Why in the News
Two recent studies published in Weather and Climate Dynamics and presented at the American Meteorological Society meeting explain why wildfire smoke in the stratosphere forms spinning bubbles that rotate in only one direction depending on the hemisphere.
What Is Observed?
- After intense wildfires, smoke can rise high into the stratosphere. Instead of dispersing immediately, it sometimes forms a compact spinning bubble called a smoke vortex.
- Clockwise in the Northern Hemisphere
- Counterclockwise in the Southern Hemisphere
Why Does It Rotate Only One Way?
- Smoke Heats the Surrounding Air: Smoke particles absorb sunlight. This warms the air around them. Warm air becomes buoyant and rises. This upward movement creates a vertical column of heated air.
- Earth’s Rotation Effect: Because Earth rotates, moving air experiences a deflection known as the Coriolis effect.
- In the Northern Hemisphere, air is deflected to the right. In the Southern Hemisphere, air is deflected to the left. As the heated smoke rises, Earth’s rotation causes it to spin in a preferred direction.
Why the Bubble Persists
- The rotating vortex traps warm smoke near its centre. Reduces mixing with surrounding air.
- Helps the bubble rise higher into the stratosphere. This mechanism is similar to how cyclones maintain structure, but on a smaller and smoke driven scale.
| [2024] With reference to “Coriolis force,” which of the following statements is/are correct?
1. It increases with increase in wind velocity. 2. It is maximum at the poles and is absent at the equator. Select the answer using the code given below: (a) 1 only (b) 2 only (c) Both 1 and 2 (d) Neither 1 nor 2 |
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