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Lord M Vader

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Re: 2014 sea ice area and extent data
« Reply #350 on: April 15, 2014, 06:41:35 PM »
The following list are the earliest dates when SIE due to JAXA have been less than:

13 mn km2: April 24
12 mn km2: May 13
11 mn km2: June 3
10 mn km2: June 17
 9 mn km2: July 1
 8 mn km2: July 10
 7 mn km2: July 19
 6 mn km2: August 3
 5 mn km2: August 10
 4 mn km2: August 23

May be interesting for this melt season to see how we are doing :)

Jim Pettit

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Re: 2014 sea ice area and extent data
« Reply #351 on: April 15, 2014, 08:00:17 PM »
and with that update the weekly average in CT SIA dropped under 13 Mkm2

145782 strikes me as a rather large one day drop for extent, much less area...

It's a big drop, for sure. In fact, it was the second largest drop in CT area since the last week of July, 2013. It also brought the decrease over the last three days to a very healthy 357,000 square kilometers, an average daily decrease of 119,000 km2. That's certainly not unheard of in early/mid April--but it's not exactly commonplace, either.

But of even greater interest to me is that 2014 extent is running 579,000 km2 lower than the same day in 2012.  That's an area of open ocean water about the size of California and Georgia combined--and that's a difference large enough to perhaps make a difference later on in the melt season...

BornFromTheVoid

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Re: 2014 sea ice area and extent data
« Reply #352 on: April 15, 2014, 08:47:31 PM »
I had a look at the 7 day extent loss categories (0-100k, 100-200k, etc) during the melt season how how their numbers have changed during the satellite record.
I split the melt season into March 8th (just to avoid issues with leap years) to September 30th, and looked at how many 7 day extent losses there were for each category, for each year.

First off, the number of 7 day periods with any melt is shown below.



A bit of variability, with 1999 being the main anomaly, and a slight upward trend, but nothing really significant.

Below is the number of 7 day extent losses between 0-500k.



The trend here is downward, with the first 5 years averaging 144.6 and the final 5 years averaging 122.2. The years 2012 and 1999 stand out more than any other.

Below is the number of 7 day extent losses greater than 500k.



Here we see a clear upward trend, with 2012 standing out like a sore thumb. The average of the first 5 years in 39.4, while the last 5 years is 59 (though possibly skewed by 2012) which represents an almost 50% increase in the number of 7 day periods where extent losses exceeded half a million km2.

But it seems that it's the extreme melt periods that are really growing. Below is the number of 7 day extent losses greater than 700k.



The trend is extremely clear, from an average of 4 for the first 5 years to 23.4 for the last 5 years, an increase of over 500%.

So it seems one of the main contributors to the decline in Summer/Autumn sea ice is the increase in extreme melt periods, rather than general increases or a lengthened melt season. This would suggest that as the pack has weakened, the unfavourable weather conditions can now cause rapid ice losses, rather than the moderate losses seen in the past. This explains the downward trend in low to moderate 7 day losses (trend strongest between 200 and 500k) and the upward trend in losses above 0.5 million km2, especially above 0.7.

I might post up a bit more on this later tonight or in the next few days, or if anyone wants any details for particular years, just ask.
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Jmo

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Re: 2014 sea ice area and extent data
« Reply #353 on: April 16, 2014, 03:41:41 AM »
Thanks BFTV.  Very interesting.

gerrit

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Re: 2014 sea ice area and extent data
« Reply #354 on: April 16, 2014, 10:11:03 AM »
This would suggest that as the pack has weakened, the unfavourable weather conditions can now cause rapid ice losses, rather than the moderate losses seen in the past.

In addition to a weakened pack, I think that unfavourable weather is also becoming more common. A very wavy jet stream / convoluted polar vortex will allow just as much mid-latitude warm air to enter the arctic as it allows cold arctic air to spill out. I also vaguely remember a discussion in 2012 that extreme summer and fall arctic lows / storms are becoming more common as more arctic ocean is exposed.

Jim Pettit

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Re: 2014 sea ice area and extent data
« Reply #355 on: April 16, 2014, 12:59:50 PM »
IJIS Extent:
13,427,583 km2 (15 April)
(2014 maximum: 14,448,416 km2 on 20 March).
Down 47,434 km2 from previous day.
Down 356,939 km2 over past seven days (daily average: -50,991 km2).
Down 449,591 km2 for the month of April (daily average: -29,973 km2).
293,101 km2 below 2000s average for this date.
331,448 km2 below 2010s average for this date.
217,098 km2 below 2013 value for this date.
622,947 km2 below 2012 value for this date.
Fourth lowest value for the date.
Fourth lowest April to-date average.


