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gerontocrat

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Re: Global sea ice area and extent data
« Reply #600 on: July 03, 2019, 10:19:39 AM »
JAXA Global Sea Ice Extent as at 2 July 2019 :   22,678,822  km2

A 4 day run of extent losses towards the false minimum in Aug/Sep.

Global extent in 1st place, 15 k below 2017, and 1,012 k below 2018.

- extent loss on this day 42k, 29k different from the the average loss of 13 k on this day,
- extent gain from minimum to date is 6.43 million km2, 1.07 million km2 (14.3%) less than the average gain of 7.50 milllion km2 by this day,
-on average 83.1% of extent gain done and 127 days to maximum in early November.
 
But before the maximum, there is firstly a false maximum (in July). Indeed the average for the 2010's has this false max in the last week in June. Perhaps this year the false maximum has happened already?
For the next 2 and a bit months extent should fall until the false minimum (in early September),  before rising to the (usually) true maximum around the 4th of November.

The Perils of Projections
The last 10 years average remaining extent gain would give a maximum of 24.20 million km2,  0.57 million km2 more than the record low maximum in 2016 and 2nd lowest in the satellite record.

Volatility
2016
was unusual. From now on to the Arctic minimum, extent loss was not spectacular but above average. Antarctic sea ice gain to maximum was mostly below average. The result was that from now to November there was almost no increase in global sea ice compared with the average increase of 1.5 million km2.

In contrast the increase in global sea ice from now in 2006 was nearly 75%, 1.15 million km2 above the average.

A demonstration that combining two separate pieces of data makes volatility very high.
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gerontocrat

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Re: Global sea ice area and extent data
« Reply #601 on: July 07, 2019, 09:34:33 AM »
JAXA Global Sea Ice Extent as at 6 July 2019 :    22,741,402  km2

A 4 day run of extent losses towards the false minimum in Aug/Sep was followed by 2 days of high gains and finally a day of a 0.5k loss..

Global extent in 1st place, 54 k below 2017, and 1,112 k below 2018.

- extent loss on this day 1k, 8k different from the the average gain of 7 k on this day,
- extent gain from minimum to date is 6.49 million km2, 0.97 million km2 (13.0%) less than the average gain of 7.47 milllion km2 by this day,
-on average 82.7% of extent gain done and 121 days to maximum in early November.
 
But before the maximum, there is firstly a false maximum (in July). Indeed the average for the 2010's has this false max in the last week in June. Perhaps this year the false maximum has happened already?
For the next 2 and a bit months extent should fall until the false minimum (in early September),  before rising to the (usually) true maximum around the 4th of November.

The Perils of Projections
The last 10 years average remaining extent gain would give a maximum of 24.30 million km2,  0.67 million km2 more than the record low maximum in 2016 and 2nd lowest in the satellite record.

Volatility
2016
was unusual. From now on to the Arctic minimum, extent loss was not spectacular but above average. Antarctic sea ice gain to maximum was mostly below average. The result was that from now to November there was a decrease in global sea ice extent compared with the average increase of 1.5 million km2.

In contrast the increase in global sea ice from now in 2006 was nearly 70% above the average.

A demonstration that combining two separate pieces of data makes volatility very high.
"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: Global sea ice area and extent data
« Reply #602 on: July 08, 2019, 07:35:30 AM »
The graphs show what happens with high Arctic extent loss and low Antarctic extent gain.
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Tony Mcleod

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Re: Global sea ice area and extent data
« Reply #603 on: July 08, 2019, 11:23:42 AM »
"A demonstration that combining two separate pieces of data makes volatility very high."

I'm not sure it is. One of those separate pieces of data (the Arctic) is made up of a dozen or so separate pieces of data - the regions. I suspect volatility doesn't change much and if anything is reduced.

To balance out my pedantic pickiness I want to express my ongoing gratitude for your excellent analysis and reporting.  ;)

Stephan

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Re: Global sea ice area and extent data
« Reply #604 on: July 09, 2019, 06:45:21 PM »
JAXA arctic sea ice extent is now three days ahead of the 2010s average, and 12 days behind the Antarctic 2010s extent. This sums up to 15 days of more insulation, or more freezing energy that has to be released to reach the ice extent.
In comparison with the 2000s average the sum is higher (26 days), compared with the 1990s average the sum is 33 days. The highest difference results with the 1980s average (43 days).
These numbers matter, when it comes to the energy balance of our planet.

oren

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Re: Global sea ice area and extent data
« Reply #605 on: July 10, 2019, 03:14:59 AM »
JAXA arctic sea ice extent is now three days ahead of the 2010s average, and 12 days behind the Antarctic 2010s extent. This sums up to 15 days of more insulation, or more freezing energy that has to be released to reach the ice extent.
In comparison with the 2000s average the sum is higher (26 days), compared with the 1990s average the sum is 33 days. The highest difference results with the 1980s average (43 days).
These numbers matter, when it comes to the energy balance of our planet.
Returning to the problematic nature of summing two semi-related numbers, the Antarctic is currently in austral winter, hence the 12 days of insolation don't matter as much as it would seem. The 3 days are in boreal summer and matter a lot.

