Back on April 2nd, it looked like Arctic Sea ice extent at NSIDC would cross the “normal” line. See: Arctic Sea Ice Extent Update: still growing
The image then looked like this:
Now before anyone starts trotting out claims of “adjustments”, I’ll point out that the independent JAXA data set, done with a different satellite and the AMSR-E sensor shows the same thing:
Note the area I’ve highlighted inside the box. Here is that area magnified below:
The NSIDC presentation is zoomed to show the current period of interest, whereas the JAXA presentation shows the entire annual cycle. So we notice small changes in NSIDC more often. Also, the NSIDC presentation is a running 5 day average according to Dr. Walt Meier.
Of course whether you are scientist, scholar, layman, casual observer, or zealot, nature never gives a care as to what we might expect it to do.
So worry not, no skullduggery is afoot. Nature is just laughing at all of us.
Steve Goddard said:
It will almost certainly cross the NSIDC median line over the next few days, because the Newfoundland median line is pulling back quickly this time of year, and because of very cold air over the Bering Sea and Sea of Okhotsk.
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Pretty strong words…”almost certainly”. But it could happen I suppose. But how long will it stay, and what will the ice look like in September? Both far more important longer term events I would say…
A great deal of March’s “bump” award has been in the Bering Sea, where persistant low pressure has cold air across the current ice pack and created new ice, (very thin new ice, 4 to 12 in. thick) on the SW side of the Bering Sea ice pack. The sea of Okhotsk is running about normal, and the Atlantic side, New Foundland etc. and Hudson Bay, running below normal. Watch for rapid melt in these areas, and also in the Greenland sea area and over to Siberia.
I see no conspiracy there. THe sudden change matches the late turning of the season from extra-cold to normal in my distant North Carolina perspective.
Stuff like that just happens.
The key here is that if different observation platforms come up with the same information, and those observations can be relied upon with a high level of confidence, that those results be reported as observations.
This is what Anthony has done.
This is what the AGW hypothesis crowd, The Team in particular, would not do.
The integrity contrast is not only of interest, but integral for making progress on the questions about climate change.
R. Gates
Actually the number should be more negative regardless of AGWT since there is another theory… One that involves natural cycles.
Now, it may well be that we are entering a new downturn in temperature over the next decade or so, however temperatures have been warmer at times in the last several thousand years so I would expect in general we are still coming out of the last big cold spell we had ( the little ice age ) where temperatures dropped significantly from the MWP ( Medieval Warm Period )
These temperatures have been steadily growing and I bet if you were to look at the warming rationally you would notice no exponential growth in the warming ( as seems to be shown in most models ) However there is warming. Now some of that warming may be attributed to shoddy work in trying to compensate for UHI,
Regardless while AGWT does explain a reduction in ice, so do any number of other competing theories. Do not latch onto only one explanation. It may well be that CO2 is the primary cause of the warming. It may also not be.
Now if the trend continues up does that discount AGWT??? To be honest what the people who believe in it will do is say, “oops, we made a miscalculation… It is still occurring but the melt will not be one of the side effects until such and such a date”
So even IF the chart does not go negative an explanation will arise to keep the theory alive.
Again I am not saying AGWT is wrong, but it is simply a theory and people revise theories all the time as new evidence forces them to analyze the theory. Please just consider that AGWT is not the only ‘theory’ as to what is occurring.
personally, I am not at all concerned with the way arctic ice extent is going : the JAXA chart shows it right at the top for this time of year (since 2003). like many others here, I will be watching to see how low it goes in september ; unlike mr. Gates, I don’t think it will go as low as 4.5 million sq. km. I see it being somewhere between 5 and 6 million sq. km. but what I will also be watching for, with great interest, is to see where the 2010 line (JAXA) goes in may and november. if like 2009, it goes to the top in may and the bottom in november, indicating a slower decline in the spring and a slower increase in the fall, this will support Svenmark’s theory about cosmic rays and cloud formation. this looks to be a very interesting year.
R. Gates (09:57:13) :
But alas, global sea ice extent continues below normal (due to the current refusal of arctic sea ice to cross that invisible barrier no doubt).
Normal in this context, sometimes it’s above and sometimes it’s below? Or does normal mean something else here?
Sea ice extent and area is closely monitored for navigation purposes and the last thing you want to do is adjust/homogenize/sanitize/treering it for one of those ships starting out to sea. Lives are at stake, business dollars are at stake, and expensive ships are at stake, not grant dollars. Because of these cross-check entities, I don’t think we have much to worry about regarding “single adjusted data set” issues.
In Spring the ice stops growing and the grass starts growing…
In Autumn the ice starts growing and the grass stops growing…
They’re almost a mirror of each other… Twas ever thus… When that changes – WORRY!
