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Author Topic: 2016 sea ice area and extent data  (Read 305516 times)

ra3000

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Re: 2016 sea ice area and extent data
« Reply #700 on: August 23, 2016, 10:33:08 AM »
The concentration is very low at some points even within the boundaries of the central Arctic.
Nonetheless, we don't have to forget that we are approaching to the dates of the upsidedowns before the refreezing season begins.
The thing is, that even if the trend is to have less extent sea ice (not only in summers but also recently during the last winters), having a low extent may lead to a early stall.

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Re: 2016 sea ice area and extent data
« Reply #701 on: August 23, 2016, 07:08:14 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.1  3.128940  +84.9 14.819282   +41.8 17.948222
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +25.0  3.175113  -36.4 14.881868   -11.4 18.056981


The only region that can be mentioned is Kara (+15k).

Shadow NSIDC extent is now 5.1012 an uptick of +79.8k. Kara leads with +43k, followed by the CAA (+28k) and CAB (+19k).

The quietness in the Arctic can be judged with the attached delta map.

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #702 on: August 24, 2016, 12:40:01 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.1  3.128940  +84.9 14.819282   +41.8 17.948222
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +25.0  3.175113  -36.4 14.881868   -11.4 18.056981


FWIW, one or more days of increased area isn't a rarity around this time. Just last year, we saw four consecutive days of area growth that lead to 150k of net growth--followed by 16 days of ice decrease in which an additional 523k disappeared. 2012 had a four-day span that saw two large increases and just 15k of area loss, and that was followed by 493k before minimum. And one more: 2007 went through an 11-day span in which area rose by 103k, and that was followed by an 8-day drop to minimum of 257k.

bbr2314

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Re: 2016 sea ice area and extent data
« Reply #703 on: August 24, 2016, 03:44:18 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.1  3.128940  +84.9 14.819282   +41.8 17.948222
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +25.0  3.175113  -36.4 14.881868   -11.4 18.056981


FWIW, one or more days of increased area isn't a rarity around this time. Just last year, we saw four consecutive days of area growth that lead to 150k of net growth--followed by 16 days of ice decrease in which an additional 523k disappeared. 2012 had a four-day span that saw two large increases and just 15k of area loss, and that was followed by 493k before minimum. And one more: 2007 went through an 11-day span in which area rose by 103k, and that was followed by an 8-day drop to minimum of 257k.
The problem is that area is not increasing. The "increases" are clouds or interference of whatever type. Clearly, the Kara is completely ice-free and 15K KM2 of ice did not spontaneously appear along its shorelines. It is just noise and the gains should not be interpreted as legitimate (at least not until we hit minimum).

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #704 on: August 24, 2016, 04:12:32 PM »
The problem is that area is not increasing. The "increases" are clouds or interference of whatever type. Clearly, the Kara is completely ice-free and 15K KM2 of ice did not spontaneously appear along its shorelines. It is just noise and the gains should not be interpreted as legitimate (at least not until we hit minimum).

The thing is, scientists use data. They don't simply dismiss out of hand those they don't like because numbers disagree with what they think or feel they should be. At the end of the season, we can't look at any of the metrics and say, "I don't care what PIOMAS, or IJIS, or NSIDC, or anyone else says; they were all just measuring 'clouds or interference', so the official numbers 'should not be interpreted as legitimate'."

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #705 on: August 24, 2016, 04:43:33 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Tue 2016.6384  -43.1  3.128940  +84.9 14.819282   +41.8 17.948222
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +24.7  3.174887  -36.3 14.881905   -11.6 18.056792
Fri 2016.6466  -86.3  3.088544 -127.7 14.754198  -214.0 17.842742


Regional declines in Laptev (-29k) and CAA (-17k). Also ice area on "Lakes" measured -21k less.

Shadow NSIDC extent is now 4.9823 dropping -118.9k. Regional extent declines in Laptev (-54k), CAA (-46k), Hudson (-22k) and Kara (-20k). The CAB increased by +18k.

The attached delta map shows what the numbers cannot.

bbr2314

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Re: 2016 sea ice area and extent data
« Reply #706 on: August 24, 2016, 05:10:26 PM »
The problem is that area is not increasing. The "increases" are clouds or interference of whatever type. Clearly, the Kara is completely ice-free and 15K KM2 of ice did not spontaneously appear along its shorelines. It is just noise and the gains should not be interpreted as legitimate (at least not until we hit minimum).

