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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #850 on: June 22, 2018, 03:54:31 PM »
NSIDC Total Area  as at 21st June (5 day trailing average) =   8,388,639 km2
This is 211k above the 2010-2017 average on this date.


Total Area loss 51 k, Central Seas 14 k Periphery 12k, Other Seas 25k (Hudson 26k).   

The slow down in June melt is now showing in these 5 day averages. Current day is 41k below the 2010-2017 average area loss.

Analysis of individual seas.

Pacific Side
- The Okhotsk Sea area is 20 k, +1k on the day (It just will not die).
- The Bering Sea area is 3k.    (It also just will not die)
- Chukchi Sea loss 11 k,
- Beaufort Sea gain 16 k
i.e. Pacific side slow - loss or even sometimes a slow gain...

Atlantic Side
- Total area loss of the Baffin, Greenland, and Barents Seas just 14 k,
of which the Baffin loss was 8k and the Barents 4k
- The Laptev Sea area gain 8 k  .
- The Kara Sea area gain 3 k.

CAB
- The Central Arctic Sea loss 13k
- The Canadian Archipelago loss 1 k
- East Siberian Sea loss 2 k

Other seas
- St Lawrence area is up 1 to 3 k,
- Hudson Bay area loss 26 k, area now just below 1990's average - i.e.a bit of catch-up.

Area loss this year to date has followed the 2010-17 average very closely indeed, but is slowing. Individual seas leaders matched by the laggards.
[/quote]
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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #851 on: June 23, 2018, 05:55:21 AM »
Sorry guys. No ADS this weekend…  :P
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Wipneus

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Re: 2018 sea ice area and extent data
« Reply #852 on: June 23, 2018, 08:13:31 AM »
Possible outage(s) with NSIDC as well:

Quote
DMSP F18 to undergo testing late June, early July
June 22, 2018


The Defense Meteorological Satellite Program (DMSP) F18 satellite will be undergoing testing from June 25 to 29 and from July 9 to 12. During this time, data from the Special Sensor Microwave Imager/Sounder (SSMIS) sensor on F18 may have degraded quality or may not be collected. DMSP F18 is the primary sensor that provides NSIDC with near-real-time data for sea ice monitoring (nsidc-0081, the Sea Ice Index, and the Arctic Sea Ice News and Analysis web page). If the data quality does not meet operational standards, NSIDC will remove the resulting sea ice fields or NSIDC may not distribute data from the F18 SSMIS during the test periods.

link

Steven

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Re: 2018 sea ice area and extent data
« Reply #853 on: June 23, 2018, 08:45:06 PM »
Compactness is quite high at the moment:




gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #854 on: June 23, 2018, 09:29:52 PM »
NSIDC Total Area  as at 22nd June (5 day trailing average) =   8,370,055 km2
This is 296k above the 2010-2017 average on this date.

     
Total Area loss a mere 19 k, Central Seas GAIN 12 k Periphery 16k, Other Seas 14k (Hudson 13k).

Crash bang wallop?   

The slow down in June melt is now showing in these 5 day averages. Current day area loss is 85k below the 2010-2017 average area loss.

Analysis of individual seas.

Pacific Side
- The Okhotsk Sea area is 20 k, -1k on the day (It just will not die).
- The Bering Sea area is 3k.    (It also just will not die)
- Chukchi Sea loss 4 k,
- Beaufort Sea loss 1 k
i.e. Pacific side slow - loss or even sometimes a slow gain...

Atlantic Side
- Total area loss of the Baffin, Greenland, and Barents Seas just 16 k,
of which the Baffin loss was 10k and the Barents 4k
- The Laptev Sea area gain 11 k  .
- The Kara Sea area loss 5 k.

CAB
- The Central Arctic Sea gain 5k
- The Canadian Archipelago gain[/b 7 k
- East Siberian Sea loss 1 k

Other seas
- St Lawrence area no change in area at 3 k,
- Hudson Bay area loss 213 k, area now just below 1990's average.

