When reading Chris Reynolds' second entry in the June Status series on his Dosbat blog, describing atmospheric patterns for the previous month in the 2004-2013 period, I remembered doing a similar thing last year in a blog post called Arctic atmosphere June-July 2012. In that post I divided the period from June 1st to July 15th up in three parts by using maps from the daily mean composites page from NOAA's Earth Science Research Laboratory.
This time I've combined maps showing sea level pressure patterns from 2007, 2010, 2011, 2012 and this year, divided into four periods spanning two weeks in May and June. I've chosen these years because they have been the biggest contenders for the records and have the most interesting features that help us understand the period after the shift in 2007. And of course, I already had the images that I used for last year's post.
Below the maps I have added Cryosphere Today sea ice area graphs (CT SIA) which will allow me to discuss certain correlations. The image is pretty big, so I hope it fits on everyone's screen when they want to have a closer look by clicking on it:
Before discussing the two months one by one - and bear with me, because it's going to get interesting -, here's a quick explanation on how to interpret these sea level pressure (SLP) maps:
The green, yellow and orange stand for high pressure, the blue and
purple for low pressure. In high-pressure areas the winds blow in a
clockwise fashion. In low-pressure areas it's the other way around: winds
blow in an anti-clockwise fashion. The direction and intensity of winds are usually represented by isobars (dividing lines between different
pressures), but in this case the different colours make
it clear enough.
The important thing to remember is that the ice follows the wind, with a bit of a lag and not as fast. With clockwise blowing winds the ice gets pushed together, under anti-clockwise blowing winds ice floes get dispersed (see image on the right). This has to do with the Coriolis effect caused by the Earth's rotation.
Another important difference between high-pressure and low-pressure areas is that highs make for clear skies, and thus lots of insolation during summer (or radiation out to space during the dark winter months). Lows cause cloudiness, and thus less sunshine reaches the ice pack during summer, making the air generally colder. During winter clouds can block outgoing radiation and thus increase air temperatures, though still below freezing. Depending on their position, highs and lows can pull in warm or cold air from the continents.
What makes area/extent decrease fast in general, is when highs dominate the American side and centre of the Arctic (the right half of the maps) and lows dominate the Siberian side of the Arctic (left half of the maps), because together they act like cogwheels - one turning clockwise, the other anti-clockwise - that push all the ice floes together and towards the Atlantic where they melt out. This phenomenon is known as the Arctic dipole anomaly.
Right, and now onto the analysis:
May
2011 (purple trend line) starts out low at the beginning of May and stays low because of lots of high pressure all around the Arctic. It is soon joined by 2010 (green trend line) that has a very quick start to the melting season due to a big high over the Chuckchi and Beaufort regions that weakens slightly after the first half of the month. You can clearly see the slight lag on the CT SIA map, because as I said it takes a while for the ice pack to respond when weather patterns stay put
for a while, especially early in the season.2007 and 2012 (blue and orange) aren't far from 2010 and 2011 at the end of May, also having enjoyed some high pressure during the first half of the month, turning into a Arctic Dipole (AD) during the second half of the month. The reason that 2012 drops slightly faster than 2007 most probably has to do with the fact that the ice in 2012 was a lot thinner on average after the 2010 and 2011 melting seasons.
2013 (red trend line) clearly stands out on the May CT SIA graph. It starts out alright, but the ice decrease soon stalls under the influence of the persistent cyclone that will dominate the Arctic for a couple of weeks, bringing in clouds and cold, but at the same time dispersing the floes in the interior of the ice pack.
June
2013 remains at a fair distance from the other years because of PAC-2013. A large low-pressure zone even envelops Greenland, which make for antithetical conditions compared to jaw-dropping 2012. This first half of the melting season is clearly very different from anything we've seen in recent years.
During all of June 2007 (orange) and 2011 (purple) keep dropping steadily due to some pretty stable conditions with highs continuing to dominate much of the area over the Arctic Ocean.
2010 has a bit of a lull during the first half of the month, but drops fast again when a relatively big high-pressure system takes over the Central Arctic. 2012 produces an even bigger high during the first half of the month, causing the trend line to plummet on the CT SIA graph.
And that brings us to the most interesting period of last year, a period that in some ways was more interesting to me than the period with the Great Arctic Cyclone that would cause havoc with a capital H a month later. In the second half of June the Arctic became dominated by a widespread low, and although the sea ice area decrease slowed down, it didn't stall completely like it did in previous years under similar circumstances (see last year's blog post on atmospheric conditions for further explanation).
We could be witnessing the same thing this year, even though 2013's start of the melting season doesn't come close to those of previous years, let alone 2012. We have to keep in mind though that this year did start out with a total volume that was as low as 2011 and 2012, the highest amount of first-year ice on record (due to last year's record minimum), and with PAC-2013 that has impacted the interior of the ice pack. We still haven't seen the full effects of that event.
There are basically three set-ups that determine the rate of decrease:
- Highs dominating the Arctic (negative Arctic Oscillation) -> fast decrease, especially if the highs are on the American side of the Arctic and stay put for a while, causing a lot of compaction.
- Lows dominating the Arctic (positive Arctic Osciallation) -> average decrease, faster when the pressure is very low. Lows on the Siberian side of the Arctic, combined into an Arctic Dipole with highs on the other side, cause the fastest decrease. 2007 was so special because the AD was persistent and relatively stable for almost all of the melting season. Were that to happen again in coming years, the Arctic could very well go ice-free before the end of the melting season.
- Neither fish nor flesh, neutral Arctic Oscillation, unstable weather systems that don't stay into place -> slow decrease.
What has changed compared to the past, is that the gaps between these three set-ups have become smaller, and this obviously has to do with the thinning of the Arctic sea ice pack. A less intense high can do as much damage as an exceptional high during the 80's and 90's. A large cyclone tears the ice pack apart, whereas the ice pack was much better able to withstand it in the past. Thinner ice is now dampening weather dominance.
And so we are entering that period of the new melting season, where area and extent keep decreasing steadily, even if the weather isn't all that conducive to transport, melting and compaction. With some favourable weather conditions in coming weeks 2013 might even join the top years, or possibly even have a shot at 2012's title (more on that in the next ASI update). It would be a remarkable feat after the unusually slow start to the melting season.
Given everything that has been said on this blog this melt season it seems amazing that Beaufort has a positive anomaly ATM. And given what has happened in past years that it's still hanging on in the Kara.
Posted by: Pete Williamson | July 04, 2013 at 02:44
Apologies, I was basing those comments on data off the Cryosphere Today website.
http://arctic.atmos.uiuc.edu/cryosphere/
(sea ice area)
Posted by: Pete Williamson | July 04, 2013 at 02:46
Neven,
For someone whose first language was not English, I continue to be amazed at your fluency, particularly when it comes to all things "scientific".
After 33 years of working with scientists and engineers in the Defense Industry, there were few native born Americans, in the fields of engineering or science, that had your grasp of the English language and the ability to communicate complex topics with ease.
After the ice melts, you might consider a second career teaching American engineers and scientist how to write coherently and fluently.
BTW, congratulations on the Forum surpassing 1,000,000 page views in less than five months. A remarkable achievement indeed!!
Posted by: OldLeatherneck | July 04, 2013 at 03:05
Another cogent analysis. Thanks, Neven!