CT Area:
12,691,005 km2 (15 April [Day 0.2849])
(2014 maximum: 13,487,337 km2 on 22 March [Day 0.2192]).
Down 10,495 km2 from previous day.
Down 359,777 km2 over past seven days (daily average: -51,397 km2).
Down 417,500 km2 for the month of April (daily average: -27,833 km2).
172,885 km2 below 2000s average for this date.
204,044 km2 below 2010s average for this date.
383,304 km2 below 2013 value for this date.
424,465 km2 below 2012 value for this date.
Sixth lowest value for the date.
Sixth lowest April to-date average.

crandles

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Re: 2014 sea ice area and extent data
« Reply #356 on: April 16, 2014, 01:19:16 PM »
So it seems one of the main contributors to the decline in Summer/Autumn sea ice is the increase in extreme melt periods, rather than general increases or a lengthened melt season. This would suggest that as the pack has weakened, the unfavourable weather conditions can now cause rapid ice losses, rather than the moderate losses seen in the past. This explains the downward trend in low to moderate 7 day losses (trend strongest between 200 and 500k) and the upward trend in losses above 0.5 million km2, especially above 0.7.

I might post up a bit more on this later tonight or in the next few days, or if anyone wants any details for particular years, just ask.

I think it sensible to ask to what extent is the information obtained consistent with simple shift in average without changing distribution shape. ie like the following if you get what I mean


In this pic the red area is increased 100fold the orange area by about 4fold and if you go nearer the average you get 40% probability increased to 50% probability.

I am not sure I see anything to rule out "general increases" like this as you seem to think.

BornFromTheVoid

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Re: 2014 sea ice area and extent data
« Reply #357 on: April 16, 2014, 03:20:42 PM »
I think it sensible to ask to what extent is the information obtained consistent with simple shift in average without changing distribution shape. ie like the following if you get what I mean


In this pic the red area is increased 100fold the orange area by about 4fold and if you go nearer the average you get 40% probability increased to 50% probability.

I am not sure I see anything to rule out "general increases" like this as you seem to think.

Here's the distribution of losses for the first and last 7 years (to include the post 2007 shift)

First 7 years


Last 7 Years


There does seem to be the slight shift you suggested, but it ppear to me like the mid range has been squashed in order to accommodate more large losses more so. Though really, another decade of data would probably be needed to have much certainty either way.
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crandles

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Re: 2014 sea ice area and extent data
« Reply #358 on: April 16, 2014, 03:45:33 PM »
Thanks bftv.

The shape does seem to have changed rather than being just a simple general shift in the mean. Sorry, if I got it wrong but it did seem a possible interpretation. I think this new way is a better way of showing it. :)

We could wait for another decade of data, or maybe comparing first 12 years to last 12 years of data that we have got, would involve more data to allow the underlying pattern to be clearer?

Not sure, but perhaps if there is an x% increase in the average, each bands' range should be adjusted accordingly so that we are comparing to see if it is the same distribution rather than trying to figure out whether shift or distribution change is greater?

prometheus

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Re: 2014 sea ice area and extent data
« Reply #359 on: April 16, 2014, 05:05:26 PM »
The shapes are basically the same form. They appear to follow a Poisson distribution where the mean has shifted to higher melt values. Not a normal distribution, which is the bell curve you posted earlier.

MikeAinOz

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Re: 2014 sea ice area and extent data
« Reply #360 on: April 16, 2014, 11:10:35 PM »
The area under the curve must be increasing as well, surely the progressive change of the distribution of melt days and increasing area would be related to when actually run out of ice to melt. On first coffee mind just running...
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prometheus

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Re: 2014 sea ice area and extent data
« Reply #361 on: April 17, 2014, 03:58:07 AM »
The area under the curve must be increasing as well, surely the progressive change of the distribution of melt days and increasing area would be related to when actually run out of ice to melt. On first coffee mind just running...
Actually the area under the curves is about the same. The area has units of days, and is related to the length of the melt season, which hasn't changed by much. BFTV will be able to say for sure since he was the one to make those plots, but eyeballing both I see the total area as being 181 for the first 7 years and 184 for the last seven (a difference well under the possible error of my eyeball "measurement" :) ). This makes me think even more that the distribution of melt sizes follows a Poisson distribution. I'll take BFTVs numbers as I've eyeballed them (unless you want to post them) and take a closer look now.
« Last Edit: April 17, 2014, 04:05:11 AM by prometheus »

Jim Pettit

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Re: 2014 sea ice area and extent data
« Reply #362 on: April 17, 2014, 12:31:54 PM »
IJIS Extent:
13,321,362 km2 (16 April)
(1,127,054 lm2 below 2014 maximum of 14,448,416 km2 on 20 March.)
Down 106,221 km2 from previous day.
Down 412,030 km2 over past seven days (daily average: -58,861 km2).
Down 555,812 km2 for the month of April (daily average: -34,738 km2).
358,800 km2 below 2000s average for this date.
391,541 km2 below 2010s average for this date.
254,695 km2 below 2013 value for this date.
744,957 km2 below 2012 value for this date. (NOTE: that's an area 7% larger than the state of Texas)
Fourth lowest value for the date.
Fourth lowest April to-date average.


