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jdallen

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Re: The 2020 melting season
« Reply #4100 on: July 29, 2020, 09:06:10 PM »
The Beaufort low is clearly visible on Worldview today. Unusually clear spiral pattern.
This, is a terrifying image.

It exemplifies just how totally broken atmospheric circulation is in the northern hemisphere.

The import of this on weather in more densely inhabited latitudes is profound.
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Gizmo

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Re: The 2020 melting season
« Reply #4101 on: July 29, 2020, 09:13:14 PM »
:o

JAXA arctic sea ice volume

Well that's terrifying.

To quote jdallen, "The import of this on weather in more densely inhabited latitudes is profound."

I'm expecting a truly bizarre winter this year here @ 47 degrees north.

ArcticMelt2

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Re: The 2020 melting season
« Reply #4102 on: July 29, 2020, 09:34:53 PM »
A clear view of the compression ridges in Hudson Bay. There is a similar ridge from the perennial ice near the northern shores of Canada and Greenland.

jdallen

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Re: The 2020 melting season
« Reply #4103 on: July 29, 2020, 09:37:44 PM »
And here is an example of why extent is not crashing.

Laptev sea margin from 8 days ago vs. today (the 29th).

A bit of fuzziness from the clouds in today's image, but it is obvious the entire pack is exploding northwards and disintegrating as it re-crosses the heated waters of the Laptev.

Area in frame is ~700,000km2

(Edit:  Area will continue to drop, and I'm of a mind that volume is currently being butchered savagely out of proportion to the other two metrics.)
« Last Edit: July 29, 2020, 09:43:04 PM by jdallen »
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ArcticMelt2

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Re: The 2020 melting season
« Reply #4104 on: July 29, 2020, 09:43:46 PM »
And here is an example of why extent is not crashing.

Laptev sea margin from 8 days ago vs. today (the 29th).

A bit of fuzziness from the clouds in today's image, but it is obvious the entire pack is exploding northwards and disintegrating as it re-crosses the heated waters of the Laptev.

Area in frame is ~700,000km2


There is not only the Laptev Sea, but also the East Siberian Sea.

http://osisaf.met.no/quicklooks/prod/ice/2020/07/ice_drift_nh_polstere-625_multi-oi_202007261200-202007281200_combo.png

ajouis

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Re: The 2020 melting season
« Reply #4105 on: July 29, 2020, 10:14:11 PM »
:o

JAXA arctic sea ice volume

isn't that near boe values for volume (1000 km*km*km)?
does anyone explain the discrepancy with piomas, is it just regular model differences or is there something I am missing?
Anyways I hope this quiets the choirs expecting a relatively muted end of season, when we're first everywhere with incredible preconditioning and almost the worst possible scenario in weather, I really don't see any evidence pointing in the other direction. Hopefully we'll still miss the mark of my prediction down below.
After a thousand steps on the ice, it cracked.
The Man looked down at the infinite blue of the sea.
On the horizon, standing still, the polar bear had just scented his next meal.

 Less than 3000 cubic kilometers this Piomas minimum.

glennbuck

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Re: The 2020 melting season
« Reply #4106 on: July 29, 2020, 10:22:19 PM »
It is falling a bit. :-X

BornFromTheVoid

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Re: The 2020 melting season
« Reply #4107 on: July 29, 2020, 10:30:48 PM »
Looks like a long lasting -ve dipole coming up. The pack will get spread out towards the Pacific and Siberian side. We will probably see extent continue fall at a slower than average rate for the next week, all while area continues to fall at a steady pace. June cliff 2.0?

5 day mean SLP with concentration overlayed below.

I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

Sambuccu

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Re: The 2020 melting season
« Reply #4108 on: July 29, 2020, 10:50:02 PM »
Well...
DMI volume is considered as somehow unreliable because it has some oddities like gaining volume at the end of august.
Here, we have huge gains in july during the GAAC. How can it be considered as reliable ?


:o

JAXA arctic sea ice volume

Well that's terrifying.

To quote jdallen, "The import of this on weather in more densely inhabited latitudes is profound."

I'm expecting a truly bizarre winter this year here @ 47 degrees north.
« Last Edit: July 29, 2020, 11:25:58 PM by Sambuccu »

glennbuck

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Re: The 2020 melting season
« Reply #4109 on: July 29, 2020, 11:21:31 PM »
Arctic sea surface temperature.

