence in comparing different days, years, etc. in our passive microwave data than is possible using MASIE.

Finally, MASIE’s mandate is to try to produce the best estimate they can of where there is any sea ice. So they may include even very low concentrations of ice <15%. In looking at visible imagery from MODIS, in the few cloud-free regions, there does appear to be some small concentration of ice where MASIE is mapping ice and our satellite data is not detecting ice. This is ice that is very sparse, likely quite thin. So it will probably melt out completely in the next week or two.

MASIE has tended to lag behind our data and then it catches up as the sparse ice that they map disappears. This year the difference between the two is a bit larger than we’ve seen in other years, because there is a larger area of sparse ice.

You can thank the big Arctic storm of August 4th-8th for that dispersal.

The Great Arctic Cyclone of 2012″ effect on Arctic sea ice is seen in  this before and after image:

Figure 4. These maps of sea ice concentration from the Special Sensor Microwave Imager/Sounder (SSMIS) passive microwave sensor highlight the very rapid loss of ice in the western Arctic (northwest of Alaska) during the strong Arctic storm. Magenta and purple colors indicate ice concentration near 100%; yellow, green, and pale blue indicate 60% to 20% ice concentration.

Credit: National Snow and Ice Data Center courtesy IUP Bremen

High-resolution image

Trends -vs- records, just like July temperatures. One system might be better at trends, another might be better at absolutes used to determine records. In this case we have three other respected methods that show absolute values higher than that of NSIDC’s older method which they have a high confidence in. I suppose these systems are like children. In a competition, you always root for your children over the children of the other parents, so it is no surprise that NSIDC would root for their own well known media star “child” over that of NATICE’s IMS and NSIDC’s own lesser known child, MASIE.

Oh, and then there’s Antarctica, that other neglected ice child nobody talks about, with its above normal ice amounts right now:

No matter what though, its all just quibbling over just a little more than 30 years of satellite data, and it is important to remember that. It is also important to remember that MASIE wasn’t around during the last record low in 2007, and IMS was just barely out of beta test from 2006. As measurement systems improve, we should include them in the discussion.

UPDATE: Andrew Revkin reports on the issue in his Dot Earth article here

He’s a bit skeptical of the sound byte hype coming from NSIDC writing:

That’s one reason that, even with today’s announcement that the sea ice reached a new low extent for the satellite era, I wouldn’t bet that “the Arctic is all but certain to be virtually ice free within two decades,” as some have proposed. I’d say fifty/fifty odds, at best.

But is this a situation that is appropriately described as a “death spiral”? Not by my standards.

Revkin also takes Al Gore to task on Twitter:

help him out, retweet this

UPDATE2:  Commenter Ron C. provides this useful information in comments that helps explain some of the differences and issues:

The main point is that NIC works with images, while the others are microwave products.

“Polar orbiting satellites are the only source of a complete look at the polar areas of the earth, since their orbits cross near the poles approximately every two hours with 12 to 13 orbits a day of useful visible data. This visible imagery can then be analyzed to detect the snow and ice fields and the difference in reflectivity of the snow and ice. By analyzing these areas each day, areas of cloud cover over a particular area of snow and ice can be kept to a minimum to allow a cloud free look at these regions. This chart can then be useful as a measure of the extent of snow and ice for any day during the year and it can also be compared to previous years for climatic studies.”

http://www.natice.noaa.gov/ims/snow_ice.html

“NIC charts are produced through the analyses of available in situ, remote sensing, and model data sources. They are generated primarily for mission planning and safety of navigation. NIC charts generally show more ice than do passive microwave derived sea ice concentrations, particularly in the summer when passive microwave algorithms tend to underestimate ice concentration. The record of sea ice concentration from the NIC series is believed to be more accurate than that from passive microwave sensors, especially from the mid-1990s on (see references at the end of this documentation), but it lacks the consistency of some passive microwave time series. ”

http://nsidc.org/data/g02172.html

Some have analyzed the underestimation by microwave products.

“We compare the ice chart data to ice concentrations from the NASA Team algorithm which, along with the Bootstrap algorithm [Comiso, 1995], has proved to be perhaps the most popular used for generating ice concentrations [Cavalieri et al.,1997]. We find a baseline difference in integrated ice concentration coverage north of 45N of 3.85% ± 0.73% during November to May (ice chart concentrations are larger). In summer, the difference between the two sources of data rises to a maximum of 23% peaking in early August, equivalent to ice coverage the size of Greenland.”

