WEBVTT 1 00:00:00.060 --> 00:00:04.220 We plan our lives around rain. We always want to know when and 2 00:00:04.240 --> 00:00:08.400 where and how much. Not just for our weekend plans, 3 00:00:08.420 --> 00:00:12.590 but for how we make decisions about our safety and transportation, our economy, 4 00:00:12.610 --> 00:00:16.760 our livelihoods. So, how do we measure rain? 5 00:00:16.780 --> 00:00:20.950 Well, we can set out a rain gauge, like this one, and it measures the amount 6 00:00:20.970 --> 00:00:25.120 of rain that falls over time. The problem with this is that only measures rain in one 7 00:00:25.140 --> 00:00:29.310 very small spot. In fact, if you took all the rain gauges in the world 8 00:00:29.330 --> 00:00:33.500 packed them together, they would into two basketball courts. Now 9 00:00:33.520 --> 00:00:37.650 we can cover more ground if we use radar. Radar sends out a signal, 10 00:00:37.670 --> 00:00:41.790 and it measures how much of that signal is scattered by rain or snow. But radars 11 00:00:41.810 --> 00:00:45.920 are only available in certain parts of the world, and many countries just don't have access to 12 00:00:45.940 --> 00:00:50.020 that technology. And that's just on land. Think about 13 00:00:50.040 --> 00:00:54.120 how we're going to measure rain over all of the world's oceans. 14 00:00:54.140 --> 00:00:58.180 Look, the point is it's impossible to cover the entire Earth with enough instruments 15 00:00:58.200 --> 00:01:02.230 that are going to give us accurate precipitation rates for the whole globe. 16 00:01:02.250 --> 00:01:06.260 So, we have to think bigger and higher. Instead of having a 17 00:01:06.280 --> 00:01:10.430 patchy network of rain gauges and radars, we can have a whole constellation of satellites 18 00:01:10.450 --> 00:01:14.620 looking down at the Earth, measuring things like falling rain, 19 00:01:14.640 --> 00:01:18.800 snow and even ice. The Global Precipitation Measurement mission, or GPM, 20 00:01:18.820 --> 00:01:22.990 is going to do that. And it's going to give us precipitation rates for the whole 21 00:01:23.010 --> 00:01:27.020 globe every three hours. Now GPM is going to cover it all: 22 00:01:27.040 --> 00:01:31.190 from land and oceans, from the tropics to the edge of the poles, 23 00:01:31.210 --> 00:01:35.370 over mountains and valleys, from our 24 00:01:35.390 --> 00:01:39.510 farmland to our cities and towns. We're going to need 25 00:01:39.530 --> 00:01:43.650 more than a perspective on the ground if we're going to look at precipitation from a truly global 26 00:01:43.670 --> 00:01:47.770 standpoint, and GPM is just the mission that's going to give us that big picture. 27 00:01:47.790 --> 00:01:51.950 [music ends] 28 00:01:51.970 --> 00:01:56.040 [beeping sound] 29 00:01:56.060 --> 00:02:00.120 [beeping sound] 30 00:02:00.140 --> 00:02:01.168 [beeping sound]