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Artful Dodger

Nice post, Neven. You're getting good at this! And it's positively eerie how 2010 is tracking 2008 on the 'Compactness' graph, almost a drop shadow... So perhaps if weather is similar this year to the same period in 2008, we'll end up with a similar minimum SIE.

Neven

Thanks, Lodger.

The ice is ready for it, but is the weather ready too? ECMWF is forecasting the lows to take over soon again.

Lord Soth

On todays date in 2008, the loss was only 625 sq km, so 2010 will widen the gap tonight. 2008 only has one century melt left later in the month. I expect 2010 to mirror 2008. Weather will determine if 2010 or 2008 will take second place.

I believe 2007 is now out of reach. There is so many holes in the ice and over such a large geographical area, it is highly improbable that the ice can be compacted enough to overtake 2007.

The point to remember is that we are heading towards a new minimun volume.

FrankD

If 2010 is looking increasingly like 2008, its worth pointing out that of the nine years IJIS data, 2008 had the biggest August melt, and caught up more than 500,000 sq km's on 2007 in less than six weeks from August 1.

It clocked -2,173,750 sq km's extent in August compared to 2004's -2,004,000 and 2007's 1,768,000. 2008 continued to close on 2007 through the first week of September, gaining another 100,000 sq km's by the 9th.

But that was it for 2008 - extent increased on the 10th and the melt was over. The 9th is the equal earliest for the annual minimum to be reached. On average, the minimum is reached on 15th September. 2007, on the other hand didn't stop dropping until the 24th. If 2008 had gone on melting as long as 2007, it probably would have finished within 250,000 sq km's of the record.

Artful Dodger

The IJIS SIE revision for Aug 7 is +5469, making the revised daily change -38,437 for a total SIE of 6,452,813 km^2.

Neven

I have updated the figures. I wasn't sure if I was going to have time for it today, but I did.

Artful Dodger

Hi Neven. When it's convenient, could you add a label with the Current Date to the Compactness Graph? Not urgent, just nice to have in the same way most other graphs are dated. No rush.

Neven

It's on my to-do list. I just have to manually change a column and type in all the dates (boring), unless you know a better way?

Lord Soth

That was only a small revision. We should be back to moderate ice melt tonight, an the lead over 2008 should increase to 200K tonight; taking in account 2008's one day stall.

Artful Dodger

"unless you know a better way"
try entering a date formula in a cell, then make the label a ref to that cell...

Phil263

I note on PIPs that the arrows are still pointing in the wrong direction. Doesn't look that there will be any major uce loss in the coming days. 2010 looks more like 2008 than 2008 as we speak...

Phil263

Oops

I meant 2010 looks more like 2009!

Phil263

IJIS reports SIE change of -47,188 for 8/8 (preliminary).... The question is now: will 2010 stay under 2009?

Neven

2010 looks more like 2009 than 2008 as we speak...

It is indeed looking more and more like it.

siili

Hi Neven, i hope you have/will have time to get some sleep. Even if I and many others love this site, we would like it even more to continue, expanding our knowledge.

I think that this year will in retrospect be a very rewarding one scientifically, with so many new thing happening in the arctic that we hopefully will begin to understand better. How exciting the race is, it will be over in a short time, but what happened will remain with us and, the discussion of that needs a good place like yours.

The difference between different detectots, why models work/don't work, the impact of different types of weather, winds, AO, AD, PDO, AMDO, inflow/outflow of water, what all the new buoys and ships this year saw.

So many things to discuss during the long boring winter...

Finn

You have been found and executed "on the other side of the mirror"!

dorlomin

*waves at our new friends*

FrankD

Well, there goes the neighbourhood!

;-)

Phil263

I just had a peep at the "other side". They seem to be having a ball...

siili

More dancing and spitting on graves then.

There seem to be a new interest in the saying of the founding fathers, I don't know why this springs to mind?

The tree of liberty must be refreshed from
time to time, with the blood of patriots and tyrants.
It is its natural manure.

Well, let the games begin...

Phil263

WUWT looks like of hotch potch of indiscriminate rantings against anything that they find disturbing from Tropical cyclone activity to melting sea ice. They are not in the least interested in the recovery of the arctic ice. Their own " headspace" is to deny that there could be anything that could question our present industrial "capitalist" system.

Lord Soth

Revision for 8/8 is now 50313 sq km, with a revision of 3125 sq km. increased melt.

I have never crunched the numbers, but I believe there is a strong correlation between doward revisions, and increased melt the next night, and upwards revisions to decrease melt the next night.

Its a litlle late in the year to prove my theory, but next year I think I will do a correlation between the revisions and resulting ice melt that night.

We should be heading for increased ice melt tonight.

