# What Is Normal Arctic Ice Extent?

Guest post by Steven Goddard

I have been noticing in recent weeks that NSIDC extent is much closer to their 1979-2000 mean than NANSEN is to their 1979-2007 mean.  This is counter-intuitive, because the NANSEN mean should be relatively lower than NSIDC – as NANSEN’s mean includes the low extent years of the 2001-2007 period.  Those low years should have the effect of lowering the mean, and as a result I would expect the NANSEN current extent to be equal to or above the 1979-2007 mean.

(For exclusive subsets A and, B where subset A has a mean value of 14 and subset B has a mean value less than 14, then the mean of the full set AB must also be less than 14.)
I overlaid the NANSEN graph on top of the NSIDC graph below, and it is easy to see how large the discrepancy is.  In fact, the NSIDC mean sits at about one standard deviation below the NANSEN mean – which makes little sense given their base time periods.  It should be the opposite way.

(Note – the NANSEN and NSIDC measuring systems are not identical, and I had to make a shift along the Y-axis to line them up.  However, the X and Y scales are identical for both graphs in the overlay image.)

NANSEN and NSIDC combined
As mentioned above, one might expect that the current NANSEN extent would actually be above the 1979-2007 mean.  But something odd happened with the NANSEN data on December 13, 2008.  Overnight it lost about 500,000 km2 of ice, as Anthony captured in the blink comparator below.
Is it possible that there is still an error in the NANSEN data?  The discrepancy in the offset from the mean vs. NSIDC is rather large – nearly large enough to place California inside.  What are your thoughts?
I asked Dr. Walt Meier from NSIDC his opinion, and he replied (as always) courteously and promptly.  His answers are below:

Nansen uses a different algorithm to calculate the sea ice extent. The algorithms differ in the way combine the raw data together to estimate extent. As long as one uses the same algorithm, the stories are all the same, but the details can differ, more so at certain times of year. When there is a diffuse, broken up ice edge and melt is starting is one such time.

I suspect the Bering Sea is probably the region resulting in most of the differences. While our algorithm shows the region has mostly “ice-covered” the ice cover there is very fragmented, broken-up, and thin.

….

The other thing that’s important to mention is that I was referring simply to discrepancy between how close the current lines are to climatology. However, there is also generally an “offset” between algorithm outputs – a bias or mean difference between the algorithms that is fairly consistent throughout the record. That is why NSIDC’s climatology is different than the Nansen climatology.

The important thing to remember is that there is a good consistent record from the passive microwave data as long as you consistently use the same algorithm and the same processing. But you can’t mix and match products.

## 126 thoughts on “What Is Normal Arctic Ice Extent?”

1. TERRY46 says:

As always if you don’t like the outcome just move the goal post.

2. Aron says:

Blatant lies:

http://www.guardian.co.uk/environment/2009/apr/28/climate-change-poles

“In the past four years, air temperatures have increased, sea ice has declined sharply, surface waters in the Arctic ocean have warmed and permafrost is in some areas rapidly thawing.”

Note the use of alarmist language “sharply” and “rapidly”

3. Mike Bryant says:

I appreciate the answer from Meier, but I am not sure it goes to the heart of the discrepancy. What am I missing?
Mike

Also, according to CT the Global Sea Ice Anomaly is now 765,000 sq. km. which is a large enough area to contain, Virginia, West Virginia, Louisiana, Mississippi, Ohio, Maine and Pennsylvania. Oh yeah Rhode Island and D. C. will fit in there too…

4. Aron says:

I posted this as a public note on Facebook:

“Read this article by the Guardian’s John Vidal (a man who enjoys lying so much that he probably has bought himself a golden throne to go with his ego)

http://www.guardian.co.uk/environment/2009/apr/28/climate-change-poles

Sounds frightening doesn’t it? Let’s take a look at just one sentence of it:

“In the past four years, air temperatures have increased, sea ice has declined sharply, surface waters in the Arctic ocean have warmed and permafrost is in some areas rapidly thawing.”

Notice the use of alarming language designed to create public hysteria. Now let’s take a look at how Arctic Ice is really doing according to the National Snow and Ice Data Center (NSIDC).

As you can see, arctic ice is in a very healthy state. It’s been growing yearly for the past few years and is almost back up to its long term average. So where did John Vidal get the idea that ” sea ice has declined sharply, surface waters in the Arctic ocean have warmed and permafrost is in some areas rapidly thawing”???

The Guardian lies every single day. It’s that simple. Their agenda is to force you to believe the world is going to end unless you change your ways and conform to their mind controlling, soul destroying socialism.

Stick your middle finger up to them. Go enjoy your lives and live the way YOU want to live.”

5. Paul James says:

“nearly large enough to place California inside”

YIKES !!!

Ring the alrm bells !!!!

Has any one told Mr Waxman that CA was moved North and then apparently melted ? Or did it evaporate ? I always have trouble keeping those two in order.

6. Paul says:

Just out of curiosity, why doesn’t NSIDC use the 1979-2007 average?

7. George E. Smith says:

Why would you accept just 15% coverage as full coverage. Maybe 85% sea ice would classify as coverage; but 15% ice coverage is open water to me.

George

8. ak says:

Shouldn’t the ice be above normal given the lull that the Sun has been in and the low(er) temperatures experienced across the region this past winter? It seems weird that given those factors it’s still below the average.

9. Mark T says:

It seems weird that given those factors it’s still below the average.

Do you mean “it seems weird that it hasn’t immediately rebounded to above normal conditions in just 1 year“?

Sounds a little weird, actually, when you put it in this context.

Mark

10. Cassanders says:

@ak
Recall that there are still heat stored in the sea. IF the “large” areas of young ice continues to thaw slower than the previous years, I would think it is reasonable to look for connections to sun and air temperature.
(But as I have stated earlier, I think the interannual variation between ice area minima is more sensitive to wind and currents than thawing, per se).

Cassanders
In Cod we trust

11. Following years will have to take into account the area covered with ice over Canada..:)

12. John Galt says:

We have only tracked Arctic sea ice extent for 30 years. How do we have enough of a sample to know?

It’s only 30 years. That’s a lot in human terms, but that’s a meaningless fraction of the number of years since just the last ice age.

13. TERRY46 says:

Off topic but I just saw on Fox news where Antarctic ice is starting to break up and they don’t know why it’s happening but for sure of course it’s due to the warming.I didn’t think Antarctic mattered any mores???

14. Dr.Meir: Nansen uses a different algorithm to calculate the sea ice extent. The algorithms differ in the way combine the raw data together to estimate extent.
Perhaps I am too fool to understand, but, why the need of an algorithm?
Why not just a picture?…You know, those images taken by a thing called a camera..

15. RBerteig says:

I’m sure the choice of 1979 to some recent year as the span to average for comparison is based mostly on the fact that we don’t have any satellite-based coverage or extent measurements from any earlier than 1979. But what is the basis for assuming that this particular 20+ year period is long enough to cover all of the natural variation in the ice pack?

