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Rich

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Re: 2019 sea ice area and extent data
« Reply #850 on: May 27, 2019, 11:51:51 AM »
Question for gerontocrat and Juan.

Are you guys open to making and tweaks to the data you present?

One of the things that comes to mind potentially is showing data rounded to the nearest thousand km (000) instead of to the nearest km.

It might make it easier on the eye and generate more interest in the data. The numbers to the right of the last comma probably aren't all that useful.

kassy

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Re: 2019 sea ice area and extent data
« Reply #851 on: May 27, 2019, 01:27:33 PM »
We have regular graphs for easy access or the place of current vs historic years.

I don´t want an extra layer so i have to check if the actual number is rounded up or down if that would be interesting.
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Re: 2019 sea ice area and extent data
« Reply #852 on: May 27, 2019, 01:32:11 PM »
There are posters here who have been here for years and have developed ways to present data that help inform the entire community. Instead of asking for different data, use the data to track conditions and develop insights or questions related to processes.

Human Habitat Index

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Re: 2019 sea ice area and extent data
« Reply #853 on: May 27, 2019, 01:39:05 PM »
The extent declines have been slow because all the easy ice on the Pacific side was gone very early and because the ice margins have large areas of dispersed ice.

If the weather in June and July is like 2017 expect a similar outcome. Most of the melting season is ahead of us. We know the ice is in trouble on a decadal scale, but we cannot predict reliably what July's weather will be.

So the climate may be determined by the weather  ;D
There is a principle which is a bar against all information, which cannot fail to keep a man in everlasting ignorance. That principle is contempt prior to investigation. - Herbert Spencer

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #854 on: May 27, 2019, 02:33:45 PM »
Question for gerontocrat and Juan.

Are you guys open to making and tweaks to the data you present?

The graphs are meant to overcome the difficulty in extracting meaningful information from data tables. Rounding is attractive to some, and annoys others, and my ancient laptop (and my ancient self) is already struggling to cope with spreadsheets with the amount of data and complexity of some of the logic formulae.

e.g. I expect a shambles in 2020 as my spreadsheets are designed to ignore February 29th.
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"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

b_lumenkraft

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Re: 2019 sea ice area and extent data
« Reply #855 on: May 27, 2019, 02:37:55 PM »
The graphs are meant to overcome the difficulty in extracting meaningful information from data tables.

They do exactly that IMHO!

And you are totally right with assuming rounding would annoy some. I'm one of them.

Sorry, Rich.  :P

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #856 on: May 27, 2019, 02:43:21 PM »
NSIDC Total Area as at 26 May 2019 (5 day trailing average) 10,019,210 km2
               
Total Area         
 10,019,210    km2      
-372,985    km2   <   2010's average.
-301,636    k   <   2018
-773,118    k   <   2000's average.
         
Total Area Change   -62    k   loss
Peripheral Seas   -6    k   loss
Central Seas__   -38    k   loss
Other Seas___   -18    k   loss
         
Peripheral Seas         
Bering _______   -0    k   loss
Baffin  Bay____   -5    k   loss
Greenland____   -0    k   loss
Barents ______   -1    k   loss
         
CAB Seas         
Beaufort_____   -11    k   loss
CAA_________    0    k   gain
East Siberian__   -4    k   loss
Central Arctic_   -7    k   loss
         
Kara_________   -6    k   loss
Laptev_______   -9    k   loss
Chukchi______   -2    k   loss
         
Other Seas         
Okhotsk______   -3    k   loss
St Lawrence___   -2    k   loss
Hudson Bay___   -13    k   loss

Area loss 62 k, 2 k less than the 2010's average loss of 64 k on this day.
Total area still 2nd lowest (339 k > 2016)

Temperatures etc
GFS shows temperature anomalies varying from +2.2 to +3.1 celsius over the forecast period, with warmth over most of the Arctic.

At the moment still little reason to suppose sea ice extent loss will accelerate to above average in the immediate future. There were signs of increased above average AREA loss in the central seas but that is fading. However, it does look to me as if the chances of the North-West Passage being fully open are higher this year.

