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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #2050 on: January 01, 2021, 01:49:27 PM »
JAXA Data - a bit more

Despite the extreme sea ice extent recovery in late October early November, extent ended the year at 3rd lowest in the 42 year satellite record.

The December monthly average, at 11.24 million km2, is 2nd lowest in the satellite record, almost exactly at the trend value. This is 0.24 million km2 more than the record low of Dec 2016 and 0.18 million km2 less than Dec 2019.
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NevB

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Re: 2020 Sea ice area and extent data
« Reply #2051 on: January 01, 2021, 03:13:30 PM »
Just a quick note, to deeply thank Juan and Gerontocrat for your daily updates.
I'm sure there is a lot of us coming here every day to check. Truly thanks.

A serene and healthy New Year to everybody!

+1 I also would like to thank you both for putting your time into this.

Pagophilus

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Re: 2020 Sea ice area and extent data
« Reply #2052 on: January 01, 2021, 04:41:56 PM »
Just a quick note, to deeply thank Juan and Gerontocrat for your daily updates.
I'm sure there is a lot of us coming here every day to check. Truly thanks.

A serene and healthy New Year to everybody!

+1 I also would like to thank you both for putting your time into this.
My thanks also.  And a happy and healthy 2021 to you all.
Sic transit glacies mundi

Shared Humanity

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Re: 2020 Sea ice area and extent data
« Reply #2053 on: January 01, 2021, 04:51:18 PM »
We all have certain routines in our lives. One of my morning routines is to visit this Sea Ice Area and Extent Data thread. Thank you for all that you do for this community. May we all have a much better year then the sucky one we just finished.

gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #2054 on: January 01, 2021, 04:55:28 PM »
NSIDC Total AREA as at 31-Dec-2020 (5 day trailing average) 11,031,837 KM2         
         
Total Area         
 11,031,837    km2      
-162,333    km2   <   2010's average.
-382,664    km2   <   2019
-580,700    km2   <   2000's average.
         
Total Change    18    k   gain
Peripheral Seas    3    k   gain
Central Seas___    15    k   gain
         
Peripheral Seas         
Okhotsk______    9    k   gain
Bering _______   -4    k   loss
Hudson Bay___   -3    k   loss
Baffin  Bay____   -6    k   loss
St Lawrence___   -2    k   loss
Greenland____    9    k   gain
Barents ______   -0    k   loss
         
Central Arctic  Ocean Seas         
Chukchi______   -2    k   loss
Beaufort_____    1    k   gain
CAA_________   -0    k   loss
East Siberian__    2    k   gain
Central Arctic_    6    k   gain
Laptev_______   -1    k   loss
Kara_________    8    k   gain
         
Sea ice area gain on this day 18 k, 38 k less than the 2010's average gain of 56 k         
         
- 2020 area is at position #3 in the satellite record.         
- 2020 Area is 162 k less than the 2010's average         
- 2020 Area is 581 k less than the 2000's average         
- 2020 Area is 444 k more than 2016         
- 2020 Area is 383 k less than 2019          
- 2020 Area is 138 k less than 2012         
___________________________________________         
NSIDC Total EXTENT as at 31-Dec-2020 (5 day trailing average) 12,522,694 KM2         
         
NSIDC Sea ice EXTENT gain on this day 28 k, 27 k less than the 2010's average gain of 55k         
         
- 2020 EXTENT is at position #5 in the satellite record.         
- 2020 EXTENT is 88 k less than the 2010's average         
- 2020 EXTENT is 538 k less than the 2000's average         
- 2020 EXTENT is 109 k more than 2016         
- 2020 EXTENT is 194 k less than 2019          
- 2020 EXTENT is 218 k less than 2012         
___________________________________________         
Note: Click an image for full-size         
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #2055 on: January 01, 2021, 06:23:03 PM »
NSIDC EXTENT Data - some more

The December monthly average at 11.49 million km2 is 2nd lowest in the satellite record, and just 55k below the trend value for Dec 20.

The 365 Day Trailing Average could be at a record low by Spring '21.
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #2056 on: January 01, 2021, 06:28:22 PM »
NSIDC AREA Data - some more

The December monthly average at 9.97 million km2 is 2nd lowest in the satellite record, and at 187k below the trend value for Dec 20 is 4 years ahead of trend.

The 365 Day Trailing Average AREA could be at a record low by late '21. This is later than for EXTENT due to the spectacularly low area values throughout 2016 and into early 2017.
"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)

charles_oil

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Re: 2020 Sea ice area and extent data
« Reply #2057 on: January 01, 2021, 06:50:35 PM »
Plus another one +1 - a regular read for the updates - thanks for all you do. 


Happy New Year too.

Juan C. García

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Re: 2020 Sea ice area and extent data
« Reply #2058 on: January 02, 2021, 05:29:22 AM »
Hi!

