Support the Arctic Sea Ice Forum and Blog

Author Topic: 2015 sea ice area and extent data  (Read 700715 times)

seaicesailor

  • Guest
Re: 2015 sea ice area and extent data
« Reply #800 on: August 04, 2015, 06:17:26 PM »
I must add that the NSIDC SIE fell 400K during the past four days.
 

Jim Pettit

  • Nilas ice
  • Posts: 1175
    • View Profile
  • Liked: 41
  • Likes Given: 11
Re: 2015 sea ice area and extent data
« Reply #801 on: August 05, 2015, 01:14:37 PM »
ADS-NIPR Extent:
6,221,434 km2 (04 August)
Down 7,720,626 km2 (55.38%) from 2015 maximum of 13,942,060 km2 on 15 February.
3,043,979 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 59,364 km2 (-.95%) from previous day.
Down 572,436 km2  (-8.43%) over past seven days (daily average: -81,777 km2).
Down 342,428 km2  (-5.22%) for August (daily average: -85,607 km2).
779,671 km2 below 2000s average for this date.
38,487 km2 below 2010s average for this date.
293,025 km2 below 2014 value for this date.
432,934 km2 above 2012 value for this date.
4th lowest August to-date average.
4th lowest value for the date.
64 days this year (29.63% year-to-date) have recorded the lowest daily extent.
32 days (14.81%) have recorded the second lowest.
32 days (14.81%) have recorded the third lowest.
128 days (59.26%) in total have been among the three lowest on record.


CT Area:
NOTE: due to infrequent updates of official CT sea ice area data, I'm using a combination of those official data and Wipneus' calculated area numbers. The official numbers will be inserted as they become available.
4,083,793 km2 (05 August [Day 0.5918])
Down 9,190,762 km2 (69.24%) from 2015 maximum of 13,274,555 km2 on 17 February [Day 0.1288].
1,849,784 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 52,618 km2 (-1.27%) from previous day.
Down 478,896 km2 (-10.5%) over past seven days (daily average: -68,414 km2).
Down 329,236 km2 (-7.46%) for August (daily average: -65,847 km2).
795,017 km2 below 2000s average for this date.
107,425 km2 below 2010s average for this date.
566,886 km2 below 2014 value for this date.
527,561 km2 above 2012 value for this date.
4th lowest August to-date average.
4th lowest value for the date.
7 days this year (3.23% year-to-date) have recorded the lowest daily area.
19 days (8.76%) have recorded the second lowest.
29 days (13.36%) have recorded the third lowest.
55 days in total (25.35%) have been among the lowest three on record.

As of now, 2015 area has fallen below the annual minima recorded in every year prior to and including 2005, with the lone exception of 2002.
« Last Edit: August 05, 2015, 01:46:06 PM by Jim Pettit »

Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4220
    • View Profile
    • Arctische Pinguin
  • Liked: 1025
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #802 on: August 05, 2015, 04:08:06 PM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

Wed       4.134669
Thu -54.3  4.080380
Fri -47.7  4.032717

The next semi-century this Friday has as major supporters the CAB (-34k2) and CAA (-28k4). Kara saw a small increase (+10k).

In the attached NSIDC delta map, pixels with larger concentration changes than 7% or colored pinkish (down) or light blue (up). Solid red and blue are where the pixel concentration crosses the 15% limit (for extent).

Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4220
    • View Profile
    • Arctische Pinguin
  • Liked: 1025
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #803 on: August 06, 2015, 04:46:53 PM »
(A shortened report, I am traveling and on Android)

CT's area value due to be released Saturday is estimated to 4.0099 (-21k2). Almost the same loss as the CAB

plinius

  • Frazil ice
  • Posts: 403
    • View Profile
  • Liked: 0
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #804 on: August 06, 2015, 04:59:13 PM »
and overall extent essentially stalled for today (0.01 increase).

plg

  • New ice
  • Posts: 76
    • View Profile
  • Liked: 1
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #805 on: August 06, 2015, 07:45:46 PM »
(A shortened report, I am traveling and on Android)

CT's area value due to be released Saturday is estimated to 4.0099 (-21k2). Almost the same loss as the CAB

It will then pass 2002 (4.03) and 2006 (4.02), guaranteeing a 9th place (in the ridiculous assumption of no more melt).

Next target is 2013 (3.55).
If you are not paranoid you just do not have enough information yet.

Jim Pettit

  • Nilas ice
  • Posts: 1175
    • View Profile
  • Liked: 41
  • Likes Given: 11
Re: 2015 sea ice area and extent data
« Reply #806 on: August 06, 2015, 10:02:51 PM »
(A shortened report, I am traveling and on Android)

CT's area value due to be released Saturday is estimated to 4.0099 (-21k2). Almost the same loss as the CAB

It will then pass 2002 (4.03) and 2006 (4.02), guaranteeing a 9th place (in the ridiculous assumption of no more melt).

Next target is 2013 (3.55).

