Support the Arctic Sea Ice Forum and Blog

Author Topic: 2018 sea ice area and extent data  (Read 522531 times)

gerontocrat

  • First-year ice
  • Posts: 6824
    • View Profile
  • Liked: 1727
  • Likes Given: 22
Re: 2018 sea ice area and extent data
« Reply #950 on: July 04, 2018, 03:35:37 PM »
The June 3rd decrease of 53k

Making so many typos myself, I am glad of a chance to correct someone other than myself - JULY 3rd decrease methinks.
"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

  • Young ice
  • Posts: 4537
    • View Profile
  • Liked: 915
  • Likes Given: 1307
Re: 2018 sea ice area and extent data
« Reply #951 on: July 04, 2018, 04:09:53 PM »
I expect July melt to catch up some of the ground (un)lost in June, including some century breaks, due to losses in the periphery.

Pagophilus

  • Frazil ice
  • Posts: 287
    • View Profile
  • Liked: 120
  • Likes Given: 162
Re: 2018 sea ice area and extent data
« Reply #952 on: July 05, 2018, 05:46:15 AM »
I expect July melt to catch up some of the ground (un)lost in June, including some century breaks, due to losses in the periphery.

In support of that, the South Kara Sea ice (below, unaltered image) is looking particularly dark and gray these days, and the Hudson ice seems a similar shade.  So albedo is getting lower, and both are currently receiving a good deal of insolation.

jdallen

  • Young ice
  • Posts: 3024
    • View Profile
  • Liked: 190
  • Likes Given: 172
Re: 2018 sea ice area and extent data
« Reply #953 on: July 05, 2018, 05:53:42 AM »
I expect July melt to catch up some of the ground (un)lost in June, including some century breaks, due to losses in the periphery.

In support of that, the South Kara Sea ice (below, unaltered image) is looking particularly dark and gray these days, and the Hudson ice seems a similar shade.  So albedo is getting lower, and both are currently receiving a good deal of insolation.
Watching ice like that, typically at this stage it's about 7-10 days from disappearing.
This space for Rent.

Juan C. García

  • Nilas ice
  • Posts: 1533
    • View Profile
  • Liked: 547
  • Likes Given: 518
Re: 2018 sea ice area and extent data
« Reply #954 on: July 05, 2018, 06:10:20 AM »
[ADS-NIPR-JAXA] ASI Extent.

It has passed 30+ minutes of the usual time and ADS NIPR has no data.
So, I appreciate if someone else post the data, at least extent and daily drop.
Thanks!

https://ads.nipr.ac.jp/vishop/#/extent
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

  • First-year ice
  • Posts: 6824
    • View Profile
  • Liked: 1727
  • Likes Given: 22
Re: 2018 sea ice area and extent data
« Reply #955 on: July 05, 2018, 07:27:43 AM »
It has passed 30+ minutes of the usual time and ADS NIPR has no data.
So, I appreciate if someone else post the data, at least extent and daily drop.
Thanks!
Glad to oblige, Juan.

JAXA Arctic Sea Ice Extent - 9,079,816 km2(July 4, 2018)

A daily drop of just 56k, well over 30k less than the average for the time of year.
Extent loss to date is 640k km2 (12%) below the 2010's average, with 55% of the average melting season done.
A September minimum of above 4.5 million km2 looks more likely every day.
"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)

Neven

  • Administrator
  • First-year ice
  • *****
  • Posts: 7209
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 732
  • Likes Given: 477
Re: 2018 sea ice area and extent data
« Reply #956 on: July 05, 2018, 02:49:37 PM »
With compactness dropping another 1.5%, 2018 is slowly moving to the lower range of the pack:
Il faut comparer, comparer, comparer, et cultiver notre jardin

gerontocrat

  • First-year ice
  • Posts: 6824
    • View Profile
  • Liked: 1727
  • Likes Given: 22
Re: 2018 sea ice area and extent data
« Reply #957 on: July 05, 2018, 03:23:01 PM »
NSIDC Total Area as at 4 July (5 day trailing average =  7,190,592 km2
This is 334 k above the 2010-2017 average


Total Area loss 161K    
Central Seas loss 121 k Periphery loss 21 k, Other Seas loss 19 k
 

Analysis of individual seas.

Pacific Side
- The Okhotsk Sea area is 6 k (down 2k),
- The Bering Sea area is 2 k,
- Chukchi Sea loss 10 k,
- Beaufort Sea loss 13 k,

Atlantic Side
- Total area loss of the Baffin, Greenland, and Barents Seas 20 k,
of which the Baffin Sea loss was 10 k, the Greenland Sea loss 6k,and  the Barents Sea loss 4 k
- The Kara Sea area loss 10 k.
- The Laptev Sea area loss 24 k  .

