WEBVTT - TechStuff Classic: Weather Tech, Part 2 0:00:04.360 --> 0:00:12.360 Welcome to tech Stuff, a production from iHeartRadio. Hey there, 0:00:12.440 --> 0:00:16.160 and welcome to tech Stuff. I'm your host, Jonathan Strickland. 0:00:16.200 --> 0:00:19.599 I'm an executive producer with iHeartRadio and how the tech 0:00:19.640 --> 0:00:22.880 are you. It's Friday, so it's time for another classic episode. 0:00:23.120 --> 0:00:26.440 This is the second part of a two parter called 0:00:26.720 --> 0:00:30.360 weather Tech Part two. So if you didn't listen to 0:00:30.480 --> 0:00:33.280 last week's classic episode of weather Tech Part one, I 0:00:33.320 --> 0:00:35.400 recommend you do that. That would have been last Friday. 0:00:36.080 --> 0:00:41.920 This episode originally published on April twenty first, two sixteen. Enjoy. 0:00:42.960 --> 0:00:46.560 We are now going to join the podcast already in progress. 0:00:48.440 --> 0:00:51.360 We were able to gather a lot of information once 0:00:51.440 --> 0:00:55.000 we had those basic tools available to us. But what 0:00:55.280 --> 0:01:00.560 really pushed meteorology forward is when we could stop relying 0:01:00.640 --> 0:01:03.240 upon the data that we can gather here on the 0:01:03.280 --> 0:01:08.320 ground and supplement that with information from the atmosphere itself. 0:01:08.880 --> 0:01:12.679 And that brings us to weather balloons. Weather balloons more 0:01:12.720 --> 0:01:17.640 than just fodder for your roswell conspiracy right right, Swamp 0:01:17.680 --> 0:01:21.319 gas and weather balloons and weather balloons do more than 0:01:21.400 --> 0:01:25.039 just act as a subplot in an X Files episode. Right, Yes, 0:01:25.080 --> 0:01:29.560 They're very important. Yeah, so they carry instrumentation that collects 0:01:29.640 --> 0:01:35.120 data about atmospheric conditions and weather balloons have been around 0:01:35.120 --> 0:01:39.280 for a long time, but more recently they typically carry 0:01:39.319 --> 0:01:43.160 instruments called radiosond, which is a battery powered device that 0:01:43.160 --> 0:01:47.840 can measure altitude, atmospheric pressure, temperature, humidity, wind speed. Sometimes 0:01:47.840 --> 0:01:51.280 there's a GPS element to it, so it can so 0:01:51.400 --> 0:01:53.440 people on the ground can track where the weather balloon is. 0:01:53.920 --> 0:01:57.560 Normally the you tether these devices. You don't just release 0:01:57.560 --> 0:02:01.160 a weather balloon and say sea, but sometimes you know 0:02:01.200 --> 0:02:04.200 you need to have that GPS element there too. And 0:02:04.760 --> 0:02:07.520 getting this information from the atmosphere is really important because 0:02:07.520 --> 0:02:10.280 it can tell you about how conditions may soon change 0:02:10.440 --> 0:02:16.000 on the ground. It's pretty interesting actually to ever if 0:02:16.040 --> 0:02:18.480 you've ever had a chance to look at some of 0:02:18.520 --> 0:02:23.000 the data pulled from these, because you see how different 0:02:23.040 --> 0:02:26.600 conditions in the atmosphere are compared to what we experience here, 0:02:27.600 --> 0:02:34.200 including some pretty intense winds at higher altitudes. So we've 0:02:34.240 --> 0:02:38.359 got all this information being collected, and before we get 0:02:38.400 --> 0:02:42.040 into space, because that'll be the next step outward, I 0:02:42.080 --> 0:02:43.920 wanted to talk a little bit about what we do 0:02:44.040 --> 0:02:46.480 with all that data. One of the things we do 0:02:46.600 --> 0:02:50.640 is we create databases that have all this information. So 0:02:50.680 --> 0:02:54.000 that let's say that we have a day with pretty 0:02:54.080 --> 0:02:58.000 nice weather, we collect all the information about that. What 0:02:58.120 --> 0:03:01.000 was the atmospheric pressure, what is the temperature, how much 0:03:01.080 --> 0:03:03.640 humidity was in the air, what was the wind speed, 0:03:04.040 --> 0:03:07.640 were there any higher low pressure systems nearby? Were the 0:03:07.760 --> 0:03:09.639 what kind of front had just moved through? All this 0:03:09.720 --> 0:03:12.160 sort of information, we feed it all into a database. 