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RikW

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Re: The 2018 melting season
« Reply #2250 on: July 20, 2018, 12:12:55 PM »
Isn't the temperature because of the ice? As long as there is ice, it's hard for the temperature to get much above the melting point, because all the heat is going into the ice. And in the summer the temperature is always around/ slightly above melting point, so it can't get a lot warmer yet.

Or is that too easy?

SimonF92

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Re: The 2018 melting season
« Reply #2251 on: July 20, 2018, 12:27:04 PM »
Isn't the temperature because of the ice? As long as there is ice, it's hard for the temperature to get much above the melting point, because all the heat is going into the ice. And in the summer the temperature is always around/ slightly above melting point, so it can't get a lot warmer yet.

Or is that too easy?

Yes that's correct, the ice acts as a thermal buffer. We will only see temperatures significantly greater than the stable summer mean (+40 years recording [DMI]) further north than the 80th parallel when there is no longer ice left to melt out.
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uniquorn

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Re: The 2018 melting season
« Reply #2252 on: July 20, 2018, 03:22:45 PM »
For 2018 the thing that REALLY surprises me is the Bering sea.  The straight never fully froze over, and was open in February. The ice edge was so far back from what it normally is.  Many articles were written even outside of sea ice geek circles about how unusual it was.
But the ice edge has moved back so incredibly slowly in the melting season it's getting close to normal there. What the heck happened?  Where did all that extra insolation go?  Was that heat shuffled off somewhere else (like out?)  I was almost sure all those warm bering sea waters would cause all kinds of melt and it absolutely didn't materialize.
I think one of the reason is that the two adjacent Seas to Chukchi Sea are the Beaufort Sea and the ESS, which both were very laggardish this year. So a clockwise rotation would push thick ice packs from the Beaufort Sea towards the ice edge and a counterclockwise rotation (as it seems to be now) will push excess ice from ESS towards the ice edge.
Bering has warmed much in the melting season (SST is up to 15°C in some of the bays on both sides). We have no thread for the freezing season 2018/2019 but I assume that freezing in the Bering Sea will be delayed very much this coming winter, and the situation for next spring will be comparable to 2018.
Uni-Hamburg AMSR2 concentration, pacific side, for this melting season.
A significant amount of ice from the Beaufort appears to have melted in the Chukchi.
Somewhat less from ESS.
Edit:More warm winds across the chukchi from the Pacific are forecast for tomorrow.
« Last Edit: July 20, 2018, 03:28:50 PM by uniquorn »

FishOutofWater

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Re: The 2018 melting season
« Reply #2253 on: July 20, 2018, 04:07:20 PM »
Ice and ice water (-1.8C) obviously buffer the temperature of the Arctic but this summer's low temperatures and slow melt season are caused by the stormy weather associated with the positive Arctic Oscillation. High pressure over the central Arctic causes ice compaction near the center of the high. Clockwise winds around the high cause upwelling of warm Atlantic layer water along the shelf margins of the Beaufort sea. This summer that isn't happening. Instead, storms are welling up cold fresh water from inside the Beaufort gyre.

oren

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Re: The 2018 melting season
« Reply #2254 on: July 20, 2018, 04:11:08 PM »
Thanks for the animation uniquorn. I think two major factors affected this year's pacific sector melting season, beyond the poor winter refreeze and early melt onset in the Bering and Chukchi, which were a cause of high expectations that did not (yet) materialize.
The first factor is that chain of old MYI floes identified by A-Team on ASCAT that came all the way from the thick ice repository north of the CAA, which I think protected the left/southern flank of the ice in the Chukchi for quite a while, and only recently melted out (if I read your animation correctly). Now that the way is clear, melting could proceed more quickly should the weather cooperate.
The second factor is the frequent export of major ice fields from the CAB to the Beaufort and Chukchi this season, also seen nicely in your animation, which I think is the main cause of the Beaufort being such a laggard this year. But it's gutting the central pack, which may or may not have an effect in August.
All in all, I think the season is not over yet.

gerontocrat

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Re: The 2018 melting season
« Reply #2255 on: July 20, 2018, 04:20:56 PM »
JAXA Sea Ice thickness 19 July image attached.

To what extent are these thickness images reliable in summer? (or even in winter?)

I also attach the NSIDC Concentration image for 19 July.

