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jai mitchell

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Re: The 2016/2017 freezing season
« Reply #2400 on: January 31, 2017, 08:42:27 PM »
Yes, it would be nice if the dmi-graphs were centered on winter. Summers at +2m ASL can't rise very high as long as there's ice to melt. Cut and overlaid 2015-16 and 2016-17 winters, but as Neven said the FDD shows quite a deviation. Not that it does not show on this too.

this is fantastic!

don't like those pictures of Barents off of Barrow. . .If last year's barrow gyre is any indication, we are in for a very interesting melt season. . .

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FishOutofWater

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Re: The 2016/2017 freezing season
« Reply #2401 on: January 31, 2017, 09:06:41 PM »
Is it cause or effect?

Water vapor transport/sea ice loss/warming oceans/warming polar atmosphere/wavier northern hemisphere atmospheric circulation are coupled non-linear processes. It may be entertaining to argue chicken vs egg but it's pretty pointless. Linear thinking gets us into trouble in a nonlinear world.

I fear that this insanely warm Arctic winter is the beginning of a new atmospheric regime for the northern hemisphere that will be coupled with the disappearance of Arctic sea ice in late summer. Perhaps this won't be the year of an ice free September but this is the kind of winter I would expect to see before an ice free September. There's been not only extraordinarily warm weather and high ice export out of the Fram and Nares straits.  Moreover there's been greater than normal warm water import from the Atlantic over the past year.

I expect January's PIOMAS to be a record low. We'll soon see.

jai mitchell

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Re: The 2016/2017 freezing season
« Reply #2402 on: January 31, 2017, 09:28:05 PM »
This is a 4 standard deviation event in the stratosphere causing extreme upper altitude warming.  I have not seen any characterization of causality yet.  Very high geopotential height and temperature anomalies at the 10 hPa altitude level.

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Shared Humanity

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Re: The 2016/2017 freezing season
« Reply #2403 on: January 31, 2017, 09:32:35 PM »
I realize cause/effect is a foolish way to look at it. I was simply asking so that we would refocus on what is going on with the freeze.

Koop in VA

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Re: The 2016/2017 freezing season
« Reply #2404 on: February 01, 2017, 12:04:25 AM »
Hey George/FOOW,

Long time sea ice follower but relatively new lurker to Neven's site.  Anyway, you said:

Quote
There's been not only extraordinarily warm weather and high ice export out of the Fram and Nares straits.

I've seen DMI's metrics on the warmth provided by historical data on temperatures above 80 degrees and their daily updating confirms that this is an extremely warm winter for the Arctic.

I have further heard a lot of discussion here on the level of export out of the Fram and Nares.  But I don't think I've come across a site that has produced data on how much ice has been exported historically and how this year compares to the historic average or the years acknowledged as having a lot of export.

So I just want to clarify if we have data on this or it is mostly anecdotal evidence based on years of observing the satellite pictures.  I do recognize this is likely a hard thing to quantify as it would presumably be based on volume and the volume metrics seem to be sporadic, not in agreement with other ways to measure volume, and taken as a whole instead of region specific.

Any clarification on these issues may help me better understand the context for this freezing season.

Thanks.

subgeometer

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Re: The 2016/2017 freezing season
« Reply #2405 on: February 01, 2017, 02:17:30 AM »
Yes, it would be nice if the dmi-graphs were centered on winter. Summers at +2m ASL can't rise very high as long as there's ice to melt. Cut and overlaid 2015-16 and 2016-17 winters, but as Neven said the FDD shows quite a deviation. Not that it does not show on this too.

Displayed like this the change at Christmas 2015 is very clear. Since then, in addition to the outrageous spikes, temperatures haven't been able to fall to the average, let alone below, as if there is a floor at 247K

In the old regime there are also temp spikes, not so common maybe, but in any case they couldn't raise the temperature to the levels we see now because the baseline temperature was so much lower, like in this chart from 1961

Tigertown

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Re: The 2016/2017 freezing season
« Reply #2406 on: February 01, 2017, 03:16:25 AM »
A good view of things in the Bering Sea and Strait today.

epiphyte

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Re: The 2016/2017 freezing season
« Reply #2407 on: February 01, 2017, 05:39:52 AM »
Well...I thought I found exactly what I wanted to know...until I realized they cut off exactly the regions we care about.

http://www.ospo.noaa.gov/Products/bTPW/TPW_Animation.html?product=GLOBAL_PCT

That gave me a jolt for a moment. But from looking at the site this may not actually be a conspiracy - isn't all the data there coming from two geosynchronous satellites (GOES 13+15) which can't see the arctic?


