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be cause

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Re: 2019 sea ice area and extent data
« Reply #1700 on: July 17, 2019, 08:35:54 PM »
  Rich , I didn't realise the AMSR2 figures had been refuted .  Does the University of Hamburg know ?

  I was just directing you to the basis of UCM's reference . b.c.

2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

UCMiami

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Re: 2019 sea ice area and extent data
« Reply #1701 on: July 17, 2019, 09:03:59 PM »
Steven and Rich - it would be helpful to see the CAB graph with both the X and Y axis expanded - harder to detect the individual years variations but gives a clearer view of what the 'average' melt season actually looks like. As it is you can see that on July 1 most years are bunched within 100K range and within the next 20 days a significant decrease is evident - if the x access included the range from 0 to 3.2 and the y axis included March through October it would result in very much the same --v-- form that Oren's graph shows with only small variation of where the v begins and ends and much greater variation with it's depth. The scale definitions on Oren's graph are missing and it is from a different data set, but the trajectory of the lines I am sure would match this one.

The scale of these 40 day graphs is useful for exact variation, but it inflates the way we see the variations as does the reduction in the x axis to 33% of actual total area the CAB.

Steven

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Re: 2019 sea ice area and extent data
« Reply #1702 on: July 17, 2019, 10:35:54 PM »
The scale of these 40 day graphs is useful for exact variation, but it inflates the way we see the variations as does the reduction in the x axis to 33% of actual total area the CAB.

The 40-day window seemed appropriate as I was replying to Rich's comment upthread.  Anyway, here is a version for the full melt season.  Click image to enlarge.



For comparison, there are daily updated regional NSIDC graphs on Wipneus' site:

Area: https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc-nt-regional-area-overview.png

Extent: https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc-nt-regional-extent-overview.png

But note that Wipneus uses a different definition of the regions, with the CAB being larger than for the official NSIDC data, as also discussed here.

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #1703 on: July 18, 2019, 05:51:25 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

July 17th, 2019:
     7,323,641 km2, a century drop of -100,459 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.

Killian

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Re: 2019 sea ice area and extent data
« Reply #1704 on: July 18, 2019, 06:05:26 AM »
Very short-term ASIE predictions are really hard.

LOL at myself. Ha...

Quote
Quote
7/17/11 - 7.15M km sq

2011 drops a further 90k and I see no reason for 2019 to keep pace. Looking at what all you good people have to say, winds, temps here and there, there's little to point to strong compaction. Say, 7.35.

EDIT/UPDATE 7/16: 2019 starts from 7.42, not 7.43, so revise to 7.34. (I'd like to increase this drop, but will live or die with the original predictions. Looking at a 190k spread, if so. News around the fora indicates it may decrease, though, or stay the same.)

Edit/Update 7/17: Dropped a full 100k to 7.32. Should've increased it. 2011 leads by 170k.


Fun Fact: Over the next 23 days (Aug 9, end of the GAC effects) 2012 dropped about 103k km/day. Tough to match! Oh, wait: 2018 dropped 100k km/day over the same time frame. Seems '19 ice is worse off than '18... right?

Hmmm...
« Last Edit: July 18, 2019, 06:35:51 AM by Killian »

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1705 on: July 18, 2019, 06:17:06 AM »
JAXA ARCTIC EXTENT :- 7,323,641 km2(July 17, 2019)

After 6 days of well below average extent loss, a day of above average extent loss.
On average, two thirds of extent loss completed.

- Extent is 2nd lowest in the satellite record, 172 k above 2011.
- Extent loss on this day 100 k, 9k more than the average loss on this day of 91 k.
- Extent loss from maximum 6,947 k, 333 k (5.0%) greater than the average of 6,614 k loss from maximum by this day,
- On average 66.9% of the melting season done, with 58 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 4.06 million km2, 3rd lowest in the satellite record , and 0.88 million km2 above the 2012 low of 3.18 million km2.

Other Stuff
Weather
GFS  showing temperature anomalies in the range +1.0 to 0 degrees celsius over the next 10 days. Negative temperature anomalies seem to be mainly in eastern Siberia.

Over the next 5 days it looks like a fairly significant low sits over the central Arctic Ocean north of Central / Eastern Siberia and elsewhere a high sits in the North Atlantic and another high over Greenland. The strongish anticlockwise winds matching but opposite to the normal clockwise movement of the Beaufort Gyre are maintained, starting as strong northerly winds from the CAA and the North Greenland coast. Wind and rain also from the South up Baffin Bay into the CAA at least for the first few days.

GFS suggests that after a few days lows from the North Pacific start to enter the Arctic through the Bering Strait, presumably bringing warmth, moisture and waves.

What all this means for melt is.... ?

Ice Melt Outlook
We are now in the period of maximum daily extent loss that lasts until the end of July and then very gradually declines. Immediate weather outlook suggests a cooler Arctic, but then?


