The 2017 melting season

[greatdying2]

I've responded here to keep this thread on topic.

Your link is broken. Here is one that works: http://forum.arctic-sea-ice.net/index.php/topic,143.msg123369.html#msg123369 .

[greatdying2]

In the absence of recent above ice pictures, the thermistor string and (rather noisy) sounders on 2017A  suggest that the remaining ice near the buoy is now around 20 cm thick:

What is the unit of the x-axis, cm? Am I misreading it, or is the current thickness at a bit less than 10 (whatever units)?

[greatdying2]

This has an uncertain effect over the quality of the sea ice as it insulates the ice from the bitter cold of the polar night, reducing thickening while simultaneously delaying melt due to higher albedo.

Never the less, we entered this melt season with sea ice in a condition never before witnessed, lowest max volume recorded and thinner than ever. Over the past decade, the sea ice has been pulverized into small floes and is more mobile as well.

It seems like you answered your own question? We are just now getting to the late season, when we will see whether unusual ice thinness outweighs unusual snow thickness. (It seems one might already conclude that big drops still remain weather-dependent, so at least there's still some hope that the ice may last another decade.)

[Deeenngee]

Here's my minimum extent (IJIS) chart that's equivalent to the one I put up for the maximum, i.e. picking out the moment of minimum extent for each year since 1990.

For this first one I've kept the lines showing for each year, just so you can see that I haven't just plotted each year's minimum at some random location! I didn't do this by eye of course; on the IJIS datasheet it's easy, using conditional formatting, to highlight the lowest number for each column (year). This shows you the day number (i.e. date) of the minimum, which is then fairly easy to find on each line. Then right click, format data point, marker options etc etc.

What striking is how bunched the minimum dates are across the years, compared to the maximum (2nd chart below). Any ideas why, anyone?

And here's 2017 appearing, audience left / stage right....

[VeliAlbertKallio]

I go for sunlight reflection from the water of the open sea. If it were methane eruption, the fire could also be seen over the land (and we would have heard of it in media). If it were aurora borealis, it would be above clouds, not under them. Forest fires occur on land, not over sea.

Has anyone any idea of what these pictures show ?

These were extracted from:

...
I attached AVHRR Imagery to show the clouds.
http://weather.gc.ca/satellite/satellite_anim_e.html?sat=hrpt&area=dfo&type=nir

http://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=382.0;attach=49261

[greatdying2]

Forest fires occur on land, not over sea.

... and let's hope it remains that way... 

[Jim Hunt]

What is the unit of the x-axis, cm?

It's thermistor number. They are nominally 10 cm apart. A more detailed explanation can be found at:

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/

[greatdying2]

It's thermistor number. They are nominally 10 cm apart. A more detailed explanation can be found at:

Ah, thanks. So it's the length of the steep part of the curve (between air and water -- in the case of the July 30 curve, approximately thermistor 9 to 10 plus some on each side) that matters, not it's placement. Sorry for the OT; I should have put this in stupid questions.

[subgeometer]

Some of the remaining high concentration ice in the Beaufort Sea. It looks very fragile nevertheless

[sedziobs]

What striking is how bunched the minimum dates are across the years, compared to the maximum (2nd chart below). Any ideas why, anyone?

I would say it is largely due to the fact that the winter maximum is spread among many different basins, each at differing latitudes and with varying heat fluxes.  The minimum is generally confined to the central basin.

Musings on the wide spread of winter maximums can be found in DavidR's The Plateau Hypothesis thread.

[Apia]

Here's my minimum extent (IJIS) chart that's equivalent to the one I put up for the maximum, i.e. picking out the moment of minimum extent for each year since 1990.
...
What striking is how bunched the minimum dates are across the years, compared to the maximum (2nd chart below). Any ideas why, anyone?

IMO, the minimum are grouped tightly because the counter-trend that stops the melt is bound to a very stable feature; the night lenght grows, the day shorthens.  So its very difficult to change the time when the ice start to grow back, but for the case of very hot sea water or a tectonic event.

On the other hand, the ASi max depends on many factors and the spring sun heat is not that strong compared to the other factors; Atlantic drift/Gulf stream, snow cover, the hot layer under the ice, the "final" temperature of the ice itself... 

So, i believe the Arctic night is much more powerfull than the oblic spring sun + the ice is insulated by the snow in spring and have no insulation in Septembre.  That's my guess.  I feel there is also something linked to the ease to radiate the heat back in space, but I cannot gather my toughts properly on that one.

[Apia]

Forest fires occur on land, not over sea.

... and let's hope it remains that way... 

Thanks guys, i was about to err...  So, let's move on.

