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A Walk in the Clouds With a NASA Satellite
04.17.06
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Narrator: A walk in the clouds, with a NASA satellite. I'm Jane Platt, and you're listening to a podcast from JPL - NASA's Jet Propulsion Laboratory in Pasadena, California.

Clouds come in all sizes and shapes. They're part of the landscape of our daily lives. Before long, when NASA's CloudSat mission launches, we will know even more about clouds and how they affect our climate, our weather and our water supply. Joining us today is CloudSat Project Manager Tom Livermore of JPL. Welcome, Tom.

Livermore: Good morning, Jane, how are you?

Narrator: Good, thank you. A quick overview of what CloudSat's going to tell us about our clouds?

Livermore: CloudSat is a new space instrument that will be overflying the Earth, and the principal thing it's going to do for us is give us what we call a three-dimensional view of clouds. In other words, it's going to be able to tell us what's inside of clouds. We can look up and see where the clouds are. We can look down from space and see the tops of clouds. But there's nothing right now in space that regularly goes over and looks at what's in the clouds. How much water content is in the clouds, how much ice content is in the clouds, and makes those measurements for us so we can get a better understanding of how clouds interact, as you pointed out, with both the long-term climatic process as well as short-term weather forecasting.

Narrator: How will CloudSat do this? How will it study clouds?

Livermore: Oh well, thank you. CloudSat is actually a radar. We all know that there are a lot of radars around but this is a very special radar. For the first time in space, we're going to fly a radar that operates at a specific frequency that allows us to interact with the water droplets that form clouds. Now as you know, as water evaporates from the earth, it forms water vapor and we can't measure that, but as soon as a cloud is formed, and a cloud is formed by water droplets forming, that's what we all see as the cloud, then our radar can start detecting that and measure how much water and ice is inside that cloud. And so basically we send out a radar pulse and it gets bounced back and the information that comes back as it bounces back tells us the height of the cloud and how much water is in there.

Narrator: And why is it so important for us to know about that?

Livermore: The water that's inside the clouds is one of the variables that affects climatic models, for one thing, and it also affects very, very clearly, short term weather forecasting. Ya' know, there s a lot of discussion in the climate about whether or not as we get more water on Earth, more water will evaporate and form more clouds and whether that will cause the Earth to heat more or whether because there are more clouds, more sunlight will be reflected. And understanding how much water is in clouds is gonna help us determine that. And this is very critical to determining, as a matter of fact, whether in the long-term, the Earth will continue to heat, or whether as a matter of fact it will begin cooling down as more water comes and more clouds form.

Narrator: And CloudSat will be studying clouds globally, around the whole Earth.

Livermore: That's correct. As CloudSat orbits the earth, and it orbits the Earth approximately every 90 minutes, about every hour and a half, the Earth rotates under it, so we get a scan every hour-and-a-half of one strip around the Earth. And as the Earth rotates under it, we image the whole Earth.

Narrator: So you'll be able to monitor how the clouds are sort of moving in patterns around the globe?

Livermore: Exactly, exactly, and we can look at how the clouds move now, but what we don't know is how much water content is in those clouds, and also, as we measure that water content, we also can determine how much precipitates out as rain. And so we can look at how these weather patterns as they move around the globe, how that interacts with where rain's going to fall and where it's going to fall in the future.

Narrator: I don't think we've talked much, if at all, about the water supply and how CloudSat will, the implications of CloudSat on the water supply.

Livermore: That whole fresh water supply is continually recycled by clouds. Clouds is the only mechanism that recycles that. It takes the water that's in the ocean and recycles it back into the lakes, the rivers, the streams, and the aquifers in the world. Now, understanding that process and how that process is changing with the global heating and the other environmental changes is extremely important. Because we need to know in the future where we should grow our crops and where the water supply's going to be. And CloudSat is going to help us understand that. Very important to the man on the street obviously, because he's using this water, or she's using this water. And also very important to the farmer in the field.

Narrator: Is CloudSat going to send back pictures or data, or what will be able to see or find out?

Livermore: It will send back data and we will turn those data into pictures. Colorado state university, CERA, which is the organization that will be doing this for us, will take this data, and turn it into images, 3-dimensional images. And we'll be able to actually see, in fact, hopefully we'll be able to see this on our weather forecasts that come in the evening how much water is in these big storms as they come through. A new slice through the clouds, you'll be able to see a slice through the clouds that says look at this storm it's got all this water in it, and it's cold or it's warm, and it's going to create this huge storm, versus look at these clouds over here that don't have much water content and aren't very active.

Narrator: OK, quick wrapup, if you can just kind of give me some bullet points. After CloudSat launches, you think you will know more about what?

Livermore: We will know more about the internal structure of clouds and therefore we will be able to predict betterwhere, for instance, storms are going to track. We'll be able to predict better where the water resources are going to be in the future. We'll be able to predict better how intense storms are going to be. Those are key criteria that we'll be able to make a big improvement with CloudSat.

Narrator: Well thank you very much for joining us.

Livermore: Thank you, appreciate the time.

Narrator: We've been talking today with Tom Livermore of JPL. He is the CloudSat Project Manager. More information on the mission is online at www.nasa.gov/cloudsat . Thanks for listening to this podcast from NASA's Jet Propulsion Laboratory.