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Author Topic: 2016 sea ice area and extent data  (Read 277411 times)

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #650 on: August 17, 2016, 01:49:12 PM »
ADS-NIPR (IJIS) Extent:
5,173,737 km2 (16 August)
Down 8,768,770 km2 (62.89%) from 2016 maximum of 13,942,507 km2 on 29 February.
1,996,282 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 109,341 km2 (-2.07%) from previous day.
Down 482,442 km2  (-8.53%) over past seven days (daily average: -68,920 km2).
Down 1,264,373 km2  (-10.33%) for August (daily average: -79,023 km2).
1,103,958 km2 below 2000s average for this date.
187,131 km2 below 2010s average for this date.
296,907 km2 below 2015 value for this date.
706,946 km2 above 2012 value for this date.
Lowest year-to-date (01 January - 16 August) average.
3rd lowest August to-date average.
3rd lowest value for the date.
128 days this year (56.14% year-to-date) have recorded the lowest daily extent.
35 days (15.35%) have recorded the second lowest.
39 days (17.11%) have recorded the third lowest.
202 days in total (88.6%) have been among the lowest three on record.


CT Area:
3,335,018 km2 (16 August [Day 0.6246])
Down 9,586,340 km2 (74.19%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
1,101,009 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 169,714 km2 (-4.84%) from previous day.
Down 334,416 km2 (-9.24%) over past seven days (daily average: -47,774 km2).
Down 946,208 km2 (-8.5%) for August (daily average: -55,659 km2).
1,048,044 km2 below 2000s average for this date.
365,189 km2 below 2010s average for this date.
259,835 km2 below 2015 value for this date.
392,672 km2 above 2012 value for this date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' shadow area numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!


BornFromTheVoid

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Re: 2016 sea ice area and extent data
« Reply #651 on: August 17, 2016, 03:53:37 PM »
With a drop of 136k, the daily NSIDC extent has dropped back to 2nd lowest for the first time since July 7th.
Just 263k required for the daily extent to drop below the minima of 2009, 2013 and 2014.

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #652 on: August 17, 2016, 05:17:09 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Tue 2016.6192  +23.1  3.581084 +131.4 14.121924  +154.5 17.703008
Wed 2016.6219  -76.4  3.504732 +105.6 14.227520   +29.2 17.732252
Thu 2016.6247 -169.7  3.335046  +84.3 14.311867   -85.3 17.646913
Fri 2016.6274  -74.5  3.260497  +74.3 14.386207    -0.2 17.646704


With the contributions of the CAB (-45k) and ESS (-17k).

Shadow NSIDC extent is now 5.2515 dropping -135.1. Done by the CAB (-72k), ESS (-26k) and CAA (-15k).

The attached delta map takes allows another view.

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #653 on: August 17, 2016, 05:35:21 PM »
If 2016 area loss were to end now, shadow SIA would still be in 7th place. Here's a list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 167k
5th: 2010: 189k
4th: 2008: 257k
3rd: 2007: 342k
2nd: 2011: 356k
1st: 2012: 1027k

seaicesailor

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Re: 2016 sea ice area and extent data
« Reply #654 on: August 17, 2016, 07:02:41 PM »
It is outstanding that almost no blue appears either in the Atlantic or the Pacific side on the last two concentration maps above. Only Laptev edge shows some.

jdallen

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Re: 2016 sea ice area and extent data
« Reply #655 on: August 17, 2016, 07:31:50 PM »
It is outstanding that almost no blue appears either in the Atlantic or the Pacific side on the last two concentration maps above. Only Laptev edge shows some.
That drift map is really awful for the ice.  Everything along the edges is being dispersed into much warmer water. Laptev ice is being driven into warm near shore. Chukchi and near-CAB is driven towards warmer Chukchi and Beaufort water.   All across the Atlantic side, from the Fram to past Franz Josef, ice is being driven towards water that is 1 to 10+(!)C above normal.   And all the while more heat is being drawn up from depth in the middle of the pack.

Noted elsewhere, that heat anomaly in the Barents and Kara may be key to maintaining the strength of the current Cyclone.  NOAA image provided for reference.
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BornFromTheVoid

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Re: 2016 sea ice area and extent data
« Reply #656 on: August 18, 2016, 04:15:14 PM »
Surprisingly, a small increase in the NSIDC daily extent was recorded yesterday, +11k.

