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slow wing

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Re: The 2015 melting season
« Reply #550 on: April 17, 2015, 07:05:48 AM »
On a more positive note: crandles and others, I've solved the temperature vs anomalies dilemma on the new ASIG Forecasts page! I've made a second, identical Forecasts page with the actual SATs, and via small links you can switch between actual temps and temp anomalies.

Pretty elegant solution, if I say so myself. Must be because I spent time with actual scientists at AGU today.  ;)

Nice  :)
That page is awesome! Thanks, Neven.

EDIT: the whole site is awesome actually! You've done a lot of work on it since a few months ago?

Wipneus

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Re: The 2015 melting season
« Reply #551 on: April 17, 2015, 07:50:45 AM »
As a mini project I am analyzing the AMSR2 thickness images ( available  in the sea ice monitor https://ads.nipr.ac.jp/vishop/vishop-monitor.html).

Here is an image (dated April 11) with the segmented color scale converted to linear grey scale and rotated to the usual orientation. Note that the melting area's are zero'd out.

Still to do: proper area calculation for the projection the images are using.

BenB

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Re: The 2015 melting season
« Reply #552 on: April 17, 2015, 09:56:04 AM »
Temperatures are getting interesting up north:

http://ocean.dmi.dk/arctic/meant80n.uk.php

According to DMI, we haven't seen those kinds of temperatures at this time of year for quite a few years (if ever), and overall the last month or so also appears to be one of the warmest on record.

Peter Ellis

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Re: The 2015 melting season
« Reply #553 on: April 17, 2015, 10:14:33 AM »
As a mini project I am analyzing the AMSR2 thickness images ( available  in the sea ice monitor https://ads.nipr.ac.jp/vishop/vishop-monitor.html).

Here is an image (dated April 11) with the segmented color scale converted to linear grey scale and rotated to the usual orientation. Note that the melting area's are zero'd out.

Still to do: proper area calculation for the projection the images are using.

Yeah, been looking at those.  Something's odd though - because while you can clearly see the multi-year ice advected into the Beaufort, it's actually being scored as thinner than the first-year ice.  That can't be right, so I suspect the sensor is picking up a mixture of actual thickness and other characteristics that make the MYI stand out.

I suspect it might be possible to process them to get an estimate of MYI percentage to compare with the Maslanik model graphs the NSIDC puts up - you'd need to do some funky edge detection stuff to pick out the patterns and score each pixel as MYI or FYI.

Neven

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Re: The 2015 melting season
« Reply #554 on: April 17, 2015, 11:11:23 AM »
That page is awesome! Thanks, Neven.

EDIT: the whole site is awesome actually! You've done a lot of work on it since a few months ago?

Thanks, slow wing. I update every few months, usually at the start of the melting season. The SLP patterns page was too much work (I figured Concentration maps is enough work already), which is why I've created the Forecasts page. I now only have to complete updating the Concentration maps page before the month is out, and then it's all set for the 2015 melting season.
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crandles

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Re: The 2015 melting season
« Reply #555 on: April 17, 2015, 12:19:51 PM »
That page is awesome! Thanks, Neven.

EDIT: the whole site is awesome actually! You've done a lot of work on it since a few months ago?

Absolutely.

So good, it seems naughty to ask if others would prefer the surface air temperature page to be SLP, temp anomaly and temp rather than SLP, Wind speed, Air Temp.

BornFromTheVoid

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Re: The 2015 melting season
« Reply #556 on: April 17, 2015, 12:39:55 PM »
Looking at this mornings latest model runs, it seems some average to slow melt conditions over the next 5 days, before a very strong signal for a -ve NAO appear, which would make things much more interesting.

While there are some mild pockets over the Arctic during the next few days, such as in the Barents/Kara sector now and Beaufort early next week, these aren't quite mild enough to cause dramatic melting yet. Meanwhile, northerly winds through the Bering Sea should keep the thin ice there from retreating rapidly, while other peripheral areas (Baffin Sea, Hudson Bay, Okhotsk) remain close to or below average temperature-wise, so nothing out of the ordinary for these regions.

After this point, from about 5 days out, both the ECM and GFS operational runs, as well as their respective ensemble means, begin to develop a strong -ve NAO pattern, which will increase the likelihood of Warm Air Advection (WAA) into the Arctic, massively increase export through Fram and produce more dramatic weather patterns overall.

