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Iceismylife

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Re: Ice-free Arctic
« Reply #350 on: March 28, 2018, 11:25:18 PM »
My assumptions justifying thinking the gulf stream will find its way into the arctic ocean.

1. A BOE will let the stratification of the arctic ocean be disrupted by wave action.

2. when the sun sets and things cool off with the stratification a thing of the past you get bottom water production rather than ice.

3. what drives the currents around Greenland and the CAA currently is the Earth's rotation the warmth coming up from the equator (gulf stream) and the large freshwater input from ice melt and run off.

4. it is the cold reduced salinity run off water plus ocean water surface water current that pushes the gulf stream away from the east coat of north America.

The freshwater mixes with surface water, if that becomes bottom water then the surface water needs to be replaced.  The cold water would sink rather than stay on the surface.  So instead of a current coming out of the arctic ocean past Greenland you would have a current going in instead.

No current pushing the gulf stream east.  So it would go north into the arctic ocean.

With 20C water coming into the arctic basin you could see 20C air temps over the water and storms like there was no tomorrow.

Ken Feldman

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Re: Ice-free Arctic
« Reply #351 on: March 28, 2018, 11:27:58 PM »
I don't care if an article is peer reviewed. It it contradicts my perception of reality I'll challenge it. This models predicts extraordinary growth that no one has ever witnessed before.

 I'll tell you exactly the mistake of the model.

The model assumes that after November, Arctic temperatures return to average. The average temps remain average even while generating record ice growth until April.

That's the opposite of the observations. So far the surface temperature anomalies last until April and ice has not grown at the incredible rate required by this model. There is something seriously wrong with it. The part of my reply that you didn't address explains why, let me repeat their assumption:

Quote
For SAT a large positive anomaly occurs between October and February after the initial perturbation, with a peak of almost 11 K in November (Figure 2). After February, there are no further SAT anomalies stronger than natural variability.

We are already at 5-8 K winter anomaly that last until April.  Yet you want me believe that after the first BOE all that extra heat will be vented out to of the arctic system? That makes no sense.

The record low ice extent to date was in 2012.  Here's how the 80N temperatures responded (note the below average temperatures in February):



The sea ice extent in 2012 bottomed out at 3.39 million square kilometers.  In 2013 the minimum was 5.05 million square kilometers.  So somehow, 1.66 million square kilometers of exceedingly thin first year ice survived.

Ken Feldman

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Re: Ice-free Arctic
« Reply #352 on: March 28, 2018, 11:41:04 PM »
My assumptions justifying thinking the gulf stream will find its way into the arctic ocean.

1. A BOE will let the stratification of the arctic ocean be disrupted by wave action.

2. when the sun sets and things cool off with the stratification a thing of the past you get bottom water production rather than ice.

3. what drives the currents around Greenland and the CAA currently is the Earth's rotation the warmth coming up from the equator (gulf stream) and the large freshwater input from ice melt and run off.

4. it is the cold reduced salinity run off water plus ocean water surface water current that pushes the gulf stream away from the east coat of north America.

The freshwater mixes with surface water, if that becomes bottom water then the surface water needs to be replaced.  The cold water would sink rather than stay on the surface.  So instead of a current coming out of the arctic ocean past Greenland you would have a current going in instead.

No current pushing the gulf stream east.  So it would go north into the arctic ocean.

With 20C water coming into the arctic basin you could see 20C air temps over the water and storms like there was no tomorrow.

Climate models show that a slow down of the Gulf Stream (actually the Atlantic Meriodonal Overturning Current, or AMOC) is more likely due to global warming.  There's a good summary of it here:  https://e360.yale.edu/features/will_climate_change_jam_the_global_ocean_conveyor_belt

Quote
A huge amount of heat is moved around our planet by a single ocean current system — the Atlantic Meridional Overturning Circulation (AMOC) — which accounts for up to a quarter of the planet’s heat flux. The system is driven by density: waters that are cold or salty are denser and so dive down to the ocean floor. As a result, today, cold waters sink in the North Atlantic and flow southwards, while warm tropical waters at the surface flow northwards in the Gulf Stream, making northern Europe unusually mild for its latitude. But if northern waters get too warm, or too fresh from melting ice, then they can stop being dense enough to sink. That causes a major traffic jam for the water attempting to move north, and the system grinds to a halt.

...

If the North Atlantic current slows dramatically, then the entire Northern Hemisphere would cool; a complete collapse of the current could even reverse global warming for about 20 years. But the heat that ocean currents fail to transport northwards would make parts of the Southern Hemisphere even hotter. And a cooler north isn’t necessarily good news. Should the AMOC shut down, models show that changes in rainfall patterns would dry up Europe’s rivers, and North America’s entire Eastern Seaboard could see an additional 30 inches of sea level rise as the backed-up currents pile water up on East Coast shores.

Archimid

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Re: Ice-free Arctic
« Reply #353 on: March 29, 2018, 12:17:46 AM »
Quote
The sea ice extent in 2012 bottomed out at 3.39 million square kilometers.  In 2013 the minimum was 5.05 million square kilometers.

The 2012-2013 freezing season had the record volume gain at the time at 19.063 x 1000km^2. Then it lost 17.04 during the melting season for a total volume gain of 1.79, year over year. In that cycle the Arctic grew. The 2013-2014 freezing season was much weaker at 17.726 but the melting season was the weakest since 2007 for a net year over year gain of 1.42.

In both years the gains exceeded the losses thus we had two years in a row of volume growth. But only in one of those years was record gains obtained.

Both 2016 and 2017 had similarly low volumes but they only gained 17.031. For both seasons winter temperatures remained highly anomalously warm for the whole season.
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Iceismylife

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Re: Ice-free Arctic
« Reply #354 on: March 29, 2018, 02:11:54 AM »

...

