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Author Topic: Comet Ison, methane, noctilucents and Strat temps?  (Read 3799 times)

Gray-Wolf

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Comet Ison, methane, noctilucents and Strat temps?
« on: June 25, 2013, 12:59:56 PM »
Whilst looking forward to the show this Nov/december I became aware of the Jan 12th event ( and week following) where we pass through the dust stream left by the Comet as it passes.

We are told that this 'debris' is too small to give us a traditional meteor shower but that the 'dust' will act as condensation nucliei in the upper strat leading to possible noctilucent displays for many months ( right into the normal 'season' for them?)

I then began to mull what impacts this 'dust' may bring with it to the global environment. I know the debate on trop clouds appears to be leaning toward them re-inforcing warming by trapping more heat but would the same apply to an unusual concentration of noctilucent clouds?

Current research also puts 'methane' in the frame for introducing water vapour into the upper strat ( oxidation of the CH4 leadingto H2O) and so we might be currently 'seeding' the strat with our increases in methane?

 I have no idea of how long it takes for a methane molecule to rise from ground level to the upper atmosphere  and so do not know whether a 'summer season' of methane production is presented in the Stratosphere over the following winter?

Current temps over Alaksa and Siberia would suggest that we will show a 'peak' in methane production over the permafrost/wetlands there? Could this be preparing the Strat for Isons cargo of dust on Jan 12th?
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Rod

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Re: Comet Ison, methane, noctilucents and Strat temps?
« Reply #1 on: June 16, 2019, 01:18:08 AM »
Something interesting has been happening during the last few weeks.  Noctilucent clouds are being seen worldwide at latitudes far below where they have ever been seen before.

Noctilucent clouds are very high in our atmosphere, approximately 50 miles up.  They glow at night because they are high enough to be illuminated by the sun. 

There are no reports of Noctilucent clouds ever being observed prior to the industrial revolution.  In order to form, they need dust in the atmosphere and water vapor that forms ice crystals very high up.  As Gray-Wolf points out above (in a six year old post) methane has been identified as helping to induce water vapor ice crystals in the highest parts of our atmosphere. 

Noctilucent clouds might be a marker for increased atmospheric methane levels.  “Our planet’s idiot light.”  More methane means it is more likely to see them.  Methane levels are currently at record levels.   

Mark Boslough is a scientist that recently started a thread on Twitter discussing how unusual it is that this summer we are seeing Noctilucent clouds at such low latitudes. 

Below are screen shots of four of his posts.  If you find this topic interesting, I encourage you to search his name on Twitter and read the entire thread.  I found it fascinating. 


vox_mundi

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Re: Comet Ison, methane, noctilucents and Strat temps?
« Reply #2 on: June 16, 2019, 01:42:38 AM »
Very interesting. Thanks Rod.  :)
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be cause

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Re: Comet Ison, methane, noctilucents and Strat temps?
« Reply #3 on: June 16, 2019, 01:43:15 AM »
I've been seeing them for years here in N. Ireland .. until this non-summer ..

Last year I spent a night vigil on the N. Coast of Donegal awaiting mid-summer sunrise in alignment with the Great glen fault in Scotland .  I was kept company by a beautiful display of noctilucent clouds through the hours of 'simmer dim' .
 The sun rose perfectly aligned with the glen ,immediately passing over the 3 perfectly pyramidal Paps of Jura .. and I had my explanation for an alignment of neolithic sites in Ireland .. :) .. b.c.
 
« Last Edit: June 16, 2019, 08:46:22 AM by be cause »
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 + 2 = 2021 + 1 .. you gotta laugh .. :)

Rod

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Re: Comet Ison, methane, noctilucents and Strat temps?
« Reply #4 on: June 16, 2019, 02:20:01 AM »
I've been seeing them for years here in N. Ireland .. until this non-summer.
 

That is an interesting observation that you are not seeing them in N. Ireland where they are expected to be seen, but they are showing up as far south as New Mexico and Southern California.  🤔

be cause

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Re: Comet Ison, methane, noctilucents and Strat temps?
« Reply #5 on: June 16, 2019, 02:47:10 AM »
sorry Rod .. more to do with the weather .. too many regular clouds .. and it's cold out .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 + 2 = 2021 + 1 .. you gotta laugh .. :)

Rod

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Re: Comet Ison, methane, noctilucents and Strat temps?
« Reply #6 on: June 16, 2019, 03:04:00 AM »
sorry Rod .. more to do with the weather .. too many regular clouds .. and it's cold out .. b.c.

Damn weather!  Send some of that cold to Siberia and save us from this terrible melting season 😂

b_lumenkraft

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Re: Comet Ison, methane, noctilucents and Strat temps?
« Reply #7 on: June 16, 2019, 05:46:24 AM »

vox_mundi

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Re: Comet Ison, methane, noctilucents and Strat temps?
« Reply #8 on: May 29, 2020, 02:35:52 PM »
NASA's AIM Satellite Spots First Arctic Noctilucent Clouds of the Season


These animated images show AIM’s observations from the first week of the Arctic noctilucent cloud season, which began on May 17, 2020. The colors — from dark blue to light blue and bright white — indicate the clouds’ albedo, which refers to the amount of light that a surface reflects compared to the total sunlight that falls upon it. Things that have a high albedo are bright and reflect a lot of light. Things that don’t reflect much light have a low albedo; they are dark.

NASA's Aeronomy of Ice in the Mesosphere spacecraft—AIM for short—first spotted wisps of these noctilucent, or night-shining, clouds over the Arctic on May 17. In the week that followed, the ghost-like wisps grew into a blur, quickly filling more of the Arctic sky. This is the second-earliest start of the northern season yet observed, and the season is expected to run through mid-August.

