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Author Topic: Home brew AMSR2 extent & area calculation  (Read 1402916 times)

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1850 on: March 16, 2016, 03:16:35 PM »
The "torch" is on along the ice edge in the North Atlantic. Although the contrast has been enhanced, thus exaggerating the effect, the area figures have taken a hit because of this.

Click to start the animation.

Shared Humanity

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Re: Home brew AMSR2 extent & area calculation
« Reply #1851 on: March 16, 2016, 05:17:22 PM »
That looks horrible!

 :o
« Last Edit: March 17, 2016, 01:44:49 AM by Shared Humanity »

jdallen

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Re: Home brew AMSR2 extent & area calculation
« Reply #1852 on: March 16, 2016, 08:28:02 PM »
That loos horrible!

 :o
Mostly wind-driven, I think.  Temperatures over most of the area aren't really warm; most of the region the area shown is between -10 and -20C.  There may be melt at the edges of the Barents and around Svalbard, which is where there appears to be major up-welling of warmer water from the North Atlantic Drift/Norwegian current, but that's been true all winter.

Those temperatures are not particularly *cold* either, which this time of year is not good for the run up to the solstice.

We are still 3-4 weeks away from the point at which increased insolation will start making itself felt.  Until then, the lion's of what we see in numbers changes in either direction will be a function of wind driven compaction or dispersion.  Even after that, there will be multiple weeks of lag as the heat accumulates to sufficient levels to permit active melting.


[edit] Adding an image for SST's from NOAA.  I think it is worth noting that all across the region, they are above normal, someplaces remarkably so.  However, it's not the areas outside of the pack that concern me - it's the areas *inside* that are 0.25-0.5C warmer than normal.  That means movement - and associated ekman pumping - may bring a lot of heat to bear on the ice a lot earlier.

There may be a giant lurking under the ice, waiting for the right moment to reveal himself.
« Last Edit: March 16, 2016, 08:40:09 PM by jdallen »
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Neven

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Re: Home brew AMSR2 extent & area calculation
« Reply #1853 on: March 16, 2016, 08:52:14 PM »
I thought I was seeing some openings south of Novaya Zemlya through the clouds on LANCE-MODIS today. Interesting.
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werther

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Re: Home brew AMSR2 extent & area calculation
« Reply #1854 on: March 16, 2016, 10:11:51 PM »
JDAllen, hi,

Some information has given me reason to suggest there’s more to this 220K km2 open water N of Svalbard and Frantsa Yosefa than the vagaries of wind:





These maps are just about the last four days, but a comparable map can be taken from the data for the whole winter period.
They indicate mean air temps between -3 and -8dC, up to 16dC(!) higher than usual. The same goes for Surface Skin/sea surface temp, which is hardly enough to prevent young ice from melting. At some depth (1-2 m) conditions might sustain bottom melt. New ice formation is almost impossible out there.
As suggested by ECMWF/Climate Reanalyzer, a temporary flux of colder air from the East might delay the start of the melt season out here. But, where’s the deepfreeze to really make a dent?

werther

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Re: Home brew AMSR2 extent & area calculation
« Reply #1855 on: March 16, 2016, 10:20:50 PM »
BTW, here's the forecast Northeast flux:



In former winters this could have had big impact. Not so much anymore. It won't matter much. What's left of cold will spread to waste into NE Europe (and Quebec).

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1856 on: March 20, 2016, 08:49:48 AM »
Astronomical spring starts over the East Siberian and Laptev seas with a loud crack.

click to start the animation.

Neven

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Re: Home brew AMSR2 extent & area calculation
« Reply #1857 on: March 20, 2016, 09:48:54 AM »
No wonder, given this 1053 hPa monster:
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Re: Home brew AMSR2 extent & area calculation
« Reply #1858 on: March 20, 2016, 11:01:48 AM »
Neven: my first impression yesterday was that the DMI pic was a glitch but I soon realized it was real... However, the cracks in Laptev may be good news as the leads will refreeze quite quick.

In additon, ECMWFs most recent run suggest that we'll see a pattern change by the end of March with more cyclones moving into the Arctic. Interestingly, it seems like the Arctic also is cooling now.....  :o A little late IMO.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1859 on: March 20, 2016, 04:46:11 PM »
Neven: my first impression yesterday was that the DMI pic was a glitch but I soon realized it was real... However, the cracks in Laptev may be good news as the leads will refreeze quite quick.

