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Finally, a graph of Cryosat-2 data! I was beginning to think they'd never release it. I'm puzzled by the lack of spring and summer data, though; does anyone know the reason for that? Is there something about sunlight reflecting off of the ice that makes taking readings difficult (more microwave light emitted by the ice and water themselves, perhaps)?

Kevin McKinney

"I guess we keep an eye on PIOMAS, eh?"

Yes, I guess we do!

Thanks for this, Neven.

Andy Lee Robinson

Neven, I've made a 2D version of the Arctic Death spiral using PIOMAS data in radial form, connecting monthly averages to produce another vivid and digestibe picture of what is happening.

It screams all decline, and no tricks.

Starting to go viral on Twitter and Facebook now.


3D animated version in the works.

Otto Lehikoinen

Thanks, I guess PIOMAS is becoming mainstream.


And bear in mind one of the paper's comclusions is:
"The rate of decline in autumn ice volume that our data show (~800 km3 a-1) is 60% higher than the decline in the PIOMAS integration analysed [by Schweiger et al. (2011).] This is further evidence that the PIOMAS estimates of autumn volume loss are conservative."


Nice spirals Andy.


I know this is a PIOMAS thread and my comment is regarding SIA (I've posted it on the SIA thread below.) but there is very little activity on the SIA thread so I thought I would repost here. One caveat, I don't know much about the cryosphere, have been visiting here for about a year so bear with me.

Post below.......

I have been following the discussions here for about a year. I have also been traveling to the links to get some of the background information and data to try to understand these discussions.

I have some observations and questions. As new SIA mimumums are reached both for the entire cryosphere and individual seas and CAB, we then frequently see "record breaking recoveries" during the following freeze season. Looking at global warming denier sites (WUWT et. al.) they seem to always use this rapid rebound of SIA during the freeze season as evidence of the recovery of Arctic Ice as a whole. Obviously this is not the case. The rapid rebound is nothing more than evidence that water freezes when it gets cold.

Looking at Cryosphere Today, are there any measures that track the min-max range for SIA of the crysophere and the individual seas over time (year to year comparisons)?

What I've noticed is this. The min-max range increases for each area as new annual minimums are reached but the rebound during refreeze returns to a historically stable maximum, usually 100% coverage. The CAB, Canadian Archipelage and Laptev Sea are good examples of this. There are others.

At some point, the annual minimums stabilize (approach zero area usually) and as the maximums continue to reach there historical levels the slope of range trend (year to year)flattens.

When maximums begin to fall due to refreeze being impacted, the range now begins to fall. Would such a measure be worth tracking and how might this range metric be interpreted?

I know this is presumptuous but if the metric could reveal something and it does not exist I would like to propose a new cryosphere measure, BICOT.

Biannual Interpretive Cover Oscillation Tilt

or alternatively....

"Baby, It's Cold Out There" (Hopefully this shuts up WUWT.)

This measure would be the range between min-max (biannual)in SIA (cover) as it oscillates. The tilt is to signify the slope of this range measure as we compare yearly trends. When the annual trend "tilt or slope" is increasing this measures the impact of AGW during the melt season. When this slope tilts to a decreasing trend this is measuring the impact of AGW during the freeze. WYDT(What do you think)?

Andy Lee Robinson

Thanks! Scary spirals, and difficult to comprehend that they might be conservative according to new cryosat data. Mind is boggled.

Chris Reynolds

Great News!

Thanks Neven, Dr Zhang deserves some sort of award for his work on PIOMAS, perhaps when the ice finally crashes out...

So PIOMAS is slightly below Cryosat II, but all considered this is a vindication.

Andy Lee Robinson,

Check out this graphic.

That's the volume of sea ice (PIOMAS) contributing to various thickness bands (4 bands, each of successive splits of 1m.

Now imagine what that would look like on that spiral graph.

You'll find all the data you need here:
Which includes 2012's data. It's calculated from PIOMAS gridded data, information on the owning page for that link.

Chris Reynolds


I hate to ask, but I haven't seen a copy of this paper. So before I buy a copy....

You seem to be quoting from it, which makes me think you have access (?). If so: Could you email me a copy? chris886222 at btinternet.com.

And while I'm on the scrounge...

Steve Bloom,

If you read this - you were trying to get hold of a CH4 paper mentioned elsewhere on this blog. If you get a copy could you send me one, email above.

Ac A

OT, but for those still confused about the cap and trade as a useful tool for CO2 mitigation, here is the debunking:




The paper was leaked earlier. Here's a slightly scrambled copy (no figures nor formulars) on GDocs: http://goo.gl/uBk7V allowing comments/discussion.


The leaked version seems to be missing the figures, so I've emailed a copy to Chris. I'll upload it to a server somewhere for wider access when I get a moment.


Djprice57's last comment in this thread, a couple of comments up, was in the spam filter. Not anymore.


The Laxon et al. paper is here - http://www.personal.soton.ac.uk/pgc1g08/grl50193.pdf

@Djprice57 There is a negative feedback following large ice loses in the melt season when the temperature starts to fall. Ice acts as an insulator on the surface of the ocean, so where there is little or none, heat is lost relatively rapidly leading to relatively large increases in ice formation.

As for your new metric, it made me smile, but I'm not sure what extra it could usefully tell us :)

Steve Bloom

Ah, Chris, could you be more specific? As it happens I've engaged in an orgy of paper-requesting in the last week and don't have them organized by subject matter.

Steve Bloom

Oh, and would putting all of these off-topic discussions on the open thread be too much to ask of folks?


Forum will soon be up, Steve. I was waiting for this press release. Besides, as I'm planning to finally build a house this summer, I'm semi-hibernating to do some research on topics such as solar panels and batteries. The amount of info is simply overwhelming. And there I was thinking the Arctic was complicated! ;-)


Actually you can see the ice thickness classes directly from daily JAXA polarized radar (after color renomalization) -- the trick is determining the scale.

The resolution of their key figure is very poor in the journal's advanced pdf version. I put the complicated legend directly on the figures. Hopefully the final html version will show more detail. I can fix the amateurish color palette if the underlying resolution is provided.

 photo cryosat_zpsf2aa8e10.gif


The University of Washington response to this has been reposted on, wait for it, you won't believe it, but... WUWT.


It seems that so many of the faithful called foul on the previous WUWT Sea Ice post that Tony has decided he better post something that even makes any sense.

See comments here...


"February 13, 2013 at 3:04 pm

Folks that are wailing and gnashing teeth here might like this story I just posted: http://wp.me/p7y4l-kHA"

He then, after the UW press release, helpfully provides a link which shows that, at the peak of the melt in 1922, it was considered uncannily weird that a vessel could navigate to 81.29N in ice free waters.

