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numerobis

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Re: The 2017/2018 freezing season
« Reply #350 on: November 19, 2017, 06:58:54 PM »
Look at those isobars. Extremely windy these next days in the Central Arctic

We're looking at winds 70 km/h gusting to 90 km/h tomorrow morning in Iqaluit, and ECMWF suggests it's going to get worse Monday night into Tuesday morning. Iqaluit is, by local standards, isolated from the worst winds: Kimmirut and the communities in Nunavik and Kivaliq will be getting the brunt of the storm.

Temperatures started climbing last night. They should hit above freezing on Tuesday, when we expect rain. We were just getting into some good ski conditions, too.

The inlet is frozen enough for a polar bear to walk on (one was spotted this morning). At the edge of the inlet, a fuel tanker is filling up our tanks (we thought the one two weeks ago would be the last, but no, there was one more). On Thursday it stopped just past the edge of the ice; by yesterday it was encased in grey ice.

Shared Humanity

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Re: The 2017/2018 freezing season
« Reply #351 on: November 19, 2017, 10:41:40 PM »
A general warming trend over the last 4 decades.

Looks more to me like the continents are flat while the oceans are warming -- though the Pacific is more variable than the Atlantic.

Are we looking at the same charts?

Since 2002, the colder years for both Siberia and North America are more like the warmer years from the previous century.

Siberia:

1991 to 2000: 5 of 10 years with temps below -11C.
2001 to 2016: 1 of 16 year with temps below -11C.

1991 to 2000: 3 of 10 years with temps higher than -10C.
2001 to 2016: 13 of 16 years with temps higher than -10C.
« Last Edit: November 19, 2017, 11:02:56 PM by Shared Humanity »

Brigantine

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Re: The 2017/2018 freezing season
« Reply #352 on: November 20, 2017, 12:46:49 AM »
Freshwater storage in the Arctic Ocean has increased. Compared with the 1980–2000 average, the volume of freshwater in the upper layer of the Arctic Ocean has increased by 8,000 cubic kilometers
Do you know if that includes freshwater *ice*?

It's on the same scale as the ~10,000km^3 decrease in sea ice, so is the *liquid* freshwater up 8,000 or ~17,000?
(and so the total liquid+ice fresh water down ~1,000 or up 8,000 GT)

A-Team

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Re: The 2017/2018 freezing season
« Reply #353 on: November 20, 2017, 03:42:43 PM »
Do you know if that includes *freshwater* ice?
There's a comprehensive and quite readable discussion of every aspect of Arctic freshwater in Chapter 7 of the assessment. By freshwater, oceanographers don't mean drinking water fresh, merely how not-as-saline as 34.8 psu seawater. So 34.7 psu is already freshened by how much water would have to evaporate to bring it up to 34.8 psu. The surface freshwater anomaly extends down a few tens of meters at most (first image).

First year ice is still quite salty -- not single ice crystals per se which are standard ice Ih with no inclusions -- but from extruded salt in brine channels that's still around. Thus the Russian 'Barneo' expedition this year had to melt snow to get their drinking water. By some accounts, a 2:3 mix of salt:fresh is utilizable by humans.

Below, some scattered snippets from Chapter 7. The attached figures are better viewed in the original.

Snow, Water, Ice and Permafrost in the Arctic (SWIPA) 2017
Arctic Monitoring and Assessment Program (AMAP), Oslo, 2017 [cutoff date mid-2016]
http://www.amap.no/documents/download/2987

The Arctic water cycle is expected to continue to intensify during this century. Mean precipitation and daily precipitation extremes will increase over mid- and high latitudes, with implications for the management of water resources, flow of freshwater into the Arctic Ocean, changes in sea ice temperature, and amplification of regional warming (through reduced surface reflectivity caused by a shift from snow to more rain in the warmer seasons).
 
The areal reduction of old sea ice has consequences for mean sea-ice thickness, thickness distribution, and surface roughness of Arctic sea ice (Hansen et al., 2014; Renner et al., 2014; Landy et al., 2015). Reduced ice thickness is related to changes in the forcings, whereas changes in thickness distribution are directly related to the properties of the different ice classes present.

Younger sea ice has on average higher salinity than older ice, and this has various consequences, for example how much freshwater is transported with drifting ice and on habitat conditions for organisms living within the ice.

A shift from perennial sea ice to predominantly seasonal ice types will cause changes in the physical properties of the ice cover. These changes are mainly associated with the volume of brine trapped within the ice. In contrast to first-year ice, multi- year ice has undergone a summer melt season and in the process lost most of the brine trapped within.

The brine volume, which can be calculated as a function of salinity and temperature, determines the porosity of the ice, which controls many important properties of sea ice, such as its strength, thermal and dielectric properties, mass (chemical and gas) transport, and the development of melt ponds and surface albedo.

Salt and heat fluxes are affected by the increased presence of first-year sea ice. First-year ice growth rates are higher than for older ice types, which means more salt is released during autumn and winter ice growth. In summer, the higher melt rates for first- year ice increases freshwater input to the surface ocean, thereby increasing buoyancy flux and stratification. Gas exchange rates through sea ice are also changing: more saline ice means more active exchange processes because gas permeability is higher in more porous sea ice.

In contrast to the southern hemisphere, the configuration of continents in the northern hemisphere is such that they effectively capture moisture from the atmospheric storm tracks of the Westerlies and redirect in north-flowing drainage basins disproportionate quantities of freshwater into the Mediterranean configuration of the Arctic Ocean (Figure 7.1).

Hence, while the Arctic Ocean represents only 1% (in terms of volume) and 3% (in terms of surface area) of the global ocean, it collects over 11% of the global river discharge (Dai and Trenberth, 2002; Carmack et al. 2016). e Trade Winds also transport moisture from the Atlantic Ocean across the Isthmus of Panama to freshen the Pacific Ocean, and some of this freshened water eventually flows into the Arctic Ocean through Bering Strait. e resulting salt stratification or halocline (i.e. a freshened upper ocean and salinity increasing with depth) is the dominant characteristic of high-latitude seas in general and the Arctic Ocean in particular .

