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EthanOConnor

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Re: Latest PIOMAS update (June)
« Reply #950 on: June 05, 2016, 11:50:58 PM »
   - a band of thinner ice opens up in the mid-section of the >3.75 'white' ice (Q. do we have visual verification of this?).

The timing and orientation of the band of thinner ice both line up well with the cracking event that occurred as a high relocated from the Beaufort up to the pole, shifting the winds to the SE/S across the CAA. This was around May 6th. Hycom replicates the timing but places the thin area to the west of PIOMAS, which I think matches visual evidence better.


Neven

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Re: Latest PIOMAS update (June)
« Reply #951 on: June 07, 2016, 01:32:05 AM »
PIOMAS updated now, 3037 km3 was lost during May.

I'm going to try again and eyeball PIOMAS May volume loss.

blah blah blah

So, around -3000 km3 is my guess, plusminus 100 km3. That would make 2016 lowest on record.
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Tor Bejnar

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Re: Latest PIOMAS update (June)
« Reply #952 on: June 07, 2016, 02:59:05 AM »
This is why we follow you, Neven  ;D
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"

Flocke

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Re: Latest PIOMAS update (June)
« Reply #953 on: June 07, 2016, 06:28:50 AM »
This is why we follow you, Neven  ;D
Because we ... love his eyes?

budmantis

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Re: Latest PIOMAS update (June)
« Reply #954 on: June 07, 2016, 06:32:07 AM »
This is why we follow you, Neven  ;D
Because we ... love his eyes?
Because of the wonderful things he does!

"Pay no attention to the man behind the curtain"!

Juan C. García

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Re: Latest PIOMAS update (June)
« Reply #955 on: June 07, 2016, 06:46:07 AM »
I had not saw that there was a PIOMAS link to Neven Arctic Sea Ice Blog.
Congratulations Neven! Maybe there it was -long time ago- and I didn't notice, but I feel that we are doing science here and now!  ;) ;D

http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/piomas-links/
« Last Edit: June 07, 2016, 06:52:53 AM by Juan C. García »
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Wipneus

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Re: Latest PIOMAS update (June)
« Reply #956 on: June 07, 2016, 08:35:02 AM »
Now PSC has updated their PIOMAS  daily volume data. I updated my graphics, see the top post

From the anomaly graph, we can see the answer to the question whether/how  the glitches in the Barentsz Sea affect the PIOMAS volume.

iceman

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Re: Latest PIOMAS update (June)
« Reply #957 on: June 07, 2016, 11:51:22 AM »
This is why we follow you, Neven  ;D
Because we ... love his eyes?
Because of the wonderful things he does!

"Pay no attention to the man behind the curtain"!

from God's lips to Neven's eyes!

Neven

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Re: Latest PIOMAS update (June)
« Reply #958 on: June 08, 2016, 01:16:44 AM »
Arctic Sea Ice Blog: PIOMAS June 2016
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oren

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Re: Latest PIOMAS update (June)
« Reply #959 on: June 08, 2016, 11:43:18 AM »
Neven, in your PIJAMAS calculation shouldn't it be JAXA area instead of extent?

Neven

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Re: Latest PIOMAS update (June)
« Reply #960 on: June 08, 2016, 01:12:43 PM »
Neven, in your PIJAMAS calculation shouldn't it be JAXA area instead of extent?

I don't know, why? It's just a means to compare years with each other by doing the same things constantly. It shouldn't be regarded as an accurate portrayal of reality, just a handy tool to get the idea.
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OSweetMrMath

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Re: Latest PIOMAS update (June)
« Reply #961 on: June 08, 2016, 10:00:51 PM »
Here's the updated volume anomaly graph. Like last time, all years are shown, years starting at 2010 are in color, and 2016 is a thick black line.

Also keep in mind that this anomaly is computed relative to a baseline which includes a linear trend, so the current anomaly is closer to zero than other recent years even though the actual volume is at a record low.


binntho

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Re: Latest PIOMAS update (June)
« Reply #962 on: June 15, 2016, 07:41:30 AM »
I was struck by an animation on Robert Scribblers blog showing rapid thinning of the ice in the Arctic Basin. The animation shows changes in sea ice thickness over one month, starting on may 20th, taken from the US Navy HYCOM/CICE website.

There is a lot of talk of comparing this year with 2012 so I decided to do the same, looking at two dates each year (may 15th and june 15th), and it seems to my untrained eye that the drop in thickness is greater this year, and that overall thickness is significantly lower -something that doesn't seem to be the case when looking at PIOMAS.