In additon, ECMWFs most recent run suggest that we'll see a pattern change by the end of March with more cyclones moving into the Arctic. Interestingly, it seems like the Arctic also is cooling now.....  :o A little late IMO.
Unfortunately LMV, the optimism about lead refreeze is a bit of whistling in the dark I'm afraid.

At this juncture, we are unlikely to get 45 days of conditions sufficient for freezing, and that's probably generous.  Further, even with temperatures cold enough to get freezing, it will not be cold enough to get the ice thickened past 0.3 - 0.5M, again at best.

So, absolutely, too little, too late.

I will add, the monster of a high pressure system over the Western Arctic/Beaufort is terminal news for the MYI poised just north of Svalbard and the Fram.  Export will be high and we will almost no doubt lose more volume to export than we gain in lead refreeze.
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Re: Home brew AMSR2 extent & area calculation
« Reply #1860 on: March 20, 2016, 06:50:56 PM »
Neven: my first impression yesterday was that the DMI pic was a glitch but I soon realized it was real... However, the cracks in Laptev may be good news as the leads will refreeze quite quick.

In additon, ECMWFs most recent run suggest that we'll see a pattern change by the end of March with more cyclones moving into the Arctic. Interestingly, it seems like the Arctic also is cooling now.....  :o A little late IMO.

Storms may be good news for ice, not too late, maybe not too little.
Below imb buoy 2013F snow profile in red, there is that jump of 20 to 30 cm of snow in April 2014 putting it on 80 cm. Remember how protective snow was to Beaufort and CAB in 2014.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1861 on: March 20, 2016, 06:55:07 PM »
Neven: my first impression yesterday was that the DMI pic was a glitch but I soon realized it was real... However, the cracks in Laptev may be good news as the leads will refreeze quite quick.

In additon, ECMWFs most recent run suggest that we'll see a pattern change by the end of March with more cyclones moving into the Arctic. Interestingly, it seems like the Arctic also is cooling now.....  :o A little late IMO.
Storms may be good news for ice, not too late, maybe not too little.
Below imb buoy 2013F snow profile in red, there is that jump of 20 to 30 cm of snow in April 2014 putting it on 80 cm. Remember how protective snow was to Beaufort and CAB in 2014.
I'd be more optimistic if we were talking about snow on old ice rather than leads.  Snow will do very little good there.

Also, the dominant weather feature appears to be the high pressure system - which with colder air will not be conducive for producing snow.

We'll see how it plays out over the next few weeks.
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epiphyte

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Re: Home brew AMSR2 extent & area calculation
« Reply #1862 on: March 20, 2016, 07:21:20 PM »

I'd be more optimistic if we were talking about snow on old ice rather than leads.  Snow will do very little good there.

Also, the dominant weather feature appears to be the high pressure system - which with colder air will not be conducive for producing snow.

We'll see how it plays out over the next few weeks.

Right. Right now if it did happen to snow on top of very thin ice, all it would do is stop it from getting thicker. Then there's only the snow left to melt.

A couple of years ago people may recall that I posted an image sequence of an apparently huge ice floe disappearing in one day. I've speculated that one way this could happen starts with the above scenario - a large area of thin ice covered by snow. If the the ice fractures the snow is heavy enough to sink it, which floods the snow with seawater. Poof.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1863 on: March 20, 2016, 07:48:15 PM »

I'd be more optimistic if we were talking about snow on old ice rather than leads.  Snow will do very little good there.

Also, the dominant weather feature appears to be the high pressure system - which with colder air will not be conducive for producing snow.

We'll see how it plays out over the next few weeks.

Right. Right now if it did happen to snow on top of very thin ice, all it would do is stop it from getting thicker. Then there's only the snow left to melt.

A couple of years ago people may recall that I posted an image sequence of an apparently huge ice floe disappearing in one day. I've speculated that one way this could happen starts with the above scenario - a large area of thin ice covered by snow. If the the ice fractures the snow is heavy enough to sink it, which floods the snow with seawater. Poof.
There is plenty of thick ice yet, more than cracks or FMI (first month ice). All I say: as overestimated is the effect of snow as insulator if it is not deep enough (less than 50 cm)  underestimated is its effect on delaying melting because of its albedo and because it melts at 0 C, not -1.8 C as FYI.  Even 10 cm of snow. I think we have been witnessing that from the cams every Summer (me since 2013 only).

