Abstract:
The stratospheric polar vortex is a large ring of strong winds that forms high above the Arctic and Antarctic each winter. It develops because the polar atmosphere cools dramatically in the absence of sunlight, creating sharp temperature contrasts that drive fast-moving air around the pole. Although it forms in the stratosphere, the vortex is closely connected to weather systems below. Disturbances from the lower atmosphere can weaken or disrupt the vortex. In extreme cases, this leads to a sudden stratospheric warming (SSW), when temperatures over the pole rise rapidly and the usual wind pattern can slow down or even reverse. These events can reshape the circulation of the atmosphere for weeks. Importantly, changes in the polar vortex do not stay high above us. They can influence the jet stream and shift typical weather patterns, sometimes increasing the likelihood of cold spells or unusual conditions across parts of North America, Europe, and Asia. Understanding the polar vortex therefore helps us better anticipate periods of unusual winter weather and improve forecasts on weekly to seasonal timescales.
What is the Joint Oslo Seminar (JOS):
- Atmospheric and climate sciences have a stronghold in Oslo among the four institutions University of Oslo, the Meteorological Institute, CICERO and NILU.
- This joint seminar invites renowned international experts to contribute to an informal series of lectures, meant to create interaction with the Oslo atmospheric and climate science community on recent highlights and analysis in the field.
- Normally seminars will be held on Thursdays (12:15 pm -1pm).