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Messages - F.Tnioli

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51
Arctic sea ice / Re: The 2020 melting season
« on: May 09, 2020, 05:03:41 AM »
Thank you for the better description of SMOS cutoff for Cryosat, and other SMOS limitations. This is what should have been posted in the first place if you find the original poster was not accurate enough. Clarify, explain, bring more info, make better wording. And do not hint the cutoff is to hide something or that somebody was lying because they used inaccurate terminology.

Back to what this topic is for - bringing information, data, analysis and commentary about the Arctic sea ice melting season that is just beginning in earnest.
When it seems someone is not accurate enough, i exactly offer a description which i deem better one. Like i just did above, - and there is no need to thank me for it really, such a small thing. "Not accurate enough" at some point gets "so off the target it doesn't look they are even trying" though.

I see it's time i walk outta that door - stay silent at least for fairly long while. Especially seeing you saying i anyhow stated that "someone's lying because they used inaccurate terminology". Which, i never did. Nothing even remotely close. I take this as a gentle hint that it's time i say good bye - what else can it be, seeing it's from you, not some stranger.

I'll keep reading now and then and of course, i wish you best of luck keeping things orderly and neat. Cheers!

52
Arctic sea ice / Re: The 2020 melting season
« on: May 09, 2020, 12:28:07 AM »
...
uni-bremen are kind enough to continue to provide the service as other information may be inferred from the data...at the user's discretion
"Service" from "stopped" SMOS?

This is a recurring problem of this page: terms. "SMOS stopped" does not equal "does not produce meaningful results". "Other information may be inferred" does not equal "does not produce meaningful information". "Melt ponds confuse sensors" does not equal "wetness of the surface confuses sensors".

Since we're talking about, i'll note that from what i know, SMOS growing error in April has little to nothing to do with "melt ponds" nor with "wetness" of ice surface itself. Instead, the main problem is increasing presense of fog and thin clouds [Yu and Rothrock 1996]. This does not mean April and May SMOS data is "meaningless", however. It means different, more complex approaches are needed in treating raw data to have still useful and precise enough results. Specific data products having a cut at April 15 do not nesessarily mean all data products are stopped. The picture i gave as an example - is a kind of a data product itself, and is indeed useful for easy eye-balling of thin ice right now, in May.

Please note, i am not asking to explain every little detail in this topic. I ask to use non-contradicting terms. Like, instead of "melt ponds confuse sensors" - say, for example, "technology limitations disallow reliable total Arctic ice volume measurement after mid-April based on those sensors". Like, instead of "SMOS stopped" say "SMOS measurements stop being used for calculating total ice volume mid-spring due to growing measurement errors which currently we're unable to remove". Etc.

If we'd be failing to avoid "contradicting per common sense of a non-scientist" statements here - even when such contradictions are in error de-facto - then what exactly this topic is for?

53
Arctic sea ice / Re: The 2020 melting season
« on: May 08, 2020, 09:42:54 PM »
...
Thus, CryoSat-2 thicknesses stop at April 30 and SMOS (respectively CryoSat-2/SMOS) thicknesses stop at April 15.

No.




54
Arctic sea ice / Re: The 2020 melting season
« on: May 08, 2020, 05:53:27 PM »
F. Tnioli, a gentle warning: I will not tolerate hints of lies, conspiracies and the like on this thread. There is a perfectly good explanation, and lying by ice scientists is not it.
In addition, I've requested that DMI volume discussions take place in the appropriate thread.
Will you tolerate this thread saying "there are no melt ponds in April" and also saying "no data from CryoSat-2 for 2nd half of April because meltponds confuse sensors"?

If the answer is "yes", i'll see myself to the door voluntarily. If the answer is "no", then i ask to forgive me for probably inappropriate way used to describe the problem.

DMI's realiability or lack of - was not discussed. I merely mentioned couple things about it as relevant to discussing "melt ponds in late April confused CryoSat-2 sensors" line, which line is the thing i discussed. DMI graphs are welcomed here for what - to ignore them? I am confused. For now i'll simply avoid doing _any_ mention of DMI results / data, then.

In any case, please feel free to snip this and/or previous post of mine any way you deem good for this topic, up to and including complete removal. I will never hold any grudge towards you, Oren, no matter how much my opinion may differ from yours at times.

55
Arctic sea ice / Re: The 2020 melting season
« on: May 08, 2020, 04:54:31 PM »
here's the latest CryoSat-2/SMOS "measured" volume:

http://GreatWhiteCon.info/2020/05/facts-about-the-arctic-in-may-2020/

The graph stops in mid April, since melt ponds confuse the sensors
The figure's interesting to see alright, thanks for sharing! But here's one side note about it.

What melt ponds? Like was said above in the topic, there are no significant melt ponds in April in Arctic. Or were there? So, it sure looks like someone's lying: either those who said "no meltponds there", or whomever said "after mid-April melt ponds confused the sensors". Simple, right?

My guts say, it ain't melt ponds. DMI shows major volume drop in volume exactly in 2nd half of April. "Coincedence"? Hardly. And may i remind us all that DMI volume is "based on calculations using DMI's operational ocean and sea ice model HYCOM-CICE". Models don't get confused by melt ponds, eh. But people who see sensors showing volume going down when it shouldn't be going down even half as much - they have a reason to worry whether sensors are malfunctioning (or something gone wrong between sensors and actual collected data), and thus just make up an excuse and stop sharing data. Since they could be affraid at the time that collected data could be significantly wrong due to some technical malfunction or somesuch.

P.S. By the way, as of today DMI volume starts to dip down again. Already. Maybe CryoSat-2 now sees things which are way too wild to publish and the actual reason is not mainly about "melt ponds confuses sensors"? Confusions like this can sure happen aplenty when unexpected occurs. Please, let us try to find even more ways to estimate what's going on, gentlemen. It'd help.

