« Through the eyes of Healy | Main | September SEARCH Outlook Contribution »

Comments

Feed You can follow this conversation by subscribing to the comment feed for this post.

www.google.com/accounts/o8/id?id=AItOawkpUaD_uYjZAIrhpA6AA5KyEs-CSoL4zlM

Neven

I used one of my old links instead of the new one before i posted the last post...

And NSIDC ist online again now :-)


Arctic sea ice near record lows
Arctic sea ice extent averaged for August 2011 reached the second lowest level for the month in the 1979 to 2011 satellite record. Both the Northwest Passage and the Northern Sea route appear to be open. Throughout August, sea ice extent tracked near the record lows of 2007, underscoring the continued decline in Arctic ice cover.
...

more on http://nsidc.org/arcticseaicenews/

Chris K

Neven

Thanks again, Chris. Post is up.

Patrice Monroe Pustavrh

Nice post, Neven. Well, there is one thing that bothers me, anyway. Would it be for the first time in history to sail around Severnaya Zemlya islands in history, or not ? Cause even in 2007, Laptev sea area was not so clear of ice. I know, it might be just weather, but... More and more open northern passages just responds to big picture of what is happening in the north. Maybe, sailing around SZ will be just another challenge to Borge Ousland ;)

Christoffer Ladstein

Twemoran, thanks, I've heard of those but will soon refresh my memory, sound as scary as those winds that is pushed in front of great snowlavines, takes place Every winter along the deep (winterdark!), fjords and valleys at the western part of Norway!? Everything is blown to pices, that's for sure...

Thanks Neven for noticing the AWFUL weather we're witnessing in Norway these days (and almost the whole summer!), my kids felt more than pleased when I took them for their excercises by CAR, not bike, today. The place not getting wet in this weather (the remains of Irene BTW), is not worth mentioning. Result: Almost all grain-production will go for the pigs, and all grain for us humans must be imported, no problem for little rich Norway, but I'm getting worried for the foodsituation globally, due to more extreme weather episodes. On the other hand, EU & Eastern Europe got a LOT of potential for doubling todays production...

Not any BIG changes in the extent for tomorrow, we might hope for -35K?!
And due to all that thin and less concentrated ice, I also am a strong believer in a 10 day decrease of roughly 35K a day...

r w Langford

Piteraq weather coming to Tasiilaq in Eastern Greenland http://vimeo.com/1763066 and a much different summer day at same site. http://en.wikipedia.org/wiki/File:Tasiilaq_-_Greenland_summer_2009.jpg

Twemoran

I drove across the Canadian West in May and June of this year - and everything was under water.
Don't expect Canada to be exporting wheat this year.

Kevin McKinney

35K? The fat lady LAUGHS at 35K.

Extent for September 6: 4,576,094 km2.

If it holds up (and my memory and tequila-inhibited mental arithmetic, too) that's 41K, give or take.

Paul Klemencic

I expected a bigger IJIS loss.

I did a blink comparison of today's final Bremen map versus the one for September 4 ( covering the 48-hour data collection period), and there was massive ice edge pullback in all regions, although the Laptev Bite was pinched.

Given the sequence of the last three days of IJIS reports, it appeared today was going to be a very big loss, especially after Bremen showed a very big loss yesterday.

L. Hamilton

Historical record for the PIOMAS estimates. I updated the year-to-date graph here (also on our graphs page),
http://img.photobucket.com/albums/v224/Chiloe/Climate/sea_ice_VOL_min_to_date.png

IJIS graph with tonight's prelim:
http://img.photobucket.com/albums/v224/Chiloe/Climate/sea_ice_JAXA_min_to_date.png

Chris Biscan

http://www.americanwx.com/bb/index.php?app=ccs&module=pages&section=pages&folder=/models&id=6


http://www.iup.uni-bremen.de:8084/amsr/ice_ext_n.png


Bremen PLUMMETS AGIAN, FLAT OUT PLUMMETS.

what the hell is going in with Jaxa?

Guess 12.5km grids are that much different. Maybe Jaxa will catch up today.

either way the euro torches the arctic also has a sick compaction regime....just brutal.

it would not only set records Bremen, NSIDCm and Jaxa would all be under 4,000,000km2.


stay tuned.

Nick Barnes

That ice is fast ice: sea ice attached to the shore. Not an ice shelf. Please don't call it an ice shelf. An ice shelf (like the Ward Hunt ice shelf, for instance) is a different animal.
I'm not aware of a study showing the age of this particular fast ice. Does anyone have a cite?

Neven

As Chris mentioned in the latest PIOMAS thread, the ECMWF forecast shows things for next week, that if they come about, we are in for a grand finale to the melting season.

Luckily there are a few more days left until Saturday, so we can see how things develop from here. But again, if this comes about, what I have written in this SIE update becomes totally irrelevant. Thin ice, warm waters AND perfect weather conditions... Oh, dear.

Let's wait and see.

Chris Biscan

Everyone watch out for the Fram to get flushed out and a large hole around NE Greenland to come about by 48 hours from now.

Also winds compacting the laptev pick up right now.

the next 36 hours 200 miles wide of 15-25kt winds will pummel the laptev.

we can already see on early modis images that ice there is receding.


the fram gets insane winds. 3 days of 20-35kt winds sustained with 25-33kt for most of it almost all the way to the NE tip of Greenland.

we might lose 100,000k there in the next 2-3 days.

the main pack is cut off till day 3 so it will create quite the hole.

these winds are howling.

I will post updated wind chart in 20 min for the morning crew to look at in awe.

amazng stuff.

just wait.

Neven

Chris isn't exaggerating:

Peter Ellis

Chris B and Paul K: PLEASE STOP NAIVELY COMPARING THE IJIS GRAPH TO THE BREMEN MAP DATA.

I don't know how to say it more clearly. They use different algorithms to estimate ice concentration. They are not simply comparable, over and above the resolution difference.

The visual map representation for the IJIS ice concentration data is here:
http://www.ijis.iarc.uaf.edu/cgi-bin/seaice-monitor.cgi?lang=e

If you compare that to the IJIS graph, you'll see a much closer correspondance between the map changes and the numerical extent changes.

Compare the Bremen map to the Bremen graph, and the IJIS map to the IJIS graph. Please. For all our sakes. Anything else is just reading bloody tealeaves.

The only time you should be cross-comparing these is if you want to do a serious study into how the different algorithms perform at detecting sea ice: and in that case it would make much more sense to compare one map to the other map, and just leave the numerical graph out of it.

Chris Biscan

now:

http://i174.photobucket.com/albums/w109/frivolousz21/0600gfs.gif

12 hr:

http://i174.photobucket.com/albums/w109/frivolousz21/0612gfs.gif

24:

http://i174.photobucket.com/albums/w109/frivolousz21/0624gfs.gif

36 hr:

http://i174.photobucket.com/albums/w109/frivolousz21/0636gfs.gif

48 hr:

http://i174.photobucket.com/albums/w109/frivolousz21/0648gfs.gif

WOWzers

60 hr:

http://i174.photobucket.com/albums/w109/frivolousz21/110907102011.gif


After that the Fram gets a break but still has 10kt winds flushing out.

by day 3 the winds in the ESB/Chukchi are pushing 25-30kts inward towards the central arctic.

this slowly expands from days 4-9 on the euro bringing in very warm air.


