Support the Arctic Sea Ice Forum and Blog

Author Topic: 2018 sea ice area and extent data  (Read 589135 times)

gerontocrat

  • First-year ice
  • Posts: 9315
    • View Profile
  • Liked: 3719
  • Likes Given: 28
Re: 2018 sea ice area and extent data
« Reply #2150 on: November 21, 2018, 12:25:01 PM »
JAXA ARCTIC EXTENT 9,972,794 km2(November 20, 2018)

- Extent increase at 105 k is 39 k above the average (2008-2017) on this day,
- Extent is 12th lowest in the satellite record, see Juan's post above for details (and attached table).
- Freezing to date from minimum is 306 k (5.9%) GREATER than the 10 year average extent gain,
- On average (last 10 years) 52.3 % of the increase in extent from min to max is done.

An extra line in the table based on average extent increase in the last 5 years has been added. This is because extent gain in 2012-13 was so large (rebound from record low minimum) that it distorts the average. The outcome from using the 10 year average extent gain from now is a maximum of 14.64 million km2 (760k > 2017).  Using the previous 5 years's average extent gain, the resulting maximum is 14.55 million km2, (670k > 2017).

Extent gain from minimum now well above average.
The late refreeze in late September early October is now just a memory.
GFS indicates that overall the Arctic is at a temperature anomaly of around +2 celsius  for the next few days.

On average (last 10 years) Just half of extent gain from min to max is now done with 113 days to maximum. So who is brave enough to predict the final outcome, given a period of extremely low freezing followed by the reverse?
______________________________________________________________________
ps: *The 2010's average figure I use in the attached table excludes 2018. I exclude 2018 (from all JAXA and NSIDC tables and graphs) so that the difference of the current year with the 2010's decade to date average is not modified by the current year data.
______________________________________________________________________
[/quote]
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Phil42

  • New ice
  • Posts: 71
    • View Profile
  • Liked: 88
  • Likes Given: 716
Re: 2018 sea ice area and extent data
« Reply #2151 on: November 21, 2018, 04:04:44 PM »
Another interesting statistic to show the uniqueness of the current refreeze. The table shows the extent changes (JAXA) in the last 30 days (Oct 21 - Nov 20). 2018 is leading with a margin of over 400'000 km2 and the extent gain was over 1'000'000km2 higher than the 2010's average!

Another note I'd like to make is that the table considers all years from 1979-2018. Out of the years in the top 10, there are 4 from the 2010's, 4 from the 2000's and only 2 from before 2000. This shows that there are times of the year where the refreeze is actually going up, rather than down like the overall extent trend.

My theory, and please correct me if I'm wrong, is that this is the effect of the increased summer melt in the central seas. Especially the CAB, Laptev and Kara lose way more ice in summer than they did 20 years ago. But because of their northern and central location, they still refreeze 100% in winter anyway. But this (usually quite fast) freeze of those seas was around early October 20 years ago, it's now happening in late October and November. Therefore the upwards trend in October - November sea ice gain.

Klondike Kat

  • Grease ice
  • Posts: 842
    • View Profile
  • Liked: 46
  • Likes Given: 56
Re: 2018 sea ice area and extent data
« Reply #2152 on: November 21, 2018, 05:46:02 PM »
To put current events a bit in perspective: The last time the daily JAXA arctic sea ice extent did not rank in the top 11 was 25th April 2012. Since then, every single day was in the lowest 11 at the time - until yesterday.

That's a great signal for the ice. But on the other hand, we all know what happened the months after the last time it was this "high" in 2012.

Interesting.  But every time we "think" we know what is happening, the Arctic throws us for a loop.  Is this just another loop, or something more?

gerontocrat

  • First-year ice
  • Posts: 9315
    • View Profile
  • Liked: 3719
  • Likes Given: 28
Re: 2018 sea ice area and extent data
« Reply #2153 on: November 21, 2018, 05:46:54 PM »
NSIDC Total Area as at 20 November (5 day trailing average) =  8,730,021 km2
Total Area         
 8,730,021    km2      
 349,066    km2   >   the 2010's average.
 526,751    k   >   2017
         
Total Gain____    103    k   
Peripheral Seas    4    k   gain
Central Seas__    51    k   gain
Other Seas___    48    k   gain
         
Peripheral Seas         
Bering _______   -0    k   loss
Baffin  Bay____   -2    k   loss
Greenland____    0    k   gain
Barents ______    6    k   gain
         
CAB Seas         
Beaufort_____   -5    k   loss
CAA_________    0    k   gain
East Siberian__    11    k   gain
Central Arctic_    12    k   gain
         
Kara_________    13    k   gain
Laptev_______    8    k   gain
Chukchi______    13    k   gain
         
Other Seas          
Okhotsk______    0    k   gain
St Lawrence___   -0    k   loss
Hudson Bay___    48    k   gain

Other stuff
GFS says Arctic temperature anomaly at around +2 and staying there for a few days. GFS also saying warmer air moving West to East across N. America greatly reducing extreme cold in Central and NE Canada by early next week. Stormy weather and relative warmth also moving up Baffin Bay and towards NE Greenland.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

jdallen

  • Young ice
  • Posts: 3244
    • View Profile
  • Liked: 520
  • Likes Given: 205
Re: 2018 sea ice area and extent data
« Reply #2154 on: November 21, 2018, 05:46:59 PM »
<snippage>
My theory, and please correct me if I'm wrong, is that this is the effect of the increased summer melt in the central seas. Especially the CAB, Laptev and Kara lose way more ice in summer than they did 20 years ago. But because of their northern and central location, they still refreeze 100% in winter anyway. But this (usually quite fast) freeze of those seas was around early October 20 years ago, it's now happening in late October and November. Therefore the upwards trend in October - November sea ice gain.

