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philopek

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Re: The 2019 melting season
« Reply #4950 on: July 30, 2019, 02:29:51 AM »
Can anyone explain to me the mechanism that can heat up an entire ocean by 4°C in just one day? Look at the Laptev sea, and how it warmed up in just one day. How is this possible? 4°C is a lot of heat. Where did that heat come from? Methane burp and mixing?

https://earth.nullschool.net/#current/ocean/surface/currents/overlay=sea_surface_temp_anomaly/orthographic=-28.51,97.19,1829/loc=133.558,75.075

This can happen i.e. if formerly agitated waters become calm so that the surface layer warms up.

This is most probably not the case there, hence what remains are warm winds that interact with the surface. This can especially happen when winds are warm and blow offshore so that build-up of waves is limited inside a certain range.

Also possible would be a measurement fluke due to clouds, humidity or other layers that impact measurements.

I'm sure others have more and perhaps much better ideas, just my 2 cents on first thought.

UCMiami

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Re: The 2019 melting season
« Reply #4951 on: July 30, 2019, 02:40:57 AM »
Freegrass - SSTA can always be a little misleading as you need to know what the baseline is. If you look at SST the temperature has changed by maybe 0.1C over the last five days except there appears to be a few single spots in the Laptev that record 2.9C yesterday and 0.2C the day before. I suspect those spots are data errors.

As for the SSTA - I suspect there is a data blip in the baseline for the 28th causing the sudden blip for the whole sea. When it looks crazy, it probably is crazy!  8)

Edit: Just checked a bunch of other spots in the Laptev and seeing 7/28 temps ranging from 1.3C - 2.9C so according to Nullschool there has been a sudden increase but by only max 2.7C - still wonder if this is correct but still not the wild swing in SSTA they show.

Edit2: There was also two days of solar isolation around there for the first time in a while which might result in a short spike in water surface temperature? Still a little extreme.
« Last Edit: July 30, 2019, 02:50:35 AM by UCMiami »

Frivolousz21

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Re: The 2019 melting season
« Reply #4952 on: July 30, 2019, 02:56:05 AM »
I don't think 2019 will beat 2012 in extent and area.  But it will be close.

The CAA is still going pretty solid and the Atlantic side is definitely not going to be crushed like 2012.

Kind of depends on that -NAO. Even when the AO has relaxed, the NAO ridging has refused to relent. Much the same case now. Going to be really tough to get volume losses to slow down for more than a few days with that thing hanging around.

Kind of wondering if we don't end up with a 2016-esque minimum, where we end up with a lot of low concentration ice and record low volume.

I would place odds favoring that. With the negative NAO you would think the CAA would collapse eventually
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Freegrass

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Re: The 2019 melting season
« Reply #4953 on: July 30, 2019, 03:03:14 AM »
Still a little extreme.
Yes, it sure is weird. I also checked SST, and they show an increase all over the place. 4°C may be some exaggeration from me, but the temperature went from -1.5°C to above freezing in most places, and the winds are blowing the ice straight into all that hot water. If you look at the winds in the coming days, it looks like a giant hand is pushing the entire pack away from Greenland, straight into hot water...

https://earth.nullschool.net/#2019/07/31/1200Z/wind/isobaric/1000hPa/orthographic=-44.09,94.09,1829/loc=-45.617,84.295
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subgeometer

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Re: The 2019 melting season
« Reply #4954 on: July 30, 2019, 04:37:30 AM »
Does anybody know how common this wave action is coming out of the North end of the Nares?
Windy screenshot for Wednesday two days out.

Windy has it's plusses and minuses.

You have stumbled upon one if it's flaws. The image you are sharing is generated using the "Waves* function. Windy has a flaw in that it sometimes produces areas that look like open water which are in fact covered in ice.

I noticed this a few weeks ago when the software produced an image of the NW Passage being open. If you zoom out to a CAA wide view, you can see the issue. Much more open water on Windy compared to other sources.

It's maybe not so simple as an out and out error in drawing the ice edge,

Windys model seems to be attempting to project how far beyond the ice edge wave action propagates - eg the ice covered areas showing wave action change a bit with changes in wind direction, and its generally in areas where the ice is thin and dispersed. Nares strait and the edges of the Lincoln sea have some open water and ice is definitely mobile and somewhat dispersed (pouring like sand through the hourglass) and wind is blowing up Nares Strait. I'm not sure how accurate the projections are, or if they are verified through satellite or other observations somehow, hopefully that's documented somewhere.