The freshwater budget of the Arctic Ocean is governed by the system’s key functions and processes: the delivery of fresh and low-salinity waters to the Arctic Ocean by river inflow, net precipitation, distillation during the freeze/thaw cycle and Pacific Ocean inflows;

The Arctic Ocean freshwater budget was recently updated by Haine et al. (2015) (Table 7.1). The distribution of freshwater within the Arctic Ocean is heterogeneous and controlled by circulation and water mass structure. The Arctic Ocean is made integral to the global ocean by the northern hemisphere thermohaline circulation which drives Pacific Water through Bering Strait into Canada Basin, and counter-flowing Atlantic Water through Fram Strait and across the Barents Sea into Nansen Basin.

Following Bluhm et al. (2015), it is useful to recognize four vertically-stacked circulation layers (Figure 7.5): (1) the wind- driven surface layer circulation that is characterized by the cyclonic Trans-Polar Dri from Siberia to Fram Strait and the anticyclonic Beaufort Gyre in southern Canada Basin; (2) the underlying circulation of waters that comprise the halocline complex, composed largely of Pacific Water and Atlantic Water that are modified during their passage over the Bering/ Chukchi and Barents/Siberian shelves, respectively; (3) the topographically-trapped Arctic Circumpolar Boundary Current that carries Atlantic Water cyclonically around the boundaries of the entire suite of basins; and (4) the very slow exchange of Arctic Ocean Deep Waters.

Within the basin domain two water mass assemblies are observed, the difference between them being the absence or presence of Pacific Water sandwiched between Arctic Surface Waters above and the Atlantic Water complex below; the boundary between these domains forms the Atlantic/Pacific halocline front.
 
But the distribution of freshwater within the Arctic Ocean is not uniform, and salinities range from about 35 where Atlantic Water enters the basin to near zero adjacent to river mouths and along the coast (Carmack et al., 2016). is huge range in salinity, the main parameter that determines density stratification in high-latitude oceans, affects almost every aspect of circulation and mixing within the Arctic Ocean.

Relative to a reference salinity of 34.8, about 101,000 km3 of freshwater are stored in the Arctic Ocean (this is an estimate of the 2000–2010 annual average volume by Haine et al., 2015; Table 7.1). The largest freshwater reservoir exists in the Amerasian Basin, specifically in the Beaufort Gyre where about 23,500 km3 freshwater are stored and the accumulated freshwater anomaly diluting the upper ocean above the 34.8 isohaline surface is about 20 m thick. In the Eurasian Basin, typical liquid freshwater thicknesses are 5–10 m.

Freshwater in the solid phase as sea ice is another important reservoir in the Arctic. About 14,300 km3 of freshwater are stored in sea ice (2000–2010 average from Haine et al., 2015). e largest sea ice volumes are north of the Canadian Arctic Archipelago and Greenland and across the pole, where the ice is still relatively thick (Kwok et al., 2009).

The seasonal freeze-thaw cycle acts to exchange freshwater between the liquid and solid phases. Its amplitude is about 13,400 km3 (averaged over the decade of the 2000s; Haine et al., 2015), close to the annual average freshwater volume stored in sea ice. Sea-ice formation in winter occurs throughout the Arctic Ocean but the prevailing currents tend to export ice frozen over the Eurasian shelves toward the central Arctic and the Trans-Polar Drift (Figure 7.5).

Under current climate conditions only about 35% of the sea ice present at the end of winter, when the ice volume peaks survives the summer to become multiyear ice. Of the remaining 65%, most melts within the Arctic although some is exported south.

Kwok and Rothrock (2009) reported submarine and satellite data that show the average end-of-melt season ice thickness was 3.02 m in 1958–1976 but just 1.43 m in 2003–2007. Because both ice extent and ice thickness are declining, sea-ice volume is also declining.

Currently, the Arctic Ocean is freshening (Haine et al., 2015), warming (Polyakov et al., 2012), losing sea ice (Stroeve et al., 2012), and its ice cover is changing properties and moving faster (Kwok et al., 2013).
« Last Edit: November 21, 2017, 11:18:35 PM by A-Team »

Brigantine

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Re: The 2017/2018 freezing season
« Reply #354 on: November 20, 2017, 10:57:46 PM »
Table 7.1
Resevoir / 1980-2000 / 2000-2010 / Change (km^3)
Liquid FW / 93,000 / 101,000 / +8,000
Sea ice / 17,800 / 14,300 / -3,500
Total FW / 110,800 / 115,300 / +4,500

So in fewer words: No.

But I also didn't realize that the 8,000 km^3 figure is only up to the 2010's, not 2017. So the reduction in sea ice volume is comparatively less significant than I thought anyway.

Niall Dollard

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Re: The 2017/2018 freezing season
« Reply #355 on: November 21, 2017, 10:04:36 PM »
Some warm air moving up Baffin at the moment (as Numerobis mentioned already) spreads further north over the next couple of days. Especially so at the upper level. By Friday the models are showing a pool of very warm air settled over the northwest of Ellesmere. Often one of the coldest spots in the northern hemisphere.

The ECMWF model is showing upper air temps above zero at 850 hPa (circa 1500m) level. Likely though to be more like -10 C to -15 C at the surface.

A second surge of upper warmth is progged to spread up over Greenland in about a weeks time, especially up the eastern side (although this is further out and maybe not as reliable - given current volatility in the models)
« Last Edit: November 21, 2017, 10:12:42 PM by Niall Dollard »

Adam Ash

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Re: The 2017/2018 freezing season
« Reply #356 on: November 22, 2017, 03:11:37 AM »
Would not warm air at 1500 metres lead to a significant increase in downward radiation and hence warming near surface?

Presumably the warm air lens at 1500 metres is in the form of an inversion layer, which would further trap warmth beneath, or at least slow outward radiation from the ice/ocean surface??

Brigantine

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Re: The 2017/2018 freezing season
« Reply #357 on: November 22, 2017, 08:07:33 AM »
This very orderly pattern is not the one I was expecting to see... It almost looks like one giant rigid turntable, pivoting right on the pole.

