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Messages - Iain

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1
Arctic sea ice / Re: The 2019 melting season
« on: August 19, 2019, 01:16:16 PM »
Southward movement has restarted in Nares and between some of the Islands of the CAA: Borden, Ellef Ringes, Meighen and Ellesmere, also the South end of Parry Channel
Map here:
https://en.wikipedia.org/wiki/Arctic_Archipelago

Wind has been light over the last few days (Gif is for 15th to 18th Aug) so this is this is mostly ocean current driven.

South of the floes is clear blue ocean, so the potential for export over the next 6 weeks (2 w past the expected minimum date) is high.

2
Arctic sea ice / Re: The 2019 melting season
« on: August 05, 2019, 12:47:47 AM »

My naive reaction is that those anomalies around the CAA suggest that a complete melt out is possible there.
[/quote]

The thickness in most of the CAA is already very low according to PIOMAS, so I agree.
[/quote]

The tidal flow is generally from North to South through the CAA, so the CAA gets filled with floes from the CAB. Recently the wind has been from the South, preventing the usual South going export, but it looks like that has restarted.

The breakup of the first channel from CAB to Parry Chanel occurred at the end of July, the earliest on a tie with 2012. The export flow has continued into October in the past.

3
Arctic sea ice / Re: The 2019 melting season
« on: July 29, 2019, 04:48:22 AM »
CAA - There is cracking in the landfast ice all the way to the CAB. That's early, but not unprecedented. As near as I can, visibility permitting, the same event happend on these dates in the recent past:

2018 Aug 15
2017 Aug 22
2016 Between July 30 and Aug 04 (thick cloud)
2015 Jul 31
2014 Sept 12
2013 between Aug 11 and Aug 22 (thick cloud)
2012 July 28

4
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 17, 2019, 05:31:41 PM »
Dispersal showing up as a left swerve on Chartic.

5
Greenland and Arctic Circle / Re: The 'Very Big Chunk' poll
« on: May 12, 2019, 09:01:09 PM »
Confirmed on Worldview. Shattered. I'm not optimistic Nares will block until winter.

6
Greenland and Arctic Circle / Re: The 'Very Big Chunk' poll
« on: May 06, 2019, 11:09:57 PM »
From what I've seen so far, very unlikely that the remaining FBCs (Fairly big.....: ) will block the channel.


7
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: May 06, 2019, 10:56:56 PM »
VBC has broken further with the rest of the FBCs (Fairly big....) separating from the arch. The grey infill looks like cloud, not refreeze - there is clear blue water in the strait

8
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: May 05, 2019, 10:18:31 AM »
VBC has split in half.

10
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: April 05, 2019, 11:11:39 AM »
Fracture of a slab of landfast ice at the narrow near Inglefield Land

11
Arctic sea ice / Re: The 2019 melting season
« on: March 11, 2019, 09:11:32 PM »
Not a serious objection, but shouldn't the extent uptick be discussed in the freezing thread rather than the melting thread?

More freez-ing happening than melt-ing (extent wise) is the reason for the uptick.



12
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 11, 2019, 04:00:12 PM »
Here's the throw,
Here's the play at the plate,
Holy cow.....

13
Greenland and Arctic Circle / Re: Old ice moving through Nares Strait
« on: March 10, 2019, 09:58:14 AM »
And there is still movement along the full length.

Potentially significant because:

The date has passed when it blocked last year
The sun is coming up
Though narrow, there is a fast current carrying the ice southwards. Only a strong South wind would halt or reverse the floes
There is an accumulation of thick ice nearby, against the N coast of Greenland and the CAA.
Much of that is fragmented

One to watch

14
Greenland and Arctic Circle / Re: Old ice moving through Nares Strait
« on: March 10, 2019, 09:47:11 AM »
Better view on Polar View

15
Greenland and Arctic Circle / Re: Old ice moving through Nares Strait
« on: March 10, 2019, 09:43:25 AM »
Look like new ice is entering from the North.

16
Greenland and Arctic Circle / Re: Old ice moving through Nares Strait
« on: March 04, 2019, 11:14:51 PM »
I think it would depend largely on Sea Surface Temperature, as Nares is the first left turn exit for the Atlantic drift,  but my goto source for day to day graphics has a snapshot archive for 2017 but not '18:

https://www7320.nrlssc.navy.mil/hycomARC/navo/arc_list_arcticsst.html

Ignore the warning, advanced > allow exception

So I can't decide.

