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Messages - slow wing

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551
Arctic sea ice / Re: The 2015 melting season
« on: July 09, 2015, 01:10:28 AM »
JDAllen & Gerrit,

   There should be plenty of data to directly determine the maximum Arctic ice ablation rate in sunlight, from the instrumentation on the ice, and to compare with JDAllen's estimate of 6 cm/day based on insolation energy data.

For example, Rubikscube has recently posted on an observed ablation rate of 3.5 cm/day
http://forum.arctic-sea-ice.net/index.php/topic,327.msg55836.html#msg55836


Jim Hunt, what is the maximum ice ablation rate you have observed due to sunlight?

552
Arctic sea ice / Re: Arctic Image of the Day
« on: July 07, 2015, 10:16:53 AM »
Yes, nice image!

553
I want to see what the impact of the coming weather will be. If there's something that resembles a cliff, I'll go down a bin again. Perhaps even two.

Because remember, everyone, you can change your vote up until July 12th.
Yep, i'm relying on that...  :P

The new PIOMAS volume is so much higher than in 2012 that I might be heading in your direction...  :)

554
Arctic sea ice / Re: Latest PIOMAS update (July)
« on: July 04, 2015, 12:52:11 AM »
Regarding Nightvid Cole's & Steven's posts, a quick comparison shows PIOMAS might have been a little thicker in the Chukchi & Beaufort than CryoSat actually measured, when compared for May 2015. (Cryosat couldn't measure any later in the Summer due to melt ponds.)

Wipneus posted the May PIOMAS thickness reconstruction here...
http://forum.arctic-sea-ice.net/index.php/topic,119.msg53274.html#msg53274

While the roughly corresponding map from CryoSat is here...
http://www.cpom.ucl.ac.uk/csopr/seaice.html

Probably the best comparison is to click on "14 days", which shows 5-19 May for Cryosat.

The Chukchi Sea for that plot is, very roughly speaking, mostly a mix of green & yellow areas, which is, respectively, the 1.75-2.00m and 2.00-2.25 m thickness bins.
So the average looks about 2m.

For comparison, PIOMAS in the same region shows mostly the 2.00-2.25 bins, with some thicker but little in the yellow 1.75-2.00m thickness bin.


So, at first glance, PIOMAS looked slightly thicker there than the CryoSat measurements, perhaps by of order 10%. This is hardly surprising given the model and measurement uncertainties.


That was just a quick eyeball comparison. I'm sure the scientists themselves have done a more thorough comparison.

555
As explained in the 'extent poll', I'll stick with a prediction of close to 2012, just a little bump up of 0.1 million km2. This actually bumps it up one bin, to the 2.25-2.250 million km2 as the 2012 value is near a bin edge.

With 1-sigma uncertainties, I predict 2.3 +/- 0.7 million km2.

556
  Because I don't know any better, I'll persist with last month's prediction of a strong melt season with a minimum similar to 2012, so the bin for between 3.50 and 3.75 million km2.

  Present extent & area really don't matter for predicting a minimum. It's the state of the ice in the CAB that matters, along with whatever hints we have of a weather forecast.

  It's been cloudy but windy lately, so probably better than cloudy and still but not as good as sunny. To somewhat compensate, forecasts are for strong melt-inducing weather over at least the next week or so.

  For what it's worth, a cliff appears imminent in both extent and area. This is partly due to that forecast but mainly due to catching up in the Hudson and Baffin, augmented by lots of ice that looks ready to go on the Siberian side as well as some in the CAA and Greenland, Chukchi and Beaufort Seas.

  So the extent and area graphs might take a spectacular dive very soon, but the uncertainty will still be large in the melt season minima.

  With 1-sigma uncertainties, I predict a minimum of 3.7 +/- 0.9 million km2.