The thing is, scientists use data. They don't simply dismiss out of hand those they don't like because numbers disagree with what they think or feel they should be. At the end of the season, we can't look at any of the metrics and say, "I don't care what PIOMAS, or IJIS, or NSIDC, or anyone else says; they were all just measuring 'clouds or interference', so the official numbers 'should not be interpreted as legitimate'."
I am not saying data is bad, I am saying this data is corrupted and somewhat inaccurate. While it certainly has value, that value is lessened when people misinterpret clouds as gains.

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Re: 2016 sea ice area and extent data
« Reply #707 on: August 24, 2016, 05:27:04 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Tue 2016.6384  -43.1  3.128940  +84.9 14.819282   +41.8 17.948222
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +24.7  3.174887  -36.3 14.881905   -11.6 18.056792
Fri 2016.6466  -86.3  3.088544 -127.7 14.754198  -214.0 17.842742


That puts 2016 ahead of 2015 and into 6th place overall. Here's a list of the years in 1st through 5th place, along with how much more ice needs to disappear for 2016 to move into each of the remaining ranks:

5th: 2010: 17k
4th: 2008: 85k
3rd: 2007: 170k
2nd: 2011: 184k
1st: 2012: 855k

I am not saying data is bad, I am saying this data is corrupted and somewhat inaccurate.

So data that are "corrupted" and "inaccurate" aren't necessarily "bad"? Lemme check my dictionary on that one... ;-)

bbr2314

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Re: 2016 sea ice area and extent data
« Reply #708 on: August 24, 2016, 05:32:36 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Tue 2016.6384  -43.1  3.128940  +84.9 14.819282   +41.8 17.948222
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +24.7  3.174887  -36.3 14.881905   -11.6 18.056792
Fri 2016.6466  -86.3  3.088544 -127.7 14.754198  -214.0 17.842742


That puts 2016 ahead of 2015 and into 6th place overall. Here's a list of the years in 1st through 5th place, along with how much more ice needs to disappear for 2016 to move into each of the remaining ranks:

5th: 2010: 17k
4th: 2008: 85k
3rd: 2007: 170k
2nd: 2011: 184k
1st: 2012: 855k

I am not saying data is bad, I am saying this data is corrupted and somewhat inaccurate.

So data that are "corrupted" and "inaccurate" aren't necessarily "bad"? Lemme check my dictionary on that one... ;-)

...did you read what I said?

RoxTheGeologist

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Re: 2016 sea ice area and extent data
« Reply #709 on: August 24, 2016, 06:25:19 PM »

There is noise in data.

https://en.wikipedia.org/wiki/Colors_of_noise

It doesn't make the data 'bad' and you will note that noise can add to or subtract from the underlying signal. Many people have pointed out that looking at day to day data (whether high or low) and making assumptions about the trend is a rather pointless endeavor. Using a moving average (is it Jim who provides that?) lessens the impact of noise.

If there is bias in the data from noise, one assumes that the same potential artifacts are in the data from previous years and have been reported consistently for those years.  It would be an enormously easy way to discredit the information that is carefully gathered if you say, "Well this year we are doing 'this'" without a very clearly defined model and data to show why we are doing 'this'. Then one goes back and changes the model for all previous years so that comparisons can still be made.




Rob Dekker

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Re: 2016 sea ice area and extent data
« Reply #710 on: August 25, 2016, 07:28:09 AM »
There is noise in data.

Thank you Rox.
This noise is clear in Wipneus' latest posts :
Aug 21: Shadow NSIDC extent is now 5.0224 a drop of -163.8k.
Aug 22: Shadow NSIDC extent is now 5.0214  dropping  -1.0k.
Aug 23: Shadow NSIDC extent is now 5.1012 an uptick of +79.8k.
Aug 24: Shadow NSIDC extent is now 4.9823 dropping -118.9k.

Maybe this is why IJIS and NSIDC use multiple-day averages.

As Neven said, this is 'the slowest horse race in the world'.
Let us not get over excited about single day changes.
« Last Edit: August 25, 2016, 07:36:26 AM by Rob Dekker »

Richard Rathbone

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Re: 2016 sea ice area and extent data
« Reply #711 on: August 25, 2016, 03:24:04 PM »
There is noise in data.