Gumbercules

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Re: The 2020 melting season
« Reply #4110 on: July 29, 2020, 11:33:23 PM »
The Beaufort low is clearly visible on Worldview today. Unusually clear spiral pattern.
So far up north the Coriolis forces are pretty small. There could be some theoretical background for the exceptionally clear spirals. Not that I would know about this. There are pretty pure spirals in tropical storms too so latitude alone cannot be a defining factor for weather to construct pure spirals. The GAC-12 was also pretty huge spiralform, on occasion if I remember correctly.

The Coriolis effect is zero at the equator. Shouldn't it get largest at the pole? At the least, it is not zero at the pole. It may be largest at the pole because at the pole there is ZERO rotation. So for a eastward wind to maintain the same momentum as it moves towards the pole it would have increase velocity to infinity. That is poorly explained, but maybe you get the point.

Tigertown

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Re: The 2020 melting season
« Reply #4111 on: July 29, 2020, 11:34:59 PM »
:o

JAXA arctic sea ice volume

isn't that near boe values for volume (1000 km*km*km)? (Snip)

Or this JAXA chart needs to be recalibrated. I think we have discussed before that it is off a little.
"....and the appointed time came for God to bring to ruin those ruining the earth." Revelation 11:18.

gandul

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Re: The 2020 melting season
« Reply #4112 on: July 29, 2020, 11:42:19 PM »
The current EC forecast seems pretty benign for the ice given the circumstances, and after this crazy July. Softening storms, negative dipole tending to disperse the ice, but not real action. Sure, there's going to be more melt than meets the eye but unless a carousel of moderate storms like the one now weakening does not ensue, or a mega dipole, or something, probably 2020 will save face and not end first.

Yes there's a lot of sun-bathed ice weak and thin but it can survive till September in a quiet and relaxing August (if that really exists in a year like this, I really doubt it).


ArcticMelt2

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Re: The 2020 melting season
« Reply #4113 on: July 29, 2020, 11:42:26 PM »
Arctic sea surface temperature.

Interesting. Nobody knows, in past years this map also showed water warmer than 0 degrees Celsius north of the 85th parallel?

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Re: The 2020 melting season
« Reply #4114 on: July 29, 2020, 11:44:08 PM »
Everyone please take a moment to go over to moyhu website and leave a message to plead for historical data to be added to his 80N dmi temperature replacement. The data is ready to go but currently the coding loads all the data at once. :(  It needs to load each year separately. 
https://moyhu.blogspot.com/p/latest-ice-and-temperature-data.html#arctic
 :)
It sounds like she/he will get to it eventually but it is not a priority.

gandul

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Re: The 2020 melting season
« Reply #4115 on: July 29, 2020, 11:48:06 PM »
Everyone please take a moment to go over to moyhu website and leave a message to plead for historical data to be added to his 80N dmi temperature replacement. The data is ready to go but currently the coding loads all the data at once. :(  It needs to load each year separately. 
https://moyhu.blogspot.com/p/latest-ice-and-temperature-data.html#arctic
 :)
It sounds like she/he will get to it eventually but it is not a priority.

Is that important?
With all its limitations DMI 80N gives me the information I want, especially in winter. We all know it is pretty useless in summer (barring anecdotal situations as the current storm dragging the heat from NA into the basin, it's basically a flat signal clamped to near melting temperature).

oren

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Re: The 2020 melting season
« Reply #4116 on: July 29, 2020, 11:51:29 PM »
Regarding JAXA volume, it is another simple and very easy to use real time tool, but providing totally unreliable information. AMSR2 cannot measure thickness properly, IIRC the tool is experimental in winter and useless in summer when surfaces are wet. It is in essence a mirror image of the (useful) surface melt extent. Posting it daily in this thread adds noise, not data.

glennbuck

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Re: The 2020 melting season
« Reply #4117 on: July 29, 2020, 11:56:56 PM »
What will be left on the 5th August!

Link below to the 5th august ice thickness.

https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticict_nowcast_anim30d.gif
« Last Edit: July 30, 2020, 12:49:37 AM by glennbuck »

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Re: The 2020 melting season
« Reply #4118 on: July 29, 2020, 11:58:48 PM »
gandul: Obviously people who don't want to will not do it. I prefer the more accurate data. If you don't why do you care if other people do things that do not effect you?

