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Tigertown

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Re: The 2017 melting season
« Reply #4050 on: September 07, 2017, 12:31:06 AM »
... Warmer winters are going to end up what kills the Arctic, not summer heat, I think.
Both. Summer heat does not have to be direct insolation (though chances are, that would also contribute much), - summer heat can and certainly will be increasingly large amounts of heat transported into the Arctic, both air and water currents. I simply fail to see how that (further) increase can not happen, long-term. It's already going on, and is one major reason we have such mild winters, no?
Exactly. The belated heat can arrive in the Arctic from any latitude. There is plenty to spare  where I am.

Pavel

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Re: The 2017 melting season
« Reply #4051 on: September 07, 2017, 11:39:20 PM »
The MYI chunks squeeze out of the Garlic Press

wallen

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Re: The 2017 melting season
« Reply #4052 on: September 08, 2017, 05:08:41 AM »
Excellent clear view of the east quadrant of CAB. Very lucky the melt season has been relative cool and slow on that sideas the sea ice is a total mess.

A-Team

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Re: The 2017 melting season
« Reply #4053 on: September 08, 2017, 06:41:29 PM »
Here is a sequence from the 3.125 km resolution UH AMSR2 sea ice concentration for the last 26 days. The 100% level is grayed out as nothing within is resolvable. However the crazy little floe whose voyage in the current, wind and tides is marked with a red star, shows specific ice features can be followed under favorable circumstances.

Hycom shows what the next week might bring: more garlic press plus odd goings-on near the Fram (arrows). Very little of the very thickest ice will be left by fall the way things are going.

ESRL shows ice thickness for the Beaufort thumb for the next 120 hours in 6 hour increments. It's underlying grid has resolution of 384 x 432, which is significantly higher than Piomas' 360 x 120 and  Hycom's (box of 100 grid points, 4th animation, from 365 day ave of motion vectors). If the ice here moves further in direction of the Alaskan coast (south is down in 3rd animation), it will find itself floating in much warmer waters.
« Last Edit: September 08, 2017, 08:02:55 PM by A-Team »

2phil4u

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Re: The 2017 melting season
« Reply #4054 on: September 09, 2017, 02:21:44 PM »
I dont know  weather but the form of the ice is very compact.
Cant see any big decline this year, maybe the record low is even 1.  September.
Also i wondered about the forecasts few weeks ago, the forecast was below 2016 and why the hell should it be below 2016 with much better Area, +400k Extent this time and a really bad time phase 2016.
I think if it keeps good we can say in 3-5 days, that refreeze is stronger now then melting.

A-Team

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Re: The 2017 melting season
« Reply #4055 on: September 09, 2017, 03:13:40 PM »
in 3-5 days, that refreeze is stronger now then melting
The best quantitative information we have on that -- the ESRL forecasts out to Sept 13th -- says no.

In the 20 frames below, 6882 pixels of bottom freezing areas are shown, almost entirely in the lower bins, but 96104 pixels of bottom melt, a ratio of 1:14. The second animation just lumps freeze (to red) and melt (to blue) categories for easier visualization.

The ESRL data is readily available online, refreshed daily, both as an attractive web page and as easy-to-plot grid data archive. To date, only 3 of our 1310 members have looked at it.

Despite its sophistication, the model may not give spot-on perfect results (eg no attempt is made to resolve ±0). However it's hopefully more accurate than feelings, hunches, intuitions, wishful thinking, Old Arctic trendings, clay tablets or guesswork. If someone has a better source of near-real time physical data, please include the link to it so others may evaluate it.

https://www.esrl.noaa.gov/psd/forecasts/seaice/
ftp://ftp1.esrl.noaa.gov/RASM-ESRL/ModelOutput/REB_plots.2017-09-08.tar.gz see Arctic10.gif
https://www.giss.nasa.gov/tools/panoply/ Panoply: double-click on any Geo2D for an instant map
« Last Edit: September 09, 2017, 03:49:24 PM by A-Team »

Tigertown

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Re: The 2017 melting season
« Reply #4056 on: September 09, 2017, 03:32:03 PM »
To date, only 3 of our 1310 members have looked at it.
You can make that 4 now.

Richard Rathbone

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Re: The 2017 melting season
« Reply #4057 on: September 09, 2017, 06:48:47 PM »

The best quantitative information we have on that -- the ESRL forecasts out to Sept 13th -- says no.


