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be cause

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Re: The 2020 melting season
« Reply #2350 on: July 07, 2020, 06:14:39 PM »
The 5 day average NSIDC loss in the CAB on July 4 was 83.8k km2 or a total of 418k for the 5 days.

The current 5 day average through July 6th is 15.7k km2 or 88.5k km2 for the 5 days.

The difference in CAB area decline for the two days that left the 5 day average (June 30 and July 1) and the last two days that entered the 5 day average is 330k km2.

There are many potential explanations and I'm not going to try. Just an interesting bit of data to mull over.

melt ponds draining .. next step on the way to iceobliteration .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 + 2 = 2021 
 (phew)

Pagophilus

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Re: The 2020 melting season
« Reply #2351 on: July 07, 2020, 06:16:20 PM »
If you want to see what happens next if we have another week or two of anticyclone followed by whatever comes next take a look at Kara/ CAB . Browned ice is simply vanishing in situ. The streak from 79N 90E to 82N 90E ..@ 50,000 sqkm of 3 days ago has been collapsing .. especially where it has been pushed toward the island
  https://worldview.earthdata.nasa.gov/?v=815180.4200908248,944464.758704975,1164876.4200908248,1112656.758704975&p=arctic&t=2020-07-05-T15%3A10%3A34Z&l=Graticule(hidden),Coastlines(hidden),VIIRS_SNPP_Brightness_Temp_BandI5_Night(hidden,palette=green_1,min=220.7,max=240.2,squash=true),Reference_Labels(hidden),Reference_Features(hidden),VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor


 just play the next 2 days .. b.c.

I did.  You are right.  That's not working out too well for the ice the Kara...  :o
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gerontocrat

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Re: The 2020 melting season
« Reply #2352 on: July 07, 2020, 06:20:39 PM »
Very interesting visualisation!

Arctic Sea Ice Volume and Extent June 2020

Video at link >> https://www.reddit.com/r/dataisbeautiful/comments/hml6v8/arctic_sea_ice_volume_and_extent_june_2020_oc/

via /u/kevpluck

That is indeed interesting.  One thing I noticed is that a line where y=x, which (loosely) represents the average ice depth being 1 meter, appears to now be reached during the part of the year when extent is around 8*10^6 and volume around 8*10^3, but perhaps not reached at the annual minimums (yet).
To use extent in the calculation of thickness is bad news...it underestimates average thickness especially at the minimum (when sea ice concentration is lowest) by up to 40%.

Thickness = volume / AREA;  not volume / EXTENT.

Attached is volume, area & average thickness at the minimum - September MONTHLY averages.
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Freegrass

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Re: The 2020 melting season
« Reply #2353 on: July 07, 2020, 06:23:18 PM »
Browned ice is simply vanishing in situ.
What makes the ice brown? You don't see that on thick ice, so is the ice so thin that the dirt (algae?) on the underside gets exposed? Or are those the remnants from black carbon that fell on the ice?
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Pagophilus

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Re: The 2020 melting season
« Reply #2354 on: July 07, 2020, 06:42:29 PM »
Browned ice is simply vanishing in situ.
What makes the ice brown? You don't see that on thick ice, so is the ice so thin that the dirt (algae?) on the underside gets exposed? Or are those the remnants from black carbon that fell on the ice?

I remember this being discussed last year, and that algae is indeed a major culprit here. I had kind of forgotten about all that, so thank you.   

The following paper may help, and the following quote from it.  Sorry, don't have a proper citation

https://arxiv.org/pdf/1702.03325.pdf   Light Absorption in Arctic Sea Ice – Chlorophyll and Black Carbon    O. Ogunro et al   
 
"In the boreal spring, light absorption by chlorophyll present in certain layers of Arctic sea ice
may thus be significant when compared to the contribution of anthropogenic BC. Some
biological habitats including the bottom and infiltration layers are quite absorptive, approaching
or surpassing the value for black carbon. During the contemporary period, it is suspected that
thinning sea ice will lift radiation restrictions and allow biological activity to increase.
Meanwhile black carbon point sources are being restricted under new environmental regulations
in most developed countries at the Northern Hemisphere [Bond et al., 2010]."

BTW: Anthropogenic carbon has gone down with the global slowdown, but deposited BC from Siberian fires may have gone up.
« Last Edit: July 07, 2020, 06:52:47 PM by Pagophilus »
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blumenkraft

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Re: The 2020 melting season
« Reply #2355 on: July 07, 2020, 06:55:03 PM »
just play the next 2 days .. b.c.

