The 2014 Melting Season

[Neven]

Jaxa dropped around -150k.

Roughly 80K above 2012 now.

This is a difference with 2012, as back then it was CT SIA dropping hard, and JAXA following.

BTW, is there something wrong with the current ECMWF forecast. I'm in the process of writing the latest ASI update, and I don't want to include a faulty forecast.

[jdallen]

Unfortunately in 2012 in the next 7 days it dropped 720k and this yr has had a hard time putting those #s together in a week. If ice is as thin as believed by many of us it could happen.
Edit: PS party pooper?

Actually, disagree... We are currently dropping over 100k/day with both area And extent on average, m'thinks, for some time.  We may not catch up but weather points towards the melt keeping up.

[Frivolousz21]

I wouldn't use the euro until u see the 00z run.

lots of  sun going in the Laptev Lake.

Expect a big sst spike.

[Neven]

I wouldn't use the euro until u see the 00z run.

Darn it, that was a nice looking forecast to spice up the ASI update... 

I hope it will update in the next hour or so (I never check those XXz times).

[Michael Hauber]

The wedge of open water from Laptev pointed towards the pole is ominous.  Its also interesting to see the East side shows lots of large floes, and the west seems to be mostly broken up too small to see individual floes.  Perhaps this has formed on the boundary between thicker ice from the ESS tongue and thinner ice initially formed in Laptev during winter and then pushed towards the pole by winds and currents. 

Its quite interesting comparing the position of this open water to other years - at minimum.  The ice edge there is already in about the same place as minimum during 08,09 and 13.

[Lord M Vader]

Neven: 12z EURO was a faulty one.. 00z back to "normal"...

//LMV

[Neven]

Neven: 12z EURO was a faulty one.. 00z back to "normal"...

//LMV

Thanks, LMV! Highs still dominating, but a bit less than in the faulty forecast.

[seattlerocks]

If winds are able to displace ice, it means there is momentum transfer, and necessarily heat transfer too.

[jdallen]

If winds are able to displace ice, it means there is momentum transfer, and necessarily heat transfer too.

The danger with ice movement is the import of heat from depth out of the ocean, via ekman pumping.  There is plenty there, and it represents more than sufficient heat to disintegrate the remaining ice promptly, if disturbed.  That's part of what drove the melt in 2012 with the cyclone.

The Euro may have backed off, but there is still very little positive news for the ice.  Looking at Climate Reanalizer again, even with the breakup of the ridge mid-week, the areas which are most vulnerable - Kara and Beaufort - are still under threat.  If the longer range is to be believed, there is rain in volume forecast for both those regions as well, along with others.  Rain in even small quantities will be very bad news for the ice.

Nope, not much of an improvement I'm afraid.  I'm not feeling hopeful for the ice in either the Kara or Beaufort.

[BornFromTheVoid]

Before people get too excited when a huge drop comes of July 1st, the average daily drop from June 30th to July 1st since 2007 has been almost 300k. This is most likely due to algorithm changes to deal with melt ponding and such. Still, if we can maintain losses of >100k for another few days, it means we may actually get another rare mega melt week (>1 million km2 lost in 7 days).

Also of interest, using the 5 day mean, the recent 1 week extent loss of 745k is something that was only achieved once in all June's before 2010. It only been exceeded in June by 3 other years too, 2013, 2012 and 1999. All the more impressive is that it looks like growing in the near term.

[seattlerocks]

If winds are able to displace ice, it means there is momentum transfer, and necessarily heat transfer too.

The danger with ice movement is the import of heat from depth out of the ocean, via ekman pumping.  There is plenty there, and it represents more than sufficient heat to disintegrate the remaining ice promptly, if disturbed.  That's part of what drove the melt in 2012 with the cyclone.

Yes I agree, but my point was simply to illustrate that there has to be air-surface heat transfer if wind is forcing ice movement, because both things come hand in hand.

Apart from very strong (anti-clockwise) storm winds, the HP clockwise winds can be pretty vigorous too, occasionally pulling warmer air from South. The proof of their strength is the ice displacement they cause. And again, if a flow is pulling a solid surface, there *has to* be heat transfer between the fluid and surface too.

Today's map from Navy model illustrates the well-known clockwise ice drift, caused by these winds,



Edit: Thx Neven

[Neven]

Click the button next to the f button in the editor above your comment field (left), to get the img tags, then paste the URL of your image in between the tags:

[Neven]

The latest ASI 2014 update, number 4, is up: High times.

