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Messages - Rob Dekker

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1
The rest / Re: Russiagate
« on: August 20, 2017, 06:01:44 AM »
Zeug Gezeugt said August 14, 2017, 10:54:09 PM
This latest from Rob Parry engages with precisely your concerns re Trump and the DPRK - https://consortiumnews.com/2017/08/12/russia-gates-fatally-flawed-logic/

To which Jim replied :
I don't pretend to speak for others, but I have to tell you that if you could maybe quote from a more credible, less pro-Putin, rabidly anti-Hillary source than Parry, we might be inclined to listen. In the meantime, I really have no choice but to ignore such baseless nonsense...

Then Terry comes in with :
This latest from Rob Parry engages with precisely your concerns re Trump and the DPRK - https://consortiumnews.com/2017/08/12/russia-gates-fatally-flawed-logic/
Thanks for the great link!
And the comments were as intelligent as any I've found....

Clearly, different opinions about the same article.
I've read Parry's articles on MH17, and they are terrible.
There is a double edged sword in every sentence.
Let's just take the first sentence of the article you both refer to :
By pushing the Russia-gate “scandal” and neutering President Trump’s ability to conduct diplomacy, Democrats and Congress have encouraged his war-making side on North Korea, writes Robert Parry.

Even on that single sentence, it's hard to know where to start weeding the facts from the opinions.

Parry does that in ALL of his sentences in ALL of his articles.

His articles are just so pro-Putin and so against the truth and ignoring so much evidence that I stopped reading Parry a long time ago.

2
Arctic sea ice / Re: Northern Sea Route thread
« on: August 20, 2017, 03:56:51 AM »
Canada could, in theory, claim the Northwest Passage an internal waterway. Or, if shot down on that claim, some portions are <12 miles in width, thus giving Oh! Canada a second jurisdictional claim.

In theory, Canada can claim that (certain routes) of the Northwest Passage are "internal waters".
They would need to file that claim, with supporting evidence, and present it to the UN, which will then make a ruling. Canada has not done that yet, so existing rules apply.

If Canada can identify a route that is less than 24 miles wide (2*12 miles), then YES, they can claim that route as internal waters even under existing law. And they could even charge a fee for passing if they want to. But for any route wider than 24 miles, current laws of the sea (UNCLOS) applies, and these passages would be free for all to pass.

3
Arctic sea ice / Re: Northern Sea Route thread
« on: August 19, 2017, 10:06:24 AM »

.... a fee if search-and-rescue is needed.

The written and unwritten Law of The Sea requires assistance to be given to anyone in distress on the sea without counting the cost.

Where exactly in UNCLOS do you see that requirement (especially the part about "without counting the cost") ?

4
Arctic sea ice / Re: Northern Sea Route thread
« on: August 19, 2017, 09:31:52 AM »
I don't believe that any 'Communist States' had any stake in the Arctic, even back in 1994.

Can you elaborate ? You think Russia didn't want an Exclusive Economic Zone 200 miles off their coast, or did you mean to say that Russia was not a Communist State in 1994 ?

Canada has been concerned with the pollution of what she considers to be her northern waterways, while the US has always maintained that these are open to all.


ALL waterways, especially the ones more than 12 miles of the coast are open to all.
That's the whole idea behind UNCLOS, and it counts for the NW passage and the Northern Sea Route as well :
http://www.un.org/depts/los/convention_agreements/texts/unclos/unclos_e.pdf

5
Arctic sea ice / Re: Northern Sea Route thread
« on: August 18, 2017, 08:02:36 AM »
Thank you sidd for clarifying the US position w.r.t. UNCLOS.
From the Wiki page
https://en.wikipedia.org/wiki/United_States_and_the_United_Nations_Convention_on_the_Law_of_the_Sea
we read :
The United States objected to Part XI of the Convention on several grounds, arguing that the treaty was unfavorable to American economic and security interests. The U.S. claimed that the provisions of the treaty were not free-market friendly and were designed to favor the economic systems of the Communist states.

Which kind of makes sense, when we look at the picture that Pavel posted.
About 1/3rd of the Arctic now falls within the Exclusive Economic Zone of Russia.



I find it rather ironic that since UNCLOS was signed in 1994, that the US has obliged by its rules (after all they signed the Agreement of Implementation) even though they did not sign the Convention itself, but Russia seems to be the only state that is still violating UNCLOS law even though they DID sign.

Now, don't get me wrong. The Arctic is a very large place, and the Northern Sea Route is long and still has pockets of ice even in August and September. So it's fair if Russia would charge a fee if ice-breaker assistance is needed and a fee if search-and-rescue is needed. But requiring a permit and fee for anyone sailing its international waters (beyond 12 miles from the coast) clearly does violate UNCLOS.

Incidentally, that permit process and the fees make the Northern Sea Route less attractive for business, which may help in keeping the NSR a bit less popular as a reliable sea route. Other routes, including the NW passage may be more cost effective in the end.

6
Arctic sea ice / Re: The 2017 melting season
« on: August 18, 2017, 05:49:55 AM »
The lower animation below looks at this puzzling persistent polynya along the 120th meridian north of 80º (yellow star). It first shows up around June 23rd on the UH 3k concentration map and has persisted since, drifting south along with the ice pack.

