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Messages - F.Tnioli

Pages: [1] 2
1
Arctic sea ice / Re: The 2020 melting season
« on: June 18, 2020, 06:22:13 PM »
A June cyclone is very different from an August cyclone. August has weak ice, warm water and not much sun, ideal conditions for a cyclone to cause immense damage without paying in lost insolation. In June conditions are very different, thus IMHO GAC designation should be reserved for August.
Different - yes. Very. But anyhow so much weaker in terms of ice-killing effects as to deny it "GAC" classification? Hell no.

Consider:

- any cyclone that strong wipes out remaining high-albedo snow cover really well, no matter how thick's the ice, and there is still month+ of very high insolation to follow. Direct result of such a GAC during said month+ following? Plenty extra ice melt, which effect is nearly absent for an August GAC;

- any and all "lost" insolation is in fact not lost at all, rather, it is absorbed by GAC itself. Fortunately, only a fraction of that energy will end up reaching the ice; unfortunately, GAC cloud masses tend to have much lower albedo than "best case" June's fresh-snow-covered sea ice; and unfortunately, much more energy from insolation GAC itself absorbs in June - could intensify the GAC itself, i.e. stronger winds, higher temps, etc (in compare to same GAC in august). End result? Comparable to direct insolation energy transfer to the ice, exactly because it's June (max insolation) and not August (low insolation, plenty energy lost in stratosphere due to low average sun angle over horizon);

- whateever mechanical / wave-action damage is done in June will have consequences for the rest of the season. While in August, whatever parts of "weak ice" end up grinded by the storm to open water state - those parts will not "suffer" any more in terms of further ice lost, since they are already 100% open water.

I.e., June GAC is very possible given specific circumstances. I'd say most important is mechanical integrity of the ice, which in this melting season is cleraly much lower than even "recent average" (like 2010's average). Pretty sure we can be very (unpleasantly) surprised about what this emerging could-be-a-GAC can do.

Oh and about naming. I wouldn't name it "the GAC 2020", because i deem it quite likely we'll see more than one GAC this season. Possibly ~5 even. Thus, how about "GAC '20/1" or somesuch.
Thank you for this explanation FT. That is how I understood it as well. A storm at this time of year will have its consequences felt throughout the remainder of the season. Thus adding energy to the system.

A storm at the end of the season will just destroy the ice and stir up the ocean, bringing warmer water to the surface that will then lose its heat to the atmosphere. That's why I still find it difficult to accept Binnto's explanation that storms always add energy to the system. I understand what you mean Binntho, hot moist air blowing over the ice at speed will melt it, but maybe I'm just stubborn, I still think that storms suck in hot air at the bottom that gets cooled at the top, effectively cooling the ocean and the air at the surface. If this happens at the end of the season, then storms take out energy from the system. I think this is proven by the recovery years after the 2012 GAC, no?

How about JAC? The June Arctic Cyclone... And because my name is Danny, and I brought this up first, we could just call it the JAC Daniels storm?  ;D

2
Arctic sea ice / Re: The 2020 melting season
« on: May 26, 2020, 03:47:15 PM »

3
Arctic sea ice / Re: The 2020 melting season
« on: May 25, 2020, 12:38:41 AM »
It's so insanely warm (relatively speaking) in Utqiagvik today! Not the mention the amount of melt ponds on the landfast ice appeared almost instantly. So too did the melting of the lake. Wild!


Timely indeed.

Hey Friv, you hear this? Melt ponds appearing almost instantly. I told you it will happen in 2..3 weeks - exactly 3 weeks ago (this post), when you said it'll be in a month. See, things go wild this time, you see what happens with albedo and i bet you know how it goes.

Think Slater's right?

I've followed all of this for a while now and don't ever remember seeing melt ponds of any significance occurring in the month of May. Moreover, I'm fairly convinced these conditions are mirrored or worse in both the East Siberian and Kara Seas. Wherever there is any open water in the arctic right now, it appears as +1-5c anomalously warm.

