LA NINA

Subject: Geography

Context: A cold wave in Delhi brought the night-time or minimum temperature down to 4.1 degrees Celsius, the lowest for the season so far this year, as per the IMD.

Concept:

• There has been significant snowfall in Western Himalayan region states and cold winds blowing from this area towards Delhi is causing temperatures to dip.
• States like Himachal Pradesh recorded snowfall over the last few days under the influence of a Western Disturbance, which also brought light showers to Delhi.
• After the passing of this Western Disturbance, the cloud cover cleared, resulting in higher radiation at night time, which also caused temperatures to dip.
• Also , La Niña climate pattern, which is currently active, is also resulting in lower temperatures across the globe.

La-Nina

• It means the large-scale cooling of ocean surface temperatures in the central and eastern equatorial Pacific Ocean, together with changes in the tropical atmospheric circulation, namely winds, pressure and rainfall.
• It has the opposite impacts on weather and climate as El Niño, which is the warm phase of the El Niño Southern Oscillation (ENSO).

Weather changes because of La Nina:

• The Horn of Africa and central Asia will see below average rainfall due to La Niña.
• East Africa is forecast to see drier-than-usual conditions, which together with the existing impacts of the desert locust invasion, may add to regional food insecurity.
• It could also lead to increased rainfall in southern Africa.
• It could also affect the South West Indian Ocean Tropical Cyclone season, reducing the intensity.
• Southeast Asia, some Pacific Islands and the northern region of South America are expected to receive above-average rainfall.
• In India, La Niña means the country will receive more rainfall than normal, leading to floods.