The WorldView overlay (snatched from @zlabe for Aug 16th) shows quite a large feature consisting of open water with some scattered floes. The GEBCO bathymetry overlay shows that the polynya formed and resides over water some 3200 m deep; there is no association with continental shelf or Atlantic water along the break, nor with Lomonosov Ridge.

I would say further it has nothing to do mid-ocean tides nor with the Gakkel Ridge divergent plate spreading center nor warm water upwelling from its weak hydrothermal vents and sporadic pyroclastic volcanism far to the southwest.

Perhaps the polynya formed by happenstantial pack shifts or local cyclonic winds and is maintained by rigid motion of the surrounding ice. However that isn't plausible if a polynya forms in the same spot in multiple recent years. That could get murky depending on the extent of other ice loss in the region; Aug 2016 was too cloudy at this lat,lon to form me to an opinion.

Hycom flashes some low thickness pink at the approximate location for the first 11 days of August but it is not entirely convincing as the direction of movement seems slightly off. The polynya is not apparent on Piomas, though wip's mid-July animation seems the latest.


Ah. The Laptev triangle.
Indeed this is a puzzling feature.
Prior years it showed up as the 'Laptev bite' pretty much in the same place. About 120E/80N.

Thanks A-team for ruling out a lot of different possible causes for this feature. Your arguments make sense.

I would like to propose one theory that anyone may shoot down with any reasonable argument :
The feature shows up in the Laptev side of the Eurasian basin. That is where deep (under the halocline) warm Atlantic water current makes a U-turn :



The Laptev Triangle shows up in the center of that U-turn.
So here is my theory : Coriolis forces push matter to the right in the Northern Hemisphere, but also (less known) UP if it moves East and DOWN if it moves west.
https://en.wikipedia.org/wiki/Coriolis_force

So could it be that while that Atlantic water goes through its U-turn (moving East), that it gets pushed up a little bit ?
If so, some of that warm Atlantic water may end up above the halocline and cause more bottom-melt than in other places, which leads to a polynia later in the melting season (now).

7
Arctic sea ice / Re: Northern Sea Route thread
« on: August 17, 2017, 09:31:42 AM »
Territory generally now includes water over continental shelves. Most countries recognize this but notably the US does not because they insist they can send their warships to within 12 miles of any country.


No ghoti.
The Laws of the Sea are very clear. There are no claims of 'territory' or 'sovereignty' beyond 12 miles.
http://www.un.org/depts/los/convention_agreements/texts/unclos/unclos_e.pdf

It kind of makes sense too : In the olden days, pirates or rogue states claimed a certain part of the sea their own, and demanded one paid a fee to pass.

Luckily we have the UN now, and the Laws of the Sea, signed by all major states including the US.

As far as I know, Russia appears to be the only state to charge a fee if you want to pass the international waters along their coast (along the Northern Sea Route), and shoots at you if you don't...

8
Arctic sea ice / Re: Northern Sea Route thread
« on: August 16, 2017, 09:25:34 AM »
Terry said :
The Law of the Sea says it's Canadian

No it doesn't.
Territorial waters or a territorial sea, as defined by the 1982 United Nations Convention on the Law of the Sea, is a belt of coastal waters extending at most 12 nautical miles (22.2 km; 13.8 mi) from the baseline (usually the mean low-water mark) of a coastal state.

Anything outside this 12 miles range is 'international waters' where "no State may validly purport to subject any part of them to its sovereignty".

This is something neither Canada (who claims the entire NWP is theirs but doesn't act if you cross it) nor Russia (charges a fee and shoots at you if you want to cross the Northern Sea Route without their permission, even if you are more than 12 miles from the coast) disputes.

See the contradictions with the Law of the Sea from both Canada and Russia in this ?
And how they differ ?

9
Arctic sea ice / Re: Northern Sea Route thread
« on: August 16, 2017, 09:15:56 AM »
Adam Ash. No.
Transporting coal via the Northern Sea Route is like adding insult to injury.

10
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: August 14, 2017, 08:41:17 AM »
Neven, your various measures of ice concentration are interesting, but I'm not sure if I understand the reasoning. For example :
I figured that if I used SIA at a low resolution, grid cells will be big and thus melt ponds and leads will have a larger impact on the numbers.

That is not necessarily the case. In fact, SIA numbers should be rather insensitive to resolution.
After all, if ice concentration is, say 30% over some area A of the Arctic, then regardless of the grid cell size, SIA will be calculated as 0.3*A.

'Extent' on the other hand DOES depend on the grid cell size. Especially on the ice edge.
So your NAPAE graph (NSIDC SIA / UH SIE) will be similar to (UH SIA / UH SIE) which is the 'blue' lines in Wipneus' ice concentration / compactness graph :

And indeed these 'blue' lines (with the black line being 2017) show concentration that is not as high as NSIDC's compactness graph.

The only thing I think you can conclude from that is that currently, there are fewer 'wide' (3km-25km) polynia than there were in prior years.

11
Permafrost / Re: Negative Feedback of Positive Snowfall Anomalies
« on: August 14, 2017, 07:36:59 AM »
Regarding land snow cover, and its potential as a 'negative' feedback, let us get the facts strait :
For starters, I encourage everyone to read this article by tamino :

https://tamino.wordpress.com/2012/10/05/snow-2/

It investigates the effect of snow cover over the past 3 decades, and it concludes that it is definitively a 'positive' feedback. Just look at the snow cover loss over the months :


which suggests that land snow cover is lost in summer much more than it is gained in winter.