True. While nothing is set in stone--or even really hard ice--it's all but certain that 2015 will finish somewhere between 2nd and 4th place

Following is a list of SIA decreases from Day 0.5973 through minimum for each of the past ten years. "IF REPEAT" shows what SIA would be on this year's minimum if it followed the same pattern as each of the ten seasons. The ordinal numbers to the right show what place 2015 would be:

YEAR   LOSS TO END   IF REPEAT   RANK
2014   1.0868075   2.9230925   4th
2013   1.0040970   3.0058030   5th
2012   1.1913576   2.8185424   2nd
2011   0.8770154   3.1328846   6th
2010   1.1166017   2.8932983   2nd
2009   1.0400088   2.9698912   4th
2008   1.1815095   2.8283905   2nd
2007   1.0029833   3.0069167   5th
2006   0.8282280   3.1816720   6th
2005   0.7902527   3.2196473   6th


plg

  • New ice
  • Posts: 76
    • View Profile
  • Liked: 1
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #807 on: August 06, 2015, 10:26:19 PM »
(A shortened report, I am traveling and on Android)

CT's area value due to be released Saturday is estimated to 4.0099 (-21k2). Almost the same loss as the CAB

It will then pass 2002 (4.03) and 2006 (4.02), guaranteeing a 9th place (in the ridiculous assumption of no more melt).

Next target is 2013 (3.55).

True. While nothing is set in stone--or even really hard ice--it's all but certain that 2015 will finish somewhere between 2nd and 4th place

Following is a list of SIA decreases from Day 0.5973 through minimum for each of the past ten years. "IF REPEAT" shows what SIA would be on this year's minimum if it followed the same pattern as each of the ten seasons. The ordinal numbers to the right show what place 2015 would be:

YEAR   LOSS TO END   IF REPEAT   RANK
2014   1.0868075   2.9230925   4th
2013   1.0040970   3.0058030   5th
2012   1.1913576   2.8185424   2nd
2011   0.8770154   3.1328846   6th
2010   1.1166017   2.8932983   2nd
2009   1.0400088   2.9698912   4th
2008   1.1815095   2.8283905   2nd
2007   1.0029833   3.0069167   5th
2006   0.8282280   3.1816720   6th
2005   0.7902527   3.2196473   6th
Interesting statistics.

I have looked at a different metric which far from precise in any way may still give some hints. I calculated the average day of minimum (day  255  = Sep 12) and then calculated the needed daily loss just using an unrealistic straight line. Obviously the melt currently must exceed that daily average (see last two columns):
Code: [Select]
Rank Year Month Day DoY Area Total loss Days to go Daily loss
1 2012 9 13 257 2.2340095 -1.8446062 38 -48542
2 2011 9 11 254 2.9047396 -1.1738761 38 -30892
3 2007 9 8 251 2.9194391 -1.1591766 38 -30505
4 2008 9 8 252 3.0035558 -1.0750599 38 -28291
5 2010 9 9 252 3.0721295 -1.0064862 38 -26487
6 2009 9 10 253 3.4245975 -0.6540182 38 -17211
7 2014 9 11 254 3.4831684 -0.5954473 38 -15670
8 2013 9 11 254 3.5543971 -0.5242186 38 -13795
9 2006 9 24 267 4.0169191 -0.0616966 38 -1624
10 2002 9 7 250 4.0347104 -0.0439053 38 -1155
11 2015 8 5 217 4.0786157 0 38 0
If you are not paranoid you just do not have enough information yet.

Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4220
    • View Profile
    • Arctische Pinguin
  • Liked: 1025
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #808 on: August 07, 2015, 08:21:34 AM »
(post the full information)

From yesterday's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

Thu       4.078616
Fri -47.5  4.031125
Sat -21.2  4.009923

Only the area in the CAB changed significantly (-23k3).

In the attached NSIDC delta map, pixels with larger concentration changes than 7% or colored pinkish (down) or light blue (up). Solid red and blue are where the pixel concentration crosses the 15% limit (for extent).

Vergent

  • Grease ice
  • Posts: 574
    • View Profile
  • Liked: 2
  • Likes Given: 2
Re: 2015 sea ice area and extent data
« Reply #809 on: August 07, 2015, 04:09:12 PM »
NSIDC daily extent:

2015,    08,  05,      6.486,
2015,    08,  06,      8.164,  +1,678k



Oopse

Verg  :o

Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4220
    • View Profile
    • Arctische Pinguin
  • Liked: 1025
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #810 on: August 07, 2015, 04:13:45 PM »
Something went wrong.

plinius

  • Frazil ice
  • Posts: 403
    • View Profile
  • Liked: 0
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #811 on: August 07, 2015, 04:15:50 PM »
;-) couple of seconds faster than me. Is one of the satellites damaged?

BornFromTheVoid

  • Nilas ice
  • Posts: 1339
    • View Profile
  • Liked: 679
  • Likes Given: 299
Re: 2015 sea ice area and extent data
« Reply #812 on: August 07, 2015, 04:16:58 PM »
Or maybe the geoengineering is starting to pay off, albeit with some odd new spatial patterns...

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

Jim Pettit

  • Nilas ice
  • Posts: 1175
    • View Profile
  • Liked: 41
  • Likes Given: 11
Re: 2015 sea ice area and extent data
« Reply #813 on: August 07, 2015, 04:22:21 PM »
Or maybe the geoengineering is starting to pay off, albeit with some odd new spatial patterns...



Well, then. Just eyeballing, it looks like extent dropped by about 1.5 million km2 yesterday. That's got to be some kind of a daily record, right? :)

DavidR

  • Grease ice
  • Posts: 740
    • View Profile
  • Liked: 36
  • Likes Given: 3
Re: 2015 sea ice area and extent data
« Reply #814 on: August 07, 2015, 04:39:03 PM »
Or maybe the geoengineering is starting to pay off, albeit with some odd new spatial patterns...



