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Feeltheburn

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Re: The 2018 melting season
« Reply #1850 on: July 01, 2018, 09:49:16 PM »
Sometimes it's good (and encouraging) to just look at the facts/stats rather than engage in speculation and personal animus.

I miss Espen's simple presentation of arctic sea extent data without engaging in hyperbole. To that end, let's consider the NSIDC arctic ice extent data, which shows 2018 ice is holding up better than most years the past decade (so far). I decided to put the years in descending order so we can see better the historical context. Note also that the ice on 30 June 2018 is only 340 km2 lower than 6-30-2001, and 700 km2 lower than 6-30-1995. In addition, note well that ice thickness and compactness are higher than the past 15 years, which favors preservation.

2010 - 9.257
2016 - 9.334
2012 - 9.335
2017 - 9.421
2011 - 9.532
2014 - 9.617
2006 - 9.820
2018 - 9.939
2007 - 9.952
2015 - 10.008
2013 - 10.015
2008 - 10.199
2005 - 10.211
2001 - 10.297
2003 - 10.624
1995 - 10.630
2002 - 10.767
2004 - 10.814




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aperson

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Re: The 2018 melting season
« Reply #1851 on: July 01, 2018, 10:10:36 PM »
Looks like I was right. Thanks for the confirmation!

I hate going OT but this is too clear of an example of confirmation bias to avoid, and it's something we all need to work on here.

You did not make a falsifiable prediction. You implied that the Nares would open at some point soon. Approximately two months later, it did. Was that soon? According to you, it was.

The real issue is that you didn't even bother making a falsifiable prediction in the first place. Whenever you make a prediction, state clearly what success and failure outcomes look like. What is the time frame to "...imminently entail the re-opening of Nares for export"? Is it a day? A month? Some time during the melting season? We'll never know because you never stated the failure criteria for your prediction.

Because you only state the success criteria for your predictions and you hide this success in imprecision, you give yourself a recipe to repeatedly "confirm" your suspicions and lead yourself into chasing down noise.

I'm definitely not an expert in any of the stuff we're discussing here, but I know damn well what a good experiment looks like, and I'm sick of seeing the same cycle of bad hypothesis -> confirmation bias -> worse hypothesis bat deduction going down in this thread.
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bbr2314

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Re: The 2018 melting season
« Reply #1852 on: July 01, 2018, 10:13:36 PM »
Looks like I was right. Thanks for the confirmation!

I hate going OT but this is too clear of an example of confirmation bias to avoid, and it's something we all need to work on here.

You did not make a falsifiable prediction. You implied that the Nares would open at some point soon. Approximately two months later, it did. Was that soon? According to you, it was.

The real issue is that you didn't even bother making a falsifiable prediction in the first place. Whenever you make a prediction, state clearly what success and failure outcomes look like. What is the time frame to "...imminently entail the re-opening of Nares for export"? Is it a day? A month? Some time during the melting season? We'll never know because you never stated the failure criteria for your prediction.

Because you only state the success criteria for your predictions and you hide this success in imprecision, you give yourself a recipe to repeatedly "confirm" your suspicions and lead yourself into chasing down noise.

I'm definitely not an expert in any of the stuff we're discussing here, but I know damn well what a good experiment looks like, and I'm sick of seeing the same cycle of bad hypothesis -> confirmation bias -> worse hypothesis bat deduction going down in this thread.
Your post has nothing to do with sea ice. Please take it to OT. Thanks!

FishOutofWater

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Re: The 2018 melting season
« Reply #1853 on: July 01, 2018, 10:23:21 PM »
Here are several testable predictions. I predict a new El Niño will begin this fall. Ocean heat patterns are very similar to 2015 adjusting for a later onset of El Niño this year than 2015. Sea level patterns indicate El Niño is developing.
https://www.aviso.altimetry.fr/en/data/products/ocean-indicators-products/el-nino-bulletin.html




The weird weather with heat in the U.K and storminess in the Arctic, we have been seeing is consistent with a developing El Niño. Expect the final outcome of this melting season to be pretty similar to 2015. It will be a middling year not threatening any records.
« Last Edit: July 01, 2018, 10:52:37 PM by FishOutofWater »

Aluminium

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Re: The 2018 melting season
« Reply #1854 on: July 01, 2018, 10:32:52 PM »
Addendum to my last... there is an awful lot of moisture either in or heading towards the Arctic.  There may not be sun blasting down or generally above average temperatures, but the latent heat in that air in considerable.
>40 kg/m2. Next week will be curious.

aperson

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Re: The 2018 melting season
« Reply #1855 on: July 01, 2018, 11:00:06 PM »
Yearly comparison of HYCOM CICE thickness for July 1st (June 30th on 2017 for the nearest date with data). Click to animate.