[greatdying2]

The weather continues to look bad for the ice on the Pacific side, right where it is weakest. (NB: I don't think that's a coincidence -- positive feedback...) Here is the forecast pressure, wind, and waves 2 days out.

Also, it's quite clear today -- have a look at WorldView. Pacific and Russian sides both look very weak.

[polynya]

"Swan song" for the arctic ice?

(inexperienced and not sure image will show correctly)

[romett1]

Also, it's quite clear today -- have a look at WorldView. Pacific and Russian sides both look very weak.

Agree, just created animation - Aug 2 vs July 30. Images: ftp://ftp-projects.cen.uni-hamburg.de/seaice/AMSR2/

[greatdying2]

Nice animation and quite a change! One can almost imagine a line is showing where the ice edge might end up.

On a similar note, I have noticed that occasionally someone posts a merged image of the Bremen (I think?) visual colour map, where the darkest pixel has been chosen over several days to help remove cloud effects. I like these very much, but personally I prefer the NIC colour images for their improved contrast. So I wrote a program to do a similar merge on these, where the lowest ice concentration is shown for each pixel. So far I have only generated one for the last 3 days of July, which is attached along with the original images.

Note: this is beta so if anyone notices any errors, please do let me know.

[DavidR]

According to the NOAA ESRL data released today July was the second hottest July on record, after 2016, globally. 2017 is still second warmest on record in the Arctic for the YTD.
 https://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl

However in the Arctic July wasn't in the top 20 years. Over the past three months the Arctic average wasn't even in  the top 25 years. 

This lack of heat over the past three months gives us an indication of just how weak the ice must have been at the start of the melt season to still be in contention for the lowest three values.

[Rob Dekker]

A few days ago, I suggested that since ice concentration was running very high (2013/2014 levels),  that 'extent' was about to 'stall' since typically 'area' is a better indicator of actual ice melt, and 'area' has been running quite high for some time.

Only to get slapped around the ears with two century breaks in 'area' and a double century break in 'extent', while the only thing of significance that could have caused that is a mild storm on the Pacific side. One that 'normally' should actually cool down things, and cause some dispersion.

The only reasonable explanation for these century breaks seems to be that (as many of us have pointed out before) that the ice in 2017 is simply thinner and thus more sensitive than in prior years, just like PIOMAS told us all along. It's just that the effect of that thinner ice is really starting to show up now at the end of the melting season.

High ice concentration (and 'area') were at the core of my 'high' projection, and I'm starting to feel a bit concerned now that we may see a lot more ice disappear rather than preserved before the end of the season....

[greatdying2]

Wow...

[Geoff]

Nice animation and quite a change! One can almost imagine a line is showing where the ice edge might end up.

On a similar note, I have noticed that occasionally someone posts a merged image of the Bremen (I think?) visual colour map, where the darkest pixel has been chosen over several days to help remove cloud effects. I like these very much, but personally I prefer the NIC colour images for their improved contrast. So I wrote a program to do a similar merge on these, where the lowest ice concentration is shown for each pixel. So far I have only generated one for the last 3 days of July, which is attached along with the original images.

Note: this is beta so if anyone notices any errors, please do let me know.

I was playing around with it at one stage - One warning about using the darkest pixel & using NIC, is that the colours are made up of RGB, so choosing the 'darkest' may not actually be accurate - Purple will have high red and blue but low green, but the greens and yellows will have high green and red but low blue, respectively. Is [1,0,0] brighter than [0,1,0]?. I think it may work better on the white to black RGB maps, unless you have a way to detect which colour is meant to be darker than the rest.

[greatdying2]

One warning about using the darkest pixel & using NIC, is that the colours are made up of RGB, so choosing the 'darkest' may not actually be accurate...

You're right and I don't think there's a simple way like that to do it. What I've done is to convert each pixel to a concentration value using the colours provided in the key, take the minimum concentration, then map it back to the colour.

Here is the 3-day minimum map ending today. (Actually today is so bad that you have to look pretty hard to find areas that were worse on the previous 2 days.)

Soon I plan to make a movie of these -- I think it would be quite informative. Anyways it would be much better than flipping between browser tabs and squinting hard to mentally eliminate clouds. 

[Geoff]

One warning about using the darkest pixel & using NIC, is that the colours are made up of RGB, so choosing the 'darkest' may not actually be accurate...

You're right and I don't think there's a simple way like that to do it. What I've done is to convert each pixel to a concentration value using the colours provided in the key, take the minimum concentration, then map it back to the colour.

Here is the 3-day minimum map ending today. (Actually today is so bad that you have to look pretty hard to find areas that were worse on the previous 2 days.)