A model that struggles against an anomaly persistence forecast (which is what ESRL did during the refreeze last year according to their verification study) doesn't have a good claim to being the best available. It has promise, but its yet to deliver.

jplotinus

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Re: The 2017 melting season
« Reply #4058 on: September 09, 2017, 07:34:02 PM »
To date, only 3 of our 1310 members have looked at it.
You can make that 4 now.

5

But I'm not yet up to speed on use and interpretation of data. The learning curve may require some time.

Adam Ash

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Re: The 2017 melting season
« Reply #4059 on: September 10, 2017, 03:12:20 PM »
Thanks A-Team.  A great resource.
https://www.esrl.noaa.gov/psd/forecasts/seaice/

2phil4u

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Re: The 2017 melting season
« Reply #4060 on: September 10, 2017, 03:20:19 PM »
I was thinking about starting in 3-5 days not until then.
One reason for not this many observers could be that i cant really see if ice gets more ore less.
Maybe you could place a number, i cant count pixels ;)

Deeenngee

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Re: The 2017 melting season
« Reply #4061 on: September 10, 2017, 11:07:10 PM »
Another update of my descent to the min chart, as we still seem to be descending....
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A-Team

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Re: The 2017 melting season
« Reply #4062 on: September 11, 2017, 11:15:48 PM »
ESRL is terrible. I know of much, much better models (forget names). They’re described in peer-reviewed journals (don’t recall cites, paywalled so haven’t read) but that data (proprietary format, floppy disk by request) shows how bad the ESRL fall 2016 validation really is (can’t really give specifics, no time).
Thanks for sharing.

Actually ESRL did not even begin their archive until nine months later, on July 27th of 2017. ESRL did not go ‘whole Arctic’ until the 22nd of August 2017. The web site was first opened on August 23rd. ESRL products, as labelled in 20 pt font on all 37 daily graphics, are experimental. And that product mix is still being revised daily into September.

Only as the upcoming refreezing season progresses will sufficient product accumulate for evaluation, after which the much-published PI will publish another journal publication. For now, let’s not confuse validation with placeholder (lorem ipsum dolor...)

In my view, there is only do, or not do.

In physics, if no experimentally testable prediction is coming out the door, you’re not doing. For climate science, forecasting means an .nc data file and its graphic stably posted without delay or registration barriers to the open internet. It does not mean twitter media or a dead link to little endian Word compilation in a non-peer reviewed supplement of an outdated paywalled journal article. At this time, only ESRL and Hycom are predicting the Arctic Ocean ice; only ESRL provides the data files.

ESRL is about forecasting out to D5 (and for some observables, out to D10); Hycom goes to D7. At this time, both offer archives but neither posts hindcasts or reanalysis. To make a good forecast, ESRL needs a decent D0, the initial state. So there are two separate validation issues: how good is the D0 and, given a spot-on D0, how well does their coupled air-ice-ocean model move it forward to D5? However the nature of the Arctic ice is such that neither is easily tested:

We’ve agreed to agree (with some holdouts) that nobody has the slightest idea what the ice thickness really is, within 50% error, across the Arctic Ocean on a given day. We’re not on solid ground when 2m of observed “buttery ice” at the North Pole on 05 Aug 17 is held equivalent to 2m brittle ice in the Lincoln Sea (show me the Arctic-wide buttery ice map). There is a week of accurate but limited 2017 swath data off Alert but so far it’s unpublished.

In 2019, the Polarstern will spend a winter collecting real ice thicknesses by helicopters 35 km to the sides of its drift. That data may be an uncomfortable fit to certain model products followed on the forums (the ones that make testable predictions, not all do).

https://www.theatlantic.com/magazine/archive/2017/10/a-year-on-ice/537912/

Bottom melt? Nobody is down there in scuba gear; can predictions be assessed from a few broken-down buoys and moorings in wrong places? Rain gauges? Not a single one for an area the size of Europe. We go by droplets and soggy snow on a couple of web cams. That's a budget issue though, not string theory.

So while ESRL has gone all-in on ice thickness prediction, the best part really is their release of all the contributing components to that calculation (e.g. ice-to-ocean thermal flux daily graphic and its underlying .nc data). There’s no obligation to use all their inputs or computational pipeline. Anyone can stub in an improved ingredient if they have it, or use it for validation.

As examples, the UH AMSR2 3.125 km sea ice concentration is a far better product than some of the 25 km resolution competition. It’s backed by a careful journal article; the underlying .nc data accompanies the daily image; there’s no mickey-mouse registration barrier or ftp passwords. ESRL uses AMSR2 but not this one. So for a value-added hybrid concentration, the UH can be used as initial state until it runs out (day before) and ESRL can pick it up and take it forward to D5.