They should have waited until February 2013, with ice-free navigation way North of that...


On a similar note, the ice volume in Jan 2013 appears to be below the minimum volume in September 1979...




ESA has a high resolution version of that figure:



Thanks Nevin....most of my comments might be treated as spam even if this is not my intent.

Dave C

I recently posted a volume chart showing that.

Arctic Sea Ice Volume by PIOMAS


"Arctic sea ice volume has declined by 36 per cent in the autumn and 9 per cent in the winter between 2003 and 2012, a UK-led team of scientists has discovered."

That's a shocking bad hat on that story. Para 1 states a 36%/9% reduction between 2003 and 2012 (10 years). That is so bogus, and completely at odds with the rest of the article. The fact that it comes straight from the NERC makes me facepalm. How many will read the first para only, and miss what follows?

Its a 36% reduction between the 2003-08 average and the 2010-12 average. Since ice volume was declining through 2003-08 and 2010-12, 2003 was surely above the average for the first period while 2012 was probably below the average for the second period. So if you are talking a 10 year decline, it is certainly more than 36% for autumn, and probably more than 9% for winter.

Put another way - inaccurately, but probably closer than para 1 of the press release: If we assume the decline was linear in these two periods (not the same slope on both), average would occur at the midpoints of the two periods: 2005.5 to 2011 - 6.5 years, not the ten years implied. A linear extrapolation to cover the stated 10 year period of 2003 to 2012 would suggest an autumn loss in the range of 50% - 55%.


rant mode off...


Good catch, Frank. :-)


average would occur at the midpoints of the two periods: 2005.5 to 2011 - 6.5 years,

5.5 years?

PIOMAS Oct/Nov average went from 12.65 in 2003 to 6.27 in 2012.
The 50% decline in 9 years seems to be an under-estimate. I get a very unreal feeling about that.


Good spotting, Yuha. That imagery has satisfactory resolution for displaying their grid cells, which are lat/long in standard polar stereographic projection. The latitudinal increment is uniform (meaning area per grid cell is rotationally symmetric but drops precipitously towards the pole) and likely 1/2 a degree (though i estimated 12 steps over 5 degrees around Banks Island).

Centering over the north pole, while understandable, meant that only a quarter of their available pixels were actually utilized by data. A better way to go here might be ice pack centroidal regridding and kmz (google earth file). And of course drop the hoaky black and white nautical perimeter motif.

PNG or Gif (256 indexed colors) is better here rather than jpg format. Jpg makes eye candy while degrading the information content (how many and where are the cells in each thickness class). Thickness binning can only be weakly recovered by posterizing.

Note the thickness scale provided is a continuous gradient -- this makes it a total nuisance to pick out all the ice of a given thickness (eg with GIMP or Photoshop color picker). The white at the very top of the scale is especially inappropriate as it is also used for open ocean.

However there is no real use of the top 1/3 of the scale (4-6 meter thickness) in the CryoSat data and none of it is experimentally validated. These issues are illustrated below Fig 1f. Picking a pure color gives ambiguous thickness.

Look at the Navy sea ice thickness imagery to see how scientific color management (with retention of aesthetics) is done at the higher level.

At some point, we all need to think about really communicating effectively with the outside world. Not just press release staff but also scientists. The death spiral is a fine example: a lot of information accurately and catchingly portrayed.

 photo cryosatHiRes2_zps5effd4ee.gif

Jim Williams

Looking at Andy's Death Spiral, is that June that has fallen from about the same as March to less than January? The fact that any month has shifted that much is interesting, and I'd say that if it is late Spring then this is even more interesting.


Scientific-grade imagery allows such things as quick and quantitative geospatial comparison of Cryosat and Piomas -- without tedious rooting around in raw data files (that you don't have).

Below are a couple of basic arithmetic operations on the high res file. I kept it at native resolution so it is a bit wide, 604 pixels. This type of product became standard (outside of climate science, that is) about 20 years ago.

 photo piomasVScryosat_zps9e342c4f.gif

Chris Reynolds


Thanks, very much appreciated.


No, I can't recall which one. :(
I'll see if I can recall it tomorrow, way too tired now.

Steve Bloom

OK, Chris, clearer head today; must be the scary Russian one. Don't have a copy yet, but will request again (and to a different author if needed) and forward to you when I get it.

Andy Lee Robinson

A friend has thoughtfully just made and uploaded a stunning video compilation on an Arctic theme using a piece of music I wrote a few years ago called "Escape to Osiris".
I'd like to share it with you all because I know you'll enjoy it.



Very nice Andy! Thanks for sharing.


I've been somewhat sceptical of the PIOMAS data in the past, due to the relative lack of verifying data, but the comparison with Cryosat is impressive. I retract all my previous comments relating to the unreliability of the PIOMAS data.

This means the volume declines shown by PIOMAS have to be taken at face value, rather than hedged with doubts about it being modelled. Following PIOMAS we can be confident that there will be a complete melt of the Arctic sea-ice in a melting season well before the end of this decade, and if the right conditions for melt occur it could happen this melt season.

Looking at the wipneus extrapolation graphs, we could have an Arctic free of sea-ice for six months of the year by the end of this decade.

I reckon there's a 1-in-5 chance of the complete melt-out happening this year.

I wonder if they'll ever launch another satellite to look at Arctic sea ice? There might not be any left by the time the next one would be due to go up.

Artful Dodger

Sam Yates wondered | February 13, 2013 at 15:03

"I'm puzzled by the lack of spring and summer data, though; does anyone know the reason for that?"

Hi Sam,

Dr. Seymour Laxon shared this UPDATE to BBC interview with Neven in August 2013 (see point 7):

"CS-2 cannot measure thickness at this time of year with our current processing"

Basically, the way CryoSat-2 measures sea ice volume is by finding the freeboard of sea ice. That is, the height between the top of an ice floe and the liquid ocean surrounding it.

It stands to reason then, using this method, it would be impossible to measure freeboard when sea ice concentration is 100% (no liquid sea water exposed). Converserly, when there is ONLY liquid water, there is no sea ice to measure.

Therefore, this technology works best during the shoulder seasons when sea ice concentration is a middle value.

Again, Dr Laxon wrote to Neven

"the times of year when CryoSat-2's provides data. That is a month during October/November (ON) and February/March (FM)."

Hope this helps.



Despite providing vital information, neither Cryosat or Piomas gives any specific information on ice pack dynamics, that branch of classical mechanics addressing forces and torques and their effect on motion.

