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Messages - binntho

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1
Arctic sea ice / Re: Arctic energy balance
« on: Today at 02:32:05 PM »
While trying to get my head around the radiative thermal transfer thing, I was reminded that when we say that a body emits 500 W/m2 of thermal energy, that translates into 500 Joules/second.

So a typical westerner at 2 m2 and 500 W/m2 would lose 60*60*24*500 Joules per day, or 43.200 kJ, or 10.000 Calories. Through radiative thermal transfer alone. Not counting heat loss through conduction or convection, not counting movement and metabolism and brain activity.

Edit: Not much brain activity here, the numbers should of course have been doubled since the well-fed westerner comes in at 2 m2. So 20.000 Calories lost daily to thermal radiation.

2
Arctic sea ice / Re: Arctic energy balance
« on: Today at 02:25:55 PM »
Binntho heat radiation depends on the difference in temperature. Of course you can't feel other people when you are the same temperature. But the ice is at 0o.

I'm not at all sure that heat radiation depends on the difference in temperature. Heat transfer does, yes. But radition is an intrinsic quality of the radiating body, and is not dependent on the surroundings. It is however dependent on the energy content of the body, the warmer it gets the more thermal radiation it will emit.

A human body at 37 degrees should according to Aluminium broadcast a thermal radiation in the region of 500 W/m2. Are you saying that we would not feel that if we stood next to them? Of course we would! And how much energy would they be losing through all this radiation?

Standing next to a lump of ice, a person would radiate enough energy to melt several centimeters of that ice. Well, le'ts make some calculations: If a standard westerner were to stand naked next to a 2 m2 lump of ice, and melt 5 cm off the surface, or 100000 cm3, i.e. 100 kg. The latent heat of ice at 333 kJ/kg equates this to 33.300 kJ or almost 8000 Calories.

If Aluminium's numbers were correct, we would each of us be losing energy at a rate of some 15.000 Calories per day. So bring on the beer and the strawberries in cream!

Consider also: if thermal radiation was anywhere near as important a method of heat transfer as conduction or convection at "weather" temperatures, then insulation would not work. Wearing clothes would not keep you warm. Insulating your house would not keep you warm. Using double or triple layered glass would not be worth the effort. The whole idea of insulation is to stop or retard convection and conduction, but most of the time it does not take thermal radiation into account at all. And yet it works surprisingly well!

3
Arctic sea ice / Re: Arctic energy balance
« on: Today at 11:41:52 AM »
Do you feel atmospheric pressure? I don't. But this pressure is 1 kg/cm2!

Effect of insolation is strongly reduced by high albedo and atmosphere. But thermal radiation from the ice is not and should be exceeded somehow for any melting.

Those numbers are about radiation from surface of body or border of atmospheric layer.

I am still absolutely convinced that thermal radiation is negligible when it comes to transfer of heat from a body of air to the surface (e.g. ice). Conduction is how things happen in the real world, with the huge exception of the sun of course.

As for your pressure comparison, it falls at the first hurdle: We would very certainly feel if the pressure went away. We do not feel any difference from being in the vicinity of a 15 degree or 0 degree or 30 degree black body - or not. Do you feel radiative heat from other people? Try walking up to a person and away again - could you feel the difference in thermal radiation from a 37 degree C "black or otherwise coloured or not" body?

The only thermal radiation we are likely to feel (both when it appears and when it disappears) is from the sun, from fire, and from objects significantly warmer than atmospheric temperatures.

Thermal radiative heat transfer from air is negligible no matter what numbers you band around, neither of us has the abillty to work this out mathematically, specifically: How much thermal radiation is received by the surface from a 15 degree C airmass passing overhead. My contention is that it is exceedingly small (otherwise the entire airmass would be cooling rapidly).

All experience and common sense says that it is negligible, and claiming that the thermal radiative transfer from a 15 degree airmass passing overhead is in the same as the heat of the sun in the tropics is ridiculous.

I've had quite a lot of experience in standing under a 15 degree C airmass in deeply overcast weather and it does not feel warm. Where I am now, if I stick my head outside at this very moment (12:38) I recieve a full 400 W/m2 tropical insolation. And I can very well tell you that it feels extremely much hotter!

4
Arctic sea ice / Re: Arctic energy balance
« on: Today at 10:05:41 AM »
Thermal radiation from a 15°C black body is 391 W/m2. Thermal radiation from a 0°C black body is 315 W/m2. Difference is 76 W/m2 or 2 cm/day of ice.

I am unable to make sense of this. Are you saying that 76 W/m2 melts 2cm/day of ice? And how can you say that a black "body" has a thermal radiation of X W/m2. What size? What mass? How long does it last?

Thermal radiation at 400 W/m2 is the average insolation in the Tropics! Does this sound likely? That standing next to a 15 degree C blackbody would warm you as much as lying out in the sun on the Equator? Does this sound likely.

Solar insolation at peak in the Artctic reaches 500 W/m2 and would melt 13.5 cm/day according to those numbers, or around 1300 km3 per day. Does that sound reasonable?

A nonsensical hypothethical: If a warm body of air at 15 degrees is able to lose all of it's energy through thermal radiation in one day, then the atmosphere would be quickly plummeting towards 0 degrees K.

Even if we substitute "all" with "a significant amount" then we would still be hurtling towards a mega ice-age.

Air at 15 degrees may be radiating heat in all directions, and "black body" radiation may be significant, but I suspect that most of that radiation is caught internally by the air itself. The effect of this thermal radiation on the surface is going to be exceedingly small.


5
Arctic sea ice / Re: "Stupid" Questions :o
« on: Today at 09:21:20 AM »
Binntho, I thought I made it clear that your snark was in the wrong, and yet you continue with more interpesonal mayhem. Maybe you dislike arrogance, you are certainly arrogant yourself as I am sure you are aware, I can be arrogant too, but that is not the point of this thread. The point is to answer stupid and not stupid questions helpfully, or not answer. If you dislike something, just take a deep breath and don't answer.
I have been lax, more unhelpful posts will be snipped.
Heard and understood!

6
Arctic sea ice / Re: "Stupid" Questions :o
« on: Today at 08:51:05 AM »
But ignorant arrogance tends to stroke it the wrong way.

The thread title strongly implies that there is no question too stupid to be asked here.

Literally!

Indeed! Absolutely!

Ignorant arrogance or arrogant ignorance is still not a good combination if you expect questions to be answered.

7
Arctic sea ice / Re: "Stupid" Questions :o
« on: Today at 07:19:51 AM »
Thanks igs for your reminder that ignorance is a shared characteristic, one we all suffer from!

Differently in different areas, of course. And if you've taken courses and read books with names like "How to fake expertise" and "How to write meaningless drivel" and then think that you can apply the methods learned in a forum of people who, while ignorant, are not stupid, does tend to diminish ones rights to polite and considerate treatment.

8
Arctic sea ice / Re: Arctic energy balance
« on: Today at 07:13:09 AM »
Tables are convenient. One last thing is wind front. 5 m = 0.005 km. And we have 0.1% in result.

