Arctic Sea Ice : Forum

Cryosphere => Arctic sea ice => Topic started by: Neven on January 03, 2017, 01:14:06 PM

Title: 2017 sea ice area and extent data
Post by: Neven on January 03, 2017, 01:14:06 PM
Someone told me a new year has started, so here's a new thread to replace the 2016 version (http://forum.arctic-sea-ice.net/index.php/topic,1457.0.html).

Have at it, spread the data.
Title: Re: 2017 sea ice area and extent data
Post by: Buddy on January 03, 2017, 03:44:29 PM
Two areas I'll be watching come March/April/May:

1)  Beaufort on the Pacific side
2)  The 3 Archipelago's on the Atlantic side:  (a) Svalbard (b) Franz Joseph (c)  Severnaya Zemlya (just off the north Russian coast.....next to Franz Joseph)

Those 3 archipelago's + NE Greenland provide a "line of protection" for the sea ice.  Svalbard has been hammered over the past year, so that has already been eaten away.....and I expect the channels between the other two archipelago's to be hammered this coming spring/summer/fall.

Will be interesting to see if a "squeeze" develops on the sea ice this summer between the two advancing fronts of warm water from the Pacific and Atlantic sides.....  My main curiosity will be to see how quickly the Atlantic side melting can be advanced in the spring and early summer.   Can it be "softened up" enough....so that when we get to "serious melting" in June/July/August.....that a large bite can be taken out of the sea ice and move to a significant new record low.

 

Title: Re: 2017 sea ice area and extent data
Post by: jdallen on January 03, 2017, 05:58:29 PM
Two areas I'll be watching come March/April/May:

1)  Beaufort on the Pacific side
2)  The 3 Archipelago's on the Atlantic side:  (a) Svalbard (b) Franz Joseph (c)  Severnaya Zemlya (just off the north Russian coast.....next to Franz Joseph)

Those 3 archipelago's + NE Greenland provide a "line of protection" for the sea ice.  Svalbard has been hammered over the past year, so that has already been eaten away.....and I expect the channels between the other two archipelago's to be hammered this coming spring/summer/fall.

Will be interesting to see if a "squeeze" develops on the sea ice this summer between the two advancing fronts of warm water from the Pacific and Atlantic sides.....  My main curiosity will be to see how quickly the Atlantic side melting can be advanced in the spring and early summer.   Can it be "softened up" enough....so that when we get to "serious melting" in June/July/August.....that a large bite can be taken out of the sea ice and move to a significant new record low.

 

As will I and concur; the open water in the Barents and around Svalbard is already dangerous.  That much open water north of 70 degrees latitude is a huge heat trap, and unlike in the past when it was covered with ice, will start the capture just as soon as the sun starts to reappear there in a few weeks.  That represents "free heat" for the melt season, even before it starts in earnest.
Title: Re: 2017 sea ice area and extent data
Post by: seaicesailor on January 03, 2017, 07:47:58 PM
Two areas I'll be watching come March/April/May:

1)  Beaufort on the Pacific side
2)  The 3 Archipelago's on the Atlantic side:  (a) Svalbard (b) Franz Joseph (c)  Severnaya Zemlya (just off the north Russian coast.....next to Franz Joseph)

Those 3 archipelago's + NE Greenland provide a "line of protection" for the sea ice.  Svalbard has been hammered over the past year, so that has already been eaten away.....and I expect the channels between the other two archipelago's to be hammered this coming spring/summer/fall.

Will be interesting to see if a "squeeze" develops on the sea ice this summer between the two advancing fronts of warm water from the Pacific and Atlantic sides.....  My main curiosity will be to see how quickly the Atlantic side melting can be advanced in the spring and early summer.   Can it be "softened up" enough....so that when we get to "serious melting" in June/July/August.....that a large bite can be taken out of the sea ice and move to a significant new record low.

 

As will I and concur; the open water in the Barents and around Svalbard is already dangerous.  That much open water north of 70 degrees latitude is a huge heat trap, and unlike in the past when it was covered with ice, will start the capture just as soon as the sun starts to reappear there in a few weeks.  That represents "free heat" for the melt season, even before it starts in earnest.

Just a note that in 2014 Svalbard was free of ice in Feb/March but then cold weather pushed the ice well into Barents where it did not melt until October or November... we never know
Title: Re: 2017 sea ice area and extent data
Post by: Tor Bejnar on January 03, 2017, 08:47:47 PM
The general flow of floes in the Arctic is toward the Canadian Arctic and Atlantic (even considering the Beaufort Gyre), so that if the ice front on the Atlantic side remained fairly stable this coming NH spring, I would expect catastrophe on the Pacific or Siberian sides, because the Atlantic side would be constantly replenished.  I think this is more likely than the reverse (stable Pacific side with early ice retreat on the Atlantic side), even with the Atlantic as warm as it is.  Given how mobile and thin this sea ice is thus far, I won't be surprised to see early retreats from all the non-Canadian & non-Greenland border areas.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on January 04, 2017, 08:35:06 AM
Thanks Neven for a place where we can discuss the data.

I take the liberty to report global data here as well.

The first 2017 data is starting to appear in the graph. As we are heading for February when the annual minimum of global sea ice area and extent is to be expected (from experience in the past 38 years at least) we can have a look at our heading.

Both area and extent are still well below anything else in the data set, making new records likely. Extent is still above the annual minimum of many years, but area is nearing the lowest level ever quickly. Current global sea ice area is 14.253 Mm2, 2006 and 2016 annual minimums were 14.196 and 13.961  Mm2.

I have assembled a global sea ice page here:
https://sites.google.com/site/arctischepinguin/home/global-sea-ice

Attaching the global area and extent, as well as global sea ice volume, modeled by GIOMAS. The volume graph basically tells the same story as the other two.
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on January 04, 2017, 01:46:10 PM
(Apologies for the delay, Christmas and travelling...)

Update for the week to December 31st

The current 5 day trailing average is on 12,506,000km2 while the 1 day extent is at 12,608,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,042,000km2, a decrease from -1,372,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -434,000km2, a decrease from -645,000km2 last week. We're currently 2nd lowest on record, down from lowest last week.

(http://i.imgur.com/HkKsjcC.png)

The average daily change over the last 7 days was +91.4k/day, compared to the long term average of +44.2k/day, and the 07, 11 and 12 average of +61.2k/day.
The average long term change over the next week is +64.7k/day, with the 07, 11, and 12 average being +49.5k/day.

(http://i.imgur.com/1Auf4oS.png)

The extent increase in December was the 2nd largest on record while the average extent was the lowest on record.

(http://i.imgur.com/mPaGtCx.png)

(http://i.imgur.com/91wynEg.png)
Title: Re: 2017 sea ice area and extent data
Post by: Buddy on January 04, 2017, 02:16:21 PM
I have assembled a global sea ice page here:
https://sites.google.com/site/arctischepinguin/home/global-sea-ice

Sweet...as always.

Wipneus....on your GIOMAS chart....did the first half of January and the second half of December get deleted or "left behind" some how?  LOVE the volume chart....just curious about the last half of December.

Thanks....
Title: Re: 2017 sea ice area and extent data
Post by: crandles on January 04, 2017, 02:28:39 PM
just curious about the last half of December.

Think there is just one data point for each month shown in the middle of that month. It might be better with a straight line extrapolation for the two half months between the dec and jan data points but could be awkward to graph that without appearing to have 14 data points in the year.
Title: Re: 2017 sea ice area and extent data
Post by: Buddy on January 04, 2017, 02:33:43 PM
Think there is just one data point for each month shown in the middle of that month

Got it.  Thanks....
Title: Re: 2017 sea ice area and extent data
Post by: Pmt111500 on January 04, 2017, 02:44:40 PM
just curious about the last half of December.

Think there is just one data point for each month shown in the middle of that month. It might be better with a straight line extrapolation for the two half months between the dec and jan data points but could be awkward to graph that without appearing to have 14 data points in the year.
plus would be impossible to do that properly before february.
Title: Re: 2017 sea ice area and extent data
Post by: Buddy on January 04, 2017, 02:59:23 PM
That GIOMAS chart by Wipneus shows a rather "startling" figure:

Global sea ice VOLUME is 15% below the prior record low volume.  I probably don't have to tell most of you this....but 15% of VOLUME IS A LOT.

NOTE:  23.25 vs 27.5 = 15% drop

Addendum:

I'll let the mathematics and science experts wrestle with the math (joules).....but just think in "general terms" of the amount of energy that is now "freed up" by the loss of 15% of ice volume to either:  (1) warm the oceans more, or (2) warm the atmosphere more.

That loss of ice volume has to be truly "significant" in scientific terms.

Title: Re: 2017 sea ice area and extent data
Post by: crandles on January 04, 2017, 03:05:06 PM
plus would be impossible to do that properly before february.

For 16/17 yes, but for previous years it could be done. Putting a small symbol on the 12 actual data points and not putting one on the ends of the lines might sound tricky - perhaps possible by graph the 12 data points with symbols and also graph a 14 data-point line without symbols. That seems considerable extra work (twice number of lines, non evenly spaced data-points, and specifying same coloured lines) and would probably confuse people for some reason or another. So it is fine as it is.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on January 04, 2017, 05:06:37 PM
Is this any improvement?

- shifted the monthly labels to the right to indicate that <month> covers the interval between tick marks;
- were possible connect lines to the last month of the previous year and the first of the next (which lie outside the drawing box).
Title: Re: 2017 sea ice area and extent data
Post by: Buddy on January 04, 2017, 05:14:01 PM
Is this any improvement?

Yes...I think that is "visually" better.  It doesn't have the first half of Jan and the second half of Dec column's "missing".  So it takes away some idiot (like me) asking about it :)

I like....again....GREAT JOB.  I LOVE graphs like that....that tell a story (even when the ending is bad  :'().

Title: Re: 2017 sea ice area and extent data
Post by: A-Team on January 04, 2017, 09:10:55 PM
- shifted the monthly labels to the right to indicate that <month> covers the interval between tick marks
What about monthly labels in the middle of the column they span? Or little double-headed arrows for monthly spans?

- where possible connect lines to the last month of the previous year and the first of the next (which lie outside the drawing box).

What about extending them out to (in this instance) to their Jan extent? Right now they just go halfway. No harm in repeating a bit of the cycle (though colors change as year turns over).

Maybe make more leg room now for 2016/17 by extending ordinate to 21 or 22? Always silly accusations if a line dips below the abscissa and a tweet storm when someone shifts a graph up or down.

Note the gap to 2012 widened between Nov and Dec, from 119 to 138 pixels. So if this keeps up, ordinate would have to go to 19 or 20.
Title: Re: 2017 sea ice area and extent data
Post by: FishOutofWater on January 04, 2017, 11:51:40 PM
That graph represents a shocking increase in global ocean heat content. The extraordinarily early Antarctic melt will lead to Antarctic waters soaking up more solar energy this summer than they have since who knows when. The lack of ice in the peripheral Arctic seas will lead to early uptake of solar energy before the equinox. The snow that has been generated by storms over the peripheral seas will insulate the thin Arctic ice and keep it from thickening much this winter.

It looks like we may have crossed a into a new polar climate regime with the 2015-2016 El Niño.
Title: Re: 2017 sea ice area and extent data
Post by: Paddy on January 05, 2017, 04:19:53 AM
I'd be tempted to think so re the new regime, but I also thought 2012 might push the Arctic that way, before getting a bit of a surprise from 2013 and 2014.

The next five years could be interesting though.
Title: Re: 2017 sea ice area and extent data
Post by: kiwichick16 on January 05, 2017, 09:30:10 AM
if you look at the long term temperature graph ....for global average temperature...the step up after the 1998 El Nino is obvious...only the la Nina years of 1999 and 2000 are below the previous global record year 1997.......and since 1998 the positive feedbacks have started to have an increasing effect
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on January 05, 2017, 10:25:14 AM
- shifted the monthly labels to the right to indicate that <month> covers the interval between tick marks
What about monthly labels in the middle of the column they span? Or little double-headed arrows for monthly spans?

- where possible connect lines to the last month of the previous year and the first of the next (which lie outside the drawing box).

What about extending them out to (in this instance) to their Jan extent? Right now they just go halfway. No harm in repeating a bit of the cycle (though colors change as year turns over).

Maybe make more leg room now for 2016/17 by extending ordinate to 21 or 22? Always silly accusations if a line dips below the abscissa and a tweet storm when someone shifts a graph up or down.

Note the gap to 2012 widened between Nov and Dec, from 119 to 138 pixels. So if this keeps up, ordinate would have to go to 19 or 20.

A-Team, labels in the middle was preferred, just did not see yesterday a simple way to do it: labels seem to be always attached to tick marks. Today with a fresh look, figured out how to do it with major/minor ticks.

Further, I extended the y scale a bit for the looks. I will have to look at the graphs at the next update (which might take a long time, GIOMAS updates are very irregular) anyway.

I will think about widening the x-axis. It could be confusing.
Title: Re: 2017 sea ice area and extent data
Post by: nukefix on January 05, 2017, 11:33:01 AM
I'd like to see a version where zero is included in the y-axis..
Title: Re: 2017 sea ice area and extent data
Post by: oren on January 05, 2017, 12:24:13 PM
I'd like to see a version where zero is included in the y-axis..
No worries, in a few years even the auto-scale might get us there.
Title: Re: 2017 sea ice area and extent data
Post by: A-Team on January 06, 2017, 12:44:49 PM
extended the y scale a bit  s.  widening the x-axis. It could be confusing.
A couple of thoughts on the product distribution chain, the reachable target audience and  effective communication.

-- If just forum readers, then there are few constraints on size. The graph is inherently too complex to fit the 700 pixel dimensional constraint, ditto for the extended width with scroll bar. However it is not an animation so file size will be small even if it is 1500 pixels wide png or jpg. In that case, the forum will resize it by unknown means* to 700 pixels width and that must be intriguing enough that viewers will click on to the full size.

-- If post-forum to say Twitter, posters like Zack are able to distribute up to 1800x1200 images via that medium. The normal Twitter image on my monitor is 503x336. The larger format allowed would insure that your graphic could be distributed intact.

Note poor programming at Twitter HQ has lead to jpg:large in url terminations which browsers are processing to jpg-large which is an invalid file format not recognized by other software (until the -large is removed). This is likely related to bad programming at Twitter that is causing failure of contextual mouse menus, ie copy/paste, in their re-bundling of .mov to html5 'GIF'. It may however be intentional, to wall off Twitter from the rest of the internet, forcing people into its 'ecosystem'.

-- The WaPo is the last remaining English-language newspaper in the US covering climate change and weather at any depth and likeliest to cover significant developments. The graphic would not work at all in the WaPo print edition. Most people however would see it online, probably on an iPhone or similar with 'retinal' resolution but nonetheless tiny image (very little physical screen width).

The WaPo would reproduce the image accurately and link in to the forum original. For that reason, careful explanatory text -- even of the obvious -- is important. Also explanation of potential confusing aspects. Most other online sources like buzzfeed would simply copy the WaPo article but there's no assurance or control over image size retention or links to original context.

*Below is one of Zack's high quality Twitter images. I'm just checking here to see how the forum thumbnails large images down. That can be done by subtracting the thumbnail from the four common reductions schemes (bicubic, sinc, bilinear, none) to see if it is any of those. It might instead be lossy jpg compression in which case it won't rescale back to the original size.

So far it's emerged that the forum allows an additional 74 pixels (to 774 width) in its scroll bar configuration (which may be related to mac vs dos dpi differences of 72 vs 78). Twitter, on an iMac at 'actual size' in Opera browser, shows the thumbnail as 505x338 which includes a 1 pixel boundary of 230 gray and slightly rounded corners that chop off any information that was there in the original. Zack's 1800x1200 reduces correctly in gimp to 700 x 467 (ie 466.66667) whereas the forum reduces it to 700x467. The forum has oddly offset the title line by 11 pixels vertically and has utilized lossy compression.

In summary, it's difficult to predict what viewers see because of device variations and different choices made at Twitter, Simple Machines, browser designers and device hardware. However as long as viewers are willing to download an intact original, the potential is there to preserve scientific accuracy in the chain of transmission.
Title: Re: 2017 sea ice area and extent data
Post by: epiphyte on January 06, 2017, 05:28:29 PM
So far it's emerged that the forum allows an additional 74 pixels (to 774 width) in its scroll bar configuration/quote]

The ubiquitous presence of that scrollbar is a source of constant irritation, to me at least, since most of the graphs posted have a contour key superimposed on the extreme right side of the image, which (AFAIK, on OSX + chrome) makes it impossible to see both the Y-axis labels and the key at the same time without opening the image on a separate tab.
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on January 08, 2017, 05:06:18 PM
Update for the week to January 7th

The current 5 day trailing average is on 12,858,000km2 while the 1 day extent is at 12,852,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,142,000km2, an increase from -1,042,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -429,000km2, a decrease from -434,000km2 last week. We're currently lowest on record, up from 2nd lowest last week.

(http://i.imgur.com/xwZUbKx.png)

The average daily change over the last 7 days was +50.3k/day, compared to the long term average of +64.7k/day, and the 07, 11 and 12 average of +49.5k/day.
The average long term change over the next week is +41.8k/day, with the 07, 11, and 12 average being +63.1k/day.

(http://i.imgur.com/Je1lzBT.png)

The extent increase so far this January is the 18th smallest on record. To achieve the largest increase, a gain of at least 67.9k/day is required (at least +64.9k/day with with single day values), while the smallest increase requires a gain of less than 28.7k/day (less than 22.1k/day with single day values) and an average increase requires a gain of 49.1k/day (gain of 37.8k/day with single day values).

(http://i.imgur.com/wIXRVfO.png)
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on January 13, 2017, 02:41:51 PM
Global sea ice area now record low.

Huge NSIDC global drops: quad century extent, triple century area. Data from Uni Hamburg and Uni Bremen seem to confirm this, so no satellite failure.

As a consequence, global area has now dropped below the all time (satellite era) low set in February 2016. Global extent is at the fourth position after 2016, 2011 and 2006.

Current positions:

Extent:
2016-02-17, 16.708708
2006-01-30, 16.766292
2011-02-22, 16.789130
2017-01-12, 16.895409
2005-02-07, 17.136978

Area:
2017-01-12, 13.707421
2016-02-21, 13.961025
2006-02-24, 14.196194
2011-01-23, 14.379586
2005-02-22, 14.472310

Title: Re: 2017 sea ice area and extent data
Post by: Paddy on January 13, 2017, 03:53:08 PM
And surely it won't be long before global extent is at a record low too. The question, I suppose, is how low they both go.
Title: Re: 2017 sea ice area and extent data
Post by: CognitiveBias on January 13, 2017, 03:59:44 PM
I'm curious about global volume.  Anyone have data?
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on January 13, 2017, 04:06:48 PM
I'm curious about global volume.  Anyone have data?

I have assembled a global sea ice page here:
https://sites.google.com/site/arctischepinguin/home/global-sea-ice

At the bottom is a GIOMAS global sea ice volume graph, also attached.
Title: Re: 2017 sea ice area and extent data
Post by: oren on January 13, 2017, 04:08:38 PM
I was just about to post the same. I recommend to bookmark this page, and a big thanks to the untiring Wipneus.
Title: Re: 2017 sea ice area and extent data
Post by: Buddy on January 13, 2017, 04:21:22 PM
I was just about to post the same. I recommend to bookmark this page, and a big thanks to the untiring Wipneus.

The VOLUME chart is......STAGGERING.  Area or extent can be effected by weather rather quickly...but VOLUME.  That has to be a function of weather AND OCEAN TEMPS.  And once the volume has gone away....it isn't going to come back as quickly.

Not good.....

Title: Re: 2017 sea ice area and extent data
Post by: Neven on January 13, 2017, 04:38:25 PM
Thanks, Wipneus, I was about to ask you to notify me when the record(s) would get broken, but here we are...

Post is up on the ASIB (http://neven1.typepad.com/blog/2017/01/global-sea-ice-records-broken-again.html).

BTW, those two global sea ice area and extent graphs are now included on the ASIG (https://sites.google.com/site/arcticseaicegraphs/).
Title: Re: 2017 sea ice area and extent data
Post by: magnamentis on January 13, 2017, 06:29:18 PM
Thanks, Wipneus, I was about to ask you to notify me when the record(s) would get broken, but here we are...

Post is up on the ASIB ([url]http://neven1.typepad.com/blog/2017/01/global-sea-ice-records-broken-again.html[/url]).

BTW, those two global sea ice area and extent graphs are now included on the ASIG ([url]https://sites.google.com/site/arcticseaicegraphs/[/url]).


thanks for inclusion, just wanted to propose that :-)
Title: Re: 2017 sea ice area and extent data
Post by: Lord M Vader on January 13, 2017, 07:20:26 PM
Wipneus: As the sea ice minimum around Antarctica is roughly a month away as well as the Arctic maximum is 1-2 months away, will you make any estimations on gains/drops? This year is extremely interesting as we might get

* a record low SIE minimum around Antarctica
* a record low SIE maximum in Arctic

Best, LMV

Title: Re: 2017 sea ice area and extent data
Post by: anotheramethyst on January 14, 2017, 08:41:18 AM
Staggering and terrifying.  I wonder how much of that was caused by the el nino and how much of that is just the new normal for the arctic and antarctic. 
Title: Re: 2017 sea ice area and extent data
Post by: oren on January 14, 2017, 10:40:57 AM
In the antarctic I am pretty sure it's nino-driven for the most part. In the arctic though it's mostly the long term trend that has passed another phase shift.
Title: Re: 2017 sea ice area and extent data
Post by: Carex on January 14, 2017, 08:24:21 PM
Do I eyeball that volume deficit correctly at ~ 4,000km3?  Or about the volume of fresh water that humans use per year. (volume source https://www.scientificamerican.com/article/why-dont-we-get-our-drinking-water-from-the-ocean/ (https://www.scientificamerican.com/article/why-dont-we-get-our-drinking-water-from-the-ocean/))
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on January 15, 2017, 02:19:09 PM
Global Sea Ice Extent is now record low.

Global Sea Ice Area broke the minimum record a couple of days ago. Now a 150k drop makes the global sea ice extent drop below all previous (in the satellite era) records. That is about one month before the annual minimum normally can be expected.

How low will it go? Will the global ice ever return to "normality"? I have no idea.

                                                 normalized normalized
             global   global    global    global     global     global
      date   extent     area  ext.anom area.anom   ext.anom  area.anom
2017-01-05   17.936   14.426    -2.298    -2.025     -3.277     -3.563
2017-01-06   17.699   14.186    -2.424    -2.211     -3.409     -3.891
2017-01-07   17.618   14.037    -2.398    -2.308     -3.335     -4.067
2017-01-08   17.573   14.066    -2.340    -2.228     -3.237     -3.936
2017-01-09   17.445   14.058    -2.368    -2.185     -3.277     -3.880
2017-01-10   17.310   14.075    -2.406    -2.119     -3.339     -3.786
2017-01-11   17.330   14.025    -2.295    -2.124     -3.190     -3.814
2017-01-12   16.895   13.707    -2.644    -2.398     -3.681     -4.333
2017-01-13   16.849   13.711    -2.608    -2.355     -3.641     -4.283
2017-01-14   16.693   13.659    -2.687    -2.368     -3.763     -4.334


Title: Re: 2017 sea ice area and extent data
Post by: Archimid on January 15, 2017, 02:47:29 PM
Yet one more graph probably going literally off the charts. I bet that if some one was keeping track of all climate and biologic time series and could somehow normalize them, an increase in literal  "off the charts" events could be detected. If some negative feedback does not kick in soon, the number of literally "off the charts" events will keep increasing.
Title: Re: 2017 sea ice area and extent data
Post by: DrTskoul on January 15, 2017, 05:09:59 PM
Yet one more graph probably going literally off the charts. I bet that if some one was keeping track of all climate and biologic time series and could somehow normalize them, an increase in literal  "off the charts" events could be detected. If some negative feedback does not kick in soon, the number of literally "off the charts" events will keep increasing.
.

 With such a large external forcing applied so rapidly, I don't see a natural negative feedback that is both large and not previously detected/theorised , appearing all of the sudden.  Unless it is a nuclear war, asteroid impact, geoengineering or us stopping and reversing CO2 emissions.

Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on January 15, 2017, 07:02:14 PM
Update for the week to January 14th

The current 5 day trailing average is on 12,906,000km2 while the 1 day extent is at 12,855,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,387,000km2, an increase from -1,142,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -556,000km2, an increase from -429,000km2 last week. We're currently lowest on record, the same last week.

(http://i.imgur.com/VqwiVqn.png)

The average daily change over the last 7 days was +6.9k/day, compared to the long term average of +41.8k/day, and the 07, 11 and 12 average of +63.1k/day.
The average long term change over the next week is +39.9k/day, with the 07, 11, and 12 average being +33.5k/day.

(http://i.imgur.com/TSjpscY.png)

The extent increase so far this January is the 3rd smallest on record. To achieve the largest increase, a gain of at least 80.7k/day is required (at least +94.9k/day with with single day values), while the smallest increase requires a gain of less than 25.4k/day (less than 32.3k/day with single day values) and an average increase requires a gain of 54.2k/day (gain of 64.8k/day with single day values).

(http://i.imgur.com/LaFtIMu.png)
Title: Re: 2017 sea ice area and extent data
Post by: Sigmetnow on January 16, 2017, 12:26:09 AM
Eric Holthaus:  Wait for it... yikes.

Watch the GIF at the link below:

Final version of the Global Sea Ice Area spiral plot #climatechange #globalwarming
https://mobile.twitter.com/kevpluck/status/817126011435446273
Title: Re: 2017 sea ice area and extent data
Post by: magnamentis on January 16, 2017, 11:09:06 AM
thank you to share this one  :)
Title: Re: 2017 sea ice area and extent data
Post by: Jim Pettit on January 16, 2017, 03:37:40 PM
Things still pointing at record low extent maxima--though, as always, we'll see:

IJIS:
(http://iwantsomeproof.com/extimg/sie_projections_from_current_date.png)
(http://iwantsomeproof.com/extimg/sie_current_with_anomaly.png)

NSIDC:
(http://iwantsomeproof.com/extimg/nsidc_projections_from_current_date.png)
(http://iwantsomeproof.com/extimg/nsidc_current_sie_with_anomaly.png)

Strange days, indeed. Most peculiar, mama...
Title: Re: 2017 sea ice area and extent data
Post by: DrTskoul on January 16, 2017, 04:20:05 PM
What are the respective minimum maxima for the graphs below?
Title: Re: 2017 sea ice area and extent data
Post by: Buddy on January 16, 2017, 04:56:19 PM
Things still pointing at record low extent maxima--though, as always, we'll see:

Not good.  From Jim's chart above.... "Lower highs....and lower lows" from a "charting standpoint."  If you look at the bright red lines representing sea ice anomaly you see those "lower highs and lower lows" clearly.  In 2017 it looks like that 3 million K2 anomaly could come into play this fall.

And from a FUNDAMENTAL SCIENCE STANDPOINT....that is what I would expect...something in that "ballpark". :-[



 



Title: Re: 2017 sea ice area and extent data
Post by: charles_oil on January 16, 2017, 05:53:15 PM
Jim -

Could your excellent "projection" charts be annotated with the respective record low maximum lines as that is the current concern (they just have the record low minimum lines) ?

Thanks
Title: Re: 2017 sea ice area and extent data
Post by: Ajpope85 on January 16, 2017, 07:35:44 PM
Eric Holthaus:  Wait for it... yikes.

Watch the GIF at the link below:

Final version of the Global Sea Ice Area spiral plot #climatechange #globalwarming
https://mobile.twitter.com/kevpluck/status/817126011435446273

That almost looks like a decaying satellite orbit that's about to smash into a planet.
Title: Re: 2017 sea ice area and extent data
Post by: Jim Pettit on January 16, 2017, 07:46:50 PM
Jim -

Could your excellent "projection" charts be annotated with the respective record low maximum lines as that is the current concern (they just have the record low minimum lines) ?

Thanks

What are the respective minimum maxima for the graphs below?


As requested:

IJIS:
(http://iwantsomeproof.com/extimg/sie_projections_from_current_date.png)

NSIDC:
(http://iwantsomeproof.com/extimg/nsidc_projections_from_current_date.png)
Title: Re: 2017 sea ice area and extent data
Post by: charles_oil on January 16, 2017, 07:49:46 PM
Thanks Jim ...

So looks like no year since 2003 has seen enough growth from this sate that we could get above the lowest maximum..... and these were presumably much less stormy years.  Curiously 2012 looks like the highest growth from this point... till the drop starts !
Title: Re: 2017 sea ice area and extent data
Post by: DrTskoul on January 16, 2017, 08:30:59 PM
Thanks Jim.... Fascinating  :o
Title: Re: 2017 sea ice area and extent data
Post by: Gray-Wolf on January 16, 2017, 09:05:21 PM
The only reason 2012 saw that late surge was the 'ice factory' setting up over the Bering Straights. None of that 'extension' was 'good ice' as it all fell ourside the basin and so drove the rapid collapse we saw in early season (not that this stopped the usual suspects crying 'recovery/record' as though meaningful?).