The ice is too spread out in the western Beaufort and adjacent CAB to completey resist or dampen wave action

subgeometer

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Re: The 2019 melting season
« Reply #4955 on: July 30, 2019, 05:04:49 AM »
SSTs are a lot easier to determine when there's no clouds to confuse or obscure the instrument? (They also rise quickly if its June or July) The DMI figures seem to often jump after a couple of days of clear weather in a region. Or drop as well - Chukchi sea SSTs are a couple of degrees below their peak a few weeks ago. In the Bering Sea Norton Sound is down to 16C from 18 in June and 20 in early July, despite weather remaining mostly warm - mixing with water from deeper and further offshore must be going on. In the Chukchi sea currents push it into the ice edge.

The Laptev Bite area has remained fairly steady at 4-8C as it melted out the ice around.

The tongue of open water north of Svalbard has gone up to 4C and is again a death trap for any ice that wanders nto it. How much effect the salty Atlantic water is having underneath the ice is something we may see revealed as August proceeds, and whether all the ice pushed into the area over the past 6 months have turned back the Atlantification trend significantly


bbr2314

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Re: The 2019 melting season
« Reply #4956 on: July 30, 2019, 05:15:25 AM »
Latest Bremen. Oof.



I don't think 2016 is a good analog because the multi-year ESS ice that year remained relatively intact, and allowed a slushiness to the NW edge of the pack that greatly increased area + extent.

This year, the MYI is going to melt out completely (most of it already has) and the FYI is not going to hold against insolation, wave action, and SSTs. We are going to have a rump pack a la 2012, if not smaller, possibly substantially so.

To my eyes the latest Bremen also shows that the remaining ice in Laptev is now failing (and EOSDIS confirms this). The ATL front is finally giving way. The only reason it hasn't til now is that the ice has been continually exported towards the ATL. A volume crusher, but this was not readily apparent in area / extent #s until mid and late July.

subgeometer

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Re: The 2019 melting season
« Reply #4957 on: July 30, 2019, 05:22:08 AM »
There's a really clear view of the ice on Worldview for yesterday(29 July), with some spectacular images of melt

Swirls of goodbye waves speckled with confetti-like small floes must present quite a challenge for the microwave instruments and their operators/programmers.

This region of the ESS - about 40000km2 just north of Wrangel Island is now mostly open water as far as NOAA and Bremen are concerned, I've attached their current extent or concentration map with the area marked.

The other Worldview image shows the ice to the west of the northernmost part of the Laptev bite, which is in a bit better condition/will melt out slightly later, and still counts for extent.

There's a band of thinning ice from here all the way to the head of the bite north west  of FJI which seems to reflect the salinity map Uniquorn posted a few days ago. Anyway I think all the ice south of this band will soon start becoming isolated from the main pack.

petm

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Re: The 2019 melting season
« Reply #4958 on: July 30, 2019, 05:28:51 AM »
Latest Bremen. Oof.

Normally I'm eager to see the destruction, but honestly this is getting scary.

Edit: Attached a gif of the last week of melt, July 23-29.

Left: 3-day lagging median. Right: Originals.

Click to animate.

PS. For a comparison to 2012, see:
https://forum.arctic-sea-ice.net/index.php/topic,2792.msg217403.html#msg217403 .
« Last Edit: July 30, 2019, 05:41:26 AM by petm »

subgeometer

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Re: The 2019 melting season
« Reply #4959 on: July 30, 2019, 05:40:06 AM »
A couple more Worldview images.

Southerlies over the past 2 days have widened the gap off NE Greenland to an alarming degree, and teased apart the pack a bit to its north, I've attached a picture of it yesterday

The other image shows the region between the Laptev Bite (top left) and FJI, and its bite (bottom right)with a band of thinning ice extending between them. Atlantification. The ice piled up against Severnaya Zemlya to ice south of the band will become isolated with the remnants in the Kara Sea


petm

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Re: The 2019 melting season
« Reply #4960 on: July 30, 2019, 05:59:05 AM »
Southerlies over the past 2 days have widened the gap off NE Greenland to an alarming degree

Are we seeing this year an end to the last refuges of thick ice?

Frivolousz21

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Re: The 2019 melting season
« Reply #4961 on: July 30, 2019, 06:20:14 AM »
That slushy swirling ice in the ESS has really slowed things up.

That night all melt out.

But it's preventing the ESS from being a staging point to crush the CAB.

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petm

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Re: The 2019 melting season
« Reply #4962 on: July 30, 2019, 06:22:09 AM »
Could any climate model aficionados comment on whether (no pun intended) the model runs are responding to the rapid increases in open ocean (and should we expect them to)? Or if they are not responding, is there a noticeable systematic divergence between forecasts and observed weather?

Not sure if this is a practical question, but the circumstances seem to warrant it...

Edit: E.g. The attached forecast seems to respond, with the little remaining jet following the *current edge of the Pacific ice (*which will likely have moved considerably by the time of the forecast arrives in over a week).
« Last Edit: July 30, 2019, 06:46:28 AM by petm »

bbr2314

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Re: The 2019 melting season
« Reply #4963 on: July 30, 2019, 06:26:51 AM »
That slushy swirling ice in the ESS has really slowed things up.