Climate models show that a slow down of the Gulf Stream (actually the Atlantic Meriodonal Overturning Current, or AMOC) is more likely due to global warming.  There's a good summary of it here:
...
climate models are based on assumptions.  I don't forget 2012 reaching the median prediction for 2100 in sea ice extent.  I am not impressed with models predictive ability.  (I predicted that Katrina would turn and hit New Orleans when they had it hitting Mexico.  The same with the next one.  I said the next one would go straight they said it would turn and it did. I was 2 for 3 they were 1 for 3)

Nice article. 

Has anyone modeled open water in the arctic?


crandles

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Re: Ice-free Arctic
« Reply #355 on: March 29, 2018, 12:41:45 PM »

...

Climate models show that a slow down of the Gulf Stream (actually the Atlantic Meriodonal Overturning Current, or AMOC) is more likely due to global warming.  There's a good summary of it here:
...
climate models are based on assumptions.  I don't forget 2012 reaching the median prediction for 2100 in sea ice extent.  I am not impressed with models predictive ability.  (I predicted that Katrina would turn and hit New Orleans when they had it hitting Mexico.  The same with the next one.  I said the next one would go straight they said it would turn and it did. I was 2 for 3 they were 1 for 3)

Nice article. 

Has anyone modeled open water in the arctic?

Perhaps see
https://forum.arctic-sea-ice.net/index.php/topic,2286.msg560/

johnm33

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Re: Ice-free Arctic
« Reply #356 on: March 29, 2018, 01:07:11 PM »
My assumptions justifying thinking the gulf stream will find its way into the arctic ocean.

1. A BOE will let the stratification of the arctic ocean be disrupted by wave action.

2. when the sun sets and things cool off with the stratification a thing of the past you get bottom water production rather than ice.

3. what drives the currents around Greenland and the CAA currently is the Earth's rotation the warmth coming up from the equator (gulf stream) and the large freshwater input from ice melt and run off.

4. it is the cold reduced salinity run off water plus ocean water surface water current that pushes the gulf stream away from the east coat of north America.

The freshwater mixes with surface water, if that becomes bottom water then the surface water needs to be replaced.  The cold water would sink rather than stay on the surface.  So instead of a current coming out of the arctic ocean past Greenland you would have a current going in instead.

No current pushing the gulf stream east.  So it would go north into the arctic ocean.

With 20C water coming into the arctic basin you could see 20C air temps over the water and storms like there was no tomorrow.
I see 3/4 very differently, take a look at the currents here water rises off of Africa and whether due to coming from the deep, or from nearer the poles, is moving slower than the Earth, it is driven west. It ends up in the Carribean where it overflows and moves north, the surface speed rapidly changes as the water moves north, but the water still slower hugs the coast, then @350 or thereabouts the waters inertia is faster than surface speed and separates from the coast, flowing east.
 From there its path is determined by the path of least resistance, if there was no net flow from the Arctic either as fresher water coming down through Labrador, or strongly saline falling into the deep, Denmark strait etc., there'd be no physical reason for that water to move north. Despite some metrics to the contrary the evidence of more Gulf waters penetrating deeper into the  Arctic speaks to an accelerated rate of turnover.
I don't think it's useful to make any particular case since so many variables are in play, but I do expect to see a tidal signature emerging and contributing to the destruction of the ice this year, more on the Atlantic side but not confined to it.

Iceismylife

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Re: Ice-free Arctic
« Reply #357 on: March 29, 2018, 06:12:23 PM »
I see 3/4 very differently, take a look at the currents here water rises off of Africa and whether due to coming from the deep, or from nearer the poles, is moving slower than the Earth, it is driven west. It ends up in the Carribean where it overflows and moves north, the surface speed rapidly changes as the water moves north, but the water still slower hugs the coast, then @350 or thereabouts the waters inertia is faster than surface speed and separates from the coast, flowing east.
 From there its path is determined by the path of least resistance, if there was no net flow from the Arctic either as fresher water coming down through Labrador, or strongly saline falling into the deep, Denmark strait etc., there'd be no physical reason for that water to move north. Despite some metrics to the contrary the evidence of more Gulf waters penetrating deeper into the  Arctic speaks to an accelerated rate of turnover.
I don't think it's useful to make any particular case since so many variables are in play, but I do expect to see a tidal signature emerging and contributing to the destruction of the ice this year, more on the Atlantic side but not confined to it.
A blue ocean event means more heat transfer from the water to the environment.  That means one of two things.  More ice production or more bottom water production.  Accelerated rate of turnover that is what I think will happen.

Bottom water generation in the CAB means the surface water will come from somewhere else. 



Here is where I've been looking.   You've talked about flow separation.  The Gulf Stream separates about @350. If you pull surface water north into the CAB then you should pull the Gulf Stream too.  Boundary layer control.

Ken Feldman

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Re: Ice-free Arctic
« Reply #358 on: March 29, 2018, 07:37:33 PM »
Quote
The sea ice extent in 2012 bottomed out at 3.39 million square kilometers.  In 2013 the minimum was 5.05 million square kilometers.

The 2012-2013 freezing season had the record volume gain at the time at 19.063 x 1000km^2. Then it lost 17.04 during the melting season for a total volume gain of 1.79, year over year. In that cycle the Arctic grew. The 2013-2014 freezing season was much weaker at 17.726 but the melting season was the weakest since 2007 for a net year over year gain of 1.42.

In both years the gains exceeded the losses thus we had two years in a row of volume growth. But only in one of those years was record gains obtained.

Both 2016 and 2017 had similarly low volumes but they only gained 17.031. For both seasons winter temperatures remained highly anomalously warm for the whole season.