Some indication of a low concentration band in the same place as in JAXA's image.
« Last Edit: July 20, 2018, 04:33:59 PM by gerontocrat »
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uniquorn

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Re: The 2018 melting season
« Reply #2256 on: July 20, 2018, 09:17:26 PM »
Thank you for the prognosis Oren. As you are probably aware, floes of MYI still survive in the Beaufort, though the orderly chain is disrupted. Jul13 was the most recent clear day to show some of them.
Worldview terra/modis true color jul13 and 19.

A-Team

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Re: The 2018 melting season
« Reply #2257 on: July 20, 2018, 10:36:21 PM »
Quote
this summer's low temperatures and slow melt season are caused by the stormy weather associated with the positive Arctic Oscillation. High pressure over the central Arctic causes ice compaction near the center of the high. Clockwise winds around the high cause upwelling of warm Atlantic layer water along the shelf margins of the Beaufort sea. This summer that isn't happening. Instead, storms are welling up cold fresh water from inside the Beaufort gyre.
Not sure what years you are referencing, but for 2017-18 this analysis seems completely inconsistent with OSI-SAF sea ice motion data which I have tested over the entire season with motions independently derived from other satellites and other techniques and found quite satisfactory.

The massive ice pack could care less about minor variations in air pressure which are best described over the last few months as chaotic with *no* persistent pattern. It is the boundary layer winds that translate, rotate, compress, disperse and export ice.

These winds cannot be derived by air pressure over the Arctic Ocean alone because they depend on longer-range gradients. Worse, the boundary layer forces are not effectively predicted by any of the forecast systems because the coupling depends strongly on the largely unknown surface topography of the surface (eg ridges and edges). Even then underwater keels strongly affect coupling of the underside of the ice with sea water and whatever currents it might have.

Air pressure at 850HPa and the AO index are very weak proxies for sea ice kinematics and dynamics; why use them when the real thing is readily available?

http://osisaf.met.no/p/osisaf_hlprod_qlook.php?year=2018&month=07&day=12&action=Today&prod=LR-Drift&area=NH&size=100%25

*tech note* It is very convenient to randomize a time series amimation using ImageJ. If say 9 of these are prepared and shown along side the actual true chronological sequence, if observers cannot reliably distinguish random from ordered, than the time series has no recognizable order or pattern to it and can be termed chaotic, which is the case here (ignoring blue melt progression, just looking at wind vector arrows).

By way of contrast, randomized 78-day series of Ascat during which the Beaufort-Chukchi stringer was setting up are immediately distinguished from the actual time-ordered sequence.

The series here runs for 78 days. Prepare a column of 78 numbers 1-78, another column of 78 numbers provided by the random number generator that comes with every spreadsheet. Then sort the random numbers say in descending order. That will scramble the conventional column. Copy these into a text editor and replace carriage returns with commas. Then paste into Image --> Stack --> Tools --> Make Substack. Repeat with a newly generated set of random numbers.
« Last Edit: July 20, 2018, 11:19:41 PM by A-Team »

magnamentis

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Re: The 2018 melting season
« Reply #2258 on: July 21, 2018, 01:07:23 AM »
Early winter in the Canadian archipelago?

that would be a title for the yellow press and even there i'd comment.

this is my opinion and i hope i was is "nice" enough

as long as we make a season or a climate change from every outlier weather event
deniers find there fodder right where we're trying to document global warming.

after i i've seen snow in july in very much lower latitudes and in one or another place it happens
almost if not each year.

FishOutofWater

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Re: The 2018 melting season
« Reply #2259 on: July 21, 2018, 01:21:10 AM »
A-Team, if you look at the compactness curves you may notice that compactness drops every time a storm moves over the central Arctic towards the CAA this summer. I think you're right that this summer there are many chaotic motions which are cancelling each other out. I agree with this quote:

The massive ice pack could care less about minor variations in air pressure which are best described over the last few months as chaotic with *no* persistent pattern.

It's a well established fact that intense storms like hurricanes leave cool SST tracks because they cause divergence and upwelling. However, I looked at Mercator ocean's model and didn't see obvious effects for the Arctic this summer, probably because the ice covered, cold fresh water inversion layer is not disrupted by relatively fast moving transient storms. The GAC was persistent enough to break the temperature inversions. These transient storms are not.