56
Arctic sea ice / Re: The 2020 melting season
« on: May 06, 2020, 10:00:04 AM »
It looks like last week has been good for the ice. Volume has increased again.
Great news! I think, next week won't have unusually rapid total volume drop yet, too. But after ~15th, can be another unprecedented drop, it seems. Aluminium says about those 10...14 days, few posts above. And of course this whole deal about high pressure, too. I checked some air temps and winds couple days ago over ice in southern Greenland, a bit above surface, and it was up to 10C moist air going over rather big area there, which while not extremely abnormal then and there in the past - is still significantly higher than in previous seasons. Etc.

One usual feature of most kinds of collapsing systems - is increased volatility. This rapid drop last week is unusual, and now this rebound is also unusual. Thus, i think maybe we'll get another unusual drop by the end of May, possibly ending the month below 20k km3 in DMI numbers. I wonder how much, exactly, this "collapsing system is more volatile than usual" could apply to sea ice / melting season, though.

57
Arctic sea ice / Re: The 2020 melting season
« on: May 04, 2020, 09:23:26 PM »
As if 1050+ is not enough to be one helluva big story, though. Especially for May. Lots of places would see it as highest-ever in well over a century of observations, like, for example, Iceland.

58
Arctic sea ice / Re: The 2020 melting season
« on: May 04, 2020, 07:47:55 AM »
2-3 weeks is what i expect, Friv. Not 1 month. Cleaner air, you know. Instruments confirm, overall Arctic.

59
Arctic sea ice / Re: The 2020 melting season
« on: May 03, 2020, 03:14:55 PM »
... Not sure what kind of weather pattern can cause this and what the probability is for it to remain sustained for a long period. ...
Why, we can see it alright. Quite a pattern indeed.

Day 68 is early March, and we had "positively persistent, persistently positive" AO at the time, as conviniently reported exactly in early March on this page.

So i took a quick look and it seems we had up to some 25 km/h winds exactly "between Pole and Greenland" at day ~68, surface level:



Importantly, this was very wide wind field, as you can see. Looks like ~25% of CAB ice was pushed sough and then south-east by those winds, which push mounts to huge pressure, i'd imagine, given how large area this wind was working against. Which usually doesn't do much in winter because ice holds structurally. But i think this time, it snapped under the pressure near that day 68. It'd probably still remain mostly stuck, but ~4 days later, this started (and lasted for a few days):



Given your numbers, which mean some ~0,5 km/h drift speed average for those 37 days, and given this wind speed - that drift does not surprise me the least.

I also checked same (or very close if no data for exactly March 8th is available) all the way back to 2014, and not a single year had anything similar even to 1st picture, normally it's smaller much more wavy winds much within CAB itself; and especially nothing even remotely close to the 2nd picture.

P.S. It was also then and there we had that massive ozone hole present. I read most stratospheric ozone was gone. The gas absorbs / traps IR really well, so when there is little of it and no sunlight to speak of, big temperature gradients form up. Ergo, stronger winds. Which we exactly see per above.

60
Arctic sea ice / Re: The 2020 melting season
« on: May 02, 2020, 02:50:42 PM »
... Seals do NOT crawl onto the ice where polar bears "can hunt them"!
...
They do, see v=zNO0kxTClYo on YT. However, i'm much more interested to know what you think about my above hypothesis of sunlight actually adding some melt water whenever irregular ice/snow surfaces are present. I agree with others when they say it'd be highly unusual to see melt ponds forming now, but then i also see highly (pun intended) unusual temperatures in March on Atlantic and Siberian sides, too:



I wish we could just ask good gents on Polarstern to go out and check if snow/ice is any wet when it's sunny around the ship. I know satellite sensors can pick up liquid water even when it's not in distinct ponds, but mixed with snow on top of ice. Could be one big part of those "strangely little ice" images posted above, me thinks.

61
Arctic sea ice / Re: The 2020 melting season
« on: May 01, 2020, 11:06:36 PM »
Me neither, Neill. ;) Perhaps it rained, perhaps moisture, perhaps clouds. Let's see if we hear something from the Polarstern.
...
This photograph, i believe, was created from Polarstern's bridge ~3 days ago, 28th April:



Can you see the bear? Anyhow, from the accompanying note posted at nasa.gov, we can read that the bear is, quote, "standing behind Met City near a small lead, likely waiting for a seal". Earlier in the note, we also read that bear, quote, "... sat near a small crack in the ice for almost two hours, likely waiting for a seal to surface".  Seals, i understand, would need open water to come onto the ice, where polar bears could hunt them. So, it seems there are some areas of open water per the above - and it looks like at least some of such openings do not freeze up any much for ~2 hours. I don't think bears are that stupid to spend some hour+ hunting a piece of any significantly thick ice, are they?

Much more importantly, however, is shape of sea ice which above picture presents. As one can see, ice in this particular area is abundantly uneven. With Sun being low over horizon for the time being, this creates really long shadows, clearly visible on the picture. Yet surfaces which are _creating_ those shadows - are often nearly vertical, and thus they absorb lots of sunlight. I think those surfaces are wet, - now that air is much cleaner than in previous melt season, very long path it takes sun rays to go through the athmosphere (because Sun is so low yet) does not deplete energy of sunlight anywhere close as it did previous seasons. Like was mentioned couple pages ago, one can easily see from Finland shore all the way to Estonia now - visibility is _times_ better. Same story would mean times higher W/m2 hitting those "bumps" on sea ice, per above picture - and wet them up good deal even while overall 2m tempeatures may be at -10C or even lower.

And we clearly see the area was quite well lit as of 3 days ago, too.

If someone has any better explanation than above, then please share.