"Pay it, Sam. Play 'as time goes by."

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Re: The 2020 melting season
« Reply #2356 on: July 07, 2020, 06:59:54 PM »
The 5 day average NSIDC loss in the CAB on July 4 was 83.8k km2 or a total of 418k for the 5 days.

The current 5 day average through July 6th is 15.7k km2 or 88.5k km2 for the 5 days.

The difference in CAB area decline for the two days that left the 5 day average (June 30 and July 1) and the last two days that entered the 5 day average is 330k km2.

There are many potential explanations and I'm not going to try. Just an interesting bit of data to mull over.

melt ponds draining .. next step on the way to iceobliteration .. b.c.

It's interesting to consider how so many melt ponds come to drain at the same time in just a Arctic single region.

Is there a thread on the life cycle of melt ponds which explains the apparent group behavior? 


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Re: The 2020 melting season
« Reply #2357 on: July 07, 2020, 07:01:34 PM »

To use extent in the calculation of thickness is bad news...it underestimates average thickness especially at the minimum (when sea ice concentration is lowest) by up to 40%.

Thickness = volume / AREA;  not volume / EXTENT.

Thank you, that makes a lot of sense.  I'm instructed.
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oren

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Re: The 2020 melting season
« Reply #2358 on: July 07, 2020, 07:04:51 PM »
If anyone is wondering where their responses to Phoenix's surface temps issues disappeared, it's all been banished to the basic melting physics thread.

oren

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Re: The 2020 melting season
« Reply #2359 on: July 07, 2020, 07:12:38 PM »
So, as a non-expert, let me see if I have got this straight...

The current anticyclone over the pole looks set to compact the ice and warm the Arctic generally.
 
a. It will compact the ice pack by 'pulling' ice inwards (really the Coriolis Effect), probably producing much more open water in the Chukchi, ESS and Laptev, and maybe in the Beaufort too.  This is already happening.

b. The extra areas of exposed seawater will then soak up a whole lot of near-maximum 24/7 Arctic insolation, warming their surface waters.  The warm water will remain at the surface because of its low density.  (Upwelling may also occur in places, bringing warm, saline water to the surface in places.)  All this seems probable, especially with the forecast clear skies.

d. Compaction will probably make for dramatic extent losses, but not necessarily in and of itself be terrible for the ice in terms of ice volume, since overall melting will be reduced when all the ice is together.

The rest is more speculative.
Pagophilus, I'd rather this discussion take place in another thread. However a quick answer is needed to avoid misunderstandings by other readers.
The HP both compacts and warms the Arctic. Compaction is due to the anti-cyclone and Coriolis. Warming/enhanced melting is due to higher insolation (caused by less clouds) and warm air sinking (I hope I am getting this correctly).
Compaction per se does not bring more energy to the ice, as it just shifts ice area from one place to another. If anything, it may make the ice more protected as it is bunched together and in a higher latitude. Of course, a low that then disperses it could undo this process.

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Re: The 2020 melting season
« Reply #2360 on: July 07, 2020, 07:43:36 PM »

The surface temperature of melting ice is always going to be zero until the ice has melted and turned into water - that's thermodynamics -

Attached is the latest DMI 80N temperature chart. It shows the 2m temps coming down from an above normal peak. The forecast calls for a further decline in a few days. If it's not clear, I'm referring to temps at 2m, not at 0m.

http://ocean.dmi.dk/arctic/meant80n.uk.php

What exactly is the value of this insanity? Temperature at 0m is the around 0C (in the summer) because there is ice at 0m.

Temperature at 2m is close enough to the ice to be anchored around a very tight range around 0C during the summer months. You clearly know and understand this based on previous posts. Yea, there may be tiny fluctuations but there is absolutely zero analytical value in looking at a snapshot of 1 week and calling peaks and declines.

Stop attempting to derail constructive conversation because you are bored at home during Covid or whatever your affliction is.

Yes, I understand that the 2m temperature above the CAB ice is bounded to a relatively narrow range. I think the changes within that narrow range are meaningful. Others don't. We can respectfully disagree about that.

The DMI 80N temperatures have been shared here for a long time. They have an imperfection in methodology regarding weighting which have been well discussed here, but the methodology is applied consistently over time and its a useful tool for measuring aggregate temperature in the CAB, especially when results are corroborated by forecast models like GFS.

The correlation between the days of above average temperature per the weather models and the peak area losses is put out there for people to consider. If they want to reject the idea of causation, that's their business.