10-14 kg/m2 of water vapor is a high number for the Arctic. May begins with below 5 kg/m3 usually.

Considering thicker layer, strong WAA contains enough energy to melt 200 km3/day. It does not mean that only the WAA did 200 km3 per day. But there is a way to transfer significant part of this energy to make the ice darker and more vulnerable for visible light. Combined effect of the WAA and clear sky seems to explain extreme melting that day.

Having said that, I am pretty sure that radiative thermal transfer of air only starts to become significant in comparison to conduction at much higher temperatures than are found in the atmosphere.
looking at the main image here, conduction is actually negligible compared to radiation.

I can see that you found the error that I feared in my dreams!

The only real contention in all of this is the thickness of the air used in the calculation, and that in the end rests on the relative effects of conduction vs. radiation.

At "weather" temperatures, radiation is truly a wimp when it comes to transferring heat. You can test this on your self - you do not feel heat radiating from a window even if it's freezing inside and 20 degrees outside. But you feel the temperature of the air as soon as you touch it.

You do not feel the heat of thermal radiation from a hot tub of water - but you do feel the heat of the steam settling on your skin. You do start to feel the heat of radiation from the sides of a freshly boiled kettle, but still not enough for you to stop touching it by mistake and then fealing the real heat transfer of conduction.

So if you think that thermal radiation from a 15 degree C body of air in one day is enough to melt any ice at all, let alone any significant amount, then please show some evidence!

9
Arctic sea ice / Re: Arctic energy balance
« on: Today at 07:06:16 AM »
@bintho : in the above calculations, I believe I miss the energy of condensation of the water vapour in the air mass. The air is likely to reach dew point on the ice I think?

You are absolutely right, I am aware of this missing factor and I'm not at all sure how to estimate it. Phoenix had a link to a paper on another big warming event in early August 2014 where they claimed that the air was very "moist" (I think they meant "humid") and that the water vapour condensed into a dense fog which then increased the effects of insolation significantly. Which is interesting, since one of the perennial questions on this forum is ast to what effects the often observered fog can have on the ice.

Not knowing the humidity of the air is a problem, but if we assume 50% humidity (probably way too high, but never mind) at 15 degrees C then that translates into 5 g vapour per kg (or m3) of air. Total amount of water vapour in 36 km3 can then be calculated as 180.000 tons of water. The latent heat of water vapour is 2,260 kJ/kg, so the total latent heat of 180.000 tons is 4E12 kJ. Which is truly a massive amount of energy!

This is not surprising, everybody who has ever seen the different melting rates from a relatively humid wind as opposed to a dry wind would not be surprised.

But even if we were to add this number to my previous calculations, it would only change the final conclusion by a factor of 10, i.e. increasing the percentage contribution of the WAA on 10th June 2019 to the melt of 200km3 to a number that is still less than 1%.

10
Arctic sea ice / Re: Arctic energy balance
« on: Today at 06:49:10 AM »
Having spent a fitful night tossing and turning (blackout, thunderstorms, mosquitos etc.) I couldn't help but feel that I had mad several major mistakes in my calculations. Being too busy to go through them again this morning, I'd like to state here and now that I wouldn't be surprised if I was off by a factor of 100 in the final numbers, although even that would not change the basic conclusion.

11
Arctic sea ice / Re: Arctic energy balance
« on: June 02, 2020, 05:26:19 PM »
To begin with, there was an error in the units, it should have been 2E16 kJ which adds 3 zeroes to the calculation.
3600 km3 * 5kJ/m3 = 2E13 kJ = 2E16 J = 0.03% * 6E19 J. I am still sure this is correct result in your calculations. Though I doubt in assumptions.

I am unable to change my original posting to correct the "Chukchi" for "Laptev" and "J" for "kJ". But I have been through my calculations again and found several errors. The final conclusion is however still valid.

Let's start with the ice:


Latent heat is the amount of energy needed to melt ice at melting point. Of course, more energy is needed in the real world, since any large scale melt event will also have to heat up a significant amount of ice.

The calculations were made in response to Phoenix' claim that one day's WAA had melted 200km3 of ice, hence the last line. Which by the way is off from my previous calculations by a factor of 1000!  :( :( :(

So for the air:


Specific heat is the amount of energy released when temperature goes down by 1 degree C (actually defined the other way around, the amount of energy needed to heat by 1 degree C).

As has been pointed out, humidity does not alter the result in any significant way. Air at 15 C and 100% humidity is only 1% water (or 10 g/kg), so if the air had been at 100% humidity (which is a wild overestimate), the final number would still go up by only 1%.

So finally for the air mass on that fateful day, the 10th of June 2019. I am assuming a temperature of 15 degrees, and the thicness of the layer of air able to conduct energy to the surface at a generous 5 meters. Wind speed is around 15km/hour as the air leaves the coast according to Nullschool.



So here I have the second major mistake found in my earlier calculations when I assumed 3600 km3 of air, while the actual number is 36.

I end with exactly the same percentage as in this post which was calculated in a different way, which increases my confidence in the result being correct.

Secondly, Nullschool shows very little precipitable water in the air coming from Siberia at the time.

Thirdly, even if water vapor has two times the heat capacity of air, the total amount of water wapor that air can hold is very low, and at arctic temperatures, it is well below 1%. Even at tropical temperature levels, 100% humidity translates into about 4% water by weight of the air column.
Specific heat of vaporization is 2.3 MJ/kg. Given this, water vapor can transfer more energy than dry air.

I have never disputed that water vapour can carry more than double the amount of energy as dry air. But the point that I seem to be making all the time is that even at the maximum possible humidity of 100%, only 1% of the airmass is water vapour. So it effectively makes no difference.

So was this a dry or a humid event? We have both referenced Nullschool showing "Total Precipitable Water". How that relates to humidity I have no idea. Given that the Worldview images of EES and Laptev was clear as can be on that day (the 10th of June 2019), I doubt that there was much if any condensed water in the air, so the appellation "moist" seems most misguided.

Nullschool puts most of the wind coming in over EES at 10-14 kg/m2 total precipitable water, but over the Laptev up to 20 kg/m2. As I have no idea what means in the real world, I compared with some dry places on the planet, and found that the Sahara desert fitted the bill pretty well, ranging from 5 to 18 kg/m2. So I would tend to assume that this was an extremely dry event, dry as a desert.


Radiative transfer is most likely negligible in this scenario
It sounds like solar radiation is negligible for the ice. Seriously, both have similar power but visible light is mostly reflected and longwave infrared is mostly absorbed. Back radiation strongly (T4) depends on air temperature.

Well, I certainly did not mean to say that solar radiation was negligible.

But I did intend to say that a warm airmass will release its heat by conduction primarily, with radiative heat loss being very small and in effect negligible. This is however outside my knowledge of physics, so I am not able to give any calculations.

Having said that, I am pretty sure that radiative thermal transfer of air only starts to become significant in comparison to conduction at much higher temperatures than are found in the atmosphere.