Your thinking is along exactly the same line as my own.  Volatility increases as we approach a
change in fundamental system dynamics.

(the last 15 seconds is key to my illustration...)

This space for Rent.

gerontocrat

  • First-year ice
  • Posts: 9315
    • View Profile
  • Liked: 3719
  • Likes Given: 28
Re: 2018 sea ice area and extent data
« Reply #2155 on: November 21, 2018, 06:41:02 PM »
<snippage>
My theory, and please correct me if I'm wrong, is that this is the effect of the increased summer melt in the central seas. Especially the CAB, Laptev and Kara lose way more ice in summer than they did 20 years ago. But because of their northern and central location, they still refreeze 100% in winter anyway. But this (usually quite fast) freeze of those seas was around early October 20 years ago, it's now happening in late October and November. Therefore the upwards trend in October - November sea ice gain.

Your thinking is along exactly the same line as my own.  Volatility increases as we approach a
change in fundamental system dynamics.

I have been wittering on from time to time that the annual minima and maxima are of less significance than the length of time in which the various seas are becoming open water seas rather than icy deserts.  The graphs for the Barents, Kara, Laptev and even the Central Arctic Sea illustrate the trend and are attached. They make it clear how the ice loss is broadening as well as deepening.

The question is whether this change will continue in a gradual fashion, or will there be a sudden transformation of each sea to a mainly ice-free state as may be happening in the Bering and Barents seas.



"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Shared Humanity

  • Guest
Re: 2018 sea ice area and extent data
« Reply #2156 on: November 21, 2018, 07:32:07 PM »
Love these charts. More open water for longer periods means more energy absorbed by the ocean.

Ken Feldman

  • Nilas ice
  • Posts: 1413
    • View Profile
  • Liked: 226
  • Likes Given: 139
Re: 2018 sea ice area and extent data
« Reply #2157 on: November 21, 2018, 08:27:06 PM »
Love these charts. More open water for longer periods means more energy absorbed by the ocean.

Not after September 20th for areas above the Arctic Circle ::)

Brigantine

  • Frazil ice
  • Posts: 129
    • View Profile
  • Liked: 27
  • Likes Given: 141
Re: 2018 sea ice area and extent data
« Reply #2158 on: November 21, 2018, 10:05:59 PM »
Not the same Hudson Bay region as used in other products - This one includes a chunk of the Labrador Sea, and excludes half of Foxe Basin.

But it's at a 25 year high for the date (same week), and by a reasonable margin.

It would have been quite impressive... but then bbr set the anchor at 75%, and there's a long way to go to get there yet  ::)
« Last Edit: November 21, 2018, 10:13:39 PM by Brigantine »

bbr2314

  • Nilas ice
  • Posts: 1817
    • View Profile
  • Liked: 163
  • Likes Given: 53
Re: 2018 sea ice area and extent data
« Reply #2159 on: November 21, 2018, 10:26:58 PM »
Not the same Hudson Bay region as used in other products - This one includes a chunk of the Labrador Sea, and excludes half of Foxe Basin.

But it's at a 25 year high for the date (same week), and by a reasonable margin.

It would have been quite impressive... but then bbr set the anchor at 75%, and there's a long way to go to get there yet  ::)
Yes and oops. I guess general predictions "early refreeze coming in X region" are better than "X will be at Y% by day Z". Live and learn / oh well!

Brigantine

  • Frazil ice
  • Posts: 129
    • View Profile
  • Liked: 27
  • Likes Given: 141
Re: 2018 sea ice area and extent data
« Reply #2160 on: November 21, 2018, 10:53:33 PM »
Specific predictions are good. We like them, and it's a shame none of the doubters made a specific prediction with a number on it (other than "normal" values, and iirc someone said 75% extent on Dec 1st).

Your calibration was just a bit off this time. As if it was a 5th percentile 'highest plausible' value, rather than a 95th percentile confident prediction. This sort of calibration is what the September Prediction Challenge was about - which I very much approve of.

I'm considering making a prediction on whether / how early we'll observe mixing to 400m+ depth in the Sub-Polar Gyre in February/March. If I do make a prediction I'll probably get egg on my face too :P
« Last Edit: November 21, 2018, 11:04:27 PM by Brigantine »

gerontocrat

  • First-year ice
  • Posts: 9315
    • View Profile
  • Liked: 3719
  • Likes Given: 28
Re: 2018 sea ice area and extent data
« Reply #2161 on: November 21, 2018, 10:57:58 PM »
Love these charts. More open water for longer periods means more energy absorbed by the ocean.