UCMiami

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Re: The 2020 melting season
« Reply #4119 on: July 30, 2020, 12:06:38 AM »
On WorldView today there is a feature visible through the thin cloud/fog that runs across the arctic from north of Greenland into the Laptev that is puzzling me. On the 7-2-1 corrected reflectance band between 150 and 120E Longitude there is an area about 86N to 84N that looks almost like dispersed ice. The northern edge seems like a clear open crack similar to others elsewhere. The only other explanation I can think of is a large area with huge melt ponding?

Attached link to WV image. Anyone have any thoughts - it does not appear to be cloud related, but the cloud layer makes it less distinct.
https://worldview.earthdata.nasa.gov/?v=-243823.10395478012,278488.3355464578,300688.89604521985,569816.3355464578&p=arctic&t=2020-07-29-T20%3A00%3A00Z&z=2&l=MODIS_Combined_Thermal_Anomalies_All(hidden),Graticule,Reference_Labels,Reference_Features,Coastlines(hidden),MODIS_Terra_CorrectedReflectance_Bands721,MODIS_Terra_CorrectedReflectance_Bands367(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor(hidden),VIIRS_SNPP_CorrectedReflectance_TrueColor

Rod

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Re: The 2020 melting season
« Reply #4120 on: July 30, 2020, 12:09:19 AM »
Whatever model you want to use to try to understand the heat currently blowing directly over the North Pole, don’t forget to look at the actual temperature data, and the current directions of the wind.

Svalbard has been on fire 🔥 and the reverse dipole is sucking all of that heat straight north over the CAB.

https://twitter.com/pat_wx/status/1288546764669280257?s=21


ArcticMelt2

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Re: The 2020 melting season
« Reply #4121 on: July 30, 2020, 12:12:18 AM »
Arctic sea surface temperature.

Interesting. Nobody knows, in past years this map also showed water warmer than 0 degrees Celsius north of the 85th parallel?

This is a snapshot of todays sea ice temperature for this years melt, i don't see anything on there that says never before seen warm water north of the 85th parallel.


No, this is a map of the temperature of the water under the ice. Ice temperature is there too.

http://ocean.dmi.dk/anim/plots/icetemp.arc.1.png

Therefore, it is interesting, in past years, was there warm water north of 85 latitude on the Danish map or not?

HapHazard

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Re: The 2020 melting season
« Reply #4122 on: July 30, 2020, 12:16:37 AM »
So, this seems intriguing to me, going forward:


ArcticMelt2

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Re: The 2020 melting season
« Reply #4123 on: July 30, 2020, 12:26:43 AM »
I could not find July but got August sea surface temperatures from the past.

Thanks for the maps. It seems that in 2007 warm water also penetrated so far to the north.

It is necessary to keep an eye on this Danish map.

glennbuck

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Re: The 2020 melting season
« Reply #4124 on: July 30, 2020, 12:37:21 AM »
So, this seems intriguing to me, going forward:

Yes i wondered if it kept going North it could split the Artic north pole apart lol, maybe i am going mad but this year is crazy.

gandul

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Re: The 2020 melting season
« Reply #4125 on: July 30, 2020, 12:48:39 AM »
gandul: Obviously people who don't want to will not do it. I prefer the more accurate data. If you don't why do you care if other people do things that do not effect you?
Just stating my two cents for the gallery. You don't like it, that's fine, I don't dig your meticulous choice.

Paul

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Re: The 2020 melting season
« Reply #4126 on: July 30, 2020, 12:54:15 AM »
So, this seems intriguing to me, going forward:

Yes i wondered if it kept going North it could split the Artic north pole apart lol, maybe i am going mad but this year is crazy.

Yep your going mad...

As others say, now the storm is weakening and forecast to move near to Greenland, the weather in theory looks favourable for the ice but again with the way this year has gone then never rule anything out.

glennbuck

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Re: The 2020 melting season
« Reply #4127 on: July 30, 2020, 12:57:03 AM »
So, this seems intriguing to me, going forward:

Yes i wondered if it kept going North it could split the Artic north pole apart lol, maybe i am going mad but this year is crazy.

Yep your going mad...

As others say, now the storm is weakening and forecast to move near to Greenland, the weather in theory looks favourable for the ice but again with the way this year has gone then never rule anything out.

This looks like skating on very thin ice by august the 5th, link below.

https://www7320.nrlssc.navy.mil/GLBhycomcice1-12/navo/arcticict_nowcast_anim30d.gif
« Last Edit: July 30, 2020, 01:10:09 AM by glennbuck »

Rod

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Re: The 2020 melting season
« Reply #4128 on: July 30, 2020, 01:05:32 AM »


Yep your going mad...

