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