Looking closer at the two dates this year it seems to me that thickness has gone down between 0.5 and 1 meter in more or less the entire basin. Or am I barking up the wrong tree here?

I've attached two images, one showing the two dates from 2012 and 2016 respectively, another showing a close up of the same dates for 2016.
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Laurent

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Re: Latest PIOMAS update (June)
« Reply #963 on: June 15, 2016, 10:15:31 AM »
It is hard to compare because hycom has change the model they use (I think the colors also) in between. For the reality of the thickness that is still an open question today and even more for the quality of the ice. So yes you may be right the ice is thinner this year, that won't surprise me, we are going to 0 some time in the years to come, that's the trend without doubt.

binntho

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Re: Latest PIOMAS update (June)
« Reply #964 on: June 15, 2016, 01:16:30 PM »
It is hard to compare because hycom has change the model they use (I think the colors also) in between.

That may be so - comparison between 12 and 16 may be way off.

But what about the difference over the last month or so? In the second of my two images I compare today with one month ago. I did a very coarse color comparison between the two dates and it seemed to me that thickness overall had gone down between 0.5m and 1m, which is a significant proportion of average thickness (which was around 1.8m at the end of May according to Neven's PIOMAS blog).

It seems to me that according to the US Navy, thickness is going down very fast. I've attached the 30 day animation from the HYCOM site, the thinning is most pronounced towards the very end.
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AmbiValent

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Re: Latest PIOMAS update (June)
« Reply #965 on: June 15, 2016, 01:30:27 PM »
I think that points to a problem with the HYCOM model. Observation shows that thinner ice is more vulnerable to about all kinds of influences leading to melting, especially on the periphery. But the HYCOM model shows ice thickness declining in the center where ice is thickest.
Bright ice, how can you crack and fail? How can the ice that seemed so mighty suddenly seem so frail?

Laurent

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Re: Latest PIOMAS update (June)
« Reply #966 on: June 15, 2016, 01:34:53 PM »
There is an other bias with Hycom, because there is actual thickness and the forecast which will vary (sometimes a lot, they have improve thought). What part of the Arctic are you talking to, it is better if you address a precise area so we can check with modis or over tools what is going on. yes Hycom is showing melting and that is normal, Jdallen is saying 2cm/day, it can be more. There is a newer tool with Hycom showing slightly different view on the melting. https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticictn_nowcast_anim30d.gif I don't know which one best describe reality, as I said previously it is by crossing the informations between tools that we can have a good understanding of what is going on.
« Last Edit: June 15, 2016, 01:45:07 PM by Laurent »

slow wing

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Re: Latest PIOMAS update (June)
« Reply #967 on: June 15, 2016, 01:56:56 PM »
Presumably talking about 8-10 degrees from the N pole and 145-180E longitude.

The HYCOM model appears to show the ice there rupturing/stretching.

binntho

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Re: Latest PIOMAS update (June)
« Reply #968 on: June 15, 2016, 02:27:03 PM »
An apology for being so unclear - and a retraction.

The areas that struck me were the Laptev sea, stretching towards the pole,with a marked deepening of the blue color; the Chukchi sea, not so pronounced deepening but over a larger area; and the Beaufort sea, a deepening of yellow/green and diminishing of red. In fact, almost all of the arctic basin is showing a thinning of ice according to these images.

But for the retraction: I did a more detailed comparisons of colors against the color bar, and found that in those areas mentioned it would indicate a thinning of between 20 and 30 cm, not 0.5 to 1 m as I stated earlier. I guess I got a bit carried away there.

I guess I am still a bit stomped by the rapid changes shown towards the end of the 30 day animation, and by the fact that practically the entire "thick" ice of the arctic basin seems to be thinning. Perhaps this is normal in dispersing ice and does not signify melt.

Anyway, thanks for your replies guys!
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Re: Latest PIOMAS update (June)
« Reply #969 on: June 15, 2016, 02:54:28 PM »
binntho .. important to note that the last 7 days of the annimation are a forecast , not reality , and as such may never happen . However I still anticipate a 'pole hole' of impressive size by end of melt ..
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slow wing

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Re: Latest PIOMAS update (June)
« Reply #970 on: June 15, 2016, 03:14:54 PM »
Yes, the model has the ice dispersing. It also has it being chomped up fiercely in the open water off the Alaskan Arctic coast.

Afaik, this happening to this extent in mid-June would be unprecedented in the satellite record - maybe it happened to a lesser extent in 2012.

Whether the model is realistic in this aspect is hard for me to tell. Anyone more expert than me to comment?

