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bbr2314

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Re: 2018 sea ice area and extent data
« Reply #450 on: April 18, 2018, 10:01:55 AM »
Any chance of leaving one thread for data. It is getting a little to much marching through "snow drifts" on every thread. Thanks
Do you think ice melts without reason? I didn't post any maps. I posted analysis. If you find ignorance blissful I suggest putting me on ignore.

binntho

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Re: 2018 sea ice area and extent data
« Reply #451 on: April 18, 2018, 10:10:53 AM »
Any chance of leaving one thread for data. It is getting a little to much marching through "snow drifts" on every thread. Thanks
Do you think ice melts without reason? I didn't post any maps. I posted analysis. If you find ignorance blissful I suggest putting me on ignore.
This snow thing might be interesting but it's annoying having it drift into the wrong discussions. How about putting it all in Land snow cover effect on sea ice where it belongs?
because a thing is eloquently expressed it should not be taken to be as necessarily true
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bbr2314

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Re: 2018 sea ice area and extent data
« Reply #452 on: April 18, 2018, 10:14:47 AM »
Any chance of leaving one thread for data. It is getting a little to much marching through "snow drifts" on every thread. Thanks
Do you think ice melts without reason? I didn't post any maps. I posted analysis. If you find ignorance blissful I suggest putting me on ignore.
This snow thing might be interesting but it's annoying having it drift into the wrong discussions. How about putting it all in Land snow cover effect on sea ice where it belongs?

...so I am supposed to comment on sea ice area without mentioning the reasoning behind my predictions!?!?! What is it with you people

Sea ice and snowcover are a COUPLED SYSTEM and intrinsically linked, discussion of one without the other is why we are sitting in a spiraling AGW situation with no idea what is coming around the corner. Segmenting discourse and reason from one another is the opposite intent of this forum (IMO).

If you cannot discuss the merits of the arguments of course you attack the fact that the arguments are being made at all...

be cause

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Re: 2018 sea ice area and extent data
« Reply #453 on: April 18, 2018, 10:40:34 AM »
bbr .. 'you people' are your readership .. and abusing us is scarcely the way to bring us flocking to the Guru's feet . This thread is for data not arguments about what you think might happen (see title ! ). Some folks are even taking a holiday from posting as seeing every thread snowed on is no more beneficial than a forum filled with AGW deniers . Please review your methodology .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 + 2 = 2021 
 (phew)

bbr2314

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Re: 2018 sea ice area and extent data
« Reply #454 on: April 18, 2018, 10:42:41 AM »
bbr .. 'you people' are your readership .. and abusing us is scarcely the way to bring us flocking to the Guru's feet . This thread is for data not arguments about what you think might happen (see title ! ). Some folks are even taking a holiday from posting as seeing every thread snowed on is no more beneficial than a forum filled with AGW deniers . Please review your methodology .. b.c.

2018 is going to hemorrhage in Okhotsk, Baffin, Bering, Beaufort, and Chukchi over the next thirty days. I would not be surprised to see its lead expanded. 2016 had significantly more volume in the way of the Pacific -- 2018 is in very dire straits, especially ^.

The ATL side in Barentz may actually mask losses as melt is matched by import. But this will probably end by 6/1, at latest.

I do anticipate Hudson Bay will hold up phenomenally well this year, with some ice possibly even making it through summer. But that is still unlikely, and will probably lead to sustained drops in the very late season (late July/August instead of May/June).


What is off-topic about the above?!?!?!

I am not a Guru and I do not care if you want to lick my feet or not. It is up to you to pursue your foot fetish.

Neven

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Re: 2018 sea ice area and extent data
« Reply #455 on: April 18, 2018, 10:47:17 AM »
What is off-topic about the above?!?!?!

This thread is about discussing area and extent data as it comes in, not about what is going to happen the next 30 days and how snow plays a major role in it.

Keep it short in the Melting Season thread, and do whatever you like in the NH snow cover thread. Shut up about snow over here.
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bbr2314

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Re: 2018 sea ice area and extent data
« Reply #456 on: April 18, 2018, 10:48:26 AM »
What is off-topic about the above?!?!?!