Neven

Larry, I've promoted your graphs to the top of the Daily Graphs page.

I've also put the Arctic.io ice drift vector map in there. Check out those arrows in the Greenland Sea from day 2 to 6.

Seke Rob

Neven, the top right DG chart now appears twice, after a Ctrl-F5.

cheers

Neven

Seke Rob, I know. I didn't know what to replace that area graph with, so I just let it stand for now.

Philiponfire

Neven your 12.24 talks about a drift vector map but the arrows link goes to today's modis picture was that your intention?

Neven

Sorry, Philiponfire, I should have been more specific. I wrote a post yesterday that explains how it works and how you can use Overlays to see the ice drift arrows.

Chris Biscan

Jaxa had a 11.5k upwards revision.

now 4,587,855km2


Crazy to see all these major revisions upward with the single days even from Norsex, Bremen, NSIDC drop so fast.

Peter Ellis

Crazy to see all these major revisions upward...

No. Really, no. The Jaxa revision is almost always upwards, and this particular one is nothing out of the ordinary. The Bremen map is irrelevant, because the Jaxa number is (as I said above) based on the Jaxa map.

You have no basis to say "single days even from Norsex, Bremen, NSIDC drop so fast" because you do not have any single-day data from Norsex or NSIDC, and the only single-day data you have from Bremen is your own subjective impression of their map, not a numerical value.

Bremen and Jaxa are two near-independent data sources: no more, no less. Arguing that either of them is "crazy" is at best misguided and at worst makes you sound like a crank.

While we're at it, can we please have less of the "plummeting", "torching" and "awe" when talking about the Bremen map. Total extent is just lower than 2007 according to Bremen, and the rate of loss is slightly elevated for the time of year. However, it is not plummeting. The rate of loss is slowing as we reach the end of the season, as can be trivially seen by eyeballing the graph, or calculating the average over a few days. There are random noise wiggles around the (approximate) sine wave pattern.

Bremen is noticeably more noisy than other extent graphs, presumably due to the fact that it uses daily values. The algorithm they use may also be unstable/noisy in areas of low extent - as witness several "flash melt" claims from the maps that have mysteriously reappeared over the next couple of days. Picking on every little downward wiggle as an apocalyptic event is simple pareidolia,and it's getting annoying.

Put the microscope down, take a few deep breaths and a step backwards. Look at the wider picture, and stop hyper-focusing on the daily noise.

Christoffer Ladstein

"35K? The fat lady LAUGHS at 35K."

Well, Kevin, who's to laugh last now, ha, ha!

As Peter so clearly put it, it's hard to stay sober when looking to close at the "daily noise", but isn't that humanity in a nutshell?! We strive for longer plans, but even politicans fall short in making those plans come true.

The wind at todays weathermap do tell of compaction going on from the Laptev/East Siberian Sea direction the Pole, and combined with Chris B's "Fram-stuff", we have something to look forward to, don't we.

Congratulations to Larry (and Neven of course!) for being granted "Boss" of the Charts-page!

Neven

as witness several "flash melt" claims from the maps that have mysteriously reappeared over the next couple of days.

Hold on a minute. That was/is pretty interesting to look at and discuss. I did my utmost not to be alarmist in any way, but when you have a cyclone going through slush puppie ice and the blink comparison of the Uni Bremen SIC map shows what it did, I'm not going to sit back and say: 'Just a sensor, just an algorithm, just a little downward wiggle, nothing unusual'.

We want to know how weak the ice is compared to other years, right?

Total extent is just lower than 2007 according to Bremen, and the rate of loss is slightly elevated for the time of year. However, it is not plummeting.

I believe yesterday Larry informed us of the fact that Uni Bremen SIE had gone down 114K. I'm sorry, that's plummeting in my dictionary, especially around this time of the year.

Besides, "just lower than 2007" when weather conditions haven't been like 2007 at all for a substantial part of the season, is pretty spectacular IMO.

While we're at it, can we please have less of the "plummeting", "torching" and "awe" when talking about the Bremen map.

I see what you mean, but I don't think it's that disturbing. And not always exaggerated either. The major downside to me is that it wears off quickly.

Patrice Monroe Pustavrh

Interesting, CT Area is still below 2007 with new update at 2.974. Now, for 2007, Area dropped sharply tommorow and had another drop day after, but that is all what CT Area did in 2007. Let us see, how 2011 will do in next days to come.

Peter Ellis

Blah, typed in a long reply and my browser ate it. Here goes once more, apologies if anything shows up twice :-(

Neven, I apologise if I seemed to be targeting you in my last comment. Both your posts on flash melting have been interesting, and entirely appropriately argued in terms of "This sensor is doing something astonishing, what's going on?" The fact that in both cases you've then gone on to discuss how some of the ice seems to reappear, and possible causes of that, shows that you're approaching the data as a scientist.

I don't get that impression from all the contributors - every drop is taken as gospel, and data sources that disagree are labelled as crazy, or accused of carrying unannounced smoothing / processing of the figures. Every possible weather forecast is bad news - if the winds are divergent, well then the ice is being blown into warmer waters. If convergent, well then warmer winds will "torch" the ice. There is a lack of appropriate scepticism, and of equal respect for all data sources. (Note, HYCOM isn't data, it's a model, so we're still free to say their thickness estimates are miles off target ;-) )

Personally, I think there is an absolutely fascinating blog post waiting to be written comparing the Bremen map, the Jaxa map and the optical/infrared MODIS data. Looking at those together would allow us to begin to look at how the cloud cover (and/or "swamping" of ice by storms) affects each data source differently. If I only had more time, I'd offer to write it.

Neven

Neven, I apologise if I seemed to be targeting you in my last comment.

No problem. I like to go over the top every now and then myself, for example by coming up with silly labels like "Slush Puppie ice", "flash melting" or "Laptev Bite". Or last year's "North Hole". :-B

I don't get that impression from all the contributors

Don't forget that they are also bringing things to the table that nobody else has been bringing so far, such as day-to-day interpretations of weather forecasts and sea ice concentration maps, which I personally find very stimulating (because it helps me to think about stuff I want to put into the weekly SIE updates).

And although they could tone it down a bit in some ways, it's not at all crazy what they're saying. Remember, you also jumped on Paolo when he speculated that the ice had broken up in front of Barrow, which three days later turned out to be correct.

So, just wait till the end of the season. When I look around here, I only see very reasonable people. In this sense there is nothing to worry about.

If I only had more time, I'd offer to write it.

Yup, that's too bad. I couldn't write such a blog post, even if I had the time. :-)

You are very welcome to write a guest blog post whenever you feel so inclined and/or inspired.

Paul Klemencic

Peter Ellis, I think you need to take a deep breathe yourself, and take a good look at L. Hamilton graphs on the Daily Graphs site. Also read the NSIDC latest report, where they point to Bremen data as being potentially more accurate. When the professionals point to the ice extent product they look to, you should listen.

