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Messages - A-Team

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Arctic sea ice / Re: The 2018 melting season
« on: March 22, 2018, 11:35:40 PM »
Have we talked about snow yet?
I looked at windytv which offers Arctic Ocean snow accumulation forecasts ten days out according to 9 km ECMWF. Snow accumulation might total a few cm depending on location (which is a lot more than we are expecting here in Tucson AZ at 91ºF/33ºC).

It is way too cold now for rain-on-snow but that is something we need to follow very closely, given what N-ICE2015 observed during the spring north of Svalbard. Lightning strikes too... there's an app for that; my neighbor up the road developed it! He complains though about the satellite, stationary orbit make angles bad already by Hawaii. However Alaska has its own resources in the Beaufort Sea area; lightning's made the news here before.

Winter snow conditions on Arctic sea ice north of Svalbard during the ...
by I Merkouriadi - ‎Cited by 5

Oct 25, 2017 - Winter snow conditions on Arctic sea ice north of Svalbard during the Norwegian young sea ICE (N-ICE2015) expedition ...... Thus, it is likely that the ice lenses over SYI were the result of surface melting or rain on snow. Another possibility for the formation of these lenses is glazing at the snow surface, due ..
The small creatures
Jun 23, 2015 - Thick ice and snow prevent sunlight from reaching the sea water, which is where the nutrients and the grazers are. Therefore, sea ice algae are usually found in higher concentrations at the bottom of the sea ice. However, during our observations on our home floes, during Leg 5 and 6, we have discovered ...

Snow depth is hard to measure
Blog: N-ICE2015

Jun 1, 2015 - The amount of snow and when it falls is changing, and most climate predictions suggest that more snow will fall in the Arctic as the climate warms, but later in the winter. In a warmer Arctic this snow could be very important to the fate of the sea ice.

Arctic sea ice / Re: The 2018 melting season
« on: March 22, 2018, 06:22:21 PM »
Hello newcomers: in years past, 'The 2018 melting season' has just been a short name for what was actually 'The 2018 Arctic Ocean sea ice melting season' forum, just like the freeze season forum. Note this forum sits in a sub-directory of the Arctic Sea Ice collection.

Do we need to open a separate forum this year called the 'The 2018 Arctic Ocean sea ice melting season'? Otherwise we are going to have thousands and thousands of off-topic posts here by September.

I for one have zero interest in home-baked opinions not accompanied by outside factual support.  Do you really know anything about Atlantic Water intrusion into the Svalbard region beyond what is already beautifully imaged and forecast at Mercator Ocean? Where could this knowledge possibly be coming from? 

It's not what you know (or pretend to know) but how you know it. Attach a link, an image, a journal DOI, cite your post-PhD oceanographic research, something ... otherwise go to one of over 1850 chat room forums to vent personal feelings about how climate change will play out.

People are certainly welcome to their own opinions but not to their own facts (or lack thereof).

Arctic sea ice / Re: The 2018 melting season
« on: March 22, 2018, 05:50:39 PM »
havoc with the Greenland Ice Sheet.
The long-running Greenland melt forum is located elsewhere.

Here is the thing ... mistake to treat the land Snow cover anomalies as causal.  Thermal transfer from air to ice is trivial compared to insolation and water.  Albedo over the oceans. Water temperature. Those are the main factors.

Right. The snow pack over Arctic sea ice will be increasing to mid-calf thickness in the Chukchi but remains minimal overall according to RASM ESRL. We won't have a refresh on snow density until early April. Albedo and insolation effects can only kick in ocean-wide after the pole hole is gone on March 29th (Modis Terra can image the entire Arctic). There are no melt ponds at this point.

Arctic sea ice / Re: The 2018 melting season
« on: March 22, 2018, 03:17:31 PM »
I am not keen on reading six months of data-free speculation on what conditions prevail in the Arctic Ocean based on home-town weather.

Do we know of model and observational data sources that track daily albedo, melt pond formation (none yet), snow depth, liquid and ice water paths in clouds, rates of bottom ice melting, radiative heat fluxes etc? If so, which are the most reliable, how were they made and vetted, what are the links, how should we represent them as forum graphics?

Here is one source of both daily data and short-term forecasts but amongst our 1375 members we surely know of others:

Here is an integrated CryoSat2 resource for Feb 2018; the next release will be on April 3rd.

Thx to Fish for the link suggestion below -- I'll take a look though it may not be independent of the links above. Note by using second forum button in second icon row, you can display an image without downloading it.

NOAA PSD's maproom has many useful maps including outgoing longwave radiation, but I'm not someone who downloads data and processes it myself. Here's where you can see many OLR maps:

Arctic sea ice / Re: The 2018 melting season
« on: March 21, 2018, 11:21:02 PM »
Ok, so who has a full set of actionable links to the best daily snow data sets?

I don't see a need for more generic bs about butterflies flapping their wings in the Amazon or snow cover of NH / land, sure it's all important but what we are looking for are snow depth maps at reasonable resolution, ie snow resting on Arctic Ocean sea ice as this is the AO melt season forum. In fact, better than canned maps is the netCDF data archive underlying the map, if we plan to compare approaches like we do with ice thickness.

Ok, so who has a full set of actionable links to the best daily AO albedo data sets?

Ok, so who has a full set of actionable links to the best daily AO melt pond data sets?

Ok, so who has a full set of actionable links to the best daily AO cloud data sets?

Arctic sea ice / Re: Latest PIOMAS update (March mid monthly update)
« on: March 21, 2018, 03:22:45 PM »
Here is a simultaneous comparison of Piomas to Ascat, SMOS thin ice, and CICE thick ice for 28 Feb to 15 Mar 2018. It will need a new tab to animate. Piomas is doing better in some areas but still is not fully consistent at good resolution to what we know from ice provenance and other thickness tools.

Again it's hard to understand, once the peripheral ice is gone, how Piomas volume could be doing better than 15-20% absolute accuracy in any given year for the Arctic Ocean proper and how inter-year volume comparison would fare any better (as gaussian error goes as the quadrature(, with consequences to trend line nuancing.

The png at bottom shows daily ice motion over the first 80 days of 2018. The late February wind storm leading to negative Fram export stands out quite clearly. Individual days are shown more clearly at OSI SAF; these are shown animated over at Page One of the 2018 melt season.

Arctic sea ice / Re: The 2018 melting season
« on: March 21, 2018, 10:53:53 AM »
north-east of Greenland, looks like it's still open water.
No, it froze over almost immediately and has stayed that way. While this follows from persistent cold air temperatures, the observational trick is to look for stable cracks ... these can only form when there is ice. DTU Sentinel-1AB cloud-penetrating radar is probably the best way to look at the area. WorldView has been beset with clouds over this particular spot that resemble open water visually; the VIIRS image below is from March 14th. That's no accident because very thin ice with rifts still transmits ocean heat and vapor effectively to the air leading to clouds. Ascat is somewhat fooled because the new ice is still very smooth (ie black shows lack of roughness) but open water is much more flashy because of weather-borne salinity.

Early 3.125 km UH AMSR2 sea ice concentration showed a patch of 'blue' but here you have to get the file open in something like Gimp with a non-contiguous color picker to pull out the true zero concentration regions (of open water).

About two-thirds of the new polynya ice is already headed out the Fram export door. The GFS wind forecast has this continuing, whereas the other third will be driven west in the direction of the Nares and CAA. The ice volume involved is well-captured by the negative region in wipneus's graph below.

Arctic sea ice / Re: The 2018 melting season
« on: March 21, 2018, 10:11:21 AM »
I am just staking out a final piece of real estate here on the first page to hold more year-to-date summary time series at a stable location, as it looks like the 3 slots above and the 12 graphics may not be quite enough.

This area will hold synchronized cross-silo products, typically 4 of the ones above in a 2x2 array. This allows various parameters to be more easily compared when the same date is shown at the same time, however this comes at the cost of half-resolution.

The placeholder below shows Piomas thickness combined with Ascat roughness for the last 16 days of March. Combinations with sea surface temperature, DMI thickness, and SMOS ice thinness will be posted in a bit. Shorter time frames can be posted frame by frame as gifs whereas longer time series have to be presented as movies to keep file size reasonable. That unfortunately involves lossy compression whereas the gifs retain all the data (if it is 8-bit or less).

Arctic sea ice / Re: The 2018 melting season
« on: March 21, 2018, 08:58:39 AM »
More winter pre-conditioning data relevant to summer 2018 melt season will be presented on this third bit of Page One real estate. The data summaries below will be periodically updated to serve as convenient reference files for newcomers to the site.

The third set of four of these will include various sea ice thicknesses from January 1st to the current date. The first is SMOS ice thickness (really thinness as it only shows ice to 0.5 m) from UniBremen. The scale will be added back in a bit.

The other SMOS ice thinness product from Hamburg is offered solely as a netCDF, which is better in many ways but is more arduous to animate than a png graphic. However Dryland has automated that process and we should have this time series shortly.

DMI offers a third ice thickness product based on the Los Alamos CICE model. That too comes as a png but requires a -45º rotation to re-orient it.

Piomas has a fourth ice thickness product that is thoroughly analyzed by wipneus on that forum. Here I will simply concatenate, crop and resize those bimonthly gifs.