Area loss this year to date has followed the 2010-17 average very closely indeed, but is slowing.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #855 on: June 25, 2018, 10:46:14 PM »
NSIDC Total Area  as at 24 June (5 day trailing average) =    8,344,893 km2
This is 461k above the 2010-2017 average on this date.

     
Total Area loss a mere 9 k, Central Seas GAIN 16 k Periphery 17k, Other Seas 9k

Area loss lowed to a crawl for the last three days.

The slow down in June melt is now showing in these 5 day averages. Current day area loss is approaching 100k below the 2010-2017 average daily area loss.

Analysis of individual seas.

Pacific Side
- The Okhotsk Sea area is 17 k, -2k on the da.
- The Bering Sea area is 3k.
- Chukchi Sea loss 7 k,
- Beaufort Sea gain 4  k
i.e. Pacific side slow - loss or even sometimes a slow gain...

Atlantic Side
- Total area loss of the Baffin, Greenland, and Barents Seas just 17 k,
of which the Baffin loss was 8 k, the Greenland 6k and  the Barents 3k
- The Laptev Sea area gain 7 k  .
- The Kara Sea area loss 13 k.

CAB
- The Central Arctic Sea gain 19k
- The Canadian Archipelago gain 4 k
- East Siberian Sea gain 3 k

Other seas
- St Lawrence area no change in area at 2 k,
- Hudson Bay area loss 7 k, area now just below 1990's average.

Area loss this year to date followed the 2010-17 average very closely indeed, but is slowing to well below average. I will not resist a comment about melting season posts predicting catastrophic loss of Arctic Sea Ice - always just around the corner.

last post for a bit on NSIDC data - they are out of commission for a few days.
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bbr2314

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Re: 2018 sea ice area and extent data
« Reply #856 on: June 25, 2018, 10:50:06 PM »

Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #857 on: June 26, 2018, 06:05:26 AM »
Sorry guys. No ADS this weekend…  :P


ADS NIPR (JAXA) has not come back yet.
I am going to bed, so you can look at:

https://ads.nipr.ac.jp/vishop/#/extent
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

psymmo7

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Re: 2018 sea ice area and extent data
« Reply #858 on: June 26, 2018, 10:10:45 AM »
Does anyone (perhaps someone who understands japanese) have any idea why the JAXA website is still down or know to whom we could address an enquiry?

oren

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Re: 2018 sea ice area and extent data
« Reply #859 on: June 26, 2018, 10:49:26 AM »
Their twitter page can reveal little secrets in English.
Quote
Our service will be stopped from June 22 to 25 by planed electrical  outage for legal inspection.
8:41 PM - 22 Jun 2018
Quote
Now ADS service is down due to system failure from 25th June.
6:54 PM - 25 Jun 2018

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #860 on: June 26, 2018, 11:58:32 AM »
NSIDC Data Outage

Every time DMSP sateliite F18 goes off-line for maintenance I am reminded that the data on which so many of us depend for so much hangs by a single electronic thread.

F18 is the last man standing and I believe is already operating beyond its design life. Thanks to the US Congress "what happens next" is still up in the air.

From a post last November.

Quote
NSIDC DATA - Nearing the end?

https://www.theguardian.com/science/2017/nov/05/donald-trump-accused-blocking-satellite-climate-change-research

It seems that NASA have decided that DMSP satellite F-19 cannot be made operational, and has been abandoned.
DMSP satellite F-20 was destroyed by order of Congress.
The current satellites are already working beyond their shelf-life and the earliest replacement date is 2023.
It is highly likely that NSIDC data will be interrupted temporarily or permanently.

“This is like throwing away the medical records of a sick patient,” said David Gallaher of the National Snow and Ice Data Center in Boulder, Colorado. “Our world is ailing and we have apparently decided to undermine, quite deliberately, the effectiveness of the records on which its recovery might be based. It is criminal.”

