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Messages - grixm

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1
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: August 07, 2019, 03:43:14 PM »
NSIDC Total Area as at 6 August 2019 (5 day trailing average)  3,666,090 km2

The 7 day turnaround has stopped.
On this day area loss close to average.
                        
Total Area         
 3,666,090    km2      
-529,881    km2   <   2010's average.
-513,403    km2   <   2018
-1,316,789    km2   <   2000's average.
         
Total Area Change   -65    k   loss
Peripheral Seas   -7    k   loss
Central Seas__   -58    k   loss
Other Seas___    0    k   gain
         
Peripheral Seas         
Bering _______    0    k   gain
Baffin  Bay____   -1    k   loss
Greenland____   -6    k   loss
Barents ______   -0    k   loss
         
CAB Seas         
Beaufort_____   -10    k   loss
CAA_________   -14    k   loss
East Siberian__   -18    k   loss
Central Arctic_   -10    k   loss
         
Kara_________   -2    k   loss
Laptev_______   -3    k   loss
Chukchi______   -1    k   loss
         
Other Seas         
Okhotsk______    0    k   gain
St Lawrence___    -    k   loss
Hudson Bay___   -0    k   loss
- Area loss 65 k, 5 k MORE than the 2010's average area loss of 60 k on this day.
- Total area 2nd Lowest, 197 k LESS than 2016, and 133 k MORE than 2012.

Outlook
We are now in the period of reducing daily area loss that that will slide to zero by mid-September.
On this day area loss average, close to 2016 and less than 2012 on this day.

Of note is:
- Only some of the seven seas of the High Arctic are losing seas ice area at above average daily rates.
- The Chukchi has slowed,
- The ESS & the Beaufort are losing area at a good clip,,
- The CAA should be really warm all this week again - and some rain. Also high daily melt.
- No or little Fram export - and Greenland area loss up again. This may change after a few days.
- the CAB had a low area loss and  is still above the 2010's average .

Area continues 'twixt 2012 and 2016.
________________________________________________________________________

2
Arctic sea ice / Re: The 2019 melting season
« on: July 29, 2019, 08:35:16 AM »
There's no Point in posting HYCOM, as they switched from ArCc to Glb Models since about 2017. Especially when making Comparisons.
Glb seems to indicate much less thicker Ice than the previously used ArCc Model.

3
Arctic sea ice / Re: The 2019 melting season
« on: July 18, 2019, 05:04:54 PM »
the value of pms .. Neven can read at his leisure and respond in kind rather than search for posts that may be 10 or 20 pages back when he returns or maty never read .. b.c.

4
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: July 16, 2019, 03:16:38 PM »
NSIDC Total Area as at 15 July 2019 (5 day trailing average) 5,221,614 km2
                        
Total Area         
 5,221,614    km2      
-603,733    km2   <   2010's average.
-712,418    km2   <   2018
-1,335,604    km2   <   2000's average.
         
Total Area Change   -92    k   loss
Peripheral Seas   -12    k   loss
Central Seas__   -69    k   loss
Other Seas___   -11    k   loss
         
Peripheral Seas         
Bering _______    0    k   gain
Baffin  Bay____   -5    k   loss
Greenland____   -3    k   loss
Barents ______   -4    k   loss
         
CAB Seas         
Beaufort_____   -9    k   loss
CAA_________   -9    k   loss
East Siberian__   -16    k   loss
Central Arctic_   -7    k   loss
         
Kara_________   -10    k   loss
Laptev_______   -6    k   loss
Chukchi______   -11    k   loss
         
Other Seas         
Okhotsk______    0    k   gain
St Lawrence___    0    k   gain
Hudson Bay___   -11    k   loss

- Area loss 92 k, 11 k LESS than the 2010's average loss of 103 k on this day.
- Total area Lowest, 273 k LESS than 2016, and 27 k LESS than 2012.

Area loss dipping below average, difference with 2012 narrowing, with 2016 widening.

Other Stuff
Weather
GFS  showing temperature anomalies in the range +0.9 to 0 degrees celsius over the next 10 days. Over the next 5, or even 10, days it looks like a fairly significant low sits over the central Arctic Ocean north of Central / Eastern Siberia and elsewhere a high sits in the North Atlantic and another high over Greenland. The strongish anticlockwise winds matching but opposite to the normal clockwise movement of the Beaufort Gyre are maintained, starting as northerly winds from the CAA and the North Greenland coast. Wind and rain also from the South up Baffin Bay into the CAA at least for the first few days.

What all this means for melt is.... ?
Is this weather pattern there for the long-term?

A cliff or not a cliff** See below
We are in the period of maximum daily area loss that lasts until late July.
Overall, Area losses in July to date above average.

It looks like Fram export has stalled, with most area losses in the arc from the ESS along the Russian shore and down to the Barents. The CAA is showing signs of melt strongly increasing.

