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Neven

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Re: The 2017/2018 freezing season
« Reply #550 on: January 03, 2018, 12:54:38 PM »
Here are the surface temperatures for the four Arctic quadrants, all up from last year, except for Atlantic.

Ranking for this year (since 1948):

Atlantic 7th highest
Siberian 6th highest
Pacific 1st highest
Canadian 8th highest
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Neven

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Re: The 2017/2018 freezing season
« Reply #551 on: January 03, 2018, 10:48:08 PM »
NH snow cover is also interesting right now:
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Dharma Rupa

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Re: The 2017/2018 freezing season
« Reply #552 on: January 04, 2018, 12:54:52 AM »
NH snow cover is also interesting right now:
Down???

That is very interesting..., and I'm not sure of the correct way to take it.  Is there less humidity all of a sudden?

Yuha

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Re: The 2017/2018 freezing season
« Reply #553 on: January 04, 2018, 01:41:16 AM »
NH snow cover is also interesting right now:

According to Rutgers Snow Lab, Eastern Europe is the main area lacking snow.

Neven

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Re: The 2017/2018 freezing season
« Reply #554 on: January 04, 2018, 09:03:14 AM »
Indeed, the multisensor snow cover graph for Eurasia is even more explicit:
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Pavel

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Re: The 2017/2018 freezing season
« Reply #555 on: January 04, 2018, 09:14:55 AM »
The lowest tracking sea ice extent, snow cover, and the warmest December in the Arctic. Looks interesting, but the long night still continue. I wonder how it will go when the sun will come back

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Re: The 2017/2018 freezing season
« Reply #556 on: January 04, 2018, 10:12:45 AM »
NH snow cover is also interesting right now:

Interesting as in the old curse "may you live in interesting times" :-S

At least, on the positive side, there shouldn't be any direct link between E Europe snow in the region where it's less than normal and arctic sea ice.

Neven

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Re: The 2017/2018 freezing season
« Reply #557 on: January 04, 2018, 10:24:11 AM »
Interesting as in the old curse "may you live in interesting times" :-S

At least, on the positive side, there shouldn't be any direct link between E Europe snow in the region where it's less than normal and arctic sea ice.

Exactly, it doesn't mean much as of yet, although snow did play a significant part last year, IMO, in preventing record melt. And so it's just interesting, not 'interesting' (as in the old curse).

I can't wait to see the latest PIOMAS numbers.
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Ice Shieldz

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Re: The 2017/2018 freezing season
« Reply #558 on: January 04, 2018, 06:45:25 PM »
Hmm wondering about snowfall on sea ice (not necessarily land masses) as that will reduce sea ice thickening during winter. With the high amounts of precipitable water north of 65N, i thought there could be a good bit of snow on the sea ice.

Below is 2017 Lincoln Sea & Nares export from January to September. This video, was previously provided by A-Team as link. I am trying to embed it here on ASIF (not sure exactly how to do that or how to embed youtube videos)



Notice that from January-February 2017 the Lincoln Sea looses ice through the Nares and then stops between March-May, only to continue again though out the rest of the year.
« Last Edit: January 04, 2018, 07:07:47 PM by Ice Shieldz »

Neven

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Re: The 2017/2018 freezing season
« Reply #559 on: January 04, 2018, 06:52:19 PM »
I am trying to it embed here on ASIF (not sure exactly how to do that or how to embed youtube videos)

Just post the link and it will automatically be converted, no tags required.
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magnamentis

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Re: The 2017/2018 freezing season
« Reply #560 on: January 04, 2018, 07:28:29 PM »
NH snow cover is also interesting right now:
Down???

That is very interesting..., and I'm not sure of the correct way to take it.  Is there less humidity all of a sudden?

not less humidity but perhaps more rain instead of snow ?

jdallen

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Re: The 2017/2018 freezing season
« Reply #561 on: January 05, 2018, 05:46:37 AM »
NH snow cover is also interesting right now:
Down???