Stephan

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Re: Global sea ice area and extent data
« Reply #606 on: July 10, 2019, 09:07:53 PM »
I do think that also the lack of sea ice around Antarctica matters a lot. I am a layman, so please correct me if I'm wrong with my understanding.
As long as there are open waters (where used to be ice before) the temperature cannot drop too low. And when ice freezes, the freezing energy will be released into the waters below it and into the atmosphere. This also "saves" the area where it happens from becoming too cold. And in consequence the ice will be thinner than it used to be before 2015, and might be easier melted or broken up when the Austral summer starts...

oren

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Re: Global sea ice area and extent data
« Reply #607 on: July 10, 2019, 09:47:21 PM »
Of course Antarctic sea ice matters, I was just saying it is not additive in a simple way with the way Arctic sea ice matters.

gerontocrat

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Re: Global sea ice area and extent data
« Reply #608 on: July 14, 2019, 11:25:17 AM »
JAXA Global Sea Ice Extent as at 13 July 2019 :  22,726,409 km2

We are now in the period of extent losses towards the false minimum of late August / Early September

The overall picture for July sea ice so far is
- Antarctic sea ice gain more above than below average,
- Arctic sea ice loss more above than below average,
- Global extent more or less unchanged since 1 July.

Global extent in 1st place, 62 k below 2017, and 1,048 k below 2018.

- extent gain on this day 9k, 45k different from the the average loss of 36 k on this day,
- extent gain from minimum to date is 6.48 million km2, 0.87 million km2 (11.8%) less than the average gain of 7.34 milllion km2 by this day,
-on average 81.4% of extent gain done and 114 days to maximum in early November.
 
We should have passed the false maximum of early July.
For the next 2 months or a bit less extent should fall until the false minimum (in early September),  before rising to the (usually) true maximum around the 4th of November.

The Perils of Projections
The last 10 years average remaining extent gain would give a maximum of 24.40 million km2,  0.76 million km2 more than the record low maximum in 2016 and 2nd lowest in the satellite record.
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: Global sea ice area and extent data
« Reply #609 on: July 16, 2019, 06:13:09 AM »
Low Arctic extent loss and high Antarctic extent gains.
"Para a Causa do Povo a Luta Continua!"
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Stephan

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Re: Global sea ice area and extent data
« Reply #610 on: July 16, 2019, 06:43:05 PM »
On July 14 for the first time since March 28 the difference of global SIE to the 2000s average is below 2 M km²

gerontocrat

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Re: Global sea ice area and extent data
« Reply #611 on: July 20, 2019, 10:57:05 AM »
JAXA Global Sea Ice Extent as at 19 July 2019 :  22,726,409 km2

We are now in the period of extent losses towards the false minimum of late August / Early September

The overall picture for July sea ice so far is
- Antarctic sea ice gain more above than below average,
- Arctic sea ice loss more above than below average,

And then in the last four days a switch from High Antarctic gains and low Arctic losses to an Antarctic loss and high Arctic losses. In 4 days daily change switched from a gain of 113,000 km2 to a loss of 166,000 km2.  A good demo of volatility that makes prediction of global sea ice even more of a mug's game.

Global extent in 2nd place, 70 k above 2017, and 855 k below 2018.

- extent loss on this day 166 k, 153k different from the the average loss of 13 k on this day,
- extent gain from minimum to date is 6.50 million km2, 0.64 million km2 (8.9%) less than the average gain of 7.13 milllion km2 by this day,
-on average 79.1% of extent gain done and 114 days to maximum in early November.
 
We should have passed the false maximum of early July, but....
For the next 2 months or a bit less extent should fall until the false minimum (in early September),  before rising to the (usually) true maximum around the 4th of November.