Yes, I’ve been following Arctic ice for a few months. It’s definitely interesting.
In similar years of winter/spring weather patterns, ice growth within each Arctic zone, and ice flow, summer flush was less than in other years under flush conducive parameters. This year stacks up with lower ice flush and melt for the summer. R Gates, what is your opinion about statistical models of ice flush?
When i look at the animation where the blue line appears to be touching the long term average and in the next phase of the animation seems to back away from it i have the feeling that this “backing off” seems to be about 1 pixel,
so the visual effect could just be an effect of rounding off a scaled measurement value to a screen coordinate.
You really can’t make out such fine details from such a screen grafic, it has a coarse reolution. It would help to have an interactive zoomable grafics widget. It would also be useful to have the real measurement points marked as dots to differentiate from the linear interpolation by the line drawing algorithm.
Steve Goddard said:
“Arctic, Antarctic and global will likely be all positive in a few days. Interesting death spiral…”
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Now Steve, really. If you know anything, you know that a spiral means subject to natural variability (like this winter’s extreme negative AO). On a longer term basis (longer than one winter), Global Sea ice has spent more time since 2004 in the negative anomaly range than the positve, and this longer term perspective is all that matters. In a “death spiral” you’d expect it to recover, pludge, recover, pludge, with each pludge (over a period of decades) to be lower, and each recovery to be not quite as great, when looked at from a long term perspective.
This months “re-growth” of the arctic sea ice to almost normal (which is nearly all in the Bering sea in March’s bump upward) is certainly related to the negative AO index.
An honest scientist wlll look at the longest trend of reliable data, and so March’s little bump upward, while interesting as an effect of the negative AO index of one winter, means very little to me unless it persists in the longer term…
What does the acronym “AGWT” mean?
What ? There’s earthworms tunneling in the rotten ice ?
R. Gates (10:29:54) :
OK I get it now. Arctic ice is almost all gone, and is also above normal.
REPLY: Note the label in the graph: “The latest date in 2010 is 03/30”. Once they get it updated I think it will look much like NSIDC. – Anthony
Smokey (10:31:28) :
What does the acronym “AGWT” mean?
REPLY: I believe it is for “Anthropogenic Global Warming Theory.”
As far as I’m concerned, theory it remains. The science remains far from settled from all appearances.
AGW proponents would really benefit from toning down the hysteria…vast segments of the world’s population (lately, the Germans!) are checking out on the “commonly held beliefs” including permanent ice-free polar regions, melting glaciers etc.
Also, keep an eye on Mr. Sun (Ms. Sun?) as it appears to be slipping back into a comfortable minimum state once again:
http://www.spaceweather.com/images2010/04apr10/midi512_blank.gif?PHPSESSID=bskm9n0gojo6prs85ivcmrlmf3
Nansen (Arctic-ROOS) is back online, their curve still goes up, but they have not reached April yet.
Anthony & Pamela Gray (09:38:42) :
What do you mean they are not trying to hide anything, the values from the previous days have been adjusted down. Do they do that on their own then?
Or are you saying they made mistake which they have now corrected?
R. Gates – pludge ? I am unable to find this word in either the oxford or webster’s dictionary ; surely you mean plunge.
R. Gates (10:10:22) :
I make predictions for a few days, weeks or months. If I am wrong, you can call me on it in the near future.
Some climate people make their predictions for 100 years out, knowing that they can inflate their numbers to whatever value they want, and never be held responsible.
http://www.physics.utoronto.ca/news_repository/will-oceans-surge-59-centimetres-this-century-or-25-metres
A C Osborn (10:47:38) :
Ice extent varies a lot from day to day because of wind and the way that extent is calculated. Ice area is less volatile and is above normal.
http://arctic-roos.org/observations/satellite-data/sea-ice/observation_images/ssmi1_ice_area.png
Smokey’s right.
http://arctic-roos.org/observations/satellite-data/sea-ice/ice-area-and-extent-in-arctic
Importantly they say we are above the 1979-2006 average.
Anthony this happened everytime ice went up before and the changes are documented at this site.
http://mikelm.blogspot.com/2007/09/left-image-was-downloaded-from.html
However, in this case I suspect no fowl play as the ice is in fact staying “normal: and follows DMI closely. It is precisely because people have taken notice of past changes that these sites may be quite careful about what they are doing these days with the graphs re adjustments etc…
Check back in about thirty years, when the priests … I mean scientists … after studying the entrails … I mean data … discover that there’s been a nice upward trend in sea ice extent and will require more funding to figure out what’s been happening and, after another couple decades, will discover that the ice extent is cyclical in nature.