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Messages - Nightvid Cole

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401
CAB area as of last update (to 07/24 data) is now below all but 2 of the pre-2007 years' minima!!!

402
Arctic sea ice / Re: What the Buoys are telling
« on: July 23, 2013, 02:36:42 AM »
Why are we trying to guess the thickness?  We have data from the colocated buoy, and it's 192cm thick [1].  All the guesses are useful for is proving just how bad the unaided human eye is at guesstimating distances from a small picture with no reference markers in frame.
http://imb.crrel.usace.army.mil/2012H.htm

[1] OK, the buoy appears to show the surface melt has stopped, and is thus possibly reading from the top of a melt pond.  Going by the melt rate before it hit the plateau (22 cm in about 10 days), we could maybe knock off another 20cm or so, for an actual thickness of ~170cm.

The discussion was about 2012J, not 2012H.

403
Arctic sea ice / Re: What the Buoys are telling
« on: July 23, 2013, 02:35:25 AM »
Watching the webcam photos and the movies I get a strong impression that the visible melt ponds seem to fill and flow the most under very cloudy conditions. My expectation was we'd see more melt and thus more pond growth and filling under a bright sunny sky.

Am I getting the wrong impression? Is radiative loss to the clear sky balancing the solar gain? This certainly isn't my experience everywhere else when I've actually done those measurements but I've never worked on the ice anywhere and certainly not on the arctic ice.

None of the buoys give us irradiance data to attempt to match the surface melt data. Heat flux measurements are bottom of the ice flux as far as I can tell not top down. I think bottom melt is known to increase under cloud cover especially during low sun angle hours but I really expected surface melt to be largest under full sun conditions. Perhaps under cloud there is more heat from condensation on the surface.

Yes, sun melts quite a lot, but so does a high dew point.

Even under clouds you have diffuse solar radiation, which is significant since Arctic clouds are usually fairly thin...

404
Policy and solutions / Re: 2 C Target No Longer Workable or Possible
« on: July 20, 2013, 11:52:12 PM »
According to Wili's reference

"“When we consider all targets jointly, CO2 emissions have to be cut by twice as much than if we only want to meet the two-degree target”, explains Steinacher.

The objective of limiting ocean acidification proved particularly challenging and is achievable only through a massive reduction in the emissions of CO2." 

This means that e.g. Kevin Anderson's estimate of 10% global CO2 emissions reduction/annum for decades to achieve 2 C ceiling has to be doubled to 20%/annum.  Various studies have shown a strong relation between CO2 emissions and GDP (e.g., http://visual.ly/growth-global-gdp-and-energy-related-co2-emissions), with the ratio varying slightly among studies.  With a 70% linkage, this means that, globally, we would have to reduce GDP ~15%/annum if we wanted to achieve CO2 emissions reductions on the order of 20%/annum.  The advanced nations would probably have to agree to more than 20%, and the developing nations to less than 20%.  So, which USA Presidential candidate will go into the debates proposing a reduction of GDP by 15-20% for decades to come?  And, isn't that really one of the two central problems we have in effectively combatting climate change, the other being the reluctance of the average voter to give up the good life' enabled by the unlimited availability of cheap fossil fuels?

This only tells us that, perhaps, intentionally causing global economic collapse is not the wisest way to reduce emissions.

It does not say that it is impossible to reduce emissions without sacrificing GDP, only that it has not yet occurred. There is a big difference between the two!

We need a whole lot more public funding, worldwide, to go toward renewable energy R&D and implementation.

And gradually increasing costs of fossil fuels. (If gas were $30 a gallon, who in their right mind would choose to live 25 miles from work?) If done right, the carbon taxes can produce the revenue to support the renewables. The problem is not a lack of solutions which are technologically possible, nor a lack of solutions which are economically possible, but a lack of solutions which are politically possible. Yes, we need scientists and yes, we need economists, but right now the limiting factor is unambiguously politics.

405
Arctic sea ice / Re: What the Buoys are telling
« on: July 20, 2013, 02:49:06 PM »
IMB 2013B reports that 3 cm has melted away in the last 24 hours or so, and the temperature underneath is increasing:

What do the thermistor data from last years' buoys look like for the second half of July?  We know the surface melt is way behind last year, can you tell us anything about the bottom melt?

