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Messages - 1rover1

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1
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: February 25, 2021, 10:15:12 PM »
Indeed very beautiful images

Enclosed are images of the SIS, SWT and the "future iceberg" in the north.

Click to enlarge

2
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: February 25, 2021, 09:29:44 PM »
Absolutely pristine sentinel-2 image today.

Looks like this berg in the north is about to pop, or already has.

3
Arctic sea ice / Re: What's new in the Arctic ?
« on: February 23, 2021, 07:59:24 PM »
      Cloud-Making Aerosol Could Devastate Polar Sea Ice
https://www.quantamagazine.org/cloud-making-aerosol-could-devastate-polar-sea-ice-20210223/
1st paragraph:
     "To climate scientists, clouds are powerful, pillowy paradoxes: They can simultaneously reflect away the sun’s heat but also trap it in the atmosphere; they can be products of warming temperatures but can also amplify their effects. Now, while studying the atmospheric chemistry that produces clouds, researchers have uncovered an unexpectedly potent natural process that seeds their growth. They further suggest that, as the Earth continues to warm from rising levels of greenhouse gases, this process could be a major new mechanism for accelerating the loss of sea ice at the poles — one that no global climate model currently incorporates."   

4
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: January 21, 2021, 05:26:06 PM »
New small perpendicular crack in the SWT is growing, and if it reaches the first parallel crack, a large piece will calve.
nice catch, but just to be clear that is the Southern Ice Shelf (SIS) not the Southwest tributary (SWT) although it may be a moot point soon enough.  See the labels below.

5
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: January 12, 2021, 07:44:21 PM »
To finish these posts related to the PIG/PIIS speeds I wanted to point out that the site "http://www.cpom.ucl.ac.uk/csopr/iv/index.php?glacier_number=3" gives access to a zip file containing the text files containing the data related to the "Along-Flow" and "Across-Flow" speeds from 22/11/2015 to 31/12/2019 (not recent data!)
But the site allows an individual download of the files of the first half of 2020.

You will find below two diagrams related to the 22/06/2020 for comparison: the one provided by the site and the one calculated from the data provided by the site and using a rolling average over two km.
I find that the gain of information that we have by constructing the graph is not exceptional and that therefore, taking into account that we do not have the most recent data, we can limit ourselves to using the diagrams provided.

But in the zip I also found images of the PIG/PIIS (1km per pixel) from 14/06/2017 to 31/12/2019 (there are other earlier images, but they don't cover the front) that can be useful to create animations or for studies on the last years.

Click to enlarge

6
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: January 12, 2021, 03:44:14 PM »
PIG Along-Flow, Across-Flow ice speed and Ice Velocity from Images Pairs since may2018
http://www.cpom.ucl.ac.uk/csopr/iv/index.php?glacier_number=3
Quote
Hogg, A., A. Shepherd, N. Gourmelen (2015) A first look at the performance of Sentinel-1 over the West Antarctic Ice Sheet, FRINGE 2015, Frascati, Italy, 23-27 March 2015.

All best viewed at half speed.

7
Helheim Gletscher: A large calving session happened between December 23 and December 29 2020.

Please click on image to enlarge and animate!

8
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: December 25, 2020, 08:15:35 PM »
There has been a lot posted here about the Southern Ice Shelf, so I thought I would review recent developments and the implications for Pine Island Glacier.

First is a 30-day GIF of the developing rifts on the Southern Ice Shelf.  Movement has been pretty much continuous, so it would appear that a significant calving is becoming imminent.

The Southern Ice Shelf (SIS) is being pushed from the West by the Southwest Tributary (SWT) and supports the "T11" Tributary as it is merges with the main trunk of the Pine Island Glacier (PIG.)  Ever since the PIG Ice Front retreated from its merger with the SWT, the SIS has been weakened by rifts and calving.  The danger is that the loss of SIS will weaken T11.  In particular, the current SIS rifts (red) could extend to the T11 (orange) leading to more calving at the end of T11 (yellow.)

Even a temporary retreat of T11 could lead to the upstream rifts in the Southern Shear Margin (SSM) spreading downstream and which could speed up and weaken the PIG.  Further retreat of the PIG ice front could result in a permanent disconnect between the PIG and T11 just as has occurred with the SWT.

This could also affect the Northern Shear Margin (NSM) if the loss of contact with T11 causes the NSM to pull further away from the stationary Evans Knoll grounding line.

9
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: December 24, 2020, 05:51:25 PM »
Today's 6-day GIF of the widening rifts in the Southern Ice Shelf.

