Arctic Sea Ice : Forum

Cryosphere => Arctic sea ice => Topic started by: Jim Hunt on April 03, 2019, 01:24:59 PM

Title: Are 3 dimensions better than 2?
Post by: Jim Hunt on April 03, 2019, 01:24:59 PM
A place to be nice whilst debating volume/thickness versus area/extent whilst not cluttering up the 2019 melting season thread:

https://forum.arctic-sea-ice.net/index.php/topic,2591.msg193705.html#msg193705

A few facts for you:

http://GreatWhiteCon.info/2019/04/facts-about-the-arctic-in-april-2019/
Title: Re: Are 3 dimensions better than 2?
Post by: Midnightsun on April 03, 2019, 01:54:40 PM
I was really pondering this while reading the other thread.

Loss of extent/area --> decreased albedo, increased potential for waves --> more melt

Loss of volume should logically lag behind since thin ice melts faster, and thick ice is more resistant to melt, but once it goes it's gone.

So imo, both are important to track but extent comes first.

(Why are climate deniers do obsessed with volume?)
Title: Re: Are 3 dimensions better than 2?
Post by: vox_mundi on April 03, 2019, 02:10:02 PM
A binary poll might illuminate the consensus.
Title: Re: Are 3 dimensions better than 2?
Post by: Jim Hunt on April 03, 2019, 02:11:48 PM
A binary poll might illuminate the consensus.

Your wish is my command!
Title: Re: Are 3 dimensions better than 2?
Post by: gerontocrat on April 03, 2019, 02:51:19 PM
Extent has fallen by nearly 1 million km2 since extent maximum on March 12th to March 31st. That is 10% of the average total season melt c.f. the average of 3%. Area decreased by 862 k.

In the same period volume increased by 209 km3 from 22,209 to 22,218 km3.

As a result thickness increased.

So, did sea ice increase or decrease in that period? Which dimensions will you choose to use to make the call?

 
Title: Re: Are 3 dimensions better than 2?
Post by: Archimid on April 03, 2019, 03:18:15 PM
Sea ice increased. The surface area that is covered in sea ice decreased.
Title: Re: Are 3 dimensions better than 2?
Post by: Jim Hunt on April 03, 2019, 03:18:44 PM
So, did sea ice increase or decrease in that period? Which dimensions will you choose to use to make the call?

It increased in the centre, and decreased around the periphery.

Volume! In the centre area and extent are pretty much constant at this time of year.
Title: Re: Are 3 dimensions better than 2?
Post by: Juan C. García on April 03, 2019, 03:24:26 PM
3 dimensions are real, 2 dimensions is just a concept, an idea, an abstract of reality.
Title: Re: Are 3 dimensions better than 2?
Post by: b_lumenkraft on April 03, 2019, 03:29:42 PM
So, did sea ice increase or decrease in that period? Which dimensions will you choose to use to make the call?

Depends on what the story is you are telling. i.e.:

If you talk buffer effects of the Arctic sea ice, you'll take volume as a measure.
If you talk albedo, you'll take extend as a measure.
Title: Re: Are 3 dimensions better than 2?
Post by: b_lumenkraft on April 03, 2019, 03:30:06 PM
3 dimensions are real, 2 dimensions is just a concept, an idea, an abstract of reality.

Word!  :D
Title: Re: Are 3 dimensions better than 2?
Post by: LRC1962 on April 03, 2019, 03:54:13 PM
So, did sea ice increase or decrease in that period? Which dimensions will you choose to use to make the call?

Depends on what the story is you are telling. i.e.:

If you talk buffer effects of the Arctic sea ice, you'll take volume as a measure.
If you talk albedo, you'll take extend as a measure.
Then you can add a 3rd component and that is mass of 3D ice. As seen in both 2007 and '12 both large melt offs, but for different weather reasons, happened primarily because large volume was hiding little mass.
Title: Re: Are 3 dimensions better than 2?
Post by: Jim Hunt on April 03, 2019, 04:09:08 PM
If you talk buffer effects of the Arctic sea ice, you'll take volume as a measure.
If you talk albedo, you'll take extend as a measure.

Whilst I agree in general terms, by request there is now a binary poll at the top.

You can't sit on the fence, if you want your vote to count at least!

Also I'd quibble slightly and say "If you want to talk albedo, you'll take area and melt ponds into account."
Title: Re: Are 3 dimensions better than 2?
Post by: b_lumenkraft on April 03, 2019, 04:20:29 PM
melt ponds

2D or 3D melt ponds?? :P

Yes, i was about to correct 'extend' to 'area', but forgot.  :-[
Title: Re: Are 3 dimensions better than 2?
Post by: Juan C. García on April 03, 2019, 04:42:13 PM
If you want to calculate the heat absorbed with the albedo, you use 2 dimensions, but if you want to go further and analyse the heat transfer, you have to go 3D.
And with the time series (how is changing day by day) then you are on the 4D.  ;)
Title: Re: Are 3 dimensions better than 2?
Post by: gerontocrat on April 03, 2019, 04:48:39 PM
As I, with reluctance and sadness, have just resigned from "The Flat Earth Society", I have no choice but to vote for 3 dimensions.

What about the 4th dimension, or even a few more in parallel universes?
Title: Re: Are 3 dimensions better than 2?
Post by: vox_mundi on April 03, 2019, 05:09:29 PM
As I, with reluctance and sadness, have just resigned from "The Flat Earth Society", I have no choice but to vote for 3 dimensions.

What about the 4th dimension, or even a few more in parallel universes?

4th dimension and alternate realities are covered here:

https://forum.arctic-sea-ice.net/index.php/topic,1578.msg192698.html#msg192698
Title: Re: Are 3 dimensions better than 2?
Post by: Pmt111500 on April 03, 2019, 05:30:07 PM
I occupy a slice in 2d multiverse so it's obvious time is the 3rd dimension.

(Modified: oops this was about ice. Change the first words to "ice occupies" and add "on the positively curved 2d surface" at the proper place.
Title: Re: Are 3 dimensions better than 2?
Post by: b_lumenkraft on April 04, 2019, 09:50:51 AM
Paladiea, can you or someone briefly elaborate on how density would influence melting, please.

(Repeating myself)^n

https://forum.arctic-sea-ice.net/index.php/topic,2618.0.html

Sorry Jim, it wasn't my intent to overslaugh your great thread.

So, feel free to elaborate in length on the 2Dness of slushed vs. dense ice. :P
Title: Re: Are 3 dimensions better than 2?
Post by: epiphyte on April 04, 2019, 10:26:23 AM
All three are needed to derive meaning, and also time. Without all of the dimensions, one sees only a shadow. 

An imperfect analogy, but think of it as a live musical performance - a summation of amplitudes and frequencies, projected onto a surface. Without all of the parameters,  you can't tell Mozart from Metallica.
Title: Re: Are 3 dimensions better than 2?
Post by: Dharma Rupa on April 04, 2019, 01:17:38 PM
In my own private corner of the Metaverse the spheres start as small circles when you first see them and then grow into large circles which are clearly projections of spheres as you get close enough to really see them.  So I think you have to have at least 4 spatial dimensions.

About ice???  Well, it seems to me our problem is that to properly represent Arctic Ice you need 12 or so dimensions in an Information Space.

(I reluctantly voted for 3, lacking higher available choices.)
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 04, 2019, 01:37:34 PM
Not even including the much greater uncertainty when adding the third dimension (thickness), I voted for two dimensions.  This should come as no surprise to those who have followed my posts.  Allow me to elaborate.  The albedo effect is based on two dimensions; adding thickness will only change the albedo marginally when the ice is extremely thin, while the difference between any ice and open water is huge.  Weather is unaffected by ice thickness also.  The entire evapotranspiration process is cutoff, when the water is covered by ice.  This effectively changes the Arctic from an ocean system to a desert.  Extent has a much greater effect on wildlife than thickness.  The ice forms an effective barrier between the air and water, and the size of the barrier is largely immaterial.  Animals above cannot feed on those below, and mammals below cannot surface. 

Given the topic at hand, the differences between open water and an ice-covered surface is significantly greater than the difference in ice thickness.
Title: Re: Are 3 dimensions better than 2?
Post by: gerontocrat on April 04, 2019, 05:53:00 PM
Here are some example graphs on ice area and volume.

Bering Sea.  The data is consistent in that both volume and area are falling quickly and both are well below the 2010's average.

Barents Sea. The data is not consistent. In the last week of March volume loss stalls and rises a bit while area keeps on going down. Volume remains well above the 201's average while area is now well below.
Title: Re: Are 3 dimensions better than 2?
Post by: LRC1962 on April 04, 2019, 10:06:37 PM
Weather is unaffected by ice thickness also.  The entire evapotranspiration process is cutoff, when the water is covered by ice. 

Given the topic at hand, the differences between open water and an ice-covered surface is significantly greater than the difference in ice thickness.

GAC2012, in case one has forgotten, puts a great lie to those statements. The GAC ran onto ice, which if thick and solid would have died out quickly as the temp differential between the outer edge and core would have become the same as both would have been using the same air. What happened in 2012, the ice was thin or if thick very broken, which when the storm first hit dispersed the ice giving access to open water. End result was the temp differential remained high enough the the storm continued doing damage for a very long time. Volume and density do matter very much.
Another factor is waves. Waves hitting a wall of dense thick ice lose all their energy very fast. In 2007, scientists witnessed many times where waves were entering ice fields 100's of miles from the edge and destroying ice over 10 meters thick because the ice was really nothing more then slush. Again volume and density matter.
The last few years we have not seen a GAC nor the kind of wave action that destroys fragile ice and therefore extent has been a very important factor as  far as the shape of ice appears to be in, but if we get another storm like in 2012 or wave action like in 2007, and I feel that we would witness very large fast decline in the ice, because the volume and density of the ice that is around is very very fragile.
BTW I have not voted because it all depends on the weather. Some conditions the 2D metric is far better, but in others the 3D is far better. If we ever can get to the point of getting reliable density measurements, that would be even better.
Title: Re: Are 3 dimensions better than 2?
Post by: Archimid on April 04, 2019, 11:44:58 PM
This should come as no surprise to those who have followed my posts.

I have followed your posts. You seem to have most things backwards.

Quote
The albedo effect is based on two dimensions;

Not true for sea ice, but likely true for ocean water. 

From  NSIDC

Quote
Sea ice has a much higher albedo compared to other earth surfaces, such as the surrounding ocean. A typical ocean albedo is approximately 0.06, while bare sea ice varies from approximately 0.5 to 0.7. This means that the ocean reflects only 6 percent of the incoming solar radiation and absorbs the rest, while sea ice reflects 50 to 70 percent of the incoming energy. The sea ice absorbs less solar energy and keeps the surface cooler.

