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Messages - AvantGuardian

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1
Arctic sea ice / Re: The 2018 melting season
« on: August 04, 2018, 09:09:00 PM »
Update on Mercator 0m, 34m and 92m salinity, mar21-aug4. 5.5MB, every other day, click to run
http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20180321/20180804/2/2


edit:confusing animation removed

2
Arctic sea ice / Re: The 2018 melting season
« on: August 04, 2018, 08:19:00 PM »
On world view the clear skies reveal the ice has darkened substantially essentially everywhere

clear skies?

for me this is not clear skies until someone is able to explain the definition of clear skies that differs from "cloud free" that evades me.

the image is from today and it has been that way for a long time while cloud free spots change on a daily basis of course

Not sure where that image is from but it's not accurate.

This is the last three days.  Anywhere with a red or orangish red tint is ice.  And or snow.

This is about as could free as it gets.  There is fog in the cab thanks to tremendous WAA but for August this is impressive.

image is from windy ECMF while GFS looks a bit better but similar (no clear skies)

so since we're interested to find the real thing, what or who says which is accureate ?

after all satellite images don't look that clear skies to me as well,  i mean clear skies like "no clouds"

i've been looking at the posted images and there were clearly structures white in white that hint at cloud cover, willing and ready to learn more since until now i always thought that windy is a reliable source with even various sources included as well as that i was able to distinguish clouds from clear skies.

your image does look artificial colored,means it's processed, i prefer unprocessed photos when possible, everything else goes a bit under "paper accepts everything" if you know what i mean.

however i'm asking, not saying, perhaps there are factors i'm not aware of that i can use in the future to get a better view.

thanks

3
Arctic sea ice / Re: The 2018 melting season
« on: August 04, 2018, 08:16:14 PM »
Discussions of ice free arctic in winter is something for the paleoclimate studies of the Paleocene-Eocene equable climate......
What say you, about ice free Arctic in September.....August.... July, October, June, May, April, November? Or are those discussions for.... futurologists, yet unborn?

They are discussions for other threads unless you would like to discuss the likelihood of ice free conditions extending into the fall for this season.

Hehe....I am not discounting that as a possibility, but no one else seems to entertain that as conceivable.

And no, I am not predicting it...just saying that when the ice decides to go away it won't matter if it is daytime or nighttime.

4
Arctic sea ice / Re: The 2018 melting season
« on: August 04, 2018, 07:43:40 PM »
On world view the clear skies reveal the ice has darkened substantially essentially everywhere

clear skies?

for me this is not clear skies until someone is able to explain the definition of clear skies that differs from "cloud free" that evades me.

the image is from today and it has been that way for a long time while cloud free spots change on a daily basis of course

Not sure where that image is from but it's not accurate.

This is the last three days.  Anywhere with a red or orangish red tint is ice.  And or snow.

This is about as could free as it gets.  There is fog in the cab thanks to tremendous WAA but for August this is impressive.

5
Arctic sea ice / Re: The 2018 melting season
« on: August 04, 2018, 07:39:49 PM »
Discussions of ice free arctic in winter is something for the paleoclimate studies of the Paleocene-Eocene equable climate......
What say you, about ice free Arctic in September.....August.... July, October, June, May, April, November? Or are those discussions for.... futurologists, yet unborn?

They are discussions for other threads unless you would like to discuss the likelihood of ice free conditions extending into the fall for this season.

6
Arctic sea ice / Re: SMOS
« on: July 22, 2018, 10:40:14 PM »
I updated my pixel-counting calculations with SMOS images that were quoted in the topmost post of this thread.  First, I counted the number of beige pixels for each daily SMOS image for July 2010-2018:




Clearly 2013 and 2014 stand out.  But in general the number of beige pixels in July is quite small. 