10
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: December 17, 2020, 04:50:03 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

December 16th, 2020:
     11,324,169 km2, a century break increase of 104,454 km2.
     2020 is 2nd lowest on record.
     In the graph are today's 10 lowest years.
     Highlighted the 5 years with daily lowest minimum on September.

Source: https://ads.nipr.ac.jp/vishop/#/extent.

11
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: December 13, 2020, 07:33:16 PM »
It is with delay, but the Sentinel2 images of the 11th finally arrived and they are of quality!
Apart from the NSM and the "SIS rifts" there were no big changes, so I post only the animations related to these 2 points

Click to animate

12
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: December 12, 2020, 09:10:30 PM »
SIS rifts update:

All rifts widen and WmR3 and WmR4 expand, WmR4 ending in a family of parallel rifts and the WmR3 is reconnecting to these rifts.

For the animation I use the Sentinel1 images from 30/11 and 12/12

Click to animate and zoom

13
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: December 06, 2020, 03:25:19 PM »
This 6-day GIF of the Southern Ice Shelf shows a pretty rapid expansion of the middle rift.

14
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: December 01, 2020, 11:38:51 PM »
Today's Sentinel2 image is good, even if it is not perfect like the one of 11/21.
It allows me to present you two animations:
> the first one is related to the SIS being shredded by the SWT
> the second one is relative to the NdD and, more precisely, to its right flank which is cracking more and more.

Click to animate

15
Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: September 18, 2020, 05:32:19 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

September 17th, 2020:
     3,734,834 km2, a 100K+ increase of 104,616 km2.
     2020 is 2nd lowest on record on this date.
     Highlighted 2020 & the 4 years with a daily lowest min in Sept. (2012, 2019, 2016 & 2007).
     In the graph are today's 10 lowest years.
     Source: https://ads.nipr.ac.jp/vishop/#/extent

P.S. The melting season is officially over!  ;)

16
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: July 29, 2020, 09:23:50 PM »
I wanted to add a lighter version:
with two intervals of 24 days: 17/02, 12/03 and 05/04,
and three intervals of 36 days: 05/04, 11/05, 16/06 and 22/07,
and adding little comments.

Click twice to zoom in



17
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: July 28, 2020, 02:54:12 PM »
Here is a higher-resolution 6-day GIF of the Northern Shear Margin, but the images are from different angles so beware the radar shadow artifacts.  I think it shows the calving is just some of the melange getting lose.

18
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: July 28, 2020, 04:51:01 AM »
12-day GIF of the Southern Shear Margin.  Nothing too surprising compared to the one from July 22.

19
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: July 22, 2020, 02:10:49 PM »
Almost missed the new rift on T11 (Tributary 11) which may prove worrisome.  We've been pinning our hopes on it becoming the new 'pinning point' in the South, but this is its first sign of potential vulnerability.

20
Antarctica / Re: Pine Island Glacier (PIG) Calving and Discussion
« on: July 07, 2020, 02:41:13 PM »
Very useful to have analysis on this
but for reference it's sort of done automatically already
http://www.cpom.ucl.ac.uk/csopr/iv/index.html?glacier_number=3&image_date=200616_200622#output

21
Arctic sea ice / Re: The 2020 melting season
« on: June 28, 2020, 11:36:51 PM »
As others have have said the euro forecast is amazing.

It's not a dipole anomaly.

It's worse.

It's THANOS with the INFINITY GAUNTLET WITH ALL 6 STONES ABOUT TO SNAP THE ICE OUT OF EXISTENCE.

The 12z euro below from day 2 to day 10.

Might have to click to animate.  Never going to happen.

But if it does the best part will be the clear sky modis images of almost the entire basin.

22
Antarctica / Re: Sea Ice Extent around Antarctica
« on: March 31, 2019, 12:16:44 PM »
JAXA ANTARCTIC Sea Ice Extent : 4,011,238 km2(March 30, 2019)

Extent gain has mostly at or below average in the last week.

- Extent GAIN on this day 65k, 25 k less than the average gain of 90 k on this day.
- Extent is 2nd lowest in the satellite record for this day, 464 k above extent on this day in 2017.
-  Extent gain from minimum is 1,587 k, 841k (35%) less than the average of 2,428 k by this day,
- 15.0% of the freezing season done, with 170 days to average date of maximum (16 Sept),

The Perils of Projections
Remaining average freeze of last 10 years gives a max of 17.63 million km2, 430k less than 2017 (record low max year).
______________________________________________________________________
I will only be posting occasional updates from now on unless something of note occurs.

