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magnamentis

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Re: 2018 sea ice area and extent data
« Reply #900 on: June 29, 2018, 07:11:28 PM »
Fed up waiting on JAXA too

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

and felt it happens always when things are most interesting, this could be a subjective impression but still, unfortunately didn't write down the dates but always when key events unfold or final seasonal results are approaching we are without data.

BTW i was thinking whether to buy a few guys a webcam. one after the other drops out and is not replaces in most cases. no buoy-cams no webcams a pitty.

does anyone know the guy in kimmirut perhaps i can send him a new one, at least if he wasn't using a multi-thousand dollar equipment LOL

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #901 on: June 29, 2018, 07:32:49 PM »
Fed up waiting on JAXA too

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

and felt it happens always when things are most interesting, this could be a subjective impression but still, unfortunately didn't write down the dates but always when key events unfold or final seasonal results are approaching we are without data.


Below is why I get the shivers every time the satellites go into testing mode.
Things not any better since the article was published last year?
Note the reference to JAXA below

https://www.scientificamerican.com/article/ageing-satellites-put-crucial-sea-ice-climate-record-at-risk/

Ageing Satellites Put Crucial Sea Ice Climate Record at Risk
Scientists scramble to avert disruption to dataset that has tracked polar ice since the late 1970s

By Alexandra Witze, Nature magazine on October 27, 2017

Quote
Scientists all over the world rely on the sea-ice record compiled by the US National Snow and Ice Data Center (NSIDC) in Boulder, Colorado. But the US military satellites that collect the data, by measuring ice extent using microwave sensors, are approaching the end of their lives. Three are still working but ageing, and their intended successor started experiencing glitches in 2016, before conking out for good this month. The next possible replacement won't launch until at least the early 2020s.

That means the most complete and most scientifically significant sea-ice record is at risk of breaking. Any gap in satellite coverage is not just a short-term problem: it would compromise future research, because scientists would not be able to accurately compare observations made before the gap with those from afterward.....

Centre analysts have begun testing the inclusion of sea-ice data from a Japanese satellite, but that spacecraft—designed to last five years—is now five years old. Experts looking to avert the looming gap will gather to debate other options, including the potential use of data from a Chinese satellite, in December, at a meeting of the American Geophysical Union in New Orleans, Louisiana.
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Pagophilus

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Re: 2018 sea ice area and extent data
« Reply #902 on: June 29, 2018, 11:35:15 PM »
I tend to forget about this.   For the Earth, this would be like going partially blind when in the middle of a challenging and exposed trail. 

Below is why I get the shivers every time the satellites go into testing mode.
Things not any better since the article was published last year?
Note the reference to JAXA below

https://www.scientificamerican.com/article/ageing-satellites-put-crucial-sea-ice-climate-record-at-risk/
You may delay, but time will not.   Benjamin Franklin.

FishOutofWater

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Re: 2018 sea ice area and extent data
« Reply #903 on: June 30, 2018, 12:00:19 AM »
Republicans in the U.S. congress ordered the already built follow on satellite destroyed to intentionally blind us in the Arctic and berated the U.S. military for building and storing the satellite. What those people have done on climate is a crime against future generations. Of course, U.S. law allows crimes against future generations, so no one can be punished.

It's as if they put sticks in our eyes and blinded us because they didn't like what we were seeing.

Ned W

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Re: 2018 sea ice area and extent data
« Reply #904 on: June 30, 2018, 02:23:10 AM »
Republicans in the U.S. congress ordered the already built follow on satellite destroyed to intentionally blind us in the Arctic and berated the U.S. military for building and storing the satellite.

No, actually.  The story behind DMSP-20 is much more complicated and less conspiratorial than that, and the decision to cancel it had basically nothing to do with the Arctic.

DMSP-20 was built in the mid-1990s, had been in (expensive) storage for two decades, and was both ageing and technologically obsolescent.  The cost to launch it would be high, and many people were debating whether it was worth it.  An Air Force study in the summer of 2014 recommended against launching DMSP-20, keeping it in storage was running $40 million per year, and every additional year made it more likely that something would go wrong if it were launched. 

The DMSP constellation was not intended for monitoring Arctic sea ice, it was intended to provide support for weather forecasting by the US Air Force.  The program was not planned to be perpetual and it had been assumed that "something else" would replace the F-series satellites after DMSP-20.  First that "something else" was going to be a joint military/civilian mission (NPOESS), then the military part got moved to DWSS (Defense Weather Satellite System), then that got killed and replaced by something called WSF-M. 

