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Paul

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Re: The 2019 melting season
« Reply #3050 on: July 02, 2019, 12:39:30 AM »
Current MODIS view.  Lots of clouds keeping things cooler.  No dispersion visible in the gaps except in Beaufort.  Dispersion exists all along the fringes.



Same day 2012.  Much more dispersion visible.  Partly because there were less of those cooling clouds.  But the circled area has substantial areas of somewhat dispersed ice.  Through the melting season this ice kept getting worse and worse and eventually melts out completely.  I have seen no evidence of anything like like this large area of partially dispersed ice deep within the pack in the gaps between the clouds on the Russian side.  There is some of this dispersion penetrating deep into the pack in the Beaufort area but it is a small area compred to what happened in 2012 on the Russian side.



And imo, this is the one thing that is making me question whether a record low will happen this year or not but whilst there seems to be little dispersion in that area you highlighted, the ice does have a greyish colour and the breman charts do show slightly lower concentration in that area.

I hope no one will brand you a troll for your post, there is nothing wrong with bringing a bit of balance to this thread and what you state is true.

bbr2314

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Re: The 2019 melting season
« Reply #3051 on: July 02, 2019, 12:45:15 AM »
Super convenient that clouds are covering all the OPEN WATER in 2019 that is extra relative to 2012 in Hauber's single shot.

Neven

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Re: The 2019 melting season
« Reply #3052 on: July 02, 2019, 12:51:36 AM »
I hope no one will brand you a troll for your post, there is nothing wrong with bringing a bit of balance to this thread and what you state is true.

Balancing what exactly? The situation is looking very bad, right now. This may change in coming weeks, but right now, the situation looks very bad. Why would that need to be balanced? Practically nobody is saying that 2019 is guaranteed to break records, come September. All we know right now is that it is possible that 2019 breaks records. If you want to balance that, you have to say: It's impossible that 2019 will break records.

If that's the kind of balance you are looking for, you need to compliment weatherdude88.

I agree that it is good to compare 2019 to 2012, especially if things keep going the way they are. But Michael isn't really saying anything, is he? He's just implying something along the lines of 'it's not so bad'. It has nothing to do with balance.
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jdallen

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Re: The 2019 melting season
« Reply #3053 on: July 02, 2019, 12:52:40 AM »
 Wouldn't cheer yet.  There is 2-3cm of rain forecast to fall under a bunch of these clouds on the Pacific side.
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petm

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Re: The 2019 melting season
« Reply #3054 on: July 02, 2019, 01:03:17 AM »
Same day 2012.

To compare ice patterns from visible wavelength photographs, you ought to compare a day from each year that is relatively cloud free, rather than cherry picking one from this year that is relatively cloudy. There have been many in the last few weeks to choose from. This is what most people do, who want to provide useful observations rather than pushing an agenda.

Balancing what exactly?

+1

https://en.wikipedia.org/wiki/False_balance

Pagophilus

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Re: The 2019 melting season
« Reply #3055 on: July 02, 2019, 01:14:15 AM »
June 26-30.

2018.

Thanks once more, Aluminium.  Your gifs show what cannot be adequately seen on Worldview (because of clouds). 

What strikes me is that the forecast strong Fram export is actually occurring apace (and is forecast to continue for three days or so).  That adds up to a lot of ice leaving the CAB.  Much of it MYI.

In addition, the whole Atlantic side now seems be be shrinking back rather alarmingly.   
« Last Edit: July 02, 2019, 02:29:01 PM by Pagophilus »

wallen

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Re: The 2019 melting season
« Reply #3056 on: July 02, 2019, 01:15:00 AM »
End of June set up 2019/2016/2007 comparison, unfortunately, 2012 data missing.
One big difference is that the Beaufort polyna disappeared very early this year. Have got to wonder what impact this may have as the seasom progresses.

Michael Hauber

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Re: The 2019 melting season
« Reply #3057 on: July 02, 2019, 01:15:09 AM »
Balanced:  someone who is willing to discuss and acknowledge both the reasons why melt might be high, such as the recent heatwave, which was certainly extreme.  And willing to discuss reasons that the melt might not be as high, such as current lack of dispersion, and less extreme heat and increased cloudiness currently occurring and likely to continue in the short term forecast window. 

Unbalanced:  someone who can only discuss the reasons why melt will be high and accuses anyone who brings up any reasons why melt might be reduced of being a troll.
Climate change:  Prepare for the worst, hope for the best, expect the middle.

