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Messages - JayW

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Greenland and Arctic Circle / Re: The Nares Strait thread
« on: November 03, 2019, 11:16:21 AM »

Arctic sea ice / Re: The Rammb Slider Thread
« on: October 10, 2019, 11:49:24 AM »
Now that polar night is descending on the arctic, it's time to switch to band I04, shortwave IR discerns temperature.  I inverted the colors and enhanced the contrast, I think it will make for a good substitute for visible bands.  I find the low light band has issues with some form of "glare".

This is the area north of Svalbard at roughly 82.5°N,10°E, that has been discussed before, that "swirl" still evident.   The gif is short, fighting the clouds

Click to run, link to location.

Arctic sea ice / Re: The 2019 melting season
« on: August 26, 2019, 12:31:05 PM »
It seems to me that the stall these last few weeks compared to 2012 is mostly due to dispersion. Late August 2012 saw the inner ice a lot more compacted, especially towards the Pacific side.

Dispersion obviously causes higher extent, but then area seems to be stalling as well. But how reliable are the area measurements, particularly with highly dispersed ice under cloudy skies? I don't know.

But it does seem to me that a good "compaction event" on the Pacific side could lose several 100 k's without any extra melt.

And that leads me to wonder if the difference between 2012 and now lies not so much in how much ice has melted as in how it is distributed - admittedly, 2012 had less ice, but the difference probably wasn't nowhere as big as the current extent numbers indicate.

I agree.

72 hour loop. North of the Laptev.
Requires a click. I tried getting the file down as much as possible. Contrast boosted for detail.

Arctic sea ice / Re: The Rammb Slider Thread
« on: August 25, 2019, 03:27:07 PM »
 30.5 hour loop, NE Greenland.  375M approximately per pixel.
Click for animation.

Arctic sea ice / Re: The Rammb Slider Thread
« on: August 24, 2019, 11:43:15 PM »
Greenland sea 149 hours.

Arctic sea ice / Re: The Rammb Slider Thread
« on: August 13, 2019, 11:43:35 AM »
Mobile, isn't it?
Sure seems like it reacts quickly to winds, and it's marching towards the Atlantic, as it has for the most part.

Speaking of winds, they have turned southerly over the Laptev and points north, and should persist for some time.

Contrast boosted.

Arctic sea ice / Re: The Rammb Slider Thread
« on: August 11, 2019, 01:51:03 AM »
Glad that it was well received.

Clear skies around the pole today.
Needs click, contrast slightly enhanced for detail.

Arctic sea ice / Re: The Rammb Slider Thread
« on: August 04, 2019, 04:44:56 PM »

Yes, mine is shorter. rammb eats up my broadband volume. Thanks for the links. I definitely couldn't go searching for these.

Here's my effort to make RAMMB a bit more user friendly for those who have internet struggles with the demands of the slider.  I can add more upon request (including gifs if needed and as time allows), note that the "geocolor" and "natural color" appear the most resource intensive. 

I'm providing a list of links to locations around the arctic using band I2 (my favorite), with the minimum number of frames (6), and as a still image.  My hope is that this'll be gentler on this with metered/throttled/slower connections.

These are not the maximum zoom, but can be zoomed in once more.

North Pole lower left, 60°W-30°E

North Pole upper left, 150°W-60°W

North Pole upper right, 120°E-150°W

North Pole lower right, 120°E-30°E

Kara Sea south

Kara Sea north

Laptev Sea/Lena River delta

Laptev Sea North

East Siberian Sea west

East Siberian Sea east

East Siberian Sea north

Bering Sea

Chukchi Sea south

Chukchi Sea north

Beaufort Sea west

Beaufort Sea east

Beaufort Sea north

CAA - Amundsen Gulf/M'Clure Strait/Viscount Melville Sound

CAA - Prince of Wales Island/Resolute

CAA - Prince Gustav Adolph Sea/Byam Martin Channel/Peary Channel

Parry Channel east/Prince Regent inlet/Admiralty

Baffin Bay north

Baffin Bay south

Nares Strait/Lincoln Sea

Fram Strait/Greenland Sea


Franz Josef Land/Barents Sea

Greenland wide shot - band M8

Arctic sea ice / Re: The Rammb Slider Thread
« on: August 04, 2019, 03:12:01 PM »
The RAMMB slider is awesome. The public access is total.
I wish all science was like this.