So we're back to 3rd lowest again, and over 700k off 2012.

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Re: 2016 sea ice area and extent data
« Reply #657 on: August 18, 2016, 04:30:48 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.6219  -76.4  3.504732 +105.6 14.227520   +29.2 17.732252
Thu 2016.6247 -169.7  3.335046  +84.3 14.311867   -85.3 17.646913
Fri 2016.6274  -74.5  3.260544  +73.9 14.385759    -0.6 17.646303
Sat 2016.6301  -31.6  3.228956  +39.9 14.425620    +8.3 17.654576


Declines in the CAB (-25k) and Greenland Sea (-15k). The area in the CAA increased by +20k.

Shadow NSIDC extent is now 5.2616 an increase of +10.1k. That is due to an rebound in the CAA (+60k). CAB continued its decline with -46k.

As always there is the attached delta map which shows the data in another way.

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #658 on: August 18, 2016, 04:53:03 PM »
If 2016 area loss were to end now, shadow SIA would still be in 7th place. Here's a list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 136k
5th: 2010: 157k
4th: 2008: 226k
3rd: 2007: 310k
2nd: 2011: 325k
1st: 2012: 995k

On a related note: were the remainder of the SIA melt season to proceed exactly as 2013 did from this point onward, 2016 would set a new record.

Juan C. García

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Re: 2016 sea ice area and extent data
« Reply #659 on: August 18, 2016, 06:05:42 PM »
If 2016 area loss were to end now, shadow SIA would still be in 7th place. Here's a list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 136k
5th: 2010: 157k
4th: 2008: 226k
3rd: 2007: 310k
2nd: 2011: 325k
1st: 2012: 995k

On a related note: were the remainder of the SIA melt season to proceed exactly as 2013 did from this point onward, 2016 would set a new record.

Good data Jim! Thank you!
Which is the best answer to Sep-2012 ASI lost?
50% [NSIDC extent vs 1979-2000] or
80% [Orig. PIOMAS volume vs 1979, 77.6% with corrections]

Volume is harder to measure than extent, but 3D is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC official trends underestimate the real speed of ASI lost.

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #660 on: August 19, 2016, 04:51:22 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.6247 -169.7  3.335046  +84.3 14.311867   -85.3 17.646913
Fri 2016.6274  -74.5  3.260544  +73.9 14.385759    -0.6 17.646303
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204134  +98.6 14.523893   +73.9 17.728027


It is all in the CAB: -29k.

Shadow NSIDC extent is now 5.2082 dropping  -53.4k. CAB is again the major contributor (-59k) while the CAA increases by +16k.

The attached delta map allows another view where the ice comes and where it goes.

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #661 on: August 19, 2016, 05:03:18 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.6247 -169.7  3.335046  +84.3 14.311867   -85.3 17.646913
Fri 2016.6274  -74.5  3.260544  +73.9 14.385759    -0.6 17.646303
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204134  +98.6 14.523893   +73.9 17.728027


Even with that second consecutive below-average drop in area, 2016 would still finish in 7th place were the melt season to end today. But we're getting closer to the head of the pack, albeit s-l-o-w-l-y now; here's a list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 111k
5th: 2010: 133k
4th: 2008: 201k
3rd: 2007: 285k
2nd: 2011: 300k
1st: 2012: 971k

bbr2314

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Re: 2016 sea ice area and extent data
« Reply #662 on: August 19, 2016, 06:29:00 PM »
It is not moving slowly. It is being ripped apart each and every day, the clouds are masking the damage. I would bet that the "real" area is now below all minimums besides 07/11/12.

You can see large inexplicable blue areas flashing back and forth... with AMSR2's data yday and the small decrease today that probably means we are going to see a 150-200K loss tomorrow.

Peter Ellis

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Re: 2016 sea ice area and extent data
« Reply #663 on: August 19, 2016, 06:31:35 PM »
Clouds can make the apparent concentration go down as well as up.  All we can say is that the data are currently noisier than usual.

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #664 on: August 19, 2016, 07:13:47 PM »
It is not moving slowly. It is being ripped apart each and every day, the clouds are masking the damage. I would bet that the "real" area is now below all minimums besides 07/11/12.

You can see large inexplicable blue areas flashing back and forth... with AMSR2's data yday and the small decrease today that probably means we are going to see a 150-200K loss tomorrow.