Well, then. Just eyeballing, it looks like extent dropped by about 1.5 million km2 yesterday. That's got to be some kind of a daily record, right? :)
But according to NSIDC it went  up  by 1.7 million. I think I'll wake up the morning and this will all just  be a bad dream.
Toto, I've a feeling we're not in Kansas anymore

BornFromTheVoid

  • Nilas ice
  • Posts: 1339
    • View Profile
  • Liked: 679
  • Likes Given: 299
Re: 2015 sea ice area and extent data
« Reply #815 on: August 07, 2015, 04:45:00 PM »
It's definitely a daily record. However, the real question is - how did weatherdude88 know this was coming!?
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

Vergent

  • Grease ice
  • Posts: 574
    • View Profile
  • Liked: 2
  • Likes Given: 2
Re: 2015 sea ice area and extent data
« Reply #816 on: August 07, 2015, 06:14:00 PM »


It looks similar to a failure they had in Feb, 2009. If so recent data may also be corrupted due to sensor drift.

http://nsidc.org/arcticseaicenews/2009/02/satellite-sensor-errors-cause-data-outage/

Verg


Rick Aster

  • New ice
  • Posts: 71
    • View Profile
  • Liked: 1
  • Likes Given: 1
Re: 2015 sea ice area and extent data
« Reply #817 on: August 07, 2015, 08:40:44 PM »
Sorry, I should have posted this here first. NSIDC confirms a flaw in the data, "a problem . . .with the F17 DMSP satellite" and not much more detail than that: http://nsidc.org/arcticseaicenews/

Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4220
    • View Profile
    • Arctische Pinguin
  • Liked: 1025
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #818 on: August 08, 2015, 08:33:42 AM »
Quote
Notice: On 5 August 2015, a problem arose with the F17 DMSP satellite that provides data to generate these images which led to missing data. The satellite appears to be back to normal operation, but NSIDC is monitoring the F17 data stream. We have removed the bad data resulting in data gaps.

(color: NSIDC)



NSIDC did update sea ice concentration for 5th and 6th August. In both large slices are marked "unavailable". Not enough valid remains for a reliable reconstruction, as can be seen on attached image a sliver remains that my program does not fill in. This will affect some of my graphs with NSIDC based data in it.
Hopefully when the satellite gives no further problems, I can resume posting expected CT-area updates tomorrow.

Jim Pettit

  • Nilas ice
  • Posts: 1175
    • View Profile
  • Liked: 41
  • Likes Given: 11
Re: 2015 sea ice area and extent data
« Reply #819 on: August 08, 2015, 02:04:25 PM »
NSIDC did update sea ice concentration for 5th and 6th August. In both large slices are marked "unavailable". Not enough valid remains for a reliable reconstruction, as can be seen on attached image a sliver remains that my program does not fill in. This will affect some of my graphs with NSIDC based data in it.
Hopefully when the satellite gives no further problems, I can resume posting expected CT-area updates tomorrow.

Keeping my fingers crossed. In the meantime, Cryosphere Today has updated their  "official" area numbers through Day 0.5973, and they show that SIA has fallen below the 4M km2 threshold 12 days ahead of 2013 and 19 full days ahead of 2014. Only 2007 (two days quicker), 2011 (five days), and 2012 (six days) fell below 4 million as fast.  Meaning: while first place is all but an impossibility at this point, 2015 has a great shot at ending up anywhere from second to fifth place.

Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4220
    • View Profile
    • Arctische Pinguin
  • Liked: 1025
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #820 on: August 08, 2015, 02:46:18 PM »
NSIDC did update sea ice concentration for 5th and 6th August. In both large slices are marked "unavailable". Not enough valid remains for a reliable reconstruction, as can be seen on attached image a sliver remains that my program does not fill in. This will affect some of my graphs with NSIDC based data in it.
Hopefully when the satellite gives no further problems, I can resume posting expected CT-area updates tomorrow.

Keeping my fingers crossed. In the meantime, Cryosphere Today has updated their  "official" area numbers through Day 0.5973, and they show that SIA has fallen below the 4M km2 threshold 12 days ahead of 2013 and 19 full days ahead of 2014. Only 2007 (two days quicker), 2011 (five days), and 2012 (six days) fell below 4 million as fast.  Meaning: while first place is all but an impossibility at this point, 2015 has a great shot at ending up anywhere from second to fifth place.

That is a drop of -81k. The original 20150805 NSIDC implies a drop of -21k, so they have clearly used the revised data.
However this data contains a large gap of unavailable data that must be filled in somehow (avoiding drops of thousand of k's).
Using interpolated data from 20150804 and 20150806, I calculate a drop of -42k7(3.990632).

CT clearly does something different.

Buddy

  • Young ice
  • Posts: 3379
  • Go DUCKS!!
    • View Profile
  • Liked: 49
  • Likes Given: 34
Re: 2015 sea ice area and extent data
« Reply #821 on: August 08, 2015, 03:06:20 PM »
Quote
Only 2007 (two days quicker), 2011 (five days), and 2012 (six days) fell below 4 million as fast.  Meaning: while first place is all but an impossibility at this point, 2015 has a great shot at ending up anywhere from second to fifth place.