I can't see you finding anything like slider anywhere else. Three satelliites in geostationary orbit giving you everything all the time.

  I agree with everything you said, and appreciate it.  I just wanted to clarify that the orbits are actually sun-synchronous. Each satellite makes 14 passes a day, taking roughly 102 minutes to complete an orbit.  The ~3,000km wide field of view allows each pass to image from roughly 68° to 5° on the far side of the pole, spanning 28°.  So above 85° is imaged every pass.
  I believe that the slider actually only incorporates two of them, SUOMI and JPSS-1, which orbit opposite each other, giving us 51 minute intervals.  SUOMI is actually beyond its planned 5 year expected lifespan, but more of these satellites are planned over the next decade.

Arctic sea ice / Re: The Rammb Slider Thread
« on: August 03, 2019, 01:02:41 AM »
A glimpse through the clouds gave a peak at the Prince Gustav Adolph Sea today.

Arctic sea ice / Re: The Rammb Slider Thread
« on: August 02, 2019, 04:03:43 AM »
Similar to the one discussed earlier off Svalbard.
Yep, that one is still making it's daily appearance as well.  I misspoke when I initially posted that one and said it was at 80°N , 5°E, I had the latitude line confused on the slider, it's actually 82.5°N, 5°E.

Arctic sea ice / Re: The Rammb Slider Thread
« on: August 02, 2019, 03:42:49 AM »
Wind/ cloud effects..

It's a 78 hour loop I posted, and the feature recurs at the same spot, at almost the same time 4 days in a row. That's why I believe it to be related to the tides, the one north of Svalbard also shows a daily rhythm.  I don't see how the clouds and winds would be exactly the same 4 days in a row.  It actually was there the day before that loop as well. 

It was also there in mid July, I think the higher tides surrounding the full/new moons enhances it.

Arctic sea ice / Re: The Rammb Slider Thread
« on: July 28, 2019, 02:04:11 AM »
Continuation from the gif in post #150.

I believe the resolution is about 375m /pixel.  I'd say the front moved about 70 pixels, equaling roughly 26km, over the 13.5 hour animation, so about 2km/hour is my guess.  Does it plow straight through? Make a hard left? Or stop in its tracks?. Won't know till tomorrow, and even then, who knows if it'll be clear.

Click it.

Greenland and Arctic Circle / Re: The Nares Strait thread
« on: July 27, 2019, 08:56:52 PM »
Stiff winds blowing down the Strait.

Arctic sea ice / Re: The Rammb Slider Thread
« on: July 27, 2019, 06:49:46 PM »
I think it might be both winds and melt water pushing in. To me, it looks like you can see sediment rich water moving west through the channel. 
Well the problem with meltwater is that I'm not at all sure that there could be enough of it to cause such a strong movement in a (presumably) deep fjord. But you are right, there is discoloration that follows the ice retreat, possibly just reflecting a change in temperature?

Meltwater would be brown, but the discoloration seems more bluish. Perhaps an extremly rapid spread of algae? I don't know.
Here is an interesting feature at about 80°N, 5°W.
Very interesting, with those circular movements. Is it the wind doing that, or ocean currents? This Rammb slider thing is really showing us details that I for one didn't know existed.

I don't believe high resolution hourly imagery has been available until they added it to the slider.

I thought of Peyto lake in Canada, and just thought it was fine sediment similar to that.

The swirl at 80°N,5°W looks oceanic to me, as it has appeared the last week or so in the same location at thr same time.  I can't tell how long is been there, as it was too cloudy to see before the 21st.

