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Rich

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Re: 2019 sea ice area and extent data
« Reply #1150 on: June 15, 2019, 09:49:51 AM »
If there were ever a piece of data demonstrating the limits of it's utility....the last two days of extent gain tell a story complete out of synch with the substance of what is happening in the Arctic.

For what it's worth, I have no reason to believe the extent numbers are not accurate. The wind is probably spreading ice out in a few places.

The dissonance between the extent and area data is simply incredible.
« Last Edit: June 15, 2019, 10:35:42 AM by Rich »

b_lumenkraft

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Re: 2019 sea ice area and extent data
« Reply #1151 on: June 15, 2019, 10:09:56 AM »
If there were ever a piece of data demonstrating the limits of it's utility....the last two days of extent gain tell a story complete out of synch with the substance of what is happening in the Arctic.

Or is it? What are the sensors picking up? Context is important.

https://forum.arctic-sea-ice.net/index.php/topic,2591.msg205831.html#msg205831

Rich

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Re: 2019 sea ice area and extent data
« Reply #1152 on: June 15, 2019, 10:47:26 AM »
Do you have a point to make to make b_l ?

My point is that there can't be more ice in the Arctic than there was two days ago. Nearly the entire region is above freezing, some by quite a bit.

Does the area measure give a false positive when there  is surface melt and ice remains below? Apparently so.

But the story that extent is telling (which I acknowledged may be an accurate measure of extent) is clearly out of synch with the heat in the Arctic.

There is no way that there is more ice in the Arctic than there was two days ago. 

be cause

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Re: 2019 sea ice area and extent data
« Reply #1153 on: June 15, 2019, 10:56:39 AM »
.. area may go up 100,000 km today .. and yet it a sign of melt progression . melt ponds formed .. mistaken for open sea . Melt ponds drain .. re-recognized as ice .. degrading , but still ice . This has been an interesting lesson in the weaknesses in mid-season measurements .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

b_lumenkraft

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Re: 2019 sea ice area and extent data
« Reply #1154 on: June 15, 2019, 11:03:34 AM »
Do you have a point to make to make b_l ?

Yes. You said:

Quote
If there were ever a piece of data demonstrating the limits of it's utility

And then i hinted that it might be only a limitation of its utility if you don't consider the context while providing the context.

Stephan

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Re: 2019 sea ice area and extent data
« Reply #1155 on: June 15, 2019, 11:29:43 AM »
It could also be that Kara and Barents are essentially flat, and the CAB may have an uptick in its Atlantic side and adjacent to CAA.
[...]
Kara and Beaufort and the worst locations to suffer dispersion right now.
Really bad, the weather
If I consider Aluminium's posting in the 2019 melting season thread https://forum.arctic-sea-ice.net/index.php/topic,2591.msg205756.html#new it is mainly Beaufort and Barents which gained a lot of ice by dispersion from the CAB. This can explain the area gain in the last two days, which, volume-wise, probably is no gain at all.
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pauldry600

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Re: 2019 sea ice area and extent data
« Reply #1156 on: June 15, 2019, 12:12:31 PM »
The pink "ice arrow" shape is beginning to form once again on uni bremen map.

Extent may be going up but only because thin ice spreads out further as it melts..

Could be a pffft day where loss goes 30k one day to 200k the next

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1157 on: June 15, 2019, 12:59:56 PM »
The various sensors and the various algorithms that interpret the sensors' signals are unchanged for a good few years, i.e. have a consistent and unchanging response to stimuli. So if the results that come out are odd, very odd, with unprecedented variation between them there must be a cause i.e. something unusual is happening in at least part of the Arctic seas..

So rather than comment on the limitations of the sensors, a better conversation might be about what are these changes in the Arctic that are causing these weird results in the data? Haphazard may well be right - the nature of the ice in large parts of the Arctic has perhaps changed. I remember A-team's post on the weirdo clockwise rotation of the Arctic ice that's been ongoing for months and his suggestion that it might presage the beginning of the end for the icepack.