Given the lower moment of inertia, these forces now may result in more melt ponds in partly refrozen fractures, ice moved into warmer or stormier Beaufort of Laptev water or exported out of the system altogether, it will cause ice volume prognostications to overshoot on the 'conservative' side.

Arctic Ocean ice is a curious substance, with significant geospatial variance in thickness, internal temperature profile, state of brine exclusion, and previous fracture, melt, and refreeze history. The older thicker ice is quite brittle and not so subject to plastic deformation (ie, forget about Young's modulus and bring on the Cauchy stress tensor).

This winter, we've been seeing three failure modes of older ice under extensional forces: arch fractures in line with applied normal stress, streamline fractures responding to tangential velocity differential shear, and more recently ice fabric ripping following oblique shearing forces.

The two-frame animation below (951 pixels wide at native NOAA-19 avhrr resolution) is marked up for a remarkable event, a progressive sequence of arch fractures now overprinting on a double oblique shear. If this keeps up, all the older ice implicated in arch fracturing will be rounding the spit there at Nordøstrundingen, the geometical feature defining the point of no return for ice export down the Greenland coast.

 photo EllesmereMaster2_zpsb237ce49.gif



What amazes me is that fracture occured in a 4-8 hour period across hundreds of miles.

I posted the frames on this webpage to illustrae the process:


As I asked in a previous post, I wonder if anyone has studied the potential links between small intense Arctic SLP's and fracturing - since one passed over the pole around the time of this event,


I have updated the METOP 2 IASI CH4 imagery through February 12, 2013 pm.

Methane hit 2239 PPBv at 742 mb at some locations in Russia or Sea of Okhotsk during that period.



Wipneus - I take the years to be inclusive, so 2010 - 2012 is three autumns (not two). Hence my 6.5 rather than 5.5 as a straight subtraction would give. But either way, its a lot more than suggested at the head of the article.

Anyway, my ranting aside, its good to see another source validating the quality of PSCs model. Many here have invested a lot of energy in interpretation and visualisations of that output (with excellent results). Boosting confidence in the fundamental quality of the reference data in always nice.



The date you mention is spooky in so many ways.


Chris Reynolds


Yes 'the scary Russian one' there can't be too many of them and the abstract did read scary.


A4R writes, 'What amazes me is that fracture occurred in a 4-8 hour period across hundreds of miles. potential links between small intense Arctic SLP's and fracturing? one over pole time of event.'

Right, this was a colossal, abrupt release of energy in the pitch dark; no one witnessed it except for a handful of satellites.

The propagation speed? Fast, like a breaking plate glass window. But no faster than the speed of sound (respectively shear waves) in ice, affected by bubbles, layering, salt, temperature profile,and fracture/refreeze history. The two free full texts below measured it under lab conditions and with seismic waves in Greenland. Let's just say 3.85 km/s for sound and 1.90 km/s for shear velocity.

The major shear zone pencils out to ~850 km which would require 447 seconds or 7.5 minutes. The ~45 km wide fracture zone also happened rapidly, and the minor lower shear zone occurred concurrently. So 528 miles in 7.5 minutes.

Hmmm, I am trying to picture a 28 mile wide crack system in the freeway from Tucson to Los Angeles opening up in 7-8 minutes.

It seems possible that such an event registered with seismometers, perturbed the earth's rotation, or wobbled the pole. These are measured continuously with exquisite sensitivity -- though I have no idea where that data is stored and have not checked.

H. Kohnen, 'The temperature dependence of seismic waves in ice' J.Glaciol.13, 144–147 1974

Christian Vogt, 'Speed of sound in bubble-free ice' J. Acoust. Soc. Am. 124 6 1986


Lodger: That did occur to me as a possibility, but if that was so, wouldn't the data be limited to spring and mid to late summer, with empty patches during the minimum and maximum? Instead, we only get data during the refreeze, with none during the melt, when I'd think...


Hm. Not sure if this is correct, but it occurs to me that the problem might be melt pools on the surface of the ice. After the minimum and on up to the maximum, the pole is shrouded in darkness, and there shouldn't be any melt pools on the surface of the ice--so if the satellite detects open water, it's definitely a crack in the ice itself, and not water pooling on the surface. During the melt season, though, you would get multiple pools forming, which would (depending on the ice thickness and its surface geometry) give multiple different values for the level of the water, thus preventing an accurate calculation of the ice freeboard. I suppose one might get around that by devising an algorithm that only looked at fissure-shaped patches of water, although I don't know enough about how the ice behaves to know if that would really work.

Chris Reynolds

Lodger, Sam,

It's because of melt ponding. The algorithm used relies on the scattering from snow/ice versus direct reflection from leads. During the melt season direct reflection from melt ponds would screw up the retrieval.

Aaron Lewis

I have been warning you that the ice was fragile and would break up rapidly. You though I was just an alarmist and forgot about what I said. Well, here it is.

This has some little interest because it changes ice surface area and total melt rates.

It was a release of stress, with much of the energy going into breaking ice bonds. Films of melt water formed in the fractures. Much of this melt water remained in the ice, and will facilitate additional fracturing and melt inside the ice. Now, sun light can melt the fractured ice from the inside out. The conversion of ice to water absorbed much of the energy that in rock would generate seismic waves. In most geologic events we have displacements of material of very different specific gravities. For example, rock displaces water or rock displaces air, and the change in mass distribution is significant. Here ice displaces water, and the total change in mass distribution is small.

Net, net, the effect is the event left energy in the very core of the ice so that the energy required to melt the apparent volume of ice is less than the nominal heat of fusion. And, those films of water in the ice change its transmissivity.

dominik lenné

This Cryosat data release story is absolutely sensational, a true scoop!


Indeed, as A4R and Aaron remark, how did the ice pack stress arise in the first place, where all did the potential energy go when it ruptured, do the sequelae have any significance for Piomass? There had to have been very substantial recoil on the southern part of the ice sheet pressed against Ellesmere.

Are oblique shear events enabled by current ice conditiosn or have they always been a steady feature? Let's just say it is vastly more difficult to shear thicker colder ice, whereas rotten wet ice isn't brittle to begin with.

I'm hoping that A4R can capture the sea level pressure event preceding the rupture with a graphic series. How long it takes to get reanalysis and accurate surface wind directionss, I couldn't say. NSIDC writes for January 2013:

"The dominant feature of the Arctic sea level pressure field was unusually high pressure over the central Arctic Ocean, consistent with a predominantly negative phase of the Arctic Oscillation ... Air temperatures at the 925 hPa level were 2 to 5 degrees Celsius (4 to 9 degrees Fahrenheit) higher than average across much of the Arctic Ocean."