The real action from now until melt season is the thickening and 'conditioning' of the ice prior to melt season. This storm may well bring a halt , basin wide, to this activity?

It is the same as the 2014 and 2015 extension to the Antarctic sea ice which , to anyone caring to notice, was an early brake up/float off of the peripheral pack at freezing seasons end. Take that 'growth spurt' away and you see a melt season beginning just as 2016 has done ( but to more raised eyebrows ) now the Pacific drivers now demand such.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on January 19, 2017, 06:53:44 PM
Cross post from the not-so-stupid-questions thread:

Are the NSIDC links moved are just experiencing tech problems?


They have moved , with some other changes as well:

https://nsidc.org/the-drift/data-update/sea-ice-index-ftp-directory-structure-changing/

On 31 Jan the ftp will be closed and all that data can only be accessed from the protected (user+password, free registration) https connection. Start here and find the rest:

https://daacdata.apps.nsidc.org/pub/DATASETS/NOAA/G02135/

etcetera.
Title: Re: 2017 sea ice area and extent data
Post by: Pmt111500 on January 20, 2017, 03:17:03 AM
(public notification) Please someone take a copy of the ftp-file and check it line by line (including non-written characters) against the passworded file afterwards. Not sure if this would be good to do via entirely new machinery. New email address could be used, or if you trust the future government sign up with your current address using your bank account details as password. Remember, if you've got nothing to hide, you got nothing to be afraid. (/mistrust of denialists)
Title: Re: 2017 sea ice area and extent data
Post by: epiphyte on January 20, 2017, 04:00:33 PM
Remember, if you've got nothing to hide, you got nothing to be afraid.

When people say this to me I always ask to go through their wallet. It usually ends the argument right there!
Title: Re: 2017 sea ice area and extent data
Post by: magnamentis on January 20, 2017, 04:11:13 PM
Remember, if you've got nothing to hide, you got nothing to be afraid.

When people say this to me I always ask to go through their wallet. It usually ends the argument right there!

good idea indeed, will remember that one because that saying drives me mad. it's the same people who even hide their belly button LOL. another idea would be to ask them to visit a nudist beach.
END [OT] just coudn't resist

cheers
Title: Re: 2017 sea ice area and extent data
Post by: Tealight on January 20, 2017, 07:34:05 PM
Are the NSIDC links moved are just experiencing tech problems?


They have moved , with some other changes as well:

https://nsidc.org/the-drift/data-update/sea-ice-index-ftp-directory-structure-changing/

On 31 Jan the ftp will be closed and all that data can only be accessed from the protected (user+password, free registration) https connection. Start here and find the rest:

https://daacdata.apps.nsidc.org/pub/DATASETS/NOAA/G02135/

etcetera.

Wipneus, have you already switched your scripted data downloads to the HTTPS? If so, what method did you use to access the data?
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on January 21, 2017, 09:12:27 AM

Wipneus, have you already switched your scripted data downloads to the HTTPS? If so, what method did you use to access the data?

I am working on it, it is a major pain.

First NSIDC suggets using firefox (with "downthemall addin), wget or curl tools:
https://nsidc.org/support/faq/what-options-are-available-bulk-downloading-data-https-earthdata-login-enabled

That offers no solutions for my scripts, that streamlines the download with the processing of the data files. Http(s) is not a protocol designed for pure data access and  requires reading webpages, pseudo-sessions with authorization, handling cookies and  connection reuse.
I found that the "python-scripts" package does these things out of the box and am currently testing the solution. The https access is much slower than ftp (also with wget, it is not my sloppy programming), so I am using the multi-threading library "joblib" to speed things up a bit.


Title: Re: 2017 sea ice area and extent data
Post by: Pmt111500 on January 21, 2017, 09:25:25 AM
interesting they're doing the transfer to inefficient https just now. They thus increase the costs of data transmission. I'll hazard a guess they'll use this totally unnecessary insertion of unsafe scripts as an excuse to cut down true science.
Title: Re: 2017 sea ice area and extent data
Post by: Sourabh on January 21, 2017, 01:22:17 PM
If possible, can anyone post area numbers? What is happening to the area these days? :-\ :-\ :-\

Are we also experiencing shocking "recovery" in area as well?    ;) ;)
Title: Re: 2017 sea ice area and extent data
Post by: DavidR on January 22, 2017, 08:39:18 AM
Wipneus's area and extent graphs show that  most  of the recent  increase has occurred in the North Pacific.

https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-area-regional.png

https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-extent-regional.png

Within the Arctic basin there appears to  have been slight declines as predicted earlier.  Baffin and Greenland are up slightly but  many of the other seas are declining or flat. This suggests we will  see a year where the early decline will be similar to 2016 but the real  damage will appear when the central ice collapses when  summer comes.

Title: Re: 2017 sea ice area and extent data
Post by: jdallen on January 22, 2017, 10:33:04 AM
Wipneus's area and extent graphs show that  most  of the recent  increase has occurred in the North Pacific.
In short, the extent and area increases we've seen over the last few days (about 500K KM2) have mostly taken place in peripheral areas which will start melting out rapidly in 6-8 weeks.

Not a lot to be happy about there, I'm afraid.
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on January 22, 2017, 09:24:41 PM
Update for the week to January 21st

The current 5 day trailing average is on 13,187,000km2 while the 1 day extent is at 13,373,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,386,000km2, a decrease from -1,387,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -510,000km2, a decrease from -556,000km2 last week. We're currently lowest on record, the same last week.

(http://i.imgur.com/pi1SGsj.png)

The average daily change over the last 7 days was +40.1k/day, compared to the long term average of +39.9k/day, and the 07, 11 and 12 average of +33.5k/day.
The average long term change over the next week is +35.3k/day, with the 07, 11, and 12 average being +44.4k/day.

(http://i.imgur.com/jI61Zr1.png)

The extent increase so far this January is the 5th smallest on record. To achieve the largest increase, a gain of at least 109.1k/day is required (at least +113.1k/day with with single day values), while the smallest increase requires a gain of less than 15.2k/day (loss of at least 4.5k/day with single day values) and an average increase requires a gain of 64.0k/day (gain of 56.7k/day with single day values).

(http://i.imgur.com/rxrs7dy.png)
Title: Re: 2017 sea ice area and extent data
Post by: Ice Shieldz on January 22, 2017, 10:59:17 PM
BornFromTheVoid, that 7 Day Extent Change says a lot.  The line for 2016/17 has an exceptional wave sinuosity.  It would be very interesting to overlay markers for each major arctic storm, and see how they align with 2016/17 wave peaks and troughs.
Title: Re: 2017 sea ice area and extent data
Post by: cartographer on January 23, 2017, 10:50:32 PM
interesting they're doing the transfer to inefficient https just now. They thus increase the costs of data transmission. I'll hazard a guess they'll use this totally unnecessary insertion of unsafe scripts as an excuse to cut down true science.

There has been an effort throughout NOAA, at least, to move to https by year's end to improve data and system security. This was ongoing before the election and so shouldn't be seen as a consequence thereof.
Title: Re: 2017 sea ice area and extent data
Post by: Jim Pettit on January 28, 2017, 05:13:36 PM
Despite the recordsetting (for late January) increase in NH sea ice extent over the past two weeks, 2017 is still far ahead of the rest of the pack so far as the year-to-date/month-to-date daily average is concerned. Here's NSIDC:

(http://image.prntscr.com/image/faf3484c85ac4512a9c50749f37c6cdf.png)

Also despite that recordsetting increase, total extent change for the month is still running lower than the 2007-2016 average.

ADS-NIPR (IJIS) Extent:
13,077,599 km2 (27 January)
9,961,502 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 61,358 km2 (-0.47%) from previous day.
Up 208,732 km2  (1.62%) over past seven days (daily average: 29,819 km2).
Up 980,803 km2  (8.11%) for January (daily average: 36,326 km2).
861,841 km2 below 2000s average for this date.
311,321 km2 below 2010s average for this date.
149,514 km2 below 2016 value for this date.
377,460 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 27 January) average.
Lowest January to-date average.
Lowest value for the date.
18 days this year (66.67% year-to-date) have recorded the lowest daily extent.
7 days (25.93%) have recorded the second lowest.
0 days (0%) have recorded the third lowest.
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on January 29, 2017, 03:11:40 PM
Update for the week to January 28th

The current 5 day trailing average is on 13,714,000km2 while the 1 day extent is at 13,655,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,106,000km2, a decrease from -1,386,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -294,000km2, a decrease from -510,000km2 last week. We're currently 2nd lowest on record, the same last week.

(http://i.imgur.com/tPKlLwq.png)

The average daily change over the last 7 days was +75.3k/day, compared to the long term average of +35.3k/day, and the 07, 11 and 12 average of +44.4k/day.
The average long term change over the next week is +34.4k/day, with the 07, 11, and 12 average being +23.7k/day.

(http://i.imgur.com/8Z2rPSu.png)

The extent increase so far this January is the 18th smallest on record. To achieve the largest increase, a gain of at least 187.8k/day is required (at least +510.6k/day with with single day values), while the smallest increase requires a loss of at least 125.0k/day (loss of at least 271.3k/day with single day values) and an average increase requires a gain of 37.7k/day (gain of 135.5k/day with single day values).

(http://i.imgur.com/itM05ad.png)
Title: Re: 2017 sea ice area and extent data
Post by: Jim Pettit on February 01, 2017, 01:40:56 PM
January was another record-breaking month in the Arctic. Only slightly below average extent increase, but a far below noremal monthly average.

IJIS:
(http://image.prntscr.com/image/c624208e70a744f8ba444fd84352bba4.png)
(http://image.prntscr.com/image/8fab279c6f2346d0ac88408ec04fc8c5.png)

NSIDC:
(http://image.prntscr.com/image/a5f75dbf2cb14af6a6f1e816c428c4eb.png)
(http://image.prntscr.com/image/ce94ad30f43c467c8203b8a2cc81daa1.png)

IJIS extent is still roughly three-quarters of a million km2 below the low record maximum set in 2015 (and almost equalled again last year). With roughly six weeks of ice growth still to go (between two weeks [2015] and nine weeks [2010]), 2017 may or may not set a new record; five years out of the last ten saw enough extent increase after this date to set a new low maximum record, and the other half didn't. Far more importantly, however, is the fact that even with extent likely to spread, it's thin and it's frangible, and isn't likely to linger.
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on February 05, 2017, 05:20:44 PM
Update for the week to February 4th

The current 5 day trailing average is on 13,828,000km2 while the 1 day extent is at 13,834,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,232,000km2, an increase from -1,106,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -345,000km2, an increase from -294,000km2 last week. We're currently lowest on record, up from 2nd lowest last week.

(https://i.imgur.com/dLNm802.png)

The average daily change over the last 7 days was +16.4k/day, compared to the long term average of +34.4k/day, and the 07, 11 and 12 average of +23.7k/day.
The average long term change over the next week is +21.1k/day, with the 07, 11, and 12 average being +23.2k/day.

(https://i.imgur.com/nwcaPgw.png)

The extent increase so far this February is the 19th smallest on record. To achieve the largest increase, a gain of at least 29.6k/day is required (at least +31.9k/day with with single day values), while the smallest increase requires a loss of at least 1.8k/day (loss of at least 2.3k/day with single day values) and an average increase requires a gain of 18.3k/day (gain of 19.7k/day with single day values)

(https://i.imgur.com/fg7P2PH.png)

The extent increase in January was the 13th smallest on record while the average extent was the lowest on record.

(https://i.imgur.com/3ULtqlf.png)
(https://i.imgur.com/LpNtkbg.png)
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on February 08, 2017, 02:29:24 PM
NSIDC area dropped -124k6, half of the loss in Okhotsk region.

Area graphs are rare after the CT stopped updating, attached is the spaghetti graph based on area calculated from NSIDC area.

Title: Re: 2017 sea ice area and extent data
Post by: DrTskoul on February 08, 2017, 02:33:30 PM
Thank you Wip for the rare delight....
Title: Re: 2017 sea ice area and extent data
Post by: Pmt111500 on February 08, 2017, 03:18:29 PM
Thanks Wipneus, I still prefer area graphs and values over extent mesh. Too bad ct sia is so hard to connect well to the current data formats. I've given up on that and just take what the good people here including you provide. Anyway my stat skills on the better programs than spreadsheet stuff is not there but thebsimple longperiod sets are easily analysed even by those who are not as good analysts as many here. There's imho nothing more convincing than calculating the reality of climate change yourself.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on February 09, 2017, 02:45:20 PM
"NSIDC area" second century drop in two days: -110k. CAB, Okhotsk and Greenland Sea.
Title: Re: 2017 sea ice area and extent data
Post by: Apocalypse4Real on February 11, 2017, 02:21:13 AM
Wipneus,

Great stuff! I review your graphs daily.

A4R
Title: Re: 2017 sea ice area and extent data
Post by: Chuck Yokota on February 12, 2017, 04:56:53 AM
Am I reading the graph correctly, that NSIDC area has been the record lowest every day since mid-October?
Title: Re: 2017 sea ice area and extent data
Post by: DrTskoul on February 12, 2017, 05:15:34 AM
Am I reading the graph correctly, that NSIDC area has been the record lowest every day since mid-October?

Yes... :o
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on February 12, 2017, 04:57:32 PM
Update for the week to February 11th

The current 5 day trailing average is on 13,895,000km2 while the 1 day extent is at 13,864,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,312,000km2, an increase from -1,232,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -441,000km2, an increase from -345,000km2 last week. We're currently lowest on record, the same as last week.

(http://i.imgur.com/LEctgPC.png)

The average daily change over the last 7 days was +9.6k/day, compared to the long term average of +21.1k/day, and the 07, 11 and 12 average of +23.2k/day.
The average long term change over the next week is +17.4k/day, with the 07, 11, and 12 average being +33.3k/day.

(http://i.imgur.com/QW23H1m.png)

The extent increase so far this February is the 11th smallest on record. To achieve the largest increase, a gain of at least 37.7k/day is required (at least +45.0k/day with with single day values), while the smallest increase requires a loss of at least 6.4k/day (loss of at least 5.3k/day with single day values) and an average increase requires a gain of 21.8k/day (gain of 26.8k/day with single day values).

(http://i.imgur.com/A7NIJNt.png)
Title: Re: 2017 sea ice area and extent data
Post by: Jim Pettit on February 15, 2017, 03:17:08 PM
A quick snapshot of an NSIDC Arctic SIE chart to show that, even with the big uptick the last few days, 2017 is still looking pretty weak and pathetic:

(http://iwantsomeproof.com/extimg/sie_nsidc_daily_for_selected_years.png)
Title: Re: 2017 sea ice area and extent data
Post by: jdallen on February 15, 2017, 04:55:27 PM
If we get the forecast 7-10 days of "normal" temperatures, It wouldn't surprise me if area and extent spiked up as much as 500,000 KM2.  At this juncture, none of that ice formed is likely to get past 50CM of thickness.  None of the existing ice is likely to thicken more than about another 10CM.

When the weather turns, it will draw back just as rapidly.  QED, I expect we'll hit max around or about the 25th of February.
Title: Re: 2017 sea ice area and extent data
Post by: Gray-Wolf on February 15, 2017, 05:06:09 PM
A sense a moment of Deja vu approaching!!

In 2012 the ice factory turned on around now and took extent on a little excursion.

Deniers went bonkers with their demands for a 'recovery' to be accepted even though we all told then that late extension, outside basin ice would make no difference to the final figures.

They went very quiet after that right up until the storm arrived and then they tried to claim the whole of the melt seasons behaviour boiled down to the impacts of that 1 storm..........

With the Arctic so much in the news this winter I very much fear that any signs of the ice extent/area approaching 'average' will set them off again?

We all know we have a very bad , potentially disastrous if the weather favours melt/export, so having to put them straight for the first 6 weeks of melt season will be wearing!!!
Title: Re: 2017 sea ice area and extent data
Post by: Shared Humanity on February 16, 2017, 12:24:24 AM
A sense a moment of Deja vu approaching!!

In 2012 the ice factory turned on around now and took extent on a little excursion.

Deniers went bonkers with their demands for a 'recovery' to be accepted even though we all told then that late extension, outside basin ice would make no difference to the final figures.

They went very quiet after that right up until the storm arrived and then they tried to claim the whole of the melt seasons behaviour boiled down to the impacts of that 1 storm..........

With the Arctic so much in the news this winter I very much fear that any signs of the ice extent/area approaching 'average' will set them off again?

We all know we have a very bad , potentially disastrous if the weather favours melt/export, so having to put them straight for the first 6 weeks of melt season will be wearing!!!

Don't set them straight. Let them spout their nonsense and stew in their own juices when their ignorance becomes obvious.
Title: Re: 2017 sea ice area and extent data
Post by: RoxTheGeologist on February 16, 2017, 03:08:36 AM

Extent is a dangerously noisy value to base Climate Change arguments on; in winter it will recover, it's cold enough to freeze the top layer of the ocean and extent changes dramatically depending on the weather. It hands the prerogative back to the deniers whenever there is a week of cold weather. It would be better to shift the argument to volume or to FDDs. We know that the arctic sea ice is the canary in the coal mine and that it is the place where climate change is most easily observed. Why do we continue to argue about the one parameter that actually does not correlate well with FDDs?
Title: Re: 2017 sea ice area and extent data
Post by: Iceismylife on February 16, 2017, 04:04:06 AM

Extent is a dangerously noisy value to base Climate Change arguments on; in winter it will recover, it's cold enough to freeze the top layer of the ocean and extent changes dramatically depending on the weather. It hands the prerogative back to the deniers whenever there is a week of cold weather. It would be better to shift the argument to volume or to FDDs. We know that the arctic sea ice is the canary in the coal mine and that it is the place where climate change is most easily observed. Why do we continue to argue about the one parameter that actually does not correlate well with FDDs?
Tell that to the IPCC.  They define ice free in extent.
Title: Re: 2017 sea ice area and extent data
Post by: JMP on February 16, 2017, 05:09:23 AM

Extent is a dangerously noisy value to base Climate Change arguments on; in winter it will recover, it's cold enough to freeze the top layer of the ocean and extent changes dramatically depending on the weather. It hands the prerogative back to the deniers whenever there is a week of cold weather. It would be better to shift the argument to volume or to FDDs. We know that the arctic sea ice is the canary in the coal mine and that it is the place where climate change is most easily observed. Why do we continue to argue about the one parameter that actually does not correlate well with FDDs?
Tell that to the IPCC.  They define ice free in extent.
Point taken. 
But.  I'm thinking that the scientists of the IPCC understand what's going on even if that's not explicitly reflected in statements to the public.  There are references to thickness and concentration on their site for instance - though a search for extent, even, returned no results from their home page.  I seriously doubt the scientists/science comprehension at the IPCC are/is the difficulty.  Blah blah blah.

Let's not overlook that Rox has a great point here! 

Extent should almost come with a disclaimer imho. Particularly because late season gains have been mischaracterized as legitimate recovery.  And, while it may all be a bit difficult to get at first glance, thickness, area, extent, and volume, are all readily comprehensible terms that I've never seen delineated or discussed in the regular media.  And so I think too, facilitating the discussion of these terms is in everyone's interest.
Title: Re: 2017 sea ice area and extent data
Post by: Feeltheburn on February 16, 2017, 05:35:38 AM

Extent is a dangerously noisy value to base Climate Change arguments on; in winter it will recover, it's cold enough to freeze the top layer of the ocean and extent changes dramatically depending on the weather. It hands the prerogative back to the deniers whenever there is a week of cold weather. It would be better to shift the argument to volume or to FDDs. We know that the arctic sea ice is the canary in the coal mine and that it is the place where climate change is most easily observed. Why do we continue to argue about the one parameter that actually does not correlate well with FDDs?

Good point. However, I believe DMI modeled ice thickness, for example, only goes back to 2003, while ice extent goes back to 1979 (unofficially back to 1974?), so ice extent may be the only way to compare apples and apples all the way back to 1979. Please someone correct me if I'm wrong and point to where we can find reliable ice thickness data as far back as 1979.
Title: Re: 2017 sea ice area and extent data
Post by: oren on February 16, 2017, 07:17:11 AM
The IPCC focuses on summer extent which does correlate with AGW. Winter extent (at this stage at least) is mostly semi-random numbers in the periphery. The current long-term process of the arctic is turning large parts of it (all of it eventually) to be seasonally ice-free. Some parts are undergoing change to almost year-round ice-free, but that is still very limited (mainly Barents area).
Title: Re: 2017 sea ice area and extent data
Post by: DoomInTheUK on February 16, 2017, 10:16:06 AM

...We know that the arctic sea ice is the canary in the coal mine .....

The way it's looking at the moment, it's more of a canary in a taxidermists.  :)
Title: Re: 2017 sea ice area and extent data
Post by: Neven on February 16, 2017, 10:35:33 AM
Good point. However, I believe DMI modeled ice thickness, for example, only goes back to 2003, while ice extent goes back to 1979 (unofficially back to 1974?), so ice extent may be the only way to compare apples and apples all the way back to 1979. Please someone correct me if I'm wrong and point to where we can find reliable ice thickness data as far back as 1979.

There are obviously no observations (except perhaps for submarine data), but PIOMAS has modelled data going back that far, I believe.
Title: Re: 2017 sea ice area and extent data
Post by: Gray-Wolf on February 16, 2017, 11:42:38 AM
I think this sudden need for accurate data of the old Arctic is suspect? We have plenty of ships data describing the scale of the ice from the 1800's onward and we know that there is nothing like the conditions witnessed then anywhere in the basin now. All we know is that the slow 'drip ,drip' forcing through the 20th Century did away with all of that ice, ice big enough to build military bases ans radar station on!( the 'T' islands).

Sadly I believe this is an attempt to set up a straw man.

The fact that we had a hell of a lot more ice, some truly massive chunks from Ward Hunt etc. and all of that ice is gone. We are not only at the rump end of the pack it would appear that we now have a 'different pack' of thinner, warmer, younger ice to that of the last Century.
Title: Re: 2017 sea ice area and extent data
Post by: seaicesailor on February 16, 2017, 12:17:38 PM
... All we know is that the slow 'drip ,drip' forcing through the 20th Century did away with all of that ice, ice big enough to build military bases ans radar station on!( the 'T' islands)....
Nice that you point that out. In particular, Fletcher (T-3) Ice Island lasted from 1946 to 1983. It was a 14x8 km iceberg, with an estimated thickness of 50 to 60 m, and its stability allowed for harboring meteo stations, military base,...
It seems difficult to imagine how a loose drifting piece of ice whatever its origin would survive for 20 almost 40 years in the current Arctic.
https://en.wikipedia.org/wiki/Fletcher's_Ice_Island
Excuses for the (nice) off topic
PS. The origin of this island as well as many others documented in the mid 20th century, was the Ellesmere Ice Shelf, which split and disintegrated from 2002 to 2008 in many pieces.
https://en.wikipedia.org/wiki/Ellesmere_Ice_Shelf
PPS. The last image shows the drift of T-3 from early 50's to 1975. It basically spent 20+ years in regions of the Gyre that have become seasonally ice-free nowadays. Perspective!
Title: Re: 2017 sea ice area and extent data
Post by: DrTskoul on February 16, 2017, 12:22:55 PM
All this renewed discussion about Area, Extent, Volume, newly added FDDs, is a recurring feature in the forum.  Whenever uncertainty is high we start questioning again. What has been established in the previous cycle of discussion.

All the important observational data from 1800s to the early 80s (charts, expedition information, later submarine thickness data and satellite images, all point to the same picture of ice and thickness and area abundance and define the box.  Today's arctic is so far from those box boundaries that it does not even matter to accurately represent those edges for the analysis of our current dire state. We are too impatient and the natural noise frequency too small to satisfy our impatience. However the forcings are set and known and the internal variability irrelevant to the final outcome.

Going back and questioning what the ice was in the 70s and 80s is unnecessary... It has been documented in the prior posts in this Forum. Search is your friend...

Our best bet is to try and see if we can understand the mechanisms of this spurts of ups and downs. It is a window to the internal variability drivers. Lots to learn there.

And another comment. FDDs are a great probe of the average state of the arctic.  Localised over small areas lessens the usefuleness, since advection of ice comes into play.  Locally high FDDs mean nothing if the ice is mobile and has a small residence time in the high FDD zone.  Conversly, low FDDs and slow moving ice is a recipe for a disaster..
Title: Re: 2017 sea ice area and extent data
Post by: gerontocrat on February 16, 2017, 03:50:59 PM
FDD's, extent, volume, area etc.

50 years ago I was at University doing Pure Maths. Maybe then I could have done the maths that forms a large part of this forum. But now this tired old brain cannot. The only maths I do these days can be done on a 2 quid calculator (though I have been known to occasionally venture into cubic measures).

However, I read a large proportion of these posts and classify them by using a simple statistical ranking analysis. North is arctic ice recovery, South is where we are going. So the current FDD anomaly points strongly South. The last three months PIOMAS volumes point very strongly South because of a) persistence and b) happening in winter. The DMI graph for 80+ North points strongly South because it is not just one winter. The last couple of days increase in sea ice extent - a small North but offset by strong sea ice drift dispersing and breaking up parts of the ice cap.

And so on and so on. The speculative conclusion is that Winter Sea Ice is showing increased decline, with presumable a major impact on summer ice . But with a caveat. Archaeologists have a rule when they are digging - "It takes three bricks to make a wall". Perhaps speculation on a new winter sea ice environment can only become a hypothesis when we see three significant record low years close together?

A slow-motion train wreck is - slow. Mind you as a total hypocrite I am on tenterhooks waiting for the PIOMAS February volume reporrt.



Title: Re: 2017 sea ice area and extent data
Post by: Jim Williams on February 16, 2017, 04:06:30 PM
And so on and so on. The speculative conclusion is that Winter Sea Ice is showing increased decline, with presumable a major impact on summer ice . But with a caveat. Archaeologists have a rule when they are digging - "It takes three bricks to make a wall". Perhaps speculation on a new winter sea ice environment can only become a hypothesis when we see three significant record low years close together?

When I look at the DMI 80N since the beginning of 2016 I count 9 bricks.  The bottom temp simply has not been able to break through 247 in 9 tries.
Title: Re: 2017 sea ice area and extent data
Post by: josh-j on February 16, 2017, 09:04:40 PM
When I look at the DMI 80N since the beginning of 2016 I count 9 bricks.  The bottom temp simply has not been able to break through 247 in 9 tries.

Indeed DMI 80N has not dropped below the green line (in winter) since December 2015. :o

I can't see any year other than 2016 that has the property of being always above average in DMI 80N (well, there is also 2017 so far..). However I don't have the knowledge to make my speculation worth much if I was to start predicting next winter!
Title: Re: 2017 sea ice area and extent data
Post by: Jim Williams on February 17, 2017, 12:33:59 AM
When I look at the DMI 80N since the beginning of 2016 I count 9 bricks.  The bottom temp simply has not been able to break through 247 in 9 tries.

Indeed DMI 80N has not dropped below the green line (in winter) since December 2015. :o

I can't see any year other than 2016 that has the property of being always above average in DMI 80N (well, there is also 2017 so far..). However I don't have the knowledge to make my speculation worth much if I was to start predicting next winter!
It hasn't dropped to the green line...forget below it (in winter).  It has consistently stopped about five degrees above the previous average.

There has got to be something physical about that even if we have not figured out what or why.
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on February 19, 2017, 04:34:51 PM
Update for the week to February 18th

The current 5 day trailing average is on 14,238,000km2 while the 1 day extent is at 14,304,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,091,000km2, a decrease from -1,312,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -330,000km2, a decrease from -441,000km2 last week. We're currently 2nd lowest on record, down from lowest last week.

(http://i.imgur.com/DfpPwuj.png)

The average daily change over the last 7 days was +49.0k/day, compared to the long term average of +17.4k/day, and the 07, 11 and 12 average of +33.3k/day.
The average long term change over the next week is +19.0k/day, with the 07, 11, and 12 average being +12.1k/day.

(http://i.imgur.com/6vAaB7G.png)

The extent increase so far this February is the 13th largest on record. To achieve the largest increase, a gain of at least 29.8k/day is required (at least +29.1k/day with with single day values), while the smallest increase requires a loss of at least 45.3k/day (loss of at least 64.8k/day with single day values) and an average increase requires a gain of 2.8k/day (loss of 4.7k/day with single day values).

(http://i.imgur.com/GixOf4f.png)
Title: Re: 2017 sea ice area and extent data
Post by: Tor Bejnar on February 19, 2017, 11:52:22 PM
BFTV's weekly summaries, especially the one showing the relatively extreme ups and downs of daily ice growth (over the course of several days), makes it clear to me that making weekly projections based on last week's extent and area growth numbers is a fool's errand.  It seems a best guess for growth over a week's time would be made by using the 30-year average for this time of year than using last week's or any few year's average, even though we are in record or near-record extent (and area) territory. 

So thank you very much BFTV.

Some, of course, are paying attention to weather and weather forecasts, and making forecasts of ice growth on these.  (I don't have the knowledge or skills to do this [nor patience, yet, to learn].)
Title: Re: 2017 sea ice area and extent data
Post by: Jim Pettit on February 22, 2017, 02:52:12 PM
NSIDC extent has plateaued a bit after last week's robust gains, and is still running far below (>2 standard deviations) the long-term mean.