That night all melt out.

But it's preventing the ESS from being a staging point to crush the CAB.
What are you talking about? The ESS has melted out faster than ever before. "Slowed things up" is still FASTER THAN EVER BEFORE so I think your verbiage here is silly and wrong. And if you have been paying attention to forecasts / actual weather, the CAB just took a bullet and it was completely independent of what is happening in the ESS (originating via North America / the CAA). So ultimately your statement here is doubly untrue.

(I don't mean to come across as antagonistic here and I genuinely enjoy your posts, this is just my opinion).

petm

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Re: The 2019 melting season
« Reply #4964 on: July 30, 2019, 06:28:47 AM »
So ultimately your statement here is doubly untrue.

Does that mean it's true? Jk hahaha  ;D

Frivolousz21

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Re: The 2019 melting season
« Reply #4965 on: July 30, 2019, 06:33:05 AM »
That slushy swirling ice in the ESS has really slowed things up.

That night all melt out.

But it's preventing the ESS from being a staging point to crush the CAB.
What are you talking about? The ESS has melted out faster than ever before. "Slowed things up" is still FASTER THAN EVER BEFORE so I think your verbiage here is silly and wrong. And if you have been paying attention to forecasts / actual weather, the CAB just took a bullet and it was completely independent of what is happening in the ESS (originating via North America / the CAA). So ultimately your statement here is doubly untrue.

(I don't mean to come across as antagonistic here and I genuinely enjoy your posts, this is just my opinion).

That doesn't matter.

It needs to be clear blue open water by now and it's not.

There is no chance for a big SST build up in the ESS.

And melt out is subjective.

I bet there will be swirls of ice well after the satellites say it's ice free.

And I bet SSTS don't do bleep because of it.

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Ice Shieldz

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Re: The 2019 melting season
« Reply #4966 on: July 30, 2019, 06:38:44 AM »
I remember last melt season FishOutOfWater commenting on how the cool/cloudy summer phenomena we've experienced for the last few years was not a trend at all climatologically because it was such a short time blip. His caution about banking on the cool summer trend seems to be coming to fruition.

One trend is holding up at a climatological scale -> the winters have lost their winter power so we haven't got much left to work with when the roll of the dice like it is this year ain't in our favor. House always wins.

Thank you to Zach for another excellent plot

bbr2314

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Re: The 2019 melting season
« Reply #4967 on: July 30, 2019, 06:49:30 AM »
That slushy swirling ice in the ESS has really slowed things up.

That night all melt out.

But it's preventing the ESS from being a staging point to crush the CAB.
What are you talking about? The ESS has melted out faster than ever before. "Slowed things up" is still FASTER THAN EVER BEFORE so I think your verbiage here is silly and wrong. And if you have been paying attention to forecasts / actual weather, the CAB just took a bullet and it was completely independent of what is happening in the ESS (originating via North America / the CAA). So ultimately your statement here is doubly untrue.

(I don't mean to come across as antagonistic here and I genuinely enjoy your posts, this is just my opinion).

That doesn't matter.

It needs to be clear blue open water by now and it's not.

There is no chance for a big SST build up in the ESS.

And melt out is subjective.

I bet there will be swirls of ice well after the satellites say it's ice free.

And I bet SSTS don't do bleep because of it.
I feel like you are making up hypotheticals for a BOE / etc when we have reality unfolding in front of us disproving these notions (previously you were going on about how the CAA melt out is crucial to heat entering the CAB, yet here we are a few weeks later and the CAB took a direct hit, worst ever for this time of year, despite relatively intact CAA). Ultimately we will see what happens as it unfolds.

petm

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Re: The 2019 melting season
« Reply #4968 on: July 30, 2019, 06:54:28 AM »
Regarding the swirls, surely those areas have begun to at least increase the amount of water vapor in the atmosphere above, even if they are still dampening the rise in ssts (for a few more days)...

bbr2314

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Re: The 2019 melting season
« Reply #4969 on: July 30, 2019, 06:58:52 AM »
Regarding the swirls, surely those areas have begun to at least increase the amount of water vapor in the atmosphere above, even if they are still dampening the rise in ssts (for a few more days)...
The swirls will last another week at most IMO.

PS, here are the last three days compared to 2012 (well, 7/25-27). You can see that the difference WHERE IT MATTERS (i.e. where ice survived in 2012) is much worse in 2019.

It would be ideal to compare all of July, but we will be able to do that shortly as well (ESRL data should be out by 8/2 for the month).


petm

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Re: The 2019 melting season
« Reply #4970 on: July 30, 2019, 07:12:58 AM »
Yeah... what happens if 2019 shrinks like 2012, but also detaches (remains detached) from Greenland / CAA. Could the entire pack begin to rotate??

epiphyte

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Re: The 2019 melting season
« Reply #4971 on: July 30, 2019, 07:13:59 AM »
Are we seeing this year an end to the last refuges of thick ice?

