Please support this Forum and Neven's Blog

Author Topic: IJIS  (Read 1489777 times)

Bill Fothergill

  • ASIF Citizen
  • Posts: 272
    • View Profile
Re: IJIS
« Reply #4150 on: April 15, 2017, 08:58:36 AM »
We read the Arctic Sea Ice Forum here on Pluto too, you know. Earth bigot!

P.S. Pluto is so a planet.

Clyde Tombaugh sends his regards. (Or would, were he still amongst us.)

DavidR

  • ASIF Middle Class
  • Posts: 565
    • View Profile
Re: IJIS
« Reply #4151 on: April 15, 2017, 09:35:41 AM »
@Bill,

That chart of "lowest three" ice extents - does it measure the lowest three so far up to the year in question or does it consider future years too? ie if 2012 set a record for a given day which 2016 subsequently beat, would the day be ranked as a "lowest" or a "second lowest" for 2012?
The chart of lowest three extents is based on the  latest date. So for the next  5 days, 2007  which is third will become fourth and lose 5 days at third from its total.

Bill Fothergill

  • ASIF Citizen
  • Posts: 272
    • View Profile
Re: IJIS
« Reply #4152 on: April 15, 2017, 11:11:56 AM »
@Bill,

That chart of "lowest three" ice extents - does it measure the lowest three so far up to the year in question or does it consider future years too? ie if 2012 set a record for a given day which 2016 subsequently beat, would the day be ranked as a "lowest" or a "second lowest" for 2012?

Paddy,
As David correctly stated above, the stacked bar chart updates as each new data point for 2017 comes in. However, that's only the case for the chart on my computer; the one shown in yesterday's comment is merely a static GIF representation.

Since the data for Day 104 (April 14th) has been added, the number of "lowest" places for 2017 has risen from 55 to 56. However, this introduces a "shuffle effect", with 2016 losing a "lowest" but gaining a "2nd", 2004 losing a "2nd" but gaining a "3rd", and 2007 losing a "3rd".

My intention is to re-post an updated version of the stacked bar chart each time something significant happens. I suspect the next such instance will be when 2017 overtakes 2007 in terms of  total number of appearances in the lowest 3.

Espen

  • ASIF Governor
  • Posts: 3013
    • View Profile
Re: IJIS
« Reply #4153 on: April 15, 2017, 12:05:13 PM »
IJIS:

13,120,623 km2(April 14, 2017)down 34,702 km2 and lowest measured for the date.
Have a ice day!

Espen

  • ASIF Governor
  • Posts: 3013
    • View Profile
Re: IJIS
« Reply #4154 on: April 16, 2017, 08:37:28 AM »
IJIS:

13,119,114 km2(April 15, 2017)down 1,509 km2 and lowest measured for the date.
Have a ice day!

Espen

  • ASIF Governor
  • Posts: 3013
    • View Profile
Re: IJIS
« Reply #4155 on: April 17, 2017, 09:15:20 AM »
IJIS:

13,094,044 km2(April 16, 2017)down 25,070 km2 and lowest measured for the date.
Have a ice day!

Oyvind Johnsen

  • ASIF Lurker
  • Posts: 16
    • View Profile
Re: IJIS
« Reply #4156 on: April 17, 2017, 12:57:55 PM »
IJIS is really heading south now April 17, 2013:

13,174,375 km2

Now at 2000s average, but with this attitude go below that within days, easily.

This thread started with the Message above. But I can´t find a green line for 2013 at this point in the graph. And 2000s average? Can anyone explain this?

crandles

  • ASIF Upper Class
  • Posts: 1719
    • View Profile
Re: IJIS
« Reply #4157 on: April 17, 2017, 01:22:23 PM »
IJIS is really heading south now April 17, 2013:

13,174,375 km2

Now at 2000s average, but with this attitude go below that within days, easily.

This thread started with the Message above. But I can´t find a green line for 2013 at this point in the graph. And 2000s average? Can anyone explain this?