Here is a set of links that are useful for reaching the source sites:

AMSR2 Hamburg sea ice concentration daily png

OsiSaf ice drift daily 2018 03 14-03 16.png

Hamburg SMOS ice thinness daily nc

Bremen SMOS ice thinness daily png

DMI_SST ice thickness daily 2018 03 11.png

DMI_SST ice surface temperature daily 2018 03 11.png

GFS/Nullschool wind/temperature/pressure 8x daily 5 days out 40 frames,83.00,1008/loc=0.100,83.690

Mercator Ocean daily + 9-day forecast

WorldView ice visible/infrared daily png,VIIRS_SNPP_Brightness_Temp_BandI5_Night

RASM-ESRL ice forecasts daily nc and gif

Cryosat ice thickness monthly

Arctic sea ice / Re: The 2018 melting season
« on: March 21, 2018, 08:56:45 AM »
I am just staking out more real estate here on the first page to hold more year-to-date summary time series at a stable location. These will be periodically updated and serve as basic reference files for newcomers to the site.

I'll add the best journal citations for people wanting to look more into details of how academic and agency climate scientists derive the files from satellite imagery.

The first four of these includes UH AMSR2 sea ice concentration from January 1st to the current date. This is similar to ice area and extent but has much higher nominal resolution, up to 3.125 km, and provides both a detailed land mask and a daily open water mask. This time of year, most of the Arctic Ocean has 100% sea ice concentration (pure white)so the time series mostly shows solid white. That will change though on the periphery as the melt season progresses.

On the technical side, it's feasible to change out the bright red for a less distracting color, change out the white to distinguish areas at less than 100% concentration, count and graph pixels of open water, add back the color key and so forth. Unfortunately the netCDF file is not georegistered and so the map cannot be redrawn without the lat,lon lines or switched to a linear gray palette.

Arctic sea ice / Re: The 2018 melting season
« on: March 21, 2018, 08:55:14 AM »
Winter freeze season pre-conditioning is important to summer melt season. I am just staking out some real estate here on Page One to hold year-to-date summary time series at a stable, easily navigable location, in the manner of wipneus on the piomas forum. These will be periodically updated and provide basic reference files for newcomers to the site.

Note there's considerable overlap with Neven's admirable collection of 81 sea ice graphics, the difference being only water vapor at bottom is animated and all are transient (not archived). Seven of these are not working this morning due to problems at various remote host servers.

All of the animations will use the standard NSIDC map of the Arctic Ocean: the polar stereographic projection about the north pole, with Greenland in the down position. The maps will be similarly scaled to forum bounds which amounts to 650 pixels between the Bering Strait and Svalbard.

The first four of these include Ascat radar scattering off the ice from January 1st to the current date. Ice roughness corresponds fairly well to both ice age and ice thickness. At an mp4 speed of 9 frames a second (ie 9 days), ice movement is exaggerated by a factor of 777,600.

The OSI SAF graphic of daily ice motion is very well done. Note it also shows open water and dodgy ice as two shades of blue, thus incorporating information that otherwise might come from UH AMSR2. The first 80 days of 2018 are shown below, both as an mp4 and as summary graphic.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: March 20, 2018, 09:57:39 PM »
forecast a warming soon on the Pacific side of the Arctic Ocean.
Maybe so but those beautiful "cloud streets" in the Barents (associated with cold winds of a meandering central anti-cyclonic high) will continue out to March 25th and beyond, per GFS.

Twitter can confuse these with with blowing Antarctic ice needles or katabatic Greenland winds but Zach notes correctly today these are parallel bands of cumulus clouds that form as cold winds from the north blow off the ice edge onto warmer ocean waters.

OK, but why now, why cumulus mediocris, and what causes the street banding? 

The temperature differential between cold air blowing off the ice and the sea surface water, either open leads or more commonly beyond the ice edge, can easily exceed 20ºC in March. Thermal columns of moist heated air rise off the sea surface until they hit a denser warmer lid of air (provided a temperature inversion is present).

As the thermals are advected downwind and sink or rise according to ambient density differences, they form parallel pairs of counter-rotating cylinders of air. On the upper surface of rising air, water vapor cools and condenses into flat-bottomed, fluffy-topped clouds (ie cumulus: On the downdrafts, condensates evaporate giving clear skies on the sides of the clouds, the banding.

Surprisingly, the alignment of vortices alone does not reliably indicate wind direction. Stably stratified environments have lines 30° off CCW to the left; only an unstably stratified (ie convective) situation has bands parallel to mean wind.

Cloud streets are technically called horizontal convective rolls. The most favorable conditions for them occur when the lowermost layer of air is unstable, driven by a moderate wind and capped by a stable inversion, a common situation when upper air is subsiding, such as under recently prevailing anticyclonic conditions. turbulent momentum flux in PBL

Cloud Streets over sea can be seen during synoptic scale outbreaks of cold, dry air from continents over a neighboring relatively warm ocean. This flow often occurs behind a Cold front. As the cold air leaves the land or ice surface it is modified by vertical transfer of heat and moisture from the underlying water surface. An inversion will be formed the base of which rises with the distance from shore. The formation of the inversion is, in many cases, stimulated by NVA and subsequent sinking motion in the stream upwind of the 500 hPa trough-axis. The transformation of the air mass eventually leads to the formation of clouds which, under certain circumstances, take the form of Cloud Streets, and develop roughly parallel to the wind direction. Further downwind from the outbreak, the unstable layer becomes deeper, the flow becomes more cyclonic and the streets develop into three-dimensional open cells. Near the upper-trough the convection is enhanced by PVA, resulting in the formation of enhanced cumulus and comma.

North Atlantic islands like Jan Mayen disrupt the flow of the wind and create spiral eddies patterns in the cloud streets called von Karman vortex streets. These have not been seen this March with SZ or FJL islands, presumably because they are less disruptive to air flow.

We've also been seeing "comma clouds" which are vortices or mesoscale eddies that occur when warm humid air wraps counterclockwise around the cold air, forming clouds as these air masses rise. Comma clouds are a leading indicator of a small-scale low-pressure system forming. In the absence of an inversion, polar lows can grow into strong but small-scale cyclones. March is a big month for both cloud streets and polar lows.[cal]/1200Z/wind/isobaric/1000hPa/overlay=off/orthographic=-45.00,82,1250/loc=2.5,83.00 nice example

New areas of polar lows over the Arctic as a result of the decrease in sea ice extent
E Zabolotskikh et al.

Mesocyclones can arise when new areas of open water appear. Polar lows don’t form over sea ice, so as the sea ice retreats, new ocean areas with relatively warm water are exposed to cold air outbreaks, the favored environment for polar low formation, the Kara Sea being a prime example. Zahn and von Storch 2013) predict the decrease in both number of polar lows in the Arctic and their
intensity in the future due to the faster air temperature increase relative to water temperature and therefore higher stability of the boundary atmospheric layer.

Street clouds represent very cold and dry air from above the sea ice transported out over the open ocean, ie cold air outbreaks. It's not uncommon to see 3-4 polar lows over the Barents Sea in comma cloud cyclone category. These are baroclinic, meaning the low near the surface is linked to a trough higher up in the atmosphere, with these not located on top of each other. This vertical structure displacement allows the two lows to work together and to strengthen each other.

Most polar lows start out as baroclinic but many develop a warm core and go barotropic, meaning the and near-surface and lows aloft are locked in phase and no longer help each other grow. For the polar low to intensify at this stage, it needs to get its energy from the warm ocean surface, as with tropical cyclones (hurricanes) energetics. However the Arctic Ocean surface is far too cold to admit  arctic hurricanes. (Adapted from

Arctic sea ice / Re: The 2017/2018 freezing season
« on: March 19, 2018, 08:19:11 PM »
Here is an update on the Beaufort-Chukchi shear, pop-up of NW Passage cork and wind leveraging of the whole CAA icepack about midway, open up parallel leads.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: March 18, 2018, 07:42:24 PM »
The main links I have been using recently are below. It's fairly easy to set up a web browser to refresh them each morning but a bit more to refresh a dozen 30-day time series as some need a passage through Panoply or enhancement and cross-silo multiplexing in ImageJ.

However Dryland et al are closing in on an interactive web page that will automate all of this for anyone that wants it, no graphics or computer skills needed as the code will be all under the hood.

The basic idea is to first generate context for the latest images and to have multiple takes on ice condition (evidentiary consilience) and only then go on to interpret developments. Right now, the main concern is freeze season pre-conditioning of melt season. (There are zero prospects for predicting melt season outcomes as the weather is too important yet largely unknowable.)

Ascat ice roughness daily 2018 075.gif

AMSR2 Hamburg sea ice concentration daily png

OsiSaf ice drift daily 2018 03 14-03 16.png

Hamburg SMOS ice thinness daily nc

Bremen SMOS ice thinness daily png

DMI_SST ice thickness daily 2018 03 11.png

DMI_SST ice surface temperature daily 2018 03 11.png

GFS/Nullschool wind/temperature/pressure 8x daily 5 days out 40 frames,83.00,1008/loc=0.100,83.690

Mercator Ocean dail + 9-day forecast

WorldView ice visible/infrared daily png,VIIRS_SNPP_Brightness_Temp_BandI5_Night

RASM-ESRL ice forecasts daily nc and gif

Cryosat ice thickness monthly

Arctic sea ice / Re: The 2017/2018 freezing season
« on: March 18, 2018, 06:39:06 PM »
Ascat radar scattering captures ice motion quite well in the Kara and Barents area; it is shown in conjunction with WorldView infrared in the first mp4. Ice flowing past Vize and Ushakov islands leaves lee streamers that conveniently record net transport; Ushakov is 445 km from Novaya Zemlya according to Google Earth WGS84.