Isn’t it possible that recent low excursions are simply part of the natural variation and not an issue at all?

If we don’t know if the reference period is “normal”, it isn’t particularly honest to call excursions from it “abnormal” after all.

16. The approaching minimum will make things easier. At Boulder, new age scientists will measure ice deep from below :)

17. John H says:

That is peculiar that the NANSEN mean is higher than the NSIDC mean.
Makes no sense.

It’s good to have Dr. Meier accessible and so responsive.
Perhaps he stops in here on occasion.

So I have a few questions for him.

1) Why couldn’t, and hasn’t, the NSIDC adapted it’s mean from their current 1979-2000 mean to a 1979-2007 mean?

2) Will the Dr. acknowledge that in doing so would reduce the NSIDC mean?

3) With 30 years of record why are none of the most recent 9 years included in computing the mean?

4) Wouldn’t removing any 9 year period from calculating the mean make that mean a poor representation and basis for comparison?

18. Ed Scott says:

Risking the wrath of persons intent on directing the forces of Nature against me, I venture to say that the normal extent of Arctic sea ice is whatever it is at the moment. Persons with skins thinner than my Early Girl tomatoes and whose theme song might be Cole Porter’s “I’ve Got You Under My Skin,” might find fault with that observation. But as has been said, nobody disagrees that Nature is the norm.

19. Steven Goddard says:

Good questions. In winter the Arctic is dark; covered with clouds, and the ice is fractured and interspersed with open water. Visible wavelength photography is out of the question, so satellites use microwave data and organisations like NSIDC calculate the extent (area of the sea with greater than 15% ice concentration.)

20. George E. Smith (14:19:31) :

Why would you accept just 15% coverage as full coverage. Maybe 85% sea ice would classify as coverage; but 15% ice coverage is open water to me.

===============================================

You can use any number if you apply it consistently, so use 50% or 92% or 27% it will make little to no difference over the entire time series.

Please note that at the ice edge ice must reach several centimeters thickness before becoming translucent and rise above the surface as nilas, also in rougher water frazil condense until pressure forms cakes of slush that get pushed together to produce pancake ice. So 15% Coverage does not mean 85% Ice Free, means pancake or non dark nilas covering 15% of the area.

21. Walter Dnes says:

> Mike Bryant (14:08:47) :

> Also, I wonder if Dr. Meier would comment on why these side
> by side graphs are using different comparison years… 2007
> in Arctic vs. 2008 in Antarctic?

I think it’s because those are the record years of interest in each hemisphere. 2007 was a record low year for the Arctic ice pack. 2008 was a record high year for the Antarctic ice pack (not widely covered by the MSM; it goes against their AGW religion).

I have a question for Anthony or anybody else. Where on the NSIDC website do you find plottable data for the mean and current (or other) year? Rather than rely on the cramped graph at the IARC-JAXA website, I have a nice spreadsheet graph at home of IARC-JAXA data that fills my 24″ 1920×1200 monitor. I’d like to be able to reproduce the NSIDC graphs at home. Direct URLs to the data please. I’ve tried plowing through http://nsidc.org/data/docs/noaa/g02135_seaice_index/index.html and I sea stuff about monthly data, dailiy image files, and shapefiles. I want daily text data. Help.

22. Jim Papsdorf says:

Fox News just reported on the “Unexpected Eisdicke” study Anthony posted yesterday-it was brief but they mentioned that an expected ice thickness of 2 meters turned out to be 4 meters. The Goracle has a problem handling this one !!!!!!

23. Harold Ambler says:

Speaking of ice, I’ve done some more reporting on Catlin and interviewed Kenn Borek Air v.p. of operations Sean Loutitt regarding the eventual removal of the currently underfed expedition team members.

Story here:

24. Mike Bryant says:

Walter,
You said that 2008 was a record high year for the Antarctic ice pack… Here is the graph from CT:

Maybe I’m looking at it wrong, but it appears that 2007 was the record high for SH ice…

Thanks,
Mike

25. Just Want Truth... says:

” But something odd happened with the NANSEN data on December 13, 2008 ”

Does anyone know the whereabouts of James Hansen on the date in question? ;) jk

26. Just Want Truth... says:

NANSEN — Hansen, rhyming,…. hmmm, something’s up there… ;)

27. Looking at the Sea ice graphs that Anthony kindly displays on the RHS of his webpage can anyone provide a reason behind the persistent annual small “blip” in June? This appears to suggest a small regular annual increase at a time when ice is melting fastest. Quite strange.

28. Tom in Florida says:

The notorious base line of 1979 – 2000 cannot be considered normal. It is just an arbitrary reference period with no foundation for anything. We really do not know what “normal” arctic sea ice coverage is.

29. Mike Bryant says:

Another thing that seems odd… CT has the SH Sea Ice Area at 1,227,000 sq. km. ABOVE the 1979-2000 mean, while NSIDC has the SH Sea Ice EXTENT just barely meeting the 1979-2000 average. Now I know that area and extent are different but isn’t that a pretty big difference?

On the Arctic Roos, I know it’s the Arctic and not the Antarctic… however even though the area and extent ARE very different numbers, they are still each about the same distance from the mean…

http://arctic-roos.org/observations/satellite-data/sea-ice/ice-area-and-extent-in-arctic

Mike

30. David S says:

“What Is Normal Arctic Ice Extent?”

The earth spent most of the last half million years in an ice age. By that standard “normal” would mean ice covering most of Canada and much of the northern US. Under “normal” conditions the place where I’m sitting right now would be under 1/2 mile of ice. I think I prefer the abnormal conditions of the Holocene.

31. OceanTwo says:

From a statistical standpoint, I don’t see a real problem with -2000 instead of -2007. The data in that region is fairly consistent with little variation. Since the point of contention is the recent history (the last decade), it’s nice to have a control signal outside the area in question.

In addition, if you move the end points for the 79-00 readings, the average stays fairly consistent (and flat). ‘choosing’ end points close to the 2007 minimum (or even specifically choosing a certain point) can distort the results drastically. Whenever a signal is comparing specific results to itself, you have to be very skeptical of the results and examine the comparison very carefully.

I’ve seen quite a few graphs of this ice coverage data [media bias supporting the ‘polar bears are dying’ standpoint] which don’t go much beyond 2007 – even though we have quite up-to-date daily data – disingenuous to say the least.

It’s pitiful that whenever the facts don’t fit the premise they are summarily dismissed (as the antarctic data has) on a whim. It wouldn’t surprise me to see that the sea ice coverage doesn’t matter; it’s now the volume that’s monumentally important (data which can be distorted or massaged and thrown out with a “don’t bother with the boring details, you wouldn’t understand it: our top scientists have assured us we are all going to die”)

32. Leon Brozyna says:

Out of curiosity, I went back to the original story as covered here by Anthony on 13 December:

http://wattsupwiththat.com/2008/12/13/something-is-rotten-in-norway-500000-sq-km-of-sea-ice-disappears-overnight/

NANSEN’s explanation, which was later added to the post, seems weak as it cites changes from 22 October when in fact they began 11 September. It may very well have been a small error that kept compounding, though NANSEN never said that explicitly, but ever since then I’ve been a bit dubious about NANSEN. Dr. Meier makes a good point when he says, “The important thing to remember is that there is a good consistent record from the passive microwave data as long as you consistently use the same algorithm and the same processing.”