Thank you Rox.
This noise is clear in Wipneus' latest posts :
Aug 21: Shadow NSIDC extent is now 5.0224 a drop of -163.8k.
Aug 22: Shadow NSIDC extent is now 5.0214  dropping  -1.0k.
Aug 23: Shadow NSIDC extent is now 5.1012 an uptick of +79.8k.
Aug 24: Shadow NSIDC extent is now 4.9823 dropping -118.9k.

Maybe this is why IJIS and NSIDC use multiple-day averages.

As Neven said, this is 'the slowest horse race in the world'.
Let us not get over excited about single day changes.

NSIDC specifically caution against using daily values for comparison purposes and normally use monthly ones in their analyses.

BornFromTheVoid

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Re: 2016 sea ice area and extent data
« Reply #712 on: August 25, 2016, 04:40:42 PM »
Single day NSIDC extent down 42k, taking us back to 3rd lowest for the time of year.

Both the 5 day trailing average and the single day values are below all previous minima bar 2007, 08, 10, 11, 12 and 15.

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #713 on: August 25, 2016, 04:44:18 PM »
Some here seem to be missing my point; I'll have to chalk that up to a failure of mine to communicate properly. So one more time:

Yes, daily numbers can be noisy. They can be inaccurate. And, if one wishes, they can be discounted. HOWEVER--for purposes of declaring record values, those numbers are literally all we have. More importantly, they're all we've ever had. Now, an intellectually honest person will discount all those daily numbers if they're going to discount any; they won't declare only those numbers that validate their (sometimes) overzealous forecasts as true and correct, and dismiss as "inaccurate" and "corrupt" any numbers that show otherwise. Doing so is called "cherrypicking", of course, and it's --rightly--frowned upon in scientific circles. So, either we reject all minimum/maximum sea ice records based on all daily numbers being suspect, or we reject none, acknowledging that they may or may not precisely reflect reality, but that biases have been accounted for.

Which will it be?

(As a recap, this particular thread began  a few days back when I noted that Wipneus's shadow area numbers had gone up for two consecutive days, and one member responded that area had NOT gone up, based on the fact that Wipneus's numbers for those two days only were corrupt and inaccurate.)

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Re: 2016 sea ice area and extent data
« Reply #714 on: August 25, 2016, 04:54:52 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +24.7  3.174887  -36.3 14.881905   -11.6 18.056792
Fri 2016.6466  -86.3  3.088586 -129.1 14.752838  -215.4 17.841424
Sat 2016.6493 -170.0  2.918591  +26.1 14.778897  -143.9 17.697488


Most of this in the CAB: -146k.

Shadow NSIDC extent is now 4.9397 dropping -42.6k. CAB declined -31k, CAA increased +32k. Small changes elsewhere.

The attached daily delta map has put some colors in the CAB, missing in the last few days.

bbr2314

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Re: 2016 sea ice area and extent data
« Reply #715 on: August 25, 2016, 05:23:44 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +24.7  3.174887  -36.3 14.881905   -11.6 18.056792
Fri 2016.6466  -86.3  3.088586 -129.1 14.752838  -215.4 17.841424
Sat 2016.6493 -170.0  2.918591  +26.1 14.778897  -143.9 17.697488


Most of this in the CAB: -146k.

Shadow NSIDC extent is now 4.9397 dropping -42.6k. CAB declined -31k, CAA increased +32k. Small changes elsewhere.

The attached daily delta map has put some colors in the CAB, missing in the last few days.
Given the false gains this shows despite still attaining a loss of 170K KM2, I think we still have several century++ losses remaining... tomorrow we should clear the #2 spot leaving only 2012 ahead. I don't think it'll stay ahead...

Buddy

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Re: 2016 sea ice area and extent data
« Reply #716 on: August 25, 2016, 07:51:11 PM »
Most of this in the CAB: -146k.

Shadow NSIDC extent is now 4.9397 dropping -42.6k. CAB declined -31k, CAA increased +32k. Small changes elsewhere.

Will be interesting to see where we are in a week or two.....  Mr. Ice Sheet is not looking good these days :(
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magnamentis

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Re: 2016 sea ice area and extent data
« Reply #717 on: August 25, 2016, 08:12:14 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +24.7  3.174887  -36.3 14.881905   -11.6 18.056792
Fri 2016.6466  -86.3  3.088586 -129.1 14.752838  -215.4 17.841424
Sat 2016.6493 -170.0  2.918591  +26.1 14.778897  -143.9 17.697488


Most of this in the CAB: -146k.

Shadow NSIDC extent is now 4.9397 dropping -42.6k. CAB declined -31k, CAA increased +32k. Small changes elsewhere.