Soon I plan to make a movie of these -- I think it would be quite informative. Anyways it would be much better than flipping between browser tabs and squinting hard to mentally eliminate clouds. 

Sounds good, one other warning - you might be using the lightest pixel in your algorithm by mistake - that gash to the sw of the Pole is only present in today's image, so it shouldn't be showing up in your merged image... 

[jai mitchell]

Only to get slapped around the ears with two century breaks in 'area' and a double century break in 'extent', while the only thing of significance that could have caused that is a mild storm on the Pacific side. One that 'normally' should actually cool down things, and cause some dispersion.

I have not looked at it directly but believe that there may be some significant contribution from West Greenland and Hudson Bay as well.  The SIE values are northern hemisphere and include all visible sea ice.

[Rob Dekker]

What I've done is to convert each pixel to a concentration value using the colours provided in the key, take the minimum concentration, then map it back to the colour.

Sometimes clouds create virtual 'low' concentration pixels, so you may actually be amplifying cloud effects in your program. Like that patch SW of the NP in your latest image.

That said, I'm surprised that your three-day algorithm finds most of the low concentration ice in the ice margin, where we would expect it.

Nice work !

[Rob Dekker]

I have not looked at it directly but believe that there may be some significant contribution from West Greenland and Hudson Bay as well.  The SIE values are northern hemisphere and include all visible sea ice.

Fair point, Jai.
Wipneus noted in the "sea ice area and extent" thread, regarding the double-century drop :

extent drop is big and is mainly within the Basin. Ice in the Beaufort, Chukchi, CAB border region is getting a beating from a storm,

So it looks like the main action is indeed from the CAB and surrounding seas.

[greatdying2]

you might be using the lightest pixel

Yes that's exactly what I'm doing, but it's on purpose. Each pixel shows the lowest concentration over 3 days. The idea is to eliminate the falsely high concentration regions caused by clouds. (However, it also means that when the ice moves, lower concentration regions "overwrite" higher concentration ones -- so interpret accordingly...)

Sometimes clouds create virtual 'low' concentration pixels, so you may actually be amplifying cloud effects in your program. Like that patch SW of the NP in your latest image.

That said, I'm surprised that your three-day algorithm finds most of the low concentration ice in the ice margin, where we would expect it.

Nice work !

Thanks, and I'll keep that in mind. (Hopefully most artifacts will become apparent in movie format.)

[Thawing Thunder]

On a similar note, I have noticed that occasionally someone posts a merged image of the Bremen (I think?) visual colour map, where the darkest pixel has been chosen over several days to help remove cloud effects.

Hello GD2, I think that was me. I did exactly that last year, first manually and then, in the later versions, with the color picker in Photoshop (not the darkest pixels though, but the brighter green, yellow and red ones). This year I changed to the Hamburg map, which I feel has a stronger visual impact (especially if you push the contrast à la Wipneus), I posted my last result yesterday as a gif-animation. I think it's helpful if you want tho get a view of the whole picture, between three images lay just 48 hours, so in most weather conditions the drift is not so strong, and clouds move faster anyway. Great that you are contributing something similar, a single image says more than a thousand words!

[deconstruct]

Yes that's exactly what I'm doing, but it's on purpose. Each pixel shows the lowest concentration over 3 days. The idea is to eliminate the falsely high concentration regions caused by clouds.

...but at the same time introducing other false values, because every ice movement will decrease concentration in your image, regardless of the real situation.

And as Rob pointed out: Clouds are not always responsible for higher concentration pixels, but also for lower. So I am not convinced, that this 3-day-composite, that amplifies just low concentration pixels, is anywhere nearer at reality, than the original images in the first place.

[seaice.de]

I really like the running-minimum sea ice concentration filter, it seems to be a quite reasonable approach to suppress the impact of clouds and water vapour. The ASI 89 GHz algorithm is quite sensitive to the atmosphere and mostly reacts with an overestimation of ice concentration when there are clouds (due to the scattering which decreases polarization). And it is reasonable because the atmosphere moves much faster than the ice.

So please go on with this kind of post processing, it seems to give useful and reasonable results!

[greatdying2]

Yes, TT, it was you. Please post more of them.

I added this version because I like the colour contrast better, because I wanted an excuse to do some coding using ImageJ, because I want to make movies of them (which I think may be even more revealing), and because I have some other ideas of what to maybe do with this data later (something with classifiers and predicting the minimum). Oh and for fun 

Seaice.de, thanks for the encouragement. I have spent quite a bit of time over months and years "flipping and squinting" at these maps, and my observations bear out your statement that usually atmospheric disturbances (clouds, etc.) move quickly and cause dramatically increased apparent concentration. But "flipping and squinting" is annoying -- this way is much more pleasant.

