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Neven

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Re: 2019 sea ice area and extent data
« Reply #2100 on: August 11, 2019, 11:25:39 PM »
Shouldn't this discussion be on the main melting thread?

Yes.
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Sterks

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Re: 2019 sea ice area and extent data
« Reply #2101 on: August 11, 2019, 11:34:53 PM »
Shouldn't this discussion be on the main melting thread?

Yes.
Well, in the main thread there's this idiot prosecuting me for being politically conservative (which by the way it is not the topic if I am conservative or liberal in the MELTING SEASON thread, or in this thread).

Would you please do something so that this guy does not, literally, try to bully me?
Shouldn't he be speaking away of politics in these threads anyway?
Thanks in advance.

TeaPotty

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Re: 2019 sea ice area and extent data
« Reply #2102 on: August 12, 2019, 12:12:43 AM »
Shouldn't this discussion be on the main melting thread?

Yes.
Well, in the main thread there's this idiot prosecuting me for being politically conservative (which by the way it is not the topic if I am conservative or liberal in the MELTING SEASON thread, or in this thread).

Would you please do something so that this guy does not, literally, try to bully me?
Shouldn't he be speaking away of politics in these threads anyway?
Thanks in advance.

Poor thing, so many people and facts proving your spam posts wrong.
It must be terribly overwhelming for you... having to face reality like the rest of us.

bill kapra

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Re: 2019 sea ice area and extent data
« Reply #2103 on: August 12, 2019, 01:05:55 AM »
Science isn’t liberal or conservative and I take refuge in this thread because it’s focused on the data (and analysis). Hope it stays that way.

Sterks

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Re: 2019 sea ice area and extent data
« Reply #2104 on: August 12, 2019, 02:09:17 AM »
I'd be extremely surprised if there was any refreeze this early. This requires sustained low temps, often initial refreeze occurs at -10C. I am quite certain this was an AMSR2 artifact.
I was talking about pond refreezing, not ocean refreezing.

FishOutofWater

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Re: 2019 sea ice area and extent data
« Reply #2105 on: August 12, 2019, 03:07:08 AM »
The ponds drain and when the sun angle gets at it's lowest or twilight comes, depending on location, the exposed ice surface firms up. That's what happens after 10 August in much of the Arctic. There's still a shockingly high amount of heat in the ocean and temperatures are still, on average above freezing.

The warm air advection is keeping the ocean temperatures well above normal and when winds, waves and ice motion causes the warm water to interact with the ocean water, ice melting continues at a good clip.

This summer may be worse than 2012 for the long term condition of the ice because heat is building up in the mid levels of the Arctic ocean, not being extracted by a long lived intense storm.

Interpretation of area and extent data is difficult when the Arctic is so cloudy. We are likely seeing the effects of cloud artifacts. The draining of melt ponds and compaction has caused NSIDC area measurements to stall, but that doesn't mean that melting has stopped.
« Last Edit: August 12, 2019, 03:33:13 AM by FishOutofWater »

jdallen

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Re: 2019 sea ice area and extent data
« Reply #2106 on: August 12, 2019, 05:05:40 AM »
I'd be extremely surprised if there was any refreeze this early. This requires sustained low temps, often initial refreeze occurs at -10C. I am quite certain this was an AMSR2 artifact.
I was talking about pond refreezing, not ocean refreezing.
That's how I interpreted you.

That would translate as area increases.
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Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #2107 on: August 12, 2019, 05:42:23 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

August 11th, 2019:
     5,000,009 km2, a century drop of -106,594 km2.
     2019 is 2nd lowest on record.
     (2012 highlighted).
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

petm

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Re: 2019 sea ice area and extent data
« Reply #2108 on: August 12, 2019, 06:38:47 AM »
Looks like we are about a week ahead of the 'other' years (3rd+ place)?

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2109 on: August 12, 2019, 07:23:48 AM »
JAXA ARCTIC EXTENT :-  5,000,009 km2(August 11, 2019)

JAXA daily extent loss on this day was again well above average, yet another century break.