We will continue in this new thread:

2021 Sea ice area and extent data
https://forum.arctic-sea-ice.net/index.php/topic,3370.0.html#new
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: 2020 Sea ice area and extent data
« Reply #2059 on: January 02, 2021, 09:17:10 AM »
Yeah, a big thx from me too, it's one of my favorite forum topics on the internet because of the great daily updates :)

oren

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Re: 2020 Sea ice area and extent data
« Reply #2060 on: January 02, 2021, 11:14:50 AM »
Big thanks to Juan and Gero for their important daily contributions. 2020 is finally over...

gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #2061 on: January 03, 2021, 12:29:43 PM »
JAXA Data - a bit more on 2020

2020 had the lowest average daily sesa ice extent in the satellite record.

The simple daily average daily sea ice extent for the year was 9.674 million km2.
This was 42k less than in 2016, and 285k less than in 2012.

Put in another way, in 2020 there was on average 42k less ice and 42 k more open water for every day of the year than in any other year.
"Para a Causa do Povo a Luta Continua!"
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kassy

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Re: 2020 Sea ice area and extent data
« Reply #2062 on: January 03, 2021, 04:36:04 PM »
Interesting data.

I take it that the three years cited above are the top 3. Could you add a table (or graph) of the other years?
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: 2020 Sea ice area and extent data
« Reply #2063 on: January 03, 2021, 07:16:01 PM »
Interesting data.

I take it that the three years cited above are the top 3. Could you add a table (or graph) of the other years?
Is there some confusion here  ?
The graph above is not the 365 day trailing average.
It is the simple average of daily extent for each year.

Perhaps the attached column graph makes it more obvious.
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kassy

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Re: 2020 Sea ice area and extent data
« Reply #2064 on: January 03, 2021, 11:59:05 PM »
No confusion but i called the years the top years because i was thinking about functional albedo loss which is the same as the bottom years for ext over the year so my bad.

Thanks for the graph.
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.

Stephan

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Re: 2020 Sea ice area and extent data
« Reply #2065 on: January 10, 2021, 10:19:42 PM »
I added the monthly extent value for December 2020 into my long-term plot where I calculate the extent anomalies from 1979 up to now.
The average (1979-2020) December extent is now 12.66 M km². December 2020 had an average extent of 11.49 M km², which is 1.17 M km² less than that long-term average.
The rapid freeze-up in November and December reduced the anomaly we saw in October from the long-term linear trend line. The difference of the actual month from that trend line is -0.08 M km² (calculated from the linear trend line this December should have been at 11.57 M km²).
The slope of the long-term linear trend line has not changed since October (-0.0560).

See attached graph. Click to enlarge.
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #2066 on: February 07, 2021, 07:52:11 PM »
FROM NSIDC DATA -Progress of the Arctic Ocean transforming from an icy desert to open water.

What with one thing and another I never got round to posting the updates for these open water graphs for 2020. The gtaphs look at the percentage of open water rather than the amount of ice.

The first graph is for all 14 seas. It shows
- average open water for the year increased from around 40% in 1980 to just over 50% in 2020,
- average open water for the 3 minimum ice months of August to October increased from around 65% in 1980 to just over 80% in 2020,
- average open water for the 3 maximum ice months of February to April increased marginally from around 20% in 1980 to just over 25% in 2020.
AGW has the most impact in summer (hardly a surprise).

The next 2 graphs look at the 7 central seas of the Hgh Arctic and the 7 Peripheral Seas
The High Arctic
- average open water for the year increased from just under 15% in 1980 to just over 25% in 2020,
- average open water for the 3 minimum ice months of August to October increased from around 30% in 1980 to about 65% in 2020,
- average open water for the 3 maximum ice months of February to April did not increase, at under 5% open water for nearly all years.
Winter sea ice area stll looks pretty solid for the High Arctic.

The 7 Peripheral Seas (See note ***)
- average open water for the year increased marginally from just under 70% in 1980 to just over 75% in 2020,
- average open water for the 3 minimum ice months of August to October increased from wobbling around 95% in 1980 to solidly just under 100% in 2020,
- average open water for the 3 maximum ice months of February to April increased marginally from around 40% in 1980 to around 50% in 2020.
So even in winter these peripheral sea in total are verging on becoming more open water than ice.

I have graphs for groups of seas and individual seas that I hope to give an airing as the days go by.

________________________________________________________________
Note *** Apart from the Hudson, the peripheral seas are bounded by open ocean. So what to use as the area? I used the maximum daily sea ice extent in the satellite record.
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #2067 on: February 10, 2021, 06:07:41 PM »
FROM NSIDC DATA -Progress of the Arctic Ocean transforming from an icy desert to open water.


