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Wipneus

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Re: 2016 sea ice area and extent data
« Reply #400 on: June 16, 2016, 05:35:14 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.4493   +7.8  8.576390 +104.3 10.728776  +112.1 19.305166
Thu 2016.4521  -57.1  8.519276  +52.5 10.781309    -4.6 19.300585
Fri 2016.4548 -108.3  8.410998  +66.3 10.847582   -42.0 19.258580
Sat 2016.4575  -40.5  8.370483  +95.5 10.943110   +55.0 19.313593

Laptev and ESS bounced: +29k and +18k. The decline came from Hudson (-24k), CAA (-22k) and Baffin (-14k).

Shadow NSIDC extent is now 10.5707  a meager  -2.8k down. Bering and Barents went up (+22k and +18k). Baffin and Chukchi down (-18k both).

The attached delta map shows it all.

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #401 on: June 17, 2016, 05:14:55 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.4521  -57.1  8.519276  +52.5 10.781309    -4.6 19.300585
Fri 2016.4548 -108.3  8.410998  +66.3 10.847582   -42.0 19.258580
Sat 2016.4575  -40.7  8.370283  +95.9 10.943435   +55.1 19.313718
Sun 2016.4603 -135.3  8.234949 +107.0 11.050408   -28.4 19.285357

Area dropped big in CAB (-59k) and Hudson (-31k).

NSIDC extent is now 10.4419 a drop of -128.8k. Biggest declines in the Kara, Barents and Greenland Sea: -29k, -26k and -18k.

The attached delta map shows it all, in particular the decline of the ice around Svalbard.

Steven

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Re: 2016 sea ice area and extent data
« Reply #402 on: June 17, 2016, 05:24:06 PM »
Sun 2016.4603  ...  8.234949

At 8.23 million km2,  2016 remains second lowest for this date.  It is about 445k above the 2012 value for this date, and about 26k, 181k and 196k below the 2011, 2010 and 2007 values respectively for this date:


oren

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Re: 2016 sea ice area and extent data
« Reply #403 on: June 17, 2016, 05:43:41 PM »
The attached delta map shows it all, in particular the decline of the ice around Svalbard.

The ice-killing zone strikes back.

BornFromTheVoid

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Re: 2016 sea ice area and extent data
« Reply #404 on: June 17, 2016, 05:49:10 PM »
Even with that large extent drop, 2012 had dropped below 2016 with the daily values, knocking this year off lowest on record for the first time since April 17th

Rob Dekker

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Re: 2016 sea ice area and extent data
« Reply #405 on: June 18, 2016, 09:57:22 AM »
Hi Wipneus,
Since NSIDC does not publish daily "area" numbers, I'm trying to find a good analog.
Your "area" graph here seems a good start :
https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-area-all-cmpare.png

But which one should I use for NSIDC's "area" analog ?
There is the orange graph, but that one is labeled University Hamburg SSMIS 12.5 km.
There is one NSIDC graph (in blue) but that one is labeled NSIDC SSMIS 25 km 2015,
and I don't see the past graphs for that one.

So I guess I'm confused. Could you publish NSIDC's past and 2016 "area" numbers in a graph or (even better) in a table ?
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Wipneus

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Re: 2016 sea ice area and extent data
« Reply #406 on: June 18, 2016, 12:07:08 PM »
Rob,

My area numbers are in the same place as extent:

https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_nt_nrt_main.txt
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_nt_nrt_detail.txt

Like NSIDC the near-real-time data gets progressively replaced with "final" data. So the 1979-2015 data is here:

https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_nt_final_main.txt.gz
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_nt_final_detail.txt.gz

There is of course a whole lot of other data in that folder, like the 1981-2010 normals, Antarctic data and more.

Rob Dekker

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Re: 2016 sea ice area and extent data
« Reply #407 on: June 20, 2016, 03:22:41 AM »
Thanks Wipneus, and for the tremendous work you are doing. Especially this season, your work enabled many of us to stay focused on the data, which would not have been there without you.

Always looking forward to your daily updates here and in the home brew AMSR2 thread.

Now I just need to calibrate your 'area' numbers to the ones that NSIDC publishes once a month, and find a daily stream for snow cover, and I could turn my monthly SIPN projection model for September into a daily one.
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Wipneus

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Re: 2016 sea ice area and extent data
« Reply #408 on: June 20, 2016, 06:27:33 PM »
The NSIDC F18 gridded sea ice concentration data stream that was stopped for a few days has resumed. Let us see.

Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.4603 -135.2  8.235104 +107.0 11.050408   -28.2 19.285512
Mon 2016.4630 -125.5  8.109622  +86.3 11.136688   -39.2 19.246310
Tue 2016.4658  -94.8  8.014809 +118.5 11.255190   +23.7 19.269999
Wed 2016.4685 -107.9  7.906922 +156.7 11.411930   +48.9 19.318852

So there has been some strong concentration drops in the last few days. Regionally about everywhere but not in the ESS and Laptev.

The shadow NSIDC extent is now 10.2458, average drops in the last 4 days about -80k.

The delta map shows some heavy concentration drop in the Beaufort (might be unresolved open water in leads). The core of the central basin looks still white and cold.


Lord M Vader

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Re: 2016 sea ice area and extent data
« Reply #409 on: June 20, 2016, 06:46:16 PM »
Great job Wipneus! :) You, Espen, Neven, ASLR and many others are doing a tremendeous job.

How has the compactness rate evolved so far? Last I saw was a rather low value of compactness. Interesting to see whether extent numbers will go down by a century break as Hudson Bay (as well as Kara Sea) is "feeling the burn".

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #410 on: June 21, 2016, 02:23:39 PM »
ADS-NIPR Extent:
9,636,570 km2 (20 June)
Down 4,305,937 km2 (30.88%) from 2016 maximum of 13,942,507 km2 on 29 February.
6,459,115 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 94,616 km2 (-.97%) from previous day.
Down 464,067 km2  (-4.59%) over past seven days (daily average: -66,295 km2).
Down 790,474 km2  (-6.46%) for June (daily average: -39,524 km2).
994,222 km2 below 2000s average for this date.
358,238 km2 below 2010s average for this date.
450,395 km2 below 2015 value for this date.
169,199 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 20 June) average.
Lowest June to-date average.
Lowest value for the date.
117 days this year (68.42% year-to-date) have recorded the lowest daily extent.
27 days (15.79%) have recorded the second lowest.
14 days (8.19%) have recorded the third lowest.
158 days in total (92.4%) have been among the lowest three on record.


CT Area:
7,906,922 km2 (21 June [Day 0.4685])
Down 5,014,436 km2 (38.81%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
5,672,913 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 107,887 km2 (-1.35%) from previous day.
Down 669,468 km2 (-7.86%) over past seven days (daily average: -95,638 km2).
Down 1,524,132 km2 (-13.68%) for June (daily average: -72,578 km2).
863,838 km2 below 2000s average for this date.
199,990 km2 below 2010s average for this date.
262,042 km2 below 2015 value for this date.
168,662 km2 above 2012 value for this date.
2nd lowest value for the date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' area numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!


Wipneus

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Re: 2016 sea ice area and extent data
« Reply #411 on: June 21, 2016, 04:42:09 PM »
Double century extent drop!

But first here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Mon 2016.4630 -125.5  8.109622  +86.3 11.136688   -39.2 19.246310
Tue 2016.4658  -94.8  8.014809 +118.5 11.255190   +23.7 19.269999
Wed 2016.4685 -109.9  7.904862 +182.0 11.437148   +72.0 19.342010
Thu 2016.4712  -75.4  7.829501  +49.6 11.486738   -25.8 19.316239

Kara had a big drop (-44k). ESS and Laptev seem to have exchanged ice area (-25k and +25k)
Shadow NSIDC extent is 10.0288 a drop of -210.4k. Also here Kara is the leader (-69k), but Okhotsk (-38k), Hudson (-30k) and Baffin (-27k) declined lots too.

The delta image shows in bright red colors where extent went down. Some of it is coastal ice like in Okhotsk but in other places (Kara, Hudson) the decline looks genuine.

Steven

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Re: 2016 sea ice area and extent data
« Reply #412 on: June 21, 2016, 05:15:46 PM »
here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

Thu 2016.4712  ...  7.829501

At 7.829 million km2,  2016 is now in third place.  It is about 242k and 85k above the 2012 and 2007 values respectively for this date, and about 55k and 148k below the 2010 and 2011 values respectively:



BornFromTheVoid

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Re: 2016 sea ice area and extent data
« Reply #413 on: June 21, 2016, 07:54:47 PM »
Update for the week to June 18th

The current 5 day trailing average is on 10,452,000km2 while the 1 day extent is at 10,337,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,332,000km2, an increase from -1,309,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -395,000km2, a decrease from -610,000km2 last week. We're currently the lowest on record, the same as last week.



