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Author Topic: The 2018/2019 freezing season  (Read 232918 times)

Thomas Barlow

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Re: The 2018/2019 freezing season
« Reply #1200 on: March 16, 2019, 08:50:09 PM »
And yet another way of looking at NSIDC extent max & min over the years.
Thanks Tor Bejnar and Gerontocrat.
I was trying to see if there is a correlation between a low winter and low Sept. extent, but more importantly, if years that had low winter and summer extents back-to-back in a year, if they were getting more frequent.
Probably not enough longterm data to see a trend yet.


etienne

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Re: The 2018/2019 freezing season
« Reply #1201 on: March 17, 2019, 11:12:07 AM »
I have also been wondering such things, also if melting starting more on the Chukchy or Barentsz would have an impact on the minimal extent, but I couldn't find anything clear.

I feel that extent is not a very good parameter when we are at the maximum or at the minimum because small changes in the % of ice in the sea can have a huge impact on final values. It's more the weather than the climate that is considered when values oscillate.

vox_mundi

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Klondike Kat

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Re: The 2018/2019 freezing season
« Reply #1203 on: March 26, 2019, 12:59:04 PM »
Nothing unusual about this years' maximum, except perhaps that it was a few hundred thousand square kilometers higher than the previous four years.

Archimid

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Re: The 2018/2019 freezing season
« Reply #1204 on: March 26, 2019, 03:26:14 PM »
That's right. Record level lows are now the new normal, until we hit the next threshold.
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Jim Hunt

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Re: The 2018/2019 freezing season
« Reply #1205 on: March 27, 2019, 09:05:25 AM »
Nothing unusual about this years' maximum, except perhaps that it was a few hundred thousand square kilometers higher than the previous four years.

Except perhaps a few hundred thousand square kilometers of peripheral Arctic sea ice were somewhat thinner than in the previous four years?

https://forum.arctic-sea-ice.net/index.php/topic,2591.msg193014.html#msg193014
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Klondike Kat

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Re: The 2018/2019 freezing season
« Reply #1206 on: March 27, 2019, 12:54:32 PM »
Nothing unusual about this years' maximum, except perhaps that it was a few hundred thousand square kilometers higher than the previous four years.

Except perhaps a few hundred thousand square kilometers of peripheral Arctic sea ice were somewhat thinner than in the previous four years?

https://forum.arctic-sea-ice.net/index.php/topic,2591.msg193014.html#msg193014

I suspect all new ice is thinner than older ice.  I presume you mean average thickness, but even that can be skewed by new ice.  The fact that in the previous four years, there was no ice, any ice is thicker than previously open water.

Jim Hunt

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Re: The 2018/2019 freezing season
« Reply #1207 on: March 27, 2019, 01:24:31 PM »
Any ice is thicker than previously open water.

Not for long at suitably southern latitudes however.
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

magnamentis

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Re: The 2018/2019 freezing season
« Reply #1208 on: March 27, 2019, 10:22:52 PM »
Nothing unusual about this years' maximum, except perhaps that it was a few hundred thousand square kilometers higher than the previous four years.

Except perhaps a few hundred thousand square kilometers of peripheral Arctic sea ice were somewhat thinner than in the previous four years?

https://forum.arctic-sea-ice.net/index.php/topic,2591.msg193014.html#msg193014

i think what he means is clear and true, 10 times the amount of thin ice ultimately will be gone earlier than 1x 5m thick ice.

i know we are not talking about 5m thick ice, i just used this example to point out what is meant when saying that the slightly higher extent does not mean much as compared to the slightly smaller extent but with significantly higher thickness.

at the end it's all about volume/ice-mass.  500'000km2 x 50cm is more ice to melt than 600'000km2 x 30cm for example because the mass/volume is higher and the energy needed to melt it is significantly higher.

in addition to that, higher extent means farther south, means higher and earlier insolation.

after all the current extent fall off the cliff indicates and illustrates that quite well and it will probably continue for anothe 5-10 days.

I suspect all new ice is thinner than older ice.  I presume you mean average thickness, but even that can be skewed by new ice.  The fact that in the previous four years, there was no ice, any ice is thicker than previously open water.

jdallen

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Re: The 2018/2019 freezing season
« Reply #1209 on: March 28, 2019, 01:11:53 AM »
Nothing unusual about this years' maximum, except perhaps that it was a few hundred thousand square kilometers higher than the previous four years.

Except perhaps a few hundred thousand square kilometers of peripheral Arctic sea ice were somewhat thinner than in the previous four years?

https://forum.arctic-sea-ice.net/index.php/topic,2591.msg193014.html#msg193014

i think what he means is clear and true, 10 times the amount of thin ice ultimately will be gone earlier than 1x 5m thick ice.

i know we are not talking about 5m thick ice, i just used this example to point out what is meant when saying that the slightly higher extent does not mean much as compared to the slightly smaller extent but with significantly higher thickness.

at the end it's all about volume/ice-mass.  500'000km2 x 50cm is more ice to melt than 600'000km2 x 30cm for example because the mass/volume is higher and the energy needed to melt it is significantly higher.

in addition to that, higher extent means farther south, means higher and earlier insolation.

after all the current extent fall off the cliff indicates and illustrates that quite well and it will probably continue for anothe 5-10 days.

I suspect all new ice is thinner than older ice.  I presume you mean average thickness, but even that can be skewed by new ice.  The fact that in the previous four years, there was no ice, any ice is thicker than previously open water.
Its measurable.  Its your surface to volume ratio, which governs heat exchange.  When comparing the same volume of ice, your surface increases as an inverse ratio of thickness. E.g. 1M ice will have 5 times the surface exposure as the same volume of 5M ice.

And in that, you have the primary driver of the volatility we see in extent and area.
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be cause

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Re: The 2018/2019 freezing season
« Reply #1210 on: April 28, 2019, 06:39:40 PM »
ascat and amsr2-uhh sep17-feb28.

I said at the time that based on this one post I would predict suprisingly low area and volume later this summer . The last 8 weeks and the current forecasts only increase my confidence ...
Hi Uniquorn .. I loved this format and hope you will consider republishing the whole season monthly so we can watch events unfold . As nearly 10,000 have downloaded this wee vid , I am clearly not alone in appreciating the enormity of it's value ! Cheers .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...