I'll gladly eat crow, but I think this will be the earliest breakup up landfast ice around Barrow and even the Beaufort's small buffer of ice facilitated by a cold winter in that region will not overcome May's weather. I think the entire pack has been affected, especially given how mobile it seems this year as a result of the widening and expansion of cracks along the entire northern coast of Greenland, which is historically older, thicker ice

4
Arctic sea ice / Re: The 2020 melting season
« on: May 24, 2020, 10:50:33 PM »
It's so insanely warm (relatively speaking) in Utqiagvik today! Not the mention the amount of melt ponds on the landfast ice appeared almost instantly. So too did the melting of the lake. Wild!


5
Arctic sea ice / Re: The 2020 melting season
« on: May 24, 2020, 09:54:24 PM »
The ice is very blue in the Hudson bay despite the land snow refuses to melt in that region during the entire spring.

6
Arctic sea ice / Re: The 2020 melting season
« on: May 24, 2020, 09:14:14 PM »
Slater's model has picked up the current preconditioning  and thinks it is favourable for strong melting way into July.
It predicts 7.34 m km² for July 13th, currently nosediving ...

   Wow, if that forecast verifies, then 2020 would be 600K and 8% below the previous records for July 13 Extent in 2019, 2016, 2012. 

    It is useful to have Phoenix provide a skeptical check on habitual ASIF catastrophism (as in "this year is the big one!"), but it is also true that 2020 has come out of the gate strong, and that the current Extent and Volume numbers do not yet reflect the preconditioning that has occurred.  In addition, the current GFS forecast shows surface temperature for most of the Arctic Ocean above 0C from May 29 - June 3, combined with substantial areas of clear sky and what seems to be high amounts of precipitable water along the Atlantic front and north of Greenland (but I lack the historical perspective to interpret the precipitable water forecast).   

    I worship at the church of the long term linear trend, which has the 2012 volume record remaining intact for 2020 but then a ca. 50% chance of falling in 2021, and increasing each year thereafter.  For Extent, the trend estimate shows the 2012 record being safe for 5-10 years.  While it is far too early to say anything definitive about 2020, considering the recent conditioning, the current GFS forecast, that scary albedo graph posted by Sublime_Rime, and the Slater model forecast (which has been pretty accurate in recent years), 2020 seems to have a greater than 50% chance of going below the 2012 volume record.  The Extent record from 2012 was due to a freak event (the GAC) that is unlikely to be repeated in 2020, so is less likely to be surpassed.  But that is less important anyway, as I also worship at the church of Volume vs Extent with the Rev. Juan C. Garcia.

7
Arctic sea ice / Re: The 2020 melting season
« on: May 24, 2020, 07:01:49 PM »
<snip>
I'm not sure how often this occurs, but in this case we're likely to have 2020 take the area / extent lead in early June on the basis of early advantage in peripheral areas that is destined to be short lived.

It could be good for site traffic to get a new leader for a while, even if it doesn't last.  ;D

Or maybe it does! tee-hee  :-X :) ;) ;D

Slater's model has picked up the current preconditioning  and thinks it is favourable for strong melting way into July.

It predicts 7.34 m km² for July 13th, currently nosediving ...


8
Arctic sea ice / Re: The 2020 melting season
« on: May 17, 2020, 08:19:02 AM »
I mentioned earlier that I belive that most of the cloud cover that ends up in the Arctic actually originates in the mid-latitudes, coinciding with the areas seeing the biggest fall in aerosols.

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

Hardly any rain here (20 mm in 2 months, while average is 120 mm for 2 months) as well and lots of sunshine in March-April-May (basically since the lockdowns started). No proof of the lockdown-aerosol reduction effects, but I think there could be something to it. I have never seen so far, so clearly from our montaintop, I could see other mountains 2-300 kms away. Air was very clear and cloudless during the lockdowns. This is of course only anecdotal evidence but still...