I'm not personally declaring a temperature peak. I'm just sharing the peak that the DMI and GFS models are showing.
« Last Edit: July 07, 2020, 11:28:14 PM by oren »

ArcTickTock

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Re: The 2020 melting season
« Reply #2361 on: July 07, 2020, 08:10:59 PM »
The physics principles of why DMI Arctic temps is pinned close to 0C near the surface is pretty clear but I also agree that the fluctuations are meaningful.  One year in the not too distant future there will likely be a trend to the highside that may break out into numbers never seen before.  If not a tipping point it will be at least a turning point signifying that enough melt has occurred in the CAB that the ice can no longer hold the temps consistently near the melting point across the central basin.  A very bad sign if and when it happens.

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Re: The 2020 melting season
« Reply #2362 on: July 07, 2020, 08:22:05 PM »
For what it's worth, I do notice on the nullschool runs today that the 850 mb temps are also slated to cool somewhat towards the end of this week (although still slated to be about 4C over the CAB on average, which is still bad enough to melt a lot of ice when combined with direct insolation).  It's possible the warm air aloft needs to be replenished by more hot rising air coming off the continents if the 850 mb layer wants to stay as warm as it has been. 

If the 850 mb temps are slated to drop from almost 10C to 4C, then it would only make sense for surface temps to drop from about 2C to just slightly above 0C.  There will still be melting...just not at as furious of a pace as it has been the past couple of days. 

So yes, I think the minor fluctuations in surface temp are meaningful, but probably not as meaningful as the 850 mb temps or the insolation. 

romett1

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Re: The 2020 melting season
« Reply #2363 on: July 07, 2020, 08:24:09 PM »
3-day average 10m wind speed forecast (GFS) - today's forecast vs Monday's forecast. Slightly less wind (but still a wind) over ESS and Laptev over the next three days. At the same time windy conditions continue over the area north of Svalbard and especially around Franz Josef Land.

gandul

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Re: The 2020 melting season
« Reply #2364 on: July 07, 2020, 08:31:38 PM »
An exciting issue this year will be the race of the Laptev bite to the North Pole to leave it bare of ice. Looking at the concentration maps, I bet it will.

Freegrass

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Re: The 2020 melting season
« Reply #2365 on: July 07, 2020, 08:32:34 PM »
Latest Five Day Forecast
Wind @ Surface

Large GIF!
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Re: The 2020 melting season
« Reply #2366 on: July 07, 2020, 08:50:59 PM »
The dome over the Arctic is continuously being injected with heat from lower latitude ridges so it seems it won’t fade out, rather it will leave the scene at the top of its 10-day career.

Freegrass

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Re: The 2020 melting season
« Reply #2367 on: July 07, 2020, 08:52:41 PM »
Latest Five Day Forecast
Wind @ Surface

Large GIF!
Are there any bets yet on the size of the mega crack after this little storm moves along the CAA and Greenland coast?
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pearscot

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Re: The 2020 melting season
« Reply #2368 on: July 07, 2020, 08:53:07 PM »
@grandul: I'm really interested in seeing what happens with that as well. If you look on worldview today a vast majority of the ice spanning to the pole is uninhibited by clouds.

@Freegrass: When is the weather supposed to ramp up for peak Fram export? Again, I think as the pack is now more mobile, as evidenced by the massive crack forming above Greenland/CAA, so I feel like this has the potential to act as an ice shaver - just pushing significant amounts south toward the Atlantic.

Lastly, I'll wait for the data to fully load before making a better post, but given last year was the first year I've ever seen a crack form above Greenland, what I'm already seeing now seems to indicate the damage done in 2019 and recently to the CAA is already having a profound effect. And comparing it to 2019 is nothing to take lightly...that was a robust year.
pls!

Pagophilus

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Re: The 2020 melting season
« Reply #2369 on: July 07, 2020, 09:10:03 PM »
Pagophilus, I'd rather this discussion take place in another thread. However a quick answer is needed to avoid misunderstandings by other readers.

Understood.  Will be more circumspect in future!  And thank you for the corrections.
« Last Edit: July 07, 2020, 09:16:35 PM by Pagophilus »
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Pagophilus

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Re: The 2020 melting season
« Reply #2370 on: July 07, 2020, 09:12:29 PM »
just play the next 2 days .. b.c.

"Pay it, Sam. Play 'as time goes by."