Not after September 20th for areas above the Arctic Circle ::)

OK, so not a lot of insolation after Sept 20th north of 66.6, but there is a lot of Arctic sea well below that latitude, and the weather/climate over an open water sea is different from that over an ice desert at any time of year, plus waves etc etc etc.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Juan C. García

  • Nilas ice
  • Posts: 2068
    • View Profile
  • Liked: 998
  • Likes Given: 725
Re: 2018 sea ice area and extent data
« Reply #2162 on: November 22, 2018, 04:45:05 AM »
[ADS-NIPR (JAXA)] ASI Extent.

November 21st, 2018:
     10,131,710 km2, an increase of 158,916 km2:o
     2018 is now the 13th lowest on record.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

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

oren

  • Moderator
  • First-year ice
  • Posts: 6292
    • View Profile
  • Liked: 2311
  • Likes Given: 1947
Re: 2018 sea ice area and extent data
« Reply #2163 on: November 22, 2018, 10:07:22 AM »
I think relentless is the proper word here...

gerontocrat

  • First-year ice
  • Posts: 9315
    • View Profile
  • Liked: 3719
  • Likes Given: 28
Re: 2018 sea ice area and extent data
« Reply #2164 on: November 22, 2018, 11:09:47 AM »
JAXA ARCTIC EXTENT 10,131,710 km2(November 21, 2018)

- Extent increase at 159 k is 85 k above the average (2008-2017) on this day,
- Extent is 13th lowest in the satellite record, see Juan's post above for details (and attached table).
- Freezing to date from minimum is 392 k (7.4%) GREATER than the 10 year average extent gain,
- On average (last 10 years) 53.0 % of the increase in extent from min to max is done.

An extra line in the table based on average extent increase in the last 5 years has been added. This is because extent gain in 2012-13 was so large (rebound from record low minimum) that it distorts the average. The outcome from using the 10 year average extent gain from now is a maximum of 14.72 million km2 (840k > 2017).  Using the previous 5 years's average extent gain, the resulting maximum is 14.62 million km2, (740k > 2017).

Extent gain from minimum now well above average. One did not expect to be able to say that extent on this day is greater than that of 15 years ago.

The late and very slow refreeze in late September early October is now just a memory.
Is this event a demonstration that after a BOE one might expect a similar result?

On average (last 10 years) just half of extent gain from min to max is now done with 111 days to maximum. So who is brave enough given the current state of Arctic Sea Ice to predict the final outcome, given a period of extremely low freezing followed by the reverse?

GFS indicates that overall the Arctic is at a temperature anomaly of around +2 celsius  for the next few days.
______________________________________________________________________
ps: *The 2010's average figure I use in the attached table excludes 2018. I exclude 2018 (from all JAXA and NSIDC tables and graphs) so that the difference of the current year with the 2010's decade to date average is not modified by the current year data.
______________________________________________________________________
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

binntho

  • Nilas ice
  • Posts: 1519
    • View Profile
  • Liked: 528
  • Likes Given: 118
Re: 2018 sea ice area and extent data
« Reply #2165 on: November 22, 2018, 11:12:14 AM »
The diligent and industrious poster gerantocrat called for an intrepid forecaster to make predictions for the evolution of ice extent this winter. I'll go out on a limb and make two falsifiable predictions, and if proven wrong I'll apologize most humbly.

Prediction one: Refreeze in Hudson Bay will stall before reaching 100%.

Prediction two: The maximum this winter will be even lower than last year's.

Both predictions are based on random browsing around in various long-time forecasts on the web and a pet theory of mine that I'll keep quiet about for now.
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

gerontocrat

  • First-year ice
  • Posts: 9315
    • View Profile
  • Liked: 3719
  • Likes Given: 28
Re: 2018 sea ice area and extent data
« Reply #2166 on: November 22, 2018, 11:28:49 AM »
"You're a braver man than me, Gunga Din".
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

oren

  • Moderator
  • First-year ice
  • Posts: 6292
    • View Profile
  • Liked: 2311
  • Likes Given: 1947
Re: 2018 sea ice area and extent data
« Reply #2167 on: November 22, 2018, 11:39:54 AM »
I will not make a prediction but provide a fact: extent maximum is set in 5 seas only: Baffin, Barents, Bering, Okhotsk, and the Greenland Sea. That means that most of the information is still not there yet, and anything is possible. Bering and Barents are the ones mostly affected by climate change and ocean encroachment, so it makes sense they will have low maxima, but the result is highly dependent on prevailing winds in both regions.

Altai

  • New ice
  • Posts: 10
    • View Profile
  • Liked: 6
  • Likes Given: 12
Re: 2018 sea ice area and extent data
« Reply #2168 on: November 22, 2018, 12:25:21 PM »
Probably it will seem stupid, but does anyone admit simply cooler than in the last 10 years air and water conditions in the Arctic this November? Could it be the main precondition of the rapid refreeze?