Michael Hauber

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Re: The 2019 melting season
« Reply #3058 on: July 02, 2019, 01:17:03 AM »
the ice does have a greyish colour and the breman charts do show slightly lower concentration in that area.


Yes lots (possibly unprecedented) of melt ponding and surface melt going on.
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Michael Hauber

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Re: The 2019 melting season
« Reply #3059 on: July 02, 2019, 01:23:41 AM »

To compare ice patterns from visible wavelength photographs, you ought to compare a day from each year that is relatively cloud free, rather than cherry picking one from this year that is relatively cloudy.

Maybe I'm being overly cynical, but if I picked a date from a few days ago where it wasn't cloudy someone would have complained I was trying to hide something by not showing current data.  The data is quite easy to access to check alternate dates and see if they show something different to what I am claiming.
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abraca

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Re: The 2019 melting season
« Reply #3060 on: July 02, 2019, 01:24:45 AM »
Hello, can you look at
https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2019-06-29-T00%3A00%3A00Z&z=3&v=-835137.1514222269,-920779.3466764247,-507457.1514222269,-748875.3466764247&ab=on&as=2019-06-28T00%3A00%3A00Z&ae=2019-07-01T00%3A00%3A00Z&av=3&al=true

it's part of CAA. It was the bluest fast ice I could see. The ponds must have been deep there. And a few days ago it started to be infected by some growing white thing (run animation). Guess it's not much freezing, at around 0-7deg C, and it started from shores and older cracks. Is it pond draining before it disappear maybe then?

petm

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Re: The 2019 melting season
« Reply #3061 on: July 02, 2019, 01:33:54 AM »

To compare ice patterns from visible wavelength photographs, you ought to compare a day from each year that is relatively cloud free, rather than cherry picking one from this year that is relatively cloudy.

Maybe I'm being overly cynical

So your defense to trolling is that if you didn't do it you'd be accused of it? Hats off! I can see you're not new to this game.

Michael Hauber

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Re: The 2019 melting season
« Reply #3062 on: July 02, 2019, 01:36:58 AM »

So your defense to trolling is that if you didn't do it you'd be accused of it? Hats off! I can see you're not new to this game.

Do you have some useful facts or data to bring to the discussion?  Like a date and region which shows where I am wrong about 2019 being more dispersed than 2012?  Or do you only have insults?

Try 2012  vs 2019 from the 27th of June.
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Sterks

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Re: The 2019 melting season
« Reply #3063 on: July 02, 2019, 01:41:27 AM »
This is over the CAB right north of the Beaufort sea
The low causes surface wetting as revealed by the 7 2 1 false color image, now high pressure, clear skies and warmth takes over
https://go.nasa.gov/326OEjc

petm

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Re: The 2019 melting season
« Reply #3064 on: July 02, 2019, 01:50:21 AM »
And a few days ago it started to be infected by some growing white thing (run animation).

Cool observation, thanks for sharing it. I don't know, but one guess would be pooling of runoff from the snow (and glaciers?) melting on the mountains above, which is also visible. That would be consistent with the pattern of movement of the "white thing", first filling the shore-adjacent areas especially below valleys, then filling cracks, which are lower than surrounding ice. I'm not sure why the color would be different -- possibly the melt water freezes on contact with the sea ice due to lower salinity, or more likely that's just the color of runoff e.g. due to sediment.

If it is melt water, it would be a transfer of heat from the adjacent land to the sea ice.

But hopefully someone else has a more expert answer.
« Last Edit: July 02, 2019, 02:04:37 AM by petm »

petm

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Re: The 2019 melting season
« Reply #3065 on: July 02, 2019, 01:54:23 AM »
Do you have some useful facts or data to bring to the discussion?