Grouping seas together is never totally satisfactory. But here goes anyway.

Pacific Gateway - Bering & Chukchi.

Summary
- shows sea ice in the 3 months August to October is pretty much history

Bering Sea.
- there is no sea ice in summer, the freeze is tending later .
- winter sea ice is highly variable, and open water is nearly always over 50%. This reflects that sea ice concentration even in winter is very low.

Chukchi
This a very much a poster for progressive sea ice loss and expanding open water..
- average open water for the year increased from around 25% in 1980 to around 35% in 2020,
- average open water for the 3 minimum ice months of August to October increased from around 55% in 1980 to just over 95% in 2020,
- as yet there is no significant effect on open water at around 5% in the 3 maximum ice months of Feb to April. However, one can see that refreeze is happening later and melt earlier as the years go by.
"Para a Causa do Povo a Luta Continua!"
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oren

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Re: 2020 Sea ice area and extent data
« Reply #2068 on: February 10, 2021, 06:38:27 PM »
A chart I prepared for another thread, which I think should be here too. It helps to show how low 2020 was in terms of JAXA extent.
The chart counts the total number of daily record lows held by each year - from lowest on record for the day, to 4th lowest.
2020 spent more than half the year in 1st or 2nd lowest. 2016 also stands out. On the other hand 2012 really seems like a late summer fluke from this viewpoint, although of course a lot of the damage that led to the record took place earlier.

« Last Edit: February 10, 2021, 06:43:31 PM by oren »

gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #2069 on: February 12, 2021, 07:59:47 PM »
FROM NSIDC DATA -Progress of the Arctic Ocean transforming from an icy desert to open water.


The Canadian Seas - Hudson Bay, Baffin and St Lawrence -
but not the CAA

These 3 peripheral seas have shown some reluctance to respond to AGW. From 1980 to 2020 average open water for the year has only increases from around 60% to around 65%.
You can also see that melting onset is earlier while refreeze starts later.

Hudson Bay
- average open water for the year increased from around 45% in 1980 to around 50% in 2020,
- average open water for the 3 minimum ice months of August to October at close to 100% barely changed at all,
- average open water for the 3 maximum ice months of February to Aprilat 5% to 10% barely changed at all.

Baffin Bay
- average open water for the year increased from around 40% in 1980 to just over 50% in 2020,
- average open water for the 3 minimum ice months of August to October increased from around 95% in 1980 to nearly 100% in 2020,
- extremely variable average open water for the 3 maximum ice months of February to April increased from a range of 20 to 45% in the 1980's to 40 to 50% in the last 10 years.

St Lawrence
- This very small sea is basically ice-free except in winter when annual variation is extremely extreme.
- This most noteworthy characteristic of this sea, that does not show on this graph, is the very low concentration, with extent up to 3 times as high as area even in February.

Click to enlarge images

"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #2070 on: February 18, 2021, 06:24:38 PM »
FROM NSIDC DATA -Progress of the Arctic Ocean transforming from an icy desert to open water.

Grouping togther seas is never totally satisfactory. This group has the Barents+Kara+Laptev+East Siberian(ESS) seas . Included is the ESS even though the far Eastern end is influenced very much by the Bering and Chukchi seas of the Pacific Gateway. But the group includes all seas bordering the Russian and European northern coast.

The first graph is for all 4 seas. It shows a classic increase in open water over time.
- average open water for the year increased from around 30% in 1980 to just over 50% in 2020,
- average open water for the 3 minimum ice months of August to October increased from around 65% in 1980 to around 95% in 2020,
- average open water for the 3 maximum ice months of February to April increased from around 15% in 1980 to around 25% in 2020.
AGW has the most impact in summer (hardly a surprise).
In 2020, average open water for the year was over 50%. This makes this group more of an open water than an icy desert region.

The next graphs look at the individual seas

Barents sea Annual variations in this sea are very high - perhaps as is bordered by the Atlantic Ocean across a wide front.
- average open water for the year increased fromaround 60% in 1980 to circa 85% in 2020,
- average open water for the 3 minimum ice months of August to October increased from wobbling around 95% in 1980 to solidly 100% in 2020,
- average open water for the 3 maximum ice months of February to April increased marginally from around 30% in 1980 to around 60% in 2020.
So even in winter this sea is now more open water than ice.

The Kara
- average open water for the year increased from just over 20% in 1980 to just over 50% in 2020,
- average open water for the 3 minimum ice months of August to October increased from wobbling around 90 to 100% in 1980 to 1990 to over 95% in the recent years to 2020. It is not 100% because of a mask used by NSIDC
- average open water for the 3 maximum ice months of February to April  increased from around 5% in 1980 to around 10% in 2020,
Winter sea ice area stll looks pretty solid .
In 2020, average open water for the year was over 50%. This makes this group more of an open water than an icy desert region.


