Home brew AMSR2 extent & area calculation

[Wipneus]

The ice is finding the exit through Fram Strait easily. At the same time the ice area and extent in the Greenland Sea are rather low, is all that thick ice melting so quick?

The animation will start after a click. Contrast is exaggerated to make the movements visible.

[jdallen]

The ice is finding the exit through Fram Strait easily. At the same time the ice area and extent in the Greenland Sea are rather low, is all that thick ice melting so quick?

Nearby SST's are quite high - probably enough to tear off a couple CM/day.  It gets worse further south.  So I'd say that yes, a lot of that ice is melting as it makes its journey down the coast.

[Edit:] Do recall, further down the coast, those storms have been dropping a lot of precipitation as rain, rather than snow.  That would bring a lot of energy to the ice as well.

[seaicesailor]

The ice is finding the exit through Fram Strait easily. At the same time the ice area and extent in the Greenland Sea are rather low, is all that thick ice melting so quick?

Nearby SST's are quite high - probably enough to tear off a couple CM/day.  It gets worse further south.  So I'd say that yes, a lot of that ice is melting as it makes its journey down the coast.

[Edit:] Do recall, further down the coast, those storms have been dropping a lot of precipitation as rain, rather than snow.  That would bring a lot of energy to the ice as well.

Yes , one would expect ice getting closer to Svalbard too but seems to be melting out before reaching it.  That,  or the contrast of the images is fooling me. It could partly explain why extent did not respond to the conditions. Unsettling nonethelss.

[oren]

Does look like some melt off the Greenland coast.

[Neven]

The ice is finding the exit through Fram Strait easily. At the same time the ice area and extent in the Greenland Sea are rather low, is all that thick ice melting so quick?

Yes, this is the main reason I'm even contemplating a crazy low and early max this year, the fact that weather conducive to sea ice expansion hasn't delivered (so far).

[Wipneus]

Kara Sea region compared with 2015. Mobility is comparable to last year, but there seems to be less ice now (esp. the adjacent Barents Sea).  Again contrast is enhanced to see the ice movement, so the darker ice may not mean very much in numbers.

(click to start animation)

[oren]

My intuition insists when looking at this wonderful animation that the Kara sea ice is set for an early death this year compared to 2015. That black area at the south entrance seems ominous.

[Buddy]

My intuition insists when looking at this wonderful animation that the Kara sea ice is set for an early death this year compared to 2015. That black area at the south entrance seems ominous.

The Atlantic side of the  Arctic has been HAMMERED by warmer than normal air temps and SST's for the last 6 - 8 weeks.

Waiting for Svalbard to start serving Margarita's on the beach this summer....

In all seriousness.....it is NOT GOOD.  Now we have what will likely be a month of "plateauing" before the melt begins....and then another month after that when the melt REALLY picks up steam.

[Wipneus]

Meanwhile in the Beaufort/Chukchi regions, ice movements are impressive.
Contrast is increased to visualize the ice movements better.

[Wipneus]

Also in this 2-week animation of the sea ice concentration in the East Siberian Sea region, the ice is moving with good speed.

[Neven]

Wow. Thanks for the animations, Wip.

[Shared Humanity]

Also in this 2-week animation of the sea ice concentration in the East Siberian Sea region, the ice is moving with good speed.

Thank God for islands. Looks like they help to hold ice closer to the coast in a relatively stable location.

[jdallen]

Thanks, Wipneus!

Seem like the weather has turned the entire Arctic into one big gyre...

[JMP]

Having a hard time wrapping my head around this.

It seems so very early in the year for this much movement on this large a scale.
Is this event anomalous, unusual - if altogether typical, or is it completely unprecedented? 
Definitely due to thinning ice? or probably, or possibly, or unable to determine if, due to thinning ice?

[Wipneus]

Sharp declines in extent and area for the last two days. Most of it in the regions of St. Lawrence, Baffin/Newfoundland Bay and the Bering Sea region. This animation compares the ice concentration with last year, also a year with very low ice cover. The 2015 part shows how sudden extent can increase again (with very flimsy ice).

Must click to see anything animating.

[Pmt111500]

Having a hard time wrapping my head around this.

