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b_lumenkraft

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Re: The 2019 melting season
« Reply #1600 on: June 08, 2019, 07:27:27 AM »
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Glen Koehler

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Re: The 2019 melting season
« Reply #1601 on: June 08, 2019, 07:28:45 AM »
1. RE:  Thicker snow cover on floes.
But with NH hemisphere snow cover low this year, and with snow cover north of Greenland going out earlier than "normal" (not sure what that word means anymore), then why would there be thicker snow cover this year to interfere with melt pond detection?

2.  If snow cover is interfering with melt pond detection, it seems like that situation should turn around quickly with the heat forecast for coming week.

3.  What's the typical date by which information on melt ponds is considered measured and applicable as a predictor for the remainder of the melt season?


Milwen

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Re: The 2019 melting season
« Reply #1602 on: June 08, 2019, 08:40:39 AM »
It seems like the oldest ice in arctic (4+ years old) strip above Nunavut region and in Lincoln Sea will have rough times in next 4 days. Image below from earth.nullschool map shows surface temp in June 12 near 3.5°C.





slow wing

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Re: The 2019 melting season
« Reply #1603 on: June 08, 2019, 09:34:27 AM »
Imo it's premature to be surprised about the small fraction of ice surface showing melt ponds.

Attached is a gif of SMOS microwave images for each year from 2010 through 2019.

Specifically, the images are yyyy0607_hvnorth_rfi_l1c.png, where yyyy is the year, obtained from https://seaice.uni-bremen.de/data/smos/png/.

These images are sensitive to melt ponds.
IGNORE THE COLOR LEGEND'S NUMERICAL SCALE & LABEL (the color order progression should be valid though) - DURING THE MELT SEASON THESE ARE NOT LEGITIMATE THICKNESS MEASUREMENTS. Instead, my understanding is that any color other than beige indicates ice that is:
a) thin, ~<50 cm; &/or
b) has concentration well below 100%; &/or
c) has surface liquid water.
In particular, colours other than beige in the ice pack interior are likely to indicate the presence of surface water.

& it is seen that only 4 of the 10 years have extensive melt ponding in the Arctic Basin on 7 June: 2012, 15, 16, and 18.

All of 2010, 11, 13, 14, 17, and now 2019, don't have extensive melt ponding by 7 June.

So the comparisons above with 2012 are not particularly surprising, given that 2012 is one of the 4 years in the data record that has extensive melt ponding on 7 June, while 5 of the 9 previous years on record are similar to 2019 in not displaying extensive melt ponds by 7 June.


P.S. Given the weather forecast, I expect SMOS to show extensive melt ponding, especially on the Russian side, within the next few days.
« Last Edit: June 08, 2019, 10:35:57 AM by slow wing »

binntho

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Re: The 2019 melting season
« Reply #1604 on: June 08, 2019, 10:12:55 AM »
Indeed, and as said before, I think it may have to do with melt onset (which starts earlier under cloudy, moist conditions). Here's that paper I referred to, called Melt onset over Arctic sea ice controlled by atmospheric moisture transport: 2016 Mortin et al. I still haven't looked at it properly, to see whether 2010 and 2012 were extra early.

But here's what it's about:

Quote
....When melt occurs early, an anomalously opaque atmosphere with positive LWD anomalies preconditions the surface for weeks preceding melt. In contrast, when melt begins late, clearer than usual conditions are evident prior to melt. ...

Sorry, for the slightly off-topic, but given that May was so sunny and there was thus less atmospheric moisture transport, this could possibly explain why 2019 is lagging when it comes to melt ponding. Because the ice wasn't pre-preconditioned as much as in other years.

I think this is the best explanation yet as to why melt ponding has not started yet - it's been too sunny too early.
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peterlvmeng

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Re: The 2019 melting season
« Reply #1605 on: June 08, 2019, 11:24:33 AM »
Here is almost all of the near real-time evidence we have for melting momentum. I could also post SMOS maps, or even Uni Bremen SIC maps, but that's just too much work.