That is very interesting..., and I'm not sure of the correct way to take it.  Is there less humidity all of a sudden?

not less humidity but perhaps more rain instead of snow ?
Exactly my thoughts.  Cover may be down because cover may have been melted.
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Re: The 2017/2018 freezing season
« Reply #562 on: January 05, 2018, 06:43:32 AM »
Thanks for the Lincoln Sea Animation Ice Shieldz. That inspired me to go look if NASA still had the Worldview working, and I must say the 'compress scale'-feature on there is a great app. Night brightness T over Lincoln and High Nares. https://go.nasa.gov/2qra5MR and in case you get thrown to the unmodified scale adding the image (greenscale) (edit: oh, it looks like the shorthand link preserves the scale.) Note how the areas of clouds here show warmer brightness T than ice.
« Last Edit: January 05, 2018, 08:42:35 AM by Pmt111500 »
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Re: The 2017/2018 freezing season
« Reply #563 on: January 05, 2018, 02:22:17 PM »
NH snow cover is also interesting right now:
Down???
That is very interesting..., and I'm not sure of the correct way to take it.  Is there less humidity all of a sudden?
not less humidity but perhaps more rain instead of snow ?
Exactly my thoughts.  Cover may be down because cover may have been melted.
I have been tracking precipitation on Greenland. Since the beginning of November it has been average or well below average. I look at cci-reanalyzer to see what the next few days may bring.

The two images below show what my feeble memory says has been the case for some time, to whit, lots of weather in the Northern Pacific leading into the Bering Sea and Strait and lots of weather in the North Atlantic leading right up to Novaya Zemla. In contrast, the CAB, most of Siberia and Mainland N. America has been and is and will be(?) DRY.

Trouble is, that while there is easily accessible data on Northern Hemisphere snow cover, I as yet have found nothing on snowfall amounts, i.e. thickness ( reminds one of sea ice thickness v. extent?).

My point is, even if snow cover extent is average but thickness is in inches rather than feet, it will disappear quicker as spring arrives ?
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Neven

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Re: The 2017/2018 freezing season
« Reply #564 on: January 05, 2018, 02:35:05 PM »
Trouble is, that while there is easily accessible data on Northern Hemisphere snow cover, I as yet have found nothing on snowfall amounts, i.e. thickness ( reminds one of sea ice thickness v. extent?).

On the ASIG there's a NH snow depth departure (ie anomaly) map:



And a snow water equivalent map:



I don't know how they are made or how trustworthy they are. I believe it's difficult for satellite sensors to track this, as with sea ice thickness, but for other reasons.
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Re: The 2017/2018 freezing season
« Reply #565 on: January 05, 2018, 03:06:30 PM »
Trouble is, that while there is easily accessible data on Northern Hemisphere snow cover, I as yet have found nothing on snowfall amounts, i.e. thickness ( reminds one of sea ice thickness v. extent?).

On the ASIG there's a NH snow depth departure (ie anomaly) map:

And a snow water equivalent map:

I don't know how they are made or how trustworthy they are. I believe it's difficult for satellite sensors to track this, as with sea ice thickness, but for other reasons.

The images come from https://ccin.ca/home/ccw/snow/current   - Environment and Climate Change Canada Canada Snow Anomaly Tracking program

The methodology is described below - that includes a simple snow model as described in Brasnett (1999).

Quote
Data are derived from the operational global snow depth analysis run at the Canadian Meteorological Centre, Environment and Climate Change Canada Canada, since 1998. The CMC analysis is based on optimal interpolation of real-time climate station snow depth observations merged with background information from a simple snow model, as described in Brasnett (1999). This snapshot is a contribution to the Global Cryosphere Watch (GCW) programme of the World Meteorological Organization. (Brasnett, B. 1999. A global analysis of snow depth for numerical weather prediction, Journal of Applied Meteorology 38:726-740.)

There is other stuff e.g. a snow water equivalent graph that flatly contradicts my comment on the dryness of most areas prone to snowfall. Ho hum.
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Re: The 2017/2018 freezing season
« Reply #566 on: January 05, 2018, 03:30:01 PM »

Trouble is, that while there is easily accessible data on Northern Hemisphere snow cover, I as yet have found nothing on snowfall amounts, i.e. thickness ( reminds one of sea ice thickness v. extent?).

NOAA has the following, but, of course, that's only a fraction of North American snowpack: https://www.nohrsc.noaa.gov/snow_model/images/thumbnails/National/nsm_depth/201801/nsm_depth_2018010505_National_thumb.jpg 

Both ECMWF and GFS are hinting at a big warm-up in parts of E. North America in a couple weeks, so that might take a bite out of the snowpack there as well as undo some of the freeze up of the Great Lakes. https://www.tropicaltidbits.com/analysis/models/gfs/2018010506/gfs_T2m_us_51.png

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Re: The 2017/2018 freezing season
« Reply #567 on: January 05, 2018, 03:38:49 PM »
Meanwhile, still some open water in the Chukchi on the 4th of January according to 3.125 km resolution UH AMSR2 (which is also seen in the U Bremen product, inset). Also a very small amount in the Beaufort but as pull-away polynyas rather than hasn't-yet-frozen.

