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Pagophilus

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Re: The 2018 melting season
« Reply #1150 on: June 11, 2018, 02:28:08 AM »
Nice back of the envelope calcs.  I believe you are absolutely correct, and this puts things in better perspective for me.  The papers I read had estimations that the Lena river waters are responsible for 5-10% of the melting of ice in the Laptev Sea. 

At peak heat flow in July, when the river is running at lower volume but higher temperatures, the figure you cite of 144 km2 per day for one meter thick ice could conceivably go up to around 500 km2 per day.  Of course, if the ice is half as thick that could be 1000km2 a day.  And 25 cm thick, 2000 km2 and so on.  But that would be the maximum, I think. 

There might be variations but your point remains: the Lena is a significant but relatively small factor in the melting of the Laptev. 


Quick back of the envelope:

Lena peak flow is 80,000 m3 per second, at 2°C, that has the energy to melt 2000 m3 of ice. So at the peak discharge it takes around 10 minutes to discharge enough water to melt 1 km 2 of ice 1 m thick. It can melt something like 144 km 2 a day. The latent heat of fusion of ice soaks up A LOT of energy.

It contributes a small fraction to the daily melt change.
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oren

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Re: The 2018 melting season
« Reply #1151 on: June 11, 2018, 02:30:23 AM »
I am not disputing your points in any way, nor do I doubt you personally in the slightest (in fact I avidly read your comments) but I believe the Slater projection maps are misleading and maybe close to intellectually dishonest.  As far as I can tell these projections are differently colored versions of the latest sea ice concentration maps (as per the NSIDC map in the image). Once different and prettier colors are applied to the data set, then a different scale is applied to the side.  Sea ice concentration that is perhaps now around 70% is ascribed a value of maybe 20%. And voila! The latest Slater Probabilistic Sea Ice Extent prediction for July 30!  Or some similar process.

If you don't believe me, please look at the images below.  The current ice extent on the Slater graph,once you look to its edges, is just a little inwardly displaced from today's ice distribution  And then look at the image on the right, for the actual distribution of ice last year on July 30.  There is almost zero probability that there will be significant ice in Hudson Bay, the south/west Kara Sea and Baffin Bay on this coming July 30.  But the Slater map has ice in all these places, because that is where 100% ice concentration exists right now. Other examples abound.  Hey, even I could do better than this! 

I know that I am but a lowly Lurker, but scientifically I think one of the worst things we have to deal with are grossly misleading methodologies or analyses.  These Slater maps seem to fall, perhaps inadvertently, into this category.  I leave it to others to decide, but is it worth Wipneus, Neven, oren and other notables discussing whether these projections should even appear on these forums?  BTW I believe these projections were once very good, but that Dr./Mr. Slater passed away -- I do not want to blemish his name in any way.
Agreed, the Slater maps currently seem to be wrong, and Hudson is the proof. But putting me in the same breath as Wipneus and Neven, well...  ::)  I am just an up-jumped lowly lurker.

The Pagophilus Probabilistic Model (which runs on KommonSenz 2.0) predicts with 90% probability that almost none of this will come to pass.
My favorite modelling platform!

I suppose the essence of ^ is a question: are we at a point where there has been enough heat accumulated in the High Arctic early enough in the season so that Coriolis Forcing will overcome an increasingly incoherent pack to shatter the high ice into disjointed land-adjacent agglomerations instead of a coherent whole centered on the CAB? Note, the thickest ice is now adjacent to Siberia or the CAA islands, Beaufort's MYI is effectively all gone.
I should not that this "split of a cohesive pack" is mostly meaningless. The pack only seems cohesive on satellite, but is made up of lots of floes going in various directions, as can be seen in many of A-Team's (and others') animations.


SMOS thin ice is also a mixture of transient storm artifacts (not really sub 0.5 m in the central Arctic) and possibly good data around the periphery (look for multi-day consistency). The physical basis of enhanced dielectric may be surface salt dissolving in rain/melt.

AMSR2 is still making good sense: dropping concentration in the expected places. The Laptev and Kara flaw polynyas have been, to this point, primarily wind driven. However their very size sets off feedbacks that enlarge them without wind.
This is a great animation. I believe a cliff is coming very soon to that Kara-Barents region, as widespread 20cm ice goes poof.
(where do you find SMOS thin ice maps in summer?)

bbr2314

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Re: The 2018 melting season
« Reply #1152 on: June 11, 2018, 02:48:46 AM »
I believe you are mostly correct however I also believe Slater's model does have some predictive capacity if you acknowledge its biases. We shall see!

Fair enough.  You know more than I do, you have found the model of use, and I truly respect that.  And we shall indeed see. 

But ... I'd just like to state that the Slater model for July 30 predicts at present that almost all of the CAB in terms of its current margins has an 80% chance of remaining intact, except there is a 50% chance that a colossal flattened gap will for some reason open up in the middle of the CAB.  The Slater model also predicts with 80% probability that all the ESS, the eastern third of the Laptev, all of the southern Kara, and half of Hudson Bay will be ice-bound on July 30. 