- Extent is 2nd lowest in the satellite record (after 49 days at lowest this year),
- Extent is 112 k above 2012, 494 k below 2016.
- Extent loss on this day 107 k, 42 k more than the average loss on this day of 65 k.
- Extent loss from maximum 9.271 k, 716 k (8.4%) greater than the average of 8,556 k loss from maximum by this day,
- On average 86.6% of the melting season done, with 33 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt would give a minimum of 3.68 million km2, 2nd lowest in the satellite record, 0.50 million km2 above the 2012 low of 3.18 million km2 and 0.34 million below the 2nd lowest in 2016 of 4.02 million km2.

Ice Melt Outlook The peak days of daily melt are past. From now to minimum, on average daily extent loss will gradually reduce until the minimum. 

GFS 5 day weather outlook Again, almost no change
- Central Siberia looks very warm, with the warmth spread to the far east and Alaska
- A band of cold weather from Western Canada to the south of Hudson Bay,
- Northern Greenland, Baffin Bay and the CAA still warm - with occasional rain on the CAA. 
- Southern Greenland below average temperatures.
- A low centered over Novaya Zemla bringing southerly winds from a very warm Siberia may push warmth and even rain across the Arctic Ocean. and then winds from the central arctic towards the Barents.
- And once again it looks like there will be not much export of ice down the Fram into the Greenland Sea.
____________________________________________________________
To be a record low, remaining melt needs to be 40% above the average. No year has ever done this from this late date in the season - not even 2012.

The average projection, being less than 3.75, is down one bin, and may threaten to go down one more.

JAXA daily loss is staying strong, in contrast with the  8, 9 & 10 Aug NSIDC Area data.
Was the NSIDC data on those days an aberration or is compaction real and continuing ?
There is certainly warmth around, both in the air and the sea. I wonder how much this run of very high extent losses is due to that and how much to the poor condition of the ice.
"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 #2110 on: August 12, 2019, 03:33:20 PM »
NSIDC Total Area as at 11 August 2019 (5 day trailing average)  3,490,982 km2

On this day area loss increased but still low
                        
Total Area         
 3,490,982    km2      
-452,362    km2   <   2010's average.
-437,188    km2   <   2018
-1,270,771    km2   <   2000's average.
         
Total Area Change   -43    k   loss
Peripheral Seas   -1    k   loss
Central Seas__   -43    k   loss
Other Seas___    1    k   gain
         
Peripheral Seas         
Bering _______    0    k   gain
Baffin  Bay____   -1    k   loss
Greenland____   -1    k   loss
Barents ______    0    k   gain
         
CAB Seas         
Beaufort_____   -8    k   loss
CAA_________    2    k   gain
East Siberian__   -14    k   loss
Central Arctic_   -10    k   loss
         
Kara_________   -1    k   loss
Laptev_______   -9    k   loss
Chukchi______   -4    k   loss
         
Other Seas         
Okhotsk______   -0    k   loss
St Lawrence___    -    k   loss
Hudson Bay___    1    k   gain
- Area loss 43 k, 5 k LESS than the 2010's average area loss of 48 k on this day.
- Total area 2nd Lowest, 141 k LESS than 2016, and 365 k MORE than 2012.

Outlook
We are now in the period of reducing and very variable daily area loss that that will slide to zero by mid-September.
________________________________________________________________________
End of season wobbles makes comments out-of-date almost before they are typed. Just sit back and watch.
"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)

Shared Humanity

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Re: 2019 sea ice area and extent data
« Reply #2111 on: August 12, 2019, 03:41:28 PM »
The accelerating losses in extent with the continued stubbornly slow losses in area suggests to me that the melt is picking off the easy ice on the periphery while struggling with the more compact ice in the pack. 2nd place is likely the lowest we will go as that easy ice disappears.

oren

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Re: 2019 sea ice area and extent data
« Reply #2112 on: August 12, 2019, 03:43:01 PM »
Finally, a slowdown in basin area, just as 2012 overshot the trends. Hopefully, this is not a measurement artefact and will translate to a slowdown in basin extent.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2113 on: August 12, 2019, 03:46:18 PM »
Here are 4 seas that still seem to be reducing area at a good clip
"Para a Causa do Povo a Luta Continua!"
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Sterks

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Re: 2019 sea ice area and extent data
« Reply #2114 on: August 12, 2019, 04:34:23 PM »
The accelerating losses in extent with the continued stubbornly slow losses in area suggests to me that the melt is picking off the easy ice on the periphery while struggling with the more compact ice in the pack. 2nd place is likely the lowest we will go as that easy ice disappears.
Agree

Alphabet Hotel

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Re: 2019 sea ice area and extent data
« Reply #2115 on: August 12, 2019, 05:22:43 PM »
NSIDC daily extent

Pavel

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Re: 2019 sea ice area and extent data
« Reply #2116 on: August 12, 2019, 05:29:15 PM »
2nd place is likely at minimum but this year most probably will take the lead again in the fall due to the AWP and the extra ocean heat accumulated. 2019 is very bad year in the long term ice loss.