62
Arctic sea ice / Re: The 2020 melting season
« on: April 30, 2020, 10:41:41 PM »
Hmmm... 🤔
500 km3 of ice gone in last 10 days of April, eh. If this what's going on, then things melt as if it was last 10 days of May, not April. Like lengthening melt season by 1 month, sort of. For BoE, "extra 3 weeks" should suffice if one would do some silly numbers on a napkin based on what we saw in 2019. Could be we're starting to see even more melt power than anticipated per some above concerns, Pinatubo and all. Please keep 'em volume graphics coming if possible once a week. Few more weeks should tell us helluva lot of story already if this pace would continue.

63
Arctic sea ice / Re: The 2020 melting season
« on: April 29, 2020, 02:33:37 PM »
...
It will be interesting to see if area drops below 2016 over the next few days, which considering how much vulnerable ice there is in peripheral seas, shouldn't be hard.
Interesting indeed, but needs to be observed in conjunction with data about ongoing cloud cover (or lack of) over said peripheral seas. There are two factors we expect to play a big role in the process - vulnerable state of ice and clean air, and yet they both are minimized when/where there is no sunlight present over any given peripheral sea, roughly speaking. Thus i'd say it's not just "if" area drops or not, - it's "if" area drops in those seas which are any well soaked in direct sunlight.

And to me it's also very interesting to see if we'll have more such areas than usual. Current weather / vortex effects of course overrides, but there is now that general effect of way less nuclei in clouds - so bigger water droplets / snowflakes, means precipitation should deplete clouds faster.

64
Arctic sea ice / Re: The 2020 melting season
« on: April 28, 2020, 01:33:01 PM »
...
Would it be more informative if I changed how many years the current year is compared to. Maybe post-2012 instead?
...
Yes, it would be. 2013 and onwards is a whole new league of its own.

65
Arctic sea ice / Re: The 2020 melting season
« on: April 28, 2020, 10:31:38 AM »
...
* Personally-charged comments and slights of honor should be avoided (even when justified...), ...
Gentlemen - everyone! I ask us all to note the above bold / large (my enhancement) words and always remember them. At _all_ times.

I thank you, Oren, for putting it this way. This will allow us all to remain professional, here. Please strike down anyone violating this particular part - "even when _justified_" - without mercy. I think this is the greatest part you just did, for this topic!

66
Arctic sea ice / Re: The 2020 melting season
« on: April 28, 2020, 10:25:46 AM »
We have seen a massive drop in aerosols and the conversation preceded this post further discussing the impact of contrails.

I think Freegrass is correct. The aerosol problem this year is unprecedented. A page or two back, or it may have been another thread, someone posted that we contribute roughly 8 Pinatubos of SO2 a year to the atmosphere. What will the impact be of one less Pinatubo a year? Or two? Or three? Or even four? The best case is we have two "reverse Pinatubos" the worst, is probably three or four. That is a recipe for absolute catastrophe in the Arctic, especially when you compound it with the impact of contrails / etc.
You probably refer to this post: https://forum.arctic-sea-ice.net/index.php/topic,3017.msg261429.html#msg261429 , in particular its paragraph following "3." one. And while "absolute catastrophe" is not likely to happen - i deem "absolute catastrophe" being the state when Arctic ocean top layers stay much above freezing point 24/365, like it was in the past when crocodiles lived there, - i concur that this melt season is likely to mark the beginning of the shift which will eventually lead to such a state. Huge thermal capacity, you know. Will take more than one or two summers to get there.

Obviously, melt ponding will be our early indicator of how dire a situation this melt season is likely to end up being. Extra attention to melt ponds, with perhaps finding new methods to quantify melt ponding better than we were able before, would very much help.

67
Science / Re: Contrails & artificial clouds
« on: April 27, 2020, 04:17:22 PM »
Recent conversations in the general melting thread have brought up the subject of contrails. And in particular what effect would reduced air travel have on global and/or Arctic temperatures.

I couldnt find a more recent thread specifically on contrails and didnt want to mix it up with the aerosol thread which is a bigger topic.

Most of the literature I see out there say that aviation-induced radiative forcings (CO2, nitrogen oxides (NOx) and contrail/cirrus cloud formation) have a net warming effect. . NOx creates ozone and destroys methane and is a net warmer. As are the contrails and resultant cloud formation which trap radiation escaping from the Earth.

It's not all one way traffic though and this study in Nature found that contrail cirrus cause a significant decrease in natural cloudiness, which partly offsets their warming effect.

https://www.nature.com/articles/nclimate1068

So in reply to F.Tnioli post in the melting thread, would the reduced aircraft over the Arctic have a slight cooling effect overall ?
The way i see it, whenever insolation is close or at 24/7, incoming radiation is much higher than what Earth surface is able to "bleed back" to near-Earth space. Thus sunny places like equator are hot, ain't it. So during polar day, clearer sky - in particular, less contrails, - is definitely major warming of Arctic surface layers. Much of the summer, as we all know, insolation in Arctic is higher than even at the equator. High albedo slows the melt, of course, and it's a kind of balance which can and will be affected.

To me it's in general that simple: contrails are a sort of insulation, and as such it works both ways. I.e., slows down both cooling and warming: whichever would naturally happen given no contrails are present - would still happen, just slower: the more contrails, the slower temperature change will happen on average, if we speak the surface of Earth, that is.

As since for most of this winter we had "normal" amount of contrails over Arctic (let's not forget they don't entirely dissipate same day flights stop happening, far from), there was "slower/less cooling than it'd be without contrails" for freezing season, thus resulting in less ice thickness, weaker ice, warmer ice temperature on average, etc; but now with contrails gone, this "weak freezing season" - weak as is in compare to the old days, pre-1980s, - will be followed by "stronger (than recent years - with plenty contrails)" melt season.

So, before someone drops a vial with some coronavirus 2.0 - please tell 'em to wait about doing it all the way till NH summer, right? This way next "no contrails" season will happen in NH winter, clearer skies = more freezing. Then at least it'd be somewhat good for the ice outta next outbreak of the kind, eh...