Yeah, I do so almost every day. Do you?

subgeometer

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Re: The 2019 melting season
« Reply #3066 on: July 02, 2019, 02:14:29 AM »
It may not change anything but the gfs forecast has Ellesmere island over !6'C today and above 12'C seemingly constantly for the next 7 days . Next door the N. of Greenland is enjoying a balmy 8'C for the week .
Meanwhile the lowest 850hpa temps in the N.hemisphere are over the Faroes and Shetland ( where my auntie Maureen will be 90 tomorrow :)  ). There is no cold air in the Arctic or over Greenland ! .. b.c.
[/b]
Warmth has spread across the CAA over the past few days and all without a cloud in the sky. And with no snow left except on the heights, so all the land between the channels can warm up considerably

This is contrary to EC/ Windy, which still has most lower areas of Ellesmere etc snowy, as well as the largest island in the Laptev, which lost all its snow a couple of weeks ago, but Windy still shows it covered in 4.74m of deep snow - odd, as it seems quite reliable otherwise, maybe there's no physical data to update the model for these spots, though in the Laptev (most of) the adjacent islands are correctly shown snowfree, so there's a bit of a bug. How much effect this has locally on the forecast I don't know, the spot with 4.68m in Ellesmere sits around 5-10C all week yet actually increases fakesnow depth by week's end after initially losing a few cm

subgeometer

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Re: The 2019 melting season
« Reply #3067 on: July 02, 2019, 02:18:32 AM »
Wouldn't cheer yet.  There is 2-3cm of rain forecast to fall under a bunch of these clouds on the Pacific side.

In the second half of the GFS runs today, the amount of precipitable moisture circulating in the Pacific half without much rain that blows me out, it's like a humid week in the subtropics

Michael Hauber

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Re: The 2019 melting season
« Reply #3068 on: July 02, 2019, 02:38:05 AM »
Do you have some useful facts or data to bring to the discussion?

Yeah, I do so almost every day.

I meant the current discussion about how much dispersed ice there is at the moment.  Seems the answer is no

Do you?

I think the fact that the ice is currently less dispersed than 2012 is a useful fact.
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subgeometer

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Re: The 2019 melting season
« Reply #3069 on: July 02, 2019, 02:49:19 AM »
Recent lack of dispersion Michael Hauber?

Excuse me, but What?

What is the stream of CAB ice being pumped into the Beaufort Sea? That's just one example. ESS extent bouncing, dead cat style, as the fast ice disiintegrates. A reversal of wind pushing ice into the Laptev Bite

And the elephant in the room, Atlantic export. As the WeatherDude so acutely observed, the CAB extent is high. Why?, the Atlantic exits are loaded with thick ice. The Barents Sea is very high, having been fed by that full, dispersing, CAB. The Greenland Sea is also high, it jumped ~100k this week, also from the CAB. That's a pyrrhic "gain" in extent.

Nevertheless extent dropped 400K on JAXA over the past 4 days, remaining close to record low, area is record low, we await the volume numbers


petm

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Re: The 2019 melting season
« Reply #3070 on: July 02, 2019, 03:02:13 AM »
I think the fact that the ice is currently less dispersed than 2012 is a useful fact.

If you think that's a "fact", that's up to you. I prefer to evaluate the world in terms of weighing evidence; i.e., scientifically. And I don't see much evidence for your claim, other than that you eyeballed one region of a pair of quite likely cherry-picked photographs and stated a subjective judgement. I also seem to recall you claiming that dispersion was not taking place a few weeks back, when storms in the Beaufort very clearly reversed a compaction trend and spread ice out from a region of high concentration north of the CAA into the then open waters of the Beaufort. So I'm personally not inclined to place a lot of weight on your subjective judgements about dispersion.

jdallen

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Re: The 2019 melting season
« Reply #3071 on: July 02, 2019, 03:14:48 AM »
 Hmmm.  Would Wipneus' data let us calc regional CAPIEs?
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Paul

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Re: The 2019 melting season
« Reply #3072 on: July 02, 2019, 03:18:18 AM »
I hope no one will brand you a troll for your post, there is nothing wrong with bringing a bit of balance to this thread and what you state is true.

Balancing what exactly? The situation is looking very bad, right now. This may change in coming weeks, but right now, the situation looks very bad. Why would that need to be balanced? Practically nobody is saying that 2019 is guaranteed to break records, come September. All we know right now is that it is possible that 2019 breaks records. If you want to balance that, you have to say: It's impossible that 2019 will break records.

If that's the kind of balance you are looking for, you need to compliment weatherdude88.

I agree that it is good to compare 2019 to 2012, especially if things keep going the way they are. But Michael isn't really saying anything, is he? He's just implying something along the lines of 'it's not so bad'. It has nothing to do with balance.