CAB
- The Central Arctic Sea loss 45 k
- The Canadian Archipelago gain 2 k
- East Siberian Sea loss 22 k

Other seas
- St Lawrence area at 1 k,
- Hudson Bay area loss 17 k.

NSIDC Area is sitting between the 2010's average and the 2000's average, very much as in JAXA EXTENT.
"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: 1533
    • View Profile
  • Liked: 547
  • Likes Given: 518
Re: 2018 sea ice area and extent data
« Reply #958 on: July 06, 2018, 05:54:50 AM »
It has passed 30+ minutes of the usual time and ADS NIPR has no data.
So, I appreciate if someone else post the data, at least extent and daily drop.
Thanks!
Glad to oblige, Juan.


Thanks, gerontocrat.  :)
_______________________________

[ADS-NIPR-JAXA] ASI Extent.

July 5th, 2018: 9,013,080 km2, a drop of -66,736 km2.
2018 is the tenth 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

  • Young ice
  • Posts: 4537
    • View Profile
  • Liked: 915
  • Likes Given: 1307
Re: 2018 sea ice area and extent data
« Reply #959 on: July 06, 2018, 07:42:16 AM »
A strange season. While JAXA extent is 10th (!), the Inner Basin extent is 1st or 2nd in the 2012-2018 data as shown by Wipneus. Which version of this tale will win?

Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4009
    • View Profile
    • Arctische Pinguin
  • Liked: 644
  • Likes Given: 0
Re: 2018 sea ice area and extent data
« Reply #960 on: July 06, 2018, 08:12:02 AM »
Yes, some regions outside the Basin are slow to melt-out (Hudson, Baffin, Kara). Here is an update of the Basin-only graphs based on NSIDC data.

gerontocrat

  • First-year ice
  • Posts: 6824
    • View Profile
  • Liked: 1727
  • Likes Given: 22
Re: 2018 sea ice area and extent data
« Reply #961 on: July 06, 2018, 09:09:14 AM »
JAXA Arctic Sea Ice Extent - 9,013,080 km2(July 5, 2018)

A daily drop of just 66k, about 30k less than the average for the time of year.
Extent loss to date is 670k km2 (12%) below the 2010's average, with 56% of the average melting season done.
Resulting minimum from average remaining melt = 4.6 million km2, (excluding 2012 from the average 4.7 million km2). Range of results from last ten years is 3.63 to 5.25 million km2.

With, on average, just 44% of further extent loss to go, a September minimum of 4.5 to 5.0 million km2 looks more likely every day.
"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)

RikW

  • Frazil ice
  • Posts: 179
    • View Profile
  • Liked: 19
  • Likes Given: 10
Re: 2018 sea ice area and extent data
« Reply #962 on: July 06, 2018, 09:25:38 AM »
The big question for me is: "Will Hudson Bay and Kara sea completely melt out?"
And on a sidenote, what will the effect be on the next years that they will have had much more ice-cover during peak-insolation compared to previous years

If the 400/450k area/ the 1M extent surplus, compared to record years, still completely melts out, we will still be in/near record-low extent territory.

gerontocrat

  • First-year ice
  • Posts: 6824
    • View Profile
  • Liked: 1727
  • Likes Given: 22
Re: 2018 sea ice area and extent data
« Reply #963 on: July 06, 2018, 10:40:59 AM »
The big question for me is: "Will Hudson Bay and Kara sea completely melt out?"

No reason to suppose Hudson Bay will not melt out completely. Already well over half gone.
Kara Sea will probably almost completely melt out as usual. Also well over half gone.
They are just a bit late this year.
"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)

Frivolousz21

  • Nilas ice
  • Posts: 1507
  • Live in Belleville, IL..15 miles SE of St. Louis.
    • View Profile
  • Liked: 140
  • Likes Given: 2
Re: 2018 sea ice area and extent data
« Reply #964 on: July 06, 2018, 11:54:15 AM »
The atlantc side is skewing the inner basin drops.

The Pacific side has been well protected.

So a slow down is very likely as we go along
I got a nickname for all my guns
a Desert Eagle that I call Big Pun
a two shot that I call Tupac
and a dirty pistol that love to crew hop
my TEC 9 Imma call T-Pain
my 3-8 snub Imma call Lil Wayne
machine gun named Missy so loud
it go e-e-e-e-ow e-e-e-e-e-e-blaow

Cid_Yama

  • Frazil ice
  • Posts: 232
    • View Profile
    • The Post Peak Oil Historian
  • Liked: 26
  • Likes Given: 0
Re: 2018 sea ice area and extent data
« Reply #965 on: July 06, 2018, 02:01:17 PM »
90+% is a foot (30cm) or less in thickness this year.  That's the difference.