The main remarkable feature continues to be the thickness of ice along the Barents sea into the basin proper. The lack of transpolar drift associated with this also appears to be showing up as thicker ice along the Siberian side of the CAB as well. It appears that 2016 shows similar behavior but is less extreme both in terms of where thickness is lost and gained.
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Re: The 2018 melting season
« Reply #1856 on: July 01, 2018, 11:48:10 PM »
Concerning the tropicaltidbits.com forecasts in the Arctic Basin, I usually check NAVGEM first -though not for any defensible reason.

Anyway, it's showing the lowest pressure bottoming out at 985 hPa, at 00z Tuesday, 3 July - the [36h] forecast. However, nothing below that for all the way out to [180h].

So that storm is probably a solid prediction but any 'wild' forecasts beyond it don't have the support of NAVGEM at least.

FishOutofWater

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Re: The 2018 melting season
« Reply #1857 on: July 01, 2018, 11:51:53 PM »
Interesting comparison of years. If you remember the long chain of thick ice rafted from the CAA around the Beaufort gyre and into the Siberian side of the central Arctic that we saw this winter and early spring you may realize what has happened. There was a regime change in late spring from anticyclonic to cyclonic. There was unusually thick ice on the Siberian side late this spring and the ice was thin on the American side. Over the past 6 weeks strong melting on the Siberian side and weak melting on the American side has led to a large area of relatively uniform thickness across the central Arctic basin.

This "regime change" will help preserve the ice pack this summer.

Neven

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Re: The 2018 melting season
« Reply #1858 on: July 01, 2018, 11:53:45 PM »
We may not see a record low this year, but the ice is still taking a serious pounding.

That's the best one sentence summary of the melting season so far.
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Neven

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Re: The 2018 melting season
« Reply #1859 on: July 02, 2018, 12:17:12 AM »
Let me also add that a cyclone has to tick off several boxes besides low pressure before it can be called a GAC. Yes, there's a cyclone coming with relatively very low pressure, yes, it will do damage, yes, there might even be a second one after that. But they both look to be short-lived, and so I wouldn't call them a GAC.
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oren

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Re: The 2018 melting season
« Reply #1860 on: July 02, 2018, 12:23:33 AM »
Neven, a public request: a poster is hogging this thread to no end, with a lot of the content being idle speculation, extraordinary claims and wild predictions. It's fine as a drizzle but not as a deluge. Measure the total length of posts by the same single poster on page 37 of this thread. Astounding. These posts are generating a lot of responders trying to put some sense into the barrage, and receiving back fully quoted responses, increasing the total volume even more. I find the thread is being derailed. It is supposed to be reporting about actual melting season developments and minimal predictions, short, to the point, all of this is being violated.
There are other threads. Idle chatter thread, season predictions thread, whatever, but please save this thread from becoming a total mess. A single person should not be able to grab so much of this major thread's space (unless at A-Team's level or something like that).
« Last Edit: July 02, 2018, 12:05:50 PM by oren »

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Re: The 2018 melting season
« Reply #1861 on: July 02, 2018, 12:25:31 AM »
That poster has been warned.
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Pagophilus

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Re: The 2018 melting season
« Reply #1862 on: July 02, 2018, 03:23:03 AM »
Here are several testable predictions. I predict a new El Niño will begin this fall.

NOAA agrees: 
ENSO Alert System Status:  El Niño Watch
"ENSO-neutral conditions are present.  Equatorial sea surface temperatures (SSTs) are near-
to-above average across the east-central Pacific Ocean.  ENSO-neutral is favored through Northern Hemisphere summer 2018, with the chance for El Niño increasing to 50% during fall, and ~65% during winter 2018-19."
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf.
   