...

Snow has an even higher albedo than sea ice, and so thick sea ice covered with snow reflects as much as 90 percent of the incoming solar radiation. This serves to insulate the sea ice, maintaining cold temperatures and delaying ice melt in the summer. After the snow does begin to melt, and because shallow melt ponds have an albedo of approximately 0.2 to 0.4, the surface albedo drops to about 0.75. As melt ponds grow and deepen, the surface albedo can drop to 0.15



Albedo can vary wildly depending on the characteristics of the ice. Thick, snow covered ice, extremely high albedo. Thin, melt pond areas have almost the Albedo of open ocean. Both snow and melt ponds are extremely relevant to volume.

Quote
adding thickness will only change the albedo marginally when the ice is extremely thin, while the difference between any ice and open water is huge. 

Again thick snow covered ice, .9 Albedo. Thin, melt ponded ice, .2-.4 Albedo. Huge difference.


Quote
Weather is unaffected by ice thickness also.
 

Maybe. The big differences (humidity, albedo, temperature) between Melt Ponds and snow might have a slight effect on weather, but the conduction difference between 2 meter ice and 5 meter ice may be negligible. However, the difference between .5 meter ice and 5 meter ice is significant



Quote
This effectively changes the Arctic from an ocean system to a desert.  Extent has a much greater effect on wildlife than thickness.

Hard to argue with that.

Quote
The ice forms an effective barrier between the air and water, and the size of the barrier is largely immaterial. 

The thickness of the barrier determines the transfer of heat between the ocean and the atmosphere. It the ocean temperatures and surface air temperature are the same, the thinner ice will melt faster and will grow faster, depending on the temperatures.


Quote
Animals above cannot feed on those below, and mammals below cannot surface.

Sure. I'm sure you are generalizing but it seems like a good assumption. 

Quote
Given the topic at hand, the differences between open water and an ice-covered surface is significantly greater than the difference in ice thickness.

If the topic is the melting season, then extent, volume and thickness are about equally important. Each as a simple scalar tells us vital information about a generalized view of the arctic, but nothing specific nor sufficient for most informed analysis. All three together gives us the best picture.

Interestingly, when extent or area are presented as a point on an arctic map, volume and thickness are completely lost. However, when presenting volume/thickness in the same manner we get area for free.
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 05, 2019, 12:55:33 AM
Sounds like you just supported my statement about albedo, even though you claim you did not.  The range given for sea ice (0.5-0.7) is much smaller than the difference between 0.6 and 0.06.  Do you really think that a 90% drop in thickness can even compare to a 90% drop in extent (or area)?  You seem to be trying awfully hard to refute my statements, when in reality, all you did was provide supporting evidence for my claims.
Title: Re: Are 3 dimensions better than 2?
Post by: jdallen on April 05, 2019, 02:36:09 AM
Sounds like you just supported my statement about albedo, even though you claim you did not.  The range given for sea ice (0.5-0.7) is much smaller than the difference between 0.6 and 0.06.  Do you really think that a 90% drop in thickness can even compare to a 90% drop in extent (or area)?  You seem to be trying awfully hard to refute my statements, when in reality, all you did was provide supporting evidence for my claims.
OK, this sounds like a setup for a straw man argument.

The fundamental problem is the two metrics *are* linked in ways which would categorically prevent a 90% drop in one without a major reduction in the other.  The relationship is dynamic and can't really be isolated in the way you want.

Your first problem is, the volume of ice in the Arctic is not uniformly distributed.   We will likely see major drops in extent at the end of season - probably not on the scale you suggest of 90% but on the order of 20 to 30% - which will outstrip the related drops in volume.  However that remaining ice will become increasingly important in buffering other changes taking place both in the ecosystem and climatalogically.

The thickness - volume - of that ice is key to its survival.  The durability of that ice increases with age.  If I recall correctly, in 2012, the average melt was on the order of 1.85M.  That's a really important number, as it pretty much identifies at the end of the refreeze what ice is going to survive the melt season or not.  Not extent.  Not area.  It reflects the seasonal uptake in heat, which in more recent years, IIRC has actually dropped back a bit to 1.7-1.8M... which is itself reflected in the recoveries in volume which took place.  (I'll have to check, but 2016 might be an outlier)

I agree, in terms of increasing the potential uptake in heat, reducing extent is a key factor, but you really cannot dismiss volume.  The system is not two dimensional.
Title: Re: Are 3 dimensions better than 2?
Post by: Archimid on April 05, 2019, 04:15:51 AM
Do you really think that a 90% drop in thickness can even compare to a 90% drop in extent (or area)?

Do you really think you should ignore a 90% thickness reduction (whatever that means)?
Title: Re: Are 3 dimensions better than 2?
Post by: Michael Hauber on April 05, 2019, 05:56:51 AM
There are two parts to the Arctic.  One part where there is too much heat during the year for ice to survive the melting season, and another part where there is not enough heat during the year to melt the ice.  Extent is the best measure of the shrinking of the zone in which ice can survive, and best measure of the long term trend in reducing the ice, and best predictor of when we will go ice free.  Those who were extrapolating volume/thickness loss around 10 years ago were predicting ice free by about now.  Those who were extrapolating extent predicted that we wouldn't be.  Looks to me like the predictions based on extent were better.

Thickness remembers recent conditions, and encodes information on how warm that part of the Arctic is.  If thickness is very low, that suggests recent temperatures have been warmer, and it is more likely that the ice won't last this specific season.  Thickness is the most important measure for predicting short term changes in ice extent and whether ice will survive the coming melt season.
Title: Re: Are 3 dimensions better than 2?
Post by: oren on April 05, 2019, 07:34:07 AM
Thickness is the most important measure for predicting short term changes in ice extent and whether ice will survive the coming melt season.
Indeed, thickness predicts short term drops in extent. You can have high temps but if all the ice is 50cm and up, it will take a while for extent to shrink. If lots of ice is very thin, you can get large drops in extent. The 2012 GAC achieved its notorious extent drops by hitting large swaths of thin vulnerable ice.
Thin ice also compacts easier than thick ice, another contribution to potential extent drops. I think this year's recent sharp drops are a combination of thin ice melting in the periphery, and not so thick ice compacting in the inner seas. Plus I assume some wind-driven wave action.
OTOH, a thick ice pack will resist melting and delay extent drops. Some years have seen long stalls at the height of the melting season, due to the ice edge being composed of thick ice (such as the string of thick old ice in the Beaufort/Chukchi in 2018 IIRC).

Ignoring the distribution of thickness (per latitude/location) is like driving blind - expect nasty surprises.
Title: Re: Are 3 dimensions better than 2?
Post by: Archimid on April 05, 2019, 12:56:40 PM
There are two parts to the Arctic.  One part where there is too much heat during the year for ice to survive the melting season, and another part where there is not enough heat during the year to melt the ice. 

True.

Quote
Extent is the best measure of the shrinking of the zone in which ice can survive,

Sorry but no. Extent is binary. Is there ice or is there no ice. That's it. It contains no information on the survival of ice without encoding geographic or temperature data. If you do the same thing to volume and thickness they will show  all the data extent does and then some.

Quote
and best measure of the long term trend in reducing the ice, and best predictor of when we will go ice free.  Those who were extrapolating volume/thickness loss around 10 years ago were predicting ice free by about now.  Those who were extrapolating extent predicted that we wouldn't be.  Looks to me like the predictions based on extent were better.

BIG TIME NO! At the same time people were extrapolating no ice by now with volume, other people were extrapolating no ice by 2070 and beyond based mostly on extent. Most of them now admit they were wrong and the estimates have been changed to earlier dates.

If we get a time machine and go to the year if the first BOE, then we can determine who was "more right" or "more wrong".

Quote
Thickness remembers recent conditions, and encodes information on how warm that part of the Arctic is.  If thickness is very low, that suggests recent temperatures have been warmer, and it is more likely that the ice won't last this specific season.  Thickness is the most important measure for predicting short term changes in ice extent and whether ice will survive the coming melt season.

Thickness is indeed a very important. Just like volume and extent. Those diminishing the importance of the higher dimensions of the arctic are wrong.
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 05, 2019, 02:06:32 PM
There are two parts to the Arctic.  One part where there is too much heat during the year for ice to survive the melting season, and another part where there is not enough heat during the year to melt the ice.  Extent is the best measure of the shrinking of the zone in which ice can survive, and best measure of the long term trend in reducing the ice, and best predictor of when we will go ice free.  Those who were extrapolating volume/thickness loss around 10 years ago were predicting ice free by about now.  Those who were extrapolating extent predicted that we wouldn't be.  Looks to me like the predictions based on extent were better.

Thickness remembers recent conditions, and encodes information on how warm that part of the Arctic is.  If thickness is very low, that suggests recent temperatures have been warmer, and it is more likely that the ice won't last this specific season.  Thickness is the most important measure for predicting short term changes in ice extent and whether ice will survive the coming melt season.

So true.  Most people do not realize that volumetric losses will always exceed areal losses, due to the added dimension (unless one dimension is held constant).  Hence, a 50% loss in surface area, equates to a 66% loss in volume (and a 30% loss in either dimension constituting the area).  This is simple mathematics (and physics).  Many erroneously claimed that area must accelerate to "catch up" to volumetric losses, when in realty, the difference between the two indicate similarity and confirmation that the system is behaving as expected.  This is evident by the decrease in volumetric losses recently, as volume slows to match areal losses. 

Using a straight linear regression of the NSDIC leads to an ice-free (less than 1 million km2) minimum in 2060.  Various scientific estimates have different, depending on which years are using in this calculation, or which curve best fits the data.  Even this may be too early, as recent minima have not followed the declining trend of the previous decade. 

I agree that this year's early losses are the recent of melting thin ice.  The maximum this year was significantly higher than the past four, and much of that ice was likely thin, first-year ice.  This made for rather easy melting, when temperatures rose.  The melt will likely decline quickly, as this thin ice has mostly melted.  Summer melt will then be on the low side, as the thickness ice will be more resistant.  Due to this prevalence of thick ice, I suspect the minimum this year will be slightly high than last.
Title: Re: Are 3 dimensions better than 2?
Post by: magnamentis on April 05, 2019, 03:17:34 PM
There are two parts to the Arctic.  One part where there is too much heat during the year for ice to survive the melting season, and another part where there is not enough heat during the year to melt the ice.  Extent is the best measure of the shrinking of the zone in which ice can survive, and best measure of the long term trend in reducing the ice, and best predictor of when we will go ice free.  Those who were extrapolating volume/thickness loss around 10 years ago were predicting ice free by about now.  Those who were extrapolating extent predicted that we wouldn't be.  Looks to me like the predictions based on extent were better.