Posted by: Kevin McKinney | July 04, 2013 at 05:31
The lack of open water in the Beaufort is really glaring compared to other years. I don't see how that is going to be overcome to help melt out the central arctic basin enough for a new record. It needs to be melted out first to get the sun to heat the water. We are weeks behind recent years there. The Atlantic side with the chopped up ice floes will get messy and retreat more than we have seen, though that is pretty far displaced from the bulk of the arctic basin on the Pacific side. So it will be a more cosmetic note to this season versus actually causing a new record.
Posted by: Henry1 | July 04, 2013 at 05:34
Does anyone have a theory as to why the beginning and end of the melt season have remained more or less the same since 1979 even though so much more ice is melting?
Posted by: Mdoliner43 | July 04, 2013 at 07:33
Thanks for the compliment, OLN. My ego jumps with joy. :-)
Posted by: Neven | July 04, 2013 at 07:47
I agree, especially about the Beaufort (PIOMAS has indicated that ice was thicker on the Siberian side this year). Who would've expected the melt there to proceed so slow, especially after the fragmentation event of February/March? Of course, the weather hasn't been cooperative for melting, but perhaps the fragmentation event somehow made the ice stronger as well. The Arctic is full of counter-intuitive stuff.
It definitely used to be like that, but perhaps this is now changing. Until recently the ice pack melted from the sides inwards. I believe that we'll see more and more melting in the interior of the ice pack. How much, of course, still depends on when the melting season ends. A large mesh of floes will close up very fast when the weather switches to winter mode sometime in September.
Wrt Beaufort, I'm expecting some very large and rapid changes in the coming two weeks. But more about that in this weekend's ASI update.
I'm not sure if they have remained the same (especially the beginning), but apparently the Arctic Ocean needs to warm up a lot more during the melting season to hold off the winter season.
Posted by: Neven | July 04, 2013 at 07:55
RE: Reasons for slow melt
Isn't it just temperatures? The fragmentation event occurred, but we've also seen below average temps in the Beaufort for the better part of 2 months and much of the arctic basin. I think we're underplaying the weather here. It just simply has not been as warm as recent years. Last I checked, it still takes warmer temperatures to melt ice.
RE: Central ice pack
I can see how that will accelerate melt to a point, but the problem is it is near the pole where the clock is ticking faster than anywhere else. The pack gets ugly and starts to melt, but before it can become too melted, it starts to slow down and then eventually refreeze. I bet we'll see unprecedented melt there, but it still doesn't reconcile the differences elsewhere, unless we think this melt season is going an extra month.
Posted by: Henry1 | July 04, 2013 at 08:13
One last thing.
RE: melting later
From this amateur's eyes, it appears the ocean loses heat faster once the sun sets when it is open water. This is said by many more refined experts on here and elsewhere. Same reason the melt is accelerated early in the season with open water. So is that a negative feedback? Open water sheds the heat much faster so the end of melt season really hasn't changed much. We'd need to see water temperatures get so warm that it cannot shed the heat fast enough to refreeze once the sun sets.
Posted by: Henry1 | July 04, 2013 at 08:17
Well, that's the whole point of this post. Because of atmospheric patterns (see big image and notice the difference with previous years) there was less insolation and thus also lower temps.
What we're going to learn this year is how important the start to the melting season actually is, in this new era of Arctic melting. It could be that these 1.5-2 months will cause the minimum to be above 2012, 2007/2011 and even 2010, especially if weather patterns remain in the 2) and 3) set-ups described at the end of the post.
But with a period of the 1) set-up, I believe the 2013 melting season could still end up somewhere between these years.
We're going to see and learn.
It is, just like increased snowfall on the Northern Hemisphere.
Posted by: Neven | July 04, 2013 at 08:26
Neven
This is the reason I think the start and end dates haven't changed much. There is a clear pattern of the colors shifting to the left, but not the end points
http://i137.photobucket.com/albums/q210/Sekerob/Climate/ArcticSIEDaysMillionStepMelts.png
Posted by: Mdoliner43 | July 04, 2013 at 08:27
Mdoliner43, I did a quick search:
Posted by: Neven | July 04, 2013 at 08:40
The NSIDC just posted results thru July 3rd. Don't look now, but the extent seems to be falling like a bat out of hell. Wouldn't it be something if the recent melt-off slope sustained until it intersected the 2012 line? Dramatic, anyway, for us climate nerds!
Posted by: David Goldstein | July 04, 2013 at 08:50
With regards to the effects of ice versus open water on melt, as i understand the problem there are different rates in play:
1. Rate of heat loss from open water under varying conditions of weather and sea temperature.
2. Rate of heat absorbtion from sunlight of ice versus water.
3. Heat transfer rate from seawater to ice above it.
4. Melt/Freeze rates of ice/water.
This seems like the arctic version of the coffee cooling problem: when to add milk to get the coffee cool enough to drink the fastest (or retain heat longest if you are a commuter.)http://www.loreto.unican.es/Carpeta2007/00TorreonCartes2007/CafeyLeche.pdf
This seems like it should have been solved already, at least theoretically as an engineering problem.
Posted by: Fufufunknknk | July 04, 2013 at 08:52
Looking at the AO Index for the past three months it's clear that set-ups 2 and 3 have been dominant:
But despite this area and extent numbers have been dropping fast in the past two weeks.
Posted by: Neven | July 04, 2013 at 08:56
Maybe this link explains what i meant better.
http://www.thenakedscientists.com/HTML/content/kitchenscience/exp/-0c2ee7e805/
Only instead of milk cooling the coffee by mixing, ice can be thoguht of as a layer of milk poured on top of the coffee that initially is at the same temperature as the coffee.
Posted by: Fufufunknknk | July 04, 2013 at 08:57
We've been falling rapidly during the last few days on extent, but it seems most is in the Hudson/Kara with some melt in the Beaufort (its about time!) in the most recent scan.
I was comparing this year to higher extent years like 2009, and that year was so much more ice in the Hudson and a little bit more in the Kara. Even some of the lower extent years had more in the Hudson than now. This makes me want to see more melt in the coming weeks to believe it will truly catch up. Comparing this year to recent years on the concentration maps, those other years still look like they were in a lot worse shape.
Maybe we'll see a huge melt this week. But pardon me for not believing that we all of the sudden will catch those years so soon. I remember people talking about the Beaufort going pretty sloppy by the last week of June based on their webcam images from the buoys and that didn't happen obviously.
Posted by: Henry1 | July 04, 2013 at 10:02
Of course, this speaks for itself. I'm not saying that 2013 is going to catch up. I'm saying that it shouldn't be ruled out as of yet. There's a lot of melting potential out there, and we're still only halfway through the melting season.
I personally think that with a period of the 1) set-up described above in weeks to come, 2013 could come close to 2012.
Whatever happens, for the longer term, I'm suspecting that this year won't drop significantly below (or at all) the volume minimum of last year, due to that slow start to the melting season. Maybe this will give the MYI north of Greenland and the CA a chance to catch its breath.
Posted by: Neven | July 04, 2013 at 10:13
Maybe the start wasn't slow at all, maybe it was too fast in the beginning- Correct me if I'm wrong, but melting started at the and of March and in April extent and area both were below 2012 and we saw some century area-breaks in April.