The average daily change over the last 7 days was -51.3k/day, compared to the long term average of -48.0k/day, and the 07, 11 and 12 average of -82.1k/day.
The average long term change over the next week is -59.7k/day, with the 07, 11, and 12 average being -78.9k/day.



The extent drop so far this June is the 5th smallest on record. To achieve the largest monthly loss, a drop of at least 180.5k/day is required (requiring >204.9k/day with with single day values), while the smallest loss requires a drop less than 38.0k/day (<22.0k/day with single day values) and an average loss requires a drop of 78.3k/day (~82.4k/day with single day values).


DavidR

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Re: 2016 sea ice area and extent data
« Reply #414 on: June 21, 2016, 11:20:39 PM »
NSIDC reports a 210 K extent drop for the 20th with the figure for the 19th  revised downward.
2016   6   19   10.239
2016   6   20   10.029

That makes a drop of almost 550K in the past 5 days and puts extent over 100K in front  again.
« Last Edit: June 21, 2016, 11:56:10 PM by DavidR »
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Wipneus

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Re: 2016 sea ice area and extent data
« Reply #415 on: June 22, 2016, 04:22:05 PM »
The effects of the arctic low are visible in the concentration numbers.

Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Tue 2016.4658  -94.8  8.014809 +118.5 11.255190   +23.7 19.269999
Wed 2016.4685 -109.9  7.904862 +182.0 11.437148   +72.0 19.342010
Thu 2016.4712  -75.1  7.829714  +50.4 11.487504   -24.8 19.317218
Fri 2016.4740 -143.5  7.686262  -40.2 11.447313  -183.6 19.133575

That is Laptev (-64k) and CAB (-48k) doing the work.

Shadow NSIDC ended at 10.0219   only dropping -6.4k. Kara got a big correction (+46k), Beaufort in creased +17k. Declining are Greenland Sea (-35k), Baffin (-17k) and Barents (-16k).

The delta map should tell you the rest.

Shared Humanity

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Re: 2016 sea ice area and extent data
« Reply #416 on: June 22, 2016, 07:33:45 PM »
Looking at the concentration image, what I find amazing is how a relatively weak cyclone can wreak such havoc in the central CAB in such a short space of time. It really does support how the ice is no longer the ice of a decade ago. It is very mobile and very broken up.

slow wing

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Re: 2016 sea ice area and extent data
« Reply #417 on: June 23, 2016, 12:39:50 AM »
Some/most/all of that crimson in the Laptev Sea and CAB could be rain fallen on the ice where the storm went?

It will be interesting to see in the visible when the clouds clear.

Note there is no change in the Chukchi Sea where the ice already shows as grey for reduced concentration, e.g. around 180 degrees longitude, 78 degrees latitude where holes are showing in an EOSDIS screenshot posted by jdallen on the 2016 Melting Season thread:
http://forum.arctic-sea-ice.net/index.php/topic,1493.msg81055.html#msg81055.
It looks like the storm winds might have made some of the tears more obvious though.
« Last Edit: June 23, 2016, 12:47:00 AM by slow wing »

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #418 on: June 23, 2016, 04:31:28 PM »
Area keeps dropping making good speed.

Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:
day  CT-date       NH               SH                Global
Wed 2016.4685 -109.9  7.904862 +182.0 11.437148   +72.0 19.342010
Thu 2016.4712  -75.1  7.829714  +50.3 11.487430   -24.9 19.317144
Fri 2016.4740 -137.3  7.692412  -36.4 11.451015  -173.7 19.143427
Sat 2016.4767 -174.0  7.518434  +52.2 11.503208  -121.8 19.021642

CAB (-79k), ESS (-35k) and Chukchi (-31k) are the heavy lifters here. The CAA increased area by +24k.

Shadow NSIDC ended at 10.4544 a drop of -153.8k. Kara (-38k), Hudson (-30k), Barents (-24k) and Chukchi (-22k) declined most.
Shadow NSIDC extent ended at 9957.2  a drop of -57.7k. Kara (-31k), Hudson (-31k) and Chukchi (-17k) declined most.