(http://iwantsomeproof.com/extimg/sie_nsidc_daily_for_selected_years.png)

In the meantime. despite those recent increases, NSIDC's 2017-to-date average is substantially lower than all previous years:

(http://iwantsomeproof.com/extimg/sie_nsidc_ytd_anomalies.png)

If the remainder of the 2017 refreeze season were to duplicate the average behavior of the last ten years (2007-2016), this year's maximum would be a new record low one of 14.498M km2, and it would occur on 17 March.

(http://iwantsomeproof.com/extimg/sie_nsidc_projections_from_current_date.png)
Title: Re: 2017 sea ice area and extent data
Post by: Jim Hunt on February 22, 2017, 03:06:44 PM
NSIDC extent has plateaued a bit after last week's robust gains, and is still running far below (>2 standard deviations) the long-term mean.


I have even begun to wonder if the 2017 extent maximum might be around here somewhere:

http://GreatWhiteCon.info/2017/02/the-2017-arctic-sea-ice-maximum-extent/ (http://GreatWhiteCon.info/2017/02/the-2017-arctic-sea-ice-maximum-extent/)

Crow pie time RSN?
Title: Re: 2017 sea ice area and extent data
Post by: Jim Pettit on February 22, 2017, 07:44:13 PM
I have even begun to wonder if the 2017 extent maximum might be around here somewhere:

[url]http://GreatWhiteCon.info/2017/02/the-2017-arctic-sea-ice-maximum-extent/[/url] ([url]http://GreatWhiteCon.info/2017/02/the-2017-arctic-sea-ice-maximum-extent/[/url])

Crow pie time RSN?


I wouldn't place any bets at the moment, but it's certainly possible. A few previous years had already seen their maximum by this daye, and several more occur in the next week, including 2007 and 2016. (The latest maximum in recent years was 2010's March 31 peak. That's still five and a half weeks away.
Title: Re: 2017 sea ice area and extent data
Post by: Jim Hunt on February 23, 2017, 12:42:45 PM
I wouldn't place any bets at the moment, but it's certainly possible.

No crow pie consumed yet!
Title: Re: 2017 sea ice area and extent data
Post by: DrTskoul on February 23, 2017, 12:46:24 PM
I wouldn't place any bets at the moment, but it's certainly possible.

No crow pie consumed yet!

Admit it. You must really like crow. Every year you prepare it early ...  ;D ;D ;D
Title: Re: 2017 sea ice area and extent data
Post by: Jim Hunt on February 24, 2017, 10:27:58 AM
Admit it. You must really like crow.


Actually last year, with a little help from Wipneus, my alter ego's prognosticatory powers proved to be astonishingly accurate:

http://GreatWhiteCon.info/2016/02/the-2016-arctic-winter-sea-ice-puzzle/#comment-213898 (http://GreatWhiteCon.info/2016/02/the-2016-arctic-winter-sea-ice-puzzle/#comment-213898)

Scoff at this @shubclimate. 2016 maximum CT Arctic sea ice area will be ~12.886 million square kilometers


Getting back to this year, can I be excused my customary crow consumption for another day at least? UH AMSR2 extent is just above the prior high today, but area is still just below it.
Title: Re: 2017 sea ice area and extent data
Post by: DrTskoul on February 24, 2017, 12:24:05 PM
 ;D 8)
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on February 26, 2017, 08:13:23 PM
Update for the week to February 25th

The current 5 day trailing average is on 14,360,000km2 while the 1 day extent is at 14,362,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,102,000km2, an increase from -1,091,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -293,000km2, a decrease from -330,000km2 last week. We're currently 3rd lowest on record, down from 2nd lowest last week.

(http://i.imgur.com/QEXgx7I.png)

The average daily change over the last 7 days was +17.4k/day, compared to the long term average of +19.0k/day, and the 07, 11 and 12 average of +12.1k/day.
The average long term change over the next week is +5.9k/day, with the 07, 11, and 12 average being +19.0k/day.

(http://i.imgur.com/WgOjNSe.png)

The extent increase so far this February is the 12th largest on record. To achieve the largest increase, a gain of at least 58.8k/day is required (at least +146.4k/day with with single day values), while the smallest increase requires a loss of at least 191.4k/day (loss of at least 478.9k/day with single day values) and an average increase requires a loss of 31.1k/day (loss of 78.8k/day with single day values)

(http://i.imgur.com/TxyRmlV.png)
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on March 01, 2017, 02:21:20 PM
Some melting may have started, but how about the Arctic Basin where almost all the remaining ice will have retreated by the time of the minimum?

Attached are detailed graphs of the maximum of area and extent in the Arctic Basin, taken to be Beaufort, Chukchi, East Siberian, Laptev and Central Basin regions.
Included in the graphs is the 10%-90% percentiles range calculated in the 1981-2010 era.

What can be seen:
- through the noise it is clear that the normal date that the maximum in the Basin is reached is in the beginning of April.
- at maximum, less than a handful of years do not reach 100% ice extent.
- 2017 is currently no longer running very low and is more or less found in the middle of the pack.

 
Title: Re: 2017 sea ice area and extent data
Post by: Tor Bejnar on March 01, 2017, 03:16:53 PM
...
What can be seen:
- through the noise it is clear that the normal date that the maximum in the Basin is reached is in the beginning of April.
- at maximum, less than a handful of years do not reach 100% ice extent.
- 2017 is currently no longer running very low and is more or less found in the middle of the pack.
Thanks for this reality check.  My reading of the second chart says every year has reached 100% extent at some point in April (at least) for the "Arctic Basin".  2017 reached 100% extent coverage briefly already. 

I'm sure there is a deficit of ice volume in the Arctic Basin (but this is OT  :-X).
Title: Re: 2017 sea ice area and extent data
Post by: Shared Humanity on March 01, 2017, 03:27:50 PM
The minimum last year was very low and the ice was in horrible condition. This freeze season has been weak, arguably the weakest on record with FDD anomaly that is unbelievable. I would expect that this tendency to reach 100% extent in the Arctic Basin will persist for many years and it would be a great metric to track as it would capture so many changes occurring in the basin. (halocline destruction, increased wave activity due to open water, rapidly growing high humidity environment, ice mobility, etc)
Title: Re: 2017 sea ice area and extent data
Post by: Jim Hunt on March 05, 2017, 11:12:22 AM
I fear crow is now on my menu:

http://GreatWhiteCon.info/2017/03/facts-about-the-arctic-in-march-2017/ (http://GreatWhiteCon.info/2017/03/facts-about-the-arctic-in-march-2017/)

There's unfortunately no avoiding the fact that UH AMSR2 area has posted a new high for the year at a smidgen over 13 million square kilometers:

Title: Re: 2017 sea ice area and extent data
Post by: wili on March 05, 2017, 12:03:10 PM
Apologies if this has been posted already somewhere and if this is not the right spot for it:

http://www.zmescience.com/ecology/climate/arctic-ice-aerosols/?utm_source=ZME+Science+Newsletter&utm_campaign=5f37c44652-ZME_Science_Daily3_6_2015&utm_medium=email&utm_term=0_3b5aad2288-5f37c44652-242645473&ct=t(ZME_Science_Daily11_8_2014) (http://www.zmescience.com/ecology/climate/arctic-ice-aerosols/?utm_source=ZME+Science+Newsletter&utm_campaign=5f37c44652-ZME_Science_Daily3_6_2015&utm_medium=email&utm_term=0_3b5aad2288-5f37c44652-242645473&ct=t(ZME_Science_Daily11_8_2014))

Aerosol emissions kept climate change in check over the Arctic until Clean Air regulations

Researchers first observed that Arctic ice cover was dwindling in the mid-1970s, and some climate model simulations done since then show that ice loss may have begun as early as 1950. But recently recovered Soviet observations show that between 1950 and 1975, Arctic ice cover actually increased for almost as much as it’s decreased between 1975 to 2005. Which doesn’t fit into our models in any way.

A new study aimed at uncovering the cause behind this expansion found that human-made air pollution is also to blame here. The paper proposes that [p]articles originating primarily from the burning of fossil fuels may have temporarily overshadowed the effects of global warming in the third quarter of the 20th century in the eastern Arctic.
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on March 05, 2017, 05:53:48 PM
Update for the week to March 4th

The current 5 day trailing average is on 14,377,000km2 while the 1 day extent is at 14,437,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,127,000km2, an increase from -1,102,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -410,000km2, an increase from -293,000km2 last week. We're currently lowest on record, up from 3rd lowest last week.

(http://i.imgur.com/oUzlUnD.png)

The average daily change over the last 7 days was +2.2k/day, compared to the long term average of +5.9k/day, and the 07, 11 and 12 average of +19.0k/day.
The average long term change over the next week is -0.1k/day, with the 07, 11, and 12 average being +9.3k/day

(http://i.imgur.com/Bwnx4rr.png)

The extent change so far this March is the 15th most positive record. To achieve the largest increase, a gain of at least 13.9k/day is required (at least +12.6k/day with with single day values), while the largest drop requires a loss of at least 27.1k/day (loss of at least 31.9k/day with single day values) and an average change requires a loss of 9.1k/day (loss of 12.3k/day with single day values).

(http://i.imgur.com/Syjh3nj.png)

The extent increase in February was the 19th smallest on record while the average extent was the lowest on record.

(http://i.imgur.com/AuN1c34.png)

(http://i.imgur.com/WqoFNhe.png)
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on March 12, 2017, 05:12:35 PM
Update for the week to March 11th

The current 5 day trailing average is on 14,354,000km2 while the 1 day extent is at 14,420,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,148,000km2, an increase from -1,127,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -498,000km2, an increase from -410,000km2 last week. We're currently 2nd lowest on record, down from lowest last week.

(http://i.imgur.com/buHHHgI.png)

The average daily change over the last 7 days was -3.1k/day, compared to the long term average of -0.1k/day, and the 07, 11 and 12 average of +9.3k/day.
The average long term change over the next week is -7.1k/day, with the 07, 11, and 12 average being -4.8k/day

(http://i.imgur.com/0kvXzc8.png)

The extent change so far this March is the 15th most positive record. To achieve the largest increase, a gain of at least 19.7k/day is required (at least +18.3k/day with with single day values), while the largest drop requires a loss of at least 35.4k/day (loss of at least 43.1k/day with single day values) and an average change requires a loss of 11.1k/day (loss of 16.0k/day with single day values).

(http://i.imgur.com/I3ncKjv.png)
Title: Re: 2017 sea ice area and extent data
Post by: Tor Bejnar on March 20, 2017, 04:34:32 AM
BFTV: where are you? I have an addiction to your wonderful weekly summaries, and now I'm going into withdrawals.  'Trust you're just busy!
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on March 22, 2017, 04:59:38 PM
Area from NSIDC sea ice concentration data is again lowest for the day.
Title: Re: 2017 sea ice area and extent data
Post by: Pmt111500 on March 22, 2017, 07:07:12 PM
Thank you Wipneus for the graph, it'll be interesting to see if the curve follows the 2016 line for the next 3 months. It almost looks like something broke the previous winter 2016 february to april since the unique form of the curve late april to midsummer.
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on March 22, 2017, 08:38:40 PM
Update for the week to March 18th (finally!)

The current 5 day trailing average is on 14,305,000km2 while the 1 day extent is at 14,178,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,148,000km2, the same as last week. The anomaly compared to the 07, 11 and 12 average is at -506,000km2, an increase from -498,000km2 last week. We're currently lowest on record, up from 2nd lowest last week.

(http://i.imgur.com/sJrumIV.png)

The average daily change over the last 7 days was -7.0k/day, compared to the long term average of -7.1k/day, and the 07, 11 and 12 average of -4.8k/day.
The average long term change over the next week is -12.3k/day, with the 07, 11, and 12 average being -18.5k/day.

(http://i.imgur.com/vjcJPXk.png)

The extent change so far this March is the 19th least negative record. To achieve the largest increase, a gain of at least 34.1k/day is required (at least +52.0k/day with with single day values), while the largest drop requires a loss of at least 50.6k/day (loss of at least 48.4k/day with single day values) and an average change requires a loss of 13.3k/day (loss of 4.2k/day with single day values).

(http://i.imgur.com/V98JgmA.png)
Title: Re: 2017 sea ice area and extent data
Post by: Jim Pettit on March 23, 2017, 03:29:31 PM
I've added a new graph to my stable, this one plotting year-to-date NSIDC SIE extent anomalies for the current year, alongside the ten previous years with the lowest average annual anomalies, plus decadal average lines for the 80s,90s, and 00s:

(http://iwantsomeproof.com/extimg/sie_nsidc_ytd_average_anomalies.png)

This graph does a good job showing just how much more sunlight-absorbing open water there now is during those months with high solar insolation. A few days with less ice-covered water won't change much, obviously, but when that extra sea surface is exposed to the summer sun for months on end, the cumulative effect becomes part of a powerful feedback loop.

A few things really stand out to me:
--the deep 2017 anomaly (red line)
--last year's recordsetting average anomaly (orange)
--2012's wild June-October plunge (violet)

i suspect that 2017 will follow a trajectory similar to last year's through June, then steepen a bit after that through the minimum, though as always there's no way to know. Anyway, you can find it at my climate graphs page (https://sites.google.com/view/pettitclimategraphs), or by the image URL (http://iwantsomeproof.com/extimg/sie_nsidc_ytd_average_anomalies.png).
Title: Re: 2017 sea ice area and extent data
Post by: jai mitchell on March 23, 2017, 04:41:13 PM
thanks Jim, that is very informative
Title: Re: 2017 sea ice area and extent data
Post by: gerontocrat on March 23, 2017, 04:44:15 PM
...... showing just how much more sunlight-absorbing open water there now is during those months with high solar insolation. A few days with less ice-covered water won't change much, obviously, but when that extra sea surface is exposed to the summer sun for months on end, the cumulative effect becomes part of a powerful feedback loop.


There is nearly 2 million sq km more open water as of now compared with the 1980's. Being at the fringes of the ice-cap meaningful insolation is already happening on that water. I wonder what is the accumulated  additional heat still in long-term storage in the ocean due to increased insolation caused by reduction in sea-ice area  spatially distributed over the Arctic year by year since 1979.
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on March 26, 2017, 04:21:14 PM
Update for the week to March 25th

The current 5 day trailing average is on 14,111,000km2 while the 1 day extent is at 14,073,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,255,000km2, an increase from -1,148,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -570,000km2, an increase from -506,000km2 last week. We're currently lowest on record, the same as last week.

(http://i.imgur.com/y4EVbUi.png)

The average daily change over the last 7 days was -27.7k/day, compared to the long term average of -12.3k/day, and the 07, 11 and 12 average of -18.5k/day.
The average long term change over the next week is -12.1k/day, with the 07, 11, and 12 average being -5.3k/day.

(http://i.imgur.com/Q0bKuXW.png)

The extent change so far this March is the 16th most negative record. To achieve the largest increase, a gain of at least 106.4k/day is required (at least +168.9k/day with with single day values), while the largest drop requires a loss of at least 77.4k/day (loss of at least 106.6k/day with single day values) and an average change requires an increase of 3.4k/day (+14.6k/day with single day values).

(http://i.imgur.com/wXzDDuA.png)
Title: Re: 2017 sea ice area and extent data
Post by: Tor Bejnar on March 26, 2017, 08:09:18 PM
... the largest drop requires a loss of at least 77.4k/day (loss of at least 106.6k/day with single day values) ...
Normally I'd say such a rate of loss would be impossible, but I see that in 1979 the rate of loss was nearly this high.  Of course, there was much more southern ice available to melt back then (but less CO2 and H2O [and probably methane] in the Arctic air).

I want to express my continued profound appreciation to BFTV for posting these summaries.
Title: Re: 2017 sea ice area and extent data
Post by: Neven on March 27, 2017, 09:06:26 PM
Here's a comment Buddy posted in the wrong thread:

Below is Wip's graphic of COMBINED global sea ice area.  I love Wip's graphic for several reasons....but certainly one of the reasons is that it combines the sea ice and we can see where we are IN TOTAL.  For albedo....and other reasons....that is important.

Global warming over the last few years has been "off the charts" for both sea ice, ocean temps, and air temperature.  And this year it appears to have been attacking the sea ice in a big way.

I'll describe the "interesting things" that I see/wonder about....when I look at Wip's chart.  Note:  I have added some things to the chart:

(1)  There are 4 "legs" to the trends in global sea ice over a years time....and this is true from 1978 through today:

(A) Leg A....is from early-to-mid November and goes through mid February.  That is when the Antarctic is in PEAK MELT season and is losing ice at a faster rate than the Arctic is gaining ice.

(B) Leg B....is from mid February through mid June.  That is when the Antarctic is adding more ice than the Arctic is losing.

(C) Leg C....is from mid June through end of August/early September.  This is where the Arctic is now in PEAK MELT and losing more ice than the Antarctic is adding.

(D) Leg D...is from end of August/early September through the end of October/early November.  This is when the Arctic is adding more ice than the Antarctic is losing. 


(2)  Prior to 2016.....the "slope" of the two "peaks" in sea ice.....WAS UP as you can see by the upward sloping BLUE LINES.   Before 2016....the highest peak was the "early November peak".....which is the time of year when the Arctic is gaining ice at a fast clip AND when the Antarctic is losing ice at a SLOW CLIP, just before the Antarctic really begins to lose serious ice.

But 2016 changed all of that.  In 2016 two things happened from a "mathematical" standpoint:  (a) the Antarctic ice sheet reached a RECORD LOW MAXIMUM in late August of 2016 which is VERY EARLY, and (b) the Antarctic started losing ice in late August when the Arctic was still losing ice itself.  That combination of LOW MAX and EARLY MAX by the Antarctic.....AND....the Arctic still losing ice....created a RECORD LOW PEAK to global sea ice in early October.  That peak was about 17.5 vs the prior record low peak of 20.5.  That low peak in 2016 was about 15% LESS than the prior record low peak.

In "charting".....whether you're dealing with things in nature....or your dealing with things in "markets" (stock market, oil market, etc).....that is called a "DIVERGENCE".  Something changed or reached a tipping point....in order to cause such an immediate and significant change.

The "FUNDAMENTALS" cause the graph....the graph don't cause the fundamentals.  Did currents in the southern oceans shift to allow a greater amount of warm ocean water to attack the ice?  Did the winds coming from the interior of Antarctica blowing OUT towards the sea die down and decrease the amount of area/extent in Antarctica?

OR.....have we reached ANOTHER TIPPING POINT......where several things have slowly been "coming together" to cause the increased melt earlier in the season:  Record setting air temps over the past 3 years, continually warming ocean temps, changing ocean currents, etc.

The SECOND GRAPH BELOW......is a "stab" at what a "worst case scenario" MIGHT look like over the coming year.  If there are enough FUNDAMENTALS that are now coming together to drive the ice levels LOWER....and EARLIER.  It is NOT meant to be "this is what I think will happen."  It is more of a "what IF another significant low happens THIS YEAR AGAIN".....?  The "blue line" for the remainder of 2017 is just a "what if" scenario.

Also....note the "black circle".....that is just shown to highlight where this years line has CROSSED OVER BELOW the record low of the last year.

I KNOW where the ice is going over the next 10 years....LOWER.  What we don't know is WHEN and HOW STEEP the drop will be.  That SECOND GRAPHIC just posts something to "think about"....and ponder.  If anything CLOSE to that DOES HAPPEN this year....then the ramp up in worry will be significant.....although at this point, I'm not sure just how much more worrying can be done going from a "level 8 worry" to a "level 10 worry".           
Title: Re: 2017 sea ice area and extent data
Post by: Pmt111500 on March 28, 2017, 07:44:50 AM
Well I guess someone had to be the first to speculate on future behavior of Global sea Ice. Thanks Buddy for being the first bold one to spell out the dreaded 't'-word (tipping point).

Some notes.
1) The August 2016 would be very close to the maximum atmospheric effect of El Nino.
2) Large part of the (imo) naturally impossible deviation of last winter (starting from late October) was due to Antarctic ice melting way faster than usual.
3) Thus there could have been a tipping point for some part of Southern Ocean. I remember there was something odd going on on the region of Weddell Gyre.

This would be the Antarctic area to watch this (northern) spring. Has the Antarctic Circumpolar Current moved to an area it's not previously been? Thus the start of the freeze in Antarctic could be abnormal here as well

4) For me, the Arctic lack of growth in the autumn was pretty much what I'd expect of the WACC (and the theory of J. Francis of the diminishing temperature gradient between tropics and arctic).

5) From all of the previous. I'm not even sure we'll even see the first peak of the global graph clearly. The global graph could flat line all through this summer starting from June as the Siberian melt progresses.

An extreme scenario, but on these days they're necessary to be aware of.  Knowing you're much into politics, Buddy, I'm still of the opinion that Russians as people (and especially Siberian Russians) do not much care if their winters get milder. They might get a couple of ten millions of immigrants from south at some point, but that's an issue for the time it happens.

I'm keeping an eye on the spring progress during this post-El Nino year. I think the more pronounced swings in the extent and area of Arctic Sea ice since 2006 allows the speculations of general tipping points, but  for now i'm thinking these more of a local issue. As the weather gets stuck in one position more easily these days, the serious hobbyist of atmospheric science in me could say, the weather induced events unfolding round the northern hemisphere are of note and interest. I'm rather looking forward the time the idjit possessing The Button and his so called
friends get it. Not too much though, as their other views are also quite repulsive.
Title: Re: 2017 sea ice area and extent data
Post by: Jim Pettit on April 01, 2017, 03:26:42 PM
NSIDC finished the month back in first place for the day, the month, and the year-to-date. In fact, for the fifth consecutive month--that is, beginning with November-- NSIDC extent has been the lowest monthly average on record, and that's even with the slowdown in extent loss we've seen over the past week. A few helpful graphs:

(http://iwantsomeproof.com/extimg/sie_nsidc_monthly_average.png)

(http://iwantsomeproof.com/extimg/sie_nsidc_ytd_average_anomalies.png)

(http://iwantsomeproof.com/extimg/sie_nsidc_daily_for_selected_years.png)
Title: Re: 2017 sea ice area and extent data
Post by: johnm33 on April 01, 2017, 05:21:55 PM
Looking at the extent graph above, and at Wipneus's Global sea ice, we're about two weeks away from a new downturn in ice cover, it's happened twice that's coincidence a third time will be a trend.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on April 02, 2017, 02:21:00 PM
Arctic Basin ice area ( total of Beaufort, Chukchi, East Siberian, Laptev and Central Basin regions) calculated from NSIDC sea ice concentration has reached a new maximum for this year. As discussed previously perfectly normal. Extent has been at 100% for a while.
Now waiting for the melting season to start.
Title: Re: 2017 sea ice area and extent data
Post by: Shared Humanity on April 02, 2017, 04:59:03 PM
The Arctic Basin SIA chart is somewhat encouraging as it clearly shows the basin is in better shape than last year and has been for about 6 weeks. Maybe this has allowed the ice to strengthen relative to 2016 despite the FDD anomaly.
Title: Re: 2017 sea ice area and extent data
Post by: Jim Pettit on April 02, 2017, 05:54:21 PM
The Arctic Basin SIA chart is somewhat encouraging as it clearly shows the basin is in better shape than last year and has been for about 6 weeks. Maybe this has allowed the ice to strengthen relative to 2016 despite the FDD anomaly.

Possibly--though it should be noted that 2012 was smashed against the ceiling for most of the period between late February and early May, and that doesn't appear to have been of much help in avoiding that year's incredibly low minimum...

Again, this should be an "interesting" year...
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on April 02, 2017, 07:10:49 PM
Update for the week to April 1st

The current 5 day trailing average is on 14,167,000km2 while the 1 day extent is at 14,126,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,114,000km2, a decrease from -1,255,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -477,000km2, a decrease from -570,000km2 last week. We're currently lowest on record, the same as last week.

(http://i.imgur.com/MPXgFfO.png)

The average daily change over the last 7 days was +8.0k/day, compared to the long term average of -12.1k/day, and the 07, 11 and 12 average of -5.3k/day.
The average long term change over the next week is -31.5k/day, with the 07, 11, and 12 average being -23.1k/day.

(http://i.imgur.com/d5Cip7L.png)

The extent loss so far this April is the 9th smallest record. To achieve the largest loss, a drop of at least 55.9k/day is required (at least -58.5k/day with with single day values), while the smallest drop requires a loss of less than 24.0k/day (loss of less than 24.2k/day with single day values) and an average loss requires a drop of 38.1k/day (-39.4k/day with single day values).

(http://i.imgur.com/bkFmtdB.png)

The extent change in March was the 16th least negative on record, while the average extent was the lowest on record.

(http://i.imgur.com/YKC4ZzI.png)

(http://i.imgur.com/pTmsgCy.png)
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on April 05, 2017, 02:31:06 PM
Sea ice area calculated for NSIDC sea ice concentration in the Arctic Basin (regions Beaufort, Chukchi, ESS, Laptev and Central Basin) seems to go for a record day max.

It is now at 7.173 Mm2, second behind 4th April 1988: 7.175 Mm2.

Title: Re: 2017 sea ice area and extent data
Post by: Shared Humanity on April 05, 2017, 02:42:56 PM
This basin push towards a max can only be characterized as encouraging, not in the long term but for the approaching melt season. What it is telling us is that the peripheral seas are the main contributors to the low numbers and the variability in these seas is typical of today's Arctic.
Title: Re: 2017 sea ice area and extent data
Post by: Andreas T on April 05, 2017, 03:20:17 PM
Not necessarily encouraging, the lower values last year were mainly due to open water north of Spitsbergen, i.e. higher values now are associated with higher transport out of the basin towards destruction.
The high area mainly means ice is compact, but if that means little movement towards the North Greenland coast where it would build thickness by compaction, it means little growth in volume for the few weeks remaining for build up. The best place to grow ice now is in opening leads while surface temperatures are still cold.
Title: Re: 2017 sea ice area and extent data
Post by: magnamentis on April 05, 2017, 10:50:25 PM
This basin push towards a max can only be characterized as encouraging, not in the long term but for the approaching melt season. What it is telling us is that the peripheral seas are the main contributors to the low numbers and the variability in these seas is typical of today's Arctic.

too much cherry picking IMO, this kind of information is fodder for deniers to interpret it their way. no offense meant, after all it's a simple statement of facts as we know them while i'm not entirely sure whether area and extent still hold too much value as information to describe the state of the ice. the more i read and look at graphs and plots based on old models, based on how it once was, the more i get the feeling that something is not right, i just hope that we won't get too much of a negative surprise if what we got by now wouldn't be bad enough already.

thanks for all the contributions from both of you but still i felt that i have to make that statement, hope it's well taken, because the other side (deniers) are very strategical at times and perhaps we as well need to be a bit smartly using the available input (staying with the borders of truth and/or best knowledge of course)
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on April 07, 2017, 03:24:58 PM
... i felt that i have to make that statement, hope it's well taken, because the other side (deniers) are very strategical at times and perhaps we as well need to be a bit smartly using the available input (staying with the borders of truth and/or best knowledge of course)

On the contrary, this makes me very unhappy.

It is bad enough that staying on-topic seems to be less and less respected by a very loud minority.

But being criticized for being on-topic but not being political correct in a pure sea ice thread is a step too far. Please discuss that somewhere else, I am not interested.

The subject here is "2017 sea ice area and extent data", how hard is it to stay with that?
Title: Re: 2017 sea ice area and extent data
Post by: jai mitchell on April 07, 2017, 04:13:25 PM
I think that the high basin Sea Ice Area this year is extremely interesting considering record low NSIDC sea ice extent and PIOMAS volume. 

It makes me consider the potential impacts of increased sea ice mobility, recent extreme cold (compared to the previous two winters) and the likelihood of changes in dominant wind patterns under the changing regime.

very useful and informative, cause for pause and deep thought.

thank you!
Title: Re: 2017 sea ice area and extent data
Post by: Neven on April 07, 2017, 04:21:32 PM
On the contrary, this makes me very unhappy.

It is bad enough that staying on-topic seems to be less and less respected by a very loud minority.

But being criticized for being on-topic but not being political correct in a pure sea ice thread is a step too far. Please discuss that somewhere else, I am not interested.

The subject here is "2017 sea ice area and extent data", how hard is it to stay with that?

I agree, and would like to add: F*** climate risk deniers and how they may twist words on some obscure Forum.
Title: Re: 2017 sea ice area and extent data
Post by: gerontocrat on April 07, 2017, 04:27:05 PM
Dear Neven,
I have to inform you that due to the activities of persons including me this obscure blog is not as obscure as once it was (and nor is your typepad).
Sorry,
Gerontocrat.
Title: Re: 2017 sea ice area and extent data
Post by: magnamentis on April 07, 2017, 05:34:21 PM
On the contrary, this makes me very unhappy.

It is bad enough that staying on-topic seems to be less and less respected by a very loud minority.

But being criticized for being on-topic but not being political correct in a pure sea ice thread is a step too far. Please discuss that somewhere else, I am not interested.