Or read this follow-up article :
https://tamino.wordpress.com/2012/10/08/snowice-by-request/

which asserts :

The net change estimated as the difference of the beginning and ending values of the trend line is about 880 TW. If spread over the entire surface of the earth, and if the difference in TOA albedo between snow/ice-covered and uncovered regions is 0.2, this accounts for a total climate forcing of about 0.34 W/m^2.

There you have it. Ice and snow loss imposes a 'positive' feedback on the planet's temperature, to the amount of some 0.34 W/m^2.


12
Permafrost / Re: Negative Feedback of Positive Snowfall Anomalies
« on: August 14, 2017, 07:24:49 AM »
VAK, one thing is bothering me with what you wrote.
Once there are no sea ice floes left at the Central Arctic Basin, the sea ice growth no longer advances from the North Pole to the South (towards the ocean's perimeter). Now the re-freeze must progress inversely from the perimeter in the south towards the North Pole at the centre of the ocean.

Do we know this for sure? Surely at a low enough temps the sea surface will freeze. Admittedly open water impede the drop in temps, but still what you wrote seems more like an assumption rather than a substantiated claim.
The fact that sea ice typically grows from other sea ice doesn't mean it can't do that spontaneously as well.


I agree, oren. I find it doubtful that after a Blue Ocean Event that ice would need to grow from the perimeter. The insolation difference between 90 deg North and perimeter at 60 North in September is a whopping 200 W/m^2 :



That kind of difference in insolation makes it very likely that ice (post September) will simply start from the highest latitude and grow towards lower latitude.

13
Arctic sea ice / Re: The 2017 melting season
« on: August 13, 2017, 09:23:04 AM »
The lower-bound for September average from the Slater's forecast model was 4.5 M km^2, which occurred in the first half of  September.


14
Arctic sea ice / Re: The 2017 melting season
« on: August 13, 2017, 08:26:38 AM »
Andrew Slater's model projects 5.39 M km^2 for Oct 1.
So I guess that's the upper bound for the September average.


15
Arctic sea ice / Re: What the Buoys are telling
« on: August 13, 2017, 07:37:09 AM »
At this point, I'd like to point out a remarkable consistency between IMB (Ice Mass Balance) buoy 2017A and co-located WARM buoy 6 when it comes to ice bottom melt.

IMB buoy 2017A shows this melting profile :

Note that over July, that amounts to about 2 cm/day of bottom melt.

WARM buoy 6 records this profile of in-ice and under-ice PAR irradiance :



which suggests PAR irradiance (light between 400 nm and 700 nm) was some 30 W/m^2 over July.
We know that sunlight holds some 43% of its energy between 400 and 700 nm, so we can reasonably expect that some 30 * 1/0.43=70 W/m^2 of sunlight made it through the ice in July.
70 W/m^2 is enough heat to melt 2 cm/day of ice, very consistent with the 2 cm/day we see recorded by 2017A. Other WARM buoys (such a WARM 3) suggest that this level of irradiance is common, and lasts July through Aug.

This is telling although not quite unexpected. It suggests that light that makes it through the ice is THE main source of bottom melt in the Arctic sea ice pack.

It also tells a lesson, since this should be happening all through the Arctic : Even without external influence, simply the Arctic light that shines through the ice can account for 2 cm/day bottom melt through July and August. That's 120 cm right there. Add 30 cm of top melt and we can conclude that any ice that is 1.5 meter of ice thickness or less at the start of the melting season is at risk of melting out in-situ.

16
Arctic sea ice / Re: The 2017 melting season
« on: August 11, 2017, 09:42:50 AM »
That's very interesting Rob.  I guess what is more interesting is that the cold caused by that significant snow didn't have a bigger effect.

To me it looks like the whole pack is at risk of one significant storm sweeping in through the Beaufort, Chuchki and ESS and overwhelming anything retained by the snow anomaly.

Quite right, Neil.
It looks like the snow anomaly cooled things down, but not enough to prevent major reduction of Arctic sea ice. While in other years it would. The only fair reason I can come up with is that the ice this year is really thinner than in prior years, which adds credibility to PIOMAS' ice thickness estimates.

17
Arctic sea ice / Re: PIOMAS vs CryoSat
« on: August 11, 2017, 07:02:35 AM »
A sample of 40-60 measurements per pixel indeed would imply a large uncertainty (SQRT(1/N)=2.5%).
However, spread out over the hundreds or thousand pixels in the outer Arctic Basin, the confidence interval of the determination of ice thickness should be pretty tight (much less than 0.25%).

18
Arctic sea ice / Re: What the Buoys are telling
« on: August 11, 2017, 06:47:40 AM »
Just when you think you have a constructive discussion going on about a genuinely interesting subject, there is always Ktonine to slap you down.

19
Arctic sea ice / Re: The 2017 melting season
« on: August 11, 2017, 06:19:05 AM »
DavidR said on the ASIB :
According to the NOAA-ESRL measurements 2017 has been colder than 2013 and 2014 in both the Arctic and the high Arctic (80N+) over most of the May - Jul period and on average.