Laurent

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Re: Latest PIOMAS update (June)
« Reply #971 on: June 15, 2016, 03:38:10 PM »
As I posted in the melting season, the ice is highly fractured in the area 82N 150W to me that has never happened before so early, but like you slow wing I am not an expert... On the Laptev side that has already happened, knowing if we are earlier than anything at this stage may be a stretch, this area should melt completely and then we will have a better idea how it does compare to 2012 or an other year. For the moment there is some rubble appearing on Modis in Laptev, Hycom doesn't show that, it would be cool to have a tool like the Beaufort forecast which show a lot more details, I really like the strength tool. http://www7320.nrlssc.navy.mil/hycomARC/beaufort.html

etienne

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Re: Latest PIOMAS update (June)
« Reply #972 on: July 01, 2016, 09:20:37 AM »
Hello,

Here is the same graph that I did for the Sea Ice Extend

but with Piomas Data. Graph has been updated with the data of June 2016

Monthly average in blue, yearly average in red, trend in yellow. I used the data from here:
http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/

Trend is about 25 km^3 per month (0.25  1000km^3 in the units of the graph above).

Just like for the sea ice extend, this graphs shows that we would be in a normal melt year. Maybe this is because today's yearly average is still half on 2015 which was a lower melting year.

I also have a graph where the difference with the trend of the average extend and of the average PIOMAS can be compared.



Regards,

Etienne
« Last Edit: July 06, 2016, 10:14:45 AM by etienne »

Neven

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Re: Latest PIOMAS update (June)
« Reply #973 on: July 04, 2016, 03:57:30 PM »
Okay, I know I shouldn't, but I'm playing the eyeball game again. Here's the volume decline during June:



And here are the SAT and SLP maps for both halves of June:



The first half of June looks very similar to that of 2013 wrt both SAT and SLP, and maybe just a little like 2015. They both lost around 2800 km3.

For the second half of June this year again looks most similar to 2013, and there are some similarities with 2012 and 2015. The average of those three years is 3600 km3.

That makes the total 6400 km3, but I'm going to add 100 km3, because of the heat wave over the ESS at the start of the month (where the ice is supposed to be really thick this year).

So, my guess is that total June volume loss will come in at around 6500 km3, plusminus 100km3. That would take 2016 into second place, around 500 km2 higher than 2012.

I wouldn't be surprised if June total volume loss is lower, but this is what my eyeballs are saying.
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plinius

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Re: Latest PIOMAS update (June)
« Reply #974 on: July 04, 2016, 07:36:30 PM »
I think that points to a problem with the HYCOM model. Observation shows that thinner ice is more vulnerable to about all kinds of influences leading to melting, especially on the periphery. But the HYCOM model shows ice thickness declining in the center where ice is thickest.

I think that is rather a problem with your understanding of what is plotted. Average ice thickness means that if on a grid cell the concentration plummets, the average ice thickness will do so too, though it is only dispersion of small floes. Hycom has a bunch of problems, but this one isn't.

Lord M Vader

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Re: Latest PIOMAS update (June)
« Reply #975 on: July 04, 2016, 08:34:34 PM »
Neven, given the weather conditions during June, I believe a volume loss of 5700-5900 km3 is s more reasonable number. IMO June 2016 seems somewhat similar to 2014 but with a more sloshy ice. Of course, this is only a lot of speculation but funny to see what the PIOMAS number will be  :)

Wipneus

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Re: Latest PIOMAS update (July)
« Reply #976 on: July 05, 2016, 10:26:13 AM »
Gridded monthly and daily PIOMAS data are in. Maps will follow later.

Official volume data not in but I estimate the final value (day 182) will be 13.176 [1000 km3].


magnamentis

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Re: Latest PIOMAS update (July)
« Reply #977 on: July 05, 2016, 10:34:47 AM »
Gridded monthly and daily PIOMAS data are in. Maps will follow later.

Official volume data not in but I estimate the final value (day 182) will be 13.176 [1000 km3].

that would be very low if my look into piomas graphs didn't fool me, very low indeed, so low that i suspect i got it wrong, how does it compare?

Wipneus

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Re: Latest PIOMAS update (July)
« Reply #978 on: July 05, 2016, 10:36:31 AM »
Here is the animated PIOMAS thickness of June 2016.
« Last Edit: July 05, 2016, 02:58:00 PM by Wipneus »

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Re: Latest PIOMAS update (July)
« Reply #979 on: July 05, 2016, 10:44:17 AM »
Here is the (average) thickness map in June, and comparisons with previous years.