Volume has increased despite the warmer winters:



It just might be because even as "warm" as the previous winters have been, they haven't come close to reaching the melt point of ice:


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Re: Ice-free Arctic
« Reply #359 on: March 29, 2018, 11:30:42 PM »
Quote
It just might be because even as "warm" as the previous winters have been, they haven't come close to reaching the melt point of ice:

The thermodynamic ice thickness growth rate is a function of time and temperature. The metric used to calculate that function is the Freezing Degree Day. You can read about it here:

 https://nsidc.org/cryosphere/seaice/processes/thermodynamic_growth.html

 Tealight has a nice set of graphs describing FDD behavior over the last several years here:

https://sites.google.com/site/cryospherecomputing/fdd

Quote
Volume has increased despite the warmer winters:

Do you mean 2017/2018 volume increased relative to 2016/2017? Of course. See the FDD graphs above. 2016/17 was the warmest winter on record, so it follows that that it had a very low volume gain. Luckily, 2017 had the second smallest volume loss since 2014. That left the volume minimum in a good position to overtake 2017/2018 even if it was almost as warm.

2017/2018 my yet surprise. If the Bering situation results in a chukchi/beufort/ess situation, Volume Maximum might reach record low.
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Ken Feldman

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Re: Ice-free Arctic
« Reply #360 on: March 30, 2018, 01:23:38 AM »
Quote
It just might be because even as "warm" as the previous winters have been, they haven't come close to reaching the melt point of ice:

The thermodynamic ice thickness growth rate is a function of time and temperature. The metric used to calculate that function is the Freezing Degree Day. You can read about it here:

 https://nsidc.org/cryosphere/seaice/processes/thermodynamic_growth.html

 Tealight has a nice set of graphs describing FDD behavior over the last several years here:

https://sites.google.com/site/cryospherecomputing/fdd

Quote
Volume has increased despite the warmer winters:

Do you mean 2017/2018 volume increased relative to 2016/2017? Of course. See the FDD graphs above. 2016/17 was the warmest winter on record, so it follows that that it had a very low volume gain. Luckily, 2017 had the second smallest volume loss since 2014. That left the volume minimum in a good position to overtake 2017/2018 even if it was almost as warm.

2017/2018 my yet surprise. If the Bering situation results in a chukchi/beufort/ess situation, Volume Maximum might reach record low.

Tealight's graphs seem to undercalculate the thickness of the ice.  Compare the graph, which calculates a current ice thickness of 150 cm to the map showing the current ice thickness:

Tealight's graph.

Current ice thickness and volume from DMI

It seems that the simple formula leaves out a lot of real life situations.  Here's what NSIDC says on the page you linked: 
Quote
The ice thickness increases at a rate roughly proportional to the square root of the cumulative FDD. Formulas such as this are empirical, meaning they are calculated only with observed data, so they really are simplifications of the ice growth processes. The formulas assume that the ice growth occurs in calm water and is reasonably consistent, and they do not take into account sea ice motion, snow cover, and other surface conditions.

NSIDC has a good page summarizing how sea ice forms.  Here's a link:https://nsidc.org/cryosphere/seaice/characteristics/formation.html

The wind and waves can cause forming ice sheets to raft over each other (becoming thicker) and crash into each other, forming ridges. From the link above:

Quote
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.

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Re: Ice-free Arctic
« Reply #361 on: March 30, 2018, 03:02:39 AM »
Quote
Tealight's graphs seem to undercalculate the thickness of the ice.  Compare the graph, which calculates a current ice thickness of 150 cm to the map showing the current ice thickness:

yes of course and he says so on his site:

Quote
It is important to note that the calculated thickness using this formula only accounts for the freezing of sea water and not ice growth from snowfall, freezing rain or ridging

FDD calculations alone are not meant to determine the exact thickness of the ice. However, they do show the potential temperature based thickness of the ice. Like all data, you have to take it for what it is.

What I want you to understand is that ice formation is not a binary function "below freezing", "not below freezing". Ice formation speeds up the colder it is. FDD's as illustrated by Tealight show how Arctic winter temperatures increased over time.
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crandles

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Re: Ice-free Arctic
« Reply #362 on: March 30, 2018, 12:08:55 PM »
What I want you to understand is that ice formation is not a binary function "below freezing", "not below freezing". Ice formation speeds up the colder it is. FDD's as illustrated by Tealight show how Arctic winter temperatures increased over time.


But aren't higher temperatures a sign of higher hear transfer from the ocean and heat transfer from the ocean is a pretty direct measure of ice formation (once and surplus heat built up over summer has been vented)?

Resolving cause and effect can be tricky.

If you are believing the major mechanisms are GHGs control air temperatures and temperatures control heat loss from ocean which controls ice formation then you are ignoring a different directional causation:

Heat loss from ocean controls both the air temperature and ice formation.

If the major causation direction was GHGs controlling temperatures then temperature rises would be more throughout the year. I think the temperatures rises are greatest when the ice is thinner than normal. eg 2017 maximum ice particularly low and winter temperatures were high. So I think the major direction of causation is from heat loss from oceans. Not saying there isn't some causation effect of air temperatures but it doesn't seem like the main causation direction.

Edit: This is probably dangerous reasoning is the temp high because the ice is thin or is the ice thin because the temps are high? Better reasoning might involve figuring out which comes first.
« Last Edit: March 30, 2018, 12:14:47 PM by crandles »

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Re: Ice-free Arctic
« Reply #363 on: March 30, 2018, 02:45:08 PM »
Quote
But aren't higher temperatures a sign of higher hear transfer from the ocean and heat transfer from the ocean is a pretty direct measure of ice formation (once and surplus heat built up over summer has been vented)?

I think a key point of my argument is that a significant portion of the extra heat is not being vented outside the Arctic system, changing both temperatures and gradients between the atmosphere and the oceans. At least not in the last three years of record hot winter temperatures.

Quote
If you are believing the major mechanisms are GHGs control air temperatures and temperatures control heat loss from ocean which controls ice formation then you are ignoring a different directional causation:

GHG's are certainly important, but the biggest change in heat transfers right now seems to be advection from the peripheral atmosphere into the Arctic. I think the changes in the atmospheric currents increase the exchange of heat between the Arctic and the rest of the Northern hemisphere resulting in a much warmer arctic and a slightly cooler rest of the world. I think that's why global models are slightly overestimating global warming but Arctic models are strongly underestimating sea ice losses. 

Quote
Heat loss from ocean controls both the air temperature and ice formation.

