Stratosphere discussion 2020

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Chris W
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Stratosphere discussion 2020

Unread post by Chris W »

Suggesting we either rename this thread or start another around general observations on and discussion about the stratosphere. I am studying it closely and it’s looking pretty interesting at the moment for these reasons:
- The forming Polar vortex does not look super-tight or stable, maybe it isn’t at this time of year in general as I’ve not studied it before the SSW.
- Ozone levels are still high up there.
- Metcheck is projecting a displacement in a week’s time at 10hPa, not sure if it can be classed as a warming but it also pushes some low heights our way. See below:
4F2CC37E-6908-4825-96B5-DA013A56DCEE.jpeg
This is how I use my lockdown time!
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Chris W
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Re: Stratosphere discussion 2020

Unread post by Chris W »

Tell me if I’m wrong, but is this a weak SSW in autumn:
74621CF9-D69E-4E5F-93FE-6FAFA66ACF56.png
NOAA certainly have a lot of charts to get one’s head around at https://www.cpc.ncep.noaa.gov/

The stratosphere at 10hPa seems to be tracking slightly cooler than average, but warmer at lower levels.
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Re: Stratosphere discussion 2020

Unread post by TonyT »

March global lower stratospheric temperatures climb a little higher above the long term normal, re-inforcing the ideas CT discussed last month in the Sudden Stratospheric Warming thread. (Image from Dr Roy Spencer's blog)
Cyclone Tracy wrote: Sat 14/03/2020 12:20 February data has come in overnight from NOAA. This is now the most significant stratospheric temperature change since the Mt Pinatubo eruption in early 1990’s :crazy: . According to the NOAA data set, the global stratosphere has continued to warm since November 2019 to now the highest temperature level since 1993.

Mt Pinatubo’s eruption took 6 weeks to commence changing the stratosphere’s global temperature. The mass influx of Ozone over Antarctica in late October from the SSW correlates to the initial movement of this new temperature spike. Then the Australian bush fires peaked in mid to late December (Hectares burnt). 2 major air chemistry events seems to have triggered this change. It took Mt Pinatubo’s eruption 6 months to start dropping the earth’s surface temperature. Interesting observations ahead in the coming months :smile:
Cyclone Tracy wrote: Thu 26/03/2020 20:03 and just to add to that as well...…

Based on the previous 2 stratospheric positive temperature anomaly timelines from the large volcanic eruptions of 1982 & 1991, an affect on the surface temperature could commence within the next 2 months. This is based on the local energy equilibrium thermodynamics theory of the stratosphere and troposphere offsetting each other (one warms while the other cools and vice versa). More will be known once we see the March temperatures for the stratosphere released by NOAA in the coming weeks.
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Re: Stratosphere discussion 2020

Unread post by Chris W »

GFS is continually modelling areas of high ozone between South Africa and south of Australia/NZ over the Southern Ocean, in fact they are there right now and have been for a couple of weeks. This serves to warm and displace the stratospheric vortex towards South America, similar to the SSW and doubtless related. This serves to keep the vortex on this side of the pole tight and close to the East Antarctic Ice Sheet until it approaches NZ, then it becomes slacker and allows airflow in our direction. To my mind this sets us up for more of a southwesterly-tracking tropospheric jet in May and maybe June.

https://www.cpc.ncep.noaa.gov/products/ ... sh_f00.png
E4AD8C16-7942-479A-838A-4364E2FC8A26.png
703EA123-55C8-4D5C-B5B8-06E2BDBA5C9E.png
Still using Metcheck to view height charts for 10hPa https://www.metcheck.com/SEASONAL/strat ... ecasts.asp
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Re: Stratosphere discussion 2020

Unread post by Cyclone Tracy »

The full suite of satellite data is now published on NOAA. As per Tony's 5th April post from the UAH graph, both RSS and NESDIS now confirm with UAH that the global stratosphere is at an elevated temperature not seen since March 1993 when the Mt Pinatubo effect was still in flux. In the satellite era, this is a historic temperature change in such a short period from September's sudden stratospheric warming, Octobers' Ozone influx and December's OZ bushfire peak. Popcorn time indeed :popcorn:
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Re: Stratosphere discussion 2020

Unread post by Awhituobs »

what caused the warming in the 80s?
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Re: Stratosphere discussion 2020

Unread post by Cyclone Tracy »

Mexico's El Chichon eruption in 1982 caused the early to mid 80's spike before settling back until Mt Pinatubo's eruption in 1991.
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Re: Stratosphere discussion 2020

Unread post by TonyT »

15 volcanoes have erupted so far this month.
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Re: Stratosphere discussion 2020

Unread post by Razor »