The attached daily delta map has put some colors in the CAB, missing in the last few days.
Given the false gains this shows despite still attaining a loss of 170K KM2, I think we still have several century++ losses remaining... tomorrow we should clear the #2 spot leaving only 2012 ahead. I don't think it'll stay ahead...

true that, sure you have seen my post in the "melting season thread, the one about the "Ax" as well as the one with double century drops, the first is already showing and the second was close this time :-)

<Removed last sentence. Stop breeding ego conflicts, and watch the ice. Last warning. N.>
« Last Edit: August 25, 2016, 09:22:41 PM by Neven »
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Neven

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Re: 2016 sea ice area and extent data
« Reply #718 on: August 25, 2016, 09:27:49 PM »
It will be interesting to see whether this century break is followed by others right away, or whether we get some 'false' gains first. With the current weather forecast I do expect CT SIA to go down some more. I'm not sure if it can still catch 2012, as 685K is quite a lot of SIA at this point, but the forecast is pretty insane.

Such a Dipole in June or July... I don't even want to think about how the ice would look right now.
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Random_Weather

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Re: 2016 sea ice area and extent data
« Reply #719 on: August 25, 2016, 09:34:31 PM »
@ Neven

I dont know, i think now where the ice is thin and more open, it becomes more effctive then in June/july, because of more wave forcing and effective energy imput (because of the clouds and warm air).

Its the same thing with the GAC in 2012, this in June would not destroyed so many Extent as it has.

Edit:

But would agree, it should not be enough to beat Area from 2012, but could give the chance to fill the place between 2012 and other years

Neven

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Re: 2016 sea ice area and extent data
« Reply #720 on: August 25, 2016, 09:46:55 PM »
@ Neven

I dont know, i think now where the ice is thin and more open, it becomes more effctive then in June/july, because of more wave forcing and effective energy imput (because of the clouds and warm air).

Its the same thing with the GAC in 2012, this in June would not destroyed so many Extent as it has.

True, but it would cause an enormous amount of preconditioning that would make itself felt in August.

The sun is much lower now, and the cold is coming. The dispersed ice on the periphery (especially the Wrangel arms) would probably be a goner anyway after the GAC. This is going to be a compaction event. Compaction towards the end of the melting season makes a real difference.

But would agree, it should not be enough to beat Area from 2012, but could give the chance to fill the place between 2012 and other years

Yes, this is as good as certain for CT SIA. Already third lowest now, just 14K needed to breeze past 2011.
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AmbiValent

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Re: 2016 sea ice area and extent data
« Reply #721 on: August 25, 2016, 09:47:24 PM »
Area is now below 2007 minimum and barely above 2011 minimum. Second place is almost guaranteed.
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Re: 2016 sea ice area and extent data
« Reply #722 on: August 25, 2016, 10:07:31 PM »

True, but it would cause an enormous amount of preconditioning that would make itself felt in August.

Thats true

The sun is much lower now, and the cold is coming. The dispersed ice on the periphery (especially the Wrangel arms) would probably be a goner anyway after the GAC. This is going to be a compaction event. Compaction towards the end of the melting season makes a real difference.

Yes, but also albedo is higher in June/July, so there is much pot. energy lost direct by albedo, but now, sun is low but not the point, the much more relevant point is, clouds, which gives long-wave energy surface downward, is much less the solar downward in July/june but is more effective now, because the concentration and thickniss is low, mobility of ice is also stronger and because of much summer divergence, it has now very much pot. to compact the ice.



Yes, this is as good as certain for CT SIA. Already third lowest now, just 14K needed to breeze past 2011.

y, should happen with data from tomorrow

Michael Hauber

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Re: 2016 sea ice area and extent data
« Reply #723 on: August 26, 2016, 01:37:17 AM »
Such a Dipole in June or July... I don't even want to think about how the ice would look right now.

Perhaps we could think about how all the open water would look like right now.
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Re: 2016 sea ice area and extent data
« Reply #724 on: August 26, 2016, 01:55:22 AM »
@ Neven

I dont know, i think now where the ice is thin and more open, it becomes more effctive then in June/july, because of more wave forcing and effective energy imput (because of the clouds and warm air).

Its the same thing with the GAC in 2012, this in June would not destroyed so many Extent as it has.

True, but it would cause an enormous amount of preconditioning that would make itself felt in August.