Thanks David, for pointing this out !
As for the where this 'cold' resided during this summer, here is the NOAA spacial plot (May-July, 60-90deg) for 925 mb temperature.

Note that the cold was most intense around the Laptev shoreline, incidentally the same location where the land snow lasted longest, and created that significant land snow anomaly this June :
http://climate.rutgers.edu/snowcover/chart_anom.php?ui_set=1&ui_region=nhland&ui_month=6

20
Arctic sea ice / Re: What the Buoys are telling
« on: August 11, 2017, 05:06:51 AM »
One more question, Victoria :

In the same image as the graphs for irradiance (see above) there is a graph for something labeled as "DOM(?) fluorescence" in ppb (parts per billion).

What is that exactly, and which sensor records it ?

21
Arctic sea ice / Re: What the Buoys are telling
« on: August 11, 2017, 04:08:20 AM »
Thank you Victoria, for your explanation of the irradiance sensors, and the WARM buoy in general.

I have a few more comments and questions :

3) To get from sensors to PAR in W/m^2, which algorithm did you use? And would it be hard to adjust the algorithm so that it produces an estimate of full-spectrum irradiance?


The sensor inside the PAR channel has a filter in front of it that lets through all light between 400 and 700 nm. This means that we can't get a full spectrum from this kind of instrument.


That is of course true, but the PAR sensor has a 400 nm - 700 nm filter and you calculate the 'energy' flow through that in W/m^2. Since we know that 400nm - 700nm contains about 43% of the energy of the full spectrum of normal sunlight, isn't it OK to just multiply your PAR irradiance [W/m^2] by 1/0.43=2.3 to obtain at least a first-order 'full-spectrum' energy flux ?

Regarding the WARM 3 irradiance data, this remark from you was an eye-opener :

As the ice melts the buoy slips through the hole, with all the sensors becoming 3 m deeper in the water.


Brilliant ! That explains the sudden drop-off in irradiance in mid-July of both in-ice and under-ice sensors ! The sensors all slipped 3 meters down, as is also witnessed by your pressure sensors :

It's good to know that is how the WARM buoys are constructed, since WARM 6 is about to entertain the same maneuver, right ?
 
Now the only thing odd about the WARM 3 data is that extremely high irradiance for the in-ice sensors during June. That (irradiance up to 350 W/m^2) is very high when compared to WARM 6, and its very high when compared to the under-ice irradiance (of less than 10 W/m^2).

Overall, with these WARM buoys you got yourself a beautiful set of cool instruments, Victoria. Thank you for sharing the data with us.

22
Arctic sea ice / Re: PIOMAS vs CryoSat
« on: August 10, 2017, 09:34:50 AM »
The comparison is between PIOMAS hiday daily gridded Effective Sea Ice Thickness and the CPOM 2 day, 1 km NRT product.

The difference is calculated by subtracting the AWI value from the PIOMAS value.

Thanks Michael !
This still suggests that PIOMAS overestimates ice in the outer areas of the Basin w.r.t. Cryosat2.
This when that ice melts, PIOMAS records a large volume loss, explaining the fast drop in June in volume. Then once melting goes a bit deeper into the CAB, PIOMAS underestimate ice thickness there, which explains the 'rebound' we see in Wipneus' volume anomaly graph for the years that extent goes low :
https://sites.google.com/site/arctischepinguin/home/piomas

Result : Observations suggest that PIOMAS underestimates thickness of ice in the boundary of the Arctic Basin, and possibly overestimates ice thickness in the CAB.

23
Arctic sea ice / Re: The 2017 melting season
« on: August 10, 2017, 09:02:29 AM »
The story this year has been low volume.  The warm winter was not able to restore the ice lost last summer.  Therefore the relatively few melt ponds in June and the relatively high snow cover weren't able to make up for the weak and mobile ice.

That's exactly it. We've seen weather similar to 2013 and 2014, the rebound years that followed 2012 (someone over on the ASIB just wrote that "According to the NOAA-ESRL measurements 2017 has been colder than 2013 and 2014 in both the Arctic and the high Arctic (80N+) over most of the May - Jul period and on average"), but 2017 just keeps digging low.

This is perhaps the most educative melting season I've seen....

I agree.
The parameters that I used (land snow cover, ice concentration and ice area) were all pointing to a year similar to 2013/2014. Yet 2017 keeps on going down with the record holders 2007/2012.

I still have some hope (with 2017 being cool, but having low 'extent') that the minimum will come early this year, simply because the ice edge is closer to the NP. So maybe a rebound in the latter part of September will still let 2017 finish quite high.
But that is just wishful thinking at this point.

24
Arctic sea ice / Re: What the Buoys are telling
« on: August 10, 2017, 08:48:19 AM »
Oops. I see that Jim already replied on ITP95.

25
Arctic sea ice / Re: What the Buoys are telling
« on: August 10, 2017, 08:42:34 AM »
ITP95 is on its way out of the Arctic and into the Atlantic



As all the prior buoys that followed that path, the halocline starts to disappear and more salty Atlantic water takes its place.

26
Arctic sea ice / Re: What the Buoys are telling
« on: August 10, 2017, 07:19:07 AM »
Thank you Victoria, for checking in with the ASIF !

