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Rich

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Re: 2019 sea ice area and extent data
« Reply #1500 on: July 07, 2019, 03:44:10 PM »
3.0M km2 area decline in 26 days. Nearly a month @115k average.

Losses in the last couple of days in the CAB picking up. If the 5 day average has popped to 33.5k, we probably lost close to 100k in the last 2 days.
« Last Edit: July 08, 2019, 06:11:25 AM by Rich »

Killian

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Re: 2019 sea ice area and extent data
« Reply #1501 on: July 07, 2019, 04:35:36 PM »
JAXA extent changes needed as daily average to get into record territory.
(The 5th, 6th and 7th are vs. '16 while the 8th and 9th are vs. '12.)

7/5:   -115k
7/6:   -105k avg
7/7:   - 85k avg
7/8:   - 87k avg ('12)
7/9:   -100k avg

With the losses of the last two days, we need > 60k loss to be in record territory for the 7th, which seems very likely to happen, and just >75k average for the two days to be in record territory for the eigth, which also seems very likely. However...

2012 had a huge 150k loss the next day, so record territory for the 9th will require an avg. of > 100k over the next three days.

Cheers

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #1502 on: July 08, 2019, 05:47:06 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

July 7th, 2019:
     8,285,374 km2, a century drop of -125,250 km2.
     2019 is now the 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.

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Re: 2019 sea ice area and extent data
« Reply #1503 on: July 08, 2019, 06:02:01 AM »
Told ya all.



Never underestimate or ignore surface temperatures.

They are the end all be all. 

2019 might not finish the lowest but it will be close. 
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1504 on: July 08, 2019, 06:55:07 AM »
JAXA ARCTIC EXTENT :-  8,285,374 km2(July 7, 2019)

- Extent is lowest in the satellite record.
- Extent loss on this day 125 k, 36 k more than the average loss on this day of 89 k.
- Extent loss from maximum 5,986 k, 309 k (5.5%) greater than the average of 5,676 k loss from maximum by this day,
- On average 57.4% of the melting season done, with 68 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 4.08 million km2, 4th lowest in the satellite record, and 0.90 million km2 above the 2012 low of 3.18 million km2.
Looking at the last 5 years average remaining melt gives a result of 4.09 million km2, also 4th lowest, and 0.91 million km2 above 2012.

The first 7 days in July have a mixed picture, certainly more above than below average area loss.

Other Stuff
Weather
GFS over the next 7 days showing temperature anomalies in a  temperature anomaly range of +0.5 to +1.5 degrees celsius.
- over the Arctic Ocean itself temperatures a bit above average,
- the CAA, Baffin Bay and Hudson Bay are mostly warm,
- Western Canada stays mostly cool.
- Alaska and Eastern Siberian  really warm,
- Central Siberia and Western Siberia mostly cool.

The winds described in previous posts seem to have mostly faded away, apart from strongish winds along the Russia shore from the Laptev to the Kara. The Arctic Ocean also looking very dry.

Area Loss Outlook
We are now in the period of maximum daily extent loss that lasts until mid or late July and then very gradually declines. Extent loss this month well above average. Future extent losses will be ? ?
_____________________________________________________________________
Future extent loss?
On every measure (JAXA extent, NSIDC daily and 5 day area and extent, and volume), 2019 is now lowest in the satellite record. Hold the front page!

To end the season on a record low, remaining extent loss must be more than 21 % above the previous 10 years' average.
For a BOE,  remaining extent loss must be more than 70 % above the previous 10 years' average.

The June volume data persuaded me to drop my minimum guesstimate to below 4 million km2 from at exactly 4 million km2. This assumes remaining extent loss will continue at around 5% more than average.
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1505 on: July 08, 2019, 07:21:51 AM »
OK, so JAXA daily extent and the other metrics have July 7 as the lowest in the satellite record.

But this does not make the 365 day average the lowest in the satellite record. That still belongs to around March 2017, after the continuously low extent in 2016. If 2019 continues on its current path, the 365 day average could move into record low territory in December of this year or early in 2020.