From Late twentieth century Northern Hemisphere sea-ice record from U.S. National Ice Center ice charts, Partington, Flynn, Lamb, Bertoia, and Dedrick

http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1058&context=usdeptcommercepub

The differences are even greater for Canadian regions.

“More than 1380 regional Canadian weekly sea-ice charts for four Canadian regions and 839 hemispheric U.S. weekly sea-ice charts from 1979 to 1996 are compared with passive microwave sea-ice concentration estimates using the National Aeronautics and Space Administration (NASA) Team algorithm. Compared with the Canadian regional ice charts, the NASA Team algorithm underestimates the total ice-covered area by 20.4% to 33.5% during ice melt in the summer and by 7.6% to 43.5% during ice growth in the late fall.”

From: The Use of Operational Ice Charts for Evaluating Passive Microwave Ice Concentration Data, Agnew and Howell

http://www.tandfonline.com/doi/pdf/10.3137/ao.410405

 

 

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This is my shocked face.

Anthony, some one pulled me up for the mis-use of the phrase ‘begs the question’ a few weeks ago.
From wikipedia
Begging the question (Latin petitio principii, “assuming the initial point”) is a type of logical fallacy in which a proposition relies on an implicit premise within itself to establish the truth of that same proposition. In other words, it is a statement that refers to its own assertion to prove the assertion. Such arguments are essentially of the form “a is true because a is true” though rarely is such an argument stated as such. Often the premise ‘a’ is only one of many premises that go into proving that ‘a’ is true as a conclusion.

MASIE and IMS are the same thing – MASIE takes its sea ice data from IMS. So you can’t count it twice. It’s also misleading of you to mention MASIE / IMS without saying that it currently has 2012 as lowest on record for the time of year (lower than 2007) – it just hasn’t set a new record yet.
Finally, the melt season is not over yet. Will you put up a new post with equal prominence if/when MASIE also shows this year as a new record?
REPLY: MASIE/IMS – They are two different products, done by two different agencies, showing two different numbers. If they were identical numbers you’d have a point. As for showing it, actually I’ll do better than that, I’ll include MASIE in the WUWT sea Ice Page so we all can watch it. – Anthony

How can NSIDC have an activist director, like Mark Serreze? I would frankly expect his ‘thumb’ to be on the scale during any ‘weighing’ …
(Do we normally charter a ‘fox’ to watch the hen house?)
Has NSIDC ever been audited? Are their practices, their procedures compliant or according to ISO standards and are they available for inspection?
.

F. Ross

Don’t worry these figures will soon be adjusted to compliance with the “record low.”
/sarc

Goldie

Seems to me we were not questioning the method when it didn’t show “record lows”. I’d be much more interested in two things; 1) Why is it low this year and 2) do we really have sufficient years to be stating record anything?
REPLY: Masie didn’t exist until 2010, and IMS is also relatively new, starting in 2006. Neither has gotten much press, so few know about them. There really wasn’t much else besides NSIDC, JAXA, and Cryosphere Today in 2007 when the last satellite record low was set. – Anthony

Dave

Why not ask an Eskimo?

Steven Hill

It’s the lowest ice amount in 1 billion years……we are all doomed. 😉

a jones

I have said it many times on this blog before and I will repeat myself.
Please wake me up when something interesting happens at the North pole.
Perhaps finding the pot of gold at the end of the rainbow and even Santa’s grotto.
Otherwise the ice will do as the ice will do.
And there is no doing anything about it.
Kindest Regards

mortis88

ummm, Philip, “begging the question” means that there is an obvious, unanswered question. Wiki is a horrible reference tool

Louis Hooffstetter

If true, this surely amounts to fraud:
“A false representation of fact – whether by words or by conduct, by false or misleading allegations, or by concealment of what should have been disclosed – that deceives and is intended to deceive another…”

Steven Hill

We are all like frogs placed in a pan of water heating on the stove….slowly cooking to death with man made CO2 causing the sun to bake us to death slowly. Where is Al Gore when you need him. We need another peace prize awarding movie! Where are you Al? Help us! LOL