Pagophilus

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Re: The 2018 melting season
« Reply #1863 on: July 02, 2018, 04:13:00 AM »
I think I saw a version of this movie last month -- the one featuring the June cyclone.   ;)

  .
Addendum to my last... there is an awful lot of moisture either in or heading towards the Arctic.  There may not be sun blasting down or generally above average temperatures, but the latent heat in that air in considerable.
>40 kg/m2. Next week will be curious.
« Last Edit: July 02, 2018, 05:52:38 AM by Pagophilus »

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Re: The 2018 melting season
« Reply #1864 on: July 02, 2018, 05:26:23 AM »
#1855:
Yearly comparison of HYCOM CICE thickness for July 1st (June 30th on 2017 for the nearest date with data)...

If that year-to-year comparison is accurate then it suggests 2018 is likely to be a huge recovery year.

EDIT: or is it an apples-to-oranges comparison between the years? Has the model changed too much? I recall there have been criticisms of HYCOM modelling in the past. Views?
« Last Edit: July 02, 2018, 09:41:12 AM by slow wing »

Frivolousz21

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Re: The 2018 melting season
« Reply #1865 on: July 02, 2018, 07:03:22 AM »
Gfs still brings an epic ahot of heat but unless the progged vortex doesn't move another 400+ miles SW and stay near GIS the airmass wont be over the arctic long enough to really make a difference in the end but that is  strAight filthy heat.

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Iain

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Re: The 2018 melting season
« Reply #1866 on: July 02, 2018, 07:09:33 AM »
Yearly comparison of HYCOM CICE thickness for July 1st (June 30th on 2017 for the nearest date with data). Click to animate.

<edit - oops, the above is a quote, the below is my comment>
Thanks for the animation. My main takeaway is the reduction of thick ice North of the CAA.

In recent years the CAA ice broke up late Sept/early Oct.

This year the breakup in Parry has progressed less far for the time of year than in 14-17, though it has been largely cooler than average so far. One to watch.
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Re: The 2018 melting season
« Reply #1867 on: July 02, 2018, 07:22:49 AM »
#1855:
Yearly comparison of HYCOM CICE thickness for July 1st (June 30th on 2017 for the nearest date with data)...

If that year-to-year comparison is accurate then it suggests 2018 is likely to be a huge recovery year.

Interesting, in those images I see a lot more  + 2m thick ice on the Beaufort side in 2016 and more 1.5m thick Ice in the Barents in 2017 and a lot of generally thinner  ice around 1.5m in the centre in 2018.  That suggests that the defences have already been breached and the ice is under attack from all sides and will fall rapidly as summer continues. But that's just my opinion.
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binntho

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Re: The 2018 melting season
« Reply #1868 on: July 02, 2018, 08:40:13 AM »
Hyperbole and hypersensitivity, wild claims, irrelevant data, way too much garbage. Reading this forum is becoming a pain due to one individual. How many warnings so far Neven?
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Aluminium

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Re: The 2018 melting season
« Reply #1869 on: July 02, 2018, 10:05:37 AM »
I think I saw a version of this movie last month -- the one featuring the June cyclone.   ;)
Yes. However total precipitable water did not surpass 30 kg/m2 above the Arctic Ocean at that time. This heat intrusion will begin in 36 hours. Temperature at 850 hPa will exceed 15°C (up to 19°C) around the New Siberian Islands. Elsewhere this is enough for 30-35°C near surface.

Hyperion

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Re: The 2018 melting season
« Reply #1870 on: July 02, 2018, 10:55:40 AM »
Looks like it has begun already.
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Hyperion

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Re: The 2018 melting season
« Reply #1871 on: July 02, 2018, 11:02:38 AM »
Very interesting weather system. Most of the energy is inbound at high velocity and humidity at high altitude. The cyclone is hot core at 250hPa, but cold core below.
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Neven

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Re: The 2018 melting season
« Reply #1872 on: July 02, 2018, 11:03:22 AM »
Hyperbole and hypersensitivity, wild claims, irrelevant data, way too much garbage. Reading this forum is becoming a pain due to one individual. How many warnings so far Neven?

If you want a perfect echo chamber, go to WUWT (if it still exists).  ;)

Look, I want to give people who go out on a limb some leeway, especially if they post maps and graphs. But I will take action if it leads to too much conflict. People who make extraordinary claims, need to be able to take extraordinary criticism. That is simply how it works.

