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zufall

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Re: 2018 sea ice area and extent data
« Reply #1750 on: September 24, 2018, 08:23:12 AM »
https://ads.nipr.ac.jp/vishop/#/extent

Sep 23 extent: 4,535,587 km², up 50,333 km².

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1751 on: September 24, 2018, 10:18:55 AM »
JAXA ARCTIC EXTENT 4,535,587 km2(September 23, 2018)

TABLES NOW ASSUME MINIMUM WAS ON 21 SEPTEMBER

Just to add to Juan's post that did not happen today -

Extent is now -
- 97 k  (2.1 %) below the 2010's average extent on this date,
- 166 k (3.6 %) below 2017 on this date.
- the average (10 years) INCREASE in extent from minimum on this date was 213 k greater than the 2018-19 freezing season to date.
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Hautbois

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Re: 2018 sea ice area and extent data
« Reply #1752 on: September 24, 2018, 11:07:01 PM »
Update of my chart. I could attempt to mix metaphors about running backs and fat ladies, but it's probably best that I don't.

Neven

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Re: 2018 sea ice area and extent data
« Reply #1753 on: September 25, 2018, 07:25:09 AM »
Thanks for the update, Hautbois. One stupid question, that you've probably already answered: I thought JAXA data started in 2002 (AMSR-E), buit your chart has minimum dates well before that. How come?

Another uptick of 66K for JAXA SIE, that's almost 150K above the preliminary minimum. Some relatively extreme weather coming up, so let's see if it stands.
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Hautbois

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Re: 2018 sea ice area and extent data
« Reply #1754 on: September 25, 2018, 09:22:38 AM »
Neven: strangely, it seems there are 2 CSV files on extent downloadable from the NIPR website. From your sea ice graphs page, the link in the top right box opens a CSV file that has decadal averages and daily from 2002, as you say. 
The file is called plot_extent_n_v2

But clicking on the JAXA graph itself brings you to here
https://ads.nipr.ac.jp/vishop/#/extent/&time=2018-09-23%2000:00:00
and at the bottom of that page is a link to a CSV file which has daily data for January 14th 1988 onwards.
This file is called vishop_extent_graph.

Both files have the same daily extent numbers so they appear to be showing the same thing.




gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1755 on: September 25, 2018, 09:59:17 AM »
Neven: strangely, it seems there are 2 CSV files on extent downloadable from the NIPR website. From your sea ice graphs page, the link in the top right box opens a CSV file that has decadal averages and daily from 2002, as you say. 
The file is called plot_extent_n_v2

But clicking on the JAXA graph itself brings you to here
https://ads.nipr.ac.jp/vishop/#/extent/&time=2018-09-23%2000:00:00
and at the bottom of that page is a link to a CSV file which has daily data for January 14th 1988 onwards.
This file is called vishop_extent_graph.

Both files have the same daily extent numbers so they appear to be showing the same thing.
JAXA is running two websites for the sea ice data,

https://ads.nipr.ac.jp/vishop.ver1/vishop-extent.html - the original one, linked to data from 2002 and just averages for 1980s, 90's and 00s

https://ads.nipr.ac.jp/vishop/#/monitor - the 2nd one they implemented in 2012. This is linked to data from 1979 mirroring the NSIDC spreadsheets.  It also has more options on the graphs, including graphs for Global Sea Ice..

I am still mostly using the first version as the days extent is shown on the graph - dead easy to copy and put into me spreadsheet - no need to download the .csv files every day.
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Rob Dekker

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Re: 2018 sea ice area and extent data
« Reply #1756 on: September 25, 2018, 10:03:12 AM »
Thanks for the update, Hautbois. One stupid question, that you've probably already answered: I thought JAXA data started in 2002 (AMSR-E), buit your chart has minimum dates well before that. How come?

