The animation on the right consists of NSIDC
sea ice concentration maps, one for each ASI update.
Check out the Arctic Sea Ice Graphs website (ASIG)
for daily updated graphs, maps, live webcam images and
the Arctic Sea Ice Forum (ASIF) for detailed discussions.
August 18th 2013
In the past two weeks sea ice decrease has been chugging along happily, with that huge area of low concentration ice still staring us in the face. All melting season long I've been expecting massive losses after the cyclones did their churning act on the large patches of first year ice, but they have failed to materialize. The loss is there, but it isn't massive.
Apparently the cold and cloudy conditions the cyclones brought in from May onwards, have been enough to compensate for the churning of the ice pack, that was never really preconditioned by a sunny start to the melting season. And so 2013 has remained part of the group of slow years and didn't come any closer to the group of record years.
This melting season has been a great and humbling teacher so far, but there's still a couple of weeks left.
Sea ice area (SIA)
I've been waiting all day for the Cryosphere Today SIA data to be updated, but as none are forthcoming, I post the graph with data up to August 15th:
After the crazy uptick that was described in the previous update the trend line has resumed dropping again, battling it out with 2009 and 2010 right now. It's still over 1 million km2 behind 2012, and around 850K and 700K behind 2007 and 2011 respectively. If this year follows the 2010 pattern (and 2010 was a year with a very patchy ice pack as well) it might still get somewhat close and perhaps overtake 2008.
Here's the link to my updated CT SIA spreadsheet.
The SIA anomaly has dipped below the -1 million km2 mark again:
Sea ice extent (SIE)
IJIS hasn't reported any data either today, so here's their SIE graph up until August 16th:
With a century break reported for the 16th (might be revised, once data gets reported again) the trend line is making a small swoop towards the big melt years, but is still massively behind here as well. Nevertheless, if it can keep up this tempo, it might creep a little closer to 2007 and 2011 towards the end of the month.
Here's the link to my updated IJIS SIE spreadsheet.
Cryosphere Today area per IJIS extent (CAPIE)
CAPIE percentage is still way above that of last year. We've discussed it a bit more on the forum, but most agree that this is due to melt ponds getting frozen over in this year's cold temperatures, which were much less pronounced last year:
If the difference were just 2-5% I would agree that melt ponds explain the difference (remember, there has been a lot of divergence going on this year, making the ice pack less compact), but 10% is a bit too much in my view. Perhaps increased cloudiness is making it harder for sensors to pick up all those small holes in the pack's interior, or maybe they don't get counted either way because resolution isn't high enough. However, the exact cause of the discrepancy between 2012 and 2013 - probably a bit of everything - is hardly relevant.
For a thorough explanation of what CAPIE is, read the CAPIE subsection in this ASI update. Here's the link to my updated CAPIE spreadsheet.
Regional SIE and SIA
Regional graph of the week, taken from the Regional Graphs page:
The channels and leads between the islands of the Canadian Archipelago have been slow to melt out this year as well, but the melt has picked up in the last two weeks, as can be seen on this map that Wipneus has custom-made for this ASI update (based on Uni Hamburg data, see here), showing the differences that have taken place since the previous ASI update. Red = ice two weeks ago, open water now; blue the other way around:
The southern route of the Northwest Passage has now opened up, but it still remains to be seen if the main passage will open up. With a blot of persistent ice blocking the Northern Sea Route over at the Severnaya Zemlya Islands, we could be looking at the first melting season with neither of the two passages opening up in a long time.
Sea Level Pressure (SLP)
The two-week animation of Danish Meteorological Institute SLP images tells us a bit about the weather in the Arctic in the past fortnight:
We see how the third storm gets into play, rages for a day or three and then quickly disappears again. The dipole anomaly set-up, with a high over the Beaufort Sea, also didn't last long and so no accelerated sea ice loss was observed on the Pacific side of the Arctic. In fact, towards the end of the animation, the dipole is replaced by a reverse dipole, with a high-pressure area over the Siberian side of the Arctic, mirrored by a low-pressure area over the American side.
How this is going to develop, can be seen on the the 6-day weather forecast from the ECMWF model (click for a larger version):
The reverse dipole remains in place for the week to come. Traditionally, this would mean a very slow rate of ice loss, but perhaps that sunny conditions on the Siberian side of the Arctic and compacting winds can still take a bite out of that low-concentration patch that extends well out towards the East Siberian Sea. If this comes about, the rate of decrease could remain stable.
Temperatures
Compared to the map from two weeks ago, the cold over the Arctic Ocean has spread out and intensified over the Arctic Ocean:
Air temps north of 80° are extremely low for this time of year, according to the DMI 80N temp graph:
There are definitely no more melt ponds in the central basin, and leads between floes are probably also starting to freeze over. What this means for the hole in the ice pack, close to the North Pole, that has been asserting itself more prominently in the past week, remains to be seen.
Sea surface temperatures on the DMI SST anomaly map also seem to have gone down a bit, compared to two weeks ago, with a patch of cold water developing near the Bering Strait:
Here's the map from August 25th 2012. There's a marked difference in the Beaufort Sea on one side, and the Kara Sea on the other.
Conclusion
Mid-melting season it became clear that beating 2012 was going to be a tough proposition (100% impossible now), but it looks like 2007/2011 and even 2010 might be out of reach. Given the hundreds of thousands of square kilometres that need to be made up to come close to the Top 3, combined with the weather forecast, I don't think much is going to change, but never say never in the Arctic. There's still quite a bit of melting potential out there, though not much melting potency.
To be honest, I'm still a bit surprised at that. With the record amount of first year ice at the start of the melting season, and lower maximum volume, and a spectacular cracking event causing the Beaufort Sea to fill up with additional thin ice in leads, I thought that there's was a good chance that for the first time we would be seeing back-to-back melting records.
But it all turns out differently, and so instead of new records we see the traditional regression to the mean. This is a careful first conclusion, but I'll have more on that, of course, when the melting season officially ends, 2-4 weeks from now.
Damn you Neven!
We've obviously been thinking similar things but you beat me to pressing the 'post' button. ;)
Posted by: Chris Reynolds | August 18, 2013 at 20:37
That's your punishment for not using the ASIG page! Hope you saw some good films today. ;-)
Everyone, here are Chris' similar thoughts.
Posted by: Neven | August 18, 2013 at 20:45
Great post, thanks Neven!
The feature of this update should be the 80N temp, as I have not seen anything like it in the record at DMI. It could possibly mean that even if we have had more normal cyclone activity, that other weather elements have assisted as well, even if e.g. the AO index has flipped a number of times during the summer.
Or perhaps the 80N average temp is such an arbitrary and unreliable piece of information that it does not mean much..
Posted by: John Christensen | August 18, 2013 at 21:15
Hi neven, I've been watching your blog for some time and I really love it. You do an absolutely fantastic job. Have any of you noticed the ridiculously cold temperatures in Northern greenland in recent days? I think most of the dmi 80N stuff originatates from record breaking temps on the northern coast. The trouble is, this seems a very unhelpful place for cold weather. The ice was never going to melt there, wheras some of the siberian/atlantic stuff could.
Posted by: QuantumOverlord . | August 18, 2013 at 22:23
Could someone please explain why a cyclone makes the Arctic colder. I associate cylcones with low pressure warm air.
Posted by: Bob Bingham | August 18, 2013 at 22:50
Looking at the DMI North of 80 temps for the past 56 years, I would say this has been the coldest arctic summer (North of 80) in the past 56 years.
I don't have any elaborate theories, I believe it is just natural variability. Everybody that lives in the mid latitudes, can remember being ripped off by a cool rainy summer. For me it was 2007, a few years latter it was southern Ontario with a pesky upper level Hudson Bay Low that spun around all summer, bringing cool showery weather. Last year it was Great Britain turn, with one low right after another; all summer long.
This year was the Arctic's turn for a crappy summer.
Despite all this bad luck, the ice will finish between 4th and 6th place, which is amazing.
If we had a normal year, 2013 would be in competition with 2012.
If we had a year like 2007, the ice would be close to being wiped out.
Come spring 2014, the slate will be wiped clean, as much of the ice that did not melt is flushed out of the arctic.
The odds of having another year like 2013 is rather small, so next year the horse race will once again be to vie for a new minimum.
Posted by: Lord Soth | August 19, 2013 at 00:22
Lord Soth, I think you have the right of it.