I find your WARM buoys extremely interesting and useful.
Since they have temperature and salinity sensors down the tether, they mimic the information normally obtained by ITP buoys.
And since the have in-ice and under-ice irradiance sensors, they provide and indirect measurement of bottom-melt, thus providing the information normally obtained by IMBs (like 2017A).

Thus, your WARM buoys are like two buoys at once, as long as we can obtain full-spectrum under-ice measurements (not just PAR). And it is in that regard that I have some questions :

You mentioned in an email to Jim :
However, I do have some sensors on the string that are measuring irradiance at three wavelengths, 412, 443 and 555 as well as PAR, depths, 5, 10 and 20 m. This does enable me to get an idea of the spread of the light through the spectrum, and I have used a modeled surface spectrum, propagated through sea ice (using Bonnie Light’s coefficients) and then normalized to my data to estimate spectral irradiance under the ice.


Couple of questions on that, with the purpose of finding out how we can determine full-spectrum irradiance from the sensors on your buoys :

1) Do your WARM buoys have 4 different sensors (412, 443, 555 nm and a separate PAR sensor) ? Or just 3 sensors (412, 443, 555 nm) and you calculate PAR from that ?

2) If PAR irradiance data is obtained from a separate sensor, then what is the wavelength sensitivity distribution of that sensor ?

3) To get from sensors to PAR in W/m^2, which algorithm did you use ? And would it be hard to adjust the algorithm so that it produces an estimate of full-spectrum irradiance ?

4) I've been looking for the irradiance raw data in your "level 1 data" in the WARM 6 data page
http://psc.apl.washington.edu/UpTempO/BuoyInfo.php?cbuoy=9080&bname1=UpTempO%202017
However, that "level 1 data" does not include data from the irradiance sensors. Could you add that ?

Besides these questions about the irradiance sensors, I am a bit puzzled by the irradiance data from some of the WARM buoys. For example, the WARM 3 data (from 2015) :



Here we see that during June, and part of July, in-ice PAR is very large (some 200 W/m^2 on average) but under-ice PAR is very small (mostly less than 10 W/m^2).
Starting from the second half of July things return to normal with in-ice PAR at some 50 W/m^2 and under-ice PAR is some 40 W/m^2.

What happened there in June ? Is there a logical explanation for the huge difference between in-ice and under-ice PAR ?

27
Arctic sea ice / Re: The 2017 melting season
« on: August 08, 2017, 10:47:52 AM »
The one below (underneath as-is) isn't striving so much to recovered masked concentration values as it is seeking persistent feature visualization and their motion. The upper ten percent of ice concentrations are not resolvable visually so the whites have been replaced by a tan color.

That "tan color" feature is very noisy, and certainly not "persistent". Since it is related to the upper ten percent, which is not indicative of ice melt, I'd suggest you replace it with the immediately below 90% bracket which is white. That should stabilize the image and be more gentle on the eyes.

28
Arctic sea ice / Re: PIOMAS vs CryoSat
« on: August 08, 2017, 10:40:16 AM »
Michael, A-Team and GreatDying2 :
Is it fair to say that from this animation of PIOMAS-AWI :



that at least w.r.t. Cryosat2 that PIOMAS overestimates thickness of the thinner ice on the boundaries of the Arctic basin, and possibly underestimates ice in the CAB ?

If so, it would explain some of the features in Wipneus' PIOMAS volume anomaly graph :
https://sites.google.com/site/arctischepinguin/home/piomas
and specifically the fast drop in June and the re-bound in July of the years that go low...

29
Arctic sea ice / Re: IJIS
« on: August 08, 2017, 10:13:56 AM »
Hi Espen,
I don't want to rock the boat much, since this is not a big deal.
But your greeting "Have a ice day!" should really be "Have an ice day!", not just for English grammar reasons, but also because it enforces the pun.

30
Arctic sea ice / Re: The 2017 melting season
« on: August 07, 2017, 10:14:41 AM »
The attached 2 animations may help you get a better sense of how the melt season has proceeded over the last 2 weeks. The first shows the original Bremen NIC concentration images (cropped). The second shows a filtered version, where each pixel is set to the latest concentration less than 90% (i.e. not purple) over 5 days (current day plus preceding 4 days).

Thank you greatdying2, that is a very useful animation. You can really see the low concentration ice proceed deeper into the CAB, and there is not as much noise as the original AMSR2 images.
One note : You mention ''latest concentration", but I assume you mean "lowest concentration", is that right ?
And one question : You chose 5 days for your filter while previously you chose 3 days (the LAMB).
What made you change that filter period ?

31
Arctic sea ice / Re: What the Buoys are telling
« on: August 07, 2017, 09:00:47 AM »
Super cool!

One interesting thing is that although solar irradiance peaked on June 20, there has been -- as Rob points out -- no obvious reduction in water column or in-ice PAR irradiance since then (and perhaps the opposite).


Indeed, in-ice and under-ice irradiance over July appears to be fairly constant.
I pulled up anther WARM buoy (W-3), this one from 2015, which shows this profile :



That suggests that irradiance under ice is highest, and fairly constant, during July and August, then tapers off quickly in September. That kind of makes sense : As the ice is melting it become more transparent, and thus lets more light through, which compensates for the reducing insolation above the ice during July and August.