Neven

  • Administrator
  • First-year ice
  • Posts: 7756
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 1133
  • Likes Given: 521
Re: 2018 sea ice area and extent data
« Reply #2169 on: November 22, 2018, 12:59:14 PM »
Probably it will seem stupid, but does anyone admit simply cooler than in the last 10 years air and water conditions in the Arctic this November? Could it be the main precondition of the rapid refreeze?

The month isn't over yet. We first have to see NCEP Reanalysis data.
Il faut comparer, comparer, comparer, et cultiver notre jardin

oren

  • Moderator
  • First-year ice
  • Posts: 6292
    • View Profile
  • Liked: 2311
  • Likes Given: 1947
Re: 2018 sea ice area and extent data
« Reply #2170 on: November 22, 2018, 01:16:36 PM »
Altai - first of all, welcome. I believe the DMI >80N temp chart supports your point. Not sure about last ten years, but yes it has been consistently cold (relatively only) and quite calm with no winds from the south.

Alison

  • New ice
  • Posts: 56
    • View Profile
  • Liked: 24
  • Likes Given: 145
Re: 2018 sea ice area and extent data
« Reply #2171 on: November 22, 2018, 02:22:30 PM »
Does warm water tend to freeze faster than cold in the right conditions?

Klondike Kat

  • Grease ice
  • Posts: 842
    • View Profile
  • Liked: 46
  • Likes Given: 56
Re: 2018 sea ice area and extent data
« Reply #2172 on: November 22, 2018, 02:43:00 PM »
Does warm water tend to freeze faster than cold in the right conditions?

No.  Spraying hot water into cold air will result in instant freezing due to a combination of severely cold and dry air.  The heat loss due to evaporation will make a difference.  Not so in a water medium.

Altai

  • New ice
  • Posts: 10
    • View Profile
  • Liked: 6
  • Likes Given: 12
Re: 2018 sea ice area and extent data
« Reply #2173 on: November 22, 2018, 02:46:21 PM »
Thank you. I am reading your forum for at least half a year. The day starts from the new data from Juan and finishes with the information from Gerontocrat.

Klondike Kat

  • Grease ice
  • Posts: 842
    • View Profile
  • Liked: 46
  • Likes Given: 56
Re: 2018 sea ice area and extent data
« Reply #2174 on: November 22, 2018, 03:12:05 PM »
The diligent and industrious poster gerantocrat called for an intrepid forecaster to make predictions for the evolution of ice extent this winter. I'll go out on a limb and make two falsifiable predictions, and if proven wrong I'll apologize most humbly.

Prediction one: Refreeze in Hudson Bay will stall before reaching 100%.

Prediction two: The maximum this winter will be even lower than last year's.

Both predictions are based on random browsing around in various long-time forecasts on the web and a pet theory of mine that I'll keep quiet about for now.

I like your courage.  Since you took the lead, I will follow.  This year’s maximum will not only exceed last year’s, but at least 4 of the last 10.  I think Hudson will freeze over completely, due to the NA cold.

binntho

  • Nilas ice
  • Posts: 1519
    • View Profile
  • Liked: 528
  • Likes Given: 118
Re: 2018 sea ice area and extent data
« Reply #2175 on: November 22, 2018, 03:46:04 PM »
The diligent and industrious poster gerantocrat called for an intrepid forecaster to make predictions for the evolution of ice extent this winter. I'll go out on a limb and make two falsifiable predictions, and if proven wrong I'll apologize most humbly.

Prediction one: Refreeze in Hudson Bay will stall before reaching 100%.

Prediction two: The maximum this winter will be even lower than last year's.

Both predictions are based on random browsing around in various long-time forecasts on the web and a pet theory of mine that I'll keep quiet about for now.

I like your courage.  Since you took the lead, I will follow.  This year’s maximum will not only exceed last year’s, but at least 4 of the last 10.  I think Hudson will freeze over completely, due to the NA cold.
Just to clarify: I also expect Hudson Bay to freeze over completely, eventually. But i prognose that the currrent near vertical rise will have a hitch in the next week or so, with 100% reached at a "normal" time.
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

Feeltheburn

  • Frazil ice
  • Posts: 201
    • View Profile
  • Liked: 9
  • Likes Given: 4
Re: 2018 sea ice area and extent data
« Reply #2176 on: November 22, 2018, 04:36:14 PM »
For completeness I note that NSIDC also puts 2018 at 13th place for Nov 21. It had been a couple notches higher than Jaxa. Good to see agreement now. At current pace 2018 will hold 13th position and maybe move up one or two before the end of refreeze. It should finish high this year because of extreme cold and other conditions. Colder than normal winter predicted by NASA report on sunspots.
Feel The Burn!

