Which phenomenon describes the warming of surface waters in the central and eastern Pacific Ocean?

The phenomenon that describes the warming of surface waters in the central and eastern Pacific Ocean is El Niño. This climatic event is characterized by a significant increase in sea surface temperatures in this region, which can have far-reaching effects on global weather patterns.

El Niño occurs irregularly every few years and is usually associated with changes in atmospheric circulation. The warming of the ocean waters disrupts typical weather patterns, leading to various impacts such as increased rainfall in some areas, droughts in others, and changes in marine ecosystems. This phenomenon can significantly influence climate conditions not just locally, but also across continents, affecting agriculture, fisheries, and even storm activity.

In contrast, the other options provided describe different phenomena that do not involve the specific warming of surface waters in this region. For instance, La Niña refers to the cooling of ocean temperatures in the same area, while a monsoon is a seasonal wind pattern that brings significant rainfall, and an oceanic oscillation is a more general term referring to patterns of pressure and temperature variability in the ocean.