With that said I will now make my rounds of the ASIG and look at the ECMWF forecast.
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Aluminium

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Re: The 2018 melting season
« Reply #1873 on: July 02, 2018, 11:30:58 AM »
Looks like it has begun already.
This brings a bit of heat along Siberian coast. Main forces will arrive after a pause.

Gray-Wolf

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Re: The 2018 melting season
« Reply #1874 on: July 02, 2018, 01:20:01 PM »
I might just be talking from my Sun kissed UK back garden but this year does appear different to last summer over the basin?

I often wonder just how close we have sailed to seeing record losses unfold over the last 4 weeks of melt season if the 'critical melt out threshold' had been reached and all the FY ice of similar thickness went?

This year I think we might again run into a different seasons end with a lot of ice going out over a period that used to see slow down in losses ( balanced by 'gains' from the high Arctic?).

The SW quad of Beaufort looks awful as does the ESS/Laptev/Kara so how will those areas look come Aug?

Then we have the heat in the Ocean ( like that in Bering entering the basin) to think on? If storms do spin the ice out to peripheral areas this might also take ice that would once have struggled trough the season?

I think this past 5 years, though looking good for the ice, have masked other changes moving us closer to a time where an 'average summer' will be enough to see us practically ice free. Winter will play its role in this 'preconditioning'.

So , back to the ice!
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FishOutofWater

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Re: The 2018 melting season
« Reply #1875 on: July 02, 2018, 02:08:48 PM »
If a cyclone is "hot core" at 250mb, and it's not a tropical cyclone, that means that the sounding is from the stratosphere.

The latest ECMWF run gets very stormy in the central Arctic. If it verifies there will be melting on the Eurasian side but the American side of the Arctic will be cold. This would be very good for ice preservation in the central Arctic as a whole. This model run would kill "melting momentum" in much of the Arctic.

Pagophilus

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Re: The 2018 melting season
« Reply #1876 on: July 02, 2018, 02:28:35 PM »
Hi Aluminium.  Your point is taken re. the limited area of the inner Laptev Sea and the New Siberian Islands... some high temperatures and very likely some rain are inbound.  This is likely to impact the ice in that local area.  However, there can be a tendency in some quarters to regard each incoming storm as the end of the Arctic as we know it.  Experienced members of this forum have warned us that cyclones in June and July are generally regarded as slowing, not speeding ice loss. 

So I did some rough checking on nullschool.  I took a random point in the outer Laptev Sea for tomorrow, when the first cyclone is at its height (and about 36 hrs from the time of your post).  I took surface winds and temperature as it is these that affect the ice.  Please see images below. Surface temps at this point are predicted by the model to be around 1 C, winds around 30 kph, precipitable water around 10 kg/m^2. 

Clicking around this point (out in the Arctic, not next to the shore), surface temps range around 0.2 to 3 C, winds up to 45 kph, precipitable water up to 20 kg/m^2.  The cyclone fades past this day.  Moving to the July 5 prediction, the situation was about the same.  The evidence from this indicates to me that the impact of the storm is likely to be mostly local to the region of and adjacent to the New Siberian Islands.  However, the cloudiness brought about by this weather is likely to reduce insolation over a wide area, and it is highly possible that this will result in a net slowing of the loss of Arctic ice. 

So, yes, I think this movie will be much like the June cyclone version, with maybe a fresh subplot featuring a torrid scene around the NSI.

 
I think I saw a version of this movie last month -- the one featuring the June cyclone.   ;)
Yes. However total precipitable water did not surpass 30 kg/m2 above the Arctic Ocean at that time. This heat intrusion will begin in 36 hours. Temperature at 850 hPa will exceed 15°C (up to 19°C) around the New Siberian Islands. Elsewhere this is enough for 30-35°C near surface.

Pagophilus

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Re: The 2018 melting season
« Reply #1877 on: July 02, 2018, 03:40:50 PM »
Hyperion, re your statement "most of the energy is inbound at high velocity and humidity at high altitude".   Virtually all weather systems can have much higher velocity winds at higher altitudes.  Many also have high relative humidities at higher altitudes.  The 500 and 250 hPa pressures you chose for your sampling correspond to altitudes of around 5000 m and 10000 m.