Green indicates the extent of solid ice (100% concentration). Here the image will display at full height with a click without opening a new tab. Ice thickness is also rather meagre for this date though there's considerable annual variability, second image UH SMOS 03 Jan 18. The same date is available for 2011-2017 as both full scale animation (needs a click to animate today) and small scale all-in-one.
« Last Edit: January 05, 2018, 05:45:01 PM by A-Team »

subgeometer

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Re: The 2017/2018 freezing season
« Reply #568 on: January 06, 2018, 10:17:11 AM »
The last few GFS runs on climate reanalyser are showing a succession of warm blasts coming in through Fram and over Greenland, the first in about 96 hours. Of course they can't be believed, but the one's  further out are successively more insane, with massive foehn winds bringing a huge area above freezing.

All the cold air is continually shunted into N America and Siberia

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Re: The 2017/2018 freezing season
« Reply #569 on: January 06, 2018, 10:35:52 AM »
Both GEFS and EPS ensembles are mostly in agreement on a synoptic setup that supports warm anomalies driven from subtropical advection on both the Atlantic and Pacific sides in the 5 day to 2 week mid range.

On the Pacific, a return of strong -EPO conditions starting around 5 days out will support another round of anomalies on the Pacific side. In the Atlantic, a strong pressure gradient along the NAO will transport subtropical moisture over the Greenland and Barents seas.

I've attached the 500hPa heights for GEFS and EPS in the mid range when both of these features are pronounced. The associated temperature anomalies for GEFS at this time are included as well. I would say these synoptic conditions have a very strong chance of verifying. The main question is what sort of duration each of these features will have.
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Shared Humanity

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Re: The 2017/2018 freezing season
« Reply #570 on: January 07, 2018, 05:17:38 PM »
When Dr. Francis 1st made headlines here with her jet stream analysis and the resulting slide towards sticky weather patterns, I posted some very long comments regarding my concerns about the emerging sticky weather that, due to my nearly complete lack of scientific knowledge, was very speculative, depending solely on a very layman's perspective.

The 7 day forecast you have just posted has caused me to want to post a similar comment, actually a question for this community.

First, my assumptions:

Dr. Francis is correct. The rapidly warming Arctic is resulting in a slower, more elongated jet stream and this trend will continue. Sticky weather will be a result. I believe the recent research is supporting her argument.

My concern:

This sticky weather will not be random but, in fact, will have a stickiness to it that is a result of the jet streams interaction with the complex topography of the northern hemisphere. This is already the manner in which northern hemisphere climate and long term weather patterns occur, a very direct linkage between topography (oceans, continents etc.) and the atmosphere. We thus get persistent regional climates like the deserts of the southwest U.S., the temperate climate of the British Isles, the fantastic phenomena of tornado alley which I happen to live in and I believe is the result of an interplay between the Rocky Mountain, the Great Plains, a warm Gulf of Mexico and the jet stream. Essentially, our existing climate across the northern hemisphere already demonstrates vividly a stickiness which is due to the linkage between our topography and the atmosphere.

So, what are the major northern hemisphere topographical features? The Pacific and Atlantic Oceans, the North American Rockies and Great Plains, The vast Eurasian landmass, the Himalayas, the icy expanse of Greenland and until very recently, the persistent icy Arctic. There are others I am sure (Ooops, the Mediterranean Sea).

All of us are intimately familiar with the local climate of our region and the effect of the interaction between the atmosphere and local topography. The temperate rain forest climate of the Northwestern U.S. and the previously mentioned tornado alley for example.

Sorry for the long post but the forecast just posted, I believe, is evidence of an emerging sticky pattern, high pressure ridges that frequently set up over the North Pacific and over the North Atlantic and persist over long periods and are a direct result of an increasingly strong topographical influence over a weakening jet stream where the Pacific Ocean and the Rockies and the Atlantic Ocean and, perhaps, the icy landscape of Greenland will cause sticky patterns.

Arctic cyclone cannons anyone? How about more frequent and stronger U.S. East Coast bombogenesis Nor'Easters and the desertification of the U.S. Southwest?

