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Technical General Stratospheric Observations

Discussion in 'Systems & Severe' started by crikey, Jul 6, 2019.

  1. crikey

    crikey Addicted

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    On the 1st and 2nd July 2019
    The extensive warm AND cool pool thermocline at 50hpa was observed as waning.
    Thought the event trigger? was all over.



    So we started observing recording 'roll on' effects in the atmosphere
    We now have a re emergence of these temperature anomalies in the upper stratosphere and to be honest l am not sure if the cause is above the anomaly or below it.

    and by the 8th July we have another thermocline anomaly.
    One side is higher than the other?
    Note the 7th July is when we saw the 'split' in polar vortex'



    Thanks to the AWF watchers who pointed this out
    http://www.theaustralianweatherforum.com/forum/viewtopic.php?f=3&p=111316#p111316

    EDDY.. HEAT FLUX..?
    what is going on here?

     
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  2. snowbarbie

    snowbarbie Hard Yards

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    psv = polar stratospheric vortex
    EP flux = Eliassen Palm flux

    Imv the warm anomaly was the result of wave breaking outside the psv. You can see this in the figure below which shows EP flux vectors heading equatorwards. 14 July isn't released yet - I would be suprised if it shows anything much different.

    [​IMG]

    The warming should also appear outside the psv.

    As far as weakening of psv goes I think wave penetration has to be directly towards the interior - what is happening I think, in this example, is the wave is deflected by the steep pv(potential vorticity) gradient at the psv's edge.

    Btw Crikey, are you ok with a re-organisation of the content in this thread coming under a broader umbrella like "stratosphere" (with various sub-threads)?
     
  3. crikey

    crikey Addicted

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    I cannot comment on your analysis because at this stage l don't undestand those concepts well enough.
    Including wave propogation..in the stratosphere
    I was taken by the extent of that current eddy flux anomaly. It is right across the latitudes from polar to equator and is deep from 1tom20hpa

    If you wish to take any content from this thread and post it into another , l have no objections.
    As l said this is a case study rather than a general discussion.
    I will continue to 'puddle along here whilst the event is in play
    regards
     
  4. crikey

    crikey Addicted

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    Considering the stratosphere anomalies are still in play after the centre of the polar vortex split. I am reluctant to say l,am currently observing the recovery phase but none the less some obs',16th July 2019
    Jetstream
    200hpa...
    my notes..
    '
    I think it is fair to say that wave activity in both the polar and sub polar jets has returned.since the centre vortex split of the 7th July
    The sub tropical jet speed remains strong and is showing some weak amplitude, whilst the sub polar jet is meridonal but weak in speed still.
    As far as l understand, wavy jetstream is a result of a a reduced temp’ gradient between Hadley and Ferrel cells and Ferrel and Polar cells.'

    source
    http://www.bom.gov.au/australia/cha...=AEDT&area=G&model=G&chartSubmit=Refresh+View
     
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  5. crikey

    crikey Addicted

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    15th JULY 2019.
    SH surface synoptic update

    There are some protrusions of the westerly belt reflected in the AAO negative index of
    minus 2.2 today
    All quite normal for the westerly belt here.
    So is the high pressure centre over then pole with the sub polar cells rotating.West to east.

    Of note is what may be evidence of omega blocking which apparently is often noted after polar vortex split in the NH

    https://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/aao/.
    ..................

    Also.....thanks to @MegaMatch who posted this animation of a high pressure blocking feature on the SH synoptic
    17th to 19th July 2019


    source
    https://www.ski.com.au/xf/threads/ne-nsw-se-qld-weather.85082/page-4

     
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  6. snowbarbie

    snowbarbie Hard Yards

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    I dont think the extent of the EP flux should be taken from the chart I posted. CPC puts out a monthly anomalous EP flux - I'll try and post it for July when it comes out. The chart above only shows vectors which are scaled up for display purposes. The latest warming - like the one commented earlier in the thread from the Tokoyo Climate Centre chart(25c)- doesn't seem to have penetrated the psv - which is what I think it shows - but to be fair I'll look at the chart for the 14th when it comes available.


    Dont see there's much point in starting another thread since we're the principal posters on the topic though if the moderators decided to tidy this thread up by putting it under a broader umbrella - I can see the point in doing that.
     