17
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 02, 2019, 10:28:36 AM »
Meanwhile, there is still movement in the Nares straight at both ends. This time last year it was static at the Southern end on March 8th. Cloud obscured the view in the preceding days, so it may have blocked earlier.

https://worldview.earthdata.nasa.gov

Oh, and my post count has  stuck on 34. Not bothered for myself but others may be affected.

18
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 02, 2019, 10:01:29 AM »
Oops, I should have cited the source - NSIDC.

https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/


19
Arctic sea ice / Re: The 2018/2019 freezing season
« on: March 01, 2019, 03:16:04 PM »
I’m not calling the maximum, I’ll leave that to a more frequent poster, only that I think it is more likely than not the max is already past.

Because:

Mar 1st is the long term 1981 to 2010 peak
2019 would have to climb 0.113 M km2 to exceed the Feb 25th extent
DMI shows above average temperature for most of the arctic
The Climate re-analyser 3 day forecast shows above average temperature for most of the arctic, though not on the Atlantic periphery

20
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 26, 2018, 03:40:37 PM »
2018 growth has accelerated, 2016 is now the lowest extent for October 25th, 2018 2nd lowest.

Is there such a measure as extent days or volume days, or average extent/volume for a month or so either side of the max and min?

The PIOMAS page publishes a graph of summer minimum and winter maximum volumes with a linear trend of loss per decade.

Taking only the max and mins each year yields spikey data, the averages above I expect to be smoother, so the observed values would deviate less from a linear trend line.

21
Arctic sea ice / Re: The 2018/2019 freezing season
« on: October 25, 2018, 03:23:30 PM »
Extent for day of year now lowest since '79 on NSIDC.

Oct 24th 2018: 6.546 M km^2
Oct 24th 2016 (not shown for clarity) 6.622 M km^2

22
Arctic sea ice / Re: The 2018 melting season
« on: September 25, 2018, 03:15:12 PM »
It's not over yet, 2018 extent is still flatlining. It's now lower for the day of year than any year since 2000 except 07 and 12.

23
Arctic sea ice / Re: The 2018 melting season
« on: July 23, 2018, 01:42:54 PM »
Ice breakup in the CAA North of Cornwallis Island

About a week earlier than in 2017

There are still ice bridges intact at the southern end either side of CI and c. 200km of landfast ice to the north to the CAB

Winds are from the North for the next few days which will add pressure to the ice bridges

It’s one to watch. In the last few years the ice did not become mobile all the way to the CAB until late Sept / early Oct, so there was limited time for export of the thick CAB ice prior to refreeze. If it breaks up earlier, with the prevailing current from the north, there is potential for substantial export of the most resilient ice.

24
Arctic sea ice / Re: The 2018 melting season
« on: July 02, 2018, 07:09:33 AM »
Yearly comparison of HYCOM CICE thickness for July 1st (June 30th on 2017 for the nearest date with data). Click to animate.

<edit - oops, the above is a quote, the below is my comment>
Thanks for the animation. My main takeaway is the reduction of thick ice North of the CAA.

In recent years the CAA ice broke up late Sept/early Oct.

This year the breakup in Parry has progressed less far for the time of year than in 14-17, though it has been largely cooler than average so far. One to watch.

25
Arctic sea ice / Re: The 2018 melting season
« on: June 20, 2018, 07:05:50 AM »
Breakup in the Perry Channel. Clouds make it hard to see the extent. Polar view does not have an image of the area post breakup yet.

https://worldview.earthdata.nasa.gov


26
Arctic sea ice / Re: The 2017/2018 freezing season
« on: January 17, 2018, 01:18:48 PM »
Jim,

There was some discussion around FDDs this time last year in the 16/17 freezing thread.

From memory, the gist was that for any given temp difference between cold air and above-freezing seawater, the Ice thickness tends to a particular value.

The upshot was that the dT in the period immediately prior to onset of spring melting was the most important for thickness and summer survivability. FDDs at the onset of Autumn freezing made much less difference.

27
Arctic sea ice / Re: The 2017/2018 freezing season
« on: December 30, 2017, 11:56:00 AM »
bosbas,

It was updated at 03:00 today, but averaged from the last couple of days. From the site:

"Averaging period and the update timing of daily data : In general, sea-ice extent is defined as a temporal average of several days (e.g., five days) in order to eliminate calculation errors due to a lack of data (e.g., for traditional microwave sensors such as SMMR and SSM/I). However, we adopt the average of latest two days (day:N & day:N-1) to achieve rapid data release. Only for the processing of WindSat data (Oct. 4, 2011 to the present) the data of the day before yesterday (day:N-2) is also sometimes used to fill data gaps."