This thread is about discussing area and extent data as it comes in, not about what is going to happen the next 30 days and how snow plays a major role in it.

Keep it short in the Melting Season thread, and do whatever you like in the NH snow cover thread. Shut up about snow over here.
Will do  8)

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #457 on: April 18, 2018, 11:23:36 AM »
JAXA DATA AS AT 17TH APRIL 2018 12,985,833 KM2

2018 extent below 13 million km2 4 days before 2017, and just one day before 2016. On average 8.4% of the extent loss done. A bit too early in the season to get hyperbolic about melting prospects.

Nevertheless, an impressive extent loss of 270,000 km2 in just 4 days and of fairly consistent amounts? Also one day closer to a minimum of below 4 million km2. Worth keeping an eye on.
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Phil42

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Re: 2018 sea ice area and extent data
« Reply #458 on: April 18, 2018, 11:26:05 AM »
Since we hit the 13 million km2 extent mark now, I decided to look at the dates when the extent hit this mark in previous years. I ordered them by the date it hit the mark and added the decade averages.

ASI Extent first time below 13 million km2 by year (JAXA):
2018: April 17
2016: April 19
2017: April 21
2004: April 22
2007: April 24
2006, 2014, 2015: April 26
2010's Average: April 28
2000's Average: May 4
1990's Average: May 13
1980's Average: May 21

edit: Looks like gerontocrat was faster than me, I'll leave the post up anyway.
« Last Edit: April 18, 2018, 11:32:50 AM by Phil42 »

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #459 on: April 18, 2018, 01:47:57 PM »

2010's Average: April 28
2000's Average: May 4
1990's Average: May 13
1980's Average: May 21

edit: Looks like gerontocrat was faster than me, I'll leave the post up anyway.

I am sure all who look at this thread agree that all data is welcome, especially data like that from you showing the more than one month difference between now (2016 to 2018) and then (1980's). A good measure of how far the melt has got.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #460 on: April 18, 2018, 02:19:21 PM »
A LOOK AT AREA

NSIDC AREA - 5 day trailing average

When looking at extent the data says nothing is happening outside the peripheral seas (e.g. Bering, Okhotsk, St Lawrence). But the change has happened when one looks at area. Hudson Bay, .
Chukchi and Laptev have just started to lose measurable area.

Summary in table below.
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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #461 on: April 19, 2018, 05:50:15 AM »
JAXA ASIE April 18th, 2018: 12,938,678 km2, a drop of -47,155 km2.
2018 is the lowest on record.
2018 is now 57,915 km2 under 2016.
 
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: 2018 sea ice area and extent data
« Reply #462 on: April 19, 2018, 11:29:41 AM »
JAXA EXTENT AT 18 APRIL

To add to Juan's post just
- that 2018 extent is also 105,817 km2 (3 days) below 2017,
- that for 63 days out of 108 2018 daily extent has been at a record low in the satellite record,
- extent loss has been 316,749 km2 in the last 5 days.

"Para a Causa do Povo a Luta Continua!"
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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #463 on: April 20, 2018, 05:56:59 AM »
JAXA ASI Extent.
April 19th, 2018: 12,888,393 km2, a drop of -50,285 km2.
2018 is the lowest on record.
2018 is now -39,724 km2 under 2016.
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.

LRC1962

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Re: 2018 sea ice area and extent data
« Reply #464 on: April 20, 2018, 08:03:27 AM »
JAXA ASI Extent.
April 19th, 2018: 12,888,393 km2, a drop of -50,285 km2.
2018 is the lowest on record.
2018 is now -39,724 km2 under 2016.
I 'Liked' this, Actually should for each one, but most times I come on it is more to see what is happening then quickly leave. Not very kind to the forum, but what value I can add is very bad from education standards. On the otherhand liking it leaves me with a very sick feeling, because the legacy my generation has left (over 55) the next many generations will be paying a very high price for their entire lifetimes.
Keep the data coming because you are recording history and there are very few sites that are doing a very good job of it, and right now governments seem to be doing more and more to erase it.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #465 on: April 20, 2018, 08:27:34 AM »
JAXA EXTENT AT 19 APRIL

To add to Juan's post just
- that 2018 extent is also -145,302 km2 (3 days) below 2017,
- that for 64 days out of 109 2018 daily extent has been at a record low in the satellite record,
- that extent loss has been -367,034  km2 in the last 6 days, above average for the time of year, but not enormously so.