Now that will really be a record for the record books.
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Re: 2019 sea ice area and extent data
« Reply #1506 on: July 08, 2019, 08:51:54 AM »
But this does not make the 365 day average the lowest in the satellite record. That still belongs to around March 2017, after the continuously low extent in 2016. If 2019 continues on its current path, the 365 day average could move into record low territory in December of this year or early in 2020.

Now that will really be a record for the record books.

2016 was marked by four record months, as was 2012.

https://twitter.com/ZLabe/status/1123770505125928961

---------------------
Quote
Record low #Arctic sea ice extent months - @NSIDC data (satellite-era from 1978/1979)
---------------------
2018 : January
2018 : February
2017 : March
2019 : April
2016 : May
2016 : June
2012 : July
2012 : August
2012 : September
2012 : October
2016 : November
2016 : December


Records of 2012 are the oldest among any months, so their fall is obvious.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1507 on: July 08, 2019, 02:24:28 PM »
NSIDC Total Area as at 7 July 2019 (5 day trailing average) 6,101,223 km2
                        
Total Area         
 6,101,223    km2      
-496,520    km2   <   2010's average.
-404,540    k   <   2018
-1,158,819    k   <   2000's average.
         
Total Area Change   -113    k   loss
Peripheral Seas   -15    k   loss
Central Seas__   -84    k   loss
Other Seas___   -14    k   loss
         
Peripheral Seas         
Bering _______   -1    k   loss
Baffin  Bay____   -6    k   loss
Greenland____   -7    k   loss
Barents ______   -1    k   loss
         
CAB Seas         
Beaufort_____   -5    k   loss
CAA_________   -2    k   loss
East Siberian__   -17    k   loss
Central Arctic_   -31    k   loss
         
Kara_________   -12    k   loss
Laptev_______   -12    k   loss
Chukchi______   -6    k   loss
         
Other Seas         
Okhotsk______   -0    k   loss
St Lawrence___    0    k   gain
Hudson Bay___   -14    k   loss

Area loss 113 k, 9 k more than the 2010's average loss of 104 k on this day.

Total area Lowest, 257 k LESS than 2016, and 95 k less than 2012

2019 is the front runner as regards area again, but for how long?

Other Stuff
Weather
GFS over the next 7 days showing temperature anomalies in a  temperature anomaly range of +0.5 to +1.5 degrees celsius.
- over the Arctic Ocean itself temperatures a bit above average,
- the CAA, Baffin Bay and Hudson Bay are mostly warm,
- Western Canada stays mostly cool.
- Alaska and Eastern Siberian  really warm,
- Central Siberia and Western Siberia mostly cool.

The winds described in previous posts seem to have mostly faded away, apart from strongish winds along the Russia shore from the Laptev to the Kara. The Arctic Ocean also looking very dry.

A cliff or not a cliff
We are in the period of maximum daily area loss that lasts until late July.
Area losses have ticked up a lot in the last 10 days, but moderating.
Being a five day trailing average, above average area losses should continue for 2 or 3 days at minimum.
A steep downward slope, separating 2019 from 2016 and now from 2012.

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).
________________________________________________________________________
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1508 on: July 08, 2019, 02:30:18 PM »
The attached graphs give one more confidence in above average longer-term remaining melt this season leading to a low minimum. They are all about the High Arctic (7 central seas).
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Killian

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Re: 2019 sea ice area and extent data
« Reply #1509 on: July 08, 2019, 02:33:54 PM »
vs. '16 while the 8th and 9th...

Turns out I was sleeping on 2011, which is the low starting the 8th until the 25th of July, and is 30k lower on the 8th and 20k lower on the 9th.

Quote
and just >75k average for the two days to be in record territory for the eigth... 2012 had a huge 150k loss the next day, so record territory for the 9th will require an avg. of > 100k over the next three days.

With the drop of @ 120k on the 7th, and accounting for 2011, a fall of > 60k will put the ice at record low extent on the 8th. 2011 had a large drop of 140k to end at 8.09 M sq km on the 9th. 2019 will need to drop > 200k, 100k avg/day, to be lowest on that date.

2011 drops 140k on each of the next two days (with a -170k day ahead!) for a large 240k total. It will only be due to being 80k lower on the 7th that 2011 is lowest on the 9th.