Personally, my favored source is IARC-JAXA. The comparisons this September should be most interesting.

33. Heat or no heat the maximum winter ice extent has no real significance in my opinion as the arctic is constrained by landmass. An increase in the ice extent/area as opposed to the last few years at maximum melt in mid september is what we want to see. In view of the reported increase in ice thickness and changed weather/circulation patterns in the arctic as opposed to the 2007 season this looks increasingly likely in my view.
Saying that ( fingers crossed ) we dont want to see too much of a dip in temperatures in the coming years – not good for nature in general and certainly not for us human saps. The alarmists are not worth dying for just to make a point – not that we have any control over anything anyhow.

34. ak says:

Mark T said “Do you mean “it seems weird that it hasn’t immediately rebounded to above normal conditions in just 1 year“?

Sounds a little weird, actually, when you put it in this context.”

Shouldn’t be all that weird really. Snow melt in mountains can be lengthened by a strong winter and cooler spring, likewise snow melt can be quicker and earlier if the conditions are warmer over the winter and spring. In some mountainous areas, snow can last well into summer months specifically because it’s on the northern slope and away from direct sun.

True, sea ice can last up to a few seasons – it’s rare in mountains for that – so it’s not a perfect analogy, but given the homogenous nature of the Arctic sea ice compared to mountain ranges, the analogy doesn’t seem all that far-fetched and it seems like cooler winters and lower sun energy would have a more widespread effect across the whole…

How long would you postulate the “lag” be for a “rebound?”

@Cassanders, there must be meteorological and current data available to compare from year to year?

35. aurbo says:

Moving the goalposts. That’s what the media does and their information is provided by, or filtered through various so-called science organizations.

This past year we’ve been hearing about how Arctic ice is on a steady decline which will inevitably lead to an ice-free summer in the very near future. In fact, the decline in relation to recent years ended in 2007. It has been coming back rapidly this past winter and spring. So what does the media do now?

They either continue to report on the 2007 ice year, or, if they have been told by a flood of e-mails pointing to the current data which has the ice on this date above the previsous high for this date back to 2003, the previous highest in this time frame. (In fact, yesterday, Apr 28th, the extent of Arctic ice as reported by JAXA was 245,000 km² above 2003 and getting very close to the 1979-2000 mean).

So does the AGW crowd concede? You’ve got to be kidding! They simply move the goalposts. Now they say that it is the ice volume that counts and most of the present ice is 1-year ice and the Polar ice sheet is much thinner than normal. Thus the ice volume is a lot lower.

But now we have the real measurements obtained this month by the Alfred Wegener Institute for Polar and Marine Research (featured in an article on WUWT a day or two ago) that measured the ice thickness with a sophisticated electromagnetic sensing device attached to a revamped C54 (DC3) and towed about 20m above the ice. Their route crossed the Pole and they ran several legs in various directions from the Pole. (I know, all of the routes ran southward, but at different longitudes). What did they find?

The first reports said that the ice thickness at the North Pole was about twice the amount they expected to find. Since the volume varies as the cube of the thickness, what do the AGWers do now. They’ve already backed the goalposts up to the grandstands.

The answer is bait and switch. They’ll probably shift their reportage to the Catlin expedition. This is a highly publicized trek by 3 grossly unprepared publicity seekers whose equipment failed early-on and any data they may have collected will be of little, if any scientific value. Nevertheless, they will be lionized by the media, especially the BBC a co-sponsor, for their daring and acumen as they dutifully report in regard to the ice situation that “It’s worse than we thought”.

As a matter of fact, if the AGW community had an emblem, their motto would be “It’s worse than we thought”.

Reply: Small point of correction. If you vary only one axis of a solid, ie the thickness and not the width or length, (just z, not x or y) the volume change would be directly proportional or simply double, not proportional to the cube of the variance. ~ charles the moderator.

36. Leon Brozyna says:

BTW – Steve, perhaps you could do a post to explain to everyone how the adjustments are made by IARC-JAXA in June & October. There was an explanation in a comment awhile back on an earlier sea ice post but I guess not everyone reads the comments.

37. JeffK says:

MarcH said…
“Looking at the Sea ice graphs that Anthony kindly displays on the RHS of his webpage can anyone provide a reason behind the persistent annual small “blip” in June? This appears to suggest a small regular annual increase at a time when ice is melting fastest. Quite strange.”

I’m glad you have seen this too. I brought this up on a previous thread a month-or-so ago bit it was never explained. I ‘seriously’ doubt the ice is actually doing what the graph is supposed to say that it is. Can someone please address this issue?

Thanks,
Jeff

38. PMH says:

OceanTwo (16:57:38) said “From a statistical standpoint, I don’t see a real problem with -2000 instead of -2007.”

Although this argument may be correct and there may not be a “real problem”, the more words required to explain the data the more the data should be questioned.

39. Wondering Aloud says:

ak

We don’t know how much of an effect the quiet sun should have, Lief thinks not that much it seems, but, it sure wouldn’t be large this quick. Thermal inertia is huge and input change small.

40. steve says:

Hey Anthony,

I know this is completely off topic but I had a discussion a while ago with a guy called Foinavon (I think) about climate’s sensitivity to CO2. I think it was to do with Hansen having nailed the sensitivity/gain, g, to 3.

One of the papers I referenced was by John Christy and was, at the time, not published, hence Foinavon was not interested. Apparently this has now been published and is available to view at http://www.nsstc.uah.edu/atmos/christy_pubs.html.

It seems quite interesting as it purports to show that CO2’s forcing has no feedback. I.e. a doubling of CO2 leads to at most 1 degree C rise in temperature or that if there is a positive feedback mechanism it must be balanced currently by an existing negative feedback. The negative feedback cannot be due to aerosols, as the IPCC claims, because of Chylek(2007)

These results puts CO2’s forcing well below all existing models and well below any disaster scenario.

Cheers
Steve

41. aurbo says:

Re my prior comment:

Charles: You’re right, I should have kept the x and y axes constant leaving any change in the z axis directly proportional to the volume.hat was I thinking?

42. AnonyMoose says:

Notice that if you look at the values of the averages for now, they both are 14 million square kilometers. But the current values are quite different. If one value is presently larger, the average should also be larger unless what they’re measuring happens to be currently affected by the differences.

43. AnonyMoose says:

Incidentally, in our current glacial averages, “normal” extent might actually be around London or Manhattan. :-)

44. drmike86 says:

MarcH & JeffK

I believe the little blip on the chart was identified as a period when they change to a different filter on the satellite. It was on a previous thread.

Mike86

45. Robert Wood says:

Aron @14:12:47

Being as the Grauniad is a British rag, that should be “… stick your two fingers up to them”.