CT Area:
12,710,074 km2 (16 April [Day 0.2877])
(777,264 below 2014 maximum of 13,487,337 km2 on 22 March [Day 0.2192]).
Up 19,069 km2 from previous day.
Down 356,836 km2 over past seven days (daily average: -50,977 km2).
Down 398,431 km2 for the month of April (daily average: -24,902 km2).
104,039 km2 below 2000s average for this date.
186,302 km2 below 2010s average for this date.
338,167 km2 below 2013 value for this date.
413,570 km2 below 2012 value for this date.
Fifth lowest value for the date.
Sixth lowest April to-date average.

Apocalypse4Real

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Re: 2014 sea ice area and extent data
« Reply #363 on: April 17, 2014, 12:45:08 PM »
Jim,

Thanks for your ongoing work to post the CT Area and ISIJ daily changes. I regularly check your postings.

I have a request, I am presenting a paper on Friday and wanted to use your bar graph: Arctic Sea Ice Area Maximum/Minimum Day, plus Days Spent below 15-3 km2 1979 - 2013 (including Decadal Averages).

I was wondering if you might update that for 2014 since we have already reached sea ice maximum and lost over 1 million km2? It will be part of my argument on sea ice change and climate impacts section.

You will be cited as source, it is a faculty research presentation - so it is expected.

A4R



Jim Pettit

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Re: 2014 sea ice area and extent data
« Reply #364 on: April 17, 2014, 01:49:07 PM »
Jim,

Thanks for your ongoing work to post the CT Area and ISIJ daily changes. I regularly check your postings.

I have a request, I am presenting a paper on Friday and wanted to use your bar graph: Arctic Sea Ice Area Maximum/Minimum Day, plus Days Spent below 15-3 km2 1979 - 2013 (including Decadal Averages).

I was wondering if you might update that for 2014 since we have already reached sea ice maximum and lost over 1 million km2? It will be part of my argument on sea ice change and climate impacts section.

You will be cited as source, it is a faculty research presentation - so it is expected.

A4R

Thanks. And as fate would have it, I'm working on that piece right at the moment. I'll have it updated and uploaded within a few hours, and let you know...

BornFromTheVoid

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Re: 2014 sea ice area and extent data
« Reply #365 on: April 17, 2014, 07:00:02 PM »

We could wait for another decade of data, or maybe comparing first 12 years to last 12 years of data that we have got, would involve more data to allow the underlying pattern to be clearer?

Not sure, but perhaps if there is an x% increase in the average, each bands' range should be adjusted accordingly so that we are comparing to see if it is the same distribution rather than trying to figure out whether shift or distribution change is greater?

The first and last 12 show largely similar results, though the exceptionally large losses of recent years get averaged out to the point that they no longer appear.

The average 7 day loss has gone from 351 to 404k. I might try your second suggest soon then, I'll post it up when I'm done.

Actually the area under the curves is about the same. The area has units of days, and is related to the length of the melt season, which hasn't changed by much. BFTV will be able to say for sure since he was the one to make those plots, but eyeballing both I see the total area as being 181 for the first 7 years and 184 for the last seven (a difference well under the possible error of my eyeball "measurement" :) ). This makes me think even more that the distribution of melt sizes follows a Poisson distribution. I'll take BFTVs numbers as I've eyeballed them (unless you want to post them) and take a closer look now.

That's some good eyeballing! It was 182 and 184.
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

Jim Pettit

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Re: 2014 sea ice area and extent data
« Reply #366 on: April 17, 2014, 09:27:43 PM »
Jim,

Thanks for your ongoing work to post the CT Area and ISIJ daily changes. I regularly check your postings.

I have a request, I am presenting a paper on Friday and wanted to use your bar graph: Arctic Sea Ice Area Maximum/Minimum Day, plus Days Spent below 15-3 km2 1979 - 2013 (including Decadal Averages).

I was wondering if you might update that for 2014 since we have already reached sea ice maximum and lost over 1 million km2? It will be part of my argument on sea ice change and climate impacts section.

You will be cited as source, it is a faculty research presentation - so it is expected.

A4R

The image has been updated and uploaded; you can find it at http://iwantsomeproof.com/extimg/sia_max_min_plus_step_days.png

(Apologies for the delay; real world stuff intruded...)

crandles

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Re: 2014 sea ice area and extent data
« Reply #367 on: April 18, 2014, 12:15:36 AM »

The image has been updated and uploaded; you can find it at http://iwantsomeproof.com/extimg/sia_max_min_plus_step_days.png

(Apologies for the delay; real world stuff intruded...)

Could you check the 1979 minimum on this image.
The minimum area looks to be
1979.7233   0.4330184   5.3067255   4.8737073
and the graph indicates 5.306 as the minimum

.7233 *365 = approx day 264, while graph seems to indicate minimum occurred about day 277.

