Data from TOPEX/Poseidon helps us study and understand the complex interactions between the oceans and the atmosphere which affect global weather and climate events. During an El Ni簽o event, the trade winds weaken and warm, nutrient-poor water occupies the entire tropical Pacific Ocean. Heavy rains that are tied to the warm water move into the central Pacific Ocean and cause drought in Indonesia and Australia. This also alters the path of the atmospheric jet stream over North and South America. El Ni簽os disrupt normal winter conditions throughout the Pacific Ocean. Reliable predictions of an El Ni簽o occurrence will lead to better preparation for its widespread impact. Warm El Ni簽os and cold La Ni簽as follow each other against the backdrop of the ocean seasons. During a La Ni簽a, the trade winds are stronger and cold, nutrient-rich water occupies much of the tropical Pacific Ocean. Most of the precipitation occurs in the western tropical Pacific Ocean, so rain is abundant over Indonesia.