The time series shown below takes 20 archived ESRL initial states for ice thickness (which go up to today, Sept 10th) and pushes that out to the expected change in ice thickness on Sept 15th, D5. The archive is a bit awkward to use for this but a volunteer here is restructuring it in the auto-cloud.

The D5 image below has pixel counts next each palette tile. Taking the dot product of count and thickness bin to estimate volume change, it emerges that Sept 15 is a wash, relative to the 10th. There's slightly more melt than freeze but the difference is minor compared to error issues. This has been a very flat minimum and ESRL sees that continuing to mid-month.
« Last Edit: September 12, 2017, 04:04:00 AM by A-Team »

F.Tnioli

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Re: The 2017 melting season
« Reply #4063 on: September 12, 2017, 02:27:57 PM »
...
At this time, only ESRL and Hycom are predicting the Arctic Ocean ice; only ESRL provides the data files. ...
And one may well wonder why. Is the matter of this kind of prediction is of so low importance? I doubt that very much. Or is the world is lacking properly qualified scientists and/or computational power (for models) for having more than just one such prediction made? I doubt this very much also. Me, i suspect that many predictions of the sort are being regularly made, and exist even now. However, only ESRL's gets _published_, you see. Why? That's NOAA's child, ESRL, yes?

nick

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Re: The 2017 melting season
« Reply #4064 on: September 12, 2017, 09:09:30 PM »
...
At this time, only ESRL and Hycom are predicting the Arctic Ocean ice; only ESRL provides the data files. ...
And one may well wonder why. Is the matter of this kind of prediction is of so low importance? I doubt that very much. Or is the world is lacking properly qualified scientists and/or computational power (for models) for having more than just one such prediction made? I doubt this very much also. Me, i suspect that many predictions of the sort are being regularly made, and exist even now. However, only ESRL's gets _published_, you see. Why? That's NOAA's child, ESRL, yes?

The reality is that sea ice is of little importance either in weather modelling, population protection or commercial shipping. It's only of interest for it's own sake and that's not often a good attractor of funds.

Even in wave modelling (my ex-field) the bathymetry of the arctic means that what happens there has little affect elsewhere so ice is only an afterthought in most wave models (and doesn't really have much impact anyway).

The accuracy of weather models has dropped well off by the time they get to 7 days out but the ice doesn't actually usually change that much in that period so any change is well within the margin of error of the model, so it's just not that important.

Computer power is getting cheaper though and the media is paying more attention to the arctic so it's likely to attract more interest in the future. CPU cycles aren't a limiting factor btw, it takes NOAA only about 5 minutes to run a global wave model at 15 minute resolution out for 2 weeks and an ice model of just the arctic basin is probably a lot less intensive. The good news is that all US public bodies must make their output public domain so if they're doing it somewhere the output will be available on the noaa site (though not necessarily in a useful format nor easy to find).

magnamentis

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Re: The 2017 melting season
« Reply #4065 on: September 13, 2017, 12:01:34 AM »
i can't comment on your assumptions about the ice having little impact/importance to the rest of the global climate, just taking it as a statement and express my doubts, while even should that be as you say, the sea-ice is significantly impacted by what's going on on the planet as a whole (climate change etc.) and hence even should your assumptions be true and my doubts in vain, the ice is definitely one key indicator of ongoing changes and as such it's by no means unimportant because it's an "eye catcher where changes of .x degrees in global temps are becoming obvious.

this is not exclusive to sea-ice of course, glaciers and many other indicators exist but then sea-ice-extent is just easy for everyone to compare to let's say 30 years ago or even earlier.
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Dharma Rupa

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Re: The 2017 melting season
« Reply #4066 on: September 13, 2017, 01:42:52 AM »
i can't comment on your assumptions about the ice having little impact/importance to the rest of the global climate...

I don't think you understood where Nick was coming from.  Arctic Ice has about as much importance in climate change as a canary has to coal mining operations.

A-Team

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Re: The 2017 melting season
« Reply #4067 on: September 13, 2017, 04:08:08 AM »
The snow thickness time series below runs fro 15 Aug to 11 Sept at one frame per day using archived D0 initial states, then continues on as a forecast to Sep; 20th in 6 hour increments. This was fairly difficult to make given how the archive is organized, interface bugs in Panoply, and need for add-ons to basal Gimp but typifies value-added products that might suit forum interests better than the forecast-only perspective.