Ice pack stress arises from differential motion (or attempted motion), with attribution (wind or current) changing with the season and geospatial location. It is feasible to capture ice pack motion directly from radar imagery, the issue being temporal resolution afforded by once-a-day composites. However I have a new scheme for high precision velocity field extraction, stay tuned.

For now, canned animation products like Navy thickness and speed-and-drift provide this. It appears shear lines more or less correspond to ice thickness lines, the boundary between green and blue in the animation. This would make some sense because mechanical properties of ice would track with their age/thickness/history. The overlay below is imperfect but that may arise from (undisclosed) map projection differences or satellite image rectification.

 photo febMoves4_zps14115a29.gif


We're headed offline to the Sea of Cortez for the week so please not too many blog comments or I will never get caught up.

Here is something to ponder: does either Cryosat or Piomas fully capture the structure of the ice out there? Jaxa polarized radar thinks not. I enhanced the 14 Feb image below to bring out features in the ice pack present in the original imagery but not apparent to our eyes. While there are infinitely many ways of tweaking images, these features are quite robust to manipulation, both on this date and indeed the last 30 (ie, are deep structural properties).

It's fair to say that multi-year ice jumps out (red arrow) and largely corresponds to its Cryosat/Piomas/Navy depiction. However the substructure is far more nuanced. It is said that modelers, given a contradiction between observation and model, go with the model. Radar may not be immediately interpretable but it doesn't lie.

The yellow arrow pinpoints the 'pinwheel'. This is older ice that broke off in late summer. Because the two arms make it easily recognizable, it serves as long -term tracking buoy for both displacements and rotations.

The blue arrow highlights the issues this year from the Bering Straits along to Barrow, seen to a slightly lesser degree in the whole Chukchi and Laptev seas.

The purple arrow shows the boundary of the flimsy new ice at its confluence with the Fram Strait exit.

The teardrop at the North Pole is an artifact of satellite non-coverage.

 photo jaxaICeStructure_zps21ab0427.jpg

Aaron Lewis

In the old days the ice was colder, stronger. Much of the stress was less than the amount required for fracture. The ice was able to relive stress by cold flow and deformation rather than by fracture. Where fractures did occur they were smaller and films of water in the fractures refroze quickly because the surrounding ice was cold enough to absorb the heat without approaching its melt point.

Now the is weak and warm. It breaks rather than flowing.

Artful Dodger

Hola, A-Team! Trabajo o placer?

Yes, the SIRAL instrument aboard Cryosat-2 captures the 3-D structure of sea ice, with about 250 M resolution (it sends a radar pulse every 50 ms while orbiting at about 7 km/sec, so it moves forward about 250 m between each pulse).


BTW, the sea ice keel is either flat or evolving to flatness, due to the temperature stratification in the water. If it sticks down too far it'll melt, or soften and slide up since ice floats. Conversely, thin spots thicken more rapidly than thick ice due to poorer insulating properties.



Ola, Sr Lodger: vamanos a Puerto Penasco por kayak de mar, flor desierto temporada pico y jarras de margaritas.

To echo what Aaron has been saying about the remarkable consequences of hydrogen bonds of ice, water and vapor, these emanate from its electric dipole, pKa for dissociation, 2p4-driven dihedral geometry, low molecular weight and crystallographic space group P63/mmc (as worked out in 1935 by Linus Pauling).

What it boils down to is the oxygen-oxygen bond angle in the ice Ih lattice is tetrahedral (109.5), about matching water's dihedral angle (105) -- a lot of anomalous properties of ice (and water) follow from this meeting of R3 packing symmetry options with quantum mechanical bond angle forcing. So despite the graphite-like planes, ice is very resistant to shearing. (Note: real ice is vastly more complicated than a lab crystal.)

Recalling how James Hansen got his start -- on the atmosphere of Venus, 90 atmospheres of carbon dioxide, sulfuric acid clouds, run-away greenhouse raising the temperature an extra 400ºC -- we might consider a new thread on properties of alternative oceans such glycerol, ammonia, or acetic acid (never mind the molten sulfur of Io or liquid hydrogen on Jupiter), the idea being to sort out contributions from hydrogen bonding, mass, solvent polarity, freezing, vaporization, sublimation and so forth.

These fast gigantic fractures of the Arctic ice pack must release a lot of energy as sound. The recent sonic boom of the big meteor over Siberia was easily detected in Alaska as low frequency sound waves -- by the array in Alaska that normally listens for nuclear bomb testing. This has got me wondering if the 11 Feb shear event showed up too.

In the best case scenario, ice fractures would have a distinct frequency signature. We could not only time onset and duration precisely but by going through the last decade of archives, test Aaron's proposition that events are much more frequent in today's ice.


Outstandingly clear conditions over the pole today. Incredible third crack system overlay beginning. Full image is 1247 pixels wide, suitable for desktop wallpaper.

 photo ellesmereWallpaper_zps42c1f19a.jpg

Chris Reynolds

A Team,

These fast gigantic fractures of the Arctic ice pack must release a lot of energy as sound. The recent sonic boom of the big meteor over Siberia was easily detected in Alaska as low frequency sound waves -- by the array in Alaska that normally listens for nuclear bomb testing. This has got me wondering if the 11 Feb shear event showed up too.

Someone could contact CTBTO,
The site is at Fairbanks Ak, so may be part of the university there. As for whether it would release enough infrasound. I doubt it. I suspect it'll be a rapid succession of higher frequency releases as the lead unzips.

Pedant Time...

Definition of a Sonic Boom from Wikipedia "A sonic boom is the sound associated with the shock waves created by an object traveling through the air faster than the speed of sound."

The explosion over Chelyabinsk was not a sonic boom.

The impactor was travelling at around 18km/second, weighed ~7000tons, and exploded 12 to 15 miles up. Now assessed as having a yield of the order of 300kton or more. The flash shows that the primary cause of the shockwave was not sonic boom but an explosion.

Sonic Booms don't make flashes.

I only say because there are a lot of confused but assertively incorrect people over on Youtube. If people could just call it what it was - an explosion.

Kevin O'Neill

The use of seismology in monitoring arctic sea has already begun: Quantifying the influence of sea ice on ocean microseism using observations from the Bering Sea, Alaska

A journalist's description of the research can be found here: Arctic Ice's Hardiness Measured with Earthquake Monitors

Kevin O'Neill

Non-paywalled copy can be found here: Quantifying the influence of sea ice on ocean microseism using observations from the Bering Sea, Alaska


Chris Reynolds, exploding is laymans terms for what happens when a hypersonic object is slowed down by atmosphere with larger forces then its structural integrity can handle and the spontanous disassembly increases the breaking force and aerodynamic heating by increasing the objects area. Enough compression heating of atmosphere and friction heating and matter glows bright.