Both the scientific literature and our observations on this forum indicate that prolonged periods of Beaufort high pressure north of Alaska lead to upwelling of relatively warm water along the shelf margin. That has not happened this summer.

Thanks for the link to the site that tracks ice motion. That's useful, but not what I was writing about. I was writing about divergence and convergence which lead to upwelling and downwelling of ocean water, respectively. The Beaufort high has a pool of relatively fresh water under it because the fresh surface water converges and downwells under the center of the high pressure area.  When they are persistent, pressure patterns have major effects on oceanographic properties. I suspect that this summer's lack of high pressure in the Beaufort sea and central will lead to some loss of fresh water volume from the Arctic ocean this year.
« Last Edit: July 21, 2018, 01:29:00 AM by FishOutofWater »

jdallen

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Re: The 2018 melting season
« Reply #2260 on: July 21, 2018, 07:43:31 AM »
Hmmm.  I wonder if the increase in cloudiness is tied to an increase in overall humidity?
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Re: The 2018 melting season
« Reply #2261 on: July 21, 2018, 10:27:01 AM »
A-Team, if you look at the compactness curves you may notice that compactness drops every time a storm moves over the central Arctic towards the CAA this summer.
Isn't this mainly due to cloudiness interfering with the sensors and giving falsely low concentration readings?  As we discuss several times every year?

Aluminium

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Re: The 2018 melting season
« Reply #2262 on: July 21, 2018, 11:14:31 AM »
July 16-20.

Next update will be in 6 days.

oren

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Re: The 2018 melting season
« Reply #2263 on: July 21, 2018, 12:17:38 PM »
July 16-20.

Next update will be in 6 days.
Thanks again.
I notice the export to the Beaufort continues, this time from the ESS where no coastal ice remains. I also note the growing polynia near NE Greenland, where the ice seems to melt before being exported to the Fram, and the continued "poofing" of Kara ice.
OTOH, it currently seems that the ice in the cetral arctic is rather well protected, which (if true) should help avert an August crash this season.

NeilT

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Re: The 2018 melting season
« Reply #2264 on: July 21, 2018, 12:52:45 PM »
Hmmm.  I wonder if the increase in cloudiness is tied to an increase in overall humidity?

A couple of years ago I posted a link to a study which was looking into the effect of extensive leads and open water in the CAB and how it impacts local weather, local humidity and local precipitation.

The abstract seemed to point to the fact that the more fragmented the pack is, the more humidity you get locally.  They also tracked differences in weather too.  I was more interested in the impact from an early start and how it affected the ongoing melt season, the study was mainly around July and August.
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uniquorn

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Re: The 2018 melting season
« Reply #2265 on: July 21, 2018, 01:54:04 PM »
July 16-20.

Next update will be in 6 days.
Thanks again.
I notice the export to the Beaufort continues, this time from the ESS where no coastal ice remains. I also note the growing polynia near NE Greenland, where the ice seems to melt before being exported to the Fram, and the continued "poofing" of Kara ice.
OTOH, it currently seems that the ice in the cetral arctic is rather well protected, which (if true) should help avert an August crash this season.
Did you mean 'export to the Chukchi continues'?

oren

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Re: The 2018 melting season
« Reply #2266 on: July 21, 2018, 02:18:22 PM »
July 16-20.

Next update will be in 6 days.
Thanks again.
I notice the export to the Beaufort continues, this time from the ESS where no coastal ice remains. I also note the growing polynia near NE Greenland, where the ice seems to melt before being exported to the Fram, and the continued "poofing" of Kara ice.
OTOH, it currently seems that the ice in the cetral arctic is rather well protected, which (if true) should help avert an August crash this season.
Did you mean 'export to the Chukchi continues'?
Just eyeballing the animation, it seems the whole pacific-side pack is drifting roughly westward, with the net result being that ice is pulled back from the ESS coast, and a net import appearing in the Beaufort, while the Chukchi seems to me more as a transit area. It's just a general qualitative interpretation of course.

FishOutofWater

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Re: The 2018 melting season
« Reply #2267 on: July 21, 2018, 05:45:17 PM »
Peter, the ice pack went from highly compact (compared to normal) in late spring to more dispersed than average in mid-July because low pressure areas are dispersive. There are short term effects of clouds on sensors but those effects are gone in a few days.