JAXA is pretty clear :
https://ads.nipr.ac.jp/vishop/#/extent

Method for calculating sea-ice extent

The sea-ice extent is calculated as the areal sum of sea ice covering the ocean where sea-ice concentration (SIC) exceeds a threshold (15% for AMSR-E). SICs are derived from various satellite-borne passive microwave radiometer (PMR) sensors using the algorithm developed and provided by Dr. Comiso of NASA GSFC through a cooperative relationship between NASA and JAXA. The following sensor's data were used;
•   Jan. 1980 ~ Jul. 1987   :   SMMR
•   Jul. 1987 ~ Jun. 2002   :   SSM/I
•   Jun. 2002 ~ Oct. 2011   :   AMSR-E
•   Oct. 2011 ~ Jul. 2012   :   WindSat
•   Jul. 2012 ~ the present   :   AMSR2
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1757 on: September 25, 2018, 10:09:09 AM »
JAXA ARCTIC EXTENT 4,602,216 km2(September 24, 2018)

TABLES NOW ASSUME MINIMUM WAS ON 21 SEPTEMBER

Just to add to Juan's post that did not happen today -

- Extent increase 67k (previous days 53k, 28k) means extent is now -
- 79 k  (1.7 %) below the 2010's average extent on this date,
- 102 k (2.2 %) below 2017 on this date.
- freezing to date from minimum is 187k less than the 10 year average.
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Neven

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Re: 2018 sea ice area and extent data
« Reply #1758 on: September 25, 2018, 10:10:41 AM »
Thanks for the answers. I had forgotten about this.
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E. Smith

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1759 on: September 25, 2018, 03:56:23 PM »
NSIDC Total Area as at 24 September (5 day trailing average) =  3,366,713 km2

Slow area gain, so area now 14k less than 2017 on this day.

Total Area GAIN 15 k ,

Central Seas GAIN      7 k,                                 
Peripheral Seas gain    8 k,
Other Seas loss           0 k, all seas <5% of max.

Chukchi Sea loss 0 k, area 5.0 k[/b], < 5% of max.
East Siberian Sea (ESS) loss 0.5 k , area 92.5 k.

Freezing looks like it has taken hold. Attention switches to the pace of that freezing.
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zufall

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Re: 2018 sea ice area and extent data
« Reply #1760 on: September 25, 2018, 07:08:01 PM »
This long-time lurker wants to say thank you to all the contributors here! I've been visiting this site almost daily for 3 years now. Surely will return tomorrow. :)

Stephan

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Re: 2018 sea ice area and extent data
« Reply #1761 on: September 25, 2018, 07:08:01 PM »
It seems like the ice area reduction in Chukchi and in ESS are coming to an end. Nevertheless, the relative reduction during the last week was remarkable.
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zufall

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Re: 2018 sea ice area and extent data
« Reply #1762 on: September 25, 2018, 07:08:24 PM »
I've been close to posting this 3 times, but each time there came another downturn. However, now the total area of the "periphery + other" (I mean all but the 4 central seas) really seems to have passed its minimum. It has increased slowly but steadily to 164k km² after reaching the minimum of 145k km² on 17 September.

Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #1763 on: September 26, 2018, 06:00:34 AM »
[ADS-NIPR-JAXA] ASI Extent.

September 25th, 2018: 4,660,401 km2, an increase of  58,185 km2.
On this day, 2018 is the 4th lowest on record.
There is a total increase of 203,149 km2 since the minimum.

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 #1764 on: September 26, 2018, 04:49:47 PM »
JAXA ARCTIC EXTENT 4,660,401 km2(September 25, 2018)

2018 MINIMUM WAS ON 21 SEPTEMBER

Just to add to Juan's post that did not happen today -

Strong extent increase 58k, (previous days 67k 53k 28k) means extent is now -
- 69 k  (1.5 %) below the 2010's average extent on this date,
- 95 k (2.0 %) below 2017 on this date.
- freezing to date from minimum is 171k less than the 10 year average.

I thought Arctic temperatures and SSTS would slow refreeze. Oh well.
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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #1765 on: September 27, 2018, 05:56:47 AM »
[ADS-NIPR-JAXA] ASI Extent.

