The 2016/2017 freezing season

[Jim Williams]

Spikes like this happen, but 'here we go again'.  DMI 80N Temp:

I'm waiting for 2:00 PM EST to find out if that 30C really happens.

[magnamentis]

P-maker,

temps spike by 30 Celsius

To me this is quite clear, spike means rapid increase probably before falling again. I don't see that K vs C would help at all. We have words like spike, anomaly and temp to distinguish between well spikes, anomalies and actual temperatures. (Also residual for diff from trend.)

thank you, that's it, my translation of the word "spike" was wrong, at least in this context that's where the confusion came from, now it makes totally sense, i mixed it up with "peak", while a spike can be a peak it doesn't have to be and is distinct, that's where language barriers can play games with non-natives :-)

0 K equals -273.16C as far as i know but as you say, that was not the point.

[Jim Williams]

The main advantage of Kelvin is that temperatures are linear and computing the change in energy is simple math.  101°K is 1% more energy than 100°K.

My knowledge of the temperature group is rather rudimentary and I probably need to move this off to the Stupid Questions, but  is this really true?  I'm having a bit of trouble believing that the distance between freezing and boiling in pure water at standard pressure has any relationship to the percentage change in energy at arbitrary temperatures.

[BenB]

Crandles & ecojosh

First of all, it is not a spike. As is evident from diagrams in the Svalbard thread (such as this: http://www.projects.science.uu.nl/iceclim/aws/files_oper/oper_29102 ) air temperatures have been pretty stable around 2 degrees C for the past five days.

...

Hoping that temperatures in Svalbard may come down again later this winter is fine with me, but before we know that will actually happen, we should be careful putting spikes in the spike...

But the original claim was about the North Pole, not Svalbard. And while temperatures on Svalbard have been (relatively) high for some time, the mild air only reached the North Pole much later, and is likely to stay there shorter. At the North Pole, the temperature certainly spiked, although I don't know whether it was by 30 degrees.

Re. Kelvin and Celsius, and to be slightly pedantic, there is no degree symbol used with Kelvin, and you don't say "280 degrees Kelvin", but rather "280 Kelvin". And Celsius is normally used for freezing degree days.

[Seumas]

is this really true?  I'm having a bit of trouble believing that the distance between freezing and boiling in pure water at standard pressure has any relationship to the percentage change in energy at arbitrary temperatures.

What ktnonine said is correct, but it has nothing to do with the freezing/boiling temperature of water. Converted to Celsius, he just said "-172.15°C is 1% more energy than -173.15°C". It's a bit neater in Kelvin 

The only bit that's incorrect is that it should be 101K, not 101°K, as Kelvin is an absolute scale and therefore not in degrees (c.f. degrees in an angle vs radians)

[ktonine]

The only bit that's incorrect is that it should be 101K, not 101°K, as Kelvin is an absolute scale and therefore not in degrees (c.f. degrees in an angle vs radians)

Aaaaack!  Yes, I am chagrined at the mistake.

Physicist Matt Strassler had a nice post on energy and temperature back in 2014  - Happy (Chilly) New Year

[6roucho]

And Celsius is normally used for freezing degree days.

Surely a freezing degree day is the same regardless of the scale used?

[ktonine]

And Celsius is normally used for freezing degree days.

Surely a freezing degree day is the same regardless of the scale used?

No, since individual temperature units from different scales vary they would not be the same in every scale.  Calculated in °C or K they would be the same, but FDDs in Fahrenheit would be significantly different.  It's no different than miles versus km. 

It's always important to know the definition of the units one is using.

[Rick Aster]

Surely a freezing degree day is the same regardless of the scale used?

If you need to convert degree days, "heating degree day" in Wikipedia has formulas that might be useful: https://en.wikipedia.org/wiki/Heating_degree_day#Conversion

[Jim Williams]

is this really true?  I'm having a bit of trouble believing that the distance between freezing and boiling in pure water at standard pressure has any relationship to the percentage change in energy at arbitrary temperatures.