And if you look at volume (via DMI)....looks as though 2015 may end up in 2nd place for the lowest volume.  Right now....it is only behind 2012 volume melt, and slightly ahead of 2011 volume melt.  The 2015 volume melt is WAY ahead of the 2013 and 2014.


http://ocean.dmi.dk/arctic/icethickness/images/FullSize_CICE_combine_thick_SM_EN_20150807.png
FOX (RT) News....."The Trump Channel.....where truth and journalism are dead."

plg

  • New ice
  • Posts: 76
    • View Profile
  • Liked: 1
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #822 on: August 08, 2015, 04:21:07 PM »
Fresh data from NSIDC now downloadable. Has reasonable numbers, the glitch seems to have been corrected.
If you are not paranoid you just do not have enough information yet.

seaicesailor

  • Guest
Re: 2015 sea ice area and extent data
« Reply #823 on: August 08, 2015, 06:09:27 PM »
Fresh data from NSIDC now downloadable. Has reasonable numbers, the glitch seems to have been corrected.

If data ok, that is 425K of loss for the past 5 days. Not bad for a slowdown.


Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4220
    • View Profile
    • Arctische Pinguin
  • Liked: 1025
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #824 on: August 09, 2015, 04:20:51 PM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

Sat       3.952008
Sun -90.1  3.861935
Mon -65.9  3.796026
Tue -7.1  3.788940


NOTE: assuming that the difficulties with the DMSP-F17 satellite are over, the final value (3.796) for Monday should be correct within the usual margin of 2-3k. I expect the delta's for Sunday and Monday to be off by much larger margins (perhaps more than 100k). 
If NSIDC makes any changes to these data, then these efforst are wasted.

The nearly zero change for Tuesday is the result of a decline in the Greenland Sea (-22k9) and of "lake ice" (-11k). There are increases for the CAB (+23k8) and the CAA (+16k9).

NSIDC extent sees some large swings: Greenland Sea (-52k), CAA (+57k7), East Siberian Sea "coastal" ice (-25k3). Not nice, knowing the instrumental problems.

In the attached NSIDC delta map, pixels with larger concentration changes than 7% or colored pinkish (down) or light blue (up). Solid red and blue are where the pixel concentration crosses the 15% limit (for extent).

BornFromTheVoid

  • Nilas ice
  • Posts: 1339
    • View Profile
  • Liked: 679
  • Likes Given: 299
Re: 2015 sea ice area and extent data
« Reply #825 on: August 09, 2015, 04:42:43 PM »
Update for the week to August 8th

The current 5 day mean is on 6,383,400km2 while the 1 day extent is at 6,238,000km2.
The daily anomaly (compared to 81-10) is at -1,359,140km2, an increase from -1,321,970km2 last week. The anomaly compared to the 07, 11 and 12 average is at +453,267km2, an increase from +365,200km2 last week. We're currently 4th lowest on record, up from 5th last week.



The average daily change over the last 7 days was -79.9k/day, compared to the long term average of -74.7k/day, and the 07, 11 and 12 average of -96.2k/day.
The average long term change over the next week is -62.7k/day, with the 07, 11, and 12 average being -87.7k/day.



The loss so far this August is the 12th largest on record. To achieve the largest monthly drop, a daily loss of at least 91.8k/day is required, while the smallest drop requires a loss of no more than 25.2k/day and an average drop requires a loss of 48.3k/day.

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

OldLeatherneck

  • Grease ice
  • Posts: 554
    • View Profile
  • Liked: 2
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #826 on: August 09, 2015, 07:13:35 PM »
Updated ADR-NIPR SIE Projections

During the first 8 days of August, SIE lost  567,464 KM2. The average daily loss was 70,933 KM2 which  is only marginally more than the 2003-2014 average of 70,118 KM2.

 Due to the current state of the ice in the Bering Sea, I would anticipate continued fluctuations in daily SIE losses,  However, I still project that losses will continue to be average, if not somewhat above average through the 15th.  I'm becoming move convinced that 2015 will end the season in at least 4th place, with  a reasonable chance of going lower than 2011.  With significant losses in September, such as in 2010 when the SIE dropped ~500K KM2 and didn't reach the bottom until the 21st, there is some possibility of ended up 2nd, lower than 2007.


"Share Your Knowledge.  It's a Way to Achieve Immortality."  ......the Dalai Lama

seaicesailor

  • Guest
Re: 2015 sea ice area and extent data
« Reply #827 on: August 09, 2015, 07:44:14 PM »
Updated ADR-NIPR SIE Projections

During the first 8 days of August, SIE lost  567,464 KM2. The average daily loss was 70,933 KM2 which  is only marginally more than the 2003-2014 average of 70,118 KM2.

 Due to the current state of the ice in the Bering Sea, I would anticipate continued fluctuations in daily SIE losses,  However, I still project that losses will continue to be average, if not somewhat above average through the 15th.  I'm becoming move convinced that 2015 will end the season in at least 4th place, with  a reasonable chance of going lower than 2011.  With significant losses in September, such as in 2010 when the SIE dropped ~500K KM2 and didn't reach the bottom until the 21st, there is some possibility of ended up 2nd, lower than 2007.


2015 has more potential for melting and compaction than 2011 had IMHO, see 2011 bremen map below. Chances are indeed high.



Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4220
    • View Profile
    • Arctische Pinguin
  • Liked: 1025
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #828 on: August 10, 2015, 04:14:24 PM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

Sun       3.833869
Mon -65.9  3.767961
Tue -7.0  3.761006
Wed -28.6  3.732454

NOTE: today's (Monday) CT update is likely to be off +60 - +80k. IF NSIDC does not revise the data, the numbers for the following days should be accurate again.

Wednesday does not change much, biggest contributor is Beaufort: -14k3.

In the attached NSIDC delta map, pixels with larger concentration changes than 7% or colored pinkish (down) or light blue (up). Solid red and blue are where the pixel concentration crosses the 15% limit (for extent).

Jim Pettit

  • Nilas ice
  • Posts: 1175
    • View Profile
  • Liked: 41
  • Likes Given: 11
Re: 2015 sea ice area and extent data
« Reply #829 on: August 10, 2015, 04:39:18 PM »
ADS-NIPR Extent:
5,903,228 km2 (09 August)
Down 8,038,832 km2 (57.66%) from 2015 maximum of 13,942,060 km2 on 15 February.
2,725,773 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 93,170 km2 (-1.55%) from previous day.
Down 494,778 km2  (-7.73%) over past seven days (daily average: -70,683 km2).
Down 660,634 km2  (-10.06%) for August (daily average: -73,404 km2).
768,201 km2 below 2000s average for this date.
23,829 km2 above 2010s average for this date.
355,901 km2 below 2014 value for this date.
867,435 km2 above 2012 value for this date.
4th lowest August to-date average.
4th lowest value for the date.
64 days this year (28.96% year-to-date) have recorded the lowest daily extent.
32 days (14.48%) have recorded the second lowest.
32 days (14.48%) have recorded the third lowest.
128 days (57.92%) in total have been among the three lowest on record.


CT Area:
NOTE: due to infrequent updates of official CT sea ice area data, I'm using a combination of those official data and Wipneus' calculated area numbers. The official numbers will be inserted as they become available.
3,732,454 km2 (11 August [Day 0.6083])
Down 9,542,101 km2 (71.88%) from 2015 maximum of 13,274,555 km2 on 17 February [Day 0.1288].
1,498,445 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 28,552 km2 (-.76%) from previous day.
Down 402,215 km2 (-9.73%) over past seven days (daily average: -57,459 km2).
Down 680,575 km2 (-15.42%) for August (daily average: -61,870 km2).
897,189 km2 below 2000s average for this date.
156,197 km2 below 2010s average for this date.
824,725 km2 below 2014 value for this date.
632,872 km2 above 2012 value for this date.
4th lowest August to-date average.
4th lowest value for the date.
7 days this year (3.14% year-to-date) have recorded the lowest daily area.
19 days (8.52%) have recorded the second lowest.
31 days (13.9%) have recorded the third lowest.
57 days in total (25.56%) have been among the lowest three on record.


OldLeatherneck

  • Grease ice
  • Posts: 554
    • View Profile
  • Liked: 2
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #830 on: August 10, 2015, 04:44:57 PM »
The Current ADR-NIPR SIE is 5,903,228 KM2 with a 1-day drop of 93,170 KM2.  2015 now lags behind the 3 record low years by:

2011 -   95,473 KM2
2007 - 465,112 KM2
2012 - 867,435 KM2   

It will be interesting to watch the next few to see what the effect of predicted cyclones have on all of the rubble in the Bering Sea.  Also, I've been following the chatter on the 2015 Melting Season topic about whether 2015 will have a extended melting season due to above average SSTs and surface temperatures in the Northern Hemisphere.

In any case, it's time to stock up on beer and snacks because getting exciting!!
      
   
"Share Your Knowledge.  It's a Way to Achieve Immortality."  ......the Dalai Lama

Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4220
    • View Profile
    • Arctische Pinguin
  • Liked: 1025
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #831 on: August 11, 2015, 12:17:46 PM »
I was right about Monday being off: instead of a -65k drop CT came out with a small increase.

I was not so correct when I said Tuesday and Wednesday should be correct. The daily change values are still OK, but the absolute figures are based on CT's last value. Since that was wrong (IMHO), the absolute values are wrong.

Better not to calculate these values from the last known value from CT, but report my direct calculation. That will give slightly larger deviations in the melt season (~3k max), but it will not fail as bad as it does now.

This is the revised list:


day   chg  estimate  CT-value
Mon        3.835593  3.836345
Tue  -7.0  3.828638  -
Wed -28.6  3.800086  -


Hope it is clear this way, let me know if you are confused.

Sorry Jim, your rankings may be off.

Jim Pettit

  • Nilas ice
  • Posts: 1175
    • View Profile
  • Liked: 41
  • Likes Given: 11
Re: 2015 sea ice area and extent data
« Reply #832 on: August 11, 2015, 01:18:07 PM »
I was right about Monday being off: instead of a -65k drop CT came out with a small increase.

I was not so correct when I said Tuesday and Wednesday should be correct. The daily change values are still OK, but the absolute figures are based on CT's last value. Since that was wrong (IMHO), the absolute values are wrong.

Better not to calculate these values from the last known value from CT, but report my direct calculation. That will give slightly larger deviations in the melt season (~3k max), but it will not fail as bad as it does now.

This is the revised list:


day   chg  estimate  CT-value
Mon        3.835593  3.836345
Tue  -7.0  3.828638  -
Wed -28.6  3.800086  -


Hope it is clear this way, let me know if you are confused.

