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Neven

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Arctic temperature layers and inversions
« on: February 18, 2017, 10:43:25 PM »
Over on the 2016/2017 freezing season thread, commenter Aslan is providing lots of information that shouldn't get lost in the mire of comments. And so I open this thread to make it easier to find.

Below is Aslan's post:

---------

Using the reanalysis, we can calculate also the mean of the downward radiation flux. Of course, it is the reanalysis, with a coarse resolution and its own limitations (especially discontinuities due to inclusion of varying kinds of data), but I think it is quite good nonetheless, if we look at the values after 1981 (start of the satellite era). So, the downward radiation flux, or the infrared emitted by the atmosphere toward Earth surface (one funny thing when you have some knowledge in physics, you know you are a being of light and that you are shining :D ). Data are for the whole above 69°N (radiation data are along a Gauss grid, I take values up to 69.5217°N, cell index 11), averaged according to surface (hoping I make no mistakes), for each day from 1st January, 1981 :



It is looking quite like the graph of the temperature according to the DNMI, which is not unexpected by the way. We are tempted to say, a warmer atmosphere radiates more energy, so what is the point?

Actually there is more in this. The mean level of radiation for Earth is around 5 - 6 km, so around 500 hPa, take or given a couple of hPa. Relationship between temperature and radiation is not linear, so we can calculate the flux of a black-body with our old friend, the equation of a black-body :

Flux = 5.67e-8 * T^4

The grid for the temperatures are not the same as the one for the radiation data, but I didn't care about this. The precision of the reanalysis is probably far worse than the small difference induced by averaging over a slightly different area. So I used the region above 67.5°N for the temperatures, calculate the radiation flux from the temperature and compare with DWLR, and averaged for the three months from November to January (February is still ongoing un 2017). The year of reference is that of January (ie., NDJ 2017 is the average of ND 2016 and J 2017) :



Values are roughly the same, so yeah 500 hPa is a good level. But correlation is not looking good actually... I look to other levels, but the correlation is not significantly better. As a side-note, the temperatures at 500 hPa :



So, what if we try with the precipitable water?



It looks way better...

So I detrend the series, to compare the cross-correlation. Anomalies of the downward radiation flux, explained by the anomalies of the black-body emmision :



Anomalies of the downward radiation flux, explained by the anomalies of the precipitable water :



Anomalies of the anomalies of the precipitable water, explained by the temperature at 500 hPa :



I will not try an argument about chickens and eggs. It is of course difficult to disentangled all the mechanisms ongoing. But at least the increasing of water vapor, linked to warming of the temperatures but also to the decrease of Arctic sea ice, is increasing downward radiations.

The major point is that a warming of 20°C or 30°C is not impossible at surface is thus not impossible. With global warming, the "thin" -a 2 km thick and 20°C inversion is massive for an inversion in the absolute, but compared to the whole atmosphere this it is not so thick nor so cold- the "thin" layer of permanent inversion is set to be destroyed, with only marginal warming above. Usually there is around 5 to 10°C between surface and 850 hPa. Even a 7-8°C lapse rate with a 850 hPa layer around 250K would imply a mean surface temperature a bit below 260K, around -15°C, barely enough cold for sea ice. This graph shows the warming of the Arctic layers :



The surface 1000 hPa is warming fast and is now warmer than the 850 hPa for the first time since 1981 (and probably since many millenniums...). And the strength of the inversion (or of the now non-inversion) taken as the difference between the 850 hPa and 1000 hPa temperatures :





I will post the spreadsheet with the data a bit latter ;)

P.S. : THe spreadsheet www.climatvisu.fr/Neven_ASIF/dlwr_out_2.ods
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aslan

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Re: Arctic temperature layers and inversions
« Reply #1 on: February 18, 2017, 10:48:13 PM »
So we move and I was going topost to the freezing thread :D


Killer graph. That yellow line is showing almost 20 degC of warming!