The sun is much lower now, and the cold is coming. The dispersed ice on the periphery (especially the Wrangel arms) would probably be a goner anyway after the GAC. This is going to be a compaction event. Compaction towards the end of the melting season makes a real difference.

But would agree, it should not be enough to beat Area from 2012, but could give the chance to fill the place between 2012 and other years

Yes, this is as good as certain for CT SIA. Already third lowest now, just 14K needed to breeze past 2011.
I've bolded the chief problem we've seen so far this year. In fact, the ice has only recently barely started compacting in the triangle N of Greenland & the CAA. Elsewhere, where it would normally compact, the amount of open water between floes has instead caused it to simply drift, which is *very bad* for the ice.

If you loop MODIS you can see this happening along the edge of the stable triangle, the boundaries of which continue retreating towards the CAA...

The big remaining question is whether the wedge of multi-yr ice now rapidly heading into the Atlantic will be melted out by the coming activity over the Kara or not. I think that is what makes the difference between sub-2M KM2 and 1M (which, I know you ppl may think is crazy, I think is still a possibility).

Rob Dekker

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Re: 2016 sea ice area and extent data
« Reply #725 on: August 26, 2016, 06:22:08 AM »
@ Neven

I dont know, i think now where the ice is thin and more open, it becomes more effctive then in June/july, because of more wave forcing and effective energy imput (because of the clouds and warm air).

Its the same thing with the GAC in 2012, this in June would not destroyed so many Extent as it has.

True, but it would cause an enormous amount of preconditioning that would make itself felt in August.

The sun is much lower now, and the cold is coming. The dispersed ice on the periphery (especially the Wrangel arms) would probably be a goner anyway after the GAC. This is going to be a compaction event. Compaction towards the end of the melting season makes a real difference.

But would agree, it should not be enough to beat Area from 2012, but could give the chance to fill the place between 2012 and other years

Yes, this is as good as certain for CT SIA. Already third lowest now, just 14K needed to breeze past 2011.
I've bolded the chief problem we've seen so far this year. In fact, the ice has only recently barely started compacting in the triangle N of Greenland & the CAA. Elsewhere, where it would normally compact, the amount of open water between floes has instead caused it to simply drift, which is *very bad* for the ice.

I agree. There is not much potential for "compaction" in the Wrangel Island arms. Ice will simply drift around (in still warming ocean water), and yes, that is bad for the ice.

Also, ice "concentration" is idiotically low right already, so much so that I cannot imagine that "area" would fall even further without some really SERIOUS decline in "extent" over the next couple of days.
« Last Edit: August 26, 2016, 06:28:59 AM by Rob Dekker »

Rob Dekker

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Re: 2016 sea ice area and extent data
« Reply #726 on: August 26, 2016, 06:41:47 AM »
I think that is what makes the difference between sub-2M KM2 and 1M (which, I know you ppl may think is crazy, I think is still a possibility).
Yes, I think sub-2M is crazy, and not a serious possibility.
1M is out of the question.

budmantis

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Re: 2016 sea ice area and extent data
« Reply #727 on: August 26, 2016, 06:55:54 AM »
I think that is what makes the difference between sub-2M KM2 and 1M (which, I know you ppl may think is crazy, I think is still a possibility).
Yes, I think sub-2M is crazy, and not a serious possibility.
1M is out of the question.

I have to agree with Rob on this. 2M isn't entirely out of the question but highly unlikely. In other words, it would take an event of such magnitude that it would trump any other event observed in the last ten or more years. Note: I do regret using the term "trump" but it seemed to be the best I could do at the moment.
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Wipneus

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Re: 2016 sea ice area and extent data
« Reply #728 on: August 26, 2016, 09:25:59 AM »

But would agree, it should not be enough to beat Area from 2012, but could give the chance to fill the place between 2012 and other years

Yes, this is as good as certain for CT SIA. Already third lowest now, just 14K needed to breeze past 2011.

It is good you mention it is CT Area, not simply Area. There are a number of reasons not to use CT-Area that I have discussed before.

"Area" calculated from the same NSIDC sea ice concentration using a less questionable method gives sometimes different rankings. For example at the moment 2016 is in second place firmly filling the gap between 2012 and other years:


Date      "NSIDC area"
2015-08-24 3.531752
2008-08-24 3.444459
2007-08-24 3.052184
2011-08-24 3.030930
2016-08-24 2.876135
2012-08-24 2.674178
 

(extracted from https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_nt_nrt_main.txt and https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_nt_final_main.txt.gz)

Nightvid Cole

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Re: 2016 sea ice area and extent data
« Reply #729 on: August 26, 2016, 03:16:35 PM »
Is this real (from ASIG page) ?