I’ll make a few points for clarification on the post above. First, MASIE and IMS are the same product. MASIE is simply a repackaging of the IMS data in easier to use formats. IMS is produced by the National Ice Center (NIC), using similar sources and methods as they use for their daily interactive maps. So all three of the examples provided are closely related and not independent measurements.
The passive microwave estimates all show a record low for the Arctic. These aren’t completely independent either – they all measure microwave emission, but there are difference sensors (SSMIS, WindSat, and for the first time AMSR2: http://www.eorc.jaxa.jp/en/imgdata/topics/2012/tp120825.html, which is pretty exciting), and there are different processing methods as well. There can always be potential errors in data, especially in near-real-time, so having multiple sensors showing consistency provides confidence that one sensor doesn’t have an error, which has happened from time to time. When it does, we go back and reprocess and correct the errors.
I worked at the National Ice Center for a couple years and have collaborated with them many times since, so I’m familiar with their methods and their focus. Their mandate is to map as much as ice as possible as accurately as possible each day and week in support of ships (particularly DoD ships) operating in and near ice-covered waters. They work hard on getting today’s data analyzed and then tomorrow they start over. They are not concerned with the past. If they can detect more ice today than yesterday, then they map it. If they lose a sensor, they do the best they can with what they have left. If they make an error, they don’t go back and correct it -it’s on to the next day. NIC doesn’t discuss climate or climate change because that is not their purpose and from my experience working there, they just don’t have the time – they’re focused on the here and now.
The charts are produced manually, so there is subjectivity in the analysis that we don’t have in our fully automated processing. This means that there can even be inconsistencies in adjacent regions if they were analyzed by different people.
They have created an archive of their weekly ice charts, which is archived at NSIDC: http://nsidc.org/data/g02172.html. There was some attempt to homogenize the charts (at least remove regional discrepancies) during the production, but they do not produce a consistent timeseries. MASIE, though it only goes back to 2006, has similar issues of consistency.
The folks at NIC do a great job at what they’re focused – navigational support. MASIE is an excellent data set and we at NSIDC find it very useful looking at specific details about the ice (e.g., is the Northwest Passage open or not), but the NIC products are not applicable to studying climate-scale changes.
Walt Meier
NSIDC
REPLY: Walt, respectfully, MASIE says 4.7, IMS says 5.1. If MASIE and IMS are the same product, how can they show different numbers? In your “repackaging” don’t you manage the IMS data to your methods in some way, resulting in a different end number? The differences in the 4.7/5.1 would seem to suggest you drop out some IMS data.
IF IMS products are only useful for navigation, why give a total extent value?
As for “usefulness in studying climate” no data set just a few years old can be useful for trends. They can however be useful for absolutes. For example you cite the new AMSRE2 data in that context. At just over 30 years old now, SSMI data used by NSIDC/CT is just barely above the threshold for a climate capable data set.
I suppose NSIDC would be a lot more believable to me if Serreeze wasn’t so focused on making pronouncements.
I’ll point out to readers that this year, WUWT, Meier, and Stroeve, all came to the same conclusion for September minimum in the ARCUS forecast – 4.5 million sqkm, something that suggests we aren’t as “breathtakingly ignorant” as director Serreze claims. – Anthony

Looking at Anthony’s comments, perhaps one further clarification that may arise from my previous comment. The MASIE product came out in 2010; historical data was run going back to 2006. And again to confirm, MASIE and IMS are the same product. There may be some slight differences in numbers because of how the data is gridded and projected, but they’d be minor.
Walt Meier
NSIDC
REPLY: 4.7 -vs- 5.1 are minor differences in the “same” product? If even a 0.1 threshold was breached for a new record, NSIDC would claim a new record, as has been done today – Anthony

Hi, Anthony,
i agree with you that the data gathering methodology is certainly suspect, but it is interesting to me that there are several sources catching this extremely low amount. I still would be surprised to see a “real” record low show even on the alternate sources.
But here’s the kicker… does that mean we’re a-roasting? I don’t think so. Global average temps are sliding now +.28C, which is not much at all, and the cumulative anomaly from January to July was just +.001C (Dr Ryan Maue, Weatherbell.com) which is basically nothing. Further, the history you occasionally post yourself indicates periods that were quite ice-free in the Arctic within the last century, and we had cold winters then and hot summers then, as now.
i think that there are certainly more questions than answers in reality. I think there is an assumption that Sea Ice in the Arctic has a direct relation to the severity of northern hemisphere winters, when most likely the opposite is true, since the rapid and deep cooling happens over land areas, and not over water. I am not sure how much heat loss takes place above the Arctic circle – I mean, sure it’s dark there during the winter – at least having no direct sunlight, but how does even solid sea ice compare in heat loss to land areas? I don’t know that – no one talks about that in “pop climate” circles…
I guess we’ll only really know when it’s all done. Keep up the good fight!

