Stratosfeer 2022/2023

[Sebastiaan]

En daarmee heeft RvdB zijn revanche.

[Karel]

Wave-1 zonder SSW betekent dit jaar eerst kou in Azië https://japantoday.com/category/nationa ... s-canceled en de komende weken in Noord-Amerika. Hier de bekende februari situatie in La Niña winters.

[Sebastiaan]

Extreme states of the stratospheric polar vortex can have long-lasting impacts on extratropical circulation patterns, such as the North Atlantic Oscillation (NAO). This provides windows of subseasonal predictability beyond the typical weather forecast horizon of about 10 days. Subseasonal forecasts of surface weather are of significant interest in weather-dependent socio-economic sectors. For example, demand and supply for electricity and gas are weather dependent and therefore accurate forecasts are important for the energy industry and energy trading. Here we investigate the subseasonal impact of stratospheric conditions on surface weather events relevant to the energy industry in five subregions of Europe in winter. We use a definition of seven Atlantic–European weather regimes to describe the variability of the large-scale circulation on subseasonal time scales. Results indicate that weather events are often associated with more than one preferred weather regime. In turn, some weather regimes project onto a specific NAO phase, while others are independent of the NAO. As expected, anomalous stratospheric polar vortex states predominantly modulate the occurrence of regimes related to the NAO and affect the likelihood of their associated weather events. In contrast, the occurrence of weather regimes which do not project well onto the NAO is not affected by anomalous stratospheric polar vortex states. These regimes provide pathways to unexpected weather events in extreme stratospheric polar vortex states. For example, weak stratospheric polar vortex states enhance the likelihood of negative NAO. High wind events in Central Europe predominantly occur during the zonal regime, strongly projecting onto positive NAO. However, these events also occur during the Atlantic trough regime, which is unaffected by anomalous stratospheric polar vortex states and thus provides a pathway to Central European high wind events during weak stratospheric polar vortex states. A correct NAO prediction alone is therefore not sufficient to correctly predict surface weather after extreme stratospheric polar vortex states. Moreover, weather regime life cycles independent of the NAO also need to be forecast accurately. https://rmets.onlinelibrary.wiley.com/d ... 02/qj.3653

[Karel]

Extreme states of the stratospheric polar vortex can have long-lasting impacts on extratropical circulation patterns, such as the North Atlantic Oscillation (NAO). This provides windows of subseasonal predictability beyond the typical weather forecast horizon of about 10 days. Subseasonal forecasts of surface weather are of significant interest in weather-dependent socio-economic sectors. For example, demand and supply for electricity and gas are weather dependent and therefore accurate forecasts are important for the energy industry and energy trading. Here we investigate the subseasonal impact of stratospheric conditions on surface weather events relevant to the energy industry in five subregions of Europe in winter. We use a definition of seven Atlantic–European weather regimes to describe the variability of the large-scale circulation on subseasonal time scales. Results indicate that weather events are often associated with more than one preferred weather regime. In turn, some weather regimes project onto a specific NAO phase, while others are independent of the NAO. As expected, anomalous stratospheric polar vortex states predominantly modulate the occurrence of regimes related to the NAO and affect the likelihood of their associated weather events. In contrast, the occurrence of weather regimes which do not project well onto the NAO is not affected by anomalous stratospheric polar vortex states. These regimes provide pathways to unexpected weather events in extreme stratospheric polar vortex states. For example, weak stratospheric polar vortex states enhance the likelihood of negative NAO. High wind events in Central Europe predominantly occur during the zonal regime, strongly projecting onto positive NAO. However, these events also occur during the Atlantic trough regime, which is unaffected by anomalous stratospheric polar vortex states and thus provides a pathway to Central European high wind events during weak stratospheric polar vortex states. A correct NAO prediction alone is therefore not sufficient to correctly predict surface weather after extreme stratospheric polar vortex states. Moreover, weather regime life cycles independent of the NAO also need to be forecast accurately. https://rmets.onlinelibrary.wiley.com/d ... 02/qj.3653

Interessante studie Sebastaan.

Scandinavian Blocking (winterweer met kans op vorst van betekenis ) komt dus ook voor bij NAO+, maar komt in de winter gemiddeld in de periode 1979-2015 het minst van de zeven circulatietypen voor (6,5%). Dit ciculatietype wordt niet beinvloed door een warme stratosfeer. Dat geldt wel voor Greenland Blocking dat meer voorkomt in de winters van 1979-2015 (11,7%) Winters weer met hagel en (natte) sneeuwbuien.


500-hPa geopotential height anomaly (Z500', shading, every 20 gpm)

[Paul]

https://rmets.onlinelibrary.wiley.com/d ... 02/qj.3653

Dit is waar het om draait voor wat betreft de stratosferische impact op de circulatie. Zeer relevant.

Naamloos.png

[Sebastiaan]

https://rmets.onlinelibrary.wiley.com/d ... 02/qj.3653

Dit is waar het om draait voor wat betreft de stratosferische impact op de circulatie. Zeer relevant.

Naamloos.png

Ja. Je ziet nauwelijks Scandihogen bij sterke strat. poolwervel. En flink meer zonaal en scandi trog bij sterke stra. poolwervel
En veel meer GL hogen bij zwakke strat. poolwervel.

[Sebastiaan]

https://www.nature.com/articles/s41612-022-00275-1#Sec6

Northern Hemisphere (NH) climate has experienced various coherent wintertime multidecadal climate trends in stratosphere, troposphere, ocean, and cryosphere. However, the overall mechanistic framework linking these trends is not well established. Here we show, using long-term transient forced coupled climate simulation, that large parts of the coherent NH-multidecadal changes can be understood within a damped coupled stratosphere/troposphere/ocean-oscillation framework. Wave-induced downward propagating positive stratosphere/troposphere-coupled Northern Annular Mode (NAM) and associated stratospheric cooling initiate delayed thermohaline strengthening of Atlantic overturning circulation and extratropical Atlantic-gyres. These increase the poleward oceanic heat transport leading to Arctic sea-ice melting, Arctic warming amplification, and large-scale Atlantic warming, which in turn initiates wave-induced downward propagating negative NAM and stratospheric warming and therefore reverse the oscillation phase. This coupled variability improves the performance of statistical models, which project further weakening of North Atlantic Oscillation, North Atlantic cooling and hiatus in wintertime North Atlantic-Arctic sea-ice and global surface temperature just like the 1950s–1970s.

[Sebastiaan]

https://charts.ecmwf.int/products/exten ... 2301300000

Een behoorlijk deel van het ENS gaat voor een SSW. Mogelijk heeft dat gevolgen voor de lente.

[Paul]

Het zit ook in de pluim van GFS.
Nieuwe heatflux half februari.
De huidige displacement, hoewel geen SSW, heeft mogelijk toch gevolgen in de vorm van een verzwakking van de zonaliteit en de opbouw van hogedruk boven onze omgeving. EC46 biedt steun.

Naamloos4.png

Naamloos3.png

[Sebastiaan]

https://agupubs.onlinelibrary.wiley.com ... 19GL084683
https://twitter.com/Petagna/status/1620 ... ajkP0sAAAA