As poster "ktonine" suggested at the forum ( https://forum.arctic-sea-ice.net/index.php/topic,92.msg8689.html#msg8689 ) , maybe the unusually coolness came from the cracking event.
And perhaps the dispersion of little ice floes fooled the satellites.
We will see soon how things work out - if 2013 would beat 2012, we will have to discuss this further.
Posted by: wanderer | July 04, 2013 at 11:10
Here are some recent temperatures from places around the Arctic basin:
THULE, GREENLAND – 9C
KUGLUKTUK, NUNAVUT, CANADA – 3C
LONGYEARBYEN, SVALBARD – 11C
BARROW, ALASKA, USA – 7C
CAMBRIDGE BAY, NUNAVUT, CANADA – 3C
http://www.athropolis.com/map2.htm
That seems fairly warm for this time of year. Surrounded by warming land, what will the ice do and how long will the melt season last this year?
Posted by: Kate | July 04, 2013 at 11:25
PIOMAS update:
Latest value: 2013-6-30 13.002
I have updated my graphics at ArctischePinguin for the latest data.
Monthly Data
Daily Anomalies
Daily data
Daily data with a "prediction" based on exponential trend
Posted by: Wipneus | July 04, 2013 at 11:32
Hi Neven,
thank you for that interesting post. But I do not understand, why in high pressure (clockwise blowing winds) the ice will push together and on the other hand in low pressure (anti-clockwise winds) will disperse the ice... In the Atmosphere the wind ist blowing to the center of a low pressure area - and out in high pressure. Does ice has a different moving? Or is it just a mistake in the picture?
Posted by: KSchwanke | July 04, 2013 at 12:07
KSchwanke
The Earth's surface is always traveling towards the east but in the northern hemisphere continually turning towards the north to keep it on a circle of latitude.
Clockwise motion of the ice (relative to the Earth's surface in the northern hemisphere) means that the ice is traveling faster than the Earth and finds it harder to make the 'northwards turn' so drifts southwards (relative to the Earth's surface).
Posted by: GeoffBeacon | July 04, 2013 at 12:33
@GeoffBeacon
And this is what led to thick multiyear ice piling up along the north coast of Greenland, yes?
And now this ice is starting to thin and move than before? No buffer?
Posted by: Kate | July 04, 2013 at 12:37
KSchwanke: http://en.wikipedia.org/wiki/Ekman_spiral .
Posted by: Remko Kampen | July 04, 2013 at 14:19
KSchwanke, note that the Coriolis force is perpendicular to the wind speed. High above the ground, the moving airmass follows the isobars since there is a perfect balance between pressure gradient force and coriolis force over every given element of the airmass. There has to be so, because (ideally) there are no other forces.
However, close to the ground, the pressure gradient force must also balance the friction force that arises between the displacing airmass and the ground. Note that the friction force goes parallel to the wind direction, not perpendicularly. In this case, the pressure gradient force has to balance out the sum of two components, one perpendicular and one parallel to the wind vector. The wind direction close to the ground cannot go along the isobars anymore; it rotates toward the low pressure side in order to make possible a perfect balance of friction, coriolis and pressure gradient forces.
Posted by: Account Deleted | July 04, 2013 at 15:02
KSchwanke
Air tries to move from high pressure to low pressure but the Coriolis effect, which is greatest near the poles and decreases to zero at the equator, deflects it to the right in the Northern hemisphere.
This is the reason air rotates clockwise round areas of high pressure in the Northern hemisphere - it's trying to move away but is continuously being deflected to the right. Similiarly air rotates anti-clockwise round areas of low pressure because it is trying to move towards the low pressure but is deflected to the right. BTW the reason you don't get hurricanes at the equator is because there is no Coriolis effect there.
The wind will push the ice in the direction it's blowing, but the Coriolis effect will deflect the ice to the right, which is why the net effect of clockwise rotating winds is to push the ice towards the centre and and the net effect of anti-clockwise rotating winds is to push the ice away from the centre.
Posted by: kalagas | July 04, 2013 at 15:42
So yes KSchwanke, just as you said, continuing my reasoning, the air close to the ice/ocean surface is slightly moving toward the center of the low due to the friction between air and ice/ocean surface. So I am very perplexed. Why is the ice then diverging below a low-pressure cyclone? Don't bother, Wikipedia pages don't help much.
Posted by: Account Deleted | July 04, 2013 at 16:57
I like the big picture, and taking from your headline post Neven, is in spite of weather not conducive to great melt this year, low ice volume (thin ice) may support a melt not much different than 2012. If so, then it is just a matter of having a year with weather favorable for a lot of melting to get the first ice-free Arctic.
After the slow start, if 2013 comes anywhere near 2012, it would certainly back up that point.
Posted by: Hans Gunnstaddar | July 04, 2013 at 17:16
It would be nice to have the usual Barrow sea ice breakup report. It was in the top 25% (I believe), for early breakup, but the analysis of W/m^2 is not there.
It would have been very interesting to see the difference between, say, 2004 which also did not have landfast ridges. To show what the difference is in W/m^2 required to melt the ice out so early.
Because if the ice is melting out with much less insolation, then this is a key statistic in the picture.
Posted by: NeilT | July 04, 2013 at 17:21
Yes, that's one of the possible outcomes of this melting season.
Another possible conclusion, when 2013 stays not only above 2012, but 2007/2011 as well (or even 2010), is that the start of the melting season is extremely important, even when the ice is thin on average.
This could then be an example of how a recovery starts, presuming that something overwhelms the global warming signal and cuts off heat transport towards the Arctic.
Posted by: Neven | July 04, 2013 at 17:26
Correction to earlier post: Aniticlockwise motion of the ice (relative to the Earth's surface in the northern hemisphere) means that the ice is traveling faster than the Earth.
Posted by: GeoffBeacon | July 04, 2013 at 17:47
I looked at different regions of the Arctic using Cryosphere Today to find out why the melting has picked up recently.
After looking at all the different regions, I found out that the biggest contributor to the recent drop is the... area around the Hudson Bay which is ice free by the end of summer.
Even though we are seeing 2013 finally starting to get in the race, I don't think this fast decline that we have been seeing the last few days will matter by the melt season's end if most of the melting is happening in areas that will be ice free by the end of the season.
A fast decline in which an important region such as the East Siberian Sea is the main contributor will be more interesting to look at since the East Siberian Sea is an area that isn't supposed to be ice-free by the end of the melt season.
Posted by: IcyMountain | July 04, 2013 at 18:16
The persistent Polar Cyclone PAC-2013 was introduced by the latest Sudden Stratospheric Warming March ’13. For what I gather to be the situation, it is part of a global reset of atmospheric conditions. I suggested in April that, maybe, this NH summer the Arctic wouldn’t be the premier eyecatcher for the phenomena illustrating this reset. That perhaps the mid-latitudes would.
And haven’t they?
The looping and stalling jet gave Western Europe the coldest spring in 30 years. Meanwhile, Eastern Europe experienced one of the warmest. In between, the Elbe and Danube Basins were drowned. While Greenland got hold of a persistent through (I’m not really checking on Sermeq Kujalleq), in a follow-up of two weeks , extreme ridging hit respectively Alaska and the American West, crushing Alberta in between with major flooding. The latest theatre is the Atlantic seaboard with a constant drenching of tropical rains.
