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Killian

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Re: 2019 sea ice area and extent data
« Reply #2250 on: August 27, 2019, 03:11:49 PM »
I cannot access the ADS-NIPR (JAXA) page.
I hope they will fix the problem ASAP.

https://ads.nipr.ac.jp/vishop/#/extent

4.37, most likely.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2251 on: August 27, 2019, 03:18:28 PM »
NSIDC Total Area as at 26 August 2019 (5 day trailing average) 2,945,457 km2

Sorry about yesterday - "events, dear boy, events". Can't say it won't happen again.

On this day area loss rose a bit, but area is reducing at a leisurely rate, so the inevitable happened. 2016 Area is now less than 2019

                        
Total Area         
 2,945,457    km2      
-464,240    km2   <   2010's average.
-332,175    km2   <   2018
-1,333,840    km2   <   2000's average.
         
Total Area Change   -26    k   loss
Peripheral Seas   -10    k   loss
Central Seas__   -17    k   loss
Other Seas___    1    k   gain
         
Peripheral Seas         
Bering _______    0    k   gain
Baffin  Bay____   -1    k   loss
Greenland____   -8    k   loss
Barents ______   -1    k   loss
         
CAB Seas         
Beaufort_____   -2    k   loss
CAA_________   -2    k   loss
East Siberian__   -3    k   loss
Central Arctic_   -12    k   loss
         
Kara_________    0    k   gain
Laptev_______    1    k   gain
Chukchi______    0    k   gain
         
Other Seas         
Okhotsk______    0    k   gain
St Lawrence___    -    k   loss
Hudson Bay___    1    k   gain
- Area loss 26 k, 6 k less than the 2010's average area loss of 31 k on this day,
- Total area 3rd Lowest, 33 k MORE than 2016, and 292 k MORE than 2012.

On this day area loss a bit less than 2012 and a lot less than 2016 while NSIDC daily extent loss of 25 k.
________________________________________________________________________
Outlook
We are now well into the period of reducing and very variable daily area loss that that will slide to zero by mid-September.

This late in the season getting back any "shortfall" in area and extent losses is more difficult to get back (it is a matter of arithmetic).

But even so, end of season wobbles makes comments out-of-date almost before they are typed.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)

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2252 on: August 27, 2019, 04:08:05 PM »
Bits & Pieces

Dispersion Has been above and below the 2010's average. Over the years dispersion at minimum has increased significantly, from just over 135% in the 1980s, to nearly 155% in the 2010's. Dispersion was maximum in the two record low minimum years of 2012 and 2016 (assuming 2019 springs no surprises). 

I guess we are talking about a measure of a thinner, more dispersed and mobile remaining ice pack.

The Greenland Sea has finally reacted to the strongish southerly winds in recent days, i.e. blocked export from the Fram and melted quite a lot. A prediction of mine coming true! Wonders never cease. But it looks like very soon the southerly wind shifts east to hug the Norwegian coast, and a counter-wind from the North develops along Greenland's East coast.

But this southerly looks like turning into an easterly to affect the Barents / CAB Atlantic  edge for a few days. Maybe the remains of the Barents will finally melt, and some impact on the CAB?

The Central Arctic Sea (CAB) continues to lose ice below the 2010's average, but not dramatically. Chances of a record-breaker - approaching zero?
"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 #2253 on: August 27, 2019, 05:14:40 PM »
NSIDC ARCTIC SEA ICE EXTENT (5 day trailing average) :- 4,390,697 km2(August 26, 2019)

With me AWOL yesterday and JAXA AWOL today, some of you may be showing signs of data-deprivation stress. So here is an analysis of NSIDC Extent in JAXA format. However, using 5 day trailing averages. I know it is only methadone, not decent grade heroin, but it is the best I can do.


Extent loss has been dismally low for about the last 10 days, but
- Extent is still 2nd lowest in the satellite record,

- Extent is 613 k greater than 2012, 260 k less than 2016.
- Extent loss on this day 13 k, 42 k less than the average loss on this day of 55 k.
- Extent loss from maximum 9,984 k, 457 k (4.8%) greater than the average of 9,527 k loss from maximum by this day,
- Extent loss from maximum to date is also second highest in at least the last 12 years, only second to 2012,
- On average 94.2% of the melting season done, with 18 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining extent loss (0.59 million km) would give a minimum of 4.05 million km2, 2nd lowest in the satellite record, 0.66 million km2 above the 2012 low of 3.39 million km2 and 0.09 million below the 2nd lowest in 2016 of 4.14 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. 