Oh, I'm not doubting that the ice is disappearing; that's why I stated that the numbers were going down slowly, and not the ice. But the numbers are all we have to go by and refer to. Your "bets" and "probablys" may very well come to pass--in fact, they could be understatements, given what's happening--but, in the end, data rules.

FWIW, 2016 SIA is almost certainly going to end up in that 670k gap where 2nd place awaits...

magnamentis

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Re: 2016 sea ice area and extent data
« Reply #665 on: August 19, 2016, 07:14:17 PM »
Clouds can make the apparent concentration go down as well as up.  All we can say is that the data are currently noisier than usual.

true that, while in times of sharp decline the clouds will hide some of the most recent losses and in times of refreezing and compaction the clouds can hide some of that. since we're in a phase of sharp decline it's quite clear to which side the clouds are impacting the data.
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bbr2314

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Re: 2016 sea ice area and extent data
« Reply #666 on: August 19, 2016, 07:21:03 PM »
It is not moving slowly. It is being ripped apart each and every day, the clouds are masking the damage. I would bet that the "real" area is now below all minimums besides 07/11/12.

You can see large inexplicable blue areas flashing back and forth... with AMSR2's data yday and the small decrease today that probably means we are going to see a 150-200K loss tomorrow.


Oh, I'm not doubting that the ice is disappearing; that's why I stated that the numbers were going down slowly, and not the ice. But the numbers are all we have to go by and refer to. Your "bets" and "probablys" may very well come to pass--in fact, they could be understatements, given what's happening--but, in the end, data rules.

FWIW, 2016 SIA is almost certainly going to end up in that 670k gap where 2nd place awaits...


Why would it almost certainly end up there? I think it will go below 2012...

The key difference between 2012 and this year is that 2012 still had some semblance of structure... when the winds were blowing, sure it compacted like crazy, but the key thing is that it could actually compact.

This is not the case in 2016 except for a very small area N of the CAA/Greenland... everywhere else has lost structure completely! And with no structural integrity there is nothing to "compact" onto. Even last year, we had a 'compactable' base -- this year, the heart of the CAB has seemingly been ripped out, to much ill effect.

I will try and illustrate later, but I've seen a few people bring up the point that this year we are dealing with a surge of warm Atlantic water entering the ATL/Siberian side of the Arctic... and basically disrupting the freshwater lense over much of the Arctic. This would also explain why there has been such sudden and drastic melt over areas that are normally immune...

In any case, the models have now gone more gung-ho with the D2-3 cyclone, with some now pushing it to the strength of the one we just had. Models have gone slightly weaker with the following event, but still indicate potential for 970 or lower.

With the GFS/etc now showing some epic Pacific ridging into the CAB through/past D10, melt season has a long way to go...


seaicesailor

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Re: 2016 sea ice area and extent data
« Reply #667 on: August 19, 2016, 07:37:48 PM »
I would say the pack now has a huge potential for compaction, being at record low levels.
We dont have to wait 10 days for pretty extreme events, this is Tuesday 23 to 25.

bbr2314

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Re: 2016 sea ice area and extent data
« Reply #668 on: August 19, 2016, 08:08:46 PM »
I would say the pack now has a huge potential for compaction, being at record low levels.
We dont have to wait 10 days for pretty extreme events, this is Tuesday 23 to 25.
I think the problem we are seeing this year is there is too much open water for compaction to be effective... eg, if you are "compacting" an extent of 1M SQ KM with an area of 300-400K KM2 (that is also thin), the movement alone makes the ice go 'poof' so instead of a meaningful agglomeration as an end result, you have nothing...

This does not hold for the area immediately N of the CAA & NW of Greenland, but for everywhere else, "compaction" seems to be translating into straight-up melting this yr instead of yielding any positive effects (more structural stability, etc).

jdallen

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Re: 2016 sea ice area and extent data
« Reply #669 on: August 19, 2016, 08:16:05 PM »
I would say the pack now has a huge potential for compaction, being at record low levels.
We dont have to wait 10 days for pretty extreme events, this is Tuesday 23 to 25.
I think the problem we are seeing this year is there is too much open water for compaction to be effective... eg, if you are "compacting" an extent of 1M SQ KM with an area of 300-400K KM2 (that is also thin), the movement alone makes the ice go 'poof' so instead of a meaningful agglomeration as an end result, you have nothing...