The attached delta map  shows where the damage is done. Or just a wet surface after rain of course.
« Last Edit: June 23, 2016, 05:46:32 PM by Wipneus »

BornFromTheVoid

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Re: 2016 sea ice area and extent data
« Reply #419 on: June 23, 2016, 05:25:14 PM »
Area keeps dropping making good speed.

Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:
day  CT-date       NH               SH                Global
Wed 2016.4685 -109.9  7.904862 +182.0 11.437148   +72.0 19.342010
Thu 2016.4712  -75.1  7.829714  +50.3 11.487430   -24.9 19.317144
Fri 2016.4740 -137.3  7.692412  -36.4 11.451015  -173.7 19.143427
Sat 2016.4767 -174.0  7.518434  +52.2 11.503208  -121.8 19.021642

CAB (-79k), ESS (-35k) and Chukchi (-31k) are the heavy lifters here. The CAA increased area by +24k.

Shadow NSIDC ended at 10.4544 a drop of -153.8k. Kara (-38k), Hudson (-30k), Barents (-24k) and Chukchi (-22k) declined most.

The attached delta map  shows where the damage is done. Or just a wet surface after rain of course.

Something seems a little off, Wipneus.

The shadow NSIDC was at 10.0219 on yesterdays update, but 10.4544 today?

be cause

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Re: 2016 sea ice area and extent data
« Reply #420 on: June 23, 2016, 05:45:05 PM »
A shadow CT area fall of over 850 000 sq km in 7 days and over 1 million in the last 10 .
Maintaining similar losses would leave an ice -free Arctic before the end of the melt season . At the rate of losses of the last 2 days we would have no ice to follow in only 25 days !
I am not expecting ice-free but most certainly a major North Pole Hole seems very likely and very news worthy when it happens ..
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 ...

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #421 on: June 23, 2016, 05:48:57 PM »

Something seems a little off, Wipneus.

The shadow NSIDC was at 10.0219 on yesterdays update, but 10.4544 today?

More than a little BFTV. I was reading from the wrong file, thanks for catching this.

oren

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Re: 2016 sea ice area and extent data
« Reply #422 on: June 23, 2016, 08:24:32 PM »
A shadow CT area fall of over 850 000 sq km in 7 days and over 1 million in the last 10 .
Maintaining similar losses would leave an ice -free Arctic before the end of the melt season . At the rate of losses of the last 2 days we would have no ice to follow in only 25 days !
I am not expecting ice-free but most certainly a major North Pole Hole seems very likely and very news worthy when it happens ..

As we have seen recently, these large area drops in the middle of the pack do not mean the ice is gone, just that its top is wet/ponded. In a couple of days some of these drops might be reversed. Of course the ice has suffered in the meantime, but still it's risky to simply extrapolate these numbers.

CameraMan

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Re: 2016 sea ice area and extent data
« Reply #423 on: June 23, 2016, 10:41:48 PM »
As we have seen recently, these large area drops in the middle of the pack do not mean the ice is gone, just that its top is wet/ponded. In a couple of days some of these drops might be reversed.

Look at today's satellite photos.  Those aren't just melt ponds.  The ice is broken up with patches of open water.  It's not gone, but not looking healthy.

bbr2314

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Re: 2016 sea ice area and extent data
« Reply #424 on: June 23, 2016, 11:48:42 PM »
A shadow CT area fall of over 850 000 sq km in 7 days and over 1 million in the last 10 .
Maintaining similar losses would leave an ice -free Arctic before the end of the melt season . At the rate of losses of the last 2 days we would have no ice to follow in only 25 days !
I am not expecting ice-free but most certainly a major North Pole Hole seems very likely and very news worthy when it happens ..

As we have seen recently, these large area drops in the middle of the pack do not mean the ice is gone, just that its top is wet/ponded. In a couple of days some of these drops might be reversed. Of course the ice has suffered in the meantime, but still it's risky to simply extrapolate these numbers.
...idk how people are confusing the gaping fissures that span from Siberia to Canada with melt ponds but it seems like half the people here have blinders on to what is ongoing.

I know HYCOM gets a lot of flak but instead of projecting out, let's look at the last five days.





The ice has clearly broken completely in two now, and the recent ~970mb low did a major whomping to the ice in the "cleavage" between what's stuck against Siberia and the main CAB.

If we are talking about a potentially ice-free Arctic, you would want to see the thickest ice pushed up against areas collecting massive amounts of heat... exactly like what's occurring in the Beaufort.