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1864 on: March 21, 2016, 09:32:09 AM »
In the Hudson Bay, ice is moving and showing signs of "torching". Not unlike last year though.

(start the animation with a click)

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1865 on: March 22, 2016, 08:55:57 AM »
Ice edge is expanding in the northern Atlantic section.

To start animation, you "click".

Andreas T

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Re: Home brew AMSR2 extent & area calculation
« Reply #1866 on: March 22, 2016, 10:23:48 PM »
seeing how quickly that ice between Svalbard and Franz Josefs Land appears makes me think that there was some there already on the 11th. Suomi Bands M3-I3-M11 catches a glimpse of it.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1867 on: March 25, 2016, 10:09:09 AM »
The blackening of the fast ice in the Laptev Sea has begun, a few days later than last year.

Animation starts after your click.
« Last Edit: March 25, 2016, 10:19:58 AM by Wipneus »

Andreas T

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Re: Home brew AMSR2 extent & area calculation
« Reply #1868 on: March 25, 2016, 11:48:00 AM »
weather observations from Tiksi http://www.weatheronline.co.uk/weather/maps/city?LANG=en&WMO=21824&ART=MXMN&CONT=asie&R=150&LEVEL=150&REGION=0028&LAND=__&NOREGION=1&MOD=&TMX=&TMN=&SON=&PRE=&MONAT=&OFFS=&SORT=&MM=03&YY=2016&WEEK=100 on the southern corner of the Lena delta show warming on the 24th with possibly some rain wetting the snow (precipitation combined with dip in snow height)
« Last Edit: March 25, 2016, 11:58:42 AM by Andreas T »

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1869 on: March 27, 2016, 10:53:26 AM »
Ice racing to the Fram Strait. Greenland Sea sea ice extent (and area) are among the lowest for the time of year.

Animation will start after a click.

Skier

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Re: Home brew AMSR2 extent & area calculation
« Reply #1870 on: March 31, 2016, 07:22:06 AM »
Neven: my first impression yesterday was that the DMI pic was a glitch but I soon realized it was real... However, the cracks in Laptev may be good news as the leads will refreeze quite quick.

In additon, ECMWFs most recent run suggest that we'll see a pattern change by the end of March with more cyclones moving into the Arctic. Interestingly, it seems like the Arctic also is cooling now.....  :o A little late IMO.
Unfortunately LMV, the optimism about lead refreeze is a bit of whistling in the dark I'm afraid.

At this juncture, we are unlikely to get 45 days of conditions sufficient for freezing, and that's probably generous.  Further, even with temperatures cold enough to get freezing, it will not be cold enough to get the ice thickened past 0.3 - 0.5M, again at best.

So, absolutely, too little, too late.

I will add, the monster of a high pressure system over the Western Arctic/Beaufort is terminal news for the MYI poised just north of Svalbard and the Fram.  Export will be high and we will almost no doubt lose more volume to export than we gain in lead refreeze.


News Flash:  Arctic sea ice has grown a lot since your post, reaching a season high at day 88 at 12.92136 million km2.  That's an increase of over 200,000 km2 since your bold statement.  I think prudence dictates not making unsound statements or predictions.

Skier

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Re: Home brew AMSR2 extent & area calculation
« Reply #1871 on: March 31, 2016, 07:26:10 AM »
BTW, here's the forecast Northeast flux:



In former winters this could have had big impact. Not so much anymore. It won't matter much. What's left of cold will spread to waste into NE Europe (and Quebec).

Just an opinion, but every year the colored temperature charts seem to get redder and darker red, as if there is sweltering temperatures at the north pole.  In fact, we'd all freeze to death out there.  Hell, I froze to death just the other day skiing in spring. 

I realize your chart is a pressure chart, but your selection of red coincides with the heat charts and is a bit much.

jdallen

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Re: Home brew AMSR2 extent & area calculation
« Reply #1872 on: March 31, 2016, 07:32:34 AM »
Neven: my first impression yesterday was that the DMI pic was a glitch but I soon realized it was real... However, the cracks in Laptev may be good news as the leads will refreeze quite quick.

In additon, ECMWFs most recent run suggest that we'll see a pattern change by the end of March with more cyclones moving into the Arctic. Interestingly, it seems like the Arctic also is cooling now.....  :o A little late IMO.
Unfortunately LMV, the optimism about lead refreeze is a bit of whistling in the dark I'm afraid.