September 26th, 2018: 4,684,212 km2, an increase of 23,811 km2.
2018 is the 4th 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

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Re: 2018 sea ice area and extent data
« Reply #1766 on: September 27, 2018, 10:33:52 AM »
JAXA ARCTIC EXTENT 4,684,212 km2(September 26, 2018)

2018 MINIMUM WAS ON 21 SEPTEMBER

Just to add to Juan's post that did happen today -

- Weak extent increase 28k, (previous days 58k 67k 53k 28k),
- Extent 92 k  (2.0 %) below the 2010's average extent on this date,
- Extent 156 k (3.3 %) below 2017 on this date.
- freezing to date from minimum is 195k (46%) less than the 10 year average.

I thought Arctic temperatures and SSTS would slow the refreeze. Maybe from now?
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1767 on: September 27, 2018, 02:18:36 PM »
NSIDC Total Area as at 26 September (5 day trailing average) =  3,398,973 km2

Slow area gain, so area now 87k less than 2017 on this day.

Total Area GAIN 17 k ,

Central Seas GAIN      7 k,                                 
Peripheral Seas gain    11 k, just about all in the Greenland Sea
Other Seas loss           0 k, all seas <5% of max.


East Siberian Sea (ESS) gain 9 k , 6 k the day before.
Central Arctic Sea          loss  14k, 9 k the day before. See image (from 26th Sept) re warmth pushing polewards in the Atlantic front.

Freezing looks like it has taken hold. Attention switches to the pace of that freezing and where it is happening.
"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 #1768 on: September 28, 2018, 05:47:11 AM »
[ADS-NIPR-JAXA] ASI Extent.

September 27th, 2018: 4,702,933 km2, an increase of 18,721 km2.
Now, 2018 change to become the 3rd 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

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Re: 2018 sea ice area and extent data
« Reply #1769 on: September 28, 2018, 09:21:13 AM »
JAXA ARCTIC EXTENT 4,702,933 km2(September 27, 2018)

2018 MINIMUM WAS ON 21 SEPTEMBER

Just to add to Juan's post that did happen today -

- Weak extent increase 19k,
- Extent is 136 k  (2.9 %) below the 2010's average extent on this date,
- Extent is 186 k (4.0 %) below 2017 on this date.
- freezing to date from minimum is 240k (49%) less than the 10 year average.

On average , extent at 27th September is 205k ABOVE extent on August 31. In contrast, extent on 27 September 2018 is 39k BELOW extent on Aug 31 2018.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1770 on: September 28, 2018, 02:28:40 PM »
NSIDC Total Area as at 27 September (5 day trailing average) =  3,418,222 km2

Slow area gain, so area now 131k less than 2017 on this day.

Total Area gain          19 k ,

Central Seas GAIN      5 k,                                 
Peripheral Seas gain   15 k, just about all in the Greenland Sea
Other Seas loss           0 k, all seas <5% of max.

Greenland Sea gain 13k
Canadian Archipelago gain    13 k
East Siberian Sea (ESS) gain 13 k ,
Central Arctic Sea          loss 25 k, 14 k the day before. warmth pushing polewards in the Atlantic front.

Freezing looks like it has taken hold. Attention switches to the pace of that freezing and where it is happening.

Note:-  Daily Extent went up by 99k on this day.
« Last Edit: September 28, 2018, 06:26:10 PM by gerontocrat »
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Pmt111500

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Re: 2018 sea ice area and extent data
« Reply #1771 on: September 28, 2018, 05:29:02 PM »
[Q]Slow area gain, so area now 131k less than 2017 on this day[/Q]
Ambivalent season continues.

Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #1772 on: September 29, 2018, 06:07:34 AM »
[ADS-NIPR-JAXA] ASI Extent.

September 28th, 2018: 4,713,998 km2, an increase of 11,065 km2.
2018 is the 3rd 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

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Re: 2018 sea ice area and extent data
« Reply #1773 on: September 29, 2018, 08:58:15 AM »
JAXA ARCTIC EXTENT 4,713,998 km2(September 28, 2018)

Just to add to Juan's post that did happen today -

- Weak extent increase 11k,
- Extent is 188 k  (4.0 %) below the 2010's average extent on this date,
- Extent is 283 k (6.0 %) below 2017 on this date.
- freezing to date from minimum is 283k (52.5%) less than the 10 year average.

The table of differences in extent also shows how much 2007 and 2012 remain outliers in the record.