There are lots of angles to this story we could talk about.  One of them is a longstanding argument within the US earth observation satellite industry about the relative merits of building large expensive multi-purpose systems vs smaller, lighter, cheaper platforms.  Both approaches have been tried and both have had their problems (ICESat GLAS was an example of what happens when the faster, cheaper approach turns out not to also be "better"). 

Another and related angle is that since the end of the 1990s the Bush and then Obama administrations waffled back and forth repeatedly on how to move forward with ALL the US earth observation satellite programs.  In the early 2000s the Bush administration was gripped with a mania for "privatization" of the nation's EO assets and wasted years going down a road (privatize some systems, reorganize others) that turned out to be a complete dead end.  More than a decade ago Bush's science advisor admitted to me that he knew that yes, in retrospect they had basically screwed up and wasted critical time, given that the US government process for developing and building new satellites is insanely slow and sclerotic.

Yet another strand to this fiasco is a total lack of understanding by policymakers (in the White House and in Congress) of the differences among different types of EO systems and why those differences matter.  Former students of mine now working at NASA are tearing their hair out trying to justify why they have to spend hundreds of millions to build and launch a handful of extremely complex systems when a private company (Planet Labs) can build (and pay someone to launch) 200 tiny cubesats for a fraction of the cost.  There are actually reasonable answers to that question but it takes a lot of bringing people up to speed before they can understand the answers, and in order to shepherd a satellite through the decade-plus-long development process you keep needing to explain the issues over and over again to generation after generation of White House staff and Congressional fact-finders. 

I could go on and on about this.  Yes, the US government's (mis)management of its earth observation satellite programs has often been infuriating and fiascos abound.  Yes, Congress keeps going back to the idea that we could save money by just buying data from someone else, and every time someone comes up with that idea it wreaks massive havoc on all the future plans. 

But no, Congress did not kill DMSP-20 to "intentionally blind us in the Arctic".  All of us here on ASIF are rather obsessed with the Arctic but that was absolutely not a factor in the decisionmaking process. 


Reallybigbunny

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Re: 2018 sea ice area and extent data
« Reply #905 on: June 30, 2018, 02:44:08 AM »
NASA is due to send up ICESat - 2 in a few weeks, I wander if this will provide a clearer picture regarding sea ice area and extent data...

After launch, the fast-firing laser and sensitive detectors aboard ICESat-2 will allow it to collect precise measurements of Earth’s height. The mission is designed to focus on changes in the ice sheets and sea ice in Antarctica and the Arctic, where warming temperatures are having dramatic effects. The satellite will track the changes in these polar regions and around the globe.

Launch is scheduled for Sept. 12, 2018


For more information on ICESat-2, visit: https://icesat-2.gsfc.nasa.gov/

For updates on ICESat-2 and its Delta II at Vandenberg, visit: https://blogs.nasa.gov/icesat2/

For more information about NASA launches, visit: https://www.nasa.gov/centers/kennedy/launchingrockets/index.html

FishOutofWater

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Re: 2018 sea ice area and extent data
« Reply #906 on: June 30, 2018, 03:04:44 AM »
Thanks, Ned W for your insight and expertise on the satellite issue. I am aware of the arguments for smaller and cheaper satellites. I am aware of the limitations of this series of military satellites. I am aware these satellites weren't developed to monitor sea ice.

I am also aware of other uses you didn't mention. This series of satellites was very useful for hurricane forecasting. The microwave imager sees through the high cloud overcast into the developing eyes of hurricanes. I have personally used information derived from these satellites by CIMSS to predict rapid intensification of hurricanes successfully. The NHC and JTWC use the derived data on a regular basis for hurricanes with eyes that can only be seen by microwave sensing.

I didn't come up with the theory that this was malicious destruction based on internet rumor, fake news, or misinterpretation. I read the transcript of the congressional meeting with the DoD representative. That particular congressman viciously attacked the DoD spokesman. He has a record of attacking climate science. He led the charge to destroy the DMSP satellite. He was angry that the NSIDC made a case for keeping it to monitor sea ice decline.

https://www.dailykos.com/stories/2017/9/6/1696633/-Alabama-Republican-Rep-Rogers-DESTROYED-Key-Hurricane-Monitoring-Satellite

Ned W

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Re: 2018 sea ice area and extent data
« Reply #907 on: June 30, 2018, 03:56:30 AM »
Yes, there are other uses for the DMSP satellites, but Congress has always had trouble seeing it as more than a USAF program and has generally focused on that. 