The balance imo is that despite all the heat and energy, the ice pack over the Cab region is not full of holes like it was in 2016 and 2012 which may of played a factor in those years having lower minimum. It definitely played a part in the condition of the ice in 2016 where it was very diffused right towards the pole. Of course a diffused ice pack does not always mean a low minimum as 2013 showed but if 2013 was a warmer melt season in July and August, the results may of been different given how disperse the ice was quite early in that melt season.

I guess this melt season may test what is worse for the ice long term, dispersion or melt ponding? Of course, the big ace up the sleeve for this year is the SSTs and that well could have a massive part to play come late August and early September.

Pragma

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Re: The 2019 melting season
« Reply #3073 on: July 02, 2019, 03:30:52 AM »
I'm slowly figuring out how to drive and interpret various products, and frankly I don't see anything optimistic in the next week. I welcome any honest critique of my analysis.

-There are steady winds out of the CAB towards Fram from a triangle bounded by the pole, Svalbard and FJL. This has been ongoing, as can be seen by the low concentration stripes fanning out northward from Fram on the NSIDC daily snapshot. A pyrrhic extent gain indeed. There are also sustained winds down through Nares. Further west, winds are pushing the ice towards the Beaufort gyre and into the warm flow from the Bering. There seems to be a push to get out any ice north of 80.

- The CAA is warming up, with ridiculous temperatures coming to the northern edge of the mainland, and clear skies in the whole area.

- Meanwhile, there are warm, moist winds coming in over the Bering, depositing significant rain on the Russian side, and towards the CAB.

Only a week ago, the 2012 concentration map showed the ice to be far more dispersed than 2019, but that gap has almost closed.

I wouldn't be surprised to see the anomalous ice on either side of FJL vanish soon, due to both temperature and winds as well as Hudson and Baffin bay.

So, what's not to like? :-\

*Edit* typo  CAB towards Fram, not CAA.
« Last Edit: July 02, 2019, 05:44:19 AM by Pragma »

jdallen

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Re: The 2019 melting season
« Reply #3074 on: July 02, 2019, 03:47:06 AM »

The balance imo is that despite all the heat and energy, the ice pack over the Cab region is not full of holes like it was in 2016 and 2012 <snippage>

I'm not sure that's true, and highly doubtful any single factor like that made a difference.

I've included a couple of archived Bremen concentration maps (earliest I could get for July was the 23rd), and as you can see, 2012 and 2016 don't appear definitively "holier" than 2019; at least from what I can tell. (edit - though 2019 has a lot more purely open water.)
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FishOutofWater

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Re: The 2019 melting season
« Reply #3075 on: July 02, 2019, 04:03:41 AM »
Do you have some useful facts or data to bring to the discussion?

Yeah, I do so almost every day.

I meant the current discussion about how much dispersed ice there is at the moment.  Seems the answer is no

Do you?

I think the fact that the ice is currently less dispersed than 2012 is a useful fact.

It isn't a fact and it isn't useful as an indicator of the rest of the melting season. Early high melt pond extent has been shown in the scientific literature to be a good indicator of a low September extent. As far as I know, there's no literature showing dispersion is. If you can cite the literature, do it now. Otherwise, STFU.

petm

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Re: The 2019 melting season
« Reply #3076 on: July 02, 2019, 04:28:39 AM »
I've included a couple of archived Bremen concentration maps (earliest I could get for July was the 23rd), and as you can see, 2012 and 2016 don't appear definitively "holier" than 2019; at least from what I can tell. (edit - though 2019 has a lot more purely open water.)

While I agree that July 1st 2016 isn't obviously more 'hole-ie' than this year is, from first glance at those attachments, 2012 *does* seem a lot 'holier'. But of course the images are 3 weeks apart, during maximum melt. (Too bad the archive doesn't go back farther!) Looking at the 3rd week of July, 2016 (July 17 att.) does look similar in terms of CAB 'holie-ness' to 2012 (although other differences are apparent such as more ice on the Russian side in 2016 vs. 2012).

(Also note that this was just prior to the GAC of 2012, which began on Aug. 2:
https://en.wikipedia.org/wiki/Great_Arctic_Cyclone_of_2012 .)
« Last Edit: July 02, 2019, 04:33:53 AM by petm »

Retron

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Re: The 2019 melting season
« Reply #3077 on: July 02, 2019, 05:36:23 AM »
I've included a couple of archived Bremen concentration maps (earliest I could get for July was the 23rd), and as you can see, 2012 and 2016 don't appear definitively "holier" than 2019; at least from what I can tell. (edit - though 2019 has a lot more purely open water.)
Here's the Bremen map for the 3rd July 2012.

wdmn

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Re: The 2019 melting season
« Reply #3078 on: July 02, 2019, 05:45:29 AM »
The CAB CAA crack persists and grows.