Interesting enough, we haven’t heard much of Asia’s mid-latitudes. A, maybe, cherry-picked detail is the anomalous algae growth, reported by the BBC today, in the seas of Eastern China.
Posted by: Werther | July 05, 2013 at 00:51
Werther I live in south China and the Western press generally cherry picks things to report about China that make China look bad.
last winter it was unusually warm here in the south and unusually cold in the North East.
people here were complaining about the heat in December.
Posted by: philiponfire | July 05, 2013 at 02:55
entering "cold winter in north east china" on Google got me this link first try.
http://www.livescience.com/26095-china-cold-winter-weather.html
Posted by: philiponfire | July 05, 2013 at 02:59
Werther, what do you make of the doubled jet described here?
Posted by: Steve Bloom | July 05, 2013 at 04:53
Neven, you wrote; "Another possible conclusion,..."
Yes, after 2012 record melt, less MYI ice (thinner), broken up ice from cyclone and slow 2013 start, this grand experiment is bound to offer up some interesting post analysis one way or the other.
IcyM, you're discounting the recent drop in 2013 extent, however chart-wise it's about the same declination as 2012, just later, and if you notice 2012 then starts paralleling 1979-2000 average, so I'm inclined not to discount this drop as much wherever the melt is primarily coming from due to thinner and worse conditioned ice. Just fascinated watching to see where the new line ends up.
Posted by: Hans Gunnstaddar | July 05, 2013 at 05:54
Where are we getting the idea that the ice condition is worse than 2012? Outside of that area near the pole that is.
Volume is above 2010 now, nevermind 2011 and 2012. I can see getting some crappy ice floes pretty far into the arctic basin in the end, but this still doesn't explain how we make up 1,000,000+ sq km in area deficit on the 2012 melt. It feels like a leap of faith.
Posted by: Henry1 | July 05, 2013 at 06:20
Morning Steve,
I got a result like the pic in your link through NCEP/NCAR on zonal winds through June. That was one factor to post on enhanced turbulency/energy input in the Arctic.
For the numbers, just enjoy the ride and don't read too much in them. MODIS will show...
Posted by: Werther | July 05, 2013 at 06:57
Henry,
I agree.
Posted by: Chris Reynolds | July 05, 2013 at 08:07
as of day 183 the deficit is about 780,000sq km, where are you getting 1,000,000+ Henry?
that much is going to be gone and more within the next two weeks.
both Hudson bay and the Kara are covered in a skin of slush that together amounts to half of your deficit.
NSIDC says that the ice in the Beaufort sea was all between 1 and 1.5 meters thick when they looked with "icebridge". oops there goes another 200,000 off the deficit.
while a higher figure is possible it is still likely that we will see a September figure close to or even surpassing 2012
Posted by: philiponfire | July 05, 2013 at 08:57
I was going by Chris Reynolds' anomaly graph with CT area. I think you have to use day 184 for 2012 since it was a leap year. The anomaly graphs shows 2013 1,000,000 sq km ahead.
Assuming the Beaufort melts out doesn't mean the arctic basin is going to melt like 2012. The Beaufort taking its time is going to help the arctic basin retain more side on that side. What happened to all the positive feedbacks with open water we talked about? They don't exist anymore because the ice is behind schedule?
Maybe you will be right, but I haven't seen a good argument yet. I guess we'll all know together in 60 days.
Posted by: Henry1 | July 05, 2013 at 09:04
To echo philiponfire...
Let's go back a ways; 2007 in fact, and have a look at buoy 2006C, a favorite image of mine.
http://imb.crrel.usace.army.mil/2006Csum.htm
I'll draw your attention to the brilliantly colored thickness/temperature graphic.
2006C spent a significant portion of its life in the Beaufort. In 2007, from July 1, to the 1st week of September, it showed a drop in thickness from about 300CM, down to about 120 or so. The bottom melt really did not start in earnest until well after the May/June melt. During that same period, it went through almost 75CM of top melt. 255CM of melt, all told.
Considering that Air Bridge estimated that most of the Beaufort *started* the season at between 1 and 1.5 meters, this really doesn't bode well, at all, for the Beaufort ice surviving the melt season, *even* *if* we have fairly favorable conditions, which we decidedly, do not. I'm pessimistic.
July is going to be interesting to watch.
Posted by: jdallen_wa | July 05, 2013 at 09:33
Well it has certainly proven to be a very 'interesting' season so far?
I just cannot figure how it will go over the next 70days but know that whenever the ice melts, be it july 10th or Sept 10th it is no longer there on extent/area plots?
Unlike other years we see the central basin pretty bashed up with it's albedo lowered in a way I don't think we have ever witnessed before? This area has the 'shortest' melt season but does it's current condition mean that we will see far bigger losses there than we are used to? Other sea areas are holding onto far more ice than we are used to seeing ( since 07' ) but experience tells us that these areas 'melt out' over 'average summers'? We may be used to seeing the areas 'ice free' by early Aug but what does it matter if it is 'late Aug' by the time the ice goes?
The forecast 'melt friendly' period of weather will give us some clues as to what we should expect of the basin?
In past years I have looked to the CT concentration map, at the start of Aug, to see the 'shape' of the ice that will be left at seasons end ( only the highest concentration areas normally survive?) but I think this year this method might not prove as useful??
Posted by: I Ballantinegray1 | July 05, 2013 at 10:34
'Northwest Passage as good as open' article was on 31 July last year. With Nunavut colder than historic averages and while last year recorded above average temperature it is interesting to see how melt progresses. We may still see an earlier date of opening this year.
Posted by: Batyek | July 05, 2013 at 10:40
http://lance-modis.eosdis.nasa.gov/imagery/subsets/?subset=Arctic_r04c02.2013185.terra.250m
the nothwest passage looks like a shattered car window and just as transparent. be that thin ice or melt ponds that ice has no long term future.
the location of Nunavut suggests that the land in between would create two separate micro climates. I will be amazed if the NW passage does not melt out.
Posted by: philiponfire | July 05, 2013 at 10:57
For more on Donald Perovich's "brilliantly colored thickness/temperature graphic" from 2006C head over to the forum and check out "What the buoys are telling us"
Amongst other things, bottom melt on 2012J appears to have started quite some time ago, and things in the Beaufort are now kicking into gear too.
Posted by: Jim Hunt | July 05, 2013 at 10:57
my comment about nunavut makes no sense sorry a google maps misunderstanding sorry
Posted by: philiponfire | July 05, 2013 at 14:29
A little off topic,
Catalyst, a science program from the ABC in Australia,
has done a nice little segment on the effects of the warming climate and melting sea ice on the weather.
http://www.abc.net.au/catalyst/stories/3796205.htm
Now back on topic. "Why is the ice then diverging below a low-pressure cyclone?" You can think of it this way.
Because the earth is rotating counter-clockwise about the north pole, the Ice is also rotating. So it is subject to centrifugal force.
The Low (because of the counter-clockwise winds) is acting to speed up the Ice, thereby creating more centrifugal force, hence greater divergence.
The High acts as a 'brake' on the ice, reducing the centrifugal force, and making the ice more compact.
philiponfire: I See what you mean about the NW passage, it looks rather - blue. Doubt that ice has much time left.