As the jet stream weakens, would it not be the case that topography will have a stronger influence on weather and climate, essentially begin to dictate more thoroughly the weather and climate and impose a stickiness that a stronger jet stream would often but, now, less frequently overpower?
« Last Edit: January 07, 2018, 05:45:20 PM by Shared Humanity »

aperson

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Re: The 2017/2018 freezing season
« Reply #571 on: January 07, 2018, 09:38:26 PM »
I'm not a meteorologist just a weather weenie, but here's my take:

I think some of our climate teleconnections represent fundamental modes of oscillation in our atmosphere (ENSO, EPO, NAO, AO), and some of our other climate teleconnections are linearly dependent on these fundamental modes (PNA). These teleconnections themselves were found by performing principal component analysis on 500mb geopotential height anomalies to determine which empirical orthogonal functions explain the most variance among 500mb geopotential height patterns (see: http://www.cpc.ncep.noaa.gov/data/teledoc/telepatcalc.shtml). Our primary teleconnections are the ones that manage to explain a significant amount of the variance on a month-to-month basis, e.g. they commonly show up in the top 10 dimensions of PCA.

The question of "sticky" weather patterns then becomes a question of how the indexes for these (hopefully) orthogonal teleconnections evolve over time. Their random walks should essentially slow down if that's the case, or indexes should fall into zones of stability and instability instead of being normally distributed.

I know this doesn't give you answers, but it may help phrase the question you're trying to ask.
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subgeometer

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Re: The 2017/2018 freezing season
« Reply #572 on: January 07, 2018, 10:55:23 PM »
The jetstream blows above a temperature contour on the surface - between cold/not cold or icy/melted, so as the winter temperature difference between the Arctic Ocean and the surrounding continents becomes greater with late refreeze, thin ice or none etc I expect to see more loops off the jetstream sheperding warm air into the basin. For now that should be most pronounced in the first half of winter while open water remains in the basin. Ie now the Chukchi Sea is frozen and as the Bering hopefully freezes perhaps the Pacific incursions will be less likely/extreme.

Edit: topography and the various climatic modes like AO etc obviously play a role as well

This is just a layman's take
« Last Edit: January 07, 2018, 11:12:17 PM by subgeometer »

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Re: The 2017/2018 freezing season
« Reply #573 on: January 08, 2018, 06:51:21 AM »
The -EPO and Strong NAO dipole patterns I mentioned earlier continue to be amplified on both GEFS and EPS ensembles. The resulting action of these creates a strong +DA (Dipole Anomaly) pattern that lasts from around τ=108 to τ=240 on the Jan 8 00z GEFS run. This pattern results in a substantial amount of warm air advection from the Eastern Pacific midlatitude region into the Arctic and across it toward the Atlantic side.

I have attached 500hPa height and anomaly plots at τ=168 as well as averaged temperature anomaly graphs across the aforementioned duration. I will be interested to see if this pattern continues to amplify. However, I suspect that we will still be at record low extent at the end of January because of the magnitude and duration of this torching event.

I have also noticed that reference EOFs for the +DA pattern are hard to find. They are available in Fig. 2 here: http://onlinelibrary.wiley.com/doi/10.1029/2008GL036706/full
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Re: The 2017/2018 freezing season
« Reply #574 on: January 08, 2018, 09:33:59 AM »
Given the strong MJO signal that is forcing the upper level jet to crash in the Central Pacific, I suspect that this pattern will be sticky once again.

I would put the over/under line for NSIDC Arctic Sea Ice Extent on Feb 1, 2018 at 13.4m km^2. And personally, I would take the under on this line.
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Re: The 2017/2018 freezing season
« Reply #575 on: January 08, 2018, 07:09:37 PM »
For those who have not seen this on Twitter: https://twitter.com/seaice_de/status/950023332015104001

Arctic sea ice apparent discrepancy resolved:



 Conclusion: thickness is the key for different metrics

(Click to start animation)

A-Team

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Re: The 2017/2018 freezing season
« Reply #576 on: January 08, 2018, 07:29:42 PM »
Nice. SMOS is probably the best single tool for monitoring progression of the freeze season. They don't provide any forecasts at this time though perhaps it could be integrated with NOAA's RASM-ESRL forty-frame ten days out when that resumes.

Just cross-posting to our automated script animation effort which is using PanoplyCL on daily UH SMOS netCDF files as its instance for range optimized display. The first post explains how to compare the same dates in various years via differencing map animations in Panoply, ImageJ or Gimp; the second how to optimize data to palette for visualizations.

https://tinyurl.com/yadgrfsq file repository
https://forum.arctic-sea-ice.net/index.php/topic,1259.msg138130.html#msg138130
https://forum.arctic-sea-ice.net/index.php/topic,1259.msg138256.html#msg138256
« Last Edit: January 08, 2018, 07:36:33 PM by A-Team »