However, this criminal act lies not with Trump but at the door of Rep. US Senator Lamar Smith, current chairman of the U.S. House Science, Space and Technology Committee.
He is not standing for re-election next year, and the hurrahs vs eulogies have already started.

http://beta.latimes.com/business/hiltzik/la-fi-hiltzik-lamar-smith-20171103-story.html
https://www.texastribune.org/2017/11/02/lamar-smith-retiring-congress/
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weatherdude88

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Re: 2018 sea ice area and extent data
« Reply #861 on: June 26, 2018, 06:54:16 PM »
The NSIDC northern hemisphere arctic sea ice extent value for 6.25.2018 is 10.241 millions of square kilometers. This places 2018 northern hemisphere sea ice extent in 7th place for the date.

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/

Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #862 on: June 27, 2018, 05:46:55 AM »
ADS-NIPR-JAXA has a server problem…  :-\
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

Neven

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Re: 2018 sea ice area and extent data
« Reply #863 on: June 27, 2018, 10:53:19 AM »
Better than a satellite problem, but still something of a PITA, as I'm curious to see how extent will react to current weather conditions.
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weatherdude88

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Re: 2018 sea ice area and extent data
« Reply #864 on: June 27, 2018, 01:46:00 PM »
The NSIDC northern hemisphere arctic sea ice extent value for 6.26.2018 is 10.297 millions of square kilometers (gain of 56 thousand square kilometers). This places 2018 northern hemisphere sea ice extent in 8th place for the date.

oren

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Re: 2018 sea ice area and extent data
« Reply #865 on: June 27, 2018, 01:47:43 PM »
Thanks for these updates weatherdude.

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Re: 2018 sea ice area and extent data
« Reply #866 on: June 27, 2018, 03:08:30 PM »
Ah, but NSIDC area dropped -256k.  Maybe not so unexpected considering that area is relatively high, now at the 11th lowest for the day.

Drops everywhere, in and outside the Arctic Basin:

Regional Arctic Sea Ice Extent and Area calculated from NSIDC NASA Team concentration data
Date: 2018-06-26 12:00  Values in 1000 km^2

Extent (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4282.5   -5.3  -162.2    935.1   +0.0   +15.1    534.7   -2.0  -154.7
               Kara Sea             Barents Sea           Greenland Sea
   750.0  -15.3   -68.8    134.4  +19.1  -257.9    321.7  +12.2  -272.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   657.2   -4.8   -23.6     23.4  +18.7   +18.1    943.7   -8.1   +61.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   711.8   +2.6    +1.1    500.7   -5.0   +29.9    370.2  -13.8   -94.7
             Bering Sea          Sea of Okhotsk                   Lakes
    32.5  +23.2   -10.2     80.1  +21.2    +7.3    183.9  -35.8   +57.3
          Other regions       Total (ex. lakes)
    19.3  +13.2   +16.0  10297.2  +55.9  -895.6

Area (value, one day change, anomaly):
   Central Arctic Basin       East Siberian Sea              Laptev Sea
  4079.1  -65.4   -37.1    795.9  -22.2   +54.2    358.3   -1.3  -154.7
               Kara Sea             Barents Sea           Greenland Sea
   451.4  -30.7  -143.7     61.1   +1.1  -157.7    206.2   +1.7  -133.1
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
   330.9  -57.2   -83.8      6.4   +5.0    +4.8    506.8  -71.3   -25.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
   489.5   +1.0   -32.2    391.3  -12.5   +34.5    245.5  -19.0  -119.3
             Bering Sea          Sea of Okhotsk                   Lakes
     7.9   +5.0    -4.0     23.2   +6.4    -3.5    105.2   -2.6   +41.4
          Other regions       Total (ex. lakes)
     6.0   +3.4    +4.9   7959.6 -256.1  -796.0


This is also shown in the delta map. Here red/blue pixels indicate that ice concentration goes below/above 15%. Pinkish/blueish colors indicate that concentration changed more than 7% (down/up).