Posted by: Sunkensheep | July 05, 2013 at 15:57
So, sunkentsheep, do you think that the donut hole is being maintained near the pole by the earth's 'centrifugal' force?
(Wiki reminds us that it only an "apparent" force, hence the quotes; but it is too handy a term to discard, since everyone knows what it refers to.)
With the ice pack becoming more and more broken up and slushy, do you think we can expect this to become an ongoing, consistent feature of the ice pack in future years (until there is no ice pack to form holes in)?
Posted by: wili | July 05, 2013 at 16:33
In the June 1st round of Piomas, note Feb, March, April, May and now June have flattened the last three years and give a much longer extrapolation date to zero ice pack than the more immediately relevant Aug, Sept, Oct cluster. Since we cannot have two expiration dates, we are looking here at systematic error (volume over-estimation) in spring Piomas.
Like everything else, Piomas is ultimately pegged to remote sensing microwave imagery whose interpretation has never been seasonally calibrated.
Note the choice of exponential fit is not a plausible alternative explanation -- this makes physical sense from its underlying differential equation (unlike Gompertz) and as a practical matter amounts to a second order expansion -- short taylor series, over the short term, are topologically dense in the conventionally metrized space of plausibly relevant differentiable functions.
I question whether the Beaufort - Chukchi - East Siberian Sea corridor is really behind or is just taking a different path. It is a mistake to take the size of a single patch of open water off the Mackenzie as the proxy for melt season. The freeboard in recent buoy images is minimal and, more comprehensively, all 28 channels of Suzaku microwave establish that almost the whole enchilada is in advanced melt stage.
I've attached just one frame of that for now, the 04 July 13 6 Ghz horizonally polarized ascending.
Posted by: A-Team | July 05, 2013 at 16:46
So the orange areas are the MYI remnants, the yellow ones are compacted FYI, and the rest is more or less rotten ice?
Posted by: AmbiValent | July 05, 2013 at 17:15
Sunkensheep is right about that Catalyst program. Highly recommended as a good summary on the whole 'Extreme Weather" question.
On the divergence/convergence question, I'll offer my 'mental model,' FWIW.
Background:
1) Coriolis 'force'--purists insist it is not a 'real' force--arises because the Earth's surface rotates at speeds that are a function of latitude: the farther poleward you go, the lower the rotational speed, until at the pole it approaches zero asymptotically. (Hope I'm using that term correctly for math purists.)
2) For the Northern hemisphere, lows (cyclones) spin counter-clockwise (anti-clockwise in the UK and various former colonies), while highs (anti-cyclones) spin clockwise. (In the South, that is reversed.)
That's the 'background' part. Now for the 'process':
1) Imagine an 'air packet' in a Northern cyclone--let's picture it at the Eastern arc of the system (the '3 o'clock' position, as viewed from above.) The clockwise spin is moving it to the South. But the surface is spinning Eastward beneath it, which implies that it has an Eastward component to its motion as well.
As the air packet moves South, its Eastward component does not immediately increase--but the effective Eastward component of the surface does, since that Southward movement of the air implies that the air is moving away from the Pole--that's Background Point #1 in action. The air packet consequently 'falls behind' the Eastward rotation of the surface. From the point of view of the surface, the air packet appears to be deflected to the West--that is, to the right.
2) Soon enough, the packet is moving Westward, despite the effects of friction with the surface. One might think that the process stops here, since there is no more motion of the air relative to the pole. (I suppose it would also be proper to call this "meridional flow," from what little I know of meteorology.)
But the process continues. Why? One answer is that the air packet is not a geometrical point; it is a physical mass with some physical dimension. As it moves Westward, its right is Poleward of its left.
As it happens, the Coriolis deflection is strongest at the Poles, and zero at the equator. That makes sense, if you think carefully about it: at the Pole, the land's surface is effectively perpendicular to the Earth's axis, so motion is initially 100% away from the Pole. But the other extreme is the Equator: there, motion has a 0% Poleward component because the surface is effectively parallel to the axis of rotation.
So, if the deflection is proportional to distance from the equator, and our adopted air packet's right is farther from the equator than its left, then its right is more strongly deflected right than is its left. Insofar as the packet behaves as a body, it will acquire a rotational component--yes, to the right.
As we follow the packet around the circuit, the Northward leg will be a mirror image of the Southward, and the Eastward of the Westward. The Coriolis forces operates in all directions (though not to the identical magnitude: the Eastward leg of the circuit should be the most strongly affected, since it occurs closest to the Pole, while the Westward leg should be the least affected.) Voila!
Finally, let's consider the sea ice. Initially I had the same question as many of the commenters above. I had tacitly assumed that since circulation arises in part from the Coriolis force, that the ice motion should be 'factored in,' which renders the deflection of the ice problematic. But you can't 'factor in' a force that is only apparent in the first place.
The sea ice is only truly impelled by the wind (and of course, any tides and currents that may exist, but we'll just concentrate on the winds.) So, supposing our air packet to be pushing sea ice on the surface, we must remember that the Coriolis deflection applies 'separately' to the ice. It will be deflected to the right of the wind direction.
This was observed first by the Arctic explorer Nansen:
http://polar.ncep.noaa.gov/mmab/papers/tn114/OMB114.pdf
Posted by: Kevin McKinney | July 05, 2013 at 17:26
Previewed my lengthy comment a half-dozen times and still had to post it before I noticed that the "degree" signs weren't displaying.
So, when you read the comment--and I think it's in the spam filter, so this corrigendum may show up first--take note that in the Grumbine blockquote the drift law numbers are glitched. Nansen observed 28 degrees, Thorndike & Colony only 8 degrees, and Martinson & Wamser 23.4 degrees. (The actual numbers aren't that significant, but the magnitudes and units are helpful in reading the comment, when Neven can retrieve it for us.)
Posted by: Kevin McKinney | July 05, 2013 at 17:34
This link will take you to a cropped polar stereographic view of Suzaku microwave from which you can navigate to various ascendencies and polarities.
This satellite is part of the A-train (A for afternoon) and so its images are essentially synchronous with the others (notably Aqua, CloudSat and Calypso which are 4, 6'30" and 6'45" minutes behind GCOM-W1 respectively). We should be making much greater use of CloudSat and Calypso which really are the future of observational monitoring the altered heat budget of the Arctic Ocean.
Right, a NW passage has been melting very rapidly this spring as seen from Suzaku 18V 36VH (which we've been calling colored Jaxa). I've attached that and a 10 Ghz horizonal ascending for 04 Jul 13 -- on both, look for a fiducial area where you know the ice status and see what else is that color. Some thick ice is holding out in the Barrow Strait below Resolute.
Like open water at the North Pole, an open Northwest Passage is newsworthy (graspable by the general public) but not a significant proxy for the overall state of Arctic sea ice.
Posted by: A-Team | July 05, 2013 at 17:36
Nice start there on interpretation, AmbiValent.
It is easy enough to animate weekly spaced images since the Sept 2012 minimum and so track the history to better validate (or not) the 'compacted first year ice' and other regions of interest.
The Navy Hycom forecast -- which we somewhat like but don't expect to be perfect -- is not getting the region below Svalbard that connects to the region affecte by the persistent cyclone in the central polar region.
I don't expect to see the predicted post-cyclone viscoelastic relaxation for this coming week, for the reason Chris gave (historic tensile strength of ice too high in model) or just looking at R04C04 Modis visible 500m, there isn't any coherence in a region of open floes.