The Pagophilus Probabilistic Model (which runs on KommonSenz 2.0) predicts with 90% probability that almost none of this will come to pass.
I think using models/etc as indicators vs. verbatim makes more sense. So yes everything you say is true, but, perhaps there will still be substantial ice in HB/Kara come 7/30, e.g. the model is wrong on total extent at that date, but correct in that there could still be substantial positive anomalous area (just not THAT anomalous).  I think your PPM is probably superior ;)

A-Team

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Re: The 2018 melting season
« Reply #1153 on: June 11, 2018, 03:01:16 AM »
Quote
where do you find SMOS thin ice maps in summer?
The Bremen product differs in some respects from Hamburg (which ceases in late spring). There are issues with ground-based radio frequency interference, even though this is a reserved wavelength. The rfi choice suppresses some of that and is used above.

https://seaice.uni-bremen.de/data/smos/png/ data archive
https://seaice.uni-bremen.de/thin-ice-thickness/ explanation

[IMG]   20180609_hvnorth__l1c.png   2018-06-10 07:30   292K   
[IMG]   20180609_hvnorth_rfi_l1c.png   2018-06-10 07:30   292K   

Pagophilus

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Re: The 2018 melting season
« Reply #1154 on: June 11, 2018, 03:29:43 AM »
Thanks, oren and bbr.    I'm still laughing.   And still learning.
You may delay, but time will not.   Benjamin Franklin.

slow wing

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Re: The 2018 melting season
« Reply #1155 on: June 11, 2018, 04:53:53 AM »
 As I understand it, the Slater model isn't intended to produce an exact map where they stand by the prediction at each point on the map.

  Ice can move around, for instance, so a hole in the ice in one place now can move to a different place in 50 days time.

 I recall that in past years that map has shown, for example, a bar of remaining ice across the Hudson Bay that was obviously unphysical.

 In my opinion the Slater method is a powerful and helpful way to predict sea ice extent.

 It is a public service that they also provide the map for our benefit and we should be grateful for that rather than casting aspersions on it based on its detailed features.


... Hey, even I could do better than this! ...
::) This is really not that type of forum.
« Last Edit: June 11, 2018, 05:02:12 AM by slow wing »

aperson

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Re: The 2018 melting season
« Reply #1156 on: June 11, 2018, 05:00:07 AM »
It is a public service that they also provide the map for our benefit and we should be grateful for that rather than casting aspersions on it based on its detailed features.

Agreed, and I recommend the standard weather modeling approach to interpreting output from it: "All models are wrong, but some models are useful."
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Re: The 2018 melting season
« Reply #1157 on: June 11, 2018, 05:31:04 AM »
Comparing last years SSTA with this year, June 10.
And yay! What fun! You far northers don't have any idea what real weather is. I'm in the central plateau mountains. Got multiple tarps lashed with couple hundred metres of cord over my tent in a grove of trees. Looks like a spiders web. Gusts over 140kmph forecast to start in the next few hrs. Ain't life glorious.  8)
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Telihod

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Re: The 2018 melting season
« Reply #1158 on: June 11, 2018, 07:48:13 AM »
The Hudson Bay is getting roasted.


subgeometer

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Re: The 2018 melting season
« Reply #1159 on: June 11, 2018, 08:21:58 AM »
According to WindyTv's ECMWF temperature map air below 100m altitude is immediately losing 15-20C as it enters the Laptev Sea - I made the crude calculation that the ~110kg of air in a 1m2 area below 100m altitude  loses enough energy  to melt 6mm of ice over 1m2. Not a lot if the air stayed still maybe but with 19kt winds off the land the coastal ice will be getting hammered.

  And there is plenty of warmth further aloft , with temperatures peaking at 925hPa at 19C, way out near the CAB, and above freezing almost to 3000m across the Laptev and a swathe of the CAB. It would be interesting to know what proportion of the energy in the air will ultimately be transferred to the ice, - I don't know enough about atmospheric physics to even make a guess - but eg if all the warmth to 925hPa were transtered to the ice, that would melt several cm over the region, adding to insolation losses and bottom melt. And warm wind continues to blow in, with clear skies under a high

And more hot influxes will relentlessly follow, according to the forecast

With the widespread above freezing temps could the wide swathes of thin ice that appear in the last frames of ATeams SMOS be at least in part the effect of meltponding and wet ice?

I've attached the windyTV forecast map for 929hPa and at 100m altitude at around the start of current forecast

gerontocrat

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Re: The 2018 melting season
« Reply #1160 on: June 11, 2018, 11:00:34 AM »
Nice back of the envelope calcs.  I believe you are absolutely correct, and this puts things in better perspective for me.  The papers I read had estimations that the Lena river waters are responsible for 5-10% of the melting of ice in the Laptev Sea. 

At peak heat flow in July, when the river is running at lower volume but higher temperatures, the figure you cite of 144 km2 per day for one meter thick ice could conceivably go up to around 500 km2 per day.  Of course, if the ice is half as thick that could be 1000km2 a day.  And 25 cm thick, 2000 km2 and so on.  But that would be the maximum, I think. 

There might be variations but your point remains: the Lena is a significant but relatively small factor in the melting of the Laptev. 


Quick back of the envelope:

Lena peak flow is 80,000 m3 per second, at 2°C, that has the energy to melt 2000 m3 of ice. So at the peak discharge it takes around 10 minutes to discharge enough water to melt 1 km 2 of ice 1 m thick. It can melt something like 144 km 2 a day. The latent heat of fusion of ice soaks up A LOT of energy.

It contributes a small fraction to the daily melt change.

What about Albedo?

I presume that the flood water coming down these Siberian (and North American) rivers is not a beautiful clear and bright mixture of white ice and transparent water but full up muck - sediment, organic matter (and the occasional dead animal), and being less dense than sea water a brownish layer of river water will spread over a considerable area. Albedo must surely drop, with a considerable impact on heat capture as we are in maximum insolation?.

We are talking about a considerable number of cubic kms spread out in a thin surface layer.

Any studies on this?

EDIT: I believe the fresh water from the Amazon spreads over the ocean surface out to a distance of up to 150 miles from the river mouth - peak flows from the Lena exceed Amazon flow?
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slow wing

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Re: The 2018 melting season
« Reply #1161 on: June 11, 2018, 11:20:22 AM »
My understanding is that the water from the Lena River can contain so much sediment that it can be denser than the sea water when it enters the Arctic Basin and so sink underneath it rather than floating on the surface.

