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Messages - Rubikscube

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51
Arctic sea ice / Re: What the Buoys are telling
« on: July 21, 2015, 06:17:12 PM »
PS 0buoy10 has turned to the left and now shows more buoys. azimuth, pitch and roll don't show any movement which stands out from previous behaviour, but it could be that the part of the floe it stands on has separated from the rest.

It looks rather implausible that the camera and buoys are separated. I can't find any cracks and would expect them to disappear out of view pretty quickly. My guess would be that the ice has melted around the camera so it floats around in a hole. The same seems to be happening at O-buoy 11 as well.

I find it pretty amazing that 2015b cam is still standing though. Barely any ice is left in its view now.

52
Arctic sea ice / Re: What the Buoys are telling
« on: July 20, 2015, 07:05:33 PM »
OBuoy 10 is back! That is after being absent for more than a month, and the surroundings look very different compared to the last picture from 12th June (last frame in the movie). NPEO cams also show heavily surface melting during past 48 hours, the volume loss should be significant, but with no recorded bottom melt there is no way what so ever this part of the ice pack will melt out before it goes down the Farm Strait come winter.

53
Arctic sea ice / Re: Northwest Passage thread
« on: July 17, 2015, 12:14:52 PM »
I'm wondering if we might not see the CAA fully melt out this year. Has that ever happened before?

Nope, the main channels north of Melville Island (Hazen Strait and Prince Gustav Adolf Sea), as well as Peary Channel north of Amund Ringnes Island have never been ice free at minimum.

54
Arctic sea ice / Re: The 2015 melting season
« on: July 16, 2015, 09:51:11 PM »
Per the following linked Cyclocane site & associated image Typhoon Nangka will be tracking towards the Bering Sea in the next several days; however, the Bering Sea is already relatively ice free.

The remains of typhoon Nangka should have some indirect impact though. It looks increasing likely that it will help to set up a very traditional looking dipole 3-5 days from now (high pressure in Beufort and Greenalnd and low pressure in Bering and Laptev), which make sure there are currently no prospects of melting conditions becoming unfavourable anytime soon.

55
Arctic sea ice / Re: The 2015 melting season
« on: July 16, 2015, 09:40:17 PM »
The 14th July average (2002-2014), 2015 vs average and 2015 vs 2012 ice concentration maps attached below show, among other things, that Laptev is no longer lagging behind the average, and that in spite of the current deficit of ice in Chukchi, there still seems to be quite some ground to make up if this year is to compete with 2012, not just in Baffin and Hudson. A peculiarity which has been present for some time is the abnormally high concentration of ice just east of Franz Josef and Svalbard, the later one is unprecedented in the AMSR-E/AMSR2 record going back to 2002.

56
Arctic sea ice / Re: What the Buoys are telling
« on: July 14, 2015, 08:47:55 PM »
Strong surface melt reaches Beaufort and Obuoy 10 and 11. Not just freezing at night and 10-15 hours a day of temperatures sulking around 0 (such as has often been the custom), but a full 24 hour cycle with a virtually continuos streak of heavy 1-2C readings. There is no sun to shine directly on the thermometers and the surface at Obuoy11 has gone bluish.

At the NPEO cams the situation is perhaps even more interesting. The melt ponds abruptly stopped expanding when a warm air mass intruded and the sun peeked through the clouds one week ago, but according to the ablation stakes the surface is currently melting at lightning speed despite the continuing lack of ponding.

57
uhm, I am not sure if I have my maths right, but the taller a glacier cliff is, the more prone it is to cliff failure and cliff+hydrofracturing. So I do not see how one should connect a tall cliff to stability. It is a main driver of dynamic behaviour...

Well, my thought was that the waters are too shallow, and that ice not really that tall, for cliff failure to be a major concern, and it doesn't seem like the cliff will get much taller than it already is. Thus I intuitively draw the conclusion that more ice takes longer time to export, which implies slower retreat (but not necessarily slower volume discharge). I'm not sure, it may be way too simplistic.

58
Much of the north face is grounded below sea level and the below sea level grounded portion goes fairly far inland.

I absolutely guarantee the north face is going to surprise us.

Looking at the north face in the most recent calving video, I'm struck by how tall it is. I can hardly imagine that this 3rd branch will be able to retreat very quickly through such a mountain of ice, after all, despite this area being grounded below sea level, it is quite shallow. There is also a second "cape ice" in the making which probably will result in two separate bulges in the north face, rather than one long calving front which could perhaps be somewhat unpredictable. Then again, I guess my inability to see where a surprise is supposed to come from, is also the reason I will be surprised :D.

