Rossby waves
Also called: Planetary waves · Topic: Atmospheric Pressure, Winds and General Circulation · NCERT: Beyond NCERT
Meaning
Rossby waves are giant loops in the upper westerly winds and jet streams. They form because of the Earth's spin and because its turning effect changes with latitude. Usually four to six of them circle the globe. Normally they move along and carry weather systems with them. Sometimes they stall, which is called blocking. Then the same weather stays stuck over one place for days or weeks. This causes long heat waves, cold spells or floods.
Example
In 2010, a stalled Rossby wave pattern brought a long heat wave to Russia and severe floods to Pakistan at the same time. The 2021 heat dome over the Pacific Northwest of North America was also linked to a stalled wave.
Don't confuse with
- Jet stream: the fast core of wind itself. Rossby waves are the large bends and loops in that flow.
Related concepts
- Jet stream
- Polar front jet stream
- Subtropical westerly jet stream
- Tropical easterly jet stream
- Somali jet
- Polar vortex