I'm pretty sure '19 will be lower for the 8th as conditions haven't shifted much, but not as confident for the 9th as before, but even more so with an unanticipated 20k more needed. Still, conditions still favor reduced extent, just not as strongly as during the past week or so.

Call it low on the 8th, 2nd on the 9th. Maybe. :-)

Looking further out, it will be tough for 2019 to remain at record lows as 2011 just kept dropping, and after a massive 170k drop in the 12th, chances are 2011 will be low until the 25th when 2012 makes a massive drop to take over the low spot.

Cheers

(If these posts are irritating anyone, let me know. The short-term predictions are kinda fun, but not necessary. As they draw on all the commentary and the same imagery you all see, I don't go into conditions much, which may not please some here...

Let me know.)

Killian

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Re: 2019 sea ice area and extent data
« Reply #1510 on: July 08, 2019, 02:38:13 PM »
The attached graphs give one more confidence in above average longer-term remaining melt this season leading to a low minimum. They are all about the High Arctic (7 central seas).

Are you going to add 2011 for the 8th through the 24th given it holds the record lows for that time period?

Rich

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Re: 2019 sea ice area and extent data
« Reply #1511 on: July 08, 2019, 03:22:25 PM »
Is there any way to find out where the CAB losses are coming from?

At 2.8M km2, that bucket is ~ 1/2 of all that remains and we've lost almost 0.3M km2 in the last 2 weeks from the CAB.

Anyone with NSIDC connections?

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1512 on: July 08, 2019, 03:47:42 PM »
The attached graphs give one more confidence in above average longer-term remaining melt this season leading to a low minimum. They are all about the High Arctic (7 central seas).

Are you going to add 2011 for the 8th through the 24th given it holds the record lows for that time period?
On what measure was 2011 at record low during that time?
NSIDC Total Area  5 day / Daily,
NSIDC Total extent 5 day / daily,

I can't find it. But I is tired.

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Re: 2019 sea ice area and extent data
« Reply #1513 on: July 08, 2019, 03:57:22 PM »
Is there any way to find out where the CAB losses are coming from?

The map tells you where.
Just about any open water North of 80 degrees.
At the moment that looks mostly the Barents / CAB boundary.
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Rich

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Re: 2019 sea ice area and extent data
« Reply #1514 on: July 08, 2019, 04:55:24 PM »
Thank you. That's pretty straightforward.

Killian

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Re: 2019 sea ice area and extent data
« Reply #1515 on: July 08, 2019, 07:35:54 PM »
The attached graphs give one more confidence in above average longer-term remaining melt this season leading to a low minimum. They are all about the High Arctic (7 central seas).

Are you going to add 2011 for the 8th through the 24th given it holds the record lows for that time period?
On what measure was 2011 at record low during that time?
NSIDC Total Area  5 day / Daily,
NSIDC Total extent 5 day / daily,

I can't find it. But I is tired.

My bad. You're specifying CAB/High Arctic. I've been looking at JAXA's ASIE.

Nevermind!

Alphabet Hotel

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Re: 2019 sea ice area and extent data
« Reply #1516 on: July 08, 2019, 07:39:39 PM »
NSIDC daily extent

magnamentis

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Re: 2019 sea ice area and extent data
« Reply #1517 on: July 08, 2019, 08:44:48 PM »
Is there any way to find out where the CAB losses are coming from?

At 2.8M km2, that bucket is ~ 1/2 of all that remains and we've lost almost 0.3M km2 in the last 2 weeks from the CAB.

Anyone with NSIDC connections?

- export

- thin and fractured ice melting easier over all

- high temperatures over an extended period of time

- high insolation in general

- not as many freezing days in winter

- generally more mobile ice

- less replenishment from the sibirien side because in part it drifted towards the atlantic side and in
. it's melting now before reaching >80N etc.

independently whether i forgot something or whether it's 100% like that, there are plenty of reasons and finally what some of us expected since years is starting to show. the ever worse state of the ice across the board can't be overpainted with weather events, dispersion and/or compaction. what's not there in sufficient quantity and quality cannot be camouflaged infinitely.