Yes - they have vanished now. For my money, they were largely illusory last year - but the models (esp. PIOMAS) hadn't caught up to it yet. It's a long time since either they or the various remote-sensing measurements were calibrated with actual (e.g. submarine) observations.

In other words, We're well into the realm where "You don't know what you've got till it's gone".

I don't have any prediction on what the official area/extent numbers are going to look like this year, and I see little value in speculating on the subject - but I'm >99% certain that on Sep 5th the actual volume of ice in the northern hemisphere will be lower than it has been on that date at any time since humans learned that the Earth orbits the Sun (as opposed to the other way around).

The above having been said, I recall in 2016 thinking in late August that two more weeks of melt would have resulted in a dramatically different picture from the POV of area/extent. Here we are now in late July, and the texture of the whole thing looks the same as it did then - but three weeks earlier.

So in other, other words: 'Get ready for a surprise'


 

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Re: The 2019 melting season
« Reply #4972 on: July 30, 2019, 07:23:17 AM »
What a difference 2 weeks makes.
Beaufort, 76.62, -165.12 upper right, 72.41, -140.43 lower left.  Somewhere between 600 & 700,000km2.

(Edit) Keep in mind this is "relatively" low latitude.  Insolation in two weeks will not be dropping like a rock here  the way it will north of 80.  Most of the ice in the 7/29 image, if not all, should be gone, unless it is replaced by export from the CAB or CAA.
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jdallen

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Re: The 2019 melting season
« Reply #4973 on: July 30, 2019, 07:34:50 AM »
ESS - Different region, similar area, slightly longer time span - 7/12/2019 jumping to 7/29/2019. 
73.90, -160.05 upper right
73.42, -173.50 lower left

Again, virtually all of the ice in the later image should be gone in two weeks, as the region in question will still have fairly high levels of insolation and significant momentum.

Keep in mind, most of the lower image, as awful as the ice looks, is still 30% coverage in so far as extent is concerned.  Area shown here is about 500,000km2.
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jai mitchell

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Re: The 2019 melting season
« Reply #4974 on: July 30, 2019, 07:46:59 AM »
I remember last melt season FishOutOfWater commenting on how the cool/cloudy summer phenomena we've experienced for the last few years was not a trend at all climatologically because it was such a short time blip. His caution about banking on the cool summer trend seems to be coming to fruition.

It was a boost in aerosol intrusion into the Arctic.  The current economic cycle has curtailed this cooling effect significantly this summer.
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jdallen

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Re: The 2019 melting season
« Reply #4975 on: July 30, 2019, 07:47:29 AM »
Laptev/Kara covering the FJL gap to the Barents.
This is a larger area - about 4,000,000km2.
First image from the 16th, second the 29th of July 2019.

A lot of the ice in the lower left is above 80N, and will see rapidly decreasing insolation over the next 10 days.

Not as much will disappear from this region, but the portions to the top and upper right will likely be gone in 2-3 weeks.

72.53, 98.21 upper right
84.90, -135.53 lower left
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bbr2314

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Re: The 2019 melting season
« Reply #4976 on: July 30, 2019, 07:53:05 AM »
I remember last melt season FishOutOfWater commenting on how the cool/cloudy summer phenomena we've experienced for the last few years was not a trend at all climatologically because it was such a short time blip. His caution about banking on the cool summer trend seems to be coming to fruition.

It was a boost in aerosol intrusion into the Arctic.  The current economic cycle has curtailed this cooling effect significantly this summer.
I strongly agree with this conclusion. I was refuted a month or two ago by posters who said China's GDP #s were still OK, but we all know Chinese numbers are garbage. The economies that are actually reliably reporting #s in the region are now all in recession, and the reported #s lag actuality by 3-6 months, meaning this is (IMO) the best explanation for what has occurred this year. It has been rather remarkable, and by a mile -- the only logical conclusion IMO is that we have seen a major decrease in SO2 / aerosol emissions concurrent with the lull in the economic cycle (particularly derivative of declines in HEAVY industry, but also probably piggybacking on increasing western reliance on green energy / concurrent declines in aerosols due to that transition).

It is not coincidental that 2007 preceded 2008, and 2011-12 also occurred at the height of the economic downturn. Some of it is clearly noise, but I think this is beyond noise.

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Re: The 2019 melting season
« Reply #4977 on: July 30, 2019, 08:16:19 AM »
I remember last melt season FishOutOfWater commenting on how the cool/cloudy summer phenomena we've experienced for the last few years was not a trend at all climatologically because it was such a short time blip. His caution about banking on the cool summer trend seems to be coming to fruition.

