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ORH_wxman

Arctic Sea Ice Extent, Area, and Volume

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Late season dirty ridging is so dangerous because it is carrying the momentum from peak insolation. At least that's how I interpret the situation.

Here is some perspective.

index.php?action=dlattach;topic=2533.0;a

ice_conc_last_n_en.png

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Looks like everyone's referring to different data ...

The curve I'm looking at ... 2019 has more ice loss than 2012 to date.... not saying the season ends up that way - or even if that date relative measure is correct ... but

sea_ice_only.jpg

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On 7/1/2019 at 8:49 AM, Weatherdude88 said:

Despite all of the hyperbole and wish casting, 2019 will not be in the top 3 lowest sea ice minimums on record in area or extent. We may not end up in the top 5 in a sea ice area metric (looking at UH AMSR2 and NSIDC daily data and extrapolating).

The regions that will matter at the end of the 2019 melt season are the Central Arctic Basin, East Siberian sea, Beautfort sea, Greenland sea, and Canadian Archipelago.

For the most part, we are lagging the highest melt years in these regions (There are 5 years that lead 2019 in all these areas combined). 

There is too much high latitude ice in the critical regions. All the subjective interpretation of data will not translate to reality, no matter how many members reiterate it.

By the end of the first week of August, it will become evident that 2019 will be ordinary, as it relates to sea ice minimums over the last decade.

wdxQqA2.png

zpiOWzX.png

VzLU4wP.png

36FecQf.png

 

haha

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NSIDC daily extent holding steady on the 14th allowed 2019 to fall behind 2012 by 246k. But the area was able to move closer to 2012 than it has been over the last week.

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/Sea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx

.............2012......2019

8-13.....4.889......4.966.....77k behind

8-14.....4.724......4.970.....246k behind

 8-15.....4.679

 8-16.....4.619

8-17.....4.545

8-18.....4.520

8-19.....4.405

 8-20.....4.313

NSIDC area

https://cryospherecomputing.tk/

16E2FFDD-C0DE-4689-BD66-D6F999340757.png.0d929ea5a24fa9e2c3378fdf70ce98f7.png

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5 hours ago, bluewave said:

NSIDC daily extent holding steady on the 14th allowed 2019 to fall behind 2012 by 246k. But the area was able to move closer to 2012 than it has been over the last week.

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/seaice_analysis/Sea_Ice_Index_Daily_Extent_G02135_v3.0.xlsx

.............2012......2019

8-13.....4.889......4.966.....77k behind

8-14.....4.724......4.970.....246k behind

 8-15.....4.679

 8-16.....4.619

8-17.....4.545

8-18.....4.520

8-19.....4.405

 8-20.....4.313

NSIDC area

https://cryospherecomputing.tk/

16E2FFDD-C0DE-4689-BD66-D6F999340757.png.0d929ea5a24fa9e2c3378fdf70ce98f7.png

Yeah that IMS chart post just updated as of the 11th and looks nothing like that - interesting

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Loss rate has slowed enough last few days for NSIDC extent to fall behind 2012 by 242k as of 8-15.

.............2012......2019

 8-13.....4.889......4.966.....77k behind

8-14.....4.724......4.970.....246k behind

 8-15....4.679......4.921.....242k behind

 8-16....4.619

8-17.....4.545

8-18.....4.520

8-19.....4.405

 8-20.....4.313

NSIDC updated their projection for the September minimum. They are now calling for a 2nd place finish behind 2012.

https://nsidc.org/arcticseaicenews/2019/08/dead-heat/

The ASINA team conducted a revised analysis of the likely course of the 2019 Arctic summer sea ice minimum, using rates of loss from several recent years. While sea ice extent is now above extent for the same date in 2012, overall our projection for the minimum is lower than estimated in our previous post. Using the average decline rate of the past 12 years, from 2007 to 2018, the 2019 minimum is estimated to be 3.75 million square kilometers (1.45 million square miles). If the 2012 decline pattern is applied from August 14 forward, sea ice reaches 3.44 million square kilometers (1.33 million square miles). This is still above the 2012 summer minimum extent of 3.39 million square kilometers (1.31 million square miles). However, nearly all of the recent rates of sea ice loss lead to 2019 being second lowest in ice extent, surpassing 2007 and 2016.

 

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25 minutes ago, bluewave said:

Loss rate has slowed enough last few days for NSIDC extent to fall behind 2012 by 242k as of 8-15.