AmbiValent

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Re: Latest PIOMAS update (July)
« Reply #980 on: July 05, 2016, 10:45:29 AM »
Gridded monthly and daily PIOMAS data are in. Maps will follow later.

Official volume data not in but I estimate the final value (day 182) will be 13.176 [1000 km3].

that would be very low if my look into piomas graphs didn't fool me, very low indeed, so low that i suspect i got it wrong, how does it compare?

My eyeballs say above 2011 and 2012 and below all other years in the record.
Bright ice, how can you crack and fail? How can the ice that seemed so mighty suddenly seem so frail?

Richard Rathbone

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Re: Latest PIOMAS update (July)
« Reply #981 on: July 05, 2016, 11:05:03 AM »
Gridded monthly and daily PIOMAS data are in. Maps will follow later.

Official volume data not in but I estimate the final value (day 182) will be 13.176 [1000 km3].

That's not looking good for Neven's eyeball.

Andreas T

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Re: Latest PIOMAS update (July)
« Reply #982 on: July 05, 2016, 12:17:35 PM »
Gridded monthly and daily PIOMAS data are in. Maps will follow later.

Official volume data not in but I estimate the final value (day 182) will be 13.176 [1000 km3].

that would be very low if my look into piomas graphs didn't fool me, very low indeed, so low that i suspect i got it wrong, how does it compare?
It isn't very low for the end of June. The value given by Wipneus is a daily value for day 182, not the monthly average for June plotted in his graph at the top of the thread if I am not mistaken

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Re: Latest PIOMAS update (July)
« Reply #983 on: July 05, 2016, 12:51:52 PM »
Gridded monthly and daily PIOMAS data are in. Maps will follow later.

Official volume data not in but I estimate the final value (day 182) will be 13.176 [1000 km3].

that would be very low if my look into piomas graphs didn't fool me, very low indeed, so low that i suspect i got it wrong, how does it compare?



2009 182  16.266
2010 182  13.258
2011 182  12.665
2012 182  12.078
2013 182  13.760
2014 182  14.480
2015 182  15.066

13.176 looks 3rd lowest after 2012 and 2011. 2010 close, only 0.082 higher

magnamentis

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Re: Latest PIOMAS update (July)
« Reply #984 on: July 05, 2016, 01:03:27 PM »

2009 182  16.266
2010 182  13.258
2011 182  12.665
2012 182  12.078
2013 182  13.760
2014 182  14.480
2015 182  15.066

13.176 looks 3rd lowest after 2012 and 2011. 2010 close, only 0.082 higher

@Andreas T

thank you both, the graph which i was looking at was the monthly average, well concluded, sorry for the extra round but now i got it, i'm at times too visual and don't pay sufficient attention to titles and text  ;)
« Last Edit: July 05, 2016, 01:09:03 PM by magnamentis »

slow wing

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Re: Latest PIOMAS update (July)
« Reply #985 on: July 05, 2016, 01:30:16 PM »
Thanks, Wipneus, the monthly updates in the melt season are particularly interesting.


Here is the animated PIOMAS thickness of June 2016.
Presumably just my problem but I only get a download of 101 kb that is on 1 June.

Wipneus, after all this great work could I still ask you to post the thickness map for the last day, 30 June?

oren

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Re: Latest PIOMAS update (July)
« Reply #986 on: July 05, 2016, 01:46:11 PM »
So if I calculate it correctly the loss during June was around 6000 km3. Far less than Neven's (typically spot-on) estimate of 6500.

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Re: Latest PIOMAS update (July)
« Reply #987 on: July 05, 2016, 02:59:52 PM »
animation should work now.

Wipneus

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Re: Latest PIOMAS update (July)
« Reply #988 on: July 05, 2016, 03:01:03 PM »
thickness map 30 June

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Re: Latest PIOMAS update (July)
« Reply #989 on: July 05, 2016, 06:06:14 PM »
So if I calculate it correctly the loss during June was around 6000 km3. Far less than Neven's (typically spot-on) estimate of 6500.

8.3% off makes a pretty good guess.. what did u expect, omniscience?

seaicesailor

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Re: Latest PIOMAS update (July)
« Reply #990 on: July 05, 2016, 06:14:22 PM »
So eyeballing the simulation in the Beaufort region, in relation with the current discussions, PIOMAS effective thickness does not start to diminish until past the first week of June. Since then, close to 1 meter of effective thickness is gone almost everywhere where there was ice in that region. That is 5 centimeters per day approximately of effective thickness; since the ice was (is) broken in the Beaufort sea, the real bottom melt must be much higher, perhaps 8 cm per day or more?

I don't think I can estimate bottom melting better than a model such as PIOMAS, can anybody?