Is this common?
« Last Edit: November 22, 2017, 08:37:16 AM by Brigantine »

Niall Dollard

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Re: The 2017/2018 freezing season
« Reply #358 on: November 22, 2017, 08:07:48 AM »
Temperature inversions are a very common feature in the high Arctic especially in the long winter period of no sun, Information on inversion trends at Eureka are shown here:

http://aolab.phys.dal.ca/publications/ao2010.pdf

This report by Bradley states that temperature inversions as large as 35 C are possible. These cases involve warm anomalous southerly airflows in mid winter. It is possible to get temperatures aloft exceeding 0 C. For several days in Jan 1977 temperatures over Alert, Resolute and Eureka all exceeded 0 C reaching +4.6 C at 1.2 km above Alert on Jan 12th when the surface temp was -15 C.

So I suppose in terms of climatology, upper air temps over 0C in winter, does happen from time to time.

www.geo.umass.edu/faculty/bradley/bradley1992d.pdf

numerobis

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Re: The 2017/2018 freezing season
« Reply #359 on: November 22, 2017, 03:28:50 PM »
Some warm air moving up Baffin at the moment (as Numerobis mentioned already) spreads further north over the next couple of days.

+3 C yesterday and rain in Iqaluit. Pretty much massacred our snow.

Interesting tidbit: it appears that CYFB can't actually record wind speeds above 100 km/h (above 40 kt it starts to go wonky). I wonder what other weather details are wrong around the Arctic.

litesong

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Re: The 2017/2018 freezing season
« Reply #360 on: November 23, 2017, 02:25:10 AM »
The High Arctic average temperature (named, Present High Arctic Berserker ;D(2), PHAB ;D(2) or FAB ;D(2) has been over average temperature for 90+ days.  So far, FAB ;D(2) has continued to exist, despite two cold fronts edging into the High Arctic, one cold front, at times, all over Canada(even Arctic Canadian islands) & one over much of Northwestern Siberia.
« Last Edit: November 25, 2017, 01:47:11 AM by litesong »

A-Team

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Re: The 2017/2018 freezing season
« Reply #361 on: November 23, 2017, 06:26:37 PM »
@Zlabe has a nice graphic on temperature anomalies the last couple of months, consistent with persistent open water in the Chukchi and north Svalbard (where both air and water are too warm).

The animation butts an ESRL prediction to Nov 22nd (with inset AMSR2 observational) onto an ESRL forecast to Nov 29th. The agreement of observation with forecast is so-so by its end (flashed red 22), though there are issues with fairly comparing hours and defining ice boundaries. Note that ESRL resets midway through (using some variation of AMSR2), ie it starts knowing the open boundary, goes out until its prediction ends, then gets a new observed boundary and goes out on its second round of forecast.

Overall it seems ESRL forecasts are overshooting on freeze-over; if so the Chukchi will be considerably more open than shown on Nov 29th.
« Last Edit: November 24, 2017, 10:28:46 AM by A-Team »

meddoc

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Re: The 2017/2018 freezing season
« Reply #362 on: November 24, 2017, 11:17:12 AM »
I guess these pretty much tell the Story

JayW

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Re: The 2017/2018 freezing season
« Reply #363 on: November 24, 2017, 11:46:57 AM »
Look at those isobars. Extremely windy these next days in the Central Arctic, very cold in Siberia, not really in the Atlantic sidem

I can't really add much, except a new resource. (Unless someone has already posted these which I didn't see)

  I'm not really a fan of Ryan Maue, but he left weatherbell and is working with a new site called WeatherDotUS.  It has more ECMWF data, all freely accessible in 6 hour increments.

For the deterministic ECMWF, it has an Arctic view and these parameters. 

MSLP
10m winds. (first attachment)
850mb wind
300mb winds
850mb temp anomaly
500mb height anomaly
Total precipitation
Precipitable water venues
Modeled snowfall
2m temp anomalies


http://wx.graphics/models/ecmwf/ecmwf.php


And they also have the ECMWF 51 member ensemble system, with 6 hour increments, and out to 360 hours (although, forecasts at such lead times have questionable value)

Unfortunately, no arctic how however.

Parameters are

500mb height anomaly.
500mb height normalized anomaly
850mb temp anomaly
2m temp anomaly  (second attachment)
MSLP anomaly
Precipitation


http://wx.graphics/models/ecmwf/eps.php
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A-Team

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Re: The 2017/2018 freezing season
« Reply #364 on: November 24, 2017, 03:13:14 PM »
Here is the bottom line so far for all this weather on the Bering Strait side of the pole, shown as a subtractive comparison of the last 30 days for the years 2013-2017. (The key year 2012 will not be available at UH AMSR2 for six more weeks.)

Blue: open water in both years
Yellow: open water in 2017 only
Red: open water in other year only

In the lower left corner, 2016 has more open water than 2017 on the Oct 25th initial date but as the 2017 re-freeze slows, it overtakes 2016 by Nov 23rd end date (ie more yellow than red).
« Last Edit: November 24, 2017, 03:19:11 PM by A-Team »

Niall Dollard

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Re: The 2017/2018 freezing season
« Reply #365 on: November 24, 2017, 06:37:44 PM »

I can't really add much, except a new resource. (Unless someone has already posted these which I didn't see)

  I'm not really a fan of Ryan Maue, but he left weatherbell and is working with a new site called WeatherDotUS.


I mentioned Weather.Us alright at post #243 in this thread. I think Neven had some difficulty adding the cloudiness chart to the ASIG page.


It has more ECMWF data, all freely accessible in 6 hour increments.

For the deterministic ECMWF, it has an Arctic view and these parameters. 

