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Messages - Hyperion

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1
Arctic sea ice / Re: The 2018 melting season
« on: August 12, 2018, 11:51:02 AM »
Sentinel has some new shots of the Lincoln Sea. Holy smoke, did it melt out fast or what!
Looking at the SST bandits inbound, I suppose its not surprising. Must be chewing the bums outa the glaciers in Greenland, Awful lots meltwater being flushed out the Nares and all round the edges of the basin too.

2
Arctic sea ice / Re: The 2018 melting season
« on: August 10, 2018, 05:19:22 PM »
I've been looking at that area off Siberia that some guys are saying might survive. Is that dirty yellow green look the fires? My Prof sez it's probably just algae.
It sure looks a lot bluer in the bottom one. Which is north of Nares.

https://apps.sentinel-hub.com/sentinel-playground/?source=S2&lat=74.89179996842871&lng=160.19989013671875&zoom=12&preset=8_BATHYMETRIC&layers=B01,B02,B03&maxcc=20&gain=0.9&gamma=1.2&time=2015-01-01%7C2018-08-07&atmFilter=ATMCOR&showDates=false

4
Arctic sea ice / Re: The 2018 melting season
« on: August 07, 2018, 08:52:38 PM »
Doing a 'reality check', I'm zooming in on an area of thick ice.

Arctic ice thickness (CICE), via yesterday's Navy website [I ignore certificate issues.] shows lots of 2 to 4 meter ice in the Lincoln Sea.  (Color scale pasted into image).  WorldView shows the Lincoln Sea to be filled with a loose mélange with some larger floes that I presume are thick (probably 3 meters or more thick). [Scale moved to be within view.] An arrow points to a floe that, in the Sentinel Hub image (note 3 km scale),  is in the lower right corner.  This shows much of the mélange to be floes, some 5 km across or more, but many on the order of 50-500 meters across.  (Arrow points to corner of floe that is in the lower left corner of 200m scaled enlargement.)  These are plenty big enough to be 2 or more meters thick. [Sentinel-hub doesn't go north of this location.]  See the melt ponds on the enlargement.

Even if it is mostly thick floes, there are a lot of floe edges that can chip away (wind-induced bumper-car style destruction) or melt (wave assisted).
Take a closer look at your sentinel images. Those Floes are loosely bound chunks of rotten ice that have been pushed together and poorly glued by freezing meltwater. Some of those chunks may be up to a couple of meters thick but you can see bigholes everywhere with the ocean showing through. Those are not meltponds.

5
Arctic sea ice / Re: The 2018 melting season
« on: July 30, 2018, 02:57:42 AM »
Yes I'm cherry picking but the gfs after the initial thrust of heat reforms a Siberian positive dipole.


This would be a perfect storm of events to cripple the laptev/CAB Atlantic front and finish the ESS off.
Just the high pressure by itself *without* a dipole is bad enough.  Between bottom melt and Insolation that's enough melt potential to strip 4-8CM/day off of existing ice, much of which is under 1M thick at the moment.

As I said earlier, based on what happened in the Kara, without optimal melt conditions, I'd expect the Chukchi to be ice-free, and very large swaths of the Beaufort, ESS and Laptev to be gone by the 3rd week of August.

6
Arctic sea ice / Re: The 2018 melting season
« on: July 30, 2018, 02:07:31 AM »
Bring back Hyperion, we need the full monte. ;)

Today's ecmwf wave and temperature from windy

7
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.

8
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.

9
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.)

10
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.

11
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.

12
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.

13
Arctic sea ice / Re: SMOS
« on: July 20, 2018, 05:02:58 PM »
does the atlantic ocean communicate freely with the other oceans?

--- edit: Misread the question, thought you were asking about the Atlantic Arctic (doh!)... ---

I guess it depends on what you mean by "freely" ... much more so than the Mediterranean, less than e.g. the Southern Ocean.

The Arctic body of water is either an ocean or a sea. Most of the worlds seas (as named) are actually subdivisions of oceans or other, larger seas,, such as e.g. the Norwegian Sea and the Ionic Sea, but the Black, Mediterranean, and the Caribbean seas are more or less cut off from other seas/oceans (and the Caspian totally ...).