23
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: March 31, 2019, 07:00:59 AM »
[ADS NIPR VISHOP (JAXA)] Arctic Sea Ice Extent.

March 30th, 2019:
     13,423,101 km2, a century drop of -165,712 km2:o
     2019 is the lowest on record.
     (2012 highlighted)
 

24
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: March 31, 2019, 06:07:18 AM »
A JAXA extent loss of -165712 km^2 today drops the extent over {150K corrected} 137K below the previous record for the day. This is the lowest March value since at least 2002. It is also the second largest single day loss for March.  Yesterdays drop of 113K was the 6th largest drop.
 

25
Antarctica / Re: Halley base shut down and new crack in Brunt shelf
« on: March 29, 2019, 06:36:44 PM »
Reporting in the New York Times 28 March:
An Iceberg Twice the Size of New York City Is About to Split From Antarctica: Two rifts on the Brunt Ice Shelf in Antarctica are close to creating an iceberg over 560 square miles in size. Scientists say the calving event could happen any day now.
https://www.nytimes.com/interactive/2019/03/28/climate/antarctica-brunt-iceberg.html

brief but good graphical presentation ...

I think A68 calved in winter. Is it a thing, that as it gets colder the calving potential continues? If so, for how long? Might be, answer is, nobody really knows, just sayin' ... [ocean temps lag a lot, for example in Boston it's just beginning to warm up a tiny bit, over 3 months later]

26

...
Moreover values were not used for the full arctic (60-90N).

While I agree that accuracy is important, and appreciate Zeke's work on this, it really is obscene to be carrying on this debate as though we're still serious about the possibility of keeping warming well below 2C given what other recent studies have said, and the early results for ECS from CMIP6.

...

wdmn,

I generally do not have time to address most of the assumptions that work their way into various posts in this thread, but I thought that I would clarify my position on some of the matters that you raise.

First, the Arctic Circle is from 66° 33' 39" N. to 90oN, so the plot you referenced is more relevant than Zeke Hausfather's; and I was merely pointing out that different posts were comparing apples to oranges.

Second, in Zeke Hausfather's following linked article on the SSP scenarios, he notes that SSP2 is most comparable to the relatively new RCP 7.0, and he claims that these scenarios are more likely to be more representative of future anthropogenic forcing than either SSP5 baseline or RCP 8.5.  However, before the end of April 2019 global population will be at 7.7 billion people, which is above all of the SSPs estimated global populations in 2019 as shown in the first image from Hausfather's article, and I note that in 2100 RCP 8.5 assumed a world population of about 12 billion while SSP5-baseline assumes a world population of about 7.38 billion people (indicating that SSP5-baseline was rigged to match the radiative forcing of RCP 8.5, significantly by ignoring global population projections).  Thus SSP5-baseline seriously underestimates global population, which means to me that even if the people ignored by SSP5-baseline were to only use sustainable energy (see the second attached image for the year 2018) then we would still be following SSP5-baseline and not SSP2.

Title: "Explainer: How ‘Shared Socioeconomic Pathways’ explore future climate change"

https://www.carbonbrief.org/explainer-how-shared-socioeconomic-pathways-explore-future-climate-change

Extract: "While RCP8.5 lives on in the form of the SSP5 baseline, it is now just one of many possible no-new-policy futures. The fact that only one of the SSPs, SSP5, can reach the level of emissions found in RCP8.5 suggests that it may not now be best suited for use as the sole baseline scenario in future research.

If any SSP can be said to be characteristic of current conditions it is SSP2, where social, economic and technological trends do not shift markedly from historical patterns. Greenhouse gas concentrations in the SSP2 baseline roughly correspond to the new RCP7.0, which shows lower emissions and nearly 1C less warming than RCP8.5 – though still 3.8-4.2C of warming above pre-industrial levels."

The second image comes from the IEA report on global energy use thru 2018 at:

https://www.iea.org/geco/

Finally, I remind readers that I think that we will only follow SSP5-baseline through circa 2060 when I expect global socio-economic collapse will drop anthropogenic GHG emissions down to something like SSP1.

Best,
ASLR

27
Antarctica / Re: Halley base shut down and new crack in Brunt shelf
« on: March 18, 2019, 08:34:16 AM »
Yesterday we finally got a new clear Sentinel 2 shot.

Crandles got it right, the crack has not completed yet.

28
Antarctica / Re: Halley base shut down and new crack in Brunt shelf
« on: March 07, 2019, 04:38:19 PM »
Looks like crack might be complete at resolution shown.

Zooming in a little more, I am not even sure of the cracks marked with lines drawn above and or right of feature. Is interpreting more cracks justified?

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