This does not hold for the area immediately N of the CAA & NW of Greenland, but for everywhere else, "compaction" seems to be translating into straight-up melting this yr instead of yielding any positive effects (more structural stability, etc).
I'm anticipating that with the remnants of the Wendel Island "bridge" and a large slug of the Laptev. 

What will happen in that scary section of low concentration north of 85 is still uncertain.

That wind flow from the on-coming dipole is bad news, possibly very bad news, for the ice along the Atlantic edge.
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RoxTheGeologist

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Re: 2016 sea ice area and extent data
« Reply #670 on: August 19, 2016, 08:43:38 PM »
I would say the pack now has a huge potential for compaction, being at record low levels.
We dont have to wait 10 days for pretty extreme events, this is Tuesday 23 to 25.

Assuming there is anything left to compact!.. Ice moving towards the Atlantic doesn't seem like a recipe for compaction, just further extensive thinning and melting. As the ice thins I'd assume that the ability to damp swell and waves decrease, and we are looking at fetches of 100's if not 1000's of kms. With a fetch of under 600 km, a velocity of 40 kmh, we can expect a swell inside the Arctic basin of 2-3m depending on the length of time the wind is blowing in the same direction. The wave period will be around 6 seconds, giving a wavelength of something like 60m, and more worryingly, disturbing water to a depth of 30m.




Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #671 on: August 19, 2016, 08:53:32 PM »
Why would it almost certainly end up there? I think it will go below 2012...

One supposes it's theoretically possible for an additional 971,000 square kilometers of area to vanish over the next 3-and-a-half weeks or so, but given how that amount is double the average loss from today through minimum for the last ten years, I wouldn't put any money on it. At least not just yet.


Tealight

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Re: 2016 sea ice area and extent data
« Reply #672 on: August 20, 2016, 12:25:50 AM »
I updated my August forecast with the latest area values and the previous storm only managed to bring sea ice area within +1 standard deviation of my forecast. The next storm needs to be at least as powerful as the last one to force area values into the -1 standard deviation range. Anyone who bets on a new record low this year should probably pray for a third storm in September.
« Last Edit: August 20, 2016, 12:31:41 AM by Tealight »

slow wing

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Re: 2016 sea ice area and extent data
« Reply #673 on: August 20, 2016, 12:42:00 AM »
Tealight, I appreciate you doing the model - and also others who do similar. It's a service to us and can inform us.

Was wondering though, in your forecast model, how much of the warm salty water from the 'Atlantic layer' of the Arctic Ocean did the storm mix in or bring to the surface?

How much of this warm water was from Ekman pumping? How much from wave action?

How much ice will this be melting over the coming days and weeks?

How did you calibrate your model for these effects? How big are the uncertainties in the calibration? In the modelling of the storm?

magnamentis

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Re: 2016 sea ice area and extent data
« Reply #674 on: August 20, 2016, 12:55:14 AM »
all current models are based on past data and experience and while i'm not sayin' it has to happen now (this year), sooner or later we shall see the events that make all models based on previous years appear obsolete, not to say misleading.

of course it's a legit approach while my 2cts are a prediction albeit i'm as close to 100% positive it will be that ways, as one can be :-) let's see.

that said i always did and still vote for a second place, provided that there will be no special events in mid september that will turn things once more upside down like so many times before. after all it depends on the weather while the conditions are set.
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Tealight

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Re: 2016 sea ice area and extent data
« Reply #675 on: August 20, 2016, 03:04:59 PM »
Tealight, I appreciate you doing the model - and also others who do similar. It's a service to us and can inform us.

Was wondering though, in your forecast model, how much of the warm salty water from the 'Atlantic layer' of the Arctic Ocean did the storm mix in or bring to the surface?

How much of this warm water was from Ekman pumping? How much from wave action?

How much ice will this be melting over the coming days and weeks?

How did you calibrate your model for these effects? How big are the uncertainties in the calibration? In the modelling of the storm?


I didn't model any of these effects. My forecast model only calculates the aborbed solar energy and assumes perfect energy transfer from open water to ice. The last storm helped to make this reality but we are still at +1SD so there is more melt potential left.

