Support the Arctic Sea Ice Forum and Blog

Author Topic: The 2020/2021 freezing season  (Read 94628 times)

Glen Koehler

  • Frazil ice
  • Posts: 378
    • View Profile
  • Liked: 378
  • Likes Given: 806
Re: The 2020/2021 freezing season
« Reply #250 on: October 09, 2020, 08:37:18 PM »
<snip> Open water during the polar night *is* the positive feedback, the ultimate cause of Arctic amplification.
   But surely increased Long wave radiation outward from the ocean does result in increase of energy exported out of the system into space.  Not all of it is captured in the atmosphere to contribute to Arctic amplification.  Therefore, to some extent open water ---> increased LWR ---> is to some degree a negative feedback that works to stabilize Arctic energy balance.

    Granted all that LWR does not immediately leave the system, and can cause intermediate effects such as warming the overlying blanket of air and water vapor along the way.  Thus, there are feedbacks within the larger open water --- LWR feedback.  But the net effect of greater LWR emission has to result in more energy leaving the system eventually, and thus to some degree serve as a negative feedback.
« Last Edit: October 09, 2020, 08:48:52 PM by Glen Koehler »

I’M IN LOVE WITH A RAGER

  • New ice
  • Posts: 54
    • View Profile
  • Liked: 37
  • Likes Given: 10
Re: The 2020/2021 freezing season
« Reply #251 on: October 09, 2020, 10:05:19 PM »
Sure it might increase LWR emission, but I highly doubt it increases enough to reduce the energy in the system to a quantity lower than that of previous years where ice was already freezing in many of these anomalously warm areas. Even if all of the excess energy absorbed by the basin this summer left the system and it returned to an “average” heat content, wouldn’t it just return to average freezing progression, not somehow increase freezing? I fail to see how this energy SURPLUS is going to result in a DEFICIT come next melting season. If that were the case, warm water could freeze faster after being heated in the sun all day after being tossed into a freezer than room temperate water in the same freezer. Completely illogical. The sun-warmed cup might release more LWR because it has more energy to give, but it’s not going to pass the room temp cup in thermal energy content and reach a lower state under the same conditions and same timeframe. That’s not how thermodynamics works. Obviously the room temp cup starts freezing faster and freezes deeper in the same temporal stretch than the sun-warmed cup.

Glen Koehler

  • Frazil ice
  • Posts: 378
    • View Profile
  • Liked: 378
  • Likes Given: 806
Re: The 2020/2021 freezing season
« Reply #252 on: October 09, 2020, 11:32:32 PM »
     Of course adding heat is not going to make the Arctic get colder.  That is not what I said and is not implied by the term negative feedback.  My point was that an energy increase that results in more open water that results in increased LWR that results in increased energy lost from the system will have a negative feedback effect to partially counteract that initial energy addition.  That influence would act to partially revert back to the initial energy state but not go below it. 

     Unless a negative feedback is 100% effective (unlikely if not impossible without some other state change), it will not cause a system to even get all the way back to the initial state.  Adding energy to a system increases the energy in that system.  But a negative feedback acts to make the net gain in energy somewhat less than the initial value plus the added amount.  As the negative feedback acts to bring the system back towards and closer to the intial energy state,  the weaker that negative feedback becomes, so the system can't end up being less energetic than it was initially.  (And now somebody can point out some chemical system etc. where negative feedbacks can indeed overun and go below the initial state, but I can't see how that could possibly apply in a large complex system like the Arctic Ocean.)

     My point was that I think binntho was overreacting to his epiphany from A-Team.  Increased LWR can have some effects on air temperature or water vapor on its way toward space, but some portion of that additional long wave radiation will go into space, thus leaving the Arctic system.  That loss will cause energy loss from the system and, to some degree, that loss will function as a negative feedback on system energy level, i.e. warming.  Sorry if I am being pedantic, but your response so completely missed my point that I feel the need to be as explicit as possible.
« Last Edit: October 10, 2020, 02:46:28 AM by Glen Koehler »

I’M IN LOVE WITH A RAGER

  • New ice
  • Posts: 54
    • View Profile
  • Liked: 37
  • Likes Given: 10
Re: The 2020/2021 freezing season
« Reply #253 on: October 09, 2020, 11:53:45 PM »
For sure Glen, that makes sense. I definitely recognize that negative feedback loops are most often stabilizing/homeostatic in direction whereas positive feedback loops are most often accelerationary and divergent from baseline in direction. I wasn’t so much responding to what you were saying as much as some others in the thread who were implying the Arctic would be colder. I think you and I are on the same page, and I agree completely with what you said.

Glen Koehler

  • Frazil ice
  • Posts: 378
    • View Profile
  • Liked: 378
  • Likes Given: 806
« Last Edit: October 10, 2020, 02:42:09 AM by Glen Koehler »

kassy

  • Young ice
  • Posts: 2595
    • View Profile
  • Liked: 1205
  • Likes Given: 1066
Re: The 2020/2021 freezing season
« Reply #255 on: October 10, 2020, 12:08:30 AM »
FWIW, the "open water heading into the arctic night = GOOD" argument has always struck me as a violation of Occam's Razor: Less ice, more open water, later and later into the fall just does not seem "good" to me.
It’s not that it is good. It is that there are physical reasons (Stefan-Boltzmann Law) to expect that the more energy you make available now, the more energy will radiate out to space during the NH night.

The net effect is energy loss and therefore another factor to moderate, rather than precipitate, the decline of sea ice in the years to come.