Thickness remembers recent conditions, and encodes information on how warm that part of the Arctic is.  If thickness is very low, that suggests recent temperatures have been warmer, and it is more likely that the ice won't last this specific season.  Thickness is the most important measure for predicting short term changes in ice extent and whether ice will survive the coming melt season.

So true.  Most people do not realize that volumetric losses will always exceed areal losses, due to the added dimension (unless one dimension is held constant).  Hence, a 50% loss in surface area, equates to a 66% loss in volume (and a 30% loss in either dimension constituting the area).  This is simple mathematics (and physics).  Many erroneously claimed that area must accelerate to "catch up" to volumetric losses, when in realty, the difference between the two indicate similarity and confirmation that the system is behaving as expected.  This is evident by the decrease in volumetric losses recently, as volume slows to match areal losses. 

Using a straight linear regression of the NSDIC leads to an ice-free (less than 1 million km2) minimum in 2060.  Various scientific estimates have different, depending on which years are using in this calculation, or which curve best fits the data.  Even this may be too early, as recent minima have not followed the declining trend of the previous decade. 

I agree that this year's early losses are the recent of melting thin ice.  The maximum this year was significantly higher than the past four, and much of that ice was likely thin, first-year ice.  This made for rather easy melting, when temperatures rose.  The melt will likely decline quickly, as this thin ice has mostly melted.  Summer melt will then be on the low side, as the thickness ice will be more resistant.  Due to this prevalence of thick ice, I suspect the minimum this year will be slightly high than last.

without going into details, to some of them i agree, to some i do not agree and again about others i know that they're not correct. There is one thing that deserves to be pointed out to round up the picture independently of the other factors and details that were discussed:

while it's true that the early fast melt is due to thin and, what you forgot to mentione, dispersed ice, the assumption that this doesn't mean more than just that is IMO not 100% spot on.

why?

it would be a valid conclusion if we had  just seen a steep decline from seasonal high to now within a common range.

in fact we did not only see a steep decline, but a steep decline into a significant new all time low for the time of the year and this by  a huge margin and continuing and margin increasing and expected to stay more or less in that zone for some time to come.

i'm sure that the early heat in the system and the added moisture due to more open water and due to lower albedo, also due to more open water, has an impact on max thickness of the remaining sea-ice as we speak. perhaps not in the pole region that won't melt out as a whole anyways, but in the region above 80N and below 85N that may or may not melt out any year from now.

of course facts will ultimately tell us all as usual.
Title: Re: Are 3 dimensions better than 2?
Post by: Viggy on April 05, 2019, 03:21:31 PM
There are two parts to the Arctic.  One part where there is too much heat during the year for ice to survive the melting season, and another part where there is not enough heat during the year to melt the ice.  Extent is the best measure of the shrinking of the zone in which ice can survive, and best measure of the long term trend in reducing the ice, and best predictor of when we will go ice free.  Those who were extrapolating volume/thickness loss around 10 years ago were predicting ice free by about now.  Those who were extrapolating extent predicted that we wouldn't be.  Looks to me like the predictions based on extent were better.

Thickness remembers recent conditions, and encodes information on how warm that part of the Arctic is.  If thickness is very low, that suggests recent temperatures have been warmer, and it is more likely that the ice won't last this specific season.  Thickness is the most important measure for predicting short term changes in ice extent and whether ice will survive the coming melt season.

So true.  Most people do not realize that volumetric losses will always exceed areal losses, due to the added dimension (unless one dimension is held constant).  Hence, a 50% loss in surface area, equates to a 66% loss in volume (and a 30% loss in either dimension constituting the area).  This is simple mathematics (and physics).

I have to assume you are trolling at this point because your argument is that volume lost is greater than area lost because volume has thickness???

And it is impossible to form any simple % correlation between area and volume unless we explicitly know the complete depth profile of the ice and it is somehow uniform across the entire Arctic (which is ludicrous).

‘A lot of people’ may not realize this because apart from using the words ‘mathematics’ and ‘physics’, your argument has no factual basis in either of them.
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 05, 2019, 03:37:53 PM
There are two parts to the Arctic.  One part where there is too much heat during the year for ice to survive the melting season, and another part where there is not enough heat during the year to melt the ice.  Extent is the best measure of the shrinking of the zone in which ice can survive, and best measure of the long term trend in reducing the ice, and best predictor of when we will go ice free.  Those who were extrapolating volume/thickness loss around 10 years ago were predicting ice free by about now.  Those who were extrapolating extent predicted that we wouldn't be.  Looks to me like the predictions based on extent were better.

Thickness remembers recent conditions, and encodes information on how warm that part of the Arctic is.  If thickness is very low, that suggests recent temperatures have been warmer, and it is more likely that the ice won't last this specific season.  Thickness is the most important measure for predicting short term changes in ice extent and whether ice will survive the coming melt season.

So true.  Most people do not realize that volumetric losses will always exceed areal losses, due to the added dimension (unless one dimension is held constant).  Hence, a 50% loss in surface area, equates to a 66% loss in volume (and a 30% loss in either dimension constituting the area).  This is simple mathematics (and physics).

I have to assume you are trolling at this point because your argument is that volume lost is greater than area lost because volume has thickness???

And it is impossible to form any simple % correlation between area and volume unless we explicitly know the complete depth profile of the ice and it is somehow uniform across the entire Arctic (which is ludicrous).

‘A lot of people’ may not realize this because apart from using the words ‘mathematics’ and ‘physics’, your argument has no factual basis in either of them.

What is so difficult to understand?  Yes, volume lost is greater than area, due to thickness.  Unless thickness remains unchanged over the course of decreasing area, volume must decrease to a greater extent.  This is not rocket science, but elementary mathematics, which you dismiss as nonfactual.  May I remind you that volume equals length x height x depth.  If the length x height decreases by a combined 50% (30% each), and depth decreases by a corresponding 30%, volume will decrease by 66%.

Yes, we do not explicitly know the complete depth profile of the ice.  Hence volumetric numbers are calculated from models, which estimate an average sea ice thickness.  This is another reason why two dimensional measurements are better than three dimensional estimates.
Title: Re: Are 3 dimensions better than 2?
Post by: magnamentis on April 05, 2019, 03:38:41 PM
There are two parts to the Arctic.  One part where there is too much heat during the year for ice to survive the melting season, and another part where there is not enough heat during the year to melt the ice.  Extent is the best measure of the shrinking of the zone in which ice can survive, and best measure of the long term trend in reducing the ice, and best predictor of when we will go ice free.  Those who were extrapolating volume/thickness loss around 10 years ago were predicting ice free by about now.  Those who were extrapolating extent predicted that we wouldn't be.  Looks to me like the predictions based on extent were better.

Thickness remembers recent conditions, and encodes information on how warm that part of the Arctic is.  If thickness is very low, that suggests recent temperatures have been warmer, and it is more likely that the ice won't last this specific season.  Thickness is the most important measure for predicting short term changes in ice extent and whether ice will survive the coming melt season.

So true.  Most people do not realize that volumetric losses will always exceed areal losses, due to the added dimension (unless one dimension is held constant).  Hence, a 50% loss in surface area, equates to a 66% loss in volume (and a 30% loss in either dimension constituting the area).  This is simple mathematics (and physics).

I have to assume you are trolling at this point because your argument is that volume lost is greater than area lost because volume has thickness???

And it is impossible to form any simple % correlation between area and volume unless we explicitly know the complete depth profile of the ice and it is somehow uniform across the entire Arctic (which is ludicrous).

‘A lot of people’ may not realize this because apart from using the words ‘mathematics’ and ‘physics’, your argument has no factual basis in either of them.

while i agree with your point, not everyone shooting a bit fast or erring to a certain degree is trolling. i did not have the impression that that was intended but perhaps a bit shot from the hip which i'm also a candidate to do at times and i know that i'm serious, even in error LOL.
Title: Re: Are 3 dimensions better than 2?
Post by: Viggy on April 05, 2019, 04:02:06 PM
What is so difficult to understand?  Yes, volume lost is greater than area, due to thickness.  Unless thickness remains unchanged over the course of decreasing area, volume must decrease to a greater extent.  This is not rocket science, but elementary mathematics, which you dismiss as nonfactual.  May I remind you that volume equals length x height x depth.  If the length x height decreases by a combined 50% (30% each), and depth decreases by a corresponding 30%, volume will decrease by 66%.

Yes, we do not explicitly know the complete depth profile of the ice.  Hence volumetric numbers are calculated from models, which estimate an average sea ice thickness.  This is another reason why two dimensional measurements are better than three dimensional estimates.

So ... im actually a degree’d Aerospace Engineer so even if it was rocket science, I could help you with it 😝

And I am not going to continue a discussion as to why km3 is more than km2. It’s as insane as arguing that acceleration is greater than speed.

Any quantity MUST have the same units for you to be able to compare them. Saying volume is greater than extent is absolutely meaningless because extent is expressed in km2 and to compare it to a volume, km3, we would need to multiply the extent by 0 (thickness), to convert it to the same comparable units.

‘ANY’ km2 x 0 = 0.

And yes, any volume is greater than 0 volume!
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 05, 2019, 05:00:09 PM
What is so difficult to understand?  Yes, volume lost is greater than area, due to thickness.  Unless thickness remains unchanged over the course of decreasing area, volume must decrease to a greater extent.  This is not rocket science, but elementary mathematics, which you dismiss as nonfactual.  May I remind you that volume equals length x height x depth.  If the length x height decreases by a combined 50% (30% each), and depth decreases by a corresponding 30%, volume will decrease by 66%.

Yes, we do not explicitly know the complete depth profile of the ice.  Hence volumetric numbers are calculated from models, which estimate an average sea ice thickness.  This is another reason why two dimensional measurements are better than three dimensional estimates.

So ... im actually a degree’d Aerospace Engineer so even if it was rocket science, I could help you with it 😝

And I am not going to continue a discussion as to why km3 is more than km2. It’s as insane as arguing that acceleration is greater than speed.

Any quantity MUST have the same units for you to be able to compare them. Saying volume is greater than extent is absolutely meaningless because extent is expressed in km2 and to compare it to a volume, km3, we would need to multiply the extent by 0 (thickness), to convert it to the same comparable units.

‘ANY’ km2 x 0 = 0.

And yes, any volume is greater than 0 volume!

Perhaps if it was rocket science, you would be better equipped to handle the issue.  No one is comparing area and volume directly.  The issue is percent lost, which is unit-less.  In this case, the percent area and volume lost can be compared directly.  Having a thickness of zero is only applicable in abstract mathematics, not real world physics.
Title: Re: Are 3 dimensions better than 2?
Post by: Jim Hunt on April 05, 2019, 06:20:43 PM
Having a thickness of zero is only applicable in abstract mathematics, not real world physics.