On average, each day now consumes more than 5% of the time available for further extent loss. If, as in 2017 & 2018, extent loss from now was very low, the final minimum could be in 4th place, 2012, 2016 and 2007 being lower..
____________________________________________________________
"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 #2254 on: August 27, 2019, 06:11:53 PM »
NSIDC daily extent

jplotinus

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Re: 2019 sea ice area and extent data
« Reply #2255 on: August 27, 2019, 06:31:25 PM »
Yes, gerentocrat, data deprivation is what I’m experiencing and it couldn’t happen at a worse time as the current end of 2019 melt season. I think I speak for many here in saying thank for supplying NSIDC data in your JAXA format for us today.
😊

jdallen

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Re: 2019 sea ice area and extent data
« Reply #2256 on: August 27, 2019, 11:38:07 PM »
Considering momentum, heat in the water and everything else, the slowdown over the last week is nothing short of astonishing to me.

I really didn't expect to be wrong concluding extent this year would drop under 4 million KM2, but am happy that it appears it won't.

As I said elsewhere, seems there's a factor we are missing somehow.
This space for Rent.

Tigertown

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Re: 2019 sea ice area and extent data
« Reply #2257 on: August 27, 2019, 11:47:37 PM »
Considering momentum, heat in the water and everything else, the slowdown over the last week is nothing short of astonishing to me.

I really didn't expect to be wrong concluding extent this year would drop under 4 million KM2, but am happy that it appears it won't.

As I said elsewhere, seems there's a factor we are missing somehow.

I've been speculating for a while about that. Maybe, the ice is in such a bad condition that mostly volume is being lost at this point and the remaining ice continues to disperse, keeping up with the two-dimensional losses.  Of course, the only way we will know is to wait a couple weeks on  the PIOMAS numbers.

jdallen

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Re: 2019 sea ice area and extent data
« Reply #2258 on: August 27, 2019, 11:50:55 PM »
Considering momentum, heat in the water and everything else, the slowdown over the last week is nothing short of astonishing to me.

I really didn't expect to be wrong concluding extent this year would drop under 4 million KM2, but am happy that it appears it won't.

As I said elsewhere, seems there's a factor we are missing somehow.

I've been speculating for a while about that. Maybe, the ice is in such a bad condition that mostly volume is being lost at this point and the remaining ice continues to disperse, keeping up with the two-dimensional losses.  Of course, the only way we will know is to wait a couple weeks on  the PIOMAS numbers.
Contemplating volume as well.  I may try to hunt down some numbers and see if anything relevant jumps out at me.  If it does, I'll post over on the melt season thread.
This space for Rent.

Killian

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Re: 2019 sea ice area and extent data
« Reply #2259 on: August 28, 2019, 04:43:22 AM »
I cannot access the ADS-NIPR (JAXA) page.

4.37, most likely.

The last three conversions were correct. None of the 10 NSIDC to JAXA conversions are off by more than 30k. 4 are correct, 2 are off by 10k, 2 by 20k, 2 by 30k.

Of the JAXA to NSIDC conversions 4 are correct, 2 are off by 10k, 2 are off by 20k, 1 by 30k, 1 by 40k.


Recent JAXA <-> NSIDC Conversions

                 NSIDC                     NSIDC          5-D -     NSIDC 5D         JAXA -->
                      5-D       JAXA      Daily         JAXA      --> JAXA         NSIDC         
08/16/2019   4.96        4.70      4.90          0.26           4.69               4.98
08/17/2019   4.92        4.63      4.87          0.29           4.66               4.89
08/18/2019   4.89        4.56      4.79          0.33           4.59               4.85
08/19/2019   4.85        4.53      4.76          0.32           4.52               4.86
08/20/2019   4.81        4.51      4.73          0.30           4.49               4.83
08/21/2019   4.77        4.47      4.72          0.30           4.47               4.77
08/22/2019   4.73        4.44      4.63          0.29           4.42               4.74
08/23/2019   4.70        4.41      4.65          0.29           4.41               4.70
08/24/2019   4.68        4.39      4.67          0.29           4.39               4.68
08/25/2019   4.67        4.38      4.68          0.29           4.38               4.67
08/26/2019   4.66                     4.65                           4.37           

                     

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #2260 on: August 28, 2019, 05:45:52 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

August 26th, 2019:
     4,359,151 km2, a drop of -23,322 km2.

August 27th, 2019:
     4,339,067 km2, a drop of -20,084 km2.
     2019 is 2nd lowest on record.
     (2012 & 2016 highlighted).