A-Team is conflating this negative feedback effect that he, as scientist, knows well, with other atmospheric effects which are less clear and of more conjectural nature, to produce an overtly alarming picture.

The arctic night is always roughly similar yet we can have very different climate states as the past has shown.
Þetta minnismerki er til vitnis um að við vitum hvað er að gerast og hvað þarf að gera. Aðeins þú veist hvort við gerðum eitthvað.

jdallen

  • Young ice
  • Posts: 3254
    • View Profile
  • Liked: 535
  • Likes Given: 208
Re: The 2020/2021 freezing season
« Reply #256 on: October 10, 2020, 03:12:19 AM »
FWIW, the "open water heading into the arctic night = GOOD" argument has always struck me as a violation of Occam's Razor: Less ice, more open water, later and later into the fall just does not seem "good" to me.
It’s not that it is good. It is that there are physical reasons (Stefan-Boltzmann Law) to expect that the more energy you make available now, the more energy will radiate out to space during the NH night.

The net effect is energy loss and therefore another factor to moderate, rather than precipitate, the decline of sea ice in the years to come.

A-Team is conflating this negative feedback effect that he, as scientist, knows well, with other atmospheric effects which are less clear and of more conjectural nature, to produce an overtly alarming picture.
I'll disagree mildly with the last and bolded, and to a lesser degree with how you characterize A-Team's method.

I really can't remember in 7 years where he's seriously overstated an effect or mechanism.

Or even modestly for that matter.

Frankly, I think it is hard to understate the likely impact of warming of the Laptev, ESS, Barents and Kara in particular that took place during the melting season.

I think it's hard to understate the impact of the breakdown of stratification in the peripheral seas on the Atlantic side, along with the enormous influx of heat that's being pulled along by "Atlantification".

Other posters have correctly pointed out that outgoing black body radiation will not be able to dump the heat that's been accumulated, and is *still* being imported by southerlies pulling storms, heat and moisture into the basin from further south.

I think it bears serious watching, as my "hunch" at this point is we will see an extremely anemic refreeze, with a significant reduction in end of refreeze volume, even if those peripheral seas appear to refreeze robustly.  I think the portents for next year are very serious indeed.

Edit:  What we need, desperately, this winter:

- A strong polar vortex
- Crystal clear skies
- Minimal snow on the pack

I'm pessimistic about the probability of any of them.
« Last Edit: October 10, 2020, 03:20:46 AM by jdallen »
This space for Rent.

binntho

  • Nilas ice
  • Posts: 1534
    • View Profile
  • Liked: 544
  • Likes Given: 122
Re: The 2020/2021 freezing season
« Reply #257 on: October 10, 2020, 05:40:47 AM »
     My point was that I think binntho was overreacting to his epiphany from A-Team.  Increased LWR can have some effects on air temperature or water vapor on its way toward space, but some portion of that additional long wave radiation will go into space, thus leaving the Arctic system.  That loss will cause energy loss from the system and, to some degree, that loss will function as a negative feedback on system energy level, i.e. warming.  Sorry if I am being pedantic, but your response so completely missed my point that I feel the need to be as explicit as possible.

Not being big on epiphanies in general, perhaps I did overreact.

But it seems to me that a fundamental point is missing here, Glen, which is that all incoming energy from the sun radiates out to space again eventually.

Arctic amplification is an added warming of the Arctic atmosphere that is caused by extra heat being released from the open ocean, whether by conduction or radiation. But all the heat released will radiate out to space eventually. Atmospheric green-house gases delay the release of energy, but do not stop it, causing the global atmospheric temperature to be almost 30 degrees higher than it would otherwise be (and rising). Local Arctic cloud blanketing adds significantly to delaying the energy on its way out to space but does not stop the energy from radiating out eventually.

Arctic amplification indicates an imbalance in the distribution of Arctic insolation energy (as do other amplifications, such as dry land amplification and continental amplification). Arctic amplification is caused by the energy added during peak insolation being released *locally* rather than joining the global oceanic circulation.

Increased LWR out to space is therefore a proxy for increased atmospheric temperatures. Arctic amplification implies more LWR radiation out to space. Increased LWR is a result of Arctic amplification.

Long Wave Radiation is thus not a negative feedback at all. It simply reflects incoming energy. The delay in the escape of energy from the atmosphere is what raises atmospheric temperatures, but the amount of energy released will always match the incoming (in the long run of course, in a warming world some energy is retained until a balance is re-established).
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

Aluminium

  • Grease ice
  • Posts: 767
    • View Profile
  • Liked: 677
  • Likes Given: 391
Re: The 2020/2021 freezing season
« Reply #258 on: October 10, 2020, 07:33:35 AM »
LWR is main negative feedback which stabilizes temperature on the Earth and prevents violation of the second law of thermodynamics. Warmer -> more LWR -> cooling. Cooler -> less LWR -> warming. Increased LWR can be a result of positive feedback but it provides negative feedback itself.

Aluminium

  • Grease ice
  • Posts: 767
    • View Profile
  • Liked: 677
  • Likes Given: 391
Re: The 2020/2021 freezing season
« Reply #259 on: October 10, 2020, 07:38:25 AM »
October 5-9.

