"Typhoon Saudel Floods China's Coast as El Niño Intensifies Typhoon Season"
Typhoon
A tropical cyclone forming in the Western Pacific or South China Sea, equivalent to a hurricane or cyclone elsewhere.
El Niño
Periodic warming of central and eastern Pacific sea surface temperatures that disrupts normal atmospheric circulation patterns globally.
Tropical cyclones are intense rotating storm systems that form over warm tropical oceans. They are called typhoons in the Western Pacific and South China Sea, cyclones in the Indian Ocean, and hurricanes in the Atlantic. The Western Pacific basin is the most active cyclone basin on Earth, generating more tropical storms annually than any other region. China's southeastern coastal provinces, particularly Fujian, Guangdong, and Zhejiang, lie directly in the path of typhoons that form over the warm waters of the western Pacific and the South China Sea.
For a tropical cyclone to form, four key conditions must be met. Sea surface temperature (SST) must be at least 26–27°C to a depth of about 60 metres. There must be sufficient Coriolis force, which rules out formation within roughly 5° of the equator. Low vertical wind shear is needed so that wind speed and direction do not change sharply with altitude. Finally, there must be atmospheric instability and high humidity in the mid-troposphere. When these conditions align, a self-reinforcing system develops: warm ocean water evaporates, rises, condenses, releases latent heat, and draws in more surface air, spinning the storm faster.
The South Atlantic and southeastern Pacific remain largely cyclone-free because the Inter-Tropical Convergence Zone (ITCZ) seldom occurs there, denying storms the atmospheric trigger they need. This is a well-tested UPSC Prelims fact.
Typhoon tracks in the Western Pacific are steered by the Western Pacific subtropical high, a semi-permanent high-pressure belt. In normal years, this high sits at lower latitudes and deflects typhoons northward, away from China's coast. During an El Niño event, the subtropical high strengthens and shifts northward. This repositioning guides typhoons along a more direct northwest trajectory, increasing the frequency and intensity of landfalls on China's eastern and southeastern coast.
El Niño also shifts the zone of typhoon formation further east, into the central Pacific. Storms that form further east travel longer distances over open ocean before landfall. This extended ocean track allows them to intensify more, because they spend more time over warm water with low wind shear. The result is stronger storms at landfall, a pattern consistent with what experts observed during the Saudel season. …
In the South Atlantic and South-Eastern Pacific regions in tropical latitudes, cyclone does not originate. What is the reason?
Comment on the resource potentials of the long coastline of India and highlight the status of natural hazard preparedness in these areas.
Differentiate the causes of landslides in the Himalayan region and Western Ghats.
In the South Atlantic and South-Eastern Pacific regions in tropical latitudes, cyclones do not originate. The primary reason for this is:
1.Sea surface temperatures are consistently below the threshold for cyclone formation.
2.The Inter-Tropical Convergence Zone (ITCZ) seldom occurs in these regions.
3.The Coriolis force is too weak in these specific regions compared to other tropical basins.
4.These regions lack the low vertical wind shear necessary for cyclone development.
Which of the above is/are correct?
Consider the following statements regarding tropical cyclone formation:
1.Sea surface temperature must be at least 26–27°C to a depth of about 60 metres.
2.Tropical cyclones can form within 5° of the equator if sea surface temperatures are sufficiently high.
3.Low vertical wind shear is necessary for cyclone intensification.
4.The Western Pacific basin generates fewer tropical storms annually than the North Atlantic basin.
How many of the above statements are correct?
Consider the following statements about the effect of El Niño on typhoon activity in the Western Pacific:
1.El Niño causes the Western Pacific subtropical high to weaken and shift southward.
2.During El Niño, typhoon genesis shifts further east into the central Pacific, allowing storms to travel longer distances over warm water before landfall.
3.El Niño conditions can extend the Western Pacific typhoon season beyond the usual October–November end.
4.El Niño reduces the intensity of typhoons at landfall by increasing vertical wind shear over the western Pacific.
Which of the above statements is/are correct?
Match the following regional names for tropical cyclones with their respective ocean basins:
List I (Name) — List II (Ocean Basin)
A.Typhoon — 1. North Atlantic and Northeast Pacific
B.Hurricane — 2. Western Pacific and South China Sea
C.Cyclone — 3. North Indian Ocean and Southwest Pacific
D.Willy-Willy — 4. Western Australia
Consider the following pairs of secondary hazards associated with tropical cyclones and their primary mechanism:
1.Rainfall-induced landslides — Saturation of hill slopes reduces soil cohesion, triggering mass movement
2.Storm surge — Strong onshore winds push seawater inland, inundating coastal areas
3.Saltwater intrusion — Seawater flooding agricultural land reduces soil fertility
4.Flash floods — Rapid snowmelt triggered by cyclone winds in coastal plains
How many of the above pairs are correctly matched?
Want the full note, Prelims Facts & MCQ answers?
Create a free account — takes less than a minute.
Create free account