59
Arctic sea ice / Re: The 2015 melting season
« on: July 12, 2015, 12:39:52 AM »
If the drift age model is to be believed then 2012 will not be reached again, there was a much greater export of MYI over this winter than in 2012. See week 27 to compare.
ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/age2012_27.gif
ftp://ccar.colorado.edu/pub/tschudi/iceage/gifs/age2015_27.gif

That really looks like a heavy burden to overcome, worst since 2007 I would say. At least the HP sitting north or Greenland is putting the ice into motion with its persistent winds blowing away from CAA.

60
Arctic sea ice / Re: 2015 sea ice area and extent data
« on: July 11, 2015, 01:25:09 AM »
850hPa is approx. 1500m altitude. For melting sea-ice that heat may as well be on the moon. I'll ask a question: 850hPa is at temp x. Is the surface at higher, lower or the same temp as x?7

Duh? I dare to claim that the amount of heat in the 850 hPa layer is more relevant to the sea ice melt than the amount of heat on the moon. As for your question, the answer depends on whether the underlying surface is ocean, ice or land as well as a whole range of other conditions such as season, cloudiness, altitude and the list goes on. Thats in fact the entire point of the 850 hPa temps; that they are relatively unaffected by the local surface conditions, and thus can be used to distinguish warm and cold air masses. So when an extremely warm air mass engulfs virtually the entire CAB one should expect melt rates at the surface to pick up, and I suspect that the recent failure to do so may be related to cloud cover.

61
Arctic sea ice / Re: The 2015 melting season
« on: July 11, 2015, 12:49:09 AM »
Where heat is present and floes separate then the amount of surface area the shattered pack presents to the ocean/atmosphere must increase ablation?

It's not as impactful as eyeballing it would suggest, because the floes are so darn thin compared to their other dimensions.

For example, suppose a 50km x 50km x 2m floe breaks into 2,500 pieces.
The surface area initially is (2500 km^2 x 2) + (50 x 4 x .002) = 5000.4 km^2 (.4 represents the surface area of the edges)

Afterwards, you have [ (1 km^2 x 2) + (1 x 4 x .002)  ] x 2500 = 5020.0 km^2 (20 represents the surface area of the edges)

So only a 4% [edit: make that 0.4%] increase in area from what looks like a total demolition of a large floe.

This effect will become significant when dealing with smaller floes though (such as 50m rather than 50 km), especially if you calculate exposure to the water line were the ice often appear to melt quickest.

62
Arctic sea ice / Re: 2015 sea ice area and extent data
« on: July 09, 2015, 10:30:37 PM »
The Chukchi has roughly extent of approximately 200k.  We see an uptick of 28k.  Is this strange or normal?

No.  The daily numbers have uncertainties that are likely 25% to 40% over the Chukchi at this point in the melt season.  I.e., the +28k probably has an uncertainty of anywhere from +/- 50k to +/- 80k.  So the 'true' value may well be -50k. 

Or the value from the day before may have been incorrect by -28k.  What we today is the 'true' value - meaning the number had to go up by +28k to correct for the previous number.

Bearing all this in mind a single day value increasing by 28k just simply is NOT surprising.  It doesn't matter whether you expect it to decline or not.  Math, statistics, and uncertainties simply dictate that you HAVE to see values like this.

Now, if we saw this for 5 days in a row - then I'd call it surprising.

Totally agree.

What I find most puzzling right now is that surface melt at the O-buoys and the North pole cam doesn't seem to correlate at all with the respective 850 hPa temps. The melt ponds at the pole apparently stopped expanding just when the heat should really start to pound the ice. I was expecting to see several more drops in the 150k range, but I'm not so sure anymore.

63
Arctic sea ice / Re: The 2015 melting season
« on: July 09, 2015, 12:50:18 PM »
Interesting comments about airborne black carbon's effect on the Arctic, from http://www.epa.gov/blackcarbon/2012report/Chapter2.pdf Section 2.6.4
(EPA report to U.S. Congress, no doubt appreciated ::) ).