As others say, now the storm is weakening and forecast to move near to Greenland, the weather in theory looks favourable for the ice but again with the way this year has gone then never rule anything out.

I am sorry Paul, but I have not seen a forecast that looks favorable for the ice in a very long time. The low is weakening and moving south, but that does not mean favorable conditions for the ice.

It has done whatever damage it was going to do. At a minimum, it pushed ice south into warm waters and reduced concentrations in the main pack. If it caused Eckman suction of warm deep waters that will be even more important.

We don’t know the outcome of the storm, or the reverse dipole that has flooded the CAB with heat from WAA. However, if you have a crystal ball that says the weather is now favorable for the ice please share that forecast with us.

Cook

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Re: The 2020 melting season
« Reply #4129 on: July 30, 2020, 01:38:24 AM »
The Beaufort low is clearly visible on Worldview today. Unusually clear spiral pattern.
This, is a terrifying image.

It exemplifies just how totally broken atmospheric circulation is in the northern hemisphere.

The import of this on weather in more densely inhabited latitudes is profound.

Would you care to elaborate on that? What is different about this low from other lows and how does it exemplify a broken atmospheric circulation? How is it important for weather in more densely inhabited latitudes.
I very much look forward to your reply since these are important questions that I don't have any answers to. I would appreciate it if you keep your reply simple, on a level that those with basic meteorological knowledge can understand. Thanks in advance.

jdallen

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Re: The 2020 melting season
« Reply #4130 on: July 30, 2020, 01:59:22 AM »
The Beaufort low is clearly visible on Worldview today. Unusually clear spiral pattern.
This, is a terrifying image.
<snip>
Would you care to elaborate on that? What is different about this low from other lows and how does it exemplify a broken atmospheric circulation? How is it important for weather in more densely inhabited latitudes.
<snip>

I think that question and discussion would best be carried on Here:
https://forum.arctic-sea-ice.net/index.php/topic,2692.300.html#lastPost

I think also that some of the weather professionals (and semi-professionals) would be better equipped to do so. 

The short answer is - it's structure and power are indicative of a global system of atmospheric circulation that is broken.

For more questions and answers, please ask/respond in the thread I just posted.
This space for Rent.

glennbuck

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Re: The 2020 melting season
« Reply #4131 on: July 30, 2020, 02:27:01 AM »
Ice thickness prediction from DMI, August 3rd, cutting into the arctic pole area down to between 9.84 inches and 19.84 inches of ice thickness.
« Last Edit: July 30, 2020, 02:37:06 AM by glennbuck »

D-Penguin

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Re: The 2020 melting season
« Reply #4132 on: July 30, 2020, 02:48:34 AM »
So, this seems intriguing to me, going forward:

Exactly the thought I expressed in my
« Reply #3935 on: July 28, 2020, 01:34:43 PM »
To posting by
BornFromTheVoid on July 28, 2020, 11:49:26 AM
Concentration for the 26th, 27th and both combined.

It was the contrast of the side-by-side graphic posted by BFTV that really aroused my curiosity.

I asked if anybody might have an explanation but nobody responded (everybody seems to be under the spell of the LP weather system over Beaufort at the moment).

With that LP system drifting east towards the CAA is it possible, even with reduced strength, it could begin to 'unzip' the arc of anomalously lower ice concentration right across the CAB!!!?
Remember...it's all about the Jet Stream you dummy...just a personal reminder!

ReverendMilkbone

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Re: The 2020 melting season
« Reply #4133 on: July 30, 2020, 02:49:22 AM »
Hycom ice thickness and extent for July 29 2012 and today; I knew this year was bad, but geez...

https://imgur.com/gallery/WdpJwUR


oren

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Re: The 2020 melting season
« Reply #4134 on: July 30, 2020, 03:10:48 AM »
Sorry to ruin the party again but Hycom thickness is not comparable between these years, the model has been changed several times since then, and 2012 has not been back-calculated.
BTW, DMI thickness is also not considered very reliable, again I would appreciate decreasing the frequency of posting it to the main thread.
« Last Edit: July 30, 2020, 04:27:57 AM by oren »

I’M IN LOVE WITH A RAGER

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Re: The 2020 melting season
« Reply #4135 on: July 30, 2020, 03:22:29 AM »
Sorry if this is ubiquitous and I just missed the boat, but is there one or a handful of consensus best thickness models/data and image sets to pay attention to in the summer? Hycom seems pretty decent intra-year unless I'm wrong there, but I was wondering if there is anything comparable or better out there to watch as well.