32
Arctic sea ice / Re: What the Buoys are telling
« on: August 07, 2017, 08:51:54 AM »
Thanks Jim !

33
Arctic sea ice / Re: What the Buoys are telling
« on: August 06, 2017, 04:32:54 AM »
Note that the irradiance measured is "PAR". That is Photosynthetically Active Radiation (PAR) or just the wavelengths absorbed by chlorophyll. The total irradiance will be significantly higher since it also includes infrared, green, and ultraviolet. Also the chlorophyll they are measuring is absorbing PAR before it reaches the sensors. So energy input is actually higher than the 30ish W/m2

Thanks gothi ! I did not realize that.
I've been looking for a multiplier to relate "PAR irradiance" to full spectrum irradiance.
I found that PAR is is typically defined as the 400 nm to 700 nm spectrum, which is where about 50% of the energy resides :
https://en.wikipedia.org/wiki/Photosynthetic_efficiency
That would suggest a 2x multiplier and potentially 2 cm/day of bottom melt.

However, there is a part within that spectrum (green) where plants reflect the light, so when you loo k at the active radiation, PAR may be just 33% of full spectrum radiation :
https://en.wikipedia.org/wiki/Photosynthetically_active_radiation
Which would suggest a 3x multiplier and potentially 3 cm/day of bottom melt.

Ultimately the multiplier depends on how exactly the sensors' raw data is translated to PAR irradiance.
So, Jim, I have a favor to ask :
Since you are already in contact with Victoria Hill, could you ask her if there is a simple multiplier to translate PAR irradiance to full spectrum irradiance in these WARM buoy data ?
Even a ballpark number would help in determining bottom melt potential for light that shines through the ice.

Also, please ask her what we (as a community) could do to support deploying more of these WARM buoys. After all, the information these buoys return is very important in determining the one unknown that can not be measured directly otherwise, yet still ultimately important to the fate of Arctic sea ice : bottom melt of Arctic sea ice...

34
Arctic sea ice / Re: What the Buoys are telling
« on: August 05, 2017, 09:10:18 AM »
Thanks for the discussion on 2017A's top-melt profile and how it relates to the images sent by the WARM buoy at the same location. I tend to agree with many of you that we probably are over-thinking it. After all, many buoys melt a hole right around the stem, which drains any melt water to sea level, and thus a melting pond will not form around the buoy itself.
Also, it is clear that no matter the process (top or bottom melt) the ice at that location appears to be very thin right now.

For example, the co-located WARM buoy 6 (that holds the camera that documented 2017A) records being in open water. At least, somebody wrote "open water!" on the Aug 2 tag in Jim's tracker site :
https://sites.wp.odu.edu/BORG/current-projects/warm-buoy-maps/
Sidekick#2, WB#6 Aug 02 2017, 77.276106, -145.855897 - open water!


with this image of the buoy seen from below :


I looked into that WARM buoy a bit more, and found out that is actually a really COOL (pun intended) instrument !

I have not seen much reporting about WARM buoys on the ASIF, but essentially, it is a buoy with a 20 or 50 meter tether, with various sensors along the line. Here is a good overview of the system :
https://sites.wp.odu.edu/BORG/current-projects/temperature-and-irradiance-measurements-in-the-arctic/

One of the sensors is a camera, mounted 20 meters deep, looking upward, and that is the one that is producing the images at this time (like the one above from Aug 2). Jim, you mentioned that the 'above surface' camera is looking at the sky now, but how do you know that ?

But the thing that makes the WARM buoys REALLY cool (in my opinion) is that they have "irradiance" sensors at certain depths. These sensors record how much sunlight makes it through the ice. Here is the data for this particular WARM buoy :



Full data for this buoy is here :
http://psc.apl.washington.edu/UpTempO/BuoyInfo.php?cbuoy=9080&bname1=UpTempO%202017

Note that very little sunlight makes it through the ice before June. That is when there is still snow cover on the ice. But after that, irradiance moves up quickly, and during July we see 30-40 W/m^2 makes it through the ice, and we see that most of that heat gets absorbed in the top 20 meters of water below the ice. That is still above the halocline, which means that most of that heat will make it it causing bottom melt. And remember that 35 W/m^2 will cause about 1 cm/day of bottom melt.
This (30-40 W/m^2 shining through the ice) appears to be typical for July, when we look at other WARM buoy data.

So here we see a quantification of a main cause of Arctic sea ice bottom melt.

That's pretty awesome, no ?

35
Arctic sea ice / Re: The 2017 melting season
« on: August 04, 2017, 10:29:14 AM »
Here is the 3-day LAMB (LAgging Minimum Bremen) map for 4 weeks ending Aug. 2nd:

Very nice work !
Your 3-day LAMB is definitely more 'consistent' than the unfiltered AMSR images.
Also interesting that (in this 4 week animation) the ice North of the Chukchi disappears much faster than the ice North of the ESS or the Beaufort.
Suspect is that (persistent) cyclone that drives the ice towards the CAB from the Chukchi.
 

36
Arctic sea ice / Re: What the Buoys are telling
« on: August 04, 2017, 10:18:01 AM »
OK. This top-melt graph shows a gradual loss of some 40 cm of ice after some 20 cm of snow. That is 60 cm of loss of 'altitude' from the top.