12
Arctic sea ice / Re: Arctic energy balance
« on: June 02, 2020, 03:47:13 PM »
Do you not understand that heat is thermal radiation?

No, heat is not thermal radiation. Your question shows a lack of undersanding of thermodynamics. But I must admit that I have been using the word "heat" with lack of precision.

So let us split it into more formal categories / definitions:

1) Heat transfer is the transfer of energy from one system to another. There are basically two methods of transferring thermal energy, radiative transfer and conduction (some Americans add friction as a method of transferring heat, but that's of no consequence).

Radiative transfer of energy is how the sun warms the earth (and our skin when we are out in the sun). Conduction is how air (and water) primarily transfer heat internally and to other bodies, although some radiative transfer is always ongoing (and grows with added energy, but it needs well above "weather" temperatures before radiative heat transfer overcomes conductive heat transfer).

Heat transfer is sometines referred to with the single word "heat" only. So in that sense, thermal radiation is "heat" but not the other way around, since conduction is another form of heat transfer, and the use of "heat" can mean more than heat transfer.

2) The energy contained in a system, and which we measure by e.g. sticking a thermometer into it (which by the way works by conduction) is also called "heat". As in if air is at this and this temperature then it contains so and so amount of heat.

Strictly speaking we should use the word "energy" here, and in all my calculations when I use kJ
 (kilo Joules) for latent heat or specific heat and the melting potentiality of air at this or that temperature, it is in fact "energy" we are talking about.

3) In my calculations I have shown that the Warm Air Advection contains nowhere near enough "heat" (meaning energy) to have any significant effect on melting. The paper that you have linked does not claim that the energy carried by the WAA has done any melting. So the paper does not disagree with my calculations.

4) The paper claims that the WAA created circumstances whereby the efficiency of the thermal radiation from the sun was kicked into overdrive. That may or may not be true, I have no idea, but I do question the use of "moist" air when Nullschool shows dry air, comparable to the Sahara at the same time. Perhaps they are right, and the air was "moist" (although where did the moisture come from?), or perhaps Nullschool has it wrong, or perhaps I am misunderstanding Nullschool. Makes no real difference to this discussion.


13
Arctic sea ice / Re: The 2020 melting season
« on: June 02, 2020, 03:19:21 PM »
The record breaking NSIDC sea ice area gains continue. This is the third record breaking daily increase in the last 8 days (5.25,5.31, and 6.1).
Could you please indicate if this is an artifact or if the ice is really freezing exceptionally fast at this moment? The latter seems very unlikely, given the current temperatures in the Arctic.

14
Arctic sea ice / Re: "Stupid" Questions :o
« on: June 02, 2020, 03:17:56 PM »
Feel free to ask any relevant question, especially if you are a newbie or rarely post, with no repercussions or snark. If you are an experienced poster google should certainly be your friend as you turn to this thread, but it's not a must. If people don't care to answer, they can simply skip the question.
In any case binntho's implied snark is in the wrong, though his response may be useful in finding the answer.

Snarkily implied at that! Usually I enjoy googling for people and distilling what I read and then telling them what conclusions I've come to. It's the educator in me that likes to be stroked every now and then. But ignorant arrogance tends to stroke it the wrong way.

15
Arctic sea ice / Re: The Arctic for Amateurs and Newbies
« on: June 02, 2020, 02:56:14 PM »
Freegrass, I assume that you are aware of the fact that the Western seaboard of Europe and N.America is much warmer than it should be given their latitude. The standard explanation is that the warm North Atlantic Current and the North Pacific Current respectively keep the Western margins of the continents warmer.

In my understanding, the mechanism by which this happens is by primarily by heat transfer via low pressure areas (storms).

I agree with your assumption that the low pressure areas and storms that form in warmer latitudes will lose their heat when they travel north over colder waters. When they travel over warm currents, the low pressure areas lose less heat than when they travel over "normal" waters. Since due to the coreolis effect, the storm tracks and the currents tend to follow the same east-by-north tracjectory, the two of them together cooperate in transferring southern heat to the northern latitudes.

Basically, when a storm enters the Arctic from the south, it has been prevented from loosing all it's heat by the comparatively warm surface waters of the North Atlantic.

Besides maintining a high temperature due to the warm ocean currents, the stormy winds carry a lot of water in the form of droplets, and their heat capaicity is significantly higher than that of the wind itself. The stronger the storm (effectively, the warmer the ocean area where it was formed), the more precipitable water it will carry. And that makes a very big difference to the ice, making rainy storms from the North Atlantic very efficient carriers of heat into the Arctic.

THe kinetic effect of a storm will be stronger in the latter half of the melting season, when there is more open water, but will never be negligible. But I doubt if the kinetic effect matches the heat effect of a storm at any time, although I may well be wrong.

16
Arctic sea ice / Re: Arctic energy balance
« on: June 02, 2020, 07:48:25 AM »
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015GL064373

Geophysical Research Letters
Warm‐air advection, air mass transformation and fog causes rapid ice melt
June 2015

Abstract
Direct observations during intense warm‐air advection over the East Siberian Sea reveal a period of rapid sea‐ice melt. A semistationary, high‐pressure system north of the Bering Strait forced northward advection of warm, moist air from the continent. Air‐mass transformation over melting sea ice formed a strong, surface‐based temperature inversion in which dense fog formed. This induced a positive net longwave radiation at the surface while reducing net solar radiation only marginally; the inversion also resulted in downward turbulent heat flux. The sum of these processes enhanced the surface energy flux by an average of ~15 W m−2 for a week. Satellite images before and after the episode show sea‐ice concentrations decreasing from > 90% to ~50% over a large area affected by the air‐mass transformation. We argue that this rapid melt was triggered by the increased heat flux from the atmosphere due to the warm‐air advection.

(from conclusion - An extra 20 W m−2 surface heating would theoretically melt an additional ~4–5 cm of ice over 7 days)


Interesting article, but the melt is caused by changes in radiation, not the heat of the WAA.

In my original post, the cloudiness of the entire Arctic except for the EES and Chukchi caused me to wonder what the net radiative effect was,  i.e what type of clouds they were. Also given that the Arctic was governed by a high-pressure system at the time, I would have expected clear skies and not the clouds that were actually visible.

So this paper is saying that the clouds were in fact lowlying fog that enhanced melt significantly. Both assumptions are interesting, the fog being the result of the "humid" air from Siberia, and that fog over ice increases rates of melting.

Going back to Nullschool, the "humidity" of this event was very low, similar to that found over the Sahara at the same time. So where do they get their "moist air" from? Or is Nullschool so totally wrong?

Finally, if 5cm of ice melts over the entire arctic over the 7 day period, that translates into 500 km3, while the actual melt at the same time was around 1500 km3. So this "massive" event could concievably count for 1/3 of the melt at the time.