2012L is the only buoy located really close to that position in the Beaufort and thus it is the only valid comparison. As of 07/20/2013 we have

Current Buoy Data (07/20/2013):

Pos: 74.69 N, 145.80 W

Air Temp: 0.85 C
Air Pres: 1017.48 mb




--------------------------------------------------------------------------------

Current Ice Observations (07/20/2013)

Snow depth : 0 cm (melted 06/18/2013)
Ice thickness : 266 cm

Since Deployment (08/27/2012)

Snow depth at melt onset: 15 cm
Snow melt: 15 cm (Began 06/09/2013)
Ice surface melt: 48 cm (Began 06/18/2013)

Ice bottom melt : 26 cm (Began 06/14/2013)
Ice bottom growth : 12 cm (Began 02/01/2013)

....

How exactly is 48cm of surface melt 'way behind', I ask?

406
Arctic sea ice / Re: Clouds blocking passive microwave sensing?
« on: July 19, 2013, 05:00:01 PM »
Maybe a combination of data from more different wavelength bands will do the trick?

Clouds shouldn't be similar to slush in that case, because with clouds you are dealing with Rayleigh scattering (wavelengths ~ 4 - 10 mm, much larger than typical droplets ~ 10 μm) in addition to absorption. With slush there is mostly absorption and not too much scattering since the dielectric constant is similar between solid and liquid states.

407
I think that such lakes certainly have something to tell us, although exactly how similar their mechanical-thermodynamic coupling properties are to sea ice in the Arctic is not obvious.

Perhaps the models of sea ice should be run on lake ice as a sanity check, with, of course, the attendant absence of salinity, lack of a halocline, and lower wind and tidal effects fed in. If nothing else, this might help constrain any parameters not otherwise measurable in the realm of more fundamental physics.

Maybe it would be better to do it on semi-enclosed ocean areas such as Hudson Bay and Baffin Bay, or even a fully enclosed body of saltwater such as the Aral Sea which freezes and thaws every year. For obvious reasons these are better models for the Arctic Ocean than small freshwater lakes. How similar is ice-out on large enclosed or semi-enclosed saltwater bodies (such as those just mentioned) to ice-out on small freshwater lakes?

408
CT update is out. Looking at the the sea ice concentration maps, is it normal to have so many areas of 60% to 70% concentration spread across the CAB?

No, it is not normal. It is a result of a mechanically weak ice pack that cannot keep itself solid. The extremely large percentage of first year ice allows huge stresses to build up and cause it to crumble.

This is why I don't expect an increase in SIA over 2012.

409
I suspect many of us wish PIOMAS would use atmospheric forecasts for the next few days and give us daily updated thickness maps, but, alas, it doesn't.

Perhaps it is the greater sophistication of APL-UW 's model that makes it take more computation time and thus cannot realistically update that much. In which case, it is nothing but the great speed-accuracy trade-off, with HYCOM going for speed and PIOMAS going for accuracy.

Or maybe the issue is that in the era of US government spending cuts/sequestration, barely any science can be done any more because the funding is so hard to get and so unstable. I'm a physics grad student in the US, and believe me, it sucks...

410
(...)

The straw man(men) were "the people who say HYCOM is crap" seawolf, a guest troll was making a personal attack against Friv, but disguising it as a generality. I agree with Friv, it is inconsistent to on the one hand dismiss HYCOM thickness as being over stated, but then getting excited when   it shows thin ice in the CAB. However I would not call HYCOM thickness cr@p, I would call it troll food.

It is unfortunate that they let "guests" post. We were having a rather jolly time naming the Basin Blight(thanks for that Terry)


Well, there needs to be a way for new posters to be able to accumulate enough posts to build status (I assume you aren't referring to unregistered users getting on...)

Maybe we just need a good moderator force. Until then, don't feed the trolls...



Speeking of which. The blight is not limited to the Laptev side. Polynyas are opening up elsewhere.



r05c03

That hole in the ice pack NE of Point Barrow is the biggest of the cracks from Feb/Mar (I've been tracking it on MODIS and ASCAT almost the whole time...)