budmantis

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Re: The 2016/2017 freezing season
« Reply #2408 on: February 01, 2017, 05:51:32 AM »

In the old regime there are also temp spikes, not so common maybe, but in any case they couldn't raise the temperature to the levels we see now because the baseline temperature was so much lower, like in this chart from 1961

Thanks for posting this Geo. What I find interesting is during the summer of 1961, the temperature exceeded the average for nearly 50% of the time (or more) during the melt season. The rest of the year spent a fair amount of time below average, unlike today.

subgeometer

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Re: The 2016/2017 freezing season
« Reply #2409 on: February 01, 2017, 06:45:39 AM »
2 worldview images of the same region of Bering Sea on 24Jan and 31 Jan - a rectangle from about 61.62/-168.7 to 62.2/-172.9/.

A lot of melt in the 2nd image

jdallen

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Re: The 2016/2017 freezing season
« Reply #2410 on: February 01, 2017, 09:21:06 AM »
2 worldview images of the same region of Bering Sea on 24Jan and 31 Jan - a rectangle from about 61.62/-168.7 to 62.2/-172.9/.

A lot of melt in the 2nd image
If you have a look at NOAA SST's, that melting is taking place almost exactly at the -1.5C gradient line.

If the ice starts off thin, and we have rough weather, it will definitely not survive long once it pushes past that threshold.  As it is, at that location, it will lose 1-2CM a day from bottom melt even undisturbed.

http://polar.ncep.noaa.gov/sst/ophi/color_newdisp_sst_north_pole_stereo_ophi0.png
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Re: The 2016/2017 freezing season
« Reply #2411 on: February 01, 2017, 09:34:34 AM »
What a magnificent shot -

EOSDIS worldview, land mask, Brightness temperature, band 31, night, temperature spread squashed to 232.5K to 273K, using a rainbow color spread.

The shattered state of the thickest ice in the Arctic immediately north of Greenland becomes readily apparent, as well as the fairly extraordinary temperatures along the Atlantic front from FJL to the Fram.

Linke below, partial image of the Atlantic side attached.

https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor(hidden),Land_Mask,MODIS_Aqua_Brightness_Temp_Band31_Night(opacity=0.99,palette=rainbow_1,min=232.5,max=273,squash),Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2017-01-31&z=3&v=-1002286.1748432323,-1341323.5587019399,1782993.8251567679,88180.44129806012

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seaicesailor

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Re: The 2016/2017 freezing season
« Reply #2412 on: February 01, 2017, 09:48:18 AM »
What a magnificent shot -


Indeed JD thanks for it!
From my side I had been playing with the worldview gif maker, which unfortunately doesn't allow to squeeze the pallette.
Still, this is the Arctic wide "AMSR2 sea ice brightness temperature 89H", from Jan 10 to Jan 31.

jdallen

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Re: The 2016/2017 freezing season
« Reply #2413 on: February 01, 2017, 09:52:17 AM »
What a magnificent shot -


Indeed JD thanks for it!
From my side I had been playing with the worldview gif maker, which unfortunately doesn't allow to squeeze the pallette.
Still, this is the Arctic wide "AMSR2 sea ice brightness temperature 89H", from Jan 10 to Jan 31.
The gif maker is great; I wanted a 'one shot' to illustrate how hammered the ice structure is.  Your gif does a good job of showing how the ice is over-running warmer water on the Atlantic side.
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Neven

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Re: The 2016/2017 freezing season
« Reply #2414 on: February 01, 2017, 10:18:00 AM »
Another comment by a new member released (as well as your profile, Koop, welcome):

Hey George/FOOW,

Long time sea ice follower but relatively new lurker to Neven's site.  Anyway, you said:

Quote
There's been not only extraordinarily warm weather and high ice export out of the Fram and Nares straits.

I've seen DMI's metrics on the warmth provided by historical data on temperatures above 80 degrees and their daily updating confirms that this is an extremely warm winter for the Arctic.

I have further heard a lot of discussion here on the level of export out of the Fram and Nares.  But I don't think I've come across a site that has produced data on how much ice has been exported historically and how this year compares to the historic average or the years acknowledged as having a lot of export.

So I just want to clarify if we have data on this or it is mostly anecdotal evidence based on years of observing the satellite pictures.  I do recognize this is likely a hard thing to quantify as it would presumably be based on volume and the volume metrics seem to be sporadic, not in agreement with other ways to measure volume, and taken as a whole instead of region specific.