In 2012 50+% was >50 cm.
"For my part, whatever anguish of spirit it may cost, I am willing to know the whole truth; to know the worst and provide for it." - Patrick Henry

gerontocrat

  • First-year ice
  • Posts: 6824
    • View Profile
  • Liked: 1727
  • Likes Given: 22
Re: 2018 sea ice area and extent data
« Reply #966 on: July 06, 2018, 02:20:56 PM »
NSIDC June Analysis posted on http://nsidc.org/arcticseaicenews/
"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)

Pagophilus

  • Frazil ice
  • Posts: 287
    • View Profile
  • Liked: 120
  • Likes Given: 162
Re: 2018 sea ice area and extent data
« Reply #967 on: July 06, 2018, 03:44:59 PM »
The big question for me is: "Will Hudson Bay and Kara sea completely melt out?"

No reason to suppose Hudson Bay will not melt out completely. Already well over half gone.
Kara Sea will probably almost completely melt out as usual. Also well over half gone.
They are just a bit late this year.
Ditto to this.  The Kara and Hudson have melted out completely or almost completely for the last 15 years.  But I realize it is perfectly possible that you were being ironical.  If so, I have felt the burn on this issue, and I have been converted (with much reluctance) to emoticons.  May I recommend  :o or  ;D or  8) ....   

I think you highlight that we should remember that these melting seas will continue to add to the magnitude of extent and area drops through July -- something well worth remembering.
« Last Edit: July 06, 2018, 04:11:14 PM by Pagophilus »

Pagophilus

  • Frazil ice
  • Posts: 287
    • View Profile
  • Liked: 120
  • Likes Given: 162
Re: 2018 sea ice area and extent data
« Reply #968 on: July 06, 2018, 04:14:17 PM »
Agreed on the first two points, but we are seeing the ESS and Chukchi taking a lot of heat right now ...  I hope you are right, but there is a long ways to go yet.


The atlantc side is skewing the inner basin drops.

The Pacific side has been well protected.

So a slow down is very likely as we go along

Juan C. García

  • Nilas ice
  • Posts: 1533
    • View Profile
  • Liked: 547
  • Likes Given: 518
Re: 2018 sea ice area and extent data
« Reply #969 on: July 07, 2018, 05:50:49 AM »
[ADS-NIPR-JAXA] ASI Extent.

July 6th, 2018: 8,945,371 km2, a drop of -67,709 km2.
2018 is the tenth 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.

gerontocrat

  • First-year ice
  • Posts: 6824
    • View Profile
  • Liked: 1727
  • Likes Given: 22
Re: 2018 sea ice area and extent data
« Reply #970 on: July 07, 2018, 11:17:56 AM »
JAXA Arctic Sea Ice Extent - 8,945,371 km2(July 6, 2018)

A daily drop of just 68k, about 25k less than the average for the time of year.
Extent loss to date is 690k km2 (12.2%) below the 2010's average, with 57% of the average melting season done.
Resulting minimum from average remaining melt = 4.62 million km2, (excluding 2012 from the average 4.72 million km2). Range of results from last ten years is 3.70 to 5.28 million km2.

There is, on average, just 43% of further extent loss to go. Within three weeks daily extent loss is, on average, already in decline. A September minimum of 4.5 to 5.0 million km2 looks more likely every day.
[/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)

gerontocrat

  • First-year ice
  • Posts: 6824
    • View Profile
  • Liked: 1727
  • Likes Given: 22
Re: 2018 sea ice area and extent data
« Reply #971 on: July 07, 2018, 02:39:44 PM »
NSIDC Total Area as at 6 July (5 day trailing average =  6,876,736 km2
This is down to 224 k above the 2010-2017 average

 
Total Area loss 153K, Central Seas 113k, Periphery loss 219 k, Other Seas loss 21 k  

Analysis of individual seas.

Pacific Side
- The Okhotsk Sea area is 4,
- The Bering Sea area is 2 k,
- Chukchi Sea loss 16 k,
- Beaufort Sea loss 6 k,

Atlantic Side
- Total area loss of the Baffin, Greenland, and Barents Seas 19 k,
of which the Baffin Sea loss was 11 k, the Greenland Sea loss 5k,and  the Barents Sea loss 3 k
- The Kara Sea area loss 13 k.
- The Laptev Sea area loss 18 k  .