In real world physics what's the equation for the latent heat of fusion?
Title: Re: Are 3 dimensions better than 2?
Post by: gerontocrat on April 05, 2019, 07:08:42 PM
Having a thickness of zero is only applicable in abstract mathematics, not real world physics.

In real world physics what's the equation for the latent heat of fusion?
See attached.
But as we are talking about sea ice, always a complication...

The content of latent heat in the case of sea ice is a complex one, since thermodynamically it is possible for sea ice and brine to coexist at any temperature, and therefore for sea ice to melt at temperatures other than 0∘C if it is bathed in a suitably concentrated salt solution, such as occurs in the walls of brine cells when brine cell migration is taking place.
Title: Re: Are 3 dimensions better than 2?
Post by: Viggy on April 05, 2019, 08:58:11 PM

Perhaps if it was rocket science, you would be better equipped to handle the issue.  No one is comparing area and volume directly.  The issue is percent lost, which is unit-less.  In this case, the percent area and volume lost can be compared directly.  Having a thickness of zero is only applicable in abstract mathematics, not real world physics.

Ok let’s talk real world -
Arctic extent peaks in late Feb/early March (see Jaxa/nsidc/gerontocrat’s daily update)
Arctic VOLUME peaks in late April/early May (see Piomas thread)

For the next 2 months, Extent will decrease by 10-20% while Volume will increase by 10-20%

Using your own arguments, percentages to define the change and ‘factual elementary mathematics’, volume doesn’t just decrease more when extent decereases (your hypothesis), it actually increases over the given time frame.
Title: Re: Are 3 dimensions better than 2?
Post by: uniquorn on April 05, 2019, 09:25:58 PM
Is it real world when all the volume numbers are models?
Title: Re: Are 3 dimensions better than 2?
Post by: Jim Hunt on April 05, 2019, 10:20:13 PM
See attached.

For the benefit of KK: Q=mL
Title: Re: Are 3 dimensions better than 2?
Post by: b_lumenkraft on April 05, 2019, 10:45:19 PM
Is it real world when all the volume numbers are models?

Models are not real. The observations feed into the models are though.
Title: Re: Are 3 dimensions better than 2?
Post by: jdallen on April 05, 2019, 11:09:01 PM
Is it real world when all the volume numbers are models?

Models are not real. The observations feed into the models are though.
Models are estimates derived from the best available data, complete with confidence levels. Even if imprecise, as year over year the use the same inputs and rules, They can be used to identify trends and changes in scale.
Title: Re: Are 3 dimensions better than 2?
Post by: uniquorn on April 05, 2019, 11:47:19 PM
Agreed. They are estimates until validated.
Title: Re: Are 3 dimensions better than 2?
Post by: Neven on April 05, 2019, 11:48:48 PM
I believe that for kissing 24 dimensions are best.  ;)



it's a maths joke
Title: Re: Are 3 dimensions better than 2?
Post by: uniquorn on April 05, 2019, 11:54:09 PM
23 is prime. I'll go with that.   ;D
Title: Re: Are 3 dimensions better than 2?
Post by: magnamentis on April 06, 2019, 01:41:40 AM
i love this page  :-*
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 06, 2019, 02:54:24 AM
Cannot argue with any of that!
Title: Re: Are 3 dimensions better than 2?
Post by: wili on April 06, 2019, 04:56:46 AM
Since we've entered the field (dimensions?) of romance, may I point out that Edwin Abbott managed to create romance in two dimensions (though the third eventually intrudes):

Quote
Flatland: A Romance of Many Dimensions is a satirical novella by the English schoolmaster Edwin Abbott Abbott, first published in 1884 by Seeley & Co. of London. Written pseudonymously by "A Square",[1] the book used the fictional two-dimensional world of Flatland to comment on the hierarchy of Victorian culture, but the novella's more enduring contribution is its examination of dimensions.

https://en.wikipedia.org/wiki/Flatland

But in romance and in ice dimensions, quality is at least as important as quantity. :)
Title: Re: Are 3 dimensions better than 2?
Post by: epiphyte on April 06, 2019, 11:18:38 AM
> Having a thickness of zero is only applicable in abstract mathematics, not real world physics.

KK  - I do believe that even according to your own arguments, transition between a thickness of 1mm and a thickness of zero is extremely significant, since, it flips the albedo and biases the overall energy equation toward accelerated warming (in summer), or cooling (in winter).

...and regardless of how precisely one can measure it, I hope you would agree that whether one can see or not, change in thickness do occur, and that the warmer it is, the thinner the ice gets.

In this context, I simply don't understand your insistence that the 2D picture is the most important;

    - the area cannot change unless the thickness goes from something to 0
    - If the thickness decreases year-on-year, as it has done for almost three decades straight,
      it makes it more likely that at some point it will go from something to zero.
    - When the thickness _does_ go from something to zero, It makes the planet warmer
      than it otherwise would have been, compounding the problem.



Title: Re: Are 3 dimensions better than 2?
Post by: oren on April 06, 2019, 12:24:41 PM
Well said epiphyte.
Title: Re: Are 3 dimensions better than 2?
Post by: LRC1962 on April 06, 2019, 12:43:16 PM
Earlier I said I would not vote because I much prefer density. KK arguments have changed my mind.
His facts are so not that anyone who has read or studied should shake their heads in disgust.
Ask any microbe, seal, polar bear if there is a difference between an inch of ice and 10 meters of ice and their changing behaviour in the Arctic in the last 20 years would tell you all you need to know that volume matters.
As for KK's assertion that somehow extent and volume are related?  ??? If you check with the Antarctic you would find in the last few years max extent has increased. At the same time though volume has fallen as a result the ice sheets are moving much faster then ever before.
Ice will always form in the dark of winter in the Arctic, but unless things do a 180 there is no question of seeing sometime with  no ice as a minimum, it is only a question of when.
Title: Re: Are 3 dimensions better than 2?
Post by: Jim Hunt on April 06, 2019, 12:49:28 PM
I believe that for kissing 24 dimensions are best.  ;)

I believe that you're inadvertently slipping off topic into the 4th dimension?

Only 2 or 3 are allowed in here!
Title: Re: Are 3 dimensions better than 2?
Post by: Dharma Rupa on April 06, 2019, 01:29:44 PM
I believe that for kissing 24 dimensions are best.  ;)

I believe that you're inadvertently slipping off topic into the 4th dimension?

Only 2 or 3 are allowed in here!

I'm with Neven on this one.
Title: Re: Are 3 dimensions better than 2?
Post by: Dharma Rupa on April 06, 2019, 01:37:04 PM
KK  - I do believe that even according to your own arguments, transition between a thickness of 1mm and a thickness of zero is extremely significant, since, it flips the albedo and biases the overall energy equation toward accelerated warming (in summer), or cooling (in winter).

I don't think the case in winter is nearly that cut and dried.  If the water surface gets warm enough to support a reasonable humidity then fog will form leading to accelerated warming, not cooling, in winter.  It's the difference between a desert climate and a maritime climate.

And I still think we need the 12 dimensions some physicists think there are to reasonably model the ice.  (24 would be good too)

Title: Re: Are 3 dimensions better than 2?
Post by: LRC1962 on April 06, 2019, 01:45:04 PM

And I still think we need the 12 dimensions some physicists think there are to reasonably model the ice.  (24 would be good too)
And less we forget. Chaos Theory! Just when we have things all figured out Chaos jams up the spokes and sends us into orbit.
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 06, 2019, 02:14:50 PM
> Having a thickness of zero is only applicable in abstract mathematics, not real world physics.

KK  - I do believe that even according to your own arguments, transition between a thickness of 1mm and a thickness of zero is extremely significant, since, it flips the albedo and biases the overall energy equation toward accelerated warming (in summer), or cooling (in winter).

...and regardless of how precisely one can measure it, I hope you would agree that whether one can see or not, change in thickness do occur, and that the warmer it is, the thinner the ice gets.

In this context, I simply don't understand your insistence that the 2D picture is the most important;

    - the area cannot change unless the thickness goes from something to 0
    - If the thickness decreases year-on-year, as it has done for almost three decades straight,
      it makes it more likely that at some point it will go from something to zero.
    - When the thickness _does_ go from something to zero, It makes the planet warmer
      than it otherwise would have been, compounding the problem.

Yes, when the thickness decreases from 1mm to zero, it is extremely significant.  However as you stated, it is due to the large albedo change, with resulted from the areal loss. 

I have always maintained that thickness decreases, resulting in thinner ice as the temperature warms.  That is my main argument about volumetric losses being greater (percentage wise) than areal losses.  Others here have contended that volume can increase, while area decreases, due to very specific circumstances.  That may be true, but it is cherry picking the data.

Regarding your individual points:
- thickness must go to 0, in those places where ice area is lost.
- if thickness continues to decrease, at some point it would reach 0
- when thickness goes to 0, the open water would warm, due to more sunlight reaching the surface.  It would cool somewhat during night/winter, but that is unlikely to counter the incoming heat.

As you can see, all these arguments support the 2D approach.  The 3D picture only come into play, when the third dimension goes to 0, but that is because the area goes to 0 also.  Smaller changes in thickness have little overall effect.  Let me pose the question in this manner:  what would have a great effect; 50% loss in area, with no change in thickness, or 50% thickness loss, with no change in area?  After that, a third comparison; 70% loss in both volume and thickness.  In all three cases, volumetric changes are similar.
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 06, 2019, 02:17:43 PM
Sorry, that last part should read 30% loss in each; 70% remaining.
Title: Re: Are 3 dimensions better than 2?
Post by: b_lumenkraft on April 06, 2019, 02:48:06 PM
Yes, when the thickness decreases from 1mm to zero, it is extremely significant.  However as you stated, it is due to the large albedo change, with resulted from the areal loss. 

I would argue even the difference between 1 and 0 cm of ice is not a binary difference. It's also gradually. I don't know at what thickness ice has it's highest albedo, but sure it's not at 1 cm.

You can view it from whatever angle you want, the 3Dness of ice is always to consider.

(btw, talking about 0 cm ice makes my logic engine break! Please, let's not do this anymore)
Title: Re: Are 3 dimensions better than 2?
Post by: Archimid on April 06, 2019, 03:22:11 PM
Thickness is the magnitude of 1 dimension, height.

Area is the magnitude of 2 dimensions, width and length.

Volume is the magnitude of 3 dimensions, height, width and length.

Which one is more important? 42.