I will speak about myself sorry ^^" But if is "fun", I never, when I wrote the post, I never realize the magnitude of the warming. I said 20°C, 30°C, but in my brain no connections happened, I was not aware of what I was writing (the global warming, the weed of the future...). It is when I read you, just minuts ago, that I understand I was speaking about full 20°C in 35 years. And it was like "Salva nos Domine" et "Eleison imas" in my head. And I was not able to believe I made no error so I double check, and I even plot the map from the reanalysis. For example this is the exact area (all things above 67.5°N) for the year 1983, a bit cool but not so much (the first low point to the left, after the small uptick of 1982):





And this is for 2017 :





If the reanalysis is not widely in error (really unlikely), yeah there is probably something around 15 - 20°C of warming.

Without trying to put me on the front scene, but I am worry by this change since 2012, when Kara sea remained open in the winter. I discovered Ostrov Vize this winter, and since then Ostrov Vize is one thing that keep me awake in the night. This year, it was localized, but some strong hints about a feedback from the cloud, the water vapor, and the open Ocean, were clearly visible.
I agree with jdallen, models are probably not able to fully simulate the feedbacks which are now at play, and we are probably in for a state change without gloves nor care. There is some papers about the clouds, the water vapor feedback, the permanent inversion in Arctic, but I am not aware of any paper which is really relevant for the last two winters and which anticipate such a fast state change.

http://www.nature.com/ngeo/journal/v4/n11/full/ngeo1285.html

http://geosci.uchicago.edu/~abbot/Code/Abbot-Tziperman-2008/abbot-tziperman-08b.pdf

https://www.atmos.washington.edu/~bitz/holland_etal2006GRL.pdf et http://www.geo.brown.edu/research/Fox-Kemper/classes/CU/ATOC6020_08/notes/08_05_Holland.pdf

http://www.atmos-chem-phys.net/16/14343/2016/acp-16-14343-2016.pdf

http://www.cesm.ucar.edu/events/wg-meetings/2010/presentations/amwg/kay.pdf

Etc... But to my knowledge nothing really pertinent for the current and ongoing crash. As jdallen said


It may be there are relevant papers we haven't seen, and yes, this implies a pretty scary feedback and an implied tipping point.  If ice drops much below 3M KM2, the additional heat uptake and H2O being injected into the atmosphere combined with that being imported from steady less dramatic changes further south may translate to a rapid state change in atmospheric circulation that no one has envisioned.

The short ride to to that new state will likely be very bumpy.


models are probably somewhat lost and we have to put more attention to what is happening in the Arctic now.

Merci beaucoup.


De rien ^^

Tor Bejnar

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Re: Arctic temperature layers and inversions
« Reply #2 on: February 18, 2017, 11:43:42 PM »
I don't understand much of this analysis, but the correlation with water vapor makes a certain amount of intuitive sense because "Water vapor is the most powerful greenhouse gas."
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Pragma

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Re: Arctic temperature layers and inversions
« Reply #3 on: February 18, 2017, 11:49:31 PM »
Wow! That's a lot for a newbie to absorb. Thank you for all that work. Just when I was trying to undertand what was going on in the arctic, I realize that I was only thinking in two dimensions, or perhaps three, but only in terms of the ocean halocline and thermocline

This appears to be somewhat related to the work done by Prof James G. Anderson and his group.

https://www.arp.harvard.edu/our-research

I also recall some hypotheses regarding the Hadley, Ferrell and Polar cells collapsing into one cell per hemisphere. I can't remember now (poor note keeping :-) ) but it might have been Jennifer Francis. The idea implied a drastically reduced temperature differential temperature between the equator and the poles.

Has anyone come across this and is there some reason why it must be one cell or three, not two?

As others have mentioned, these changes appear to be historic, but I have to remind myself that this is just one season so the implications are yet to be revealed.

That said, I can't help but wondering if what we are seeing is a "bumpy ride" to a new climate state, or if the bumpy ride is the new climate state. To answer that we first need to get past the implications of an ice free arctic summer, and then see at what point the remaining ice stabilizes after the ocean warms.