What ktnonine said is correct, but it has nothing to do with the freezing/boiling temperature of water. Converted to Celsius, he just said "-172.15°C is 1% more energy than -173.15°C". It's a bit neater in Kelvin 

The only bit that's incorrect is that it should be 101K, not 101°K, as Kelvin is an absolute scale and therefore not in degrees (c.f. degrees in an angle vs radians)

OK....Now you can find me over in Stupid Questions...and come prepared with units of measurement.

[Neven]

Yes, go over to the Stupid Questions thread, everyone. 

Or perhaps the Irrelevant Stuff thread, if it exists. 

[jai mitchell]

is it too early to open the melt season thread? 

[Jim Williams]

Yes, go over to the Stupid Questions thread, everyone. 

Or perhaps the Irrelevant Stuff thread, if it exists. 

  Last time I posted Irrelevant Stuff you moved it somewhere. (And it was relevant, even if in Haiku.)

[magnamentis]

Yes, go over to the Stupid Questions thread, everyone. 

Or perhaps the Irrelevant Stuff thread, if it exists. 

is it irrelevant if i don't understand something or understand wrong and ask ?

are common terms when it comes to measurement and other terms that are commonly used irrelevant

sorry but i don't think so but to call it irrelevant from the point of the one who knows/knew is only
keeping others from educating themselves by asking those who know.

i did not mean to derail the thread, i asked one question and it was answered and i thanked for it and for everyone who does not know the difference between a peak and a spike this is relevant to understand what
those who know that difference have to say.

[BenB]

Back to the current season. The southern Baffin/Newfoundland/St. Lawrence zone is forecast to see very high temperatures in just under a week:





Will it be enough to produce noticeable melt in those areas? Of course St. Lawrence hasn't really built up any ice to melt this season...

[Jim Williams]

i did not mean to derail the thread, i asked one question and it was answered and i thanked for it and for everyone who does not know the difference between a peak and a spike this is relevant to understand what
those who know that difference have to say.

It was rather clear to me that what the original post said was misunderstood because many people here are not native speakers of American (English).  What annoyed me was the people assuming the dispute was scientific rather than miscommunication.

However....over in Stupid Questions I am asking a REAL question.  I suspect that is a physical misunderstanding, but I might just not understand how units interrelate.

[Neven]

Here are some loose rules:

1) Every comment in the melting/freezing season threads should pertain to that subject. These are the most popular threads for readers who don't comment, so don't bother them with off-topic stuff.
2) If you have to be off-topic, be short.
3) If you're the third guy who wants to say something about the off-topic subject, say: Okay, guys, this is getting off-topic, let's go to this or that thread - or open a new one - so our discussions don't get lost and we don't bother others. It's a big forum.
4) In other threads you can go off-topic more.
5) Don't start discussions about these rules in the thread itself. PM Neven or go to the The Forum category.

Thank you. End of announcement. Back to the Freezing Season thread. Melting Season thread will soon be re-opened. Allow for some overlap. It's not the end of the world...

Okay, that last sentence perhaps wasn't the best expression to use. 

[Bill Fothergill]

More bad news for sea ice: The UK Met Office has just released its January SST results, and they don't make for comfortable reading. Globally, and in the Northern Hemisphere, it was the second warmest January (behind last year) in the entire dataset. The SH was 4th warmest, with the tropics coming in at a mere 9th warmest.

The global number is bad, but the NH is proportionally worse.
http://www.metoffice.gov.uk/hadobs/hadsst3/data/download.html

At the risk of incurring Neven's wrath for OT stuff, when I was at University - back in the late Cretaceous - we used the term "degrees Celsius" to refer to a temperature, and used "Celsius degrees" to refer to an offset from some other value.

And by the way;

all those wonderful FDD diagrams up-thread could very well do with a K on the vertical axis, since it is meaningless to talk about -1400 C!

If you are referring to ktonine's FDD diagrams, the one that shows negative FDD values is an anomaly chart.