68
Arctic sea ice / Re: The 2020 melting season
« on: April 27, 2020, 11:52:24 AM »
Some opportunities are better not attempted too early, though. Unintended consequences of premature experimentation can be quite upsetting. :·)

<Please avoid posting OT YouTube videos in the main thread, though I appreciate the humor. O>

69
Arctic sea ice / Re: The 2020 melting season
« on: April 27, 2020, 10:28:15 AM »
I took a bit of time to verify if my above concern about jet contrails now mostly missing from Arctic sky is of any practical significance, and what i found - is yet worse than i throught it'd be. Namely, i found that:

- during recent years, there was continuous jet liner air traffic over Arctic on the scope of many hundreds flights per day by only US air lines, and most likely well over a thousand flights total if to include non-US international air lines flying this North Route, as they call over-Arctic airways;

- but now, ICAO says that in April 2020, global international passenger capacity "so far" suffered 91 percent reduction.

And obviously, most of remaining - for now - 9% of international flights are not between usual sides of trans-Arctic flights: Europe and US are most affected by the virus, so quite nobody would be eager to accept lots of flights from those parts - not now, nor for (at least) a few months forward.

So, this is fully comparable to the 9/11 case of almost whole US jet liner fleet grounded for three days after 9/11, described in that BBC transcript i linked in my earlier post: "During the grounding the temperature range jumped by over a degree Celsius. DR DAVID TRAVIS: This was the largest temperature swing of this magnitude in the last thirty years". Except this time, it ain't for three days, it's for months, and apparently well past May. Which means 0/0 night time. No cooling, only heating up the surface whenever not cloudy.

I tend to value practical measurements of this kind higher than modelling, and so it seems to me absense of jet contrails alone will bring in - over weeks of 24/7 sunshine unobstracted by contrails - _several_ degrees C increase to surface temperatures.

Can't see how anything less can be. With recent years at times quite walking the edge, it seems this time BOE is quite at the door, and possibly with a big bang. If i miss something crucial, please tell. I'd want to...

70
Arctic sea ice / Re: The 2020 melting season
« on: April 25, 2020, 01:12:07 PM »
...
Do you have any stats to back up  this  ? Re cyclones.
I don't, but i did not look for, either. Was just general consideration, which i think is quite obvious: when it's some 10%...15% of sunlight normally much absorved by aerosols, "normally" means with recent-years-typical amount of fuel burning by mankind, - we'll have that much more heat mostly added to troposphere, and cyclones are driven by athmospheric heat. Substract from it, and less "of" cyclones will be around: less number as well as less intensity.

Important also: "less" means "less than would otherwise happen", and with ever-growing GHGs, the general trend is to _more_ of cyclones as years go by. So less aerosols will make it "less than would happen with both normal aerosol content and with normal GHG growth", which does not nesessarily mean "less than in recent years", since GHG growth is ongoing process.

It would surely be very interesting to see how many and how strong cyclones in the Arctic would end up happening, but obviously we're not yet at the point in time when this could be measured / quantified. This is a talk for the end of this melting season - about estimating cyclones' number, strength and effects on sea ice.

The above point about less aerosols present in the air remains game-changing despite the uncertainty about "absolute" number and strength of cyclones / cloudy days during this season, however, because higher actual insolation at the surface - i.e. few percent more sunlight reaching the ice directly, - will still produce greater melt "per sunny day" than in recent years. Especially with less jet contrails directly over the Arctic as per less jet liners crossing the Arctic back and forth, as was usual in exactly recent years. The effect is relatively small "directly", but multiplicated with further albedo feedback, of course - few percent faster melt produces few percent darker surfaces on average, which then add ever growing further extra melt into the picture.

71
Arctic sea ice / Re: The 2020 melting season
« on: April 24, 2020, 07:36:14 PM »
Thank you for the chart grixm. It's worrying to see this year leading in that metric. Though it does appear that recent years bunch together come summer.
I join the tanks to grixm for the graph; much appreciated, and definitely timely per concerns further in this post.

I apologize for somewhat lengthy remainder of this post, but i think this is way too important; like, 2020's "must know" thing for the melting season (and for lots of other things too).

This is in response to the reference of "recent years" by Davidsd. This year is much different from recent years, and much more so than lots of people here could probably imagine.

1. China stopped most of its transport and industries for a fair while, and lots of it - half, give or take - are not back even now. This is now being followed globally: fuel burning by mankind is decreasing by the day, as reflected by oil prices;

2. This means less aerosols in the athmosphere, to say the least. Plenty cities in China were observing the stars clearly for the 1st time in decades, so strong was reduction in air pollution there. The normal effect of global dimming at the surface is quite massive on average over continents, too - over 10%, at places well over 15%, as was discovered by both pan-evaporation measurements, other methods and eventually multi-national 4-year INDOEX measurement effort (some details freely available here: http://www.bbc.co.uk/sn/tvradio/programmes/horizon/dimming_trans.shtml ). In the same piece one can also find summary of findings about direct effect of absense of jet contrails, which was found to be much bigger and more rapid in practice than anticipated.

3. As a result, right now (as well as progressively stronger during last couple months as the situation develops) - significantly less sunlight gets "caught" by aerosols before it reaches surface, which means less of cyclones (direct consequence of comparatively less heat content in the air), so more shiny days on average scale, and faster melt ponding / top melt in the local scale. So far, most of GHG effect - in the Arctic as well as around the globe - was negated by aerosols in this way, and lots of it still is, but the changes are big enough to already be a game-changer as far as ASI melting season is concerned as a whole.

To understand the scale and importance of those effects, it is enough to remind oneself that industrial activities since the industrial revolution have injected nearly 5000 Tg of SO2 into the athmosphere, with recent years being ~7...10 Tg/year - and that famous Pinatubo eruption, responsible for significant cooling of whole Earth's climate, released only ~1 Tg of SO2. Thus, even "modest" 10% cut of aerosol emissions by mankind can produce changes comparable in magnitude to Pinatubo eruption - except not to cooling, but to warming the climate. Further details about how aerosols work and plenty references for great number of good papers - can be seen here: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015RG000511 .