Charctic updates mid afternoon from memory:
https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

28
Arctic sea ice / Re: The 2017/2018 freezing season
« on: December 30, 2017, 10:47:10 AM »

29
Arctic sea ice / Re: The 2017 melting season
« on: June 05, 2017, 11:01:14 PM »
Ice breakup at the SE end of Parry Channel

30
Arctic sea ice / Re: The 2017 melting season
« on: April 03, 2017, 01:53:19 PM »
Are the purple and mauve areas inside the 85 deg latitude, indicating 400 – 500 mm of thickness for real?

Or are they a false reading at the edge of the scan for some reason?

31
Arctic sea ice / Re: The 2017 melting season
« on: March 25, 2017, 01:39:29 PM »
Visual confirmation the ice is moving along the full length of Nares strait and Robeson channel, however the grain size of the ice in the CAB is still too large to enter.

Meanwhile Parry channel, a conduit for ice getting through the CAA to enter Baffin bay, is still blocked between Somerset and Devon islands by an arch of ice. In 2016 it didn't break until 2nd of July. One to watch.

32
Arctic sea ice / Re: The 2017 melting season
« on: March 21, 2017, 10:42:42 PM »
<no off-topic stuff in this thread, especially when related to Donnie Tiny Hands. Take it elsewhere; N.>

33
Arctic sea ice / Re: The 2016/2017 freezing season
« on: March 07, 2017, 01:05:00 PM »
@meddoc

Not sure what you mean.

NB: It's funded by Europe,  so safe from any Trumpheting.

34
Arctic sea ice / Re: The 2016/2017 freezing season
« on: March 07, 2017, 08:03:17 AM »
Sentinel 2B got off the ground successfully.

http://www.bbc.co.uk/news/science-environment-39183353

"Sentinel-2B carries a large camera to image all land surfaces and coastal waters in visible and infrared light."

"Cryosphere: Mapping snow fields and glacier melting"


35
Arctic sea ice / Re: The 2016/2017 freezing season
« on: March 05, 2017, 01:00:23 PM »
@Jim - Great, it all adds to my knowledge.

@Neven - No problem, I only raised it in case it was a symptom of a wider issue.

<edit> 16. Seems to be OK now.

36
Arctic sea ice / Re: The 2016/2017 freezing season
« on: March 05, 2017, 08:26:23 AM »
Oops. Just realised there is a separate thread on PIOMAS updates. March starts on p27.

BTW has the post count stopped working? I'm not bothered, but have been stuck on 15 for the last 3 posts.

37
Arctic sea ice / Re: The 2016/2017 freezing season
« on: March 05, 2017, 08:11:16 AM »
PIOMAS data for Feb has been released, and it's not good news.

"Arctic sea ice volume continues 2017 with a another new record low. February 2017 sea ice  volume was 17,400 km3 , nearly 2000 km3 below the previous record from  February in 2013"

The gap from Feb 17 to the next lowest Feb volume is significant, about the same as the spread of all recorded volumes from 2010 to 2016.

38
Arctic sea ice / Re: The 2016/2017 freezing season
« on: March 02, 2017, 06:55:14 AM »
As more images become available as the sun comes up I’ve been watching Parry channel, a possible exit route for MYI accumulated on the N coast of the CAA islands.

I can see movement in the ice there.

Thinking of the bigger picture. Prevailing wind is from the NE which will not assist clearing Perry ice into Baffin bay, but how about ocean current? We know there is a southward drift of ice from the CAB to the CAA driven partly by wind, partly by current.

Other than the narrow Fury and Hecla strait between Baffin I and the mainland the only way out is via Parry past capes Sherard and Liverpool into Baffin bay.

So current will prevail in moving ice South  Eastward down Parry  if the grain size of broken ice is small enough?
<edit - .gif seems not to be working>

39
Arctic sea ice / Re: The 2016/2017 freezing season
« on: January 08, 2017, 05:46:38 AM »
PIOMAS figures for December have been published:

"December 2016 sea ice  volume was 11,200 km3 , nearly  1000 km3 below the previous record for December in 2012.   This record is in part the result of anomalously high temperatures throughout the Arctic for November and end of December"

"Average ice thickness in December  2016 over the PIOMAS  domain is the lowest on record "

40
Arctic sea ice / Re: The 2016/2017 freezing season
« on: December 24, 2016, 07:38:51 AM »
The extraordinary warmth in the arctic, specifically at a well known location - the North Pole and on a memorable date - Christmas Eve,  is featured among the Headlines on the BBC:

http://www.bbc.co.uk/news/science-environment-38417198

It also got a couple of lines in the headlines summary on the FtV TV "Breakfast" programme.