CAB
- The Central Arctic Sea loss 15 k
- The Canadian Archipelago loss 3 k
- East Siberian Sea loss 42 k (106k in three days)

Other seas
- St Lawrence area at 1 k,
- Hudson Bay area loss 17 k.

Area loss accelerated a bit over the last few days - though NSIDC Area is still sitting between the 2010's average and the 2000's average, very much as in JAXA EXTENT.

Added NSIDC concentration map as at 6 July.
"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)

Stephan

  • Grease ice
  • Posts: 803
    • View Profile
  • Liked: 271
  • Likes Given: 141
Re: 2018 sea ice area and extent data
« Reply #972 on: July 07, 2018, 08:10:11 PM »
East Siberian Sea had been "asleep" for almost the whole melting season this year. The extraordinary high temperatures that arrived there a week ago or so (max. around 20-30° according to Climate Reanalyzer) now start the big melt there...
It is too late just to be concerned about Climate Change

Juan C. García

  • Nilas ice
  • Posts: 1533
    • View Profile
  • Liked: 547
  • Likes Given: 518
Re: 2018 sea ice area and extent data
« Reply #973 on: July 08, 2018, 05:57:08 AM »
[ADS-NIPR-JAXA] ASI Extent.

July 7th, 2018: 8,884,111 km2, a drop of -61,260 km2.
2018 is the tenth lowest on record [and tomorrow could become the 11th  8) ]
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

  • First-year ice
  • Posts: 6824
    • View Profile
  • Liked: 1727
  • Likes Given: 22
Re: 2018 sea ice area and extent data
« Reply #974 on: July 08, 2018, 07:55:17 AM »
JAXA Arctic Sea Ice Extent - 8,884,111 km2(July 7, 2018)

Once again, Just to add to Juan's post:-
- A daily drop of just 61k, about 30k less than the average for the time of year.
Extent loss to date is 720k km2 (12.6%) below the 2010's average, with 58% of the average melting season done.
Resulting minimum from average remaining melt = 4.65 million km2, (excluding 2012 from the average 4.76 million km2). Range of results from last ten years is 3.69 to 5.32 million km2.

There is, on average, just 42% of further extent loss to go. Within three weeks daily extent loss is, on average, already in decline. A September minimum of 4.5 to 5.0 million km2 looks more (and more) likely every day.
"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)

pauldry600

  • Frazil ice
  • Posts: 201
    • View Profile
    • weathergossip
  • Liked: 9
  • Likes Given: 3
Re: 2018 sea ice area and extent data
« Reply #975 on: July 08, 2018, 11:50:16 AM »
This is because we in the British Isles are getting a Summer.

When we get a Summer the Arctic melt is slow.

Thats why Im sure JAXA will end 4.5 to 5m

Jim Pettit

  • Global Moderator
  • Nilas ice
  • *****
  • Posts: 1177
    • View Profile
  • Liked: 40
  • Likes Given: 11
Re: 2018 sea ice area and extent data
« Reply #976 on: July 08, 2018, 03:28:38 PM »
JAXA Arctic SIE is still on its very slow decline, seeing its 15th consecutive day--and 29th out of the last 31--with a decline less than the 10-year (2008-2017) average.

2018 has also seen the longest May/June/July stretch on record with no century decreases. The last century break was on May 5, and, in fact, there have only been two so far this year. By way of comparison, the 10-year average by this date has been 9.7, with 2012 seeing 23 by now.

(Last sentence edited; thanks Ned W)
« Last Edit: July 08, 2018, 11:06:54 PM by Jim Pettit »

gerontocrat

  • First-year ice
  • Posts: 6824
    • View Profile
  • Liked: 1727
  • Likes Given: 22
Re: 2018 sea ice area and extent data
« Reply #977 on: July 08, 2018, 03:44:31 PM »
NSIDC Total Area as at 7 July (5 day trailing average =  6,690,737 km2
This is down to just 137 k above the 2010-2017 average


Total Area loss 186K, Central Seas 141 k, Periphery loss 20 k, Other Seas loss 25 k  

Analysis of individual seas.

Pacific Side
- The Okhotsk Sea area is 4k,
- The Bering Sea area is 2 k,
- Chukchi Sea loss 9 k,
- Beaufort Sea loss 11 k,

Atlantic Side
- Total area loss of the Baffin, Greenland, and Barents Seas 120 k,
of which the Baffin Sea loss was 7 k, the Greenland Sea loss 10 k,and  the Barents Sea loss 3 k
- The Kara Sea area loss 14 k.
- The Laptev Sea area loss 14 k  .