It is definitely a steep downward slope

However, the ESS is not a slope, or a cliff. It is a yawning abyss, but is the yawn decreasing? YES

NSIDC 5 day Area could/would/should/will/will-not continue in pole position for about one week/two weeks/the rest of July/the entire remaining melt season (delete as applicable).
________________________________________________________________________
ps: Meanwhile, Extent loss was well below average. But daily extent loss just went up on this day. Switcheroo?

5
Arctic sea ice / Re: 2019 vs 2012
« on: July 16, 2019, 12:34:45 PM »
DMI's thickness model shows pretty different results to PIOMAS. Where PIOMAS has 2012 and 2019 pretty much tied for volume at this point, 2019 is lagging pretty far behind according to DMI: (click to play)

I asked what the difference between these models are in the PIMOAS thread and why no one seems to talk about DMI, didn't get a response.

DMI uses CICE (and HYCOM for the weather forecast), PIOMAS uses PIOMAS.

DMI is a model to predict extent, PIOMAS is a model to measure total volume. Either can be used for another purpose, but its rather more likely to be bad at it than its primary purpose.

DMI don't publish much on their model so my diagnosis of their weaknesses may miss something important and these weaknesses may not be the critical ones.

CICE is a model developed for GCMs which is portable into weather forecast models rather than climate models, and DMI isn't the only group that has had trouble keeping it numerically stable. (I reckon the stability issue probably arises from calculated salinity being extremely sensitive to measurement error in assimilated temperature.)  DMI publish on their model rather less than they tweak it, so its not possible to be sure just what they are doing at the moment, but last time I found something on it they were assimilating a large chunk of climatology as well as data.

DMI has an issue with melting momentum. They hit volume minimum too early and have a much too steep melting curve during the summer. I think this probably derives from their sea model being a weather forecast model rather than an ice melt model and heat that should be going into a near surface sea layer in June/July and getting back to the melt ice in August/September, is being put directly into melting ice.

If you use the same DMI model to compare 2012 and 2019, its probably not too misleading, but you need to be sure its a reanalysis of 2012 using the 2019 model, because otherwise you'll be looking at the difference between their 2012 model and their 2019 model rather than the ice. (and if its a big difference, you'll can't tell whether its real or whether the model is having one of the years in which it goes haywire)

6
Consequences / The Climatic Effects of a Blue Ocean Event
« on: July 13, 2019, 09:06:18 PM »
I have been finding it difficult to find information on the wider global impacts of a Blue Ocean Event, outside the likes of Paul Beckwith. Peter Wadhams and an odd few extremely reticent/conservative academic papers. Hopefully this topic will help bring together what knowledge there is. Impacts from the materials that I have been able to find have included:

- A collapse of the polar cell and ferrel cells with a resulting equible Northern Hemisphere climate
- A "polar cell" centred on Greenland (until that melts out) with very static jet streams and little seasonal variability
- A maritime environment in the Arctic that produces large precipitation on permafrost areas, which will then accelerate CO2/CH4 emissions
- Massive storms in the North Atlantic as the more rapid melting of Greenland creates a bigger, more intense, "cold blob" that contrasts with the warmer waters around it
- A general acceleration of climate change due to much lower Northern Hemisphere reflectivity
- More rapid melting of the Antarctic due to the climate "see-saw"
- Northward movement of the ITCZ rain belts greatly changing rainfall patterns (plus and minus) for some areas
- etc.

This is a paper I wrote on the subject a couple of years ago and its amazing how little research has been published in the interim.

https://www.resilience.org/stories/2017-06-21/the-impacts-of-an-ice-free-arctic-a-climate-paradigm-shift/

Seems to generally be "the Northern Hemisphere is f***ed" with a BOE. I have started looking at real estate in Ecuador (Cuenca seems to be very nice) and the Paraguay highlands! Others insights would be much appreciated.

7
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: July 08, 2019, 09:02:18 PM »
Is there any way to find out where the CAB losses are coming from?

At 2.8M km2, that bucket is ~ 1/2 of all that remains and we've lost almost 0.3M km2 in the last 2 weeks from the CAB.

Anyone with NSIDC connections?

NSIDC sea ice concentration images are here:

ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/images/2019.

Here's an animation for the past 4 weeks, showing how the ice in the CAB gradually turns from white to blue.  That is mainly due to the spread of melt ponds: NSIDC sea ice area cannot really distinguish melt ponds from open water. 


8
Arctic sea ice / Re: The 2019 melting season
« on: July 04, 2019, 10:12:01 PM »
 This is Sentinel 2 visible, over a zone of the Beaufort Sea West of Banks Island. Lucky these days was open skies (for image availability). Gif is big, I purposely made over 700, requires a click.
What I really like of these broken areas of melting floes is their multiscale character, like a fractal. The more one zooms in, the smaller floes appear is similar proportion to the bigger ones and so. It is the smallest ones that melt out in days or hours. A moderate storm accelerates this cascade from large to small floes, which finally dissipate by top, bottom, lateral melt and wave washing.

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