"Over a highly reflective surface like the Arctic, BC particles absorb solar radiation and warm the atmosphere above and within the haze layer, while simultaneously contributing to surface dimming. Rather than a cooling effect from surface dimming, however, the atmospheric heating increases the downward longwave radiation and causes warming at the surface (Shaw and Stamnes, 1980; Quinn et al., 2008; Mauritsen et al., 2011). Any warming particle above a highly reflective surface can lead to heating of the entire surface–atmosphere aerosol column. In addition, the stable atmosphere above the Arctic prevents rapid heat exchange with the upper troposphere, increasing surface warming in the Arctic (Hansen and Nazarenko, 2004; Quinn et al., 2008)."
Thank you very much. That should settle the discussion.

The 850 hPa temps over CAB and Greenland will probably peak within the next 24 hours, but there will be a continued presence of abnormal heat in the high latitudes for a many more days to come. If one take into account the melt momentum and slight delay in SIA/SIE numbers, there is no reason to believe the drops will stall anytime soon.

It seems the heat finally touched down on Wrangel Island's only weather station as well. Yesterday's maximum temp of 18,1C is a mere 0,1 below the all time record for any date set way back in 1927.

http://www.pogodaiklimat.ru/monitor.php?id=21982&month=7&year=2015

64
Arctic sea ice / Re: The 2015 melting season
« on: July 08, 2015, 01:30:36 PM »
The question is; who much ash that has to deposit to make some real difference? In greenland inpurites accumulates over time and pop up every year, but the sea ice in Chukchi is supposed to melt within a couple of weeks and the albedo is already lowered substantially by ponding and increased amounts of open water. The loss in albedo that would result from increased melt when no ash is blocking the sun might even be the higher than loss of albedo caused by ash depositing in the ice.

65
Arctic sea ice / Re: Latest PIOMAS update (July)
« on: July 08, 2015, 01:04:13 PM »
Following Chris's useful data I thought I would try to come up with a way to represent it graphically.
I've reduced the data to 3 thickness buckets and then done a %age difference from 2017 for each different location. it produces some interesting views about how things have changed. 
Most interesting is the changing thickness in the arctic ocean where the lead up to 2012 can clearly be seen contrasting against the thickness this year.

Niiiiice!

But I suppose you mean 2007 and not 2017?

66
Arctic sea ice / Re: The 2015 melting season
« on: July 08, 2015, 12:44:42 PM »
SSTS have exploded in warmth again pushing into the Chuchki

So yeah here are SSTA with a Southerly flow pushing over the Beaufort open water towards the Chuchki with a Southerly flow pushing from the Chuchki open water to ESS.

I wonder how much such a pool of very hot surface water can contribute, and did contribute in 2012 and 2007, to bottom melt and volume loss during later stages of the melting season. Fragmented ice floes getting into contact with >5 C water would melt rather quickly I imagine.

Nice plume of smoke and the boundary envisioned by hycom GLB at 80°latitude becomes obvious.

Indeed, hypcom GLB clearly isn't pure fantasy, I would say it looks like a much better estimate than DMI and also better than hypcom ARC. But that smoke won't do much to melt the ice I suspect, it is just blocking the sun.

67
Arctic sea ice / Re: The 2015 melting season
« on: July 07, 2015, 07:20:59 PM »
If you compare the ablation stake yesterday (first image) and today (second image), it seems to be deeper today. Either the storm brought some fresh snow or the ice is so soft that the stake is digging itself deeper into the ice.

Definitely about 10 cm of wet fresh snow, quite amazing with such 850 hPa temps even though it is 5 a.m. or something up there. The snow will help, but the wind and waves might do some damage. Wonder if this weather hits Buoy 12 which sits just to the north of this camera.

Hmmm. I am pretty sure the stake is giving in, i.e sinks into the ice. Compare these two images

image 1
image 2
Sometimes I should look closer before jumping to conclusions :-[. You, and everyone else who pointed this out, are completely correct in your assertions.

68
Arctic sea ice / Re: The 2015 melting season
« on: July 07, 2015, 06:50:31 PM »
If you compare the ablation stake yesterday (first image) and today (second image), it seems to be deeper today. Either the storm brought some fresh snow or the ice is so soft that the stake is digging itself deeper into the ice.

Definitely about 10 cm of wet fresh snow, quite amazing with such 850 hPa temps even though it is 5 a.m. or something up there. The snow will help, but the wind and waves might do some damage. Wonder if this weather hits Buoy 12 which sits just to the north of this camera.

69
Arctic sea ice / Re: What the Buoys are telling
« on: July 07, 2015, 12:13:49 PM »
Obuoy9 can with pretty good certainty be pinned down to this floe of extra stubborn MYI. And notice how much difference there is on 2015B's ablation stake in the two posts above, approximately 7 cm (3 in) of surface melt in two days.