Sorry, I did a web search but can't find a reference to support this. Anyone?
« Last Edit: June 11, 2018, 11:26:22 AM by slow wing »

JayW

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Re: The 2018 melting season
« Reply #1162 on: June 11, 2018, 11:44:23 AM »
According to WindyTv's ECMWF temperature map air below 100m altitude is immediately losing 15-20C as it enters the Laptev Sea - I made the crude calculation that the ~110kg of air in a 1m2 area below 100m altitude  loses enough energy  to melt 6mm of ice over 1m2. Not a lot if the air stayed still maybe but with 19kt winds off the land the coastal ice will be getting hammered.

  And there is plenty of warmth further aloft , with temperatures peaking at 925hPa at 19C, way out near the CAB, and above freezing almost to 3000m across the Laptev and a swathe of the CAB. It would be interesting to know what proportion of the energy in the air will ultimately be transferred to the ice, - I don't know enough about atmospheric physics to even make a guess - but eg if all the warmth to 925hPa were transtered to the ice, that would melt several cm over the region, adding to insolation losses and bottom melt. And warm wind continues to blow in, with clear skies under a high



Most of the time, air near the surface is warmer than aloft, but often when there is snow and ice on the surface, an inversion develops.  Low clouds and fog can prevent this warm air from mixing down, forcing the warmer air to ride up over the cold air.  I can't find any model that shows the mixing depth.  It's not always easy to scour out that surface cold.

https://worldview.earthdata.nasa.gov/?p=arctic&l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features(hidden),Coastlines&t=2018-06-11-T00%3A00%3A00Z&z=3&v=-33594.171304008225,-362428.14196693257,2264558.0330386385,2342688.515228058
« Last Edit: June 11, 2018, 12:03:30 PM by JayW »
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Aluminium

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Re: The 2018 melting season
« Reply #1163 on: June 11, 2018, 12:12:55 PM »
My understanding is that the water from the Lena River can contain so much sediment that it can be denser than the sea water when it enters the Arctic Basin and so sink underneath it rather than floating on the surface.

Sorry, I did a web search but can't find a reference to support this. Anyone?

Source.
Yearly average turbidity in the Lena is 43 g/m3. Maximum is 400 g/m3 in the lower reaches of the river.

Just interesting fact. The spring rise of the water level is about 28 meters in Kyusyur.

uniquorn

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Re: The 2018 melting season
« Reply #1164 on: June 11, 2018, 01:05:16 PM »
From the satellite images, despite the warmer weather, it looks like some of the Lena delta water flows over the sea ice and then freezes about 5km out, possibly as the initial surge dies down. At the larger western outlet into the Gulf of Olenekskiy there is a strong enough flow to melt the ice front progressively.

Worldview jun8-11

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Re: The 2018 melting season
« Reply #1165 on: June 11, 2018, 01:12:30 PM »
Albedo over half the Arctic has plumetted with vigorous 24/7 sunny skies.


Weather models say this will slowly grow this week
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subgeometer

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Re: The 2018 melting season
« Reply #1166 on: June 11, 2018, 01:22:42 PM »
JayW

In areas where snow remains the 100m temp drops at the snow area border on the image I posted, there is no snow remaining in lowland areas like around the Lena delta, where the warmest air was coming in, which waswarm down to the surface, temps up to high 20s. The model infers that the snow and ice reduce temps to not much above freezing for at least 100m up - where the air at 950hPa is hardly cooler than that at 925. A lot must have to do with the level of turbulence

edit: Jay, my apologies for garbling your name - I should consider things a bit more before posting late at night
« Last Edit: June 12, 2018, 04:26:14 AM by subgeometer »

slow wing

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Re: The 2018 melting season
« Reply #1167 on: June 11, 2018, 01:43:54 PM »
Albedo over half the Arctic has plumetted with vigorous 24/7 sunny skies.

Weather models say this will slowly grow this week

Courtesy of NASA worldview, here is a gif giving a year-to-year visual comparison for Terra true color on 11 June, up to this year and going back to 2011.

Speaking roughly, it's seen that the 'dirtiest ice' on average - presumably corresponding to lowest albedo - on this day was in the record-breaking year, 2012. There is some cloud cover obscuring the comparison but very roughly the order from 'dirtiest' to 'cleanest' might look something like:

1. 2012
2. 2016

3=. 2013
3=. 2015
3=. 2018 <==

6=. 2017
6=. 2011
6=. 2014

So this year we're somewhere in the middle of the pack.

The weather from here on in will of course have a big effect on the extent at the end of the melt season.

subgeometer

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Re: The 2018 melting season
« Reply #1168 on: June 11, 2018, 02:05:11 PM »
Weather right now is not all that conducive to ice retention, but great for imaging, with clear skies over broad swathes.

Meltponding is clear on the fast ice of the Laptev shore but I think you can also see it on the ice on the other side of the bite. Here are a wide view where I've pumped up the saturation to 100% on Gimp's slightly inadequate Hue-Saturation-lightness tool to attempt to bring out the blue of meltponds, along with a closer view of the mush beyond the Laptev where I brought out contrast using levels

edit:

In the bottom image the larger floes in the centre have a bluer tone than all the smaller "mush", suggesting it's too broken to hold much water in meltponds

« Last Edit: June 12, 2018, 04:30:23 AM by subgeometer »

FishOutofWater

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Re: The 2018 melting season
« Reply #1169 on: June 11, 2018, 02:06:00 PM »
We know from the Worldview images that fog and low clouds are not forming over the Laptev and ESS under these strong warm offshore winds. Turbulent winds and continuous insolation are drying and warming the top of the boundary layer so that low clouds don't form. Folks who, like I, have lived near the California coast have watched the low clouds and fog "burn off" mid day in the early summer are well aware of the effect of insolation on low clouds.