Storms mostly increase the energy transfer between ocean-ice and (ocean-ice)-Atmosphere, but they don't add any energy to the system. The atmosphere is already sucking energy out of the ocean and as the days go by it will become more and more. Once all melt potential is gone new ice has to form. It is a simple energy input-output equation.

I posted more model details on the Developers corner:
http://forum.arctic-sea-ice.net/index.php/topic,1575.0.html

: magnamentis
all current models are based on past data and experience and while i'm not sayin' it has to happen now (this year), sooner or later we shall see the events that make all models based on previous years appear obsolete, not to say misleading.

magnamentis, your statement is more misleading than any model can be.

Models are not based on past data. They are made to simulate physics that fit past or future data. In other words data is the result and not the source.

As long as a model simulates reality well enough to satisfy the consumer then no one will change anything. If model predictions suddenly fall outside the desired accuracy range then a model developer will improve the model e.g. add a new variable or increase resolution. It will however never become obsolete.
« Last Edit: August 20, 2016, 03:15:46 PM by Tealight »

Nick_Naylor

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Re: 2016 sea ice area and extent data
« Reply #676 on: August 20, 2016, 03:29:32 PM »
Storms mostly increase the energy transfer between ocean-ice and (ocean-ice)-Atmosphere, but they don't add any energy to the system. The atmosphere is already sucking energy out of the ocean and as the days go by it will become more and more.

Are you certain about this?

My uninformed sense is that storms can pull energy from warmer regions into the Arctic and deposit it there by condensation, convection and mechanical work (especially now that there are many polynyas where waves can form). I am open to being contradicted though  ???

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Re: 2016 sea ice area and extent data
« Reply #677 on: August 20, 2016, 05:28:37 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Fri 2016.6274  -74.5  3.260544  +73.9 14.385759    -0.6 17.646303
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204209  +98.8 14.524028   +74.1 17.728237
Mon 2016.6356  -31.9  3.172290 +210.4 14.734400  +178.5 17.906690


CAB decline was -23k, Hudson increased by +16k.

Shadow NSIDC extent is now 5.1862 dropping -22.0k. CAB (-33k) and ESS (-20k) declined but Hudson increased (actually doubled its extent) by +41k.

The progress is visualized in the attached delta map.

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #678 on: August 20, 2016, 05:56:58 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Fri 2016.6274  -74.5  3.260544  +73.9 14.385759    -0.6 17.646303
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204209  +98.8 14.524028   +74.1 17.728237
Mon 2016.6356  -31.9  3.172290 +210.4 14.734400  +178.5 17.906690


The effects of GAC 2016--or is that ARAC 2016?--continue to not be reflected in Wipneus's shadow area numbers; that's now three second consecutive below-average drops in area, as 2012 further widens its already large lead. Having said that, 2016 would still finish in 7th place overall were the melt season to end today. IOW, we're creeping up. Here's the updated a list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 79k
5th: 2010: 101k
4th: 2008: 169k
3rd: 2007: 253k
2nd: 2011: 268k
1st: 2012: 939k

jdallen

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Re: 2016 sea ice area and extent data
« Reply #679 on: August 20, 2016, 06:11:48 PM »
Storms mostly increase the energy transfer between ocean-ice and (ocean-ice)-Atmosphere, but they don't add any energy to the system. The atmosphere is already sucking energy out of the ocean and as the days go by it will become more and more.


Are you certain about this?

My uninformed sense is that storms can pull energy from warmer regions into the Arctic and deposit it there by condensation, convection and mechanical work (especially now that there are many polynyas where waves can form). I am open to being contradicted though  ???

It's the total energy budget in question here, Nick.  While weather will bring heat north, as insolation drops, the best that imported heat can do is balance out the heat being lost out of the top of the atmosphere.   That's what we saw last winter - it doesn't put heat into the ice or water, it slows movement out of the water, so more can go into the ice.

The energy in the atmosphere is dwarfed by that in the Arctic ocean; the latent heat of crystallization in the top 1 meter of ocean if released to the atmosphere all at once would heat it to near boiling.  The only things keeping the ice around are the fact that ~200 Watts/M2 (Neat outgoing longwave radiation map: http://cimss.ssec.wisc.edu/wxwise/gifs/LWALL8.GIF) is leaving the top of the atmosphere every second, and that halo and thermoclines keep most of that heat isolated from the ice.