ASI is not just a shapeless, massless, inert 3D object in a vacuum.
Title: Re: Are 3 dimensions better than 2?
Post by: Pmt111500 on April 06, 2019, 04:06:07 PM

And I still think we need the 12 dimensions some physicists think there are to reasonably model the ice.  (24 would be good too)
And less we forget. Chaos Theory! Just when we have things all figured out Chaos jams up the spokes and sends us into orbit.

Chaos inserted to (any) system might be the extra dimension we need to figure things out again. Then the weak force needs another one at least. Dark matter is a thing that depends on where the observer is located? How many dimensions do we need? (Glanced at a book of Quantum ElectroDynamics, totally over my head  :) :D
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 06, 2019, 04:10:18 PM
Thickness is the magnitude of 1 dimension, height.

Area is the magnitude of 2 dimensions, width and length.

Volume is the magnitude of 3 dimensions, height, width and length.

Which one is more important? 42.

ASI is not just a shapeless, massless, inert 3D object in a vacuum.

42 definitely!  It has ultimate meaning.

I have to agree that reducing the sea ice to a numerical value has less meaning.  However, that is the data that we have.  Most of these posts are opinions about how we can relate the data to the reality of the Arctic, and its consequences.
Title: Re: Are 3 dimensions better than 2?
Post by: gerontocrat on April 06, 2019, 04:17:49 PM
Yes, when the thickness decreases from 1mm to zero, it is extremely significant.  However as you stated, it is due to the large albedo change, with resulted from the areal loss. 

I would argue even the difference between 1 and 0 cm of ice is not a binary difference. It's also gradually. I don't know at what thickness ice has it's highest albedo, but sure it's not at 1 cm.

You can view it from whatever angle you want, the 3Dness of ice is always to consider.

(btw, talking about 0 cm ice makes my logic engine break! Please, let's not do this anymore)
We are talking about sea ice - winds, currents, swells. Not sure if 1mm or even 1cm ice thickness as significant sheets ever exists. There is not a lot on how sea ice melts, but an awful lot of stuff on the various stages and two main ways sea ice develops. How sea ice developed seems to have importance on the later development of melt ponds (from resulting differences in topography?) and melt ponds is the key to accelerating sea ice melt?

Here is a 114 page pdf on melt ponds. Enjoy a little light reading

https://epic.awi.de/id/eprint/34794/1/Schwarz_2013_diploma_thesis.pdf
Fachbereich VI, Geographie/Geowissenschaften
Fach Umweltmeteorologie
Diplomarbeit
im Studiengang Angewandte Physische Geographie
Quantitative characterisation of sea ice melt stages in the Arctic by means of airborne  photographs
Vorgelegt von: Pascal Schwarz
Matrikelnummer: 888254
Im Doerrengarten 14, 66453 Herbitzheim
Eingereicht am: 06.03.2013
Gutachter:
Univ. Prof. Dr. Gunther Heinemann ¨ , Fach Umweltmeteorologie, Universit¨at Trier
Univ. Prof. Dr. Markus Casper, Fach Physische Geographie, Universit¨at Trier
[/i]
Quote
Abstract
During the melt season, the surface conditions of the Arctic sea ice cover change enormously. The uniform high reflective winter surface transforms to a heterogeneous compound of several surface classes. This change is associated with a strong decrease of the surface albedo, caused by the melting snow cover, the formation of melt ponds and the increase of open water fraction. The goal of this work is to classify images from the MELTEX 2008, NOGRAM 2011 and TIFAX 2010 flight campaigns to determine melt pond parameters, such as concentration, size, size distribution, density, density distribution, shape and shape distribution. These are important quantities for the sea ice atmosphere interaction. A further objective is to evaluate the broadband albedo  measurements of the MELTEX campaign. Overall the work gives a quantitative description of the sea ice melt stages by means of the evaluated quantities mentioned above.

And here is a nice easy one on the formation of sea ice, from NSIDC

https://nsidc.org/cryosphere/seaice/characteristics/formation.html
Ice formation
Quote
As the ocean water begins to freeze, small needle-like ice crystals called frazil form. These crystals are typically 3 to 4 millimeters (0.12 to 0.16 inches) in diameter. Because salt doesn't freeze, the crystals expel salt into the water, and frazil crystals consist of nearly pure fresh water. See also Salinity and Brine.

Sheets of sea ice form when frazil crystals float to the surface, accumulate and bond together. Depending upon the climatic conditions, sheets can develop from grease and congelation ice, or from pancake ice. These processes are described below.

In calm waters, frazil crystals form a smooth, thin form of ice, called grease ice for its resemblance to an oil slick. Grease ice develops into a continuous, thin sheet of ice called nilas. Initially, the sheet is very thin and dark (called dark nilas), becoming lighter as it thickens. Currents or light winds often push the nilas around so that they slide over each other, a process known as rafting. Eventually, the ice thickens into a more stable sheet with a smooth bottom surface, called congelation ice. Frazil ice cannot form in the relatively still waters under sea ice, so only congelation ice developing under the ice sheet can contribute to the continued growth of a congelation ice sheet. Congelation ice crystals are long and vertical because they grow much slower than frazil ice.

If the ocean is rough, the frazil crystals accumulate into slushy circular disks, called pancakes or pancake ice, because of their shape. A signature feature of pancake ice is raised edges or ridges on the perimeter, caused by the pancakes bumping into each other from the ocean waves. If the motion is strong enough, rafting occurs. If the ice is thick enough, ridging occurs, where the sea ice bends or fractures and piles on top of itself, forming lines of ridges on the surface. Each ridge has a corresponding structure, called a keel, that forms on the underside of the ice. Particularly in the Arctic, ridges up to 20 meters (60 feet) thick can form when thick ice deforms. Eventually, the pancakes cement together and consolidate into a coherent ice sheet. Unlike the congelation process, sheet ice formed from consolidated pancakes has a rough bottom surface.

Douglas Adams was right. The answer is 42. Just need to find the right question.
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 06, 2019, 04:47:56 PM
What is 7 million km2 at 6 cm thick?
Title: Re: Are 3 dimensions better than 2?
Post by: be cause on April 06, 2019, 06:00:35 PM
a quick question to the 42 conundrum .. my local village , Caledon , lies between Belfast and Enniskillen .. how far is it from both in miles ? .. smiles b.c. 
Title: Re: Are 3 dimensions better than 2?
Post by: gerontocrat on April 06, 2019, 06:28:12 PM
What is 7 million km2 at 6 cm thick?
Has to be a BOE - 1 million km2 @ 42 cms average thickness, or is it 42 million km2 @ 1 cm thick?
Title: Re: Are 3 dimensions better than 2?
Post by: Juan C. García on April 06, 2019, 06:29:38 PM
It is interesting all the debate that this question has created. From my point of view, 2 dimensions can be useful in some calculations, but we cannot ignore the 3 dimensions in real life. Especially, when we are looking to tell the world how much we have lost of Arctic sea ice.

I have sometimes been tired of my signature on this Forum and I have been thinking on change it. I will post it here, just to keep a record of what it has been all this time.
Title: Re: Are 3 dimensions better than 2?
Post by: oren on April 06, 2019, 06:45:15 PM
Quote
As you can see, all these arguments support the 2D approach.  The 3D picture only come into play, when the third dimension goes to 0, but that is because the area goes to 0 also.  Smaller changes in thickness have little overall effect.  Let me pose the question in this manner:  what would have a great effect; 50% loss in area, with no change in thickness, or 50% thickness loss, with no change in area?  After that, a third comparison; 70% loss in both volume and thickness.  In all three cases, volumetric changes are similar.
KK - it seems you are repeatedly claiming thickness does not matter unless it goes to zero. Only the 2D area/extent matter. I want to verify I understand you correctly.
Let's assume the Arctic sea ice is half the thickness it was in the 1980s. Does this make it more vulnerable to area/extent loss?
There is much less MYI in the arctic these days, and the FYI is thinner than it used to be, due to warmer winters and shorter freezing seasons. Does this matter? Is this important?
Thickness as the 3rd dimension helps predict area/extent losses. Thin ice could melt soon while thick ice is more resilient. Correct or not?
I'll be happy to see clear yes/no answers to these questions.
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 06, 2019, 07:14:40 PM
Quote
As you can see, all these arguments support the 2D approach.  The 3D picture only come into play, when the third dimension goes to 0, but that is because the area goes to 0 also.  Smaller changes in thickness have little overall effect.  Let me pose the question in this manner:  what would have a great effect; 50% loss in area, with no change in thickness, or 50% thickness loss, with no change in area?  After that, a third comparison; 70% loss in both volume and thickness.  In all three cases, volumetric changes are similar.
KK - it seems you are repeatedly claiming thickness does not matter unless it goes to zero. Only the 2D area/extent matter. I want to verify I understand you correctly.
Let's assume the Arctic sea ice is half the thickness it was in the 1980s. Does this make it more vulnerable to area/extent loss?
There is much less MYI in the arctic these days, and the FYI is thinner than it used to be, due to warmer winters and shorter freezing seasons. Does this matter? Is this important?
Thickness as the 3rd dimension helps predict area/extent losses. Thin ice could melt soon while thick ice is more resilient. Correct or not?
I'll be happy to see clear yes/no answers to these questions.

Answers to your specific questions are:  yes, yes, yes, and yes.

All your questions pertain to how thickness might affect future ice melt.  Thinner ice is easier to melt - no doubt.  My contention was that area has a much greater impact on the bigger picture; incoming solar radiation, evapotranspiration, weather, and wildlife.  Thickness has little to no impact in these areas. 
Title: Re: Are 3 dimensions better than 2?
Post by: jdallen on April 06, 2019, 08:07:31 PM
What is 7 million km2 at 6 cm thick?

Impossible.

Straw man question. You will never have 7 million KM2 at 6CM thick, not even as an average.

In fact I consider it dubious to call anything less than 15CM thick anything other than slush.
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 06, 2019, 08:22:03 PM
What is 7 million km2 at 6 cm thick?

Impossible.

Straw man question. You will never have 7 million KM2 at 6CM thick, not even as an average.

In fact I consider it dubious to call anything less than 15CM thick anything other than slush.

lol
Title: Re: Are 3 dimensions better than 2?
Post by: Dharma Rupa on April 06, 2019, 09:15:29 PM
What is 7 million km2 at 6 cm thick?

Impossible.

Straw man question. You will never have 7 million KM2 at 6CM thick, not even as an average.

In fact I consider it dubious to call anything less than 15CM thick anything other than slush.

lol

Thanks for all the fish.
Title: Re: Are 3 dimensions better than 2?
Post by: vox_mundi on April 06, 2019, 09:27:19 PM
As Wolfgang Pauli, Viggy, Jim Hunt and many others have observed: "Das ist nicht nur nicht richtig; es ist nicht einmal falsch!"   (https://en.wikipedia.org/wiki/Not_even_wrong)

See also: Gish Gallop (https://en.wikipedia.org/wiki/Gish_gallop)
Title: Re: Are 3 dimensions better than 2?
Post by: epiphyte on April 06, 2019, 10:23:19 PM
Yes, when the thickness decreases from 1mm to zero, it is extremely significant.  However as you stated, it is due to the large albedo change, with resulted from the areal loss. 