70
Arctic sea ice / Re: 2015 sea ice area and extent data
« on: July 06, 2015, 06:55:40 PM »
What's the granularity on CT again?  12.5KM?

It would be simply absurd to imagine that Wednesday increase is due to anything except for (1) sensors being fooled by surface conditions, (2) eccentricities of the algorithm or (3 - my favorite) ice breaking up at very small scales and spreading out.

(Edit: to my point - quick shot of detail around Wrangel island from yesterday.)

Considering the large drops during the last several days, it doesn't really seem that strange to have an uptick again, the maps Wipneus have been posting show that small upticks in concentration are quite usual, even on days with massive overall drops. It would be much stranger if ESS or Chukchi was gaining area again when these are the regions which are currently being pounded with heat, and it would be vary strange if this uptick is followed up by more slow days during this week.

71
Science / Re: Early Anthropocene
« on: July 06, 2015, 01:49:36 AM »
Thanks a lot ASLR, fabulous posts.

I sometimes wonder if there is any point in trying to put a date on the Anthropocene, not because I'm a nihilist, but because it seems pretty ridiculous trying to pin the transition down to an exact year or date when this is all part of the same ongoing transition without a know result. Moreover, it currently looks like humans are substituting the asteroids and volcanoes usually responsible for the transition between two eras rather than shaping an era of our own which we are entitled to name after ourselves. Maybe Anthropocene is just a transition period that we can neither call an epoch nor an era before the Earth Systems are stabilized and the ongoing mass extinction has ended?

72
Arctic sea ice / Re: The 2015 melting season
« on: July 05, 2015, 01:06:59 PM »
   But!....there seems to be over-excitement about ice melt,and  over-use of silly adjectives like the arctic is about to be 'toasted','roasted','nuked' ,'blow-torched' etc.., and then after all the fuss ,not much actually happens....
   Just my humble opinion!
   Phil

There are different opinions about this (it was also a topic of quite some discussion last year) and I can agree it sometimes is a bit unnecessary, but this time around I will be extremely surprised if nothing substantial happens. SIA actually dropped more than 200k yesterday according to Wipenus, I don't expect that to happen today since the intense heat has just arrived and is currently limited to ESS and Chukchi, but in 2-3 days from now it will be all over the place.

Arctic cap disappearance is the most spectacular manifestation of the greatest planet catastrophe for millions of years. It is natural that it attracts curiosity and excitement. It is a black swan of gigantic proportions.
I wouldn't go that far, ice-ages were much more "catastrophic" than some changes in sea ice. Also if one takes the "long view" it is inevitable that the climate will change, even without human intervention. This time it's happening rather quickly and adaptation might get difficult.

I believe he said that the arctic melting is just a spectacular manifest to the greatest disaster in a long time, and thus this disaster is humans messing up the earth and not the ice melting. Seems perfectly true to me.

73
Arctic sea ice / Re: What the Buoys are telling
« on: July 04, 2015, 11:32:44 PM »
It's starting to look pretty barren around 2015B, and looking quite vulnerable to wind/wave action.

74
Arctic sea ice / Re: The 2015 melting season
« on: July 04, 2015, 10:32:14 PM »
Get excited when this is an actual temperature rather than a forecast.
There is actually a weather station at Wrangel Island to measure real temps and it isn't registering anywhere near 20-30C, but I suspect that is because the station sits at the coast where the southern breeze is blowing air straight off the melting ice/cold ocean. Modeled surface temps across the ice free interior should be a pretty good indicator of how much heat there is hanging around, but of course it isn't exactly a flawless approach.

Just for fun, I counted pixels and put this in rough numeric terms.
I had incorrectly posted as area initially, but I was counting pixels >15%
           Extent     Change
July 3rd     9,341   
July 4th     9,251     -90
July 5th     9,143   -108
July 6th     8,714   -429
July 7th     7,991   -724
July 8th     7,659   -332
July 9th     7,351   -307
July 10th   7,151   -201
July 11th   6,934   -217
That's an awesome experiment, even though a 700k day won't happen before pigs fly.

75
Arctic sea ice / Re: The 2015 melting season
« on: July 03, 2015, 10:56:39 PM »
Both GFS 12z run and the ECMWF 12z run suggests a major high pressure at 1025-1030 hpa building in over the Arctic and a kind of dipolar set up for the next week. The coolest air at 850 hpa level will continue to be confined mainly to the fringe areas in the Atlantic sector.