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Re: The 2017/2018 freezing season
« Reply #577 on: January 09, 2018, 07:08:01 AM »
According to NOAA's NCEP/NCAR data 65N-90N December air temps at 1000mb set a new record, although seemingly not as much of a record as the 925mb temps illuminated in Neven's PIOMAS update: http://neven1.typepad.com/blog/2018/01/piomas-january-2018.html

https://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl

subgeometer

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Re: The 2017/2018 freezing season
« Reply #578 on: January 09, 2018, 11:05:49 AM »
According to NOAA's NCEP/NCAR data 65N-90N December air temps at 1000mb set a new record, although seemingly not as much of a record as the 925mb temps illuminated in Neven's PIOMAS update: http://neven1.typepad.com/blog/2018/01/piomas-january-2018.html

https://www.esrl.noaa.gov/psd/cgi-bin/data/timeseries/timeseries1.pl

This GFS reanalysis of december via climate reanalyser shows the ugly story of anomalies at surface level (click to animate)

A-Team

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Re: The 2017/2018 freezing season
« Reply #579 on: January 09, 2018, 12:38:09 PM »
Ice thinness on 08 Jan compared for the last 8 years; bulk ice salinity changes 01-07 Jan 2018. Both need a click-tab to display properly.

The available date range for UH SMOS is too short to speak about trends and anomalies but the last two years are showing considerably more thin ice for this late date in January than previous years, including the blow-out year 2012 (which is 2013 in January terms).

The issue of departure from climate normals is discussed in depth here:

https://forum.arctic-sea-ice.net/index.php/topic,2223.msg138433.html#msg138433
« Last Edit: January 10, 2018, 12:46:30 PM by A-Team »

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Re: The 2017/2018 freezing season
« Reply #580 on: January 10, 2018, 11:23:41 AM »
The latest discussion paper from the Norwegian young sea ice expedition:

"CO2 flux over young and snow-covered Arctic sea ice in winter and spring"

From the conclusions:

Quote
We measured CO2 fluxes along with sea ice and snow physical and chemical properties over first-year and young sea ice north of Svalbard in the  Arctic ice pack. Our results suggest that young thin snow-free ice, with or without frost flowers, is a source of atmospheric CO₂ due to the high pCO2 and salinity and relatively high sea ice temperature. Although the potential CO₂ flux through the sea-ice surface decreased due to the presence of snow, snow surface still presents a modest CO₂ source to the atmosphere for low snow density and shallow depth situations. The highest ice to air fluxes were observed over thin young sea ice formed in leads. During N-ICE2015 the ice pack was dynamic, and formation of open water was associated with storms, where new ice was formed. Open leads and storm periods were important for air-to-sea CO₂ fluxes (Fransson et al., 2017), due to undersaturation of the surface waters, while the subsequent ice growth in these leads becomes important for the ice-to-air CO₂ fluxes in winter due to the fact that the flux from young ice is an order of magnitude larger than from snow-covered first-year ice.

Amongst other things it also discusses the temperature and salinity profiles of Arctic sea ice snow cover:
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A-Team

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Re: The 2017/2018 freezing season
« Reply #581 on: January 11, 2018, 05:02:35 PM »
Ice pack motion -- and Fram export -- really picked up this fall and has continued into January 2018. It's easy to see but difficult to describe ice pack motion.

The pack has gotten much more fluid as first and second year ice has come to predominate. Wind circulation drives ice motion but the coupling depends on roughness and ridges and is resisted by ice keels. Ice motion in turn controls surface oceanic currents (though not those at depth such was western bathymetric boundary currents).

Watching the 2007 ice age video, another two weeks of that weather around the minimal extent would have resulted in a total ice blowout. That failure mode, which is a major alternative to the drip drip drip of the trend line, would have been 'premature' in the sense that Arctic Amplification of the air and Atlantification and Beringification of the portal seas had not progressed to the extent seen today and so would not have been able to sustain fall open water. (The Arctic Ocean is far too warm to seriously freeze once its stratification is stirred up.)

The ice is currently being exported as two merged streams of the last thicker ice. However it's not easy to draw an ice envelope over a 10 Sept 17 satellite image that shows which ice will be exported (or be in export position) by 11 Jan 18.

The problem here from the AI perspective is that feature-tracking tools like SIFT work best on consecutive days. However they aren't able to follow an initial tracking point over a season because point features don't have stable signatures. Small regional features do, and at least to the eye, remain recognizable even as they rotate and deform.

However the eye of even the dumbest person is a whole lot better at seeing this than the smartest AI.

