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Mary A Bein

Nares Strait in the Arctic, Pine Island Glacier in the Antarctic calving a berg that's huge. We are so used to seeing just how low we can go; I for one would like to see a slowing of the momentum of ice melt. I found this blog from a commenter at Daily Kos in August, 2012 and have a great respect for all who contribute here.

fryingpan136

Welcome Mary. I too found this site via Daily Kos.

Tor Bejnar

No ice bridge formed after the 2006 melting season, per the referenced NASA-led study, so 2007 had 12 months of transport through Nares Strait. Most years (i.e., the average) have about 184 days of blockage.

Although Arctic ice loss through the Nares Strait is much less than through Fram Strait, I give some credit to 2007's record ice loss to the unique event of no ice bridge.

A-Team

Here's an old Inuit trick for taking conditions at the Nares Strait and working that up into an Arctic-wide ice classification system.

Starting from the Modis above, the cloudfree Jaxa color microwave of the same date has better information, even though just a fraction of the resolution.

Averaging a 3x3 pixel sample provides a fiducial color. From that they would build a concentric set of nested microcubes about the fiducial color within the overall RGB false color cube.

Below, that is done in ten stages of incrementing the radius by five, coloring in the ice at each stage with a cooling spectral palette.

You can see from considering other lines of evidence that this works quite well. Note open water and core multi-year ice do not end up being colored by this procedure.

Image is 536 pixels wide:
 photo nares_zps0fece965.jpg

Apocalypse4Real

A-team that is terrific.

I am presuming that the brownish is open water and the white is more solid, unbroken or MYI.

Can you give us a breakdown of what the color ranges represent? For example, are reds 15-25% sea ice concentration?

I do not know how hard this was to generate, but for me this image is a much easier read that the U Bremen.

Kate

What does this do to the glaciers feeding into this area? Does it speed up glacial transport?

Robertscribbler.wordpress.com

Warmer waters in the vicinity would speed transport of glaciers that contact the tidal area.

The biggest effect, as Neven points out, is the impact on thick ice just North of Greenland and the CAA. Gives warmer waters another avenue through which to erode the thick ice even as it provides another ice passage out of the CAB.

Robertscribbler.wordpress.com

... That said, some of those channels do go very deep into the Greenland ice sheet. So it's definitely something to watch if ice free/warmer conditions come to dominate this region for longer periods.

A-Team

A4R, yes, in the animation above, the brownish is open water and the white is more or less MYI. These do not directly correspond to sea ice concentrations but represent nested melt stages, microwave emission properties increasingly less and less like the fiducial area in the Nares Strait.

Successive colors are then a prediction of melt-out order. The number of pixels of each color, divided by the number in the whole Arctic Basin, would give approximate relative areas. (I needed to have included a land mask at the start.)

Below, I did a variation of this principle, here selecting the open water only. The main idea here is a color image has 256 * 256 * 256 = 16 million RGB colors, a lot.

It took three fiducial colors to pick out the open water satisfactorily (brownish, yellowish wind waves, clouds over water). These three boxes needed to be about 20 pixels in radius, so 3 * 20 * 20 *20 = 24 kpixels for the boxes, which are disjoint and together occupy only a tiny part -- 0.14% -- of the overall color space.

This is why we want all our satellite base images provided in grayscale -- to make an RGB false color imagary which offer far more discriminatory capacities.

The animation below shows the three pure colors used as the selection box centers, the daily percent open water area in the Arctic Basin as masked, and the overall fitted rate of open water formation (1.6% per week).

 photo openWater2_zps6cd3039d.gif

A-Team

Here is a new development, across the pond from Nares Strait. The ice pack has begun rotating again in the last few days, this time clockwise.

A portion of the open floe area left over from the persistant cyclone near Severnaya Zemlya is expanding rapidly and may result in a continuous swath of open water between the Laptev and Franz Josef Land.

The image juxataposes a wikipedia map roughly rescaled to the 15 July 13 Jaxa color microwave.

 photo severnyaZem_zps842aa76f.png

A-Team

I registered for this webinar tomorrow Tuesday July 16th at 10 a.m. EDT by the director of NSIDC, Mark C. Serreze. Note it will be archived online as well.

"Arctic summers could be ice-free as early as 2030," said Dr. Mark C. Serreze, director of the U.S. National Snow and Ice Data Center (NSIDC - part of the Cooperative Institute for Research in Environmental Sciences based at the University of Colorado in Boulder)

In the session "Environmental Impacts of the Arctic's Shrinking Sea-Ice Cover" he will examine the social and economic effects of the retreat of the Arctic Ice Cap and the opening of the Arctic Ocean.  Registrationis open to everyone free of charge.

Ice-free summers by 2030? Hmmm, could be a case of walking back old predictions using a helpful definition of full summer (astronomical or meteorological). Sounds like a couple of ice-free months wouldn't cut it.

