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[chimes]

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My name's Bryan Blair, I'm an instrument scientist in the

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laser remote sensing laboratory at Goddard.

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LVIS is a high altitude, laser swath

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mapping system, so it's designed to measure the surface of the Earth.

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So whether it's the topography, the elevations,

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of the surface, or the structure of vegetation, or the

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changes that are happening to the surface, whether they're subtle changes

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for example, volcanic sources, underground magma chambers, or

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very dynamic surfaces like glaciers, for example,

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so it's a unique capability because we can map

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incredibly large areas from a high altitude aircraft

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so we can map actually, we are getting to the point where we can map

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an entire nation with a laser system, so it's quite good.

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For IceBridge,

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there was a number of goals of IceBridge.

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Namely, to keep track of what changes were happening

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to the ice sheets in between the two ICESat missions, ICESat one and ICESat-2,

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so we actually get out there on a yearly basis and monitor the

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changes. And then there was a more long-term goal,

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which would be to help tie those two satellite missions together.

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So in one aspect you'd be looking at individual

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glaciers and in the other you'd actually be trying to lay out large grid patterns

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all over Greenland so that you could look at the changes over

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ten or twenty years. And it would contribute to that. So what LVIS brings,

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uniquely, is the ability to cover enormous

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areas very cost effectively.

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What we've been doing so far with IceBridge is going back at a

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a stable time in the ice sheets. In the spring for example in Greenland we

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go in the March April May time period because the

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drastic changes, the seasonal melt, the accumulation

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from the winter have sort of stabilized, so we can go back once a year

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and look at those long term trends in those ice sheets.

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So what we're doing this fall, we're going to see a six-month

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change. And that six-month change is more related to those seasonal effects.

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The summer melt that's been occurring. So we can go in

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there and look at glaciers and some of the interior of the ice sheets

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and see how much melt has occurred.

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And with LVIS and all the spring mapping that we did we'll be able to look

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at that change over large areas.

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One of the really unique technologies about LVIS is

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there's some optical limitations to telescopes. So a telescope can only be

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so large, collect so much light, and see

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so big of an angular field of view. So with LVIS,

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we actually have a mechanical, a very unique lightweight scanning system

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that actually scans the field of view of the telescope as constantly as we're flying along,

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so it's actually sweeping back and forth about 10 or 20 times

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a second. And then within that field of view we're scanning our laser very

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quickly to make that full images. So it's a really, it's a unique

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technology that allows us to have a large telescope which you need to be able to

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collect all the photons and the reflected light from the surface, efficiently,

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so it's a large collecting area, with a large

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field of view.

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NASA Wallops Flight Facility has recently acquired a C-130

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aircraft. It's a large, turboprop aircraft.

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It can fly at 30,000 feet, it has pretty good endurance, so that what

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we're going to put LVIS on - the two LVISes on - this year.

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There's a lot of capacity of this aircraft. You could actually fly quite a number of instruments

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and we'll be the first to use it for NASA.

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[beep beep, beep beep]

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