The June volume data persuaded me to drop my minimum guesstimate to below 4 million km2 from exactly 4 million km2. A mistake?
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sja45uk

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Re: 2019 sea ice area and extent data
« Reply #1706 on: July 18, 2019, 01:21:41 PM »
I am confused why you did not include 2011 on the JAXA graphs, when on 17 July it was in first place! It is obvious (to casual inspection) that the JAXA daily extent curve for 2019 shows an offset downwards when compared with 2012. It would have been useful to do a similar visual comparison with the 2011 data.

Shared Humanity

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Re: 2019 sea ice area and extent data
« Reply #1707 on: July 18, 2019, 02:37:53 PM »
5 day average area loss in the CAB jumps WAY up. From 7k to 19k.

Do the math. 19k * 5 = 95k CAB loss in the last 5 days and apparently a huge chunk of that in the last 24 hours.

Why? Where? How? It's all a mystery.

Someone(s) at NSIDC have access to much more granular area data than we do and understand where losses are happening in that gigantic bucket we call "CAB".

I don't see anything unusual for the CAB.  Those losses are normal for this time of year:



If you want to see where exactly the losses are coming from, take a look at the NSIDC sea ice concentration images:

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/images/2019/

 Very normal only when compared to the last decade

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1708 on: July 18, 2019, 03:46:05 PM »
NSIDC Total Area as at 17 July 2019 (5 day trailing average) 5,044,111  km2

Area loss remaining a bit below average.
                        
Total Area         
 5,044,111    km2      
-581,612    km2   <   2010's average.
-665,756    km2   <   2018
-1,326,616 km2   <   2000's average.
         
Total Area Change   -93    k   loss
Peripheral Seas   -14    k   loss
Central Seas__   -61    k   loss
Other Seas___   -18    k   loss
         
Peripheral Seas         
Bering _______    0    k   gain
Baffin  Bay____   -3    k   loss
Greenland____   -9    k   loss
Barents ______   -2    k   loss
         
CAB Seas         
Beaufort_____   -9    k   loss
CAA_________   -5    k   loss
East Siberian__   -13    k   loss
Central Arctic_   -19    k   loss
         
Kara_________   -6    k   loss
Laptev_______   -3    k   loss
Chukchi______   -5    k   loss
         
Other Seas         
Okhotsk______    0    k   gain
St Lawrence___    0    k   gain
Hudson Bay___   -19    k   loss

- Area loss 93 k, 10 k LESS than the 2010's average loss of 103 k on this day.
- Total area Lowest, 296 k LESS than 2016, and 16 k LESS than 2012.

Area loss dipping below average, difference with 2012 narrowing, with 2016 widening.

Other Stuff
Weather
GFS  showing temperature anomalies in the range +1.0 to 0 degrees celsius over the next 10 days. Negative temperature anomalies seem to be mainly in eastern Siberia.

Over the next 5 days it looks like a fairly significant low sits over the central Arctic Ocean north of Central / Eastern Siberia and elsewhere a high sits in the North Atlantic and another high over Greenland. The strongish anticlockwise winds matching but opposite to the normal clockwise movement of the Beaufort Gyre are maintained, starting as strong northerly winds from the CAA and the North Greenland coast. Wind and rain also from the South up Baffin Bay into the CAA at least for the first few days.

GFS suggests that after a few days lows from the North Pacific start to enter the Arctic through the Bering Strait, presumably bringing warmth, moisture and waves. This would be a big change.

What all this means for melt is.... ?

A cliff or not a cliff** See below
We are in the period of maximum daily area loss that lasts until late July.
Overall, Area losses in July to date above average, but trending downwards.

It is definitely was a steep downward slope that as now eased.

The ESS was not a slope, or a cliff. It was a yawning abyss, but has the yawn bottomed out? Pretty much

NSIDC 5 day Area could/would/should/will/will-not continue in pole position for about one week/two weeks/the rest of July/the entire remaining melt season (delete as applicable).
________________________________________________________________________
Extent loss up on this day.
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Rich

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Re: 2019 sea ice area and extent data
« Reply #1709 on: July 18, 2019, 04:48:38 PM »
The CAB area loss rate stays at 19k km2 for the 2nd straight day. Doing what it needs to do for 2019 to maintain a chance for a record minimum.

I'll agree that there is no natural boundary that gives rise to splitting the CAB into sub-buckets, but there is also no natural reason for dividing a day into hours, minutes and seconds. No one argues that we shouldn't have done that.

Like a clock, NSIDC can split up the CAB 360 degree circle into 12 equal sections of 30 degrees each so that we have a better idea where ice area losses are happening and make sense of them. The share of the public interested in that info is pretty small, so I don't expect any progress on that front. I rest my case.