P.S. I am going to be traveling from Aug 29th to Sept 1st, so I will not post on those days.
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 #2261 on: August 28, 2019, 01:10:17 PM »
JAXA ARCTIC SEA ICE EXTENT :- 4,339,067 km2(August 27, 2019)

JAXA daily extent loss in the last week and very much below average.

- Extent is still 2nd lowest in the satellite record (49 days at lowest this year),
- Extent is 694 k greater than 2012, 126 k less than 2016.
- Extent loss on this day 20 k, 26 k less than the average loss on this day of 46 k.
- Extent loss from maximum 9,932 k, 470 k (5.0%) greater than the average of 9,462 k loss from maximum by this day,
- Extent loss from maximum to date is also second highest in at least the last 12 years, only second to 2012,
- On average 95.8% of the melting season done, with 17 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt (0.57 million km) would give a minimum of 3.92 million km2, 2nd lowest in the satellite record, 0.74 million km2 above the 2012 low of 3.18 million km2 and 0.10 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. 

On average, each day now consumes 6% of the time available for further extent loss. If, as in 2017 & 2018, extent loss from now was very low, the final minimum could be in excess of 4 million km2 in 4th place.
____________________________________________________________
"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)

weatherdude88

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Re: 2019 sea ice area and extent data
« Reply #2262 on: August 28, 2019, 03:02:44 PM »
For 8.27, the NSIDC northern hemisphere sea ice extent value is 4.683 millions of square kilometers. This is an increase of 29,000 square kilometers.

NSIDC sea ice extent is now in third place for the date.

2019 now has 898,000 square kilometers more sea ice extent than 2012, 148,000 square kilometers more sea ice than 2016. 2019 now has 147,000 square kilometers less sea ice than 2007, 155,000 less sea ice than 2011 for the date.

We still have our first candidate for the 2019 northern hemisphere sea ice minimum (historically unprecedented and unlikely for minimum this early). We have seen sea ice extent gains in 4 of the last 5 days in the data set. We are now 55,000 squared kilometers above the August 22nd value.

2019 could fall to 5th place in the next 3 days, if the trend continues.

Klondike Kat

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Re: 2019 sea ice area and extent data
« Reply #2263 on: August 28, 2019, 03:09:17 PM »
For 8.27, the NSIDC northern hemisphere sea ice extent value is 4.683 millions of square kilometers. This is an increase of 29,000 square kilometers.

NSIDC sea ice extent is now in third place for the date.

2019 now has 898,000 square kilometers more sea ice extent than 2012, 148,000 square kilometers more sea ice than 2016. 2019 now has 147,000 square kilometers less sea ice than 2007, 155,000 less sea ice than 2011 for the date.

We have our first candidate for the 2019 northern hemisphere sea ice minimum (historically unprecedented and unlikely for minimum this early). We have seen sea ice extent gains in 4 of the last 5 days in the data set. We are now 55,000 squared kilometers above the August 22nd value.

2019 could fall to 5th place in the next 3 days, if the trend continues.

Wow!  To think that finishing in fifth place is a real possibility after the low extent in early August had many predicting that second was a foregone conclusion and that 2019 might actually challenge 2012 for first.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2264 on: August 28, 2019, 03:36:28 PM »
NSIDC Total Area as at 27 August 2019 (5 day trailing average) 2,937,517 km2

On this day area loss fell to a miserable 8k. If not for area loss in the Greenland Sea - it would have been less than 1 k.
                        
Total Area         
 2,937,517    km2      
-437,247    km2   <   2010's average.
-307,627    km2   <   2018
-1,316,659    km2   <   2000's average.
         
Total Area Change   -8    k   loss
Peripheral Seas   -7    k   loss
Central Seas__   -3    k   loss
Other Seas___    2    k   gain
         
Peripheral Seas         
Bering _______    0    k   gain
Baffin  Bay____    0    k   gain
Greenland____   -7    k   loss
Barents ______   -0    k   loss
         
CAB Seas         
Beaufort_____   -2    k   loss
CAA_________   -1    k   loss
East Siberian__   -1    k   loss
Central Arctic_   -1    k   loss
         
Kara_________   -0    k   loss
Laptev_______    2    k   gain
Chukchi______    0    k   gain
         
Other Seas         
Okhotsk______    1    k   gain
St Lawrence___    -    k   loss
Hudson Bay___    1    k   gain
- Area loss 8 k, 26k less than the 2010's average area loss of 34 k on this day,
- Total area 3rd Lowest, 117 k MORE than 2016, and 311 k MORE than 2012.

On this day area loss a lot less than 2012 and a lot less than 2016 while NSIDC daily extent gain of 29 k, making 4 extent gains in the last 5 days..
________________________________________________________________________
Outlook
We are now well into the period of reducing and very variable daily area loss that that will slide to zero by mid-September.