Artful Dodger

Lord Soth, there is nothing at all that invalidates a hindcast. It's often more useful because of the extra data. So correlate away!

siili

May i make a forecast dearest Lodger? If so i look into my crystal ball and see a big thing in the sky with a certain colour, covering the southern portion of the tounge of old ice beeing pressed out into the varm waters from the mighty rivers by the now mysteriously gone glorious high pressure. And i haven't looked at any optical/IR images, promise!

Artful Dodger

Johann, you need a break.

L. Hamilton

If someone wants to animate ... MODIS shows action since yesterday in that landfast ice along the NE coast of Greenland. Looks like there will be more action to come.

Artful Dodger

Lord Soth said: "We should be back to moderate ice melt tonight".

Good call, LS! Today's change in SIE is -76,094 (b4rev) total now: 6,326,406 km^2.

5-day moving avg is -53,375 km^2/day and 2010 is -91,250 km^2 ahead of 2008.


toby

I had a look at the IARC-JAXA site and it is still showing the figure from the 8th August, altered slightly downward to 6,402,500 km^2 Anyone why why it has not been updated to reflect the melt on the 9th?

toby

The IARC-JAXA site now has the new figures.

1 million more km^2 to equal 2009, then another 0.3 to equal 2006 - at current rates it would be surprising if 2010 does not end in that ballpark, and possibly keep up its lead ower 2008.

I think a record is out of the question - but I could be wrong! Only a complete amateur, after all!

Phil263

Toby

Minimum SIE (IJIS) for previous years are as follows:

2009: 5,249,844 sqkm
2008: 4,718,514
2007: 4,254,431
2006: 5,781,919
2005: 5,422,344

It is likely that we will be under 2006 this year even the adverse weather conditions persist. As you indicate there is still 1 million sqkm to equal 2009 which is about an average of about 33k over the rest of the melting season. From what AD, Anu and others are saying about the present ice condition, it is also likely that we will be under that too.
2008 is still in the balance in my (amateur) opinion .

siili

Don Perovich has released data from one of the Ice Mass Balalance (IMB) buoys of a new type for the more variable arctic able to do work both in ice and water http://imb.crrel.usace.army.mil/2010B.htm but as usual with new machines, the data is not always easy to use for an outsider, but give it a peek.

When the old buoys show jumps in the icedepth, it is usually due to an icebear using it as a scratching stick. And Healy spotted one a few days ago, so who knows?

Artful Dodger

The Beaufort Gyre resumed its clockwise rotation over the past 3 days. Uni-Hamburg ice conc. maps show rotation since 23:00 Aug 7. Drift data from the USCGC Healy confirms eastward motion of the sea ice at 140W 72N at the of rate 80 km/day on Aug 9 18:00 - 22:00. The stationary high pressure system in the region seems responsible.

The High pressure system has now weakened and moved into the E. Siberian sea. A weak low between the Pole and Svalbard should act with the Siberian high to produce South winds today at 85N from 110E to 150E, which would enhance the motion of the gyre.

It will be interesting to see if the rotation of the gyre continues in the short term, and seems highly WX dependent.

siili

I don't think that we should read to much into each update of the details in the reconstruction of the pressurefield, since it is based in essence on a very sparse grid of preasure reporting buoys, complemented with two ships. http://www.sailwx.info/shiptrack/shiplocations.phtml (zoom in on the arctic)

Click on the buoys to see a very nice outline of their movements.

A few days ago, the top preasure was absurdly high at 1050 something hPa, and yesterday it almost vanished. If we look at the models both ECMWF and GFS shows it stable for 3 more days, and they agree on the low over the pole, so both the Gyre and Fram outflow should have a good chance to get going.

Artful Dodger

siili, SLP data is gathered by NASA's Aqua satellite. The 'sparse data' mantra was debunked years ago.

siili

So you think the 1050hPa was real?

Warzypants

The remaining large chunk of landfast ice in NE Greenland has suffered another large-scale collapse according to this latest MODIS image ...http://rapidfire.sci.gsfc.nasa.gov/subsets/?subset=Arctic_r02c03.2010222.terra.250m

Phil263

I have graphed CT SIAs for the period August September over the last five years. As you can see 2010 has now slumped under 2008 in terms of SIA.

Phil263

I meant 2008 is now under 2010 in terms of SIA

JackTaylor

CHANCE to GUESS:
In this image, http://www.polk-nc.com/arctic-Fram-Export-20100809.png
if the area outlined in red "breaks-off / melts through", will it;
1. go through the Fram Strait?
2. go through the Olga Strait
3. Compact up against the main ice sheet

Looks like a nice boat - ready for some "stern first" adventure.

Phil263

Not much melting happening right now :IJIS reports SIE down by 53,437 sqkm for 10 August.
Where is that High Pressure system? Anybody with an update on the weather up there?

Neven

Phil, the high-pressure system is still there, but according to ECMWF it should be moving a bit more to the left and slightly intensify, after which low- and high-pressure systems alternate a bit.