However the MYI will spread out substantially later in the season as it warms and buttressing vanishes. The goat's head (which is still around but barely visible) was pushed by spread almost to Siberia last summer.
Posted by: A-Team | July 05, 2013 at 17:55
I prefer to stay loyal to R. Gates' "toast theory" (everything outside his yellow line is toast). High pressure is allready taking over in the arctic and although one should be carefull with arctic weather forecasts going beyond 120 hours, an anticyclone with 1030-1035 hPa now looks likely to appear, opening the floodgates for warm Siberian and Alaskan air masses. 15 days from now millions of square km vil be colored green and yellow on the CT maps and after another 15 days practically the entire East Siberian Sea as well as large parts of the central basin will be nothing but open water. Only a miracle can save us from another record spree this year.
Posted by: Doomcomessoon | July 05, 2013 at 18:01
I readly like this way of presenting the state of the ice.
ftp://ftp-projects.zmaw.de/seaice/AMSR2/Arc_latest_yesterday_AMSR2_3.125km.png
Posted by: philiponfire | July 05, 2013 at 18:05
It's a rather amateurish interpretation. I just thought that Beaufort and Chukchi were the areas where the ice broke apart in winter and froze together again (with the interim open water contributing to areas with thin ice cover). And ice would have only compacted if pushed against land, be it islands or the coast (or the MYI, which leans against Greenland and the Canadian Archipelago), and the yellow areas seem not too far away from those areas now (months after the supposed formation).
But I'm curious about what the experts will say.
Posted by: AmbiValent | July 05, 2013 at 18:23
A Team,
"Since we cannot have two expiration dates, we are looking here at systematic error (volume over-estimation) in spring Piomas. "
It's not an overestimation, it's an uptick due to weather which by June has become highly unusual.
Posted by: Chris Reynolds | July 05, 2013 at 18:44
Henry, you wrote in response to my last post above, "It feels like a leap of faith."
However what I wrote was, "...this grand experiment is bound to offer up some interesting post analysis one way or the other."
One way or another means plus or minus, not requiring of 'a leap of faith'. In fact my prediction 1st and 2nd time was and still remains 4.35, so I am not of the perspective of a drop from 2012 but rather a rebound.
What is fascinating though is the recent sharp drop in ice extent as it pertains to those that have predicted a new record low this year.
Posted by: Hans Gunnstaddar | July 05, 2013 at 19:23
Neven- I'd concur with OLN on his assessment of your writing abilities. Being able to communicate through writing on a subject many Americans don't grasp is extremely valuable. Keep it up.
Posted by: Craig Merry | July 05, 2013 at 19:27
A-Team, I think that Wipneus graph shows the projected year for zero ice in all different months, not different predictions of the first zero. July through November shown ice free by 2020.
Posted by: Ian Allen | July 05, 2013 at 20:02
On the graph “hor. Polarised ascending 6GHz”posted by A-Team, 16:46 h today.
AmbiValent, I think the microwave reflection doesn’t enhance MYI, but areas with remaining snow cover on the ice.
Compared to the ASCAT images I put on the Forum “medium to short term…”, I’m under the impression that the scatterometer has more grip on moisture content. Please correct me if better info is at hand. For good interpretation, this sort of info is badly needed.
A-Team, the travels that you suggest for ‘Goat’s Head’ don’t fit my view that the feature originates in the 2011 Siberian Arm, so well described by Neven then. Since, it has crossed over all the way.
To illustrate: I have this in my files:
The remarkable form was already there …
BTW the green line is, of course, the ’07 minimum.
Posted by: Werther | July 06, 2013 at 00:10
I am amazed that the DMI Arctic temperature reanalysis remains so cold! (Took another minor downward dip today, and remains well below seasonal norms.)
Posted by: Kevin McKinney | July 06, 2013 at 00:56
I'm amazed that extent is dropping like a stone in spite of cold temps and increased volume, http://nsidc.org/arcticseaicenews/
If, (and I realize that's a big if), it doesn't change graphical direction, 2013 will intersect 2012 about July 10-12.
Posted by: Hans Gunnstaddar | July 06, 2013 at 02:15
I notice something strange in the concentration map here
ftp://ftp-projects.zmaw.de/seaice/AMSR2/
Arc_latest_yesterday_AMSR2_3.125km.png
There seems to be a 'reflection' of the CAA land mask in the Ice cover on the 'opposite' side of the Arctic. I'm assuming its an image processing problem.
Kevin: seems like a reversal of the 'warm arctic cold continents' pattern.
Posted by: Sunkensheep | July 06, 2013 at 02:35
This may be a silly question, but if the arctic has been colder than normal since winter, and continues to be cold even now, then shouldn't we expect to see a return to a more normal (or what used to be normal) jet stream this year? Instead we're seeing an unusual double jet stream. Or is the cold arctic air a result of that double jet stream, and too confined by it to influence the entire NH, and thus unable, on its own, to re-establish a more 'normal' jetstream?
Posted by: james cobban | July 06, 2013 at 03:05
Perhaps so, sunkensheep. But it's quite unusual in the context of recent years. Perhaps I should look back a bit in their archive.
Posted by: Kevin McKinney | July 06, 2013 at 04:32
Well, after a quick look back in the archive, I really don't see anything quite so marked in the last 30 years--though 2009 perhaps come close.
Posted by: Kevin McKinney | July 06, 2013 at 04:51
Sunken sheep:
It is in the data as well. Applying a new feature, an "ocean mask" was not implemented too well. I have notified the U-Hamburg people.
See also the new README that was put in that ftp directory.
Until corrected no updates of my derivative works :-(
Posted by: Wipneus | July 06, 2013 at 08:32
Wipneus, say it ain't so!
Posted by: Neven | July 06, 2013 at 10:14
Neven:
The good news is that the SSMIS 12.5km data has started to come in again.
Unless "ocean masks" are going to to be applied there as well, I can make regional graphs from the SSMIS data as well.
Posted by: Wipneus | July 06, 2013 at 11:27
"This may be a silly question, but if the arctic has been colder than normal since winter"
Far from silly. About 2-3 months ago a poster stated in another thread (can't remember which one, sorry) that the Arctic temperatures would remain cold for as long as the temperature anomaly off the Pacific side of the South American coast remained cold. I have followed this anomaly (ENSO in La Niña state?) since, and it does appear to correlate to the low Arctic temperatures. These are the two maps I check, this one http://www.esrl.noaa.gov/psd/map/clim/sst.shtml
vs surface temperature anomalies.
Posted by: Climate Changes | July 06, 2013 at 11:33
Wipneus, that's great, but like Aaliyah once sang: We need a (better) resolution.
Posted by: Neven | July 06, 2013 at 11:35
Good spotting. They have the land mask mirrored about the horizontal meridian, then over-ridden by the continental mask. Not just CAA masking data in Siberia -- Siberia masking CAA as well.
To highlight a second issue that comes up all the time, I've colored the 100% sea ice concentration green and 95%-99% yellow.
That is, it's very difficult to distinguish the regions of subtle melt in their palette by eye.
In scientific publishing outside the field of climate science, the image provider would be required to supply the areal percentages in each palette class.