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Re: 2019 sea ice area and extent data
« Reply #1518 on: July 08, 2019, 08:52:01 PM »
Guess what is a bit confusing is all these many weeks, Climate reanalizer has had 80N be slightly shaded pink, yet DMI shows it right on the line.  Still just a hair above most years it seems.
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magnamentis

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Re: 2019 sea ice area and extent data
« Reply #1519 on: July 08, 2019, 08:57:49 PM »
Guess what is a bit confusing is all these many weeks, Climate reanalizer has had 80N be slightly shaded pink, yet DMI shows it right on the line.  Still just a hair above most years it seems.

first of all DMI has always been slightly different, IMO more often off the mark than others but that's not verified by myself thoroughly, it's an subjective impression over the years.

second, there is simply no way that temps will raise much higher than what we have now over ice and that means over large parts of the arctic, especially the CAB.

the differences cause by current conditions will and usually did show from mid August till late November or even later recently.
« Last Edit: July 08, 2019, 09:06:41 PM by magnamentis »

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Re: 2019 sea ice area and extent data
« Reply #1520 on: July 08, 2019, 09:01:10 PM »
When we see DMI 80N lift off that 'latent heat of fusion' dictated line it's time to really worry!!!!
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Re: 2019 sea ice area and extent data
« Reply #1521 on: July 08, 2019, 09:02:18 PM »
Is there any way to find out where the CAB losses are coming from?

At 2.8M km2, that bucket is ~ 1/2 of all that remains and we've lost almost 0.3M km2 in the last 2 weeks from the CAB.

Anyone with NSIDC connections?

NSIDC sea ice concentration images are here:

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

Here's an animation for the past 4 weeks, showing how the ice in the CAB gradually turns from white to blue.  That is mainly due to the spread of melt ponds: NSIDC sea ice area cannot really distinguish melt ponds from open water. 


magnamentis

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Re: 2019 sea ice area and extent data
« Reply #1522 on: July 08, 2019, 09:07:27 PM »
When we see DMI 80N lift off that 'latent heat of fusion' dictated line it's time to really worry!!!!

exactly !

magnamentis

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Re: 2019 sea ice area and extent data
« Reply #1523 on: July 08, 2019, 09:09:07 PM »
That is mainly due to the spread of melt ponds: NSIDC sea ice area cannot really distinguish melt ponds from open water. 

true that of course while that condition/parameter does not change a lot between the years. at least if we consider that he meant this years compared to other years, not sure though.

true either way as a standalone statement.

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Re: 2019 sea ice area and extent data
« Reply #1524 on: July 08, 2019, 09:33:37 PM »
… DMI shows it right on the line.  Still just a hair above most years it seems.

Note the 'average' line is for 1958-2002 when the Arctic was a different beast.  (Don't ask me how it was 'warmer' then.)  Looking through the archive, you'll see recent years have an occasional bump above the above-0ºC green line segment, but averaging between the zero and the green line.  For 2019's trace to be right on the green line is actually rather spectacular!

[Remember, DMI 80N is a North-Pole-centric calculation of temperature and should not be confused with "average" temperature for a territory in the usual sense of the term.]
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Re: 2019 sea ice area and extent data
« Reply #1525 on: July 08, 2019, 10:18:32 PM »
For 2019's trace to be right on the green line is actually rather spectacular!


Yes, exactly.

It's almost always below that green line, and to see it tracking it so closely is a very bad sign.

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Re: 2019 sea ice area and extent data
« Reply #1526 on: July 09, 2019, 05:52:02 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

July 8th, 2019:
     8,135,012 km2, a century drop of -150,362 km2.
     2019 is the 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.

slow wing

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Re: 2019 sea ice area and extent data
« Reply #1527 on: July 09, 2019, 06:26:29 AM »
… DMI shows it right on the line.  Still just a hair above most years it seems.

Note the 'average' line is for 1958-2002 when the Arctic was a different beast.  (Don't ask me how it was 'warmer' then.)  Looking through the archive, you'll see recent years have an occasional bump above the above-0ºC green line segment, but averaging between the zero and the green line.  For 2019's trace to be right on the green line is actually rather spectacular!