Read it if you want to know everything. 

[Jim Pettit]

Jaxa dropped around -150k.

Roughly 80K above 2012 now.

True. That was the largest JAXA decrease of the "official" melt season. A few more drops like that, and 2014 could slide into third place. It should be noted, however, that 2014 is still above the 2010-2013 average.

Meanwhile, CT area continues to unimpress. It's seen just one century break in the past six days, and only nine so far this month. Compare that to 13 (including one double-century drop) for 2013, and 15 (with four double-centuries) in 2012. 2014 falls further and further behind 2012 with practically each passing day, and is now a whopping 842,000 km2 back. (By this day in both 2014 and 2010, area had already dropped below the 7 million mark. 2014 isn't likely to cross that threshold for another week or so.)

There remains an outside chance that 2014 could set a new minimum record, but that's a VERY outside chance, and it would require near-perfect conditions to happen. (My guess is that 2014's SIA minimum will be no lower than 3.5 million, and could be as high as 4.2 million.)

[Lord M Vader]

For all of you who use to post analysis and forecasts from EURO, I think these maps are more visualizing and easier to look at:





Source: ECMWF.

These maps are public and updated twice a day at 7AM UTC and 7PM UTC.

The color steps at the GPH chart WRT 850hPa temps are in intervals of 4DEG, eg, 0, 4, 8, 12 and so on in Celsius (Also seen on the screen if you scroll down)...

With only two days left of June I think we can rule out that the SIE per JAXA will go below 9 Mn km2 per June 30. In the best case scenario we may eclipse 2011 and lay on a 3rd place. I think it depends on how quickly the ice in Hudson Bay, ESS and Kara Sea disappears now.

Later in the forecast time it seems that the main HP will weaken but not much of cyclonic activity either. GFS 06z is interesting as it in about 1 week strengthens a HP in Kara Sea pushing southerlies to CAB. Given how warm the water in the Atlantic section is, and salty, it wouldnät be good news for the ice...

//LMV

[Frivolousz21]

Jaxa dropped around -150k.

Roughly 80K above 2012 now.

True. That was the largest JAXA decrease of the "official" melt season. A few more drops like that, and 2014 could slide into third place. It should be noted, however, that 2014 is still above the 2010-2013 average.

Meanwhile, CT area continues to unimpress. It's seen just one century break in the past six days, and only nine so far this month. Compare that to 13 (including one double-century drop) for 2013, and 15 (with four double-centuries) in 2012. 2014 falls further and further behind 2012 with practically each passing day, and is now a whopping 842,000 km2 back. (By this day in both 2014 and 2010, area had already dropped below the 7 million mark. 2014 isn't likely to cross that threshold for another week or so.)

There remains an outside chance that 2014 could set a new minimum record, but that's a VERY outside chance, and it would require near-perfect conditions to happen. (My guess is that 2014's SIA minimum will be no lower than 3.5 million, and could be as high as 4.2 million.)

That is all because of melt-pond in the central arctic basin not forming yet.

I think you are making a huge mistake. I think area will be 3.1 mil give or take 100K.

If you think  SIA will be 3.5 mil to 4.2 mil then you also must think Jaxa will be 4.8 mil(2013) to 5.5 mil(2006).

 
2013 passed  2010 in area in twenty days after being ahead by 1 million.

NSIDC single day dropped  -250K today. Well see how area does .

[Frivolousz21]

only -102K in area because of the lack of melt ponds over the Central arctic basin which is  161.5K above normal.

Need two big drops  the next two days to reach my goal.
Either way I expect area to fall hard shortly.
Good times.

[Frivolousz21]

This is getting funny. 

[Frivolousz21]

Help me out folks How is 2010 so  much lower?

 2010 is roughly -900K  below 2014 in that coparison

[Buddy]

Good question.  From those visuals.....I could make a case for just the opposite (central/north Russian coast has less ice than 2010.....northeasters coast of Russia also has much less ice now.....and Baffin Bay has less ice now than in 2010).

Again.....good question....

[Frivolousz21]

that 2010 CT image is AMSRE.

Why would they archive it like that.

[Bruce]

Help me out folks How is 2010 so  much lower?