As an alternative, I included more pixel colors from the color legend of the SMOS images.  More specifically, I lumped together all the beige, purple, red and yellow pixels of the SMOS images in the pixel counting algorithm:





Average number of pixels for the first 21 days of July:


7
Arctic sea ice / Re: SMOS
« on: July 22, 2018, 09:54:50 PM »
It near as dammit is a blue ocean event already Neven. I bet my left nut that anything near the periphery, extending now to a Chukchi to Barents strip right across the pole where meltponding is being reported is actually open water, and satellites being fooled by wave action.
And what I cannot stand is bullying. Which is what you supported.

As said, if there's a BOE event this year (it's already practically there according to you), I will apologize. Conversely, if there's no BOE, you'll get banned from this forum.
So already now we know for sure there will be no BOE this year :)

8
Arctic sea ice / Re: SMOS
« on: July 22, 2018, 08:14:05 PM »
Neven, that will improve the signal to noise ratio around here.

9
Arctic sea ice / Re: SMOS
« on: July 22, 2018, 06:30:29 PM »
Generally, in the Arctic the density gradient is controlled by salinity not temperature. The light fresh water floats above the saline layers. Thus the process you propose generally does not happen in the Arctic.

"Under the floe a similar but salinity driven process works as warmer saltier water below is exchanged and turned over as it gives energy to the ice and is freshened by melt in a non uniform process."

10
Arctic sea ice / Re: SMOS
« on: July 22, 2018, 11:38:36 AM »
16 to 21 July. Apart from the major disintegration of the pac-ruski quadrant, major changes appear to be compaction into the CAA garlic press and Svalbard region killing grounds.

11
Arctic sea ice / Re: SMOS
« on: July 22, 2018, 04:06:52 AM »
When the ice is a fractured and mobile pack of porous honeycombed ice, as per today's arctic, there's a lot more complexity than a one dimensional conduction calculation can give good approximations from s-wing.
Like the thermo karst effect. The densest fresh water is 4-6 degC. So it is quite normal for the top of waterlogged cavities to be at zero degrees, or even frozen over,  whilst deeper down there is warmer water burrowing deeper. You might call this subsurface micro-meltponding

Under the floe a similar but salinity driven process works as warmer saltier water below is exchanged and turned over as it gives energy to the ice and is freshened by melt in a non uniform process. One can even envisage outward flow of freshened melt from the edges of floes drawing up warmer more saline stuff from below in the middle. Exactly like the process tunneling under the ice shelves of Antarctica and Greenland.
Algal growth into the porous bottom of the ice absorbs solar energy, metabolic heat and antifreeze secretionsthat lower the melting point still further, increases porosity, and of course warm salty water rises.
These convection processes should vastly increase the   thermal transfer through the average 1m ice.

And then there is radiative energy transfered in microwave and ultraviolet spectra that ice is near transparent to.

12
Arctic sea ice / Re: SMOS
« on: July 22, 2018, 02:44:12 AM »
Bottom melt happens primarily near the edges of floes, and the heat source is from radiation absorbed by the open water between the floes.  The onset is generally quite late in the season, but because of the huge thermal mass of the ocean, it can continue even after atmospheric temperatures have dropped below freezing at the transition from summer to autumn.

Anything other than the above is a mere detail in the small decimal places. This forum used to know stuff like this!

13
Arctic sea ice / Re: SMOS
« on: July 22, 2018, 01:32:53 AM »

I would think there is a gradient, the base of the ice is fixed at >-1.8°C and the top of the ice at <0°C which would match a salinity gradient through the ice. If you heat the basal water (insolation, pushing the ice over warm sea) then the ice melts from the bottom.

If you heat the ice from the top, insolation, warm air, warm rain, then you might be in a thermodynamic environment to cause bottom melt. I could easily see water on top of the ice causing bottom melt, as it freezes and releases heat of fusion and then ice conducting that energy to the base. Perhaps that is one mechanism by which ice becomes fresher as it ages. In reality, at equlibrium, the ice surface should be 'dry', it refreezes at 0°C causing bottom melt.

14
Arctic sea ice / Re: SMOS
« on: July 22, 2018, 01:06:37 AM »
OT but 'Atlas' carried the sky on his shoulders, actually inside his head he was a navigator in the days before maps and atlas's curiously. Without complete star knowledge sailors got lost.