Of course, that assumes that the arctic ice does actually stabilize. I saw a recent talk by Jennifer Francis where she said "there will always be ice in the arctic". I was immediately struck by the thought that that may not be true in any meaningful sense.  :(   

jdallen

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Re: Arctic temperature layers and inversions
« Reply #4 on: February 19, 2017, 12:01:36 AM »
I don't understand much of this analysis, but the correlation with water vapor makes a certain amount of intuitive sense because "Water vapor is the most powerful greenhouse gas."
You are not alone, Tor.  I'm needing to put a lot of effort into wrapping my head around the dynamics of it.
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Re: Arctic temperature layers and inversions
« Reply #5 on: February 19, 2017, 12:16:21 AM »
I understand enough to know this is a monumental change. When speaking of a warmer layer for the lowest 2 km approx., many of us would say less cool rather than warmer, but still, it hurts. I don't know if it would only lower the number of FDD's or also make the ones counted less effective, but either way thickening is hindered. And the smaller gradient slows the process for heat to escape open water. Probably not the deepest interpretation.

josh-j

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Re: Arctic temperature layers and inversions
« Reply #6 on: February 19, 2017, 12:26:33 AM »
Well we are already experiencing the first consequences of the ground-level warming surely. The next question is how a lack of inversion would affect atmospheric dynamics. Note one of Aslan's earlier links (http://www.nature.com/ngeo/journal/v4/n11/full/ngeo1285.html) which suggests the temperature inversion had an amplifying effect on warming - could that amplification be lost?

Even if so, I suppose it is replaced by warming from the increased atmospheric moisture content. But these are just idle musings (I have no knowledge but am trying to learn).

I am particularly interested in whether the loss of inversion itself (rather than just the temperature rise) would have effects on weather patterns locally and more widely in the winter..?

Thanks for this Aslan.

Sebastian Jones

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Re: Arctic temperature layers and inversions
« Reply #7 on: February 19, 2017, 12:32:55 AM »
If I understand this analysis (not a given....), it helps explain how the arctic was temperate all year round during warm periods. Watching the decline of sea ice one knows that the planet is approaching a warm arctic phase, but the mechanism was never clear. I thick it is looming out of the fog now. Brilliant work!

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Re: Arctic temperature layers and inversions
« Reply #8 on: February 19, 2017, 12:55:23 AM »
I understand enough to know this is a monumental change. When speaking of a warmer layer for the lowest 2 km approx., many of us would say less cool rather than warmer, but still, it hurts. I don't know if it would only lower the number of FDD's or also make the ones counted less effective, but either way thickening is hindered. And the smaller gradient slows the process for heat to escape open water. Probably not the deepest interpretation.
FDDs will get lower but, sea ice cannot start forming if temp does not drop below -10/-11C
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DrTskoul

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Re: Arctic temperature layers and inversions
« Reply #9 on: February 19, 2017, 12:58:03 AM »
Well we are already experiencing the first consequences of the ground-level warming surely. The next question is how a lack of inversion would affect atmospheric dynamics. Note one of Aslan's earlier links (http://www.nature.com/ngeo/journal/v4/n11/full/ngeo1285.html) which suggests the temperature inversion had an amplifying effect on warming - could that amplification be lost?

Even if so, I suppose it is replaced by warming from the increased atmospheric moisture content. But these are just idle musings (I have no knowledge but am trying to learn).

I am particularly interested in whether the loss of inversion itself (rather than just the temperature rise) would have effects on weather patterns locally and more widely in the winter..?

Thanks for this Aslan.


Inversion and density stratification reduces mixing heights and restricts interaction between stratified layers. Destruction of temp inversion leads to a more dynamic atmosphere..
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Ice Shieldz

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Re: Arctic temperature layers and inversions
« Reply #10 on: February 19, 2017, 01:11:22 AM »
Destruction of temp inversion leads to a more dynamic atmosphere..
Could we already be seeing the effects of this in the intensity of the storms we've been seeing in the arctic this fall/winter?

georged

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Re: Arctic temperature layers and inversions
« Reply #11 on: February 19, 2017, 01:42:14 AM »
So we move and I was going topost to the freezing thread :D


Killer graph. That yellow line is showing almost 20 degC of warming!