Thousands of tons moving at several km/s do of course make a massive sonic boom, even if the mass breaks apart. Then every piece made its own shockwave that merged to a rumble so loud that my meager understanding of english fails me.

We were lucky that the angle of entry were shallow and that he object broke apart and deposited most of its energy high in the atmosphere.

Sadly I am a simple layperson, you can find much better descriptions then mine.


What did i get thousands from? *sigh*


The long fracture line in A-Team's image above developed right after a storm moved over the pole.

The series is available on this webpage - see the left column:


Chris Reynolds


Then what is the technical term? Surely the flash, bright enough to dwarf sunlight was enough to show the shockwave wasn't due to sonic boom. Add to that the pressure up there (50 to 30mb) against the pressure at the surface (~1000mb) and it's clear that most of the shockwave dissipated to space. What hit the ground was a small part of the causative energy release.

Peter Ellis

the shockwave wasn't due to sonic boom

This is meaningless. A sonic boom is a shockwave, and vice versa. It simply means that something is travelling faster than the speed of sound, and so the compression waves all stack up on top of each other.

In the case of an explosion, the thing travelling faster than sound is the expanding hot gases from the explosive reaction. In the case of an aircraft's sonic boom, it's the bow waves from the aircraft's movement. In the case of the meteor, the movement is sufficiently fast to heat the gas surrounding the bolide, so you get both processes going on.

Chris Reynolds

Peter Ellis,

It's not meaningless, many meteors hit the atmosphere at high speed but don't shatter windows on the ground. You do get both processes going on but it was the release of energy from the fragmentation of the meteor and the resultant release of energy that hit Chelyabinsk.

Where are all the shattered windows under the track of the meteor prior to its detonation upon fragmentation? There aren't any.

More info here:
NASA now say the explosion was 500ktons. That much energy was not from a sonic boom.

A 500kt sonic boom - with the energy release betrayed by a flash that was brighter than the sun being merely incidental...

Sir, you stretch my credulity.

Peter Ellis

I think we're at major league cross purposes here. I'm not denying that the object fragmented explosively, causing a shockwave. The point is that this is still simply a conversion of the kinetic energy of a moving object into sound/pressure waves, i.e. the same process involved in generating a "normal" sonic boom.

There was no extra input of energy (e.g. chemical or nuclear energy in a bomb, electrical energy in a thunderclap), just the kinetic energy of the incoming rock.

Peter Ellis

Putting it another way, "sonic booms" are (the sound caused by) a particular subset of "shockwaves". Your definition restricts it simply to being the bow waves from objects moving faster than sound. I'm using it to mean any shockwaves caused by objects moving faster than sound, including those caused by frictional/compressive heating of the atmosphere.

Wikipedia doesn't help: either of those definitions is technically valid. Either way, it's a bit of a sterile debate. Changing the words doesn't alter the physics, which we all agree on anyway!

Peter Ellis

Final pedant point: there is no "release of energy from the fragmentation of the meteor". Fragmenting a rock takes energy, as you'll appreciate if you've ever hit one with a hammer.

The energy source is the stored kinetic energy of the rock, which gets dumped into the upper atmosphere as heat energy and compression.


We have strayed far from the Arctic ice. But I think there are interesting comparisons.

It is all too easy to fall into the either A or B trap, with reality being much messier and more interesting.

As a meteor enters the atmosphere, it starts at high mach number and low resistance. As it plunges deeper the atmosphere around it thickens and resistance rises rapidly. A bow shock forms early on. Across the bow wave pressure and temperature change dramatically.

The bolide is heated by friction and radiation. Depending on its composition, the surface may heat far more than the interior with a delay for conduction. Stresses build quickly as the hotter outer surface tries to expand and the colder interior resists.

If the structure is heterogeneous, these stresses can rapidly shatter the bolide and generate explosive forces tearing the meteor apart and rapidly increasing its effective cross section subject to heating.

If the meteor contains volatiles but is structurally strong, it can become a high pressure container that will ultimately fail releasing the stored thermal and pressure energy resulting in disassembly of the body. As before, the debris created rapidly expands increasing the area and the rate of thermal heating.

In effect each of these acts like a bomb going off. The kinetic and stored energies are released rapidly in a growing cloud.

So, back to the ice. The failing ice also stores energy structurally. This too can be released suddenly, albeit at much lower energy densities.

If the ice has bubbles trapped in rapidly formed ice, it can and does structurally weaken it, allowing fracture ruptures to occur far faster than lab experiments might suggest.

As the ice thins, the conditions change. Breaking a cube is far more difficult than flexing and breaking a sheet.


Looks like Greenland's ice melt is getting off to a bad start (more melt than we would like to see). The SST anomaly's map doesn't look particularly good, with very warm anomaly's off of the southeast and northeast coast of Greenland, a warm anomaly in the Arctic. If Greenland is getting off to a bad start, that doesn't bode well for the Arctic either.


Even from a "non-scientist" (but a trained observer)....this spring is NOT setting up well for either the Arctic OR Greenland. It is looking more and more like another heavy melt year for both.


What do people think the volcanic activity in Siberia will do to this years melt?

Just Testing

FYI: if that huge fracture occurred at night with a clear sky it should have been picked up by optical satellites. Thing to look up: Fractoluminescence. You can try it with a hammer and a sugar cube or ice cube in the dark.

Chris Reynolds

It's puzzle time!

Seriously I think it could be useful if as many commenters give their opinion on that little puzzle. As I know the answer I can't judge.

Which of the images in that blog post are from 2013?


Oops, I may have inadvertently ruined the puzzle with earlier post that subsumed your out-of-focus Morris Jesup DMI image within a broader synoptic-scale streamline crack.

Quite a bit of new, fast and ongoing major cracking today in the Beaufort Sea and also around the pole (as captured on A4R's site). The animation below covers 18-22 Feb 2013. Barrow is the small finger of land left of center top; the north pole lies below the bottom right corner.

John C and Chris are asking how this affects Piomass/Cryosat predictions for the summer of 2013 minimum. The short answer is adversely.

Cracks in first and second year ice are hardly a new phenomenon -- they've been studied for thirty years, as have cracked thick ice (floes) going into the Fram.

It's all about today's core multi-year ice which is thinner and more susceptible to brittle fracture than ever before.

The cross-fracturing we're seeing on 1000 km scales potentially exposes multi-year ice to unprecedented export out the Fram and Bering straits as well as much more rapid melting in situ (because of more melt ponds, more melt perimeter, more salinity, more susceptibility to waves, loss of pack contiguity, and relocation to warmer waters).