The low March maximum and early strong melt is very significant for the positive feedback of albedo warming potential. We are just entering the maximum insolation season of the next 4 months or so (last graph attached from https://sites.google.com/site/cryospherecomputing/awp ).
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #466 on: April 20, 2018, 02:39:36 PM »
NSIDC AREA DATA AS AT 19 APRIL

Being the 5 day average the data shows better the gradual acceleration of daily area loss from under 20,000 km2 per day one week ago to approaching 50,000 km2 per day now.

Of interest is that Hudson Bay is losing area quite strongly at the moment despite all that snow in that corner of N. America.
The Chukchi Sea is also starting to show significant melt (Bering Strait is pretty well open now?)

NSIDC Arctic Total Extent down 91k, but still second to 2016.
« Last Edit: April 20, 2018, 03:01:44 PM by gerontocrat »
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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #467 on: April 20, 2018, 08:13:28 PM »
JAXA Analysis:

On April 30th, the year 2016 is the lowest on record, with 12,293,447 km2. 2018 will have to drop a daily average of 54.1K km2, to continue been the lowest on record on April 30th.

2006 is the second lowest on record on April 30th, with 12,661,451 km2. That is, 368K km2 above 2016. So, 2018 will be second lowest on record, if the daily average drop is less than 54.1 km2 but greater than 20.6K km2.

It is possible that 2018 drops more than 54.1K km2 average on the next 11 days, so I do not discard that could continue been the lowest on record. But I see a big probability that the average drop will be more than 20.6K km2. So, I think that -at least- 2018 will be second lowest on record at the end of April.

While the average drop of 2016 was 57.7K km2 on April 19-30, the average drop of 2012 was 75.4K km2. So, 2012 is already falling faster than 2006 and 2015-17.
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: 2018 sea ice area and extent data
« Reply #468 on: April 21, 2018, 06:03:45 AM »
JAXA ASI Extent.

April 20th, 2018: 12,854,880 km2, a drop of 33,513 km2.
2018 is the lowest on record.
2018 is now 23,075 km2 under 2016.
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: 2018 sea ice area and extent data
« Reply #469 on: April 21, 2018, 11:00:12 AM »
JAXA EXTENT AT 20 APRIL

To add to Juan's post simply that
- 2018 extent is again 145k km2 (3 days) below 2017,
- for 65 days out of 110 2018 daily extent has been at a record low in the satellite record,
- a 33k drop is pretty well average for this time of year.

Attachments show no real change from 19th April
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #470 on: April 21, 2018, 03:27:34 PM »
NSIDC AREA ANALYSIS (5 day trailing average data) as at 20 April 2018

It is the Pacific side that is showing the most area losses - the Okhotsk, the Bering and now the Chukchi seas. This is likely to continue for at least a few days more. There is real day-time warmth up there now (see map attached)

On the Atlantic side, zilch area loss on the 20th after a few days of modest losses in the Kara and Laptev for a few days before.

Despite all that snow, Hudson Bay is losing area, though it is a bit late this year. (A post said that Churchill was at 12 celsius and sunny yesterday).

Area loss is at well over 40,000 km2 per day.
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mitch

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Re: 2018 sea ice area and extent data
« Reply #471 on: April 21, 2018, 06:42:09 PM »
The Chukchi Sea region is still cold enough to resurface itself with ice when big open ocean areas form.  This will stop soon, so I expect to see major drops in ice extent soon.

bbr2314

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Re: 2018 sea ice area and extent data
« Reply #472 on: April 21, 2018, 09:33:24 PM »
The Chukchi Sea region is still cold enough to resurface itself with ice when big open ocean areas form.  This will stop soon, so I expect to see major drops in ice extent soon.
The Chukchi and Beaufort are going to begin opening wide and clear within the next 10 days. It is going to be a sight to see! More like a zipper instead of a gradual march.