By day 7, a powerful high pressure is centered over Greenland and a very -ve NAO is in place.

ECM operational t168


GFS operational t168


Note the tightly packed isobars around Fram (strong winds) and the flow of mild air into the Baffin sea and CAA. It appears that these aren't rogue runs, as the ensemble means of both are also in agreement

ECM ensemble mean


GFS ensemble mean



Anyway, if that strongly -ve NAO sets in things may get very interesting. Until then, not a whole lot expected to happen

Neven

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Re: The 2015 melting season
« Reply #557 on: April 17, 2015, 01:13:26 PM »
So good, it seems naughty to ask if others would prefer the surface air temperature page to be SLP, temp anomaly and temp rather than SLP, Wind speed, Air Temp.

Very naughty!  ;D

Wind speed is very useful because the SLP maps don't have isobars which makes it harder to infer wind speeds and thus transport potential, so that absolutely has to stay on.

I initially wanted to use a SLP map from Wetterzentrale or Meteociel like the one BFTV uses in the comment above, but it simply looks nicer if all the maps are from one source.

The only problem I had, was with the temp maps, because the anomaly maps make it look as if it's very hot somewhere, whereas it's still freezing. This becomes less problematic when actual temps go above zero, and anomalies actually do give a hint of where the heavy melting will take place.
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Neven

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Re: The 2015 melting season
« Reply #558 on: April 17, 2015, 01:15:24 PM »
Hmmm, I just had an idea. Maybe I should do the same thing for SLP and create a second forecasts page where you have a SLP map with isobars and numbers.

I'll have to sleep on this one...
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Rubikscube

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Re: The 2015 melting season
« Reply #559 on: April 17, 2015, 01:51:45 PM »
While there are some mild pockets over the Arctic during the next few days, such as in the Barents/Kara sector now and Beaufort early next week, these aren't quite mild enough to cause dramatic melting yet.

I, agree about that, but there seems to be some pretty strong winds setting up over beaufort in that 48h-144h period. Wouldn't be surprised to see significant polynyas opening up along the coast before -NAO is forecasted to appear. I do as well expect some significant snow melt in that part of the hemisphere, 7C and sprawling sunlight should be hitting as far north as Inuvik on Monday, thats a solid 12 degrees above the average high.

Yuha

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Re: The 2015 melting season
« Reply #560 on: April 17, 2015, 02:30:15 PM »
Hmmm, I just had an idea. Maybe I should do the same thing for SLP and create a second forecasts page where you have a SLP map with isobars and numbers.

I'll have to sleep on this one...

Other interesting ClimateReanalyzer maps are Precipitation&Clouds and Jetstream Wind Speed.
You could easily have six interesting maps per day either on two separate pages or on two rows on one page.

Anyway, don't lose any sleep on it.  ;D It's already great as it is. Thanks a lot on my part too.

Nightvid Cole

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Re: The 2015 melting season
« Reply #561 on: April 17, 2015, 02:44:43 PM »
DMI "north of 80" temps have shown a MONSTROUS spike upwards and are within 10 C of the melting point for 4/16!!!!

Neven

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Re: The 2015 melting season
« Reply #562 on: April 17, 2015, 02:58:33 PM »
Other interesting ClimateReanalyzer maps are Precipitation&Clouds and Jetstream Wind Speed.
You could easily have six interesting maps per day either on two separate pages or on two rows on one page.

Anyway, don't lose any sleep on it.  ;D It's already great as it is. Thanks a lot on my part too.

Jetstream is too difficult to interpret, and although I do have one Precip&Clouds image on the Daily graphs page, I'm not sure how trustworthy it is, and the distinction between cloud and ice isn't clear enough IMO.

But yeah, maybe I should make two pages.  ;D

It's good for now.

----

These are some serious cracks in the Beaufort I'm seeing:



The big cracking event in 2013 ultimately was good for the ice (at least, that's what I suspect), but that was two months earlier than now. It'll be interesting to see how this develops.
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Neven

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Re: The 2015 melting season
« Reply #563 on: April 17, 2015, 03:02:05 PM »
DMI "north of 80" temps have shown a MONSTROUS spike upwards and are within 10 C of the melting point for 4/16!!!!