Bob B., polar cyclones are fundamentally different from the tropical variety, and are a species of 'cold-core' system:
http://en.wikipedia.org/wiki/Cold-core_low
Posted by: Kevin McKinney | August 19, 2013 at 00:43
Bob, is easy, the sun is up 24 hours a day during summer, any extensive cloud coverage would cool things down, winter offers the exact opposite, Infra Red from the sea gets bounced back by the clouds, there is less great deal of cooling from photons (IR) escaping to space.
Lord Soth, cold is relative to the effects from the *high* sun if allowed to shine to the surface, a cloudy North Pole now keeps it warm. The sun at the North Pole is 12.8 degrees above the horizon, hardly a fantastic heat source. Yet there is a whole lot of open water around there. Someone should come up with a sea ice area number based on no thresholds, just evaluate the entire surface of open water pixel by pixel if need be.
Posted by: wayne | August 19, 2013 at 01:09
What the consequences was of bits of open water in the high Arctic (e.g., north of 80N). As Arctic surface water with ice cover is about -1.7C, does the open water in leads and small polynyas cool the lowest two meters of air (thus the very low DMI temps)? Recent years have had slightly lower DMI high Arctic summer surface temps than the long-term average. Might bits of open water cause this (or at least influence this)? This year has much more highest Arctic open water, so is this why DMI temps have plummeted?
I understand the heat transfer between the Arctic surface (all Earth surface, actually) and (ultimately) outer space is happening all year 'round, only being offset by solar gain during the day (especially the long Arctic 'day' we call summer). How does this support or conflict with the idea in my first paragraph?
Posted by: Tor Bejnar | August 19, 2013 at 01:29
Wow, looks like my prediction of a rebound year (due to no prior two years running in a row for new minimum records, and no previous periods of more than three years running of lower minimums, e.g. 2010,2011 & 2012) will come to pass as a gross understatement, with 4.35 guesstimate bowing to a higher number next month. Add to that 2008 was a rebound year after 2007 mirroring 2012/2013. No dead cat bounce or Fram Strait wash out. My surprise is how much of a rebound - wow!
Posted by: Hans Gunnstaddar | August 19, 2013 at 02:02
Neven,
Just catching up on things I've been recording all summer and not getting the chance to watch. Hardly touched the backlog though.
Posted by: Chris Reynolds | August 19, 2013 at 07:41
Ellesmere Island is currently covered in snow, as is the north coast of Greenland. These areas were bare rock this time 2010-2012 (all I've bothered to check in MODIS).
From my memory of previous seasons it does take a while from snow at sea level to sea ice formation, so I don't think we'll see any ice formation in the near future, but early signs that we may see an early freeze.
Posted by: Michael Hauber | August 19, 2013 at 08:23
@Tor on DMI 80N average temperature,
You could have a point; it is odd how in the 60s and 70s the summer temp would be very stable and a bit warmer than now, when the ice cover and ice concentration at and around 80N was considerably higher, so the cooler summer temps in recent years could be the heat exchange between sub-zero temp water and the air above and around leads.
This year saw both leads, holes, combined with lower overall temps due to the cyclones, so was possibly the best combination to create record low 80N temps.
Posted by: John Christensen | August 19, 2013 at 08:24
@Tor:
The recent DMI 80N average temperatures are too low to be explained by this, as they're well below -1.7C. A low pressure system centered in NW Greenland/Ellesmere had been pulling very cold air north off of Greenland, over almost completely frozen sea ice, and direclty over the well-instrumented "North Pole Webcam" area, yielding temperatures down to ~-8C. At roughly 84N, 0E, this area is only around ~320km away from Greenland. There is still a lot of open water above 80N on the eastern side, including at the pole, but not between Greenland and the "North Pole Webcam" sensors. The DMI 80N temperature has already jumped back up much closer to normal as the low pressure drifts southwest.
You're right that ocean water will be colder than melt ponds. -1.7C is for ocean-normal salinity, so it's a little warmer, but not much. This effect is too small to produce the observed DMI 80N temperature changes, however. I think most of the long-term trend in DMI 80N temperature is due to increased data coverage forcing corrections which reduce errors in the modeled analysis product which it is based on.
@Neven:
The real opposite of a dipole pattern is an annular pattern, not a reverse dipole pattern. A reverse dipole pattern will likely have even greater volume loss than a dipole pattern, although it will cause spreading towards the Pacific, so much of this will not be apparent in the extent numbers until a later compressional phase. We have very thin ice near the pole, near Severnaya Zemlya, and in the Eastern Siberan sector. Severnaya Zemlya and the Eastern Siberan sector in particular have had persistent cool onshore winds all year due to winds sweeping aroud the Russian high pressure system, but nevertheless still have very thin ice due to their low latitude. They're forecast to finally get some warm offshore winds, and should melt out significantly. On the other hand, Beaufort melting should nearly stop, and the CAA has a good chance to even reverse.
The nortwestern CAA channels (west of Ellesmere and north of the Parry Channel) have thin ice and have been breaking up very quickly, and I think we'll see most of the fast ice in them break up, leaving running ice.
As usual, there's been a large bubble of warm Pacific water north of the Bering Strait all summer, and if anything it looked a little larger than normal. It has cooled way too quickly to be heat loss. The cold anomaly has to be just it being capped by fresher Arctic water earlier than normal, taking more heat down with it than usual. The normal freshwater pool north of Eastern Siberia has been getting quite big lately, and I'm wondering if we're going to see odd things start happening because of this.
Posted by: Blaine | August 19, 2013 at 11:31
I still think we will drop to around 2011 on jaxa.
Very strong winds are pounding the ice on the Eastern side centered over Franz Josef Land. This is foreasted to continue for days on end.
The ice edge has already been nailed back to near 84N.
3-4 days in a row of long fetch warm Southerly winds will push it back close to 85N and it will meet up with the large open water areas and allow further encroachment of the warmer water that is right up against the ice sheet.
The ice in the Laptev region is all toast there is a large area of open water in the middle of it that has been skewed from the sensors quite a bit.
The ice is a wreck all the way up to the ESS and Chuchki essentially along the PM through the pole.
With high pressure forecast to sit over the Laptev and ESS the next 7-10 days I think we will see steady opening of water here.
Winds are forecast to blow hard from the Chukchi through the Southern half of the ESS and push the ice in the ESS towards the Russian coast where there is warmer water. The winds will be blowing off of even warmer water in the 2-6C range.
Essentially three sides of the ESS is exposed to open water that will help aid in melt when the ice is being shuffled that hard around in it.
Posted by: Chris Biscan | August 19, 2013 at 13:37
"I think most of the long-term trend in DMI 80N temperature is due to increased data coverage forcing corrections which reduce errors in the modeled analysis product which it is based on."
One of the caveats of this product is that there are known long-term biases due to development of the reanalysis software. So, quite possibly.
Any thoughts on the role of evaporation/condensation in affecting the near-surface heat fluxes?
Posted by: Kevin McKinney | August 19, 2013 at 14:50
Very cloudy and a little sun over the summer in the Arctic and very hot weather in Europe is probably the reason for the relatively cold weather up north. It all about ying and yang!
Posted by: Espen Olsen | August 19, 2013 at 15:52
Hi,
I don't normally post in the blog much as I don't feel I know enough to add to the conversation when we are talking about the specifics of the ice so I just read here and hang around over at the Forum. However, I have a comment/question today (which will probably show why I don't post here much).
It relates to Lord Soth's comment.
"Looking at the DMI North of 80 temps for the past 56 years, I would say this has been the coldest arctic summer (North of 80) in the past 56 years.
I don't have any elaborate theories, I believe it is just natural variability...."
Kevin seconded this comment. But doesn't this metric need some further discussion beyond being automatically attributed to natural variation?
There have been untold numbers of discussions over the last few years about how 'weather' events have been juiced by AGW. Just in recent months we have had extraordinary cold and rain in many parts of the world (US Midwest a couple of times, US south, Russia) as well as extreme heat and drought. Many of the discussions related to those events have focused on how climate change is strongly influencing those extreme weather events.
Does it not follow that the very unusual cold temperatures north of 80 deg could also be significantly influenced by the very unusual weather patterns being generated by our rapidly changing climate. Some of the wild fluctuations away from historical norms will actually not be to the hot, wet and dry sides of the records but occasionally (rarely) to the cold side as well.