15
Arctic sea ice / Re: SMOS
« on: July 21, 2018, 11:13:18 PM »
Agree, Fish, that there are other processes - that you have given - that can cause a lot of bottom melt even when the top of the ice is dry.

The above discussion relates specifically to heat conduction down through the ice when the top is heated by warm winds.

Parenthetically, there are also a couple of other issues that work against lots of heat transfer by that mechanism: air can carry only very little heat per unit volume - orders of magnitude less than water, and the thermal coupling to the ice will usually be poor. (Water vapour in the air helps though.)

16
Arctic sea ice / Re: SMOS
« on: July 21, 2018, 05:05:23 PM »
After the snow on top melts, light passes through the ice warming the water below the ice. That's physically possible when the sun is at a high enough angle. There's also advection of Atlantic water into the Arctic ocean. There's also the transport of ice over Beaufort & Chukchi sea summer water. We don't need to invent non-physical processes to get bottom melting. Sometimes that will happen when the top surface isn't melting, but generally not in July.

17
Arctic sea ice / Re: SMOS
« on: July 21, 2018, 02:49:20 PM »
This magical bottom-only melt arises because "Ice conducts heat better than water", and so it will conduct the atmospheric energy through to the water under the ice, allowing the ice to melt from the bottom, but not the top.  This is drivel.  Heat cannot of itself pass from one body to a hotter body. i.e. if the ice is conducting heat downwards, then the top of the ice is hotter than the bottom, so the top will melt first.

Commenting in this discussion, this is my understanding of the situation.

Hyperion is technically correct - this situation is possible under some circumstances.

The quote above is correct that the top will be 'hotter' than the bottom, because that is where the heat is coming from.

However, it is incorrect in claiming that means the top will always melt first. The reason is the presence of salt at the bottom, but not at the top, which lowers the melting point at the bottom.

E.g the top will melt at 0 degrees C if there's no salt, but the bottom may melt at -1.8 degrees C at a reasonable salinity for sea water.

So the situation of bottom melt in Arctic sea ice with heat carried from a dry top is theoretically possible.

In practice, on the other hand, I suspect that such a scenario is presumably unlikely to make a big contribution to the overall melt.

The reason is that the thermal conductivity of ice is not all that good: it's around 2.2 W/(mK). So there is going to be a non-negligible temperature gradient in order to carry a non-negligible flow of heat down through the ice.

Consider this scenario, chosen to be a type of threshold case:
1 meter thick ice
0 degrees at the top
-1.8 degrees at the bottom
With both top and bottom at the threshold temperature for melting.

Linearizing for simplicity, the thermal gradient is 1.8 degrees/meter.

This implies a heat flow of ~2.2 W/(m.K) x 1.8 K/m = 4 W/m^2

The heat of melting of ice is 334 kJ/kg (same reference as above).

So rate of melting is ~4 J/(s.m^2) x / (334,000 J/kg x 900 kg/m^3) ~ 1.3e-8 m/s
(presuming a density of 900 J/kg)

A month is ~pi x 10^7s / 12 (using a useful mnemonic for approximate number of seconds in a year)

So that rate of melting would be 1.3e-8 m/s x pi x 10^7 / 12 ~ 3.5e-2 m/month = 3.5 cm/month.

So this threshold situation would be a bottom melt rate of only 3 or 4 cm per month.

If the bottom melt rate is:
a) Above this, then the top will be wet;
b) Below this, then the top can be dry even when the bottom is melting from heat carried downwards.

This is obviously a simplified situation - it is not rigorous - and is for ice that is 1 meter thick.
(If the ice is thinner\thicker then the melt rate can be more\less, in approximately inverse proportion to the thickness.)


But it illustrates the general point that ice dry at the top cannot be carrying much heat down to be melting the bottom.