D-Penguin

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Re: The 2020 melting season
« Reply #4136 on: July 30, 2020, 03:38:14 AM »
Hycom ice thickness and extent for July 29 2012 and today; I knew this year was bad, but geez...

https://imgur.com/gallery/WdpJwUR

OMG makes this year look like a BOE compared to 2012,s ice thickness, 2012  29th July Thickness!

I think it was in 2014 on Neven's ASIB that I stuck my neck out and predicted the first BOE in 2020 +or- 4 years...I am not about to change my mind any time soon ;)
I even went further and predicted that after the first BOE <=4 years Ice Free Arctic Summer <= 4 years Ice Free Arctic Winter. So, a completely ice free Arctic by 2032 at the latest.

At the time, I think that the consensus scientific opinion would have put me about 100 years out on my predictions. The Science reminds me of the golfer who eventually gets his ball onto the putting green and then tells himself that if he can keep halving the distance to the hole with each put he will eventually be in a position to mark his score card for that hole.

Oh well and hecky thump and time will tell but at the moment I think the 'predictors' are leading the chasing pack of 'scientists' NOTE The IPCC Team didn't make the cut :o
Remember...it's all about the Jet Stream you dummy...just a personal reminder!

oren

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Re: The 2020 melting season
« Reply #4137 on: July 30, 2020, 04:00:26 AM »
Sorry if this is ubiquitous and I just missed the boat, but is there one or a handful of consensus best thickness models/data and image sets to pay attention to in the summer? Hycom seems pretty decent intra-year unless I'm wrong there, but I was wondering if there is anything comparable or better out there to watch as well.

Off the top of my head - but this is a very difficult subject:

* Hycom seems to have quite improved recently, there is a thread started by interstitial that contains discussion of Hycom and comparisons to other thickness products. But because of model changes over time the comparison to the past is problematic, hopefully this has now been fixed going forward. My current working assumption is that Hycom is a viable thickness model. I am not aware of an accompanying volume chart or a numerical product, just the animated map and 7-day forecast.
* PIOMAS was usually considered the standard since I came to the ASIF, the model is more transparent with various numerical outputs (analyzed by Wipneus and others in the PIOMAS thread) and has good comparison between years. However it is especially painful because it is only updated twice a month. OTOH, it used to be once a month, so life is good. Like all models, it has its own problems and artifacts, some driven from NSIDC artifacts, and has an over-focus or maybe over-abundance of pressure ridges that may or may not be justified. It was validated against real-life thickness measurements back in the 2000s, but impossible to know if the calibration is still correct.
* Cryosat/SMOS is considered the standard for a measured thickness product, but is only published until mid-April. If I am not mistaken it makes some assumptions about snow thickness, surface wetness and ice salinity but is quite reliable.
* NASA's Operation IceBridge measures the ice by radar from an airplane. Naturally limited in time and space.
* The new IceSat2 should be the new gold standard of measured thickness products, but I haven't seen the data coming out of the project. See long quote below.
* DMI thickness and volume are quite colorful but not considered very reliable, for example due to weird behavior around the minimum.
* AMSR2 JAXA has a measured thickness product and volume, not reliable at all in summer.

Bottom line, in the context of this thread, of the summertime volume charts available:
DMI is not good but could be useful for comparisons from time to time.
AMSR2 is almost meaningless.
PIOMAS considered reliable.

I have quoted the below link in full, this is best discussed elsewhere but is good for the education of the readers here.

https://www.nasa.gov/feature/goddard/2020/icesat-2-measures-arctic-sea-ice-thickness-snow-cover

Quote
NASA’s ICESat-2 Measures Arctic Ocean’s Sea Ice Thickness, Snow Cover
Arctic sea ice helps keep Earth cool, as its bright surface reflects the Sun’s energy back into space. Each year scientists use multiple satellites and data sets to track how much of the Arctic Ocean is covered in sea ice, but its thickness is harder to gauge. Initial results from NASA’s new Ice Cloud and land Elevation Satellite-2 (ICESat-2) suggest that the sea ice has thinned by as much as 20% since the end of the first ICESat mission (2003-2009), contrary to existing studies that find sea ice thickness has remained relatively constant in the last decade.