Does this make sense?
JimD
Posted by: James Dunlap | August 19, 2013 at 17:40
I am still wondering if the smoke from wildfires (they started early this year?) is shading the ground up north - leading to the low 80N temps. Smoke might also heat the atmosphere up higher which might reduce the differential temperature north to south, trapping the warm air to the south?
Posted by: Mike Constable | August 19, 2013 at 19:37
http://www.foxnews.com/science/2013/08/19/russian-meteor-explosion-atmosphere/
‘Russian meteor created new 'dust layer' in stratosphere, researchers say’
I don’t very often link a news article from Fox News, but in this case they seem to have the latest on a meteor that exploded over a Russian city in February (presumably this year, because the article does not specify - it just states in February.
Pasted from the article: - Masked in the chaos, however, was an enormous plume of dust that the Russian meteor left behind in Earth's atmosphere. This cloud, which had hundreds of tons of material in it, was still lingering three months after the Feb. 15 explosion, a new study has found.
- The Russian meteor, which weighed 11,000 metric tons when it hit the atmosphere, detonated about 15 miles above Chelyabinsk. The explosion sent out a burst of energy 30 times greater than the atom bomb that leveled Hiroshima during World War II.
- "Indeed, we saw the formation of a new dust belt in Earth's stratosphere, and achieved the first space-based observation of the long-term evolution of a bolide plume," Gorkavyi said in a statement.
Could this dust have blocked enough sunlight to have changed the weather in the Arctic this Summer?
Posted by: Hans Gunnstaddar | August 19, 2013 at 20:52
Interestingly enough the southern UK has had its first decent summer since the melt started in earnest in 2007 or so. Maybe the weather conditions have changed this year. Any thoughts on the summer where everyone else is?
PS in your poll I reckoned on a less than severe melt this year. Just wait till WUWT wakes out of his coma!
Posted by: john_mann | August 19, 2013 at 21:20
While I'm still hoping that we get a nice cold fall and a reprieve from an ice free Arctic for a couple more years, I think anything still can happen.
The DMI sea surface pressure map is showing wind from the Barents Sea straight across the Arctic to the Bering Stait. Who knows what a warm strong wind from Europe might do to the ice pack if it persists for a few days ...
Not saying 2013 is going to break any records, but it might break a few hearts.
Posted by: NLPatents | August 19, 2013 at 21:55
john and Hans: Here in MN, we have had a late spring and a cool-ish summer. A dust cloud could help explain that.
If I were a bit more paranoid, I might suspect that the whole thing was some kind of geo-engineering experiment set up to look like a bolide event.
But I'm not that paranoid...
Am I???
Mike, we have also had haze from fires out West and in Canada. I can't judge what the relative effect of dust from a bolide versus smoke from massive fires might be.
Posted by: wili | August 19, 2013 at 22:17
alert wili knows about the 'experiment'.
Initiate alpha one zero! Now, do it now!
Posted by: Pete Williamson | August 19, 2013 at 22:23
John_Mann,
Same story in Ireland, we had a scorcher in July, very high temp for >3 weeks (pretty long for us) but no records broken. August is pretty acceptable - overall best summer since mid-naughties.
Like yourself, I reckoned on a 4.5m m^2 this year - it may still squeak down to that, but I am reckoning on a 4th or 5th lowest ever. A pallid "recovery" like 2008 and 2009, but ultimately only a dead cat bounce.
This year has shown the Arctic has more resilience and variability that we thought, though not as much as deniers have been claiming.
Posted by: toby | August 19, 2013 at 22:44
@ Hans That was the meteor that crashed this year in Russia. Got a lot of play because of the number of videos. As far as the dust cloud is concerned. May influence local, but the cloud was very minor compared to most volcanoes that erupt every year and do not have much impact. I one has been looking at the erratic jet stream this year there have been blocking patterns in it all year long.
The amazing thing to me as that despite having weather that should have meant minimal melt in the Arctic, we still have substantial melt and because of the storms major weakening of the ice that is still there. Unless we get record braking cold this winter to not only add volume, but strengthen the ice that is there, I do not see the 'rebound' is being that effective at slowing the long term decline of the ice, because all it will take is one medium to bad summer (for ice), and you will still see record melt occurring.
BTW last year was to also be a year of limited melt based on cloud and temps.
Posted by: LRC | August 19, 2013 at 22:56
Jim D suggests (if I may paraphrase) that maybe the variability giving rise to the cool summer in the high Arctic is not all 'natural.'
Well, maybe. I don't think we're going to know that for sure anytime soon.
But that thought does go along with the idea that we're getting extreme heatwaves somewhere just about every year now--but we can't predict where. (Can't remember where I saw that, even though it was just today, I think!)
Posted by: Kevin McKinney | August 19, 2013 at 22:56
@LRC,
You wrote:
"The amazing thing to me as that despite having weather that should have meant minimal melt in the Arctic, we still have substantial melt and because of the storms major weakening of the ice that is still there."
I don't follow this; When we had PAC-1, melting slowed down immediately. In July we had a period with weather being quite condusive to melting, and so the ice did melt.
Then we had PAC-3 (PAC-2 not having much impact either way), and again we saw e.g. on CT that SIA held steady for a week and then followed average rate of melting.
You can look at PIOMAS average thickness (http://psc.apl.washington.edu/wordpress/wp-content/uploads/schweiger/ice_volume/Bpiomas_plot_daily_heff.2sst.png) and see that from trailing 2010, '11, and '12 by the beginning of this year, we now have both a larger sea ice area and increased average thickness.
'Recovery' is a big word, but we have certainly had very favorable weather, and the ice has responded favorably during those periods.
Where did you see weather being favorable to the ice, but substantial melt taking place?
Posted by: John Christensen | August 19, 2013 at 23:25
Wasn't there something about abnormally low ice leading to a re-bound, and vice versa?
I seem to remember something about there being a negative correlation between the ice area in one year and that in the next.
I thought I saw it either on the blog or the forum, with speculation about physical reasons for the correlation.
Anyway, maybe that's what's happening this year.
For whatever reason, it seems we've got some time.
I hope adoption of renewables means that we take advantage of it.
Posted by: James Lovejoy | August 20, 2013 at 01:00
John Christensen said
"...see that from trailing 2010, '11, and '12 by the beginning of this year, we now have both a larger sea ice area and increased average thickness..."
I agree we have both increased area and extent. I'm going to challenge the assumption the ice on average is thicker. I'm not so sure that is true, or will be true at the end of the season. I'm seeing some sites like Topaz suggesting the ice over most of the region is now well under 2M thick, and that most of the thicker formerly fast ice has dropped dramatically in thickness, or been shuttled out the Fram.
What tools do we have to better establish the actual volume?
Posted by: jdallen_wa | August 20, 2013 at 05:56
I thought that the question around sea ice thickness was interesting. Probably all of this has been gone over before, but...
As a sort of a rough proxy, I divided the PIOMASS volume data by the CT area data. Tonnes of caveats, since PIOMASS is modeled, etc. But basically, at the annual area minimum, average thickness had been in the 2 - 2.5 m range from 2007 - 2009, then dropped to 1.5m in 2010, and remained there in 2011 and 2012. Furthermore, the 2013 calculated thickness is right on track with the 2010 to 2012 thickness to the end of July. Seems likely to be a function of first year vs multi-year ice.
Interesting though that the differences in area at the annual minimum in the 2010 to 2012 period are so much more significant than the differences in thickness, and in fact the two don't necessarily track each other - either a model artifact, or a function of a limited sample, or an interesting clue to a different regime in ice process, as versus preceding periods where thickness and area were both dropping.
Posted by: Robert S | August 20, 2013 at 07:42
..
The temperature north of 80 ° width increases again slightly.
http://ocean.dmi.dk/arctic/meant80n.uk.php
And comes from the Barents warm air and warm water the next week. It can happen a lot. In 2011, it was the last 12 days in August, much ice loss.
http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2011081818_2011081900_035_arcticictn.001.gif
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http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2011083118_2011090100_035_arcticictn.001.gif
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I am of the opinion that the final melt begins
with the first new ice. Paradox? No!
When the first ice formation sets in, more water will sink into the depths again. New water must flow in faster. It will come from the Barents Sea and the Chukchi Sea.