In the high Arctic the top of the inversion layer is warmed 24/7 in June by insolation. That's why we aren't seeing more clouds over the Laptev and ESS. Reflective snow has been keeping the rate of heating down, but it's melting at a record pace in that region now. Once that snow is gone much of the advected and heat will go into melting the ice from above and below as the melt pond covered ice lets solar radiation penetrate into the water below.

Remember that large PIOMAS volume anomaly on the Siberian side of the Arctic? Kiss it goodbye.

As the animation above shows, this is an unprecedented melt down for this side of the Arctic in early to mid June.

Pagophilus

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Re: The 2018 melting season
« Reply #1170 on: June 11, 2018, 02:33:15 PM »
Had not thought about albedo!  Attached is an image from a quick search from Worldview, showing what seem to be sediment-rich waters issuing from the Lena delta, spreading at least 100km into the Laptev.  (Algal blooms are also a possibility and perhaps these would be promoted by the nutrients in the Lena sediment).  No doubt there are better images available.     However, visually, these seem to increase albedo -- the seawater looks darker.  This is not necessarily the case on all solar wavelengths of course.   

Another possible factor is that particles in the water would absorb energy more intensely at the surface, rather than allowing the sunlight to penetrate too far.  So that might result in even warmer waters right at the surface.  That might offset any possible albedo increase to some extent. 

slow wing raises the interesting possibility of these sediment laden waters sinking rather than floating.   Aluminium, through a source from gerontocrat, provides a possible solution with the information that "Yearly average turbidity in the Lena is 43 g/m3. Maximum is 400 g/m3 in the lower reaches of the river."  So, if we accept this information, and ballpark the Lena's non-turbid water as 1000kg/m3, then it is possible to make the following very crude calculation.  Taking the maximum turbidity of 0.4kg/m3, that would make a cubic meter of Lena water have a density of around 1000.4kg/m3.   Sea water usually has a density of 1020 to 1029 kg/m3.  So, on this limited basis, and assuming equal water temperatures, the sediment-laden Lena waters would float.  This was probably Aluminium's point, I'm just parsing it out.  (BTW, Turbid currents can certainly be impressively dense, but the Lena goes through a delta, and probably sheds some of its sediment there).

For me, your albedo point is a very interesting one, even if it is hard for me to tease out its effect from the current information I have.


What about Albedo?

I presume that the flood water coming down these Siberian (and North American) rivers is not a beautiful clear and bright mixture of white ice and transparent water but full up muck - sediment, organic matter (and the occasional dead animal), and being less dense than sea water a brownish layer of river water will spread over a considerable area. Albedo must surely drop, with a considerable impact on heat capture as we are in maximum insolation?.

We are talking about a considerable number of cubic kms spread out in a thin surface layer.

Any studies on this?

EDIT: I believe the fresh water from the Amazon spreads over the ocean surface out to a distance of up to 150 miles from the river mouth - peak flows from the Lena exceed Amazon flow?
« Last Edit: June 11, 2018, 03:09:26 PM by Pagophilus »
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gerontocrat

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Re: The 2018 melting season
« Reply #1171 on: June 11, 2018, 04:33:11 PM »
I am gratified that my post about the albedo of mucky water got a reaction. Amateurs like me are always nervous of sticking an oar into specialist scientists' water.

The Lena apparently chucks about 200 cubic kilometres of water into the Arctic in June, and the Yenesei something similar right in maximum insolation.

Meanwhile, GFS via cci-reanalyzer says that within 24 hours from now temperature North of 80 will exceed 273.15 degrees Kelvin- and likely to stay that way.


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Re: The 2018 melting season
« Reply #1172 on: June 11, 2018, 05:16:31 PM »
The Lena apparently chucks about 200 cubic kilometres of water into the Arctic in June, and the Yenesei something similar right in maximum insolation.
I haven't waded through every post in this thread, so I don't know exactly where that "200 cubic km" figure came from, but I think it's somewhat less than that.

Average Lena River discharge in June for the previous four years:

2014: 12696 m3/second = 33 km3 total in June
2015: 13332 m3/second = 35
2016: 10641 m3/second = 28
2017: 10097 m3/second = 26

The "station" (actually a site measured by satellite microwave radiometry) is a bit upstream from the delta, so the actual total discharge would be slightly higher, but it shouldn't be off by too much -- almost all the watershed area is above the station.   

Source:
http://floodobservatory.colorado.edu/SiteDisplays/297.htm
http://floodobservatory.colorado.edu/DischargeAccess.html

Warning ... the data page for this station (first link) is horribly formatted.  Ugh.

Ned W

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Re: The 2018 melting season
« Reply #1173 on: June 11, 2018, 05:20:10 PM »
Here's the annual discharge timeseries for the Lena, from the Flood Observatory:



The early-June spike is impressive.

A-Team

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Re: The 2018 melting season
« Reply #1174 on: June 11, 2018, 05:27:49 PM »
Here is today's update for UB SMOS thinness, Ascat roughness, Osi-Saf drift, Jaxa RGB, and WorldView blueness. The SMOS is labelled A1-3 for the earlier anomaly and B1-4 for the one still progressing east across the Siberian side. Ice will move erratically with considerable shear over the next few days (3 hour forecast intervals GFS nullschool from 11 June 18 0000).
« Last Edit: June 11, 2018, 06:19:19 PM by A-Team »

bbr2314

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Re: The 2018 melting season
« Reply #1175 on: June 11, 2018, 05:31:49 PM »
Here is today's update for UB SMOS thinness, Ascat roughness, Osi-Saf drift, Jaxa RGB, and WorldView blueness. The SMOS is labelled A1-3 for the earlier anomaly and B1-4 for the one still progressing east across the Siberian side.
B4 would support the notion that ESS will be bifurcated from the main pack within 30-50 days or so. The situation could change but the consistency with the other frames and year-to-date weather conditions (IMO) would support the notion that the ice now failing on the SMOS maps is actually quite thin and vulnerable and will likely melt out before the thicker ice to its N & S follows suit.