 2010 is roughly -900K  below 2014 in that coparison

Look at the whole stretch from Greenland to Svalbard to FJL to NZ and into the Kara -- 2014 ice is pushed much further south that 2010. The Beaufort was more open in 2010, too. I don't know the numbers, but maybe that makes up for the areas where 2014 has less than 2010.

[Frivolousz21]

 The 2000-2011 images are Amsre.
2012 on are SSMIS on CT

[ChrisReynolds]

       250k drop on NSIDC Extent!       

Not the first 250k drop (15 June), but when you look at it in terms of the recent pattern, attachment 1, it is striking. Wipneus notes it comes from Hudson/Baffin & Greenland. Will we see a decline in losses when Hudson/Baffin are clear of ice? I suspect that the Arctic Ocean is being preconditioned and as long as the weather holds the losses will continue.

Attachment 2 takes a bit of explaining. It shows NSIDC Extent for 2007 to 2013 relative to 2014. Simply it's the plot of the difference between 2014 and each years 2007 to 2013. 2013 is clearly between the lowest years and the rest, and could feasibly gain on the lowest years.

I doubt my CT Area prediction, since making it I've had a nagging doubt that CT Area losses will be well above average as this season progresses and this year the method will fail. That depends on whether the current weather conditions will hold. As far as a week from this Monday both GFS and ECMWF show broadly high pressure dominant conditions.

[Frivolousz21]

Chris,

I think your 3.0-3.3 mil km2 is pretty spot on.

[Frivolousz21]

Can  anyone help me find CT data? 

Snow and ice data provided by the National Center for Environmental Prediction/NOAA, NSIDC, U. Bremen

probably where the AMSRE data came from?

If they used amsre between ssmis data there is no way they are compatible.

any info would be great

[Neven]

Can  anyone help me find CT data? 

And why 2000-2011  i       

Friv, there's a link on the ASIG, and you can download my spreadsheet from Google Drive (see latest ASI update on the ASIB).

[jdallen]

It looks like Nares ice is disintergrating:

[jdallen]

Ice in the Petermann fiord looks pretty unstable as well.  I wonder if instability is arising because of subglacial flow of warmer water into Nares and the approaches to the Lincoln sea?  Thoughts?

http://map2.vis.earthdata.nasa.gov/imagegen/index.php?TIME=2014180&extent=-384224,-971712,-184544,-847296&epsg=3413&layers=MODIS_Terra_CorrectedReflectance_TrueColor,arctic_coastlines_3413&format=image/jpeg&width=780&height=486

Edit:  the blog didn't like me embedding the image.  URL instead.

[Peter Ellis]

Looking at the most recent IJIS monitor, here:
http://www.ijis.iarc.uaf.edu/cgi-bin/seaice-monitor.cgi?lang=e

Something is very strange in Hudson Bay - about half the remaining ice seems to vanish overnight (06/28 to 06/29).  Looking at the RGB plots, I think the ice is getting wrongly removed along with the clouds over it.  This means that tomorrow's IJIS extent may well show a huge (but unreal) drop, which will bounce back in the next day or so.

[Siffy]

Looking at the most recent IJIS monitor, here:
http://www.ijis.iarc.uaf.edu/cgi-bin/seaice-monitor.cgi?lang=e

Something is very strange in Hudson Bay - about half the remaining ice seems to vanish overnight (06/28 to 06/29).  Looking at the RGB plots, I think the ice is getting wrongly removed along with the clouds over it.  This means that tomorrow's IJIS extent may well show a huge (but unreal) drop, which will bounce back in the next day or so.

I'm not sure it's wrong. Looking at a nearby area air temperatures are well above 10C

Temperatures around Hudson Bay are extreem also. The 33.4 C at Fort Severn might seem to be a glitch in the sensor if it wasn't for the 33.1 recorded at Peawanuck and the 32.6 from Moosonee At James Bay. For our American friends the above temperatures are all in excess of 90 F, not what is expected from polar bear country.


At Churchill:
2014 - 6/28 30.7 C
2013 - 6/23 27.9 C
2012 - 6/25 25.0 C


In 2012 high island temperatures in the CAA were apparently responsible for melting large quantities on MYI in the channels. I don't think a repeat is out of the question.
Terry

Caribou River park reserve area is supposed to be hovering around 15C ish which is to the west of Hudson bay.