ESRL has not written up any documentation for this difficult-to-validate product so it is unclear to what extent it is satellite-based, a straight meteorological forecast, or coupled weather + ice + ocean. It may not consider snow drifts, melt, or rain-on-snow, in which case snow thickness per se would not yield thermal insulation or albedo. They have separate products for those though, as well as melt ponds.

We went through the summer believing snow cover was thicker and more persistent but without any concrete notion of how much the snow actually out there, what its condition was, and where it was distributed. ESRL may provide a sense of measurement accuracy down the road but for now it’s safe to say the snow is very thin, nowhere exceeding 20 cm. Note the storms that appear to sweep in from the south from the Svalbard area.
« Last Edit: September 13, 2017, 04:15:34 AM by A-Team »

Feeltheburn

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Re: The 2017 melting season
« Reply #4068 on: September 13, 2017, 06:39:42 AM »
i can't comment on your assumptions about the ice having little impact/importance to the rest of the global climate, just taking it as a statement and express my doubts, while even should that be as you say, the sea-ice is significantly impacted by what's going on on the planet as a whole (climate change etc.) and hence even should your assumptions be true and my doubts in vain, the ice is definitely one key indicator of ongoing changes and as such it's by no means unimportant because it's an "eye catcher where changes of .x degrees in global temps are becoming obvious.

this is not exclusive to sea-ice of course, glaciers and many other indicators exist but then sea-ice-extent is just easy for everyone to compare to let's say 30 years ago or even earlier.

Arctic is certainly an eye catcher. So are polar bears, although they have lost their luster as the "canary in the mine" since by all accounts their population is stable and they are not drowning or starving.
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jdallen

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Re: The 2017 melting season
« Reply #4069 on: September 13, 2017, 07:32:06 AM »
Arctic is certainly an eye catcher. So are polar bears, although they have lost their luster as the "canary in the mine" since by all accounts their population is stable and they are not drowning or starving.
<raised eyebrow> 
You may want to defend that statement ... in a different thread.
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Neven

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Re: The 2017 melting season
« Reply #4070 on: September 13, 2017, 07:45:27 AM »
Arctic is certainly an eye catcher. So are polar bears, although they have lost their luster as the "canary in the mine" since by all accounts their population is stable and they are not drowning or starving.
<raised eyebrow> 
You may want to defend that statement ... in a different thread.

I doubt he wants that, because then he will inevitably have to refer to paid climate denier sources (Crockford etc) and that will get him banned.  ::)
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F.Tnioli

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Re: The 2017 melting season
« Reply #4071 on: September 13, 2017, 12:23:48 PM »
Arctic is certainly an eye catcher. So are polar bears, although they have lost their luster as the "canary in the mine" since by all accounts their population is stable and they are not drowning or starving.
<raised eyebrow> 
You may want to defend that statement ... in a different thread.

I doubt he wants that, because then he will inevitably have to refer to paid climate denier sources (Crockford etc) and that will get him banned.  ::)
Indeed, i bet he doesn't, but merely because such people usually do not defend statements; not their style. Anyhow, are there any recent (last few days) news from PIOMAS? In particular, can we see current (up to say ~10th September) CAB volume dynamic? I think it's now good time to mention it in this topic, see what's cookin'.

uniquorn

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Re: The 2017 melting season
« Reply #4072 on: September 13, 2017, 01:01:52 PM »
Clearer weather close to the N pole today. Worldview 88.5N

nick

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Re: The 2017 melting season
« Reply #4073 on: September 13, 2017, 01:03:29 PM »
i can't comment on your assumptions about the ice having little impact/importance to the rest of the global climate, just taking it as a statement and express my doubts, while even should that be as you say, the sea-ice is significantly impacted by what's going on on the planet as a whole (climate change etc.) and hence even should your assumptions be true and my doubts in vain, the ice is definitely one key indicator of ongoing changes and as such it's by no means unimportant because it's an "eye catcher where changes of .x degrees in global temps are becoming obvious.

this is not exclusive to sea-ice of course, glaciers and many other indicators exist but then sea-ice-extent is just easy for everyone to compare to let's say 30 years ago or even earlier.

I just meant sea ice is a following indicator not a leading one. Obviously it's of interest to many different disciplines to study it and track it's behaviour but there are few where it's worth modelling a forecast of a few days.

The wavewatch model and, as far as I'm aware, the GFS, both only take the ice field at the start and treat it as fixed through out the forecast. It simply doesn't vary enough in that time scale to have noticeable effects (and in reality there is so little monitoring in the areas that would be affected that no one would notice anyway).

