El Niño and La Niña

Abstract El Nino and La Nina are the two complementary phase of the Southern Oscillation. During E1 Nina, the area of high sea surface temperatures increases, while the atmospheric convection zones of the tropical Pacific expand and merge so that there is a tendency toward spatially homogeneous conditions. La Nina is associated with low sea surface temperatures near the equator, with atmospheric convergence zones that are isolated from each other, and with spatial wales smaller than those of El Nina. It is proposed that both phases of the Southern Oscillation can be attributed to unstable interactions between the tropical ocean and atmosphere. During El Nina, the increase release of latent heat to the atmosphere drives the instability. During La Nina, when the heating of the atmosphere decreases, the compression of the convection into smaller and smaller areas permits an instability that intensifies the trade winds and the oceanic currents. The unstable air-sea interactions are modulated by the seasonal m...