9
Arctic sea ice / Re: The 2020 melting season
« on: May 17, 2020, 06:54:37 AM »
The last 2 Monti’s felt very sunny in the Netherlands and it also entered the recordbooks as most sunny april since we started measuring it.

And at the ‘higher’ areas drought is getting a real probleem; farmers who aren’t allowed to use water for their crops

And last weeks of march and first weeks of march are the same



Just checked some statistics, we had 560 sunhours since march 15th, former record was 503, which was in 2011; and only  23mm of rain

10
Arctic sea ice / Re: The 2020 melting season
« on: May 08, 2020, 11:41:33 AM »
For the benefit of any lurkers....

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

11
Arctic sea ice / Re: The 2020 melting season
« on: May 06, 2020, 01:31:04 AM »
It looks like last week has been good for the ice. Volume has increased again.

12
Arctic sea ice / Re: The 2020 melting season
« on: May 04, 2020, 10:05:12 AM »
And there was even more open water on thr Pacific side in 2016. But it's not the only thing that matters. The melting season in the High Arctic hasn't really begun yet, we will wait and see.

13
Arctic sea ice / Re: The 2020 melting season
« on: May 02, 2020, 07:28:44 PM »
Hi F. Tnioli .. I have been raising a similar hypothesis here for some years .. low angle sun melting near vertical ice faces .. my thoughts were mostly relating to the exposed fracture surfaces as they seemed to increase in number over the years , Last year I was remarking on the obvious 360' melt and run-off on the steep slopes around an mini island ice sheet N of russia while the horizontal surface was unaffected . b.c.

14
Arctic sea ice / Re: The 2020 melting season
« on: May 02, 2020, 12:44:08 PM »
Can you see the bear? Anyhow, from the accompanying note posted at nasa.gov, we can read that the bear is, quote, "standing behind Met City near a small lead, likely waiting for a seal". Earlier in the note, we also read that bear, quote, "... sat near a small crack in the ice for almost two hours, likely waiting for a seal to surface".  Seals, i understand, would need open water to come onto the ice, where polar bears could hunt them.

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

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

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

15
Arctic sea ice / Re: The 2020 melting season
« on: May 01, 2020, 09:25:22 PM »
... Animate it ...

Here you go! :)

16
Arctic sea ice / Re: The 2020 melting season
« on: April 30, 2020, 09:39:28 PM »
Hmmm... 🤔


17
Arctic sea ice / Re: The 2020 melting season
« on: April 24, 2020, 03:09:40 PM »
It looks like the DMI volume may have passed the season maximum.


18
Arctic sea ice / Re: The 2019/2020 freezing season
« on: February 26, 2020, 03:25:18 PM »
hi.
I live on 60N in Scandinavia and this has been the 'new normal'  winter for a decade at least. Our winters are getting much shorter as a result.

But there is no punch at all in the sun at these latitudes in Feb., and March. It's not gonna bring in "massive extra heat" as you write. In April insolation is strong, but by then snow is mostly gone anyway.

A few remarks:

- you may not feel the punch in cold air-masses and the frequent inversions where the air at ground level and close to it is colder than at some higher altitudes.

- nevertheless the energy that can be measured, even at low sun-angles IS SIGNIFICANT.
. In fact, compared to zero it's even huge while not TOP-Level of course.

- Said energy, meeting darker surfaces, makes a "HUGE" difference. Not only in absorbing
. energy but also by quicker melting of the remaining and/or existing snow cover.

- 60N is slightly north of  Oslo and goes through St. Petersburg to name just 2 of the largeer and
. better known places. That's "NOT" very far north, it's around the northernmost tip of the UK.

Whatever the details, the impact on darker surfaces, compared to white surfaces, is significant at "ANY" sun angle. Even though our thickly dressed protected skin does not feel that way, last but no least due to wind and humidity as 2 of several key factors. More humid air in winter often sticks to the ground with an impact as described above.

