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Messages - JayW

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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. 

Greenland and Arctic Circle / Re: Greenland 2019 Melt Season
« on: June 13, 2019, 08:56:41 PM »

What does the team make of the latest NWS ice map?

I think the winds made a good run at closing it back up, but fell short, at least so far.  The pack becoming more disperse is allowing the complex currents to reveal themselves.  I'd say a non icebreaker can still safely navigate, but others may have a different opinion on what's considered open.

Contrast boosted for detail

Arctic sea ice / Re: The Rammb Slider Thread
« on: June 13, 2019, 11:34:24 AM »

I don't know if it's surface temperature or snow wetness or a combination of both.

I did saw the ESS darkening in M8 and M10 band like 2 days before melt ponds became visible in Sentinel.

Also the Greenland darkening Jay posted, corresponds directly to rising temperatures.

I did a bit of poking around, trying to read stuff well above my pay grade.  This one paper explains a lot I think.  Ultimately, it appears we are likely looking at grain size.  Fresh snow generally falls as dendrites, the pretty, six sided geometric shapes we see portrayed in Christmas movies that's highly reflective.  Over time, the snow metamorphosizes due to factors such as temperature, humidity, compaction, etc.  It turns out that the 1240nm wavelength is sensitive to the grain size (larger grains better absorb this part of the spectrum).  Anyone who has watched a lot of snow melt will have likely noticed that as snow warms to the point of melting, it turns into "corn snow", large grainy snow that loosely resembles ball bearings (at least it reminds me of them). 

I believe that this must be what we are seeing, the metamorphosis from a more flake-like structure, to larger, coarser grains that occurs as a snowpack begins going through thaw-freeze cycles.  So while the sensor is picking up on the increased absorption of the 1240nm wavelength by larger grains, it coincides with the temperature rising above freezing, or any other process that would increase grain size like rain or even compaction.

Arctic sea ice / Re: The Rammb Slider Thread
« on: June 13, 2019, 03:52:09 AM »
Greenland, band M8.
Needs click

Arctic sea ice / Re: The 2019 melting season
« on: June 12, 2019, 08:58:26 AM »
The Laptev is going to take it on the chin.  Look at those closely packed isobars, latest euro continues the push towards the Atlantic with the 970s cyclone, while keeping the Siberian side toasty.  The Beaufort low might pump some warmth into the CAA as well, as it stirs up the Beaufort sea, trading surface melt for bottom. 

32 hour loop, the frontal passage and associated wind shift is quite evident, it also removes all doubt from my mind that it's clear sailing for a non-icebreaker.

18:22 UTC

Is it?

I think that front blew a path through the slush, but until all the clouds clear, can't be 100 percent positive.  There's a real chance the winds blow the pack back in, and I'm not sure if that would nullify any "open" path.   I'll let others decide.

Arctic sea ice / Re: The 2019 melting season
« on: June 09, 2019, 12:24:52 PM »
Some fast ice is beginning to pulled away in the ESS. (First attachment,  band I1 with I3 overlay.

Second attachment is the EURO ensemble 5 day average sea level pressure. It screams slow extent loss.  Winds have reversed int the Chukchi already, and an amazing ice edge is visible inch thr RAMMB slider.  We should also see ice getting dispersed in the Beaufort for the time being.  The one constant is the push towards the Atlantic.  The ESS and Laptev will see persistent southerlies, and likely the most impressive extent declines.
  This isn't to say melting will halt, in fact, is should transport ice to areas it could melt quicker.  It'll be interesting to watch the floes reaction in the Chukchi in particular.

10 hour loop

Arctic sea ice / Re: Latest PIOMAS update (May 2019)
« on: June 05, 2019, 12:15:55 AM »
May PIOMASS thickness distribution falls short of being encouraging.

Arctic sea ice / Re: The 2019 melting season
« on: June 03, 2019, 12:29:24 PM »
925 Vector wind anomaly for May.

yup.  kinda stalled out there (animates on click)
Worldview images from consecutive days can be as little as 51 minutes apart or a much as 47.5 hours apart, it depends on which orbital swath the image was taken from.

If you look at it with sub daily imagery, it marches along unabated.
13.5 hour loop

Arctic sea ice / Re: The Rammb Slider Thread
« on: June 01, 2019, 10:27:48 PM »

I remember seeing little cyclonic features like that in 2013...14?

There was some discussion but no conclusions.

I suspect they are fairly common, but exist in the lowest part of the atmosphere along frontal boundaries.  Since they are so low, higher clouds likely obscure them normally.

Speaking of swirls, some neat, fractal-like ones in the Greenland sea today.

Needs click, band I2, because it's the highest resolution.

Arctic sea ice / Re: The 2019 melting season
« on: June 01, 2019, 07:48:47 PM »
These large floes don't seem to have the strength like 2016 in the Beaufort.  I hope this isn't the thicker, multi year ice that's been discussed.

This was the largest chunk. (Requires a click)

14 hour loop, ending on June 1, 01 UTC

12 hour loop.

Arctic sea ice / Re: The Rammb Slider Thread
« on: May 30, 2019, 01:23:24 PM »
Here's the area in the Kara Sea where more darkening in band M8 is evident.  I hypothesize that the thin, low clouds produced drizzle (liquid), wetting the snow, where the thicker clouds were able to generate higher precipitation rates, and thus snow, leaving behind the white streaks.