2019.

binntho

  • Nilas ice
  • Posts: 1534
    • View Profile
  • Liked: 544
  • Likes Given: 122
Re: The 2020/2021 freezing season
« Reply #260 on: October 10, 2020, 07:49:27 AM »
LWR is main negative feedback which stabilizes temperature on the Earth and prevents violation of the second law of thermodynamics. Warmer -> more LWR -> cooling. Cooler -> less LWR -> warming. Increased LWR can be a result of positive feedback but it provides negative feedback itself.

Perhaps we need to find a better definition of terms here. Feedback is when something is fed back into the system, and outgoing LWR radiation is obviously not fed back. So by that definition it is not a feedback, neither negative nor positive.

Solar insolation is not a feedback either. It is an input. Outgoing LWR is an output.

Increasingly open waters during maximum insolation are a result of global warming, and by themselves cause even faster warming. A typical postive feedback. And then some people would like to say that this is countered by the increased outgoing LWR caused by the same open waters going into the polar night, effectively saying that open waters are a positie feedback during peak insolation, and a negative feedback during the polar night.

But this is a misunderstanding. Open waters going into the polar night are the mechanism by which the added energy during peak insolation is released back to the atmosphere, thereby contributing to Arctic Amplification. All energy released to the atmosphere ends up leaving into space via LWR amyway, the difference here being where the energy is released, i.e in the Arctic as opposed to elsewhere.

And this turns the open waters into a positive feedback during the polar night. Without the open waters, the insulating blanket would be much thinner and the amount of energy in the atmosphere would be much less. The ice would freeze much faster and become thicker. But because of the open waters, the energy added into the ocean during peak insolation is allowed to escape into the atmosphere, raising humidity and temperatures. The fact that it eventually escapes into space is meaningless in this context.
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

S.Pansa

  • Frazil ice
  • Posts: 171
    • View Profile
  • Liked: 42
  • Likes Given: 5
Re: The 2020/2021 freezing season
« Reply #261 on: October 10, 2020, 08:56:50 AM »
I guess we are veering way off topic here but here is a quote from a standard textbook on the basic science of global warming, David Archers "Global Warming. Understanding the forecast".

In chapter 7, p 73 f he writes:
Quote
A feedback is a loop of cause and effect (Figure 7-1). At the center of a feedback is a state
variable. The state variable in many of the climate feedback loops in this book is the average
temperature of the Earth. To see a feedback in action, drive the temperature a bit by changing
some external factor, like the intensity of the sun. A positive feedback makes the temperature
change larger than it would have been without the feedback, amplifying the temperature change.
A negative feedback counteracts some of the external forcing, tending to stabilize the state
variable. ... A negative feedback is a stabilizer. The drain in the kitchen sink analogy has a
negative feedback to the water level. ... A positive feedback is an amplifier.

He also names a few examples, explained in the attached figure 7-1

An the NASA writes
Quote
Climate feedbacks: processes that can either amplify or diminish the effects of climate forcings. A feedback that increases an initial warming is called a "positive feedback." A feedback that reduces an initial warming is a "negative feedback."

What I find strange is - I am with aslan here - that some people are calling well known atmospheric effects "less clear and of more conjectural nature". The greenhouse effect would be totally different without the influence of clouds, water vapor, lapse rate, moist convection ... imho they are not conjectural but basic (basic text-book stuff actually).

Just one example, again  from David Archer (p 62 and fig 6-5):
Quote
Even when averaging out the seasonal cycle, the radiative energy budget of a single spot on the surface of the Earth is still probably way out of balance, because heat energy is redistributed around the Earth’s surface by wind and water currents (Figure 6-5). There is a net influx of heat in the tropics as sunlight brings in energy faster than the outgoing IR. It does not get hot enough in the tropics for outgoing IR to balance the incoming sunlight locally. Heat is carried into the cooler high latitudes by warm winds and ocean currents. In high latitudes, the Earth vents the excess tropical heat as excess radiative heat loss to space.

Did I say I think I am going off-topic?  :-[
« Last Edit: October 10, 2020, 09:03:29 AM by S.Pansa »

binntho

  • Nilas ice
  • Posts: 1534
    • View Profile
  • Liked: 544
  • Likes Given: 122
Re: The 2020/2021 freezing season
« Reply #262 on: October 10, 2020, 09:40:58 AM »
Thanks for that input S. Pansa. As to whether we are off topic or not ... it is topical in the sense that we are discussing things that are happening during this freezing season. But then again, it is a discussion of fundamentals which perhaps should belong elsewhere.

As for how we define feedbacks - I do not agree with David Archers' inclusion of the drain in the kitchen sink. It is not a negative feedback, it is simply the output of the system. Same goes for the spout, it is not a positive feedback, it is the input to the system.

A feedback has to feed back! There must be a re-entry of some sort, a circular causation. In the sink example, a positive feedback would be something that caused the water level to rise faster than the inflow of water could explain on its own and should be caused by the inflow of water. A pressure seal that becomes more efficient with increased pressure could be an example of a positive feedback. In scenario A, the system is in equilibrium. In scenario B, the inflow rate has increased and the water level rises to compensate, but the positive feedback of the pressure seal leads to scenario C where the equilibrium level is pushed higher than would otherwise have been the case based on the increased input alone.