Based on size, the Arctic Ocean is properly named as such, being much closer to the next-smallest ocean than the biggest sea. If, on the other hand, a sea was to be defined as having little or restricted communication with other seas or oceans, then the Arctic Sea might be better. But then again, if such a definition was to be adopted, what would happen to the Sargasso sea which lies more or less in the middle of the Atlantic without touching land!

14
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).

15
Arctic sea ice / Re: SMOS
« on: July 20, 2018, 04:34:53 PM »
does the atlantic ocean communicate freely with the other oceans?

16
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.

17
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.

18
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.

19
Arctic sea ice / Re: SMOS
« on: July 20, 2018, 12:11:54 PM »
I get the feeling RikW's comment was missing a  ;)

20
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.

21
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.

22
Arctic sea ice / Re: SMOS
« on: July 19, 2018, 06:23:05 AM »
Thank you both! Very helpful

23
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?


24
Arctic sea ice / Re: SMOS
« on: July 19, 2018, 05:50:09 AM »
can someone upload a link to find the SMOS data?

25
Arctic sea ice / Re: SMOS
« on: July 14, 2018, 10:32:29 PM »
And the 13th.

SMOS is a better way to look at the state of the Arctic instead of extent....

26
Arctic sea ice / Re: The 2018 melting season
« on: July 14, 2018, 04:49:41 PM »
If this is even remotely correct we are in for trouble

27
Arctic sea ice / Re: SMOS
« on: July 13, 2018, 03:20:33 PM »
It measures thickness in a reliable way if there are no melt ponds and/or open water is absent. So underestimation in the summer. Although it gives an indication if melt is happening, because when thickness decreases fast during summer, there are either a lot of melt ponds, a lot of open water between floes or thickness is really decreasing.

So based on the satellite images you can safely state the ice is in a bad condition

Thanks, so to calibrate it's position in the scale of true values, we'd need to check the numbers against other products during winter. Granted currently the compactness is pretty bad according to some other measures so this would underestimate thickness of remaining ice quite a bit. Say 50% open ocean on a grid cell could then mean the SMOS thickness is 50% smaller than the renaining ice on a grid cell? Anyway compactness is low currently. Interesting product this SMOS, looks almost designed to state the precariousness of the Arctic Ice

28
Arctic sea ice / Re: SMOS
« on: July 13, 2018, 03:04:24 PM »
It measures thickness in a reliable way if there are no melt ponds and/or open water is absent. So underestimation in the summer. Although it gives an indication if melt is happening, because when thickness decreases fast during summer, there are either a lot of melt ponds, a lot of open water between floes or thickness is really decreasing.

So based on the satellite images you can safely state the ice is in a bad condition

29
Arctic sea ice / Re: SMOS
« on: July 13, 2018, 02:48:54 PM »
Ah, SMOS, new ice product? What does it measure? Remaining thickness of first-year ice? The numbers are anyway quite a lot off of some of the other products. And they also differ from each other. Not so long ago there was a thickness map that looked like it measured the thickest bits remaining, maybe this does the same for thinnest bits.

30
Arctic sea ice / Re: SMOS
« on: July 13, 2018, 11:35:49 AM »
https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/beaufortictn_nowcast_anim30d.gif

How reliable is this animation? Because if this is true almost all ice outside 80 degree is below 1m, thus doomed. Or there is a lot of open water, which lowers the ice thickness, which also isn't very good news I'd say.

Too bad we have a lot of clouds on Worldview. Any suggestions for layers/overlays to increase the visibility? I've been checking worldview and animated last month for some parts, I can only say for sure that Kara sea is doomed, which isn't a big surprise and I think the beaufort isn't an ice sheet but just a lot of floes, most of them much smaller than I would like.

For example 2 pictures of beaufort/cab 4 days ago, low on clouds, doesn't look that good. I think it's among the worst years for this region around this date (2015 and 2016 beging the other 2 worst years) but I think the 'bad' region extends closer to the pole (but those clouds...)