Neven

if the area outlined in red "breaks-off / melts through", will it;

Jack Taylor, I was wondering about that as well here.

Phil263

Neven

Then, if the weather is favourable, why are we seeing such low losses in SIA and SIE ?

Neven

Phil, I wouldn't know. Perhaps SIE and A will go down when the Beaufort Gyre starts turning for real - if it does - and compaction enters the game. Plenty of room for that.

Phil263

I just had a look at the CT website. Ice is only retreating in the Canadian archipelago and to some extent in the Chukchi. It is about stable in the Beaufort but it is increasing in the Laptev and the East Siberian Sea.

Anu

Ice is only retreating in the Canadian archipelago and to some extent in the Chukchi. It is about stable in the Beaufort but it is increasing in the Laptev and the East Siberian Sea.

Remember, the black curves on top are the ice, the red curves on the bottom are the anomalies. If the East Siberian Sea stalls at 300,000 sq km for a few days, that is not "ice increasing" - that is "anomaly increasing", since the amount the area is below the 1979-2008 mean is decreasing for that date in August (but its still way below the mean).

Notice Cryosphere Today does not follow geographical definitions of regions like Beaufort Sea - they just apply an easy mask for processing the data in the Arctic region. Most of that heavy melt in the Beaufort "area" will wind up being in the Arctic Basin as defined by Cryosphere Today.

The Beaufort and Chukchi, as defined by Cryosphere Today, are just about melted away. That huge coming melt will be credited mainly towards the "Arctic Basin" which is already at the level of 2009 at about August 21st.

Phil263

Anu

I think I understand the CT area graphs and I agree the slight uptick in the top curve should be described as stalling of the melt rather than increase in ice area, although in the case of the Laptev sea the uptick is quite pronounced.
This being said,,and this is an innocent question from someone who is abolutely not a specialist in the field, I am a bit puzzled about why considering that the weather conditions seem to be favourable ( I refer to AD's recent comment on this thread), the loss of ice in the last four or five days has been so low. Is it that we do not get a accurate picture of the actual weather on the ground;; or are there other factors than the weather at work here?

Neven

Phil, I would expect things to change, ie see higher daily extent melts, when some big arrows on the PIPS ice displacement map start pointing in the right, clockwise direction.

siili

Maybe slightly off topic, but very interesting to me. When we talk about the present weather situation in the arctic, we ususlly use the Uni-Köln map right? http://www.meteo.uni-koeln.de/meteo.php?show=En_We_We but another look at the same time and place is given by e.g. the initialisation used to start the GFS model http://www.wetterzentrale.de/topkarten/fsavnnh.html

When i compare theese, they are slightly different as i would think from the somewhat ill defined observables. But according to Lodger this is a red herring since Aqua gives us perfect data.

But does not Aqua pass overhead about twice daily, wouldn't that give very good spatial coverage there and then, but rather patchy temporal coverage, four times daily when a preasurefield is given?

I am an absolute beginner in this area with a sincere strive to learn, so please help me out here.

Phil263

Neven

....And it is clearly not the case at the moment, the arrows seem to be all over the place. But these arrows indicate ice displacement which is normally driven by winds, i.e the weather. Am I missing something here ?

siili

I agree that i find the daily numbers puzzleing considering the look of the maps, but the icemovement is very organized at the moment and has been for a few days, if you look at the buoymap http://iabp.apl.washington.edu/maps_daily_arcticbasin.html and compare to the pips2 http://www7320.nrlssc.navy.mil/pips2/idis.html they show coherent motion in the expected directions arroud preasurecenters, clockwise at Highs and anticlockwise at Lows http://www.meteo.uni-koeln.de/meteo.php?show=En_We_We

Neven

Phil, this is my take on it:winds of course are determined by low- and high pressure areas. If I've understood correctly it's at the edges of those systems where the most wind is. For high-pressure areas - anti-cyclones - the wind blows in a clockwise direction, for low-pressure areas - cyclones- the wind blows counterclockwise.

So if we look at that high over the Chukchi Sea (more or less) and we would like to have the PIPS arrows to point in a clockwise manner (signalling an active Beaufort Gyre), we'd want that high-pressure area to move more towards Canada and the Beaufort Sea to have these winds blowing in the right place.

Once that happens in a few days and the arrows point in the right direction, we should be getting more compaction and thus higher daily 'melt' (ice disappearance) rates. There's no guarantee it will happen. It's what my logic tells me should happen.

Phil263

Neven,
Thanks for your analysis, makes sense. We will just have to wait and see!

Artful Dodger

siili, your comment is not a red herring, it is a straw man. My post was about the Beaufort gyre restarting. Instead of discussing that, you have tried to create a false issue about the reliability of weather instruments and methods. First you repeated a long debunked claim about sparse arctic data, then when that didn't work, you now misquote me as if I had ever stated that satellite data needs to be perfect to be both valid and reliable.