Neither of these measures (wind speed, rel. humidity) mean much in energy terms because air is at such low density at 500 hPa and 250 hPa, and that air is bloody freezing (ca -20 C to -40 C).   Water vapor content is likely to be miniscule in these conditions and so relative humidity (in energy content terms) means almost nothing.  So choosing this information and writing that "most of the energy is inbound at high velocity and humidity at high altitude" seems wildly incorrect to me.

BTW:  What high relative humidity at high altitude might mean is that clouds are more likely to be present, maybe as ice crystals, which may mean benefit Arctic ice retention.  As to hot core vs. cold core at different altitudes, I have no expertise there, but I think Fish addresses that.

As ever, I am happy to be corrected by experts and to learn (there may be stuff I don't know, like dynamic interactions in the atmosphere) but my instincts of common sense urged me on here. 

 
Very interesting weather system. Most of the energy is inbound at high velocity and humidity at high altitude. The cyclone is hot core at 250hPa, but cold core below.
« Last Edit: July 02, 2018, 04:09:51 PM by Pagophilus »

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Re: The 2018 melting season
« Reply #1878 on: July 02, 2018, 07:38:15 PM »
This morning's ECMWF forecast has the cyclone at 975 hPa now, starting the day after tomorrow, which then de-intensifies and slowly moves towards the Beaufort, all the while surrounded by high pressure. If the high pressure above the Kara Sea comes about, it's a new region that receives a solar blast.

That looks like at least two days of winds from the south blowing directly over the big thick blob of ice in the southern ESS...

Aluminium

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Re: The 2018 melting season
« Reply #1879 on: July 02, 2018, 07:44:31 PM »
So I did some rough checking on nullschool.  I took a random point in the outer Laptev Sea for tomorrow, when the first cyclone is at its height (and about 36 hrs from the time of your post).  I took surface winds and temperature as it is these that affect the ice.  Please see images below. Surface temps at this point are predicted by the model to be around 1 C, winds around 30 kph, precipitable water around 10 kg/m^2.
Hi Pagophilus. As for 36 hours from my post, I meant that hot air at 850 hPa will have arrived to Lena delta only (first image). Second and third images contain the forecast for 60 and 84 hours from my post. Also there will be a large cloudless area (last image).

Pagophilus

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Re: The 2018 melting season
« Reply #1880 on: July 02, 2018, 07:54:12 PM »
Got it.  Thanks, Aluminium.
So I did some rough checking on nullschool.  I took a random point in the outer Laptev Sea for tomorrow, when the first cyclone is at its height (and about 36 hrs from the time of your post).  I took surface winds and temperature as it is these that affect the ice.  Please see images below. Surface temps at this point are predicted by the model to be around 1 C, winds around 30 kph, precipitable water around 10 kg/m^2.
Hi Pagophilus. As for 36 hours from my post, I meant that hot air at 850 hPa will have arrived to Lena delta only (first image). Second and third images contain the forecast for 60 and 84 hours from my post. Also there will be a large cloudless area (last image).

A-Team

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Re: The 2018 melting season
« Reply #1881 on: July 02, 2018, 08:19:37 PM »
Folks, all these D5 weather forecasts need to be revisited at day 5 as a second post to determine if they indeed had the anticipated effects on the ice (meaning an observable change in one of the direct satellite products we commonly use). Otherwise it is just a lot of hot air and rapidly depreciating hectares of forum space.

We can monitor Arctic ice change without the weather forecasts but change without attribution doesn't move our understanding forward. The weak link is not forecast accuracy but rather coupling to the ice.

This close to the solstice, insolation is putting vastly more heat into and under the ice than low conductivity air. Clouds can mitigate insolation or make it far worse for the ice, Hyperion @ #1517 posted a rare in-depth discussion of the issues there. We've been at this far too long to still be saying 'low pressure bring clouds bring low melt'.

ESRL provides daily net energy flow maps and forecasts that have never drawn interest here. These have a model component to be sure but are have to be better than just intuiting radiative transfer.

Winds are very important to floe dispersion and hence to melt. We started looking at this cyclone situation back on June 30th (mp4 repeated below, units are wind power density), with predicted unravelling of the (exclusively Kara Tongue) ice edge and interior north of Svalbard-FJL. That seems to be gathering steam on July 1st as expected, with several more days of the same likely to follow. Here Sentinel-1AB and UH AMSR2 are used as the before and after monitoring tools as Ascat and Jaxa products are largely featureless in this region.

