Madden Julian Oscillation: MJO Full Form, Features, Phases UPSC Notes

The Madden Julian Oscillation (MJO) is a large-scale mutualistic coupling between atmospheric circulation and tropical deep convection characterised to occur as an eastward-traveling disturbance of cloud amount, rainfall, winds and pressure near the equatorial region that extends over an entire globe. Unlike other patterns of climate like El Niño or the Indian Ocean Dipole, which seem to remain at one place, this MJO moves eastward around the equator at 4 to 8 m/s, in a complete cycle that might take between 30 to 60 days. The Madden Julian Oscillation is critical to understand due to its effects on weather and climate patterns within the tropics and extratropics, including such phenomena as distant weather anomalies and monsoons.

The Madden Julian Oscillation upsc is a topic relevant in the context of the UPSC Civil Services Examination under General Studies Paper I, under the subject Geography. It is a basic topic for aspirants who help explain the dynamic behavior of atmospheric systems and, therefore, the far-reaching influences on global weather patterns, critical in climatology, meteorology, and seasonal variations that bear impacts on agriculture and, more importantly, disaster management.

What is Madden Julian Oscillation?

Madden Julian Oscillation (MJO) is an intra-seasonal variability in the tropics and describes a pattern of increased and suppressed rainfall. It is a traveling pattern that propagates eastward at speeds of 4 to 8 meters per second across the Indian and Pacific Oceans. This oscillation affects tropical weather, with periods of heightened convective activity and rainfall, followed by periods of suppressed convection. The MJO can be characterized by its periodicity of oscillation, normally completing the cycle of maximum and minimum convective activity within a period of 30 to 60 days. It extends well beyond the tropics in its influence over global atmospheric circulation and weather systems.

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Features of Madden Julian Oscillation

The Madden Julian Oscillation has some of the following characteristics:

• Propagation: The MJO propagates eastward along the equator, over mostly the Indian Ocean and the western Pacific Ocean at an average speed of between 4 to 8 meters per second.
• Convective and Suppressed Phases: It has two alternating phases in which the oscillation manifests enhanced and suppressed convective activity. Enhanced convection brings more cloudiness and heavier precipitation, whereas the suppressed phase is one in which there is decreased formation of clouds and, thus, reduced rainfall.
• Global Impact: Though the MJO is more pronounced over the tropics, its impact reaches the higher latitudes and regulates weather systems all around the globe. For example, it can regulate Indian Ocean cyclones and extreme weather over the mid-latitudes by modulating the activity of their cyclones.
• Periodic Nature: The MJO is periodic and has a periodicity between 30 and 60 days, with regular fluctuations of enhanced and suppressed convection.
• Interactions with Other Climate Phenomena: The MJO interacts with and modifies other climate phenomena, including the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD).
• Atmospheric Dynamics: It is characterized by complex interactions between large-scale atmospheric circulation, sea surface temperatures (SSTs), wind patterns, and convection.

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The Madden Julian Oscillation has two main phases:

Enhanced Convective Phase

The enhanced movement of air upwards is accompanied by increased cloudiness and heavy rainfall in this phase. Significant weather disturbances such as storms and monsoons characterize this phase. Such disturbances have a marked influence on the precipitation patterns and climate anomalies of regions affected by this phase. There is a westerly wind burst in the lower troposphere and an easterly wind anomaly in the upper troposphere during this phase.

Suppressed Convective Phase

This phase has low cloudiness and rainfall as downward air motions prevail. It tends to stabilize the weather, reducing the chances of convective storms and heavy precipitation. The suppressed phase observes easterly anomalies in the lower troposphere and westerly anomalies in the upper troposphere.

This periodic alternation of these phases leads to the oscillatory pattern in the MJO that has a great influence over the tropical weather and climate systems.

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Madden Julian Oscillation Effect on Indian Monsoon

The Madden Julian Oscillation has a profound effect on Indian monsoon, being one of the key drivers of intra-seasonal variability. The role of MJO in affecting the monsoon is a complex and multi-faceted phenomenon:

• Monsoon Onset and Withdrawal: When the enhanced convective phase of MJO is over the Indian Ocean, it helps initiate the onset of monsoon as it facilitates the necessary convective activity and moisture transport for the onset of the monsoon rains. Conversely, the presence of suppressed phase can delay the onset and also affects the withdrawal of monsoon.
• Rainfall Patterns: The MJO affects the distribution and intensity of rainfall in monsoons. In the strengthened phase, rainfall tends to be higher over the Indian subcontinent, leading to bursts in monsoon activity. During the suppressed phase, there is a decrease in rainfall and a break in monsoon activity.
• Monsoon Variability: Monsoon variability arises through fluctuation due to MJO's 30- to 60-day cycle; there are wet and dry phases during the monsoon season that thus drive intra-seasonal variability crucial for agricultural planning and water resource management.
• Tropical Cyclone Genesis: The intensified convective part of the MJO favors the probability of cyclogenesis in the Indian Ocean and, thus, may indirectly influence the formation of some tropical cyclones that strike along the Indian coast.

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Periodicity of Madden Julian Oscillation

The periodicity of the Madden Julian Oscillation is one of the characteristic features, which runs in the range of 30 to 60 days. This periodicity is controlled by the oscillatory nature of the convective and suppressed phases and the interplay of atmospheric and oceanic conditions. The variability of its cycle duration can be due to several factors.

• Ocean-Atmosphere Interactions: Interactions between sea surface temperatures and atmospheric dynamics can reduce or increase the MJO cycle. For example, warmer SSTs may intensify convective activity and therefore shorten the phase duration.
• Background State: The background state of the atmosphere, in addition to the presence of other climatic phenomena, such as ENSO, can also modulate the periodicity of the MJO.
• Longitudinal Position: The longitude along which the MJO is traveling can also be seen to affect its speed and periodicity. For example, the oscillation might move more slowly over the warm waters of the western Pacific compared with the cooler central Pacific or Indian Ocean.

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Significance of Madden Julian Oscillation (MJO)

Madden Julian Oscillation plays an important role in the global weather and climate systems with many significant impacts:

• Better Forecasts: The incorporation of MJO into the weather models enables meteorologists to better forecast the medium- to long-term weather conditions, particularly for the tropical regions and monsoon predictions.
• Cyclone Predictions: The phases of MJO can predict the development and track of the tropical cyclones that can aid disaster preparedness and response efforts.
• Global Climate Patterns: The MJO influences global atmospheric circulation, affecting climate patterns beyond the tropics, including the jet stream and mid-latitude weather systems.
• ENSO Interaction: The interaction between the MJO and ENSO can significantly impact global climate anomalies, influencing droughts, floods, and temperature extremes.
• Monsoon Management: Its understanding within the Indian subcontinent allows for agricultural planning given that timing and distribution significantly affect rains during the onset of a monsoon-the critical sources of crop and water productions.
• Drought and Flood Mitigation: Droughts and floods can be mitigated for farmers once they predict the high or suppressed rainfall periods better.
• Energy Sector: MJO influences global energy, influencing weather conditions that modify demand and production for heating, cooling, and renewables.
• Insurance and Risk Management: It helps with improved risk assessment for better management for the insurance and reinsurance industry through predictive techniques for extreme weather associated with the MJO phenomenon.

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