Deconstruct, I do agree (as I said before): there are limitations, especially fast-moving ice. But by merging not too many days, maybe it isn't too much of a problem, most days.

[Thawing Thunder]

...but at the same time introducing other false values, because every ice movement will decrease concentration in your image, regardless of the real situation.

As I wrote several times, I'm conscious of that effect. But without pixel peeping I think these images contribute something useful.

... I am not convinced, that this 3-day-composite, that amplifies just low concentration pixels, is anywhere nearer at reality, than the original images in the first place.

They are certainly flawed – as are even highly scientifically manufactured images. But it shows a more overall picture that you otherwise would not obtain. As I could observe last year and this year, they are useful to see where the ice is going. Of course, you have to take these images with a grain of salt – as you do with every graph here, I suppose.

... because I want to make movies of them (which I think may be even more revealing) ...

With a running three-days composite? THAT IS A LOT OF WORK!!! But the result would be utterly pleasant, and it would somehow mask away the distortions caused by drift in the continuous over all movement!

[greatdying2]

... because I want to make movies of them (which I think may be even more revealing) ...

With a running three-days composite? THAT IS A LOT OF WORK!!! But the result would be utterly pleasant, and it would somehow mask away the distortions caused by drift in the continuous over all movement!

Not too much work left now. Generating the 3-day (or n-day) minimum maps is already automated. I wrote a program to do it -- that's how I made these maps. All I need to do now is generate one for each day (one more for-loop should do it) and then figure out how to join them together into a movie, which is easy I guess. And yes, I agree that artifacts such as fast moving ice should be revealed in a movie -- unless they manage to run quickly away for many days. 

[Thawing Thunder]

Not too much work left now. Generating the 3-day (or n-day) minimum maps is already automated. I wrote a program to do it -- that's how I made these maps.

I envy you computer guys!

All I need to do now is generate one for each day (one more for-loop should do it) and then figure out how to join them together into a movie, which is easy I guess.

Make a gif. You can make it online, there are free platforms and it's very easy. Or import the images in your favorite editing software for longer an higher resolution results. If your are creating a loop: Please let the last image stand a while longer. That provides orientation in a loop. Otherwise there is a continuous swirl that causes nausea ;-)

[F.Tnioli]

... I don't understand why we are not racing towards a record low in SIE.

You sure do, come on? Atlantic's relatively cold this year, for one. Late melt ponding due to higher than normal snow cover, for two. Much broken Jet Stream, which - for a change, - gives among other things the negative feedback of more clouds in the Arctic during summer solstice - for three. And there is possibly the fourth thing which perhaps cools things down more than the three above combined, but i don't feel fancy even mentioning it here and now. And it's still a low extent year.

Yes this has been a mild melt season, cloudy and cooler than normal and, yes, I believe that a warmer, moister climate regime is establishing itself over the polar region which results in higher precipitation and, given the temperatures, falls as snow more often than rain. This has an uncertain effect over the quality of the sea ice as it insulates the ice from the bitter cold of the polar night, reducing thickening while simultaneously delaying melt due to higher albedo.

Never the less, we entered this melt season with sea ice in a condition never before witnessed, lowest max volume recorded and thinner than ever. Over the past decade, the sea ice has been pulverized into small floes and is more mobile as well.

I get that you are drifting in serene certainty regarding the Arctic (both things stated and secrets held from those to dense to comprehend) but is it OK if I still don't understand how SIE is not plummeting to an all time, record shattering low? 

Who's dense now, eh. Was just figure of speech, wasn't it? I'm feeling dumb now, for sure. But, note that the thing i wasn't fancy to mention has nothing to do with you; it's my uncertainty about the thing which prevents me from discussing it. But if you'd have it on your mind as i do, - and some people do, - then you'd instantly recognize. Still, it's controversial, and i don't want to start that kind of debate...

[gerontocrat]

.... the thing i wasn't fancy to mention has nothing to do with you; it's my uncertainty about the thing which prevents me from discussing it. But if you'd have it on your mind as i do, - and some people do, - then you'd instantly recognize. Still, it's controversial, and i don't want to start that kind of debate...

Controversy is a big part of ASIF. Challenging the conventional wisdom is how science and just about everything progresses.
Do not be afraid of being uncertain. If I did that I would scarcely post anything.

Meanwhile, weatherforecast.com says that starting Saturday or Sunday the Arctic is going to get some high energy weather. I attach an image from next Tuesday - admittedly 5 days out.