If the extent and area sensors + algorithms are getting confused, what are the prospects for the errors in thickness measurements of thin fractured, broken up and dispersed ice from which the volume is estimated? Perhaps the extent of such difficulties might show especially in large variations in the PIOMAS daily volume change data - unless it is already smoothed for easier consumption.
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Sterks

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Re: 2019 sea ice area and extent data
« Reply #1158 on: June 15, 2019, 01:15:20 PM »
No need to resource to a possible change in the ice. The ice has changed, is younger and a 10-20% thinner, or so. But  it's still ice.
There is a surface melting event of (un) precedented reach (since 2012) so NDSIC area goes down because it's too sensitive to surface melt, it even "sees" open ocean where there is not.
Extent is not sensitive, the way it is constructed from same ice concentration data. It does not mistake surface melt by ocean, praised be.
Storms cause ice divergence, a separation of big and small floes between themselves like Mr Wilson and Tom Hanks.
Many of these separations are small growing cracks in regions that had been compacted by the previous anticyclone.
Right now two storms are beating regions very prone to this dispersion and divergence: Beaufort and Kara-Barents.
« Last Edit: June 15, 2019, 01:24:40 PM by Sterks »

Pagophilus

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Re: 2019 sea ice area and extent data
« Reply #1159 on: June 15, 2019, 02:14:33 PM »
I notice that the University of Bremen sea ice concentration page, based on AMSR2 data, is currently down/not accessible.   Are they just as puzzled as we are?

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1160 on: June 15, 2019, 02:20:44 PM »
NSIDC Total Area as at 14 June 2019 (5 day trailing average) 8,648,482  km2
               
Total Area         
 8,648,482    km2      
-316,421    km2   <   2010's average.
-358,489    k   <   2018
-953,931    k   <   2000's average.

Total Area Change   -154    k   loss
Peripheral Seas   -27    k   loss
Central Seas__   -120    k   loss
Other Seas___   -7    k   loss
         
Peripheral Seas         
Bering _______   -0    k   loss
Baffin  Bay____   -19    k   loss
Greenland____   -7    k   loss
Barents ______   -0    k   loss
         
CAB Seas         
Beaufort_____    4    k   gain
CAA_________   -20    k   loss
East Siberian__   -33    k   loss
Central Arctic_   -24    k   loss
         
Kara_________   -12    k   loss
Laptev_______   -27    k   loss
Chukchi______   -7    k   loss
         
Other Seas         
Okhotsk______   -0    k   loss
St Lawrence___    0    k   gain
Hudson Bay___   -6    k   loss

Area loss 154 k, 66 K MORE than the 2010's average loss of 88 k on this day.
Total area still 3rd lowest (101 k greater than 2016, and 242 k greater than 2012).
 
Other Stuff
GFS shows temperature anomalies look very odd so not given Is this the new version of GFS at work ?

However, the images still suggest high +ve anomalies at various times along the coastal fringes of Eastern and Central Siberia and the entire coastal fringe of Alaska, Canada and Greenland mixed with contrasting -ve anomalies at times especially on the American side in the Beaufort and CAA, and NE Europe.

You don't see such a rapid change in the 5 day average loss or such high daily loss very often, especially 2 days in a row, though 2012 was dropping even faster. How long will it last?

Note that NSIDC daily extent increased in the last 3 days  and is now back to 5th lowest by a smidgeon, and that JAXA daily extent loss continued at below average until increasing by 6 k and 14k in the last 2 days.. So  when looking at differences with 2012 and 2016, the area data is converging strongly to the extent data.
_______________________________________________________________
Interesting times over the next few days? I think that for myself from now on I will only call Arctic Ice lowest when JAXA extent and NSIDC extent and NSIDC area all show it.
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Neven

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Re: 2019 sea ice area and extent data
« Reply #1161 on: June 15, 2019, 02:42:04 PM »
There is no way that there is more ice in the Arctic than there was two days ago.

No, but there may be more sea ice extent than there was two days ago, simply because of the way it is measured.

There's nothing strange going on. Extent will start dropping soon enough again.

Quote
The dissonance between the extent and area data is simply incredible.

This dissonance actually tells us something about the ice pack that we wouldn't know otherwise: It is becoming less compact.