At this juncture, we are unlikely to get 45 days of conditions sufficient for freezing, and that's probably generous.  Further, even with temperatures cold enough to get freezing, it will not be cold enough to get the ice thickened past 0.3 - 0.5M, again at best.

So, absolutely, too little, too late.

I will add, the monster of a high pressure system over the Western Arctic/Beaufort is terminal news for the MYI poised just north of Svalbard and the Fram.  Export will be high and we will almost no doubt lose more volume to export than we gain in lead refreeze.


News Flash:  Arctic sea ice has grown a lot since your post, reaching a season high at day 88 at 12.92136 million km2.  That's an increase of over 200,000 km2 since your bold statement.  I think prudence dictates not making unsound statements or predictions.

<smiles broadly> Are you trying to troll me, Skier?  You *do* recall just how much lower that number is than the 1980-2010 average, yes?

But never mind that... my concern here was over ice thickness and *volume*, not area, nor extent.  Cold temperatures much higher than necessary to build volume can create thin ice over wide areas, but it won't replace MYI, nor will the new ice survive long when the melt season starts in earnest.  Unsound statements?  Bah.  I will trust the other experienced posters here to correct me when I make mistakes, which they do happily, and I accept gladly.  I find your particular criticism here lacking in both merit and relevance.
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epiphyte

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Re: Home brew AMSR2 extent & area calculation
« Reply #1873 on: March 31, 2016, 09:35:34 AM »

Just an opinion, but every year the colored temperature charts seem to get redder and darker red, as if there is sweltering temperatures at the north pole.  In fact, we'd all freeze to death out there.  Hell, I froze to death just the other day skiing in spring. 

I realize your chart is a pressure chart, but your selection of red coincides with the heat charts and is a bit much.

Yes, it is undeniably cold at the North pole in winter. But you know what? when I moved to Minnesota 25 years ago, it was cold here in the winter too. Now? Not as much. If it ever gets to the point where in winter you *wouldn't* freeze to death at the North Pole, the world as a whole will be very different from the way it is now.

Jim Hunt

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Re: Home brew AMSR2 extent & area calculation
« Reply #1874 on: March 31, 2016, 12:03:44 PM »
News Flash:  Arctic sea ice has grown a lot since your post, reaching a season high at day 88 at 12.92136 million km2.  That's an increase of over 200,000 km2 since your bold statement.  I think prudence dictates not making unsound statements or predictions.

Shock News!

http://forum.arctic-sea-ice.net/index.php/topic,1457.msg72693.html#msg72693

Prudence dictates a bold statement that those "over 200,000 km2" and more will disappear from the official figures over the next two days.

P.S. I note from elsewhere that you are already aware of this. As Friv might well put it:

Quote
The only sure thing is you are trolling us.

Please desist.
« Last Edit: March 31, 2016, 12:16:04 PM by Jim Hunt »
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magnamentis

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Re: Home brew AMSR2 extent & area calculation
« Reply #1875 on: March 31, 2016, 06:17:37 PM »
unfortunately we are gonna see more frustrated deniers who come here to vent off "sigh"

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Re: Home brew AMSR2 extent & area calculation
« Reply #1876 on: March 31, 2016, 08:34:33 PM »

...I realize your chart is a pressure chart, but your selection of red coincides with the heat charts and is a bit much.

Just struck me... Sometimes, it requires an act of will not to mock people.
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ghoti

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Re: Home brew AMSR2 extent & area calculation
« Reply #1877 on: March 31, 2016, 08:43:34 PM »
Must be something about spring. A senior Conservative party of Canada MP running for the party leadership also chimed in today with denier tweets.

Neven

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Re: Home brew AMSR2 extent & area calculation
« Reply #1878 on: March 31, 2016, 10:42:37 PM »
For the sake of transparency, I'd like to announce that I've banned Skier with the accompanying text:

Quote
Skier, it was fun while it lasted, but I don't think your contributions will be a contribution to interesting discussions in a friendly atmosphere. While I was reading your comments too many flags went up because of references to worn-out climate risk denier mythinformation (global sea ice, vikings, etc). Good luck with finding another forum, or maybe try WUWT.

Best,

Neven
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plinius

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Re: Home brew AMSR2 extent & area calculation
« Reply #1879 on: April 01, 2016, 01:00:42 AM »
Well, he " froze to death just the other day skiing in spring", as he said.