MSLP
10m winds. (first attachment)
850mb wind
300mb winds
850mb temp anomaly
500mb height anomaly
Total precipitation
Precipitable water venues
Modeled snowfall
2m temp anomalies


http://wx.graphics/models/ecmwf/ecmwf.php



I hadn't seen those versions before, Thanks.  :)

Edit: I've just seen I have become an ASIF Citizen !  :)

litesong

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Re: The 2017/2018 freezing season
« Reply #366 on: November 25, 2017, 01:41:30 AM »
@Zlabe has a nice graphic on temperature anomalies the last couple of months, consistent with persistent open water in the Chukchi and north Svalbard (where both air and water are too warm).
Ah, as stated above your post.... the Present High Arctic Berserker ;D(2), PHAB ;D(2) or FAB ;D(2):
The High Arctic average temperature (named, Present High Arctic Berserker ;D(2), PHAB ;D(2) or FAB ;D(2)) has been over average temperature for 90+ days.  So far, FAB ;D(2) has continued to exist, despite two cold fronts edging into the High Arctic, one cold front, at times, all over Canada(even Arctic Canadian islands) & one over much of Northwestern Siberia.
///////
The FAB ;D(2) is now 95+ days in length, of which I predicted in its pre-60 days, that it could reach 100 days in length.
« Last Edit: November 25, 2017, 01:50:56 AM by litesong »

Neven

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Re: The 2017/2018 freezing season
« Reply #367 on: November 25, 2017, 09:23:39 PM »
Edit: I've just seen I have become an ASIF Citizen !  :)

Congratulations, Niall.  :)

Present High Arctic Berserker ;D(2), PHAB ;D(2) or FAB ;D(2)) has been over average temperature for 90+ days.

Here I was, thinking we had enough acronyms by now.  ;)

The FAB ;D(2) is now 95+ days in length, of which I predicted in its pre-60 days, that it could reach 100 days in length.

How does that compare to the past decade?
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litesong

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Re: The 2017/2018 freezing season
« Reply #368 on: November 26, 2017, 03:51:40 AM »
 Using the JAXA High Arctic temperature line graph, I started the Present High Arctic Berserker (FAB ;D) in defiance on an anti-AGW webcyst(no misspelling). One of the deniers, who I knew on another anti-AGW webcyst, made fun of my use of Berserker, started posting dramatic paintings of Viking-like warriors & gods battling in snows & ices, calling them them Ice Berserkers.
To answer your question, long High Arctic continuous over-temperatures, during the late 1950's & early 60's were ~ 30 to 40 days. Over decades, these continuous over-temperatures very slowly increased their periods. I started paying attention to them when the over-temperatures got to 80days. Then, one of the FAB ;D 's got to one hundred days. But, it didn't stop there. One went for 140 days. In latter 2016, everyone paid attention when one FAB ;D (what I named FAB ;D(1) ) jumped to ~ 20degC over the average" temperature line. Of course, the 20degC over-temperature was quick up & down, & people quieted down, the lower the temp went. However, FAB ;D(1) went from latter 2016, deep into 2017, for over 230 days. That's one of the reasons I thought, once FAB ;D(2) got to 55-58 days in length, it had a good chance to get to  100 days (of which it is very close now). I can't say if FAB ;D(2) will get as long as FAB ;D(1), but it could if the continuing cold fronts over Canada & northwestern Siberia don't push hard into the High Arctic. Also, FAB ;D(2) started earlier than FAB ;D(1), so we'll see how long FAB ;D(2) can last.
It is no coincidence that these Present High Arctic Berserkers (FAB ;D) occur in the High Arctic during the sun periods, very low on, but mostly below the horizon.
« Last Edit: November 26, 2017, 04:09:31 AM by litesong »

Neven

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Re: The 2017/2018 freezing season
« Reply #369 on: November 26, 2017, 10:29:02 AM »
JAXA High Arctic temperature line graph

I'm sorry, but which graph is that?

Do you have any graphs that summarize what you just explained in words? Or the exact dates of those above average excursions? Personally, I find a measure like FDD (freezing degree days, see here) more useful than just the period of time a trend line spends above the baseline.
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Re: The 2017/2018 freezing season
« Reply #370 on: November 26, 2017, 01:50:17 PM »
Personally, I find a measure like FDD more useful than just the period of time a trend line spends above the baseline.

Here's "Snow White's" visualisation of the DMI data.

I've been meaning to produce an "improved" version on "her" behalf for months now, but what with one thing and another that's still going to take a little while longer:

https://www.linkedin.com/search/results/content/?keywords=%23SaMDES
 
« Last Edit: November 26, 2017, 01:55:49 PM by Jim Hunt »
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litesong

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Re: The 2017/2018 freezing season
« Reply #371 on: November 26, 2017, 02:47:54 PM »
I'm sorry that I said JAXA. It is the Danish Meteorological Institute data above the 80th parallel. Yes, you are correct that FDD is more useful(& accurate) to calculate High Arctic conditions. But, I'm mesmerized by the powerful rise of the High Arctic temperatures, that even "weather low  temperatures" over nearly 4 million square kilometers can be lifted ABOVE the average temperature line CONTINUOUSLY for nearly two thirds of a year.
 & all this High Arctic heat is occurring while the solar TSI has been languid for many decades & low for 11 years(including a 3+ year period setting a 100 year low TSI record). Wouldn't the low TSI affect the FDDs?
Maybe, I can support my post above, with some dates. Anyhow, thank you for questioning me.   

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Re: The 2017/2018 freezing season
« Reply #372 on: November 26, 2017, 02:55:02 PM »
It is the Danish Meteorological Institute data above the 80th parallel.

It would be helpful if you could include links to and/or pretty pictures of the data you are referring to. Is this the one?



If you need some help in how to get the right picture in the right place in your post please do not hesitate to ask. The image above is linked to the DMI web site, so it will change as the days go by.
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A-Team

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Re: The 2017/2018 freezing season
« Reply #373 on: November 26, 2017, 03:42:51 PM »
It would be helpful if you would stop using emoticon-reserved text combinations in your unexplained acronyms to unlinked data. If you need some help in how to shut them off in your posts please do not hesitate to ask.

Note there are far better temperature anomaly resources than 80ºN. That does not cover -- nor serve as valid proxy for -- large areas of the Arctic Ocean which are of critical importance this time of year to the refreezing season as well as for regional ice thickening that drives the coming melt season.