557
Policy and solutions / Re: James Hansen loves nuclear power
« on: July 01, 2015, 02:19:45 AM »
This is just dumb. Japan gets quakes of magnitude 5 extremely often - several a month. The quake that devastated Japan was roughly 10,000 times larger. I'm not saying there aren't issues for Japan nuclear but an article hyping a magnitude 5 because it is on an anniversary or on a day plants restart is just silly and not news worthy.
A couple of points:

1) the Tōhoku earthquake, of magnitude 9.0, and tsunami causing the Fukushima Daiichi nuclear disaster was actually more than 100,000 times larger in energy released than the recently reported magnitude 5.6 quake - see definition here:
https://en.wikipedia.org/wiki/Moment_magnitude_scale
(note the "2/3" factor in the defining equation)
That would tend to support your argument, but...

2) prior to the Fukushima disaster, another power plant (Japan's biggest) had already been shut down in 2007 after a nearby earthquake of magnitude 6.6 - i.e. only 30 times the energy of the recent quake and only 1/4000th of the energy of the Tōhoku earthquake. The plant was completely shut down for 21 months and 3 of the 7 reactors were never restarted.
https://en.wikipedia.org/wiki/Kashiwazaki-Kariwa_Nuclear_Power_Plant


  With Japan so active seismically, it's really just a question of when the next seismic nuclear disaster will be whenever nuclear power plants are in operation.

  More than 4 years after the Fukushima disaster, Japan still has all nuclear power plants shut down, though 24 of the 50+ reactors are in the process of restart.
http://www.theguardian.com/world/2015/apr/22/japan-moves-nearer-to-restarting-nuclear-reactors-after-court-gives-go-ahead
http://www.world-nuclear.org/info/Country-Profiles/Countries-G-N/Japan/


  In my view, Japan should not restart nuclear power but should instead move aggressively towards 100% sustainable energy technologies.


558
Arctic sea ice / Re: The 2015 melting season
« on: June 27, 2015, 03:03:11 AM »
The CA experienced a brutally cold winter ... I still believe that early, heavy snowfall last fall insulated the ice from the severe  cold of the winter.
Maybe the snow insulation caused the brutally cold Winter?

The snow cover would have minimised heat flow up through the ice from the Arctic water underneath, so the air temperature above would be determined more by the (very cold) temperature of the Arctic Winter sky.

Reasonable analysis?

559
Arctic sea ice / Re: 2015 sea ice area and extent data
« on: June 26, 2015, 12:49:22 PM »
Someone's plonked down a giant spade next to Greenland and scraped a furrow in the ice all the way to Siberia!

560
Arctic sea ice / Re: 2015 sea ice area and extent data
« on: June 26, 2015, 09:34:04 AM »
Morning guys!

I just found this interesting product with perhaps a daily calculation of the volume in the Arctic basin in combination with a estimated ice thickness. Have you seen it before? What kind of value does it have?

http://ocean.dmi.dk/arctic/icethickness/thk.uk.php

http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE_combine_thick_SM_EN_20150625.png

This is another map of the modelled ice thickness including a forecast for the next 5 days. Of interest is only the Arctic Sea and to some degree Greenland. Unfortunely, the five last parameters don't work for the Arctic Sea.

http://ocean.dmi.dk/anim/index.uk.php

Most interesting is the forecast of the sea ice thickness around the North Pole which is foreseen to be less than 1,5 m by June 30....

Oh, finally a link to satellite images around Greenland including Nares Strait :)
http://ocean.dmi.dk/arctic/morrisjessup.uk.php

and a link to Greenland ice charts. http://ocean.dmi.dk/arctic/icecharts_gl_1.uk.php

Sincerely, LMV
Nice find!
Maybe others are already familiar with it, but a daily updated ice thickness map is very interesting!

PS it says it uses the DMI HYCOM-CICE model. How is this related to the CICE model that is linked to Neven's graphs page & appears here:
http://www7320.nrlssc.navy.mil/hycomARC/arctic.html
?