Any clarification on these issues may help me better understand the context for this freezing season.

Thanks.
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bairgon

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Re: The 2016/2017 freezing season
« Reply #2415 on: February 01, 2017, 11:23:56 AM »
Great link.

Take a look at this - and go back and forwards a few days: https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor(hidden),Land_Mask,MODIS_Aqua_Brightness_Temp_Band31_Night(opacity=0.99,palette=rainbow_1,min=225.5,max=280.6,squash),Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2017-01-30&z=3&v=-1790892.4347313605,-1733361.5598989956,175187.5652686396,-724721.5598989956

For best visibility, click on the Layer Options for the Bright Temperature layer, and reduce the upper threshold to about 280K or so.

What strikes me is the export out of Nares, also visible on Sentinel. There is a large chunk of ice about 100km long which has just separated out of the bay on the south of Nares (edit: Kane Basin) and is starting to fracture, melt, and move down the strait.

In addition, the Parry Channel from Baffin Bay up to Resolute is opening up, just like Nares. I have no idea whether this is normal - but given the time of year, I would guess not.
« Last Edit: February 01, 2017, 11:48:38 AM by bairgon »

Pmt111500

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Re: The 2016/2017 freezing season
« Reply #2416 on: February 01, 2017, 12:05:09 PM »
thanks bairgon, somewhat gone are the days when we couldn't see anything in the Polar Winter Night.
Cut the image from the bad sectors getting messed up by storms or clouds or whatever but still. Cloud streets forming in the right side towards Atlantic.
« Last Edit: February 01, 2017, 12:23:48 PM by Pmt111500 »
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Re: The 2016/2017 freezing season
« Reply #2417 on: February 01, 2017, 12:20:57 PM »
I wanted to post my Fram update, but saw many great links (Worldview), thanks to all. Warm areas: Feb 1 - Beaufort; Feb 2 - Chuckchi, ESS, Svalbard; Feb 3 - Chuckchi, ESS, Beaufort, Svalbard; Feb 4 - Chuckchi, ESS, Beaufort, Svalbard, FJL; Feb 5 - Chuckchi, ESS, Beaufort, Svalbard, FJL; Feb 6 - North Pole, Svalbard, FJL, Kara; Feb 7 - Svalbard, FJL, Kara, Greenland; Feb 8 - Svalbard, FJL, Kara, Laptev, Greenland. Anomalies reaching +30 Celsius all days Feb 1 - Feb 8 (Climate Reanalyzer). Svalbard Airport extremely warm until Feb 10, what will be February average there (long-term average -16.2 Celsius)?
« Last Edit: February 01, 2017, 12:26:07 PM by romett1 »

Jim Williams

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Re: The 2016/2017 freezing season
« Reply #2418 on: February 01, 2017, 02:43:43 PM »
Well...I thought I found exactly what I wanted to know...until I realized they cut off exactly the regions we care about.

http://www.ospo.noaa.gov/Products/bTPW/TPW_Animation.html?product=GLOBAL_PCT

That gave me a jolt for a moment. But from looking at the site this may not actually be a conspiracy - isn't all the data there coming from two geosynchronous satellites (GOES 13+15) which can't see the arctic?

I figured it was because they didn't have the data, but I was still disappointed.  I really really want to know how anomalous the water vapor in the Arctic is.

jgnfld

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Re: The 2016/2017 freezing season
« Reply #2419 on: February 01, 2017, 02:54:07 PM »
...Svalbard Airport extremely warm until Feb 10, what will be February average there (long-term average -16.2 Celsius)?

Interestingly, the sun doesn't come up until Feb 15 (though twilights are getting stronger).

epiphyte

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Re: The 2016/2017 freezing season
« Reply #2420 on: February 01, 2017, 04:51:55 PM »
Well...I thought I found exactly what I wanted to know...until I realized they cut off exactly the regions we care about.

http://www.ospo.noaa.gov/Products/bTPW/TPW_Animation.html?product=GLOBAL_PCT

That gave me a jolt for a moment. But from looking at the site this may not actually be a conspiracy - isn't all the data there coming from two geosynchronous satellites (GOES 13+15) which can't see the arctic?

I figured it was because they didn't have the data, but I was still disappointed.  I really really want to know how anomalous the water vapor in the Arctic is.