MikeAinOz

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Re: 2014 sea ice area and extent data
« Reply #368 on: April 18, 2014, 01:06:50 AM »
Looking at the comments of Prometheus and BFTV, I realize that the 7 day melt graph is actually a probability distribution. To me, about 40 years since I did any serious mathematics, this means that if the distribution continues to move to the right, eventually it will melt all the sea ice. This raises more questions in my mind than answers  :( . Is there a suitable dataset so I can play with the distribution?
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Jim Pettit

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Re: 2014 sea ice area and extent data
« Reply #369 on: April 18, 2014, 12:47:15 PM »
IJIS Extent:
13,255,763 km2 (17 April)
(1,192,653 km2 below 2014 maximum of 14,448,416 km2 on 20 March.)
Down 65,599 km2 from previous day.
Down 410,526 km2 over past seven days (daily average: -58,647 km2).
Down 621,411 km2 for the month of April (daily average: -36,554 km2).
378,749 km2 below 2000s average for this date.
412,595 km2 below 2010s average for this date.
269,028 km2 below 2013 value for this date.
783,459 km2 below 2012 value for this date. (NOTE: that's an area 12% larger than the state of Texas)
Third lowest value for the date.
20th day this year in third place, and 42nd day among the three lowest.
Fourth lowest April to-date average.


CT Area:
12,603,444 km2 (17 April [Day 0.2904])
(883,893 km2 below 2014 maximum of 13,487,337 km2 on 22 March [Day 0.2192]).
Down 106,629 km2 from previous day.
Down 496,895 km2 over past seven days (daily average: -70,985 km2).
Down 505,060 km2 for the month of April (daily average: -29,709 km2).
166,612 km2 below 2000s average for this date.
237,908 km2 below 2010s average for this date.
382,901 km2 below 2013 value for this date.
509,100 km2 below 2012 value for this date.
Fourth lowest value for the date.
Sixth lowest April to-date average.
« Last Edit: April 18, 2014, 01:47:11 PM by Jim Pettit »

Jim Pettit

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Re: 2014 sea ice area and extent data
« Reply #370 on: April 18, 2014, 12:59:09 PM »
Could you check the 1979 minimum on this image.
The minimum area looks to be
1979.7233   0.4330184   5.3067255   4.8737073
and the graph indicates 5.306 as the minimum

.7233 *365 = approx day 264, while graph seems to indicate minimum occurred about day 277.

Thanks; you are correct. I've made the change and will upload the revised chart when the 0.2904 numbers come out. Not sure how that happened, though it's been intact since I first created this a few years ago. Hmmm.... Anyway, I'm now going through all the maxima to be sure they're correct.

Again, thanks for pointing that out.

Apocalypse4Real

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Re: 2014 sea ice area and extent data
« Reply #371 on: April 18, 2014, 02:06:01 PM »
Jim,

The update is invaluable, and many thanks, I am using it in a presentation this morning, and you will receive credit.

A4R

Wipneus

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Re: 2014 sea ice area and extent data
« Reply #372 on: April 18, 2014, 04:23:43 PM »
As NSIDC takes a dive today, CT Area will score a double century this  Sunday (or very nearly so):

19.4   20.4
-49.7  -211.1

Buddy

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Re: 2014 sea ice area and extent data
« Reply #373 on: April 18, 2014, 05:23:27 PM »
The month of May is really setting up to be ugly.....  Northern Russia has been much warmer than usual....which will not be good for the ice along Russia.  The next week in the Arctic is going to be much warmer than usual....so that will help to set the table for May.

Not pretty..... :'(
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BornFromTheVoid

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Re: 2014 sea ice area and extent data
« Reply #374 on: April 19, 2014, 04:18:04 PM »
Another big drop for the NSIDC extent, -119k down to 13,790,010km2. That's 277k in 2 days, and 544k in the last week.

2012 didn't reach our current extent until April 30th!
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Re: 2014 sea ice area and extent data
« Reply #375 on: April 19, 2014, 05:21:53 PM »
2012 didn't reach our current extent until April 30th!

In the IJIS/JAXA data 2012 had 5 days of record daily highs between April 16 and 21st before dropping precipitously the following week.

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Re: 2014 sea ice area and extent data
« Reply #376 on: April 20, 2014, 01:48:15 PM »
The area under the curve must be increasing as well, surely the progressive change of the distribution of melt days and increasing area would be related to when actually run out of ice to melt. On first coffee mind just running...
Actually the area under the curves is about the same. The area has units of days, and is related to the length of the melt season, which hasn't changed by much. BFTV will be able to say for sure since he was the one to make those plots, but eyeballing both I see the total area as being 181 for the first 7 years and 184 for the last seven (a difference well under the possible error of my eyeball "measurement" :) ). This makes me think even more that the distribution of melt sizes follows a Poisson distribution. I'll take BFTVs numbers as I've eyeballed them (unless you want to post them) and take a closer look now.


The Poisson distribution comes about from the time spacing between events which arrive randomly; i can't see a physical understanding of 7 day melt averages following this distribution.

