eXplainable AI to pridect the role of stratsphere-tropshere dynamical coupling in the unfolding of suface extreme events
The stratospheric circulation is characterized by three interacting features: the stratospheric polar vortex defined asthe wintertime westerly winds in the polar stratosphere, the Quasi-Biennial Oscillation (QBO) defined as anomalous tropicalzonal-mean zonal wind, and the overturning meridional circ...
| Main Authors: | , , , |
|---|---|
| Format: | Conference Object |
| Language: | English |
| Published: |
2023
|
| Subjects: | |
| Online Access: | https://juser.fz-juelich.de/record/1018685 https://juser.fz-juelich.de/search?p=id:%22FZJ-2023-04979%22 |
| Summary: | The stratospheric circulation is characterized by three interacting features: the stratospheric polar vortex defined asthe wintertime westerly winds in the polar stratosphere, the Quasi-Biennial Oscillation (QBO) defined as anomalous tropicalzonal-mean zonal wind, and the overturning meridional circulation known as the Brewer-Dobson Circulation (BDC; Baldwinet al. 2001, Kidston etval. 2015, Butchard, 2014). These three components are the main drivers of the stratospheric dynamicallinkages 5 between the tropics and high latitudes (Anstey & Shepherd, 2014) and also mediate the coupling between the stratosphereand the troposphere (Domeisen & Butler 2020). The strength of the stratospheric circulation, including the structure ofthe BDC, the phase of the QBO and the state of polar vortex, is driven by small-scale and large-scale wave breaking in thestratosphere and help setting the conditions for Arctic ozone-depletion induced by chemistry. These stratospheric conditions inturn modulate the occurrence of surface extreme weather events.10 In this presentation, I will summarise results of a study of how the stratosphere–troposphere dynamical coupling influencesthe circulation in the upper troposphere and lower stratosphere (UTLS) after a sudden stratospheric warming (SSW) during2005–2020 using the ERA5 reanalysis. In particular, I will then highlight the role of the stratosphere in predicting the 2018and 2019 precipitation and temperature exteme events over the Euro-mediterranean region using eXplainable Artificial NeuralNetwork approach. Finally, I will discuss the main reasons for the differences in the prediction accuracy between the 2018 and15 2019 impacts of stratospheric disturbances on the surface extreme events and the related dynamical processes associated withplanetary and gravity wave dissipation. |
|---|