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  7. crikey

    crikey Addicted

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    I think your idea @snowbarbie for another more general thread for stratosphere is a good idea.
    Posting current and past obs' and discussion on the stratosphere 1 to 200hpa in both north and southern hemispheres.

    I would fit into general and world weather nicely.
    The climate driver thread is there as well. But the stratosphere is not only a driver but an important atmospheric layer

    How about a title like
    'Stratosphere obs' and discussion'

    Thats broad enough for a low traffic thread and ok for those who like a bit of technical stuff on this forum

    What do you think?
     
  8. Jellybeans

    Jellybeans not woke enough Ski Pass: Gold

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    I think @snowbarbie’s point is that this thread should just turn into a General Stratospheric thread to save formalities and to be concise with thread-making.

    Could you change the name of the thread or could @Claude Cat change it?
     
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  9. crikey

    crikey Addicted

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    I object because a split in the centre of a polar vortex is unique event that should be documented . That is like lumping the best snow event thread into a general chat thread or putting a notable TC into tropical chat.
     
  10. crikey

    crikey Addicted

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  11. Claude Cat

    Claude Cat On my bike Moderator Ski Pass: Platinum

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    I suggest a new thread is started for General Stratospheric Observations, and leave this "as is".
     
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  12. crikey

    crikey Addicted

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    Ok Claude. Discussion here ended.
    I might have a go in the bear pit. and see how l fair?
    BTW
    whilst the furniture is being re arranged.
    Following on from the spirit of this discussion.,Close the Mt Sinabung thread as well and make a new one.
    'Volcanoes and effect on weather.' Send it to the bear pit. .
     
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  13. Claude Cat

    Claude Cat On my bike Moderator Ski Pass: Platinum

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    I have no vested interest, you guys tell me what you want to do ;)
     
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  14. POW_hungry

    POW_hungry Old n' Crusty Moderator Ski Pass: Gold

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    Never flew your tin can <200mb?;)
    Keeping this discussion broad & in one-place is critical for both obs/timeline winter events.
    I am all for re-naming: General Stratospheric Observations
     
  15. crikey

    crikey Addicted

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    Look ..,to keep the peace .,Change the title. @claudecat
    There is only a handful of people contributing here and l am over ruled and a new kid on the block.

    But... please put my Volcano and effects on weather thread in the bear pit where it belongs.
     
  16. Kino

    Kino Early Days

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    So the said impact of the SSW / Antarctic Polar Vortex split for the east coast seems to be endless shortwave troughs with gale force w/sw winds. Oh yay. Not. Next one due tomorrow PM.
     
  17. crikey

    crikey Addicted

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    I believe your assessment of the impact of stratospheric anomalies and possibly associated formation of 2 low pressure vortices over the subpolar and polar region is correct.
    There is nothing in my obs' from this event that supports enhanced snowfall .Quite the contrary actually
    The sub polar jet has been out of action and the recent snow dump was assisted by a northerly excursion of the westerly belt with an embedded low.
    and associated well positioned high.
    There are some surface features l have observed that have assisted your recent snow dump. But that discussion would be off topic.
    We are currently 10days on from the central vortex split. today.
    I will read that 2002 vortex split documentation you posted today @Kino.
     
  18. MegaMatch

    MegaMatch One of Us Ski Pass: Silver

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    Gee the Pacific is such a dog's breakfast. A continuation of omega blocks with huge cold pools continuing to dart up from the south. Meanwhile, you compare this to somewhere like the southern Indian Ocean where the pattern is much more progressive...chalk and cheese.
     
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  19. Jellybeans

    Jellybeans not woke enough Ski Pass: Gold

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    Because it's not actually a significant stratospheric event. Because it is not a split.
    The -AAO (which brought about the system a few days back) is from a number of other causes.
     
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  20. crikey

    crikey Addicted

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    There is quite a bit on the www about the 2002 event.
    The journal article below is open for anyone to read.
    It was published 4yrs after the event.
    ........
    thanks to ‘kino’ from ski..com for finding this documentation of the one an only other polar vortex split in 2002