Perhaps the persistent though not extreme warmth in the central arctic will do the ice a mischief. Or is it a question of sun versus cloud and mist, winds, currents and SSTs?

Déjà vu ? At or below average extent loss while over on the melting season thread there were multiple posts of imminent doom in just a few days from now. We will see.
"Para a Causa do Povo a Luta Continua!"
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magnamentis

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Re: 2019 sea ice area and extent data
« Reply #857 on: May 27, 2019, 05:30:35 PM »
Question for gerontocrat and Juan.

Are you guys open to making and tweaks to the data you present?

The graphs are meant to overcome the difficulty in extracting meaningful information from data tables. Rounding is attractive to some, and annoys others, and my ancient laptop (and my ancient self) is already struggling to cope with spreadsheets with the amount of data and complexity of some of the logic formulae.

e.g. I expect a shambles in 2020 as my spreadsheets are designed to ignore February 29th.

in case you're using excel, this could help to make things easier, if not just discard ;)

Excel Round To Quarter Numbers

=IF((Cell or Formula)-INT(Cell or Formula)>0.25,CEILING((Cell or Formula),0.5),FLOOR((Cell or Formula),0.5))

=IF((Cell or Formula)-INT(Cell or Formula)>0.125,CEILING((Cell or Formula),0.25),FLOOR((Cell or Formula),0.25))

of course the formula can be adapted to other target values instead of quarters, i can do that for you should you ever need such a thing.

using the opportunity to thank you for what you provide, i personally don't care whether numbers are rounded or not in that case but see how some prefer shorter numbers that are easier to distinguish at the cost of precsison.

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Re: 2019 sea ice area and extent data
« Reply #858 on: May 27, 2019, 11:39:07 PM »

I don't care about the rounding issue one way or the other I just really appreciate the data thanks.My chemistry professor once told me... I forget exactly how he phrased it but the gist is it doesn't matter what you are measuring four significant figures is hard but five is nearly impossible. I keep the numbers through the calculations but then drop all but the significant figures when reporting the result. Keeping all of the numbers implies unwarranted precision. I believe this applies to measurements in general not just chemistry but I could be wrong.

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #859 on: May 28, 2019, 05:59:02 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

May 27th, 2019:
     11,012,077 km2, a drop of -51,785 km2.
     2019 is 2nd lowest on record.
     (2012 highlighted).
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.

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #860 on: May 28, 2019, 06:04:26 AM »
Question for gerontocrat and Juan.

Are you guys open to making and tweaks to the data you present?

One of the things that comes to mind potentially is showing data rounded to the nearest thousand km (000) instead of to the nearest km.

It might make it easier on the eye and generate more interest in the data. The numbers to the right of the last comma probably aren't all that useful.
I haven't made a macro for the table.
In a way, it has been easy to do the same steps, day by day.
I will think about it, but for the moment, I don’t want to complicate the procedure.

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.

Ktb

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Re: 2019 sea ice area and extent data
« Reply #861 on: May 28, 2019, 06:08:15 AM »
JCG, your updates make my updates easier! Please do not change!
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #862 on: May 28, 2019, 09:04:14 AM »
JAXA ARCTIC EXTENT :- 11,012,077 km2(May 27, 2019)

- Extent is 2nd lowest in the satellite record, 381 k > 2016, 36 k < 2018.
- Extent loss on this day 52 k, 7 k more than the average loss of 45 k on this day.
- Extent loss from maximum 3,259 k, 367 k (13%) greater than the average of 2,892k loss from maximum by this day,
- On average 29.3% of the melting season done, with 109 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 4.02 million km2, 3rd lowest in the satellite record, and 0.84 million km2 above the 2012 low of 3.18 million km2.

On 22nd April, 2016 started its 2 months as the front runner with steep declines in extent.  To become lowest again, 2019 will have to match or exceed the above average extent losses of 2016 from now until at least mid-late June. For that reason I have removed 2018 daily change and replaced it with 2016 data on graph Arc2. Later in the season that will be replaced with 2012 as it becomes the front runner.