This late in the season getting back any "shortfall" in area and extent losses is more difficult to get back (it is a matter of arithmetic), and something very odd is going on.

But even so, 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 #2265 on: August 28, 2019, 05:55:29 PM »
NSIDC daily extent

charles_oil

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Re: 2019 sea ice area and extent data
« Reply #2266 on: August 28, 2019, 06:25:29 PM »
Gero:  ....and something very odd is going on.


Wondering what surprise(s) may be in store then.....

Dunno why it went tiny !!!
« Last Edit: August 29, 2019, 10:51:56 AM by charles_oil »

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #2267 on: August 29, 2019, 05:47:31 AM »
August 28th, 2019:
     4,339,440 km2, an increase of 373 km2.
     2019 is 2nd lowest on record.
     (2012 & 2016 highlighted).

P.S. I am going to be traveling from Aug 29th to Sept 1st, so I will not post on those days.
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 #2268 on: August 29, 2019, 10:32:02 AM »
JAXA ARCTIC SEA ICE EXTENT :- 4,339,440 km2(August 28, 2019)

JAXA daily extent loss in the last 2 weeks very much below average and on this day a 373km2 increase. Definitely not a one-off - this is an event.

- Extent is still 2nd lowest in the satellite record,
- Extent is 753 k greater than 2012, 93 k less than 2016.
- Extent loss on this day -0 k, 37 k less than the average loss on this day of 37 k.
- Extent loss from maximum 9,932 k, 433 k (4.6%) greater than the average of 9,499 k loss from maximum by this day,
- Extent loss from maximum to date is still second highest in at least the last 12 years, only second to 2012,
- On average 96.2% of the melting season done, with 16 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt (0.57 million km) would give a minimum of 3.96 million km2, 2nd lowest in the satellite record, 0.78 million km2 above the 2012 low of 3.18 million km2 and 0.06 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. 

On average, each day now consumes 7% of the time available for further extent loss. If, as in 2015, 2017 & 2018, extent loss from now was very low, the final minimum could be in excess of 4.07 million km2 and in 4th place.
____________________________________________________________
"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)

DrTskoul

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Re: 2019 sea ice area and extent data
« Reply #2269 on: August 29, 2019, 11:42:22 AM »
Talk about a left turn !! 2019 took the exit ramp...

Krakatoa

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Re: 2019 sea ice area and extent data
« Reply #2270 on: August 29, 2019, 12:10:43 PM »
A few weeks ago I was sure extend would drop below 4 Million this year. Now that looks very unlikely

weatherdude88

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Re: 2019 sea ice area and extent data
« Reply #2271 on: August 29, 2019, 02:54:33 PM »

For 8.28, the NSIDC northern hemisphere sea ice extent value is 4.662 millions of square kilometers. This is an decrease of 21,000 square kilometers.

NSIDC sea ice extent is still in third place for the date.

2019 now has 904,000 square kilometers more sea ice extent than 2012, 42,000 square kilometers more sea ice than 2016. 2019 now has 31,000 square kilometers less sea ice than 2015, 61,000 square kilometers less sea ice than 2007, and 137,000 square kilometers less sea ice than 2011 for the date.

We still have our first candidate for the 2019 northern hemisphere sea ice minimum (historically unprecedented and unlikely for minimum this early). We have seen sea ice extent gains in 4 of the last 6 days in the data set. We are now 34,000 squared kilometers above the August 22nd value.

2019 could fall to 6th place in the next 2 days, if the trend continues.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2272 on: August 29, 2019, 03:25:51 PM »
NSIDC Total Area as at 28 August 2019 (5 day trailing average) 2,945,583 km2

On this day area increased by 8k. If not for an area loss in the Greenland Sea of 10k- it would have been an increase of 18k, nearly all in the Central Seas.
                        
Total Area         
 2,945,583    km2      
-391,443    km2   <   2010's average.
-266,893    km2   <   2018
-1,288,289    km2   <   2000's average.
         
Total Area Change    8    k   gain
Peripheral Seas   -11    k   loss
Central Seas__    18    k   gain
Other Seas___    2    k   gain
         
Peripheral Seas         
Bering _______   -0    k   loss
Baffin  Bay____   -1    k   loss
Greenland____   -10    k   loss
Barents ______   -1    k   loss
         
CAB Seas         
Beaufort_____   -3    k   loss
CAA_________    1    k   gain
East Siberian__    0    k   gain
Central Arctic_    12    k   gain
         
Kara_________    1    k   gain
Laptev_______    6    k   gain
Chukchi______    0    k   gain
         
Other Seas         
Okhotsk______    0    k   gain
St Lawrence___    -    k   loss
Hudson Bay___    1    k   gain
- Area GAIN 8 k, 43 k different from the 2010's average area LOSS of 35 k on this day,
- Total area 3rd Lowest, 200 k MORE than 2016, and 367 k MORE than 2012.