I can certainly agree that other than the sun (or lack thereof), ocean temperatures and heat transfers from ocean to atmosphere are one of the most important factors in Arctic temperatures.

Quote
If the major causation direction was GHGs controlling temperatures then temperature rises would be more throughout the year.

I think the causation line goes like this

1. GHG's cause global warming->
2. Global warming causes changes in the atmospheric currents->
3. Changes in the atmospheric currents cause an increase in advection into the Arctic->
4. Increase advection results in changes of the ice->
5. Changes of the ice cause changes in atmospheric currents->
6. Go Back to 3

Quote
I think the temperatures rises are greatest when the ice is thinner than normal.

Agreed.

Quote
So I think the major direction of causation is from heat loss from oceans

I think heat loss from the oceans will increase in impact as the ice gets thinner and is gone for longer.  There will be more heat entering the ocean  in summer. That heat will vent in to the atmosphere raising temperatures and slowing down ice growth. Some of that heat will go out into space, but a significant portion stays in the climate system becoming a positive feedback for temperature.

Quote
This is probably dangerous reasoning is the temp high because the ice is thin or is the ice thin because the temps are high? Better reasoning might involve figuring out which comes first.

Both are true, but the cycle started with higher temperatures turning ice thin.
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Ken Feldman

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Re: Ice-free Arctic
« Reply #364 on: March 30, 2018, 06:06:04 PM »
What I want you to understand is that ice formation is not a binary function "below freezing", "not below freezing". Ice formation speeds up the colder it is. FDD's as illustrated by Tealight show how Arctic winter temperatures increased over time.

This statement is incorrect.  Ice formation is a binary function of below freezing and not below freezing.  Once seawater gets below the freezing point, -1.8 C, ice crystals will form.  It's basic physics.

After that, sea ice thickness is determined by other factors, including wind and snow.  Wind and snow help thicken the ice sheet.  The wind by allowing more heat to dissipate through the ice, and snow by weighing down the ice and allowing more snow ice to form.

Snow also helps to protect the ice during the melt season through it's higer albedo.  Here's a link to a paper about observations of snow on ice during the 2015 spring:  https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2017GL075494

From the introduction of the paper: 
Quote
Snow on sea ice is a critical physical parameter that modulates the growth and decay of sea ice (Maykut, 1978; Sturm & Massom, 2010). In spring, when solar insolation is high, even little snow fall on Arctic sea ice can significantly slow down surface melt, due to the snow’s high albedo (Perovich et al., 2017). In winter, when sea ice grows in the absence of solar insolation in the high Arctic, the role of snow is twofold. Snow insulates the sea ice surface from cold air temperatures, hindering thermodynamic growth of sea ice (Ledley, 1991; Maykut, 1978). However, snow can also contribute to the sea ice mass balance through the formation of snow-ice (e.g., Leppäranta, 1983). Snow-ice forms when seawater floods and refreezes at the ice/snow interface, due to excessive snow load that pushes the ice surface below sea level. Snow-ice is a common process in seasonally ice-covered seas but has not been prevalent in the Arctic, where thick perennial sea ice has dominated (Sturm & Massom, 2010).

So a few degrees of warming during the winter, provided that the temperatures stay below freezing (resulting in new ice crystals forming in leads and snow falling on that ice), don't prevent new ice from forming.  That's why models predict that the Arctic will become a seasonal ice sheet (similar to Antarctica or the Sea of Okhotsk), not ice free all year.

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Re: Ice-free Arctic
« Reply #365 on: March 30, 2018, 06:22:53 PM »
Quote
This statement is incorrect.  Ice formation is a binary function of below freezing and not below freezing.  Once seawater gets below the freezing point, -1.8 C, ice crystals will form.  It's basic physics.

Are you arguing that temperatures have no significant bearing on ice formation rate?

Quote
After that, sea ice thickness is determined by other factors, including wind and snow.  Wind and snow help thicken the ice sheet.  The wind by allowing more heat to dissipate through the ice, and snow by weighing down the ice and allowing more snow ice to form.

Woosh. Most ice formation is due to bottom growth. That growth is completely dependent on the gradient of temperature of the water with the atmosphere. The colder it is the larger the gradient producing more ice.

Of course, snow and frozen rain do add to the total but that number is much smaller than bottom growth.

Quote
Snow also helps to protect the ice during the melt season through it's higer albedo.  Here's a link to a paper about observations of snow on ice during the 2015 spring:


Did you even read that abstract to the end? Read the last sentence.

Quote
So a few degrees of warming during the winter, provided that the temperatures stay below freezing (resulting in new ice crystals forming in leads and snow falling on that ice), don't prevent new ice from forming.  That's why models predict that the Arctic will become a seasonal ice sheet (similar to Antarctica or the Sea of Okhotsk), not ice free all year.

Sure a few degrees will of course result in almost unnoticeable effects but the warmer it gets the less growth you get through bottom melt.
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Ken Feldman

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Re: Ice-free Arctic
« Reply #366 on: March 30, 2018, 08:51:24 PM »
Quote
This statement is incorrect.  Ice formation is a binary function of below freezing and not below freezing.  Once seawater gets below the freezing point, -1.8 C, ice crystals will form.  It's basic physics.

Are you arguing that temperatures have no significant bearing on ice formation rate?

Quote
After that, sea ice thickness is determined by other factors, including wind and snow.  Wind and snow help thicken the ice sheet.  The wind by allowing more heat to dissipate through the ice, and snow by weighing down the ice and allowing more snow ice to form.

Woosh. Most ice formation is due to bottom growth. That growth is completely dependent on the gradient of temperature of the water with the atmosphere. The colder it is the larger the gradient producing more ice.

Of course, snow and frozen rain do add to the total but that number is much smaller than bottom growth.

Quote
Snow also helps to protect the ice during the melt season through it's higer albedo.  Here's a link to a paper about observations of snow on ice during the 2015 spring:


Did you even read that abstract to the end? Read the last sentence.