Today, yet again, area has dropped by 110K, but because extent has gone up again by 35K, compactness has dropped yet another 1.3%. I think that a drop this straight and long is unprecedented, at least in the 2005-2019 timeframe. But I'm not sure if this rate can be kept up for much longer.
« Last Edit: June 15, 2019, 03:03:12 PM by Neven »
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Jim Pettit

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Re: 2019 sea ice area and extent data
« Reply #1162 on: June 15, 2019, 02:44:23 PM »
Since 2002, NSIDC Arctic Sea ice extent has never seen three consecutive days of increase in June. And most of the previous times there's been even a single day of alleged growth in June, that day (or those days) have been sandwiched between, or immediately adjacent to, very large decreases.

For example. 2014 saw two consecutive days of growth, but those were immediately preceded by a drop of 210k, and immediately followed by a two-day decrease of 278k. 2007 had a drop of 124k sandwiched between increases of 69k and 13k. 2002 had a drop of 120k, then a rise of 8k, then a drop of 109k. And even big bad 2012 had a rise of 5k--followed by a 10-day ice feast that saw the loss of 1.3M.

My prediction, then, based on observation, climatology, and history: 2019 is about to see a very large--perhaps even record-breaking--drop in ASI extent.

Because This here? It ain't normal. And that means something:


b_lumenkraft

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Re: 2019 sea ice area and extent data
« Reply #1163 on: June 15, 2019, 02:51:00 PM »
Hello Jim, so nice to meet you! Didn't know you are a forum member. Shame on me. ;)

I enjoyed and shared your data visualisations quite a lot. Great work!

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Re: 2019 sea ice area and extent data
« Reply #1164 on: June 15, 2019, 02:53:43 PM »
I agree.  There is nothing "strange" that can't be explained going on, but it IS very unusual, or as Jim says, unprecedented. It supports the overall narrative that as the arctic approaches a state change, its behavior becomes more erratic and variable.  The spinning top is wobbling.

uniquorn

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Re: 2019 sea ice area and extent data
« Reply #1165 on: June 15, 2019, 03:40:05 PM »
Since 2002<snip>
Doesn't 2018 show a similar rise in a few days time?

Clenchie

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Re: 2019 sea ice area and extent data
« Reply #1166 on: June 15, 2019, 04:54:37 PM »

My prediction, then, based on observation, climatology, and history: 2019 is about to see a very large--perhaps even record-breaking--drop in ASI extent.



Jim, I like your reasoning and subsequent prediction.  There doesn't necessarily need to be a big drop straight off though, it could happen more slowly and still validate your argument.
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Retron

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Re: 2019 sea ice area and extent data
« Reply #1167 on: June 15, 2019, 05:47:29 PM »
My prediction, then, based on observation, climatology, and history: 2019 is about to see a very large--perhaps even record-breaking--drop in ASI extent.
That sounds like a sensible prediction to me!

I would agree with those who've posted to say that it's the melt ponds confusing the sensors and that we're primed for a swift break-up of the Laptev fast ice; it seems that we've gone through what usually takes a couple of weeks in less than a week.

This GIF of part of Laptev shows it well... we go from fast ice, to "blue" fast ice awash with surface melt (which appeared as water in Bremen charts, for example), to a whiteish drained ice state (which appears as ice again to the sensors).

However, I would imagine that drained ice isn't going to hang around much, it reminds me of a slush puppy after you've sucked out all the flavouring, leaving just clear slush behind!

(The GIF runs from the 7th to the 14th June, a frame a day).

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1168 on: June 15, 2019, 05:59:30 PM »
The University of Bremen has gone off-line
This GIF of part of Laptev shows it well... we go from fast ice, to "blue" fast ice awash with surface melt (which appeared as water in Bremen charts, for example),
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Retron

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Re: 2019 sea ice area and extent data
« Reply #1169 on: June 15, 2019, 06:00:53 PM »

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1170 on: June 15, 2019, 06:17:07 PM »
The University of Bremen has gone off-line

Hmm, it's working here?

https://seaice.uni-bremen.de/data/amsr2/today/Arctic_AMSR2_nic.png
Lucky ? - from there can't look at the other stuff?
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Retron

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Re: 2019 sea ice area and extent data
« Reply #1171 on: June 15, 2019, 06:27:02 PM »

Lucky ? - from there can't look at the other stuff?
You can look up other days' charts by tinkering with the URL below:

https://seaice.uni-bremen.de/data/amsr2/asi_daygrid_swath/n6250/2019/jun/Arctic/asi-AMSR2-n6250-20190613-v5.4_nic.png

(Note that for other months you'll need to change the /jun/ bit as well as the date in the filename).