The latest ECMWF did indeed take a great leap towards the "sledge hammer solution" with the Pacific and Siberian heat linking up in about 120 hours from now (within the edge of reasonable reliability) to basically cover the entire CAB for as long as the models can see.

And how about this forecast: a light southern breeze, crisp sunshine and temperatures peaking at a comfortable 24C, yes you probably guessed it, that's tomorrow on Wrangel Island in the East Siberian Sea. If this don't end in disaster then I understand nada.

76
Arctic sea ice / Re: The 2015 melting season
« on: July 02, 2015, 08:29:31 PM »
If I may ask, any changes of the weather prospects during the past two days?

Sounds like an apropriate question to ask. First, the thing that seemed very plausible two days ago is now almost certain to become reality, that is (to steal one of frivs colorful expressions) the Pacific side is about to get "nuked". In about 36 hours from now, a massive heat wave will enter ESS and grow to cover most of the Pacific side by the 120h mark, after which forecasts start to shake, the 850 hPa temps will be beyond anything I can remember seeing up there, for a sustained time period at least.

The longer term forecasts are now trying to decide whether or not this Pacific heat dome will be able to link up with other pools hot air over central Siberia and Greenland in order to put virtually all of the remaining sea ice under one big sledge hammer. Yesterdays 12 run featured such a linkup in its "fantasy range", but despite todays 00 being almost the opposite it still features strong melt throughout the entire run. For melt intensity is to return to normal or below normal by July 10th, one both have to chase away the pacific heat and block more heat from entering the arctic somewhere else. Something which seems possible, but highly unlikely.

Even though one can presume July will be of to a flying start, there is a lot of catching up to do (area and extent wise at least). The maps attached below show the average sea ice concentration for July 1st (2002-2014), 2015-average and 2015-2012 respectively. It now looks like the total amount of ice in the central regions is pretty average (slightly ahead maybe), but actually 2012 isn't terribly far ahead. Baffin and Hudson are apparently inflating the numbers pretty significantly, more so than Kara is pulling in the other direction, at least compared to 2012.

77
Consequences / Re: Global Surface Air Temperatures
« on: June 30, 2015, 04:45:57 PM »
The latest daily AMSU temp (June 27th) sets an all time record for any date. Though, it is to be said that this reading is from ch06 which measures temps at 7,5km (25 000 ft) altitude as neither ch04 or ch05 are reporting anymore. Don't know how much you should put into these numbers, but they have previously proven to be a good indicator of the monthly UAH temps at least.

https://ghrc.nsstc.nasa.gov/amsutemps/amsutemps.pl

78
Arctic sea ice / Re: The 2015 melting season
« on: June 30, 2015, 04:08:16 PM »
The forecast of weather conditions conducive to melting (ie a high over the American-Pacific side of the Arctic) seems to be coming closer, but it's still far out. Even so, there's plenty going on as it is. The question is: how much is hidden beneath the surface? How much potential is there?

The runs (both yesterdays and todays) start out pretty normal only to get worse and worse for the ice the further out they go. This means that the most spectacullar and destructive setups are also the least likely, but even at a reliable 96h, the conditions are favouring strong melt.

Its worth noticing that virtually every run in the last couple of days have yielded similarly apocalyptic scenarios in the 168h+ range, and I don't think that is a coincidence. Usually these huge warm air intrusions are forecasted when there is a scenario with a massive anti-cyclone, often accompanied by a moderate arctic cyclone, to create a strong pressure gradient that is remarkably stable. What happens then is that even slight changes in the systems strength, position and stability causes the predicted torch to weaken dramatically maybe even fizzle out and disappear entirely. However, this time it seems like the heat sources are so abundant and so ideally positioned that even ordinary looking setups with remarkably weak pressure gradients are capable of producing wild scenarios. If you compare yesterday's ECMWF to the 00 from today, you will the that the runs differs quite a lot when you do beyond 168h, but they all spell disaster for the ice because there is so many differnet ways of getting there.

The caveat is for course that there is always a significant chance that a long term forecast abruptly desides to flip flop, but with so little snow cover left, the likelyhood of a July cliff unlike anything ever seen looks as big as it can possibly get on a June 30th.

79
Really appreciated with such extensive answers. I was foremostly thinking about topography because it tells about the potential for future acceleration in speed and volume discharge, but I recon it will be extremely difficult to make a more precise definition of iceshed (based on volume) especially when the timescale of a GIS collapse in unknown.