The subject here is "2017 sea ice area and extent data", how hard is it to stay with that?

I agree, and would like to add: F*** climate risk deniers and how they may twist words on some obscure Forum.

duly noted including the general opinion that it does not matter (ref to f... them) it's a valid possible point of view and hence i'll try to remember. didn't mean to make anyone unhappy ;)
Title: Re: 2017 sea ice area and extent data
Post by: Tor Bejnar on April 07, 2017, 06:13:09 PM
I'm curious about the effect Nares Strait is having on Baffin Bay.  Specifically, Kane Basin (and the entire Strait) has not had an effective ice arch all winter, so Nares has exported a lot of up-to-about-one-meter-thick (grown in Nares Strait) ice.  The volume (not thickness) of ice created in Nares Strait will be much greater than usual, as new ice with no snow cover is (virtually) continually being created in the northern parts of the Strait, and the first 10 or 50 cm grows much faster (in a given temperature) than the third.  And it is almost constantly being exported to Baffin Bay.  Other years, Nares Strait closes in January or February and gets flushed out in June. Thicker, obviously, but after a great deal of melting happens further south, and nowhere near as much ice area gets exported, in total.
Baffin/Newfoundland Bay Area from Regional Graphs page (https://sites.google.com/site/arcticseaicegraphs/regional):
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on April 08, 2017, 08:18:19 AM
Meanwhile, commenter Al Roger reported on the blog (http://neven1.typepad.com/blog/2017/04/piomas-april-2017.html?cid=6a0133f03a1e37970b01bb098deb05970d#comment-6a0133f03a1e37970b01bb098deb05970d) that NSIDC has decided to change the counter-intuitive way average monthly extent numbers are calculated:

And with all that, NSIDC inform me:-
“We have received similar questions in the recent past about our December numbers, and the science leads have decided to switch the way in which the averaging is completed. The current method is really just a legacy way of doing things as the dataset's original intended purpose was to simply produce coarse resolution figures (c.a. 2007) on a monthly interval for our site. The dataset is now clearly the most popular product we have due to our blog-style publication and thus changes will be made after considering any impact to the community.“


So expect the monthly extent numbers to drop in the near future (Al shows some numbers).
Title: Re: 2017 sea ice area and extent data
Post by: TerryM on April 08, 2017, 10:05:29 AM
Wip


Will there be a means of converting from the new numbers to the legacy numbers?


Thanks
Terry
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on April 08, 2017, 02:49:46 PM
Wip


Will there be a means of converting from the new numbers to the legacy numbers?


Thanks
Terry

We have to wait what the NSIDC says when they introduce the change. Perhaps some average difference (for the month of year) can be given.

Remember that the problem is that the current (legacy) way is to average concentration first and from that extent. For a grid cell 5 days of ice cover is enough to exceed the 15% and the cell is included for the full 100%. The grid cell in the new way will be counted as about 16% (5 divided by number of days in the month). The net difference will obviously depend a lot on the particular dynamics in sea ice in that particular month.
Title: Re: 2017 sea ice area and extent data
Post by: Lord M Vader on April 08, 2017, 02:54:02 PM
Wipneus: will you produce daily and forecasted numbers from NSIDC values?
Title: Re: 2017 sea ice area and extent data
Post by: Shared Humanity on April 08, 2017, 05:43:16 PM

On the contrary, this makes me very unhappy.

It is bad enough that staying on-topic seems to be less and less respected by a very loud minority.

But being criticized for being on-topic but not being political correct in a pure sea ice thread is a step too far. Please discuss that somewhere else, I am not interested.

The subject here is "2017 sea ice area and extent data", how hard is it to stay with that?

While I do not know what was said as I blocked this commenter a while back, I want to thank you for this.
Title: Re: 2017 sea ice area and extent data
Post by: Shared Humanity on April 08, 2017, 05:48:21 PM
Meanwhile, commenter Al Roger reported on the blog ([url]http://neven1.typepad.com/blog/2017/04/piomas-april-2017.html?cid=6a0133f03a1e37970b01bb098deb05970d#comment-6a0133f03a1e37970b01bb098deb05970d[/url]) that NSIDC has decided to change the counter-intuitive way average monthly extent numbers are calculated:

And with all that, NSIDC inform me:-
“We have received similar questions in the recent past about our December numbers, and the science leads have decided to switch the way in which the averaging is completed. The current method is really just a legacy way of doing things as the dataset's original intended purpose was to simply produce coarse resolution figures (c.a. 2007) on a monthly interval for our site. The dataset is now clearly the most popular product we have due to our blog-style publication and thus changes will be made after considering any impact to the community.“


So expect the monthly extent numbers to drop in the near future (Al shows some numbers).


What I find most awesome about this response is their reference to the "community". There is a growing community (including this blog) of actively engaged persons on the planet. I draw comfort that it exists and is being recognized.
Title: Re: 2017 sea ice area and extent data
Post by: TerryM on April 08, 2017, 11:41:42 PM

Wip

It sounds as though NSIDC's new method will be a huge improvement, but unless they run their figures back there will be a huge gap with little connecting the new data to the historic.
A comparison between where we are and where we were in 1979, or 2007, or even 2012 might be lost forever.
Perhaps publishing parallel charts for a few seasons would ameliorate the situation?


Is it possible for you to provide such a comparison, or will the needed data either not be available, or require so much massaging as to make this impracticable. It's not my intent to add to the huge effort you already expend on our behalf.


 Thanks
 Terry
Title: Re: 2017 sea ice area and extent data
Post by: oren on April 09, 2017, 12:13:46 AM
Terry, I think/hope NSIDC would somehow provide the average for all past years as well. The major strength of NSIDC data is its long record that enables good comparisons. I'm quite sure they are aware of it.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on April 09, 2017, 08:32:09 AM
Wipneus: will you produce daily and forecasted numbers from NSIDC values?

I am not sure what you are asking. NH NSIDC area/extent data are found at the following links (daily updated when NSIDC releases SIC data):

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

In the SH the links are:

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

What "forecasted numbers" and why do you think that I can produce them?



Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on April 09, 2017, 08:37:09 AM

It sounds as though NSIDC's new method will be a huge improvement, but unless they run their figures back there will be a huge gap with little connecting the new data to the historic.
A comparison between where we are and where we were in 1979, or 2007, or even 2012 might be lost forever.
Perhaps publishing parallel charts for a few seasons would ameliorate the situation?

Hi Terry,

I fully expect that NSIDC will replace the complete (1978-present) monthly data series by the updated one. If not I will.

Not sure if they will archive the old data, so perhaps this is the time to do so (reminder to myself).
Title: Re: 2017 sea ice area and extent data
Post by: Lord M Vader on April 09, 2017, 10:33:53 AM
Wipneus: I was thinking about these for example CT-area numbers that you posted quite regularly during the melting season last year.  :)

http://forum.arctic-sea-ice.net/index.php/topic,1457.msg87403.html#msg87403 (http://forum.arctic-sea-ice.net/index.php/topic,1457.msg87403.html#msg87403)

Best regards, LMV
Title: Re: 2017 sea ice area and extent data
Post by: Neven on April 09, 2017, 11:28:58 AM
I know I said they should be ignored, but will this adjustment give climate risk deniers something to shout about? For instance, if later years get revised downwards more than earlier years. The whole reason for adjusting seems complicated enough for some nice spin.
Title: Re: 2017 sea ice area and extent data
Post by: oren on April 09, 2017, 12:12:14 PM
I know I said they should be ignored, but will this adjustment give climate risk deniers something to shout about?
Of course it will, but science should continue in spite of that. It's like living with a psychotic person, even when you are perfect you always seem to fail and blame yourself. At some point you must realise you should be true to yourself.
Title: Re: 2017 sea ice area and extent data
Post by: Neven on April 09, 2017, 12:16:52 PM
I'm not talking about blaming anyone, and climate risk deniers will do as they always will, but I was just wondering if they might get some traction with this. The Lord knows they need some Arctic propaganda to stall the inevitable.
Title: Re: 2017 sea ice area and extent data
Post by: LRC1962 on April 09, 2017, 02:51:40 PM
I'm not talking about blaming anyone, and climate risk deniers will do as they always will, but I was just wondering if they might get some traction with this. The Lord knows they need some Arctic propaganda to stall the inevitable.
Any time when scientists start talking about probabilities, even among those at odds among their peer group, unless you are deadly accurate in your predictions, you are leaving yourself open to ridicule. A case in point was Einstein's theory of General Relativity.   The only way it could then be tested was to get a precise measurement of deflection of light  from a star around the sun. Took years to get that measurement for proof and finally got the proof he needed.
As for measurements today? you are relying on satellite data that is still primarily 2d and getting data only during a passover, unlike what you can get on geostationary equatorial stations. As satelittes improve and get better data then can update old data basing it on old data you will get changes. Problem is that unless you can and care to understand the math involved, you will never truely believe that the science is good.
Title: Re: 2017 sea ice area and extent data
Post by: Shared Humanity on April 09, 2017, 03:31:05 PM
I know I said they should be ignored, but will this adjustment give climate risk deniers something to shout about? For instance, if later years get revised downwards more than earlier years. The whole reason for adjusting seems complicated enough for some nice spin.

Climategate 3 or 4 or whatever. How difficult would it be for them to generate both metrics simultaneously for a couple of years? This way we could still track long term trends by looking at the existing metric while evaluating the effectiveness of the change in capturing what has really been going on.
Title: Re: 2017 sea ice area and extent data
Post by: gerontocrat on April 09, 2017, 03:41:23 PM
"Facts are stubborn things; and whatever may be our wishes, our inclinations, or the dictates of our passions, they cannot alter the state of facts and evidence."     John Adams

"Publish and be damned".   Lord Wellington
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on April 09, 2017, 07:02:28 PM
Update for the week to April 8th

The current 5 day trailing average is on 14,090,000km2 while the 1 day extent is at 13,995,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -970,000km2, a decrease from -1,114,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -392,000km2, a decrease from -477,000km2 last week. We're currently 3rd lowest on record, down from lowest last week.

(http://i.imgur.com/I9WEOZ7.png)

The average daily change over the last 7 days was -10.9k/day, compared to the long term average of -31.5k/day, and the 07, 11 and 12 average of -23.1k/day.
The average long term change over the next week is -39.6k/day, with the 07, 11, and 12 average being -31.4k/day.

(http://i.imgur.com/XTLRD9m.png)

The extent loss so far this April is the 6th smallest record. To achieve the largest loss, a drop of at least 73.1k/day is required (over -72.3k/day with with single day values), while the smallest drop requires a loss of less than 31.0k/day (loss less than 26.1k/day with single day values) and an average loss requires a drop of 49.7k/day (-46.7k/day with single day values).

(http://i.imgur.com/c85Oi3w.png)
Title: Re: 2017 sea ice area and extent data
Post by: Jim Pettit on April 10, 2017, 03:06:15 PM
In not earth-shattering but nonetheless interesting news, NSIDC extent has experienced back-to-back century drops. That's a fairly rare thing so early in the season; it hasn't happened prior to April 10 since 2004. 2016 is now just 5k behind 2016, and should retake first place in the next few days, at least for awhile.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on April 10, 2017, 03:39:09 PM
Wipneus: I was thinking about these for example CT-area numbers that you posted quite regularly during the melting season last year.  :)

[url]http://forum.arctic-sea-ice.net/index.php/topic,1457.msg87403.html#msg87403[/url] ([url]http://forum.arctic-sea-ice.net/index.php/topic,1457.msg87403.html#msg87403[/url])

Best regards, LMV


Because the Cryosphere Today seems to have stopped for good, and there is a better alternative: my NSIDC area, I decided to stop the CT area calculation.

Remember that CT-area is calculated from the same source, NSIDC sea ice concentration but with some differences that make direct comparison with NSIDC extent impossible.

- not taking the true grid cell area in account;
- including lake ice;
- no revisions when the input data (sea ice concentration) is revised;
- not making a 15% cutoff;

On my side it would not be a big deal to restart the CT calculation again, but in my opinion the confusion would not make it worth it (unless CT comes back again).
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on April 15, 2017, 12:41:13 PM
Kevin Pluck created a wonderful video with animated NSIDC sea ice extent, SH, NH and Global.

Link to the video (https://gfycat.com/ImmediateImportantIndigobunting)

More of Kevin's work here (https://imgur.com/user/kevpluck/submitted)
Title: Re: 2017 sea ice area and extent data
Post by: TerryM on April 15, 2017, 04:00:27 PM
Jesus H Christ !


Terry
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on April 16, 2017, 03:23:00 PM
Update for the week to April 15th

The current 5 day trailing average is on 13,817,000km2 while the 1 day extent is at 13,739,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -966,000km2, a decrease from -970,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -445,000km2, an increase from -392,000km2 last week. We're currently lowest on record, up from 3rd lowest last week.

(http://i.imgur.com/f8TEbWX.png)

The average daily change over the last 7 days was -38.9k/day, compared to the long term average of -39.6k/day, and the 07, 11 and 12 average of -31.4k/day.
The average long term change over the next week is -37.3k/day, with the 07, 11, and 12 average being -22.8k/day.

(http://i.imgur.com/68iTsAB.png)

The extent loss so far this April is the 12th smallest record. To achieve the largest loss, a drop of at least 84.6k/day is required (more than -91.6k/day with with single day values), while the smallest drop requires a loss of less than 23.0k/day (less than 20.5k/day with single day values) and an average loss requires a drop of 50.4k/day (-52.1k/day with single day values).

(http://i.imgur.com/r5ixzOj.png)
Title: Re: 2017 sea ice area and extent data
Post by: Juan C. García on April 18, 2017, 02:26:02 AM
I made this graph that shows the number of days on a year, in which the day breaks a record or stays at the second or third lowest.

I would say that it represents the stress that we suffer on a daily basis, wondering what will happen on a particular year.

It is interesting that the worst years are 2005, 2006, 2007 and 2016. Of course, these are for the whole year and in 2012 we didn't have too much days of breaking record, but they happened exactly when they count: at the end of the melting season!
Title: Re: 2017 sea ice area and extent data
Post by: Juan C. García on April 18, 2017, 02:32:48 AM
This is a similar graph, but only looking at the days on the melting season (kind of arbitrary the assignation of days at the melting season).
Title: Re: 2017 sea ice area and extent data
Post by: Juan C. García on April 18, 2017, 03:05:51 AM
To better understand the previous graphs, this is the NSIDC graph for 2005 and previous years. So it is easy to see that 2005 was breaking records continuously, on a daily basis. Of course, here I don't show 2006, but 2006 broke several records of 2005. And so on, year after year.
Title: Re: 2017 sea ice area and extent data
Post by: gerontocrat on April 21, 2017, 01:36:36 PM
Hullo Juan,

I have highlighted a bit of your post which I think I disagree with. Yes, I am being picky.

It is interesting that the worst years are 2005, 2006, 2007 and 2016. Of course, these are for the whole year and in 2012 we didn't have too much days of breaking record, but they happened exactly when they count: at the end of the melting season!

The 2012 end of season melt could be regarded as least important in 2 ways:-
- early season melt (as in 2016) maximises positive feedback from insolation and from that ocean warming to inhibit winter sea ice growth,
- by late August  / September the sun is heading South and insolation is in rapid decline,
- some of us still think maybe it is only when winter sea ice reduces sufficiently will we see an ice-free summer (though the Jury is still out on that one - 2012 does NOT support that speculation).

I wonder what the graph if it included freezing months only would look like. Is there any correlation between winter sea ice volume maxima and summer minima ? (I bet someone on ASIF has done it).
Title: Re: 2017 sea ice area and extent data
Post by: AndrewB on April 21, 2017, 03:49:21 PM
...
Is there any correlation between winter sea ice volume maxima and summer minima ? (I bet someone on ASIF has done it).
GC,
Sorry to point out the obvious, but there is no need to calculate a statistical correlation between winter sea ice volume maxima and summer minima, because the two are directly related by a simple formula:
summer ice minimum = (previous) winter ice maximum - total spring/summer melt

The evolution of the three interlinked variables over time is completely summarized in the following excellent chart by Jim Pettit:
Title: Re: 2017 sea ice area and extent data
Post by: CognitiveBias on April 21, 2017, 04:08:41 PM
...
Is there any correlation between winter sea ice volume maxima and summer minima ? (I bet someone on ASIF has done it).
GC,
Sorry to point out the obvious, but there is no need to calculate a statistical correlation between winter sea ice volume maxima and summer minima, because the two are directly related by a simple formula:
summer ice minimum = (previous) winter ice maximum - total spring/summer melt

The evolution of the three interlinked variables over time is completely summarized in the following excellent chart by Jim Pettit:

As max trends lower, min also trends lower.  Sounds like a positive correlation to me.   I'm not sure of the value of this statistic, but the 'obvious' dismissal is a bit much.
Title: Re: 2017 sea ice area and extent data
Post by: AndrewB on April 21, 2017, 04:38:48 PM
The obvious refers to the fact that there is not a statistical correlation; while there is actually a straightforward logical and mathematical relation. And the excellent chart makes this relation quite obvious, as does the formula.

It's much like asking if the number of ice creams the iceman has in his truck at the end of the day is statistically correlated with the number of ice creams he had in his truck when he exited the factory in the morning. The obvious answer is that there is no need to work out a statistical correlation because we know exactly that:
ice creams at the end of the day = ice creams in the morning - ice creams sold *

Is it obvious why it's obvious?  ???

* In some rare cases, this relation may not hold true. I would suspect the iceman, not the statistician.  ;)
Title: Re: 2017 sea ice area and extent data
Post by: oren on April 21, 2017, 04:47:24 PM
Indeed there is a relation but the correlation does depend in some cases on the third variable, namely the annual loss. Had there been a 100% correlation between max volume and annual loss, there could be 0% correlation between max and min volume. Indeed this is what will happen when min volume is 0 every year.
In reality though, annual loss remained stable and then even increased as max volume decreased over the years. Therefore min volume, on average, is dropping even faster than max volume.
Title: Re: 2017 sea ice area and extent data
Post by: AndrewB on April 21, 2017, 05:06:46 PM
Indeed there is a relation but the correlation does depend in some cases on the third variable, namely the annual loss. Had there been a 100% correlation between max volume and annual loss, there could be 0% correlation between max and min volume. Indeed this is what will happen when min volume is 0 every year.
...

Indeed, that's the case whenever the iceman sells all the ice creams in his truck.

But the correct analysis is not that there is a 100% correlation between number of ice creams in the truck in the morning and the number of ice creams sold, but quite simply that on that day, the iceman sold all the ice creams he had picked up in the morning.

When x - y =0, you don't say that x is 100% statistically correlated to y, you just say x = y.
Title: Re: 2017 sea ice area and extent data
Post by: Juan C. García on April 21, 2017, 11:19:17 PM
Hullo Juan,

I have highlighted a bit of your post which I think I disagree with. Yes, I am being picky.

It is interesting that the worst years are 2005, 2006, 2007 and 2016. Of course, these are for the whole year and in 2012 we didn't have too much days of breaking record, but they happened exactly when they count: at the end of the melting season!

The 2012 end of season melt could be regarded as least important in 2 ways:-
- early season melt (as in 2016) maximises positive feedback from insolation and from that ocean warming to inhibit winter sea ice growth,
- by late August  / September the sun is heading South and insolation is in rapid decline,
- some of us still think maybe it is only when winter sea ice reduces sufficiently will we see an ice-free summer (though the Jury is still out on that one - 2012 does NOT support that speculation).

I wonder what the graph if it included freezing months only would look like. Is there any correlation between winter sea ice volume maxima and summer minima ? (I bet someone on ASIF has done it).

Hi gerontocrat.

Thank for your comment, but I am not sure that I understand it.

2012 started a little low in January and February, but in March it had an important refreeze. So, the daily records on the first five months were not too many, as you can see on the first graph, that compares 2012 with 2007, 2010 and 2011. Even in April, 2012 was above the 1981-2010 average. The melt in June was important, but the real difference appeared after the Great Arctic Cyclone, on August. So, most of the 2012 daily records happened on the second semester, as you can see on the second graph.

2016 was completely the other way. We have daily records almost the whole year, except for July, September and the first half of October. So, I was expecting a minimum record at 2016 lower than what finally happened. I don’t agree with some conclusions that NSIDC makes public, specifically, that 2016 was the fifth lower year. From my point of view, 2016 should be cataloged as the second or at least the third worst year on record, because that it is what it was, in area, daily extent and volume. But well, that is another story.

2016 had 182 days being the daily lowest (against 1979-2015) and 312 days being among the three lowest on record.
2012 had 125 days being the daily lowest (against 1979-2011) and 211 days being among the three lowest on record.

That is, according to my calculations. I compare the days on the year as NSIDC do on a Charctic graph. That is, I compared day 60 on 2011 with day 60 on 2012. Being 2012 a leap year, the 60th day will be Feb 29, while on 2011 would be March 1st. These is what we visually see on Charctic, but the numbers could change a little, if I erase the feb 29´s and I compare the dates matching for the day on the month.

Regarding your last question, I believe that it is not a rule that the year that has a winter minimum, will have a summer minimum. But surely, even that 2012 does not match that rule, it should help to start with a winter minimum. So yes, I agree that there is a bigger possibility of having an ice-free Arctic, on years like 2015-2017, that the melt season starts with low ice. Specially 2017, that we are starting with the lowest volume on record, according to PIOMAS.
Title: Re: 2017 sea ice area and extent data
Post by: Steven on April 22, 2017, 02:11:41 PM
Is there any correlation between winter sea ice volume maxima and summer minima ?

Using data for 1979-2016,  the correlation between detrended maximum volume and detrended minimum volume is 0.648, which is highly statistically significant (p-value: p < 0.001).

However, this is only true for sea ice volume.  For sea ice extent (rather than volume), the correlation between detrended maxima and detrended minima is very weak.
Title: Re: 2017 sea ice area and extent data
Post by: gerontocrat on April 22, 2017, 02:49:04 PM
Is there any correlation between winter sea ice volume maxima and summer minima ?

Using data for 1979-2016,  the correlation between detrended maximum volume and detrended minimum volume is 0.648, which is highly statistically significant (p-value: p < 0.001).

However, this is only true for sea ice volume.  For sea ice extent (rather than volume), the correlation between detrended maxima and detrended minima is very weak.

Thankyou Steven - bloody marvellous.

And, therefore, is it fair to say that a reduction in winter sea ice maximum volume increases the likelihood of a reduced sea ice volume minimum in the following summer and so on ...... ? (though natural variation, e.g. an unusually warm or unusually cool melting season can overwhelm the signal).

If so, then the April sea ice volume maximum will at least indicate the direction of travel?
Or am I making a cause and effect where none really exists ?

To explain my thought processes, in the risk analyses I have done in many different fields from risk of war, economics, finance, water resources and others, absolute data was often rare. One attempts to identify influences, rank them in +ve and -ve directions and attempt to weight them. From that, take a deep breath and make a forecast and assign probabilities of various future events (and be proved wrong).

Title: Re: 2017 sea ice area and extent data
Post by: AndrewB on April 22, 2017, 03:06:29 PM
Is there any correlation between winter sea ice volume maxima and summer minima ?

Using data for 1979-2016,  the correlation between detrended maximum volume and detrended minimum volume is 0.648, which is highly statistically significant (p-value: p < 0.001).

However, this is only true for sea ice volume.  For sea ice extent (rather than volume), the correlation between detrended maxima and detrended minima is very weak.

Steven, just curious: what correlation coefficient did you calculate and how?
Title: Re: 2017 sea ice area and extent data
Post by: oren on April 22, 2017, 03:13:14 PM
gerontocrat, absolutely. This year's extremely low winter volume makes me expect a record summer min volume even with average melt conditions.
Title: Re: 2017 sea ice area and extent data
Post by: Steven on April 22, 2017, 06:41:47 PM
And, therefore, is it fair to say that a reduction in winter sea ice maximum volume increases the likelihood of a reduced sea ice volume minimum in the following summer and so on ...... ? (though natural variation, e.g. an unusually warm or unusually cool melting season can overwhelm the signal).

Yes, that is fair to say.

The 2017 maximum PIOMAS volume should be about 20.8 thousand km3.  For what it's worth, a simple regression analysis then suggests that this gives an 80 percent chance of a record low minimum volume for September 2017.
Title: Re: 2017 sea ice area and extent data
Post by: gerontocrat on April 23, 2017, 03:59:51 PM
And, therefore, is it fair to say that a reduction in winter sea ice maximum volume increases the likelihood of a reduced sea ice volume minimum in the following summer and so on ...... ? (though natural variation, e.g. an unusually warm or unusually cool melting season can overwhelm the signal).

Yes, that is fair to say.

The 2017 maximum PIOMAS volume should be about 20.8 thousand km3.  For what it's worth, a simple regression analysis then suggests that this gives an 80 percent chance of a record low minimum volume for September 2017.

Thanks again, Steven.
The PIOMAS April analysis should be coming out in about a fortnight. Any chance of you running the correlation and indication for 2017 minimum again when it appears and shoving it onto the PIOMAS thread ?
Title: Re: 2017 sea ice area and extent data
Post by: Bill Fothergill on April 23, 2017, 08:10:31 PM
Is there any correlation between winter sea ice volume maxima and summer minima ?


Using data for 1979-2016,  the correlation between detrended maximum volume and detrended minimum volume is 0.648, which is highly statistically significant (p-value: p < 0.001).

However, this is only true for sea ice volume.  For sea ice extent (rather than volume), the correlation between detrended maxima and detrended minima is very weak.


Thank you Steven. That was a concise and meaningful answer to a perfectly reasonable question.

However, an earlier response to Gerontocrat's question was less helpful.
... Sorry to point out the obvious, but there is no need to calculate a statistical correlation between winter sea ice volume maxima and summer minima, because the two are directly related by a simple formula:
summer ice minimum = (previous) winter ice maximum - total spring/summer melt
...


Instead of answering the question as to the existence (or otherwise) of such a correlation, that was simply a descriptive statement of an obvious equality. A similar example of an obvious equality from the world of finance would be...

Closing share price = Opening share price + Change in share price

Although taken from entirely different spheres, these two equality statements share a common weakness: namely that, in the absence of any reliable form of time travel - other than the usual unidirectional 1 second per second familiar to everyone - the predictive skill of each is precisely zero.

As Steven goes on to stress, although there is a strongly positive correlation when the metric is volume, that breaks down when looking at either extent or area. In the summer of 2013, Rob Dekker and myself independently wrote articles on this subject for Neven's Arctic Sea Ice Blog.

http://neven1.typepad.com/blog/2013/06/problematic-predictions.html (http://neven1.typepad.com/blog/2013/06/problematic-predictions.html)
http://neven1.typepad.com/blog/2013/07/problematic-predictions-2.html (http://neven1.typepad.com/blog/2013/07/problematic-predictions-2.html)

Bringing that a bit more up to date, and using Excel's CORREL function on the NSIDC monthly values for both Artic Sea Ice extent and area for September 1979 - March 2017...

Correlation between September extent (year X) and March extent (year X+1) = 0.739
Correlation between September area (year X) and March area (year X+1) = 0.678

However, those seemingly meaningful correlations are largely due to the overall downward trend in the dataset(s).

March extent trend = - 42k sq kms/annum
March area trend = - 32k sq kms/annum

September extent trend = - 87k sq kms/annum
September area trend = - 79k sq kms/annum

Once the data has been de-trended (using a simple least-squares linear regression), the output(s) of the CORREL function change to...

Correlation between September extent (year X) and March extent (year X+1) = -0.068
Correlation between September area (year X) and March area (year X+1) = -0.165

As Steven stated, this represents a pretty weak level of correlation - and it actually comes out as being weakly negative.


N.B. As mentioned earlier, during those array comparisons, the average September value of (year X) would be paired with the average March value of (year X+1). The reason for this particular arrangement was because Gerontocrat's original question concerned the correlation if only the freezing season was considered. Had the question pertained to the melting season, then March and September values from the same year would have been compared.

However, it would not really have made much difference, as the de-trended correlations for the March - September melt season are also very weak...

extent = 0.000
area = -0.022
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on April 23, 2017, 08:21:22 PM
Update for the week to April 22nd

The current 5 day trailing average is on 13,587,000km2 while the 1 day extent is at 13,493,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -935,000km2, a decrease from -966,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -515,000km2, an increase from -445,000km2 last week. We're currently 2nd lowest on record, down from lowest last week.

(http://i.imgur.com/T7AfKY0.png)

The average daily change over the last 7 days was -32.9k/day, compared to the long term average of -37.3k/day, and the 07, 11 and 12 average of -22.8k/day.
The average long term change over the next week is -40.7k/day, with the 07, 11, and 12 average being -44.2k/day.

(http://i.imgur.com/HW2AEwP.png)

The extent loss so far this April is the 14th smallest record. To achieve the largest loss, a drop of at least 130.0k/day is required (more than -157.4k/day with with single day values), while the smallest drop requires a loss of less than 14.4k/day (less than 3.5k/day with single day values) and an average loss requires a drop of 65.7k/day (-71.9k/day with single day values).