Alphabet Hotel

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Re: 2019 sea ice area and extent data
« Reply #1710 on: July 18, 2019, 05:57:26 PM »
NSIDC daily extent

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #1711 on: July 19, 2019, 05:48:58 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

July 18th, 2019:
     7,189,518 km2, a century drop of -134,123 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 #1712 on: July 19, 2019, 06:38:27 AM »
JAXA ARCTIC EXTENT :- 7,189,518 km2(July 18, 2019)

After 6 days of well below average extent loss, another day of above average extent loss.
On average, more than two thirds of extent loss completed.

- Extent is 2nd lowest in the satellite record, extent is 130 k above 2011.
- Extent loss on this day 134 k, 48 k more than the average loss on this day of 86 k.
- Extent loss from maximum 7,082 k, 382 k (5.7%) greater than the average of 6,700 k loss from maximum by this day,
- On average 67.8% of the melting season done, with 57 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 4.01 million km2, 2nd lowest in the satellite record , and 0.83 million km2 above the 2012 low of 3.18 million km2.

Other Stuff
Weather
GFS  showing temperature anomalies in the range +1.0 to 0 degrees celsius over the next 10 days. Negative temperature anomalies seem to be mainly in eastern Siberia, and later in the forecast period in Western Canada and the CAA.

Over the next few days it looks like a fairly significant low sits over the central Arctic Ocean north of Central / Eastern Siberia and elsewhere a high sits in the North Atlantic and another high over Greenland. The strongish anticlockwise winds matching but opposite to the normal clockwise movement of the Beaufort Gyre are maintained, starting as strong northerly winds from the CAA and the North Greenland coast. Wind and rain also from the South up Baffin Bay into the CAA at least for the first few days.

GFS suggests that after a few days this pattern starts to decay, lows from the North Pacific start to enter the Arctic through the Bering Strait, presumably bringing warmth, moisture and even waves.

What all this means for melt is.... ?

Ice Melt Outlook
We are now in the last two weeks of the period of maximum daily extent loss that lasts until the end of July and then very gradually declines. Immediate weather outlook suggests a cooler Arctic, but then?

The June volume data persuaded me to drop my minimum guesstimate to below 4 million km2 from exactly 4 million km2. A mistake. or not a mistake, or even an underestimate of extent loss to come?
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etienne

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Re: 2019 sea ice area and extent data
« Reply #1713 on: July 19, 2019, 09:31:51 AM »
JAXA ARCTIC EXTENT :- 7,189,518 km2(July 18, 2019)

After 6 days of well below average extent loss, another day of above average extent loss.
On average, more than two thirds of extent loss completed.

- Extent is 2nd lowest in the satellite record, extent is 130 k above 2011.
- Extent loss on this day 134 k, 48 k more than the average loss on this day of 86 k.
- Extent loss from maximum 7,082 k, 382 k (5.7%) greater than the average of 6,700 k loss from maximum by this day,
- On average 67.8% of the melting season done, with 57 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 4.01 million km2, 2nd lowest in the satellite record , and 0.83 million km2 above the 2012 low of 3.18 million km2.

According to these datas :

The 0.83 million km2 above 2012 record with an average melt  (4.01 million km2) means that we need 20% extra melt to reach the 2012 record. It's a lot and will probably not be reached (we are now 5.7% above average), but a second position is not a good news either. 
2012 was breaking all records, also regarding Greenland Melt Extent (http://nsidc.org/greenland-today/ and here https://nsidc.org/greenland-today/greenland-surface-melt-extent-interactive-chart/).

Alison

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Re: 2019 sea ice area and extent data
« Reply #1714 on: July 19, 2019, 12:49:58 PM »
An average melt won’t break records - just like an average 2012 wouldn’t have from here. It takes something exceptional to break records - with seven years of additional CO2 and heat, that something may not need to be quite as exceptional as 2012 - but still exceptional, IMO.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1715 on: July 19, 2019, 01:44:15 PM »
An average melt won’t break records - just like an average 2012 wouldn’t have from here. It takes something exceptional to break records - with seven years of additional CO2 and heat, that something may not need to be quite as exceptional as 2012 - but still exceptional, IMO.
When just an average of the last 10 years melt from now would produce a 2nd lowest extent (and area) it does tell you the ice is in a pretty bad state.

It will only need area loss from now to be above average by 9% to produce a new record area low.

If volume loss from 30 June to minimum is merely average, volume will be lowest in the satellite record by a whopping 10%.

When things look dodgy even in a year that is not exceptional, you know the ice is not looking in good shape..
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1716 on: July 19, 2019, 03:23:22 PM »
NSIDC Total Area as at 18 July 2019 (5 day trailing average) 4,967,682 km2

Area loss remaining a bit below average.
                        
Total Area         
 4,967,682    km2      
-563,885    km2   <   2010's average.
-643,430    km2   <   2018
-1,313,926    km2   <   2000's average.
         