Quote
So a few degrees of warming during the winter, provided that the temperatures stay below freezing (resulting in new ice crystals forming in leads and snow falling on that ice), don't prevent new ice from forming.  That's why models predict that the Arctic will become a seasonal ice sheet (similar to Antarctica or the Sea of Okhotsk), not ice free all year.

Sure a few degrees will of course result in almost unnoticeable effects but the warmer it gets the less growth you get through bottom melt.

The thickness maps show ice 3 to 4 meters thick in areas north of 80N, where the temperatures have been been warmer in winter.  So I'm arguing that the effects of rafting, ridging and snow ice formation can offset the slower bottom growth from the above average temperatures and delay the complete melt out of the Arctic ice.  These mechanisms will also allow the Arctic ice the reform in winters after it eventually goes ice-free in summers, becoming a seasonal ice sheet, like the Antarctic sea ice.

And I did read the entire article, not just the abstract.  With more storms, you get more snow on the thinner ice.  That leads to more snow-ice formation and the protective albedo effect.  From the discussion section of the article that explains the last sentence of the abstract (emphasis added):

Quote
Mean precipitation from 1980 to 2016 shows the highest precipitation in the Atlantic sector of the Arctic (Figure S2b). This region is characterized by a larger number of autumn and winter storm events (Graham, Rinke, et al., 2017; Graham, Cohen, et al., 2017; Rinke et al., 2017; Woods & Caballero, 2016; Zhang et al., 2004). This is largely due to the influence of North Atlantic Ocean. High precipitation in this region is supported by the deep (>50 cm) snowpacks observed in this region during spring field campaigns in 2015 (Merkouriadi, Gallet, Graham, et al., 2017) and 2017 (M. Granskog; M. Nicolaus, personal communication, 2017). Given the recent observations of thicker snow cover and thinning of the ice cover in the Atlantic sector
of the Arctic (Renner et al., 2014; Rösel, Divine, et al., 2016; Rösel, Polashenski, et al., 2016), we surmise the potential for snow-ice formation in this region is the largest in the Arctic Ocean but can become imminent in larger areas when the ice is thinning.

In autumn and winter of 2014–2015, frequent storm events brought heavy precipitation and positive air temperature anomalies to our study region (Figures 1a and 1b). These storms are also associated with sustained 6-hourly wind speeds above 10 m s1, according to the ERA-I reanalysis (Merkouriadi, Gallet, Graham, et al., 2017). These strong winds initially come from the south and advect warm and moist air from the North Atlantic into the Central Arctic, resulting in heavy precipitation and positive temperature anomalies (Cohen et al., 2017; Kayser et al., 2017; Woods & Caballero, 2016). It is clear from our results that these storm events, and associated precipitation and temperature changes, play a crucial role in the growth, development, and structure of FYI. The impact of these storms in relation to the growth onset of FYI needs to be considered in sea ice modeling studies.

Archimid

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Re: Ice-free Arctic
« Reply #367 on: March 30, 2018, 09:15:04 PM »
Quote
The thickness maps show ice 3 to 4 meters thick in areas north of 80N

That's mostly due to multiyear ice accumulating yearly excess ice.

I'll ask again, because you are making it sound like temperatures don't matter for ice formation, when I believe it is the major component of ice formation. Yet you are not saying it straight up, you are simply dancing around it. I'm very confused.

To your understanding, does it matter how cold it gets or is it simply enough to reach the minimum freezing point? If it does matter, what percentage of the ice is made through bottom growth and what percentage is made by snow/rain/ridging.
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Re: Ice-free Arctic
« Reply #368 on: March 31, 2018, 12:54:49 AM »
Quote
The thickness maps show ice 3 to 4 meters thick in areas north of 80N

That's mostly due to multiyear ice accumulating yearly excess ice.

I'll ask again, because you are making it sound like temperatures don't matter for ice formation, when I believe it is the major component of ice formation. Yet you are not saying it straight up, you are simply dancing around it. I'm very confused.

To your understanding, does it matter how cold it gets or is it simply enough to reach the minimum freezing point? If it does matter, what percentage of the ice is made through bottom growth and what percentage is made by snow/rain/ridging.

Both are important, but ridging and rafting is obviously capable of adding more thickness than thermodynamic processes.  This is from a site on the Antartic sea ice, but the physical processes are the same:

Quote
Analysis of the pack shows that deformation, rather than basal freezing, is the dominant mechanism for increasing ice thickness beyond 0.2-0.4 m. This results in an increase in local ice thickness whilst at the same time opening leads where, during the growth season, new ice is able to form. The net effect is increased ice production resulting in an increase in the total mass of ice within the pack, and subsequent changes in the ice thickness distribution.
 

Here's a link to the site:  http://aspect.antarctica.gov.au/home/about-sea-ice/ridging-and-rafting

And here's a follow-up to the paper on storms in the North Atlantic helping the ice to grow:

Quote
As the Arctic sea ice cover continues to thin, convergent sea ice motion can more readily pile up ice into large ridges. Such ridges can be hazardous to marine activities in the Arctic. Divergent ice motion produces openings in the ice called leads, where new ice can readily grow. Winds are the main driver for both ridging and lead formation. A single storm event can lead to significant redistribution of sea ice mass through ridging and new leads. As part of the Norwegian Young Sea ICE (N-ICE2015) expedition, colleagues at the Norwegian Polar Institute made detailed sea ice thickness and ice drift observations before and after a storm in an area north of Svalbard (Figure 5). Results showed that about 1.3 percent of the level sea ice volume was pressed together into ridges. Combined with new ice formation in leads, the overall ice volume increased by 0.5 percent. While this is a small number, sea ice in the North Atlantic is typically impacted by 10 to 20 storms each winter, which could account for 5 to 10 percent of ice volume each year.
  The source for that story is the NSIDC website at this link: http://nsidc.org/arcticseaicenews/2018/02/




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Re: Ice-free Arctic
« Reply #369 on: March 31, 2018, 02:57:26 AM »
Both are important, but ridging and rafting is obviously capable of adding more thickness than thermodynamic processes. 