On this day area change a lot less than 2012 and a lot less than 2016 while NSIDC daily extent loss of 21 k, making it 4 extent gains in the last 6 days..
________________________________________________________________________
Outlook
We are now well into the period of reducing and very variable daily area loss that that will slide to zero by mid-September.

This late in the season getting back any "shortfall" in area and extent losses is more difficult to get back (it is a matter of arithmetic), and something very odd is going on, especially a 5-day trailing average GAIN this early.

But even so, 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)

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2273 on: August 29, 2019, 03:31:01 PM »
Just so you can see a graph of one sea (the Greenland Sea) losing some ice.

Mind you, it look like the wind is changing from South to North & Fram Export will resume shortly.
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Tom_Mazanec

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Re: 2019 sea ice area and extent data
« Reply #2274 on: August 29, 2019, 04:25:48 PM »
Is there any information on what thevolume of ice is?
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MyACIsDying

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Re: 2019 sea ice area and extent data
« Reply #2275 on: August 29, 2019, 05:01:09 PM »
PIOMAS volume provides monthly data, soon... DMI does have a daily tracker. I searched the forum for any comments on its validity and didn't see anything concerning, feel free to correct me.

http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE_combine_thick_SM_EN_20190828.png

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Re: 2019 sea ice area and extent data
« Reply #2276 on: August 29, 2019, 05:15:31 PM »
This year's extent/area might resemble a U curve ...

philopek

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Re: 2019 sea ice area and extent data
« Reply #2277 on: August 29, 2019, 07:02:56 PM »
A few weeks ago I was sure extend would drop below 4 Million this year. Now that looks very unlikely

It will fall below 4M km2 !

The longer the current stall holds, the steeper will be the drop once the responsible weather patterns will change. (if they do which nobody knows for sure)

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Re: 2019 sea ice area and extent data
« Reply #2278 on: August 29, 2019, 07:41:11 PM »
PIOMAS volume provides monthly data, soon... DMI does have a daily tracker. I searched the forum for any comments on its validity and didn't see anything concerning, feel free to correct me.

http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE_combine_thick_SM_EN_20190828.png

I am waiting for this, will help tell us how much of the stall is due to dispersion vs a real stall in melting.

oren

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Re: 2019 sea ice area and extent data
« Reply #2279 on: August 29, 2019, 07:47:37 PM »
DMI is not reliable, especially not this time of year. It tends to have a minimum in late August and starts increasing volume at a time when bottom melt is clearly still going strong.
I am betting PIOMAS will show a slowdown, as it is fed with sea ice concentration (area) data. I think more ice volume is lost in the model when the area disappears. But I am still mighty curious.

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Re: 2019 sea ice area and extent data
« Reply #2280 on: August 29, 2019, 07:54:23 PM »
I am waiting for this, will help tell us how much of the stall is due to dispersion vs a real stall in melting.

I'm curious as well while as i posted elsewhere, is suspect that volume measurements are not accurate enough and depend on extent/area a lot, hence i further suspect that the result for volume will be heavily biased/impacted by the large area and extent numbers, they will perhaps kind of overrule the thickness factor that cannot be measured reliably by now, at least, as far as i know, the latest sat-measurement methods that laser the freeboard do not yet flow into volume calculations.

This is an assumption/speculation/suspicion hence the curiosity but I won't be surprised if volume will be higher as expected as well. In case we see 2 days of dropping area/extent things would be a lot easier.

Very special all this, it's another lesson how little we know ;)

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Re: 2019 sea ice area and extent data
« Reply #2281 on: August 29, 2019, 09:23:28 PM »
NSIDC daily extent

DavidR

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Re: 2019 sea ice area and extent data
« Reply #2282 on: August 30, 2019, 12:58:03 AM »
PIOMAS volume provides monthly data, soon... DMI does have a daily tracker. I searched the forum for any comments on its validity and didn't see anything concerning, feel free to correct me.

http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE_combine_thick_SM_EN_20190828.png

I am waiting for this, will help tell us how much of the stall is due to dispersion vs a real stall in melting.
Biases in PIOMAS are discussed here:
http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/validation/

PIOMAS won't help a lot at this stage because it overstates the volume of thin ice. With more thin ice widely distributed the PIOMAS volume estimate may hold up despite a reality of less ice. The last few days appear to have spread the ice and lowered the concentration which will lead to an increase in the error in the PIOMAS estimate.