Nullschool has tabs for TPW, TCW and 3 hour precip... from those it looks to my untutored eye to be dry as a bone right now... but over the next 12 hours enough to cause a little precip ? (5-10mm total at a guess) in the area north of Svalbard... viz:

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Re: The 2016/2017 freezing season
« Reply #2421 on: February 01, 2017, 06:43:44 PM »
Well...I thought I found exactly what I wanted to know...until I realized they cut off exactly the regions we care about.

http://www.ospo.noaa.gov/Products/bTPW/TPW_Animation.html?product=GLOBAL_PCT
That gave me a jolt for a moment. But from looking at the site this may not actually be a conspiracy - isn't all the data there coming from two geosynchronous satellites (GOES 13+15) which can't see the arctic?

I figured it was because they didn't have the data, but I was still disappointed.  I really really want to know how anomalous the water vapor in the Arctic is.

Nullschool has tabs for TPW, TCW and 3 hour precip... from those it looks to my untutored eye to be dry as a bone right now... but over the next 12 hours enough to cause a little precip ? (5-10mm total at a guess) in the area north of Svalbard... viz:
I know, but dry as a bone can still easily be over 300% of normal.  What I don't know is what NORMAL was -- and since I think this freezing season is all about the switch from a desert climate to an ocean climate that is something I think would say a lot.

epiphyte

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Re: The 2016/2017 freezing season
« Reply #2422 on: February 01, 2017, 07:01:14 PM »
This is a 4 standard deviation event in the stratosphere causing extreme upper altitude warming.  I have not seen any characterization of causality yet.  Very high geopotential height and temperature anomalies at the 10 hPa altitude level.

Windspeed also appears beyond freaky up there...

Tigertown

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Re: The 2016/2017 freezing season
« Reply #2423 on: February 01, 2017, 08:17:27 PM »
It looks like like we just took another hit on volume. One step forward, two steps back, I suppose.
Could it be the ice getting pushed into the "hot" zone or maybe melting in the Bering? Fram and Nares export, maybe?

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Re: The 2016/2017 freezing season
« Reply #2424 on: February 01, 2017, 08:29:57 PM »
What a magnificent shot -

EOSDIS worldview, land mask, Brightness temperature, band 31, night, temperature spread squashed to 232.5K to 273K, using a rainbow color spread.

The shattered state of the thickest ice in the Arctic immediately north of Greenland becomes readily apparent, as well as the fairly extraordinary temperatures along the Atlantic front from FJL to the Fram.

Linke below, partial image of the Atlantic side attached.

https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor(hidden),Land_Mask,MODIS_Aqua_Brightness_Temp_Band31_Night(opacity=0.99,palette=rainbow_1,min=232.5,max=273,squash),Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2017-01-31&z=3&v=-1002286.1748432323,-1341323.5587019399,1782993.8251567679,88180.44129806012
Put this up to stupid questions but how do you not apply the land mask as I want to look at Jakoshovn and this does Ice quite well but...  The land mask cuts off the calving face.

Jim Hunt

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Re: The 2016/2017 freezing season
« Reply #2425 on: February 01, 2017, 09:01:08 PM »
Put this up to stupid questions but how do you not apply the land mask as I want to look at Jakoshovn and this does Ice quite well but...  The land mask cuts off the calving face.

Click the "eye" next to "Land Mask" in the "Layers" drop down at top left.
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Jim Hunt

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Re: The 2016/2017 freezing season
« Reply #2426 on: February 01, 2017, 09:11:19 PM »
James Screen is live tweeting from the "Arctic Change and Its Influence on Mid-Latitude Climate and Weather" workshop in Washington DC. This one particularly caught my eye:

Quote
[Judah Cohen] challenges Jim Overland's assertion that Arctic reinforces but cannot drive circulation change. Plenty to discuss later.

James assures me that:

Quote
There will be write-ups in the following weeks/months.

Meanwhile Judah tweeted this:

Reality is merely an illusion, albeit a very persistent one - Albert Einstein

jdallen

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Re: The 2016/2017 freezing season
« Reply #2427 on: February 01, 2017, 10:12:14 PM »
James Screen is live tweeting from the "Arctic Change and Its Influence on Mid-Latitude Climate and Weather" workshop in Washington DC. This one particularly caught my eye:

Quote
[Judah Cohen] challenges Jim Overland's assertion that Arctic reinforces but cannot drive circulation change. Plenty to discuss later.

James assures me that:

Quote
There will be write-ups in the following weeks/months.