46. KipHansen says:

Steven,

Have I missed something here?

Has there been some reasonable explanation of the data differences as seen in the blink comparator or not?

Clearly NANSEN and NSIDC are different data sets and shouldn’t be expected to exactly track, but when a public data set changes that radically – someone has some explaining to do.

Has no explanation been forthcoming in the last four months?

47. WestHoustonGeo says:

Quoting:
“This is a bit off topic, but I thought you should see it. Re the assumptions of AGW Truth!!! Look at this drivel–especially the chart.
http://www.sciam.com/article.cfm?id=limits-on-greenhouse-gas-emissions
Commenting:
That sort of thing, my friend, is why I cancelled my Scientific American subscription after 30-some years of loyal readership. I encourage others to do likewise.

48. aurbo says:

Re the rapidity of ice melt. First, at this time of year, the ice melts from below.
The rate of melt depends on two major components. The temperature of the water and the speed of the ocean current across the base of the ice.

For the most part, the temperature itself is related to the rate of flow of the ocean beneath the ice which determines the advection of warmer waters either horizonatlly or is some cases vertically especially near the boundary layer. When the ocean current is high the melt rate increases, when the current subsides to near calm, the water adjacent to the base of the ice quickly comes to equibrium with the ice and melting proceeds very slowly. If the current increases, the surface layer of near freezing temperatures is mixed both horizontally and vertically and the rate of ice melt increases.

It’s all about the conditions of the ocean near and in contact with the ice.

As for the presence and extent of open water, there is nothing new about that. Open water near the Pole, even right at the Pole has been observed frequently in the past. Submarines have surfaced on many occasions at the Pole going back to the first such incidence back in 1958 with the first atomic submarine, the Nautilus. Wide leads and polynyas have been observed frequently near the North Pole even in the Winter.

Most importantly, historic records of undersea as well as surface vessels show that there is nothing unusual about the character of Arctic ice conditions for more than half a century.

49. Eric Chieflion says:

Mark Twain once said, or so I seem to remember,
“There are liars; damn liars; and statisticians.”

So when New York is covered with an ice sheet, will we be debating whether it is a mile thick or a kilometer?

I must add, however, that I respect Dr. Meier for his prompt, courteous response. Science is ever an evolutionary process, at least if scientists are willing to listen to well-thought out but contrary opinions. I seem to remember that the Einstein-Bohr debates ended with Einstein saying, “I cannot accept your position, but I cannot refute it.” Neither one thought the science settled. When Bohr died in his sleep (several years after Einstein), it was discovered that the night before he had been working in his study; on his blackboard were equations relating to his debates with Einstein. (Sorry, it’s been many years, and I don’t remember the references or have the time to look them up).

When science and politics meet, you get strange brews.

50. the1pag says:

Here’s an item from today’s “best of the web today” by the Wall Street Journal’s Jim Taranto:
<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>
Global Warming on the Rocks

Al Gore said Tuesday the world must act quickly to slow the melting of the world’s polar ice packs and glaciers before it reaches a critical rate for global warming.

But it turns out the world acted very quickly indeed, as Germany’s Radio Bremen reports (translation here):

The research aircraft “Polar 5” today concluded its Arctic expedition in Canada. During the flight, researchers measured the current ice thickness at the North Pole and in areas that have never before been surveyed. The result: The sea-ice in the surveyed areas is apparently thicker than scientists had suspected.
Normally, newly formed ice measures some two meters in thickness after two years. “Here, we measured ice thickness up to four meters,” said a spokesperson for Bremerhaven’s Alfred Wegener Institute for Polar and Marine Research.
Is it possible that global warming is neither a catastrophe waiting to happen nor a fraud but merely the result of confusion induced by the metric system?

Question– did they mean the “feet” thickness instead of “meters”? Looks like it’s getting thicker, anyhow.

Pag

51. bsneath says:

“But something odd happened with the NANSEN data on December 13, 2008. Overnight it lost about 500,000 km2 of ice,”

It is possible that there is an undetected error in the data that needs correcting. (I’m thinking Siberia…………….)

Whatever it is, it should be investigated, explained and corrected if necessary. I honestly would think that scientists involved would want to do this to protect and preserve their credibility. There are simply too many cracks forming in the AGW foundation to withstand the vibrations of many more “steamrollers”.

52. Bill Illis says:

I think they continue to use the 1979 to 2000 average because that period was chosen the last time they went through all the data thoroughly and checked each day.

In addition, there is some stability overall in this time period, some ups, some downs but reasonably close to an average. Starting in 2000, the extent started to go down and since they wanted to measure a decline due to global warming, they stayed with this average period.

The final, perhaps unfair, potential explanation is they don’t have enough time to thoroughly go through every day again and verify the data and they don’t have time to extend the data back to 1972 which is when the actual satellite data begins. Yes, I am not a fan.

Fortunately, it can be done.

So here is today’s Northern Hemisphere Sea Ice Extent versus the average from 1972 to 2009.

April 28th, 2009 – day 188 (due to the leap years) – is the 12th lowest sea ice extent (out of the 26 years).

It is 438,000 km^2 below the average for this date (but rapidly gaining).

Here is what the complete daily series since 1972 looks like.

53. Bill Illis says:

Sorry, that should be 418,000 km^2 below normal on April 28th – Day 118.

54. Squidly says:

George E. Smith (14:19:31) :

Why would you accept just 15% coverage as full coverage. Maybe 85% sea ice would classify as coverage; but 15% ice coverage is open water to me.

George

George, I have often wondered the same thing, but then it dawned on me, if they use 15% now, they can adjust that to 25% later and paint a worse picture, then 35%, 45%, 50%, … ratchet it up as they need to in order to keep the hysteria flowing, move them thar goal posts again. In 10-15 year time, they will be able to say that sea ice extent has disappeared completely, as they will then be using 125% coverage as a meter.

55. Squidly says:

ak (14:21:42) :

Shouldn’t the ice be above normal given the lull that the Sun has been in and the low(er) temperatures experienced across the region this past winter? It seems weird that given those factors it’s still below the average.

Not strange at all, in fact, this precisely explains why air temperature is not the primary driving force behind the Arctic sea ice extent, but rather ocean currents and air currents. In your question, you illustrate perfectly one reason why the AGW crowd is so blatantly wrong when assessing and predicting Arctic sea ice behavior (you know, evaporation and all).

56. Why don´t you send some of those Global Warmers/Changers to preach and reeducate Al-Qaida people. Their persuasive and pervasive speech will make change their minds or convince them it is useless to make any harm to America after they realize than their wildest terrorist goals have been already achieved and surpassed by them.

57. WestHoustonGeo (18:32:40):

Quoting:
“This is a bit off topic, but I thought you should see it. Re the assumptions of AGW Truth!!! Look at this drivel–especially the chart.
http://www.sciam.com/article.cfm?id=limits-on-greenhouse-gas-emissions”
Commenting:
That sort of thing, my friends, is why I canceled my Scientific American subscription after 30-some years of loyal readership. I encourage others to do likewise.