[Gray-Wolf]

Well I never thought a freezing season could be so interesting! Didn't we used to hibernate or something over winter???
Now we are here and realistically punting at final positions for the min due to the changes that we have all witnessed to the 'normal' refreeze season......

We probably have less than 50 days left to claw back some of the deficit we have seen amass over the season before we see temps shoot up into the melt season. We know that a below average forcing melt season was still enough to post a joint second lowest place with 07' ( the first mega melt year) after last winter and this year we have even less volume * so far) and a big drop in FDD's over last year. Just how poor a melt season do we need to see to repeat last years second place?

We have not seen a 'good melt summer' since 07' really with our best being some years managing a few months of high melt but overall no 'joined up' consistent melt over the season? We are around the same stage of the solar cycle as 07' so is this important? Was the dip down into low solar partly responsible for 07's HP dominance that year? Well we're about to find out!!!

[abraca]

Hello,
I've found on https://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn_nowcast_anim30d.gif that once we have lows over pole, the fresh ice is taken from Siberia coastline and compacted into main, thicker pack, while making coastline ice-free or with very thin ice layer, which thickens quickly even on low FDD, it contribute some into volume - the ice seems to be recovering to ~0.5m very fast in these areas. And as main pack gains are not much smaller after such new ice incorporation, it shouldn't amortize the amount of ice gained on these coastlines. This can further make the influence of low FDD on thickness/volume even farther from being linear.
Are you able to estimate how big the effect is and if insignificant or not?

[RoxTheGeologist]

Hello,
I've found on https://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn_nowcast_anim30d.gif that once we have lows over pole, the fresh ice is taken from Siberia coastline and compacted into main, thicker pack, while making coastline ice-free or with very thin ice layer, which thickens quickly even on low FDD, it contribute some into volume - the ice seems to be recovering to ~0.5m very fast in these areas. And as main pack gains are not much smaller after such new ice incorporation, it shouldn't amortize the amount of ice gained on these coastlines. This can further make the influence of low FDD on thickness/volume even farther from being linear.
Are you able to estimate how big the effect is and if insignificant or not?

The Siberian coastline is likely to be one of the last areas where ice forms quickly. It's far to the North, a long way from the Atlantic; both from Atlantic storms and the input of Atlantic waters. It's a shelf, and the surface is freshened every year from river input. It wouldn't surprise me at all if it can act as an ice 'factory' under the right conditions.

[Jim Williams]

Well....it isn't 30C, but it isn't good for the people who'd prefer we didn't effect the climate either.

[Pragma]

The Lebedev formula and chart is something new for me, and I'm not sure I understand it.

If I am reading it correctly, and we take an extreme fall/winter/spring of -30 for 6 months, that would be 6*~30.5*-30= ~5500 freezing degree days. According to the graph, this would mean the ice thickness would not even get to 200 cm.

If this is correct, then after we experience an ice free summer, none of the ice in the next winter will exceed 200 cm, except for the ice that bunches up along the CAA, and general folding or ridging due to winds.

Am I correct or am I missing something?

This surprises me that it is so low, but as a newbie, I just assumed that the 1 metre + ice was formed in a single season near the pole where there was minimum insolation. it really brings into focus how fragile the Arctic ice has become and how vulnerable it will be to the increased energy uptake.

Even so, I have watched very recent climate talks by reputable climate scientists that are still talking about an ice free summer in 2040, right out to 2100. As I said, I'm no expert, but I see this as simply wishful thinking, if not outright fantasy.

[Jim Williams]

Even so, I have watched very recent climate talks by reputable climate scientists that are still talking about an ice free summer in 2040, right out to 2100. As I said, I'm no expert, but I see this as simply wishful thinking, if not outright fantasy.

They are experts....unknown drips under pressure.

The only "scientists" with less authority are Economists -- and for the same reason.  We keep changing the fundamentals on them.