SUMMARY:

Consider a situation for the Arctic sea ice where the heat to melt ice is coming from above. Then:

1) Bottom melt can only be fast, or even moderately fast, if the top is wet; and

2) The maximum bottom melt rate where a dry top is even possible (where the heat comes from above, & holding to some sort of long term equilibrium) is only of order a few cm/month.

So bottom melt with a dry top but still using heat arriving through the ice and from the top, while physically possible, is likely not the dominant scenario for Arctic sea ice.

18
Arctic sea ice / Re: SMOS
« on: July 21, 2018, 02:39:48 PM »
The second sentence in the Wikipedia article on Arctic Ocean:
Quote
The International Hydrographic Organization (IHO) recognizes it as an ocean, although some oceanographers call it the Arctic Mediterranean Sea or simply the Arctic Sea, classifying it a mediterranean sea or an estuary of the Atlantic Ocean.[2][3]


Quote
...
2."'Arctic Ocean' - Encyclopædia Britannica". Retrieved 2012-07-02. "As an approximation, the Arctic Ocean may be regarded as an estuary of the Atlantic Ocean."

I was surprised too...

19
Arctic sea ice / Re: SMOS
« on: July 21, 2018, 11:02:10 AM »
They are just that, ramblings, which is why I mostly don't bother to respond.

20
Arctic sea ice / Re: SMOS
« on: July 21, 2018, 10:45:55 AM »
...the factual claims you keep making are large, strange and without evidence, and I see it as my duty to point this out before this forum becomes a fantasy free-for-all.
Quite. As far as I can tell from Hyperion's ramblings, warm air currents are supposed to magically cause bottom melt without top melt, so the ice surface stays dry.  A contention that's trivially disproved with a large dry martini and a hairdryer.
Actually proven with a handful of salt, some ice cubes and some water to float them, while you use your hairdryer Peter. Its how everyone did freezers before electric ones.

21
Arctic sea ice / Re: SMOS
« on: July 21, 2018, 10:38:50 AM »
...the factual claims you keep making are large, strange and without evidence, and I see it as my duty to point this out before this forum becomes a fantasy free-for-all.
Quite. As far as I can tell from Hyperion's ramblings, warm air currents are supposed to magically cause bottom melt without top melt, so the ice surface stays dry.  A contention that's trivially disproved with a large dry martini and a hairdryer.

This magical bottom-only melt arises because "Ice conducts heat better than water", and so it will conduct the atmospheric energy through to the water under the ice, allowing the ice to melt from the bottom, but not the top.  This is drivel.  Heat cannot of itself pass from one body to a hotter body. i.e. if the ice is conducting heat downwards, then the top of the ice is hotter than the bottom, so the top will melt first.

22
Arctic sea ice / Re: SMOS
« on: July 21, 2018, 10:28:56 AM »
I don't think the Arctic Ocean can be called a "deep brackish tidal lagoon or estuary" at 14 million square kilometers, an average depth in excess of 1 km, maximum depth 4.5 kilometers.

My point in pointing this out is that at only 2.7% of the earths surface and less than half of that in annual insolation. Insolation is no where near as important as the energy coming in and out from surrounding landmasses.

What you did say was "Insolation directly on the estuary is not significant in a thin, young ice regime" which is a baseless claim, i.e. without evidence. It also goes against the laws of physics,  since a "thin young ice regime" would be more affected by direct sunlight than thicker ice.

Now you make another claim, based on percentages, i.e. that insolation over the Arctic Ocean is nowhere near as important as the energy coming in and out from surrounding landmasses. Again this is without evidence, and seems to go against the consensus. But it depends on circumstances - if the Arctic Ocean is covered with clouds and strong low-pressure areas, sunlight will not reach the ice but warm air will be sucked in from surrounding landmasses.

But that has nothing to do with 2.7% or any other figure you might want to put forward.

As for me criticizing your post, the "estuary" remarks were what we adults call "sarcasm" and the factual claims you keep making are large, strange and without evidence, and I see it as my duty to point this out before this forum becomes a fantasy free-for-all.