If there is north flowing wind dragging that hot air into the Hudson you'd get phenomenal melt out surely?

[Frivolousz21]

It's probably temp brightness effected by the super torch.

Either way ice ice is vanishing in the basin fast enough as is that 2014 is plummeting.

Once again with the large ridge and anti cyclone water is opening up fast in the Beaufort, ESS/Chuchki, the Laptev is absurd and really sunny.  EC shows 2-4c there widespread.  That shallow shelf warmth will get driven into/under the ice further North and cause quick melting.

Hopefully ijis foks correct the Beaufort issue even tho the ice is about gone any how

[Greenbelt]

Looking at the most recent IJIS monitor, here:
http://www.ijis.iarc.uaf.edu/cgi-bin/seaice-monitor.cgi?lang=e

Something is very strange in Hudson Bay - about half the remaining ice seems to vanish overnight (06/28 to 06/29).  Looking at the RGB plots, I think the ice is getting wrongly removed along with the clouds over it.  This means that tomorrow's IJIS extent may well show a huge (but unreal) drop, which will bounce back in the next day or so.

Currently (7pm EDT Sunday the29th) 21 degrees C at Sanikiluaq, NU

https://weather.gc.ca/city/pages/nu-29_metric_e.html

https://www.google.com/maps/place/Sanikiluaq,+NU/@56.5852885,-79.1907981,5z/data=!4m2!3m1!1s0x4da42bbe84bdcb37:0x855e04202555ce91

[Bruce]

It looks like Nares ice is disintergrating:

Yeah, I saw that little crack appear way up channel a day or so ago, but I never expected all the ice in-between to just explode like that.

Aside from it's job holding back the Greenland glaciers, doesn't the ice in the strait hold back a fair bit of the thickest, oldest MYI in the CAB?

[Bruce]

Big crack report, June 29 edition: The big crack is turning into something else. In the upper left of the image, strands are branching off of the main crack, and shredding -- absolutely shredding -- the ice. From the midpoint of the image down, several en echelon strands have formed, and the older branch has opened up. The small crack north of Greenland (second pic) has opened up since yesterday.

It doesn't seem like the even the MYI has much strength to it. One good storm and we're going to see the world's biggest slushie (kelp flavored).

[jdallen]

Looking at the most recent IJIS monitor, here:
http://www.ijis.iarc.uaf.edu/cgi-bin/seaice-monitor.cgi?lang=e

Something is very strange in Hudson Bay - about half the remaining ice seems to vanish overnight (06/28 to 06/29).  Looking at the RGB plots, I think the ice is getting wrongly removed along with the clouds over it.  This means that tomorrow's IJIS extent may well show a huge (but unreal) drop, which will bounce back in the next day or so.

I'm not sure it's wrong. Looking at a nearby area air temperatures are well above 10C

<snippage>

Added threat - rain sweeping across the entire bay.  There's an awful lot of energy being dumped directly onto what is very badly broken up ice.

[TerryM]

Bruce
Nares advects ~.10 of the Arctic ice that heads south, but as you say it's the thickest oldest ice that exits through Nares.
I don't think we break any records without Nares being open for a good part of the season. In 2012 the CAA opened and MYI was melted away there that otherwise would have been spinning around the gyre for years. 2012 fundamentally changed the Arctic, I think[size=78%]
Possibly next year with both Nares open and warm islands in the CAA to melt and advect MYI we'll see a virtually ice free arctic. If not next year, soon.
Terry

[/size]

[Bruce]

Hi Terry,
Thanks. That's a lot of ice for a narrow channel -- and if the ice fragments like it has in across a lot of the arctic, the amount could go up (even if the proportion doesn't).

I agree with you about 2012 but, as I said recently, 2013 was significant too. It was well on its way to breaking records when the conditions changed at the end of the season, and its numbers ended up unremarkable (for the new normal). But I believe that it did a lot of damage that didn't show up until now (though the warm winter had its effect, too.) We're seeing a lot of early melt this year, despite the relatively benign weather. If we get a couple of weeks of really melt-worthy weather, it seems like the whole thing is going to fall apart (and what are the odds that we won't get a couple of weeks over the next two months? It could happen but, as you say, that just puts things off for a year or two.)

It seems like a lot of people here sense it. I'm new to this forum, but I've been following the cryosphere closely for a few years. Things just feel different now. Like we've entered the terminal phase of the death spiral. We all know now that it is inevitable; it's just a matter of when, not if.