Other Stuff

GFS shows temperature anomalies varying from +1.9 to +3.1 celsius over the forecast period, with warmth over most of the Arctic, a little bit cooler every day.

At the moment still little reason to suppose sea ice extent loss will accelerate to much above average in the immediate future. There were signs of increased above average AREA loss in the central seas, and at the moment it does look to me as if the chances of the North-West Passage being fully open are higher this year.

Perhaps the persistent though not extreme warmth in the central arctic will do the ice a mischief. Or is it a question of sun versus cloud and mist, winds, currents and SSTs?

I continue to succumb to a sense of déjà vu, with at or below average extent loss while over on the melting season thread multiple posts of imminent doom in just a few days from now.
We will see.
"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)

Sterks

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Re: 2019 sea ice area and extent data
« Reply #863 on: May 28, 2019, 09:47:32 AM »
Two thoughts:
- Although the anomalies go down, this does not mean the temperatures do especially at this time of the year. Otoh temperatures very high lat (75+N) start to approach the ceiling imposed by ice melting, which will be absorbing the heat.
- The high pressure dome for the first week of June is hardly a deja vu for the last 7 seasons. It may be less or more dangerous, I don't know, but it kind of breaks what I am used to since 2013. We'll see what happens later on.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #864 on: May 28, 2019, 10:46:31 AM »
Two thoughts:
- Although the anomalies go down, this does not mean the temperatures do especially at this time of the year. Otoh temperatures very high lat (75+N) start to approach the ceiling imposed by ice melting, which will be absorbing the heat.
- The high pressure dome for the first week of June is hardly a deja vu for the last 7 seasons. It may be less or more dangerous, I don't know, but it kind of breaks what I am used to since 2013. We'll see what happens later on.
My déjà vu is about the armageddon stuff. OK, this year it is a high pressure dome, last year it was something else. Nor am I saying melting will stop, rather that my guess is that it will not be that much above average for the next week or so.

So, in the sure and certain knowledge that it will be wrong, for now I am sticking with my guess of a September minimum of 4.00 million km2, just 2nd lowest in the satellite record. That is an average of the last 10 years remaining melt. Using the last 5 years average remaining melt gives a figure of more like 4.25 million, 6th lowest in the satellite record.

But - the PIOMAS May data should be out in a week or so. That could change my point of view entirely.

"Para a Causa do Povo a Luta Continua!"
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Gray-Wolf

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Re: 2019 sea ice area and extent data
« Reply #865 on: May 28, 2019, 11:30:59 AM »
As I see it the past 3 or 4 years have ended with a lot of ice that would not stand 3 weeks of further melt?

If we see lots of energy poured into the pack this year we may not see huge drops as there will still be ice left after the energy has shaved off the top surfaces?

It will be Aug before we see what the 'melt momentum' has meant for the rump of the ice as we approach min?

Again the unrepresentative 15% or more will plump up numbers in the central area but our eyes will give us a differing view of just what is left?
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Re: 2019 sea ice area and extent data
« Reply #866 on: May 28, 2019, 11:45:11 AM »
Not sure why Climate Reanalizer has us a few degrees warmer, yet... DMI shows us right on the average line?  Remember in 2016 after Beaufort got well past the NW Passage and then the ice moved back in.
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Re: 2019 sea ice area and extent data
« Reply #867 on: May 28, 2019, 01:39:30 PM »
Not sure why Climate Reanalizer has us a few degrees warmer, yet... DMI shows us right on the average line?  Remember in 2016 after Beaufort got well past the NW Passage and then the ice moved back in.

DMI is 80 ° North, CCI is 66,5° (Arctic Circle) North

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #868 on: May 28, 2019, 02:29:54 PM »
NSIDC Total Area as at 27 May 2019 (5 day trailing average) 9,966,266 km2
               
Total Area         
 9,966,266    km2      
-353,994    km2   <   2010's average.
-290,144    k   <   2018
-763,838    k   <   2000's average.
         