The Perils of Projections
The last 10 years average remaining extent gain would give a maximum of 24.63 million km2,  0.99 million km2 more than the record low maximum in 2016 and 2nd 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
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Stephan

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Re: Global sea ice area and extent data
« Reply #612 on: July 20, 2019, 10:27:28 PM »
Thanks for the graphs and the analysis.
What comes into my mind when I see the graph of daily changes - many of the days the change is way above or way below the average. From a statistics point of view - and we look at two sets of almost independent data (Arctic and Antarctic) - one would guess that gains on the one side make up with losses on the other side (or vice versa) and the daily change should much more follow the green (average) line than the bumpy up and down line (of 2017 or 2019).
Any ideas why this is so?

gerontocrat

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Re: Global sea ice area and extent data
« Reply #613 on: July 21, 2019, 11:56:02 AM »
JAXA Global Sea Ice Extent as at 20 July 2019 :   22,604,544 km2

We are now in the period of extent losses towards the false minimum of late August / Early September


In the last four days a switch from High Antarctic gains and low Arctic losses to an Antarctic loss and high Arctic losses. In 4 days data switched from a daily gain of 113,000 km2 to a loss of over 300,000 km2 in 2 days.  A good demo of volatility that makes prediction of global sea ice even more of a mug's game.

Global extent in 1st place, 169 k below 2017, and 929 k below 2018.

- extent loss on this day 142 k, 127k different from the the average loss of 15 k on this day,
- extent gain from minimum to date is 6.36 million km2, 0.76 million km2 (10.7%) less than the average gain of 7.12 milllion km2 by this day,
-on average 78.9% of extent gain done and 107 days to maximum in early November.
 
We should have passed the false maximum of early July, and maybe this time we have...
For a bit less than 2 months more extent should fall until the false minimum (in early September),  before rising to the (usually) true maximum around the 4th of November.

The Perils of Projections
The last 10 years average remaining extent gain would give a maximum of 24.51 million km2,  0.87 million km2 more than the record low maximum in 2016 and 2nd lowest in the satellite record.
_____________________________________________________________
ps: quote from stephan
Quote
From a statistics point of view - and we look at two sets of almost independent data (Arctic and Antarctic) - one would guess that gains on the one side make up with losses on the other side (or vice versa) and the daily change should much more follow the green (average) line than the bumpy up and down line (of 2017 or 2019).
Any ideas why this is so?
If it was truly random it would be like 2 people independently tossing a coin. Each time, 4 possibilities.
Heads +1, Tails -1.

HH = +1 +1 = 2
TT  = -1 -1 = -2
TH  = -1 +1 = 0
HT  = +1 -1 = 0
Does that mean that half the time variations from the average should cancel each other out?
Does that mean the graph suggests there is a connection between short-term changes in Arctic extent losses and Antarctic extent gains?

Or does it just mean I have muddied the waters even more?
« Last Edit: July 21, 2019, 12:37:14 PM by gerontocrat »
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psymmo7

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Re: Global sea ice area and extent data
« Reply #614 on: July 21, 2019, 12:25:34 PM »
Hi Gerontocrat,
sorry to report that the table in your last post appears to have been from the day before. Graphs & Comments were update.
The prediction business may be a mug's game. More important to note, I think, is the number of days this year that global sea ice extent has been at a record low and, thanks to your posts, we know. Very many thanks once again for your great service to the ASIF forum.

oren

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Re: Global sea ice area and extent data
« Reply #615 on: July 21, 2019, 12:28:33 PM »
Re the superposition of Arctic and Antarctic, in reality the Antarctic has both a higher mean daily magnitude and a higher volatility around the mean.  So it's the Antarctic that mostly sets the tone.

gerontocrat

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Re: Global sea ice area and extent data
« Reply #616 on: July 21, 2019, 12:38:36 PM »
Hi Gerontocrat,
sorry to report that the table in your last post appears to have been from the day before.
Whoops. Corrected
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Stephan

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Re: Global sea ice area and extent data
« Reply #617 on: July 21, 2019, 02:10:32 PM »

ps: quote from stephan
Quote
From a statistics point of view - and we look at two sets of almost independent data (Arctic and Antarctic) - one would guess that gains on the one side make up with losses on the other side (or vice versa) and the daily change should much more follow the green (average) line than the bumpy up and down line (of 2017 or 2019).
Any ideas why this is so?
If it was truly random it would be like 2 people independently tossing a coin. Each time, 4 possibilities.
Heads +1, Tails -1.