I would argue even the difference between 1 and 0 cm of ice is not a binary difference. It's also gradually. I don't know at what thickness ice has it's highest albedo, but sure it's not at 1 cm.

You can view it from whatever angle you want, the 3Dness of ice is always to consider.

(btw, talking about 0 cm ice makes my logic engine break! Please, let's not do this anymore)

All important points in most contexts, such as observing and modeling real-world behavior.

I left them out to try and keep things simple - IMO adding more nuance (dare I say 'depth') wouldn't help expose the core fallacy.

All of which prompts me to explain why I post here much less often and more tersely than I used to:

    Epiphyte's 1st Law: Don't get suckered into games of logical whack-a-mole. 

    Epiphytes 2nd Law: Don't dig more holes; it emboldens the moles.
Title: Re: Are 3 dimensions better than 2?
Post by: epiphyte on April 06, 2019, 10:38:04 PM


      Which one is more important? 42.


@Arachmid: I fear you misstate the question. All true HHGTTG scholars know that the true
question is "What is six times nine?"
 

      42 definitely!  It has ultimate meaning.


That, at least, we can agree on.

(Aside - We can therefore conclude that the world only makes sense in base 13)
Title: Re: Are 3 dimensions better than 2?
Post by: Viggy on April 06, 2019, 11:11:02 PM
As Wolfgang Pauli, Viggy, Jim Hunt and many others have observed: "Das ist nicht nur nicht richtig; es ist nicht einmal falsch!"   (https://en.wikipedia.org/wiki/Not_even_wrong)

See also: Gish Gallop (https://en.wikipedia.org/wiki/Gish_gallop)

I finally learnt something in this thread!

Also, I think both the pro and con sides can agree that due to the nature of this thread, it will continue on circuitously till we have all burnt out far too much intellectual capital. There will be no agreement or conclusions here. Lets move on to more fruitful conversations.
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 06, 2019, 11:33:10 PM
As Wolfgang Pauli, Viggy, Jim Hunt and many others have observed: "Das ist nicht nur nicht richtig; es ist nicht einmal falsch!"   (https://en.wikipedia.org/wiki/Not_even_wrong)

See also: Gish Gallop (https://en.wikipedia.org/wiki/Gish_gallop)

I finally learnt something in this thread!

Also, I think both the pro and con sides can agree that due to the nature of this thread, it will continue on circuitously till we have all burnt out far too much intellectual capital. There will be no agreement or conclusions here. Lets move on to more fruitful conversations.

Agreed.  We will never come to agreement on matters of opinion.
Title: Re: Are 3 dimensions better than 2?
Post by: LRC1962 on April 07, 2019, 05:02:24 AM
For those of you who agree to some extent that thin ice is very little different to thick ice in regards to heat this study begs to differ. https://www.arctictoday.com/thinning-arctic-sea-ice-influences-atmosphere-spinoff-effects-eurasia-study-says/
Quote
Low concentration of ice – spotty coverage of the water’s surface that leaves large areas of open water – will still play a much bigger role in creating warm temperatures, the new study finds. But if ice is thin, the amount of heat that seeps through it can cause up to a third of the warming that is caused by low ice concentration, the study found.
most heat still is most important in open water, but up to a third goes through thin ice.
Direct weather influence.
Quote
While it found that thinner ice does influence the lower and middle levels of the atmosphere, potentially shifting the jet stream southward, the study found “no significant response” to loss of ice thickness in the stratosphere. That upper level is the site of the polar vortex, the counterclockwise flow of air around the low-pressure system above the North Pole. The study did find that lower sea ice concentration influences the stratosphere and strengthens the polar vortex.
Thin ice effects lower and middle levels of atmosphere. Those are where you get the surface winds and rain/snow from.
This is not opinion it is science. Thinning ice does effect heat, weather, wildlife ....
Anyone remember the green ice that was seen a few years back? It was not an illusion. Not opinion.
Title: Re: Are 3 dimensions better than 2?
Post by: Pmt111500 on April 07, 2019, 05:06:13 AM
(Aside - We can therefore conclude that the world only makes sense in base 13)

Is this eposode of "measurement error paradox" aka "accuracy dependent on wavelenght" sponsored by SquareSpace?

LRC1962:
Are you saying that thick-walled igloos keep the eskimos warmer than thin-walled? This depends also on how well these are construced, i.e. thick walls do not help much if the roof is 1cm thick. Tested this with snow, which is by the way whiter than ice, although still ice. I'm tempted to use word "allotrope" on millions of different snowflakes, but the difference isn't fundamental in this case, I think. If what you say is true, thicker insulating material might be noticed off the loss of heat flow from radiating material behind that. This might mean we can measure the thickness in the middle of a wood plank by other means than drilling a hole and a measuring tape?

("Add extra dimensions as is needed", world-builders handbook)

What is the inertia of a 2d-layer? How would one go about constructing one? Are f.e. black holes 2d?
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 07, 2019, 05:36:55 AM
For those of you who agree to some extent that thin ice is very little different to thick ice in regards to heat this study begs to differ. https://www.arctictoday.com/thinning-arctic-sea-ice-influences-atmosphere-spinoff-effects-eurasia-study-says/
Quote
Low concentration of ice – spotty coverage of the water’s surface that leaves large areas of open water – will still play a much bigger role in creating warm temperatures, the new study finds. But if ice is thin, the amount of heat that seeps through it can cause up to a third of the warming that is caused by low ice concentration, the study found.
most heat still is most important in open water, but up to a third goes through thin ice.
Direct weather influence.
Quote
While it found that thinner ice does influence the lower and middle levels of the atmosphere, potentially shifting the jet stream southward, the study found “no significant response” to loss of ice thickness in the stratosphere. That upper level is the site of the polar vortex, the counterclockwise flow of air around the low-pressure system above the North Pole. The study did find that lower sea ice concentration influences the stratosphere and strengthens the polar vortex.
Thin ice effects lower and middle levels of atmosphere. Those are where you get the surface winds and rain/snow from.
This is not opinion it is science. Thinning ice does effect heat, weather, wildlife ....
Anyone remember the green ice that was seen a few years back? It was not an illusion. Not opinion.

Yes, but the study concluded by stating, “low concentrations of ice - spotty coverage of the water’s surface that leaves large areas of open water - will still play a much bigger role in creating warm temperatures.”
Title: Re: Are 3 dimensions better than 2?
Post by: Tor Bejnar on April 07, 2019, 07:12:35 AM
1) I've been surprised how much fervor has gone into this thread.
2) I'm grateful to KK for "sticking to his guns"
3) "Are 3 dimensions better than 2?":  Better for what?

I voted for "3" because I was considering things like comparing 1980 Arctic ice health with today - the ice volume difference 'really matters'.  Like, really matters a great deal.

This doesn't mean that "2 dimensions" isn't highly significant for many aspects of Arctic climate dynamics, fairly independent of whether the ice is 2 meters thick or 10 meters thick.  Knowing only a "2 dimensions" number is certainly "better" for calculating albedo than knowing only a "3 dimensions" number.  (Does that 1,000,000 km3 cover 500,000 km2 or just 5,000 km2?)

Yes, ice that is thinner than a meter or two (and more so when thinner) is relatively transparent, allowing for solar-induced bottom melt and algae growth, and may be more likely to be rotten late in the melting season allowing a polar bear to either catch a seal or fall through and have to swim.  And then there is how waves, etc. affect thinner ice.  But all this just begs the question.  I don't think the thread's question is "Is knowing thickness better than knowing area?"
Title: Re: Are 3 dimensions better than 2?
Post by: epiphyte on April 07, 2019, 07:18:06 AM
A last parting thought, before I withdraw from this onanistic thread:

Which is more insightful - arithmetic, or calculus?

er...
That's it.

Title: Re: Are 3 dimensions better than 2?
Post by: wdmn on April 07, 2019, 07:20:17 AM
1) I've been surprised how much fervor has gone into this thread.
2) I'm grateful to KK for "sticking to his guns"
3) "Are 3 dimensions better than 2?":  Better for what?

I voted for "3" because I was considering things like comparing 1980 Arctic ice health with today - the ice volume difference 'really matters'.  Like, really matters a great deal.

This doesn't mean that "2 dimensions" isn't highly significant for many aspects of Arctic climate dynamics, fairly independent of whether the ice is 2 meters thick or 10 meters thick.  Knowing only a "2 dimensions" number is certainly "better" for calculating albedo than knowing only a "3 dimensions" number.  (Does that 1,000,000 km3 cover 500,000 km2 or just 5,000 km2?)

Yes, ice that is thinner than a meter or two (and more so when thinner) is relatively transparent, allowing for solar-induced bottom melt and algae growth, and may be more likely to be rotten late in the melting season allowing a polar bear to either catch a seal or fall through and have to swim.  And then there is how waves, etc. affect thinner ice.  But all this just begs the question.  I don't think the thread's question is "Is knowing thickness better than knowing area?"

Thanks Tor; great post. We need to always ask "better for what," when judging between two approaches.
Title: Re: Are 3 dimensions better than 2?
Post by: Pmt111500 on April 07, 2019, 10:30:25 AM
A last parting thought, before I withdraw from this onanistic thread:

Which is more insightful - arithmetic, or calculus?

er...
That's it.

Ah, beauty is just surface, you need to function as well so 3d might be better.
Title: Re: Are 3 dimensions better than 2?
Post by: magnamentis on April 07, 2019, 12:35:53 PM
A last parting thought, before I withdraw from this onanistic thread:

Which is more insightful - arithmetic, or calculus?

er...
That's it.

somehow funny, onanistic and once done opting out, fits that pattern quite well LOL

propably a smart move before things get worn out, into repeating patterns and therefore boring.

however that may be, i definitely enjoyed the conversation thus far because things were showing that i love so much, mainly yours and other participant's mental power.
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 07, 2019, 03:20:23 PM
1) I've been surprised how much fervor has gone into this thread.
2) I'm grateful to KK for "sticking to his guns"
3) "Are 3 dimensions better than 2?":  Better for what?

I voted for "3" because I was considering things like comparing 1980 Arctic ice health with today - the ice volume difference 'really matters'.  Like, really matters a great deal.