17
Arctic sea ice / Re: Arctic energy balance
« on: June 02, 2020, 07:33:03 AM »
The thickness of the air is of course debatable, I used 5 m as a guess, but even if we were include all 10km of the troposhere, the difference is still only 2000 fold, going from 0,00003% to 0,06% of the energy needed to melt 200 km3, totally unrealistic presumption but not getting us anywhere near a real effect.
2E16 J is 0.03%. 1 km thick layer has 200 times more heat capacity and was at least 3 times warmer. This event was not dry. Water vapor contains approximately 2 times more energy. Result rises to 2E19 J or 30%. Thicker layer contains even more energy and wind speed was higher.

I made some calculations before with the same order of magnitude in result.

To begin with, there was an error in the units, it should have been 2E16 kJ which adds 3 zeroes to the calculation. So the calculation is correct, the units were in error. I'll hurry and correct the original post!

Secondly, Nullschool shows very little precipitable water in the air coming from Siberia at the time.

Thirdly, even if water vapor has two times the heat capacity of air, the total amount of water wapor that air can hold is very low, and at arctic temperatures, it is well below 1%. Even at tropical temperature levels, 100% humidity translates into about 4% water by weight of the air column.

It took me a few seconds to find on the omniscient Internet that at 5 degrees, the maximum carrying capacity of air is less than 0,07 kg/m3, so 0,7% per weight.

Water vapour makes practically no difference inn our case - 99% * 1 + 1% * 2 = 1,01.

I don't know why you think that we should count a full 1km in this case. The air that touches the surface is the air that transfers heat to the ice. Radiative transfer is most likely negligible in this scenario, so again - given som turbulence at the surface I think that counting the bottom 5 meters is of the correct order of things.

Finally, Nullschool for the day shows that air temps leaving the Siberian shore at around 15 degress C. I used the temperatures over the EES as a basis for my calculation, and estimated that 5 degrees C were available to be used for melt. I'll admit that the 15 degrees is better, raising the final number to:

Only 0,001% of the energy needed to melt 200km3 of ice was supplied by the WAA.

18
Arctic sea ice / Re: "Stupid" Questions :o
« on: June 02, 2020, 07:18:05 AM »
I have a question and an observation for board comment.

Put "penetration depth of solar radiation into the ocean" into google and read the answers.

19
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: June 02, 2020, 07:12:53 AM »

Another significant increase in the daily northern hemisphere NSIDC sea ice area value. 2020 now has more sea ice area than 2019 for the date.



This looks very suspicious to me, that black line taking off like that. I would assume that this was an errror in the data unless proven otherwise.

20
Arctic sea ice / Re: The 2020 melting season
« on: June 02, 2020, 07:10:16 AM »
In June aren't clear skies and forecast warmth just as good as stormy weather to melt out ice?
The sun adds heat to the system. Storms take it away. Because all storms do is they stir up the water, bringing heat to the surface that melts the ice, and vanishes into the atmosphere. Storms add nothing to the energy balance, right?

A storm brings a hell of a lot of warm and wet air from further south. Low-pressure areas form mostly over the N-Atlantic, sometimes as far south as the Gulf region, and flow northwards. They carry massive heat and moisture besides all the kinetic energy that churns the ice up.

Sunny skies vs. strong storm is one of the perennial debates on this forum, opinion seems to me to be that the ice can melt just as easily when battered by a strong storm as it can under direct insolation. But perhaps timing is important here also - a storm at the time of maximum insolation in June an July may cause less melt than clear skies, but later in the season I would guess that a good storm can do much more damage than the sun. Besides, the kinetic factor is probably most effective late in the season when there is more open water to whip up into waves, and easier to push the ice around.

21
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: May 31, 2020, 06:35:20 AM »
Phoenix, I tend to consider the method of argumentation that is based on just publishing links and extracts from research papers found on the internet as not very effective, basically just the nerdy version of arguing with youtube clips. The papers (and youtube clips) may contain oceans of truth and unfathomable depths of wisdom, but if you can't say yourself what you think they are saying, then I won't bother trying to find that out for you.

22
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: May 31, 2020, 06:31:09 AM »
In short, WAA can melt snow, reducing its albedo and letting in the real monster, sunlight. So you cannot completely discount it no matter what calculations show regarding total energy transferred.

Absolutely. As can many other things. The fallacy inherent in this WAA discussion is that continental mainland is somehow more effecient at transferring heat to the Arctic than the open ocean.

Nobody is disputing that continental heat waves can transfer heat to the Arctic, my contention is that this is an effect that is mostly negligible except for the short window of time where Siberian or Alaskan WAA kan cause rapid near-shore melt.

And my calculations seem to show that it is propably not the heat transferred by the  WAA that is the main cause of near-shore melt (the effect is truly small), but most likely the clear skies that follow those situations where WAA is stronges, allowing for much more insolation, and yes, helping that insolation along by wetting the surface.

Once the near-shore ice is gone, the vast heat transfer ability and energy distrubing potential of open ocean kicks in. Clear skies over the EES, Laptev and Chukchi are probably much more important here than any occasional WAA.

The Arctic happens to be near surrounded by continental land masses. Any warm air advection from the south is going to cause melt. But the net effects of the continents is to retard melt and increase ice formation, while the net effect of open ocean is to accelerate melt and decrease ice formation.

Just consider snow cover on the mainland - open ocean has no snow cover. So warmth from the south has to battle accross the accumulated snow on the mainland before it can begin to have any effect on the Arctic. This is obviously not the case where the ice is bordered by open ocean all year round!

23
Arctic sea ice / Re: Arctic energy balance
« on: May 31, 2020, 06:15:21 AM »
a. Latent heat of ice 333 kJ/kg, specific weight of ice 919 kg/m3, 333 * 919 = 306.027 kJ/m3

Roundly speaking, 3E8 kJ/m3 * 200 km3* 1.000.000.000  m3/km3=6E19 kJ needed to melt 200km3 of ice, 60 billion billion.

b. Windspeed at the time was around 15 km/hour and the Siberian front (EES and Chukchi) is some 2000 km. Ef we generously count the lowest 5 meters of air (assuming some turbulance), we are looking at perhaps 3600 km3 of air in 24 hours.

c Specific heat of air is 1kJ/kg, specific weight 1,3 kg/m3, so specific heat per volume = 0,8 kJ/m3. Temperatures in the EES at the time were around 3 degrees Centigrade, so if we assume that the air loses 5 degrees of heat solely into the melting of ice, the daily volume of air from Siberia would supply 3600 * 1.000.000.000 * 5 kJ = sligtly less than 2E13 J.

d) 200km3 of ice needs 6E19 J to melt, warm air from Siberia supplies 2E13 or 0,00003% of the energy needed.

a. 6E19 J or 6E16 kJ is in result.

b. I think, thicker layer should be considered. Back radiation is comparable with solar globally and more effective to warm up snow or ice.

c. 2E13 kJ or 2E16 J is in result.

d. Very thin layer without water vapor was considered. Yes, It's negligible.