In view of this, the heat brought at this time of year from further south by weather is a side show.  What's important (and dangerous) is how the storms are redistributing the heat that's already here.
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Iceismylife

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Re: 2016 sea ice area and extent data
« Reply #680 on: August 20, 2016, 07:09:29 PM »
...
Storms mostly increase the energy transfer between ocean-ice and (ocean-ice)-Atmosphere, but they don't add any energy to the system. The atmosphere is already sucking energy out of the ocean and as the days go by it will become more and more. Once all melt potential is gone new ice has to form. It is a simple energy input-output equation.
 ...
Your model assumes no heat transfer from lower layers to upper layers in the water column.  Is that correct?

So how sever a storm is necessary to violate your assumption in a meaningful way?

Nick_Naylor

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Re: 2016 sea ice area and extent data
« Reply #681 on: August 20, 2016, 11:09:01 PM »
It's the total energy budget in question here, Nick.  While weather will bring heat north, as insolation drops, the best that imported heat can do is balance out the heat being lost out of the top of the atmosphere.

OK - so you're saying the storm does transfer energy to the Arctic system from the South, but not enough at this time of year to move net energy balance of the Arctic from negative to positive, and not enough to materially affect the ice. Is that correct?

jdallen

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Re: 2016 sea ice area and extent data
« Reply #682 on: August 21, 2016, 12:21:37 AM »
It's the total energy budget in question here, Nick.  While weather will bring heat north, as insolation drops, the best that imported heat can do is balance out the heat being lost out of the top of the atmosphere.

OK - so you're saying the storm does transfer energy to the Arctic system from the South, but not enough at this time of year to move net energy balance of the Arctic from negative to positive, and not enough to materially affect the ice. Is that correct?
Yes, you've pretty well summarized it.  The heat the storm applies to the ice is already there.
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Tealight

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Re: 2016 sea ice area and extent data
« Reply #683 on: August 21, 2016, 01:41:33 AM »
...
Storms mostly increase the energy transfer between ocean-ice and (ocean-ice)-Atmosphere, but they don't add any energy to the system. The atmosphere is already sucking energy out of the ocean and as the days go by it will become more and more. Once all melt potential is gone new ice has to form. It is a simple energy input-output equation.
 ...
Your model assumes no heat transfer from lower layers to upper layers in the water column.  Is that correct?

So how sever a storm is necessary to violate your assumption in a meaningful way?

It's the total energy budget in question here, Nick.  While weather will bring heat north, as insolation drops, the best that imported heat can do is balance out the heat being lost out of the top of the atmosphere.

OK - so you're saying the storm does transfer energy to the Arctic system from the South, but not enough at this time of year to move net energy balance of the Arctic from negative to positive, and not enough to materially affect the ice. Is that correct?

The problems with storms is that they never affect the whole arctic. They have maybe a radius of 500-1000km where waves, ekman pumping and heat from the south will significantly impact melting, but the Arctic basin stretches over an area of roughly 3300*2800km. A storm on the Atlantic side can't prevent freezing on the pacific side and vice versa. Usually the other side of the Arctic experiences cooler than average conditons because it has cold winds from the north.

Edit: A SuperTyphoon(2200km diameter) is still not big enough to cover the entire Arctic.



« Last Edit: August 21, 2016, 01:56:22 AM by Tealight »

Nick_Naylor

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Re: 2016 sea ice area and extent data
« Reply #684 on: August 21, 2016, 03:05:42 AM »
Regardless of it's physical size, a storm can enter the Arctic with considerable strength - i.e., energy - and the dissipate while over the rubble, effectively depositing that energy there. If the magnitude of that energy is irrelevant to melting ice directly, that's another matter.

Crocodile23

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Re: 2016 sea ice area and extent data
« Reply #685 on: August 21, 2016, 01:37:55 PM »

The problems with storms is that they never affect the whole arctic. They have maybe a radius of 500-1000km where waves, ekman pumping and heat from the south will significantly impact melting, but the Arctic basin stretches over an area of roughly 3300*2800km. A storm on the Atlantic side can't prevent freezing on the pacific side and vice versa. Usually the other side of the Arctic experiences cooler than average conditons because it has cold winds from the north.

Edit: A SuperTyphoon(2200km diameter) is still not big enough to cover the entire Arctic.



 Actually this is a false impression that most people have, due to different map projections and because of the fact that most used are not authalic(equal area) projections, there is the very strong effect of high latitudes to appear having MUCH larger areas from the reality.