What you are doing is rhetoric. Rhetoric is not a scientific method. Deal with the Science: 1. WX maps predicted a strong stationary high in the Beaufort sea. 2. PIPS forecast ice motion vectors consistent with the return or the gyre 3. sea ice concentration maps over 3 days from Aug 7 have confirmed the ice motion. That is how science works. I take no credit for it, I simple reported it to this site. It doesn't depend on me, or any heroic person. Any other scientist can reproduce the result.

Science depends on multiple, robust lines of mutually supporting evidence. No good scientist would depend on a single measure, or be fixated on the grade school like perception that all evidence must fit exactly at all times, or advocate for their favored conclusion in the face of overwhelming evidence to the contrary.

To me, you seem less interested in following the science as you do in demonstrating that you are above it, that you have some special insight which you coyly conceal . So tell us all, what are you really doing here? Do you want to be part of the problem, or part of the solution?

JackTaylor

Neven @ 05:17
"I was wondering about that as well here."
- - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Yes, it was your discussion in that subject which gave me cause to look closer
and if the warm water 'current' from the Atlantic is having a strong effect, another
2 or 3 years could produce an "Ark of a Berg."

Anu

The IJIS SIE correction just came out - they added 7,344 sq km, for a total decrease of 60,781 sq km for August 10.

I fail to see how:
http://www.ijis.iarc.uaf.edu/seaice/extent/AMSRE_Sea_Ice_Extent_L.png
is a reason for celebration at the "Why Underestimate Wishful Thinking ?" crowd...

Neven

The IJIS SIE correction just came out - they added 7,344 sq km, for a total decrease of 60,781 sq km for August 10.

Like Lord Soth says further up this comment section there might be a correlation between downward revisions and increased melt the next night. Let's see what happens.

Many pseudo-skeptics seem to be drunk with joy that those 40 days of melt slowing weather during the whole of July managed to hold off a new record minimum extent for another year. They don't seem to realize that if that hadn't happened we'd now be speculating whether the Arctic sea ice extent could already get under 2 million square km.

I was doubting quite a bit whether PIOMAS was right and the ice perhaps was a lot thicker than thought, but what I'm seeing now at the end of the melting season is slowly killing that doubt. And somehow I think CryoSat-2 data will eliminate the last bit of it. I really don't think there is a recovery.

FrankD

Neven,

You mention the Archipelago as an area of interest, to which I can only agree.

I've just posted a long blather about it over at Patricks but the essence is this. All channels through the archipelago between the NWP and Nares Strait are currently blocked at their north ends. But considering the melt we've seen since 1 July, I would say within five to seven days these will start opening up - the southern line of break up has advanced 500 kms in a month, and is now 50-70 kms south of the Archipelago/Arctic Ocean boundary.

The PIPS arrows have been pointing from the Arctic to the Archipelago most of the Summer (instead of further east towards Greenland and beyond). As the blocks breakdown, ice will start to be exported from the Arctic Basin to the NWP through four channels that are each three times as wide as the Nares Strait. You do the math - this melt season will have a few surprises for us all yet, I reckon.

Jon Torrance

"Like Lord Soth says further up this comment section there might be a correlation between downward revisions and increased melt the next night. Let's see what happens."

The IARC-JAXA extent data web page makes it clear that the initial published number is put out before the satellite has collected data on the whole arctic for the second day that goes into the two day extent average. While it doesn't say anything about what assumptions it makes about extent changes in the uncovered area (easiest I can think of - assume the same percent change as they see in the area that has been covered twice), it does seem reasonable to assume that a downward revision indicates that extent decrease since the last reading the first published number was based on accelerated.

That said, has anyone collected enough data on the revisions to test this idea rigorously? I'm not sure Lodger (as he prefers) and others have documented every single revision of even the last month or so in comments quite that consistently.

siili

Lodger, i truly don't understand where all your anger is coming from, and why you direct it at me? I came to this site to learn, and discuss what i found in the learningprocess to to be interesting, puzzeling or whatever, in the hope to get an stimulating discussion going and increase our communal knowledge. True i am a scientist by training, but in a very diferent field even if some stuff in similar. But if this place isn't big enough for both of us, i'll be a pure observer in the future, Thanks everybody for a good time.

Steve Bloom

I just saw a Reuters report that mentioned (no details) that some scientists are concerned about the new "Russina brown cloud" heating up the Arctic sea ice if the winds shift that way. I suppose that even this late in the season that's a possibility for at least the loow-latitude ice if the weather is otherwise on the clear side.

Anu

I think both Siili and Artful Dodger are reasonable, interesting posters.

Must be some miscommunication, or just a bad night for somebody...