This doesn't mean that "2 dimensions" isn't highly significant for many aspects of Arctic climate dynamics, fairly independent of whether the ice is 2 meters thick or 10 meters thick.  Knowing only a "2 dimensions" number is certainly "better" for calculating albedo than knowing only a "3 dimensions" number.  (Does that 1,000,000 km3 cover 500,000 km2 or just 5,000 km2?)

Yes, ice that is thinner than a meter or two (and more so when thinner) is relatively transparent, allowing for solar-induced bottom melt and algae growth, and may be more likely to be rotten late in the melting season allowing a polar bear to either catch a seal or fall through and have to swim.  And then there is how waves, etc. affect thinner ice.  But all this just begs the question.  I don't think the thread's question is "Is knowing thickness better than knowing area?"

Thank you Tor,

What has surprised me is how much antagonism and insults have been directed at me.  Just because they disagree!  From the voting, it is apparent that I am in the minority, but not the only one.  I have presented my argument, and been asked to defend it numerous times.  The lengths to which some posters have gone to try and refute my arguments have been staggering.  Perhaps I have hit a nerve, or some other issue that they have been unable to resolve, and taking it out on me.  I don’t know. I have yet to read any post that has given me any reason to change my views.  If someone were to prove me wrong, I will be the first to admit it.  However, unless someone presents compelling evidence contradicting my statements, I see no reason to change my views. 
Title: Re: Are 3 dimensions better than 2?
Post by: Archimid on April 07, 2019, 03:49:05 PM
KK, what are your views? They are all over the place. Do you still believe that volume and thickness don't matter?

Also do you understand the difference between thickness and volume? You seem to be using them as interchangeable.

To me it seems like you want to focus in extent because it tells the story you want to hear. To do that you must ignore thickness and volume because they tell a very different story than just area.

Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 07, 2019, 04:12:02 PM
KK, what are your views? They are all over the place. Do you still believe that volume and thickness don't matter?

Also do you understand the difference between thickness and volume? You seem to be using them as interchangeable.

To me it seems like you want to focus in extent because it tells the story you want to hear. To do that you must ignore thickness and volume because they tell a very different story than just area.
Archimid,
I have never said that thickness and volume do not matter.  That has been the straw man argument used to refute my contention that extent is the better measure.  My views have not changed on this.  You seem to be of the mistaken belief otherwise (perhaps you are listening to those who made those false claims).  If you still have issues, I suggest you read what NSIDC has to say about the issue, and why they feel extent is the better measure.  It is not a matter of belief, but scientific evidence.
Title: Re: Are 3 dimensions better than 2?
Post by: Archimid on April 07, 2019, 04:40:25 PM
Quote
I have never said that thickness and volume do not matter.

That's the impression I got after reading these:

Quote
Yes, but that third dimension, thickness, is several orders of magnitude smaller than the other two.  Hence, the third dimension forces have much less influence on the total makeup than the other two.
...
The factors influencing thickness, like wave action, are small compared to those acting on the overall area, sunlight and seawater.  Thickness changes does not drive the sea ice, rather they occur through these other factors.
...
Smaller changes in thickness have little overall effect.
...
Thickness has little to no impact in these areas.
 


Let's reset.

Quote
and why they feel extent is the better measure.

A better measure of what? Be specific. What is the question that Area best answers?
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 07, 2019, 06:16:58 PM
Quote
I have never said that thickness and volume do not matter.

That's the impression I got after reading these:

Quote
Yes, but that third dimension, thickness, is several orders of magnitude smaller than the other two.  Hence, the third dimension forces have much less influence on the total makeup than the other two.
...
The factors influencing thickness, like wave action, are small compared to those acting on the overall area, sunlight and seawater.  Thickness changes does not drive the sea ice, rather they occur through these other factors.
...
Smaller changes in thickness have little overall effect.
...
Thickness has little to no impact in these areas.
 


Let's reset.

Quote
and why they feel extent is the better measure.

A better measure of what? Be specific. What is the question that Area best answers?

Less is not the same as none.

The short answer is the state of the Arctic.   For a more detailed answer, please read my previous posts.
Title: Re: Are 3 dimensions better than 2?
Post by: Archimid on April 07, 2019, 06:44:36 PM
Quote
Less is not the same as none

I could've sworn that you were implying that the impact of volume and thickness on the "state of the Arctic" was so small as to be irrelevant.

So let me ask you this. Currently the Arctic is at record low extent ( by a lot) but volume and thickness are not record low.  Is this the worst state the Arctic has ever been?
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 07, 2019, 06:58:10 PM
Quote
Less is not the same as none

I could've sworn that you were implying that the impact of volume and thickness on the "state of the Arctic" was so small as to be irrelevant.

So let me ask you this. Currently the Arctic is at record low extent ( by a lot) but volume and thickness are not record low.  Is this the worst state the Arctic has ever been?
[/quote

No, just much smaller.  Someone else said irrelevant.

In a snapshot, just looking at this date, the answer would be yes.  However, on any given date, several years in the past decade can state that claim (2018 has numerous dates).  I think we need to examine how the ice grows and shrinks each year, and assess the overall changes.  For instance, last summer showed greater minimum extent than previous years, and this year showed greater maximum extent.  If ice loss slows, and reaches a similar level as last year, then my answer would be no.  Overall, the Arctic appears to have reached a new equilibrium, where ice melting in summer is replaced by new ice in the winter, but multiyear ice does not change appreciably.  I suspect this will continue, until the next force pushes the system into a new state. 
Title: Re: Are 3 dimensions better than 2?
Post by: Archimid on April 07, 2019, 07:41:13 PM
Quote
No, just much smaller.  Someone else said irrelevant.

So you think the influence of volume and thickness on the "state of the Arctic" are not so small as to be irrelevant, nice. We are getting somewhere. Volume and thickness are relevant to the "state of the Arctic". We agree on that.

How relevant? We disagree enormously.

Quote
In a snapshot, just looking at this date, the answer would be yes.

My answer would be no. This is not the worst state the Arctic has ever been. The volume of ice on the Arctic is higher than in 2017, thus more energy will be needed to melt the remaining ice than in 2017, even when the extent is lower.


Quote
I suspect this will continue, until the next force pushes the system into a new state.

Like for example, pacification of the inner Arctic basin. Ice will still form, increasing Area numbers during the cold Arctic winter but Area hides the fact that it is thin, salty, late to form and early to melt ice.


Title: Re: Are 3 dimensions better than 2?
Post by: Neven on April 07, 2019, 11:33:27 PM
If you still have issues, I suggest you read what NSIDC has to say about the issue, and why they feel extent is the better measure.  It is not a matter of belief, but scientific evidence.

Out of curiosity: Where does the NSIDC say that extent is a better measure than volume/thickness?
Title: Re: Are 3 dimensions better than 2?
Post by: magnamentis on April 08, 2019, 02:24:10 AM
putting aside for a moment the questin which is better ( it's almost like asking wether a circle is rounder than a triangle) perhaps the linked post helps to at least understand the significance of thickness and how large a difference it makes at the end.

at least this is the case if we agree that after first BOE that last a i bit longer than a few days not much will be as it was before that event.

https://forum.arctic-sea-ice.net/index.php/topic,2348.msg194274.html#msg194274
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 08, 2019, 02:51:06 AM
If you still have issues, I suggest you read what NSIDC has to say about the issue, and why they feel extent is the better measure.  It is not a matter of belief, but scientific evidence.

Out of curiosity: Where does the NSIDC say that extent is a better measure than volume/thickness?

“When the ice melts, the polar regions have less of a reflective surface.  More hear is absorbed, which causes more warming.”

and

“Roughly half of the heat exchange occurs through openings in the ice.”

https://nsidc.org/cryosphere/seaice/environment/global_climate.html

Also,
“Scientists tend to focus on Arctic sea ice extent more closely than other aspects of sea ice because satellites measure extent more accurately than they do other measurements, such as thickness.”

https://nsidc.org/cryosphere/quickfacts/seaice.html
Title: Re: Are 3 dimensions better than 2?
Post by: oren on April 08, 2019, 04:18:08 AM
Quote
As you can see, all these arguments support the 2D approach.  The 3D picture only come into play, when the third dimension goes to 0, but that is because the area goes to 0 also.  Smaller changes in thickness have little overall effect.  Let me pose the question in this manner:  what would have a great effect; 50% loss in area, with no change in thickness, or 50% thickness loss, with no change in area?  After that, a third comparison; 70% loss in both volume and thickness.  In all three cases, volumetric changes are similar.
KK - it seems you are repeatedly claiming thickness does not matter unless it goes to zero. Only the 2D area/extent matter. I want to verify I understand you correctly.
Let's assume the Arctic sea ice is half the thickness it was in the 1980s. Does this make it more vulnerable to area/extent loss?
There is much less MYI in the arctic these days, and the FYI is thinner than it used to be, due to warmer winters and shorter freezing seasons. Does this matter? Is this important?
Thickness as the 3rd dimension helps predict area/extent losses. Thin ice could melt soon while thick ice is more resilient. Correct or not?
I'll be happy to see clear yes/no answers to these questions.

Answers to your specific questions are:  yes, yes, yes, and yes.

All your questions pertain to how thickness might affect future ice melt.  Thinner ice is easier to melt - no doubt.  My contention was that area has a much greater impact on the bigger picture; incoming solar radiation, evapotranspiration, weather, and wildlife.  Thickness has little to no impact in these areas.
First, I am happy we've managed to establish an agreement on the points of importance of thickness when discussing future ice melt, after the casual remarks I've read in the melting season thread and perhaps misunderstood as claiming the contrary. For that this thread was worth it despite the off-topic comments flying around.

Certainly current area has a big impact on current conditions (evapotranspiration, weather, and wildlife, also dampening of waves). My focus at this time of year though is on impacts for the rest of the melting season. Incoming solar radiation (the Albedo-Warming Potential) is very important but its effects are still subdued and are geographically placed outside the Inner Arctic Basin at this time. So I turn to current thickness as the wildcard that can precondition a melting season - both the thickness and distribution of MYI, and the thickness of FYI especially in the Inner Basin.
I will add that at the beginning of the melting season extent and area are only slightly different from year to year percentage-wise (2%? 5%?), while thickness could be more variable. When trying to assess whether this will be a record melting year or not, current area/extent don't tell much - the rankings are quite volatile from week to week, they have relatively low correlation to September area/extent, and there is the case of 2012 that went from high to record low. A low April area/extent certainly increases risk but the change is not huge.
OTOH an abnormally low thickness could be off even by 20% compared to average years, and could greatly increase the risk of a record melting season. So I find thickness in April to be much more important than area in April to forecasting area in September. It's true that thickness is not known with the same precision as area, but it's not entirely unknown. There's SMOS for thin ice <0.5M, there's Cryosat, there's PIOMAS which although a model has been quite validated over the years, there's Operation IceBridge at this time of year, and hopefully there will soon be that new satellite that measures freeboard with precision. So I will keep my eye on April thickness whenever I can find it.
(Of course, the biggest factor affecting the melting season is the weather - cloudiness, air temps, ice transport and whatever other factors. But all of this is unknown at this point.)
Title: Re: Are 3 dimensions better than 2?
Post by: Jim Hunt on April 08, 2019, 11:37:06 AM
“Scientists tend to focus on Arctic sea ice extent more closely than other aspects of sea ice because satellites measure extent more accurately than they do other measurements, such as thickness.”