411
Arctic sea ice / Clouds blocking passive microwave sensing?
« on: July 06, 2013, 11:05:16 PM »
If you look closely at the DMI ice concentration animation, it looks like you can see clouds and weather systems going by and blocking the signal.

If you look closely at the MODIS visible images for the same date, the clouds seem to be in the same positions as the transient white streaks on the DMI concentration maps.

If so, how does this not defeat one of the supposed advantages of using microwave data as opposed to visible?

412
I was expecting a serious crash, but HYCOM is still showing cold SST ' s even in the area where the ice is really broken up, and for it to remain that way through at least the 13th.

Not knowing what to think, I put in 3.0 - 3.25 . Maybe HYCOM doesn't account for the higher transmissivity of the broken-up ice and the 'interstitial slush'?

413

What sort of shape should we expect at minimum?

I think we should consider that ekman pumping pushing a lot of fresh water towards Beaufort from the weak CAB area is a likely reason for very slow start in Beaufort. Even if Beaufort still has time to melt out, what about CAB that is protected by the Beaufort ice.

Hence, I am thinking shape is going to be something like:



I am thinking that maybe the ice that is left may be unusually thick so we don't get a volume record even if area/extent might get quite close to record low.

The Laptev gobble might be a bit bigger but it has a tough task to compensate for the extra area in the direction of Beaufort.

I would be extremely surprised to see ice surviving below 79N in the Alaska sector (i.e. the longitudes that Alaska spans, not counting the part that pokes down along what would otherwise be Canada's west coast.)

The ice is very thin in that region based on the IceBridge data.

414
Who is still thinking, that we will see another record this year and why?

Me, for the same reason as before (reply #560).

I am expecting 5 - 8+ cm/day bottom melt over large areas of the CAB by month's end.

415
As I recall the open waters in the fractures caused lots of cloud/mist formation that would hamper radiation into space. I'd expect the ocean heat that was released would have had some effect on the nearby ice rather than simply being radiated away. Any precipitation would be as blanketing snow that would act to protect the ice from the very cold air.  The possibility of wave action & grinding may fragment some of the ice. These factors combined could equate to a positive feedback.
Once the leads have iced over there is still a lot of heat being released through the thin ice, but no additional water vapor. At this stage the fractures represent negative feedback.


My guess is that winter fracturing is a net negative feedback, though probably not a large one.


Terry

I'm not so sure it is a net negative, since the new ice is more transmissive to sunlight and allows more heating of the upper ocean in the spring.

And once that ice breaks up (which will happen much sooner than the surrounding, thicker ice), there could be enough room for swells to form inside the area, and thus break up the surrounding ice, although to be fair the wind speeds would have to be very high for this to make much difference...

416
The 12z GFS holds a cold pool over the arctic basin into July.

Cloudy and cold with relatively light winds ain't bringing the big melt.

The ice seems so rotten now, even an unusually cold, cloudy summer might just make the records from last year be 'only' shattered, rather than pulverized...

There is no guarantee that ice averaging 1.5M thick will melt out where as ice 3-4 meters thick under similar conditions.


http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?mosaic=Arctic.2013176.terra.4km

See the big clearing extending from Laptev almost to Point Barrow? The ice along most of it looks like it's been broken up into small floes with translucent slush puppie in between. This translucent stuff is just as bad (in terms of transmitting solar radiation to the water below) as a significantly reduced ice concentration, and given Perovich et al. as I discussed before, I now expect area, extent, and volume this September to approach half of last year's values.

The earth is overheating and wants to ditch its cap...

417
The 12z GFS holds a cold pool over the arctic basin into July.

Cloudy and cold with relatively light winds ain't bringing the big melt.

The ice seems so rotten now, even an unusually cold, cloudy summer might just make the records from last year be 'only' shattered, rather than pulverized...

418
Southern Beaufort Sea / Banks Island June 24, 2012



Compared to 2012, there's a lot of energy NOT being absorbed in the Beaufort Sea this year.