Nightvid Cole

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Re: 2016 sea ice area and extent data
« Reply #730 on: August 26, 2016, 03:19:10 PM »

BornFromTheVoid

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Re: 2016 sea ice area and extent data
« Reply #731 on: August 26, 2016, 03:19:59 PM »
Single day NSIDC extent down 90k, but also dropping behind 2011, so now 4th lowest for the time of year.
However, as 2007 and 2011 go went through a temporary stall over the next few days (followed by large losses again), a drop of anything over 20k in the next 2 days will take us to 2nd lowest for the time of year

With regard to previous minima, we are now just 260k and 302k off 2010 and 2008 minima respectively.

Nick_Naylor

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Re: 2016 sea ice area and extent data
« Reply #732 on: August 26, 2016, 04:12:09 PM »
Is this real (from ASIG page) ?

Sure it's real. It just shows what you can clearly see from satellite images: Extent has been hanging in there while area has fallen sharply, because the rubble is widely scattered.
The anomaly is most striking for the 3.125 km chart because that small cell size usually is fine enough so that cells with >15% concentration have significantly more than that on average. Not this year.

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #733 on: August 26, 2016, 04:14:24 PM »
Is this real (from ASIG page) ?

Yup, and it got worse today. Unusual low and late minimum, possibly record low and/or late (for the NSIDC compactness).

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #734 on: August 26, 2016, 04:21:58 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.6438  +24.7  3.174887  -36.3 14.881905   -11.6 18.056792
Fri 2016.6466  -86.3  3.088586 -129.1 14.752838  -215.4 17.841424
Sat 2016.6493 -170.0  2.918565  +56.9 14.809784  -113.1 17.728349
Sun 2016.6521 -109.9  2.808681  -39.9 14.769898  -149.8 17.578579


Most is in the CAB: -85k, also some decline of "lake ice" (-15k).

Shadow NSIDC extent is now 4.8498 dropping -88.7k. Responsible ar CAB (-45k), CAA (-32k) and ESS (-26k).

There is of course an attached delta map to tell you even more.

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #735 on: August 26, 2016, 04:27:56 PM »
Closer to 2012 than any other year.


Date      "NSIDC area"(*)
2015-08-25  3.519381
2008-08-25  3.292974
2011-08-25  3.095398
2007-08-25  3.056328
2016-08-25  2.776879
2012-08-25  2.615146
 

(*) Read my post about when Area is not CT-Area: http://forum.arctic-sea-ice.net/index.php/topic,1457.msg87761.html#msg87761
« Last Edit: August 26, 2016, 06:43:58 PM by Wipneus »

Comradez

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Re: 2016 sea ice area and extent data
« Reply #736 on: August 26, 2016, 06:36:34 PM »
Well...2016 is in 2nd place now.  That was fast.

A couple more century breaks, and 2016 will be breathing down 2012's neck. 

I'm sad that the CT data set is not going to be officially tracked any more.  CT was probably where we were going to see the first sub <1 million reading, which would have raised awareness due to meeting many people's definition of "virtually ice-free arctic." 

bbr2314

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Re: 2016 sea ice area and extent data
« Reply #737 on: August 26, 2016, 08:43:11 PM »
With an official # at 2.8 despite all the clouds, I think the "real" number we would be able to see if IR was perfect would be just about where 2012 is right now... and I anticipate ongoing century drops as we continue pivoting between the sensors' confusion re: clouds and glimpses at the wreckage underneath.

The impending GAC is going to be a whole lot warmer than any we've previously seen, equally as important will be the area it effects, which will be pretty much the entire Arctic (and come D2-3, it will be helped by a second sub-980mb low over Kara!)

Lionrock delivers an impressive burst of Pacific heat immediately afterwards that flows up through Siberia, visible ~D7 on today's 12z EURO, which will further sustain bottom melt (and allow some continuation of top melt).

Given all the above, and the fact that the compaction at the moment is worse than ever before, we already have the momentum for the worst late-season drop in area on record, IMO. By this time 2012 was already solidifying its pitiful remnants into some sort of cohesive blob.... 2016 is not quite there as the impending storm will further reduce the "triangle of fortitude".