561
Arctic sea ice / Re: The 2015 melting season
« on: June 26, 2015, 06:16:38 AM »
PS someone said 2015 is looking a lot like 2011 and, yep, I can see that:

http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=06&fd=17&fy=2011&sm=06&sd=17&sy=2015

562
Arctic sea ice / Re: The 2015 melting season
« on: June 26, 2015, 06:11:55 AM »
Does anyone else play the game on Cryosphere Today, Compare Daily Sea Ice: 'how many days behind 2012 is the 2015 sea ice?' ?

Most recent date displaying there is 17 June 2015, and I say: 8 days!

http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=06&fd=09&fy=2012&sm=06&sd=17&sy=2015

 :o

563
Arctic sea ice / Re: The 2015 melting season
« on: June 24, 2015, 12:30:55 AM »
Sure there's a lot of heat around the edges of the Arctic Basin. But, mainly, June has been cloudy due to low pressure systems so there hasn't been much direct sunlight beating down on the ice pack. We've just passed the solstice  so this is the 1-2 month period where direct sunlight is most important. So imo the recent weather has not been favouring an exceptional melt season.


564
Arctic sea ice / Re: The 2015 melting season
« on: June 20, 2015, 03:57:08 AM »
Climate Reanalyser shows lazy low pressure systems hanging over the Arctic Ocean proper for at least the next several days.
http://cci-reanalyzer.org/Forecasts/

Persumably this underlies the present pattern in the jet stream. Over what timescale might this be expected to endure?  A significant part of mid-Summer?

565
Arctic sea ice / Re: The 2015 melting season
« on: June 18, 2015, 01:48:15 PM »
Oh yes, now I see "precipitation & clouds" also on that current weather link.

566
Arctic sea ice / Re: The 2015 melting season
« on: June 18, 2015, 12:49:03 PM »
One of the things I've been trying to do this year is to figure out where under the cloud cover there is precipitation going on, and whether it is rain or snow. Until nullschool came along that was not clear to me at all...
Are you familiar with the Climate Reanalyser displays?
Can see the places with rain and snow here...
http://cci-reanalyzer.org/Forecasts/
Choose
1) "Arctic" as Region
2) "Precipitation & Clouds" as Parameter
That is actually forecasts. Nearest to current is 3 hours in the future.

I haven't yet found the same information on the current weather display. It should be there? Am I missing choosing the correct parameters?


567
For reasons given on the companion 'Extent' thread - at  http://forum.arctic-sea-ice.net/index.php/topic,1281.msg54015.html#msg54015 - I'm going for a big melt season and  with the 2012 record low value as my central value, with large uncertainties.

So 2.24 million sq km, which is the 2.00-2.25 bin.
With one sigma uncertainties, I would guesstimate about a 2/3 probability of end up in the range 1.4-3.0 million sq km.

568
Have to predict now before poll closes but large uncertainty.

Imo current extent is more or less irrelevant as it is dictated largely by seas on the periphery, e.g. Hudson Bay, whereas the CAB determines the melt season minimum.

Frustrating to not know the volume very well, with different determinations - PIOMAS etc - disagreeing.

Each year it is a race as to whether any particular area melts out before the end of the melt season. The CAB appears to be off to a good start. The following factors support a big melt out this year:
1) the snow cover has already disappeared over most of the ice in the CAB - appears to be earlier than in at least most of the recent years;
2) Both Alaska & Siberia have been relatively hot recently & the winds & rivers will continue to transport this heat & fresh water to the CAB;
3) winds are currently transporting ice out the Fram Strait.

Given all of the above, and unaware of any compensating negative indications, I think it will be a big melt year.

So I went with same as 2012: 3.66 million sq km, which is the 3.50-3.75 bin.
With one sigma uncertainties, I would guesstimate about a 2/3 probability of end up in the range 2.7-4.7 million sq km.