[Pavel]

Hello,
I've found on https://www7320.nrlssc.navy.mil/hycomARC/navo/arcticictn_nowcast_anim30d.gif that once we have lows over pole, the fresh ice is taken from Siberia coastline and compacted into main, thicker pack, while making coastline ice-free or with very thin ice layer, which thickens quickly even on low FDD, it contribute some into volume - the ice seems to be recovering to ~0.5m very fast in these areas. And as main pack gains are not much smaller after such new ice incorporation, it shouldn't amortize the amount of ice gained on these coastlines. This can further make the influence of low FDD on thickness/volume even farther from being linear.
Are you able to estimate how big the effect is and if insignificant or not?

This new ice will melt out completely before august. The last year's Beaufort scenario is possible in Siberia seas. If MYI will not drift to those areas in summer, there will be black open water and additional albedo warming. In case the MYI will drift there, it will be melted there

[CognitiveBias]

The Lebedev formula and chart is something new for me, and I'm not sure I understand it.

If I am reading it correctly, and we take an extreme fall/winter/spring of -30 for 6 months, that would be 6*~30.5*-30= ~5500 freezing degree days. According to the graph, this would mean the ice thickness would not even get to 200 cm.

If this is correct, then after we experience an ice free summer, none of the ice in the next winter will exceed 200 cm, except for the ice that bunches up along the CAA, and general folding or ridging due to winds.

Am I correct or am I missing something?

This surprises me that it is so low, but as a newbie, I just assumed that the 1 metre + ice was formed in a single season near the pole where there was minimum insolation. it really brings into focus how fragile the Arctic ice has become and how vulnerable it will be to the increased energy uptake.

Even so, I have watched very recent climate talks by reputable climate scientists that are still talking about an ice free summer in 2040, right out to 2100. As I said, I'm no expert, but I see this as simply wishful thinking, if not outright fantasy.

I get 246cm, almost 2.5 meters.  Perhaps a unit conversion error to go with all the temperature issues today?

[Neven]

I would like to draw your attention to this comparison map that shows the difference between PIOMAS and CryoSat-2 for January:



The map was made by forum member Michael, and he explains the how in the PIOMAS vs CryoSat-2 thread.

[Pragma]

Thank you CB.

Doh!!!, nothing more than a brain fart! {sheepish grin}.

The scale is in cm, not mm, and my brain interpreted 200 cm as .2 metres (What's an order of magnitude between friends?)

In my defence, things did seem odd to me, but I still say the imminent loss of summer ice is much more likely than 2040.

The age of fake news indeed. 

[Bill Fothergill]

The Lebedev formula and chart is something new for me, and I'm not sure I understand it.

If I am reading it correctly, and we take an extreme fall/winter/spring of -30 for 6 months, that would be 6*~30.5*-30= ~5500 freezing degree days. According to the graph, this would mean the ice thickness would not even get to 200 cm.

If this is correct, then after we experience an ice free summer, none of the ice in the next winter will exceed 200 cm, except for the ice that bunches up along the CAA, and general folding or ridging due to winds.

Am I correct or am I missing something?

I make it ~ 196 cms under the conditions you describe - as long as your "-30" means 30 degrees below the freezing point of brine. In other words approx -31.8 deg C. (However, I note that Cognitive Bias gets a different value, so, after I've finished some chores the wife has lined up for me, I will re-check the maths.)

If you genuinely mean a temperature of -30 deg C, then that is 28.2 degrees below the freezing point of the sea water. That gives an FDD value of ~ 5166, which, using the Lebedev transform, equates to ~ 189 cms.

You might want to check out this description from the NSIDC...
https://nsidc.org/cryosphere/seaice/processes/thermodynamic_growth.html

Once you've read that, be sure to also click on the "Cycle" tab. Of particular significance is the final paragraph, of which I have highlighted the sentences most germane to your question...