As A-Team pointed out the net effect of storms and high pressure areas this summer has been to cause chaotic ice motion in much of the Arctic. This is in contrast to many years in the last decade when persistent high pressure brought on early open water in the Beaufort sea and compaction of ice in the central Arctic basin.

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Re: The 2018 melting season
« Reply #2268 on: July 21, 2018, 06:37:32 PM »
Hmmm.  I wonder if the increase in cloudiness is tied to an increase in overall humidity?

I am certain of it but I don't know much.

I believe we are seeing a transition in the Arctic, moving from a low humidity, dry climate with generally cloudless skies to a higher humidity, moist climate with cloudier skies and more precipitation. The increased clouds result in warmer falls and winters as they reduce the amount of heat that radiates into space. They also result in cooler summers as the clouds block and reflect sunlight back into space.

bbr2314

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Re: The 2018 melting season
« Reply #2269 on: July 21, 2018, 06:54:09 PM »
Models have several recurving typhoons over the next ten days. As concentration drops have accelerated area is still holding up. But that won't be the case for much longer. Today, we have another Siberian Smoke Storm arriving per EOSDIS as well.

With ongoing Siberian fires worse than any year since 2012 + an active WPAC typhoon season, the Pacific side of the pack is going to melt out almost entirely by 8/1. The ESS arm is also looking like it will remain proximate / attached to the shoreline. This will become quite obvious when it does not retreat with the rest of the pack as it normally does, instead, huge swaths of the CAB will simply turn blue.

The only area holding up very well this year is the CAA, where Beaufort ice is now flushing.


A-Team

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Re: The 2018 melting season
« Reply #2270 on: July 21, 2018, 08:22:36 PM »
Off on travels for two weeks but here is a teaser/challenge: mp4 the whole melt season weather from nullschool at 3hr intervals or as appropriate, separately for wind and sea level pressure at separate key locations. (Doable manually but calls for some kind of automation.)

The image below takes a hasty look at whether MSLP over the Arctic Ocean 'averages out' evenly over some rolling window time frame to be determined. The image just averages the last ten days of nullschool GFS colors, then applies a contour tool.

Intriguingly, weather from the North Atlantic is pushing contours up the Fram, the Mackenzie doing the same though less convincingly, overall higher pressure on the periphery, lower pressure inside but not over the Beaufort Gyre nor over the North Pole but rather over the Pole of Inaccessibility (which is the center of the circle of maximal possible rotation over water).

magnamentis

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Re: The 2018 melting season
« Reply #2271 on: July 21, 2018, 09:53:32 PM »
Hmmm.  I wonder if the increase in cloudiness is tied to an increase in overall humidity?

IMO that's clearly the case or at least the main driver for persistently more clouds than usual.

Wherestheice

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Re: The 2018 melting season
« Reply #2272 on: July 21, 2018, 11:22:02 PM »
More melting ice leads to higher temps (due to less sunlight reflection) and more water vapor, which = better chance for clouds to form. So for example.....if the Arctic goes ice free free, and there comes a point when the ice doesn’t come back, that leads to less ice melting and the arctic abruptly transitions to a new state. So what if the cloudy summers we are seeing is just a last cry for the arctic before it transitions to a new state. This is just a theory and I’m sure I’m wrong in some of what I said, but it makes sense to me.
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Dharma Rupa

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Re: The 2018 melting season
« Reply #2273 on: July 22, 2018, 12:31:10 AM »
More melting ice leads to higher temps (due to less sunlight reflection) and more water vapor, which = better chance for clouds to form. So for example.....if the Arctic goes ice free free, and there comes a point when the ice doesn’t come back, that leads to less ice melting and the arctic abruptly transitions to a new state. So what if the cloudy summers we are seeing is just a last cry for the arctic before it transitions to a new state. This is just a theory and I’m sure I’m wrong in some of what I said, but it makes sense to me.