Thanks, Anthony. Good to know about the National Ice Center – IMS Products.

Steven Hill

NIC products are not applicable to studying climate-scale changes? We use Al and Hansen for that part. 😉

Steven Hill

We might want to look at something that is going to happen….flooding. http://www.hpc.ncep.noaa.gov/tropical/qpf/tcqpf.php

pat

c’mon folks, we need sensational headlines to go with the constant push for CO2 revenue-raising:
27 Aug: Washington Post Ezra Klein’s Wonkblog: Brad Plumer: Could a carbon tax help the U.S. avert the fiscal cliff?
With the United States facing the expiration of a slew of tax cuts in 2013—the dread “fiscal cliff”—there has been plenty of interest in offbeat tax-reform proposals. And one idea that a few economists keep knocking around is a fee on carbon emissions. After all, if we need to raise revenue, why not just tax global-warming pollution?
A new paper from the MIT Global Change Institute lays out how a carbon tax might work in practice…
According to MIT calculations, a modest carbon tax, on its own, wouldn’t get the United States close to that longer-term mark. It might make sense as a more economically efficient way of raising revenue. But the tax would either have to be hiked dramatically or combined with other clean-energy measures in order to make a significant dent in tackling global warming.
http://www.washingtonpost.com/blogs/ezra-klein/wp/2012/08/27/how-a-carbon-tax-could-help-the-u-s-avert-the-fiscal-cliff/

Nicholas in the Jerry Moonbeam Kalifnutso state

WUWT is my first morning read.
The last week left me disappointed since Steve Goddard has posted
material during the last week indicating the government supplied charts on WUWT
may not be an accurate indication of the Artic ice conditions!
I wondered each day when material would appear and 8/27 is finally the day.

Paper finds Arctic sea ice extent 8,000 years ago was less than half of the ‘record’ low 2007 level
http://hockeyschtick.blogspot.com/2012/08/paper-finds-arctic-sea-ice-extent-8000.html

Mjk

Anthony,
Why question the method only after a new record low has been reached? It harms your credability as an objective observer.
Mjk
REPLY: Because these are new methods that aren’t getting any attention. MASIE wasn’t around in 2007, and IMS was just barely out of beta test. Measurement of sea ice from space is not an exact science, as these different methods show. As an objective observer I reported on NSIDC’s numbers first, then I point out that other newer data sets show different values. A non-objective observer would have only reported one side of the story, I reported both. How many news article report both sides of the story on sea ice today?
Therefore, your claim isn’t valid except in the minds of the haters. – Anthony

Michael U

So, not being a trusting person … I went to the sources.
Masie is reporting 4.7 million square kilometres of ice, and NSIDC SII 4.1 million square kilometres. Nasie has 4km resolution, SII 25km resolution.
Back in 1963, surveillance satellites used in the Cold War could find an object 2 feet wide on the ground. Now the best we can do to monitor ice is either 25km or 4km resolution.
Anyway, let’s say that the 600,000 square kilometres of ice that the SII can’t see is less than its reported 15% ice extent. 7.5% for assumption. And, let’s say it is half the thickness of its lowest reported thickness of 0.5 metres. So, 0.25 metres thick (25cm or 10 inches).
So, 600,000 km2 X 7.5% is 45,000 square kilometres of ice 25cm thick. A square kilometre is 1 million square metres. So, 45 billion square metres of 25cm ice is 11.250 billion cubic metres of ice, or about a trillion cubic feet. Seems like a lot of missing ice to me! Compare: The BP oil spill in the Gulf of Mexico was 0.00078 billion cubic metres of oil (780,000 m3 of oil vs 11,250,000,000 m3 of “missing” ice). That’s only 14,423 BP oil spills of ice missing from the SII data set! The proven oil reserves in Saudi Arabia are about 27 billion bbls, which is about 4 billion m3 of oil or about 1/4 of the missing ice.
I go ice fishing on a lake in Canada every winter. It is 15 square kilometres and the ice gets close to a metre thick. So, 15 million m3 of ice in that lake is a rounding error in the missing ice world of the NSIDC. I’ll have to tell my buddies next winter to forget taking the ice auger, that lake is ice free according to the US government! We can just go and drop our lures and catch some fish!
Anyway, the MASIE site breaks down the ice by region. For example, the Beaufort Sea shows 300,700 square kilometres of ice, which is a huge drop from a couple of weeks ago. The steep drop indicates something other than temperature melting the ice, perhaps this “famous” storm. The Chukchi sea has its second highest sea ice extent in the most recent 5 years (which is what is graphed on the site). In contrast, Hudson’s Bay is showing its highest extent in 5 years at 67,400 km2 of ice. And the Central Arctic, which is where the thick ice is, is showing over 3 million km2 of ice extent. The Central Arctic is almost exclusively north of 80N. At 82.3N, the northernmost reported Canadian weather station shows a daytime high of -1C today, so it looks like the melting season has ended there. It was a whopping 3C over the weekend and below zero last week as well. The ice there is 4.5m thick, so it is unlikely to completely melt any time soon. November mean daily temperatures average -20C, and by the end of the first week of September Alert Nunavut won’t see anything exceeding 0C until the end of May.
But, isn’t this all to do about nothing? Natural variations in sea ice extent account for all of this. We only have 30 (or 43) years of satellite measurement of sea ice extent, during which time the instrumental record of temperatures shows a cyclical high, although for North America the 30’s were significantly warmer and parts of the 50’s were close. If ice extent gets under 3 million square kilometres, then it’s an event. Until then, no one should be excited.