The seasonal clouds hover high above the ground, about 50 miles overhead in a layer of the atmosphere called the mesosphere. ... The icy clouds, reflecting sunlight, shine bright blue and white. They first appear in summer—around mid-May in the Northern Hemisphere and mid-November in the Southern—when the mesosphere is most humid, with the season's heat lofting moisture up to the sky.

Also known as polar mesospheric clouds (because they tend to huddle around Earth's poles), these clouds help scientists better understand the mesosphere and how it's connected to the rest of the atmosphere, weather and climate.

See also: https://forum.arctic-sea-ice.net/index.php/topic,416.msg205648.html#msg205648

for last year's view
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be cause

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Re: Comet Ison, methane, noctilucents and Strat temps?
« Reply #9 on: June 21, 2021, 04:45:51 AM »
beautiful noctilucent clouds to N. here in Inishowen , Ireland . I've been up all night enjoying the sights , now @ 1 hour 'till sunrise . Hope to post photos some day .. b.c.
2007 + 5 = 2012 + 4 = 2016 + 3 = 2019 + 2 = 2021 + 1 .. you gotta laugh .. :)

gerontocrat

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Re: Comet Ison, methane, noctilucents and Strat temps?
« Reply #10 on: June 22, 2021, 11:42:34 AM »
Here in N.W. England, my daughter took the attached photo on her mobile phone yesterday (21 June) at 11.30 p.m, GMT looking West.

It was exactly 2 years ago she took similar photos which I posted on the Arctic Cafe on 22 June 2019. https://forum.arctic-sea-ice.net/index.php/topic,179.msg207647.html#msg207647

I think I read somewhere that these clouds are happening more frequently and as usual AGW is the culprit.

click image to enlarge - 1.5mb
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kassy

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Re: Comet Ison, methane, noctilucents and Strat temps?
« Reply #11 on: July 05, 2021, 02:24:49 PM »
Trends in the polar summer mesosphere temperature and pressure altitude from satellite observations

Abstract
Time series of mesospheric temperature and pressure altitude are produced through combining observations by the Halogen Occultation Experiment (HALOE), Sounding of the Atmosphere Using Broadband Emission Radiometry (SABER), and Solar Occultation for Ice Experiment (SOFIE) instruments. Time series of both temperature and pressure altitude are produced through the combination of HALOE/SABER providing 29 years in length and HALOE/SOFIE providing 22 years in length. The different sampling of the three instruments constrains the time series to June in the northern hemisphere and December in the southern hemisphere and 64–70° in both hemispheres. We interpret the time series by fitting them to simple descriptions of the variations including solar, intra-hemispheric, inter-hemispheric, and linear trend terms. The inferred intra- and inter-hemispheric terms show that dynamical influences rival solar variability in the mesosphere. We find a robust result that the mesosphere is in general cooling at most altitudes at approximately 1–2 K per decade in response to greenhouse gas increases. That cooling leads to a shrinking of the atmosphere on the order of 100–200 m per decade. The shrinking leads to a reduction in cooling and eventually a warming near 0.005 hPa due to hydrostatic contraction.

...

Summary and conclusions

We have created time series of NH and SH polar summer mesospheric temperature and pressure altitude from observations
...

Using a simplified description of the variability including terms for solar, intra-hemispheric, and inter-hemispheric variations, we were able to isolate linear trends in both temperature and pressure altitude throughout the mesosphere. The inferred intra-hemispheric and inter-hemispheric terms are consistent with previous work and show that dynamical influences rival solar variability in the mesosphere. The linear term in temperature shows a negative peak in the NH near 0.03 hPa and in the SH near 0.05 hPa. In both hemispheres there is a strong positive peak near 0.005 hPa, though stronger in the NH. In both hemispheres the term approaches zero near 1 hPa. The linear trends in pressure altitude are negative at all altitudes in both hemispheres. These results are consistent with a mesosphere that is cooling at most altitudes at approximately 1–2 K per decade in response to greenhouse gas increases. That cooling leads to a shrinking of the atmosphere. The shrinking leads to a reduction in cooling and eventually a warming due to hydrostatic contraction. This warming occurs just above the altitude at which PMCs form, suggesting that PMCs form at an altitude of small temperature trends. These results present the first observational confirmation of a shrinking mesosphere. The rate of the shrinking is approximately 150–200 m per decade throughout much of the mesosphere.

https://www.sciencedirect.com/science/article/pii/S1364682621001085?via%3Dihub

PMC = Polar mesospheric cloud
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Tor Bejnar

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Re: Comet Ison, methane, noctilucents and Strat temps?
« Reply #12 on: July 06, 2021, 01:10:28 AM »
I had to look up PMC (wiki)  to figure out what it meant - I did this before I scrolled to the very bottom (last line) of your post.  Thank you very much, Kassy, for defining the term they used!
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kassy

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Re: Comet Ison, methane, noctilucents and Strat temps?
« Reply #13 on: July 06, 2021, 02:03:19 PM »
Thanks...next time i will put it above the article.  ;)
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morganism

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Re: Comet Ison, methane, noctilucents and Strat temps?
« Reply #14 on: July 26, 2021, 11:29:46 PM »

NLCs Setting Records
July 22, 2021 / Dr.Tony Phillips   

July 21, 2021: Noctilucent cloud (NLC) season is now 8 weeks old. This animation from NASA’s AIM spacecraft shows everything that has happened since the first clouds appeared in late May:

“We’re seeing more clouds at 80°N than in any other year since AIM was launched,” says Cora Randall of the University of Colorado’s Laboratory for Atmospheric and Space Research. “Cloud frequencies at 80°N are around 85%, whereas it’s more typical to see frequencies of about 75%.”

https://spaceweatherarchive.com/2021/07/22/nlcs-setting-records/