Arctic Sea Ice : Forum

Cryosphere => Arctic sea ice => Topic started by: Neven on January 06, 2016, 12:01:15 AM

Title: 2016 sea ice area and extent data
Post by: Neven on January 06, 2016, 12:01:15 AM
This thread replaces the 2015 version (http://forum.arctic-sea-ice.net/index.php/topic,1112.1050.html).

Last comment:

Update for the week to January 2nd

The current 5 day mean is on 12,797,800km2 while the 1 day extent is at 12,811,000km2.

The daily anomaly (compared to 81-10) is at -921,490km2, an increase from -775,320km2 last week. The anomaly compared to the 07, 11 and 12 average is at -206,470km2, an increase from -70,13km2 last week. We're currently 2nd lowest on record, up from 4th lowest last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FWm1SxDf.png&hash=7bc543ea24c586e2e66833b6a13a4565)

The average daily change over the last 7 days was +33.2k/day, compared to the long term average of +54.1k/day, and the 07, 11 and 12 average of +52.7k/day.
The average long term change over the next week is +53.8k/day, with the 07, 11, and 12 average being +51.8k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FwNSmZlT.png&hash=81cf67e8e515b8720669eeaae4f68ff3)

The increase so far this January is the smallest on record. To achieve the smallest monthly gain, an increase of less than 28.1k/day is required, while the largest monthly gain requires an increase of at least 61.6k/day and an average gain requires an increase of 45.0k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FwH2ivtw.png&hash=af3ead75444ee84520a86f4e84c36c1c)

The increase this December was the 18th largest on record, while the average extent was the 5th smallest on record.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FuKVQH0g.png&hash=b479d474264e55a4784949223dab0b04)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FMtWs2UP.png&hash=843e2fdd4467bec95918b66549c3a770)

Have at it.
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on January 06, 2016, 03:30:02 AM
Becoming worst (or better, depending of the person that is writing). Too early for conclusions, but impressive. 1st. lowest on record.
Title: Re: 2016 sea ice area and extent data
Post by: plg on January 07, 2016, 06:58:32 AM
The recent above freezing temperature in the Arctic obviously had a disastrous effect...

We are in deep trouble ;-)
Title: Re: 2016 sea ice area and extent data
Post by: crandles on January 07, 2016, 11:06:24 AM
We are in deep trouble ;-)

Yes, imagine having to live through 2017 twice  ;) :P :-\
Title: Re: 2016 sea ice area and extent data
Post by: DoomInTheUK on January 07, 2016, 11:18:32 AM
We are in deep trouble ;-)

Yes, imagine having to live through 2017 twice  ;) :P :-\

Probably better to live through 2017 twice than 2017 once and then put up with 2018.  :o
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on January 07, 2016, 11:32:06 AM
The recent above freezing temperature in the Arctic obviously had a disastrous effect...
We are in deep trouble ;-)

Just a little side note. I think we should see these things neutrally and not make them troublesome or a gift.
some regions will suffer and others will benefit while transitions will always cause disruptions. that's how things are and have always been. further i believe that the term "manmade" even though it's correct IMO, hence valid, does as well not mean good or bad, because we are a part of nature like any other factor involved. the right attempt would be to adapt and to take measures and deal with the consequences by reducing them and/or getting them under control, but not make things evil. i for my part enjoy the ever getting warmer winters and i'm living ocean side, hence not away from it all. this topic could fill many books hence it's not easy to make a good statement in a few lines but i neither like the denialists nore the doomsday approach, that's what i tried to express with this post
Title: Re: 2016 sea ice area and extent data
Post by: epiphyte on January 07, 2016, 03:48:52 PM
The recent above freezing temperature in the Arctic obviously had a disastrous effect...

We are in deep trouble ;-)

OMG. It seems that the earth turned upside down _and_ the Sun exploded - all in one day. Can't believe I missed that ;)
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on January 07, 2016, 04:41:41 PM
The recent above freezing temperature in the Arctic obviously had a disastrous effect...

We are in deep trouble ;-)

I'm feeling powerful! I'm sure that they read my new Forum signature and they made the correction!

Let's wait a couple of days and IPCC will do the same  ;) :D
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on January 07, 2016, 07:42:04 PM
I´m done with my new 2016 Forum signature, so I post an image of it, just to keep it that way. Sorry for all that changes in the last couple of days.

Here is what I think: Extent and area are great to follow the Arctic sea ice on a daily basis, but it is a huge mistake if we use them to forecast Arctic sea ice. It is the difference on talking about Arctic Ice-free on 2025 or 2100. We should push to remove this practice in institutions like the IPCC and the NSIDC, because then they underestimate the real speed of ASI change.

Have a good day and looking forward to participate on this forum on 2016!
Title: Re: 2016 sea ice area and extent data
Post by: gideonlow on January 08, 2016, 06:00:20 AM
The recent above freezing temperature in the Arctic obviously had a disastrous effect...
We are in deep trouble ;-)

Just a little side note. I think we should see these things neutrally and not make them troublesome or a gift.
some regions will suffer and others will benefit while transitions will always cause disruptions. that's how things are and have always been. further i believe that the term "manmade" even though it's correct IMO, hence valid, does as well not mean good or bad, because we are a part of nature like any other factor involved. the right attempt would be to adapt and to take measures and deal with the consequences by reducing them and/or getting them under control, but not make things evil. i for my part enjoy the ever getting warmer winters and i'm living ocean side, hence not away from it all. this topic could fill many books hence it's not easy to make a good statement in a few lines but i neither like the denialists nore the doomsday approach, that's what i tried to express with this post

Unfortunately, trying to maintain a warm-and-fuzzy "let's not take it so seriously" attitude will do absolutely nothing to reduce the very real and catastrophic effects, the worst of which will be felt not by ocean-side dwelling First-worlders, but by 100's of millions of developing world people.  The world will not end, but from a human civilization perspective (especially those with less means to adapt) "doomsday" isn't so far from the truth. 

The problem is that such complacency leads to reduced action to avert more of the worst consequences.  We are already so, so far behind where we need to be . . . A strong sense of urgency is vital if our species hopes to survive in the future with anything close to the lifestyles most of us commenters are accustomed to.
Title: Re: 2016 sea ice area and extent data
Post by: plg on January 08, 2016, 10:12:14 AM
The recent above freezing temperature in the Arctic obviously had a disastrous effect...
We are in deep trouble ;-)

Just a little side note. I think we should see these things neutrally and not make them troublesome or a gift.
some regions will suffer and others will benefit while transitions will always cause disruptions. that's how things are and have always been. further i believe that the term "manmade" even though it's correct IMO, hence valid, does as well not mean good or bad, because we are a part of nature like any other factor involved. the right attempt would be to adapt and to take measures and deal with the consequences by reducing them and/or getting them under control, but not make things evil. i for my part enjoy the ever getting warmer winters and i'm living ocean side, hence not away from it all. this topic could fill many books hence it's not easy to make a good statement in a few lines but i neither like the denialists nore the doomsday approach, that's what i tried to express with this post

Unfortunately, trying to maintain a warm-and-fuzzy "let's not take it so seriously" attitude will do absolutely nothing to reduce the very real and catastrophic effects, the worst of which will be felt not by ocean-side dwelling First-worlders, but by 100's of millions of developing world people.  The world will not end, but from a human civilization perspective (especially those with less means to adapt) "doomsday" isn't so far from the truth. 

The problem is that such complacency leads to reduced action to avert more of the worst consequences.  We are already so, so far behind where we need to be . . . A strong sense of urgency is vital if our species hopes to survive in the future with anything close to the lifestyles most of us commenters are accustomed to.

My attempt at humor at Cryosphere's data glitches have evolved into something more serious and probably off topic but will add one response.

I will just add that a year or so ago I saw some posts which may be relevant; summarizing from memory:

On the one hand it exciting to see unfolding drama in the Arctic, and even "hoping" for major melt, glaciers tumbling to the ocean and whatever else. This is probably the reason that catastrophe movies (earthquakes, volcanoes, asteroids, ...) have such an appeal, we are entertained by the catastrophe itself.

On the other hand I am horrified by the implications, from severe weather, ocean acidification, species extinction, habitat destruction to a real threat to our civilisation (with non-negligible risk of collapse) to perhaps even a threat to our survival if everything goes really badly.

I do not see these two attitudes as contradictions, this is what it means to be human, we can live with paradoxes.

However, there is on huge difference with the movies: when the show ends we leave the theatre for the real word, with AGW in general and the Arctic in particular, this is the real world. (You can only leave by being a deluded politician denying the real world...)

So, back to the entertainment of a collapsing Arctic...
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on January 08, 2016, 04:00:58 PM
Unfortunately, trying to maintain a warm-and-fuzzy "let's not take it so seriously" attitude will do absolutely nothing to reduce the very real and catastrophic effects, the worst of which will be felt not by ocean-side dwelling First-worlders, but by 100's of millions of developing world people.  The world will not end, but from a human civilization perspective (especially those with less means to adapt) "doomsday" isn't so far from the truth. 

The problem is that such complacency leads to reduced action to avert more of the worst consequences.  We are already so, so far behind where we need to be . . . A strong sense of urgency is vital if our species hopes to survive in the future with anything close to the lifestyles most of us commenters are accustomed to.

i have not the slightest issue with this statement or better, i agree that dedication is needed, while i consider the fact that using strong negative wording will often lead to heavy opposing counter reactions. hence i believe that we should choose our words carefully to avoid being caught in errors that stick to the denialist's mind. my point was really more about psychology and seeking wise strategies than about denying any of the facts we deal with here. if i may say so and to make that point clear, i believe that many things will develop much faster and for some (i.e. banglasesh) be much worse than expected, but again these are not reasons a CEO of a company that deals with consumer products will listen to, hence the approach that will convince more people is worth more than the blunt approach that is assuring only those who are already convinced.
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on January 08, 2016, 05:13:56 PM

My attempt at humor at Cryosphere's data glitches have evolved into something more serious and probably off topic but will add one response.


I was on focus with the topic, at the same time that I was making a statement with my signature, that appears on every post: past, present and future. Of course, I had also fun with Cryosphere's data glitches, at the same time that I enphasized my signature statement.  ;) ;D

I will remove CT from my signature, because they are not forcasting with 2D data and I will move my ASI social movement to another topic or I will create a new one.

Have a good day!
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on January 09, 2016, 04:42:18 PM
After a "warm Arctic" at the end of 2015 and beginning of 2016, we start 2016 being the first on record. This could be for a short time frame, but from my point of view, having El Niño on 2016, we could be keeping from time to time this first lead, until the beginning of the melting season.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on January 11, 2016, 12:55:42 PM
(NOTE: I've updated the numbers to correct for an earlier error in the CT area data)


CT Area:
11,548,790 km2 (10 January [Day 0.0247])
Up 101,416 km2 (0.89%) from previous day.
Up 340,602 km2 (3.03%) over past seven days (daily average: 48,657 km2).
Up 411,153 km2 (3.69%) for January (daily average: 41,115 km2).
634,865 km2 below 2000s average for this date.
231,984 km2 below 2010s average for this date.
169,115 km2 below 2015 value for this date.
782,519 km2 below 2012 value for this date.
1st lowest January to-date average.
2nd lowest value for the date.
6 days this year (60% year-to-date) have recorded the lowest daily area.
4 days (40%) have recorded the second lowest.
0 days (0%) have recorded the third lowest.
10 days in total (100%) have been among the lowest three on record.

ADS-NIPR Extent:
Still awaiting an update; last available data are for 31 December.


Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on January 12, 2016, 06:44:16 PM
Update for the week to January 9th

The current 5 day mean is on 13,079,400km2 while the 1 day extent is at 13,192,000km2.

The daily anomaly (compared to 81-10) is at -1,016,760km2, an increase from -921,490km2 last week. The anomaly compared to the 07, 11 and 12 average is at -287,600km2, an increase from -206,470km2 last week. We're currently lowest on record, up from 2nd lowest last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FeSejuRc.png&hash=ad13a27d466242398a765bc99b7dfe4b)

The average daily change over the last 7 days was +40.2k/day, compared to the long term average of +53.8k/day, and the 07, 11 and 12 average of +51.8k/day.
The average long term change over the next week is +38.9k/day, with the 07, 11, and 12 average being +25.4k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F4fkX9KD.png&hash=ec8b0dbd42d5d58f595a441dcd250871)

The increase so far this January is the 2nd smallest on record. To achieve the smallest monthly gain, an increase of less than 27.1k/day is required, while the largest monthly gain requires an increase of at least 71.3k/day and an average gain requires an increase of 49.4k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fqucj5Tp.png&hash=704a35a43a6f0efff987a257631112af)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on January 13, 2016, 12:50:58 PM
ADS-NIPR Extent:
12,878,297 km2 (12 January)
Up 26,459 km2 (0.21%) from previous day.
Up 546,940 km2  (4.44%) over past seven days (daily average: 78,134 km2).
Up 605,222 km2  (4.95%) for January (daily average: 50,435 km2).
479,279 km2 below 2000s average for this date.
71,257 km2 below 2010s average for this date.
80,763 km2 above 2015 value for this date.
438,179 km2 below 2012 value for this date.
1st lowest January to-date average.
4th lowest value for the date.
6 days this year (50% year-to-date) have recorded the lowest daily extent.
0 days (0%) have recorded the second lowest.
0 days (0%) have recorded the third lowest.
6 days in total (50%) have been among the lowest three on record.


CT Area:
11,716,553 km2 (11 January [Day 0.0273])
Up 167,763 km2 (1.45%) from previous day.
Up 484,940 km2 (4.33%) over past seven days (daily average: 69,277 km2).
Up 578,916 km2 (5.2%) for January (daily average: 52,629 km2).
496,260 km2 below 2000s average for this date.
94,049 km2 below 2010s average for this date.
5,899 km2 above 2015 value for this date.
617,279 km2 below 2012 value for this date.
1st lowest January to-date average.
3rd lowest value for the date.
6 days this year (54.55% year-to-date) have recorded the lowest daily area.
4 days (36.36%) have recorded the second lowest.
1 days (9.09%) have recorded the third lowest.
11 days in total (100.%) have been among the lowest three on record.





Title: Re: 2016 sea ice area and extent data
Post by: Shared Humanity on January 13, 2016, 04:02:10 PM
BFTV and Jim.

I would like to just thank you for your informative posts here, straightforward data that allows me to easily track the Arctic. I visit this thread daily for the updates.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on January 16, 2016, 02:15:59 PM
ADS-NIPR Extent:
12,909,668 km2 (15 January)
Up 10,029 km2 (0.08%) from previous day.
Up 317,411 km2  (2.52%) over past seven days (daily average: 45,344 km2).
Up 636,593 km2  (5.2%) for January (daily average: 42,440 km2).
583,450 km2 below 2000s average for this date.
159,860 km2 below 2010s average for this date.
145,110 km2 below 2015 value for this date.
298,588 km2 below 2012 value for this date.
1st lowest January to-date average.
1st lowest value for the date.
8 days this year (53.33% year-to-date) have recorded the lowest daily extent.
1 day (6.67%) has recorded the second lowest.
1 day (6.67%) has recorded the third lowest.
10 days in total (66.67%) have been among the lowest three on record.


CT Area:
11,836,045 km2 (15 January [Day 0.0383])
Up 33,657 km2 (0.29%) from previous day.
Up 492,155 km2 (4.3%) over past seven days (daily average: 70,308 km2).
Up 698,408 km2 (6.27%) for January (daily average: 46,561 km2).
540,447 km2 below 2000s average for this date.
192,087 km2 below 2010s average for this date.
248,582 km2 below 2015 value for this date.
638,252 km2 below 2012 value for this date.
2nd lowest January to-date average.
3rd lowest value for the date.
6 days this year (40.0% year-to-date) have recorded the lowest daily area.
4 days (26.67%) have recorded the second lowest.
3 days (20.0%) have recorded the third lowest.
13 days in total (86.67%) have been among the lowest three on record.

BFTV and Jim.

I would like to just thank you for your informative posts here, straightforward data that allows me to easily track the Arctic. I visit this thread daily for the updates.

You are very welcome...
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on January 17, 2016, 09:26:44 AM
BFTV and Jim.

I would like to just thank you for your informative posts here, straightforward data that allows me to easily track the Arctic. I visit this thread daily for the updates.
I'll echo that.

Let me add a few thoughts.

Considering forecast weather and El Nino, I don't thing we've got much reason to expect the daily increases (40-45K/day) to significantly increase.

Considering the forecast and El Nino, I also don't think we've got much reason to expect the minimum to be any later this year than it was last year.  Even if it is, I don't expect it will be significantly higher.

To that end, the implication I see is, that we will only see the equivalent of about a months worth (being generous) of expansion of the ice this year.  That further implies a further increase of this year's refreeze of only about 1.25 million KM2.

Extrapolate as appropriate.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on January 17, 2016, 07:49:27 PM
Update for the week to January 16th

The current 5 day mean is on 13,501,200km2 while the 1 day extent is at 13,549,000km2.

The daily anomaly (compared to 81-10) is at -867,600km2, a decrease from -1,016,760km2 last week. The anomaly compared to the 07, 11 and 12 average is at -43,870km2, a decrease from -287,600km2 last week. We're currently 4th lowest on record, down from lowest last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F6c6CmVs.png&hash=7c8c662367ad71b9822bd561b0af27b5)

The average daily change over the last 7 days was +60.3k/day, compared to the long term average of +38.9k/day, and the 07, 11 and 12 average of +25.4k/day.
The average long term change over the next week is +39.9k/day, with the 07, 11, and 12 average being +36.5k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fc4qbTCQ.png&hash=9807342f72e7c29dbfa945c419de0299)

The increase so far this January is the 11th smallest on record. To achieve the smallest monthly gain, an increase of less than 11.7k/day is required, while the largest monthly gain requires an increase of at least 76.4k/day and an average gain requires an increase of 44.4k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FkzM0cND.png&hash=74760b396acd58f10930baea58769a1c)
Title: Re: 2016 sea ice area and extent data
Post by: Neven on January 17, 2016, 08:35:03 PM

Considering forecast weather and El Nino, I don't thing we've got much reason to expect the daily increases (40-45K/day) to significantly increase.

Considering the forecast and El Nino, I also don't think we've got much reason to expect the minimum to be any later this year than it was last year.  Even if it is, I don't expect it will be significantly higher.

To that end, the implication I see is, that we will only see the equivalent of about a months worth (being generous) of expansion of the ice this year.  That further implies a further increase of this year's refreeze of only about 1.25 million KM2.

Extrapolate as appropriate.

Last year the max was record low and early mainly because of a lack of ice in Bering and Okhotsk. This year so far there's slightly more sea ice there than last year, but this is easily compensated by low sea ice in the Barentsz Sea.

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-area-regional.png?attredirects=0)

If somehow there's rapid expansion on the Atlantic side of the Arctic, then the max won't be as low and early as last year, but that won't happen if this series of storms continues to push warm winds into the Arctic. Actually, I'm surprised to see how anomalously high temperatures still are, despite a very negative AO.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on January 23, 2016, 02:12:45 PM
ADS-NIPR Extent:
13,086,547 km2 (22 January)
Up 31,611 km2 (.24%) from previous day.
Up 176,879 km2  (1.37%) over past seven days (daily average: 25,268 km2).
Up 813,472 km2  (6.65%) for January (daily average: 36,976 km2).
685,150 km2 below 2000s average for this date.
189,722 km2 below 2010s average for this date.
242,710 km2 below 2015 value for this date.
273,697 km2 below 2012 value for this date.
1st lowest January to-date average.
3rd lowest value for the date.
8 days this year (36.36% year-to-date) have recorded the lowest daily extent.
3 days (13.64%) have recorded the second lowest.
6 days (27.27%) have recorded the third lowest.
17 days in total (77.27%) have been among the lowest three on record.


CT Area:
12,113,268 km2 (22 January [Day 0.0575])
Up 30,353 km2 (.25%) from previous day.
Up 277,223 km2 (2.33%) over past seven days (daily average: 39,603 km2).
Up 975,631 km2 (8.76%) for January (daily average: 44,347 km2).
618,584 km2 below 2000s average for this date.
130,043 km2 below 2010s average for this date.
340,957 km2 below 2015 value for this date.
103,833 km2 below 2012 value for this date.
2nd lowest January to-date average.
3rd lowest value for the date.
6 days this year (27.27% year-to-date) have recorded the lowest daily area.
8 days (36.36%) have recorded the second lowest.
6 days (27.27%) have recorded the third lowest.
20 days in total (90.91%) have been among the lowest three on record.

Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on January 24, 2016, 08:47:07 PM
Update for the week to January 23rd

The current 5 day mean is on 13,707,800km2 while the 1 day extent is at 13,695,000km2.

The daily anomaly (compared to 81-10) is at -940,350km2, an increase from -867,600km2 last week. The anomaly compared to the 07, 11 and 12 average is at -92,730km2, an increase from -43,870km2 last week. We're currently 3rd lowest on record, up from 4th lowest last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F9mvQhkf.png&hash=6bd9ff9e70caee7f0bc0114ae7ebb230)

The average daily change over the last 7 days was +29.5k/day, compared to the long term average of +39.9k/day, and the 07, 11 and 12 average of +36.5k/day.
The average long term change over the next week is +34.3k/day, with the 07, 11, and 12 average being +36.4k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F6Xgy87u.png&hash=a22e3d10dd9eef4b25ebfadae9fac7bd)

The increase so far this January is the 10th smallest on record. To achieve the smallest monthly gain, a loss of at least 0.5k/day is required, while the largest monthly gain requires an increase of at least 117.3k/day and an average gain requires an increase of 57.4k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fd4uPvBR.png&hash=966fc88dd0d77fee2e36a1903340c31e)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on January 31, 2016, 03:09:04 PM
ADS-NIPR Extent:
13,284,828 km2 (30 January)
Up 38,684 km2 (0.29%) from previous day.
Up 178,704 km2  (1.36%) over past seven days (daily average: 25,529 km2).
Up 1,011,753 km2  (8.27%) for January (daily average: 33,725 km2).
778,258 km2 below 2000s average for this date.
217,528 km2 below 2010s average for this date.
218,745 km2 below 2015 value for this date.
168,001 km2 below 2012 value for this date.
1st lowest January to-date average.
2nd lowest value for the date.
10 days this year (33.33% year-to-date) have recorded the lowest daily extent.
7 days (23.33%) have recorded the second lowest.
8 days (26.67%) have recorded the third lowest.
25 days in total (83.33%) have been among the lowest three on record.


CT Area:
12,212,527 km2 (30 January [Day 0.0795])
Up 33,503 km2 (0.28%) from previous day.
Up 57,597 km2 (0.47%) over past seven days (daily average: 8,228 km2).
Up 1,074,890 km2 (9.65%) for January (daily average: 35,830 km2).
767,945 km2 below 2000s average for this date.
250,069 km2 below 2010s average for this date.
481,558 km2 below 2015 value for this date.
204,186 km2 below 2012 value for this date.
2nd lowest January to-date average.
1st lowest value for the date.
9 days this year (30.0% year-to-date) have recorded the lowest daily area.
9 days (30.0%) have recorded the second lowest.
8 days (26.67%) have recorded the third lowest.
26 days in total (86.67%) have been among the lowest three on record.

Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on January 31, 2016, 06:44:08 PM
Update for the week to January 30th

The current 5 day mean is on 13,878,000km2 while the 1 day extent is at 13,907,000km2.

The daily anomaly (compared to 81-10) is at -1,009,980km2, an increase from -940,350km2 last week. The anomaly compared to the 07, 11 and 12 average is at -177,530km2, an increase from -92,730km2 last week. We're currently 2nd lowest on record, up from 3rd lowest last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F9Y9cniq.png&hash=ecb3e17c1edb8ca473f7a082f5a6221c)

The average daily change over the last 7 days was +24.4k/day, compared to the long term average of +34.3k/day, and the 07, 11 and 12 average of +36.4k/day.
The average long term change over the next week is +31.1k/day, with the 07, 11, and 12 average being +21.2k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fl9QVie1.png&hash=9ede6a3ae302f8c83cee35d7063ba4ac)

The increase so far this January is the 11th smallest on record. To achieve the smallest monthly gain, a loss of at least 202.1k/day is required, while the largest monthly gain requires an increase of at least 767.7k/day and an average gain requires an increase of 289.3k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fq8nYRbP.png&hash=ea9513652c135c99c752dee386c8cfb1)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on February 02, 2016, 01:10:02 PM
ADS-NIPR Extent:
13,308,481 km2 (01 February)
Down 8,974 km2 (-0.07%) from previous day.
Up 118,375 km2  (0.9%) over past seven days (daily average: 16,911 km2).
Down 8,974 km2  (-0.07%) for February (daily average: -8,974 km2).
803,339 km2 below 2000s average for this date.
236,613 km2 below 2010s average for this date.
262,887 km2 below 2015 value for this date.
147,022 km2 below 2012 value for this date.
Lowest February to-date average.
Lowest value for the date.
12 days this year (37.5% year-to-date) have recorded the lowest daily extent.
7 days (21.88%) have recorded the second lowest.
8 days (25.%) have recorded the third lowest.
27 days in total (84.38%) have been among the lowest three on record.


CT Area:
12,236,302 km2 (31 January [Day 0.0822])
Up 23,775 km2 (0.19%) from previous day.
Up 55,686 km2 (0.46%) over past seven days (daily average: 7,955 km2).
Up 1,098,665 km2 (9.86%) for January (daily average: 35,441 km2).
751,005 km2 below 2000s average for this date.
240,977 km2 below 2010s average for this date.
476,764 km2 below 2015 value for this date.
197,124 km2 below 2012 value for this date.
2nd lowest January average.
Lowest value for the date.
10 days this year (32.26% year-to-date) have recorded the lowest daily area.
9 days (29.03%) have recorded the second lowest.
8 days (25.81%) have recorded the third lowest.
27 days in total (87.1%) have been among the lowest three on record.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on February 06, 2016, 02:00:19 PM
ADS-NIPR Extent:
13,461,104 km2 (05 February)
Up 43,599 km2 (0.32%) from previous day.
Up 214,960 km2  (1.62%) over past seven days (daily average: 30,709 km2).
Up 143,649 km2  (1.17%) for February (daily average: 28,730 km2).
738,264 km2 below 2000s average for this date.
167,189 km2 below 2010s average for this date.
235,189 km2 below 2015 value for this date.
78,671 km2 below 2012 value for this date.
Lowest February to-date average.
Lowest value for the date.
16 days this year (44.44% year-to-date) have recorded the lowest daily extent.
7 days (19.44%) have recorded the second lowest.
8 days (22.22%) have recorded the third lowest.
31 days in total (86.11%) have been among the lowest three on record.


CT Area:
12,328,935 km2 (04 February [Day 0.0931])
Up 5,419 km2 (.04%) from previous day.
Up 181,593 km2 (1.49%) over past seven days (daily average: 25,942 km2).
Up 92,632 km2 (0.83%) for February (daily average: 23,158 km2).
760,905 km2 below 2000s average for this date.
320,973 km2 below 2010s average for this date.
537,913 km2 below 2015 value for this date.
216,497 km2 below 2012 value for this date.
Lowest February to-date average.
Lowest value for the date.
14 days this year (40.0% year-to-date) have recorded the lowest daily area.
9 days (25.71%) have recorded the second lowest.
8 days (22.86%) have recorded the third lowest.
31 days in total (88.57%) have been among the lowest three on record.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on February 07, 2016, 07:37:12 PM
Update for the week to Febraury 6th

The current 5 day mean is on 14,087,400km2 while the 1 day extent is at 14,196,000km2.

The daily anomaly (compared to 81-10) is at -1,018,150km2, an increase from -1,009,980km2 last week. The anomaly compared to the 07, 11 and 12 average is at -116,330km2, a decrease from -177,530km2 last week. We're currently lowest on record, up from 2nd lowest last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FN9nIoBd.png&hash=56dc30c084b9f434fc915350a8978e2b)

The average daily change over the last 7 days was +29.9k/day, compared to the long term average of +31.1k/day, and the 07, 11 and 12 average of +21.2k/day.
The average long term change over the next week is +19.3k/day, with the 07, 11, and 12 average being +28.7k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FPVdU2Qw.png&hash=6b2899a77e24ef222b43dbe17360bec1)

The increase so far this February is the 14th largest on record. To achieve the smallest monthly gain, a loss of at least 4.9k/day is required, while the largest monthly gain requires an increase of at least 29.9k/day and an average gain requires an increase of 16.1k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F9zSMLBr.png&hash=dc5046e54f9e6c45ad0e280eb1921e9f)

The increase this January was the 8th smallest on record, while the average extent was the 2nd smallest on record.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F4HJs6TE.png&hash=06cba6b33f34712141d5fca936bad5d1) (https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fxhrphwd.png&hash=a82574d4cdff91dd9f2b5ee4d812444a)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on February 13, 2016, 03:04:30 PM
ADS-NIPR Extent:
13,461,801 km2 (12 February)
Down 20,104 km2 (-.15%) from previous day.
Up 697 km2  (.01%) over past seven days (daily average: 100 km2).
Up 144,346 km2  (1.18%) for February (daily average: 12,029 km2).
919,460 km2 below 2000s average for this date.
343,242 km2 below 2010s average for this date.
427,512 km2 below 2015 value for this date.
452,363 km2 below 2012 value for this date.
Lowest February to-date average.
1st lowest value for the date.
22 days this year (51.16% year-to-date) have recorded the lowest daily extent.
8 days (18.6%) have recorded the second lowest.
8 days (18.6%) have recorded the third lowest.
38 days in total (88.37%) have been among the lowest three on record.


CT Area:
12,564,080 km2 (12 February [Day 0.1151])
Down 120,818 km2 (-0.95%) from previous day.
Up 257,522 km2 (2.09%) over past seven days (daily average: 36,789 km2).
Up 327,778 km2 (2.94%) for February (daily average: 27,315 km2).
793,522 km2 below 2000s average for this date.
208,102 km2 below 2010s average for this date.
325,344 km2 below 2015 value for this date.
67,719 km2 above 2012 value for this date.
Lowest February to-date average.
2nd lowest value for the date.
17 days this year (39.53% year-to-date) have recorded the lowest daily area.
10 days (23.26%) have recorded the second lowest.
8 days (18.6%) have recorded the third lowest.
35 days in total (81.4%) have been among the lowest three on record.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on February 14, 2016, 04:18:13 PM
Update for the week to February 13th

The current 5 day mean is on 14,175,600km2 while the 1 day extent is at 14,204,000km2.

The daily anomaly (compared to 81-10) is at -1,065,640km2, an increase from -1,018,150km2 last week. The anomaly compared to the 07, 11 and 12 average is at -229,330km2, an increase from -116,330km2 last week. We're currently lowest on record, the same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FwPmbUbI.png&hash=71aafd72b1ec9dc174f824cc0bbd6a31)

The average daily change over the last 7 days was +12.6k/day, compared to the long term average of +19.3k/day, and the 07, 11 and 12 average of +28.7k/day.
The average long term change over the next week is +18.9k/day, with the 07, 11, and 12 average being +26.0k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FXuBWX91.png&hash=e1263fcc0a829eaa48b18afe5fcc2ca5)

The increase so far this February is the 17th smallest on record. To achieve the smallest monthly gain, a loss of at least 12.5k/day is required, while the largest monthly gain requires an increase of at least 37.4k/day and an average gain requires an increase of 17.6k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F9O7vRWn.png&hash=f81e7c385e6f618ca08c4fb2ee0c1efb)
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on February 16, 2016, 10:48:52 PM
I am still waiting to see when the graph will go up, but as the days pass, I believe that we will have an end of freeze that will be the new lowest maximum record.  :o
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on February 17, 2016, 01:28:12 PM
ADS-NIPR Extent:
13,666,867 km2 (16 February)
Up 45,982 km2 (0.34%) from previous day.
Up 54,268 km2  (0.4%) over past seven days (daily average: 7,753 km2).
Up 349,412 km2  (2.86%) for February (daily average: 21,838 km2).
775,512 km2 below 2000s average for this date.
295,232 km2 below 2010s average for this date.
216,968 km2 below 2015 value for this date.
395,623 km2 below 2012 value for this date.
Lowest February to-date average.
Lowest value for the date.
26 days this year (55.32% year-to-date) have recorded the lowest daily extent.
8 days (17.02%) have recorded the second lowest.
8 days (17.02%) have recorded the third lowest.
42 days in total (89.36%) have been among the lowest three on record.


CT Area:
12,489,930 km2 (15 February [Day 0.1233])
Down 14,343 km2 (-0.11%) from previous day.
Down 61,378 km2 (-0.49%) over past seven days (daily average: -8,768 km2).
Up 253,628 km2 (2.28%) for February (daily average: 16,909 km2).
908,397 km2 below 2000s average for this date.
401,276 km2 below 2010s average for this date.
661,006 km2 below 2015 value for this date.
330,940 km2 below 2012 value for this date.
Lowest February to-date average.
Lowest value for the date.
20 days this year (43.48% year-to-date) have recorded the lowest daily area.
10 days (21.74%) have recorded the second lowest.
8 days (17.39%) have recorded the third lowest.
38 days in total (82.61%) have been among the lowest three on record.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on February 18, 2016, 05:19:40 PM
Just as a reminder: last year's CT area maxed out on February 17, though it was nearly 700k higher than the same day this year at 13,274,555 km2. One never knows what might happen, of course, but I don't foresee that much additional growth this year.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Hunt on February 18, 2016, 08:27:31 PM
It seems appropriate to cross post (http://forum.arctic-sea-ice.net/index.php/topic,1377.msg70254.html#msg70254) this information in here. Today NSIDC global sea ice extent and CT global sea ice area both reached their lowest ever levels since satellite records began:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fforum.arctic-sea-ice.net%2Findex.php%3Faction%3Ddlattach%3Btopic%3D1377.0%3Battach%3D25280%3Bimage&hash=a615057dfb6b19cb5db760bf83364ffb)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on February 20, 2016, 01:24:00 PM
ADS-NIPR Extent:
13,577,466 km2 (19 February)
Up 30,412 km2 (.22%) from previous day.
Up 115,665 km2  (.86%) over past seven days (daily average: 16,524 km2).
Up 260,011 km2  (2.13%) for February (daily average: 13,685 km2).
920,099 km2 below 2000s average for this date.
380,170 km2 below 2010s average for this date.
212,387 km2 below 2015 value for this date.
556,069 km2 below 2012 value for this date.
Lowest February to-date average.
Lowest value for the date.
29 days this year (58% year-to-date) have recorded the lowest daily extent.
8 days (16%) have recorded the second lowest.
8 days (16%) have recorded the third lowest.
45 days in total (90%) have been among the lowest three on record.


CT Area:
12,535,747 km2 (19 February [Day 0.1343])
Down 39,848 km2 (-0.32%) from previous day.
Down 28,334 km2 (-0.23%) over past seven days (daily average: -4,048 km2).
Up 299,444 km2 (2.69%) for February (daily average: 15,760 km2).
1,003,220 km2 below 2000s average for this date.
489,855 km2 below 2010s average for this date.
475,693 km2 below 2015 value for this date.
450,659 km2 below 2012 value for this date.
Lowest February to-date average.
Lowest value for the date.
24 days this year (48% year-to-date) have recorded the lowest daily area.
10 days (20%) have recorded the second lowest.
8 days (16%) have recorded the third lowest.
42 days in total (84%) have been among the lowest three on record.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on February 21, 2016, 05:55:23 PM
Update for the week to February 20th

The current 5 day mean is on 14,165,600km2 while the 1 day extent is at 14,179,000km2.

The daily anomaly (compared to 81-10) is at -1,207,740km2, an increase from -1,065,640km2 last week. The anomaly compared to the 07, 11 and 12 average is at -421,270km2, an increase from -229,330km2 last week. We're currently lowest on record, the same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FBnPKJwN.png&hash=c9a0c09e67c570ef9b5095e9604b1690)

The average daily change over the last 7 days was -1.4k/day, compared to the long term average of +18.9k/day, and the 07, 11 and 12 average of +26.0k/day.
The average long term change over the next week is +15.8k/day, with the 07, 11, and 12 average being +12.7k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fi71ZTMo.png&hash=499d86329fb84c1d89d16badfb31dcdc)

The increase so far this February is the 8th smallest on record. To achieve the smallest monthly gain, a loss of at least 20.9k/day is required, while the largest monthly gain requires an increase of at least 67.7k/day and an average gain requires an increase of 32.5k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FRXXjXLM.png&hash=d2064118b4f2a0de277c9afbbe6f1d56)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on February 23, 2016, 02:52:15 PM
ADS-NIPR Extent:
13,593,241 km2 (22 February)
Up 6,256 km2 (0.05%) from previous day.
Down 27,644 km2  (-0.2%) over past seven days (daily average: -3,949 km2).
Up 275,786 km2  (2.25%) for February (daily average: 12,536 km2).
949,764 km2 below 2000s average for this date.
405,065 km2 below 2010s average for this date.
307,444 km2 below 2015 value for this date.
486,113 km2 below 2012 value for this date.
Lowest February to-date average.
Lowest value for the date.
32 days this year (60.38% year-to-date) have recorded the lowest daily extent.
8 days (15.09%) have recorded the second lowest.
8 days (15.09%) have recorded the third lowest.
48 days in total (90.57%) have been among the lowest three on record.


CT Area:
12,559,461 km2 (22 February [Day 0.1425])
Down 44,041 km2 (-0.35%) from previous day.
Up 69,530 km2 (0.56%) over past seven days (daily average: 9,933 km2).
Up 323,158 km2 (2.9%) for February (daily average: 14,689 km2).
959,421 km2 below 2000s average for this date.
501,180 km2 below 2010s average for this date.
467,064 km2 below 2015 value for this date.
451,026 km2 below 2012 value for this date.
Lowest February to-date average.
Lowest value for the date.
27 days this year (50.94% year-to-date) have recorded the lowest daily area.
10 days (18.87%) have recorded the second lowest.
8 days (15.09%) have recorded the third lowest.
45 days in total (84.91%) have been among the lowest three on record.



Title: Re: 2016 sea ice area and extent data
Post by: Pmt111500 on February 23, 2016, 04:23:05 PM
The useless piece of calculation today would be that extrapolating the CT SIA linearly to zero via two points, would mean that the 22nd of February, 2178 would be ice free in the Arctic (except Greenland). That is if I got that one correct on the phone calculator , deduction and memory. But almost a million lost in just c.12 years deserves some attention, esp. since it's pretty much mid-winter!

Aah, new ASIF User Classes!  :) Thank you Neven, I wasn't comfortable being a hero 8).
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on February 24, 2016, 02:33:29 PM
Yet another century drop for CT SIA. The numbers:


CT Area:
12,446,272 km2 (23 February [Day 0.1453])
Down 113,189 km2 (-0.9%) from previous day.
Down 79,106 km2 (-0.63%) over past seven days (daily average: -11,301 km2).
Up 209,970 km2 (1.89%) for February (daily average: 9,129 km2).
1,074,786 km2 below 2000s average for this date.
616,101 km2 below 2010s average for this date.
637,179 km2 below 2015 value for this date.
575,501 km2 below 2012 value for this date.

That's a 12-day decrease of 239k from the 2016 maximum-to-date of 12.685 million on February 11. The average SIA increase from today through the annual max over the past ten years has been 374k, so I wouldn't call the max just yet. (It's not even out of the question that ice could grow enough to crack the 13 million mark.) But after another couple of strong decreases over the next week or so, I just might. At any rate, area has no more than five weeks at best to push through the ceiling; after that, the downhill race gets underway in earnest...

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FUU4qRer.png&hash=f0911e3135cc03f31dc7adf563e92857)
Title: Re: 2016 sea ice area and extent data
Post by: Tor Bejnar on February 24, 2016, 02:58:49 PM
I note that about 3 years' data in the projection suggest a new record low NH Autumn sea ice minimum. (A few days ago only 2012 ice loss amounts projected a new record.) If the record low for the date continues for a month or so, it will begin to suggest a likely (not just possible) new Autumn minimum.  The details are "all" weather, but Jim Pettit's graph shows climate's hand in this process.  When (if) all the yellow (2010-15) lines cross the 'new minimum' threshold, then the foreboding will really start!
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on February 24, 2016, 08:47:55 PM
Difficult to beleive that it is really happening...
Title: Re: 2016 sea ice area and extent data
Post by: DavidR on February 24, 2016, 08:49:55 PM
Yet another century drop for CT SIA.

Over the past 10  years the largest increase in CT area from this date is 687K in 2012. For the first time this year, the largest increase from  this date since 2006 is not large enough to prevent a new record low.  No other increase in those years will  take the area above 13M and 3 of the increases will not take us above the current high  for this year.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on February 27, 2016, 01:58:23 PM
ADS-NIPR Extent:
13,867,055 km2 (26 February)
Down 10,139 km2 (-0.07%) from previous day.
Up 289,589 km2  (2.13%) over past seven days (daily average: 41,370 km2).
Up 549,600 km2  (4.49%) for February (daily average: 21,138 km2).
731,380 km2 below 2000s average for this date.
229,226 km2 below 2010s average for this date.
61,383 km2 below 2015 value for this date.
439,112 km2 below 2012 value for this date.
Lowest February to-date average.
2nd lowest value for the date.
34 days this year (59.65% year-to-date) have recorded the lowest daily extent.
10 days (17.54%) have recorded the second lowest.
8 days (14.04%) have recorded the third lowest.
52 days in total (91.23%) have been among the lowest three on record.


CT Area:
12,754,528 km2 (26 February [Day 0.1534])
Up 136,190 km2 (1.08%) from previous day.
Up 218,781 km2 (1.74%) over past seven days (daily average: 31,254 km2).
Up 518,226 km2 (4.65%) for February (daily average: 19,932 km2).
812,567 km2 below 2000s average for this date.
378,804 km2 below 2010s average for this date.
298,207 km2 below 2015 value for this date.
391,456 km2 below 2012 value for this date.
Lowest February to-date average.
2nd lowest value for the date.
30 days this year (52.63% year-to-date) have recorded the lowest daily area.
11 days (19.3%) have recorded the second lowest.
8 days (14.04%) have recorded the third lowest.
49 days in total (85.96%) have been among the lowest three on record.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on February 28, 2016, 08:44:32 PM
Update for the week to February 27th

The current 5 day mean is on 14,336,000km2 while the 1 day extent is at 14,428,000km2.

The daily anomaly (compared to 81-10) is at -1,148,070km2, a decrease from -1,207,740km2 last week. The anomaly compared to the 07, 11 and 12 average is at -339,730km2, a decrease from -421,270km2 last week. We're currently lowest on record, the same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FzUXHF1g.png&hash=0c5d4d8fe1ca16710d9dd72e55308752)

The average daily change over the last 7 days was +24.4k/day, compared to the long term average of +15.8k/day, and the 07, 11 and 12 average of +12.7k/day.
The average long term change over the next week is +2.2k/day, with the 07, 11, and 12 average being +19.9k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FPZJEdy2.png&hash=eceecd7cf450d0852fecb63723b1b08b)

The increase so far this February is the 11th smallest on record. To achieve the smallest monthly gain, a loss of at least 179.1k/day is required, while the largest monthly gain requires an increase of at least 219.2k/day and an average gain requires an increase of 61.0k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F6AND8JP.png&hash=1f36c8d00a32606692b2df209d749031)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on March 05, 2016, 12:58:45 PM
ADS-NIPR Extent:
13,789,796 km2 (04 March)
Down 34,661 km2 (-0.25%) from previous day.
Down 87,398 km2  (-0.63%) over past seven days (daily average: -12,485 km2).
Down 152,711 km2  (-1.25%) for March (daily average: -38,178 km2).
879,656 km2 below 2000s average for this date.
373,808 km2 below 2010s average for this date.
100,799 km2 above 2015 value for this date.
909,921 km2 below 2012 value for this date.
2nd lowest March to-date average.
2nd lowest value for the date.
34 days this year (53.97% year-to-date) have recorded the lowest daily extent.
13 days (20.63%) have recorded the second lowest.
9 days (14.29%) have recorded the third lowest.
56 days in total (88.89%) have been among the lowest three on record.


CT Area:
12,765,717 km2 (02 March [Day 0.1644])
Up 25,252 km2 (0.2%) from previous day.
Up 319,445 km2 (2.56%) over past seven days (daily average: 45,635 km2).
Down 10,110 km2 (-0.09%) for March (daily average: -5,055 km2).
893,046 km2 below 2000s average for this date.
418,373 km2 below 2010s average for this date.
371,306 km2 below 2015 value for this date.
544,880 km2 below 2012 value for this date.
1st lowest March to-date average.
1st lowest value for the date.
32 days this year (51.61% year-to-date) have recorded the lowest daily area.
14 days (22.58%) have recorded the second lowest.
8 days (12.9%) have recorded the third lowest.
54 days in total (87.1%) have been among the lowest three on record.



Title: Re: 2016 sea ice area and extent data
Post by: jdallen on March 05, 2016, 06:57:48 PM
<snippage>
893,046 km2 below 2000s average for this date.
418,373 km2 below 2010s average for this date.
371,306 km2 below 2015 value for this date.
544,880 km2 below 2012 value for this date.
1st lowest March to-date average.
1st lowest value for the date.
<more snippage>
This, more than the low extent, really, really worries me.
Title: Re: 2016 sea ice area and extent data
Post by: Tor Bejnar on March 05, 2016, 07:27:52 PM
<snippage>
893,046 km2 below 2000s average for this date.
418,373 km2 below 2010s average for this date.
371,306 km2 below 2015 value for this date.
544,880 km2 below 2012 value for this date.
1st lowest March to-date average.
1st lowest value for the date.
<more snippage>
This, more than the low extent, really, really worries me.
As sea ice area (SIA) measurements are not affected by melt ponds until sometime in May, it is probable that more sunlight has hit open water (mostly glancing off, unless the water is choppy) in the far north in recent weeks than has happened in hundreds or thousands of years.  Although not a lot of solar energy is getting into the ocean at this time, I expect it is more than in recent years.  A physicist among us could probably give us some numbers to consider; we would then know how significant this year's situation is.
Title: Re: 2016 sea ice area and extent data
Post by: Andreas T on March 05, 2016, 08:26:47 PM
At this time of the year open water looses more heat than it receives. It is warmer than the ice surface and it evaporates which the ice surface does much less, so it looses more heat than an ice surface.
The important question though is what does the opening now mean for the state of the ice when solar inputs are much stronger in the summer. What does it say about the state of the ice and its movements?
Another side to the evaporation which can be seen as fog in satellite images is that it decreases heat loss from ice under fog relative to ice under clear sky. It also inceases heat loss from the top of the fog layer relative to a clear atmosphere.

Not a straight answer, I am sorry, how these effects balance out I don't know.
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on March 05, 2016, 09:37:23 PM
At this time of the year open water looses more heat than it receives. It is warmer than the ice surface and it evaporates which the ice surface does much less, so it looses more heat than an ice surface.
The important question though is what does the opening now mean for the state of the ice when solar inputs are much stronger in the summer. What does it say about the state of the ice and its movements?
Another side to the evaporation which can be seen as fog in satellite images is that it decreases heat loss from ice under fog relative to ice under clear sky. It also inceases heat loss from the top of the fog layer relative to a clear atmosphere.

Not a straight answer, I am sorry, how these effects balance out I don't know.
The key element in my mind is not the current heat loss out of open water, which will be higher.

It's the water which will most likely *remain* open as we start seeing the rapid ramp up of insolation.  Those open areas will have a quarter of the albedo of snow covered ice, and 370,000 KM2 of lower albedo will recapture energy lost very quickly.

In two weeks, areas at 80N will start getting 2 kilowatt hours per square meter a day of insolation.  That should be about the time energy input balances out the daily radiative loss.  By the time we get to April 1st, that available energy doubles.  By the time we get to May 1st, we're at 14KWH/Day/M2 of incident radiation hitting the sea surface.  It only gets worse.

That's a massive change in the Arctic's spring energy budget, when we haven't even started to think about melt ponds. A lot of that extra open water is on or near the Atlantic side of the basin, deep in the arctic, so that energy will be getting embedded in the middle of a key part of the basin needed for preserving the pack.

It is very worrisome.

[edit:  one of the key factors I'm contemplating here is the distribution of the ice.  It is far different from 2015 and 2012, both of which had much more ice, but more to the point, that ice was not as asymmetrically distributed.  In 2016, right now, there is far more open water, at higher latitude, than we've seen in the modern record.  Due to the character of how incident insolation is greater at high latitudes than at lower after the equinox translates to that open water at high latitude picking up far more energy.  I conclude open water at 80N and above is far more dangerous than it is in the Bering, Beaufort, or other peripheral seas at lower latitude.]
Title: Re: 2016 sea ice area and extent data
Post by: DavidR on March 05, 2016, 09:54:06 PM
<snippage>
893,046 km2 below 2000s average for this date.
418,373 km2 below 2010s average for this date.
371,306 km2 below 2015 value for this date.
544,880 km2 below 2012 value for this date.
1st lowest March to-date average.
1st lowest value for the date.
<more snippage>
This, more than the low extent, really, really worries me.

Last year at this stage only 6 days had been in the lowest 3 on record. This year it  is 54. That says an awful lot  about the state of the ice and the amount of open water that  must  be around to start receiving insolation.
Title: Re: 2016 sea ice area and extent data
Post by: Andreas T on March 05, 2016, 11:49:15 PM
.....
In two weeks, areas at 80N will start getting 2 kilowatt hours per square meter a day of insolation.  That should be about the time energy input balances out the daily radiative loss.  By the time we get to April 1st, that available energy doubles.  By the time we get to May 1st, we're at 14KWH/Day/M2 of incident radiation hitting the sea surface.  It only gets worse.
.....
Are these values top of the atmosphere irradiances?
I found some measured surface values for 75 -80 deg north here:
http://onlinelibrary.wiley.com/doi/10.1029/2006JC003558/full (http://onlinelibrary.wiley.com/doi/10.1029/2006JC003558/full)
to get kWh from MJ divide by 3.6 i.e 30MJ is 8.3kWh/ day /m2 max in June
Title: Re: 2016 sea ice area and extent data
Post by: Andreas T on March 06, 2016, 12:10:07 AM
from the paper cited abovehttps://www.researchgate.net/profile/Marcel_Nicolaus/publication/234833783_Changes_in_Arctic_sea_ice_result_in_increasing_light_transmittance_and_absorption/links/0fcfd5112abcc37990000000.pdf (https://www.researchgate.net/profile/Marcel_Nicolaus/publication/234833783_Changes_in_Arctic_sea_ice_result_in_increasing_light_transmittance_and_absorption/links/0fcfd5112abcc37990000000.pdf) (i.e. written in 2011) :
Quote
learly, short-wave radiative fluxes into the ocean will
increase in the future due to sea ice retreat, resulting in more
open water. Our results show that there will also be a signifi-
cant increase of fluxes through the (remaining) sea ice due to
the shift to more FYI. To the extent that the FYI measurements
described here are representative for todays summer condi-
tions, FYI transmits almost three times as much light as MYI,
which is expected to have less and less coverage in the future.
Averaging over the entire Arctic with a 50/50 distribution of
FYI and MYI in 2011 (Figure S5), todays transmittanceof
solar irradiance over the entire Arctic sea ice is 0.08. Assuming
similar fractions of pond coverage and transmittance ratios
of FYI and MYI in the future, solar heat input will increase by
about 50% when the point is reached where only small frac-
tions (e.g. 10%) of the Arctic are covered with MYI during
summer
Quote
However, a potential increase of
absolute fluxes through sea ice into the upper ocean also
depends on the evolution of solar surface irradiance, which is
strongly affected by clouds
Quote
For all further studies of season-
ality more (similar) large-scale observations are necessary to
allow the generation of a transmittance seasonality for dif-
ferent ice types [Nicolaus et al, 2010b; Perovich et al. 2011].
 Therefore, additional observations are suggested as
future work. This would be most beneficial between May and
July when fluxes are highly relevant for sea-ice mass balance
and primary productivity. At that time of year, the distribu-
tion of snow is particularly important in determining light
penetration and control its spatial variability

This is also interesting
Quote
In that
respect, strongly deformed FYI is also much more similar to
MYI than level FYI. Hence, changes in sea-ice dynamics
could also impact light transmittance of future sea ice beyond
the here presented aspects.
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on March 06, 2016, 01:50:20 AM
.....
In two weeks, areas at 80N will start getting 2 kilowatt hours per square meter a day of insolation.  That should be about the time energy input balances out the daily radiative loss.  By the time we get to April 1st, that available energy doubles.  By the time we get to May 1st, we're at 14KWH/Day/M2 of incident radiation hitting the sea surface.  It only gets worse.
.....
Are these values top of the atmosphere irradiances?
I found some measured surface values for 75 -80 deg north here:
http://onlinelibrary.wiley.com/doi/10.1029/2006JC003558/full (http://onlinelibrary.wiley.com/doi/10.1029/2006JC003558/full)
to get kWh from MJ divide by 3.6 i.e 30MJ is 8.3kWh/ day /m2 max in June

Raw, it's about 1600W/M2 oblique at the top of the atmosphere.  By the time you get down to sea level, it's about 330.  You factor in the angle (about 43 degrees at 80N on Jun 21st at mid day) and I see that as around 12KWH/M2/Day.  Caveat: optical calculations are not my strong suit, so if anyone can show us better numbers, I'm fine with it.

Now, even if I'm off significantly, we can look at the factor for Albedo.  Ice with snow has an Albedo of about .85 - most of the energy is getting tossed back out.

Albedo of sea water at worst is going to be about 0.2.   So at worst, the areas exposed to sunlight can conservatively pick up 5 times the energy they would if they were still covered with sea ice.  That's a massive increase in energy input into the areas affected, and doesn't improve particularly if there's cloud cover.

I'm hard pressed to see how that could not have a significant effect conditioning the pack at the start of the melt season.
Title: Re: 2016 sea ice area and extent data
Post by: Tor Bejnar on March 06, 2016, 02:03:08 AM
Thanks, jdallen and others for this discussion.
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on March 06, 2016, 02:04:26 AM
Let me make something else clear here.

Even with the massive inputs of energy, I'm not suggesting we will see sudden massive melting before the typical start of the melt season.

What I'm suggesting is, the extra energy will give the melt season a running start.  What I *think* that will translate into is, 1-2 weeks of additional melting on either end of the season. 

What the heat will be doing is boosting the net energy input into the system by something like 2-3%.  While that may not seem like a lot, it will add up quickly.

I think where that heat goes will be key to how the melt season plays out.
Title: Re: 2016 sea ice area and extent data
Post by: Tealight on March 06, 2016, 04:20:07 AM
.....
In two weeks, areas at 80N will start getting 2 kilowatt hours per square meter a day of insolation.  That should be about the time energy input balances out the daily radiative loss.  By the time we get to April 1st, that available energy doubles.  By the time we get to May 1st, we're at 14KWH/Day/M2 of incident radiation hitting the sea surface.  It only gets worse.
.....
Are these values top of the atmosphere irradiances?
I found some measured surface values for 75 -80 deg north here:
http://onlinelibrary.wiley.com/doi/10.1029/2006JC003558/full (http://onlinelibrary.wiley.com/doi/10.1029/2006JC003558/full)
to get kWh from MJ divide by 3.6 i.e 30MJ is 8.3kWh/ day /m2 max in June

Raw, it's about 1600W/M2 oblique at the top of the atmosphere.  By the time you get down to sea level, it's about 330.  You factor in the angle (about 43 degrees at 80N on Jun 21st at mid day) and I see that as around 12KWH/M2/Day.  Caveat: optical calculations are not my strong suit, so if anyone can show us better numbers, I'm fine with it.

On what Planet do you live?  ;D

On 21st June the max angle at 80N is only 33.4 degrees. The earth is tilted by 23.4 degrees and for 80N you just add another 10 degrees to that.
The solar constant on top of the atmosphere is on average 1365W/m2, but in June/July it is only 1321W/m2, because Earth is close to aphelion.

I think what most people don't realise is how much solar radiation thin clouds/haze or can filter out, when the sun is at a very low angle.
Most of us live in the temperate region 40-60N, where even in winter the solar angle can be higher than in the Arctic during summer.

I once created a chart which shows the distance a "light beam" has to travel through a cloud for various angles. The actual distance is of course even higher because the light gets constantly absorbed and re emitted.

For comparison at 50N on 21st June the max solar angle is 63.3 degrees.

Title: Re: 2016 sea ice area and extent data
Post by: jdallen on March 06, 2016, 08:32:08 AM
.....
In two weeks, areas at 80N will start getting 2 kilowatt hours per square meter a day of insolation.  That should be about the time energy input balances out the daily radiative loss.  By the time we get to April 1st, that available energy doubles.  By the time we get to May 1st, we're at 14KWH/Day/M2 of incident radiation hitting the sea surface.  It only gets worse.
.....
Are these values top of the atmosphere irradiances?
I found some measured surface values for 75 -80 deg north here:
http://onlinelibrary.wiley.com/doi/10.1029/2006JC003558/full (http://onlinelibrary.wiley.com/doi/10.1029/2006JC003558/full)
to get kWh from MJ divide by 3.6 i.e 30MJ is 8.3kWh/ day /m2 max in June

Raw, it's about 1600W/M2 oblique at the top of the atmosphere.  By the time you get down to sea level, it's about 330.  You factor in the angle (about 43 degrees at 80N on Jun 21st at mid day) and I see that as around 12KWH/M2/Day.  Caveat: optical calculations are not my strong suit, so if anyone can show us better numbers, I'm fine with it.

On what Planet do you live?  ;D

On 21st June the max angle at 80N is only 33.4 degrees. The earth is tilted by 23.4 degrees and for 80N you just add another 10 degrees to that.
The solar constant on top of the atmosphere is on average 1365W/m2, but in June/July it is only 1321W/m2, because Earth is close to aphelion.
*Brain* F*rt* - *90* degrees from the pole to the equator.  *90*... Nine Zero, not one hundred...   :P

Thank you for the numbers.

I do understand that cloud cover would significantly reduce the total heat reaching the surface.

Back again to my key point - Albedo.  Regardless of how much is getting through, a much larger fraction is going to get captured by open water.  Multiply that fraction by 370,000 KM2, it adds up to a large amount of heat.
Title: Re: 2016 sea ice area and extent data
Post by: Andreas T on March 06, 2016, 09:21:29 AM
.....

I once created a chart which shows the distance a "light beam" has to travel through a cloud for various angles. The actual distance is of course even higher because the light gets constantly absorbed and re emitted.
....
You seem to confuse scattering with absorption. Sunlight is "filtered" by the cloud droplets by scattering the incoming energy into all directions (some more than others) including downwards. That downwards scattered light is scattered again as it encounters more droplets depending on the thickness and density of the cloud.
Diffuse light from clouds is part of the energy input at the surface, but of course that is less than would be received by direct sunlight.
Title: Re: 2016 sea ice area and extent data
Post by: LRC1962 on March 06, 2016, 01:23:52 PM
Personally IMO how much radiation from sunlight the Arctic will receive this year is totally ignoring the changes that seem to be happening. Look at this chart:
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fcires1.colorado.edu%2F%7Easlater%2FARCTIC_TAIR%2FIMG%2Farctic_t2m_dfa_2016.gif&hash=1c5ce41ff39e4229cf35941ef29167a2)

That is all the result of a lot of heat being pumped into the Arctic via storms. I think the main culprit is the cold Blob + superheated Golf Stream setting up dipoles that spin big storms into the heart of the Atlantic side of the Arctic. Since the experts are tending to believe that with the changes in the NA, they are going to be permanent fixtures, I do not think it is going out on a limb in saying that from now on, big storms spinning into the Arctic will become a year round occurrence. If that becomes the case those storms will be the biggest decider of melt and not the sun.
Title: Re: 2016 sea ice area and extent data
Post by: Tealight on March 06, 2016, 04:12:00 PM
You seem to confuse scattering with absorption. Sunlight is "filtered" by the cloud droplets by scattering the incoming energy into all directions (some more than others) including downwards. That downwards scattered light is scattered again as it encounters more droplets depending on the thickness and density of the cloud.
Diffuse light from clouds is part of the energy input at the surface, but of course that is less than would be received by direct sunlight.

I know that most of the light is scattered and not absorbed, but it still makes a difference if it is scattered 100 or 200 times.
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on March 06, 2016, 10:55:29 PM
Personally IMO how much radiation from sunlight the Arctic will receive this year is totally ignoring the changes that seem to be happening. Look at this chart:
<snippage>
That is all the result of a lot of heat being pumped into the Arctic via storms. I think the main culprit is the cold Blob + superheated Golf Stream setting up dipoles that spin big storms into the heart of the Atlantic side of the Arctic. Since the experts are tending to believe that with the changes in the NA, they are going to be permanent fixtures, I do not think it is going out on a limb in saying that from now on, big storms spinning into the Arctic will become a year round occurrence. If that becomes the case those storms will be the biggest decider of melt and not the sun.
Completely agree, LRC.  The point I've made doesn't have to do with how the Arctic was warm this winter.  Rather, I'm focusing in on how early, lower extent will increase the amount of energy captured early in the melt season coming up.  Compared to previous seasons, 2016 is...

2015    2.8% lower
2012    4.1% lower
2010s   3.1% lower

The extent this year, at this time is very similar to 2012, save for somewhat more extent being open in the Barents, and a *lot* more extent open in the Bering.

http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=03&fd=04&fy=2012&sm=03&sd=04&sy=2016 (http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=03&fd=04&fy=2012&sm=03&sd=04&sy=2016)

2016 has somewhat more extent in the Bering and considerably more in the Okhotsk than 2015, and significantly less on the Atlantic side.

http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=03&fd=05&fy=2015&sm=03&sd=04&sy=2016 (http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=03&fd=05&fy=2015&sm=03&sd=04&sy=2016)

The effect right now will be to dump more heat out of the water into the atmosphere - which will contribute to higher 80N temperatures and constrain ice thickening elsewhere.

The effect after the equinox will be to capture 80% more insolation over that area which in previous years would have been radiated into space, on the "wrong" side of the summer solstice. Add particularly, this heat is getting dumped into areas at high latitude which normally don't see that much heat until well into the melt season.

It's only 3% more relative to the total ice cover in the arctic, but it's like attaching a small weight to a spinning disk; it destabilizes the balance and sets off (mostly) unpredictable oscillations in the system.

Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on March 07, 2016, 12:29:32 PM
Update for the week to March 5th

The current 5 day mean is on 14,392,200km2 while the 1 day extent is at 14,381,000km2.

The daily anomaly (compared to 81-10) is at -1,107,010km2, a decrease from -1,148,070km2 last week. The anomaly compared to the 07, 11 and 12 average is at -423,070km2, an increase from -339,730km2 last week. We're currently lowest on record, the same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FnS7VZ2r.png&hash=c3877cb660233692b819790413400c24)

The average daily change over the last 7 days was +8.1k/day, compared to the long term average of +2.2k/day, and the 07, 11 and 12 average of +19.9k/day.
The average long term change over the next week is +0.8k/day, with the 07, 11, and 12 average being +4.3k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Famojx4B.png&hash=459a43ea429f3a808d7da430522ed086)

The extent change so far this March is the 8th most negative on record. To achieve the smallest monthly gain, a loss of at least 23.7k/day is required, while the largest monthly gain requires an increase of at least 18.8k/day and an average gain requires a loss of 5.0k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FhVgouQu.png&hash=7b2df5453096a618d766140a96782379)

The extent increase in February was the 11th smallest on record, while the average extent was the smallest on record and first to average below 14.5 million km2

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Ffm5SbFi.png&hash=99835150369982a4beaff04e5c680231)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FoGGSfnA.png&hash=3e3661b26b6ae158384e27e7c4c64fe3)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on March 08, 2016, 01:01:10 PM
ADS-NIPR Extent:
13,858,745 km2 (07 March)
Up 61,752 km2 (0.45%) from previous day.
Down 83,762 km2  (-0.6%) over past seven days (daily average: -11,966 km2).
Down 83,762 km2  (-0.68%) for March (daily average: -11,966 km2).
811,603 km2 below 2000s average for this date.
357,852 km2 below 2010s average for this date.
199,329 km2 above 2015 value for this date.
850,341 km2 below 2012 value for this date.
2nd lowest March to-date average.
2nd lowest value for the date.
34 days this year (51.52% year-to-date) have recorded the lowest daily extent.
16 days (24.24%) have recorded the second lowest.
9 days (13.64%) have recorded the third lowest.
59 days in total (89.39%) have been among the lowest three on record.


CT Area:
12,724,465 km2 (06 March [Day 0.1753])
Down 21,882 km2 (-0.17%) from previous day.
Down 118,621 km2 (-0.93%) over past seven days (daily average: -16,946 km2).
Down 51,361 km2 (-0.46%) for March (daily average: -8,560 km2).
989,901 km2 below 2000s average for this date.
508,056 km2 below 2010s average for this date.
304,130 km2 below 2015 value for this date.
956,007 km2 below 2012 value for this date.
Lowest March to-date average.
Lowest value for the date.
35 days this year (53.85% year-to-date) have recorded the lowest daily area.
14 days (21.54%) have recorded the second lowest.
8 days (12.31%) have recorded the third lowest.
57 days in total (87.69%) have been among the lowest three on record.

Stat of the day: CT SIA is currently 956,007 km2 below the 2012 value for this date. That's a difference in area roughly the size of the US states of Texas and Oregon combined.



Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on March 09, 2016, 12:39:07 PM
ADS-NIPR Extent:
13,921,066 km2 (08 March)
Up 62,321 km2 (.45%) from previous day.
Down 3,128 km2  (-.02%) over past seven days (daily average: -447 km2).
Down 21,441 km2  (-.18%) for March (daily average: -2,680 km2).
747,582 km2 below 2000s average for this date.
284,109 km2 below 2010s average for this date.
271,197 km2 above 2015 value for this date.
685,491 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 08 March) average.
2nd lowest March to-date average.
2nd lowest value for the date.
34 days this year (50.75% year-to-date) have recorded the lowest daily extent.
17 days (25.37%) have recorded the second lowest.
9 days (13.43%) have recorded the third lowest.
60 days in total (89.55%) have been among the lowest three on record.


CT Area:
12,723,368 km2 (07 March [Day 0.1781])
Down 1,098 km2 (-0.01%) from previous day.
Down 52,459 km2 (-0.41%) over past seven days (daily average: -7,494 km2).
Down 52,459 km2 (-0.47%) for March (daily average: -7,494 km2).
995,370 km2 below 2000s average for this date.
541,114 km2 below 2010s average for this date.
284,673 km2 below 2015 value for this date.
941,751 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.1781) average.
Lowest March to-date average.
Lowest value for the date.
36 days this year (54.55% year-to-date) have recorded the lowest daily area.
14 days (21.21%) have recorded the second lowest.
8 days (12.12%) have recorded the third lowest.
58 days in total (87.88%) have been among the lowest three on record.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on March 11, 2016, 12:23:43 PM
ADS-NIPR Extent:
13,855,406 km2 (10 March)
Down 43,077 km2 (-.31%) from previous day.
Up 30,949 km2  (.22%) over past seven days (daily average: 4,421 km2).
Down 87,101 km2  (-.71%) for March (daily average: -8,710 km2).
806,501 km2 below 2000s average for this date.
306,231 km2 below 2010s average for this date.
231,638 km2 above 2015 value for this date.
655,016 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 10 March) average.
2nd lowest March to-date average.
2nd lowest value for the date.
34 days this year (49.28% year-to-date) have recorded the lowest daily extent.
19 days (27.54%) have recorded the second lowest.
9 days (13.04%) have recorded the third lowest.
62 days in total (89.86%) have been among the lowest three on record.


CT Area:
12,754,865 km2 (09 March [Day 0.1836])
Up 24,532 km2 (.19%) from previous day.
Down 10,852 km2 (-.09%) over past seven days (daily average: -1,550 km2).
Down 20,962 km2 (-.19%) for March (daily average: -2,329 km2).
958,378 km2 below 2000s average for this date.
506,414 km2 below 2010s average for this date.
213,137 km2 below 2015 value for this date.
854,555 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.1836) average.
Lowest March to-date average.
Lowest value for the date.
38 days this year (55.88% year-to-date) have recorded the lowest daily area.
14 days (20.59%) have recorded the second lowest.
8 days (11.76%) have recorded the third lowest.
60 days in total (88.24%) have been among the lowest three on record.

Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on March 14, 2016, 10:45:16 AM
Update for the week to March 12th

The current 5 day mean is on 14,373,200km2 while the 1 day extent is at 14,388,000km2.

The daily anomaly (compared to 81-10) is at -1,132,060km2, an increase from -1,107,010km2 last week. The anomaly compared to the 07, 11 and 12 average is at -472,330km2, an increase from -423,070km2 last week. We're currently 2nd lowest on record, down from lowest last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FL58M6Lf.png&hash=ee7e0c1f7b0b985c072264b731aec5af)

The average daily change over the last 7 days was -2.7k/day, compared to the long term average of +0.8k/day, and the 07, 11 and 12 average of +4.3k/day.
The average long term change over the next week is -9.8k/day, with the 07, 11, and 12 average being -5.5k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F79YVnEd.png&hash=bb7907441872574d8c166e772534fc06)

The extent change so far this March is the 11th most negative on record. To achieve the largest monthly loss, a drop of at least 31.4k/day is required, while the largest monthly gain requires an increase of at least 26.8k/day and an average gain requires a loss of 5.8k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F8OcUzhu.png&hash=4b47f875f6e91f792183f45a3ef64b9f)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on March 14, 2016, 11:35:57 AM
ADS-NIPR Extent:
13,872,861 km2 (13 March)
Down 27,697 km2 (-.2%) from previous day.
Up 75,868 km2  (.55%) over past seven days (daily average: 10,838 km2).
Down 69,646 km2  (-.57%) for March (daily average: -5,357 km2).
744,787 km2 below 2000s average for this date.
337,592 km2 below 2010s average for this date.
186,445 km2 above 2015 value for this date.
705,035 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 13 March) average.
2nd lowest March to-date average.
2nd lowest value for the date.
34 days this year (47.22% year-to-date) have recorded the lowest daily extent.
22 days (30.56%) have recorded the second lowest.
9 days (12.5%) have recorded the third lowest.
65 days in total (90.28%) have been among the lowest three on record.


CT Area:
12,851,209 km2 (13 March [Day 0.1946])
Up 11,456 km2 (.09%) from previous day.
Up 126,743 km2 (1.%) over past seven days (daily average: 18,106 km2).
Up 75,382 km2 (.68%) for March (daily average: 5,799 km2).
804,933 km2 below 2000s average for this date.
413,859 km2 below 2010s average for this date.
143,527 km2 below 2015 value for this date.
680,341 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.1946) average.
Lowest March to-date average.
Lowest value for the date.
42 days this year (58.33% year-to-date) have recorded the lowest daily area.
14 days (19.44%) have recorded the second lowest.
8 days (11.11%) have recorded the third lowest.
64 days in total (88.89%) have been among the lowest three on record.




Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on March 16, 2016, 12:24:37 PM
ADS-NIPR Extent:
13,874,820 km2 (15 March)
Up 37,813 km2 (.27%) from previous day.
Down 46,246 km2  (-.33%) over past seven days (daily average: -6,607 km2).
Down 67,687 km2  (-.55%) for March (daily average: -4,512 km2).
696,999 km2 below 2000s average for this date.
373,271 km2 below 2010s average for this date.
150,382 km2 above 2015 value for this date.
791,491 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 15 March) average.
2nd lowest March to-date average.
3rd lowest value for the date.
34 days this year (45.95% year-to-date) have recorded the lowest daily extent.
23 days (31.08%) have recorded the second lowest.
10 days (13.51%) have recorded the third lowest.
67 days in total (90.54%) have been among the lowest three on record.


CT Area:
12,859,657 km2 (14 March [Day 0.1973])
Up 8,449 km2 (.07%) from previous day.
Up 136,290 km2 (1.07%) over past seven days (daily average: 19,470 km2).
Up 83,831 km2 (.75%) for March (daily average: 5,988 km2).
781,672 km2 below 2000s average for this date.
420,571 km2 below 2010s average for this date.
116,133 km2 below 2015 value for this date.
660,407 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.1973) average.
Lowest March to-date average.
Lowest value for the date.
43 days this year (58.9% year-to-date) have recorded the lowest daily area.
14 days (19.18%) have recorded the second lowest.
8 days (10.96%) have recorded the third lowest.
65 days in total (89.04%) have been among the lowest three on record.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on March 16, 2016, 05:16:09 PM
From today's NSIDC sea ice concentration data I calculate sea ice area, in the Cryosphere Today way. "day" is the day that CT normally publishes that data for the Northern Hemisphere, SH and global normally follow the next day. "CT-date" is approximately the date that CT uses.


day  CT-date       NH               SH                Global
Mon 2016.1945  +10.9 12.851103  +43.4  2.265887   +54.3 15.116990
Tue 2016.1973   +8.8 12.859880  +93.0  2.358840  +101.7 15.218720
Wed 2016.2000  +25.6 12.885500  +37.8  2.396603   +63.4 15.282103
Thu 2016.2027 -175.0 12.710511  +81.5  2.478095   -93.5 15.188606
Fri 2016.2055  +18.7 12.729209 +118.9  2.596975  +137.6 15.326184


As can be seen, CT-area (NH) will tomorrow drop an almost-near double century, possibly the start of the new melting season in the Arctic.

When NSIDC does not revise its concentration data (they do occasionally), my values are normally accurate withing a few k. Uncertainties are the exact algorithm for assumed concentration in the pole hole and some subtleties handling bad data.

In the attached graph the performance of my reverse-engineering for the past few weeks can be judged.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on March 16, 2016, 06:03:24 PM
To answer a question on the blog, I attach here yesterday's delta map (corresponding to the big drop in CT area).
Title: Re: 2016 sea ice area and extent data
Post by: Lord M Vader on March 16, 2016, 07:15:42 PM
Quite impressive with a possible century break already. But I suppose that is due to the "fish ice" in Okhotsk and Saint Lawrence? The cold weather that have been persistent for weeks in the Okhotsk have given an impressive SIE number there. I doubt we'll see ay more ice growth there until melting starts.

According to Cryosphere Today, the only other year from 2005 and onwards that have had a higher SIA in Okhotsk is 2012. On a third place we find 2007.

Wipneus:

//LMV
Title: Re: 2016 sea ice area and extent data
Post by: DoomInTheUK on March 17, 2016, 10:33:03 AM
Wipneus, to be only a few K out is an incredible effort on your part, and I thank you. You're one of the brightest stars in Neven's firmament.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on March 17, 2016, 02:11:31 PM
Quite impressive with a possible century break already.

Impressive indeed. Though for the record, Day 0.2028 has a history of largish area drops: seven of the 38 years on record have seen a loss of a century or more, including 1995, which experienced a similar drop of 174k, and 2007, which fell a whopping 240k.

Prior to today, CT SIA had increased on seven of the previous eight days, picking up +162k of ice. Today's drop clearly erases that, and then some. In fact, today's reading brings area roughly back to where it was a fortnight ago, Day 0.1671.

I don't know that 2016 reached its peak with yesterday's 12.885 million km2--we're beyond the statistically average day of maximum, though still within a standard deviation of the norm--but it seems almost certain that this year will be the first that NH SIA fails to cross 13 million.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FTtcuIMd.png&hash=a4ae1f50db810f89b45886869673dcdc)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on March 17, 2016, 03:38:02 PM
From today's NSIDC sea ice concentration data I calculate sea ice area, in the Cryosphere Today way. Here "day" is the day that CT normally publishes that data for the Northern Hemisphere, SH and global normally follow the next day. "CT-date" is approximately the date that CT uses.
When NSIDC does not revise its concentration data (they do occasionally), my values are normally accurate withing a few k. Uncertainties are the exact algorithm for assumed concentration in the pole hole and some subtleties handling bad data.


day  CT-date       NH               SH                Global
Thu 2016.2027 -175.0 12.710511  +81.5  2.478095   -93.5 15.188606
Fri 2016.2055  +18.8 12.729338 +118.9  2.596975  +137.7 15.326313
Sat 2016.2082  -18.7 12.710662 +117.9  2.714847   +99.2 15.425509


In attached dleta map, bright red (blue) indicates the concentration goes below (above) the 15% mark. Pinkish (blueish) colors when the concentration increases (decreases) by more than 7%.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on March 19, 2016, 01:33:53 PM
ADS-NIPR Extent:
13,902,527 km2 (18 March)
Up 61,022 km2 (.44%) from previous day.
Up 31,471 km2  (.23%) over past seven days (daily average: 4,496 km2).
Down 39,980 km2  (-.33%) for March (daily average: -2,221 km2).
627,429 km2 below 2000s average for this date.
353,406 km2 below 2010s average for this date.
194,522 km2 above 2015 value for this date.
777,449 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 18 March) average.
2nd lowest March to-date average.
3rd lowest value for the date.
34 days this year (44.16% year-to-date) have recorded the lowest daily extent.
23 days (29.87%) have recorded the second lowest.
13 days (16.88%) have recorded the third lowest.
70 days in total (90.91%) have been among the lowest three on record.


CT Area:
12,710,984 km2 (18 March [Day 0.2083])
Down 18,456 km2 (-.14%) from previous day.
Down 141,578 km2 (-1.1%) over past seven days (daily average: -20,225 km2).
Down 64,842 km2 (-.58%) for March (daily average: -3,602 km2).
917,629 km2 below 2000s average for this date.
557,005 km2 below 2010s average for this date.
130,950 km2 below 2015 value for this date.
918,461 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.2083) average.
Lowest March to-date average.
Lowest value for the date.
47 days this year (61.04% year-to-date) have recorded the lowest daily area.
14 days (18.18%) have recorded the second lowest.
8 days (10.39%) have recorded the third lowest.
69 days in total (89.61%) have been among the lowest three on record.



Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on March 19, 2016, 04:25:19 PM
Update for the week to March 19th

The current 5 day mean is on 14,481,80km2 while the 1 day extent is at 14,482,000km2.

The daily anomaly (compared to 81-10) is at -954,710km2, a decrease from -1,132,060km2 last week. The anomaly compared to the 07, 11 and 12 average is at -324,730km2, a decrease from -472,330km2 last week. We're currently 3rd lowest on record, down from 2nd lowest last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FlxZNDC5.png&hash=1dff5093c4bc9fde31cb3f1d5a213a7b)

The average daily change over the last 7 days was +15.6k/day, compared to the long term average of -9.8k/day, and the 07, 11 and 12 average of -5.5k/day.
The average long term change over the next week is -11.2k/day, with the 07, 11, and 12 average being -18.0k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FboRBZD9.png&hash=748919e4375fd80a5ee022293f338f8b)

The extent change so far this March is the 12th most positive on record. To achieve the largest monthly loss, a drop of at least 58.8k/day is required, while the largest monthly gain requires an increase of at least 33.1k/day and an average gain requires a loss of -18.3k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F43SYj5N.png&hash=8d1bb43d340e059798cfa6816f4f8ea1)

EDIT: Updated with data to the 19th. Though I'd be away from computer for a few days (turned out not to be the case), hence yesterdays update.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on March 21, 2016, 01:33:19 PM
ADS-NIPR Extent:
13,910,563 km2 (20 March)
Up 16,484 km2 (.12%) from previous day.
Up 37,702 km2  (.27%) over past seven days (daily average: 5,386 km2).
Down 31,944 km2  (-.26%) for March (daily average: -1,597 km2).
579,413 km2 below 2000s average for this date.
307,768 km2 below 2010s average for this date.
204,564 km2 above 2015 value for this date.
750,047 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 20 March) average.
2nd lowest March to-date average.
6th lowest value for the date.
34 days this year (43.04% year-to-date) have recorded the lowest daily extent.
23 days (29.11%) have recorded the second lowest.
13 days (16.46%) have recorded the third lowest.
70 days in total (88.61%) have been among the lowest three on record.


CT Area:
12,665,262 km2 (20 March [Day 0.2137])
Down 20,380 km2 (-.16%) from previous day.
Down 185,947 km2 (-1.45%) over past seven days (daily average: -26,564 km2).
Down 110,564 km2 (-.99%) for March (daily average: -5,528 km2).
966,433 km2 below 2000s average for this date.
591,538 km2 below 2010s average for this date.
161,749 km2 below 2015 value for this date.
1,035,412 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.2137) average.
Lowest March to-date average.
Lowest value for the date.
49 days this year (62.03% year-to-date) have recorded the lowest daily area.
14 days (17.72%) have recorded the second lowest.
8 days (10.13%) have recorded the third lowest.
71 days in total (89.87%) have been among the lowest three on record.

Title: Re: 2016 sea ice area and extent data
Post by: Xulonn on March 21, 2016, 02:59:07 PM
I am curious about the relationship between area and extent as the seasonal melting begins.  Currently, sea ice area is at a record low, and extent is not. 

When solid sheets of ice are broken up, it is intuitively obvious that the pieces would move about, open water would separate them, and extent would increase, as would the melting rate due to the increases in the total area of ice exposed to sea water.  (I am aware that the most common ice concentration cut-off point is 15%, meaning an "area" of "extent" might contain up to 85% open water.) 

Therefore if a 100km2 piece of contiguous ice fractured into small bits, and 40% of it melted, a theoretical maximum extent of 400km2 could replace 100km2 of area.  Would this mean that area would have decreased by100km2 and net extent could have increased by theoretical maximum of 300km2? (400km2 of new extent minus 100km2 reduction in area, which is included in extent.)

Of course, such a theoretical maximum would never be seen, because the ice would not all magically spread out and stop at 15% concentration.  Which is why I asked if anyone has graphed the actual relationship between area and extent.   

And a bonus question - how is the difference between "slush" and solid ice determined?  Is slush included in extent but not area?

Title: Re: 2016 sea ice area and extent data
Post by: crandles on March 21, 2016, 03:21:16 PM
Can't find a recent Capie graph (Cryosphere area per IJIS extent).

Perhaps this from long term graph page helps?

(https://sites.google.com/site/arcticseaicegraphs/_/rsrc/1452970148825/longterm/2015_Cycle_Arctic.png?height=290&width=400)
Title: Re: 2016 sea ice area and extent data
Post by: crandles on March 21, 2016, 03:40:58 PM
Dice a piece of ice 2m*2m*2m into pieces 10cm*10cm*10cm that is 8000 pieces which covers 20 times the area ie 4m^2 area changes to 80m^2 area before dealing with 15% concentration effect for extent measure.

So I think your 3 times "theoretical maximum" increase is a potentially a bit low. Don't really expect the above to happen and is likely accompanied by some melting as you indicate.
Title: Re: 2016 sea ice area and extent data
Post by: crandles on March 21, 2016, 03:58:53 PM
And a bonus question - how is the difference between "slush" and solid ice determined?  Is slush included in extent but not area?

If slush is wet enough it may appear to satellite sensors as water. Storms have been known to cause 'flash melting' suddenly a lot of ice disappears but some of this can return over next 2 or 3 days as ocean gets calmer and the ice dry enough to be detected again.

If the ice is detectable it is included in area according to percent coverage estimated and included in extent if over the 15% threshold.
Title: Re: 2016 sea ice area and extent data
Post by: DavidR on March 21, 2016, 04:41:25 PM
I am curious about the relationship between area and extent as the seasonal melting begins.  Currently, sea ice area is at a record low, and extent is not. 

When solid sheets of ice are broken up, it is intuitively obvious that the pieces would move about, open water would separate them, and extent would increase, as would the melting rate due to the increases in the total area of ice exposed to sea water.  (I am aware that the most common ice concentration cut-off point is 15%, meaning an "area" of "extent" might contain up to 85% open water.) 

Therefore if a 100km2 piece of contiguous ice fractured into small bits, and 40% of it melted, a theoretical maximum extent of 400km2 could replace 100km2 of area.  Would this mean that area would have decreased by100km2 and net extent could have increased by theoretical maximum of 300km2? (400km2 of new extent minus 100km2 reduction in area, which is included in extent.)
In this example the remaining ice would still be considered 'area' so area would decrease by 40 km2 and extent could  increase as you say by 300km2. However a more likely scenario is that the average coverage for the extent would be near 60% and with your assumed 40% melt there would be virtually no  change in extent.

Its also worth noting that there would be virtually  no increase in exposure to water as the ice would typically be only 0 - 2 metres thick, which in a 1 km2 bit would add less than 1% to the total area exposed to  water. 
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on March 22, 2016, 03:28:08 PM
By Thursday, the Arctic maximum is again very close.

From today's NSIDC sea ice concentration data I calculate sea ice area, in the Cryosphere Today way. Here "day" is the day that CT normally publishes that data for the Northern Hemisphere, SH and global normally follow the next day. "CT-date" is approximately the date that CT uses.
When NSIDC does not revise its concentration data (they do occasionally), my values are normally accurate withing a few k. Uncertainties are the exact algorithm for assumed concentration in the pole hole and some subtleties handling bad data.


day  CT-date       NH               SH                Global
Tue 2016.2164  +12.2 12.677734  +37.2  2.930337   +49.4 15.608071
Wed 2016.2192  +48.3 12.726083  +40.5  2.970887   +88.9 15.696970
Thu 2016.2219  +82.5 12.808631 +121.1  3.091945  +203.6 15.900576


In attached delta map, bright red (blue) indicates the concentration goes below (above) the 15% mark. Pinkish (blueish) colors when the concentration indecreases (deincreases) by more than 7%.

[UPDATE: in my description of the meaning of pink and blueish, I got them wrong. Corrected, and thanks Tor, for pointing this out.]

A large increase is in the St.Lawrence region, that may evaporate (so to speak) again on Friday.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on March 23, 2016, 03:30:31 PM
Small increase, still below current maximum.

From today's NSIDC sea ice concentration data I calculate sea ice area, in the Cryosphere Today way. Here "day" is the day that CT normally publishes that data for the Northern Hemisphere, SH and global normally follow the next day. "CT-date" is approximately the date that CT uses.
When NSIDC does not revise its concentration data (they do occasionally), my values are normally accurate withing a few k. Uncertainties are the exact algorithm for assumed concentration in the pole hole and some subtleties handling bad data.


day  CT-date       NH               SH                Global
Wed 2016.2192  +48.3 12.726083  +40.5  2.970887   +88.9 15.696970
Thu 2016.2219  +82.6 12.808706 +121.1  3.091945  +203.7 15.900651
Fri 2016.2247  +17.7 12.826397 +188.5  3.280477  +206.2 16.106874


In attached delta map, bright red (blue) indicates the concentration goes below (above) the 15% mark. Pinkish (blueish) colors when the concentration decreases (increases) by more than 7%.

Increases in many places (st.Lawrence, Baffin, Barents, Bering) is almost completely offset by a crash in Okhotsk.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on March 24, 2016, 01:17:02 PM
ADS-NIPR Extent:
13,899,979 km2 (23 March)
Down 26,173 km2 (-.19%) from previous day.
Up 18,110 km2  (.13%) over past seven days (daily average: 2,587 km2).
Down 42,528 km2  (-.35%) for March (daily average: -1,849 km2).
553,337 km2 below 2000s average for this date.
260,021 km2 below 2010s average for this date.
65,094 km2 above 2015 value for this date.
670,420 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 23 March) average.
2nd lowest March to-date average.
5th lowest value for the date.
34 days this year (41.46% year-to-date) have recorded the lowest daily extent.
23 days (28.05%) have recorded the second lowest.
13 days (15.85%) have recorded the third lowest.
70 days in total (85.37%) have been among the lowest three on record.


CT Area:
12,808,733 km2 (23 March [Day 0.2219])
Up 82,634 km2 (.65%) from previous day.
Up 98,375 km2 (.77%) over past seven days (daily average: 14,054 km2).
Up 32,906 km2 (.3%) for March (daily average: 1,431 km2).
738,403 km2 below 2000s average for this date.
408,377 km2 below 2010s average for this date.
90,013 km2 below 2015 value for this date.
732,717 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.2219) average.
Lowest March to-date average.
2nd lowest value for the date.
51 days this year (62.2% year-to-date) have recorded the lowest daily area.
15 days (18.29%) have recorded the second lowest.
8 days (9.76%) have recorded the third lowest.
74 days in total (90.24%) have been among the lowest three on record.

Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on March 24, 2016, 03:42:15 PM
Very small increase, still below current maximum.

From today's NSIDC sea ice concentration data I calculate sea ice area, in the Cryosphere Today way. Here "day" is the day that CT normally publishes that data for the Northern Hemisphere, SH and global normally follow the next day. "CT-date" is approximately the date that CT uses.
When NSIDC does not revise its concentration data (they do occasionally), my values are normally accurate withing a few k. Uncertainties are the exact algorithm for assumed concentration in the pole hole and some subtleties handling bad data.

day  CT-date       NH               SH                Global
Thu 2016.2219  +82.6 12.808706 +121.1  3.091945  +203.7 15.900651
Fri 2016.2247  +17.8 12.826516 +188.5  3.280477  +206.3 16.106993
Sat 2016.2274   +4.4 12.830869  +53.6  3.334093   +58.0 16.164962


In attached delta map, bright red (blue) indicates the concentration goes below (above) the 15% mark. Pinkish (blueish) colors when the concentration decreases (increases) by more than 7%.

In the St.Lawrence and the Baffin region area dropped big way (-83k), other regions area increased with smaller amounts.


Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on March 25, 2016, 03:23:28 PM
Well, the +55k is exactly what is required to equal the maximum (12.88502)  :o
Too close to be certain that Sunday will set a new max. But judging by the deviation of my results during the last few weeks, it is likely.

From today's NSIDC sea ice concentration data I calculate sea ice area, in the Cryosphere Today way. Here "day" is the day that CT normally publishes that data for the Northern Hemisphere, SH and global normally follow the next day. "CT-date" is approximately the date that CT uses.
When NSIDC does not revise its concentration data (they do occasionally), my values are normally accurate withing a few k. Uncertainties are the exact algorithm for assumed concentration in the pole hole and some subtleties handling bad data.


day  CT-date       NH               SH                Global
Fri 2016.2247  +17.8 12.826516 +188.5  3.280477  +206.3 16.106993
Sat 2016.2274   +4.3 12.830855  +53.6  3.334093   +58.0 16.164948
Sun 2016.2301  +55.0 12.885890  +42.4  3.376455   +97.4 16.262345


In attached delta map, bright red (blue) indicates the concentration goes below (above) the 15% mark. Pinkish (blueish) colors when the concentration decreases (increases) by more than 7%.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on March 26, 2016, 01:19:29 PM
ADS-NIPR Extent:
13,823,186 km2 (25 March)
Down 38,851 km2 (-.28%) from previous day.
Down 79,341 km2  (-.57%) over past seven days (daily average: -11,334 km2).
Down 119,321 km2  (-.98%) for March (daily average: -4,773 km2).
621,170 km2 below 2000s average for this date.
328,574 km2 below 2010s average for this date.
31,193 km2 below 2015 value for this date.
728,181 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 25 March) average.
2nd lowest March to-date average.
2nd lowest value for the date.
34 days this year (40.48% year-to-date) have recorded the lowest daily extent.
24 days (28.57%) have recorded the second lowest.
13 days (15.48%) have recorded the third lowest.
71 days in total (84.52%) have been among the lowest three on record.


CT Area:
12,830,809 km2 (25 March [Day 0.2274])
Up 4,214 km2 (.03%) from previous day.
Up 119,824 km2 (.94%) over past seven days (daily average: 17,118 km2).
Up 54,982 km2 (.49%) for March (daily average: 2,199 km2).
660,695 km2 below 2000s average for this date.
383,866 km2 below 2010s average for this date.
200,314 km2 below 2015 value for this date.
714,911 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.2274) average.
Lowest March to-date average.
3rd lowest value for the date.
51 days this year (60.71% year-to-date) have recorded the lowest daily area.
15 days (17.86%) have recorded the second lowest.
10 days (11.9%) have recorded the third lowest.
76 days in total (90.48%) have been among the lowest three on record.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on March 26, 2016, 03:24:53 PM
The situation is a bit clearer now. Tomorrow will very likely a new max, which will be followed by a (quite certain) new max on Monday. The margins are small, but big enough to predict what CT will record.

From today's NSIDC sea ice concentration data I calculate sea ice area, in the Cryosphere Today way. Here "day" is the day that CT normally publishes that data for the Northern Hemisphere, SH and global normally follow the next day. "CT-date" is approximately the date that CT uses.
When NSIDC does not revise its concentration data (they do occasionally), my values are normally accurate withing a few k. Uncertainties are the exact algorithm for assumed concentration in the pole hole and some subtleties handling bad data.

day  CT-date       NH               SH                Global
Sat 2016.2274   +4.3 12.830855  +53.6  3.334093   +58.0 16.164948
Sun 2016.2301  +55.3 12.886181  +42.4  3.376455   +97.7 16.262636
Mon 2016.2329   +4.8 12.891012 +113.5  3.489908  +118.3 16.380920

In attached delta map, bright red (blue) indicates the concentration goes below (above) the 15% mark. Pinkish (blueish) colors when the concentration decreases (increases) by more than 7%.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on March 26, 2016, 07:58:22 PM
The situation is a bit clearer now. Tomorrow will very likely a new max, which will be followed by a (quite certain) new max on Monday. The margins are small, but big enough to predict what CT will record.

From today's NSIDC sea ice concentration data I calculate sea ice area, in the Cryosphere Today way. Here "day" is the day that CT normally publishes that data for the Northern Hemisphere, SH and global normally follow the next day. "CT-date" is approximately the date that CT uses.
When NSIDC does not revise its concentration data (they do occasionally), my values are normally accurate withing a few k. Uncertainties are the exact algorithm for assumed concentration in the pole hole and some subtleties handling bad data.

day  CT-date       NH               SH                Global
Sat 2016.2274   +4.3 12.830855  +53.6  3.334093   +58.0 16.164948
Sun 2016.2301  +55.3 12.886181  +42.4  3.376455   +97.7 16.262636
Mon 2016.2329   +4.8 12.891012 +113.5  3.489908  +118.3 16.380920

In attached delta map, bright red (blue) indicates the concentration goes below (above) the 15% mark. Pinkish (blueish) colors when the concentration decreases (increases) by more than 7%.

Definitely looks like a new 2016 maximum on Day 0.2301, then another on 0.2329, though still well within record low max territory (2011's 13.144 million km2 is safe), and, if 0.2329 is the end of it, still three days earlier than 2012's max on 0.2411 (and still 818k below that record year's maximum).
Title: Re: 2016 sea ice area and extent data
Post by: Neven on March 26, 2016, 09:37:32 PM
If the max does occur after 2012's date will it be the latest on record?
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on March 27, 2016, 02:54:08 PM
If the max does occur after 2012's date will it be the latest on record?

That would be correct. In descending order:

2012 -- 0.2439
2016* -- 0.2301
1985 -- 0.2246
1999 & 2003 -- 0.2219
1984 & 2014 -- 0.2192

* To-date

Of course, there doesn't appear to be any correlation between the date of maximum and the area that remains at minimum, mostly because a few days of anomalous weather in March and an overnight difference of a few thousand square miles of ice can cause a much earlier or much later than average maximum to occur. 2012's max, the latest ever, didn't seem to affect that year's recordbreaking minimum, while last year's earliest-ever maximum lead to only the sixth-lowest minimum. IOW, max dates are probably of no true scientific value. Which, of course, makes me ask myself why I bother tracking them. ;)

Anyway:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FplHXLFN.png&hash=7ff93ce1082244c4e3997ae14f5d8a89)
Title: Re: 2016 sea ice area and extent data
Post by: Neven on March 27, 2016, 03:29:20 PM
Thanks, Jim.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on March 27, 2016, 04:10:25 PM
Another small uptick expected on CT's update on Tues day. So a higher and a later maximum.

From today's NSIDC sea ice concentration data I calculate sea ice area, in the Cryosphere Today way. Here "day" is the day that CT normally publishes that data for the Northern Hemisphere, SH and global normally follow the next day. "CT-date" is approximately the date that CT uses.
When NSIDC does not revise its concentration data (they do occasionally), my values are normally accurate withing a few k. Uncertainties are the exact algorithm for assumed concentration in the pole hole and some subtleties handling bad data.

day  CT-date       NH               SH                Global
Sun 2016.2301  +55.3 12.886181  +53.6  3.334093  +108.9 16.220274
Mon 2016.2329   +4.7 12.890922  +42.4  3.376455   +47.1 16.267377
Tue 2016.2356   +7.9 12.898859 +113.5  3.489908  +121.4 16.388767

In attached delta map, bright red (blue) indicates the concentration goes below (above) the 15% mark. Pinkish (blueish) colors when the concentration decreases (increases) by more than 7%.

A big drop in the Barents section (-55k) is compensated by many smaller increases elsewhere.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on March 27, 2016, 08:12:00 PM
Update for the week to March 26th

The current 5 day mean is on 14,482,200km2 while the 1 day extent is at 14,380,000km2.

The daily anomaly (compared to 81-10) is at -875,990km2, a decrease from -954,710km2 last week. The anomaly compared to the 07, 11 and 12 average is at -198,530km2, a decrease from -324,730km2 last week. We're currently 6th lowest on record, down from 3rd lowest last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FVhHDeMP.png&hash=9561646ecdab894be6ba8cda15b7f940)

The average daily change over the last 7 days was +0.1k/day, compared to the long term average of -11.2k/day, and the 07, 11 and 12 average of -18.0k/day.
The average long term change over the next week is -14.5k/day, with the 07, 11, and 12 average being -4.9k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FhF2mNah.png&hash=e2734e1886a165a73a903a79be684c70)

The extent change so far this March is the 10th most positive on record. To achieve the largest monthly loss, a drop of at least 141.0k/day is required, while the largest monthly gain requires an increase of at least 79.5k/day and an average gain requires a loss of -44.0k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FuTXcK9Q.png&hash=1375bef61f25b7a1d75b7862eae71da0)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on March 28, 2016, 04:40:15 PM
Another uptick expected on CT's update on Wednesday. So a higher and a later maximum.

From today's NSIDC sea ice concentration data I calculate sea ice area, in the Cryosphere Today way. Here "day" is the day that CT normally publishes that data for the Northern Hemisphere, SH and global normally follow the next day. "CT-date" is approximately the date that CT uses.
When NSIDC does not revise its concentration data (they do occasionally), my values are normally accurate withing a few k. Uncertainties are the exact algorithm for assumed concentration in the pole hole and some subtleties handling bad data.

day  CT-date       NH               SH                Global
Mon 2016.2329   +4.7 12.890922 +113.5  3.489908  +118.2 16.380830
Tue 2016.2356   +8.2 12.899085 +111.1  3.600973  +119.2 16.500058
Wed 2016.2384  +22.0 12.921042 +120.3  3.721245  +142.2 16.642287

In attached delta map, bright red (blue) indicates the concentration goes below (above) the 15% mark. Pinkish (blueish) colors when the concentration decreases (increases) by more than 7%.

Small regional changes only, for a change.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on March 29, 2016, 04:21:44 PM
A big century drop almost certainly ends the march to the top, and starts the race to the bottom.

From today's NSIDC sea ice concentration data I calculate sea ice area, in the Cryosphere Today way. Here "day" is the day that CT normally publishes that data for the Northern Hemisphere, SH and global normally follow the next day. "CT-date" is approximately the date that CT uses.
When NSIDC does not revise its concentration data (they do occasionally), my values are normally accurate withing a few k. Uncertainties are the exact algorithm for assumed concentration in the pole hole and some subtleties handling bad data.

day  CT-date       NH               SH                Global
Tue 2016.2356   +8.2 12.899085 +111.1  3.600973  +119.2 16.500058
Wed 2016.2384  +22.1 12.921232 +120.3  3.721245  +142.4 16.642477
Thu 2016.2411 -124.4 12.796836 +104.9  3.826190   -19.5 16.623026

In attached delta map, bright red (blue) indicates the concentration goes below (above) the 15% mark. Pinkish (blueish) colors when the concentration decreases (increases) by more than 7%.

Big drops in the Barents section and Okhotsk region.
Title: Re: 2016 sea ice area and extent data
Post by: Neven on March 29, 2016, 04:23:08 PM
A big century drop almost certainly ends the march to the top, and starts the race to the bottom.

Not latest on record...  :'(  ;)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on March 29, 2016, 04:30:29 PM
A big century drop almost certainly ends the march to the top, and starts the race to the bottom.

Not latest on record...  :'(  ;)

True...but only by a day. And still pretty far outside the norm:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fmhi0fvx.png&hash=199f5426dc5cf65c85913ec15ffb4364)

It's interesting to note that, despite occurring a full 40 days after last year's maximum, 2016 nevertheless has roughly 200,000 square kilometers less area today than on the same day last year.


Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on March 29, 2016, 04:45:05 PM
A big century drop almost certainly ends the march to the top, and starts the race to the bottom.

Not latest on record...  :'(  ;)

True...but only by a day. ...


According to NSIDC, the latest on record is April 2,2010:

"The date of the maximum has varied considerably over the years, occurring as early as February 24 in 1996 and as late as April 2 in 2010."

http://nsidc.org/arcticseaicenews/2015/03/ (http://nsidc.org/arcticseaicenews/2015/03/)
Title: Re: 2016 sea ice area and extent data
Post by: Neven on March 29, 2016, 04:48:12 PM
According to NSIDC, the latest on record is April 2,2010:

"The date of the maximum has varied considerably over the years, occurring as early as February 24 in 1996 and as late as April 2 in 2010."

http://nsidc.org/arcticseaicenews/2015/03/ (http://nsidc.org/arcticseaicenews/2015/03/)

Yes, but that's for NSIDC SIE. We were talking about CT SIA.

It's interesting to note that, despite occurring a full 40 days after last year's maximum, 2016 nevertheless has roughly 200,000 square kilometers less area today than on the same day last year.

That's why I 'wanted' it to be latest. Lowest and latest is a cool combination, as in freaky.

Thanks for the image. Very nice.
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on March 29, 2016, 04:55:58 PM
According to NSIDC, the latest on record is April 2,2010:

"The date of the maximum has varied considerably over the years, occurring as early as February 24 in 1996 and as late as April 2 in 2010."

http://nsidc.org/arcticseaicenews/2015/03/ (http://nsidc.org/arcticseaicenews/2015/03/)

Yes, but that's for NSIDC SIE. We were talking about CT SIA.

It's interesting to note that, despite occurring a full 40 days after last year's maximum, 2016 nevertheless has roughly 200,000 square kilometers less area today than on the same day last year.

That's why I 'wanted' it to be latest. Lowest and latest is a cool combination, as in freaky.

Thanks for the image. Very nice.

Thanks for the clarification. It is true, this year had a very interesting ASI freezing season.
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on March 29, 2016, 05:19:07 PM
first high below 13k, know it's not good as per climate development but it's a first for the records and hence further puts deniers into bad light which is good. facts once more prevail over illusions (or bad intentions)
Title: Re: 2016 sea ice area and extent data
Post by: oren on March 29, 2016, 06:00:10 PM
A big century drop almost certainly ends the march to the top, and starts the race to the bottom.

From today's NSIDC sea ice concentration data I calculate sea ice area, in the Cryosphere Today way. Here "day" is the day that CT normally publishes that data for the Northern Hemisphere, SH and global normally follow the next day. "CT-date" is approximately the date that CT uses.
When NSIDC does not revise its concentration data (they do occasionally), my values are normally accurate withing a few k. Uncertainties are the exact algorithm for assumed concentration in the pole hole and some subtleties handling bad data.

day  CT-date       NH               SH                Global
Tue 2016.2356   +8.2 12.899085 +111.1  3.600973  +119.2 16.500058
Wed 2016.2384  +22.1 12.921232 +120.3  3.721245  +142.4 16.642477
Thu 2016.2411 -124.4 12.796836 +104.9  3.826190   -19.5 16.623026

In attached delta map, bright red (blue) indicates the concentration goes below (above) the 15% mark. Pinkish (blueish) colors when the concentration decreases (increases) by more than 7%.

Big drops in the Barents section and Okhotsk region.

Barents gave and Barents took away. Blessed be Barents...
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on March 30, 2016, 04:49:48 PM
Another century drop brings CT-area 260k below the max, now quite certain the final one.

From today's NSIDC sea ice concentration data I calculate sea ice area, in the Cryosphere Today way. Here "day" is the day that CT normally publishes that data for the Northern Hemisphere, SH and global normally follow the next day. "CT-date" is approximately the date that CT uses.
When NSIDC does not revise its concentration data (they do occasionally), my values are normally accurate withing a few k. Uncertainties are the exact algorithm for assumed concentration in the pole hole and some subtleties handling bad data.

day  CT-date       NH               SH                Global
Wed 2016.2384  +22.1 12.921232 +120.3  3.721245  +142.4 16.642477
Thu 2016.2411 -124.3 12.796913 +104.9  3.826190   -19.4 16.623103
Fri 2016.2438 -137.1 12.659838  +55.2  3.881395   -81.9 16.541233

In attached delta map, bright red (blue) indicates the concentration goes below (above) the 15% mark. Pinkish (blueish) colors when the concentration decreases (increases) by more than 7%.

Big drops in the Barents section: Barents, CAB and Kara.
Title: Re: 2016 sea ice area and extent data
Post by: Lord M Vader on March 30, 2016, 09:06:06 PM
Wipneus, if the most recent GFS 12z run is correct, St Lawrence should see warm temperatures in the range of 0-10oC through the weekend before the cold Arctic blast arrives. The fragile ice there should get a few really tough days there.

Btw, Berings Sea might see some ice transport into nowhere as northerly winds may be persistent there for a week or so..

Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on March 30, 2016, 09:35:51 PM
...Another century drop brings CT-area 260k below the max, now quite certain the final one.

Yes, it does. If those two decreases happen, 2016 will be back in first place (lowest) for the day. Of greater interest, 2016 will have reached its maximum just one day later than did 2012--though 2016 will have roughly  than a million square kilometers of ice less than 2012 did on the same date. That's--obviously--quite a head start...
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on March 31, 2016, 05:31:21 PM
CT-area will drop Saturday further by -39k.

NSIDC is more interesting today, dropping -162k.

Regionally the drop is mostly in St.Lawrence and the ocean of Newfoundland (part of the Baffin region), with a share of -140k!

Here are the numbers for regional extent and area:

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2016-03-30 12:00  Values in 1000 km^2  Anomalies are from the 1981-2010 mean values

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4394.2  -17.1   -60.9    935.1   +0.0    +0.0    733.9   +0.0    +0.0
               Kara Sea             Barents Sea           Greenland Sea
   879.5  -12.3   -19.1    378.8   -4.6  -500.4    566.8   +6.2  -206.0
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
  1364.1  -42.5    +3.5     53.7  -97.1   -99.7   1230.5   +0.0    +0.1
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   747.0   +0.0    +0.0    527.6   +0.0    +0.0    602.9   +0.0    +0.0
             Bering Sea          Sea of Okhotsk                   Lakes
   666.3   -3.0  -108.1    902.7  +19.9   -56.7    253.1  +19.2   +48.3
          Other regions       Total (ex. lakes)
   179.3  -11.8   -61.3  14162.4 -162.3 -1108.6

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4242.4   -4.0  -136.3    917.0   -0.3    +1.4    714.4   -2.5    +4.3
               Kara Sea             Barents Sea           Greenland Sea
   780.7  -22.7   -72.4    197.0   +0.6  -480.0    397.1   +4.8  -165.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
  1090.9   -9.4   -15.5     16.4  -30.5   -57.1   1150.5   +6.5    +0.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   721.9   -2.8    +5.8    518.6   +2.8    +7.9    599.0   -0.6   +17.0
             Bering Sea          Sea of Okhotsk                   Lakes
   432.3   +4.3  -102.4    581.0   +8.2   -73.4    146.1  +15.8   +13.5
          Other regions       Total (ex. lakes)
    58.3   -5.2   -54.6  12417.6  -50.9 -1119.9



And the delta map, bright red (blue) indicates the concentration goes below (above) the 15% mark. Pinkish (blueish) colors when the concentration decreases (increases) by more than 7%.

Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on April 01, 2016, 02:33:15 PM
ADS-NIPR Extent:
13,496,200 km2 (31 March)
Down 446,307 km2 (3.2%) from 2016 maximum of 13,942,507 km2 on 29 February.
10,318,745 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 64,721 km2 (-.48%) from previous day.
Down 365,837 km2  (-2.64%) over past seven days (daily average: -52,262 km2).
Down 446,307 km2  (-3.65%) for March (daily average: -14,397 km2).
777,590 km2 below 2000s average for this date.
566,852 km2 below 2010s average for this date.
161,940 km2 below 2015 value for this date.
1,034,607 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 31 March) average.
2nd lowest March monthly average.
Lowest value for the date.
36 days this year (40% year-to-date) have recorded the lowest daily extent.
27 days (30%) have recorded the second lowest.
14 days (15.56%) have recorded the third lowest.
77 days in total (85.56%) have been among the lowest three on record.



CT Area:
12,658,473 km2 (31 March [Day 0.2439])
Down 262,885 km2 (2.03%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
10,424,464 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 138,455 km2 (-1.08%) from previous day.
Down 168,121 km2 (-1.31%) over past seven days (daily average: -24,017 km2).
Down 117,354 km2 (-1.05%) for March (daily average: -3,786 km2).
731,603 km2 below 2000s average for this date.
567,563 km2 below 2010s average for this date.
331,673 km2 below 2015 value for this date.
1,047,931 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.2439) average.
Lowest March monthly average.
Lowest value for the date.
52 days this year (57.78% year-to-date) have recorded the lowest daily area.
17 days (18.89%) have recorded the second lowest.
11 days (12.22%) have recorded the third lowest.
80 days in total (88.89%) have been among the lowest three on record.

Today's fun facts:

1) Today marks the first time both extent and area have been 1,000,000 million square kilometers below 2012's same day readings.

2) The maximum extents for 2015 and 2016 were basically identical, coming in at 13,942,060 km2 and 13,942,507 km2, respectively. That's a difference of just 447km2, or roughly the size of Winnipeg, Canada. Put another way, 2016's maximum was just 0.003% higher than 2015's.




Title: Re: 2016 sea ice area and extent data
Post by: Espen on April 01, 2016, 06:48:09 PM
And for the first time below 13,500,000 km2 in March (13,496,200 km2 (31 March))
Title: Re: 2016 sea ice area and extent data
Post by: Neven on April 01, 2016, 08:17:39 PM
CT SIA has noted 5 century breaks so far, together with 2007 the highest number of century breaks in the 2007-2016 record.
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on April 02, 2016, 10:58:10 PM
One courious thing about NSIDC Charctic graph is that it is comparing April 2, 2006 with April 1, 2016. I would say that this happens because 2016 is a leap year. So today it looks that 2006 and 2016 are even. With this tendency, I believe that for NSIDC, tomorrow 2016 will be first on record.

Year          Apr 1     Apr 2      Apr 3
2006      14,232  14,241   14,235
2016      14,241

Title: Re: 2016 sea ice area and extent data
Post by: ktonine on April 03, 2016, 12:25:11 AM
One courious thing about NSIDC Charctic graph is that it is comparing April 2, 2006 with April 1, 2016. I would say that this happens because 2016 is a leap year.

The spring equinox fell on March 20th in both 2006 and 2016.  2016's vernal equinox fell about 14 hours earlier than 2006's - so leap year should have little effect
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on April 03, 2016, 01:33:51 AM
One courious thing about NSIDC Charctic graph is that it is comparing April 2, 2006 with April 1, 2016. I would say that this happens because 2016 is a leap year.

The spring equinox fell on March 20th in both 2006 and 2016.  2016's vernal equinox fell about 14 hours earlier than 2006's - so leap year should have little effect

If you make a table by the day of the year, April 2, 2006 and April 1, 2016 will be day 92 of the year. 2006 will have 365 days and 2016 will have 366 days.
I haven´t check it, but it is posible that graphs like Charctic will only use the first 365 days in any year, so it will disregard Dic 31 on all leap years. I will check it later.
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on April 03, 2016, 02:47:06 AM
Leap years (like 2004, 2008 and 2012) have an extra day at the end of the graph. So, on the Charctic, NSIDC compares day 92 with day 92, but it does not adjust the graph to compare April 1st., 2006 (not leap year) with April 1st., 2016 (leap year).

Edit: Being April 1st April fools, It is ok that 2006 and 2016 look even, but their are not.  ;D
Title: Re: 2016 sea ice area and extent data
Post by: ktonine on April 03, 2016, 10:51:59 AM
Leap years (like 2004, 2008 and 2012) have an extra day at the end of the graph. So, on the Charctic, NSIDC compares day 92 with day 92, but it does not adjust the graph to compare April 1st., 2006 (not leap year) with April 1st., 2016 (leap year).

Edit: Being April 1st April fools, It is ok that 2006 and 2016 look even, but their are not.  ;D

Juan - my point is that calendar dates are not important; it's the equinoxes and solstices that determine the insolation.  We should compare by these dates regardless of calendar date or leap year.
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on April 03, 2016, 05:54:44 PM
The true is that the form in which the leap years are manage will always be problematic, so it is just knowing the form in which the sources manage the leap years, to clearly understand their graphs.
There are other things that concern me more. After the huge melt that ASI had on September 2007, the Director of NSIDC Mark Serreze gave a conference at the American Geophysical Union (AGU). He recognized that he was expecting an ice-free Arctic by 2030. He said that the melt will accelerate and he talked about the possibility that 2007 was the year of the tipping point.
We have a new impressive record at 2012. We also have two years similar to 2007: 2011 and 2015. So, why the NSIDC show a linear trend, like if we have 40 or 50 years more? If scientific people of NSIDC expressed their concern of IPCC models at 2006, before the melt of 2007, why they have say nothing on the new IPCC models? Why we have a new definition of ice-free Arctic, in which we need 5 consecutive years of SIE under 1 million km2 to consider that the world is experience a ice-free Arctic? Why humanity keeps talking about extent, when we should agree that what matters is volume and the tendency of volume is an immediate colapse?
So, the big proportion of the humans will be surprise, when the governments will make official that Climate Change is not going to melt the Arctic Sea Ice at 2100, but in 1 to 10 years.
I understand your point about the equinoxes and solstices, but what I think is that as community, it is more important that we push to make everybody understand that the Arctic Sea Ice has less than 10 years to disappear.

2007 Mark Serreze conference at AGU: http://www.agu.org/webcast/fm07/Serreze/index.html (http://www.agu.org/webcast/fm07/Serreze/index.html)

Edit: Pardon my English  :( Corrections and addendums in Italic.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on April 04, 2016, 02:39:35 PM
ADS-NIPR Extent:
13,447,985 km2 (03 April)
Down 494,522 km2 (3.55%) from 2016 maximum of 13,942,507 km2 on 29 February.
10,270,530 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Up 3,228 km2 (.02%) from previous day.
Down 352,092 km2  (-2.55%) over past seven days (daily average: -50,299 km2).
Down 48,215 km2  (-.39%) for April (daily average: -16,072 km2).
747,246 km2 below 2000s average for this date.
540,242 km2 below 2010s average for this date.
96,810 km2 below 2015 value for this date.
1,027,163 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 03 April) average.
Lowest April to-date average.
Lowest value for the date.
39 days this year (41.94% year-to-date) have recorded the lowest daily extent.
27 days (29.03%) have recorded the second lowest.
14 days (15.05%) have recorded the third lowest.
80 days in total (86.02%) have been among the lowest three on record.


CT Area:
12,532,279 km2 (03 April [Day 0.2521])
Down 389,079 km2 (3.01%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
10,298,270 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 58,005 km2 (-.46%) from previous day.
Down 358,490 km2 (-2.78%) over past seven days (daily average: -51,213 km2).
Down 126,194 km2 (-1.13%) for April (daily average: -42,065 km2).
795,145 km2 below 2000s average for this date.
610,679 km2 below 2010s average for this date.
449,670 km2 below 2015 value for this date.
946,886 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.2521) average.
Lowest April to-date average.
Lowest value for the date.
55 days this year (59.14% year-to-date) have recorded the lowest daily area.
17 days (18.28%) have recorded the second lowest.
11 days (11.83%) have recorded the third lowest.
83 days in total (89.25%) have been among the lowest three on record.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on April 04, 2016, 04:42:20 PM
Update for the week to April 2nd

The current 5 day mean is on 14,193,000km2 while the 1 day extent is at 14,124,000km2.

The daily anomaly (compared to 81-10) is at -1,063,590km2, an increase from -875,990km2 last week. The anomaly compared to the 07, 11 and 12 average is at -453,470km2, an increase from -198,530km2 last week. We're currently lowest on record, up from 6th lowest last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FBnk7Bay.png&hash=eb892fe5f2f0bbac92699ddfdf770e03)

The average daily change over the last 7 days was -41.3k/day, compared to the long term average of -14.5k/day, and the 07, 11 and 12 average of -4.9k/day.
The average long term change over the next week is -32.7k/day, with the 07, 11, and 12 average being -28.5k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FeOMorhy.png&hash=df279a1e0c25e0eb95295a4491aee813)

The extent drop so far this April is the 7th largest record. To achieve the largest monthly loss, a drop of at least 53.5k/day is required, while the smallest loss requires a drop of less than 20.5k/day and an average loss requires a drop of 34.9k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fi9FQssG.png&hash=462685367c1173c448915daf25fbd44a)

The extent change in March was the 16th most negative on record, while the average extent was the 2nd lowest on record.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FWSePJbE.png&hash=6995495b8c0b6e8d9860dd79b0ab1578)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FntHu44p.png&hash=eebc72ff8ae484008c6e394bf98926db)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on April 06, 2016, 02:12:59 PM
ADS-NIPR Extent:
13,408,667 km2 (05 April)
Down 533,840 km2 (3.83%) from 2016 maximum of 13,942,507 km2 on 29 February.
10,231,212 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 11,253 km2 (-.08%) from previous day.
Down 288,676 km2  (-2.11%) over past seven days (daily average: -41,239 km2).
Down 87,533 km2  (-.72%) for April (daily average: -17,507 km2).
724,246 km2 below 2000s average for this date.
496,527 km2 below 2010s average for this date.
84,157 km2 below 2015 value for this date.
883,909 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 05 April) average.
Lowest April to-date average.
Lowest value for the date.
41 days this year (43.16% year-to-date) have recorded the lowest daily extent.
27 days (28.42%) have recorded the second lowest.
14 days (14.74%) have recorded the third lowest.
82 days in total (86.32%) have been among the lowest three on record.


CT Area:
12,490,260 km2 (05 April [Day 0.2576])
Down 431,098 km2 (3.34%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
10,256,251 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 20,014 km2 (-.16%) from previous day.
Down 431,098 km2 (-3.37%) over past seven days (daily average: -61,585 km2).
Down 168,213 km2 (-1.51%) for April (daily average: -33,643 km2).
807,178 km2 below 2000s average for this date.
598,135 km2 below 2010s average for this date.
354,999 km2 below 2015 value for this date.
976,908 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.2576) average.
lowest April to-date average.
Lowest value for the date.
57 days this year (60% year-to-date) have recorded the lowest daily area.
17 days (17.89%) have recorded the second lowest.
11 days (11.58%) have recorded the third lowest.
85 days in total (89.47%) have been among the lowest three on record.



Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on April 06, 2016, 05:36:26 PM
My CT-area-like calculation results in -360k, while NSIDC gives a +128k increase. These figures are caused by some flaw in the SSMIS data as can be seen by the attached NSIDC browse image.

No information from NSIDC I have seen. I got  an email from osi-saf this morning about the situation:
Quote
OSI SAF Service Message #1227

o Title :
Missing sector in OSI SAF sea ice products

o Product :
Sea Ice

o Date :
2016-04-06

o From :
 MET Norway Local Manager

o Message :
The OSI SAF sea ice products distributed this morning (labelled 20160405)
have a sector of missing data due to SSMIS data outage yesterday. The data
provider (NOAA) is looking into the problem. Service message will follow
when we have more news from NOAA.

Antarctic data is similarly affected.
Title: Re: 2016 sea ice area and extent data
Post by: Neven on April 06, 2016, 06:20:15 PM
But Wip, does that mean the -360K is wrong, or is the +128K wrong?  :)
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on April 06, 2016, 06:24:02 PM
But Wip, does that mean the -360K is wrong, or is the +128K wrong?  :)

the +128 are wrong, the glitches produce mesh ice over open waters LOL
Title: Re: 2016 sea ice area and extent data
Post by: AmbiValent on April 07, 2016, 10:12:18 AM
That would be open water at and near the North Pole, so I guess the increase is the correct data (this time).
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on April 07, 2016, 11:13:06 AM
of course i don't mean that over ice but that over open waters like the norwegian cost north of northcape there is definitely no increase of that scale

This link is for extent, but then that extent curve as well shows clearly that there cannot be an increase in area of that scale while the extent droped like this. i just linked this because the images are as per april 5th and that one is as of yesterday when the question arose  8) ;)

http://forum.arctic-sea-ice.net/index.php/topic,230.msg73244.html#new (http://forum.arctic-sea-ice.net/index.php/topic,230.msg73244.html#new)
Title: Re: 2016 sea ice area and extent data
Post by: charles_oil on April 07, 2016, 11:52:35 AM
NSIDC now seems to have 14.119km2 on the 4th and 14.084 on the 5th - so a drop of .035 - but the image shows a large triangle of undefined.

Maybe it will get sorted in a day or two...

ftp://sidads.colorado.edu/pub/DATASETS/nsidc0081_nrt_nasateam_seaice/browse/north/nt_20160405_f17_nrt_n.png
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on April 07, 2016, 12:35:56 PM
Indeed. Calculation of CT-like area gives now +110k and NSIDC extent -66k5. Since they are both based on the same faulty data, they will both be affected. Some correction will follow today if/when correct data for the next day is processed and used to fill in the gap. Perhaps more data can be restored.

Osi-saf message today says:
Quote
o Message :
The OSI SAF sea ice products are back to nominal production today, after
the missing SSMIS data from NOAA yesterday.

Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on April 08, 2016, 03:16:54 PM
CT SIA has released it's numbers for 0.2631, and, as Wipneus suggested, they are rather odd, showing a one-day increase of 139k, the largest jump since the second week of January, the fifth largest since last November, and--remarkably if not believably, the second largest one-day increase ever recorded in April (which itself was a correction from a one-day "drop" the day before of 396k). So, will there be an offsetting/correcting decrease reflected in the upcoming numbers? Only time will tell, but I'd put money on it...

In other news: IJIS extent has now shown a decrease on 16 of the past 17 days, a rare (if not unheard of) feat so close to the annual maximum...
Title: Re: 2016 sea ice area and extent data
Post by: Buddy on April 08, 2016, 04:09:41 PM

Quote
In other news: IJIS extent has now shown a decrease on 16 of the past 17 days, a rare (if not unheard of) feat so close to the annual maximum...

That is rather "eye popping".  And just one more indication as to how bad of shape the ice is in..... :'(


Title: Re: 2016 sea ice area and extent data
Post by: DavidR on April 08, 2016, 04:38:33 PM
CT SIA has released it's numbers for 0.2631, and, as Wipneus suggested, they are rather odd, showing a one-day increase of 139k, the largest jump since the second week of January, the fifth largest since last November, and--remarkably if not believably, the second largest one-day increase ever recorded in April (which itself was a correction from a one-day "drop" the day before of 396k). So, will there be an offsetting/correcting decrease reflected in the upcoming numbers? Only time will tell, but I'd put money on it...

In other news: IJIS extent has now shown a decrease on 16 of the past 17 days, a rare (if not unheard of) feat so close to the annual maximum...
If you think that  is strange you should see the latest  NSIDC figures which  suggest  an increase  of over 1.000,000 Km ^2. I think it  is time to go and see a good movie and come back on Monday
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on April 08, 2016, 05:09:20 PM
Indeed, my CT-area-like calculation results in an increase of more than 600k and a new maximum of 13.11 Mm2.  That may change still if the data is corrected before CT does its calculation.

Here is my delta image, bright red (blue) indicates the concentration goes below (above) the 15% mark. Pinkish (blueish) colors when the concentration decreases (increases) by more than 7%.

If the SSMIS instrument on the F17 DMSP satellite is failing, are there immediate replacements?
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on April 08, 2016, 05:52:54 PM
In my opinion such obviously false data should not be published in the first place. It looks like nobody is in charge to pull the plug before such data goes online. Having a rest and coming back later is probably the right thing to do. Cheers LOL
Title: Re: 2016 sea ice area and extent data
Post by: Jim Hunt on April 08, 2016, 05:58:47 PM
If the SSMIS instrument on the F17 DMSP satellite is failing, are there immediate replacements?

F-19 is dead already, but F-18 carries SSMIS I believe?
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on April 08, 2016, 06:30:04 PM
CT SIA has released it's numbers for 0.2631, and, as Wipneus suggested, they are rather odd, showing a one-day increase of 139k, the largest jump since the second week of January, the fifth largest since last November, and--remarkably if not believably, the second largest one-day increase ever recorded in April (which itself was a correction from a one-day "drop" the day before of 396k). So, will there be an offsetting/correcting decrease reflected in the upcoming numbers? Only time will tell, but I'd put money on it...

In other news: IJIS extent has now shown a decrease on 16 of the past 17 days, a rare (if not unheard of) feat so close to the annual maximum...
If you think that  is strange you should see the latest  NSIDC figures which  suggest  an increase  of over 1.000,000 Km ^2. I think it  is time to go and see a good movie and come back on Monday

NSIDC graph  ::) :
Title: Re: 2016 sea ice area and extent data
Post by: Tor Bejnar on April 08, 2016, 08:08:21 PM
This NSIDC graph provides "better news" than the graph that showed a one-day virtual melt out.
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fforum.arctic-sea-ice.net%2Findex.php%3Faction%3Ddlattach%3Btopic%3D416.0%3Battach%3D18676%3Bimage&hash=e97ba670f4c1097ebf982b0feca72fc6)
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on April 08, 2016, 09:16:56 PM
BOTHER.  Failing instruments with no clear replacement to provide data.

The results the instrument is providing are obviously flawed.  Just looking at Worldview suggests that to me.

Never a good time for this, but absolutely one of the worst times it could happen.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on April 09, 2016, 04:22:06 PM
ADS-NIPR Extent:
13,237,712 km2 (08 April)
Down 704,795 km2 (5.06%) from 2016 maximum of 13,942,507 km2 on 29 February.
10,060,257 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 71,544 km2 (-.54%) from previous day.
Down 223,544 km2  (-1.66%) over past seven days (daily average: -31,935 km2).
Down 258,488 km2  (-2.11%) for April (daily average: -32,311 km2).
782,989 km2 below 2000s average for this date.
566,792 km2 below 2010s average for this date.
149,318 km2 below 2015 value for this date.
908,238 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 08 April) average.
Lowest April to-date average.
Lowest value for the date.
44 days this year (44.9% year-to-date) have recorded the lowest daily extent.
27 days (27.55%) have recorded the second lowest.
14 days (14.29%) have recorded the third lowest.
85 days in total (86.73%) have been among the lowest three on record.


CT Area:
12,504,183 km2 (08 April [Day 0.2657])
Down 417,175 km2 (3.23%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
10,270,173 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 127,710 km2 (-1.01%) from previous day.
Down 117,257 km2 (-.93%) over past seven days (daily average: -16,751 km2).
Down 154,290 km2 (-1.39%) for April (daily average: -19,286 km2).
705,398 km2 below 2000s average for this date.
498,895 km2 below 2010s average for this date.
255,063 km2 below 2015 value for this date.
658,947 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.2657) average.
Lowest April to-date average.
Lowest value for the date.
59 days this year (60.2% year-to-date) have recorded the lowest daily area.
18 days (18.37%) have recorded the second lowest.
11 days (11.22%) have recorded the third lowest.
88 days in total (89.8%) have been among the lowest three on record.

Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on April 10, 2016, 04:23:12 PM
Problems with the SSMIS data (dmsp f17) continue. In the north the Sea of Okhotsk is showing a lot of false ice. That is peanuts compared with the south, where the CT-area-like calculation is showing a massive bump of +1160k.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on April 10, 2016, 05:43:48 PM
Problems with the SSMIS data (dmsp f17) continue. In the north the Sea of Okhotsk is showing a lot of false ice. That is peanuts compared with the south, where the CT-area-like calculation is showing a massive bump of +1160k.

Maybe it was just really cold yesterday. ;-) I'm not even bothering to update my CT SIA graphs and stats, as the numbers are so screwy. CT says NH ice area has shown 881k movement over the past three days; no sense in disseminating such absurdly incorrect data.

In the meantime, IJIS extent continues its recordbreaking ways, having fallen--in fact, the word "plummeted" is probably warranted given the time of year--18 of the past 19 days for a net loss of 782k, or about 41k per day. IOW, 2016 is--so far, anyway, special.
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on April 10, 2016, 05:49:38 PM
Problems with the SSMIS data (dmsp f17) continue. In the north the Sea of Okhotsk is showing a lot of false ice. That is peanuts compared with the south, where the CT-area-like calculation is showing a massive bump of +1160k.

IJIS:

13,151,679 km2(April 9, 2016)

Quote
"Beaufort under early pressure" from Neven's Blog
http://neven1.typepad.com/blog/2016/04/beaufort-under-early-pressure.html#more (http://neven1.typepad.com/blog/2016/04/beaufort-under-early-pressure.html#more)

It is great to read on this Forum and be aware that the SSMIS data is having problems, so the increase at NSIDC SIE is not real, IJIS is first on record, at the same time that knowing that the Beaufort is under early pressure, so what is true is that the extent is falling.

I want to congratulate the Forum group, for all the work that you have been doing these years.
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on April 10, 2016, 07:03:24 PM
I can only recommend to use these from time to time to verify data and become aware of flawed platforms:

They and more of that kind can be found here: https://sites.google.com/site/arctischepinguin/home/amsr2/grf
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on April 10, 2016, 08:02:54 PM
Looking at IJIS, based on the 4/10's numbers (13151679)

Average loss since 2007 inclusive between this date and mimimum is approximately (rounded to thousands) 9.421 million KM2.  This gives us as a midpoint for 2016's minimum of 3.73 million KM2 - solidly 2nd lowest and flirting with 2012.

There really isn't enough data to produce sensible statistical boundaries (Standard Dev), so instead
 here's what the numbers look like, subtracting annual losses from this date to minimum from IJIS' data, when applied to the current 4/10/2016 SIE.  7 out of 13 years beat 2007, and 3 would put us near or below 2012.

YearLossApplied to current
SIE (4/10/2016)
200383558314795848
200480055425146137
200584552944696385
200676820785469601
200794003773751302
200896437043507975
200989601064191573
201096653343486345
201194313263720353
2012109195462232133
201391848233966856
201487821694369510
201591753273976352
Title: Re: 2016 sea ice area and extent data
Post by: Meirion on April 11, 2016, 10:22:21 AM
jdallen - I've borrowed your numbers and Espen's latest IJIS chart to Tweet (@MeirionTweets) that there is a one in four chance of new record sea ice low in September based on last decade's melts.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on April 11, 2016, 01:21:29 PM
Looking at IJIS, based on the 4/10's numbers (13151679)

Average loss since 2007 inclusive between this date and mimimum is approximately (rounded to thousands) 9.421 million KM2.  This gives us as a midpoint for 2016's minimum of 3.73 million KM2 - solidly 2nd lowest and flirting with 2012.

There really isn't enough data to produce sensible statistical boundaries (Standard Dev), so instead
 here's what the numbers look like, subtracting annual losses from this date to minimum from IJIS' data, when applied to the current 4/10/2016 SIE.  7 out of 13 years beat 2007, and 3 would put us near or below 2012.

YearLossApplied to current
SIE (4/10/2016)
200383558314795848
200480055425146137
200584552944696385
200676820785469601
200794003773751302
200896437043507975
200989601064191573
201096653343486345
201194313263720353
2012109195462232133
201391848233966856
201487821694369510
201591753273976352

FYI, I've long maintained a daily graph (https://sites.google.com/site/pettitclimategraphs/sea-ice-extent#asiepts) helping to visualize these very numbers:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FzXuR6ld.png&hash=86890f73790635665b10d898c418f80b)


Title: Re: 2016 sea ice area and extent data
Post by: Tor Bejnar on April 11, 2016, 04:05:42 PM
Thanks, Jim, for doing so. 

This graph, among many other wonderful graphs, is accessible through Neven's ASI Graphs page (https://sites.google.com/site/arcticseaicegraphs/) - link at the top of this page.  (Several types of graphs [and maps] have their own pages - see the links at the top of the ASI Graphs page.)
Title: Re: 2016 sea ice area and extent data
Post by: DavidR on April 11, 2016, 04:13:50 PM
NSIDC figures show another massive jump today. If we get another massive fall tomorrow it  may  be a message from Batman that he's working on saving the ice.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on April 11, 2016, 04:45:08 PM
Yes, extent up +756k, CT-area +652k. Latest maximum on record.

Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on April 11, 2016, 04:52:25 PM
OSI-SAF are making the switch, latest service message:

Quote
o Message :
Due to the previously reported problems with one of the channels on SSMIS
onboard DMSP F17, OSI SAF is now working on replacing DMSP F17 with DMSP
F18 in our sea ice products.

Currently, the switch to F18 has been implemented for the ice concentration
product (OSI-401). The product dated 20160410 has been reprocessed and is
available on our FTP server, ftp://osisaf.met.no/prod/ice/conc/ (http://ftp://osisaf.met.no/prod/ice/conc/) and
ftp://osisaf.met.no/archive/ice/conc/2016/04 (http://ftp://osisaf.met.no/archive/ice/conc/2016/04)

The ice edge and type products (OSI-402 and OSI-403) will be updated to use
F18 tomorrow, 2016-04-12.

The ice emissivity product (OSI-404) has been temporary turned off.
Production will be upgraded to F18, with expected implementation 19th
April.

The LR ice drift product (OSI-405) does not use the channel with
calibration problems, but is affected to some extent since it uses the ice
edge product to define areas with ice. This product will be back to nominal
as soon as the ice edge product is updated.

o Comments or Extra information :
We are sorry for the inconvenience these problems might have caused. We
will report on the quality of the products with the new sensor as soon as
more data are available.
More information on www.osi-saf.org (http://www.osi-saf.org)
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on April 12, 2016, 05:31:14 AM
FYI, I've long maintained a daily graph (https://sites.google.com/site/pettitclimategraphs/sea-ice-extent#asiepts) helping to visualize these very numbers:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FzXuR6ld.png&hash=86890f73790635665b10d898c418f80b)
Sorry, Jim, not meaning to undermine your contribution.  Just stating possible end points.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on April 16, 2016, 02:13:05 PM
ADS-NIPR Extent:
13,134,117 km2 (15 April)
Down 808,390 km2 (5.8%) from 2016 maximum of 13,942,507 km2 on 29 February.
9,956,662 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 23,553 km2 (-.18%) from previous day.
Down 103,595 km2  (-.78%) over past seven days (daily average: -14,799 km2).
Down 362,083 km2  (-2.96%) for April (daily average: -24,139 km2).
586,567 km2 below 2000s average for this date.
477,945 km2 below 2010s average for this date.
221,042 km2 below 2015 value for this date.
916,413 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 15 April) average.
Lowest April to-date average.
Lowest value for the date.
51 days this year (48.57% year-to-date) have recorded the lowest daily extent.
27 days (25.71%) have recorded the second lowest.
14 days (13.33%) have recorded the third lowest.
92 days in total (87.62%) have been among the lowest three on record.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on April 19, 2016, 12:59:14 PM
ADS-NIPR Extent:
12,996,593 km2 (18 April)
NOTE: Earliest sub-13 million km2 reading on record.
Down 945,914 km2 (6.78%) from 2016 maximum of 13,942,507 km2 on 29 February.
9,819,138 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 62,543 km2 (-.48%) from previous day.
Down 122,288 km2  (-.93%) over past seven days (daily average: -17,470 km2).
Down 499,607 km2  (-4.08%) for April (daily average: -27,756 km2).
607,644 km2 below 2000s average for this date.
498,748 km2 below 2010s average for this date.
347,023 km2 below 2015 value for this date.
967,833 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 18 April) average.
Lowest April to-date average.
Lowest value for the date.
54 days this year (50% year-to-date) have recorded the lowest daily extent.
27 days (25%) have recorded the second lowest.
14 days (12.96%) have recorded the third lowest.
95 days in total (87.96%) have been among the lowest three on record.
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on April 19, 2016, 03:10:56 PM
ADS-NIPR Extent:
<<< snippage >>>
967,833 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 18 April) average.
<<< snippage >>>
95 days in total (87.96%) have been among the lowest three on record.
Worth noting, between now and minimum in 2012, the Arctic shed 10.78 million KM2 of ice.
Title: Re: 2016 sea ice area and extent data
Post by: AmbiValent on April 19, 2016, 03:22:10 PM
The CT area anomaly seems to have gone back to pre-hiccup levels. Is there any indication when CT area accuracy will be completely repaired?
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on April 19, 2016, 04:16:17 PM
The CT area anomaly seems to have gone back to pre-hiccup levels. Is there any indication when CT area accuracy will be completely repaired?