As the attached graph shows the over estimate of volume, on ice below 1m thick according to  submarine measurements, could be double what the submarines are seeing.
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mabarnes

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Re: 2019 sea ice area and extent data
« Reply #2283 on: August 30, 2019, 06:58:31 AM »
Since Juan is out ... my humble submission of a less complete pinch hit...:

JAXA Extent for August 29, 2019 - loss of 10,785 square km.
« Last Edit: August 30, 2019, 11:06:55 AM by mabarnes »

binntho

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Re: 2019 sea ice area and extent data
« Reply #2284 on: August 30, 2019, 07:25:19 AM »
I'd just like to add that the current SIE puts 2019 in 4th place, only 2012, 2007 and 2016 have managed to go under 4.33 MKm2 (as far as I can tell ...)
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Feeltheburn

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Re: 2019 sea ice area and extent data
« Reply #2285 on: August 30, 2019, 07:26:34 AM »
Since Juan is out ... my humble submission of an less complete pinch hit...:

You beat out a grounder for a hit!
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Re: 2019 sea ice area and extent data
« Reply #2286 on: August 30, 2019, 08:24:11 AM »
Quote
I'd just like to add that the current SIE puts 2019 in 4th place, only 2012, 2007 and 2016 have managed to go under 4.33 MKm2 (as far as I can tell ...)

According to the JAXA extent data table:
2015 had a minimum of 4,257,003 km² on 9/14 (53,652 km² lower than yesterday)
2011 had a minimum of 4,269,199 km² on 9/10 (59,456 km² lower than yesterday)


Feeltheburn

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Re: 2019 sea ice area and extent data
« Reply #2287 on: August 30, 2019, 08:31:33 AM »
Quote
I'd just like to add that the current SIE puts 2019 in 4th place, only 2012, 2007 and 2016 have managed to go under 4.33 MKm2 (as far as I can tell ...)

According to the JAXA extent data table:
2015 had a minimum of 4,257,003 km² on 9/14 (53,652 km² lower than yesterday)
2011 had a minimum of 4,269,199 km² on 9/10 (59,456 km² lower than yesterday)

I am rooting for 4th but if I were betting I'd say safe at second.
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Re: 2019 sea ice area and extent data
« Reply #2288 on: August 30, 2019, 11:52:19 AM »
JAXA ARCTIC SEA ICE EXTENT :- 4,328,655 km2(August 29, 2019)

JAXA daily extent loss in the last 2 weeks very much below average and on this day up from a -0k extent loss to a below average 11k extent loss. Definitely not a one-off - this is an event.

- Extent is still 2nd lowest in the satellite record,
- Extent is 778 k greater than 2012, 75 k less than 2016.
- Extent loss on this day 11 k, 22 k less than the average loss on this day of 33 k.
- Extent loss from maximum 9,941 k, 411 k (4.3%) greater than the average of 9,532 k loss from maximum by this day,
- Extent loss from maximum to date is still second highest in at least the last 12 years, only second to 2012,
- On average 96.5% of the melting season done, with 15 days to average date of minimum (13 September).

The Perils of Projections.
Average remaining melt (0.35 million km) would give a minimum of 3.98 million km2, 2nd lowest in the satellite record, 0.80 million km2 above the 2012 low of 3.18 million km2 and 0.04 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. 

On average, each day now consumes 7% of the time available for further extent loss.

Given that Arctic temperature anomalies have been consistently above average and that SSTs have been and are very high, this two week stall in extent (and now area) loss is a complete mystery to me.
____________________________________________________________
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2289 on: August 30, 2019, 12:00:31 PM »
Attached is current JAXA extent compared with previous years' minima. and the plume of projections of the minimum from previous years' remaining extent losses.

It still looks likely that the question is how will the 2019 minimum compare with 2016 (4.02 million km2 & 2nd) and 2007 (4.07 million km2 & 3rd).
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weatherdude88

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Re: 2019 sea ice area and extent data
« Reply #2290 on: August 30, 2019, 03:05:51 PM »
For 8.29, the NSIDC northern hemisphere sea ice extent value is 4.647 millions of square kilometers. This is a decrease of 15,000 square kilometers.

NSIDC sea ice extent is now in fourth place for the date.

2019 now has 956,000 square kilometers more sea ice extent than 2012, 140,000 square kilometers more sea ice than 2016, 8,000 square kilometers more sea ice than 2015. 2019 now has 48,000 square kilometers less sea ice than 2007, 69,000 square kilometers less sea ice than 2011 for the date.