I will speak about myself sorry ^^" But if is "fun", I never, when I wrote the post, I never realize the magnitude of the warming. I said 20°C, 30°C, but in my brain no connections happened, I was not aware of what I was writing (the global warming, the weed of the future...). It is when I read you, just minuts ago, that I understand I was speaking about full 20°C in 35 years. And it was like "Salva nos Domine" et "Eleison imas" in my head. And I was not able to believe I made no error so I double check, and I even plot the map from the reanalysis. For example this is the exact area (all things above 67.5°N) for the year 1983, a bit cool but not so much (the first low point to the left, after the small uptick of 1982):

De rien ^^

This work is very good. You should look at publication, it deserves another audience!

Pmt111500

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Re: Arctic temperature layers and inversions
« Reply #12 on: February 19, 2017, 04:25:08 AM »
Good call, Neven! Good work, Aslan!

I'd probably check the winter methane numbers for Arctic if there are some available. The rise in those might play (probably a minor) role in all of this. Terrible thing to observe the change of area larger than Canada first hand. This connects to so many issues i stop here. Thanks, though this is terrible.

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« Last Edit: February 19, 2017, 04:41:12 AM by Pmt111500 »
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Re: Arctic temperature layers and inversions
« Reply #13 on: February 19, 2017, 06:09:18 PM »
Aslan, C'est magnifique. Regardless of the complexities and feedbacks which doubtless make the timing and post-change regime uncertain, it is the the most concise and convincing exposition of why there will be a tipping point, and of what it will mean, that I have seen.

So much so that I hesitate to introduce distraction from the message that it sends with speculation as to what will be the most significant feedback mechanisms, and what will be their net effect. I'm guessing, for example, that both upward and downward radiation will be interdependent with what the cloud coverage, vertical distribution and density end up looking like in the new regime?

Jim Williams

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Re: Arctic temperature layers and inversions
« Reply #14 on: February 19, 2017, 06:19:39 PM »
What is the transmission and reflection spectra for clouds of various types?  I'm certain that low waterlogged clouds reflect less Sunlight and trap more heat, but I have little understanding of by how much.  Basically...when does the ocean climate completely overwhelm the desert?

be cause

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Re: Arctic temperature layers and inversions
« Reply #15 on: February 19, 2017, 06:38:07 PM »
What is the transmission and reflection spectra for clouds of various types?  I'm certain that low waterlogged clouds reflect less Sunlight and trap more heat, but I have little understanding of by how much.  Basically...when does the ocean climate completely overwhelm the desert?

 around about now ?
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Jim Williams

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Re: Arctic temperature layers and inversions
« Reply #16 on: February 19, 2017, 06:50:52 PM »
What is the transmission and reflection spectra for clouds of various types?  I'm certain that low waterlogged clouds reflect less Sunlight and trap more heat, but I have little understanding of by how much.  Basically...when does the ocean climate completely overwhelm the desert?

 around about now ?

There...be cause's answer is now meaningful.

Csnavywx

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Re: Arctic temperature layers and inversions
« Reply #17 on: February 19, 2017, 09:33:13 PM »
If the surface temp is above the 850 and 500mb temp, there's no longer a net inversion. An inversion, by definition, is a negative lapse rate or an increase in temperature with height. So, the mean state has switched from an inversion to essentially isothermal. With additional heating, the lower layers will exhibit a positive lapse rate. It's important from the perspective of cloud generation as it's easier to generate clouds and increase precipitation rates the less stable the atmosphere is with respect to buoyancy.