CT area is derived from NSIDC concentration, same as NSIDC's own sea ice index (extent).

Problems seem to be much reduced for the last couple of days. In the latest data, released yesterday, only in the Japanese and Yellow Seas there is some pattern of suspicious ice. On the other hand there may be other problems there ( bad weather) having nothing to do with the sensor failure.

We will have to wait until NSIDC completes their investigation.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on April 20, 2016, 02:04:48 PM
NSIDC confirms that the situation has improved/restored (hat tip to Michael Yorke ):

Quote
Notice (04/05/2016): Notice (04/19/2016): Daily sea ice concentration updates have improved. On 04/05/2016 a change in the solar panel position to shade the nitrogen tank on board the Defense Meteorological Satellite Program (DMSP) F-17 satellite was made. In doing so, the integrity of the vertically polarized 37 GHz channel (37V) of the Special Sensor Microwave Imager and Sounder (SSMIS) was compromised. This is a primary channel used in the sea ice processing. On 04/13/16 an additional change in the solar panel position was made.This change has improved the problems we were seeing in the 37V GHz channel. The affected daily files from 04/05 – 04/13 have been removed from distribution.

(Colored by NSIDC ).

https://nsidc.org/data/nsidc-0081
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on April 20, 2016, 02:24:10 PM
NSIDC confirms that the situation has improved/restored (hat tip to Michael Yorke ):

Quote
Notice (04/05/2016): Notice (04/19/2016): Daily sea ice concentration updates have improved. On 04/05/2016 a change in the solar panel position to shade the nitrogen tank on board the Defense Meteorological Satellite Program (DMSP) F-17 satellite was made. In doing so, the integrity of the vertically polarized 37 GHz channel (37V) of the Special Sensor Microwave Imager and Sounder (SSMIS) was compromised. This is a primary channel used in the sea ice processing. On 04/13/16 an additional change in the solar panel position was made.This change has improved the problems we were seeing in the 37V GHz channel. The affected daily files from 04/05 – 04/13 have been removed from distribution.

(Colored by NSIDC ).

https://nsidc.org/data/nsidc-0081

That's great news. Now, will CT also remove their SIA data from 04/05 - 04/13? Or, more accurately, 04/07 through 04/15?
Title: Re: 2016 sea ice area and extent data
Post by: Neven on April 20, 2016, 02:37:06 PM
This is great! I thought the sensor had failed, but apparently it was because of that solar panel.
Title: Re: 2016 sea ice area and extent data
Post by: TerryM on April 20, 2016, 05:02:29 PM
From Jim Pettit's outstanding SIA chart, it seems as though it's never taken more than 26 days to blow through the 11M ice, and in many years 13 days sufficed. We are starting far earlier than in the past so the sun will be at a lower angel and we'll have less insolation than in the past. It is however approximately the same regions of ice that will be melting.
DMI shows that north of 80 has still never cooled off to 'normal' levels. 110 days of April like weather since Jan 1. If this softer, warmer, more mobile ice melts as rapidly as it has in past years we could be in for a record setting September.


Terry
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on April 21, 2016, 02:23:13 PM
ADS-NIPR Extent:
12,877,955 km2 (20 April)
Down 1,064,552 km2 (7.64%) from 2016 maximum of 13,942,507 km2 on 29 February.
9,700,500 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 50,162 km2 (-.39%) from previous day.
Down 301,885 km2  (-2.29%) over past seven days (daily average: -43,126 km2).
Down 618,245 km2  (-5.05%) for April (daily average: -30,912 km2).
677,457 km2 below 2000s average for this date.
545,834 km2 below 2010s average for this date.
415,001 km2 below 2015 value for this date.
1,054,059 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 20 April) average.
Lowest April to-date average.
Lowest value for the date.
56 days this year (50.91% year-to-date) have recorded the lowest daily extent.
27 days (24.55%) have recorded the second lowest.
14 days (12.73%) have recorded the third lowest.
97 days in total (88.18%) have been among the lowest three on record.


CT Area:
12,125,451 km2 (20 April [Day 0.2986])
Down 795,907 km2 (6.16%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
9,891,442 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 75,161 km2 (-.62%) from previous day.
Down 276,489 km2 (-2.48%) for April (daily average: -13,824 km2).
523,272 km2 below 2000s average for this date.
450,561 km2 below 2010s average for this date.
400,946 km2 below 2015 value for this date.
888,195 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.2986) average.
Lowest April to-date average.
Lowest value for the date.
61 days this year (60.4% year-to-date) have recorded the lowest daily area.
19 days (18.81%) have recorded the second lowest.
11 days (10.89%) have recorded the third lowest.
91 days in total (90.1%) have been among the lowest three on record.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on April 22, 2016, 07:55:15 AM
The problems have resurfaced again:

Quote
Notice (04/21/2016): On 04/05/2016 a change in the solar panel position to shade the nitrogen tank on board the Defense Meteorological Satellite Program (DMSP) F-17 satellite was made. In doing so, the integrity of the vertically polarized 37 GHz channel (37V) of the Special Sensor Microwave Imager and Sounder (SSMIS) was compromised. On 04/13/16 an additional change in the solar panel position was made. This change had improved the problems we were seeing in the 37V GHz channel for data from April 13 to April 19; however, on April 20, the 37V GHz channel started to produce bad data again. Thus, data from April 20 onward should not be used until further notice. The affected daily files from 04/05 – 04/13 have been removed from distribution.

(color by NSIDC)

Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on April 22, 2016, 02:44:05 PM
Assuming the -128k drop in CT SIA stands--and there's no reason it shouldn't--2016 area fell below 12 million the earliest it ever has. In fact, this year's SIA fell below 12 million on the same day--0.3014--that 2012 fell below 13 million. Of course, one of the things that helped 2012 break the record was losing more than 1 million km2 over the next two weeks; it will be Very Interesting to see whether this year can maintain its huge lead...

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FQczEJih.png&hash=93f4642e7587c6f2efb460c33fc4a024)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on April 23, 2016, 02:27:33 PM
CT SIA's numbers are way off again today, showing a one-day increase of 1.387 million km2, and setting a new annual maximum nearly 400k higher than what it was.

Sigh...

Oh well, at least we got six days of accurate and usable  numbers in the past two-and-a-half weeks. I think.  ::)

In the meantime:

ADS-NIPR Extent:
12,747,752 km2 (22 April)
Down 1,194,755 km2 (8.57%) from 2016 maximum of 13,942,507 km2 on 29 February.
9,570,297 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 89,382 km2 (-.7%) from previous day.
Down 386,365 km2  (-2.94%) over past seven days (daily average: -55,195 km2).
Down 748,448 km2  (-6.12%) for April (daily average: -34,020 km2).
745,950 km2 below 2000s average for this date.
624,417 km2 below 2010s average for this date.
554,843 km2 below 2015 value for this date.
1,102,009 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 22 April) average.
Lowest April to-date average.
Lowest value for the date.
58 days this year (51.79% year-to-date) have recorded the lowest daily extent.
27 days (24.11%) have recorded the second lowest.
14 days (12.5%) have recorded the third lowest.
99 days in total (88.39%) have been among the lowest three on record.
Title: Re: 2016 sea ice area and extent data
Post by: Tor Bejnar on April 23, 2016, 04:48:58 PM
CT SIA's numbers are ... setting a new annual maximum nearly 400k higher than what it was.
...
That's the best news I've heard all year!   ;D
(Because this didn't actually happen, I need to go for a walk by the sea or in a forest or through a desert, and breathe.  Heck, we should all do that!)
Title: Re: 2016 sea ice area and extent data
Post by: Buddy on April 23, 2016, 10:58:45 PM
Quote
1,102,009 km2 below 2012 value for this date.

Frigging incredible....... :o
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on April 25, 2016, 04:21:57 PM
ADS-NIPR Extent:
12,633,672 km2 (24 April)
Down 1,308,835 km2 (9.39%) from 2016 maximum of 13,942,507 km2 on 29 February.
9,456,217 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 48,001 km2 (-.38%) from previous day.
Down 425,464 km2  (-3.26%) over past seven days (daily average: -60,781 km2).
Down 862,528 km2  (-7.05%) for April (daily average: -35,939 km2).
768,978 km2 below 2000s average for this date.
619,682 km2 below 2010s average for this date.
476,522 km2 below 2015 value for this date.
1,033,249 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 24 April) average.
Lowest April to-date average.
Lowest value for the date.
60 days this year (52.63% year-to-date) have recorded the lowest daily extent.
27 days (23.68%) have recorded the second lowest.
14 days (12.28%) have recorded the third lowest.
101 days in total (88.6%) have been among the lowest three on record.


CT Area:
11,817,238 km2 (24 April [Day 0.3096])
Down 1,104,120 km2 (8.54%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
9,583,228 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
724,800 km2 below 2000s average for this date.
600,173 km2 below 2010s average for this date.
513,767 km2 below 2015 value for this date.
1,113,250 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.3096) average.
Lowest April to-date average.
Lowest value for the date.
63 days this year (61.17% year-to-date) have recorded the lowest daily area.
19 days (18.45%) have recorded the second lowest.
11 days (10.68%) have recorded the third lowest.
93 days in total (90.29%) have been among the lowest three on record.



Title: Re: 2016 sea ice area and extent data
Post by: jdallen on April 25, 2016, 06:53:23 PM
CT Area:
11,817,238 km2 (24 April [Day 0.3096])
Down 1,104,120 km2 (8.54%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
9,583,228 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
724,800 km2 below 2000s average for this date.
600,173 km2 below 2010s average for this date.
513,767 km2 below 2015 value for this date.
1,113,250 km2 below 2012 value for this date.
If this year follows 2012's trajectory, we would be within a couple 100,000KM2 of dropping under 2 million KM2 extent and 1 million KM2 of area.

Letting that sink in now.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on April 25, 2016, 07:37:06 PM
CT Area:
11,817,238 km2 (24 April [Day 0.3096])
Down 1,104,120 km2 (8.54%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
9,583,228 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
724,800 km2 below 2000s average for this date.
600,173 km2 below 2010s average for this date.
513,767 km2 below 2015 value for this date.
1,113,250 km2 below 2012 value for this date.
If this year follows 2012's trajectory, we would be within a couple 100,000KM2 of dropping under 2 million KM2 extent and 1 million KM2 of area.

Letting that sink in now.

Correct. More precisely, were the rest of 2016's melt season to follow 2012 exactly, this year would sea a mid-September low of 1,120,760 km2.
Title: Re: 2016 sea ice area and extent data
Post by: Phil. on April 25, 2016, 07:53:02 PM
Assuming the -128k drop in CT SIA stands--and there's no reason it shouldn't--2016 area fell below 12 million the earliest it ever has. In fact, this year's SIA fell below 12 million on the same day--0.3014--that 2012 fell below 13 million. Of course, one of the things that helped 2012 break the record was losing more than 1 million km2 over the next two weeks; it will be Very Interesting to see whether this year can maintain its huge lead...


Looks pretty close to the timing in 2007?
Title: Re: 2016 sea ice area and extent data
Post by: Neven on April 25, 2016, 08:09:12 PM
test

(https://ads.nipr.ac.jp/vishop/data/graph/Sea_Ice_Extent_N_v2_L.png)
Title: Re: 2016 sea ice area and extent data
Post by: Neven on April 25, 2016, 08:15:23 PM
It's strange. That ADS-NIPR JAXA SIE graph no longer appears on the front page of the ASIG, but I haven't changed anything and all the HTML is as it's supposed to be. As you can see in the comment above I can link to the image and it shows up.

Does anyone have a clue why this is? Given that the JAXA graph is one of the few that is still working properly, I'd really like to have it back on the ASIG.
Title: Re: 2016 sea ice area and extent data
Post by: crandles on April 25, 2016, 08:17:18 PM
It's strange. That ADS-NIPR JAXA SIE graph no longer appears on the front page of the ASIG, but I haven't changed anything and all the HTML is as it's supposed to be. As you can see in the comment above I can link to the image and it shows up.

Does anyone have a clue why this is? Given that the JAXA graph is one of the few that is still working properly, I'd really like to have it back on the ASIG.

Displaying on graphs page for me. (As well as here 2 posts above.)
Title: Re: 2016 sea ice area and extent data
Post by: Neven on April 25, 2016, 08:23:50 PM
Displaying on graphs page for me. (As well as here 2 posts above.)

Really? That's good, as it means that probably most people can see it.

But why just me?  :'( ;)

It's not a browser issue, as both Chrome and Firefox aren't showing it for me. Could it be an IP issue and the Japanese have banned me because I accessed the image too often? I'm going to try and check that now (using VPN).
Title: Re: 2016 sea ice area and extent data
Post by: doogi on April 25, 2016, 09:16:22 PM
Displaying on graphs page for me. (As well as here 2 posts above.)

Really? That's good, as it means that probably most people can see it.

But why just me?  :'( ;)

It's not a browser issue, as both Chrome and Firefox aren't showing it for me. Could it be an IP issue and the Japanese have banned me because I accessed the image too often? I'm going to try and check that now (using VPN).

I can't see it, neither here or on ASIG.
I do however se it if i take the url in your post #169 (wich i can see when i press quote) and paste it in a new window.


Edit:
I belive it's an adblock issue, everything works fine when i disable adblock.
Title: Re: 2016 sea ice area and extent data
Post by: Neven on April 25, 2016, 09:47:28 PM
This must be the annual 'Neven thinks there's something wrong, but it's just his bloody Adblocker'-moment. I think this is the third time now this has happened to me. And I'm only 42.

Thanks, doogi! That did the trick!
Title: Re: 2016 sea ice area and extent data
Post by: OldLeatherneck on April 26, 2016, 02:25:54 AM
This must be the annual 'Neven thinks there's something wrong, but it's just his bloody Adblocker'-moment. I think this is the third time now this has happened to me. And I'm only 42.

Thanks, doogi! That did the trick!

Wait until you age another 30 years.  I'm finding that adapting to new technologies is more threatening than Climate  Change, Donald  Trump, Ted Cruz, Kim Jung Un and ISIS all combined.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on April 26, 2016, 06:00:40 PM
DMSP F17 troubles are still there (nearly a millennium jump in extent today). OSI-SAF reports that the changeover to the F18 is now complete including reprocessing of the sea ice concentration product.

Quote
The OSI SAF continuous reprocessed sea ice concentration offline product
(OSI-430) is back to nominal production and distribution, now with SSMIS
data from DMSP F18. Production has been rerun with SSMIS F18 data to cover
the missing dates since 13th April, and all data are available on our ftp
server ftp://osisaf.met.no/reprocessed/ice/conc-cont-reproc/v1p2/2016/03/

Title: Re: 2016 sea ice area and extent data
Post by: sedziobs on April 26, 2016, 06:22:35 PM
DMSP F17 troubles are still there (nearly a millennium jump in extent today). OSI-SAF reports that the changeover to the F18 is now complete including reprocessing of the sea ice concentration product.

According to Robert Grumbine, there are some issues with F18.  He notes that the satellite instruments are designed for a 5 year lifespan, which both the F-17 and F-18 have already exceeded.  In a summary of all the satellites he says:
Quote
F-17 is/was widely used, so many places are having difficulty.  F-18 has a very bad channel at 150 GHz, but the other imaging channels seem to be ok.  F-19 should be the best of the group, being the youngest, but quit providing data.
Quote
F-18: Mostly ok, but reduced volume of data.  Many orbits' data not making it through.
http://moregrumbinescience.blogspot.com/2016/04/2016-tough-on-sea-ice-satellites.html (http://moregrumbinescience.blogspot.com/2016/04/2016-tough-on-sea-ice-satellites.html)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on April 29, 2016, 02:12:35 PM
ADS-NIPR Extent:
12,413,834 km2 (28 April)
Down 1,528,673 km2 (10.96%) from 2016 maximum of 13,942,507 km2 on 29 February.
9,236,379 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 85,164 km2 (-.68%) from previous day.
Down 423,300 km2  (-3.3%) over past seven days (daily average: -60,471 km2).
Down 1,082,366 km2  (-8.85%) for April (daily average: -38,656 km2).
811,314 km2 below 2000s average for this date.
580,259 km2 below 2010s average for this date.
401,936 km2 below 2015 value for this date.
876,780 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 28 April) average.
Lowest April to-date average.
Lowest value for the date.
64 days this year (54.24% year-to-date) have recorded the lowest daily extent.
27 days (22.88%) have recorded the second lowest.
14 days (11.86%) have recorded the third lowest.
105 days in total (88.98%) have been among the lowest three on record.


CT Area:
11,547,403 km2 (28 April [Day 0.3206])
Down 1,373,955 km2 (10.63%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
9,313,394 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 502,439 km2 (-4.51%) for April (daily average: -17,944 km2).
795,909 km2 below 2000s average for this date.
587,385 km2 below 2010s average for this date.
437,383 km2 below 2015 value for this date.
1,103,418 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.3206) average.
Lowest April to-date average.
Lowest value for the date.
66 days this year (62.26% year-to-date) have recorded the lowest daily area.
19 days (17.92%) have recorded the second lowest.
11 days (10.38%) have recorded the third lowest.
96 days in total (90.57%) have been among the lowest three on record.

Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 03, 2016, 02:23:00 PM
ADS-NIPR Extent:
12,164,312 km2 (02 May)
Down 1,778,195 km2 (12.75%) from 2016 maximum of 13,942,507 km2 on 29 February.
8,986,857 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 31,101 km2 (-.26%) from previous day.
Down 431,506 km2  (-3.43%) over past seven days (daily average: -61,644 km2).
Down 129,135 km2  (-1.06%) for May (daily average: -64,568 km2).
895,110 km2 below 2000s average for this date.
606,596 km2 below 2010s average for this date.
470,584 km2 below 2015 value for this date.
849,792 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 02 May) average.
Lowest May to-date average.
Lowest value for the date.
68 days this year (55.74% year-to-date) have recorded the lowest daily extent.
27 days (22.13%) have recorded the second lowest.
14 days (11.48%) have recorded the third lowest.
109 days in total (89.34%) have been among the lowest three on record.


CT Area:
11,320,857 km2 (02 May [Day 0.3315])
Down 1,600,501 km2 (12.39%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
9,086,848 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
866,183 km2 below 2000s average for this date.
578,520 km2 below 2010s average for this date.
676,849 km2 below 2015 value for this date.
875,744 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.3315) average.
Lowest May to-date average.
Lowest value for the date.
At least 67* days this year have recorded the lowest daily area.
At least 19* days have recorded the second lowest.
At least 11* days have recorded the third lowest.
At least 97* days in total have been among the lowest three on record.
* - Multiple days in the Cryosphere Today 2016 data are missing and/or invalid; for that reason, they are not represented in these sums.
Title: Re: 2016 sea ice area and extent data
Post by: cartographer on May 03, 2016, 04:25:10 PM
ADS-NIPR Extent:
109 days in total (89.34%) have been among the lowest three on record.


CT Area:
97 days in total (90.65%) have been among the lowest three on record.

Thanks for these updates. I am just curious about the different number of days between these two data sets. Do you only have CT Area info for a subset of the year, so those 97 days constitutes a greater percentage (90.65%) of the recorded days, vs the 109 days of the Extent data (which only come up to 89.34%)?

Thanks
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 03, 2016, 05:10:59 PM
ADS-NIPR Extent:
109 days in total (89.34%) have been among the lowest three on record.


CT Area:
97 days in total (90.65%) have been among the lowest three on record.

Thanks for these updates. I am just curious about the different number of days between these two data sets. Do you only have CT Area info for a subset of the year, so those 97 days constitutes a greater percentage (90.65%) of the recorded days, vs the 109 days of the Extent data (which only come up to 89.34%)?

Thanks

Thanks. Note the edits to the previous post.
Title: Re: 2016 sea ice area and extent data
Post by: Tor Bejnar on May 03, 2016, 05:33:56 PM
Quote
Note the edits to the previous post.
Thanks, Jim, for the explanation.
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on May 03, 2016, 05:42:56 PM

Thanks for these updates. I am just curious about the different number of days between these two data sets.

hehe... thought the same days ago but was afraid to ask, thought i just missed an important point that would be obvious :-) thanks for asking and

thanks @Jim Pettit for the prompt and accurate explanation  8)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 04, 2016, 08:39:17 AM
From NSIDC data announcements, it will take a minimum of two months (http://nsidc.org/the-drift/data-update/sea-ice-index-processing-suspended/) until sea ice concentration and sea ice index will be updating regularly again:

Quote
Sea Ice Index Processing Suspended
May 3, 2016   

The Sea Ice Index is typically updated every day to display yesterday’s ice extent for both hemispheres. The Index relies on data that come from the DMSP F17 satellite. However, these data have not been reliable since early April; so the NOAA@NSIDC team has not been able to update the Sea Ice Index since 31 March 2016.

Sea Ice Index processing uses an NSIDC NASA DAAC product, Near-Real-Time DMSP SSMIS Daily Polar Gridded Sea Ice Concentrations (NSIDC-0081), as input. The NSIDC DAAC has started the work needed to move to a new source for NSIDC-0081. This involves retrieving F18 and F16 satellite brightness temperatures from our data providers and then implementing parallel processing for ice concentration to determine which satellite will be best suited to continue the time series. The satellite selected will be the primary replacement for F17, but should that satellite fail, we will be able to switch to the other one without a service interruption.

An interim version of the NSIDC-0081 data stream will be used for the ASINA product, which is based on the Sea Ice Index, to continue to report on sea ice conditions. However, the Sea Ice Index processing itself will not resume until a version of NSIDC-0081 is available that is vetted by the science team. It is not known how long this will take, but we expect it will be a minimum of two months before NSIDC-0081 is updating regularly again with a new vetted source and the Sea Ice Index is processing that new input.

Users may want to explore daily arctic-wide ice extent from the NIC/NSIDC MASIE product as an alternative product for the Northern Hemisphere. The MASIE ice extent record is not consistent with that from the Sea Ice Index, however, nor is it necessarily internally consistent. See the MASIE documentation in order to gain a better understanding of how the product is created.
Title: Re: 2016 sea ice area and extent data
Post by: abbottisgone on May 04, 2016, 10:30:29 AM

Thanks for these updates. I am just curious about the different number of days between these two data sets.

hehe... thought the same days ago but was afraid to ask, thought i just missed an important point that would be obvious :-) thanks for asking and

thanks @Jim Pettit for the prompt and accurate explanation  8)
Malcolm Turnbulls gonna love that !!
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 04, 2016, 02:13:07 PM
From NSIDC data announcements, it will take a minimum of two months (http://nsidc.org/the-drift/data-update/sea-ice-index-processing-suspended/) until sea ice concentration and sea ice index will be updating regularly again:

Quote
Sea Ice Index Processing Suspended
May 3, 2016   

The Sea Ice Index is typically updated every day to display yesterday’s ice extent for both hemispheres. The Index relies on data that come from the DMSP F17 satellite. However, these data have not been reliable since early April; so the NOAA@NSIDC team has not been able to update the Sea Ice Index since 31 March 2016.

Sea Ice Index processing uses an NSIDC NASA DAAC product, Near-Real-Time DMSP SSMIS Daily Polar Gridded Sea Ice Concentrations (NSIDC-0081), as input. The NSIDC DAAC has started the work needed to move to a new source for NSIDC-0081. This involves retrieving F18 and F16 satellite brightness temperatures from our data providers and then implementing parallel processing for ice concentration to determine which satellite will be best suited to continue the time series. The satellite selected will be the primary replacement for F17, but should that satellite fail, we will be able to switch to the other one without a service interruption.

An interim version of the NSIDC-0081 data stream will be used for the ASINA product, which is based on the Sea Ice Index, to continue to report on sea ice conditions. However, the Sea Ice Index processing itself will not resume until a version of NSIDC-0081 is available that is vetted by the science team. It is not known how long this will take, but we expect it will be a minimum of two months before NSIDC-0081 is updating regularly again with a new vetted source and the Sea Ice Index is processing that new input.

Users may want to explore daily arctic-wide ice extent from the NIC/NSIDC MASIE product as an alternative product for the Northern Hemisphere. The MASIE ice extent record is not consistent with that from the Sea Ice Index, however, nor is it necessarily internally consistent. See the MASIE documentation in order to gain a better understanding of how the product is created.

Alright then. Thanks for that basketful of bad but not altogether unexpected news. Now, the press release stated it would be "a minimum of two months" before things are stabilized. So, pessimistically-speaking, we could possibly lose most--or even all--of the melt season?

Awesome... :\
Title: Re: 2016 sea ice area and extent data
Post by: crandles on May 04, 2016, 03:26:02 PM
If it is going to be 2 months perhaps we should try to get a list of products and the extent to which each is affected.

E.g. is Cryosphere area reliable? (seems like a few days affected but many OK? Or shouldn't we trust any data since early April?)
PIOMAS ??
MASIE - presume unaffected from that announcement.
Ads / NIPR (IJIS) - appears unaffected?
Uni Bremen AMSR2 - appears unaffected?
DMI Volume - appears unaffected?
DMI Extent - appears unaffected?
IMS - appears unaffected?

NSIDC Extent - data ceased til ~July
NORSEX SSM  - data ceased

Perhaps there are better ways of doing it or more useful data could be displayed like what satellite services each product uses so that if/when there is a future problem we can see which products will be affected. A separate thread with first post updated?
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 05, 2016, 02:32:11 PM
ADS-NIPR Extent:
12,081,393 km2 (04 May)
Down 1,861,114 km2 (13.35%) from 2016 maximum of 13,942,507 km2 on 29 February.
8,903,938 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 63,054 km2 (-.52%) from previous day.
Down 417,605 km2  (-3.34%) over past seven days (daily average: -59,658 km2).
Down 212,054 km2  (-1.73%) for May (daily average: -53,014 km2).
881,220 km2 below 2000s average for this date.
592,392 km2 below 2010s average for this date.
507,605 km2 below 2015 value for this date.
816,381 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 04 May) average.
Lowest May to-date average.
Lowest value for the date.
70 days this year (56.45% year-to-date) have recorded the lowest daily extent.
27 days (21.77%) have recorded the second lowest.
14 days (11.29%) have recorded the third lowest.
111 days in total (89.52%) have been among the lowest three on record.


CT Area:
11,021,056 km2 (04 May [Day 0.337])
NOTE: the sea ice area data shown here may be inaccurate and subject to change or deletion. Use at your own risk.
Down 1,900,302 km2 (14.71%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
8,787,047 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 115,006 km2 (-1.03%) from previous day.
994,026 km2 below 2000s average for this date.
661,057 km2 below 2010s average for this date.
812,250 km2 below 2015 value for this date.
979,720 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.337) average.
Lowest May to-date average.
Lowest value for the date.
At least 69* days this year have recorded the lowest daily area.
At least 19* days have recorded the second lowest.
At least 11* days have recorded the third lowest.
At least 99* days in total have been among the lowest three on record.
* -Multiple days in the Cryosphere Today 2016 data are missing and/or invalid; for that reason, they are not represented in these sums.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 06, 2016, 09:31:07 AM
It is official:

Quote
Dear colleague,

The Sea Ice Index has suspended processing due to unreliable input data. Sea Ice Index processing uses a NSIDC NASA DAAC product, Near-Real-Time DMSP SSMIS Daily Polar Gridded Sea Ice Concentrations (NSIDC-0081), as input. The NSIDC-0081 product utilizes data from the 37V channel of the DMSP F-17 satellite which is producing unreliable data. The last date available is 31 March 2016.

The NSIDC DAAC has started the work needed to move to a new data source for NSIDC-0081. An interim version of the NSIDC-0081 data stream will be available with the new data source, however Sea Ice Index processing will not resume until a calibrated version of NSIDC-0081 is available. For more information please see http://nsidc.org/the-drift/data-update/sea-ice-index-processing-suspended/ (http://nsidc.org/the-drift/data-update/sea-ice-index-processing-suspended/)

Access to the data and documentation is provided on the Sea Ice Index web site at: https://nsidc.org/data/seaice_index/ (https://nsidc.org/data/seaice_index/)

If you have questions, please contact NSIDC's User Services Office at nsidc@nsidc.org

Data Acknowledgements
Data authors: Fetterer, F., K. Knowles, W. Meier, and M. Savoie
Data set DOI:http://dx.doi.org/10.7265/N5QJ7F7W
Data center: NOAA@NSIDC (http://nsidc.org/noaa/ (http://nsidc.org/noaa/))
Sponsor: NOAA/NESDIS/NGDC and the NOAA Arctic Research Program

Best regards,
NSIDC User Services

See also:
http://nsidc.org/the-drift/data-update/nsidc-halts-production-of-the-near-real-time-dmsp-ssmis-daily-polar-gridded-sea-ice-concentrations-f17-data/ (http://nsidc.org/the-drift/data-update/nsidc-halts-production-of-the-near-real-time-dmsp-ssmis-daily-polar-gridded-sea-ice-concentrations-f17-data/)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 06, 2016, 09:38:53 AM
The mentioned uncalibrated F18 based sea ice concentration is available now (from first of April).

I have changed my programs to make use of the new data source (and ignoring any F17 data since 1st of April). The graphs and data files have been updated accordingly.

Attached is the latest delta map.
Title: Re: 2016 sea ice area and extent data
Post by: Buddy on May 06, 2016, 01:21:26 PM
CT Area:
 
11,021,056 km2 (04 May [Day 0.337])
NOTE: the sea ice area data shown here may be inaccurate and subject to change or deletion.
Quote
Use at your own risk.
Down 1,900,302 km2 (14.71%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
8,787,047 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
 
Down 115,006 km2 (-1.03%) from previous day.
994,026 km2 below 2000s average for this date.
661,057 km2 below 2010s average for this date.
812,250 km2 below 2015 value for this date.
979,720 km2 below 2012 value for this date.

Part of Jim's data is above.

For those wanting a "visual idea".  That 812,250 km2 is just under TWICE THE SIZE OF TEXAS.  That's....a LOT.

Title: Re: 2016 sea ice area and extent data
Post by: DavidR on May 06, 2016, 03:28:58 PM
CT Area:
 
11,021,056 km2 (04 May [Day 0.337])
NOTE: the sea ice area data shown here may be inaccurate and subject to change or deletion.
Quote
Use at your own risk.
Down 1,900,302 km2 (14.71%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
8,787,047 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
 
Down 115,006 km2 (-1.03%) from previous day.
994,026 km2 below 2000s average for this date.
661,057 km2 below 2010s average for this date.
812,250 km2 below 2015 value for this date.
979,720 km2 below 2012 value for this date.

Part of Jim's data is above.

For those wanting a "visual idea".  That 812,250 km2 is just under TWICE THE SIZE OF TEXAS.  That's....a LOT.
On behalf of New Scientists' Feedback page can I  ask how big is that in Elephant Hides ;D
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 06, 2016, 04:10:03 PM
CT Area:
 
11,021,056 km2 (04 May [Day 0.337])
NOTE: the sea ice area data shown here may be inaccurate and subject to change or deletion.
Quote
Use at your own risk.
Down 1,900,302 km2 (14.71%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
8,787,047 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
 
Down 115,006 km2 (-1.03%) from previous day.
994,026 km2 below 2000s average for this date.
661,057 km2 below 2010s average for this date.
812,250 km2 below 2015 value for this date.
979,720 km2 below 2012 value for this date.

Part of Jim's data is above.

For those wanting a "visual idea".  That 812,250 km2 is just under TWICE THE SIZE OF TEXAS.  That's....a LOT.
On behalf of New Scientists' Feedback page can I  ask how big is that in Elephant Hides ;D

Using the formula S = -8.245 + 6.807H + 7.073FFC
(Estimation of the total surface area in Indian elephants (Elephas maximus indicus) Sreekumar / Nirmalan et al (http://www.ncbi.nlm.nih.gov/pubmed/2316192)), it's calculated that an average pachyderm has a surface area of about 20 square meters. Thus, (812,250 km2 / 1,000,000) / 20 = 40,612,500,000, or 40.6125 billion elephants.
Title: Re: 2016 sea ice area and extent data
Post by: Robert Greer on May 06, 2016, 04:11:13 PM
812,000 km2 is about 20% bigger than Texas. But it's still a hell of a lot -- very nearly twice the size of California.
Title: Re: 2016 sea ice area and extent data
Post by: Buddy on May 06, 2016, 04:42:35 PM


Quote
812,000 km2 is about 20% bigger than Texas. But it's still a hell of a lot -- very nearly twice the size of California.

"User error" when inputting the numbers.  I HATE THAT when that happens.  Good catch, my bad...thanks

And yes...it is still "big"...


Title: Re: 2016 sea ice area and extent data
Post by: Shared Humanity on May 06, 2016, 11:07:28 PM
CT Area:
 
11,021,056 km2 (04 May [Day 0.337])
NOTE: the sea ice area data shown here may be inaccurate and subject to change or deletion.
Quote
Use at your own risk.
Down 1,900,302 km2 (14.71%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
8,787,047 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
 
Down 115,006 km2 (-1.03%) from previous day.
994,026 km2 below 2000s average for this date.
661,057 km2 below 2010s average for this date.
812,250 km2 below 2015 value for this date.
979,720 km2 below 2012 value for this date.

Part of Jim's data is above.

For those wanting a "visual idea".  That 812,250 km2 is just under TWICE THE SIZE OF TEXAS.  That's....a LOT.
On behalf of New Scientists' Feedback page can I  ask how big is that in Elephant Hides ;D

Using the formula S = -8.245 + 6.807H + 7.073FFC
(Estimation of the total surface area in Indian elephants (Elephas maximus indicus) Sreekumar / Nirmalan et al (http://www.ncbi.nlm.nih.gov/pubmed/2316192)), it's calculated that an average pachyderm has a surface area of about 20 square meters. Thus, (812,250 km2 / 1,000,000) / 20 = 40,612,500,000, or 40.6125 billion elephants.

Oh sure. You use the smaller Indian elephant to exaggerate the problem.  >:(
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 07, 2016, 12:35:40 AM
CT Area:
 
11,021,056 km2 (04 May [Day 0.337])
NOTE: the sea ice area data shown here may be inaccurate and subject to change or deletion.
Quote
Use at your own risk.
Down 1,900,302 km2 (14.71%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
8,787,047 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
 
Down 115,006 km2 (-1.03%) from previous day.
994,026 km2 below 2000s average for this date.
661,057 km2 below 2010s average for this date.
812,250 km2 below 2015 value for this date.
979,720 km2 below 2012 value for this date.

Part of Jim's data is above.

For those wanting a "visual idea".  That 812,250 km2 is just under TWICE THE SIZE OF TEXAS.  That's....a LOT.
On behalf of New Scientists' Feedback page can I  ask how big is that in Elephant Hides ;D

Using the formula S = -8.245 + 6.807H + 7.073FFC
(Estimation of the total surface area in Indian elephants (Elephas maximus indicus) Sreekumar / Nirmalan et al (http://www.ncbi.nlm.nih.gov/pubmed/2316192)), it's calculated that an average pachyderm has a surface area of about 20 square meters. Thus, (812,250 km2 / 1,000,000) / 20 = 40,612,500,000, or 40.6125 billion elephants.

Oh sure. You use the smaller Indian elephant to exaggerate the problem.  >:(

Hey, don't blame me; 'twas Sreekumar & Nirmalan who wrote the paper.They're obviously part of the dark-money Worldwide Elephant Hide Area Comparsion cabal. Bastards...
Title: Re: 2016 sea ice area and extent data
Post by: Tensor on May 07, 2016, 01:30:35 AM


Hey, don't blame me; 'twas Sreekumar & Nirmalan who wrote the paper.They're obviously part of the dark-money Worldwide Elephant Hide Area Comparsion cabal. Bastards...

Ahhhhhhh, yes, the Elephanati.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 07, 2016, 03:27:51 PM
ADS-NIPR Extent:
11,986,358 km2 (06 May)
NOTE: Earliest sub-12M reading by six days; ahead of ten-year average by > 13 days
Down 1,956,149 km2 (14.03%) from 2016 maximum of 13,942,507 km2 on 29 February.
8,808,903 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 52,727 km2 (-.44%) from previous day.
Down 361,622 km2  (-2.93%) over past seven days (daily average: -51,660 km2).
Down 307,089 km2  (-2.51%) for May (daily average: -51,182 km2).
871,517 km2 below 2000s average for this date.
591,431 km2 below 2010s average for this date.
438,752 km2 below 2015 value for this date.
838,282 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 06 May) average.
Lowest May to-date average.
Lowest value for the date.
72 days this year (57.14% year-to-date) have recorded the lowest daily extent.
27 days (21.43%) have recorded the second lowest.
14 days (11.11%) have recorded the third lowest.
113 days in total (89.68%) have been among the lowest three on record.
Title: Re: 2016 sea ice area and extent data
Post by: Tor Bejnar on May 07, 2016, 04:43:26 PM
Quote
Down 1,956,149 km2 (14.03%) from 2016 maximum of 13,942,507 km2 on 29 February.
(emphases added)

I'm curious how this relates to other years.  2016 started from a lower place than other years, so if decline matched another year (with a similar start date, at least), 2016's extent would stay below it.  But 1980 (as a random selection) started its melt season with a lot more ice, and I don't have much clue as to which year lost more ice between max and today.  I believe someone else was asking about percent decline, perhaps a more meaningful guage.
Title: Re: 2016 sea ice area and extent data
Post by: DavidR on May 07, 2016, 05:11:43 PM
Quote
Down 1,956,149 km2 (14.03%) from 2016 maximum of 13,942,507 km2 on 29 February.
(emphases added)

I'm curious how this relates to other years.  2016 started from a lower place than other years, so if decline matched another year (with a similar start date, at least), 2016's extent would stay below it.  But 1980 (as a random selection) started its melt season with a lot more ice, and I don't have much clue as to which year lost more ice between max and today.  I believe someone else was asking about percent decline, perhaps a more meaningful guage.
Based on the IJIS record since 2003, this is the third biggest decline in the record. The two declines that were bigger, 2003 and 2004 had more than 750,000 km^2 more ice at the maximum.  They declined  300 - 400K km^2 more.

Another way to look at it is that, based on todays figures, extent will need to decline from now, by the smallest amount since 2006  for it not to be the lowest or second lowest minimum on record.
Title: Re: 2016 sea ice area and extent data
Post by: anotheramethyst on May 08, 2016, 07:56:57 AM
We've had a lot of days in a row that were the lowest on record.  What's the most consecutive "lowest IJIS extent on record" days?  How many days with it take to beat that record?
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on May 08, 2016, 08:02:20 AM
We've had a lot of days in a row that were the lowest on record.  What's the most consecutive "lowest IJIS extent on record" days?  How many days with it take to beat that record?
We're looking at it right now.  We beat it every day. 2012 might be an exception, but I don't have the data in front of me.  That would have been on the front end rather than back end - after we'd passed other years heading towards the minimum.  Even then, I doubt it made 90+ days worth.
Title: Re: 2016 sea ice area and extent data
Post by: DavidR on May 08, 2016, 09:12:45 AM
We've had a lot of days in a row that were the lowest on record.  What's the most consecutive "lowest IJIS extent on record" days?  How many days with it take to beat that record?
We're looking at it right now.  We beat it every day. 2012 might be an exception, but I don't have the data in front of me.  That would have been on the front end rather than back end - after we'd passed other years heading towards the minimum.  Even then, I doubt it made 90+ days worth.
In the period leading up to 2007 long record runs were commonplace in IJIS because of the very short record. 2007 had 132 continuous record breaking days from Jul 3rd.

Since 2007 the longest record breaking run was 2012's 83 days from July 25th.  2010 had 40 record breaking days from May 31st.  2015 had 31 days from May 11th and 2011 had 30 days from Dec 18th  2010.

2016 currently has 39 consecutive record days and little prospect of losing the record in the next three weeks. We are currently  255 K km^2 below the previous record and the record declines very slowly over the next week compared to the average decline in that  period until 2015 takes over from 2006 as the record holder on May 11th.

To break the 2012 run, 2016 would have to retain the record until June 21 when the record is held by 2010 with 9,727,850. This would need a loss of 2,184,729 Km^2 between now and then.  Since 2007 only 2013 has lost less than that over that  period and both 2010 and 2012 lost more than 3,000,000 km^2.

Title: Re: 2016 sea ice area and extent data
Post by: anotheramethyst on May 08, 2016, 08:13:02 PM
Thanks!  That's so fascinating.  I never thought about how the early years of the satellite would have a bias.  Haha I guess JAXA's first year, 365 days were lowest (and highest) on JAXA's record. Haha :)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 11, 2016, 02:11:18 PM
ADS-NIPR Extent:
11,633,343 km2 (10 May)
Down 2,309,164 km2 (16.56%) from 2016 maximum of 13,942,507 km2 on 29 February.
8,455,888 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 49,817 km2 (-.43%) from previous day.
Down 511,104 km2  (-4.21%) over past seven days (daily average: -73,015 km2).
Down 660,104 km2  (-5.4%) for May (daily average: -66,010 km2).
1,022,807 km2 below 2000s average for this date.
687,388 km2 below 2010s average for this date.
479,473 km2 below 2015 value for this date.
1,039,956 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 10 May) average.
Lowest May to-date average.
Lowest value for the date.
76 days this year (58.46% year-to-date) have recorded the lowest daily extent.
27 days (20.77%) have recorded the second lowest.
14 days (10.77%) have recorded the third lowest.
117 days in total (90.%) have been among the lowest three on record.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 11, 2016, 06:12:36 PM
Unfortunately neither NSIDC publishes real time  sea ice extent nor does CT appear to have switched to the preliminary F18 sea ice concentration data.

If CT would have, I could have reported a -180k drop is expected for coming Friday.:

day  CT-date       NH               SH                Global
Mon 2016.3479  -75.3 10.917531  +95.8  7.285143   +20.5 18.202674
Tue 2016.3507  -11.6 10.905968  +45.0  7.330120   +33.4 18.236088
Wed 2016.3534  -35.6 10.870406  +79.9  7.410037   +44.4 18.280443
Thu 2016.3562  -39.3 10.831096 +143.9  7.553953  +104.6 18.385049
Fri 2016.3589 -181.9 10.649181  +42.4  7.596343  -139.5 18.245524


The net drop is partly due to widespread sea ice concentration loss in Chukchi (-78k), made visible in the attached delta map. Nothing similar is visible in sea ice concentration maps produced from Uni Hamburg or Jaxa sea ice concentration. Sea ice concentration calculated by NSIDC is sensitive to not just to melt ponds, but to the beginning of melting. So perhaps we see here the beginning of the surface melt, expected by some. It could be a sensor fluke from the F18 as well of course.

For completeness, NSIDC extent dropped -103k. Nothing in Chukchi, but -51k in Baffin and the remainder in Bering and Okhotsk regions.
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on May 11, 2016, 06:39:34 PM
Unfortunately neither NSIDC publishes real time  sea ice extent nor does CT appear to have switched to the preliminary F18 sea ice concentration data.

If CT would have, I could have reported a -180k drop is expected for coming Friday.:


You should be hire by CT, NSIDC or other, Wipneus. You are doing better work than them!
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on May 11, 2016, 06:56:01 PM
Unfortunately neither NSIDC publishes real time  sea ice extent nor does CT appear to have switched to the preliminary F18 sea ice concentration data.

If CT would have, I could have reported a -180k drop is expected for coming Friday.:


You should be hire by CT, NSIDC or other, Wipneus. You are doing better work than them!

Neven´s Forum, the best place to follow the Arctic Sea Ice.
Anyone would like to make a contribution? The link is here (https://www.paypal.com/us/cgi-bin/webscr?cmd=_flow&SESSION=Wx6a4K-RTRud7PfUSBHX4jSVSYOY3DAK34S9SENj8dmXHYs_OK2RMWMoB3C&dispatch=5885d80a13c0db1f8e263663d3faee8dcce3e160f5b9538489e17951d2c62172)  ;).

Edit: If someone is suspiciuos about the link, I took it from Neven's blog (http://neven1.typepad.com/) . Choose "Support & Donate"
Title: Re: 2016 sea ice area and extent data
Post by: Tealight on May 11, 2016, 11:49:29 PM
If CT would have, I could have reported a -180k drop is expected for coming Friday.:

day  CT-date       NH               SH                Global
Mon 2016.3479  -75.3 10.917531  +95.8  7.285143   +20.5 18.202674
Tue 2016.3507  -11.6 10.905968  +45.0  7.330120   +33.4 18.236088
Wed 2016.3534  -35.6 10.870406  +79.9  7.410037   +44.4 18.280443
Thu 2016.3562  -39.3 10.831096 +143.9  7.553953  +104.6 18.385049
Fri 2016.3589 -181.9 10.649181  +42.4  7.596343  -139.5 18.245524


Do you have calculated CT area values for all of April until today available for download? I'm working on some Albedo calculations which are based on CT data and the sensor error screws the current year over. I would really appricate it if you could provide the daily area values. Then I can post the results here on the forum before CT switches to F18 in a few weeks or months.

I can't switch to AMSR2 because they don't have any data before 2012.
Title: Re: 2016 sea ice area and extent data
Post by: seaicesailor on May 12, 2016, 12:10:37 AM
Powerful!! Not a fluke...
http://forum.arctic-sea-ice.net/index.php/topic,1493.msg76353.html#msg76353 (http://forum.arctic-sea-ice.net/index.php/topic,1493.msg76353.html#msg76353)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 12, 2016, 08:05:45 AM
Yes. ADS-Jaxa melt map also indicates the first signs of melt here. Even the Uni Hamburg shows a drop in  sea ice concentration where Jaxa shows melt.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 12, 2016, 09:16:31 AM
If CT would have, I could have reported a -180k drop is expected for coming Friday.:

day  CT-date       NH               SH                Global
Mon 2016.3479  -75.3 10.917531  +95.8  7.285143   +20.5 18.202674
Tue 2016.3507  -11.6 10.905968  +45.0  7.330120   +33.4 18.236088
Wed 2016.3534  -35.6 10.870406  +79.9  7.410037   +44.4 18.280443
Thu 2016.3562  -39.3 10.831096 +143.9  7.553953  +104.6 18.385049
Fri 2016.3589 -181.9 10.649181  +42.4  7.596343  -139.5 18.245524


Do you have calculated CT area values for all of April until today available for download? I'm working on some Albedo calculations which are based on CT data and the sensor error screws the current year over. I would really appricate it if you could provide the daily area values. Then I can post the results here on the forum before CT switches to F18 in a few weeks or months.

I can't switch to AMSR2 because they don't have any data before 2012.

I put something together here. Will that do for you?

https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/AreaCalculatedLikeCryosphereToday.txt
Title: Re: 2016 sea ice area and extent data
Post by: Tealight on May 12, 2016, 10:18:54 AM
Thats perfect, thanks.  :)

The F18 values almost perfectly match the official data for the first days of April and give a smooth transitioning.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 12, 2016, 04:24:37 PM
The Chukchi apparent drop in concentration travels forward into the interior (recovery in the wake).

Virtual CT area report:

day  CT-date       NH               SH                Global
Tue 2016.3507  -11.6 10.905968  +45.0  7.330120   +33.4 18.236088
Wed 2016.3534  -35.6 10.870406  +79.9  7.410037   +44.4 18.280443
Thu 2016.3562  -39.3 10.831096 +143.9  7.553953  +104.6 18.385049
Fri 2016.3589 -182.2 10.648849  +42.4  7.596343  -139.9 18.245192
Sat 2016.3616 -162.6 10.486256  +52.7  7.649043  -109.9 18.135299


Extent (virtual NSIDC extent) dropped about -130k. Okhotsk and Bering -40k, remainder in Hudson, Baffin, StLawrence and Greenlands Sea.

Title: Re: 2016 sea ice area and extent data
Post by: crandles on May 12, 2016, 04:48:55 PM
The Chukchi apparent drop in concentration travels forward into the interior (recovery in the wake).

Virtual CT area report:

day  CT-date       NH               SH                Global
Tue 2016.3507  -11.6 10.905968  +45.0  7.330120   +33.4 18.236088
Wed 2016.3534  -35.6 10.870406  +79.9  7.410037   +44.4 18.280443
Thu 2016.3562  -39.3 10.831096 +143.9  7.553953  +104.6 18.385049
Fri 2016.3589 -182.2 10.648849  +42.4  7.596343  -139.9 18.245192
Sat 2016.3616 -162.6 10.486256  +52.7  7.649043  -109.9 18.135299



Lowest .3616 day is 2006 11.091
So if no major adjustments needed, 2016 is currently looking to be around 605k below lowest year on record  :o :o :o
Title: Re: 2016 sea ice area and extent data
Post by: DoomInTheUK on May 12, 2016, 05:59:11 PM
Come September Wipneus will be struggling to find any ice to count at this rate, but we can be pretty sure he'll count what little is left properly.

No end in sight.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 13, 2016, 04:27:16 PM
Sea ice concentration drop progresses further into Beaufort and the CAB (-25k and -49k SIA), while behind the front the concentration is Chukchi recovers (+50k).

The shadow CT-area report:

day  CT-date       NH               SH                Global
Wed 2016.3534  -35.6 10.870406  +79.9  7.410037   +44.4 18.280443
Thu 2016.3562  -39.3 10.831096 +143.9  7.553953  +104.6 18.385049
Fri 2016.3589 -182.2 10.648849  +42.4  7.596343  -139.9 18.245192
Sat 2016.3616 -162.7 10.486125  +52.7  7.649055  -110.0 18.135180
Sun 2016.3644  -68.3 10.417814  +47.1  7.696178   -21.2 18.113992

Shadow NSIDC extent dropped another century (-101k5). No surprises: Okhotsk, Bering, Barents, Greenland Sea and Hudson took their share.
Title: Re: 2016 sea ice area and extent data
Post by: Alphabet Hotel on May 14, 2016, 05:09:39 AM
AMSR2 images from uni-bremen.de are missing for May 12 and May 13. Anyone know what happened?
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on May 14, 2016, 07:22:53 AM
Someone knows what is happening with AMSR2 Arctic maps of Bremen's University? I haven't been able to see them for a couple of days...
I miss them!  ;)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 14, 2016, 04:39:17 PM
Time for an uptick in my shadow CT-area calculation:

day  CT-date       NH               SH                Global
Thu 2016.3562  -39.3 10.831096 +143.9  7.553953  +104.6 18.385049
Fri 2016.3589 -182.2 10.648849  +42.4  7.596343  -139.9 18.245192
Sat 2016.3616 -162.7 10.486125  +52.7  7.649055  -110.0 18.135180
Sun 2016.3644  -67.5 10.418575  +47.2  7.696227   -20.4 18.114802
Mon 2016.3671  +29.2 10.447775 +152.6  7.848805  +181.8 18.296580


The attached delta map shows that yesterday's concentration drop is today's recovery.

Shadow NSIDC extent dropped -28k. Mostly Barents with increases in Baffin and Sea of Okhotsk.
Title: Re: 2016 sea ice area and extent data
Post by: crandles on May 14, 2016, 05:23:38 PM
Wonderful work you do.


The attached delta map shows that yesterday's concentration drop is today's recovery.

Does this seem odd? I don't remember seeing such pronounced behaviour but maybe I wasn't paying appropriate attention to notice and it is normal? Could there be some calibration adjustments required with new sensor to reduce such overshoot behaviour? Or is what is happening just unusual for this early in season and this somehow causes such swings? or some other explanation?

Probably rather difficult to answer without a lot of time and data which we don't yet have with new sensor, so sorry for asking so soon. Asking for any gut feelings might also be too early a question to ask so I hope you don't mind me canvassing any views there might be.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 14, 2016, 05:54:47 PM
Wonderful work you do.


The attached delta map shows that yesterday's concentration drop is today's recovery.

Does this seem odd? I don't remember seeing such pronounced behaviour but maybe I wasn't paying appropriate attention to notice and it is normal? Could there be some calibration adjustments required with new sensor to reduce such overshoot behaviour?

I do not recall seeing this before. I see the same in UH AMSR2 sea ice concentration, and Jaxa's surface melt map. So it is not likely a sensor calibration issue.

Quote
Or is what is happening just unusual for this early in season and this somehow causes such swings? or some other explanation?

Probably rather difficult to answer without a lot of time and data which we don't yet have with new sensor, so sorry for asking so soon. Asking for any gut feelings might also be too early a question to ask so I hope you don't mind me canvassing any views there might be.

I can speculate. Look at the attached UH AMSR2 animation, not as pretty but you can clearly see the blotch of darkening moving from the Bering Strait into Chukchi, turning into and crossing the Beaufort and now going into the CAA. That is so fast and unlike other torching phenomena that I have been observing. Those movement where going with the ice, much much slower.
So I come to weather, could it be a rain front, wetting the surface temporary, and since the conditions are not ready for melt yet the surface quickly dries after the rain stops?
Title: Re: 2016 sea ice area and extent data
Post by: ktonine on May 14, 2016, 06:20:17 PM
Wonderful work you do.


The attached delta map shows that yesterday's concentration drop is today's recovery.

Does this seem odd? I don't remember seeing such pronounced behaviour but maybe I wasn't paying appropriate attention to notice and it is normal? Could there be some calibration adjustments required with new sensor to reduce such overshoot behaviour? Or is what is happening just unusual for this early in season and this somehow causes such swings? or some other explanation?

Probably rather difficult to answer without a lot of time and data which we don't yet have with new sensor, so sorry for asking so soon. Asking for any gut feelings might also be too early a question to ask so I hope you don't mind me canvassing any views there might be.

It might be interesting to check a buoy - if there's one in the path - or a land station to see if the concurrent weather (temp., rain, fog, snow ?) can tell us what the sensors are seeing (and confused by).  Of course it could be something at a higher atmospheric altitude that is confounding the sensors and this wouldn't necessarily be apparent at the surface.
Title: Re: 2016 sea ice area and extent data
Post by: plinius on May 14, 2016, 08:05:22 PM
isn't that quite exactly what obuoy 14 has seen?
http://obuoy.datatransport.org/monitor#buoy14/weather (http://obuoy.datatransport.org/monitor#buoy14/weather)

About 1 day above freezing temperature, and then a very sudden drop to temperatures ensuring that the surface freezes up again. Given that there is porous snow and no melt ponds, the surface layer/thin film of water would have disappeared almost instantly.


Title: Re: 2016 sea ice area and extent data
Post by: oren on May 14, 2016, 08:58:48 PM
Yeah my thinking too, something (probably the high temps that were forecast) made the snow wet and the sensor thought it was water, then everything froze up again. With lower albedo though.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on May 15, 2016, 11:49:03 AM
I'm gonna update the missing weekly NSIDC extent reports from April 9th, so sorry for the spamming to follow!

Update for the week to April 9th

The current 5 day mean is on 13,969,500km2 while the 1 day extent is at 13,870,000km2.

The daily anomaly (compared to 81-10) is at -1,057,960km2, a decrease from -1,063,590km2 last week. The anomaly compared to the 07, 11 and 12 average is at -477,130km2, an increase from -453,470km2 last week. We're currently lowest on record, the same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FtkHZQB3.png&hash=8aef164a76ed8213ef70cf9d84d1d77e)

The average daily change over the last 7 days was -32.3k/day, compared to the long term average of -32.7k/day, and the 07, 11 and 12 average of -28.5k/day.
The average long term change over the next week is -40.4k/day, with the 07, 11, and 12 average being -29.1k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FYPQMtkY.png&hash=412c582e080bef7d73eb2e8a01ef6bd1)

The extent drop so far this April is the 12th largest record. To achieve the largest monthly loss, a drop of at least 60.6k/day is required, while the smallest loss requires a drop of less than 16.7k/day and an average loss requires a drop of 35.8k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FBd5ry5B.png&hash=e659f550a765d685c9c73902a01b3265)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on May 15, 2016, 12:03:55 PM
Update for the week to April 16th

The current 5 day mean is on 13,859,600km2 while the 1 day extent is at 13,822,000km2.

The daily anomaly (compared to 81-10) is at -885,320km2, a decrease from -1,063,590km2 last week. The anomaly compared to the 07, 11 and 12 average is at -383,550km2, a decrease from -453,470km2 last week. We're currently second lowest on record, down from lowest last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FBeigjcE.png&hash=68c17c02c6db3558272bef714c5e5303)

The average daily change over the last 7 days was -15.7k/day, compared to the long term average of -32.7k/day, and the 07, 11 and 12 average of -28.5k/day.
The average long term change over the next week is -36.6k/day, with the 07, 11, and 12 average being -23.2k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FV9YOI9M.png&hash=dd1c021ade7f73dedcda61d1bc7b4223)

The extent drop so far this April is the 13th smallest on record. To achieve the largest monthly loss, a drop of at least 83.1k/day is required, while the smallest loss requires a drop of less than 17.2k/day and an average loss requires a drop of 45.9k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F91NJh9n.png&hash=851b42d23f4401d6a4856bc553034ccc)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on May 15, 2016, 12:23:03 PM
Update for the week to April 23rd

The current 5 day mean is on 13,549,700km2 while the 1 day extent is at 13,492,000km2.

The daily anomaly (compared to 81-10) is at -939,230km2, an increase from -885,320km2 last week. The anomaly compared to the 07, 11 and 12 average is at -530,830km2, an increase from -383,550km2 last week. We're currently the lowest on record, up from second lowest last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FlnTWeCd.png&hash=79af51de36b41e6fc666d5efd4fe7f2a)

The average daily change over the last 7 days was -44.3k/day, compared to the long term average of -36.6k/day, and the 07, 11 and 12 average of -23.2k/day.
The average long term change over the next week is -43.2k/day, with the 07, 11, and 12 average being -49.4k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FrQrTk5z.png&hash=a8f144f59d0b7ff0a1777e8842ed5167)

The extent drop so far this April is the 17th smallest on record. To achieve the largest monthly loss, a drop of at least 121.8k/day is required, while the smallest loss requires an increase of at least than 9.9k/day and an average loss requires a drop of 47.5k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FdQL9A3C.png&hash=709c5ed69cc32dfe3cafc4964f3abb4e)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on May 15, 2016, 12:38:24 PM
Update for the week to April 30th

The current 5 day mean is on 13,142,400km2 while the 1 day extent is at 12,990,000km2.

The daily anomaly (compared to 81-10) is at -1,044,140km2, an increase from -939,230km2 last week. The anomaly compared to the 07, 11 and 12 average is at -592,380km2, an increase from -530,830km2 last week. We're currently the lowest on record, the same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F5JAXhpl.png&hash=d12faa2cd1716f84c2c879755c931c44)

The average daily change over the last 7 days was -58.2k/day, compared to the long term average of -43.2k/day, and the 07, 11 and 12 average of -49.4k/day.
The average long term change over the next week is -60.6k/day, with the 07, 11, and 12 average being -61.1k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F6AJHWdJ.png&hash=b02f1bca6caea3bb0b6be2ef8d90a138)

The extent loss in April was the 15th largest on record, while the average extent was the lowest on record.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FzjDadA2.png&hash=4751a6d6392e2a4f30232760b68dd583)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FS7vPYOf.png&hash=c656483a63e5554ba29c90e87f473dda)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on May 15, 2016, 12:56:07 PM
Update for the week to May 7th

The current 5 day mean is on 12,580,300km2 while the 1 day extent is at 12,455,000km2.

The daily anomaly (compared to 81-10) is at -1,182,030km2, an increase from -1,044,140km2 last week. The anomaly compared to the 07, 11 and 12 average is at -726,560km2, an increase from -592,380km2 last week. We're currently the lowest on record, the same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FediuJLk.png&hash=b2709f4537c715655aa843ac00162e0b)

The average daily change over the last 7 days was -80.3k/day, compared to the long term average of -60.6k/day, and the 07, 11 and 12 average of -61.1k/day.
The average long term change over the next week is -42.6k/day, with the 07, 11, and 12 average being -41.1k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FhLe2erm.png&hash=477b6ca47a69ae238f3767cecade4f20)

The extent drop so far this May is the 7th largest on record. To achieve the largest monthly loss, a drop of at least 65.6k/day is required, while the smallest loss requires a drop of less than 11.3k/day and an average loss requires a drop of 37.3k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F93EG20C.png&hash=b86c28c13264f08fcf9ee826135ad2cb)
Title: Re: 2016 sea ice area and extent data
Post by: Tor Bejnar on May 15, 2016, 02:29:22 PM
Thanks, BFTV.  I've sure missed these postings - glad they are back from the void!  ;)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 15, 2016, 05:45:42 PM
The shadow CT-area calculations:

day  CT-date       NH               SH                Global
Fri 2016.3589 -182.2 10.648849  +42.4  7.596343  -139.9 18.245192
Sat 2016.3616 -162.7 10.486125  +52.7  7.649055  -110.0 18.135180
Sun 2016.3644  -67.5 10.418575  +47.2  7.696227   -20.4 18.114802
Mon 2016.3671  +29.9 10.448430 +152.7  7.848879  +182.5 18.297309
Tue 2016.3699  -62.7 10.385694 +120.6  7.969448   +57.8 18.355142


Biggest decliners where ESS and Hudson (both about -20k).

Shadow NSIDC extent dropped -68k9. Sea of Okhotsk (-37k) and Barents (-26k) dropped most.

The usual delta map is attached.
In the Chukchi and Beaufort region the situation seems to stabilise. The remaining darker patches may indicate where the surface is most wet from rain/melting/sea water or where perhaps it is due to open water in unresolved leads.
Title: Re: 2016 sea ice area and extent data
Post by: Sourabh on May 15, 2016, 05:55:39 PM
BFV,

I also missed your updates. Given the recent IJIS drops, your next update would be more interesting.
Title: Re: 2016 sea ice area and extent data
Post by: Sourabh on May 15, 2016, 06:36:56 PM
Wipneus,

I should have asked this here, and not in the melting season thread.

If possible and if it is not too much to ask, could you also make an updated CAPIE chart to show how this year is doing as compared to previous years? Generally, Neven does that, but just like arctic ice, he has disappeared from this forum lately ( ;D).
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 15, 2016, 07:05:43 PM
Wipneus,

I should have asked this here, and not in the melting season thread.

If possible and if it is not too much to ask, could you also make an updated CAPIE chart to show how this year is doing as compared to previous years? Generally, Neven does that, but just like arctic ice, he has disappeared from this forum lately ( ;D).

Sourabh, I really think CAPIE is Neven's thing. If I remember correctly he announced to be away for one or two weeks, so he should be back soon enough.

If you are interested in area by extent ratio I can recommend my graph from the "home brew" thread because this is called by (some) scientists "compactness". Area and extent are of course from the same source, CAPIE uses different sources.

https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-compact-compare.png

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-compact-compare.png)

There is a regional version as well:

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

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-compact-regional.png)
Title: Re: 2016 sea ice area and extent data
Post by: Sourabh on May 15, 2016, 07:19:23 PM
Thanks Wipneus,

Neven generally divides CT area with IJIS extent to get CAPIE.

In your graph, three different sources of compactness are telling different stories. In NSIDC compactness, 2016 is lower range as compared to other years. But, in Uni Hamburg, it is in upper range.

I was thinking if compactness is also low during May with already lower extent, then this year is likely to be extraordinary. With open skies and lots of melt ponds, there could be possibility of a significant melting momentum. But, I leave the intellectual interpretation of the data to you, Chris, and Neven.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on May 15, 2016, 08:51:33 PM
Update for the week to May 14th

The current 5 day mean is on 12,083,300km2 while the 1 day extent is at 11,945,000km2.

The daily anomaly (compared to 81-10) is at -1,380,810km2, an increase from -1,182,030km2 last week. The anomaly compared to the 07, 11 and 12 average is at -935,880km2, an increase from -726,560km2 last week. We're currently the lowest on record, the same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FppN4Rg7.png&hash=c6c66ffc0d1cd42e8d28c21a80f6ed25)

The average daily change over the last 7 days was -71.0k/day, compared to the long term average of -42.6k/day, and the 07, 11 and 12 average of -41.1k/day.
The average long term change over the next week is -45.4k/day, with the 07, 11, and 12 average being -45.5k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FMfWTxqK.png&hash=ef7ccda82d5754e6bdb104287a18019e)

The extent drop so far this May is the 3rd largest on record. To achieve the largest monthly loss, a drop of at least 63.3k/day is required, while the smallest loss requires an increase of at least 13.4k/day and an average loss requires a drop of 23.5k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fe6ON4xO.png&hash=ee35df695880fc3e6371d4a9f7173fc8)
Title: Re: 2016 sea ice area and extent data
Post by: Tealight on May 15, 2016, 11:10:22 PM
As it seems today is offical graph posting day. So I contribute a Cryosphere Today area graph based on Wipneus calculations.

Currently 2016 is exactly 500,000 km2 below the previous record low from 2011.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 16, 2016, 02:39:19 PM
ADS-NIPR Extent:
11,262,361 km2 (15 May)
Down 2,680,146 km2 (19.22%) from 2016 maximum of 13,942,507 km2 on 29 February.
8,084,906 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 31,365 km2 (-.28%) from previous day.
Down 519,805 km2  (-4.41%) over past seven days (daily average: -74,258 km2).
Down 1,031,086 km2  (-8.43%) for May (daily average: -68,739 km2).
1,166,219 km2 below 2000s average for this date.
773,876 km2 below 2010s average for this date.
604,920 km2 below 2015 value for this date.
1,107,042 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 15 May) average.
Lowest May to-date average.
Lowest value for the date.
81 days this year (60% year-to-date) have recorded the lowest daily extent.
27 days (20%) have recorded the second lowest.
14 days (10.37%) have recorded the third lowest.
122 days in total (90.37%) have been among the lowest three on record.


CT Area*:
10,448,430 km2 (15 May [Day 0.3671])
Down 2,472,928 km2 (19.14%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
8,214,421 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Up 29,855 km2 (.29%) from previous day.
Down 469,101 km2 (-4.3%) over past seven days (daily average: -67,014 km2).
Down 768,902 km2 (-6.9%) for May (daily average: -51,260 km2).
1,047,044 km2 below 2000s average for this date.
628,854 km2 below 2010s average for this date.
665,033 km2 below 2015 value for this date.
906,254 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.3671) average.
Lowest May to-date average.
Lowest value for the date.
* -Due to ongoing satellite issues, multiple days in the Cryosphere Today 2016 dataset are missing and/or invalid; for that reason, these numbers include Wipneus's calculated area numbers instead of the actual published numbers
   
Title: Re: 2016 sea ice area and extent data
Post by: mmghosh on May 16, 2016, 03:43:31 PM
More graphs from tamino

https://tamino.wordpress.com/2016/05/16/arctic-dive/
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 16, 2016, 04:35:35 PM
The shadow CT-area report:

day  CT-date       NH               SH                Global
Sun 2016.3644  -67.5 10.418575  +47.2  7.696227   -20.4 18.114802
Mon 2016.3671  +29.9 10.448430 +152.7  7.848879  +182.5 18.297309
Tue 2016.3699  -62.6 10.385816 +120.6  7.969487   +58.0 18.355303
Wed 2016.3726  -64.4 10.321439  +68.4  8.037935    +4.1 18.359374

Hudson Bay contributed most (-31k), followed by the CAB (-19k).