Jaxa is back in business! The muddy grays there do a good job at defining at-risk ice. We are seeing very rapid disintegration of sea ice concentration in the central Beaufort as well as south Kara in addition to late-stage melt on the Siberian side and inside the CAA.

Technical note: the non-contiguous color picker in gimp or photoshop though not imageJ can exploit the color complexity of Jaxa RGB. Below the fiducial gray was examined at multiple sites using the averaging capability of the picker, radius 15 and the HSV/RGB foreground value readout. The picker radius was set at 12 in the color cube after some experimentation, the selection grown 1 pxl to pick up strays, edited with the loop tool to remove land artifacts, then filled with a dimmed line pattern and flattened. The boundaries of the at-risk area are too complex to pick manually, especially for the time series necessary to mitigate passing weather artifacts.

To convey wind speeds more effectively, short bursts of nullschool (resp. windy) are captured at 3 hr intervals for five days and concatenated to a mp4 in a semi-automated manner, as described over at Dev Corner. After prediction expiry, the winds can be revisited by backing up nullschool to the required range


Quote
H's post, minor edits: 'The situation with clouds and inbound/outbound energy fluxes is far more complicated than what you can tell by eyeballing visible and infrared Worldview imagery. Seeing cloud cover across most of the Arctic basin in true color Terra, 3-6-7 Terra, andBand 15 VIIRS cannot be interpreted as favorable to ice retention. There is only a narrow range of very small liquid water droplet cloud at that has a beneficial effect on radiation fluxes and it must be at least a kilometer up to not be subject to wind waves that are rolling it down on the ice surface.

Ice crystal clouds are unfavorable as they let in most of the high energy part of the spectrum but blocks outgoing long wave radiation. It may feel cooler to you under ice crystal cloud than a clear sky but you will sunburn just as fast. And bottom melting is likely to be enhanced. Low-level large water droplet cloud like fog or anything even a little gray, also blocks outgoing long wave, and very efficiently absorbs all incoming solar spectra but for a few narrow bands of visible spectrum.

If there is any air movement then the droplets and worse liberated vapor transfer the energy to the ice. And the absorbed spectra are re-radiated as long wave radiation, half of which get down to the surface anyway. So if it is below freezing at 850 hPa, there is no cloud cover beneficial to ice, ditto any significant air movement near surface ditto. Comparing total atmospheric column cloud water with total precipitable water shows there is far more water as vapor than cloud these days over the Arctic.

Whether directly on the ice or at altitude where the long wave can deeply penetrate the ice, this is very bad for ice as the latent heat when it condenses and later freezes is enormous.  You may not feel the heat of being cooked by microwaves but you are. And you may feel cold in humid or foggy conditions when the air temp is low (but above freezing) but you are warmer, the ice is colder, so it feels warm.'
« Last Edit: July 03, 2018, 02:46:40 AM by A-Team »

Lord M Vader

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Re: The 2018 melting season
« Reply #1882 on: July 02, 2018, 08:37:36 PM »
EC operational 12z run is crazy! D5-D6 has an intensive cyclone at 966-967 hpa for more than 24 hours(!) If this model run verifies I would like to classfy this as a GAC. Is that OK with you, Neven? ;)
 
Adding to that a very strong reversed dipole that should put the thickest ice closer to the Pacific death zone while thinner ice close to Svalbard will be pushed closer to the North Pole. See apersons post #1855 that shows HYCOMs estimation of the sea ice thickness for the years 2014-2018

Ken Feldman

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Re: The 2018 melting season
« Reply #1883 on: July 02, 2018, 08:42:33 PM »
If a cyclone is "hot core" at 250mb, and it's not a tropical cyclone, that means that the sounding is from the stratosphere.

The latest ECMWF run gets very stormy in the central Arctic. If it verifies there will be melting on the Eurasian side but the American side of the Arctic will be cold. This would be very good for ice preservation in the central Arctic as a whole. This model run would kill "melting momentum" in much of the Arctic.

