UPDATE: Dr. Walt Meier of NSIDC writes in with some information, seethe end of the article.
I’m getting weary of answering this question in comments, so here it is front page. Note the little bump right about June 1st.
Rick W asks:
Can anyone explain the upward bump in the sea ice extent that seems to occur each June? Apologies if previously covered.
Answer:
This is a seasonal adjustment to compensate for meltwater on top of the ice, which would ordinarily be viewed as “open water”. Right about now, the Arctic sea ice gets melt pools forming on the surface. If these are not compensated for, sea ice extent will read artificially low.
That being said, I wonder why we don’t see the same adjustment at NSIDC:
I don’t know the answer, but it could be in the difference between SSMI and AMSR-E satellite sensors (NSIDC uses SSMI, JAXA uses AMSR-E).
We also don’t see an adjustment at Cryosphere Today, and they also use SSMI:
Nor does NANSEN:
Click for larger images
If anyone knows why JAXA does the adjustment but the others do not, I’m all ears. My theory is that it is sensor related, but we should find out for sure. I’m swamped today, so I’ll leave this puzzle for WUWT readers to solve.
UPDATE
Dr. Walt Meir writes in with this:
Since you mentioned it on your blog, I can fill in at least some info:
You are correct. When the melt season kicks in the surface water changes
the contrast between ice and water. To more accurately measure the
area/extent, you should adjust coefficients to account for this.
This is done for SSM/I. However, because the SSM/I algorithm is
different from the AMSR-E algorithm (and other differences between the
sensors) the adjustment is different. In SSM/I, the adjustment is
smoother and thus there isn’t that “bump”.
You have to remember that AMSR-E is a research sensor and the algorithms
are still being refined. That is one reason we don’t use AMSR-E for the
long-term timeseries (though the more important reason is the
inconsistency between the two sensors and algorithms).
– Walt
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VG-Off topic, but you never answered my question about what book you were talking about by Garth Paltridge. What’s the title again?
What is the resolution on these satellite sensors? Is it feasible to set up earth-based standards to re-cal periodically with areas that are artificially kept at certain thicknesses of sea ice?
It would seem to me that if you could focus your sensing to an area the size of a football field or so, you could literally create a standard to cal from.
PaulK
this self-declared science blog
I think you’ll find the ‘Best Science blog’ award was the result of a vote by others.
IIRC, it was won last year by Climate Audit, which rather suggests that reasonable and courteous blogs are more popular than rants. Perhaps there is hope, after all.
Phil. (14:00:43),
Thank you for your prediction. Time will tell.
Apparently you wish to ignore the Northern Hemisphere sea ice graphic from the University of Bremen posted here by Shawn Whelan: click
And you don’t want to accept the So. Hemisphere sea ice chart: click
Finally, you never answer my repeatedly asked question: is it your belief that an increase in CO2 will cause runaway global warming and climate catastrophe? Because that’s really what all these posts are about. In fact, that’s what the entire AGW argument is all about.
Time to take a stand on the CO2 = runaway global warming question: Yes or No?
Skeptics say No — and so far, the planet agrees.
Thanks for the graph, very useful.
Let’s chill a little here. I go off to do some things and come back and see we are up to our knees in slush, ice, and water again. Maybe the so called troll can explain to me what all the fuss is about. There seems to be some disconnect about the fact that the part of the world near the North Pole, the Arctic, is an ocean. Most of the time some part of it has floating ice, some weeks it is completely covered with ice, and sometimes it has very little and perhaps none – ice free. If and when the latter happens I wonder how long it might last? A month? Six weeks? I’m curious. Anyway, Mr. Troll, as the comings and goings of the Arctic Ice seems to be quite variable as we have learned from historical documents and more recent measurements I’m still betting on fire to destroy Earth but as R. Frost knew either will do.
John
Some say the world will end in fire,
Some say in ice.
From what I’ve tasted of desire
I hold with those who favor fire.
But if it had to perish twice,
I think I know enough of hate
To say that for destruction ice
Is also great
And would suffice.
— Robert Frost
davidsnelgrove, norfolk England (12:09:24) :
“. . .the UK Hadley centre predicts that by 2080, London will be experiencing temps of 120 degrees F.,”
Say what? Good luck on that.
Someone should tell them London is on a large island surrounded by seas. The vertical sun recently passed over Kingston, Jamaica so one might expect great solar input there the past week. The high temperatures this week are expected to be in the mid-to-high 80s.