On average , extent at 28th September is 260k ABOVE extent on August 31. In contrast, extent on 28 September 2018 is 28k BELOW extent on Aug 31 2018.
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1774 on: September 29, 2018, 02:43:20 PM »
NSIDC Total Area as at 28 September (5 day trailing average) =  3,428,862 km2

Slow area gain, so area now 181k less than 2017 on this day.

Total Area gain          11 k ,

Central Seas LOSS      5 k,                                 
Peripheral Seas gain   15 k, just about all in the Greenland Sea
Other Seas loss           0 k, all seas <5% of max.

Greenland Sea          gain     15k
Canadian Archipelago gain    14 k
East Siberian Sea (ESS) gain 15 k ,
Central Arctic Sea          loss  33 k, 25 k & 14 k the days before. warmth pushing polewards in the Atlantic front.

Freezing looks like it has taken hold. Attention switches to the pace of that freezing and where it is happening.

Note:-  Daily Extent went up by only 10k on this day after gain of 99k the day before.
« Last Edit: September 29, 2018, 02:49:57 PM by gerontocrat »
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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #1775 on: September 30, 2018, 05:37:20 AM »
[ADS-NIPR-JAXA] ASI Extent.

September 29th, 2018: 4,729,615 km2, an increase of 15,617 km2.
2018 is the 3rd 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

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Re: 2018 sea ice area and extent data
« Reply #1776 on: September 30, 2018, 10:14:18 AM »
JAXA ARCTIC EXTENT 4,729,615 km2(September 29, 2018)

Just to add to Juan's post  -

- Weak extent increase 16k,
- Extent is 216 k  (4.6 %) below the 2010's average extent on this date,
- Extent is 290 k (6.1 %) below 2017 on this date.
- freezing to date from minimum is 313k (53.5%) less than the 10 year average
- on average 5.9% of the increase in extent done.

The table of differences in extent also shows how much 2007 and 2012 remain outliers in the record, while the first table of outcomes shows that in those years extent increase in the following freezing season was far above average. Hence an extra line in the table based on average extent increase in the last 5 years has been added.

On average , extent at 29th September is 305k ABOVE extent on August 31. In contrast, extent on 28 September 2018 is 12k BELOW extent on Aug 31 2018.

GFS says the Arctic temperature anomaly will be around +3 degrees celsius for at least the next 5 days (this I believe), and then increasing to well over 4 degrees by day 10. This is a pattern with GFS - like the Farmers' Almanac, just once in a while such predictions come true, but many times not. However, a generally slow freezing season looks on the cards at least for the next few days though perhaps not for the CAA, the eastern end of the Beaufort, and maybe the Hudson and Baffin (very cold North Central Canada), and also the Greenland Sea.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1777 on: September 30, 2018, 02:38:13 PM »
NSIDC Total Area as at 29 September (5 day trailing average) =  3,437,807 km2

Slow area gain continues, so area now 231k less than 2017 on this day.

Total Area gain           9 k ,

Central Seas LOSS      8 k,                                 
Peripheral Seas gain   17 k, just about all in the Greenland Sea
Other Seas loss           0 k, all seas <5% of max.

Greenland Sea              gain     16k (62k in five days)
Canadian Archipelago    gain    14 k
East Siberian Sea (ESS) gain 10 k ,
Central Arctic Sea          loss  31 k, - 33k, 25 k, 14 k the days before. warmth / weather pushing polewards in the Atlantic front.

Freezing looks like it has taken hold. Attention switches to the pace of that freezing and where it is happening.

Note:-  Daily Extent went down by 21k on this day.
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kassy

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Re: 2018 sea ice area and extent data
« Reply #1778 on: September 30, 2018, 10:02:58 PM »
Ger:
GFS says the Arctic temperature anomaly will be around +3 degrees celsius for at least the next 5 days (this I believe), and then increasing to well over 4 degrees by day 10. This is a pattern with GFS - like the Farmers' Almanac, just once in a while such predictions come true, but many times not.

Since it is about anomalies is this increase to 4 not the weather staying the same with the ice staying about the same so lagging wrt the historical baseline which usually had more ice so it hovers closer to 0?