HH = +1 +1 = 2
TT  = -1 -1 = -2
TH  = -1 +1 = 0
HT  = +1 -1 = 0
Does that mean that half the time variations from the average should cancel each other out?
Does that mean the graph suggests there is a connection between short-term changes in Arctic extent losses and Antarctic extent gains?

Or does it just mean I have muddied the waters even more?
Thank you gerontocrat for having opened my eyes.
Your example is of course far too simple (giving only -2, 0 and +2 as results), but it explains the behaviour quite well.
On both sides the daily changes show deviations from the average, some consecutive days the losses (or gains) are greater or smaller than average with a frequency of 0.2 to 0.4 days-1. And if these "wavy" changes are not perfectly synchronised with the other side (and why should they?) then greater than average changes are more likely than I had expected at first thought.
« Last Edit: July 21, 2019, 04:09:08 PM by Stephan »

gerontocrat

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Re: Global sea ice area and extent data
« Reply #618 on: July 22, 2019, 08:26:50 AM »
JAXA Global Sea Ice Extent as at 21 July 2019 :    22,517,642

We are now in the period of extent losses towards the false minimum of late August / Early September


A day of high Arctic extent loss and low Antarctic gain.
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gerontocrat

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Re: Global sea ice area and extent data
« Reply #619 on: July 26, 2019, 11:51:49 AM »
Definitely quite a couple of weeks for demonstrating the high volatility inherent in Global Sea ice data.

But will the 365 day trailing average continuing falling, plumbing new lows by Spring 2020?
Or will the apparent good fit trend line turn out to be an illusion (as is so often the case)?
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gerontocrat

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Re: Global sea ice area and extent data
« Reply #620 on: July 27, 2019, 02:09:04 PM »
JAXA Global Sea Ice Extent as at 26 July 2019 :  22,449,659  km2

We are now in the period of extent losses towards the false minimum of late August / Early September

In the last week mainly below average Antarctic gain and higher than average Arctic losses.

Global extent in 1st place for the 93rd day this year.
Extent 536 k below 2017, and 767 k below 2018, and 1,005 k below the record low and extraordinary** year of 2016.

- extent loss on this day 60 k, 89k different from the the average gain of 29 k on this day,
- extent gain from minimum to date is 6.20 million km2, 0.87 million km2 (12.3%) less than the average gain of 7.07 milllion km2 by this day,
-on average 78.4% of extent gain done and 101 days to maximum in early November.
 
We should have passed the false maximum of early July, and maybe this time we have...
For a bit less than 2 months more extent should fall on most days until the false minimum (in early September),  before rising to the (usually) true maximum around the 4th of November.

The Perils of Projections
The last 10 years average remaining extent gain would give a maximum of 24.40 million km2,  0.76 million km2 more than the record low maximum in 2016 of 23.64 million km2, and 2nd lowest in the satellite record.
_____________________________________________________________
**Yes, 2016 went from 1 million above 2019 as of 26 July to a 2012 style record low in November that still looks like being 0.75 million below 2019 at that time. I remember looking at the data in disbelief day after day.
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DrTskoul

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Re: Global sea ice area and extent data
« Reply #621 on: July 27, 2019, 02:37:50 PM »
Do we have a new minimum for the secondary peak of the year ?

philopek

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Re: Global sea ice area and extent data
« Reply #622 on: July 27, 2019, 02:57:14 PM »
Do we have a new minimum for the secondary peak of the year ?

Looks a lot like it, yes, I'd say so.

gerontocrat

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Re: Global sea ice area and extent data
« Reply #623 on: July 31, 2019, 09:27:21 AM »
What goes down, must go down even more?
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Stephan

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Re: Global sea ice area and extent data
« Reply #624 on: July 31, 2019, 09:39:23 PM »
Do we have a new minimum for the secondary peak of the year ?

Looks a lot like it, yes, I'd say so.
From JAXA the following years have the lowest false maximum in July:
2019 22.99 M km²
2017 23.05 M km²
2011 23.56 M km²
2016 23.76 M km²
2018 23.94 M km²
2012 24.05 M km²
2006 24.36 M km²

So 2019 set a new record...

gerontocrat

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Re: Global sea ice area and extent data
« Reply #625 on: August 01, 2019, 09:09:46 AM »
JAXA Global Sea Ice Extent as at 31 July 2019 :   22,371,689  km2

We are now in the period of extent losses towards the false minimum of late August / Early September

In the last week overall global sea ice extent went down in line with average.

Global extent in 1st place for 98 days this year.
Extent 524 k below 2017, and 754 k below 2018, and 926 k below the record low and extraordinary** year of 2016.