Have a drink, and come back smiling - it's the Summer, after all.

Anu

Another 60,156 sq. km. of sea ice extent gone in the IARC-JAXA dataset:

Despite all wishful claims of "recovering Arctic sea ice", the extent remains 2nd lowest on record, stubbornly below both 2009 and 2008, with about 6 weeks of possible melt/drift left.

(and about 400,000 sq km of blue cloud sea ice concentration melting like an ice cube on a griddle)

Phil263

Anu

Where did you get the data from? There is nothing updated on the JAXA website.

Anu

http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm

"The latest value: 6,273,594 km2 (August 10, 2010) " is not updated properly, but everything else is.
Click on "Data Download":
http://www.ijis.iarc.uaf.edu/seaice/extent/plot.csv
The final data is: 08,11,2010,6213438 (that's 6,213,438 sq km)

Also note the two graphs, sea ice extent and sea ice area are updated (2010/08/11) properly.
Don't be fooled by the "latest value" line being messed up these days...
http://www.ijis.iarc.uaf.edu/seaice/extent/AMSRE_Sea_Ice_Area.png

Evilreductionist.blogspot.com

An average melt (with 'average' meaning 'average from 2005-2009') from here and we get just over 5 million square kilometres (with 'just over' meaning '50,000 over'). I am feeling a little more relaxed about things now, but lots of things are still possible.

Phil263

Thanks Anu

Patrice Pustavrh

Well, from what I've seen on this and Patrick's blog, there are three different measurements for amount of ice: Volume, Area and Extent.
Volume is definitely most important measure, but until Cryosat data become available, we do not have any direct measurement, so we can just estimate it (this is what PIOMAS do).
Area is another measure. It has some drawbacks, since area is only indirectly correlated to volume of ice (think about 1 m3 ice cube and slice this cube into 10 10 cm thick plates and spread those plates. In first case, there would be 1 m2 of area, in second, 10 m2 of area with same amount of ice). However, area measurement is prone to error in satellite measurements and thus, is less reliable in technical sense.
Extent is even more prone to ice distribution. But is most reliable to measure. Thats why is used in ice trends estimation (and for this purpose it is good enough). Extent measure is good for predicting long term trends, since variablities in ice cancel out across longer periods. But for predicting short term recoveries is very very unsuitable and to claim recovery or accelerating melt has no value.
Now, what I think most likely happened this year: We had great spread of ice due to weather conditions in july. This made extent and even area greater than normal comparing to average year. Yet volume is according to PIOMAS model still very low. Now weather conditions are changed and flow of ice is different. Since ice seems to be very mobile, these conditions can lead to greater declines in both area and extent. It remains to be seen until the end of "melt" season, but from what I have seen, speaking of "ice recovery" is not validated with what is actually going on.
Shall we see at least some compactification, the ice area and extent should be way below 2009. Shall the ice be spread around, we may end up above or below in those two measures.

toby

Thanks, Anu, I always check the Jaxa site first thing in the morning - I live in Ireland so I presume the updating is done in Japan, where they are up already! So it spoils my breakfast not to see an update (like this morning!) to the Ice Extent - I always check Neven's site next.

It look like extenet should pass 6 million km^2 in the next couple of days - if the weather remains stable, at least another million km^2 will probably go.

Phil263

DMI has SIE at 2005 level this morning, Arctic Roos show a flat curve, while JAXA and Uni Bremen have the SIE still sloping downwards. NSIDC seems to be inbetween...
If you are a non-specialist and you want to be informed about the state of the arctic, who do you believe? BTW It seems that the "other side of the mirror" has a soft spot for DMI.

Anu

WUWT has a "soft spot" for any website that has recent data that seems to imply an Arctic sea ice "recovery". If there were an undergraduate student at Moscow University running a website from his dorm room PC with graphs of 37% extent that he calculates himself, that showed 2010 higher than 2006, there would be a thread on WUWT prominently featuring graphs zooming in on the "good parts", and complaining about how scientists are "covering up" this groundbreaking "research". And 382 comments taking pot shots at NSIDC and JAXA for getting their algorithms wrong, probably on purpose, unlike this brave, skeptical scientist from Russia.

"Good" data is preserved and trumpeted ...bad data is ignored or minimized.

If the DMI graph of 30% sea ice extent has 2010 drop below 2009, or 2008, in the next few weeks, WUWT will just not mention it anymore. Simple.

If NSIDC and JAXA (the two most respected data sources) have 2010 stay below 2008 and/or 2009 in sea ice extent through the summer minimum, WUWT will attribute it all to freak end-of-summer winds, agree amongst themselves that it is hard to predict the "weather", ignore all predictions which were made based on Arctic climate trends, and move on to talking about Antarctic ice.

toby

Anu, once again you have nailed it. I am a regular watcher at WUWT (sometimes I enter the odd comment) and the site has chopped and changed to suit their own expectations. PIOMAS got replaced in favour by PIPS, an out of date and unsupported system. Cryosphere was flavour of the month until DMI came up with figures that were closer to the "recovery" expectations. I squirm when I read teh site attributing everything to the weather, never stopping to ask just why is Arctic ice so vulnerable to the weather right now?