LMAO.   And about something extremely serious too.   
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Freegrass

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Re: The 2020 melting season
« Reply #2371 on: July 07, 2020, 09:23:46 PM »
@Freegrass: When is the weather supposed to ramp up for peak Fram export?
In winter?  ::)
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Re: The 2020 melting season
« Reply #2372 on: July 07, 2020, 09:35:32 PM »
Browned ice is simply vanishing in situ.
What makes the ice brown? You don't see that on thick ice, so is the ice so thin that the dirt (algae?) on the underside gets exposed? Or are those the remnants from black carbon that fell on the ice?

Freegrass, I believe the brown color of the thin ice is due to algae that grow inside or attached to the underside of the ice.  There are a variety of different species.

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Re: The 2020 melting season
« Reply #2373 on: July 07, 2020, 09:38:01 PM »
I took a couple of Worldview true color closeups from today and same date and location in 2012.  Approx location shown in red in the 3rd pic.  There was a bit of cloud and maybe fog in the 2012, but it certainly looks like 2020 melt ponding more extensive at this date. Is that a correct interpretation? Or was 2012 beyond bluing at this point and into the grey zone of drained meltponds?  Or just too cloudy or indistinct to be sure?

ArcTickTock

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Re: The 2020 melting season
« Reply #2374 on: July 07, 2020, 09:42:32 PM »
An exciting issue this year will be the race of the Laptev bite to the North Pole to leave it bare of ice. Looking at the concentration maps, I bet it will.

I would take that bet gandul, the Laptev bite may be a large one this year but it would be surprising to see it race all the way to the pole.    In the peripheral seas melting can happen till Sep but would have to think time runs out quickly on insolation at NP and not sure the bite would have enough time to raise local SSTs for bottom melt so far in.  If your bet is correct it would be huge news though!

Freegrass

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Re: The 2020 melting season
« Reply #2375 on: July 07, 2020, 09:43:01 PM »
Browned ice is simply vanishing in situ.
What makes the ice brown? You don't see that on thick ice, so is the ice so thin that the dirt (algae?) on the underside gets exposed? Or are those the remnants from black carbon that fell on the ice?

Freegrass, I believe the brown color of the thin ice is due to algae that grow inside or attached to the underside of the ice.  There are a variety of different species.
I think so too, but I'm also wondering if those algae wouldn't have "washed off" by now through bottom melt.

Could it be waves washing over the ice and depositing those algae on top?

Edit: Or dirt (black carbon) washing off the top of the ice feeding an algae bloom that ends up mingled with the ice?


Edit 2: If it were algae that show through thin ice, then why is this big (10km) floe also brown? Another one is whiter, but they're both big, and thus must be thick. So the only explanation IMHO is that something ended up on top of that large floe. But how can waves wash up over an entire 10km ice floe? So it must be black carbon from the fires, no?


Dirty rain?
« Last Edit: July 07, 2020, 10:21:09 PM by Freegrass »
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grixm

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Re: The 2020 melting season
« Reply #2376 on: July 07, 2020, 09:52:48 PM »
We haven't seen a photo of the laptev from under the clouds for a while, I really want to see how it looks by now.

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Re: The 2020 melting season
« Reply #2377 on: July 07, 2020, 10:38:30 PM »
With regards to Judah Cohen's recent post, very high sea surface temperatures and ocean heat contents in the northern Indian ocean, Indonesian seas, and far western Pacific are causing excessive rains in eastern Asia and are stalling the progression of the Madden- Julian oscillation out of the Indian ocean - Indonesian sectors.  When the MJO gets stuck so can weather patterns in the rest of the northern hemisphere because the tropical convection that the MJO centers around is an enormous heat engine that is transferring heat from the overheated ocean to the upper atmosphere.

Global weather patterns are tied into the MJO phase. This is one reason the ridge-trough pattern over Asia has been stuck and that ties in with the ridging in the Arctic.

Note also that his point about intensifying temperature gradients between the ice and warming oceans apply both the Arctic ocean and the subarctic seas on the Atlantic side. The high over the pole has been coupled with the low in the Greenland sea. Greenland's ice cap is the cold side of an increasingly intense temperature gradient in the north Atlantic.

The map below shows a forecast  huge anomalous upwelling over the Indonesian region in August. The MJO will continue to be stuck according to the CFS model.

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Re: The 2020 melting season
« Reply #2378 on: July 07, 2020, 10:39:11 PM »

OK...what is epic about the 10 day forecast? I see a temp forecast at 850 hpa. Google tells me this is generally about 1.5km above sea level, above the boundary layer.