Sorry can't see the problem

oren

  • ASIF Upper Class
  • Posts: 1473
    • View Profile
Re: IJIS
« Reply #4158 on: April 17, 2017, 03:36:39 PM »
The problem if I understand correctly is that the 2013 line and the 2000s average are not at 13.174 but much higher  :o
Must have been some kind of revision from then to now?
« Last Edit: April 17, 2017, 03:42:18 PM by oren »

deinst

  • ASIF Lurker
  • Posts: 3
    • View Profile
Re: IJIS
« Reply #4159 on: April 17, 2017, 05:34:42 PM »
The problem if I understand correctly is that the 2013 line and the 2000s average are not at 13.174 but much higher  :o
Must have been some kind of revision from then to now?

Yes.  On 06 September 2013 there was a change in the data set -- see comment #406.  Unfortunately the descriptive link is broken.  I believe that the change had to do with the handling of the land masks, but Epsen or Wipneus would know much more than I do.

Everything after Sep 2013 seems comparable, stuff before has a different calibrationr

Espen

  • ASIF Governor
  • Posts: 3013
    • View Profile
Re: IJIS
« Reply #4160 on: April 18, 2017, 05:23:16 AM »
IJIS:

13,069,913 km2(April 17, 2017)down 24,131 km2 and lowest measured for the date.
Have a ice day!

Oyvind Johnsen

  • ASIF Lurker
  • Posts: 16
    • View Profile
Re: IJIS
« Reply #4161 on: April 18, 2017, 09:57:11 AM »
The problem if I understand correctly is that the 2013 line and the 2000s average are not at 13.174 but much higher  :o
Must have been some kind of revision from then to now?

Yes.  On 06 September 2013 there was a change in the data set -- see comment #406.  Unfortunately the descriptive link is broken.  I believe that the change had to do with the handling of the land masks, but Epsen or Wipneus would know much more than I do.

Everything after Sep 2013 seems comparable, stuff before has a different calibrationr

Thanks for the explanation! The thread is a little long to read through to see what happened, easier to ask.  :)

Neven

  • Administrator
  • ASIF Governor
  • *****
  • Posts: 3942
    • View Profile
    • Arctic Sea Ice Blog
Re: IJIS
« Reply #4162 on: April 18, 2017, 10:53:37 AM »
IJIS:

13,069,913 km2(April 17, 2017)down 24,131 km2 and lowest measured for the date.

Shouldn't that be second lowest? In my spreadsheet 2016 was at 13,059,136 on April 17th.
Il faut cultiver notre jardin

Tfisher

  • ASIF Lurker
  • Posts: 7
    • View Profile
Re: IJIS
« Reply #4163 on: April 18, 2017, 03:53:20 PM »
I think when Espen writes "lowest measured for the date" he really means "lowest measured for this day of the year."  The difference is that in a leap year like 2016, March 1 is day number 61 while in a non-leap-year like 2017, March 1 is day number 60. 

Siffy

  • ASIF Citizen
  • Posts: 179
    • View Profile
Re: IJIS
« Reply #4164 on: April 18, 2017, 04:20:24 PM »
IJIS:

13,069,913 km2(April 17, 2017)down 24,131 km2 and lowest measured for the date.

Shouldn't that be second lowest? In my spreadsheet 2016 was at 13,059,136 on April 17th.

Leap year date difference maybe?

Espen

  • ASIF Governor
  • Posts: 3013
    • View Profile
Re: IJIS
« Reply #4165 on: April 19, 2017, 05:26:04 AM »
IJIS:

13,044,495 km2(April 18, 2017)down 25,418 km2 and 2nd lowest measured for the date.
Have a ice day!

Espen

  • ASIF Governor
  • Posts: 3013
    • View Profile
Re: IJIS
« Reply #4166 on: April 20, 2017, 04:54:05 PM »
IJIS:

13,033,695 km2(April 19, 2017)down 18,800 km2 and 2nd lowest measured for the date.
Have a ice day!

