Arctic Sea Ice Extent, Area, and Volume

[Typhoon Tip]

Fwiw - 

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

[ORH_wxman]

48 minutes ago, Typhoon Tip said:

Fwiw - 

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

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.

[Typhoon Tip]

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

[Typhoon Tip]

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.  

[ORH_wxman]

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

 

 

[Typhoon Tip]

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

[donsutherland1]

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.

 

[bluewave]

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

[Typhoon Tip]

This is gonna be close ...  

[Typhoon Tip]

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  

[SnoSki14]

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. 

[ORH_wxman]

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. 

 

[Gray-Wolf]

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!

 

[Bhs1975]

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!

 

 

Yeah the feedbacks kicking in should mean an ice free arctic year round in about a decade.

 

 

.

[ORH_wxman]

50 minutes ago, Gray-Wolf said:

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!

 

Melt ponding is supposed to occur more readily on first year ice than multiyear according to the literature but let's say that is flawed analysis....if melt ponding was truly getting harder because first year ice is somehow getting so bad and other factors now contribute more to melting because of this, then we would expect the NSIDC area in late June to significantly over-predict the amount of ice left at the end of the season. We haven't really seen that in recent years....except 2016. But it didn't happen in 2017 or 2018. 

It doesn't look to happen in 2019 either unless something pretty crazy happens in the next couple weeks.

The late June area data (which is a proxy for melt ponds) told us that we had a good chance for 2nd lowest but not a good chance for lower than 2012's record.  There's nothing glaring that says that data missed some sort of smoking gun on additional melting. 

[Typhoon Tip]

I'm curious if the ensemble push for an elevating NAM might help in preventing a nadir quite as deep as 2012 ...  We're still likely doing a bottom 3 ranking ( or so...) either way, but if the oscillation/mode relaxes toward neutral we could be on the verge of a slowing in the melt rates.    + annular modes are actually inversely temperature distributive to middle latitudes and tends to favor land-based cryo ... in addition to cooling the polar vortex domain space. But not sure about sea ice though. Particularly this early in the in the boreal autumn ...and also considering the melt- inertia, which is also a factor.  

[bluewave]

Larger 94k daily drop on 8-22 for NSIDC extent. This moves 2019 into 8th place at 4.628 million sq km.

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

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

4.628....2019

4.656....2018-9-23

4.665....2017-9-13

 

[donsutherland1]

On August 23, Arctic sea ice extent was 4,412,266 square kilometers on JAXA.

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

4.25 million square kilometers or below: 99%
4.00 million square kilometers or below: 86%
3.75 million square kilometers or below: 45%
3.50 million square kilometers or below: 9%

75th percentile: 3.918 million square kilometers
25th percentile: 3.635 million square kilometers

Minimum extent figures based on historic 2010-2018 data:

Mean decline: 3.776 million square kilometers
Median decline: 3.788 million square kilometers
Minimum decline: 3.941 million square kilometers
Maximum decline: 3.618 million square kilometers

Summary:

Through August 23, 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.

[AfewUniversesBelowNormal]

weird.. it's going to roll into -AO next Summer. 

[bluewave]

35 minutes ago, Weatherdude88 said:

 

Extent and area where already stalling before the storm. Many thought the storm would accelerate losses. The stall is due to the positioning of the remaining sea ice as it relates to longitude and latitude. In previous high melt years, there was significantly more sea ice at lower latitudes in easier to melt spots. This was not the case this year. This is also evident in Slater Probabilistic Sea Ice Extent forecast. The slow down was inevitable.

The extent loss rate began to stall a few days before the storm around the 20th. The record breaking high pressure regime that had been in place since May reversed. So the ice pack became  less compact and spread out with colder temperatures.

 

[ORH_wxman]

Area is very likely to finish in 3rd place given the path of 2016 from here on out. 

Extent is still looking like 2nd place is the most likely but the recent stall has made 3rd or 4th place more possible than it was a week ago. 

[Typhoon Tip]

10 minutes ago, ORH_wxman said:

Area is very likely to finish in 3rd place given the path of 2016 from here on out. 

Extent is still looking like 2nd place is the most likely but the recent stall has made 3rd or 4th place more possible than it was a week ago. 

That's what I've been hitting at yup.   We'll see.

The AO mode is shifting more positive in the means.   Not sure what the general level of knowledge is re that particular atmospheric index but, when it is positive, we tend to warm at mid latitudes around the 45th parallel of the Hemi, while the polar vortex strengthens.   That is concomitant with height falls and cold genesis within the mean PV - so essentially diametrical to our correlations.   +AO cold up there, warm down here; -AO vice versa...

What I am getting at is that maybe we see a slowing coming into the end here and that bumps 2019 out of contention for top apocalypse indicator, to something more like we be dire-f'ed

[Typhoon Tip]

1 hour ago, Weatherdude88 said:

 

Extent and area where already stalling before the storm. Many thought the storm would accelerate losses. The stall is due to the positioning of the remaining sea ice as it relates to longitude and latitude. In previous high melt years, there was significantly more sea ice at lower latitudes in easier to melt spots. This was not the case this year. This is also evident in Slater Probabilistic Sea Ice Extent forecast. The slow down was inevitable.

It is long been scienced and introduced via attribution studies/papers, just how sensitive the Arctic is.   