I don't know if it is the last cry or not, but I fully agree that when the transition happens it will be permanent (at least as far as we are concerned).  The ice will run out, the freshwater cap will mix, and it will be the end of the old Arctic.  No idea when it will happen, but I don't see where September will matter.


magnamentis

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Re: The 2018 melting season
« Reply #2274 on: July 22, 2018, 02:07:01 AM »
More melting ice leads to higher temps (due to less sunlight reflection) and more water vapor, which = better chance for clouds to form. So for example.....if the Arctic goes ice free free, and there comes a point when the ice doesn’t come back, that leads to less ice melting and the arctic abruptly transitions to a new state. So what if the cloudy summers we are seeing is just a last cry for the arctic before it transitions to a new state. This is just a theory and I’m sure I’m wrong in some of what I said, but it makes sense to me.

without going into details, something along your line of thinking is happening, i see it similarly

Pmt111500

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Re: The 2018 melting season
« Reply #2275 on: July 22, 2018, 12:59:11 PM »
More melting ice leads to higher temps (due to less sunlight reflection) and more water vapor, which = better chance for clouds to form. So for example.....if the Arctic goes ice free free, and there comes a point when the ice doesn’t come back, that leads to less ice melting and the arctic abruptly transitions to a new state. So what if the cloudy summers we are seeing is just a last cry for the arctic before it transitions to a new state. This is just a theory and I’m sure I’m wrong in some of what I said, but it makes sense to me.

without going into details, something along your line of thinking is happening, i see it similarly
Yep, cold continents aren't too cold late in the melting season expunging the waters of the melted arctic continents to drive out the cooler water melted frim ice thus.... The mechanism proposed to abrupt end for sea ice. Thus early guesses for BoE, clouds are likely playing a role here.
Cooling the outside by heat pump.

uniquorn

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Re: The 2018 melting season
« Reply #2276 on: July 22, 2018, 04:27:54 PM »
As there has been so much cloud this melting season, here is uni hamburg AMSR2 ice concentration with Worldview terra/modis true color jul14-21. Some weather effects can be seen on the concentration map. I added a bathymetry map, mostly because I was interested in the feature in the Chukchi close to the alaskan coast.

FishOutofWater

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Re: The 2018 melting season
« Reply #2277 on: July 22, 2018, 06:09:20 PM »
There has been more water vapor coming off the Barents sea as it behaves more like the Atlantic. However, this vapor has fallen as snow over Siberia. The last two winters have been warm over the Arctic ocean, but they have also been very snowy in Siberia. That extra snow has increased the land albedo in spring and slowed the onset of melt season for the sea ice.

uniquorn

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Re: The 2018 melting season
« Reply #2278 on: July 23, 2018, 01:05:11 AM »
Some clearer weather north of FJL shows what may be the last of the Kara tongue melting out at the ice front. Ice to the north appears to be higher concentration with larger floes, though this could just be dispersion at the ice front.

Worldview terra/modis true color, jul12-22 (clear days only)
A-team's provisional ice classification map, may22 (KT is Kara tongue)
Ascat atlantic side, may6-jul22 (day126-202)
« Last Edit: July 23, 2018, 01:10:56 AM by uniquorn »

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Re: The 2018 melting season
« Reply #2279 on: July 23, 2018, 10:35:41 AM »
While I'm waiting for everyone to digest the numbers for the last few days and comment. I though I might ask a simple question. Is Parry Channel likely to open at some stage this season ?

binntho

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Re: The 2018 melting season
« Reply #2280 on: July 23, 2018, 10:53:16 AM »
Well-formed eye of a large low-pressure area more or less in the center of the Arctic Ocean on Worldview today.

The ice seems quite dispersed which would indicate large freedom of movement, with winds in the 30 - 50 km/h range. Wonder what effect this will have on the underlying ocean.

Have tentatively placed the low on today's false-color ice concentration map from uni-bremen.
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Iain

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Re: The 2018 melting season
« Reply #2281 on: July 23, 2018, 01:42:54 PM »
Ice breakup in the CAA North of Cornwallis Island

About a week earlier than in 2017

There are still ice bridges intact at the southern end either side of CI and c. 200km of landfast ice to the north to the CAB

Winds are from the North for the next few days which will add pressure to the ice bridges

It’s one to watch. In the last few years the ice did not become mobile all the way to the CAB until late Sept / early Oct, so there was limited time for export of the thick CAB ice prior to refreeze. If it breaks up earlier, with the prevailing current from the north, there is potential for substantial export of the most resilient ice.
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uniquorn

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Re: The 2018 melting season
« Reply #2282 on: July 23, 2018, 01:53:23 PM »
I wonder why AMSR2 isn't detecting the ice in mid-beaufort. uni-Bremen and uni-hamburg show similar image. Possibly affecting the image further east but too cloudy to see.
AMSR2-UHH and Worldview, jul22
edit:added better comparison
« Last Edit: July 23, 2018, 10:41:18 PM by uniquorn »

bbr2314

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Re: The 2018 melting season
« Reply #2283 on: July 23, 2018, 09:03:36 PM »
Building consensus for trans-continental ridging and resultant severe +500MB anoms and temps over high Arctic. This is D10, the worst projection, but it is already getting underway at the moment. The train of WPAC typhoons appear mostly to blame.