Posted by: Gerhard Trausner | August 20, 2013 at 10:27
The Arctic is getting warmer again.
http://ocean.dmi.dk/arctic/meant80n.uk.php
2011 in the last 12 days in August,
melted a lot of ice.
http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2011081818_2011081900_035_arcticictn.001.gif
----
http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn/nowcast/ictn2011083118_2011090100_035_arcticictn.001.gif
----
In the next days the warm wind comes from the Barents sea.
The last big melt of the year begins with the first new ice formation.
Pradox? No.
If begin to form ice, lots of water falls into the deep. The influx is stronger.
The means, that more water from the Barent and Chukchi sea must flow back.
Posted by: Gerhard Trausner | August 20, 2013 at 11:27
Anyboby knows what's happening to IJIS/JAXA?
They haven't updated since the 16th...
@ toby
Like yourself, I reckoned on a 4.5m m^2 this year - it may still squeak down to that, but I am reckoning on a 4th or 5th lowest ever.
I note that while SIE (Jaxa) is currently tied up with 2008 & 2010 (at least it was on the 16th !), SIA (CT) is well below these two years (3.66 & 3.91 respectively); in fact it is currently below 2009(3.94). You have to go back to 2006 (4.38) to find a higher SIA at the same date ( Day 6274).
Even if 2013 ends up in 6th place for minimum SIE ( around 4.9-5.0, behind 2012, 2007,2011, 2008 & 2010), it is likely to end up in 7th place for minimum SIA (around 3.5)
Posted by: Phil263 | August 20, 2013 at 13:36
Despite the cold weather Petermann is still on the move, a small fringe calving is now seen:
https://forum.arctic-sea-ice.net/index.php/topic,53.msg13005.html#msg13005
Posted by: Espen Olsen | August 20, 2013 at 14:30
Hi Neven,
my first comment, so time to take my hat off to you for all you've been doing over the last couple of years. This blog has become a never-ending source of excellent information and worthwhile discussions. Very well done.
Of course, it got most exciting last year when everything up north went crazy. This year (for the time since I am following what's happening in the Arctic), the weather seems to be determined to stop not only the melt, but also the volume loss. Something I actually suspected to happen sooner or later, as most of the concerning literature keeps suggesting that part of the enhanced Arctic amplification we've seen in recent years might be due to favourable NAO/AO conditions (which could well switch back to less favourable conditions for melting). While I tend not to overestimate these findings, I wouldn't be surprised at all to see a couple of years in which the weather is doing strange things (though in the opposite, i.e. cooling, direction). In turn, we probably wouldn't see these extreme cold Eurasion winter anomalies anymore, leading to accelerated global warming as the net effect is clearly positive. Sure, nowadays open Arctic water (that used to be covered with ice) will keep affecting the circulation, but to what extent remains a mystery.
What I'm saying is, this years cold Arctic weather could be a fluke (which is my current thinking), or, potentially, a more fundamental shift in what the preferred NH-circulation pattern for the next 5-10 years might look like.
But I'll be blunt, there is another reason for my first posting here, and I admit I feel more than a bit ashamed to be such selfish and invasive likewise. I could offer some more detailed 2m temperature anomaly maps, similar to the one you're currently using. Since I wanted to have something more sophisticated for myself (after having lost the maps which are now commercially available at weatherbell.com), I started to put my own forecast maps (based on NCEP/CFSR and GFS) together, and subsequently operationally online. Being publicly available, some might find it interesting: [www.karstenhaustein.com/climate]
Use it or ignore it, I'm perfectly fine either way ;-). Having been so intrusive, I hope I can make up for it in that I keep contributing here in the future ...
Posted by: Khaustein | August 20, 2013 at 15:31
LRC: "As far as the dust cloud is concerned. May influence local, but the cloud was very minor compared to most volcanoes that erupt every year and do not have much impact."
Thanks, I was trying to get a gauge on the amount of dust from that event, which apparently is not that much.
LRC: "Unless we get record braking cold this winter to not only add volume, but strengthen the ice that is there, I do not see the 'rebound' is being that effective at slowing the long term decline of the ice..."
Agreed. Trend is definitely down and nothing to suggest a change in direction long term. 2012 was such a huge new low record it was not surprising to me it was followed by a rebound year, just surprised by how much (unless of course there is some major late melt which Gerhard is suggesting is possible).
Posted by: Hans Gunnstaddar | August 20, 2013 at 16:19
@jdallen,
There are a few websites dealing with thickness, but I do not know who reliable they are during the melting season due to the cloud cover. Therefore, I typically look at PIOMAS, which seems reasonably reliable for volume data, allthough this is just a crude average thickness calculation (http://psc.apl.washington.edu/wordpress/research/projects/arctic-sea-ice-volume-anomaly/).
Posted by: John Christensen | August 20, 2013 at 18:37
Khaustein - you should write a post in the Forum describing your forecast maps. I'd suggest the Short to Medium Term Arctic Sea Ice Conditions Discussion topic. We always appreciate new user-generated tools.
Posted by: Kevin O'Neill | August 20, 2013 at 19:55
--
Sorry, my last post is double.
I thought I had made a mistake when first creating.
Posted by: Gerhard Trausner | August 20, 2013 at 19:59
Gerhard, your comments ended up in the spam bucket (working better now, but still some comments will get caught). I released them without looking. Sorry about the inconvenience.
Posted by: Neven | August 20, 2013 at 21:48
@John Christensen - I'm a frequent visitor to that site. In fact, I'm just a couple of miles from UW.
Unfortunately, the margin of error is rather high +\- 750 km2 from reading I did there, larger for some measurements. At current conditions, that's almost a 40% swing, based on the 2012 estimate (3372km3, by way of Jim Petit). QED, if I understand, I don't yet think we can safely conclude volume is recovering.
Posted by: jdallen_wa | August 20, 2013 at 22:16
I wish we could edit ...+\-750KM*3*
Posted by: jdallen_wa | August 20, 2013 at 22:35
Posted by: John Christensen | August 19, 2013 at 23:25
I don't follow this; When we had PAC-1, melting slowed down immediately. In July we had a period with weather being quite condusive to melting, and so the ice did melt.
Then we had PAC-3 (PAC-2 not having much impact either way), and again we saw e.g. on CT that SIA held steady for a week and then followed average rate of melting.
PAC-1 I would argue broke up and spread thinner the ice thereby making the appearance of slow to stopped melt. Same for the others. We have not seen any winds yet that have actually compacted the ice.
As far as volume is concerned. I really believe even the thick MYI is nothing but slush. Get the right conditions and that would all be broken up very quickly. Remember, the end of last year there was almost no MYI left. Was the winter and summer so great for ice production that the MYI we have this year is as hard and compact as the 9 year ice of 30 years ago? I think not.
The mass we calculate today is based on volume and thickness with the presumption the ice 20 ft. thick is as compressed and compact as those of 30 yrs ago. Evidence of wave action reaching in 100s of miles into MYI and smashing it to pieces shows MYI is NOT MYI of yesterday and therefore I am not excited about MYI whatsoever. I am treating it as thick FYI.Not even compressed FYI.
Posted by: LRC | August 20, 2013 at 22:45
Guys , its been so cloudy most seem to not realize how loose the ice is , particularly in the Russian sector of the Pole. But I believe that this capture:
http://eh2r.blogspot.ca/
from NASA August 20, 2013 is a view very close to or at the North Pole. PLease confirm and take a look .....
Posted by: wayne | August 20, 2013 at 22:54
After two weeks of lurking on a laptop in France, I have some observations that I’d like to contribute.
Back at my CAD screen in the Netherlands, I’ve used this day 232/231 MODIS compilation (enhanced to make structure stand out) to discern the ‘mesh pack’.
This is what I found:
The fat red line marks the boundary. The choices I made are arbitrary, sure. But I made them with the same mindset as I did on 29 June.
Then, I found 1,5 Mkm2. Now, 20 August, the area has shrunk to 1,1 Mkm2.
For several reasons, I hold the structural unity of the pack to be a decisive attribute in the fate of the Arctic sea ice.
I have no comparable MODIS tiles to give a studied opinion on the situation then. But I have a strong sense that the area covered by the high concentration ice then, 3,7 Mkm2, corresponds with the visible aspect of what I call ‘mesh-pack’.
As a function of structure, the state of ASI is still getting worse.