The last several days showed big losses of extents on all the maps, and now the Bremen data show current ice extent within 100k sq km of breaking the 2007 low. If I choose to follow this measure, especially since the NSIDC pointed to it, then I am free to do so. And I will continue to base my comments here on the bulk of the ice extent measurement tools (maps, reports, graphs, news reports etc) and not limit myself to only the IJIS numbers.

I now believe that the chance of breaking the 2007 extent low is almost certain, since the best measure of current extent is within 100k of that low, there is a lot of vulnerable ice in several regions, and the weather is conducive for further loss. I am allowed to say that here, in spite of your protestations.

Chris is an enthusiastic young man (compared to an older beaten down guy like me), and give him a bit of slack to exercise his enthusiasm... everyone here can probably discount any exaggerations.

But in the end, if my analysis in the first paragraph holds up, Chris and a few like him, will have been more on the mark regarding the final minimum than many others relying on hard data extrapolations. Sooner or later, with such a vulnerable pack, the right weather conditions were likely to hit, although none of us expected that the right weather would hit in almost the last week of the melt season.

Chris Biscan

Peter,

we have gotten multiple single day reference for NSIDC on other blogs.

I can also take a map and plug it into photoshop or ecxcell and use a ruler that goes to 1/64 or 1/128 of an inch with the values of the graph and the bottom of the pixel line to see daily drops.

You mock me and others here.

Yet all of the data, ALL OF IT. shows the ice pack being on it's last legs.

I guess we should pretend it's not happening so we can be skeptical of it or something.

The floor is all yours, you present the skeptical arguments with new data we don't have. Because all of the available data from reliable sources tells us what is going on, including hundreds of humans currently in the arctic doing work.

I also know how to read a Skew-T, interpret any model weather chart that I know off. I have a feeling my descriptions of the forecasts are pretty accurate. If you haven't noticed. Bremen the one not plummeting is -60,000k from breaking there all time low in 2007 with possibly 2+ weeks left to go in the "melting season".

NSIDC is at 4,450,000km2 on September 6th. What were they every year except 2007, 08, and 10 on September 6th?

CT is under 3,000,000km2 again with 2+ weeks to go in possibly dropping another 100-200K.

Jaxa is a 4,587,000km2 on September 6th.

2010: +506,000K
2009: +728,938K
2008: +300,000K
2007: -140,000K
2006: +1,331,438M
2005: +1,100,000M
2004: +1,300,000M
2003: +1,540,000M
2002: +1,100,000M

We are 3.5 or so milion lower then any year in the 70s.

We are 2.5 million or so lower then any year in the 80s.

We are 1.5 to 2.2 million or so lower then any year in the 90s.


I look forward to your skeptical data.

Thanks in Advance.

Chris Biscan

Thanks Paul.

I am just here to learn and have fun.

I probably come off a bit crass and arrogent sometimes. But I have to back my ideas and work on this some how through a text box, it doesn't always work.

I know I use to strong of adjectives sometimes.

But we are also seeing some radical changes in the ice pack that are real. I can't help that they are real.

I Wish it wasn't so.

Lucia (The Blackboard)

Paul
I now believe that the chance of breaking the 2007 extent low is almost certain, since ....
Do you mean you think the chance of JAXA specifically reporting a record low is virtually certain? Or do you mean the chance of at least one of (JAXA, NSIDC, Bremmen etc.) reporting a record low being almost certain? Or something else?

Ned Ward

I've cajoled a friend of mine into calculating 15% extent numbers from the archived Bremen maps available on their website.

There are several different versions of the maps. I believe he used the ones generated by the ASI algorithm in the "180" map grid. (See the README file on the Bremen archive if you don't know what this means).

I don't know whether these are the same product that is used to produce the regular daily graph. The numbers do seem to be a bit different from what Larry has posted. Also, obviously, don't rely too heavily on this -- you're looking at numbers generated by some unknown guy on the web, fer chrissakes. If you want something official, call up UB and ask them.

Here is a graph comparing the extent data from MASIE, IJIS, and Bremen from 1 August 2011 through today (well, through 2 Sept. for MASIE, which hasn't updated lately).

I then calculated each day's average of IJIS and Bremen (I would have included MASIE, but there are some days missing). I fit a quadratic model to this average, to represent the smoothed general trend in extent over this period. This graph shows the difference between each data set (MASIE, IJIS, Bremen) and the quadratic trend.

Some notes:

(1) MASIE has been reporting the highest extents, Bremen the lowest, and IJIS in between.

(2) However, as we approach the minimum, the differences between the data sets are decreasing. MASIE and IJIS extents are dropping more rapidly than Bremen.

(3) The Bremen data have more day-to-day noise than IJIS, which would make sense if Bremen's numbers are based on 24 hours worth of imagery while IJIS's are based on 48 hours.

(4) I've seen Paul's argument that the IJIS data for day X should be compared to the Bremen data for day X-1 (or was it X+1?) but for now I'm just using the date stamps assigned by the data providers.

Ned Ward

For those who are interested, here are the numbers we (well, my colleague) generated by analysis of the Bremen maps in the archive:

Date Extent
8/1/2011 5983203.125
8/2/2011 6017656.25
8/3/2011 5909804.688
8/4/2011 5846054.688
8/5/2011 5733554.688
8/6/2011 5630703.125
8/7/2011 5638750
8/8/2011 5473242.188
8/9/2011 5415000
8/10/2011 5372421.875
8/11/2011 5303945.313
8/12/2011 5295937.5
8/13/2011 5209101.563
8/14/2011 5142617.188
8/15/2011 5049570.313
8/16/2011 5042421.875
8/17/2011 5010625
8/18/2011 5004765.625
8/19/2011 5015078.125
8/20/2011 4962773.438
8/21/2011 4894023.438
8/22/2011 4737421.875
8/23/2011 4750156.25
8/24/2011 4686875
8/25/2011 4592500
8/26/2011 4601914.063
8/27/2011 4629570.313
8/28/2011 4604492.188
8/29/2011 4515625
8/30/2011 4502656.25
8/31/2011 4391601.563
9/1/2011 4453320.313
9/2/2011 4512773.438
9/3/2011 4449921.875
9/4/2011 4390859.375
9/5/2011 4297148.438
9/6/2011 4287890.625

Again, these are a bit different from what Larry has posted. They were produced by reading in the maps, and adding up the area of all grid cells with ice concentrations of at least 15%. Please remember the disclaimer that these are not official approved Bremen data.

Also, FWIW, I think Peter Ellis makes some very good points above.

Paul Klemencic

Lucia, there is only one planet Earth. Not a IJIS earth, or an NSIDC earth, or a Bremen earth. On our planet Earth, I am saying that the ice extent is now almost certain to break below the 2007 levels.

By the way, the proper name for the product is IJIS, with JAXA (the Japanese equivalent to NASA) being one of the partners in the "joint" (hence the "J" in IJIS) effort.

After the bottom melt season ends, and compaction is the last remaining mechanism to reduce ice pack extent, the remaining ice should consolidate, and even in places begin to freeze together again. At that point the over-measurement problem using a grid four time larger in area will diminish, and IJIS extent should converge toward the smaller grid product (Bremen). IJIS should also converge with the five day averaged product (NSIDC), where the larger grid size inaccuracies are averaged out better than the IJIS product.

