Examkin

Question

Difficulty: HardClimate, Weather Systems, and Monsoon of India

Arrange the following atmospheric and meteorological developments associated with the upper atmospheric dynamic mechanism of the South-West Monsoon onset over India in their correct chronological sequence from earliest to latest:

  1. 1Intense solar heating of the Indian subcontinent and the Tibetan Plateau during spring.
  2. 2Abrupt northward displacement of the Subtropical Westerly Jet (STWJ) stream to the north of the Himalayas.
  3. 3Establishment of the Tropical Easterly Jet (TEJ) stream in the upper troposphere over Peninsular India.
  4. 4Sudden northward movement of the Inter-Tropical Convergence Zone (ITCZ) triggering the 'burst' of the monsoon over Kerala.

Answer

The correct chronological sequence of events leading to the South-West Monsoon onset is: 1. Intense solar heating of the Indian subcontinent and Tibetan Plateau → 2. Abrupt northward displacement of the Subtropical Westerly Jet stream north of the Himalayas → 3. Establishment of the Tropical Easterly Jet stream over Peninsular India → 4. Sudden northward movement of the ITCZ triggering the 'burst' of monsoon over Kerala.
The onset mechanism of the South-West monsoon involves a linked chain of thermal and dynamic events. First, intense seasonal solar heating warms the Indian subcontinent and Tibetan Plateau. This thermal engine forces the Subtropical Westerly Jet stream (STWJ) to abruptly jump north of the Himalayas. The resulting upper-air warm anticyclone over Tibet establishes the Tropical Easterly Jet (TEJ) over peninsular India. The strong upper-level divergence associated with the TEJ dynamically pulls the Inter-Tropical Convergence Zone (ITCZ) northward, drawing the moist south-west monsoon currents onto the Kerala coast to mark the official monsoon burst.

Step-by-Step Solution

1
Identify the foundational thermal trigger.
Solar radiation intense heating of the landmass and Tibetan Plateau establishes strong surface low pressure and thermal warming aloft in early summer.
Without surface differential heating and high plateau warming, the upper atmospheric pressure gradient cannot reverse.
2
Trace the upper-tropospheric jet stream relocation.
The Subtropical Westerly Jet (STWJ), which anchored south of the Himalayas through winter, breaks away and shifts abruptly north of Tibet in late May.
The physical barrier of the Himalayas retains the STWJ until warming over Tibet weakens the southern jet trough.
3
Identify the creation of upper-level easterly circulation.
With the STWJ removed, the high-altitude Tibetan warm anticyclone drives upper outflow southward, establishing the Tropical Easterly Jet (TEJ) across peninsular India.
The TEJ relies directly on upper-tropospheric outflow from the heated Tibetan plateau.
4
Determine the surface weather response and monsoon arrival.
Strong divergence aloft created by the TEJ draws the Inter-Tropical Convergence Zone (ITCZ) rapidly northward to ~20°N latitude, pulling moist maritime south-westerly trade winds into Kerala as the monsoon burst.
Upper atmospheric suction combined with surface thermal depression completes the dynamic coupling required for monsoon onset.

Key Concept

Dynamic and Upper Atmospheric Mechanism of South-West Monsoon Onset
Rate this question

Topics

Climate, Weather Systems, and Monsoon of India

More questions from this topic