Rich

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Re: 2019 sea ice area and extent data
« Reply #2117 on: August 12, 2019, 06:05:35 PM »
The accelerating losses in extent with the continued stubbornly slow losses in area suggests to me that the melt is picking off the easy ice on the periphery while struggling with the more compact ice in the pack. 2nd place is likely the lowest we will go as that easy ice disappears.
Agree

Hmm. If we look carefully at the area #'s and realize it's a 5 day average then there may be more momentum in the CAB at present than meets the eye.

The CAB has gone from 21k+ gain to 9k+ loss in 2 days, a swing of over 30k. Multiply that by 5 and you have 150k difference in the last 2 days vs. the 2 days that most recently left the 5 day average.

If momentum stay strong the next few days, then 2019 maintains a punchers chance at a record.

Agree completely that 2nd or 3rd is most likely outcome re: area, but the below average area loss today is misleading due to the 5 day average thing.
There's a bit more momentum than that at the moment.

FishOutofWater

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Re: 2019 sea ice area and extent data
« Reply #2118 on: August 12, 2019, 08:34:31 PM »
Those extra thick lightening producing clouds and smoke clouds are holding the ice together well on the NSIDC maps. In other words, ignore the exaggerated day to day variability in the NSIDC data. It's noise.

Stephan

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Re: 2019 sea ice area and extent data
« Reply #2119 on: August 12, 2019, 10:26:32 PM »
I think this is one of the reasons gerontocrat uses the 5 day trailing average. Otherwise we may debate one day about a double century drop, followed by high increases the days after or vice versa. Smoothing and averaging is a wise thing to do with extent, area or volume of sea ice.

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #2120 on: August 13, 2019, 05:40:41 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

August 12th, 2019:
     4,913,209 km2, a drop of -86,800 km2.
     2019 is 2nd lowest on record.
     (2012 highlighted).
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

interstitial

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Re: 2019 sea ice area and extent data
« Reply #2121 on: August 13, 2019, 07:57:36 AM »

Finally, a slowdown in basin area, just as 2012 overshot the trends. Hopefully, this is not a measurement artefact and will translate to a slowdown in basin extent.

The 25 km and 10 km area have paused or are going up while the 1 km area continues down. To me that suggests that the main pack is spreading with new gaps opening up. Overall I think that suggests substantial melt is still occurring even if we can't see it in the extent numbers.  In my opinion the more area that has "rubble" the harder it is to tell how much real melting is occurring.   

VeganPeaceForAll

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Re: 2019 sea ice area and extent data
« Reply #2122 on: August 13, 2019, 08:47:38 AM »
Finally, a slowdown in basin area, just as 2012 overshot the trends. Hopefully, this is not a measurement artefact and will translate to a slowdown in basin extent.

If you look at petm's concentration maps you can see that there is still a strong melt momentum throughout the whole basin.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2123 on: August 13, 2019, 10:17:49 AM »
JAXA ARCTIC EXTENT :-  4,913,209 km2(August 12, 2019)

JAXA daily extent loss on this day was again well above average.

- Extent is 2nd lowest in the satellite record (after 49 days at lowest this year),
- Extent is 120 k greater than 2012, 507 k less than 2016.
- Extent loss on this day 87 k, 15 k more than the average loss on this day of 72 k.
- Extent loss from maximum 9.358 k, 731 k (8.5%) greater than the average of 8,627 k loss from maximum by this day,
- On average 87.3% of the melting season done, with 32 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt (1.25 million km) would give a minimum of 3.66 million km2, 2nd lowest in the satellite record, 0.48 million km2 above the 2012 low of 3.18 million km2 and 0.36 million below the 2nd lowest in 2016 of 4.02 million km2.

Ice Melt Outlook The peak days of daily melt are past. From now to minimum, on average daily extent loss will gradually reduce until the minimum. 