CAB
- The Central Arctic Sea loss 50 k
- The Canadian Archipelago loss 9 k
- East Siberian Sea loss 33 k (140 k in four days)

Other seas
- St Lawrence area at 2 k,
- Hudson Bay area loss 25 k.

Area loss accelerated somewhat over the last few days - NSIDC Area now down close to the 2010's average (see graph below). This is not yet reflected in JAXA EXTENT rate of loss.
« Last Edit: July 08, 2018, 04:56:11 PM by gerontocrat »
"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)

Ned W

  • Guest
Re: 2018 sea ice area and extent data
« Reply #978 on: July 08, 2018, 03:47:11 PM »
2018 has also seen the longest May/June/July stretch on record with no century decreases. The last century break was on May 5, and, in fact, there have only been two so far this year. By way of comparison, the 10-year average by this date has been 19, with 2012 seeing 40 by now.

Are you quite sure of that?  I get rather smaller numbers - a ten-year average (2008-2017) of 9.7, a maximum of 23 (in 2012), and the following for each year:

20033
20047
20054
20068
200711
20084
20099
20109
20118
201223
201313
201413
20157
20165
20176
20182

Disclaimer: I am on my way out the door and rushed through this calculation in a hurry.  I probably messed something up and am making a fool of myself by hitting "Post". 

 :)

---------------

Edited to add: Jim, is it possible that you're comparing 2018's year-to-date value (for number of century breaks) to previous years' 365-day totals, rather than year-to-date?  Because if I do that, I do get a value of 40 for 2012, and a ten-year average of 19.4, which match yours.

2018 is still an outlier -- the fewest in the 2003-present JAXA daily record, and only 20% of the ten-year average.
« Last Edit: July 08, 2018, 03:53:16 PM by Ned W »

Stephan

  • Grease ice
  • Posts: 803
    • View Profile
  • Liked: 271
  • Likes Given: 141
Re: 2018 sea ice area and extent data
« Reply #979 on: July 08, 2018, 03:58:25 PM »
This is now 10 almost consecutive days of a "century loss" in area - will this trend continue? And will it also be visible soon in the extent data?
It is too late just to be concerned about Climate Change

Neven

  • Administrator
  • First-year ice
  • *****
  • Posts: 7209
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 732
  • Likes Given: 477
Re: 2018 sea ice area and extent data
« Reply #980 on: July 08, 2018, 04:25:42 PM »
As long as area keeps dropping fast , and extent doesn't respond, compactness will drop fast too. Right now it's lowest in the 2005-2018 record:
Il faut comparer, comparer, comparer, et cultiver notre jardin

Stephan

  • Grease ice
  • Posts: 803
    • View Profile
  • Liked: 271
  • Likes Given: 141
Re: 2018 sea ice area and extent data
« Reply #981 on: July 08, 2018, 04:58:07 PM »
This plot shows a big variety in compactness. Less than a month ago we saw a maximum and now a minimum. I suggest a return to the "middle of the pack" soon - by a remarkable extent loss in the next week(s). Let's re-visit this hypothesis end of July...
It is too late just to be concerned about Climate Change

Ned W

  • Guest
Re: 2018 sea ice area and extent data
« Reply #982 on: July 08, 2018, 06:04:02 PM »
Isn't that basically the story of 2018, so far?

(1) We started out in May with abnormally high compactness and thus relatively low extent. 

(2) Over the past five weeks, there was a big decrease in area, but also a huge decrease in compactness, from (near) record-high to (near) record-low.  So extent loss slowed to a crawl.

This can be seen in the JAXA daily predictions for the end-of-season minimum.  I noted the hockey-stick shape a few days ago:



Looking ahead ... as Stephan says, it seems unlikely that the ssslllooowww extent decreases will continue.  Something's gotta change there.  I'm surprised it's lasted this long, actually.  Not many years have such a radical change in compactness during the melt season.

Dharma Rupa

  • Frazil ice
  • Posts: 493
    • View Profile
  • Liked: 55
  • Likes Given: 26
Re: 2018 sea ice area and extent data
« Reply #983 on: July 08, 2018, 06:11:05 PM »
Looking ahead ... as Stephan says, it seems unlikely that the ssslllooowww extent decreases will continue.  Something's gotta change there.  I'm surprised it's lasted this long, actually.  Not many years have such a radical change in compactness during the melt season.

Not clear to me anything will change during the summer, but it wouldn't surprise me too much if Winter took a vacation.