To my eyes it is looking like the cause of ^ is major Atlantification of everything lighting up in B2/3/4 and that "feeling" the Pacific intrusion which is also abnormally severe this June. As the two tongues of proper ocean water come closer to one another they will begin to handshake / exchange is likely to begin / could we see the Gulf Stream end up as a cross-polar current?

gerontocrat

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Re: The 2018 melting season
« Reply #1176 on: June 11, 2018, 05:32:27 PM »
The Lena apparently chucks about 200 cubic kilometres of water into the Arctic in June, and the Yenesei something similar right in maximum insolation.
I haven't waded through every post in this thread, so I don't know exactly where that "200 cubic km" figure came from, but I think it's somewhat less than that.

Average Lena River discharge in June for the previous four years:

2014: 12696 m3/second = 33 km3 total in June
2015: 13332 m3/second = 35
2016: 10641 m3/second = 28
2017: 10097 m3/second = 26

The "station" (actually a site measured by satellite microwave radiometry) is a bit upstream from the delta, so the actual total discharge would be slightly higher, but it shouldn't be off by too much -- almost all the watershed area is above the station.   

Source:
http://floodobservatory.colorado.edu/SiteDisplays/297.htm
http://floodobservatory.colorado.edu/DischargeAccess.html

Warning ... the data page for this station (first link) is horribly formatted.  Ugh.
Maximum flow of the Yenesei 112,000 m3 sec, minimum 3,120 m3 sec, average 19,600 me sec. All the rivers flowing into the Arctic show a similar flow and the max is always in June.. It is the melting of 6-7 months of snow.

Average is a measure that disinforms on rivers such as these.
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Ned W

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Re: The 2018 melting season
« Reply #1177 on: June 11, 2018, 06:46:06 PM »
The figures I posted were for June.  Sorry if that wasn't clear.

Take the average discharge for the month of June in m3/second, multiply by 60x60x24x30, and divide by 1000^3 ... and you get the total volume for the month of June, which in recent years is between 25-35 km^3.

bbr2314

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Re: The 2018 melting season
« Reply #1178 on: June 11, 2018, 06:48:11 PM »
The latest GFS shows sustained and extreme heat across all Siberian seas. By the end of the run the Laptev is probably free and clear of ice and surface temps are pushing into the 60s as Siberia is bombarded with constant 80-90F readings.

Wonder if the imminent accumulation of shallow heat will lend itself to a more severe repeat of the recent GAC in the D10-20 period? The worsening contrast with extant ice/remaining snowcover (which is especially bright over NE Siberia adjacent to ESS!) should prove increasingly tantalizing to strong LP as the gradient widens.




gerontocrat

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Re: The 2018 melting season
« Reply #1179 on: June 11, 2018, 06:48:53 PM »
Hullo Nedw,

We've got a data problem here - your data vs. Wikipedia


Maximum flow of the Yenesei 112,000 m3 sec, minimum 3,120 m3 sec, average 19,600 me sec. All the rivers flowing into the Arctic show a similar flow and the max is always in June.. It is the melting of 6-7 months of snow.

Average is a measure that disinforms on rivers such as these.

I was on my mobile enjoying the June sunshine. But here are a couple of graphs to illustrate the point.

Edit:-
And here is my original posting
https://forum.arctic-sea-ice.net/index.php/topic,2278.msg156668.html#msg156668

Quote
The Lena River is certainly a big beast, with a huge maximum discharge when the snow melts. June is the big month - but apparently snow-melting is also happening in May now. Presumably large amounts (200gt ?) of fresh water entering the Laptev in just one month must impact how ice loss happens in the Laptev.   See data below and images attached.

And yes, this stuff is a wonderful distraction from less interesting but necessary work

From Wikipedia:-
The Lena (Russian: Ле́на, IPA: [ˈlʲɛnə]; Russian Buryat: Зүлхэ; Evenki: Елюенэ; Sakha: Өлүөнэ) is the easternmost of the three great Siberian rivers that flow into the Arctic Ocean (the other two being the Ob' and the Yenisey). With a mean annual discharge of 588 cubic kilometers per year, it is the 5th largest river globally by discharge and the second largest of the Arctic rivers (after the Yenisey)[2]. It is the largest river whose catchment is entirely within the Russian territorial boundaries. Permafrost underlies most of the catchment, with 77% of the catchment containing continuous permafrost.

Mouth   Lena Delta 
- location   Arctic Ocean, Laptev Sea Basin   2,500,000 km2 (965,255 sq mi)

Discharge   for Laptev Sea[1]
 - average   16,871 m3/s (595,794 cu ft/s)
 - max   241,000 m3/s (8,510,835 cu ft/s)
 - min   366 m3/s (12,925 cu ft/s)
35% of the annual total (588 km3)discharged in June = approx 200 km3

What is going on?
« Last Edit: June 11, 2018, 07:02:54 PM by gerontocrat »
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Tor Bejnar

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Re: The 2018 melting season
« Reply #1180 on: June 11, 2018, 06:58:52 PM »
Re: Lena River discharge in June

With a mean annual discharge of 588 cubic kilometers per year (per Wikipedia), and 35% (plus) of the discharge happening in June (per the above graph provided by gerontocrat), I calculate 205 (plus) km3 discharge in June.  This supports what gerontocrat posted earlier today.