(http://i.imgur.com/FOmhzK1.png)
Title: Re: 2017 sea ice area and extent data
Post by: gregcharles on April 27, 2017, 08:22:13 PM
Today is a five year anniversary of being below average. Based on the Charctic Interactive Sea Ice (http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/), it's now been five years since arctic sea ice extent was last above the 1981-2010 median.
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on May 01, 2017, 11:12:13 AM
Update for the week to April 29th

The current 5 day trailing average is on 13,587,000km2 while the 1 day extent is at 13,493,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -790,000km2, a decrease from -935,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -346,000km2, a decrease from -515,000km2 last week. We're currently 2nd lowest on record, the same as last week.

(http://i.imgur.com/1RTTgXC.png)

The average daily change over the last 7 days was -20.1k/day, compared to the long term average of -40.7k/day, and the 07, 11 and 12 average of -44.2k/day.
The average long term change over the next week is -43.1k/day, with the 07, 11, and 12 average being -45.2k/day.

(http://i.imgur.com/2VDcj4o.png)

The extent loss so far this April is the 4th smallest record. To achieve the largest loss, a drop of at least 898.5k/day is required (more than -4,457.1k/day with with single day values), while the smallest drop an increase of at least than 25.5k/day (at least 161.9k/day with single day values) and an average loss requires a drop of 385.2k/day (1,891.0k/day with single day values).

(http://i.imgur.com/iTIX40z.png)
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on May 07, 2017, 06:44:32 PM
Update for the week to May 6th

The current 5 day trailing average is on 13,070,000km2 while the 1 day extent is at 13,079,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -736,000km2, a decrease from -790,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -271,000km2, a decrease from -346,000km2 last week. We're currently 3rd lowest on record, down from 2nd lowest last week.

(http://i.imgur.com/iNxM0EC.png)

The average daily change over the last 7 days was -53.9k/day, compared to the long term average of -61.6k/day, and the 07, 11 and 12 average of -64.6k/day.
The average long term change over the next week is -43.3k/day, with the 07, 11, and 12 average being -38.4k/day.

(http://i.imgur.com/GgjT4uH.png)

The extent loss so far this May is the 14th smallest record. To achieve the largest loss, a drop of at least 70.9k/day is required (more than -77.3k/day with with single day values), while the smallest loss requires a drop of less than 18.8k/day (less than 20.8k/day with single day values) and an average loss requires a drop of 43.8k/day (48k/day with single day values).

(http://i.imgur.com/f30pQJf.png)

The extent loss in April was the 3rd smallest on record, while the average extent was the 2nd lowest on record.

(http://i.imgur.com/RBoJqZB.png)

(http://i.imgur.com/Udsa48k.png)
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on May 12, 2017, 03:56:31 PM
Time for an update concerning sea ice area calculated from NSIDC sea ice concentration compared with extent (same as calculated by NSIDC).

While extent is 5th lowest (~690k higher than 2016), area has dropped to #10, more than 1 Million higher than 2016.

Here are the rankings for 11th May:

extent NH
datum: -05-11
2005-05-11 13.119149
2003-05-11 13.056350
2011-05-11 12.968637
2007-05-11 12.940884
2014-05-11 12.876776
2017-05-11 12.830311
2015-05-11 12.757955
2004-05-11 12.709222
2006-05-11 12.709040
2016-05-11 12.143364

area NH
2017-05-11 11.467165
2007-05-11 11.449676
2003-05-11 11.447578
2004-05-11 11.381959
2014-05-11 11.324955
2010-05-11 11.241607
2011-05-11 11.145334
2015-05-11 11.144258
2006-05-11 11.007650
2016-05-11 10.454304
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on May 12, 2017, 04:06:40 PM
How is the situation wrt sea ice measured by NSIDC restricted to the Arctic Basin regions?

NSIDC extent has dropped from the 100% ice cover and is among the front runners (well behind 2016).

That can not be said of area, still in the middle of the pack and behind most of the recent (2006 and later) years.
Title: Re: 2017 sea ice area and extent data
Post by: Neven on May 12, 2017, 10:14:39 PM
Thanks, Wip, that's some great info (as always).
Title: Re: 2017 sea ice area and extent data
Post by: charles_oil on May 12, 2017, 11:20:51 PM

So is it that the outlying areas (which will melt out) are holding on, maybe due to the "wacky" weather whereas the key, core area is already declining ?

Title: Re: 2017 sea ice area and extent data
Post by: Jim Williams on May 13, 2017, 12:14:18 AM

So is it that the outlying areas (which will melt out) are holding on, maybe due to the "wacky" weather whereas the key, core area is already declining ?

Isn't that what I am seeing in the Nares?

Weather isn't that wacky...the cold that used to stay at the pole has to dissipate somewhere.
Title: Re: 2017 sea ice area and extent data
Post by: slow wing on May 13, 2017, 12:45:05 AM
Thanks Wipneus! I really like your plots restricted to the Arctic Basin regions.

Note the big offset scale - the fractional declines shown in those plots by 11 May are only a couple of percent at most.

2016 has the biggest declines by 11 May. (The purple line on Wipneus' plots.) The reason can be seen from the concentration maps for 13 May (but 11 May for 2017):

https://sites.google.com/site/arcticseaicegraphs/concentration-maps/sic0513 (https://sites.google.com/site/arcticseaicegraphs/concentration-maps/sic0513)

In all the other years, all of the Arctic Basin sea ice is nearly intact through 13 May. In 2016 though, it is seen that the Beaufort Sea had already opened up by a significant amount by 13 May, as shown by the red arrow:


Title: Re: 2017 sea ice area and extent data
Post by: jdallen on May 13, 2017, 06:54:41 AM
How is the situation wrt sea ice measured by NSIDC restricted to the Arctic Basin regions?

NSIDC extent has dropped from the 100% ice cover and is among the front runners (well behind 2016).

That can not be said of area, still in the middle of the pack and behind most of the recent (2006 and later) years.
For all of that, most of the difference in both extent and area is in three areas:  the Barents sea, Greenland Sea and Baffin Bay.

It will dissappear rapidly.
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on May 15, 2017, 01:44:01 PM
Update for the week to May 13th

The current 5 day trailing average is on 13,070,000km2 while the 1 day extent is at 13,079,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -672,000km2, a decrease from -736,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -241,000km2, a decrease from -271,000km2 last week. We're currently 5th lowest on record, down from 3rd lowest last week.


(http://i.imgur.com/jB5Z65b.png)

The average daily change over the last 7 days was -34.1k/day, compared to the long term average of -43.3k/day, and the 07, 11 and 12 average of -38.4k/day.
The average long term change over the next week is -44.2k/day, with the 07, 11, and 12 average being -47.1k/day.

(http://i.imgur.com/3QHTUP4.png)

The extent loss so far this May is the 12th smallest record. To achieve the largest loss, a drop of at least 85.2k/day is required (more than -86.6k/day with single day values), while the smallest loss requires a drop of less than 12.8k/day (less than 5.3k/day with single day values) and an average loss requires a drop of 47.5k/day (44.4k/day with single day values).

(http://i.imgur.com/JM7aU9k.png)
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on May 23, 2017, 03:09:24 PM
NSIDC extent is 5th lowest place (nearly equal to  2006 at #4).
Area (from NSIDC SIC) only at 9th position, now behind 2012 at #7.

extent NH
datum: -05-22
2007-05-22 12.565060
1995-05-22 12.558821
2014-05-22 12.523640
2010-05-22 12.454524
2011-05-22 12.390777
2017-05-22 12.376212
2006-05-22 12.370576
2004-05-22 12.291722
2015-05-22 12.213506
2016-05-22 11.591323
area NH
2007-05-22 10.731251
2017-05-22 10.723499
2005-05-22 10.699015
2012-05-22 10.679585
2008-05-22 10.666784
2015-05-22 10.520421
2006-05-22 10.410440
2011-05-22 10.399773
2010-05-22 10.388519
2016-05-22 9.860509
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on May 23, 2017, 03:15:08 PM
Restricting to the Arctic Basin regions 2017 extent is second behind 2016 relatively far from other years.
Area is less extreme, but still among the lowest recent years.
Title: Re: 2017 sea ice area and extent data
Post by: TerryM on May 23, 2017, 05:27:20 PM
This is unexpected - can't wait for PIOMAS.
Terry
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on May 23, 2017, 09:43:23 PM
Update for the week to May 20th

The current 5 day trailing average is on 12,543,000km2 while the 1 day extent is at 12,514,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -651,000km2, a decrease from -672,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -200,000km2, a decrease from -241,000km2 last week. We're currently 5th lowest on record, the same as last week.

(http://i.imgur.com/hHkgJri.png)

The average daily change over the last 7 days was -39.7k/day, compared to the long term average of -44.2k/day, and the 07, 11 and 12 average of -47.1k/day.
The average long term change over the next week is -50.0k/day, with the 07, 11, and 12 average being -54.1k/day.

(http://i.imgur.com/J7TpkeX.png)

The extent loss so far this May is the 8th smallest record. To achieve the largest loss, a drop of at least 113.2k/day is required (more than -134.9k/day with single day values), while the smallest loss requires an increase of at least 5.3k/day (at least 9.6k/day with single day values) and an average loss requires a drop of 51.5k/day (59.8k/day with single day values).

(http://i.imgur.com/7m4Mpbg.png)
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on May 29, 2017, 12:30:21 PM
Update for the week to May 28th

The current 5 day trailing average is on 12,278,000km2 while the 1 day extent is at 12,215,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -612,000km2, a decrease from -651,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -126,000km2, a decrease from -200,000km2 last week. We're currently 7th lowest on record, down from 5th lowest last week.

(http://i.imgur.com/uFnFHtO.png)

The average daily change over the last 7 days was -37.8k/day, compared to the long term average of -50.0k/day, and the 07, 11 and 12 average of -54.1k/day.
The average long term change over the next week is -51.4k/day, with the 07, 11, and 12 average being -52.5k/day.

(http://i.imgur.com/QiR0hSD.png)

The extent loss so far this May is the 7th smallest record. To achieve the largest loss, a drop of at least 244.6k/day is required (more than -457.5k/day with single day values), while the smallest loss requires an increase of at least 80.6k/day (at least 192.8k/day with single day values) and an average loss requires a drop of 75.6k/day (119.6k/day with single day values)

(http://i.imgur.com/yGAeHBg.png)
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on May 29, 2017, 03:06:45 PM
Area calculated from NSIDC concentration is currently dropping faster than extent. The latest figures (20170528) are now the fifth lowest (but only 68k below #2).
Extent is 6th lowest, 600k below #2.

extent NH
datum: -05-28
2008-05-28 12.316215
1995-05-28 12.298185
2014-05-28 12.222014
2004-05-28 12.208909
2017-05-28 12.155762
2010-05-28 12.114739
2011-05-28 12.104922
2006-05-28 11.999727
2015-05-28 11.840660
2016-05-28 11.265964

area NH
2014-05-28 10.417287
2005-05-28 10.415554
2008-05-28 10.403674
2015-05-28 10.244283
2010-05-28 10.102317
2017-05-28 10.072805
2012-05-28 10.060195
2006-05-28 10.052573
2011-05-28 10.005748
2016-05-28 9.506624

Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on May 29, 2017, 03:11:49 PM
Within the restricted Arctic Basin, extent is still second lowest. Area at #3 and dropping fast, a first sign of surface melting.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on May 29, 2017, 04:12:07 PM
Today's regional changes:
Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-05-28 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4456.6   +0.0    +5.4    913.7   +2.5   -17.8    722.9   +7.1    -0.5
               Kara Sea             Barents Sea           Greenland Sea
   872.5   -4.4   -17.7    454.2  -16.4  -182.4    653.9   -3.7   -24.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
  1018.5  -25.7   +22.9     48.7   -5.5   +12.8   1186.9   -3.2   -15.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   738.2   -0.0    -0.2    475.7   -2.5   -41.6    463.8   -3.1  -115.2
             Bering Sea          Sea of Okhotsk                   Lakes
    19.1   -1.7  -167.5     82.7   +0.1   -70.5    197.4   -7.7   +53.9
          Other regions       Total (ex. lakes)
    48.5   -1.9    -3.2  12155.8  -58.4  -615.0

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4264.2  -26.8   -21.0    808.2   -8.0   -59.5    615.0  -11.2   -39.0
               Kara Sea             Barents Sea           Greenland Sea
   692.8  -36.3   -69.7    281.0  -10.6  -132.2    480.1   -2.1   +25.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   677.0  -24.1   -37.1     14.5   -0.9    +3.4    827.4  -28.6  -137.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   609.0   +2.6   -71.6    363.9   -8.7   -95.6    382.7   -0.2  -132.4
             Bering Sea          Sea of Okhotsk                   Lakes
     8.5   -0.6   -64.2     33.0   +0.3   -38.8    120.3   +1.5   +38.2
          Other regions       Total (ex. lakes)
    15.5   -1.7    -4.3  10072.8 -157.0  -874.0


The attached delta images shows where concentration goes over/below 15% in dark blue/red; else concentration changes over 7% are colored light blue/red.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on May 30, 2017, 03:44:25 PM
Area (calculated from NSIDC sea ice concentration) continues to drop fast. Yesterday I reported a 5th place, today's numbers area the second lowest for the day. It will take a lot more melting to get to the first place.

Ranks:

extent NH
datum: -05-29
2007-05-29 12.295967
1995-05-29 12.295098
2004-05-29 12.228823
2014-05-29 12.194538
2017-05-29 12.106827
2010-05-29 12.052171
2011-05-29 12.044185
2006-05-29 12.012332
2015-05-29 11.792429
2016-05-29 11.209175

area NH
1995-05-29 10.404848
2014-05-29 10.360418
2007-05-29 10.358662
2015-05-29 10.189945
2006-05-29 10.097577
2010-05-29 10.056848
2011-05-29 10.033491
2012-05-29 9.998651
2017-05-29 9.952865
2016-05-29 9.416968
 
Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-05-29 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4456.6   +0.0    +4.6    913.7   +0.0   -18.0    722.3   -0.6    -0.5
               Kara Sea             Barents Sea           Greenland Sea
   864.3   -8.2   -26.0    445.4   -8.8  -182.8    653.0   -0.8   -23.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   997.6  -20.9   +11.5     22.5  -26.2   -13.9   1184.5   -2.4   -13.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   734.4   -3.8    -4.2    478.8   +3.1   -36.8    461.9   -1.9  -115.8
             Bering Sea          Sea of Okhotsk                   Lakes
    22.0   +2.9  -151.5     90.5   +7.9   -56.9    233.5  +35.6   +91.3
          Other regions       Total (ex. lakes)
    59.4  +10.9    +5.5  12106.8  -48.9  -620.9

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4245.7  -18.4   -31.6    811.7   +3.5   -55.9    608.6   -6.4   -41.3
               Kara Sea             Barents Sea           Greenland Sea
   647.3  -45.6  -112.7    250.0  -31.0  -156.2    479.5   -0.6   +28.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   661.4  -15.6   -44.0      8.2   -6.2    -3.1    815.3  -12.1  -147.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   618.8   +9.9   -60.1    363.8   -0.1   -93.0    377.9   -4.8  -136.2
             Bering Sea          Sea of Okhotsk                   Lakes
     9.2   +0.7   -58.0     35.0   +1.9   -33.6    126.8   +6.5   +45.8
          Other regions       Total (ex. lakes)
    20.5   +5.1    +0.0   9952.9 -119.8  -944.8


Title: Re: 2017 sea ice area and extent data
Post by: Neven on May 30, 2017, 05:35:23 PM
Hmmm, I think it's high time I retrieve some of your data, Wip, and look at compactness. What with SIA going low in the ranking, and SIE staying up (relatively speaking).
Title: Re: 2017 sea ice area and extent data
Post by: Neven on May 30, 2017, 10:46:40 PM
As there is no more CT SIA, I've downloaded NSIDC extent and area data from Wipneus's site (is nsidc_arc_nt_main.txt the right file for that?) and made the compactness graph below. 2017 is currently second lowest. The lower the percentage, the more dispersed the ice pack is (either because it really is dispersed, or because melt ponds create this impression).
Title: Re: 2017 sea ice area and extent data
Post by: Jim Williams on May 30, 2017, 10:48:37 PM
I'm beginning to think I want to know the total linear kilometers of cracks in the ice, and a comparison with previous years.  I think that would tell us a lot, but I haven't a clue how to go about it.

Even defining it could get hard.  Does one just measure the polynya, or do you measure the circumference of each block?
Title: Re: 2017 sea ice area and extent data
Post by: Reggie on May 30, 2017, 11:02:47 PM
As there is no more CT SIA, I've downloaded NSIDC extent and area data from Wipneus's site (is nsidc_arc_nt_main.txt the right file for that?) and made the compactness graph below. 2017 is currently second lowest. The lower the percentage, the more dispersed the ice pack is (either because it really is dispersed, or because melt ponds create this impression).

Would it be safe to conclude that there is minimal ponding at the present time and the low concentration is mostly due to dispersion?
Title: Re: 2017 sea ice area and extent data
Post by: Neven on May 30, 2017, 11:24:23 PM
Would it be safe to conclude that there is minimal ponding at the present time and the low concentration is mostly due to dispersion?

I'm not sure, but I don't think it's safe to conclude there is minimal ponding right now, as temps have been going up lately and skies are pretty clear over much of the Arctic.

At the same time things look pretty dispersed on the Atlantic side of the Arctic, especially in the vicinity of Novaya Zemlya:

(https://gibs.earthdata.nasa.gov/image-download?TIME=2017150&extent=573440.0000000007,-229376.0000000007,2160640.000000001,1208319.9999999993&epsg=3413&layers=MODIS_Terra_CorrectedReflectance_TrueColor,Coastlines&opacities=1,1&worldfile=false&format=image/jpeg&width=775&height=702)
Title: Re: 2017 sea ice area and extent data
Post by: StopTheApocalypse on May 30, 2017, 11:37:34 PM
Related question: is there some index that tracks the "cloudiness" if you will, of the arctic? As a new follower of sea ice, I'm trying to get a handle on what a typical season might look like.
Title: Re: 2017 sea ice area and extent data
Post by: oren on May 30, 2017, 11:52:11 PM
Would it be safe to conclude that there is minimal ponding at the present time and the low concentration is mostly due to dispersion?
Depends on the location. Take a look on Worldview at Hudson Bay, scroll back and forth over several weeks - the bluish color is now everywhere. Some other areas also became somewhat bluish recently.
Title: Re: 2017 sea ice area and extent data
Post by: magnamentis on May 31, 2017, 12:07:27 AM
Related question: is there some index that tracks the "cloudiness" if you will, of the arctic? As a new follower of sea ice, I'm trying to get a handle on what a typical season might look like.

i think that "typical" currently is and will be the last that applies. IMO it's even not recommended to rely on typical patterns when it comes to get the bigger picture, it nowadays often leads to false assumptions and the corresponding heated debates (at times LOL)
Title: Re: 2017 sea ice area and extent data
Post by: Reggie on May 31, 2017, 12:26:47 AM
@ Neven

 "I'm not sure, but I don't think it's safe to conclude there is minimal ponding right now, as temps have been going up lately and skies are pretty clear over much of the Arctic

At the same time things look pretty dispersed on the Atlantic side of the Arctic, especially in the vicinity of Novaya Zemlya:"

@ Oren
 "Depends on the location. Take a look on Worldview at Hudson Bay, scroll back and forth over several weeks - the bluish color is now everywhere. Some other areas also became somewhat bluish recently."

 I agree 100 percent.  My question regarding ponding was poorly phrased and should have excluded the last week or so. The effects of the recent "torching" on the North American side of the Arctic have become obvious on Worldview, particularly in Hudson Bay and Amundsen Gulf.
Title: Re: 2017 sea ice area and extent data
Post by: Richard Rathbone on June 01, 2017, 05:18:05 PM
The compactness drop in the NSIDC measure is somewhat larger than the AMSR2 ones. This is not unusual for the time of year and usually gets put down to NSIDC being more sensitive to melt pond appearance.
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on June 04, 2017, 05:00:55 PM
Update for the week to June 3rd

The current 5 day trailing average is on 11,858,000km2 while the 1 day extent is at 11,681,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -672,000km2, an increase from -612,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -179,000km2, an increase from -126,000km2 last week. We're currently 4th lowest on record, up from 7th lowest last week.

(http://i.imgur.com/BeQQoMX.png)

The average daily change over the last 7 days was -60.1k/day, compared to the long term average of -51.4k/day, and the 07, 11 and 12 average of -52.5k/day.
The average long term change over the next week is -52.4k/day, with the 07, 11, and 12 average being -75.5k/day.

(http://i.imgur.com/9dVFW8V.png)

The extent loss so far this June is the 7th largest on record. To achieve the largest loss, a drop of at least 98.7k/day is required (more than -99.5k/day with single day values), while the smallest loss requires a drop of less than 30.9k/day (less than 26.2k/day with single day values) and an average loss requires a drop of 53.3k/day (50.5k/day with single day values).

(http://i.imgur.com/KiKHMUn.png)

The extent loss in May was the 12th smallest on record while the average extent was the 5th smallest on record.

(http://i.imgur.com/RKYvoe4.png)
(http://i.imgur.com/27f2bWl.png)

Title: Re: 2017 sea ice area and extent data
Post by: Csnavywx on June 04, 2017, 07:08:34 PM
That looks familiar:
(http://[url=https://www.esrl.noaa.gov/psd/tmp/composites/compday.Id_1hMmi9w.gif]https://www.esrl.noaa.gov/psd/tmp/composites/compday.Id_1hMmi9w.gif[/url])

(http://www.tropicaltidbits.com/analysis/models/ecmwf/2017060400/ecmwf_z500a_nhem_6.png)
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on June 09, 2017, 04:44:43 PM
Both extent and area calculated from NSIDC sea ice concentration have been overtaken by 2012 now.  Extent is 6th lowest, area is at place 5.

extent NH
datum: -06-08
2009-06-08 11.676325
2008-06-08 11.631845
2005-06-08 11.529974
2006-06-08 11.450210
2017-06-08 11.388661
2012-06-08 11.376244
2011-06-08 11.333488
2015-06-08 11.312987
2010-06-08 11.254079
2016-06-08 10.870105

area NH
2014-06-08 9.578384
2008-06-08 9.537484
2015-06-08 9.483089
2006-06-08 9.478056
2011-06-08 9.469125
2017-06-08 9.278360
2007-06-08 9.276071
2010-06-08 9.203477
2012-06-08 9.082649
2016-06-08 8.675202

Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on June 09, 2017, 04:50:32 PM
In the restricted Arctic Basin, extent has now taken the first (lowest) place.
Area is still within a pack of several recent years. The melt pond induced cliff should come now fast to stay in competition.
Title: Re: 2017 sea ice area and extent data
Post by: seaicesailor on June 09, 2017, 05:27:38 PM
In other words
Title: Re: 2017 sea ice area and extent data
Post by: RoxTheGeologist on June 09, 2017, 05:53:33 PM

The low area and the sparse number of FDDs would suggest that the ice in the CAB is in very poor shape despite the lack of darkening. If there is a lot of snow on the ice would that keep the reflectivity of the surface up but not have a huge impact on the resilience to bottom melt?

If the snow is concealing thin ice it would also make a precipitous decline more likely once the snow melts.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on June 13, 2017, 06:43:04 PM
Double century drop in area calculated from NSIDC sea ice concentration. Surface melting seems to have begun.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-06-12 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4435.3   +0.7   -14.8    885.3   +3.8   -43.0    704.8   -4.5    -3.8
               Kara Sea             Barents Sea           Greenland Sea
   727.1  -52.8  -148.1    289.0  +11.6  -238.4    570.7   +0.8   -80.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   765.0  -24.5   -73.5      5.7   -4.2    -0.4   1065.7  +22.6   -42.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   741.9   -0.6   +18.6    429.0   -5.1   -67.4    357.8  -10.0  -173.0
             Bering Sea          Sea of Okhotsk                   Lakes
    21.5   +5.4   -38.1     57.9  -12.3   -29.2    159.8   -4.0   +28.8
          Other regions       Total (ex. lakes)
    12.5   +3.4    +9.5  11069.4  -65.7  -923.9

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4222.6  -39.0   -28.4    778.2   +4.3   -45.4    590.7  -22.5    +3.5
               Kara Sea             Barents Sea           Greenland Sea
   454.6  -84.7  -257.2    150.6   +9.8  -171.9    382.7   +2.8   -32.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   482.8  -39.0   -96.3      1.4   -0.9    -0.4    591.5  -12.1  -204.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   635.5   -2.9    +9.0    339.7   -8.3   -66.5    295.9   -7.8  -159.5
             Bering Sea          Sea of Okhotsk                   Lakes
     5.9   +0.8   -14.0     19.5   -4.6   -17.9     96.8   -3.7   +27.8
          Other regions       Total (ex. lakes)
     3.8   +0.2    +2.8   8955.3 -203.8 -1079.8


Title: Re: 2017 sea ice area and extent data
Post by: gregcharles on June 13, 2017, 10:59:09 PM
@Wipneus I'm sure you've answered this before, but what is the basis for the anomalies? Is it an average of the whole satellite record, just recent years, or some other subset?

Meanwhile, Charctic (http://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/), which I believe is the NSIDC 5-day rolling average extent, shows 2016 with a significant, but diminishing lead over 2011, 2012, 2015, and 2017, which are oddly knotted together in a near dead heat for second.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on June 14, 2017, 07:07:19 AM
@Wipneus I'm sure you've answered this before, but what is the basis for the anomalies? Is it an average of the whole satellite record, just recent years, or some other subset?


Like NSIDC, it is the 1981-2010 mean.
Title: Re: 2017 sea ice area and extent data
Post by: Richard Rathbone on June 14, 2017, 01:50:48 PM
@Wipneus I'm sure you've answered this before, but what is the basis for the anomalies? Is it an average of the whole satellite record, just recent years, or some other subset?


Like NSIDC, it is the 1981-2010 mean.
Is what used to be the CT area anomaly graph available anywhere? That's what I used to use for judging just how cliffy June is.

 
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on June 14, 2017, 07:15:26 PM
Update for the week to June 10th

The current 5 day trailing average is on 11,371,000km2 while the 1 day extent is at 11,234,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -792,000km2, an increase from -672,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -136,000km2, a decrease from -179,000km2 last week. We're currently 4th lowest on record, the same as last week.

(http://i.imgur.com/o8PDIY5.png)

The average daily change over the last 7 days was -69.5k/day, compared to the long term average of -52.4k/day, and the 07, 11 and 12 average of -75.5k/day.
The average long term change over the next week is -46.1k/day, with the 07, 11, and 12 average being -82.6k/day.

(http://i.imgur.com/scEXVgp.png)

The extent loss so far this June is the 7th largest on record. To achieve the largest loss, a drop of at least 109.0k/day is required (more than -113.4k/day with single day values), while the smallest loss requires a drop of less than 17.5k/day (less than 11.8k/day with single day values) and an average loss requires a drop of 47.6k/day (45.3k/day with single day values).

(http://i.imgur.com/n1adnAC.png)
Title: Re: 2017 sea ice area and extent data
Post by: magnamentis on June 14, 2017, 08:24:35 PM
@Wipneus I'm sure you've answered this before, but what is the basis for the anomalies? Is it an average of the whole satellite record, just recent years, or some other subset?


Like NSIDC, it is the 1981-2010 mean.
Is what used to be the CT area anomaly graph available anywhere? That's what I used to use for judging just how cliffy June is.

yes it is, at least if this is what you mean :-)

just scroll down a bit hope it's right

https://sites.google.com/view/pettitclimategraphs
Title: Re: 2017 sea ice area and extent data
Post by: Richard Rathbone on June 15, 2017, 01:12:26 PM
@Wipneus I'm sure you've answered this before, but what is the basis for the anomalies? Is it an average of the whole satellite record, just recent years, or some other subset?


Like NSIDC, it is the 1981-2010 mean.
Is what used to be the CT area anomaly graph available anywhere? That's what I used to use for judging just how cliffy June is.

yes it is, at least if this is what you mean :-)

just scroll down a bit hope it's right

https://sites.google.com/view/pettitclimategraphs

Those are all extent, not area.
Title: Re: 2017 sea ice area and extent data
Post by: magnamentis on June 15, 2017, 05:12:05 PM
@Wipneus I'm sure you've answered this before, but what is the basis for the anomalies? Is it an average of the whole satellite record, just recent years, or some other subset?


Like NSIDC, it is the 1981-2010 mean.
Is what used to be the CT area anomaly graph available anywhere? That's what I used to use for judging just how cliffy June is.

yes it is, at least if this is what you mean :-)

just scroll down a bit hope it's right

https://sites.google.com/view/pettitclimategraphs

Those are all extent, not area.

yep, i was fooled by the similarity and just assumed there would be one for area as well, next time i 1st look better before posting, sorry ;)
Title: Re: 2017 sea ice area and extent data
Post by: Steven on June 16, 2017, 07:53:03 PM
Is what used to be the CT area anomaly graph available anywhere? That's what I used to use for judging just how cliffy June is.