Shadow NSIDC extent declined only -25k, Baffin and Barents doing the job.

In the delta map from the NSIDC sea ice concentration, the drop in Hudson is clear. Except for the East Siberian Sea,  most of the Arctic Basin saw small changes.
Title: Re: 2016 sea ice area and extent data
Post by: LRC1962 on May 16, 2016, 09:40:07 PM

The extent drop so far this May is the 3rd largest on record. To achieve the largest monthly loss, a drop of at least 63.3k/day is required, while the smallest loss requires an increase of at least 13.4k/day and an average loss requires a drop of 23.5k/day.
The scary part is that it is the 3rd largest drop and at the same time the lowest extent we have ever had. Put the 2 together and by percentages the Arctic is dropping very fast.
Title: Re: 2016 sea ice area and extent data
Post by: abbottisgone on May 17, 2016, 11:10:18 AM

The extent drop so far this May is the 3rd largest on record. To achieve the largest monthly loss, a drop of at least 63.3k/day is required, while the smallest loss requires an increase of at least 13.4k/day and an average loss requires a drop of 23.5k/day.
The scary part is that it is the 3rd largest drop and at the same time the lowest extent we have ever had. Put the 2 together and by percentages the Arctic is dropping very fast.
I don't know anything about the concept of hysteresis so tried to use it over at skeptical science and quickly got told there is, as yet, no hysteresis as regards the discussion of the worlds sea ice at the moment but the concept does have a valid place when discussing land ice.

I remain willing to accept the word of others with better knowledge but feel the idea should probably get a guernsey somewhere along the line as we are talking about a potentially very serious point in time about now.

Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 17, 2016, 04:16:49 PM
The shadow CT area report:

day  CT-date       NH               SH                Global
Mon 2016.3671  +29.9 10.448430 +152.7  7.848879  +182.5 18.297309
Tue 2016.3699  -62.6 10.385816 +120.6  7.969487   +58.0 18.355303
Wed 2016.3726  -64.6 10.321244  +68.4  8.037935    +3.9 18.359179
Thu 2016.3753  -33.3 10.287978 +129.6  8.167545   +96.3 18.455523


CAB dropped -20k, Laptev -14k.

Shadow NSIDC extent went down just -8k8, CAB -16k, StLawrence +18k changed most.

The little change can be seen in the attached delta map. Hudson sees some drops in concentration and increases elsewhere.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 18, 2016, 01:19:22 PM
ADS-NIPR Extent:
11,144,719 km2 (17 May)
Down 2,797,788 km2 (20.07%) from 2016 maximum of 13,942,507 km2 on 29 February.
7,967,264 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 53,190 km2 (-.47%) from previous day.
Down 488,624 km2  (-4.2%) over past seven days (daily average: -69,803 km2).
Down 1,148,728 km2  (-9.39%) for May (daily average: -67,572 km2).
1,188,821 km2 below 2000s average for this date.
777,532 km2 below 2010s average for this date.
606,845 km2 below 2015 value for this date.
1,033,524 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 17 May) average.
Lowest May to-date average.
Lowest value for the date.
83 days this year (60.58% year-to-date) have recorded the lowest daily extent.
27 days (19.71%) have recorded the second lowest.
14 days (10.22%) have recorded the third lowest.
124 days in total (90.51%) have been among the lowest three on record.


CT Area*:
10,287,978 km2 (18 May [Day 0.3754])
Down 2,633,380 km2 (20.38%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
8,053,969 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 33,266 km2 (-.32%) from previous day.
Down 543,118 km2 (-5.1%) over past seven days (daily average: -77,588 km2).
Down 929,354 km2 (-8.34%) for May (daily average: -51,631 km2).
1,029,512 km2 below 2000s average for this date.
599,767 km2 below 2010s average for this date.
568,373 km2 below 2015 value for this date.
782,051 km2 below 2012 value for this date.
Lowest value for the date.
* - Due to ongoing satellite issues, multiple days in the Cryosphere Today 2016 data are missing and/or invalid; for that reason, this table incorporates sea ice area figures as calculated by Wipneus using NSIDC's numbers.



Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 18, 2016, 05:20:01 PM
The shadow CT-area report:


day  CT-date       NH               SH                Global
Tue 2016.3699  -62.6 10.385816 +120.6  7.969487   +58.0 18.355303
Wed 2016.3726  -64.6 10.321244  +68.4  8.037935    +3.9 18.359179
Thu 2016.3753  -33.3 10.287944 +129.6  8.167545   +96.3 18.455489
Fri 2016.3781  -72.1 10.215845 +144.5  8.312020   +72.4 18.527865


The Kara (-24k) and ESS (-21k) and Beaufort (-11k) were contributors. Hudson increased by (+18k).

Shadow NSIDC dropped over a century (-130k). Here Baffin (-33k), Greenland Sea (-23k) and StLawrence (-16k) were contributors. There is also a large drop (-29k) outside the well known regions, from the delta map I guess that is mostly the Baltic.

In that delta map we can see a drop along the cracked zone in the East Siberian Sea.
Title: Re: 2016 sea ice area and extent data
Post by: Sebastian on May 18, 2016, 10:17:17 PM
The drop in the baltic was false ice going away again as the sea is about 10 degrees warm in the gulf of finland http://en.ilmatieteenlaitos.fi/ice-conditions (http://en.ilmatieteenlaitos.fi/ice-conditions)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 19, 2016, 04:34:49 PM
Shadow CT-area report:


day  CT-date       NH               SH                Global
Wed 2016.3726  -64.6 10.321244  +68.4  8.037935    +3.9 18.359179
Thu 2016.3753  -33.3 10.287944 +129.6  8.167545   +96.3 18.455489
Fri 2016.3781  -72.1 10.215796 +144.5  8.312095   +72.4 18.527891
Sat 2016.3808  -73.3 10.142537  +29.9  8.341968   -43.4 18.484505


The drop is shared over many regions, none stand out, but see attached delta map for  some activity in Hudson and Kara.

Shadow NSIDC extent dropped -61.8. The Sea of Okhotsk managed to squeeze another -37k, Chukchi did -12k.


Title: Re: 2016 sea ice area and extent data
Post by: jdallen on May 19, 2016, 07:36:00 PM
With the heat coming in (looking at Climate Reanalyzer), I'm expecting both the Bering and Okhostsk to get finished off this week, and major inroads made into the Chukchi, Kara and Barents.

There will be heat along the Beaufort as well, but I'm not sure that will have as much of an impact on numbers.  It's quite possible we'll see a slackening of pace similar to that pointed out by OldLeatherneck on a different thread.
Title: Re: 2016 sea ice area and extent data
Post by: sedziobs on May 19, 2016, 07:49:39 PM
The bigger impact on Beaufort may be the return of high pressure in the central Arctic, which gradually builds through the forecast.  That should result in winds further expanding the open water area.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 20, 2016, 04:48:19 PM
The shadow CT-area report:
> source("xctarea.R")

day  CT-date       NH               SH                Global
Thu 2016.3753  -33.3 10.287944 +129.6  8.167545   +96.3 18.455489
Fri 2016.3781  -72.1 10.215796 +144.5  8.312095   +72.4 18.527891
Sat 2016.3808  -73.6 10.142238  +29.9  8.342009   -43.6 18.484247
Sun 2016.3836  -56.5 10.085746  +82.1  8.424107   +25.6 18.509853

Baffin, Chukchi and OKhotsk dropped each about -12k. ESS went up +11k.

Shadow NSIDC is 11.6092 (-108k4). Okhotsk dropped -31k (129k remaining) , Bering -16k (100k remains) StLawrence -13k (30k remains). Greenland Sea dropped -17k (plenty left).

An overview of the changes can be seen in the attached delta map.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 21, 2016, 04:35:58 PM
Shadow CT-area report:

day  CT-date       NH               SH                Global
Fri 2016.3781  -72.1 10.215796 +144.5  8.312095   +72.4 18.527891
Sat 2016.3808  -73.6 10.142238  +29.9  8.342009   -43.6 18.484247
Sun 2016.3836  -56.5 10.085765  +82.4  8.424402   +25.9 18.510167
Mon 2016.3863  -26.0 10.059755   -0.2  8.424190   -26.2 18.483945

Baffin decreased by -25k, the CAB rebounded +13k.

Shadow NSIDC is 11.5957, down -13k. Hudson took care of that: -15k.
 
An overview of the changes can be seen in the attached delta map.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 22, 2016, 04:28:54 PM
Shadow CT-area report:

day  CT-date       NH               SH                Global
Sat 2016.3808  -73.6 10.142238  +29.9  8.342009   -43.6 18.484247
Sun 2016.3836  -56.5 10.085765  +82.4  8.424402   +25.9 18.510167
Mon 2016.3863  -25.9 10.059819   -0.4  8.423993   -26.4 18.483812
Tue 2016.3890  -68.6  9.991219  +66.9  8.490880    -1.7 18.482099


That is due to the big drop in Kara (-43k) and a much lesser one in Hudson region (-22k).

The shadow NSIDC extent is 11.6247  (+29k). The uptick comes from Okhotsk (+20k) and Greenland Sea (+13k). Hudson dropped -15k.

In the attached delta map, the concentration drop in Kara is clearly visible.


Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on May 22, 2016, 04:46:07 PM
Update for the week to May 21st

The current 5 day mean is on 11,665,400km2 while the 1 day extent is at 11,625,000km2.

The daily anomaly (compared to 81-10) is at -1,481,130km2, an increase from -1,380,810km2 last week. The anomaly compared to the 07, 11 and 12 average is at -1,035,250km2, an increase from -935,880km2 last week. We're currently the lowest on record, the same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fk7mgx8k.png&hash=5cf36c32cab816a20a5c6efff07f7c0f)

The average daily change over the last 7 days was -59.7k/day, compared to the long term average of -45.4k/day, and the 07, 11 and 12 average of -45.5k/day.
The average long term change over the next week is -48.8k/day, with the 07, 11, and 12 average being -54.7k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fp7rEj2e.png&hash=253bca2ac9cb8001eb0965f2abed3b18)

The extent drop so far this May is the 2nd largest on record. To achieve the largest monthly loss, a drop of at least 65.8k/day is required, while the smallest loss requires an increase of at least 66.5k/day and an average loss requires a increase of 1.9k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FJIkUUcw.png&hash=600c388c1588e02f5ed900e30f3098a5)
Title: Re: 2016 sea ice area and extent data
Post by: abbottisgone on May 22, 2016, 06:10:54 PM
..typos?
Title: Re: 2016 sea ice area and extent data
Post by: Nick_Naylor on May 22, 2016, 08:33:52 PM
The 5-day mean looks understated. Are you seeing something else?
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on May 22, 2016, 09:19:06 PM
..typos?

Where?
Title: Re: 2016 sea ice area and extent data
Post by: Nick_Naylor on May 22, 2016, 09:23:33 PM
..typos?

Where?

Shouldn't the 5 day mean be at least 100k higher than the most recent extent?
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on May 22, 2016, 09:28:31 PM
..typos?

Where?

Shouldn't the 5 day mean be at least 100k higher than the most recent extent?

The daily extent values have actually risen slightly in the last 3 days (19th: 11.609, 20th: 11.596, 21st: 11.625), hence the small gap now between the single day and 5 day average.

If there isn't a big drop in the daily value tomorrow, the 5 day average will see a big slow down too.
Title: Re: 2016 sea ice area and extent data
Post by: Nick_Naylor on May 22, 2016, 10:04:36 PM
Thanks. I sure didn't see that in the curve  :o
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on May 23, 2016, 10:26:43 AM
Thanks. I sure didn't see that in the curve  :o

My own graphs use the 5 day average, as do the NSIDC. I can try to make that more clear in future posts.
Title: Re: 2016 sea ice area and extent data
Post by: Nick_Naylor on May 23, 2016, 01:01:17 PM
That might be helpful, although in retrospect the charts are obviously too smooth to be anything else.
What I meant to say is that - even knowing it's a 5 day average - it's hard to see what daily values would have to be in order to give the chart and the stats at the same time.
I'm still not understanding what prompted the original "typos?" posting though.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 23, 2016, 04:20:20 PM
The shadow CT-area report:

day  CT-date       NH               SH                Global
Sun 2016.3836  -56.5 10.085765  +82.4  8.424402   +25.9 18.510167
Mon 2016.3863  -25.9 10.059819   -0.4  8.423993   -26.4 18.483812
Tue 2016.3890  -68.5  9.991272  +66.9  8.490915    -1.6 18.482187
Wed 2016.3918  -94.4  9.896835  +69.8  8.560710   -24.6 18.457545

Hudson (-36k), Chukchi (-25k) and Beaufort (-18k) are main contributors.

Shadow NSIDC for 2016/5/22 was 11.5913  (-33.3k). No particular region stands out.

The changes can be seen in attached delta map.
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on May 24, 2016, 06:59:33 AM
Wipneus,
I'm sure that I speak on behalf of the ASIB/ASIF community if I want to THANK YOU for the marvelous work you are doing.
Due to the F-17 issues, many of the regular sea ice information sources are disfunctional, which leaves your data as a crucial source of information of what is going on during this epic melting season.

Especially the AMSR2 regional graphs that you produce on the arctischepinguin site are essential, as and the 'shadow' CT area and 'shadow' NSIDC area and extent info are just phenomenal.

Just one question : Do you have a graph (or a data file) for the 'shadow' CT area and 'shadow' NSIDC area and extent ?
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 24, 2016, 09:27:42 AM
Wipneus,
I'm sure that I speak on behalf of the ASIB/ASIF community if I want to THANK YOU for the marvelous work you are doing.
Due to the F-17 issues, many of the regular sea ice information sources are disfunctional, which leaves your data as a crucial source of information of what is going on during this epic melting season.

Especially the AMSR2 regional graphs that you produce on the arctischepinguin site are essential, as and the 'shadow' CT area and 'shadow' NSIDC area and extent info are just phenomenal.

Just one question : Do you have a graph (or a data file) for the 'shadow' CT area and 'shadow' NSIDC area and extent ?

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

Browse in the folder for antarctic and regional data files.

I do not graph CT-area at all, it is not a very good indication of area IMHO. Area in the NSIDC files/graphs (sometimes referred to as NSIDC-area) is calculated from the same SIC data in the way as you would have expected it.

NSIDC extent (and area) appear in many of graphs. Some samples:
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc-nt-regional-area-overview.png
https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/grf/nsidc-nt-regional-extent-overview.png
https://sites.google.com/site/arctischepinguin/home/amsr2/grf/basin-area-multiprod.png
https://sites.google.com/site/arctischepinguin/home/amsr2/grf/basin-extent-multiprod.png

Browsing in the folders is allowed.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on May 24, 2016, 09:56:06 AM
That might be helpful, although in retrospect the charts are obviously too smooth to be anything else.
What I meant to say is that - even knowing it's a 5 day average - it's hard to see what daily values would have to be in order to give the chart and the stats at the same time.
I'm still not understanding what prompted the original "typos?" posting though.

I'm always open to suggestions, whether it be for new graphs or different ways to explain what they're showing. I'll see if I can change the wording to make the post more clear next time, maybe some extra stats to clarify things too.
Title: Re: 2016 sea ice area and extent data
Post by: oren on May 24, 2016, 10:41:36 AM
Wipneus,
I'm sure that I speak on behalf of the ASIB/ASIF community if I want to THANK YOU for the marvelous work you are doing.
+1
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 24, 2016, 02:03:53 PM
ADS-NIPR Extent:
10,880,319 km2 (23 May)
Down 3,062,188 km2 (21.96%) from 2016 maximum of 13,942,507 km2 on 29 February.
7,702,864 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 43,644 km2 (-.4%) from previous day.
Down 317,590 km2  (-2.84%) over past seven days (daily average: -45,370 km2).
Down 1,413,128 km2  (-11.55%) for May (daily average: -61,440 km2).
1,126,654 km2 below 2000s average for this date.
708,050 km2 below 2010s average for this date.
436,128 km2 below 2015 value for this date.
1,007,308 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 23 May) average.
Lowest May to-date average.
Lowest value for the date.
89 days this year (62.24% year-to-date) have recorded the lowest daily extent.
27 days (18.88%) have recorded the second lowest.
14 days (9.79%) have recorded the third lowest.
130 days in total (90.91%) have been among the lowest three on record.


CT Area:
9,896,835 km2 (24 May [Day 0.3917])
Down 3,024,523 km2 (23.41%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
7,662,826 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 94,437 km2 (-.95%) from previous day.
Down 424,409 km2 (-4.13%) over past seven days (daily average: -60,630 km2).
Down 1,320,497 km2 (-11.86%) for May (daily average: -55,021 km2).
1,010,888 km2 below 2000s average for this date.
603,686 km2 below 2010s average for this date.
583,022 km2 below 2015 value for this date.
736,273 km2 below 2012 value for this date.
* - Due to ongoing satellite issues, multiple days in the Cryosphere Today 2016 data are missing and/or invalid; for that reason, this table incorporates sea ice area figures as calculated by Wipneus using NSIDC's numbers.



Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 24, 2016, 04:30:37 PM
Today's shadow CT-area report:

day  CT-date       NH               SH                Global
Mon 2016.3863  -25.9 10.059819   -0.4  8.423993   -26.4 18.483812
Tue 2016.3890  -68.5  9.991272  +66.9  8.490915    -1.6 18.482187
Wed 2016.3918  -94.5  9.896804  +69.8  8.560710   -24.7 18.457514
Thu 2016.3945 -119.9  9.776938  +47.6  8.608303   -72.3 18.385241

The century+ drop is brought to us by Beaufort (-21k), Chukchi(-26k), ESS(-19k) and CAB(-13k). Baffin contributed -12k.

Shadow NSIDC extent is 11.4880 (-103k3 ). Here the contributors were Okhotsk(-17k), Hudson (-14k), Beaufort (-13k)  and Bering (-12k). Baffin went up by 12k.

In the attached delta map, the broad region of concentration drop from Beaufort via Chukchi to ESS can be noticed. Perhaps a sign of surface melt.
Title: Re: 2016 sea ice area and extent data
Post by: Comradez on May 24, 2016, 06:17:33 PM
Sub-9 million km^2 by June 1st?  Maybe?  That would be insane. 

Even at 9.5 mil by June 1st, we gotta figure:
*June is good for a 2.5 mil drop.
*July is good for a 2.5 mil drop.
*August is good for a 1.5 mil drop. 

That would already bring us down to 2.5 million km^2 for Sept. 1st. 
Title: Re: 2016 sea ice area and extent data
Post by: AmbiValent on May 24, 2016, 06:48:52 PM
Area is not uniformly lost, it depends on how thick the ice is in that area. So you can't really look at past years and assume the same area would be lost.

That being said, right now it looks to me like the multi-year ice is mostly safe while the first-year ice is being threatened by melt sooner or later this year. (While in 2012, the heat had to melt a bunch of multi-year ice to get to the record)
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on May 24, 2016, 08:43:27 PM
Sub-9 million km^2 by June 1st?  Maybe?  That would be insane. 

Even at 9.5 mil by June 1st, we gotta figure:
*June is good for a 2.5 mil drop.
*July is good for a 2.5 mil drop.
*August is good for a 1.5 mil drop. 

That would already bring us down to 2.5 million km^2 for Sept. 1st.
Reasonable assumptions, but I will be very surprised if we pass 10 million km2 by June 1.  If similar weather continues in June, we could easily see over 2.5 million km2 of melt in both June and July, and potentially almost 2 million in August.  It's going to be about the momentum - additional heat picked up early amplifying later melt.
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on May 24, 2016, 08:45:35 PM
Sub-9 million km^2 by June 1st?  Maybe?  That would be insane. 

Even at 9.5 mil by June 1st, we gotta figure:
*June is good for a 2.5 mil drop.
*July is good for a 2.5 mil drop.
*August is good for a 1.5 mil drop. 

That would already bring us down to 2.5 million km^2 for Sept. 1st.
Reasonable assumptions, but I will be very surprised if we pass 10 million km2 by June 1.  If similar weather continues in June, we could easily see over 2.5 million km2 of melt in both June and July, and potentially almost 2 million in August.  It's going to be about the momentum - additional heat picked up early amplifying later melt.
We are already at 9.77M KM2...
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on May 24, 2016, 08:48:46 PM
Sub-9 million km^2 by June 1st?  Maybe?  That would be insane. 

Even at 9.5 mil by June 1st, we gotta figure:
*June is good for a 2.5 mil drop.
*July is good for a 2.5 mil drop.
*August is good for a 1.5 mil drop. 

That would already bring us down to 2.5 million km^2 for Sept. 1st.
Reasonable assumptions, but I will be very surprised if we pass 10 million km2 by June 1.  If similar weather continues in June, we could easily see over 2.5 million km2 of melt in both June and July, and potentially almost 2 million in August.  It's going to be about the momentum - additional heat picked up early amplifying later melt.
We are already at 9.77M KM2...
ADS-NPR extent is at 10.8 as shown above.  What measure are we looking at?

[edit: AH, you were speaking of area, not extent.  My mistake.  Yes, sub 9.5 by 6/1 is very probable if not impossible to avoid.]
Title: Re: 2016 sea ice area and extent data
Post by: Tealight on May 24, 2016, 11:14:14 PM
I think 2016 will defenitly set a new record low for average sea ice area this year. Currently we are 250,000 km2 below the previous record and it seems to be increasing further.

Year    million km2
2007   12.38
2011   12.26
2012   12.68
2015   12.40
2016   12.01
Title: Re: 2016 sea ice area and extent data
Post by: DavidR on May 25, 2016, 12:59:35 AM
Sub-9 million km^2 by June 1st?  Maybe?  That would be insane. 

Even at 9.5 mil by June 1st, we gotta figure:
*June is good for a 2.5 mil drop.
*July is good for a 2.5 mil drop.
*August is good for a 1.5 mil drop. 

That would already bring us down to 2.5 million km^2 for Sept. 1st.
Average melt over the last 10 years to June 1st  is 665K km^2 taking area to 9.1 M.
Three years take area below 9M and 2014 melt takes it  down to 8.8. So its definitely doable.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 25, 2016, 01:56:24 PM
ADS-NIPR Extent:
10,792,665 km2 (24 May)
Down 3,149,842 km2 (22.59%) from 2016 maximum of 13,942,507 km2 on 29 February.
7,615,210 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 87,654 km2 (-.81%) from previous day.
Down 352,054 km2  (-3.16%) over past seven days (daily average: -50,293 km2).
Down 1,500,782 km2  (-12.27%) for May (daily average: -62,533 km2).
1,165,979 km2 below 2000s average for this date.
737,015 km2 below 2010s average for this date.
482,997 km2 below 2015 value for this date.
1,053,737 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 24 May) average.
Lowest May to-date average.
Lowest value for the date.
90 days this year (62.5% year-to-date) have recorded the lowest daily extent.
27 days (18.75%) have recorded the second lowest.
14 days (9.72%) have recorded the third lowest.
131 days in total (90.97%) have been among the lowest three on record.


CT Area:
9,776,938 km2 (25 May [Day 0.3945])
Down 3,144,420 km2 (24.34%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
7,542,929 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 119,866 km2 (-1.21%) from previous day.
Down 511,040 km2 (-5.%) over past seven days (daily average: -73,006 km2).
Down 1,440,394 km2 (-12.93%) for May (daily average: -57,616 km2).
1,043,275 km2 below 2000s average for this date.
670,951 km2 below 2010s average for this date.
707,050 km2 below 2015 value for this date.
822,586 km2 below 2012 value for this date.
Lowest year-to-date (Day 0.0000 - Day 0.3945) average.
Lowest May to-date average.
Lowest value for the date.
* - Due to ongoing satellite issues, multiple days in the Cryosphere Today 2016 dataset are missing and/or invalid; for that reason, this table incorporates sea ice area figures as calculated by Wipneus using NSIDC's numbers. (Thanks, Wipneus!)



Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 25, 2016, 02:29:17 PM
As a note of comparison: were the rest of the 2016 melt season to progress exactly as the 2007 melt season, 2016 SIA would drop below the previous 2012 record for a total of 32 days; were it to follow 2012's trajectory, it would spend a whopping 50 days below the previous record, bottoming out at 1.41 million km2.

Similarly, for sea ice extent, a repeat of 2007's trajectory would see 2016 spending 17 days below the 2012 record, while a repeat of 2012 would also see 2016 spend a full 50 days below the existing record, reaching a nadir of 2.12 million km2.

Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 25, 2016, 04:20:52 PM
Shadow CT-area report:

day  CT-date       NH               SH                Global
Tue 2016.3890  -68.5  9.991272  +66.9  8.490915    -1.6 18.482187
Wed 2016.3918  -94.5  9.896804  +69.8  8.560710   -24.7 18.457514
Thu 2016.3945 -119.5  9.777306  +47.7  8.608370   -71.8 18.385676
Fri 2016.3973  -63.8  9.713479  +71.0  8.679335    +7.1 18.392814

CAB (-19k), Kara (-14k) and Baffin (-14k) have the largest area drops.

Shadow NSIDC extent is now: 11.4006 ( -87k5). Baffin (-29k), Bering (-20k) and Beaufort (-16k) dropped most in extent.

In the delta map the concentration drop near the Pole that was noticed in the "homebrew" thread is also seen by the F18 satellite and Nasa Team algorithm.
Title: Re: 2016 sea ice area and extent data
Post by: AmbiValent on May 25, 2016, 04:35:22 PM
Hm... in Wipneus' post 2016.3945 means Thursday, in Jim Pettit's it means Wednesday. Which is it?
Title: Re: 2016 sea ice area and extent data
Post by: dnem on May 25, 2016, 04:48:44 PM
I'd guess the confusion is related to counting leap day (or not).

FWIW, I did something similar to what Jim did above.  A appended 2012 losses on to the current ADS-NIPR extent and confirm his minimum of 2.12 km^2.  I also appended average losses for the three years with the lowest minima (2012, 2007 and 2015) onto the current extent and the result looks a lot like 2012 overall with a minimum of 3.05 km^2.  I also appended the average loses of the three highest minima years since 2007 (2009, 2013 and 2014) onto the current extent.  That (highly unlikely) scenario would bring us to a minimum around 3.89 km^2 this fall.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 25, 2016, 06:31:30 PM
Blame Cryosphere Today's day numbering. Thursday means the day of CT's data release, 2016.3945 is the date they will tag it with. But the ice concentration measure on Monday!

If that is confusing, the latest data (using yesterday's satellite measurements) is the last line in the report.
Title: Re: 2016 sea ice area and extent data
Post by: Lord M Vader on May 25, 2016, 06:39:42 PM
Speaking about Cryosphere Today, seems like they have gone bananas again.. Just look at those ridiculous numbers!
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 25, 2016, 08:16:55 PM
I long ago went with the Cryosphere Today method of simply ignoring the leap day (which shifted from leap year to leap year), mostly because it made it easier to align year-over-year graphs, and because the leap day conveniently falls near the annual maximum plateau. To maintain consistency across the different datasets I track and graph since then, I've stuck by that method for all metrics: extent, volume, temperature data, etc. Apologies for any confusion, but any method for dealing with leap years is going to cause issues somewhere. At any rate, that's yet another reason why year-to-year comparisons aren't really meaningful: noting that, for example, extent dropped by 30k today but went up by 30k on the same day last year is far less germane than noting that extent dropped by, say, 2 million this month and went up by two million the same month last year.
Title: Re: 2016 sea ice area and extent data
Post by: Buddy on May 26, 2016, 01:23:29 PM
Quote
Down 3,149,842 km2 (22.59%) from 2016 maximum of 13,942,507 km2 on 29 February

I LOVE this weekly summary of ice that Jim Pettit does.  It gives us a "good look" against various other "yard sticks" to compare.

One way to look at 2016 is this:  We have burned through 3.15 million square kilometers of ice so far this year.  What is the amount of ice that we had burned through in 2012 (from peak ice that year to this date)?

I can "kind of eyeball" it on a chart....and it looks like we have burned through more ice (maybe about 500,000 more 2K).  But Jim....if you DO have the numbers.....I would be curious to know:  The absolute square kilometers burned through for 2012 from peak to May 25th of that year.

We know that 2016 is 1.054 million square kilometers below 2012.....but 2012 started at a much higher winter maximum (eyeballing it.....maybe 500,000 above the 2016 maximum).

Thanks.....

Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 26, 2016, 02:16:11 PM
One way to look at 2016 is this:  We have burned through 3.15 million square kilometers of ice so far this year.  What is the amount of ice that we had burned through in 2012 (from peak ice that year to this date)?

I can "kind of eyeball" it on a chart....and it looks like we have burned through more ice (maybe about 500,000 more 2K).  But Jim....if you DO have the numbers.....I would be curious to know:  The absolute square kilometers burned through for 2012 from peak to May 25th of that year.

We know that 2016 is 1.054 million square kilometers below 2012.....but 2012 started at a much higher winter maximum (eyeballing it.....maybe 500,000 above the 2016 maximum).

Certainly. If my early morning math is correct:

2012 extent topped out at 14,709,086 km2 on 7 March
2016 extent topped out at 13,942,507 km2 on 29 February
Difference: 766,579 km2

On May 25, 2012, SIE stood at 11,797,276 km2, a loss from maximum of 2,911,810 km2, or 36,858 km2 per day.
On May 25, 2016, SIE stands at 10,704,953 km2, a loss from maximum of 3,237,554 km2, or 37,646 km2 per day.

So: very similar loss per day numbers, with the slight edge to 2016. Which doesn't sound too astounding until one considers that 2012 likely had more "easy" ice to lose in the first place.

FWIW, 2012 hit its first (and perhaps steepest) "cliff" on 5 June; that kicked off a ten-day spree of decrease that averaged 119k per day, and included seven consecutive century drops. It'll be interesting to see, then, how much of the current 2012-2016 spread disappears over the next three weeks. Some? Most? All?
Title: Re: 2016 sea ice area and extent data
Post by: timallard on May 26, 2016, 02:31:46 PM
Newbie questions & such, is there buoy data at depths for water temps & ‰ with location to use with the colored thickness maps?

Is it considered needed to have a new official category of ice, "rotten"? Some was cored last fall, the multi-year ice part of rafts left in fall looked rotten like parts of a glacier melting down get.

And noting that freeze-up is now pancake ice everywhere a change from prior eras what does that mean?

Last fall an expedition in the Beaufort found a warm layer 20m down, a storm caused ice to form and the next day it all melted in spite of low air temps from mixing that up, that to me was latent heat and that layer is there all winter.

So isn't this a new property of the fresher-colder Pacific water to the prior condition, that above warmer much deeper Atlantic water?

Thus my wonder is that it may thicken the surface heated layer to where it can transfer heat between the more saline layer deeper down an evolution of this?

Late April the Beaufort opened up radically, thinner than usual ice by 18% via a talk with NSIDC person posted online. An observation is that it can break up in days with a big storm any time from now on being this new type of ice, there was no big storm for the early opening this year by that talk, sequence shots: http://earthobservatory.nasa.gov/IOTD/view.php?id=88065&eocn=home&eoci=iotd_grid (http://earthobservatory.nasa.gov/IOTD/view.php?id=88065&eocn=home&eoci=iotd_grid)
Title: Re: 2016 sea ice area and extent data
Post by: Buddy on May 26, 2016, 03:14:58 PM
Jim...thanks for getting those numbers.

Quote
2012 extent topped out at 14,709,086 km2 on 7 March
2016 extent topped out at 13,942,507 km2 on 29 February
Difference: 766,579 km2

So....the melt year started out with 2016 having a 766,579 lead on 2012.  And now that lead has grown to 1,053,737 (an additional gain of 287,158 km2 from the peak).

Not surprisingly this would "seem" to support the fact that the ice is MUCH more vulnerable now because of its LACK of thickness.  Even though 2012 started out with what was quite likely a lot of "first year ice"......2016 has INCREASED its lead over 2012 by a fairly substantial amount.

And...I agree with you Jim.....the next few weeks or so could be quite interesting.

I do "believe" that 2016 will continue to "track in parallel fashion" 2012.....keeping its "lead" in tact...and that lead will GROW...especially when we get into late July and into August.



Title: Re: 2016 sea ice area and extent data
Post by: DavidR on May 26, 2016, 03:38:33 PM

So: very similar loss per day numbers, with the slight edge to 2016. Which doesn't sound too astounding until one considers that 2012 likely had more "easy" ice to lose in the first place.

FWIW, 2012 hit its first (and perhaps steepest) "cliff" on 5 June; that kicked off a ten-day spree of decrease that averaged 119k per day, and included seven consecutive century drops. It'll be interesting to see, then, how much of the current 2012-2016 spread disappears over the next three weeks. Some? Most? All?

2012 didn't really have much more easy ice to lose than 2016. It did have a lot more ice in the Pacific but most of that was gone by June 1.

The figure below provides an estimate of the area of ice for various mean thicknesses in the PIOMAS April data.  As can be seen, for most of this period 2012 and 2016 have the same amount of ice despite 2016 starting with 800K km^2 less. 

According to  my  estimate 2016 is currently sitting in the 0.95 m panel for amount of area gone and 2012 is in the 0.85 column.  Based on this I am estimating that  2012 won't even close the gap much with 2016 in the next three weeks. and by June 16th 2016 will still be 800K km^2  below 2012.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 26, 2016, 04:14:08 PM
2012 didn't really have much more easy ice to lose than 2016. It did have a lot more ice in the Pacific but most of that was gone by June 1.

Well, that's the "easy" ice to which I was referring.

At any rate, if you're correct in your estimation, things are going to get very, er, interesting come July and August...
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 26, 2016, 04:35:28 PM
Shadow CT-area report:

day  CT-date       NH               SH                Global
Wed 2016.3918  -94.5  9.896804  +69.8  8.560710   -24.7 18.457514
Thu 2016.3945 -119.5  9.777306  +47.7  8.608370   -71.8 18.385676
Fri 2016.3973  -63.8  9.713496  +71.0  8.679335    +7.2 18.392831
Sat 2016.4000  -66.1  9.647368  +27.5  8.706805   -38.7 18.354173

Baffin dropped -15k, Hudson, Kara and Beaufort each about -11k. ESS increased +16k.

Shadow NSIDC was 11.3791 ( -21.9k). Hudson changed most at -15k.

Attached delta map gives you another look . For instance the open water in the top of Baffin Bay looks big and is growing.
Title: Re: 2016 sea ice area and extent data
Post by: Yuha on May 26, 2016, 08:13:36 PM
FWIW, 2012 hit its first (and perhaps steepest) "cliff" on 5 June; that kicked off a ten-day spree of decrease that averaged 119k per day, and included seven consecutive century drops. It'll be interesting to see, then, how much of the current 2012-2016 spread disappears over the next three weeks. Some? Most? All?

My rough guess: The 2012-2016 difference is now about 1.1M, by June 4 just before the cliff it will be about 900k, and by June 14 at the end of the cliff, it will be about 500k.

The guess is based on looking at Wipneus' regional graphs at the Arctic Sea Ice Graphs page (https://sites.google.com/site/arcticseaicegraphs/regional). The biggest contributor to the reduction in the difference is Bering Sea which still had about 400k of easy ice left at this time in 2012. The error margins are big though as many regions are dropping fast and just a couple of days difference in timing can mean a big difference in the extent.
Title: Re: 2016 sea ice area and extent data
Post by: Paddy on May 26, 2016, 08:54:50 PM
I am no expert, but surely what will make the difference is what happens in the central Arctic Basin? Most other areas can be expected either to become ice free, as they have in most recent years, or to hold onto a little bit of tough multi-year / calved ice. But it's in the CAB that 2012 was different
.. and what I'm wondering is what happens if we see an early start to the melt there?
Title: Re: 2016 sea ice area and extent data
Post by: Neven on May 26, 2016, 10:25:58 PM
snip

Don't ask questions that aren't tied directly to sea ice area and extent data in this thread. Ask in the buoy thread.
Title: Re: 2016 sea ice area and extent data
Post by: Pmt111500 on May 27, 2016, 06:49:17 AM
snip

Don't ask questions that aren't tied directly to sea ice area and extent data in this thread. Ask in the buoy thread.

Yes, that's more of a volume thing anyway. At least I've come to avoid those threads that contain much something else than what's related to the topic. That said, will there be the June drop due the melt ponds this year too, now that CT is having issues? Is it seen in the Wipneus' numbers of area?
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 27, 2016, 01:07:19 PM
ADS-NIPR Extent:
10,652,073 km2 (26 May)
Down 3,290,434 km2 (23.6%) from 2016 maximum of 13,942,507 km2 on 29 February.
7,474,618 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 52,880 km2 (-.49%) from previous day.
Down 389,153 km2  (-3.52%) over past seven days (daily average: -55,593 km2).
Down 1,641,374 km2  (-13.42%) for May (daily average: -63,130 km2).
1,220,829 km2 below 2000s average for this date.
763,419 km2 below 2010s average for this date.
529,970 km2 below 2015 value for this date.
1,090,443 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 26 May) average.
Lowest May to-date average.
Lowest value for the date.
92 days this year (63.01% year-to-date) have recorded the lowest daily extent.
27 days (18.49%) have recorded the second lowest.
14 days (9.59%) have recorded the third lowest.
133 days in total (91.1%) have been among the lowest three on record.


CT Area:
9,647,368 km2 (27 May [Day 0.4000])
Down 3,273,990 km2 (25.34%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
7,413,359 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 66,128 km2 (-.68%) from previous day.
Down 495,169 km2 (-4.91%) over past seven days (daily average: -70,738 km2).
Down 1,569,964 km2 (-14.1%) for May (daily average: -58,147 km2).
1,074,362 km2 below 2000s average for this date.
669,775 km2 below 2010s average for this date.
656,014 km2 below 2015 value for this date.
786,521 km2 below 2012 value for this date.
Lowest value for the date.
NOTE: due to the prolonged absence of official CT sea ice area data, I'm instead using Wipneus' calculated area numbers. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!
Title: Re: 2016 sea ice area and extent data
Post by: Neven on May 27, 2016, 01:36:30 PM
Thanks, Jim. I'm using this for the first ASI update.
Title: Re: 2016 sea ice area and extent data
Post by: Buddy on May 27, 2016, 01:50:34 PM
Quote
1,090,443 km2 below 2012 value for this date.

Almost back up to the largest "spread" vs 2012 which was on the May 16th report of 1,107,XXX km2.




Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 27, 2016, 05:51:24 PM
Shadow CT-area report:

day  CT-date       NH               SH                Global
Thu 2016.3945 -119.5  9.777306  +47.7  8.608370   -71.8 18.385676
Fri 2016.3973  -63.8  9.713496  +71.0  8.679335    +7.2 18.392831
Sat 2016.4000  -66.6  9.646929  +27.5  8.706805   -39.1 18.353734
Sun 2016.4027 -100.8  9.546090  +83.4  8.790235   -17.4 18.336325

The main supporters of the century are the CAB (-40k) and Kara (-22k). Greenland Sea, Hudson and Chukchi  contribute -12k each. ESS went up by +27k.

Shadow NSIDC extent is 11.3607 a drop of "only" -18.5k.

Area dropping faster than extent, means compactness of the ice is going down. That is, if sustained, an indication that surface melting is setting in. See for instance the compactness graph:
https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-compact-compare.png

The attached delta map gives an overview.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on May 27, 2016, 06:40:18 PM
If the remainder of the 2016 melt season were to follow the trajectory of two other years in the satellite era, a new record minimum in Arctic sea ice area would be set (if not altogether shattered):

YEAR   MINIMUM    DAYS BELOW THE PREVIOUS RECORD
-------------------------------------------------------------
2007    1.97 M        43
2012    1.56 M        45

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimage.prntscr.com%2Fimage%2Fe55f04cb6dad4f4eb3b5720cebf48ba3.png&hash=70d0e1577feda72ef2664d2e3f2e5fba)

Thanks, as always, Wipneus.
Title: Re: 2016 sea ice area and extent data
Post by: Richard Rathbone on May 27, 2016, 06:56:05 PM

..., will there be the June drop due the melt ponds this year too, now that CT is having issues? Is it seen in the Wipneus' numbers of area?

Shadow CT will show it if the new satellite calibration is aligned by then. Home brew shows a much smaller melt pond effect.
Title: Re: 2016 sea ice area and extent data
Post by: Pmt111500 on May 27, 2016, 09:16:06 PM

..., will there be the June drop due the melt ponds this year too, now that CT is having issues? Is it seen in the Wipneus' numbers of area?

Shadow CT will show it if the new satellite calibration is aligned by then. Home brew shows a much smaller melt pond effect.


Thanks <Richard Rathbone>
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on May 28, 2016, 06:54:21 AM
Thank you much, Wipneus, for your continued updates on area and extent.
One quick question : In your daily maps, there are signs of losses and gains in areas that clearly do not have any more ice. Like in the Baltic, St. Lawrence, [edit] the great lakes and around Sakhalin Island.

Are these artifacts of the methods used, and do they affect the area and extent estimates you report ?
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 28, 2016, 09:06:36 AM
Thank you much, Wipneus, for your continued updates on area and extent.
One quick question : In your daily maps, there are signs of losses and gains in areas that clearly do not have any more ice. Like in the Baltic, St. Lawrence, and around [edit] Sakhalin Island.

Are these artifacts of the methods used, and do they affect the area and extent estimates you report ?

They are the consequence of the land-spill-over effect. The footprint of the microwave antenna has no sharp cut-off at the 25km gridcell boundaries and will overlap land regions. There is compensation for it, but as you see not 100% effective.

And yes they affect the area and extent numbers.

Note 1: There is always "ice" in the (great) lakes. Lake ice is never included in NSIDC extent, so that does not matter. Is IS calculated in the CT-area numbers, contributing lots of noise in the summer numbers.

Note 2: NSIDC applies ocean masks to exclude ice over regions that are guaranteed not to be covered (at the time of year) which will reduce the amount of false ice. These masks are monthly and change at the first of the month. A noticeable jump can occur at those dates, the first of June is the biggest. Wait for it, on the second we will report a century, probably double one. Since CT uses NSIDC sea ice concentration, this is also true for the first-of-the-month CT-area number yet smaller since the false ice is always low concentration.

Note 3: The NSIDC SIC data are of near-real-time quality (not to mention uncalibrated F18 satellites). After a year or so, "final" quality checked data is released (this week the final data was updated up to 2015/12/31). Some false ice will be removed in the process. Mostly not the false coastal ice, but false ice in the middle of the ocean that appears as the result of strong storms.

Title: Re: 2016 sea ice area and extent data
Post by: Andreas T on May 28, 2016, 03:14:25 PM
A while back seaice.de linked to this paper, which I was able to read in a borrowed hardcopy.
Correct, you may have a look at this one
http://www.sciencedirect.com/science/article/pii/S003442571200017X (http://www.sciencedirect.com/science/article/pii/S003442571200017X)

Tying this to the observations in the posts above, it is very likely that some changes in the microwave signal as the burst of warm, moist air passed through were temporary, some persisted. What they actually represent on the ground is probably impossible to say with certainty.
edit: sorry put my own ords in the quote box!
It compares the performance of different algorithms in dealing with changes in surface conditions such as wet and crusted snow or salinity of the ice surface.
Since the measurements of microwave emission were made at ground level weather effects were not part of that research but the paper mentions that precipitation over open water is something that needs to be filtered out because it gives the impression of ice in microwave data.

It looks like you might find this paper interesting, do you have comments on it?
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 28, 2016, 04:24:07 PM
Shadow CT-area report:

day  CT-date       NH               SH                Global
Fri 2016.3973  -63.8  9.713496  +71.0  8.679335    +7.2 18.392831
Sat 2016.4000  -66.6  9.646929  +27.5  8.706805   -39.1 18.353734
Sun 2016.4027 -100.9  9.546027  +83.4  8.790166   -17.5 18.336193
Mon 2016.4055  -19.3  9.526709  +37.7  8.827913   +18.4 18.354622

A relatively small drop in area overall. Regionally there are interesting differences. The CAB dropped -34k with Hudson at -19k  second. But Laptev and ESS went up by +15k and +12k.

Shadow NSIDC is now 11.2849  (-76.4k). Barents (-24k), CAB (-18k), StLawrence (-15k) and Greenland Sea (-14k) did contribute. The uptick in Hudson (+22k) contrasts with the simultaneous drop in area.

The attached delta map shows where the changes are taking place actually.


Title: Re: 2016 sea ice area and extent data
Post by: Shared Humanity on May 28, 2016, 06:05:32 PM
Looking at this image and from a completely uninformed point of view, it seems to suggest that a large portion of the Atlantic side of the CAB is moving towards the Fram.
Title: Re: 2016 sea ice area and extent data
Post by: Laurent on May 28, 2016, 07:01:56 PM
The exit to Fram doesn't seem to be too fast for the moment :
http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticicespddrf_nowcast_anim30d.gif (http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticicespddrf_nowcast_anim30d.gif)

It is easier to see with the thickness map :
http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn_nowcast_anim30d.gif (http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn_nowcast_anim30d.gif)
Title: Re: 2016 sea ice area and extent data
Post by: Eli81 on May 28, 2016, 10:19:17 PM
The exit to Fram doesn't seem to be too fast for the moment :

It is easier to see with the thickness map :
http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn_nowcast_anim30d.gif (http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn_nowcast_anim30d.gif)
If anything it looks almost completely stalled, especially the last week or so... It's just sitting in the straight, melting...

Is that a good thing, or a bad thing?
Title: Re: 2016 sea ice area and extent data
Post by: Laurent on May 28, 2016, 11:18:40 PM
It is normal, the Beaufort gyre is attracting the whole Arctic ice, that does happen in cycle, some release, some stall (depends of the winds also). if we want the ice to be preserved, it'd better stay there, once passed the Fram, it is chao bye bye the ice... well that was before when the Atlantic wasn't in the Arctic. Now that it is in, I think the melting is going on, we are not seeing it yet clearly at Svalbard level but it is. Let's look at it !
Title: Re: 2016 sea ice area and extent data
Post by: timallard on May 29, 2016, 04:05:00 PM
It is normal, the Beaufort gyre is attracting the whole Arctic ice, that does happen in cycle, some release, some stall (depends of the winds also). if we want the ice to be preserved, it'd better stay there, once passed the Fram, it is chao bye bye the ice... well that was before when the Atlantic wasn't in the Arctic. Now that it is in, I think the melting is going on, we are not seeing it yet clearly at Svalbard level but it is. Let's look at it !
A bit off topic, the Atlantic flow circulation is abetted by having Bering Strait open.

The bathtub test: You have a hose, the Pacific is adding water and if you place the hose off center it causes a circulation. Turn off the hose, the circulation fades to nothing.

That's the analog, 1-sverdrup of current causes more inflow by the Atlantic from the circulation it causes thus to deal with the Atlantic water upwelling consider this.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 29, 2016, 04:21:13 PM
The shadow CT-area report:

day  CT-date       NH               SH                Global
Sat 2016.4000  -66.6  9.646929  +27.5  8.706805   -39.1 18.353734
Sun 2016.4027 -100.9  9.546027  +83.4  8.790166   -17.5 18.336193
Mon 2016.4055  -19.3  9.526734  +37.5  8.827632   +18.2 18.354366
Tue 2016.4082  -25.6  9.501168  -45.2  8.782450   -70.7 18.283618

Like yesterday, regions differ greatly. CAB dropped -39k while Greenland Sea (+23k) and Hudson (+13) went up.

Shadow NSIDC was 11.2665, dropping just  -18.4k. CAB (-18k) Okhotsk (-14) and Hudson (-13k) went down. Little plusses in many other regions.

Attached delta map visualizes the numbers.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on May 30, 2016, 10:35:17 AM
Update for the week to May 28th

The current 5 day trailing average is on 11,338,000km2 while the 1 day extent is at 11,267,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,514,000km2, an increase from -1,481,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -1,021,000km2, a decrease from -1,035,000km2 last week. We're currently the lowest on record, the same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FugIqG1Z.png&hash=ac922cf72fabe86fb287c83bd63f7aaf)

The average daily change over the last 7 days was -46.7k/day, compared to the long term average of -42.1k/day, and the 07, 11 and 12 average of -48.7k/day.
The average long term change over the next week is -55.8k/day, with the 07, 11, and 12 average being -56.0k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FviZAFSE.png&hash=a20b54eb89adecf64f4b6248a895509f)

The extent drop so far this May is the 2nd largest on record. To achieve the largest monthly loss, a drop of at least 110.0k/day is required (requiring >218k/day with with daily values), while the smallest loss requires an increase of at least 323.6k/day (>865k/day with single day values) and an average loss requires a increase of 115.3k/day (>345k/day with single day values).

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FBQSZyRt.png&hash=afc8ae55d05901d4f99bc23d7be2b5af)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 30, 2016, 04:11:49 PM
Shadow CT-area report:

day  CT-date       NH               SH                Global
Sun 2016.4027 -100.9  9.546027  +27.5  8.706805   -73.4 18.252832
Mon 2016.4055  -19.3  9.526734  +83.4  8.790166   +64.1 18.316900
Tue 2016.4082  -25.6  9.501086  +37.5  8.827632   +11.8 18.328718
Wed 2016.4110  -70.5  9.430610  -45.2  8.782450  -115.7 18.213060

Find the strongest declines in the ESS (-30k) and  Chukchi (-16k). Greenland Sea dropped -14k.

Shadow NSIDC is now 11.2092  a drop of -56.8k. In extent Baffin (-21) and StLawrence (-14k) lead the pack.

The attached delta map shows in detail where the largest changes are.
Title: Re: 2016 sea ice area and extent data
Post by: Tor Bejnar on May 30, 2016, 06:09:36 PM
BFTV's "Melt Season 7 Day Extent Loss" graph (posted earlier today) shows that 2012 extent loss, starting in about a week, set a significant record for loss.  2012 also set a new record (for the day-of year) for about a week in August.  Interestingly, 2016, despite it being so far ahead of all other years in having the lowest extent for-the-day, has set the record fast extent loss for-the-day-of-year (since April 1) for only a few days in mid-May, and only just barely so.
Title: Re: 2016 sea ice area and extent data
Post by: seaicesailor on May 30, 2016, 07:39:18 PM
Update for the week to May 28th
... while the smallest loss requires an increase of at least 323.6k/day (>865k/day with single day values) ...

According to CFSv2 this is the most probable scenario
Title: Re: 2016 sea ice area and extent data
Post by: Nick_Naylor on May 30, 2016, 07:51:18 PM
The extent drop so far this May is the 2nd largest on record. To achieve the largest monthly loss, a drop of at least 110.0k/day is required (requiring >218k/day with with daily values) . . .
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FBQSZyRt.png&hash=afc8ae55d05901d4f99bc23d7be2b5af)
BFTV - This new specificity regarding the 5-day averages vs. the daily values definitely helps me understand which values you are providing - thanks!
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on May 31, 2016, 04:17:27 PM
Shadow CT-area report (based on uncalibrated F18 NSIDC sea ice concentration data):

day  CT-date       NH               SH                Global
Mon 2016.4055  -19.3  9.526734  +83.4  8.790166   +64.1 18.316900
Tue 2016.4082  -25.6  9.501086  +37.5  8.827632   +11.8 18.328718
Wed 2016.4110  -70.0  9.431054  -45.2  8.782425  -115.2 18.213479
Thu 2016.4137  -77.4  9.353630  +90.8  8.873200   +13.4 18.226830

That would have been a century if the CT alculation did not in clude ice on the lakes as "sea ice", lake ice went up by +24k. Laptev suddenly got active (-32k), followed by Kara (-18k), Baffin (-17k), Greenland Sea (-13k) and Chukchi (-12k). ESS bumped +15k.

Shadow NSIDC is now at 11.1573  (-51.9k). No regions are noteworthy. No lake ice in the NSIDC index fortunately.

The attached delta map shows the details.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on May 31, 2016, 04:31:31 PM
With the 5 day trailing average, the latest value is now 1.224 million km2 below 2012. This is the largest gap to 2012 this year.
However, we're approaching the June 2012 cliff where it dropped over 2 million in 20 days, so it's unlikely that we'll still be more than 1 million below 2012 by the end of the first week of June.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on June 01, 2016, 03:58:10 PM

CT Area:
9,353,630 km2 (01 June [Day 0.4137])
Down 3,567,728 km2 (27.61%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
7,119,621 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 77,424 km2 (-.82%) from previous day.
Down 423,676 km2 (-4.36%) over past seven days (daily average: -60,525 km2).
Down 77,424 km2 (-.7%) for June (daily average: -77,424 km2).
1,056,625 km2 below 2000s average for this date.
678,820 km2 below 2010s average for this date.
687,360 km2 below 2015 value for this date.
586,594 km2 below 2012 value for this date.
Lowest value for the date.
NOTE: due to the prolonged absence of official CT sea ice area data, I'm instead using Wipneus' calculated area numbers in places. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 01, 2016, 04:23:20 PM
Shadow CT-area report (based on uncalibrated F18 NSIDC sea ice concentration data):

day  CT-date       NH               SH                Global
Tue 2016.4082  -25.6  9.501086  -45.2  8.782425   -70.9 18.283511
Wed 2016.4110  -70.0  9.431054  +90.9  8.873280   +20.8 18.304334
Thu 2016.4137  -76.8  9.354228 +137.7  9.010970   +60.9 18.365198
Fri 2016.4164  -31.8  9.322383 +187.7  9.198683  +155.9 18.521066

While the CAB had a big "recovery" of +38k, Laptev dropped almost as much -36k. Further only Kara can be noted at -14k.

Shadow NSIDC extent is now 11.0969  dropping -60.4k. Baffin, Kara and okhotsk are the biggest contributors: -22k, -18k and -15k. Greenland Sea went up by +22k.

Tomorrow I expect to report the first of the month numbers, in June this guarantees big drops as lots of false ice will be masked out. Looking at the numbers I expect 80-150k of extra extent loss.

The attached delta map shows the details.
Title: Re: 2016 sea ice area and extent data
Post by: Nick_Naylor on June 01, 2016, 09:25:34 PM
Tomorrow I expect to report the first of the month numbers, in June this guarantees big drops as lots of false ice will be masked out. Looking at the numbers I expect 80-150k of extra extent loss.

I assume the extra 80-150k all comes in the June 1 number, or is it phased in?
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on June 01, 2016, 09:47:48 PM
The average daily drop from May 31st to June 1st is 138k. These range from small 24k drop in 1987 to a max drop of 244k in 1990.
Only one drop in the last 27 years was small enough to prevent 2016 from being below 11 million km2 on June 1st.
Title: Re: 2016 sea ice area and extent data
Post by: abbottisgone on June 02, 2016, 07:52:22 AM
The average daily drop from May 31st to June 1st is 138k. These range from small 24k drop in 1987 to a max drop of 244k in 1990.
Only one drop in the last 27 years was small enough to prevent 2016 from being below 11 million km2 on June 1st.
I think the number given in espens thread for june 1 was very low: sub 30k.

The preceding few days were circa 50k so I suppose this is almost typical pause-like behaviour which seems to be normal at this exact time as seen by my grossly amatuer involvement thus far!
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 02, 2016, 08:41:08 AM

I think the number given in espens thread for june 1 was very low: sub 30k.

The preceding few days were circa 50k so I suppose this is almost typical pause-like behaviour which seems to be normal at this exact time as seen by my grossly amatuer involvement thus far!

It is probably nothing to do with the ice. On 1st of June Jaxa changes the tie points of the Bootstrap algorithm from "dry ice" to "wet ice" (some wrongly interpret this as melt pond compensation).
The change takes a few days, so expect some more slow days.

You can observe this on my AMSR2 extent graph.  Until today, Jaxa and UH (black and purple lines) follow each other closely. Between 1 June and 15 October expect Jaxa extent to stay above Uni Hamburg extent.

Edit: To be extra clear, this is an ADS-Jaxa SIC thing, no such effect in data from other sources.

(https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-extent-all-cmpare.png)

LINK (https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-extent-all-cmpare.png)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on June 02, 2016, 02:03:56 PM
ADS-NIPR Extent:
10,405,086 km2 (01 June)
Down 3,537,421 km2 (25.37%) from 2016 maximum of 13,942,507 km2 on 29 February.
7,227,631 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 21,958 km2 (-.21%) from previous day.
Down 299,867 km2  (-2.8%) over past seven days (daily average: -42,838 km2).
Down 21,958 km2  (-.18%) for June (daily average: -21,958 km2).
1,218,364 km2 below 2000s average for this date.
717,414 km2 below 2010s average for this date.
440,699 km2 below 2015 value for this date.
1,038,112 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 01 June) average.
Lowest value for the date.
98 days this year (64.47% year-to-date) have recorded the lowest daily extent.
27 days (17.76%) have recorded the second lowest.
14 days (9.21%) have recorded the third lowest.
139 days in total (91.45%) have been among the lowest three on record.


CT Area:
9,322,383 km2 (02 June [Day 0.4164])
Down 3,598,975 km2 (27.85%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
7,088,374 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 31,845 km2 (-.34%) from previous day.
Down 391,113 km2 (-4.05%) over past seven days (daily average: -55,873 km2).
Down 108,671 km2 (-.98%) for June (daily average: -54,335 km2).
1,032,736 km2 below 2000s average for this date.
643,823 km2 below 2010s average for this date.
750,309 km2 below 2015 value for this date.
556,003 km2 below 2012 value for this date.
Lowest value for the date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' area numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!



Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 02, 2016, 05:02:55 PM
Shadow CT-area report (based on uncalibrated F18 NSIDC sea ice concentration data):

day  CT-date       NH               SH                Global
Wed 2016.4110  -70.0  9.431054  +90.9  8.873280   +20.8 18.304334
Thu 2016.4137  -76.8  9.354228 +137.7  9.010970   +60.9 18.365198
Fri 2016.4164  -32.1  9.322127 +187.9  9.198832  +155.8 18.520959
Sat 2016.4192  -21.9  9.300189 +160.8  9.359640  +138.9 18.659829

Increases in Laptev(+18k) and Baffin (+15). Area dropped in St-Lawrence (-11) and in regions not one of the 14 well known ones (-20k).

Shadow NSIDC extent is 10.9977  (-98.2k) . Here the drops in St-Lawrence and Other Regions are much bigger: -32k and -40k.

As explained yesterday, those drops are caused by the first of the month effect. Without it we would have had a very small decrease in extent an perhaps a positive change in area.

The attached delta map shows the details.
Title: Re: 2016 sea ice area and extent data
Post by: Tor Bejnar on June 02, 2016, 08:28:49 PM
"those drops are caused by the first of the month effect."
How can there be any blue on the Great Lakes - that is, ice growth between May 31 and June 1 if a mask now prevents false ice showing up there.  Just to make sure - there is no ice on the Great Lakes now, right?  (I know there was some ice on Lake Superior until June 5 or 6, 2014.)
Title: Re: 2016 sea ice area and extent data
Post by: LRC1962 on June 02, 2016, 08:39:50 PM
Based on this:(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.glerl.noaa.gov%2Fres%2Fglcfs%2Fncast%2Fsswt-00.gif&hash=8e1737f06945ee53ffa070d6833714a6)
Do not think possible. Highly unlikely for some time.
Edit: Based on animation: http://www.glerl.noaa.gov/res/glcfs/anim.php?lake=l&param=glsea&type=n (http://www.glerl.noaa.gov/res/glcfs/anim.php?lake=l&param=glsea&type=n)
May the 4th was last day of ice.
Title: Re: 2016 sea ice area and extent data
Post by: Magma. on June 02, 2016, 09:53:40 PM
"those drops are caused by the first of the month effect."
How can there be any blue on the Great Lakes - that is, ice growth between May 31 and June 1 if a mask now prevents false ice showing up there.  Just to make sure - there is no ice on the Great Lakes now, right?  (I know there was some ice on Lake Superior until June 5 or 6, 2014.)

According to regional charts, the last scraps of ice in sheltered bays on the central north Canadian side of Lake Superior melted out just after May 6.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on June 02, 2016, 10:46:32 PM
Despite what was only the 3rd sub 100k drop for June 1st since 1990, NSIDC daily extent is now below 11 million km2. This is 10 days earlier than the previous record holders 2012 and 2010, which both reached dropped below 11 million km2 on June 11th.
Title: Re: 2016 sea ice area and extent data
Post by: Yazzur on June 03, 2016, 01:27:19 AM
"those drops are caused by the first of the month effect."
How can there be any blue on the Great Lakes - that is, ice growth between May 31 and June 1 if a mask now prevents false ice showing up there.  Just to make sure - there is no ice on the Great Lakes now, right?  (I know there was some ice on Lake Superior until June 5 or 6, 2014.)
Title: Re: 2016 sea ice area and extent data
Post by: Yazzur on June 03, 2016, 01:32:22 AM
There is no ice on the Great Lakes as of last weekend, and it is well above freezing.
Title: Re: 2016 sea ice area and extent data
Post by: ktonine on June 03, 2016, 03:43:19 AM
A few years back I investigated some of the coastal anomalies in SIE -- patches of ice where there hadn't been any for days or weeks that just popped up out of nowhere for no apparent reason.

Checking many of these with MODIS I found that many of them were sandy coastal stretches.  I think sunlight on wet sand was confusing the sensors.  Not sure if a similar effect is happening on the Great Lakes, but regardless, sensors aren't perfect and there are numerous conditions that might give very similar reflections.  It's one of the reasons why SIE has such a large uncertainty.  It's nothing more than a curiosity.
Title: Re: 2016 sea ice area and extent data
Post by: ghoti on June 03, 2016, 03:53:39 AM
Great Lakes really should be masked out because it is absurd to even consider the possibility of ice in the spring/summer/fall now.

Look at the lake temperatures...

http://www.mlive.com/weather/index.ssf/2016/05/all_great_lakes_warmer_than_la.html (http://www.mlive.com/weather/index.ssf/2016/05/all_great_lakes_warmer_than_la.html)

Title: Re: 2016 sea ice area and extent data
Post by: S.Pansa on June 03, 2016, 07:02:40 AM
Ad great lakes. I don't think that they are included, at least not in the NSIDC numbers. To quote Wipneus himself from last years thread (https://forum.arctic-sea-ice.net/index.php/topic,1112.msg55713.html#msg55713):
Quote
A repeat seems in order about lake ice.

CT-area and NSIDC extent are based on the same data, available as NSIDC gridded sea ice concentration data.

NSIDC does not include in its calculation ice detected in lakes, so there is no need to filter that says "No lake ice in July". In the ocean it _is_ filtered, so there will be "No ice in St. Lawrence" for example.

CT-area does include lake ice and also does not filter anything unless NSIDC has filtered it already.

This is only one of the deficiencies (my judgement) of the CT-area figures. But is a popular measure so I add some additional information about it. That is report it timely, summarize the regional deviations and note obvious "false" changes, like (dis)appearance of "lake ice".

By the way: Thanks Wipneus for all the infos you provide day by day! Much aprecciated.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 03, 2016, 07:46:40 AM
Thank you, S.Pansa, your post saves me repeating myself again.

Just this:

- There are ocean masks, that do not mask lakes because (I think) lakes are not oceans; There are 12 ocean masks, one for each month;
- There is a lake mask, NSIDC pays attention, CT does not. There is only one for the whole year;
- The NSIDC ocean masks are used by other sources of sea ice concentration. Uni Hamburgs ice concentration and from OSI-SAF are known to me. Impact on UH area and extent (home brew thread) is small, as there is far less false ice due to the higher resolution of the used satellite microwave measurements.
Title: Re: 2016 sea ice area and extent data
Post by: Tor Bejnar on June 03, 2016, 05:19:05 PM
Thanks.  Is the following correct?
NSIDC: always a lake mask (regardless of what the blue/red change maps show)  Seashore masks change each month (but you don't know what they are by looking at the blue/red change maps)
CT: never a lake or sea mask (therefore responsive to data that shows up on the blue/red change maps)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 03, 2016, 05:57:39 PM
Thanks.  Is the following correct?
NSIDC: always a lake mask (regardless of what the blue/red change maps show)  Seashore masks change each month (but you don't know what they are by looking at the blue/red change maps)
CT: never a lake or sea mask (therefore responsive to data that shows up on the blue/red change maps)

"seashore maks" are called ocean masks. The effect they have is not just on the coastal ice but also on the open ocean (e.g. due to high waves from storms). They are applied to the gridded sea ice concentration data before they are distributed. So all users of that data used the masked values, including CT.

NSIDC did choose not to mask out any lake ice in their gridded sea ice concentration product. So it depends on the user of the data to do with the "lake ice". There is a mask though that says, this is land or ocean or lake. That can be used to include only grid cells that cover ocean. CT did choose to use grid cells that cover ocean or lake. 

Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 03, 2016, 06:06:57 PM
No new data from NSIDC yet. What they have done is to remove the F18_uncalibrated directory and mixed the F18 data files in the normal place with F17 files (upto 2016/03/31).
So I hope that calibration is soon a fact.

Not bad. I updated my computer with new processor, mother board and memory today. Bad thing is that my high resolution screen (2048x1152) is not recognized and I have to work on a far too small thing. Software install is another thing, that may take days before everything is OK again.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 03, 2016, 07:00:50 PM
NSIDC gridded SIC data is in.
Shadow CT-area report (based on F18 NSIDC sea ice concentration data, we don't know if it is calibrated):

day  CT-date       NH               SH                Global
Thu 2016.4137  -76.8  9.354228 +137.7  9.010970   +60.9 18.365198
Fri 2016.4164  -32.1  9.322127 +187.9  9.198832  +155.8 18.520959
Sat 2016.4192  -22.0  9.300101 +160.8  9.359640  +138.8 18.659741
Sun 2016.4219 -156.7  9.143387 +100.4  9.460078   -56.3 18.603465

One century and a half, big drops in CAB (-62k), Laptev (-39k), Baffin (-17k) and ESS (-16k). 

Shadow NSIDC extent is now 10.9823  (-15.4k). Baffin did a big drop of -44k, and had some help from Laptev (-16k). Spoilers are CAB (+26k) and Barents (+16k).

The delta map is rather spectacular today.
Title: Re: 2016 sea ice area and extent data
Post by: andy_t_roo on June 04, 2016, 07:08:44 AM
Wipneus,
Is the F18 data available for last year?
if so you could get a feel for how accurate is by running last years data through your algorithm, and comparing the the F17 data previously used.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 04, 2016, 08:45:05 AM
Wipneus,
Is the F18 data available for last year?
if so you could get a feel for how accurate is by running last years data through your algorithm, and comparing the the F17 data previously used.

No. The only dates for which I have parallel measurements are from 1st of April to the beginning of May. During most of that time the F17 was broken. IIRC during 1-4 April the F17 was still OK, that data could be checked.
Title: Re: 2016 sea ice area and extent data
Post by: ktonine on June 04, 2016, 02:27:55 PM
Wipneus,
Is the F18 data available for last year?
No. The only dates for which I have parallel measurements are from 1st of April to the beginning of

You could ask Robert Grumbine over on his blog -- More Grumbine Science (http://moregrumbinescience.blogspot.com/) -- if it's available.  He has to work with the data as part of his day job.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 04, 2016, 04:16:50 PM
Shadow CT-area report (based on F18 NSIDC sea ice concentration data, we don't know if it is calibrated):

day  CT-date       NH               SH                Global
Fri 2016.4164  -32.1  9.322127 +187.9  9.198832  +155.8 18.520959
Sat 2016.4192  -22.0  9.300101 +160.8  9.359640  +138.8 18.659741
Sun 2016.4219 -156.5  9.143601 +100.7  9.460318   -55.8 18.603919
Mon 2016.4247  -97.3  9.046261 +199.7  9.660023  +102.4 18.706284

The near century show another big drop in the ESS (-46k), with Hudson (-19k),  CAA (-25k), Baffin and Kara (both -12k).

Shadow NSIDC extent 10.9997, up by  +17.4k. Very mixed results, Hudson, Greenland Sea, Barents and Bering went up. Okhotsk, Baffin and Kara lost extent.