Low water clouds reflect more sunlight but trap infrared heat even better than high ice clouds. If you want confirmation of this, take a look at a visible satellite with low clouds overlain by jet cirrus. The cutoff for ice/water clouds is about -10C. Ice crystals tend to increasingly dominate past -10C and are virtually all ice below -20C except in certain circumstances -- like convective clouds. The phase transition between 253K and 263K is really important with respect to cloud water content. Of course, since the sun doesn't shine during the winter, having more water droplet-dominated clouds will increase DLWR -- acting as a net positive feedback.

aslan

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Re: Arctic temperature layers and inversions
« Reply #18 on: February 20, 2017, 11:20:46 AM »
This appears to be somewhat related to the work done by Prof James G. Anderson and his group.

https://www.arp.harvard.edu/our-research

I also recall some hypotheses regarding the Hadley, Ferrell and Polar cells collapsing into one cell per hemisphere. I can't remember now (poor note keeping :-) ) but it might have been Jennifer Francis. The idea implied a drastically reduced temperature differential temperature between the equator and the poles.

Has anyone come across this and is there some reason why it must be one cell or three, not two?


It is not possible to have one cell, due to conservation of angular momentin. Coriolis deflects flow to the right in NH, to the left in SH -or to the west in each case-. If their is aire flow away from equator and toward Poles, at some point, air accelerates too much, and can't keep going northward. It exists some theories about a one cell circulation during equables climates, but the argument is very weak to say the least.

https://www.seas.harvard.edu/climate/eli/research/equable/hadley.html

http://www.to.isac.cnr.it/aosta_old/aosta2014/LecturesSeminars/Tziperman_2.pdf

Of course, that assumes that the arctic ice does actually stabilize. I saw a recent talk by Jennifer Francis where she said "there will always be ice in the arctic". I was immediately struck by the thought that that may not be true in any meaningful sense.  :(


Yeah, probably too optimistic, but reality is hard.

If the surface temp is above the 850 and 500mb temp, there's no longer a net inversion. An inversion, by definition, is a negative lapse rate or an increase in temperature with height. So, the mean state has switched from an inversion to essentially isothermal. With additional heating, the lower layers will exhibit a positive lapse rate. It's important from the perspective of cloud generation as it's easier to generate clouds and increase precipitation rates the less stable the atmosphere is with respect to buoyancy.

Low water clouds reflect more sunlight but trap infrared heat even better than high ice clouds. If you want confirmation of this, take a look at a visible satellite with low clouds overlain by jet cirrus. The cutoff for ice/water clouds is about -10C. Ice crystals tend to increasingly dominate past -10C and are virtually all ice below -20C except in certain circumstances -- like convective clouds. The phase transition between 253K and 263K is really important with respect to cloud water content. Of course, since the sun doesn't shine during the winter, having more water droplet-dominated clouds will increase DLWR -- acting as a net positive feedback.


Yes.



A view of the current difference of temperatures between 850 and 1000 hPa for last 3 months:


Csnavywx

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Re: Arctic temperature layers and inversions
« Reply #19 on: February 20, 2017, 11:39:45 PM »
It would be interesting to calculate the increase in DLWR as the average temperature crosses the step change on that graph. Might be a tipping point of sorts in there.

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Re: Arctic temperature layers and inversions
« Reply #20 on: February 22, 2017, 05:18:47 PM »
speaking about full 20°C in 35 years


Perhaps you could say what that yellow line is. Is it pressure level of 1000 ie near ground level? What area and time of year?

Compared with for example
http://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=1838.0;attach=42108;image
showing 2.5 degrees warming over 55 years for 70-90N

or DMI 80N showing less than 10 degrees of warming in winter and slightly negative in summer.

I am slightly confused how this 20C in 35 years arises / fits in with other measures we have.

Tigertown

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Re: Arctic temperature layers and inversions
« Reply #21 on: February 22, 2017, 05:36:52 PM »
speaking about full 20°C in 35 years


Perhaps you could say what that yellow line is. Is it pressure level of 1000 ie near ground level? What area and time of year?

Compared with for example
http://forum.arctic-sea-ice.net/index.php?action=dlattach;topic=1838.0;attach=42108;image
showing 2.5 degrees warming over 55 years for 70-90N

or DMI 80N showing less than 10 degrees of warming in winter and slightly negative in summer.