Rob Dekker

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Re: 2016 sea ice area and extent data
« Reply #738 on: August 27, 2016, 08:01:50 AM »
With an official # at 2.8 despite all the clouds, I think the "real" number we would be able to see if IR was perfect would be just about where 2012 is right now...

Instead of "IR", I assume that you mean SSMIS or AMSR2 ?

bbr2314

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Re: 2016 sea ice area and extent data
« Reply #739 on: August 27, 2016, 10:48:23 AM »
With an official # at 2.8 despite all the clouds, I think the "real" number we would be able to see if IR was perfect would be just about where 2012 is right now...

Instead of "IR", I assume that you mean SSMIS or AMSR2 ?
Yes :)

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #740 on: August 27, 2016, 03:46:15 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Fri 2016.6466  -86.3  3.088586 -129.1 14.752838  -215.4 17.841424
Sat 2016.6493 -170.0  2.918565  +56.9 14.809784  -113.1 17.728349
Sun 2016.6521 -109.9  2.808624  -40.2 14.769597  -150.1 17.578221
Mon 2016.6548  -56.0  2.752629  +80.0 14.849575   +24.0 17.602204


Responsible are CAB (-44k) and Chukchi (-16k).

Shadow NSIDC extent is now 4.6910 -dropping 158.8k. CAB (-77k), Chukchi (-56k) and ESS (-31k) took the beatings.
2016 is now in second place, taking over 2011 and 2007.

There is an attached delta map where these beatings are painted red.

ktonine

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Re: 2016 sea ice area and extent data
« Reply #741 on: August 27, 2016, 05:00:59 PM »
Now, an intellectually honest person will discount all those daily numbers if they're going to discount any; they won't declare only those numbers that validate their (sometimes) overzealous forecasts as true and correct, and dismiss as "inaccurate" and "corrupt" any numbers that show otherwise. Doing so is called "cherrypicking", of course, and it's --rightly--frowned upon in scientific circles. So, either we reject all minimum/maximum sea ice records based on all daily numbers being suspect, or we reject none, acknowledging that they may or may not precisely reflect reality, but that biases have been accounted for.

No, biases have NOT been fully accounted for.  That's precisely why the uncertainties are so large.  And scientists are constantly discounting data from observations - it's a fundamental part of science.  It has little to do with 'cherry-picking' - just an adequate BS detector.  Even the scientists who collected the FTL neutrino data didn't believe it.  If data doesn't meet a common-sense test or match physical theory and no explanation can be found, THEN physical theory needs revision.  Usually an explanation can be found after further scrutiny.  Spencer & Christy's satellite data showing global *cooling* is another case in point.  The fact this may be the best we have or that it's a helluva scientific achievement to even be able to produce it does not mean you should trust the results beyond the uncertainties stated and even then show some skepticism.


(As a recap, this particular thread began  a few days back when I noted that Wipneus's shadow area numbers had gone up for two consecutive days, and one member responded that area had NOT gone up, based on the fact that Wipneus's numbers for those two days only were corrupt and inaccurate.)

It's worth noting that the three days following the uptick saw 365k in losses.  The gains were a mirage.  bbr's statement that you can't always trust daily numbers was nothing outlandish.  Anyone that follows these numbers knows it's true.  What was the point of criticizing it?

I hesitate to pollute this thread with this type of meta-analysis, but it's become less and less fun to read the comments when more and more I see nothing but harsh criticisms of others *opinions.* 

Iceismylife

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Re: 2016 sea ice area and extent data
« Reply #742 on: August 27, 2016, 05:25:52 PM »
...

 If data doesn't meet a common-sense test or match physical theory and no explanation can be found, THEN physical theory needs revision.

...
That is a mouthful.  I've seen something repeated several times that I lack a physics explanation for.
I hesitate to pollute this thread with this type of meta-analysis, but it's become less and less fun to read the comments when more and more I see nothing but harsh criticisms of others *opinions.*
There are nicer ways of dealing with "problems".

seaicesailor

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Re: 2016 sea ice area and extent data
« Reply #743 on: August 27, 2016, 05:52:29 PM »
Big big drops of extent fellows.
These must be accurate! They adhere well to the established theories around.

seaicesailor

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Re: 2016 sea ice area and extent data
« Reply #744 on: August 27, 2016, 06:03:55 PM »
The Atlantic front is amazing. Even some red, little blue, day after day. Greenland sea melting of ice import is not a tenth as fast. How long will this last?