41
Arctic sea ice / Re: The 2016/2017 freezing season
« on: December 11, 2016, 10:35:23 PM »
Ekman transport and wave action mixing has been mentioned a lot recently.

My understanding is that Ekman pumping is where wave action causes an offshore surface current which in turn draws warmer saltier subsurface water up . So it’s effect on the CAB must be small, as it only apparent near the coasts.

Also wave action is an elliptical motion of the water on the surface with a second, third…n elliptical motion below, but the amount of motion drops off dramatically with depth.
So a 1m wave would only have a significant effect down to around 3m
A 10 m wave (much less frequent) would have the same effect much deeper.
But the cold less saline layer in the CAB is c. 50m deep, so only very rare large waves would have a mixing effect into the warmer layer.

So the ice is relatively safe from Ekman and surface wave mixing.
Or can anyone point to a ref which contradicts the above?


42
Arctic sea ice / Re: The 2016/2017 freezing season
« on: December 08, 2016, 05:49:54 PM »
PIOMAS data for November has been released.

2016 has broken from the pack by some margin


43
The rest / Re: Presidential poll for US citizens on the forum
« on: November 24, 2016, 08:50:56 AM »
From my side of the pond:

Looking at his body language and voice – the hesitancy, changes in pitch- in the last few days of the campaign, I concluded he did not want to win.
His preferred position is carping from the sidelines: “If I had been elected President I would have….”
Knowing full well those proposals were impractical.
Now he has won, so has to retreat or reverse on them, e.g. The Wall, AGW, Special Prosecutor for Clinton…
In the meantime he has caused a widespread reaction against “Rhetoric Trump” (e.g. Paris deal, increased public awareness of AGW) and has morphed into cold light of day “Realistic Trump”

There is hope yet

44
The rest / Re: Presidential poll for US citizens on the forum
« on: November 23, 2016, 05:42:00 AM »
@Buddy

Take heart.

Apart from his change in mind on AGW and likelihood of causing a trade war induced recession, reducing consumption worldwide, there are other positives he may not have intended:

http://www.bbc.co.uk/news/science-environment-38034165

45
The rest / Re: Presidential poll for US citizens on the forum
« on: November 09, 2016, 08:35:38 AM »
Positive spin on the Trump victory.

First let's get our head around basic economics:
Money is worth nothing, no one ever pays for anything

Money today is just Fiat money, no intrinsic value.  Central banks can create money out of thin air without doing any work or giving any items of value in exchange for it.
Purchasing an item involves exchanging money for goods, the money was exchanged for work earlier. The item purchased is a product of work.
At the basic level the purchase was an exchange of one person's work for many other people's work throughout the supply chain.
All consumption of goods consumes energy, of services too because the service provider’s earnings allow them to consume in turn.

Trump is likely to go protectionist. The markets’ opinion, where there stock values reflect expected future profits, is that there is going to be less work in the world.

Without knowing it, Trump has taken a major step towards reducing consumption and therefore carbon emissions.

46
Arctic sea ice / Re: The 2016 melting season
« on: September 04, 2016, 08:25:29 AM »
I note there is no option to attach a sound file to posts, but I think Siegfried's funeral march may be an appropriate accompaniment for this one.
Bremen does not display North of 89deg. Taking the grey areas as cloud, it looks like <50% ice to me between 120 and 150E:

47
Arctic sea ice / Re: The 2016 melting season
« on: September 04, 2016, 07:47:41 AM »
North of CAA 27 Aug:

48
Arctic sea ice / Re: The 2016 melting season
« on: September 04, 2016, 07:42:45 AM »
A bit wobbly for my 1st animated GIF but movement can be clearly seen.
Larger floes can be seen breaking up during transit.
North of the CAA the ice is fragmented with a small enough grain size to fit through.
26 Aug to 3 Sept:

49
Arctic sea ice / Re: The 2016 melting season
« on: September 04, 2016, 07:31:33 AM »
Jaxa reports 2016 at 4.05 M km^2 in 2nd place below the 2007 extent of 4.07 M km^2

50
Arctic sea ice / Re: The 2016 melting season
« on: September 03, 2016, 07:14:23 AM »
China has ratified the Paris climate agreement.

In the nick of time too. Jaxa reports Arctic SIE of 4.09m km^2, a whisker above the 2007 minimum of 4.07 M km^2

Meanwhile there is still active weather causing CAA export, expected to continue for the next 24 hrs.  It can be seen on the Bremen map. On Worldview the area is mostly obscured by cloud, but I have seen movement southward there through the various sounds/channels during late August.

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