Plenty of room here to place that on the land mask as a courtesy to the image user (or provide as comma-delimitd excel row). But here we are again, 500 viewers clicking through a 100 bar palette determining the histogram for themselves -- 50,000 clicks of wasted time, every day.
Posted by: A-Team | July 06, 2013 at 15:15
Isn't the air temp always depressed in the vicinity of rapidly melting ice? That's certainly been my experience jogging (well, ok, walking briskly) around Lake Calhoun every spring. Is it too simplistic to observe that adding more energy doesn't raise the temp much above freezing as long as there is still unmelted ice?
Posted by: epiphyte | July 06, 2013 at 20:17
Chris Dickson wrote:
No, it's not simplistic, Chris--it seems to this layman to be pretty well accepted that this is just the mechanism that 'clamps' Arctic surface temperatures to relatively low values every Arctic summer.
But that can't be what's happening this summer: the temps are significantly and relatively consistently lower than usual, and there's no more melting going on; in fact, there has been less than in recent years until relatively recently. (I'm guessing that the causality runs: atmospheric circulation causes low temps causes slow melt.)
I don't want to make too much of it, because chances are that 'it's just weather.' But even weather has reasons, and it would be interesting, at least, to have some sense of what those reasons might be.
Posted by: Kevin McKinney | July 07, 2013 at 06:01
when the water temperature climbs above -1.9 C, towards 0.0 C, the sea water starts melting more ice from the bottom than freezes back. So the surface air temperature doesn't have to be at or above zero C for the ice to melt from underneath, as long as the sea water is above -1.9 C, maybe around -1.7 C, there will be net melting (absent frozen precipitation). And faster water movement increases the rate of bottom melt.
The surface air temperatures this summer could be dominated by the melting/freezing process with the sea water; more so this year than any other year on record. The ice itself conducts heat, especially when it has no snow cover and/or is thin. And the ice is so thin.
The center of the ice pack (and the rest) is probably "toast," in my opinion. If I wanted to start the sea ice off on a path towards maximum melt, blasting the middle at the start of summer would probably be a top choice, along with increasing summer rainfall.
Posted by: Fairfax Climate Watch | July 07, 2013 at 08:30
Kevin,
The DMI 90 deg+ temp record from spring and summer so far 2013 is not much related to ice melt. In fact, 2004 and 2007 show very similar paths so far (with 2007 diverting with a quick peak in early June).
On the other hand, who remembers the scorching Artic summers of 1971, 1981 and 1985 where DMI clearly shows above average temps throughout the summer ?
Of course, DMI's 80 deg+ temp record is pinned down pretty close to the melting temp of snow (0 C).
However, if there are open areas of ocean water above 80 deg (such as the holes we are seeing right now) the DMI 80 deg+ temp would naturally be pulled down a bit closer to the -1.5 C of salt water.
May that explain why 2013 (and many other years in the last decade) show a DMI temp slightly below average ?
Posted by: Rob Dekker | July 07, 2013 at 09:00
That said, DMI shows that above 80 deg, the Arctic basin started top-melting late this year.
The question is : how much does that matter ?
We have significant holes in the ice above 80 deg, due to the very cause of the late melt (to 2013 PAC), and these holes will grow and weaken the ice in the Central Basin more over the melting season, possibly leading to "burning a hole" in the NP area.
Right now, 2013 in terms of ice extent, area and (modeled) volume is quite similar to 2010/2011. So will it end up in that area in September ?
Since in many ways the 2013 situation for the Central Arctic is quite opposite from the 2012 situation, this year may be a great test to see how much the influence of "weather" still is on the Arctic...
Posted by: Rob Dekker | July 07, 2013 at 09:14
Re: U-Hamburg amsr2 concentration error. The error was corrected, I have started updating my maps and area/extent calculations.
Posted by: Wipneus | July 07, 2013 at 10:23
That's great news Wipneus. THANKS!!
Posted by: OldLeatherneck | July 07, 2013 at 13:52
Here I 'melted' the sea ice concentration starting with 06 Jul 13 (UHH AMRS2 L1R Jaxa) with successive parabolic intensification of the palette. This might approximate how the ice will look in future weeks assuming no wind and that sea ice concenteration continues to drop where already started. The second (more dramatic) version is inverted in color.
The palette score data for the original image is provided below in comma semi-colon delimited format. These range from 44.8% of the ice at 100% concentration to 8.3% open water, for the Arctic Basin and CAA as masked. It would be feasible (started from a numerical array view) to make a time series of how the concentrations change over the melt season, say by animating the width of the palette bands.
100,44.8;99,7.7;98,5.3;97,4;96,3.1;95,2.5;94,2;93,1.7;92,1.5;91,1.2;90,1.1;89,1;88,0.9;87,0.8;86,0.7;85,0.8;84,0.7;83,0.6;82,0.6;81,0.5;80,0.5;79,0.5;78,0.4;77,0.4;76,0.4;75,0.3;74,0.3;73,0.3;72,0.3;71,0.3;70,0.3;69,0.2;68,0.2;67,0.2;66,0.2;65,0.2;64,0.2;63,0.2;62,0.1;61,0.1;60,0.1;59,0.1;58,0.1;57,0.1;56,0.1;55,0.1;54,0.1;53,0.1;52,0.1;51,0.1;50,0.1;49,0.1;48,0.1;47,0.1;46,0.1;45,0.1;44,0.1;43,0.1;42,0.1;41,0.1;40,0.1;39,0.1;38,0.1;37,0;36,0.1;35,0.1;34,0.1;33,0.1;32,0;31,0.1;30,0.1;29,0;28,0.1;27,0.1;26,0.1;25,0.1;24,0.1;23,0.1;22,0.1;21,0.1;20,0.1;19,0.1;17,0.1;16,0;15,0.1;14,0.1;13,0.1;12,0.1;11,0.1;10,0.1;9,0.1;8,0.1;7,0.1;6,0.1;5,0.1;4,0.1;3,0.1;2,0.1;1,8.3
Posted by: A-Team | July 07, 2013 at 17:29
The clouds finally lifted yesterday between the New Siberian and Wrangel islands -- a large region that has been continously obscured from observation for 4-5 weeks but is now seen to have melt well underway.
It appears that the sea ice concentration (and every similar and downstream product such as Piomas) may have been underestimating the extent of melt because they simply have not had good remote sensing access to the ice.
Posted by: A-Team | July 07, 2013 at 18:05
Some rather striking melt action the last 8 days around Svalbard, Franz Josef, Kara Sea and Siberian rivers...
Posted by: A-Team | July 07, 2013 at 19:48
A-Team: The beginning of a 'flash melt' phenomenon, perhaps?
Posted by: wili | July 07, 2013 at 21:52
A-Team said: "This might approximate how the ice will look in future weeks assuming no wind and that sea ice concenteration continues to drop where already started. "
Looks about right, I think.
A-Team also said: "Some rather striking melt action the last 8 days around Svalbard, Franz Josef, Kara Sea and Siberian rivers..."
Looking at the animation, I'm struck not just by the ice disappearing, but by it simultaneously retreating and spreading out (looking at the Kara directly below the tip of Nova Zemlya) So aside from just melt and retreat, I think the image suggests over-all decreases in concentration in the surviving extent as well.
Posted by: jdallen_wa | July 07, 2013 at 22:12
PAWS 975420 has shown the warmest temperatures of this melt season these last two days and has also seems to be making a rapid shift toward the Fram.