[Edit: or using Aluminium's data below, nearly 192 km3 in June.]
« Last Edit: June 11, 2018, 08:01:17 PM by Tor Bejnar »
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Re: The 2018 melting season
« Reply #1181 on: June 11, 2018, 07:45:29 PM »
Lena at Kusur. Average monthly discharge in June is 74000 m3/s. The highest monthly discharge was 104000 m3/s in June 1989.

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Re: The 2018 melting season
« Reply #1182 on: June 11, 2018, 07:46:54 PM »
Re: Lena River discharge in June

With a mean annual discharge of 588 cubic kilometers per year (per Wikipedia), and 35% (plus) of the discharge happening in June (per the above graph provided by gerontocrat), I calculate 205 (plus) km3 discharge in June.  This supports what gerontocrat posted earlier today.

And 205 km3, at 1C melts about 2500 km2 of ice 1m thick. In the whole of June, it contributes to the melt, but not significantly. The delta is about 400km wide, so basically it's enough heat to melt out the front of the delta to a distance of 6km. The water may be warmer, the ice thicker. It's just a ballpark, but it seems about right looking at worldview.

 

gerontocrat

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Re: The 2018 melting season
« Reply #1183 on: June 11, 2018, 07:59:24 PM »
Re: Lena River discharge in June

With a mean annual discharge of 588 cubic kilometers per year (per Wikipedia), and 35% (plus) of the discharge happening in June (per the above graph provided by gerontocrat), I calculate 205 (plus) km3 discharge in June.  This supports what gerontocrat posted earlier today.

And 205 km3, at 1C melts about 2500 km2 of ice 1m thick. In the whole of June, it contributes to the melt, but not significantly. The delta is about 400km wide, so basically it's enough heat to melt out the front of the delta to a distance of 6km. The water may be warmer, the ice thicker. It's just a ballpark, but it seems about right looking at worldview.

I posted this starting with : What about albedo? i.e. dirty water. And is there data on water temperature by the time it reaches the delta, especially later in the month?

https://forum.arctic-sea-ice.net/index.php/topic,2278.msg158240.html#msg158240
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Re: The 2018 melting season
« Reply #1184 on: June 11, 2018, 08:13:19 PM »
Re:  Lena River discharge in June

OK, so the Arctic GRO data (the source for the wikipedia figure) give an average of 183 km3 in June (1999-present) and the historical data that Aluminum cited shows 192 km3 (1934-2000). 

Those are both based on actual in-situ measurements, while the Colorado Flood Observatory data I cited are based on passive microwave remote sensing ... and the data page is (as I pointed out) a mess, which doesn't inspire a lot of confidence. 

So ... yes, you're probably right that the actual value is around 200 km3 (based on the actual in-situ data) rather than the 30 km3 reported by the CFO's inferred-from-microwave-emissions data.

Apologies for the distraction; carry on....

Tor Bejnar

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Re: The 2018 melting season
« Reply #1185 on: June 11, 2018, 08:36:36 PM »
Correlation of river water and local sea‐ice melting on the Laptev Sea shelf (Siberian Arctic)
(Bauch, et.al., 2013)
Quote
5.1 Potential Heat Input by River Water for Local Sea‐ice Melting ... The energy flux of the Lena River from May to July of ~9,100 × 1015 J could melt a water equivalent to 27 km3 or a 0.5 m thick layer of ice in the southeastern Laptev Sea (~59,000 km2 within 130–140°E and 71.5–73°N). This is an area where the sea‐ice cover generally vanishes early in the summer season (by late July) compared to the central Laptev Sea [Bareiss et al., 1999] (see also National Centers for Environmental Prediction reanalysis data [Kalnay et al., 1996]). This area is south of the recurring coastal polynya and covered by ~1.5–2 m thick fast ice in winter [Bareiss and Görgen, 2005; Dmitrenko et al., 2010a; Bauch et al., 2012]. Therefore, the initial heat supplied by the Lena River can account for about one quarter to a third of the energy needed for the melting of the ice cover in the southeastern Laptev Sea. This rough estimate suggests that river water may be an important heat source for the early breakup of sea‐ice cover in the proximity to the Lena Delta. Nevertheless, the initial heat contained in the river runoff alone is too small to melt even the area of the fast ice in the southeastern Laptev Sea that is usually free of ice rather early in the summer season. Overall, the calculated volumes of positive SIM fractions of 158 km3 and 109 km3 in 1994 and 2008, respectively, are much larger than the volume potentially melted by the initial heat contained in the Lena River water (maximal 45 km3/a). Therefore, solar radiation and sensible heat must be dominant sources of heat even though the initial heat of the river water might also be locally a significant source in the proximity to the Lena Delta during breakup.

This confirms several comments above - "small effect in the scheme of things"


I am aware that some river water flows on top of some fast ice, melting most/all of the snow and leaving some amount of silt in the process.  This silt will decrease the remaining ice's albedo (big time).  The area where this happens is very small compared with the Laptev Sea's area.

Given that water has low albedo, it might be that dirty water has higher albedo, but I couldn't find anything that discusses this. It will also have a higher density, so it could hold more heat, per volume, I presume.
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gerontocrat

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Re: The 2018 melting season
« Reply #1186 on: June 11, 2018, 08:47:09 PM »

This confirms several comments above - "small effect in the scheme of things"

Ho hum,

As one of our Supermarket chains (Tesco) says - "Every little helps". (and interesting)

I bet you it is quite a sight when these rivers are in flood, even if of minor significance in the scheme of things.
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Re: The 2018 melting season
« Reply #1187 on: June 11, 2018, 08:52:58 PM »
I believe the Slater projection maps are misleading and maybe close to intellectually dishonest.  As far as I can tell these projections are differently colored versions of the latest sea ice concentration maps (as per the NSIDC map in the image). Once different and prettier colors are applied to the data set, then a different scale is applied to the side.  Sea ice concentration that is perhaps now around 70% is ascribed a value of maybe 20%. And voila! The latest Slater Probabilistic Sea Ice Extent prediction for July 30!  Or some similar process.