There has been no "June cliff" in June 2017 so far, probably due to a lack of melt ponds.  In the graph below I used Arctic sea ice area data from Wipneus' site (https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data)  (filename:  nsidc_arc_nt_main.txt), which he calculates from NSIDC gridded sea ice concentration data.  In the graph I used 5-day running means to smooth the data.


(http://i.imgur.com/oIKplqD.png)
Title: Re: 2017 sea ice area and extent data
Post by: magnamentis on June 16, 2017, 08:21:26 PM
Is what used to be the CT area anomaly graph available anywhere? That's what I used to use for judging just how cliffy June is.


There has been no "June cliff" in June 2017 so far, probably due to a lack of melt ponds.  In the graph below I used Arctic sea ice area data from Wipneus' site ([url]https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data[/url])  (filename:  nsidc_arc_nt_main.txt), which he calculates from NSIDC gridded sea ice concentration data.  In the graph I used 5-day running means to smooth the data.


([url]http://i.imgur.com/oIKplqD.png[/url])


this is misleading somehow, june is one of the biggest overal loosers due to steady instead of cliff-like losses in extent and most probably in volume as well. further as wip posted there are significant losses going on in area currently. further i sea only one real cliff that deserves the name in that graph and that is 2012 coming from relatively high.

i just try to understand the motives behind this kind of post. it's obvious that things are in bad shape and primed for the worse, including forecasted weather for the next few days.

if someone is reading that post he/she could get an entirely different picture about what's going on hence IMO, even, what i don't know, the data are correct thus far, they neither represent the current situation nor do they any good to make and keep people alert to the situation.

of course as usual i'm ready to listen and learn what i'm missing, just my 2 cents.
Title: Re: 2017 sea ice area and extent data
Post by: seaicesailor on June 16, 2017, 08:49:18 PM
Magnamentis there is no reason to distrust the motives behind what simply is a piece of information with no distortion of any kind in a nice plot (thank you Steven).
Now I am surprised that you have mentioned the bad shape of extent. Yes it is.
I partly agree, 2012 dwarves the other cliffs but I guess it is important as well where area ends in second mid of June, ☀️
Title: Re: 2017 sea ice area and extent data
Post by: magnamentis on June 16, 2017, 10:12:07 PM
Magnamentis there is no reason to distrust the motives behind what simply is a piece of information with no distortion of any kind in a nice plot (thank you Steven).
Now I am surprised that you have mentioned the bad shape of extent. Yes it is.
I partly agree, 2012 dwarves the other cliffs but I guess it is important as well where area ends in second mid of June, ☀️

yes there is no reason and i basically explicitly ASKED for something i overlooked which implies the possibility that i don't get a point. this is fair enough i think and more or less the opposite.

still ihave to consider things come across in that way, probably because of the term "misleading" while i said "THIS" is misleading "IN SOME WAY" and not the person is mislieading.

all good i think and i hope i could clear that out and to i i submit my thanks for making me aware of possible misunderstandings and giving me the opportunity to clarify :-)

BTW to avoid OT i had such a nice private message ready ;) "big smile"

cheers

EDIT: my apologies to steven, nothing personal for sure and no offence meant, mea culpa for any bad wording.
Title: Re: 2017 sea ice area and extent data
Post by: Neven on June 16, 2017, 11:34:53 PM
yes there is no reason and i basically explicitly ASKED for something i overlooked which implies the possibility that i don't get a point. this is fair enough i think and more or less the opposite.

What you're missing is simply melt ponds, or to be more precise, the lack thereof. If there had been a lot of melt ponds (like in 2007 and 2012), area would have fallen off a cliff. And that's because for area melt ponds counts as open water, which is why scientists came up with the 15% threshold (ie extent) to dampen the influence of melt ponds on the numbers.

SIA hasn't fallen off a cliff so far, because there are relatively few melt ponds. Useful information, just like sea ice extent is.
Title: Re: 2017 sea ice area and extent data
Post by: magnamentis on June 16, 2017, 11:38:45 PM
yes there is no reason and i basically explicitly ASKED for something i overlooked which implies the possibility that i don't get a point. this is fair enough i think and more or less the opposite.

What you're missing is simply melt ponds, or to be more precise, the lack thereof. If there had been a lot of melt ponds (like in 2007 and 2012), area would have fallen off a cliff. And that's because for area melt ponds counts as open water, which is why scientists came up with the 15% threshold (ie extent) to dampen the influence of melt ponds on the numbers.

SIA hasn't fallen off a cliff so far, because there are relatively few melt ponds. Useful information, just like sea ice extent is.

great, thanks, so melt ponds somehow simulate water which lowers area numbers, just didn't have that present (stupid i) should have know that by now ;)
Title: Re: 2017 sea ice area and extent data
Post by: Neven on June 16, 2017, 11:41:24 PM
great, thanks, so melt ponds somehow simulate water which lowers area numbers, just didn't have that present (stupid i) should have know that by now ;)

No problem. But keep it mind before calling data useless or misleading again. All data is useful, it's what we do with it that can sometimes be wrong.  :)
Title: Re: 2017 sea ice area and extent data
Post by: Tor Bejnar on June 17, 2017, 01:17:01 AM
...
so melt ponds somehow simulate water which lowers area numbers, just didn't have that present (stupid i) should have know that by now ;)
Melt ponds are water!  But because it is water on top of ice floes, it shouldn't count as being ocean water.  But the satellite sensors cannot distinguish between salty (sometimes diluted with fresh water) ocean water and fresh (or brackish) melt pond water.

Before melt-ponding starts in May (and after they freeze over in October), extent:area ratios put numbers to ice floe compression or dispersion.  With melt ponds present, interpreting the ratio is much more complex.  If we could get a numerical sense of the amount of melt ponding, that would be quite cool.  How about pixel counting of the pale blue ice that others report (in cloud-free sections of the Arctic)?  (I sometimes think I see the tint of blue in Worldview images, but mostly I don't get it - I presume it is due to some degree of color blindness on my part.)
Title: Re: 2017 sea ice area and extent data
Post by: oren on June 17, 2017, 08:50:27 AM
How about pixel counting of the pale blue ice that others report (in cloud-free sections of the Arctic)?  (I sometimes think I see the tint of blue in Worldview images, but mostly I don't get it - I presume it is due to some degree of color blindness on my part.)

Tor - first you need to see a good example, and then it becomes easier. Best to look at fast ice, or at zoomed-out images of large areas. Jump a few days at a time.
Here's something I made for you as an example, posted in the Nares thread to avoid going further OT.
http://forum.arctic-sea-ice.net/index.php/topic,176.msg117326.html#msg117326 (http://forum.arctic-sea-ice.net/index.php/topic,176.msg117326.html#msg117326)
Title: Re: 2017 sea ice area and extent data
Post by: gerontocrat on June 17, 2017, 12:24:54 PM
Some more boring numbers (derived from Jaxa). I look at previous years' melt from the latest daily extent to minimum and the average for the last 10 years. The increase in June melt over the last week or two has made a 2nd lowest minimum for 2017 seem much more possible per the table below.

 As At June 16     Melt required     As % of 2007/2016 average
 For 2016 Result     6,089,458    100.7%
 For 2012 Result     6,929,267    114.6%
 For 2007 Result     6,040,983    99.9%

However, there is little change in the large additional percentage melt required for a lower than 2012 minimum. There are now just 90 days melting season remaining of which one would expect only 80 to be significant.

Title: Re: 2017 sea ice area and extent data
Post by: Jim Hunt on June 17, 2017, 02:21:38 PM
(I sometimes think I see the tint of blue in Worldview images, but mostly I don't get it - I presume it is due to some degree of color blindness on my part.)

Have you tried using MODIS bands 7-2-1? See for example:

https://go.nasa.gov/2tyHgL7

then compare with June 10th.
Title: Re: 2017 sea ice area and extent data
Post by: Jim Pettit on June 17, 2017, 05:30:05 PM
Just for kicks (and because I'm at a temporary stopping place in my dev work), I went ahead and made an NSIDC extent graph somewhat based on Espen's longstanding daily IJIS graphic:

(http://iwantsomeproof.com/extimg/sie_nsidc_six_week_detail.png)

(Anyone interested can find it in the NSIDC section on my graphics page (http://sites.google.com/view/pettitclimategraphs).)

That graph shows just how low extent is at the moment, despite May's slow decrease. But this graph shows it even better, I think:

(http://iwantsomeproof.com/extimg/sie_nsidc_daily_for_selected_years.png)
Title: Re: 2017 sea ice area and extent data
Post by: Tor Bejnar on June 17, 2017, 05:51:52 PM
(I sometimes think I see the tint of blue in Worldview images, but mostly I don't get it ...)
Have you tried using MODIS bands 7-2-1? See for example: https://go.nasa.gov/2tyHgL7 then compare with June 10th.
'Never viewed selected MODIS bands on my own.  And yes! I definitely see the different blues!
Has anyone attempted to use this data to discern the melt-pond faction of [extent - area]?
Title: Re: 2017 sea ice area and extent data
Post by: magnamentis on June 17, 2017, 05:59:03 PM
great, thanks, so melt ponds somehow simulate water which lowers area numbers, just didn't have that present (stupid i) should have know that by now ;)

No problem. But keep it mind before calling data useless or misleading again. All data is useful, it's what we do with it that can sometimes be wrong.  :)

yeah, useless is a hard word you're right. sometimes i'm writing too much per day and just loose patience or get carried away. always try to do better but at times fail, sorry for that.

cheers and a nice weekend @all
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on June 17, 2017, 06:30:04 PM
Re: melt ponds and MODIS.

Just to make sure that everyone is aware that a method is described:

http://icdc.cen.uni-hamburg.de/fileadmin/user_upload/icdc_Dokumente/roeseletal_MeltPondsonArcticSeaIceDeterminedfromMODISSatelliteDatausinganArtificialNeuralNetwork_TC_6_2012.pdf (http://icdc.cen.uni-hamburg.de/fileadmin/user_upload/icdc_Dokumente/roeseletal_MeltPondsonArcticSeaIceDeterminedfromMODISSatelliteDatausinganArtificialNeuralNetwork_TC_6_2012.pdf)

You will find  how clouds are filtered, the MODIS spectral bands to use and the influence that melt ponds have on the spectral bands.

Caution: the calculation to compute melt pond fraction from color band intensities is done with a neural net. This is completely unneeded, the equations in the paper can be solved directly. That would make redoing this relatively simple, just need some time.
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on June 18, 2017, 06:26:58 PM
Update for the week to June 17th

The current 5 day trailing average is on 10,780,000km2 while the 1 day extent is at 10,605,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,061,000km2, an increase from -792,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -150,000km2, an increase from -136,000km2 last week. We're currently 4th lowest on record, the same as last week.

(http://i.imgur.com/q2pqbo6.png)

The average daily change over the last 7 days was -84.5k/day, compared to the long term average of -46.1k/day, and the 07, 11 and 12 average of -82.6k/day.
The average long term change over the next week is -59.1k/day, with the 07, 11, and 12 average being -78.1k/day.

(http://i.imgur.com/7k7Ks0r.png)

The extent loss so far this June is the 2nd largest on record. To achieve the largest loss, a drop of at least 122.1k/day is required (more than -128.3k/day with single day values), while the smallest loss requires an increase of at least 18.7k/day (at least 38.0k/day with single day values) and an average loss requires a drop of 27.8k/day (16.9k/day with single day values).

(http://i.imgur.com/50iYTsj.png)
Title: Re: 2017 sea ice area and extent data
Post by: gerontocrat on June 22, 2017, 02:12:08 PM
A few days of strongish melting makes quite a difference.

On June 1st 2017 JAXA sea ice extent was 733,000 km2 greater than 2016, and average daily melting (from April 1) was 22% less than 2016.
As at 21st June that difference is down to 157,000 km2 and the average daily melting rate (again from April 1 ) is now only 2% less than 2016.

If melting from now to minimum is at the average of the previous 10 years, the 2017 minimum would tie with 2016 as 2nd lowest at 4.02 million km2. This is a significant change from earlier this month when a 5% above average melt would have been required.
However, to be a new record low (i.e. less than 2102) still requires remaining melting to be 15% above the 10 year average.
This is summarised in the little table below:-

 As At June 21       Melt required     As % av      Resulting Minimum
 For 2016 Result     5,711,402    100.0%    4,017,264
 For 2012 Result     6,551,211    114.8%    3,177,455
 For 2007 Result     5,662,927      99.2%    4,065,739
 Average 7-16 melt     5,708,577                4,020,089

The data illustrates how extraordinary the 2012 melting season was. (A similar story can be told on Greenland's melting in 2012).

There are about 85 days of the melting season left, of which perhaps 75 are significant in an average year. Although the Arctic temperatures are not yet at maximum, peak insolation day was yesterday.
If all other things are equal, a 2nd lowest minimum despite not particularly favourable climatic conditions seems eminently possible. However, not all other things are or will be equal. When will the thickness of the ice in the CAB reduce to below the point of no return?


Title: Re: 2017 sea ice area and extent data
Post by: magnamentis on June 22, 2017, 07:04:32 PM
A few days of strongish melting makes quite a difference.

On June 1st 2017 JAXA sea ice extent was 733,000 km2 greater than 2016, and average daily melting (from April 1) was 22% less than 2016.
As at 21st June that difference is down to 157,000 km2 and the average daily melting rate (again from April 1 ) is now only 2% less than 2016.

If melting from now to minimum is at the average of the previous 10 years, the 2017 minimum would tie with 2016 as 2nd lowest at 4.02 million km2. This is a significant change from earlier this month when a 5% above average melt would have been required.
However, to be a new record low (i.e. less than 2102) still requires remaining melting to be 15% above the 10 year average.
This is summarised in the little table below:-

 As At June 21       Melt required     As % av      Resulting Minimum
 For 2016 Result     5,711,402    100.0%    4,017,264
 For 2012 Result     6,551,211    114.8%    3,177,455
 For 2007 Result     5,662,927      99.2%    4,065,739
 Average 7-16 melt     5,708,577                4,020,089

The data illustrates how extraordinary the 2012 melting season was. (A similar story can be told on Greenland's melting in 2012).

There are about 85 days of the melting season left, of which perhaps 75 are significant in an average year. Although the Arctic temperatures are not yet at maximum, peak insolation day was yesterday.
If all other things are equal, a 2nd lowest minimum despite not particularly favourable climatic conditions seems eminently possible. However, not all other things are or will be equal. When will the thickness of the ice in the CAB reduce to below the point of no return?

this only applies if you mean area or extent, in fact we need much less melting  to reach the same amount of ice in september because the amount of ice in cubic-kilometers is much lower than any other year before.

that means that much less energy = melt is needed to reach the "non-goal" so to say.

again, if you refer to area and in parts extent only, your calculation has a point, just that i think we should go slowly away from optical to physical values, extent is optical, it's not real, it just is an impression, while volume is the only value that provides amount of ice = energy needed to melt it.

at the end of the story, once all the ice is gone in a given year, that amount of energy needed to melt the ice is what counts, else it can't happen, while extent numbers can vary so much.

a) example 1 :  5 meters thick and 20% cover
b) example 2 :  2 meters thick and 20% cover
c) example 3 :  5 meters thick and 100% cover etc.

if one's gonna calculate the difference in ice mass between exmaples 1 and 3 and the energy equivalent needed to melt it, we find ourselves in two totally different worlds (scenarious)

this and nothing personal is why i over and over spoil the game of so many hinting at that.
our live energy for a change should be used the most efficient way, more i don't say, else
some will be jumping again LOL

cheers all and enjoy further
Title: Re: 2017 sea ice area and extent data
Post by: Jim Pettit on June 24, 2017, 01:48:08 PM
Because IJIS will be out of commission until at least Monday, I'll post these NSIDC SIE graphs here for those anyone experiencing the early stages of withdrawal:

(http://iwantsomeproof.com/extimg/sie_nsidc_six_week_detail.png)

(http://iwantsomeproof.com/extimg/sie_nsidc_daily_for_selected_years.png)


Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on June 25, 2017, 08:11:03 AM
Sea ice extent within the restricted Arctic Basin (you know which regions that are) stays record low in the NSIDC satellite era. Area not so much, it is "only" 5th lowest place or so.
Something more about that in the next post.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on June 25, 2017, 08:53:20 AM
Comparing with other sea ice concentration data, Jaxa (AMSR2 sensor, bootstrap method) and Uni Hamburg (AMSR2 sensor, ASI method) all three agree that in the Arctic Basin extent is at the lowest (for Jaxa and UH that means since 2012) for the day of year.
However with area Jaxa and UH see it very different than NSIDC. They place area at record low too, while NSIDC places it in the middle of the recent-year-pack.

That makes it a little puzzle: I have gotten accustomed to NSIDC area to lead the other two when  making the summer dive. The summer dive is driven in large part by surface melting for which the NSIDC method (the Nasa Team algorithm) is hyper sensitive. So why not this year?

The last piece of the puzzle is Jaxa's melt ratio (calculated from its thickness and melt ice concentration maps) that is definitely showing less relatively melting this year in agreement with NSIDC area (even if I have not calculated the proper Arctic Basin melt ratio yet).

(Uni Hamburg data is only available up to 18th June but it seems we can safely assume that more recent data would change the picture much).
Title: Re: 2017 sea ice area and extent data
Post by: epiphyte on June 25, 2017, 09:34:28 AM
Comparing with other sea ice concentration data, Jaxa (AMSR2 sensor, bootstrap method) and Uni Hamburg (AMSR2 sensor, ASI method) all three agree that in the Arctic Basin extent is at the lowest (for Jaxa and UH that means since 2012) for the day of year.
However with area Jaxa and UH see it very different than NSIDC. They place area at record low too, while NSIDC places it in the middle of the recent-year-pack.

That makes it a little puzzle: I have gotten accustomed to NSIDC area to lead the other two when  making the summer dive. The summer dive is driven in large part by surface melting for which the NSIDC method (the Nasa Team algorithm) is hyper sensitive. So why not this year?

The last piece of the puzzle is Jaxa's melt ratio (calculated from its thickness and melt ice concentration maps) that is definitely showing less relatively melting this year in agreement with NSIDC area (even if I have not calculated the proper Arctic Basin melt ratio yet).

(Uni Hamburg data is only available up to 18th June but it seems we can safely assume that more recent data would change the picture much).

If I had to sum up the 2016/2017 winter in a sentence it would be" "More snow on top of less ice."
This may show no sign of melt at all until a very short time before it's gone. So it doesn't surprise me that NSIDC is on the high side for area, any more than it's surprising that the May melt pond fraction was low in areas (e.g. Laptev) that are now rapidly disintegrating.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on June 25, 2017, 02:23:28 PM
Area is understanding the situation and responds with a near two and a half century drop.
Chukchi, Beaufort, CAB and the CAA contribute most to the drop in area.


Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-06-24 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4456.6   +1.3   +10.6    861.8  +15.2   -59.0    669.9  +17.4   -20.4
               Kara Sea             Barents Sea           Greenland Sea
   678.6   +2.0  -146.3    165.2  -15.9  -242.5    540.4   -6.3   -65.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   620.7  +11.3   -79.8     12.5   +0.5    +6.1    572.3  -77.3  -340.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   728.7   -1.9   +14.2    355.9   +2.0  -118.4    295.1  -17.0  -179.1
             Bering Sea          Sea of Okhotsk                   Lakes
    14.0   -3.7   -28.0     52.8  -17.0   -21.4    209.6  +28.1   +83.5
          Other regions       Total (ex. lakes)
     9.6   -0.4    +6.7  10034.1  -89.7 -1263.4

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4142.8  -97.9    -1.5    639.5   -0.7  -101.1    434.5   +9.4   -84.5
               Kara Sea             Barents Sea           Greenland Sea
   423.3  -16.0  -194.1     88.8   -1.7  -144.3    332.0   +0.9   -18.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   375.9  -20.5   -61.3      4.7   +2.4    +3.0    276.9  -19.6  -287.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   550.9  -34.7   +14.6    184.5  -30.6  -178.6    176.0  -31.7  -196.6
             Bering Sea          Sea of Okhotsk                   Lakes
     3.6   -0.0    -8.5     16.6   -6.2   -10.8    108.3   +4.5   +44.0
          Other regions       Total (ex. lakes)
     3.4   -0.6    +2.4   7653.4 -247.4 -1267.2


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on June 25, 2017, 04:07:24 PM
Update for the week to June 24th

The current 5 day trailing average is on 10,214,000km2 while the 1 day extent is at 10,034,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,213,000km2, an increase from -1,061,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -169,000km2, an increase from -150,000km2 last week. We're currently 4th lowest on record, the same as last week.

(http://i.imgur.com/YJ5uCuF.png)

The average daily change over the last 7 days was -80.9k/day, compared to the long term average of -59.1k/day, and the 07, 11 and 12 average of -78.1k/day.
The average long term change over the next week is -69.4k/day, with the 07, 11, and 12 average being -100.2k/day.

(http://i.imgur.com/FfS1cNA.png)

The extent loss so far this June is the 4th largest on record. To achieve the largest loss, a drop of at least 170.1k/day is required (more than -210.2k/day with single day values), while the smallest loss requires an increase of at least 134.8k/day (at least 247.1k/day with single day values) and an average loss requires an increase of 32.4k/day (96.2k/day with single day values).

(http://i.imgur.com/Tu3KZEp.png)
Title: Re: 2017 sea ice area and extent data
Post by: Tor Bejnar on June 25, 2017, 04:19:39 PM
The average long term change over the next week is -69.4k/day, with the 07, 11, and 12 average being -100.2k/day.
Wow, the average of three different (yes, big) years over this next week is a century per day!
Title: Re: 2017 sea ice area and extent data
Post by: Shared Humanity on June 25, 2017, 04:35:02 PM
The average long term change over the next week is -69.4k/day, with the 07, 11, and 12 average being -100.2k/day.
Wow, the average of three different (yes, big) years over this next week is a century per day!

Tough acts to follow.
Title: Re: 2017 sea ice area and extent data
Post by: Neven on June 25, 2017, 06:17:07 PM
NSIDC compactness dropping muy rapido:
Title: Re: 2017 sea ice area and extent data
Post by: seaicesailor on June 26, 2017, 12:16:31 PM
NSIDC compactness dropping muy rapido:
Late Dr. Slater forecast takes a similar plunge
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on June 26, 2017, 04:19:40 PM
Area, calculated from NSIDC sea ice concentration, keeps dropping fast, the epicenter now shifting to the CAA and the bordering CAB.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-06-25 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4454.6   -2.0    +9.6    854.2   -7.6   -65.1    670.0   +0.1   -23.1
               Kara Sea             Barents Sea           Greenland Sea
   649.0  -29.5  -172.4    158.7   -6.5  -241.0    535.7   -4.7   -61.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   602.1  -18.7   -86.2     14.1   +1.6    +8.5    549.3  -23.0  -348.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   726.2   -2.5   +13.5    347.0   -8.8  -126.4    294.0   -1.1  -174.2
             Bering Sea          Sea of Okhotsk                   Lakes
    15.7   +1.7   -26.9     58.5   +5.6   -14.5    215.8   +5.3   +90.4
          Other regions       Total (ex. lakes)
    11.8   +2.3    +8.6   9940.8  -93.2 -1300.2

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4063.4  -79.4   -60.7    643.5   +4.0   -99.1    438.1   +3.6   -78.3
               Kara Sea             Barents Sea           Greenland Sea
   392.3  -31.0  -212.5     88.7   -0.1  -135.5    318.4  -13.6   -25.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   377.1   +1.2   -47.9      3.9   -0.9    +2.3    266.1  -10.8  -282.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   501.4  -49.6   -26.2    177.4   -7.2  -183.7    181.5   +5.5  -185.6
             Bering Sea          Sea of Okhotsk                   Lakes
     3.3   -0.3    -8.7     15.2   -1.3   -11.7    107.9   -0.7   +44.5
          Other regions       Total (ex. lakes)
     3.8   +0.4    +2.7   7474.2 -179.2 -1352.3


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%

 
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on June 27, 2017, 05:01:01 PM
Slow day according to the NSIDC sea ice concentration, area even had a small uptick. Most of that happened in the CAB where previous days losses rebound now.


Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-06-26 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4455.3   +0.6   +10.6    844.5   -9.7   -75.1    651.9  -18.0   -36.1
               Kara Sea             Barents Sea           Greenland Sea
   658.7   +9.6  -159.0    169.0  +10.3  -221.3    558.1  +22.5   -33.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   580.7  -21.3   -97.9     10.9   -3.1    +5.3    545.6   -3.7  -331.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   728.7   +2.5   +18.7    347.8   +0.7  -122.0    284.2   -9.8  -180.5
             Bering Sea          Sea of Okhotsk                   Lakes
    14.0   -1.7   -28.3     51.1   -7.4   -21.6    233.3  +16.6  +106.6
          Other regions       Total (ex. lakes)
    12.5   +0.7    +9.0   9913.0  -27.8 -1263.3

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4140.0  +76.6   +28.4    609.7  -33.8  -130.8    416.5  -21.6   -94.6
               Kara Sea             Barents Sea           Greenland Sea
   407.8  +15.4  -186.1     91.4   +2.7  -125.5    314.4   -4.0   -22.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   366.6  -10.5   -43.6      2.7   -1.1    +1.1    261.0   -5.1  -265.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   467.9  -33.4   -51.6    204.8  +27.4  -151.2    189.1   +7.7  -174.8
             Bering Sea          Sea of Okhotsk                   Lakes
     3.0   -0.4    -8.7     17.0   +1.7    -9.9    115.0   +7.0   +51.2
          Other regions       Total (ex. lakes)
     4.1   +0.3    +2.9   7496.1  +21.9 -1232.6


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on June 28, 2017, 03:02:26 PM
Extent resumes the fast drop, area stays behind.


Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-06-27 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4455.3   +0.0   +11.2    841.3   -3.2   -77.9    669.9  +18.0   -17.9
               Kara Sea             Barents Sea           Greenland Sea
   629.2  -29.4  -183.4    160.5   -8.6  -222.6    553.7   -4.4   -29.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   522.2  -58.6  -144.5      3.6   -7.3    -2.5    515.4  -30.1  -339.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   711.8  -16.9    +2.3    347.2   -0.6  -122.2    269.2  -15.0  -190.9
             Bering Sea          Sea of Okhotsk                   Lakes
    17.0   +3.0   -23.6     55.1   +4.0   -17.3    221.4  -12.9   +93.5
          Other regions       Total (ex. lakes)
    12.5   -0.0    +9.3   9764.0 -149.1 -1348.8

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4153.8  +13.7   +56.9    597.9  -11.9  -136.9    411.6   -4.8   -95.4
               Kara Sea             Barents Sea           Greenland Sea
   396.6  -11.2  -188.6     87.2   -4.3  -124.2    307.1   -7.3   -21.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   326.7  -40.0   -73.3      1.1   -1.6    -0.6    237.5  -23.5  -268.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   473.2   +5.3   -40.3    225.2  +20.4  -126.1    195.6   +6.5  -160.8
             Bering Sea          Sea of Okhotsk                   Lakes
     4.3   +1.3    -6.6     15.7   -1.2   -10.7    106.7   -8.6   +43.3
          Other regions       Total (ex. lakes)
     3.9   -0.3    +2.8   7437.2  -58.9 -1193.6


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on June 29, 2017, 03:35:47 PM
Century extent drop, most in the Hudson region, but only a small change in area.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-06-28 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4455.3   +0.0   +11.4    833.2   -8.1   -84.9    657.0  -12.9   -28.4
               Kara Sea             Barents Sea           Greenland Sea
   617.8  -11.4  -188.6    166.7   +6.3  -204.9    551.8   -1.9   -25.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   507.6  -14.5  -144.9      9.9   +6.2    +3.2    465.1  -50.3  -361.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   701.2  -10.6    -5.7    342.1   -5.1  -124.0    262.3   -6.9  -192.0
             Bering Sea          Sea of Okhotsk                   Lakes
    19.9   +2.9   -20.0     47.3   -7.8   -23.9    183.5  -37.9   +53.5
          Other regions       Total (ex. lakes)
     7.8   -4.7    +4.6   9645.0 -119.0 -1385.5

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4176.5  +22.7  +115.6    591.5   -6.3  -140.3    426.1  +14.5   -75.5
               Kara Sea             Barents Sea           Greenland Sea
   382.9  -13.7  -191.0     79.6   -7.6  -126.3    305.8   -1.3   -16.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   320.7   -5.9   -69.9      2.0   +0.9    +0.0    221.0  -16.5  -265.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   472.9   -0.2   -32.5    225.8   +0.6  -118.7    194.7   -0.9  -151.4
             Bering Sea          Sea of Okhotsk                   Lakes
     4.7   +0.4    -6.1     13.8   -1.9   -12.2    102.5   -4.1   +38.4
          Other regions       Total (ex. lakes)
     3.0   -0.9    +2.0   7421.1  -16.1 -1088.2


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on June 29, 2017, 03:43:54 PM
Update of the Basin only graphics based on the NSIDC sea ice concentration. Extent is still the lowest ever (in the satellite era) but area is back in the common peloton. As before, Jaxa and Uni Hamburg see this different (not shown) where area 2017 is still a leader.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on June 30, 2017, 03:17:03 PM
From NSIDC sea concentration I calculate another century drop in extent, a bit less in area.


Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-06-29 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4455.9   +0.7   +12.9    826.8   -6.3   -91.6    657.1   +0.1   -25.2
               Kara Sea             Barents Sea           Greenland Sea
   601.5  -16.4  -199.3    153.0  -13.8  -210.2    545.6   -6.3   -29.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   482.9  -24.7  -155.9      7.3   -2.6    +1.1    435.1  -30.0  -368.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   707.3   +6.1    +2.4    326.9  -15.2  -136.3    259.1   -3.2  -189.7
             Bering Sea          Sea of Okhotsk                   Lakes
    11.1   -8.8   -27.9     55.5   +8.2   -14.0    151.2  -32.3   +21.1
          Other regions       Total (ex. lakes)
     6.1   -1.6    +3.0   9531.2 -113.8 -1428.2

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4166.7   -9.8  +140.5    582.6   -8.9  -146.8    445.2  +19.1   -47.4
               Kara Sea             Barents Sea           Greenland Sea
   374.5   -8.4  -188.7     69.3  -10.4  -130.1    299.6   -6.2   -17.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   297.4  -23.3   -79.7      1.4   -0.5    -0.2    206.2  -14.8  -258.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   483.9  +10.9   -14.0    211.7  -14.2  -126.0    178.0  -16.7  -160.8
             Bering Sea          Sea of Okhotsk                   Lakes
     3.4   -1.4    -6.8     14.0   +0.2   -11.1     92.9   -9.6   +28.3
          Other regions       Total (ex. lakes)
     2.5   -0.4    +1.6   7336.3  -84.8 -1044.6


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: Shared Humanity on June 30, 2017, 05:42:47 PM
Hudson and Baffin continue to be 50% of SIE loss.
Title: Re: 2017 sea ice area and extent data
Post by: jplotinus on June 30, 2017, 06:17:45 PM
A chunk of ice off northeast tip of Severny Island has gone missing today, perhaps because of strong northwest wind, as reported for Dikson. So Baffin and Hudson may have some company in tomorrow's report.
Title: Re: 2017 sea ice area and extent data
Post by: Shared Humanity on June 30, 2017, 07:22:56 PM
And the rest of that ice looks like hell.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 01, 2017, 01:54:35 PM
In comes another century extent loss, this time area loss is even bigger.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-06-30 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4455.9   +0.0   +15.2    820.4   -6.4   -97.0    629.4  -27.6   -53.6
               Kara Sea             Barents Sea           Greenland Sea
   610.5   +9.0  -182.8    133.6  -19.4  -189.4    544.8   -0.7   -13.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   488.2   +5.3  -134.7     16.1   +8.9   +14.8    387.2  -48.0  -393.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   701.7   -5.6    +0.6    318.8   -8.1  -141.5    251.7   -7.5  -191.9
             Bering Sea          Sea of Okhotsk                   Lakes
    13.4   +2.3    +8.0     43.5  -11.9   +38.0    149.4   -1.8   +13.0
          Other regions       Total (ex. lakes)
     5.6   -0.5    +5.3   9420.9 -110.3 -1316.3

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4105.2  -61.4  +125.3    562.6  -20.0  -155.8    441.0   -4.2   -53.9
               Kara Sea             Barents Sea           Greenland Sea
   372.3   -2.2  -181.5     70.7   +1.4  -112.0    305.5   +5.9    -0.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   290.4   -7.0   -75.3      3.7   +2.3    +3.2    177.3  -28.9  -268.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   474.0   -9.9   -24.9    203.5   -8.2  -133.4    165.6  -12.4  -163.4
             Bering Sea          Sea of Okhotsk                   Lakes
     3.6   +0.2    +2.1     12.1   -2.0   +10.8     89.3   -3.6   +23.6
          Other regions       Total (ex. lakes)
     2.4   -0.2    +2.3   7189.9 -146.5 -1025.2


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: Shared Humanity on July 01, 2017, 07:48:33 PM
The dramatic drop in area in the CAB must be a sign of extensive melt ponds forming.
Title: Re: 2017 sea ice area and extent data
Post by: Pi26 on July 01, 2017, 08:10:24 PM
In comes another century extent loss, this time area loss is even
....
Area (value, one day change, anomaly):
East Siberian Sea
562.6  -20.0  -155.8   

ESS SIA - seems a fast growing dangerous burner gets tanked up as never before.
Anomaly could reach -200K km2 within a week?
Title: Re: 2017 sea ice area and extent data
Post by: cesium62 on July 01, 2017, 10:57:39 PM
This one is for NSIDC sea ice extent monthly/September average minimum

What is an "average minimum"?  For each day in september you go plus and minus 15 days to get a monthly average and then take the minimum of those 30 samples?

These are the September minimums for the last 12 years ...

    2012: 3.63


You used "September average" on the poll title, then said it was the "September average minimum", then gave data for the "September minimum"...  I'm a computer programmer and a math major, can we be more literal and consistent? ;D

Charctic says that the NSIDC 2012 September daily minimum was 3.387, so presumably we are consistently not talking about that.
Title: Re: 2017 sea ice area and extent data
Post by: Neven on July 01, 2017, 11:19:17 PM
What is an "average minimum"? 

You're right, that's not very clear. I'll change that.

All I try to do, is explain that there are two polls, one for the September average (that month being the month of the minimum, when the Arctic sea ice pack is smallest) and one for the daily minimum. This is confusing to a lot of people, just like the difference between area and extent is.

The September average is best-known because the NSIDC has used it consistently for many years now (it's also used for the SIPN sea ice outlook). But people enjoy watching the changes on a daily basis and prefer not to wait until the first week of October to find out what the September minimum was. Hence the popularity of JAXA, formerly known as IJIS.

That's why we have a poll for both measures.
Title: Re: 2017 sea ice area and extent data
Post by: Pi26 on July 01, 2017, 11:37:26 PM
This one is for NSIDC sea ice extent monthly/September average minimum

What is an "average minimum"?  For each day in september you go plus and minus 15 days to get a monthly average and then take the minimum of those 30 samples?

These are the September minimums for the last 12 years ...

    2012: 3.63


You used "September average" on the poll title, then said it was the "September average minimum", then gave data for the "September minimum"...  I'm a computer programmer and a math major, can we be more literal and consistent? ;D

Charctic says that the NSIDC 2012 September daily minimum was 3.387, so presumably we are consistently not talking about that.

I could not find that comment of Neven within this thread, even if he answered you here COMPLETLY OFFTOPIC ;)
But then I found (probably inspired by Adam Riese) you tried to post into another thread?:o ::

Arctic sea ice / NSIDC 2017 Arctic SIE September average: July poll

Title: Re: 2017 sea ice area and extent data
Post by: Jim Williams on July 02, 2017, 12:38:04 AM
What is an "average minimum"? 

You're right, that's not very clear. I'll change that.

All I try to do, is explain that there are two polls, one for the September average (that month being the month of the minimum, when the Arctic sea ice pack is smallest) and one for the daily minimum. This is confusing to a lot of people, just like the difference between area and extent is.

The September average is best-known because the NSIDC has used it consistently for many years now (it's also used for the SIPN sea ice outlook). But people enjoy watching the changes on a daily basis and prefer not to wait until the first week of October to find out what the September minimum was. Hence the popularity of JAXA, formerly known as IJIS.

That's why we have a poll for both measures.

What about if the minimum average and/or minimum is in October, not September?
Title: Re: 2017 sea ice area and extent data
Post by: cesium62 on July 02, 2017, 06:43:46 AM
I could not find that comment of Neven within this thread, even if he answered you here COMPLETLY OFFTOPIC ;)

[The message I was quoting referenced this thread, and seemed to strongly caution against going off-topic in the polling thread.  Arguably, I was discussing the definition of the data and not the poll.  In any event, yes, I'm not so good at figuring out the precise boundaries of each topic.]
Title: Re: 2017 sea ice area and extent data
Post by: Neven on July 02, 2017, 09:20:35 AM
What about if the minimum average and/or minimum is in October, not September?

I'll change the text again when that happens.

But yes, the poll thread would be the right place to discuss nomenclature and definitions, as this thread is about sea ice area and extent data.
Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on July 02, 2017, 02:27:47 PM
Update for the week to July 1st

The current 5 day trailing average is on 9,521,000km2 while the 1 day extent is at 9,244,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,420,000km2, an increase from -1,213,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -160,000km2, a decrease from -169,000km2 last week. We're currently 4th lowest on record, the same as last week.

(http://i.imgur.com/Iy9I0ak.png)

The average daily change over the last 7 days was -98.9k/day, compared to the long term average of -69.4k/day, and the 07, 11 and 12 average of -100.2k/day.
The average long term change over the next week is -88.4k/day, with the 07, 11, and 12 average being -131.5k/day.

(http://i.imgur.com/Dqnpjx7.png)

The extent loss so far this July is the 4th largest on record. To achieve the largest loss, a drop of at least 113.6k/day is required (more than -111.8k/day with single day values), while the smallest loss requires a drop of less than 63.3k/day (less than 58.0k/day with single day values) and an average loss a drop of 85.2k/day (81.4k/day with single day values).

(http://i.imgur.com/Vnl6nvF.png)

The extent loss in June was the 4th largest on record while the average extent was the 5th smallest on record.

(http://i.imgur.com/ELydFbR.png)

(http://i.imgur.com/9xAs3Mr.png)
Title: Re: 2017 sea ice area and extent data
Post by: seaicesailor on July 02, 2017, 03:13:57 PM
9,244k is almost a double century...
Title: Re: 2017 sea ice area and extent data
Post by: Steven on July 02, 2017, 05:02:17 PM
Now that June is over, here's a graph of sea ice area anomaly.  I used the sea ice area numbers that Wipneus reports daily in this thread (which he calculates from NSIDC sea ice concentration data)  with values for previous years here (https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_arc_nt_main.txt).  I smoothed the data by using 5-day running averages.  Sea ice area is currently 6th lowest for the date.  The June 2017 monthly average was also 6th lowest.

(http://i.imgur.com/ePRamk3.png)
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 02, 2017, 06:09:56 PM
First of the month effect makes the drops extra large, by perhaps -30k extent and -10k area. Still big number though.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-01 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4456.6   +0.7   +14.3    809.1  -11.3  -106.4    615.9  -13.6   -63.9
               Kara Sea             Barents Sea           Greenland Sea
   602.6   -7.8  -184.4    125.8   -7.8  -191.6    548.4   +3.5    -9.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   459.6  -28.6  -149.7      7.8   -8.4    +7.6    348.1  -39.1  -416.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   696.2   -5.6    -6.3    303.0  -15.8  -151.5    246.5   -5.2  -192.1
             Bering Sea          Sea of Okhotsk                   Lakes
     5.4   -8.0    +0.7     16.5  -27.0   +14.7    138.7  -11.1    +2.8
          Other regions       Total (ex. lakes)
     2.9   -2.7    +2.9   9244.3 -176.6 -1432.2

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4059.7  -45.6   +98.6    541.1  -21.6  -167.6    426.2  -14.9   -66.3
               Kara Sea             Barents Sea           Greenland Sea
   352.2  -20.0  -192.9     66.6   -4.1  -109.7    310.5   +5.1    +7.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   272.3  -18.2   -82.4      2.0   -1.7    +1.9    166.3  -10.9  -259.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   480.8   +6.8   -22.5    188.2  -15.3  -143.3    168.0   +2.4  -155.2
             Bering Sea          Sea of Okhotsk                   Lakes
     2.3   -1.2    +1.1      3.7   -8.4    +3.1     80.4   -8.8   +14.7
          Other regions       Total (ex. lakes)
     2.1   -0.3    +2.1   7042.0 -147.8 -1085.0


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: Jim Williams on July 02, 2017, 06:16:37 PM
What about if the minimum average and/or minimum is in October, not September?

I'll change the text again when that happens.

But yes, the poll thread would be the right place to discuss nomenclature and definitions, as this thread is about sea ice area and extent data.

Fine, but I will be watching the area and extent on December 31, since I think whenever the end comes the time of year isn't going to matter.
Title: Re: 2017 sea ice area and extent data
Post by: Tor Bejnar on July 02, 2017, 08:58:30 PM
BFTV's graph (duplicated here) suggests this first week of July is frequently the fastest melt week of the season.
(http://i.imgur.com/Dqnpjx7.png)
Title: Re: 2017 sea ice area and extent data
Post by: Archimid on July 03, 2017, 03:01:00 AM
Saw this at Reddit, I thought you might appreciate it. It is a novel visualization of Global, Arctic and Antarctic sea ice area from 1978 til present.

http://i.imgur.com/jZJz6Tq.gifv (http://i.imgur.com/jZJz6Tq.gifv)
Title: Re: 2017 sea ice area and extent data
Post by: magnamentis on July 03, 2017, 02:26:22 PM
Saw this at Reddit, I thought you might appreciate it. It is a novel visualization of Global, Arctic and Antarctic sea ice area from 1978 til present.

[url]http://i.imgur.com/jZJz6Tq.gifv[/url] ([url]http://i.imgur.com/jZJz6Tq.gifv[/url])


great find, thanks a lot, tells it all which is why weekly and regional details are irrelevant. it's permanently getting closer to the center with seasonal and yearly variations of course. nothing else matters.

EDIT: hope thanking people is welcome here, despite "ad nauseam" LOL
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 03, 2017, 03:00:47 PM
Extent did not manage another century, more than compensated by the drop in area: large concentration losses in the CAB and ESS.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-02 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4455.3   -1.3   +12.6    775.0  -34.1  -138.1    627.4  +11.5   -48.3
               Kara Sea             Barents Sea           Greenland Sea
   593.0   -9.6  -191.2    127.1   +1.3  -181.6    518.7  -29.7   -36.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   455.0   -4.6  -142.3      8.3   +0.5    +8.3    342.3   -5.8  -402.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   691.1   -5.0   -10.6    289.8  -13.2  -159.8    244.1   -2.4  -187.9
             Bering Sea          Sea of Okhotsk                   Lakes
     7.8   +2.4    +3.0     15.8   -0.7   +15.8    156.2  +16.0   +20.2
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   9153.6  -90.7 -1455.9

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4005.0  -54.6   +64.5    487.0  -54.0  -215.0    429.5   +3.3   -57.2
               Kara Sea             Barents Sea           Greenland Sea
   343.1   -9.1  -192.3     66.3   -0.3  -102.0    292.0  -18.5    -4.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   264.9   -7.4   -80.6      2.3   +0.3    +2.3    159.1   -7.2  -250.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   466.8  -14.0   -40.7    170.9  -17.2  -153.2    169.3   +1.2  -147.6
             Bering Sea          Sea of Okhotsk                   Lakes
     2.7   +0.4    +1.5      3.7   -0.0    +3.6     88.9   +8.1   +22.7
          Other regions       Total (ex. lakes)
     2.2   +0.1    +2.2   6864.7 -177.3 -1169.6


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: gerontocrat on July 04, 2017, 02:14:14 PM
Once again, I throw in some numbers. Jaxa data as at July 3.

The first little table is a projection of what has to happen for various results. Despite the increase in daily melt recently, nothing really changes. A second lowest minimum looks eminently possible, a record low increasingly unlikely.
The magic 1 million km2 would require remaining melt to be 66% greater than the 2007-16 average remaining melt, over 3 times the variation from the average in the Great Leap Forward of 2012 (19%).

The second table just looks at melt to date and remaining melt over the years. On average, 53% of melting happened by July 3. 2012 looks like an outlier for the melt achieved in the remainder of the season.

Unless the condition of the ice this year is fundamentally, dramatically, different then it still looks like a case of the slow-motion train wreck continuing.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 04, 2017, 03:12:51 PM
Moderate extent drop, but area declined strongly. CAB area scored a single region century, indicating widespread surface melting.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-03 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4454.6   -0.6   +12.3    786.6  +11.6  -125.5    617.8   -9.6   -58.1
               Kara Sea             Barents Sea           Greenland Sea
   595.6   +2.5  -183.0    130.3   +3.2  -171.9    505.6  -13.0   -40.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   453.6   -1.5  -133.3      5.7   -2.6    +5.7    315.6  -26.7  -408.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   676.8  -14.3   -26.5    275.9  -13.9  -168.3    241.0   -3.0  -183.2
             Bering Sea          Sea of Okhotsk                   Lakes
     6.6   -1.2    +1.9     18.2   +2.4   +18.2    169.1  +12.9   +32.5
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   9086.7  -66.8 -1458.1

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3892.8 -112.2   -37.2    477.0  -10.0  -216.0    436.7   +7.2   -44.5
               Kara Sea             Barents Sea           Greenland Sea
   339.2   -4.0  -188.2     68.3   +2.0   -94.2    288.3   -3.7    -0.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   267.4   +2.5   -70.3      1.5   -0.8    +1.5    147.2  -11.9  -246.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   444.2  -22.6   -66.3    170.9   -0.1  -149.1    160.2   -9.1  -146.8
             Bering Sea          Sea of Okhotsk                   Lakes
     2.6   -0.1    +1.4      4.6   +0.9    +4.6     89.1   +0.3   +23.2
          Other regions       Total (ex. lakes)
     2.2   +0.0    +2.2   6703.0 -161.8 -1249.4


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: Shared Humanity on July 04, 2017, 03:19:25 PM


Unless the condition of the ice this year is fundamentally, dramatically, different then it still looks like a case of the slow-motion train wreck continuing.

Given the impossibly warm winter, the resulting anomalously low volume and the increasingly fractured and mobile nature of the sea ice, I believe that is exactly what we have.

That being said, I agree that a 2nd place finish in extent is most likely.
Title: Re: 2017 sea ice area and extent data
Post by: magnamentis on July 04, 2017, 05:25:21 PM
Given the impossibly warm winter, the resulting anomalously low volume and the increasingly fractured and mobile nature of the sea ice, I believe that is exactly what we have.

That being said, I agree that a 2nd place finish in extent is most likely.

well possible but most likely implies that chances for a new low would be close to none and that i would not sign. nevertheless, nobody can predict that (wheather ? ) so i agree to a 50% chance for second place but not to the close to exclusion of a new low.
Title: Re: 2017 sea ice area and extent data
Post by: Jim Williams on July 04, 2017, 07:45:14 PM
<snip, off-topic, and yet again, I would like to urge others as well to stay on-topic, be short if possible, and do not be lazy when quoting others, but cut out everything except the thing you're responding to; N.>
Title: Re: 2017 sea ice area and extent data
Post by: Neven on July 04, 2017, 10:44:55 PM
Moderate extent drop, but area declined strongly. CAB area scored a single region century, indicating widespread surface melting.

And so the 2017 trend line on the compactness graph drops to the middle of the pack (again):
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 05, 2017, 06:55:48 PM
Another century extent drop, near century in area. Hudson still accounts for nearly half of the total drop in extent.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-04 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4454.0   -0.6   +12.8    772.6  -14.0  -136.2    617.8   -0.0   -56.9
               Kara Sea             Barents Sea           Greenland Sea
   592.3   -3.2  -180.2    115.4  -14.9  -180.5    497.5   -8.1   -41.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   424.1  -29.4  -154.3      8.3   +2.6    +8.3    266.7  -48.9  -437.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   669.0   -7.9   -34.6    281.6   +5.7  -159.1    240.2   -0.8  -179.1
             Bering Sea          Sea of Okhotsk                   Lakes
     9.0   +2.4    +4.5     11.4   -6.8   +11.4    199.6  +29.0   +60.7
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   8962.8 -124.0 -1520.2

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3838.4  -54.4   -76.0    473.6   -3.4  -210.8    449.3  +12.6   -29.9
               Kara Sea             Barents Sea           Greenland Sea
   335.7   -3.5  -184.0     57.1  -11.2  -101.0    281.3   -7.0    -1.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   253.7  -13.7   -75.1      1.9   +0.4    +1.9    134.0  -13.2  -242.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   451.0   +6.8   -63.4    171.3   +0.4  -147.6    154.9   -5.2  -142.9
             Bering Sea          Sea of Okhotsk                   Lakes
     2.2   -0.4    +1.0      2.8   -1.7    +2.8     99.0   +9.6   +32.4
          Other regions       Total (ex. lakes)
     2.1   -0.1    +2.1   6609.4  -93.6 -1266.7


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: gerontocrat on July 06, 2017, 02:56:51 PM
Contrasting Data (JAXA).
Extent is still reducing somewhat below 2007-2016 average. (by about 240,000 km2 to July 5).
Record low looking less likely day by day if previous years are any guide. See Table below.

But Jaxa AMSR2 volume graph shows very impressive volume reduction since mid-June.
Title: Re: 2017 sea ice area and extent data
Post by: oren on July 06, 2017, 03:07:27 PM
The 1 million goal is "impossible" but the 2012 goal not so. 2012 had a freak August extent loss, on ~average volume loss, as posted in one of threads recently. The reason, besides good regional distribution, was the ice was thin coming out of June/July, and a good blow wiped a lot of it. So it could be claimed that the real freak was the early volume loss, and that the later loss was somewhat predictable.
When I'm back at a computer next weekend I will try to dig up some numbers to see if this can be substantiated.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 06, 2017, 06:45:27 PM
Also NSIDC sea ice concentration makes drops in area and extent smaller than the past few days.


Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-05 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4446.9   -7.1    +6.6    765.0   -7.5  -142.3    616.4   -1.3   -54.5
               Kara Sea             Barents Sea           Greenland Sea
   587.7   -4.7  -172.7    103.7  -11.7  -184.9    519.8  +22.3   -10.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   409.6  -14.5  -154.6      4.6   -3.7    +4.6    257.2   -9.4  -423.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   665.0   -3.9   -34.5    275.9   -5.7  -160.5    229.0  -11.2  -183.9
             Bering Sea          Sea of Okhotsk                   Lakes
    14.4   +5.4    +9.5     11.6   +0.2   +11.6    169.1  -30.0   +30.0
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   8909.9  -52.8 -1486.0

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3899.4  +61.0    -4.6    470.9   -2.7  -208.0    429.7  -19.6   -49.5
               Kara Sea             Barents Sea           Greenland Sea
   330.5   -5.2  -177.1     49.3   -7.8  -105.1    287.1   +5.8   +11.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   246.4   -7.2   -67.9      1.2   -0.8    +1.2    122.8  -11.2  -236.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   446.1   -4.9   -64.9    162.5   -8.8  -150.1    135.6  -19.4  -156.7
             Bering Sea          Sea of Okhotsk                   Lakes
     3.7   +1.5    +2.4      2.8   -0.0    +2.8     92.4   -6.5   +27.5
          Other regions       Total (ex. lakes)
     2.2   +0.1    +2.2   6590.2  -19.1 -1200.4


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: magnamentis on July 06, 2017, 07:49:21 PM
now that hudson is almost void of ice, at least larger areas of it, we probably have to wait for other regions to gain a similar momentum which of course will happen but still the lack of ice to melt there would explain at least parts of today's slowdown.

still the drop was not out of the ordinary small in extent and area fluctuates heavily anyways, a bit of sweet water overfreezing in a cloudy and/or cool area and already it looks different for some time and will resume like before within some time to come.
Title: Re: 2017 sea ice area and extent data
Post by: gerontocrat on July 07, 2017, 02:01:58 PM
The 1 million goal is "impossible" but the 2012 goal not so. 2012 had a freak August extent loss, on ~average volume loss, as posted in one of threads recently. The reason, besides good regional distribution, was the ice was thin coming out of June/July, and a good blow wiped a lot of it. So it could be claimed that the real freak was the early volume loss, and that the later loss was somewhat predictable.
When I'm back at a computer next weekend I will try to dig up some numbers to see if this can be substantiated.
Hullo Oren,
I hope you can do the number business. I guess one day I will have to expand my data collection from just Jaxa Extent to include some volume data, as it is the volume loss to extent loss inconsistency that has to break sometime. Meanwhile some more JAXA numbers before I go to sleep over the weekend.

After the less than average 66,000 drop in extent on July 6, total melt this year of 5.37 million km2 is now 270,000 km2 (4.8%) less than the 2007-16 average. The table below shows that melt has to increase that bit more for even a second lowest minimum. Each day gone is nearly 1.5% of the remaining melt season gone. I have also posted again the chart of daily melt average over the last 10 years, 2012, and 2017 to date, mostly to show the weirdness of 2012.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 07, 2017, 06:24:59 PM
Area went fast downward again today, not far from a double century. Much of it within the Basin.

The extent drops are in comparison moderate.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-06 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4455.3   +8.4   +15.2    747.9  -17.2  -157.9    610.6   -5.8   -56.7
               Kara Sea             Barents Sea           Greenland Sea
   590.3   +2.6  -161.7    103.7   -0.0  -177.0    499.2  -20.6   -21.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   401.6   -8.0  -147.3      5.7   +1.1    +5.7    282.4  +25.2  -365.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   646.9  -18.1   -51.2    259.5  -16.4  -174.7    213.0  -16.0  -195.1
             Bering Sea          Sea of Okhotsk                   Lakes
    14.5   +0.0    +9.0     12.0   +0.4   +12.0    151.4  -17.8   +14.2
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   8845.5  -64.5 -1463.8

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3840.8  -58.5   -46.3    437.7  -33.2  -238.0    406.0  -23.7   -67.7
               Kara Sea             Barents Sea           Greenland Sea
   308.9  -21.6  -189.5     54.1   +4.8   -94.5    268.4  -18.7    +3.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   229.9  -16.6   -73.8      1.4   +0.2    +1.4    124.2   +1.4  -216.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   455.0   +8.9   -55.3    149.7  -12.9  -157.7    122.7  -12.9  -165.8
             Bering Sea          Sea of Okhotsk                   Lakes
     4.0   +0.4    +2.6      3.1   +0.3    +3.1     89.0   -3.7   +24.8
          Other regions       Total (ex. lakes)
     2.2   +0.0    +2.2   6408.0 -182.2 -1292.8


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: greatdying2 on July 07, 2017, 08:43:18 PM
The extent drops are in comparison moderate.

Extent drops where it counts were strong: ESS, Chukchi, Beaufort. The +25 in Hudson is here today, gone tomorrow -- just a blip.

The CAA seems to have a region that the algorithm has trouble with, that today is a big red dot accounting for much of the -18 drop in that region, but looking back at recent photos alternates between big extent increases and decreases. In reality, that spot is largely melted out and going fast, but not that fast. (The attached image from Worldview yesterday -- today it is cloudy there). Does anyone know why the prediction algorithm has such trouble here?
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 08, 2017, 06:17:23 PM
GD2: yes Hudson cleared today, and the CAA somewhere between fully frozen and mostly melted is difficult for the rather low resolution NSIDC data. Note that area is much less affected, but has its own peculiarities.

Meanwhile fat centuries for the day.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-07 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4450.1   -5.1    +9.3    743.6   -4.2  -160.3    597.1  -13.6   -68.3
               Kara Sea             Barents Sea           Greenland Sea
   569.2  -21.1  -168.5    105.6   +2.0  -167.2    490.9   -8.3   -26.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   394.2   -7.4  -138.9      5.7   +0.0    +5.7    248.2  -34.3  -374.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   614.7  -32.2   -82.8    250.7   -8.9  -180.9    225.7  +12.8  -177.5
             Bering Sea          Sea of Okhotsk                   Lakes
     6.0   -8.4    +1.4     17.6   +5.6   +17.6    158.5   +7.1   +23.3
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   8722.3 -123.1 -1508.7

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3782.9  -57.9   -85.2    422.0  -15.7  -246.6    403.8   -2.2   -59.9
               Kara Sea             Barents Sea           Greenland Sea
   297.5  -11.4  -185.3     53.1   -0.9   -89.5    253.4  -15.1    -8.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   223.2   -6.7   -69.2      1.6   +0.2    +1.6    115.9   -8.3  -202.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   422.9  -32.1   -84.9    132.0  -17.6  -172.8    113.0   -9.7  -171.6
             Bering Sea          Sea of Okhotsk                   Lakes
     2.3   -1.8    +1.1      3.7   +0.6    +3.7     91.7   +2.8   +29.4
          Other regions       Total (ex. lakes)
     2.2   +0.0    +2.2   6229.4 -178.6 -1367.4


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: seaicesailor on July 08, 2017, 06:58:01 PM
All this with a 982 hPa in the middle of it all... impressive.
Compactness definitely down, leaving 2013/2014 league, next days most interesting
Title: Re: 2017 sea ice area and extent data
Post by: Shared Humanity on July 08, 2017, 08:41:13 PM
The Pacific side of the CAB looks weak all the way to the pole. The Atlantic side looks relatively strong due to the migration of the thicker ice. What are the chances we'll see an alarming end state for this melt season with the Pacific side of the CAB nearly ice free?
Title: Re: 2017 sea ice area and extent data
Post by: Neven on July 08, 2017, 11:36:59 PM
All this with a 982 hPa in the middle of it all... impressive.
Compactness definitely down, leaving 2013/2014 league, next days most interesting

Indeed, keeping apace with 2015 and 2016 now:
Title: Re: 2017 sea ice area and extent data
Post by: gerontocrat on July 09, 2017, 03:30:31 PM
JAXA AMSR2 volume below 6,000 km3.
Jaxa sea ice thickness graph shows ice in terrible state except for Atlantic border region.