569
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: June 14, 2015, 01:15:33 AM »
Great stuff!  :)

570
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: June 13, 2015, 04:34:59 AM »
Yes, Lord Vader & seaice.de, that sounds like a good explanation, thanks.

571
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: June 12, 2015, 02:03:38 PM »
Weird! Could it be real ice? Like a huge pressure ridge that resists melting?
Or is it too stable and stationary for that? Maybe instead being a software artifact?
Isn't the sea shallow near the Siberian Coast? So could it be something anchored or attached to the sea floor? A vein of methyl clathrates??
In summary then: weird!

572
Arctic sea ice / Re: The 2015 melting season
« on: June 11, 2015, 01:25:23 PM »
Michael and Werther, thanks for the detailed and informative replies to my questions, much appreciated!  :D

573
Arctic sea ice / Re: The 2015 melting season
« on: June 11, 2015, 05:41:51 AM »
Whatever ‘meltpond-june’ may or may not bring, the recent large Low has had an effect on ice distribution in the CAB.



This 500 km radius circle around the pole is from today’s MODIS, enhanced picture (bright -10/contrast +22/mid-tones -64). It shows a lot of torn leads and open water, as the surface winds have dispersed  while compacting elsewhere. It looks like the large swath of thinner ice in the ‘Laptev-bite-to-come’ has been messed up most.

Within two weeks a first assessment on this melt season can be made, at least, IMHO. I’m looking forward to do a first good analysis.
The early range of lowest extents hasn’t convinced me that an extreme low is in the box. The range was related to an anomalously warm Pacific. There’s a good chance Pacific influx will continue. There’s also reason to expect warmer air temps, as have occurred lately over the Kara/Barentsz Seas. There’s a lot of, quite early, melt-ponding on fringes in the peripheral seas. Much depends now on the return of sunny weather and southern winds , especially over the Laptev Sea.
Very interesting image!

How unusual is that level of break-up around the pole at around this date?
For how many years back do we have the satellite images to know that?
Do we know how broken up the ice actually is?
For example, a ripple pattern with a period of a couple of km can been in the segment from 10-12 o'clock. Does that mean a whole lot of parallel leads but with the ice maintaining integrity inbetween? Or not?
And in the 'Laptev bite' region, what can we see about the size distribution of ice chunks? Could it go all the way down to 'slushee' in some places?
Are there higher resolution images available to determine this?

At first look it is very interesting to see such an image this early in the melting season, so thanks in advance to anyone who can answer any of these questions.

574


The arctic albedo is at least 20% below 2012. The area is the same. That corresponds to 100 watts in full sunlight. Discounting it to 50 watts for cloud cover, that will still melt 0.8 meters of ice over 60 days. Over 9 M km^2, that corresponds to 8 kkm^3. Eyeballing PIOMAS, that would put us in negative numbers. The poll didn't have negative numbers, so I picked the bottom bucket.

Verg
Tbf that assumes the abedo will remain 20%+ below 2012 for the next 60 days.

Wouldn't the albedo instead have fallen off soon afterwards in 2012 due to the melting of most of the remaining snow cover?

575
Heh heh! Very good, Geoff, I enjoyed the poem as well  ;D

576
Aluminum is "smelted" using electricity almost always using hydro power.
I would tend to accept that. But do you think the reference cited by Geoff Beacon above takes that into account?

I'm guessing the 'intrinsic' embodied carbon in car manufacture is relatively small - that is, electric cars can be produced sustainably or nearly so if we put our minds to it.

Let's take it further and ask what it is in electric car manufacture that must release CO2 or other greenhouse gases, with no manufacturing alternative.


Challenging Geoff Beacon or anyone else to nail that down if they can. (Do it in ALL CAPS if that's your style.) Personally, I'm skeptical of these reports and their calculations.

577
To be fair, the embodied carbon from manufacturing the vehicles is probably largely from fossil fuel energy - for example in smelting aluminium. That contribution can presumably be zeroed out by using renewable energy.