The attached delta map shows the concentration drop in ESS, CAA and CAB, and increase in Laptev and (elsewhere) in the CAB.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on June 05, 2016, 04:25:07 PM
ADS-NIPR Extent:
10,354,257 km2 (04 June)
Down 3,588,250 km2 (25.74%) from 2016 maximum of 13,942,507 km2 on 29 February.
7,176,802 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Up 3,537 km2 (.03%) from previous day.
Down 223,174 km2  (-2.11%) over past seven days (daily average: -31,882 km2).
Down 72,787 km2  (-.59%) for June (daily average: -18,197 km2).
1,129,707 km2 below 2000s average for this date.
646,031 km2 below 2010s average for this date.
334,711 km2 below 2015 value for this date.
998,455 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 04 June) average.
Lowest June to-date average.
Lowest value for the date.
101 days this year (65.16% year-to-date) have recorded the lowest daily extent.
27 days (17.42%) have recorded the second lowest.
14 days (9.03%) have recorded the third lowest.
142 days in total (91.61%) have been among the lowest three on record.


CT Area:
9,046,261 km2 (05 June [Day 0.4247])
Down 3,875,097 km2 (29.99%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
6,812,252 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 97,340 km2 (-1.06%) from previous day.
Down 480,473 km2 (-5.06%) over past seven days (daily average: -68,639 km2).
Down 384,793 km2 (-3.45%) for June (daily average: -76,959 km2).
1,044,391 km2 below 2000s average for this date.
644,823 km2 below 2010s average for this date.
765,090 km2 below 2015 value for this date.
709,884 km2 below 2012 value for this date.
Lowest value for the date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' area numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!


Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 05, 2016, 04:40:13 PM
Shadow CT-area report (based on F18 NSIDC sea ice concentration data, we don't know if it is calibrated):

day  CT-date       NH               SH                Global
Sat 2016.4192  -22.0  9.300101 +160.8  9.359640  +138.8 18.659741
Sun 2016.4219 -156.5  9.143601 +100.7  9.460318   -55.8 18.603919
Mon 2016.4247  -97.3  9.046325 +199.8  9.660105  +102.5 18.706430
Tue 2016.4274  -71.5  8.974781  +51.3  9.711412   -20.2 18.686193

A rather large total extent drop, but the regional ones are huge! The ESS dropped now -78k while the CAB's restoration countered by +57k. Baffin, Beaufort and Lakes are much more modest, each about -11k.

Shadow NSIDC extent was 10.9802 ( -19.5k). Here Hudson (+25k) and Chukchi (+20k), went up, where Okhotsk (-17k) , Baffin (-16k ) and Barents (-13k)  came down in extent.

In the attached delta map there is still the patterns over Chukchi/ESS/Laptev and CAB. In the CAA the serious melt in the south can be seen (where in the north the concentration restored).
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on June 05, 2016, 05:14:09 PM
Shadow CT-area report (based on F18 NSIDC sea ice concentration data, we don't know if it is calibrated):

day  CT-date       NH               SH                Global
Sat 2016.4192  -22.0  9.300101 +160.8  9.359640  +138.8 18.659741
Sun 2016.4219 -156.5  9.143601 +100.7  9.460318   -55.8 18.603919
Mon 2016.4247  -97.3  9.046325 +199.8  9.660105  +102.5 18.706430
Tue 2016.4274  -71.5  8.974781  +51.3  9.711412   -20.2 18.686193

Thanks. That's now the earliest SIA has been below 9 million km2. But by just five days; I predict that 2016's area will drop (rise?) to second place behind 2012 within the next two weeks (say, June 20).
Title: Re: 2016 sea ice area and extent data
Post by: AmbiValent on June 05, 2016, 05:34:39 PM
After looking at the Reanalyzer forecast for the next week, I predict 2016 will still be clearly in the lead (400-600k).
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on June 05, 2016, 06:45:44 PM
Update for the week to June 4th

The current 5 day trailing average is on 11,011,000km2 while the 1 day extent is at 10,980,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,450,000km2, a decrease from -1,514,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -956,000km2, a decrease from -1,021,000km2 last week. We're currently the lowest on record, the same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FntVT8Zk.png&hash=c5fa24f7ab73e4e714218ddcf56c93a4)

The average daily change over the last 7 days was -46.7k/day, compared to the long term average of -55.8k/day, and the 07, 11 and 12 average of -56.0k/day.
The average long term change over the next week is -48.7k/day, with the 07, 11, and 12 average being -77.9k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FVSJwe4D.png&hash=73eb9410ff6edd7ff9b86dfb2694e14f)

The extent drop so far this June is the 5th smallest on record. To achieve the largest monthly loss, a drop of at least 104.8k/day is required (requiring ~112.2k/day with with single day values), while the smallest loss requires a drop less than 34.4k/day (<36.0k/day with single day values) and an average loss requires a increase of 57.6k/day (~53.1k/day with single day values).

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FaBXRyKt.png&hash=13169e21aea8da150d8f3f16ad8de387)

The extent loss in May was the 3rd largest on record, while the average extent was the lowest on record.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FdRfZnyA.png&hash=bd00be7ab3a2659cf66ca8a99bbb2ca4)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FW08Jn3G.png&hash=65056f2005cf9453b27883ffc989f891)
Title: Re: 2016 sea ice area and extent data
Post by: DavidR on June 06, 2016, 12:39:21 AM
Thanks. That's now the earliest SIA has been below 9 million km2. But by just five days; I predict that 2016's area will drop (rise?) to second place behind 2012 within the next two weeks (say, June 20).
The most likely date is June 16th, which is when the 2012 plummet finishes. After that 2012 flatlines for 4 days then drops at a pretty average rate for the rest of the month.

If 2016 has average drops for the rest of the month it will be very close to 2012 on June 16th. It will then  retake the lead for the rest of the month.  I  expect 2016 to drop faster than  average and retain its lead. So far this month area has dropped 108K per day, compared with an average of 79K and 2012s,  22K.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 06, 2016, 05:35:17 PM
Shadow CT-area report (based on F18 NSIDC sea ice concentration data, we don't know if it is calibrated):

day  CT-date       NH               SH                Global
Sun 2016.4219 -156.5  9.143601 +100.7  9.460318   -55.8 18.603919
Mon 2016.4247  -97.3  9.046325 +199.8  9.660105  +102.5 18.706430
Tue 2016.4274  -71.5  8.974842  +51.3  9.711446   -20.1 18.686288
Wed 2016.4301  -41.3  8.933579 +148.2  9.859658  +106.9 18.793237

Regionally the numbers diverge, CAB increased (+33), Hudson (-17k), Chukchi (-14k) and Laptev (-13k) lost area.

The shadow NSIDC extent is now at 10.9646 a droplet of  -15.6k. None of the regions did change much.

In the attached delta map many of the (sub-)regional changes can be seen.
Title: Re: 2016 sea ice area and extent data
Post by: lanevn on June 06, 2016, 07:03:46 PM

day  CT-date       NH               SH                Global
Sun 2016.4219 -156.5  9.143601 +100.7  9.460318   -55.8 18.603919
Mon 2016.4247  -97.3  9.046325 +199.8  9.660105  +102.5 18.706430
Tue 2016.4274  -71.5  8.974842  +51.3  9.711446   -20.1 18.686288
Wed 2016.4301  -41.3  8.933579 +148.2  9.859658  +106.9 18.793237


And where is current increase in area?
Title: Re: 2016 sea ice area and extent data
Post by: anotheramethyst on June 06, 2016, 07:12:36 PM

day  CT-date       NH               SH                Global
Sun 2016.4219 -156.5  9.143601 +100.7  9.460318   -55.8 18.603919
Mon 2016.4247  -97.3  9.046325 +199.8  9.660105  +102.5 18.706430
Tue 2016.4274  -71.5  8.974842  +51.3  9.711446   -20.1 18.686288
Wed 2016.4301  -41.3  8.933579 +148.2  9.859658  +106.9 18.793237


And where is current increase in area?

You're probably thinking of the increase in extent.  You can check the IJIS thread for more detail on that. 

Edit-sorry I didn't see the increase in area mentioned before.  I read the threads in the wrong order, apparently :( 
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on June 06, 2016, 07:45:40 PM

day  CT-date       NH               SH                Global
Sun 2016.4219 -156.5  9.143601 +100.7  9.460318   -55.8 18.603919
Mon 2016.4247  -97.3  9.046325 +199.8  9.660105  +102.5 18.706430
Tue 2016.4274  -71.5  8.974842  +51.3  9.711446   -20.1 18.686288
Wed 2016.4301  -41.3  8.933579 +148.2  9.859658  +106.9 18.793237


And where is current increase in area?

You're probably thinking of the increase in extent.  You can check the IJIS thread for more detail on that.

the question is legit after reading the below linked post from this morning where he stated that extend & area
increased. thought the same but was sure it will be explained eventually :-) let's see

http://forum.arctic-sea-ice.net/index.php/topic,382.msg79320.html#msg79320 (http://forum.arctic-sea-ice.net/index.php/topic,382.msg79320.html#msg79320)
Title: Re: 2016 sea ice area and extent data
Post by: AmbiValent on June 06, 2016, 07:50:47 PM
That's data from a different satellite.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Hunt on June 06, 2016, 07:52:27 PM
the question is legit after reading the below linked post from this morning where he stated that extend & area
increased. thought the same but was sure it will be explained eventually :-) let's see

That's based on the "Homebrew" AMSR2 based numbers. In this thread Wipneus publishes his DMSP F-18 SSMIS based "Shadow CT" numbers
Title: Re: 2016 sea ice area and extent data
Post by: seaicesailor on June 06, 2016, 07:54:41 PM
Quote from: magnamentis
the question is legit after reading the below linked post from this morning where he stated that extend & area
increased. thought the same but was sure it will be explained eventually :-) let's see

http://forum.arctic-sea-ice.net/index.php/topic,382.msg79320.html#msg79320 (http://forum.arctic-sea-ice.net/index.php/topic,382.msg79320.html#msg79320)

These are different measurements of area and extent (NSIDC vs AMSR2 uni hamburg data), different satellites and instrumentation. Wipneus has the attention of sharing his calculations over both datasets.
AMSR2 area is less affected by surface melting, hence it does not depart from AMSR2 extent as much. That much I know :-|
Title: Re: 2016 sea ice area and extent data
Post by: Sebastian on June 06, 2016, 11:26:29 PM
Above 2012 by the end of the week/beginning of next week? Jun 8th 2016 is at 8.93m. June 15th 2012 was at ca. 8.0m

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fneven1.typepad.com%2F.a%2F6a0133f03a1e37970b01bb08461733970d-pi&hash=543fc80ff83bcdb053e381e55bb05492)

( Image from Neven's blog from last year http://neven1.typepad.com/blog/2015/06/asi-2015-update-3-whats-it-going-to-be.html (http://neven1.typepad.com/blog/2015/06/asi-2015-update-3-whats-it-going-to-be.html) )
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on June 07, 2016, 12:53:15 PM
ADS-NIPR Extent:
10,333,107 km2 (06 June)
Down 3,609,400 km2 (25.89%) from 2016 maximum of 13,942,507 km2 on 29 February.
7,155,652 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 20,208 km2 (-.2%) from previous day.
Down 147,583 km2  (-1.41%) over past seven days (daily average: -21,083 km2).
Down 93,937 km2  (-.77%) for June (daily average: -15,656 km2).
1,057,538 km2 below 2000s average for this date.
544,120 km2 below 2010s average for this date.
256,229 km2 below 2015 value for this date.
838,662 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 06 June) average.
Lowest June to-date average.
Lowest value for the date.
103 days this year (65.61% year-to-date) have recorded the lowest daily extent.
27 days (17.2%) have recorded the second lowest.
14 days (8.92%) have recorded the third lowest.
144 days in total (91.72%) have been among the lowest three on record.


CT Area:
8,933,579 km2 (07 June [Day 0.4302])
Down 3,987,779 km2 (30.86%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
6,699,570 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 41,263 km2 (-.46%) from previous day.
Down 497,475 km2 (-5.32%) over past seven days (daily average: -71,068 km2).
Down 497,475 km2 (-4.47%) for June (daily average: -71,068 km2).
1,048,994 km2 below 2000s average for this date.
617,765 km2 below 2010s average for this date.
666,829 km2 below 2015 value for this date.
728,143 km2 below 2012 value for this date.
Lowest value for the date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' area numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!


Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 07, 2016, 04:29:34 PM
Shadow CT-area report (based on F18 NSIDC sea ice concentration data, we don't know if it is calibrated):

day  CT-date       NH               SH                Global
Mon 2016.4247  -97.3  9.046325 +199.8  9.660105  +102.5 18.706430
Tue 2016.4274  -71.5  8.974842  +51.3  9.711446   -20.1 18.686288
Wed 2016.4301  -41.0  8.933828 +148.2  9.859680  +107.2 18.793508
Thu 2016.4329  -44.6  8.889271  +41.4  9.901063    -3.2 18.790334


That would have been a drop of -62.6k if not for "lake ice" which increased by 18.1k. The regions that dropped big are CAA (-26k), Huson (-18k) and Baffin (-14k). On the other side of the Arctic Kara dropped -16k, but the ESS increases 15k.

Shadow NSIDC extent is now 10.9192  dropping -45.5k. Baffin is the big guy here, -32k, followed by Greenland Sea (-16k) and Hudson (-13k).

The attached delta map shows the focus of the changes over the CAA and a new front over the southern Hudson.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 08, 2016, 04:53:06 PM
Shadow CT-area report (based on F18 NSIDC sea ice concentration data, we don't know if it is calibrated):

day  CT-date       NH               SH                Global
Tue 2016.4274  -71.5  8.974842  +51.3  9.711446   -20.1 18.686288
Wed 2016.4301  -41.0  8.933828 +148.2  9.859680  +107.2 18.793508
Thu 2016.4329  -44.4  8.889441  +41.4  9.901071    -3.0 18.790512
Fri 2016.4356  -57.6  8.831831 +104.5 10.005570   +46.9 18.837401

Big disagreements between the regions. ESS increased by 41k, while Caa dropped -32k, CAB -30k, Hudson -21k and Laptev -18k.
Shadow NSIDC is now 10.8651  (-54.1k). Drops are outside the Arctic Basin: Okhotsk (-24k), Hudson (-16k) and Greenland Sea (-14k).

The attached delta map has all the details.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 09, 2016, 04:50:29 PM
Extent and area may drift apart as today's NSIDC sea ice concentration shows.

First the shadow CT-area report notes a fat century :

day  CT-date       NH               SH                Global
Wed 2016.4301  -41.0  8.933828 +148.2  9.859680  +107.2 18.793508
Thu 2016.4329  -44.4  8.889441  +41.4  9.901071    -3.0 18.790512
Fri 2016.4356  -57.2  8.832199 +104.5 10.005600   +47.3 18.837799
Sat 2016.4384 -136.5  8.695739 +147.8 10.153355   +11.3 18.849094

Laptev is here the biggest looser (of area): -49k. Hudson and Baffin each lost -27k, CAB was -21k and the ESS -17k.

The shadow NSIDC came out at 10.8701  a small increase +5.0k. Cause is the Barents Sea extent increase of +26k and only small changes in the other regions.

The attache delta map shows the wide spread concentration drops. All melting in action, waiting for the sun.



Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 10, 2016, 06:00:19 PM
Also with the data derived from NSIDC gridded sea ice concentration we see a big drop in area and a much smaller drop in extent.

Shadow CT-area report (based on F18 NSIDC sea ice concentration data, we don't know if it is calibrated):

day  CT-date       NH               SH                Global
Thu 2016.4329  -44.4  8.889441  +41.4  9.901071    -3.0 18.790512
Fri 2016.4356  -57.2  8.832199 +104.5 10.005600   +47.3 18.837799
Sat 2016.4384 -136.4  8.695805 +147.8 10.153372   +11.4 18.849177
Sun 2016.4411 -145.8  8.549955 +168.8 10.322178   +23.0 18.872133

Many regions contribute, Kara (-32k), Cab (-29k), Hudson (-24k) and ESS (-22k) are the biggest.

Shadow NSIDC extent is 10.8434  (-26.7k). Kara did a larger drop (-42k), but extent in Baffin increased (+13k).

In the attached delta map, notice the dark colors in the Canadian Archipelago on the one side and in ESS/Laptev on the  other side.
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on June 10, 2016, 08:33:27 PM
Those area plunges are simply enormous especially considering they now make up ~ -1.5% of the remaining pack (each day!).

With temps 80N+ at 0+ the earliest on record per DMI, this should come as no surprise; the stall in extent drops is now manifesting in the area plunge, which should continue for the forseeable future as the CAB ice continues to be yoinked into the Greenland Sea while the main pack is now splitting in two.
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on June 10, 2016, 09:33:19 PM
With temps 80N+ at 0+ the earliest on record per DMI

a very important and accurate observation, many mentioned the "extraordinary heat in 2012, which, looking at the charts more thoroughl, was not that extraordinary and we're now above zero average the earliest indeed and, at least as important, the daily lows around the pole, according to Climate Reanalizer, will stay above zero day and "night" (hours) i know there is not "night" of course, but i think it's clear what i mean.
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on June 10, 2016, 09:50:13 PM

Shadow NSIDC extent is 10.8434  (-26.7k). Kara did a larger drop (-42k), but extent in Baffin increased (+13k).

In the attached delta map, notice the dark colors in the Canadian Archipelago on the one side and in ESS/Laptev on the  other side.

The Baffin increase without a doubt is dispersion.  Looking at Worldview there's some large stretches of very "filmy" ice.

I'm expecting ESS and Laptev ice to start coming apart in earnest in about a week.  By then I think the 40-50CM (or more...) of combined top and bottom melt that will have gone on there since the start of the "torch" will have weakened the ice sufficiently it will no longer be able to stand up intact to wind and tide.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 11, 2016, 05:34:37 PM
As reported earlier the conditions for ice surface melting (with associated melt ponds) have taken a sudden stall. The NSIDC sea ice concentration data speaks event more loudly.

Shadow CT-area report (based on F18 NSIDC sea ice concentration data, we don't know if it is calibrated):

day  CT-date       NH               SH                Global
Fri 2016.4356  -57.2  8.832199 +104.5 10.005600   +47.3 18.837799
Sat 2016.4384 -136.4  8.695805 +147.8 10.153372   +11.4 18.849177
Sun 2016.4411 -146.0  8.549799 +168.8 10.322178   +22.8 18.871977
Mon 2016.4438 +100.3  8.650100 +114.6 10.436785  +214.9 19.086885

That is a century increase, almost all caused by the CAB: +87k with Laptev adding +20k to the total. Other regions had only small changes.

Shadow NSIDC extent came out at 10.782.3  (-61.1k). Here Baffin is the single region (-46k), all other regions had much smaller changes.

The attached delta-map shows the increase in concentration in the center of the CAB and a broad swath along the Canadian islands and the north of Greenland.
 
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on June 11, 2016, 06:03:58 PM
And just like that, 2016's massive lead over 2012 (which has averaged a whopping 740k since mid-February) has vanished; there's now but a mere 35k of area separating the two years, and with 2012 having dropped nearly 900k over the next six days--and given the current Arctic forecast--expect 2016 to fall behind by up to half a million square kilometers or so in the next week.

FWIW, yesterday's century increase is the largest June one-day rise since 2011, and only the fourth ever in the satellite record.
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on June 11, 2016, 09:04:03 PM

FWIW, yesterday's century increase is the largest June one-day rise since 2011, and only the fourth ever in the satellite record.
... and amazingly weird.  The best explanation I have is draining melt ponds.
Title: Re: 2016 sea ice area and extent data
Post by: oren on June 11, 2016, 09:06:26 PM

FWIW, yesterday's century increase is the largest June one-day rise since 2011, and only the fourth ever in the satellite record.
... and amazingly weird.  The best explanation I have is draining melt ponds.

Or melt pond refreeze in the CAB?
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on June 11, 2016, 09:07:35 PM

FWIW, yesterday's century increase is the largest June one-day rise since 2011, and only the fourth ever in the satellite record.
... and amazingly weird.  The best explanation I have is draining melt ponds.

Or melt pond refreeze in the CAB?

Not sure it's cold enough, with all of the insolation, even through clouds.
Title: Re: 2016 sea ice area and extent data
Post by: slow wing on June 12, 2016, 01:09:50 AM
Yep, it has to be a refreeze. The melt ponds over a broad swathe aren't all going to choose to drain on the same day.

+100K! That's a big uptick!
Title: Re: 2016 sea ice area and extent data
Post by: JKDMaineUSA on June 12, 2016, 03:07:53 AM
Probably just part of the calibration process that is on going ..
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on June 12, 2016, 03:21:01 AM
glad you mention it, none of the visuals confirms that an Uni Bremen does not show that, hence i'd take it with a prise of salt. temps are a bit high for a large scale refreeze IMO, let's see, but i expect some kind of correction.
Title: Re: 2016 sea ice area and extent data
Post by: oren on June 12, 2016, 11:06:39 AM
It could also be wet snow refreezing. I don't know much about the algorithms involved but I seem to remember water on the surface is what decides ice or no ice for the area calculation.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 12, 2016, 04:59:28 PM
It is unpreventable, in June the numbers will go down again even after a century increase.

Here is the shadow CT-area report (based on F18 NSIDC sea ice concentration data, we don't know if it is calibrated):

day  CT-date       NH               SH                Global
Sat 2016.4384 -136.4  8.695805 +147.8 10.153372   +11.4 18.849177
Sun 2016.4411 -146.0  8.549799 +168.8 10.322178   +22.8 18.871977
Mon 2016.4438 +100.3  8.650090 +114.7 10.436848  +215.0 19.086938
Tue 2016.4466  -81.6  8.568522 +187.5 10.624377  +106.0 19.192899

The CAB is still not cooperating (+35k), also ESS is in recovery (+15k). In other regions the summer melting is causing declines, CAA (-33k), Baffin (-25k), Kara (-22k) and Laptev (-21k) are the biggest.

Shadow NSIDC extent is down to 10.6983  (-83.9k). Baffin takes half (-40k), the remains are split up by Kara, Greenland Sea, Barents and Hudson (-22k, -18k, -15k and -14k).

The attached delta map shows an active Arctic with melting and recovery in many places.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on June 12, 2016, 05:00:41 PM
Update for the week to June 11th

The current 5 day trailing average is on 10,812,000km2 while the 1 day extent is at 10,698,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,309,000km2, a decrease from -1,450,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -610,000km2, a decrease from -956,000km2 last week. We're currently the lowest on record, the same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FHmUqZys.png&hash=d9fdc020a2bc1f44e2e92a789ce0ad97)

The average daily change over the last 7 days was -28.5k/day, compared to the long term average of -48.7k/day, and the 07, 11 and 12 average of -77.9k/day.
The average long term change over the next week is -48.0k/day, with the 07, 11, and 12 average being -82.1k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FUzozcb6.png&hash=0143a3c5e173473cfb096053152129e0)

The extent drop so far this June is the 2nd smallest on record. To achieve the largest monthly loss, a drop of at least 132.9k/day is required (requiring ~141.8k/day with with single day values), while the smallest loss requires a drop less than 36.6k/day (<34.2k/day with single day values) and an average loss requires a drop of 68.3k/day (~69.7k/day with single day values).

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F9eqw7Js.png&hash=aaa63c96be068d9d71a1c58c95a7d4e3)
Title: Re: 2016 sea ice area and extent data
Post by: Steven on June 12, 2016, 05:16:42 PM
Here is the shadow CT-area report (based on F18 NSIDC sea ice concentration data, we don't know if it is calibrated):

day  CT-date       NH                             
Sat 2016.4384 -136.4  8.695805
Sun 2016.4411 -146.0  8.549799
Mon 2016.4438 +100.3  8.650090
Tue 2016.4466  -81.6  8.568522


Thanks for these data.  Comparing your calculated shadow CT-area values for the last few weeks (red dashed line) with the corresponding CT-area values for previous years, 2016 is now virtually tied with 2012  (assuming there are no calibration issues):


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FaI0Zj1y.png&hash=74aadf173135e3a58ce4bedb6a20de7e)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on June 12, 2016, 06:31:06 PM
This marks the first time in 103 days--since 12 February--that 2016 SIA has been above 2012. It's also the first time in 55 days that 2016 SIA has been in any position besides first. Among other factoids: even if 2016 were to precisely follow 2012's daily trajectory from now until mid-September--complete with the remainder of that year's steep June cliff and the GAC, etc.--it still wouldn't set a record.
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on June 12, 2016, 06:45:35 PM
This marks the first time in 103 days--since 12 February--that 2016 SIA has been above 2012. It's also the first time in 55 days that 2016 SIA has been in any position besides first. Among other factoids: even if 2016 were to precisely follow 2012's daily trajectory from now until mid-September--complete with the remainder of that year's steep June cliff and the GAC, etc.--it still wouldn't set a record.
How is it a factoid that a year behind another year wouldn't beat that year if it had the same drop as that year? That is common sense.

I think the rhetoric re: optimism is LOLworthy and both models and satellite show massive heat into the Arctic through D10. IMO, the false area drops and rises are a sign that the main pack is now being pre-conditioned. Meanwhile, the peripheral seas are about to start falling apart.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on June 12, 2016, 06:51:52 PM
How is it a factoid that a year behind another year wouldn't beat that year if it had the same drop as that year? That is common sense.

Not sure I follow you. A "factoid" is a trivial bit of information. Do you use an alternate definition of the term?

I think the rhetoric re: optimism is LOLworthy and both models and satellite show massive heat into the Arctic through D10. IMO, the false area drops and rises are a sign that the main pack is now being pre-conditioned. Meanwhile, the peripheral seas are about to start falling apart.

You're missing the point. I'm merely stating facts and figures. For me to say that following 2012's daily behavior from here on would not result in beating that year's record minimum is neither "rhetoric" nor "optimism"; it's just telling it like it is. As to whether it's "LOLworthy" I'll leave up to the individual; I guess some people are just more easily amused.  ;)
Title: Re: 2016 sea ice area and extent data
Post by: Nick_Naylor on June 12, 2016, 07:33:21 PM
It IS almost too obvious that - anytime you're not already at record levels - following the subsequent trajectory of the record year won't lead to a new record.
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on June 12, 2016, 08:31:01 PM
How is it a factoid that a year behind another year wouldn't beat that year if it had the same drop as that year? That is common sense.

Not sure I follow you. A "factoid" is a trivial bit of information. Do you use an alternate definition of the term?

I think the rhetoric re: optimism is LOLworthy and both models and satellite show massive heat into the Arctic through D10. IMO, the false area drops and rises are a sign that the main pack is now being pre-conditioned. Meanwhile, the peripheral seas are about to start falling apart.

You're missing the point. I'm merely stating facts and figures. For me to say that following 2012's daily behavior from here on would not result in beating that year's record minimum is neither "rhetoric" nor "optimism"; it's just telling it like it is. As to whether it's "LOLworthy" I'll leave up to the individual; I guess some people are just more easily amused.  ;)
You are not stating a helpful fact, it is like saying if you start at 2 you can count quicker to 10 than if you start at 1 -- duh... not insightful whatsoever and does not further discourse, esp. when, IMO, you seem to be minimizing the impacts of the melt this yr.
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on June 12, 2016, 08:37:43 PM
...back to sea ice, we are starting to see firmer evidence that the entire Arctic ice mass is now cleaving in two, which would be unprecedented.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Focean.dmi.dk%2Fanim%2Fplots%2Ficec.arc.121.png&hash=2263e5e6456542637aeb7a2a41ed714d)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Farcticicen%2Fnowcast%2Ficen2016061118_2016061900_042_arcticicen.001.gif&hash=f769a3cc19fb68f6bc615e8e37eb58eb)

It seems that the losses directly adjacent to the Russian side keep filtering SE/SW as the ice gets pushed and pulled. Meanwhile, the reversal in the Beaufort Gyre is now pushing open water directly towards the same area (although even when it runs normally, you still have weakness pushing into the same area from the other direction).

Meanwhile, the crazy FRAM export has allowed large fissures to develop in the departing wake of the main CAB ice.

This did not happen in 2012!
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on June 12, 2016, 08:42:04 PM
sometimes it's important to consider the exact order of the events. the statement you criticize was the REPLY after someone questioned a post that simply stated obvious facts, like a color blind questioning that i see green and then when i say; but you're color blind, someone else would say, but that's not nice [shake head]

it's certainly never wrong to state the obvious and it's certainly legit to get a bit annoyed if people who don't think before they write are starting to question the obvious in a, to a certain degree, condescending manner.

and then if someone is known to provide perfect and valuable information for all of us it's perhaps one more good reason to read and consider very carefully before shooting away. at least my generation was raised to way to show a bit of extra respect towards the elderly (more experienced) members of a society.

over and out
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on June 12, 2016, 08:53:49 PM
sometimes it's important to consider the exact order of the events. the statement you criticize was the REPLY after someone questioned a post that simply stated obvious facts, like a color blind questioning that i see green and then when i say; but you're color blind, someone else would say, but that's not nice [shake head]

it's certainly never wrong to state the obvious and it's certainly legit to get a bit annoyed if people who don't think before they write are starting to question the obvious in a, to a certain degree, condescending manner.

and then if someone is known to provide perfect and valuable information for all of us it's perhaps one more good reason to read and consider very carefully before shooting away. at least my generation was raised to way to show a bit of extra respect towards the elderly (more experienced) members of a society.

over and out
The elderly have destroyed this planet with no regard for young people. Baby boomers may single handedly rank amongst the devastating events this planet has ever experienced. So I don't think that automatically kow-towing to someone bc they are older and probably uninformed is sensible, but that is just me.

You can compare the change in HYCOM over the past two weeks. The pack is clearly breaking up entirely.

Maybe if Baby Boomers hadn't been so blindly selfish we wouldn't be witnessing what's about to unfold. No matter, but most definite proof that age does not automatically merit respect.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Farcticicen%2Fnowcast%2Ficen2016061118_2016061200_042_arcticicen.001.gif&hash=9db904632f9005678b8d5cafbb0aaba7)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Farcticicen%2Fnowcast%2Ficen2016052818_2016052900_042_arcticicen.001.gif&hash=00f4b07395b349cd2ebc0e4173e71932)
Title: Re: 2016 sea ice area and extent data
Post by: seaicesailor on June 12, 2016, 09:27:28 PM
The elderly have destroyed this planet with no regard for young people. Baby boomers may single handedly rank amongst the devastating events this planet has ever experienced. So I don't think that automatically kow-towing to someone bc they are older and probably uninformed is sensible, but that is just me.
...
Maybe if Baby Boomers hadn't been so blindly selfish we wouldn't be witnessing what's about to unfold. No matter, but most definite proof that age does not automatically merit respect.

After saying that posts based on feelings should be banned you go and vomit this out... why don't you ban yourself?
over and out
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on June 12, 2016, 09:35:43 PM
The elderly have destroyed this planet with no regard for young people. Baby boomers may single handedly rank amongst the devastating events this planet has ever experienced. So I don't think that automatically kow-towing to someone bc they are older and probably uninformed is sensible, but that is just me.
...
Maybe if Baby Boomers hadn't been so blindly selfish we wouldn't be witnessing what's about to unfold. No matter, but most definite proof that age does not automatically merit respect.

After saying that posts based on feelings should be banned you go and vomit this out... why don't you ban yourself?
over and out
That is not a feeling it is a fact
Title: Re: 2016 sea ice area and extent data
Post by: Neven on June 12, 2016, 09:52:09 PM
That is not a feeling it is a fact

Nope, it is a feeling/opinion. And if it were a fact, it would lack nuance and context.

Could you turn the anger and alarmism a notch down, please? The entire Arctic ice mass is not going to cleave in two.
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on June 12, 2016, 10:37:55 PM
The elderly have destroyed this planet with no regard for young people.

but you remember who we were talking about, about "jim" so this is not only inappropriate but out of context as well. as far as i know there is perfect thread where i will gladly hold the mirror.

http://forum.arctic-sea-ice.net/index.php/topic,1548.msg79951.html#msg79951 (http://forum.arctic-sea-ice.net/index.php/topic,1548.msg79951.html#msg79951)
Title: Re: 2016 sea ice area and extent data
Post by: DavidR on June 13, 2016, 04:38:01 AM
This marks the first time in 103 days--since 12 February--that 2016 SIA has been above 2012....  if 2016 were to precisely follow 2012's daily trajectory from now until mid-September--complete with the remainder of that year's steep June cliff...
(Averages below are based on the past 10 years)
It  is worth noting that the 2012 decline from now to the end of the month is only slightly above average compared to the last 10 years. Three years had greater declines in area and four years had greater declines in extent. For July, 2012 was only 60K km^2 above average in both measures and beaten by 2015, and others.

Although it will be hard for 2016 to  keep pace with 2012 for area over the next 5 days, an average decline over the next 8 will see 2016 ahead again. 

Both IJIS and NSIDC extent are well below 2012 levels and will probably not be caught for some time.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on June 13, 2016, 01:03:47 PM
Although it will be hard for 2016 to  keep pace with 2012 for area over the next 5 days, an average decline over the next 8 will see 2016 ahead again.

Over the next 21 days, 2012 area dropped by 2.34 Million km2, a sustained average of 111k per day. So while it's very possible that 2016 will retake first and hold it for awhile, I've not seen anything in the forecast to suggest that will happen. The average June-to-date daily drop has so far been a sluggish 66k; what's going to push a near doubling of that?

Both IJIS and NSIDC extent are well below 2012 levels and will probably not be caught for some time.

I suppose it depends on how one defines "well below", but thanks to closing the 2016-2012 gap by 627k over the past six days, the latter is now breathing strongly down the neck of the former where IJIS extent is concerned. And with 2012 having fallen an additional 177k over the next two days, while 2016 has averaged a daily drop of just 25k so far this month, I suspect the difference will practically vanish over the next five days or so.  Of course, as you've noted, after that 2012's trajectory became more normal for several week; that year didn't move into and hold first place until the end of July, so there's still a great chance that will happen.

(I know a few people haven't been pleased with some of the figures I've been posting, but I'm simply stating facts. And the fact is, 2016's enormous lead over 2012--higher than a million square kilometers at some points--has for all intents and purposes gone away over the past ten days. That doesn't mean it's permanent. But it is what's happening.)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 13, 2016, 04:31:57 PM
The spirit seems to be out of the melting, judging by the total Arctic numbers.

Here is the shadow CT-area report (based on F18 NSIDC sea ice concentration data, we don't know if it is calibrated):

day  CT-date       NH               SH                Global
Sun 2016.4411 -146.0  8.549799 +168.8 10.322178   +22.8 18.871977
Mon 2016.4438 +100.3  8.650090 +114.7 10.436848  +215.0 19.086938
Tue 2016.4466  -81.5  8.568613 +187.6 10.624465  +106.1 19.193078
Wed 2016.4493   +7.7  8.576314 +104.0 10.728515  +111.8 19.304829

That is mostly caused by the CAA (+28k). The decline in Chukchi (-19k) is not enough.

Shadow NSIDC extent is 10.7191 an increase of +20.8k. Here is no particular region responsible, Kara declined -18k and many others had little plus'es.

The attached deltamap shows something similar as the melting graphs in the "home brew" thread: melting shifts from ESS to Chukchi and Beaufort.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 14, 2016, 04:27:44 PM
Declining moderate rates for this time of year.

Here is the shadow CT-area report (based on F18 NSIDC sea ice concentration data, we don't know if it is calibrated):

day  CT-date       NH               SH                Global
Mon 2016.4438 +100.3  8.650090 +168.8 10.322178  +269.1 18.972268
Tue 2016.4466  -81.5  8.568613 +114.7 10.436848   +33.2 19.005461
Wed 2016.4493   +7.8  8.576390 +187.6 10.624465  +195.4 19.200855
Thu 2016.4521  -57.0  8.519380 +104.0 10.728515   +47.0 19.247895

The area decline is inflated by a big drop in "lake ice" (probably false, in any case not relevant) which dropped -24k. Recoveries by ESS (+25k), Laptev (+20k) and CAB (+13k). Declines in CAA (-33k), Hudson (-20k) and Greenland Sea (-20k).

NSIDC extent is now 10.6571 dropping  -62.6k. Hudson and Kara lost each about -20k.

The attached delta map shows another way where the day-to-day changes were.
Title: Re: 2016 sea ice area and extent data
Post by: Steven on June 14, 2016, 04:38:17 PM
Thu 2016.4521  ...  8.519380

(Assuming it is calibrated:)  This is about 315k km2 above the 2012 value for this date, and about 225 to 335 k km2 below the 2007/2010/2011 values for this date:


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fy8Q196M.png&hash=facb57241dc0b046d89e6a6b2856d808)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on June 15, 2016, 02:02:20 PM
ADS-NIPR Extent:
10,054,193 km2 (14 June)
Down 3,888,314 km2 (27.89%) from 2016 maximum of 13,942,507 km2 on 29 February.
6,876,738 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 46,444 km2 (-.46%) from previous day.
Down 243,619 km2  (-2.37%) over past seven days (daily average: -34,803 km2).
Down 372,851 km2  (-3.05%) for June (daily average: -26,632 km2).
963,085 km2 below 2000s average for this date.
329,237 km2 below 2010s average for this date.
283,058 km2 below 2015 value for this date.
110,925 km2 below 2012 value for this date.
1st lowest year-to-date (01 January - 14 June) average.
1st lowest June to-date average.
1st lowest value for the date.
111 days this year (67.27% year-to-date) have recorded the lowest daily extent.
27 days (16.36%) have recorded the second lowest.
14 days (8.48%) have recorded the third lowest.
152 days in total (92.12%) have been among the lowest three on record.


CT Area:
8,519,380 km2 (15 June [Day 0.452])
Down 4,401,978 km2 (34.07%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
6,285,371 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 57,010 km2 (-.66%) from previous day.
Down 370,061 km2 (-4.19%) over past seven days (daily average: -52,866 km2).
Down 911,674 km2 (-8.19%) for June (daily average: -60,778 km2).
905,640 km2 below 2000s average for this date.
280,799 km2 below 2010s average for this date.
467,061 km2 below 2015 value for this date.
315,435 km2 above 2012 value for this date.
2nd lowest value for the date.
At least 138* days in total have been among the lowest three on record.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' area numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!





Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 15, 2016, 04:49:20 PM
NSIDC has decided the F18 data are calibrated now (https://nsidc.org/the-drift/data-update/sea-ice-index-processing-resumed-with-dmsp-f18-satellite-data/):

Quote
After investigating the difference in ice extent as the algorithm tie points were varied, it was found that the current F17 tie points provided the best match in sea ice extent for the overlap period, so no adjustment in algorithm parameters was needed for F18.

I continue with the shadow numbers because CT has not picked the data up yet and adding the NSIDC extent data seems natural.

Here is the shadow CT-area report (based on F18 NSIDC sea ice concentration data that we now know are calibrated):

day  CT-date       NH               SH                Global
Tue 2016.4466  -81.5  8.568613 +114.7 10.436848   +33.2 19.005461
Wed 2016.4493   +7.8  8.576390 +187.6 10.624465  +195.4 19.200855
Thu 2016.4521  -57.1  8.519276 +104.3 10.728776   +47.2 19.248052
Fri 2016.4548 -108.1  8.411184  +52.5 10.781235   -55.6 19.192419

Century drop, with Hudson, CAA, Greenland Sea and CAB big contributors (-36k, -30k, -29k, -20k),
NSIDC ended at 10.5735 down -83.6k. Baffin championed het (-31k).

The attached delta map shows it all.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 16, 2016, 05:35:14 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

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

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

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

The attached delta map shows it all.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 17, 2016, 05:14:55 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

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

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

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

The attached delta map shows it all, in particular the decline of the ice around Svalbard.
Title: Re: 2016 sea ice area and extent data
Post by: Steven on June 17, 2016, 05:24:06 PM
Sun 2016.4603  ...  8.234949

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

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FrUzpV1p.png&hash=3b485855133f4ef70e2a879654cd737f)
Title: Re: 2016 sea ice area and extent data
Post by: oren on June 17, 2016, 05:43:41 PM
The attached delta map shows it all, in particular the decline of the ice around Svalbard.

The ice-killing zone strikes back.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on June 17, 2016, 05:49:10 PM
Even with that large extent drop, 2012 had dropped below 2016 with the daily values, knocking this year off lowest on record for the first time since April 17th
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on June 18, 2016, 09:57:22 AM
Hi Wipneus,
Since NSIDC does not publish daily "area" numbers, I'm trying to find a good analog.
Your "area" graph here seems a good start :
https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-area-all-cmpare.png

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

So I guess I'm confused. Could you publish NSIDC's past and 2016 "area" numbers in a graph or (even better) in a table ?
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 18, 2016, 12:07:08 PM
Rob,

My area numbers are in the same place as extent:

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

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

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

There is of course a whole lot of other data in that folder, like the 1981-2010 normals, Antarctic data and more.
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on June 20, 2016, 03:22:41 AM
Thanks Wipneus, and for the tremendous work you are doing. Especially this season, your work enabled many of us to stay focused on the data, which would not have been there without you.

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

Now I just need to calibrate your 'area' numbers to the ones that NSIDC publishes once a month, and find a daily stream for snow cover, and I could turn my monthly SIPN projection model for September into a daily one.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 20, 2016, 06:27:33 PM
The NSIDC F18 gridded sea ice concentration data stream that was stopped for a few days has resumed. Let us see.

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

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

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

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

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

Title: Re: 2016 sea ice area and extent data
Post by: Lord M Vader on June 20, 2016, 06:46:16 PM
Great job Wipneus! :) You, Espen, Neven, ASLR and many others are doing a tremendeous job.

How has the compactness rate evolved so far? Last I saw was a rather low value of compactness. Interesting to see whether extent numbers will go down by a century break as Hudson Bay (as well as Kara Sea) is "feeling the burn".
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on June 21, 2016, 02:23:39 PM
ADS-NIPR Extent:
9,636,570 km2 (20 June)
Down 4,305,937 km2 (30.88%) from 2016 maximum of 13,942,507 km2 on 29 February.
6,459,115 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 94,616 km2 (-.97%) from previous day.
Down 464,067 km2  (-4.59%) over past seven days (daily average: -66,295 km2).
Down 790,474 km2  (-6.46%) for June (daily average: -39,524 km2).
994,222 km2 below 2000s average for this date.
358,238 km2 below 2010s average for this date.
450,395 km2 below 2015 value for this date.
169,199 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 20 June) average.
Lowest June to-date average.
Lowest value for the date.
117 days this year (68.42% year-to-date) have recorded the lowest daily extent.
27 days (15.79%) have recorded the second lowest.
14 days (8.19%) have recorded the third lowest.
158 days in total (92.4%) have been among the lowest three on record.


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

Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 21, 2016, 04:42:09 PM
Double century extent drop!

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

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

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

The delta image shows in bright red colors where extent went down. Some of it is coastal ice like in Okhotsk but in other places (Kara, Hudson) the decline looks genuine.
Title: Re: 2016 sea ice area and extent data
Post by: Steven on June 21, 2016, 05:15:46 PM
here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

Thu 2016.4712  ...  7.829501

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


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FkKdqK12.png&hash=394f66675eb80a4ac6d86e6ab8f95ba5)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on June 21, 2016, 07:54:47 PM
Update for the week to June 18th

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

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

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FOAXBPXt.png&hash=84af983faaed9b57dbb56043e121df82)

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

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FdUBhJ85.png&hash=05705e3b28fe8049b0a1fa95a47a54ba)

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

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FpvBL19g.png&hash=4d716b01fc5f4623ddcd81c12b6e1620)
Title: Re: 2016 sea ice area and extent data
Post by: DavidR on June 21, 2016, 11:20:39 PM
NSIDC reports a 210 K extent drop for the 20th with the figure for the 19th  revised downward.
2016   6   19   10.239
2016   6   20   10.029

That makes a drop of almost 550K in the past 5 days and puts extent over 100K in front  again.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 22, 2016, 04:22:05 PM
The effects of the arctic low are visible in the concentration numbers.

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

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

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

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

The delta map should tell you the rest.
Title: Re: 2016 sea ice area and extent data
Post by: Shared Humanity on June 22, 2016, 07:33:45 PM
Looking at the concentration image, what I find amazing is how a relatively weak cyclone can wreak such havoc in the central CAB in such a short space of time. It really does support how the ice is no longer the ice of a decade ago. It is very mobile and very broken up.
Title: Re: 2016 sea ice area and extent data
Post by: slow wing on June 23, 2016, 12:39:50 AM
Some/most/all of that crimson in the Laptev Sea and CAB could be rain fallen on the ice where the storm went?

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

Note there is no change in the Chukchi Sea where the ice already shows as grey for reduced concentration, e.g. around 180 degrees longitude, 78 degrees latitude where holes are showing in an EOSDIS screenshot posted by jdallen on the 2016 Melting Season thread:
http://forum.arctic-sea-ice.net/index.php/topic,1493.msg81055.html#msg81055 (http://forum.arctic-sea-ice.net/index.php/topic,1493.msg81055.html#msg81055).
It looks like the storm winds might have made some of the tears more obvious though.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 23, 2016, 04:31:28 PM
Area keeps dropping making good speed.

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

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

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

The attached delta map  shows where the damage is done. Or just a wet surface after rain of course.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on June 23, 2016, 05:25:14 PM
Area keeps dropping making good speed.

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

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

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

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

Something seems a little off, Wipneus.

The shadow NSIDC was at 10.0219 on yesterdays update, but 10.4544 today?
Title: Re: 2016 sea ice area and extent data
Post by: be cause on June 23, 2016, 05:45:05 PM
A shadow CT area fall of over 850 000 sq km in 7 days and over 1 million in the last 10 .
Maintaining similar losses would leave an ice -free Arctic before the end of the melt season . At the rate of losses of the last 2 days we would have no ice to follow in only 25 days !
I am not expecting ice-free but most certainly a major North Pole Hole seems very likely and very news worthy when it happens ..
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 23, 2016, 05:48:57 PM

Something seems a little off, Wipneus.

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

More than a little BFTV. I was reading from the wrong file, thanks for catching this.
Title: Re: 2016 sea ice area and extent data
Post by: oren on June 23, 2016, 08:24:32 PM
A shadow CT area fall of over 850 000 sq km in 7 days and over 1 million in the last 10 .
Maintaining similar losses would leave an ice -free Arctic before the end of the melt season . At the rate of losses of the last 2 days we would have no ice to follow in only 25 days !
I am not expecting ice-free but most certainly a major North Pole Hole seems very likely and very news worthy when it happens ..

As we have seen recently, these large area drops in the middle of the pack do not mean the ice is gone, just that its top is wet/ponded. In a couple of days some of these drops might be reversed. Of course the ice has suffered in the meantime, but still it's risky to simply extrapolate these numbers.
Title: Re: 2016 sea ice area and extent data
Post by: CameraMan on June 23, 2016, 10:41:48 PM
As we have seen recently, these large area drops in the middle of the pack do not mean the ice is gone, just that its top is wet/ponded. In a couple of days some of these drops might be reversed.

Look at today's satellite photos.  Those aren't just melt ponds.  The ice is broken up with patches of open water.  It's not gone, but not looking healthy.
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on June 23, 2016, 11:48:42 PM
A shadow CT area fall of over 850 000 sq km in 7 days and over 1 million in the last 10 .
Maintaining similar losses would leave an ice -free Arctic before the end of the melt season . At the rate of losses of the last 2 days we would have no ice to follow in only 25 days !
I am not expecting ice-free but most certainly a major North Pole Hole seems very likely and very news worthy when it happens ..

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

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

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Farcticictn%2Fnowcast%2Fictn2016061718_2016061800_042_arcticictn.001.gif&hash=86a85f88dfbe1c18c2a8dd7a3e95dd91)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww7320.nrlssc.navy.mil%2FhycomARC%2Fnavo%2Farcticictn%2Fnowcast%2Fictn2016062218_2016062300_042_arcticictn.001.gif&hash=82e2e95c3c3adb37d753e2d124dba6ba)

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

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

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

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

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Focean.dmi.dk%2Fanim%2Fplots%2Fsst.arc.121.png&hash=153dd6b02f2f6051281048ba841a5c16)
Title: Re: 2016 sea ice area and extent data
Post by: Laurent on June 24, 2016, 11:58:18 AM
Personally, I think Hycom is good for the forecast but for the reality of the situation direct vision with normal RVB image is better (modis/worldview). For example, Hycom say there is still integrity along the path from Laptev to Beaufort when direct observation show none, that's because they have some difficulty with small flows (also it is designed for ship navigation, so it looks for the worse).

Beaufort big chunks are disintegrating.
http://go.nasa.gov/291w2XV (http://go.nasa.gov/291w2XV)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 24, 2016, 04:28:36 PM
Area is recovering (drying up) from the effects of the arctic low.

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

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

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

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


CT Area:
7,502,533 km2 (25 June [Day 0.4795])
Down 5,418,825 km2 (41.94%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
5,268,524 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 16,151 km2 (-.21%) from previous day.
Down 732,571 km2 (-9.03%) over past seven days (daily average: -104,653 km2).
Down 1,928,521 km2 (-17.32%) for June (daily average: -77,141 km2).
887,920 km2 below 2000s average for this date.
253,103 km2 below 2010s average for this date.
454,608 km2 below 2015 value for this date.
131,304 km2 above 2012 value for this date.
3rd lowest value for the date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' area numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 25, 2016, 04:37:59 PM
Century extent drop. Area takes it slow.

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

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


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

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

I let the attached delta map speak for itself.

Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on June 25, 2016, 04:53:23 PM
Century extent drop. Area takes it slow.

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

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

And just like that, SIA drops back to 4th place (behind 2010, 2012, and 2007), and out of the top three for the first time since March. And with both 2007 and 2012 losing around a million km2 over the next eight-day stretch, 2016 will have to really turn on the heat to stay close to the front of the pack.
Title: Re: 2016 sea ice area and extent data
Post by: CIP on June 25, 2016, 07:34:41 PM
Anyone care to comment on the apparent divergence between AMSR2 and NSDIC.
Title: Re: 2016 sea ice area and extent data
Post by: Neven on June 25, 2016, 08:54:11 PM
Century extent drop. Area takes it slow.

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

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

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

Jim, don't you mean 3rd place? According to my spreadsheet 2016 is currently around 98K lower than 2007. Or did you mean 2006 (which isn't part of my spreadsheet)?
Title: Re: 2016 sea ice area and extent data
Post by: Nick_Naylor on June 25, 2016, 10:11:17 PM
Since 2016 is a leap year, it depends on whether you're comparing by date, or by day of the year.

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

Neither method is 100% "fair" . . .
Title: Re: 2016 sea ice area and extent data
Post by: Neven on June 26, 2016, 12:31:29 AM
You're right, I did look at next day number for 2007, but didn't do it carefully enough.
Title: Re: 2016 sea ice area and extent data
Post by: RoxTheGeologist on June 26, 2016, 02:14:02 AM
Since 2016 is a leap year, it depends on whether you're comparing by date, or by day of the year.

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

Neither method is 100% "fair" . . .

Ideally the azimuth to the sun from the pole at midday would be the most "correct" method.. perhaps a small adjustment up or down of daily data would give a more accurate comparison; essentially mapping the discrete data to the continuous.
Title: Re: 2016 sea ice area and extent data
Post by: plinius on June 26, 2016, 12:00:02 PM
Simple solution would be to just give each year 365.25 days in the data and ignore human counting. Solution  would then be to have all years just plotted on this running scale (which shifts days by 0.25 pixels every year) and accept that only every fourth year matches up (quite) exactly. Anyway not a big deal to figure in that one day difference is about -80k km^2 at the moment, so a quarter day is 0.2/
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 26, 2016, 04:42:04 PM
Both area and extent are in the fast lane now.

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

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

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

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

The attached delta map will illustrate the numbers.
Title: Re: 2016 sea ice area and extent data
Post by: Steven on June 26, 2016, 04:59:51 PM
Tue 2016.4849  ...  7.306147

Back in 3rd place, behind 2010 and 2012:


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fnqpf4so.png&hash=5450e7b52d0955fbed00608424b53bbb)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 27, 2016, 04:59:00 PM
A bump in extent and a large drop of area in the CAB.

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

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

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

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

Judging from the atached delta map I think this is ice hovering around the 15% concentration. The concentration drops in the CAB are in a range from the Canadian islands to Svalbard.
Title: Re: 2016 sea ice area and extent data
Post by: abbottisgone on June 28, 2016, 03:55:43 AM
Since 2016 is a leap year, it depends on whether you're comparing by date, or by day of the year.

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

Neither method is 100% "fair" . . .
>:( >:(..such is the errata of all measurement : oh woe is the meaning of smallish beer!

(No, I didn't steal that quote off anyone!)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 28, 2016, 04:48:09 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

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

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

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

The attached delta map shows many details.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on June 28, 2016, 05:56:38 PM
Update for the week to June 25th

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

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

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FmyQWlev.png&hash=3aecd06f57d4e884524484a955626c37)

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

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FJAVQGcB.png&hash=e9f07f427325ab4cef0c9dbd729fde80)

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

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FIIJJIWp.png&hash=62b5c4c9b8aeead9a63f9e557152e4aa)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 29, 2016, 08:27:16 AM
I found this in my inbox this morning:

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

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

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

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

Now I don't know anything about "updated processing code" or "a new version of the input data", so I have to wait until further details are known. It could be very significant, eg if the new code does a better job at removing false coastal ice.
 
Title: Re: 2016 sea ice area and extent data
Post by: Neven on June 29, 2016, 09:52:22 AM
That's interesting. Thanks, Wipneus.
Title: Re: 2016 sea ice area and extent data
Post by: seaice.de on June 29, 2016, 10:20:08 AM

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

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

Maaß, N., L. Kaleschke, Improving passive microwave sea ice concentration algorithms for coastal areas - Applications to the Baltic Sea, Tellus A, Volume 62, Issue 4, Pages: 393–410, 2010
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 29, 2016, 05:21:47 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

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

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

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

The attached delta map illustrates the numbers.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on June 29, 2016, 05:42:13 PM
The 5 day trailing average, used for the NSIDC sea ice index, is now 2nd lowest - above 2010.
The is the first time since April 18th and it hasn't been lowest on record.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on June 30, 2016, 03:58:36 PM
Single day NSIDC extent is now 215k above 2010 and 53k above 2012
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on June 30, 2016, 04:23:39 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

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

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

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

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


CT Area:
7,049,632 km2 (01 July [Day 0.4958])
Down 5,871,726 km2 (45.44%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
4,815,623 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 44,636 km2 (-.63%) from previous day.
Down 469,052 km2 (-6.25%) over past seven days (daily average: -67,007 km2).
Down 44,636 km2 (-.4%) for July (daily average: -44,636 km2).
707,717 km2 below 2000s average for this date.
71,009 km2 below 2010s average for this date.
370,134 km2 below 2015 value for this date.
436,899 km2 above 2012 value for this date.
4th lowest value for the date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' area numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 01, 2016, 04:19:40 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.4904  -93.3  7.164613 +115.8 11.689271   +22.6 18.853884
Fri 2016.4932  -70.3  7.094268 +117.1 11.806354   +46.7 18.900622
Sat 2016.4959  -44.8  7.049490  +90.7 11.897066   +45.9 18.946556
Sun 2016.4986 -103.7  6.945792  +22.2 11.919313   -81.5 18.865105

Declining most are ESS (-29k), CAB (-26k) and Laptev (-16k).

Shadow NSIDC extent is 9.3344 a drop of -111.9. By extent the leading regions are Hudson (-29k), Laptev (-19k) and Chukchi (-15k).

The attached delta map shows exactly where the changes where.
Title: Re: 2016 sea ice area and extent data
Post by: Steven on July 01, 2016, 04:28:02 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

Sun 2016.4986  ... 6.945792 

This is the 5th lowest value for this date.  It is about 410k above 2012,  168k above 2010,  132k above 2007,  and 92k above the 2011 value for this date.


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F7X9lF87.png&hash=6328417991b9e447cb11af1e649c2f23)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on July 02, 2016, 03:58:52 PM
NSIDC extent, both the daily and 5 day trailing average, is now above 2010 and 2012.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 02, 2016, 05:49:03 PM
Strong declines, but some of it must be the first-of-the-month effect.

Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:
day  CT-date       NH               SH                Global
Fri 2016.4932  -70.3  7.094268 +117.1 11.806354   +46.7 18.900622
Sat 2016.4959  -44.8  7.049490  +90.7 11.897066   +45.9 18.946556
Sun 2016.4986 -103.7  6.945783  +22.4 11.919443   -81.3 18.865226
Mon 2016.5014 -202.8  6.742958   -1.6 11.917858  -204.4 18.660816

I estimate that the FOTM effect may attribute some -35k to the total, so still a strong decline. The CAB and ESS are particular strong: -93k and -53k. The CAA increased +24k.

Shadow NSIDC extent is now 9.1786 dropping -155.8k. The FOTM effect may as high as -100k, so todays drop is certainly inflated.

Attached is the delta map. Notice the red coasts around Okhotsk, Bering, Scandinavia, Newfoundland? That is ice no longer since the first of July.
The huge drop in concentration in the CAB and some increase near the Canadian islands is noticable.
 
Title: Re: 2016 sea ice area and extent data
Post by: Lord M Vader on July 02, 2016, 06:02:48 PM
WOW, a double century break by monday!  8)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on July 02, 2016, 06:33:11 PM
WOW, a double century break by monday!  8)

Didn't gain much, though; Day 0.5014 has been, historically, the day each year with the highest average daily area decrease. In fact, 10 out of the past 20 Day 5014s have seen a double century area loss, while the average decrease for the day over the past 30 years has been 184k km2. At any rate, both 2012 and 2014 lost more, so 2016 is now in 5th place for only the fifth time this year, and the first time since early February. The leaders: 2012, 2007, 2010, and, in fourth place, 2011.
Title: Re: 2016 sea ice area and extent data
Post by: Tor Bejnar on July 02, 2016, 06:44:33 PM
...
Didn't gain much, though; Day 0.5014 has been, historically, the day each year with the highest average daily area decrease. In fact, 10 out of the past 20 Day 5014s have seen a double century area loss, while the average decrease for the day over the past 30 years has been 184k km2. At any rate, both 2012 and 2014 lost more, so 2016 is now in 5th place for only the fifth time this year, and the first time since early February. The leaders: 2012, 2007, 2010, and, in fourth place, 2011.
Thanks, Jim.  Perspective is always helpful!
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on July 02, 2016, 07:15:00 PM
WOW, a double century break by monday!  8)

that are the data from yesterday, monday as far as i understood is just the day they will be officially published for 3 days back, would appreciate correction in case i see this wrong. however, could well be that:

here comes the cliff
i and others were expecting :-)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on July 03, 2016, 05:18:31 PM
Update for the week to July 2nd

The current 5 day trailing average is on 9,312,000km2 while the 1 day extent is at 9,110,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,529,000km2, an increase from -1,509,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at -225,000km2, a decrease from -437,000km2 last week. We're currently 3rd lowest on record, down from lowest as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FAhF7ZJS.png&hash=64f3f719493f6e45845d5ae8037ea712)

The average daily change over the last 7 days was -77.9k/day, compared to the long term average of -74.1k/day, and the 07, 11 and 12 average of -108.4k/day.
The average long term change over the next week is -85.4k/day, with the 07, 11, and 12 average being -126.9k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FM1mTxKO.png&hash=c2ff5d0c760f1ec4010809cdd2936c17)

The extent drop so far this July is the 25th smallest on record. To achieve the largest monthly loss, a drop of at least 115.8k/day is required (requiring >116.8k/day with with single day values), while the smallest loss requires a drop of less than 63.7k/day (<61.0k/day with single day values) and an average loss requires a drop of 83.6k/day (~85.3k/day with single day values).

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FVaBGajl.png&hash=cb5ebdcc39ae6cb30f74e43cf1c4a896)

The extent loss in June was the 17th largest on record, while the average extent was the lowest on record.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FIABhbTk.png&hash=935bccd00a7bdcad87098f98e319723b)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FqZ3Dh7z.png&hash=0bea84611c2f4c5c160ffd36d7dec1b6)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 03, 2016, 05:44:50 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.4959  -44.8  7.049490  +90.7 11.897066   +45.9 18.946556
Sun 2016.4986 -103.7  6.945783  +22.4 11.919443   -81.3 18.865226
Mon 2016.5014 -202.6  6.743183   -1.7 11.917756  -204.3 18.660939
Tue 2016.5041 -132.7  6.610508  -43.0 11.874745  -175.7 18.485253

Huge drop in the CAB, -79k; Hudson at distance -27k.

Shadow NSIDC extent  9.1101  dropping -68.5k.  Hudson fore runner -33k, Baffin -18k.

The attached delta map shows it all.
Title: Re: 2016 sea ice area and extent data
Post by: abbottisgone on July 04, 2016, 04:49:12 AM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FqZ3Dh7z.png&hash=0bea84611c2f4c5c160ffd36d7dec1b6)
The last graph is interesting if June has always been considered a 'stalling month' for ice loss!

<modified the comment to show what oren means; N.>
Title: Re: 2016 sea ice area and extent data
Post by: oren on July 04, 2016, 06:22:59 AM
The last graph is interesting if June has always been considered a 'stalling month' for ice loss!

Do you realize that you can comment without quoting the whole post?
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 04, 2016, 04:26:37 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.4986 -103.7  6.945783  +22.4 11.919443   -81.3 18.865226
Mon 2016.5014 -202.6  6.743183   -1.7 11.917756  -204.3 18.660939
Tue 2016.5041 -132.8  6.610378  -43.0 11.874765  -175.8 18.485143
Wed 2016.5068 -125.4  6.484964  -46.9 11.827910  -172.3 18.312874

Fourth century in a row, supported by CAB (-57k), Hudson (-38k) and CAA (-26k). ESS went up by +17k.

Shadow NSIDC extent is 9.0479  dropping -62.8k. Hudson (-32k) and Kara (-29k) lost most.

In the attached delta image the drop in concentration north of Ellesmere is noticeable.
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on July 04, 2016, 09:09:09 PM
I would think it is likely that this month sees the largest % decline of any July in history, possibly any month on record, though with August starting at an area baseline of 3-4MKM2 it could easily beat July's crash in terms of raw % lost.

With only 6.5MKM2 left, 30 more days of century drops leave us staring 3KM2 in the face...
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on July 04, 2016, 09:19:10 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.4986 -103.7  6.945783  +22.4 11.919443   -81.3 18.865226
Mon 2016.5014 -202.6  6.743183   -1.7 11.917756  -204.3 18.660939
Tue 2016.5041 -132.8  6.610378  -43.0 11.874765  -175.8 18.485143
Wed 2016.5068 -125.4  6.484964  -46.9 11.827910  -172.3 18.312874

Fourth century in a row, supported by CAB (-57k), Hudson (-38k) and CAA (-26k). ESS went up by +17k.

Shadow NSIDC extent is 9.0479  dropping -62.8k. Hudson (-32k) and Kara (-29k) lost most.

In the attached delta image the drop in concentration north of Ellesmere is noticeable.

hard to resist to refer to past postings haha... even worse than expected, even the 200k happened while temps above 80N are cooler than average. but the what are 0.2-0.3C less against the 20C less in january and almost through the entire winter. a perfect fit to general conditions, thinner, warmer, less solid and the likes.

@bbr2314 i see you smile big time :-)
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on July 04, 2016, 09:24:06 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.4986 -103.7  6.945783  +22.4 11.919443   -81.3 18.865226
Mon 2016.5014 -202.6  6.743183   -1.7 11.917756  -204.3 18.660939
Tue 2016.5041 -132.8  6.610378  -43.0 11.874765  -175.8 18.485143
Wed 2016.5068 -125.4  6.484964  -46.9 11.827910  -172.3 18.312874

Fourth century in a row, supported by CAB (-57k), Hudson (-38k) and CAA (-26k). ESS went up by +17k.

Shadow NSIDC extent is 9.0479  dropping -62.8k. Hudson (-32k) and Kara (-29k) lost most.

In the attached delta image the drop in concentration north of Ellesmere is noticeable.

hard to resist to refer to past postings haha... even worse than expected, even the 200k happened while temps above 80N are cooler than average. but the what are 0.2-0.3C less against the 20C less in january and almost through the entire winter. a perfect fit to general conditions, thinner, warmer, less solid and the likes.

@bbr2314 i see you smile big time :-)

I would be smiling if my ego were more important than the health of the planet... :)

At this point I think my assertion that this year will go ice-free is looking more and more likely... maybe we maintain a token million KM2 dispersed in old floes along the basin's periphery, but beyond the ice that's still 3-4M+ in thickness, it looks to me like everything else is going to go... note that on HYCOM/etc, the highest concentrations outside of what's pressed up against the CAA is along the ATL coast... right next to an impending scorch of SSTs surpassing 50F.

Equally important is the abysmal state of Greenland Sea ice, which has now allowed the fast ice N of Greenland to begin breaking up and joining what's being exported towards FRAM... another front pressing into the thickest ice there is. Perhaps what's more interesting/impactful over there besides the raw potential of sea ice loss is the water's encroachment into Greenland's glaciers, which are likely going to begin calving in an unprecedented fashion.
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on July 04, 2016, 09:33:24 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.4986 -103.7  6.945783  +22.4 11.919443   -81.3 18.865226
Mon 2016.5014 -202.6  6.743183   -1.7 11.917756  -204.3 18.660939
Tue 2016.5041 -132.8  6.610378  -43.0 11.874765  -175.8 18.485143
Wed 2016.5068 -125.4  6.484964  -46.9 11.827910  -172.3 18.312874

Fourth century in a row, supported by CAB (-57k), Hudson (-38k) and CAA (-26k). ESS went up by +17k.

Shadow NSIDC extent is 9.0479  dropping -62.8k. Hudson (-32k) and Kara (-29k) lost most.

In the attached delta image the drop in concentration north of Ellesmere is noticeable.

hard to resist to refer to past postings haha... even worse than expected, even the 200k happened while temps above 80N are cooler than average. but the what are 0.2-0.3C less against the 20C less in january and almost through the entire winter. a perfect fit to general conditions, thinner, warmer, less solid and the likes.

@bbr2314 i see you smile big time :-)

I would be smiling if my ego were more important than the health of the planet... :)

At this point I think my assertion that this year will go ice-free is looking more and more likely... maybe we maintain a token million KM2 dispersed in old floes along the basin's periphery, but beyond the ice that's still 3-4M+ in thickness, it looks to me like everything else is going to go... note that on HYCOM/etc, the highest concentrations outside of what's pressed up against the CAA is along the ATL coast... right next to an impending scorch of SSTs surpassing 50F.

Equally important is the abysmal state of Greenland Sea ice, which has now allowed the fast ice N of Greenland to begin breaking up and joining what's being exported towards FRAM... another front pressing into the thickest ice there is. Perhaps what's more interesting/impactful over there besides the raw potential of sea ice loss is the water's encroachment into Greenland's glaciers, which are likely going to begin calving in an unprecedented fashion.

- point about ego is taken

- still disagree on "Ice Free"

- generally see things similar

as to ice free, we both always pointed to the amount of energy that is in the system and sooner or later, which is probably now, must have a significant impact. following that very same path and considering the amount of ice that is totally in place by now ( volume ) i think that the energy that it would take to melt all that out within 70-80 days is simply not there, IMO it's as matter of factly not there, as the energy it takes for this years events
was getting in place last year already, i could search to 2015 post where i mentioned that the amount of energy surplus in the system must be excessive while as we all know that did not come to effects last year.

however i hope it's clear that i'm not sure, it's a thesis, let's see what happens and how knows all the positive and negative feedbacks that could overturn things once of a sudden, at least short term.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 05, 2016, 04:23:07 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Mon 2016.5014 -202.6  6.743183   -1.7 11.917756  -204.3 18.660939
Tue 2016.5041 -132.8  6.610378  -43.0 11.874765  -175.8 18.485143
Wed 2016.5068 -125.3  6.485084  -46.9 11.827910  -172.1 18.312994
Thu 2016.5096  +47.5  6.532555 +103.1 11.931030  +150.6 18.463585

Huge recovery of the CAB (+109k). CAA (-21k), Hudson (-18k) and ESS (-16k) are not enough to prevent an uptick in the total.