Total Area Change   -76    k   loss
Peripheral Seas   -18    k   loss
Central Seas__   -45    k   loss
Other Seas___   -14    k   loss
         
Peripheral Seas         
Bering _______   -0    k   loss
Baffin  Bay____   -3    k   loss
Greenland____   -11    k   loss
Barents ______   -3    k   loss
         
CAB Seas         
Beaufort_____   -9    k   loss
CAA_________   -6    k   loss
East Siberian__   -12    k   loss
Central Arctic_   -6    k   loss
         
Kara_________   -8    k   loss
Laptev_______    1    k   gain
Chukchi______   -3    k   loss
         
Other Seas         
Okhotsk______   -0    k   loss
St Lawrence___    0    k   gain
Hudson Bay___   -14    k   loss

- Area loss 76 k, 21 k LESS than the 2010's average loss of 97 k on this day.
- Total area Lowest, 290 k LESS than 2016, and 11 k LESS than 2012.

Area loss dipping to well below average, difference with 2012 narrowing, with 2016 widening.

Other Stuff
Weather
GFS  showing temperature anomalies in the range +1.0 to 0 degrees celsius over the next 10 days. Negative temperature anomalies seem to be mainly in eastern Siberia, and later in the forecast period in Western Canada and the CAA.

Over the next few days it looks like a fairly significant low sits over the central Arctic Ocean north of Central / Eastern Siberia and elsewhere a high sits in the North Atlantic and another high over Greenland. The strongish anticlockwise winds matching but opposite to the normal clockwise movement of the Beaufort Gyre are maintained, starting as strong northerly winds from the CAA and the North Greenland coast. Wind and rain also from the South up Baffin Bay into the CAA at least for the first few days.

GFS suggests that after a few days this pattern starts to decay, lows from the North Pacific start to enter the Arctic through the Bering Strait, presumably bringing warmth, moisture and even waves.

What all this means for melt is.... ?

A cliff or not a cliff** See below
We are in the period of maximum daily area loss that lasts until late July.
Overall, Area losses in July to date above average, but trending downwards.

It is definitely was a steep downward slope that has now eased.

The ESS was not a slope, or a cliff. It was a yawning abyss, but has the yawn bottomed out? Pretty much

NSIDC 5 day Area could/would/should/will/will-not continue in pole position for about one week/two weeks/the rest of July/the entire remaining melt season (delete as applicable).
________________________________________________________________________
Extent loss up by a lot for a second day.
"Para a Causa do Povo a Luta Continua!"
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Killian

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Re: 2019 sea ice area and extent data
« Reply #1717 on: July 19, 2019, 05:07:44 PM »
Quote
7/18/11 - 7.06M km sq.

Same here... 7.26....

Edit/Update 7/17: I called 80k. Don't think it will be that low. While winds overall seem to be suggesting expansion, there's some strong stuff forecast over Siberia that could spread the ice.

Sticking w/ previous 80k call: 7.24, +180k relative to '11.

Revising for current conditions: 7.22, or 100k drop, +160k to '11.

Surprise! -130k km sq! 7.19M km sq, or as gerontocrat says, 130k km sq more extent than 2011. Definitely *not* at or over +200k.

Looking to the 19th, then...

Quote
Quote
7/19/11 - 7.00M km sq.

...and here...  7.2. Winds really look dominant in all the right areas to either expand where there's room or toward compaction where there's no room to compact.

Windy seems to indicate compacting going on right now in most areas with winds mostly offshore and parallel to shore, and those going toward shore that might increase extent are in areas where there's nowhere for the ice to go. Sitting at 7.19M and a further drop of 60k to the 19th in 2011, thus a deficit of 190k for '19 to make up, 2019 will not be catching 2011 on the 19th. I think it will, however, cut the differential nearly in half. A drop of 110 - 130k tomorrow, specifically 110, but I can easily see higher, gets 2019 to 7,080k km sq for the 19th.

Longer term, the talk of dipoles and popcorn (my term) ice and whatnot seems to indicate 2019 will likely overtake 2011 before the 25th given there may be a deficit or only 80k or less after the data for the 19th comes in. If so, and if the lows, storms and dipoles stick around a bit and/or are strong enough to shove significant ice down Fram's throat, the 25th might again be looking veeeery interesting.

No more 5-days. The weather changes too drastically. Will stick to 1~3 day prognostications henceforth.

Pragma

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Re: 2019 sea ice area and extent data
« Reply #1718 on: July 19, 2019, 05:23:54 PM »
People!

As had been said many times, this is a data thread, not a discussion thread.

Dissertations do not belong here; they are clutter and just lower the signal to noise ratio.

Please move any discussion of the data to the melting season thread, (or whatever is current at the time).

Thanks for your cooperation.

Stephan

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Re: 2019 sea ice area and extent data
« Reply #1719 on: July 19, 2019, 05:33:34 PM »
Analysis of gerontocrat's sea ice area table "relative area wise" 1.-18.7.2019:
Losses of 63-75% occurred in Hudson, Baffin, and Kara. All three of them should be almost ice free by mid August 2019.
Losses of 44-56% occurred in Barents, Laptev, Chukchi, and ESS (and further retreat expected)
A much smaller loss (26%) in Beaufort
Only little area reductions happened in Grønland Sea (19%), CAA (14%) and finally CAB (7%)
Seas with almost no ice (if there is any) were not analysed.