It's tragic. The north used to be a place of unspoiled wilderness. A place where nature still thrived, mostly unspoiled by civilization. Now we've killed it without even trying. What does that say about us and our future?

[Frivolousz21]

From ice bridge this year.

I don't think the Earth is warm enough to melt out the arctic yet and it may be decades before it happens.

Getting rid of that area of ice with all that snow built up on 3-4M+ of MYI is impossible to melt currently, impossible to advect in any appreciable amount where melt could make up the difference.

I think it will require April and May in the arctic warming quite a bit more and total removal of snow cover on either side of the arctic at least 1-2 weeks earlier then the current records for snow melt.

We have only seen ice like that melt out during a season in the 70-75N range in the Beaufort region thru amazing bottom melt because of atmospheric conditions that can not be replicated North of GIS and parts of the NA side.

[Bruce]

I don't think the Earth is warm enough to melt out the arctic yet and it may be decades before it happens.

Friv,
I don't think 100% of the ice has to melt, any more than the arctic has to become the Caribbean, to make this a done deal. Once the ice hits 20, 15, 10 percent of the former ice cap, it's over; the proverbial fat lady has sung.

I used to think that that day would look like a dense pack of MYI desperately clinging to the CAA, holding out in it's last redoubt against the angry sea. But as my semi-tongue-in-cheek "big crack reports" suggest, I now believe that when we next get to that point, the whole thing will probably break off and disintegrate. We'll be left with a few stubborn floes wandering around a big empty ocean.

[Bob Wallace]

I don't think the Earth is warm enough to melt out the arctic yet and it may be decades before it happens.

We're seeing a strong trend here.  What might stop it and stretch the meltout decades into the future?  I'm watching a car plunge over a cliff and Superman isn't in sight....

[jdallen]

I don't think the Earth is warm enough to melt out the arctic yet and it may be decades before it happens.

We're seeing a strong trend here.  What might stop it and stretch the meltout decades into the future?  I'm watching a car plunge over a cliff and Superman isn't in sight....

We're arguing over the placement of deck chairs after hitting an iceberg

I agree it will be a long time to an "ice free arctic".  However, behavior to me implies the "tail" to that eventual outcome may be thinner than we think, with de rigeur summer reduction of the pack to under 1.5 million KM2; further.  I think that could happen within the next decade.  Unfortunately, that will mean a more definitive transition to vastly different climate in the northern hemisphere over all, which everyone I think will find profoundly unpleasant.

Regarding Nares - I concur with Terry - the effect is asymmetric in as much as it's the thickest, oldest ice that gets sucked through the straight.  I'm thinking the effect is indirect as pointed out - ice exiting Nares makes space in the CAB, which makes the ice more vulnerable to attack from multiple directions.

[Frivolousz21]

I don't think the Earth is warm enough to melt out the arctic yet and it may be decades before it happens.

We're seeing a strong trend here.  What might stop it and stretch the melt-out decades into the future?  I'm watching a car plunge over a cliff and Superman isn't in sight....

The arctic has stopped warming at least since peaking in 2011 overall.  Other contributing factors to the huge drop off post 1996 could be in part from the AMO.  I am not a believer in the AMO as anything substantial but it's a potential impactful thing if it is real since it correlates big time with post 1996 land, sea, snow loss over the NH in Spring and Summer.

But again for me it's mostly about the amount of energy it takes to melt that thicker ice reserve.  How do we get to the point where that ice is exposed to that kind of energy.

We haven't even melted out the Canadian Archipelago yet which is directly connected to land masses that bring way more heat to that region then can be generated in the Southern arctic basin.

We have never had a season where all the FYI ice melts out.  Not even 2012.  I just think we are a long way off because we need the arctic basin to open up weeks earlier then it has so far. 


If that last 2-3 mil km2 of area wasn't the thickest oldest ice that is covered in a thick layer of snow then no biggie.  But the arctic hasn't shown the kind of warming required to accomplish this.  Nor has the amount of snow in Spring loss required to warm the cryosphere before we blow thru t much insolation.

I used to think we have a shot at an ice free arctic by 2020(1 mil km2) or less.  But moved it back to 2021-2025.