Things are bleak and getting worse, the entire Siberian side is now giving out. I would not be surprised to see a 200K+ area drop soon, and sustained 100K+ daily drops (or at least averaging out to 100K+) for foreseeable future.

DMI shows surface temps skyrocketing in peripheral seas, Beaufort about to break 10C in spots.


Laurent

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Re: 2016 sea ice area and extent data
« Reply #425 on: June 24, 2016, 11:58:18 AM »
Personally, I think Hycom is good for the forecast but for the reality of the situation direct vision with normal RVB image is better (modis/worldview). For example, Hycom say there is still integrity along the path from Laptev to Beaufort when direct observation show none, that's because they have some difficulty with small flows (also it is designed for ship navigation, so it looks for the worse).

Beaufort big chunks are disintegrating.
http://go.nasa.gov/291w2XV

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #426 on: June 24, 2016, 04:28:36 PM »
Area is recovering (drying up) from the effects of the arctic low.

Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.4712  -75.1  7.829714  +50.3 11.487430   -24.9 19.317144
Fri 2016.4740 -137.3  7.692412  -36.4 11.451015  -173.7 19.143427
Sat 2016.4767 -173.7  7.518684  +51.9 11.502902  -121.8 19.021586
Sun 2016.4795  -16.2  7.502533  +24.3 11.527170    +8.1 19.029703

That "recovery" was in the CAB (+38k) and Laptev (+31k). Chukchi (-34k) and Hudson (-31k) continue to decline strongly.
Shadow NSIDC extent is now  9.8927 a drop of  -65.1k. Barents and Beaufort both increased by +21k.  Hudson, Baffin, Kara and Chukchi declined (-32k, -27k, -23k and -22k).

The attached delta image should tell you the rest.
 

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #427 on: June 25, 2016, 02:47:20 PM »
ADS-NIPR (IJIS) Extent:
9,331,851 km2 (24 June)
Down 4,610,656 km2 (33.07%) from 2016 maximum of 13,942,507 km2 on 29 February.
6,154,396 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 93,778 km2 (-.99%) from previous day.
Down 538,872 km2  (-5.46%) over past seven days (daily average: -76,982 km2).
Down 1,095,193 km2  (-8.95%) for June (daily average: -45,633 km2).
1,018,402 km2 below 2000s average for this date.
366,591 km2 below 2010s average for this date.
584,955 km2 below 2015 value for this date.
229,431 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 24 June) average.
Lowest June to-date average.
Lowest value for the date.
121 days this year (69.14% year-to-date) have recorded the lowest daily extent.
27 days (15.43%) have recorded the second lowest.
14 days (8.%) have recorded the third lowest.
162 days in total (92.57%) have been among the lowest three on record.


CT Area:
7,502,533 km2 (25 June [Day 0.4795])
Down 5,418,825 km2 (41.94%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
5,268,524 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 16,151 km2 (-.21%) from previous day.
Down 732,571 km2 (-9.03%) over past seven days (daily average: -104,653 km2).
Down 1,928,521 km2 (-17.32%) for June (daily average: -77,141 km2).
887,920 km2 below 2000s average for this date.
253,103 km2 below 2010s average for this date.
454,608 km2 below 2015 value for this date.
131,304 km2 above 2012 value for this date.
3rd lowest value for the date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' area numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #428 on: June 25, 2016, 04:37:59 PM »
Century extent drop. Area takes it slow.

Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Fri 2016.4740 -137.3  7.692412  -36.4 11.451015  -173.7 19.143427
Sat 2016.4767 -173.7  7.518684  +51.9 11.502902  -121.8 19.021586
Sun 2016.4795  -16.1  7.502592  +24.3 11.527170    +8.2 19.029762
Mon 2016.4822  -27.3  7.475246  +12.0 11.539198   -15.3 19.014444


CAB increased by +35k, Kara and Beaufort declined -17k each.

Shadow NSIDC extent is now 9.7719 a drop of -120.8k. Also here it happened in Kara (-33k) and Beaufort (-25k).

I let the attached delta map speak for itself.


Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #429 on: June 25, 2016, 04:53:23 PM »
Century extent drop. Area takes it slow.

Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Fri 2016.4740 -137.3  7.692412  -36.4 11.451015  -173.7 19.143427
Sat 2016.4767 -173.7  7.518684  +51.9 11.502902  -121.8 19.021586
Sun 2016.4795  -16.1  7.502592  +24.3 11.527170    +8.2 19.029762
Mon 2016.4822  -27.3  7.475246  +12.0 11.539198   -15.3 19.014444

And just like that, SIA drops back to 4th place (behind 2010, 2012, and 2007), and out of the top three for the first time since March. And with both 2007 and 2012 losing around a million km2 over the next eight-day stretch, 2016 will have to really turn on the heat to stay close to the front of the pack.
« Last Edit: June 25, 2016, 05:05:10 PM by Jim Pettit »

CIP

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Re: 2016 sea ice area and extent data
« Reply #430 on: June 25, 2016, 07:34:41 PM »
Anyone care to comment on the apparent divergence between AMSR2 and NSDIC.

Neven

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Re: 2016 sea ice area and extent data
« Reply #431 on: June 25, 2016, 08:54:11 PM »
Century extent drop. Area takes it slow.

Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Fri 2016.4740 -137.3  7.692412  -36.4 11.451015  -173.7 19.143427
Sat 2016.4767 -173.7  7.518684  +51.9 11.502902  -121.8 19.021586
Sun 2016.4795  -16.1  7.502592  +24.3 11.527170    +8.2 19.029762
Mon 2016.4822  -27.3  7.475246  +12.0 11.539198   -15.3 19.014444

And just like that, SIA drops back to 4th place (behind 2010, 2012, and 2007), and out of the top three for the first time since March. And with both 2007 and 2012 losing around a million km2 over the next eight-day stretch, 2016 will have to really turn on the heat to stay close to the front of the pack.

Jim, don't you mean 3rd place? According to my spreadsheet 2016 is currently around 98K lower than 2007. Or did you mean 2006 (which isn't part of my spreadsheet)?
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Nick_Naylor

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Re: 2016 sea ice area and extent data
« Reply #432 on: June 25, 2016, 10:11:17 PM »
Since 2016 is a leap year, it depends on whether you're comparing by date, or by day of the year.

2007.4795  -1.5666438   7.5740676   9.1407118 (same date)
2007.4822  -1.5840672   7.4571447   9.0412121 (same day number)

Neither method is 100% "fair" . . .

Neven

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Re: 2016 sea ice area and extent data
« Reply #433 on: June 26, 2016, 12:31:29 AM »
You're right, I did look at next day number for 2007, but didn't do it carefully enough.
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RoxTheGeologist

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Re: 2016 sea ice area and extent data
« Reply #434 on: June 26, 2016, 02:14:02 AM »
Since 2016 is a leap year, it depends on whether you're comparing by date, or by day of the year.

2007.4795  -1.5666438   7.5740676   9.1407118 (same date)
2007.4822  -1.5840672   7.4571447   9.0412121 (same day number)

Neither method is 100% "fair" . . .

Ideally the azimuth to the sun from the pole at midday would be the most "correct" method.. perhaps a small adjustment up or down of daily data would give a more accurate comparison; essentially mapping the discrete data to the continuous.

plinius

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Re: 2016 sea ice area and extent data
« Reply #435 on: June 26, 2016, 12:00:02 PM »
Simple solution would be to just give each year 365.25 days in the data and ignore human counting. Solution  would then be to have all years just plotted on this running scale (which shifts days by 0.25 pixels every year) and accept that only every fourth year matches up (quite) exactly. Anyway not a big deal to figure in that one day difference is about -80k km^2 at the moment, so a quarter day is 0.2/

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Re: 2016 sea ice area and extent data
« Reply #436 on: June 26, 2016, 04:42:04 PM »
Both area and extent are in the fast lane now.

Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.4767 -173.7  7.518684  +51.9 11.502902  -121.8 19.021586
Sun 2016.4795  -16.1  7.502592  +24.3 11.527170    +8.2 19.029762
Mon 2016.4822  -26.6  7.475945  +12.1 11.539295   -14.5 19.015240
Tue 2016.4849 -169.8  7.306147  -11.7 11.527598  -181.5 18.833745

Biggest contributors are CAB (-56k), ESS (-26k) and Kara (-25k).

Shadow NSIDC extent is 9.6475 dropping -124.4k. Here Kara (-67k) and Hudson (-38k)  decline most.

The attached delta map will illustrate the numbers.

Steven

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Re: 2016 sea ice area and extent data
« Reply #437 on: June 26, 2016, 04:59:51 PM »
Tue 2016.4849  ...  7.306147

Back in 3rd place, behind 2010 and 2012:



Wipneus

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Re: 2016 sea ice area and extent data
« Reply #438 on: June 27, 2016, 04:59:00 PM »
A bump in extent and a large drop of area in the CAB.

Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.4795  -16.1  7.502592  +24.3 11.527170    +8.2 19.029762
Mon 2016.4822  -26.6  7.475945  +12.1 11.539295   -14.5 19.015240
Tue 2016.4849 -169.8  7.306130  -11.7 11.527548  -181.6 18.833678
Wed 2016.4877  -48.2  7.257883  +45.9 11.573427    -2.4 18.831310

The drop in area can be almost completely explained by the CAB: -47k. No significant changes in the other regions.

Shadow NSIDC extent is now at 9.6726  an increase of +25.1k. That is mostly from Kara (+26k) and Greenland Sea (+13k).

Judging from the atached delta map I think this is ice hovering around the 15% concentration. The concentration drops in the CAB are in a range from the Canadian islands to Svalbard.

abbottisgone

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Re: 2016 sea ice area and extent data
« Reply #439 on: June 28, 2016, 03:55:43 AM »
Since 2016 is a leap year, it depends on whether you're comparing by date, or by day of the year.

2007.4795  -1.5666438   7.5740676   9.1407118 (same date)
2007.4822  -1.5840672   7.4571447   9.0412121 (same day number)

Neither method is 100% "fair" . . .
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Wipneus

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Re: 2016 sea ice area and extent data
« Reply #440 on: June 28, 2016, 04:48:09 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Mon 2016.4822  -26.6  7.475945  +12.1 11.539295   -14.5 19.015240
Tue 2016.4849 -169.8  7.306130  -11.7 11.527548  -181.6 18.833678
Wed 2016.4877  -48.2  7.257883  +45.9 11.573422    -2.4 18.831305
Thu 2016.4904  -93.4  7.164501 +115.7 11.689137   +22.3 18.853638

Hudson (-37k) and CAB (-20k) did most of that.

Shadow NSIDC extent is 9.5429 dropping -129.6k. It seems to be the time of the Hudson cliff (-42k). Baffin (-22k) and Barents (-21k) follow at a distance.

The attached delta map shows many details.

BornFromTheVoid

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Re: 2016 sea ice area and extent data
« Reply #441 on: June 28, 2016, 05:56:38 PM »
Update for the week to June 25th

The current 5 day trailing average is on 9,858,000km2 while the 1 day extent is at 9,647,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,509,000km2, an increase from -1,332,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -437,000km2, an increase from -395,000km2 last week. We're currently the lowest on record, the same as last week.



The average daily change over the last 7 days was -84.9k/day, compared to the long term average of -59.7k/day, and the 07, 11 and 12 average of -78.9k/day.
The average long term change over the next week is -74.1k/day, with the 07, 11, and 12 average being -108.4k/day.



The extent drop so far this June is the 18th largest on record. To achieve the largest monthly loss, a drop of at least 314.1k/day is required (requiring >453.0k/day with with single day values), while the smallest loss requires an increase of at least 51.8k/day (>156.5k/day with single day values) and an average loss requires a drop of 69.0k/day (~44.6k/day with single day values).


Wipneus

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Re: 2016 sea ice area and extent data
« Reply #442 on: June 29, 2016, 08:27:16 AM »
I found this in my inbox this morning:

Quote
NOAA@NSIDC to Release Sea Ice Index Version 2 Next Week
June 28, 2016   

An improved version of the Sea Ice Index is coming.  On Wednesday, 6 July 2016, Sea Ice Index Version 2 will be released. It will look and act the same as Version 1, but will have updated processing code and will use a new version of the input data. Because of these updates, minor changes in some of the ice extent and area numbers will be seen. These will be clearly described in the documentation, which will also be updated on 6 July.

We are alerting users to this impending update because file names will change. Any scripts that automatically download Sea Ice Index data each day will need to be updated to reflect this file name change. The new file names will have a “_v2” appended to the end of the file name such as N_04_area_v2.txt and N_04_plot_v2.png.

See http://nsidc.org/the-drift/data-update/noaansidc-to-release-sea-ice-index-version-2-next-week/

Now I don't know anything about "updated processing code" or "a new version of the input data", so I have to wait until further details are known. It could be very significant, eg if the new code does a better job at removing false coastal ice.
 