If so the forecast is not that crazy because with the historically faster refreeze temps the region would be cooler then it is now.

Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1779 on: September 30, 2018, 10:57:03 PM »
Ger:
GFS says the Arctic temperature anomaly will be around +3 degrees celsius for at least the next 5 days (this I believe), and then increasing to well over 4 degrees by day 10. This is a pattern with GFS - like the Farmers' Almanac, just once in a while such predictions come true, but many times not.

Since it is about anomalies is this increase to 4 not the weather staying the same with the ice staying about the same so lagging wrt the historical baseline which usually had more ice so it hovers closer to 0?

If so the forecast is not that crazy because with the historically faster refreeze temps the region would be cooler then it is now.
Kassy, as the cops say "GFS has form". It (in my recollection) is often OK for the first 5 days outlook, but after that predicts large and larger deviations from the average. So while I rely on the first 5 days outlook I take the next 5 days with a bucketful of salt. Mind you, it would be no surprise if the Arctic temp anomaly stays up at around +3 celsius while much of Canada stays cold for a good many days. And thus no surprise if Arctic sea ice extent continues to increase a good bit slower than average until....?
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Re: 2018 sea ice area and extent data
« Reply #1780 on: October 01, 2018, 05:39:55 AM »
[ADS-NIPR-JAXA] ASI Extent.

September 30th, 2018: 4,739,473 km2, an increase of 9,858 km2.
2018 is the 3rd 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.

Neven

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Re: 2018 sea ice area and extent data
« Reply #1781 on: October 01, 2018, 05:41:37 AM »
With September now behind us, maybe one interesting JAXA tidbit: the daily average for September was -87. That's the only time this has happened in the 2005-2018 period, meaning it's the only time  the last day of September was lower than the last day of August.
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Re: 2018 sea ice area and extent data
« Reply #1782 on: October 01, 2018, 09:08:27 AM »
JAXA ARCTIC EXTENT 4,739,473 km2(September 30, 2018)

Just to add to Juan's post  -

- Weak extent increase 10k,
- Extent is 261 k  (5.5 %) below the 2010's average extent on this date,
- Extent is 309 k (6.5 %) below 2017 on this date.
- freezing to date from minimum is 368k (56.6%) less than the 10 year average
- on average 6.5% of the increase in extent done.

The table of differences in extent also shows how much 2007 and 2012 remain outliers in the record, while the first table of outcomes shows that in those years extent increase in the following freezing season was far above average. Hence an extra line in the table based on average extent increase in the last 5 years has been added.

On average , extent at 30th September is 371k ABOVE extent on August 31. In contrast, extent on 30 September 2018 is 2.6k BELOW extent on Aug 31 2018.

GFS says the Arctic temperature anomaly will be around +3 degrees celsius for at least the next 5 days apart from Canada and the CAA which will continue to have well below average temperatures. i.e. outlook is for slow extent increase.

ps: The opposite is happening in the Antarctic - melting has not started at all.
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Re: 2018 sea ice area and extent data
« Reply #1783 on: October 01, 2018, 01:26:20 PM »
Looked for an extent-vs-time graph where the extent is the average over the preceding year and found it here (nice site!): https://sites.google.com/site/marclimategraphs/_/rsrc/1536226652563/collection/G12.jpg

Interesting & looks reasonably linear.

Just eye-balling, I don't see a lot of year-to-year auto-correlation so perhaps there is just the long term trend and the ice extent does, to a good approximation, forget what happened last year.
« Last Edit: October 01, 2018, 01:35:23 PM by slow wing »

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Re: 2018 sea ice area and extent data
« Reply #1784 on: October 01, 2018, 01:38:26 PM »
Another version of Slow wing's graph, with volume for context: 






Credit to Ned W on this thread:
https://forum.arctic-sea-ice.net/index.php/topic,2342.0.html

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Re: 2018 sea ice area and extent data
« Reply #1785 on: October 01, 2018, 05:25:25 PM »
The decline in volume and extent minimums does appear to have stalled over the past 7 to 10 years. Not so the maximums which continue to decline year over year.