It's hard to see how 2013 can match 2012 with very little open water in the Beaufort.

A sufficiently large area with reduced ice concentration can easily absorb far more excess energy than a much smaller area of open water. Also this energy more efficiently melts ice rather than going into heating up near-surface water or air (or evaporating water for that matter.)

419
Has anyone here read the paper (by Perovich et al.  )

Sunlight, water, and ice: Extreme Arctic sea ice melt during the
summer of 2007
 
?

I suspect that this diminished concentration on the Russian side of the Arctic (and into the central Arctic Ocean) spells serious trouble. Consider that in 2007 the low concentration didn't emerge until mid- or even  late July. This year it emerged in mid- June , giving an extra month for the ocean to soak up the sun. (Sheryl Crow, anyone?) Furthermore, this month is at the worst possible time, when the sun is at its strongest for the year.

Perovich et al. show a bottom melt exceeding 2 meters in their graph, and that was when the low concentration started only in the third week of July. Does this mean the upper ocean will warm enough this year over most of the Arctic to melt 4+ meters of ice?

Over most of the area in question we only have 1 - 2 meters to begin with.

A few weeks ago I voted in the poll for area and extent to be slightly above last year. Now I think they might crash down to half of that. Too late to change my vote, though  :(

420
Arctic sea ice / PIOMAS forecast: how reliable?
« on: June 22, 2013, 02:39:40 AM »
PIOMAS initialized on June 1 predicts a very strange spatial distribution of ice in September:

http://www.arcus.org/files/search/sea-ice-outlook/2013/06/pdf/pan-arctic/zhang_lindsay.pdf

with a piece of ice against the Siberian coast failing to melt at all. This hasn't happened since what, 1998?

I am highly skeptical...

421
Is it just me, or do we have holes in the ice pack @ 87N 100E    now ???
We saw this in 2010, but only in August and September, not June!

http://www.iup.uni-bremen.de:8084/amsr2/arctic_AMSR2_visual.png

422
Arctic sea ice / Re: North American Ice Service Seasonal Outlook
« on: June 11, 2013, 08:51:02 PM »
While researching this evening I ran across the NAIS June 3 Seasonal Ice Forecast. I thought it might be an interesting benchmark for future comparison. The report pdf can be found here:

http://www.natice.noaa.gov/pub/special/nais_forecasts/2013/graphics/outlook/nais_seasonal_outlook_2013.pdf

What interests me most is that it does not forecast major ice pack elimination in the Beaufort north of 120 miles from the coast nor in the CAB above 75 N.

Which has not been the case even once since before 2007.

I don't believe them in the slightest.

423
No doubt the margin of error expands as one looks to the last days of a forecast... However... Wetterzentrale is showing a tentacle of very warm moving right into the dead center of the CAB by June 18th, with a 10 degree C bubble right over the north pole. These are 850 mb temperatures, by the way, not the surface (which for all we know could be several degrees higher still.)



Actually the surface doesn't get very far above freezing since it is constrained by melting (phase change fixes temperature) until there is open water. This is an inversion: near 0 deg C at surface, 10 deg C at 850 mb. Although the adiabatic lapse rate is always > 0 , the actual lapse rate can go negative, there is no physical contradiction.

424


Its not to do with slower rotation speeds of polar cyclones, its to do with them being near the pole. Ekman transport is driven by the offset between the axis of the cyclone and the axis of the earth. If a cyclone is over the pole, its zero.

Why does it depend on the axis offset like that? The Coriolis effect is maximum, not zero, at the poles.

425
Take a look at the prediction for June 6.  A big hunk of the upper left quadrant turns blue - quite thin ice for the start of the season.



Has this happened before, and can we rule out simple mechanical divergence without enhanced melting (which is reversible if the ice gets pushed back together)?

426
The 12z long range Euro would delay the onset of rapid melt like we haven't seen since pre 2007.

I think the 'critical period' is really from about June 5th to 15th, as this is when the snowmelt mostly occurs over the Arctic basin proper and thus reduces the ice albedo and increases heating of water beneath the ice, which results in bottom melt later in the season.