FishOutofWater

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Re: 2019 sea ice area and extent data
« Reply #1720 on: July 19, 2019, 06:15:12 PM »
The "other stuff" part of Gernontocrat's posts are not data. They are a discussion section concerning GFS ten day forecasts. Intentionally, or unintentionally, they invite discussion.

Other Stuff
Weather
GFS  showing temperature anomalies in the range +1.0 to 0 degrees celsius over the next 10 days. Negative temperature anomalies seem to be mainly in eastern Siberia, and later in the forecast period in Western Canada and the CAA.

Over the next few days it looks like a fairly significant low sits over the central Arctic Ocean north of Central / Eastern Siberia and elsewhere a high sits in the North Atlantic and another high over Greenland. The strongish anticlockwise winds matching but opposite to the normal clockwise movement of the Beaufort Gyre are maintained, starting as strong northerly winds from the CAA and the North Greenland coast. Wind and rain also from the South up Baffin Bay into the CAA at least for the first few days.

GFS suggests that after a few days this pattern starts to decay, lows from the North Pacific start to enter the Arctic through the Bering Strait, presumably bringing warmth, moisture and even waves.

What all this means for melt is.... ?


I appreciate the detailed accounting that Gerontocrat does. It's an amazing effort that clearly involves many hours of work a week. However, sometimes I disagree with his interpretations of the weather models in the "other stuff" section. If he is going to include "other stuff" replies concerning "other stuff" need to go here to maintain clarity to the reader.

That said, melting season discussion should go to the melting season threads, not here.

Shared Humanity

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Re: 2019 sea ice area and extent data
« Reply #1721 on: July 19, 2019, 07:40:38 PM »
FOW...

This point could have been made far more succinctly

Alphabet Hotel

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Re: 2019 sea ice area and extent data
« Reply #1722 on: July 19, 2019, 09:07:05 PM »
The server with the NSIDC daily extent data is offline. Is there another source for this?

Killian

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Re: 2019 sea ice area and extent data
« Reply #1723 on: July 20, 2019, 04:23:34 AM »
People!

As had been said many times, this is a data thread, not a discussion thread.

Dissertations do not belong here; they are clutter and just lower the signal to noise ratio.

Please move any discussion of the data to the melting season thread, (or whatever is current at the time).

Thanks for your cooperation.

Feedback, to be of use, must be 1. specific, 2. actionable, 3. clear.

1. Who? What? Why? Etc.
2. What to do? (This was clear.)
3. Who should do what? And what is not acceptable. In this case, what equals discussion vs. description?

If discussing data, there will be some bleed-over with discussion of what happens and why, but does that equal the "season" if discussing understanding data over the stretch of few days? Trying to understand data, micro, seems appropriate here. Trying to understand the longer season seems, yes, should be on the other thread.

Clarification?

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #1724 on: July 20, 2019, 05:43:13 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

July 19th, 2019:
     7,069,820 km2, a century drop of -119,698 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.

Killian

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Re: 2019 sea ice area and extent data
« Reply #1725 on: July 20, 2019, 07:54:10 AM »
7/18/11 was 7.06M km --> 7/19/11 - 7.00M km sq.

7/18/19 was 7.19M km --> 7/19/19 dropped 120k to 7.07.

Predicted -110k to 7.08M km with range of -110k - 130k.

Five days ago I thought we'd be at 7.2M. Oops.

Note to complainant:

1. Are you an admin? This affects future actions, so please reply.
1b. Neven has not complained even though I have discussed these things in relation to other points across at least two threads. Neven is certainly not patient with forum resources being wasted, yet he said nothing. If he does when he returns, then clearly...
1c. If you are an admin, then clearly...

2. When asked for clarification, it is rude to not clarify and merely make stentorious demands.

3. This thread is about statistics. The other thread is about the developing season. My purpose in doing this is to understand the usefulness of the statistics, not develop a theory of this season. I have already determined through this trial and error that anything over 2 or 3 days is extremely unlikely to be more than randomly within an acceptable range of error. To my mind, that's a great outcome for such a short period of analysis. The question remains, can short-term predictions be made with enough certitude to bother with them?

There has been considerable discussion about the usefulness of short- and long-term models. I am exploring that.

4. Gerontocrat offers forward-looking analysis with his numbers. How is this different?

Cheers

binntho

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Re: 2019 sea ice area and extent data
« Reply #1726 on: July 20, 2019, 08:09:00 AM »
So should we all start posting our "wet finger in the air" guesses in order to find out that guesses are not really very reliable predictors for the future? Or posting that we are currently thinking about something or other and just posting this post to mark that this is when we started to think the things that we started thinking about at that time?

