The correct option is Recurve and become more destructive.
Explanation
Tropical cyclones originate in the tropical oceans and are initially steered by the prevailing winds of the region, specifically the Trade Winds (Easterlies). Their movement and trajectory are influenced by atmospheric pressure belts, the Coriolis force, and upper-level winds.Detailed
- Initial Movement (0°-20° Latitude): Tropical cyclones typically move from east to west (or northwest in the Northern Hemisphere) under the influence of the Trade Winds.
- Recurvature (Crossing 20° N): As these cyclones cross the 20° N latitude, they move out of the influence of the Trade Winds and into the zone of the Westerlies and the subtropical high-pressure belt.
- The Coriolis force, which increases with latitude, causes the cyclone to deflect to the right in the Northern Hemisphere.
- Consequently, the cyclone changes its path from a westward direction to a northward and then north-eastward direction. This phenomenon is known as recurvature.
- Destructive Potential: Recurving cyclones are often considered more destructive because:
- They tend to accelerate in forward speed after recurving.
- Their path becomes more erratic and difficult to forecast compared to the steady westward track.
- They may interact with mid-latitude weather systems, expanding their size and impact area, even if their core wind speeds slightly decrease due to cooler waters.
- Incorrect Options:
- Dissipate immediately. Dissipate immediately: Cyclones do not dissipate solely by crossing a latitude; they dissipate when cut off from moisture (landfall) or when moving over significantly colder waters.
- Move back towards the equator. Move back towards the equator: The Coriolis force pulls systems poleward, preventing movement back toward the equator.
- Turn into extra tropical cyclones. Turn into extra-tropical cyclones: While this transition eventually happens, it typically occurs at higher latitudes (30°-40° N) as the system encounters frontal zones, not immediately upon crossing 20° N.
Key Takeaway:
Tropical cyclones generally move westward in the tropics (Trade Winds) but recurve towards the northeast upon crossing approximately 20° N latitude due to the influence of the Westerlies and the Coriolis force.