80
Arctic sea ice / Re: The 2015 melting season
« on: June 29, 2015, 09:11:17 PM »
IF the forecast holds, there will be a huge WAA over Chukchi and ESS in about 5 days. In Beaufort HP dominated weather will make its presence..

In about 6 days, a heat dome will reach Hudson and toast the ice in combo with some winds too...

Baffin is under fire too soon...

Single, double or triple century breaks anyone?

//LMV

The ECMWF 12 run is a carnage. 168h+ is completely absurd, but it starts from the very first day in July. Century breaks are guaranteed.

81
Zachariae etc are very important to get right because the huge iceshed -- 16% of Greenland -- could potentially be a big contributor to future sea level rise. Without knowing the interior physics of NEGIS, it is difficult to predict its acceleration in respnse to removal of marine buttressing. (For comparison, Jakobshavn drains 8% and Petermann just ~4%.)
Is this an estimate exclusively based on current flow rates, and the respective ice thickness, with little or no regard for the underlying topography? 8% to Jakobshavn seems like a terribly low estimate.

82
Greenland and Arctic Circle / Re: Greenland 2015 Melt Season
« on: June 26, 2015, 10:51:53 PM »
Still just about 30% of Greenland experiencing surface melt according to both NSIDC and DMI. Can't quite see why there is so little melting in the south, but at least the heat elsewhere shouldn't be going anywhere anytime soon.

And there a weather station on Hans Island :o

83
Arctic sea ice / Re: The 2015 melting season
« on: June 25, 2015, 10:39:10 PM »
There is almost no predictability of the June extent for the September extent, once the underlying trends are accounted for, as can be seen by looking at this data taken from the National Snow and Ice Data Center (NSIDC).

That was not exactly what I was trying to say in the first place, but it's certainly an interesting discussion on its own. Basically; very favourable melting conditions this time around (in the sense that they contributes both directly and indirectly to the minimum) always result in substantial losses of SIA, although substantial losses aren't necessarily a consequence of very favourable melting conditions.

84
Arctic sea ice / Re: The 2015 melting season
« on: June 25, 2015, 02:07:54 PM »
My view is that we should not be blind for the SIE numbers and the lack of century breaks. Yes, there have been few centuries but that should be assigned to the cool weather in Labrador Sea and to some degree also Hudson Bay. Both these areas suffered, as we all know, a very cold winter. Earlier years melt seasons had higher extent numbers which should have contributed to the number of century breaks.
Part of my point is that people can't start putting less emphasis on SIA/SIE number whenever they are stalling and not producing the spectacular cliffs most of us want to see (I presume), especially not when there is such an outcry each time double and triple centuries start ticking in. Secondly, while it is correct that Baffin and Hudson currently inflates the numbers slightly, in the sense that the final outcome of these regions is more or less given, you also have to account for Kara which at the moment is way ahead of most year.

Friv's maps gives you the situation at the moment; lots of heat sulking around on the fringes, but for most of the sea ice there is little melt. Take a look at both the O-buoy 11 and 12 cams as well, no rain, no sun, but a blanket of fresh snow. These aren't conditions that favour melting.

I think we should introduce a new terminology now:

WAC: "Weak Arctic Cyclone"
MAC: "Moderate Arctic cyclone"
SAC: "Strong Arctic Cyclone"

From earlier years we have "GAC" and "PAC" --> Great Arctic Cyclone and Persistent Arctic Cyclone :)

//LMV
Hmm, that sounds like a great idea :).

85
Arctic sea ice / Re: The 2015 melting season
« on: June 25, 2015, 09:50:22 AM »
I'd quibble with you Rubiks; Looks more like favorable melt conditions, not unfavorable.

Two shots from Climate Reanalyzer for today, temp and clouds.  It's no better over the next 3-4 days.

I just don't see it. Yes there will be some melt and yes I agree its much more heat around compared to 2013 and especially 2014, but when there is no HP domination and the air mostly keep circulating within the arictic (like will be the case during the upcomming 48 hours at least), then the melting conditions are not favourable. On top of that you've currently got winds pushing the super heated surface waters in Chuckhi away from the pack.

It is solstice, it is seemingly very little snow left and there are pools of warm air to tap into in every direction, still neither area or extent can do a proper century break and that is not because these metrics are useless, it is simply because melting conditions are unfavourable.

86
Arctic sea ice / Re: The 2015 melting season
« on: June 24, 2015, 08:10:17 PM »
All of this is a week out. What does it look like for the remainder of June?