GFS 5 day weather outlook Again, almost no change
- Central Siberia looks very warm, with the warmth spread to the far east and Alaska
- A band of cold weather from Western Canada to the south of Hudson Bay,
- Northern Greenland, Baffin Bay and the CAA still warm. 
- Southern Greenland below average temperatures.
- A low centered over FJL / Svalbard bringing southerly winds from a very warm Siberia may push wind warmth and even rain across the Arctic Ocean. and then winds from the central arctic towards the Barents and away from the NE corner of Greenland before turning south down to Iceland.
____________________________________________________________
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"Damn, I wanted to see what happened next" (Epitaph)

Phil42

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Re: 2019 sea ice area and extent data
« Reply #2124 on: August 13, 2019, 12:51:52 PM »
With yesterdays melt of 87k, even the melt trajectory of 2017 (which was the year with the least melt from this point in time to the minimum since 2007) would result in a minimum below 4M km2.

be cause

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Re: 2019 sea ice area and extent data
« Reply #2125 on: August 13, 2019, 01:04:38 PM »
 .. indeed Phil42 .. and in the 1980's there was 60.5 % more ice in the Arctic than today by this measure .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

Pavel

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Re: 2019 sea ice area and extent data
« Reply #2126 on: August 13, 2019, 01:05:17 PM »
120k is not a big difference with 2012 and it may decrease tomorrow. Quick extent drop can continue due to the Laptev bite and compaction on the Atlantic side

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2127 on: August 13, 2019, 03:31:08 PM »
NSIDC Total Area as at 12 August 2019 (5 day trailing average)  3,456,343 km2

On this day area loss low
                        
Total Area         
 3,456,343    km2      
-449,769    km2   <   2010's average.
-407,530    km2   <   2018
-1,253,290    km2   <   2000's average.
         
Total Area Change   -35    k   loss
Peripheral Seas    4    k   gain
Central Seas__   -38    k   loss
Other Seas___   -1    k   loss
         
Peripheral Seas         
Bering _______    0    k   gain
Baffin  Bay____    1    k   gain
Greenland____    3    k   gain
Barents ______    0    k   gain
         
CAB Seas         
Beaufort_____   -9    k   loss
CAA_________    2    k   gain
East Siberian__   -10    k   loss
Central Arctic_   -7    k   loss
         
Kara_________    0    k   gain
Laptev_______   -10    k   loss
Chukchi______   -4    k   loss
         
Other Seas         
Okhotsk______   -0    k   loss
St Lawrence___    -    k   loss
Hudson Bay___   -1    k   loss
- Area loss 35 k, 8 k LESS than the 2010's average area loss of 43 k on this day,
- Total area 2nd Lowest, 163 k LESS than 2016, and 346 k MORE than 2012.
________________________________________________________________________
Outlook
We are now well into in the period of reducing and very variable daily area loss that that will slide to zero by mid-September.

End of season wobbles makes comments out-of-date almost before they are typed. Just sit back and watch.
"Para a Causa do Povo a Luta Continua!"
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Rich

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Re: 2019 sea ice area and extent data
« Reply #2128 on: August 13, 2019, 07:25:12 PM »
73% of the remaining area is in the CAB at the moment.

I'm guessing that figure has never historically reached as high as 85%, but it's possible this year if the CAA poofs out.

Alphabet Hotel

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Re: 2019 sea ice area and extent data
« Reply #2129 on: August 13, 2019, 08:04:50 PM »
NSIDC daily extent

Shared Humanity

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Re: 2019 sea ice area and extent data
« Reply #2130 on: August 13, 2019, 08:38:02 PM »
With regards to SIE, 2019 has decided to hang out with 2012 rather than move back to the pack.

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #2131 on: August 14, 2019, 05:44:56 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

August 13th, 2019:
     4,820,124 km2, a drop of -93,085 km2.
     2019 is 2nd lowest on record.
     (2012 highlighted).
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2132 on: August 14, 2019, 11:19:17 AM »
JAXA ARCTIC SEA ICE EXTENT :-  4,820,124 km2(August 13, 2019)

JAXA daily extent loss on this day was again well above average.

