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Neven

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Re: The 2016 melting season
« Reply #4050 on: August 17, 2016, 01:41:56 AM »
I've been busy all evening writing the first 2016 Arctic cyclone update. I'm not surprised to see that the same is being discussed here.   :)
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JayW

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Re: The 2016 melting season
« Reply #4051 on: August 17, 2016, 01:57:12 AM »
"To defy the laws of tradition, is a crusade only of the brave" - Les Claypool

Ninebelowzero

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Re: The 2016 melting season
« Reply #4052 on: August 17, 2016, 02:13:40 AM »
I've been busy all evening writing the first 2016 Arctic cyclone update. I'm not surprised to see that the same is being discussed here.   :)

Forum Melt Season fatigue syndrome has set in. 8)

Juan C. García

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Re: The 2016 melting season
« Reply #4053 on: August 17, 2016, 03:27:47 AM »
I've been busy all evening writing the first 2016 Arctic cyclone update. I'm not surprised to see that the same is being discussed here.   :)

Anxiously awaiting for the probable drop of the SIE. Two hours to recieve the new ADS data?
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

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

Juan C. García

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Re: The 2016 melting season
« Reply #4054 on: August 17, 2016, 04:36:13 AM »
I do not like the Bremen graphs. Seems to me that they always end with an uptick (less melt than there should be). On the other hand, I always look the ASI picture. Looking at it, I will just say an opinion: I see less area and extent...
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

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

CraigsIsland

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Re: The 2016 melting season
« Reply #4055 on: August 17, 2016, 06:43:01 AM »
Now I'm curious if GAC 2016 will impact melt rates around Greenland.  Was there an analog for GAC 2012 that could be applied to Greenland?

Intense positive feedbacks for sure. Just Amazing to see it unfold.

epiphyte

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Re: The 2016 melting season
« Reply #4056 on: August 17, 2016, 07:10:56 AM »
I do not like the Bremen graphs. Seems to me that they always end with an uptick (less melt than there should be). On the other hand, I always look the ASI picture. Looking at it, I will just say an opinion: I see less area and extent...

I know it's just hand-waving, but I tend to assume that when there appears to be new ice in the direction the wind is blowing, and the ice that was upwind of it yesterday still looks the same, and EOSDIS shows heavy cloud cover over that same area (which it will if it is now open water which is warmer than the air above it), then some of the ice is being counted twice...

seaicesailor

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Re: The 2016 melting season
« Reply #4057 on: August 17, 2016, 07:17:09 AM »
It looks like the flow through from the Pacific through the Bering strait to the Atlantic has been minimal for months. In 2007 & 2012 there was more warm water from the Pacific to melt out the ice...
Are there numbers of this being published near real-time? I have been looking around with no success.
I have been observing what could be effects of Pacific inflow this year, but can't compare it to 2007 and 2012 without numbers.

epiphyte

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Re: The 2016 melting season
« Reply #4058 on: August 17, 2016, 07:21:44 AM »
I've been busy all evening writing the first 2016 Arctic cyclone update. I'm not surprised to see that the same is being discussed here.   :)

I was going to comment on ASIB about that - but as a conscientious objector to facebook et. al. this will have to do :) ...

 - if the 192H ECMWF forecast turns out right, perhaps we should call it "The Great White Spot"?



Geoff

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Re: The 2016 melting season
« Reply #4059 on: August 17, 2016, 09:25:29 AM »
Just wondering about cyclones:

They usually form over the sea and dissipate once they make landfall, right? I assume in previous years these cyclones were not as devastating or long lasting to the more solid Arctic ice. And with there being less solid ice to act as a dampener, they are less likely to expire as quickly?

Is it possible that in 10/15 years, once most of the remaining ice is gone, these cyclones will be a more or less permanent fixture over the summer months?

Thawing Thunder

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Re: The 2016 melting season
« Reply #4060 on: August 17, 2016, 09:28:36 AM »
- if the 192H ECMWF forecast turns out right, perhaps we should call it "The Great White Spot"?