Dharma Rupa

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Re: 2018 sea ice area and extent data
« Reply #473 on: April 22, 2018, 12:15:57 AM »
On the Atlantic side, zilch area loss on the 20th after a few days of modest losses in the Kara and Laptev for a few days before.

Is there any way for us to get some estimate of export into this section?  How much is melting that is hidden in the lack of change in the extent?

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #474 on: April 22, 2018, 01:26:29 AM »

Is there any way for us to get some estimate of export into this section?  How much is melting that is hidden in the lack of change in the extent?
My regional postings are from NSIDC area - 5 day trailing average, which smooths daily data.

Fram export is confined to the Greenland sea. As far as I can see, unlike 2012, vast amounts of ice are not being hurled into the other Atlantic seas.

Therefore, in my totally not humble opinion ( IM not HO), Barents, Kara, Laptev are the ones to look at at this time of year for ice extent /area loss.

It is what the Arctic does, or used to do. Melt for a few days, go to sleep, do it again. I was expecting to only have to post the tables once a week or so in the main part of the melting season. Just my luck to look at area this year.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #475 on: April 22, 2018, 01:46:13 AM »
The Chukchi Sea region is still cold enough to resurface itself with ice when big open ocean areas form.  This will stop soon, so I expect to see major drops in ice extent soon.
The Chukchi and Beaufort are going to begin opening wide and clear within the next 10 days. It is going to be a sight to see! More like a zipper instead of a gradual march.

Re: 2018 sea ice area and extent data. DATA!!!!!!!
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DavidR

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Re: 2018 sea ice area and extent data
« Reply #476 on: April 22, 2018, 04:43:05 AM »
The Chukchi Sea region is still cold enough to resurface itself with ice when big open ocean areas form.  This will stop soon, so I expect to see major drops in ice extent soon.
The Chukchi and Beaufort are going to begin opening wide and clear within the next 10 days. It is going to be a sight to see! More like a zipper instead of a gradual march.

Nothing short of nuclear war between Alaska and Eastern Siberia would put enough energy into the system to acheive this. It  takes more than hot air to melt ice.

Chukchi and the Beaufort take about three months of steady decline to lose their ice. Over that period they will lose about 1 M km^2 in total; A rapid decline would be losing that in 10 weeks. or about 100K per week.  I expect an unspectacular decline in May due to the lack of ice in the Bering with the extent being somewhere near the 2015 (10.8-11.0M) figure by May 31st.   
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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #477 on: April 22, 2018, 06:10:11 AM »
JAXA ASI Extent.

April 21st, 2018: 12,816,110 km2, a drop of 38,770 km2.
2018 is the lowest on record.
2018 is now 21,024 km2 under 2016.
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.

jdallen

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Re: 2018 sea ice area and extent data
« Reply #478 on: April 22, 2018, 06:50:26 AM »
The Chukchi Sea region is still cold enough to resurface itself with ice when big open ocean areas form.  This will stop soon, so I expect to see major drops in ice extent soon.
The Chukchi and Beaufort are going to begin opening wide and clear within the next 10 days. It is going to be a sight to see! More like a zipper instead of a gradual march.

Nothing short of nuclear war between Alaska and Eastern Siberia would put enough energy into the system to acheive this. It  takes more than hot air to melt ice.

Chukchi and the Beaufort take about three months of steady decline to lose their ice. Over that period they will lose about 1 M km^2 in total; A rapid decline would be losing that in 10 weeks. or about 100K per week.  I expect an unspectacular decline in May due to the lack of ice in the Bering with the extent being somewhere near the 2015 (10.8-11.0M) figure by May 31st.   
Resurface with what? Nilas?

Ice in the Bering is *gone*.  Ice in the Chukchi is breaking up and retreating almost a month ahead of schedule.

I'm cognizant of the heat requirements to knock down the ice in the Beaufort and Chukchi, so I'm not anticipating a massive decline in May or even June, but I think we've passed the provenance of an 'unspectacular' decline, and the suggested persistent clear weather doesn't bode well for retention.
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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #479 on: April 23, 2018, 06:03:18 AM »
JAXA ASI Extent.