That same piece also describes timescales relevant for aerosols' lifetime in the athmosphere, which depending on type, size and source of a particle will vary from some hours to some months - with everything tropospheric leaning towards much shorter lifetimes (days to few weeks at best, usually) as precipitation washes 'em down to surface.

Same piece also mentions the following processes, to give a short quote here (by bold):

"In the stratosphere, strong zonal winds lead to fast homogenization of aerosols and tracers in the zonal direction, while vertical and meridional transport is controlled by the BDC [Holton et al., 1995; Butchart, 2014]. The BDC results from the breaking of upward propagating waves in the stratosphere that lead to a diabatic residual circulation [Holton, 2004]. The residual circulation is characterized by ascent over the tropics, poleward motion in the extratropics, and subsidence over the high latitudes, in particular over the winter polar vortex, ...".

So, with rather big uncertainties about how yet worse microbiological situation will become in the following weeks and months, but with rather big certainty that lots of intercontinental jet flights over the Arctic are not happening and won't be happening any time soon, i can easily conclude that "recent years" are not a predictor of anything, now.

72
Arctic sea ice / Re: The 2019/2020 freezing season
« on: March 02, 2020, 12:16:26 PM »
...
I think to put it in context Hefaistos, you need to think not necessarily about what's happening now, but where conditions will be in 3-4 weeks.

What is happening is setup, much like how much running room you have leading up to a broad jump.  By losing snow this early, and picking up what are modest but still significant amounts of solar energy means that considerably more energy will
(1) ... be captured directly at Arctic latitudes
(2) ... be available early in the melt season
(3) ... not be required for/buffered by local phase change (e.g. melting snow locally)
(4) ... indirectly permit more transport of heat to the Arctic from lower latitudes. (primarily via
          increased moisture)
...

That's why lots of bare ground at high latitudes is concerning, even before the equinox.
Right. I can also add (5) to the list: less snow cover "buffer" to resist melting season start.

By this, i mean that when some place say south of Finland has 0 cm snow cover or say 10 cm snow cover - while the average for the place is say 1 meter of snow cover, by March 1st, - then very little to zero heat is needed to have the place's surface to start absorbing sunlight as soon as the Sun starts to put any substantial amount of it in. When such a place is say few millions km2, this will warm up cyclone-scaled air masses in a matter of couple weeks or so; while normally, they'd remain on top of (slowly melting, but still largely white) snow-covered land. Means most outcoming radiation is simply reflected, i.e. short-wave; while in this "new normal", lots of outcoming radiation is long-wave (infra-red), thus greenhouse gases further add in even more heat to the air.

There certainly are some situations in Arctic and next to it when further increase of temperatures is slowed / halted by some strong negative feedbacks, but "little / no snow late winter and early spring" is one opposite case; positive feedbacks seem to strongly prevail.

73
Arctic sea ice / Re: The 2019/2020 freezing season
« on: February 26, 2020, 12:14:38 PM »
...
Northern hemisphere snow distribution is uneven - modest positive anomalies across parts of Siberia and N. America, but significant regions at high latitude in Europe that are currently snow-free with daily increasing heat.
...
My bold. I said it a while ago about "no snow cover during late winter triggers massive albedo feedback", meaning by this significant insolation in February, March and April hitting dark Earth surface instead of white snow. Which brings in - as it stands right now - truly massive extra heat into the system where and when this heat is not supposed to be. Above posted temperature anomalies for large area south of Scandinavia and large parts of Siberia - are mind-boggling to me.

I foresee highly unusual melting season as a result. In particular, i expect great number of strong cyclones entering the Arctic and some, possibly, forming in it much earlier and stronger than ever before. Russian Far East and much of Canada remaining cold while Atlantic side warming up at an accelerating pace (low albedo plus rapidly increasing effective insolation as Sun gets higher over horizon for longer times in more and more places) - will create huge air masses of wildly different temperature, which will sooner or later interact with quite predictable result. Not good for ice, i guess...

74
Arctic sea ice / Re: The 2019/2020 freezing season
« on: January 14, 2020, 02:14:46 PM »
Those ponds, together with "Last weeks 7-day hindsight means GIF (anomalies)" posted by Blumencraft just few posts above, confirm one big suspicion i had for this freezing season: namely, the huge winter mode shift for Arctic and subarctic regions. Which shift is more heat and moisture in the system causing more clouds remaining for much of the winter, which clouds then dramatically slow down winter-time heat loss from both the surface and lower athmosphere. Which slowing further massively extends duration and scale of "thickly clouded" areas - a runaway process.

Obviously, any prolonged periods of massively dwarfed heat-loss process in Arctic and adjucent regions - will have significant impact on following melting season(s), but there is yet one much more serious implication: the "albedo connection" as one may perhaps call it. The warmer things are, the less places are snow-covered by the time insolation starts to be a thing again (and the less snowcover's thickness / brightness is there in places which still retain some snowcover, too). Just like ArcticMelt2 just mentioned: "when the sun comes up", which for sub-arctic regions is already pretty much "now" or "very soon".

Right about now, we have much of the Arctic cloudy (good bye, "polar desert", eh), and even some parts of it - between Iceland and UK/Scandinavia - getting few millimeters of rain. If those cyclones would keep coming same way, then together with seriously positive SST anomalies around Scandinavia and all along US eastern coast - then i wouldn't be surprised to see Atlantic side of the Arctic going blue much much earlier than ever before, later this year.

75
Arctic sea ice / Re: The 2019 melting season
« on: September 20, 2019, 01:34:16 PM »
Sam, multi-year dynamics are off-topic here as long as discussing them does not lead to anyhow better understanding of the 2019 melting season. The _topic_ is named "The 2019 melting season", and thus any discussion which does not and/or can not allow to gain knowledge about this one single melting season, in here - is off-topic by definition. This does not anyhow reduce such discussion's own value, of course. The term "off-topic" merely indicates the discussion, however valuable, is not supposed to happen in this particular topic, nothing more and nothing else.