Shadow NSIDC is 8.9542  dropping -93.7k. Hudson (-23k) and Baffing (-17k) are the biggest decliners.

Attached delta map shows where exactly the changes were.

Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on July 05, 2016, 07:55:56 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Mon 2016.5014 -202.6  6.743183   -1.7 11.917756  -204.3 18.660939
Tue 2016.5041 -132.8  6.610378  -43.0 11.874765  -175.8 18.485143
Wed 2016.5068 -125.3  6.485084  -46.9 11.827910  -172.1 18.312994
Thu 2016.5096  +47.5  6.532555 +103.1 11.931030  +150.6 18.463585

Huge recovery of the CAB (+109k). CAA (-21k), Hudson (-18k) and ESS (-16k) are not enough to prevent an uptick in the total.

temps in the CAB droped 2-4C which makes this "recovery" most probably a matter of overfrozen melt ponds.

from the below pic one can see that even though most of the time things look very similar across various sources this time the discrepancy is astounding.

link to the site with non-cropped images and indices.
Title: Re: 2016 sea ice area and extent data
Post by: abbottisgone on July 06, 2016, 11:00:39 AM
The last graph is interesting if June has always been considered a 'stalling month' for ice loss!

Do you realize that you can comment without quoting the whole post?
Do you realise your buddys chose extinction?
Title: Re: 2016 sea ice area and extent data
Post by: abbottisgone on July 06, 2016, 11:04:15 AM
I would think it is likely that this month sees the largest % decline of any July in history, possibly any month on record, though with August starting at an area baseline of 3-4MKM2 it could easily beat July's crash in terms of raw % lost.

With only 6.5MKM2 left, 30 more days of century drops leave us staring 3KM2 in the face...
Yeh, well,.. if you're saying 3K is global market panic I think it's already been written in triplicate!
Title: Re: 2016 sea ice area and extent data
Post by: Neven on July 06, 2016, 11:24:17 AM
abbottisgone is gone for 30 days.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on July 06, 2016, 04:09:31 PM
Big drop on the NSIDC single day extent yesterday, down 154k. However, this was not enough to keep up with 2012, which we are now 166k behind.
We have dropped back below 2010 though, into 2nd lowest on record once again.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 06, 2016, 06:21:04 PM
Double century for CT-area.

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

day  CT-date       NH               SH                Global
Mon 2016.5014 -202.6  6.743183   -1.7 11.917756  -204.3 18.660939
Tue 2016.5041 -132.8  6.610378  -43.0 11.874765  -175.8 18.485143
Wed 2016.5068 -125.3  6.485084  -46.9 11.827910  -172.1 18.312994
Thu 2016.5096  +47.3  6.532421 +103.1 11.931036  +150.5 18.463457
Fri 2016.5123 -228.2  6.304220 +188.1 12.119158   -40.1 18.423378

Revenge of the CAB: -96k, and support from Laptev (-38k) and Kara (-29k).

Shadow NSIDC is 8.7998 a drop of -154.4k. Big drops in Hudson (-43k), Baffin (-37k), Kara (-26k) and Beaufort (-20k).

The attached delta map shows where the big concentration drops exactly were.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 07, 2016, 12:14:25 PM
Version 2.0 of NSIDC Sea Ice Index has arrived, including details what the difference with previous version 1.2 is.

 
Quote
NOAA@NSIDC is pleased to announce the release of Sea Ice Index Version 2. Improvements include using the most recently available version of the Goddard Space Flight Center (GSFC) input sea ice concentration data and revising three computations in the Sea Ice Index processing code. The new GSFC data have undergone additional manual quality control procedures at the GSFC that go farther to remove spurious ice. The GSFC data are available as their own data set from the NSIDC DAAC as Sea Ice Concentrations from Nimbus-7 SMMR and DMSP SSM/I-SSMIS Passive Microwave Data [http://nsidc.org/nsidc-0051]. The other three updates adjust calculations present in the old Sea Ice Index processing code that were in need of improvement. Because of these updates, minor changes in some of the ice extent and area numbers can be seen with the average change in the trends over all 12 months being on the order of 0.05 percent/decade (approximately 500 sq. km/year).

For a complete description of these changes and their effects, please see:
http://nsidc.org/data/docs/noaa/g02135_seaice_index/#jul-2016 (http://nsidc.org/data/docs/noaa/g02135_seaice_index/#jul-2016)

Access to the data and documentation is provided on the Sea Ice Index web site at: https://nsidc.org/data/seaice_index/ (https://nsidc.org/data/seaice_index/)

In practice there seem to be no big changes for the daily values. The biggest changes are in the past (as in 20th century). I have checked my (shadow) calculations for 2016 with those of NSIDC, and found perfect match (differences between +/- 500 km2, because NSIDC rounds at thousands of km2).

That may not be true for NSIDC's monthly averages (area and extent). That may have some influence on the September average value used by Neven's pol and SIPN's Sea Ice Outlook.
Since I don't calculate monthly values, I cannot comment on the actual changes this has.
Title: Re: 2016 sea ice area and extent data
Post by: Buddy on July 07, 2016, 12:52:35 PM
Quote
Shadow NSIDC is 8.7998 a drop of -154.4k. Big drops in Hudson (-43k), Baffin (-37k), Kara (-26k) and Beaufort (-20k).

Certainly looks like we are in "the meat" of the melt season.  A LOT of "crappy ice" could give us a month of sharp daily drops.  The central Russian coast now has a good "foothold" of open water and that should help.  Still expect SUB 2012 extent come mid September...
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on July 07, 2016, 01:16:49 PM
ADS-NIPR (IJIS) Extent:
8,401,287 km2 (06 July)
Down 5,541,220 km2 (39.74%) from 2016 maximum of 13,942,507 km2 on 29 February.
5,223,832 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 85,785 km2 (-1.01%) from previous day.
Down 632,442 km2  (-7.%) over past seven days (daily average: -90,349 km2).
Down 572,421 km2  (-4.68%) for July (daily average: -95,404 km2).
1,032,096 km2 below 2000s average for this date.
212,659 km2 below 2010s average for this date.
695,050 km2 below 2015 value for this date.
21,712 km2 below 2012 value for this date.
1st lowest year-to-date (01 January - 06 July) average.
1st lowest July to-date average.
1st lowest value for the date.
127 days this year (67.91% year-to-date) have recorded the lowest daily extent.
33 days (17.65%) have recorded the second lowest.
14 days (7.49%) have recorded the third lowest.
174 days in total (93.05%) have been among the lowest three on record.


CT Area:
6,304,220 km2 (07 July [Day 0.5123])
Down 6,617,138 km2 (51.21%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
4,070,211 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 228,201 km2 (-3.49%) from previous day.
Down 790,048 km2 (-11.21%) over past seven days (daily average: -112,864 km2).
Down 790,048 km2 (-7.09%) for July (daily average: -112,864 km2).
814,801 km2 below 2000s average for this date.
205,664 km2 below 2010s average for this date.
511,039 km2 below 2015 value for this date.
244,289 km2 above 2012 value for this date.
3rd lowest value for the date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' area numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 07, 2016, 04:16:49 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.5068 -125.3  6.485084  -43.0 11.874765  -168.3 18.359849
Thu 2016.5096  +47.3  6.532421  -46.9 11.827910    +0.5 18.360331
Fri 2016.5123 -228.3  6.304103 +103.1 11.931036  -125.2 18.235139
Sat 2016.5151 -149.5  6.154631 +188.1 12.119158   +38.7 18.273789

Biggest supporters are the CAB (-54k), ESS (-38k) and Baffin (-21k).

Shadow NSIDC extent is now 8.7799  a drop of -19.9k. Biggest drop is Baffin (-29k), Beaufort increased by +16k.

The attached delta map shows concentration drops in he central Arctic.
Title: Re: 2016 sea ice area and extent data
Post by: Steven on July 07, 2016, 04:38:42 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

Sat 2016.5151  ...  6.154631

Now in 3rd place, behind 2012 and 2010.  Here are the CT-area values for this date (day 0.5151):

2012      6.04  million km2
2010      6.15
2016     6.15
2007      6.19
2011      6.23
2015      6.65
2006      6.71
2014      6.73
2008      6.74
2013      6.77
...

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F5pC23sB.png&hash=724336f70b1e4ca7a42ec24ed8e30f21)
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on July 07, 2016, 05:56:48 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.5068 -125.3  6.485084  -43.0 11.874765  -168.3 18.359849
Thu 2016.5096  +47.3  6.532421  -46.9 11.827910    +0.5 18.360331
Fri 2016.5123 -228.3  6.304103 +103.1 11.931036  -125.2 18.235139
Sat 2016.5151 -149.5  6.154631 +188.1 12.119158   +38.7 18.273789

Biggest supporters are the CAB (-54k), ESS (-38k) and Baffin (-21k).

Shadow NSIDC extent is now 8.7799  a drop of -19.9k. Biggest drop is Baffin (-29k), Beaufort increased by +16k.

The attached delta map shows concentration drops in he central Arctic.

The hurricane-esque gyre that now dominates the entire basin is plainly obvious to me here but perhaps I am seeing things...
Title: Re: 2016 sea ice area and extent data
Post by: plinius on July 07, 2016, 06:05:31 PM
The hurricane-esque gyre that now dominates the entire basin is plainly obvious to me here but perhaps I am seeing things...

Correct, this is a common human perception issue to identify structures that are not really there. Great for preventing being eaten by a tiger, but also good for seeing ghosts, gods, conspiracies, or a hurricane in your water glass ;-).
http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticicespddrfnowcast.gif (http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticicespddrfnowcast.gif)
the centre of that drift curl does not coincide with your perceived hurricane (apart from that - never forget that clouds, rain bands, etc. imprint on the sea ice area, so you always have arcs there that are not real).
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on July 07, 2016, 09:09:11 PM

Correct, this is a common human perception issue to identify structures that are not really there. Great for preventing being eaten by a tiger, but also good for seeing ghosts, gods, conspiracies, or a hurricane in your water glass ;-)

you must have very good friends here that you get away with that condescending tone the entire day and without a forced sabatical. you discourage people which i think is the opposite of the purpose here, even if you were 100% right but at least half of your reasoning was plain wrong.
Title: Re: 2016 sea ice area and extent data
Post by: Neven on July 07, 2016, 11:48:36 PM
Magnamentis, I agree with you in principle, but bbr2314 has been dishing out himself too lately. Let's not turn this into a snowball. It's the Internet.

---

With CT's string of century breaks, my crude compactness maps are getting interesting. For instance, 2016 just dipped below 2012 on the CAMAS graph (Cryosphere Today area divided by MASIE):
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on July 08, 2016, 09:13:48 AM
Neven and Wipneus,
I have been following the ice concentration numbers for a while now, and I noticed that the higher resolution observations tend to show a record, while the lower resolution numbers do not.

For example, from the "Home brewed AMSR2" thread, Wipneus reported again that 2016 is in the lead for ice concentration (with only 2015 being almost equal in concentration, but 700k behind in extent) :

Extent: -92.6 (-700k vs 2015, -215k vs 2014, -401k vs 2013, +36k vs 2012)
Area: -220.4 (-667k vs 2015, -505k vs 2014, -641k vs 2013, -129k vs 2012)

The ice concentration map from Wipneus tends to show the same thing :
https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-compact-compare.png

High resolution (AMSR2 3.125 km resolution) is in the lead for 2016, while lower resolution (Bootstrap AMSR2 10 km, or NASA team SSIMS 25 km resolution) is lagging behind, and not showing 2016 in the lead (yet :o).

I've been thinking about that difference, and it seems to me that if high resolution shows lower ice concentration than lower resolution, considering that ice concentration in the main pack should not matter at which resolution it is measured, that maybe the ice edge is smaller (less fragmented) this year than in other years. But considering the fragmented ice edge in areas like the Beaufort, that explanation is not satisfying.

[edit] Come to think of it, if the ice edge is highly fragmented at the smaller than 25 km (or even 10 km) resolution, then highest resolution (3.125 km) will show more high-resolution pixels with low ice concentration than low-resolution pixels with low ice concentration, which will lower the high-resolution ice concentration and explain the observations.
Is that what is going on ?

Wondering if you have any rational explanation for this apparent difference in ice concentration from  the different resolution observations.
Title: Re: 2016 sea ice area and extent data
Post by: Peter Ellis on July 08, 2016, 10:03:33 AM
Rob:  Fundamentally, it means that areas that are of intermediate concentration in a low resolution source are being split into a mix of high concentration pixels and open water when you look at a higher resolution. Since melt ponds are of the order of metres across, they will not be resolved even by the highest resolution source - however openings and leads may be wide enough to be resolved at higher resolutions.

Ergo, I suspect what this means is that this year there is more open water within the pack and less melt ponding than in previous years.  That's consistent with the weather conditions which have favoured divergence over direct solar input.
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on July 08, 2016, 10:14:13 AM
Ergo, I suspect what this means is that this year there is more open water within the pack and less melt ponding than in previous years.  That's consistent with the weather conditions which have favoured divergence over direct solar input.

Thanks Peter, but that "this year there is more open water within the pack and less melt ponding than in previous years" does not explain the different observations from different resolution methods. After all, if open water this year is small (<3 km), it would gain the same ice concentration for high and low resolution methods. And if it is large (>25 km) it would gain more area of low ice concentration for low resolution methods, and thus we should see lower concentration for low resolution methods.

[edit] Maybe only a fragmentation in between (3 and 25 km) could explain the observations ?
Title: Re: 2016 sea ice area and extent data
Post by: Bill Fothergill on July 08, 2016, 12:21:06 PM
@Rob & Peter

I think I can see how this could happen - or I could simply be misunderstanding the issue. (It comes with the growing number of candles on the birthday cake - the local fire department now insist on being notified in advance!)

The thought experiment goes like this...

Imagine that "System A" has resolution down to 10 sq kms, whereas "System B" only has 40 sq km resolution. Now imagine a 40 sq km block that System B measures as having 14% concentration. Using the normal 15% threshold, this block would be counted as empty for both area and extent.

However, if System A looks at the same block, it might see three 10 sq km blocks, each with 15% concentration and a fourth 10 sq km block with 11%. This would therefore be register as 30 sq kms for extent and 4.5 sq kms for area.

If this situation gets repeated over a large section of the ice, then the higher-resolution system would be clocking up a significant contribution from the low-concentration peripheral regions. Should this be manifest over a sufficiently large region, it would have the effect of dragging the overall concentration downwards.


(NB It is not too difficult a mental exercise to change the conditions of the thought experiment such that the overall effect would be to increase the overall concentration, but that would be by eliminating smaller polynas within zones of already high concentration.)

Title: Re: 2016 sea ice area and extent data
Post by: Richard Rathbone on July 08, 2016, 12:51:48 PM
Some (and maybe most) is going to be down to the algorithm difference, not the resolution difference.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 08, 2016, 05:24:26 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.5096  +47.3  6.532421 +103.1 11.931036  +150.5 18.463457
Fri 2016.5123 -228.3  6.304103 +188.0 12.119058   -40.3 18.423161
Sat 2016.5151 -149.5  6.154631 +327.0 12.446055  +177.5 18.600686
Sun 2016.5178 -117.7  6.036904 +173.2 12.619298   +55.5 18.656202


CAB area dropped -67k, Hudson follows with -31k. Laptev increased by +22k.

Shadow NSIDC extent is 8.6858  dropping -94.1k. Hudson continues its nose dive drops -40k.  Chukchi is second with -20k.

Delta map attached for illustration.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 08, 2016, 06:00:55 PM
Neven and Wipneus,
I have been following the ice concentration numbers for a while now, and I noticed that the higher resolution observations tend to show a record, while the lower resolution numbers do not.

For example, from the "Home brewed AMSR2" thread, Wipneus reported again that 2016 is in the lead for ice concentration (with only 2015 being almost equal in concentration, but 700k behind in extent) :

Extent: -92.6 (-700k vs 2015, -215k vs 2014, -401k vs 2013, +36k vs 2012)
Area: -220.4 (-667k vs 2015, -505k vs 2014, -641k vs 2013, -129k vs 2012)

The ice concentration map from Wipneus tends to show the same thing :
https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-compact-compare.png

High resolution (AMSR2 3.125 km resolution) is in the lead for 2016, while lower resolution (Bootstrap AMSR2 10 km, or NASA team SSIMS 25 km resolution) is lagging behind, and not showing 2016 in the lead (yet :o).

I've been thinking about that difference, and it seems to me that if high resolution shows lower ice concentration than lower resolution, considering that ice concentration in the main pack should not matter at which resolution it is measured, that maybe the ice edge is smaller (less fragmented) this year than in other years. But considering the fragmented ice edge in areas like the Beaufort, that explanation is not satisfying.

[edit] Come to think of it, if the ice edge is highly fragmented at the smaller than 25 km (or even 10 km) resolution, then highest resolution (3.125 km) will show more high-resolution pixels with low ice concentration than low-resolution pixels with low ice concentration, which will lower the high-resolution ice concentration and explain the observations.
Is that what is going on ?

Wondering if you have any rational explanation for this apparent difference in ice concentration from  the different resolution observations.

Rob, first I am not aware about significant differences. Maybe because I am not paying attention enough. By extent 2016 3.125km UH extent is nearly the same as 2012 12.5km UH extent (fraction of a day difference). Same if I look at the ADS/Jaxa graph.

Resolution has some impact on extent, but not that much: I am comfortable with using the 12.5 km for 2012 and comparing it with 3.125 km calculations without any adjustment.
Regional extent is another matter, if you look at the Beaufort extent graph see how the lines for 10km Jaxa and 3.125 Uni Hamburg have separated because of the many leads and gaps that the latter can resolve but the first not. On total arctic extent the relative difefrence is much smaller.

And indeed I think that other factors, like the sea ice concentration algorithm are just as important. The 'NASA Team' algorithm used by NSIDC has the much lower concentration visible in the compactness graph.

Do not look at the CT-area numbers. I have summarized the questionable nature several times. Just the fact that 2016 has some more ice in lower latitudes (Hudson and Baffin) and less at higher (Beaufort, Barents) is enough to skew the rankings (low latitude ice is exaggerated, high latitudes underestimated.
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on July 09, 2016, 07:36:12 AM
Bill, Richard, Wipneus, Thanks, guys !

Bill, if I read your examples of System A and B correctly, then it shows what I suspected : If ice fragmentation is between 3 k and 25 km, then only can higher resolution method show a lower ice concentration than a lower resolution method.
But you are correct that the fragmentation has to be close to the 15% cut-off.
After all, is system A would have fragmentation variations around, say, 25% or 50%, then both high and low resolution methods would obtain the same “ice-concentration”…

Richard
Quote
Some (and maybe most) is going to be down to the algorithm difference, not the resolution difference.

Wipneus also commented that, but does either one of you know of such an algorithmic difference that obtains different ice concentration from the same source satellite data ?

Meanwhile, ice concentration for the NASA team algorithm is rapidly adjusting to the other (higher resolution) methods, in showing that 2016 ice concentration really is quite low, and possibly approaching record level :

https://14adebb0-a-62cb3a1a-s-sites.googlegroups.com/site/arctischepinguin/home/amsr2/grf/amsr2-compact-compare.png?attachauth=ANoY7cqRjXxWOpxudwqjcHAY9Xw1gDHGSly6aQOUmaaGVokfZ9VUQaZFKft6alqr8SFzrRJ2NTn9XmdMUOy8fWQiCJaWja95bHtTMpPiInPdQfrd3VCpUTLkYpCulz2P5O7oQyX7eYTCcXfdM36NdyfCouWcktL6g8iVD3khxL-eE7CSgrsPl6JatjFJfVvICIaDS3fCyy0bx45mN8rO_Q9iLWoIdyL6GaYSzDDU0ciPyYk6g10bcvSiFT5ZuC8jzefiMQJc0a66&attredirects=0
Title: Re: 2016 sea ice area and extent data
Post by: Andreas T on July 09, 2016, 01:04:55 PM
.....
Quote
Some (and maybe most) is going to be down to the algorithm difference, not the resolution difference.

Wipneus also commented that, but does either one of you know of such an algorithmic difference that obtains different ice concentration from the same source satellite data ?

......


have a look at https://www.researchgate.net/profile/Natalia_Ivanova5/publication/272794543_Satellite_passive_microwave_measurements_of_sea_ice_concentration_an_optimal_algorithm_and_challenges/links/54eeeedd0cf2e55866f3b64f.pdf (https://www.researchgate.net/profile/Natalia_Ivanova5/publication/272794543_Satellite_passive_microwave_measurements_of_sea_ice_concentration_an_optimal_algorithm_and_challenges/links/54eeeedd0cf2e55866f3b64f.pdf)
this is freely accessible, but very technical (not very accessible in that sense). But it gives an impression what algorithms do and how they can give different results by dealing with weather and surface conditions differently.
 It is also useful to be aware that the seaice concentration plots that we look at are the result of processes which have to interpret the brightness temperature data coming in (have a look at AMSR2 data on worldview) which do not give by themselves straightforward ice/ no ice information.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 09, 2016, 05:59:22 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Fri 2016.5123 -228.3  6.304103 +188.0 12.119058   -40.3 18.423161
Sat 2016.5151 -149.5  6.154631 +327.0 12.446055  +177.5 18.600686
Sun 2016.5178 -118.1  6.036550 +173.2 12.619207   +55.1 18.655757
Mon 2016.5205  -56.2  5.980352 +232.0 12.851168  +175.8 18.831520


None of the regions really stands out, Beaufort has the biggest loss at -18k.

Shadow NSIDC extent is 8.5593 a drop of -126.4k. Here Beaufort drops big way with -67k. Greenland Sea is second at a distant -23k.

The attached delta map illustrates these numbers. It reveals the CAB having many changes in local concentration that mostly cancel, so no big change there.
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on July 10, 2016, 11:00:51 AM
.....
Quote
Some (and maybe most) is going to be down to the algorithm difference, not the resolution difference.

Wipneus also commented that, but does either one of you know of such an algorithmic difference that obtains different ice concentration from the same source satellite data ?

have a look at https://www.researchgate.net/profile/Natalia_Ivanova5/publication/272794543_Satellite_passive_microwave_measurements_of_sea_ice_concentration_an_optimal_algorithm_and_challenges/links/54eeeedd0cf2e55866f3b64f.pdf (https://www.researchgate.net/profile/Natalia_Ivanova5/publication/272794543_Satellite_passive_microwave_measurements_of_sea_ice_concentration_an_optimal_algorithm_and_challenges/links/54eeeedd0cf2e55866f3b64f.pdf)
this is freely accessible, but very technical (not very accessible in that sense). But it gives an impression what algorithms do and how they can give different results by dealing with weather and surface conditions differently.
 It is also useful to be aware that the seaice concentration plots that we look at are the result of processes which have to interpret the brightness temperature data coming in (have a look at AMSR2 data on worldview) which do not give by themselves straightforward ice/ no ice information.

Thank you Andreas.
I always thought that the significant difference in methods from Wipneus concentration graphs :

https://14adebb0-a-62cb3a1a-s-sites.googlegroups.com/site/arctischepinguin/home/amsr2/grf/amsr2-compact-compare.png?attachauth=ANoY7cp_hktB3zd5pIuHTBDHQkFMea-QccNN1rwFNqyS49CbJah5Umem5XV5ZIGh1ViTiIxoayh6a7uz3VMEbwPzGG3SFaEHh6dyfNx_7Ajr2ur_LMkL8fZ5WBAlTgTPgd9Pd9RPwTAl9XjsOJFbzMweyDi0ATaDeci2aMkG5QLoz-QPQay6r6GwLJb6i1VoIyQzf79S9T2WmL5yrayIyxCp5UjNrKXgck0c_BEDMF5PgYSu7go55UFk2qmXma1U1h-bc7SxlGnS&attredirects=1 (https://14adebb0-a-62cb3a1a-s-sites.googlegroups.com/site/arctischepinguin/home/amsr2/grf/amsr2-compact-compare.png?attachauth=ANoY7cp_hktB3zd5pIuHTBDHQkFMea-QccNN1rwFNqyS49CbJah5Umem5XV5ZIGh1ViTiIxoayh6a7uz3VMEbwPzGG3SFaEHh6dyfNx_7Ajr2ur_LMkL8fZ5WBAlTgTPgd9Pd9RPwTAl9XjsOJFbzMweyDi0ATaDeci2aMkG5QLoz-QPQay6r6GwLJb6i1VoIyQzf79S9T2WmL5yrayIyxCp5UjNrKXgck0c_BEDMF5PgYSu7go55UFk2qmXma1U1h-bc7SxlGnS&attredirects=1)

between the NASA Team algorithm on SSMIS 25 km and Bootstrap on AMSR2 10 km (as well as Uni Hamburg ASI algorithm on AMSR2 3.125 km) was caused by the resolution difference of these three methods.

But after reading the paper you referenced, and some quick "back-of-the-envelope" calculations on how much "resolution" can affect "ice concentration", I'm not so sure any more.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 10, 2016, 04:34:36 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.5151 -149.5  6.154631 +327.0 12.446055  +177.5 18.600686
Sun 2016.5178 -118.1  6.036550 +173.2 12.619207   +55.1 18.655757
Mon 2016.5205  -56.1  5.980457 +232.2 12.851426  +176.1 18.831883
Tue 2016.5233 -156.3  5.824159 +140.1 12.991487   -16.2 18.815646

The big decline is lead by CAB (-58k), ESS (-35k) and Hudson (-25k).

Shadow NSIDC extent is now 8.5125 a drop of -46.9k. Hudson drops -52k, Beaufort 'recovers' +34k.

The attached delta map shows the details.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 10, 2016, 04:48:48 PM

I always thought that the significant difference in methods from Wipneus concentration graphs :

https://14adebb0-a-62cb3a1a-s-sites.googlegroups.com/site/arctischepinguin/home/amsr2/grf/amsr2-compact-compare.png?attachauth=ANoY7cp_hktB3zd5pIuHTBDHQkFMea-QccNN1rwFNqyS49CbJah5Umem5XV5ZIGh1ViTiIxoayh6a7uz3VMEbwPzGG3SFaEHh6dyfNx_7Ajr2ur_LMkL8fZ5WBAlTgTPgd9Pd9RPwTAl9XjsOJFbzMweyDi0ATaDeci2aMkG5QLoz-QPQay6r6GwLJb6i1VoIyQzf79S9T2WmL5yrayIyxCp5UjNrKXgck0c_BEDMF5PgYSu7go55UFk2qmXma1U1h-bc7SxlGnS&attredirects=1 (https://14adebb0-a-62cb3a1a-s-sites.googlegroups.com/site/arctischepinguin/home/amsr2/grf/amsr2-compact-compare.png?attachauth=ANoY7cp_hktB3zd5pIuHTBDHQkFMea-QccNN1rwFNqyS49CbJah5Umem5XV5ZIGh1ViTiIxoayh6a7uz3VMEbwPzGG3SFaEHh6dyfNx_7Ajr2ur_LMkL8fZ5WBAlTgTPgd9Pd9RPwTAl9XjsOJFbzMweyDi0ATaDeci2aMkG5QLoz-QPQay6r6GwLJb6i1VoIyQzf79S9T2WmL5yrayIyxCp5UjNrKXgck0c_BEDMF5PgYSu7go55UFk2qmXma1U1h-bc7SxlGnS&attredirects=1)

between the NASA Team algorithm on SSMIS 25 km and Bootstrap on AMSR2 10 km (as well as Uni Hamburg ASI algorithm on AMSR2 3.125 km) was caused by the resolution difference of these three methods.

But after reading the paper you referenced, and some quick "back-of-the-envelope" calculations on how much "resolution" can affect "ice concentration", I'm not so sure any more.

That is true. The drop in "compactness" is mostly caused by the effects of liquid water: from dry ice/snow to wet ice/snow to melt ponds. NSIDC sea ice concentration, calculated by the NASA Team algorithm, is more sensitive than the other two methods used in that graph.

The effects of resolving leads and open water are there and similar, but not that big.
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on July 10, 2016, 06:14:23 PM
day  CT-date       NH               SH                Global
Sat 2016.5151 -149.5  6.154631 +327.0 12.446055  +177.5 18.600686
Sun 2016.5178 -118.1  6.036550 +173.2 12.619207   +55.1 18.655757
Mon 2016.5205  -56.1  5.980457 +232.2 12.851426  +176.1 18.831883
Tue 2016.5233 -156.3  5.824159 +140.1 12.991487   -16.2 18.815646
[/tt]

that makes accounts for 120k per day over the last 4 days, so much to lack of momentum. i think that most people don't pay enough attention that 20% ice coverage still counts full to extent, hence in this phase
area is the better indicator of what's going on. extent can theoretically drop from 100 to zero in almost no time once the last cm of ice cover is reached. that's was an example to make my point not sayin' that the ice will go to zero extent withing a few days, hence "theoretically possible" not likely to happen of course.
Title: Re: 2016 sea ice area and extent data
Post by: Tor Bejnar on July 10, 2016, 08:18:47 PM
I do get tired of reading absolutest statements like "area is the better indicator of what's going on."

Area is a great indicator of some things, and a so-so indicator of other things. 

If you want a clue about what the current heat gain in the Arctic is, area is an indicator, along with cloud cover and time of year and latitude (and probably some others), you'll want to track.

If you want to know how much of the Arctic is covered in ice, you will want to pick a number somewhere between "area" and "extent".  All those melt ponds in July are counted as being water and not ice, when, in fact, the sea is completely covered with ice under every single melt pond.  The "area" numbers are a great indicator of actual ice area only after the establishment of freezing surface temperatures in ~late September and October and before the onset of new melt ponds in ~May.

If one's concern is shipping, extent maps are probably the best indicator of where it is safe to float.  For anyone wanting to know if they need a parka before stepping out of their heated ship's cabin, a thermometer's reading is probably the best indicator of "what's going on."
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on July 10, 2016, 09:03:49 PM
Update for the week to July 9th

The current 5 day trailing average is on 8,667,000km2 while the 1 day extent is at 8,512,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,576,000km2, an increase from -1,529,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at +19,000km2, an decrease from -225,000km2 last week. We're currently 3rd lowest on record, the same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FXsEv5H6.png&hash=053178fbf110d2ecc9a0c450ab0ed41f)

The average daily change over the last 7 days was -92.0k/day, compared to the long term average of -85.4k/day, and the 07, 11 and 12 average of -126.9k/day.
The average long term change over the next week is -82.9k/day, with the 07, 11, and 12 average being -111.3k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FTZmbLUO.png&hash=7117914315441b0327c49840565550de)

The extent drop so far this July is the 14th largest on record. To achieve the largest monthly loss, a drop of at least 123.3k/day is required (requiring >127.8k/day with with single day values), while the smallest loss requires a drop of less than 54.6k/day (<52.4k/day with single day values) and an average loss requires a drop of 84.5k/day (~85.2k/day with single day values).

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F393aLIr.png&hash=2dbc9ec090ea467ffb93b2e351df10eb)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 11, 2016, 05:03:19 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.5178 -118.1  6.036550 +173.2 12.619207   +55.1 18.655757
Mon 2016.5205  -56.1  5.980457 +232.2 12.851426  +176.1 18.831883
Tue 2016.5233 -156.1  5.824326 +140.1 12.991531   -16.0 18.815857
Wed 2016.5260 -108.8  5.715556  +14.6 13.006105   -94.2 18.721661


The century is supported by the CAB (-58k) and Hudson (-31k).

Shadow NSIDC extent is 8.4181 dropping  -94.4k. Hudson is star: -76k. Chukchi increased +24k, Beaufort dropped -20k.

Attached delta map shows what is going on.

Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on July 12, 2016, 08:24:26 AM
That is true. The drop in "compactness" is mostly caused by the effects of liquid water: from dry ice/snow to wet ice/snow to melt ponds. NSIDC sea ice concentration, calculated by the NASA Team algorithm, is more sensitive than the other two methods used in that graph.

The effects of resolving leads and open water are there and similar, but not that big.

Thank you Wipneus. That makes total sense.
It explains two observations in the concentration graphs :

- NASA team algorithm on SSMIS drops far lower than Bootstrap AMSR2 in the graphs during the melting season, accounting for the higher sensitivity to liquid water on the ice.
- In 2016, with more ice fragmentation, ASI AMSR2 shows 2016 in the lead (lowest concentration), but since there was less melt-onset (due to these persistent lows in June) there was less wet snow, and fewer melting ponds, so NASA Team SSMIS for 2016 was in the middle of the pack.
- There is still a (relative) difference between ASI and Bootstrap on AMSR2 data. ASI showing 2016 in the lead for ice concentration, while Bootstrap AMSR2 showing 2016 at a more moderate ranking.

It may be interesting to run NASA Team's algorithm on AMSR2 to see if this explains the differences in ice concentration, and how much (if any) of the difference is caused by difference in resolution.

[edit] From these findings and the concentration maps that you publish, can we cautiously conclude that 2016 is in the lead when it comes to lead/polynia/open water next to ice, while when it comes to overall water on the ice (including wet snow and melting ponds) that it is in the middle of the pack, and not setting records ?
Title: Re: 2016 sea ice area and extent data
Post by: Richard Rathbone on July 12, 2016, 12:20:28 PM
From these findings and the concentration maps that you publish, can we cautiously conclude that 2016 is in the lead when it comes to lead/polynia/open water next to ice, while when it comes to overall water on the ice (including wet snow and melting ponds) that it is in the middle of the pack, and not setting records ?

I'm not sure about the leads, but that's how I get an idea of melt pond behavior prior to Schroeder's analysis coming out with the SIPN prediction.
Title: Re: 2016 sea ice area and extent data
Post by: Neven on July 12, 2016, 06:59:21 PM
Richard, I have some info on that in my latest blog post: 2016 Melting momentum, part 3 (http://neven1.typepad.com/blog/2016/07/2016-melting-momentum-part-3.html)
Title: Re: 2016 sea ice area and extent data
Post by: Richard Rathbone on July 12, 2016, 10:34:32 PM
Richard, I have some info on that in my latest blog post: 2016 Melting momentum, part 3 (http://neven1.typepad.com/blog/2016/07/2016-melting-momentum-part-3.html)

That looks like "stick" rather than "twist" to me but for the August poll I will be taking a lot of notice of what the Slater projection looks like then.
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on July 13, 2016, 05:27:20 AM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.5178 -118.1  6.036550 +173.2 12.619207   +55.1 18.655757
Mon 2016.5205  -56.1  5.980457 +232.2 12.851426  +176.1 18.831883
Tue 2016.5233 -156.1  5.824326 +140.1 12.991531   -16.0 18.815857
Wed 2016.5260 -108.8  5.715556  +14.6 13.006105   -94.2 18.721661


The century is supported by the CAB (-58k) and Hudson (-31k).

Shadow NSIDC extent is 8.4181 dropping  -94.4k. Hudson is star: -76k. Chukchi increased +24k, Beaufort dropped -20k.

Attached delta map shows what is going on.

Would you be able to provide 2012's area benchmarks for 8/1 and 8/16? Just curious!

On current trajectory, I think sub-4MKM2 is very doable by 8/1. How far below determines whether we end up merely somewhat below 2012 or nearly ice-free under 1M KM2 @ minimum. If we are near 3.5M KM2 by 8/1, going to be in even bigger trouble.
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on July 13, 2016, 11:14:58 AM
Quote
On current trajectory, I think sub-4MKM2 is very doable by 8/1.

On current trajectory, I don't see that there is any way to get sub-4Mkm^2 by 8/1.
https://ads.nipr.ac.jp/vishop/vishop-extent.html?N
Title: Re: 2016 sea ice area and extent data
Post by: Bill Fothergill on July 13, 2016, 11:51:50 AM
Quote
On current trajectory, I think sub-4MKM2 is very doable by 8/1.

On current trajectory, I don't see that there is any way to get sub-4Mkm^2 by 8/1.
https://ads.nipr.ac.jp/vishop/vishop-extent.html?N


Rob,
When bbr mentioned the possibility of a sub-4 by the beginning of August, I'm pretty sure this was referring to the shadow-CT value kindly provided by Wipneus, rather than the ADS extent value to which you linked . As the shadow-CT area now (as of Wed 13th July) stands at 5.716 million sq kms, it is certainly within the bounds of possibility for the drop rate over the next 18 days to average about 95k/day.

I'm not sticking my neck out and saying that this will happen, but I don't think it can be ruled out.



...
Would you be able to provide 2012's area benchmarks for 8/1 and 8/16? Just curious!
...

Links to the actual CT numbers (NH, SH & Global) are contained within the Sea Ice Graphs link on the ASIB.
https://sites.google.com/site/arcticseaicegraphs/

The values for the dates you requested were 3.787 & 2.942 respectively.
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on July 13, 2016, 02:44:20 PM
Quote
On current trajectory, I think sub-4MKM2 is very doable by 8/1.

On current trajectory, I don't see that there is any way to get sub-4Mkm^2 by 8/1.
https://ads.nipr.ac.jp/vishop/vishop-extent.html?N


Rob,
When bbr mentioned the possibility of a sub-4 by the beginning of August, I'm pretty sure this was referring to the shadow-CT value kindly provided by Wipneus, rather than the ADS extent value to which you linked . As the shadow-CT area now (as of Wed 13th July) stands at 5.716 million sq kms, it is certainly within the bounds of possibility for the drop rate over the next 18 days to average about 95k/day.

I'm not sticking my neck out and saying that this will happen, but I don't think it can be ruled out.



...
Would you be able to provide 2012's area benchmarks for 8/1 and 8/16? Just curious!
...

Links to the actual CT numbers (NH, SH & Global) are contained within the Sea Ice Graphs link on the ASIB.
https://sites.google.com/site/arcticseaicegraphs/

The values for the dates you requested were 3.787 & 2.942 respectively.

Thanks Bill!

I think 2016 will be about even or slightly lower than 2012 come the first with a much larger lead by the 16th. I will say 3.6MKM2 and 2.5MKM2 respectively.
Title: Re: 2016 sea ice area and extent data
Post by: Bill Fothergill on July 13, 2016, 03:36:24 PM
@ Rob,

I'm afraid the old grey matter went out for a stroll there. In order to substantiate what I had said in my above post, I meant (but failed lamentably in the intention) to include the following from Wipneus' running shadow-CT numbers...

On 2016.4986, the shadow-CT value was 6.946 million sq kms, but, by 2016.5260 this had dropped to 5.716 million sq kms. Averaged over that 10-day period, the resultant daily loss works out at about 123k/day.

Although you were correct in pointing out that the ADS drop rate is/was less impressive (about 89k/day over the same 10 day period) this could be another example of the two sets of figures showing apparently divergent behaviour as the concentration ratio alters.


@ bbr2314

I should have posted a slight "health warning" regarding date formats. Using the standard CT dating conventions, the date YYYY.5260 should actually relate to the 11th of July, not the 13th.

There is a trap for the unwary in that, for example, 2016.0000 means the 31st Dec 2015, and NOT the 1st of Jan 2016, as one might otherwise expect. (The reasons are historic, but primarily relate to the limited computing power available to the Polar Research team at UIUC in the dim and distant past.)

The values I gave (3.787 and 2.942) were for the 1st and 16th of August in 2012. The date stamp for each of these dates should read approximately 2016.5836 and 2016.6246 when we finally get there next month. (NB the daily increment value ranges from 0.0026 - 0.0029, but since 2012 was also a Leap Year, I would expect the values to match more or less exactly.)

Therefore, although Wipneus' latest figure (2016.5260 <> 5.716 million sq kms) appears to relate to the 13th July, it actually equates historically to values for the 11th. The 1st of August is 19 days on from the 13th July, but the same offset taken from the 11th July only takes us up to July 30th. Similarly, a 34-day offset from 13th July gives your 16th August date, but, from the 11th July, this would equate to the 14th August.

The values for July 30 2012 (2012.5781) and Aug 14 2012 (2012.6191) were 4.085 and 2.986 million sq kms respectively.
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on July 13, 2016, 06:11:24 PM
Thanks Bill!

Today's numbers should be particularly interesting since we didn't get an update yesterday. If the benchmark for 2012 is 4.1M by 8/1 I think that is very doable indeed, and by that point 2016 should be opening quite a lead. Again, I will call for 3.6M km2 on that date this year for anyone who wants to rake me across the coals if I'm wrong.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 14, 2016, 07:59:58 AM
NSIDC servers are back. This is the report from sea ice concentration dated 2016-07-12.

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


day  CT-date       NH               SH                Global
Tue 2016.5233 -156.1  5.824326 +140.1 12.991531   -16.0 18.815857
Wed 2016.5260 -108.8  5.715507  +14.5 13.006019   -94.3 18.721526
Thu 2016.5288 -127.6  5.587861   -4.2 13.001869  -131.8 18.589730
Fri 2016.5315  -82.5  5.505383  -64.0 12.937885  -146.5 18.443268


Shadow NSIDC is now 8.0671 that is a drop of -170.8 (after a drop of -1801.1 the day before).

Half of the declines (area and extent) are in the Hudson region, where the phrase "falling of a cliff" is only a small exaggeration. Chukchi, ESS and CAB (just area) follow at distance.

The delta map is back too.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on July 14, 2016, 12:56:15 PM
NSIDC servers are back. This is the report from sea ice concentration dated 2016-07-12.

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


day  CT-date       NH               SH                Global
Tue 2016.5233 -156.1  5.824326 +140.1 12.991531   -16.0 18.815857
Wed 2016.5260 -108.8  5.715507  +14.5 13.006019   -94.3 18.721526
Thu 2016.5288 -127.6  5.587861   -4.2 13.001869  -131.8 18.589730
Fri 2016.5315  -82.5  5.505383  -64.0 12.937885  -146.5 18.443268

That shadow SIA reading for Day 0.5315 is lower than the SIA annual minimum recorded in 1980. One down, 36 to go...
Title: Re: 2016 sea ice area and extent data
Post by: Bill Fothergill on July 14, 2016, 02:28:38 PM

That shadow SIA reading for Day 0.5315 is lower than the SIA annual minimum recorded in 1980. One down, 36 to go...


Well spotted, that man!
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 14, 2016, 05:34:54 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.5260 -108.8  5.715507  +14.5 13.006019   -94.3 18.721526
Thu 2016.5288 -127.6  5.587861   -4.2 13.001869  -131.8 18.589730
Fri 2016.5315  -82.6  5.505247  -64.0 12.937879  -146.6 18.443126
Sat 2016.5342  -93.5  5.411760  -51.9 12.885998  -145.4 18.297758



Most of that decline is in the ESS: -55k.

Shadow NSIDC is 7.9235 dropping -143.7. Chukchi went down -55k, followed by CAA, CAB and Hudson (all around -20k).

The delta map shows the details.
Title: Re: 2016 sea ice area and extent data
Post by: seaicesailor on July 14, 2016, 05:49:08 PM
Correct me if I am wrong but that is about 600k of extent gone in 4 days
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on July 14, 2016, 06:06:34 PM
Correct me if I am wrong but that is about 600k of extent gone in 4 days

You're right. About 589k in 4 days, 495k in the last 3 (with daily NSIDC extent). Still above 2012 and 2011 though.
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on July 14, 2016, 08:37:24 PM
ok, so can anyone provide the number that is officially considered a "cliff" so that i can learn to use terms correctly or refer to such a statement. yesterday there was a discussions where some guys said the cliff does/did not happen and is this a one. so if i'm wrong here i  at least wanna know for the future and the other way
would of course be even better :-)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on July 14, 2016, 09:33:22 PM
ok, so can anyone provide the number that is officially considered a "cliff" so that i can learn to use terms correctly or refer to such a statement. yesterday there was a discussions where some guys said the cliff does/did not happen and is this a one. so if i'm wrong here i  at least wanna know for the future and the other way
would of course be even better :-)

I don't know about "official", but the mega melt weeks (>1m in 7 days) are usually rare enough and long lasting enough to be considered a cliff, rather than a step.

Using the single day NSIDC data, which is influenced somewhat by the correction at the start of July,  we didn't have the first mega melt week until 1991 (which had 2 with overlapping dates). The next occurrence wasn't until 2005, which had 1.
2007 changed things with 6 (overlapping dates again). Of the years from 2008 to 2015, 5/8 saw mega melt weeks.
2012 was the first to have 2 completely separate mega melt weeks, both the earliest and latest on record in June and in August.

The largest 7 day melt period so far this year is the latest one, at -733k, which is provisionally the smallest since 2006 and 9th smallest on record. This will probably change over the next few days though.

So yeah. I go with defining a cliff as being a loss of 1 million km2 or greater over 7 days, the mega melt week.
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on July 14, 2016, 09:38:22 PM
ok, very well, that makes sense, i took it more optical, some kind of steepening from the previous main
direction of the curve but i think what you elaborated can be well used as a definition for now. thanks, very much appreciated.

Title: Re: 2016 sea ice area and extent data
Post by: Tensor on July 15, 2016, 06:20:24 AM
ok, very well, that makes sense, i took it more optical, some kind of steepening from the previous main
direction of the curve but i think what you elaborated can be well used as a definition for now. thanks, very much appreciated.
If the last three days would have occurred prior to our comments, I wouldn't have argued with your use of the word cliff.  Although I think Born's definition is a pretty good one.   
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on July 15, 2016, 01:35:52 PM
ADS-NIPR Extent:
7,611,399 km2 (14 July)
Down 6,331,108 km2 (45.41%) from 2016 maximum of 13,942,507 km2 on 29 February.
4,433,944 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 145,972 km2 (-1.88%) from previous day.
Down 735,737 km2  (-8.81%) over past seven days (daily average: -105,105 km2).
Down 1,362,309 km2  (-11.13%) for July (daily average: -97,308 km2).
1,154,419 km2 below 2000s average for this date.
211,858 km2 below 2010s average for this date.
644,187 km2 below 2015 value for this date.
65,254 km2 below 2012 value for this date.
Lowest year-to-date (01 January - 14 July) average.
Lowest July to-date average.
2nd lowest value for the date.
128 days this year (65.64% year-to-date) have recorded the lowest daily extent.
34 days (17.44%) have recorded the second lowest.
19 days (9.74%) have recorded the third lowest.
181 days in total (92.82%) have been among the lowest three on record.


CT Area:
5,411,760 km2 (15 July [Day 0.5343])
Down 7,509,598 km2 (58.12%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
3,177,751 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 93,487 km2 (-1.7%) from previous day.
Down 742,871 km2 (-12.31%) over past seven days (daily average: -106,124 km2).
Down 1,682,508 km2 (-15.11%) for July (daily average: -112,167 km2).
971,742 km2 below 2000s average for this date.
283,265 km2 below 2010s average for this date.
457,741 km2 below 2015 value for this date.
308,751 km2 above 2012 value for this date.
2nd lowest value for the date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' shadow area numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!

Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 15, 2016, 06:51:13 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.5288 -127.6  5.587861   -4.2 13.001869  -131.8 18.589730
Fri 2016.5315  -82.6  5.505247  -64.0 12.937879  -146.6 18.443126
Sat 2016.5342  -93.5  5.411760  -51.9 12.886004  -145.4 18.297764
Sun 2016.5370  -66.7  5.345110  -66.6 12.819450  -133.2 18.164560


Biggest decline in the CAA (-24k), followed by Baffin (-19k) and Chukchi (-17k).

Shadow NSIDC is now 7.8817 dropping -41.8k. Strong declines in Chukchi (-40k), Beaufort (-37k) and Baffin (-23k). Upticks in Hudson where the hoovering around 15% seems to have started (+27k) and ESS (+25k).

As always, there is the delta map:
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on July 15, 2016, 08:06:52 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.5288 -127.6  5.587861   -4.2 13.001869  -131.8 18.589730
Fri 2016.5315  -82.6  5.505247  -64.0 12.937879  -146.6 18.443126
Sat 2016.5342  -93.5  5.411760  -51.9 12.886004  -145.4 18.297764
Sun 2016.5370  -66.7  5.345110  -66.6 12.819450  -133.2 18.164560


FWIW, 2016 area is now lower than the annual minimums set in 1980, 1983, and 1986.

As always, thanks Wipneus!
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 17, 2016, 06:28:20 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.5342  -93.5  5.411760  -51.9 12.886004  -145.4 18.297764
Sun 2016.5370  -66.5  5.345257  -66.2 12.819805  -132.7 18.165062
Mon 2016.5397  -12.8  5.332489  +42.1 12.861951   +29.4 18.194440
Tue 2016.5425  -91.8  5.240669   +5.3 12.867237   -86.5 18.107906



Big drop of area in the CAB (-79k), Beaufort increased by +26k.

Shadow NSIDC extent is now 7.8312 an increase of +23.3k. Big increases in the Beaufort (+107k) and Chukchi (+34k). Extent dropped in the ESS (-36k), Hudson (-27k) and CAA (-26k).

Of course, there is a delta map as well.
Title: Re: 2016 sea ice area and extent data
Post by: Steven on July 17, 2016, 08:25:54 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

Tue 2016.5425    ...   5.240669

Third lowest, behind 2012 and 2007:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fw3tBg2i.png&hash=829bf30977475e236b904342e856807c)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on July 18, 2016, 09:36:27 AM
Update for the week to July 16th

The current 5 day trailing average is on 7,902,000km2 while the 1 day extent is at 7,831,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,760,000km2, an increase from -1,576,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at +33,000km2, an increase from +19,000km2 last week. We're currently 3rd lowest on record, the same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FDCbHyob.png&hash=12dd4e230486d2882fd6db2ec77e2419)

The average daily change over the last 7 days was -109.3k/day, compared to the long term average of -82.9k/day, and the 07, 11 and 12 average of -111.3k/day.
The average long term change over the next week is -89.4k/day, with the 07, 11, and 12 average being -85.6k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FcuA8KGS.png&hash=7408c6e852fbadc90b9161b6164cd091)

The extent loss so far this July is the 10th largest on record. To achieve the largest monthly loss, a drop of at least 129.7k/day is required (requiring >144.1k/day with with single day values), while the smallest loss requires a drop of less than 29.3k/day (<28.3k/day with single day values) and an average loss requires a drop of 73.0k/day (~78.7k/day with single day values).

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FHtbHtNK.png&hash=b409ad4f32e3ed447dca0dffc93f312c)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on July 18, 2016, 01:02:15 PM
To accompany BFTV's charts:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimage.prntscr.com%2Fimage%2Fc72b3f508eeb4dd18854b59bc70eb30d.png&hash=06c05aa2483cc87cb3c264cad3c8bda8)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimage.prntscr.com%2Fimage%2Fd5a470f74870464b956ffed216946532.png&hash=506bb218b843c410987c420a685d7e00)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on July 18, 2016, 04:03:35 PM
Daily NSIDC extent has hit a wall and is now 4th lowest on record.

Average drop with the single day extent values last 4 days = -19.3k/day (81-10 avg is -87k/day).
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 18, 2016, 04:40:48 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.5370  -66.5  5.345257  -66.2 12.819805  -132.7 18.165062
Mon 2016.5397  -12.8  5.332489  +42.1 12.861951   +29.4 18.194440
Tue 2016.5425  -91.8  5.240649   +5.7 12.867640   -86.2 18.108289
Wed 2016.5452 -129.5  5.111185  -20.6 12.847038  -150.1 17.958223



Regionally CAB and Laptev are the main sponsors: -53k and -44k.

Shadow NSIDC extent is 7.8463  an uptick of +15.1k. Most regions change little, Hudson most (+19k).

The delta map is attached as usual.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on July 18, 2016, 05:03:05 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.5370  -66.5  5.345257  -66.2 12.819805  -132.7 18.165062
Mon 2016.5397  -12.8  5.332489  +42.1 12.861951   +29.4 18.194440
Tue 2016.5425  -91.8  5.240649   +5.7 12.867640   -86.2 18.108289
Wed 2016.5452 -129.5  5.111185  -20.6 12.847038  -150.1 17.958223


Thanks, Wipneus. For those keeping score, 2016 SIA is now lower than the September minimums measured in 1979-1980, 1982-1983, 1986-1988, and 1996.
Title: Re: 2016 sea ice area and extent data
Post by: DoomInTheUK on July 18, 2016, 06:11:01 PM

Thanks, Wipneus. For those keeping score, 2016 SIA is now lower than the September minimums measured in 1979-1980, 1982-1983, 1986-1988, and 1996.

Thanks Jim - I love this time of year when you start ticking off the previous minima. It helps to keep the current state in perspective.
Title: Re: 2016 sea ice area and extent data
Post by: Neven on July 18, 2016, 06:38:20 PM
Neven, I think there's something wrong with those compactness graphs.  Calculating CAJAX, I obtain the same values as in your graph above, for all the years 2007-2015, but not for 2016.  It doesn't seem to be a leap-year problem, since I got the same values as you for 2012 and 2008 (but not for 2016).  I guess the problem is that the CT-area values for the year 2016 in your spreadsheet are not aligned correctly relative to the 2007-2015 data?

Steven, the latest SIA number as reported by Wipneus is 5111185 km2. I have entered this number for July 17th on my spreadsheet. You probably have it for July 16th, right?
Title: Re: 2016 sea ice area and extent data
Post by: Steven on July 18, 2016, 08:40:42 PM
Neven, I think there's something wrong with those compactness graphs.  Calculating CAJAX, I obtain the same values as in your graph above, for all the years 2007-2015, but not for 2016.  It doesn't seem to be a leap-year problem, since I got the same values as you for 2012 and 2008 (but not for 2016).  I guess the problem is that the CT-area values for the year 2016 in your spreadsheet are not aligned correctly relative to the 2007-2015 data?

Steven, the latest SIA number as reported by Wipneus is 5111185 km2. I have entered this number for July 17th on my spreadsheet. You probably have it for July 16th, right?

Neven,  Here is a piece of my CT-area spreadsheet (for the last 4 years), with the last column including the latest values reported by Wipneus:

Date            2012      2013      2014      2015      2016
0.5370         5.047     5.905     5.961     5.735     5.345
0.5397         5.037     5.784     5.864     5.616     5.332
0.5425         4.862     5.512     5.735     5.492     5.241
0.5452         4.800     5.351     5.606     5.399     5.111

Could you check whether your CT-area values are aligned in the same way?  I think your CT-area data in the last column (for 2016) are aligned in a different way compared to the other years.
Title: Re: 2016 sea ice area and extent data
Post by: Neven on July 18, 2016, 08:52:32 PM
That last row for date 0.5452 is July 18th in my spreadsheet, so the value for 2016 moves up one row and you get:

Date            2012      2013      2014      2015      2016
0.5370         5.047     5.905     5.961     5.735     5.332
0.5397         5.037     5.784     5.864     5.616     5.241
0.5425         4.862     5.512     5.735     5.492     5.111
0.5452         4.800     5.351     5.606     5.399   tomorrow

This has something to do with 0.000 not being the first day of the year, but the last day. Or something like that. I believe that as Wipneus is taking the latest NSIDC data to produce the CT SIA number, the 5.111 value must be for July 17th.

I'm so fed up with this! Every year!  ;) 

CT is no longer updated. I think I'm dropping it next year.
Title: Re: 2016 sea ice area and extent data
Post by: Steven on July 18, 2016, 09:59:40 PM
Neven,  according to Wipneus' comment today, the latest value (5,111,185 km2) is for CT-date 2016.5452, which corresponds to the last row in my table above.  I assume Wipneus is using the same conventions as in this file (http://arctic.atmos.uiuc.edu/cryosphere/timeseries.anom.1979-2008), from which I got the corresponding values for the other years:

Date              CT-area     
2015.5452    5.3986096
2014.5452    5.6062360
2013.5452    5.3513508
2012.5452    4.8000555
...

which correspond to the numbers on the last row of the table in my previous comment. 

I don't see any reason to move the values for 2016 in the table up by one row compared to the other years.  I agree that the exact day that corresponds to "date 0.5452" is a bit ambiguous  (it could be interpreted as 17 July, or 18 July or whatever), but as long as the same date 0.5452 is used for all the years there is no risk of confusion.  In any case I'm pretty sure that your CAJAX numbers for 2016 are not consistent with the other years (regardless of how leap years are treated).
Title: Re: 2016 sea ice area and extent data
Post by: Neven on July 18, 2016, 10:17:13 PM
I must have made a mistake when switching from the CT SIA data file to Wipneus' estimations. I'll try to remedy that, but it's a PITA.

edit: I'm checking my spreadsheet and 0.5452 for all other years is July 18th, but we can't know 0.5452 for this year yet as it's the 18th today. I've been over and over this with Wipneus (almost every year it seems), but I thought my spreadsheet was in agreement with his. Before, when CT was lagging, and Wipneus gave us the numbers two days ahead, the latest date would correspond with that of IJIS/JAXA.

And that's how it goes for me now too: JAXA SIE number for previous day comes in in the morning, Wipneus reports in the afternoon, et voilà. It would make sense if CT was lagging, not for it to be ahead one day.

Anyway, I'm confused. Wip, please advise, if you have the time.

And like I said, I'm dropping CT SIA next year, because of this annual waste of time and because the people behind CT seem to have switched to other stuff, which is fine, of course, CT being a legendary Arctic - and Antarctic - sea ice data provider.
Title: Re: 2016 sea ice area and extent data
Post by: Steven on July 18, 2016, 11:21:11 PM
edit: I'm checking my spreadsheet and 0.5452 for all other years is July 18th, but we can't know 0.5452 for this year yet as it's the 18th today.

Neven, here is the calculation that was posted by Wipneus exactly 1 year ago, on 18 July 2015:

http://forum.arctic-sea-ice.net/index.php/topic,1112.msg57098.html#msg57098 (http://forum.arctic-sea-ice.net/index.php/topic,1112.msg57098.html#msg57098)

The latest CT-value calculated in that comment was 5.398 million km2.  That is the value for date 2015.5452.

So, it seems that for every year (both leap years and non-leap years), the value for CT-date  0.5452 is the one that is calculated by Wipneus on 18 July, and hence corresponds to satellite observations that were made on 17 July.
Title: Re: 2016 sea ice area and extent data
Post by: Bill Fothergill on July 19, 2016, 01:03:59 AM
@ Steven & Neven    RE: CT date formats

A couple of years ago, I exchanged emails with Bill Walsh of the Polar Research team at UIUC. He indeed confirmed that, using their numbering conventions, the date stamp for, say, 2016.0000 would relate to the 31st December 2015.

I don't remember the exact reason(s), but it was something of a historic "accident". In the dim and distant past, that was simply the way some early coding had been set up - I think it was then subsequently felt that introducing a change could cause more confusion than it would eliminate.

(My email system is playing up at the moment, otherwise I would cut&paste the words Bill Walsh actually used - rather than employing my "less than 100% reliable memory".)

As regards yyyy.5452, I've only imported the CT data from 2000 onward, and that date stamp certainly relates to July 18 each time. (Which is Day 200 for leap years, and Day 199 the rest of the time.)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 19, 2016, 10:04:20 AM
@ Steven & Neven    RE: CT date formats

As regards yyyy.5452, I've only imported the CT data from 2000 onward, and that date stamp certainly relates to July 18 each time. (Which is Day 200 for leap years, and Day 199 the rest of the time.)

So far so good. July 18 would be the tag that CT uses and there would be no reason to doubt that. Unless of course you try to replicate it like I have been doing for a couple of years with increasing accuracy. Then you find, as I did, that that requires sea ice concentration data from NSIDC that was tagged 17th of July.

It is really up to you, 17th or 18th. I am trying to be safe reporting 2016.5452
Title: Re: 2016 sea ice area and extent data
Post by: Neven on July 19, 2016, 11:30:59 AM
So, basically, if I get this year to be in line with all the other years in my spreadsheet, and then transfer that to my CAJAX sheet, CT will basically be one day ahead of JAXA?
Title: Re: 2016 sea ice area and extent data
Post by: Tealight on July 19, 2016, 12:34:17 PM
I had the same problem with CT area in my calculations. Thankfully Wipneus provides 'NSIDC Area' on his website which has the same date as NSIDC extent. lt also excludes lake ice and uses correct grid cell sizes. My forecast model improved by 10% thanks to him.

If CT won't switch to the new F18 data this year than maybe we should switch completly to 'NSIDC Area'.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 19, 2016, 12:53:30 PM
So, basically, if I get this year to be in line with all the other years in my spreadsheet, and then transfer that to my CAJAX sheet, CT will basically be one day ahead of JAXA?

If CT reports data from the 17th as the 18th, I would call that "be one day behind".
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 19, 2016, 04:36:44 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:
day  CT-date       NH               SH                Global
Mon 2016.5397  -12.8  5.332489  +42.1 12.861951   +29.4 18.194440
Tue 2016.5425  -91.8  5.240649   +5.7 12.867640   -86.2 18.108289
Wed 2016.5452 -129.8  5.110889  -20.5 12.847105  -150.3 17.957994
Thu 2016.5479  -83.6  5.027240  -14.1 12.833030   -97.7 17.860270


Serious declines in CAB (-27k), ESS (-24k) and Laptev (-21k).

Shadow NSIDC is now 7.7462 dropping -100.2k. The way to the bottom is led todayby ESS (-57k) and Baffin (-35k).

Of course a delta map is attached to the daily shadow report.
Title: Re: 2016 sea ice area and extent data
Post by: Neven on July 20, 2016, 12:21:29 AM
Okay, I've slept only 3 hours last night, and been working and designing some stuff since 6 AM. And now I've spent a whole hour to see where the mistake is.

Neven,  Here is a piece of my CT-area spreadsheet (for the last 4 years), with the last column including the latest values reported by Wipneus:

Date            2012      2013      2014      2015      2016
0.5370         5.047     5.905     5.961     5.735     5.345
0.5397         5.037     5.784     5.864     5.616     5.332
0.5425         4.862     5.512     5.735     5.492     5.241
0.5452         4.800     5.351     5.606     5.399     5.111

Could you check whether your CT-area values are aligned in the same way?  I think your CT-area data in the last column (for 2016) are aligned in a different way compared to the other years.

Steven, I've just checked the CT SIA data file and the numbers correspond with the data up to 2015. However, if I look at Wipneus' file, I get this:

Date        Steven    Wip
0.5370         5.345     5.332
0.5397         5.332     5.241     
0.5425         5.241     5.111     
0.5452         5.111     5.027     

Could you please check your spreadsheet and compare to Wipneus' AreaCalculatedLikeCryosphereToday.txt file?
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on July 20, 2016, 08:44:00 AM
It seems that the ice dispersion due to persistent lows over the Arctic is finally taking a toll on the Central Arctic Basin.

Over the past couple of days, Sea Ice Area in the CAB has taken an unprecedented nose dive on Wipneus' AMSR2 graph :

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi1272.photobucket.com%2Falbums%2Fy396%2FRobDekker%2FScreen%2520Shot%25202016-07-19%2520at%252011.25.24%2520PM_zpst9pkplki.png&hash=7bfd4680f14554070581ac59b5d19d1b)

When 'area' drops, 'extent' drops are typically close to follow.
So expect some dramatic drops in the major indexes in the next couple of days.
Title: Re: 2016 sea ice area and extent data
Post by: Pmt111500 on July 20, 2016, 09:34:02 AM
Quote
This has something to do with 0.000 not being the first day of the year, but the last day. Or something like that. I believe that as Wipneus is taking the latest NSIDC data to produce the CT SIA number, the 5.111 value must be for July 17th.

Ah, there it is again. This explained the day or two error between my and some other' calculations. Too bad the CT SIA old values from 1979-2000? are cannot be scientifically correlated to the other area values. I've almost stopped following the progression of the melt this year, but I guess I need to come back to check the situation in nov-dec.
Title: Re: 2016 sea ice area and extent data
Post by: dnem on July 20, 2016, 01:07:58 PM
Wipneus's CAB graph posted above strikes me as the most relevant and important graph with respect to where this season might be headed that I've seen so far this year.  The drop is "unprecedented" more in how early it is than how steep or long.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on July 20, 2016, 02:42:28 PM
Cyrosphere Today has *always* had a bit of trouble with dates, as we've seen and discussed time and again.

For starters, they've handled leap years/leap days in an inconsistent fashion:


On top of that, there's the "which day is the actual start of the year?" question. Obviously, some use Day 0.0000 as the December 31, which doesn't really make a lot of sense, given that, for instance, December 31 this year would be "2017.0000". Others--such as myself--consider the day as belonging to the year represented by the four digits to the left of the decimal.

Meh.

The thing for me has always been consistency. That is, we're not so much concerned with daily values as we are about trends; it's less important to know on what calendar day the annual minimum fell than it is to know just what the minimum was.

Having said all that: given that CT's SIA file has shown the same value for 74 consecutive days now, and given the vagaries of area measurements, I too would be happy to drop it as a metric here. It's simply too much work to illustrate a sometimes nearly valueless number...
Title: Re: 2016 sea ice area and extent data
Post by: Steven on July 20, 2016, 03:07:54 PM
Steven, I've just checked the CT SIA data file and the numbers correspond with the data up to 2015. However, if I look at Wipneus' file, I get this:

Date        Steven    Wip
0.5370         5.345     5.332
0.5397         5.332     5.241     
0.5425         5.241     5.111     
0.5452         5.111     5.027     

Could you please check your spreadsheet and compare to Wipneus' AreaCalculatedLikeCryosphereToday.txt file?

Neven, you're not aligning the "Wip" values correctly.  Compare with the values in this comment by Wipneus upthread:

    CT-date              NH         ...                     
    2016.5370  ...  5.345257  ...
    2016.5397  ...  5.332489  ...
    2016.5425  ...  5.240649   
    2016.5452  ...  5.111185 
Title: Re: 2016 sea ice area and extent data
Post by: Neven on July 20, 2016, 03:48:24 PM
We're getting to the crux of the matter.

On July 18th and 19th Wipneus wrote this:

Quote
2016.5452 - 5.111185

But in the AreaCalculatedLikeCryosphereToday.txt data file it says (see attachment):

Quote
2016.5452 - 5.027240

So, what is it? I couldn't be more confused.
Title: Re: 2016 sea ice area and extent data
Post by: JimD on July 20, 2016, 04:13:23 PM
I envision this discussion in a dank dark tower in the middle ages.  Several monks from different monastery's are huddles around a table with BIG magnifying glasses and examining the head of a pin.  One is saying that angel is in a different place on the pin than last year and another is saying it is not.  The third monk is saying no you both are wrong that is the identical twin angel left over from the last leap year and it should have been removed and replaced with a regular angel.  Another monk is insisting that what is important is not where they are standing on the head of the pin but how many there are.  Being it is like ground hog day they go through this every year even though the difference in how many or what kind of angels are on the head of the pin from day to day has no relevance to speak of.   8)
Title: Re: 2016 sea ice area and extent data
Post by: Neven on July 20, 2016, 04:20:13 PM
And on top of that, the pin is crooked!  ;)
Title: Re: 2016 sea ice area and extent data
Post by: Dundee on July 20, 2016, 04:42:00 PM
Much worse than that - the old pin is broken, and we have to spend MONTHS proving to ourselves the new pin is just the same. Or it is not. Or it is, but only below 50ghz.
Title: Re: 2016 sea ice area and extent data
Post by: Dundee on July 20, 2016, 05:32:57 PM
On a more serious note, I am a beginner at this corner of analysis, but it took maybe thirty minutes to determine that leap year is a problem and a few days to determine that it is, more properly, a major pain in the rump (I am working with linear regressions day-wise, and they fall apart if the days do not match up).

Restating dates as fractional years is not bad, but pinning them to December 31st is. For my work, I've used whole number days, but pinned them to the date and time of the winter solstice. This leaves a dislocation when the equinox jumps between, say 1002 hours to 1359 hours (the former rounding to the previous day and the latter to the next) and it also leaves a leap day equivalent the day before the solstice. In practical terms, little is happening that time of the year ice-wise, and locking most of the year to the solar calendar improves the quality of regressions through the period of active analysis (at the cost of what ends up being 3-14 days of disturbed numbers in late December).

Below is a chart of the behavior of the summer solstice (shamelessly lifted from Wikipedia). By restating my data, I still have the underlying four year cycle, but have taken out the long term drift. As an aside, we have the Gregorian Calendar to thank for the fact there was no hundred year reset, which from today's perspective would have neatly divided the satellite record into nearly even halves.