EDIT: http://www.math.uah.edu/stat/poisson/index.html is a good link for understanding the poisson process (and the related exponential, poisson, and gamma distributions)

(the link i originally posted was http://www.umass.edu/wsp/resources/poisson/ which provides an overview of the distribution )
« Last Edit: April 21, 2014, 01:47:41 AM by andy_t_roo »

Jim Pettit

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Re: 2014 sea ice area and extent data
« Reply #377 on: April 20, 2014, 02:05:09 PM »
IJIS Extent:
13,193,343 km2 (19 April)
Down 1,255,073 km2 (8.69%) from 2014 maximum of 14,448,416 km2 on 20 March.
Down 37,686 km2 from previous day.
Down 351,195 km2 over past seven days (daily average: -50,171 km2).
Down 683,831 km2 for the month of April (daily average: -35,991 km2).
383,275 km2 below 2000s average for this date.
402,739 km2 below 2010s average for this date.
227,891 km2 below 2013 value for this date.
794,930 km2 below 2012 value for this date.
Second lowest value for the date.
Twelfth day this year at second lowest; 23rd day among two lowest; 44th day among three lowest
Fourth lowest April to-date average.


CT Area:
12,551,008 km2 (18 April [Day 0.2931])
Down 936,329 km2 (6.94%) from 2014 maximum of 13,487,337 km2 on 22 March [Day 0.2192].
Down 52,436 km2 from previous day.
Down 507,960 km2 over past seven days (daily average: -72,566 km2).
Down 557,496 km2 for the month of April (daily average: -30,972 km2).
188,197 km2 below 2000s average for this date.
266,998 km2 below 2010s average for this date.
410,830 km2 below 2013 value for this date.
574,394 km2 below 2012 value for this date.
Third lowest value for the date.
14th day this year at third lowest; 40th day this year among three lowest
Sixth lowest April to-date average.

Jim Pettit

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Re: 2014 sea ice area and extent data
« Reply #378 on: April 21, 2014, 12:36:40 PM »
IJIS Extent:
13,177,428 km2 (20 April)
Down 1,270,988 km2 (8.8%) from 2014 maximum of 14,448,416 km2 on 20 March.
Down 15,915 km2 from previous day.
Down 312,345 km2 over past seven days (daily average: -44,621 km2).
Down 699,746 km2 for the month of April (daily average: -34,987 km2).
377,984 km2 below 2000s average for this date.
381,695 km2 below 2010s average for this date.
216,136 km2 below 2013 value for this date.
754,586 km2 below 2012 value for this date.
Second lowest value for the date.
13th day this year at second lowest; 24th day among lowest two; 45th day among lowest three
Third lowest April to-date average.


CT Area:
12,171,398 km2 (20 April [Day 0.2986])
Down 1,315,939 km2 (9.76%) from 2014 maximum of 13,487,337 km2 on 22 March [Day 0.2192].
Down 184,861 km2 from previous day.
Down 675,884 km2 over past seven days (daily average: -96,555 km2).
Down 937,106 km2 for the month of April (daily average: -46,855 km2).
477,325 km2 below 2000s average for this date.
504,649 km2 below 2010s average for this date.
642,682 km2 below 2013 value for this date.
842,248 km2 below 2012 value for this date.
Second lowest value for the date.
16th day this year at second lowest; 28th day among lowest two; 42nd day among lowest three
Fourth lowest April to-date average.
« Last Edit: April 21, 2014, 02:17:44 PM by Jim Pettit »

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Re: 2014 sea ice area and extent data
« Reply #379 on: April 21, 2014, 02:40:28 PM »
CT: 12,171,398

Last 2 falls were 195k and 185k.


So now just 38k above 2007 lowest.

Would need 102k fall with next data to equal lowest for that day
or 131k fall over 2 days to equal lowest for that day

(Edit: With Wipneus posting -142k on his AMSR2 data, that 102k fall looks likely.)


Pmt111500

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Re: 2014 sea ice area and extent data
« Reply #380 on: April 21, 2014, 03:56:53 PM »
and now 2014 has 5 days of being the biggest loser of the 1979-2014 lot, this happens to be the same number that it is the smallest loser, but things may change.

Wipneus

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Re: 2014 sea ice area and extent data
« Reply #381 on: April 21, 2014, 04:18:08 PM »
CT: 12,171,398

(Edit: With Wipneus posting -142k on his AMSR2 data, that 102k fall looks likely.)

I am afraid not  :(

Estimated changes for the next two days (Tue,Wed):

 -7.4  +20.3


crandles

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Re: 2014 sea ice area and extent data
« Reply #382 on: April 21, 2014, 07:00:37 PM »
CT: 12,171,398

(Edit: With Wipneus posting -142k on his AMSR2 data, that 102k fall looks likely.)

I am afraid not  :(

Estimated changes for the next two days (Tue,Wed):

 -7.4  +20.3

Oh well, maybe NSIDC can manage a 25k fall.

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Re: 2014 sea ice area and extent data
« Reply #383 on: April 22, 2014, 12:49:26 PM »
IJIS Extent:
13,174,019 km2 (21 April)
Down 1,274,397 km2 (8.82%) from 2014 maximum of 14,448,416 km2 on 20 March.
Down 3,409 km2 from previous day.
Down 300,998 km2 over past seven days (daily average: -43,000 km2).
Down 703,155 km2 for the month of April (daily average: -33,484 km2).
356,905 km2 below 2000s average for this date.
371,731 km2 below 2010s average for this date.
230,145 km2 below 2013 value for this date.
741,422 km2 below 2012 value for this date.
Third lowest value for the date.
22nd day this year at third lowest; 45th day, and fifth consecutive day, among lowest three
Third lowest April to-date average.