E.g here is how USA would appear if it was transferred to the arctic:


(from here: http://thetruesize.com/#/ )

BornFromTheVoid

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Re: 2016 sea ice area and extent data
« Reply #686 on: August 21, 2016, 03:59:05 PM »
Update for the week to August 20th

The current 5 day trailing average is on 5,186,000km2 while the 1 day extent is at 5,022,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,855,000km2, an increase from -1,723,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at +212,000km2, a decrease from +229,000km2 last week. We're currently 3rd lowest on record, the same as last week.



The average daily change over the last 7 days was -72.5k/day, compared to the long term average of -53.0k/day, and the 07, 11 and 12 average of -70.1k/day.
The average long term change over the next week is -44.4k/day, with the 07, 11, and 12 average being -60.1k/day.



The extent loss so far this August is the 5th largest on record. To achieve the largest monthly loss, a drop of at least 99.1k/day is required (requiring ~103.1k/day with with single day values), while the smallest loss requires an increase of at least 40.2k/day (+67.4k/day with single day values) and an average loss requires a drop of 8.3k/day (increase of 8.1k/day with single day values).


BornFromTheVoid

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Re: 2016 sea ice area and extent data
« Reply #687 on: August 21, 2016, 04:19:37 PM »
Using single day NSIDC extent values, 2016 has now dropped below the minima of every year up to and including 2006, as well and 2009 and 2013. It is also within 35k of 2014.

With the 5 day trailing average, 2016 has now dropped below the minima of every year up to and including 2006, and is just 66.2k off 2009.



...Diff....... No of Years.. Percentage
Below 0........ 28............75.7%
0-100k.......... 1.............2.7%
100-250k....... 2.............5.4%
250-500k....... 0.............0.0%
500-1000k..... 4.............10.8%
>1000k......... 2.............5.4%

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #688 on: August 21, 2016, 05:02:45 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204209  +98.8 14.524028   +74.1 17.728237
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.5  3.128512  +84.5 14.818940   +41.0 17.947452


CAB: -23k and Hudson +16k.

Shadow NSIDC extent is now 5.0224 a drop of -163.8k. CAB (-68k), CAA (-32k) and Hudson (-27) took care of this.

Have a look at the attached delta map for some more details.

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #689 on: August 21, 2016, 05:34:48 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204209  +98.8 14.524028   +74.1 17.728237
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.5  3.128512  +84.5 14.818940   +41.0 17.947452


2016 would finish up in 7th place overall were the melt season to end today. The updated list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 35k
5th: 2010: 57k
4th: 2008: 125k
3rd: 2007: 210k
2nd: 2011: 224k
1st: 2012: 895k

Shared Humanity

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Re: 2016 sea ice area and extent data
« Reply #690 on: August 21, 2016, 08:12:46 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204209  +98.8 14.524028   +74.1 17.728237
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.5  3.128512  +84.5 14.818940   +41.0 17.947452



2016 would finish up in 7th place overall were the melt season to end today. The updated list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 35k
5th: 2010: 57k
4th: 2008: 125k
3rd: 2007: 210k
2nd: 2011: 224k
1st: 2012: 895k

Looks like a lock on 4th place with 2nd still a very strong possibility.

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #691 on: August 21, 2016, 08:36:40 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204209  +98.8 14.524028   +74.1 17.728237
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.5  3.128512  +84.5 14.818940   +41.0 17.947452



2016 would finish up in 7th place overall were the melt season to end today. The updated list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 35k
5th: 2010: 57k
4th: 2008: 125k
3rd: 2007: 210k
2nd: 2011: 224k
1st: 2012: 895k

Looks like a lock on 4th place with 2nd still a very strong possibility.

At this point, I will--possibly foolishly--slide all my chips over to 2nd place. My "logic": over the last ten years, the average drop from today through minimum has been 470k, with nine of those ten years seeing enough additional area loss to give 2016 the silver (2007 was the lone holdout; a repeat of that year's remaining decrease would leave 2016 in 4th.)