23
Arctic sea ice / Re: SMOS
« on: July 21, 2018, 07:59:06 AM »
Really there is one world ocean. With Antarctica in the middle of it. Since for most of the last few million years, the Arctic has been an icelocked pond with almost no communication with the world ocean, its probably quite fair to call it a deep brackish tidal lagoon or estuary. My point in pointing this out is that at only 2.7% of the earths surface and less than half of that in annual insolation. Insolation is no where near as important as the energy coming in and out from surrounding landmasses.
I wrote an extensive post about this on the melting thread.

24
Arctic sea ice / Re: SMOS
« on: July 20, 2018, 06:19:11 PM »
Pluto it is not - no demotion on the horizon. It has been, is, and will be an ocean, until it is ice-free for at least most of the year. Then perhaps someone will say - it is now totally Atlantified (horrible word) - so is part of the Atlantic Ocean.

Atlantisized?

The Atlantic is of course named after the giant Atlas who holds the world on his shoulders (cf. the mythical "Atlantis" in ancient Greek is Ἀτλαντὶς νῆσος (Atlantic nisos, literally the Island of Atlas).

So to follow tradition (cf. Sargasso Sea), once blue ocean is reached, we could rename the Arctic Ocean the Atlasso Sea, being a part (or sea) of the Atlantic after beging Atlassoed (presumably with one hand) by Atlas.

25
Arctic sea ice / Re: SMOS
« on: July 20, 2018, 06:08:21 PM »
Pluto it is not - no demotion on the horizon. It has been, is, and will be an ocean, until it is ice-free for at least most of the year. Then perhaps someone will say - it is now totally Atlantified (horrible word) - so is part of the Atlantic Ocean.

Atlantisized?

26
Arctic sea ice / Re: SMOS
« on: July 20, 2018, 05:18:00 PM »
If the Arctic was demoted to a sea - what becomes of the seas of the Arctic Ocean? Chukchi, Beaufort, ESS etc - ponds?

Pluto it is not - no demotion on the horizon. It has been, is, and will be an ocean, until it is ice-free for at least most of the year. Then perhaps someone will say - it is now totally Atlantified (horrible word) - so is part of the Atlantic Ocean.

27
Arctic sea ice / Re: SMOS
« on: July 20, 2018, 05:07:10 PM »
does the atlantic ocean communicate freely with the other oceans?
I think Indian ocean provides most of the surface waters, intermediate waters and northern Atlantic bottom waters come mostly from interaction with Arctic ocean and some northern bottom water and all of southern bottom water come from interaction through acc and southern ocean. Mediterranean is mostly a water sink and would dry up if Gibraltar and Suez were blocked. Simplified.

28
Arctic sea ice / Re: SMOS
« on: July 20, 2018, 04:56:49 PM »
does the atlantic ocean communicate freely with the other oceans?

The Arctic for one, the Southern Ocean for two, the Indian Ocean for three (saw it 35 years ago at the tip of Africa - amazing how you could see the difference and the boundary between the two).

29
Arctic sea ice / Re: SMOS
« on: July 20, 2018, 04:34:53 PM »
does the atlantic ocean communicate freely with the other oceans?

30
Arctic sea ice / Re: SMOS
« on: July 20, 2018, 04:18:51 PM »
Oh! The "Arctic Estuary" is not on any known maps. An estuary is defined as the tidal mouth of a large river and is obviously not a useful label for the Arctic Ocean which does in deed cover 2.7% of the earth's surface.

Well, this 2012 paper does analogize the Arctic Ocean to an estuary:

https://link.springer.com/article/10.1007/s12237-010-9357-3

But it also calls the Arctic a "beta ocean," in contrast to other "alpha oceans".  Which seems ... not so nice.

I think the "estuary" metaphor is not meant to be taken seriously. The Arctic Ocean is more than 14 times bigger then the largest sea (the Mediterranean) but 10 times smaller then the largest ocean (the Pacific).

The Arctic Ocean is 64% of the size of the Southern Ocean, and 5 times smaller than the Atlantic. So based on size alone, the Arctic Ocean seems to be properly named.