A previous post by Jeff Id shows why some of the sea ice measurements claiming a huge ice loss are unreliable: click
Here is one [cherry-picked] graph from the link above: click
The argument over sea ice extent is similar to the argument over ocean acidification, coral bleaching, etc.: they are peripheral questions. The central question is, as always: will an increase in CO2 cause runaway global warming and climate catastrophe?
The CO2=catastrophic AGW question can be answered three ways: Yes, No, or Maybe.
If Yes, then the discussion should be about cost/benefit analysis. How many degrees of temperature mitigation [if any] can we expect per trillion dollars expended? And perhaps more importantly: will the entire world community do its part in mitigating the problem? If China continues building two new coal-fired power plants per week, as they are currently doing, should the U.S. and the West shoulder the entire burden? China is becoming rich fast, and can no longer fall back on the argument that they get to continue pouring unrestricted emissions into the atmosphere in order to catch up.
If No, then no more public funds should be spent on studies of
AGW; private universities are perfectly capable of monitoring the situation without rent-seeking tax hounds suckling at the public teat. NASA currently spends over $5 billion a year for various “global warming” studies. If CO2 does not lead to runaway global warming, these $billions should be spent on problems that science can solve, such as sanitation, fighting malaria, immunizing children against disease, etc.
And if the answer is Maybe, then the question is undecided because evidence of AGW caused climate catastrophe is lacking. If the answer is Maybe, then there should be a series of very public debates conducted in neutral venues by credible scientists on both sides of the issue.
The undeniable fact that the AGW side avoids public debates shows that they lack the arguments necessary to justify their feeding frenzy at the public trough.
Jim (12:24:36) :
Aron, I don’t see any numbers in the reindeer article. Of course, there is also no methodology – the downfall of many Global Warming Wizards of Oz!!
Yep, it’s a real worry. Due to global warming, the reindeer/caribou herds have dwindled down to only about 3 million.
The lower count is probably due to the herds moving around year to year and fooling the census takers, and maybe a little bit due to the increase in wolf populations, which I think is a man-made situation.
.
Dave (13:16:06) : makes a point – we have only 30 years of ice measurements. Everything prior is just guesses from ground level or narrow aircraft flight paths. We have photos of North Pole submarine surfacings in open water in ’59, ’62, and ’87, Amundsen’s northwest passage in 1905, and a couple Canadian passages in the 1940’s. Arctic ice must have been down then, so the late sparsity isn’t unique, especially given that much of it is driven by Siberian winds pushing ice into the transpolar drift and out into the Atlantic.
So much of what constitutes debate between ‘warmists’ and ‘deniers’ comes down to repeated rounds of tug-of-war. ‘My data is bigger and better than yours’
This is tiresome. Forget the numbers for a moment, let us narrow the scope of the argument to that of Arctic Ice coverage and think about this.
If ice extent is diminished, to such a level, that the North West (NW) passage becomes navigable would this be as unprecedented and catastrophic to Man, Ursus yellow-fur and caribou as some claim?
If historical records show that the NW passage has been unbreached then I’d be worried. Aliter, I’d be severely relaxed.
Anyone know?
Henry Larsen travelled from Halifax to Vancouver in 86 days in 1944 through the Northern route of the NW Passage. Likely impossible this year.
Which means after 60 plus years of AGW there is more ice in the Arctic now than in 1944.
http://www.ucalgary.ca/arcticexpedition/larsenexpeditions
Shawn Whelan (16:11:44) :
Henry Larsen travelled from Halifax to Vancouver in 86 days in 1944 through the Northern route of the NW Passage. Likely impossible this year.
Which means after 60 plus years of AGW there is more ice in the Arctic now than in 1944
Thank you Shawn – that’s an inference that can only be countered by over-indulgent, brain-waxed climate-realist-refuseniks!
I’m not vindictive by nature but, sometimes, moments arise when one just has to be brutal to the smurfist-squad when their self-aggrandizing, dogmatism threatens future generations!
Shawn Whelan (16:11:44) :
Which means after 60 plus years of AGW there is more ice in the Arctic now than in 1944.
http://www.ucalgary.ca/arcticexpedition/larsenexpeditions
I was with you for a moment there Shawn but then I read your link. How can you claim that this is evidence that the Arctic had less ice in 1944 than at present. Name one peer-reviewed climatologist mentioned in the link. Show me the IPPC executive summary that backs up your claim – for goodness sake Shawn, you’ll be claiming next that photographic evidence exists showing US submarines at the poles in the fifties! You clearly have no understanding of how many Principal Components are needed to change History!