Bill Fothergill

  • ASIF Citizen
  • Posts: 272
    • View Profile
Re: IJIS
« Reply #4167 on: April 20, 2017, 06:20:12 PM »
IJIS:

13,033,695 km2(April 19, 2017)down 18,800 km2 and 2nd lowest measured for the date.

That minor drop on the 19th takes the 2017 extent to just below that clocked up by April 23rd 2007. Unless the extent actually rises during the next four days, the number of appearances in the "lowest 3 for the date" category for 2017 will rise from 107 to 111 by the 23rd. Simultaneously, the number of appearances in the "lowest 3" for 2007 will drop from 113 to 110.

By that stage, only 2012 and 2016 will have more appearances in the "lowest 3" - with 171 and 312 respectively.

Espen

  • ASIF Governor
  • Posts: 3013
    • View Profile
Re: IJIS
« Reply #4168 on: April 21, 2017, 05:38:46 AM »
IJIS:

13,000,702 km2(April 20, 2017)down 32,993 km2 and 2nd lowest measured for the date.
Have a ice day!

Espen

  • ASIF Governor
  • Posts: 3013
    • View Profile
Re: IJIS
« Reply #4169 on: April 22, 2017, 10:06:42 AM »
IJIS:

12,933,184 km2(April 21, 2017)down 67,518 km2 and 2nd lowest measured for the date.
Have a ice day!

Shared Humanity

  • ASIF Upper Class
  • Posts: 2014
    • View Profile
Re: IJIS
« Reply #4170 on: April 22, 2017, 04:19:12 PM »
2017 will continue to separate itself from the 2000's average IMHO, much like 2016.

Jim Pettit

  • Global Moderator
  • ASIF Upper Class
  • *****
  • Posts: 1013
    • View Profile
Re: IJIS
« Reply #4171 on: April 23, 2017, 02:57:48 PM »
For those wondering, this was posted a few days back:


Espen

  • ASIF Governor
  • Posts: 3013
    • View Profile
Re: IJIS
« Reply #4172 on: April 25, 2017, 05:32:57 AM »
IJIS:

12,832,850 km2(April 24, 2017)and 2nd lowest measured for the date.
Have a ice day!

solartim27

  • ASIF Citizen
  • Posts: 416
    • View Profile
Re: IJIS
« Reply #4173 on: April 25, 2017, 08:14:05 AM »
: Espen link=topic=230.msg111111#msg111111 (April 24, 2017)and 2[sup
nd[/sup] lowest measured for the date.
A century, and the graph is flat?  Something seems wrong.
FNORD

oren

  • ASIF Upper Class
  • Posts: 1473
    • View Profile
Re: IJIS
« Reply #4174 on: April 25, 2017, 08:46:43 AM »
A century, and the graph is flat?  Something seems wrong.
It's covering 3 days, since IJIS was down.

Bill Fothergill

  • ASIF Citizen
  • Posts: 272
    • View Profile
Re: IJIS
« Reply #4175 on: April 25, 2017, 09:30:28 AM »
A century, and the graph is flat?  Something seems wrong.
It's covering 3 days, since IJIS was down.
As Oren stated, we had a hiatus/pause from April 21 to April 24. The "missing" values can be found on the .csv file

April 22: 12875995
April 23: 12827488
April 24: 12832850

Feeltheburn

  • ASIF Citizen
  • Posts: 109
    • View Profile
Re: IJIS
« Reply #4176 on: April 25, 2017, 02:59:01 PM »
A century, and the graph is flat?  Something seems wrong.