31
Arctic sea ice / Re: The 2018 melting season
« on: July 10, 2018, 11:02:51 AM »
... We will most probably see an average or even above-average (when compared with the last 10 years) sea ice area at the end of the melting season. We have still in many area a above-average snow cover, we have less melt-ponding and preconditioning than the record years, we have no favorable weather for ice melt... I don't know what you are smoking, but please stop doing that.
1st, you're being rude ("bullshit" and "smoking" parts). Please, stop being rude. Proper science can never be done when people attack each other. 2nd, few posts above even Neven admitted that this season may still end up in top-3 in terms of minimum annual ASI cover, - and i agree. Therefore, your "we will most probably see an average or even above-average" is over-confident to say the least. If Hyperion is going too far one direction, then you're going too far the other.

32
Arctic sea ice / Re: Don't read this thread
« on: July 08, 2018, 02:12:58 AM »
The collapse of the Roman empire took centuries, and I suspect it didn't become a "collapse" until historians began looking at in modern times.

Other than that I totally agree with Ned W after only some three or four years of watching this forum. Every year we get a chorus of doomsayers that think they understand everything so much better than everybody else. Funnily enough, every year the chorus has new members - wonder if the unusually noisome pack of doomsayers this year will still be so cock-sure next year.

On the other hand, the Ice will melt out eventually, and I (and many others apparently) think that the end could be quite sudden. But this year? Nope.

+1 and in addition to that:

a) can't see why there is always so much opposition to everyone who is trying to point out some truth

b) this should not be about who is right but about doing our joint best to gather as much knowledge as possible, this includes errors and extremes at times.

c) there is an actual empire that started to collapse with all and the same ingredients than the late roman, greek and egyptian empire just to name a few. there is a thread on the matter even.

i like this thread no matter if every detail is exactly true and no matter whether we shall see a kind of sudden death within 5 years or in the year 7 or 12 or any other from now. thing is it will happen and trying to be prepared is nothing that should be criticised so much and since none of us knows exactly when and all the details we should just read and learn as much as we can.

as to who can post what, some of us are a bit on the angry side at times (like myself) and again others are constantly exaggerating and in the process damage credibility. two things to learn
beside other things like claiming bragging rights for stating the obvious, that's the real boring
stuff because to see that everyone can search the web, no special skills needed.

a reasonably good prediction and assessment is much braver and difficult to achieve and logically comes along with many errors while even from those errors we can learn if we really want.

33
Arctic sea ice / Re: SMOS
« on: July 07, 2018, 08:18:42 PM »
Not really, as SMOS can't measure thickness in summer

This is one of those common wisdoms that is actually untrue.  SMOS has high uncertainty for thick ice during the summer, underestimating the thickness of thick ice.  Uncertainty for thin ice is much lower.

New methodology has been devised in the processing of SMOS data in recent years, that has reduced the uncertainties and is now providing a useable data set in the summer.

http://meetingorganizer.copernicus.org/EGU2017/EGU2017-4452.pdf

It's obvious that SMOS grossly underestimates sea ice thickness in summer.  Nothing in your link suggests otherwise.  Note that they are talking about determining sea ice concentration from SMOS data in summer, not thickness.

34
Arctic sea ice / Re: SMOS
« on: July 07, 2018, 08:10:05 PM »
That's impressive, Steven.
A +/- 0.68 million km2 suggests a standard deviation of 340 k km2, which would be at the low end of the predictions at SIPN.

Did you consider submitting an entry this year based on this SMOS data ?

https://www.arcus.org/sipn/sea-ice-outlook/2018/june/call

Since SMOS is a unique, new, variable, your contribution would be very much appreciated.

Thanks, Rob.  But since I used only 8 years of data in the regression analysis (2010-2017), I'm not sure how seriously those numbers should be taken.

Actually I have more confidence in NSIDC sea ice concentration as a predictor of the minimum.  That gives an estimate of 5.0 +/- 0.8 million km2 for the NSIDC September extent, as I posted in the poll thread last Sunday.