April 22nd, 2018: 12,808,509 km2, a small drop of 7,601 km2.
2018 is the second lowest on record.
2018 is 60,757 km2 above 2016.  ;)
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.

RikW

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Re: 2018 sea ice area and extent data
« Reply #480 on: April 23, 2018, 09:49:22 AM »
Recovery!

I'm curious to see if we will get a century-drop tomorrow to compensate...

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Re: 2018 sea ice area and extent data
« Reply #481 on: April 23, 2018, 10:17:07 AM »
Recovery!

I'm curious to see if we will get a century-drop tomorrow to compensate...

I think every lull will be followed by large declines, right now, because a lot of it is caused by last-ditch refreezing in the Chukchi. Okhotsk and Barentsz are also high and thus poised for big drops.

Whether it will be enough to keep up with 2016, I'm not sure.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #482 on: April 23, 2018, 03:08:14 PM »
NSIDC Arctic Total Extent (daily extent) at 22 April  13.395 million km2.
The contrast with JAXA data is pronounced.

Extent is down by 109k km2, lower than 2017 by 97k and lower than 2016 by 147k, i.e. lowest in the satellite record.

NSIDC AREA DATA (5 day trailing average) AS AT 22 APRIL


The peripheral seas continue to decline at just over 30k per day, but the central seas are not, showing a net gain of +9k per day for the last 2 days. Hudson Bay is the exception, consistently losing about 6k per day for the last week.

N.B. The daily extent loss of 109k will likely feed into greater area 5-day average daily losses in the next 4 days.

Of interest is that Hudson Bay is losing area quite strongly at the moment despite all that snow in that corner of N. America.
The Chukchi Sea is also starting to show significant melt (Bering Strait is pretty well open now?)

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Re: 2018 sea ice area and extent data
« Reply #483 on: April 23, 2018, 04:09:16 PM »
It looks like Hudson's bay will melt out early this year because the same weather that brought snow to eastern Canada helped bring in warm salty water that originated in the Gulf Stream and was advected around Iceland and Greenland into the Labrador sea. Labrador sea mixing went down to at least 2000m this late winter.

Ice is also melting rapidly offshore of the west coast of Greenland as the west Greenland current cranks up and advects heat northwards.

One piece of good news is that the weather has advected very little ice out of the Fram strait. There has been very little transport of ice out of the Arctic ocean all winter. The ice edge on the Barents sea has become the ice melting zone, but in the cold dark winter that's pretty good news for the ice.

bbr2314

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Re: 2018 sea ice area and extent data
« Reply #484 on: April 23, 2018, 04:23:07 PM »
It looks like Hudson's bay will melt out early this year because the same weather that brought snow to eastern Canada helped bring in warm salty water that originated in the Gulf Stream and was advected around Iceland and Greenland into the Labrador sea. Labrador sea mixing went down to at least 2000m this late winter.

Ice is also melting rapidly offshore of the west coast of Greenland as the west Greenland current cranks up and advects heat northwards.

One piece of good news is that the weather has advected very little ice out of the Fram strait. There has been very little transport of ice out of the Arctic ocean all winter. The ice edge on the Barents sea has become the ice melting zone, but in the cold dark winter that's pretty good news for the ice.

Do you see the ice that seems to be getting entrained into Hudson Strait from Baffin Bay? It is thick, possibly multi-yr ice. I wonder how long it survives and if this is just a day or two blip or the start of something new.

Shifting the bulk of winter transport from Fram to Nares must have some sort of downstream impact. Perhaps this is it? (an aggressive salinity push N)

binntho

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Re: 2018 sea ice area and extent data
« Reply #485 on: April 23, 2018, 05:36:55 PM »
It looks like Hudson's bay will melt out early this year because the same weather that brought snow to eastern Canada helped bring in warm salty water that originated in the Gulf Stream and was advected around Iceland and Greenland into the Labrador sea. Labrador sea mixing went down to at least 2000m this late winter.