Neven

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Re: 2016 sea ice area and extent data
« Reply #443 on: June 29, 2016, 09:52:22 AM »
That's interesting. Thanks, Wipneus.
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Re: 2016 sea ice area and extent data
« Reply #444 on: June 29, 2016, 10:20:08 AM »

Quote
It could be very significant, eg if the new code does a better job at removing false coastal ice.

I doubt this. But I heard that OSI SAF have implemented the method of Maaß and Kaleschke (2010). However, not sure if it is already in their operational product.

Maaß, N., L. Kaleschke, Improving passive microwave sea ice concentration algorithms for coastal areas - Applications to the Baltic Sea, Tellus A, Volume 62, Issue 4, Pages: 393–410, 2010

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #445 on: June 29, 2016, 05:21:47 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Tue 2016.4849 -169.8  7.306130  -11.7 11.527548  -181.6 18.833678
Wed 2016.4877  -48.2  7.257883  +45.9 11.573422    -2.4 18.831305
Thu 2016.4904  -93.3  7.164613 +115.8 11.689271   +22.6 18.853884
Fri 2016.4932  -70.4  7.094193 +116.9 11.806130   +46.4 18.900323

Hudson saw a big drop (-48k), interesting because the UH ASI data (based on AMSR2 satellite data) saw an big increase there. Similar shadow CT-area Chukchi declines -31k, where the AMSR2 based area grew a small amount.

Shadow NSIDC extent was 9.4885 a drop of -53.8k. Kara, Chukchi and Hudson declined -38k, -24k and -19k. Beaufort increased by +22k.

The attached delta map illustrates the numbers.

BornFromTheVoid

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Re: 2016 sea ice area and extent data
« Reply #446 on: June 29, 2016, 05:42:13 PM »
The 5 day trailing average, used for the NSIDC sea ice index, is now 2nd lowest - above 2010.
The is the first time since April 18th and it hasn't been lowest on record.

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Re: 2016 sea ice area and extent data
« Reply #447 on: June 30, 2016, 03:58:36 PM »
Single day NSIDC extent is now 215k above 2010 and 53k above 2012

Wipneus

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Re: 2016 sea ice area and extent data
« Reply #448 on: June 30, 2016, 04:23:39 PM »
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.4877  -48.2  7.257883  +45.9 11.573422    -2.4 18.831305
Thu 2016.4904  -93.3  7.164613 +115.8 11.689271   +22.6 18.853884
Fri 2016.4932  -70.3  7.094268 +117.1 11.806354   +46.7 18.900622
Sat 2016.4959  -44.6  7.049632  +90.5 11.896885   +45.9 18.946517

CAB is not cooperating: +30k. Beaufort, Hudson and Kara declined -23k, -22k and -15k.

Shadow NSIDC extent is 9.4463 dropping -42.2k. Hudson, Baffin and Beaufort dropped -24k, -23k and -15k.

Attached delta map should tell you the rest.

Jim Pettit

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Re: 2016 sea ice area and extent data
« Reply #449 on: July 01, 2016, 01:57:45 PM »
ADS-NIPR Extent:
8,973,708 km2 (30 June)
Down 4,968,799 km2 (35.64%) from 2016 maximum of 13,942,507 km2 on 29 February.
5,796,253 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 60,021 km2 (-.66%) from previous day.
Down 451,921 km2  (-4.79%) over past seven days (daily average: -64,560 km2).
Down 1,453,336 km2  (-11.88%) for June (daily average: -48,445 km2).
932,493 km2 below 2000s average for this date.
189,709 km2 below 2010s average for this date.
508,608 km2 below 2015 value for this date.
66,203 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 30 June) average.
Lowest June average.
2nd lowest value for the date.
124 days this year (68.51% year-to-date) have recorded the lowest daily extent.
30 days (16.57%) have recorded the second lowest.
14 days (7.73%) have recorded the third lowest.
168 days in total (92.82%) have been among the lowest three on record.


CT Area:
7,049,632 km2 (01 July [Day 0.4958])
Down 5,871,726 km2 (45.44%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
4,815,623 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 44,636 km2 (-.63%) from previous day.
Down 469,052 km2 (-6.25%) over past seven days (daily average: -67,007 km2).
Down 44,636 km2 (-.4%) for July (daily average: -44,636 km2).
707,717 km2 below 2000s average for this date.
71,009 km2 below 2010s average for this date.
370,134 km2 below 2015 value for this date.
436,899 km2 above 2012 value for this date.
4th lowest value for the date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' area numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!