Thanks for pointing out the discrepancies in units. It should have read kJ all the way down. Furthermore I can see that where I say "Chukchi" it should read "Laptev".

The result is so vastly less than anything that could be accounted as likely - i.e. there is no way that the heat wave in Siberia on 10th June 2019 could have melted 200km3 of ice that day, as Phoenix claimed (not suggested, but a straight faced claim).

I am aware that no water vapor was included in my calculation. Nullschool shows that the air was very dry on that day, and anyway the difference in heat capacity of air at varous levels of humidity seems to make hardly any real difference. The specific heat of water wapor is 1.82 kJ/kg compared to ~1 kJ/kg for air. At 5 degrees C and 50% humidity, the proportion of water wapour to air is still very low, less than 1% so making hardly any difference, well within the error margin of ~1 kJ/kg.

The thickness of the air is of course debatable, I used 5 m as a guess, but even if we were include all 10km of the troposhere, the difference is still only 2000 fold, going from 0,00003% to 0,06% of the energy needed to melt 200 km3, totally unrealistic presumption but not getting us anywhere near a real effect.

Also if we raise the temperature, even to the max of 32 degrees, the highest that has ever been recorded within the Arctic circle, the difference is still only 6 fold.

The heatwave in Siberia and the very impressive looking WAA from Siberia in over the EES and  Laptev on 10th of June 2019 had the potential to melt 0,006 km3 of ice. THe EES and Laptev together are around 1.6 million km2, implying a melt of 4mm on that day if all the melt happened in those to seas. Which is not negleglible but nowhere near enough to have any real impact in the Arctic as a whole.

So my conclusion seems to stand: WAA from the continents does not have anywyhere near the capacity to cause any significant melt in the Arctic.

24
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: May 30, 2020, 01:04:42 PM »
I am trying to demonstrate that WAA is important because several others have questioned its importance. In the process of exploring that, I've learned a bit from users like Aluminum. 

If you are unable to point out any flaws in my post Arctic energy balance then you will have to give up this WAA hypothesis.

According to my calculations, the amount of heat that can possibly be advected via WAA is so miniscule that it cannot be used to explain anything. This is mostly because of the vast imbalance between the specific heat of air and the latent heat of ice - any amount of warm air that can be advected from Siberia can only melt a miniscule amount of ice.

Unless my math is totally wrong. So please try and work it out for your self. Or accept that your hypothesis is dead in the water.

25
Arctic sea ice / Re: Arctic energy balance
« on: May 30, 2020, 09:51:46 AM »
I think, 7...8 km upward is harder way for photons than 0...1 km downward.

There was strong one in mid-June 2019.



This chart shows a increase in daily melt rate of 200 km3 in response to a well documented Siberian heat wave. Is there any reasonable alternative explanation for the rapid melt increase other than WAA from Siberia ?

How do you know it was in response to a heatwave in Siberia? And have you looked at other explanations? Coincidence is not causation.

Looking at Nullschool and Worldview for the same dates shows winds from Siberia and high air temps over ESS and Chukchi. But also very clear skies over ESS and Chuckhi. The Arctic itself was under a minor low pressure area, but the air seems to have been very dry at the time which may have led to cloud levels that lets a fair bit of solar energy through, and isolates against outgoing infrared radiation as well. I don't know if that was the case, the clouds, as usual, are a wildcard.
 
1. Hypthetical explanation: clear skies and/or high cloud during maximum insolation coincides with a Siberian heatwave and may well share some of the causes, i.e. slow-moving winds and clear skies.

2. Hypothetical explanation: The very real  warm air advection from Siberia clears away the ice  in the ESS and Chukchi (which wouldn't have been there in the first place if it wasn't for being sheltered all winter by Siberia). The appearance of open water under clear skies and massive insolation excelerates melt.

But the biggest problem with your claims Phoenix is that the amount of heat that can concievably be carried by air from Siberia in over the Arctic is far too small to be able to cause the observed melt.

a. Latent heat of ice 333 kJ/kg, specific weight of ice 919 kg/m3, 333 * 919 = 306.027 kJ/m3

Roundly speaking, 3E8 kJ/m3 * 200 km3* 1.000.000.000  m3/km3=6E19 kJ needed to melt 200km3 of ice, 60 billion billion.

b. Windspeed at the time was around 15 km/hour and the Siberian front (EES and Chukchi) is some 2000 km. Ef we generously count the lowest 5 meters of air (assuming some turbulance), we are looking at perhaps 3600 km3 of air in 24 hours.

c Specific heat of air is 1kJ/kg, specific weight 1,3 kg/m3, so specific heat per volume = 0,8 kJ/m3. Temperatures in the EES at the time were around 3 degrees Centigrade, so if we assume that the air loses 5 degrees of heat solely into the melting of ice, the daily volume of air from Siberia would supply 3600 * 1.000.000.000 * 5 kJ = sligtly less than 2E13 J.

d) 200km3 of ice needs 6E19 J to melt, warm air from Siberia supplies 2E13 or 0,00003% of the energy needed.

Of course my calculations could be wildly off, I've been through them a couple of times and I am honestly very surprised to see how little effect the WAA from Siberia has directly according to these calculations. So perhpas somebody could check them.

Phoenix, you should as a minimum be able to do these calculations yourself before making claims such as those above.

26
Arctic sea ice / Re: The 2020 melting season
« on: May 27, 2020, 01:31:54 PM »
Snow and ice around the Polarstern, north of Svalbard, yesterday. 360deg image viewer here
Bare ice is visible at centre. click for full resolution.
Very interesting. From experience, I would say that the shiny white is wet snow, perhaps very thin and probably fresh (i.e. sleet or wet snowfall within the last few days?)

Blue colouring is visilbe around the leads, this I would see as reflection of daylight inside wet snow, i.e. we are seeing edges of perhaps thicker snow where the leads are opening up. Part of it could be reflection of the water in the lead.

The steel-gray areas look like typical ice with a melting and slightly wet surface.

Nothing resembling proper melt ponds (the blue colorings are not meltponds in my opinion although at first it may look like it).

The above is based on experience with snow, ice and glaciers but since the age of 4 I have not seen proper actual arctic sea ice myself (and I can't say that I really remember it). Somebody actually on the Polarstern could perhaps give a commentary of what we are seeing?

27
Arctic sea ice / Re: The 2020 melting season
« on: May 27, 2020, 12:58:57 PM »
Perhaps a bit more effort at content and even calculation, end slightly less emphasis on the condescension.

28
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: May 26, 2020, 01:50:49 PM »

Rather than argue, I'll ask a few question.

Let's construct an example. There is a land based heat wave in Siberia near the Laptev Sea with 25C temps over land. The GFS weather map indicates a plume of heat into the Laptev with color coded gradations representing heat in degrees C. Immediately adjacent to the coast is a semicircle which extends 100 km into the Arctic at a temperature of 3C. A bigger area extends beyond to 300 km from the coast at a temp of 2C and a 1C plume extends out to 800 km from the coast.

How do you interpret that?