578
Arctic sea ice / Re: The 2015 melting season
« on: May 26, 2015, 01:28:14 PM »
These Nullschool graphics have been a game-changer for helping me to visualise changes in the Arctic  this season compared to previous seasons.

Winds over the past week or so have transported heat from the Alaskan, and nearby Canadian, land mass over much of the Central Arctic basin. This has been so much easier to follow using the following Nullschool display:
http://earth.nullschool.net/#current/wind/surface/level/overlay=temp/orthographic=-35.44,93.43,1444

The affected parts of the Central Arctic are now displaying temperatures around zero degrees Celsius.

I'm wondering, is all the ice below now at close to that temperature, all the way down to the water below at around -2 degrees? (The buoys should tell us that. What do they say?) Has enough latent heat been added that all this region will stay at around zero degrees surface air temperatures for the rest of the melt season, except maybe even heating up a little bit more at the ocean's surface where the ice melts out?


If so then all this region appears ripe for melt pond formation, and then serious melting whenever the sun is shining down around the next couple of months.

So maybe the Central Arctic is primed for a big melt season? And is this earlier than in previous recent years?

So very interesting but a lot of assumptions and speculation on my part.

What do others think? Is this usual? Or is this earlier than usual? And is it setting us up for a potential big, or even record, melt out this season?


 :o


EDIT:
Now looking at the Central Arctic temperature map...
http://ocean.dmi.dk/arctic/meant80n.uk.php
Note that 2012 rose to 0 degrees C earlier than is typical but 2013 & 2014 were both later. Was this a relevant factor in the big 2012 melt and in the suppressed melts of the past 2 years?
(I realise the temperature weighting has been done wrongly for this graph, so it is weighted too heavily around the North Pole rather than being a true average - which would be more probative.)

Will be very interesting to see when this plot hits 0 degrees this year. I'm guessing it will be early again. And this will give a bigger time window of opportunity for melt ponding & fast heat absorbtion.





579
Do you really mean just 1000 km^2?
Isn't the conventional definition of 'functionally ice-free' set at  1,000,000 km^2?

580
Arctic sea ice / Re: The 2015 melting season
« on: May 25, 2015, 05:22:28 AM »
@slow wing - I have only played around with the nullschool datasets I do not know the specific correlation to cloudcover or precipitation events.  I don't think that you can extract the level of detail regarding precipitation using it unless it is absolutely obvious (i.e. 25C and 100% humidity is most likely rain!).  For cloud cover if you go to NASA worldview, MODIS can show a rough correlation to cloud cover, I like to work with the 1000 hPa elevation for the arctic and TPW for cloud cover, it correlates, well, ok I guess.

compare

http://earth.nullschool.net/#2015/05/21/1200Z/wind/isobaric/1000hPa/overlay=total_precipitable_water/equirectangular=-69.88,87.24,1193

https://earthdata.nasa.gov/labs/worldview/?p=arctic&l=MODIS_Aqua_CorrectedReflectance_TrueColor%28hidden%29,MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels%28hidden%29,Reference_Features%28hidden%29,Coastlines&t=2015-05-22&v=-6553600,-3231744,6553600,3231744

click on earth and select arctic (top right)
then on left click "corrected reflectance 3-6-7
and you can see if they match up very well.  ..
Thanks for the info, Jai, much appreciated!

581
Arctic sea ice / Re: 2015 sea ice area and extent data
« on: May 22, 2015, 11:32:43 AM »
These maps are great, thanks Wipneus!

The Arctic basin just inside the Bering Strait has been blasted for several days with ~30 kph winds at just above freezing, so it makes sense to see melt ponds there in the last frame.

582
Arctic sea ice / Re: The 2015 melting season
« on: May 22, 2015, 05:56:19 AM »
...http://earth.nullschool.net/#2015/05/21/1800Z/wind/isobaric/1000hPa/overlay=total_precipitable_water/equirectangular=-149.88,69.80,1306
You seem knowledgeable on these marvellous nullschool maps.