I am slightly confused how this 20C in 35 years arises / fits in with other measures we have.


I think aslan was saying there was a 20oC  shift in the differential of 1000 hpa and 850 hpa  temps. for the parameters given. Not that the surface itself had warmed that much.

wehappyfew

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Re: Arctic temperature layers and inversions
« Reply #22 on: February 22, 2017, 06:14:05 PM »
The answer is in aslan's spreadsheet attached to the OP.

aslan downloaded the 1000 mb temperatures (in degrees C), shown in the second tab, rows 177 to 213.

He then calculated a blackbody emissivity for each month's temperature with the formula...
=(B213+273.15)^4*0.0000000567
... in columns O to Z

He took the average for the 3 months Nov, Dec, and Jan in column AB

Finally, he copied that average over to tab3 in cells D3 to D38, but called it "Temperature in Kelvins" when it is clearly not a temperature at all, but is an emissivity (possibly in units of Watts).

The difference in emissivity from the 80's to today is about 20 Watts, not 20 Kelvins.

The temperature increase from the 80's to today is actually about 5 Kelvins.

His main point that the temperature inversion has disappeared still stands. The temperature difference between 850 mb and 1000 mb has changed from about -2K to +1K (the near-surface is now warmer than 850 mb).

crandles

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Re: Arctic temperature layers and inversions
« Reply #23 on: February 23, 2017, 12:45:52 AM »
The difference in emissivity from the 80's to today is about 20 Watts, not 20 Kelvins.

The temperature increase from the 80's to today is actually about 5 Kelvins.

His main point that the temperature inversion has disappeared still stands. The temperature difference between 850 mb and 1000 mb has changed from about -2K to +1K (the near-surface is now warmer than 850 mb).

Thank you.

crandles

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Re: Arctic temperature layers and inversions
« Reply #24 on: February 23, 2017, 02:25:45 PM »
There seem a few effects of loss of temperature inversion:

Convection starts more readily. Til now heating the ocean has just warmed the near surface temperatures. Now that heat will convect upwards where it can be lost to space more easily. Therefore the rate of warming of near surface air might slow down.

However there are other effects, rising air that cools is going to form clouds and in Arctic night probably at quite a low level. That probably slows the rate of loss of heat.

Then again rising cooling clouds with mean the moisture precipitates out which becomes a means of moving heat upwards by latent heat effects and from higher levels the heat can more easily be lost to space.

There is probably more effects and I have no idea which effects are strongest or what the overall effect will be.

.

Is it possible to calculate the percentage of time each month has a temperature inversion and graph how each month's percent of inversion time varies over the last 20 years for 75/80-90N?

Tigertown

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Re: Arctic temperature layers and inversions
« Reply #25 on: February 23, 2017, 02:47:00 PM »
@crandles
I am still working toward understanding this better myself. I believe what is being said is that as the lower level heats and reverses the initial inversion, then a positive feedback is started and the heat is radiated downward after that point, instead of cooling into space.
You can read the abstract on the following.

www.nature.com/ngeo/journal/v4/n11/full/ngeo1285.html

P.S. I wish that I could pay for this article for the whole forum to use, but I imagine it doesn't work that way. It just wouldn't make sense to pay it for my use only.

crandles

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Re: Arctic temperature layers and inversions
« Reply #26 on: February 23, 2017, 04:02:29 PM »

www.nature.com/ngeo/journal/v4/n11/full/ngeo1285.html

P.S. I wish that I could pay for this article for the whole forum to use, but I imagine it doesn't work that way. It just wouldn't make sense to pay it for my use only.


Just look around. Finding Authors web page often helps:

https://www.researchgate.net/publication/232796146_Arctic_winter_warming_amplified_by_the_thermal_inversion_and_consequent_low_infrared_cooling_to_space

Tigertown

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Re: Arctic temperature layers and inversions
« Reply #27 on: February 23, 2017, 05:22:52 PM »
Thanks crandles. I will bookmark this now. I wish I had some nzt.