- extent loss on this day 15 k, 11k different from the the average loss of 4 k on this day,
- extent gain from minimum to date is 6.12 million km2, 0.90 million km2 (12.8%) less than the average gain of 7.02 milllion km2 by this day,
-on average 77.8% of extent gain done and 96 days to maximum in early November.
 
- We have passed the false maximum of early July, 
- For a bit less than 2 months more extent should fall on most days until the false minimum (in early September),  before rising to the (usually) true maximum around the 4th of November.

The Perils of Projections
The last 10 years average remaining extent gain would give a maximum of 24.38 million km2,  0.74 million km2 more than the record low maximum in 2016 of 23.64 million km2, and 2nd lowest in the satellite record.
_____________________________________________________________
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: Global sea ice area and extent data
« Reply #626 on: August 05, 2019, 04:00:54 PM »
JAXA Global Sea Ice Extent as at 4 August 2019 :  22,393,431  km2

We are now in the period of extent losses towards the false minimum of late August / Early September

In the last few days overall global sea ice extent has barely changed.

Global extent in 2nd place after 101 days this year at lowest. But probably for one day only.

Extent 31 k above 2017, and 660 k below 2018, and 599 k below the record low and extraordinary** year of 2016.

- extent loss on this day 17 k, 11k different from the the average loss of 6 k on this day,
- extent gain from minimum to date is 6.14 million km2, 0.81 million km2 (11.6%) less than the average gain of 6.95 milllion km2 by this day,
-on average 77.0% of extent gain done and 92 days to maximum in early November.
 
- We have passed the false maximum of early July, 
- For a bit less than 2 months more extent should fall on most days until the false minimum (in early September),  before rising to the (usually) true maximum around the 4th of November.

The Perils of Projections
The last 10 years average remaining extent gain would give a maximum of 24.47 million km2,  0.83 million km2 more than the record low maximum in 2016 of 23.64 million km2, and 2nd lowest in the satellite record.
_____________________________________________________________
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: Global sea ice area and extent data
« Reply #627 on: August 06, 2019, 08:35:02 AM »
As expected, 2019 lowest again - but by more  than expected (high Arctic loss, low Antarctic gain).
And here are the graphs to prove it.
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petm

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Re: Global sea ice area and extent data
« Reply #628 on: August 07, 2019, 01:26:13 AM »
Stumbled on this excellent graphic. I'm sure it doesn't belong in this thread though. If someone knows a better place for it, please reply and I'll move it.

Sea ice 1992-2018 ASI-SSMI - by DKRZ
https://www.youtube.com/watch?v=Z17j6Nfhfvs&feature=youtu.be

philopek

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Re: Global sea ice area and extent data
« Reply #629 on: August 07, 2019, 02:05:34 AM »
Stumbled on this excellent graphic. I'm sure it doesn't belong in this thread though. If someone knows a better place for it, please reply and I'll move it.

Sea ice 1992-2018 ASI-SSMI - by DKRZ
https://www.youtube.com/watch?v=Z17j6Nfhfvs&feature=youtu.be

Yes, outstanding find, thank you  8)

gerontocrat

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Re: Global sea ice area and extent data
« Reply #630 on: August 11, 2019, 10:25:49 AM »
JAXA Global Sea Ice Extent as at 10 August 2019 :   22,208,734  km2

We are now in the period of extent losses towards the false minimum of late August / Early September

Until this day, in the last two weeks overall global sea ice extent barely changed, instead of gradually reducing. But on this day, a very high Arctic extent loss and a modest Antarctic extent loss (as opposed to a modest increase) meant that Global extent crashed down.

Global extent in 1st place, 105 days this year at lowest.

Extent 146 k below 2017, 472 k below 2018, and 861 k below the record low and extraordinary** year of 2016.

- extent loss on this day 144 k, 117 k different from the the average loss of 27 k on this day,
- extent gain from minimum to date is 5.96 million km2, 0.85 million km2 (12.5%) less than the average gain of 6.81 milllion km2 by this day,
-on average 75.5% of extent gain done and 86 days to maximum in early November.
- For a bit less than 1 month more extent should fall on most days until the false minimum (in early September),  before rising to the (usually) true maximum around the 4th of November.

The Perils of Projections
The last 10 years average remaining extent gain would give a maximum of 24.42 million km2, 0.78 million km2 more than the record low maximum in 2016 of 23.64 million km2, and 2nd 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)

gerontocrat

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Re: Global sea ice area and extent data
« Reply #631 on: August 14, 2019, 02:21:48 PM »
The July JAXA global sea ice extent false maximum in July was a record low.