[Thawing Thunder]

Sorry, if I'm interrupting the current discussion. Just posting an animation of the last two weeks with some slowmotion. In my opinion now you can see very well, what are clouds and what is SI. If the trend we see continues, the next two weeks could definitely wreck the ice.

[pauldry600]

There seems to be some sort of crab image forming in the Arctic

[Ninebelowzero]

There seems to be some sort of crab image forming in the Arctic

If it's an advanced case of pareidolia you have there "who ya gonna call?"

[Anne]

FSM!

[RikW]

Sorry, if I'm interrupting the current discussion. Just posting an animation of the last two weeks with some slowmotion. In my opinion now you can see very well, what are clouds and what is SI. If the trend we see continues, the next two weeks could definitely wreck the ice.

Is it just me of is everything outside the triangle canada ~135th longitude and 15th longitude looking to go poof in any moment?

[VeliAlbertKallio]

I think the explanation for all this mystery lies in:

(1) the increase in 3-dimensional water-sitting ice surface - due to pulverized sea ice mopping up heat extremely efficiently 

(2) the increased mobility of crushed sea ice + the increased mobility & (vertical/horizontal) mixing of sea water to facilitate a very fast transfer of thermal inertia of sea water into sea ice 

(3) the resultant sea ice honeycombing, fracturization, flushing and softening by winds/waves 

<snip> However in the Arctic July wasn't in the top 20 years. Over the past three months, the Arctic average wasn't even in the top 25 years. 

This lack of heat over the past three months gives us an indication of just how weak the ice must have been at the start of the melt season to still be in contention for the lowest three values.

[Thawing Thunder]

Is it just me of is everything outside the triangle canada ~135th longitude and 15th longitude looking to go poof in any moment?

I think so, too. But it's August. If all that had started just a week earlier, I would have called "doom!". But it didn't. let's wait and see.

[Shared Humanity]

Yes that's exactly what I'm doing, but it's on purpose. Each pixel shows the lowest concentration over 3 days. The idea is to eliminate the falsely high concentration regions caused by clouds.

...but at the same time introducing other false values, because every ice movement will decrease concentration in your image, regardless of the real situation.

And as Rob pointed out: Clouds are not always responsible for higher concentration pixels, but also for lower. So I am not convinced, that this 3-day-composite, that amplifies just low concentration pixels, is anywhere nearer at reality, than the original images in the first place.

Given how fractured and mobile the ice is, it may just be better to simply animate as the blinking on and off actually captures the state of the ice.

[Shared Humanity]

Controversy is a big part of ASIF. Challenging the conventional wisdom is how science and just about everything progresses.
Do not be afraid of being uncertain. If I did that I would scarcely post anything.

Could not agree more, any idea is worth posting and discussing. Also, uncertainty (as in I can't understand) was the whole point of my post.

[Thawing Thunder]

Given how fractured and mobile the ice is, it may just be better to simply animate as the blinking on and off actually captures the state of the ice.

The perfect solution would be a software with pixel tracking. No double count of pixels in still pictures anymore. That could provide a nearly lossless composite, even over several more days.

[Shared Humanity]

Sorry, if I'm interrupting the current discussion. Just posting an animation of the last two weeks with some slowmotion. In my opinion now you can see very well, what are clouds and what is SI. If the trend we see continues, the next two weeks could definitely wreck the ice.

Not an interruption. This animation goes to the very heart of this thread and it also suggests I could still see that all time record low SIE.

[Shared Humanity]

Sorry, if I'm interrupting the current discussion. Just posting an animation of the last two weeks with some slowmotion. In my opinion now you can see very well, what are clouds and what is SI. If the trend we see continues, the next two weeks could definitely wreck the ice.

Is it just me of is everything outside the triangle canada ~135th longitude and 15th longitude looking to go poof in any moment?

Not just you.

[F.Tnioli]

The Fourth Thing !!! Area 51 ? Lord Voldemor ?
I want to know !

Yeah, right.

Appreciate the humor, but let's spare everyone else the remaining extent, area and volume (measured in thousands cubic kilometers, probably ) of your and mine comedian powers, OK? I'll go on in a PM.

[magnamentis]

Wow...

i think the swan will be beheaded

[magnamentis]

Sorry, if I'm interrupting the current discussion. Just posting an animation of the last two weeks with some slowmotion. In my opinion now you can see very well, what are clouds and what is SI. If the trend we see continues, the next two weeks could definitely wreck the ice.

Is it just me of is everything outside the triangle canada ~135th longitude and 15th longitude looking to go poof in any moment?

certainly not just you doesn't necessarily happen but has been seen coming as a serious threat for quite some time by TT and others.

EDIT: as mentioned by SH, have seen it later only, sorry for the ninja post.