DMSP-20 had been on and off the chopping block for years before that hearing.  Of course Rep Rogers wouldn't respond positively to pleas that it was needed to study Arctic sea ice, but that is not the reason that it was canceled.

I'm also not arguing for "smaller and cheaper satellites" exactly.  It's a lot more complicated than that and hard to sum up easily -- as I pointed out above, the wiring failures on the ICESat-1 lasers were a consequence of trying to build it "smaller and cheaper".  But it's extremely hard to justify keeping a heavy (i.e., expensive-to-launch) satellite on mothballs for 20+ years. 

In general, Congresses and White House staff of both parties have really had trouble understanding how the US earth observation satellite program works and how well-intentioned but bad decisions on their part keep screwing it up.  This is only the latest instance in a long sordid history going back to Reagan's attempt to privatize the entire constellation of meteorological satellites back in the 1980s. 

I wish that DMSP-20 were launched, though I understand both sides of the debate that raged over that question and that long predated Rep Rogers's involvement.  Even better would have been to not screw up plans for the follow-on mission by changing horses in midstream again and again. 

Ned W

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Re: 2018 sea ice area and extent data
« Reply #908 on: June 30, 2018, 05:01:15 AM »
In general, Congresses and White House staff of both parties have really had trouble understanding ... 
Should have noted that Al Gore was a notable exception to this rule.  In the alternate universe where Gore became President in 2001, the USA in 2018 has a much stronger and better developed earth observation satellite program.

OK, sorry for wandering so far off topic.  Back to the ice.

Feeltheburn

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Re: 2018 sea ice area and extent data
« Reply #909 on: June 30, 2018, 05:16:41 AM »
Compactness is quite high at the moment:





Where do you find this information? I made a few observations and guesses a month ago based on the DMI modeled ice thickness that melting would be slow. Compactness as shown on DMI map suggested melting around the edges, followed by a slowdown.
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oren

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Re: 2018 sea ice area and extent data
« Reply #910 on: June 30, 2018, 06:15:51 AM »
Great. Back to JAXA/ADS. Extent for June 30th is...???  >:( :(

Neven

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Re: 2018 sea ice area and extent data
« Reply #911 on: June 30, 2018, 12:35:36 PM »
Where do you find this information? I made a few observations and guesses a month ago based on the DMI modeled ice thickness that melting would be slow. Compactness as shown on DMI map suggested melting around the edges, followed by a slowdown.

The first graph comes from Wipneus' website somewhere (Arctische Pinguin). The second one is made by Steve and relies on NSIDC extent and area data. If you divide area by extent you get an idea of how much open water is within the ice pack (either real open water or melt ponds), in other words: compactness.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #912 on: June 30, 2018, 02:38:12 PM »
ASSUMES THE DATA IS GOOD.
No messages on NSIDC to say otherwise.

If the data is good, the June Cliff started 3 days ago - i.e. in June (just).

NSIDC Total Area as at 29 June (5 day trailing average) =  7,690,066 km2
This is now down to 319k above the 2010-2017 average


Total Area loss 158,017    
Central Seas 121 k Periphery 13k, Other Seas 25k


Analysis of individual seas.

Pacific Side
- The Okhotsk Sea area is 18 k,
- The Bering Sea area is 7k.
- Chukchi Sea loss 22 k,
- Beaufort Sea loss 33  k
i.e. Pacific side loss accelerating.

Atlantic Side
- Total area loss of the Baffin, Greenland, and Barents Seas 13 k,
of which the Baffin Sea loss was a high 14 k, the Greenland Sea gain 2k,and  the Barents loss 1k
- The Kara Sea area loss 22 k.
- The Laptev Sea area loss 11 k  .