TonyT wrote: Tue 14/04/2020 17:03 15 volcanoes have erupted so far this month.
Is that the norm?
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Re: Stratosphere discussion 2020

Unread post by Razor »

Razor wrote: Tue 14/04/2020 17:11
TonyT wrote: Tue 14/04/2020 17:03 15 volcanoes have erupted so far this month.
Is that the norm?
I answered my own question- 50 to 70 per annum

https://www.volcanodiscovery.com/volcan ... -year.html
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Re: Stratosphere discussion 2020

Unread post by TonyT »

Razor wrote: Tue 14/04/2020 17:11
TonyT wrote: Tue 14/04/2020 17:03 15 volcanoes have erupted so far this month.
Is that the norm?
Mr Google tell us that on average about 50-70 volcanoes erupt each year (some more than once), so a long term figure of about 4-6 per month would seem about right. The number is usually higher around the time of solar minimum. There were 73 eruptions in 2019 from 70 different volcanoes.
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Re: Stratosphere discussion 2020

Unread post by Chris W »

CT, Tony (indeed anyone else), can I ping you for some prognostications on the influence of this on our winter down here in the troposphere? All I have read seems to suggest negative AAO, cooler and stormier. Looking at the chart CT posted, my first year in NZ was 2013-14 and that was a wild ride from June 2013 onwards!

Couldn’t comment on any link between volcanic eruptions and solar cycles. Wouldn’t it be interesting if Ruapehu were to go however...just saying...

Looking at the temperature and wind profiles for 10 and 50hPa, at 10 the vortex (first image below) is tighter but displaced with a 15C differential from the East Antarctic ice sheet edge (-50C) to west of South America (-65C) whereas at 50 (second image) it is very spread out and not all that vigorous likely due to the many warm patches seemingly created by the higher ozone levels. Popcorn indeed!
1F936F8E-324C-4025-802D-B12BE90176F6.png
01EE411F-8EAE-4189-91C4-211E6A398445.png
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Last edited by Chris W on Tue 14/04/2020 21:22, edited 1 time in total.
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TonyT
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Re: Stratosphere discussion 2020

Unread post by TonyT »

Stratospheric stuff not my thing sorry. As I said before a warmer stratosphere is usually associated with a cooler troposphere. So far thats not happening, but then it would be likely that a lag is involved. If a Nina gets going as seems increasingly likely then that will cool the troposphere over the next 6 months. Is that two independent factors acting together? Or is one driving the other? Or is something else driving both? Cant say, but stay tuned.
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Re: Stratosphere discussion 2020

Unread post by Cyclone Tracy »

Chris W wrote: Tue 14/04/2020 17:52 CT, Tony (indeed anyone else), can I ping you for some prognostications on the influence of this on our winter down here in the troposphere?
Here is a historical look at the SAM index with the yellow highlight bars indicating to when the last time the stratosphere had heated to this level globally. There were negative SAM's in these periods but nothing really out of the ordinary. To me there is no clear link with the 2.

But here is an interesting fact from an NZ point of view. Both the global stratospheric warming events of 1982/83 & 1991-93 correlate to the sharp drops in surface temperatures for NZ. Here is the 7 station composite anomaly showing well below the 1980 to 2010 average. The 1992 7 station anomaly was the coldest year recorded in NZ since 1931.

1982 = -0.49c
1983 = -0.58c

1991 = -0.44c
1992 = -1.13c
1993 = -0.77c

(temp source NIWA)
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TonyT
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Re: Stratosphere discussion 2020

Unread post by TonyT »

82/83 and 91/93 both strong El Nino events. Strong El Nino = southwest airflow anomaly = colder than normal air over New Zealand. So, maybe a Nina is not so likely this year after all, or perhaps there is a 6-12 month lag, and this coming Nina will be brief and we go into humungo Nina this time next year in time for the 21/22 summer. Which would fit with the expected strong Nino which usually comes once the solar cycle picks up. Oh how I love these crystal balls. #-o :D :B
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Re: Stratosphere discussion 2020

Unread post by Chris W »

So you’re saying there’s a chance...of just about anything! Joke, just had to do it. 😀 I have repeatedly read that ENSO forecasting in autumn is hard...but before I mix threads too much I’ll stop there.

Fascinating, a number of variables clearly in play. Clearly we do have a stratospheric disturbance but whether other tropospheric influences will impact our winter (and beyond) weather more strongly will just remain to be seen.

So, CT, I’ll join you.

:popcorn:
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Re: Stratosphere discussion 2020

Unread post by Awhituobs »

what about the clearer skies around the world now and even less chemtrails from aeroplanes
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Re: Stratosphere discussion 2020

Unread post by Chris W »

More heat to rise to the stratosphere and be retained there by the ozone, but greenhouse gas concentrations probably don’t change that quickly.