In our case, the positive feedback is the presence of open water which is caused by increased temperatures, but at the same time causes temperatures to rise even further in a limited area (i.e. Arctic amplification). The mechanism involved is lower albedo during peak insolation, and a commensurately larger loss of heat during autumn and winter combined with a blanketing effect. Any increase in outgoing LWR simply shows that the positive feedback is active!
because a thing is eloquently expressed it should not be taken to be as necessarily true
St. Augustine, Confessions V, 6

oren

  • Moderator
  • First-year ice
  • Posts: 6423
    • View Profile
  • Liked: 2388
  • Likes Given: 2042
Re: The 2020/2021 freezing season
« Reply #263 on: October 10, 2020, 10:19:40 AM »
Folks, an interesting discussion but when too long it becomes off-topic. I suggest we have covered the issue well and there seems to be a general agreement - the extra added energy in the system (from sun-albedo and from lower latitude transport) is (mostly) released during winter, with open water serving as a main release mechanism. This release is causing climate-changing winter effects, leading to higher temps and lower overall ice growth. The mechanism is not expected to lead to a colder winter or thicker ice, compared with a normal year. Further discussion can be taken elsewhere, where it will better survive the test of time.

Also another request, please don't start discussing specific posters. Discuss science, not persons.

BornFromTheVoid

  • Nilas ice
  • Posts: 1250
    • View Profile
  • Liked: 579
  • Likes Given: 199
Re: The 2020/2021 freezing season
« Reply #264 on: October 10, 2020, 01:03:26 PM »
Slow animation from the last 5 days.

I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

Freegrass

  • Nilas ice
  • Posts: 1640
  • None but ourselves can free our minds...
    • View Profile
  • Liked: 522
  • Likes Given: 765
Re: The 2020/2021 freezing season
« Reply #265 on: October 10, 2020, 01:48:38 PM »
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Wind + Temp @ 850hPa
Large GiFS!

A fresh dash of warm air coming in from the Pacific it seems...
Now let's pray...

If the science don't fit our beliefs, we pray to God and cuddle up in our own delusional fantasy where everything makes sense again...

gandul

  • Grease ice
  • Posts: 765
    • View Profile
  • Liked: 184
  • Likes Given: 10
Re: The 2020/2021 freezing season
« Reply #266 on: October 10, 2020, 01:54:35 PM »
In one week we’ll have the perfect radiator to space. Warm stirred open ocean under a wide open dark sky.

gandul

  • Grease ice
  • Posts: 765
    • View Profile
  • Liked: 184
  • Likes Given: 10
Re: The 2020/2021 freezing season
« Reply #267 on: October 10, 2020, 02:26:48 PM »
Just to briefly respond in general, I was not saying it is an overwhelming effect but something that helps the Arctic ice loss not to be faster than it really is. Let’s not willfully count only with the warming-enhancing effects.

Also @binntho: there is an extra delta heat that can be lost if open wide ocean is being stirred, subsurface ocean heat that otherwise would remain buried at least until next season, it’s not just heat lost due to extra temperature, it’s the delta heat loss caused by ice loss. It is an internal restorative force. If there was no delta extra heat loss due to ice loss, it wouldn’t be a feedback.
What you describe is not, I agree.
« Last Edit: October 10, 2020, 02:33:26 PM by gandul »

BornFromTheVoid

  • Nilas ice
  • Posts: 1250
    • View Profile
  • Liked: 579
  • Likes Given: 199
Re: The 2020/2021 freezing season
« Reply #268 on: October 10, 2020, 03:42:04 PM »
I decided to measure the changes in the ice edge position, starting at the daily minimum.
For now, it's the ice edge position (first instance of open water) or where the ice is at its maximum extent (such as N of Greenland or along sections of the Arctic ocean coasts in some years) that's measured. Measurements are done every 5 degrees, but also grouped for stats on edges facing individual seas.

(Ideally, I could do something like this for every day of the year, all years, but that's gonna be some way down the road when my python skills have improved a lot!)

I've only done 79 to 89 so far, and the closest ice edge position, by far, was in 1979, at 678 km at 50 degrees east.
On average, the minimum with the closest ice edge position was 1984, averaging 1330 km.
I'll get it updated to 2020 during the week, hopefully, and do the maxima after that. For now, here's just a sample with 1979 to 1989.

Comments/suggestion welcome as always.
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

Wildcatter

  • New ice
  • Posts: 61
    • View Profile
  • Liked: 39
  • Likes Given: 48
Re: The 2020/2021 freezing season
« Reply #269 on: October 10, 2020, 04:24:54 PM »
Haha, yeah I saw that forecast (for 17th). Look at those isobars  :P 

So, in about 4 days, euro and GFS in pretty good agreement, high sets up and brings some heavy winds and warmer temps across the Chukchi and siberian seas, some moisture, goes on for about 4 more days (so 8 days from now), models start to diverge there. If that comes to pass, I imagine it has some stalling effect on ice re-growth. Maybe not. I'll go with an unequivocal, "probably". Ironclad.

GFS has 4.5-4.8C Arctic temp anomalies for the 13th-17th (relative to '79-2000), that open water pretty extreme anomalies. I just use climatereanalyzer hourly forecast for temp anomalies, uses GFS, can go see if it you're curious. https://climatereanalyzer.org/  on left-hand side, click "hourly forecast", change "Forecast Model" dropdown to GFS global, "Map Area" to Arctic, and "Variable Dropdown" to 2m temp anomaly, and there's some other variables you can peruse at your leisure.