0:03:13.200 --> 0:03:15.640 Collecting that over and over and over again allows us 0:03:15.680 --> 0:03:20.919 to build a better virtual understanding of how weather works, right, 0:03:22.680 --> 0:03:25.360 and we can supplement that with more information as we 0:03:25.440 --> 0:03:29.360 learn more about the weather. Then we would end up 0:03:30.440 --> 0:03:32.880 using that to help us make some predictions about how 0:03:32.919 --> 0:03:36.480 weather might be in the future. And to do that, 0:03:36.520 --> 0:03:41.560 really we use computer models. Typically we would build what 0:03:41.800 --> 0:03:48.720 was called a numerical weather prediction model, the NWP. So 0:03:49.240 --> 0:03:52.160 this is really a model that's made up of a 0:03:52.200 --> 0:03:55.320 bunch of different calculations that take all of the different 0:03:55.400 --> 0:04:00.040 variables into account and tell you, based upon all the 0:04:00.080 --> 0:04:03.440 variables available to us, here's what it looks like the 0:04:03.480 --> 0:04:08.040 weather is going to be like in X amount of time. Right, So, 0:04:08.120 --> 0:04:10.560 whenever we're talking about forecasts, obviously we have to worry 0:04:10.600 --> 0:04:13.360 about what are the current conditions and how far out 0:04:13.400 --> 0:04:17.599 are we trying to predict the weather? And on TV 0:04:17.760 --> 0:04:20.640 you might see five or seven or even these days 0:04:20.680 --> 0:04:23.960 sometimes ten. Yeah. Like if you go to weather dot com, 0:04:24.000 --> 0:04:26.120 they have a ten day forecast, which I always think 0:04:26.240 --> 0:04:29.840 is hilarious. And the reason I think it's hilarious is 0:04:30.480 --> 0:04:34.120 here's how those predictions work. You take all the information 0:04:34.160 --> 0:04:37.120 available to you, you run it through your computer model, 0:04:37.320 --> 0:04:41.600 which factors in these different variables and gives you sort 0:04:41.640 --> 0:04:45.520 of a percentage of probability of what your weather is 0:04:45.520 --> 0:04:48.320 going to be like in the next let's say hour. 0:04:50.040 --> 0:04:52.200 What if you want to look two hours ahead, Well, 0:04:52.240 --> 0:04:54.400 then what they do is they take the prediction that 0:04:54.440 --> 0:05:01.240 they made for an hour from now and extrapolate from there, saying, well, 0:05:01.839 --> 0:05:04.240 if in fact the weather is what we think it's 0:05:04.279 --> 0:05:07.000 going to be like in an hour, this is what 0:05:07.120 --> 0:05:10.599 should look like two hours from now. Well, if you 0:05:10.600 --> 0:05:12.560 want to look at three hours from now, well let's 0:05:12.600 --> 0:05:14.800 take what the results were for two hours from now 0:05:14.800 --> 0:05:17.000 and extrapolate again, and that's what we think it's going 0:05:17.040 --> 0:05:19.880 to be three hours from now. Extend that out to 0:05:19.960 --> 0:05:23.039 ten days. Yeah, and it's going to become less and 0:05:23.520 --> 0:05:29.400 less reliable, Yes, because you're basing your predictions upon the 0:05:29.440 --> 0:05:33.600 results of a previous set of predictions, not upon