Meanwhile Judah tweeted this:
Not sure I understand the full implications of the changes in pressure being presented.  What is it that this expected February geopotential height anomaly will do?
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Tigertown

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Re: The 2016/2017 freezing season
« Reply #2428 on: February 01, 2017, 10:30:19 PM »
@jdallen
I just found this and don't know if it helps yet or not, as i need to read in more detail.
Maybe you can make better of it than myself.
https://www.aer.com/science-research/climate-weather/arctic-oscillation

Jim Hunt

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Re: The 2016/2017 freezing season
« Reply #2429 on: February 02, 2017, 12:18:53 AM »
Not sure I understand the full implications of the changes in pressure being presented.  What is it that this expected February geopotential height anomaly will do?

Scroll through Judah's Twitter feed, or read his blog as suggested by TT? Potential SSW => WACC setup. In summary:
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Tigertown

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Re: The 2016/2017 freezing season
« Reply #2430 on: February 02, 2017, 02:11:27 AM »
https://www.washingtonpost.com/news/capital-weather-gang/wp/2017/02/01/beyond-the-extreme-scientists-marvel-at-increasingly-non-natural-arctic-warmth/?utm_term=.eb34223c27c2

Article by Jason Samenow has a lot of familiar names and charts.

Excerpt,
{The number of freezing degree days is far lower than any other period on record. Eric Holthaus, a meteorologist and science writer who first posted the chart to Twitter, remarked it illustrated a “stunning lack of freezing power” over the Arctic. “This is happening now,” he added. “Not in 50 or 100 years — now.”

The chart was created by Nico Sun, a citizen scientist, using temperature data from the high Arctic, north of 80 degrees latitude, furnished by the Danish Meteorological Institute.}

From Zack Labe


https://twitter.com/ZLabe/status/826110396524220416/photo/1


Ice Shieldz

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Re: The 2016/2017 freezing season
« Reply #2431 on: February 02, 2017, 02:37:54 AM »
NOAA's ESRL 70N-90N air temps for Jan 2017 indicated even higher record heat than DMI's 80N-90N.  For an apples to apples comparison see the charts below for ESRL 70N-90N followed by ESRL 80N-90N.

This more southerly heat concentration can be seen in the mean temp anom maps where much more heat has been concentrating toward barents-kara sea and bering-chukchi seas.

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Re: The 2016/2017 freezing season
« Reply #2432 on: February 02, 2017, 03:08:50 AM »
Ice Shieldz,

It's certainly been hot in the Arctic lately, but unfortunately, your chart is not showing us Jan 2017. The NCEP Reanalysis has not updated yet. Your chart shows Jan 2016 as the last data point.

I'm waiting impatiently as well for the next update.

Archimid

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Re: The 2016/2017 freezing season
« Reply #2433 on: February 02, 2017, 03:16:32 AM »
Ice Shieldz,

It's certainly been hot in the Arctic lately, but unfortunately, your chart is not showing us Jan 2017. The NCEP Reanalysis has not updated yet. Your chart shows Jan 2016 as the last data point.

I'm waiting impatiently as well for the next update.

If this is true, I expect the anomaly to be even worse. As a record low extent year, there has been much more open water in the periphery than before, with crazy hot air intrusions.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

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Re: The 2016/2017 freezing season
« Reply #2434 on: February 02, 2017, 03:30:53 AM »
My current understanding/prejudice is that the most reliable thickness data for the current Arctic sea ice is the Cryosat NRT data from CPOM:
http://www.cpom.ucl.ac.uk/csopr/seaice.html.

As I understand it, that data set is from actual measurements rather than models. Also, I haven't heard so far of any reason not to trust its accuracy.

 Is that fair? I have no reason for bias but am simply an amateur.



So I wanted to compare this year's status to previous years, using that site. Only certain data sets are readily available that I can see, and so the gif below shows some sort of apples-to-oranges comparison.

The frames are, in order
1) Latest 5km Grid of 28-day Thickness : 2/1/17 - 29/1/17 (shows for 200 ms)
2) Thickness over March+April 2011 (shows for 50 ms) = "Spring 2011"
3) Spring 2012
4) Spring 2013
5) Spring 2014
(Those are the only years I can see readily available.)

So basically its comparing the ice thickness around mid-January 2017 with that around the end of March for 2011 to 2014.

So we have to imagine how much ice will be added over the next month-and-a-half if we want to see if we are worse off, or better off, than in those previous years.

  The worst ice situation from those previous years was in 2013.

   As can be seen from the gif, the ice pack in the vertical middle of the plot - i.e. excluding the Beaufort, Chukchi and Bering Sea on the Pacific Side and the Barents, Kara etc on the Atlantic side - was not really worse than currently. Add another month-and-a-half of ice growth and that part might generally be thicker in Spring 2017 than it was in 2013.