DMI ice surface temperatures, not to be confused with 2m or 950 mB air temperatures, have gotten colder (lighter grays) under a weak but persistent high pressure driftingabout the central Arctic.

Ice thickness in the Kara will maintain meagre values however as new ice replaces the large areas of opening leads. Recall a 1000 km long tongue of Kara Sea ice was imported into the Arctic Ocean between 28 Nov 2017 and 09 Jan 2018 -- the new ice forming behind it lost those 42 days of mid-winter for thickening. Ice entering the Barents will prove short-lived as elevated surface water temperatures there have more than adequate energy to melt out incoming ice.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: March 18, 2018, 06:28:26 PM »
Some interesting developments: the Beaufort lift-off continues with 23,000 sq km of ice from the Northwest Passage about to join the Arctic Ocean (unusual import) and a strong shear line developing along the boundary with the Chukchi and ESS.

The GFS forecast depicted at nullschool sees the current cold clear weather pattern continuing through March 23rd.

The Kara sea ice will continue its spectacular wind-driven disintegration shown in WorldView VIIRS. Oceanographic conditions from Mercator Ocean show the Kara to be almost entirely shallow continental shelf (30m and 100m contours) strongly influenced in salinity and temperature by inflows from the Ob and Yenisev rivers (whose surfaces are still frozen).

Arctic sea ice / Re: The 2017/2018 freezing season
« on: March 16, 2018, 04:15:44 PM »
Kara business as usual
the bigger the cracks, the thicker the ice
Why do you two post wild personal speculation about Kara sea ice thickness when carefully calibrated daily online satellite data is just a click away? This forum is not a chat room, we try to link to supporting data rather than just opine and share primitive idées fixes.

Perhaps loop the Kara sea ice export mp4s below over and over until you get it, next consider the OSI ice movement, sea ice temperature and AMSR2 concentration displays posted just up-forum, maybe read the twenty previous explanations of what is going here, what is coming next and why it matters for melt season.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: March 15, 2018, 11:46:09 PM »
Kara Sea itself doesn't look much different to other years. It's at max extent and remains to be seen
You're joking, right?

The rest / Re: Russiagate
« on: March 15, 2018, 07:06:11 PM »
ignorant lazy chemically illiterate über-patriots frothing at the mouth as they beat the drums for another round of Cold War
Before posting more asinine comments about tammelin and novichok chemistry, be aware my first academic job, at the University of California, found me teaching synthetic organic chemistry at a time when my research concerned serine protease cascades only chirality-reversed from the target here. (Alert to non-US readers: America had a brief flirtation with science education, ironically after Sputnik.)

Unlike some of our proud patriots, I had no choice whatsoever in my parentage and could just as easily have been born into Swaziland, Swiss, Swedish, or Sumatran citizenship instead of Suburbian. In regards to climate change however, we are all in this together. There's no getting away from it in NZ, private islands, spaceships or whatever. This incident and the response to it will draw huge resources away into militarism that were better spent on mitigation of climate change, not that we were doing enough before.

Meanwhile, back at the fact-gathering stage, the lead UK investigator Bazu said yesterday many more weeks of work are needed to establish what happened. Right. They're still trying to lay out a time table of the Skirpals' movements and at what point and how they became exposed to toxin. After that they can look at attribution -- who did it and to what end.

Today authorities are belatedly pursuing poisoning of the maroon 2009 BMW 320 with plates HD09 WAO listed with 69,000 odometer miles. The door handle theory runs into various problems: why passenger door too? extreme risk to person applying poison? when were binary ingredients combined? sticky liquid or dry powder? rapid breakdown of A-242 [novichok-5] in Salisbury moisture? highly unpredictable dosage? volatilization loss?.

It's completely false that this class of agent is sensitive to oxygen. These chemicals are stable  in air (but they're made and stored as binaries, below). However you can see at a glance from the structures they will break down in seconds if exposed to water (even humidity). That's why the UK is having so much trouble getting macroscopic amounts.

It's complete rubbish to say a non-insecticidal nerve gas is "military grade". Who has ever manufactured 'consumer grade' nerve gases? The confusion here is with artillery shells and cruise missiles, the toxin might be purified to near-homogeneity to save on weight impurities might bring in. Here it makes no sense, bathtub-grade would be equally effective.

What part of b.i.n.a.r.y didn't you understand? Nerve gases are binary weapons: component A stored over here, component B stored over there, transport separately, mix just before use. In the case of novichok-5, both published, both legal, both widely used, both sold by chemical supply houses. The stabilities of A and B in storage also has been taken into account.

On the technical side, it's not been explained how Porton Down is running assays on all the chem swipes. No question, from 1992 on they would have reference samples on hand like the US Army labs concerned with chemical warfare. They would also have antidote in stock to protect their own staff from accidents, to the extent there's anything more effective than atropine and pralidoxime. [However hundreds of distinct compounds in the novichok category were made and explored to various extents.]

Analytic chemistry can certainly be done below the nanogram scale but it's not clear that the UK has recovered agent in milligram amounts (ie have nothing to hand over to the Russians for validation and not enough for isotopes of signature contaminants). What about reagents developed during the Gulf War, maybe immunofluorescence off the fluorine-phosphorus bond? That would have zero background as it does not occur in nature.

My guess though would be a colormetric inhibition assay for the enzyme acetylcholinesterase. A dual spray bottle, one tube with substrate, the other with enzyme and a reactant changing color when in contact with cleavage product. Spray it on the table at Zizzi's or the side of the BMW, see if color production is inhibited. PD would have had this on hand for decades for in-house safety.

The word novichok means newcomer in Russian but in English it is dog whistle code for commies and bring on the lynch mop. There's been zero analytic documentation released on the agent, they won't/can't provide samples while the Russians make jokes about Sherlock Holmes rolling over in his grave -- has the toxin actually been identified at the molecular level or are they just guessing/bluffing/politicizing.

What's up next, wave a little vial of fake WMD have guys in hazmet suits running around on tv to launch another war?

At any rate, I looked into other lethal incapacitants Russians have acknowledged using in the past, notably to resolve the Chechen theatre hostage crisis (84% rescued, 16% dead). The gas piped in was initially said to be 3-methylfentanyl but it was actually a carfentanil and remifentanil mix. [Carfentanil is not a controlled substance in China; it is manufactured legally there and sold over the open Internet, payPal accepted.]

Unsurprisingly, the first witness on the scene, the aerobics instructor -- and probably the police -- assumed the Skirpals had overdosed on street fentanyl. The hospital might even have put them on naloxone instead of pralidoxime. None of that is in the timeline so far.

Chasing down the history of countries like the US and UK who have used chemical weapons themselves either in warfare or assassinations would make for an extremely long post. I do recall  the open air tests of VX nerve gas that the US Army conducted at Dugway, Utah. A faulty nozzle on a warplane carrying a metric ton of agent drifted off onto a Skull Valley farm, killing some 6000 sheep and poisoning the rancher who was standing out in his yard watching birds drop dead out of the sky and jackrabbits keeling over.

I'm not posting novichok chemical structures nor the recommended binaries here since they're well known, all over the internet, in a $25 book at Amazon (free shipping with Prime) plus the Sun newspaper in the UK published a formula a couple days back.

False flag? I've no idea. It's premature to form an opinion so early in the investigation. If the UK knew what happened, the investigation would have been shut down by now. 

Bad for unity on climate change? Absolutely.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: March 15, 2018, 05:18:48 PM »
Here is a synchronized version of the 15 Sept 17 to 14 Mar 18 movies above, plus a standalone of sea ice drift velocities which is convenient for identifying windstorm events.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: March 15, 2018, 03:10:51 PM »
Could the Arctic ice melt out that way rather than predominantly getting eaten away at the edges? Could the ice go like that given sufficient open water to start with at the edges of the Arctic basin? Or is the wind movement fast enough.
Interesting line of thought. While thermodynamics (Arctic amplification of global atmospheric warming) has brought about downward trend lines in volume and area, transitioning to a 'seasonally ice covered' state (as P Wadham puts it) brings in other players such as enhanced ice mobility, peripheral melt geometry and timing, island and basin constraints, and increased intra- and inter-basin export.

In my view, this largely explains enormous timing discrepancy between thermodynamics-focused modeling (2050) and observation-driven Arctic field work (2020). The former approach will prove dead wrong: we could have a late summer blowout at any time.

People here go on about early August 2012 cyclonic winds but CCW stress on the ice primarily disperses it while disfavoring export. The CW circulation in late summer 2007 did both and that year was the real near-miss. Here we are now, eleven years later with the multi-year ice about gone and with it the resilience of thicker ice.

The icepack today responds immediately in proportion to the wind stress distribution, revealing daily translations, rotations, deformations and opening/closing of leads, even at the low resolution of an Ascat image having only 350 pixels wide for a 2000 km Arctic Ocean span.