There is more to it but then I only wanted to +1 F.T.,
I found his description, in all briefness, kind of spot on.

Thing is that if we write long/much, it's frowned upon. If we write short, those with a tendency to find a hair in every soup would easily find their "angle of attack" while the original meaning
was quite accurate and mostly well meant.


19
Arctic sea ice / Re: The 2019 melting season
« on: September 20, 2019, 09:28:03 PM »
Quote
You've missed the main points. What sark was noting is that the larger problem (destabilization of the atmosphere) is impacting this melt season.

Second, that this will get more extensive in succeeding seasons and we need to expect and look for that.
The first point is relevant here, but the second belongs in its own thread and should only be referenced, not discussed ad nauseum in this thread. Like we do not discuss coal growth in China here, though all know it is very relevant. So please, enough with the hijacking (and with quoting terribly long nested posts in full).

20
Arctic sea ice / Re: The 2019 melting season
« on: September 12, 2019, 01:54:55 PM »
Since cross posting seems to be the order of the day, here are some images of the sea ice east of Svalbard on September 3rd, courtesy of the Norwegian Coastguard via the "Great White Arctic Sea Ice Con" thread:






21
Arctic sea ice / Re: The 2019 melting season
« on: August 22, 2019, 05:32:27 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.

22
Arctic sea ice / Re: The 2019 melting season
« on: August 22, 2019, 04:58:33 PM »
PETM - What do left and right sides represent?  Thanks

Right side are the original (cropped)  Bremen AMSR2 concentration maps, NIC color style (key attached here).

Left side are per-pixel minimums for 5 trailing days.

Minimums are bad at detecting rapid ice motion from low to high concentration, melt pond refreeze or new ice formation unless it persists 5+ days, etc. But they are good for one key thing: seeing through the many cloud artifacts in the originals.

The idea is to use the minimums together with the original to help interpret what's happening in actively melting areas. They also seem to generally do a good job at mapping the true, persistent high- and low-concentration features.


PETM, perhaps it'd be best if you'd add exact description to each half in some automated way for future ones?

Good idea. I've gotten lazy. And you're most welcome. :)



Re: The O/T.

For me, I used to cheer for a big melt, thinking it might catalyze collective action, but I no longer believe it will matter. (There's zero chance our collective economy will change fast or far enough to avert catastrophe.) So now, I just watch for the enjoyment of witnessing and trying to understand a little of how such a mind-bogglinginly massive and complex system will lurch into a dramatically new state.

23
Arctic sea ice / Re: The 2019 melting season
« on: July 31, 2019, 05:49:27 PM »
Always good to have persons who don't normally contribute to post comments but this comment would be better posted here...

https://forum.arctic-sea-ice.net/index.php/topic,1786.0.html

Best to leave this thread focus only on the melt season.

+1

Also, for discussions of questionable importance to the current melt season:
https://forum.arctic-sea-ice.net/index.php/topic,2274.0.html

And for meta discussions about what should or should not be posted and where:
https://forum.arctic-sea-ice.net/index.php/topic,1562.0.html

Among other threads...

24
Arctic sea ice / Re: The 2019 melting season
« on: July 27, 2019, 04:20:47 AM »

And I am not sure I agree that the CAB averages >2M thickness - not sure where that number comes from.

I wondered the same thing.  The area numbers are very hard to interpret this time of the year.  They can change for many reasons, and unless he knows a Russian or American submarine commander, there is no way to know how thick the ice in the CAB is right now.
PIOMAS volume divided by NSIDC sea ice area seems the only logical way to do it without physical observations, and here it is.....

Note that it seems to have lost 1 metre of thickness since the 2000's, but at mid-July was at 2.4 metres.   Usually what happens now is that scorn is placed upon the data for being awkward.