I'll be looking very carefully at how quickly the seas fill with ice come Fall.

Ned W

  • Guest
Re: 2018 sea ice area and extent data
« Reply #984 on: July 08, 2018, 06:12:52 PM »
Here's the chart version of the table I posted earlier -- number of JAXA extent century breaks so far this year, compared to the same period in previous years:



Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4009
    • View Profile
    • Arctische Pinguin
  • Liked: 644
  • Likes Given: 0
Re: 2018 sea ice area and extent data
« Reply #985 on: July 08, 2018, 07:20:53 PM »
Remarkable: -163k loss in NSIDC extent, of which Hudson takes -150k.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2018-07-07 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4323.3   -6.6  -117.6    915.0   +3.9   +10.9    397.1   +0.1  -268.6
               Kara Sea             Barents Sea           Greenland Sea
   610.9  -16.7  -129.8     64.7   -4.8  -209.7    278.6   +6.1  -239.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   547.4  +23.4   +10.6      5.7   +0.5    +5.7    567.7 -149.5   -61.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   694.3   +0.0    -3.4    436.1  -25.1    +3.7    269.9   +7.6  -134.1
             Bering Sea          Sea of Okhotsk                   Lakes
     3.0   +0.6    -1.7     13.6   -2.8   +13.6    218.8  -21.7   +83.4
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   9130.2 -163.1 -1118.0

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3581.8 -131.8  -290.8    625.1  +24.7   -45.8    195.1   +0.3  -270.3
               Kara Sea             Barents Sea           Greenland Sea
   301.9  -12.6  -185.3     21.6   -2.9  -122.4    153.9  -18.9  -108.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   256.6   +0.8   -38.4      1.7   +0.0    +1.7    306.6  -62.4   -17.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   475.9  -19.3   -33.0    272.1   -7.5   -32.4    164.0  +10.8  -121.9
             Bering Sea          Sea of Okhotsk                   Lakes
     1.7   +0.1    +0.5      3.7   -1.4    +3.7    102.7   -3.3   +39.9
          Other regions       Total (ex. lakes)
     2.2   -0.0    +2.2   6364.0 -220.2 -1257.8



jdallen

  • Young ice
  • Posts: 3024
    • View Profile
  • Liked: 190
  • Likes Given: 172
Re: 2018 sea ice area and extent data
« Reply #986 on: July 08, 2018, 07:21:37 PM »
As long as area keeps dropping fast , and extent doesn't respond, compactness will drop fast too. Right now it's lowest in the 2005-2018 record:
I've been watching the divergence in behavior between area and extent with considerable interest.

I think it speaks to the fundamental changes in the structure of the pack.  I'm hesitant to make any specific conclusions about it yet, but anecdotally it appears we are seeing more smaller floes being dispersed over a larger area, and a lot more melting inside the core extent of the pack than we've typically seen in the past.  That there may be the key distinction between 2018 and previous melt seasons.

[Edit:]  A pack with smaller more mobile floes would also help explain the wide variation in and rapid changes to compactness.
This space for Rent.

Neven

  • Administrator
  • First-year ice
  • *****
  • Posts: 7209
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 732
  • Likes Given: 477
Re: 2018 sea ice area and extent data
« Reply #987 on: July 08, 2018, 09:34:18 PM »
Here's the chart version of the table I posted earlier -- number of JAXA extent century breaks so far this year, compared to the same period in previous years:


Keep in mind that the amount of century breaks for 2012 is somewhat inflated, because the numbers are based on Windsat, as the dataset hovered between AMSR-E and AMSR2.

I've been watching the divergence in behavior between area and extent with considerable interest.

I think it speaks to the fundamental changes in the structure of the pack.  I'm hesitant to make any specific conclusions about it yet, but anecdotally it appears we are seeing more smaller floes being dispersed over a larger area, and a lot more melting inside the core extent of the pack than we've typically seen in the past.  That there may be the key distinction between 2018 and previous melt seasons.

[Edit:]  A pack with smaller more mobile floes would also help explain the wide variation in and rapid changes to compactness.

That's possible, but it could also be that compactness is now finally going down because there's widespread melt ponding on the Siberian side of the Arctic (and divergence in the Beaufort/Chukchi). I'm not sure if resolution is high enough to catch what you're describing (change in the pack structure). The compactness graphs I'm posting are based on NSIDC extent and area, which have really low resolution (25 km vs 3.125 km for AMSR2).
Il faut comparer, comparer, comparer, et cultiver notre jardin

Steven

  • Grease ice
  • Posts: 555
    • View Profile
  • Liked: 133
  • Likes Given: 16
Re: 2018 sea ice area and extent data
« Reply #988 on: July 08, 2018, 10:19:57 PM »
As long as area keeps dropping fast , and extent doesn't respond, compactness will drop fast too. Right now it's lowest in the 2005-2018 record:

Indeed, there has been a "July Cliff" for NSIDC sea ice area in the past week:



But weather forecasts seem to be favorable for ice retention in the next several days, so I guess there will be a reduction in melt ponding and the cliff will fizzle out (and maybe bounce back upwards a bit, although that remains to be seen...)