I am sure even CryoSat-2 data will be discounted for some reason or other when it gets published. Already, the site has been disparaging the GRACE satellite data.

Kevin McKinney

So right. That--to fulfill my role of pointing out the obvious--is why "denialist" fits ever so much better than "skeptic."

Patrice Pustavrh

Updated SIE from IAXA: 08/11/2010 6.205.625
Regarding the difference in ice extent in DMI and IAXA: The difference in graphs using 30% vs. 15% treshold can be explained with ice, which has been extremely spread around collecting into smaller extent. Imagine you have 10x1 m of water, divided into 10 1m by 1m squares and 1 m2 of ice. If ice is distributed evenly across all 10 squares, extent will be 0. But, if ice is distributed for example 30% in first, 30% in second, 20% in third square and 20% in forth, the ice extent at 15% treshold would be 4 m2 and at 30% treshold at 2m2. Now, lets remove 10% of ice from square 4 and move remaining ice in square 4 to square 3. The 15% extent would drop to 3 m2, but 30% extent would increase to 3m2, although we have less ice in water.
Same thing is also happening with volume. Therefore, making any short term prediction about amount of ice going up and down is completely wrong. You cannot say anything about this. However, as you measure ice across longer periods of time, these differences in distribution cancel out and you can see whether ice is dissapearing or not.

L. Hamilton

A few weeks ago, I noticed that Northern Hemisphere temperatures (and GISTEMP in particular) correlated consistently with Arctic ice extent and area. The correlation is strongest for June ice, somewhat less so for September. My guess was that September variations are influenced by winds as well as temperature, whereas June variation depends primarily on temperature. "Temperature" here presumably integrates both sea and air effects, because it summarize the entire Northern Hemisphere (high-North temperatures alone tend to be less effective predictors).

GISTEMP July estimates just came out. For those taking note of such things, it was the warmest Northern Hemisphere July on record. July had the second-lowest NSIDC ice extent, so I was interested to see them together.

July NH temperatures explain about 63% of the variance in July ice extent:
http://img.photobucket.com/albums/v224/Chiloe/Climate/July_extent_temperature.png

Of course, metling is not a one-month process. If we include April, May, June and July NH temps as predictors, the adjusted R^2 improves to 73%:
http://img.photobucket.com/albums/v224/Chiloe/Climate/July_extent_predict3.png

Adding in Tamino's quadratic function of year, which I take here to stand for the "memory" of the system, or thinning ice through previous warm years, the adjusted R^2 reaches 80%:
http://img.photobucket.com/albums/v224/Chiloe/Climate/July_extent_predict4.png

L. Hamilton

So what does this regression approach project for September? Tossing in July extent, along with the quadratic trend and NH April-July temperatures (which together explain 86% of the variance, adjusting for degrees of freedom), yields a predicted September mean between 3.6 and 5.3 million km^2, centered on 4.5.

http://img.photobucket.com/albums/v224/Chiloe/Climate/September_extent_predict4.png

Is that prediction any good? We'll have to wait and see.

toby

All the formal regression analyses seem to predict a number less than 5 million. That assumes that conditions of the forecast are the same as the hindcast. I have my own number of 5.1 stuck in my head for some reason - I think I picked it out randomly some months ago. The equivalent of throwing a dart to get a number! I am not serious about it though, I will defer to the scientific procedures.

L. Hamilton

Toby, I agree the regression approach depends on what happened in the past. It's interesting that this particular model calls the 2007 minimum almost exactly, then overstates the "recovery" in 2008.

If I were making up a number I'd probably pick one higher than 4.5, so as not to look too "extreme." Still, the model says what it says. We can watch and see how that works out.

Phil263

Excellent analysis Larry. Like Toby I have my own prediction somewhere between 5 and 5.3, i.e slightly less than 2009, mainly because of the weather conditions we are seeing this year. This would still fit within Larry's model prediction.

I'd like to know what neven's and everybody else's predictions are..

Evilreductionist.blogspot.com

Phil,

My prediction was for 4.7 - 4.8. I no longer think that we will get there, as the two models that I use (the JAXA average melt and the NSIDC average montly extent) both point to extent of around 5 million square kilometres.

Phil263

Anybody knows what's happened to CT? The image says August 10 but the chart and the data hasn't been updated since August 9.

Neven

I apologize for not commenting so much lately. I had visitors and still have a lot of work. I was able to watch the ice, but not to write about it too much. Comments have been great.

