According to researches how is a la Nina event triggered?

A La Niña event is typically triggered by a combination of cooler ocean temperatures in the central and eastern Pacific Ocean and changes in atmospheric conditions. These conditions can include strengthened trade winds that push warm surface waters toward the western Pacific, allowing colder, nutrient-rich waters to rise in the eastern Pacific. This shift in ocean temperatures disrupts normal weather patterns, often leading to increased rainfall in some regions and droughts in others. Overall, La Niña is part of the larger El Niño-Southern Oscillation (ENSO) climate phenomenon.