If you know exactly what you're after, you can browse the files here:

https://seaice.uni-bremen.de/data/

Looks like it's just the homepage which is down, the actual files are fine.

Pagophilus

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Re: 2019 sea ice area and extent data
« Reply #1172 on: June 15, 2019, 06:54:30 PM »
Despite the headline extent numbers being what they are, anyone who becomes complacent at this stage is not looking at the whole picture. Look at the ice that is supposed to survive the melting season, the one in the inner basin. Look at its current area.

In fact, anything but complacency is warranted, if you take the current area and extent changes at face value.  Area is dropping, which most probably indicates less ice is present.  Extent is growing, which means that ice is being more widely distributed through the seas.  It follows that this spreading ice is more likely to melt out even faster in the coming days and weeks (as the distributed floes come in contact with waters that have not been precooled by the melting of adjacent floes.) 

So this gain in extent, if it is real, is a warning sign for the future, and an ominous one.

Pagophilus

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Re: 2019 sea ice area and extent data
« Reply #1173 on: June 15, 2019, 07:22:50 PM »

The NSIDC daily extent data will be interesting, especially after the big hoo-hah in the media about ice extent being lowest. This is what the NSIDC documentation about their data says..

Quote
In these tables, the number of significant figures is not a reflection of true geophysical significance. Here, the number of significant figures implies a precision for measurements of Arctic or Antarctic-wide extent that is better than about 10,000 (0.01 million) sq km, or about 0.2% of a typical 6 million sq km Arctic ice extent. However, uncertainty in daily passive microwave estimates of Arctic-wide extent due to noise in the data and sensitivity to brightness temperatures is on the order of 30,000-50,000 sq km or 0.03-0.05 million sq km (personal communication, Walt Meier 05 Oct. 2016).

Well worth remembering, especially if our ears perk up when we see an unusual single day change.

I assume that the 5 day trailing averages you often use on graphs, smoothing data, are useful in leaving us less susceptible to such uncertainty.  Is this assumption warranted or is there something I don't know? 

And another quick question:   Let us say that the uncertainty stated above  is 50,000 sq km, then does that mean the uncertainty is plus or minus 25,000 sq km; or plus or minus 50,000 sq km?

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Re: 2019 sea ice area and extent data
« Reply #1174 on: June 15, 2019, 07:46:59 PM »
For 6.14., NSIDC sea ice extent is now in 5th place with a value of 10.842 millions of kilometers squared. 2019 now has greater sea ice extent for the date than 2018, 2016, 2012, and 2010. There have now been 3 straight days of gains in the data set.

One more day of gains, or a loss of less than 27,000 kilometers squared, will put us in seventh place for 6.15.

Shared Humanity

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Re: 2019 sea ice area and extent data
« Reply #1175 on: June 15, 2019, 07:47:54 PM »


There is no way that there is more ice in the Arctic than there was two days ago.

And increases in SIE does not tell you there is more ice in the Arctic. It tells you that this ice is spread across more water.

JayW

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Re: 2019 sea ice area and extent data
« Reply #1176 on: June 15, 2019, 07:53:41 PM »
Slater model suggests sea ice is moving from where it's hard to melt, to where it's easy to melt. 


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Shared Humanity

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Re: 2019 sea ice area and extent data
« Reply #1177 on: June 15, 2019, 07:55:28 PM »

Area is dropping, which most probably indicates less ice is present.  Extent is growing, which means that ice is being more widely distributed through the seas.  It follows that this spreading ice is more likely to melt out even faster in the coming days and weeks (as the distributed floes come in contact with waters that have not been precooled by the melting of adjacent floes.) 

So this gain in extent, if it is real, is a warning sign for the future, and an ominous one.

I agree with everyone here. We are looking at a cliff.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1178 on: June 15, 2019, 08:12:16 PM »

I assume that the 5 day trailing averages you often use on graphs, smoothing data, are useful in leaving us less susceptible to such uncertainty distorting our view of the changes in the ice.  Is this assumption warranted or is there something I don't know? 

And another quick question:   Let us say that the uncertainty stated above  is 50,000 sq km, then does that mean the uncertainty is plus or minus 25,000 sq km or plus or minus 50,000 sq km?
NSIDC does say the area measurements are more prone to error which is why the prefer to use the 5 day trailing average.