Phil42

  • New ice
  • Posts: 71
    • View Profile
  • Liked: 88
  • Likes Given: 716
Re: 2018 sea ice area and extent data
« Reply #2177 on: November 22, 2018, 06:56:02 PM »
2018 had 153 days of Arctic Sea Ice Extent below 10'000'000 km2, which is:

 - 8th lowest on record
 - 6 days less than the 2010's (2010-2018) average
 - 9 days less than 2017
 - 19 days less than the record year 2016

bbr2314

  • Nilas ice
  • Posts: 1817
    • View Profile
  • Liked: 163
  • Likes Given: 53
Re: 2018 sea ice area and extent data
« Reply #2178 on: November 22, 2018, 07:02:04 PM »
The diligent and industrious poster gerantocrat called for an intrepid forecaster to make predictions for the evolution of ice extent this winter. I'll go out on a limb and make two falsifiable predictions, and if proven wrong I'll apologize most humbly.

Prediction one: Refreeze in Hudson Bay will stall before reaching 100%.

Prediction two: The maximum this winter will be even lower than last year's.

Both predictions are based on random browsing around in various long-time forecasts on the web and a pet theory of mine that I'll keep quiet about for now.

I like your courage.  Since you took the lead, I will follow.  This year’s maximum will not only exceed last year’s, but at least 4 of the last 10.  I think Hudson will freeze over completely, due to the NA cold.
That prediction is literally what happens every year re: HB as the last vestiges of James Bay freeze up. Way to go, binntho, after attacking me relentlessly, you have made the most milquetoast prediction possible! ::)

gerontocrat

  • First-year ice
  • Posts: 9315
    • View Profile
  • Liked: 3719
  • Likes Given: 28
Re: 2018 sea ice area and extent data
« Reply #2179 on: November 22, 2018, 07:06:07 PM »
I think Hudson will freeze over completely, due to the NA cold.
Just to clarify: I also expect Hudson Bay to freeze over completely, eventually. But i prognose that the currrent near vertical rise will have a hitch in the next week or so, with 100% reached at a "normal" time.
Hudson Bay always freezes over completely. They don't call that part of Canada "The Barrens" for nothing (+ shallow sea with low salinity).
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

  • First-year ice
  • Posts: 9315
    • View Profile
  • Liked: 3719
  • Likes Given: 28
Re: 2018 sea ice area and extent data
« Reply #2180 on: November 22, 2018, 07:13:36 PM »
NSIDC Total Area as at 21 November (5 day trailing average) =  8,801,628 km2
Total Area         
 8,801,628    km2      
 358,230    km2   >   the 2010's average.
 518,966    k   >   2017
         
Total Gain    72    k   
Peripheral Seas   -1    k   loss
Central Seas__    25    k   gain
Other Seas___    48    k   gain
         
Peripheral Seas
Bering _______   -1    k   loss
Baffin  Bay____   -5    k   loss
Greenland____   -0    k   loss
Barents ______    5    k   gain
         
CAB Seas         
Beaufort_____   -8    k   loss
CAA_________   -2    k   loss
East Siberian__    7    k   gain
Central Arctic_    6    k   gain
         
Kara_________    14    k   gain
Laptev_______    1    k   gain
Chukchi______    7    k   gain
         
Other Seas          
Okhotsk______   -1    k   loss
St Lawrence___   -0    k   loss
Hudson Bay___    49    k   gain
Area gain much lower than recently - not a clue why, as no dramatic changes in weather.
Other stuff
GFS says Arctic temperature anomaly at around +2 and staying there for a few days. GFS also saying warmer air is moving West to East across N. America greatly reducing extreme cold in Central and NE Canada by early next week. Stormy weather and relative warmth also moving up Baffin Bay and towards NE Greenland.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

jdallen

  • Young ice
  • Posts: 3244
    • View Profile
  • Liked: 520
  • Likes Given: 205
Re: 2018 sea ice area and extent data
« Reply #2181 on: November 22, 2018, 09:10:27 PM »
Sorry to interrupt the discussion - could someone PM me the location of the NSIDC sea ice area data , both current and archive?

For the life of me, I can't seem to locate it.  Volume and extent I can find, but not area...  at least not summarized.
This space for Rent.

magnamentis

  • Guest
Re: 2018 sea ice area and extent data
« Reply #2182 on: November 22, 2018, 09:12:51 PM »
I think Hudson will freeze over completely, due to the NA cold.
Just to clarify: I also expect Hudson Bay to freeze over completely, eventually. But i prognose that the currrent near vertical rise will have a hitch in the next week or so, with 100% reached at a "normal" time.
Hudson Bay always freezes over completely. They don't call that part of Canada "The Barrens" for nothing (+ shallow sea with low salinity).

what you say + the below avg. temps will turn into above avg. temps within a few days and not only locally which adds to the probability that what you predict will happen exactly as you say.

oren

  • Moderator
  • First-year ice
  • Posts: 6292
    • View Profile
  • Liked: 2311
  • Likes Given: 1947
Re: 2018 sea ice area and extent data
« Reply #2183 on: November 22, 2018, 11:10:26 PM »
jdallen in the same NSIDC ftp folder as all the rest of the files there is a file (the largest file) that breaks down daily area and extent by regions. You need to sum area back up and add the varying size of the pole hole. Hope this helps, I am away from my bookmarks atm.