Neven

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Re: 2018 sea ice area and extent data
« Reply #867 on: June 27, 2018, 04:17:52 PM »
Ah, but NSIDC area dropped -256k.

Indeed, and if extent by contrast goes up by 55K, compactness drops by a massive 3 percentage points. May I point out that his melting season is a bit crazy?
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Shared Humanity

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Re: 2018 sea ice area and extent data
« Reply #868 on: June 27, 2018, 04:26:18 PM »
Indeed, and if extent by contrast goes up by 55K, compactness drops by a massive 3 percentage points. May I point out that his melting season is a bit crazy?

It is fascinating. I cannot turn away from watching it and I haven't a clue what is happening or why.

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #869 on: June 27, 2018, 05:17:28 PM »
Why is it that I am stuck offline (apart from a rubbish phone) just when things start to move again?
Hoping to resume this weekend.
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lurkalot

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Re: 2018 sea ice area and extent data
« Reply #870 on: June 27, 2018, 06:14:01 PM »
Charctic shows a loss of 47k not a gain of 56k but maybe I'm looking at 5 day smoothed and weatherdude at single day - or vice versa?

Neven

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Re: 2018 sea ice area and extent data
« Reply #871 on: June 27, 2018, 06:21:14 PM »
Yes, there are differences.
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bbr2314

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Re: 2018 sea ice area and extent data
« Reply #872 on: June 27, 2018, 06:57:53 PM »
The #s for 2018 do not reflect the "reality" due to the abundance of HB / Kara ice. The high latitudes are IMO worst ever.

Dharma Rupa

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Re: 2018 sea ice area and extent data
« Reply #873 on: June 27, 2018, 07:30:20 PM »
Warm ice and clouds.  Interesting combination, and very unpredictable end game.

dnem

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Re: 2018 sea ice area and extent data
« Reply #874 on: June 27, 2018, 08:30:45 PM »
Really interesting and I think indicative of the expected increase in variability and unpredictable behavior as we inch closer to the final collapse of arctic summer ice cover.  Curve fitting or even physical explanations such as more open water leading to cooler, cloudier summers and a "slow transition" will not be useful in predicting the (IMO) unpredictable end game.  This will be apparent within the next at most 10 (and probably less) melt seasons.

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #875 on: June 27, 2018, 09:04:30 PM »
Back in circulation again- I hope (technology permitting)

NSIDC Total Area as at 26 June (5 day trailing average) = 8,252,513 km2
This is 545k above the 2010-2017 average (and only 129k below the 2000's average on this date).

That's a lot of ice. 545k km2 of ice even at an average thickness of 1/2 a metre is 270+ gigatonnes, nearly the average annual volume loss according to PIOMAS.
     
Total Area loss recovered over the two days from a mere 9 k, to 83 k, still 20k below average for the day.
Central Seas 16 k Periphery 35k, Other Seas 19k

Analysis of individual seas.

Pacific Side
- The Okhotsk Sea area is 18 k,
- The Bering Sea area is 4k.
- Chukchi Sea loss 15 k,
- Beaufort Sea loss 2  k
i.e. Pacific side slow - loss or even sometimes a slow gain...

Atlantic Side
- Total area loss of the Baffin, Greenland, and Barents Seas 29 k,
of which the Baffin Sea loss was a high 22 k, the Greenland Sea 6k and  the Barents 2k
- The Laptev Sea area loss 2 k  .
- The Kara Sea area loss 18 k.

CAB
- The Central Arctic Sea loss 2k
- The Canadian Archipelago gain 1 k
- East Siberian Sea gain 2 k

Other seas
- St Lawrence area up at 3 k,
- Hudson Bay area loss 20 k, area now below 1990's average.