Not very favourable for melt I would say, except for Greenland of course. Pacific side is going to be cold and cloudy with winds blowing the pool of extremely hot surface water away from the ice and towards the Bering strait. Some heat will be sneaking around on the peripheries though.

It is to be said that the monster pattern starts building before the end of June in ECMWF's 00 run, so the cold shouldn't last too long. I'm super exited to see whether the forecasts hold and will be joining Friv in the prayers :D.

87
Greenland and Arctic Circle / Re: Greenland 2015 Melt Season
« on: June 23, 2015, 10:43:26 PM »
The hammering has just begun, with no end in sight. I will almost expect NSIDC melt to cross into >50% territory and stay there.

88
The 2014 calving front is the one showing greatest retreat for the date. This might be because the ice stream is advancing faster this year relative to rate of calving in the 'new abnormal' of stationary cold weather.

It seems quite logical that a glacier like JH, which behaves so differently from month to month (unlike other glaciers like Zach, which can keep retreating at a steady phase in the midst of winter), is also more likely to respond to 5-6 weeks of abnormal cold by significantly slowing down its rate of calving. Either way it seems the "new abnormal" is finally about to end, ECMWF puts most of Greenland on 10 days of continuous roasting, starting from today.

89
Arctic sea ice / Re: The 2015 melting season
« on: June 18, 2015, 04:05:09 PM »
Ok, I'll admit, I am completely stumped as to why there is such a large contradiction between sources of data this year. Both DMI and NSIDC concentration maps seem to show concentration dropping into the central Arctic, suggesting significant melt pond coverage. Yet, in some noticeable enigma, your source doesn't have it.

My best guess is that your source uses AMSR2 and is picking up cloud cover again. In that case we should not conclude that this year is behind 2012.

I've been bit sloppy specifying my sources lately, but I'm allways using the standard 2,5x2,5 grid products provided by Uni-Bremen (a caveat is that I go straight to the TIFF files and not the more accurate HDFs since don't know how to properly attend for its vast amount of numerical data). This means 2002-2011 is AMSR-E and 2013-2015 is AMSR2. 2012 is only available in SSMIS until late July, and comparing an SSMIS to an AMSR2 might perhaps be a more dubious exercise, but Uni-Bremen at least doesn't provide any alternatives.

It is worth noticing that the color scale that I use in my delta maps somewhat exaggerate small differences (5-50%). My initial idea was to emphasize melt ponding and put a distinct line at 50% difference, but it probably makes the difference to 2012 look more brutal than it really is as well. Please let me know if you think my color scale is misleading and want me to adjust it.

Are we integrating red vs blue dots by eyeball, or do we have a pixel by pixel integration?

There are many different sources providing area and extent numbers, most notably Wipneus. I don't have the skill to engage is such activities either, so this only serves as a year-to-year visual comparison.

What is really fascinating to me about the negative anomalies is occurring in the Baffin, CAA and Hudson. This area had a brutally cold winter which you think would have caused the ice to be resilient during this melt season. Even more peculiar......the negative anomalies are in the northern regions of the Baffin and Hudson. What could be causing this?

I think an unusual wind setup with lots of cold air flowing south from CAA is the most likely answer.

90
Arctic sea ice / Re: What the Buoys are telling
« on: June 17, 2015, 10:57:15 PM »
Speaking of ablation stakes; the last one visible on 2015A disappeared without a trace today, could it be that it simply slipped through the ice?

Edit: you have to give it a click.

91
Arctic sea ice / Re: The 2015 melting season
« on: June 17, 2015, 09:48:11 PM »
These are the 2002-2014 average (2012 excluded), 2015 vs average and 2015 vs 2012 ice concentration maps for 16th June.

Most of the negative anomaly is actually in Kara sea and notice as well the anomalies north of Franz Joseph and Severnaya Zemlya. 2015 is also ahead in Chukchi and Beaufort although the gap is not extraordinary. Laptev is lagging behind still (but the anomaly south of the New Siberian island is probably not very indicative at this stage of the season) and Baffin ever more so with a significant patch of positive 100% anomaly. Lots of ice east of Greenland too.

2012 is significantly ahead of 2015 at this stage, as one could expect looking at the number. The difference can of course be made up for during the course of the season, but crucial regions like Beaufort and Laptev have apparently gotten a rather massive head start.