I heard this does horrific damage to nerve cells, so we should have faced him with more misericordia in our hearts!

seaicesailor

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Re: Home brew AMSR2 extent & area calculation
« Reply #1880 on: April 01, 2016, 01:33:22 AM »
If one accepts that over the years, spread of ice extent in April-May and November-December is relatively small (for whatever reasons), and that ice fails to extend as much in Winter as NH becomes warmer, a flatter shape of the curve seems consequential in future years.

I guess it is not that transcendental for the time being, anyway, except if one is obsessed on the exact date of the maximum. A discussion nevertheless confined within the brief interim between freezing and melting seasons.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1881 on: April 01, 2016, 05:10:00 AM »
Is it possible to measure the flatness of the freezing curve? Something like #days within 1% of the max?

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Re: Home brew AMSR2 extent & area calculation
« Reply #1882 on: April 01, 2016, 06:22:13 AM »
unfortunately we are gonna see more frustrated deniers who come here to vent off "sigh"

I know it's annoying but it's a good sign.  it means more people are visiting this forum specifically andthat more people are watching the arctic in general.  it also means deniers view this forum as a threat to their interests.

I think polite deniers should be allowed to stay, because when they engage our senior members in debate it's obvious who understands the real science.  this creates an opportunity to debunk fallacies for newbie lurkers who find their way here.  that guy was a jerk, and he deserved to be banned because he was rude.  but seriously, he was annoying but not a threat.  he wants to  complain about a pressure chart because temperature charts are getting hotter?  I wish heHAD been nice, I would have thoroughly enjoyed watching him attempt to debate you guys.  even I could have found a temperature line graph for him and posted it in black and white. 

NOT that I'm asking any specific persons to do the extra work, I know you are busy with the real science :)



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Re: Home brew AMSR2 extent & area calculation
« Reply #1883 on: April 01, 2016, 10:56:32 AM »
On other sites I visit this forum is held in high regard ....... even if the resident deniers ( do you find them becoming more and more Judith curry over time???) refuse to visit because of its 'warmist agenda????????' I know what that reluctance feels like as I have to be dragged, kicking and screaming, to WUWT these days in case I glimpse the comments section..........

The sad thing is that whilst that thin white skim remains they can sing their 'nothing much changes' song and point at extent/area as proof ( odd their other measure of choice in 2013 and 2014 stopped being used as pseudo proof in Jan?)

I am reassured that our home grown experts have nothing to 'fear' from such intrusions as skier represents. A little shakedown of the facts seems to do the trick?
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oren

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Re: Home brew AMSR2 extent & area calculation
« Reply #1884 on: April 01, 2016, 11:31:59 AM »
For the sake of transparency, I'd like to announce that I've banned Skier with the accompanying text:

Quote
Skier, it was fun while it lasted, but I don't think your contributions will be a contribution to interesting discussions in a friendly atmosphere. While I was reading your comments too many flags went up because of references to worn-out climate risk denier mythinformation (global sea ice, vikings, etc). Good luck with finding another forum, or maybe try WUWT.

Best,

Neven

Thanks Neven. My troll alarms went off as his posts progressed from innocent questioning to incessant bugging.

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Re: Home brew AMSR2 extent & area calculation
« Reply #1885 on: April 16, 2016, 10:00:18 PM »
Hi Wipneus,

Am I correct in presuming that your NSIDC based extent and area data is using NSIDC 0081 for the most recent data?

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1886 on: April 18, 2016, 08:51:36 AM »
Yes, the recent (nrt or near real time) data is calculated from the 0081 data set. It currently starts at the first of January 2015 like NSIDC's sea ice index does. When the final data is released for 2015 the series will probably start in 2016.

A note on the older ("final") data: NSIDC replaced the concentration data (the 0051 dataset) by a new version V1.1. That data runs to 2015-5-31. Quite a lot of changes especially in the beginning of the series. Their extent data is still based on the older version, while my extent and area data are based on the newer concentration data.

ChrisReynolds

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Re: Home brew AMSR2 extent & area calculation
« Reply #1887 on: April 18, 2016, 08:53:10 PM »
Thanks Wipneus,

I just wanted to get things sorted in my head regards the recent satellite failure. I think I'm going to break off using your gridded based rework of NSIDC extent until they start to publish the Sea Ice Index again.

I am chatting with Dr Zhang about the situation. I've asked whether the early May release of April PIOMAS data will be affected / delayed. I will post the reply on your PIOMAS thread when I get it.