(Say add about a half-metre of ice then, roughly:
dark blue -> light blue
light blue -> green
green -> yellow
yellow -> red
etc.)

So the vertical-centre part as described above will probably not be the weakness this Spring.

Instead, the worry is the Pacific and, particularly, Atlantic peripheral seas. These are seen to have much less ice than in previous years, albeit shown 1.5 months later.

The worst sea in the comparison is probably the Barents Sea. Unless the ice is added there, quickly and dramatically, the Barents Sea is likely to melt out early in the upcoming melt season. That, in turn, might make the whole Atlantic side into a 'kill zone' for any ice drifting over there during the melt season.

On the Pacific side, the Beaufort, Bering and Chukchi Seas might also melt out earlier in the 2017 melt season than they did in 2011-14, forming another 'kill zone', on the Pacific side. We already saw that feature in 2015 and, even more, last year.



  In summary, a quick comparison was made of the available CPOM CryoSat NRT Arctic sea ice thickness data for this January vs. Spring in 2011-14. The main conclusion is that the sea ice this melt season looks likely to be vulnerable on the Atlantic (mainly) and also Pacific sides. Now it's all up to the weather and currents over the next six months.



The gif needs a click to start.

Tigertown

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Re: The 2016/2017 freezing season
« Reply #2435 on: February 02, 2017, 03:40:07 AM »
I personally think those thickness numbers are on the high side, and that the majority of the ice is between one to one & one-half a meter, but feel free to wait on a second opinion. As far as what happens to any of the ice in the Spring, it has to make it to Spring first. The immediate forecast calls for more of the same, and its starting to look like a one-way street for the rest of the "freezing" season.

Archimid

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Re: The 2016/2017 freezing season
« Reply #2436 on: February 02, 2017, 04:01:34 AM »
Thanks slowwing. That's a nice riddle. This is my interpretation of it.

Over Chukchi/ Beaufort in January 2017 it seems to me that the average thickness lies somewhere between blue and green. Using the legend I would guesstimate an average thickness of about a meter. The rest of the "spring" maps seem to be somewhere between green and yellow, with specks of red. Using the legend I would put it somewhere between 2-2.25 meters on average.

 so about a meter of growth is needed for this year to match the thickness of the previous springs. So the question I have is, how many FDD's are needed to thicken ice from 1 m to 2 m? Will we get that in the next 6 weeks?
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CognitiveBias

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Re: The 2016/2017 freezing season
« Reply #2437 on: February 02, 2017, 04:19:07 AM »
The many discussions of the FDD 80N piqued my interest in the distribution of those temperature anomalies.  The Atlantic side typically appears to be much warmer, and for a time I held some hope that significant cold on over the Pacific side of the CAB may lead to some sort of rebound...

Attached is the result of my first attempt to analyze ECMWF data.  Its a look at a transection at 81N.  Included is all daily temperature data across December for the years 2000-2016 at 3 degree longitude intervals around the 81N latitude line.  Starting at 0E up past Svalbard, Kara, ESS, etc.

The Svalbard and FJL areas show the most significant warming trend while parts of the CAA have actually cooled.
« Last Edit: February 02, 2017, 04:26:14 AM by CognitiveBias »

jdallen

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Re: The 2016/2017 freezing season
« Reply #2438 on: February 02, 2017, 04:22:45 AM »
Thanks slowwing. That's a nice riddle. This is my interpretation of it.

<snip> so about a meter of growth is needed for this year to match the thickness of the previous springs. So the question I have is, how many FDD's are needed to thicken ice from 1 m to 2 m? Will we get that in the next 6 weeks?
Just under 2900 by my estimation (Lebedev formula)

Typical FDD's between now and the end of the season (mid-April) looks to run at about 2500.

If the heat we're seeing continues, and we get the same kind of deficit as we saw last year, we'll only get about 1500, if we are lucky.  QED - we'll be lucky to get another half-meter of ice between now and the end of the refreeze.
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Archimid

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Re: The 2016/2017 freezing season
« Reply #2439 on: February 02, 2017, 04:30:07 AM »
Thanks jdallen.
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Tigertown

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Re: The 2016/2017 freezing season
« Reply #2440 on: February 02, 2017, 04:37:28 AM »
I like this thickness map from Sentinel-1 data.
It also gives a readout for a pointed location. The numbers corresponded well to the calculations ktonine and Tealight made earlier this season from FDD's.