I cancelled my subscription to Scientific American five years ago due to the publication of an article about an ad infinitumechoed universe . Heh!

58. KimW says:

Report from the Arctic Council,

“I am deeply grateful to Nobel Peace Prize Laureate Al Gore for reporting to the Arctic Council today from yesterday’s conference on melting ice. His intervention and the presentations by leading scientists yesterday confirm that the ice is melting even faster than previously imagined, both in the Arctic and in other regions of the world. This makes it all the more urgent that we address the issue of climate change, and we will convey our sense of urgency to the UN Climate Change Conference in Copenhagen in December 2009,” said Mr Støre.”

Nice to see that they listen to a former politician with vested AGW interests rather than the scientific results. I think that Copenhagen 2009 will be a lovefest of AGW alarm – get committments and grants before the big freeze sets in.

59. Robert Rust says:

“ak (14:21:42) :

Shouldn’t the ice be above normal given the lull that the Sun has been in and the low(er) temperatures experienced across the region this past winter? It seems weird that given those factors it’s still below the average. ”

The warmist tell us that the sun plays no role whatsoever. I think many skeptics say the same thing, actually. So, I’ll be interesting to watch if the sun is now blamed for AGW taking a breather. Somehow – in their pretzel twisting ways – they’ll be able to see clearly how increased sun activity had no role in warming the planet – but it’s solely to blame when the planet’s temps take a dive.

60. Fluffy Clouds (Tim L) says:

Any one want to Bet that the 2009 line never passes the average line?
I bet it will do the magical drop like it did 12/11/2008?

61. Mike Bryant says:

Wow Bill Illis,
That was alot of work, and I appreciate it…
Mike

62. Um…y’all are missing the basic point. Someone needs to print-out a nice poster-size plot of the global ice exceeding the average for the last 30 years…I don’t care whose average (mean) you use…and ship a copy to the EPA, Al Gore and the IPCC and say: “..’splain this …how can the climate be warming if the ice keeps growing?”

63. Robert Austin says:

How ironic will it be if the Catlin expedition survives and completes its mission due to the Arctic ice being uncooperative and not melting from beneath its feet.

64. deepslope says:

Bill Illis (19:00:43) :

great data sets, thanks, Bill, for all that diligent work!

65. Len van Burgel says:

MarcH and Leon Brozynow:

Re the June uptick on JAXA ice extent graphs I posted this on two threads a week ago:

After speculating (wrongly) that it was an instrument sensor drift, I emailed JAXA and got this reply which I also posted on a previous topic (“leaving the icepack behind”)

Dear van Burgel,

Thank you for inquiring about our AMSR-E sea-ice monitor web.

You are right.

Current version of data processing makes an erroneous bias of
sea ice extent on June 1st and October 15th which are seen
in the graph of sea ice extent as a small peak on these dates.
The apparent bias arises due to a switching of some parameters
in the processing on both dates. The parameter switching is
needed because the surface of the Arctic sea-ice becomes
wet in summer due to the melting of ice which changes
satellite-observed signatures of sea-ice drastically.

We are planning to improve the processing to make the gap
much smoother in the coming year.

Sincerely,

Masahiro HORI
Japan Aerospace Exploration Agency (JAXA)

NANSEN’s Dr. Meier says, “The important thing to remember is that there is a good consistent record from the passive microwave data as long as you consistently use the same algorithm and the same processing.”

This responce doesn’t really address Mr Goddard’s central point.

If both organisations have been consistent they may well have different averages from different algorithms ( I will never hear that word in the same way again – Yuk!) but the NANSEN current figure should still be closer to their average than NSIDC is to theirs.

Or am I missing something?

67. Thanks Len van Burgel, I will look out for the “Blip” in June to see if there has been an improvement.

68. Antonio San says:

Bill, at a time of computers and significant data searching capabilities including good old summer students grind, chosing the 1979-2000 average is simply an undefendable position for a serious scientific department, especially when on other datasets, they are willing to use the climatology widely accepted arbitrary 30 y average. The fact that they do it on this particular dataset and it suits their well publicized bias – Mark Serreze at least is unapologetic about it- is even more unacceptable. If you could do it, they could and should. Period.

69. Frederick Michael says:

Fluffy Clouds (Tim L) (19:46:10) :

Any one want to Bet that the 2009 line never passes the average line?
I bet it will do the magical drop like it did 12/11/2008?

I’ll bet you it doesn’t do any magical drops.

70. Yes, thanks, Bill. Kudos* to thee!

Note: there is no such thing as a kudo. Kudos is a singular noun, like praise.

71. Robert Rust (19:38:20) :

“ak (14:21:42) :

Shouldn’t the ice be above normal given the lull that the Sun has been in and the low(er) temperatures experienced across the region this past winter? It seems weird that given those factors it’s still below the average. ”

The warmist tell us that the sun plays no role whatsoever. I think many skeptics say the same thing, actually. So, I’ll be interesting to watch if the sun is now blamed for AGW taking a breather. Somehow – in their pretzel twisting ways – they’ll be able to see clearly how increased sun activity had no role in warming the planet – but it’s solely to blame when the planet’s temps take a dive.

The atmosphere and the oceans are open systems and, as open systems, they have boundaries with external systems, i.e. the atmosphere and the oceans are not isolated systems. Centering on the atmosphere as a thermodynamic system, it’s a general rule that the interchange of energy and matter between the atmosphere and the external systems is always active and that the internal climatic components of the atmosphere respond -negative and positive feedbacks- to any change of the external systems, whether that change is minuscule or large. Deductions are considered from measurements of thermal processes, not from correlating graphs.

And I’m not considering our inability to work the heat storage by oceans out and our failure for obtaining consistent information on long term changes and small variations. So I think you’re right on your estimation about the biased AGW arguments.

Using the 1979 to 2000 period doesn’t make much of a difference – its just an average to compare against.

Is a 30 year period better? I would think that would only be true if it encompassed whatever the period is that encompasses a full cycle of arctic ice variability. Since we don’t know what that period is, 1979 to 2000, arbitrary as is clearly is, is as good any other.

For all we actually know, the cycle could be 40 years, or 20, or 60. My guess would be 60, based on the PDO. But that’s still a guess and irrelevant since we don’t have 60 years of data.

73. Leon Brozyna says:

Len van Burgel (20:35:20)

Thanks for reposting that response. This is one of those FAQ’s that will keep coming up from time to time as new readers come to WUWT. And will doubtless keep on coming up in the months ahead, probably most anytime there’s a discussion about sea ice.

74. An Inquirer says:

Yes, as Dr. Meier points out, it is poor science to “mix and match products” in making a graph. However, it is good science to check a variety of sources and approaches to see if your trend is robust over a number of analyses.

75. Mark says:

Why does the NSIDC continue to calculate the mean up to 2000? This makes the later trend lines look farther from it than if they calculated the mean up to 2008.