Do you see the ice that seems to be getting entrained into Hudson Strait from Baffin Bay? It is thick, possibly multi-yr ice. I wonder how long it survives and if this is just a day or two blip or the start of something new.
Well you have me baffled guys! Looking at Worldview over the month of April, no ice has moved (been "entrained") into Hudson Bay or Hudson Strait. The ice shifts a bit one way and then another, but the main movement in Hudson Strait seems to be towards the south.

The ice streaming down Baffin Bay is melting out where the Hudson Strait meets the Baffin Bay. And I've never heard of weather being able to advect Gulf stream waters around Iceland and Greenland (no less) and down Baffin Bay!

The Baffin Current is a continuation of the West Greenland Current, which itself is a continuation of the cold East Greenland Current and the warm Irminger Current. Generally the currents run clockwise around the bay - the same route that the Ice is taking.
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Lord M Vader

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Re: 2018 sea ice area and extent data
« Reply #486 on: April 23, 2018, 06:21:34 PM »
Guys, you are forgetting that all that extra snow onto the ice in Hudson Bay will be transformed into water and exert pressure onto the ice which should melt even faster if the weather conditions are the right. While thick snow should be beneficial for the ice in the CAB the same might not be true for the peripheral ice.

Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #487 on: April 24, 2018, 05:44:40 AM »
JAXA ASI Extent.

April 23rd, 2018: 12,803,197 km2, a small drop of 5,312 km2.
2018 is the second lowest on record.
2018 is 121,524 km2 above 2016 and 24,291 km2 under 2017.  :o
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.

Wherestheice

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Re: 2018 sea ice area and extent data
« Reply #488 on: April 24, 2018, 08:44:49 AM »
I see a big drop coming sometime in the next few days
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #489 on: April 24, 2018, 09:39:20 AM »
JAXA DATA - 12,803,197 km2(April 23, 2018)

Extent loss has stalled. I've got a déjà vu. Last year interminable speculations on how much below 4 million km2 the 2017 minimum was going to be - and it ended up at nearly 4.5 million km2. There is, on average,  just 10.7 % of the melting done. Early days.
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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #490 on: April 24, 2018, 06:20:54 PM »
JAXA Analysis:

It is possible that 2018 drops more than 54.1K km2 average on the next 11 days, so I do not discard that could continue been the lowest on record. But I see a big probability that the average drop will be more than 20.6K km2. So, I think that -at least- 2018 will be second lowest on record at the end of April.

JAXA Analysis:

As gerontocrat says, extent loss has stalled on 2018. The average daily drop on the last two days is -6.5K km2. Meanwhile, the average drop of 2016 is -77.7K km2 and of 2017 is -52.8K km2.

Will 2018 become the third lowest registered? I do not believe so, at least, not in April. On the following days, 2017 is going to stall so much, that on the beginning of May, the competence for the second or third place will be with 2006.

On the other hand, Will 2018 become the lowest on record? I do not believe so. The drop of 2016 to April 30th is -60.8K km2. Furthermore, to 2018 match 2016 on April 30th, the average daily drop should be 76K km2.

So, from my point of view, 2018 is going to remain on second place, until the beginning of May.
« Last Edit: April 25, 2018, 04:17:04 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.

Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #491 on: April 25, 2018, 05:51:30 AM »
ADS NIPR JAXA, ASI Extent.

April 24th, 2018: 12,794,137 km2, a drop of -9,060 km2.
2018 is the second lowest on record.
2018 is 160,465 km2 above 2016 and 38,713 km2 under 2017.
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: 2018 sea ice area and extent data
« Reply #492 on: April 25, 2018, 10:40:53 AM »
Nothing to add to Juan's posting except the tables but one thought.

Melting (and the reverse) seems to go in waves. My utterly unscientific speculation is that this reflects the relatively warm and relatively cold weather circulating around the polar region. Therefore maybe we are now about to enter another wave of melting as warmth gets into vulnerable areas of the periphery. I have no evidence for this whatsoever.
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uniquorn

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Re: 2018 sea ice area and extent data
« Reply #493 on: April 25, 2018, 06:55:31 PM »
Quote
Melting (and the reverse) seems to go in waves
Your chart clearly shows a (possibly random) wave pattern. Does the area chart show a similar pattern? It may be that the way extent is measured/calculated amplifies the waves.