That said, there are indeed some subjects which, despite being off-topic, may be allowed to be discussed in this topic by the board's administration, to some finite length. The one Sark so originally touched - is probably among them. Importance and obvious relation to this melting season are among probable reasons for it to be. However, please always remember that the more off-topic discussion we'd do here, the less compact and "handy" the topic becomes for great many people who come to it for information specifically about the melting season itself. It is, you see, much about respect to other people to limit off-topic discussion here quite much, even if and when there would be good reasons to have it.

IMHO.

76
Arctic sea ice / Re: The 2019 melting season
« on: September 18, 2019, 02:12:48 PM »
I believe water is densest at several degrees above freezing.
3.98°C, yes, and it's nothing to believe into. Few more details. It's one measurable constant and anyone with even basic thermometer, freezer, any kind of a large (5+ L) hermetically sealable bottle, and not entirely flat surface of their brain - can measure it themselves in home conditions, if they so wish... :)

77
Arctic sea ice / Re: The 2019 melting season
« on: September 12, 2019, 02:00:39 PM »
Excellent photos, Jim. Thanks for posting. Always highly useful to see the ice this way - "close and personal".

P.S. and this is 100% extent right there all around, right? Yeah. Figures.

78
Arctic sea ice / Re: The 2019 melting season
« on: September 12, 2019, 01:43:44 PM »
...
On that note, how's that multi-year ice doing in 2019?
It's doing exceptionally well: practically all of it is in sea ice's heaven now. Gone to better world, it is. No more suffering from all the greenhouse effect, bottom melt, rains and melt ponds all over it. RIP, MYI.

NASA was kind enough to present 1984-2019 animation about it - see yourself, in which amount of ice 4+ years old is practically zero by July 2019.

79
Arctic sea ice / Re: The 2019 melting season
« on: September 09, 2019, 02:54:50 PM »
If the mercator model is correct slush dispersion doesn't significantly affect SST yet. Depending on the weather, extent may follow 2018's slush path (brown) to meet 2012 (yellow).
amsr2-uhh overlaid at 60% transparency onto mercator SST, aug1-sep6
wipneus regional extent, CAB, sep6
piomas percentage of maximum by year, CAB, 2011-2019
edit:forgot scale
I have a feeling that that PIOMASS percentage-of-maximum graph has too little space on the right side, with - was it? - day 260 being the limit. I mean, my gut says _this_ year the minimum in terms of that particular metric could perhaps happen well past day 260. I wonder if you feel anyhow similar, sir.

80
Arctic sea ice / Re: The 2019 melting season
« on: August 23, 2019, 11:36:59 PM »
... 969 hPa, and in 5 days, if the forecast holds, Svalbard will be hit hard.
I had a feeling it'll be strengthening as we get closer to the date. Plenty energy in the system. Tends to do that. Let's see if it'll end up even lower.

GAC 2019 on the horizon now, no joke. 2007 + 5 = 2012, 2012 + 4 = 2016, 2016 + 3 = 2019 may well end up quite a complete pattern yet, eh. If so, one wonders what will be happening after +2 = 2021 and +1 = 2022. Every year GAC year afterwards? Heck. I wouldn't be much surprised at all...

81
Arctic sea ice / Re: The 2019 melting season
« on: August 23, 2019, 04:52:22 PM »
...
Re: The O/T.
...
Enough O/T, gentlemen, please? And PETM, i've sent you a PM about it, and i eagerly await your reply there. If you'll want to add anybody else to that PM conversation - please feel free. But here, we must stay on this season's details without any significantly big O/T deviations, as you certainly know. Cheers!

82
Arctic sea ice / Re: The 2019 melting season
« on: August 22, 2019, 07:35:28 PM »
HYCOM Ice Thickness August 22 - August 29



I feel like HYCOM must have changed their scale or something because that literally looks like the end of ASI as we know it.
Scale or not, that relatively large patch of while right next to the pole must be something quite interesting. I wonder how that particular place will look like in a week from a satellite, there.

P.S. Oh, and don't underestimate ~0.5m of ice late-season. It'll hold pretty well, especially in CAB, provided weather is not destructive. Insolation rapidly declining is a big help.

83
Arctic sea ice / Re: The 2019 melting season
« on: August 22, 2019, 03:52:09 PM »
PETM - What do left and right sides represent?  Thanks
Left is averaged over few days, right is just raw daily data, iirc. Because we know certain processes, like clouds for example, influence daily maps quite much - so running averages are indeed quite helpful to see exactly alongside with daily maps.

PETM, perhaps it'd be best if you'd add exact description to each half in some automated way for future ones? Either into gifs themselves if your software can automatically do it for you once you set it up, or maybe just creating for yourself simple forum-post "form" for posting those animations, which would include such description - so you wouldn't need to type it manually every time.

And PETM, i take this chance to thank you very much for those new-style animations. They are indeed quite very handy. Kudos for your ongoing effort to make them, sir!

84
Arctic sea ice / Re: The 2019 melting season
« on: August 08, 2019, 10:13:06 PM »
Finland has been experiencing record cold the last day or two. I caught this tweet with an interesting chart that shows where the cold air is coming from. If this cold air is moving from the Arctic down over Finland, doesn't that mean warm air could be flowing in from elsewhere to replace it?
Not just Finland. Large parts of Russia are breaking minimum temperature records last week or so. For example, the capital - Moscow - had 4th August top temperature of 13.5C, lowest recorded during past 70 years. Saw reports of massive cold in Norwegia recently, too. Those are large parts - Scandinavia, Russia. And sure, whenever large mass of air leaves Arctic - similarly large amount must enter Arctic elsewhere. Can't be vacuum left behind, eh.