While it's fairly easy to compare inter-annual deformation, it's fairly hard to take out variability in wind stress and its uneven areal distribution and thus difficult to establish empirical trends in ice plasticity in the continuum mechanics perspective or that of floe caliper sizes, fractures, leads, over-rafting, and ridging in the solid mechanics formulation.

The wind stress has affected the ice very unevenly over the last ten months, leading to very few regions exhibiting coherent net motion. There's been a slight trend to clockwise rotation on periphery but days of motion reversal are a good part of the mix, not to mention the late February over-the-pole narrow swath of deformation that extended from Svalbard to the Chukchi.

It's quite feasible to look at the near-term GFS nullschool wind forecast and accurately anticipate the response of the ice. It's debatable though whether longer term pattern trackers (NAO, AO, PDO, ENSO, MJO, SSW etc) offer any value to anticipating future ice movement.

This coming week, the strong lift-off along the western CAA will continue, with the NW Passage cork west of Banks Island perhaps popping out of the bottle and becoming entrained in the Beaufort stringer of thick floes. The other odd feature is persistent winds carrying ice into the Kara and then west through the Barents. While this disperses the ice and in doing so distorts extent statistics, the main event comes later with melt-out in the already over-heated waters around Svalbard.

As we transition to a melt season forum, it may be helpful to have some time series on hand that cover pre-conditioning from the freeze season. I'll add to these gradually here but update them for melt season as that forum emerges, for 2018 only to keep file sizes lower.

I expect very early development of an open water periphery from melt-out of the Chukchi where the ice never properly formed and the insolation kicks in early. CW circulation will then bring ice from the Beaufort and western CAA into a certain melt zone.

There will also be early and extensive melt along the Svalbard-FJL-SZ line where insolation comes late but already-intruded warm Atlantic Water is the controlling feature. The Kara ice has been disintegrating for weeks and that shed into the Barents will also disappear by mid-spring.

Overall, the central light and dark blues towards the end of the mp4 false-color suggest an outline for the ice that will remain before further wind dispersion is considered. The reds and greens will melt out or be exported.

The rest / Re: Russiagate
« on: March 13, 2018, 05:00:19 AM »
knew the secret formula!  had a very good lab!  stuff seems a degree less trivial than VX, Sarin. weapons grade!!!
Maybe read the above or do a 5 second google search before posting: no secret formulas here, no harder to make than classics, within the abilities of a undergraduate chem major, maybe having access to a fume hood. The main innovations with Novichoks were the binary formulation (neither component is neurotoxic until mixed) plus the components being too common to stop their commerce and movement. Not rocket science, just chemistry.

There is no such thing as weapon-grade in this context, you have conflated this with plutonium, an altogether different realm of physics. These compounds can be 99% contaminant and still be totally lethal with sub-mg exposures. So far nobody has died, even though the UK was very very slow to get on with the atropine. There do exist non-responding Novichoks and others that age badly but perhaps the exposure here was low or another variant was used. 

I would strongly counsel waiting a week to see what further facts emerge before jumping to conclusions based on meagre unverifiable statements from politicians, especially if you have no scientific background whatsoever in the relevant disciplines. There is plenty of time to fashion an appropriate response later if attribution can be unambiguously assigned.

The rest / Re: Russiagate
« on: March 13, 2018, 04:14:56 AM »
Are the structures of Novichok agents known to mortal chemists?
Sure, they were published years ago by the Russian physical chemist who worked there and are readily available on the internet along with the precursor chemicals and (short) synthetic routes need to make them because there's a lot of common ground with insecticides like malathion that also covalently block the active site serine triad conserved in all bilateran acetylcholinesterases. The first sarin-like 'nerve gas' was made by IG Farben and marketed briefly as an insecticide in the late 1930's.

That said, there are a innumerable possibilities for side groups,. It sounds though like Porton Down had a reference sample in stock to allow direct (subsample) spectral comparison. This would make it rare but still known.

Indeed, there's been talk that the polonium-210 that poisoned Alexander Litvinenko was stolen from a Canadian facility, whereas the conventional account has been reprocessed irradiated bismuth product (from Mayak in Ozerskat, Russia) by the Avangard labs in Sarov. No opinion on that.

Attribution in chemistry is also difficult but entirely different. So far the UK has not identified the specific compound within the Novichok group to any specificity. It's not clear whether they recovered stoichiometric amounts of pure residue or just contaminated traces enough for GC-MS. They could maybe look at non-exchanging hydrogen, nitrogen and carbon isotopes or precursor contaminants. The bottom line there could be someone somewhere sometime in the FedEx serviceable world ordered stuff from Aldrich, not terribly helpful since perps might think to do that too.

Countries like the US that run a lot of domestic false flag operations want to see solid scientific attribution. They know the point was to trigger a hot-headed overreaction before the facts are in (if they ever are).

Alexander Litvinenko widow: Theresa May 'did nothing' after my ...
Mrs Litvinenko believes the UK is unable to protect those offered safety, as she urges a fresh look at other suspicious deaths. 14:44, UK, Sunday 11 March 2018. Alexander Litvinenko died after his tea was laced with polonium in 2006. Image: Alexander Litvinenko died after his tea was laced with polonium in 2006. By Greg ...

The rest / Re: Russiagate
« on: March 13, 2018, 03:41:58 AM »
This has false flag written all over it
Whatever it was originally, the UK has certainly captured the narrative and turned it into to a self-serving sob story. They're tripping all over themselves with this story of the local cop no one can verify and his supposed heroic exposure, even as the unscripted passing doctor who administered first aid to the convulsive Yulia suffered no ill effects whatsoever. She could see their symptoms didn't fit a fentanyl-heroin diagnosis: Yulia was airlifted to the hospital while Sergei lay there another hour waiting for an ambulance ride.

A thirteen year sentence for flagrant treason seems like a light sentence in the Russian historical context but there was some value to him in terms of the later spy exchange (which did not seem especially strategic for either side). But what was his priority to the Kremlin in later years when he had long been tapped out and was living openly? There is speculation he had not exactly retired.

Perhaps it is about "sending a message" to other KGB employees who might be thinking of monetizing their inside information. My expectation is that after some more hot air about some soccer game boycott, the news cycle will move on and very little more will emerge.

The rest / Re: Russiagate
« on: March 13, 2018, 03:12:56 AM »
You don't know if they are "experienced organophosphonate chemists"
Actually I do know.

we will soon see where the UK goes with this
Not very far. They're too entangled after years of accepting massive campaign contributions while cheerfully laundering stolen oligarch money through London real estate and lax regulations, while turning their head away from the last 14 similar murders. GCHQ has bugged and logged every known form of human electronic communication for decades so there are no secrets there.

Skirpal's brother, son and wife had previously died young. Endometrial cancer or was it ICR-191 frameshifts? Liver failure in a non-alcoholic 46-year old? The liver's specialty is detox but it can get overwhelmed.

A meaningful response would involve a NATO proxy since the UK has the per capita GDP of Alabama and no allies since Brexit. NATO is just a US front group whereas the US has other agendas with Russia, such as Exxon-Mobil joint drilling projects in the Kara. I don't expect the EU fall on their sword, not heating homes in a warm Arctic, cold Europe without the Russian natural gas flowing isn't plausible.

What sort of response did the UK make after their brilliant young cryptographer at GCHQ was murdered, after a falling out with MI6, with Gelsemium elegans extract and diphenhydramine?

After the dead body of an MI6 spy was found locked in a North Face sports bag in the bathtub of his London flat, police said the death was “probably an accident”. Police found no fingerprints or traces of Williams’ DNA on the rim of the tub, on the bag’s zipper, or on the padlock. The key had been placed under the spy’s decomposing body inside the bag. [It's utterly impossible to remove all clonable traces of DNA of visitors to a flat.]

Williams went missing in August 2010, and the security services failed to notify the police when he didn’t turn up for work. After ten days,, his sister raised the alarm with GCHQ, detectives went to his secret service flat in Pimlico – just over the bridge from MI6’s Vauxhall headquarters – and discovered his body.

It was a warm August day, but the heating had been turned up to full blast inside and “the flat was absolutely baking”, Sutton told BuzzFeed News. “I imagine that was done deliberately to try to accelerate decomposition.” The body was so badly decomposed that it was impossible for pathologists to determine whether Williams had certain poisons in his system when he died, his inquest heard.

Williams’ laptop, mobile phone, and other materials were all laid out neatly on a table in the living room. To Sutton, it appeared that someone had “staged” the crime scene – wiping the flat down to remove DNA and fingerprints, removing incriminating evidence, and leaving out decoy items out for the police to find easily. “It was pretty bloody obvious,” he said. “It was too clean. It was too easy. It was all there on a plate for us.”

Even though Williams had been dead for about 10 days by the time his body was found, no one at GCHQ or MI6 had alerted the police – and even when they realized he was missing, both agencies delayed taking action. Williams’ sister had alerted GCHQ that her brother was missing at around 11.30am, Sutton said, but it was not until around 4.30pm that the spy agencies called the police and requested they visit his flat. “What,” Sutton asked, “went on in those missing five hours?” He told other investigators of his concerns about the crime scene, he said, “but people kind of shrugged their shoulders”.