ICESat-2 has a laser altimeter, which uses pulses of light to precisely measure height down to about an inch. Each second, the instrument sends out 10,000 pulses of light that bounce off the surface of Earth and return to the satellite and records the length of time it takes to make that round trip. The light reflects off the first substance it hits, whether that’s open water, bare sea ice or snow that has accumulated on top of the ice, so scientists use a combination of ICESat-2 measurements and other data to calculate sea ice thickness.

By comparing ICESat-2 data with measurements from another satellite, researchers have also created the first satellite-based maps of the amount of snow that has accumulated on top of Arctic sea ice, tracking this insulating material.

“The Arctic sea ice pack has changed dramatically since monitoring from satellites began more than four decades ago,” said Nathan Kurtz, ICESat-2 deputy project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The extraordinary accuracy and year-round measurement capability of ICESat-2 provides an exciting new tool to allow us to better understand the mechanisms leading to these changes, and what this means for the future.”

Arctic sea ice thickness dropped drastically in the first decade of the 21st Century, as measured by the first ICESat mission from 2003 to 2009 and other methods. The European Space Agency’s CryoSat-2, launched in 2010, has measured a relatively consistent thickness in Arctic sea ice since then. With the launch of ICESat-2 in 2018, researchers looked to this new way of measuring sea ice thickness to advance the study of this data record.

“We can’t get thickness just from ICESat-2 itself, but we can use other data to derive the measurement,” said Alek Petty, a sea ice scientist at NASA Goddard. For example, the researchers subtract out the height of snow on top of the sea ice by using computer models that estimate snowfall. “The first results were very encouraging.”

In their study, published recently in the Journal of Geophysical Research: Oceans, Petty and his colleagues generated maps of Arctic sea ice thickness from October 2018 to April 2019 and saw the ice thickening through the winter as expected.

Overall, however, calculations using ICESat-2 found that the ice was thinner during that time period than what researchers have found using CryoSat-2 data. Petty’s group also found that small but significant 20% decline in sea ice thickness by comparing February/March 2019 ICESat-2 measurements with those calculated using ICESat in February/March 2008 – a decline that the CryoSat-2 researchers don’t see in their data.

These are two very different approaches to measuring sea ice, Petty said, each with its own limitations and benefits. CryoSat-2 carries a radar to measure height, as opposed to ICESat-2’s lidar, and radar mostly passes through snow to measure the top of the ice. Radar measurements like the ones from CryoSat-2 could be thrown off by seawater flooding the ice, he noted. In addition, ICESat-2 is still a young mission and the computer algorithms are still being refined, he said, which could ultimately change the thickness findings.

“I think we’re going to learn a lot from having these two approaches to measuring ice thickness. They might be giving us an upper and lower bound on the sea ice thickness, and the right answer is probably somewhere in between,” Petty said. “There are reasons why ICESat-2 estimates could be low, and reasons why CryoSat-2 could be high, and we need to do more work to understand and bring these measurements in line with each other.”

With ICESat-2 and CryoSat-2 using two different methods to measure ice thickness – one measuring the top of the snow, the other the boundary between the bottom of the snow layer and the top of the ice layer – but researchers realized they could combine the two to calculate the snow depth.

“This is the first time ever that we can get snow depth across the entire Arctic Ocean’s sea ice cover,” said Ron Kwok, a sea ice scientist at NASA’s Jet Propulsion Laboratory in Southern California and author of another study in JGR Oceans. “The Arctic region is a desert – but what snow we do get is very important in terms of the climate and insulating sea ice.”

The study found that snow starts building up slowly in October, when newly formed ice has an average of about 2 inches (5 centimeters) of snow on it and multiyear ice has an average of 5.5 inches (14 cm) of snow. Snowfall picks up later in the winter in December and January and reaches its maximum depth in April, when the relatively new ice has an average of 6.7 inches (17 cm) and the older ice has an average of 10.6 inches (27 cm) of snow.

When the snow melts in the spring, it can pool up on the sea ice – those melt ponds absorb heat from the Sun and can warm up the ice faster, just one of the impacts of snow on ice.

For more information on ICESat-2, visit www.nasa.gov/icesat-2 or icesat-2.gsfc.nasa.gov

OffTheGrid

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Re: The 2020 melting season
« Reply #4138 on: July 30, 2020, 04:19:36 AM »
Sorry to ruin the party again but Hycom is thickness is not comparable between these years, the model has been changed several times since then, and 2012 has not been back-calculated.
BTW, DMI thickness is also not considered very reliable, again I would appreciate decreasing the frequency of posting it to the main thread.