[Remember, DMI 80N is a North-Pole-centric calculation of temperature and should not be confused with "average" temperature for a territory in the usual sense of the term.]

That's something I've wondered previously, as well. Why would the North Pole and nearby have been slightly warmer  in those earlier years, when the ice was thicker?

This is just speculation, but it may be that thick ice with few leads better supported melt ponds than today's ice does. Remember, ice ponds also drain away if the ice is porous. So those earlier years may have had a bigger surface fraction as durable melt ponds. These could then heat up in the sun, raising the temperature of the air just above them.

As I say, that's just speculation. It could well be another reason. Does anyone know?

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Re: 2019 sea ice area and extent data
« Reply #1528 on: July 09, 2019, 06:27:24 AM »
JAXA ARCTIC EXTENT :-  8,135,012 km2(July 8, 2019)

3 century breaks in a row starts to count as serious melting.

- Extent is lowest in the satellite record.
- Extent loss on this day 150 k, 52 k more than the average loss on this day of 98 k.
- Extent loss from maximum 6,136 k, 363 k (6.3%) greater than the average of 5,773 k loss from maximum by this day,
- On average 58.4% of the melting season done, with 67 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 4.03 million km2, 3rd lowest in the satellite record, and 0.85 million km2 above the 2012 low of 3.18 million km2.

The first 8 days in July have a mixed picture, now certainly much more above than below average area loss.

Other Stuff
Weather
GFS over the next 7 days showing temperature anomalies in a  temperature anomaly range of +0.5 to +1.7 degrees celsius.
- over the Arctic Ocean itself temperatures a bit above average,
- the CAA, Baffin Bay and Hudson Bay are mostly warm,
- Western Canada stays mostly cool.
- Alaska and Eastern Siberian  really warm,
- Central Siberia and Western Siberia mostly cool.

Area Loss Outlook
We are now in the period of maximum daily extent loss that lasts until mid or late July and then very gradually declines. Extent loss this month well above average. Future extent losses will be ? ?
_____________________________________________________________________
Future extent loss?
On every measure (JAXA extent, NSIDC daily and 5 day area and extent, and volume), 2019 is now lowest in the satellite record.

To end the season on a record low, remaining extent loss must be more than 20 % above the previous 10 years' average.
For a BOE,  remaining extent loss must be more than 70 % above the previous 10 years' average.

The June volume data persuaded me to drop my minimum guesstimate to below 4 million km2 from at exactly 4 million km2. This assumes remaining extent loss will continue at around 2.5% more than average.
______________________________________________________________
Killian has pointed out that 2011 was lowest from 8th to 24th July,, and asked if I would add 2011 to the graphs.
Nope. Too lazy to change the graphs for a flash in the pan.
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1529 on: July 09, 2019, 02:09:35 PM »
NSIDC Total Area as at 8 July 2019 (5 day trailing average) 5,995,583 km2
                        
Total Area         
 5,995,583    km2      
-502,066    km2   <   2010's average.
-401,026    k   <   2018
-1,179,701    k   <   2000's average.
         
Total Area Change   -106    k   loss
Peripheral Seas   -21    k   loss
Central Seas__   -70    k   loss
Other Seas___   -14    k   loss
         
Peripheral Seas         
Bering _______   -1    k   loss
Baffin  Bay____   -9    k   loss
Greenland____   -7    k   loss
Barents ______   -4    k   loss
         
CAB Seas         
Beaufort_____   -3    k   loss
CAA_________   -7    k   loss
East Siberian__   -21    k   loss
Central Arctic_   -11    k   loss
         
Kara_________   -8    k   loss
Laptev_______   -14    k   loss
Chukchi______   -6    k   loss
         
Other Seas         
Okhotsk______   -0    k   loss
St Lawrence___    0    k   gain
Hudson Bay___   -15    k   loss

Area loss 106 k, 3 k less than the 2010's average loss of 109 k on this day.

Total area Lowest, 262 k LESS than 2016, and 134 k less than 2012.

Extent loss (NSIDC and JAXA) playing catchup with area.

Despite area loss back to average, 2019 is strengthening its position as front runner, but for how long?
 