76. John F. Hultquist says:

Paul (14:16:49) : Just out of curiosity, why doesn’t NSIDC use the 1979-2007 average?

An international agreement has most countries reporting “normals” or averages using 30 years of data with the final year ending in “0”, such as 1990, 2000, 2010.

77. John F. Hultquist says:

Adolfo Giurfa (14:38:48) : why the need of an algorithm?

The camera is a sensor that records a “signature” in numbers based on the wavelengths reflecting off of the surfaces (note the plural). Something has to convert all those numbers into something recognizable and reportable as ice, water, tundra or whatever based on what you are taking a “picture” of. That something is an algorithm.

78. Before someone says that I’m rejecting correlation graphs, I must say that correlation graphs are useful instruments for identifying and interpreting variables because graphs are visual representations of real data. Unfortunately, if the databases or the algorithms have been flawed, the correlation graphs will be flawed also. The latter has been demonstrated many times here, in WUWT.

79. Richard111 says:

As the days, weeks, months, years go by they keep “adjusting” the data but the temperatures keep falling. What are they trying to achieve?
Just look at current NH snow cover. I forcast a cool summer and a colder winter than last year.

80. John F. Hultquist says:

Has anyone ever wondered about the choice of years for averages or normals of climatic variables? In case you have but haven’t found the answer, here is one:

“Climatologists define a climatic normal as the arithmetic average of a climate element such as temperature over a prescribed 30-year interval. The 30 year interval was selected by international agreement, based on the recommendations of the International Meteorological Conference in Warsaw in 1933. The 30 year interval is sufficiently long to filter out many of the short-term interannual fluctuations and anomalies, but sufficiently short so as to be used to reflect longer term climatic trends. Currently, the 30-year interval for calculating normals extends from 1971 to 2000.”
http://www.aos.wisc.edu/~sco/normals.html

81. vg says:

What the heck is going on? This was posted by S Goddard just last week
http://eva.nersc.no/vhost/arctic-roos.org/doc/observations/images/ssmi1_ice_area.png. Quoting this graph, he said that NH ice was back to normal limits 1SD. So is it now a fact that Norsex has again lowered the WHOLE 2008and 2009 graphs or increasecto make it appear that NH ice is still below normal the mean graph? (as I warned many time already and recorded here
. If this is so NORSEX must be a 100% junk site (NORSEX) because neither AMSR, CT, NSIDC or DIM have changed. It appears to be run by one person so check before you believe.

82. John F. Hultquist says:

If you go north of the Arctic Circle during the NH winter there is very little sunlight and for much of it none. So whether or not the Sun is in a “lull” would seem to make no difference. This lack of sunlight within the Arctic extends back in time for each and every year – so the average is not going to be directly effected. The Arctic basin is like a gigantic toilet bowl with rotation, tides, currents, and wind. When these things combine in certain ways the flush is on and the ice clears out and melts at lower latitudes. When rotation, tides and so on do not effectively clear the ice out, it stays and thickens and grows older. Just because Gore and Waxman and others think the ice melts/evaporates and exposes the tundra doesn’t mean we skeptics should.

An average is easily skewed by a few extreme values. Example, the average wealth of folks in King County, Washington State – Bill Gates and other Microsoft billionaires live there. Most folks are well below the average and have no hope of getting close. That’s why some things are better compared to a mode or a median. If you like playing with numbers look at each of the years of ice extent and see if some were not quite large. That would explain why the current year is still below average.

83. Just Want Truth... says:

Bill Illis (19:00:43) :

Thank you for the numbers and the graphs Bill. I didn’t know data was available back to 1972. We always hear 1979. I can see there isn’t much of a difference between the 70’s and now.

I liked reading your view on PDO yesterday too. You said you were hesitant to write about. I don’t know what anyone else thinks about it. But I just want truth. I was fine with reading what you had to say. It was interesting– did you like Columbo in the 70’s? ;)

84. Jack Green says:

[snip, while there are few limits on what you can say about Hansen, please be more respectful of Dr. Meier who contributes his time to posting here]. ~ charles the moderator

85. [blockquote]
Paul James:
“nearly large enough to place California inside”

YIKES !!!

Ring the alrm bells !!!!

Has any one told Mr Waxman that CA was moved North and then apparently melted ? Or did it evaporate ? I always have trouble keeping those two in order.
[/blockquote]

Well, that would explain why my condo is under water.

86. .
>>Heat or no heat the maximum winter ice extent has no real
>>significance in my opinion as the arctic is constrained by landmass.

But thickness and continuity may be a factor. If most ice is destroyed by wind and flushing, rather than melting, then the ice’s resistance to wind and tide may be a crucial factor.

If the ice is contiguous and strong, it may resist wind flushing. If it is weak, it may be flushed easily. So you might have a situation where the thickness reaches a ‘tipping point’ (sic) of weakness where great swathes of it is flushed out of the Arctic ocean (2007 and 2008), whereas if it was a little more contiguous and robust it would resist this (2009) and much much more ice will stay in the Arctic.

This would result in huge differences in summer ice extent, for only small changes in temperature.

Ralph

87. >>Question– did they mean the “feet” thickness instead of “meters”?

The Germans using ‘feet’? You do jest, surely?

No this was 4 meters thick – quite thick indeed.

Ralph

88. Jack Green says:

Sorry Charles the moderator but you should have just snipped out the Mx#!?r part and not the whole post. These Hansen/Gore alarmists are scaring people to gain power. Consider editing my post removing my mention of the nice guy Mx#!?r. It’s obvious with this Ice Extent manipulation that these groups are working the answer backwards to a conclusion that fits the story that CO2 the problem.

Reply: I considered that, but it would have required an editorial rewriting of your post to make sense and that is not really an option. ~ charles the moderator.

• charles the moderator says:

Jack Green:

Just so you won’t feel singled out, I’m going to bed, so any further comments may not be approved until one of our East Coast moderators comes online or one of our early morning old folks on the West Coast.

89. Robert Bateman says:

4) Wouldn’t removing any 9 year period from calculating the mean make that mean a poor representation and basis for comparison?

If the last 9 years have cooled, would it make sense to include them if the objective was to continue to parade the old data which effectively portrayed rapid warming?
It’s also a good way to hide the cyclic nature of the ice.

90. Richard Hobley says:

Perhaps the algorithm has an inbuilt routine to keep the extent out of the STD region. Was not doing it’s job – a quick tweak will soon fix that. Can’t have people thinking there is anything “normal” going on up there!!

91. Steven Goddard says:

vg,

NANSEN tracks both ice extent and area. They show area in the normal range, but not extent.

92. JamesG says:

On thing this does tell us is that soot landing in the Arctic isn’t apparently too significant. Dr. Meier was right on that point I admit. And Hansen is therefore wrong again alas: I had been thinking that was the one thing he managed to get right. But no! Clearly much of what is called climate science is mere guesswork.

93. John H. says:

>Nansen uses a different algorithm to calculate the sea ice extent.