    Geophysical Research Letters banner
    Atmospheric Science Free Access
    The Antarctic stratospheric sudden warming of 2002: A self‐tuned resonance?
    J. G. Esler
    L. M. Polvani
    R. K. Scott
    First published: 21 June 2006

    https://doi.org/10.1029/2006GL026034

    https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2006GL026034

    1. Introduction

    [2] The remarkable Antarctic stratospheric sudden warming of 2002 has attracted great interest amongst the atmospheric science community (e.g., Journal of Atmospheric Science, 2005, 62(3)), primarily because such an event is unprecedented in roughly 50 years of observations. Between September 23 and September 26, above the 600 K isentropic level (∼26 km), the stratospheric vortex was observed to split into two parts [Charlton et al., 2005], and the attendant higher polar temperatures had a dramatic impact on subsequent chemistry with substantially reduced ozone depletion [Stolarski et al., 2005]. A detailed understanding of such significant events is therefore necessary in order to assess the likelihood of future occurrences, with the attendant consequences on the Antarctic ozone

    [​IMG]
     
  21. Jellybeans

    Jellybeans not woke enough Ski Pass: Gold

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    Have a look here @crikey

    A few mates and I have come up with a collation of research papers and model resources for people to use. There’s some papers on the 2002 SSW, because I remember posting about it a while back.
     
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  22. crikey

    crikey Addicted

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    following on from above post
    So did a SSW and polar vortex split affect snow levels in 2002?

    2002 snow depth spencer creek.
    Nothing fancy 180cm

    https://www.sbs.com.au/interactive/2015/kosciuszko-snow-depth/

    I never claimed the SSW and polar vortex split would produce abundant cold pools or snow dumps.
    When some one asked me that question on page 1. I said , l didn't know.

    Know l do know.
     
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  23. snowbarbie

    snowbarbie Hard Yards

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    I think the various papers need to be read. Conflating 2002 split with what has happened recently may be misleading - I'm sure that's been mentioned before. What about evidence? Level by level -a detailed analysis which would be irrefutable - I wouldn't argue with that.
     
  24. snowbarbie

    snowbarbie Hard Yards

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    Here's the EP flux charting for 14th July. Vectors show vertical wave propagation in troposphere. Doesn't seem to penetrate the tropopause - but is turned equatorward higher in stratosphere. Solid contours at about 300hpa, 30 south and ~60 south represent de-accelaration of westerly jet.

    [​IMG]find gas near me
     
  25. snowbarbie

    snowbarbie Hard Yards

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    Correcting that - there's a bit of a mix of vertical and meridional propagation in the lower troposphere then it tends to just meridional higher up before resuming upwards in the lower stratosphere and it does seem to be outside the psv
     
  26. Jellybeans

    Jellybeans not woke enough Ski Pass: Gold

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  27. snowbarbie

    snowbarbie Hard Yards

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  28. Kino

    Kino Early Days

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    Added to that, planetary waves off the Andes...fascinating.
     
  29. snowbarbie

    snowbarbie Hard Yards

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    Apologies to all for this- just spotted. For some reason the ESRL EP flux chart jumps inexplicably to 2015 as soon as I button for divergence on the page. I have no idea why it is happening -whether it's an onsite bug or at my end. It's a pity because divergence/convergence can show a bit more to what is going on.
     
  30. Kino

    Kino Early Days

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    So, what're the causes of planetary waves from the Andes? Storms? Short/long waves? Geostrophic winds?
     
  31. snowbarbie

    snowbarbie Hard Yards

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    Eddy Heat Flux forecast @ 24 and 48 hours showing increasing negative eddy heat flux spawned over south atlantic - the flow is downward from higher stratosphere - may be response to events described by SnowyHibbo on https://www.33andrain.com (Teleconnections -Technical discussion, but you may have to register to access ). Alternately try his blog(see post Jellybeans above) though I dont think it is as comprehensive on this particular instance as his forum post at 33andrain.

    24 hours
    [​IMG]

    48
    [​IMG]

    Negative eddy heat flux perhaps illustrating downward reflection of zonal wave involved(wave 1?) which looks forecasted to land above 10hPa.

    Big learning curve on this for me and any comment or critique is welcome.
     
  32. snowbarbie

    snowbarbie Hard Yards

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    All of the above I think if they are not causes would be encompassed by the Global Synoptic Dynamic Model which SnowyHibbo and others at 33andrain are well documenting especially for learners. Not meant to be a cute answer btw. I can only positively encourage everyone with an interest to follow this up themselves - perhaps a GSDM thread will be warranted in future.
     
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  33. Jellybeans

    Jellybeans not woke enough Ski Pass: Gold

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    Not sure if you saw this from the Winter thread:
     
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  34. Kletterer

    Kletterer Thredbo Doughnut Tragic Moderator

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    Interesting.
     