In other words, given DMI 80ºN, it is impossible to infer what is going on in the Beaufort - Chukchi - ESAS area. The Arctic Ocean is not at all symmetric about the North Pole, nor is the weather. Yes, there will be a meagre R value (correlation coefficient) but the real ocean-wide data is only a click away.

DMI 80ºN has convenience as a long term record and so for displaying daily departure from trends. It's been used since forever on these forums and people here are skilled in its interpretation. However DMI 80ºN statistics have lost most of their value in the 'new Arctic' which requires a much shorter baseline to properly define unusual warmth.

Graphs lose geo-referencing. They are a relic from the past when journals charged mightily for colored maps, but not so much for line graphs with spot color. Today we have the internet and complex 2D color is free so we use maps. Journals still do not allow gif animations, 1989 standards pose their next challenge.

Using a spherical cap condenses local data to a point, ie treats it as isotropic. This is a bad idea because air and sea temperatures are strongly anisotropic near the 80ºN latitude line, primarily because of the line of islands, the nearby continental shelf break, and the bathymetry driven route of warm incoming Atlantic Waters. Thus it is not the right tool for tracking the freeze or melt seasons. For the Svalbard - SZ line, it would be far better to use a 'trapezoidal' temperature proxy of a few latitudinal degrees bounded by edge longitudes that excluded the western Fram.

The areas last to freeze are the first to melt. The seasonality of open water extent we are so exercised with expands northward from them. It is very unusual for the ice pack to have persistent and substantial internal polynyas like the one this year; at 3 km resolution, the ice pack almost always appears 'simply connected' in topological terms. Open leads are an important exception but require Sentinel-1AB resolution and massive display size.

We have not done much here with the temperature that effectively matters,Teff. This is the temperature at the ice/snow interface that is relevant to the 1D heat conduction equation through the ice to freezing the water below (or for melt pond purposes).

We should have a hundred-page forum on the heat equation but for some reason don't; it has exact solutions for many special cases of interest (including sinusoidal seasonality), not just Arctic ice, so it's well within skill sets here. For example, geothermal heat maps under Antarctica ... how do you get from observable Curie depth to the bottom of the ice: use the heat eqtn. Ditto Greenland, ESAS methane risk and so on. It's buried inside every model of ice.

https://blogs.agu.org/geospace/2017/11/13/new-antarctic-heat-map-reveals-sub-ice-hotspots/

The effective temperature is directly observed by various satellites and available daily in various netCDF files linked in earlier posts. People here generally have stronger backgrounds in meteorology and so are drawn to the two meter temperature T2m which again is convenient but only a so-so unnecessary proxy to physically relevant conditions.
« Last Edit: November 26, 2017, 05:08:29 PM by A-Team »

litesong

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Re: The 2017/2018 freezing season
« Reply #374 on: November 26, 2017, 04:06:04 PM »
It is the Danish Meteorological Institute data above the 80th parallel.

It would be helpful if you could include links to and/or pretty pictures of the data you are referring to. Is this the one?



If you need some help in how to get the right picture in the right place in your post please do not hesitate to ask. The image above is linked to the DMI web site, so it will change as the days go by.
Yes, that is the one, plus all the charts going back to 1958.

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Re: The 2017/2018 freezing season
« Reply #375 on: November 26, 2017, 06:35:19 PM »
I hate emoticons. They reduce emotion to poor caricature. "Shall I compare thee to an ... emoticon ?"
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numerobis

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Re: The 2017/2018 freezing season
« Reply #376 on: November 26, 2017, 07:29:55 PM »
According to the ice atlas:
n Frobisher Bay, new ice formation has begun as early as mid October, and as late as the second week of November.

https://www.canada.ca/en/environment-climate-change/services/ice-forecasts-observations/publications/sea-climatic-atlas-northern-waters-1981-2010/chapter-2.html

There’s been ice in the tidal flats since the first week of November. Ice started to spread onto deeper water in the second week of November, but the storm last week wiped it out. Just as well: we just got a dump of snow, which would have insulated the ice quite effectively.

A-Team

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Re: The 2017/2018 freezing season
« Reply #377 on: November 27, 2017, 08:47:45 AM »
Here are a couple of animations of SMOS ice thickness from Oct 10th to Nov 25th. The first shows (rather low) daily thicknesses in meters and second local thickness changes from one day to the next. UH SMOS is Cryosat-aware though this set of files may not fully reflect that calibration. The widening ring of thickening ice can be seen as well as hesitant Fram export.

The 3rd animation of bulk salinity shows the progress of brine exclusion in newly forming ice. Note the ice between Svalbard and Severnaya Zemlya has not consolidated yet. The compound palette resolves similar salinities better; it is done on the tiled frames within gimp with the hue-saturation tool localized to green.
« Last Edit: November 27, 2017, 09:58:36 AM by A-Team »

seaice.de

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Re: The 2017/2018 freezing season
« Reply #378 on: November 27, 2017, 03:24:04 PM »
A-Team, thanks for the always excellent visualization of the SMOS data!

Just a comment: the data comes with an uncertainty estimate which is unfortunately not symmetric and large for relatively thick ice. To use the data in a reasonable way is with a data assimilation system which can handle such uncertainties. For example, the Copernicus Arctic Marine Forecast System now assimilates the SMOS sea ice thickness. You can download the forecast products from the Copernicus website (select Arctic Ocean Physics Analysis and Forecast):