BornFromTheVoid

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Re: 2014 sea ice area and extent data
« Reply #384 on: April 22, 2014, 01:52:04 PM »
Update for the week to April 19th

The current 1 day extent is 13,780,490km2, while the 5 day mean is on 13,934,950km2

The daily anomaly (compared to 79-11) is at -759,180km2, an increase from -648,310km2 last week. The anomaly compared to the 07, 11 and 12 average is at -294,370km2, a change from -89,870km2. We're currently 3rd lowest on record, compared to 4th lowest last week.

The average daily change over the last 7 days was -53.0k/day, compared to the long term average of -37.4k/day, and the average of the last 5 years of -34.3k/day.

The average long term change over the next week is -38.3k/day, with the average of the last 5 years being -39.5k/day.

The loss so far this April is the 13th largest on record. The achieve the largest April loss on record, an average of -87.4k/day is required, while the smallest April loss requires +8.1k/day for the remainder of the month.



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ChrisReynolds

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Re: 2014 sea ice area and extent data
« Reply #385 on: April 22, 2014, 07:40:39 PM »
BFTV,

Thanks for those distributions. In terms of temperature (Hansen's Climate Dice paper) what is happening is a flattening and upward shift due to amplification effects (snow retreat and soil drying).

A similar amplification effect may be happening in terms of sea ice because as the ice gets thinner potential for ice albedo feedback to open new open water increases.

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Re: 2014 sea ice area and extent data
« Reply #386 on: April 23, 2014, 10:36:28 AM »
for historical perspctive, one way to look at seasonal changes happening over the years is to check how much the monthly smoothed averages of CT SIA drop/gain differ between themselves, it appears 2014 is somewhat curious if looking only decadal values. maybe I should do this also for every year (oops, or do it again). February in the Arctic was quite abnormal in 2014 compared to most other years. (looking at similar graphs for every year in the record yields only 3 as abnormal years in Feb, 1989, 2005, and 2006 with 1988 and 1996 closely following.( maby there's a link to piomas drops)

(connection to the net broke so lost the longer text) (modified to add similarly built, full image of the years.)
« Last Edit: April 23, 2014, 12:19:06 PM by Pmt111500 »

Jim Pettit

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Re: 2014 sea ice area and extent data
« Reply #387 on: April 23, 2014, 12:47:42 PM »
IJIS Extent:
13,115,859 km2 (22 April)
Down 1,332,557 km2 (9.22%) from 2014 maximum of 14,448,416 km2 on 20 March.
Down 58,160 km2 from previous day.
Down 311,724 km2 over past seven days (daily average: -44,532 km2).
Down 761,315 km2 for the month of April (daily average: -34,605 km2).
377,843 km2 below 2000s average for this date.
395,108 km2 below 2010s average for this date.
293,496 km2 below 2013 value for this date.
733,902 km2 below 2012 value for this date.
Third lowest value for the date.
23rd day this year at third lowest; 47th day, and sixth consecutive day, among lowest three.
Fourth lowest April to-date average.


CT Area:
12,179,074 km2 (22 April [Day 0.3041])
Down 1,308,263 km2 (9.7%) from 2014 maximum of 13,487,337 km2 on 22 March [Day 0.2192].
Up 18,706 km2 from previous day.
Down 511,931 km2 over past seven days (daily average: -73,133 km2).
Down 929,430 km2 for the month of April (daily average: -42,247 km2).
434,531 km2 below 2000s average for this date.
444,348 km2 below 2010s average for this date.
578,502 km2 below 2013 value for this date.
811,585 km2 below 2012 value for this date.
Second lowest value for the date.
17th day this year at second lowest; 29th day this year among lowest two; 44th day, and fifth consecutive day, among lowest three
Fourth lowest April to-date average.
« Last Edit: April 23, 2014, 02:16:39 PM by Jim Pettit »

Pmt111500

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Re: 2014 sea ice area and extent data
« Reply #388 on: April 23, 2014, 04:09:39 PM »
and monthly CT SIA average dropped below 13 Mkm2
« Last Edit: April 23, 2014, 05:25:12 PM by Pmt111500 »

Jim Pettit

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Re: 2014 sea ice area and extent data
« Reply #389 on: April 24, 2014, 05:15:54 PM »
IJIS Extent:
13,097,680 km2 (23 April)
Down 1,350,736 km2 (9.35%) from 2014 maximum of 14,448,416 km2 on 20 March.
Down 18,179 km2 from previous day.
Down 223,682 km2 over past seven days (daily average: -31,955 km2).
Down 779,494 km2 for the month of April (daily average: -33,891 km2).
354,995 km2 below 2000s average for this date.
364,231 km2 below 2010s average for this date.
257,529 km2 below 2013 value for this date.
637,757 km2 below 2012 value for this date.
Third lowest value for the date.
24th day this year at third lowest; 48th day, and seventh consecutive day, among lowest three
Fourth lowest April to-date average.