Tor Bejnar

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Re: The 2018 melting season
« Reply #2284 on: July 24, 2018, 12:16:48 AM »
That graph of the Kara Sea sports the cliffiest cliff I have ever seen.  ;D
Neven refers to gerontocrat's graph here.
Believing the Kara "experience" could be repeated in other 'high-ice' basins/seas, even at this latish date, I still wouldn't be surprised of a 2nd or 3rd place finish. 
Arctic ice is healthy for children and other living things.

Neven

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Re: The 2018 melting season
« Reply #2285 on: July 24, 2018, 12:18:58 AM »
You're right, bbr. There is finally some high pressure showing up on the ECMWF forecast maps (I haven't posted any for a while, because they made me sleepy). It politely waits on the Siberian side of the Arctic, and then swoops right into the Beaufort, following a tight, little cyclone to stir things up some more first. According to this graph Gerontocrat just posted on the 2018 sea ice extent and area data thread, there's a lot of ice to be had in the Beaufort:



It'll be interesting to watch how low this melting season can still go, despite quite favourable ice retention conditions so far.
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bbr2314

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Re: The 2018 melting season
« Reply #2286 on: July 24, 2018, 12:55:05 AM »
You're right, bbr. There is finally some high pressure showing up on the ECMWF forecast maps (I haven't posted any for a while, because they made me sleepy). It politely waits on the Siberian side of the Arctic, and then swoops right into the Beaufort, following a tight, little cyclone to stir things up some more first. According to this graph Gerontocrat just posted on the 2018 sea ice extent and area data thread, there's a lot of ice to be had in the Beaufort:



It'll be interesting to watch how low this melting season can still go, despite quite favourable ice retention conditions so far.
According to the graphs there is a lot of *extent* to be had. I would say that there is barely any substantial volume remaining. Much of Beaufort will go poof like Kara.

It is interesting that normally Beaufort melts out from within / the NE Alaskan and NW Canadian archipelagos.

This year, that area has certainly seen melt. But the Pacific front is about to come roaring in (in fact, I believe it already has, we just haven't seen the full effects yet). It is a different dynamic of melt but it could ultimately prove more harmful as the Pacific water is much more saline / has much more potential heat vs. the normal order of ops for Beaufort melt (IMO).

There is some ice in Beaufort that should be resilient (adjacent to CAA). In fact, concentration gains are already or will soon be starting there. But that will come at the cost of most of its periphery.


oren

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Re: The 2018 melting season
« Reply #2287 on: July 24, 2018, 02:34:18 AM »
According to the graphs there is a lot of *extent* to be had. I would say that there is barely any substantial volume remaining. Much of Beaufort will go poof like Kara.
Check out this post. While Kara volume had an above-average volume drop for a while, the Beaufort volume had a below-average drop rate and was still quite substantial on July 15th. The Beaufort has been severely lagging this year in all metrics, mostly due to import IMHO, but also due to a late start to the season.

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Re: The 2018 melting season
« Reply #2288 on: July 24, 2018, 04:27:39 AM »
I've been thinking that the early disappearance of the Bering might have something to do with the slow melt in the Beaufort. Perhaps the early opening and obligatory early water vapor release blocked enough early sunlight to let the Beaufort (and Chukchi) stay thicker for longer. I imagine that the late thick snow also helped.
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bbr2314

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Re: The 2018 melting season
« Reply #2289 on: July 24, 2018, 04:32:47 AM »
I've been thinking that the early disappearance of the Bering might have something to do with the slow melt in the Beaufort. Perhaps the early opening and obligatory early water vapor release blocked enough early sunlight to let the Beaufort (and Chukchi) stay thicker for longer. I imagine that the late thick snow also helped.
Neither Beaufort nor Chukchi has "thick" ice. The early Bering melt allowed PAC intrusion and has created an export situation where Chukchi ice is being transported into Beaufort. Soon there will be nothing left to export and almost all the PAC-peripheral ice will disappear. Look at satellite and thickness maps and this is very plain to see (both HYCOM and Copernicus).