Tigertown

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Re: The 2016/2017 freezing season
« Reply #2441 on: February 02, 2017, 05:13:10 AM »
Most of these LP systems loose some strength as they get further north into the Arctic. I can't say much about what is supposed to become of this one yet, as the forecast ends with it at 953 hpa.
It looks like, even if it doesn't move further north, it will send a lot of moisture to the CAB.
Second Click image is an abbreviated gif from http://cci-reanalyzer.org/wx/fcst/#GFS-025deg.ARC-LEA.PWTR
« Last Edit: February 02, 2017, 06:08:39 AM by Tigertown »

Ice Shieldz

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Re: The 2016/2017 freezing season
« Reply #2442 on: February 02, 2017, 06:07:40 AM »
Ice Shieldz,

It's certainly been hot in the Arctic lately, but unfortunately, your chart is not showing us Jan 2017. The NCEP Reanalysis has not updated yet. Your chart shows Jan 2016 as the last data point.

I'm waiting impatiently as well for the next update.

thanks wehappyfew, I was thinking that it might not be updated as I couldn't distinguish the two jumps associated with both 2016 and 2017.

DrTskoul

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Re: The 2016/2017 freezing season
« Reply #2443 on: February 02, 2017, 06:57:25 AM »
Btw cryostat results are also the output of a model ( albeit one informed by radiation timing data ). So assumptions about state of ice/snow/freeboard are important for the model based translation to thickness.
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slow wing

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Re: The 2016/2017 freezing season
« Reply #2444 on: February 02, 2017, 07:07:12 AM »
Yes, this FDD (Freezing Degree Days) is a nice idea to get a handle on the depth of ice expected.

The FDD 80N is just a one-parameter measure. Cognitive Bias has posted a couple of other such measures above, at #2438. Yet another one would be the average FDD over a defined boundary for the Arctic Basin "the FDD Arctic Basin".

 This freezing season's anomaly in the FDD 80N parameter appears to come largely from the Atlantic side, particularly around the Barents Sea area where the open water is - at least that is the impression I get from the daily temperature maps and temperature anomaly.

I'm wondering if FDD Arctic Basin would show quite as large an anomaly? Have the temperature anomalies been as large on the Beaufort Sea side of the Arctic Basin? I haven't followed it closely enough to confidently answer that one.


   As an extension to this analytical tool, a daily FDD map could be constructed from the daily temperature map for the freezing season up to the current date  ("FDD-to-date map") over the Arctic Basin. (Specifically, just add the "freezing degrees" for the day at each location to the accumulated FDD value at that location from yesterday's map.)

   Neglecting ice movement, such a map would predict - using the Lebedev formula or the other one - ice thickness at each date and for each location within the Arctic Basin (at least where there was no ice at the start of the freeze season, as well as where the initial thickness was known or estimated).

   Would that simple thickness prediction correspond well with the actual measured thickness at each location? It ignores factors such as water temperature and salinity below the ice. Even if not, would the difference give us information on those and other factors at each location? Also, the Lebedev parameterization could be assessed and improved.

  Unfortunately I have neither the time nor the coding wherewithal to create and keep current such an FDD-to-date map. But anyway that is a suggested extension to the interesting concept of FDD if anyone happens to be interested.
« Last Edit: February 02, 2017, 07:22:55 AM by slow wing »

Tigertown

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Re: The 2016/2017 freezing season
« Reply #2445 on: February 02, 2017, 07:32:40 AM »
@slow wing

I think what you mentioned about movement may be the biggest obstacle to tracking FDD's by region. We have lost a good portion of the thickest ice to storms, much of it to one storm in particular. That is just what we know about. I posted a volume chart by Wipneus earlier based on JAXA data, and it shows a couple drops in volume. I would think that a good deal of that volume loss each time was from thickness loss, rather than simply extent loss alone. So, it gets kind of complicated, trying to allow for movement and storm loss both.

Cocos

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Re: The 2016/2017 freezing season
« Reply #2446 on: February 02, 2017, 07:45:44 AM »
I have been lurking in the forum for a while, am very interested but not really able to contribute to the discussion.