On the other hand, it is mostly enclosed by land while the other Oceans communicate more or less freely with each other with large "ocean-border" areas.

31
Arctic sea ice / Re: SMOS
« on: July 20, 2018, 04:11:52 PM »
<snip, no endless quoting, please; N.>

Binntho, this is the third time you have appeared to be deliberately wasting forum space and my time by claiming that I am making baseless claims, and demanding evidence belligerently while quoting me providing that evidence in the same post. Please read Wikipedia's article on the Arctic ocean for yourself. And the references provided there as to why oceanographers describe it as an estuary. Which is a body of lower and often  stratified salinity water where one or more riverine freshwater entries mix with ocean water before entering the ocean through a constricted exit.

<snip, stop playing the victim, please; N.>

32
Arctic sea ice / Re: SMOS
« on: July 20, 2018, 04:04:11 PM »
Oh! The "Arctic Estuary" is not on any known maps. An estuary is defined as the tidal mouth of a large river and is obviously not a useful label for the Arctic Ocean which does in deed cover 2.7% of the earth's surface.

Well, this 2012 paper does analogize the Arctic Ocean to an estuary:

https://link.springer.com/article/10.1007/s12237-010-9357-3

But it also calls the Arctic a "beta ocean," in contrast to other "alpha oceans".  Which seems ... not so nice.

33
Arctic sea ice / Re: SMOS
« on: July 20, 2018, 12:12:23 PM »
You really should expect the majority of the ice surface in the estuary to be dry in the current regime Tor.

What estuary are we talking about here?  The areas that seem to be dry in the SMOS image are not over any known estuaries.

And with the consistent high atmospheric energy input over the whole estuary surface.

What estuary?

The salinity differential bottom to top. Its a bottom melt surface freeze paradigm we are in.

Again, where? On the "dry" part of SMOS? And by "bottom melt surface freeze paradigm" do you mean that the surface is freezing as a consequence of bottom melt, or that some third factor is causing both? Any evidence?

Remember the Arctic Estuary is only 2.7% of the earths surface.

Oh! The "Arctic Estuary" is not on any known maps. An estuary is defined as the tidal mouth of a large river and is obviously not a useful label for the Arctic Ocean which does in deed cover 2.7% of the earth's surface.

Insolation directly on the estuary is not significant in a thin, young ice regime.

But no entrainment? Baseless claim without evidence and flouting the laws of physics.

34
Arctic sea ice / Re: SMOS
« on: July 20, 2018, 12:11:54 PM »
I get the feeling RikW's comment was missing a  ;)

35
Arctic sea ice / Re: SMOS
« on: July 20, 2018, 12:09:05 PM »
So massive thickening in the CAB, so I presume melt season somehow ended already?
It's not thickening.  SMOS doesn't measure thickness accurately during the melt season.
(This could be posted as a followup to every other post in this thread, so let's just assume it was)

36
Arctic sea ice / Re: SMOS
« on: July 20, 2018, 10:42:33 AM »
You really should expect the majority of the ice surface in the estuary to be dry in the current regime Tor. Ice conducts heat better than water. And with the consistent high atmospheric energy input over the whole estuary surface. The salinity differential bottom to top. Its a bottom melt surface freeze paradigm we are in. Remember the Arctic Estuary is only 2.7% of the earths surface. Insolation directly on the estuary is not significant in a thin, young ice regime.

Wikipedia:
The Arctic Ocean is the smallest and shallowest of the world's five major oceans.[1] The International Hydrographic Organization (IHO) recognizes it as an ocean, although some oceanographers call it the Arctic Mediterranean Sea or simply the Arctic Sea, classifying it a mediterranean sea or an estuary of the Atlantic Ocean.[2][

37
Arctic sea ice / Re: SMOS
« on: July 19, 2018, 11:38:57 PM »
from July 1 (above)
Quote
SMOS is affected by open water between and on the ice.
I think what is useful is the beige areas which show 'dry' ice.  I presume this is local freeze, new snow or compaction.