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #745 on: August 27, 2016, 06:52:43 PM »
Now, an intellectually honest person will discount all those daily numbers if they're going to discount any; they won't declare only those numbers that validate their (sometimes) overzealous forecasts as true and correct, and dismiss as "inaccurate" and "corrupt" any numbers that show otherwise. Doing so is called "cherrypicking", of course, and it's --rightly--frowned upon in scientific circles. So, either we reject all minimum/maximum sea ice records based on all daily numbers being suspect, or we reject none, acknowledging that they may or may not precisely reflect reality, but that biases have been accounted for.

No, biases have NOT been fully accounted for.  That's precisely why the uncertainties are so large.  And scientists are constantly discounting data from observations - it's a fundamental part of science.  It has little to do with 'cherry-picking' - just an adequate BS detector.  Even the scientists who collected the FTL neutrino data didn't believe it.  If data doesn't meet a common-sense test or match physical theory and no explanation can be found, THEN physical theory needs revision.  Usually an explanation can be found after further scrutiny.  Spencer & Christy's satellite data showing global *cooling* is another case in point.  The fact this may be the best we have or that it's a helluva scientific achievement to even be able to produce it does not mean you should trust the results beyond the uncertainties stated and even then show some skepticism.


(As a recap, this particular thread began  a few days back when I noted that Wipneus's shadow area numbers had gone up for two consecutive days, and one member responded that area had NOT gone up, based on the fact that Wipneus's numbers for those two days only were corrupt and inaccurate.)

It's worth noting that the three days following the uptick saw 365k in losses.  The gains were a mirage.  bbr's statement that you can't always trust daily numbers was nothing outlandish.  Anyone that follows these numbers knows it's true.  What was the point of criticizing it?

I hesitate to pollute this thread with this type of meta-analysis, but it's become less and less fun to read the comments when more and more I see nothing but harsh criticisms of others *opinions.*

Of course, I never said "biases have been fully accounted for". 'Fully' was an adjective you added, and it substantially changes the very meaning of what I wrote. I said--and you even quoted it--"biases have been accounted for". When quoting others, please quote directly and with no addition.

Now, it's no secret that the most frequently-used tool in the denialist's Big Bag 'O Tricks is to choose only those data that agree with their preconceived notions. Had you carefully read what I wrote--and perhaps you'll yet do so, if time permits--you'll see that my issue was not with BBR's statement that one can't always trust the daily numbers; my issue was with his/her statement that one can only trust numbers that show a decrease. Surely you're able to see the difference between the two? The simple fact is, virtually every ice metric shows up and down fluctuations near each's annual maximum and minimum. That's simply the nature of things. And it's intellectually lazy--if not a tad dishonest--to pretend that they don't.

I urge you and everyone else here to please not twist my statements or intentions (or anyone else's, for that matter) into something other than what they are.

Thanks! Now go, and pollute no more... ;)
« Last Edit: August 27, 2016, 06:58:50 PM by Jim Pettit »

Xyrus

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Re: 2016 sea ice area and extent data
« Reply #746 on: August 27, 2016, 09:21:59 PM »
Seems to me that the 2016 GATF (Great Arctic Toilet Flush) could potentially be getting ready to take place. The 2016 GPAC (Grand Persistent Acrtic Cyclone) has compacted the ice, and now the dipole is going to come in a flush it out the Greenland meltway.
 
This has certainly been an interesting year in the arctic.

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Re: 2016 sea ice area and extent data
« Reply #747 on: August 27, 2016, 10:01:40 PM »
ktonine, the problem is that bbr2314 said that data showing small gains were 'bad', 'corrupted' and 'innacurate'. When these are then offset by large losses, naturally this data is good, holy and accurate. It's a nonsensical way of thinking, and a tad disrespectful to boot to the satellite sensors that work so hard and do what they do consistently, every year. It is very similar to the way deniers think.

Looking at day-to-day fluctuations and pronouncing value judgements like that, is rookie stuff. That's all. Live and learn.

Let's watch the ice and have some patience before jumping to conclusions.
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budmantis

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Re: 2016 sea ice area and extent data
« Reply #749 on: August 27, 2016, 10:55:04 PM »
Seems to me that the 2016 GATF (Great Arctic Toilet Flush) could potentially be getting ready to take place. The 2016 GPAC (Grand Persistent Acrtic Cyclone) has compacted the ice, and now the dipole is going to come in a flush it out the Greenland meltway.
 
This has certainly been an interesting year in the arctic.

You certainly have a way with acronyms!
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