But, as always, we will see...

bbr2314

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Re: 2016 sea ice area and extent data
« Reply #692 on: August 21, 2016, 10:25:07 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204209  +98.8 14.524028   +74.1 17.728237
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.5  3.128512  +84.5 14.818940   +41.0 17.947452



2016 would finish up in 7th place overall were the melt season to end today. The updated list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 35k
5th: 2010: 57k
4th: 2008: 125k
3rd: 2007: 210k
2nd: 2011: 224k
1st: 2012: 895k

Looks like a lock on 4th place with 2nd still a very strong possibility.

At this point, I will--possibly foolishly--slide all my chips over to 2nd place. My "logic": over the last ten years, the average drop from today through minimum has been 470k, with nine of those ten years seeing enough additional area loss to give 2016 the silver (2007 was the lone holdout; a repeat of that year's remaining decrease would leave 2016 in 4th.)

But, as always, we will see...

I strongly agree that 2nd is a given (though I am still thinking we hit first).

Interesting tidbit re: continued losses of 470K KM2 between now and minimum...

Given how horrible the state of the ice is this year vs previous years at this time, I would think it is an indicator that we will lose much more than 470K KM2.

If we avg losses of -30K/day for another month, we beat 2012... not a high bar to set, esp given forecast for continued cyclones, and the fact that we have much less high concentration/structurally intact ice than '12.

werther

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Re: 2016 sea ice area and extent data
« Reply #693 on: August 21, 2016, 10:44:28 PM »
The flaw in your assumption, bbr, is 1. that a lot of scattered FYI in  the 'Laptev arm', is not in an environment that supports a lot of melt and 2. all that dispersed ice in the Bering sector is remaining MYI, which is quite resistant.
I am sure the quality of the pack is worst ever, but I doubt the rest of this melting season will produce more than 1Mkm2 of further losses.
I still hold my position in the poll on the 3.75-4Mkm2 box, but I think it will be a very narrow hit (3.98 ?).
« Last Edit: August 21, 2016, 11:02:44 PM by werther »

Tigertown

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Re: 2016 sea ice area and extent data
« Reply #694 on: August 21, 2016, 10:52:26 PM »
It will really surpise me if this year does not take over first place minimal area wise. The SIE though, is being stubborn this year. Seaicesailor pointed out on the other thread that we are about to start loosing some chunks of MYI, which could really be setting up an even worse year for 2017.

werther

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Re: 2016 sea ice area and extent data
« Reply #695 on: August 21, 2016, 11:04:25 PM »
Oh sure, SIA is a different matter. The one metric that will be really interesting is PIOMAS volume at minimum.

icefisher

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Re: 2016 sea ice area and extent data
« Reply #696 on: August 22, 2016, 01:54:07 AM »
I agree Werther.  Volume will indeed be very interesting.  Normally, volume continues to decline until late in September or early October but with all the venting from the fractured CAB, volume, extent and area, may all bottom out much earlier than anticipated.  My original dartboard volume guess of 4800 may turn out a little high.  More importantly is the distribution of volume by ice age.  Will the percentage of volume attributable to MYI go up or down compared to trend?

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #697 on: August 22, 2016, 01:01:06 PM »
It will really surpise me if this year does not take over first place minimal area wise.

Prepare to be surprised, then; it's not going to happen. To wit:

--First place for SIA is 895k away.

--No year in the past quarter century has lost that much area from now through minimum. The average over that period: 459k

--There are roughly 20-25 days left in the melt season (the long-term average is 21 days).

--First place would mean a sustained daily loss of 30k-36k.

So, again: not going to happen. There'll be no area record this summer...

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #698 on: August 22, 2016, 04:29:20 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.6329  -24.7  3.204209  +98.8 14.524028   +74.1 17.728237
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  +19.8  3.148739  +99.0 14.918255  +118.8 18.066994


No significant regional area changes, except "Lakes" that increased +29k. Yes, we all know how much ice there is a.t.m. on the Great Lakes.

Shadow NSIDC extent is now 5.0214  dropping  -1.0k. Here we have increases in the CAB (+24k), and CAA (+16k). Declines are found in Baffin (-24k) and Kara (-20k).

In the attached delta map, the quietness in the Arctic Basin can be noted.

Rob Dekker

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Re: 2016 sea ice area and extent data
« Reply #699 on: August 23, 2016, 07:58:17 AM »
The small declines in area and extent from the past couple of days do surprise me.
With the significantly dispersed ice pack (with arms into the ESS and the Laptev) and the resulting low overall ice concentration, I would have expected some significant drops.
Maybe in the days to come ?