I am so good to you. A paper by the gurus of gurus, especially Walter Meier. (You know he is of the best as he is a regular target of realclimate.org and wattsupwiththat).

https://iopscience.iop.org/article/10.1088/1748-9326/aaf52c/pdf

Quote
Abstract
The uncertainties in sea ice extent (total area covered by sea ice with concentration >15%) derived from passive microwave sensors are assessed in two ways. Absolute uncertainty (accuracy) is evaluated based on the comparison of the extent between several products. There are clear biases between the extent from the different products that are of the order of 500 000 to 1 × 106 km2 depending on the season and hemisphere. These biases are due to differences in the algorithm sensitivity to ice edge conditions and the spatial resolution of different sensors. Relative uncertainty is assessed by examining extents from the National Snow and Ice Data Center Sea Ice Index product. The largest source of uncertainty,∼100 000 km2 , is between near-real-time and final products due to different input source data and different processing and quality control. For consistent processing, the uncertainty is assessed using different input source data and by varying concentration algorithm parameters. This yields a relative uncertainty of 30000–70 000 km2. . The Arctic minimum extent uncertainty is ∼40 000 km2. Uncertainties in comparing with earlier parts of the record may be higher due to sensor transitions. For the first time, this study provides a quantitative estimate of sea ice extent uncertainty

A good analyst is good at finding data, including that not directly related to the topic under discussion. E.g. this is how the paper ends... with a warning that the record of sea-ice extent and area is under immediate threat. Never gets reported anywhere.

Quote
The passive microwave sea ice record is one of the longest satellite-derived climate records and one of the most iconic indicators of climate change. However, this long-term record is threatened. The existing passive microwave sensors used by the community for sea ice extent are aging. As of this paper (December 2018), the newest sensor, AMSR2, is over six years old, already past its nominal 5-year mission. The current DMSP SSMIS sensors have been operating at least eight years, and the oldest (on F16) was launched more than 14 years ago. The US Department of Defense, JAXA, and the European Space Agency have plans to launch new passive microwave sensors, but these are in their incipient stages and the earliest launch is likely to be at least five years in the future. China has a passive microwave sensor on its FY-3C satellite and future launches are planned. However, there is still a growing potential for a gap in the passive microwave record. If such a gap occurs, intercalibration between sensors would not be possible and the quality of the long-term sea ice extent climate indicator would be degraded. This would be a significant loss to the climate monitoring community.
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magnamentis

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Re: 2019 sea ice area and extent data
« Reply #1179 on: June 15, 2019, 08:23:54 PM »
Slater model suggests sea ice is moving from where it's hard to melt, to where it's easy to melt.

looking like this:
« Last Edit: June 15, 2019, 08:46:43 PM by magnamentis »

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Re: 2019 sea ice area and extent data
« Reply #1180 on: June 15, 2019, 08:26:22 PM »
Slater model suggests sea ice is moving from where it's hard to melt, to where it's easy to melt.

The Slater model puts aug 4th extent at 5,89 m km2. 2012 had 6,15 m km2 extent at that date. 2016 had 6,38 m km2. Interesting

Stephan

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Re: 2019 sea ice area and extent data
« Reply #1181 on: June 15, 2019, 08:37:34 PM »
"relative area change" analysis of the last 16 days presented in gerontocrat's tables.

There are two seas with almost no changes/even slight increases:
CAB and Grønland

There are three seas with [almost] no ice at all, which cannot contribute anymore to total loss:
Okhotsk, St. Lawrence, Bering

And there are seas that constantly lose ice:
around 11% loss: ESS* and Kara
around 15% loss: Chukchi, CAA* and Beaufort
between 24-33% loss: Hudson, Laptev, Baffin and Barents,

The latest acceleration of the seas close to Siberia will change that ranking list, if the weather patterns remain for some time.

* these two seas were in the "no change at all" league when I did that analysis two weeks ago!
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Jim Pettit

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Re: 2019 sea ice area and extent data
« Reply #1182 on: June 15, 2019, 08:46:30 PM »
Doesn't 2018 show a similar rise in a few days time?

2018 had a two-day increase of 111k, but that was immediately preceded by a three-day decrease of 318k. This year's current 3-day increase of 160k is unequaled in June since at least 2000.