Just wanted to point out datas from a the new Sentinel 3A  Copernicus satellite are available since January 2017.
http://www.esa.int/spaceinimages/Images/2016/12/Sentinel-3A_measures_height_of_Antarctic_ice_sheet

https://sentinels.copernicus.eu/web/sentinel/news/-/article/sentinel-3-sral-level-1b-and-level-2-products-available-in-the-data-hub

Data hub con be found here: https://scihub.copernicus.eu/s3/#/home . You need to register afterwards you can access the data of ( now) Sentinel 1 A and B Sentinel 2 and Sentinel 3A for free.
Sentinel-3 is currently in its Ramp-up Phase. https://sentinels.copernicus.eu/web/sentinel/news/-/article/sentinel-3-data-benefit-users
Excerpt:
January 2017   Release of SRAL L1B core data to all users

The toolbox is available here: http://step.esa.int/main/download/
ESA built and launched Sentinel 3. It is being operated by EUMETSAT http://www.eumetsat.int/website/home/News/DAT_3349917.html


Also wanted to point out CryoSMOS which is already used by some here in the forum
http://www.esa.int/Our_Activities/Observing_the_Earth/SMOS/Satellite_cousins_have_ice_covered

I hope this information was useful to some.
Maybe i posted it in the wrong thread, feel free to move it to wherever the info might be useful.

Thanks to all who provide so much interesting information here in ASIF.

 Back into lurking mode

slow wing

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Re: The 2016/2017 freezing season
« Reply #2447 on: February 02, 2017, 07:58:32 AM »
Thanks for your reply, Tigertown.

  I agree up to a point.

  However, the FDD daily map itself is actually dead easy to do given the daily temperature maps for the Arctic Basin. As I said, one simply increments the FDD value at each location by the degrees freezing for the day at that location. Done!

  That procedure gives a perfectly well defined FDD-to-date map.

   I would suggest also that this FDD is intrinsically interesting - it tells you how cold each location or region of the Arctic Basin has been during the freezing season. That extends greatly on e.g. the one parameter information available from the FDD 80N graph.

  The maps can be compared for different years. E.g. "has the Beaufort Sea been colder than usual this freeze season?"

 
 The FDD 80N graph itself can be derived from the FDD-to-date maps, as can FDD graphs for the entire Arctic Basin or for any other defined region. So the maps are useful for that purpose as well.




  Where the issues of drift etc. come in is when one tries to derive an ice thickness map from the FDD daily map, e.g. using the Lebedev formula. As you suggest, the corrections, or else the uncorrected deviations, might be quite large. How large? It might be quite interesting in and of itself to find out. To the extent the ice depth prediction has interest, correction procedures can be come up with and applied.
« Last Edit: February 02, 2017, 08:05:55 AM by slow wing »

Neven

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Re: The 2016/2017 freezing season
« Reply #2448 on: February 02, 2017, 09:39:10 AM »
I have been lurking in the forum for a while, am very interested but not really able to contribute to the discussion.

Just wanted to point out datas from a the new Sentinel 3A  Copernicus satellite are available since January 2017.
http://www.esa.int/spaceinimages/Images/2016/12/Sentinel-3A_measures_height_of_Antarctic_ice_sheet

https://sentinels.copernicus.eu/web/sentinel/news/-/article/sentinel-3-sral-level-1b-and-level-2-products-available-in-the-data-hub

Data hub con be found here: https://scihub.copernicus.eu/s3/#/home . You need to register afterwards you can access the data of ( now) Sentinel 1 A and B Sentinel 2 and Sentinel 3A for free.
Sentinel-3 is currently in its Ramp-up Phase. https://sentinels.copernicus.eu/web/sentinel/news/-/article/sentinel-3-data-benefit-users
Excerpt:
January 2017   Release of SRAL L1B core data to all users

The toolbox is available here: http://step.esa.int/main/download/
ESA built and launched Sentinel 3. It is being operated by EUMETSAT http://www.eumetsat.int/website/home/News/DAT_3349917.html


Also wanted to point out CryoSMOS which is already used by some here in the forum
http://www.esa.int/Our_Activities/Observing_the_Earth/SMOS/Satellite_cousins_have_ice_covered

I hope this information was useful to some.
Maybe i posted it in the wrong thread, feel free to move it to wherever the info might be useful.

Thanks to all who provide so much interesting information here in ASIF.

 Back into lurking mode

Thanks for the interesting links, Cocos! And welcome (your profile is released now, so you can post freely).
Compare, compare, compare

subgeometer

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Re: The 2016/2017 freezing season
« Reply #2449 on: February 02, 2017, 10:24:01 AM »
SlowWing From watching forecasts over the winter my impression is FDDs have been closest to normal in a strip from the New Siberian islands to CAA in centre of the basin

ie far enough away from Atlantic and Pacific warm air intrusions