WEBVTT FILE

1
00:00:00.000 --> 00:00:03.990
[rain drops]

2
00:00:04.010 --> 00:00:08.040
[natural sound]

3
00:00:08.060 --> 00:00:12.230
[wind, rain]

4
00:00:12.250 --> 00:00:16.370
[water flowing]

5
00:00:16.390 --> 00:00:20.420
[water flowing]

6
00:00:20.440 --> 00:00:24.440
Dalia: Freshwater is extremely important on Earth. Only three

7
00:00:24.460 --> 00:00:28.480
percent of our water is actually in the form of freshwater.

8
00:00:28.500 --> 00:00:32.540
And only a fraction of that is actually usable

9
00:00:32.560 --> 00:00:36.580
freshwater on the surface.
Gail: If we don't know what

10
00:00:36.600 --> 00:00:40.620
kind of freshwater availability we have, then we may

11
00:00:40.640 --> 00:00:44.730
have issues in terms of droughts, we might have landslides,

12
00:00:44.750 --> 00:00:48.730
floods and things like that, and we need to be able to track those

13
00:00:48.750 --> 00:00:52.780
long term.
Dalia: Understanding how freshwater moves

14
00:00:52.800 --> 00:00:56.850
through the system is extremely important, both at the local scale, looking at how much water

15
00:00:56.870 --> 00:01:00.970
we have in our reservoir, to the larger scale, looking at how precipitation

16
00:01:00.990 --> 00:01:05.000
moves from ice pack, to the ocean, and then is

17
00:01:05.020 --> 00:01:09.040
evaporated from there. Sensors

18
00:01:09.060 --> 00:01:13.130
on the ground can look at a point source, so we understand how much rain is

19
00:01:13.150 --> 00:01:17.190
falling at a specific location, but there aren't very many

20
00:01:17.210 --> 00:01:21.210
gauges around the world that can provide that information for us.

21
00:01:21.230 --> 00:01:25.240
Arthur: If we were to take all the existing rain gauges in the

22
00:01:25.260 --> 00:01:29.280
world, they would fit into an area about the size of two

23
00:01:29.300 --> 00:01:33.320
basketball courts.
[rocket launching]

24
00:01:33.340 --> 00:01:37.340
[rocket launching]

25
00:01:37.360 --> 00:01:41.370
Dalia: So what satellites enable us to do is provide a much more global picture

26
00:01:41.390 --> 00:01:45.450
of the rain that we observe.
Arthur: GPM is an

27
00:01:45.470 --> 00:01:49.500
international satellite mission that will set a new standard for precipitation measurement

28
00:01:49.520 --> 00:01:53.570
from space, providing a new generation of observations

29
00:01:53.590 --> 00:01:57.620
of rain and snow in all parts of the world, every three hours.

30
00:01:57.640 --> 00:02:01.690
The GPM mission consists of a

31
00:02:01.710 --> 00:02:05.710
constellation of nine satellites, provided by a consortium of partners

32
00:02:05.730 --> 00:02:09.750
in the United States, Japan, France, India, and

33
00:02:09.770 --> 00:02:13.810
Europe. The GPM Constellation is

34
00:02:13.830 --> 00:02:17.860
united by a common reference satellite, known as the

35
00:02:17.880 --> 00:02:21.900
GPM Core Observatory, provided by NASA and JAXA.

36
00:02:21.920 --> 00:02:25.980
Candace: GPM is one of the largest spacecraft

37
00:02:26.000 --> 00:02:30.030
we've ever built here at Goddard. It's about 13 meters by

38
00:02:30.050 --> 00:02:34.060
6.5 meters by 5 meters. That's about the wingspan--

39
00:02:34.080 --> 00:02:38.120
tip to tip--of a small corporate jet, but only one-

40
00:02:38.140 --> 00:02:42.240
third as long. In the particular case of

41
00:02:42.260 --> 00:02:46.260
GPM, we're a follow-on mission to the Tropical Rainfall

42
00:02:46.280 --> 00:02:50.330
Measuring Mission which was launched in 1997. So part of what GPM

43
00:02:50.350 --> 00:02:54.410
was supposed to do was just continue those measurements, but also

44
00:02:54.430 --> 00:02:58.450
GPM is to improve those measurements by being able to, for example,

45
00:02:58.470 --> 00:03:02.490
measure finer precipitation.

46
00:03:02.510 --> 00:03:06.520
Art: The more channels you have within one instrument,

47
00:03:06.540 --> 00:03:10.590
then you can cover a wide spectrum

48
00:03:10.610 --> 00:03:14.750
of precipitation products. All the way from rain

49
00:03:14.770 --> 00:03:18.800
to ice.
Gail: The GPM Core has

50
00:03:18.820 --> 00:03:22.830
an active radar and a passive radiometer, and these two

51
00:03:22.850 --> 00:03:26.860
instruments are just like what a doctor might use, in terms of an X-ray

52
00:03:26.880 --> 00:03:30.910
for the radiometer, and a CAT scan

53
00:03:30.930 --> 00:03:34.960
for the radar to diagnose what's happening in clouds and to understand what's

54
00:03:34.980 --> 00:03:39.040
happening with the precipitation.
Arthur: The data collected by the GPM Core

55
00:03:39.060 --> 00:03:43.130
Observatory will provide a unique data set that will allow

56
00:03:43.150 --> 00:03:47.240
us to translate satellite measurements into the rain or snow

57
00:03:47.260 --> 00:03:51.260
that hits the ground, anywhere on the globe.

58
00:03:51.280 --> 00:03:55.310
[rain drops]

59
00:03:55.330 --> 00:03:59.350
[rain drops]

60
00:03:59.370 --> 00:04:06.627