The Laptev
- average open water for the year increased from just under 20% from 1980 to 1990, to just over 40% in 2020,
- average open water for the 3 minimum ice months of August to October increased from wobbling around 40 to 50% in 1980 to 1990 to over 95% in2020. Annual variation is extreme
- average open water for the 3 maximum ice months of February to April  stayed at around 5% in 1980 to 2020,
Winter sea ice area stll looks very solid .

________________________________________________________________
Note - see next post for the ESS
« Last Edit: February 18, 2021, 07:29:54 PM by gerontocrat »
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #2071 on: February 18, 2021, 06:32:20 PM »
FROM NSIDC DATA -Progress of the Arctic Ocean transforming from an icy desert to open water.
(continued)

The ESS
- average open water for the year increased from 10% in 1980 to just over 30% in 2020,
- average open water for the 3 minimum ice months of August to October increased from wobbling around 25 to 35% in 1980 to 1990 to over 90% in 2020.
- average open water for the 3 maximum ice months of February to April  stayed at around 5% in 1980 to 2020,
Winter sea ice area stll looks pretty solid .

The use of the seas from Europe to the Bering Strait as a major commerical waterway is bound to increase.
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #2072 on: February 18, 2021, 07:28:34 PM »
FROM NSIDC DATA -Progress of the Arctic Ocean transforming from an icy desert to open water. (continued)

This group has the Canadian Archipelago, thye Beuafort and the Central Arctic region.  It is regarded very much as the last bastion - The Forlorn Hope - of Arctic Sea ice.

The first graph is for all 3 seas.
- average open water for the year increased from around 10% in 1980 to around 15% in 2020,
- average open water for the 3 minimum ice months of August to October increased from around 20 to 30% in 1980 to 1990 to around 40% in 2020,
- average open water for the 3 maximum ice months of February to April was less than 5% for nearly every year.
AGW has the most impact in summer (hardly a surprise).

The next graphs look at the individual seas


Beaufort Annual variations in this sea are very high - especially during the minimum sea ice months
- average open water for the year increased from around 10-20% in 1980 to 1990 to 20-30% in the decade 2011 to 2020,
- average open water for the 3 minimum ice months of August to October from around 20 to 50% in 1980 to 1990 to 70-80% in the recent years to 2020,
- average open water for the 3 maximum ice months of February to April  stayed at below 5% from 1980 to 2020,

The Canadian Archipelago Area -CAA
- average open water for the year increased fromaround 20% in 1980 to around 25% in 2020,
- average open water for the 3 minimum ice months of August to October increased from wobbling around 50% in 1980 to 1990 to around 60% in the recent years to 2020.
- average open water for the 3 maximum ice months of February to April  if anything declined from just over 5%  in 1980 to just under 5% in 2020,
Winter sea ice area looks very solid .
This sea shows a minimal impact of AGW on sea ice area


The Central Arctic - the big one at 3.224 million KM2
- average open water for the year increased from around 5% in 1980 to around 10% in 2020,
- average open water for the 3 minimum ice months of August to October increased from 10% in 1980 to 1990 to 30% in 2020.
- average open water for the 3 maximum ice months of February to April  stayed at close to zero for nearly all years
Winter sea ice area stll looks very solid .
________________________________________________________________
See next post for the remaining seas.
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: 2020 Sea ice area and extent data
« Reply #2073 on: February 18, 2021, 07:54:26 PM »
FROM NSIDC DATA -Progress of the Arctic Ocean transforming from an icy desert to open water. (continued)

These last two seas did not fit conveniently into any groups


The Greenland Sea
This sea is a bit special. If not for ice exported down the Fram Strait from the Central Arctic, there would not be a lot of ice in this sea, being more in the North Atlantic than the Arctic Ocean.

Thus how much ice in that sea ia as much due to ice imported from the Arctic as to local weather conditions, which contributes to high annual variability in ice cover.

- average open water for the year increased from around 60% in 1980 to around 70% in 2020,
- average open water for the 3 minimum ice months of August to October increased from around 75% in 1980 to 1990 to around 80% in the recent years to 2020.
- average open water for the 3 maximum ice months of February to April increased from around 45% in 1980 to 1990 to around 55% in the recent years to 2020.


The Okhotsk.
The NSIDC border even includes part of the Japan Sea, Physically separate from the Arctic Ocean and even the Bering Sea, this is an oddity but is not small - 1.62 million Km2

- average open water for the year has stayed between 80 and 90% for nearly all years since 1980,
- average open water for the 3 minimum ice months of August to October is 100% for all years.
- average open water for the 3 maximum ice months of February to April increased from under 30% in 1980 to over 50% in the recent years to 2020.
______________________________________________________
That's the lot, chapesses and chaps - small updates in early April and early May

"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)