DMI 80N temps plummeted below the average around day 125 in 2013 and 2014 and never really went back above it. We're day 107 now.
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Jim Hunt

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Re: The 2015 melting season
« Reply #564 on: April 17, 2015, 04:13:08 PM »
With a hat tip to Crandles, the latest from CryoSat 2:



Quote
Latest 28-day Sea Ice Thickness : 18/3/15 - 14/4/15

P.S. See also Neven's new blog post:

http://neven1.typepad.com/blog/2015/04/cryosat-sea-ice-thickness-maps.html
« Last Edit: April 18, 2015, 11:20:49 AM by Jim Hunt »
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Nick_Naylor

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Re: The 2015 melting season
« Reply #565 on: April 17, 2015, 06:08:24 PM »
March and 1Q2015 warmest on record - NOAA
The Pause that wasn't . . .

http://www.ncdc.noaa.gov/sotc/summary-info/global/2015/3

Timothy Astin

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Re: The 2015 melting season
« Reply #566 on: April 17, 2015, 06:54:03 PM »
Following coments on the DMI 80N temp graph ...

From the same data series, 2006 had a comparable early temperature rise, in both magnitude and date. I suppose we can expect a similar reversion of "above 80N temperature" back towards the mean over the next couple of weeks.

It strikes me it can be tempting not to maintain balance when noticing these short term excursions in data series.

There was comparable reaction to the JAXA ice extent data when it started an early downturn this year. Yet essentially it has reverted back close to the expected extent for the date since then.

The long and disastrous (for the planets ecosystem) march to an ice-free arctic is seen clearly in the data series averaged over a few years, and not in day to day data.

Mind you, I enjoy reading all the reports of short-term variations in the weather and predictions of weather effects reported here.


ktonine

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Re: The 2015 melting season
« Reply #567 on: April 18, 2015, 12:42:57 AM »
Following coments on the DMI 80N temp graph ...

From the same data series, 2006 had a comparable early temperature rise, in both magnitude and date. I suppose we can expect a similar reversion of "above 80N temperature" back towards the mean over the next couple of weeks.

Timothy, the DMI N80 temps will be closer to average in the ensuing weeks - but not because of any reversion to means.  They are approaching the  physical constraint of ice in water.  You'll note looking through the entire time series that temperatures become 'stuck' around 0 deg. C for weeks at a time in summer.  This is a physical constraint and is the reason DMI N80 temps really can't tell us much during the summer.

Timothy Astin

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Re: The 2015 melting season
« Reply #568 on: April 18, 2015, 10:18:49 AM »
ktonine,

In 2006 reversion to the mean took place in the range 260K to 265K, ie well below the summer temperature plateau caused by the ice/water state change.

Looking at multiple years data, the temperature plateau will be reached around day 150, not in the next couple of weeks.

So your correct observation about arctic summer temperatures seems a bit tangential to my comment.

Jim Hunt

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Re: The 2015 melting season
« Reply #569 on: April 18, 2015, 11:17:25 AM »
According to ice mass balance buoy 2015D the air temperature at the North Pole reached a high of -1.31 °C yesterday. It's on the way back down again now, but here's the effect that had on the temperature within the ice:
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Neven

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Re: The 2015 melting season
« Reply #570 on: April 18, 2015, 11:25:00 AM »
It strikes me it can be tempting not to maintain balance when noticing these short term excursions in data series.

Who isn't maintaining balance? Who is drawing conclusions from the DMI 80N temp spike (which is modelled anyway)?

It's just interesting to note and compare to previous years. Nothing more, nothing less.
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Neven

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Re: The 2015 melting season
« Reply #571 on: April 18, 2015, 11:03:02 PM »
Some red showing up around Svalbard:



Unfortunately DMI doesn't archive these images (at least, not for us), but here's the situation one month later last year:



And it looks like the southeastern Beaufort Sea (near the Mackenzie river estuary) is going to see above freezing temps in the coming week:



Again, the current situation in Beaufort as of yesterday:



It will be interesting to see what those temps and clear skies will do - if anything - to the cracked ice pack.