Jon Torrance wrote:

That said, has anyone collected enough data on the revisions to test this idea rigorously? I'm not sure Lodger (as he prefers) and others have documented every single revision of even the last month or so in comments quite that consistently.

I was contemplating doing that at the start of the season, but figured it wouldn't be interesting. I wish I had now though.

Phil263 wrote:

If you are a non-specialist and you want to be informed about the state of the arctic, who do you believe? BTW It seems that the "other side of the mirror" has a soft spot for DMI.

Stick with what you have used from the start, and compare it with sea ice concentration maps and satellite images (from previous years as well). I think that's the fairest way to do it, no matter what your inclination or confirmation bias. Like I've said, I'm using IJIS because of the nice graph and downloadable data.

Despite their differences, in the end all extent graphs will show the same trends.

I'd like to know what neven's and everybody else's predictions are..

After May and July I was pretty sure minimum extent would be under 5 million square km (and was even expecting a new record). Now I'm not so sure anymore, but the incertitude was worse two weeks ago.

I'm impressed with the way Larry Hamilton comes up with a method for predicting September minimum sea ice extent.

Neven

Phil263, like you said: CT area data seems to be stuck at the moment.

IJIS just reported another 60K+ melt: -64219
Let's see what the revision will be today.

Anu

Another 64,219 sq. km. sea ice extent lost today.

My prediction for 2010 has always been "less than 2009" - (and I have always said based on IARC-JAXA sea ice extent data). This will be consistent with Arctic ice that is not "recovering" from the new minimum set in 2007 - there is just annual "noise" around the 30 year trend line. No need to be less than 2007, or even 2008, to establish that the "recovery" since 2007 is just the typical one or two year climb before another dive, that has been happening for the entire satellite era (look at the data). No "PDO cycle" that will take the ice extent higher and higher, back to the 1970's levels (they have satellite data as far back as 1972), as some wishful thinkers believe.

It is interesting to watch the Arctic weather unfold in the summer, and all the twists and turns of melt and drift, and to make little predictions about what might happen in 3 days, or next week - but the fundamental "prediction" is that the planet is warming, the Arctic is warming, and this will lead to less summer sea ice. Yes, the weather can put us slightly above or slightly below the trend line, but the probabilities are clear.

And once the Cryosat-2 data comes in, the probabilities will be even clearer for next summer. I think that trendline slope will continue to drop faster and faster, due to the thinning sea ice. It could turn out that PIOMAS is very accurate, as is Dr. Maslowski.

Chartsgraphs.wordpress.com

2010 has decreased 48,800 km^2 over 2007 DOY values in past 3 days, 16,300 per day. With 43 more melt days, 2010 needs to average 17,000 km^2 more decrease per day to catch 2007.

I find watching the daily difference chart link helpful.

Phil263

Anu, Overall I am in agreement with your analysis. The trend over the past 30 years is clear and the noise of the last couple of years does not fundamentally challenge the hypothesis that the arctic sea ice is retreating .
Dr Maslowski seems to have retracted from his earlier prediction that the pole would be ice free by 2013.

Evilreductionist.blogspot.com

Phil,

I am pretty sure that Dr Maslowski's current prediction is for 2016 +/- 3 years.

6 megabyte pdf:

http://soa.arcus.org/sites/soa.arcus.org/files/sessions/1-1-advances-understanding-arctic-system-components/pdf/1-1-7-maslowski-wieslaw.pdf

Looking at PIOMAS, I think that he is going to be right.

Anu

Yes, I was thinking of his 2016 ± 3 years prediction.

I think the whole "2013" thing started with a New York Times story about a presentation of Dr. Maslowski's at an American Geophysical Union meeting, where he said sometime next decade, perhaps as soon as 6 years (this in 2007).
So, the time frame has always been about 2013-2019, back when other researchers were predicting 2050 or 2100.
http://beyondzeroemissions.org/media/radio/dr-wieslaw-maslowski-predicted-2013-ice-free-summer-arctic-five-years-ago-now-he-says-ma
http://news.bbc.co.uk/2/hi/7139797.stm

As expected, Dr. Maslowski is not highly regarded at WUWT (unlike his sometimes collaborator Dr. Julienne Stroeve, who is treated quite respectfully):
http://wattsupwiththat.com/2010/07/05/the-importance-of-concentration/#comment-424317

siili

This is a very captivating subject, and it looks as we we put PIOMAS present about 0.5 *10^4 km^3 remaining ice into Maslowskis graph and interpolate lineary into the future it looks like we are undershooting his most pessemistic graph.

But from his graph, his like most (all?) present models has the last stand of the arctic ice above the CA, with the current fast loss of old ice from there this may not be how the very close future places out.

The ice appears so thin and mobile now that short term weather probably start to play a big role in the way the future plays out and from which way open water closes in on the pole.