In the end, the current difference between Bremen and IJIS (about 230k currently) will likely close, with most of the gap made up due to IJIS declines. I expect that at the minimum, the gap shouldn't be more than 100k. The Bremen reported is likely to fall enough, that even the IJIS report will show a lower minimum extent than 2007. The Bremen, NSIDC five day average, and MASIE reports will almost certainly set new lows.

Espen

Peter,

This blog is not based on scientific work as U know, we are simply interested in what is happening in the Polar Sea, so the language spoken here is completely different to the boring "Scientific forums", and I love the atmosphere in here. We dont have to think about our "scientific career" or other vested interests, so please accept these facts!

Regars Espen

Ned Ward

Lucia, there is only one planet Earth. Not a IJIS earth, or an NSIDC earth, or a Bremen earth. On our planet Earth, I am saying that the ice extent is now almost certain to break below the 2007 levels.

OK, but how will you know if that happens?

Downil1

Peter Ellis/

This is after all a blog. One that follow a very slow event. Does it really matter if someone who has been waiting a year for the sea ice to reach it's minimum and
several years for the record to be broken gets exited when that's about to happen?

Had the texts here been parts of
scientific articles, words like "plummet" and "flash melt" would have been extreme. But that's not the case.

Perhaps the Bremen graph plummeted in comparison to what some of us had expected rather than in a scientific meaning.

crandles

Re "After the bottom melt season ends, and compaction is the last remaining mechanism to reduce ice pack extent, the remaining ice should consolidate"

Is this really compaction? I guess that while bottom melt continues small bits drop off. These small bits will melt out but while bottom melt continues they get replaced by other bits dropping off. As the bottom melt slows down, the rate at which bits fall off slows down and this is what makes the ice edge become sharper rather than winds suddenly becoming more compacting than dispersive.

Lucia (The Blackboard)

Paul--
I'm aware there is only one earth. I am also aware that our knowledge of the actual extent comes from measurements and to the extent that we know whether a record was broken, we need to look to recorded value.

I still don't know if you are actually predicting that the JAXA minimum will fall below the minimum recorded by JAXA in 2007. But I guess I can live without this knowledge.

Thanks for the tutorial on the 'proper' name for the product. I'm going to continue saying JAXA just as Gavin does in his post at RC. Feel free to visit RC and post a comment explaining the proper terminology to Gavin, including your explanation of the relationship between terms like "JAXA" and "NASA". Oh, and tell the JAXA folks to start typing IJIS instead of IARC-JAXA in the right hand corner of their graphs. Heaven forbid people their choice of labels might encourage people to use the word "JAXA" to describe their product.


Chris Biscan

http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png


According to my 1/64 inch ruler in Photoshop that is perfectly overlaid over the cross-hairs.

NSIDC is at 4,385,000km2(+/- 10,000km2)

Paul Klemencic

Ned, good question: "OK, but how will you know if that happens?"

Answer: When the preponderance of all the evidence point to that happening, and any remaining contradictory evidence has measurement uncertainties high enough such that the contradictory evidence can''t rule the new record low out.

I believe this is the usual answer to this question in science.

Paul Klemencic

Chris, the Bremen graphs generally lag a day after L. Hamilton updates his bar chart. Current Bremen measured extent must be less than 4.35 million to be reported at 4.3 million.

However, a note of caution is warranted, the more accurate measurement systems also show higher day to day variation. We could see some daily gains in extent, and the measured extent could bounce back up again.

But considering that we have a major LP system forecast to move into the Siberian side of the Arctic (as you and Neven have pointed out), this is likely moot. The weather points to continued loss of extent.

Paul Klemencic

Lucia wrote: " Oh, and tell the JAXA folks to start typing IJIS instead of IARC-JAXA in the right hand corner of their graphs."

IJIS is equivalent to IARC-JAXA; its the same entity.

And Gavin is a professional with working relationships with JAXA people who work on the IJIS product, as well as other products and reports. He can refer to them as JAXA, I have no problem; he knows what's going on, and who's who.

I was making the point that you know very little about the organization and product that produces the data you are using. Your inaccurate reply shows that, yet again. I think it helps to know something about the system producing the data. For other readers, I know this sounds like a broken record, but Lucia and others can't seem to accept this.

Bob Wallace

Perhaps the current localized heat wave would be improved by have a bit of Arctic chill blow through?

Jon Torrance

Paul,

It's okay for Gavin Schmidt to call the product JAXA sea ice extent but forbidden for Lucia? I think you're getting a little bit (actually, quite a bit) ridiculous now.

Lucia (The Blackboard)

Paul

IJIS is equivalent to IARC-JAXA; its the same entity.

Yes. Everyone knows this and were aware of it prior to your little lecture. That is why lots of people call the item that IARC-JAXA - same as IJIS labels with "IARC-JAXA" JAXA instead of calling it "IJIS".

He can refer to them as JAXA, I have no problem; he knows what's going on, and who's who.

I'm sure Gavin will be relieved to learn you have no problems with him calling JAXA JAXA.

Your inaccurate reply shows that, yet again.

What inaccurate reply? Gavin does call the data product JAXA. IJIS does lable the graph IARC-JAXA. You seem to have some gripe about me using the word JAXA. I'm going to continue to call it JAXA-- just as many others including Gavin do.

I think it helps to know something about the system producing the data. For other readers, I know this sounds like a broken record, but Lucia and others can't seem to accept this.
As far as I can tell noone has suggested it doesn't help to know something about the system producing the data. I haven't. I also haven't seen any of the zillions of people here discussing your various theories about the systems suggest that knowing something about the data product doesn't help. It seems to me I read a number of people suggesting that instead of fiddling trying to reverse engineer JAXA's algorithm, you just break down and read their description-- going so far as to provide you the link.

So, yes. I think it helps to know something about the data, as do many people here.

I most especially have no idea why you would think someone calling the product "JAXA" (as many including Gavin do) suggests they might not know something about the product.

Neven

OK, that's enough. We have more serious things to discuss.

Lucia, you know I love you, but I'm not having any wordy bickering from lukewarmers over here. I just ran into Tom Fuller on another blog and my tolerance levels have dropped as low as the Uni Bremen 2011 SIE trend line.

Paul, don't provoke Lucia.

Paul Klemencic

Neven, one of the reasons I am here, is that Tom Fuller posted my real name on Lucia's blog, using information from my confidential log-in that he had access to at his Examiner site. Lucia's moderators let the comment stand and didn't snip it.

Anthony Watts did the same thing to me at his site. First he sent me emails, then he snipped my comments on his site, revealing who I was (which he then deleted a week later), and posted comments on Roger Pielke Jr. site revealing my real name.

I couldn't continue to comment on their turf, using my real name. It was too dangerous.

You can snip this comment, if you wish. Just thought you might want to know about the kind of people you are dealing with.

Neven

Don't worry, Paul, Watts did the same to me and Fuller is obviously full of it.

I'm not asking you to spare Lucia (even though she's not so bad, just hangs around too much with the wrong crowd). I'm just saying we have more interesting/important stuff to discuss.

Lord Soth

You like IJIS and I like JAXA, You like tomato and I like tomahto
IJIS, JAXA, Tomato, tomahto, Let's call the whole thing off.