.............2012......2019

 8-13.....4.889......4.966.....77k behind

8-14.....4.724......4.970.....246k behind

 8-15....4.679......4.921.....242k behind

 8-16....4.619

8-17.....4.545

8-18.....4.520

8-19.....4.405

 8-20.....4.313

NSIDC updated their projection for the September minimum. They are now calling for a 2nd place finish behind 2012.

https://nsidc.org/arcticseaicenews/2019/08/dead-heat/

The ASINA team conducted a revised analysis of the likely course of the 2019 Arctic summer sea ice minimum, using rates of loss from several recent years. While sea ice extent is now above extent for the same date in 2012, overall our projection for the minimum is lower than estimated in our previous post. Using the average decline rate of the past 12 years, from 2007 to 2018, the 2019 minimum is estimated to be 3.75 million square kilometers (1.45 million square miles). If the 2012 decline pattern is applied from August 14 forward, sea ice reaches 3.44 million square kilometers (1.33 million square miles). This is still above the 2012 summer minimum extent of 3.39 million square kilometers (1.31 million square miles). However, nearly all of the recent rates of sea ice loss lead to 2019 being second lowest in ice extent, surpassing 2007 and 2016.

 

Back in late July, both the average statistical decline (2010-18 period) and sensitivity analysis indicated that it was likely that Arctic sea ice extent would fall below 4.000 million square kilometers at its minimum for only the second time on record. Since then, things have remained on track for such an outcome.

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43 minutes ago, AfewUniversesBelowNormal said:

How is arctic ice doing today? 

Area and extent loss have slowed to a crawl the last couple days. We're now behind 2012 by about 300k on extent and 200k on area. 

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35 minutes ago, ORH_wxman said:

Area and extent loss have slowed to a crawl the last couple days. We're now behind 2012 by about 300k on extent and 200k on area. 

We keep saying this ...than it's not - where are y'all getting your data... I've been utilizing NOAA's IMS ...and admittedly, it has not updated since the 11th ...but there curve was substantially more loss than 2012 as of the 11th ... it'll be interesting to see if that tend trajectory could have down such a drastic 45 deg angular change so abruptly and gone back across the 2012 slope - which is what would need to have taken place according to their products in order for the current 2019 to be less disastrous -

Anyway, may be a moot point - the AO is trying to rise in the GEFs ensemble. I don't get to see the Euro EOFs but... should it rise, that may alleviate the ice loss rates - slow it down ...and in fact, if that's true they may be one in the same already... 

I want to stress though, that there's nothing gained in the longer run by 2019 failing to surpass 2012 - it means nothing.... The longer termed issue with the polar ice cap remains dire... I'm hoping there isn't some coveted like idea that we are coming out of the arctic crisis?   ... just sayn'

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On August 17, Arctic sea ice extent was 4.635 million square kilometers (JAXA). Arctic sea ice extent remains on track of the second lowest figure on record.

If Arctic sea ice extent declines at the 2010-18 mean rate, it would achieve a minimum figure of 3.695 million square kilometers. The median rate would produce a minimum extent of 3.672 square kilometers.

Implied probabilities based on sensitivity analysis:

4.000 million square kilometers or below: 84%
3.750 million square kilometers or below: 57%
3.500 million square kilometers or below: 26%

Highest 25th percentile: 3.905 million square kilometers
Lowest 25th percentile: 3.486 million square kilometers

In sum, Arctic sea ice extent will very likely fall below 4.0 million square kilometers for only the second time on record.

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2 hours ago, Typhoon Tip said:

We keep saying this ...than it's not - where are y'all getting your data... I've been utilizing NOAA's IMS ...and admittedly, it has not updated since the 11th ...but there curve was substantially more loss than 2012 as of the 11th ... it'll be interesting to see if that tend trajectory could have down such a drastic 45 deg angular change so abruptly and gone back across the 2012 slope - which is what would need to have taken place according to their products in order for the current 2019 to be less disastrous -

Anyway, may be a moot point - the AO is trying to rise in the GEFs ensemble. I don't get to see the Euro EOFs but... should it rise, that may alleviate the ice loss rates - slow it down ...and in fact, if that's true they may be one in the same already... 