Nullschool now shows a small positive STTA developing there, and tealight's albedo warming potential shows a small positive anomaly.

I am posting about it because there was some doubt expressed in mid-June that such a crack could/would remain open.


Rich

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Re: The 2019 melting season
« Reply #3079 on: July 02, 2019, 06:18:16 AM »
The CAB CAA crack persists and grows.

Nullschool now shows a small positive STTA developing there, and tealight's albedo warming potential shows a small positive anomaly.

I am posting about it because there was some doubt expressed in mid-June that such a crack could/would remain open.

The wind seems to dominate the ebb and flow of the crack. For the time being and the next few days, the wind forecast is pushing the pack away from the coast.

jdallen

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Re: The 2019 melting season
« Reply #3080 on: July 02, 2019, 06:55:58 AM »
I've included a couple of archived Bremen concentration maps (earliest I could get for July was the 23rd), and as you can see, 2012 and 2016 don't appear definitively "holier" than 2019; at least from what I can tell. (edit - though 2019 has a lot more purely open water.)
Here's the Bremen map for the 3rd July 2012.
Brilliant!  Thank you!

I think it does bear me out; I don't think either year was particularly more dispersed than we are currently; the tight races in Area/Extent would also tend to confirm that as well.

I'm going to be very interested in about 72 hours to see what havoc the rainfall has caused.  A lot is about to land on some of the most vulnerable ice in the Beaufort, and the Kara/Barentz is already slush.
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binntho

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Re: The 2019 melting season
« Reply #3081 on: July 02, 2019, 07:39:14 AM »
Hello, can you look at
https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2019-06-29-T00%3A00%3A00Z&z=3&v=-835137.1514222269,-920779.3466764247,-507457.1514222269,-748875.3466764247&ab=on&as=2019-06-28T00%3A00%3A00Z&ae=2019-07-01T00%3A00%3A00Z&av=3&al=true

it's part of CAA. It was the bluest fast ice I could see. The ponds must have been deep there. And a few days ago it started to be infected by some growing white thing (run animation). Guess it's not much freezing, at around 0-7deg C, and it started from shores and older cracks. Is it pond draining before it disappear maybe then?
I think your guess is correct,the spreading white is presumably caused by meltponds draining, which implies thinner ice. How thin? I've no idea.

b_lumenkraft

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Re: The 2019 melting season
« Reply #3082 on: July 02, 2019, 08:00:35 AM »
Hello, can you look at
https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2019-06-29-T00%3A00%3A00Z&z=3&v=-835137.1514222269,-920779.3466764247,-507457.1514222269,-748875.3466764247&ab=on&as=2019-06-28T00%3A00%3A00Z&ae=2019-07-01T00%3A00%3A00Z&av=3&al=true

it's part of CAA. It was the bluest fast ice I could see. The ponds must have been deep there. And a few days ago it started to be infected by some growing white thing (run animation). Guess it's not much freezing, at around 0-7deg C, and it started from shores and older cracks. Is it pond draining before it disappear maybe then?

When a melt pond forms, water would try to drain through cracks in the ice. When the water below  is cold, the water coming from above would freeze at the bottom of the ice. The melt pond is now sealed, meltwater can accumulate on top.

When the water below the ice is warm though, the sealing effecct will stop. Now the water can drain through the ice freely. I think this is what's going on here.

binntho

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Re: The 2019 melting season
« Reply #3083 on: July 02, 2019, 08:07:08 AM »
Hello, can you look at
https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2019-06-29-T00%3A00%3A00Z&z=3&v=-835137.1514222269,-920779.3466764247,-507457.1514222269,-748875.3466764247&ab=on&as=2019-06-28T00%3A00%3A00Z&ae=2019-07-01T00%3A00%3A00Z&av=3&al=true

it's part of CAA. It was the bluest fast ice I could see. The ponds must have been deep there. And a few days ago it started to be infected by some growing white thing (run animation). Guess it's not much freezing, at around 0-7deg C, and it started from shores and older cracks. Is it pond draining before it disappear maybe then?