George

Snap Quiz:
What was the Earth like before there was an Arctic?
Extra points: When did the Arctic start?

Owen in Ga

Anthony,
All this moderation! I thought you were on a much needed vacation. Can’t some of the trusted moderators handle some of the snide/inaccurate remarks while you get some much needed rest?
(That’s all right, I checked your page every day on my vacation too!)
REPLY: Ever Since Bob Phelan died, it has been extra work – We all miss him – Anthony

owl905

It’s not often that you see schlep this bad presented as a counter-argument. Bad angle, Tony T. Your forecast of the end of the ‘Modern Global Warming Period’ is like something else … on fire.
REPLY: I think maybe this comment was intended for another thread. There’s no Tony T. nor ‘Modern Global Warming Period’ on this thread – Anthony

Nicholas in the Jerry Moonbeam Kalifnutso state

“What was the Earth like before there was an Arctic?”
How do sea shell fossils exist at 2500 feet in the Oregon coast range?

Theo Goodwin

mortis88 says:
August 27, 2012 at 4:16 pm
“ummm, Philip, “begging the question” means that there is an obvious, unanswered question. Wiki is a horrible reference tool”
Sorry, it means arguing in a circle. Check out the bible of logic texts, Irving Copi’s Introduction to Logic. I began teaching from it in the Sixties. Also, the fallacy’s pedigree is pretty long. It goes back to Socrates in 400 BC.
The growing misuse of “begs the question” comes from some muttonhead TV talking head who thought it must mean that the discussion so far has reached a point where another question, an additional question, begs to be answered. That use is growing in popularity. But don’t try it around anyone who is familiar with logic.

Dave

I find it a bit odd of reports Arctic shipping took advantage of the worst Arctic storm in living memory.

Anthony,
Sorry, I probably should’ve pointed out that the IMS number of 5.1 is if you look at the graph for August 22. That IMS plot only gets updated once a week I believe. MASIE is updated daily and the extent has declined since the 22nd.
I also didn’t point out that MASIE is a single day number while IMS is a three-day average, so that will be somewhat different.
But: they are exactly the same product. Same input data, same analysts working on it, same final results.
Walt Meier
NSIDC
ps – someone else may have caught this already, but I have to head out and don’t have time to read through recent comments to check, so apologize if I repeated something that’s already been addressed in the comments.
REPLY:Yep, my mistake on the IMS graph. I didn’t realize it was weekly rather than daily like all other similar ice products. But that sort of goes against your claim of “repeat daily” at NATICE. OK then you should probably take steps at NSIDC to notice readers of the differences and why. What about the daily IMS map, that’s way higher? – Anthony

Tez

There was less arctic ice for a period of over 400 years when the vikings were farming Greenland.
If this current situation continues for 400 years then I might start to get concerned.