I decided last night I was done posting in the melting thread because Rich has accomplished his purpose of turning scientific discussions into his personal activism and it pisses me off! 

But this point is important and needs to be addressed.  PIOMAS is a model.  It is helpful, but it is not real data. I work in the environmental field and deal with models everyday. 

I doubt many others here can say that.  We know PIOMAS makes many mistakes, but it is the best we have so we use it.  That does not mean we can blindly say when it predicts a certain volume of ice in a place we can clearly see on worldview is wrong we should accept its output.

Area is also notoriously bad this time of year.  That is why JAXA and NSIDC use extent to measure the summer minimum. 

Dividing a fictitious number by a known bad number does not give any real data.

The best information we have is what we see on worldview.  The next best info is the extent data that JAXA and NSIDC provide. 

Models are useful, but they are not real data. 

25
Arctic sea ice / Re: The 2019 melting season
« on: July 25, 2019, 04:42:08 PM »
HYCOM - Arctic ice thickness (CICE) model - July 25 - August 1

RIP Ice :'(




26
Arctic sea ice / Re: The 2019 melting season
« on: July 24, 2019, 06:13:36 PM »
I saw couple signs that say that you're absolutely correct about the CAA part, lately. And very true about extent and area, too. Apart from (often difficult, uncertain, or not available) measurements of current ice volume / thickness, i'd say small dips in concentration % could sometimes be one useful hint about such processes. I wonder if you use that as one of quick things to check, yourself.

Well, hints like that help, certainly. One of the challenges, of course, is determining how to section off areas for analysis. That's why I tend to focus on just the Sverdrup Islands, rather than wider areas like the Queen Elizabeth Islands or the whole of the CAA.

Even a small change in one of the satellite-discernible metrics (area, concentration, extent) for the Sverdrups alone is likely to be significant. But changes of similar magnitude for the whole of the CAA are potentially just noise. For example, the CAA's conventional boundaries include the North Water Polynya, at least in part. The CAA also includes smaller areas of continuously (or nearly so) open water, including at the west end of James Sound (at North Kent Island) and in the general vicinity of Bailie-Hamilton Island. Even absent significant regional melt or fragmentation, the exact boundaries of these open water phenomena can easily swamp the signal of more concerning events when considering the region broadly.

27
Arctic sea ice / Re: The 2019 melting season
« on: July 23, 2019, 09:11:25 PM »
Insolation at 90 degrees is greater than at the Equator until the first week in August.

Ought to settle this question.
Except that the albedo of the underlying surface is in large part a function of the angle of incidence of the solar radiation. This is true not just for water but also for sea ice.


Source: Hudson, 2011 https://doi.org/10.1029/2011JD015804

At 90°N latitude at this time of year the solar zenith angle is about 70° so that all the time is spent in the high-albedo part of the curve. South of 30°N, once the sun rises, almost all daylight hours have a solar zenith angle less than 70° and for much of the day less it's than 40°; at tropical latitudes it can obviously reach 0° at high noon. The end result is a great deal of time is spent in the low-albedo part of the curve.

I have no idea how to quantify this difference. My point is that it's not as simple as calculating the theoretical 24-hour solar insolation based on latitude alone and calling it a day.

28
Arctic sea ice / Re: The 2019 melting season
« on: June 20, 2019, 06:38:57 PM »
Amount of ice is defined not just by extent and area, but by the combination of area and thickness (and extent is really not needed). Thickness is missing here.

How on Earth anybody would properly conclude "more ice in general in that location" based on those couple graphs only - i honestly don't know. "Suspect"? Sure, doable. "Likely"? Perhaps. But for sure? Hell no.
Just for you..
- NSIDC Area,
- PIOMAS Volume,
- Thickness - PIOMAS Volume divided by NSIDC area

I think they all say a bit of a hiccup in Beaufort's record losses to date.

NOTE: Volume and thickness to 15th June, area to 19th June

29
Arctic sea ice / Re: The 2019 melting season
« on: June 20, 2019, 06:30:43 PM »
The weather models are basically shocking.