So? Here's the NSIDC's sea ice thermodynamics section:

https://nsidc.org/cryosphere/seaice/processes/growth_melt_cycle.html
Title: Re: Are 3 dimensions better than 2?
Post by: Neven on April 08, 2019, 11:39:51 AM
If you still have issues, I suggest you read what NSIDC has to say about the issue, and why they feel extent is the better measure.  It is not a matter of belief, but scientific evidence.

Out of curiosity: Where does the NSIDC say that extent is a better measure than volume/thickness?

“When the ice melts, the polar regions have less of a reflective surface.  More hear is absorbed, which causes more warming.”

and

“Roughly half of the heat exchange occurs through openings in the ice.”

https://nsidc.org/cryosphere/seaice/environment/global_climate.html

Also,
“Scientists tend to focus on Arctic sea ice extent more closely than other aspects of sea ice because satellites measure extent more accurately than they do other measurements, such as thickness.”

https://nsidc.org/cryosphere/quickfacts/seaice.html

They don't say it's better, they say it's measured more accurately.
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 08, 2019, 01:31:42 PM
If you still have issues, I suggest you read what NSIDC has to say about the issue, and why they feel extent is the better measure.  It is not a matter of belief, but scientific evidence.

Out of curiosity: Where does the NSIDC say that extent is a better measure than volume/thickness?

“When the ice melts, the polar regions have less of a reflective surface.  More hear is absorbed, which causes more warming.”

and

“Roughly half of the heat exchange occurs through openings in the ice.”

https://nsidc.org/cryosphere/seaice/environment/global_climate.html

Also,
“Scientists tend to focus on Arctic sea ice extent more closely than other aspects of sea ice because satellites measure extent more accurately than they do other measurements, such as thickness.”

https://nsidc.org/cryosphere/quickfacts/seaice.html

They don't say it's better, they say it's measured more accurately.

Not in so many words, no.  However, they emphasize the importance of ice cover over other attributes in the total system.
Title: Re: Are 3 dimensions better than 2?
Post by: Jim Hunt on April 08, 2019, 02:22:28 PM
However, they emphasize the importance of ice cover over other attributes in the total system.

No they don't. At the risk of repeating myself:

https://nsidc.org/cryosphere/icelights/2011/08/getting-beneath-ice

Quote
NSIDC reports ice extent, a two-dimensional measure of the Arctic Ocean’s ice cover. But sea ice extent tells only part of the story: sea ice is not all flat like a sheet of paper....

Scientists want to know not just how far the ice extends, but also how deep and thick it is, because thinner ice is more vulnerable to summer melt.
Title: Re: Are 3 dimensions better than 2?
Post by: Pmt111500 on April 08, 2019, 02:31:39 PM
I'll mention the possibility of 2,7 dimensions as a description of dry water ice and 2,5 - 2,9 for wet water ice depending on external temperature and exit this somewhat esoteric thread. Thanks.
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 08, 2019, 03:05:42 PM
However, they emphasize the importance of ice cover over other attributes in the total system.

No they don't. At the risk of repeating myself:

https://nsidc.org/cryosphere/icelights/2011/08/getting-beneath-ice

Quote
NSIDC reports ice extent, a two-dimensional measure of the Arctic Ocean’s ice cover. But sea ice extent tells only part of the story: sea ice is not all flat like a sheet of paper....

Scientists want to know not just how far the ice extends, but also how deep and thick it is, because thinner ice is more vulnerable to summer melt.

Exactly what are you gleaning out of this report to support your claims, besdeds they are trying to measure thickness more accuratey?
Title: Re: Are 3 dimensions better than 2?
Post by: jdallen on April 08, 2019, 05:38:32 PM
However, they emphasize the importance of ice cover over other attributes in the total system.

No they don't. At the risk of repeating myself:

https://nsidc.org/cryosphere/icelights/2011/08/getting-beneath-ice

Quote
NSIDC reports ice extent, a two-dimensional measure of the Arctic Ocean’s ice cover. But sea ice extent tells only part of the story: sea ice is not all flat like a sheet of paper....

Scientists want to know not just how far the ice extends, but also how deep and thick it is, because thinner ice is more vulnerable to summer melt.

Exactly what are you gleaning out of this report to support your claims, besdeds they are trying to measure thickness more accuratey?
... that they consider thickness/volume a key metric for understanding Arctic system behavior....
Title: Re: Are 3 dimensions better than 2?
Post by: Jim Hunt on April 09, 2019, 11:37:18 AM
Exactly what are you gleaning out of this report

What JD said.

Plus I'm curious why you apparently think one page on the NSIDC web site constitutes "scientific evidence" whereas a couple of other pages do not.
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 09, 2019, 02:13:17 PM
Exactly what are you gleaning out of this report

What JD said.

Plus I'm curious why you apparently think one page on the NSIDC web site constitutes "scientific evidence" whereas a couple of other pages do not.

Not sure how you came to that conclusion, especially since I referenced much of the entire website.  Your link just mentions how scientists are attempting to more accurately measure ice thickness.  Nothing in your link supports your claim that they feel that thickness is a more important attribute than extent.  Could it just be wishful thinking on your part?
Title: Re: Are 3 dimensions better than 2?
Post by: Jim Hunt on April 10, 2019, 09:23:50 PM
Since I referenced much of the entire website.

I must have blinked and missed that.

Quote
Your link just mentions how scientists are attempting to more accurately measure ice thickness.


Plus "sea ice extent tells only part of the story". Did you blink and miss that?

Quote
Nothing in your link supports your claim that they feel that thickness is a more important attribute than extent.

Where did I claim that?

Quote
Could it just be wishful thinking on your part?

Nope.
Title: Re: Are 3 dimensions better than 2?
Post by: Klondike Kat on April 11, 2019, 01:26:03 PM
Since I referenced much of the entire website.

I must have blinked and missed that.

Apparently

Quote
Your link just mentions how scientists are attempting to more accurately measure ice thickness.


Plus "sea ice extent tells only part of the story".

Obviously.

Quote
Nothing in your link supports your claim that they feel that thickness is a more important attribute than extent.

Where did I claim that?

Seems otherwise

Quote
Could it just be wishful thinking on your part?

Nope.

Good.  I would hope that you are being objective.
Title: Re: Are 3 dimensions better than 2?
Post by: Tom_Mazanec on April 17, 2019, 09:36:20 PM
While we're talking about area vs volume, here is some results (using Earth's gravity) of ice mass and sea level rise, which should give us a volume clue:
https://phys.org/news/2019-04-earth-gravity-reveals-climate.html
BTW, the link comes from the Dieoff reddit...so that is who cliffhanger1983 is.
Title: Re: Are 3 dimensions better than 2?
Post by: Neven on April 17, 2019, 09:42:13 PM
Wrong thread. GRACE doesn't measure Arctic sea ice volume.
Title: Re: Are 3 dimensions better than 2?
Post by: Tom_Mazanec on April 17, 2019, 09:46:55 PM
Well neven, I thought that if you see that, say, the Antarctic icecap is 500 billion tons lighter gravitational pull, it means 500 billion tons of ice melted, and that means around 500 billion cubic meters (a cubic meter of ice weighs about a ton, right?) less ice volume.
I am trying not to start new threads, so I thought I should post it here.
Title: Re: Are 3 dimensions better than 2?
Post by: Neven on April 17, 2019, 10:11:12 PM
The discussion here is related to Arctic sea ice, not to Antarctic land ice. GRACE has been and still is mentioned in many threads, such as the Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE thread (https://forum.arctic-sea-ice.net/index.php/topic,2205.900.html).
Title: Re: Are 3 dimensions better than 2?
Post by: 5to10 on April 17, 2019, 11:23:13 PM
The discussion here is related to Arctic sea ice, not to Antarctic land ice. GRACE has been and still is mentioned in many threads, such as the Ice Apocalypse - MULTIPLE METERS SEA LEVEL RISE thread (https://forum.arctic-sea-ice.net/index.php/topic,2205.900.html).

That account is disinfo or just a straight up troll. They are well aware of what they're doing here and well aware this is the wrong thread for what they are posting.
Title: Re: Are 3 dimensions better than 2?
Post by: be cause on April 18, 2019, 12:37:02 AM
thanks 5to10 .. I was hoping Neven would have recognized the signs .. b.c.
Title: Re: Are 3 dimensions better than 2?
Post by: Tom_Mazanec on April 18, 2019, 12:50:25 AM
Sorry...as I said, I thought this was the best place for it.
Title: Re: Are 3 dimensions better than 2?
Post by: magnamentis on April 18, 2019, 01:30:42 AM
Sorry...as I said, I thought this was the best place for it.

And there it is, within five minutes of me mentioning it on the other thread. The song and dance routine.

What, I ain't doin' nothin' ..."

we are gaining momentum, just a matter of time, ignore list helps to suffer less for the moment

;) ;) ;)

Title: Re: Are 3 dimensions better than 2?
Post by: Rod on April 18, 2019, 07:16:49 AM
The trolls are getting strong on this forum.  There is another one that has been active lately that I think is Daniel B. 

I'm not going to name and shame because I can't prove it, but it makes it hard to follow the science threads when sophisticated trolls are trying to disrupt the conversation. 
Title: Re: Are 3 dimensions better than 2?
Post by: b_lumenkraft on April 18, 2019, 07:36:30 AM
I'm not going to name and shame

Hello? But that's what you just did, Rob.

I don't think Tom is a troll. They are having difficulties finding out how this forum ticks.

My advice for Tom would have been to lurk here for a while before posting, but there is no law that demands that.

And for how i see it, the disruption is mainly caused by people responding to Tom, not by Toms posts.
Title: Re: Are 3 dimensions better than 2?
Post by: Pmt111500 on April 18, 2019, 08:21:51 AM
Whataboutism-filter would be grate but I don't think it's possible to construct one as of yet
Title: Re: Are 3 dimensions better than 2?
Post by: Neven on April 18, 2019, 09:51:23 AM
I had hoped this thread would slowly disappear. I'm going to give the process a nudge by locking it. If anyone wants to see it re-opened for a continuation of this fascinating discussion  ::) , write me a PM.