Other Stuff
Weather
GFS over the next 7 days showing temperature anomalies in a  temperature anomaly range of +0.5 to +1.7 degrees celsius.
- over the Arctic Ocean itself temperatures a bit above average,
- the CAA, Baffin Bay and Hudson Bay are mostly warm,
- Western Canada stays mostly cool.
- Alaska and Eastern Siberian  really warm,
- Central Siberia and Western Siberia mostly cool.

The winds described in previous posts seem to have mostly faded away, apart from strongish winds along the Russia shore from the Laptev to the Kara.

A cliff or not a cliff
We are in the period of maximum daily area loss that lasts until late July.
Area losses have ticked up a lot in the last 10 days, but moderating.
Being a five day trailing average, above average area losses should continue for 2 or 3 days at minimum.
A steep downward slope, separating 2019 from 2016 and now from 2012.

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!"
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1530 on: July 09, 2019, 03:19:31 PM »
NSIDC Daily Extent losses very high.
Now lowest in the satellite record.
"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 #1531 on: July 09, 2019, 03:50:27 PM »

The winds described in previous posts seem to have mostly faded away, apart from strongish winds along the Russia shore from the Laptev to the Kara

Being a five day trailing average, above average area losses should continue for 2 or 3 days at minimum.

Excellent observation about the diminishing winds. IMO, a drag on momentum.

I think the string of above average losses was broken yesterday. 106K < 109K ??

kassy

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Re: 2019 sea ice area and extent data
« Reply #1532 on: July 09, 2019, 04:46:03 PM »
… DMI shows it right on the line.  Still just a hair above most years it seems.

Note the 'average' line is for 1958-2002 when the Arctic was a different beast.  (Don't ask me how it was 'warmer' then.)  ...[Remember, DMI 80N is a North-Pole-centric calculation of temperature and should not be confused with "average" temperature for a territory in the usual sense of the term.]

That's something I've wondered previously, as well. Why would the North Pole and nearby have been slightly warmer  in those earlier years, when the ice was thicker?

This is just speculation, but it may be that thick ice with few leads better supported melt ponds than today's ice does. Remember, ice ponds also drain away if the ice is porous. So those earlier years may have had a bigger surface fraction as durable melt ponds. These could then heat up in the sun, raising the temperature of the air just above them.

As I say, that's just speculation. It could well be another reason. Does anyone know?

Could the Arctic becoming cloudier play a role? Probably combined with the meltponds.

We had many years were ´bad summers´ saved the ice.
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.

Alphabet Hotel

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Re: 2019 sea ice area and extent data
« Reply #1533 on: July 09, 2019, 04:48:59 PM »
NSIDC daily extent

b_lumenkraft

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Re: 2019 sea ice area and extent data
« Reply #1534 on: July 09, 2019, 05:07:51 PM »
Poof!

be cause

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Re: 2019 sea ice area and extent data
« Reply #1535 on: July 09, 2019, 06:42:30 PM »
  that was last weeks 2 metre thick ice .. sPoof ice .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

Stephan

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Re: 2019 sea ice area and extent data
« Reply #1536 on: July 09, 2019, 06:55:32 PM »
Analysis of the individual seas' area "relative area wise" from June 22-July 8:
Losses of 53-61%: Hudson, Baffin and Kara (all three of them will probably melt out to > 90%)
Losses of 40-46%: Chukchi and Barents
Losses of 21-28%: Beaufort, ESS, Laptev and Grønland
CAB has lost 10%, CAA has gained 1%.
In summary this is a really significant loss, and different in its persistence and speed from 2018 and 2017 melt seasons.
Seas with almost no ice (if there is any at all) were not analysed.
It is too late just to be concerned about Climate Change

magnamentis

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Re: 2019 sea ice area and extent data
« Reply #1537 on: July 09, 2019, 07:33:43 PM »
  that was last weeks 2 metre thick ice .. sPoof ice .. b.c.

back on the thickness topic and on my proposal to review maps for obvious errors before release.

has been discussed, just a small addendum for those who don't think alike ;)

(even without any special sign i hope that i've interpreted your post as sarcastic, else sorry.

be cause

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Re: 2019 sea ice area and extent data
« Reply #1538 on: July 09, 2019, 09:06:29 PM »
  I like a little irony .. sarcasm I try to leave to others .. b.c.

 p.s.  I suppose I could say 'thank goodness the wind has died down .. the melt season is over .. ' .. but I won't
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

Darvince

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Re: 2019 sea ice area and extent data
« Reply #1539 on: July 10, 2019, 05:07:28 AM »
… DMI shows it right on the line.  Still just a hair above most years it seems.