Total Area Change   -53    k   loss
Peripheral Seas   -4    k   loss
Central Seas__   -36    k   loss
Other Seas___   -13    k   loss
         
Peripheral Seas         
Bering _______   -1    k   loss
Baffin  Bay____   -4    k   loss
Greenland____    1    k   gain
Barents ______   -1    k   loss
         
CAB Seas         
Beaufort_____   -7    k   loss
CAA_________   -0    k   loss
East Siberian__   -3    k   loss
Central Arctic_   -5    k   loss
         
Kara_________   -9    k   loss
Laptev_______   -9    k   loss
Chukchi______   -3    k   loss
         
Other Seas         
Okhotsk______   -4    k   loss
St Lawrence___   -1    k   loss
Hudson Bay___   -9    k   loss

Area loss 53 k, 18 k less than the 2010's average loss of 71 k on this day.
Total area still 2nd lowest (351 k > 2016)

Temperatures etc
GFS shows temperature anomalies varying from +1.9 to +3.1 celsius over the forecast period, with warmth over most of the Arctic.

At the moment still little reason to suppose sea ice extent loss will accelerate to above average in the immediate future. There were signs of increased above average AREA loss in the central seas but that has faded.

(Volume data for May available next week).
"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)

Wipneus

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Re: 2019 sea ice area and extent data
« Reply #869 on: May 28, 2019, 03:05:17 PM »
Update of the NSIDC NT sea ice extent and area graphs for the Arctic Basin only (with the understanding that most of the ice to survive the 2019 summer melt will be found there).

Very close to 2016 in the contest for lowest values for the day of year.

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Re: 2019 sea ice area and extent data
« Reply #870 on: May 29, 2019, 12:09:33 AM »
I have revived and updated my NSIDC Compactness graph (based on data provided by Wipneus). Nothing spectacular as of yet:
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Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #871 on: May 29, 2019, 05:41:46 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

May 28th, 2019:
     10,941,402 km2, a drop of -70,675 km2.
     2019 is 2nd lowest on record.
     (2012 highlighted).
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.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #872 on: May 29, 2019, 07:32:04 AM »
JAXA ARCTIC EXTENT :- 10,941,402 km2(May 28, 2019)

First loss significantly above average for some time.
- Extent is 2nd lowest in the satellite record, 364 k > 2016, 77 k < 2018.
- Extent loss on this day 71 k, 31 k more than the average loss of 40 k on this day.
- Extent loss from maximum 3,330 k, 396 k (14%) greater than the average of 2,934k loss from maximum by this day,
- On average 29.7% of the melting season done, with 108 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 3.99 million km2, 2nd lowest in the satellite record, and 0.81 million km2 above the 2012 low of 3.18 million km2.

On 22nd April, 2016 started its 2 months as the front runner with steep declines in extent.  To become lowest again, 2019 will have to match or exceed the above average extent losses of 2016 from now until at least mid-late June. For that reason I have removed 2018 daily change and replaced it with 2016 data on graph Arc2. Later in the season that will be replaced with 2012 as it becomes the front runner.

Other Stuff

GFS shows temperature anomalies varying from +2.2 to +3.2. At the moment still little reason to suppose sea ice extent loss will continue at much above average in the immediate future.
"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

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Re: 2019 sea ice area and extent data
« Reply #873 on: May 29, 2019, 02:11:29 PM »
NSIDC Total Area as at 27 May 2019 (5 day trailing average) 9,907,041 km2
               
Total Area         
 9,907,041    km2      
-344,956    km2   <   2010's average.
-292,011    k   <   2018
-767,978    k   <   2000's average.
         