Methinks that sort of thing belongs here

oren

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Re: 2019 sea ice area and extent data
« Reply #1727 on: July 20, 2019, 08:49:11 AM »
This thread should be about actual area and extent data. The ratio of predictions and verbose discussions to actual data should be low.
Killian I too feel your recent posts contain lots of words and (trial) predictions with a high ratio to data, and should go to the thread recommended by binntho.
In general, this thread has been suffering recently from too many discussions. It should be the 3 daily posts by JCG and G., a bit of additional recurring and one-time data analysis/charts, and the occasional few short lines by someone commenting on the data.
(Yes this post contributes to the mayhem, which is why I waited a while to write it, and I will not follow up on it).
Note: I also think gerontocrat's posts would be better with less prediction discussions, especially as a lot of that is copied from day to day. I am ashamed to admit I normally scroll through the words. But Gerontocrat has earned the right for some uncriticized chatter thanks to his relentless data updates, both covering diverse parts of the data and doing so on a recurring basis. So envy him not.

pauldry600

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Re: 2019 sea ice area and extent data
« Reply #1728 on: July 20, 2019, 08:50:17 AM »
It looks like the final number will settle around 4m. But im just curious to know are we now about to enter a decade of finishes in the 3s and does that mean we only have 30 years left till zero sea ice

Killian

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Re: 2019 sea ice area and extent data
« Reply #1729 on: July 20, 2019, 09:17:28 AM »
7/19/2019 stands at 7.07M km sq.
7/19/2011 stands at 7.00M km sq.

7/20/2011 fell 50k km sq to 6.95M km sq.
7/20/2019 will need -120k km sq to equal that.

We've seen -100k, -130k and -120k losses over three days. As far as I can tell, we have compaction dominating north of NA and eastern Siberia, and expansion dominating north of western Siberia. Compaction dominant as Fram, Svalbard, et al. Temp anomalies are warm around the edges, but the mean below average. The system over the Beaufort is moving towards the central CAB. Mixing? Seems odd we've lost 350k kms over the last three days.

Meh... call it -100k to 6.97 and +20k to 2011. Anything from -80k ~ -120k will not surprise. What dominates conditions on any given day is a puzzle...

Cheers


Killian

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Re: 2019 sea ice area and extent data
« Reply #1730 on: July 20, 2019, 09:28:14 AM »
I suspect that board criticism would result in Neven asking you to take your predictions elsewhere, but he"s not here and we don't necessarily want to burden him with being the referee all the time even when he is here.

In the spirit of de-clutter and no meta discussion, I will  remove this post shortly.

Clearly communicated, without [<-- edit] overbearing demeanor. Thanks.
« Last Edit: July 21, 2019, 07:11:28 AM by Killian »

Killian

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Re: 2019 sea ice area and extent data
« Reply #1731 on: July 20, 2019, 09:36:34 AM »
Killian I too feel your recent posts contain lots of words and (trial) predictions with a high ratio to data, and should go to the thread recommended by binntho.

Data without context is just numbers, and absolutely nobody needs anybody else to post those numbers just for the numbers. NSIDC posts them, JAXA posts them, etc.

Odd, to me. Still, not my house.

Appreciate the elucidation. Disagree with the specific suggestion. Will meditate on it all prior to my next post, if any.

Cheers

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1732 on: July 20, 2019, 10:12:02 AM »
JAXA ARCTIC EXTENT :- 7,069,820 km2(July 19, 2019)

July extent loss to date still above average overall.
On average, more than two thirds of extent loss completed.

- Extent is 2nd lowest in the satellite record, extent is 75 k above 2011.
- Extent loss on this day 120 k, 41 k more than the average loss on this day of 79 k.
- Extent loss from maximum 7,201 k, 422 k (6.2%) greater than the average of 6,779 k loss from maximum by this day,
- On average 68.6% of the melting season done, with 56 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.

Other Stuff
Weather
Current conditions:  There is a lot of weather in the Arctic.
Future conditions:  There will be a lot more weather in the Arctic.

What all this means for melt is.... ?

Ice Melt Outlook The peak days of daily melt are  past. From now to minimum, on average daily extent loss will initially slowly reduce, this reduction in daily loss gradually increasing on the approach to minimum. 

The June volume data persuaded me to drop my minimum guesstimate to below 4 million km2 from exactly 4 million km2. A mistake. or not a mistake, or even an underestimate of extent loss to come?
______________________________________________________________
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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)

Sterks

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Re: 2019 sea ice area and extent data
« Reply #1733 on: July 20, 2019, 10:23:15 AM »
As Neven said in his blog, it shouldn’t but it does

binntho

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Re: 2019 sea ice area and extent data
« Reply #1734 on: July 20, 2019, 12:00:44 PM »
Other Stuff
Weather
Current conditions:  There is a lot of weather in the Arctic.
Future conditions:  There will be a lot more weather in the Arctic.

What all this means for melt is.... ?

Enuff said ...

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1735 on: July 20, 2019, 04:15:50 PM »
NSIDC Total Area as at 19 July 2019 (5 day trailing average)  4,885,824 km2

Area loss remaining a bit below average.
                        