The strange cloud formations at the poles of Saturn also come to mind. But while those eye-like and hexagonal structures are associated with satanic evil, the Earth's Arctic ice this year could assume the shape of a heart :o.
« Last Edit: August 17, 2016, 10:02:57 AM by Thawing Thunder »
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JayW

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Re: The 2016 melting season
« Reply #4061 on: August 17, 2016, 11:32:38 AM »
The models looks relentless, and in relative agreement.

http://mp1.met.psu.edu/~fxg1/CMCNA_0z/hgtcomp.html

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iceman

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Re: The 2016 melting season
« Reply #4062 on: August 17, 2016, 03:21:44 PM »
Just wondering about cyclones:
   ....
(quoting from other thread)
   ....  The research on the 2012 GAC states that an upper level vortex is key to the generation and longevity of major Arctic cyclones.  Looking at 250hp winds there has been a strong vortex in play, and has been for a while.  However whether the low pressure generated this upper vortex, or the upper generated the surface low I'm not sure.  Looking at the CMC forecast (only model I found with 250hp winds for Arctic) what stands out to me is that the jetstream through the European and west Russian region is quite weak, and a lot of the jetstream wind is diverted into a branch that passes through the Barents/Kara/Laptev sea region.  My guess is that this diversion may be playing a key role in what is predicted to be the rapid development of a low pressure system over that general region.  ....
This sounds like a good insight.  Lower-level winds are picking up considerable warmth and moisture from Barents and Kara, which seems to contribute to the re-intensification of the central low.

    Sun 2100 UTC Aug 21 as of 20160817

seaicesailor

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Re: The 2016 melting season
« Reply #4063 on: August 17, 2016, 04:20:10 PM »
ECMWF forecast for Saturday predicts the storm down to 974 hPa with the center close to CAA. The ECMWF ensemble pretty much agrees on the general pattern. The question is what consequences this pattern has for extent.

12Patrick

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Re: The 2016 melting season
« Reply #4064 on: August 17, 2016, 05:48:33 PM »
NE coast of Greenland ice is gone now. Been watching this area for 30 years and it used to be 5 meters thick all along the coast up there. This year it is gone.. https://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictnnowcast.gif

Lord M Vader

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Re: The 2016 melting season
« Reply #4065 on: August 17, 2016, 06:22:02 PM »
Extended crossposting from "What the bouys are telling" but important info so...

NEVEN & Co: According to Brian Brettschneider via Twitter, a bouy close to the storm center measured a MSLP at 966,5 hpa during this GAC. See the tweet at: https://twitter.com/Climatologist49/status/765599419999760384

Best, LMV

budmantis

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Re: The 2016 melting season
« Reply #4066 on: August 17, 2016, 06:52:24 PM »
NE coast of Greenland ice is gone now. Been watching this area for 30 years and it used to be 5 meters thick all along the coast up there. This year it is gone.. https://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictnnowcast.gif

Not according to Modis, there's an area offshore that remains, it is under some clouds but still appears to be there.

I'm not very good at posting pictures, perhaps someone else can make it stand out more.

Tigertown

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Re: The 2016 melting season
« Reply #4067 on: August 17, 2016, 07:02:29 PM »
What the cloud cover has been hiding.


jdallen

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Re: The 2016 melting season
« Reply #4068 on: August 17, 2016, 07:35:07 PM »
NE coast of Greenland ice is gone now. Been watching this area for 30 years and it used to be 5 meters thick all along the coast up there. This year it is gone.. https://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictnnowcast.gif

Not according to Modis, there's an area offshore that remains, it is under some clouds but still appears to be there.

