Dr. William Kessler:
We've known for more than 20 years that the Solomon Sea was likely to be an important player in El Niño. But we had no way to measure it. It's too remote. 

The study of the Solomon Sea waited until we had autonomous instruments that could be out there by themselves, measuring all the time. And the one we use is called the Spray glider. It's small, it's something that two people can pick up. The interesting thing about it is that it has no propeller, it has no jet, it has no forward propulsion at all. It starts out at the surface, it makes itself heavy. It starts to sink, it moves the batteries forward and the nose goes down. And then as it sinks, it slowly glides forward. Now, it does that down to a 1,000 meters depth. And it does the opposite, it makes itself light and points the nose up and as it rises it slowly glides forward. So, a dive like that covers about four kilometers and takes about four hours. 

Every time it comes to the surface, it finds its position by GPS. It makes a satellite call, sends off the data to us, asks for any instructions, goes back down. It can do that for 3,000 kilometers. So, we make two round trips across the Solomon Sea in one deployment. 

One of the strengths of a glider is that it moves slowly and it can be controlled through narrow passages and among the many reefs and islands. So, it's a difficult navigational task. It can come very close to shore so we know that we've really measured the total between the two coasts. And that would be difficult to do with a ship. 

The glider measures the temperature of the water, the salinity of the water, and the speed of the ocean currents. Even though the Solomon Sea is a small body of water, it carries a tremendous current. It's actually one of the great currents of the world ocean. The flow through the Solomon Sea is about 1,000 times as large as the Mississippi river in flood. This is really a tremendous source of water to the equator. So, by measuring the currents, and by measuring from one coast to the other coast, we know how much water is going through. 

We also want to know the temperature because we want to know how much heat is being pushed towards the equator by these currents. And, if that water is a little bit warmer than usual, or a little bit cooler than usual, that will affect how the next El Niño will form. 

El Niño distorts the whole atmospheric circulation. And in particular it affects where the winter rain and snow falls in the United States. That winter precipitation is a key source of water across much of the west. So, being able to predict how much water will fall during that winter lets a water manager, lets a farmer know how much can they use now? How much do they need to save? 

I'm a physical oceanographer, and I work on ocean circulation. I want to know how the instrument works, I want to have my hands on it, I want to get dirty in it and see how you actually make the measurements. 

PMEL is a federal government laboratory. What we can do is to engage in a long-term project and commit to it, and that's in some ways our role in the whole enterprise of science. We've been measuring there for now a little more than 10 years. We've seen two El Niño events, and we're just really beginning to be able to say, "What is the effect of the Solomon Sea on El Niño? How do those things interact?" If we can see lots warm water coming through the Solomon Sea, that's a hint that we're setting up for a strong El Niño. So it's that kind of value that being able to make a prediction of El Niño gives to the United States.