I seem to recall from my Meteorology course at Uni (a long time ago!) that subsidence in an anticyclone is of the order of 2 or 3 cm per second. That would mean air at 1.5km would reach the surface in under a day. With a dry adiabatic lapse rate of around 10 deg C/km, then all other things being equal, the air at 850 hpa would warm by around 15 deg C. Obviously other factors are at play, but am I missing something?

Pagophilus

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Re: The 2020 melting season
« Reply #2379 on: July 07, 2020, 10:42:30 PM »
Latest Five Day Forecast
Wind @ Surface

Large GIF!

Great to see the continuous projected action.  Thank you.  Will that intense little cyclonic system coming in from bottom right jam any Fram export for a bit?
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Freegrass

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Re: The 2020 melting season
« Reply #2380 on: July 07, 2020, 10:50:54 PM »
Latest Five Day Forecast
Wind @ Surface

Large GIF!

Great to see the continuous projected action.  Thank you.  Will that intense little cyclonic system coming in from bottom right jam any Fram export for a bit?
I think a lift of the pack (mega crack) could free up the pressure on the lincoln plug, causing it to flow more freely through the Fram.

But that's just the opinion of a fat guy behind a computer who has no idea what he's talking about...  ;)
« Last Edit: July 07, 2020, 11:10:07 PM by oren »
If every 8 year old in the world is taught meditation, we will eliminate violence from the world within one generation.
-The Dalai Lama

Did you know that Jesus was thought to be the reincarnation of a Buddhist monk?
Where do you think the three wise men came from?
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Phoenix

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Re: The 2020 melting season
« Reply #2381 on: July 07, 2020, 11:08:10 PM »
Check out the GFS temperature forecast for the next 10 days.

Look at the sub zero temperatures in the Beaufort, Chuckchi and ESS from July 11th - 17th.

https://climatereanalyzer.org/wx/fcst/#gfs.arc-lea.t2

The high pressure is doing a fantastic job of keeping the infernal Siberian WAA away from the ice.

<Edited out the inflammatory CAPS nonsense. O>
« Last Edit: July 08, 2020, 02:32:39 AM by oren »

gandul

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Re: The 2020 melting season
« Reply #2382 on: July 07, 2020, 11:21:52 PM »
Sub zero may still mean melting for sure. That's your summer temp over the Arctic ocean. What was extreme is seeing 2m over zero temps sustained well into the CAB for days.

gandul

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Re: The 2020 melting season
« Reply #2383 on: July 07, 2020, 11:27:44 PM »
Storms entering and leaving the Arctic is the worst the thinned and fragile ice can now get, dispersion, enhanced bottom melt...
Bring some snow if you wish.
Boredom, stalled weather, especially central moderate cold low, is what could bring the break to the melting season.
But I don't see that in the forecast yet.

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Re: The 2020 melting season
« Reply #2384 on: July 07, 2020, 11:48:42 PM »
Starting to see some real unclogging of the channels in the CAA now.
Click It!!
« Last Edit: July 07, 2020, 11:54:14 PM by Tigertown »
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Re: The 2020 melting season
« Reply #2385 on: July 07, 2020, 11:52:29 PM »
Check out the GFS temperature forecast for the next 10 days. I'm not big on CAPS, but this is GLORIOUS !!

Look at all the beautiful ice saving BLUE sub zero temperatures...

The forecast is horrific for "saving ice".

Edit: speaking of Phx, the city in AZ USA will have a MEAN mean-temp of 100F over the next ten days.
big time oops

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Re: The 2020 melting season
« Reply #2386 on: July 07, 2020, 11:59:30 PM »

Look at all the beautiful ice saving BLUE sub zero temperatures in the Beaufort, Chuckchi and ESS from July 11th - 17th.

https://climatereanalyzer.org/wx/fcst/#gfs.arc-lea.t2

The high pressure is doing a fantastic job of keeping the infernal Siberian WAA away from the ice.

While the GFS 12Z from today does show cooler air coming into the CAA, Beaufort and eastern Chukchi from D3-10, that's pretty much it until after D10 (w/r/t 850mb). The rest of the arctic is dominated by WAA, and the total temp anomaly at 2m is pretty consistently averaging around 1C above normal during this period. From my perspective this is forecasting just slightly better overall conditions for the ice than what we're seeing right now, which is horrendous. As the high weakens around d6-7, warm air floods into the ESS, Laptev, western Chukchi and adjacent CAB. Prior to that there is significant positive temp anomalies associated with the HP (1st image).