I’ll elaborate on my thoughts on the Forum…
PS Wayne, I did fiddle a bit on the map above in a rad.35 km circle around the Pole. IMHO it is essentially "ice-free"
Posted by: Werther | August 21, 2013 at 00:06
Oh bl... the comparability I was hinting at then...then was 2007. I should post with more care...
Posted by: Werther | August 21, 2013 at 00:08
Very nice maps you have there, Karsten!
Do you think you could make a temp anomaly map for the Arctic, with the North Pole in the middle (stereograpic, they call it?). A bit like this DMI map, but then anomaly.
Posted by: Neven | August 21, 2013 at 00:37
Thanks for the confirmation, and very well done work Werther. If we can pinpoint this NASA photo with an overlay dot, would be impressive.
Makes a nice article for Neven's site.
Posted by: wayne | August 21, 2013 at 00:44
@Werther,
Yes, great work, and I agree that this is interesting as this 'mesh pack' is the ever-shrinking remains of Arctic MYI (not getting into the structural integrity question, which I agree with other commenters has already deteriorated significantly).
Question: Would you think it is possible to trace the 'mesh pack' all year, or would it be easier just to trace the 'mesh pack' left by mid-September and then retrace by early June to see what was gained in winter and then what is lost during the melting season?
While most significant ice-loss years, like 2007 and 2012, are showing excessive summer melting, it seems like ice-loss in some other years, e.g. 1981 and 1990, were triggered by lack of volume gain during winter related to relatively warm Arctic winters (http://ocean.dmi.dk/arctic/meant80n.uk.php).
It would therefore be interesting to see how the 'mesh pack' has developed from '07 until now. It probably would not show the increased variability that we see on SIA and SIE for summer and winter, but a more continuous drop like the PIOMAS volume charts..
Posted by: John Christensen | August 21, 2013 at 02:31
How badly broken up is the MYI if you can detect waves passing through it? We know from what took place when the Larsen B shelf disintegrated that any time floating ice breaks it rolls until the mass is stable buoyantly. What I mean is, if the ice is 4 meters thick and breaks off in a 3 meter wide segment it will roll over sideways so that it is then 4 meters wide and 3 meters high. The thinnest dimension naturally gets arranged as the vertical dimension. The same thing is true of icebergs far out to sea, as they melt they will roll so that the thinnest dimension is always vertical.
If 20 meter thick very old sea ice is being broken into smaller than 20 meter pieces the same thing will take place, which will give the appearance of greater area and extent even if the volume is static. The reality is however that the less than 20 meter pieces rolling over will end up as 20 meter wide pieces of less than 20 meter thickness so they will melt easier.
Posted by: Allen W. McDonnell | August 21, 2013 at 06:37
Wayne, I did start an overlay yesterday in the 35km radius around the Pole. Tiles r04c04/r03c04 came in fine and clear. But tomorrow I felt a bit disappointed as I saw the definitive versions of the adjacent tiles on the CAA side. Maybe Jim Hunt FI could pick out a clearer image?
John, I picked up this structural “mesh-pack” archetype when I was busy on my North-Greenland CAD-count June ‘11. I’ve been following it’s properties ever since, losing trace in winters’ darkness. Last winter, also triggered by the work of A-Team, I more or less figured out how to interpret ASCAT pics to follow my archetype. I’ll try to find some representations dating back to at least ’07 to back-up my suggestions.
Allen, I doubt if a comparison with the Larsen Shelves in Antarctica is relevant. I see what you mean, the process was also clear on the Wilkins Shelve two years ago. But the process of fading “mesh-pack” MYI in the Arctic looks different.
In it’s original form, the pack is/was meshed into trapezium shaped areas, averaging about 1000 km2, by stress leads. They start to widen as the pack gets more mobile, prone to, FI, tides. The ridging on their sides gets weaker, starts filling the leads with debris. Mechanical forces fracturize this further and eventually starts decomposing the large trapezia into smaller floes, following the secondary cracks that were already present.
What happens is not just melting but structural weakening. I refer to Wayne’s suggestion that temps lower than -11 dC are necessary to “build ice”. As long as the temps are above, this structural weakening continues.
That’s why I’m not focusing on “small” temp anomalies as the main indicator that a melt season is conducive or not. This year we have relatively large extent, large area, PIOMAS even numbers out large volume.
But on the quality side, which is to my great sorrow a “weak” indicator, 2013 continues the range of loss…
Posted by: Werther | August 21, 2013 at 08:11
@Kevin
These are just rough calculations, but they give the basic idea.
The GFS analysis in summer regularly shows at least some areas of precipitable water areas over the Arctic Ocean in the 20s of mm, and sometimes even in the 30s, although the average is lower.
The heat of vaporization of water is 4460 J/g and the heat of fusion of ice = 334 J/g. 2 g/cm^2 of water vapor gives us a water vapor content difference of roughly
2 x 2260 = 4460 J/cm^2 = 14 cm ice
There is a roughly a maximum 20C difference in temperature on the 850 mbar countour, and the Cp of air is roughly 1 J/K/g Assuming that this continues throughout half the 1000 g/cm^2 of atmosphere gives a dry heat content of
1 x 500 x 20 = 10000 = 30 cm ice
This is probably overestimated by 1/3 or so because the temperature differential goes down with height.
So the the heat content transfer as water vapor during the summer is a little smaller than the dry air heat content transfer, but the water vapor accounts for a little more of the variability.
Near the surface of the ice, the saturated heat capacity is about 1/3 due to water vapor, so the condensation flux is never more than about 1/2 of the dry air heat flux. If it's gaining heat from an air mass which has more water vapor than this, the additional water vapor gets converted to heat as fog condensation.
Posted by: Blaine | August 21, 2013 at 08:22
@Wayne
Yep, that's the pole. The actual pole in your image is towards the bottom and near the center horizontally, and is clearly marked by converging splicing artifacts. It's the point of that exactly triangular cloud bank pointing towards the upper left.
Posted by: Blaine | August 21, 2013 at 08:33
Wayne & Werther - DanP is really your man for extracting signal from MODIS noise. I just take snapshots from NASA Worldview through the day, as the swaths overwrite each other. The final Terra version of the pole yesterday that Wayne shows covered up some holes. Flip to Aqua to see a bit more detail on the 0 degrees side. Here's what I came up with:
As you can see, it is possible to add lat/long lines to Worldview. If the link above doesn't do it automatically, just check the appropriate box near the bottom of the "Add layers" list on the left.
Yet another Typepad pain BTW. Couldn't sign in using Facebook, Wordpress or OpenID :(
Posted by: Jim Hunt | August 21, 2013 at 11:40
Whoops. Forgot about another couple of Typepad pains. The full image can be seen at:
http://econnexus.org/wp-content/uploads/2013/08/2013-08-20_PolarWorldview.jpg
Posted by: Jim Hunt | August 21, 2013 at 11:45
P.P.S - See also http://forum.arctic-sea-ice.net/index.php/topic,167.msg13088.html#msg13088 for some much better images.
Posted by: Jim Hunt | August 21, 2013 at 11:52
Thanks, Jim,
I hope Dan can come up with some hot pic! For now, some 4-15 km2 floes are circlin' the pole with a labyrinth of polynia's of a comparable size and a lot of debris. The virtual Pole-axis may be on a small floe sized 6 hectares; pixel-size. Enough to get an impression of solidity when you'd actually stand on it... OTOH, it changes with the wind, I don't think this has been a common situation for a long, long time.
Posted by: Werther | August 21, 2013 at 11:57
I think dismissing the effect of the meteor is suspect. while it is a smaller amount of dust it is originating in the very top of the atmosphere rather than from the surface and the meteor path was at high latitude whereas volcanoes are generally at much lower latitudes so this dust is far more likely to be directly over the Arctic.it is the most significant, isolated and obvious short term local event in the northern hemisphere that would increase northern hemisphere cloud cover is it not? this year is a freak and I predict that next season will revert to the downward trend. this season is an illusion anyway extent does not tell the whole story does it. if the current ice were wind blown so that all those visible spaces that are so abnormal vanished then the extent would be far closer to what we would have expected. first time I have seen a big hole at the north pole on MODIS.
Posted by: philiponfire | August 21, 2013 at 14:25
Volcanoes are scattered all over the surface of the Earth, not just in the low latitudes. They often but not always follow plate boundary lines and they exist as a result scattered over Antarctica, New Zealand, South America, Alaska, Siberia.