It seems so very early in the year for this much movement on this large a scale.
Is this event anomalous, unusual - if altogether typical, or is it completely unprecedented? 
Definitely due to thinning ice? or probably, or possibly, or unable to determine if, due to thinning ice?

Probably due anomalous warmth and generally thinner ice than in previous years. Wipneus' last animation would to me suggest there's some influx through Bering, but not that much. East Greenland current has been pretty active this winter, i gather, though I havent folllowed this very well. Are these two enough to produce such an extremely fast circulation on that scale? That looks like c 4 times the normal speed, if i'm not mistaken (happens every now and then).

[Wipneus]

Little ice in the Bay of St. Lawrence region as well as this animation shows.

Click to start.

[ghoti]

There is also very little ice in the great lakes. Can't wait for summer when the ice will begin to appear there

Oh actually, do the winter masks just assume full great lakes ice cover?

[Peter Ellis]

Current ice cover on the Great Lakes is ~23%, which is quite a bit lower than usual.

http://coastwatch.glerl.noaa.gov/glsea/cur/glsea_cur.png
http://coastwatch.glerl.noaa.gov/statistic/statistic.html
http://coastwatch.glerl.noaa.gov/statistic/ice/gif/s1973_2016_ice.gif
http://coastwatch.glerl.noaa.gov/statistic/ice/gif/m1973_2016_ice.gif
http://coastwatch.glerl.noaa.gov/statistic/ice/gif/h1973_2016_ice.gif
http://coastwatch.glerl.noaa.gov/statistic/ice/gif/e1973_2016_ice.gif
http://coastwatch.glerl.noaa.gov/statistic/ice/gif/o1973_2016_ice.gif

[Wipneus]

There is also very little ice in the great lakes. Can't wait for summer when the ice will begin to appear there

Oh actually, do the winter masks just assume full great lakes ice cover?

Unfortunately, the Uni Hamburg sea ice concentration product  masks out all lake ice. Unfortunately because I would expect the hi-res nature to be of much value there.

Sane extent and area calculations of sea ice leave lake ice out of course (throwing doubt about CT area).

See also my post about the Baltic last year that raised a question about the numbers. Here also the SSM/I and SSMIS sensors are far to "un-sharp" to accurate measurements: too high a shore/area ratio.

[LRC1962]

Going to wunderground maps and clicking on webcams, this year it seems no matter how detailed those satellites are... The only ice I can see are in sheltered spots. On top of that very low snow cover. This is February still not May. In Hamilton, went to bed last night with about an inch of snow on the ground. Big winds woke up and now nothing.
This means the ground is still very warm and wind plus a little heat has a horrifying effect.

[ktonine]

LRC1962 - similar story here in southern Wisconsin the past two days.  Temperatures rose into the 40s (F) and winds were constant with gusts up to 60 mph.  At midweek we had a few inches of snow on top of a thin bottom layer of ice across our yard.  Today the snow is almost completely gone and there a few small patches of ice left in spots and that should be gone by end of day.

The high winds also dried out the ground.  The dog has been out several times and I expect her to come back in with muddy paws, but she didn't. As fast as the snow/ice was melting it left little trace on the ground.  The sump pump has been quiet too.

[Wipneus]

In the first few frames of this animation of the Barents Sea region, the big arctic basin spinning wheel can still be seen. That has stopped for now, with winds favoring further drops in sea ice extent and area in the region.
The ice free region west and north of Svalbard seems to extent far to the east. That cannot be all caused by the West Spitsbergen Current?

[Pmt111500]

The ice free region west and north of Svalbard seems to extent far to the east. That cannot be all caused by the West Spitsbergen Current?

Nope. The NA drift or Norwegian current or what ever you call the drift bringing the warm water to Arctic has likely been extending to N.cape of Novaya Zemlya for a time now along it's west coast, and from the looks of that animation, Severnaya Zemlya could be the next turning point. The cold rather fresh currents from Arctic float on top of that and apparently now are the days when they aren't anymore strong enough to keep the ice coming through the channels there. Kara Sea might go permanently ice free shortly (next 20 years), like Barents has almost done.  Currently it would be something like the image below. The Severnaya branch would (in future) split also to the south, clearing Kara Sea coasts of ice.