Total Area         
 4,885,824    km2      
-553,535    km2   <   2010's average.
-622,906    km2   <   2018
-1,308,286    km2   <   2000's average.
         
Total Area Change   -82    k   loss
Peripheral Seas   -17    k   loss
Central Seas__   -54    k   loss
Other Seas___   -11    k   loss
         
Peripheral Seas         
Bering _______   -0    k   loss
Baffin  Bay____   -4    k   loss
Greenland____   -10    k   loss
Barents ______   -3    k   loss
         
CAB Seas         
Beaufort_____   -7    k   loss
CAA_________   -7    k   loss
East Siberian__   -16    k   loss
Central Arctic_   -9    k   loss
         
Kara_________   -11    k   loss
Laptev_______    1    k   gain
Chukchi______   -5    k   loss
         
Other Seas         
Okhotsk______   -0    k   loss
St Lawrence___   -0    k   loss
Hudson Bay___   -11    k   loss

- Area loss 82 k, 12 k LESS than the 2010's average loss of 94 k on this day.
- Total area Lowest, 304 k LESS than 2016, and 6 k LESS than 2012.

Area loss remains below average, difference with 2012 narrowing, with 2016 widening.

Other Stuff
Weather Due to unforeseen circumstances....
_______________________________________________________
Weather
by
Ambrose Bierce

Once I dipt into the future far as human eye could see,
And I saw the Chief Forecaster, dead as any one can be--
Dead and damned and shut in Hades as a liar from his birth,
With a record of unreason seldome paralleled on earth.

While I looked he reared him solemnly, that incandescent youth,
From the coals that he'd preferred to the advantages of truth.
He cast his eyes about him and above him; then he wrote
On a slab of thin asbestos what I venture here to quote--
For I read it in the rose-light of the everlasting glow:
'Cloudy; variable winds, with local showers; cooler; snow.'
_________________________________________________

What all this means for melt is.... ?

Oulook
We are in the period of maximum daily area loss that lasts until late July, but is already gently sliding down. Overall, Area losses in July to date above average, but currently trending downwards.

It definitely was a steep downward slope that has now eased.

NSIDC 5 day Area could/would/should/will/will-not continue in pole position for about one week/two weeks/the rest of July/the entire remaining melt season (delete as applicable).
________________________________________________________________________
"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)

Rich

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Re: 2019 sea ice area and extent data
« Reply #1736 on: July 20, 2019, 05:43:24 PM »
CAB now < 2.7m km2, 12 days after going under 2.8m.

Need 100k per week now to hang with 2012. Slipping behind. I think I've reinforced the CAB enough.. no need for daily reminder going forward.

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #1737 on: July 21, 2019, 05:43:08 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

July 20th, 2019:
     6,975,962 km2, a drop of -93,858 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 #1738 on: July 21, 2019, 10:45:38 AM »
JAXA ARCTIC EXTENT :- 6,975,962 km2(July 20, 2019)

July extent loss to date still above average overall.
On average, more than two thirds of extent loss completed.

- Extent is 2nd lowest in the satellite record, extent is 24 k above 2011.
- Extent loss on this day 94 k, 4 k more than the average loss on this day of 90 k.
- Extent loss from maximum 7,295 k, 426 k (6.2%) greater than the average of 6,869 k loss from maximum by this day,
- On average 69.5% of the melting season done, with 55 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 3.96 million km2, 2nd lowest in the satellite record, and 0.78 million km2 above the 2012 low of 3.18 million km2.

Ice Melt Outlook The peak days of daily melt are  past. From now to minimum, on average daily extent loss will initially slowly reduce, this reduction in daily loss gradually increasing on the approach to minimum. 

The June volume data persuaded me to drop my minimum guesstimate to below 4 million km2 from exactly 4 million km2. A mistake, or not a mistake, or even an underestimate of melt to come? That will depend on the future weather.
______________________________________________________________
"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 #1739 on: July 21, 2019, 03:17:07 PM »
NSIDC Total Area as at 20 July 2019 (5 day trailing average)  4,798,458 km2

Area loss remaining a bit below average.
                        
Total Area         
 4,798,458    km2      
-544,869    km2   <   2010's average.
-609,365    km2   <   2018
-1,313,904    km2   <   2000's average.
         
Total Area Change   -87    k   loss
Peripheral Seas   -18    k   loss
Central Seas__   -60    k   loss
Other Seas___   -8    k   loss
         
Peripheral Seas         
Bering _______    0    k   gain
Baffin  Bay____   -5    k   loss
Greenland____   -11    k   loss
Barents ______   -3    k   loss
         
CAB Seas         
Beaufort_____   -8    k   loss
CAA_________   -5    k   loss
East Siberian__   -15    k   loss
Central Arctic_   -15    k   loss
         
Kara_________   -8    k   loss
Laptev_______   -4    k   loss
Chukchi______   -6    k   loss
         
Other Seas         
Okhotsk______    0    k   gain
St Lawrence___   -0    k   loss
Hudson Bay___   -8    k   loss

- Area loss 87 k, 5 k LESS than the 2010's average loss of 92 k on this day.
- Total area 2nd Lowest, 313 k LESS than 2016, and 4 k MORE than 2012.