a 0:05:33.640 --> 0:05:39.799 previous set of actual conditions. Right, So when you're tracing 0:05:39.800 --> 0:05:41.960 it all the way back and your starting point is 0:05:42.160 --> 0:05:46.800 right now, well, clearly, the further out we look, the 0:05:46.839 --> 0:05:49.159 more unreliable the information is going to be, the more 0:05:49.279 --> 0:05:54.120 likely some other variable that we have not anticipated will 0:05:54.160 --> 0:05:58.120 play a larger role or a smaller role, and that 0:05:58.279 --> 0:06:02.240 is going to affect the overall outcome of the of 0:06:02.279 --> 0:06:05.000 what will actually happen. The forecast is the same, but 0:06:05.040 --> 0:06:08.600 the actual thing we experience might be very different, which 0:06:08.640 --> 0:06:11.760 is why if you're planning a picnic and you've got 0:06:11.760 --> 0:06:14.280 ten days out from it and you're looking at the 0:06:14.279 --> 0:06:16.800 weather and it says it's going to be absolutely perfect, 0:06:18.120 --> 0:06:21.679 don't bet the house on it. Yes, that's not necessarily true. 0:06:21.800 --> 0:06:25.080 Not to discredit numerical weather predictions, because a lot of 0:06:25.120 --> 0:06:29.880 science and time goes into it. Yeah, but it's still 0:06:30.240 --> 0:06:33.520 you know, It's the way that I see modern meteorology 0:06:33.640 --> 0:06:37.919 is that over time we have continually built upon basically 0:06:37.960 --> 0:06:41.440 what our ancestors did and just gotten it's gotten more scientific, 0:06:41.520 --> 0:06:46.040 we've gotten better instruments, but it's still looking for patterns. Yeah, 0:06:46.080 --> 0:06:50.120 exactly right. So you might look at the patterns of 0:06:50.839 --> 0:06:54.520 when all of these conditions are in play. Out of 0:06:54.520 --> 0:06:58.400 the last one hundred times that that happened, this is 0:06:58.560 --> 0:07:01.480 how the weather turned out, and we're going to break 0:07:01.480 --> 0:07:04.960 it down. So maybe eighty days out of those one 0:07:05.040 --> 0:07:08.120 hundred days where the conditions were similar to today's, it 0:07:08.160 --> 0:07:11.760 didn't rain at all. It was perfectly sunny, so eighty 0:07:11.760 --> 0:07:14.840 out of one hundred it was lovely. The other twenty 0:07:14.920 --> 0:07:19.160 days it rained and it was just steady rain, and 0:07:19.640 --> 0:07:21.840 that's all there is to it. This is a super 0:07:21.960 --> 0:07:26.000 oversimplified version of what could happen. This is what would 0:07:26.080 --> 0:07:28.280 lead you to say there's a twenty percent chance of rain, 0:07:28.760 --> 0:07:31.280 because he would say, all right, now, the last hundred 0:07:31.280 --> 0:07:35.520 times the weather was exactly like it is today, twenty 0:07:35.560 --> 0:07:38.320 of those times it rained, eighty of those times it 0:07:38.360 --> 0:07:41.040 did not. Therefore, there is a twenty percent chance that 0:07:41.160 --> 0:07:44.400 it will rain. That again is oversimplifying the way it works, 0:07:44.960 --> 0:07:47.920 but generally speaking, that's kind of how they come to 0:07:47.960 --> 0:07:53.040 those determinations, And in fact, there are ways of bolstering 0:07:53.120 --> 0:07:57.080 the NWP by using something called model output statistics, which 0:07:57.160 --> 0:07:59.520 is I kind of just talked about it a little bit. 0:07:59.640 --> 0:08:01.280 I'll just go ahead and touch on it right now. 0:08:01.640 --> 0:08:04.320 It's essentially doing what we were talking about, looking at 0:08:04.360 --> 0:08:09.280 a specific region and the specific outcomes of days that 0:08:09.360 --> 0:08:12.240 had similar conditions to the one you're looking at right now, 0:08:13.160 --> 0:08:16.280 and then you're kind of making an educated guess based 0:08:16.320 --> 0:08:20.920 upon a computer model and actual localized history. I got 0:08:20.960 --> 0:08:22.960 that clear to something up for a lot of people. 