- Extent is 2nd lowest in the satellite record (after 49 days at lowest this year),
- Extent is 106 k greater than 2012, 564 k less than 2016.
- Extent loss on this day 93 k, 21 k more than the average loss on this day of 72 k.
- Extent loss from maximum 9.451 k, 752 k (8.6%) greater than the average of 8,699k loss from maximum by this day,
- On average 88.0% of the melting season done, with 31 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt (1.18 million km) would give a minimum of 3.64 million km2, 2nd lowest in the satellite record, 0.46 million km2 above the 2012 low of 3.18 million km2 and 0.38 million below the 2nd lowest in 2016 of 4.02 million km2.

Ice Melt Outlook The peak days of daily melt are past. From now to minimum, on average daily extent loss will gradually reduce until the minimum. 

GFS 5 day weather outlook Again, almost no change...
- Nearly all of Siberia looks very warm,
- A band of cold weather persists from Western Canada to the south of Hudson Bay ,
- Northern Greenland, Baffin Bay and the CAA still warm. 
- Southern Greenland below average temperatures.
- A low centered over Svalbard bringing southerly winds from a very warm Siberia may push wind warmth and even rain across the Arctic Ocean. and then winds from the central arctic towards the Barents and away from the NE corner of Greenland before turning south down to Iceland.
____________________________________________________________
"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)

be cause

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Re: 2019 sea ice area and extent data
« Reply #2133 on: August 14, 2019, 02:02:49 PM »
so we have already gained 100 K on 2012 in the last few days .. my original projection a few weeks ago had 2019 regaining the lead on the 16th .. this continues to be possible . b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2134 on: August 14, 2019, 02:03:10 PM »
As it is 31 days, one month to the 10 year average minimum date**, here are some extras.

ARC5:- The plume of projection from remaining extent loss of the last 10 years, all below 4 million km2..

ARC6:- Table showing that if extent loss stopped now, 2019 would be 11th lowest since 1979.

ARC8:- Table of daily extent losses from now to minimum in selected years (for those who like numbers)

ARC7:- 365 trailing daily average - that could be at a record lows again in early 2020.

____________________________________________________________________
** The minimum will be on 13th September. I have said it, and so it is thus.

"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 #2135 on: August 14, 2019, 03:15:42 PM »
NSIDC Total Area as at 13 August 2019 (5 day trailing average)   3,387,596  km2

For once, on this day area loss much ABOVE average
                        
Total Area         
 3,387,596    km2      
-486,404    km2   <   2010's average.
-411,286    km2   <   2018
-1,270,914    km2   <   2000's average.
         
Total Area Change   -69    k   loss
Peripheral Seas    1    k   gain
Central Seas__   -68    k   loss
Other Seas___   -2    k   loss
         
Peripheral Seas         
Bering _______    0    k   gain
Baffin  Bay____   -1    k   loss
Greenland____    2    k   gain
Barents ______    0    k   gain
         
CAB Seas         
Beaufort_____   -10    k   loss
CAA_________   -6    k   loss
East Siberian__   -8    k   loss
Central Arctic_   -26    k   loss
         
Kara_________   -2    k   loss
Laptev_______   -13    k   loss
Chukchi______   -3    k   loss
         
Other Seas         
Okhotsk______   -0    k   loss
St Lawrence___    -    k   loss
Hudson Bay___   -1    k   loss
- Area loss 69 k, 32 k MORE than the 2010's average area loss of 37 k on this day,
- Total area 2nd Lowest, 220 k LESS than 2016, and 299 k MORE than 2012.

On this day area loss much greater than in both 2012 and 2016
________________________________________________________________________
Outlook
We are now well into in the period of reducing and very variable daily area loss that that will slide to zero by mid-September.

End of season wobbles makes comments out-of-date almost before they are typed. Just sit back and watch.
"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)

Alphabet Hotel

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Re: 2019 sea ice area and extent data
« Reply #2136 on: August 14, 2019, 03:25:11 PM »
NSIDC daily extent

sailor

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Re: 2019 sea ice area and extent data
« Reply #2137 on: August 14, 2019, 03:45:42 PM »
Area now facing 2016's long GAC and "Garlic Press" too. The 2nd in extent is almost secured, not the 2nd in area.
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2138 on: August 14, 2019, 03:57:09 PM »
There is just one month to the average date of the Arctic Sea Ice minimum.
So I've brought out of storage the analysis of NSIDC area data using the same layout as the postings for JAXA Extent data


NSIDC ARCTIC SEA ICE AREA (5 day trailing average):-   3,387,596 Km2(August 13, 2019)

NSIDC  daily area loss on this day was well above average.