A high-ranking counter-terror detective who helped oversee the investigation into Williams’ death and asked not to be named told BuzzFeed News that he understood the spy had been working on Russian oligarch financial fraud in his final months, and said his death ranked “at the top end of suspiciousness”.

Mr Karpichkov, 56, who claims to have a source high up in Russian intelligence services, told the Daily Mail a Russian double agent working at GCHQ set his sights on recruiting Mr Williams to work for the SVR, formerly known as the KGB. The GCHQ double agent, known as Orion, befriended Mr Williams and introduced him to a third party named Lukas, according to Mr Karpichkov.

At a Las Vegas hacking conference, Mr Williams' drink was allegedly spiked on a night out with Lukas and he passed out. Photographs were then taken of him in bed next to a man and woman and were used in an attempt to force Mr Williams to cooperate, otherwise his friends and family would see them, says Mr Karpichkov.

But the plot to use the photographs for blackmail was unsuccessful, according to Mr Karpichkov, as Mr Williams told Lukas he would expose Orion as a double agent if they persisted with the threat.

Fearing Orion's role as a mole inside GCHQ would be exposed when Williams returned from leave to MI6 the following day, a plan was hatched to deal with the ‘imminent threat’ posed by Williams.

According to Mr Karpichkov, Lukas returned later that evening to Williams’s flat, bringing a bottle of wine and saying he wanted to apologise for the ‘confusion’ about his earlier visit.

But the wine had been spiked with drugs and shortly after he lost consciousness, he was injected inside the ear with a poison mixed with plant extracts and a chemical called diphenhydramine, a fatal compound which breaks down quickly and is difficult to detect.

Mr Karpichkov served in Russian intelligence for more than a decade, reaching the rank of KGB major where he was privy to Kremlin secrets at the highest level.

The rest / Re: Russiagate
« on: March 12, 2018, 11:35:27 PM »
"White House won't point finger at Russia on poisoning of ex-spy"

I'd be careful where you go with that. The US itself has a long history of assassinations by poison and probably doesn't want Castro brought up again. And let's not forget the weaponized anthrax mailed around by a rogue employee at that Ohio facility. Before lecturing Russia on their sphere of influence, we would first have to disown the Monroe Doctrine.

The UK knows, but hasn't yet disclosed, which of the Novichoks is under discussion - they're a fairly broad class of acetylcholinesterases like the tammelins (sarin, vx etc) -- nor whether it came in with the birthday bouquet or with the 40-minute delay on the rissole.

All of the published structures are easy to make as binaries -- you don't even need a good fume hood -- as the precursors are for sale to anyone from any chemical supply house. Anything in long-term storage can be stolen and sold.

So some sort of false flag operation, not necessary from the adjacent Porton Down chemical warfare unit, might be underway to discredit Putin. Follow-the-money folks have suggested it has to do with stopping the Nord natural gas pipeline. Others note that Skirpal made a whole lot of enemies; his disclosures were very disruptive to Russian national security interests.

Here are some experienced organophosphonate chemists talking about Novichoks at a Science magazine blog ...

I will skip the details but the precursors are in any stockroom of a normal synthetic lab, and it is only two steps to potent organophosphates. And about 4 steps if you want VX, VR or Sarin. The difficult part is to manufacture these agents on a multikilo process scale because of the safety issues, but the chemistry is old and mundane; If you only need a gram of material, with enough time and motivation even a bright undergrad can manage to make these, in the university teaching lab

I don’t think it should be too difficult to avoid accidental poisoning when working with just gram quantity of organophosphate nerve agents – you would use exactly the same technique like when working with atrociously smelly compounds, you would use gloves and thoroughly decontaminate everything before taking it out of the fume hood. Obviously an improvised garage lab would not suffice, and bad working habits would give you something more than just a headache.

Iremember that C&EN article from a decade or two back when James Tour ordered most of the stuff needed to make these toxins from Aldrich and then photographed himself sitting next to enough piles of the stuff to take out an entire country. I wonder if the laws for procurement have changed since then.

But in terms of the Salisbury story, there is something strange. If they were exposed on the park bench to the massive quantities of nerve gas implied, this is consistent with them both immediately collapsing. It’s surprising they have survived (for sarin, time to death after inhalation can be 1-10 minutes and it’s surprising that there wasn’t more collateral damage to the people that treated them and attended at the park bench, from contact/ vapour exposure to residual nerve gas. The week long coma isn’t what you expect from a peripheral effect.
If they were exposed before hand, there are also problems. Slow ons

Instead of VX nerve agent, the Eastern Bloc most common veaponized nerve agent is VR, an isomer of VX. Hence “more rare than VX” at least in the west, but not more difficult to make than VX for one chemist in a normal synthetic lab. My bets would be on VR specifically, because so many Warsaw pact government had it in their arsenals. The stability of VX and VR is excellent, they don’t need a stabiliser unlike Sarin. (The fun part – the manufacture of DIC and DCC coupling agents in the West was made cheap by big orders from military –
because these are the actual stabilizers added to Sarin)

Even Novichok binary is not that hard to make, for a false flag operation or a non-state actor. So it is not a Russian “calling card” like polonium. Careful trace impurity profile analysis and isotope analysis may help to narrow down the source geographically, to the point you can say “this is fully consistent with what we have seen before with material made in Russia” (as opposed to south-east Asia or North America) or “these ethyls look just like being made from corn fermentation-derived ethanol” (as opposed to from ethylene obtained by cracking)et for nerve gases is downright strange. How could they both be exposed hours beforehand, and then both collapse suddenly at the same time ? It’s also that little bit trickier to reconcile with affecting other people.

Oxygen in air has nothing to do with the breakdown of Novichok. Also it looks like there are two classes of Novichok agents. Many of them are moisture sensitive but not dramatically so, they live long enough (persistence time in open environment measured in hours or even days).

Phosgenoxime fluorophosphates is the kind of agents very well suitable for binary (that was reported for weaponized Novichok) and are related to older 90-12 series just as mentioned in the reports. Whereas the phosphoramidine and guanidine class would be more likely the second series described as exceedingly potent if swallowed, fairly water soluble, solid, and some examples of it described as completely water stable.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: March 12, 2018, 09:31:45 PM »
Kane Basin arch took its current form on March 1st.
The arch can also be seen kicking in on Ascat (green arrow) though the resolution is not nearly as clear as in Niall's animation of DMI Greenland. Ice continues to exit the NW Passage (magenta arrow) despite the blockage at Lowther Island (red arrow).

The last week in ice have seen winds induce a lift-off of the ice pack (yellow arrows) from Nares to Bank Island, with its cork to the east popping up twice (orange arrow). The current continues to bring ice in from the west side of upper Nares (orange arrow) whereas the Lincoln Sea quiet zone stays unmoved (purple arrow). About half the new ice from the February storm polynya is exiting the Fram (cyan arrow).

This coming week will see strong winds further deforming the Beaufort stringer to the northwest, accompanied by several days of export out the Bering Strait, to melt oblivion. On the Barents side, there will be considerable ice export through gaps between FJL and the Siberian mainland and continuing strong westward movement of Kara Sea ice south of FJL and Svalbard.

It's fascinating that Arctic ice moves so much every day that changes be can seen even from a low resolution product like Ascat prior to enhancement. Matching Ascat with a Google Earth display, this is tantamount to looking down at the North Pole from a spaceship 10,780 km above the earth, whereas the satellite bearing the scatterometer flies much lower (~837 km) in near-polar orbit.

Note too when the Ascat animations are set to play at 140 ms per day (or one second for a week of data), that week actually occupied 60*60*24*7 = 604800 seconds. (I used much higher time compression in Jakobshavn and Petermann glacier animations.)

Technical note: Google uses the ellipsoid of revolution WGS84 as datum and 'simple cylindrical' (plate carrée) as projection whereas Ascat is in polar stereographic. The OCI-SAf ice motion vectors are over two days; the pair shown are 2018 03 07-09 and 2018 03 09-11 to conceptualize differences; the arrows are 3x actual displacements.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: March 12, 2018, 07:23:44 PM »
In order to be able to forecast the weather and the properties of the sea ice using numerical models, it is crucial that the surface temperature is determined correctly.

Data from satellites is the primary source of information because the Arctic suffers from poor coverage in terms of the conventional observational network, which consists of drifting buoys and a number of land-based stations.

At DMI, the temperature of the surface is not measured directly. Instead, observations are used from three infrared channels on the “Advanced Very High Resolution Radiometer” (AVHRR), which is on board the MetOp-A satellite. The instrument is unable to see through clouds, however. A statistical method is therefore used to provide the missing data. The edge of the ice is shown as a black contour line. It is defined by a sea ice concentration of 15%, i.e. 15% of the surface is covered by ice. This integrated Ice and Sea surface temperature product is part of the EU satellite monitoring program for marine environment, Copernicus CMEMS. The product is based on the OSI-205 product from EUMETSAT Ocean and Sea Ice Satellite Application Facility (EUMETSAT, OSI SAF). The figure shows the latest 36-hour sliding mean temperature of the ice- and ocean surface.

That's right, 2m and 950 mB air temperatures per se are of lesser relevance to winter ice thickening or spring melt ponds than that of the upper ice surface which provides the temperature gradient through the ice (linear at equilibrium in slab heat equation clamped to -1.81ºC bottom water) and so the rate of heat conductance.