CT Area:
12,196,437 km2 (23 April [Day 0.3069])
Down 1,290,900 km2 (9.57%) from 2014 maximum of 13,487,337 km2 on 22 March [Day 0.2192].
Up 17,363 km2 from previous day.
Down 513,637 km2 over past seven days (daily average: -73,377 km2).
Down 912,067 km2 for the month of April (daily average: -39,655 km2).
381,459 km2 below 2000s average for this date.
409,309 km2 below 2010s average for this date.
597,015 km2 below 2013 value for this date.
765,698 km2 below 2012 value for this date.
Second lowest value for the date.
18th day this year at second lowest; 30th day this year among lowest two; 45th day, and sixth consecutive day, among lowest three
Sixth lowest April to-date average.
« Last Edit: April 24, 2014, 07:24:19 PM by Jim Pettit »

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Re: 2014 sea ice area and extent data
« Reply #390 on: April 25, 2014, 01:16:48 PM »
IJIS Extent:
13,068,484 km2 (24 April)
Down 1,379,932 km2 (9.55%) from 2014 maximum of 14,448,416 km2 on 20 March.
Down 29,196 km2 from previous day.
Down 187,279 km2 over past seven days (daily average: -26,754 km2).
Down 808,690 km2 for the month of April (daily average: -33,695 km2).
334,166 km2 below 2000s average for this date.
337,439 km2 below 2010s average for this date.
186,979 km2 below 2013 value for this date.
598,437 km2 below 2012 value for this date.
Third lowest value for the date.
25th day this year at third lowest; 49th day, and eighth consecutive day, among lowest three
Fourth lowest April to-date average.


CT Area:
12,177,609 km2 (24 April [Day 0.3096])
Down 1,309,728 km2 (9.71%) from 2014 maximum of 13,487,337 km2 on 22 March [Day 0.2192].
Down 18,828 km2 from previous day.
Down 425,835 km2 over past seven days (daily average: -60,834 km2).
Down 930,895 km2 for the month of April (daily average: -38,787 km2).
364,429 km2 below 2000s average for this date.
377,118 km2 below 2010s average for this date.
497,707 km2 below 2013 value for this date.
752,878 km2 below 2012 value for this date.
Second lowest value for the date.
19th day this year at second lowest; 31st day this year among lowest two; 46th day, and seventh consecutive day, among lowest three
Fourth lowest April to-date average.
« Last Edit: April 25, 2014, 04:47:52 PM by Jim Pettit »

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Re: 2014 sea ice area and extent data
« Reply #391 on: April 26, 2014, 01:25:39 PM »
IJIS Extent:
13,036,431 km2 (25 April)
Down 1,411,985 km2 (9.77%) from 2014 maximum of 14,448,416 km2 on 20 March.
Down 32,053 km2 from previous day.
Down 194,598 km2 over past seven days (daily average: -27,800 km2).
Down 840,743 km2 for the month of April (daily average: -33,630 km2).
326,898 km2 below 2000s average for this date.
283,589 km2 below 2010s average for this date.
86,260 km2 below 2013 value for this date.
524,269 km2 below 2012 value for this date.
Second lowest value for the date.
26th day this year at third lowest; 50th day, and ninth consecutive day, among lowest three
Fourth lowest April to-date average.

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Re: 2014 sea ice area and extent data
« Reply #392 on: April 27, 2014, 01:22:54 PM »
IJIS Extent:
12,978,878 km2 (26 April)
Down 1,469,538 km2 (10.17%) from 2014 maximum of 14,448,416 km2 on 20 March.
Down 57,553 km2 from previous day.
Down 214,465 km2 over past seven days (daily average: -30,638 km2).
Down 898,296 km2 for the month of April (daily average: -34,550 km2).
336,180 km2 below 2000s average for this date.
258,654 km2 below 2010s average for this date.
62,286 km2 below 2013 value for this date.
458,028 km2 below 2012 value for this date.
Fourth lowest value for the date.
Fourth lowest April to-date average.


CT Area:
12,279,904 km2 (26 April [Day 0.3151])
Down 1,207,433 km2 (8.95%) from 2014 maximum of 13,487,337 km2 on 22 March [Day 0.2192].
Up 79,906 km2 from previous day.
Down 76,355 km2 over past seven days (daily average: -10,908 km2).
Down 828,600 km2 for the month of April (daily average: -31,869 km2).
193,051 km2 below 2000s average for this date.
165,969 km2 below 2010s average for this date.
184,823 km2 below 2013 value for this date.
586,361 km2 below 2012 value for this date.
Seventh lowest value for the date.
Fourth lowest April to-date average.
« Last Edit: April 27, 2014, 07:34:57 PM by Jim Pettit »

crandles

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Re: 2014 sea ice area and extent data
« Reply #393 on: April 27, 2014, 03:03:32 PM »
CT area
2014.3151  -0.6334613  12.2799044  12.9133654

80k up on yesterday.
up 108k on 6 days ago.  :o

Shared Humanity

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Re: 2014 sea ice area and extent data
« Reply #394 on: April 27, 2014, 04:10:39 PM »
CT area
2014.3151  -0.6334613  12.2799044  12.9133654

80k up on yesterday.
up 108k on 6 days ago.  :o

SIE is continuing with a slow decline. Compaction? Refreeze of open water in the CAB and other places?