Arctic sea ice / Re: The 2019 melting season
« on: July 18, 2019, 11:17:36 AM »
Sincerest condolences Neven.

Re: GAC, I don't think one is a necessity, 5-7 days of persistent winds from the right direction could have a similar effect in my opinion.

Arctic sea ice / Re: The Rammb Slider Thread
« on: July 14, 2019, 11:37:48 AM »
 Appreciate your interest binntho, as b_lumenkraft mentioned there are likely several/many factors at play.  I'm certainly no expert, but the the counter clockwise motion to me suggests there is some upwelling.  I'm basing this on how the atmosphere works, low pressure is associated with rising air. 
  With so little open water, wind stresses seem to be minimal, but perhaps a southerly flow over the land masses of the CAA *could* result in modest coastal upwelling.
  The most mysterious question to me, is whether these exist under the ice, or do they form only due to the opening.  I haven't a clue.  It'll be interesting to see how they behave going forward.
   I think features like this emphasize the value of these sub daily images available from RAMMB, and am grateful that others, especially b_lumenkraft, have also taken an interest.

Arctic sea ice / Re: The 2019 melting season
« on: July 14, 2019, 11:23:18 AM »
17 hour loop centered at roughly 87.8° N, 68° W (I'm approximating here) lat,lon included with last image, latitude line is 87.5°N.  Contest slightly boosted for detail.  Looks like the CAB is forming some stretch marks.  A general motion towards the Atlantic is also seen.
Chick to run.

Arctic sea ice / Re: 2019 vs 2012
« on: July 13, 2019, 10:49:57 PM »
Pacific side comparison, July 12.
Chick to run

Arctic sea ice / Re: The Rammb Slider Thread
« on: July 13, 2019, 08:56:02 PM »
This shot is centered at roughly 84°N,110°W.  ~18 hours.  Contrast gently enhanced for detail.
A shear line can be seen bisecting the image horizontally.  There's also interesting patches of dark peppered on the left side.  This is band I2.  A general motion towards the Atlantic is also evident.

Click to run

Arctic sea ice / Re: The Rammb Slider Thread
« on: July 13, 2019, 04:41:43 PM »
Some eddies have formed in the crack of insignificance north of the CAA, and now that the high resolution I bands are updating regularly, we can see them in better detail.  Some flows can also be seen breaking up a bit as well.
Click to play.

Arctic sea ice / Re: The 2019 melting season
« on: July 10, 2019, 12:16:05 PM »
How common are thunderstorms around the Lena river?  Lena delta in the upper right.
Click to play

Arctic sea ice / Re: Arctic Ocean salinity, temperature and waves
« on: July 09, 2019, 01:08:32 PM »
106 hour loop, Chukchi sea, band M15 with colors inverted and increased contrast for detail.  It appears that some of the warmest waters are those that are pushing north, just east of Wrangel Island.

Arctic sea ice / Re: When will the Northwest Passage "open" in 2019?
« on: July 06, 2019, 10:10:01 PM »
100 hour loop,, Cornwallis island in the lower right corner.  The tides are doing some work. Pretty sunny as well.

Developers Corner / Re: Creating Animated GIFs
« on: July 06, 2019, 04:06:53 AM »

The how to is posted here,1259.msg211015.html#msg211015
Let's continue there so as not to disrupt this thread. Looking forward to the next test.

Here are three short gif around Peterman glacier if you want to give it another go, I figure the landcover there is quite varied, so perhaps something will be interesting.  I will work on learning imagej as time allows.  I tried to keep the files smaller, don't know how to package them in a more efficient manner.