Jim Pettit

  • Global Moderator
  • Nilas ice
  • *****
  • Posts: 1177
    • View Profile
  • Liked: 40
  • Likes Given: 11
Re: 2018 sea ice area and extent data
« Reply #989 on: July 08, 2018, 11:29:40 PM »
Edited to add: Jim, is it possible that you're comparing 2018's year-to-date value (for number of century breaks) to previous years' 365-day totals, rather than year-to-date?

You are correct; I'd never bothered calculating that metric before, so I inadvertently threw in the whole-year instead of YTD count. Thanks for pointing that out. Still, while the difference isn't nearly as stark, it is indeed noticeable; the current YTD count of 2 is two standard deviations below that average of 9.7, and something you'd expect to see just two or three times every 100 years. (And, yes, I realize the sample size is too small to draw any meaningful conclusions.)

(FWIW, generally-speaking, a direct message to the OP will trigger an email, and that almost always means a quicker correction.)

Juan C. García

  • Nilas ice
  • Posts: 1533
    • View Profile
  • Liked: 547
  • Likes Given: 518
Re: 2018 sea ice area and extent data
« Reply #990 on: July 09, 2018, 05:56:07 AM »
[ADS-NIPR-JAXA] ASI Extent.

After only 2 century breaks on 2018, finally another century break:
 
July 8th, 2018: 8,762,912 km2, a drop of -121,199 km2.
2018 is still the tenth 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.

gerontocrat

  • First-year ice
  • Posts: 6824
    • View Profile
  • Liked: 1727
  • Likes Given: 22
Re: 2018 sea ice area and extent data
« Reply #991 on: July 09, 2018, 07:59:47 AM »
JAXA Arctic Sea Ice Extent - 8,762,912 km2(July 8, 2018)

Once again, Just to add to Juan's post:-
- A daily drop of just 121k, about 30k GREATER than the average for the time of year.
Extent loss to date is 690k km2 (11.9%) below the 2010's average, with 58% of the average melting season done.
Resulting minimum from average remaining melt = 4.62 million km2, (excluding 2012 from the average 4.73 million km2). Range of results from last ten years is 3.68 to 5.30 million km2.

Perhaps JAXA extent losses will, over the next few days, catch up a bit with the greater than average area losses recoreded by NSIDC over the last few days. However, there is, on average, just 42% of further extent loss to go. Within three weeks daily extent loss, on average, will be already in decline. A September minimum of 4.5 to 5.0 million km2 looks more (and more) likely every day.
"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: 6824
    • View Profile
  • Liked: 1727
  • Likes Given: 22
Re: 2018 sea ice area and extent data
« Reply #992 on: July 09, 2018, 02:31:25 PM »
NSIDC Total Area as at 8 July (5 day trailing average =  6,540,856 km2
This is down to just 81 k above the 2010-2017 average


Total Area loss 150K, Central Seas 107 k, Periphery loss 22 k, Other Seas loss 21 k  

Analysis of individual seas.

Pacific Side
- The Okhotsk Sea area is 5k,
- The Bering Sea area is 2 k,
- Chukchi Sea loss 4 k,
- Beaufort Sea loss 7 k,
Area loss slowed.
Atlantic Side
- Baffin Sea loss 8 k,
- Greenland Sea loss 12 k,
- Barents Sea loss 2 k
- The Kara Sea area loss 10 k.
- The Laptev Sea area loss 6 k  .

CAB
- The Central Arctic Sea loss 57 k,
- The Canadian Archipelago loss 9 k,
- East Siberian Sea loss 14 k .

Other seas
- St Lawrence area at 2 k,
- Hudson Bay area loss 21 k.