With appologies to Louis Armstrong and his descendants.


Peter Ellis

I will continue to base my comments here on the bulk of the ice extent measurement tools (maps, reports, graphs, news reports etc) and not limit myself to only the IJIS numbers.

I'm very glad to hear it, and I certainly don't mean to disparage the value of looking at area-by-area changes. The thing I object to is cross-comparing the IJIS numbers to the Bremen map (or vice versa) and using that to dismiss either source as "crazy", or claim some kind of methodological flaw in either team's work.

As far as the chance of a new record goes: I reckon it's about a 50:50 chance. I've said as much on various sites all summer (and in fact I believe I'm the only person dumb enough to have made an actual bet with Steven Goddard).

Chris B: I certainly agree that the ice pack is on its last legs - heck, I coined the "Great Arctic Comb-over" phrase - but I don't think this is the year. Next year or the year after, who knows? Maslowski said 2016 +/- 3 years, and I'd be willing to bet with anyone (alarmist or skeptic) on those terms. But for 2011 specifically, I don't think there's enough energy around to drive any kind of catastrophic collapse this late in the season.

My understanding is that bottom melt largely occurs around the fringes of the pack. We're now past the time of top-melt in the Arctic, so opening up of the central Arctic area seems very unlikely now: incremental melt of the slush in the Siberian sea will be the dominant story. The current average melt rates are of the order of 25k/day - well above average for the time of year of course, but it's only going to slow down further, not re-accelerate. As such, any daily loss of much greater than that value are almost certain to be noise / wiggles around the trend, and will be followed by days of near stasis. On a per-day basis you'll see everything from 50+ losses to slight increases - these will however average out. If we end up with a new record it'll be via the death of a thousand cuts and a late summer minimum.

Bob Wallace

My understanding is that bottom melt largely occurs around the fringes of the pack.

Is that because the ice tends to be thinner at the fringes or is there some other process operating?

I could see thinning at the fringes causing bits to drop off and float away to melt in a "larger bowl". The stuff inside the pack could be getting just as soft, but be contained.

Neven

I believe I'm the only person dumb enough to have made an actual bet with Steven Goddard

No way! Goddard was demanding insane betting conditions, although I wish now I had taken him up. How much did you bet? And on the IJIS daily minimum SIE, I presume?

If there is a God out there, you will win it!

Steve Bloom

Generally agreed about 2011, Peter, with the caveat that a big storm could do interesting things to all of that pancake ice in the central basin.

What were Goddard's terms, BTW? In any case I'm rooting for you too!

Peter Ellis

Bob: It's because open water outside the pack is warmed by the Sun, and then travels under the pack melting it from underneath. As it moves inward, it is cooled by the ice above it (it's melting the ice, so it's losing energy to the ice). By the time it gets more than a few kilometres into the pack, it's melted as much of the overlying ice as it's going to. Top melt, in contrast, occurs over the entire pack at once.

This, by the way, is why William Crump is wrong. He's making the (reasonable) point that first-year ice thickness in the central basin doesn't seem to be decreasing much each year, and the thickness changes we see in the central Arctic are due to changes in ice age distribution. By his logic therefore, even if the entire Arctic became first-year ice, it still wouldn't melt in the central basin. The flaw in the logic is that the bottom-melt zone is moving inexorably inwards year on year.

Neven: I was dumb and bet Goddard on his own territory - that there would / would not be an increase in MYI this year. My feeling then (as now) is that while MYI may go up as a fraction of the total this year, given the overall drop in extent relative to 2010, and the loss of MYI in the Beaufort and Chukchi seas, there's a good chance that it'll be lower in absolute terms. Right now I think it's going to depend on whether the concentration of "slush puppie" ice in the Siberian sea (which is being held up by residual MYI according to Julienne Stroeve) drops low enough for it to fall off the record. It's only £50 though, so I'm not going to cry if I lose.

RunInCircles

I enjoy the experience of following Chris and Paul as they explore and learn about the arctic and how it is measured and what the reports mean. Paul & Ned If you have a problem with the content of their post why don't you just not read them. I would like to continue to read them although I think I will skip your posts complaining about the other posters.

L. Hamilton

Just a sign of my fuzzy thinking but I find myself able to nod in general agreement with Paul's shifting frames and Ned's straight numbers, with Chris' colorful descriptions and Peter's reasonable cautions, even as y'all disagree with each other.

But I'm distracted by another question today. We're less than 60k above an historical record on either CT SIA or UB SIE. With all these different ways of knowing, what's happening right now on the ice?

www.google.com/accounts/o8/id?id=AItOawkpUaD_uYjZAIrhpA6AA5KyEs-CSoL4zlM

Hi Neven,
Obouy #4 seems to be on the ice now and is operational:

Webcam OBuoy#4

Chris K

Neven

Thanks, Chris K! It's on the Webcam page.

Just a sign of my fuzzy thinking but I find myself able to nod in general agreement with Paul's shifting frames and Ned's straight numbers, with Chris' colorful descriptions and Peter's reasonable cautions, even as y'all disagree with each other.

Thanks for putting my thoughts into words, Larry.

Neven
I was dumb and bet Goddard on his own territory - that there would / would not be an increase in MYI this year

Right. I thought you bet that there would be a new IJIS record minimum SIE, because I believe I saw you commenting there at the time.

We'll have to see about the MYI. Intuitively, it would be weird to have more MYI than last year, seeing that this year is going to go quite a bit below 2010's area and extent. But I guess it's possible.

Phil263

May be this headline might ( briefly) draw some attention to the vanishing Arctic sea ice !

Paul Klemencic

OK... MASIE just updated their numbers. They show a massive one day loss of 146k for day 249 (Sept 6) to 4.59 million.

If the data is actually for August 31, six days earlier, it matches the huge extent loss observed on that day. I was expecting a loss of about 100k for August 31. The biggest losses were in the Beaufort (27k) and E. Siberian (60k) as we observed at the time. My estimate based on Bremen and NSIDC extent levels was a somewhat high for August 30, though.

NSIDC sent me an email reply, and indicated they checking into the dating issue, but their project lead is out on vacation this week. They will address the issue next week.

L. Hamilton

UB did indeed drop 111k on 8/31, but even more (114k) on 9/5. Either way, you're inclined to think the MASIE result is not predictive for tomorrow?

Who's the project lead at NSIDC? Just curious, I was exchanging emails with someone else there this morning.

Paul Klemencic

Larry, I am exchanging emails with Kara in the NSIDC User Services group, and she didn't say who the project lead was for the MASIE project. I can try and work that into the next email exchange.

Paul Klemencic

Oops, in my comment above regarding MASIE I said "my estimate for August 30 was somewhat high ... " . Wrong.

It should read "my estimate for August 30 was somewhat low.." compared to the MASIE report for day 247 and 248.

Larry, no, MASIE isn't very predictive, not until they tighten the timing up (as well as fix the dating). But still quite useful to see which region the ice was lost in, and thus assess the pack in each region.

And when the fix the dating issue, we should have a very accurate and double checked ice extent measurement. MASIE could give us the best and most detailed assessment of the ice pack extent.