Thus the issue of 'virtual buoys' is unresolved. With the advent of all-season Sentinel-1AB and its daily tiling up at DTU, the data is there to track ice motion at high resolution (if you like large files). However the 'line integral' problem of upgrading daily movements to buoy-like drift tracks has not been resolved on a seasonal or multi-year time scales.

Technical note: I've belatedly noticed that ImageJ has far better features for processing huge series of daily satellite images than Gimp. These are buried in sub-sub-sub menus of the Image menu and have to do with tiling (called montage), re-layering, adding date labels in clean text from constituent file names, allowing very fast simultaneous processing steps on all layers such as adding arrows, adjusting global contrast, enhancing local contrast, and ability to save out in greatly reduced file size as forum-shareable mp4.

Indeed the single best way of scanning an animation is simply mousing the slider back and forth just in the stack window. Here you can see immediately whether a project has an prospects of going anywhere, prior to doing the many subsequent steps.

The old-fashioned scatterometer images of ASCAT works quite well for ice pack movement. Here we could care less about its careful instrumental calibration of σ0. A lot of researchers don't get this: when trying to draw out feature recognizability, the information is in there, but the originals are highly sub-optimal for that purpose, whether following on with eye or AI. Below, adaptive contrast enhancement is piled on top of a conventional histogram stretch. ASCAT comes as rgb but is actually grayscale; were it in color like Sentinel-2AB white-on-white, decorrelated channel stretching would apply.

The mp4 below runs from the Sept minimum up to yesterday ... the caption shows day-number rather than calendar date. The epoch converter site tabulates these. The default forum mp4 setting is no-loop but that can be changed under the stop-start arrow. However there is no way to add a final frame delay other than high multiplicity in the original gif stack. The controller can be hidden and mouse-down will play or pause. 'Open video in new tab' results in an obligatory download at least in Opera. Copy-overs of mp4 posted elsewhere does not work in the manner of pngs or gifs.

Here parent gif was 695 pixels wide but for some reason the mp4 is going slightly out of bounds. (But at least it is playing and scrollable!) The 121 day file is just 3 MB at 150% resizing and high quality mp4 export so 2-3 years of continouse ASCAT could be displayed here, more by cutting to every 2nd or 3rd day. Note the quality of single day frames remains better in gifs.

Enhancements have been very successful here in suppressing some of the weather noise and promoting longer term recognizability of features. There's no Beaufort Gyre nor Transarctic Drift in sight though some days the wind pattern needed for the BG will set up on nullschool for a few hours.

See also the blow-up of the rotating block of ice along the CAA over at
https://forum.arctic-sea-ice.net/index.php/topic,416.msg138526.html#msg138526
« Last Edit: January 11, 2018, 09:24:35 PM by A-Team »

A-Team

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Re: The 2017/2018 freezing season
« Reply #582 on: January 12, 2018, 02:50:11 AM »
Here's a full year of ASCAT ice pack motion. Summer is a bit hard to follow because of atmospheric interference. Other than that, fascinating. It makes more sense to just compare fall to spring for various years so watch for that tomorrow. (And thx to a NOAA team for some timely help on file accessing side!)

Quote
Technical note: this is technically difficult to make because of the immense initial file size  prior to cropping down to the Arctic Ocean. Yet at the end, it is not a large file though not all web browsers seem able to display forum mp4. However download seems to work ok and can be viewed on your local movie player. Even Opera is showing an artifactual green stripe down the Fram that is not in the original file or its QuickTime representation. However a crop at the level of the original gif seems to cure this problem. Note the day-number is initially hidden under the inept controller.
« Last Edit: January 12, 2018, 03:26:08 AM by A-Team »

Tor Bejnar

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Re: The 2017/2018 freezing season
« Reply #583 on: January 12, 2018, 04:02:41 AM »
Both at home and at work I cannot watch mp4s due to lack of software.
(It didn't keep me from posting one, taken by a coworker's cell phone!)
Note: this is an image of a not working mp4, not a clickable icon.)
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Re: The 2017/2018 freezing season
« Reply #584 on: January 12, 2018, 04:09:16 AM »
Seems the way to make the forum play nice with embedding video is to upload the video to a youtube account and then paste the youtube video's 'share link' (not the embed link) straight into your forum message.