That is really a good comparison. Let us think more about the essence of melting pond. Why we study the melting pond? Lower albedo, more energy insolation, right? Now think about if the arctic sea ice do not have much melting pond, but sea ice retreat pretty earlier, more open water exist in Beaufort sea, or pacific side. You think the whole arctic receive more solar energy or not? Dark ocean in satellite image shows much lower albedo than melting pond, right? You guys focus to much attention on melting pond because you can exactly see the melting process on the ice but ignoring the open water insolation effect. The melting pond starts to become so pronounced in 2012 was in June 7th, however, the heat wave will prevail the arctic since June 10th through google earth prediction this year. The melting pond will not delay too much this year. The weather condition is also favorable for ice transpotation to Atlantic side next week. It is still the worst year for arctic up to now.
« Last Edit: June 08, 2019, 11:32:09 AM by peterlvmeng »

Neven

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Re: The 2019 melting season
« Reply #1606 on: June 08, 2019, 12:27:37 PM »
peterlvmeng, melt ponds are crucial for melting momentum (where the ice continues to melt in July and August, almost regardless of weather conditions). That's because the water is on the ice, whereas open water is just at the edges, and the really warm waters are often further removed from the ice pack.

But I agree that there is still plenty of time for this year to develop melting momentum, and that it compensates the lack so far in other ways (thickness distribution, open water, snow cover, transport).

If enough melting momentum does develop, this year could go record low. There's always a moment during any given melting season where one can say: This year won't break records. There are no signs of this, right now, except perhaps for that slight lack of melting momentum. But this particular aspect is hard to assess, and it's too early to tell anyway.
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BenB

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Re: The 2019 melting season
« Reply #1607 on: June 08, 2019, 12:54:09 PM »
A couple of points about the lack of melt ponding and dry vs humid air.

Although the ice is quite fragmented in places, the individual ice floes are still mainly hundreds of metres or even tens of kilometres across. More than big enough for melt ponds, and more than big enough for the melt ponds to be big enough to be visible on one of the products available to us. 

The latent heat of vaporisation of water is roughly 7 times higher than the latent heat of fusion (melting). This means that 1 g of water condensing releases enough energy to the surroundings to melt 7 g of ice (assuming the ice temperature was close to freezing point). When warm humid air enters the Arctic, it cools, and some of the water vapour condenses, releasing energy. This can start surface melting and melt ponding. In past years we've frequently seen this happen in practice - a warm, cloudy weather system moves through part of the CAB, and when it leaves and you can see the area on Modis again, there is lots of surface melt/melt ponding. Obviously if the weather front brings rain as well, this will also contribute to melting. This effect has also sometimes been visible on the buoys.

b_lumenkraft

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Re: The 2019 melting season
« Reply #1608 on: June 08, 2019, 01:25:24 PM »
Khatanga Gulf doing the Lena Delta thing.

(Click to play)

FishOutofWater

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Re: The 2019 melting season
« Reply #1609 on: June 08, 2019, 02:59:55 PM »
Here's my take on why it has taken a little more time this year for melt ponds to form.

I think that there is one negative feedback that's helped the sea ice out a bit. The expanded area of open water in the fall in the Barents and Kara seas in this decade compared to the naughts has led to increased fall and winter snowfall amounts in northern Siberia. It takes a large amount of energy to melt that snow in spring.

This May we saw a very rapid retreat of Siberian snow when the heat turned on but the southerly winds over the Arctic were snow cooled. The snow cooling also extracted water vapor from the southerly winds. In springtime, the Arctic region that heats up the fastest is Siberia, but a heavy snow pack holds back the heating from reaching the Arctic sea ice. I think that's what we have seen this year. Perhaps this effect will keep this year's ice extent from declining below the 2012 minimum.

Sambuccu

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Re: The 2019 melting season
« Reply #1610 on: June 08, 2019, 03:13:37 PM »
Could dry air and sustained wind in anticyclonic but dynamic situations lead to more ice sublimation and less ordinary melt ?
I know it in mediterranean mountain. Snow can desappear without even giving water in those situations.

magnamentis

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Re: The 2019 melting season
« Reply #1611 on: June 08, 2019, 03:30:40 PM »
Wow the pseudo-science cavalry join together.

pseudo would mean that one is claiming to be a scientist but  isn't. if that's not the case it's only about providing impressions and opinions based on experience and logical thinking sometimes right sometimes wrong, exactly like the real scientists are sometimes spot on and sometimes far off the marks.

however that is and in case you disagree, no need to be arrogant because often those who are no experts in one field are close to be experts in hundreds of fields and have a bigger picture of things.

and then again others are experts in other fields where you are not, perhaps they're even scientist but in other fields.

in short, keep this kind of thoughts for yourself, at least you have just proven that you are no expert in many fields like education, communication, style, philosophy and many more.

so long

binntho

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Re: The 2019 melting season
« Reply #1612 on: June 08, 2019, 03:42:04 PM »
Wow the pseudo-science cavalry join together.

pseudo would mean that one is claiming to be a scientist but  isn't.