Day 1 through 4 see a huge Ridge over the Pacific side very bad for the ice.

But around day 4 this Ridge becomes epic level expansive.

Like what the fuck.

That is all

Whoa. When Friv is stunned into writing short, simple sentences with no wildly descriptive adjectives, that scares the shit out of me. I may not know how to read the weather, but I know how to read the Friv.

30
Arctic sea ice / Re: The 2019 melting season
« on: May 29, 2019, 04:08:08 AM »
everything looks potentially catastrophic except , as Gerontocrat points out , the figures .
IMHO, top line numbers never mean much, particularly extent (unless you fancy a boat ride). Look at the Beaufort for example this year vs. 2016. Extent just increased, but I'd say the prognosis is terrible: huge areas of open water between very few large floes. Frankly it's not even clear to me what matters; we may not know it until we see it. One possibility: is halocine degeneration looming (and if so what conditions might accelerate it) (https://physicsworld.com/a/strength-of-arctic-halocline-indicates-climate-change/).

31
Arctic sea ice / Re: The 2019 melting season
« on: May 28, 2019, 04:13:34 PM »
An animated comparison with 2016 from Wipneus' "Home Brew AMSR2" thread:

Which is currently removed has been reuploaded whilst I try and work out why it autoplays in here but not over there.

32
Arctic sea ice / Re: The 2018 melting season
« on: August 07, 2018, 07:25:55 PM »
general suggestion:

i suggest that everyone who is posting image with a color scale should post the indicator table with it so that everyone can see what each color or grayscale means.

if the colors would be unified that wouldn't be necessary but each provider is using different color sets with different color zones so to say, hence without looking up the original with the scale
those images are raising at times more questions than they answer.

an alternative would be to add the link to the original if the scale is too far off the image that would make the posted image too large ( or smaller for the eye)

33
Arctic sea ice / Re: The 2018 melting season
« on: August 07, 2018, 03:32:38 AM »
What I am interested in is whether the end of the melt season be later than normal.
Following up on a post in the data thread:
If the ice distribution at minimum is similar to the outline posted above, of a bunch of ice compacted around the center of the CAB and along the CAA, in the style of 2012, we may very well have a later end to the season. In contrast, 2016 had an early minimum on Sep 8th due to lots of low concentration ice deep inside the pack adjacent to the pole, which made it vulnerable to an early cold spell both due to the high latitude and the prevalence of cold fresh surface water. 2012 had a later minimum on Sep 16th

34
Arctic sea ice / Re: The 2018 melting season
« on: August 02, 2018, 03:52:35 AM »


Does the setup of the past months resemble a two-cell system instead of the classic three-cell system setup in the NH? If it stays like that also for the winter, what are the consequences?

The way the lows were repeatedly ratcheted into the Arctic seas, attached to troughs drawing hot air from the mid latitudes suggests the Arctic cannot keep itself separated from the lower latitudes. As a relative newcomer here I don't have a sense of how new or unusual that is, when time permits I'll try to find reanalysis of previous summers for comparison(Climate Reanalyser publishes the whole years worth at the start of the new year).

JAXA is offline for a few days. Arctic ROOS' ssmi is now showing extent at record low since a couple of days ago, just at the time the recent years begin to diverge(area starts doing the same about a week or 10 days earlier - on ROOS, area is still relatively high, a week ago it was highest for the decade!). 2012 started its big plunge a few days further into August. Interesting times.

Arctic ROOS is at https://arctic-roos.org/observations/ice-area-and-extent-in-arctic

35
Arctic sea ice / Re: The 2018 melting season
« on: June 13, 2018, 02:27:37 PM »
As far as i see it, the models are not telling that no ice melted. The models are telling that plenty of ice melted. Only that area on the siberian side lost maybe 500 km3 in the last 10 days. If the graphs are right.

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