And just as a reference, to throw some freeze season extent numbers out there, a comparison to 2019 on October 17th, just picked that day because it was top of mind

8 days worth of measurements (km2)
On 17th: 2019 = 5.24 million
Today: 2020 = 4.47 million
2020 has to average ~96,000 extent gain a day to recover past 2019s low (or 2020 will be lowest)

Might be pretty tough if that setup plays out. Just something to keep an eye on, and models could change completely in a few days so there's the disclaimer.  :D

gerontocrat

  • First-year ice
  • Posts: 9632
    • View Profile
  • Liked: 3810
  • Likes Given: 29
Re: The 2020/2021 freezing season
« Reply #270 on: October 10, 2020, 04:46:32 PM »
The 10 year average daily gain will reach the maximum of well over 125k per day from about the 16th of October.

Trouble is, some years are late re-freeze, some early.
"Para a Causa do Povo a Luta Continua!"
"And that's all I'm going to say about that". Forrest Gump
"Damn, I wanted to see what happened next" (Epitaph)

Tor Bejnar

  • Young ice
  • Posts: 3724
    • View Profile
  • Liked: 653
  • Likes Given: 440
Re: The 2020/2021 freezing season
« Reply #271 on: October 10, 2020, 04:51:37 PM »
Could somebody graph extent data deltas (difference from minimum for that year) from Sept. 15 onward?  My guess is that more recent years' data will have a lower slope than earlier years.  2020 appears to have very slow growth.

Thanks in advance (and hoping ...)  [edit:  like what Gero just posted, only starting on Sept. 15]
Arctic ice is healthy for children and other living things.

dosibl

  • New ice
  • Posts: 44
    • View Profile
  • Liked: 6
  • Likes Given: 0
Re: The 2020/2021 freezing season
« Reply #272 on: October 10, 2020, 05:09:10 PM »
Looking at the average sea level pressure anomaly as a proxy for clearer skies during the peak AWP dates in the Laptev / ESS (~6/15-8/1), lines up decently with the large SST anomaly there now. Will be interesting to see what happens there over the next month.

Comradez

  • New ice
  • Posts: 87
    • View Profile
  • Liked: 31
  • Likes Given: 0
Re: The 2020/2021 freezing season
« Reply #273 on: October 10, 2020, 05:48:12 PM »
Interesting figures, S.Pansa!  Is there a particular reason why, in Figure 6-5, the incoming and outgoing radiation don't seem to net to zero globally?  (Just eyeballing it, it looks like there's no way the areas under the curves match).

Peter Ellis

  • Grease ice
  • Posts: 619
    • View Profile
  • Liked: 34
  • Likes Given: 14
Re: The 2020/2021 freezing season
« Reply #274 on: October 10, 2020, 07:04:18 PM »
Interesting figures, S.Pansa!  Is there a particular reason why, in Figure 6-5, the incoming and outgoing radiation don't seem to net to zero globally?  (Just eyeballing it, it looks like there's no way the areas under the curves match).
Remember that the total area from (say) 0-10 degrees north is MUCH larger than the area from 80-90 degrees north.

Freegrass

  • Nilas ice
  • Posts: 1640
  • None but ourselves can free our minds...
    • View Profile
  • Liked: 522
  • Likes Given: 765
Re: The 2020/2021 freezing season
« Reply #275 on: October 11, 2020, 01:32:34 PM »
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
Now let's pray...

If the science don't fit our beliefs, we pray to God and cuddle up in our own delusional fantasy where everything makes sense again...

oren

  • Moderator
  • First-year ice
  • Posts: 6423
    • View Profile
  • Liked: 2388
  • Likes Given: 2042
Re: The 2020/2021 freezing season
« Reply #276 on: October 11, 2020, 01:42:04 PM »
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
The central Beaufort should finally see surface freeze, and the tail should lose its shape (already begun yesterday), thanks to the very low temps. However big trouble is coming from Laptev and the ESS, with some temps even rising above zero. So not much growth this coming week. 2020 will probably be lowest on record in both area and extent.

uniquorn

  • Young ice
  • Posts: 2831
    • View Profile
  • Liked: 1290
  • Likes Given: 258
Re: The 2020/2021 freezing season
« Reply #277 on: October 11, 2020, 11:02:23 PM »
Just a hint of coastal refreeze in parts of the Lena delta on worldview. Quite a change from sep23. (click for ani)

polarview, oct10

Oddly enough, further north it still looks like melt season.
« Last Edit: October 11, 2020, 11:11:54 PM by uniquorn »

Pagophilus

  • Grease ice
  • Posts: 533
    • View Profile
  • Liked: 300
  • Likes Given: 441
Re: The 2020/2021 freezing season
« Reply #278 on: October 11, 2020, 11:41:28 PM »
Just a hint of coastal refreeze in parts of the Lena delta on worldview. Quite a change from sep23. (click for ani)

polarview, oct10

Oddly enough, further north it still looks like melt season.
Maybe because there is a freshwater layer capping the sea around the Lena's mouths, but saltier water at the surface further out? 
Thanks for these images. 

SimonF92

  • Frazil ice
  • Posts: 325
    • View Profile
  • Liked: 139
  • Likes Given: 68
Re: The 2020/2021 freezing season
« Reply #279 on: October 12, 2020, 01:00:31 AM »
Cold air is blowing off the continent, its just colder closer to shore
Bunch of small python Arctic Apps:
https://github.com/SimonF92/Arctic

Aluminium

  • Grease ice
  • Posts: 767
    • View Profile
  • Liked: 677
  • Likes Given: 391
Re: The 2020/2021 freezing season
« Reply #280 on: October 12, 2020, 07:37:41 AM »
October 7-11.