Sorry Jim, your rankings may be off.

Thanks. But, nah, my rankings are fine; CT SIA has been in 4th place (behind 2012, 2011, and 2007) every day this month, so that hasn't changed despite the recent oddities. For the record, only 2008 is close on 2015's tail; others years are several hundred thousand km2 behind. (Even 2014 is a bit over three-quarters of a million square kilometers back.)

I still believe 2015's best chances are to end up just under or just over 3M km2. IOW, between 2nd and 5th places...

BONUS STAT: This month's to-date SIA average is already lower than the averages for the entire month of August in 2014, 2013, 2009, and every year before 2007.

(Thanks as always for all you do.)

Buddy

  • Young ice
  • Posts: 3379
  • Go DUCKS!!
    • View Profile
  • Liked: 49
  • Likes Given: 34
Re: 2015 sea ice area and extent data
« Reply #833 on: August 11, 2015, 01:23:17 PM »
Quote
BONUS STAT: This month's to-date SIA average is already lower than the averages for the entire month of August in 2014, 2013, 2009, and every year before 2007
.

Certainly shows that 2013 and 2014 were certainly anomalies (as if we didn't know that already).  But that bonus stat certainly does a nice job of "framing" just how bad the ice is.....and how quickly and THOROUGHLY those two "bounce years" have been wiped out....and wiped out quickly.

 
FOX (RT) News....."The Trump Channel.....where truth and journalism are dead."

seaicesailor

  • Guest
Re: 2015 sea ice area and extent data
« Reply #834 on: August 11, 2015, 07:18:29 PM »
Did the NSIDC SIE lose 210K today or is this part of the recent problems??

BTW, below 5 M.
Sorry, below 6 M, 5,997k Km2 to be more precise  :-[

Shared Humanity

  • Guest
Re: 2015 sea ice area and extent data
« Reply #835 on: August 12, 2015, 03:23:03 AM »
I believe it is called a "dead cat bounce".  ::)

Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4220
    • View Profile
    • Arctische Pinguin
  • Liked: 1025
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #836 on: August 12, 2015, 11:52:53 AM »
From the latest (Tuesday) NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

day   chg  estimate  CT-value
Tue        3.828638  3.828482
Wed -28.6  3.800081  -
Thu -129.1  3.671013  -

Major supporter of that century is the CAB (-67k5). Also support from CAA (-25k4) and Beaufort (-20k5).

In the attached NSIDC delta map, pixels with larger concentration changes than 7% or colored pinkish (down) or light blue (up). Solid red and blue are where the pixel concentration crosses the 15% limit (for extent).

AmbiValent

  • Frazil ice
  • Posts: 136
    • View Profile
  • Liked: 7
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #837 on: August 12, 2015, 12:19:37 PM »
Wipneus, has the error in NSIDC data been fully corrected by now?
Bright ice, how can you crack and fail? How can the ice that seemed so mighty suddenly seem so frail?

Jim Pettit

  • Nilas ice
  • Posts: 1175
    • View Profile
  • Liked: 41
  • Likes Given: 11
Re: 2015 sea ice area and extent data
« Reply #838 on: August 12, 2015, 12:43:05 PM »
ADS-NIPR Extent:
5,722,632 km2 (11 August)
Down 8,219,428 km2 (58.95%) from 2015 maximum of 13,942,060 km2 on 15 February.
2,545,177 km2 above record minimum extent of 3,177,455 km2 (16 September 2012).
Down 81,582 km2 (-1.41%) from previous day.
Down 498,802 km2  (-8.02%) over past seven days (daily average: -71,257 km2).
Down 841,230 km2  (-12.82%) for August (daily average: -76,475 km2).
840,406 km2 below 2000s average for this date.
11,750 km2 below 2010s average for this date.
384,768 km2 below 2014 value for this date.
834,654 km2 above 2012 value for this date.
4th lowest August to-date average.
4th lowest value for the date.
64 days this year (28.7% year-to-date) have recorded the lowest daily extent.
32 days (14.35%) have recorded the second lowest.
32 days (14.35%) have recorded the third lowest.
128 days (57.4%) in total have been among the three lowest on record.


CT Area:
NOTE: due to infrequent updates of official CT sea ice area data, I'm using a combination of those official data and Wipneus' calculated area numbers. The official numbers will be inserted as they become available.
3,671,013 km2 (12 August [Day 0.611])
Down 9,603,542 km2 (72.35%) from 2015 maximum of 13,274,555 km2 on 17 February [Day 0.1288].
1,437,004 km2 above record minimum area of 2,234,010 km2 (14 September 2012).
Down 128,498 km2 (-3.38%) from previous day.
Down 407,603 km2 (-9.99%) over past seven days (daily average: -58,229 km2).
Down 742,016 km2 (-16.81%) for August (daily average: -61,835 km2).
926,516 km2 below 2000s average for this date.
211,645 km2 below 2010s average for this date.
906,964 km2 below 2014 value for this date.
558,164 km2 above 2012 value for this date.
4th lowest August to-date average.
4th lowest value for the date.
7 days this year (3.13% year-to-date) have recorded the lowest daily area.
19 days (8.48%) have recorded the second lowest.
29 days (12.95%) have recorded the third lowest.
55 days in total (24.55%) have been among the lowest three on record.

Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4220
    • View Profile
    • Arctische Pinguin
  • Liked: 1025
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #839 on: August 12, 2015, 04:00:07 PM »
Wipneus, has the error in NSIDC data been fully corrected by now?

The latest NSIDC updates do not have large amounts of data marked as "unavailable" as in 5/6th August. That is what was causing the difference between CT's and my calculation.

It depends on NSIDC whether the data is now "fully corrected".

AmbiValent

  • Frazil ice
  • Posts: 136
    • View Profile
  • Liked: 7
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #840 on: August 12, 2015, 04:11:33 PM »
I am a bit confused since the NSIDC graph kept going back to normal but you still said the values were off for some days afterwards.
Bright ice, how can you crack and fail? How can the ice that seemed so mighty suddenly seem so frail?

Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4220
    • View Profile
    • Arctische Pinguin
  • Liked: 1025
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #841 on: August 12, 2015, 04:41:55 PM »
I am a bit confused since the NSIDC graph kept going back to normal but you still said the values were off for some days afterwards.

I find that when NSIDC corrects some faulty values,  CT rarely uses the new corrected values. In fact I doubt if any of the CT values is ever corrected once it was properly merged in the data file. All data is corrected by NSIDC at least once.

Neven

  • Administrator
  • First-year ice
  • Posts: 9470
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 1333
  • Likes Given: 617
Re: 2015 sea ice area and extent data
« Reply #842 on: August 12, 2015, 05:19:31 PM »
Wipneus, one silly question from me, if you'll allow it: your pre-calculated data was always one day in advance of JAXA SIE (we had talked about that, had to do with CT), but now they're the same day. I checked, but haven't missed a day, it seems.

Anyway, it's not that important, but maybe it doesn't take you long to see if there's an issue.
The enemy is within
Don't confuse me with him

E. Smith

Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4220
    • View Profile
    • Arctische Pinguin
  • Liked: 1025
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #843 on: August 12, 2015, 05:20:13 PM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

day   chg  estimate  CT-value
Wed        3.800081  3.799511
Thu -128.9  3.671149  -
Fri -84.3  3.586815  -

The support for Friday's decline are the CAB (-48k7), CAA (-33k5) and also the ESS (-11k5).

The CAA makes some mighty swings at the moment (NSIDC extent dropped -92k). Some of this is caused by the large field of view of the SSMI/S instrument used compared to the narrowness of the channels between the islands.

In the attached NSIDC delta map, pixels with larger concentration changes than 7% or colored pinkish (down) or light blue (up). Solid red and blue are where the pixel concentration crosses the 15% limit (for extent).

Neven

  • Administrator
  • First-year ice
  • Posts: 9470
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 1333
  • Likes Given: 617
Re: 2015 sea ice area and extent data
« Reply #844 on: August 12, 2015, 05:25:36 PM »
Everything SNAFU again. Thanks for the ultra-quick reply, Wip.  ;)

CT SIA dips below 2007.
The enemy is within
Don't confuse me with him

E. Smith

Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4220
    • View Profile
    • Arctische Pinguin
  • Liked: 1025
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #845 on: August 12, 2015, 05:36:15 PM »
Wipneus, one silly question from me, if you'll allow it: your pre-calculated data was always one day in advance of JAXA SIE (we had talked about that, had to do with CT), but now they're the same day. I checked, but haven't missed a day, it seems.

Anyway, it's not that important, but maybe it doesn't take you long to see if there's an issue.

Neven, my today's pre-calculated CT data, in the table above marked Friday, is in reality based on NSIDC measurements from yesterday 11th of August.

ADS-NIPR-Jaxa data released today is also marked 11th of August.
However because of filtering we understand (and the data does show it) this value is based on measurements on the 10th and the 11th of August. Effectively this delays the data by half a day, small but measurable.

Now there is also Jaxa gridded sea ice concentration (that I use in my graphs) that has yet another timing. Shall I explain that another time?

Neven

  • Administrator
  • First-year ice
  • Posts: 9470
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 1333
  • Likes Given: 617
Re: 2015 sea ice area and extent data
« Reply #846 on: August 12, 2015, 05:43:15 PM »
No need to explain, Wipneus, thanks. I know that in this case your CT SIA pre-calculation is one day ahead of JAXA SIE because of that annoying way of CT dating (well, to me its annoying, but I can live with it).

I just like things to stay the way they are. I'm a bit conservative that way and like my routines.  :)
The enemy is within
Don't confuse me with him

E. Smith

Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4220
    • View Profile
    • Arctische Pinguin
  • Liked: 1025
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #847 on: August 13, 2015, 04:17:24 PM »
From today's NSIDC data update I calculate the following CT updates (the days in this list are the days of data released, three days behind ice dates):

day   chg  estimate  CT-value
Thu        3.671149  3.670249
Fri -84.0  3.587187  -
Sat  -5.6  3.581572  -

The small decline is because only the ESS shows a significant change: -14k1

In the attached NSIDC delta map, pixels with larger concentration changes than 7% or colored pinkish (down) or light blue (up). Solid red and blue are where the pixel concentration crosses the 15% limit (for extent).