There is obviously something wrong with that Slater map.

In the original Slater model, the probabilities depend not only on the current sea ice concentration, but also on the location of the grid point.  For a grid point in Hudson Bay the probability is calculated in a different way than for a grid point in the Central Arctic.  Here is an example from a few years ago (2016, when Slater was still alive) to illustrate this:


Tor Bejnar

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Re: The 2018 melting season
« Reply #1188 on: June 11, 2018, 09:01:45 PM »
A year or two ago I read IN THE KINGDOM OF ICE: The Grand and Terrible Polar Voyage of the USS Jeannette , and what is described chattered my bones.  In the dead of winter the shipwrecked explorers knew they had to get off the Lena delta because of the evidence left by previous spring floods.
 
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Re: The 2018 melting season
« Reply #1189 on: June 11, 2018, 09:30:56 PM »
Quote
rivers of minor significance
Nasa came to a different conclusion in the case of the smaller Mackenzie River in 2012 ... after an ice dam gave way, Aqua infrared showed phenomenal near-surface warming of an area ~ 500 km x 500 km. (In the case of either suspended sediment or algal bloom, heat from sunlight is captured higher up in the water column than it would have been otherwise.)

https://earthobservatory.nasa.gov/IOTD/view.php?id=83271

http://www.slate.com/blogs/bad_astronomy/2014/03/06/arctic_sea_ice_warm_rivers_help_accelerate_melting.html

https://www.wired.com/2014/03/grawk-warm-rivers-arctic-ice/

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2006GB002856 nutrients

Quote
Massive flood on the Mackenzie River 13 kya possibly triggered Younger Dryas cooling
https://blogs.agu.org/geospace/2014/12/17/new-evidence-massive-flood-mackenzie-river-13000-years-ago/

The Northern Hemisphere suddenly cooled about 12,800 years ago in an event named the Younger Dryas. Scientists have debated the cause for many years. One widely-believed explanation is that the massive but long gone Lake Agassiz in central Canada rapidly flooded fresh water east down the St. Lawrence River into the northern Atlantic Ocean. That pulse of fresh water interfered with warm ocean currents and triggered the cooling.

In 2010, geographer Julian Murton of the University of Sussex and colleagues found evidence of a gigantic flood along the Mackenzie River in Canada. They proposed that Lake Agassiz flooded north down the Mackenzie into the Arctic Ocean. This fresh water pulse spilled over into the Atlantic Ocean and triggered the Younger Dryas, they said.

Recently, scientists discovered a massive deposit of Arctic seafloor sediment consistent with a huge flood coming down the Mackenzie River about 13,000 years ago. In 2013, the researchers retrieved sediment cores and used a chirp sonar to measure sediment layers beneath the Arctic Ocean near the mouth of the Mackenzie River.

In one core just west of the river delta, the scientists found a layer with much larger particles than the other layers and sudden changes in five other sediment properties. That layer was just beneath a seven-meter-thick section of unusually uniform sediment. Carbon-14 dating of core samples also pointed to a dramatic increase in how quickly the sediment accumulated in that section – from less than 0.5 meters per thousand years before and after the flood, to as high as 12 meters per thousand years during the flood.

The researchers also found the thickest flood deposits west of the Mackenzie – consistent with a massive outpouring of sediment from the river carried westward by ocean currents.

Quote
Collapse of a marine-based ice stream during the early Younger Dryas chronozone, western Canadian Arctic
TRLakeman et al
Geology (2018) 46 (3): 211-214.
DOI: https://doi.org/10.1130/G39665.1

New geophysical surveys and sediment cores constrain past dynamics of the Amundsen Gulf ice stream of the northwest Laurentide Ice Sheet during the last glacial episode. An ice-rafted debris (IRD) unit and its stratigraphic relationship to former grounding lines record the withdrawal of the ∼60,000 km2 marine-based ice stream. Calibrated radiocarbon ages from the IRD unit and from ice-contact raised marine sediments indicate that the ice stream retreated ∼250 km over a few centuries or less during the early Younger Dryas, ca. 12.80 kya. Despite a likely cooler paleoclimate, ice-marginal recession occurred at rates of at least 1 km/yr, triggered by grounding line retreat from a bathymetric sill and by a concomitant increase in calving margin length. Sediment cores from the adjacent continental slope confirm that the IRD-rich unit was also deposited in the Beaufort Sea as a chronostratigraphic marker bed. Such new evidence for widespread ice rafting establishes Amundsen Gulf as a discrete source area for early Younger Dryas sediment in the Arctic Ocean, including Fram Strait (between Greenland and Svalbard). The timing and scale of iceberg discharges show that Amundsen Gulf was a major conduit for fresh water to the Arctic Ocean during the Pleistocene-Holocene transition.
« Last Edit: June 11, 2018, 10:01:49 PM by A-Team »

gerontocrat

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Re: The 2018 melting season
« Reply #1190 on: June 11, 2018, 10:22:28 PM »
Quote
rivers of minor significance
Nasa came to a different conclusion in the case of the smaller Mackenzie River in 2012 ... after an ice dam gave way, Aqua infrared showed phenomenal near-surface warming of an area ~ 500 km x 500 km. (In the case of either suspended sediment or algal bloom, heat from sunlight is captured higher up in the water column than it would have been otherwise.)