No it doesn't. Sterks' appellation may be untrue, the "cavalry" in question does not dabble in pseudo science - but too frequently the seem to be haring after something that is not quite science either.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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FishOutofWater

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Re: The 2019 melting season
« Reply #1613 on: June 08, 2019, 03:55:59 PM »
2012 was exceptional so when we talk about general rules like high pressure and clear skies, that's not wrong, but it's not enough to make this year beat 2012 in terns of warmth and melt ponds. This year Ellesmere island region snow and ice loss is ahead of 2012. However, this year is way behind 2012 in warming up on the Siberian side of the Arctic.

Last winter and early spring was exceptionally warm in Alaska. Thus, it's not surprising that the Beaufort sea has opened up early and ice is melting quickly there. Likewise it was very warm in the Bering sea region.

It's easy for us to forget how extraordinarily hot it was in western Siberia in 2012. Fortunately, this year has not been so warm in Siberia. See the figures in the paper linked below.
https://www.biogeosciences.net/10/5349/2013/bg-10-5349-2013.pdf

BenB

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Re: The 2019 melting season
« Reply #1614 on: June 08, 2019, 04:38:40 PM »
This page provides quite a lot of good information about snow melt processes, including sublimation:

http://portal.chmi.cz/files/portal/docs/poboc/CB/snowmelt/print.htm

With respect to the process I was describing, it has this to say (my bold):

When vapor pressure decreases with height in the atmosphere, moisture from the snow will be diffused to the atmosphere above. In this situation, moisture sublimates from the snow, latent heat is lost from the snow, and the snow stays cold, even if the air temperatures are rather warm.

When vapor pressure increases with height in the atmosphere, moisture from the atmosphere above will be deposited to the snow's surface. In this situation, latent heat is gained by the snow, and the snow surface will warm. This warming may start the melting process within the snowpack. To achieve melting in this manner requires winds strong enough to induce turbulent transfer, so that warmth and higher humidity from above continually come into contact with the snow surface.

FishOutofWater

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Re: The 2019 melting season
« Reply #1615 on: June 08, 2019, 04:49:09 PM »
Ben, that's a good paper. In 2012 Worldview shows storms in the Siberian seas pulling warm, humid air off of Eurasia. This year there have been storms in that region but the snow took longer to melt out, probably because it was deeper to start with. Siberian snow extracts heat and humidity from air masses that are blowing towards the Arctic ocean.

Blue shows up in 2012 earliest of all years in the Siberian seas. The snow in eastern Siberia made a record early retreat in 2012. That early exposure of east Siberian ground allowed for heat and humidity to build up over the landmass which was subsequently blown over the sea ice causing extensive early melt ponds.

BenB

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Re: The 2019 melting season
« Reply #1616 on: June 08, 2019, 05:21:51 PM »
Yes, Fish, snow cover definitely seems important, and no doubt for the reason you say. Most of the snow cover has melted now, a bit earlier than in many recent years (if I remember correctly), so it will be interesting to see what happens next.

peterlvmeng

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Re: The 2019 melting season
« Reply #1617 on: June 08, 2019, 05:45:01 PM »
peterlvmeng, melt ponds are crucial for melting momentum (where the ice continues to melt in July and August, almost regardless of weather conditions). That's because the water is on the ice, whereas open water is just at the edges, and the really warm waters are often further removed from the ice pack.

But I agree that there is still plenty of time for this year to develop melting momentum, and that it compensates the lack so far in other ways (thickness distribution, open water, snow cover, transport).

If enough melting momentum does develop, this year could go record low. There's always a moment during any given melting season where one can say: This year won't break records. There are no signs of this, right now, except perhaps for that slight lack of melting momentum. But this particular aspect is hard to assess, and it's too early to tell anyway.

