Ontwikkeling van de QBO, zonneactiviteit, ENSO, MJO en de winter 2020/2021
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- Berichten: 12344
- Lid geworden op: 31-12-1977
Re: Ontwikkeling van de QBO, zonneactiviteit, ENSO, MJO en de winter 2020/2021
MJO EC46
Je hebt niet voldoende permissies om de bijlagen van dit bericht te bekijken.
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- Berichten: 12344
- Lid geworden op: 31-12-1977
Re: Ontwikkeling van de QBO, zonneactiviteit, ENSO, MJO en de winter 2020/2021
https://www.youtube.com/watch?list=PLxf ... e=emb_logo
Serie presentaties over winterstormen.
Serie presentaties over winterstormen.
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- Berichten: 12344
- Lid geworden op: 31-12-1977
Re: Ontwikkeling van de QBO, zonneactiviteit, ENSO, MJO en de winter 2020/2021
Visie Tamara. https://www.netweather.tv/forum/topic/9 ... nt=4313966
No theory (in the true sense of the word) has been turned on its head in respect of La Nina. What has happened, as has occurred in some previous late autumns and early winter, is that a relatively active intra-seasonal high frequency tropical signal has created a rossby wave feedback that has resulted in a higher amplified downstream tropospheric pattern than would be seen in a more typical -ve frictional/mountain torque regime that represents a La Nina feedback. However, that doesn't on its own mean anything for the weeks and months to come - especially when pivotal wavelength changes will couple the NAO and AO much more closely, one way or the other, as deeper winter arrives in a few weeks
Intrinsic coupling of the Annular Mode heading into deeper winter requires more exacting forcing than seen so far - and, with a w/QBO likely to influence, once again, the most important layers of atmosphere through the winter the chances increase that a more organised westerly gyre takes over once present intra-seasonal factors diminish and the tropics cease propagating rossby wave eddies poleward to sustain the imbalance between the pole and the mid latitude. .
So, in this way, the tropospheric/stratospheric relationship can quickly can become much more stable (i.e through a much more stable GSDM relationship to the oceanic base state) This comes about by less eastward propagation of tropical forcing and greater additions of easterly wind inertia to re-configure the upstream pattern and send greater polar jet energy further downstream. This, in the absence of a top-down forcing to loop that polar jet, rather than across the mid latitudes, instead around the arctic and sustain and/or intensify an unstable profile across the polar field.
At present, while there is indication that the African/Indian Ocean low frequency standing wave present for quite some time through the summer and into the autumn is relocating/propagating east towards the Maritimes, much more evidence is required to see whether a more specific tropical convergence can set up even further east into the western/central Pacific. This, essentially, leading to a more east based La Nina pattern. Much as happened for example in 2017/18. This cycle meant that a more unstable GSDM profile persisted into the New Year and which ultimately led to the SSW in February 2018. At present, there is no clear indication, either way, what is going to happen - and angular momentum trends during the remainder of December will be pivotal in this respect.
From my point of view at 39N, where I will be residing in the next couple of weeks, it is immaterial in terms of any high impact cold weather repercussions this winter - but for those looking for winter wonderlands at latitudes further north - its always worth being aware that there is never any x+y= equation when it comes to fitting given diagnostic parameters to weather patterns
It is necessary to look at periodicity of high frequency tropical signals (the recurrence timeline) and not assume that the tropical cycle behaves like a time-clock which replicates the same on its subsequent 'mini ENSO cycle' within the next circa 30 days. These periodicity timelines extend up to circa 60 to 90 day lengths. Unlike a winter such as 2017/18 the likely persistence of a westerly QBO gyre at the most important levels of the atmosphere means that the tropospheric/stratospheric relationship is going to be also be dependant on solar assistance to de-couple ( ramifications for Brewer Dobson Circulation transport between the tropical and polar stratosphere). Equally, in tandem with US and Asian torque mechanisms getting in on the act to trigger poleward momentum transport - but then as the complexities of even the last two winters have shown where contravailing forces have mitigated the propagation of these poleward eddies, staring at stratospheric forecasts at *insert time-period* does not not inextricably make it snow even if they move forward in time.