35
Arctic sea ice / Re: SMOS
« on: July 07, 2018, 08:09:49 AM »
That is consistent with the finding that SMOS in summer correlates well with low Sept extent.

For what it's worth:  using the average number of beige pixels in the SMOS images in June as a predictor of the NSIDC September extent, the estimate for the September 2018 extent would be  4.74 +/- 0.68 million km2  (95% prediction interval). 

That's impressive, Steven.
A +/- 0.68 million km2 suggests a standard deviation of 340 k km2, which would be at the low end of the predictions at SIPN.

Did you consider submitting an entry this year based on this SMOS data ?

https://www.arcus.org/sipn/sea-ice-outlook/2018/june/call

Since SMOS is a unique, new, variable, your contribution would be very much appreciated.

36
Arctic sea ice / Re: SMOS
« on: July 06, 2018, 11:47:42 PM »
30 cm is 1 ft.  So unless it's red or purple it's less than a foot thick.
Not really, as SMOS can't measure thickness in summer

This is one of those common wisdoms that is actually untrue.  SMOS has high uncertainty for thick ice during the summer, underestimating the thickness of thick ice.  Uncertainty for thin ice is much lower.

New methodology has been devised in the processing of SMOS data in recent years, that has reduced the uncertainties and is now providing a useable data set in the summer.

http://meetingorganizer.copernicus.org/EGU2017/EGU2017-4452.pdf

Alfred-Wegener has also been looking at using a synergistic interpolation of SMOS and Cryosat-2 data to reduce uncertainty as SMOS has low uncertainty with thin ice and Cryosat-2 has low uncertainty with thick ice.

https://www.ecmwf.int/sites/default/files/elibrary/2018/17987-merged-sea-ice-thickness-product-complementary-l-band-and-altimetry-information.pdf


37
Arctic sea ice / Re: SMOS
« on: July 06, 2018, 06:05:47 PM »
DMI is still showing most of the pack at over a meter thick.  Visit their website here:  http://polarportal.dk/en/sea-ice-and-icebergs/sea-ice-thickness-and-volume/

US Navy also has most of the pack at over a meter thick:

https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticictn/nowcast/ictn2018070312_2018070400_930_arcticictn.001.gif

You can get their daily maps here:  https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arc_list_arcticictn.html


38
Arctic sea ice / Re: SMOS
« on: July 06, 2018, 02:37:30 PM »
30 cm is 1 ft.  So unless it's red or purple it's less than a foot thick.
Not really, as SMOS can't measure thickness in summer

39
Arctic sea ice / Re: SMOS
« on: July 06, 2018, 01:44:34 PM »
30 cm is 1 ft.  So unless it's red or purple it's less than a foot thick.   


40
Arctic sea ice / Re: SMOS
« on: July 01, 2018, 06:15:11 AM »
Regarding what SMOS means in summer, I found this :

Quote
The emissivity is mainly a function of bulk ice temperature, salinity and thickness. The bulk ice temperature is estimated from surface air parameters of JRA-25 reanalysis data and a zero-dimensional thermodynamic model [3]. The bulk ice salinity is estimated from a sea surface salinity weekly climatology. The sea ice thickness is corrected for the influence of the thickness distribution function to account for the invalid assumption of a uniform plane ice layer [3]. The latter correction leads to an apparent deeper penetration depth than previously reported [1]. We apply no correction for the influence of ice concentration. Thus, one can expect an underestimation of ice thickness when there is open water within the SMOS footprint. We account only for the thermodynamic influence of a parameterized snow layer on the bulk ice temperature but do not account for the direct radiative effect [4].

https://icdc.cen.uni-hamburg.de/1/daten/cryosphere/l3c-smos-sit.html

This suggests that SMOS is affected by open water between and on the ice.
More open water will trigger SMOS to report thin ice.
That means that ice concentration and SMOS in summer should have overlap (and correlate).
Low ice concentration (lots of surface melt) should thus correlate with low SMOS 'thickness' measurements.

That is consistent with the finding that SMOS in summer correlates well with low Sept extent.

41
Arctic sea ice / Re: SMOS
« on: June 30, 2018, 12:01:42 PM »
Is this thread really necessary?

A good question!