http://marine.copernicus.eu/services-portfolio/access-to-products/

litesong

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Re: The 2017/2018 freezing season
« Reply #379 on: November 27, 2017, 05:17:56 PM »
To answer your question, long High Arctic continuous over-temperatures, during the late 1950's & early 60's were ~ 30 to 40 days. Over decades, these continuous over-temperatures very slowly increased their periods. I started paying attention to them when the over-temperatures got to 80days. Then, one of the FAB ;D 's got to one hundred days. But, it didn't stop there. One went for 140 days. In latter 2016, everyone paid attention when one FAB ;D (what I named FAB ;D(1) ) jumped to ~ 20degC over the average" temperature line. Of course, the 20degC over-temperature was quick up & down, & people quieted down, the lower the temp went. However, FAB ;D(1) went from latter 2016, deep into 2017, for over 230 days. That's one of the reasons I thought, once FAB ;D(2) got to 55-58 days in length, it had a good chance to get to  100 days (of which it is very close now). I can't say if FAB ;D(2) will get as long as FAB ;D(1), but it could if the continuing cold fronts over Canada & northwestern Siberia don't push hard into the High Arctic. Also, FAB ;D(2) started earlier than FAB ;D(1), so we'll see how long FAB ;D(2) can last.
It is no coincidence that these Present High Arctic Berserkers (FAB ;D) occur in the High Arctic during the sun periods, very low on, but mostly below the horizon.
I agree with Neven, that FDD data are the best way to scientifically determine High Arctic changes. But, on the AGW denier liar whiner webcysts that I oppose such, I am having real-time fun presenting the ever lengthening days of existence of continuous High Arctic over-temperatures. I show their rapid rises & falls & as surmised from the above, during low sun & sun below horizon seasons, the low falls are increasingly ABOVE the average temperature lines, established since 1958. Here is one of my posts, open to your enjoyment or critique:
litesong wrote:
litesong wrote:....FAB ;D(2) has now risen to 10degC over recorded average for the 4 million square kilometer-sized High Arctic & appears to be ~ 95 days in length. A High Arctic warm front has enveloped on the North Pole & High Arctic, with enough heat remaining to interact with the "continuing Canadian cold front" & thrusting the most northerly part of the cold front to the south. The solid cold front has been on Canada for a month (more?). But, the powerful warm front is showing it has more... "solidity".
....FAB ;D(2) has now risen to 10+degC over recorded average for the 4 million square kilometer-sized High Arctic & appears to be ~ 95+ days in length. However, the northern portion of the long term Canadian cold front may re-establish itself over the Canadian archipelago. Plus, the cold front over Northwestern Siberia is extending itself south deep into China.
FAB ;D(2) has dropped to 8degC over average temperature for the High Arctic. FAB ;D(2) appears to be very close to 100 days of existence, which was my prediction ~ 40+ days ago.... much like my posts, nurse-maiding FAB ;D(1) to its record breaking 230+ days of existence from latter 2016 to deep into 2017.
It appears FAB ;D(2) may continue well past 100 days of existence. Strong warm fronts are developing & will envelope Greenland & Canadian Arctic Archipelago & appear to pump heat into the High Arctic. These warm fronts continue to suppress  the long term cold front over Canada, to the south. The continuing north Siberian cold front is bordered by higher latitude warm fronts, both in eastern & western Siberia.
//////
Don't worry. I won't post too often, taking away from the better science you posters present. But I wanted you to know that some oppose the AGW deniers in other ways too.   
« Last Edit: November 27, 2017, 06:23:33 PM by litesong »

A-Team

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Re: The 2017/2018 freezing season
« Reply #380 on: November 27, 2017, 08:28:34 PM »
Seaice.de, thanks for the link and recommendation. I will take a look at that resource shortly.

However it requires an exceedingly tedious and privacy-invasive registration survey -- your phone and street address etc etc are obligatory -- and at the end the captcha test-text and 'submit' button were both broken; all data even samples was blocked and broken as well. I sent a message to the service desk but that too was a complex, poorly defined form.

Simple but adequate internet forms were perfected 20 years ago, why put up new beta code at this late date? In summary we don't have time to go all over the internet doing this mickey mouse at a hundred different portals; people here will not use the product regardless of merit.

Same thing happened at Copernicus last year with Sentinel: the portal outsourced to aerospace contractor subsidiaries. Finally someone just mirrored all the data up at Amazon so people could get some work done.

Meanwhile, the animation below looks at Fram export since the Sep 10th minimum as well as the Atlantic Waters shelf line. The left half (reversed) shows 78 days from 2016 compared to the same dates from 2017 on the right half. The inset shows UB SMOS thin ice ocean-wide for the same date range. (Their ftp server is slower than a dial-up!)

The sea ice at 100% concentration (according to the 6.25 km UH AMSR2) is shown as pale green with dark green edges to bring out features in Fram export (to the extent there are any) to help visualize floe motion. There's still ambiguity because ice can form de novo, plus aggregate and disperse, within the Fram itself. However export appears to have picked up in November.

Note wipneus regularly reports on export volume on the Piomas forum; a long-range visualization of ice age class export has been posted up-forum numerous times though a fall 2017 update is not currently available.

The issue is apparent persistent cessation of both Beaufort Gyre circulation and Fram export that has accompanied months of mundane weather. It's wait-and-see whether this is a new feature of the New Arctic or just a passing system variability.
« Last Edit: November 28, 2017, 09:32:33 AM by A-Team »

FishOutofWater

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Re: The 2017/2018 freezing season
« Reply #381 on: November 27, 2017, 11:47:31 PM »
The may be convection going on near the edge of the Chukchi sea shelf edge and Barrow canyon. There has been so much open water in the Beaufort and Chukchi seas this fall that salty Pacific waters may have been flowing into the Arctic through the Bering strait. The fresh water of the Beaufort gyre is being mixed into at the 300 m level. At the 100m level the fresh water lens has moved towards the Mackenzie delta and the main channel of the CAA. Increased amounts of fresh water may have moved through the CAA as export out the Fram declined.

I'm not sure it's happening but this may be the first time since humans have been looking at it that Pacific heat has been advected into the Arctic through the Bering strait. In previous years the heat was all lost to the atmosphere. Heat in the Beaufort and Chukchi was from "summer water" that stored heat as it sank below the icy surface layer in the early fall.

The blocking high over the Aleutians for the past 30 days has been stunningly powerful and has advected huge amounts of atmospheric heat into the Chukchi and Beaufort seas. It also may have increased the flow of Pacific water into the Arctic ocean.