Click to run

Arctic sea ice / Re: The Rammb Slider Thread
« on: May 30, 2019, 10:32:51 AM »
worldview terra modis corrective reflectance 367 picks up the same striations on may26-28. I'm thinking peak sunlight through different layers of cloud combined with warm air temperature for a shortish time period. (click to run)
Melt ponds between pressure ridges, my 2 cents worth.
That's kinda my thinking as well, although I think that the dark is wet snow, not quite liquid water. 

The pressure from the Beaufort ice getting shoved westward by the winds must've piled the ice up somewhere.  As the pressure ridges rose up, the extra weight then lowered the troughs between ridges, allowing see water to saturate the snow.

I noticed the same with the other dark spots too.

Could it caused by rain?

I'm coming around to the idea that the dark areas in band M8 are representing wet snow, and whiter areas are drier/colder snow.  I think in many of these cases, we are seeing the snowpack "ripen", meaning that it has softened to the piont it's melting so that it's surface is wet, but it's still very white, as the water can't pool on the surface yet.  That's why everything looks white in the visible bands, but picked up by the near infrared bands and displays as darker.

Today's interesting area of darkening is SE of Wrangel Island.  Here we see a storm passing through, but offering is a window through the dry slot.  A close look reveals some white bands that follow the cyclonic curvature of the storm. My interpretation is that the majority of precipitation that fell was a mixture of rain and snow, this wet down the snow (dark patches).  The whiter arcs are areas where the the precipitation came down hard enough that it was able to stay snow.  This is very common for storms where the temperatures are neat 0°C, the heavier stuff creates more cooling in the column and can drag down enough cold to keep it snow.

There's some similar patterns emerging in the Kara Sea this morning, but waiting for a few more images to load for that area.

Edit: added the Bremen cause color, as it picked up on the "torching" in the Chukchi where I feel the rain/snow mixture fell.

Requires a click

Getting closer

Arctic sea ice / Re: The Rammb Slider Thread
« on: May 28, 2019, 12:36:44 PM »

Arctic sea ice / Re: The Rammb Slider Thread
« on: May 27, 2019, 11:48:57 PM »
Okay, instead of clogging up the melting thread with my speculative post, this fits well here.  I was perusing the arctic using band M8 ("snow/cloud"), and was struck by some features on the Pacific side, these also show up in the two "snow/ice" bands. As an aside, the "I" bands are 375m resulting, "M" bands are 750m.  They are clearly features of the ice, not atmospheric, but I'm not willing to go as far as saying it is wetness, as much as I'm tempted.  The satellite definitely "sees" something, but I can't discern if it's a roughness thing, a temperature thing, or a wetness thing, or even a combination.  I've reattached the NPP satellites a bit, but haven't gained clarity.  Incidentally, the area that uniquorn referenced at 85.3N, 96.5E shows as a dark spot. (Third attachment, still image)

First attachment is north of the Chukchi. (Click it)
Link to are area

Second is further north. (Click it)

Arctic sea ice / Re: The 2019 melting season
« on: May 27, 2019, 04:36:52 PM »
Plotted the average skin surface temp from May 1-25 for the last 8 years. Sorry about the resolution, I was trying to save space.  2012 is upper left, 2019 lower right.

Arctic sea ice / Re: The 2019 melting season
« on: May 26, 2019, 02:27:23 PM »
Dove-tailing with the melt pond and snow cover discussion, here's a couple of screen grabs of the snow cover model from Climate Reanalyzer; the first is today, the second is for June 1st.

The takeaway is, GFS predicts snow cover over the next 6 days will be hammered, seriously.

A lot of that melt - 6-10CM worth - will be on the snowpack in the CAB.

I'm wary of the *raw* GFS data and its handling of snowmelt, especially on the ice.  The GFS is not coupled to sea ice, and also has issues dealing with boundary layer (the part that interacts with earth's surface) temperatures.

First attachment
The plots provided by the NOAA/ESRL Physical Sciences Division, Boulder, CO from their Web site at , which are forced by the GFS forecast, but with a markedly different result. Note that the upper right panel, "GFS ice area", remains unchanged through the 7 day forecast, as its un-coupled"

Second attachment (Requires a click) is the 10 day sea ice forecast from the ECMWF, available at , this is a coupled model.

Arctic sea ice / Re: The 2019 melting season
« on: May 26, 2019, 01:23:02 PM »
May 21-25.
On top of other comments, it seems like the Beaufort expanded and solidified, almost as if a refreeze was going on. I would say it's probably a removal of the effect of clouds on the sensor, or a freezing of surface meltwater on the ice, but would like to hear more expert opinions.
Not an expert here, but I'd say it's a result of the cyclone that moved through the region.  It finally reversed the persistent easterlies that dominated the Beaufort for a week or so, and pushed sea ice back to the southeast.  I'm sure that the storm brought precipitation, and some wet snow can't be totally ruled out, in my humble opinion.

Arctic sea ice / Re: The 2019 melting season
« on: May 24, 2019, 12:38:27 PM »
7 day Melt pond fraction forecast from ESRL, Physical science division.

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