Some are isolated peaks deep within the continents themselves like the San Fransisco Volcanoes of Arizona or Yellowstone Caldera in Wyoming. Mount Forel in Siberia is the largest known Shield Volcano on Earth, it is like the set of four giant shield volcanoes on Mars, Olympus Mons and the three Tharsis Montes.
Posted by: Allen W. McDonnell | August 21, 2013 at 17:12
@Philiponfire -
I was waiting for this. Of the volcanoes I mentioned, all of them are at approximately the same latitude as where the meteor entered the atmosphere - 55N - or further north.
With both the volcanoes and the meteorite, the greater fraction of material fell to the ground in the immediate vicinity of the event. And while that small fraction from the meteorite entered at altitude - greater than 20KM - similar fractions of fine dust from volcanic eruptions does make it to nearly that altitude, in quantities which dwarf the amount left by the meteorite.
It also pales by comparison to terrestrial dust storms, which while for the most part stay below 2KM, loft not thousands of tons, but MILLIONS of tons of dust into the atmosphere. Even a minute fraction from one entering the stratosphere would easily surpass that contributed by Chelyabinsk.
So, my point is, that the scale for the meteorite is off, as well as the location - latitude - for it to have contributed significantly to the behavior of the arctic this season.
Posted by: jdallen_wa | August 21, 2013 at 17:33
Edit - just realized I talked about the volcanoes on a different thread - but if you check eruptive histories with the global vulcanism program, you will see this year that nearly a dozen eruptions of VEI 1 or higher have taken place in the Kuriles, Kamchatka and the Aleutians, all of which are at or near 55N.
http://www.volcano.si.edu/region.cfm?rn=10
http://www.volcano.si.edu/region.cfm?rn=11
Posted by: jdallen_wa | August 21, 2013 at 17:41
Keeping the MODIS data downloads up-to-date (it's 18 GB a day for the whole Arctic!) is always the challenge but hopefully I'll toss out a few more images/movies. And as a teaser, here's a new product I'm making that's almost ready for primetime:
This is a 2.5-day mosaic I constructed directly from the .hdf swaths by means of dividing into 105-pixel squares, and then choosing the observation swath for each square with the clearest view, as determined by a whole host of criteria such as (band1)/(band6 + band7) ratio for apparently icy pixels, min(band1 + band3) for water, altitude of sun, etc. etc. Full resolution is 500m/pixel.
It is quite blocky for cloudy periods but it already looks much cleaner at a pixel level than my 8-day composites based on NASA's processed tiles, which smear out features that are changing in time. In clear periods and during higher-sun times of year it may be useful even as a daily composite. Right now I'm pulling down a few more days of data to see how good it looks with a few more days composited together.
Posted by: Dan P. | August 21, 2013 at 17:41
very cool Dan P.
If I were you I would contact the folks at Google and get in on the earth engine beta.
Posted by: Stevemosher.wordpress.com | August 21, 2013 at 18:07
Yes, indeed DanP. Also contact earthdata.nasa since you have improved on their offering in a way that will interest many end users.
For the hdf and netCDF files, I'll remind people of free desktop software Panoply. However 18 GB of daily download is not going to prove feasible for most people. And when downloaded, you cannot afford to experiment on very large files so get your pipeline down on smaller test files.
Even the last few weeks, which have seen very little coherent ice motion, still introduce too much jitter into an eight day product relative to 0.5 km pixel resolution, so three cheers for 2.5 days.
While floe motion vectors are supposedly provided daily and Gimp etc offer very nuanced motion blur correction, I'm sceptical that these could really improve time-composited ice imagery, though 2.5 days is a lot more favorable for that.
I looked at band 31 (11 micron infrared, 1 km resolution) on earthdata.nasa to see if it offered anything to complement the shorter wavelengths you have been using but it has mostly to do with cloud temperature.
Oblique cloud shadows on ice are removable -- unlike thick clouds directly over ice. Cloud height could also be obtained from the sun angle at swath time.
In fact, an overall daily cloud/fog/vapor product from all the wavelengths out there would be very useful for interpreting conditions affecting the ice.
Posted by: A-Team | August 21, 2013 at 19:14
There may be as many as 3 reasons these composites have better local detail than the other 8-day product I've been spitting out:
1. The previous 8-day averages are from tiles that had already been projected to a sinusoidal grid; though this is mathematically invertible, there are inevitable resolution losses in the areas with largest distortion, i.e. near the pole.
2. NASA's compositing algorithm *may* be averaging multiple swaths, which will inevitably smear movement detail. The documentation has left me somewhat confused on this point. In any case, my method is displaying actual unaveraged swath crops, which are merely chosen to be the clearest of the available ones.
3. NASA's composite is pixel-by-pixel, which means that neighboring pixels can be chosen heterogeneously across the time interval, which also effectively smears any motion.
#2 and #3 don't matter for most of the planet, and in fact will generally enhance detail on vegetated areas than don't change quickly, by averaging down noise due to varying light conditions, etc. But they make a hash of the moving Arctic ice floe details.
Posted by: Dan P. | August 21, 2013 at 21:19
If you go to the interactive graphing page on Cryosphere Today http://arctic.atmos.uiuc.edu/cryosphere/arctic.sea.ice.interactive.html and turn off all the years except for 2009 and 2013 you will see that for the last 17 days the two lines are very nearly parallel. If this holds for the rest of the season we will end up below 3,500,000 km^2 Sea Ice Area, which is nothing to cheer about. Sure it would leave us a million km^2 higher than 2012, but most people agree 2012 was an outlier year, a much steeper drop than projected. Perfect beginning of the season coupled with a late season storm that scattered fractured thin ice into warm surface waters is pretty much the definition of a perfect melt year. Until 2006 every year ended the melt season with more than 4,000,000 km^2 of residual ice, since then the best year was 2009 with 3,424,600
Posted by: Allen W. McDonnell | August 21, 2013 at 22:32
Kevin: Thanks! I did attach a FAQ section. Hope that helps. I might write a post there once the Arctic maps are available.
Neven: Thank you too! Sure, I did actually generated maps for the Arctic (cirumpolar; stereographic proj.) during the development phase. Space constraints at my poorly designed main page led me to discard them. Plus, there are already some rather sophisticated anomaly maps available elsewhere (which you may or may not know), though not for surface temperature: www.meteociel.fr
Anyways, I decided to spend some time jazzing up the main page such that I can also include Antarctica and the US. Might take some days or weeks ...
Posted by: Khaustein | August 22, 2013 at 01:11
Abrupt disconnect over at Navy Hycom, as first noticed over on the forum. They've radically increased the thickness and altered distribution of first year ice.
Some models need to 'tie in' periodically to observational data to reset themselves to reality. Fine. But where would that come from with ice thickness in mid-August?
Apart from correct peripheral ice boundary, they're still wildly inconsistent with high resolution satellite display of unambiguous open water [Modis and 89Ghz], 2 m being worse than before. If this is an revised algorithm, how was it judged ready for release?
I could find no explanation offered -- surely they have an unpaid intern not too busy to write up a few lines. I'm not sure how far back they are recomputing but 01 Aug 13 at least. Also it appears they have overwritten previous 30 day runs. What then becomes of year to year comparison?
Posted by: A-Team | August 22, 2013 at 01:28
In the absence of regular SIE update from IJIS/JAXA, we have to rely on visuals to evaluate the progression of the melt.
Comparing the uniBremen visualts between 15 August and 20 August ,one notes the following:
1. Overall, the melt does not seem to have progressed much, particularly near Severnaya Zemlya where the Northern Route is still blocked and the ice seems to be holding out
2. There is a clear refreeze of the central pack North of 80N, particularly North of Svalbard
3. I notice some ice in the middle of Hudson Bay that wasn't there last week, probably drift ice rather than re-freeze.
4. There is a noticeable melt in the NW passage but it seems that the passage will remain closed at its Western end ( between Banks and QE Islands)
Posted by: Phil263 | August 22, 2013 at 02:18
DMI satellite SST analysis also seems to indicate water temperatures lowering in Beaufort, ESS, and Laptev. Hudson SST is too high to provide any freeze yet:
http://ocean.dmi.dk/satellite/index.uk.php
Posted by: John Christensen | August 22, 2013 at 03:21
I find uniBremen images quite erratic with day-to-day changes that cannot be real, and the satellite images of open water near the Pole do not match well the high ice concentration shown on uniBremen.