Archimid

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Re: The 2017 melting season
« Reply #4074 on: September 13, 2017, 03:05:32 PM »
An up tick from RSS North Polar anomaly.
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Shared Humanity

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Re: The 2017 melting season
« Reply #4075 on: September 13, 2017, 03:54:58 PM »
Eyeballing this chart, it would appear that this 'cold' Arctic summer which favored ice preservation was still anomalously warm.

FishOutofWater

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Re: The 2017 melting season
« Reply #4076 on: September 13, 2017, 05:05:48 PM »
There are multiple papers that show the presence of water, not ice, in the Barents sea is a predictor of weather in the fall and winter months because the heat affects the global atmospheric circulation. The intricate details of sea ice that we look at may not be significant but the big picture changes such as open water in the Barents sea and the "Atlantification" of the European side of the Arctic are affecting the weather and climate.

Sometimes we get too bogged down in the details and forget the big picture.

...And I really don't get the bashing of the ESRL. They are not keeping anyone else from publishing. They have a new web site and new models they have made public. We will see how their models work and evolve over the coming years.

Daniel B.

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Re: The 2017 melting season
« Reply #4077 on: September 13, 2017, 05:06:32 PM »
Arctic is certainly an eye catcher. So are polar bears, although they have lost their luster as the "canary in the mine" since by all accounts their population is stable and they are not drowning or starving.
<raised eyebrow> 
You may want to defend that statement ... in a different thread.

I doubt he wants that, because then he will inevitably have to refer to paid climate denier sources (Crockford etc) and that will get him banned.  ::)
Indeed, i bet he doesn't, but merely because such people usually do not defend statements; not their style. Anyhow, are there any recent (last few days) news from PIOMAS? In particular, can we see current (up to say ~10th September) CAB volume dynamic? I think it's now good time to mention it in this topic, see what's cookin'.
It is largely irrelevant.  Polar bear populations are only affected when there is too much ice (they have no open water in which to hunt) or there is too little (there is no floating ice from which they can hunt).  All ice conditions in between are quite similar, with little correlation between the two.  As long as sufficient ice and open water are both present, the bears are fine.

magnamentis

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Re: The 2017 melting season
« Reply #4078 on: September 13, 2017, 08:07:32 PM »
i can't comment on your assumptions about the ice having little impact/importance to the rest of the global climate, just taking it as a statement and express my doubts, while even should that be as you say, the sea-ice is significantly impacted by what's going on on the planet as a whole (climate change etc.) and hence even should your assumptions be true and my doubts in vain, the ice is definitely one key indicator of ongoing changes and as such it's by no means unimportant because it's an "eye catcher where changes of .x degrees in global temps are becoming obvious.

this is not exclusive to sea-ice of course, glaciers and many other indicators exist but then sea-ice-extent is just easy for everyone to compare to let's say 30 years ago or even earlier.

I just meant sea ice is a following indicator not a leading one. Obviously it's of interest to many different disciplines to study it and track it's behaviour but there are few where it's worth modelling a forecast of a few days.

The wavewatch model and, as far as I'm aware, the GFS, both only take the ice field at the start and treat it as fixed through out the forecast. It simply doesn't vary enough in that time scale to have noticeable effects (and in reality there is so little monitoring in the areas that would be affected that no one would notice anyway).

got what you mean, all about terms like so often, all good ;) :D
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cesium62

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Re: The 2017 melting season
« Reply #4079 on: September 14, 2017, 12:51:56 AM »
I just meant sea ice is a following indicator not a leading one.

I thought albedo was supposed to be important to climate.  Are you saying that painting my roof white was a complete waste of time?  ;D

And then struggling to pretend I'm on-topic...  I guess I'm saying that the high (relative to recent lows) 2017 late summer ice extent suggests that the planet might not have cooled off warmed up quite as quickly this year as it did in past years.  But the overall impact probably isn't that large so late in the season...
« Last Edit: September 14, 2017, 06:17:37 AM by cesium62 »

Tigertown

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Re: The 2017 melting season
« Reply #4080 on: September 14, 2017, 12:55:19 AM »
I don't think the planet cooled so much as the heat got stored. We probably will find this to be true when it shows back up when we least expect it.

miki

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Re: The 2017 melting season
« Reply #4081 on: September 14, 2017, 02:49:41 AM »
Ditto. It is weeks that I'm thinking quite the same thing.

I don't think the planet cooled so much as the heat got stored. We probably will find this to be true when it shows back up when we least expect it.

Michael Hauber

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Re: The 2017 melting season
« Reply #4082 on: September 14, 2017, 03:29:39 AM »
Arctic is certainly an eye catcher. So are polar bears, although they have lost their luster as the "canary in the mine" since by all accounts their population is stable and they are not drowning or starving.
<raised eyebrow> 
You may want to defend that statement ... in a different thread.