If you would be so kind as to help me out, is this "total precipitable water" overlay the best one for estimating cloud cover vs if the sun is shining on the ice? For example:
http://earth.nullschool.net/#current/wind/surface/level/overlay=total_precipitable_water/orthographic=-35.44,93.43,1444

(I looked at http://earth.nullschool.net/about.html and also tried "total_cloud_water" as an overlay but it didn't work.)

Also want to know if it is raining/snowing.
So "temp" overlay would suggest rain rather than snow for T~>0?
And then the "relative_humidity" overlay would need to be close to 100%? But then how to distinguish rain from fog?

Any tips would be appreciated, thanks.



583
Arctic sea ice / Re: The 2015 melting season
« on: May 21, 2015, 07:05:43 AM »
So have the weather models backed off on that heat wave spanning much of the central Arctic basin?

Have been watching the Nullschool temperature map...
http://earth.nullschool.net/#current/wind/surface/level/overlay=temp/orthographic=-35.44,93.43,1444

The Beaufort has been above 0 degrees C over the past few days but that hasn't developed much over the past two days. Likewise, there hasn't been much of a high temperature incursion from the Atlantic side.

So interested to see what the weather models are predicting now, if anyone would be nice enough to post that, thanks.

584
Arctic sea ice / Re: May melt ponds do not matter
« on: May 21, 2015, 06:59:16 AM »
Wouldn't a powerful tool be to study the local correlation between melt pond formation & melt-out where the ponds have formed?

A large positive correlation might be expected.

This could then lead to region-specific predictive modelling for each melt season.

585
Policy and solutions / Re: Renewables Reach a Tipping Point...
« on: May 17, 2015, 03:39:39 AM »
I don't understand that. The swept area looks tiny compared to current wind turbines of the same height.

So they are relying on turbulence and eddy currents to collect the wind energy from a much larger area than the swept area?

Need further convincing. For the moment not optimistic about the commercial prospects for this design.

586
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: May 11, 2015, 04:02:10 AM »
Good call, John! The dark band doesn't appear to drift with the ice, so supporting the hypothesis it is associated with the geography of the sea bed. Fascinating!

587
Arctic sea ice / Re: The 2015 melting season
« on: May 04, 2015, 10:08:47 AM »
Wouldn't DMI 80N depend largely on wind direction?

For example, if there is a dipole setup with wind blowing ice out the Fram Strait then that means a high pressure system somewhere around Greenland and so that air came into the Arctic via Northern Canada and it will generally be COLDER.

Conversely, wind blowing in through the Fram Strait will be WARMER.

That's my intuitive guess. Does it make sense or are other factors more important around this time of year?

It will presumably be different later in the melt season, where surely the air will be warmer when there is little cloud cover and the sun is shining down on the ice?

What data is available to test these hypotheses?

588
Arctic sea ice / Re: The 2015 melting season
« on: April 21, 2015, 01:56:41 PM »
Very interesting discussion. It would be nice if we can identify the source of this effect.

Another thought I had was does this correlate at all with cloud cover?

589
Arctic sea ice / Re: The 2015 melting season
« on: April 20, 2015, 02:54:06 PM »
Ah, thanks, so it is newly installed. That might explain the temperature profiles.

590
Arctic sea ice / Re: The 2015 melting season
« on: April 20, 2015, 02:42:48 PM »
But what about the readings 4 days earlier?

Maybe it was floating and has just been placed back on the ice???

EDIT:
How do you interpret that?

Maybe down to sensor 5 is snow and on 16th April the ice was all about ready to melt, in temperature equilibrium with the -2 degrees water, but then cooled by 20th April?

591
Arctic sea ice / Re: The 2015 melting season
« on: April 20, 2015, 02:34:40 PM »
Wow! That's averaging nearly 3-1/2 km/h.