I'm not very good at posting pictures, perhaps someone else can make it stand out more.
Point taken, but semantics, I think budmantis.  I'd guess what you see there is 10% of what it used to be, and even that is probably thinner.
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Nightvid Cole

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Re: The 2016 melting season
« Reply #4069 on: August 17, 2016, 07:48:07 PM »
Seems the cyclone is doing a number on the ice:


Lord M Vader

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Re: The 2016 melting season
« Reply #4070 on: August 17, 2016, 07:54:49 PM »
Latest 12z op GFS calls for another "bomb cyclone" of sigmilar strength bottoming out at 971 hpa in 150 hours. Also seems like that one might put some warm air advection into the Arctic basin, something that the recent cyclone didn't.

The ECMWF 00z  run also had a bomb cyclone but later in the forecast period.

If one intensive cyclone is bad for the ice, how about two then or perhaps even three?

966,5 hpa for the latest cycone isn't to bad. GAC-2012 had about 963-964  hpa as lowest :)

Neven

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Re: The 2016 melting season
« Reply #4071 on: August 17, 2016, 08:57:26 PM »
Thanks for the link, LMV (I'll use it in the next update). 966.5 hPa is practically on a par with GAC-2012, although my subjective impression is that GAC-2012 weakened slower than this one. On the other hand, this one may re-intensify.

This is pretty exciting!
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AbruptSLR

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Re: The 2016 melting season
« Reply #4072 on: August 17, 2016, 09:20:43 PM »
ECMWF forecast for Saturday predicts the storm down to 974 hPa with the center close to CAA.

The attached ECMWF run has it down to 973 hPa for August 20 2016
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seaicesailor

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Re: The 2016 melting season
« Reply #4073 on: August 17, 2016, 09:30:06 PM »
This cyclone went below 970 hPa, then down to 968 hPa and then up to 980 hPa in 60 hours following the canadian charts. This is longer than what the buoy shows, the buoy of course was not following the center. But still one day 12h less or so than GAC-2012 (if I got it right not so much difference)
This one is going down to ~970 hPa in 48h - 72h (thx ASLR) and then maybe again, while the GAC had petered out by that time. With which consequences, we'll see...
Blue curve shows central pressure GAC 2012 from
http://onlinelibrary.wiley.com/doi/10.1029/2012GL054259/full
« Last Edit: August 17, 2016, 09:36:29 PM by seaicesailor »

AbruptSLR

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Re: The 2016 melting season
« Reply #4074 on: August 17, 2016, 09:42:30 PM »
This cyclone went below 970 hPa, then down to 968 hPa and then up to 980 hPa in 60 hours following the canadian charts. This is longer than what the buoy shows, the buoy of course was not following the center. But still one day 12h less or so than GAC-2012 (if I got it right not so much difference)
This one is going down to ~970 hPa in 48h - 72h (thx ASLR) and then maybe again, while the GAC had petered out by that time. With which consequences, we'll see...

For ease of reference here is the buoy's barometric pressure readings that LMV linked to for August 15-16, 2016:
“It is not the strongest or the most intelligent who will survive but those who can best manage change.”
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budmantis

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Re: The 2016 melting season
« Reply #4075 on: August 17, 2016, 10:00:56 PM »
NE coast of Greenland ice is gone now. Been watching this area for 30 years and it used to be 5 meters thick all along the coast up there. This year it is gone.. https://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictnnowcast.gif

Not according to Modis, there's an area offshore that remains, it is under some clouds but still appears to be there.

I'm not very good at posting pictures, perhaps someone else can make it stand out more.
Point taken, but semantics, I think budmantis.  I'd guess what you see there is 10% of what it used to be, and even that is probably thinner.

Your point is taken as well JD, but the question is; Is there ice remaining or not? I agree that what remains is a small fraction of what was there.
« Last Edit: August 18, 2016, 12:25:33 AM by budmantis »

Michael Hauber

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Re: The 2016 melting season
« Reply #4076 on: August 18, 2016, 06:06:55 AM »
GFS model suggests temps at 850hp have dropped below -8 for much of the remaining ice pack.  Andrew Slater's 925hp temps have dropped a good way below 0, although not quite as far as I thought they might go.  Is the surface melt season all but over now?  And perhaps an early end to the bottom melt season later on?
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bbr2314

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Re: The 2016 melting season
« Reply #4077 on: August 18, 2016, 07:21:49 AM »
Getting closer..