Neven, it is really true that melt pond plays a role in momentum build up. My major is fluid dynamics focusing on multiphase flow. I tend to regrad the melt pond forming is the starting point of maasive melting no matter through satellite image or sea ice extent curve. It is quite similar to the process of water boiling. The bubble will generate at lower superheat degree if the kettle wall has more nucleus. vaporization,condensation,melting all these phase change process will be accelerated if proper nucleus exist. I do not detailed study the mechanism melt pond formation though some research shows the cloudy and moisture condition acts as a catalyst. I think the moisture (aresol) is what I have called the nucleus to fasten the formation of melt ponds. The melt pond form usually along the coastal area first then gradually intruding the heart of arctic basin. It is quite similar to the boiling process that bubble form on the kettle wall first then the whole water is highly churned with bubble when the saturation temperature arrives. My point is that although we do not see early melt pond but the air average temperature is quite high in May also likely in June, once the melt ponds begin to form, the high temperature will quickly spread  the melt pond to the heart of arctic. My prediction is that the melt pond will aggressively spread over the entire arctic sea within 7 days as massive heat wave intruding. In the following days, I am eager to see the validation of my hypothesis.

Aluminium

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Re: The 2019 melting season
« Reply #1618 on: June 08, 2019, 06:15:28 PM »
2019 and 2018. 850 hPa.

Shared Humanity

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Re: The 2019 melting season
« Reply #1619 on: June 08, 2019, 06:16:36 PM »
Since melt ponding is dominating, appropriately I might add, this conversation, I thought I would link to research that explains the creation of and persistence of melt ponds, even on thin, briny FYI.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JC011994

FishOutofWater

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Re: The 2019 melting season
« Reply #1620 on: June 08, 2019, 06:53:05 PM »
The key to the existence of melt ponds is that fresh water from melted snow enters the pores and fractures and refreezes. The freezing point of fresh water is higher than the freezing point of salty first year ice or the basal ice/salt water mixture.

Quote below from the summary of the linked article:

Plain Language Summary

When meltwater pools atop Arctic sea ice it greatly increases how much sunlight the ice absorbs and how fast it melts. The formation of so‐called melt ponds on the sea ice is a major contributor to summer ice melt, but the fact that the ponds form at all is surprising. The sea ice is very porous and water should trickle right through it. We found the mechanism that allows ponds to form. When freshwater, from melting snow, percolates into the salty, cold ice interior, it re‐freezes, plugging the pores in the sea ice and making it so that ponds cannot drain. This very important process is not captured by current global climate models, and we suggest that working to include it in future models will improve the predictions the models produce of future sea ice.

Alphabet Hotel

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Re: The 2019 melting season
« Reply #1621 on: June 08, 2019, 07:15:55 PM »
This latest forecast seems a bit ... inconclusive?

kassy

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Re: The 2019 melting season
« Reply #1622 on: June 08, 2019, 08:04:08 PM »
It is the right time of the year for that.  ;)
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Re: The 2019 melting season
« Reply #1623 on: June 08, 2019, 09:27:12 PM »
Could dry air and sustained wind in anticyclonic but dynamic situations lead to more ice sublimation and less ordinary melt ?
I know it in mediterranean mountain. Snow can desappear without even giving water in those situations.

I was thinking that, so I dug into it a little and came to the conclusion that although there may be some sublimation going on, it's likely not shockingly huge. It's a big effect on south-facing mountainsides with low air pressure and very dry air, but not so much at sea-level with any humidity at all.

Neven

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Re: The 2019 melting season
« Reply #1624 on: June 08, 2019, 09:40:42 PM »
DMI sea surface temperature anomalies around this date (2012 is for June 15th). 2019 very similar to 2016, except for North Atlantic.
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Glen Koehler

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Re: The 2019 melting season
« Reply #1625 on: June 08, 2019, 09:50:11 PM »
Good explanation of the Arctic Dipole and its interaction with Arctic Sea Ice
https://en.wikipedia.org/wiki/Arctic_dipole_anomaly

Jeff Masters - Weather Underground - the early June Arctic forecast and prospects for summer
https://www.wunderground.com/cat6/Strong-Arctic-High-Pressure-System-Bringing-Significant-Melting-Sea-Ice

subgeometer

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Re: The 2019 melting season
« Reply #1626 on: June 09, 2019, 03:38:52 AM »
Ben, that's a good paper. In 2012 Worldview shows storms in the Siberian seas pulling warm, humid air off of Eurasia. This year there have been storms in that region but the snow took longer to melt out, probably because it was deeper to start with. Siberian snow extracts heat and humidity from air masses that are blowing towards the Arctic ocean.