Note the 'average' line is for 1958-2002 when the Arctic was a different beast.  (Don't ask me how it was 'warmer' then.)  Looking through the archive, you'll see recent years have an occasional bump above the above-0ºC green line segment, but averaging between the zero and the green line.  For 2019's trace to be right on the green line is actually rather spectacular!

[...]

That's something I've wondered previously, as well. Why would the North Pole and nearby have been slightly warmer  in those earlier years, when the ice was thicker?

[...]

As I say, that's just speculation. It could well be another reason. Does anyone know?
IIRC, (no source handy right now unfortunately), because first-year ice is saltier than multi-year ice, it has a lower melting point and so it will begin absorbing heat for melt at a lower temperature than multi-year ice.

DavidR

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Re: 2019 sea ice area and extent data
« Reply #1540 on: July 10, 2019, 05:54:49 AM »
… DMI shows it right on the line.  Still just a hair above most years it seems.

Note the 'average' line is for 1958-2002 when the Arctic was a different beast.  (Don't ask me how it was 'warmer' then.)  Looking through the archive, you'll see recent years have an occasional bump above the above-0ºC green line segment, but averaging between the zero and the green line.  For 2019's trace to be right on the green line is actually rather spectacular!

[...]

That's something I've wondered previously, as well. Why would the North Pole and nearby have been slightly warmer  in those earlier years, when the ice was thicker?

[...]

As I say, that's just speculation. It could well be another reason. Does anyone know?
IIRC, (no source handy right now unfortunately), because first-year ice is saltier than multi-year ice, it has a lower melting point and so it will begin absorbing heat for melt at a lower temperature than multi-year ice.
Would sunlight reflecting off a solid ice pack warm the air more than sunlight being absorbed by the open water between fractured floes?
Toto, I've a feeling we're not in Kansas anymore

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #1541 on: July 10, 2019, 06:15:59 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

July 9th, 2019:
     7,953,297 km2, a century drop of -181,715 km2:o
     2019 is the 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.

Neven

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Re: 2019 sea ice area and extent data
« Reply #1542 on: July 10, 2019, 06:37:31 AM »
According to my spreadsheet, that's the third highest daily drop for July in the 2005-2019 period. 2012 and 2018 had a double century break, both on 24 July.

I do wonder when it starts to level off...
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Darvince

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Re: 2019 sea ice area and extent data
« Reply #1543 on: July 10, 2019, 06:40:04 AM »
Would sunlight reflecting off a solid ice pack warm the air more than sunlight being absorbed by the open water between fractured floes?
No. The surface absorbs the majority of sunlight that the Earth absorbs. Air absorbs little sunlight. Any condition where the air above is warmer than the surface mean warmer air has been imported from elsewhere. Why do you ask?

bbr2314

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Re: 2019 sea ice area and extent data
« Reply #1544 on: July 10, 2019, 06:46:41 AM »
According to my spreadsheet, that's the third highest daily drop for July in the 2005-2019 period. 2012 and 2018 had a double century break, both on 24 July.

I do wonder when it starts to level off...
We still have a lot of ice in Hudson Bay. That is a lot of easy large negative contributions in the near future. This makes the lead over previous years much more impressive and gives 2019 much more leeway IMO.

wdmn

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Re: 2019 sea ice area and extent data
« Reply #1545 on: July 10, 2019, 06:52:09 AM »
According to my spreadsheet, that's the third highest daily drop for July in the 2005-2019 period. 2012 and 2018 had a double century break, both on 24 July.

I do wonder when it starts to level off...