Here's that temp animation again, as Picasa made it smaller:
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epiphyte

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Re: The 2015 melting season
« Reply #572 on: April 19, 2015, 05:26:42 AM »
I've been watching the refreezing of the open water in the Beaufort, and subjectively it's doesn't look to be happening fast enough to gain any significant thickness before the summer sets in in earnest. Am I right in recalling that last year, the crackup came earlier and had a long time to refreeze afterwards?

One might speculate that timing could be everything in this new regime of relatively uniform, not so thick ice. Right now the cracks that have opened up in the past couple of weeks are likely covered in ice that could break up and disappear with not much provocation - leaving large areas with low albedo to soak up the sun just as it gets high in the sky. Or maybe not - if the cold returns for just long enough now, and then it snows half an inch, the whole Beaufort might still be an unbroken, high-albedo sheet in August - as it pretty much was last year.

...which IMO just goes to illustrate that the closer we get to the endgame, the less predictable things become. E.g. if the ice in the Beaufort had been just a little more fragile it might have broken up earlier and allowed a greater increase in volume toward the end of the winter.

In other words, nowadays less might conceivably end up being more, depending as always on the timing and the weather...

DavidR

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Re: The 2015 melting season
« Reply #573 on: April 19, 2015, 10:16:18 AM »
March and 1Q2015 warmest on record - NOAA
The Pause that wasn't . . .

http://www.ncdc.noaa.gov/sotc/summary-info/global/2015/3
Also worth noting that  the PDO index, has been above 2 for the past  4 months. This is only the fifth time this has happened in the 114 year record. Three of the four previous times it  occurred (1940, 1941 , 1997)  a global  temperature record was set, the fourth time occurred in 1993 just  after Mt  Pinatubo when global temperatures were suppressed.  The other years that  had 4 months with PDO above 2 were 1987, also  a record and 1936, where it  occurred in the second half of the year and was followed by a temperature record in 1937 and 1938.

The PDO  also appears to be a leading index with records and high temperatures following the high  readings, lending support to the view that this years temperature will be a big step up from the 2014 record. 

According to Joe Romm Apr-Mar 2015 has just broken the record for the hottest 12 contiguous months on record, breaking the record set in Feb, which broke the record set in January , which  followed the hottest calendar year.

Anyone looking for a quick bet on 2015 being hottest on record should get their bets in now. http://thinkprogress.org/climate/2015/04/15/3647177/nasa-hottest-start-year-record/
« Last Edit: April 19, 2015, 10:32:52 AM by DavidR »
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Peter Ellis

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Re: The 2015 melting season
« Reply #574 on: April 19, 2015, 09:05:29 PM »
According to ice mass balance buoy 2015D the air temperature at the North Pole reached a high of -1.31 °C yesterday. It's on the way back down again now, but here's the effect that had on the temperature within the ice:
Whoa, that's impressive - shows the impact of the thin snow cover.

Jim Hunt

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Re: The 2015 melting season
« Reply #575 on: April 20, 2015, 01:15:55 AM »
Ice mass balance buoy 2015C was installed just off Point Barrow on April 15th. After a quiet few days it suddenly moved 8 km yesterday.

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/winter-201415-imbs/#2015C

Google Maps seems to think it's run aground already! What's more Radarsat shows some multi-year ice in the vicinity at the moment.

You can see radar animations of the ice currently rushing past Barrow and last years breakup on April 29th here:

http://seaice.alaska.edu/gi/observatories/barrow_radar/recent-radar-animations
« Last Edit: April 20, 2015, 01:38:46 AM by Jim Hunt »
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Re: The 2015 melting season
« Reply #576 on: April 20, 2015, 01:28:04 AM »
Whoa, that's impressive - shows the impact of the thin snow cover.

Quite so. A significant decrease in the area above the curve in a brief period of time.

Air temperatures have headed back down now, so now let's see what effect a few days of more normal temperatures have, and whether (like last year) more snow falls before the melting season starts in earnest.
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Re: The 2015 melting season
« Reply #577 on: April 20, 2015, 10:01:24 AM »
Obouy #12 has finally melted most of the snow off the camera lens.



Interesting ice features there, would those jutting formations be from mechanical pressure as the ice formed?

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Re: The 2015 melting season
« Reply #578 on: April 20, 2015, 11:09:16 AM »
Interesting ice features there, would those jutting formations be from mechanical pressure as the ice formed?