When a melt pond forms, water would try to drain through cracks in the ice. When the water below  is cold, the water coming from above would freeze at the bottom of the ice. The melt pond is now sealed, meltwater can accumulate on top.

When the water below the ice is warm though, the sealing effecct will stop. Now the water can drain through the ice freely. I think this is what's going on here.

I'm not sure this is totally correct. The water in the meltpond will seep into cracks in the underlying ice and freeze there as has apparently been confirmed in direct observation. And this will happen even with strong bottom melt ongoing as well, i.e. this freezing is not caused by the underlying sea temperatures, but the internal temperature of the ice. But at some point the structural integrity of the ice is not strong enough, or the internal temperature is not low enough, and the cracks stay open and once the water starts flowing, I guess the cracks will widen very quickly, leading to very rapid loss of surface water.

b_lumenkraft

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Re: The 2019 melting season
« Reply #3084 on: July 02, 2019, 08:16:52 AM »
Sure, Binntho, that makes sense.

I tried to keep it simple. :)

subgeometer

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Re: The 2019 melting season
« Reply #3085 on: July 02, 2019, 08:25:13 AM »
I've included a couple of archived Bremen concentration maps (earliest I could get for July was the 23rd), and as you can see, 2012 and 2016 don't appear definitively "holier" than 2019; at least from what I can tell. (edit - though 2019 has a lot more purely open water.)
Here's the Bremen map for the 3rd July 2012.
Brilliant!  Thank you!

I think it does bear me out; I don't think either year was particularly more dispersed than we are currently; the tight races in Area/Extent would also tend to confirm that as well.

I'm going to be very interested in about 72 hours to see what havoc the rainfall has caused.  A lot is about to land on some of the most vulnerable ice in the Beaufort, and the Kara/Barentz is already slush.

today's Bremen map shows damage from the last rain band a couple of days ago, the open water connection between Beaufort and Chykchihas grown considerably(the face's nose is almost gone, lips receding)

Neven

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Re: The 2019 melting season
« Reply #3086 on: July 02, 2019, 08:26:50 AM »
The balance imo is that despite all the heat and energy, the ice pack over the Cab region is not full of holes like it was in 2016 and 2012 which may of played a factor in those years having lower minimum.

This is not something that needs to be 'balanced'. The implication is that things aren't really that bad, because look, 2012 was much worse. This is what annoys people and brings out the troll accusations. Because practically no one is saying - as of yet - that 2019 is looking much worse than 2012 in every respect. Things simply look very bad, that's all, but we don't know what the next weeks will bring.

Quote
I guess this melt season may test what is worse for the ice long term, dispersion or melt ponding?

I agree, but it's the weather that will determine this. And remember the famous quote: In the end, it will just melt away quite suddenly. It's not like there is dispersion first, and only then does it melt away quite suddenly. We have all witnessed large-scale flash melting events.

Now, I'm going to wait for the latest PIOMAS data before I really start comparing 2012 and 2019 (thickness distribution could be crucial), but here's one thing: 2012 and 2019 are on a par when it comes to compactness (and they're both lower than 2016). The level of compactness is determined by two factors: dispersion and melt ponds. If Michael is correct and 2012 has more dispersion than 2019, this means that 2019 has more melt ponding than 2012 (which I doubt, but never mind).

I happen to believe that melt ponds are worse than dispersion, because dispersion may warm up the water between floes and nibble at the sides, but melt ponds nibble at the whole floe and warm up the water below it. But I could be wrong.

Either way, the situation is bad right now. This may change. Saying (or worse, implying) that it's not all that bad, isn't 'balance', it's factually wrong.
Il faut comparer, comparer, comparer, et cultiver notre jardin

Yuha

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Re: The 2019 melting season
« Reply #3087 on: July 02, 2019, 08:36:18 AM »
I don't agree with Michael Hauber on everything but he is correct about two things.

1. There was much more dispersal in that area in 2012 than this year. Just check the Worldview.
However, this kind of dispersal is not caused by melt but by cyclonic winds. So the dispersal is not a sign of strong melt, but it does make the ice more vulnerable because it lowers the albedo.

2. This is area is an important reason why 2012 went so low. The summer 2012 wasn't exceptionally warm and sunny in the ESS sector but still the extent there ended up lower than any other year except 2007. The dispersal might have contributed to this but there was two more important factors. First, check out the melt pond fractions in Neven's latest blog post. This area had strong melt ponds already in May. Second, the GAC totally obliterated the ice here. Maybe it would have melted anyway but the GAC made sure of it.