CAB
- The Central Arctic Sea loss 30k
- The Canadian Archipelago gain 1 k
- East Siberian Sea gain 4 k

Other seas
- St Lawrence area at 3 k,
- Hudson Bay area loss 25 k, area now below 1990's average.
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Stephan

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Re: 2018 sea ice area and extent data
« Reply #913 on: June 30, 2018, 05:49:17 PM »
I wonder where that Bering ice is as both NOAA as well as climate reanalyzer show water temperatures above +4-+6°C and SST anomalies between +3 and more than +6°C. Is that really ice what they detect? The same is almost true for the Okhtsk Sea (maybe just in the SW-most corner some ice could have survived...)
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #914 on: June 30, 2018, 06:03:45 PM »
I wonder where that Bering ice is as both NOAA as well as climate reanalyzer show water temperatures above +4-+6°C and SST anomalies between +3 and more than +6°C. Is that really ice what they detect? The same is almost true for the Okhtsk Sea (maybe just in the SW-most corner some ice could have survived...)
Click on the attached image and wander around the fringes.
You will see little bits of sea ice in nooks and crannies all over the place.

Local winds and currents may have piled up sea ice into these sheltered places + local ocean currents bringing up colder water, and thus take longer to finally expire.

It is why on my percentage area graphs I chose 5% of maximum to determine ice-free day numbers for each sea.

Or maybe Oren is right (see next post) or maybe we are both right.

https://nsidc.org/data/seaice_index/images/daily_images/N_daily_concentration_hires.png
« Last Edit: June 30, 2018, 06:09:41 PM by gerontocrat »
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oren

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Re: 2018 sea ice area and extent data
« Reply #915 on: June 30, 2018, 06:05:21 PM »
NSIDC often see coastal ice that is really non-existent. It usually winks on and off.
Check out Uni Hamburg AMSR2 3.125km maps, I would expect this ice doesn't appear there. Even better, one of Wipneus' Home Brew maps/animations, as he filters out the false detections by various algorithms.

Alexander555

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Re: 2018 sea ice area and extent data
« Reply #916 on: June 30, 2018, 08:51:39 PM »
Looks like the thick ice in the ESS is going to take a hit in a couple days.

DavidR

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Re: 2018 sea ice area and extent data
« Reply #917 on: July 01, 2018, 06:42:18 AM »
JAXA links are now throwing up their twitter feed. Not a tweet  since 25/6 but perhaps news is on the way. The feed says they  had a system failure on the 25th but nothing more.

https://twitter.com/ADS_NIPR/status/1011427490932244480
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #918 on: July 01, 2018, 02:05:55 PM »
ASSUMES THE DATA IS GOOD.
No messages on NSIDC to say otherwise.

If the data is good, the June Cliff started 4 days ago - i.e. in June (just).

NSIDC Total Area as at 30 June (5 day trailing average) =   7,546,287  km2
This is down to 262k above the 2010-2017 average


Total Area loss 144K    
Central Seas 113 k Periphery 12k, Other Seas 19k
 

Analysis of individual seas.

Pacific Side
- The Okhotsk Sea area is 17 k,
- The Bering Sea area is 7k.
- Chukchi Sea loss 13 k,
- Beaufort Sea loss 31  k
i.e. Pacific side loss accelerating.

Atlantic Side
- Total area loss of the Baffin, Greenland, and Barents Seas 13 k,
of which the Baffin Sea loss was 12 k, the Greenland Sea gain 2k,and  the Barents loss 2k
- The Kara Sea area loss 20 k.
- The Laptev Sea area loss 17 k  .

CAB
- The Central Arctic Sea loss 28k
- The Canadian Archipelago gain 5 k
- East Siberian Sea loss 9 k

Other seas
- St Lawrence area at 3 k,
- Hudson Bay area loss 18 k, area now below 1990's average.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #919 on: July 01, 2018, 04:23:11 PM »
Area graphs as at 30 June -derived from NSIDC Regional Sea Data 5 Day Trailing Average

1st 4 Graphs attached below.
PACIFIC END
Bering Sea.
The question is for me - will the low winter maximum and early melt mean late 2018 re-freeze will be delayed and winter sea ice increase even less ?

Chukchi Sea.
Early melt giving area well below 2010's average area, followed by June slowdown, followed by late June accelerated melt giving below 2010's average area again.

Beaufort Sea
Mid-June strong growth in area followed by strong melt in late June, but area now at 1990's average.

East Siberian Sea
Area still well above 1980's average.
"Para a Causa do Povo a Luta Continua!"
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #920 on: July 01, 2018, 04:50:18 PM »
Area graphs as at 30 June -derived from NSIDC Regional Sea Data 5 Day Trailing Average

Graphs 5 to 7 attached below.