Total Area Change   -59    k   loss
Peripheral Seas   -10    k   loss
Central Seas__   -37    k   loss
Other Seas___   -13    k   loss
         
Peripheral Seas         
Bering _______   -1    k   loss
Baffin  Bay____   -7    k   loss
Greenland____    1    k   gain
Barents ______   -3    k   loss
         
CAB Seas         
Beaufort_____   -8    k   loss
CAA_________   -1    k   loss
East Siberian__    3    k   gain
Central Arctic_   -6    k   loss
         
Kara_________   -11    k   loss
Laptev_______   -6    k   loss
Chukchi______   -7    k   loss
         
Other Seas         
Okhotsk______   -1    k   loss
St Lawrence___   -0    k   loss
Hudson Bay___   -12    k   loss

Area loss 59 k, 13 k less than the 2010's average loss of 72 k on this day.
Total area still 2nd lowest (340 k > 2016)

Temperatures etc
GFS shows temperature anomalies varying from +2.2 to +3.2 celsius. At the moment still little reason to suppose sea ice extent loss will continue at much above average in the immediate future.

(Volume data for May available next week).
"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

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Re: 2019 sea ice area and extent data
« Reply #874 on: May 29, 2019, 02:47:39 PM »
I have revived and updated my NSIDC Compactness graph (based on data provided by Wipneus). Nothing spectacular as of yet:
So I dragged mine out of hibernation as well. Only 2 things of note immediately appear...

The decline in the compaction ratio decade by decade is very visible,
2016 compaction ended the lowest and persisted through Autumn and early Winter.

I presume that there is a significant correlation between decreased compaction and increased ice-pack mobility, leading to increased export to killing zones.
"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)

b_lumenkraft

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Re: 2019 sea ice area and extent data
« Reply #875 on: May 29, 2019, 03:40:44 PM »
I presume that there is a significant correlation between decreased compaction and increased ice-pack mobility, leading to increased export to killing zones.

Sounds like a no-brainer to me.

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #876 on: May 30, 2019, 05:32:01 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

May 29th, 2019:
     10,879,554 km2, a drop of -61,848 km2.
     2019 is 2nd lowest on record.
     (2012 highlighted).
« Last Edit: May 30, 2019, 06:23:57 AM by Juan C. García »
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.

epiphyte

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Re: 2019 sea ice area and extent data
« Reply #877 on: May 30, 2019, 07:22:58 AM »

I presume that there is a significant correlation between decreased compaction and increased ice-pack mobility, leading to increased export to killing zones.

Indeed. Not just export though - decreased compaction --> open water in the interstices between floes --> decreased overall albedo --> energy absorption by surface liquid water adjacent to ice --> "Im Melting!"


gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #878 on: May 30, 2019, 08:12:17 AM »
JAXA ARCTIC EXTENT :- 10,879,554 km2(May 29, 2019)

- Extent is 2nd lowest in the satellite record, 355 k > 2016, 100 k < 2018.
- Extent loss on this day 62 k, 21 k more than the average loss of 41 k on this day.
- Extent loss from maximum 3,392 k, 417 k (14%) greater than the average of 2,975k loss from maximum by this day,
- On average 30.1% of the melting season done, with 107 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 3.97 million km2, 2nd lowest in the satellite record, and 0.79 million km2 above the 2012 low of 3.18 million km2.

On 22nd April, 2016 started its 2 months as the front runner with steep declines in extent.  To become lowest again, 2019 will have to match or exceed the above average extent losses of 2016 from now until at least mid-late June. For that reason I have removed 2018 daily change and replaced it with 2016 data on graph Arc2. Later in the season that will be replaced with 2012 as it becomes the front runner.

Other Stuff

GFS shows temperature anomalies varying from +1.7 to +2.7. At the moment still little reason to suppose sea ice extent loss will continue at much above average in the immediate future.
"Para a Causa do Povo a Luta Continua!"
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"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #879 on: May 30, 2019, 02:58:16 PM »
NSIDC Total Area as at 29 May 2019 (5 day trailing average) 9,845,201 km2
               
Total Area         
 Total Area         
 9,845,201    km2      
-343,601    km2   <   2010's average.
-289,648    k   <   2018
-774,898    k   <   2000's average.
         