Arctic cyclones differ from tropical cyclones in many ways, including how they're formed.  It's typical for an Arctic cyclone to develop from a warm front over land meeting a cold front over the Arctic ocean ice edge.  Here's a good article about the structure of Arctic cyclones:

https://www.sciencedirect.com/science/article/pii/S1873965212000072

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It is found by the analysis of this study that the arctic cyclone indicates many differences in structure and behavior compared with the mid-latitude cyclone. The arctic cyclones move rather randomly in direction over the Arctic Ocean. The arctic cyclone has a barotropic structure in the vertical from the surface to the stratosphere. The arctic cyclone detected at the sea level pressure is connected with the polar vortex at the 500 hPa level and above. Importantly, the arctic cyclone has a cold core in the troposphere and a warm core around the 200 hPa level.


Thawing Thunder

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Re: The 2018 melting season
« Reply #1884 on: July 03, 2018, 12:16:35 AM »
Jaxa is back in business! The muddy grays there do a good job on defining at-risk ice. We are seeing very rapid disintegration of sea ice concentration in the central Beaufort as well as south Kara in addition to late-stage melt on the Siberian side and inside the CAA.

I wasted my predictive poof potential over the last two or three years, so I'll stay quiet on this one but I must admit that it looks very intriguing.
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Alexander555

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Re: The 2018 melting season
« Reply #1885 on: July 03, 2018, 01:13:29 AM »
If these pics are right, than everything is possible. There was more ice in the Kara Sea and in the Beaufort Sea in 2017. But this year all the thick ice is gone. The central part is like a meter thinner.

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Re: The 2018 melting season
« Reply #1886 on: July 03, 2018, 03:18:39 AM »
If these pics are right, than everything is possible. There was more ice in the Kara Sea and in the Beaufort Sea in 2017. But this year all the thick ice is gone. The central part is like a meter thinner.
The 7/2/2018 model has a lot in common with the last graphic in A-Team's #1881 post.

I'd also say, a half meter rather than a full one.
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GoSouthYoungins

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Re: The 2018 melting season
« Reply #1887 on: July 03, 2018, 05:45:33 AM »
I suggest (maybe for next season), two concurrent season threads. Thread A: only matter of fact observations and forecast based on well established patterns (maybe how this forum used to be).  Thread B, anything fairly relevant (how the 2018 melting thread is). Everything from thread A should be posted to thread B, but certainly not the other way around.
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Re: The 2018 melting season
« Reply #1888 on: July 03, 2018, 05:54:53 AM »
The Chaunskaya Bay rapidly melted out over the past week. Now that the ice is gone, one of the main culprits is more clear: An algae bloom
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Re: The 2018 melting season
« Reply #1889 on: July 03, 2018, 06:25:33 AM »
Heat plume en route / fires burning brightly. EOSDIS coming in smoky but Himawari shows the plumes. Very neat.

There is also a typhoon in the Sea of Japan. That is apparently the source of the impending GAC on modeling. The +500MB ridging overhead (enhanced further by its own latent heat release) should fuel a worsening of the fires through D3.

Comparing imagery, this is occurring much closer to the sea ice than where fires were at the same time in 2012.

https://himawari8.nict.go.jp/
« Last Edit: July 03, 2018, 06:31:07 AM by bbr2314 »

cesium62

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Re: The 2018 melting season
« Reply #1890 on: July 03, 2018, 06:58:34 AM »
Thread A: only matter of fact observations and forecast based on well established patterns (maybe how this forum used to be).
You and I have been reading two different forums for the past few years.   ;D

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Re: The 2018 melting season
« Reply #1891 on: July 03, 2018, 07:55:19 AM »
One thing is for sure.

I can't recall a blast of heat ever this intense actually exploding over an area of arctic ice as large as this one is expected to encompass.

The models are showing very strong well mixed winds vertically stacked over a long fetch for 36-60 hours over parts of the Pacific side. 

This is going to bring a period of 2-4C surface temps over the ESS, chuchki, and Beaufort.

With even warmer surface temps of 4c+ grazing the edges.

This will allow tremendous heat to reach the ice surface.  Pending clouds and rain.  Melt rates are going to jump into the 5-10cm/day range.

And expect huge drops in extent and area because the entire ESS shoreline is going to see open water explode into existence.  We will see likely 30-40km a day of ice cleared off the shoreline.