I'm curious as to why you ignored all of this in favor of that you just posted? Were you just not aware? It just seems to me like your post is rather imbalanced and out-of-context.
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marcel_g

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Re: The 2020 melting season
« Reply #2387 on: July 08, 2020, 12:16:13 AM »
So, as a non-expert, let me see if I have got this straight...  (and my mistakes, if corrected, may help illuminate matters for some other Frazilers)

The current anticyclone over the pole looks set to compact the ice and warm the Arctic generally.
 
a. It will compact the ice pack by 'pulling' ice inwards (really the Coriolis Effect), probably producing much more open water in the Chukchi, ESS and Laptev, and maybe in the Beaufort too.  This is already happening.

b. The extra areas of exposed seawater will then soak up a whole lot of near-maximum 24/7 Arctic insolation, warming their surface waters.  The warm water will remain at the surface because of its low density.  (Upwelling may also occur in places, bringing warm, saline water to the surface in places.)  All this seems probable, especially with the forecast clear skies.

d. Compaction will probably make for dramatic extent losses, but not necessarily in and of itself be terrible for the ice in terms of ice volume, since overall melting will be reduced when all the ice is together.

The rest is more speculative.  Anything can happen and has happened during melting seasons, producing far different results than anticipated at the time.  But here is a plausible scenario which I think many have been explicitly or implicitly discussing:

What would be a really bad sequel is, IF , after all this compaction of ice and warming of surrounding water has occurred, storms/cyclonic/dipole systems enter the Arctic region. Such events would not only bring in atmospheric heat, but also, more importantly, disperse the compacted ice into the newly warmed surrounding seas (Laptev, ESS etc).  In this situation, ice would melt rapidly, because the heat transfer from surrounding water is generally more destructive to ice than heat transfer from the air.  At this point, it might not matter much if the weather is cloudy or not.

I know there are many factors missing here (ocean currents etc) ... I welcome corrections if anyone has the time and look forward to learning more...

I’m still working my way through today’s posts, so my apologies if someone else has answered this in the meantime.

AFAIK, one of the most important things you’ve missed is the effect of preconditioning: the wet ice, with low albedo is not just absorbing energy and warming ice and melting off the top, much of the solar energy that would be reflected by snow is passing right through the ice and warming the water under neath it. This effect won’t be immediately visible, and how much energy got into the water will show up in August, as too melt slows and bottom melt continues. As well, any open water and wave action will bring this latent heat up to the ice as well.

Phoenix

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Re: The 2020 melting season
« Reply #2388 on: July 08, 2020, 01:01:43 AM »

While the GFS 12Z from today does show cooler air coming into the CAA, Beaufort and eastern Chukchi from D3-10, that's pretty much it until after D10 (w/r/t 850mb). The rest of the arctic is dominated by WAA, and the total temp anomaly at 2m is pretty consistently averaging around 1C above normal during this period. From my perspective this is forecasting just slightly better overall conditions for the ice than what we're seeing right now, which is horrendous. As the high weakens around d6-7, warm air floods into the ESS, Laptev, western Chukchi and adjacent CAB. Prior to that there is significant positive temp anomalies associated with the HP (1st image).

I'm curious as to why you ignored all of this in favor of that you just posted? Were you just not aware? It just seems to me like your post is rather imbalanced and out-of-context.

Oren wants us to focus on the importance of 850 hpa temps vs. surface temps in a different thread. I'm focusing on posting 2m temps which make more sense to me than temps a mile above the surface.

If the forecast holds, we're going to get heaps of anecdotal evidence in the coming week or two as to how the ice holds up when the surface is relatively cold and the temp way up in the sky isn't. Let's check back in then.

<Oren Wants you to stop derailing this thread with inflammatory posts that ignore accepted science. O>
« Last Edit: July 08, 2020, 02:31:55 AM by oren »

bbr2315

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Re: The 2020 melting season
« Reply #2389 on: July 08, 2020, 01:07:29 AM »

While the GFS 12Z from today does show cooler air coming into the CAA, Beaufort and eastern Chukchi from D3-10, that's pretty much it until after D10 (w/r/t 850mb). The rest of the arctic is dominated by WAA, and the total temp anomaly at 2m is pretty consistently averaging around 1C above normal during this period. From my perspective this is forecasting just slightly better overall conditions for the ice than what we're seeing right now, which is horrendous. As the high weakens around d6-7, warm air floods into the ESS, Laptev, western Chukchi and adjacent CAB. Prior to that there is significant positive temp anomalies associated with the HP (1st image).

