A sudden stratospheric warming (SSW) is a rapid increase in temperature in the stratosphere, the layer of the Earth's atmosphere between the troposphere and the mesosphere. SSWs are typically associated with a weakening or reversal of the polar vortex, a large-scale circulation of air that surrounds the North and South Poles.
The most recent major SSW occurred in February 2018. This event had a significant impact on weather patterns across the Northern Hemisphere, including:
* A strong cold snap over North America and Europe. The SSW caused the polar vortex to split into two separate vortices, one of which moved over North America and Europe. This brought unusually cold temperatures to these regions, with some areas experiencing record-breaking lows.
* Heavy snowfall in the eastern United States. The cold air from the SSW combined with moisture from the Atlantic Ocean to produce heavy snowfall in the eastern United States. Some areas received more than a foot of snow, causing widespread travel disruptions.
* Disruption of the jet stream. The SSW disrupted the jet stream, a fast-moving current of air that flows from west to east in the upper atmosphere. This disruption caused the jet stream to split into two branches, one of which flowed south into the United States. This led to a change in weather patterns across the country, with some areas experiencing warm, dry weather while others experienced cold, wet weather.
The effects of the February 2018 SSW are still being studied, but it is clear that this event had a significant impact on weather patterns across the Northern Hemisphere.
Additional impacts of SSWs
In addition to the short-term weather impacts described above, SSWs can also have longer-term effects on climate. For example, SSWs have been linked to changes in the Arctic sea ice cover. SSWs can also affect the timing and strength of the Indian monsoon, which is crucial for water supplies and agriculture in South Asia.
SSWs are relatively rare events, but they can have a significant impact on weather and climate. Scientists are continuing to study SSWs to better understand their causes and effects and how best to predict them.