It was a boost in aerosol intrusion into the Arctic.  The current economic cycle has curtailed this cooling effect significantly this summer.
I strongly agree with this conclusion. I was refuted a month or two ago by posters who said China's GDP #s were still OK, but we all know Chinese numbers are garbage. The economies that are actually reliably reporting #s in the region are now all in recession, and the reported #s lag actuality by 3-6 months, meaning this is (IMO) the best explanation for what has occurred this year. It has been rather remarkable, and by a mile -- the only logical conclusion IMO is that we have seen a major decrease in SO2 / aerosol emissions concurrent with the lull in the economic cycle (particularly derivative of declines in HEAVY industry, but also probably piggybacking on increasing western reliance on green energy / concurrent declines in aerosols due to that transition).

It is not coincidental that 2007 preceded 2008, and 2011-12 also occurred at the height of the economic downturn. Some of it is clearly noise, but I think this is beyond noise.

Cleaning the air may have more an effect than marginal slowdown in growth.

How China is cleaning up its air pollution faster than the post-Industrial UK

http://blogs.edf.org/markets/2018/05/17/how-china-is-cleaning-up-its-air-pollution-faster-than-the-post-industrial-uk/
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Re: The 2019 melting season
« Reply #4978 on: July 30, 2019, 08:23:44 AM »
Could any climate model aficionados comment on whether (no pun intended) the model runs are responding to the rapid increases in open ocean (and should we expect them to)? Or if they are not responding, is there a noticeable systematic divergence between forecasts and observed weather?

Not sure if this is a practical question, but the circumstances seem to warrant it...

Edit: E.g. The attached forecast seems to respond, with the little remaining jet following the *current edge of the Pacific ice (*which will likely have moved considerably by the time of the forecast arrives in over a week).

Outside the question of the jet, there is also others consequences. Models are showing more influence of diabatic process and warm core process in cyclogenesis for example. The european guy (I don't bother wit GFS) this morning is forecasting TCU/CB in Beaufort around 72H with the weak low, and some warm core process definitively going on.

oren

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Re: The 2019 melting season
« Reply #4979 on: July 30, 2019, 08:36:00 AM »
What are you talking about? The ESS has melted out faster than ever before. "Slowed things up" is still FASTER THAN EVER BEFORE so I think your verbiage here is silly and wrong.
Sadly that is not true. ESS area is right at the level of 2017 and 2015 for the date. Both years slowed beyond this point. I don't expect 2019 to slow down here, but I do expect CAPS statements to be factual in their details.

I feel like you are making up hypotheticals for a BOE / etc when we have reality unfolding in front of us disproving these notions (previously you were going on about how the CAA melt out is crucial to heat entering the CAB, yet here we are a few weeks later and the CAB took a direct hit, worst ever for this time of year, despite relatively intact CAA). Ultimately we will see what happens as it unfolds.
IIRC Friv's CAA statement was that to get a new record the easier more southerly ice in the CAA must be cleared, rather than leaving the heavy lifting to the more northerly CAB. But maybe there was another CAA statement I missed.

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Re: The 2019 melting season
« Reply #4980 on: July 30, 2019, 08:43:55 AM »
The economies that are actually reliably reporting #s in the region are now all in recession

This is OT here, but that is so not true. Recession is defined as two quarters with negative GDP growth. We do NOT have that. In fact eg. the two biggest player around China, Korea and Japan both grew 2.1% y/y

https://asia.nikkei.com/Economy/Japan-s-GDP-surprises-with-2.1-rise-in-first-quarter

q/q figures here:

https://www.investing.com/economic-calendar/gdp-119
https://www.investing.com/economic-calendar/south-korean-gdp-471

Killian

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Re: The 2019 melting season
« Reply #4981 on: July 30, 2019, 10:02:51 AM »
(EDITED: That was a horrific mess that was! It was badly rushed bc students came early. Sorry. Fixed a math error, too.)

Quote
7/28/2019 stands at 6.19M km sq. 2019 needs an increase of < 10k km sq. for a record low on this date.

Nailed one. Came in at 114k, specifically. Yay, in a sick-to-the-stomach sort of way, eh?

7/30/2012 stood at 6.13M km sq. on this date , a drop of 70k.
7/29/2019 stands at 6.08M km sq., a record low for the date. 2019 needs an increase of < 50k km sq. for a record low on this date.

Analysis:
Quote
I'm giving priority to the winds coming off of Greenland, over the CAA and up the Fram/over Svalbard and calling a solid -120k +/-15k.

I see little reason to adjust this after perusing the various images/data. Call it 105k +/-10k, so around 5.975M km sq.

Updated: I was looking at NullSchool again and over the time frame of the 30th the heat just gets higher and flows ever deeper into the basin, all over the place. I can't see the 30th being lower than the 29th under those conditions even though winds seemed stronger on the 29th.