Hello Jim, so nice to meet you! Didn't know you are a forum member. Shame on me. ;)

I enjoyed and shared your data visualisations quite a lot. Great work!

Thanks! I've been mostly away from here for a bit dealing with life and other similar inconveniences. But it's all stable now, so I hope to be back more...

b_lumenkraft

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Re: 2019 sea ice area and extent data
« Reply #1183 on: June 15, 2019, 08:54:50 PM »
I'm glad to hear that Jim. :)

Welcome back then.

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Re: 2019 sea ice area and extent data
« Reply #1185 on: June 15, 2019, 10:13:40 PM »
For me, the image below illustrates another possible way extent might get greater while the ice is really melting like crazy.  (Remembering that extent includes any target area that contains at least 15% ice):

Large skeins and tendrils of disintegrating, melting ice extend from the main area of the floes and out into the ocean in this image.  You see these repeatedly at the edge of floe fields when melting is occurring.  If these skeins comprise greater than 15% ice (and visually they certainly seem to) then this might well result in a microwave measurement of greater extent, even while melting is proceeding apace.  If this happens all the way along an ice floe front, as it is now for this ice field, the numbers can add up.

The image is from Worldview from today from the ice that has exited the Fram Strait, and now lies on the east coast of Greenland.  This ice is now in direct sunshine and is also subject to warm winds and is taking a tremendous beating.

I am not suggesting this is the whole story (there is obviously much more) but this could be a factor in producing results that show greater extent even while it is logical to think the ice is melting rapidly.
« Last Edit: June 15, 2019, 10:20:18 PM by Pagophilus »

Pagophilus

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Re: 2019 sea ice area and extent data
« Reply #1186 on: June 15, 2019, 10:18:37 PM »
I am so good to you.

More than I deserve!  Thank you for the information and the learning.

Rich

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Re: 2019 sea ice area and extent data
« Reply #1187 on: June 15, 2019, 10:38:29 PM »
Area has declined 768k km2 in 5 days.

There's a decent chance that area will be declining in the next couple of days because there are (2) 200k+ days about to fall out of the average.

That said, the picture being presented by a variety of satellite images and the weather forecast is terrible. The dominoes are lined up to fall.

The Kara (wind and Atlantic intrusion) and Laptev (wind and heat) are going quickly.

ESS has the most heat but still some reserves of thick ice. It"s steadily moving toward open water to the 80N line.

Chuchki has warm SST's and ocean and also has some thicker ice. That warmth is going to win. Look forward to open water from Bering to Laptev by month end.

Beaufort showing small growth as the cyclonic spin is running counter to the gyre and spreading ice out. Warm water is intruding and the "arm" of old ice is slowly but steadily giving way. It won"t be as fast as the Laptev, but it's also marching to the 80N line.

Atlantic heat is moving into Baffin Bay and that could go pretty quick.

Hudson is just a matter of time.

That leaves the CAA and Central Basin in the hands of the summer weather gods. The southern and eastern CAA are melting at the moment.

The Central Basin has been through lots of insolation, steady but unspectacular warmth and thinned out by wind and export. It"s going to be a vulnerable summer.

The coming drop in extent will be epic.
« Last Edit: June 15, 2019, 10:43:33 PM by Rich »

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1188 on: June 15, 2019, 11:14:44 PM »
The image is from Worldview from today from the ice that has exited the Fram Strait, and now lies on the east coast of Greenland.  This ice is now in direct sunshine and is also subject to warm winds and is taking a tremendous beating.
To veer  from the vexed question of satellite measurement uncertainty.....

The Greenland Sea is really interesting this year. The graph attached shows that recently sea ice area has appeared to stall for some time, a great difference from say 2018. In that year the July August melt just did not happen (because ice in the main Arctic was not thinned by export through the Fram?).

But I don't think melt has stalled in 2019. It is a battle between import of ice from the Fram vs ongoing strong melt. Note that Greenland Sea ice area in 2012 was even higher and also very slow to reduce. This maybe suggests that there is a higher chance this year of higher melt in the main arctic ocean later in contrast to 2018.