85
Arctic sea ice / Re: The 2019 melting season
« on: August 08, 2019, 02:59:39 PM »
A short 20-second video of a waterfall of melt water near the northern tip of Greenland - in this twitter post. Text in the video says "July 2019". I wonder what is happening in those parts now after days of open sky and high air temperatures...

86
Arctic sea ice / Re: The 2019 melting season
« on: August 05, 2019, 04:39:26 PM »
Weather on top of a continously loaded dice.
Loaded it already is, sure, but not yet as much as it can be i think. Far from. Those "lens" of warm water mentioned upthread, for example - clearly they are growing lately from season to season. So for this season? I'd say quite dramatic weather would be needed for anything close to "complete melt". Like, mega-GAC or such. The dice are not loaded enough to be otherwise - yet.

Any PIOMAS update?

87
Arctic sea ice / Re: The 2019 melting season
« on: August 05, 2019, 04:20:54 PM »
...
Yes, SST anomalies have gone crazy recently, on both the atlantic and the pacific side. Animation below for the past 6 weeks.

My naive reaction is that those anomalies around the CAA suggest that a complete melt out is possible there.

The thickness in most of the CAA is already very low according to PIOMAS, so I agree.
"Possible" is key word here - as noted before, now it's massively weather-dependent. Strong winds both towards and from remaing ice, water currents transporting some of those SSTs to ice, extra rain coming to ice (some of which added by those SSTs via direct evaporation and indirectly via a bit elevated background temperatures in the athmosphere), fog, larger temperature gradients of athmospheric systems somewhat affected by those SSTs among other things - i.e. weather.

88
Arctic sea ice / Re: The 2019 melting season
« on: August 02, 2019, 04:17:35 PM »
...
2019 definitely appears to be one of the worst years on this date. How bad will this melt season end up compared to previous worst years? Too early to tell?
Yes, too early. I see that unusually large amount of ice is now in the state which allows quick and massive melt under GAC-like conditions, by either low thickness, high fragmentation or both. In the same time i see large amounts of ice which are just barely enough thickness to survive if it'll be not too much wind and not too much insolation. I.e., the season arrived to the point where weather decides unusually much. And since "usual" is already pretty much - yep, too early to tell.

89
Arctic sea ice / Re: The 2019 melting season
« on: July 31, 2019, 09:33:31 PM »
Nope, not biting with that one on this thread :)
Oh well, back to concrete data then. About ESS, i'm sure someone better than me can give a summary of cloud cover over the region though the season, right?

As for me, i'll just humbly note that Greenland's summit station (~3200m elevation) observes (slightly) above-zero temperatures for the 2nd day in a row during past-noon hours, as seen on their website. Some 200+ hours forecast still lists 2030+ high over Greenland. I wonder how exactly many days it'd take meltwater pulse to reach sea ice after this. Probably noone knows though.

90
Arctic sea ice / Re: The 2019 melting season
« on: July 31, 2019, 09:03:44 PM »
...
Question. Is the late melting in the ESS, despite the southerly location, due to lower salinity, stronger ice, permafrost ~30m below, pacific and atlantic ocean currents causing compaction or other (your suggestion)?
Mainly other. As you note, it's southerly location, pretty much the last such southerly location to melt this season. I've seen signs through the season indicating ESS would give up much sooner than it actually did; further, quite a few others did the same - and posted as such upthread. And with pieces like this one, published all the way back in 2011... I tend not to believe in such coincedences. They clear the sky for military parades and they form clouds and cause artificial rain for agricultural purposes; heck, we now have large countries blaming each other of "stealing rain", even, you know? So i suggest, via Occam's Razor - the call was heard. Let's just keep it at that.

You asked for "suggestion", mind you - and so i gave one. If you'd ask for say "provable data" or "published source", etc, - then, of course, you would not hear it (even if i could actually prove it, because it's one dangerous thing to prove such a suggestion in public).

Cheers.

91
Arctic sea ice / Re: The 2019 melting season
« on: July 31, 2019, 01:54:19 PM »
...
Keep on posting stuff like this, Jontenoy. Ignore the ignorance of others.
I support; thank you for posting about 'em blueberries, Jontenoy. We need every bit of anyhow related observation we can get.

P.S. It ain't just blueberries and anecdotal, as it turns out: in Lithuania (not too far), "winter barley matured really early. And it surprised that winter barley matured in the middle of July. I don't remember such a thing over my 20 years of farming".

92
Arctic sea ice / Re: The 2019 melting season
« on: July 30, 2019, 06:36:27 PM »
As of today, the Greenland's highest point surface temperature became above 0C (just 1 pixel above 0C line) and stays there for a few hours already (this is measurement, not modelling). Means even the summit, which is ~3200m above sea level, will see at least some melt despite all the elevation. The amount of heat at lower elevations (and thus melt, and thus meltwater going to do bottom melt to sea ice later on in the season) - will thus be huge.

93
Arctic sea ice / Re: The 2019 melting season
« on: July 30, 2019, 06:10:10 PM »
...
Anyone care comment on the North African heat bomb that roasted Europe and has just lit up Greenland and Ellesmere heading for the Lincoln Sea?
Well, i commented about it 7 pages ago - i mean this one. And if you mean to comment current situation - well, not much to say. It's insane and it's happening:



As for what exactly consequences for sea ice and melt season will be - remains to be seen...


94
Arctic sea ice / Re: The 2019 melting season
« on: July 27, 2019, 10:57:46 PM »
I agree, for now 2019 seems to be more compacted and hopefully resilient near the pole, same as 2012 and unlike 2016.
Why "hopefully resilient" if we say that near the pole will re-freeze early September, though? If you mean wishing well for arctic sea ice in general, through the seasons, - then it's not much difference IMO. Multi-year ice is pretty much history now, anyway; and winter will refreeze "near the pole" quite very well anyhow - next freezing season, i mean. Far not enough ocean heat content to prevent it - for now.