Revise to 120k +/-10k, so around 5.96M km sq.

BONUS: I've developed a way to convert JAXA<>NSIDC when one or the other is missing. Since NSIDC comes in much later, we can have some Fun With Numbers: Calling the NSIDC for 7/29 at 6.48M km sq. (Damn. Yet another error: 6:.48, not 6.46. Never post just before teaching...)

-----------------------------------

8/10/2012 stood at 4.94M km sq.
2019 needs an average daily drop of > 94.67k km sq. for a record low on this post-GAC date. (12 days)

9/15/2012 stood at 3.18M km sq. on this date.
2019 needs an average daily drop of > 60.03k km sq. for a record low on this date. (48 days)

Comment: If we keep getting century drops, we're going to hit both of these. Interestingly, 2012 also had a few days of fairly big losses in late July, then a pause, then the GAC and the 9 Days That Ate The Ice.

Would be cool to see the pattern repeat, just because patterns are cool - but also are often red herrings, but I suppose we should expect a much calmer Aug 2-10 than in '12.

Getting closer....
« Last Edit: July 30, 2019, 04:12:26 PM by Killian »

Zeug Gezeugt

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Re: The 2019 melting season
« Reply #4982 on: July 30, 2019, 10:32:54 AM »
Normally I'm eager to see the destruction, but honestly this is getting scary.

Anyone care comment on the North African heat bomb that roasted Europe and has just lit up Greenland and Ellesmere heading for the Lincoln Sea?

be cause

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Re: The 2019 melting season
« Reply #4983 on: July 30, 2019, 10:42:18 AM »
Bordeaux yesterday , Brussels tomorrow , Bergen on Friday then Spitzbergen ? The heat marches north ..  b.c.

p.s.  the latest gfs run has the Arctic pretty much frost-free for the next 2 weeks .

comment from a week ago .. ok .. the heat marched a little west too .. Gerontocrat is and will be dealing with the consequences on the Greenland thread and there has been much associated discussion across the forum .. b.c.

 ps . that looks like a pretty frost-free Arctic too ..
 
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

be cause

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Re: The 2019 melting season
« Reply #4984 on: July 30, 2019, 10:50:16 AM »
Note to Oren .. Geronto's  NSIDC graph yesterday showed ESS this year in a clear lead .. bbr was being factual with his CAPS .. but facts vary .. not just in Trump's world .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

Zeug Gezeugt

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Re: The 2019 melting season
« Reply #4985 on: July 30, 2019, 10:52:07 AM »
there has been much associated discussion across the forum .. b.c.

Yes bc, I too have been reading and there are plenty of forecasts in the past tense but no present discussion as yet of the current 00z events.

I'm rather more interested in current interpretations of the unfolding melting event, do you have one?

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Re: The 2019 melting season
« Reply #4986 on: July 30, 2019, 11:51:33 AM »
Note to Oren .. Geronto's  NSIDC graph yesterday showed ESS this year in a clear lead .. bbr was being factual with his CAPS .. but facts vary .. not just in Trump's world .. b.c.
Thanks b.c., I didn't think to check that, though it seems I was correct anyhow. NSIDC area chart shows the same behavior, 2015 and 2017 on same leading path as 2019, with 2012 and 2016 coming from behind and overtaking them soon.

be cause

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Re: The 2019 melting season
« Reply #4987 on: July 30, 2019, 12:08:56 PM »
Sorry Oren .. of course G. leaves out the 'non-significant' years like 2015 and 2017 .. which then leaves 2019 well ahead .. or dashing toward insignificance itself (unlikely).

 Z G .. I'll let the event unfold further .. it is a little early as yet . However the 00.00 gfs forecast for 66h was the first I have ever seen with >20'C forecast for both East and West coasts of Greenland . b.c.

ps .. of course reliance on any one forecast atm is not without it's risks .. bbr's gfs 980 mb low has  been replaced by pressure @ 1020mb in the next forecast ..
« Last Edit: July 30, 2019, 12:34:52 PM by be cause »
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

Sterks

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Re: The 2019 melting season
« Reply #4988 on: July 30, 2019, 12:23:48 PM »
July 22 to July 29 gradual shift. UH concentration.
A 'rubble' extent very distinguished from a more solid pack

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Re: The 2019 melting season
« Reply #4989 on: July 30, 2019, 02:03:12 PM »
Compared to the past few days of exceptionally high movement, drift slowed down today (but not completely).