BUT:-
JAXA sea ice extent losses in July so far well below average. If 2017 follows the last 10 year average (which of course it won't) 58% of the melt has already happened.

The chances of a record minimum have reduced (see table below).

Title: Re: 2017 sea ice area and extent data
Post by: BornFromTheVoid on July 09, 2017, 05:06:19 PM
Update for the week to July 7th

The current 5 day trailing average is on 8,824,000km2 while the 1 day extent is at 8,681,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,498,000km2, an increase from -1,420,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at +63,000km2, a decrease from -169,000km2 last week. We're currently 5th lowest on record, down from 4th lowest last week.

(http://i.imgur.com/iZ7dayR.png)

The average daily change over the last 7 days was -99.5k/day, compared to the long term average of -88.4k/day, and the 07, 11 and 12 average of -131.5k/day.
The average long term change over the next week is -81.5k/day, with the 07, 11, and 12 average being -111.6k/day.

(http://i.imgur.com/UcjL5m7.png)

The extent loss so far this July is the 10th largest on record. To achieve the largest loss, a drop of at least 117.9k/day is required (more than -122.3k/day with single day values), while the smallest loss requires a drop of less than 52.3k/day (less than 50.5k/day with single day values) and an average loss requires a drop of 80.8k/day (81.7k/day with single day values).

(http://i.imgur.com/hCvfMzR.png)
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 09, 2017, 06:24:49 PM
An extent drop of "only" 42k brings 2017 in third lowest position after 2011 and 2012. The -71k drop in area is almost entirely caused by the CAB.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-08 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4455.3   +5.1   +15.4    730.9  -12.7  -167.9    600.9   +3.9   -61.6
               Kara Sea             Barents Sea           Greenland Sea
   542.9  -26.3  -183.3    100.1   -5.6  -164.2    484.3   -6.6   -30.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   376.9  -17.3  -147.6      4.7   -1.0    +4.7    268.1  +19.9  -333.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   621.7   +7.0   -75.1    252.6   +1.9  -177.6    214.4  -11.3  -184.9
             Bering Sea          Sea of Okhotsk                   Lakes
     9.0   +2.9    +4.2     16.0   -1.7   +16.0    200.9  +42.5   +68.6
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   8680.7  -41.6 -1482.7

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3721.1  -61.9  -122.7    419.5   -2.5  -241.9    432.3  +28.4   -29.1
               Kara Sea             Barents Sea           Greenland Sea
   286.2  -11.3  -178.0     47.2   -5.9   -89.7    247.6   -5.8   -11.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   221.7   -1.5   -62.1      1.3   -0.3    +1.3    114.3   -1.7  -189.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   408.4  -14.5   -95.0    130.5   -1.5  -175.3    120.3   +7.3  -158.5
             Bering Sea          Sea of Okhotsk                   Lakes
     1.9   -0.3    +0.7      3.6   -0.1    +3.6    103.2  +11.6   +41.8
          Other regions       Total (ex. lakes)
     2.2   +0.0    +2.2   6158.0  -71.4 -1345.9


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 09, 2017, 06:33:20 PM
Update of the basin-only extent and area graphs. Today's  the string of daily lowest extent for 2017 ended.  The extent drop rate will really have to increase to stay with the lowest years. Area seems to be able to do that.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 10, 2017, 03:40:04 PM
Small extent drop and a big increase in area makes it feel like the end of August.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-09 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4455.9   +0.7   +15.7    723.4   -7.6  -172.4    604.2   +3.2   -53.5
               Kara Sea             Barents Sea           Greenland Sea
   527.0  -15.8  -189.5    102.7   +2.6  -152.3    476.3   -7.9   -31.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   403.3  +26.4  -108.4      6.8   +2.1    +6.8    235.5  -32.6  -346.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   612.3   -9.4   -83.1    273.5  +20.9  -154.3    210.0   -4.4  -185.2
             Bering Sea          Sea of Okhotsk                   Lakes
     7.2   -1.8    +2.2     16.4   +0.4   +16.4    158.8  -42.1   +24.3
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   8657.4  -23.2 -1432.7

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3810.1  +89.0   -13.2    407.3  -12.2  -248.9    434.0   +1.8   -22.4
               Kara Sea             Barents Sea           Greenland Sea
   266.7  -19.5  -186.4     49.6   +2.3   -81.6    246.6   -1.0    -7.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   233.0  +11.3   -39.8      1.8   +0.5    +1.8    100.5  -13.8  -188.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   398.8   -9.5  -105.5    164.3  +33.8  -140.8    117.2   -3.1  -156.0
             Bering Sea          Sea of Okhotsk                   Lakes
     1.6   -0.3    +0.4      3.8   +0.2    +3.8     90.8  -12.3   +29.0
          Other regions       Total (ex. lakes)
     2.2   -0.1    +2.2   6237.5  +79.4 -1182.4


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 11, 2017, 06:43:36 PM
Smallish extent drop and an area increase again.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-10 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4454.6   -1.3   +15.6    720.7   -2.6  -171.5    579.7  -24.5   -71.6
               Kara Sea             Barents Sea           Greenland Sea
   510.2  -16.9  -192.9     92.6  -10.1  -154.4    462.7  -13.6   -37.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   394.6   -8.7  -106.5     11.4   +4.7   +11.4    227.0   -8.5  -330.0
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   643.0  +30.7   -47.9    263.5  -10.1  -161.4    213.8   +3.7  -178.3
             Bering Sea          Sea of Okhotsk                   Lakes
     4.8   -2.4    +0.2     10.4   -6.0   +10.4    156.2   -2.7   +23.6
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   8591.9  -65.6 -1411.0

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3907.1  +97.0  +102.0    412.6   +5.4  -233.4    394.3  -39.8   -51.8
               Kara Sea             Barents Sea           Greenland Sea
   254.7  -11.9  -187.1     47.1   -2.4   -77.9    231.2  -15.4   -17.7
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   215.3  -17.8   -48.5      2.9   +1.1    +2.9     97.8   -2.7  -175.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   426.2  +27.4   -76.4    165.1   +0.8  -136.3    116.8   -0.4  -150.8
             Bering Sea          Sea of Okhotsk                   Lakes
     1.2   -0.5    -0.1      2.4   -1.4    +2.4     86.2   -4.6   +25.5
          Other regions       Total (ex. lakes)
     2.0   -0.1    +2.0   6276.7  +39.2 -1046.4


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: oren on July 11, 2017, 06:49:27 PM
The CAA suddenly filled up with blue pixels.
Title: Re: 2017 sea ice area and extent data
Post by: jplotinus on July 11, 2017, 08:02:00 PM
ESS near Wrangle and Pevek has not changed much in either extent or area from July 1 to 11, though warm(ish) temps >10°C are forecast all this week at Pevek.
Title: Re: 2017 sea ice area and extent data
Post by: Csnavywx on July 11, 2017, 09:48:56 PM
Should start crashing tomorrow or the 12th. Heavy Laptev loss was the first signal.
Title: Re: 2017 sea ice area and extent data
Post by: Tigertown on July 12, 2017, 12:25:06 AM
ESS near Wrangle and Pevek has not changed much in either extent or area from July 1 to 11, though warm(ish) temps >10°C are forecast all this week at Pevek.

 Recommend checking today's Homebrew thread. The data there paints a different picture for the 10th than the NSIDC does.
Area drop exceeds that of extent, much of it in the Chukchi/ESS regions.

Update 20170710.

Extent: -88.6
Area: -146.8


http://forum.arctic-sea-ice.net/index.php/topic,382.msg120316.html#msg120316
 
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 12, 2017, 02:29:55 PM
Yes, like the "homebrew" AMSR2  data, NSIDC shows a lot of extent and/or area losses all along the Eurasian coastal regions, especially Laptev.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-11 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4449.4   -5.2   +10.6    699.9  -20.8  -188.5    508.9  -70.8  -137.7
               Kara Sea             Barents Sea           Greenland Sea
   472.6  -37.6  -222.9     89.4   -3.2  -149.7    461.1   -1.6   -27.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   381.0  -13.6  -105.4      8.3   -3.1    +8.3    223.9   -3.1  -309.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   638.6   -4.4   -51.9    264.7   +1.3  -155.9    210.0   -3.7  -174.7
             Bering Sea          Sea of Okhotsk                   Lakes
     4.8   +0.0    +0.0     18.7   +8.8   +18.7    120.0  -36.2   -11.2
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   8434.4 -156.9 -1483.5

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3928.0  +20.9  +141.4    407.2   -5.4  -229.5    336.9  -57.4  -101.9
               Kara Sea             Barents Sea           Greenland Sea
   219.9  -34.9  -211.1     44.3   -2.9   -73.9    226.2   -5.0   -16.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   214.6   -0.7   -36.0      2.0   -0.9    +2.0     96.6   -1.2  -159.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   440.9  +14.7   -59.2    175.6  +10.5  -120.3    121.6   +4.8  -137.8
             Bering Sea          Sea of Okhotsk                   Lakes
     1.1   -0.1    -0.1      6.0   +3.7    +6.0     73.8  -12.2   +14.2
          Other regions       Total (ex. lakes)
     2.0   +0.0    +2.0   6223.0  -53.6  -994.9


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 13, 2017, 05:48:56 PM
Remarkable regional century for the ESS.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-12 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4443.5   -5.9    +5.5    582.3 -117.6  -301.9    524.2  +15.2  -118.8
               Kara Sea             Barents Sea           Greenland Sea
   469.5   -3.1  -213.5     94.6   +5.2  -140.3    442.5  -18.6   -36.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   387.5   +6.5   -85.9      9.4   +1.0    +9.4    206.3  -17.6  -301.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   630.9   -7.7   -56.9    271.1   +6.3  -148.2    193.1  -17.0  -187.8
             Bering Sea          Sea of Okhotsk                   Lakes
     1.8   -3.0    -3.2     14.2   -4.5   +14.2    148.2  +27.3   +15.4
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   8273.7 -160.7 -1562.5

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3918.9   -9.1  +154.9    353.5  -53.7  -280.8    338.4   +1.5   -93.6
               Kara Sea             Barents Sea           Greenland Sea
   224.8   +4.9  -196.5     46.3   +2.0   -67.8    211.0  -15.2   -28.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   211.6   -3.0   -27.8      2.6   +0.5    +2.6     89.8   -6.8  -149.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   441.1   +0.2   -55.2    178.1   +2.5  -112.4    111.3  -10.3  -142.5
             Bering Sea          Sea of Okhotsk                   Lakes
     0.3   -0.8    -0.9      3.6   -2.5    +3.6    102.3  +28.1   +41.9
          Other regions       Total (ex. lakes)
     2.1   +0.1    +2.1   6133.3  -89.6  -992.3


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: Shared Humanity on July 13, 2017, 06:13:38 PM
Wow! Looks like the Laptev is set to join the party.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 14, 2017, 06:06:17 PM
(near) double centuries for extent and area,  ESS scores a regional century (again). Laptev declines the invitation.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-13 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4443.5   +0.0    +5.6    446.7 -135.5  -431.2    560.4  +36.2   -74.1
               Kara Sea             Barents Sea           Greenland Sea
   451.5  -18.0  -217.2     81.5  -13.0  -146.2    446.6   +4.1   -26.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   358.4  -29.1  -100.9      9.4   -0.0    +9.4    190.8  -15.5  -291.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   629.6   -1.3   -58.5    279.9   +8.8  -135.0    149.5  -43.6  -226.0
             Bering Sea          Sea of Okhotsk                   Lakes
     9.6   +7.8    +4.9     14.8   +0.6   +14.8    137.9  -10.3    +2.8
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   8075.2 -198.5 -1669.3

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3863.3  -55.6  +109.4    281.3  -72.2  -344.9    351.1  +12.8   -71.0
               Kara Sea             Barents Sea           Greenland Sea
   208.7  -16.0  -202.4     47.6   +1.3   -62.3    208.4   -2.6   -25.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   193.2  -18.4   -37.3      2.4   -0.2    +2.4     80.5   -9.3  -142.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   424.4  -16.7   -71.7    177.7   -0.4  -107.5     86.4  -24.8  -160.9
             Bering Sea          Sea of Okhotsk                   Lakes
     1.8   +1.5    +0.6      3.9   +0.3    +3.9     84.8  -17.3   +24.2
          Other regions       Total (ex. lakes)
     2.2   +0.1    +2.2   5933.1 -200.3 -1108.1


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: Csnavywx on July 14, 2017, 06:16:55 PM
Boom. Subtropical air and ice don't mix.

Edit: It might have overdone the extent drop in the ESS and near Wrangel. There's still some >15% ice there on EOSDIS near Wrangel.
Title: Re: 2017 sea ice area and extent data
Post by: Tigertown on July 14, 2017, 06:31:33 PM
Boom. Subtropical air and ice don't mix.

Edit: It might have overdone the extent drop in the ESS and near Wrangel. There's still some >15% ice there on EOSDIS near Wrangel.
Yeah, but what time was the last satellite pass. It's pretty warm there now. Maybe going away by the hour at this point.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 14, 2017, 07:01:30 PM
Basin-only update. The extent decline accelerated and is now back to the lowest position (shared with 2011). Area is not particularly low among recent years.
Title: Re: 2017 sea ice area and extent data
Post by: greatdying2 on July 14, 2017, 08:03:11 PM
Wow  :-\

There goes the Chukchi too.
Title: Re: 2017 sea ice area and extent data
Post by: Shared Humanity on July 14, 2017, 09:06:19 PM
Laptev declines the invitation.


 ;)
Title: Re: 2017 sea ice area and extent data
Post by: Tor Bejnar on July 14, 2017, 09:23:04 PM
Wow, indeed.
Chukchi and ESS both lost roughly a quarter of the remaining ice (extent) in one 'day'.  You cannot keep that sort of rate (km2/day) up for too long. :o
Title: Re: 2017 sea ice area and extent data
Post by: greatdying2 on July 14, 2017, 09:58:08 PM
Wow, indeed.
Chukchi and ESS both lost roughly a quarter of the remaining ice (extent) in one 'day'.  You cannot keep that sort of rate (km2/day) up for too long. :o
I guess the CAB will also have to start dropping (plummeting??) soon...
Title: Re: 2017 sea ice area and extent data
Post by: RoxTheGeologist on July 14, 2017, 10:35:11 PM
Wow, indeed.
Chukchi and ESS both lost roughly a quarter of the remaining ice (extent) in one 'day'.  You cannot keep that sort of rate (km2/day) up for too long. :o

They border the CAB. The melt may continue at this rate past the arbitrary boundaries that we have imposed.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 15, 2017, 03:42:03 PM
Big drops in extent and area again. The drops in Kara are biggest where the ice caught  by Novaya Zemlya is disappearing. ESS rebounded somewhat, not unexpected after two consecutive days with a century.


Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-14 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4439.6   -3.9    +2.3    478.6  +31.9  -396.2    559.7   -0.6   -69.4
               Kara Sea             Barents Sea           Greenland Sea
   385.5  -66.0  -265.9     87.2   +5.6  -135.3    440.8   -5.9   -24.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   341.9  -16.6  -106.6      3.1   -6.3    +3.1    197.7   +6.9  -266.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   597.2  -32.4   -87.3    243.9  -36.0  -165.6    129.7  -19.7  -242.4
             Bering Sea          Sea of Okhotsk                   Lakes
     8.4   -1.2    +3.3     14.3   -0.5   +14.3    171.0  +32.6   +40.3
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   7930.4 -144.8 -1733.8

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3841.1  -22.2   +88.9    282.0   +0.8  -336.9    345.2   -6.0   -67.6
               Kara Sea             Barents Sea           Greenland Sea
   184.0  -24.8  -219.0     34.8  -12.7   -71.0    197.1  -11.3   -31.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   175.6  -17.6   -45.4      0.9   -1.5    +0.9     82.9   +2.3  -130.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   402.8  -21.6   -89.5    150.3  -27.5  -129.5     70.7  -15.7  -170.2
             Bering Sea          Sea of Okhotsk                   Lakes
     1.6   -0.2    +0.3      3.5   -0.4    +3.5     90.6   +5.7   +32.1
          Other regions       Total (ex. lakes)
     2.3   +0.1    +2.3   5774.8 -158.3 -1194.9


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 16, 2017, 06:54:39 PM
Very mixed picture. Large extent drops in Kara but rebounds in ESS and Chukchi. While UH AMSR2 "saw" concentration drops on the pacific side, the NSIDC ice concentration is declining on the Atlantic half of the ice pack.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-15 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4440.9   +1.3    +3.9    524.9  +46.3  -347.7    552.6   -7.2   -69.2
               Kara Sea             Barents Sea           Greenland Sea
   302.6  -82.9  -326.5     83.4   -3.8  -127.5    399.8  -41.0   -53.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   340.0   -1.8   -94.8      7.3   +4.2    +7.3    182.4  -15.3  -255.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   580.7  -16.5  -100.1    263.5  +19.7  -143.0    152.6  +22.8  -213.7
             Bering Sea          Sea of Okhotsk                   Lakes
     8.4   +0.0    +3.5     15.3   +1.1   +15.3    156.0  -15.0   +24.5
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   7857.4  -73.0 -1698.1

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3760.0  -81.1    +9.7    296.3  +14.3  -310.6    320.6  -24.5   -86.9
               Kara Sea             Barents Sea           Greenland Sea
   148.1  -35.9  -244.2     32.5   -2.3   -66.5    172.3  -24.8   -50.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   177.6   +2.0   -33.9      1.7   +0.8    +1.7     76.2   -6.7  -125.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   392.8  -10.0   -94.0    153.3   +3.0  -120.7     75.2   +4.5  -159.9
             Bering Sea          Sea of Okhotsk                   Lakes
     1.4   -0.1    +0.2      3.4   -0.1    +3.4     90.4   -0.1   +32.0
          Other regions       Total (ex. lakes)
     2.2   -0.1    +2.2   5613.6 -161.1 -1275.5


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: Steven on July 16, 2017, 07:16:58 PM
Sea ice area anomaly is currently  -1.28 million km2, which is 5th lowest for the date.  Average sea ice area during the first half of July 2017 was 6th lowest.  In the graph below I used data from Wipneus' site (https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_ant_nt_main.txt), which he calculates from NSIDC gridded sea ice concentration data.


(http://i.imgur.com/xPdJJhi.png)
Title: Re: 2017 sea ice area and extent data
Post by: jdallen on July 16, 2017, 07:22:04 PM
Very mixed picture. Large extent drops in Kara but rebounds in ESS and Chukchi. While UH AMSR2 "saw" concentration drops on the pacific side, the NSIDC ice concentration is declining on the Atlantic half of the ice pack.
Looks to me to me like lots of late FYI melting out within the pack proper, leaving behind the relict early FYI and sad bits of MYI behind.  Considering the condition of the ice I've been following in those areas, this comes as no surprise to me at all.
Title: Re: 2017 sea ice area and extent data
Post by: epiphyte on July 17, 2017, 08:15:01 AM

rebounds in ESS and Chukchi.


Yes - but that just seems to be the wrong word, somehow. It implies a strengthening or improvement in the state of the ice. Considering the direction it's headed and what's going to happen to it when it gets there, perhaps "diffusion" would be a better term?
Title: Re: 2017 sea ice area and extent data
Post by: oren on July 17, 2017, 08:31:44 AM

rebounds in ESS and Chukchi.


Yes - but that just seems to be the wrong word, somehow. It implies a strengthening or improvement in the state of the ice. Considering the direction it's headed and what's going to happen to it when it gets there, perhaps "diffusion" would be a better term?
A common behavior of extent (also area), especially in NSIDC, ice winking in and out of existence when it is marginal or covered with water (ponds, rain, storms). This only "matters" around the minimum.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 17, 2017, 09:01:12 AM

rebounds in ESS and Chukchi.


Yes - but that just seems to be the wrong word, somehow. It implies a strengthening or improvement in the state of the ice. Considering the direction it's headed and what's going to happen to it when it gets there, perhaps "diffusion" would be a better term?

My intended meaning was that extent rebounds, more specifically the extent as measured.

Like all measurements, those of extent and area do not perfectly match what we like them to be and must be interpreted. I think the chance that ice rebounded somehow is zero.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 17, 2017, 04:14:45 PM
Moderate extent drop and almost no net change in area.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-16 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4438.9   -2.0    +2.8    514.2  -10.7  -347.5    550.9   -1.7   -65.1
               Kara Sea             Barents Sea           Greenland Sea
   289.9  -12.7  -330.1     73.5   -9.9  -129.3    374.9  -24.9   -70.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   332.6   -7.4   -90.0      5.2   -2.1    +5.2    177.3   -5.1  -237.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   593.4  +12.7   -87.7    272.4   +8.8  -131.2    148.7   -3.9  -210.9
             Bering Sea          Sea of Okhotsk                   Lakes
     4.8   -3.6    -0.3     14.2   -1.1   +14.2    191.1  +35.1   +63.0
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   7793.8  -63.6 -1674.7

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3763.3   +3.3   +10.0    299.7   +3.4  -290.1    304.2  -16.4   -95.2
               Kara Sea             Barents Sea           Greenland Sea
   137.7  -10.4  -249.1     34.5   +2.0   -59.7    162.9   -9.4   -54.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   177.6   +0.0   -23.2      1.1   -0.5    +1.1     74.5   -1.7  -113.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   401.0   +8.2   -82.3    169.0  +15.7   -98.9     77.4   +2.2  -149.9
             Bering Sea          Sea of Okhotsk                   Lakes
     1.2   -0.3    -0.1      3.0   -0.4    +3.0     99.5   +9.2   +41.5
          Other regions       Total (ex. lakes)
     2.2   +0.0    +2.2   5609.4   -4.2 -1200.2


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 18, 2017, 07:21:01 PM
Small extent drop, and an uptick in area. The extent is affected by a particular large increase over Hudson, not likely to be real.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-17 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4435.0   -3.9    +0.1    515.8   +1.6  -342.1    539.2  -11.7   -69.6
               Kara Sea             Barents Sea           Greenland Sea
   243.2  -46.7  -371.3     69.0   -4.5  -126.2    361.0  -13.8   -75.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   328.3   -4.3   -81.9      7.8   +2.6    +7.8    221.9  +44.7  -172.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   617.9  +24.5   -60.8    262.9   -9.5  -137.0    127.0  -21.7  -227.8
             Bering Sea          Sea of Okhotsk                   Lakes
    13.2   +8.4    +8.6     20.2   +6.0   +20.2    190.5   -0.7   +64.7
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   7765.3  -28.5 -1624.9

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3790.8  +27.5   +47.7    287.4  -12.3  -291.4    302.1   -2.1   -88.5
               Kara Sea             Barents Sea           Greenland Sea
   119.7  -18.0  -259.7     26.9   -7.6   -62.7    156.2   -6.7   -57.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   180.8   +3.2   -11.7      1.5   +0.4    +1.5     94.0  +19.5   -82.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   418.0  +17.0   -54.9    169.0   +0.0   -91.3     66.9  -10.5  -152.1
             Bering Sea          Sea of Okhotsk                   Lakes
     2.8   +1.6    +1.6      4.7   +1.6    +4.7     96.8   -2.7   +40.7
          Other regions       Total (ex. lakes)
     2.2   -0.0    +2.2   5623.1  +13.7 -1094.6


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 19, 2017, 07:09:14 PM
Back in the fat centuries. The remaining ice in the Baffin region is taking a hit. CAB lost 60k in area.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-18 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4430.4   -4.6    -2.5    512.5   -3.3  -335.7    534.0   -5.1   -63.5
               Kara Sea             Barents Sea           Greenland Sea
   243.6   +0.5  -356.5     52.0  -17.0  -137.1    360.1   -0.9   -71.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   308.0  -20.3   -89.4      8.8   +1.1    +8.8    170.3  -51.6  -202.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   614.6   -3.3   -59.9    248.2  -14.6  -147.9    117.4   -9.6  -232.9
             Bering Sea          Sea of Okhotsk                   Lakes
    17.9   +4.7   +12.5     19.1   -1.2   +19.1    166.5  -24.0   +41.3
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   7640.0 -125.3 -1655.5

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3732.3  -58.5    +5.9    266.9  -20.5  -299.0    296.2   -6.0   -89.0
               Kara Sea             Barents Sea           Greenland Sea
   114.2   -5.5  -255.7     20.6   -6.3   -65.4    152.9   -3.3   -55.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   153.9  -26.9   -29.3      2.1   +0.5    +2.1     63.8  -30.2  -101.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   409.6   -8.5   -51.9    163.2   -5.8   -93.6     53.5  -13.5  -158.8
             Bering Sea          Sea of Okhotsk                   Lakes
     3.9   +1.1    +2.5      5.4   +0.7    +5.4     89.9   -6.9   +33.9
          Other regions       Total (ex. lakes)
     2.2   +0.0    +2.2   5440.7 -182.4 -1182.3


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: RoxTheGeologist on July 19, 2017, 07:13:55 PM

And the mystery ice in the Hudson winked back out of existence. +44, -44 over two days.
Title: Re: 2017 sea ice area and extent data
Post by: greatdying2 on July 19, 2017, 07:44:33 PM
I thought the +25 in the CAA yesterday might be noise too, but perhaps it is dispersion.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 20, 2017, 06:22:56 PM
A regional area century loss for the CAB today. Also notice the Greenland Sea extent. GS can be noisy, but UH AMSR2 sees the same drop there.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-19 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4425.8   -4.6    -7.0    499.8  -12.7  -341.2    511.8  -22.3   -77.6
               Kara Sea             Barents Sea           Greenland Sea
   234.1   -9.6  -350.9     52.7   +0.6  -129.5    306.3  -53.8  -117.3
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   335.8  +27.8   -47.4      6.2   -2.6    +6.2    165.0   -5.4  -189.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   600.8  -13.8   -71.3    231.7  -16.5  -160.7    120.1   +2.6  -223.0
             Bering Sea          Sea of Okhotsk                   Lakes
     3.6  -14.3    -1.9     21.9   +2.8   +21.9    168.1   +1.6   +39.6
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   7518.4 -121.6 -1686.1

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3621.7 -110.6   -99.6    252.5  -14.4  -300.8    282.8  -13.4   -92.9
               Kara Sea             Barents Sea           Greenland Sea
   108.7   -5.6  -249.5     19.7   -0.9   -61.6    143.3   -9.6   -61.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   148.5   -5.4   -26.3      1.7   -0.4    +1.7     61.8   -2.0   -95.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   406.4   -3.2   -52.2    155.4   -7.7   -94.8     48.4   -5.1  -158.0
             Bering Sea          Sea of Okhotsk                   Lakes
     1.0   -2.9    -0.4      6.1   +0.6    +6.1     87.8   -2.0   +30.5
          Other regions       Total (ex. lakes)
     2.3   +0.1    +2.3   5260.2 -180.5 -1283.0


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.
Title: Re: 2017 sea ice area and extent data
Post by: Hyperion on July 20, 2017, 08:29:15 PM
Wow. Largely compacting wind conditions and solid cloud cover, yet big purple blotches showing dropping concentration all through the heart of the pack. And 360 area and 240 extent in 48 hours.
So much for clouds preserving the Ice. If all those Typhoons in the Pacific start lobbing themselves into the fray it might get very messy indeed.
Title: Re: 2017 sea ice area and extent data
Post by: Wipneus on July 21, 2017, 07:27:13 PM
Most of the drop in Kara, followed by Kara and the Greenland Sea. The drop in the CAA is of course not to be taken too seriously.

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2017-07-20 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4412.7  -13.1   -19.0    488.3  -11.5  -347.3    515.4   +3.6   -66.7
               Kara Sea             Barents Sea           Greenland Sea
   170.3  -63.7  -403.3     62.9  +10.2  -112.3    278.1  -28.3  -139.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   325.2  -10.5   -42.2      8.3   +2.1    +8.3    176.4  +11.4  -159.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   563.0  -37.8  -104.4    238.8   +7.0  -150.6    127.7   +7.6  -209.6
             Bering Sea          Sea of Okhotsk                   Lakes
     5.4   +1.9    -0.1     19.3   -2.0   +19.3    167.0   -1.2   +38.7
          Other regions       Total (ex. lakes)
     2.9   +0.0    +2.9   7394.8 -123.1 -1724.4

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  3550.1  -71.6  -165.4    243.7   -8.8  -301.2    277.5   -5.3   -90.0
               Kara Sea             Barents Sea           Greenland Sea
    86.2  -22.5  -264.9     19.1   -0.6   -57.7    119.2  -24.1   -82.4
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   146.2   -2.3   -19.1      2.6   +1.0    +2.6     64.5   +2.7   -83.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   391.6  -14.8   -61.1    148.4   -7.0  -100.6     50.2   +1.8  -152.5
             Bering Sea          Sea of Okhotsk                   Lakes
     1.0   +0.0    -0.4      4.3   -1.6    +4.3     94.7   +6.8   +37.6
          Other regions       Total (ex. lakes)
     2.2   -0.0    +2.2   5106.9 -153.1 -1369.7


Delta map attached: red/blue means the concentration went below/over the 15% cut-off. Reddish/bluish means the concentration decreased/increased by more than 7%.