Ok, am I missing something here? This is purported to be science, right?
If you change the algorithm for one year, you need to recalculate every year to get a new average. If you keep an average with an old algorithm for 27 years and begin a new algorithm then you can not even pretend the new years data will even be relevant to compare to any previous year.

I’m sorry, I’m just beside myself. I do not know how to comprehend this stupidity.

94. Bill Illis says:

So, here is today’s numbers.

Day 119 – April 29th, 2009 – 13,160,000 km^2 from Jaxa

– 12th out of 38 years.
– highest extent in 8 years.
– 2001 was the last year above 2009 and it is substantially above, won’t catch up for a long time.
– 2009 is above 1989 however, 20 years ago.

– 431,000 km^2 below the 1972 – 2009 Average (versus 428,000 yesterday).
– 481,000 km^2 below the 1979 – 2000 Average (NSIDC’s chart looks to be about half this number but I don’t know what they are using now – thanks for telling us. This number, however, is closer to the Cryosphere Today’s number and Nansen’s chart.)
– 82,000 km^2 below the Standard Deviation of the 1979-2000 Average.

95. Pamela Gray says:

Early morning old folks out West!?!?!?!?!?!? I resemble that remark.

96. Pamela Gray says:

I also agree about the PDO versus other oscillations regarding Arctic ice events. The PDO forms the lion’s share of on-shore weather pattern variation from West to East. With a shifted jet stream North, (and possibly more volatile and loopy), the PDO keeps me up to date on possible weather in coming months. As for Arctic ice events, it seems to me that the AMO couples more with Arctic ice events.

97. Steve M. says:

Why would you accept just 15% coverage as full coverage. Maybe 85% sea ice would classify as coverage; but 15% ice coverage is open water to me.

George

Considering that 85% of ice is below water, 15% coverage sounds reasonable. I wouldn’t want to captain the Titanic through and an ocean with 15% sea ice.

98. John F. Hultquist (22:18:51) :
I know it perfectly, but a massaging algorithm is the one to adjust reality to wishes. Chances are that they zip it as much as it is possible in order to not be blamed of deniers by the people who pay their salaries.

99. John G says:

I don’t understand Dr. Meier’s explanation. If the ice extent means calculated by NSIDC and NANSEN differ so much from what would be expected because the algorithms used and treatment of data differ between the two groups why does the current 2009 extent estimate to this point match perfectly? Is this just a freaky year in which the different algorithms etc. happen to produce the same results or am I missing something?

100. vg (22:53:23) :
What the heck is going on? This was posted by S Goddard just last week
http://eva.nersc.no/vhost/arctic-roos.org/doc/observations/images/ssmi1_ice_area.png. Quoting this graph, he said that NH ice was back to normal limits 1SD. So is it now a fact that Norsex has again lowered the WHOLE 2008and 2009 graphs or increasecto make it appear that NH ice is still below normal the mean graph? (as I warned many time already and recorded here

Unfortunately for your agenda it didn’t happen! What actually happened to the Nansen graph was that because of an error the data on their lower graph where it is plotted along with the mean was not correct, this was noticed because the upper graph (which should be exactly the same) was different. The error was corrected and the data plotted on the lower curve then matched the correct data that had always been on the site!
Ever wonder why Goddard only showed the plot that changed and not the other one? Another guy with an agenda.

Here’s the change in the actual data curve that should have accompanied the one shown by Goddard above:

101. ralph ellis (01:23:57) :
.
>>Heat or no heat the maximum winter ice extent has no real
>>significance in my opinion as the arctic is constrained by landmass.

But thickness and continuity may be a factor. If most ice is destroyed by wind and flushing, rather than melting, then the ice’s resistance to wind and tide may be a crucial factor.

If the ice is contiguous and strong, it may resist wind flushing. If it is weak, it may be flushed easily. So you might have a situation where the thickness reaches a ‘tipping point’ (sic) of weakness where great swathes of it is flushed out of the Arctic ocean (2007 and 2008), whereas if it was a little more contiguous and robust it would resist this (2009) and much much more ice will stay in the Arctic.

So far this year the outflow through the Fram has been strong, if anything stronger than at the same time in 2007.

Examples:

This is one reason why the current extent is not dropping very fast, there is so much ice flowing out into the Atlantic. If this is correct then the ice remaining in the Arctic is being weakened with significant consequences for later in the year.

102. Jack Green says:

Charles: I’m just picking on you. You guys do a great job. Dr Meier is a real pro and it’s nice to have his attention. At least he’s using the “peer review” that we all provide. Thanks. I’ll think before I post again. This Ice data “algorithm” language is just another “forcing function” adjustment factor.

103. Steven Goddard says:

Phil,

You are the one with the agenda, and you made no attempt to explain the point of this article, why is why the ratio of NANSEN current/mean is significantly lower than the ratio of NSIDC current/mean – when it should be the other way around.

You also missed the fact that in Anthony’s original article (linked to in this one) Stein Sandven at NANSEN gave an explanation for why they changed the graph. His explanation did not give any insight into the question I am raising in this article, and your accusatory nature and non-sequitur response also does nothing to shed any light.

104. Sergio da Roma says:

I generally observed a discrepancy between total sum of the artic ice regional area and the total area reported in the site “cryosphere today”. The summed areas are about 300000 or 400000 kmq wider in comparison to the official total area. Could somone explain me something about that?

105. JAN says:

vg (22:53:23):

“It appears to be run by one person, so check before you believe.”

[I would like to point you to this article I found today in the net pages of the biggest Norwegian dead trees daily; VG:

http://www.vg.no/nyheter/utenriks/klimatrusselen/artikkel.php?artid=542650

From the article (my translation):

“Climate Scientist: Ice Free Arctic by 2100

BERGEN (VG): The experienced climate scientist Ola M. Johannessen (70) was baffled when he calculated when the Arctic Ocean will be ice free year round.

“- It shows, if we put the numbers into that formula, that we are going to have an ice free Arctic – summer as well as winter – already in this century”, says Johannessen.

Now, it is not just any kind of formula the Research Director at the Nansen Center for Climate Research has developed.

He has compared the annual ice extent in the Arctic Ocean with the annual concentration of CO2 in the atmosphere.

AND THE RESULT IS FRIGHTENING:

“In the beginning of the century we have some natural variations we cannot account for. But the last five decades there is a very strong statistical correlation between the measured CO2 concentration and the actual measured ice extent.”

BAFFLED

“Yes, if we put the graphs of the ice extent and the CO2 content on top of each other – then the connection is apparently striking.”

“- I was certainly quite baffled when I saw it,” says Johannessen to VG.

His analysis shows that the increase in CO2 alone may account for as much as 90 per cent of the ice decline in the Arctic.

On this basis, he has simply been able to construe a formula which suggests how much a given increase in CO2 content in the air affect the ice extent. Thereby he can simply enter both values into the formula on his PC, and look at when this formula says there is no more ice left:

“- If we use my statistic formula, all ice will be gone, even in winter, when CO2 concentration in the atmosphere reaches 765 parts per million (ppm). Today the concentration is about 385, but 765 will most probably be reached by year 2100, if we don’t execute drastic cuts.”