I want to stress though, that there's nothing gained in the longer run by 2019 failing to surpass 2012 - it means nothing.... The longer termed issue with the polar ice cap remains dire... I'm hoping there isn't some coveted like idea that we are coming out of the arctic crisis?   ... just sayn'

Here's some sources....the record we discuss isn't supposed to be about what it means longer term. Most of us know the longer term trend is down. But records are interesting to all of us in the weather community. Why do we sit around and track the thermometer at 101F on a hot summer day when the record is 102F? Does it really feel much different from 99F? Of course not, we're just tracking whether the record gets broken or not. FWIW, we've discussed when we think the first total melt out (definition below 1 million sq km of extent) will be in here:

https://www.americanwx.com/bb/topic/40881-when-we-will-see-an-ice-free-arctic/

https://www.americanwx.com/bb/topic/46677-when-will-the-2012-arctic-ice-extent-minimum-record-be-broken/?page=3

 

It does not appear we will set a new record this year based on JAXA, ubremen, and NSIDC. We'll see about the IMS plot you reference but is suspect that will flatten out at some point. 

https://docs.google.com/viewer?a=v&pid=sites&srcid=ZGVmYXVsdGRvbWFpbnxhcmN0aXNjaGVwaW5ndWlufGd4OjU1OGIwZWI0NGI2ZDI5YTM

https://seaice.uni-bremen.de/sea-ice-concentration/

https://ads.nipr.ac.jp/vishop.ver1/vishop-extent.html

 

 

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 I don't know… It strikes me a bit like people just not wanting a record to be broken I'm sorry it does.

Otherwise the IMS plots I supplied would've been part of the discussion all along and looks a bias  when potentially valid data is elided. 

 Maybe it's not that way OK… 

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15 minutes ago, Typhoon Tip said:

 I don't know… It strikes me a bit like people just not wanting a record to be broken I'm sorry it does.

Otherwise the IMS plots I supplied would've been part of the discussion all along and looks a bias  when potentially valid data is elided. 

 Maybe it's not that way OK… 

Well, it sounds like a subjective analysis then by you on other people's posting behavior. Not sure I can really help other than the below explanation:

If you go back through the beginning of this thread and previous Arctic sea ice threads, you'll note that IMS hasn't been used. It's been consistently NSIDC and JAXA...sometimes U bremen and previously Cryosphere Today (now defunct..but they used NSIDC data). 

I don't know a ton about IMS but my little experience with it from sheer recollection back to the 2009-2013 days is that it seems to lag the other datasets significantly. It will "catch up" to them eventually if it looks like it is deviating on a trend line. That is my guess on what happens this year as well. We won't have to wait long to find out. 

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12 hours ago, ORH_wxman said:

Well, it sounds like a subjective analysis then by you on other people's posting behavior. Not sure I can really help other than the below explanation:

If you go back through the beginning of this thread and previous Arctic sea ice threads, you'll note that IMS hasn't been used. It's been consistently NSIDC and JAXA...sometimes U bremen and previously Cryosphere Today (now defunct..but they used NSIDC data). 

I don't know a ton about IMS but my little experience with it from sheer recollection back to the 2009-2013 days is that it seems to lag the other datasets significantly. It will "catch up" to them eventually if it looks like it is deviating on a trend line. That is my guess on what happens this year as well. We won't have to wait long to find out. 

ISM is lagging by date ... as of last check... They seem to update that about every 10 days...and it's for the previous week, too...so by the time it's published it's an addition three or so days beyond that week... Aug 11 ... That's what I've seen from them since July.  They'll probably release an analysis for the 18th in about two days...  oy - 

As far as the subject crap - nah dude.  More like concern... I don't really care if people want/need/do/or don't have biases... I just want to know that what I'm reading isn't that - which admittedly is probably not going to happen in a public social media source.  :) word.   Just so we're clear. In order to make that assessment... I may sound I like I care about specific posting behavior ... but that's not it.  

I'm not sure anything you have said should invalidate IMS inclusion - not that you mean to...  I think it is at least worth it to vet why their plots vary... interesting. I'm wondering if it's density related. 

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20 hours ago, Typhoon Tip said:

We keep saying this ...than it's not - where are y'all getting your data... I've been utilizing NOAA's IMS ...and admittedly, it has not updated since the 11th ...

The IMS graph is 4k MASIE data + - a small adjustment. This data is updated daily. The value should always be within a couple k of the MASIE value. MASIE data is an adjusted value, in an easier to use format, than the initial IMS data set. 

 

ftp://sidads.colorado.edu/DATASETS/NOAA/G02186/

 

Quote

MASIE relies on data from the Interactive Multisensor Snow and Ice Mapping System (IMS)

Quote

The IMS product uses several satellite data sources including passive microwave, but it is also based on visual analysis and other data sources and undergoes a form of manual data fusion.

Quote

However, it relies more on visible imagery than on passive microwave data, so the ice edge position will generally be more accurate

 

https://nsidc.org/data/masie/masie_faq

 

17 hours ago, Typhoon Tip said:

 I don't know… It strikes me a bit like people just not wanting a record to be broken I'm sorry it does.