NSIDC is not trustworthy ATM, IMO. The graphs still show ice in St. Lawrence and Okhotosk, where there is actually none in either. The satellites are having problems with cloud coverage.

One final note: the fires are now worsening, and not just in Siberia. EOSDIS shows large smoke plumes now emanating from NW Canada. The European fires aren't too notable on satellite just yet (even though they are already relatively horrific to most years) but we will see what happens when the 591DM heat dome builds into Scandinavia this week. There is going to be an all-out assault from at least three source regions producing billowing clouds of superheated carbon.
« Last Edit: July 24, 2018, 04:37:54 AM by bbr2314 »

bbr2314

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Re: The 2018 melting season
« Reply #2290 on: July 24, 2018, 05:38:19 AM »
I've been thinking that the early disappearance of the Bering might have something to do with the slow melt in the Beaufort. Perhaps the early opening and obligatory early water vapor release blocked enough early sunlight to let the Beaufort (and Chukchi) stay thicker for longer. I imagine that the late thick snow also helped.
Neither Beaufort nor Chukchi has "thick" ice. The early Bering melt allowed PAC intrusion and has created an export situation where Chukchi ice is being transported into Beaufort. Soon there will be nothing left to export and almost all the PAC-peripheral ice will disappear. Look at satellite and thickness maps and this is very plain to see (both HYCOM and Copernicus).

NSIDC is not trustworthy ATM, IMO. The graphs still show ice in St. Lawrence and Okhotosk, where there is actually none in either. The satellites are having problems with cloud coverage.

One final note: the fires are now worsening, and not just in Siberia. EOSDIS shows large smoke plumes now emanating from NW Canada. The European fires aren't too notable on satellite just yet (even though they are already relatively horrific to most years) but we will see what happens when the 591DM heat dome builds into Scandinavia this week. There is going to be an all-out assault from at least three source regions producing billowing clouds of superheated carbon.
It appears Bremen interpreted this post as "Avada Kedavra SEA ICE" because... POOF! Most everything green / yellow will be gone by 8/1.


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Re: The 2018 melting season
« Reply #2291 on: July 24, 2018, 06:10:40 AM »
Yes, the ice pack shape expected for around the extent minimum is starting to emerge.

Looking ahead by 50 days, Andrew Slater's algorithm is now up to 11 September, and so should be fairly close to the expected minimum. Its predicted extent for that date is 4.61 million square kilometers.

Personally, I would believe that prediction as well as any other as I like the method used and the execution also looks good.

Note that the predicted extent is still above that given about 2 weeks ago, of 4.56 million square kilometers already by 29 August 2018. Presumably that reflects weather during the past 2 weeks that has not been favorable for melting the ice.

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Re: The 2018 melting season
« Reply #2292 on: July 24, 2018, 07:29:29 AM »
The animation i posted a few days ago of the Beaufort did not fully convey the sorry state of the ice there. Below is a composite Worldview of July 23rd and an initial 24th satellite pass, plus some contrast adjustment.
« Last Edit: July 24, 2018, 08:11:30 AM by Ice Shieldz »

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Re: The 2018 melting season
« Reply #2293 on: July 24, 2018, 01:22:23 PM »
Yeah, I just checked worldview and the Beaufort is between the worst years this time on the year. Though it's hard to compare between years and value/rank those years.

2016 was the worst year I think, 2008, 2012 and 2015 also very fractured ice/ a lot of open water, but distributed differently.

But 2018 I see almost no larger floes, it's just a large slush with open water between it.

So I won't be surprised if it would go *poof* in the next weeks

bbr2314

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Re: The 2018 melting season
« Reply #2294 on: July 24, 2018, 01:36:43 PM »
Yeah, I just checked worldview and the Beaufort is between the worst years this time on the year. Though it's hard to compare between years and value/rank those years.

2016 was the worst year I think, 2008, 2012 and 2015 also very fractured ice/ a lot of open water, but distributed differently.

But 2018 I see almost no larger floes, it's just a large slush with open water between it.

