Armada begins study of Western Pacific.

Hundreds of scientists from 19 nations will embark next week on a mammoth study designed to investigate how the western Pacific Ocean plays a fundamental role in Earth's climate. The four-month effort, based out of northeast Australia, will involve seven satellites, seven aircraft, 14 ships, 34 instrumented buoys, and 37 weather stations.

Called the Coupled Ocean-Atmosphere Response Experiment, the project will probe the atmosphere and ocean in the vicinity of a huge pool of warm water that straddles the equator. Water temperatures in the pool prompt tremendous amounts of evaporation and rainfall that stir the equatorial atmosphere. During an El Nino warming, such as happened last year, the pool shifts far to the east, causing major disruptions in the weather around much of the globe. El Nino warmings recur erratically every four to seven years. Between these events, the warm pool sometimes shifts far back to the west, spurring another weather-altering phenomenon known as La Nina cooling -- a feature that currently may be developing.

By investigating the warm pool, researchers hope to gather data that will improve computer models used in forecasting how Earth's climate will evolve in the future.