In winter, only the NOAA-16 infrared satellite provides sufficient resolution to map Arctic ice pack cracks. Our Canadian image source only provides a rolling 3-day web archive -- we have no coverage for past winters unless someone here snagged it. Even if we could locate a friendly long-term archive, it is not so easy to quantitate and compare total crack length and width for different years because cracks freeze over, re-crack, lie under snow, and cloud over.

For the early literature, I recommend 'Brittle failure of ice', a 48-page 2001 paper by EM Schulson. It has been cited by 107 subsequent papers. It reviews Arctic sea ice leads in terms of the brittle failure of polycrystalline ice Ih, columnar-grained S2 first year ice, tensile behavior (nucleation and propagation of cracks), compressive failure (frictional crack sliding, wing cracking, comb cracking), the ductile-to-brittle transition under compression (competition between crack-tip creep and crack propagation).

'Characteristics of pack ice stress in the Alaskan Beaufort Sea' J.A Richter-Menge JGR Dec 2012

'Spatial and temporal characterization of sea-ice deformation' JK Hutchings, Annals of Glaciology 2011

'Low-frequency bursts of horizontally polarized waves in the Arctic sea-ice cover' D Marsan Journal of Glaciology 2011

'Arctic sea ice velocity field: General circulation and turbulent-like fluctuations' P Rampal JGR Oct 2009

'Spatial scaling of Arctic sea ice deformation' HL Stern JGR Oct 2009

 photo beaufortLateFeb5_zpse552f61e.gif

Artful Dodger

Thanks, A-Team. The animation above shows clearly why there is no mass balance site at Barrow, AK this year: there's no sea ice.

Unfortunately, the Barrow sea ice webcam is still down as well:


Chris Reynolds

Puzzle answers and an explanation of what I'm thinking are here.

Thanks to those who responded.


Like Artful Dodger, I'm also concerned about persistent mid-winter open water off Barrow, Alaska. This new crack system working its way down from Barrow to Banks Island may be the harbinger of early ice melt and export in this region.

The image below (648 pixel width, native resolution) was enhanced to draw out the next big crack that may take shape over the next few days.

Note the channel 4 AVHRR infrared imagery can do a really good job on ice thickness too (darker ice corresponds to polarized radar and Piomas/CryoSat thickness depictions).

I wonder if this event is associated with record northwards import of 'warm' water in 2012 through the Bering Straits -- indeed, if that has continued this winter under the ice. Here we might be paying better attention to the latest papers of Rebecca Woodgate, the physical oceanographer monitoring the fixed current/temperature/salinity buoys north of the Straits.

 photo NextCrack_zps2c24dfd2.gif



Thanks for this, I have saved about every Beaufort AVHRR image that was readable or clear since Feb 18. Once you run through them in play mode, it is amazing how quickly this is breaking up, and the ice is moving toward the Bering Strait.

In my opinion, without checking HYCOM/CICE, I think the main source of break is stress from potential warmer water under the ice with currents shifting it.

Your arrow above will likely be another break in the next 3-4 days, given what I have seen in the last 5 days of activity.

If warmer water and currents are working in interaction, while some of this may refreeze, the motion may slow or in some cases, prevent that process.


Hard to improve on Chris' description of older animated QuikSat radar: "the hypnotically beautiful pulsing and moving of the ice cap, like a living organism, as the Arctic Oscillation shifts from positive to negative index." That satellite did not have sufficient resolution however to display the crack situation.

It's fascinating to watch 'inexplicable' ice pack motion in Jaxa-IJIS daily imagery from the 2012 mid-Sept minimum to late February 2013, though it too only captures a fraction of the cracks that are really out there according to the 10.8µ infrared. Jaxa is radar at two frequencies and two polarizations 36 Ghz v 36 Ghz h 18 Ghz v.

Animation is easily done by downloading their monthly archives and, for Mac users, setting Preview preferences to "open groups of files in the same window". Just drag all 150 images over to the Preview icon in the dock. Using up and down arrows then makes a very fast faux-animation that you can adjust, pause and reverse at will, deleting extraneous frames. Then 'open as layers' in Gimp, crop to the Arctic Ocean, adjust contrast etc, and save as gif animation at desired frame speed.

I did that below with 'scatterometer' ASCAT imagery from 01 Dec 12 to 22 Feb 13. This is just single channel radar at 5 Ghz, so grayscale. It could be mixed as an additional channel with Jaxa to false-colorize it more informatively.

It shows a block of newish ice (initial frame, yellow outline) pushing down on the multi-year ice and squeezing a good part of it out the Fram (final frame, purple outline).

There seems to be good export action out the Bering Strait as A4R observed.

Jim Hunt


Thanks for those tips. If you check out this conversation we're having over on Chris's blog, you'll note I've been trying to produce a similar video, but zoomed in on the Cape Morris Jesup to Fram Strait area. I'm having trouble seeing the cracks, coz clouds keep getting in the way (on the DMI images at least). Can you suggest a better place to look for suitable images, preferably with archives available for at least a couple of years?

By way of experiment on my part, here's how the cracks over in the Barrow direction are progressing:

P.S. Having just checked my links, I see Chris has a new "Beaufort Lead" post too.

Chris Reynolds

A Team,

Thanks for the graphic, it perfectly shows something Neven was asking about - the flattening against the CAA and spread into Beaufort of the multi-year ice.


Jim, nice photo above, every day brings a new twist. It's from 24 Feb 2013 at 19:41 in a time zone the archive-keepers never specifiy -- maybe Greenwich or maybe the Resolute, Canada receiving station (or maybe campus time for the principal investigator).

I am not keen on people calling these features 'leads'. Sea ice has a controlled vocabulary under the World Meteorological Organization. Leads are openings in the ice that are *passable by a surface ship*. So we're going down the rabbit hole again in the Beaufort, meeting the Red Queen half way.

The big opening has very unusual and rapidly properties, it shows up pink on JAXA-IJIS. What does that mean? Well, it probably means the same as the other pink sites on the same image. Whatever those mean: coastal, the least solid of ice classes. Looking at the individual RGB color channels, the 36 Ghz vertical and horizontal channels (red, green respectively) already furnish the pink, never mind the 18 Ghz V (blue).

 photo pinkBeau_zps5da3a949.jpg

Chris, thanks for fantastic work tracking down all that archival material. After many billions spent on the satellites themselves, it is so odd to see follow-up consisting of disappearing data, crummy front ends, no one home @ admin, no legend explanation, no FAQs, no literature citations -- all this cuts into utilization.