It is consistent with NSIDC which shows melting hiatus the past few days.
Feel The Burn!

seaicesailor

  • Guest
Re: IJIS
« Reply #4177 on: April 25, 2017, 08:33:43 PM »
Last year the Beaufort sea gap kept opening steadily until well entered may 2016, which contributed in part to anomalously low extent. The north of Svalbard was clear-cut clean by mid may while this year is covered by MYI that will be clearing gradually. The timing is different this year too, would be surprised if the curve follows 2016.
To add that Greenland Sea and Barentz have seen import of much thicker ice this year... "good" for extent now, bad for the prospects of ice
Surprisingly even with higher extent Tealight's accumulated albedo potential anomaly is running highest, although very small numbers, still very early in the season
https://sites.google.com/site/cryospherecomputing/warming-potential/graphs
« Last Edit: April 25, 2017, 08:48:25 PM by seaicesailor »

Deeenngee

  • ASIF Lurker
  • Posts: 51
    • View Profile
    • Baddadgags
Re: IJIS
« Reply #4178 on: April 25, 2017, 09:47:31 PM »
An update of my chart showing cumulative days in the bottom 3 for each date. Also a grid view showing the numbers.

2017 has now overtaken 2006, 2007, 2011 and 2015. Unless there are a couple of extended plateaux, I'd be surprised if 2017 spends much time outside the bottom 3 to the end of May.

Finally, an update of my 2017 vs 1990-16 daily range chart, now shifted to April & May.
https://twitter.com/baddadgags

One liners, dad jokes, other jokes; all mine. Please follow for 2 to 3 moderately amusing instances of the above per week, guaranteed.

Ice Shieldz

  • ASIF Citizen
  • Posts: 155
    • View Profile
Re: IJIS
« Reply #4179 on: April 25, 2017, 09:51:39 PM »
Seaicesailor - Graphics down on the home page of Tealight's site.  From his site, I pulled the following graph (albedo derived from NSIDC concentration data) Is this the most relevant graph?

Deeenngee

  • ASIF Lurker
  • Posts: 51
    • View Profile
    • Baddadgags
Re: IJIS
« Reply #4180 on: April 25, 2017, 10:51:12 PM »
One more - this time, 10 year averages.
https://twitter.com/baddadgags

One liners, dad jokes, other jokes; all mine. Please follow for 2 to 3 moderately amusing instances of the above per week, guaranteed.

Deeenngee

  • ASIF Lurker
  • Posts: 51
    • View Profile
    • Baddadgags
Re: IJIS
« Reply #4181 on: April 25, 2017, 10:51:51 PM »
(this time with graph!)
https://twitter.com/baddadgags

One liners, dad jokes, other jokes; all mine. Please follow for 2 to 3 moderately amusing instances of the above per week, guaranteed.

oren

  • ASIF Upper Class
  • Posts: 1473
    • View Profile
Re: IJIS
« Reply #4182 on: April 25, 2017, 11:05:24 PM »
Seaicesailor - Graphics down on the home page of Tealight's site.  From his site, I pulled the following graph (albedo derived from NSIDC concentration data) Is this the most relevant graph?
Yes. The cumulative FDD graph is the most relevant for winter, and the one you posted is the most relevant over the melting season

seaicesailor

  • Guest
Re: IJIS
« Reply #4183 on: April 26, 2017, 12:08:47 AM »
Seaicesailor - Graphics down on the home page of Tealight's site.  From his site, I pulled the following graph (albedo derived from NSIDC concentration data) Is this the most relevant graph?
Yes. The cumulative FDD graph is the most relevant for winter, and the one you posted is the most relevant over the melting season
I think so too. Worth keeping an eye during the season!

Espen

  • ASIF Governor
  • Posts: 3013
    • View Profile
Re: IJIS
« Reply #4184 on: April 26, 2017, 05:25:45 AM »
IJIS:

12,826,358 km2(April 25, 2017)down 6,492 km2 and 2nd lowest measured for the date.
Have a ice day!

Espen

  • ASIF Governor
  • Posts: 3013
    • View Profile
Re: IJIS
« Reply #4185 on: April 27, 2017, 05:25:30 AM »
IJIS:

12,810,275 km2(April 26, 2017)down 16,083 km2 and 2nd lowest measured for the date.
Have a ice day!