plg

  • New ice
  • Posts: 76
    • View Profile
  • Liked: 1
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #848 on: August 14, 2015, 03:29:20 PM »
...
I have looked at a different metric which far from precise in any way may still give some hints. I calculated the average day of minimum (day  255  = Sep 12) and then calculated the needed daily loss just using an unrealistic straight line. Obviously the melt currently must exceed that daily average (see last two columns):
Code: [Select]
Rank Year Month Day DoY Area Total loss Days to go Daily loss
1 2012 9 13 257 2.2340095 -1.8446062 38 -48542
2 2011 9 11 254 2.9047396 -1.1738761 38 -30892
3 2007 9 8 251 2.9194391 -1.1591766 38 -30505
4 2008 9 8 252 3.0035558 -1.0750599 38 -28291
5 2010 9 9 252 3.0721295 -1.0064862 38 -26487
6 2009 9 10 253 3.4245975 -0.6540182 38 -17211
7 2014 9 11 254 3.4831684 -0.5954473 38 -15670
8 2013 9 11 254 3.5543971 -0.5242186 38 -13795
9 2006 9 24 267 4.0169191 -0.0616966 38 -1624
10 2002 9 7 250 4.0347104 -0.0439053 38 -1155
11 2015 8 5 217 4.0786157 0 38 0

Update on the table shown above:
Code: [Select]
Rank Year Month Day DoY Area Needed loss Days to go Daily loss
1 2012 9 13 257 2.2340095 -1.3527329 30 -45091.1
2 2011 9 11 254 2.9047396 -0.6820028 30 -22733.4
3 2007 9 8 251 2.9194391 -0.6673033 30 -22243.4
4 2008 9 8 252 3.0035558 -0.5831866 30 -19439.6
5 2010 9 9 252 3.0721295 -0.5146129 30 -17153.8
6 2009 9 10 253 3.4245975 -0.1621449 30 -5404.8
7 2014 9 11 254 3.4831684 -0.1035740 30 -3452.5
8 2013 9 11 254 3.5543971 -0.0323453 30 -1078.2
9 2015 8 13 225 3.5867424 0 30 0

Some notes: there is a cluster at around 3.4-3.5 (2009, 2014 and 2013), which will presumably soon be passed (need only 162k which is perhaps a week or less?). The next cluster is at 2.9-3.1 (2011, 2007, 2008, 2010) which needs about 680k to pass. There are still 30 days of melt till the average day of minimum, and if the minimum will be late then perhaps up to 40 days. The last "cluster" is of course the 2012 outlier at 2.23.
If you are not paranoid you just do not have enough information yet.

plg

  • New ice
  • Posts: 76
    • View Profile
  • Liked: 1
  • Likes Given: 0
Re: 2015 sea ice area and extent data
« Reply #849 on: August 14, 2015, 03:43:39 PM »
A different metric is to look at is the total area loss:
Code: [Select]
Rank Year Max Min Area loss
1 2012 13.7085104 2.2340095 83.7%
2 2008 13.8907156 3.0035558 78.4%
3 2007 13.3171978 2.9194391 78.1%
4 2011 13.1444197 2.9047396 77.9%
5 2010 13.8120375 3.0721295 77.8%
6 2009 13.8530560 3.4245975 75.3%
7 2013 13.7991982 3.5543971 74.2%
8 2014 13.4873371 3.4831684 74.2%
9 2015 13.2745552 3.5867424 73.0% <======
10 2002 14.3224802 4.0347104 71.8%
11 2003 14.3390617 4.1416645 71.1%
12 1998 14.5411863 4.2624030 70.7%
13 1999 14.2953978 4.2044988 70.6%
14 2000 13.9185286 4.1687655 70.0%
15 2006 13.3582220 4.0169191 69.9%
16 1993 14.7550344 4.4729533 69.7%
17 2005 13.4600563 4.0917983 69.6%
18 1995 14.2743616 4.4103012 69.1%
19 2004 13.7756853 4.2829733 68.9%
20 2001 14.5263119 4.5336194 68.8%
21 1991 14.2229528 4.4603844 68.6%
22 1990 14.6883049 4.6289349 68.5%
23 1984 14.2622805 4.6958923 67.1%
24 1994 14.5278549 4.8160958 66.8%
25 1989 14.1837082 4.8159156 66.0%
26 1997 14.3325729 4.8997059 65.8%
27 1985 14.5948057 4.9928470 65.8%
28 1988 15.0071096 5.1448908 65.7%
29 1981 14.3082495 4.9564924 65.4%
30 1982 14.7734251 5.1390600 65.2%
31 1992 14.3987179 5.0267782 65.1%
32 1979 15.0746040 5.3067255 64.8%
33 1987 14.6827326 5.2889948 64.0%
34 1983 14.7548742 5.3869290 63.5%
35 1986 14.4870262 5.3818426 62.9%
36 1980 14.7429981 5.5077119 62.6%
37 1996 13.8432703 5.2381849 62.2%

Also here there are three clusters:  at ~74-75% (2009, 2013, 2014), the next is around 78% (2008, 2007, 2011, 2010), and  2012 on its own at 83.7%.

I was surprised that 2015 already is at 73% loss, given that the maximum was so low.

Assuming that 2015 also reaches a loss matching the second cluster at 78%, the final area would be around 2,87-2.95, thus placing the minimum at 2nd-4th place.

The predictive power of this exercise in numerology is very low, except confirming how unlikely it is to surpass 2012, as has been pointed out repeatedly elsewhere.
If you are not paranoid you just do not have enough information yet.