I could use a precise annual fractional date (avoiding the rounding skip when the solstice jumps between morning and afternoon) but convinced myself there would be no point - this would add only false precision. The daily figures (from whatever source) are not based on a daily snapshot at 0000 or 1200 hours UT, but are rather based on whatever and whenever the satellite(s) served up throughout that day, based on their orbital mechanics and other conditions. To be anything like rigorous, you'd have to also regroup the orbit by orbit data streams to solar days rather than calendar days (and please, don't even talk about sidereal days - we - I'm pretty sure - don't care about them in this context, despite their role in orbital mechanics).

The real lesson to all of this is exactly as JimD stated above - if you are hanging on day to day numbers, be it daily changes or year to year comparisons, what is catching your eye is almost certainly more noise than signal. A good example is "do the peaks occur later (or earlier) now" - they may or may not, but unless all the underlying analysis effectively addresses the difference between the solar and calendar years, it is likely to misstate the picture, because any actual change is on a comparable scale to the equinox progression over the years of satellite record.
Title: Re: 2016 sea ice area and extent data
Post by: Nick_Naylor on July 20, 2016, 06:09:05 PM
Even if you could synchronize the dates exactly, getting too hung up on daily values between years is giving too much credit to the noise vs. the signal.

Similarly, worrying about whether any particular measurement is a record vs. 2nd or 3rd place is human nature, but kind of superficial, especially when the other years are close to each other. Not that I'm immune to such silliness . . .  ::)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 20, 2016, 06:13:26 PM
We're getting to the crux of the matter.

On July 18th and 19th Wipneus wrote this:

Quote
2016.5452 - 5.111185

But in the AreaCalculatedLikeCryosphereToday.txt data file it says (see attachment):

Quote
2016.5452 - 5.027240

So, what is it? I couldn't be more confused.

Ohh, that is obviously incorrect. I will let you know when fixed, checked and double checked.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 20, 2016, 06:22:45 PM
In the mean time here is the report, with suspicious dates.

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

day  CT-date       NH               SH                Global
Tue 2016.5425  -91.8  5.240649   +5.7 12.867640   -86.2 18.108289
Wed 2016.5452 -129.8  5.110889  -20.5 12.847105  -150.3 17.957994
Thu 2016.5479  -83.8  5.027092  -14.1 12.833030   -97.9 17.860122
Fri 2016.5507   -7.4  5.019653  -68.8 12.764215   -76.3 17.783868

Only regional area increase worth mentioning is CAB: +24k.

Shadow NSIDC extent is 7.6691 dropping  -77.1k. ESS (-32k) and Hudson (-24k) dropped most. Baffin increased by +35k, contrast with UH AMSR2 results that indicated a large drop in that region.

As always, the delta map is there.
Title: Re: 2016 sea ice area and extent data
Post by: Neven on July 20, 2016, 06:30:00 PM
Ohh, that is obviously incorrect. I will let you know when fixed, checked and double checked.

Thanks for checking, Wipneus. I'm sorry the old CT-beast bites us yet again.

I think your file is correct, as the date for the 2016 values correspond with those of previous years. So maybe you jumped a date when reporting here. That's usually how my spreadsheet gets screwed up (not entering one value and then just trudging on).
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 21, 2016, 04:32:56 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.5452 -129.8  5.110889  -20.5 12.847105  -150.3 17.957994
Thu 2016.5479  -83.8  5.027092  -14.1 12.833030   -97.9 17.860122
Fri 2016.5507   -7.2  5.019887  -68.6 12.764399   -75.8 17.784286
Sat 2016.5534  -79.7  4.940148 +123.2 12.887570   +43.4 17.827718


With biggest regional area declines in the CAB (-32k) and CAA (-23k).

Shadow NSIDC extent is now 7.5276 dropping -141.5k. Biggest declines in ESS (-37k), CAA (-33k), Baffin (-27k) and Kara (-25k). Greenland Sea provided the uptick (+19k).

Concluding as ever with the attached daily delta map.

Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on July 21, 2016, 04:47:39 PM
FWIW, as of tomorrow, 2016 SIA will be lower than the annual minimums recorded in the following years:

1979-1983
1985-1988
1992
1996
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on July 21, 2016, 05:27:35 PM
Despite the big extent drops in the last 2 days, both the single day and now 5 day NSIDC extent are up to 4th lowest on record.

With the 5 day average, we are now approaching the minimum value set in 1980. Another 3-4 days and we should drop the 179k required.

Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on July 22, 2016, 04:47:01 PM
A relatively small drop today of 63k on the NSIDC extent. Still 4th lowest, and now just 40k below 2013.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 22, 2016, 06:03:58 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.5479  -83.8  5.027092  -14.1 12.833030   -97.9 17.860122
Fri 2016.5507   -7.2  5.019887  -68.6 12.764399   -75.8 17.784286
Sat 2016.5534  -79.8  4.940048 +123.2 12.887609   +43.4 17.827657
Sun 2016.5562 -136.3  4.803748  +27.8 12.915445  -108.5 17.719193


Regional CAB dropped most(-56k), with ESS (-19k) second.

Shadow NSIDC extent is now 7.4648 dropping  -62.8k. Baffin dropped -33k, ESS -18k.

The daily delta map is attached as usual.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 23, 2016, 05:46:22 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:
day  CT-date       NH               SH                Global
Fri 2016.5507   -7.2  5.019887  -68.6 12.764399   -75.8 17.784286
Sat 2016.5534  -79.8  4.940048 +123.2 12.887609   +43.4 17.827657
Sun 2016.5562 -136.3  4.803723  +27.8 12.915419  -108.5 17.719142
Mon 2016.5589  -42.2  4.761475 +115.7 13.031137   +73.5 17.792612


Laptev shows the biggest drop (-37k), while CAB increases by +25k.

Shadow NSIDC extent is now 7.3859  dropping -79.0k. Most of that is in the Beaufort (-37k), ESS is second with -19k.

The delta map is attached as always.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on July 24, 2016, 04:11:59 PM
Update for the week to July 23rd

The current 5 day trailing average is on 7,468,000km2 while the 1 day extent is at 7,293,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,569,000km2, a decrease from -1,760,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at +198,000km2, an increase from +33,000km2 last week. We're currently 4th lowest on record, down from 3rd last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FEuPrRYX.png&hash=fbbd2a3328950b3d760cac83bce271d6)

The average daily change over the last 7 days was -62.0k/day, compared to the long term average of -89.4k/day, and the 07, 11 and 12 average of -85.6k/day.
The average long term change over the next week is -86.1k/day, with the 07, 11, and 12 average being -81.5k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FJFvz8WA.png&hash=d8d764308d6275b5e0775e9af1d54a58)

The extent loss so far this July is the 17th smallest on record. To achieve the largest monthly loss, a drop of at least 188.9k/day is required (requiring ~222.6k/day with with single day values), while the smallest loss requires a drop of less than 0.6k/day (~28.4k/day increase with single day values) and an average loss requires a drop of 73.0k/day (~81.5k/day with single day values).

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FuGwVzsv.png&hash=b3c63460d0909464650375a69ce648f0)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on July 24, 2016, 04:17:05 PM
The 5 day average NSIDC extent has dropped below the first previous minimum set in 1980. We're now also within 500k of 6 other years, 1982, 83, 86, 88, 92 and 96.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FQmcPbxO.png&hash=dbc994ed4d794201295996596fcfd578)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 24, 2016, 05:51:13 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.5534  -79.8  4.940048 +123.2 12.887609   +43.4 17.827657
Sun 2016.5562 -136.3  4.803723  +27.8 12.915419  -108.5 17.719142
Mon 2016.5589  -42.1  4.761607 +115.6 13.030979   +73.4 17.792586
Tue 2016.5616   -9.6  4.751969 +137.0 13.168003  +127.4 17.919972



Very quiet regionally, CAB changed most an increase of +16k.

Shadow NSIDC extent is 7.2931 dropping -92.8k. ESS dropped -48k, Hudson -20k. Kara increased +19k.

Today´s delta map is attached .

[EDIT: fixed the NSIDC extent value, thanks BFTV]
Title: Re: 2016 sea ice area and extent data
Post by: Steven on July 24, 2016, 07:34:54 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

2016.5616   ... 4.751969

Now in 4th place.

Date                  CT-area
2012.5616        4.425 million km2
2011.5616        4.554
2007.5616        4.680
2016.5616      4.752
2013.5616        4.864
       ...                  ...

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FPfqMvgZ.png&hash=4f45fb92c974fc464254744326d7f820)
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on July 25, 2016, 12:35:29 PM
ADS-NIPR Extent:
6,990,510 km2 (24 July)
Down 6,951,997 km2 (49.86%) from 2016 maximum of 13,942,507 km2 on 29 February.
3,813,055 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 77,463 km2 (-1.1%) from previous day.
Down 464,446 km2  (-6.23%) over past seven days (daily average: -66,349 km2).
Down 1,983,198 km2  (-16.21%) for July (daily average: -82,633 km2).
887,147 km2 below 2000s average for this date.
20,029 km2 below 2010s average for this date.
126,567 km2 below 2015 value for this date.
280,016 km2 above 2012 value for this date.
1st lowest year-to-date (01 January - 24 July) average.
1st lowest July to-date average.
4th lowest value for the date.
128 days this year (62.44% year-to-date) have recorded the lowest daily extent.
35 days (17.07%) have recorded the second lowest.
24 days (11.71%) have recorded the third lowest.
187 days in total (91.22%) have been among the lowest three on record.


CT Area:
4,751,969 km2 (25 July [Day 0.5616])
Down 8,169,389 km2 (63.22%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
2,517,960 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 9,638 km2 (-.2%) from previous day.
Down 488,680 km2 (-9.56%) over past seven days (daily average: -69,811 km2).
Down 2,342,299 km2 (-21.03%) for July (daily average: -93,692 km2).
801,202 km2 below 2000s average for this date.
79,029 km2 below 2010s average for this date.
190,334 km2 below 2015 value for this date.
326,777 km2 above 2012 value for this date.
4th lowest value for the date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' "shadow area" numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 25, 2016, 04:43:07 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.5562 -136.3  4.803723  +27.8 12.915419  -108.5 17.719142
Mon 2016.5589  -42.1  4.761607 +115.6 13.030979   +73.4 17.792586
Tue 2016.5616   -9.8  4.751839 +137.0 13.167949  +127.2 17.919788
Wed 2016.5644  -84.5  4.667375  +81.5 13.249405    -3.0 17.916780


ESS again dropped most :-35k.

NSIDC extent is now 7.2554 down -37.6k. ESS (again) dropped most: -30k.

The daily delta map is attached as expected.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on July 25, 2016, 04:45:55 PM
Latest situation with regard to previous NSIDC extent minima (using the 5 day average)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FGqL471h.png&hash=5d3e6f600647a63952e822ee808df6d7)

Diff...........No of Years.....Percentage
Below 0..........1................3%
0-100k...........0................0%
100-250k........5...............14%
250-500k........6...............16%
500-1000k......4................11%
>1000k.........21...............57%
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 26, 2016, 05:15:58 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Mon 2016.5589  -42.1  4.761607 +115.6 13.030979   +73.4 17.792586
Tue 2016.5616   -9.8  4.751839 +137.0 13.167949  +127.2 17.919788
Wed 2016.5644  -84.3  4.667566  +81.4 13.249363    -2.9 17.916929
Thu 2016.5671  -46.3  4.621297   +7.4 13.256752   -38.9 17.878049


Regionally ESS continues to decline (-24k), Hudson -15k while the CAB increased by +19k.

Shadow NSIDC extent is now 7.2033 dropping -52.2k. Hudson sold for -23k less, Beaufort -19k and Kara -15k.

Concludes with the attached delta map.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 27, 2016, 04:52:41 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Tue 2016.5616   -9.8  4.751839 +137.0 13.167949  +127.2 17.919788
Wed 2016.5644  -84.3  4.667566  +81.4 13.249363    -2.9 17.916929
Thu 2016.5671  -46.3  4.621301   +7.4 13.256794   -38.8 17.878095
Fri 2016.5699  -53.0  4.568267  +54.4 13.311227    +1.4 17.879494


No big regional changes, except the CAB: -34k.

Shadow NSIDC extent is 7.1714 dropping  -31.9k. Baffin coughed up -31k, Laptev was second at -19k.

The daily delta map is attached as always.
Title: Re: 2016 sea ice area and extent data
Post by: epiphyte on July 27, 2016, 06:28:06 PM
Wow. Looks like they woke up in Sandusky Ohio this morning not only hot and bothered in the 90s, but also unexpectedly icebound!
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 28, 2016, 06:14:32 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.5644  -84.3  4.667566  +81.4 13.249363    -2.9 17.916929
Thu 2016.5671  -46.3  4.621301   +7.4 13.256794   -38.8 17.878095
Fri 2016.5699  -52.9  4.568436  +54.4 13.311186    +1.5 17.879622
Sat 2016.5726  -64.4  4.504044  -52.5 13.258720  -116.9 17.762764


Like yesterday is is only the CAB that is moving: -41k this time.

Shadow NSIDC extent is now 7.1386 dropping -32.8k. Kara had an uptick of +23k. Other regions were slow, Beaufort most with -13k.

The daily delta map is where you can expect it.
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on July 28, 2016, 10:07:44 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.5644  -84.3  4.667566  +81.4 13.249363    -2.9 17.916929
Thu 2016.5671  -46.3  4.621301   +7.4 13.256794   -38.8 17.878095
Fri 2016.5699  -52.9  4.568436  +54.4 13.311186    +1.5 17.879622
Sat 2016.5726  -64.4  4.504044  -52.5 13.258720  -116.9 17.762764


Like yesterday is is only the CAB that is moving: -41k this time.

Shadow NSIDC extent is now 7.1386 dropping -32.8k. Kara had an uptick of +23k. Other regions were slow, Beaufort most with -13k.

The daily delta map is where you can expect it.
<snippage> moved to a better thread for the discussion.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on July 29, 2016, 12:52:34 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.5644  -84.3  4.667566  +81.4 13.249363    -2.9 17.916929
Thu 2016.5671  -46.3  4.621301   +7.4 13.256794   -38.8 17.878095
Fri 2016.5699  -52.9  4.568436  +54.4 13.311186    +1.5 17.879622
Sat 2016.5726  -64.4  4.504044  -52.5 13.258720  -116.9 17.762764



2016 has one more day to gain ground on 2012, with the latter losing just 1k of area on 0.5753. Then the GAC kicked in that year, stripping away more than a million square kilometers of ice over a 10-day period. It's highly doubtful we'll see any such thing this year, and because of that, it's looking more and more as though 2016 will bottom out between 3.4M and 3.6M --that is, somewhere around or just above the average of the last ten years.

FWIW, 2016 SIA is now lower than the annual minima recorded from 1979-1990, 1992, 1994, 1996-1997, and 2001.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on July 29, 2016, 03:56:32 PM
Huge drop on the single day NSIDC extent, down 230k, but still 4th lowest on record.

Using the 5 day trailing average, we have now dropped below the minima of 6 of the 37 previous years.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FLMATI6g.png&hash=d52f409e5c942de240341d5d5004b50d)

Below are the stats with regard to all previous minima and current 5 day extent.

Diff..........No of Years.....Percentage
Below 0..........6...............16.2%
0-100k...........1.................2.7%
100-250k........5...............13.5%
250-500k........0.................0.0%
500-1000k......7................18.9%
>1000k.........18................48.6%
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 29, 2016, 04:18:14 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.5671  -46.3  4.621301   +7.4 13.256794   -38.8 17.878095
Fri 2016.5699  -52.9  4.568436  +54.4 13.311186    +1.5 17.879622
Sat 2016.5726  -64.8  4.503638  -52.6 13.258609  -117.4 17.762247
Sun 2016.5753 -182.0  4.321657 +157.2 13.415760   -24.8 17.737417



A century for area of the CAB: -112k, Beaufort second (-31k) and even CAA worth mentioning (-19k).

Shadow NSIDC extent is now 6.9094 dropping -229.2k. Many regions did their best: Beaufort (-84k), Kara (-33k), CAA (-27k), Laptev (-21k) and ESS (-20k).

Today's delta map is filled with reds and pinks.
Title: Re: 2016 sea ice area and extent data
Post by: Shared Humanity on July 29, 2016, 10:42:46 PM
What worries me are the blue areas along the Atlantic side. The ice is beginning to migrate towards the Barents. It won't last long as it moves into these very warm waters.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on July 30, 2016, 02:28:09 PM
ADS-NIPR Extent:
6,622,391 km2 (29 July)
Down 7,320,116 km2 (52.5%) from 2016 maximum of 13,942,507 km2 on 29 February.
3,444,936 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 62,949 km2 (-.94%) from previous day.
Down 505,285 km2  (-7.09%) over past seven days (daily average: -72,184 km2).
Down 2,351,317 km2  (-19.22%) for July (daily average: -81,080 km2).
848,518 km2 below 2000s average for this date.
20,395 km2 below 2010s average for this date.
107,661 km2 below 2015 value for this date.
419,358 km2 above 2012 value for this date.
Lowest year-to-date (01 January - 29 July) average.
3rd lowest July to-date average.
4th lowest value for the date.
128 days this year (60.95% year-to-date) have recorded the lowest daily extent.
35 days (16.67%) have recorded the second lowest.
24 days (11.43%) have recorded the third lowest.
187 days in total (89.05%) have been among the lowest three on record.


CT Area:
4,321,657 km2 (30 July [Day 0.5753])
Down 8,599,701 km2 (66.55%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
2,087,648 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 181,981 km2 (-4.04%) from previous day.
Down 482,066 km2 (-10.12%) over past seven days (daily average: -68,867 km2).
Down 2,772,611 km2 (-24.89%) for July (daily average: -92,420 km2).
965,307 km2 below 2000s average for this date.
238,082 km2 below 2010s average for this date.
210,109 km2 below 2015 value for this date.
85,790 km2 above 2012 value for this date.
3rd lowest value for the date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' "shadow" area numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!


Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 30, 2016, 04:43:52 PM

day  CT-date       NH               SH                Global
Fri 2016.5699  -52.9  4.568436  +54.4 13.311186    +1.5 17.879622
Sat 2016.5726  -64.8  4.503638  -52.6 13.258609  -117.4 17.762247
Sun 2016.5753 -182.3  4.321316 +157.4 13.415964   -25.0 17.737280
Mon 2016.5781  -40.7  4.280588 +156.8 13.572807  +116.1 17.853395



Again it the CAB at its own that does the lifting: -45k.

Shadow NSIDC extent is 6.9211 an increase of +11.7k. Little changes regionally, Hudson most with +13k.

The delta map is attached as always.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on July 31, 2016, 04:20:35 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.5726  -64.8  4.503638  -52.6 13.258609  -117.4 17.762247
Sun 2016.5753 -182.3  4.321316 +157.4 13.415964   -25.0 17.737280
Mon 2016.5781  -40.1  4.281226 +156.9 13.572847  +116.8 17.854073
Tue 2016.5808 -143.9  4.137335 +187.0 13.759852   +43.1 17.897187



Something big just dropped: Laptev (-67k) , CAB (-49k) and CAA (-23k).

Shadow NSIDC extent is now 6.7194 dropping a big -201.7. It is not the first of the month (that won't be for two days) but Laptev -135k. CAA (-38k) and CAB (-19k) follow behind. Beaufort recovers with a +25k uptick.

The attached delta map shows the damage done.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on July 31, 2016, 04:38:28 PM
Update for the week to July 30th

The current 5 day trailing average is on 6,972,000km2 while the 1 day extent is at 6,719,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,462,000km2, a decrease from -1,569,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at +272,000km2, an increase from +198,000km2 last week. We're currently 4th lowest on record, same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fsg0J9PA.png&hash=50a1855e2d7b54e744177db364544b1a)

The average daily change over the last 7 days was -70.9k/day, compared to the long term average of -86.1k/day, and the 07, 11 and 12 average of -81.5k/day.
The average long term change over the next week is -79.4k/day, with the 07, 11, and 12 average being -77.5k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FRK5Kk8d.png&hash=2bd4e65a8528ba30ec676464f78c5cfd)

The extent loss so far this July is the 17th smallest on record. To achieve the largest monthly loss, a drop of at least 1,019.4k/day is required (requiring ~4,619k/day with with single day values), while the smallest loss requires an increase of at least 491.4k/day (~2,199k/dayincrease with single day values) and an average loss requires a drop of 164.0k/day (~369k/day with single day values).

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FZV52V92.png&hash=056b4a9bf973cfdc681b8f39f123fc8e)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on July 31, 2016, 04:50:10 PM
Using the 5 day average, we've now dropped below 7/37 previous minima, and we're within 500k of another 12.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FQiqrvEm.png&hash=a3eaa4191da05af2a004cd9808e4137c)

Some stats on the difference between current extent and previous minima

Diff.............No of Years....Percentage
Below 0.............7.............18.9%
0-100k..............5.............13.5%
100-250k...........0.............0.0%
250-500k...........3.............8.1%
500-1000k.........8.............21.6%
>1000k.............14............37.8%
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on July 31, 2016, 05:29:49 PM
Wipneus's "shadow" area numbers show that 2016 SIA has dropped below the annual minima recorded in every year prior to 2004, with the exception of 2002. Three more years should be beaten in the next few days--2002, 2005, and 2006--and then there's a substantial gap before the next years is past (2013).
Title: Re: 2016 sea ice area and extent data
Post by: Steven on July 31, 2016, 08:04:37 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

2016.5808  ...  4.137335

Currently 2nd lowest (behind 2012):

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FJVRgZ4p.png&hash=c83572136a9ce306910bb655ca383154)
Title: Re: 2016 sea ice area and extent data
Post by: Michael Hauber on August 01, 2016, 06:19:35 AM
ADS daily change:  -96228
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on August 01, 2016, 10:17:14 AM
Back in second place huh ?
Title: Re: 2016 sea ice area and extent data
Post by: Shared Humanity on August 01, 2016, 02:51:38 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

2016.5808  ...  4.137335

Currently 2nd lowest (behind 2012):

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FJVRgZ4p.png&hash=c83572136a9ce306910bb655ca383154)

With SIA 2nd lowest and SIE not dropping as quickly, the ice is spread out more than in years past. This can't be good news for the remainder of the melt season.
Title: Re: 2016 sea ice area and extent data
Post by: Gray-Wolf on August 01, 2016, 03:05:16 PM
This is why I'm now seeing the late winter Fragmentation events as a new direction as the basin moves toward a seasonal routine? 3 year old ice has been through 3 cycles with old fracture line criss crossing newer ones. Warm water/weather does for the 'glue' holding floes together and leaves us with floes so small the heat enters through top, base and sides.

We are left seeing similar levels of energy doing far more damage to the ice volume than in past years?

I'm still thinking we might go low but it will be the last couple of weeks of melt season that will reveal this as large ares of fragmented ice, that would have survived other seasons due to being part of big floes, blink out?

In the future I imagine we could look at any sized floe and know how much energy will be needed to see it melt? Such calcs have to involve it's fragmentation potential though?

As it is the 'leftover ice' will be so thin that , by winters end, we will still be seeing floes in the range of FY ice? That will mean plenty of break ups over the winter and just exacerbate next seasons woes........... and remember next year is the earliest possible return of the perfect melt storm synoptic ( we'll know pretty quickly if it isn't!)
Title: Re: 2016 sea ice area and extent data
Post by: Bill Fothergill on August 01, 2016, 03:25:51 PM
...
leaves us with floes so small the heat enters through top, base and sides.
...


Exactly. Consider the hypothetical case of a cube of ice that is (say) one metre along each edge. The volume would obviously be one cubic metre, and its surface area would be 6 sq metres.

Now imagine if this was somehow fractured into 8 identical smaller cubes, such that each edge was only 0.5 metres. The volume would be unchanged, but the total surface area would double to 12 sq metres. With uneven fracturing, the ratio between surface area and volume would rise much faster.

As the rate of energy transfer into the ice is a function of surface area...   Well, I don't think it needs to be spelled out.
Title: Re: 2016 sea ice area and extent data
Post by: Neven on August 01, 2016, 04:09:20 PM
ADS daily change:  -96228

In the latest ASI update I wrote: If it now somehow manages to end the month between 2011 and 2015, there's still room for August weather to keep the race exciting.

Well, JAXA SIE managed to do just that:
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 01, 2016, 04:52:33 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.5753 -182.3  4.321316 +157.4 13.415964   -25.0 17.737280
Mon 2016.5781  -40.1  4.281226 +156.9 13.572847  +116.8 17.854073
Tue 2016.5808 -144.1  4.137164 +187.3 13.760145   +43.2 17.897309
Wed 2016.5836  -97.3  4.039888 -115.2 13.644908  -212.5 17.684796


Three regions: ESS (-27k), CAA (-26k) and CAB (-20k) are the main contributors.

Shadow NSIDC extent is now 6.6645 dropping  -54.8k. Laptev had a big rebound: +74k, as long as there is a lot of ice hoovering around 15% concentration such swings can be expected. There are also big declines: CAA (-55k), ESS (-33k) , Hudson (-24k) and CAB (-18k).

The delta map has a colorful way of telling the story.
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on August 01, 2016, 05:33:02 PM
...
leaves us with floes so small the heat enters through top, base and sides.
...


Exactly. Consider the hypothetical case of a cube of ice that is (say) one metre along each edge. The volume would obviously be one cubic metre, and its surface area would be 6 sq metres.

Now imagine if this was somehow fractured into 8 identical smaller cubes, such that each edge was only 0.5 metres. The volume would be unchanged, but the total surface area would double to 12 sq metres. With uneven fracturing, the ratio between surface area and volume would rise much faster.

As the rate of energy transfer into the ice is a function of surface area...   Well, I don't think it needs to be spelled out.
For what it's worth, side melt doesn't contribute significantly until your floe size gets under 150M or so in diameter.
Title: Re: 2016 sea ice area and extent data
Post by: Bill Fothergill on August 02, 2016, 01:10:34 AM

For what it's worth, side melt doesn't contribute significantly until your floe size gets under 150M or so in diameter.

I actually think the floe fracturing needs to take place on a considerably smaller scale than 150 metres for the effect I was describing to become manifest. (In my very hypothetical example, I started with a unit cube.)

The total surface area of circular floe with a diameter of 150 metres and a thickness of 1 metre would be just under 36 thousand sq metres. The effect of a full-depth vertical fracture line running edge-to-edge straight through the centre would only increase the total surface area by a little under 1%.

However, a similar fracture through a second circular floe of the same thickness, but with a 15 metre diameter would result in a ~7% overall increase in surface area. For a 5 metre diameter floe, the increase rises to 18%. It is when the horizontal scale approaches the thickness scale that the effect really kicks into gear.

When we get real "slushy" ice, the scaling should be such that surface area increase becomes a significant contributory factor to the enthalpy increase of the ice mass.

For floes where the areal dimensions are still significantly larger than the thickness, I would expect effects such as abrasion along fractures to greatly outweigh side melt.
Title: Re: 2016 sea ice area and extent data
Post by: Michael Hauber on August 02, 2016, 02:55:51 AM
This study (http://onlinelibrary.wiley.com/doi/10.1002/grl.50190/full) claimed that without the GAC 2012 minimum would have been only 150k higher.  The PIOMAS model for no GAC falls about 450k behind in late August, but catches up again to only be 150k behind at minimum.  I think in part the GAC just sped up the melting of the vulnerable ice that was doomed to melt anyway.  And in part the melting was sped up by mixing, at the cost of reduced ocean heat available for later in the season.

It is interesting to look at what that study considers the 'no GAC' case.  They take the same weather conditions during the GAC but halve the wind speeds.  So cool and cloudy, but without the severe winds.  Presumably if the GAC was replaced by warmer and sunnier conditions similar to what is currently forecast than the minimum for the No GAC case  in 2012 would have been reduced further, perhaps beyond what occurred with the GAC.
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on August 02, 2016, 09:24:10 AM
Quote
This study claimed that without the GAC 2012 minimum would have been only 150k higher.

That is consistent with my findings  :

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi1272.photobucket.com%2Falbums%2Fy396%2FRobDekker%2FJunePredict_zpsquedrtdc.png&hash=5f80308985f70da31f29ef3d04f7ddf7)

based on June data, 2012 was pre-conditioned with low land snow cover and low ice concentration and low ice "area" which collaborated to produce a record low extent.
The GAC 2012 was just adding the proverbial frosting on the cake that year.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 02, 2016, 12:23:19 PM
ADS-NIPR Extent:
6,321,835 km2 (01 August)
Down 7,620,672 km2 (54.66%) from 2016 maximum of 13,942,507 km2 on 29 February.
3,144,380 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 116,275 km2 (-1.81%) from previous day.
Down 590,452 km2  (-8.54%) over past seven days (daily average: -84,350 km2).
Down 116,275 km2  (-.95%) for August (daily average: -116,275 km2).
885,576 km2 below 2000s average for this date.
137,399 km2 below 2010s average for this date.
146,308 km2 below 2015 value for this date.
239,435 km2 above 2012 value for this date.
Lowest year-to-date (01 January - 01 August) average.
4th lowest August to-date average.
4th lowest value for the date.
128 days this year (60.09% year-to-date) have recorded the lowest daily extent.
35 days (16.43%) have recorded the second lowest.
24 days (11.27%) have recorded the third lowest.
187 days in total (87.79%) have been among the lowest three on record.


CT Area:
4,039,888 km2 (02 August [Day 0.5836])
Down 8,881,470 km2 (68.73%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
1,805,879 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 97,276 km2 (-2.35%) from previous day.
Down 627,678 km2 (-13.58%) over past seven days (daily average: -89,668 km2).
Down 241,338 km2 (-2.17%) for August (daily average: -120,669 km2).
1,025,733 km2 below 2000s average for this date.
290,693 km2 below 2010s average for this date.
206,603 km2 below 2015 value for this date.
252,692 km2 above 2012 value for this date.
2nd lowest value for the date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' shadow area numbers as calculated from NSIDC data. The official numbers will be substituted in if/when available. In the meantime, thanks, Wipneus!
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 02, 2016, 04:15:40 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Mon 2016.5781  -40.1  4.281226 +156.9 13.572847  +116.8 17.854073
Tue 2016.5808 -144.1  4.137164 +187.3 13.760145   +43.2 17.897309
Wed 2016.5836  -97.1  4.040073 -114.9 13.645262  -212.0 17.685335
Thu 2016.5863  -90.9  3.949171  -36.5 13.608778  -127.4 17.557949


Very little (less than 10k) of this can be attributed to the first of the month effect. Most of the decline was in the CAB: -46k.

Shadow NSIDC extent was 6.5017 dropping -162.9k. At most -25k can be caused by the new monthly ice mask (aka first of the month effect). Many regions can be mentioned Laptev (-32k), Chukchi (-29k), Beaufort (-24k), Hudson (-20k) and CAB (-19k).

As always, the attached delta map shows the numbers graphically.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 02, 2016, 05:07:21 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Mon 2016.5781  -40.1  4.281226 +156.9 13.572847  +116.8 17.854073
Tue 2016.5808 -144.1  4.137164 +187.3 13.760145   +43.2 17.897309
Wed 2016.5836  -97.1  4.040073 -114.9 13.645262  -212.0 17.685335
Thu 2016.5863  -90.9  3.949171  -36.5 13.608778  -127.4 17.557949


Thanks, Wipneus. That drops 2016 to-date SIA lower than the absolute minima recorded in every year prior to 2007 (1979-2006). With 5-6 weeks left, beating out 2013 (3.55M), 2014 (3.48M), and 2009 (3.43M) should be easy. Then we should eventually get to the tight cluster of years including 2007, 2008, 2010, 2011, and 2015, which all lie within 190k of each other. Then, far below and almost certainly untouchable, sits 2012.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 03, 2016, 05:37:38 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Tue 2016.5808 -144.1  4.137164 +187.3 13.760145   +43.2 17.897309
Wed 2016.5836  -97.1  4.040073 -114.9 13.645262  -212.0 17.685335
Thu 2016.5863  -90.9  3.949134  -36.2 13.609103  -127.1 17.558237
Fri 2016.5890  +18.2  3.967332 +103.7 13.712817  +121.9 17.680149


The uptick is mostly caused by the CAB (+28k) and CAA (+14k).

Shadow NSIDC extent is now  6.3851 dropping -116.6k. Some big declines in Laptev (-60k), Kara (-35k), Baffin (-28k) and Beaufort (-25k). The CAA went opposite (+33k).

There is a delta map for the graphical touch.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on August 04, 2016, 04:04:16 PM
A drop of 188k takes the daily NSIDC extent down to 2nd lowest on record.

It also puts the 7 day loss up to 942k, and means that we only have to average a 138k drop over the next 2 days to achieve a mega melt week (>1,000,000km2).

Using the 5 days average, we have now dropped below the minima of 14 previous years,  1979-1983, 1986-1989, 1992, 1994, 1996, 1997 and 2001

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fu94GoV1.png&hash=6498cea29660130c6ffab490e153f2e6)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 04, 2016, 06:23:15 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.5836  -97.1  4.040073 -114.9 13.645262  -212.0 17.685335
Thu 2016.5863  -90.9  3.949134  -36.2 13.609103  -127.1 17.558237
Fri 2016.5890  +17.6  3.966762 +104.1 13.713220  +121.7 17.679982
Sat 2016.5918  -37.6  3.929124 +195.1 13.908352  +157.5 17.837476



An uptick in the CAB (+38k) is the cause for a small total. Laptev (-22k) and CAA (-17k) are the biggest decliners.

Shadow NSIDC extent is now 6.1973 dropping -187.8k. Laptev keeps falling hard (-56k), followed by CAA (-39k), Baffin (-29k) and Beaufort (-25k).

Where ice cover grows, where it shrinks, see it on the attached delta map.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 05, 2016, 04:39:03 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.5863  -90.9  3.949134  -36.2 13.609103  -127.1 17.558237
Fri 2016.5890  +17.6  3.966762 +104.1 13.713220  +121.7 17.679982
Sat 2016.5918  -37.6  3.929124 +195.1 13.908299  +157.4 17.837423
Sun 2016.5945   -4.2  3.924892  +37.6 13.945875   +33.3 17.870767

Only small regional changes, Laptev (-15k) and CAA (+15k) changed most.

Shadow NSIDC extent is now 6.2668  nd increase of +69.6k. Laptev  and CAA caused the rebound (both +46k). The ESS did compensate a bit with -33k.

That can all be seen in the attached delta map.
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on August 06, 2016, 04:58:43 AM
Seems that today we have an important ASI compaction and/or flash melt.

First image from , Neven ASI Blog (http://neven1.typepad.com/blog/2016/08/piomas-august-2016.html)

Title: Re: 2016 sea ice area and extent data
Post by: S.Pansa on August 06, 2016, 06:06:06 AM
Seems that today we have an important ASI compaction and/or flash melt.
 ...]
Looking at this area with NASA Worldview it seems to me that most of the concentration-change is due to a change in cloud cover (see the two pics below). If you zoom in (http://go.nasa.gov/2aI5fyn) you can see that there is definitely some melting going on. But the changes do not look that massive between the 4th and 5th - at least to my eyes.
Title: Re: 2016 sea ice area and extent data
Post by: Glenn Tamblyn on August 06, 2016, 10:38:28 AM
Juan

Flash melt maybe, but the second graph looks suspect. That is a strange near vertical line where the concentration suddenly transitions from 70's to 90's. Given how much lower area there was on the first graph that looks strange. Artifact from a satellite pass?
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on August 06, 2016, 03:15:41 PM
S. Pansa & Glenn Tamblyn:

You read my second thought about this picture (I went to bed thinking about it). Seems that there has been a lot of change on Chukchi, East Siberian Sea and even the Arctic Basin, but at the same time, some floes stayed at the same place, like they did not moved with currents or winds. Seems that the satellite is mistakenly taking clouds as ice on the right side of Chukchi. We will have to wait for the next Bremen pictures (to keep the same source).
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 06, 2016, 05:14:50 PM

day  CT-date       NH               SH                Global
Fri 2016.5890  +17.6  3.966762 +104.1 13.713220  +121.7 17.679982
Sat 2016.5918  -37.6  3.929124 +195.1 13.908299  +157.4 17.837423
Sun 2016.5945   -4.4  3.924752  +37.5 13.945810   +33.1 17.870562
Mon 2016.5973 -123.6  3.801130   -2.3 13.943550  -125.9 17.744680

All the work of CAB (-64k), ESS (-28k) and Laptev (-24k).

Shadow NSIDC extent is now 6.1836 dropping  -83.2. Only one mighty lifter to mention:
ESS with -57k. Hudson went elsewhere and rebounded +25k.

I have attached the delta map for another vieuw.
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on August 07, 2016, 04:23:57 AM
Back to normal (not all that ice). The Arctic sea ice melt is advancing...

Thanks Wipneus, for your daily information!
I don´t like the "Seems..." in my previous messages! Your information clearly quantifies the looses!
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on August 07, 2016, 07:58:34 AM
Thank you Juan,

I think it was seaicesailor who first noted that the ice north-north-east of Wrangel island showed a "path" of weak ice, with holes forming along the way north, and he suggested this had to do with ocean currents from the Bering.

I found this image of the currents out of the Bering Strait into the Arctic, and I think seaicesailor does have a point : There is a current out of the Bering that flows right next to (to the east of) Wrangel island, through "Harald Valley" and due north, which matches with the location where (at least on AMSR) Arctic sea ice is forming increasingly large polynia :

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fimages.slideplayer.com%2F24%2F6955608%2Fslides%2Fslide_6.jpg&hash=d84d71a045f8e31785f6811f80847334)

Elsewhere I found that this current is called "Anadyr" water, and since it comes directly out of the Bering, it can very well have contributed to the weakening of the ice along the current (by bottom melt) which now culminates in dropping off the AMSR2 radar.

This does not bode well for the ice in that area, which is already extremely fragmented as JayW's animations clearly show.
Title: Re: 2016 sea ice area and extent data
Post by: slow wing on August 07, 2016, 08:34:30 AM
Very interesting, Rob and SeaIceSailor, thanks!
Title: Re: 2016 sea ice area and extent data
Post by: seaicesailor on August 07, 2016, 12:03:32 PM
Thank you Juan,

I think it was seaicesailor who first noted that the ice north-north-east of Wrangel island showed a "path" of weak ice, with holes forming along the way north, and he suggested this had to do with ocean currents from the Bering.

I found this image of the currents out of the Bering Strait into the Arctic, and I think seaicesailor does have a point : There is a current out of the Bering that flows right next to (to the east of) Wrangel island, through "Harald Valley" and due north, which matches with the location where (at least on AMSR) Arctic sea ice is forming increasingly large polynia :
...
Elsewhere I found that this current is called "Anadyr" water, and since it comes directly out of the Bering, it can very well have contributed to the weakening of the ice along the current (by bottom melt) which now culminates in dropping off the AMSR2 radar.

This does not bode well for the ice in that area, which is already extremely fragmented as JayW's animations clearly show.
Hey Rob thank you! I was waiting to download another image later this week.
Right now the polynya is being moved laterally with the ice. We'll see if the ocean opens up again in the previous location, but anyway the polynya is so huge now that we may end up not seeing a thing.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 07, 2016, 01:44:15 PM
ADS-NIPR Extent:
5,868,941 km2 (06 August)
Down 8,073,566 km2 (57.91%) from 2016 maximum of 13,942,507 km2 on 29 February.
2,691,486 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 93,189 km2 (-1.56%) from previous day.
Down 665,397 km2  (-10.18%) over past seven days (daily average: -95,057 km2).
Down 569,169 km2  (-4.65%) for August (daily average: -94,862 km2).
988,410 km2 below 2000s average for this date.
217,865 km2 below 2010s average for this date.
283,861 km2 below 2015 value for this date.
374,805 km2 above 2012 value for this date.
Lowest year-to-date (01 January - 06 August) average.
3rd lowest August to-date average.
3rd lowest value for the date.
128 days this year (58.72% year-to-date) have recorded the lowest daily extent.
35 days (16.06%) have recorded the second lowest.
29 days (13.3%) have recorded the third lowest.
192 days in total (88.07%) have been among the lowest three on record.


CT Area:
3,801,130 km2 (06 August [Day 0.5973])
Down 9,120,228 km2 (70.58%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
1,567,121 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 123,622 km2 (-3.15%) from previous day.
Down 480,096 km2 (-11.6%) over past seven days (daily average: -68,585 km2).
Down 480,096 km2 (-4.31%) for August (daily average: -68,585 km2).
1,018,109 km2 below 2000s average for this date.
238,507 km2 below 2010s average for this date.
150,878 km2 below 2015 value for this date.
375,763 km2 above 2012 value for this date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' shadow area numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!





Title: Re: 2016 sea ice area and extent data
Post by: Bill Fothergill on August 07, 2016, 02:23:06 PM
Thank you Juan,

I think it was seaicesailor who first noted that the ice north-north-east of Wrangel island showed a "path" of weak ice, with holes forming along the way north, and he suggested this had to do with ocean currents from the Bering.
...

...
Right now the polynya is being moved laterally with the ice. We'll see if the ocean opens up again in the previous location, but anyway the polynya is so huge now that we may end up not seeing a thing.


Yep, that's certainly getting closer to just being open water.

On the other hand, for the last 10 days or so, I've being watching the beginnings of a polynya stretching from the Vilkitsky Strait in the direction of the New Siberian Islands. In that time, not much has really developed, but there is a specific reason for the interest in that particular region.

You may be aware of the Polar Ocean Challenge: in which the 15-metre, aluminium skinned yacht, Northabout, is attempting a single season, West-to-East circumnavigation of both the Northern Sea Route and the Northwest Passage. For the last week, Northabout has been anchored at Ostrov Pilota Makhotkina, in the Nordenskiöld Archipelago waiting for the passage into the Laptev to open up.
Title: Re: 2016 sea ice area and extent data
Post by: seaicesailor on August 07, 2016, 03:42:36 PM
Paper by R Woodgate and others about the role of anomalous heat flux on the ice extent loss in 2007
http://psc.apl.washington.edu/HLD/Bstrait/BS2007Heat.html (http://psc.apl.washington.edu/HLD/Bstrait/BS2007Heat.html)
Very much on-topic given the current amount of ice under menace in Chukchi and around. Potentially could be responsible of up to 2 m. km2 in the entire melting season. Not saying this is the case this year, but gives an idea that its effect may become quite visible.
One of the effects that this heat flux can cause is a persistence of heat transport around and beneath the ice during fall and winter given that it takes time for the Bering inflow to slow down or even reverse. HYCOM shows a recent acceleration of the inflow, possibly due to prevalent Northwards winds in the current weather pattern. Dilated melting season then?

(https://www7320.nrlssc.navy.mil/hycomARC/navo/beaufortsss_nowcast_anim30d.gif)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 07, 2016, 04:27:03 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.5918  -37.6  3.929124 +195.1 13.908299  +157.4 17.837423
Sun 2016.5945   -4.4  3.924752  +37.5 13.945810   +33.1 17.870562
Mon 2016.5973 -123.7  3.801093   -2.2 13.943580  -125.9 17.744673
Tue 2016.6000 -125.5  3.675573  -37.8 13.905788  -163.3 17.581361


It happened in the CAB: -134k. "Lakes" went up +31k (no doubt all false ice, CT is what it is).

Shadow NSIDC extent is now 6.0675 dropping -116.1k. CAB was the main decliner (-37k) followed by Hudson (-20k), Laptev (-18k) and Greenland Sea (-16k).

Attached is the delta map of the day.
Title: Re: 2016 sea ice area and extent data
Post by: Steven on August 07, 2016, 04:39:48 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

2016.6000  ...   3.675573 

Currently 2nd lowest.  It is 335k above 2012,   19k below 2011,  and 157k below 2007:

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FX1XJJgY.png&hash=9d3976fa931fa7b9c652c3f76a1da95a)
Title: Re: 2016 sea ice area and extent data
Post by: TerryM on August 07, 2016, 07:52:58 PM
Wipneus
With shore temperatures as high as 25C at the southern end of James Bay I think it's safe to consider that there is no more ice building or busting in Hudson Bay than there is in Lake Erie. Worldview appears to agree that clouds are the only extant white patches.
Terry
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on August 08, 2016, 12:58:20 PM
Update for the week to August 6th

The current 5 day trailing average is on 6,220,000km2 while the 1 day extent is at 6,067,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,659,000km2, an increase from -1,462,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at +63,000km2, a decrease from +272,000km2 last week. We're currently 3rd lowest on record, up from 4th last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FKQwWdXu.png&hash=0cb3f3a8b32048250c6ae7b9997d6035)

The average daily change over the last 7 days was -107.4k/day, compared to the long term average of -79.4k/day, and the 07, 11 and 12 average of -77.5k/day.
The average long term change over the next week is -66.0k/day, with the 07, 11, and 12 average being -98.9k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F1bSFl5p.png&hash=4b1aa99769950a47821ab82636eb8013)

The extent loss so far this August is the 2nd largest on record. To achieve the largest monthly loss, a drop of at least 85.1k/day is required (requiring ~85.8k/day with with single day values), while the smallest loss requires a drop less than 23.7k/day (<19.1k with single day values) and an average loss requires a drop of 45.0k/day (~42.3k/day with single day values).

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F4j0ETFx.png&hash=fb6a23a22e7884f7e00ca46f0585134a)

The extent loss in July was the 18th smallest on record, while the average extent was the 3rd lowest on record.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FjijUUdd.png&hash=3fac27aa73acc327e9d766f376f22fad)

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FmhYXz2Z.png&hash=b65b6fd60e5ff133af677b2ebc71bf8f)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on August 08, 2016, 01:08:50 PM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FuOFfoX2.png&hash=d224aae257ded818e667788e879b546a)

Some stats on the difference between the current 5 day extent and previous minima

Diff.............No of Years.....Percentage
Below..............18.............48.6%
+0-100k............1..............2.7%
+100-250k.........4.............10.8%
+250-500k.........3..............8.1%
+500-1000k.......2..............5.4%
>1000k.............9.............24.3%
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 08, 2016, 04:31:16 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.5945   -4.4  3.924752  +37.5 13.945810   +33.1 17.870562
Mon 2016.5973 -123.7  3.801093   -2.2 13.943580  -125.9 17.744673
Tue 2016.6000 -124.7  3.676421  -37.7 13.905869  -162.4 17.582290
Wed 2016.6027   +2.0  3.678457   -3.7 13.902207    -1.6 17.580664


None of the regions changed noteworthy.

Shadow NSIDC extent is now 5.9610 dropping -106.5. Highest decliner was the CAB (-50k), followed by Hudson (-23k), CAA (-17k) and Chukchi (-16k).

Have a look at the attached delta map and see what the opening of a "bite" looks like
Title: Re: 2016 sea ice area and extent data
Post by: Neven on August 08, 2016, 04:41:26 PM
Flash-unflash-flash-unflash?  :)

Bumpy ride...
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on August 08, 2016, 04:48:06 PM
Flash-unflash-flash-unflash?  :)

Bumpy ride...

It is notorious the difference between area change and extent change. While area did not change, we have a century drop in extent!
Title: Re: 2016 sea ice area and extent data
Post by: Siffy on August 08, 2016, 05:06:34 PM
Flash-unflash-flash-unflash?  :)

Bumpy ride...

More like Unflash, flash, flash, unflash.

 :P
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 08, 2016, 05:33:02 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.5945   -4.4  3.924752  +37.5 13.945810   +33.1 17.870562
Mon 2016.5973 -123.7  3.801093   -2.2 13.943580  -125.9 17.744673
Tue 2016.6000 -124.7  3.676421  -37.7 13.905869  -162.4 17.582290
Wed 2016.6027   +2.0  3.678457   -3.7 13.902207    -1.6 17.580664

That still leaves 2016 in second place, though barely ahead of 2007 (which went on to lose more than half a million km2 of area over the next week, including a near double century drop). Perhaps more meaningfully, however, the gap between first place 2012 and 2016 has widened to its largest yet at 475k, thanks to the former year's much-talked-about GAC. The effects of the GAC were over on 0.6028, however, so there's a chance to play a little catch-up. Having said that, though, first place is firmly out of reach at this point, with just 4-5 weeks left to lose 1.45M km2. I do think second place is probable. There's a massive lead of 671k between first place 2012 and current second place 2011, so this year needs to see a further drop of "just" 774k, a not unreasonable amount: only one year in the past ten (2006) has failed to see that much additional area loss from here onward, and the average drop from now through annual minimum for those same ten years has been 927k.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 08, 2016, 06:46:31 PM
Flash-unflash-flash-unflash?  :)

Bumpy ride...

Time of year when temperatures hoovering around freezing point. The daily cycle of temperatures gets more prominent as well. Since the satellite orbits do not exactly repeat after 24 hours, I speculate there may be a cause and effect.

animation needs a click to start
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 09, 2016, 04:35:27 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Mon 2016.5973 -123.7  3.801093   -2.2 13.943580  -125.9 17.744673
Tue 2016.6000 -124.7  3.676421  -37.7 13.905869  -162.4 17.582290
Wed 2016.6027   +2.0  3.678457   -4.0 13.901830    -2.0 17.580287
Thu 2016.6055   -8.9  3.669541  +60.2 13.962020   +51.3 17.631561


CAB area increased +32k. Other regions changed little.

Shadow NSIDC extent is 5.9239  dropping -37.1k. The CAB changed -28k, CAA trailed at -18k. Baffin increased +22k.

The attached delta map shows exactly where the changes are taking place.
Title: Re: 2016 sea ice area and extent data
Post by: Pmt111500 on August 09, 2016, 06:07:54 PM
Flash-unflash-flash-unflash?  :)

Bumpy ride...

Time of year when temperatures hoovering around freezing point. The daily cycle of temperatures gets more prominent as well. Since the satellite orbits do not exactly repeat after 24 hours, I speculate there may be a cause and effect.

animation needs a click to start

This. You get a pretty stable curve averaging over 2 weeks but the n you lose all the interesting discussion on ups and downs, which could still be real but not as pronounced as the raw numbers state... I in fact dug the orbital period of the satellite in question out and thought to use a multiple of that as the averaging period but never got to it. The easy to do 13 or 15 day weighted averages were enough for me, as it looked like it pretty much smoothed the weather effects out. 
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 10, 2016, 06:40:57 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Tue 2016.6000 -124.7  3.676421  -37.7 13.905869  -162.4 17.582290
Wed 2016.6027   +2.0  3.678457   -4.0 13.901830    -2.0 17.580287
Thu 2016.6055   -9.0  3.669434  +59.6 13.961410   +50.6 17.630844
Fri 2016.6082  -49.8  3.619676   -5.6 13.955855   -55.3 17.575531


The only region that changed enough for me to mention is "lakes". A lot of spurious ice  disappeared there: -18k.

Shadow NSIDC extent is now 5.9060 dropping  -17.9. The CAB lost -32k, CAA -18k but the Hudson increased +34k.

It can all been seen in the delta map that is attached.
Title: Re: 2016 sea ice area and extent data
Post by: Nick_Naylor on August 10, 2016, 07:24:15 PM
The image seems to be showing a downward arrow. Probably an omen that area and extent are going to take a bit of a dive the next few days.
Title: SIPN Webinar on uncertainty in sea ice extent
Post by: seaice.de on August 11, 2016, 07:30:02 AM
The Sea Ice Prediction Network (SIPN) announces a call for registration
for an open webinar entitled "Uncertainty in Satellite-Derived Sea Ice
Extent Estimates" presented by Walt Meier, NASA Goddard Space Flight
Center. This event is scheduled for Tuesday, 23 August 2016
from 10:00 a.m. to 11:00 a.m. AKDT.
We request that all participants pre-register to join any SIPN webinar.
Anyone with an e-mail address can register, and participation is free.
To register for this webinar, go to:
https://www.arcus.org/sipn/meetings/webinars/register. (https://www.arcus.org/sipn/meetings/webinars/register.)

This webinar is designed for the sea ice research community and others
interested in information about the uncertainty in sea ice extent
estimates from remotely-sensed data. While this is an open event,
attendees should be aware that the discussions will largely be of a
technical nature. The speaker will be Walt Meier, NASA Goddard Space
Flight Center.

Walt Meier is a research scientist at the NASA Goddard Space Flight
Center Cryospheric Sciences Laboratory. His research focuses on remote
sensing of sea ice, development of new sea ice products and sea ice
climate data records, and analyzing changes in the Arctic sea ice cover.
He has been principal investigator on a project to create a sea ice
climate data record.

Meier’s presentation will focus on uncertainty in sea ice extent
estimates from remotely-sensed data. Arctic sea ice extent estimates
from remote sensing data (e.g., passive microwave sensors like Advanced
Microwave Scanning Radiometer-Earth Observing System [AMSR-E] and
others) are widely used to project sea ice trends, initialize models,
and evaluate model forecasts. As with all kinds of remote observations,
this method of estimating sea ice extent has strengths and weaknesses
that result in unique kinds of uncertainty. To date, however, little
effort has been made to provide an uncertainty range of extent estimates
from satellite data. Meier will discuss our current understanding of
these issues and propose various methods of estimating extent
uncertainty, with the aim of improving analyses of sea ice extent trends
and variability. Time for participant questions will follow the
presentation.

The webinar is scheduled for 10:00 a.m. to 11:00 a.m. AKDT (11:00 a.m.to
12:00 p.m. PDT, 12:00 p.m. to 1:00 p.m. MDT, 1:00-2:00 p.m. CDT, and
2:00-3:00 p.m. EDT) on Tuesday, 23 August 2016.

The webinar will be archived and available online after the event.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 11, 2016, 04:20:30 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.6027   +2.0  3.678457   -4.0 13.901830    -2.0 17.580287
Thu 2016.6055   -9.0  3.669434  +59.6 13.961410   +50.6 17.630844
Fri 2016.6082  -49.9  3.619535   -5.3 13.956136   -55.2 17.575671
Sat 2016.6110  -12.4  3.607119  -51.9 13.904270   -64.3 17.511389


CAB increased by +50k. Area decreased in the CAA (-23k) and Laptev (-17k).

Shadow NSIDC extent is now 5.7651 dropping -140.9k. The decline is led by CAA (-44k) followed by Hudson (-22k), Chukchi (-20k) and ESS (-18k).

As always the attached delta map may help to understand the numbers.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on August 12, 2016, 04:19:39 PM
Another large drop on the daily NSIDC extent, -142k. This takes us just 33k off 2007 in 2nd place, but still over 600k above 2012.

With the 5 day average, we've now dropped below 23 of the 37 previous minima. This includes all minima up to and including 1998, as well as 2000, 2001 and 2003. We're within 250k of 1999, 2002, 2004 and 2006 minima too.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FFF9Nv9S.png&hash=fb6cae53f50f1f718d2eb0e47d61538c)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 12, 2016, 06:02:45 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.6055   -9.0  3.669434  +59.6 13.961410   +50.6 17.630844
Fri 2016.6082  -49.9  3.619535   -5.3 13.956136   -55.2 17.575671
Sat 2016.6110  -12.6  3.606984  -45.9 13.910256   -58.4 17.517240
Sun 2016.6137  +29.5  3.636496  +29.0 13.939217   +58.5 17.575713


Big increases in the CAB: +89k. ESS (-22k) and CAA(-19k) cannot prevent an uptick.

Shadow NSIDC extent is now 5.6227 dropping -142.5k. Laptev is the leader: -48k, followed by CAA (-36k), Hudson (-36k), ESS (-23k) and Greenland Sea (-16k). The extent in the CAB increased +25k.

The attached delta map shows where the extent and area changes came from.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 12, 2016, 08:10:57 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.6055   -9.0  3.669434  +59.6 13.961410   +50.6 17.630844
Fri 2016.6082  -49.9  3.619535   -5.3 13.956136   -55.2 17.575671
Sat 2016.6110  -12.6  3.606984  -45.9 13.910256   -58.4 17.517240
Sun 2016.6137  +29.5  3.636496  +29.0 13.939217   +58.5 17.575713


That will drop 2016 back into 5th place behind 2012, 2011, 2015, and 2007. This will be the first time since January that 2016 trailed last year.

The current stall is reminiscent with the nine-day one that took place in the second week of August in 2014, where CT area flatlined, actually increasing by a total of 15k over the period (before falling by nearly 800k before the month ended).
Title: Re: 2016 sea ice area and extent data
Post by: Bill Fothergill on August 13, 2016, 01:01:32 PM
For any readers relatively new to the subject, the side-by-side layout for area and extent used by the Nansen Environmental & Remote Sensing Centre rather neatly illustrates the point made by Jim Pettit - even including the way 2014 went walk-about in August 2014.

http://arctic-roos.org/observations/ice-area-and-extent-in-arctic (http://arctic-roos.org/observations/ice-area-and-extent-in-arctic)

NB Unfortunately, as Nansen uses a sliding window approach to the times series, 2007 is no longer getting displayed, but it would, of course, be second to 2012 in area/extent around the time of the September minimum.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 13, 2016, 03:05:31 PM
ADS-NIPR Extent:
5,420,490 km2 (12 August)
Down 8,522,017 km2 (61.12%) from 2016 maximum of 13,942,507 km2 on 29 February.
2,243,035 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 73,342 km2 (-1.33%) from previous day.
Down 541,640 km2  (-9.08%) over past seven days (daily average: -77,377 km2).
Down 1,017,620 km2  (-8.32%) for August (daily average: -84,802 km2).
1,082,297 km2 below 2000s average for this date.
201,538 km2 below 2010s average for this date.
242,491 km2 below 2015 value for this date.
626,976 km2 above 2012 value for this date.
Lowest year-to-date (01 January - 12 August) average.
3rd lowest August to-date average.
3rd lowest value for the date.
128 days this year (57.14% year-to-date) have recorded the lowest daily extent.
35 days (15.63%) have recorded the second lowest.
35 days (15.63%) have recorded the third lowest.
198 days in total (88.39%) have been among the lowest three on record.


CT Area:
3,636,496 km2 (12 August [Day 0.6136])
Down 9,284,862 km2 (71.86%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
1,402,487 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Up 29,512 km2 (.82%) from previous day.
Down 288,256 km2 (-7.58%) over past seven days (daily average: -41,179 km2).
Down 644,730 km2 (-5.79%) for August (daily average: -49,595 km2).
905,509 km2 below 2000s average for this date.
142,760 km2 below 2010s average for this date.
49,754 km2 above 2015 value for this date.
523,395 km2 above 2012 value for this date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' shadow area numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 13, 2016, 05:07:44 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Fri 2016.6082  -49.9  3.619535   -5.3 13.956136   -55.2 17.575671
Sat 2016.6110  -12.6  3.606984  -45.9 13.910256   -58.4 17.517240
Sun 2016.6137  +29.5  3.636514  +28.9 13.939110   +58.4 17.575624
Mon 2016.6164  -78.5  3.558010  +51.5 13.990590   -27.0 17.548600


The CAB declined -40k with Laptev (-15k) second.

Shadow NSIDC extent is now 5.5517 dropping  -71.6. CAB (-31k) and ESS (-20k) dropped most.

Like every day, an delta image is attached for a visual perspective.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 14, 2016, 05:30:11 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.6110  -12.6  3.606984  -45.9 13.910256   -58.4 17.517240
Sun 2016.6137  +29.5  3.636514  +28.9 13.939110   +58.4 17.575624
Mon 2016.6164  -78.5  3.557990  +51.4 13.990507   -27.1 17.548497
Tue 2016.6192  +22.5  3.580469 +131.3 14.121842  +153.8 17.702311


CAB changed most and declined -20k.

Shadow NSIDC extent is 5.6220 an increase of +70.3k. Biggest uptick in the CAA (+35k) followed by Laptev (+17k).

Have a look at the attached delta map for the details.
Title: Re: 2016 sea ice area and extent data
Post by: Steven on August 14, 2016, 09:04:21 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:
...
2016.6192   ...   3.580469

That is the 5th lowest value on record for this date  (594k above 2012,  236k above 2007,  189k above 2011,  and 10k above 2015):


(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FUuoqd2H.png&hash=0a616d46ee53a8faedb5c86aaf221b3f)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on August 15, 2016, 12:18:40 PM
Update for the week to August 13th

The current 5 day trailing average is on 5,694,000km2 while the 1 day extent is at 5,622,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,723,000km2, an increase from -1,659,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at +229,000km2, an increase from +63,000km2 last week. We're currently 3rd lowest on record, the same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F26TCT2r.png&hash=c08729602aa4f2da578d505e07f1e002)

The average daily change over the last 7 days was -75.2k/day, compared to the long term average of -66.0k/day, and the 07, 11 and 12 average of -98.9k/day.
The average long term change over the next week is -53.7k/day, with the 07, 11, and 12 average being -70.1k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FONLm9ev.png&hash=33e05a6fcd1139b15c166a52ba89370e)

The extent loss so far this August is the 6th largest on record. To achieve the largest monthly loss, a drop of at least 88.9k/day is required (requiring ~95.4k/day with with single day values), while the smallest loss requires a drop less than 3.7k/day (+0.03k/day with single day values) and an average loss requires a drop of 33.3k/day (~33.0k/day with single day values).

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FHB8NYTV.png&hash=b311d312105d8bd34141dd986c50e849)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on August 15, 2016, 12:59:12 PM
(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FEsjSeYr.png&hash=8f9aa752be44b642f4e11ba39a46f227)

...Diff..... ......No of Years ......Percentage
Below........ ......26......... .......70.3%
0-100k..... ........1......... ........2.7%
100-250k..... .....0......... ........0.0%
250-500k..... .....1......... ........2.7%
500-1000k..... ...3......... ........8.1%
>1000k..... ...... 6......... ........16.2%
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 15, 2016, 04:21:40 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.6137  +29.5  3.636514  +28.9 13.939110   +58.4 17.575624
Mon 2016.6164  -78.5  3.557990  +51.4 13.990507   -27.1 17.548497
Tue 2016.6192  +23.1  3.581084 +131.4 14.121924  +154.5 17.703008
Wed 2016.6219  -76.7  3.504432 +105.5 14.227472   +28.9 17.731904


CAB and Laptev did it today: -71k and -32k. Kara increased by +17k.

Shadow NSIDC extent is now 5.4991 dropping -122.9k. All duw to a huge drop in Laptev: -110k. Kara in increased by +18k.

The delta map is attached as always.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 15, 2016, 04:54:14 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.6137  +29.5  3.636514  +28.9 13.939110   +58.4 17.575624
Mon 2016.6164  -78.5  3.557990  +51.4 13.990507   -27.1 17.548497
Tue 2016.6192  +23.1  3.581084 +131.4 14.121924  +154.5 17.703008
Wed 2016.6219  -76.7  3.504432 +105.5 14.227472   +28.9 17.731904


Thanks. That puts 2016 at 9th place, surpassing 2013's September minimum, which moves into 10th. Next up: 8th place 2014, then 7th place 2009. Those two should be easy, as both are less than 80k away. But the BIG question is whether 2016 will be able to then reach and (possibly surpass) the tight cluster comprised of 2015, 2010, 2008, 2007, and 2011; all five are between 400k and 600k away.

2012 is, of course, far away with a lead of 1.27M.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on August 16, 2016, 05:06:55 PM
Big drop on the NSIDC daily extent, -112k.

Single day extent is now less than 400k off the 2009, 2013 and 2014 minima.
5 day extent is less than 500k off the 2009 and 2013 minima, and just over 500k off the 2014 minimum.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 16, 2016, 05:18:36 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Mon 2016.6164  -78.5  3.557990  +51.4 13.990507   -27.1 17.548497
Tue 2016.6192  +23.1  3.581084 +131.4 14.121924  +154.5 17.703008
Wed 2016.6219  -76.4  3.504732 +105.6 14.227520   +29.2 17.732252
Thu 2016.6247 -169.7  3.335018  +84.3 14.311798   -85.4 17.646816


Big losses in the CAB (-96k) and CAA (-49k).

Shadow NSIDC extent is now 5.3866 dropping -112.6k. Losses in CAA (-122k), ESS (-30k) and Kara (-17k). Laptev rebounded +79k.

The daily changes can be seen on the attached delta map.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 16, 2016, 05:51:56 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Mon 2016.6164  -78.5  3.557990  +51.4 13.990507   -27.1 17.548497
Tue 2016.6192  +23.1  3.581084 +131.4 14.121924  +154.5 17.703008
Wed 2016.6219  -76.4  3.504732 +105.6 14.227520   +29.2 17.732252
Thu 2016.6247 -169.7  3.335018  +84.3 14.311798   -85.4 17.646816


SIA is now in 7th place. Additional SIA 2016 needs to lose in order to attain each of the remaining ranks:

6th: 2015: 242k
5th: 2010: 263k
4th: 2008: 332k
3rd: 2007: 416k
2nd: 2011: 431k
1st: 2012: 1102k
Title: Re: 2016 sea ice area and extent data
Post by: Darvince on August 16, 2016, 08:04:00 PM
All due to a huge drop in Laptev: -110k.
Losses in CAA (-122k),
Can you say flash melt much? :o
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 17, 2016, 01:49:12 PM
ADS-NIPR (IJIS) Extent:
5,173,737 km2 (16 August)
Down 8,768,770 km2 (62.89%) from 2016 maximum of 13,942,507 km2 on 29 February.
1,996,282 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 109,341 km2 (-2.07%) from previous day.
Down 482,442 km2  (-8.53%) over past seven days (daily average: -68,920 km2).
Down 1,264,373 km2  (-10.33%) for August (daily average: -79,023 km2).
1,103,958 km2 below 2000s average for this date.
187,131 km2 below 2010s average for this date.
296,907 km2 below 2015 value for this date.
706,946 km2 above 2012 value for this date.
Lowest year-to-date (01 January - 16 August) average.
3rd lowest August to-date average.
3rd lowest value for the date.
128 days this year (56.14% year-to-date) have recorded the lowest daily extent.
35 days (15.35%) have recorded the second lowest.
39 days (17.11%) have recorded the third lowest.
202 days in total (88.6%) have been among the lowest three on record.


CT Area:
3,335,018 km2 (16 August [Day 0.6246])
Down 9,586,340 km2 (74.19%) from 2016 maximum of 12,921,358 km2 on 29 March [Day 0.2384].
1,101,009 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 169,714 km2 (-4.84%) from previous day.
Down 334,416 km2 (-9.24%) over past seven days (daily average: -47,774 km2).
Down 946,208 km2 (-8.5%) for August (daily average: -55,659 km2).
1,048,044 km2 below 2000s average for this date.
365,189 km2 below 2010s average for this date.
259,835 km2 below 2015 value for this date.
392,672 km2 above 2012 value for this date.
* - NOTE: due to the prolonged absence of official CT sea ice area data, I've incorporated Wipneus' shadow area numbers as calculated from NSIDC data. The official numbers will be inserted if/when available. In the meantime, thanks, Wipneus!

Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on August 17, 2016, 03:53:37 PM
With a drop of 136k, the daily NSIDC extent has dropped back to 2nd lowest for the first time since July 7th.
Just 263k required for the daily extent to drop below the minima of 2009, 2013 and 2014.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 17, 2016, 05:17:09 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Tue 2016.6192  +23.1  3.581084 +131.4 14.121924  +154.5 17.703008
Wed 2016.6219  -76.4  3.504732 +105.6 14.227520   +29.2 17.732252
Thu 2016.6247 -169.7  3.335046  +84.3 14.311867   -85.3 17.646913
Fri 2016.6274  -74.5  3.260497  +74.3 14.386207    -0.2 17.646704


With the contributions of the CAB (-45k) and ESS (-17k).

Shadow NSIDC extent is now 5.2515 dropping -135.1. Done by the CAB (-72k), ESS (-26k) and CAA (-15k).