Why use observationally unsupported modeled meteorological proxies when you have physical IR temperatures data from satellite where and when they're wanted?

The third image uses ice temperature as an over-tint of Ascat ice roughness/thickness.

The bottom slide show illustrates how ice motion can be tracked via delauney triangulation deformation. Ice transport -- either to intra-basin locales with warmer water (eg Chukchi) or out into the North Atlantic, Barents, Bering or Baffin Bay -- is an important adjunct to in situ thermodynamic melting.

Technical notes: DMI did some nice work here assembling their rolling 36 hour frames from orbital swaths sometimes obscured by weather. The final unsquashed spectral color palette, lost row of date pixels, inability to download animations, omission of scale and lack of ftp server were not the best choices for data dissemination.

The palette fortunately proved to be hue-only HSL, meaning the saturation and luminance channels were empty, allowing recovery of grayscale and re-paletting after RGB decomposition. Ascat needed 106.68% resizing to co-register.

There are huge opportunities for image segmentation (into ice classes) if three independent channels of daily ice imagery can be brought into a single colored animation, as there is different information in each wavelength. Here adding a visible channel is not practical over the Arctic Basin because of persistent clouds. However it may be feasible to add a deformation parameter channel (~viscosity) by analyzing ice motion.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: March 09, 2018, 06:17:46 PM »
Same, synched into one half-sized file

Arctic sea ice / Re: The 2017/2018 freezing season
« on: March 09, 2018, 06:16:43 PM »
Here are 8 views of the late February storm plus wind and thickness forecasts from GFS and ESRL.

Arctic sea ice / Re: Latest PIOMAS update (March update)
« on: March 08, 2018, 06:09:04 PM »
stay with PIOMAS
With such poor grid resolution in the Arctic Ocean proper and mediocre agreement with amended CryoSat, SMOS, Ascat roughness age, snow contributions, ice provenance, icepack motion and commonsense, how is it able to determine these subtle daily and monthly variations to such incredible nominal precision? The trick lies in not posting a netCDF which discourages quantitative comparison, using a virtual averaging volume which is not subject to observational calibration or validation, and getting a free reset on the periphery when the ice is all melted out at the September minimum.

That last dip (in red) was probably due to the storm, I guess.
Right. This was a very unusual event completely attributable to strong persistent winds blowing up the Fram. Despite some nonsense on twitter, it had nothing whatsoever to do with melting ice, föhn winds coming down off Greenland, bizarre warmth at KMJ, upwelling (Kaffeeklub and beyond are far too shallow), or a stable new polynya (it froze over almost immediately as shown by WorldView VIIRS cracking).

There's also been serious confusion about "dynamic" ice thickening of Arctic Ocean ice. Rheological deformation of ice is real enough in thousand-meter thick Greenland and Antarctic ice sheets (eg previous discussions of deviatoric stress tensor invariants as supported by ice-penetrating radargrams) but it's only a useful metaphor for the ice pack in continuum mechanics-based modeling (eg CICE elasto-viscous-plastic deformation intended for fully coupled global climate models).

If you are standing out there on the ice, you won't experience any dynamic thickening. Instead, at the scale of large floes or along the all-important marginal ice zone, solid mechanics fracturing is at work:

Formation of an aggregate scale in Arctic sea ice.
MA Hopkins, S Frankenstein, AS Thorndike
J. Geophys. Res. 109, C01032 (2004).

In this event, the southerly component of North Atlantic deformation was, unsurprisingly, taken up by the Kara tongue intrusion where it was sliced earlier passing around Ushakov Island. Contrary to climate-site tweeters, rifting and ridging flares are easily seen on Ascat despite its resolution -- it may have only 85,000 pixels for the Arctic Ocean proper but they're all grid cells. (Mostly we see heavily interpolated sparse grids; turning interpolation off is a Panoply option.)

Here the issue is a perceptual misunderstanding: a ragged line of contrasting values is reliably recognized (bottom 70º azsimuthal Ascat  bump map contextual animation) even if only one pixel wide for one day of a time series whereas the same number scattered over the image would be seen, if at all, as noise. (Sentinel-1AB confirms this.)

The new ice is currently being compressively squashed against the coast, moving westward along the coast and heading out the door to the south under persistent northern winds associated with this week's meandering weak high. The East Greenland Current works as a rachet: ice leaves with the surface current and doesn't come back.

Here the current was temporarily overwhelmed by an opposing wind as far as drifting surface ice was concerned. However import of previously exported ice from the Fram has proven transitory in the past, under weather patterns of the satellite era.

Where exactly does the East Greenland Current begin to kick in? Ascat and VIIRS time series showed during this event that it's quite a ways farther north than the latitude line connecting Nord Station with Svalbard. On the bottom animation (which pushes very hard on Ascat using transient 32-bit grayscale to mitigate lumping), the dividing line on the newly formed ice shows up clearly: some is going west, the rest is going south.

Fram floe trajectories are very similar to kayaking down a river. At low gradients you have to paddle, be that with or against the wind, because the river pools up and resembles a lake. As the gradient steepens above the head of a rapid, your boat gets caught up in the current and downriver you go, regardless of wind. Except here the wind was strong enough long enough to blow your boat back upriver.

Arctic sea ice / Re: PIOMAS vs CryoSat
« on: March 08, 2018, 04:01:38 PM »
CyroSat-2 does not measure snow depth
CryoSat-2 seeks to determine the freeboard of floating ice. The primary instrument is a synthetic aperture interferometric X-band radar altimeter. Precise altimetry alone has been found not to give accurate ice thickness -- hence the other 31 companion files (such as ice density) in the netCDF under discussion.

These are not taken from generic FYI/MYI climatology, as follows already from the map mismatch with snow depth and density (and good agreement with precip-modeled RASM-ESRL). Here we can benefit from recent papers such as:

Effect of Snow Salinity on CryoSat-2 Arctic First-Year Sea Ice Freeboard Measurements
V Nandan et al

A weekly Arctic sea-ice thickness data record from merged CryoSat-2 and SMOS satellite data
R Ricker et al

Thin Sea Ice, Thick Snow, and Widespread Negative Freeboard Observed During N-ICE2015
A Rösel et al

Note the radar reflection horizon is not necessarily the top surface of the ice nor the top surface of the snow. Locally, there may have been extruded or deposited brine salinity, snow on refrozen rain on snow, or snow melt in the dead of winter from advected semi-tropical moisture and abnormal temperatures.

Whatever, it adds to the mass afloat, though snow (granulated ice) lacks other mechanical, thermal, dynamical and volumetric properties of ice. We are not after freeboard per se but a more nuanced understanding of the heterogeneously distributed composite out there.

The question here is where does this netCDF file get its snow depth, snow depth uncertainty, snow density, snow density uncertainty from and how good are they. It is a near-real time winter product under active development, not a static journal article.

In the meantime, the companion files themselves are instructive even though we don't have a lot of people here who will click on them. The two uncertainty maps are shown below:

Arctic sea ice / Re: PIOMAS vs CryoSat
« on: March 08, 2018, 10:07:04 AM »
Maybe take a look inside that link?

Ankle-deep snow over most of the Arctic sea ice, February 2018 average. Deeper over CAA multi-year ice but nowhere over your boots.

The snow water equivalent follows from the density. (Liquid water is 1000 kg per cubic meter, the numbers here are about a third of that.)

How accurately can snow depth and density be determined from satellites alone? Evidently not that well because California still has people going out on skis to make calibration measurements, even with massive installed snow telemetry (SNOTEL).

What does it mean for Cryosat to measure monthly average ice thickness given that the icepack is in constant motion, with some regions moving much more rapidly than others? February saw displacements of a km per hour on some days.

That is explored in the animation below; the 3rd frame is the Feb 2018 averaged Ascat and the 4th is its posterization. It seems Cryosat is unable to pull together the thick massive floe that originated along the CAA back in October which has now broken into numerous smaller floes making up the long deforming stringer from Banks Island into the northern Chukchi. It does somewhat recognize  the MYI feature that formed back in early July 2017 that has lingered off the Laptev but misses the immense tongue that originated in the Kara in November. Ice thickness is difficult; ice provenance must be brought into the picture.

The netCDF file to use with Panoply to make double-click maps of any Geo2D file (such as snow depth uncertainty):

Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 26, 2018, 11:53:36 PM »
Maybe someone can show sentinels of this CAB scene:
PolarView is well organized, first mouse over your Worldview feature to get accurate lat, lon; then mouse over PolarView to get the right tile, then mouse over the date line to get more dates. The resolution is fabulous. Sentinel-1AB won't go very far back however.

substantial snowcover ...
Why so many mumbo-jumbo posts about snow cover? Some folks are confusing the Northern Hemisphere (half the planet) with the Arctic Ocean (a cold desert seasonally covered with floating ice occupying ten percent of the planet's oceans). Snow on permafrost, NH snow anomaly sites, 2m lake effect snowstorms in Buffalo NY (resp. home town anecdote), Arctic snow pack residuals 6 months from now?

Wrong forum. This is the Arctic sea ice freezing season forum. Neven will start an Arctic melt season forum when that becomes appropriate.

Actual daily data specific to the Arctic Ocean shows ankle-deep snow at best over almost the entire Arctic Ocean today, yesterday, the whole season (graphic below, open source data RASM-ESRL_4UAF_ICE_2018-02-25).