Meanwhile, as if recent insane temperatures in northern parts of Canada and predicted very strong high over Greenland would not be enough, - we now have masses of hot air from Sahara and Spain heading towards Greenland, they say. It's that same heatwave which killed people in Europe just few days ago which now goes to "visit". Yet even worse its effects will be if that high pressure would then "anchor" itself in the region through self-enhancing clear sky extra heating.

We know it can happen, because it already happened in very similar circumstances: in 2010 over central Russia, about same time of the year (July / August), more than a month of unprecedented heat and clear skies - and in that case air masses came from dry desert lands much closer to the equator, too. Almost choking Moscow and whole regions in smoke from all the fires around, destroying ~90000 km2 of farmlands, etc - saying this just to illustrate how big, bad and long those "stuck" highs can be. Game-changer kind.

95
Arctic sea ice / Re: The 2019 melting season
« on: July 27, 2019, 08:50:20 PM »
... I think (under current decade realities) the more high-Arctic melt there is, the sooner will be the minimum.
snippage ... The general trend also disagrees with you: see figure 3 on this page.
I actually agree with Tor and I don't think NASA diagrees. The Sept. minimum is reached at the onset of refreeze. After that, the fall freezing can be very delayed. Both of these effects happened in 2016, the year that made the biggest attack on the very high arctic near the pole, and was therefore hit with an early refreeze onset on Sept. 8th or 9th. ... snippage
Most interesting! Ok, Oren, you got a point about NASA line, so let's just forget about it. But what about general trend? As for 2016 - wasn't 2016 very unusual weather much of the season? And anyhow, it's a cherry. How about i pick another cherry and remind you that 2018 season ended as late as September 23rd or so? ;)

And then there is one other simple point about this: season's end is by extent, and this season shows no sign of huge extra losses of extent exactly in CAB at the minimum, no? It ain't looking to go to something like 2016 minimum, when large amounts of ice survived outside CAB in pacific and siberian sectors, iirc. So you see, early re-freeze in the CAB would not add that much extent, this year.

96
Arctic sea ice / Re: The 2019 melting season
« on: July 27, 2019, 08:13:03 PM »
Shared Humanity, while i disagree, my respect to you is greater than my disagreement with this particular opinion of yours. I did as promised and removed those couple posts which you deemed not helpful. And again, thank you for caring about it, sir. :)

97
Arctic sea ice / Re: The 2019 melting season
« on: July 27, 2019, 07:59:40 PM »
... I think (under current decade realities) the more high-Arctic melt there is, the sooner will be the minimum.
NASA pretty much disagrees with you: "The increases in surface ocean temperatures, combined with a warming Arctic atmosphere due to climate change, explain the delayed freeze up in the fall". Source. The general trend also disagrees with you: see figure 3 on this page.

98
Arctic sea ice / Re: The 2019 melting season
« on: July 27, 2019, 01:54:56 PM »
Few pages ago, i wrote about my concern about gigatons of melt water going from northern side of Greenland into the ocean, adding to bottom melt of ice in the region. I'd like to have better estimate about how significant this effect is. I checked few places, and i found clear confirmation of the effect in the form of darker shades of green for 2m temperatures over both open water and still ice-covered areas of the ocean adjucent to northern side of Greenland in this forecast - click "right arrow" button there to animate.

A bit of those darker shades of green move somewhat towards the pole (and eastwards) and as far as more than half distance to the pole, at some point, as one can see.

Thing is, those are 2m temps - not SSTs. Means, while warm melt water affects it - many other things affect it also. Thus, i'd like to know SSTs of the open water areas north of Greenland. What would then be the most respected resource which would demonstrate SSTs for the area, either observed or forecasted or both, real-time?

P.S. Checking under-ice topography of Greenland, it's obvious quite many within-ice configurations of melt water bodies and channels will result in much, if not most, of melt water discharge from central greenland to end up running to the ocean through north and north-east edges of Greenland. So, given forecasted and massive snow cover melt i mentioned earlier in the topic and that topography, dozens-gigatons melt water pulse soon after the peak of the forecasted high over Greenland seems quite unavoidable, to me. Anywhere i am hopefully would be mistaken about this all - please tell...

99
Arctic sea ice / Re: The 2019 melting season
« on: July 27, 2019, 12:40:25 PM »
Take your pick. dmi, hycom jul3-25 and piomas jul3-15

Is there any chance to measure sea ice thickness (at least at some points) by ships/expeditions in the CAB and to compare the measured data with the modeled data and (maybe) adjust the models to the reality?
Measure - yes. Compare - no. See, the measurements are being done all the time. Problem is, for some reasons publishing those measurements - is not possible for any modern times. Historical measurements - pre-2000 - are easily available, as mentioned, for example, here.

edit:
I have just returned from Croatia. Thanks to everyone for the condolences. In coming days, I'll try and get things in order here on the Forum.
It is great to see you back and to see your spirit strong, man! But you sound still grim. I understand. Been there, 28 years ago... Please, do always remember: he's not dead yet - as long as you are alive and your memories of him are alive, he is in a certain and very real way still alive. Nothing mystical, pure neuro-biology here. I'm sure you can see how it works if you'd think about it. Salute!

100
Arctic sea ice / Re: The 2019 melting season
« on: July 26, 2019, 11:47:44 PM »
If you compare 2012 and 2019 and consider  only the pink/purple area...

Be careful comparing singles of these images. They fluctuate a lot daily, presumably due to cloud artifacts. Which is why I have been posting median images (as gifs). E.g., Attached is the median of July 22-24, 2019 (3 days). Paints a slightly different picture I'd say.

petm,

you could be right about this but i am not convinced yet :)

can you do the same median for 2012 so that we can compare the two?

thanks
I am (convinced), too. They often fluctuate wildly, and from what i saw of them, it seems to me that 3-day averages is even not quite enough. 7-day running means would probably show much more consistent picture.

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