-> Sluit goed aan bij eerdere visie Matt Hugo.
No theory (in the true sense of the word) has been turned on its head in respect of La Nina. What has happened, as has occurred in some previous late autumns and early winter, is that a relatively active intra-seasonal high frequency tropical signal has created a rossby wave feedback that has resulted in a higher amplified downstream tropospheric pattern than would be seen in a more typical -ve frictional/mountain torque regime that represents a La Nina feedback. However, that doesn't on its own mean anything for the weeks and months to come - especially when pivotal wavelength changes will couple the NAO and AO much more closely, one way or the other, as deeper winter arrives in a few weeks
Intrinsic coupling of the Annular Mode heading into deeper winter requires more exacting forcing than seen so far - and, with a w/QBO likely to influence, once again, the most important layers of atmosphere through the winter the chances increase that a more organised westerly gyre takes over once present intra-seasonal factors diminish and the tropics cease propagating rossby wave eddies poleward to sustain the imbalance between the pole and the mid latitude. .
So, in this way, the tropospheric/stratospheric relationship can quickly can become much more stable (i.e through a much more stable GSDM relationship to the oceanic base state) This comes about by less eastward propagation of tropical forcing and greater additions of easterly wind inertia to re-configure the upstream pattern and send greater polar jet energy further downstream. This, in the absence of a top-down forcing to loop that polar jet, rather than across the mid latitudes, instead around the arctic and sustain and/or intensify an unstable profile across the polar field.
At present, while there is indication that the African/Indian Ocean low frequency standing wave present for quite some time through the summer and into the autumn is relocating/propagating east towards the Maritimes, much more evidence is required to see whether a more specific tropical convergence can set up even further east into the western/central Pacific. This, essentially, leading to a more east based La Nina pattern. Much as happened for example in 2017/18. This cycle meant that a more unstable GSDM profile persisted into the New Year and which ultimately led to the SSW in February 2018. At present, there is no clear indication, either way, what is going to happen - and angular momentum trends during the remainder of December will be pivotal in this respect.
From my point of view at 39N, where I will be residing in the next couple of weeks, it is immaterial in terms of any high impact cold weather repercussions this winter - but for those looking for winter wonderlands at latitudes further north - its always worth being aware that there is never any x+y= equation when it comes to fitting given diagnostic parameters to weather patterns
It is necessary to look at periodicity of high frequency tropical signals (the recurrence timeline) and not assume that the tropical cycle behaves like a time-clock which replicates the same on its subsequent 'mini ENSO cycle' within the next circa 30 days. These periodicity timelines extend up to circa 60 to 90 day lengths. Unlike a winter such as 2017/18 the likely persistence of a westerly QBO gyre at the most important levels of the atmosphere means that the tropospheric/stratospheric relationship is going to be also be dependant on solar assistance to de-couple ( ramifications for Brewer Dobson Circulation transport between the tropical and polar stratosphere). Equally, in tandem with US and Asian torque mechanisms getting in on the act to trigger poleward momentum transport - but then as the complexities of even the last two winters have shown where contravailing forces have mitigated the propagation of these poleward eddies, staring at stratospheric forecasts at *insert time-period* does not not inextricably make it snow even if they move forward in time.
-> Sluit goed aan bij eerdere visie Matt Hugo.
Re: Ontwikkeling van de QBO, zonneactiviteit, ENSO, MJO en de winter 2020/2021
Paul schreef eens dat die visie achterhaald is. Dat kun je ook anders zien. Als er een grotere andere kracht is dan zou de visie van Matt Hugo weleens niet door kunnen gaan. Niet zo snel dingen verwerpen.....
Re: Ontwikkeling van de QBO, zonneactiviteit, ENSO, MJO en de winter 2020/2021
Bedankt Sebastiaan voor de stormenlezing. De storm in de stratosferische vortex zal de komende dagen afnemen.
De QBO- waarde op 30hpa is licht gestegen de afgelopen maand (10.80 -> 11.15).