Another detail: PIOMAS shows fast bottom melting up to the mouth of the Northwest Passage, and at this rate it may be clear of ice by the end of the month (the mouth, not the full passage).
« Last Edit: July 05, 2016, 06:44:35 PM by seaicesailor »

seaicesailor

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Re: Latest PIOMAS update (July)
« Reply #991 on: July 05, 2016, 07:25:19 PM »
Another interesting things and sorry for double-posting:
- The belt of thicker ice between the CAB and the ESS is going to be right under the heat. That may help the melt front progress from the periphery inwards later. It may change Slater's predictions
- The belt of thicker ice OTOH may hold the Arctic from 'falling apart' :P It is king of a safety belt :P when the cleavage fails
- PIOMAS estimated very thick ice in a small corner of Chukchi ... and there it is. It estimated very thick ice in ESS, and there it is. No much melt in CAB (except Atlantic side), and see below the resucitated 2015F.

Tealight

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Re: Latest PIOMAS update (July)
« Reply #992 on: July 05, 2016, 07:55:31 PM »
I don't think I can estimate bottom melting better than a model such as PIOMAS, can anybody?

The only better estimates are CryoSat's 2 measurements, but they are not available in summer.

My own volume calculations from my "Arctic sea ice Forecast model" are 5900 km3 volume loss. This value is mostly based on sea ice concentration and not ice drift into warmer waters so I believe the actual loss is a bit higher.




oren

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Re: Latest PIOMAS update (July)
« Reply #993 on: July 05, 2016, 08:46:41 PM »
Here is the animated PIOMAS thickness of June 2016.

The animation shows again the amazing development in the Greenland Sea towards the end of the month.

jdallen

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Re: Latest PIOMAS update (July)
« Reply #994 on: July 05, 2016, 09:01:44 PM »
Here is the animated PIOMAS thickness of June 2016.

The animation shows again the amazing development in the Greenland Sea towards the end of the month.
Two things - export shut down and the water heated up even more.

When it starts back up, it will be running into conditions quite a bit more hostile than June, and likely won't be able to push much past the margin we see now, at least, not until fall.
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jdallen

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Re: Latest PIOMAS update (July)
« Reply #995 on: July 05, 2016, 09:10:52 PM »
Here is the animated PIOMAS thickness of June 2016.

The animation shows again the amazing development in the Greenland Sea towards the end of the month.
In fact, here's an excellent clear weather 1KM scale shot today of the area in Worldview including the area north of Svalbard.

It illustrates quite well just how much the heat in the water tears up the ice as it approaches Svalbard and the regions of the Greenland Sea SW of Svalbard and SSE of the Fram gap.
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Neven

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Re: Latest PIOMAS update (July)
« Reply #996 on: July 05, 2016, 11:43:57 PM »
That's not looking good for Neven's eyeball.

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ktonine

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Re: Latest PIOMAS update (July)
« Reply #997 on: July 06, 2016, 12:24:37 AM »
If one looks at Wipneus's PIOMAS thickness graph for June 30 north of Corwallis Island one will find ice over 1m thick.  As Wayne Davidson points out, DMI (and NASA EOSDIS) for July 3 and 4 -- just a few days later --  shows open water over much of the same area. This isn't a 'hole' that's opened up due to wind or shifting ice (as is the case south of Cornwallis Island).

The obvious question is: Can ice 1m or thicker melt out in 3 days time?  I don't think so.  I.e., the ice wasn't 1m thick on June 30th.  I would suggest it was considerably less thick and something (Wayne posits snow cover) fooled PIOMAS into thinking it was that thick.

There are a couple of other areas in the CAA where DMI shows stretches of open water where PIOMAS on June 30 had 1m or thicker ice that are unlikely due to transport.

Here's the image from Wayne Davidson's EH2R blog:




« Last Edit: July 06, 2016, 02:48:15 AM by ktonine »

Wipneus

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Re: Latest PIOMAS update (July)
« Reply #998 on: July 06, 2016, 08:25:22 AM »
ktonine, Wayne's post was about the ice in the Barrow strait. Clouds cover the open water in the first two frames, and is not ice.
Passive microwave can see through the clouds. The attached  animation shows that open water has existed north of Cornwallis island at least for the past one and a half month. No surprise it appears there every year due, no doubt, to up welling currents.

Wipneus

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Re: Latest PIOMAS update (July)
« Reply #999 on: July 06, 2016, 08:37:29 AM »
Now PSC has updated their PIOMAS  daily volume data. I updated my graphics, see the top post

Attaching my anomaly graph.