However your longwinded search (ditto my end) raises the questions, who besides us ever looks at this stuff, do they throw away imagery from past years, store it offline, or dumb down the resolution -- when memory cost a dollar for 5 years of images? Why am I having to stretch HSV contrasts, cut Arctic Ocean masks, filter wavelets on thousands of images before I can sit down to work? That was their job, from day one.


A-Team, Chris, thanks again for the imagery. I have been saving it but no time to post. I am in the process of updating the CH4 imagery from METOP 2/IASI.

The CH4 I have added is through the 17th, but one observation is that where these fractures and thinning areas are in the Okhotsk and Bering, there is high levels of methane overhead at many of them. Some levels are over 1950 as high as 2200 PBBv. There are similar releases in inner Mongolia, which may be permafrost related.


I'll add more images after I get through a major work project.


The chances for the North Pole to be wide open have greatly increased given the migration of first year ice over it. As with March maxima of 2012 the blue print for this years melt is about to be set,
so I give a 60% chance for a wide open North Pole . This will be the highlight of 2013 if it happens.

Kevin O'Neill

A-Team, as I think you know, the data from these satellites is not in image format. The processing of the satellite data to turn it into images is science. A slightly different processing algorithm will yield different images. So, it is only important to save the original data. Any scientist working in this area would be processing the original data himself/herself.

Jim Hunt

A-Team - Thanks for your kind words. Not bad for a first attempt? Any thoughts about how best to see the cracks through the clouds above Nord, in order to display them in a video?

By way of illustrating Kevin's point here's how to access CryoSat data, as opposed to images.


As further illustration of the methane release in the Pacific and Atlantic Arctic regions, the methane release imagery is updated through Feb 19 2013 am.

There was wide spread release or concentration in the Atlantic, Russia, China and Norwegian, Barents and Kara Seas.

See: https://sites.google.com/site/a4r2013metop2iasich4co2/home/2011-airs-ch4-359-hpa-vs-iasi-ch4-970-600-mb


The mid-February breakup we're observing in the Bering and Beaufort appears to be very unusual, possibly unprecedented in recent millenia, for this time of year. In the spring of 2012, something rather similar happened but in April, as noted by BftVoid in a recent forum post.

Below, I made an animation covering 12 March to 17 June 2012 using Terra satellite visible imagery at 4 km resolution pixels. After beginning above the Bering Straits, it really takes off on day 82 (March 22) and by day 100 (April 9) begins to strongly resemble mid-Feb 2013. On day 108 (April 17) it has reached its geographic terminus, Banks Island.

If taken as a simplistic predictor of the 2013 melt season, we are 51 days ahead of last season.


That's a lovely little animation!

Kevin writes, "the data from these satellites is not in image format. The processing of the satellite data to turn it into images is science. A slightly different processing algorithm will yield different images. So, it is only important to save the original data. Any scientist working in this area would be processing the original data himself/herself."

That sounds quite reasonable but actually isn't the case -- nobody can beat the principle investigator's team (designer of the imaging instrument) at their own game. Level 1 and level 2 processing are provided for most satellites. That takes it well out of raw signal territory.

The vast majority of scientists using this data are higher in the food chain (like me) and have very different uses in mind than the PI did. We aren't going to see a forum started on radar sigma0 or 3µ vs 10µ avhrr temperature scales. It's enough to know that dielectric constant and surface roughness determine radar return and that clouds mess up infrared returns but it's the best mid-winter imagery around.

My beef is really with the lack of central repository, lack of ftp access at many archives, lack of documentation, lack of file retention, lack of response to inquiries, lack of routine secondary products and so forth.

For example, it is very tedious to do year-to-year comparisons yet that is a no-brainer to pre-provide. In a nutshell, it is very inefficient for 5,000 people to repeat the same multi-hour procedure that 1 specialist can do better with a couple clicks of the mouse.

Kevin McKinney

Thinking about the conversation above with Kevin & A-Team, and combining that with these 'lovely'--to use Neven's entirely appropriate word--animations, it looks to me as if an entire user community is coalescing. Maybe it's time for the process to become more intentional, somehow?

Don't know how to do that, myself, but... if PIs know that there is the interest, and if there's some forum for conversations about optimizing data usefulness, then maybe a whole bunch of mouse clicks can indeed be made redundant? After all, an involved user community also means political support for funding--something we've already seen to be threatened by tight budgets and denialist politicians.


I often thought about creating some central depository of all the stuff I put on the Arctic Sea Ice Graphs page (and there's much more out there) that would make it real easy to compare to previous years. For instance, the guy who helped me set up the forum, also has a script that saves all DMI SLP and SAT maps on his server for me, because DMI doesn't have them on hand and saving the images myself (which I did for quite a while) is very tedious.

But with no programming skills, I wouldn't where to start. And in the end I think only a small amount of people would be really interested. And the ice might be gone by the time an interactive archive is there.

So yeah...


Jim, that is a good idea to be monitoring the Fram from Nord vantage point.

One method for digitally stripping off the clouds involves selecting them by temperature and locally adjusting the grayscale histogram to blow up cracks in the floes. But at the end of the day, there just wasn't a whole lot underneath the clouds that got up to the satellite.

Alternatively, you could mask off the clouded regions and easily enough stub in cloud-penetrating radar rescaled to the projections. But the radar imagery archive we have access to doesn't provide sufficient resolution.

Visible imagery is coming on this month and while it has even less cloud-penetrating capability than infrared, you might get a break on timing of passage overhead.

DMI has quite a nice interface. The best bet is to quickly scan the thumbnails and pick the time when Nord is mostly cloud-free. Or as the clouds move on, merge the good parts of two images taken very close in time. Here you can take many hundreds of consecutive images, open-as-layers in the freeware GIMP, and merge down after setting relative opacities.

Even with all this, your final animation will be a little jumpy as a time series. That's ok! You'll discover a lot of cool and unexpecting things just from immersing yourself directly in data.


Great comments there by Kevin and Neven. I find that somebody on this blog almost always knows where the goodies are stashed, very helpful. Less ambitiously than providing a total clearing house, we could put together something like an annotated 'best links' tab (jump station).

Working together like this has already created an extraordinary synergistic community. The straight scientific world is structured more on competitive lines -- get the next paper out, get the grant renewed, survive another year -- so cooperation is held to a bare minimum.

We can do better than this -- there is a reason for more ant biomass on this planet than wolf. In fact, we're doing better already cooperating -- how many 2012 journal articles were still yakking about summer sea ice lasting til 2040/2080/2100?