http://osisaf.met.no/p/osisaf_hlprod_qlook.php?prod=LR-Drift

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Re: The 2019 melting season
« Reply #4990 on: July 30, 2019, 02:14:25 PM »
The image of bremen for yesterday can tell us quite a bit on where the melting season is headed.
We are having strands of weakness ( low concentration) that are now reaching 80 north in the beaufort chuchki junction. Similarly, whilst a huge chunk of the ess is now very thinned out, its dispersion starts affecting the pack above 80 north too in places.
The laptev bite has steadily progressed, both in depth and towards the atlantic, avoiding the compaction point of the siberian islands. This could mean an arc of free water from the laptev to the kara, with a blip of ice near those islands.
The atlantic side is resisting suprisingly well, with little movement, probably an indication of weaker warm currents than usual, but there are still weaknesses north of the fjl. If we see a colder end of season here, we won t see a retreat far off from svalbard.
On the other hand, the spectacular greenland retreat, probably pushed by a mix of recurring currents and exceptional weather, might deepen the blow inside the pack, and enlarge the already growing crack. This is coupled with some lower concentration between the nares and the pole, hopefully just meltponding, although days old smos data indicates it might not be.  If it is real we could see the melt of the cone leading from the north pole to nares and, subsequently, a full lift off of the pack from the caa greenland garlic press.
The caa is steadily melting, but the wider channels in the north west seems to remain solid. This extra area might be enough to avoid a new record or to only better the record by a short amount, the latter being what i am leaning towards.
The strongest areas are the arm “south” of beaufort, just next to the caa, but the crack forbids it from replenishing the northern caa fully, and it stable only till the 76-78 north, the cone of compression towards svalbard, some of the north pole, and the siberian islands point of compaction. Three of them are or will be for certain subject to side melt (exception is north pole) while both beaufort and north pole are getting thinned by dispersion. Those are the areas (minus the siberian islands compaction point) to monitor to see whether we will get a new record or even a near boe (still low probability). If a gac destroys one or more of those areas, it is sealed.
Meanwhile the hudson artifacts continue.

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Re: The 2019 melting season
« Reply #4991 on: July 30, 2019, 02:30:13 PM »

BONUS: I've developed a way to convert JAXA<>NSIDC when one or the other is missing. Since NSIDC comes in much later, we can have some Fun With Numbers: Calling the NSIDC for 7/29 at 6.46M km sq.


The 7.28 NSIDC sea ice extent value was 6.405 millions of square kilometers. Are you predicting an increase of 55 thousand square kilometers for 7.29? Or is this prediction, the five day trailing average for 7.29, will produce a value of 6.46 millions of square kilometers? It seems a bit superfluous to predict a 5 day trailing average, rather than the daily value.
« Last Edit: July 30, 2019, 02:44:00 PM by weatherdude88 »

Killian

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Re: The 2019 melting season
« Reply #4992 on: July 30, 2019, 02:48:48 PM »
The 5-Day is what is reported and posted via Charctic.

I get good accuracy with the daily, but excellent accuracy with the 5-day. Given it's a near-useless mathematical conversion, let's maybe not take it too seriously.

BTW, it was 6.48, not 6.46. Made no difference: Came in at 6.47. The conversion shows the following accuracy so far, if anyone is impatient for data one direction or the other at some point:

NSIDC to JAXA Conversion Accuracy         

Error range   Cumulative %   # in range       %
      0M km sq       0.17                  8      0.17
0~10M km sq       0.52                   16      0.35
0~20M km sq       0.76                   11      0.24
0~30M km sq       0.85                     4      0.09
0~50M km sq       0.91                     3      0.07
0~100M km sq       1.00                     4      0.09


JAXA to NSIDC Conversion Accuracy         

Error range   Cumulative%      # in range     %
      0M km sq       0.24                  11           0.24
0~10M km sq       0.54                  14           0.30
0~20M km sq       0.78                  11           0.24
0~30M km sq       0.87                   4           0.09
0~50M km sq       0.93                   3           0.07
0~100M km sq       1.00                   3           0.07
« Last Edit: July 30, 2019, 04:39:07 PM by Killian »

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Re: The 2019 melting season
« Reply #4993 on: July 30, 2019, 03:38:07 PM »
Compared to the past few days of exceptionally high movement, drift slowed down today (but not completely).

http://osisaf.met.no/p/osisaf_hlprod_qlook.php?prod=LR-Drift

I got curious how much drift proportionally contributes to melt extents reported when I saw a 60km movement in 9 days in the kara sea ice . That sea is around 500km wide at the current edge (correct me if i'm very off), so a crude 30k m2 displacement occurred?
https://go.nasa.gov/2KiREk6
Attachment: 21-30JulyWorldview.png

NSDIC MASIE 4km extent data shows a 65k drop from 21 to 28 July in the Kara sea. If the drift is not included in these number, it would add 50% to the melt speed.