Not exactly "as the ice formed". A modest pressure ridge formed in the midst of winter, I'd hazard a guess on January 6th, when the co-located ITP 84 stopped functioning properly. The buoy ought to be in the picture somewhere, but I can't spot it yet!
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Re: The 2015 melting season
« Reply #579 on: April 20, 2015, 01:51:32 PM »
According to 2015C's GPS it traveled 83.3 km in the general direction of the Bering Strait yesterday:
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slow wing

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Re: The 2015 melting season
« Reply #580 on: April 20, 2015, 02:34:40 PM »
Wow! That's averaging nearly 3-1/2 km/h.

 Do its sensors show it to still be on ice or is it just floating in the water?

EDIT: I clicked on the buoy link and it is still on ice. Must be a strong wind doing that then?

EDIT2: wait, what is going on with the sensors? On 16 April, sensor 5 and  higher appear to be in water. Four days later it looks like on ice down to sensor 20.

Explanation?
« Last Edit: April 20, 2015, 02:41:35 PM by slow wing »

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Re: The 2015 melting season
« Reply #581 on: April 20, 2015, 02:37:49 PM »
Do its sensors show it to still be on ice or is it just floating in the water?

It is most definitely still attached to ice, apparently still more than 2m thick though that's not obvious from the thermistors:

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slow wing

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Re: The 2015 melting season
« Reply #582 on: April 20, 2015, 02:42:48 PM »
But what about the readings 4 days earlier?

Maybe it was floating and has just been placed back on the ice???

EDIT:
How do you interpret that?

Maybe down to sensor 5 is snow and on 16th April the ice was all about ready to melt, in temperature equilibrium with the -2 degrees water, but then cooled by 20th April?

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Re: The 2015 melting season
« Reply #583 on: April 20, 2015, 02:50:03 PM »
What is going on with the sensors? On 16 April, sensor 5 and  higher appear to be in water. Four days later it looks like on ice down to sensor 20.

Explanation?

Immediately after installation the buoy was indeed sitting in water in the hole drilled for it. It is now firmly frozen into the ice, but I am wondering if its vertical position shifted somewhat before that happened.  It doesn't look like many of the thermistors are currently in the warming air above the floe.

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slow wing

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Re: The 2015 melting season
« Reply #584 on: April 20, 2015, 02:54:06 PM »
Ah, thanks, so it is newly installed. That might explain the temperature profiles.

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Re: The 2015 melting season
« Reply #585 on: April 20, 2015, 09:44:01 PM »
After a week of very slow melt, even record slow at times, it looks like things will turn interesting from mid-week onward.

The latest ECM shows the high pressure building around Greenland from Wednesday onward, quickly strengthening into a powerful >1050hPa anti-cyclone by the weekend.
This will bring several changes in airflow and melt trends across much of the Arctic. The first area to feel the effects, temperature-wise, is the Baffin sea region. Southwesterly winds and mild air should cause an acceleration in the melt there later this week and into the weekend, with surface air temps above 0C moving over the southern sea ice covered regions.









As the high pressure/-ve NAO becomes established and the clock-wise rotation around Greenland becomes stronger, to south westerly winds will begin to carry mild air over Hudson Bay and up into the CAA, with the >0C surface air temps spreading further inland. Meanwhile, northerly winds take hold over the Kara/Barents regions, like helping to spread the ice south and reduce melt rates.









Things stay largely the same after, but with high pressure attempting to ridge toward the Bering strait. Overall, we should see an increase in the Arctic-wide melt rate, but I doubt it will hit the extremes seen around this time in 2012. The reduced melt in the Barents/Kara region may offset some of the increased melt in the North American side. Should this set up continue on into May, the possibility of a more extreme melt phase increases.

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Re: The 2015 melting season
« Reply #586 on: April 20, 2015, 10:34:51 PM »
Indeed, BFTV, looks like Fram transport will accelerate quite a bit:
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Re: The 2015 melting season
« Reply #587 on: April 21, 2015, 09:57:11 AM »
Interesting I'd say



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Re: The 2015 melting season
« Reply #588 on: April 21, 2015, 11:38:52 AM »
A lead has opened up in sight of O-Buoy 11. ITP 85 and IMB 2014I are also visible in the picture:

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Glenn Tamblyn

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Re: The 2015 melting season
« Reply #589 on: April 21, 2015, 12:49:25 PM »
Anyone know what is happening in the CAB? Uni Bremen is showing a s$!t load of some sort of melt. Can that all be melt ponds? Artifact of some  sort of instrumentation issue?