And don't forget another near-GAC at D2


budmantis

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Re: The 2016 melting season
« Reply #4078 on: August 18, 2016, 07:39:06 AM »
Impressive. Welcome back BBR!

jdallen

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Re: The 2016 melting season
« Reply #4079 on: August 18, 2016, 08:12:08 AM »
GFS model suggests temps at 850hp have dropped below -8 for much of the remaining ice pack.  Andrew Slater's 925hp temps have dropped a good way below 0, although not quite as far as I thought they might go.  Is the surface melt season all but over now?  And perhaps an early end to the bottom melt season later on?
Until we get to -10C and below, I expect bottom melt will continue as long as we have weather stirring up the pack.  That will continue the process of retrieving heat from depth to replenish that lost to re-radiation.  With as much heat as has entered the basin and peripheral seas, I expect we may continue losing extent and area through the end of September.
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seaicesailor

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Re: The 2016 melting season
« Reply #4080 on: August 18, 2016, 09:02:22 AM »
GFS model suggests temps at 850hp have dropped below -8 for much of the remaining ice pack.  Andrew Slater's 925hp temps have dropped a good way below 0, although not quite as far as I thought they might go.  Is the surface melt season all but over now?  And perhaps an early end to the bottom melt season later on?
Until we get to -10C and below, I expect bottom melt will continue as long as we have weather stirring up the pack.  That will continue the process of retrieving heat from depth to replenish that lost to re-radiation.  With as much heat as has entered the basin and peripheral seas, I expect we may continue losing extent and area through the end of September.
I think so too. Even with the current drop if something should keep up bottom melt is current weather. The question is what happens with atmospheric temps when all these gales end, anything I guess.


Andreas T

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Re: The 2016 melting season
« Reply #4081 on: August 18, 2016, 09:05:52 AM »
To illustrate what JD said I am attaching the graph from IMB2015F focussing on last autumn. Dropping air temperature does not stop bottom melt, but melt rates in September are much lower than in August. Snow cover actually helps by reducing exposure of the ice to the cold air.
Observations (anectotal, I know) from recent days show raised temperatures (just below zero) at Obuoy14 as winds have picked up and Northbound reporting warm air blowing from the Siberian mainland onto coastal water.
I am no meteorologist, how, with air rising and cooling in the low, do these 850hpa temperatures impact the ice below? Or are they an indication of, rather than an impact on, the conditions below?
Cloud now shelters the ice from radiation losses, when the gains from incoming solar radiation are becoming small, trading lower gains for lower losses can be an advantage.
How much water is cooled by evaporation I don't know but it will depend on humidity of the air so where air has blown over large stretches of warmer water its cooling effect at the ice edge could be small.

slow wing

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Re: The 2016 melting season
« Reply #4082 on: August 18, 2016, 10:30:18 AM »
Nice display pictured below of how the ice pack has been spinning around over the past 48 hours - something it is forecast to do a lot more of this month.

The source is http://osisaf.met.no/p/osisaf_hlprod_qlook.php?prod=LR-Drift-demo&area=NH.

I would say the divergence of the ice pack can also be seen. That is the Coriolis effect: the ice is spinning anti-clockwise, which is the same sense as the Earth's rotation as seen looking down on the North Pole, and so is also flying outwards.

NeilT

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Re: The 2016 melting season
« Reply #4083 on: August 18, 2016, 11:02:48 AM »
GFS model suggests temps at 850hp have dropped below -8 for much of the remaining ice pack.  Andrew Slater's 925hp temps have dropped a good way below 0, although not quite as far as I thought they might go.  Is the surface melt season all but over now?  And perhaps an early end to the bottom melt season later on?
Until we get to -10C and below, I expect bottom melt will continue as long as we have weather stirring up the pack.  That will continue the process of retrieving heat from depth to replenish that lost to re-radiation.  With as much heat as has entered the basin and peripheral seas, I expect we may continue losing extent and area through the end of September.
I think so too. Even with the current drop if something should keep up bottom melt is current weather. The question is what happens with atmospheric temps when all these gales end, anything I guess.