38
Arctic sea ice / Re: SMOS
« on: July 19, 2018, 11:02:38 PM »
Those were 16,17,18,19 1000hpa winds and temperature.
This is today.

39
Arctic sea ice / Re: SMOS
« on: July 19, 2018, 10:42:19 PM »
So massive thickening in the CAB, so I presume melt season somehow ended already?

i think its just the ice compacting.
Yes. There has been strong winds and heat coming in on the Pacific side for a few days and a ring of small cyclones around the Russian coast and a larger one in Chukchi-Beaufort.
The big area of blue at the eastern end of the Chukchi is where the remnant Beaufort circulation is. That's quickly going poof. So where the compaction is happening isn't at all great for the ice surviving. Its been shifted to where warm salty Atlantic water is available at shallow depth and its also vulnerable to wave mixing and breaking from the Atlantic.
And lined up for the Fram, Nares, and CAA export and kill zone.

40
Arctic sea ice / Re: SMOS
« on: July 19, 2018, 09:32:04 PM »
So massive thickening in the CAB, so I presume melt season somehow ended already?

i think its just the ice compacting.

41
Arctic sea ice / Re: SMOS
« on: July 19, 2018, 09:08:38 PM »
So massive thickening in the CAB, so I presume melt season somehow ended already?

42
Arctic sea ice / Re: SMOS
« on: July 19, 2018, 07:19:03 AM »
The maps are here:
https://seaice.uni-bremen.de/data/smos/png/

I've used the ones ending in _hvnorth_rfi_l1c.png, though I don't know why they differ from the _hvnorth_l1c.png ones, nor do I know if there is any reason to prefer one over the other.

By inspection, they look similar but not identical. I'm guessing the "rfi" ones have some extra processing but that's just a guess. Does anyone know?
The rfi version has the radio frequency interference from high powered radar systems processed out of it. I've been posting the plain unadulterated version. Call me quirky, but I prefer raw data feeds as little processed as possible. It seems to be outside the pack that gets any and only occasional effect anyway. And I guess I kind of like seeing when and where these probably mainly military radar systems are being used. ::)

The last seven days. With a funky fade between frames and a little enlargement, seems to help visually track the changes.

43
Arctic sea ice / Re: SMOS
« on: July 19, 2018, 06:23:05 AM »
Thank you both! Very helpful

44
Arctic sea ice / Re: SMOS
« on: July 19, 2018, 06:07:17 AM »
The maps are here:
https://seaice.uni-bremen.de/data/smos/png/

I've used the ones ending in _hvnorth_rfi_l1c.png, though I don't know why they differ from the _hvnorth_l1c.png ones, nor do I know if there is any reason to prefer one over the other.

By inspection, they look similar but not identical. I'm guessing the "rfi" ones have some extra processing but that's just a guess. Does anyone know?


45
Arctic sea ice / Re: SMOS
« on: July 19, 2018, 06:01:44 AM »

46
Arctic sea ice / Re: SMOS
« on: July 19, 2018, 05:50:09 AM »
can someone upload a link to find the SMOS data?

47
Arctic sea ice / Re: The 2018 melting season
« on: July 17, 2018, 10:16:31 PM »
What is protecting the ice is the cooler fresh water layer that is causing the warm Atlantic Water current to move below it.  The stratification is keeping the warm current from acting upon the ice.

There is enough heat in the mid level layer to melt out the ice several times over.  should that stratification break down and allow mixing, as has now happened in the Barents, 'Atlantification' would take place throughout the Arctic.

Apparently the counter-cyclonic movement of the Beaufort Gyre is the only thing preventing the fresh water layer from flushing into the north Atlantic.