2019.

morganism

  • Frazil ice
  • Posts: 256
    • View Profile
  • Liked: 53
  • Likes Given: 1
Re: The 2020/2021 freezing season
« Reply #281 on: October 12, 2020, 08:14:18 AM »
edit: oops

uniquorn

  • Young ice
  • Posts: 2831
    • View Profile
  • Liked: 1290
  • Likes Given: 258
Re: The 2020/2021 freezing season
« Reply #282 on: October 12, 2020, 11:33:01 AM »
Thanks for the SMOS post. As we suspected, all that MYI exported to the Beaufort tail has nearly melted out, and will give no resilience against next year's melting season.
It effectively amounts to open water except energy to refreeze further area is closer to zero.
For practical purposes Beaufort sea is free of MYI facing the refreeze season

It will be interesting to see what the NSIDC ice age update looks like. Here is a polarview S1A of the stalwart MYI floe at the centre of the amsr2 inset (awi v103). It's looking somewhat rounded, so has probably not had an easy time during the melting season.   ~300km2, maybe it will show up on cryosat2 if it doesn't drift too quickly.
Quote
CryoSat-2 will achieve improved spatial resolution of 250 m in the along-track direction using the Synthetic Aperture technique.
https://earth.esa.int/web/guest/missions/esa-operational-eo-missions/cryosat/overview
« Last Edit: October 12, 2020, 04:00:57 PM by uniquorn »

Freegrass

  • Nilas ice
  • Posts: 1640
  • None but ourselves can free our minds...
    • View Profile
  • Liked: 522
  • Likes Given: 765
Re: The 2020/2021 freezing season
« Reply #283 on: October 12, 2020, 01:46:17 PM »
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Wind + Temp @ 850hPa
Wind @ 250hPa
Large GiFS!

High pressure in the Arctic with high temperatures and lots of the greenhouse gas moisture to keep all that heat in... How unusual is that for this time of year?
« Last Edit: October 12, 2020, 01:53:40 PM by Freegrass »
Now let's pray...

If the science don't fit our beliefs, we pray to God and cuddle up in our own delusional fantasy where everything makes sense again...

harpy

  • Frazil ice
  • Posts: 297
    • View Profile
  • Liked: 89
  • Likes Given: 23
Re: The 2020/2021 freezing season
« Reply #284 on: October 12, 2020, 03:02:47 PM »
Thanks for that input S. Pansa. As to whether we are off topic or not ... it is topical in the sense that we are discussing things that are happening during this freezing season. But then again, it is a discussion of fundamentals which perhaps should belong elsewhere.

As for how we define feedbacks - I do not agree with David Archers' inclusion of the drain in the kitchen sink. It is not a negative feedback, it is simply the output of the system. Same goes for the spout, it is not a positive feedback, it is the input to the system.

A feedback has to feed back! There must be a re-entry of some sort, a circular causation. In the sink example, a positive feedback would be something that caused the water level to rise faster than the inflow of water could explain on its own and should be caused by the inflow of water. A pressure seal that becomes more efficient with increased pressure could be an example of a positive feedback. In scenario A, the system is in equilibrium. In scenario B, the inflow rate has increased and the water level rises to compensate, but the positive feedback of the pressure seal leads to scenario C where the equilibrium level is pushed higher than would otherwise have been the case based on the increased input alone.

In our case, the positive feedback is the presence of open water which is caused by increased temperatures, but at the same time causes temperatures to rise even further in a limited area (i.e. Arctic amplification). The mechanism involved is lower albedo during peak insolation, and a commensurately larger loss of heat during autumn and winter combined with a blanketing effect. Any increase in outgoing LWR simply shows that the positive feedback is active!


Excellent post, thank you.

The Walrus

  • Grease ice
  • Posts: 787
    • View Profile
  • Liked: 106
  • Likes Given: 63
Re: The 2020/2021 freezing season
« Reply #285 on: October 12, 2020, 03:23:07 PM »
Yes, much of what people refer to as feedback is not so (even though the influence the system).  Cloud cover is a prime example.  Blocking incoming solar radiation during the day is not feedback, but reflecting radiation earthward at night is.  However, changing the cloud cover, due to climate change would be a feedback.  Same with the open water.

Freegrass

  • Nilas ice
  • Posts: 1640
  • None but ourselves can free our minds...
    • View Profile
  • Liked: 522
  • Likes Given: 765
Re: The 2020/2021 freezing season
« Reply #286 on: October 13, 2020, 01:46:47 PM »
Latest Five Day Forecast
Wind + Temp @ Surface
Large GiF!
Now let's pray...

If the science don't fit our beliefs, we pray to God and cuddle up in our own delusional fantasy where everything makes sense again...

gandul

  • Grease ice
  • Posts: 765
    • View Profile
  • Liked: 184
  • Likes Given: 10
Re: The 2020/2021 freezing season
« Reply #287 on: October 13, 2020, 02:00:18 PM »
Impressive waves predicted for this saturday, being the Arctic in October (ECMWF)
« Last Edit: October 13, 2020, 02:11:17 PM by gandul »

Positive retroaction

  • New ice
  • Posts: 50
    • View Profile
  • Liked: 28
  • Likes Given: 148
Re: The 2020/2021 freezing season
« Reply #288 on: October 13, 2020, 02:58:51 PM »
Could the edge on the laptev / ESS side, which is already struggling to progress, decrease?
It will also depend on the frequency of the waves, right?
Sorry, excuse my bad english

gandul

  • Grease ice
  • Posts: 765
    • View Profile
  • Liked: 184
  • Likes Given: 10
Re: The 2020/2021 freezing season
« Reply #289 on: October 13, 2020, 07:43:54 PM »
Could the edge on the laptev / ESS side, which is already struggling to progress, decrease?
It will also depend on the frequency of the waves, right?
No idea, I’d say it’s too cold but who knows.