That may be true for Antarctica, but as your second link measured, it is not the same for the arctic.

Quote
This is from a site on the Antartic sea ice, but the physical processes are the same:

Similar in many ways, very different in others. I think the real big difference is that Antarctica is an ice sheet on top of the continent surrounded by the ocean. The center is ready an primed to grow with a gigantic ice sheet on top priming all the surrounding ocean with fresh water and very high albedo.

The Arctic is the polar opposite. An ocean covered in a sheet of ice surrounded by mostly land. The land no longer has ice on it except for Greenland. See NSIDC take on that.

https://nsidc.org/cryosphere/seaice/characteristics/difference.html

Quote
Because sea ice does not stay in the Antarctic as long as it does in the Arctic, it does not have the opportunity to grow as thick as sea ice in the Arctic. While thickness varies significantly within both regions, Antarctic ice is typically 1 to 2 meters (3 to 6 feet) thick, while most of the Arctic is covered by sea ice 2 to 3 meters (6 to 9 feet) thick. Some Arctic regions are covered with ice that is 4 to 5 meters (12 to 15 feet) thick.

Quote
And here's a follow-up to the paper on storms in the North Atlantic helping the ice to grow:
...
 Results showed that about 1.3 percent of the level sea ice volume was pressed together into ridges. Combined with new ice formation in leads, the overall ice volume increased by 0.5 percent. While this is a small number, sea ice in the North Atlantic is typically impacted by 10 to 20 storms each winter, which could account for 5 to 10 percent of ice volume each year.
 

So 5-10 percent in the peripheral seas. I bet much less in the inner basin.

Once the arctic is ice free the ice will probably form in a similar way as Antarctica. Except that in Antarctica the ice radiates out of a frozen continent while in the Arctic it will grow from the outside in with no ice sheet to help except for the northern coast of Greenland.


At the end of the year whatever ice is left will be 1 year ice of record low extent and volume. That ice will melt the following year even quicker than before, allowing more heat to enter the system, further delaying the freezing season. Rinse and repeat.

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Re: Ice-free Arctic
« Reply #370 on: March 31, 2018, 07:47:02 PM »
Once the arctic is ice free the ice will probably form in a similar way as Antarctica. Except that in Antarctica the ice radiates out of a frozen continent while in the Arctic it will grow from the outside in with no ice sheet to help except for the northern coast of Greenland.


At the end of the year whatever ice is left will be 1 year ice of record low extent and volume. That ice will melt the following year even quicker than before, allowing more heat to enter the system, further delaying the freezing season. Rinse and repeat.

I generally agree with this with regards to how the ice will behave when we reach a BOE at the end of the melt season. Since this is defined as less than 1 million square km, there will be still be rafts of dispersed floes randomly across the CAB that may even blink out on SIE measures as the concentrations are below 15%. There will also still be dispersed floes in concentrations high enough to be measured as extent in and about the CAA. Heading into the winter, the ice will then form pretty much as you described, along the shores but also around these patches of ice that remain after the melt season. In the polar winter, the growth in extent will be quite rapid although the physical characteristics will be quite different (pancake ice etc) due to storminess etc. Entering the next melt season, we will find ice across much/most of the CAB and in the peripheral seas, much as we do today with the exception that it will be thinner, more mobile and prone to melt out faster.

Wash, rinse, repeat than becomes seasonal BOE with winter ice cover that fails to meet the definition of BOE.

There is a very real possibility IMO that an odd equilibrium will exist where at the height of the freeze season you find large expanses of ice along the shores across the Arctic , with a violent, treacherous, ice filled, stormy, open ocean winter in the center of the CAB. Think Bering Sea but much nastier.
« Last Edit: March 31, 2018, 07:53:14 PM by Shared Humanity »

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Re: Ice-free Arctic
« Reply #371 on: March 31, 2018, 11:46:27 PM »
...
There is a very real possibility IMO that an odd equilibrium will exist where at the height of the freeze season you find large expanses of ice along the shores across the Arctic , with a violent, treacherous, ice filled, stormy, open ocean winter in the center of the CAB. Think Bering Sea but much nastier.
...and that will bring in the heat of the gulf stream.

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Re: Ice-free Arctic
« Reply #372 on: April 01, 2018, 07:09:49 PM »
...
There is a very real possibility IMO that an odd equilibrium will exist where at the height of the freeze season you find large expanses of ice along the shores across the Arctic , with a violent, treacherous, ice filled, stormy, open ocean winter in the center of the CAB. Think Bering Sea but much nastier.
...and that will bring in the heat of the gulf stream.

Heat from the Pacific and Atlantic current is already being transported into the Arctic Ocean and if the Arctic Ocean were not as protected as it is from warmer waters, I think an all year long BOE could set up very soon but this is not the case. The continents protect the Arctic Ocean. It is not an accident that the peripheral seas that are protected by land freeze better than seas that are more open to warm water intrusions. The Kara Sea is further south than much of the Barents but it will freeze over while the Barents now remains substantially ice free through the winter. This is due to the protection that Novaya Zemlya provides it. The Beaufort, Chukchi and ESS are also further south than the Barents and we see the same thing. We will continue to observe the Arctic Ocean be protected in this manner in a rapidly warming world.

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Re: Ice-free Arctic
« Reply #373 on: April 01, 2018, 07:18:31 PM »
I do believe that BAU (or near BAU) for the remainder of the 21st century (a distinct possibility) could set us up for an eventual year long ice free Arctic Ocean but this will not occur in our lifetimes.
« Last Edit: April 01, 2018, 07:24:04 PM by Shared Humanity »

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Re: Ice-free Arctic
« Reply #374 on: April 01, 2018, 11:50:53 PM »
I personally think that having the arctic ocean ice free year round is possible. Can't say when though...
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Re: Ice-free Arctic
« Reply #375 on: April 02, 2018, 04:33:15 PM »
I do believe that BAU (or near BAU) for the remainder of the 21st century (a distinct possibility) could set us up for an eventual year long ice free Arctic Ocean but this will not occur in our lifetimes.