Ned Ward

To be specific, Paul, you had made two predictions:

Day 247 was going to be between 4.60 and 4.66.

Day 248 was going to be a 100K drop from 247.

Both predictions appear to have misfired spectacularly -- Day 247 was 4.77, and the drop from 247 to 248 was 50K, not 100K.

Perhaps you could adopt a little more humility and openmindedness about the NSIDC and IJIS products? Maybe a little less certitude about your claims?

Daniel Bailey

With all due respect, Ned, perhaps you could model the behavior you demand from Paul.

    "misfired spectacularly"
    "adopt a little more humility and openmindedness"

Physician, heal thyself.

I, for one, am interested in seeing what comes from Paul's line of inquiry and analysis; being dismissive of the results before the research has run its course speaks less of an open mind and more of a rush to judgement or an agenda.

Phil263

on the UB map, it looks like the "hole" North of the Laptev Sea is now filling up. OTH in the ESS , the hole seems to be getting larger, in fact the whole "peninsula" looks like it is about to desintegrate completely!

L. Hamilton

Ned, if Paul based those predictions for 247 and 248 on the Bremen maps, he wasn't doing half bad.

A Rambler

Sorry if this is the wrong place to ask, but is there any underlying meaning to 15% ice coverage (even barring all the complications with sensing and calculating), or is it completely arbitrary? If it is arbitrary, shouldn't more attention be focussed on physically meaningful measures?

Patrice Monroe Pustavrh

A Rambler, as far as I know the extent uses 15% threshold because the measurement in area can be wrong due to melt water ponds, wet snow etc. The value is arbitrary, but it has been chosen because below this level, it is more likely that open water would be measured as ice and above it, ice can be measured as open water. Note that this threshold is on the "pixel" level - the resolution of scanner. And also note, that DMI uses 30% threshold.
So, extent and threshold values has been chosen in order to remove some of the errors in measurement in area and to get more consistent results. More accurate measurement would be well appreciated, but so far, this is the most reliable measure we have. Note also, that pixel size is between 6.25x6.25 km and 25x25 km, depending on which sensor is used.

A Rambler

Thanks Patrice. So you're saying it's an arbitrary threshold intended to reduce measurement error. That's not exactly comforting. Is it a reasonable estimate of the overall physical state of the ice, or the ability of the ice to reflect sunlight, or even the usefulness of the ice as polar bear habitat, for example? If say the entire arctic were covered in 20% ice, how would that compare to say one quarter of the area covered in thick multiyear ice? What's the correlation, if any, between SIE and the actual health of the arctic ice system? Basically, if it's just an arbitrary threshold to reduce noise, should I care about it? All this emphasis on whether some arbitrary measure will beat or not beat the level in 2007 seems strange. If everyone's so convinced that the health of the ice is worse than 2007, why not use a measure that more directly reflects that health? Surely we have the technology?

Patrice Monroe Pustavrh

Well, about the threshold, it is not completely arbitrary though, it is constrained to values where you can reliable detect whether pixel has some ice within or not (so, you cannot put your threshold to low, neither too high, but you can vary it a little bit around some value). And note that sensors are capable of detecting only percentage of ice cover within pixels, but not very accurate percentage. So, measurement cannot tell you if there is 1 or 2 meters thick ice within pixel. And you should note that ice is not really randomly dispersed around Arctic, you will find quite solid ice pack north of CA/Greenland and towards Siberian cost and areas of really open water in southern seas north of Siberia/Alaska and somewhere in between, there will be some ice which is really dispersed (check slush puppie on this site). So all in all, extent will give you good image, how large area of Arctic ocean is covered by ice.
So, although there is thickness ommited from measurements and some errors given, the value measured will give you relatively good picture of what is going on with ice as the distribution of ice is averaged over many years.
Of course, and you are right here, volume would be preffered measure. But it is really, really difficult to measure it, as you have to measure it on max few cm level from distance of more than 700 km and so far, we had only limited measurement of it (ICESat from 2003-2007) and now we are waiting for Cryosat team to finish their calibration. In the mean time, PIOMAS model has been the best tool to estimate thickness and thus volume and it looks like we are now way below 2007. But it is not measurement. The only thing we are measure directly, on daily basis on whole Arctic is extent (and area).
And people are convinced that ice is in worse state than in 2007 because of measuring extent and sporadic measurement of thickness in many places (although limited comparing to whole Arctic), checking PIOMAS model and also by comparing visual images of ice in many, many areas.

Chris Biscan

Bremen only went up because ice consolidated in the Fram today from the sharp winds that caused a massive area to emerge.

Jaxa had a -25K extent drop. There map shows the same thing. Well clearly they use the same data. Either way that area needs to be watched...its not likely it will stay glued together for long.

we will see.

I will do a write up on the 00z models here in a bit.

What Iv'e seen of the GFS is pretty interesting.

Paul Klemencic

OK, Ned I got the day count wrong in that comment, and you win the argument that I made a typo. Congratulations.

Lets look at the original predictions, so here are the original comments from seven days ago:

Ned, since Julianne Strove at the NSIDC commented at WUWT that the NSIDC sea ice extent was 4.66 million on August 30, we should have a very good confirmation of the MASIE delay in posting SIE on Monday (but since that is a holiday in USA) likely on Tuesday.
Commented 7 days ago on SIE 2011 update 18: ten yard line at Arctic Sea Ice

Ned is choosing to believe that the MASIE spreadsheet of NSIDC data is correctly identifying the date that the NSIDC data was taken. I have made, I believe, an almost overwhelming case that MASIE is dating the data six days later than taken. Only one of our theories can be correct. And we will know that on Monday or Tuesday, when MASIE posts the data for September 5; I believe that data will actually be for August 30th, and the ice extent reported will be 4.66 million sq km.
Commented 7 days ago on SIE 2011 update 18: ten yard line at Arctic Sea Ice

I intended the prediction of 4.66 million for August 30 on the MASIE data, and it came in at 4.72, off by about 50k. It seems MASIE could be measuring a bit higher that NSIDC and Bremen measurements... we will see.

The next day, August 31 was the big melt day, and I expected over 100k for that day, based on map observations and the big drop in the Bremen graph, and info from Larry on Bremen. The actual number came in with a 146k loss.

This should be great evidence of a six day dating error in the MASIE database, since large extent losses like that are highly unusual as late as September 6. But unfortunately it isn't quite as overwhelming evidence as I expected, because Bremen showed a 114k drop on September 5.

I wouldn't crow too loud until the MASIE project lead gets back next week, and reviews my email pointing out the problem.
When he does come back from vacation on Monday, September 11 he will arrive in time to see that day's MASIE data show roughly a 100k decline in extent, corresponding to the September 5th Bremen drop of 114k.

I suspect by Wednesday next week, we will see the MASIE dates corrected.

Chris Biscan


Bremen has uptick today. Jaxa would likely of had one as well if it wasn't for the 2 day running average. I would expect a large revision tomorrow am on Jaxa towards a -10 to -15K loss for the 7th.

The 00z models show a continue of melt/compaction.

We might see some quick refreeze inside of the current ice pack...

