How is la Nina formed?

Answer 1

La Nina can only form after an El Niño. During an El Niño, types of waves, not beach waves, but massive movements of energy through water, are formed. They are Kelvin waves and Rossby waves. As Kelvin waves are formed, they push cold water down, which initially causes the ocean to warm. At the same time, another series of waves, Rossby waves, also form under water. They roll towards Asia and Australia. When the waves hit the coast, they reverse and head back towards South America. As the Rossby waves return, they leave cold water closer to the surface. If they bring back just enough cold water, the ocean temperatures return to normal, but sometimes they bring back to much, causing a La Niña after an El Niño.

Answer 2

La Niña is formed when sea surface temperatures in the central and eastern tropical Pacific Ocean become cooler than normal. This cooling occurs due to changes in atmospheric circulation patterns, which in turn lead to increased upwelling of cold, nutrient-rich waters in the region. La Niña events can impact global weather patterns by affecting precipitation and temperature patterns around the world.