Blue shows up in 2012 earliest of all years in the Siberian seas. The snow in eastern Siberia made a record early retreat in 2012. That early exposure of east Siberian ground allowed for heat and humidity to build up over the landmass which was subsequently blown over the sea ice causing extensive early melt ponds.

Enhanced evaporation in the Barents etc and snowfall in Siberia also implies increased emission of energy to space as the water vapour condenses? Something of a negative feedback

Fresh water percolating into porous ice and refreezing sounds like a very effective way of warming the interior of the ice,  preconditioning it for melt

One interesting takeaway from the Jeff Masters Wunderground story is that the 2 years with the warmest Mays over the arctic basin, 2010 and 2019, are both late with melt pond formation.
« Last Edit: June 09, 2019, 03:48:43 AM by subgeometer »

b_lumenkraft

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Re: The 2019 melting season
« Reply #1627 on: June 09, 2019, 07:37:50 AM »
Re: Freshwater refreezing on the bottom of the ice and sealing it.

Here it didn't work. This is the west side of the Lena Delta. You can see freshwater from land spillover, flood the ice, and then drain through the ice.

(Click to play)

binntho

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Re: The 2019 melting season
« Reply #1628 on: June 09, 2019, 07:43:27 AM »
Re: Freshwater refreezing on the bottom of the ice and sealing it.

Here it didn't work. This is the west side of the Lena Delta. You can see freshwater from land spillover, flood the ice, and then drain through the ice.

This is of course not the same as when meltwater forms on the surface of the ice and drains towards the bottom.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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b_lumenkraft

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Re: The 2019 melting season
« Reply #1629 on: June 09, 2019, 07:49:06 AM »
Well, for the rest of the Lena Delta this effect seems to be working (for now).

The drained area is marked red.

subgeometer

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Re: The 2019 melting season
« Reply #1630 on: June 09, 2019, 08:24:38 AM »
There is quite a bit of darkening spreading north on the fast ice in the Laptev Sea today on Worldview, eg around the northern side of the Lena delta(where a diminishing cover of land snow is still hanging on - but not for much longer. Animations in a few days are going to show some dramatic change in the pack's appearance, at the least

meddoc

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Re: The 2019 melting season
« Reply #1631 on: June 09, 2019, 08:33:20 AM »
On artcic.io seems like the whole Pack is being pushed through Nares & Svalbard & also into the hot Laptev Waters.

subgeometer

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Re: The 2019 melting season
« Reply #1632 on: June 09, 2019, 08:36:19 AM »
Re: Freshwater refreezing on the bottom of the ice and sealing it.

Here it didn't work. This is the west side of the Lena Delta. You can see freshwater from land spillover, flood the ice, and then drain through the ice.

(Click to play)

The Lena's flow at this time year is greater than the the Amazon average, I'm not sure what percentage of that has been flowing out over the ice, but its a lot. I wouldn't consider it typical of melt ponds

b_lumenkraft

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Re: The 2019 melting season
« Reply #1633 on: June 09, 2019, 08:59:15 AM »
I'm not saying the water there is a melt pond.

What i'm trying to say is that the freshwater coming from land might cause the same effect.

The physics as described is so that (fresh) water would penetrate the ice, refreeze on the bottom and therefore sealing it, causing the flow of water through the ice to stop.

If it's a melt pond or water coming from land, it could be the same physics at work here, no?

« Last Edit: June 09, 2019, 09:07:19 AM by b_lumenkraft »

b_lumenkraft

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Re: The 2019 melting season
« Reply #1634 on: June 09, 2019, 09:06:43 AM »
There is quite a bit of darkening spreading north on the fast ice in the Laptev Sea

This is interesting! In M8 band it was visible on 06.06.

https://forum.arctic-sea-ice.net/index.php/topic,2591.msg204032.html#msg204032

Aluminium

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Re: The 2019 melting season
« Reply #1635 on: June 09, 2019, 09:18:41 AM »
June 4-8.