I wrote my final "guess" about the 2016 melt season on the blog rather than the forum.  But to repeat.  If it follows 2006 as I have said all along, there will be an increasing melt season in August (I said that already), followed by a sharp stop and some re-growth at the end of the first week in September, but with bottom melt into the third week in September.

That, for me, will be the final observation.  Well apart from all that heat derailing the onset of the winter ice pack and leaving it both weak and thin for the next season's melt.

For anyone who watches Hurricanes quite closely (not at a meteorological level but more where they go and what it does to SST), it's clear that hurricanes work on the differential between excessive SST's and the colder atmosphere above.  Hurricanes suck the heat out of the sea and, in parallel, give it to the upper atmosphere and sequester it in water vapour which is both cooled and delivered to another location (often land), in the form of torrential downpours.

That is what I'm seeing here. The deeper the pressure gradient, the more heat is being sucked out of the sea to be transported elsewhere.  That, I believe, whilst having a short term effect of pumping heat from the depths right now, will end the bottom melt earlier than would otherwise have been the case.  Without the storms we should see bottom melt into October.

Storms or no storms we can see that areas of ice (ESS for instance), are simply not melting the way they did in 2012.

If I'm correct and top melt ends less than 3 weeks from today, we'll have a 3rd/4th place finish in extent with, as I've said all along, something quite interesting in the area stakes.  I believe effective open water pretty much to the pole classifies as "interesting" and that's what it's looking like now.

That falls into the same category as the open lead of September 2006 where the excessive SST's continued to do their damage under the ice even after the top melt had ended.

I'm already looking forward to the winter growth season and next years melt season.  2016 may have some surprises yet, but my anticipation is all for the next 14 months.
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Michael Hauber

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Re: The 2016 melting season
« Reply #4084 on: August 18, 2016, 11:21:05 AM »
To illustrate what JD said I am attaching the graph from IMB2015F focussing on last autumn. Dropping air temperature does not stop bottom melt, but melt rates in September are much lower than in August. Snow cover actually helps by reducing exposure of the ice to the cold air.
Observations (anectotal, I know) from recent days show raised temperatures (just below zero) at Obuoy14 as winds have picked up and Northbound reporting warm air blowing from the Siberian mainland onto coastal water.

The insulating effect of a meter of ice delays the end of bottom melt, and start of bottom freeze significantly.  Freeze did not noticeably start until November at that location, whereas new ice is definitely forming by late September. 

I am no meteorologist, how, with air rising and cooling in the low, do these 850hpa temperatures impact the ice below? Or are they an indication of, rather than an impact on, the conditions below?

850hp is going to mix with the surface quite well particularly in windy conditions.  Of course pressure differences mean that when air descends from 850hp to the surface it is going to warm up by something like 10 degrees.  I think it is less when the air is saturated though.  Also while tropical depressions may be characterised by rising air, mid-lattitude lows are more complicated with areas of both rising and sinking air, with most of the rising air in a wedge between the warm and cold fronts.  This sector is most significant in the developing phase of the low, and once it peaks as it has now much of this activity is occluded by colder more stable air on the surface and unstable rising air pushed higher above the surface.  As far as I know most Arctic cyclones have the same structure.
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BornFromTheVoid

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Re: The 2016 melting season
« Reply #4085 on: August 18, 2016, 11:34:35 AM »
A pretty cool new visualisation tool, like nullschool.
https://www.windyty.com/

