And after the surprise devastation of 1982-83, climate experts intensified efforts to understand how the process works globally. Completed in 1994, the TAO buoys are now the world's premier early-warning system for change in the tropical ocean. The data collected by the buoys are transmitted to polar-orbiting satellites and then to NOAA's Pacific Marine Environmental Laboratory in Seattle. Supplemented with temperature measurements taken by research ships, the data help create a comprehensive portrait of the upper ocean and lower atmosphere. Click to see entire image.
Weather is so variable that it's hard to call any situation normal.
But in most years climate in the equatorial Pacific is governed by one generally dependable pattern. Sunlight heats the uppermost layer of seawater in the western ocean around Australia and Indonesia, causing huge volumes of hot, moist air to rise thousands of feet and creating a low-pressure system at the ocean's surface. As the air mass rises and cools, it sheds its water content as rain, contributing to monsoons in the area. Now much drier and far aloft, the air heads east, guided by winds in the upper atmosphere, cooling even more and increasing in density as it travels. By the time it reaches the west coast of the Americas, it is cold and heavy enough that it starts to sink, creating a high-pressure system near the water's surface.