Juan C. García

  • Nilas ice
  • Posts: 2068
    • View Profile
  • Liked: 998
  • Likes Given: 725
Re: 2018 sea ice area and extent data
« Reply #2184 on: November 23, 2018, 04:48:00 AM »
[ADS-NIPR (JAXA)] ASI Extent.

November 22nd, 2018:
     10,272,807 km2, an increase of 141,097 km2.
     2018 is the 13th lowest on record.
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

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

binntho

  • Nilas ice
  • Posts: 1519
    • View Profile
  • Liked: 528
  • Likes Given: 118
Re: 2018 sea ice area and extent data
« Reply #2185 on: November 23, 2018, 07:33:34 AM »
That prediction is literally what happens every year re: HB as the last vestiges of James Bay freeze up. Way to go, binntho, after attacking me relentlessly, you have made the most milquetoast prediction possible! ::)
What do you mean with "after" ...
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

gerontocrat

  • First-year ice
  • Posts: 9315
    • View Profile
  • Liked: 3719
  • Likes Given: 28
Re: 2018 sea ice area and extent data
« Reply #2186 on: November 23, 2018, 09:49:27 AM »
Sorry to interrupt the discussion - could someone PM me the location of the NSIDC sea ice area data , both current and archive?

For the life of me, I can't seem to locate it.  Volume and extent I can find, but not area...  at least not summarized.

GoTo     https://nsidc.org/arcticseaicenews/sea-ice-tools/ where you can download excel files.
See attached screenshot.

Spreadsheet no. 6 has the area and extent data by region. To get total area you have to add up all 14 seas. (At times like this I wish Lotus 1-2-3 had won and excel had lost). You also have to adjust the Central Arctic Sea extent and area data for the pole hole.
Read on......

https://nsidc.org/the-drift/data-update/sea-ice-index-updated-with-a-new-arctic-pole-hole-and-residual-weather-masks/
Quote
Sea Ice Index Updated with a New Arctic Pole Hole and Ice Masks
MARCH 16, 2015
The NOAA at NSIDC program is pleased to announce that the Sea Ice Index data set has been updated with a reduced Arctic pole hole and improved Northern Hemisphere masks for removing spurious ice caused by residual weather effects.

Beginning 01 January 2008, the data will include a pole hole that covers 0.029 million sq km rather than the previous pole hole of 1.19 million square kilometers. In addition, an error in the pole hole used for data from 01 July 1987 to 31 December 2007 was corrected. These data now uses a pole hole of 0.31 million sq km rather than 1.19 million sq km. The varying pole hole sizes correspond to the orbit inclination of the satellite used to collect the input data.

The new masks are derived from the National Ice Center ice chart monthly climatologies which define more realistic boundaries for ice presence based on recent trends. These new masks have been applied to all historical data. Lastly, the extent values in the daily extent .csv file have been rounded to three decimal places instead of six because anything further than three digits is outside the precision of these data. More information can be found on the Sea Ice Index documentation Web page.

Data Set DOI: http://dx.doi.org/10.7265/N5QJ7F7W

Enjoy
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

  • First-year ice
  • Posts: 9315
    • View Profile
  • Liked: 3719
  • Likes Given: 28
Re: 2018 sea ice area and extent data
« Reply #2187 on: November 23, 2018, 10:04:01 AM »
JAXA ARCTIC EXTENT 10,272,807 km2(November 22, 2018)

- Extent increase at 141 k is 62 k above the average (2008-2017) on this day,
- Extent is 13th lowest in the satellite record, see Juan's post above for details (and attached table).
- Freezing to date from minimum is 454 k (8.5%) GREATER than the 10 year average extent gain,
- On average (last 10 years) 53.8 % of the increase in extent from min to max is done.

An extra line in the table based on average extent increase in the last 5 years has been added. This is because extent gain in 2012-13 was so large (rebound from record low minimum) that it distorts the average. The outcome from using the 10 year average extent gain from now is a maximum of 14.79 million km2 (910k > 2017).  Using the previous 5 years's average extent gain, the resulting maximum is 14.68 million km2, (800k > 2017).

Extent gain from minimum now well above average. One did not expect to be able to say that extent on this day is greater than that of 15 years ago.

The late and very slow refreeze in late September early October is now just a memory.
Is this event a demonstration that after a BOE one might expect a similar result?

On average (last 10 years) just half of extent gain from min to max is now done with 110 days to maximum. So who is brave enough given the current state of Arctic Sea Ice to predict the final outcome, given a period of extremely low freezing followed by the reverse?