Area loss this year to date followed the 2010-17 average very closely indeed, but slowed to well below average since June 10. I again will not resist a comment about melting season posts predicting catastrophic loss of Arctic Sea Ice - always just around the corner.

perhaps on Sunday a good idea to give the area graphs an airing.
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Brigantine

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Re: 2018 sea ice area and extent data
« Reply #876 on: June 28, 2018, 12:38:04 AM »
This is 545k above the 2010-2017 average (and only 129k below the 2000's average on this date).[/b]
That's a lot of ice. 545k km2 of ice even at an average thickness of 1/2 a metre is 270+ gigatonnes, nearly the average annual volume loss according to PIOMAS.

Except it isn't necessarily a difference between 0.5m thick ice and seawater. More likely much of the difference is where there is dry ice* or snowed-over or frozen over melt ponds, in the place of meltwater.

(meltwater having the same appearance to the satellite/algorithm as seawater so not counting towards ice area, even if there's 0.5+m of ice underneath.)

*- here meaning water 100% in the solid phase, not to be confused with CO2 "dry ice"
« Last Edit: June 28, 2018, 12:43:08 AM by Brigantine »

DavidR

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Re: 2018 sea ice area and extent data
« Reply #877 on: June 28, 2018, 06:01:26 AM »
NSIDC Total Area as at 26 June (5 day trailing average) = 8,252,513 km2
This is 545k above the 2010-2017 average (and only 129k below the 2000's average on this date).

That's a lot of ice. 545k km2 of ice even at an average thickness of 1/2 a metre is 270+ gigatonnes, nearly the average annual volume loss according to PIOMAS.
The average loss from PIOMAS over the past 40 years is 16,900 km^3. 545K km^2 of area half a meter thick is only 272 km^3 and represents only 1.6% of the average loss. 

The way the Beaufort is looking today, light blue rather than white or dark blue, I  suspect that a lot of that extra area isn't very thick at all. Also that other parts of the Arctic are not as thick as usual.  With  the ice as broken up as it seems to be I have the feeling that the water in the CAB is seeing a lot more insolation than usual which may lead to the same rapid late melt out that we saw in 2016. 
Toto, I've a feeling we're not in Kansas anymore

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #878 on: June 28, 2018, 12:25:10 PM »
NSIDC Total Area as at 26 June (5 day trailing average) = 8,252,513 km2
This is 545k above the 2010-2017 average (and only 129k below the 2000's average on this date).

That's a lot of ice. 545k km2 of ice even at an average thickness of 1/2 a metre is 270+ gigatonnes, nearly the average annual volume loss according to PIOMAS.
The average loss from PIOMAS over the past 40 years is 16,900 km^3. 545K km^2 of area half a meter thick is only 272 km^3 and represents only 1.6% of the average loss. 

I perhaps was unclear as to what I meant by "annual average loss". here is a quote  from the Polar Science Center

"To melt the additional 280 km3 of sea ice, the amount we have have been losing on an annual basis based on PIOMAS calculations, it takes roughly 8.6 x 10^19 J or 86% of U.S. energy consumption."

Also, I was not saying the average thickness of the ice that has not melted compared with the average is 50 cms; just saying that IF it was, the current melting season is 270 gt behind the curve as at the end of June.
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Wipneus

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Re: 2018 sea ice area and extent data
« Reply #879 on: June 28, 2018, 02:51:57 PM »
The current NSIDC values are in all likeliness wrong , drop in area -750k. See also the delta map for the mess.

I expect a correction or withdrawal of the data.

RikW

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Re: 2018 sea ice area and extent data
« Reply #880 on: June 28, 2018, 03:10:47 PM »
or we have a real cliff ;)

This is the first time I remember seeing such a strange result, does it happen often?

Wipneus

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Re: 2018 sea ice area and extent data
« Reply #881 on: June 28, 2018, 03:16:47 PM »
or we have a real cliff ;)

This is the first time I remember seeing such a strange result, does it happen often?