Quote
Plus, you do know SMOS is just like any other tool. With all the melting shenanigans going on this year, it probably has a lot of errors.

If memory serves, and much like CryoSat-2, SMOS maps used not to be published during the "melting season".

42
Arctic sea ice / Re: SMOS
« on: June 30, 2018, 11:29:06 AM »
??

Is this thread really necessary? You've already posted the same comment onto the main melting season thread.

And you are specifically talking about 2018 and it's melting season in comparison to past years.

Also "fiddling"??

Plus, you do know SMOS is just like any other tool. With all the melting shenanigans going on this year, it probably has a lot of errors.

It shouldn't be used as a holy grail to support wide scale hypothesis's about the Arctic.

43
Arctic sea ice / Re: The 2018 melting season
« on: June 23, 2018, 04:15:52 PM »
so again and almost on every page there are ongoing discussions (disputes) as to different models. so far so good but for years i try to start a solution oriented deeper discussion about how to resolve this and any approach is mostly discarded with some "what can we do" or "they are great/sufficient" arguments.

again propose to seriously discuss whether the 15% threshold for extent is still contemporary, considering the fact that we are not looking at a homogeneous ice sheet but highly fractured and somehow perforated ice cover that often remains above 15% but way below the 100% as what they are counted as far as extent is concerned.

sooner or later one has to at least consider to change methods/parameters of measurement to keep up with real world scenarios, or do we really not care if once the ice mass is cut in half an well spread across the arctic to see the ice extent as the same like when it was double the ice but in one single homogenous sheet?

my point is that i believe that many discussions are caused by different interpretations and prioritizing of input and to adapt to new facts could get us rid of many times seeing the same thing differently from different "angles" so to say.

i hope i was able to make myself understood in the way that i'm not seeking to criticize but to take away some unnecessary disputes from the discussions.

IMO extent as it has always been (measured) should not be a holy cow.

since i'm not a scientist i'm not the one to seriously propose specifics bot for the sake of not only moaning but also contributing ideas, i would ask to consider to raise the extent threshold to something between 30 and 50% because if there is less than half of an area covered with ice it's hard to understand why this should count as 100% extent.

this is just one example, there are other factors that undergo heavy changes in the last few years, one is humidity and cloud cover as compared to dry cloudless conditions over vast periods in the past. etc.

44
Arctic sea ice / Re: The 2018 melting season
« on: June 14, 2018, 02:05:58 PM »
... Fresh snow has a very high albedo (reflects 95% of solar radiation) so might delay ice melt once the sun rises.  Thick snow may 'hide' melt ponds delaying their absorbing most of the solar radiation.  These would be positive feedbacks (positive here being 'good for the ice').   But snow may have negative feedbacks as well:  clouds (especially low clouds) in the winter will reduce heat loss to space (Paul showed how recent winters have been rather warmer than it used to be). ...
A request: while what i quoted is true per se, can we all stick with the standard terminology for feedbacks, which is "positive" for any feedback which amplifies the base process, and "negative" for any feedback which slows down the base process. This logic will persist, i am sure, since it's scientifically sound and always applicable, while "positive as in "good"" is subjective; so, using them the way Tor used them in the quote above - will breed more confusion for some, i think...

45
Arctic sea ice / Re: The 2018 melting season
« on: June 13, 2018, 01:34:56 PM »
this morning when i was looking at : https://ads.nipr.ac.jp/vishop/#/extent

i first was annoyed but then had to laugh loudly because it's a good day as far as once again the value of extent numbers at this time of the year has been negatively proven:

a) almost the entire arctic is aroun or above zero

b) parts of the ice cover are hit with temps way above melting temps and in places above 30C

c) ice is thin and mobile and the winter was warm

d) there have been extraordinarily strong winds recently and rain throwing water on the surface.

and now the models want to make us believe that zero ice has been melting yesterday ?