We still have our first candidate for the 2019 northern hemisphere sea ice minimum (historically unprecedented and unlikely for minimum this early). We have seen sea ice extent gains in 4 of the last 7 days in the data set. We are now 19,000 squared kilometers above the August 22nd value.

If 2019 does not lose at least 65,000 square kilometers over the next 2 days, we will fall to 6th place for the date.

If 2019 loses more than 65,000 square kilometers of sea ice, but less than 117,000 square kilometers over the next 2 days, we will fall to 5th place for the date.
« Last Edit: August 30, 2019, 03:28:49 PM by weatherdude88 »

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2291 on: August 30, 2019, 03:30:34 PM »
NSIDC Total Area as at 29 August 2019 (5 day trailing average)  2,966,727 km2

On this day area increased by 21k, (by 8k the previous day). If not for an area loss in the Greenland Sea of 11k- it would have been an increase of 32k, nearly all in the Central Arctic Sea (+27k).
                        
Total Area         
 2,966,727    km2      
-339,149    km2   <   2010's average.
-219,086    km2   <   2018
-1,254,465    km2   <   2000's average.
         
Total Area Change    21    k   gain
Peripheral Seas   -12    k   loss
Central Seas__    32    k   gain
Other Seas___    2    k   gain
         
Peripheral Seas         
Bering _______    0    k   gain
Baffin  Bay____   -1    k   loss
Greenland____   -11    k   loss
Barents ______   -1    k   loss
         
CAB Seas         
Beaufort_____   -2    k   loss
CAA_________    2    k   gain
East Siberian__    2    k   gain
Central Arctic_    27    k   gain
         
Kara_________   -1    k   loss
Laptev_______    3    k   gain
Chukchi______    1    k   gain
         
Other Seas         
Okhotsk______    0    k   gain
St Lawrence___    -    k   loss
Hudson Bay___    1    k   gain
- Area GAIN 21 k, 59 k different from the 2010's average area LOSS of 38 k on this day,
- Total area 3rd Lowest, 254 k MORE than 2016, and 431 k MORE than 2012.

NSIDC one day extent manged to drop by a modest 15k.
________________________________________________________________________
Outlook
We are now well into the period of reducing and very variable daily area loss that that will slide to zero by mid-September.

This late in the season getting back any "shortfall" in area and extent losses is more difficult to get back (it is a matter of arithmetic), and something very odd is going on, especially a 5-day trailing average GAIN on two days in a row this early.

But even so, end of season wobbles makes comments out-of-date almost before they are typed.  Just sit back and watch.
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gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2292 on: August 30, 2019, 03:48:07 PM »
Yesterday I posted that the area loss in the Greenland Sea would be short-lived as Fram export was due to resume. Obviously - not yet. (I must stop using stuff from the melting season thread.)

The Central Arctic Sea (CAB) is in growth mode.
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weatherdude88

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Re: 2019 sea ice area and extent data
« Reply #2293 on: August 30, 2019, 04:17:05 PM »
There was a daily NSIDC sea ice area loss of 17,585 square kilometers. The daily value (not 5 day trailing mean) for 8.29 is 2,981,805 (3,010,805 with pole hole adjustment) square kilometers.

Is this a start of the end of the stall?

We are now 104,378 square kilometers above the August 24th lowest value for the 2019 northern hemisphere melting season.




mabarnes

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Re: 2019 sea ice area and extent data
« Reply #2294 on: August 30, 2019, 06:34:43 PM »

JAXA daily extent loss in the last 2 weeks very much below average and on this day up from a -0k extent loss to a below average 11k extent loss. Definitely not a one-off - this is an event.
...
Given that Arctic temperature anomalies have been consistently above average and that SSTs have been and are very high, this two week stall in extent (and now area) loss is a complete mystery to me.
____________________________________________________________

Gerontocrat - I've been keeping an eye on the ENSO index all year, about every day (for a side bet, the usual amount) ... I know the local temperatures seem contra-intuitive as you mentioned, but on a simple "seems" basis, it seems like the heat just shut off as insolation dropped latter half of August, and I can't help but notice the ENSO faded almost in unison with the melt stall.

