Cyclone Gaja

• 15 Nov 2018

A deep depression in the bay of bengal has intensified into a cyclonic storm and is likely to hit the coasts of Tamil Nadu.

• There is long sea travel ahead for Gaja, along with that sea surface temperatures are also warm and low vertical wind shear.
• Besides this, Madden-Julian Oscillation (MJO) is also in the favourable zone. All these factors would be responsible in providing more strength to the system.
• The cyclone Gaja means elephant in Sanskrit language and has been named by Sri Lanka. It will be the second cyclone to hit the coastal area in a month after Cyclone Titli wreaked havoc in Odisha and Andhra Pradesh.

Madden-Julian Oscillation

• The Madden-Julian Oscillation is a major fluctuation in tropical circulation and rainfall that moves eastward along the equator, and circles the entire globe in a span of 30–60 days on an average.
• The MJO, therefore is not static and is a moving system of wind, cloud and pressure that brings rain as it circles around the equator.
• The phenomenon takes its name from the two scientists who identified it in 1971 — Roland Madden and Paul Julian.
• In the active phase, MJO results in more than average rainfall for that time of the year, while in the suppressed phase, the area receives less than average rainfall.
• The effect of the MJO is witnessed mainly in the tropical region, in the band between 30 degrees North and 30 degrees South of the equator, even though the mid-latitude regions in both hemispheres also feel its impact.