Total Area Change   -62    k   loss
Peripheral Seas   -16    k   loss
Central Seas__   -36    k   loss
Other Seas___   -10    k   loss
         
Peripheral Seas         
Bering _______   -1    k   loss
Baffin  Bay____   -13    k   loss
Greenland____    2    k   gain
Barents ______   -3    k   loss
         
CAB Seas         
Beaufort_____   -8    k   loss
CAA_________   -5    k   loss
East Siberian__    10    k   gain
Central Arctic_   -11    k   loss
         
Kara_________   -10    k   loss
Laptev_______   -2    k   loss
Chukchi______   -11    k   loss
         
Other Seas         
Okhotsk______    1    k   gain
St Lawrence___    0    k   gain
Hudson Bay___   -11    k   loss

Area loss 62 k, 6 k less than the 2010's average loss of 68 k on this day.
Total area still 2nd lowest (331 k > 2016)

Temperatures etc
GFS shows temperature anomalies varying from +1.7 to +2.7 celsius. At the moment still little reason to suppose sea ice extent loss will continue at much above average in the immediate future.

But the chances of the North-West passage being open this year seem to improve all the time.

(Volume data for May available next week).
"Para a Causa do Povo a Luta Continua!"
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"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #880 on: May 30, 2019, 03:09:34 PM »
The seas of the North-West Passage are melting pretty well,
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #881 on: May 30, 2019, 03:11:31 PM »
But it is the CAA that will be the key..
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Re: 2019 sea ice area and extent data
« Reply #882 on: May 30, 2019, 03:16:25 PM »
Area losses very consistent. 14 consecutive days over 50k.

FrostKing70

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Re: 2019 sea ice area and extent data
« Reply #883 on: May 30, 2019, 03:19:14 PM »
Very curious!  I didn't notice before that in 2016 the ice increased in June in the Beaufort.   I assume (there's that word again!) that ice was not created in June in the Arctic, was this movement of ice from elsewhere?

Stephan

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Re: 2019 sea ice area and extent data
« Reply #884 on: May 30, 2019, 07:03:08 PM »
Usually those increases in late spring and summer are a result of import of ice from a neighbouring region. With T higher than -3°C in all and higher than -1°C in many regions of the Arctic Ocean (see https://climatereanalyzer.org/wx/DailySummary/#t2) a refreeze is more than unlikely.

Secondly it may be possible that the evaluation of the satellite data - especially in bays and close to the shoreline - can be misinterpreted. So on one day that area is declared 'ice free' and some days later it counts again as 'ice covered' which suggests an increase of ice area or extent while in reality there has been no change.
« Last Edit: May 30, 2019, 07:16:39 PM by Stephan »
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Re: 2019 sea ice area and extent data
« Reply #885 on: May 31, 2019, 03:33:34 AM »
2016 is about to enter a 2 week span of below average losses, and even a small gain for one day. Perhaps 2019 will cover the gap.
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Re: 2019 sea ice area and extent data
« Reply #886 on: May 31, 2019, 03:42:08 AM »
2016 is about to enter a 2 week span of below average losses, and even a small gain for one day. Perhaps 2019 will cover the gap.
It is just after that in 2016, when most of us managed to recover from our heart attacks and actually watch the numbers again without panicking (more).

$64 question now is will the weather cooperate and repeat itself, or will 2019 continue motoring inexorably downwards past 2016 and below.
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Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #887 on: May 31, 2019, 05:59:43 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

May 30th, 2019:
     10,833,061 km2, a drop of -46,493 km2.
     2019 is 2nd lowest on record.
     (2012 highlighted).
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.

Archimid

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Re: 2019 sea ice area and extent data
« Reply #888 on: May 31, 2019, 06:02:35 AM »
Very curious!  I didn't notice before that in 2016 the ice increased in June in the Beaufort.   I assume (there's that word again!) that ice was not created in June in the Arctic, was this movement of ice from elsewhere?