- Area loss from maximum 9,736 k, 553 k (6.0%) greater than the average of 9,183 k loss from maximum by this day,
- On average 91.6% of the melting season done, with 31 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining AREA loss (0.84 million km) would give a minimum of 2.55 million km2, 3rd lowest in the satellite record, 0.30 million km2 above the 2012 low of 2.25 million km2 and 0.10 million above the 2nd lowest in 2016 of 2.45 million km2.

Ice Melt Outlook 2016 is the one to watch for area loss from now, nearly 40% above  average.
____________________________________________________________
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

sja45uk

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Re: 2019 sea ice area and extent data
« Reply #2139 on: August 14, 2019, 05:27:39 PM »
There is just one month to the average date of the Arctic Sea Ice minimum.
So I've brought out of storage the analysis of NSIDC area data using the same layout as the postings for JAXA Extent.

On the NSIDC-Tot-2.png, would it be possible to see the 'Average Daily Change of Previous 10 Years' and the 'Polynomial (Average Daily Change of Previous 10 Years)' as well as the Average & Polynomial for the last 10 years to better understand what is happening?
[EDIT]
In addition, it might be interesting to have a nowcast with some commentary on the current trend as a companion to the graphs to put their behaviour in context. Forecasts are obviously interesting (but unreliable), and harder to match to the actual behaviour.
« Last Edit: August 14, 2019, 06:01:42 PM by sja45uk »

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2140 on: August 14, 2019, 05:44:44 PM »
There is just one month to the average date of the Arctic Sea Ice minimum.
So I've brought out of storage the analysis of NSIDC area data using the same layout as the postings for JAXA Extent.

On the NSIDC-Tot-2.png, would it be possible to see the 'Average Daily Change of Previous 10 Years' and the 'Polynomial (Average Daily Change of Previous 10 Years)' as well as the Average & Polynomial for the last 10 years to better understand what is happening?
That's what it is, i.e. 'Average Daily Change of Previous 10 Years' and the 'Polynomial (Average Daily Change of Previous 10 Years)' as it says on the labels aon the bottom of the graph.
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"Damn, I wanted to see what happened next" (Epitaph)

sja45uk

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Re: 2019 sea ice area and extent data
« Reply #2141 on: August 14, 2019, 06:06:45 PM »
Sorry, I obvious was not clear. I meant for the years 1999-2008 as well as the years 2009-2018.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2142 on: August 14, 2019, 07:18:06 PM »
Sorry, I obvious was not clear. I meant for the years 1999-2008 as well as the years 2009-2018.
The graphs are intentionally sparse of data to avoid too many trees when looking at the forest.
Also, this thread is the current season only, which is close to the end, and is often erratic. Projections / forecasts even more unreliable.

I occasionally go into longer-term mode, but go to the When will the Arctic be Ice-Free? thread where speculation is not only permitted but encouraged.

Also I am somewhat over-committed at the moment.

Sorry, but ....
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

sja45uk

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Re: 2019 sea ice area and extent data
« Reply #2143 on: August 15, 2019, 01:20:26 AM »
Thanks for the reply, I was just trying to understand how the latest Decadal Average had shifted with respect to the previous decade and whether the polynomials looked similar. I will try and find the answers in the subject area you mentioned.

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #2144 on: August 15, 2019, 05:40:36 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

August 14th, 2019:
     4,768,552 km2, a drop of -51,572 km2.
     2019 is 2nd lowest on record.
     (2012 highlighted).
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2145 on: August 15, 2019, 06:47:05 AM »
JAXA ARCTIC SEA ICE EXTENT :- 4,768,552 km2(August 14, 2019)

JAXA daily extent loss on this day was below average.

- Extent is 2nd lowest in the satellite record (49 days at lowest this year),
- Extent is 118 k greater than 2012, 566 k less than 2016.
- Extent loss on this day 51 k, 10 k less than the average loss on this day of 61 k.
- Extent loss from maximum 9.503 k, 742 k (8.5%) greater than the average of 8,760k loss from maximum by this day,
- On average 88.7% of the melting season done, with 30 days to average date of minimum (13 September).
- if extent loss ceased today 2019 would be the 10th lowest minimum in the satellite record.