I see that the sun has warmed the earth and that the warm air from the earth is traveling out over the coast and dissipating as it gets farther away from the coast. Do you see the same thing?

So you give me an imaginary anectdote and want me to say something other than the obvious? Of course there is warm air advection from Siberia to the Arctic at times, and sometimes quite significant, although of course, this is only air moving about, with very low heat capacity, and the reason it gets so hot is that it's not really moving very much in the first place. Because, you see, the sun doesn't shine any harder on continents than other ents.

Heat transfer from the continents is real but is very unlikely to rank higher than at best third place after direct insolation on the ice in first place, and ocean heat absorbtion and transfer (and increasingly, wave action) in strong second place when accounting for ice melt during summer. My own guess would be that third place is taken by low-pressure areas bringing kinetic energy from the southern oceans, stirring up heat from below and bashing the floes together.

The oceans have much higher heat capacity, are much more easy to move around than the continents, and have much lower albedo. So the oceans are the clear winners by far when it comes to collect, store and transfer the heat energy from the sun from anywhere to anywhere when compared to warm air over contintents.

And of course, the flip side of the continental hot summers are the very long and very cold continental winters. Were the Arctic not sheltered in the cold embrace of those massive continents, it would grow much more slowly in winter and disappear easily every summer.

29
Arctic sea ice / Re: DHACSOO - A Durable Arctic Hypothesis
« on: May 26, 2020, 06:22:48 AM »
I agree, this is a better forum for these discussions.

On the other side of the screen you see a blast of warmth coming in from the Atlantic over Svalbard. That's coming from a long way away and it isn't getting any local land based boost. It's either coming from Scandinavia or the Atlantic (not sure which or both) with a lot of atmospheric assistance from a massive high pressure system that extends all the way from the mid-Atlantic to the Kara Sea and a low off the coast of Greenland.

The Arctic ocean, being as it is sheltered by landmasses on most sides, mostly misses out on this massive advection of heat from the southern oceans. The only real front open to the oceans is the Atlantic, with the shallow Barents sea and the Svalbard / Franz Josef Land barrier stopping the warm currents from properly entering the Arctic.


In the interest of keeping this thread on topic, I reply here if you want to continue.

https://forum.arctic-sea-ice.net/index.php?topic=3097.msg265708#msg265708

Regarding the concept that a land barrier is an impediment to Atlantic water entering the Arctic, I diagree. The Spitsbergen Current brings enough warm Atlantic water to the Arctic to melt all the ice many times over. The defense mechanism against the Atlantic water is the less dense fresh water lens at the surface. Uniquorn might be a good person to comment on this.

https://oceancurrents.rsmas.miami.edu/atlantic/spitsbergen.html

The reason why I wrote the above comment was your seeming ignorance of the possible origins of warm air entering the Arctic from the Atlantic. Which implies a lot of ignorance regarding ocean currents and how they move heat around the globe.

As for the land barrier, it is both the barrier and the changes in bathymetry that follow the same line that prevent the warm Atlantic currents from free entry into the Arctic. At the same time, the land barrier protects the inner Arctic from the massive storm generated swells that are common in the North Atlantic, and from storm waves in general, and waves are well known to not only break up the ice but to mix up the underlying layers.

Which is why I willl continue to point out that without the cold embrace of the surrounding continents, the Arctic would be ice free in summer every summer.

That the land protects the ice, while access to open ocean hinders the ice, becomes obvious when you compare the two sides, Atlantic and Pacific. The typical line of extent on the Atlantic side is where the Atlantic warm waters are forced to sink and / or deflect due to land and bathymetry. On the Pacific side, it is the landmass that is the delimiter. If the coast of Siberia or Canada were to move a 1000 km further south, the ice would follow, just as it forms every winter on the Hudson as far south as the latitude of London- another body of water in a continental cold embrace.

Continental summer heat does not travel well, and is therefore not a good source of the heat that melts the ice in summer. Ocean heat travels extremely well. But of course, by far the biggest melt effect in summer stems from insolation.

Heat from continents is probably a distant third after insolation and heat transfer from the Atlantic and to a lesser extent the Pacific.

30
Arctic sea ice / Re: The 2020 melting season
« on: May 26, 2020, 03:44:58 AM »
On the other side of the screen you see a blast of warmth coming in from the Atlantic over Svalbard. That's coming from a long way away and it isn't getting any local land based boost. It's either coming from Scandinavia or the Atlantic (not sure which or both) with a lot of atmospheric assistance from a massive high pressure system that extends all the way from the mid-Atlantic to the Kara Sea and a low off the coast of Greenland.

You may not be aware of the massive heat conveyor belt called the North Atlantic Current, and further south commonly referred to as the Gulf Stream. The oceans carry vast amounts of heat from mid latitudes northwards, both in the Pacific and the Atlantic, and the heat that makes the North Atlantic such a relatively balmy place has it's orgins mostly on the Caribbean and the Gulf of Mexico.

Over the ocean conveyor you wil often find a low-pressure conveyor, where one low pressure area after another is carried northwards, essentially being the mechanism by which the high temperatures of the ocean surface is spread outwards to warm the British Isles, Scandinavia, Iceland and Svalbard to temperatures that are far above what is found elsewhere at the same latitudes.

In the Pacific, the North Pacific drift carries heat from mid-latitudes north and east towards the Canadian Pacific coast and southern Alaska, again making those areas much warmer than they otherwise would have been. The warming effects of the oceans can be seen by comparing average temperatures on the western and eastern boundaries of the northern reaches of each ocean. The warm currents hug the eastern boundaries due to the Coriolis effect, keeping them considerably warmer.

The Arctic ocean, being as it is sheltered by landmasses on most sides, mostly misses out on this massive advection of heat from the southern oceans. The only real front open to the oceans is the Atlantic, with the shallow Barents sea and the Svalbard / Franz Josef Land barrier stopping the warm currents from properly entering the Arctic.

If the Arctic was not so sheltered behind the massive landmasses of Asia and N.America with their cooling effect, we would probably see BOE every year.

31
Arctic sea ice / Re: What's new in the Arctic ?
« on: May 25, 2020, 01:04:14 PM »
Those pesky rodents get everywhere! Interesting article on glacier mice.

32
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: May 23, 2020, 06:11:54 PM »
Note that the melting of massive amounts of Greenland's ice in 2010 and 2012 may have led to a strong cooling of the north Atlantic southeast of Greenland. This cooling may have reduced the amount of ocean heat transported into the Arctic through the Fram strait.

The slow down in sea ice extent loss since 2012 is likely related to the cooling in the far north Atlantic caused by the influx of cold fresh melt water.

This seems to me to be pure conjecture, and as for the "slow down", well that has been repeatedly discussed and I for one have not seen any convincing evidence of there being anything other than an ongoing linear reduction in sea ice with random annual fluctuations. Choosing the record year as the starting point of a hypothetical slow down tastes surprisingly like cherry picking.