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Re: 2018 sea ice area and extent data
« Reply #1786 on: October 01, 2018, 06:26:10 PM »
NSIDC Total Area as at 30 September (5 day trailing average) =  3,470,912 km2

Total Area gain 33 k. Below average area gain continues, so area now 257k less than 2017.

Central Seas     gain       15 k,                                 
Peripheral Seas gain       17 k, just about all in the Greenland Sea
Other Seas       gain         0 k,

Individual Seas
Greenland Sea              gain     14k (76k in six days)
Canadian Archipelago    gain     14 k
East Siberian Sea (ESS) gain      7 k ,
Central Arctic Sea          loss      2 k -31k, -33k, -25k, -14k the days before. Losses at an end?

Freezing has taken hold but may very well continue to be slow. Attention switches to the pace of that freezing and where it is happening.

It has been very cold, is very cold, and will continue to be very cold in the Canadian Archipelago. A super graph for the Denier Rearguard attached.
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Re: 2018 sea ice area and extent data
« Reply #1787 on: October 01, 2018, 06:41:42 PM »
The decline in volume and extent minimums does appear to have stalled over the past 7 to 10 years. Not so the maximums which continue to decline year over year.

Well, people keep saying that, but Tamino's blog seems to come to another conclusion.

Here's his take on decline in yearly average extent 1979-2017.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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Re: 2018 sea ice area and extent data
« Reply #1788 on: October 01, 2018, 06:43:32 PM »
Why do you think it has stalled over the last years ? Could it be related with that extra snow and meltwater early in the meltseason? Last year there was above average snow in Canada . And it was a slow start of the meltseason in several places .How were the years before that, was the snowfall normal or above average in Canada.

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Re: 2018 sea ice area and extent data
« Reply #1789 on: October 01, 2018, 08:16:00 PM »
The decline in volume and extent minimums does appear to have stalled over the past 7 to 10 years. Not so the maximums which continue to decline year over year.

In extent, we could talk that it stall for 6 years on summer, because the outlier will be 2012, the seventh year. But in volume, I think that it has not stall. The difference seems to me that is not that high.

Let's wait for PIOMAS September data, to analyze this subject.
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 #1790 on: October 01, 2018, 08:28:02 PM »
Looked for an extent-vs-time graph where the extent is the average over the preceding year and found it here (nice site!): https://sites.google.com/site/marclimategraphs/_/rsrc/1536226652563/collection/G12.jpg

Interesting & looks reasonably linear.

Just eye-balling, I don't see a lot of year-to-year auto-correlation so perhaps there is just the long term trend and the ice extent does, to a good approximation, forget what happened last year.
Here is something on similar lines using NSIDC Daily Extent previous 365 days average. Going down.
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Re: 2018 sea ice area and extent data
« Reply #1791 on: October 01, 2018, 09:19:20 PM »
The decline in volume and extent minimums does appear to have stalled over the past 7 to 10 years. Not so the maximums which continue to decline year over year.

Well, people keep saying that, but Tamino's blog seems to come to another conclusion.

Here's his take on decline in yearly average extent 1979-2017.

And this chart, while interesting, in no way refutes the observation that the decline in minimum extent seems to have stalled while the decline in maximum extent continues.

Shared Humanity

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Re: 2018 sea ice area and extent data
« Reply #1792 on: October 01, 2018, 09:22:41 PM »
Why do you think it has stalled over the last years ? Could it be related with that extra snow and meltwater early in the meltseason? Last year there was above average snow in Canada . And it was a slow start of the meltseason in several places .How were the years before that, was the snowfall normal or above average in Canada.

I am of the opinion that both the continued decline in maximum extent and stall in the decline of minimum extent are both related to the transition of the Arctic from a dry desert environment to a more humid cloudy environment. Clouds in the winter inhibit the freeze by preventing heat from escaping into space while clouds in the summer inhibit melt due to reduced insolation.