Ah ok thanks for the info found a 2015 Hycom seems more compatible now they have fixed it, still a sucky year 2020. I Prefer data from small democratic socialist countries like Denmark and Finland, large democratic countries data is manipulated in a lot of cases it seems.

It could be argued that in a fast changing arctic, Its the models that are not updated that provide the poorest comparisons with past years. 2012 cleared out most of the years old hardened Ice. The sort capable of forming large pressure ridged fields. Unseasoned young ice, or waterlogged the previous summer is as little as ten percent as strong as fully brine excluded ice. The very rare legacy floe Mosaic used could be considered best case. May have spent many years hardning as fast Ice in the outer Siberian islands, yet the core of Its 7 m pressure ridge failed to fully freeze all winter.
On  about the best drift path it could have had.
 When they first picked it up it was waterlogged from base near to sealevel.
DMI is another example which seems to drift further from reality every year. Now showing up to three meter ice when the nearest has been slush hundreds of km further out to sea for weeks.

I’M IN LOVE WITH A RAGER

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Re: The 2020 melting season
« Reply #4139 on: July 30, 2020, 04:43:57 AM »
Thank you oren for all the useful information! I appreciate the in-depth response!

Juan C. García

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Re: The 2020 melting season
« Reply #4140 on: July 30, 2020, 05:28:00 AM »
A quick view, after the worst part of the storm...
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.

Jim Hunt

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Re: The 2020 melting season
« Reply #4141 on: July 30, 2020, 06:23:25 AM »
It sounds like she/he will get to it eventually but it is not a priority.

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Freegrass

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Re: The 2020 melting season
« Reply #4142 on: July 30, 2020, 06:26:34 AM »
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
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ArcTickTock

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Re: The 2020 melting season
« Reply #4143 on: July 30, 2020, 06:34:42 AM »
A quick view, after the worst part of the storm...

How did the 2012 GAC look on false color as a comparison?  I am a relative newby and did not start following the melt season till a couple of years later.  Is that available to look up on the Bremen site?

binntho

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Re: The 2020 melting season
« Reply #4144 on: July 30, 2020, 06:37:47 AM »
Is it just me or do others get the shudders when they see that Will elf? Sorry, OT.
because a thing is eloquently expressed it should not be taken to be as necessarily true
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oren

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Re: The 2020 melting season
« Reply #4145 on: July 30, 2020, 07:20:02 AM »
Some updates:
* OSI SAF ice drift shows CAB ice racing towards the now empty Laptev and ESS. Some of the Beaufort ice is pushed back into the CAB, and some is dispersed south.
All this moving around can't be good for the ice and surely increases bottom melt.
* UH AMSR2 area of the four regions expected to participate in the minimum. CAB and CAA are tracking low, Beaufort tracking high but a cyclone-related blip is worrying. Greenland Sea tracking high but with export halted, area should drop sharply soon.
* CAA max temps as measured in various ground stations have gone down a notch since a few days ago, but are still warm enough for continued vigorous melt.

Click to enlarge images.



BornFromTheVoid

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Re: The 2020 melting season
« Reply #4146 on: July 30, 2020, 07:34:45 AM »
An update on the storm and concentration comparison. Higher res version on twitter.
https://twitter.com/Icy_Samuel/status/1288708042951929857

(click to play)
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

budmantis

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Re: The 2020 melting season
« Reply #4147 on: July 30, 2020, 07:35:34 AM »
Is it just me or do others get the shudders when they see that Will elf? Sorry, OT.

Yes, it does!

oren

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Re: The 2020 melting season
« Reply #4148 on: July 30, 2020, 07:38:42 AM »
Hello budmantis, it's been a while.

aslan

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Re: The 2020 melting season
« Reply #4149 on: July 30, 2020, 07:42:05 AM »
About wave activity, it can be noted that Indian Ocean was a strong source until lately. Pacific convection was a bit muted, but a dipole dominated over Indian Ocean, and a stationary MJO stucked in phase 2- 3 in June and July, with propagation of a wave train over Pacific and a reinforced subtropical jet here. But what is really curious is the strong source of wave activity from Arctic. I mean, I really don't remember seeing such a source independently from the mid latitudes and tropics.