El – Nino is a narrow warm, current which occurs on the coast of Peru in December. It is given the name ‘Christ Child’ due to its development near Christmas. The El – Nino phenomena which influences the Indian monsoon reveals that when the surface temperature goes up in the Southern Pacific Ocean, India receives deficient rainfall, and conversely, India receives sufficient rainfall during La-Nina.
The temperature in the South Pacific Ocean increases or decreases by 2°C or 4°C, this is known as El-Nino and La – Nina respectively.
1. El – Nino Effect and Monsoon: The condition of atmospheric pressure is affected by the rise in temperature in the South Pacific Ocean near the coast of Peru. Due to the rise in temperature, the atmospheric pressure in this region reduces. It is assumed that this affects the global atmospheric pressure system and air flow system. With lower atmospheric pressure condition near the coast of Peru, the force that pushes out the Soxith – eastern trade winds becomes weaker and hence the force attracting the trade winds gets activated. Due to this reason, the flow of these winds towards Asia becomes weak. This gives rise to the possibility of delayed and weak Summer Monsoon. This nature of El-Nino is being presented in the following map:
2. La – Nina Effect and Monsoon: When the temperature reduces in the South Pacific Ocean near the coast of Peru, then higher atmospheric pressure is developed. Due to this reason, the Iprce that pushes out the south-eastern trade winds becomes stronger and hence the force attracting the trade winds gets deactivated. Due to this trend possibility is expressed of an early arrival of active monsoon in India. This nature of La – Nina is being presented in the following map:
