Hier een publikatie over de methode om de centrale datum te vinden voor de stratosfeer/troposfeer koppeling bij een SSW. Niet uitgaan van de centrale datum van de SSW.Sebastiaan schreef: ↑06-01-2021 09:39Downwelling vindt continu plaats, op dag 10 zelfs stevige oostelijke winden hoog in de atmosfeer. Die zouden ook moeten downwellen. Zorgen zij voor de echte klapper?
Tracking the stratosphere‐to‐surface impact of Sudden Stratospheric Warmings
Richard J. Hall e.a
https://agupubs.onlinelibrary.wiley.com ... 20JD033881
https://agupubs.onlinelibrary.wiley.com ... I-S01.docx
"Abstract
Sudden stratospheric warming (SSW) events are extreme atmospheric regimes which can have a signature in surface weather up to 40 days after event onset in the stratosphere. SSWs can be classified as either vortex splitting or vortex displacement events, with the nature and timing of the surface impact potentially being different between the two. In this study, using ERA40/Interim reanalysis data, we develop a simple empirical downward tracking algorithm which for the first time allows us to estimate the time of surface impact for individual SSW events. We show that the surface impact following splitting events is, on average, about one week earlier than following displacement events, albeit with considerable variability. By compositing tropospheric responses around the identified date of surface impact, rather than around the central stratospheric onset date as common in previous studies, we can better constrain the surface signal of SSWs. We find that while the difference in North Atlantic Oscillation (NAO) anomalies between split and displacement vortices is small, surface temperature anomalies over northwest Europe and northern Eurasia are significantly colder for splitting events, particularly over the UK just prior to the surface impact date. Displacement events on average are wetter over Northwest Europe around the time of surface impact, consistent with the jet stream being displaced further south in response to split events. Our downtracking algorithm can be used with any reanalyses and gridded model data, and therefore will be a valuable tool for use with the latest climate models."
https://twitter.com/CorwinWright
SSWs come in two flavours, "splits" and "displacements", named based on what they do to the stratospheric wind patterns wind. Richard's algorithm lets him show that the surface impact following splitting events is about a week earlier than following displacement events on average
Overigens de opwarming gaat in verschillende fasen. Qver 15 dagen weer een flinke nieuwe impuls aan de al verwarmde stratosfeer.