Rich

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Re: The 2019 melting season
« Reply #1636 on: June 09, 2019, 09:44:35 AM »
Thanks again for the great gif Aluminum. I think the possibility of sailing from the Atlantic to the Pacific by end of June is starting to emerge.

Perhaps fodder for another poll?

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Re: The 2019 melting season
« Reply #1637 on: June 09, 2019, 09:44:40 AM »
On Laptev Sea 2012 is still leading 2019. Just an observation, not making too much about it
Amateur observations of Sea Ice since 2003.

binntho

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Re: The 2019 melting season
« Reply #1638 on: June 09, 2019, 10:26:56 AM »
I'm not saying the water there is a melt pond.

What i'm trying to say is that the freshwater coming from land might cause the same effect.

The physics as described is so that (fresh) water would penetrate the ice, refreeze on the bottom and therefore sealing it, causing the flow of water through the ice to stop.

If it's a melt pond or water coming from land, it could be the same physics at work here, no?
Of course the same physics are at work - but water from a river in spate is going to be muddy and warmer than just-thawed ice. Having said that, I'm sure that it is exactly the same that happens, the water freezes at the bottom and seals itself from going through the ice. But that is only a temporary solution, water in meltponds as well as river water will eventually drain through if melt continues.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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gerontocrat

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Re: The 2019 melting season
« Reply #1639 on: June 09, 2019, 11:28:27 AM »
Re: Freshwater refreezing on the bottom of the ice and sealing it.

Here it didn't work. This is the west side of the Lena Delta. You can see freshwater from land spillover, flood the ice, and then drain through the ice.

The Lena's flow at this time year is greater than the the Amazon average, I'm not sure what percentage of that has been flowing out over the ice, but its a lot. I wouldn't consider it typical of melt ponds

Attached is the river flow of Lena graph (by percentages and m3 / sec
« Last Edit: June 09, 2019, 11:34:34 AM by gerontocrat »
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Re: The 2019 melting season
« Reply #1640 on: June 09, 2019, 12:24:52 PM »
Some fast ice is beginning to pulled away in the ESS. (First attachment,  band I1 with I3 overlay.
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=18&ts=1&st=0&et=0&speed=120&motion=loop&map=1&lat=0&opacity%5B0%5D=1&opacity%5B1%5D=0.5&hidden%5B0%5D=0&hidden%5B1%5D=0&pause=20190609043123&slider=-1&hide_controls=0&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i01&p%5B1%5D=band_i03&x=12211.4375&y=18844.78125


Second attachment is the EURO ensemble 5 day average sea level pressure. It screams slow extent loss.  Winds have reversed int the Chukchi already, and an amazing ice edge is visible inch thr RAMMB slider.  We should also see ice getting dispersed in the Beaufort for the time being.  The one constant is the push towards the Atlantic.  The ESS and Laptev will see persistent southerlies, and likely the most impressive extent declines.
  This isn't to say melting will halt, in fact, is should transport ice to areas it could melt quicker.  It'll be interesting to watch the floes reaction in the Chukchi in particular.


« Last Edit: June 09, 2019, 12:49:49 PM by JayW »
"To defy the laws of tradition, is a crusade only of the brave" - Les Claypool

Sterks

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Re: The 2019 melting season
« Reply #1641 on: June 09, 2019, 02:00:57 PM »
Some fast ice is beginning to pulled away in the ESS. (First attachment,  band I1 with I3 overlay.
http://rammb-slider.cira.colostate.edu/?sat=jpss&z=4&im=18&ts=1&st=0&et=0&speed=120&motion=loop&map=1&lat=0&opacity%5B0%5D=1&opacity%5B1%5D=0.5&hidden%5B0%5D=0&hidden%5B1%5D=0&pause=20190609043123&slider=-1&hide_controls=0&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_i01&p%5B1%5D=band_i03&x=12211.4375&y=18844.78125