I cannot reconcile that with the animation by oren over the past month, since that shows no loss of altitude, but instead an alternating surface of snow and water.

37
Arctic sea ice / Re: What the Buoys are telling
« on: August 04, 2017, 09:06:39 AM »
Thanks oren for that animation !
It appears to show that that location went through several cycles of thaw, refreeze and snow fall over the past 4 weeks.

Jim's 2017A temperature profile appears to sustain that : there are several dates with below freezing temperatures at the first thermistors.

However, the 2017A sounder data seems to suggest a nice gradual top-melt, without any refreeze cycles:



Interesting paradox, no ?

38
Arctic sea ice / Re: The 2017 melting season
« on: August 03, 2017, 10:03:36 AM »
I have not looked at it directly but believe that there may be some significant contribution from West Greenland and Hudson Bay as well.  The SIE values are northern hemisphere and include all visible sea ice.

Fair point, Jai.
Wipneus noted in the "sea ice area and extent" thread, regarding the double-century drop :
extent drop is big and is mainly within the Basin. Ice in the Beaufort, Chukchi, CAB border region is getting a beating from a storm,

So it looks like the main action is indeed from the CAB and surrounding seas.

39
Arctic sea ice / Re: The 2017 melting season
« on: August 03, 2017, 09:59:29 AM »
What I've done is to convert each pixel to a concentration value using the colours provided in the key, take the minimum concentration, then map it back to the colour.

Sometimes clouds create virtual 'low' concentration pixels, so you may actually be amplifying cloud effects in your program. Like that patch SW of the NP in your latest image.

That said, I'm surprised that your three-day algorithm finds most of the low concentration ice in the ice margin, where we would expect it.

Nice work !

40
Arctic sea ice / Re: What the Buoys are telling
« on: August 03, 2017, 09:08:05 AM »
In that image from the WARM buoy for July 18
https://sites.wp.odu.edu/BORG/wp-content/uploads/sites/57/2017/07/001022276_00484.jpg

Is that the 2017A 'sounder' that we see there on the left ?
If so, note that it is standing in snow. Not in water.
Does that make sense, given the temp profile of 2017A ?

41
Arctic sea ice / Re: The 2017 melting season
« on: August 03, 2017, 09:03:07 AM »
A few days ago, I suggested that since ice concentration was running very high (2013/2014 levels),  that 'extent' was about to 'stall' since typically 'area' is a better indicator of actual ice melt, and 'area' has been running quite high for some time.

Only to get slapped around the ears with two century breaks in 'area' and a double century break in 'extent', while the only thing of significance that could have caused that is a mild storm on the Pacific side. One that 'normally' should actually cool down things, and cause some dispersion.

The only reasonable explanation for these century breaks seems to be that (as many of us have pointed out before) that the ice in 2017 is simply thinner and thus more sensitive than in prior years, just like PIOMAS told us all along. It's just that the effect of that thinner ice is really starting to show up now at the end of the melting season.

High ice concentration (and 'area') were at the core of my 'high' projection, and I'm starting to feel a bit concerned now that we may see a lot more ice disappear rather than preserved before the end of the season....

42
Arctic sea ice / Re: 2017 sea ice area and extent data
« on: August 03, 2017, 08:50:50 AM »
A few days ago, on the "melting" thread I suggested that since ice concentration was running very high (2013/2014 levels), and I suggested that 'extent' was about to 'stall' since typically 'area' is a better indicator of actual ice melt, and 'area' has been running quite high for some time.

Only to get slapped around the ears with two century breaks in 'area' and a double century break in 'extent', while the only thing of significance that could have caused that is a mild storm on the Pacific side. One that 'normally' should actually cool down things, and cause some dispersion.

The only reasonable explanation for these century breaks seems to be that (as many of us have pointed out before) that the ice in 2017 is simply thinner and thus more sensitive than in prior years, just like PIOMAS told us all along. It's just that the effect of that thinner ice is really starting to show up now at the end of the melting season.

High ice concentration (and 'area') were at the core of my 'high' projection, and I'm starting to feel a bit concerned now that we may see a lot more ice disappear rather than preserved before the end of the season....

43
Arctic sea ice / Re: What the Buoys are telling
« on: August 02, 2017, 08:43:06 AM »
Jim, that was a great find ! Thank you !
The latest image from that 2017A location appears to be this one from July 18 (76.924095,-152.562347) :

It is great to see an image from the Arctic other than Obuoy14.
It looks like the images after July 18 are from a different camera (the one below the surface, looking up). The file sizes are much smaller and even the file names are different :
https://sites.wp.odu.edu/wp-content/uploads/sites/57/2017/07/
I hope they will continue to post images from above the surface, as they tell a great deal about the state of the ice in that location.

44
Arctic sea ice / Re: 2017 sea ice area and extent data
« on: August 02, 2017, 07:53:17 AM »
Um...I've been watching you long enough that I want a translation.

I kinda get how you know the satellite's failings, but I just see the woof and wain without enough understanding of what is real and what is a ghost.

As Wipneus explained a couple of times :
These masks, created by NSIDC, remove any ice from places where we know no ice does exist. As ice in winter can be found much further south than in summer, a different mask has been created for each month.