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Re: Arctic temperature layers and inversions
« Reply #28 on: February 23, 2017, 07:11:35 PM »
@crandles
I am still working toward understanding this better myself. I believe what is being said is that as the lower level heats and reverses the initial inversion, then a positive feedback is started and the heat is radiated downward after that point, instead of cooling into space.

My reading of the paper is that the inversion is a positive factor in surface warming amplification. Therefore to my mind, once the inversion is lost the amplification could reduce.

As the paper says:

"The ability of the Arctic wintertime clear-sky atmosphere to cool to space decreases with inversion strength."

Of course there are many more than this single factor in Arctic warming amplification and clearly the ongoing (?) weakening of the inversion is not saving the Arctic so far. But my non-expert reading is that at least for this one specific feedback, increased warming might actually reduce the feedback as the inversion strength weakens.

I'd be curious to know the thoughts of you intelligent people on this.  :)

Tigertown

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Re: Arctic temperature layers and inversions
« Reply #29 on: February 23, 2017, 07:42:20 PM »
The lowest two km of atmosphere, which in the initial inversion were cooler than the layer above. Now that the inversion is breaking down, the lower two km of atmosphere are holding the heat in and not letting it escape. The heat radiated from this lower layer tends to radiate down, hence the feedback.

You don't have to understand every detail of the subject or be a genius to understand that this is bad for the Arctic and sea ice formation. The original state was considered the inversion state, and it protected the ice. Losing this harms it.

Note: Inversion can work two ways. By the layer above being warmer than the one below, as it usually was in the past. Also, the layer above being cooler than the one below. Most references to inversion are to the original state, where the layer below is the coolest, but what the writer here is saying is that as the departure(strength) in temperatures between the warmer lowest layer and the cooler layer above becomes greater, there is less cooling to space. What radiates out is mostly from the cooler upper layer. The warmer lower layer radiates mostly downward.

   This all can be confusing because I think of inversion as the cooler layer being the closest to the surface. Maybe the situation where the warmer layer becomes the one closer to the surface should be referred to as non-inversion or reverse-inversion for the Arctic. It would be the normal state elsewhere. Anyway, the choice of wording is confusing on this subject.
« Last Edit: February 23, 2017, 08:14:42 PM by Tigertown »

crandles

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Re: Arctic temperature layers and inversions
« Reply #30 on: February 23, 2017, 11:58:43 PM »
The lowest two km of atmosphere, which in the initial inversion were cooler than the layer above. Now that the inversion is breaking down, the lower two km of atmosphere are holding the heat in and not letting it escape. The heat radiated from this lower layer tends to radiate down, hence the feedback.

I read it the same way as Josh-j.

When there is an inversion,
Instead, the additional radiation that is generated by the warming of these layers is directed downwards, and thus amplifies the warming

when the inversion is gone then that amplifying mechanism is gone.

More explicitly in the paper
The extra outgoing radiation originates almost entirely from the atmosphere when mixing is
artificially increased. This implies that a weaker inversion, with stronger temperature increases higher up, enables the atmosphere to lose the additional energy more effectively. Hence, the presence of the Arctic inversion makes the (negative) infrared feedback less negative (using the feedback framework used in for instance ref. 5), which thus acts to amplify Arctic warming
« Last Edit: February 24, 2017, 12:10:35 AM by crandles »

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Re: Arctic temperature layers and inversions
« Reply #31 on: February 24, 2017, 01:06:51 AM »
Again, you need to be specific about which scenario that you are considering to be the inversion, and which to be where it has gone. No one situation exists throughout the whole Arctic. This chart shows that for a large area the 1000 hpa is warmer than the 850 hpa. In those areas the heat radiates downward, instead of escaping to space as it would formerly have been expected. I understand this to show the averages from the last three months.

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Re: Arctic temperature layers and inversions
« Reply #32 on: February 24, 2017, 01:11:08 AM »
surely it the replacement of clear skies with cloud that is making the main difference ?
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Re: Arctic temperature layers and inversions
« Reply #33 on: February 24, 2017, 01:36:45 AM »
surely it the replacement of clear skies with cloud that is making the main difference ?