CT is blurry, but at the same time more stable with regard to the concentration mapping.
Posted by: John Christensen | August 22, 2013 at 03:57
"The ACNFS has been using atmospheric forcing from the Navy Operational Global Atmospheric Prediction System (NOGAPS). However, NOGAPS is scheduled to be decommissioned on 31 Aug 2013. It has been replaced by the NAVy Global Environmental Model (NAVGEM). A data assimilative ACNFS hindcast using NAVGEM forcing has been initialized from NOGAPS-forced ACNFS in June 2012 and run up to date. Within the next week,the Naval Oceanographic Office will switch from ACNFS with NOGAPS to ACNFS with NAVGEM and the former will no longer be running in real time."
http://www7320.nrlssc.navy.mil/hycomARC_nogaps/skill.html
Posted by: Fairfax Climate Watch | August 22, 2013 at 07:55
A-Team - To summarise, the accompanying verbiage also states that "The Naval Oceanographic Office switched from ACNFS with NOGAPS to ACNFS with NAVGEM on August 20, 2013. The NOGAPS forced ACNFS is no longer running in real time."
The "old" runs haven't been overwritten. They can still be accessed back to 2010 and up to August 19th via http://www7320.nrlssc.navy.mil/hycomARC_nogaps/arctic.html
The "new" runs are available in the "old" location at http://www7320.nrlssc.navy.mil/hycomARC/arctic.html
The Navy mention assimilation of ice concentration data amongst other things, but not of thickness.
I've previously been informed that "the CICE model is much more sensitive to forcing data than to internal model parameters", and this seems to prove that point. In all the circumstances year to year comparisons going forwards would seem to be highly problematic, unless a hefty dose of reality is somehow assimilated in the very near future!
Posted by: Jim Hunt | August 22, 2013 at 10:39
There is no ice in the Hudson Bay.
There is no refreeze North of Svalbard.
Posted by: Chris Biscan | August 22, 2013 at 11:47
IJIS/JAXA has not updated since Aug 16. Masie hasn't updated since Day 229 (Aug 17?). What is the problem? The IJIS site is showing daily maps until Aug 21,so I am surprised they do not have the data...
Posted by: Phil263 | August 22, 2013 at 12:33
Currently at about 80 degrees, north(ish) of the Bering Strait, Séb Roubinet reports this morning (in French) that "The ice breaks up and melts before our eyes".
Meanwhile, and whatever ACNFS or Bremen might suggest, Terra is still working fine and through a thin veil of cloud reveals this north(ish) of Svalbard:
Posted by: Jim Hunt | August 22, 2013 at 12:59
@Jim
Actually, the model evolution since the the reset is not to my eye obviously different from the old model. The big difference is the initialization. Compare the old and new thicknesses. The new initialization just isn't remotely like anything HYCOM has ever turned out as a model result in summer. Maybe it's been spun up at an extreme low resolution? Neither do the new and old fields exactly match at any time, so I really have no idea how they came up with the new initialization.
Year-to-year comparison will be broken for the next year or so, and optimally they should reanalyze the whole data set with the new forcings. It's mostly turned out for operational use, so they don't prioritize year-to-year comparability.
It is mostly a forcing-driven model, but it still depends a lot on the internal parameters and approximations. They don't seem to have changed those, though.
Posted by: Blaine | August 22, 2013 at 13:44
Jim, agreed. Today's early glimpse into MODIS looks as terrible as ever. But for the awkward fast ice hitched to Severnaya Zemyla, he Atlantic side is getting shaved back very dramatically this year. That is something to be said about one of the more atrocious aspects of this year, in spite of higher overall extents than recent years.
Posted by: GreenOctopus | August 22, 2013 at 15:38
Hycom ice color has always been jpg'ed and never corresponded to the colors in the key (which was added back to the image afterwards).
The third mistake was not doing the key initially as overtint of a uniform grayscale. Thus it is all but impossible to fix the palette without drilling down into their file system to find the raw numeric array, assuming they archived that.
Grayscale is the universal scientific standard for numeric manipulation of images displaying 1D data (concentration, thickness etc are maps: I^2 -> +R^1).
As things stand, we have no real mechanism for quantitative comparison of new and old. For what it was worth, I subtracted the two 01 Aug 13 images Blaine supplied, adding neutral gray 128 to keep everything within bounds [0 255] while sticking to native resolution (1/12º ~ 10km/pixel).
(Their documentation speaks of 3.5 km resolution at the pole, applicable perhaps to the one map inexplicably offered in Mollweide; the rest are stereographic. There, simply count pixels from pole to the Siberian shore grazed by 70ºN to determine resolution.)
I've always wondered where the heck they get their underlying imagery and why they don't check in occasionally with something better to ground the product model in observation.
Ice thickness seems to be calibrated off a sparse radar altimeter: "NCODA assimilates available satellite altimeter observations (along track obtained via the NAVOCEANO Altimeter Data Fusion Center), satellite ice concentration..." The satellite instrument and concentration algorithm are not specified but I suspect none of the ones we use.
This is a highly sophisticated model outputting a product that never stood up to the slightest scrutiny -- seemingly the paradigm for climate science modelling (no result, publish anyway):
"Hydrostatic approximation, hybrid pressure coordinate, fourth-order LaPlacian for vorticity, divergence, virtual potential temperature, specific humidity, surface pressure, ground temperature, ground wetness, cloud fraction, horizontal spectral differencing, second-order finite difference in the vertical, central time differencing with Robert semi- implicit corrections,42 sigma levels with 6 sigma below 850 mb,00Z, 06Z, 12Z and 18Z ops run, Machenhauer initialization, NOGAPS 6-h or 12-h forecast, spectrally truncated and Lanczos filtered heights, convective precipitation (Emanuel), shallow cumulus mixing (Tiedtke) and large-scale convection, long-wave and short-wave radiation (Harshvardhan) computed every 2 hour, gravity wave drag, planetary boundary layer, sea surface temperature and ice coverage percentage from OCEAN MVOI."
Posted by: A-Team | August 22, 2013 at 16:30
8-day composite through yesterday (day 225-233), via the new method. Longer runs reveal occasional glitches in the selection routine where an unusual cloudy square has managed to beat a clear one in my selection criteria, so I'll do some more debugging of that. But it's already quite useable at the 100% zoom although pretty ugly due to brightness/color variation from the blockiness. Because the underlying data I'm using is surface reflectance (corrected for sun angle, etc.), if I were able to choose entirely clear scenes, there should be no color or brightness variation when crossing mosaic squares. In practice the correction algorithms are never perfect, and of course unremoved clouds will always be a distraction.
Channels 1+4+3, 12% scale:
Channels 7+2+1:
1+4+3, 33% crop:
1+4+3, 100% crop:
Posted by: Dan P. | August 22, 2013 at 16:58
Nice work Jim, now we know for sure the pole has open water roughly 50% of the time. And so is the huge zone of loose pack about 50%, given so the melt this year is likely as significant or more than any. We should come up with a reasonable area number not at all the same as officially presented.
Posted by: wayne | August 22, 2013 at 17:12
Wayne - having been staring at MODIS images around the pole for quite a while, it may be true that the pole is in water as little as 50% of the time right now. But that is because of a relatively small area of low concentration ice. Just away from the pole towards the western arctic there is obviously a solid 100% ice area.
The high latitudes and scales of these low concentration areas seem to be unprecedented but I'd like to get my composites working well enough to make fair comparisons year-to-year.
I agree that microwave seems to be being fooled at times by clouds right now, but I also take Peter Ellis's comments to heart that we're all pretty bad at judging concentrations by eye, as well as the fact that our eyes are all naturally drawn to the high contrast low concentration areas. So it's hard to make any quantitative statements about how much net area the microwave data might be mistakenly counting.
Posted by: Dan P. | August 22, 2013 at 17:58
Dan P. , Werther calculated 1.1 million Km2 solid pack, so the number for ice area is somewhere between 3.9 and 1.1 million Km2,
I'd say if we assume of the 2.8 million left there is 40% open water the theoretical compacted pack would be 2.2-2.5 million Km2. So instead of nature pressing the ice together as with previous years, we can do it in our minds or computers.