For me it would -- indeed, why not just set the bar at the year of (essentially) all first-year ice.

Or something directly relevant to downstream climate change -- say heat budget or jet stream effects, say when the integral of daily albedo * daily insolation falls 50% or more below 1979-81.

With the Calypso radiometer now measuring both upwelling and downwelling radiation over the whole Arctic Ocean, clouds and feedback mechanisms acting on them can be accommodated too.


Charles Longway

A-Team,
Thanks for the animation– beyond excellent. I hope that you can extend the animation for the rest of the season. I take the blue swirls over the ice to be clouds. If so, it would be nice to get the clouds over water to also be blue swirls. I can see the clockwise rotation you mentioned very well. Is the lack of rotation on the Greenland side indicative of compression?
Regarding your “open channel” near Sevemaya Zemlya - The situation reminds me of the chunks that came loose last year in the Laptiv Sea late in the melt season. This year, with the weakness in the center, could we see larger breakaways, or even the center fracture and open? This fragmentation reminds me of how the Western Antarctic melts. If we see breakaways, as in your conjecture, then the average ice latitude may be further south, and keep extent dropping quickly for another month.
On the general topic of export, I have been watching the channels in the CAA other than Nares on Hycom:

http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn_nowcast_anim30d.gif

The animation suggests that export is happening on the western two channels. Is this real or just my fear? It looks like a lot of MYI is being exported towards the NW passage.

Craig Merry

Thanks for the link and the amazing animation A-Team.

2030 is still a very liberal "ice-free" metric from a scientist- I think if you asked most people studying the ice in some way as a scientist they'd probably say 2020. 2030 is a an amazing number considering if you were looking at projections from 2006, even 2010.

George Phillies

For those of us not expert in photographic reconnaissance, is there a current update on the scenic Nares Strait?

John Christensen

George, DMI has great satellite images around Greenland:

http://ocean.dmi.dk/arctic/kane.uk.php

A-Team

I have a sneaking suspicion that neither we -- or anybody else -- is making anywhere near full use of all the satellite channels currently observing the Arctic Ocean. That is not so much the case however for Nares Strait or the Petermann Glacier feeding into it. The latter is intensively instrumented and studied with high resolution Modis and flyovers for breakup and calving.

As an experiment, I took all the microwave channels from Suzaku (except 89 Ghz, a much-utilized special case) and changed the palette from thermal to grayscale (and a bluer tint at higher frequencies) and then made various RGB color images from different triples of grayscales.

It's feasible to make all 14! / 11! * 3! = 364 images though the animation just contains a sampler. (R, G, B can be shuffled later for viewing aesthetics.)

That search process could be short-circuited by determining channel correlations first and principle component analysis of the whole set to find a 3-4 channel informational optimum, folding in clouds and the time series of the preceding week.

This has been done on land imagery for decades; it's not clear why it is not offered somewhere online as a canned product for the Arctic.

 photo multiPal_zps782dafd6.gif

jdallen_wa

A-Team: you wicked person ;)

I now have a new data addiction because of you. I had no idea this was here, and yes, there is a huge trove of un utilized information here.

Less flippantly, there's a lot here which may be able to filter out conditions and isolate what we are attempting to measure. What sort of resolution does this have? There a link to where the metadata is described?

A-Team

Jd, no question there is a lot more we could be doing here-- it really would take a group effort to fully explore this and the Modis data troves.

This is a large satellite center web site full of launch videos, mission statements, instrument innards etc etc -- I just cut to the imagery and work backwards from there.

It would be good in this case to chase down the metadata and numerical ur-data (pre-rasterized) because their 'display' image archive doesn't include the all-important grayscale or provide ftp downloading (which adds up quickly manually at 28 wavelengths, polarizations, and orbit limbs per day).

The ground resolution is ok but not exceptional -- the Arctic Basin about fills the 400-pixel width limit of typepad. The 89 Ghz is twice that and it seems to have two separate antennas -- I couldn't find an explanation for that nor the rationale for the overall selection of wavelengths.

Here is a rather suggestive image for 16 Jul 13 with (R,G,B) = (06 hor asc, 23 hor asc, 36 vert, asc) made just from discarding the hues and saturations. It seems to capture the melt and maybe predict the about-to-melt succession, as well as locate thicker multi-year ice.

This particular date did not have a cloud issue -- more generally, a ten day time series helps determine (from motion) what effect, if any, clouds are having on the image.

Descending limb has a smaller blackout at the pole and I will animate that to get at ice class time trajectories.

 photo novelColor_zps770eff20.jpg

A-Team

The animation below continues experiments with combining passive microwave emissions at 3 wavelengths into a false color image.