Pony

IMS stops at 8/22 while MASIE is currently at 8/26, a difference of 4 days.
It also appears that the IMS graph uses a 2-day smooth versus tha MASIE daily values.
I get 5.14 for IMS on 8/22 (using 8/21 and 8/22 MASIE dailies).

owl905

No, it was meant for you here. hth.
REPLY: Hope this helps…uh no, there’s still no Tony T. nor forecast you refer to. – Anthony

pjie2

Anthony, look at the IMS graph you posted. Note the date on it (Aug 22nd), and that it clearly states it’s a 3-day mean. Then check the MASIE data here:
ftp://sidads.colorado.edu/DATASETS/NOAA/G02186/masie_extent_sqkm.csv
I’m not sure if it’s a trailing mean (average of days 233/234/235) or centred (average of 234/235/236). It doesn’t actually matter since both happen to give the same result for the 22nd, and it’s 5.1 as stated on the IMS graph.
MASIE=IMS

Darn. It doesn’t look like I’ll be able to water ski at the North Pole this year. Maybe next year. Anyone have a jet ski they wouldn’t mind bouncing into baby icebergs that’s capable of hauling a waterskier?

Stu N

“But, here’s a curiosity, another NSIDC product, the new and improved “multi-sensor” MASIE product, shows no record low at ~ 4.7 million square kilometers:”
– I can only download 4 weeks worth of data from the link in your post. Is 4.7 million sq km a record as measured by MASIE? I don’t know, I need the whole dataset! You certainly can’t compare it to the 4.1 million sq km calculated using a different method.
Additionally, IMS is tracking at a record low for the date, isn’t it?

Richdo

Dave says:
August 27, 2012 at 4:09 pm
Why not ask an Eskimo?
————————————
That’s too easy and doesn’t require the expenditure of 10^7’s$ to support the apparatchik.

mortis88 says:
August 27, 2012 at 4:16 pm
ummm, Philip, “begging the question” means that there is an obvious, unanswered question. Wiki is a horrible reference tool

I don’t want to turn this into an English usage thread. But I think you will find the wikipedia reference is correct.
FWIIW, I decided to no longer use the phrase because it is so widely ‘misused’.

owl905

owl905 says:
August 27, 2012 at 5:15 pm
No, it was meant for you here. hth.
REPLY: Hope this helps…uh no, there’s still no Tony T. nor forecast you refer to. – Anthony
That’s about as swift as your IMS=MASIE responses. Go check your notes on how the funk in the Solar Cycles will put an end to the warming Tony. Or parrot another weak response, your choice.

REPLY:
Ah, a smartass who speaks in tongues, noted for future bit bucketing. – Anthony

F. Ross

owl905 says:
“That’s about as swift as your IMS=MASIE responses. Go check your notes on how the funk in the Solar Cycles will put an end to the warming Tony. Or parrot another weak response, your choice.”
Kind of unseemly to insult your host, don’t you think? But then …your choice.

Ron Clutz

Here’s some more background on this issue(also posted at the Blackboard and Real Science.)
The main point is that NIC works with images, while the others are microwave products.
“Polar orbiting satellites are the only source of a complete look at the polar areas of the earth, since their orbits cross near the poles approximately every two hours with 12 to 13 orbits a day of useful visible data. This visible imagery can then be analyzed to detect the snow and ice fields and the difference in reflectivity of the snow and ice. By analyzing these areas each day, areas of cloud cover over a particular area of snow and ice can be kept to a minimum to allow a cloud free look at these regions. This chart can then be useful as a measure of the extent of snow and ice for any day during the year and it can also be compared to previous years for climatic studies.”
http://www.natice.noaa.gov/ims/snow_ice.html
“NIC charts are produced through the analyses of available in situ, remote sensing, and model data sources. They are generated primarily for mission planning and safety of navigation. NIC charts generally show more ice than do passive microwave derived sea ice concentrations, particularly in the summer when passive microwave algorithms tend to underestimate ice concentration. The record of sea ice concentration from the NIC series is believed to be more accurate than that from passive microwave sensors, especially from the mid-1990s on (see references at the end of this documentation), but it lacks the consistency of some passive microwave time series. ”
http://nsidc.org/data/g02172.html

mortis88 says:
August 27, 2012 at 4:16 pm
ummm, Philip, “begging the question” means that there is an obvious, unanswered question. Wiki is a horrible reference tool

The phrase that used to be used in that situation was, “That raises the question.” That’s the phrase we should revert to. It does the job and it doesn’t step on the toes of the other phrase, which has a specialized meaning.