This makes a lot of sense if data supports it...So what are the ramifications?

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Re: Arctic temperature layers and inversions
« Reply #34 on: February 24, 2017, 01:24:58 PM »
One more question. Devils advocate here.

Is there ANY scenario wherein the reversal of temperature inversion over the past 20-30 years (and especially the past few) is false because the regional temperature data is erroneous/false?

I'm not a denier, I see the changes outside, so I know the above question is silly.. but I mean... that kind of seems to be our only out at this point. If it's just not real in the first place.. otherwise, the more I think about how monumental of a change this is, the more I have low optimism for the immediate future.

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Re: Arctic temperature layers and inversions
« Reply #35 on: March 10, 2017, 06:55:30 PM »
Anyone think that the Atmospheres circulations are looking strange? :o

 I'm interested that at all levels from 1km right up to thirty km the circulations seem to be stacking quite neatly above each other. ???

Has the troposphere/ stratosphere boundary lifted? The decrease in temp with altitude seems to be now continuing to between 18 km and 30 km darn near everywhere. Is there even a distinction between them anymore?  :-\

The ferocious planetwide mixing that seems to be establishing, particularly from 700 hPa 3km, right up to 10hPa, 32km has regions at both the poles only 25c below equatorial temps at the 3km altitude, and very close planetwide above that. A little warmer above the poles than the equator at 18km in fact.

I've been watching this closely over the past few days. Not an expert in this. Is it far from normal? Seems major changes are occurring almost daily.

temp s pole -45.8,  n pole -51.6, Eq -45.9  at 32km: 10 hPa
https://earth.nullschool.net/#current/wind/isobaric/10hPa/overlay=temp/atlantis=116.25,13.27,130/loc=55.261,-82.453

temp s pole -47.3,  n pole -64.6, Eq -78.9  at 18.5km: 70 hPa
https://earth.nullschool.net/#current/wind/isobaric/70hPa/overlay=temp/atlantis=116.25,13.27,130/loc=55.261,-82.453

temp s pole -48,  n pole -57.9, Eq -41.4  at 10km: 250 hPa
https://earth.nullschool.net/#current/wind/isobaric/250hPa/overlay=temp/atlantis=116.25,13.27,130/loc=100.325,-87.117

temp s pole -40.4,  n pole -37.6, Eq -5.3  at 5.5km: 500 hPa
https://earth.nullschool.net/#current/wind/isobaric/500hPa/overlay=temp/atlantis=116.25,13.27,130/loc=100.325,-87.117

temp s pole -41.3,  n pole -25.4, Eq  10.4  at 3km: 700 hPa
https://earth.nullschool.net/#current/wind/isobaric/700hPa/overlay=temp/atlantis=116.25,13.27,130/loc=100.325,-87.117

temp s pole -32.6,  n pole -20.6, Eq 17.8  at 1.5km: 850 hPa
https://earth.nullschool.net/#current/wind/isobaric/850hPa/overlay=temp/atlantis=116.25,13.27,130/loc=100.325,-87.117

temp s pole -25, n pole -31.1, Eq 27.2  at 100m: 1000 hPa
https://earth.nullschool.net/#current/wind/isobaric/1000hPa/overlay=temp/atlantis=116.25,13.27,130/loc=99.954,0.248

How do I lift screenshots from nullschool in chrome? anyone?
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Re: Arctic temperature layers and inversions
« Reply #36 on: March 11, 2017, 09:03:15 PM »
Had to add an extension to chrome for the screenshots
1000hpa 100m

850hpa 1.5km

700hpa 3km

500hpa 5.5km



« Last Edit: March 11, 2017, 09:09:44 PM by Hyperion »
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Re: Arctic temperature layers and inversions
« Reply #37 on: March 11, 2017, 09:11:35 PM »
250hpa 10km

70hpa 18.5km

10hpa 30km

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