A nuance. The amount of ice didn’t increase, extent did.
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #889 on: May 31, 2019, 10:44:12 AM »
JAXA ARCTIC EXTENT :- 10,833,061 km2(May 30, 2019)

- Extent is 2nd lowest in the satellite record, 352 k > 2016, 82 k < 2018.
- Extent loss on this day 46 k, 10 k less than the average loss of 56 k on this day.
- Extent loss from maximum 3,438 k, 408 k (13%) greater than the average of 3,030k loss from maximum by this day,
- On average 30.7% of the melting season done, with 106 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 3.98 million km2, 2nd lowest in the satellite record, and 0.80 million km2 above the 2012 low of 3.18 million km2.

On 22nd April, 2016 started its 2 months as the front runner with steep declines in extent.  To become lowest again, 2019 will have to match or exceed the above average extent losses of 2016 from now until at least mid-late June. For that reason I have removed 2018 daily change and replaced it with 2016 data on graph Arc2. Later in the season that will be replaced with 2012 as it becomes the front runner.

Other Stuff

GFS shows temperature anomalies varying from +1.9 to +3.0. At the moment little reason to suppose sea ice extent loss will be at much above average in the immediate future.
"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

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Re: 2019 sea ice area and extent data
« Reply #890 on: May 31, 2019, 02:13:53 PM »
NSIDC Total Area as at 30 May 2019 (5 day trailing average) 9,785,827 km2
               
Total Area         
 9,785,827    km2      
-339,512    km2   <   2010's average.
-273,233    k   <   2018
-775,905    k   <   2000's average.
         
Total Area Change   -59    k   loss
Peripheral Seas   -20    k   loss
Central Seas__   -26    k   loss
Other Seas___   -13    k   loss
         
Peripheral Seas         
Bering _______   -1    k   loss
Baffin  Bay____   -17    k   loss
Greenland____    1    k   gain
Barents ______   -3    k   loss
         
CAB Seas         
Beaufort_____   -7    k   loss
CAA_________   -4    k   loss
East Siberian__    13    k   gain
Central Arctic_   -13    k   loss
         
Kara_________   -10    k   loss
Laptev_______    1    k   gain
Chukchi______   -6    k   loss
         
Other Seas         
Okhotsk______   -1    k   loss
St Lawrence___    1    k   gain
Hudson Bay___   -13    k   loss

Area loss 59 k, 4 k less than the 2010's average loss of 63 k on this day.
Total area still 2nd lowest (334 k > 2016)

Temperatures etc
GFS shows temperature anomalies varying from +1.9 to +3.0. At the moment little reason to suppose sea ice extent loss will be at much above average in the immediate future.
But the chances of the North-West passage being open this year seem to improve all the time.

(Volume data for May available next week).
"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)

Sterks

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Re: 2019 sea ice area and extent data
« Reply #891 on: May 31, 2019, 04:04:16 PM »
Gerontocrat I'm sorry, really, I am not for creating dissension gratuitously, but I would be really surprised if both extent and especially area don't plummet well above average during the first 10 days of the month.

Stephan

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Re: 2019 sea ice area and extent data
« Reply #892 on: May 31, 2019, 04:12:41 PM »
Analysis of the development "relative area wise" between May 15 and May 30:
Loss > 40%: Okhotsk*
Loss 22-29%: Beaufort, Bering*, Baffin, Barents [all seas beginning with "B", funny]
Loss 15%: Kara
Loss 8-9%: St. Lawrence*, Hudson, Chukchi
Loss < 5%: CAA, CAB, Laptev, ESS, Grønland

* The area is very small therefore even small changes result in a high relative loss
___

It looks like Hudson finally starts to melt
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #893 on: May 31, 2019, 04:42:50 PM »
Gerontocrat I'm sorry, really, I am not for creating dissension gratuitously, but I would be really surprised if both extent and especially area don't plummet well above average during the first 10 days of the month.
I would not be surprised either, but I see nothing in the forecasts to make me assume a rapid change in sea ice loss over the next week or two. But then, I am not an expert in ocean currents at various depths, ocean mixing, winds etc etc etc etc.