GFS indicates that overall the Arctic is at a lower temperature anomaly of around +1 celsius  for the next few days. The extreme cold in northern Canada will moderate.
______________________________________________________________________
ps: *The 2010's average figure I use in the attached table excludes 2018. I exclude 2018 (from all JAXA and NSIDC tables and graphs) so that the difference of the current year with the 2010's decade to date average is not modified by the current year data.
______________________________________________________________________
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

  • First-year ice
  • Posts: 9315
    • View Profile
  • Liked: 3719
  • Likes Given: 28
Re: 2018 sea ice area and extent data
« Reply #2188 on: November 23, 2018, 02:11:15 PM »
NSIDC Total Area as at 22 November (5 day trailing average) =  8,880,289 km2
Total Area         
 8,880,289    km2      
 371,643    km2   >   the 2010's average.
 527,457    k   >   2017
         
Total Gain____    79    k   
Peripheral Seas    7    k   gain
Central Seas__    28    k   gain
Other Seas___    45    k   gain
         
Peripheral Seas         
Bering _______   -1    k   loss
Baffin  Bay____    1    k   gain
Greenland____   -1    k   loss
Barents ______    6    k   gain
         
CAB Seas         
Beaufort_____   -6    k   loss
CAA_________   -2    k   loss
East Siberian__    5    k   gain
Central Arctic_    5    k   gain
         
Kara_________    19    k   gain
Laptev_______    2    k   gain
Chukchi______    6    k   gain
         
Other Seas           
Okhotsk______   -2    k   loss
St Lawrence___   -0    k   loss
Hudson Bay___    46    k   gain
Area gain much lower than recently - not a clue why, as no dramatic changes in weather.
Other stuff
GFS says Arctic temperature anomaly at around +1 and staying there for a few days. GFS also saying warmer air is moving West to East across N. America greatly reducing extreme cold in Central and NE Canada by early next week. Stormy weather and relative warmth also moving up Baffin Bay and towards NE Greenland.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

  • First-year ice
  • Posts: 9315
    • View Profile
  • Liked: 3719
  • Likes Given: 28
Re: 2018 sea ice area and extent data
« Reply #2189 on: November 23, 2018, 02:35:41 PM »
Hudson Area and Extent graphs attached.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

echoughton

  • Frazil ice
  • Posts: 106
    • View Profile
  • Liked: 19
  • Likes Given: 65
Re: 2018 sea ice area and extent data
« Reply #2190 on: November 23, 2018, 04:12:05 PM »
Excuse me if you consider this cherry-picking, but the extent and area growth of late seems to me extraordinary and insane especially during this out-of-control climate change we keep hearing about.  8) 8) 8) 8) 8) 8) 8) 8)

Feeltheburn

  • Frazil ice
  • Posts: 201
    • View Profile
  • Liked: 9
  • Likes Given: 4
Re: 2018 sea ice area and extent data
« Reply #2191 on: November 23, 2018, 05:01:48 PM »
14th place in extent according to NSIDC. Now past all of the following:

2003
2005
2006
2007
2009
2010
2011
2012
2013
2014
2015
2016
2017

Closing gap with 2008 and 2004. No slowdown yet. Perhaps because Hodson didn’t freeze out yet we still have places that must keep freezing.
Feel The Burn!

Shared Humanity

  • Guest
Re: 2018 sea ice area and extent data
« Reply #2192 on: November 23, 2018, 05:22:03 PM »
Excuse me if you consider this cherry-picking, but the extent and area growth of late seems to me extraordinary and insane especially during this out-of-control climate change we keep hearing about.  8) 8) 8) 8) 8) 8) 8) 8)

Ahhhh...yes. Weather gets cold, water freezes and snow falls.

Brigantine

  • Frazil ice
  • Posts: 129
    • View Profile
  • Liked: 27
  • Likes Given: 141
Re: 2018 sea ice area and extent data
« Reply #2193 on: November 23, 2018, 08:26:59 PM »
Excuse me if you consider this cherry-picking, but the extent and area growth of late seems to me extraordinary and insane especially during this out-of-control climate change we keep hearing about.  8) 8) 8) 8) 8) 8) 8) 8)

I imagine the the 1980's average to be an average of essentially 10 differently timed steep rises. The effect of averaging then takes all the steepness out of it.

On this date, maybe 5 years in the 1980's were mostly done already and thus growing slowly again, 1 was rising steeply like 2018, and 4 had not picked up the pace yet and were still low.

It would be interesting to see a plot of extent vs growth rate, with time omitted. Then we could see if the growth rate is unusual at this stage of the S curve.

Regardless of the growth rate, it's fair to interpret that the freeze is happening extraordinary early relative to the last 20 years.

Alexander555

  • Nilas ice
  • Posts: 1259
    • View Profile
  • Liked: 133
  • Likes Given: 44
Re: 2018 sea ice area and extent data
« Reply #2194 on: November 23, 2018, 08:43:31 PM »
Climate change in full action. A chain of extreme events. Warmer oceans, extreme snowfall, high levels of meltwater, stronger storms, heat records, cold records, extreme floods, extreme droughts....... I'm curious how much snow we will get this winter.

magnamentis

  • Guest
Re: 2018 sea ice area and extent data
« Reply #2195 on: November 23, 2018, 08:56:45 PM »
Excuse me if you consider this cherry-picking, but the extent and area growth of late seems to me extraordinary and insane especially during this out-of-control climate change we keep hearing about.  8) 8) 8) 8) 8) 8) 8) 8)

if you'd read a bit before jumping to the obvious in biased terms you would know that:

the less ice there is in summer and considering that the arctic as a whole will freeze over for some time to come in winter, the steeper that curve will be at given times during refreeze. once the peripherals won't freeze like before, the differences between the years will be smaller because the inner arctic will mostly freeze for quite some time to come as mentioned above.

last but not least there will be some kind of change between the years, one year a given region will be cooler and another wamer than previous and/or other years and there will always be people who do exactly that, they cherry pick and say whow.