ArcticMelt2

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Re: The 2019 melting season
« Reply #3088 on: July 02, 2019, 09:08:34 AM »
Models say that a catastrophic invasion of heat into the Chukchi Sea will begin July 6-7. How reliable are these forecasts?

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Re: The 2019 melting season
« Reply #3089 on: July 02, 2019, 09:50:38 AM »
I don't agree with Michael Hauber on everything but he is correct about two things.

1. There was much more dispersal in that area in 2012 than this year. Just check the Worldview.
However, this kind of dispersal is not caused by melt but by cyclonic winds. So the dispersal is not a sign of strong melt, but it does make the ice more vulnerable because it lowers the albedo.

I'd *really* like to know where people are getting this.  Right now it still sounds like anecdote, not fact.  I need to look at Wip's numbers.  Or someone smarter than me does.  CAPIE would set us all straight.

This space for Rent.

Rich

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Re: The 2019 melting season
« Reply #3090 on: July 02, 2019, 10:17:03 AM »
Some observations on the wind conditions in the Arctic.

There's a cyclonic wind in the ESS which is dominating the Pacific side of the Arctic.

All of the flow coming through the Strait and almost everything from McKenzie is being steered to the Siberian Islands. We see the influence from opening the CAA / CAB crack to slamming the ESS ice back into the coast.

There is a very small pocket of wind pushing ice from Banks Island toward the Alaskan coast. Minor dispersal and promoting melt.

On the other side of the Arctic both Nares and Fram are bring fed by strong winds. The ice between Svalbard and the pole is getting a 15 knot push toward Fram and a 25 knot slingshot off of Svalbard. On the NW side of Greenland, there are 15 knot winds pushing into Nares and the eastern CAA.

Strong winds coming out of the Kara, but at this point not super relevant to the end of season ice outcome.

Paul

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Re: The 2019 melting season
« Reply #3091 on: July 02, 2019, 12:56:42 PM »
The balance imo is that despite all the heat and energy, the ice pack over the Cab region is not full of holes like it was in 2016 and 2012 which may of played a factor in those years having lower minimum.

This is not something that needs to be 'balanced'. The implication is that things aren't really that bad, because look, 2012 was much worse. This is what annoys people and brings out the troll accusations. Because practically no one is saying - as of yet - that 2019 is looking much worse than 2012 in every respect. Things simply look very bad, that's all, but we don't know what the next weeks will bring.


I want to clarify that I dont think this year is not looking too bad, I think the weather conditions have given the ice quite a hard time really especially on the Pacific side of the basin and the high temperatures have played a role in very high SSTS which could have a impact in the 2nd part of the melt season. However I would say the cavet on why this melt season may not reach record lows is down to the lack of
 dispersion in the CAB because of winds largely compacting the ice and the lack of any real strong storms(I think only one deep low crossed the CAB but it only lasted a day). Of course melt ponding has been high this year so that may play a role and this is what I'm finding interesting about this year because it could tell us which is more damaging to the ice long term. Its why I also believe its not quite as simple as saying high pressure is bad for the ice and low pressure is good because we saw in 2012 and 2016 persistent low pressure can weaken the inner part of the ice pack.

My theory is persistent cyclones can slow down the melt at lower latitudes but it's making the centre more vulnable because of dispersion whereas high pressure is the opposite but as 2007 and to a lesser extent 2011 shows, too much high pressure can reduce extent quite alot.

Rich

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Re: The 2019 melting season
« Reply #3092 on: July 02, 2019, 01:23:39 PM »
The dictionary defines dispersion as "spreading things over a wide area".

I think the people who are claiming low dispersion in 2019 should provide a more precise definition of dispersion that they are working.

If we look at the following sources of dispersion in 2019, I see dispersion as high.

1) Export from CAB to Greenland Sea through Fram

2) Export from CAB to Baffin through Nares

3) Export from Laptev / CAB to Barents / FJL via coastal cyclone

4) Transport from Beaufort ice pack to Alaskan / Canadian coast via Beaufort / CAA cyclone

Are the people claiming low dispersion somehow excluding these things from your definition?

From a common definition of the word, it doesn't seem like the case for low dispersion in 2019 is solid.