The annual melt of the Greenland glacier goes mostly to the west, not the east, and is caught by the West Greenland current moving counter-clockwise around the Baffin Bay, to the north before heading south along the coast of Canada. Even if it is a significant amount of water that melts every year (2012 saw ice mass loss in the region of 1000 Gt), compared to the ocean currents it simply vanishes without a trace (the West Greenland at 3.8 Sverdrups moves that much water in less than 5 minutes, and the Norht Atlantic Current moves 1000 Gt every minute) and has not been shown to have any influence on the amount of heat carried by ocean currents into the Arctic (and given the amount and trajectory of the melt waters, it is difficult to see how that could happen).

So are there any scientific papers supporting the conjectured "slow down" and any cooling effect of the Greenland Ice melt on the Arctic ocean? I'd be interested to see them, I had a quick peek on Google but didn't find any.

33
Arctic sea ice / Re: The 2020 melting season
« on: May 23, 2020, 07:36:46 AM »
Regarding volume, this year has actually been following 2012 extremely colosely. January had 2012 with slightly more volume than 2020, but February and March had them neck and neck, with April again being slightly in favour of 2012. It's going to be interesting to see what May looks like!

Check out Wipneus' graph.

34
Arctic sea ice / Re: The 2020 melting season
« on: May 23, 2020, 07:09:44 AM »
La Nina is ongoing.
Being somewhat taken back by this statement (beliveng that we were currently in a neutral, even slightly positive, state), I had a quick look at the NOAA weekly analysis and was actually more surprised to see that according to them there is an ongoing El Nino! Not a very vigorous one, it must be admitted, but still, the index for the last 5 months has been at 0.5, rising to 0.6 one month, and one actually has to go back to spring 2018 to find a negative index.

Further, NOAA predicts an ever so slight change of a La Nina by fall 2020, although some predictions are much more definite, and your image does tend to support those who see a La Nina looming on the near horizon.

But an ongoing La Nina at this time? NOAA doesn't think so.

35
Arctic sea ice / Re: The 2020 melting season
« on: May 23, 2020, 05:59:50 AM »
I would be fascinated to read your interpretation of the factors which determine winter sea ice thickness in which temperature is not an important attribute.

I wont presume to answer for Friv, but speaking for my self, I think that I can easily see a situtation where winter A has lower air temperatures than winter B, but winter B ends up with thicker ice than winter A.

Difference in Fram export is perhaps the most obvious method of ending up with thinner ice in spite of lower temperatures, and ice motion in general is an important factor in determining thickness, and the temperature of the surface waters at the start of the freezing season should also be considered.

The rate of thickening slows down significantly with increased thickness. If there were no winds, waves or currents in the Arctic, and sea surface temperatures were the same going into the freezing season, thickness would be strongly correlated to air temperatues, but even a significant difference in temperatures would only result in a small difference in thickness.

If one year had higher SSTs going into the freezing season, some of the excess heat can presumably be trapped under the newly formed ice, thus hampering the rate of thickening, resulting in thinner first-year ice in spite of lower air temperatures.

And since compaction is the main source of thick multiyear ice, and compaction results not only from movement but also resistance to movement, changes in mobility in general, and direction of movement over time, could make a big difference to how thick the ice ends up being.

And I must agree with Friv, I don't see any bullying.

36
Arctic sea ice / Re: The 2020 melting season
« on: May 22, 2020, 01:32:59 PM »
Ok, thanks, I thought that "downslope" was some mystical meteorological moniker, not simply "down the mountain slope".

Acronyms can be tricky - the following is a list of the most common definitions of WAA:
Weird and Awkward
Wales, Alaska
World A Capella Association

with "Warm Air Advection" being the only meteorological one, so I should have been able to figure that out myself.  :-[

37
Arctic sea ice / Re: The 2020 melting season
« on: May 22, 2020, 12:51:45 PM »
there is a torrid downslope coming to the Beaufort.
<snip>
Assuming heights and winds come as forecasted the factor deciding how things will play out is how much sun will be accompanying the WAA downslope.

Friv, I am very grateful for how much more work you are putting into explaining things to us footlings trying to follow your soaring flight.

But I'm still at loss sometimes. What is a downslope, and what do you mean by "WAA"?

38
Arctic sea ice / Re: The 2020 melting season
« on: May 21, 2020, 06:37:42 AM »
I realize this measurement could be more accurate, but look at the size of this iceberg which was ejected out of the Fram. It made some rapid progress south and is now just floating off the eastern coast. I will continue to watch it until its eventual demise/

I was going to quibble (as usual) that it was an ice floe and not an iceberg. Then I started to think that in the Antarctic, bigger icebergs than this have been seen. So what about the Arctic, what is the biggest iceberg on record there? Turns out that it is a 100 square mile chunk that broke off Petermann glacier in 2010.

So this is a floe, quite definitely, based on size alone. And if a measurable iceberg were to break off somewhere and start drifting down the Fram I'm sure we would hear about it.

Some 300 miles further south I find a pair of floes, 600 and 400 sqmi respectively, so I guess these big floes are not that unique. But they are good fun, being easy to track.

39
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: May 19, 2020, 04:11:18 AM »
Area loss from maximum this season 2.74 million Km2, 0.45 million (20%) less than the average of 2.29 million km2.

Not that I usually quibble over small mistakes (!) but this made me scratch my head. Isn't it more correct to say that area loss is 20% more than the average to date?

I.e. the average is 2.29, loss to date is 2.74, the difference is 0.45 which is 19.65% of the average.

40
Arctic sea ice / Re: The 2020 melting season
« on: May 17, 2020, 04:31:52 AM »
Long story short, the "big" thing in the room about aerosols-affecting-clouds - is simple: the more microscopic solid particles inside clouds - the more condensation locations are available; so, same amount of water vapour which particular cloud contains - ends up condensating into more droplets (than without aerosols present). More droplets from same amount of vapour means smaller droplets. Smaller droplets means less precipitation occurs = i.e., more of the cloud remains in the air.

Thanks for this reminder. The evidence for a significant reduction in cloud cover due to the current sharp fall in aerosol pollution is getting stronger.

I mentioned earlier that I belive that most of the cloud cover that ends up in the Arctic actually originates in the mid-latitudes, coinciding with the areas seeing the biggest fall in aerosols.

But is anybody actually seeing this effect - is there less cloud cover now than usual in the mid-latitudes? Or in the Northern Hemisphere?

41
Arctic sea ice / Re: The 2020 melting season
« on: May 17, 2020, 04:21:41 AM »
<snip>  "now we are seeing Swisscheesification of the entire Arctic ..."

      Question 1:  Do those dark areas really indicate low concentration ice or does the sensor get fooled by moisture in the air column between surface and satellite? 

The "swiss cheese" is famous for it's holes, not for any "dark areas". So my comment was only regarding the holes popping up in the ice all around the perifery, much more so than usual at this time of year, as per my feeble and increasingly decrepit memory. And definitely significantly more than 2019 as can be readily seen.