Should it slow and reverse as it used to do regularly prior to 2006, that warm water would come to the surface and obliterate the ice.

 https://forum.arctic-sea-ice.net/index.php/topic,2349.msg163554.html#new   
It already has slowed right down and purged Cid. As discussed earlier. And the Beaufort lid freshwater store has been misleadingly reported as having increased in recent years in published papers by defining freshwater as the amount of water below 34psu. In the early 2000s it was around 22psu in the Beaufort surface layer. Now 29psu or above.
The winds waves and currents coming up between Greenland and Svalbard in the last month have even entrained the melt and beaufort lid coming out through the CAA and Labrador sea over the last month, and now are mixing it into the Atlantic inflow. This will allow the Atlantic inflow to stay near surface in the mixing zone, matching its salinity with the Pacific inflow and Atlantic surface water layers.
I think people should keep their speculation about this seasons end result to the threads st up for that purpose. It's driving away the more informed commentary with all the yabber based on irrelevant extent, making out the ice is in recovery or that its a slow melt year. This thread is supposed to be for recording the detailed situation as it happens. Is it not?

48
Arctic sea ice / Re: The 2018 melting season
« on: July 17, 2018, 09:52:06 PM »
I agree with you Ice Shield. For the last few years, especially during the last pronounced El Nino, I thought we were going to see a massive drop in the ice extent and each year I have been completely wrong.  I am very amazed at the resilience ice pack post 2012. Even the ocean currents in the arctic are much cooler than I had expected to see. I suppose the nonstop clouds and fog are doing an ample job at protecting the ice. Though, and I'm sure I'm totally wrong here, part of me wonders if the water up north is as cold as it is due to much more bottom melt than anticipated.

That said, the pack is certainly not in great shape and like what it once was. While I think we will hobble along in the same pattern and we won't see an ice-free year until at least the 2030's, I think that one year with ideal conditions conducive to melting, like 2012, will devastate the pack and the true extent of the broken flows will become apparent and more pronounced. But for now I will sit and watch and try to figure out wtf is going on with our climate.
We are having a lot of meltwater and melting floes dispersed out into the periphery and out of the basin by the anticlockwise cyclonic rotation. This also causes ekman suction which draws up saltier waters from below, enhancing bottom melting, increasing warm subsurface inflows from the pacific and atlantic, and reducing the temperature of the water that the ice is melting in.
This creates a feedback increasing atmospheric heat transfer in at low level, by enhancing the temperature difference between the land that has more low level heat and moisture being drawn into the basin over its coasts by the cyclonic activity. And the cooler than normal ice kill zones nearby, with the ice being flung out into them. The extensive fog and low cloud is not just trapping outgoing heat, but is a symptom of very large energy input into the ice and rapid melting .
Latest US Navy Beaufort animation.seems to need a click to animate.

49
Arctic sea ice / Re: The 2018 melting season
« on: July 16, 2018, 01:52:06 AM »



Quote

The polar cell has in effect collapsed, and a Ferrell circulation is in effect with low level incoming winds feeding lows, and their upper level outflows feeding high pressure systems covering the central north Pacific and Atlantic Oceans.

So, we have low pressure above the Arctic and a high pressure system in the Atlantic and the central north Pacific? We do have those every summer. What is the big deal? Attached is the average MSLP for 1979-2015 July.

Its not so usual for the entire ocean basins of the whole world to be solidly covered, by one giant high pressure system each, for over a month Cid. Except the South Pacific which is wider and it hasn't been so consistent. There's a big difference between long term means and the size and persistence of these features.

50
Arctic sea ice / Re: The 2018 melting season
« on: July 16, 2018, 01:40:49 AM »
Some worthy views through the fog of the state of the ice in the deep central basin. Better from Aqua modis than Terra today
Remember each pixel is 250m. So you won't see gaps that small. And most of what look like large rounded cohesive floes are loosely glued together rubble. Thats the mottled grey look if you zoom in.
Even the relatively solid looking patch towards the CAA from the pole has that look. And its in an area that has been compacted by the recent ring of cylones around the outside of the basin.
Wideview,
North Beaufort, 80+nth, near the pole of inaccessibility,
Svalbard to pole on left bottom corner.
Compressed patch off the CAA

Click to enlarge.

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