Otherwise the IMS plots I supplied would've been part of the discussion all along and looks a bias  when potentially valid data is elided. 

 

MASIE is an ice edge product that has continuously been upgraded / modified over the years. This is different form the area and extent products.  These are completely different and should not be compared. This product was intended to measure the ice edge based on visible imagery. The human influence and changes in data sources, make it unreliable when comparing to other years.

 

 

Quote

 

Reason for Developing MASIE

The Sea Ice Index ice extent is widely used, but the edge position can be off by 10s or in some cases 100s of kilometers. NIC produces a better ice edge product

 

 

 

https://nsidc.org/data/masie/about_masie

 

https://www.natice.noaa.gov/ims/files/ims-hydro-proc-ramsay-1998.pdf

https://www.natice.noaa.gov/ims/files/Helfrichetal_HP07.pdf

https://www.natice.noaa.gov/ims/files/ramsayESC57.pdf

 

If you want to compare apples to apples, as it relates to previous melting seasons, do not use IMS / MASIE. If you want an accurate view of current sea ice edge conditions, use IMS / MASIE. 

 

 

 

 

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48 minutes ago, Typhoon Tip said:

Fwiw - 

as of two days ago ( 18th ) from IMS: https://www.natice.noaa.gov/ims/

image.thumb.png.196646b9d18b359b0117fcc3ce39f0d7.png

It will be interesting to see if this product stays below 2012....I suspect it will not, but we'll find out in about 2-3 weeks.

 

NSIDC area is now favored to finish 3rd lowest...we're only 90k lower than 2016 now and 2016 loses about 400k in the next week. So this year needs to kick-start again on area loss to stay pace. Extent is still favored to finish 2nd lowest behind 2012 on NSIDC, Ubremen, and Jaxa.

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15 minutes ago, ORH_wxman said:

It will be interesting to see if this product stays below 2012....I suspect it will not, but we'll find out in about 2-3 weeks.

 

NSIDC area is now favored to finish 3rd lowest...we're only 90k lower than 2016 now and 2016 loses about 400k in the next week. So this year needs to kick-start again on area loss to stay pace. Extent is still favored to finish 2nd lowest behind 2012 on NSIDC, Ubremen, and Jaxa.

I have a question - which may be fairly 'duh' but since I haven't been by those other sources ... Are those more comprehensive than "sea ice only" ? 

That IMS product is sea ice only ... And also, just fyi ... the IMS product comes from NSIDC - we may be able to put the pieces together here on why the disparity.  It's gotta just be some dumb product thing I'm not seeing shit

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Okay ... .this is just quick and dirty Web goop but... 

IMS is being used by the National Snow and Ice Date Center ... 

 

IMS Daily Northern Hemisphere Snow and Ice Analysis at 1 km, 4 km, and 24 km Resolutions, Version 1. This data set provides maps of snow cover and sea ice for the Northern Hemisphere from February 1997 to the present from the National Ice Center's Interactive Multisensor Snow and Ice Mapping System (IMS).

That's what's confusing ... if we say "...2nd lower behind NSIDC" ( which I'm not trying to refute...) but this statement above says they are using the same IMS tech, and said tech is showing 2019 has been lower than 2012 the whole way... that's a discrepancy.  

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36 minutes ago, Typhoon Tip said:

Okay ... .this is just quick and dirty Web goop but... 

IMS is being used by the National Snow and Ice Date Center ... 

 

IMS Daily Northern Hemisphere Snow and Ice Analysis at 1 km, 4 km, and 24 km Resolutions, Version 1. This data set provides maps of snow cover and sea ice for the Northern Hemisphere from February 1997 to the present from the National Ice Center's Interactive Multisensor Snow and Ice Mapping System (IMS).

That's what's confusing ... if we say "...2nd lower behind NSIDC" ( which I'm not trying to refute...) but this statement above says they are using the same IMS tech, and said tech is showing 2019 has been lower than 2012 the whole way... that's a discrepancy.  

The NSIDC data I'm using is from their satellite dataset. Specifcally the SSMI/S satellite. Jaxa and U Bremen use the AMSR2 satellite, which is highest resolution of the two. SSMI/S is useful though because it has a pretty homogeneous dataset going back to 1979.

 

IMS uses both satellite and human augmentation of the data based on visual shots of the ice.