I doubt he wants that, because then he will inevitably have to refer to paid climate denier sources (Crockford etc) and that will get him banned.  ::)

Is WWF ok?  They seem to think polar bears are mostly stable (but vulnerable) at moment and population loss due to ice loss is something for future decades.
Climate change:  Prepare for the worst, hope for the best, expect the middle.

A-Team

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Re: The 2017 melting season
« Reply #4083 on: September 14, 2017, 03:09:10 PM »
Polar bears are flourishing.
Polar bears have taken a massive hit the last few years, notably in the Beaufort (fetus resorption), Chukchi (drowning), Hudson Bay (starving) and Barents (unable to reach denning sites). Inbreeding with brown bears? Selective advantages for life on ice become maladaptive on land meaning those genes will be rapidly lost, there's no turning back. Walruses though are far worse off already.

Arctic sea ice is a lagging indicator.
Might try "Arctic amplification" on google scholar before posting more nonsense. Arctic sea ice is the leading indicator of climate change. That's why we're here. As its current seasonal absence trends to imminent effective disappearance, it will have massive mid-latitude -- and indeed -- global consequences for climate.

Meanwhile, the zone north of the Barents is shape-shifting, translating, compactifying and melting. The first animation shows the moving 0-25% sea ice concentration line along with 4 floes over a static 13 Sep 17. The second shows open water along the Barents line; note the unexplained doughnut hole in the Laptev still persists but the opening towards the coast varies.
« Last Edit: September 14, 2017, 04:04:38 PM by A-Team »

Daniel B.

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Re: The 2017 melting season
« Reply #4084 on: September 14, 2017, 06:44:27 PM »
Polar bears are flourishing.
Polar bears have taken a massive hit the last few years, notably in the Beaufort (fetus resorption), Chukchi (drowning), Hudson Bay (starving) and Barents (unable to reach denning sites). Inbreeding with brown bears? Selective advantages for life on ice become maladaptive on land meaning those genes will be rapidly lost, there's no turning back. Walruses though are far worse off already.

Arctic sea ice is a lagging indicator.
Might try "Arctic amplification" on google scholar before posting more nonsense. Arctic sea ice is the leading indicator of climate change. That's why we're here. As its current seasonal absence trends to imminent effective disappearance, it will have massive mid-latitude -- and indeed -- global consequences for climate.

Meanwhile, the zone north of the Barents is shape-shifting, translating, compactifying and melting. The first animation shows the moving 0-25% sea ice concentration line along with 4 floes over a static 13 Sep 17. The second shows open water along the Barents line; note the unexplained doughnut hole in the Laptev still persists but the opening towards the coast varies.

Do you have data on those claims.  The PBSG lists the Barents, Hudson Bay and North Beaufort as Stable, while South Beaufort is in decline.  No data is available for the Chuhcki population.  Most recent estimates have increased total numbers.

http://pbsg.npolar.no/en/status/status-table.html

https://peerj.com/preprints/2737v3/

A-Team

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Re: The 2017 melting season
« Reply #4085 on: September 14, 2017, 07:13:11 PM »
supporting data on polar bear decline?
Sure do, wish I didn't. One thing that confuses people is adult bear counts vs recruitment, ie females having enough food and denning opportunities to bear enough adult replacement cubs that survive to reproductive age at weight. Off-topic here, be good to pursue in depth on a separate forum.

Try looking at the primary peer-reviewed papers by field biologists (as well as field journals), forget the Koch's twitter page (Crawford), the nonsense around goose eggs, the ABC special situation, and environmental charities pitching false hope to donors. The habitat situation for both bears and walruses is hopeless, don't kid yourself.

https://www.theatlantic.com/magazine/archive/2017/09/how-america-lost-its-mind/534231/
http://www.politico.com/magazine/story/2017/09/05/how-we-killed-expertise-215531

You can best find them at Pubmed among its 27,000,000 abstracts. Svalbard also tracks polar bears. The Siberian populations, the Russians may or may not be able to track them in remote locations.

https://www.ncbi.nlm.nih.gov/pubmed/advanced

Back on topic, here is the what the bears and walrus are up against quantitatively in the Chukchi, Beaufort, and Barents: way too much open water for way too much of the year. We've shown open water over bathymetry (ie walrus food diving depth) many times up-forum. Snow depth is also up-forum (10 cm doesn't work out for dens, that's why they head for certain Svalbard islands).







https://forum.arctic-sea-ice.net/index.php/topic,230.msg128925.html#msg128925 rest of post
« Last Edit: September 14, 2017, 07:41:43 PM by A-Team »

Tigertown

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Re: The 2017 melting season
« Reply #4086 on: September 14, 2017, 09:57:28 PM »
Thanks A-Team. I copied the text of your reply to  http://forum.arctic-sea-ice.net/index.php/topic,503.msg128952.html#msg128952

Another member had just posted a link, in this thread, to a very recent article that demonstrates that the future of the Polar Bear may indeed be much more bleak than many are portraying it to be.