FishOutofWater

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Re: The 2017/2018 freezing season
« Reply #382 on: November 28, 2017, 12:11:41 AM »
There's a very strong sea surface height gradient through the Bering sea towards Barrow canyon. this strong SSH gradient is coupled with a strong northwards current. Compare 2016 with 2017 SSH gradients through the Bering strait.

Susan Anderson

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Re: The 2017/2018 freezing season
« Reply #383 on: November 28, 2017, 12:31:27 AM »
Fishoutofwater, thank you. That's something I've observed and wondered about this year, as so many big storms have traveled north from the equator this year. Thanks for the clarity.

FishOutofWater

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Re: The 2017/2018 freezing season
« Reply #384 on: November 28, 2017, 01:21:08 AM »
Susan, please understand that much of what I wrote is based on interpretation of assimilation model based information on the web. Oceanographers will write research reports on what's happening that you will read about in a year or two. Their reports will be reliable. I'm trained in science but this is not my specialization. Remember that I'm a semi-retired geochemist, not an oceanographer.

meddoc

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Re: The 2017/2018 freezing season
« Reply #385 on: November 28, 2017, 09:18:39 AM »
The Vortex seems to have split into 3 Cores, something I haven't seen before.
The Bering still will see a continued Heat Influx, thanks to this rare Configuration.
I wonder if we get to see a Quadruple Core System in this not- so- Freezing Season.

A-Team

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Re: The 2017/2018 freezing season
« Reply #386 on: November 28, 2017, 12:55:09 PM »
Very nice, Fish. I had not seen the Mercator Ocean site before. It is an interesting approach to a portal; a lot of neat features there, some of which work a lot better than others. There is no explanation of how products are developed so their accuracy isn't known.

Still, it's great to have the oceanography supplemental to RASM-ESRL. For example the '100m' products (which are actually 92m), provide a nice bathymetry mask for Siberian continental shelf.

The images appear created with Panoply but more likely just use some of the same javascript libraries.. The Geo2D netCDF files are not provided. Access to underlying data png archives is forbidden (interdit) so actually capturing a product involves a lot of manual stepping through screens, though those direct urls can be hacked as explained below allowing ImageJ to import a long png series using 'List to Stack', which creates in effect the unsupported ftp client to their html server.

For the Arctic, MercOcean provides the 18 products below plus a 7 day forecast.  The calendar goes back to 01 Aug 16 but for Arctic surface water temperature anomaly, the return is 'image not generated yet' (désolé, l'image n'a pas encore générée, merci de réessayer plus tard).

The depths are slightly different from those advertised; numbers don't pencil out in meters, feet or fathoms. Perhaps they are still using pre-Revolutionary units of pied du roi, pouce or toise.

To make an animation, start with the link below, make a date range in a spreadsheet, paste on the product type, save as .txt file, sit back and enjoy a croissant and let ImageJ do the rest. This will entirely strip out the site into forum animations in about twenty minutes. (Not the other 17 maps though; the section view called Labrador is also of some interest to us.)

header that receives png types, note double date change needed:
http://static-bulletin.mercator-ocean.fr/img//psy4qv3r1/20171127/arc/psy4qv3r1_20171127_arc_

For everyone's convenience, the attached .txt file provides the links for all 18 from the 10 Sep 17 minimum up until the 27th of November. [work in progress, fixes underway: there's some screw-up at MercOcean involving mis-indexed pngs.] This will generate the same for 2016 with a quick substitution.

sea_surface_height_0m.png
sea_ice_thickness_0m.png
ice_velocity_0m.png
ice_concentration_0m.png
current_0m.png

anom_temperature_0m.png

temperature_0m.png
temperature_34m.png
temperature_92m.png
temperature_318m.png
temperature_1062m.png
temperature_2865m.png

salinity_0m.png
salinity_34m.png
salinity_92m.png
salinity_318m.png
salinity_1062m.png
salinity_2865m.png

http://bulletin.mercator-ocean.fr/en/PSY4#2/62.6/-85.1

Mercator Ocean is a privately-owned non-profit company. It provides a service of general interest to France and Europe as a whole. The organization was founded and is funded by the five major French institutions involved in operational oceanography: CNRS, Ifremer, IRD, Météo-France and SHOM.
« Last Edit: December 02, 2017, 11:50:47 AM by A-Team »

A-Team

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Re: The 2017/2018 freezing season
« Reply #387 on: November 28, 2017, 11:18:21 PM »
In support of the analysis Fish is doing above, here are sea temperatures for Nov 2017 at the various depths provided by MercOcean. Oceanography moves a LOT slower than weather but heat content advected from the Bering Sea or Barents/Fram can be massive relative to air and strongly affect both the timing of freeze-over as well as winter thickness development.
« Last Edit: December 02, 2017, 11:58:43 AM by A-Team »

A-Team

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Re: The 2017/2018 freezing season
« Reply #388 on: November 28, 2017, 11:33:11 PM »
Same as above, but synched into one image to allow easier comparison of activity at the four depths and also shown as reflected depth pairs at regions of special interest such as the Bering Strait and Svalbard/Barents where 0m water temperature (ie at the surface) is compared to that at 32m depth.

The latter region shows subsurface Atlantic Waters having more dramatic changes over the 25 days shown of November 2017; 34m depth is displayed reflected over 0m surface temperatures in the 3rd animation.
« Last Edit: December 02, 2017, 12:01:39 PM by A-Team »

numerobis

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Re: The 2017/2018 freezing season
« Reply #389 on: November 29, 2017, 04:37:32 AM »
So many storms in South Baffin this year. City services have been suspended ten times already since September.

Each storm brings up a lot of heat with it.

Rain storms heat up the frozen land, and snow storms insulate it. There’s not much sea ice to cover down here.

bbr2314

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Re: The 2017/2018 freezing season
« Reply #390 on: November 29, 2017, 08:13:06 AM »
Hudson Bay's refreeze over the last week has been one of the earliest on record over the past twenty years it seems. Should be mostly frozen by 12/5-12/10!