It takes horizontally polarized 6, 23 and 36 Ghz channels from the descending orbit limb of AMSR2 as the RGB channels for the first 17 days of July.

This produces an overly complex series of images in which the growth of open water areas is most easily interpretable.

The still image above from the ascending limb suggests that might be more favorable to animate.

However, to explore all 364 combinations of channels with a 17 day animation of 3 channels would require 18,564 image downloads; neither the satellite center or Gimp is really set up for automating the process.

Better to find some way of first zooming in to only the most informative subspace of channel combinations.

 photo 062336July_zps3452c2a0.gif

MaGa

Hi A-Team!

For automatic downloading, you might want to have a look at wget:

https://en.wikipedia.org/wiki/Wget

Werther

That’s (post 01:05) an interesting image, A-team!
When I compared it to day 198 MODIS, I pick up some indications…
One is, that the recent high may be responsible for tearing the MYI “mesh-pack” apart at an axis through tile r04c03 Laptev – McClure Strait. This clump of about 300K is losing contact with the main body N of Ellesmere (1.300K). At the same time, the late winter 1,800K safe-haven of structured pack is intruded by structure loss 600km from the Pole in the middle of r04c03.

There is a ‘brown’ arm connecting the Beaufort clump to the ESAS. As there’s no way that could have formed through export of remaining MYI, I suggest it is compacted FYI due to the June PAC.

Your graph reveals two potential ‘flash-melt’ regions. One is the Beaufort-Chukchi region, about 950K.
The other is the Barentsz-Laptev region, 1.700K.
A 180K fast ice clump in the Laptev-ESAS coastal zone is bound to go.
So, as there’s 6Mkm2 area / 8Mkm2 extent, now, pinch hitter weather could easily reduce that to 2012 levels in the weeks to come.

A-Team

MaGa, excellent idea. I see they have GWget as a firefox browser extension, FireGet.

That is only the half of it unfortunately -- Gimp is not well thought out for animation (ie operations should have an option act on all layers) or scripting, though G'mic in theory could do all that, or the Gimp Animation Program augmentation (really intended for windows); massive downloads beyond my internet connection and beta software raising myriad issues elsewhere on the system.

Resolvable, but meanwhile the ice will have all melted.

I've just located two very useful gimp commands -- in the wrong menus like so many of them -- that resolve the issue of synchronizing animations to the same date. That would be Filters -> Combine -> FilmStrip... and Image -> Transform -> Guillotine. In FilmStrip, de-check everything in the Selection tab. In the Advanced tab, set Image height to 1.0 and zero out everything else. This will butt out every selected window (and every selected layer within them) end to end in a horizontal film strip. Next vertical guides need to placed where you want so Guillotine will slice it up correctly into separate files (to be reassembled into a single image with layers). For example, for 20 frames, set guides at 5% intervals. If you had remembered to turn everything sideways initially, turning the output 90º CW will orient it correctly again at Typepad's 400 pixel width.

Navy Hycom looks to me like it has gone badly off the rails on thickness off the New Siberian Islands. All their end-user displays are ultimately based on satellite images -- which channels has always been a bit baffling, especially for thickness. However it is feasible to compare it to the last ten days of each of microwave channel, so 8 animations with enforced synchronization coming your way.

Werther, you've been looking at the ice for a long time and have developed some very interesting insights. Today 18 Jul 13 had really extraordinary visibility -- Jaxa color is below, shades of magenta showing the next areas of ice to melt.

 photo 18Jul13b_zps9bd991cc.png

A-Team

In another five days, our main satellite resourse AMSR2 will first begin to provide same day comparisons of 2012 to 2013.

 photo 201213Comp_zps4bd65fbd.gif

 photo 19July13jaxaB_zpsddb7220b.png

John Christensen

I am looking at the DMI satellite images for Nares Strait, with 'Kennedy' for nothern part and 'Kane' for the southern part of the strait:

http://ocean.dmi.dk/arctic/kennedy.uk.php
http://ocean.dmi.dk/arctic/kane.uk.php

The bridge at the southern end has collapsed and was preceeded by in situ melting, as commented by Neven in the intro. However, the ice also seems to be blocked at the northern end, so does not seem like flow would pick up before this piece of ice breaks up?

me.yahoo.com/a/nSjChi4X3vr8X3DRw93GkY1.cerja.8nvWk-

For those of us not expert in photographic reconnaissance, is there a current update on the scenic Nares Strait?

Here's a shot from MODIS from yesterday, showing the break up near the mouth of the Petermann glacier, looks like it will break-up over the next couple of days.

http://i302.photobucket.com/albums/nn107/Sprintstar400/Nares.jpg

Neven

My experience with Nares Strait is that as soon as the arch breaks up, everything is on the move within two weeks. This year seems quicker, because the arch broke up quite late.

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