a big joke is the only non-offensive word that comes to my mind, and no wonder that some
question the expenses (i'm not but some are) it's similarly ridiculous like the millions of euros expensive weather forecasts in times when skies are neither blue or overcast and it's not that easy ;)

this is probably due to the 15% threshold which each year causes issues, perhaps we better start to count only zero or close to zero ice agains non-totally ice free to avoid such ups and downs, both often not justified.

where does the 15% threshold come from, is it arbitrary or does it have a solid foundation?

the above mentioned measuring of blue against white or anything that is not totally blue/black i mean seriously being an alternative to those complicated and at times contradictory algorithms that fail over and over again and each failure is feeding deniers who can point at such ridiculous numbers to "QUASI" make their point and cut funding.

i'm sure that some won't like this but this is my opinion and it's about seeking maximum accuracy and clarity as opposed to complicated and well paid models that so often can't keep up with their promises.

those who have another opinion are welcome to tell me why, i'm listening, this is not meant to be the only valid opinion, hence convince me where i'm wrong in your opinion but with reason, not with bias or trouble to get out of the comfort zone ;)

finally it is a miracle that they (the models) don't try to tell us that there was more freezing than melt LOL  ???

46
Arctic sea ice / Re: The 2018 melting season
« on: June 10, 2018, 01:58:39 AM »
June 9th with IR overlay from the 272.8-273.4K bucket (-0.35C - 0.25C) to the 292.9-293.5K bucket:



Image link: https://i.imgur.com/JBObPzi.gif
Worldview link: https://tinyurl.com/yb6kf9vn

47
Arctic sea ice / Re: The 2018 melting season
« on: June 09, 2018, 03:08:11 PM »
This Earther journalist is paying attention:

Quote
...

“The downward intrusion of this polar vortex intensified [the] storm,” Zhang told Earther via email.
...
I mentioned the discovery of polar vortex' behaviour well matching equations which describe traffic jams, couple pages ago or so. When it's stuck, part of it goes "other ways", much like (some) cars do when trying to circumvent jammed area through any kinds of small roads around the jam. If the jam persists, more and more cars will try to "go around" it. Means, such storms may repeat in numbers frequently, one after another, if/when vortex gets seriously "jammed".

48
Arctic sea ice / Re: The 2018 melting season
« on: June 08, 2018, 10:20:49 PM »
More concern to me is moderate high pressure ridge setting up in the Pacific sector, and the strong import of warm air between the ridge and this low.  I see strong sunshine and surface melting kicking off from Laptev to Chukchi/Beaufort.

Absolutely agreed. There's an extreme amount of warm air advection in this region followed by a stagnant block that will cook the area for week(s).

Here's the entire t=-72,384 run of GFS to hammer the point home. This is going to be disastrous for Siberian permafrost and ice.


49
Arctic sea ice / Re: The 2018 melting season
« on: June 05, 2018, 10:08:38 PM »
While not the main weather event at the moment, the weather that swept in from far eastern Siberia over the Chukchi and Beaufort had the effect of disrupting our four favorite radar wavelengths for a couple of days.

There are two Ascat satellites A and B imaging 12 hours apart, making it possible to intercalate them to get slightly smoother image motion. Below, the upper part and elbow of the CAA stringer in the Beaufort-Chukchi are disappearing from view from June 3rd on. The shorter wavelength imagery often has an unwanted weather overlay but Ascat has been largely immune to artifacts for the last ten months.

That's unfortunate since the constituent floes have been trackable since late September. Ascat looks at roughness, more pronounced in MYI; the storm may have had the effect of melting off the rough edges  which makes them less reflective and so darker and not in good contrast with surrounding FYI. Alternatively, the old floes may come back into view as the weather system passes through.

50
Arctic sea ice / Re: The 2018 melting season
« on: June 05, 2018, 07:46:22 PM »
While surface ice has been advected west up the Alaskan coast for months by winds, the silt is just spreading out, indicating no current even at continental shelf depths.

The silt is also accumulating heat rapidly. Above freezing values are shaded in 0.6C increments starting at -0.3C - 0.3C bucket. The hottest regions are currently around 4C. Models are showing ice getting transported into this region in the D4-D8 range due to actions of the upcoming Arctic cyclone.


(June 4th worldview).


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