Area loss accelerated somewhat over the last few days - NSIDC Area now down close to the 2010's average (see graph below). JAXA EXTENT loss was 121k - more century breaks to come?
"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)

Feeltheburn

  • Frazil ice
  • Posts: 199
    • View Profile
  • Liked: 9
  • Likes Given: 1
Re: 2018 sea ice area and extent data
« Reply #993 on: July 10, 2018, 02:38:13 AM »
The good times may not last, but July 8, 2018 is now closer to July 8, 1995 than July 8, 2017 according to NSIDC:

In ascending order:

2011 - 8.537
2016 - 8.559
2012 - 8.572
2017 - 8.681
2014 - 8.708
2007 - 8.722
2010 - 8.746
2013 - 8.909
2006 - 9.045
2018 - 9.201
2009 - 9.292
2015 - 9.304
2005 - 9.355
2008 - 9.450
2001 - 9.578
1995 - 9.672




Feel The Burn!

Juan C. García

  • Nilas ice
  • Posts: 1533
    • View Profile
  • Liked: 547
  • Likes Given: 518
Re: 2018 sea ice area and extent data
« Reply #994 on: July 10, 2018, 03:31:03 AM »
[ADS-NIPR-JAXA] ASI Extent Analysis.

On July 17th, there is an important difference between the 7th and the 8th lowest, that is, between 2014 and 2010. So, it is possible that 2018 will become the 8th lowest on record that day, if it has an average drop between 93.9 and 131.8K km2.

Will it make it?

We can use the table to calculate were 2018 will be, given the average drops that 2018 will have on the following days.
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

  • Nilas ice
  • Posts: 1533
    • View Profile
  • Liked: 547
  • Likes Given: 518
Re: 2018 sea ice area and extent data
« Reply #995 on: July 10, 2018, 05:51:42 AM »
[ADS-NIPR-JAXA] ASI Extent.

July 9th, 2018: 8,737,858 km2, a drop of only -25,054 km2.
(Very small drop, on this time of the year).

2018 is still the tenth 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.

gerontocrat

  • First-year ice
  • Posts: 6824
    • View Profile
  • Liked: 1727
  • Likes Given: 22
Re: 2018 sea ice area and extent data
« Reply #996 on: July 10, 2018, 07:38:44 AM »
JAXA Arctic Sea Ice Extent - 8,737,858 km2(July 9, 2018)

Once again, Just to add to Juan's post:-
- A daily drop of just 25k is about 65 to 70 k less than the average for the time of year,
- Extent is 422k (4.8%) below the 2010's average extent on this date,
- Extent loss to date is 770k km2 (12.9%) below the 2008-2017 average, with 59% of the average melting season done.

Resulting minimum from average remaining melt = 4.69 million km2, (excluding 2012 from the average 4.79 million km2). Range of results from last ten years is 3.81 to 5.39 million km2.

Yesterday, I said :-
Quote
Perhaps JAXA extent losses will, over the next few days, catch up a bit with the greater than average area losses recorded by NSIDC over the last few days.

Now I am getting that 2017 feeling - a big extent loss one day merely flatters to deceive. There is, on average, just 41% of further extent loss to go. In less than three weeks daily extent loss, on average, will be already in significant decline. A September minimum of 4.5 to 5.0 million km2 looks more and more) likely every day.

Thus the divergence between extent and area seems set to increase. Perhaps this deserves a look-see at the end of the melting season for each sea (using NSIDC 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)

colchonero

  • New ice
  • Posts: 88
    • View Profile
  • Liked: 13
  • Likes Given: 2
Re: 2018 sea ice area and extent data
« Reply #997 on: July 10, 2018, 12:20:59 PM »
Gerontocrat (or somebody else who knows the answer :D), I have to ask does Jaxa provide/calculate new "numbers" or "stats" (Idk how should I call it) every day, or is it 2-day average?

gerontocrat

  • First-year ice
  • Posts: 6824
    • View Profile
  • Liked: 1727
  • Likes Given: 22
Re: 2018 sea ice area and extent data
« Reply #998 on: July 10, 2018, 12:22:52 PM »
Gerontocrat (or somebody else who knows the answer :D), I have to ask does Jaxa provide/calculate new "numbers" or "stats" (Idk how should I call it) every day, or is it 2-day average?
2 day.
"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)

colchonero

  • New ice
  • Posts: 88
    • View Profile
  • Liked: 13
  • Likes Given: 2
Re: 2018 sea ice area and extent data
« Reply #999 on: July 10, 2018, 12:33:53 PM »
Ok thanks, then I think if my math is correct, we can see an increase tomorrow, if there is not much melting today, because we had some 60k drops for a couple of days. and then yesterday 2-day average came down to 120k. So it should mean that there was a 170-180k drop yesterday. So I was expecting another bigger than average drop today. But today we are seeing a 2 day average drop of only 25k with that big one from yesterday counting. So that means there was a substantial increase in extent by Jaxa calculations.