(See correction below!)
Last edited by Chris W on Tue 14/04/2020 22:30, edited 1 time in total.
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Re: Stratosphere discussion 2020

Unread post by TonyT »

Awhituobs wrote: Tue 14/04/2020 21:41 what about the clearer skies around the world now and even less chemtrails from aeroplanes
Clearer air in the troposphere should aid long wave radiation loss, so would be a net cooling, but I imagine the affect to be very small.
Chris W wrote: Tue 14/04/2020 21:47 More heat to rise to the stratosphere and be retained there by the ozone, but greenhouse gas concentrations probably don’t change that quickly.
You need to re-think your assumptions. Heat doesn't rise from the troposphere to the stratosphere, and the mechanism via which ozone makes the stratosphere warmer is not because it retains heat generated elsewhere.
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Re: Stratosphere discussion 2020

Unread post by Chris W »

Good point, as you've pointed out I meant longwave radiation that would otherwise be trapped by the marginal amount of greenhouse gases we are not currently emitting. Bad phrasing. So my assumptions are fine, it's just been a busy day.

"The ozone hole itself has a minor cooling effect (about 2 percent of the warming effect of greenhouses gases) because ozone in the stratosphere absorbs heat radiated to space by gases in a lower layer of Earth’s atmosphere (the upper troposphere). The loss of ozone means slightly more heat can escape into space from that region."
https://earthobservatory.nasa.gov/blogs ... g-related/
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Re: Stratosphere discussion 2020

Unread post by treetop »

Especially Northern Hemisphere may head towards their coolest year for a while with clearer skies and lower carbon emissions , some interesting photography comparisons [last year/ this year] We will see how much impact any heat waves will have in the coming months . Icelandic volcanic activity forcast to increase as well which will contribute. ie high altitude pollution cools / low alt pollution heats and stores heat. Rainfall there will depend on Jet stream activity. An interesting year , bad for us good for the planet
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Re: Stratosphere discussion 2020

Unread post by Cyclone Tracy »

Just for clarity, especially for the timeline. The current global stratospheric temperature spike commenced it's warming ascent from December 2019, 6 to 8 weeks after the mass Ozone influx over South Pole and has continued to climb from the peak of the Australian bush fires. The lag on temperature from air chemistry changes in the global stratosphere is around 2 months. Reduced global air travel and the global slowdown associated with COVID-19 didn't commence until February.
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Re: Stratosphere discussion 2020

Unread post by Chris W »

Really the severe decline in travel started in March, so any impact would potentially be seen from next month. Of course planes fly in both the troposphere and stratosphere, emitting a lot near the surface on takeoff so there be differential effects there compared to fuel emissions as they cruise in the stratosphere.
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Re: Stratosphere discussion 2020

Unread post by TonyT »

Chris W wrote: Wed 15/04/2020 11:15 Really the severe decline in travel started in March, so any impact would potentially be seen from next month. Of course planes fly in both the troposphere and stratosphere, emitting a lot near the surface on takeoff so there be differential effects there compared to fuel emissions as they cruise in the stratosphere.
The main impact on air quality won't be from planes but from surface transport and industry. Thats why the air looks clearer.
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Re: Stratosphere discussion 2020

Unread post by Chris W »

Here’s the current wind field at 70hPa, following around the edge of the broad polar stratospheric pool of air that is warmer (-50C outer edge to -65C over the pole) than at tropical latitudes (-65C Southern edge to -75C towards the equator). The 250mb jet is largely following the boundary of these two, the outer edge of the polar wind field.
DEA6E654-9D9D-46EC-A71C-32311B9B5C46.png
https://earth.nullschool.net/#current/w ... 36,-79.976

This has been developing since March, and I believe the impacts are trickling down to the troposphere, though of course tropical factors such as ENSO and the IOD have their influence on things from the north. However, the SAM continues to trend negative overall as the observed pattern show below (black line). I see the ensemble members that want to take it sharply positive again, but they have been varying a lot and we know the models are struggling right now. However we can’t rule out a positive change there.
B396FC04-11E9-48C2-9466-2BDAF45B1FA0.jpeg
https://www.cpc.ncep.noaa.gov/products/ ... .sprd2.gif
https://www.cpc.ncep.noaa.gov/products/ ... .aao.shtml

GFS continues to hold the stratospheric pattern in a similar manner throughout its run, maybe with a bit of a contraction in a couple of weeks away from NZ as the warm area between South America and Australia moves in our direction.

I don’t want to read too much into this, more to present the data for discussion and study. My bias is to see cold in this and I’m interested to see how May and June go at the surface.
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