Correlation implying Causation?  Yeah I know, but as a data-driven scientist (day job), it makes me take note.  So here's my question for an experienced ice tracker - the big melt came from the Pacific side ... so could that be what's "missing" from the late melt, Pacific heat...?  Curious what you think, as I said, I'm rank novice newbie to ice analysis.  Thanks.
« Last Edit: August 30, 2019, 06:58:58 PM by mabarnes »

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Re: 2019 sea ice area and extent data
« Reply #2295 on: August 30, 2019, 06:42:30 PM »
PIOMAS volume provides monthly data, soon... DMI does have a daily tracker. I searched the forum for any comments on its validity and didn't see anything concerning, feel free to correct me.

http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE_combine_thick_SM_EN_20190828.png
I am waiting for this, will help tell us how much of the stall is due to dispersion vs a real stall in melting.
Biases in PIOMAS are discussed here:
http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/validation/

PIOMAS won't help a lot at this stage because it overstates the volume of thin ice. With more thin ice widely distributed the PIOMAS volume estimate may hold up despite a reality of less ice. The last few days appear to have spread the ice and lowered the concentration which will lead to an increase in the error in the PIOMAS estimate.

As the attached graph shows the over estimate of volume, on ice below 1m thick according to  submarine measurements, could be double what the submarines are seeing.

As long as the methodology of PIOMAS is consistent, it should be fine for comparison.  The operative comparison is not between model and reality, it's between model and previous years' model results. The r-squared ain't that bad. eh. 

Point is adjusting the previous years' model estimators to observed values, if done uniformly, wouldn't change any ratios.  It sure would change the estimate of latent heat of the entire ice mass, tho - so there is that.  Just my 2 cents....

philopek

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Re: 2019 sea ice area and extent data
« Reply #2296 on: August 30, 2019, 07:02:36 PM »
As long as the methodology of PIOMAS is consistent, it should be fine for comparison.  The operative comparison is not between model and reality, it's between model and previous years' model results. The r-squared ain't that bad. eh. 

Usually that's what most of us would say but in this case I disagree because conditions, especially the state of the ice so so entirely different and has been changing over the last few years so much, that, even though the methodology remained the same, it won't produce a a comparable result IMO.

Almost half of the remaining ice is at around 25-75% concentration and the thickness is the big question mark that is responsible for most of the shortcomings of current volume measurement methods.

This means that the error margin has "increased", it's not static and therefore we cannot really compare at this time of the year, that might be different during the winter (freezing season where the gap between algorithms and reality is way smaller, no melt ponds, fractures are either filled with ice or very much distinguished as leads.

Truth of all this will come to light at one day in the future when thickness "surprisingly" will reach zero more or less over half of the extent. A bit an extreme that probably won't happen over night the way I describe it but it can and probably well happen on a large scale over a 1-3 weeks period and since thickness assessment in on the centimeter scale is currently not possible (reliably) we can't make even educated guesses how far we are away from this point.

Considering that most of the ice is first year ice by now, I assume that we are not that far away which is why a major storm will most probably finish most of the dispersed ice, leaving a few thick floes only.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #2297 on: August 30, 2019, 07:10:14 PM »

JAXA daily extent loss in the last 2 weeks very much below average and on this day up from a -0k extent loss to a below average 11k extent loss. Definitely not a one-off - this is an event.
...
Given that Arctic temperature anomalies have been consistently above average and that SSTs have been and are very high, this two week stall in extent (and now area) loss is a complete mystery to me.
____________________________________________________________

Gerontocrat - I've been keeping an eye on the ENSO index all year, about every day (for a side bet, the usual amount) ... I know the local temperatures seem contra-intuitive as you mentioned, but on a simple "seems" basis, it seems like the heat just shut off as insolation dropped latter half of August, and I can't help but notice the ENSO faded almost in unison with the melt stall.

Correlation implying Causation?  Yeah I know, but as a data-driven scientist (day job), it makes me take note.  So here's my question for an experienced ice tracker - the big melt came from the Pacific side ... so could that be what's "missing" from the late melt, Pacific heat...?  Curious what you think, as I said, I'm rank novice newbie to ice analysis.  Thanks.
I can see evidence for Arctic Sea Ice losses not being above average.
What I can't see (given +ve SST and air temp anomalies) is the evidence to show why area and extent losses should be so much below average (with unusual increases on occasion).

But there is anything between 10 and 25 days left in which to chew our fingernails and watch our pet theories/speculations crash and burn.
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binntho

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Re: 2019 sea ice area and extent data
« Reply #2298 on: August 31, 2019, 07:35:58 AM »
Don't know how to get the exact numbers, but seems to be a ~30.000 km2 drop today - bouncing off the 2016 curve?
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zufall

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Re: 2019 sea ice area and extent data
« Reply #2299 on: August 31, 2019, 08:18:32 AM »
https://ads.nipr.ac.jp/vishop/#/extent

Aug 30 extent: 4,302,087 km², down 26,568 km² from Aug 29.