 

Here's the FAQ from MASIE/IMS site:

https://nsidc.org/data/masie/masie_faq

 

 

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2 hours ago, ORH_wxman said:

The NSIDC data I'm using is from their satellite dataset. Specifcally the SSMI/S satellite. Jaxa and U Bremen use the AMSR2 satellite, which is highest resolution of the two. SSMI/S is useful though because it has a pretty homogeneous dataset going back to 1979.

 

IMS uses both satellite and human augmentation of the data based on visual shots of the ice.

 

Here's the FAQ from MASIE/IMS site:

https://nsidc.org/data/masie/masie_faq

 

 

Yeah that product I posted is the MASIE ... or the augmented IMS ...  hints at that in the lower right text block ...which for some reason had previous escaped my attention.  Heh... anyway I found a different site that describes similarly when searching this shit -

anyway, I think these curves have to converge at some point - thing is... we're so close to shared curve space that's probably splitting hairs at the moment...  2012 vs 2019 I mean

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On August 20, Arctic sea ice extent was 4,507,767 square kilometers on JAXA. Only 2007 (4,877,731 square kilometers), 2012 (4,143,648 square kilometers) and 2016 (4,922,931 square kilometers) had figures below 5 million square kilometers by August 20.

Based on sensitivity analysis, the following are implied probabilities for various minimum extent figures:

4.50 million square kilometers or below: 99.9%
4.25 million square kilometers or below: 98%
4.00 million square kilometers or below: 86%
3.75 million square kilometers or below: 55%
3.50 million square kilometers or below: 20%

75th percentile: 3.895 million square kilometers
25th percentile: 3.543 million square kilometers

Minimum extent figures based on historic 2010-2018 data:

Mean decline: 3.719 million square kilometers
Median decline: 3.711 million square kilometers
Minimum decline: 3.922 million square kilometers
Maximum decline: 3.542 million square kilometers

Summary:

Through August 21, Arctic sea ice extent remains firmly on a path that will very likely result in the second lowest minimum extent figure on record and the second such figure below 4.0 million square kilometers.

 

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2019 is at the 10th lowest NSIDC extent as of 8-20.

3.387....2012-9-17

4.155....2007-9-18

4.165....2016-9-10

4.344....2011-9-11

4.433....2015-9-9

4.586....2018-9-23

4.615....2010-9-21

4.656....2018-9-23

4.665....2017-9-13

4.734....2019

3A90B22B-49F8-4AC3-9EA6-953A8BEEA8C6.thumb.png.304e91935790135371385a16a1160b39.png

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21 minutes ago, bluewave said:

2019 is at the 10th lowest NSIDC extent as of 8-20.

3.387....2012-9-17

4.155....2007-9-18

4.165....2016-9-10

4.344....2011-9-11

4.433....2015-9-9

4.586....2018-9-23

4.615....2010-9-21

4.656....2018-9-23

4.665....2017-9-13

4.734....2019

yeah...it's interesting to see 2019 be within decimals of those floor values when there's an average bottom date of Sept -16 among those other years, and we're only on August 21  :yikes:

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2012 was essentially an anomalous year due to the great Arctic cyclone.

This year maintained the status quo but it'll be more interesting to see what happens next year.

The last few years had horrible ice recoveries vs the early 2010s and this year should be no different. A very poor recovery could lead to a new record next year. 

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4 minutes ago, SnoSki14 said:

2012 was essentially an anomalous year due to the great Arctic cyclone.

This year maintained the status quo but it'll be more interesting to see what happens next year.

The last few years had horrible ice recoveries vs the early 2010s and this year should be no different. A very poor recovery could lead to a new record next year. 

The role of the cyclone in 2012 is overstated imho. The ice was in terrible shape before it hit. I'm not really convinced it added that much to the losses. Maybe a couple hundred thousand sqkm or something. 

2012 already had the highest percentage of melt ponds by the end of June suggesting a new record was likely. It was significantly lower on SSMI/S area than other years including 2019...it's the main reason I didn't think we'd set a new record this year despite this being the most favorable melt year in a while. It just didn't quite stack up to 2012's early melt ponding. 

 

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I think the badly stressed/fractured ice means we can no longer get the scale 'meltponding' we saw back in 2012?

There are too many 'drain points' in the ice these days

This does not mean 'other factors' have now taken up that slack and so preconditioned the ice for melt?

The reduction in flow size by 'bottom melt' end of the season now means 'side melt' takes ever more of the floe compared with the old multi km floes where ,compared with the 'bottom melt', such losses were negligible?

The ice itself is making itself ever easier to melt more ice for the same amount of energy!

 

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