Must be one of the largest three day cumulative drops (for July at least) on record also...? 457,327k

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1546 on: July 10, 2019, 07:02:17 AM »
JAXA ARCTIC EXTENT :-  7,953,297 km2(July 9, 2019)

4 century breaks in a row is serious melting. If it looks like a cliff, then it is a cliff.
One more daily loss like that and time to reach for the hyperbolic dictionary.

- Extent is lowest in the satellite record.
- Extent loss on this day 182 k, 90 k more than the average loss on this day of 92 k.
- Extent loss from maximum 6,318 k, 453 k (7.7%) greater than the average of 5,865 k loss from maximum by this day,
- On average 59.4% of the melting season done, with 66 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 3.94 million km2, 2nd lowest in the satellite record, and 0.76 million km2 above the 2012 low of 3.18 million km2.

The first 9 days in July now certainly greatly above  average area loss.

Other Stuff
Weather
GFS over the next 7 days showing temperature anomalies falling from +1.7 to +0.2 degrees celsius.
- over the Arctic Ocean itself temperatures a bit above average,
- the CAA & Baffin Bay mostly warm,
- Western Canada stays mostly cool.
- Alaska and Eastern Siberian really warm,
- Central Siberia and Western Siberia mostly cool.

Area Loss Outlook
We are now in the period of maximum daily extent loss that lasts until mid or late July and then very gradually declines. Extent loss this month well above average. Immediate weather outlook suggests a cooling of the Arctic

On every measure (JAXA extent, NSIDC daily and 5 day area and extent, and volume), 2019 is now lowest in the satellite record.

To end the season on a record low, remaining extent loss must be more than 20 % above the previous 10 years' average.
For a BOE,  remaining extent loss must be more than 70 % above the previous 10 years' average.

The June volume data persuaded me to drop my minimum guesstimate to below 4 million km2 from exactly 4 million km2. This assumes remaining extent loss will continue at at least at average.
______________________________________________________________
« Last Edit: July 10, 2019, 12:39:48 PM by gerontocrat »
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Nikita

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Re: 2019 sea ice area and extent data
« Reply #1547 on: July 10, 2019, 09:43:01 AM »
- Extent loss on this day 182 k, 92 k more than the average loss on this day of 92 k.

92+92=182?

Steven

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Re: 2019 sea ice area and extent data
« Reply #1548 on: July 10, 2019, 12:22:20 PM »
That's something I've wondered previously, as well. Why would the North Pole and nearby have been slightly warmer  in those earlier years, when the ice was thicker?

I guess it's because the data in that DMI 80N graph is not consistent.

For the climatology they use ECMWF ERA-40 reanalysis data for 1958-2002.  That dataset ends in August 2002.  For the more recent years, they use other datasets (also from ECMWF) with ever better resolution.  I suspect that those are not directly comparable to the ERA-40 baseline, and that this makes recent years biased low in the DMI graph.  But I haven't looked for evidence in the literature.

Of course there's another blatant problem with the DMI graph: it's not properly area-weighted.  That doesn't increase confidence in that graph.

In contrast, NCEP reanalysis suggests that summer temperatures north of 80°N have been substantially higher in recent years than the 1958-2002 average (e.g. see July monthly temperatures north of 80°N).  That is quite different from the DMI graph.

DavidR

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Re: 2019 sea ice area and extent data
« Reply #1549 on: July 10, 2019, 02:14:53 PM »
Would sunlight reflecting off a solid ice pack warm the air more than sunlight being absorbed by the open water between fractured floes?
No. The surface absorbs the majority of sunlight that the Earth absorbs. Air absorbs little sunlight. Any condition where the air above is warmer than the surface mean warmer air has been imported from elsewhere. Why do you ask?
With very  high albedo. corresponding  to fairly solid pack, 90% of the solar radiation is reflected giving it the opportunity to warm the air a second time. With a fragmented pack, as we see now, less radiation is reflected so  the warming of the atmosphere is muted. As a consequence air temperatures with a solid pack may be warmer than with a fragmented pack.
This could explain why summers back in the 40's and 50s were seen as nearly as warm as now in the NOAA-ESRL record.
Toto, I've a feeling we're not in Kansas anymore