A-Team

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Re: The 2017/2018 freezing season
« Reply #391 on: November 29, 2017, 03:20:09 PM »
So many storms in South Baffin this year.
Mercator Ocean offers an interesting depth section of water temperature and salinity from Labrador to Greenland. One hopes there is a mooring or two that provides actual data to anchor modeling.

The animation below shows upper salinity over temperature for November, finishing with a forecast out to 08 Dec 17. Salinity at lower depth hardly changes over this timeframe so I dropped the bottom in favor of enforcing synchronicity with the temperature profile time series. The temperature warms markedly with depth even as we go into winter.

Looking at their separate current vs depth map for the North Atlantic, this does not represent a northbound warm water intrusion from a branch of the Gulf stream but rather southbound from the Hudson Bay(?). They show speed ok in color but indicate direction with too-tiny arrows, a common parameter setting omission in Panoply-like tools.

There's a second cross section of interest to us (not analyzed here, called OVIDE CLIVAR 25) that cuts through the AMOC cold spot and Irminger Current below the tip of Greenland. I might write to ask if they can offer sections for the Bering Strait and Fram regions.

I would encourage people to use this site which complements RASM-ESRL. They are likely reprocessing netCDF files stored behind the onerous registration wall of Copernicus which asks that you disable spyware security on your computer to access data files.

http://bulletin.mercator-ocean.fr/en/PSY4#3/72.82/-51.33

Technical note: the very weird implementation of png graphics format is causing a lot of problems for MercOcean. It may have something to do with enabling png animations in html 5 but those are currently quite lame and could be done within gif89. It seems each file is using a different lookup table, probably based on color abundances. Their pngs load as indexed color so unless you immediately convert to RGB, subsequent time series layers will use the LUT of the first image which is wholly inappropriate for them. The horizontal white line in both the temperature and salinity charts is probably a NaN artifact in the underlying data as Panoply-like javascript would not introduce this otherwise.
« Last Edit: December 02, 2017, 11:53:43 AM by A-Team »

Shared Humanity

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Re: The 2017/2018 freezing season
« Reply #392 on: November 30, 2017, 05:47:43 AM »
Hudson Bay's refreeze over the last week has been one of the earliest on record over the past twenty years it seems. Should be mostly frozen by 12/5-12/10!

It is freezing much faster than 2016 but pretty much in line with 2012 through 2015.

SimonF92

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Re: The 2017/2018 freezing season
« Reply #393 on: November 30, 2017, 09:47:19 AM »
Hello to all,

I generally like to "lurk" on this forum, there are several experts from whom I have learned a great deal over the last few years.

Firstly to the people who take the time to collate data and figures for the rest of us to learn from, I would like to thank you for your continued efforts in doing so.

I generally visit this forum, DMI temps, cci-reanalyser and NSIDC's website at somepoint most days. Today I noticed that cci-reanalyser has updated their service to provide several new visual data sets on the condition of the arctic (and world). Significant new additions are their Snow Depth figures and 500hPA Geopot. Height.

http://cci-reanalyzer.org/wx/DailySummary/#snowd-mslp

Many thanks again

Simon


meddoc

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Re: The 2017/2018 freezing season
« Reply #394 on: November 30, 2017, 10:40:15 AM »
The Polar Vortex looks to get tossed around the next few Days, again.
The Result will be a Donut- shaped elongated 2- Core System (Scaninavia & Siberia) spreading over Greenland, CSE- Europe into Siberia & the Far East. Leaving Alaska, the Bering Side exposed.

Neven

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Re: The 2017/2018 freezing season
« Reply #395 on: November 30, 2017, 03:13:23 PM »
Today I noticed that cci-reanalyser has updated their service to provide several new visual data sets on the condition of the arctic (and world). Significant new additions are their Snow Depth figures and 500hPA Geopot. Height.

Thanks for that snow depth map, Simon. Very useful.
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Re: The 2017/2018 freezing season
« Reply #396 on: November 30, 2017, 04:15:00 PM »
Welcome to the 'published' side of ASIB, Simon!
Arctic ice is healthy for children and other living things.

Neven

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Re: The 2017/2018 freezing season
« Reply #397 on: November 30, 2017, 04:36:52 PM »
Ask a Climatologist: Chukchi Sea ice at record low



The Chukchi Sea should be almost fully covered in sea ice by now. Instead, it’s mostly open water.

Brian Brettschneider, with our Ask a Climatologist segment, says the ice coverage right now in the Chukchi is typical for mid-October, not late-November.
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A-Team

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Re: The 2017/2018 freezing season
« Reply #398 on: November 30, 2017, 05:33:13 PM »
Here is a sea ice thickness product for 27 Sep to 30 Nov plus 9 day forecast taken from the Mercator Ocean site. They don't indicate its source but it is probably calibrated relative to the SMOS netCDF product at Copernicus described in #378 above. The thickness pattern bears some similarity to RASM-ESRL ice thickness.

It apparently shows frazil ice in the Chukchi that is treated as open water in UH AMSR2 (ie 0 concentration). Export out the Nares Strait is quite effective.

It is more convenient in some ways to view animations at the MercOcean site, for example salinity x depth from May-Nov are linked below though there's no practical way to capture these or rescale (other than full screen mode). They do work well as previews however. The forecast salinity for Dec 9th shows the freshening in the Beaufort Gyre to 318 m depth (but not beyond) as well as the Atlantic Water salt finger wrapping along the Svalbard/Siberian shelf.

MercOcean uses a javascript library called Leaflet which works ok overall but has various limitations and bugs. The server is quite fast. The site may be fairly new as most of the cross sections are not yet available.

http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20170501/20171130/2/1
http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20170501/20171130/2/2
http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20170501/20171130/2/3
http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20170501/20171130/2/4
« Last Edit: November 30, 2017, 06:50:07 PM by A-Team »

A-Team

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Re: The 2017/2018 freezing season
« Reply #399 on: November 30, 2017, 07:33:47 PM »
Hudson Bay  is freezing much faster than 2016 but pretty much in line with 2012 through 2015.
Right, it's been coldish there relative to way too warm 'everywhere' else (except Siberia).
« Last Edit: December 01, 2017, 12:51:22 AM by A-Team »