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Re: 2014 sea ice area and extent data
« Reply #395 on: April 27, 2014, 04:14:40 PM »
Update for the week to April 26th

The current 1 day extent is 13,716,920km2, while the 5 day mean is on 13,771,800km2

The daily anomaly (compared to 79-11) is at -554,870km2, a decrease from -759,180km2 last week. The anomaly compared to the 07, 11 and 12 average is at -89,330km2, a change from -294,370km2. We're currently 4th lowest on record, compared to 3rd lowest last week.

The average daily change over the last 7 days was -9.1k/day, compared to the long term average of -38.3k/day, and the average of the last 5 years of -39.5k/day.

The average long term change over the next week is -58.2k/day, with the average of the last 5 years being -68.6k/day.

The loss so far this April is the 12th smallest on record. To achieve the largest April loss on record, an average of -224,350k/day is required, while the smallest April loss requires +38.1k/day for the remainder of the month.



I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

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Re: 2014 sea ice area and extent data
« Reply #396 on: April 28, 2014, 09:41:46 AM »
SIE is continuing with a slow decline. Compaction? Refreeze of open water in the CAB and other places?

It were "torch" :D

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Re: 2014 sea ice area and extent data
« Reply #397 on: April 28, 2014, 01:06:45 PM »
IJIS Extent:
12,930,713 km2 (27 April)
Down 1,517,703 km2 (10.5%) from 2014 maximum of 14,448,416 km2 on 20 March.
Down 48,165 km2 from previous day.
Down 246,715 km2 over past seven days (daily average: -35,245 km2).
Down 946,461 km2 for the month of April (daily average: -35,054 km2).
340,449 km2 below 2000s average for this date.
253,045 km2 below 2010s average for this date.
91,858 km2 below 2013 value for this date.
405,708 km2 below 2012 value for this date.
Fourth lowest value for the date.
Fourth lowest April to-date average.

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Re: 2014 sea ice area and extent data
« Reply #398 on: April 29, 2014, 12:08:33 PM »
IJIS Extent:
12,928,262 km2 (28 April)
Down 1,520,154 km2 (10.52%) from 2014 maximum of 14,448,416 km2 on 20 March.
Down 2,451 km2 from previous day.
Down 245,757 km2 over past seven days (daily average: -35,108 km2).
Down 948,912 km2 for the month of April (daily average: -33,890 km2).
296,886 km2 below 2000s average for this date.
217,548 km2 below 2010s average for this date.
57,352 km2 below 2013 value for this date.
362,352 km2 below 2012 value for this date.
Fourth lowest value for the date.
Fourth lowest April to-date average.


CT Area:
12,294,369 km2 (28 April [Day 0.3206])
Down 1,192,968 km2 (8.85%) from 2014 maximum of 13,487,337 km2 on 22 March [Day 0.2192].
Down 16,844 km2 from previous day.
Up 134,001 km2 over past seven days (daily average: 19,143 km2).
Down 814,136 km2 for the month of April (daily average: -29,076 km2).
48,944 km2 below 2000s average for this date.
12,102 km2 above 2010s average for this date.
57,614 km2 above 2013 value for this date.
356,453 km2 below 2012 value for this date.
Tenth lowest value for the date.
Fourth lowest April to-date average.
« Last Edit: April 29, 2014, 01:41:45 PM by Jim Pettit »

Jim Pettit

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Re: 2014 sea ice area and extent data
« Reply #399 on: April 30, 2014, 12:53:16 PM »
IJIS Extent:
12,928,298 km2 (29 April)
Down 1,520,118 km2 (10.52%) from 2014 maximum of 14,448,416 km2 on 20 March.
Up 36 km2 from previous day.
Down 187,561 km2 over past seven days (daily average: -26,794 km2).
Down 948,876 km2 for the month of April (daily average: -32,720 km2).
256,786 km2 below 2000s average for this date.
170,409 km2 below 2010s average for this date.
12,059 km2 below 2013 value for this date.
305,225 km2 below 2012 value for this date.
Fourth lowest value for the date.
Fourth lowest April to-date average.


CT Area:
12,272,500 km2 (29 April [Day 0.3232])
Down 1,214,837 km2 (9.01%) from 2014 maximum of 13,487,337 km2 on 22 March [Day 0.2192].
Down 21,869 km2 from previous day.
Up 93,426 km2 over past seven days (daily average: 13,347 km2).
Down 836,004 km2 for the month of April (daily average: -28,828 km2).
23,567 km2 below 2000s average for this date.
54,201 km2 above 2010s average for this date.
79,309 km2 above 2013 value for this date.
224,565 km2 below 2012 value for this date.
Ninth lowest value for the date.
Fifth lowest April to-date average.
« Last Edit: April 30, 2014, 01:55:05 PM by Jim Pettit »