Atlantic Seas (1)

Baffin Sea
Despite cold temperatures, and "snowmageddon" in NE Canada, steady melting in the Baffin Sea - area now just above 2000's average.

Greenland Sea.
Area extremely low. How much is due to year by year reduction in Fram Export? Current low north of Greenland may be upping export a bit, hence recent blip upwards in area. Waiting for Wipneus' fram export graph for June to match against Greenland Sea area change.

Barents Sea
After a surprisingly high March maximum, strong melt has brought area back to the 2010's average. Melt to near zero area should be completed this month.
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bbr2314

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Re: 2018 sea ice area and extent data
« Reply #921 on: July 01, 2018, 05:00:52 PM »
Area graphs as at 30 June -derived from NSIDC Regional Sea Data 5 Day Trailing Average

Graphs 5 to 7 attached below.

Can you do Hudson Bay and Okhotsk please  ;D

I know Okhotsk is all gone but curious to see how early vs. other decades.

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #922 on: July 01, 2018, 05:01:19 PM »
Area graphs as at 30 June -derived from NSIDC Regional Sea Data 5 Day Trailing Average

Graphs 8 and 9 attached below.

Atlantic Seas (2)

Kara Sea
Maximum area was at 1980's average or above. Since late May strong melt has brought area approaching 2010's average

Laptev Sea.
Despite two strong hiccups in melt, area is well below the 201's average.
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #923 on: July 01, 2018, 05:02:19 PM »
Area graphs as at 30 June -derived from NSIDC Regional Sea Data 5 Day Trailing Average

Graphs 5 to 7 attached below.

Can you do Hudson Bay and Okhotsk please  ;D

I know Okhotsk is all gone but curious to see how early vs. other decades.

wait small - (pidgin). Ah, the impatience of youth
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #924 on: July 01, 2018, 05:17:11 PM »
Area graphs as at 30 June -derived from NSIDC Regional Sea Data 5 Day Trailing Average

Graphs 10 and 11 attached below.

Central Arctic

Canadian Archipelago
Melt currently stalled, but area still below 2010's average
BUT, this seems to be a normal occurrence at this time of year.

Central Arctic Sea
The same remarks apply, i.e.
Melt currently stalled, but area still below 2010's average
BUT, this seems to be a normal occurrence at this time of year.
« Last Edit: July 01, 2018, 05:23:11 PM by gerontocrat »
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #925 on: July 01, 2018, 05:35:53 PM »
Area graphs as at 30 June -derived from NSIDC Regional Sea Data 5 Day Trailing Average

Graphs 12, 13 and 14 attached below.

Seas with little direct contact with or influence on the Arctic Ocean
Hudson Bay
The persistent cold in NE Canada delayed melt, but since June melt has closely followed the 1990's average graph line.
Of note is that for all years the minimum is reached at the same date within a week or two

Okhotsk Sea
It was very cold there for a long time this spring (and may have helped to accelerate the melt in the Bering Sea.
Despite a high late maximum and late melting start, by early May area was below the 2010's average.

St Lawrence
Also very cold there in the spring.
A high maximum followed by a catastrophic drop in area.
Of note is that final melt happens at the same time for all years - at about the first of June

This exercise is too much like hard work - not to be done very often
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Neven

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Re: 2018 sea ice area and extent data
« Reply #926 on: July 01, 2018, 05:37:06 PM »
Assuming NSIDC data is correct, and having fixed the obvious outlier (by dividing the two-day drop in two), compactness has dropped quite a bit, reaching the middle of the pack:
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Feeltheburn

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Re: 2018 sea ice area and extent data
« Reply #927 on: July 01, 2018, 09:57:13 PM »
Graphs are visually appealing, but sometimes raw data are also illustrative. I miss Espen's simple presentation of arctic sea extent data. To that end, here is the NSIDC arctic ice extent data for 30 June 2018 in descending order (for historical context). Interesting, ice extent in 2018 is barely lower than 2001 and 2005 on 30-06-18.