I'm curious as to why you ignored all of this in favor of that you just posted? Were you just not aware? It just seems to me like your post is rather imbalanced and out-of-context.

Oren wants us to focus on the importance of 850 hpa temps vs. surface temps in a different thread. I'm focusing on posting 2m temps which make more sense to me than temps a mile above the surface.

If the forecast holds, we're going to get heaps of anecdotal evidence in the coming week or two as to how the ice holds up when the surface is relatively cold and the temp way up in the sky isn't. Let's check back in then.
HYCOM has problems but I think it is correct here. The Beaufort and Chukchi are hardly under days of sub-0C temps. The EURO also has extent in the Chukchi plummeting and concentration taking a major hit in the Beaufort. With all the red herrings you are creating we may no longer have to worry about plunging global fish stocks.

Beaufort and Chukchi are almost entirely FYI that is now 30-45 days from melting out entirely.


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Re: The 2020 melting season
« Reply #2390 on: July 08, 2020, 02:14:48 AM »
Check out the GFS temperature forecast for the next 10 days. I'm not big on CAPS, but this is GLORIOUS !!

Look at all the beautiful ice saving BLUE sub zero temperatures in the Beaufort, Chuckchi and ESS from July 11th - 17th.

https://climatereanalyzer.org/wx/fcst/#gfs.arc-lea.t2

The high pressure is doing a fantastic job of keeping the infernal Siberian WAA away from the ice.

A lot of that blue is over what is or will be open water by seasons end so not sure how comforting this is!  Might want to switch to 2m anomaly, that seems more instructive.  With that setting there is a lot of anomalous heat attacking the pole via Laptev bite.  I believe in not dismissing any data sources as a measure of truth can be gleaned from all data sources and particularly by blending from multiple sources.  That said there are patterns of change and absence of change that are eyebrow raising in the climate reanalyzer that look questionable.  Does the Chukchi really have such a fixed pattern when turbulent change is all around it?  The patterns around Hudson Bay and Labrador look hmmm as well!  It is at 2 meter so I can almost believe some of these patterns, almost.

FishOutofWater

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Re: The 2020 melting season
« Reply #2391 on: July 08, 2020, 03:30:43 AM »
Phoenix, you are being intentionally obtuse. Hard inversions above the ice under a subsidence high trap solar energy. Arguing the details of 850 temperatures vs surface temperatures is irrelevant because in early July the energy of insolation is dominant under clear skies.

Arctic ocean air temperature forecasts beyond a few days are unreliable.

The reason that the transition to a blue Arctic ocean is slow is that the melting season is short and thermal inertia is large. The ice is "saved by the bell".  This summer there is strong "melting momentum" which is being brought on by the build up of heat under melt ponds caused by days on end of direct insolation. This weather is not good for the ice.

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Re: The 2020 melting season
« Reply #2392 on: July 08, 2020, 03:38:32 AM »
Starting to see some real unclogging of the channels in the CAA now.
Cycling through past years since 2012, this year is the first year where all the fast ice has broken in the Wellington Channel by this date. The main channel breakup is as advanced as several other years, but was much more advanced in 2017.
Click to animate.


GoSouthYoungins

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Re: The 2020 melting season
« Reply #2393 on: July 08, 2020, 03:58:17 AM »
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Michael Hauber

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Re: The 2020 melting season
« Reply #2394 on: July 08, 2020, 04:18:19 AM »
I took a couple of Worldview true color closeups from today and same date and location in 2012.  Approx location shown in red in the 3rd pic.  There was a bit of cloud and maybe fog in the 2012, but it certainly looks like 2020 melt ponding more extensive at this date. Is that a correct interpretation? Or was 2012 beyond bluing at this point and into the grey zone of drained meltponds?  Or just too cloudy or indistinct to be sure?

2012 was generally more disperse.  And while dispersion isn't really evident in the particular spot you've chosen I suspect it may be a case of broken up floes jammed closely together vs this year a more continuous sheet - appearance of long crack type features suggests more continuous ice.  So this year would hold more melt ponds.  Also this year is generally much hotter at the current time.  2012 was hot earlier with pretty much the earliest onset of general melt ponding in the record (although I didn't watch this year closely and haven't made a detailed comparison).  The theme on the arctic forum about this time in 2012, definitely by late July was how come the ice stats continue to crash despite cooler cloudy conditions (relative to 2011 and 2010)

Seems reasonable that there is more surface ponding than in 2012, for a variety of reasons, and also that 2012 melted more from below or the side - my theory being that sunlight pouring into open water in between the floes was a huge factor, and many others believing the GAC pulling heat from below was the big reason.

I like to look at channel 3-6-7 to asses melt ponding - more water shows up as a deeper red, and clouds are very distinct, although when thin cloud is present it is harder to see the ice below than in natural colour.
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Phoenix

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Re: The 2020 melting season
« Reply #2395 on: July 08, 2020, 05:28:05 AM »
Phoenix, you are being intentionally obtuse. Hard inversions above the ice under a subsidence high trap solar energy. Arguing the details of 850 temperatures vs surface temperatures is irrelevant because in early July the energy of insolation is dominant under clear skies.

Arctic ocean air temperature forecasts beyond a few days are unreliable.

The reason that the transition to a blue Arctic ocean is slow is that the melting season is short and thermal inertia is large. The ice is "saved by the bell".  This summer there is strong "melting momentum" which is being brought on by the build up of heat under melt ponds caused by days on end of direct insolation. This weather is not good for the ice.
Current conditions slightly better for the ice than two days ago, IMO.

There are factors which bode poorly for the ice and factors which offset those.

There were 750 km3 more ice in the Arctic per PIOMAS on 6/30 this year vs. last year. The Beaufort Sea is in way better condition than expected. Nico Sun's site tells us that the accumulated AWP anomaly in the CAB is neutral for the season as a whole. Historical data tells us that typical export in the summer is de minimis. The full story involves more than just the pro hi-melt factors.

If I see a forecast with some negative surface temperatures, I share it because I genuinely believe that it's better than a forecast with positive surface temperatures.

<Massively edited and shortened. Discuss the ice, not yourself. Avoid repetitions. O>
« Last Edit: July 08, 2020, 06:25:08 AM by oren »

Rod

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Re: The 2020 melting season
« Reply #2396 on: July 08, 2020, 05:44:03 AM »
Phoenix, you are being intentionally obtuse.

When FOW calls someone out, you know things are bad! He is the nicest guy on the planet. 😂😂😂

Rod

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Re: The 2020 melting season
« Reply #2397 on: July 08, 2020, 05:52:31 AM »
Some nice maps from Zack today that help to explain the crazy low amounts of ice we are seeing along the Russian coast.

tzupancic

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Re: The 2020 melting season
« Reply #2398 on: July 08, 2020, 06:01:32 AM »
Browned ice is simply vanishing in situ.
What makes the ice brown? You don't see that on thick ice, so is the ice so thin that the dirt (algae?) on the underside gets exposed? Or are those the remnants from black carbon that fell on the ice?

Freegrass, I believe the brown color of the thin ice is due to algae that grow inside or attached to the underside of the ice.  There are a variety of different species.
I think so too, but I'm also wondering if those algae wouldn't have "washed off" by now through bottom melt.

Could it be waves washing over the ice and depositing those algae on top?

Edit: Or dirt (black carbon) washing off the top of the ice feeding an algae bloom that ends up mingled with the ice?


Edit 2: If it were algae that show through thin ice, then why is this big (10km) floe also brown? Another one is whiter, but they're both big, and thus must be thick. So the only explanation IMHO is that something ended up on top of that large floe. But how can waves wash up over an entire 10km ice floe? So it must be black carbon from the fires, no?


Dirty rain?

Freegrass, those are great questions, but even though the brown discoloration seen in thin, melting ice would appear to decrease albedo and be quite relevant to the melting season thread, I kind of think that getting into the details of sea ice algae biology would be seen as 'off topic' regardless of the extent to which it is actually relevant. Nevertheless, it does appear that most, if not all of the coloration of the thin, melting ice is due to algae. How they stay there as bottom melt occurs is a great question, since it would appear to be a significant factor affecting albedo. 

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Re: The 2020 melting season
« Reply #2399 on: July 08, 2020, 06:12:48 AM »
I’m not sure it is off topic if it affects melting. We have had this discussion in previous years.

If I remember correctly, A-Team addressed it at one point. Algae is certainly one component of the discoloration.  However, sediment and soot are other potential causes. We see the discolored ice in the Chukchi every year. We also see it in Foxe Basin, where we know it is from sediment.

Just speaking anecdotally, I am always surprised each year at how long it takes the “dirty” ice to melt.