People here have been struggling with that: "Buffalo NY is not even half-way to the pole, it gets tons of snow, the Arctic Ocean is much farther north, it follows the Arctic Ocean has a vastly deeper snow cover than Buffalo NY". It doesn't. It has vastly less.

Ankle-deep is a stand-in for 100 mm (0.1 m, 3.9 inches). Ankle-deep is much less than knee-deep  or waist-deep. Google has pictures for those words if they are unfamiliar. Would you snow-camp in ankle-deep snow, using it for a thermal blanket? It accomplishes nothing to post away here wishing/assuming/claiming the Arctic Ocean snow is deeper. It is not.

That same site has daily radiative energy fluxes, up and down. Numbers for each location. Why share vague feelings about generic clouds and possible snow six month out? Look at their watts/m2 and spare us flux intuiting.

Clouds and snow are highly variable and very complex so can't be intuited, that's why universities have physics depts, that's why we put sampling teams and radiometers out on the ice. Maybe you have an unannounced Nobel Prize in physics? After assimilating flux numbers from the scientific community, sure, post away if you have something better (include a working url and why you think it is better).

Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 26, 2018, 06:15:31 PM »
Here is another perspective on the events leading up the what is unfolding today ... an ice roughness (thickness, age) bump map (vs the emboss above). A nicer version in blue did not survive the rounds of movie codecs so I had to delete it.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 26, 2018, 04:47:51 PM »
Wow ... total blow-out continues at northern end of Greenland (image needs click). Nilas/grease/pancake ice presumably forming on open water, Lincoln Sea reserve continuing to peel back, influx from Bering Sea pushing along the Alaskan coast and remarkable fragmentation overall from compressive stress.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 26, 2018, 02:52:26 PM »
Here is another version of Ascat interferometry, this time with two day separations to get more color from more motion. That is, starting with a week of Ascats, the R,G,B frame is Mon-Wed, Mon-Fri, Mon-Sun. Here I started with 105 Ascats, enough to give the mp4 101 frames.

The second mp4 gives the baseline sequence of 105, no differencing. It has a land mask (attached separately at DevCor) but not one for AMSR2 open water because the Bering Sea weather artifacts have some interest, not so much for the Barents, Fram or Baffin Bay. It's easy enough to make a split open water mask though.

Because we've seen plain ice motion before, a type of bump map on the grayscale values was applied resulting in a hill-shading visual effect. That actually makes some physical sense for Ascat display since its values are the smoother, the blacker. It's also feasible to hang on colors from daily SMOS thickness, MSLP, AMSR2 and so forth.

Technical note: uniquorn has expressed interest in doing up the interferometry on the 8 previous years so the steps are explained one by one at DevCorner. The degree of difficulty here is about 3 on a scale of 10. Dryland is looking at stably scripting the process to make daily or weekly updates during the freezing season, that has some issues.,1259.msg143664.html#msg143664

Developers Corner / Re: Creating Animated GIFs
« on: February 26, 2018, 12:47:07 PM »
slightly more step by step description of this process? I'd like to try to compare this year to previous years.
That'd be a good project. We're look to automate this either in the ImageJ scripting or macro language so daily updates becomes feasible.

This takes more steps than I had remembered. First, a nuisance download as their ftp is broken. After that, mostly ImageJ commands. But try it first with a minimal set of 4 Ascats, eg Mon-Wed, Mon-Fri, Mon-Sun = R,G.B before getting into 109 pixel files.

drag 150 winter days into ImageJ after cleaning file names

convert to grayscale to reduce file size (Image --> Type --> 8-bit)

stack them into a single file (Image --> Stack --> Images to Stack)

crop down to Arctic Ocean region of interest (Image --> Crop)

tile them into a row (Image --> Stack --> Make Montage... label opp with file names)

adjust bulk contrast (Image --> Adjust... --> Brightness/Contrast)

adjust local contrast (Process --> Enhance Local Contrast (CLAHE) set to 63,256,2.20)

duplicate three times, cutting off newest dates (Image --> Duplicate...)

add blank frames at end to make the rows the same length (Image --> Stack --> Add Frame)

combine the three rows into a stack (Image --> Stack --> Tools --> Combine vertically x2 )

so far, 3 rows, 150 columns with each column having 3 grayscale frames that become an rgb frame

subtract the current date row from each of the three date-staggered rows and and add 128 neutral gray to avoid negative color numbers  [Gimp: set layer mode to grain extract, subtract layers pairwise, capture, Colors --> Components --> RGB]

maybe adjust hue and subtract a constant to get rid of some of the neutral gray (Process --> Math --> Subtract ... 50)

slice the rgb back into a stack (Image --> Stack --> Tools --> Montage to Stack ...)

save it out as movie (Plugins --> Input/Ouput --> Save as Movie: 10 fps avi raw excellent)

open .avi in Quicktime, close, convert to .mov to reduce file size

open and covert .mov (or original avi)to mp4

load mp4 to forum

(The land mask is made separately from AMSR2 by selection all 100 of the concentration colors, deleting to transparency, inverting to everything else and filling with black. The land mask is duplicated 150 times and tiled into a layer to go over the day difference layers. I attached an Ascat-ready mask below, just crop it down in parallel to your original cropping of the Ascat stack.)

Here is one with two-day offsets. It has more interferometric color because there is more motion over two days than the one-day offsets used on the freeze forum, plus I drew it out with hue tweaking.

Gimp also does a good bump map to gussy up plain vanilla Ascat motion (no differencing)

Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 25, 2018, 11:42:43 PM »
almost like finding a satellite we didn't know we had! interferometry!
Right, quite a few satellites, like the cloud and soil ones, end up more important after re-purposing. Here NOAA doesn't have the gain set correctly on Ascat's antenna (for our purposes) but rather than hack the satellite itself (unintended consequences? archive continuity?), it is better just to crank up the voltage virtually since since its sequential field-of-view processing has to be re-configured anyway.

There might even have been 10- or 12-bit sensitivity, restricted to ice, in the initial ground transmission (but did they save the data, probably not), the point of all this being a lot better feature tesselation (finite mesh, discrete lattice) results.

OSI-SAF settled on two-day intervals for their sea ice product as more movement takes place so there's less error in measurement of small displacements. I'll post the two-day 'interferometric' product (rgb = n, n-2, n-4) in a bit. These are easy to make but hard to understand.

Right now I'm looking at the one-day, one-degree rotation product (rgbn = 0º, 1º, 2º). That puts the emphasis on zonal (latitudinal) ice motion as opposed to meridional, that is componentize ice motion into coriolis (radial) coordinates. Again, easy to make, though the North Pole is not symmetrically situated; islands and basin move too.

Supposing now we had synchronous rescaled grayscale surface pressure, ice concentration and thinness channels to extend Ascat out to a CMYK, those extra dimensions might put us in position to procede incrementally towards an ice dynamic classifications scheme such as k-means, SVM or PCA/EOF.

The outcome would be specific to winter Arctic ice but not uncorrelated with synoptic-scale weather  -- the North Atlantic Oscillation has really gone haywire this week (,,

Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 25, 2018, 06:39:49 PM »
The movie below shows 'Ascat interferometry' of Arctic sea ice motion over the last hundred days. This amounts to land-masked framen of (R,G.B) = (dayn - dayn-1, dayn - dayn-2, dayn - dayn-3) - (50,50,50)) after contrast renormalization, adaptive histogram equalization and bicubic rescaling. In other words, it's plain gray when and where the ice isn't moving.

During the most recent event, wind up the Fram pushed the icepack over the pole towards the Bering Strait, leaving a wedge along the CAA that widened towards Barrow largely unaffected (bottom animation). This severely deformed ice in the Chukchi; in ice dynamics terminology, the EVP rheology is a lot mushier there (elastic-viscous-plastic: Hunke and Dukowicz 2001).   

EC Hunke, along with two CAA papers, review the 40 years of academic ice deformation physics that goes into CICE:

Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 24, 2018, 08:15:35 PM »
The mp4 below shows the last 100 days of ice moving down Baffin Bay (from the Nares and Parry channels) and down the Fram with the east Greenland current. This is a difficult environment for Ascat with so much of the scene either land, open water and passing weather, so the UH AMSR2 fixed land and daily open water masks are used to cut the image down to just ice (though AMSR itself can have weather issues early in the freeze season).

As this transported ice melts out, it brings cold fresh buoyant water to the North Atlantic and Labrador Sea that is a potential concern for the AMOC. However in recent years none of the ice came from the Beaufort Gyre via TransPolar Drift, not one floe.

In fact this year the Fram ice mostly originated in early November in the Kara and Laptev seas. For that reason, brine exclusion has not preceded very far. Between brine channels within the ice and extruded above to the ice surface, the melt water will have significantly reduced salinity but not be fresh.

As the floes continue to hug the coast until they (or rather their melt) reach the tip of Greenland) the Irminger current has taken matters back up north along the west coast of Greenland and then back south on the other side. We can't monitor this with floe trajectories but in the summer calved bergs from Jakobshavn on reveal directions. Thus there is no support here for the idea that ice from the Arctic Ocean reaches the central North Atlantic overturning zone.