"Remember that ice grows because of a transfer of heat from the relatively warm ocean to the cold air above. Also remember that ice insulates the ocean from the atmosphere and inhibits this heat transfer. The amount of insulation depends on the thickness of the ice; thicker ice allows less heat transfer. If the ice becomes thick enough that no heat from the ocean can be conducted through the ice, then ice stops growing. This is called the thermodynamic equilibrium thickness. It may take several years of growth and melt for ice to reach the equilibrium thickness. In the Arctic, the thermodynamic equilibrium thickness of sea ice is approximately 3 meters (9 feet). However, dynamics can yield sea ice thicknesses of 10 meters (30 feet) or more. Equilibrium thickness of sea ice is much lower in Antarctica, typically ranging from 1 to 2 meters (3 to 6 feet)."

[Pragma]

Thank you Bill, that fleshes things out nicely.

This gives the FDD charts much more meaning. The obvious shift in the anomaly is striking in itself, but I can now comfortably relate it to ice development and thickness (or lack thereof)

As for Arctic ice reaching equilibrium, perhaps that will soon be a historical reference.

[aslan]

Buoy near the North Pole hitting again (bis repetita non placent...) 0°C:

http://www.infoclimat.fr/mer/bouees.php?id=26565&jour=20170210

http://www.infoclimat.fr/mer/bouees.php?id=26566&jour=20170210

And Svalbard is on overheating mode. It has been since the early hours of the 5th that the airport is above freezing. The monthly record is still not reached (7°C in 2012) but this is the second worst thawing period for any winter month here, second only to the begining of January 2016. Before 2016, more than two or three day above 0°C in a row was unheard of in Svalbard in winter.

[Neven]

And not just an arm of warm temps reaching towards the North Pole, but a whole bulge:

[seaicesailor]

And not just an arm of warm temps reaching towards the North Pole, but a whole bulge:

One of the few occasions that the actual conditions have turned out even warmer than forecasted.
A lot of cold coming to the whole Arctic next week but the forecasts differ a lot beyond 5 days. The undecipherable SSW stuff disrupting the NH atmosphere??

[Tigertown]

The problem next week, I am afraid, will be un-tethered Fram export. The front and everything nearby is so loosened up now, it should flow much smoother, once the wind changes back in about 36 hours. Volume will most likely take another hit from what has already happened. When more thickening and freezing starts will it be able to gain ground on export, before the next warm intrusion or storm, or combo?

Export kicks in good on the 13th
CLICK IMAGE PLEASE

[Bill Fothergill]

The problem next week, I am afraid, will be un-tethered Fram export...

Perhaps the term "fast ice" will need to be redefined?

[Kratje]

And not just an arm of warm temps reaching towards the North Pole, but a whole bulge:

Hi, I hardly ever comment. This could even be my first post. I'm checking in every day though.

In this image -10C is still green and therefore it seems a lot worse than it is.

[aslan]

And not just an arm of warm temps reaching towards the North Pole, but a whole bulge:

One of the few occasions that the actual conditions have turned out even warmer than forecasted.
A lot of cold coming to the whole Arctic next week but the forecasts differ a lot beyond 5 days. The undecipherable SSW stuff disrupting the NH atmosphere??

The "SSW" was actually quite weak and barely qualifies as a SSW. I am really reluctant to call this thing a SSW, it was looking way way more like a minor displacement event. The polar vortex was never disrupted (a major displacement event means that the polar vortex is torn apart and shred in small pieces). And average 10 hPa zonal wind at 60°N barely touch the zero threshold. Arctic oscillation is taking a hit but the negative AO signal is weak. And the NAO is even positive, and not heading toward sub zero values. Which is quite frankly not unexpected, weak displacement event can lead to an increase frequency of storms over Atlantic. What is surprising is the magnitude of the decoupling between NAO and AO. I don't know why NAO is able to remain in neutral / positive territory will AO is negative. This said consequences from this displacement event will probably not be long lasting and are probably not the main cause of the disturbance we are seeing in the models.