0:08:23.080 --> 0:08:25.840 I sure hope so because I've just kind of gone 0:08:25.880 --> 0:08:27.960 with it. You know, I've just seen, oh, twenty percent 0:08:28.080 --> 0:08:30.240 chance of rain, okay, and never really thought about what 0:08:30.320 --> 0:08:33.560 goes into determining that. Well. And I know that there's 0:08:33.559 --> 0:08:36.480 some people who had, you know, when they saw twenty 0:08:36.520 --> 0:08:38.439 percent chance of rain, they thought it meant, oh, it's 0:08:38.480 --> 0:08:41.520 going to rain over twenty percent of the forecast area, 0:08:41.679 --> 0:08:43.480 which means that you know, that would be more like 0:08:43.520 --> 0:08:46.319 scattered showers. That's really what scattered showers means. When you're 0:08:46.360 --> 0:08:50.520 scattered showers, it means that parts of the forecast area 0:08:50.600 --> 0:08:53.119 are expected to get rain, but it will not necessarily 0:08:53.200 --> 0:08:57.640 rain over the entire forecast area. But if you hear 0:08:57.679 --> 0:08:59.440 twenty percent chance of rain, it does not mean that 0:08:59.640 --> 0:09:01.760 eighty percent of the forecast area is going to be 0:09:01.840 --> 0:09:03.400 dry and the other twenty percent it's going to be wet. 0:09:03.440 --> 0:09:05.720 Nor does it mean it will rain for twenty percent 0:09:05.720 --> 0:09:08.760 of the day. In fact, that's part of the problem. 0:09:10.000 --> 0:09:13.880 A prediction of precipitation, the good old pop, the pop 0:09:15.200 --> 0:09:19.920 so pop. That requires a time element to it as well. 0:09:20.080 --> 0:09:22.600 It doesn't mean anything without a time element. So if 0:09:22.640 --> 0:09:25.120 you say there's a twenty percent chance to rain, you 0:09:25.200 --> 0:09:27.480 also need to have an element of time attached to 0:09:27.520 --> 0:09:29.880 that to make it meaningful. So twenty percent chance to 0:09:30.000 --> 0:09:33.439 rain over the next six hours, then you know, all right, 0:09:33.480 --> 0:09:35.280 So it's not saying that's going to be twenty percent 0:09:35.400 --> 0:09:37.679 chance to rain or it's not gonna rain twenty percent 0:09:37.720 --> 0:09:40.280 of the day, just that for the next six hours 0:09:40.320 --> 0:09:42.400 there's a twenty percent chance it will be raining in 0:09:42.440 --> 0:09:46.640 the forecast area. We will be back with more weather 0:09:46.720 --> 0:10:01.160 technology after this quick break, so I hope that demystifies 0:10:01.200 --> 0:10:04.000 some of it. Also, we can talk about radar. One 0:10:04.000 --> 0:10:07.240 of my favorite things to talk about. Radar is awesome, 0:10:07.679 --> 0:10:11.719 favorite character on mash me too. Yeah, well, I think 0:10:12.160 --> 0:10:14.880 it's so adorable, right, Yeah, it's hard not to feel 0:10:14.920 --> 0:10:18.480 for him, and the fact that he can anticipate everything 0:10:18.559 --> 0:10:23.000 his commanding officer wants, and he can even say what 0:10:23.040 --> 0:10:25.600 the commanding officer is saying before the commanding officer has 0:10:25.640 --> 0:10:31.640 finished a sentence is obviously a key part of that operation. 0:10:33.080 --> 0:10:37.040 But we're talking about actual radar, using radar to detect weather. 