Archimid

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Re: The 2017 melting season
« Reply #4087 on: September 15, 2017, 03:07:48 AM »

Do you have data on those claims.  The PBSG lists the Barents, Hudson Bay and North Beaufort as Stable, while South Beaufort is in decline.  No data is available for the Chuhcki population.  Most recent estimates have increased total numbers.

http://pbsg.npolar.no/en/status/status-table.html

https://peerj.com/preprints/2737v3/

The second link is Crockford in a non peer reviewed journal.  The first link seems legitimate in that it looks like real information. I have no clue haw Daniel B infers his claims from that. My first guess is that he just saw higher numbers in more recent years and that is enough to mislead many including himself.

This is terribly off topic, but obfuscated lies must be called out. Thanks TT for the link to continue this conversation in a proper thread.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

Tigertown

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Re: The 2017 melting season
« Reply #4088 on: September 15, 2017, 06:43:54 AM »

Rob Dekker

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Re: The 2017 melting season
« Reply #4089 on: September 15, 2017, 08:43:23 AM »
I don't think the planet cooled so much as the heat got stored. We probably will find this to be true when it shows back up when we least expect it.

I tend to think that heat never reached the surface this summer.
Remember that we had excessive land snow cover in May and June this year
http://climate.rutgers.edu/snowcover/chart_anom.php?ui_set=1&ui_region=nhland&ui_month=5
http://climate.rutgers.edu/snowcover/chart_anom.php?ui_set=1&ui_region=nhland&ui_month=6

That sure must have reflected a lot of sunlight, leading to thousands of TWs being reflected back to space, causing a rather cool summer.

A-Team

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Re: The 2017 melting season
« Reply #4090 on: September 15, 2017, 01:49:47 PM »
Here are the percentages of open water on Sept 14th for each of the last six years, based on 3.125 km resolution UH AMSR2.

Relative to what is possible (with Arctic Ocean as defined in the first frame as Inner Basin + upper Barents), the melt season peak on average is over halfway (51.4%) to a 'blue ocean' event.

Indeed, much of the Arctic Ocean is seasonally open already in yearly terms. Regions like the Chukchi experience a 'blue sea' event every year that lasts most of the year.

The lower image shows the six year average sea ice concentration for Sept 14th with 2017 outlined in yellow and 2012 in black.
« Last Edit: September 15, 2017, 06:09:07 PM by A-Team »

oren

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Re: The 2017 melting season
« Reply #4091 on: September 15, 2017, 02:23:52 PM »
https://www.theatlantic.com/magazine/archive/2017/09/how-america-lost-its-mind/534231/
A-Team I know this is veering wildly OT but thank you for this excellent (and hellishly long) article. It explained and tied together many things I kind of knew and felt but couldn't put my finger on.

Tigertown

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Re: The 2017 melting season
« Reply #4092 on: September 15, 2017, 02:48:10 PM »
Rob Dekker
Remember that we had excessive land snow cover in May and June this year
That sure must have reflected a lot of sunlight, leading to thousands of TWs being reflected back to space, causing a rather cool summer.
I am sure that helped to keep things from being as bad as they could have been. Nevertheless, the vast oceans have and will continue to absorb heat and store it, and it ends up in both polar regions.  Extended bottom melt beyond the regular season and increased winter storminess are some results.

Thomas Barlow

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Re: The 2017 melting season
« Reply #4093 on: September 15, 2017, 04:26:39 PM »
Judging by this, the Arctic Ocean itself (ignoring all peripherals such as CAA and Fram, etc., and thick ice crushed against land - "bits of ice stuck to land", as Wadhams puts it, re. a future 'Blue Ocean Event') looks like the overall ocean itself (ignoring fjords and coastal build-up) is about as bad a state as it gets for volume, maybe worst, at the start of freezing season.
« Last Edit: September 15, 2017, 04:37:21 PM by Thomas Barlow »

FishOutofWater

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Re: The 2017 melting season
« Reply #4094 on: September 15, 2017, 04:57:52 PM »
The late heavy snowfall and increased albedo was probably the largest factor leading to the cool summer over the central Arctic but the Arctic oscillation also stayed strongly positive. Was the cloudy, stormy weather in the central Arctic in summer linked to the cool stormy weather over Eurasia in the spring that caused the high albedo?

