Enso impacts to sensible weather are typically most pronounced from late fall through mid spring. Water near the equator warms up to a higher temperature, which causes the. C for the oceanic nino index oni 3 month running mean of ersst. Knowledge of ensos predictability and known impacts can benefit agriculture. 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. Oscillation, a seesaw in surface atmospheric pressure between the australianeast asian region and the eastern tropical. For climate scientists, this is a grey area as to whether. This needs to be recognized for scientific uses, and precision can only be achieved if the. They occur when the pacific ocean and the atmosphere above it change from their neutral normal state for several seasons.