Mainly due to high Arctic extent losses we may well be heading for a record low false August/September minimum fairly soon.
"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: Global sea ice area and extent data
« Reply #632 on: August 14, 2019, 07:09:09 PM »
It looks like that... what a trend

gerontocrat

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Re: Global sea ice area and extent data
« Reply #633 on: August 18, 2019, 09:08:01 AM »
JAXA Global Sea Ice Extent as at 17 August 2019 :    22,029,442  km2

We are now in the period of extent losses towards the false minimum of late August / Early September. So this analysis concentrates on that

In the last week overall mostly high Arctic extent losses and modest Antarctic extent gains has meant that Global Sea Ice Extent has reduced ahead of trend.

Global extent in 1st place, 112 days this year at lowest.

Extent 200 k below 2017, 569 k below 2018, and 1,078 k below the record low year of 2016.

- extent loss on this day 24 k, 7 k different from the the average loss of 18 k on this day,
- extent gain from minimum to date is 5.78 million km2, 0.86 million km2 (12.9%) less than the average gain of 6.64 milllion km2 by this day,
-on average 73.6% of extent gain done and 79 days to maximum in early November.

- For just under 3 weeks sea ice extent should fall on most days until the false minimum (in early September),  before rising to the (usually) true maximum around the 4th of November.

The Perils of Projections - to the False Minimum

And every day a surprise. The record false minimum was in 2012, at the very early date of 26 August. After that date extent rose very rapidly. So I have temporarily added 2012 to Graph AA4.

- There are on average 19 more days of extent losses to the false minimum on 4th September,
- The last 10 years average remaining extent loss would give a minimum of 21.49 million km2, 0.42 million km2 less than the record low false minimum in 2012 of 21.91 million km2, and  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)

gerontocrat

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Re: Global sea ice area and extent data
« Reply #634 on: Today at 01:21:46 PM »
JAXA Global Sea Ice Extent as at 23 August 2019 :  22,038,468 km2

We are now in the period of extent losses towards the false minimum of late August / Early September. So this analysis concentrates on that

In the last week overall mostly low Arctic extent losses and somewhat above Antarctic extent gains has meant that Global Sea Ice Extent has not reduced.

Global extent in 1st place, 118 days this year at lowest.

Extent 464 k below 2017, 503 k below 2018, and 939 k below the record low year of 2016, but only 12k below 2012. Unless Global Sea Ice Extent drops sharply, for the next week to 10 days 2012 will be lowest in the satellite record.

- extent gain from the March minimum to date is 5.79 million km2, 0.74 million km2 (11.4%) less than the average gain of 6.53 milllion km2 by this day,
-on average 72.4% of extent gain done and 73 days to the maximum in early November.

- For about 2 weeks more sea ice extent should fall on most days until the false minimum (in early September),  before rising to the (usually) true maximum around the 4th of November.

The Perils of Projections - to the False Minimum

[iThe record false minimum was in 2012, at the very early date of 26 August. After that date extent rose very rapidly. So I have temporarily added 2012 to Graph AA4.[/i]

- There are on average 12 more days of extent losses to the false minimum on 4th September,
- The last 10 years average remaining extent loss would give a minimum of 21.61 million km2, 0.30 million km2 less than the record low false minimum in 2012 of 21.91 million km2, and  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)

DrTskoul

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Re: Global sea ice area and extent data
« Reply #635 on: Today at 01:47:56 PM »
One GAC away from lowest false minimum?

gerontocrat

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Re: Global sea ice area and extent data
« Reply #636 on: Today at 02:46:36 PM »
One GAC away from lowest false minimum?
Don't need a GAC, just need sum of next few days of Arctic extent loss + Antarctic extent gain to be around the average net loss, or even a bit less overall loss than that.
"Para a Causa do Povo a Luta Continua!"
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dnem

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Re: Global sea ice area and extent data
« Reply #637 on: Today at 02:49:54 PM »
Don't need either.  The difference has to be within the measurement error and we are essentially there.

Pmt111500

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Re: Global sea ice area and extent data
« Reply #638 on: Today at 03:50:45 PM »
For a moment I thought I was looking at the Arctic thread and wondered what had happened to 2012 data. I'd like a definite minimum here and not all this 'within error bars' stuff. Couple of centuries down, please, so we can say this is a bad year for ice, lol.
Amateur observations of Sea Ice since 2003.