Possibly see the ESB start to freeze over. I say possible because the cold air won't be there for long and winds will primarily be in a more compacting matter pushing warmer SSTS into the ice.

a few notes:

1. models are remarkably very close over the next 10 days and have started to set into this solution, but always expect changes.

2. the coldest air will be cold enough for top freeze over the ice pack, unfortunitely most of the coldest air sits over the North Pole..this is what it is but we need these cold temps to sit over, everywhere not named the central arctic.

3. the models keep under estimating the warm air intrusions and always back off on the extent of the cold air, I guess this is climo. I figure this will change soon. However right now wam air keeps being pumped into the Barrents.Laptev/Kara.

4. The cold air on both models by day 4 gets pinched to the central arctic and modifies on top of that both models have a strong DPA. with an HP sitting over Canda and SLPs lined up over the East Central Arctic or towards Russia pending how you look at it. On top of that they do not want to open the Fram up for business.

5. Both models including the umket and gem have a main SLP over the central arctic with the cold and and compacting wind on both sides of the arctic.

They also torch the Western Arctic which is already experiencing near record warm temp anomalies. not as intrusive as 2007 on the Russian Side.
but the Beafort, Chukchi, and into parts of the ESB/Western Arctic will see 2C to 10C 850s for a week.

The Barrents torches the entire time with the 0c 850 line now staying basically along or just off the Atlantic side of the ice pack with SPS in place to keep this air in place and move it towards the Kara/laptev before cooler air filters in.


all in all if this prevails I have a hard time seeing 2007 not being beat. On top of that I would expect Bremen and NSIDC possibly go below 4,000,000km2. Jaxa could also experience record drops this late.

It will all depend on how much of these temps and winds pan out and how much freeze can offset the ideal compacting conditions all over the arctic.

Peter Ellis

Rambler: The point of the 15% threshold is that historically the pack used to be reasonable well consolidated throughout the melt season. You'd have the central pack of 80%+ concentration, then a thin marginal melt zone of something like 50% concentration, and then open water, with the transitions between each zone being reasonable well defined. The 15% threshold is thus tuned to detect the threshold between the melt zone and the open water. Because the transition zones used to be narrow, choosing a threshold of 15% or 30% didn't make a lot of difference.

With today's slush puppy pack, you have areas of fragmented ice as far North as the Pole itself (at least we did last year), and instead of a well-defined marginal zone we have vast areas of loose, low concentration ice.

We can see this globally, with new CAPIE (compactness) record lows being set year on year - but even more important is the distribution of this change in compactness. It's not that compactness has dropped by 5 or 10% across the board, it's that the marginal zone has expanded several fold.

Peter Ellis

OK, I've had a closer look at some MASIE data in comparison to Bremen maps, to see if I can track down this 6 day lag Paul K talks about. I'm afraid I'm still not convinced. The MASIE plots and Bremen plots simply don't overlap well enough to make that kind of claim. It's much more consistent with the scenario I outlined, where different sensors and processing algorithms are better at picking up different types of ice.

Let's take an example we're all interested in: the Northwest Passage. As yet there has been no announcement that the main Parry channel is open: what gives?

Bremen maps have had it wide open since around since the 23rd of August, and arguably a couple of days before: compare the following maps.
http://www.iup.uni-bremen.de:8084/amsredata/asi_daygrid_swath/l1a/n6250/2011/aug/asi180-n6250-20110822_visual.png
http://www.iup.uni-bremen.de:8084/amsredata/asi_daygrid_swath/l1a/n6250/2011/aug/asi180-n6250-20110823_visual.png

IJIS maps had it very nearly open on the 25th of August, but there's a narrow strip blocking it that's still just about holding on.
http://www.ijis.iarc.uaf.edu/cgi-bin/seaice-monitor.cgi?lang=e&mode=img&size=L&date=set&y=2011&m=8&d=25
http://www.ijis.iarc.uaf.edu/cgi-bin/seaice-monitor.cgi?lang=e&mode=img&size=L&date=set&y=2011&m=9&d=6

MASIE has more substantial areas of ice in the passage, keeping it closes (or nearly so) in at least three locations:
ftp://sidads.colorado.edu/DATASETS/NOAA/G02186/png/masie_all_r00_v01_2011249_4km.png

Which is right? Well, the Canadian Ice service has boots on the ground, ships in the water, and plane overflights. Their maps are the highest resolution available I can't say for certain that they're the most correct, but they're certainly in the best position to be able to find ice! Their maps (as of Sept 5th) agree most closely with MASIE.
http://ice-glaces.ec.gc.ca/prods/WIS56CT/20110905180000_WIS56CT_0006005701.gif

The egg codes show areas of 10-20% ice (i.e. on the threshold of counting for extent) in the places where MASIE shows ice, and ~40% ice in the strip where IJIS also detects ice. Bremen is picking up neither of these.

I tried looking on the MODIS optical and infrared channels, but the cloud is too thick to see through, at least with my limited experience. Maybe this is somehow affecting the Bremen data?

Going simply by the maps, you'd say that MASIE was "lagging" Bremen by over two weeks in the Northwest passage area. It's not - or at least not provably so: it's just picking up different ice classes in different regions.

Espen

Peter / North West Passage:

Here is the last clear Modis image I could find from September 1. To me the Parry channel looks pretty open but not 100%, so is frightening the Canadian Ice, I dont know :
http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r04c02.2011244.aqua

Seke Rob

On MASIE, after having been off-line for 5 days (the data and chart updates), they did refresh [my] last night, and backfilled days 246-249:
Date, Total NH Chng Day
31-Aug-2011 4737839 -134730
1-Sep-2011 4796031 58192
2-Sep-2011 4814883 18852
3-Sep-2011 4773314 -41569
4-Sep-2011 4771808 -1506
5-Sep-2011 4721212 -50596
6-Sep-2011 4574807 -146405

The last hefty change brought them smack on JAXA (whom I expect to do their 10K up adjustment [my] late afternoon... something in the order they've been doing the last few days).

Though me simple model says now a bottom out at 4.402 million on the 19th [for JAXA], my mind has been saying since predictions were posted on Open Mind [June-ish], we're on a sub 2007 minimum track [for all except maybe Arctic ROOS **]. Our fluid dynamics engineer says so too, now ;>)

** Going by 30% concentration.

Peter Ellis

To me the Parry channel looks pretty open but not 100%, so is frightening the Canadian Ice, I dont know

I don't know either! My point is simply that the differences between MASIE, IJIS and Bremen seem to correlate with real physical features on the ground (well, on the sea), rather than any sort of data processing delay.

Certainly I wouldn't want to steer a ship through that - then again you'd have a hard job convincing me to kayak across a swimming pool! It's worth bearing in mind that even a single pixel of the highest resolution MODIS image (e.g. http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r04c02.2011244.aqua.250m.jpg) is around twice the length and ten times the width of the largest icebreakers ever made. What looks to us no more than coffee scum can still be formidably dangerous.

crandles

Re: "OK, I've had a closer look at some MASIE data in comparison to Bremen maps, to see if I can track down this 6 day lag Paul K talks about. I'm afraid I'm still not convinced."