92
Arctic sea ice / Re: The 2015 melting season
« on: June 17, 2015, 04:13:05 PM »
I have checked back to see the reanalysis maps for the snow data, and they do line up reasonably well with the former forecasts. You're being very uncharitable to assume that I never even looked and to equate this to denialism, but just to give one example (upper image is forecast with 7-day lead time, lower image is reanalysis):

Thank you very much. Sorry for my harsh response, but some snow cover forecasts have seemingly been overestimating the snow melting quite grossly so when you only post longterm forecasts I start suspecting you are picking cherries. I see now that you have to reason to do so either, the reanalysis aligns remarkably well with the 7 day forecast.

93
Arctic sea ice / Re: The 2015 melting season
« on: June 17, 2015, 02:18:57 PM »
Nightvid and Vergent.

I find it annoying that you guys always pick a 7-10 day forecast when examining the TOPAZ4 snow cover data, especially when making comparisons to previous years. Even more so when you never revisit those forecasts 7-10 days later to see what the result actually was. It is great that someone posts this data so we can discuss it, but the way the data has been presented by you border to cherry picking and comparison on unequal terms, the kind of unserious approaches I usually associate with deniers.

94
Arctic sea ice / Re: What the Buoys are telling
« on: June 16, 2015, 11:11:12 PM »
I could swear that was fresh snow on O-buoy 11 hadn't it been for that instrument to the right. The sub-zero temperatures correlate with increased winds, maybe its just a thin layer that mostly blew of the areal?

As for 2015E, I find no reason to question your understanding of fluid dynamics, bottom melt has seemingly not been progressing very fast there since my last post, but the ice is steadily warming as it pases through what appears to be swirls of warm and salty waters. Currently, all the sensors there read -1,82C or higher.

95
Arctic sea ice / Re: The 2015 melting season
« on: June 15, 2015, 11:13:27 PM »
The forecasts are very exciting despite moderate low pressure activity, lots of warm air is going to be dragged in on the southern flanks of these systems to hammer the pacific side. And the 168+ forecast is a wild beast, I will certainly be disappointed by the 00 run tomorrow morning :).

96
Arctic sea ice / Re: What the Buoys are telling
« on: June 14, 2015, 02:29:10 PM »
are you taking distance from Worldview, rubikscube, or are there other ways to measure them?
Yes, I was using worldview to make that estimate, but I think I mixed up between longitude 1.47 and -1.47  :). The buoy is still about 40 km away from the open ocean, but closer to where one would expect to find such warm waters.

It may be the ice is warming faster around the drill hole where the sensors are, but I would assume that is an effect usually associated with surface melting.

97
Arctic sea ice / Re: What the Buoys are telling
« on: June 14, 2015, 09:56:51 AM »
2015E which sits north west of Svalbard (but more than 50 km from the ice edge!) is in such warm waters that it could melt out before July.

98
Arctic sea ice / Re: Arctic Image of the Day
« on: June 11, 2015, 06:07:31 PM »
Looks like a layer of fresh/recent snow but the snow seems kind of wet?

Yes, it seems like the skies have just cleared after a snowfall. Don't think the snow is wet though, it has been below 0 all day. The darker patches are older melt ponds with snow on top

99
Arctic sea ice / Re: Arctic Image of the Day
« on: June 11, 2015, 05:44:57 PM »
A spectacular picture from the O-buoy12 cam.

100
Arctic sea ice / Re: The 2015 melting season
« on: June 09, 2015, 04:06:04 PM »
It is certainly quite early, but not as much as it might seem. These melt pond related (i presume) low concentration areas are actually such an usual occurrence on the fast ice south of the New Siberian Islands that the average Uni-Bremen ice concentration there is significantly lower on 16. June than it is on 1. July.

Yes, but always green and yellow, not blue.

Anyway, I noticed it by accident while looking at the crushed ice in the Beaufort, because that isn't really usual either:

Very much agree with you there.  In this case, I think the state of the ice is at least a month ahead of similar conditions in the past; perhaps two.

With all respect I think you both need to freshen up your memories :). This one, from 2006, is one of the more extreme examples, but if you go through the archives and cherry pick the right dates you can make similar comparisons involving sizable areas of >50% and even >20% concentration from virtually any year. 7th June is rather early though, and the breakup of M'Clure Strait fits in the same category; early, but not totally unprecedented. Thus, I would rather say we are a week or two ahead of most years.

That said, things seem to be speeding up dramatically at the moment. I really didn't expect to see every buoy report such heavy melting during the past 24 hours, and according to ECMWF it might soon be time to issue a "dipole alert". I'm actually going to revise my minimum votes down a couple of notches.

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