I concur with both your posts.  The land surrounding much of the Arctic waters offers isolation from warmer ocean waters.  This reduces summer melt and enhanced winter growth.  I doubt that the Arctic will ever become ice-free year round, as the physics of ice formation will remain.  When the first occurrence of a summer ice-free condition occurs is difficult to predict.  While it could happen in my lifetime, I suspect not (unless I reach the century mark).  The longer it takes to reach ice-free conditions, the better chance that humanity will will take the appropriate actions.

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Re: Ice-free Arctic
« Reply #376 on: April 02, 2018, 07:02:55 PM »
I agree, the long polar night will result in some ice formation during the winter, even when the world heats up substantially from today.   Year Long Ice Free (YLIF?) is not credible in our lifetimes.....

Also, what is BAU?

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Re: Ice-free Arctic
« Reply #377 on: April 02, 2018, 08:51:22 PM »
BAU stands for business as usual.  In other words, no significant action to lower CO2 emissions.

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Re: Ice-free Arctic
« Reply #378 on: April 02, 2018, 11:09:43 PM »
Also, what is BAU?
Business As Usual scenario, humanity continuing to burn fossil fuels with no real change in behavior. Same as it does today, more or less. (But with more people and more economic growth)

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Re: Ice-free Arctic
« Reply #379 on: April 02, 2018, 11:53:23 PM »

...
Heat from the Pacific and Atlantic current is already being transported into the Arctic Ocean and if the Arctic Ocean were not as protected as it is from warmer waters, I think an all year long BOE could set up very soon but this is not the case.
...
Part of that protection is the stratification in the arctic ocean. Because of it ice formation doesn't lead to bottom water generation.  Mix up the stratification and have open water then you get bottom water.  Take the surface water and run it down to the bottom more surface water will replace it.  Surface water is on the surface because it has low density.  Cooling it or adding salt makes it denser.  (adding fresh water reduces density)  Overturn the water inside of the CAB and you pull in surface water to replace what was on the surface.


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Re: Ice-free Arctic
« Reply #380 on: April 07, 2018, 04:59:42 AM »
My assumptions justifying thinking the gulf stream will find its way into the arctic ocean.

1. A BOE will let the stratification of the arctic ocean be disrupted by wave action.

2. when the sun sets and things cool off with the stratification a thing of the past you get bottom water production rather than ice.

3. what drives the currents around Greenland and the CAA currently is the Earth's rotation the warmth coming up from the equator (gulf stream) and the large freshwater input from ice melt and run off.

4. it is the cold reduced salinity run off water plus ocean water surface water current that pushes the gulf stream away from the east coat of north America.

The freshwater mixes with surface water, if that becomes bottom water then the surface water needs to be replaced.  The cold water would sink rather than stay on the surface.  So instead of a current coming out of the arctic ocean past Greenland you would have a current going in instead.

No current pushing the gulf stream east.  So it would go north into the arctic ocean.

With 20C water coming into the arctic basin you could see 20C air temps over the water and storms like there was no tomorrow.

Where would you get those 20C waters from? We hardly ever reach 20C in the North Sea even during those exceptionally hot and sunny summers we had in the 90s. And that's like 2000km south of what is considered arctic ocean.

Just wondering.
« Last Edit: April 07, 2018, 05:07:57 AM by Coffee Drinker »

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Re: Ice-free Arctic
« Reply #381 on: April 07, 2018, 03:25:19 PM »
Didn't we see near Med. temps in the McKenzie Delta back in 2012?

There is a lot of shallow shelf waters around the basin and 24/7 of sun over high summer might drive some big temp blooms?

If the rivers flowing into the basin are also coming out of scorched lands too then we might see high temps by mid aug?

Not sure of 20c though?
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Re: Ice-free Arctic
« Reply #382 on: April 07, 2018, 05:06:48 PM »
Didn't we see near Med. temps in the McKenzie Delta back in 2012?

There is a lot of shallow shelf waters around the basin and 24/7 of sun over high summer might drive some big temp blooms?

If the rivers flowing into the basin are also coming out of scorched lands too then we might see high temps by mid aug?

Not sure of 20c though?


Yes.
At an island to the west, whose name escaped me, researchers were taking daily swims in the arctic ocean.
20c may not be high enough.
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Re: Ice-free Arctic
« Reply #383 on: April 13, 2018, 04:34:18 PM »
I've been looking at area recently by each of the Arctic Seas. The question I asked myself was "how many days is each sea ice-free already?". I decided to use the criterion of ice area below 5% (sort-of) of recent years maxima, i.e. in effect a bit stricter than the 1 million km2 used for defining ice-free for the whole Arctic. I also used the NSIDC from their spreadsheet in their sea-ice-tools selection.

I attach three graphs - containing the peripheral seas, the seas composing the CAB, the peripheral seas,and Hudson Bay. Four peripheral seas are at or above 6 months ice-free. None others. Things only really started to happen in the CAB about 12 years ago. The Central Arctic Ocean and the Canadian Archipelago have yet to make an appearance on the graph. The Beaufort Sea made only one appearance - for 14 days in 2012.

A long way to go for an ice-free Arctic even for a day ?

If I am still extant, it will be interesting to see how this changes over the years.

« Last Edit: April 13, 2018, 04:44:22 PM by gerontocrat »
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Re: Ice-free Arctic
« Reply #384 on: April 13, 2018, 05:06:54 PM »
Nice work gerontocrat.