Ron Clutz

Some have analyzed the underestimation by microwave products.
“We compare the ice chart data to ice concentrations from the NASA Team algorithm which, along with the Bootstrap algorithm [Comiso, 1995], has proved to be perhaps the most popular used for generating ice concentrations [Cavalieri et al.,1997]. We find a baseline difference in integrated ice concentration coverage north of 45N of 3.85% ± 0.73% during November to May (ice chart concentrations are larger). In summer, the difference between the two sources of data rises to a maximum of 23% peaking in early August, equivalent to ice coverage the size of Greenland.”
From Late twentieth century Northern Hemisphere sea-ice record from U.S. National Ice Center ice charts, Partington, Flynn, Lamb, Bertoia, and Dedrick
http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1058&context=usdeptcommercepub
The differences are even greater for Canadian regions.
“More than 1380 regional Canadian weekly sea-ice charts for four Canadian regions and 839 hemispheric U.S. weekly sea-ice charts from 1979 to 1996 are compared with passive microwave sea-ice concentration estimates using the National Aeronautics and Space Administration (NASA) Team algorithm. Compared with the Canadian regional ice charts, the NASA Team algorithm underestimates the total ice-covered area by 20.4% to 33.5% during ice melt in the summer and by 7.6% to 43.5% during ice growth in the late fall.”
From: The Use of Operational Ice Charts for Evaluating Passive Microwave Ice Concentration Data, Agnew and Howell
http://www.tandfonline.com/doi/pdf/10.3137/ao.410405

Steve from Rockwood

It does look pretty ugly – meaningless – but I think a new record low will be set in 2012.

I think the neglect of people to talk about the Medieval Warm Period when talking about Arctic ice is sinful.

Well it is interesting that the claims are of a record low, while the Seattle Times has an article about drilling in the Arctic being held up by ice in the Chuki (sp) sea.

Elizabeth

Here in the center of South America sub tropics 4C at the moment about -20C off scale it sure the hell is warming up!
http://wxmaps.org/pix/sa.00hr.html

Arno Arrak

I am not surprised that it happened. The area of Arctic sea ice has been shrinking at the rate of 11 percent per decade for the last 30 years. The year 2007 was exceptional because poleward winds pushed a lot of warm water through the Bering Strait which then proceeded to melt a huge batch of ice directly north of it. At the same time the Russian side of the ocean remained undisturbed. Claims that global warming caused it were shown to be false when more normal ice conditions returned next year. But the trend I mentioned is still active and I knew that eventually it would reduce the area of Arctic ice to 2007 levels and even lower. That is because the Arctic is warming and has been since the beginning of the twentieth century. Prior to that there was nothing but two thousand years of slow cooling. The warming started suddenly at the turn of the century, paused in mid-century, then resumed, and is still going strong. There was no parallel increase of atmospheric carbon dioxide when the warming began and this rules out the greenhouse effect as a cause. That is because infrared absorbance of carbon dioxide is a physical property of the gas and cannot be changed. If you want it to absorb more to create warming you must increase the amount of gas that is doing the absorbing and this did not happen. Absence of the greenhouse effect also explains why climate models based on it have totally failed to predict the Arctic warming correctly. It is two to four times faster than those models predict. Apparently a rearrangement of the North Atlantic current system at the turn of the century caused the currents to start carrying warm Gulf Stream water into the Arctic Ocean. Direct measurements of current temperature reaching the Arctic in 2010 showed that it exceeded anything measured for the last two thousand years of Arctic history. See E&E 22(8):1069-1083 (2011).

Walt Meier

On the discussion of the comparisons between PM sensors and NIC products, note that they’re talking about area (I.e., weighted by concentration). There is a well-known bias in PM area estimates due to surface melt and weather. However, this is much less of an effect for extent, which is a simple ice or no-ice threshold. There can sometimes be larger discrepancies in rare cases like this year with the sparse ice regions, but PM and NIC extents generally are pretty close, especially when accounting for the fact that NIC maps all ice.
Walt Meier
NSIDC

Tony, don’t you ever get tired of all of this?
Stuff happens: it’s not happening! How can we know what happened 20 [years, decades, centuries, whatevs] ago to compare with today?
It’s happening: but it’s not so bad! In fact, people 20 [years, decades, centuries, whatevs] ago enjoyed the heat!
We could do a little something about it: oh noes! We will all suffer an economic fate at least one 20th as bad as the ’08 economic meltdown which occurred because we didn’t do anything about it! And millions of people will die because we feared what the alarmists told us!
C’mon; rinse-lather-repeat. Don’t you ever get tired of this nonsense?