427
It was Hans Verbeek who linked in a blog thread recently to  http://climate.rutgers.edu/snowcover/chart_daily.php?ui_year=2013&ui_day=122&ui_set=2]http://moe.met.fsu.edu/snow/[url]  and reminded me of the significance of the changing seasonal snow cover pattern much debated by forum members. There you can see the recent pattern of intensifying May to October snow cover deficits.

So how is development? The Russian side has now moved into a clear snow cover deficit [url]http://climate.rutgers.edu/snowcover/chart_daily.php?ui_year=2013&ui_day=122&ui_set=2]  and reminded me of the significance of the changing seasonal snow cover pattern much debated by forum members. There you can see the recent pattern of intensifying May to October snow cover deficits.

So how is development? The Russian side has now moved into a clear snow cover deficit [url]http://climate.rutgers.edu/snowcover/chart_daily.php?ui_year=2013&ui_day=122&ui_set=2]http://moe.met.fsu.edu/snow/[url]  and reminded me of the significance of the changing seasonal snow cover pattern much debated by forum members. There you can see the recent pattern of intensifying May to October snow cover deficits.

So how is development? The Russian side has now moved into a clear snow cover deficit [url]http://climate.rutgers.edu/snowcover/chart_daily.php?ui_year=2013&ui_day=122&ui_set=2

In North America, the snow melt is shifting northwards rapidly, while still maintaining a significant excess anomaly of snow cover.

I agree with Crandles (significant rapid loss - "maybe ...") that this year's seasonal message from snow melt is not yet clear. But it has tipped a little towards becoming a signal favouring enhanced sea ice melting to come.

Watching with interest ...

http://climate.rutgers.edu/snowcover/chart_anom.php?ui_set=1&ui_region=nhland&ui_month=4

First positive April anomaly since 2003 and largest positive April anomaly since 1996.

That said, the anomaly now appears to be negative, by pixel-counting  http://climate.rutgers.edu/snowcover/chart_daily.php?ui_year=2013&ui_day=126&ui_set=2   (area graph on ASIB graphs page has 2 - 3 day lag so isn't yet showing the anomaly dropping below zero.) and given the 'normal' temps in North America now and eastern Siberia's forecast 'heat wave' over the next 10 days, looking at anomaly falling off a cliff very soon, further confirming the pattern of recent years as a climate shift and not just random variation (weather).

428
Arctic sea ice / Re: Year-round ice-free Arctic
« on: April 19, 2013, 12:27:45 AM »
Presumably, in a year-round ice free Arctic, the SST 's in the Arctic Ocean could begin to warm up very early in the spring (March or April??) and reach very high levels by late summer, especially over the shallow continental shelf portions. Since there are presumably a lot of clathrates on the sea floor there, storms during the summer which produce mixing will cause the warmth to reach the bottom and destabilize the clathrates, causing runaway hothouse Earth...

429
Arctic sea ice / Re: When will we see open ocean at the north pole?
« on: April 03, 2013, 06:43:24 PM »
Compare PIOMAS December Average thickness plot:
http://farm9.staticflickr.com/8229/8409256532_6b630dffa7_o.jpg

With Mercator Mid December thickness plot:
http://bulletin.mercator-ocean.fr/images/produits/psy4v1/psy4v1_20111221_22634/ocean/regions/arc/psy4v1_20111221_22634_arc_icethick_n0_t0.gif

There's a lot of ice in Mercator that's almost twice as thick as PIOMAS.

I don't use Mercator at all.

I'm assuming that you didn't realize that you are
comparing Dec 2012 PIOMAS to Dec 2011 Mercator?

430
Around 2.6 is my guess, so I've picked the upper bound from that to be conservative.  It would be utterly unprecedented to have two records in a row, so some bounce back from last year's low seems inevitable to me. [....]
Unprecedented? What about 2011 and 2012? We're talking about one-day CT area here.