The question of ice morphology would certainly play into that mystique, especially when the domain is "teetering" with thermal resonance that is near melt point(s) - and there may be some variation there, too, based upon saline content.   Up a degree, ice melts;  down a degree; it-honeycombs/softens, but may remain in tact. 

I was just mentioning to Will that the NAM is rising.  Those areas recently released could refreeze, but either way, the ablation rates would slow in a system that is on the thermal fence so to speak, pretty markedly over a rather narrow range of temperature input.  

[ORH_wxman]

3 minutes ago, Weatherdude88 said:

 

If you take an average of the melt rate for the past 8 years, 2019 would end up with a final value of 4.148 millions of square kilometers of sea ice extent for the minimum value. 2019 would finish with the third lowest daily minimum value, just ahead of 4.145 millions of square kilometers lowest single daily value for 2016. If you remove 2 of the higher sea ice extent melt years (2015 and 2016), the final value using average melt in 6 of the last 8 years has even more distance from the 2016 minimum value.

Are you on the record predicting a sea ice extent melt rate greater than the last 8 year average from now until minimum? 

 

 

I was looking at JAXA when I made the comments about extent. I agree NSIDC extent looks a bit less likely to finish 2nd but it wouldn't surprise me either. It only needs to have slightly above average losses...though the shape of the ice pack doesn't look as favorable for losses compared to years like 2016 when there was a lot more vulnerable ice left. 

[AfewUniversesBelowNormal]

I don't know, rate of decline of arctic ice seemed much more in the late 1990s through 2007. If you run a linear line forward for the last 12 years, this season is below normal in it's decrease. 

[donsutherland1]

1 hour ago, AfewUniversesBelowNormal said:

I don't know, rate of decline of arctic ice seemed much more in the late 1990s through 2007. If you run a linear line forward for the last 12 years, this season is below normal in it's decrease. 

The JAXA data suggests otherwise.

1990-2007: Mean Melt: 8.897 million square kilometers (59.4% of mean maximum)

2008-2018: Mean Melt: 9.916 million square kilometers (69.2% of mean maximum)

[AfewUniversesBelowNormal]

Images on NASA suggested otherwise, but that's just surface based. I would think "normally" we would be accelerating more ice loss by now. 

[ORH_wxman]

57 minutes ago, Weatherdude88 said:

For 8.26, the NSIDC northern hemisphere sea ice extent value is 4.654 millions of square kilometers. This is a decrease of 25,000 square kilometers.

2019 now has 748,000 square kilometers more sea ice extent than 2012. 2019 now has 48,000 square kilometers less sea ice than 2016, 146,000 square kilometers less sea ice than 2007, and 189,000 less sea ice than 2011 for the date.

We still have our first candidate for the 2019 northern hemisphere sea ice minimum. We are now 26,000 squared kilometers above the August 22nd value.

 

There is no way the min would be that early.

[Typhoon Tip]

On 8/21/2019 at 3:29 PM, Bhs1975 said:

 

Yeah the feedbacks kicking in should mean an ice free arctic year round in about a decade.

 

 

.

Mm...  No not likely.   "Year round," as in 'never' gaining ice back at all?  That's not likely to be a reality in anyone's lifetime.   

If you/we mean that N. Hemisphere summers experience transient open sea conditions; that may occur at some point. Who knows if that would be a decade.  Timing such a reality would depend upon how "accelerated" the acceleration is, as per recent studies go. 

There will be an ice-cap-transition period where there are summers with open seas that fluctuate back to ice cover the following winters.  In fact, it's entirely possible that would happen with irregularity, too - some years the summer retains a small ice-cap, and then the next year ... the summer sees it disappear again. Only to repeat either scenario. 

That may go on for quite a while actually, long before any kind of Paleo./eocene thermal max -related sort of redux fully takes over. 

Anyway, there's going to be some growing pains. These longer term changes can and do take place in shorter orders of time, and acceleration in the present climate models, as well as empirical data do send alarming signals that "shorter" may favored over longer. But, we have to remember, shorter in the context of geology is still a bit of an existential misnomer. 

But this is not to dissuade you  It's better for the world if folks are open-minded, vigilant toward more dire plausibility, because obviously it is the dire realities that cause the extinctions - not the relative utopias.

 

 

[Orangeburgwx]

49 minutes ago, Typhoon Tip said:

Mm...  No not likely.   "Year round," as in 'never' gaining ice back at all?  That's not likely to be a reality in anyone's lifetime.   

If you/we mean that N. Hemisphere summers experience transient open sea conditions; that may occur at some point. Who knows if that would be a decade.  Timing such a reality would depend upon how "accelerated" the acceleration is, as per recent studies go. 

There will be an ice-cap-transition period where there are summers with open seas that fluctuate back to ice cover the following winters.  In fact, it's entirely possible that would happen with irregularity, too - some years the summer retains a small ice-cap, and then the next year ... the summer sees it disappear again. Only to repeat either scenario. 

That may go on for quite a while actually, long before any kind of Paleo./eocene thermal max -related sort of redux fully takes over. 

Anyway, there's going to be some growing pains. These longer term changes can and do take place in shorter orders of time, and acceleration in the present climate models, as well as empirical data do send alarming signals that "shorter" may favored over longer. But, we have to remember, shorter in the context of geology is still a bit of an existential misnomer. 

But this is not to dissuade you  It's better for the world if folks are open-minded, vigilant toward more dire plausibility, because obviously it is the dire realities that cause the extinctions - not the relative utopias.

 

 

You deserve a medal... That was brilliant