2010 - 9.257
2016 - 9.334
2012 - 9.335
2017 - 9.421
2011 - 9.532
2014 - 9.617
2006 - 9.820
2018 - 9.939
2007 - 9.952
2015 - 10.008
2013 - 10.015
2008 - 10.199
2005 - 10.211
2001 - 10.297
2003 - 10.624
1995 - 10.630
2002 - 10.767
2004 - 10.814




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Neven

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Re: 2018 sea ice area and extent data
« Reply #928 on: July 01, 2018, 11:56:09 PM »
Interesting, ice extent in 2018 is barely lower than 2001 and 2005 on 30-06-18.

Even more interesting is the explanation for why this is so, and what it means. But my guess is you're not really interested.  ::)
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oren

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Re: 2018 sea ice area and extent data
« Reply #929 on: July 02, 2018, 12:26:19 AM »
FTB, did you perhaps mix 2008 and 2018 in your textual analysis?

FishOutofWater

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Re: 2018 sea ice area and extent data
« Reply #930 on: July 02, 2018, 04:28:32 AM »
Good news from Japan. They are finally making progress at restoring the ADS server.

https://twitter.com/ADS_NIPR/status/1013577603247034368

CameraMan

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Re: 2018 sea ice area and extent data
« Reply #931 on: July 02, 2018, 05:33:58 AM »
Interesting, ice extent in 2018 is barely lower than 2001 and 2005 on 30-06-18.
Which says more about the limitations of extent as a meaningful gauge of overall ice condition going into summer than it does about this year vs others.  Consider where the ice is, condition, and likely weather ahead -- I wouldn't make too much of daily numbers, especially extent.   

DavidR

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Re: 2018 sea ice area and extent data
« Reply #932 on: July 02, 2018, 06:54:24 AM »
Interesting, ice extent in 2018 is barely lower than 2001 and 2005 on 30-06-18.
Which says more about the limitations of extent as a meaningful gauge of overall ice condition going into summer than it does about this year vs others.  Consider where the ice is, condition, and likely weather ahead -- I wouldn't make too much of daily numbers, especially extent.
Another way of looking at this is that both 2001 and 2005 were record lows for June 30th and 2018 is a few hundred thousand  km^2 below both of them on this date despite having a much bigger extent than 6 of the past 10 years. 

There is also the point that the average decline from this point has increased by about 500K km^2 since 2001 and is largely unrelated to the extent on this date.
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DavidR

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Re: 2018 sea ice area and extent data
« Reply #933 on: July 02, 2018, 10:44:31 AM »
JAXA is back up. July 1st extent is 9,282,553 km^2 putting it 461K behind the record low for that day. It is in 8th place 276K behind 6th. 

The June decline was just 1,459,260 making it the lowest since 2015  and the third lowest in the Jaxa record since 2003.
« Last Edit: July 02, 2018, 10:50:11 AM by DavidR »
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gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #934 on: July 02, 2018, 11:43:31 AM »
JAXA Extent 9,282,553 km2(July 1, 2018)

So, JAXA rises from the dead. here we go again.

Extent loss for the melting season to date is, at 4.61 million km2, 580 k below the average for the last 10 years. That is a significant amount, about one weeks average melt for the time of year. See the graph on how consistently slower than or average daily melt has been for some time.

Extent is now 233k (2.5%) above the average for 2010-2017.

On average 52% of the melting is done for this season - not such a long way to go, on average 73 days.

Excluding 2012 from the 10 year average remaining extent loss. The outcome for the minimum then comes in at 4.61 million km2 as opposed to 4.51 million km2. The range of outcomes from the last 10 years remaining melt is 3.52 to 5.23 million km2, (The average September minimum of the last 10 years was 4.41 million km2).

Rather than seeing the June Cliff, in June we continued to see a slowing of extent loss to more and more below the average.

ps: JAXA extent data not showing the strong area loss shown in NSIDC area data in the last 4 days of June
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Ned W

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Re: 2018 sea ice area and extent data
« Reply #935 on: July 02, 2018, 01:19:13 PM »
OK, here's an updated version of the table showing attempts to "predict" the missing JAXA values based on either NSIDC or Uni Bremen. 

Turns out that they were both biased slightly too high.  Ignoring the other extent metrics and just taking the average decline (2007-2017) for each day would have been slightly too low, but better.

DateJaxa(actual!)Jaxa(Avg)Jaxa(NSIDC)Jaxa(Bremen)
22 June9.909.929.959.94
23 June9.849.859.879.87
24 June9.779.769.849.82
25 June9.709.699.809.81
26 June9.639.619.829.73
27 June9.569.53n/a9.64

This is somewhat galling.  Incorporating knowledge of extent from NSIDC and Bremen made the predictions worse?  I guess the "problem" is just that 2018 was too close to the average during this six-day period to leave room for much improvement.