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #494 on: April 25, 2018, 07:33:56 PM »
Quote
Melting (and the reverse) seems to go in waves
Your chart clearly shows a (possibly random) wave pattern. Does the area chart show a similar pattern? It may be that the way extent is measured/calculated amplifies the waves.

JAXA data is a 2 day average.

NSIDC produce single day figures for total arctic extent, but the graphs on http://nsidc.org/arcticseaicenews/ are, I believe, based on the 5 day trailing average.

NSIDC use a 5 day trailing average for their regional sea area and extent spreadsheets. This smooths out variations in one day changes but makes comparisons of individual days more or less useless.

I try to avoid mixing the two sources (JAXA & NSIDC) as they use different instruments and different algorithms, or mixing area and extent as winds and currents can, for example, spread out sea ice resulting in extent measured higher while area may still drop.

That is why when I do postings on sea-ice data, one has JAXA data and the other will have NSIDC data. Never mix apples with ranges.

My non-scientific speculation will have to stay as a speculation on the JAXA data only.

Note: Over longer periods of time, measures of changes in area and extent  - 2-day,5-day,one day, follow each other pretty closely.
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Re: 2018 sea ice area and extent data
« Reply #495 on: April 25, 2018, 08:22:23 PM »
thank you Gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #496 on: April 25, 2018, 08:41:02 PM »
Quote
Melting (and the reverse) seems to go in waves
Your chart clearly shows a (possibly random) wave pattern. Does the area chart show a similar pattern? It may be that the way extent is measured/calculated amplifies the waves.

Same here - there is a long term trend, and then a short periodicity on a wavelength of a few days that is likely to be the periodicity of weather changes. If someone wants to show me where the data is maybe a .csv, then I'll apply an FFT and maybe something will drop out.

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #497 on: April 25, 2018, 08:50:17 PM »
Quote
Melting (and the reverse) seems to go in waves
Your chart clearly shows a (possibly random) wave pattern. Does the area chart show a similar pattern? It may be that the way extent is measured/calculated amplifies the waves.

Same here - there is a long term trend, and then a short periodicity on a wavelength of a few days that is likely to be the periodicity of weather changes. If someone wants to show me where the data is maybe a .csv, then I'll apply an FFT and maybe something will drop out.

Below the graph on https://ads.nipr.ac.jp/vishop.ver1/vishop-extent.html you will see a download option for a .csv file. It's got the lot.

For NSIDC data go to https://nsidc.org/arcticseaicenews/sea-ice-tools/ for a range of spreadsheets.  The first one " All daily (single day and five-day trailing average) extent values in one file", updated daily has both one day and 5-day extents for the Arctic and Antarctica.

Enjoy.

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Alexander555

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Re: 2018 sea ice area and extent data
« Reply #498 on: April 25, 2018, 08:59:03 PM »
The Bering Sea is a month in advance, and we are close to the lowest extent. Than their has to be a place that has more extent than normal.  I have been looking on Nasa worldview. But the only place where there is more than the years before is west of the Kara Sea, near that long island. All the rest looks the same or less. North of Svalbard is big gap. The Ice in the Okhotsk Sea is almost gone. So where is that extra extent, or has it something to do with that 15 % ice cover.

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Re: 2018 sea ice area and extent data
« Reply #499 on: April 25, 2018, 09:34:40 PM »
The Bering Sea is a month in advance, and we are close to the lowest extent. Than their has to be a place that has more extent than normal.  I have been looking on Nasa worldview. But the only place where there is more than the years before is west of the Kara Sea, near that long island. All the rest looks the same or less. North of Svalbard is big gap. The Ice in the Okhotsk Sea is almost gone. So where is that extra extent, or has it something to do with that 15 % ice cover.
We are not at normal extent, we are far lower than normal, with only the abnormal 2017 and 2016 for company. But the best link for this question is Wipneus' AMSR2 regional page.  https://sites.google.com/site/arcticseaicegraphs/regional
Click on the left-hand chart for extent numbers, with the legend at the bottom. It shows the Barents running high compared to 2016/2017, and Okhotsk as well, while Bering, Baffin and Greenland Sea are lower.