Of course, you can just argue that it's unprecedented to have three records in a row, and thus we expect a bounce back, but this would borderline on moving the goal-posts :P

431
Arctic sea ice / Re: When will we see open ocean at the north pole?
« on: April 02, 2013, 07:04:46 PM »
Terry,

What do you think of the Mercator Ocean model?



http://bulletin.mercator-ocean.fr/html/produits/psy4v1/psy4v1_courant_fr.jsp

V

BTW

175 E lat. is usually called 175 E Long.

Ice over 3.25 meters thick near the New Siberian Islands? This is madness. All other sources seem to agree that ice in that region is first-year ice, which reaches a maximum thickness of 2 meters.

I think the modellers must have done a poor job with their sanity checks.

432
Arctic sea ice / Re: What will the Arctic resemble in 2050?
« on: March 24, 2013, 09:49:12 PM »
The albedo discussion here has been completely ignoring the all-important contribution from snow.

The ice effect is never really that huge because the magnitude of the area anomalies peaks in September or October, when the Arctic isn't getting much insolation any more. Additionally, the open water areas in the Arctic Ocean tend to be very cloudy, further reducing the albedo effect from melting sea ice.

Snow, on the other hand, has its biggest deficit in May and especially June. And anomalously early melting of snow on N America / Eurasia doesn't appear to lead to high local cloud cover. (If anything, it has the opposite effect!) Thus the albedo effect of snow, unlike ice, is given an enormous boost by its proximity in time to the Summer Solstice, and the feedback is not reduced by cloud effects.

Right now, the snow over the Arctic sea ice isn't gone until the end of June, particularly near the Pole and on the CAA side of the Arctic. So the ice is to some degree 'protected' from the highest insolation of the Summer Solstice around June 21st.

When the snow atop the Arctic sea ice is ALL gone before the middle of June and the ice heavily ponded (a few years from now ??? ), the ocean under the ice will warm up much more than it has been even in recent years, for three reasons. One, more insolation at the Solstice than later in the season. Two, higher solar radiation incidence angles near the Solstice mean a larger percentage of that insolation gets through the ice to be absorbed by the water underneath. And three, a longer snow-free period means more thinning of the ice, in turn making the ice not only more penetrable by the light, but penetrable by a larger increase than before, due to the exponential nature of the Beer-Lambert Law. Result: Near-complete melt-out by September due to catastrophic amounts of 'bottom-melt'.

The timing of snow cover retreat has advanced 3-4 weeks at very high Northern latitudes over the past few decades, and this trend is accelerating. Once it advances by an additional two weeks or so, the ice is toast.

433
Arctic sea ice / Gargantuan crack to come next week?
« on: March 19, 2013, 03:37:22 AM »
According to http://www7320.nrlssc.navy.mil/hycomARC/navo/arcticicespddrf/nowcast/icespddrf2013031718_2013032500_035_arcticicespddrf.001.gif   , there will be a line of extreme ice divergence through the central Arctic (passing approximately though the North Pole), parallel to the CAA coast, presumably this will create a crack as the ice has insufficient tensile strength to withstand it.

Could this be the greatest crack of them all?

434
Arctic sea ice / Re: What will the Arctic resemble in 2050?
« on: March 05, 2013, 12:36:24 AM »
I expect it to be roughly like Hudson Bay is now - mostly ice free for 6 months a year.

435
Arctic sea ice / Re: Arctic sea ice free (extent)
« on: March 04, 2013, 10:39:02 PM »
I picked 2017-2020, but I wouldn't be surprised if we have one last minimum slightly above 1 M km^2 again sometime in the early 2020s (and the deniers will proclaim it the beginning of a recovery). And the very next year it'll probably crash down to something like 500,000 km^2.

436
Arctic sea ice / Re: Operation IceBridge Featured in EOS - Jan 14, 2013
« on: February 20, 2013, 07:35:30 PM »
Should choose 03/27/2012 in drop down menu after clicking on that link - around when the data were presumably taken.

437
Arctic sea ice / Re: Operation IceBridge Featured in EOS - Jan 14, 2013
« on: February 20, 2013, 07:33:42 PM »
Why was it so thin even in the eastern Beaufort Sea, when that area had multi-year ice according to http://www.aari.ru/odata/_d0015.php?lang=1&mod=0&yy=2012   ?? Did that ice get attacked by warm water from below or simply diverge and thin?

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