The Perils of Projections.
Average remaining melt (1.18 million km) would give a minimum of 3.65 million km2, 2nd lowest in the satellite record, 0.47 million km2 above the 2012 low of 3.18 million km2 and 0.37 million below the 2nd lowest in 2016 of 4.02 million km2.

Ice Melt Outlook The peak days of daily melt are past. From now to minimum, on average daily extent loss will gradually but erratically reduce until the minimum. 

GFS 5 day weather outlook Again, almost no change...
- Nearly all of Siberia looks very warm,
- A band of cold weather persists from Western Canada to the south of Hudson Bay ,
- Northern Greenland, Baffin Bay and the CAA still warm. 
- Southern Greenland below average temperatures.
A low centered over Svalbard is combined combined with a high centred over the ESS
- this brings strong southerly winds from a very warm Siberia may push wind warmth and even rain across the central Arctic Ocean.

And then these strong winds exit the central arctic
-  eastwards towards the Barents away from the NE corner of Greenland before turning south down to Iceland,
- and another branch heads parallel to the CAA / Beaufort crack pushing ice in the Beaufort towards the Alaska shore (to die?).

GFS seems to suggest these winds moderate after a few days.
____________________________________________________________

"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2146 on: August 15, 2019, 03:20:02 PM »
NSIDC Total Area as at 14 August 2019 (5 day trailing average)   3,387,596  km2

On this day area loss extremely ABOVE average
Rate of loss nearly tripled in 2 days, and nearly triple the 2010's average daily loss for this day.

                        
Total Area         
 3,294,777    km2      
-552,866    km2   <   2010's average.
-450,791    km2   <   2018
-1,320,179    km2   <   2000's average.
         
Total Area Change   -93    k   loss
Peripheral Seas    1    k   gain
Central Seas__   -93    k   loss
Other Seas___   -1    k   loss
         
Peripheral Seas         
Bering _______    0    k   gain
Baffin  Bay____   -1    k   loss
Greenland____    3    k   gain
Barents ______   -0    k   loss
         
CAB Seas         
Beaufort_____   -9    k   loss
CAA_________   -7    k   loss
East Siberian__   -3    k   loss
Central Arctic_   -58    k   loss
         
Kara_________   -2    k   loss
Laptev_______   -11    k   loss
Chukchi______   -2    k   loss
         
Other Seas         
Okhotsk______    0    k   gain
St Lawrence___    -    k   loss
Hudson Bay___   -1    k   loss
- Area loss 93 k, 61 k MORE than the 2010's average area loss of 32 k on this day,
- Total area 2nd Lowest, 287 k LESS than 2016, and 224 k MORE than 2012.

On this day area loss very much greater than in both 2012 and 2016
while NSIDC daily extent gained 4k.
________________________________________________________________________
Outlook
We are now well into in the period of reducing and very variable daily area loss that that will slide to zero by mid-September.

End of season wobbles makes comments out-of-date almost before they are typed. Just sit back and watch.

BUT SEE NEXT POST (OR TWO)
"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)

AndyW

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Re: 2019 sea ice area and extent data
« Reply #2147 on: August 15, 2019, 03:23:15 PM »
How many JAXA above 100k per day melts, so far, has 2019 got compared to 2012  and 2007?


gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2148 on: August 15, 2019, 03:36:34 PM »
The daily area loss today was extreme.
So I've brought out of storage again the analysis of NSIDC area data using the same layout as the postings for JAXA Extent data


NSIDC ARCTIC SEA ICE AREA (5 day trailing average):-    3,294,777  Km2(August 14, 2019)

NSIDC  daily area loss on this day was extremely above average.

Daily area loss rose from 36 k to 93 k in 2 days. Using 5 day trailing averages is supposed to iron out erratic extreme variations. The daily loss graph attached shows how 2019 is nearly matching 2012's extremes without a GAC to help it along.

This suggests the state of the ice is a complete mess.

"Para a Causa do Povo a Luta Continua!"
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Alphabet Hotel

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Re: 2019 sea ice area and extent data
« Reply #2149 on: August 15, 2019, 04:33:27 PM »
NSIDC daily extent