But it’s the perfect weather to unbury lots of heat, at least the first few meters of ocean sub-surface are susceptible to waves caused by 20 kt winds or so, and quite a lot of fetch to generate some mechanical energy that gets deep a few meters.

Actually the weather has not been quiet at all since september so this is an ongoing situation.

A-Team

  • Young ice
  • Posts: 2737
    • View Profile
  • Liked: 680
  • Likes Given: 34
Re: The 2020/2021 freezing season
« Reply #290 on: October 13, 2020, 10:58:55 PM »
Quote
No idea, I’d say it’s too cold
I would say it's far too warm between the ice pack and the entire Siberian side to even be considering refreezing inroads by Nov 1st. The southern limit of ice has hardly budged since Oct 1st (magenta line) so still has 1200 km to go. The sea surface temperature anomalies are remarkable today and even out nine days to Oct 22nd, per Mercator Ocean.

An immense volume of warm water is still several degrees above the freezing point of salt water from the surface to a depth of 30+m, again out to Oct 22nd, making for some 90,000 cubic km of sea water needing to be cooled (if vertically mixed) by air having only a thousandth the specific heat capacity.

A delayed freeze has significant consequences in terms of thinner, brine pockety ice by spring like it did last year in the wake of the extreme TransPolar Drift

The Chukchi is even slated to get warmer towards the end of the month from incoming advection of yet warmer waters from the Bering Sea. At this rate, the southern Chukchi will remain open water into early or even mid January.

Weakening of Cold Halocline Layer Exposes Sea Ice to Oceanic Heat in the Eastern Arctic Ocean
IV Polyakov, T Rippeth et al
J. Climate (2020) 33 (18): 8107–8123.
https://journals.ametsoc.org/jcli/article/33/18/8107/353233 free full

"The upward release of AW heat is regulated by the stability of the overlying halocline, which we show has weakened substantially in recent years. Shoaling of the AW has also contributed, with observations in winter 2017–18 showing AW at only 80 m depth, just below the wintertime surface mixed layer, the shallowest in our mooring records. The weakening of the halocline for several months at this time implies that AW heat was linked to winter convection associated with brine rejection during sea ice formation. This resulted in a substantial increase of upward oceanic heat flux during the winter season, from an average of 3–4 W m−2 in 2007–08 to >10 W m−2 in 2016–18. This seasonal AW heat loss in the eastern EB is equivalent to a more than a twofold reduction of winter ice growth. These changes imply a positive feedback as reduced sea ice cover permits increased mixing, augmenting the summer-dominated ice-albedo feedback."

Greater role for Atlantic inflows on sea-ice loss in the Eurasian Basin of the Arctic Ocean
IV Polyakov et al
Science  21 Apr 2017
https://science.sciencemag.org/content/356/6335/285.full  free full

Arctic sea ice is being increasingly melted from below by warming Atlantic water
Tom Rippeth  Prof Physical Oceanography, Bangor ME
September 18, 2020  popularization by co-author of two papers above
https://theconversation.com/arctic-sea-ice-is-being-increasingly-melted-from-below-by-warming-atlantic-water-144106

"What’s causing this decline in minimum sea ice extent? The short answer is our changing climate. But the more specific answer is that Arctic sea ice is increasingly being thinned not just by warm air from above but by ever-warmer waters from below.

In fact, in a recently published scientific study my colleagues and I looked at why sea ice was melting in the eastern Arctic Ocean and showed that the influence of heat from the interior of the ocean has now overtaken the influence of the atmosphere.

While atmospheric heat is the dominant reason for melting in the summer, it has little influence during the cold dark polar winter. However, the ocean warms the ice from below year-round. Our new research shows that this influence has more than doubled over the past decade or so and is now equivalent to the melting of nearly a meter thickness of sea ice each year.

Further to the east, this warm water has been isolated from the sea surface and so sea ice by a layer of colder, fresher water. However, as the heat blob is getting warmer and moving closer to the surface its influence is now spreading eastwards through the Arctic.

In a second scientific paper we showed that currents in the upper Arctic ocean were increasing, which when combined with declining sea ice and the weakening of the boundaries between layers of warm and cold water, was potentially stirring more warm water from the heat blob towards the surface. The combined impact is a new back and forth relationship between sea ice and ocean heat which could lead to a new ocean climate state in the eastern Arctic Ocean."
« Last Edit: October 14, 2020, 01:33:12 AM by A-Team »

uniquorn

  • Young ice
  • Posts: 2831
    • View Profile
  • Liked: 1290
  • Likes Given: 258
Re: The 2020/2021 freezing season
« Reply #291 on: October 13, 2020, 11:31:10 PM »
It's time to go to night vision using worldview terra modis viirs brightness temperature band 15 (night or day) https://go.nasa.gov/2FpoLVd
Today's image showing the effect of wind driven drift on the Atlantic front (awi amsr2 v103 from yesterday inset)

Quote
The VIIRS Brightness Temperature, Band I5 Night layer is the brightness temperature, measured in Kelvin (K), calculated from the top-of-the-atmosphere radiances. It does not provide an accurate temperature of either clouds nor the land surface, but it does show relative temperature differences which can be used to distinguish features both in clouds and over clear land. It can be used to distinguish land, sea ice, and open water over the polar regions during winter (in cloudless areas).