 Do its sensors show it to still be on ice or is it just floating in the water?

EDIT: I clicked on the buoy link and it is still on ice. Must be a strong wind doing that then?

EDIT2: wait, what is going on with the sensors? On 16 April, sensor 5 and  higher appear to be in water. Four days later it looks like on ice down to sensor 20.

Explanation?

592
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: April 20, 2015, 11:03:40 AM »
OK, very interesting! Thanks Wipneus

593
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: April 20, 2015, 09:21:25 AM »
Very interesting plot as always, thanks Wipneus. But can ice really 'torch' that quickly? Must be dispersion, no?

594
Arctic sea ice / Re: Piomas vs. CryoSat
« on: April 18, 2015, 12:58:30 PM »
Thanks to CryoSat for this new offering. Really interesting!

595
Arctic sea ice / Re: The 2015 melting season
« on: April 17, 2015, 07:05:48 AM »
On a more positive note: crandles and others, I've solved the temperature vs anomalies dilemma on the new ASIG Forecasts page! I've made a second, identical Forecasts page with the actual SATs, and via small links you can switch between actual temps and temp anomalies.

Pretty elegant solution, if I say so myself. Must be because I spent time with actual scientists at AGU today.  ;)

Nice  :)
That page is awesome! Thanks, Neven.

EDIT: the whole site is awesome actually! You've done a lot of work on it since a few months ago?

596
Arctic sea ice / Re: The 2015 melting season
« on: April 17, 2015, 07:02:52 AM »
I wish they would do those diagrams in million Km^2 instead of % of ice because proportion could give impression of recovery when area is actually declining.

Quite so. And what about the volume?  ;)
Thanks for these comments. Was thinking the exact same thing.

597
Arctic sea ice / Re: The 2015 melting season
« on: April 15, 2015, 10:45:54 PM »
If you'd like a more up to date video for your forthcoming article on the subject let me know. Here's one I somewhat hastily prepared earlier:



You could speed it up slightly, but that's a very nice animation, Jim. It's fascinating to focus on just one area (Beaufort, North Pole, Kara/Barentsz) and see how the ice moved in these past couple of months.
Yes, that's a fascinating animation. Thanks Jim, much appreciated

598
Arctic sea ice / Re: The 2015 melting season
« on: April 14, 2015, 02:32:07 PM »
 That temperature is only at 2 metres, so isn't that around the temperature of the top of the ice as  well?

  If I'm understanding correctly, there is no reason for the top of the ice to be at 0 degrees. Around -2 degrees is the temperature of the bottom of the ice that is in contact with water. The top of the ice is in contact with the air and so sets the air temperature. Would the temperature of the top of the ice at this time of year mainly be determined by the boundary conditions of thermal long wave radiation into a cold sky and a thermal gradient to the bottom of the ice at -2 degrees, with the rate of heat flow upwards determined by the ice's thermal conductivity? The air itself has little thermal mass density and so won't much affect the temperature at the top of the ice - it's more the other way around, with the ice temperature mainly setting the air temperature.

  Is that how it is?

599
Arctic sea ice / Re: The 2015 melting season
« on: April 03, 2015, 04:35:44 AM »
Thanks Rubikscube, great plots!


Much of the reason for a low maximum area this season is the relative depletion of ice in the Sea of Okhotsk.

Clearly this anomaly is going to have little or no effect on the ice area minimum in the Central Arctic at the end of the melt season.

So the low maximum area  doesn't in itself suggest a low minimum.

Am I correct though that there are suggestions of widespread positive temperature anomalies in the Arctic water? Can anyone confirm or put me right? If so, would this be expected, or not, to result in more melting on the timescale of the length of the melt season? Big effect? Small effect? Thanks.

600
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: April 01, 2015, 10:06:06 AM »
It's the son of the goat from seasons past!  :o

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