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Re: The 2017/2018 freezing season
« Reply #585 on: January 12, 2018, 05:16:48 AM »
The GFS is showing a storm passing just north of Svalbard which intensifies to 972hPa about 54hrs out and stays around that intensity for a day or so. It grows out of a pulse of moist warm air fired up by a low acting as a slingshot off the coast of Greenland

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Re: The 2017/2018 freezing season
« Reply #586 on: January 12, 2018, 06:10:19 AM »
The 500hPa gyre around Iceland is nuts. GFS has had the low pressure center of the system drop down as low as 926mb MSLP on recent runs which would put us on once-in-a-decade scales. That thing is going to have high uncertainty in intermediate range and isn't going to resolve cleanly until we're probably sub 36 hr out, but it's a real Arctic cyclone threat with the current synoptics. Sure would be nice to have more surface obs around that region so that our models would resolve better.

I also suspect that Rossby wavebreaks from the NAO dipole that it's driving are the source of the sudden stratospheric warming signal that's been showing up starting at the end of January on recent GFS runs.

On another note, GFS has also been showing multiple tropical systems forming in the Atlantic and EPAC (fortunately just phantom systems so far).
« Last Edit: January 12, 2018, 06:19:32 AM by aperson »
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Re: The 2017/2018 freezing season
« Reply #587 on: January 12, 2018, 10:39:52 AM »
Seems the way to make the forum play nice with embedding video is to upload the video to a youtube account and then paste the youtube video's 'share link' (not the embed link) straight into your forum message.

I changed a couple of things and installed a forum mod for mp4s to be attached and played. However, I can see/play some mp4 files, but not others. I don't know how to fix this.

But like A-Team says: you can always download them and view them locally.
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Re: The 2017/2018 freezing season
« Reply #588 on: January 12, 2018, 11:03:37 AM »
Quote
I cannot watch mp4s due to lack of software.
No computer, no web browser other than the phone's?
Quote
upload the video to a youtube account and then paste the youtube video's 'share link' (not the embed link) straight into your forum message.
Are not youtubes restricted to fixed length x width proportions? That would not work too well given Arctic Ocean shape. Then there is Twitter but their software has major weirdness issues.

It seems like movie formats are still a total tower of babel, dozesn of them. I think the problem is the codecs and patent troll law firms.

Be great if everyone could see the movies. They are about the only way that year-long ice time series can be shown as the file sizes get out of hand with gifs. For example, downsizing the 361 year of ASCAT to a 150 pixel postage stamp still requires 8 MB as a gif, close to forum limits but with horrific loss of quality.

The left half of the png shows the save options I have within ImageJ. There are none within Gimp. The right half shows some online file format conversion options. These often fail to work as advertised.

The mp4's may upload ok to youtube though there's been complaints online about that not working. Can someone with an account give the full year Ascat a try here?
« Last Edit: January 12, 2018, 11:47:26 AM by A-Team »

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Re: The 2017/2018 freezing season
« Reply #589 on: January 12, 2018, 11:04:45 AM »
More recent gfs runs don't have ptype mixing to rain as deep over the Arctic as subgeometer's attachment above. However, this cyclone looks like it's still going to be very deep and cause extreme issues for Fram ice due to wave action:

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Re: The 2017/2018 freezing season
« Reply #590 on: January 12, 2018, 12:49:52 PM »
Quote
cyclone looks like it's still going to be very deep and cause extreme issues for Fram ice due to wave action
Here are Fram and Nares export the last two years, from the mid-September minimum until January 11th. Again, way too large as gifs. To best view, turn controller off, loop to on, hit play.

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Re: The 2017/2018 freezing season
« Reply #591 on: January 12, 2018, 01:21:49 PM »
I had the same problem with the mp4s and the problem seems to be that it uses an older version of mp4 known as MPEG-4 Part 2:

https://en.wikipedia.org/wiki/MPEG-4_Part_2

This is not supported on my browser but a newer version known as H.264 or MPEG-4 Part 10 or MPEG-4 AVC is:

https://en.wikipedia.org/wiki/H.264/MPEG-4_AVC

Below is one of A-Team's mp4s converted to the new format.

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Re: The 2017/2018 freezing season
« Reply #592 on: January 12, 2018, 01:27:32 PM »
Yuha's version is working for me! Thanks!
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Re: The 2017/2018 freezing season
« Reply #593 on: January 12, 2018, 01:40:08 PM »
A-Team's mp4 are not viewable on my browser except by downloading, this new one is viewable directly.

Tor Bejnar

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Re: The 2017/2018 freezing season
« Reply #594 on: January 12, 2018, 02:03:29 PM »
I can download A-Team's recent mp4 (at least at work), but Yuha's doesn't work for me directly or via download!
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Re: The 2017/2018 freezing season
« Reply #595 on: January 12, 2018, 02:22:54 PM »
Here are Fram and Nares export the last two years, from the mid-September minimum until January 11th. Again, way too large as gifs. To best view, turn controller off, loop to on, hit play.