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Re: Ice-free Arctic
« Reply #385 on: April 14, 2018, 12:04:13 AM »
I've been looking at area recently by each of the Arctic Seas. The question I asked myself was "how many days is each sea ice-free already?". I decided to use the criterion of ice area below 5% (sort-of) of recent years maxima, i.e. in effect a bit stricter than the 1 million km2 used for defining ice-free for the whole Arctic. I also used the NSIDC from their spreadsheet in their sea-ice-tools selection.
Very good. I think the results are quite significant, with 2007 being the point where the ongoing changes made themselves apparent.
May I suggest using other criteria as well, besides the 5%. The reasoning behind this is that some of these seas have become seasonally ice free in parts of their geography, while other parts of the same seas are still ice-covered throughout the year. So using thresholds of 15%, and even 50%, could yield interesting results.

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Re: Ice-free Arctic
« Reply #386 on: April 16, 2018, 04:52:05 PM »
<snip, enough already, this is getting repetitive; N.>
« Last Edit: April 16, 2018, 08:21:32 PM by Neven »

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Re: Ice-free Arctic
« Reply #387 on: April 16, 2018, 05:38:25 PM »
<snip; N.>

This is really mean. Name-calling is for weaklings anyway. Just because someone's views do not coincide with your views does not make him an AGW denier. Mind you, the current scientific consensus puts an ice free arctic somewhere between 2040-2100 depending on who you believe. So, you probably have to live quite long to see an ice-free arctic IF you believe scientists. However, if you believe that you know better than scientists than of course anything is possibble.

I do not hink that anyone on this forum is an AGW denier. Still, as there are numerous debates about feedbacks, changes to atmospheric circulation, etc, etc, there can be many equally valid views about arctic ice. The greatest scientists are those who doubt even their own results, and keep questioning their own views all the time. Beware those who have no doubts about their own truth...
« Last Edit: April 16, 2018, 08:21:58 PM by Neven »

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Re: Ice-free Arctic
« Reply #388 on: April 16, 2018, 08:06:56 PM »
"AGW denier daniel"

I also have doubts as to whether the Arctic will ever be entirely ice-free all year round (this century at least) unless all efforts to reduce CO2 emissions and the resulting increased CO2 ppm are entirely fruitless.

I would be fascinated to see how this makes me "AGW denier gerontocrat ", preferably in a series of logical steps from -

a) Doubts about a year long ice-free  Arctic,
to:
b) denial of AGW.

Waiting breathlessly.....
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Re: Ice-free Arctic
« Reply #389 on: April 16, 2018, 09:40:32 PM »
In the long polar night, ice will form. Put me in the camp of not believing that year long ice free will be occurring any time soon.

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Re: Ice-free Arctic
« Reply #390 on: April 16, 2018, 09:43:55 PM »
And how would this planet look like if the arctic would be ice free all year long ?

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Re: Ice-free Arctic
« Reply #391 on: April 16, 2018, 10:08:15 PM »
Less white.  ;)
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Re: Ice-free Arctic
« Reply #392 on: April 16, 2018, 10:10:16 PM »
as we know the temperatures below which ice will form that would make winter temps of around -10C or higher to prevent ice building and even higher where rivers empty into the ocean.

so until we shall see such temperatures in winter i would rather think in centuries than decades, perhaps even millenia because that would make around 20-30C higher themps than we are currently reaching each winter. once ice is in place it will probably take even higher temps and waves to melt during winter time hence again, this is a long long time out.

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Re: Ice-free Arctic
« Reply #393 on: April 16, 2018, 10:39:08 PM »
In the long polar night, ice will form. Put me in the camp of not believing that year long ice free will be occurring any time soon.

The nights are warming faster than the days!

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Re: Ice-free Arctic
« Reply #394 on: April 16, 2018, 11:17:29 PM »
And how would this planet look like if the arctic would be ice free all year long ?
That is the big question. Neven's less white is telling. If the average night time low is -28C and ice free gets you 20 C warmer, and open sea water freezes at -10C Then you have a margin of 2C. Ice at the edges open in the middle.  Stormy enough to mix up the stratification in the Ocean. Overturning in the CAB.

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Re: Ice-free Arctic
« Reply #395 on: April 17, 2018, 02:47:47 AM »
And how would this planet look like if the arctic would be ice free all year long ?
I find this discussion less interesting. An ice-free summer in the arctic is decades away, but an ice-free arctic in winter is at least centuries away, if at all.

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Re: Ice-free Arctic
« Reply #396 on: April 17, 2018, 03:40:40 AM »
Less white.  ;)

Not if you ask bbr2314. ;D

And I'm starting to agree with him. As everyone agreed here, the atmosphere north of 60 will be below freezing in winter regardless of the amount of ice in the ocean. With all that extra water over an ice less Arctic and the extra global water vapor due to global warming it will probably snow at unimaginable levels in some places.

However I'm not at all convinced that snow will last the summer or restore the sea ice in time for another full melt. 
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Re: Ice-free Arctic
« Reply #397 on: April 17, 2018, 08:06:16 AM »
Snow is also an amazingly effective insulator.
Will we have toasty ground and rocks getting warmer each summer as the severe winter cold kept at bay?
Terry

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Re: Ice-free Arctic
« Reply #398 on: April 17, 2018, 12:32:28 PM »
Could be fun exercise to try to calculate if the decreased albedo made by humans when the Arctic goes ice free in summer would be detectable from Alpha Centaurus using the kind of tech planned to send to space (James Webb Telescope, was it). Soon someone might take a note there's something going on on the planet system of the sixth star of the constellation Zigzag (Cassiopeia).
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Re: Ice-free Arctic
« Reply #399 on: April 17, 2018, 01:06:50 PM »
The first few summers we see 'no ice' the opportunity for storms to drive deep overturning of the ocean stratification of the CAB will alter things making refreeze more difficult and very 'stop start' if storms constantly mix our the forming ice and bring up more warm, salty waters?

Late formed , thing ,salty ice will go faster the following summer and allow longer warming/overturning of the ocean.

I would also think we would see deep fog banks insulating the surface from the bitter cold Arctic night above?

During the PETM there must have been mechanisms for retaining heat all winter as we had palms there that need above 50f temps to survive ( along with the crocs!!).

Knowing it has existed, and existed with high temps not just marginal, must bring us pause for thought?
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