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

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #936 on: July 02, 2018, 01:29:17 PM »
.......attempts to "predict" the missing JAXA values based on either NSIDC or Uni Bremen. 

Turns out that they were both biased slightly too high.  Ignoring the other extent metrics and just taking the average decline (2007-2017) for each day would have been slightly too low, but better.

This is somewhat galling.  Incorporating knowledge of extent from NSIDC and Bremen made the predictions worse?  I guess the "problem" is just that 2018 was too close to the average during this six-day period to leave room for much improvement.

Different instruments, different algorithms ? Hidden inbuilt biases ? NSIDC pixel size 625 km2, AMSR2 pixel size 100 km2 ?

If JAXA produced area data a la NSIDC, I would use that to make consistency with the JAXA extent data.
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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #937 on: July 02, 2018, 01:47:35 PM »
[ADS-NIPR-JAXA] ASI Extent.

July 1st, 2018: 9,282,553 km2, a drop of -78,898 km2.
2018 is the 8th. lowest on record.

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.

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #938 on: July 02, 2018, 02:01:35 PM »
NSIDC Total Area as at 1 July (5 day trailing average) =    7,425,509   km2
This is down to 249 k above the 2010-2017 average


Total Area loss 121K    
Central Seas 101 k Periphery 9k, Other Seas 11k
 

Analysis of individual seas.

Pacific Side
- The Okhotsk Sea area is 14 k (down 4k),
- The Bering Sea area is 6k 9down 1k),
- Chukchi Sea loss 8 k,
- Beaufort Sea loss 25  k,
i.e. Pacific side loss accelerating.

Atlantic Side
- Total area loss of the Baffin, Greenland, and Barents Seas 9 k,
of which the Baffin Sea loss was 4 k, the Greenland Sea gain 0k,and  the Barents loss 4k
- The Kara Sea area loss 15 k.
- The Laptev Sea area loss 20 k  .

CAB
- The Central Arctic Sea loss 30 k
- The Canadian Archipelago gain 4 k
- East Siberian Sea loss 7 k

Other seas
- St Lawrence area at 2 k down 1 k,
- Hudson Bay area loss 6 k,.

Central Arctic Sea area loss remains impressive
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oren

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Re: 2018 sea ice area and extent data
« Reply #939 on: July 02, 2018, 03:49:27 PM »
Not a single JAXA century break throughout the whole month, if I am not mistaken. Impressive.

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Re: 2018 sea ice area and extent data
« Reply #940 on: July 02, 2018, 04:19:19 PM »
That's right, although there were also no June century breaks in 2003, 2004, 2008, and 2016. 

The biggest single-day loss of ice in June 2018 was 92.389k (21 to 22 June).  That nearly broke the record for the lowest maximum daily loss in June (2004's maximum loss was 92.334, just a hair lower).

2018 did set a record for the largest 1-day *gain* of ice in June (4.408k, from 17-18 June).

The average daily loss in June 2018 was 50.9965k.  That was fourth lowest, after 2004, 2015, and 2016.

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Re: 2018 sea ice area and extent data
« Reply #941 on: July 02, 2018, 07:50:54 PM »
Century increase in NSIDC tomorrow? (as the faulty data of 27th drops out of the 5 day average)

Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #942 on: July 03, 2018, 05:54:52 AM »
[ADS-NIPR-JAXA] ASI Extent.

July 2nd, 2018: 9,188,596 km2, a drop of 93,957 km2.
2018 is the seventh lowest on record.
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.

Lord M Vader

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Re: 2018 sea ice area and extent data
« Reply #943 on: July 03, 2018, 01:46:55 PM »
Another century break from NSIDC. Now down to 9,631 Mn km2. The trailing 5 day-average is now 9,868 Mn km2. Still about 500K above 2012 and 700K above 2010 which was lowest for the date. Still 8th lowest but by tomorrow we'll likely be 9th lowest as 2007 should take over our 8th place. And remark, we can't rule out that 2013 will put us down to 10th lowest place(!)

Arctic is surely a strange place!!