Kate

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Re: The 2016 melting season
« Reply #4086 on: August 18, 2016, 12:11:24 PM »
GFS model suggests temps at 850hp have dropped below -8 for much of the remaining ice pack.  Andrew Slater's 925hp temps have dropped a good way below 0, although not quite as far as I thought they might go.  Is the surface melt season all but over now?  And perhaps an early end to the bottom melt season later on?
Until we get to -10C and below, I expect bottom melt will continue as long as we have weather stirring up the pack.  That will continue the process of retrieving heat from depth to replenish that lost to re-radiation.  With as much heat as has entered the basin and peripheral seas, I expect we may continue losing extent and area through the end of September.
I think so too. Even with the current drop if something should keep up bottom melt is current weather. The question is what happens with atmospheric temps when all these gales end, anything I guess.

For anyone who watches Hurricanes quite closely (not at a meteorological level but more where they go and what it does to SST)...

That is what I'm seeing here. The deeper the pressure gradient, the more heat is being sucked out of the sea to be transported elsewhere.  That, I believe, whilst having a short term effect of pumping heat from the depths right now, will end the bottom melt earlier than would otherwise have been the case.  Without the storms we should see bottom melt into October.

Storms or no storms we can see that areas of ice (ESS for instance), are simply not melting the way they did in 2012.

If I'm correct and top melt ends less than 3 weeks from today, we'll have a 3rd/4th place finish in extent with, as I've said all along, something quite interesting in the area stakes.  I believe effective open water pretty much to the pole classifies as "interesting" and that's what it's looking like now.

That falls into the same category as the open lead of September 2006 where the excessive SST's continued to do their damage under the ice even after the top melt had ended.

I'm already looking forward to the winter growth season and next years melt season.  2016 may have some surprises yet, but my anticipation is all for the next 14 months.

Yes. Exactly what I was thinking ( but I am an amateur only ). ATM, lots of cyclonic activity around the pole. Lots of heat being drawn in with the jet stream

BornFromTheVoid

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Re: The 2016 melting season
« Reply #4087 on: August 18, 2016, 12:28:37 PM »
Just an animation of before and after the storm. The rotation in the pack is really noticeable for just 3 days.
Click to play

seaicesailor

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Re: The 2016 melting season
« Reply #4088 on: August 18, 2016, 12:58:24 PM »
1 degree of latitude, more in some points. That's 100 - 200 km.
Amazing he rotation is not felt in the Beaufort/Chukchi and Atlantic sectors. Amazing real melting rate.
However not so much in Laptev. Does Ekman pumping or other kinds of mixing/transport make heat and salinity available there, given the cold spring and summer, and that it is a shallow sea with purportedly not much input of heat and salinity from ocean currents?

Metamemesis

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Re: The 2016 melting season
« Reply #4089 on: August 18, 2016, 01:05:19 PM »
A pretty cool new visualisation tool, like nullschool.
https://www.windyty.com/

Awesome link, thanks! And it has ECMWF! Plus fasting loading, and option to pick the date/time.

Neven

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Re: The 2016 melting season
« Reply #4090 on: August 18, 2016, 01:43:14 PM »
Just an animation of before and after the storm. The rotation in the pack is really noticeable for just 3 days.

Here's some more detail.
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seaicesailor

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Re: The 2016 melting season
« Reply #4091 on: August 18, 2016, 01:48:27 PM »
Nice display pictured below of how the ice pack has been spinning around over the past 48 hours - something it is forecast to do a lot more of this month.

The source is http://osisaf.met.no/p/osisaf_hlprod_qlook.php?prod=LR-Drift-demo&area=NH.

I would say the divergence of the ice pack can also be seen. That is the Coriolis effect: the ice is spinning anti-clockwise, which is the same sense as the Earth's rotation as seen looking down on the North Pole, and so is also flying outwards.
Which makes clear the ongoing rate of melting, othewise this would be inflated as a globe.
If this is followed by compaction we could be getting very close to 2012 extent-wise too.
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slow wing

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Re: The 2016 melting season
« Reply #4092 on: August 18, 2016, 02:20:22 PM »
A pretty cool new visualisation tool, like nullschool.
https://www.windyty.com/

Awesome link, thanks! And it has ECMWF! Plus fasting loading, and option to pick the date/time.
Thanks also! It looks a very nicely designed and helpful site. Thanks to everyone involved.
For example, it has the wave height information that someone was asking for and I also find interesting.