While cooperation makes it easier and faster to follow unfolding events, communicate them to people with varying kinds of background and expedites our own research directions, as Neven notes, this is not going to have the slightest effect on how events unfold in the Arctic. I wouldn't recommend sea ice to a young person as a career direction.

Jim Hunt

Kevin - "If there's some forum for conversations about optimizing data usefulness"

How about the shiny new Arctic Sea Ice Forum? By way of example:


A-Team - Thanks for those additional tips! I'll experiment further as soon as I have a spare moment or two.

Kevin O'Neill

For those who haven't yet discovered it, the main archive for NASA ocean & climate data is the Physical Oceanography Distributed Active Archive Center or PO.DAAC

From the PO.DAAC 'Help' page:

The Physical Oceanography Distributed Active Archive Center (PO.DAAC) is an element of the Earth Observing System Data and Information System (EOSDIS). The EOSDIS provides science data to a wide community of users for NASA's Science Mission Directorate.

The mission of the PO.DAAC is to preserve NASA’s ocean and climate data and make these universally accessible and meaningful.

Since the launch of NASA's first ocean-observing satellite, Seasat, in 1978, PO.DAAC has become the premier data center for measurements focused on ocean surface topography (OST), sea surface temperature (SST), ocean winds, sea surface salinity (SSS), gravity, ocean circulation and sea ice.

In addition to providing access to its data holdings, PO.DAAC acts as a gateway to data stored at other ocean and climate archives. This and other tools and services enable PO.DAAC to support a wide user community working in areas such as ocean and climate research, applied science and industry, natural resource management, policy making, and general public consumption.

Thanks to NASA's open and free data policy, we are able to serve users both in the United States and worldwide.

The PO.DAAC facility is managed and located at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.


Most of the Beaufort Sea ice shredded between 26 February 1903 pm and 27 February 0326 am. It is a series of cracks that are widening that extend almost all the way to Banks Is.

A-team, it seems we have a much earlier repeat of last year.

I suggest we have three results from this process:

1) More ice flowing from the Beaufort into the Bering,
2) The multi-year sea ice being pushed away from the NP will move south into the Beaufort Sea and melt during this summer.
3) A third impact is elevated methane readings at Barrow. They are already occuring in February.

I have posted the two AVHRR images for comparison at:


Jim Hunt

Morning A4R.

I already noticed, and I'm currently debating the issue with 1,738 sceptics:


I hope that's OK, particularly with A-Team and Neven. Please advise ASAP if not, or if you'd like more/different links.

Mike Constable

I had suggested (in previous years) that the increase in sea-ice in the Bering might be due to cold surface water flowing from the Beaufort.
The flow would also leave space for more warmer water to enter the Arctic from the Atlantic side, which would help explain the low ice on that side?


Not sure if it is worth posting

There are no dates on the video. If you compare to




pointing out that these pictures are 30 and 40 days later during 2012.

51 days seems a little over the top to me. Perhaps 40 days?


As A4R observed, the Beaufort crack system has gone absolutely haywire in the last day. It has reached the limits of Banks Island and is now showing signs of continuing poleward (rather than going past Banks into the residual thickest ice).

I colored in a perimeter of one of the floes -- it vaguely resembles a human face and neck in profile. Watching it, after getting past the jitter intrinsic to variable satellite angle, it shows unmistakable clockwise rotation. So something is torquing the ice. Note too that the crack pattern shifts dramatically from jagged floe to brittle fracture (chonchoid) as the ice starts circling.

The scale is 43 pixels per 100 km. The crack system extended 556 km from Feb 21-27 in normal (perpendicular) direction, at just over path walking speed (2 miles per hour). At the widest spot, it was 19 km wide.

I'm still thinking about what -- if anything -- this striking event portends for the summer melt season. If the end-game has shifted to winter, the melt season may now be a bit anti-climatic (foreseeable outcome).

Watch this space ... Every few hours brings more astonishing frames to add (not so trivial). I will continue with embedded explanatory annotations to make it more transportable and accessible to non-specialists. The link will be stable, I will just overwrite the file name.

Jim Hunt, thanks for providing taking time to furnish information to the sceptic community. I am not 'attached' to anything I post, it's all open source, it's all in the public domain, credit the satellite if anything.

 photo beaufortIcyBlueMiniYellowText3_zps44a47395.gif

Espen Olsen


FYI:The cracks now reached Banks Island and are now entering the straits north and south of the island.


Thanks for the tip, Espen. An additional 8 images have come in since I made the animation this morning (grrr) and more are due overnight.

The crack system has not only reached the shores of Banks Island but has widened considerably. The three cracks interior to Banks have been there unchanged for a couple weeks.

The poleward extensions have reached 85º N, way off the boundaries of my 420 pixel wide typepad animation (more grrr). Clouds, large patches of artifactual contrast, and off-nadir blur make these newer images problematic to assimilate.

To follow the excitement yourself, the best Beaufort photos are at the link below. I see now that the Resolve, CA receiving station is taking data from 3 separate satellites, NOAA-15,-16 and -19. These are polar orbits but with differences. The photos have the same nominal nadir but have otherwise not been uniformly rectified. This accounts for the jitter with respect to white land outline and lat/long.


It is easy enough to rectify the ground imagery (at least locally) but then the white overlay takes on the jitter. This is a common mistake I see all over the place, though not however at Jaxa or Modis. It is better to provide a pure image and the overlay as a separate file (which users then float in the mask stack and perhaps eventually merge in themselves). Or the north pole can be marked and the off-image perimeter for lat/long. Or little white crosses at lat/long intersections. Or nothing - most of us know where the CAA and Greenland are already.

Lots of Arctic sunlight now -- enough for Terra to take in the Beaufort crack system in both RGB and the 367 channels false color (see link below for wavelengths). These have phenomenal ground resolution (though going from 4 km to 1 km gives 16x the file size). I've attach a recent 367 image of the crack system just to get people jazzed about using this for ice/slush/crack age properties and later for quantitating algal blooms.

Unfortunately half of the crack system lies in the wedge tile ro5co2 and the other half in ro4co2. The first tile is taking by a morning satellite pass and the latter as the last of the day. So by the time the composite image is made, too much has transpired on the ground and with passing clouds. Lance-Modis staff has some good ideas on how to fix this but await funding.



 photo terra367random_zps6f93b261.jpg


A-Team, thanks for keeping such a sharp eye on this. I think I'm going to turn this into a blog post tomorrow. I'm now convinced this is unusual, or at least spectacular enough to deserve notice, and looking at the weather forecast it is not going to get better in the coming 5 days (huge high with 1040-1050 hPa pressure over the American side of the Central Arctic). Beaufort Vertigo.

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