NSIDC has a good explanation here :
https://nsidc.org/data/pm/ocean-masks

45
Arctic sea ice / Re: The 2017 melting season
« on: August 01, 2017, 08:58:41 AM »
There certainly is a lot of inconsistent evidence. (But perhaps this is to be expected if old trends are starting to break down.)

Sure there is, especially since there are a lot of different measures in that Wipneus' graph.
If we follow AMSR2 3.125 resolution on that graph, it shows that 2017 'area' is currently between 2015/2016 and 2013/2014. Maybe that is where it is heading...

46
Arctic sea ice / Re: The 2017 melting season
« on: August 01, 2017, 08:20:59 AM »
I mean, imagine how 'cool' it would be to have weather that's fit for a rebound year, but the melting season actually ending really low, like Top 3?

That would be interesting, but I'm not sure if we would be able to draw any firm conclusions from it.
For example, PIOMAS volume in 2016 was not that much different from 2017, and 2016 NSIDC clocked in at 4.7. So if 2017 would be much lower than that, would you say that that was because of low ice volume ? And what was the cause if 2017 will be higher ?

47
Arctic sea ice / Re: The 2017 melting season
« on: August 01, 2017, 07:42:08 AM »
I think we can all agree that this has so far been an extraordinary melting season, specifically because we don't know which way it is going.

Early in the season, we had these record low PIOMAS numbers that suggested a record low was upcoming, while Schroeder's May melting-pond measure and that almost record high land snow anomaly that suggested a 'rebound' year was in the works.

Then through the melting season, 'extent' was running near record low, while 'area' was in the the middle of the pack, suggesting 7th place or so.

Now it's August, and we still don't know.
A less-used metric, Arctic-Roos, adds to the uncertainty :
Arctic-Roos extent runs with the champions of extent loss :
http://web.nersc.no/WebData/arctic-roos.org/observation/ssmi1_ice_ext.png

while Arctic-Roos 'area' is heading for 2013/2014 levels :
http://web.nersc.no/WebData/arctic-roos.org/observation/ssmi1_ice_area.png

This season is like a good 'suspense' movie, where the outcome is unknown until the very last scene...

[edit] At some point, something has got to give. Either 'extent' loss will start to slow down, or 'area' loss will speed up. Personally, I think that with average weather it will be the first, since 'area' typically is a better indicator of ice melt than 'extent'.

48
Arctic sea ice / Re: The 2017 melting season
« on: July 30, 2017, 11:11:09 AM »
I'm not sure there is reason to worry about more sustained large declines in extent, guys.

Looking at Wipneus' NSIDC ice concentration numbers, which again shut up recently :
https://sites.google.com/site/arcticseaicegraphs/regional
concentration is now running between 2013 and 2014 levels, this is typically an indication that 'extent' is up for another stall in the next couple of days.

Longer term, looking at the 'area' numbers (typically a better indicator of ice melt than 'extent') 2017 is running in 7th place or so, as Steven pointed out in another thread :



In fact, 'area' runs between 2010 and 2013 levels at this point giving an indication where this season is heading.

Also, 'albedo' numbers according to Nico Sun :
https://sites.google.com/site/cryospherecomputing/warming-potential/graphs
are running in the middle of the pack at 2010, 2015 sort of level, suggesting that there is no a lot of heat input (at least not from 'albedo' sources).

And then there is Slater's model, which is pretty darn accurate at the 50 day lead times.
It just bottomed out (daily minimum) at 4.5 M km^2 or so.
2016 bottomed out at 4.1 and ended up at 4.7 for the (NSIDC) monthly average, so it is very well possible that 2017 will end up in the high 4's or low 5's for NSIDC, putting it in 7th place or so (similar to the 'area' rating at this point).

So even though it doesn't look like 2017 is going with my model projection (of 5.4) of a recovery year, there are plenty of indications it will stall extent in the short term and end up high in September.

49
Arctic sea ice / Re: The 2017 melting season
« on: July 26, 2017, 09:45:44 AM »
From SIPN July report, figure 9 :



I wonder how much that 'dipole' setup contributed to the Beaufort Gyre and ice compaction on the Pacific side and ice dispersion on the Atlantic side between halfway June and halfway July.
The extended range forecast from NOAA/CPC for the end of July 2017 continues a low pressure pattern over the central Arctic (See image, here), suggesting a continuation of only modest sea ice melt in coming weeks.
https://www.arcus.org/sipn/sea-ice-outlook/2017/july


50
Arctic sea ice / Re: Latest PIOMAS update (mid July update)
« on: July 26, 2017, 09:35:19 AM »
Very interesting discussion. Thank you everyone !

A while ago I postulated that the main question is : "does the Arctic summer melt 'extent' or does it melt 'volume' ?".

Intuitively one would expect the latter ; that a given summer provides a given amount of heat which would melt a given amount of volume of ice regardless of where that ice resides.

But it seems that the picture is more complicated than that.

Melting 'extent' lowers albedo, which suggests that thin ice would increase melting rates. Arctic amplification and all that. But even that is not certain, since it takes time for lower latitudes to warm up, and thus this ice might actually slow volume melt rates especially in the latter part of the season when insulation dwindles.

Either way, its remarkable that even now, at the end of July, neither PIOMAS volume numbers nor NSIDC extent and area numbers can tell us where this season is going.
It's yet again an exciting melting season.

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