IMO we could even see a slight slow down in refreeze in hudson because as per now temps turn into positive anomaly. it depends a bit on the real temps because it was and is so cold now that it could still refreeze normally following the quick-freeze of the last few days with extra extreme cold anomalies that served as a kick-starter for that region.

however all that is, we still see regions that are open water that were frozen even during some summers in the past, cherry-picking those will draw another picture as you are certainly aware.

last but not least a doubt clean motives from your side what else would be the reason to post that way. your words can be translated into clear speech and what they mean is not nice.

Dharma Rupa

  • Frazil ice
  • Posts: 493
    • View Profile
  • Liked: 52
  • Likes Given: 26
Re: 2018 sea ice area and extent data
« Reply #2196 on: November 23, 2018, 10:10:24 PM »
the less ice there is in summer and considering that the arctic as a whole will freeze over for some time to come in winter, the steeper that curve will be at given times during refreeze. once the peripherals won't freeze like before, the differences between the years will be smaller because the inner arctic will mostly freeze for quite some time to come as mentioned above.

That may or may not become true.  I'm still of the opinion that when the switch happens it will be sudden and complete, and will not respect time of year.  What I don't see as predictable is when it will happen.

bbr2314

  • Nilas ice
  • Posts: 1817
    • View Profile
  • Liked: 163
  • Likes Given: 53
Re: 2018 sea ice area and extent data
« Reply #2197 on: November 24, 2018, 01:21:04 AM »
Excuse me if you consider this cherry-picking, but the extent and area growth of late seems to me extraordinary and insane especially during this out-of-control climate change we keep hearing about.  8) 8) 8) 8) 8) 8) 8) 8)

if you'd read a bit before jumping to the obvious in biased terms you would know that:

the less ice there is in summer and considering that the arctic as a whole will freeze over for some time to come in winter, the steeper that curve will be at given times during refreeze. once the peripherals won't freeze like before, the differences between the years will be smaller because the inner arctic will mostly freeze for quite some time to come as mentioned above.

last but not least there will be some kind of change between the years, one year a given region will be cooler and another wamer than previous and/or other years and there will always be people who do exactly that, they cherry pick and say whow.

IMO we could even see a slight slow down in refreeze in hudson because as per now temps turn into positive anomaly. it depends a bit on the real temps because it was and is so cold now that it could still refreeze normally following the quick-freeze of the last few days with extra extreme cold anomalies that served as a kick-starter for that region.

however all that is, we still see regions that are open water that were frozen even during some summers in the past, cherry-picking those will draw another picture as you are certainly aware.

last but not least a doubt clean motives from your side what else would be the reason to post that way. your words can be translated into clear speech and what they mean is not nice.

It isn't slowing down yet... the difference a week makes! (although I agree with your rebuke of quoted poster, this is just re: HB)





As I have repeated ad nauseum, the GFS does not incorporate dynamic ice into its forecast (i.e., 00z hr ice extent is 384 hr ice extent, which as you can imagine is very problematic in spring and fall, in particular). It may get a bit warmer over Hudson Bay in the coming days but at this point, even reds (anomaly-wise) are still below 0C. I think this is just bad model output because as NATICE and satellite imagery confirms, the ice is racing towards James Bay, which may hold out for another week or two as a limited area of open water, but I would say we are already at 75% coverage (FINALLY -- still super early), with 90-95% coverage likely within another two or three days.

We shall see!

oren

  • Moderator
  • First-year ice
  • Posts: 6292
    • View Profile
  • Liked: 2311
  • Likes Given: 1947
Re: 2018 sea ice area and extent data
« Reply #2198 on: November 24, 2018, 01:36:34 AM »
Bbr, it's better to use more accurate terms. Coverage - you mean extent, while many others may mean area. Super early - by how much? Compared to what? I think it's one week early compared to most other recent years, well within common variability. Many people will not call that super-early.

bbr2314

  • Nilas ice
  • Posts: 1817
    • View Profile
  • Liked: 163
  • Likes Given: 53
Re: 2018 sea ice area and extent data
« Reply #2199 on: November 24, 2018, 01:38:12 AM »
Bbr, it's better to use more accurate terms. Coverage - you mean extent, while many others may mean area. Super early - by how much? Compared to what? I think it's one week early compared to most other recent years, well within common variability. Many people will not call that super-early.
I think it is earlier than that...

The Canuck charts show earliest since 1993 and I would imagine discrepancy vs recent yrs will worsen further with 11/26 update: