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crandles

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #500 on: June 18, 2013, 01:32:07 PM »
Uh - not good for ice, ponded area is more translucent (how much?) than unponded areas as shown in "Under Ice Optics" video below.

Actually I would say good for ice. Such factors have been in effect, but now the ice is getting more fragmented, doesn't that mean smaller ponds on smallr pieces of ice? Won't that give a higher ratio of ice without melt ponds above to ice with melt ponds above?

In the past this will have been hidden by MYI changing to FYI which get higher melt pond coverage helping the melt proceed more easily. Fortunately, in future the ice gets harder to melt due to lower melt pond coverage percentage.

Of course it might not be significant enough until it is too late, but every little bit of physics that helps elongate a possible tail helps.

ChrisReynolds

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #501 on: June 18, 2013, 04:07:30 PM »
Chris, would you happen to have the plot for either 2012 or 2013 area (i.e. not the difference plot) at this date? (And perhaps even the same plot for the 2012 minimum area?)

Slow Wing,

I've not done it so far.

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #502 on: June 18, 2013, 04:09:13 PM »
Crandles,

It's hard to balance the reduced ponding and increased open water within the pack (ice albedo effect for both). I'm not at all sure which way the balance would tip.

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #503 on: June 18, 2013, 04:55:52 PM »
CT Area June losses to date in context.

1 to 17 June.


6 to 17 June. 6 June being the approximate start of the June Cliff, based on previous years.


The above images have been rotated after uploading to enable them to fit on page - which is why they look a bit odd (titles on right side etc).

Note that the loss from Annual maximum to 17 June is not unusual for 2013 (-4.934), 2012 (-5.761) remains the greatest loss over that period. The following are the CT Area losses from Max to 17 June.

2007   -4.778
2008   -5.204
2009   -4.584
2010   -5.379
2011   -4.698
2012   -5.761
2013   -4.934

Note that 2007 was unremarkable during this time, as is 2013.

jai mitchell

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #504 on: June 18, 2013, 05:38:28 PM »
That is very impressive Chris.  I am a little surprised because the AMR2 images don't indicate a large amount if area loss yet.  As a newbie it never really made sense to spend so much effort monitoring area.  It seems to me, now that the cryosatII data is accurately determining volume, that this is the much more significant indicator of ice loss.

all of this, to me, is part of figuring out where things are going, what the subsurface melt looks like, is surface enthalpy increases due to center of pack holes going to increase pack loss?  Will Siberian and Canadian archipelago heatwaves melt the periphery ice? 

what will it look like when there is no longer any MYI but we basically reach total melt each year (750 km^3 at September minimum)

the Most important thing in my understanding is, when we do reach that state (in the next few years, I fear) when will we begin to see the june cliff advancing into may?  It is precisely this dynamic that the permafrost models indicate will produce a 3-5C average arctic warming due to loss of albedo.

This shows the intense permafrost melt associated with accelerated sea ice loss.
http://www.colorado.edu/geography/class_homepages/geog_4271_f10/readings/week_10_lawrence_et_al_2008.pdf

This shows how the loss of sea ice leads to a massive increase in the global temperature sensitivity to more carbon dioxide during the peak of prior interglacials.

http://www.iac.ethz.ch/people/knuttir/papers/rohling12nat.pdf

--sorry if this is very much off topic.
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ChrisReynolds

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #505 on: June 18, 2013, 05:54:09 PM »
Jai,

It's the loss of ice in the last ten days that has caused 2013 to have had such a large loss. I await with great interest the rest of June...

Thanks for the Paleosense Team paper.

jdallen

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #506 on: June 18, 2013, 06:24:47 PM »

With 90 or so days to go before the September minimum, that gives 60cm of melt.  Perhaps not quite so insignificant after all?

Quite correct Peter, and it exquisitely illustrates just how sensitive the system is. We will not remain at 1/10 of a degree. Half a degree, and we should reach and pass 2012. More, and it will be stunning.
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jai mitchell

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #507 on: June 18, 2013, 07:12:55 PM »
Chris,

You're welcome,

the scariest sentence in that paper is located under the caption of figure 2,

Quote
. . .which is only considered robust and calculated when T<-1.5K and RF[CO2,LI] < .5Wm–2, (from present) as indicated by the dotted red lines in a and b.

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Apocalypse4Real

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #508 on: June 18, 2013, 11:31:45 PM »
@ Jai, Thanks for both papers, excellent material - and sobering implications for the future.

@ Chris, the tables of the "cliff" are compelling and impressive, we get focused on extent, but the area data is telling the melt story. I hope you'll plot these again at month end.

@ Ktonine, thanks for the refresher on the temp, water, salinity information. I did not describe the entire OSU forecast for the next 5 days, a number of areas have lower than -2 C temps. To support that less than -2 C temps have recently been recorded on a number of buoys under the low pressure, or at land stations in parts of the the Russian Arctic under the influence of the low. Changes in bottom warming will likely offset the refreeze effects, but the low may slow melt out...for a few days.

The latest OSU run has the low moving over the CAA and the beginnngs of the high moving in.

We will see... how the rest of the month melts.

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #509 on: June 19, 2013, 01:40:27 AM »
It looks to me like this ridge must be pumping some major heat into the Arctic. I'm seeing temperatures around 70 not far from the Arctic coast, and in the low 80s not more than 50 miles inland. Interior parts of Alaska have been baking in the upper 80s to mid 90s the last few days.

jdallen

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #510 on: June 19, 2013, 02:08:11 AM »
It looks to me like this ridge must be pumping some major heat into the Arctic. I'm seeing temperatures around 70 not far from the Arctic coast, and in the low 80s not more than 50 miles inland. Interior parts of Alaska have been baking in the upper 80s to mid 90s the last few days.

True, but the primary effect will be on snow covering the pack, rather than direct melt of the ice.  More key is, clear skies, reduction of albedo, melt pools and general clearing of the way for sunlight, followed by requisite heating of sea water.

Hammer and anvil.

Now we see what effect the massive fracturing of the ice has on the thaw.
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ghoti

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #511 on: June 20, 2013, 12:12:44 AM »
Buoy 2012L (O-bouy 7)  is showing both top and bottom melt. The height of the top surface is moving down the the graph.

http://imb.crrel.usace.army.mil/irid_data/2012L_thick.png


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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #512 on: June 20, 2013, 03:03:50 AM »
Buoy 2012L (O-bouy 7)  is showing both top and bottom melt. The height of the top surface is moving down the the graph.

http://imb.crrel.usace.army.mil/irid_data/2012L_thick.png

Interesting. Looks like about 10cm, both top and bottom, or about 7% of the thickness overall. That is a *lot*, this early, compared to the total annual melt in 2007 around that latitude. I'll have to find that paper again.  I posted it somewhere earlier...
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Laurent

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #513 on: June 20, 2013, 09:34:33 AM »
I have difficulties to trust very much the datas from the buoys !
Are they working well, are they vertical...
What is amazing are the buoys 7 and 8, they are suppose to be in the thicker ice of the whole Arctic and they are melting (with a bit of imagination ;)).
http://obuoy.datatransport.org/monitor#buoy8/webcam
Definitively not standing right !
Do you know where are the measurements of thickness for these buoys.

An other question : the jet stream seems to have a double layer skin, sometimes it does look like a spiral ? is that normal ?
« Last Edit: June 20, 2013, 09:44:55 AM by Laurent »

Pmt111500

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #514 on: June 20, 2013, 10:49:25 AM »
yes, things are starting to look critical for Obuoy#8. Estimate of the tilt is 13 degrees. As the meltpools become visible, it is a sign that most of the snow underneath the top layer is in fact slush, so rubber boots aka wellingtons are the only correct ones to use. If one dares to walk on that. There's no way of knowing where the thinnest places underneath the slush layer are. As a kid it was sometimes fun to take a stone or a block of grounded ice and throw it hard on ice looking like that, if it goes through the meltpools vanish pretty quickly.
« Last Edit: June 20, 2013, 12:13:39 PM by Pmt111500 »

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #515 on: June 20, 2013, 11:23:55 AM »
At least O-Buoy 10 is on safe ground for now...  ;D

http://obuoy.datatransport.org/monitor#buoy10/webcam

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #516 on: June 20, 2013, 11:54:33 AM »
Here's my own version of CAPIE, using CT area and NSIDC extent, normalised to keep the values between 0 and 1, the closer to 1, the more dispersed the ice.
Interesting to note how 2007, 2012 and 2013 seem to be separating themselves from the pack at this time of the month.


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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #517 on: June 20, 2013, 04:25:36 PM »
Here's my own version of CAPIE, using CT area and NSIDC extent, normalised to keep the values between 0 and 1, the closer to 1, the more dispersed the ice.
Interesting to note how 2007, 2012 and 2013 seem to be separating themselves from the pack at this time of the month.



That graph shows a lot of things. Not only do 2007, 2012 and 2013 separate from the pack but there is a fairly consistent uptick in dispersion for each 5 year period, beginning in 1984.

Question! Does increased melt lead to more dispersion or does an increase in dispersion lead to more melt? Perhaps both are merely symptoms of the disease? (AGW)

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #518 on: June 20, 2013, 04:50:45 PM »
In the first half of the melting season CAPIE/compactness mostly tells you things about melt ponding. In the second half it's divergence that is the dominant factor.
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crandles

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #519 on: June 20, 2013, 05:08:03 PM »
Question! Does increased melt lead to more dispersion or does an increase in dispersion lead to more melt? Perhaps both are merely symptoms of the disease? (AGW)

I see no doubt over increased melt causes more dispersion at least at this time of year in Arctic - the trends shown in the graph is clearly upward. Also melt some ice with zero dispersion and it won't go negative :) OTOH melt the very disperse ice and dispersion will fall. So the growth of dispersion is self limiting.

More dispersion means more open water around the ice so albedo is lower and this will cause more melt, at least in times of high insolation.

So the answer is both (for what we are considering at the moment). But that doesn't necessarily make either the dominant factor. If the ice has a very high proportion of wafer thin areas then more melt causes more dispersion is an obvious effect. In the absence of this, high pressure causes dispersion to fall while low pressure causes more dispersion may be a more dominant factor.


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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #520 on: June 20, 2013, 06:48:32 PM »
In the first half of the melting season CAPIE/compactness mostly tells you things about melt ponding. In the second half it's divergence that is the dominant factor.

On a related issued, from Kevin O'Neill in comments at my blog (extracts from two comments):

Quote
...If you look at CT area daily numbers versus yearly minimum, the correlation coefficients drop into a notch from mid-June to mid-July. I attribute this to 'false' area losses being recorded due to melt ponds.

Also interesting is that the high melt years (as you noted - 2007,2010,2011, & 2012) all crossed the CT area 6 Mkm^2 mark on day 191 plus or minus a day...

...The melt pond fraction effect on area seems to self-correct by mid-July. I'll be watching closely to see if 2013 can hit that 6 Mkm CT area mark by day 191. If it does, then I expect a new record. If not, then we may see a slight rebound. Still, the difference between the individual 'melt out years' isn't really significant on CT daily area numbers until after August 1st.

The 6M by day 191 does look like an indicator worth considering.

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #521 on: June 20, 2013, 07:54:54 PM »
Here's my own version of CAPIE, using CT area and NSIDC extent, normalised to keep the values between 0 and 1, the closer to 1, the more dispersed the ice.

I have a question about that. You seem to calculate SIE-SIA divided by SIE+SIA.

The SIE-SIA is no problem, it is the area of open water. But what about SIE+SIA??
It is ice counted twice plus the open water, which does not make any sense.

Why not simply SIE-SIA divided by SIE  area of open water by surface of ice+water?

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #522 on: June 20, 2013, 08:03:33 PM »
At the risk of saying something stupid: There's very little ice off the east coast of Greenland, and I'm not sure the SIC maps are catching it because of the haze:



SSTs are pretty high there...

I can't remember having seen that.  :o
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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #523 on: June 20, 2013, 09:28:40 PM »
This is just a thought on divergence, isn't there a special case when you have a PAC hovering around the pole causing an acceleration relative to the earths rotational speed, causing an inevitable shift south of anything caugth by the wind, and a consequential upwelling, etc.

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #524 on: June 20, 2013, 10:50:27 PM »
Following CT reporting…only significant in comparison to earlier years.
The cliff continues.
Roughly 200K more SIA loss than last year in the last 5 days. ECMWF forecasting a low churning near the Pole for some days, than a Beaufort high/dipole up to the end of the month. Right on course. Could be a bit less than -150 a day.
Kara Sea experiencing a good warming mid-week. Hudson Bay some hefty Westerlies that could pretty much clear the way.

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #525 on: June 20, 2013, 11:08:41 PM »
At the risk of saying something stupid: There's very little ice off the east coast of Greenland, and I'm not sure the SIC maps are catching it because of the ...

SSTs are pretty high there...

I can't remember having seen that.  :o

They may not be, but most dismiss ice there as no longer relevant. The images do suggest any ice exiting via the FRAM is being summarily destroyed almost before it passes the gap.
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Neven

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #526 on: June 20, 2013, 11:32:46 PM »
The images do suggest any ice exiting via the FRAM is being summarily destroyed almost before it passes the gap.

Yes, that's what I mean. If transport to Fram Strait would stall for a week or so, and SSTs go up some more, all of it could melt out. Imagine that. No tail...
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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #527 on: June 21, 2013, 01:10:34 AM »
We could see no tail in a 6-10 period.

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #528 on: June 21, 2013, 01:32:11 AM »
We could see no tail in a 6-10 period.

That long? Not a lot there now....

I'm wondering what the shore fast ice will do.

Worthy of note... Lack of tail means ~150k KM2 or so of the Greenland sea is now sucking up sunlight where it hasn't ...
« Last Edit: June 21, 2013, 01:55:25 AM by jdallen »
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ghoti

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #529 on: June 21, 2013, 02:07:43 AM »
Is buoy 2012M on shore ice in the Greenland Sea? The map doesn't show any drift. THe buoy data shows lots of snow melt since June 1 but no noticable bottom melt yet.

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #530 on: June 21, 2013, 02:56:13 AM »
We could see no tail in a 6-10 period.

That long? Not a lot there now....

I'm wondering what the shore fast ice will do.

Worthy of note... Lack of tail means ~150k KM2 or so of the Greenland sea is now sucking up sunlight where it hasn't ...

it's been hit pretty hard for a while and didn't melt out completely.

the Kara is about to get smoked as well as the Hudson.

I'd expect some big extent drops soon.
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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #531 on: June 21, 2013, 07:45:17 AM »
GFS smokes the Pacific and Kara:



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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #532 on: June 21, 2013, 11:24:17 AM »
Here's my own version of CAPIE, using CT area and NSIDC extent, normalised to keep the values between 0 and 1, the closer to 1, the more dispersed the ice.

I have a question about that. You seem to calculate SIE-SIA divided by SIE+SIA.

The SIE-SIA is no problem, it is the area of open water. But what about SIE+SIA??
It is ice counted twice plus the open water, which does not make any sense.

Why not simply SIE-SIA divided by SIE  area of open water by surface of ice+water?

No real reasoning behind it, I just had some stuff set up for NDVI work and slapped the SIE and SIA in instead!

I thought that trying to calculate the open water using measures that have different concentration cut off points (15% and 30%) and different spatial resolutions wouldn't be too effective? Something you could avoid with your own area and extent data?
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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #533 on: June 21, 2013, 06:31:46 PM »
CT Area 8.597M km^2.
0.002M gain on previous day.
0.826M behind 2012 (an increase in the gap).
And an uptick in anomalies.

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #534 on: June 21, 2013, 07:05:14 PM »
When I look at the NSIDC extent map and then compare with NASA worldview, I think extent is highly overestimated and it's just a matter of days, when we'll see a cliff.

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #535 on: June 21, 2013, 07:48:32 PM »
When I look at the NSIDC extent map and then compare with NASA worldview, I think extent is highly overestimated and it's just a matter of days, when we'll see a cliff.

won't take much

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #536 on: June 21, 2013, 07:50:07 PM »
When I look at the NSIDC extent map and then compare with NASA worldview, I think extent is highly overestimated and it's just a matter of days, when we'll see a cliff.

won't take much

My gut says extent is hiding a dirty little secret. I'm no expert and really hope I'm wrong.

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #537 on: June 21, 2013, 08:02:10 PM »
 It might only be me but looks like one of the the large fractures in the Beaufort Sea earlier this year has survived all the ice movement. By it's colour the ice there looks very thin. Interesting to see what happens if it melts out before the rest of the pack and the results of that.

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #538 on: June 21, 2013, 08:59:45 PM »
Spotted that the other day - it's definitely the biggest of the fractures from March, you can track all the way from then until now on ASCAT.

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #539 on: June 22, 2013, 12:36:03 PM »
CT Area occasional uptick/low melt figures this time of year are possibly caused by the melt pools draining, when the weight of the water is off the ice the remainder of the floes rises a bit. Which is why it's advisable to use weekly or longer averages in estimating the true ice loss. (at least three days isn't enough sometimes.)

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #540 on: June 22, 2013, 01:46:15 PM »
After one day’s hickup ( maybe sensors fooled by extensive fog and clouds) CT SIA is back on track with a one-two-three punch.
Minus 208K, adding up to almost a million K less in a week. Closing in on ’12. Two more weeks with this tempo and, indeed, ’13 will be a contender. This was Hudson and Baffin. Waiting for Kara and Beaufort to tune in.
BTW I feel guilt for the enthuisiastic tone. But mankind probably needs a clear signal. If spreading weird weather isn’t enough, maybe an icefree NPole could raise interest?

Pmt, hi, that's why comparing  to other years is more relevant than the daily numbers.

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #541 on: June 22, 2013, 03:06:29 PM »
Happy June solstice, all.  Here's the "forecast" (above) vs. "nowcast" (below) for today's date from the U.S. Navy HYCOM system.  Ice edge retreat has been more rapid in most regions than the week-ago forecast.  The thinned-out area in CAB differs in features, but not a bad prediction considering the unusual combination of conditions that produced it.

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #542 on: June 22, 2013, 03:08:35 PM »
BTW I feel guilt for the enthuisiastic tone. But mankind probably needs a clear signal. If spreading weird weather isn’t enough, maybe an icefree NPole could raise interest?

We can consider us lucky climate change starts at the uninhabited North Pole, imagine Mediterranean Sea had disappeared by fifty percent last 30 years.

ChrisReynolds

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #543 on: June 22, 2013, 05:54:33 PM »
BTW I feel guilt for the enthuisiastic tone. But mankind probably needs a clear signal. If spreading weird weather isn’t enough, maybe an icefree NPole could raise interest?

Why feel guilt? By worrying about this and crying "Woe is me! A 208k drop!" how many cubic metres of ice will you save? The ice will do as it will, why not enjoy watching.

I'm loving it!  8)

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #544 on: June 23, 2013, 01:05:29 AM »
Summer is here!  1M down and counting this week.  If this area loss rate keeps for the next 2 weeks, and I expect it will, 2013 area will draw even with 2012 by the middle of July.  Extent shows no real signs of dropping off a cliff but who cares.  Transportation across the NP is not far away, even if it takes place through a sea of slush.  It might even help keep the barnacles to a minimum.


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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #546 on: June 23, 2013, 02:48:35 PM »
It is a full moon - and a "supermoon" at that.  So I wouldn't be surprised to see some tidal effects.

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #547 on: June 23, 2013, 05:47:36 PM »
It is a full moon - and a "supermoon" at that.  So I wouldn't be surprised to see some tidal effects.

Good! A test. Let us know when you see them.

ktonine

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #548 on: June 23, 2013, 06:01:26 PM »
Given how fractured the pack is already, i think the largest effect tides might have right now is on salt density. From <a href="http://www.ocean-sci.net/7/203/2011/os-7-203-2011.pdf">The effect of tides on dense water formation in Arctic shelf seas</a>:

Quote
Including tides in the model is found to have little impact on overall sea ice extent
but is found to delay freeze up and hasten the onset of melting in tidally active coastal regions. The impact that including tides in the model has on the salt budget is investigated and found to be regionally dependent. The vertically integrated salt budget is dominated by lateral advection. This increases significantly when tides are included in the model in the Pechora Sea and around Svalbard where tides are strong. Tides increase the salt flux from sea ice by 50% in the Pechora
and White Seas but have little impact elsewhere. This study suggests that the interaction between ocean tides and sea ice should not be neglected when modeling the Arctic.

But if there is any large unfractured coastal ice - tides will put stress on it.  I don't follow MODIS close enough to know where that might be.

Jim

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Re: Short to Medium Term Arctic Sea Ice Conditions Discussion
« Reply #549 on: June 23, 2013, 06:37:41 PM »
....well, well - judging by the ice area and extent figures this year, I wasn't too concerned about the ice breaking any records, but then I had a look at the ice thickness maps here at HYCOM/CICE and compared to the same time last year, it looks pretty bad!
Just eyeballing the images, the extent and area are above last year but the 'interior' looks pretty rotten. There appears to be less thick, old ice and the rest looks considerably thinner, than last year. So, given a bit of prolonged irradiance, things could get decidedly dodgy by late August/September  :P
What do you guys think - are these thickness images reliable? Are they a good indicator of things to come?