87.023°N 1.195°W 0.7°C 1008.4mb
http://psc.apl.washington.edu/northpole/PAWS975420_atmos_recent.html
Posted by: Jai Mitchell | July 07, 2013 at 22:41
A-Team - thanks again. Great work.
I would also note the predicted/anticipated thinning poleward from Greenland and Ellesmere. In previous years, this was home to some of the oldest MYI. If that ice goes ungrounded, might it also be swept toward the Atlantic.
If the past is any indication, we should expect the ice 'north' of the Northwest passage to go. If so, the only remaining grounded MYI ice may be over the western end of Ellesmere.
What exactly happens when the majority of ice is badly fractured and comes ungrounded in the central arctic? I guess we may soon find out.
Sam
Posted by: Sam | July 07, 2013 at 22:48
Sam, that's about my assessment as well.
Looking at Wipneus' geospatial prediction of Arctic sea ice zeroing out -- based sensibly enough on exponential decay of each individual Piomas cell 1979-2012 -- shows remnant ice seemingly too far to the east and most improbably in the Fram.
This artifact may arise from steady-state export of multi-year ice, putting it in the Piomas crosshairs. The real refugium from the Beaufort Gyre and Transpolar Drift is in the Lincoln Sea above Nares Strait and westward along the coast of the CAA.
However why would special conditions there hold up under conditions of massive open water elsewhere? We might see instead rapid collapse of the last hold-out areas.
Posted by: A-Team | July 07, 2013 at 23:48
Why do you find that picture so unlikely? At the point when we have a fully seasonal Arctic ice cover, I fully expect the last bits of ice each year to be somewhere around the entrance of the Fram. This is no more than saying that a nearly-empty sink is likely to have water near the plughole.
Posted by: Pjie2 | July 08, 2013 at 01:00
The calculation was intended to determine the year of September sea ice disappearance using that month's Piomas, which is to say on declining thickness of historic MYI grid cells.
There is no provision for knock-on effects of years of nearly all first year ice, nor for net motion of MYI ice being modelled as originating in a refugium/thickening area to the west.
As of late June of this year, the Fram has become almost entirely empty, due to some combination of less export and faster melting in warmer waters of the North Atlantic.
We may see rather drastic changes in both vertical and horizontal oceanic circulation before quite arriving at 'fully seasonal Arctic ice cover'. If well-mixed, the heat content of the deeper waters would overwhelm surface ice -- only a metastable equilibrium from stratified density layers allows it at all now.
So it would seem future Arctic wind and current patterns have to be tackled before discussing persistence modes of seasonal ice, and indeed before getting on to climate change in the overall northern hemisphere.
Posted by: A-Team | July 08, 2013 at 01:49
the ice is breaking up in situ in Nares Strait.
the north west passage will soon follow.
How it compares with previous years I do not know but it is clear to me that ice passing through Fram strait is melting very fast.
if you look at MASIE there have been numerous upticks during June and the first days of July.
20,000 up and then gone within 24-48 hours.
that suggests to me that no matter what the theoretical thickness of that ice is the reality is that it is thin. same is happening in the Barents and Kara seas.
Meanwhile that low concentration ice in the central Arctic is not getting any better. going to take a major weather event to compact that lot.
my money is on either a huge polnya or an ice ege close to the North pole come September.
Thoughts of recovery are wishful thinking. there is no recovery.
Posted by: philiponfire | July 08, 2013 at 02:46
I'm finally getting my MODIS swath pipeline sorted out as the melt is getting more exciting. Here's about 30 hours of swaths from covering the Arctic for Terra (Aqua has equal coverage on different passes). This is about 7 GB of swath data I downloaded, covering 00:00 UT July 6th - 07:00 UT July 7. The original resolution was 500 m/pix, and the animation does look beautiful at 4000 pixels wide. Adjacent swath images are 5 minutes apart in time.
You can see that a small area around the north pole is covered on every pass, while areas further from the pole are still covered quite frequently compared with the 2x/day or so at the equator.
Here is a subview at 500m resolution. The pole is marked, along with image timestamp. This isn't the most interesting part of the melt yet, but do note that the view is only 200 km wide, so that little rotating bunch of floes in the upper center is only 100 km from the pole.
I can extract similar animations without much trouble, but the amount of upfront data download has remained cumbersome.
Obviously NASA has done calibration beyond level 1B of the swath data to correct for solar angle, extinction, etc., which is why this mosaic will never look as pretty as earthview's. But I can get high temporal resolution, and use various cloud-free combinations more flexibly. I also have available the full range of wavelength bands into deep IR, which could give more useful cloud removal than yet seen (as well as better low-light images).
Posted by: Dan P. | July 08, 2013 at 08:31
A-team, what awesome work you are delivering here. Compliments !
Regarding your July 07, 2013 at 17:29 post (parabolic intensification of the palette) to show "might approximate how the ice will look in future weeks", there is physical evidence for that animation.
After the summer solstice (June 21), until sun-set in September, the Arctic insolation (on the ice) is something like 1.3 GJoule on average per square meter (through the clouds and everything). That is enough heat to melt some 3.8 meters of ice.
If we assume (conservatively) that the difference in albedo between open water and melting snow is about 0.5, then still there is enough heat to melt about 2 meters of ice for every open square meter of water in the Central Arctic.
Since typical thickness of ice in the area with the holes in the Arctic Basin is something like 1.5 meters (check bouy 2012J or 2013A), a quick "back of the envelope" calculation shows that 75 % ice concentration now will grow to 50 % at the end of the season, and 50 % ice concentration now will pretty much be open water at the end of August. And that is with average weather and no wind, nor certainly no GAC this year.
I'm not sure though if the area of 'holes' in the Central Basin, and the anticipated ice loss for the rest of the season, will compensate for the slower melt in the 'outer' areas and the Beaufort specifically.
Posted by: Rob Dekker | July 08, 2013 at 09:48
Nares Strait / Kane Basin / Kennedy Channel.
The collapse of the sea ice in the area is now underway:
https://forum.arctic-sea-ice.net/index.php/topic,176.0.html
Posted by: Espen Olsen | July 08, 2013 at 12:52
DanP, that is fantastic than you have been able to get a grip on this. A cloud-free view culled from a single day would be a great leap forward. And with most of the satellite's channels completely lost from public view, we have no idea what it is seeing at longer wavelengths.
I made a start on something similar for the Jaxa satellite GCOM-W1 program. It provides two views a day, ascending and descending orbit, in two polarizations, horizontal and vertical, at 7 wavelengths for 28 images per day. Some mysteries here: does 7 Ghz offer anything new over 6 Ghz, why the 89Ghz A and B antennas? Again, onerous downloads, hard-to-fix palettes.
The slide show below for 04 Jul 13 is arranged by polarization in decreasing frequency alternating descending and ascending views. There are various interpretive issues around moving clouds, time of day, snow condition etc but if we can get past that, judging by correlation with other types of imagery, there seems to be valuable information on the state of the ice.
In effect, having all these wavelengths provides the time-dependent emission spectrum for the entire ice pack. That's easy enough to do at representative pixels and this may be key to overall artifact removal and ice interpretation.
Posted by: A-Team | July 08, 2013 at 16:02