Oh, I forgot to mention this:
https://forum.arctic-sea-ice.net/index.php/topic,2223.msg160176.html#msg160176

which, I think, is the real reason.

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Re: 2018 sea ice area and extent data
« Reply #882 on: June 28, 2018, 03:27:34 PM »
Here's a rough attempt to "predict" the missing JAXA values, based on the recent JAXA history plus the subsequent NSIDC extent data (up to 26 June, so not including today's presumably erroneous value):

22 June: 9.95
23 June: 9.87
24 June: 9.84
25 June: 9.80
26 June: 9.82

Disclaimer -- I did that hastily, and a more careful approach would probably give better predictions.  But I didn't have time for a more careful method, so this will do for now....

oren

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Re: 2018 sea ice area and extent data
« Reply #883 on: June 28, 2018, 03:40:09 PM »
Thanks Ned. I do think a better aporoximation would be by taking UH AMSR2 numbers whch I suspect would have lower results, but I am away from my PC and  cannot do the analysis.

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Re: 2018 sea ice area and extent data
« Reply #884 on: June 28, 2018, 04:20:55 PM »
That seems extremely important.  Maybe it would be better for them to suspend their publication of data during testing, so as not to produce misleading information that needs to be corrected later?  And avoid the confusions that tend to proliferate as a result?


Oh, I forgot to mention this:
https://forum.arctic-sea-ice.net/index.php/topic,2223.msg160176.html#msg160176

which, I think, is the real reason.

Ned W

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Re: 2018 sea ice area and extent data
« Reply #885 on: June 28, 2018, 05:01:10 PM »
Thanks Ned. I do think a better aporoximation would be by taking UH AMSR2 numbers whch I suspect would have lower results, but I am away from my PC and  cannot do the analysis.
I have zero time to be doing this, but you have provoked me into doing it anyway  ;)

DateJaxa(Avg)Jaxa(NSIDC)Jaxa(Bremen)
22 June9.929.959.94
23 June9.859.879.87
24 June9.769.849.82
25 June9.699.809.81
26 June9.619.829.73
27 June9.53n/a9.64

All three columns of data are predictions for the missing days of JAXA extent:
First = based on last reported value and average rate of decline on this date (2007-2017)
Second = based on last reported value and NSIDC
Third = based on last reported value and Uni Bremen


oren

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Re: 2018 sea ice area and extent data
« Reply #886 on: June 28, 2018, 07:19:37 PM »
Thanks again. Superb!

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Re: 2018 sea ice area and extent data
« Reply #887 on: June 28, 2018, 07:58:18 PM »
The current NSIDC values are in all likeliness wrong , drop in area -750k. See also the delta map for the mess.

I expect a correction or withdrawal of the data.
We did have something like a week of compaction, wind,waves and low levels moisture blowing into that area,  followed by the reverse for the last few days. Is it possible that it may have expanded into the threshold where gaps between floes cross the threshold where they are noticed by the sensors? SMOS seem to be showing a similar thing. And where I find a few rare gaps in the cloud and fog there it seems to be a field of floes dispersed in open water. It could be errors on both sides of the temporal range?
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Re: 2018 sea ice area and extent data
« Reply #888 on: June 28, 2018, 09:03:53 PM »
Quote from: Wipneus on Today at 08:51:57 AM

It looks more like a giant alien spider (8 legs - or maybe it's a ) sitting on the North Pole - poor Santa.  (I'm glad I'm not purple!)
Arctic ice is healthy for children and other living things.

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Re: 2018 sea ice area and extent data
« Reply #889 on: June 29, 2018, 12:35:36 AM »
The current NSIDC values are in all likeliness wrong , drop in area -750k. See also the delta map for the mess.

I expect a correction or withdrawal of the data.

As long as there's no correction, compactness dropped 6 percentage points, but not quite enough to go lowest on record (71.2% vs 2007's 71.1%).  ;)
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oren

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Re: 2018 sea ice area and extent data
« Reply #890 on: June 29, 2018, 07:28:54 AM »
Surely the data is wrong? The artifacts are clearly visible in Wipneus' map.  ???