FrankD

I've updated my Area/Extent graph to August 10th (it's the area graph dated 12/08/10, but I can only read values to 10/8/10):
http://img808.imageshack.us/img808/4606/areaoverextent100810.png

Between July 29th and August 4th (when we saw a good run, including a century) the extent loss was amplified by compaction - the A/E rose from 0.795 to 0.825. Between the 4th and the 10th, A/E has been dropping again, suggesting that even though the extent losses were slightly less than in the preceding week, melting remains high, with insterstitial patches of water between floes increasing.

The last four years have all seen a significant decrease in A/E around this time, suggesting (not surprisingly) that the pack generally gets looser in early August (rather than melting at the fringes). I wonder whether that downward kick will continue this year?

Neven

Phil and others, PIPS is showing some bigger arrows that follow that high over the Beaufort Sea. We might finally start seeing some compaction.

If the high moves a bit towards Greenland - which is forecasted - the Beaufort Gyre might start to turn again. This combined with a very big cyclone moving to Siberia could cause some late season ice transport. Let's wait and see.

logicman

"We might finally start seeing some compaction."

Compaction can only occur where there is resistance. A tendency to press ice landwards anywhere between the NWP and Fram Strait is likely - in my opinion - to lead to more ice loss through open channels than compaction against shores. If the current flows hold stable, or increase, we should see a sudden dip in the ice extent graphs.

It is highly unlikely - again in my opinion - that any form of efficient compaction can happen this year until temperatures over the Arctic Ocean drop below -1.9deg.C.

I still stand by my 3.5 to 3.8 extent prediction, but as I intimated to Neven before, the term 'epicaricacy' may yet prove to be useful to anyone who is following my posts. :-)

Phil263

CT reports an INCREASE of 50k in SIA yesterday affecting mostly the Laptev and the East Siberian Sea areas and to some extent the Canadian Archipelago. Would this be due to low temperatures up there?

Chartsgraphs.wordpress.com

8/13 makes the 4th day that 2010 has SIE decrease has been greater than the comparable 2007 decrease.

2007 Sum Last 4 days = -186.1
2010 Sum Last 4 days = -255.9
Delta 69.84
Delta avg - 17.46

The 2007 - 2010 gap has dropped below 700,000, it now stands at 699,200. There are still 42 melt days.

2007 averaged 26,800 km^2 decrease for these 42 days.

2010 will break the 2007 record if 2010 averages 43,400 (16,600 more than 2007) for these next 42 days. It's not over yet!!

Daily charts here.

Kelly O'Day

Anu

I was wondering why the sea ice area curve is slowing down (the rate of decrease).

I've never seen such large areas of melt before in the summer.

Look at the Beaufort, Chukchi and East Siberian Sea areas (and north of there - Cryosphere Today defines the Seas as pretty southernly in their northernmost boundaries).

1 degree of latitude = 111.12 kilometers. Some of those melt areas are 4 degrees of latitude in height, that's about 450 kilometers of sea ice all melting at the same time - and much wider than 450 kilometers.

If the sea ice is much thinner than usual this summer (at least in these very large areas of simultaneous melt), that means the draft of the ice - 7/8 of the total ice thickness, the average depth of the sea ice under water - might be offering little resistance to the sun-warmed waters diffusing much farther than usual underneath the sea ice. If the warmest water is confined to the top half meter or so, and sea ice draft at this time of the year is 20 or 30 cm less than usual, perhaps the warm water has penetrated much farther under the ice than usual - melting much more ice all at once than the usual step by step melting of the sea ice coasts. Rather than melting little bands of sea ice coast completely, step by step, perhaps the melt is the same volume of ice, but an entire thin ice sheet at once. Perhaps a 500 km by 500 km section will melt through completely on the same day after five days of melt, rather than 100 x 500 each day, as in summers past... for example.

Just speculation - I can't find good sea ice thickness data for these Seas, although this site seems very interesting:
http://imb.crrel.usace.army.mil/
They have both drifting buoys, and seabed floor moored upward looking sonar that can measure both ice draft and ice motion (doppler measurements), giving spot measurements of sea ice thickness (as the ice drifts by overhead) for many years. One graph shows that sea ice thickness plummets most Septembers and Octobers at some floor moored positions in the Beaufort and Chukchi Seas - to the 20 and 30 cm thickness range. Perhaps this very thin sea ice is more widespread this season than ever before, which would lead to different sea ice area/extent graph behavior at the end of the melt season.

Phil263

"I was wondering why the sea ice area curve is slowing down (the rate of decrease)."

According to CT, Increase in ice area or at least stalling in the decrease seem to be happening across all areas which still have ice except the Chukchi. This seems to rule out the possibility that ice is moving across. Is it possible then that thick ice may spread out as it is melting and thinning out due to various factors such as currents and winds?

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