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Re: 2018 sea ice area and extent data
« Reply #1793 on: October 01, 2018, 10:08:31 PM »
In my opinion the "Atlantification" of Barents, Kara and neighbouring seas has already taken over. Combined with some extra warm and moist air from the Atlantic (and, in parts, also on the Pacific side) the re-freezing is delayed for days or even weeks compared to earlier decades. 2016 is the best example for this behaviour. And in that sense, 2016 will not be an outlier but become more and more the standard situation in future years. This is a real change in the trend, and it may not be directly visible in fast reducing Septembar minima, the "poster child" so to say. But it has, of course, an impact on lower extent and area numbers in fall and early winter and is therefore one brick in the wall of more and more diminishing sea ice maxima in early spring.
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Re: 2018 sea ice area and extent data
« Reply #1794 on: October 01, 2018, 10:33:17 PM »
the thing with the minimum kind of stalling (if that is so) has mostly to do with the fact that where the remaining ice is, in the CAB and the CAA, it's most difficult to melt because the season for serious melt in the CAB is very short and if the weather does not exactly hit bulls eye with it's timing the declining sun-angle etc. makes it almost impossible for that ice to melt significantly, except perhaps should there be a specific wind and current pattern that favours export on a large scale.

nevertheless the term "stall" i'd only support when accompanied by the term "kind off" as many have done.

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Re: 2018 sea ice area and extent data
« Reply #1795 on: October 02, 2018, 04:47:28 AM »
With September now behind us, maybe one interesting JAXA tidbit: the daily average for September was -87. That's the only time this has happened in the 2005-2018 period, meaning it's the only time  the last day of September was lower than the last day of August.

Indeed, it has been an unprecedented September. Winter just does not want to kick in over the Arctic Ocean.

Another indication of this is the sea ice extent graph from Wipneus over the CAB.
The line just goes in the opposite direction from prior years.
Amazing.

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Re: 2018 sea ice area and extent data
« Reply #1796 on: October 02, 2018, 05:42:22 AM »
Large region of ice winking out in the ESS, balanced by continued growth in the Beaufort and Greenland Sea.
I wouldn't be surprised if today's JAXA extent change comes in slightly negative.

Slightly positive still, 10K, but maybe tomorrow.

[ADS-NIPR-JAXA] ASI Extent.

October 1st, 2018:  4,734,314 km2, a drop  :o of -5,159 km2
(forecasted on this Forum by Neven, Oren and others  ;) ).
2018 is the 3rd lowest on record.
« Last Edit: October 02, 2018, 05:49:14 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.

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #1797 on: October 02, 2018, 06:58:33 AM »
JAXA ARCTIC EXTENT 4,734,314 km2(October 1, 2018)

Just to add to Juan's post  -

- Extent decrease 5k,
- Extent is 317 k  (6.7 %) below the 2010's average extent on this date,
- Extent is 358 k (7.6 %) below 2017 on this date.
- freezing to date from minimum is 434k (61%) less than the 10 year average
- on average 7.1% of the increase in extent done.

A daily extent decrease in October is rare but not unprecedented, having occurred 9 times since 2002.

An extra line in the table based on average extent increase in the last 5 years has been added. This is because extent gain in 2012-13 was so large (rebound from record low minimum) that it distorts the average.

GFS says the Arctic temperature anomaly will be around +4 degrees celsius by Saturday (and beyond) apart from Canada and the CAA which will continue to have well below average temperatures. i.e. outlook is for slow extent increase for the next 5 days and perhaps for the next 10 days. We may be observing something of an event unfolding

ps: The opposite is happening in the Antarctic - melting has not started at all.
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Re: 2018 sea ice area and extent data
« Reply #1798 on: October 02, 2018, 07:40:04 AM »
The decline in volume and extent minimums does appear to have stalled over the past 7 to 10 years. Not so the maximums which continue to decline year over year.

Well, people keep saying that, but Tamino's blog seems to come to another conclusion.

Here's his take on decline in yearly average extent 1979-2017.

And this chart, while interesting, in no way refutes the observation that the decline in minimum extent seems to have stalled while the decline in maximum extent continues.
True that.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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Re: 2018 sea ice area and extent data
« Reply #1799 on: October 02, 2018, 11:23:24 AM »
Atlantification and Pacification

The Atlantic front is pushing the open ocean towards 85 degrees north.
On the Pacific side the open ocean is pushing towards 80 degrees north.

That's about 350 miles, 550 kilometres, difference. Just thought I would post it to show that difference.
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