Nice one mate:)
RoyFOMR (16:29:24) :
Not to mention that Amundsun SAILED the NW passage in either 1903 or 05.
DaveE.
Same sensor, different source, no speed bump.
http://i599.photobucket.com/albums/tt74/MartinGAtkins/Hamburg.jpg
paulK (12:19:37) :
AndyW35, I am certainly interested why this self-declared science blog, is so silent on the fast ice extent melt-off from late April until today. [Blah, blah, blah,…]
I get so tired of comments like this from both sides of the debate. When the Arctic sea ice extent approaches the 2007 level, the alarmists dance a jig; when it approaches the 1979-2000 average, the skeptics do a song and dance. These short term trends have little to do with global warming and much to do with atmospheric circulation patterns. NASA says so. The NSIDC says so. You can see it with your own eyes in the animations Anthony has posted here. This is what the otherwise alarmist NSIDC says at the end of their 6/3/09 report:
“Whether or not Arctic sea ice reaches a new record low this summer will depend on the circulation patterns that set up over the next few months.”
Cryosphere looks to have updated today.
The areas that seem to be contributing to the quick decline are on the Atlantic side. The Barents, Greenland, and Baffin/Newfoundland seem to be where the negative anomalies are greatest. And the Chuckchi on the Pacific side. The main basin areas and Hudson seem to be holding there own much better this year. The Beaufort doesn’t seem to be losing ice nearly as fast this year, as compared to the last couple years.
So its not the overall loss, but where we are losing it. Weather ,and currents a bit different this year, I suppose.
Oh RoyFOMR, you have sold yourself.
Since a NW passage wasn’t possible in 2007 but was in 1944 prior to 60 years of CO2 induced warming then Shawn is stating fact. Your knee-jerk ad hominem shows your inability to fit your faith to the science.
Incidentally as more and more ridicule is poured on alarmists like yourself, primarily by the weather itself 😀 , have you given any thought to how your children will laugh at you?
Reply: Tone it down everyone. And as always, I don’t care who started it. ~ charles the moderator
The University of Hamburg chart still has a speed bump, it is just a little smaller and implemented a little earlier than Jaxa’s.
For those interested, this is what the NH sea ice extent looks like compared to all the years since 1979 (with 2009 and the two highest and two lowest years highlighted).
http://img199.imageshack.us/img199/9079/dailyseijune10.png
Mike Abbott (16:58:39) :
Like you, I get tired of the ping-pong numbers game. To reduce a complex spread of alternatives into a singular metric and then base an entire future upon its magnitude and sign, reeks of an hubristic and fundamentalist, Talibanisation of Science that behoves us badly.
Has it happened before, will it happen again and, if it does, what should we do is a darned sight more pragmatic and useful than any amount of ego-driven pontifications – however backed up by pretensious preeners!
Sandy (17:23:20) :
Didn’t you notice that my tongue was heavily within my cheek while me fingers and toes were crossed? I’m 100% on the same side as you, mate. Some call it irony but in my case it’s just a wicked SOH!
Reply: I didn’t want to explain it to him ~ charles the moderator
Sandy (17:23:20) :
Get your sarcasm detector recalibrated 😉
DaveE.
“I didn’t want to explain it to him” or her.
RoyFOMR (17:30:44) :
Mike Abbott (16:58:39) :
Like you, I get tired of the ping-pong numbers game. To reduce a complex spread of alternatives into a singular metric and then base an entire future upon its magnitude and sign, reeks of an hubristic and fundamentalist, Talibanisation of Science that behoves us badly.
Furthermore, whenever a “new record” for Arctic sea ice extent is mentioned, it is usually not noted that an official record only exists for the last 31 years – a blip in time. And that official record begins in (I believe) 1979, which was in the middle of an extremely cold period in the northern hemisphere. Weren’t we being warned about “global cooling” then? It’s a coincidence that that is when accurate satellite data became available, but the alarmists couldn’t have cherry-picked a better starting point…
Ok Sandy, you’re on the first round, I’m next and, if Gavin S or JH comes in- then we’ll find another place to sort the world out.
🙂 – Cheers, Charles-Not only will sandy and I feed you the amber beverages we’ll even club together to ensure that you get home safely. WhatzUpWieVat?