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  35. Kletterer

    Kletterer Thredbo Doughnut Tragic Moderator

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    So are we looking at Jet sourced waves propogating upwards and downwards from the Jet Core ?
     
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  36. Jellybeans

    Jellybeans not woke enough Ski Pass: Gold

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    Yep the blog is a more general take for snow forecasting purposes, the post on 33andrain (and now here) is more for technical predictions user for wider climate driver forecasting.

    I am going to be double posting when it is important to here, thanks to these new technical threads. But of course, not to be selfish or anything, but there is a large resource for this sort of stuff there at 33andrain.
     
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  37. Kino

    Kino Early Days

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    Many thanks & no - hence the question and why on-topic discussion helps heaps.
     
  38. POW_hungry

    POW_hungry Old n' Crusty Moderator Ski Pass: Gold

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    Looking stronger again on EC today. I think this one might be warmer than the last.

    Looks like it will re-instate the Southern Pac blocking High, which looks to even force cold core, cut-off lows north of it. Impressively staunch.
     
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  39. POW_hungry

    POW_hungry Old n' Crusty Moderator Ski Pass: Gold

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    Warming trend has been obs-ed by JMA yesterday:

    "10-hPa temperature change in a week in the Southern Hemisphere
    The contour interval is 5 °C. The pink and light blue shadings indicate warming and cooling, respectively. The red shading denotes warming for values higher than 25 °C."
    [​IMG]
     
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  40. snowbarbie

    snowbarbie Hard Yards

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  41. snowbarbie

    snowbarbie Hard Yards

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    interesting to see a high cell@10hpa develops & migrates eastward in the GFS forecast . Another cell forms over the south atlantic and follows in somewhat similar direction and in tandem these two cells on either side "squish" the spv so that it's a little more elliptical than usual, and the longer axis looks poised to rotate much closer to aus for the period which I think Snowy Hibbo blog marked as potentially favorable time for snowfall

    [​IMG]
     
  42. crikey

    crikey Addicted

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  43. POW_hungry

    POW_hungry Old n' Crusty Moderator Ski Pass: Gold

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    JMA Observed.
     
  44. snowbarbie

    snowbarbie Hard Yards

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    Wonder if that cooling may've been associated with very low O3 moving outside the polar night perimeter and mixing into the collar region - reducing heat transfer from a reduced O3 content, and dampening longwave heating from the earth .

    Position at 17July
    [​IMG]


    Position at 22 July
    [​IMG]
     
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  45. Jellybeans

    Jellybeans not woke enough Ski Pass: Gold

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    You can bet good money that it is.
    Good find.

    Interesting because I thought the BDC (the conveyor of ozone in the upper atmosphere) was strong. Must have tapered off.
     
  46. snowbarbie

    snowbarbie Hard Yards

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    Little anomalous circulation pattern in vicinity of exchange of streak of O3 rich air from surf zone for low O3 from spv interior, looks involved, as zonal flow converges on Andes.

    [​IMG]

    [​IMG]
     
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  47. snowbarbie

    snowbarbie Hard Yards

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    My conclusion is that Brewer Dobson would be currently weak.

    Reasoning - only using chart below - so has to be subject to updated data with better resolution. Comments only apply to SH
    [​IMG]
    If you look at the period prior to the late 90's the deficit of O3 in the tropics would suggest a strengthened phase of bdc - confirmed by the +ve anoms in the collar region for same period

    (broadly speaking) since then the trend has been the reverse - a weakening bdc. On shorter timescale 2017-18 looks to turn that weakening trend around somewhat - with the largest tropical deficit since about 2010(and corresponding O3 nearer to climatology in the 30-50 zone). I don't know that this slight reversal in weakening bdc, is continuing though. There's currently a large +ve anom in the tropical stratosphere and though the current anoms at 30-50 don't show it - perhaps because of time lag in O3 transport - I would anticipate that collar region O3 would, in short term future, start to show significant deficit again.
     
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  48. 7V2vsqT - Imgur (1).png

    Will we see 40-60+c and then see a split.
     
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  49. Kletterer

    Kletterer Thredbo Doughnut Tragic Moderator

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    Heights and Temps on the 8th Aug.
     
  50. Jellybeans

    Jellybeans not woke enough Ski Pass: Gold

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    But do we think we have a full SSW?