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #944 on: July 03, 2018, 07:11:01 PM »
Quote
Richard Rathbone

Century increase in NSIDC tomorrow? (as the faulty data of 27th drops out of the 5 day average)


Increase - yes, but not a century, just 18k, and especially marked in the CAA and Central Arctic Sea. See below for a fairly odd variation between seas.

NSIDC Total Area as at 2 July (5 day trailing average = 7,443,232 km2
This is up to 372 k above the 2010-2017 average


Total Area GAIN 18K    
Central Seas GAIN 29 k Periphery GAIN 8k, Other Seas LOSS 19k
 

Analysis of individual seas.

Pacific Side
- The Okhotsk Sea area is 11 k (down 3k),
- The Bering Sea area is 3k (down 3k),
- Chukchi Sea loss 10 k,
- Beaufort Sea loss 9 k,
i.e. Pacific side loss did continue.

Atlantic Side
- Total area GAIN of the Baffin, Greenland, and Barents Seas 11 k,
of which the Baffin Sea Gain was 10 k, the Greenland Sea gain 0k,and  the Barents GAIN 1 k
- The Kara Sea area loss 10 k.
- The Laptev Sea area loss 23 k  .

CAB
- The Central Arctic Sea GAIN 51 k
- The Canadian Archipelago gain 33 k
- East Siberian Sea loss 3 k

Other seas
- St Lawrence area at 2 k down 1 k,
- Hudson Bay area loss 16 k.

Central Arctic Sea area still at 2010's average despite large gain (correction?)
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Juan C. García

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Re: 2018 sea ice area and extent data
« Reply #945 on: July 04, 2018, 06:07:55 AM »
[ADS-NIPR-JAXA] ASI Extent.

July 3rd, 2018: 9,135,523 km2, a drop of -53,073 km2.
2018 is the ninth lowest on record.
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.

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #946 on: July 04, 2018, 11:19:11 AM »
JAXA Arctic Sea Ice Extent 9,135,523 km2(July 3, 2018)

There is nothing really to add to Juan's post except the attached tables and graph, but I will add:-
- extent loss is slow, really slow,
- average resulting minimum now above 4.5 million km2,
- 54% of melting done (average).


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Re: 2018 sea ice area and extent data
« Reply #947 on: July 04, 2018, 03:07:47 PM »
A small drop in NSIC extent, a big drop in area, and so a big drop in compactness. 2018 still in the middle of the pack:
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Re: 2018 sea ice area and extent data
« Reply #948 on: July 04, 2018, 03:14:35 PM »
2018 JAXA ASI extent continues its underperforming ways. The June 3rd decrease of 53k marked the 11th consecutive day with a drop less than the 10-year (2008-2017) average for the day. In fact, only two of the last 27 days have seen a decrease larger than that average. The total 27-day change over that 10-year period has averaged 1.96M km2; this year a drop of only 1.38M. (The leader for the period was 2012, which fell by a fairly massive 2.43M over the same stretch.)

In another four weeks, the parabola starts flaring out toward the minimum, so if 2018 is to stay in, say, the bottom ten, it'll need to go on a tear. Most likely guess as of now: a tepid minimum of around 5M.

gerontocrat

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Re: 2018 sea ice area and extent data
« Reply #949 on: July 04, 2018, 03:32:44 PM »
Normal service has been resumed (I assume)

NSIDC Total Area as at 3 July (5 day trailing average =  7,322,463 km2
This is 359 k above the 2010-2017 average


Total Area loss 121K    
Central Seas loss 84 k Periphery loss 11k, Other Seas loss 26k
 

Analysis of individual seas.

Pacific Side
- The Okhotsk Sea area is 8 k (down 3k),
- The Bering Sea area is 3k ,
- Chukchi Sea loss 13 k,
- Beaufort Sea loss 11 k,

Atlantic Side
- Total area loss of the Baffin, Greenland, and Barents Seas 11 k,
of which the Baffin Sea loss was 8 k, the Greenland Sea gain 0k,and  the Barents Sea loss 3 k
- The Kara Sea area loss 13 k.
- The Laptev Sea area loss 24 k  .

CAB
- The Central Arctic Sea loss 6 k
- The Canadian Archipelago gain 1 k
- East Siberian Sea loss 18 k

Other seas
- St Lawrence area at 2 k,
- Hudson Bay area loss 24 k.

ps: Laptev Sea Area has been 18 days lowest in satellite record since 11 June.
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