Sterks

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Re: The 2019 melting season
« Reply #3093 on: July 02, 2019, 01:30:46 PM »
The dispersion used here means "dispersion of the pack in floes separating to each other". The examples we have today is Beaufort and somehow Kara. Caused by storms, usually.
Many examples you bring are called Trasport, or export, ect

Juan C. García

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Re: The 2019 melting season
« Reply #3094 on: July 02, 2019, 02:11:40 PM »
It seems unusual to me the wind coming from south Asia to the Bering Strait. I don't see the normal jet stream. Instead, a flow south to north. It is coming a lot of heat to the Arctic, with this wind pattern?

https://earth.nullschool.net/#current/wind/isobaric/700hPa/orthographic=-212.00,61.11,316
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Pagophilus

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Re: The 2019 melting season
« Reply #3095 on: July 02, 2019, 02:11:48 PM »
The dispersion used here means "dispersion of the pack in floes separating to each other". The examples we have today is Beaufort and somehow Kara. Caused by storms, usually.
Many examples you bring are called Trasport, or export, ect
A useful clarification.  Thank you.  But I see Rich's point too.
>>I assume transport can just mean ice moving from A to B without necessarily becoming more spread out (dispersed).
>>Export I assume simply means ice leaving the area under discussion. 

But pragmatically, for the Arctic as a whole, doesn't export usually effectively mean dispersion too?  Ice floes spreading apart in the Beaufort and melting because they are separating does not seem much different (to me) than ice floes exiting the Fram and (usually) spreading apart and melting.  Is it not valid to say that the CAB ice that exits the Fram has effectively spread out (dispersed) over a larger area?

I get that the nomenclature has to be carefully applied (and you have helped me with this through your reply) but I think that in essence Rich is correct to raise the other issues.  We need to consider what is happening to the ice overall in terms of its 'spreading out' if we are to get a full picture of this season or any other.   Like Rich I noticed that in arguments above in this thread, the debate centered on melt ponding versus dispersion as indicators of a minimum.  Where does export fit into all of that?

binntho

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Re: The 2019 melting season
« Reply #3096 on: July 02, 2019, 02:14:52 PM »
I would tend to agree with the anti-dispersionists (i.e. those who claim less dispersion this year than e.g. 2012 or 2016) when judging from the visuals only. But as others have pointed out, various fairly reliable metrics do not support the anti-dispersionist worldview.

It so happens that the 1st of July every year since 2006 has been fairly free of clouds in a large area of the CAB bordering the ESS and the Laptev, as can be seen in the gif. Four years stick out as being significantly more dispersed than the current, i.e. 2008, 2012, 2013 and 2016.

There is obviously some cloud cover in all of the images, in different places, but practically every year gives a relatively fair impression of itself - those that doubt this and think that extra dispersion is hidden under the clouds for a given year can go back and check, but I've done this and I didn't find anything suspicious.

Click for animation.

Sterks

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Re: The 2019 melting season
« Reply #3097 on: July 02, 2019, 02:29:54 PM »
Pagophilus, I don't want to be snipped by the owner two days in a row so I'll just say, that's the way I understand dispersion vs export as used in this forum, and Fram Export in particular does not generally have to do with dispersion (as understood in this Forum)

Rich

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Re: The 2019 melting season
« Reply #3098 on: July 02, 2019, 02:33:08 PM »
The dispersion used here means "dispersion of the pack in floes separating to each other". The examples we have today is Beaufort and somehow Kara. Caused by storms, usually.
Many examples you bring are called Trasport, or export, ect

The tricky thing here is that export meets the definition of dispersion. It also involves floes separating from each other.

Adding the qualifier "storm related" is helpful, but a lot of the export via Fram has been storm wind aided as it is currently.

Anyway...this is helpful. I'll assume people are talking about export free dispersion when they mention dispersion going forward.

ajouis

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Re: The 2019 melting season
« Reply #3099 on: July 02, 2019, 02:36:55 PM »
I don t know about the dispersion data difference between 2019 and 2012, although i have seen high dispersal in beaufort and some parts of ess, but 2019 has much more open water than 2012. This might be explained by higher compaction, but is definitely not good for the ice. The ice will start to disperse anyways later on, and this increases the killing zones and the speed of the edge retreat. I am not an expert on currents, but maybe instead of being a year with strong dispersion, and while having respectable meltponding momentum, the added heat could mean much higher bottom melting per square meter.