Nares ice is predominantly older thicker MYI but the volume is a tenth or so of the Fram; Parry ice is  less still and mostly FYI formed within the CAA but sometimes includes garlic press MYI ice from the Arctic Ocean. Again, Ascat floe trajectories establish that none of this ice reaching Baffin Bay originated in the Beaufort Gyre during 2017-18, not a single floe. Quite a bit of Baffin Bay ice in the mp4 originates in situ only to melt further south.

Surface ocean currents are effectively the same as surface ice currents according to principal Arctic oceanographer R Woodgate (as ice keels induce them). However most of the water circulates in the Arctic Ocean at a deeper level (~300m) which is not revealed by floe motion nor necessarily parallel to it. Exit volumes along the CAA (125 m western Lancaster), Nares (220 m), Bering Strait (53 m) are somewhat limited by sill heights as only the Fram has a deep sill (2600 m). However these sills primarily impede denser saltier water leaving rather than the more buoyant fresher water nearer the surface. neat poster from 2010 by J Su et al 2013 CAA flows by C Wekerele et al

Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 24, 2018, 05:35:02 PM »
Here are the areas open water NE of Morris Jesup for February. Near an irregular coastline, the 3.125 km UH AMSR2 has significantly better resolution. Most of the sea ice concentration is 100% so colored yellow here to emphasize the intermediate ice. Open water can be color-picked too; here it is replaced here with green, again to it from distinguish intermediate ice.

Ascat doesn't really have this kind of resolution but shows ice movement better. Note the lift-off of the Lincoln Sea ice reserve in the last frame (blue arrow). Given the prevailing winds, this could be the beginning of its demise.

UB SMOS thin ice detects the event fairly well and shows plausible values. However the real nature of the ice here is quite complicated and in rapid flux.

Developers Corner / Re: Creating Animated GIFs
« on: February 24, 2018, 10:57:13 AM »
While waiting for the ESRL archive to build up again, not being convinced products like sea ice thickness are backwards compatible with 2016-17 values, I have been making some cross-silo products.

That is, most of our data source sites specialize in a fairly narrow daily product like bulk ice salinity and stop with that whereas the whole point of netCDF and Panoply is a seamless data integration framework. So this is a good niche for us, where value can be added and floe's automation is needed worse than ever.

The UH SMOS is a good one for cross-silo demo-ing. It has all the ancillary files such as error grid and land mask, some of the products are supplemental to ESRL, and everything is compliant. It is really a nuisance to spew out longer animations manually so floe/panoplyCL will be a big deal just with sites like this.

There is some really excellent coding going on here at They've been very decent about letting me do a lot of online converting of gifs into forum movies. This is mission-critical for us because file size limits what we can do with gif animations from floe. That is, gif is better in the scientific sense with its individual frames but its compression scheme is lousy.

At some point we need to look at remedying site sources that are producing non-compliant or defective netCDFs. Most commonly this involves lat lon associated with but not integrated into gridded data so a 2D but not a Geo2D file shows up in Panoply. This would either harranguing the site hosts or involve drilling into ncgen and re-hosting the archive properly formatted.

I've also come to realize that a lot of plain satellite imagery falls into the defective netCDF category. In effect what they've done is discard the intermediate gridded data and offered a Panoply map in a fixed Arctic projection. The PanoplyCL scaling parameters aren't provided but usually the map is polar stereographic at some multiple of -45º off the Greenwich meridian with a guessable horizon and pole.

For example Ascat is a one-channel 8-bit grayscale in Greenland-down orientation looking down at the north pole with 45ºN as the horizon. It comes without its land or open water masks but those are readily made with UH AMSR2 which though truncated rectangularly attains the same horizon and otherwise matches except for a scale factor.

The Ascat image amounts to a 350 x 300 rectangular pixel array for the Arctic Ocean. It's easy to overlay lat lon polar coordinates and so in effect assign a lat lon to each pixel. So the "inverse netCDF problem" is resolved by stubbing in these Ascat [0,255] numbers for the data values of any master Geo2D file adjusted to this scale. Once the image is in Panoply, it can be reprojected like any other netCDF and integrated with them arithmetically or as partial overlays.

While ESRL provides little or no explanation of what they are doing or why, the post-hiatus archive has gone from REB_plots to REB2_plots for their front-facing gifs, still without providing the underlying netCDF files needed to draw them directly in Panoply.

They did not fix any of the old bugs that I could see, such as different image sizes in the 5-day before and after thicknesses, or crazy complexity in snow contours over ice thickness, or lack of ± explanation of keys.

In their new file names, UAF stands for University of Alaska Fairbanks. They have some very strong comprehensive products for the Bering, Beaufort, Chukchi and ESAS but tend to truncate them arbitrarily at the Canadian border. So it's kinda narrow-minded, omitting say the Barents, but fortunately the region they do cover is critically important. I don't know what the 4 means in 4UAF_ATM and 'atmosphere' for ATM doesn't really describe the air-ice-sea contents of the nc files.

NIC is the military's National Ice Center whose mission is to provide "global to tactical scale ice and snow products, ice forecasting, and environmental intelligence services for the US government". It involves the navy, coast guard and NOAA. Their analysts manually curate sea ice edge products but don't use the same categories as the Canadian Ice Service. I'm not of the opinion that expert annotation is competitive with machine-learning classification over the long haul.

It looks to me like ESRL ditched their previous sea ice thickness basis and reset to the January 2018 CryoSat averaged observational thickness. ESRL will then thicken and compact it from there using their physics model. Ice and snow thickness are by far the most difficult products. Everyone gets a reset to zero at the annual fall maximum of open water that takes in all the peripheral seas and a good bit of the Arctic Ocean but errors still build and build in multi-year ice.   272 MB   2/13/18, 8:05:00 PM   177 MB   2/16/18, 8:29:00 PM
RASM-ESRL_4NIC_2018-02-16.tar.gz   41.5 MB   2/16/18, 8:22:00 PM

Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 23, 2018, 06:24:36 PM »
The mp4 below shows the wind and temperature at the entrance to the Fram over the 23-28 February time frame. The northward surge of warm moist air is not conducive to ice thickening nor export. Ice pack motion will again be 'reverse TransPolar Drift' adding to its net backwardness (and conceptual irrelevance) for the year but turning pole-divergent towards the end of the forecast period.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 23, 2018, 05:26:54 PM »
The images below show export through the CAA to Baffin Bay from Oct 1st to Feb 22nd. It has been surprisingly active for winter. Note a large floe coming down the Austin branch of Byam Martin Channel from the Arctic Ocean has blocked the main Parry Channel from Nov 4th (day 308) on, perhaps backed from an ice jam above small islands west of Lowther below the junction. Parry and Nares "compete' for space in the western bay, with Parry export pushing Nares eastward from Feb 03 (day 034) on. Early clearing of western Lancaster Sound could expedite opening of a Northwest Passage that could lead to loss of thicker coastal Arctic Ocean ice.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 22, 2018, 06:21:02 PM »
low ice concentration maps conformably with the intrusion of saline Pacific water into the Arctic
Right. Below is last two weeks of Ascat sea ice over UH sea ice thinness which is closely related to bulk surface salinity (which is also offered as a UH netCDF Geo2D).

Yes, different. More land fast ice lifting away.
Right, ice is backing out slightly from the Fram and peeling off a bit from Lincoln Sea quiet zone.

PolarView has a very nice Sentinel-1AB swath from the 22nd showing the Lincoln lift-off and condition.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 22, 2018, 04:56:30 PM »
More on the Kara Sea event, another month long drawn-out arch collapse like Nares and Fram, now taking in the last local landfast ice among the islands off the Tamyr Peninsula. Clouds often obscure the view of Suomi NPP VIIRS band 15 night (meaning a lot of days are skipped in the slide show) but it otherwise produces spectacular vistas of the 200,000 sq km affected by the collapse.

The first mp4 compares the perspectives over the last 52 days from AMSR2 UH, OSI-SAF drift, SMOS UB thin ice and Ascat ice roughness. The dates may be somewhat asynchronized as swath timing varies; also the Kara is fairly small relative to resolution, especially for the two-day drift analyses. The ice is a little easier to track in Ascat 2x re-contrasted indexed posterized color, second mp4.

The final image from @zlabe shows a remarkable warm vapor trail from mid-latitude coming up the Fram this weekend and extending up past the north pole.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 21, 2018, 11:31:52 PM »
u r  making the artic sew complicated, y?
Well, it is possible to pass to lower bit depth post-processing (log210=3.22) and colorize if you like old film, sometimes less is more optically. For example, watch the Bering Sea pour across across the Strait and push the mushy Chukchi ice out of its way over the last few days.

Floe motion in the Kara Sea has been quite divergent lately, indicating a weak matrix, but it will all melt out eventually or slip out the Fram but here you might be concerned about it being the 3rd week in February.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 20, 2018, 11:05:29 PM »
This disintegration of the Kara Sea ice cover has been going on for a few weeks beneath the clouds but has really picked up steam in recent days.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: February 20, 2018, 06:51:49 PM »
Wow uniquorn, that is the Image of the Day! Strong and persistent winds are having quite an effect on Kara Sea ice. Seems like it is moving to the north while collapsing from the west ... a lot of action for the 3rd week of February. We can only wish there were not tourism facilities on Vize Island (vz).

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