The VIIRS Brightness Temperature layer is calculated from VIIRS Calibrated Radiances (VNP02) and is available from the joint NASA/NOAA Suomi National Polar orbiting Partnership (Suomi NPP) satellite. The sensor resolution is 375m, the imagery resolution is 250m, and the temporal resolution is daily.

Only one Polarview S1B of the area today.

It's also worth looking at relatively cloud free sea ice north of the CAA today. High winds are forecast for this area too over the next couple of days.      https://go.nasa.gov/3dAMzSN
« Last Edit: October 14, 2020, 12:11:47 AM by uniquorn »

FishOutofWater

  • Grease ice
  • Posts: 874
    • View Profile
  • Liked: 501
  • Likes Given: 179
Re: The 2020/2021 freezing season
« Reply #292 on: October 14, 2020, 12:18:53 AM »
The ECMWF forecasts that ice will thicken rapidly on the Canadian side of the central Arctic when the high pressure sets up there. However, the strong winds over the warm waters on the Siberian side will enhance Fram export and reduce ice edge growth. Moreover, skies are likely to be cloudy and possibly stormy on the Siberian side of the pole because the ice edge will be a baroclinic zone and warm water quickly produces clouds when nights get cold.

https://www.ecmwf.int/en/forecasts/charts/catalogue/medium-snow-sic?facets=undefined&time=2020101300,228,2020102212&projection=classical_arctic

A-Team

  • Young ice
  • Posts: 2737
    • View Profile
  • Liked: 680
  • Likes Given: 34
Re: The 2020/2021 freezing season
« Reply #293 on: October 14, 2020, 12:59:44 AM »
Quote
the ice edge is a baroclinic zone --> clouds --> heat retained
Right. Here's a very nice display of historic October extent on the Siberian side that really brings out the unprecedented situation of the current season. The trend is to open earlier, open more, freeze later in this region of the Arctic Ocean.

Yet another fabulous graphic from @zlabe ... such an effective color scheme! Needs an inset map that defines 'Siberian Arctic' though. See above for closely related nice graphic from Geronto.)
« Last Edit: October 14, 2020, 01:37:19 AM by A-Team »

Aluminium

  • Grease ice
  • Posts: 767
    • View Profile
  • Liked: 677
  • Likes Given: 391
Re: The 2020/2021 freezing season
« Reply #294 on: October 14, 2020, 06:10:39 AM »
October 9-13.

2019.

Positive retroaction

  • New ice
  • Posts: 50
    • View Profile
  • Liked: 28
  • Likes Given: 148
Re: The 2020/2021 freezing season
« Reply #295 on: October 14, 2020, 09:57:37 AM »
Quote
the ice edge is a baroclinic zone --> clouds --> heat retained
Right. Here's a very nice display of historic October extent on the Siberian side that really brings out the unprecedented situation of the current season. The trend is to open earlier, open more, freeze later in this region of the Arctic Ocean.

Yet another fabulous graphic from @zlabe ... such an effective color scheme! Needs an inset map that defines 'Siberian Arctic' though. See above for closely related nice graphic from Geronto.)
Yes, thanks for this excellent représentation
If I understand correctly, from now on and for 2 weeks, we arrive in the zone of strong growth of 2012, and of average maximum increase of the other years as well. what will happen in 2020 during these 2 weeks is likely to be really interesting to follow, will the increase simply be delayed (which is already significant), or will it also be reduced because of the strong temperature anomalies?
the sea between the central pack and the ice of the shallower coasts ( that will freeze very late) will probable freeze, but maybe exceptionally late to be very thin at the start of the melt season, as you say in previous posts
Sorry, excuse my bad english

BornFromTheVoid

  • Nilas ice
  • Posts: 1250
    • View Profile
  • Liked: 579
  • Likes Given: 199
Re: The 2020/2021 freezing season
« Reply #296 on: October 14, 2020, 10:57:40 AM »
Animation, 8th to 13th.
I recently joined the twitter thing, where I post more analysis, pics and animations: @Icy_Samuel

Freegrass

  • Nilas ice
  • Posts: 1640
  • None but ourselves can free our minds...
    • View Profile
  • Liked: 522
  • Likes Given: 765
Re: The 2020/2021 freezing season
« Reply #297 on: October 14, 2020, 01:17:35 PM »
Latest Five Day Forecast
Wind @ Surface + Total Precipitable Water
Wind + Temp @ 850hPa
Large GiFS!
Now let's pray...

If the science don't fit our beliefs, we pray to God and cuddle up in our own delusional fantasy where everything makes sense again...

grixm

  • Frazil ice
  • Posts: 349
    • View Profile
  • Liked: 209
  • Likes Given: 68
Re: The 2020/2021 freezing season
« Reply #298 on: October 14, 2020, 01:34:47 PM »
Definitely some more refreeze outside the Lena delta.

uniquorn

  • Young ice
  • Posts: 2831
    • View Profile
  • Liked: 1290
  • Likes Given: 258
Re: The 2020/2021 freezing season
« Reply #299 on: October 14, 2020, 03:29:34 PM »
Definitely some more refreeze outside the Lena delta.
Yes. Today may be the last day to check using corrected reflectance. Sea temperatures 50km from the coast were still just a touch cooler than the Lena river. Low cloud and fog a bit cooler.
Rainbow1 palette on viirs brightness temperature.
https://go.nasa.gov/374tZkp