WEBVTT

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The GPM mission is a sophisticated network of satellites, covering the entire globe in less than three hours,

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giving us an unprecedented picture of precipitation, from rain to falling snow, hurricanes to monsoons,

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droughts and floods. So how do we get all of that information out of this? The short answer: Tons of data

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from all over.

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As GPM takes snapshots at precipitation, like in a major storm, the data gathered is transmitted

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to a network of satellites called TDRSS.

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Erich Stocker: The important thing to recognize is that the GPM satellite does not

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talk directly to the Earth; it talks to the communications satellite which is known as TDRSS. And the TDRSS satellites

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talk to a ground station, which is at White Sands, New Mexico, and that's a very effective way to get

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continuous data, which cannot be gotten otherwise, unless you do direct broadcast and have many, many ground stations, which isn't

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as effective as going through the TDRSS system.

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The White Sands Ground Station then sends information about the health and

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geolocation of the GPM Core satellite to the hub of all of this activity, the Missions Operations Center, located at NASA's

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Goddard Space Flight Center. The raw data streams into Goddard's Precipitation Processing System, or PPS.

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The data from the radar is routed through GPM's partner, the Japan Aerospace Exploration Agency, for initial processing

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and then is sent back to the PPS. George Huffman: The data that come down from

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the satellite are actually not precipitation. They're in the form of radiances,

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in the case of the microwave instruments, or reflectivities, in the case

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of the radar. The computer codes I've been talking about--the algorithms-- are the way we get from numbers

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that nobody including me can directly interpret to the thing we care about,

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which is precipitation. The GPM mission is not just the Core spacecraft, but also a constellation of existing satellites

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from partners around the world. Each constellation member may have its own

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unique scientific objectives, but they all contribute data to the PPS in order to develop global precipitation products.

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Erich Stocker: The Precipitation Processing System gets data from the satellite and various other sources and creates the science products

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that are going to be used for both applications purposes, that is societal benefits, and scientific research. The PPS then produces

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a suite of data products, including both instrument specific and merged data, unifying the data gathered by the international

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partner satellites that make up the GPM constellation.

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George Huffman: You could compare this to making soup. We have carrots, and we have onions, and we have potatoes.

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They're all vegetables. And so you have to wash them, peel them,

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take out the bad spots. That's a really important step, you don't want your soup to

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taste bad. When you get done, of course, you have to taste test it to make sure the

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seasoning right, and then you have to serve it. And so each of those steps

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in a mathematical sense, is what we have to do in order to take all the

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diverse sources of information and end up with a unified product which the user finds to be useful. These precipitation

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products will be useful in many societal applications, like hydrologic modeling, mapping potential natural disasters, agricultural modeling, weather prediction,

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and climate research. Erich Stocker: As we improve the precipitation retrievals that form the basis for these merged products

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that will get better and better, and we'll be seeing actual satellite data rather than just forecasts.