Click to play drift gif to make sense of the distance and direction the ice moved.
Attachment: arctic-drift-21-28July.mp4

RoxTheGeologist

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Re: The 2019 melting season
« Reply #4994 on: July 30, 2019, 04:02:46 PM »
Still a little extreme.
Yes, it sure is weird. I also checked SST, and they show an increase all over the place. 4°C may be some exaggeration from me, but the temperature went from -1.5°C to above freezing in most places, and the winds are blowing the ice straight into all that hot water. If you look at the winds in the coming days, it looks like a giant hand is pushing the entire pack away from Greenland, straight into hot water...

https://earth.nullschool.net/#2019/07/31/1200Z/wind/isobaric/1000hPa/orthographic=-44.09,94.09,1829/loc=-45.617,84.295

I thought satellites could only measure the top 1/10 mm of the ocean. Perhaps a still warm day with little mixing?

FishOutofWater

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Re: The 2019 melting season
« Reply #4995 on: July 30, 2019, 04:43:53 PM »
Zach Labe aka "Blizzard" on this blog has a recent paper on the effects of sea ice loss on the atmospheric circulation. It turns out that the QBO, an alternating pattern of tropical westerly to easterly winds and back in the mid-stratosphere affects the atmosphere's response to the lack of sea ice in the Barents - Kara sea region. That means that there will tend to be alternating Arctic oscillation anomalies from one year to the next.

There's other stuff going on, especially the transport of heat into the Labrador sea region and the effects of melting ice on the overturning circulation in the subarctic seas. Pulses of ocean heat are followed by increased amounts of meltwater. This effect helped the Arctic ice recover after the very bad years for ice from 2007 to 2012. Unfortunately, another pulse of heat is now slamming the ice.

A cool pool formed in the subpolar gyre around Greenland after the extreme melt years of 2010 and 2012. Storms in the summer kept it from being hidden by a thin layer of warm fresh water.

High pressure over Greenland this summer has coupled with the return of warm water into the Labrador and Greenland seas. The cool anomaly has pushed south to the storm track across the Atlantic.

A reduction of particulates in China is not driving the patterns we are seeing now in the Arctic as far as I know. We just had a weak El Niño which has caused global temperatures to rise. A reduction in particulates in Asia will have effects on the atmospheric circulation over longer time periods but I think they are lost in the noise of El Niño on the scale of one or two years.

I expect increasingly erratic weather from one year to the next and on longer time scales as ice melts and the ocean and atmospheric circulation patterns respond to melt pulses.

SimonF92

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Re: The 2019 melting season
« Reply #4996 on: July 30, 2019, 05:40:38 PM »
FOoW gives a great summary of that article but being a bit of a sucker for papers, I found the publication here;

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GL083095

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Re: The 2019 melting season
« Reply #4997 on: July 30, 2019, 05:52:04 PM »
First of all the image is awesome.   Sure sign of the times.

But it shows the ESS once again holding on long enough to not be a player in driving melt in August.

The ESS is super shallow.

If it was open water being exposed to the June/July sun it would warm up into the 10-15C range with ease along the CONTENENTIAL shelf.

Maybe above 15C.

I believe that will happen.   Who knows when. But it will bring more issues than ice loss.
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Re: The 2019 melting season
« Reply #4998 on: July 30, 2019, 05:52:17 PM »
This may not turn out to be a record year for areal destruction of CAA ice, but that doesn't mean the situation isn't grim. The Peary and Sverdrup Channels look particularly weak, and there's clear evidence of southward transport via Massey Sound. The Maclean Strait doesn't look much better. The most significant bright spot is probably the northwestern PGAS - Wilkins Strait - Ballantyne Strait sector; this fared uniquely poorly in 2012, and had some struggles in 2016, but seems to be holding firm for now. If the Crack is the new normal, though, that won't be the case long term.

North of Ellesmere, ice just keeps spalling away from shore. I think there's a very real possibility that we may lose the Peterson and Milne Ice Shelves (although Sersen and Ward Hunt are marginally more protected). This should probably be expected; the remnants of the Ellesmere Ice Shelf have been gradually failing since around 2000.

And while Greenland is outside of my focus area, the huge extent of open water -- from north of Wandel Sea all the way to the edge of the Lincoln -- is surprising, as is the speed at which the pack ice there is dispersing. In other years, the massive meltwater pulse just generated when the ice plug failed on the Frederick Hyde Fjord would have had an impact on the ice; this year, it just dumped into open water...

The mechanics of export mean that the Lincoln Sea isn't going to clear or anything like that. But outside of the Lincoln, I don't see any place between the Chukchi and the Wendel where the CAB pack is still attached to coastal fast ice.

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Re: The 2019 melting season
« Reply #4999 on: July 30, 2019, 06:07:59 PM »
I don't see any place between the Chukchi and the Wendel where the CAB pack is still attached to coastal fast ice.

I am referring to this phenomena collectively as the CAB-COW. For CAB-Coastal Open Water. Having spread to Greenland, NAC doesn't cover it any more and at some point it becomes bigger than a crack.