The attached delta map takes allows another view.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 17, 2016, 05:35:21 PM
If 2016 area loss were to end now, shadow SIA would still be in 7th place. Here's a list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 167k
5th: 2010: 189k
4th: 2008: 257k
3rd: 2007: 342k
2nd: 2011: 356k
1st: 2012: 1027k
Title: Re: 2016 sea ice area and extent data
Post by: seaicesailor on August 17, 2016, 07:02:41 PM
It is outstanding that almost no blue appears either in the Atlantic or the Pacific side on the last two concentration maps above. Only Laptev edge shows some.
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on August 17, 2016, 07:31:50 PM
It is outstanding that almost no blue appears either in the Atlantic or the Pacific side on the last two concentration maps above. Only Laptev edge shows some.
That drift map is really awful for the ice.  Everything along the edges is being dispersed into much warmer water. Laptev ice is being driven into warm near shore. Chukchi and near-CAB is driven towards warmer Chukchi and Beaufort water.   All across the Atlantic side, from the Fram to past Franz Josef, ice is being driven towards water that is 1 to 10+(!)C above normal.   And all the while more heat is being drawn up from depth in the middle of the pack.

Noted elsewhere, that heat anomaly in the Barents and Kara may be key to maintaining the strength of the current Cyclone.  NOAA image provided for reference.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on August 18, 2016, 04:15:14 PM
Surprisingly, a small increase in the NSIDC daily extent was recorded yesterday, +11k.

So we're back to 3rd lowest again, and over 700k off 2012.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 18, 2016, 04:30:48 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.6219  -76.4  3.504732 +105.6 14.227520   +29.2 17.732252
Thu 2016.6247 -169.7  3.335046  +84.3 14.311867   -85.3 17.646913
Fri 2016.6274  -74.5  3.260544  +73.9 14.385759    -0.6 17.646303
Sat 2016.6301  -31.6  3.228956  +39.9 14.425620    +8.3 17.654576


Declines in the CAB (-25k) and Greenland Sea (-15k). The area in the CAA increased by +20k.

Shadow NSIDC extent is now 5.2616 an increase of +10.1k. That is due to an rebound in the CAA (+60k). CAB continued its decline with -46k.

As always there is the attached delta map which shows the data in another way.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 18, 2016, 04:53:03 PM
If 2016 area loss were to end now, shadow SIA would still be in 7th place. Here's a list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 136k
5th: 2010: 157k
4th: 2008: 226k
3rd: 2007: 310k
2nd: 2011: 325k
1st: 2012: 995k

On a related note: were the remainder of the SIA melt season to proceed exactly as 2013 did from this point onward, 2016 would set a new record.
Title: Re: 2016 sea ice area and extent data
Post by: Juan C. García on August 18, 2016, 06:05:42 PM
If 2016 area loss were to end now, shadow SIA would still be in 7th place. Here's a list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 136k
5th: 2010: 157k
4th: 2008: 226k
3rd: 2007: 310k
2nd: 2011: 325k
1st: 2012: 995k

On a related note: were the remainder of the SIA melt season to proceed exactly as 2013 did from this point onward, 2016 would set a new record.

Good data Jim! Thank you!
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 19, 2016, 04:51:22 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.6247 -169.7  3.335046  +84.3 14.311867   -85.3 17.646913
Fri 2016.6274  -74.5  3.260544  +73.9 14.385759    -0.6 17.646303
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204134  +98.6 14.523893   +73.9 17.728027


It is all in the CAB: -29k.

Shadow NSIDC extent is now 5.2082 dropping  -53.4k. CAB is again the major contributor (-59k) while the CAA increases by +16k.

The attached delta map allows another view where the ice comes and where it goes.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 19, 2016, 05:03:18 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.6247 -169.7  3.335046  +84.3 14.311867   -85.3 17.646913
Fri 2016.6274  -74.5  3.260544  +73.9 14.385759    -0.6 17.646303
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204134  +98.6 14.523893   +73.9 17.728027


Even with that second consecutive below-average drop in area, 2016 would still finish in 7th place were the melt season to end today. But we're getting closer to the head of the pack, albeit s-l-o-w-l-y now; here's a list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 111k
5th: 2010: 133k
4th: 2008: 201k
3rd: 2007: 285k
2nd: 2011: 300k
1st: 2012: 971k
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on August 19, 2016, 06:29:00 PM
It is not moving slowly. It is being ripped apart each and every day, the clouds are masking the damage. I would bet that the "real" area is now below all minimums besides 07/11/12.

You can see large inexplicable blue areas flashing back and forth... with AMSR2's data yday and the small decrease today that probably means we are going to see a 150-200K loss tomorrow.
Title: Re: 2016 sea ice area and extent data
Post by: Peter Ellis on August 19, 2016, 06:31:35 PM
Clouds can make the apparent concentration go down as well as up.  All we can say is that the data are currently noisier than usual.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 19, 2016, 07:13:47 PM
It is not moving slowly. It is being ripped apart each and every day, the clouds are masking the damage. I would bet that the "real" area is now below all minimums besides 07/11/12.

You can see large inexplicable blue areas flashing back and forth... with AMSR2's data yday and the small decrease today that probably means we are going to see a 150-200K loss tomorrow.

Oh, I'm not doubting that the ice is disappearing; that's why I stated that the numbers were going down slowly, and not the ice. But the numbers are all we have to go by and refer to. Your "bets" and "probablys" may very well come to pass--in fact, they could be understatements, given what's happening--but, in the end, data rules.

FWIW, 2016 SIA is almost certainly going to end up in that 670k gap where 2nd place awaits...
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on August 19, 2016, 07:14:17 PM
Clouds can make the apparent concentration go down as well as up.  All we can say is that the data are currently noisier than usual.

true that, while in times of sharp decline the clouds will hide some of the most recent losses and in times of refreezing and compaction the clouds can hide some of that. since we're in a phase of sharp decline it's quite clear to which side the clouds are impacting the data.
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on August 19, 2016, 07:21:03 PM
It is not moving slowly. It is being ripped apart each and every day, the clouds are masking the damage. I would bet that the "real" area is now below all minimums besides 07/11/12.

You can see large inexplicable blue areas flashing back and forth... with AMSR2's data yday and the small decrease today that probably means we are going to see a 150-200K loss tomorrow.

Oh, I'm not doubting that the ice is disappearing; that's why I stated that the numbers were going down slowly, and not the ice. But the numbers are all we have to go by and refer to. Your "bets" and "probablys" may very well come to pass--in fact, they could be understatements, given what's happening--but, in the end, data rules.

FWIW, 2016 SIA is almost certainly going to end up in that 670k gap where 2nd place awaits...

Why would it almost certainly end up there? I think it will go below 2012...

The key difference between 2012 and this year is that 2012 still had some semblance of structure... when the winds were blowing, sure it compacted like crazy, but the key thing is that it could actually compact.

This is not the case in 2016 except for a very small area N of the CAA/Greenland... everywhere else has lost structure completely! And with no structural integrity there is nothing to "compact" onto. Even last year, we had a 'compactable' base -- this year, the heart of the CAB has seemingly been ripped out, to much ill effect.

I will try and illustrate later, but I've seen a few people bring up the point that this year we are dealing with a surge of warm Atlantic water entering the ATL/Siberian side of the Arctic... and basically disrupting the freshwater lense over much of the Arctic. This would also explain why there has been such sudden and drastic melt over areas that are normally immune...

In any case, the models have now gone more gung-ho with the D2-3 cyclone, with some now pushing it to the strength of the one we just had. Models have gone slightly weaker with the following event, but still indicate potential for 970 or lower.

With the GFS/etc now showing some epic Pacific ridging into the CAB through/past D10, melt season has a long way to go...

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fwww.tropicaltidbits.com%2Fanalysis%2Fmodels%2Fgfs%2F2016081912%2Fgfs_mslpa_nhem_41.png&hash=4629a711d0e4e43c5901ccf91230c40b)
Title: Re: 2016 sea ice area and extent data
Post by: seaicesailor on August 19, 2016, 07:37:48 PM
I would say the pack now has a huge potential for compaction, being at record low levels.
We dont have to wait 10 days for pretty extreme events, this is Tuesday 23 to 25.
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on August 19, 2016, 08:08:46 PM
I would say the pack now has a huge potential for compaction, being at record low levels.
We dont have to wait 10 days for pretty extreme events, this is Tuesday 23 to 25.
I think the problem we are seeing this year is there is too much open water for compaction to be effective... eg, if you are "compacting" an extent of 1M SQ KM with an area of 300-400K KM2 (that is also thin), the movement alone makes the ice go 'poof' so instead of a meaningful agglomeration as an end result, you have nothing...

This does not hold for the area immediately N of the CAA & NW of Greenland, but for everywhere else, "compaction" seems to be translating into straight-up melting this yr instead of yielding any positive effects (more structural stability, etc).
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on August 19, 2016, 08:16:05 PM
I would say the pack now has a huge potential for compaction, being at record low levels.
We dont have to wait 10 days for pretty extreme events, this is Tuesday 23 to 25.
I think the problem we are seeing this year is there is too much open water for compaction to be effective... eg, if you are "compacting" an extent of 1M SQ KM with an area of 300-400K KM2 (that is also thin), the movement alone makes the ice go 'poof' so instead of a meaningful agglomeration as an end result, you have nothing...

This does not hold for the area immediately N of the CAA & NW of Greenland, but for everywhere else, "compaction" seems to be translating into straight-up melting this yr instead of yielding any positive effects (more structural stability, etc).
I'm anticipating that with the remnants of the Wendel Island "bridge" and a large slug of the Laptev. 

What will happen in that scary section of low concentration north of 85 is still uncertain.

That wind flow from the on-coming dipole is bad news, possibly very bad news, for the ice along the Atlantic edge.
Title: Re: 2016 sea ice area and extent data
Post by: RoxTheGeologist on August 19, 2016, 08:43:38 PM
I would say the pack now has a huge potential for compaction, being at record low levels.
We dont have to wait 10 days for pretty extreme events, this is Tuesday 23 to 25.

Assuming there is anything left to compact!.. Ice moving towards the Atlantic doesn't seem like a recipe for compaction, just further extensive thinning and melting. As the ice thins I'd assume that the ability to damp swell and waves decrease, and we are looking at fetches of 100's if not 1000's of kms. With a fetch of under 600 km, a velocity of 40 kmh, we can expect a swell inside the Arctic basin of 2-3m depending on the length of time the wind is blowing in the same direction. The wave period will be around 6 seconds, giving a wavelength of something like 60m, and more worryingly, disturbing water to a depth of 30m.



Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 19, 2016, 08:53:32 PM
Why would it almost certainly end up there? I think it will go below 2012...

One supposes it's theoretically possible for an additional 971,000 square kilometers of area to vanish over the next 3-and-a-half weeks or so, but given how that amount is double the average loss from today through minimum for the last ten years, I wouldn't put any money on it. At least not just yet.

Title: Re: 2016 sea ice area and extent data
Post by: Tealight on August 20, 2016, 12:25:50 AM
I updated my August forecast with the latest area values and the previous storm only managed to bring sea ice area within +1 standard deviation of my forecast. The next storm needs to be at least as powerful as the last one to force area values into the -1 standard deviation range. Anyone who bets on a new record low this year should probably pray for a third storm in September.
Title: Re: 2016 sea ice area and extent data
Post by: slow wing on August 20, 2016, 12:42:00 AM
Tealight, I appreciate you doing the model - and also others who do similar. It's a service to us and can inform us.

Was wondering though, in your forecast model, how much of the warm salty water from the 'Atlantic layer' of the Arctic Ocean did the storm mix in or bring to the surface?

How much of this warm water was from Ekman pumping? How much from wave action?

How much ice will this be melting over the coming days and weeks?

How did you calibrate your model for these effects? How big are the uncertainties in the calibration? In the modelling of the storm?
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on August 20, 2016, 12:55:14 AM
all current models are based on past data and experience and while i'm not sayin' it has to happen now (this year), sooner or later we shall see the events that make all models based on previous years appear obsolete, not to say misleading.

of course it's a legit approach while my 2cts are a prediction albeit i'm as close to 100% positive it will be that ways, as one can be :-) let's see.

that said i always did and still vote for a second place, provided that there will be no special events in mid september that will turn things once more upside down like so many times before. after all it depends on the weather while the conditions are set.
Title: Re: 2016 sea ice area and extent data
Post by: Tealight on August 20, 2016, 03:04:59 PM
Tealight, I appreciate you doing the model - and also others who do similar. It's a service to us and can inform us.

Was wondering though, in your forecast model, how much of the warm salty water from the 'Atlantic layer' of the Arctic Ocean did the storm mix in or bring to the surface?

How much of this warm water was from Ekman pumping? How much from wave action?

How much ice will this be melting over the coming days and weeks?

How did you calibrate your model for these effects? How big are the uncertainties in the calibration? In the modelling of the storm?

I didn't model any of these effects. My forecast model only calculates the aborbed solar energy and assumes perfect energy transfer from open water to ice. The last storm helped to make this reality but we are still at +1SD so there is more melt potential left.

Storms mostly increase the energy transfer between ocean-ice and (ocean-ice)-Atmosphere, but they don't add any energy to the system. The atmosphere is already sucking energy out of the ocean and as the days go by it will become more and more. Once all melt potential is gone new ice has to form. It is a simple energy input-output equation.

I posted more model details on the Developers corner:
http://forum.arctic-sea-ice.net/index.php/topic,1575.0.html (http://forum.arctic-sea-ice.net/index.php/topic,1575.0.html)

Quote from: magnamentis
all current models are based on past data and experience and while i'm not sayin' it has to happen now (this year), sooner or later we shall see the events that make all models based on previous years appear obsolete, not to say misleading.
magnamentis, your statement is more misleading than any model can be.

Models are not based on past data. They are made to simulate physics that fit past or future data. In other words data is the result and not the source.

As long as a model simulates reality well enough to satisfy the consumer then no one will change anything. If model predictions suddenly fall outside the desired accuracy range then a model developer will improve the model e.g. add a new variable or increase resolution. It will however never become obsolete.
Title: Re: 2016 sea ice area and extent data
Post by: Nick_Naylor on August 20, 2016, 03:29:32 PM
Storms mostly increase the energy transfer between ocean-ice and (ocean-ice)-Atmosphere, but they don't add any energy to the system. The atmosphere is already sucking energy out of the ocean and as the days go by it will become more and more.

Are you certain about this?

My uninformed sense is that storms can pull energy from warmer regions into the Arctic and deposit it there by condensation, convection and mechanical work (especially now that there are many polynyas where waves can form). I am open to being contradicted though  ???
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 20, 2016, 05:28:37 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Fri 2016.6274  -74.5  3.260544  +73.9 14.385759    -0.6 17.646303
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204209  +98.8 14.524028   +74.1 17.728237
Mon 2016.6356  -31.9  3.172290 +210.4 14.734400  +178.5 17.906690


CAB decline was -23k, Hudson increased by +16k.

Shadow NSIDC extent is now 5.1862 dropping -22.0k. CAB (-33k) and ESS (-20k) declined but Hudson increased (actually doubled its extent) by +41k.

The progress is visualized in the attached delta map.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 20, 2016, 05:56:58 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Fri 2016.6274  -74.5  3.260544  +73.9 14.385759    -0.6 17.646303
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204209  +98.8 14.524028   +74.1 17.728237
Mon 2016.6356  -31.9  3.172290 +210.4 14.734400  +178.5 17.906690


The effects of GAC 2016--or is that ARAC 2016?--continue to not be reflected in Wipneus's shadow area numbers; that's now three second consecutive below-average drops in area, as 2012 further widens its already large lead. Having said that, 2016 would still finish in 7th place overall were the melt season to end today. IOW, we're creeping up. Here's the updated a list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 79k
5th: 2010: 101k
4th: 2008: 169k
3rd: 2007: 253k
2nd: 2011: 268k
1st: 2012: 939k
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on August 20, 2016, 06:11:48 PM
Storms mostly increase the energy transfer between ocean-ice and (ocean-ice)-Atmosphere, but they don't add any energy to the system. The atmosphere is already sucking energy out of the ocean and as the days go by it will become more and more.

Are you certain about this?

My uninformed sense is that storms can pull energy from warmer regions into the Arctic and deposit it there by condensation, convection and mechanical work (especially now that there are many polynyas where waves can form). I am open to being contradicted though  ???
It's the total energy budget in question here, Nick.  While weather will bring heat north, as insolation drops, the best that imported heat can do is balance out the heat being lost out of the top of the atmosphere.   That's what we saw last winter - it doesn't put heat into the ice or water, it slows movement out of the water, so more can go into the ice.

The energy in the atmosphere is dwarfed by that in the Arctic ocean; the latent heat of crystallization in the top 1 meter of ocean if released to the atmosphere all at once would heat it to near boiling.  The only things keeping the ice around are the fact that ~200 Watts/M2 (Neat outgoing longwave radiation map: http://cimss.ssec.wisc.edu/wxwise/gifs/LWALL8.GIF (http://cimss.ssec.wisc.edu/wxwise/gifs/LWALL8.GIF)) is leaving the top of the atmosphere every second, and that halo and thermoclines keep most of that heat isolated from the ice.

In view of this, the heat brought at this time of year from further south by weather is a side show.  What's important (and dangerous) is how the storms are redistributing the heat that's already here.
Title: Re: 2016 sea ice area and extent data
Post by: Iceismylife on August 20, 2016, 07:09:29 PM
...
Storms mostly increase the energy transfer between ocean-ice and (ocean-ice)-Atmosphere, but they don't add any energy to the system. The atmosphere is already sucking energy out of the ocean and as the days go by it will become more and more. Once all melt potential is gone new ice has to form. It is a simple energy input-output equation.
 ...
Your model assumes no heat transfer from lower layers to upper layers in the water column.  Is that correct?

So how sever a storm is necessary to violate your assumption in a meaningful way?
Title: Re: 2016 sea ice area and extent data
Post by: Nick_Naylor on August 20, 2016, 11:09:01 PM
It's the total energy budget in question here, Nick.  While weather will bring heat north, as insolation drops, the best that imported heat can do is balance out the heat being lost out of the top of the atmosphere.

OK - so you're saying the storm does transfer energy to the Arctic system from the South, but not enough at this time of year to move net energy balance of the Arctic from negative to positive, and not enough to materially affect the ice. Is that correct?
Title: Re: 2016 sea ice area and extent data
Post by: jdallen on August 21, 2016, 12:21:37 AM
It's the total energy budget in question here, Nick.  While weather will bring heat north, as insolation drops, the best that imported heat can do is balance out the heat being lost out of the top of the atmosphere.

OK - so you're saying the storm does transfer energy to the Arctic system from the South, but not enough at this time of year to move net energy balance of the Arctic from negative to positive, and not enough to materially affect the ice. Is that correct?
Yes, you've pretty well summarized it.  The heat the storm applies to the ice is already there.
Title: Re: 2016 sea ice area and extent data
Post by: Tealight on August 21, 2016, 01:41:33 AM
...
Storms mostly increase the energy transfer between ocean-ice and (ocean-ice)-Atmosphere, but they don't add any energy to the system. The atmosphere is already sucking energy out of the ocean and as the days go by it will become more and more. Once all melt potential is gone new ice has to form. It is a simple energy input-output equation.
 ...
Your model assumes no heat transfer from lower layers to upper layers in the water column.  Is that correct?

So how sever a storm is necessary to violate your assumption in a meaningful way?

It's the total energy budget in question here, Nick.  While weather will bring heat north, as insolation drops, the best that imported heat can do is balance out the heat being lost out of the top of the atmosphere.

OK - so you're saying the storm does transfer energy to the Arctic system from the South, but not enough at this time of year to move net energy balance of the Arctic from negative to positive, and not enough to materially affect the ice. Is that correct?

The problems with storms is that they never affect the whole arctic. They have maybe a radius of 500-1000km where waves, ekman pumping and heat from the south will significantly impact melting, but the Arctic basin stretches over an area of roughly 3300*2800km. A storm on the Atlantic side can't prevent freezing on the pacific side and vice versa. Usually the other side of the Arctic experiences cooler than average conditons because it has cold winds from the north.

Edit: A SuperTyphoon(2200km diameter) is still not big enough to cover the entire Arctic.
(https://upload.wikimedia.org/wikipedia/commons/4/4e/Typhoonsizes.jpg)


Title: Re: 2016 sea ice area and extent data
Post by: Nick_Naylor on August 21, 2016, 03:05:42 AM
Regardless of it's physical size, a storm can enter the Arctic with considerable strength - i.e., energy - and the dissipate while over the rubble, effectively depositing that energy there. If the magnitude of that energy is irrelevant to melting ice directly, that's another matter.
Title: Re: 2016 sea ice area and extent data
Post by: Crocodile23 on August 21, 2016, 01:37:55 PM

The problems with storms is that they never affect the whole arctic. They have maybe a radius of 500-1000km where waves, ekman pumping and heat from the south will significantly impact melting, but the Arctic basin stretches over an area of roughly 3300*2800km. A storm on the Atlantic side can't prevent freezing on the pacific side and vice versa. Usually the other side of the Arctic experiences cooler than average conditons because it has cold winds from the north.

Edit: A SuperTyphoon(2200km diameter) is still not big enough to cover the entire Arctic.
(https://upload.wikimedia.org/wikipedia/commons/4/4e/Typhoonsizes.jpg)

 Actually this is a false impression that most people have, due to different map projections and because of the fact that most used are not authalic(equal area) projections, there is the very strong effect of high latitudes to appear having MUCH larger areas from the reality.

E.g here is how USA would appear if it was transferred to the arctic:
(https://s5.postimg.io/6s71y43hz/vnbvn67868768.png)

(from here: http://thetruesize.com/#/ (http://thetruesize.com/#/) )
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on August 21, 2016, 03:59:05 PM
Update for the week to August 20th

The current 5 day trailing average is on 5,186,000km2 while the 1 day extent is at 5,022,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,855,000km2, an increase from -1,723,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at +212,000km2, a decrease from +229,000km2 last week. We're currently 3rd lowest on record, the same as last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2Fy6JCzEo.png&hash=b199d634dc1bf2a58314acf272eeb397)

The average daily change over the last 7 days was -72.5k/day, compared to the long term average of -53.0k/day, and the 07, 11 and 12 average of -70.1k/day.
The average long term change over the next week is -44.4k/day, with the 07, 11, and 12 average being -60.1k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FYD3MTxB.png&hash=802c08577f2bd780accb14c538810f89)

The extent loss so far this August is the 5th largest on record. To achieve the largest monthly loss, a drop of at least 99.1k/day is required (requiring ~103.1k/day with with single day values), while the smallest loss requires an increase of at least 40.2k/day (+67.4k/day with single day values) and an average loss requires a drop of 8.3k/day (increase of 8.1k/day with single day values).

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FzjSSoGl.png&hash=09c2366fdbc75d340c1c3f5316841c5b)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on August 21, 2016, 04:19:37 PM
Using single day NSIDC extent values, 2016 has now dropped below the minima of every year up to and including 2006, as well and 2009 and 2013. It is also within 35k of 2014.

With the 5 day trailing average, 2016 has now dropped below the minima of every year up to and including 2006, and is just 66.2k off 2009.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FHrIzkwW.png&hash=43d96240d5aace285a3f6ab28ae21d46)

...Diff....... No of Years.. Percentage
Below 0........ 28............75.7%
0-100k.......... 1.............2.7%
100-250k....... 2.............5.4%
250-500k....... 0.............0.0%
500-1000k..... 4.............10.8%
>1000k......... 2.............5.4%
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 21, 2016, 05:02:45 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204209  +98.8 14.524028   +74.1 17.728237
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.5  3.128512  +84.5 14.818940   +41.0 17.947452


CAB: -23k and Hudson +16k.

Shadow NSIDC extent is now 5.0224 a drop of -163.8k. CAB (-68k), CAA (-32k) and Hudson (-27) took care of this.

Have a look at the attached delta map for some more details.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 21, 2016, 05:34:48 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204209  +98.8 14.524028   +74.1 17.728237
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.5  3.128512  +84.5 14.818940   +41.0 17.947452


2016 would finish up in 7th place overall were the melt season to end today. The updated list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 35k
5th: 2010: 57k
4th: 2008: 125k
3rd: 2007: 210k
2nd: 2011: 224k
1st: 2012: 895k
Title: Re: 2016 sea ice area and extent data
Post by: Shared Humanity on August 21, 2016, 08:12:46 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204209  +98.8 14.524028   +74.1 17.728237
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.5  3.128512  +84.5 14.818940   +41.0 17.947452



2016 would finish up in 7th place overall were the melt season to end today. The updated list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 35k
5th: 2010: 57k
4th: 2008: 125k
3rd: 2007: 210k
2nd: 2011: 224k
1st: 2012: 895k

Looks like a lock on 4th place with 2nd still a very strong possibility.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 21, 2016, 08:36:40 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204209  +98.8 14.524028   +74.1 17.728237
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.5  3.128512  +84.5 14.818940   +41.0 17.947452



2016 would finish up in 7th place overall were the melt season to end today. The updated list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 35k
5th: 2010: 57k
4th: 2008: 125k
3rd: 2007: 210k
2nd: 2011: 224k
1st: 2012: 895k

Looks like a lock on 4th place with 2nd still a very strong possibility.

At this point, I will--possibly foolishly--slide all my chips over to 2nd place. My "logic": over the last ten years, the average drop from today through minimum has been 470k, with nine of those ten years seeing enough additional area loss to give 2016 the silver (2007 was the lone holdout; a repeat of that year's remaining decrease would leave 2016 in 4th.)

But, as always, we will see...
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on August 21, 2016, 10:25:07 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.6301  -31.7  3.228863  +39.5 14.425276    +7.8 17.654139
Sun 2016.6329  -24.7  3.204209  +98.8 14.524028   +74.1 17.728237
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.5  3.128512  +84.5 14.818940   +41.0 17.947452



2016 would finish up in 7th place overall were the melt season to end today. The updated list of the additional area 2016 needs to lose in order to reach each of the remaining ranks:

6th: 2015: 35k
5th: 2010: 57k
4th: 2008: 125k
3rd: 2007: 210k
2nd: 2011: 224k
1st: 2012: 895k

Looks like a lock on 4th place with 2nd still a very strong possibility.

At this point, I will--possibly foolishly--slide all my chips over to 2nd place. My "logic": over the last ten years, the average drop from today through minimum has been 470k, with nine of those ten years seeing enough additional area loss to give 2016 the silver (2007 was the lone holdout; a repeat of that year's remaining decrease would leave 2016 in 4th.)

But, as always, we will see...

I strongly agree that 2nd is a given (though I am still thinking we hit first).

Interesting tidbit re: continued losses of 470K KM2 between now and minimum...

Given how horrible the state of the ice is this year vs previous years at this time, I would think it is an indicator that we will lose much more than 470K KM2.

If we avg losses of -30K/day for another month, we beat 2012... not a high bar to set, esp given forecast for continued cyclones, and the fact that we have much less high concentration/structurally intact ice than '12.
Title: Re: 2016 sea ice area and extent data
Post by: werther on August 21, 2016, 10:44:28 PM
The flaw in your assumption, bbr, is 1. that a lot of scattered FYI in  the 'Laptev arm', is not in an environment that supports a lot of melt and 2. all that dispersed ice in the Bering sector is remaining MYI, which is quite resistant.
I am sure the quality of the pack is worst ever, but I doubt the rest of this melting season will produce more than 1Mkm2 of further losses.
I still hold my position in the poll on the 3.75-4Mkm2 box, but I think it will be a very narrow hit (3.98 ?).
Title: Re: 2016 sea ice area and extent data
Post by: Tigertown on August 21, 2016, 10:52:26 PM
It will really surpise me if this year does not take over first place minimal area wise. The SIE though, is being stubborn this year. Seaicesailor pointed out on the other thread that we are about to start loosing some chunks of MYI, which could really be setting up an even worse year for 2017.
Title: Re: 2016 sea ice area and extent data
Post by: werther on August 21, 2016, 11:04:25 PM
Oh sure, SIA is a different matter. The one metric that will be really interesting is PIOMAS volume at minimum.
Title: Re: 2016 sea ice area and extent data
Post by: icefisher on August 22, 2016, 01:54:07 AM
I agree Werther.  Volume will indeed be very interesting.  Normally, volume continues to decline until late in September or early October but with all the venting from the fractured CAB, volume, extent and area, may all bottom out much earlier than anticipated.  My original dartboard volume guess of 4800 may turn out a little high.  More importantly is the distribution of volume by ice age.  Will the percentage of volume attributable to MYI go up or down compared to trend?
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 22, 2016, 01:01:06 PM
It will really surpise me if this year does not take over first place minimal area wise.

Prepare to be surprised, then; it's not going to happen. To wit:

--First place for SIA is 895k away.

--No year in the past quarter century has lost that much area from now through minimum. The average over that period: 459k

--There are roughly 20-25 days left in the melt season (the long-term average is 21 days).

--First place would mean a sustained daily loss of 30k-36k.

So, again: not going to happen. There'll be no area record this summer...
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 22, 2016, 04:29:20 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sun 2016.6329  -24.7  3.204209  +98.8 14.524028   +74.1 17.728237
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.1  3.128940  +84.9 14.819282   +41.8 17.948222
Wed 2016.6411  +19.8  3.148739  +99.0 14.918255  +118.8 18.066994


No significant regional area changes, except "Lakes" that increased +29k. Yes, we all know how much ice there is a.t.m. on the Great Lakes.

Shadow NSIDC extent is now 5.0214  dropping  -1.0k. Here we have increases in the CAB (+24k), and CAA (+16k). Declines are found in Baffin (-24k) and Kara (-20k).

In the attached delta map, the quietness in the Arctic Basin can be noted.
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on August 23, 2016, 07:58:17 AM
The small declines in area and extent from the past couple of days do surprise me.
With the significantly dispersed ice pack (with arms into the ESS and the Laptev) and the resulting low overall ice concentration, I would have expected some significant drops.
Maybe in the days to come ?
Title: Re: 2016 sea ice area and extent data
Post by: ra3000 on August 23, 2016, 10:33:08 AM
The concentration is very low at some points even within the boundaries of the central Arctic.
Nonetheless, we don't have to forget that we are approaching to the dates of the upsidedowns before the refreezing season begins.
The thing is, that even if the trend is to have less extent sea ice (not only in summers but also recently during the last winters), having a low extent may lead to a early stall.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 23, 2016, 07:08:14 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.1  3.128940  +84.9 14.819282   +41.8 17.948222
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +25.0  3.175113  -36.4 14.881868   -11.4 18.056981


The only region that can be mentioned is Kara (+15k).

Shadow NSIDC extent is now 5.1012 an uptick of +79.8k. Kara leads with +43k, followed by the CAA (+28k) and CAB (+19k).

The quietness in the Arctic can be judged with the attached delta map.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 24, 2016, 12:40:01 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.1  3.128940  +84.9 14.819282   +41.8 17.948222
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +25.0  3.175113  -36.4 14.881868   -11.4 18.056981


FWIW, one or more days of increased area isn't a rarity around this time. Just last year, we saw four consecutive days of area growth that lead to 150k of net growth--followed by 16 days of ice decrease in which an additional 523k disappeared. 2012 had a four-day span that saw two large increases and just 15k of area loss, and that was followed by 493k before minimum. And one more: 2007 went through an 11-day span in which area rose by 103k, and that was followed by an 8-day drop to minimum of 257k.
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on August 24, 2016, 03:44:18 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Mon 2016.6356  -32.2  3.172037 +210.4 14.734391  +178.2 17.906428
Tue 2016.6384  -43.1  3.128940  +84.9 14.819282   +41.8 17.948222
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +25.0  3.175113  -36.4 14.881868   -11.4 18.056981


FWIW, one or more days of increased area isn't a rarity around this time. Just last year, we saw four consecutive days of area growth that lead to 150k of net growth--followed by 16 days of ice decrease in which an additional 523k disappeared. 2012 had a four-day span that saw two large increases and just 15k of area loss, and that was followed by 493k before minimum. And one more: 2007 went through an 11-day span in which area rose by 103k, and that was followed by an 8-day drop to minimum of 257k.
The problem is that area is not increasing. The "increases" are clouds or interference of whatever type. Clearly, the Kara is completely ice-free and 15K KM2 of ice did not spontaneously appear along its shorelines. It is just noise and the gains should not be interpreted as legitimate (at least not until we hit minimum).
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 24, 2016, 04:12:32 PM
The problem is that area is not increasing. The "increases" are clouds or interference of whatever type. Clearly, the Kara is completely ice-free and 15K KM2 of ice did not spontaneously appear along its shorelines. It is just noise and the gains should not be interpreted as legitimate (at least not until we hit minimum).

The thing is, scientists use data. They don't simply dismiss out of hand those they don't like because numbers disagree with what they think or feel they should be. At the end of the season, we can't look at any of the metrics and say, "I don't care what PIOMAS, or IJIS, or NSIDC, or anyone else says; they were all just measuring 'clouds or interference', so the official numbers 'should not be interpreted as legitimate'."
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 24, 2016, 04:43:33 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Tue 2016.6384  -43.1  3.128940  +84.9 14.819282   +41.8 17.948222
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +24.7  3.174887  -36.3 14.881905   -11.6 18.056792
Fri 2016.6466  -86.3  3.088544 -127.7 14.754198  -214.0 17.842742


Regional declines in Laptev (-29k) and CAA (-17k). Also ice area on "Lakes" measured -21k less.

Shadow NSIDC extent is now 4.9823 dropping -118.9k. Regional extent declines in Laptev (-54k), CAA (-46k), Hudson (-22k) and Kara (-20k). The CAB increased by +18k.

The attached delta map shows what the numbers cannot.
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on August 24, 2016, 05:10:26 PM
The problem is that area is not increasing. The "increases" are clouds or interference of whatever type. Clearly, the Kara is completely ice-free and 15K KM2 of ice did not spontaneously appear along its shorelines. It is just noise and the gains should not be interpreted as legitimate (at least not until we hit minimum).

The thing is, scientists use data. They don't simply dismiss out of hand those they don't like because numbers disagree with what they think or feel they should be. At the end of the season, we can't look at any of the metrics and say, "I don't care what PIOMAS, or IJIS, or NSIDC, or anyone else says; they were all just measuring 'clouds or interference', so the official numbers 'should not be interpreted as legitimate'."
I am not saying data is bad, I am saying this data is corrupted and somewhat inaccurate. While it certainly has value, that value is lessened when people misinterpret clouds as gains.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 24, 2016, 05:27:04 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Tue 2016.6384  -43.1  3.128940  +84.9 14.819282   +41.8 17.948222
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +24.7  3.174887  -36.3 14.881905   -11.6 18.056792
Fri 2016.6466  -86.3  3.088544 -127.7 14.754198  -214.0 17.842742


That puts 2016 ahead of 2015 and into 6th place overall. Here's a list of the years in 1st through 5th place, along with how much more ice needs to disappear for 2016 to move into each of the remaining ranks:

5th: 2010: 17k
4th: 2008: 85k
3rd: 2007: 170k
2nd: 2011: 184k
1st: 2012: 855k

I am not saying data is bad, I am saying this data is corrupted and somewhat inaccurate.

So data that are "corrupted" and "inaccurate" aren't necessarily "bad"? Lemme check my dictionary on that one... ;-)
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on August 24, 2016, 05:32:36 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Tue 2016.6384  -43.1  3.128940  +84.9 14.819282   +41.8 17.948222
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +24.7  3.174887  -36.3 14.881905   -11.6 18.056792
Fri 2016.6466  -86.3  3.088544 -127.7 14.754198  -214.0 17.842742


That puts 2016 ahead of 2015 and into 6th place overall. Here's a list of the years in 1st through 5th place, along with how much more ice needs to disappear for 2016 to move into each of the remaining ranks:

5th: 2010: 17k
4th: 2008: 85k
3rd: 2007: 170k
2nd: 2011: 184k
1st: 2012: 855k

I am not saying data is bad, I am saying this data is corrupted and somewhat inaccurate.

So data that are "corrupted" and "inaccurate" aren't necessarily "bad"? Lemme check my dictionary on that one... ;-)

...did you read what I said?
Title: Re: 2016 sea ice area and extent data
Post by: RoxTheGeologist on August 24, 2016, 06:25:19 PM

There is noise in data.

https://en.wikipedia.org/wiki/Colors_of_noise

It doesn't make the data 'bad' and you will note that noise can add to or subtract from the underlying signal. Many people have pointed out that looking at day to day data (whether high or low) and making assumptions about the trend is a rather pointless endeavor. Using a moving average (is it Jim who provides that?) lessens the impact of noise.

If there is bias in the data from noise, one assumes that the same potential artifacts are in the data from previous years and have been reported consistently for those years.  It would be an enormously easy way to discredit the information that is carefully gathered if you say, "Well this year we are doing 'this'" without a very clearly defined model and data to show why we are doing 'this'. Then one goes back and changes the model for all previous years so that comparisons can still be made.



Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on August 25, 2016, 07:28:09 AM
There is noise in data.

Thank you Rox.
This noise is clear in Wipneus' latest posts :
Aug 21: Shadow NSIDC extent is now 5.0224 a drop of -163.8k.
Aug 22: Shadow NSIDC extent is now 5.0214  dropping  -1.0k.
Aug 23: Shadow NSIDC extent is now 5.1012 an uptick of +79.8k.
Aug 24: Shadow NSIDC extent is now 4.9823 dropping -118.9k.

Maybe this is why IJIS and NSIDC use multiple-day averages.

As Neven said, this is 'the slowest horse race in the world'.
Let us not get over excited about single day changes.
Title: Re: 2016 sea ice area and extent data
Post by: Richard Rathbone on August 25, 2016, 03:24:04 PM
There is noise in data.

Thank you Rox.
This noise is clear in Wipneus' latest posts :
Aug 21: Shadow NSIDC extent is now 5.0224 a drop of -163.8k.
Aug 22: Shadow NSIDC extent is now 5.0214  dropping  -1.0k.
Aug 23: Shadow NSIDC extent is now 5.1012 an uptick of +79.8k.
Aug 24: Shadow NSIDC extent is now 4.9823 dropping -118.9k.

Maybe this is why IJIS and NSIDC use multiple-day averages.

As Neven said, this is 'the slowest horse race in the world'.
Let us not get over excited about single day changes.

NSIDC specifically caution against using daily values for comparison purposes and normally use monthly ones in their analyses.
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on August 25, 2016, 04:40:42 PM
Single day NSIDC extent down 42k, taking us back to 3rd lowest for the time of year.

Both the 5 day trailing average and the single day values are below all previous minima bar 2007, 08, 10, 11, 12 and 15.
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 25, 2016, 04:44:18 PM
Some here seem to be missing my point; I'll have to chalk that up to a failure of mine to communicate properly. So one more time:

Yes, daily numbers can be noisy. They can be inaccurate. And, if one wishes, they can be discounted. HOWEVER--for purposes of declaring record values, those numbers are literally all we have. More importantly, they're all we've ever had. Now, an intellectually honest person will discount all those daily numbers if they're going to discount any; they won't declare only those numbers that validate their (sometimes) overzealous forecasts as true and correct, and dismiss as "inaccurate" and "corrupt" any numbers that show otherwise. Doing so is called "cherrypicking", of course, and it's --rightly--frowned upon in scientific circles. So, either we reject all minimum/maximum sea ice records based on all daily numbers being suspect, or we reject none, acknowledging that they may or may not precisely reflect reality, but that biases have been accounted for.

Which will it be?

(As a recap, this particular thread began  a few days back when I noted that Wipneus's shadow area numbers had gone up for two consecutive days, and one member responded that area had NOT gone up, based on the fact that Wipneus's numbers for those two days only were corrupt and inaccurate.)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 25, 2016, 04:54:52 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +24.7  3.174887  -36.3 14.881905   -11.6 18.056792
Fri 2016.6466  -86.3  3.088586 -129.1 14.752838  -215.4 17.841424
Sat 2016.6493 -170.0  2.918591  +26.1 14.778897  -143.9 17.697488


Most of this in the CAB: -146k.

Shadow NSIDC extent is now 4.9397 dropping -42.6k. CAB declined -31k, CAA increased +32k. Small changes elsewhere.

The attached daily delta map has put some colors in the CAB, missing in the last few days.
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on August 25, 2016, 05:23:44 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +24.7  3.174887  -36.3 14.881905   -11.6 18.056792
Fri 2016.6466  -86.3  3.088586 -129.1 14.752838  -215.4 17.841424
Sat 2016.6493 -170.0  2.918591  +26.1 14.778897  -143.9 17.697488


Most of this in the CAB: -146k.

Shadow NSIDC extent is now 4.9397 dropping -42.6k. CAB declined -31k, CAA increased +32k. Small changes elsewhere.

The attached daily delta map has put some colors in the CAB, missing in the last few days.
Given the false gains this shows despite still attaining a loss of 170K KM2, I think we still have several century++ losses remaining... tomorrow we should clear the #2 spot leaving only 2012 ahead. I don't think it'll stay ahead...
Title: Re: 2016 sea ice area and extent data
Post by: Buddy on August 25, 2016, 07:51:11 PM
Quote
Most of this in the CAB: -146k.

Shadow NSIDC extent is now 4.9397 dropping -42.6k. CAB declined -31k, CAA increased +32k. Small changes elsewhere.

Will be interesting to see where we are in a week or two.....  Mr. Ice Sheet is not looking good these days :(
Title: Re: 2016 sea ice area and extent data
Post by: magnamentis on August 25, 2016, 08:12:14 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Wed 2016.6411  +21.2  3.150159  +99.0 14.918244  +120.2 18.068403
Thu 2016.6438  +24.7  3.174887  -36.3 14.881905   -11.6 18.056792
Fri 2016.6466  -86.3  3.088586 -129.1 14.752838  -215.4 17.841424
Sat 2016.6493 -170.0  2.918591  +26.1 14.778897  -143.9 17.697488


Most of this in the CAB: -146k.

Shadow NSIDC extent is now 4.9397 dropping -42.6k. CAB declined -31k, CAA increased +32k. Small changes elsewhere.

The attached daily delta map has put some colors in the CAB, missing in the last few days.
Given the false gains this shows despite still attaining a loss of 170K KM2, I think we still have several century++ losses remaining... tomorrow we should clear the #2 spot leaving only 2012 ahead. I don't think it'll stay ahead...

true that, sure you have seen my post in the "melting season thread, the one about the "Ax" as well as the one with double century drops, the first is already showing and the second was close this time :-)

<Removed last sentence. Stop breeding ego conflicts, and watch the ice. Last warning. N.>
Title: Re: 2016 sea ice area and extent data
Post by: Neven on August 25, 2016, 09:27:49 PM
It will be interesting to see whether this century break is followed by others right away, or whether we get some 'false' gains first. With the current weather forecast I do expect CT SIA to go down some more. I'm not sure if it can still catch 2012, as 685K is quite a lot of SIA at this point, but the forecast is pretty insane.

Such a Dipole in June or July... I don't even want to think about how the ice would look right now.
Title: Re: 2016 sea ice area and extent data
Post by: Random_Weather on August 25, 2016, 09:34:31 PM
@ Neven

I dont know, i think now where the ice is thin and more open, it becomes more effctive then in June/july, because of more wave forcing and effective energy imput (because of the clouds and warm air).

Its the same thing with the GAC in 2012, this in June would not destroyed so many Extent as it has.

Edit:

But would agree, it should not be enough to beat Area from 2012, but could give the chance to fill the place between 2012 and other years
Title: Re: 2016 sea ice area and extent data
Post by: Neven on August 25, 2016, 09:46:55 PM
@ Neven

I dont know, i think now where the ice is thin and more open, it becomes more effctive then in June/july, because of more wave forcing and effective energy imput (because of the clouds and warm air).

Its the same thing with the GAC in 2012, this in June would not destroyed so many Extent as it has.

True, but it would cause an enormous amount of preconditioning that would make itself felt in August.

The sun is much lower now, and the cold is coming. The dispersed ice on the periphery (especially the Wrangel arms) would probably be a goner anyway after the GAC. This is going to be a compaction event. Compaction towards the end of the melting season makes a real difference.

Quote
But would agree, it should not be enough to beat Area from 2012, but could give the chance to fill the place between 2012 and other years

Yes, this is as good as certain for CT SIA. Already third lowest now, just 14K needed to breeze past 2011.
Title: Re: 2016 sea ice area and extent data
Post by: AmbiValent on August 25, 2016, 09:47:24 PM
Area is now below 2007 minimum and barely above 2011 minimum. Second place is almost guaranteed.
Title: Re: 2016 sea ice area and extent data
Post by: Random_Weather on August 25, 2016, 10:07:31 PM

Quote
True, but it would cause an enormous amount of preconditioning that would make itself felt in August.

Thats true

Quote
The sun is much lower now, and the cold is coming. The dispersed ice on the periphery (especially the Wrangel arms) would probably be a goner anyway after the GAC. This is going to be a compaction event. Compaction towards the end of the melting season makes a real difference.

Yes, but also albedo is higher in June/July, so there is much pot. energy lost direct by albedo, but now, sun is low but not the point, the much more relevant point is, clouds, which gives long-wave energy surface downward, is much less the solar downward in July/june but is more effective now, because the concentration and thickniss is low, mobility of ice is also stronger and because of much summer divergence, it has now very much pot. to compact the ice.



Quote
Yes, this is as good as certain for CT SIA. Already third lowest now, just 14K needed to breeze past 2011.

y, should happen with data from tomorrow
Title: Re: 2016 sea ice area and extent data
Post by: Michael Hauber on August 26, 2016, 01:37:17 AM
Such a Dipole in June or July... I don't even want to think about how the ice would look right now.

Perhaps we could think about how all the open water would look like right now.
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on August 26, 2016, 01:55:22 AM
@ Neven

I dont know, i think now where the ice is thin and more open, it becomes more effctive then in June/july, because of more wave forcing and effective energy imput (because of the clouds and warm air).

Its the same thing with the GAC in 2012, this in June would not destroyed so many Extent as it has.

True, but it would cause an enormous amount of preconditioning that would make itself felt in August.

The sun is much lower now, and the cold is coming. The dispersed ice on the periphery (especially the Wrangel arms) would probably be a goner anyway after the GAC. This is going to be a compaction event. Compaction towards the end of the melting season makes a real difference.

Quote
But would agree, it should not be enough to beat Area from 2012, but could give the chance to fill the place between 2012 and other years

Yes, this is as good as certain for CT SIA. Already third lowest now, just 14K needed to breeze past 2011.
I've bolded the chief problem we've seen so far this year. In fact, the ice has only recently barely started compacting in the triangle N of Greenland & the CAA. Elsewhere, where it would normally compact, the amount of open water between floes has instead caused it to simply drift, which is *very bad* for the ice.

If you loop MODIS you can see this happening along the edge of the stable triangle, the boundaries of which continue retreating towards the CAA...

The big remaining question is whether the wedge of multi-yr ice now rapidly heading into the Atlantic will be melted out by the coming activity over the Kara or not. I think that is what makes the difference between sub-2M KM2 and 1M (which, I know you ppl may think is crazy, I think is still a possibility).
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on August 26, 2016, 06:22:08 AM
@ Neven

I dont know, i think now where the ice is thin and more open, it becomes more effctive then in June/july, because of more wave forcing and effective energy imput (because of the clouds and warm air).

Its the same thing with the GAC in 2012, this in June would not destroyed so many Extent as it has.

True, but it would cause an enormous amount of preconditioning that would make itself felt in August.

The sun is much lower now, and the cold is coming. The dispersed ice on the periphery (especially the Wrangel arms) would probably be a goner anyway after the GAC. This is going to be a compaction event. Compaction towards the end of the melting season makes a real difference.

Quote
But would agree, it should not be enough to beat Area from 2012, but could give the chance to fill the place between 2012 and other years

Yes, this is as good as certain for CT SIA. Already third lowest now, just 14K needed to breeze past 2011.
I've bolded the chief problem we've seen so far this year. In fact, the ice has only recently barely started compacting in the triangle N of Greenland & the CAA. Elsewhere, where it would normally compact, the amount of open water between floes has instead caused it to simply drift, which is *very bad* for the ice.

I agree. There is not much potential for "compaction" in the Wrangel Island arms. Ice will simply drift around (in still warming ocean water), and yes, that is bad for the ice.

Also, ice "concentration" is idiotically low right already, so much so that I cannot imagine that "area" would fall even further without some really SERIOUS decline in "extent" over the next couple of days.
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on August 26, 2016, 06:41:47 AM
I think that is what makes the difference between sub-2M KM2 and 1M (which, I know you ppl may think is crazy, I think is still a possibility).
Yes, I think sub-2M is crazy, and not a serious possibility.
1M is out of the question.
Title: Re: 2016 sea ice area and extent data
Post by: budmantis on August 26, 2016, 06:55:54 AM
I think that is what makes the difference between sub-2M KM2 and 1M (which, I know you ppl may think is crazy, I think is still a possibility).
Yes, I think sub-2M is crazy, and not a serious possibility.
1M is out of the question.

I have to agree with Rob on this. 2M isn't entirely out of the question but highly unlikely. In other words, it would take an event of such magnitude that it would trump any other event observed in the last ten or more years. Note: I do regret using the term "trump" but it seemed to be the best I could do at the moment.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 26, 2016, 09:25:59 AM

Quote
But would agree, it should not be enough to beat Area from 2012, but could give the chance to fill the place between 2012 and other years

Yes, this is as good as certain for CT SIA. Already third lowest now, just 14K needed to breeze past 2011.

It is good you mention it is CT Area, not simply Area. There are a number of reasons not to use CT-Area that I have discussed before.

"Area" calculated from the same NSIDC sea ice concentration using a less questionable method gives sometimes different rankings. For example at the moment 2016 is in second place firmly filling the gap between 2012 and other years:


Date      "NSIDC area"
2015-08-24 3.531752
2008-08-24 3.444459
2007-08-24 3.052184
2011-08-24 3.030930
2016-08-24 2.876135
2012-08-24 2.674178
 

(extracted from https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_nt_nrt_main.txt and https://sites.google.com/site/arctischepinguin/home/sea-ice-extent-area/data/nsidc_nt_final_main.txt.gz)
Title: Re: 2016 sea ice area and extent data
Post by: Nightvid Cole on August 26, 2016, 03:16:35 PM
Is this real (from ASIG page) ?
Title: Re: 2016 sea ice area and extent data
Post by: Nightvid Cole on August 26, 2016, 03:19:10 PM
If so:

https://www.youtube.com/watch?v=V0LV_bETEzs (https://www.youtube.com/watch?v=V0LV_bETEzs)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on August 26, 2016, 03:19:59 PM
Single day NSIDC extent down 90k, but also dropping behind 2011, so now 4th lowest for the time of year.
However, as 2007 and 2011 go went through a temporary stall over the next few days (followed by large losses again), a drop of anything over 20k in the next 2 days will take us to 2nd lowest for the time of year

With regard to previous minima, we are now just 260k and 302k off 2010 and 2008 minima respectively.
Title: Re: 2016 sea ice area and extent data
Post by: Nick_Naylor on August 26, 2016, 04:12:09 PM
Is this real (from ASIG page) ?

Sure it's real. It just shows what you can clearly see from satellite images: Extent has been hanging in there while area has fallen sharply, because the rubble is widely scattered.
The anomaly is most striking for the 3.125 km chart because that small cell size usually is fine enough so that cells with >15% concentration have significantly more than that on average. Not this year.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 26, 2016, 04:14:24 PM
Is this real (from ASIG page) ?

Yup, and it got worse today. Unusual low and late minimum, possibly record low and/or late (for the NSIDC compactness).
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 26, 2016, 04:21:58 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Thu 2016.6438  +24.7  3.174887  -36.3 14.881905   -11.6 18.056792
Fri 2016.6466  -86.3  3.088586 -129.1 14.752838  -215.4 17.841424
Sat 2016.6493 -170.0  2.918565  +56.9 14.809784  -113.1 17.728349
Sun 2016.6521 -109.9  2.808681  -39.9 14.769898  -149.8 17.578579


Most is in the CAB: -85k, also some decline of "lake ice" (-15k).

Shadow NSIDC extent is now 4.8498 dropping -88.7k. Responsible ar CAB (-45k), CAA (-32k) and ESS (-26k).

There is of course an attached delta map to tell you even more.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 26, 2016, 04:27:56 PM
Closer to 2012 than any other year.


Date      "NSIDC area"(*)
2015-08-25  3.519381
2008-08-25  3.292974
2011-08-25  3.095398
2007-08-25  3.056328
2016-08-25  2.776879
2012-08-25  2.615146
 

(*) Read my post about when Area is not CT-Area: http://forum.arctic-sea-ice.net/index.php/topic,1457.msg87761.html#msg87761 (http://forum.arctic-sea-ice.net/index.php/topic,1457.msg87761.html#msg87761)
Title: Re: 2016 sea ice area and extent data
Post by: Comradez on August 26, 2016, 06:36:34 PM
Well...2016 is in 2nd place now.  That was fast.

A couple more century breaks, and 2016 will be breathing down 2012's neck. 

I'm sad that the CT data set is not going to be officially tracked any more.  CT was probably where we were going to see the first sub <1 million reading, which would have raised awareness due to meeting many people's definition of "virtually ice-free arctic." 
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on August 26, 2016, 08:43:11 PM
With an official # at 2.8 despite all the clouds, I think the "real" number we would be able to see if IR was perfect would be just about where 2012 is right now... and I anticipate ongoing century drops as we continue pivoting between the sensors' confusion re: clouds and glimpses at the wreckage underneath.

The impending GAC is going to be a whole lot warmer than any we've previously seen, equally as important will be the area it effects, which will be pretty much the entire Arctic (and come D2-3, it will be helped by a second sub-980mb low over Kara!)

Lionrock delivers an impressive burst of Pacific heat immediately afterwards that flows up through Siberia, visible ~D7 on today's 12z EURO, which will further sustain bottom melt (and allow some continuation of top melt).

Given all the above, and the fact that the compaction at the moment is worse than ever before, we already have the momentum for the worst late-season drop in area on record, IMO. By this time 2012 was already solidifying its pitiful remnants into some sort of cohesive blob.... 2016 is not quite there as the impending storm will further reduce the "triangle of fortitude".
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on August 27, 2016, 08:01:50 AM
With an official # at 2.8 despite all the clouds, I think the "real" number we would be able to see if IR was perfect would be just about where 2012 is right now...

Instead of "IR", I assume that you mean SSMIS or AMSR2 ?
Title: Re: 2016 sea ice area and extent data
Post by: bbr2314 on August 27, 2016, 10:48:23 AM
With an official # at 2.8 despite all the clouds, I think the "real" number we would be able to see if IR was perfect would be just about where 2012 is right now...

Instead of "IR", I assume that you mean SSMIS or AMSR2 ?
Yes :)
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 27, 2016, 03:46:15 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Fri 2016.6466  -86.3  3.088586 -129.1 14.752838  -215.4 17.841424
Sat 2016.6493 -170.0  2.918565  +56.9 14.809784  -113.1 17.728349
Sun 2016.6521 -109.9  2.808624  -40.2 14.769597  -150.1 17.578221
Mon 2016.6548  -56.0  2.752629  +80.0 14.849575   +24.0 17.602204


Responsible are CAB (-44k) and Chukchi (-16k).

Shadow NSIDC extent is now 4.6910 -dropping 158.8k. CAB (-77k), Chukchi (-56k) and ESS (-31k) took the beatings.
2016 is now in second place, taking over 2011 and 2007.

There is an attached delta map where these beatings are painted red.
Title: Re: 2016 sea ice area and extent data
Post by: ktonine on August 27, 2016, 05:00:59 PM
Now, an intellectually honest person will discount all those daily numbers if they're going to discount any; they won't declare only those numbers that validate their (sometimes) overzealous forecasts as true and correct, and dismiss as "inaccurate" and "corrupt" any numbers that show otherwise. Doing so is called "cherrypicking", of course, and it's --rightly--frowned upon in scientific circles. So, either we reject all minimum/maximum sea ice records based on all daily numbers being suspect, or we reject none, acknowledging that they may or may not precisely reflect reality, but that biases have been accounted for.

No, biases have NOT been fully accounted for.  That's precisely why the uncertainties are so large.  And scientists are constantly discounting data from observations - it's a fundamental part of science.  It has little to do with 'cherry-picking' - just an adequate BS detector.  Even the scientists who collected the FTL neutrino data didn't believe it.  If data doesn't meet a common-sense test or match physical theory and no explanation can be found, THEN physical theory needs revision.  Usually an explanation can be found after further scrutiny.  Spencer & Christy's satellite data showing global *cooling* is another case in point.  The fact this may be the best we have or that it's a helluva scientific achievement to even be able to produce it does not mean you should trust the results beyond the uncertainties stated and even then show some skepticism.


(As a recap, this particular thread began  a few days back when I noted that Wipneus's shadow area numbers had gone up for two consecutive days, and one member responded that area had NOT gone up, based on the fact that Wipneus's numbers for those two days only were corrupt and inaccurate.)

It's worth noting that the three days following the uptick saw 365k in losses.  The gains were a mirage.  bbr's statement that you can't always trust daily numbers was nothing outlandish.  Anyone that follows these numbers knows it's true.  What was the point of criticizing it?

I hesitate to pollute this thread with this type of meta-analysis, but it's become less and less fun to read the comments when more and more I see nothing but harsh criticisms of others *opinions.* 
Title: Re: 2016 sea ice area and extent data
Post by: Iceismylife on August 27, 2016, 05:25:52 PM
...

 If data doesn't meet a common-sense test or match physical theory and no explanation can be found, THEN physical theory needs revision.

...
That is a mouthful.  I've seen something repeated several times that I lack a physics explanation for.
I hesitate to pollute this thread with this type of meta-analysis, but it's become less and less fun to read the comments when more and more I see nothing but harsh criticisms of others *opinions.*
There are nicer ways of dealing with "problems".
Title: Re: 2016 sea ice area and extent data
Post by: seaicesailor on August 27, 2016, 05:52:29 PM
Big big drops of extent fellows.
These must be accurate! They adhere well to the established theories around.
Title: Re: 2016 sea ice area and extent data
Post by: seaicesailor on August 27, 2016, 06:03:55 PM
The Atlantic front is amazing. Even some red, little blue, day after day. Greenland sea melting of ice import is not a tenth as fast. How long will this last?
Title: Re: 2016 sea ice area and extent data
Post by: Jim Pettit on August 27, 2016, 06:52:43 PM
Now, an intellectually honest person will discount all those daily numbers if they're going to discount any; they won't declare only those numbers that validate their (sometimes) overzealous forecasts as true and correct, and dismiss as "inaccurate" and "corrupt" any numbers that show otherwise. Doing so is called "cherrypicking", of course, and it's --rightly--frowned upon in scientific circles. So, either we reject all minimum/maximum sea ice records based on all daily numbers being suspect, or we reject none, acknowledging that they may or may not precisely reflect reality, but that biases have been accounted for.

No, biases have NOT been fully accounted for.  That's precisely why the uncertainties are so large.  And scientists are constantly discounting data from observations - it's a fundamental part of science.  It has little to do with 'cherry-picking' - just an adequate BS detector.  Even the scientists who collected the FTL neutrino data didn't believe it.  If data doesn't meet a common-sense test or match physical theory and no explanation can be found, THEN physical theory needs revision.  Usually an explanation can be found after further scrutiny.  Spencer & Christy's satellite data showing global *cooling* is another case in point.  The fact this may be the best we have or that it's a helluva scientific achievement to even be able to produce it does not mean you should trust the results beyond the uncertainties stated and even then show some skepticism.


(As a recap, this particular thread began  a few days back when I noted that Wipneus's shadow area numbers had gone up for two consecutive days, and one member responded that area had NOT gone up, based on the fact that Wipneus's numbers for those two days only were corrupt and inaccurate.)

It's worth noting that the three days following the uptick saw 365k in losses.  The gains were a mirage.  bbr's statement that you can't always trust daily numbers was nothing outlandish.  Anyone that follows these numbers knows it's true.  What was the point of criticizing it?

I hesitate to pollute this thread with this type of meta-analysis, but it's become less and less fun to read the comments when more and more I see nothing but harsh criticisms of others *opinions.*

Of course, I never said "biases have been fully accounted for". 'Fully' was an adjective you added, and it substantially changes the very meaning of what I wrote. I said--and you even quoted it--"biases have been accounted for". When quoting others, please quote directly and with no addition.

Now, it's no secret that the most frequently-used tool in the denialist's Big Bag 'O Tricks is to choose only those data that agree with their preconceived notions. Had you carefully read what I wrote--and perhaps you'll yet do so, if time permits--you'll see that my issue was not with BBR's statement that one can't always trust the daily numbers; my issue was with his/her statement that one can only trust numbers that show a decrease. Surely you're able to see the difference between the two? The simple fact is, virtually every ice metric shows up and down fluctuations near each's annual maximum and minimum. That's simply the nature of things. And it's intellectually lazy--if not a tad dishonest--to pretend that they don't.

I urge you and everyone else here to please not twist my statements or intentions (or anyone else's, for that matter) into something other than what they are.

Thanks! Now go, and pollute no more... ;)
Title: Re: 2016 sea ice area and extent data
Post by: Xyrus on August 27, 2016, 09:21:59 PM
Seems to me that the 2016 GATF (Great Arctic Toilet Flush) could potentially be getting ready to take place. The 2016 GPAC (Grand Persistent Acrtic Cyclone) has compacted the ice, and now the dipole is going to come in a flush it out the Greenland meltway.
 
This has certainly been an interesting year in the arctic.
Title: Re: 2016 sea ice area and extent data
Post by: Neven on August 27, 2016, 10:01:40 PM
ktonine, the problem is that bbr2314 said that data showing small gains were 'bad', 'corrupted' and 'innacurate'. When these are then offset by large losses, naturally this data is good, holy and accurate. It's a nonsensical way of thinking, and a tad disrespectful to boot to the satellite sensors that work so hard and do what they do consistently, every year. It is very similar to the way deniers think.

Looking at day-to-day fluctuations and pronouncing value judgements like that, is rookie stuff. That's all. Live and learn.

Let's watch the ice and have some patience before jumping to conclusions.
Title: Re: 2016 sea ice area and extent data
Post by: Greenbelt on August 27, 2016, 10:21:43 PM
Wrangel arm shrinking from both sides.

Windmap: https://earth.nullschool.net/#current/wind/surface/level/overlay=mean_sea_level_pressure/orthographic=-84.80,87.61,1024/loc=157.376,81.363 (https://earth.nullschool.net/#current/wind/surface/level/overlay=mean_sea_level_pressure/orthographic=-84.80,87.61,1024/loc=157.376,81.363)
Title: Re: 2016 sea ice area and extent data
Post by: budmantis on August 27, 2016, 10:55:04 PM
Seems to me that the 2016 GATF (Great Arctic Toilet Flush) could potentially be getting ready to take place. The 2016 GPAC (Grand Persistent Acrtic Cyclone) has compacted the ice, and now the dipole is going to come in a flush it out the Greenland meltway.
 
This has certainly been an interesting year in the arctic.

You certainly have a way with acronyms!
Title: Re: 2016 sea ice area and extent data
Post by: TerryM on August 27, 2016, 11:35:41 PM

"You certainly have a way with acronyms"


"Acronyms work initially"
My sweeties boss told this to a room full of cops at a planning session. None even smiled - and he didn't realise what he'd said!


"Police intelligence", an oxymoron


Terry
Title: Re: 2016 sea ice area and extent data
Post by: budmantis on August 28, 2016, 12:32:42 AM
That's a good one Terry!

Bud
Title: Re: 2016 sea ice area and extent data
Post by: Rob Dekker on August 28, 2016, 09:30:34 AM
Big big drops of extent fellows.
These must be accurate! They adhere well to the established theories around.

I am afraid that that 158 k drop is just the beginning of the big extent drops this week...
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on August 28, 2016, 03:05:11 PM
Update for the week to August 27th

The current 5 day trailing average is on 4,800,000km2 while the 1 day extent is at 4,537,000km2.

(All the following data is based on a trailing 5 day average)
The daily anomaly (compared to 81-10) is at -1,930,000km2, an increase from -1,855,000km2 last week. The anomaly compared to the 07, 11 and 12 average is at +247,000km2, an increase from +212,000km2 last week. We're currently 2nd lowest on record, up from 3rd lowest last week.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FYSbmJ6N.png&hash=e06e7104894a4f42274b838674b95f45)

The average daily change over the last 7 days was -55.1k/day, compared to the long term average of -44.4k/day, and the 07, 11 and 12 average of -60.1k/day.
The average long term change over the next week is -38.9k/day, with the 07, 11, and 12 average being -45.2k/day.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FASgHYII.png&hash=645aeaec7d0d279152163b36ca315385)

The extent loss so far this August is the 5th largest on record. To achieve the largest monthly loss, a drop of at least 176.3k/day is required (requiring ~221.0k/day with with single day values), while the smallest loss requires an increase of at least 207.0k/day (+545.3k/day with single day values) and an average loss requires an increase of 73.7k/day (increase of 278.8k/day with single day values).

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2FTTGzqL7.png&hash=b48ed4602f3aa652c3b035f59120ba46)
Title: Re: 2016 sea ice area and extent data
Post by: BornFromTheVoid on August 28, 2016, 03:17:09 PM
Using the single day values, the NSIDC extent is now below every previous minima except 2007, 2011, 2012 and 2015, with gaps of 390k, 204k, 1197k and 196k respectively.

With the 5 day trailing average we're below all previous minima except 2007, 2008, 2010, 2011, 2012 and 2015.

(https://forum.arctic-sea-ice.net/proxy.php?request=http%3A%2F%2Fi.imgur.com%2F54BUIje.png&hash=7ab5262aa84d6103bcfe05c508c4f076)

...Diff..... ...No of Years   Percentage
Below 0..... ....31..... .....83.8%
0-100k....... ....0..... ......0.0%
100-250k..... ...2..... ......5.4%
250-500k..... ...2..... ......5.4%
500-1000k..... .1..... ......2.7%
>1000k..... .....1..... ......2.7%
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 28, 2016, 04:07:11 PM
Here is the shadow CT-area report based on calibrated F18 NSIDC sea ice concentration data:

day  CT-date       NH               SH                Global
Sat 2016.6493 -170.0  2.918565  +56.9 14.809784  -113.1 17.728349
Sun 2016.6521 -109.9  2.808624  -40.2 14.769591  -150.1 17.578215
Mon 2016.6548  -52.5  2.756159  +81.7 14.851282   +29.2 17.607441
Tue 2016.6575  -57.9  2.698250  +53.4 14.904697    -4.5 17.602947


Single handed done by the CAB: -64k.

Shadow NSIDC extent is now 4.5373 dropping -172.4k. Done by the CAB (-132k), Chukchi (-29k) and ESS (-24k).

The left Wrangle arm is in flames in the attached delta image.
Title: Re: 2016 sea ice area and extent data
Post by: Wipneus on August 28, 2016, 04:16:03 PM
NSIDC area (*) is becoming a neck and neck race with only 132k behind 2012.

Date      "NSIDC area"
2015-08-27 3.384752
2010-08-27 3.365565
2008-08-27 3.290108
2011-08-27 3.128499
2007-08-27 3.117733
2016-08-27 2.649995
2012-08-27 2.517081
 
(*) Read my post about when Area is not CT-Area: http://forum.arctic-sea-ice.net/index.php/topic,1457.msg87761.html#msg87761 (http://forum.arctic-sea-ice.net/index.php/topic,1457.msg87761.html#msg87761)
Title: Re: 2016 sea ice area and extent data
Post by: nuwanudaraalwis on August 28, 2016, 04:39:11 PM
Wipneus 2016-08-27 2.649995 vs 2.698250 difference ?
Title: Re: 2016 sea ice area and extent data
Post by: Buddy on August 28, 2016, 08:56:38 PM
Quote
NSIDC area (*) is becoming a neck and neck race with only 132k behind 2012.

Date      "NSIDC area"
2015-08-27 3.384752
2010-08-27 3.365565
2008-08-27 3.290108
2011-08-27 3.128499
2007-08-27 3.117733
2016-08-27 2.649995
2012-08-27 2.517081

Yea....pretty interesting indeed.  And almost 22% below last year....

And there is more "slushy" that is primed and ready to go.
Title: Re: 2016 sea ice area and extent data