[Shared Humanity]

From that animation, it sure looks like there is some melt going on.

[Tensor]

The winds, out of the south, Look to be pretty strong, in the last few frames.

[Wipneus]

Sea ice extent in the Kara region dropped about -31k today (with Barents a similar amount). Some interesting currents can be seen in this animation.

[Wipneus]

Total ice extent and area can make large swing in this transition to the melting season. The current positive swing (positive means numbers are going up) are mainly caused by ice in the regions of Okhotsk, St-Lawrence, Bering and Greenland Sea, all very peripheral.
Here is the Sea of Okhotsk region, rendered at 6.25 km to reduce image size, compared with 2015. Last year the ice cover was exceptionally low, now it is average.

Click to start the animation.

[Wipneus]

Extent +151k, area +178k. Blues everywhere in the delta-map.

[Wipneus]

Like last year, some dark shapes can be seen on the map between Svalbard and the Pole. They don't seem to reflect ice conditions, not seen in NSIDC and Jaxa's concentration maps. They are visible in Ads-nipr-jaxa's 89GHz images (https://ads.nipr.ac.jp/vishop/vishop-monitor.html).

[nukefix]

Like last year, some dark shapes can be seen on the map between Svalbard and the Pole.

Could they be attenuation due to snowfall or clouds in general?

[Wipneus]

Like last year, some dark shapes can be seen on the map between Svalbard and the Pole.

Could they be attenuation due to snowfall or clouds in general?

The ASI algorithm works out the ice concentration from the different brightness-es of H and V polarization in the 89 GHz band. Water on the surface has a high difference, ice  very low (nearly identical brightness).

The effect of clouds is always to increase the apparent concentration, I guess that is true for snow as well. Now the ASI algorithm has some mechanism (using lower frequency bands) to compensate these effects, so in theory if it over-compensates the increase would change into a decrease.

However, as can be seen in the raw 89GHZ polarization-ratio images in Jaxa's sea ice monitor, the effect is already seen in the raw brightness signals, here we have not such a case.

I should mention that in the posted animations the darkening is exaggerated to make the ice movements more visible.

 

[Frivolousz21]

Ice thickness

[Jim Hunt]

Ice thickness

How could the thickness of the ice change so swiftly? Or have I totally misunderstood your (overly brief!) remark?

[oren]

Ice thickness

How could the thickness of the ice change so swiftly? Or have I totally misunderstood your (overly brief!) remark?

Had it been any briefer than that we would have only got the signature! 

[Wipneus]

An animation of the ice concentration Baffin/NewFoundland Bay region. It is rendered in 6.25 km/pix resolution to be able to show the full height from the Kane Basin down to the ocean near Newfoundland. In the south the concentration seems to have impossible large variations, showing the difficulty that the ice algorithms (it is visible on Jaxa and NSIDC too) have in this corner. Maybe partly explained by the fewer satellite scans at this lower latitude.

[BornFromTheVoid]

I wonder if the issues in that area are related to the rather intense depressions that frequently cross over? While passive microwave generally deals with cloud cover quite well, I think that thick cloud with heavy precip can have some influence. Couple that with the storms delivering short-lived rainfall and transient warm sectors and you've got a lot of factors that can alter the readings.

[Yuha]

The weather has been quite variable around Newfoundland.
Here's the daily mean temps at St. John's airport in Newfoundland Feb 17-27:
+7.8, +3.6, -4.8, -7.0, -5.2, +1.0, -6.3, -8.4, +4.5 +8.3, -0.8
The warmest days have also seen a lot of rain.

The data is from here:
http://climate.weather.gc.ca/climateData/dailydata_e.html?StationID=50089

[Neven]

Yes, I had noticed that flashing too on the UB SIC maps.

[Shared Humanity]

Just my inexpert opinion but, looking at this animation, I think Nares Strait will be open for business early this year.

[LRC1962]

I wonder if the issues in that area are related to the rather intense depressions that frequently cross over? While passive microwave generally deals with cloud cover quite well, I think that thick cloud with heavy precip can have some influence. Couple that with the storms delivering short-lived rainfall and transient warm sectors and you've got a lot of factors that can alter the readings.