Espen

  • ASIF Governor
  • Posts: 3013
    • View Profile
Re: IJIS
« Reply #4186 on: April 28, 2017, 05:28:37 AM »
IJIS:

12,800,339 km2(April 27, 2017)down 9,936 km2 and 2nd lowest measured for the date.
Have a ice day!

Espen

  • ASIF Governor
  • Posts: 3013
    • View Profile
Re: IJIS
« Reply #4187 on: April 29, 2017, 10:00:50 AM »
IJIS:

12,758,153 km2(April 28, 2017)down 42,186 km2 and 2nd lowest measured for the date.
Have a ice day!

Feeltheburn

  • ASIF Citizen
  • Posts: 109
    • View Profile
Re: IJIS
« Reply #4188 on: April 29, 2017, 05:06:57 PM »
IJIS:

12,800,339 km2(April 27, 2017)down 9,936 km2 and 2nd lowest measured for the date.

In know we should take a 5 day average, which I haven't done, but the daily SIE reported by NSIDC his risen (or dropped depending on your point of view) to 4th lowest, being higher than 2016, 2015 and 2006.
Feel The Burn!

magnamentis

  • ASIF Upper Class
  • Posts: 1190
    • View Profile
    • Nexpaq Modular ARA iOS Software Mobile Computing Phones Philosophy Ethics Numerology Mikrocirkulation Vaskular Therapie Gesundheit Blut Gesundheit Schmerzen Multipelsklerose Diabetes Immunsystem Fibromyalgie
Re: IJIS
« Reply #4189 on: April 29, 2017, 11:13:43 PM »
IJIS:

12,800,339 km2(April 27, 2017)down 9,936 km2 and 2nd lowest measured for the date.

In know we should take a 5 day average, which I haven't done, but the daily SIE reported by NSIDC his risen (or dropped depending on your point of view) to 4th lowest, being higher than 2016, 2015 and 2006.

really wondering where you get your stuff each time you post, please at least provide a link or an image because i've not been able to find a raise for a 5 days average or daily values, ready to stand corrected but need proof and then if the raise yo're talking about is a one day event and considering  the higher mobility of fractured and thinner ice, that extent is close to meaningless.

last but not least i wonder where that urge comes from to post things that sound opposite to the obvious direction of developement, even though that key values like volume (only relevant IMO) are down by a huge margin compared to 20th century numbers and as well down compared to last 15 years average and WAY down i have to point out.

i gladly admit that i could not resist to reply even though one probably should not, but that's how i am LOL
http://magnamentis.com
Knowledge, Understanding & Insight Are Among The Best Sources For Personal Freedom & Vitality !

Tor Bejnar

  • ASIF Upper Class
  • Posts: 1479
    • View Profile
Re: IJIS
« Reply #4190 on: April 30, 2017, 12:22:04 AM »
The NSIDC chart (with all years included - called "charctic", for I presume, "cutesy" reasons) indicates 2017 is 2nd lowest in the historical record.  (Is this 5-day average?  I'm sure it is: "NSIDC produces the daily extent values using a five-day trailing mean.") Enlargement of the recent data-filled part of the chart attached, and also yesterday's data info.  Per their request: credit “National Snow and Ice Data Center.” (pale blue line is 2017)[I realize this is OT. sorry]
Arctic ice is healthy for children and other living things.

Bill Fothergill

  • ASIF Citizen
  • Posts: 272
    • View Profile
Re: IJIS
« Reply #4191 on: April 30, 2017, 01:23:25 AM »
... NSIDC charctic ...Is this 5-day average? ...

Yes Rot, Tot, Otr, Rto, Ort, Tro, Tor

What appears on the charctic is the rolling 5-day average of this daily data series...

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/N_seaice_extent_daily_v2.1.csv

(No prizes for guessing what you get if you change the "north" to "south", and the "N_seaice" to "S_seaice" in that url.)

