Question

For short-term climatic predictions, which one of the following events, detected in the last decade, is associated with occasional weak monsoon rains in the Indian subcontinent?
A. La Nina
B. Movement of jet streams
C. El Nino and southern oscillations
D. Greenhouse effect on global level

Answer 1

Hint: The short term climatic predictions are important for the seasonal prediction of the Indian summer monsoon rainfall. It is used for planning strategies towards the management of agricultural production and water resources.

Complete answer:
- Option A: La Nina is a weather pattern that occurs in the Pacific Ocean in which the strong winds blow warm water at the ocean's surface from South America to Indonesia resulting in the rise of cold water from the deep to the surface near the coast of South America as warm water moves west. Hence, this is an incorrect option.
- Option B: Movement of jet streams are from the west to east but the flow often shifts to the north and south. Jet streams are narrow bands of strong winds that are present in the upper level of the atmosphere. The earth’s rotation is the possible reason for jet streams. Hence, this is an incorrect option.
- Option C: El Nino and southern oscillations is an irregular periodic period that affects the climate of much of the tropics and subtropics. It is the variation in sea surface temperatures and winds over the tropical eastern Pacific Ocean. This was the event associated with occasional weak monsoon rains in the Indian subcontinent. Hence, this is the correct option.
- Option D: The greenhouse effect on the global level is increasing the temperature of the Earth as the carbon dioxide level is rising consistently and trapping heat inside the atmosphere. Hence, this is an incorrect option.

So, the correct answer is option C.

Note: Because of considerable research on the Indian Monsoon, it is established that the monsoon has limited potential predictability. The predictability of monsoon is also affected by the atmospheric climate around the world.