A binary poll might illuminate the consensus.
So, did sea ice increase or decrease in that period? Which dimensions will you choose to use to make the call?
So, did sea ice increase or decrease in that period? Which dimensions will you choose to use to make the call?
3 dimensions are real, 2 dimensions is just a concept, an idea, an abstract of reality.
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.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.
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.
melt ponds
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?
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
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.
This should come as no surprise to those who have followed my posts.
The albedo effect is based on two dimensions;
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
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.
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.
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.
Do you really think that a 90% drop in thickness can even compare to a 90% drop in extent (or area)?
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.
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.
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.
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.
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).
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.
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.
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!
Having a thickness of zero is only applicable in abstract mathematics, not real world physics.
See attached.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?
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.
See attached.
Is it real world when all the volume numbers are models?
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.Is it real world when all the volume numbers are models?
Models are not real. The observations feed into the models are though.
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.
I believe that for kissing 24 dimensions are best. ;)
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!
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 less we forget. Chaos Theory! Just when we have things all figured out Chaos jams up the spokes and sends us into orbit.
And I still think we need the 12 dimensions some physicists think there are to reasonably model the ice. (24 would be good too)
> 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.
And less we forget. Chaos Theory! Just when we have things all figured out Chaos jams up the spokes and sends us into orbit.
And I still think we need the 12 dimensions some physicists think there are to reasonably model the ice. (24 would be good too)
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.
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?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)
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.
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.
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?
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.
QuoteAs 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.
What is 7 million km2 at 6 cm thick?
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.
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
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)
Which one is more important? 42.
42 definitely! It has ultimate meaning.
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)
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.
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.
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.
(Aside - We can therefore conclude that the world only makes sense in base 13)
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/QuoteLow 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.QuoteWhile 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.
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?"
A last parting thought, before I withdraw from this onanistic thread:
Which is more insightful - arithmetic, or calculus?
er...
That's it.
A last parting thought, before I withdraw from this onanistic thread:
Which is more insightful - arithmetic, or calculus?
er...
That's it.
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?"
KK, what are your views? They are all over the place. Do you still believe that volume and thickness don't matter?Archimid,
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.
I have never said that thickness and volume do not matter.
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.
and why they feel extent is the better measure.
QuoteI have never said that thickness and volume do not matter.
That's the impression I got after reading these:QuoteYes, 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.Quoteand 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
QuoteLess 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.
No, just much smaller. Someone else said irrelevant.
In a snapshot, just looking at this date, the answer would be yes.
I suspect this will continue, until the next force pushes the system into a new state.
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.
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?
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.QuoteAs 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.
“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.”
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
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.
However, they emphasize the importance of ice cover over other attributes in the total system.
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.
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-iceQuoteNSIDC 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.
... that they consider thickness/volume a key metric for understanding Arctic system behavior....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-iceQuoteNSIDC 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?
Exactly what are you gleaning out of this report
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.
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?
Since I referenced much of the entire website.
I must have blinked and missed that.
ApparentlyQuoteYour link just mentions how scientists are attempting to more accurately measure ice thickness.
Plus "sea ice extent tells only part of the story".
Obviously.QuoteNothing in your link supports your claim that they feel that thickness is a more important attribute than extent.
Where did I claim that?
Seems otherwiseQuoteCould it just be wishful thinking on your part?
Nope.
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).
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' ..."
I'm not going to name and shame