Below the last frame as at 11 Jan.

HELP ! What does the colour coding mean ? (OK, I am having an off day).

If it means depth of ice then 2018 is looking sicker than 2017.
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A-Team

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Re: The 2017/2018 freezing season
« Reply #596 on: January 12, 2018, 04:10:37 PM »
Quote
Yuha's doesn't work for me directly or via download!
Double ditto. Not compatible with Mac QuickTime Player.
Quote
HELP Ice looks sicker in 2017! What does the colour coding mean?
Nothing was intended other than binning the 256 grayscale colors into 16 arbitrary distinct colors (ie 8-bit to 4-bit) for purposes of possibly illustrating floe motion better. This was the most effective of the canned palettes in ImageJ. However now I see that it actually is a 'spectral' lookup table and so the colors do correspond to snow/ice surface dielectric ~ ice surface salinity ~ extent of brine exclusion ~ sea ice age ~ sea ice thickness. More or less, the more less the farther down the chain towards thickness.

In other words, the whiter grays tend to be older and thicker and so are shown more as reds and magenta. However to compare volume export, wipneus estimates that on Piomas forum; to compare years for the whole Arctic Ocean in January, SMOS is probably best.

Technical note: any 256-color palette -- and there are thousands of these used in climate science -- can be imported into ImageJ or Gimp. However, many dozens of palette formats are in use. Patent trolls don't sit on these but it is still a major nuisance to move color tables around because most software wants to be in RGB full color which is 24-bit rather than 8-bit. ImageJ is currently in ruins because of a bad update so an older version has to be used (which has no movie export of any kind!).

Of the five options for saving out video on my computer, only three of them would open on my computer. ImageJ itself cannot open mp4's it just saved! However it can open the file back up when the raw avi codec is used yielding, weirdly, a gif.

So it looks like .mov, .avi, and .mp4 are the most promising. Neven would have to enable attachment uploads and media playing for .avi and .mov to pursue this further.

I emailed some of these mp4's to myself as attachments and they ran fine. But that's not a good test because I use aapl Mail rather than the more common google gMail.

fram.mov
fram.wmv
Fram.flv
fram raw.avi
fram mpeg.mp4
« Last Edit: January 12, 2018, 07:27:59 PM by A-Team »

Yuha

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Re: The 2017/2018 freezing season
« Reply #597 on: January 12, 2018, 04:38:43 PM »
Here's a one last try with the mp4 format, this time converting it using HandBrake, which is a popular open source video conversion tool.

HandBrake actually produces a file with the extension .m4v, which is Apple's version of .mp4. The HandBrake manual says that you can just change the extension to .mp4 but this might not work with QuickTime. I'm posting it with .mp4 since the forum does not allow .m4v. Neven, is it possible to add m4v to the allowed file types?

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Re: The 2017/2018 freezing season
« Reply #598 on: January 12, 2018, 04:44:20 PM »
Quote
one last try with the mp4 format, this time converting it using HandBrake
Loads and plays for me on Opera and Chrome but oddly not Safari mac. Handbrake is at https://handbrake.fr/

Below, H.264 codec wants to put out a .mov but if I change that manually to .mp4 it seems to play ok but only loads as an attachment, does not play here. So I ran it by an online converter to get a legitimate mp4 that is playing for me at least. It has a modified controller that allows full screen display (which doesn't work for this postage stamp size image.) https://movtomp4.online/

Technical note: Something else that folks might find useful: if you can get the object into ImageJ, it has a very nice feature called montage that will make a single image of whatever rectangular dimensions you provide, for example 248 = 31 rows x 8 columns which takes better advantage of screen ratio. This is also the place to apply global contrast operations because you can test the effect on all the frames. It then offers un-montage which along with concatenate and combine, allows multi-years to be shown side-by-side.

The simple gif animation below shows ice thinness the other day, whole ocean and Fram/Nares views. The Beaufort, Chukchi and Svalbard areas still have significant areas of thin ice.(Unusual, not unusual, temporary, or not long even a time series to say -- a lot of known unknowns there.
« Last Edit: January 12, 2018, 05:32:54 PM by A-Team »

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Re: The 2017/2018 freezing season
« Reply #599 on: January 12, 2018, 05:16:35 PM »
if I change that manually to .mp4 it seems to play ok but only loads as an attachment, does not play here. So I ran it by an online converter to get a legitimate mp4 that is playing for me at least.

Exactly the same for me. The first file does not show but plays ok when downloaded. The second one works perfectly on both Firefox and Chromium.