Models show no local inversions at the surface..

meaning the 20-35C air coming off the shoreline will directly cream the ice front bringing a steady supply of heat smoking the near shore ess ice.

Also where open water appears ssts will immediately jump to explosive warmth for the ESS.

LIKE 5C+ easily against the ice sheet.

Lasting impacts remain to be seen but this is going to be epic
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Neven

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Re: The 2018 melting season
« Reply #1892 on: July 03, 2018, 08:26:35 AM »
EC operational 12z run is crazy! D5-D6 has an intensive cyclone at 966-967 hpa for more than 24 hours(!) If this model run verifies I would like to classfy this as a GAC. Is that OK with you, Neven? ;)

I'm the dictator of this Forum, but not of GAC definitions.  ;)

However, here's my opinion: It's D5-D6, but if it does go below 970 hPa, the storm may apply for GAC-status. But as I said, there are a couple of parameters. There was a good paper on GAC-2012 discussing these things, but I don't believe there's a fixed set of parameters. I'll see if I can find it again (I discussed it on the ASIB when the 'GAC'-2016 hit).
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Re: The 2018 melting season
« Reply #1893 on: July 03, 2018, 08:40:40 AM »
Quote
So choosing this information and writing that "most of the energy is inbound at high velocity and humidity at high altitude" seems wildly incorrect to me.
It

Pagophilus OK chum. There are only four attachments allowed per post here. The winds were in the region of 100kmph and carrying 100% humidity from 850 hpa or about 1.5 km altitude right up to the stratosphere with the high humidity areas at 500 and 250 closest matches for the dense tpw stream.  I was in a hurry,  so did not have time to gif the whole humidity altitude range for your pleasure. If you looked for yourself you would have seen that at surface and 1000hpa the winds were cooler, much slower and less humid. Check for me please what percentage of the atmospheres weight is above say 1km? And please don't accuse me of being misleading until you have calculated its energy flux coming in at 3 times the speed of the low altitude winds.
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Alexander555

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Re: The 2018 melting season
« Reply #1894 on: July 03, 2018, 09:00:22 AM »
If these pics are right, than everything is possible. There was more ice in the Kara Sea and in the Beaufort Sea in 2017. But this year all the thick ice is gone. The central part is like a meter thinner.
The 7/2/2018 model has a lot in common with the last graphic in A-Team's #1881 post.

I'd also say, a half meter rather than a full one.

That's probably closer to it. It makes me think about the volume pics we see here sometimes. They all have more volume compared to this year. But most models have more thick ice in it, compared to the 2 pics above. And with area still pretty big i think we are going to see big volume drops in the next weeks.

Aluminium

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Re: The 2018 melting season
« Reply #1895 on: July 03, 2018, 09:18:06 AM »
June 28 - July 2.

oren

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Re: The 2018 melting season
« Reply #1896 on: July 03, 2018, 09:30:05 AM »
June 28 - July 2.
The "race to the CAB" is on with strong advances in the Chukchi, Beaufort, Laptev, and off-Kara, with some of the lost ice actually being exported to the north of Svalbard (off-Barents) limiting extent losses.
The CAA seems to be losing some of its melt ponds, probably to drainage.

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Re: The 2018 melting season
« Reply #1897 on: July 03, 2018, 12:36:56 PM »
Mackenzie bay yesterday jul2. Relatively clear skies over the open water and ice in the center of the image allow a look at the surface temperatures using VIIRS band15.
Light blue ~-2C
Yellow       ~12C

edit: red ~6C
« Last Edit: July 03, 2018, 01:15:10 PM by uniquorn »

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Re: The 2018 melting season
« Reply #1898 on: July 03, 2018, 01:00:29 PM »
I suggest (maybe for next season), two concurrent season threads. Thread A: only matter of fact observations and forecast based on well established patterns (maybe how this forum used to be).  Thread B, anything fairly relevant (how the 2018 melting thread is). Everything from thread A should be posted to thread B, but certainly not the other way around.

i think such a thread exists already:

https://forum.arctic-sea-ice.net/index.php/topic,2274.0.html

uniquorn

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Re: The 2018 melting season
« Reply #1899 on: July 03, 2018, 01:06:36 PM »
Laptev gap today, jul3, with the same palette.
Light blue ~-2C
Purple       ~4C

some cloud in centre left of image and what looks like a different swath on bottom left