Area loss remains just below average, 2012 now lowest by a smidgeon, difference with with 2016 widening.

Other Stuff
On July 31, daylight hours at the North Pole will be more than one hour less than today.

What all this means for melt is.... ?

Oulook
We are in the period of maximum daily area loss that  is already gently sliding down. Overall, Area losses in July to date above average, but currently trending a trifle downwards.

It definitely was a steep downward slope that has now eased.

NSIDC 5 day Area did not continue in pole position for about one week/two weeks/the rest of July/the entire remaining melt season.
________________________________________________________________________
NSIDC daily extent loss just 46k on this 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)

Steven

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Re: 2019 sea ice area and extent data
« Reply #1740 on: July 21, 2019, 03:26:32 PM »
NSIDC daily area is currently very close to 2012:



(Note: data from Wipneus.  He uses leap year corrections for the anomaly data.)

Steerpike

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Re: 2019 sea ice area and extent data
« Reply #1741 on: July 21, 2019, 03:27:51 PM »


On July 31, daylight hours at the North Pole will be more than one hour less than today.



Surely the North Pole receives 24 hours' daylight until the equinox, then switches to zero?
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1742 on: July 21, 2019, 03:37:02 PM »
Somewhat earlier in the melting season there was much about how the central seas of the Arctic were melting at an enormous rate. Attached is an analysis in my JAXA sea ice extent format of where we are on sea ice area of the 7 Central Seas - Tealight's "High Arctic".

The analysis is that area is 2nd lowest, average remaining melt would give a minimum of third lowest.
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1743 on: July 21, 2019, 03:50:04 PM »
On July 31, daylight hours at the North Pole will be more than one hour less than today.
Surely the North Pole receives 24 hours' daylight until the equinox, then switches to zero?
Correct - it was a bad joke - North Pole, Alaska (yes, it does exist).

The point is that it is one month after the solstice - in the very High Arctic summer is almost gone and a very brief fall is about to commence.
"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)

sja45uk

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Re: 2019 sea ice area and extent data
« Reply #1744 on: July 21, 2019, 04:45:23 PM »
JAXA ARCTIC EXTENT :- 6,975,962 km2(July 20, 2019)

The Perils of Projections.
Average remaining melt would give a minimum of 3.96 million km2, 2nd lowest in the satellite record, and 0.78 million km2 above the 2012 low of 3.18 million km2.
______________________________________________________________

I am not sure that I see the value in doing calculations with decadal averages in a steadily warming world. It seems that they provide data that is closer to the minimum that we can expect rather than the most likely data. When I look at the four decadal averages they are clearly stacked in decade order and the offset between each decade and the previous one seems to be increasing. In addition, the gap between adjacent averages seems to widen until the minimum sea ice point is reached. I assume this is well recognized, but the implications only just struck me and I felt than I must comment to check that my observations are correct.

Alphabet Hotel

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Re: 2019 sea ice area and extent data
« Reply #1745 on: July 21, 2019, 04:58:54 PM »
NSIDC daily extent

Starting on the 18th, the daily numbers became unavailable.
Below the dark black line, daily numbers are calculated from the five-day averages.
For example, the formula used for cell D11619 is =5*E11619-SUM(D11615:D11618)

Steven

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Re: 2019 sea ice area and extent data
« Reply #1746 on: July 21, 2019, 05:05:47 PM »
Starting on the 18th, the daily numbers became unavailable.

The daily numbers for NSIDC extent are still available here:

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/

Alphabet Hotel

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Re: 2019 sea ice area and extent data
« Reply #1747 on: July 21, 2019, 05:19:38 PM »
Starting on the 18th, the daily numbers became unavailable.

The daily numbers for NSIDC extent are still available here:

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/

That link never opens for me and eventually times out. The server appears to be offline.

SteveMDFP

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Re: 2019 sea ice area and extent data
« Reply #1748 on: July 21, 2019, 05:33:25 PM »
Starting on the 18th, the daily numbers became unavailable.

The daily numbers for NSIDC extent are still available here:

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/

That link never opens for me and eventually times out. The server appears to be offline.
Link works fine for me (Win 7 OS, Opera browser).  You might try a different browser, or a true FTP client, like FileZilla.
« Last Edit: July 21, 2019, 05:48:53 PM by SteveMDFP »

Steven

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Re: 2019 sea ice area and extent data
« Reply #1749 on: July 21, 2019, 05:42:08 PM »
That link never opens for me and eventually times out. The server appears to be offline.

If you cannot access the FTP data, alternatively you can get the daily NSIDC extent numbers from Wipneus' site:

https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_arc_nt_main.txt