Madden Julian Oscillation(MJO) : Meaning & Phases | MJO UPSC Notes

By BYJU'S Exam Prep

Updated on: September 20th, 2023

Madden-Julian Oscillation(MJO) is an oceanic, atmospheric phenomenon. MJO is the disturbance of wind, clouds, and pressure that moves in the east direction with speed equal to 4-8 m per second. Madden-Julian Oscillation is responsible for changes in weather activities all around the globe. The weekly and monthly fluctuations in the tropical weather are a result of the Madden-Julian Oscillation.

Madden-Julian Oscillation UPSC stands an important role in the Indian Climate and is a major topic for the IAS exam. Below you will get to know everything about the Madden-Julian Oscillation, Its phases, its importance, and how it affect the Indian weather.

What is Madden-Julian Oscillation(MJO)?

Madden-Julian Oscillation(MJO) is a geographical phenomenon that was discovered in the 1970s. MJO is responsible for the change in the weather all around the globe. Madden-Julian Oscillation is a traversing phenomenon and brings weekly and monthly weather changes in the tropical weather, most prominently over the Pacific Oceans and India.

  • It remains on the globe for an average of 30 to 60 days (sometimes it remains for 90 days).
  • The large cluster of clouds can range from 5000 to 10,000 Km in size and move towards the warm oceans from 60 65 degrees in the East to 150 180 degrees towards the East.

Madden-Julian Oscillation is responsible for creating cyclones. But, not all cyclones are born from the Madden-Julian Oscillation. Some of them might result from a simple Rossby wave.

The Madden-Julian Oscillation is created in the Indian Ocean and ends near the International Date Line, where the wave is moist, and this awareness leads to clouds all around.

Along with the most part, there is a dry part as well that comes back to its origin after moving all around the earth. This movement is called oscillation. The cycle keeps on repeating for 30 to 60 days. The Madden-Julian Oscillation is said to occur at a preferred time, especially in the winter season.

Madden-Julian Oscillation Latest News

A cyclone named Cyclone Asani was seen in the Bay of Bengal region. This cyclone became the reason for the rainfall on the Indian east coast. In the southern hemisphere, A twin Cyclone happened, and it was named Cyclone Karim. The major reason behind these twin cyclones is known to be caused Madden-Julian Oscillation.

Phases of Madden-Julian Oscillation

There are two phases of the Madden-Julian Oscillation. In the case of the strong Madden-Julian Oscillations, the earth gets divided into two non-equal halves, enhanced and suppressed phases. These are explained as

  • Enhanced rainfall (or convective) phase: In the enhanced rainfall phase, the wind gets converges at the surface, and the air is raised up in the atmosphere. In contrast to it this, the wind at the top is diverse. Because of this tension in the air motion, there is an increase in condensation and ultimately leading to rainfall. In this phase, there is more rainfall, cloudiness, and even storminess.
  • Suppressed rainfall (or suppressed) phase: In this phase, the wind at the top is converged because of which the air is forced to sink from the high altitudes. This makes the atmosphere dry and warms it as well, thus suppressing the rainfall. There is dryness and more sunshine in Suppressed rainfall.

Madden-Julian Oscillation and India Monsoon

The weather is impacted by MJO, EI Nino, and IOD (Indian Ocean Dipole). The MJO and EI Nino are responsible to affect the weather globally up to the mid-latitudes, while Indian Ocean Dipole is restricted to India only.

Madden-Julian Oscillation is a transverse phenomenon and is said to go through eight phases. MJO brings a good amount of rainfall over the Indian subcontinent when it is over the Indian Ocean during the Monsoon season. In contrast to this, when MJO remains on the Pacific Ocean with a longer cycle, there is a lack of rainfall in the Indian Monsoon.

Periodicity of MJO

The periodicity is nearly 30 days. After the completion of 30 days, MJO results in the Monsoon season with a good amount of rainfall. However, if it extends to 40 days, then there is a disturbance in the monsoon with low rainfall. Thus, the rainfall depends upon the MJO period. If MJO occurs for a shorter period, then there is good rainfall. Otherwise, it will lead to dry rainfall.

Madden-Julian Oscillation UPSC

Madden-Julian Oscillation UPSC comes under the Geography section of the UPSC Syllabus and holds an important section in the IAS Exam. Many questions have been asked in the UPSC Prelims and UPSC Mains exams. To ensure a better understanding of the topics, you can download the Geography Books for UPSC and other NCERT Books for UPSC. You can also refer to the UPSC Study Material.

Madden-Julian Oscillation UPSC Questions

Question: With reference to the Madden-Julian Oscillation (MJO), consider the following statements:

  1. Shorter the cycle of MJO, the better the Indian Monsoon.
  2. The active phase of MJO is responsible for the precipitation and formation of tropical cyclones.

Which of the statements given above is/are correct?

  1. 1 only
  2. 2 only
  3. Both 1 and 2
  4. Neither 1 nor 2

Answer: C. Both 1 and 2

Madden-Julian Oscillation UPSC Notes PDF

Madden-Julian Oscillation UPSC is a prime topic for the IAS exam, and various questions have been asked about this topic in the prelims and Mains exams. That’s why candidates need to cover this topic in detail. To help out the candidates, we have provided the Madden-Julian Oscillation notes in PDF format below.

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