Photo captures (top): “Arctic – without ice. If the shocking calculations of research veteran Ola M. Johannessen is correct, Arctic will be without ice by year 2100. Summer as winter.” (bottom): “WARMER: During the last ten years sea level has risen by about 3 centimeters.”

Anthony, I don’t know if this is the right thread, but I think this deserves some attention. It looks like we have another contender for the prize of the boldest ice prediction for the Arctic.

We have previously Dr. Serreze with his prediction of an ice free North Pole in the summer of 2008. Then we have big Al with his prediction of an ice free Arctic by 2013.

However, I think Johannessen is in a class of his own. Please notice, he not only predicts an ice free Arctic in summer, he predicts an ice free Arctic in WINTER.

It is conceivable that an ice free Arctic in summertime may occur if the atmosphere and the oceans warms by a few degrees C. This has probably also happened earlier in Holocene, according to archeological evidence. However, in the wintertime, there is bitter cold and darkness 24/7 all over the Arctic for the good part of 6 months. Thanks to the invaluable research efforts by the Catlin Arctic Survey team, we now know that temperatures in the Arctic, even in March/April, are between -25 and -40 degrees C. How is a doubling of CO2 concentration going to increase temperatures enough to avoid freezing of sea water in Arctic winter?

According to reasonably accepted science, a doubling of CO2 will increase temperatures by about 1.2 C, give or take a few tenths. Even if we accept the baseless and highly unlikely assumption of a climate sensitivity of 3, the temperature increase will not be more than 3.6 C. So how exactly is this temperature rise going to stop water from freezing in the Arctic during the 6 months of winter temperatures below -20 or -30 degrees?

What this exercise in statistical extrapolation shows, is how absurdly out of reality it is possible to end if you just extend short time trends to infinity.

Anyone who thinks he can up the predictions even more?
Do we have a winner?]

The article presents this guy as the Research Director at the Nansen Center, but whether he is responsible for the NORSEX graphs I don’t know.

What do you think, just another guy with an agenda?

106. geo says:

Looking at amsr-e, it strikes me that for a good while in May last year 2008 was better than even 2002 and 2003, but then tanked in August and September, in part no doubt due to the “first year ice” phenomenon.

Right now, 2009 is even better than 2008, 2002, and 2003. Right now.

I think it is going to be very interesting to see how it does in August and September this year. If the NSIDC (much maligned) claims about “second year ice” hold true, then I would expect the 2009 summer minimum to end up better than 2008 but not as good as 2005. On the other hand, if 2009 improves on the 2005 minimum that would be a real milestone worth a little chest-pounding and would be quite interesting to see what tack the AGWer’s would take in explaining it.

And if 2009 can beat 2003, then yippee and stfu about arctic ice in “crisis” for awhile.

But I’m somewhat conservative. I think second year ice does matter at least a little. Not as much as first year ice, but some. I think we’re going to end up well above 2008, and in the ballpark of the 2005 minimum, but I’m not willing to predict if it will be a little above or a little below.

107. zonko says:

Very interesting!

108. Juraj V. says:

JAN, this is utterly unbelievable. Whatta scientific method! I saw a graph relating global temperatures to Iceland population and its regression was R=0,98 maybe.
Recently I read pretty cool sentence: “mainstream science is on the verge of being overturned by the efforts of a group of dedicated amateurs” (The Australian Financial Review, April 23) – so lets roll!

109. vg says:

S Goddard my silly… should check myself LOL

110. JAN says:

Sorry, vg

No pun intended!

111. h.oldeboom says:

What is the scientific value of the Catlin expedition compared with the value of the very recent Alfred Wegener instite DC-3 fligt across the polar area? In a relatively short time the DC-3 did a huge amount of measurements compared with the restricted amount of measurements of Catlin and the surveyed distance/area of AW was much longer/bigger. The fact, the DC-3 measurements have been done in a very short time gives me the feeling, that these measurements gives at least a better idea of the general ice thichkness situation because Catlin needs to much time and in this long time too much natural changes can happen in the ice situation.

112. Vincentvoll says:

Conclusion’ cadre displaying the vindication of that’s proven.

113. geo says:

The scientific value of Catlin? Scientists got paid. You can’t have scientists without figuring out ways to get them paid. Grants got granted. Paper shufflers got to shuffle paper. Websites were hit and newspapers were sold. Heck, a grand old time was had by many!

Seriously, re that comparison it would be interesting to know the lead times on the two projects as to planning and approval. Probably the Catlin people had no idea of the other project.

114. Earle Williams says:

The Catlin expedition had the potential of being a very useful adjunct means to calibrate / verify the Wegener Institute airborne study. Any time you can ground tructh an airborne survey your greatly increase the confidence and value of the data collected from the air.

Imagine having a 300 km or greater transect of the ice thickness using ground penetrating radar. And this transect has been calibrated with numerous aurger measurements along the line. If you flew an airborne line along the exact same path as the surface transect you would have unimpeachable calibration data to supplement the interpretation of the EM results.

It seems that providing useful quantitative scientific data was not the primary mission of the Catlin expedition. That is truly unfortunate.

115. That’s interesting to see the 1979 – 2007 average. But it would be interesting to see the entire range of positions as a time series.

116. bill says:

h.oldeboom (13:17:59) :
What is the scientific value of the Catlin expedition compared with the value of the very recent Alfred Wegener instite DC-3 fligt across the polar area? In a relatively short time the DC-3 did a huge amount of measurements

The radar measurements are very inaccurate:
Top right corner of PDF gives comparison

Errors often 25cm and up to 1metre in the short comparison given. Would you trust this data?

117. Earle Williams says:

bill,

Neither of these instruments use radar. The graph you refer to compares thicknesses calculations for the airborne vs. the “ground based” electromagnetic conductivity instruments. There is no ice auger thickness to decide if one or both of the measurements are in error.

The size of the EM bird vs the ground based EM31 account for some of the observed difference. One is measure thickness over an approximately 2 m diameter circle whereas the other is measuring thickness over a 4 m diameter circle. Variance between the two instruments is to be expected.

The good correlation with EM31 does vouch for the methodology and instrumentation. If I were reviewing a report or publication I would insist on seeing several calibrations against ice of known thickness. The difference between the two instrument measurements suggests that there may variations in conductivity within the ice such as cracks or inclusions of brine or seawater.

118. Shouldn’t the ice be above normal given the lull that the Sun has been in and the low(er) temperatures experienced across the region this past winter? It seems weird that given those factors it’s still below the average.

Things take time to heat up and cool off. Big things take longer.

Heat transfer in a nut shell.

119. pkatt says:

Pardon me, but on cryosphere arent we seeing the same weird stretches of open water we were when the satelites were screwing up? How is it we can trust the data we are getting?

120. pkatt (16:56:10) :
Pardon me, but on cryosphere arent we seeing the same weird stretches of open water we were when the satelites were screwing up?

No.