The data will tell us. Patience is a virtue, they say. (Who are "they"?)
"Para a Causa do Povo a Luta Continua!"
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jdallen

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Re: 2019 sea ice area and extent data
« Reply #894 on: June 01, 2019, 04:57:35 AM »
Gerontocrat I'm sorry, really, I am not for creating dissension gratuitously, but I would be really surprised if both extent and especially area don't plummet well above average during the first 10 days of the month.
I would not be surprised either, ...
I'm not expecting rapid changes in extent and area, but I am expecting some serious preconditioning to take place for losses later in June or July.

Melt ponds, anyone?
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Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #895 on: June 01, 2019, 05:40:42 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

May 31st, 2019:
     10,768,933 km2, a drop of -64,128 km2.
     2019 is 2nd lowest on record.
     (2012 highlighted).
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.

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #896 on: June 01, 2019, 05:47:16 AM »
Gerontocrat I'm sorry, really, I am not for creating dissension gratuitously, but I would be really surprised if both extent and especially area don't plummet well above average during the first 10 days of the month.
...
The data will tell us. Patience is a virtue, they say. (Who are "they"?)
I see the possibility that 2019 will become the lowest on record by June 15th.
As Gerontocrat says: "The data will tell us. Patience is a virtue, they say.".
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.

Pmt111500

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Re: 2019 sea ice area and extent data
« Reply #897 on: June 01, 2019, 06:21:59 AM »
Gerontocrat I'm sorry, really, I am not for creating dissension gratuitously, but I would be really surprised if both extent and especially area don't plummet well above average during the first 10 days of the month.
...
The data will tell us. Patience is a virtue, they say. (Who are "they"?)
I see the possibility that 2019 will become the lowest on record by June 15th.
As Gerontocrat says: "The data will tell us. Patience is a virtue, they say.".
Many years have seen the 2012 like drop (not as steep though) in area during this time of year but so far 2012 is the only year when this has been realized also in extent. This would require a pause in export via Fram and to Barentz, melting the exported ice and intensifying of the melt in Pacific sector.
Cooling the outside by heat pump.

Ktb

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Re: 2019 sea ice area and extent data
« Reply #898 on: June 01, 2019, 07:04:18 AM »
Bimonthly BOE evaluation

May 31 extent was 10,768,933 km^2. With on average 105 days to go until the end of the melt season on September 13th, we now require a daily drop of -93,037 km^2 for a BOE to occur. (See Attachment 1).

Total extent loss thus in May 2019 was -1,536,443 km^2. And total extent loss so far this season is -3,502,188 km^2. This has resulted in the current average daily drop of -43,777 km^2. We have experienced the 2nd fastest rate of daily loss from Maximum to the end of May -- behind 2010 at a whopping -57,318 km^2 per day. Impressively strong early season melt is still holding our average high. (See Attachment 2).

Looking only at the month of May, we have averaged -49,563 km^2 per day. This average daily drop places May 2019 as 8th out of 13 (2007-2019) in average daily May melt (See Attachment 3).

Additionally: Note the significant lack of green in the first attachment at this point. We had 0 days of melt greater than the BOE requirement set on the first of the month (-83,128 km^2). So we fall further and further behind.
« Last Edit: June 01, 2019, 07:16:59 AM by Ktb »
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Ktb

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Re: 2019 sea ice area and extent data
« Reply #899 on: June 01, 2019, 07:11:15 AM »
And for comparisons to other years:

The following attachment is for actual previous years daily average melt from June 1 to their respective minimums (Attachment 1).

The following section is for what the previous years would have needed for a BOE to occur: From June 1st to each years respective minimum, our current BOE requirement is the 3rd highest value, behind only 2016 which required an average daily drop of -86,285 km^2, and 2018 which required an average daily drop of -86,909 km^2. Keep in mind that 2018's minimum was reached on September 21st, and that 2016's minimum was reached on September 7th. (See attachment 2). End

As an aside, for a BOE to occur at this point, we would need to have the strongest June melt for the years 2007-2018 (and likely ever since the satellite record began), an above average July melt, the strongest August melt, and the strongest September 1st to minimum.
I have amazing news for you. Man is not alone on this planet. He is part of a community, upon which he depends absolutely.
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