The above url is also the source for Feeltheburn's correct statement that the value on 28th April is the 4th lowest for that date. One can easily pull out the 3 lower instances by using the browser's "Find" functionality.

To quickly highlight just the 28th April dates, search for "04,  28", then start searching bottom upwards. (NOTE: the search string needs two spaces between the comma and the 2)


FatFingeredFothergill

mmghosh

  • ASIF Lurker
  • Posts: 54
    • View Profile
Re: IJIS
« Reply #4192 on: April 30, 2017, 12:04:28 PM »
OTOH, this is the ADS-NIPR thread.  I imagine FTB would like to highlight whatever infrequent "good news" there is.

Shared Humanity

  • ASIF Upper Class
  • Posts: 2014
    • View Profile
Re: IJIS
« Reply #4193 on: April 30, 2017, 08:31:00 PM »
Only 4th lowest is pretty weak tea.     :P

Bill Fothergill

  • ASIF Citizen
  • Posts: 272
    • View Profile
Re: IJIS
« Reply #4194 on: May 01, 2017, 01:59:16 PM »
For those experiencing "cold turkey" whilst ADS is having a little rest...

After spending the 8 days (covering the 22nd to 29th April) languishing in the 13.4xx million sq kms range, the NSIDC single day value plummeted all the way to 13.395 on the 30th.  ;)

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/N_seaice_extent_daily_v2.1.csv

Espen

  • ASIF Governor
  • Posts: 3013
    • View Profile
Re: IJIS
« Reply #4195 on: May 02, 2017, 05:24:01 AM »
IJIS:

12,648,560 km2(May 1, 2017)
« Last Edit: May 02, 2017, 07:57:43 PM by Espen »
Have a ice day!

Lord M Vader

  • ASIF Upper Class
  • Posts: 1085
    • View Profile
Re: IJIS
« Reply #4196 on: May 02, 2017, 07:40:53 AM »
To make it clear: we  are 3rd lowest, behind 2016 and 2006.

pauldry600

  • ASIF Citizen
  • Posts: 145
    • View Profile
    • weathergossip
Re: IJIS
« Reply #4197 on: May 02, 2017, 11:09:41 AM »
I suspect some rapid melt in the next 7 days around greenland

temps well over 0c forecast

Random_Weather

  • ASIF Lurker
  • Posts: 63
    • View Profile
Re: IJIS
« Reply #4198 on: May 02, 2017, 11:20:19 AM »
I suspect some rapid melt in the next 7 days around greenland

temps well over 0c forecast


Same as i, because not only of temp, also on thickness: http://data.seaiceportal.de/maps/smos/n/2017/thumbs_800/thick_n_20170430.png

Bill Fothergill

  • ASIF Citizen
  • Posts: 272
    • View Profile
Re: IJIS
« Reply #4199 on: May 02, 2017, 01:02:19 PM »
I suspect some rapid melt in the next 7 days around greenland

temps well over 0c forecast


Same as i, because not only of temp, also on thickness: http://data.seaiceportal.de/maps/smos/n/2017/thumbs_800/thick_n_20170430.png


It will be interesting to see if this anticipated melting is sufficient to keep 2017 in amongst the "lowest 3 for the day" values.

Here is a variant on Deeenngee's chart at #4178, with data up to, and including, the 1st May (i.e. Day 121).

Tips on interpretation;

Only years with around ~90 (or more) entries in the "lowest 3" are shown.

Generally, each year has 5 columns...
Col 1: status at end of 2015
Col 2: status at end of 2016
Col 3: maximum still possible by end of 2017
Col 4: positions already achieved thus far in 2017 (i.e. "locked")
Col 5: positions held last year between NOW and 31st Dec 2016 (i.e. "vulnerable")

Therefore difference between Col 1 & Col 2 equates to positions lost last year, and the difference between Col 2 & Col 3 equates to positions lost since 1st Jan 2017.