The real game changer will be the next SSW - probably a true one, a SSW in the definition, this time-. Polar vortex is going to take a severe hit, and an early SFW out of this is not out of question. In the meantime, MJO is coming back to life with a (very, very) very strong 7 - 8 phase. Among others things (for example, boosting the incumbent El Niño...), strong MJO signal will also probably help the positive PNA pattern and in the end but a more prominent factor in the weaking of the positive NAO. There is even what can be qualified as an ongoing tectonic shift in the tropics with the Walker cells being strongly affected by the MJO (such a signal in the tropics was not seen since November) and taking a bit of en El Niño look.

In the 5 - 10 days window, the cold and high pressure foretasted for Arctic are probably a reliable signal, but without putting too much emphasize on this. It will not be a long-lasting nor a strong signal. After 10 days, the real game comes with the disruption of the polar vortex and the building effects of strong tropical convection.

And looking forward, Mach should be really interesting. An early SFW seems likely; and going on with the shift in the tropical convection, this could have profound effects for the beginning of the Spring -hoping a cold and snowy March for Europe ^^ -.

The 10 hPa winds viewed by GFS at 348h:



The current state of the tropical convection:



And the forecasted one :

[Ice Shieldz]

A point of clarity on asian's most excellent and informative post - SFW stands for Stratospheric Final Warming.

Wow, i can see how if we do get hit with this early and strong of an SFW, that it could be a final devastating blow to what remains of freezing season, along with hastening melt season. Especially given any continuation or amplification of our arctic-intruding cyclone trend - which seems likely given the exogenous forcings and teleconnections asian mentions.

[Tigertown]

The problem next week, I am afraid, will be un-tethered Fram export...

Perhaps the term "fast ice" will need to be redefined?

If you have a piece of machinery that you want to work more efficiently, what do you do? Round off the corner. Having these big pieces of land fast ice gone, should have the same effect.

[Tigertown]

Extent is possibly about to go up, depending on how much was lost on the Atlantic side today. If the SIE goes up, it's likely because of Bering Strait export.(See Below) The problem is that volume, concentration, and area are all down, which gives an extent increase a different meaning.

[Tigertown]

I'm pretty sure A-Team would have something better about right now to show the effects of the latest weather, but I did the best I could with this. Again, this doesn't hurt that much now, but when things get to moving, we will have to see.

[jdallen]

And not just an arm of warm temps reaching towards the North Pole, but a whole bulge:

One of the few occasions that the actual conditions have turned out even warmer than forecasted.
A lot of cold coming to the whole Arctic next week but the forecasts differ a lot beyond 5 days. The undecipherable SSW stuff disrupting the NH atmosphere??

Yah, this is a LOT more powerful surge than I was first looking at 4 days ago.  That was bad *enough*.

[romett1]

Climate Reanalyzer shows nice eye forming just south of Svalbard next Saturday. Winds 110 -130 km/h and pressure 944. Not too friendly for ice edge.

[oren]

And not just an arm of warm temps reaching towards the North Pole, but a whole bulge:

Hi, I hardly ever comment. This could even be my first post. I'm checking in every day though.

In this image -10C is still green and therefore it seems a lot worse than it is.

Welcome Kratje. Feel free to post more, the first post is the hardest...

[Steven]

... a temperature of -30 deg C, then that is 28.2 degrees below the freezing point of the sea water. That gives an FDD value of ~ 5166, which, using the Lebedev transform, equates to ~ 189 cms.

Actually, Lebedev's formula uses freezing degree days relative to 0°C (rather than -1.8°C).  This is discussed in more detail in Bilello's paper, which gives a nice overview of this topic.  Here is the relevant quote:



http://arctic.journalhosting.ucalgary.ca/arctic/index.php/arctic/article/viewFile/3658/3633

[subgeometer]

Climate Reanalyzer shows nice eye forming just south of Svalbard next Saturday. Winds 110 -130 km/h and pressure 944. Not too friendly for ice edge.

That looks ugly, and just where it can stir up the warmest waters. Before that Bering Strait and sea is looking at 3 days of over 60k winds blowing out the strait from about 84hrs in, Which can only thin the ice out more and there are already areas of sub 0.5m ice in the Beaufort and ESS according to Bremen SMOS

[Bill Fothergill]

... a temperature of -30 deg C, then that is 28.2 degrees below the freezing point of the sea water. That gives an FDD value of ~ 5166, which, using the Lebedev transform, equates to ~ 189 cms.