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1888 on: April 21, 2016, 08:10:59 AM »
The Beaufort Gyre as seen by the AMSR2 satellite. I notice a little black spot, on a line between Barrow and Wrangel Island, that is strangely permanent in the moving ice masses.  Looking back it also appeared on previous Beaufort animations posted here.

« Last Edit: April 21, 2016, 08:40:10 AM by Wipneus »

southseas

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Re: Home brew AMSR2 extent & area calculation
« Reply #1889 on: April 21, 2016, 09:13:37 AM »
As a very long term lurker I thought ... here's a chance to delurk and actually say something useful ...

So, I though that black spot must be a rock (even a submerged rock could create a 'bow wave' like that in a current (or gyre) so I had a look on the Navionics free web app

This may not work - http://webapp.navionics.com/?lang=en#@7&key=uyerLlmx%60%5D

 - until you install the web app from the home page here http://www.navionics.com/en

But ... no rock.

There are however 3 submerged buoys - but closer to Barrow than the black spot, but if they are something that Shell left behind ... and since they don't have a great record with things staying where they left them ...

But even so, probably not big enough to create that sizable disturbance

My next post will be useful

Promise!

(btw - very appreciative of those who do pot a heap of useful .. if alarming ... stuff. Hence the lurking)

Jim Hunt

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Re: Home brew AMSR2 extent & area calculation
« Reply #1890 on: April 21, 2016, 09:51:48 AM »
I notice a little black spot, on a line between Barrow and Wrangel Island, that is strangely permanent in the moving ice masses.

Might that be the location of the Hanna Shoal?

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

jdallen

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Re: Home brew AMSR2 extent & area calculation
« Reply #1891 on: April 21, 2016, 09:52:05 AM »
The Beaufort Gyre as seen by the AMSR2 satellite. I notice a little black spot, on a line between Barrow and Wrangel Island, that is strangely permanent in the moving ice masses.  Looking back it also appeared on previous Beaufort animations posted here.
It appears to correspond approximately to the location of Hanna shoal.

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jdallen

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Re: Home brew AMSR2 extent & area calculation
« Reply #1892 on: April 21, 2016, 09:52:55 AM »
I notice a little black spot, on a line between Barrow and Wrangel Island, that is strangely permanent in the moving ice masses.

Might that be the location of the Hanna Shoal?


Hah! Two minds, same thought.
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southseas

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Re: Home brew AMSR2 extent & area calculation
« Reply #1893 on: April 21, 2016, 10:05:45 AM »
'Shoal' is relative (compared to 3000 metres N of Barrow)

Still 40 metres deep on that direct line between Barrow and Wragel and no point source to explain the disturbance.

oren

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Re: Home brew AMSR2 extent & area calculation
« Reply #1894 on: April 21, 2016, 10:19:01 AM »
This forum is amazing.

Jim Hunt

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Re: Home brew AMSR2 extent & area calculation
« Reply #1895 on: April 21, 2016, 10:30:11 AM »
Hah! Two minds, same thought.

We must be psychic JD!

However traditionally Hanna Shoal is considered to be a place the warm currents do not reach, and where therefore sea ice lingers longer.

http://go.nasa.gov/1pjRLPO
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1896 on: April 21, 2016, 11:05:46 AM »
Yes it is (caused by) Hanna Shoal. Here is a Sentinel 2A image, the blue ice to the right looks already thicker. Although it has to be over 15m thick to be grounded here.

Click (perhaps twice) to see the full-sized  image.

doogi

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Re: Home brew AMSR2 extent & area calculation
« Reply #1897 on: April 21, 2016, 11:09:45 AM »
There are are some higher lying areas at appr.. lat 72 long162.

PD in the chart  stands for position doubtful which make me believe the area isn't´t properly charted and there might be perhaps a submerged rock in the area.

http://www.charts.noaa.gov/OnLineViewer/16003.shtml

http://seasources.net/PDF/ChartNo1.pdf

Wipneus

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Re: Home brew AMSR2 extent & area calculation
« Reply #1898 on: April 21, 2016, 11:11:45 AM »
And here an animation 17-20 April. Everything moves, except the indicated ice cover.

Click to start.

johnm33

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Re: Home brew AMSR2 extent & area calculation
« Reply #1899 on: April 21, 2016, 11:12:01 AM »
Anyone know where shell drilled? One possibility is the ice sinking due to methane bubbles.