So I won't be surprised if it would go *poof* in the next weeks
The key differential with the other bad years is the Pacific front. Look at 2016, 2012 -- they both had arms of relatively thick formerly shorefast ice in the Chukchi which withdrew alongside the main pack.

That ice, this year, is either non-existent or is still stuck shorefast in the western ESS. HYCOM actually shows it drifting closer to shore over the next ten days!

This will allow an exceedingly rapid advance of the Pacific front (already happening). There is no thick ice in the way until well into the CAB. There is nothing to stop the push, unlike normal.

Another development to note is the ridging about to balloon over the Atlantic sector. The cold-biased Canadian model has Svalbard reaching heights of 585DM by D5! The GFS and EURO are somewhat more lackluster and only have upper 570s at the same timeframe.



It is going to be quite interesting to see how affected the Atlantic sector is by the impending / ongoing SSTA push from the NATL, which is now arriving in the NE NATL (hence worsening fires in Europe / never-ending heatwave over Scandinavia and other parts). The amount of fuel now present and on its way could delay refreeze for many core sectors well into September.

IMO, the "safest" ice this year is the triangle of MYI N of the CAA. Its periphery will see major melt but it is holding up relatively well even with the onslaught in all other regions. What will that mean for final #s? I am not sure.


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Re: The 2018 melting season
« Reply #2295 on: July 24, 2018, 03:36:34 PM »
According to the graphs there is a lot of *extent* to be had. I would say that there is barely any substantial volume remaining. Much of Beaufort will go poof like Kara.
Check out this post. While Kara volume had an above-average volume drop for a while, the Beaufort volume had a below-average drop rate and was still quite substantial on July 15th. The Beaufort has been severely lagging this year in all metrics, mostly due to import IMHO, but also due to a late start to the season.

to my understanding that exactly means that there is a lot to be had in beaufort. kara was lagging as well for a long time and suddenly started it's free-fall and looking at various sat and concentration images that "may" well happen in large parts of the beaufort-sea, who knows, but the possibility is definitely there iMO

magnamentis

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Re: The 2018 melting season
« Reply #2296 on: July 24, 2018, 03:40:22 PM »
I've been thinking that the early disappearance of the Bering might have something to do with the slow melt in the Beaufort. Perhaps the early opening and obligatory early water vapor release blocked enough early sunlight to let the Beaufort (and Chukchi) stay thicker for longer. I imagine that the late thick snow also helped.

of course, it's like rain and sun, highs and lows, cold and warm spots. depending where they are no the opposite is happening in the neighbourhood and vice versa which is why mentioning cold and warm spots without hinting at the counterpart at the same time are cherry-picking and a yellowpress headline style of statments. at the end it's the global but at least the hemispheric temperature development that is relevant and hints to where we're headed.

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Re: The 2018 melting season
« Reply #2297 on: July 24, 2018, 03:49:18 PM »
BBR, it's interesting that your doomish predictions, uttered by you some weeks ago, ares still valid. While I doubt an extreme outcome, I hink you were spot on concerning the general dynamics of this year.

The arctic stays the most interesting place on earth to watch for global change in less than a lifetime!
The Thunder was father of the first people, and the Moon was the first mother. But Maxa'xâk, the evil horned serpent, destroyed the Water Keeper Spirit and loosed the waters upon the Earth and the first people were no more.

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Re: The 2018 melting season
« Reply #2298 on: July 24, 2018, 03:52:22 PM »
BBR, it's interesting that your doomish predictions, uttered by you some weeks ago, ares still valid.

Well it's a bit like voting for blue ocean every year - sooner or later you're going to be right. Having said that, I was just thinking earlier that bbr is becoming one of those posters worth reading.
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

magnamentis

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Re: The 2018 melting season
« Reply #2299 on: July 24, 2018, 03:55:09 PM »
BBR, it's interesting that your doomish predictions, uttered by you some weeks ago, ares still valid. While I doubt an extreme outcome, I hink you were on spot concerning the general dynamics of this year.

The arctic stays the most interesting place on earth to watch for global change in less than a lifetime!

true that, i mostly share/shared his views, with a few exaggerations less that would have been close to 100% but the main line of thinking i agree.

something like i wrote there:

https://forum.arctic-sea-ice.net/index.php/topic,2223.msg164306.html#msg164306