Note also from the NSIDC sea ice concentration map  that although the sea ice extent of the northern half off Greenland's East coast is at the 1981-2010 average, the Southern half is almost ice-free and well below average. One wonders how much ice would survive in the Greenland Sea even as early as now if not for a continuous fresh supply of ice.
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uniquorn

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Re: 2019 sea ice area and extent data
« Reply #1189 on: June 15, 2019, 11:25:00 PM »
Doesn't 2018 show a similar rise in a few days time?
2018 had a two-day increase of 111k, but that was immediately preceded by a three-day decrease of 318k. This year's current 3-day increase of 160k is unequaled in June since at least 2000.
agreed. I just thought 2018 looked similar to 2019 at roughly this time of year
« Last Edit: June 15, 2019, 11:31:27 PM by uniquorn »

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Re: 2019 sea ice area and extent data
« Reply #1190 on: June 15, 2019, 11:34:55 PM »
Hi Gerontocrat .. would an open Nares make a difference when comparing 2019 with 2012 with regard to Fram export and  the current state of the Greenland sea ?
  The difference cannot be measured but may mean that your analysis underplays the potential for high Arctic melt this season .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

Sebastian Jones

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Re: 2019 sea ice area and extent data
« Reply #1191 on: June 15, 2019, 11:49:07 PM »
The image is from Worldview from today from the ice that has exited the Fram Strait, and now lies on the east coast of Greenland.  This ice is now in direct sunshine and is also subject to warm winds and is taking a tremendous beating.
To veer  from the vexed question of satellite measurement uncertainty.....

The Greenland Sea is really interesting this year. The graph attached shows that recently sea ice area has appeared to stall for some time, a great difference from say 2018. In that year the July August melt just did not happen (because ice in the main Arctic was not thinned by export through the Fram?).

But I don't think melt has stalled in 2019. It is a battle between import of ice from the Fram vs ongoing strong melt. Note that Greenland Sea ice area in 2012 was even higher and also very slow to reduce. This maybe suggests that there is a higher chance this year of higher melt in the main arctic ocean later in contrast to 2018.

Note also from the NSIDC sea ice concentration map  that although the sea ice extent of the northern half off Greenland's East coast is at the 1981-2010 average, the Southern half is almost ice-free and well below average. One wonders how much ice would survive in the Greenland Sea even as early as now if not for a continuous fresh supply of ice.

In 2012, I had only been seriously watching the Arctic ice melt for a few years, and had only begun to be aware of what the ice "should" look like. I am not sure I had even discovered this forum- I would follow the ice on the NOAA snow maps site. A feature of 2012 that really stuck out to me that summer was how much ice was in the Greenland Sea, and how far south it extended compared to the few years I remembered at that time. Once the Arctic ocean crashed later that summer, I wondered if there were a connection. As the years passed since then, the connection has become obvious to me- and to many others. If the arctic ice is flushed away to the Greenland, Arctic ice will be low, while extreme minima will be hard to reach if little ice goes to the Greenland sea. I have crappy analytic and arithmetic skills, and almost negative statistical skills, or I'd try to elucidate the connection. I'd start by picking a more or less random year as being 100% for the arctic ocean and the Greenland, and look at the extent of the Greenland at the start of summer- around now- compared to the Arctic at the end of summer. I'm pretty sure it would not be simple, and it might take some empirical testing to decide the best time to measure the Greenland. Maybe one day...
Anyway, 2019 seems to be bearing out this observation.

gerontocrat

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Re: 2019 sea ice area and extent data
« Reply #1192 on: June 16, 2019, 12:02:17 AM »
Hi Gerontocrat .. would an open Nares make a difference when comparing 2019 with 2012 with regard to Fram export and  the current state of the Greenland sea ?
  The difference cannot be measured but may mean that your analysis underplays the potential for high Arctic melt this season .. b.c.
As an avid reader of the Nares Strait thread I can only agree. Not only does it seem that the flow of ice down has been strong, it also seems that it has demonstrated that the ice going down its gullet from the Lincoln Sea has been in really poor shape.

But-- still over 60% of the melt to go.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Rich

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Re: 2019 sea ice area and extent data
« Reply #1193 on: June 16, 2019, 12:06:14 AM »
The image is from Worldview from today from the ice that has exited the Fram Strait, and now lies on the east coast of Greenland.  This ice is now in direct sunshine and is also subject to warm winds and is taking a tremendous beating.
One wonders how much ice would survive in the Greenland Sea even as early as now if not for a continuous fresh supply of ice.