Actually, Lebedev's formula uses freezing degree days relative to 0°C (rather than -1.8°C).  This is discussed in more detail in Bilello's paper, which gives a nice overview of this topic.  Here is the relevant quote:

Steven, I was simply paraphrasing what appears on the NSIDC website...

"The freezing temperature of ocean (saline) water is typically -1.8 degrees Celsius (28.7 degrees Fahrenheit). If the average daily temperature was -5.8 degrees Celsius (21.6 degrees Fahrenheit), this would be -4 degrees Celsius (24.8 degrees Fahrenheit) for one day, as the following equation shows:

[-1.8] - [-5.8] = 4 degrees below freezing"
https://nsidc.org/cryosphere/seaice/processes/thermodynamic_growth.html

One of these two sources is clearly in error, so you might want to drop a quick note to the NSIDC helpdesk. In any dealings I have had with them, the helpdesk staff have been invariably helpful. (Email: nsidc@nsidc.org)

By the way, there is an obvious error in the quote from the NSIDC that I just provided - the bit that says... " this would be -4 degrees Celsius (24.8 degrees Fahrenheit)".

About 6 years ago, I pointed out that they were getting some Celsius/Fahrenheit conversions wrong. The problem was that, in a C to F conversion, they were slavishly applying the "multiply by 1.8 then add 32" rule. That, of course, only holds for temperatures, not for temperature differences. Instead of 24.8 FDD (Fahrenheit), it should have said 7.2 FDD (Fahrenheit). I thought that little problem had all been corrected. However, perhaps a bit was missed - or perhaps the error was re-introduced by someone who doesn't understand the technique.

{NB I would do the contact myself, but I'm already engaged in a dialogue on a different matter, so I don't want to introduce any distractions into that email interchange. I would however be very interested in learning if/when you get a definitive clarification}

[Steven]

One of these two sources is clearly in error, so you might want to drop a quick note to the NSIDC helpdesk
... I would however be very interested in learning if/when you get a definitive clarification

I just emailed NSIDC, and will let you know if they reply.

It seems impossible to find the original Lebedev paper:  it is a very old paper, in some Soviet/Russian journal.  But the discussion in Bilello's paper is unambiguous:  he is very careful in his paper to distinguish between -1.8°C and 0°C.  At most places he uses -1.8°C,  but at the moment that he discusses the Lebedev formula, he explicitly uses 0°C  (repeatedly, so it's unlikely to be a typo).

Anyway, it may be of interest to note that Bilello mentions yet another empirical formula for sea ice thickness in terms of freezing degree days, attributed to Zubov's (1945) observations in Kara and Chukchi Sea.  That Zubov formula can be expressed as

h ≈ (625 + 8 * FDD)^0.5 - 25

where h = sea ice thickness in centimeters.  For example, if the Freezing Degree Days FDD = 4000, then this formula gives h = 156 cm.

[Cate]

Canadian Ice Service analysis for east coast: fairly solid coverage at the moment along the Labrador Coast to NE Newfoundland waters with concentrations up to 100%. Mostly thin first-year ice with some grey and grey-white on the front. All looks pretty normal here for this time of year, but in another couple months we'll be praying for sou'westerlies. 

http://iceweb1.cis.ec.gc.ca/Prod/page2.xhtml?CanID=11091&lang=en&title=East+Coast

[Lord M Vader]

Colder weather looks likely during the next couple of days as we are getting closer to the final freezing month. In fact, from CCI_Reanalyzer one can see that the forecast for 7 days ahead calls for temperatures BELOW the 1979-2000 average(!) When was the last time THAT happened in the Arctic?  Well, from DMI it happened by February 2015...

Aside of potentially colder weather (which would be very well needed for the sea ice) there are signs of a weather pattern favorable for decent export through both the Atlantic and the Pacific exits.