The image has the pointer on one of the larger wave threats to local ice at the moment.

EDIT: also added a prediction for Tuesday, 23 August 2016 of 4.4m waves in the Siberian bite.  :o

EDIT2: see third graphic below - the forecast ends on Wednesday, 2016-08-24 at 1200, with 36 kt = 67 km/h = 18.5 m/s winds right next to the North Pole (this is an ECMWF forecast: the minimum pressure I found then in that storm was 967 hPa) :o

That would be 5 days out though, so still very speculative, as are the predicted 4.4 m waves at 4 days out.
« Last Edit: August 18, 2016, 03:02:14 PM by slow wing »

Sterks

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Re: The 2016 melting season
« Reply #4093 on: August 18, 2016, 03:06:58 PM »
What are the chances of four metre waves to reach the North Pole? There seem to be no ice cap anymore, only broken floes

Shared Humanity

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Re: The 2016 melting season
« Reply #4094 on: August 18, 2016, 03:08:11 PM »
Just an animation of before and after the storm. The rotation in the pack is really noticeable for just 3 days.

Here's some more detail.

The leading edge of the ice that is moving into open seas is melting everywhere. This is very pronounced with the ice moving towards the Beaufort. Also clearly visible with the ice edge along the Atlantic, from the Fram to Fran Josef.

Entropy101

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Re: The 2016 melting season
« Reply #4095 on: August 18, 2016, 03:17:27 PM »
This storm is really something! It pushes the remaining ice floes on the edge out over hot water where they melt, put a wave front with a good fetch length for the wind straight into the centre so we get a nice and good wave height and is churning up the waters considerably to make sure the ice that is not pushed out comes into contact with relatively hot and salt water.

seaicesailor

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Re: The 2016 melting season
« Reply #4096 on: August 18, 2016, 04:04:37 PM »
Getting closer..

And don't forget another near-GAC at D2


I must say this would be epic. I'm inclined not to believe it, but by irrational reasons (fear?)

That the map of ensembles show identical pattern and an average minimum below 980 hPa says a lot given the smearing effect of averaging. Still quite some uncertainty around the storm.

« Last Edit: August 18, 2016, 04:10:31 PM by seaicesailor »

jdallen

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Re: The 2016 melting season
« Reply #4097 on: August 18, 2016, 04:21:04 PM »
Observations (anectotal, I know) from recent days show raised temperatures (just below zero)
Cloud now shelters the ice from radiation losses, when the gains from incoming solar radiation are becoming small, trading lower gains for lower losses can be an advantage.
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jdallen

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Re: The 2016 melting season
« Reply #4098 on: August 18, 2016, 04:37:33 PM »
What are the chances of four metre waves to reach the North Pole? There seem to be no ice cap anymore, only broken floes
At this point, highly unlikely (to quantify, I'd say less than 1 in 50) but sadly a non-zero possibility.

And, yes, the structured tough ice we saw prior to about 2010 is very much gone.  For several years, at the end of the season what we've been left with is varying degrees of rubble which gets welded together over winter by much weaker first year ice.  What you are seeing this season is testament to that.
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Re: The 2016 melting season
« Reply #4099 on: August 18, 2016, 04:44:24 PM »
slow wing, If you check the Barrow web cam it shows some drift ice moving in but no waves. The
Winddyty  site shows something else. OK it is a forecast for tomorrow but I think some calibration of these wave forecasts may be available ( at least a visual calibration ). If no waves appear tomorrow I would begin to doubt the accuracy of the Windyty arctic wave forecasts.  Web cam does show wet ,
muddy roads and water on a flat roof so it must have rained ?