Browsing back in nullschool another factor coming to mind is the wind. Because of all those depressions, you have had a lot of wind. The thing is the wind direction is rarely the same day after day and can shift as much as 180^o .
To my mind that would help compact it some days, brake it up and spread it out others. Push it north or export it at other times. On top of that you would also be getting a lot of wave action during this time.

[Nick_Naylor]

"All truth passes through three stages: First, it is ridiculed; Second,  it is violently opposed; and Third, it is accepted as self-evident."
       - Chris Christie

[Wipneus]

On top of that you would also be getting a lot of wave action during this time.

Yes, waves will "fool the sensors" and cause false ice.

[Wipneus]

The ice in the Beaufort is trying to imitate the "crackzilla" from 2013.

(click to animate)

[Adam Ash]

Crackzilla: Interesting to see the westbound movement of ice from the Amunsden Gulf in 2016 not evident in the 2013 images. Is this warm water pushing through all the way from the Atlantic which is contributing to the extent of ice-free area against the coast?

[jdallen]

Crackzilla: Interesting to see the westbound movement of ice from the Amunsden Gulf in 2016 not evident in the 2013 images. Is this warm water pushing through all the way from the Atlantic which is contributing to the extent of ice-free area against the coast?

Doubt that; the activity there can be explained by tidal movement and weaker ice.

[seaicesailor]

Crackzilla: Interesting to see the westbound movement of ice from the Amunsden Gulf in 2016 not evident in the 2013 images. Is this warm water pushing through all the way from the Atlantic which is contributing to the extent of ice-free area against the coast?

Doubt that; the activity there can be explained by tidal movement and weaker ice.

I think so too. And the most interesting thing here imo is that the refrozen area will be adjacent to the continent rather than within the pack. Very extense area BTW, less espectacular but more important than the 2013 cracks id say

[johnm33]

Crackzilla: Interesting to see the westbound movement of ice from the Amunsden Gulf in 2016 not evident in the 2013 images. Is this warm water pushing through all the way from the Atlantic which is contributing to the extent of ice-free area against the coast?

Doubt that; the activity there can be explained by tidal movement and weaker ice.

The tides there are pretty small http://www.tide-forecast.com/locations/Sachs-Harbour-Nunavut-NWT/tides/latest, the movement is probably caused by persistent winds. There was certainly an appearance of movement of subsurface Atlantic waters, in that general direction, both in Wipneus animation above,[1836] and on Jim Hunts animation on the 2015/16 freezing season [600]. That stalling [and slapping together] looked like the cause of the thinning north of Svalbard. The exposed water is probably Pacific in origin but from when? Huge volume of ice on the move http://www7320.nrlssc.navy.mil/hycomARC/navo/beauforticespddrf_nowcast_anim30d.gif

[seaicesailor]

Crackzilla: Interesting to see the westbound movement of ice from the Amunsden Gulf in 2016 not evident in the 2013 images. Is this warm water pushing through all the way from the Atlantic which is contributing to the extent of ice-free area against the coast?

Doubt that; the activity there can be explained by tidal movement and weaker ice.

The tides there are pretty small http://www.tide-forecast.com/locations/Sachs-Harbour-Nunavut-NWT/tides/latest, the movement is probably caused by persistent winds. There was certainly an appearance of movement of subsurface Atlantic waters, in that general direction, both in Wipneus animation above,[1836] and on Jim Hunts animation on the 2015/16 freezing season [600]. That stalling [and slapping together] looked like the cause of the thinning north of Svalbard. The exposed water is probably Pacific in origin but from when? Huge volume of ice on the move http://www7320.nrlssc.navy.mil/hycomARC/navo/beauforticespddrf_nowcast_anim30d.gif

It is because of the winds, see drift maps
Classic Gyre and polar drift established these days

I meant weaker ice. Last years freezing in near Canada shores and Beaufort was late and drift has kept separating ice from continent recently

[johnm33]

seaicesailor
"I meant weaker ice. Last years freezing in near Canada shores and Beaufort was late and drift has kept separating ice from continent recently"
Absolutely, it's hard to think that the amount of movement evident in the animations would be possible if the ice was in any way consolidated. My own veiw is that it lacks mass too.