Second attachment is the EURO ensemble 5 day average sea level pressure. It screams slow extent loss.  Winds have reversed int the Chukchi already, and an amazing ice edge is visible inch thr RAMMB slider.  We should also see ice getting dispersed in the Beaufort for the time being.  The one constant is the push towards the Atlantic.  The ESS and Laptev will see persistent southerlies, and likely the most impressive extent declines.
  This isn't to say melting will halt, in fact, is should transport ice to areas it could melt quicker.  It'll be interesting to watch the floes reaction in the Chukchi in particular.
I guess this illustrates a cold low over Beaufort and a warm low over Laptev (edit: warm front)
We should expect now some acceleration in area decline, compactness down. Beaufort is still cold but that low scattering the floes and stirring the preheated waters is slow bottom-melt slaughter we have seen other years.
« Last Edit: June 09, 2019, 02:08:18 PM by Sterks »

JayW

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Re: The 2019 melting season
« Reply #1642 on: June 09, 2019, 02:44:18 PM »

I guess this illustrates a cold low over Beaufort and a warm low over Laptev (edit: warm front)
We should expect now some acceleration in area decline, compactness down. Beaufort is still cold but that low scattering the floes and stirring the preheated waters is slow bottom-melt slaughter we have seen other years.

I think there's still question as to how cold that Beaufort low will be.  Looking at 2m temps on the ecmwf, it appears the relatively long lived cyclone becomes fairly occluded, mixing out much of the cold surface air.

https://weather.us/model-charts/euro/north-pole-zoom1/temperature/20190614-2100z.html
This is roughly a 6 day loop, temp in celcius.

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Sterks

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Re: The 2019 melting season
« Reply #1643 on: June 09, 2019, 02:45:06 PM »
The Albedo Warming Potential daily anomaly of Tealight's been taking a dive, to me looks ice pack is taking longer to shift to darker colors.
https://cryospherecomputing.tk/NRTawp.html

Today Worldview shows big changes in ESS and Laptev, perhaps tomorrow we see a change in tendency of this indicator.

Sterks

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Re: The 2019 melting season
« Reply #1644 on: June 09, 2019, 02:58:39 PM »

I think there's still question as to how cold that Beaufort low will be.  Looking at 2m temps on the ecmwf, it appears the relatively long lived cyclone becomes fairly occluded, mixing out much of the cold surface air.

https://weather.us/model-charts/euro/north-pole-zoom1/temperature/20190614-2100z.html
This is roughly a 6 day loop, temp in celcius.
A site showing ECMWF surface temp of almost the entire basin wow. THX
Yes at least it shows it will sustain negative temps for a while, probably dumping an inch or two fresh snow.
The Eurasia side otoh is going to start breaking apart with that warmth.

Aluminium

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Re: The 2019 melting season
« Reply #1645 on: June 09, 2019, 04:38:28 PM »
The Beaufort sea is going to the stratosphere.

magnamentis

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Re: The 2019 melting season
« Reply #1646 on: June 09, 2019, 06:58:26 PM »
The fast ice at Barrow doesn't appear as resilent as in 2016.

it will be gone very soon, one morning we wake up and it will be no more, i predict within days, rather than weeks.

my guess: 3-6 days from now but that's a guess based on the images of the webcam, one can't see the exact thickness.

that's almost 3 weeks, so i was of by quite some margin. i post this because forecasts and predictions should more often be verified after a while to get a feel and improve quality.

my prediction then was 3-6 days and now it's 16 days later and it can even take a few more.

 8)

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Re: The 2019 melting season
« Reply #1647 on: June 09, 2019, 09:48:43 PM »
Always seemed to me Lows have a dramatic effect on the ice, usually causing a lot of extent loss a week after it hits.  I'm sure the high's are just as bad.  Yes, they've not created melt ponds, but for the last three months have been warming more open ocean (ave. 800-1200 million km than 2012) than otherwise which I'd bet has a far longer term effect than just this year's numbers.  Lows with extensive rain might also be--apart from raw export--the only thing that can drop us to a blue ocean anytime soon. I'm worried about rain bombs hitting Greenland and causing an 80-fold increase in ice flow.
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iceman

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Re: The 2019 melting season
« Reply #1648 on: June 09, 2019, 10:14:54 PM »
The Albedo Warming Potential daily anomaly of Tealight's been taking a dive ...

That could help a lot at this time of year, yet the distribution is concerning. Much of the lower AWP anomaly area is getting blown farther toward (or into) the Barentsz.

Pavel

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Re: The 2019 melting season
« Reply #1649 on: June 09, 2019, 10:48:54 PM »
The Beaufort sea should be the killing zone for MYI. I'm confident we'll see the MYI floating on +5..+8C water later this season