New Mexico Institute of Mining & Technology, Adjunct Professor of Physics
April 18, 2022
Email office@phys.ksu.edu for the Zoom address
Dramatic headlines in recent years declare “the polar vortex is coming” and blame extreme weather events such as cold air outbreaks on “polar vortex events”, or even refer to such weather events as “polar vortex outbreaks”. In scientific usage, the stratospheric polar vortex is a climatological feature dominating the atmospheric circulation from about 15 to 50 km altitude that forms every fall and breaks down every spring. The tropospheric (from the surface to the tropopause at about 10–15 km altitude) circulation is more aptly describe by complex regionally-varying patterns of strong localized (in horizontal and vertical) winds called jet streams that have maximum speeds in the upper troposphere (near 8–12 km altitude). Much research has elucidated links of anomalies in the stratospheric polar vortex to extreme weather events at the Earth’s surface. In particular, cold air outbreaks in some regions of the Northern Hemisphere are more likely to occur and more likely to be severe following dramatic mid-winter disruptions of the stratospheric polar vortex known as sudden stratospheric warmings. Conversely, extremely strong stratospheric polar vortex states have been linked to extreme regional heat events. The role of the jet streams in the link between stratospheric polar vortex anomalies and extreme surface weather events has not yet been studied in detail. In this talk, I will define and describe the stratospheric polar vortex and tropospheric jet streams and their dynamical origins; show some examples of recent extreme events that have been related to stratospheric polar vortex anomalies; and finally present some initial work exploring the role of the jet streams in the relationship between the stratosphere and extreme surface weather events.