Arctic sea ice / Re: The Rammb Slider Thread
« on: July 04, 2019, 10:17:08 PM »
create my own RGB composites
If you can provide 3gifs of the same size of exactly the same area with matching timestamps I would be interested to put them together for a test. I'm on metered broadband so I don't play with rammb much.

btw this area east of svalbard looks interesting and quite clear recently.
Worldview with bathymetry inlay
edit: aqua modis is better

Here are three. Appreciate your efforts!  ;D
I2 then M12  and M13,  I4 was missing too many frames so I had to use M12.  Depending on the output, I'll provide 3 of the Chukchi, as the arts in that area are interesting, and the skies might be clear for a bit.  I'll do some nearer the pole for snow/ice cover later.  All require a click, and I didn't optimize to preserve as much detail as possible.

Added the link just in case I want to revise the same exact view.

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 26, 2019, 12:28:03 PM »
Jaxa AMSR2 Arctic sea ice volume calculated by Wipneus

Arctic sea ice / Re: The 2019 melting season
« on: June 25, 2019, 11:47:15 AM »
As mentioned in the RAMMB slider thread, under clear skies, the shortwave IR bands I4, M12, and M13 are sensitive to surface temperatures and have the ability to detect sea surface temperatures.

Attached is a 32 hour loop (June 23, 16Z to 25, 4Z)  of the Laptev, with discharge from the Lena river seen spreading from the lower left corner.

Band I4 with band M13 50% overlay, this helps hide the clouds somewhat.  Contrast  enhanced and lightened for detail.

Arctic sea ice / Re: The 2019 melting season
« on: June 22, 2019, 05:26:54 PM »
Included is a 20 hour loop showing the impressive ridge.  As energy rotates around it, it will go through several anticyclonic wave breaks (evident already).  These often give numerical models difficulty.  As they "break" they generally result in a cyclone downstream, in this case the Beaufort/CAA region.   Again, very hard to predict, and should give anyone pause about buying model runs beyond hour 120, and temper expectations.  Just my two cents.  I'll go back to simple observations of interesting features.

Arctic sea ice / Re: The 2019 melting season
« on: June 22, 2019, 08:17:47 AM »
Mouth of the Kolyma.  More cracks forming, more signs the immobile ESS ice will disintegrate shortly.

Arctic sea ice / Re: The 2019 melting season
« on: June 22, 2019, 08:01:58 AM »
54 hour loop of the Laptev.  It's been pretty sunny there, a little burst of southerly winds today nudging the ice north.

Arctic sea ice / Re: The Rammb Slider Thread
« on: June 21, 2019, 12:39:42 PM »
The current east of Wrangel Island eating it's way into the pack.
60 hours.
Click to run

Arctic sea ice / Re: The Rammb Slider Thread
« on: June 20, 2019, 12:55:46 PM »
The shortwave IR bands M12 and I4 are sensitive to sea surface temperatures.  I had to boost the contrast and "lightness" in ezgif for better detail, I lack the processing skills others her have.  Sorry the shot land masses are a bit distracting.  Lighter is warmer.  Some frames weren't available, so there's a bit of a jump in there.

Bering Strait, needs a click.

Arctic sea ice / Re: The 2019 melting season
« on: June 20, 2019, 10:17:34 AM »
East Siberia.

Looks like the fast ice cracked here from the weight of the inland freshwater sitting on it.

I don't think the river is flowing onto the ice, I think it's completely melting it into open water, as the severed ice appears to be moving around freely.  More cracks are forming, feels like the ESS will really deteriorate very soon.

Arctic sea ice / Re: The 2019 melting season
« on: June 17, 2019, 12:52:36 PM »

P.S. does anyone know the meaning of the LIGHT blue line in the Slater graph? I have already asked previously in the 'stupid questions' thread and nobody answered there.

I'd love to be corrected if wrong, but my understanding is that the light blue line treats the ice anomaly as a whole, whereas Slater looks at each grid cell independently.  But I could be misunderstanding.

Unrelated, here is the last week in the Beaufort blender.

Requires a click

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 15, 2019, 07:53:41 PM »
Slater model suggests sea ice is moving from where it's hard to melt, to where it's easy to melt. 

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