One thing to consider is that the north Atlantic ocean has been warmer than normal for months and the cool pool south of Greenland has been in decline as large quantities of warm salty water crossed from the Gulf Stream to the west coast of Europe.

I expect a very stormy fall and winter in the far north Atlantic and Eurasian Arctic seas based on the distribution of heat in the north Atlantic and another winter of a positive NAO. However, the weather is very good at doing unexpected things so we'll see.

Anyone know what happened to Judah Cohen and his blog?

Also, Slater's model did a good job of predicting the melting slowdown.

All in all, there's not much to celebrate in the improvement in the extent when volume is so low and warm salty water is flowing into the Arctic seas.  It's still a horrid situation for the polar bears and walruses. The scientists were right that the sea ice would not suddenly disappear after the extreme minimum in 2012, but volume wise there has not been a significant recovery.

uniquorn

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Re: The 2017 melting season
« Reply #4095 on: September 15, 2017, 05:01:36 PM »
The second animation shows what I think is MYI breaking from the pack in early June and avoiding the Fram Strait due to wind/current change. The first shows its eventual demise yesterday North of Svalbard. It appears not to have just broken into pieces but large parts also melted quickly. So do many of the floes around it. I recognise the compaction but the melt seems very quick here.

Thin ice covered with snow maybe? 
« Last Edit: September 16, 2017, 02:32:49 AM by uniquorn »

Archimid

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Re: The 2017 melting season
« Reply #4096 on: September 15, 2017, 05:20:27 PM »
Last year right about the end of the melting season, I thought that I could finally rest easy for a few years. I thought the arctic will at least follow the slow transition as described in the thread of that name. Then the 2016 freezing season happened.

A good recovery in this freezing season might "reset" the sea ice and buy us a decade or two of sea ice. If the recovery is over and another "warm" winter is in the works, we'll have a BOE over the next few years.
I am an energy reservoir seemingly intent on lowering entropy for self preservation.

uniquorn

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Re: The 2017 melting season
« Reply #4097 on: September 15, 2017, 08:38:31 PM »
5days out is unreliable, but as it's quiet here - GFS is predicting 978hpa

A-Team

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Re: The 2017 melting season
« Reply #4098 on: September 15, 2017, 11:44:56 PM »
5days out  GFS is predicting 978 hPa
Zack posted a nice animation of Arctic temperatures for Oct 2016 (ERA5, 2-m air temperature). Check out the surges of warmth through the Bering Strait and Barents areas.

https://twitter.com/i/web/status/908465802411569153

ESRL is back at it after a computer glitch knocking out Sept 12th. They're not seeing a whole lot of action coming in the next ten days. The differencing map shows some lineations in ice thickness that don't fully correspond to anything that noticeable in Sentinel-1 images.

The latest on working with ESRL in Panoply is pulled together over at the Developers Corner. (The real developer over at Nasa-Goddard has been very helpful explaining features via email.) Notably, the full file structure is provided in annotated form and some palette trickery explained. Choice of palette makes a very big difference in bringing out features; this can be explored very rapidly in Panoply.

https://forum.arctic-sea-ice.net/index.php/topic,1259.msg129050.html#msg129050

There's a host of potentially useful forecast products that we've yet to do much with, in addition to the daily gifs ESRL offers on their web page.

snow ai    snowfall rate
rain ai    rainfall rate
hi_h      ice thickness
hs_h     snow thickness

strength   compressive strength of sea ice
divu       divergence of sea ice velocity
Tsfc       surface temperature where sea ice

vocn       northward sea water velocity
uocn       eastward sea water velocity
vvel       northward sea ice velocity
uvel       eastward sea ice velocity   

meltl      lateral ice melt
meltb      basil ice melt
meltt      top ice melt
« Last Edit: September 16, 2017, 01:36:02 PM by A-Team »

Tigertown

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Re: The 2017 melting season
« Reply #4099 on: September 16, 2017, 12:36:19 AM »
5days out is unreliable, but as it's quiet here - GFS is predicting 978hpa
The ECMWF has it a little lower but in about the same position for the 20th. I think that it has been noted to be pretty reliable for a few days out. Not my cup of tea, reading these charts, but this looks like the makings for a strong gradient setup.