In the South Atlantic and South-Eastern Pacific regions in tropical latitudes, cyclone does not originate. What is the reason?
[UPSC Civil Services Exam – 2015 Prelims]
(a) Sea surface temperatures are low
(b) Inter-Tropical Convergence Zone seldom occurs
(c) Coriolis force is too weak
(d) Absence of land in those regions
Answer: (b)
Explanation:
The South Atlantic is not conducive to the formation of cyclones due to several reasons:
- The sea surface temperatures are slightly cooler than the optimum temperature required for tropical cyclone formation.
- The area experiences high vertical wind shear throughout the year, which further inhibits cyclone formation.
- Additionally, there is a lack of pre-existing centers of rotation and tropical waves in the region, which also contributes to the absence of cyclones.
- The Intertropical Convergence Zone (ITCZ) remains at or north of the equator, resulting in a lack of synoptic vorticity and convergence necessary for cyclone formation.
- Furthermore, the strong wind shear and absence of ITCZ over the ocean make it challenging to generate tropical cyclones.
- The South Atlantic and South Pacific regions also lack the ITCZ over them, which is a crucial factor contributing to the lack of cyclones.
- Finally, the lower sea temperatures in the region also play a role in the absence of cyclone formation.
Therefore, option (b) is the correct answer.