Here is one of my reasons.  buoy 2014D. While there has been plenty of time above 0C + sunshine at some points this Summer almost zero melt there at all.  There is a large area of ice like that ice as thick or thicker that is going to be extremely hard to displace/melt IMHO without a lot more energy entering the system.

http://imb.crrel.usace.army.mil/2014D.htm



There is "apparently" a large area of thick ice out there.



But this area of ice "apparently" almost melted out completely in 2011 and 2012 then recovered back to the current 2014 levels? 

Not sure what to believe when it comes to this stuff.  Was ice bridge around to confirm that old ice really vanished in 2011 to only be less effected in 2012 and make a complete recovery in one year?  like wtf?

[Frivolousz21]

The GFS has backed off from cooling the arctic down as much as it was showing and it's struggling to break the HP bondage in the arctic.

The Canadian Arctic Basin will probably see some strong bottom melt commence over the next couple of weeks. 

As you all know we can see incredible bottom melt rates in July and August and since most of the ice there is 2M or thinner.  It won't take much once it kicks off in earnest to destroy parts of the Canadian Basin.

[Neven]

Aside from it's job holding back the Greenland glaciers, doesn't the ice in the strait hold back a fair bit of the thickest, oldest MYI in the CAB?

I used to think that too that sea ice holds back glaciers like Petermann, but then realized the glacier is several hundreds of metres thick, whereas the sea ice is at most 5 metres thick.

[jdallen]

Aside from it's job holding back the Greenland glaciers, doesn't the ice in the strait hold back a fair bit of the thickest, oldest MYI in the CAB?

I used to think that too that sea ice holds back glaciers like Petermann, but then realized the glacier is several hundreds of metres thick, whereas the sea ice is at most 5 metres thick.

Imagine a man trying to prevent a 100 ton semi trailer from rolling down a 15% grade by pushing it back up hill, and I think you capture the maximum possible resistance sea ice can provide against the Petermann.

[Frivolousz21]

The Euro slowly breaks the pattern down before pretty much bringing it back but in more force.

I am not saying it's a bad weather regime on this run the entire way thru.  But it's not very good overall.

The Euro ensemble mean has upped the anomalous ridging as well after a brief respite from it.

[Frivolousz21]

Weird how having coastal zones masked out DMI plummets like the rest.

There new product shows an incredibly higher amount of ice. 

Ironically Jaxa updated last year because of over estimation coastal ice.

I don't understand how it's an improvement if the new product is worse then norsex is when compared to Jaxa, bremen, and NSIDC?

I am guessing we are about to see a plummet on their new product? 

[Peter Ellis]

Coastal masking isn't the only difference: the more recent chart uses a threshold of 15%, while the older chart used a threshold of 30%. In their dataset , most of the remaining Hudson Bay ice has just tipped under the 30% threshold, explaining the main difference in shape between their two graphs.
http://osisaf.met.no/p/ice/nh/conc/imgs/OSI_HL_SAF_201406291200_pal.jpg

IJIS seems to be missing most of that ice today, presumably due to a difference in sensor and/or algorithm.

[Frivolousz21]

Coastal masking isn't the only difference: the more recent chart uses a threshold of 15%, while the older chart used a threshold of 30%. In their dataset , most of the remaining Hudson Bay ice has just tipped under the 30% threshold, explaining the main difference in shape between their two graphs.
http://osisaf.met.no/p/ice/nh/conc/imgs/OSI_HL_SAF_201406291200_pal.jpg

IJIS seems to be missing most of that ice today, presumably due to a difference in sensor and/or algorithm.

Right.  But compared to Bremen, Jaxa, Norsex, and NSIDC it has 2014 almost tied with 2013.  Every other one isn't like that.

Maybe they have a long running average or something.  They show 2014 about 11 million km2 while Jaxa is almost 2 million lower and if we throw out the Hudson thing which is only about -100K extra it's still about 1.7 million lower.  NSIDC is 1.2 million lower(NSIDC is typically higher then Jaxa because it uses horrible SSMIS resolution.  Bremen which uses a 5 day running average is about 1.4 million below the DMI chart.  The big drops have occurred on NSIDC and Jaxa within that window so Bremen will drop a bit sharper the next few days.

It's even 1.1 million above Norsex which uses SSMI 25km spatial res. So it's not just the Hudson.  Maybe they are counting absolute extent and not 15% or higher.  Either way it's out of sync with every other product.