Het beeld dat daarbij hoort in de troposfeer en stratosfeer is interessant. Op 20 hPa wordt de komende week een overgang naar oostenwinden berekend. Een verdere toename van het niveau van de QBO op 30 hPa lijkt daarom niet waarschijnlijk. Overigens is op het Noordelijk Halfrond een afname van de stratosferische vortex berekend.
De QBO- waarde op 30hpa is licht gestegen de afgelopen maand (10.80 -> 11.15).
Het beeld dat daarbij hoort in de troposfeer en stratosfeer is interessant. Op 20 hPa wordt de komende week een overgang naar oostenwinden berekend. Een verdere toename van het niveau van de QBO op 30 hPa lijkt daarom niet waarschijnlijk. Overigens is op het Noordelijk Halfrond een afname van de stratosferische vortex berekend.
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- Berichten: 12344
- Lid geworden op: 31-12-1977
Re: Ontwikkeling van de QBO, zonneactiviteit, ENSO, MJO en de winter 2020/2021
Glaam kaarten e.d. te vinden hier: https://atlas.niu.edu/gwo/
Re: Ontwikkeling van de QBO, zonneactiviteit, ENSO, MJO en de winter 2020/2021
De Glaamkaarten geven nu een bij het seizoen behorend beeld zonder significante afwijkingen.
Interessant is te lezen hoe hiermee in de periode 2000-2010 is gewerkt.
https://agupubs.onlinelibrary.wiley.com ... 06RG000213
Momenteel wordt van deze invalshoek concreet weinig gebruik gemaakt is mijn beeld. Inmiddels wordt toch veel meer van de relatie MJO fase en de circulatiepatronen op het NH gebruik gemaakt door bijvoorbeeld NOAA. Vooral in de situatie waarbij geen duidelijke ENSO fase in beeld is.
Interessant is te lezen hoe hiermee in de periode 2000-2010 is gewerkt.
https://agupubs.onlinelibrary.wiley.com ... 06RG000213
Momenteel wordt van deze invalshoek concreet weinig gebruik gemaakt is mijn beeld. Inmiddels wordt toch veel meer van de relatie MJO fase en de circulatiepatronen op het NH gebruik gemaakt door bijvoorbeeld NOAA. Vooral in de situatie waarbij geen duidelijke ENSO fase in beeld is.
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- Berichten: 12344
- Lid geworden op: 31-12-1977
Re: Ontwikkeling van de QBO, zonneactiviteit, ENSO, MJO en de winter 2020/2021
Dank Karel.
The westerly QBO is beginning to descend down to the top of the Troposphere. We'll see if it gets there but it could mean reduced or weaker MJO activity this Winter.
https://twitter.com/MJVentrice/status/1 ... 6397655040
Geen goed nieuws. We hebben een sterke MJO nodig om de basis setting (later in de winter) van La Nina te pareren.
The westerly QBO is beginning to descend down to the top of the Troposphere. We'll see if it gets there but it could mean reduced or weaker MJO activity this Winter.
https://twitter.com/MJVentrice/status/1 ... 6397655040
Geen goed nieuws. We hebben een sterke MJO nodig om de basis setting (later in de winter) van La Nina te pareren.
Je hebt niet voldoende permissies om de bijlagen van dit bericht te bekijken.
Re: Ontwikkeling van de QBO, zonneactiviteit, ENSO, MJO en de winter 2020/2021
Achterhaald? Iets te kort door de bocht. Alleen de data die een paar jaar geleden beschikbaar waren zijn dat nu niet meer. Het topic hierover op een Amerikaans forum werd opgeheven. Ik zie geen manier om de theorie te toetsen en zeker geen manier om verwachtingen mee op te stellen, ook omdat de verwachtingen springerig zijn en er ook nog een bias is. Het kan ook zijn dat ik de capaciteit niet heb om dergelijk ingewikkelde materie te begrijpen, iig gaat het verhaal dat aangehaald wordt mij grotendeels boven de pet.
Re: Ontwikkeling van de QBO, zonneactiviteit, ENSO, MJO en de winter 2020/2021
MJO: weinig amplitude nog steeds.
Je hebt niet voldoende permissies om de bijlagen van dit bericht te bekijken.
Laatst gewijzigd door Paul op 10-12-2020 19:08, 2 keer totaal gewijzigd.