I thought it was pretty convincing that the correlation peaks at 2 days pretty much as you would expect if JAXA uses 2 day averaging at the cell concentration level while NSIDC use 5 day averaging (presumably also at the cell concentration level as I don't see averaging at the total level makes much sense compared to where it is necessary at cell concentration level). That this doesn't involve the explanations given being wrong is also strong support.

Espen

Peter,

I would not advice to go by Kayak, but the ice you see on that image is mainly coming from the upper part of the CA (north).
Regards espen

Ned Ward

Paul writes: The next day, August 31 was the big melt day, and I expected over 100k for that day, based on map observations and the big drop in the Bremen graph, and info from Larry on Bremen. The actual number came in with a 146k loss.

Paul, the big drop in Bremen's data on 31 August was probably just noise. Much of that "lost ice" reappeared the next day. As I posted in my comment above, here are unofficial versions of the Bremen data (based on processing the daily maps to calculate extent):

8/28/2011 4604492
8/29/2011 4515625
8/30/2011 4502656
8/31/2011 4391601
9/01/2011 4453320
9/02/2011 4512773
9/03/2011 4449921
9/04/2011 4390859

One disadvantage of the Bremen data set is that the data have more noise than IJIS.

Ned Ward

crandles writes: I thought it was pretty convincing that the correlation peaks at 2 days pretty much as you would expect if JAXA uses 2 day averaging at the cell concentration level while NSIDC use 5 day averaging (presumably also at the cell concentration level as I don't see averaging at the total level makes much sense compared to where it is necessary at cell concentration level). That this doesn't involve the explanations given being wrong is also strong support.

Thanks for bringing up the "correlation" issue. (And thanks again for providing the spreadsheet with the past 9 months' MASIE data, by the way!)

I think that's a pretty important point, and in the absence of any better evidence it would seem to lean heavily against the idea of a large lag (e.g., 6 days) in the MASIE data. The differences in correlation between 0, 1, and 2 days' lags are not large, so any one of those could be possible. (For anyone who missed it, correlations between MASIE and IJIS with various lags are given here.)

Do the MASIE data involve five-day averaging, like the SSMI-derived "Sea Ice Index" product? I haven't read enough to know.

I always really appreciate your comments here, and I particularly enjoyed the thoroughness of your explanation for the most recent SEARCH contribution.

crandles

New Area record 2.9174929

Ned Ward

Not trying to beat a dead horse here, and there are probably more interesting things to talk about. But let me just respond to this:

Daniel writes: I, for one, am interested in seeing what comes from Paul's line of inquiry and analysis; being dismissive of the results before the research has run its course speaks less of an open mind and more of a rush to judgement or an agenda.

I'm not sure how closely you followed the last thread (the "ten-yard line" one). My only real criticisms of Paul are based on his repeated tendency to engage in flights of speculation that he then presents as if they were facts.

He seemed to be convinced that IJIS must be averaging over a longer period than their stated two days, that the higher-resolution data products must be more accurate than the lower resolution ones, that the date-stamps on MASIE data must be in error by something like six days, and so on.

I think it's very dangerous to dress up speculation in the language of certainty. Old-timers here may know that Paul's "certainty" should be treated as "possibility", that Chris B's "torching" doesn't actually mean setting the ice on fire, that most of what Ned writes should be ignored [ :-) ], etc. But to a newcomer, this can all be very confusing.

You'll note that I rarely (if ever?) said that Paul's claims were flat-out wrong.

I said that I didn't know how long a period IJIS uses for averaging; that I would be inclined to trust their description of their own process; and that the apparent error Paul thought he had found could be easily explained if IJIS was referring to "averaging" at the grid cell level rather than at the whole-Arctic level.

Likewise, I don't know that there isn't a six-day lag in MASIE, but there seems to be some evidence (from the actual quantitative correlations) against it. I specifically said I was "agnostic" about which data source (MASIE, IJIS, Bremen, etc.) was most reliable.

So perhaps Daniel is right that my responses to Paul's comments over the past week or so have had an "agenda." It's not really a hidden agenda, though. I just think people should be clear about the difference between facts and speculation.

OK, end of rant. Anyone who has read this far can safely forget most of the above.

Neven

New Area record 2.9174929

Thanks, Chris. Post is up.

Chris Biscan

right now there is no other word better then Torching for SSTs. Besides 2007(over a much smaller spatial area) SSTs are crazy warm FOR THE ARCTIC FREAKING OCEAN :)!


Seke Rob

crandles wrote:

New Area record 2.9174929

The 2007 record was set on Sept.7 [straight face smiley]

12 month running CT average & anomaly ending Sept 6, in millions sqkm:

2007: 8.912931 -1.086853
2011: 8.764435 -1.235349
Decline: 148496, twice the global 2007 v 2011 anomaly.

The 365 days anomaly is [ever so] slightly lower than the 2011 249 day which sits now at -1.223588 million sqkm.

Fun with statistics, lets not herald just yet... the Fat Lady is not done yet.

Charts:

Arctic YTD Area Anomaly (CT)

Global 1979-Present (CT)

Watch that red line... 365 rolling 2011 is now only 10.8K sqkm behind on 2007 which hit that low figure in November. (Got charts that are not fit for the you know who public on that... they'd start piping it's all cyclical... still SNAFU though, absent thickness)

P.S. The present global area 1 Day anomaly is -684,000 greater than 2007.

(See that Neven got a new post up on the 1 day Area record... slow typing here :O)

Chris Biscan

http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png


Updated for September 7th.

I get roughly 4,340,000km2 in Photoshop.(+/- 10,000km2)

A Rambler

Ned, fear not: Even to a newcomer like me, it's pretty obvious that Paul's conclusions are speculation, not fact. (And he has repeatedly said as much.) The same is true of most of what is said on this blog or, for that matter, on any blog.

Chris Biscan

The bremen prelim is gonna be interesting today. MODIS is showing some pretty impressive compaction taking place in multiple areas.

Neven

IJIS revision was down (less than 1 km2).

Animations have been updated.

SSTs are crazy warm FOR THE ARCTIC FREAKING OCEAN :)!

:-D

Peter Ellis

Chris B: you have to be very careful in interpreting SST anomalies in areas around melting sea ice.

The surface of open water is by definition above freezing. As soon as it freezes over, the surface temperature is free to drop rapidly to several degrees below zero. Yes, the SST anomalies are huge, but all they are really telling you is that during the reference period that area was ice-covered, and now it's open water: information we already know from the extent maps.

Neven

So many clouds in the Arctic, but will you look at these leads?

during the reference period that area was ice-covered, and now it's open water

That's indeed a very good thing to remember. Was quite an eye opener when you told me this the first time.

Ian Allen

Peter, it seems to me that the base for calculating anomaly for SSTs where frozen in the reference period is -1.7C or something close rather than Ice surface temp, because the anomaly chart doesn't vary where there is still ice, it's always within a degree, so we do still get useful info.
BTW has anyone else been amazed by the persistence of a blob of 11C-12C water W of Svalbard for weeks?

Verify your Comment

Previewing your Comment

This is only a preview. Your comment has not yet been posted.

Working...
Your comment could not be posted. Error type:
Your comment has been posted. Post another comment

The letters and numbers you entered did not match the image. Please try again.

As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments.

Having trouble reading this image? View an alternate.

Working...

Post a comment