The "dark areas" are of course also much more prominent than usual, or so we seem to think, but I think I've learned the lesson some time ago not to take those too literally. Althogh one does wonder if some sort of Bluecheesefication is underway as well?

42
Arctic sea ice / Re: The 2020 melting season
« on: May 16, 2020, 01:59:26 PM »
May 11-15.

2019.

That really looks scary, and even more so after comparing it to 2019. We have seen Atlantification of the Barents, now we are seeing Swisscheesification of the entire Arctic ...

43
Arctic sea ice / Re: The 2020 melting season
« on: May 16, 2020, 07:05:03 AM »
Contrails are thought to have a net warming effect, particularly as they form more readily at night rather than day. Clouds keep the planet warm.

I'm not surprised that this would be the global or average effects of contrails. But specifically in the Arctic summer months, where "night" is a dodgy subject? I'm not so sure.

As for aerosols in general, apparently the Arctic wildfires from last season have been smouldering under the snow all winter and are now reappearing in unusually large numbers. Arctic peat fires must be the biggest source of aerosols over the Arctic in a normal year? Does anyone know?

See this New Scientist article about Zombie Fires

As regards the general cloudiness of the Arctic, my feeling would be that those clouds that reach the arctic are mostly formed elsewhere, predominantly in the mid-latitudes, and given the sharp drop in aerosol pollution there, a drop in cloudiness over the Arctic would follow a general drop in cloudiness in lower latitudes - but has anybody got any idea if that is the case or not?

44
Arctic sea ice / Re: The 2020 melting season
« on: May 11, 2020, 01:38:05 PM »
Surface temps N of 80N stay close to zero because they are far away from the big heated rocks of Siberia and NA. That's why the ice remains there at the September minimum. Transporting enough heat over long distance to the surface of the CAB ice is not a trivial matter.

Always interesting to read new theories of physics and meteorology in this forum.

I wonder why people think that the landmasses of Alaska and Sibera are more significant sources of heat in summer, than are the open ocean areas surrounding the ice. The open ocean absorbs much more solar energy than does dry land, has a much higher heat capacity, and has the ability to move the heat to the ice directly rather than going through the ethereal media of air.

Without the landmasses surrounding the Arcitic Ocean, I'd guess that the ice would disappear every summer. If there was no Antarctic Continent and just open ocean on the South Pole, it would lose all it''s ice every summer (methinks). It's the presence of the vast Antartic landmass that maintains the antarctic sea ice, and the same can be said for the Arctic Ocean, the ice survives by sheltering behind the landmass of America in particular, Siberia to a lesser extent.

45
Arctic sea ice / Re: The 2020 melting season
« on: May 02, 2020, 12:44:08 PM »
Can you see the bear? Anyhow, from the accompanying note posted at nasa.gov, we can read that the bear is, quote, "standing behind Met City near a small lead, likely waiting for a seal". Earlier in the note, we also read that bear, quote, "... sat near a small crack in the ice for almost two hours, likely waiting for a seal to surface".  Seals, i understand, would need open water to come onto the ice, where polar bears could hunt them.

Sometimes when you think something is general knowledge ... but apparently not. Seals nead to breathe. They maintain breathing holes in the ice. Polar bears seek out these breathing holes and wait patiently, up to several hours (often hiding their black snout with a small clump of ice). If the seal does take the change to stick it's nose up for a quick gulp of breath, the waiting polar bear clobbers it and draws it up onto the ice. Seals do NOT crawl onto the ice where polar bears "can hunt them"!

The seal creates breathing holes in the ice as it is forming in the fall, and can maintain them all winter with their paws, sometimes through as much as 2m of ice. But of course, once the ice starts moving and shifting, the seals probably get tempted to use the leads that open op in this way as well, maintaining a short-term breathing hole in a rapidly refreezing lead.

The polarstern people probably were seeing the latter, since they most certainly would have noticed the "aglus" or proper breathing holes if they had been in their vicinity.

46
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: April 18, 2020, 06:51:58 PM »
2) Distance from a large heat advecting land mass. The second criteria is the more dominant variable and has a tad more nuance.

I'm not sure if being close to a landmass is better than being close to open ocean. The oceans absorb much more radiation than land, and the heat transfer of ocean currents has vastly larger potentiality than wind-driven heat transfer by air.

As discussed upstream, the density gradient is a roadblock to ocean heat making it to the surface where the ice is located. The salt in the warm Atlantic ocean water makes it too dense. There's abundant heat in the Arctic Ocean lurking in the subsurface layer below the freshwater lens.


Which is basic knowledge in this forum. And has nothing to do with my (perhaps badly) made point. Which is this:  Open ocean absorbs heat from the sun, no matter what the density. Open land absorbs much less heat.

Your earlier post seemed to indicate that ice being close to a landmass would somehow receive a warming boost because of air advecting over the warmed-up land and out over the ice. But I would say that being far away from a landmass would give added boost to melt during summer, by air advecting over open ocean which, as I've said, absorbs much more heat than dry land and has therefore more heat to give to any passing air (besides being able to transfer the heat itself to some extent).

47
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: April 15, 2020, 08:18:21 AM »
I guess apocoalypticists are constantly seeing signs of imminent collapse. And have been since at least Ramses' time. I on the other hand, who am absolutely certain that our human civilisation will survive both Covid-19 and AGW, see amazing resilience and innovative adaptation everywhere.

It's clear we disagree here, but that is okay :)

I simply don't see civilization surviving the possible 4-6 C rise this century, I do think human societies can be rebuilt though in certain regions.

Well, lots of things have the capacity to totally wreck human civilisation. But I do not think it is remotely likely that it will happen this century, or that it will happen because of AGW. A rise of 4-6 degrees is not going to happen.

But a lot of people seem to have an apocalyptic deathwish on behalf of their fellow humans. Myself I find it a loathsome attitude.

48
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: April 15, 2020, 07:55:06 AM »
2) Distance from a large heat advecting land mass. The second criteria is the more dominant variable and has a tad more nuance.

I'm not sure if being close to a landmass is better than being close to open ocean. The oceans absorb much more radiation than land, and the heat transfer of ocean currents has vastly larger potentiality than wind-driven heat transfer by air.

49
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: April 15, 2020, 07:20:32 AM »
      The Sept. ice is not centered around 90N anyway, but is centered south of 90N on the Greenland/Canadian side.  The location of the remaining Sept. ice does not match bathymetry very well.  So I don't see that as a saving grace either.  Protection by location matters even less when you factor in the increasing mobility of thinning ice, reduction of land-fast ice, increased open water/wind fetch, increased warm air incursion, and increased melt season storm potential as greenhouse gas loading and global heating exacerbated by Arctic amplification continue.

Absolutely!

50
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: April 15, 2020, 04:44:19 AM »
I guess apocoalypticists are constantly seeing signs of imminent collapse. And have been since at least Ramses' time. I on the other hand, who am absolutely certain that our human civilisation will survive both Covid-19 and AGW, see amazing resilience and innovative adaptation everywhere.

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