Neven

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Re: The 2015 melting season
« Reply #590 on: April 21, 2015, 01:12:46 PM »
Glenn, we've been discussing it in Wipneus' AMSR-2 thread.

Wipneus: "No, this is not concentration dropping so quickly. However we have seen this more often in this time of year (last year it was spectacular in the Laptev region), so it will have to do something with the melting setting in."

Me: "UB SIC shows the wipe as well, although I'm usually wary of these changing colours (click to see the animation):"
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Neven

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Re: The 2015 melting season
« Reply #591 on: April 21, 2015, 01:14:36 PM »
Again,  I'm usually wary of these changing colours - especially during this early phase of the melting season - , but I have some extra interest in the North Pole this year.
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Jim Hunt

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Re: The 2015 melting season
« Reply #592 on: April 21, 2015, 01:22:09 PM »
Can that all be melt ponds? Artifact of some  sort of instrumentation issue?

It has been remarkably warm up there recently. Scroll back to:

http://forum.arctic-sea-ice.net/index.php/topic,1149.msg50079.html#msg50079

However I very much doubt it's melt ponds at this juncture, but given the persistence of the "anomaly" a mere "artifact" seems unlikely also. Bremen are using AMSR2 these days, but other sources don't show the same effect. Here's OSI-SAF for example:



Whilst there's been a modicum of speculation I don't think anyone's come up with a convincing physical explanation as yet. 

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JayW

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Re: The 2015 melting season
« Reply #593 on: April 21, 2015, 01:45:06 PM »
Could it be the effect of something like freezing rain?  If the surface got very close to freezing, seems plausible that liquid precip could have fallen from the warmer upper levels, and froze on contact. 

Admittedly, I haven't been watching the arctic weather, nor know if freezing rain is capable of causing such an effect.  Just a thought.
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Re: The 2015 melting season
« Reply #594 on: April 21, 2015, 01:56:41 PM »
Very interesting discussion. It would be nice if we can identify the source of this effect.

Another thought I had was does this correlate at all with cloud cover?

Jim Hunt

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Re: The 2015 melting season
« Reply #595 on: April 21, 2015, 02:57:15 PM »
Cryosphere Today still seems to be stuck on April 12th, but here's the NSIDC's SSMIS based concentration map from April 19th:
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seaicesailor

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Re: The 2015 melting season
« Reply #596 on: April 21, 2015, 04:21:03 PM »
At least, there is a small spot of concentration under 100% common in the four different sources. It is at latitude 85 °, from the Pole toward East Siberia.

Neven

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Re: The 2015 melting season
« Reply #597 on: April 21, 2015, 04:22:06 PM »
Like Carex says on Wipneus' AMSR2 thread, it could have to do with that low sitting there:
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johnm33

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Re: The 2015 melting season
« Reply #598 on: April 21, 2015, 04:33:59 PM »
Looking at http://earth.nullschool.net/#current/wind/surface/level/overlay=temp/orthographic=-0.48,86.69,1024 back to the 16th the wind to the right of the pole [taking wind direction as the meridian] accelerates the ice south, that to the left into the space created. Then the anti-cyclone kicks in and is close enough to the pole to accelerate all the ice south. So, my guess is that these are brief but frequent and rapidly freezing patches of open water.
edit  strikethrough duh :-[
« Last Edit: April 21, 2015, 09:06:25 PM by johnm33 »

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Re: The 2015 melting season
« Reply #599 on: April 21, 2015, 04:41:35 PM »
Very interesting discussion. It would be nice if we can identify the source of this effect.

Another thought I had was does this correlate at all with cloud cover?

Liquid water in clouds, as well as water vapor have an effect especially on ASI algorithm based sea ice concentration: Uni Bremen and Uni Hamburg are ASI based.

BUT, the effect goes the other way: clouds and water vapor always INcrease apparent concentration.

For clouds to do this, you must assume that somehow the compensation that is built in these computations is overcompensating. Without remembering the details of this calculation, I think this may be one of the more likely possibilities. It would mean that as soon as the atmospheric conditions are more stable, the torching will disappear.