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Re: 2018 sea ice area and extent data
« Reply #891 on: June 29, 2018, 09:05:31 AM »
Of course it's wrong. I just thought it was funny to show what the effect on compactness was, especially given that it dropped to almost lowest on record (difference 0.1%). That's why I labelled the graph 'NSIDC data error'. Has it been seized upon by climate risk deniers yet to show how we alarmists have gone nuts?  ;)
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Re: 2018 sea ice area and extent data
« Reply #892 on: June 29, 2018, 09:13:52 AM »
Of course it's wrong. I just thought it was funny to show what the effect on compactness was, especially given that it dropped to almost lowest on record (difference 0.1%). That's why I labelled the graph 'NSIDC data error'. Has it been seized upon by climate risk deniers yet to show how we alarmists have gone nuts?  ;)
Perhaps its been wrong for the past  two  weeks and now we are getting the correction  ;)

Maybe that's why they  were checking the satellite.
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Re: 2018 sea ice area and extent data
« Reply #893 on: June 29, 2018, 09:24:13 AM »
Yes, that's definitely a possibility, although the slowdown also appeared in AMSR2 data. We'll see what happens when everything comes on line again. Bad time of the year for both ADS-NIPR and NSIDC dropping out. But patience is a virtue.
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oren

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Re: 2018 sea ice area and extent data
« Reply #894 on: June 29, 2018, 09:51:36 AM »
My patience with JAXA wears thin, and my sense of humor failed. Sorry Neven I didn't notice the chart label...

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Re: 2018 sea ice area and extent data
« Reply #895 on: June 29, 2018, 12:26:33 PM »
Fed up waiting on JAXA too

I reckon Ill look again when it is 4.5m on September 9th 2018

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Re: 2018 sea ice area and extent data
« Reply #896 on: June 29, 2018, 01:44:53 PM »
The NSIDC northern hemisphere arctic sea ice extent value for 6.28.2018 is 10.031 millions of square kilometers. This places 2018 northern hemisphere sea ice extent in 8th place for the date.

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/

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Re: 2018 sea ice area and extent data
« Reply #897 on: June 29, 2018, 02:26:49 PM »
My patience with JAXA wears thin ...
For now I've switched to looking at Uni Bremen's AMSR2 extent.  It's not a perfect analogue for JAXA.   During the winter UB extent is about 600k greater than JAXA, and during the summer that difference drops to around 200k.  So during June it tends to show larger daily decreases than JAXA does, in order to make up  most of that 400k difference.

Having said that, here are the last week's daily AMSR2 extent decreases via UB:

21 June: 121k
22 June: 57k
23 June: 95k
24 June: 63k
25 June: 05k
26 June: 87k
27 June: 113k

Or taking into account the fact that at this time of year, the UB decreases are about 8k to 6k bigger than JAXA decreases, here are the UB daily decreases modified to be more JAXA-ish:

21 June: 113k
22 June: 49k
23 June: 87k
24 June: 56k
25 June: -02k (increase)
26 June: 80k
27 June: 107k




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Re: 2018 sea ice area and extent data
« Reply #898 on: June 29, 2018, 03:20:24 PM »
NSIDC Total Area as at 28 June (5 day trailing average) =  7,848,090 km2

I attach the data without commentary because:-

Is the data good or bad ?
[/b]
Remember this is the 5 day trailing average from the NSIDC regional data spreadsheet in "sea ice tools"
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Re: 2018 sea ice area and extent data
« Reply #899 on: June 29, 2018, 03:36:47 PM »
Yesterday's data (ice date 2018-06-27) has not been corrected. Today's data (ice date 2018-06-28) looks much better with a jump in area of +471k.

Is the data good or bad? I am not sure, attached is a delta of two days skipping the obvious faulty 27th.