Thank you so much, A-Team.

Science rules, OK.

And the rest of you:-  do you mind if I take a minute to feel smug about raising this "red herring" in the first place?

And I can't resist a before and after moment (in the images attached look at the albedo of the ocean)

ps : And winter snowfall was very big last winter and spring.
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uniquorn

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Re: The 2018 melting season
« Reply #1191 on: June 11, 2018, 10:36:21 PM »
Not much silt or algae in the Laptev gap yet, but it's warming up anyway. There is some light cloud in places that will affect temperatures so they should be taken only as a guide.
Worldview brightness temperature (band15) Laptev gap, Jun8-11. (light blue ~-1C, light yellow~4C)

uniquorn

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Re: The 2018 melting season
« Reply #1192 on: June 11, 2018, 10:49:52 PM »
I went through the ascat data and made notes on the earliest days when weather artifacts appeared and when significant features in the Beaufort sea were lost. It is a subjective analysis so others may differ on the day numbers. I'm afraid I haven't yet attempted to cross reference all the events with nullschool back to 2014, though that might be informative.

2018: day 152 significant weather artifacts, features lost
2017: day 143 significant weather artifacts, no strong beaufort features
2016: day 132 weather artifacts, day 157 features lost
2015: day 135 significant weather artifacts, features lost
2014: day 123 significant weather artifacts, day 176 features lost
2013: day 138 weather artifacts, day 160 significant weather artifacts
2012: day 140 significant weather artifacts, features lost
2011: day 126 significant weather artifacts, features lost

So it looks like data has been good for longer than usual this year(with one blip). Thanks to all at NOAA who continue to provide us with such a useful resource.

and Yaay! amsr2-uhh is back up again:)


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Re: The 2018 melting season
« Reply #1193 on: June 11, 2018, 11:07:12 PM »
Good the McKenzie subject has been raised. Its started raining quite significantly in its catchment and also the CAA. Courtesy of a very broad and soggy atmospheric river being cogged up direct from the gulf of Mexico, that the GAC is now feeding on in addition to what its gobbling from the Eurasian side. This pattern of sucking heat and moisture in off both hemispheres continents and spewing cold out Bering, Fram, and Nares, is very ominous for ice survivability. It may be that the right roundhouse jab of moisture injected from off Europe was just a feint,  and the King hit left now arriving is actually the knockout punch.
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Re: The 2018 melting season
« Reply #1194 on: June 11, 2018, 11:14:55 PM »
 While our attention has been diverted towards the Russian side of the Arctic, warm air has crept in from the south over the CAA and CAB. Temperatures running +2C at Resolute Bay, +3 at Eureka (with rain falling in both places), +7 at Arctic Bay and +4C at Alert (with sunshine). Dewpoints are generally at or above freezing as well. Model soundings show the freezing level up to around 5000ft (1600m) and strong warm advection in the low levels (strong winds veering with height). These conditions will last a few days. We should expect to see a strong breakout of melting and ponding over the next few days on that side as well.

Soundings were from the GSD sounding page at https://rucsoundings.noaa.gov/
Use the GFS (to 5 days) when plotting soundings and use the WMO 6-hourly increments when choosing times (00,06,12,18Z).

RoxTheGeologist

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Re: The 2018 melting season
« Reply #1195 on: June 11, 2018, 11:50:40 PM »
Quote
Nasa came to a different conclusion in the case of the smaller Mackenzie River in 2012 ... after an ice dam gave way, Aqua infrared showed phenomenal near-surface warming of an area ~ 500 km x 500 km. (In the case of either suspended sediment or algal bloom, heat from sunlight is captured higher up in the water column than it would have been otherwise.)

Thank you so much, A-Team.

Science rules, OK.

A

Note that the McKenzie was warm water heated behind an ice dam, and it was 10C by the time the dam broke.

From the NASA editorial:

The intensity of the warm-water pulse was exacerbated by the ice barrier, a natural dam fastened to the shore. When the warm Mackenzie River broke through this barrier, it was “like a strong surge, unleashing warmer waters into the Arctic Ocean that were very effective at melting sea ice,” said Nghiem. “Without this ice barrier, the warm river waters would trickle out little by little, and there would be more time for the heat to dissipate to the atmosphere and to the cooler, deeper ocean.”


It will be interesting to sea if this happens at the Lena, but as for now, the ice is still in front of the delta, so any pulse of meltwater from the Lena has been too cold to melt that completely out.





 

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Re: The 2018 melting season
« Reply #1196 on: June 12, 2018, 12:32:07 AM »
There is currently 31C and sunny in Churchill. Whatever ice is left there is currently cooked and torched.

uniquorn

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Re: The 2018 melting season
« Reply #1197 on: June 12, 2018, 12:48:06 AM »
Rapid melt at the Gusinaya River delta in the East Siberian Sea.
An update now the weather is clearer. Jun3-11

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Re: The 2018 melting season
« Reply #1198 on: June 12, 2018, 02:18:03 AM »
Over 80% of remaining Hudson Bay ice is now showing blue.

Unaltered Worldview image 
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Tor Bejnar

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Re: The 2018 melting season
« Reply #1199 on: June 12, 2018, 02:34:14 AM »
... Nasa came to a different conclusion in the case of the smaller Mackenzie River in 2012 ... after an ice dam gave way, Aqua infrared showed phenomenal near-surface warming of an area ~ 500 km x 500 km. (In the case of either suspended sediment or algal bloom, heat from sunlight is captured higher up in the water column than it would have been otherwise.) ...
Never thought about the Mackenzie ice dams (which develop to some extent every year, I recall reading) being part of the 2012 'perfect storm'.
Arctic ice is healthy for children and other living things because "we cannot negotiate with the melting point of ice"