Posted by: wayne | August 22, 2013 at 22:29
Evening all,
Wayne, all the CAD aided work I’ve been doing, first on CT concentration maps since 2005, later on the invaluable MODIS tiles doesn’t trick me into believing my method is falsifiable/reproducible. Any CAD point I digitize is arbitrary. So, in more than one ways, Dan P. is right.
Even a thorough count over a defined area doesn’t mean the result is imperative. It is probable, not certain. The area is so large, the circumstances that different. That, IMHO, is in its essence the same problem for the professionals and modellers.
From what I’ve learned and calculated remains most of all a deep awe for nature’s power and beauty and a lot of gratitude for what Neven and my fellow followers have done to soothe the sense of being alone in the dark.
That said (I’m in a contemplative mood…), having thrown in the towel last Monday on my 3.28-4.0 SIE prognosis, I once more get this sense of nearing “malheur” going over and over the MODIS tiles the last days.
Even while accepting the blunt numbers, I still sense they’re not telling the whole story.
It is unbelievable how a year, with DMI showing an enormous 2m temperature deficit against the climo above 80dN, with NCEP/NCAR reporting a +1dC anomaly over Chukchi but plain normal climo temps over the CAB and even -2dC anomaly in front of McClure Strait, can produce a melt pattern and structural failure as we see. And it is still unfolding.
We can’t be sure from the past patterns for the future to be clear. The Arctic and the biosphere in general are chaotically spinning into “terra incognita”.
We have to prepare….
Posted by: Werther | August 22, 2013 at 23:31
IJIS/JAXA is back! and they've filled in the past week of missing data.
Latest extent is 5706719. This puts 2013 in 5th place, just 2k ahead of 2010, and 1.17M behind 2012. Last three days have averaged a respectable if unspectacular daily drop of 60k.
Posted by: Ned Ward | August 23, 2013 at 03:03
A-Team - Posey et. al. (2010) in "Validation of the 1/12° Arctic Cap Nowcast/Forecast System" covers in some detail how ice thickness data were used when validating the ACNFS model post 2007, but also states in the "Recommendation" section that:
"As thickness observations become available over time, further sensitivity studies and possibly assimilation of thickness data, will be incorporated into ACNFS."
I took that to mean the "satellite altimeter observations" weren't currently being used for some cunning CryoSat-2 style calculations.
They also state that:
"NCODA is initialized using the 24 hr ice concentration forecast from the prior day CICE output and then assimilates daily ice concentration data from SSM/I.... The ice analysis from NCODA is directly inserted along the MIZ. The NCODA ice analysis is then blended with the model’s previous day forecast in areas with concentration up to 40%. NCODA ice analysis values above 40% are not used in the assimilation."
It looks as though things like a potential "North Pole Hole" aren't really on the Navy's radar screen?
Posted by: Jim Hunt | August 23, 2013 at 14:14
HYCOM has been predicting North Pole holes that are larger than observed for years. Their most recent update before this actually mentioned reducing the size of the North Pole hole to better match reality as its main motivation, but still produces one which is too large. I think it's mostly due to having an ice strength that is too weak, so it can't resist being pulled apart strongly enough.
The text you're quoting is saying that basically the only correction of the modeled ice sheet to reality is correction of the edge location. Even if their analysis didn't run high, the North Pole hole still wouldn't be low enough concentration to be inserted as a correction. The model still produces the hole on its own so long as they don't arbitrarily replace their modeled weathered ice sheet with a big solid unweathered block of ice.
Compare the old data to the new data, and the difference is pretty obvious. The change is mostly the initialization and not the model, since the new thick, solid ice sheet they arbitrarily inserted is weathering quite quickly in the new model.
Posted by: Blaine | August 23, 2013 at 16:44
Blaine - It may look as though they arbitrarily (and recently?) inserted a 100% concentration ice sheet, but what the Navy say happened was that the NAVGEM forced model "has been initialized from NOGAPS-forced ACNFS in June 2012 and run up to date." If that's the case surely the modelled ice sheet should already be pretty well "weathered" by now?
Posted by: Jim Hunt | August 24, 2013 at 11:24
My son Ben Pelto is aboard the USCG Healy, after six days of clear sailing, reported hitting considerable sea ice yesterday. The sea ice also featured polar bears. 71 09.877N 134 55.579W. A video of the sea ice conditions encountered is at. Danny Blas
Posted by: Glacierchange.wordpress.com | August 24, 2013 at 12:35
...
It was a very interesting year 2013.
There were many factors that have helped to keep the ice.
But the fact remains that warms the Barents Sea from year to year.
I am of the opinion it will take a long time until the Arctic is ice-free. But they will one day free of ice.
A rise of sea water of 1m, would
bring a very different flow behavior of Pazific through the Aleutian Islands with it.
It would flow much more warm water into the Arctic.
Posted by: Gerhard Trausner | August 24, 2013 at 13:33
...
Maybe it's just coincidence.
But why HYCOM has changed its data when the NO-passage is open? Maybe they are committed to providing low to no data for navigation. This could have serious consequences.
But maybe they got
better and more accurate data from the ships.
Posted by: Gerhard Trausner | August 24, 2013 at 14:11
Wonder of wonders! DMI is actually, visibly (though only by a pixel or two) above the seasonal norm, for the first time in months.
Perhaps not coincidentally, the Canadian Archipelago looks like it's a tad cooler, while the North *Eastern* Passage seems to threaten to finally open up, with concentrations north of Severnaya Zemlya dropping (per CT.)
Posted by: Kevin McKinney | August 24, 2013 at 15:52
Thanks, Jim. I somehow avoided reading that it was 2012, and yes they're very close to the same for June 2012. In fact, they're not that far apart through June 2013, and then suddenly started diverging for some unknown reason. Tying different models together can be tricky.
Posted by: Blaine | August 24, 2013 at 20:30
Kevin
Wonder of wonders! DMI is actually, visibly (though only by a pixel or two) above the seasonal norm, for the first time in months.
Which DMI graph are you referring to?
The DMI 30% extent is still well below the margin of error.It's actually been dropping sharply in the last few weeks, bar an uptick yesterday. I am surprised that this drop doesn't show on the 15% extent JAXA gauge.
Posted by: Phil263 | August 25, 2013 at 00:35
http://barentsobserver.com/en/arctic/2013/08/first-container-ship-northern-sea-route-21-08
A most significant news regarding sea ice loss. Its the beginning of
new mass shipping route.
Posted by: wayne | August 25, 2013 at 00:52
Neven
Just a quick word of feedback.
I miss the discussion on the day to day SI evolution we used to have at this time of year on this blog. I know you have set up a separate forum, but it is not as user friendly[for me!] and I cannot log in...
It is also very confusing and time consuming to have to look in different places.
Posted by: Phil263 | August 25, 2013 at 12:30
Hi Phil,
I think the lack of day-to-day discussion is because this isn't a record year. It's more fun discussing Arctic sea ice loss when it's declining fast (if we forget for a moment about the potential consequences).
Last year the blog was much busier, which led to too much noise in the comment threads, and I felt forced to set up the ASIF. This year we get a bit of an opposite effect. Sorry about that.
Let me know if I can help you with registering on the ASIF. There are just two or three threads you need to follow if you want some of that day-to-day discussion.
Cheers,
Neven
Posted by: Neven | August 25, 2013 at 13:57
Hi Neven
No worries. I still enjoy reading the blog, in particular your excellent bi-weekly updates
Posted by: Phil263 | August 26, 2013 at 01:33
The DMI "temp anomaly north of 80" graph, found toward the bottom of Neven's SI graph page. I've been commenting about it sporadically through the summer, so assumed that most regulars would pick up on that context. One shouldn't assume, of course, and besides there are always first-timers and infrequent visitors, and I was leaving them a tad in the lurch by being lazy. Sorry for the inconvenience--and also for the slow response to your question.
Here's a link to the DMI page (I think this one will stay current):
http://ocean.dmi.dk/arctic/meant80n.uk.php
In any case, as you can see, that blip above normal didn't last long, and the high Arctic is once below seasonal norms. It's been quite amazing to me this summer how persistent that pattern has been. I'm sure that it makes some contribution to the comparatively slow melt--though a lot of the melt action is south of 80, to be sure.
Posted by: Kevin McKinney | August 26, 2013 at 19:27