Probably none. Outside of the ice coming down Fram and hugging the coast of Greenland, you've got warm water in the region.

Juan C. García

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Re: 2019 sea ice area and extent data
« Reply #1194 on: June 16, 2019, 05:41:57 AM »
I cannot access the ADS-NIPR (JAXA) page.  :-\
Can someone get the data?

Thanks!
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.

wdmn

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Re: 2019 sea ice area and extent data
« Reply #1195 on: June 16, 2019, 05:51:12 AM »
I cannot access the ADS-NIPR (JAXA) page.  :-\
Can someone get the data?

Thanks!

Not working for me either...

Pagophilus

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Re: 2019 sea ice area and extent data
« Reply #1196 on: June 16, 2019, 05:59:35 AM »

The Greenland Sea is really interesting this year. The graph attached shows that recently sea ice area has appeared to stall for some time, a great difference from say 2018. In that year the July August melt just did not happen (because ice in the main Arctic was not thinned by export through the Fram?).

But I don't think melt has stalled in 2019. It is a battle between import of ice from the Fram vs ongoing strong melt. Note that Greenland Sea ice area in 2012 was even higher and also very slow to reduce. This maybe suggests that there is a higher chance this year of higher melt in the main arctic ocean later in contrast to 2018.

In 2012, I had only been seriously watching the Arctic ice melt for a few years, and had only begun to be aware of what the ice "should" look like. I am not sure I had even discovered this forum- I would follow the ice on the NOAA snow maps site. A feature of 2012 that really stuck out to me that summer was how much ice was in the Greenland Sea, and how far south it extended compared to the few years I remembered at that time. Once the Arctic ocean crashed later that summer, I wondered if there were a connection. As the years passed since then, the connection has become obvious to me- and to many others. If the arctic ice is flushed away to the Greenland, Arctic ice will be low, while extreme minima will be hard to reach if little ice goes to the Greenland sea. I have crappy analytic and arithmetic skills, and almost negative statistical skills, or I'd try to elucidate the connection. I'd start by picking a more or less random year as being 100% for the arctic ocean and the Greenland, and look at the extent of the Greenland at the start of summer- around now- compared to the Arctic at the end of summer. I'm pretty sure it would not be simple, and it might take some empirical testing to decide the best time to measure the Greenland. Maybe one day...
Anyway, 2019 seems to be bearing out this observation.

First, the Greenland Sea graph is fascinating -- you almost hold your breath wondering if the Greenland Sea ice is going to take a dive as the corresponding 2012 ice did at this point.  Yes, I know that would be foolish because the amount of ice does not just depend on the amount of melting but also on the amount of Fram export in the next few weeks.   In fact, all that does matter is the amount of Fram export, since the Greenland Sea ice is future tense toast anyway.

Second, to S J's questioning about the a connection between arctic ice minima and the Greenland Sea ice extent/area, I would like to know the answers there also.  For me (I may be missing something), it is Fram export that is the crucial factor for the eventual state of the central Arctic basin, since that is more directly linked than the extent/area of Greenland Sea ice.  I found a relevant article online:
Fram Strait sea ice export variability and September Arctic sea ice extent over the last 80 years  Lars H. Smedsrud et al, in Cryosphere Discussions, 2 May 2016.   Link: https://www.the-cryosphere.net/11/65/2017/tc-2016-79.pdf

This post is already a mile long, so I won't quote their abstract, but in brief they mention no year on year correspondence of Fram export to arctic ice minima, so I assume they found none, but they do state: "We thus find that export anomalies during spring have a clear influence on the following September sea ice extent in general, and that for the recent decade, the export may be partially responsible for the accelerating decline in Arctic sea ice extent."

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Re: 2019 sea ice area and extent data
« Reply #1197 on: June 16, 2019, 10:27:35 AM »
JAXA is up again, but has no data for yesterday ...

pauldry600

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Re: 2019 sea ice area and extent data
« Reply #1198 on: June 16, 2019, 10:32:30 AM »
3 times in a row for the first time ever?

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Re: 2019 sea ice area and extent data
« Reply #1199 on: June 16, 2019, 10:39:17 AM »
.. it must be the 100k rise .. or is it a 300k fall ? .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...