0:10:37.440 --> 0:10:41.200 You've probably heard Doppler radar when looking at a weather report, like, well, 0:10:41.240 --> 0:10:44.120 let's look at the Doppler radar and see where this 0:10:44.720 --> 0:10:49.720 precipitation is moving in. Doppler radar for weather is different 0:10:49.760 --> 0:10:52.880 from Doppler radar used by say, police officers, who are 0:10:53.360 --> 0:10:56.960 trying to detect if you are speeding. The Doppler radar 0:10:57.120 --> 0:11:01.840 that meteorologists use actually shoots out radio waves in very 0:11:01.960 --> 0:11:06.920 short bursts called pulses, and then the radar listens for 0:11:07.000 --> 0:11:10.280 any echoing pulses coming back to the antenna, and the 0:11:10.320 --> 0:11:14.360 short pulses indicate not just the presence of something out there, 0:11:14.800 --> 0:11:18.480 but whether it's moving and which direction is it moving in. 0:11:20.280 --> 0:11:23.199 Is it moving toward the radar station or away from it. 0:11:23.280 --> 0:11:26.800 If a Doppler radar receiver detect waves of a higher frequency, 0:11:27.400 --> 0:11:31.720 the precipitation particles are moving toward the radar exactly, and 0:11:32.000 --> 0:11:35.679 lower frequencies they're moving away. Yes, Because what's happening is 0:11:35.920 --> 0:11:39.800 it's similar to a Doppler shift. And anyone who's ever 0:11:39.840 --> 0:11:43.720 heard a vehicle with a siren go past yeah, is 0:11:43.760 --> 0:11:46.480 familiar with this. It's a higher pitch as the vehicles 0:11:46.520 --> 0:11:49.400 coming toward you, and a lower pitch as it's moving away. 0:11:49.440 --> 0:11:52.920 What's actually happening is as a vehicle is moving toward you, 0:11:53.160 --> 0:11:56.640 the sound waves it's emitting are being compressed. Now that 0:11:56.760 --> 0:12:00.679 compression creates a higher frequency, which means we detect higher pitch. 0:12:01.720 --> 0:12:06.400 As the vehicle passes, those frequencies are elongated, which means 0:12:06.400 --> 0:12:08.760 a lower pitch. Same thing is true with the radar 0:12:08.800 --> 0:12:11.559 accept Instead of it being a pitch, it's a radio frequency. 0:12:11.640 --> 0:12:14.319 If so, a higher frequency will tell you, yeah, something's 0:12:14.360 --> 0:12:16.840 coming towards you, and a lower frequency will tell you 0:12:17.160 --> 0:12:21.360 something's moving away from you. And also the time between 0:12:21.480 --> 0:12:24.120 when the pulse goes out and when you detect it 0:12:24.160 --> 0:12:29.720 tells you the distance from the radar detection system and 0:12:29.840 --> 0:12:33.400 the precipitation. So you could even say there's a storm 0:12:33.520 --> 0:12:37.960 system that's five miles to the west, it's moving easterly 0:12:38.120 --> 0:12:41.280 at this speed because you've detected it through a series 0:12:41.280 --> 0:12:45.600 of pulses. If you have enough radar detection stations, you 0:12:45.640 --> 0:12:49.880 can even describe the shape of the weather system and 0:12:49.960 --> 0:12:53.880 talk about how some areas are more intense than others. 0:12:53.960 --> 0:12:56.280 You can get all of that information from this approach, 0:12:56.720 --> 0:13:01.440 and it's amazing how this thing works. First of all, 0:13:02.400 --> 0:13:07.760 it's super high power. These radar stations are they're they're 0:13:07.800 --> 0:13:10.480 generating or they're transmitting I should say, at four hundred 0:13:10.480 --> 0:13:14.680 and fifty thousand watts. So your typical microwave oven is 0:13:14.679 --> 0:13:17.400 a thousand watts. Wow, so you need a four hundred 0:13:17.400 --> 0:13:20.520 and fifty of those to equal one of these radar systems. 0:13:21.400 --> 0:13:25.439 So four and fifty thousand watts, and the pulse lasts 0:13:25.520 --> 0:13:29.800 so short as to be unimaginable. It is point zero 0:13:30.040 --> 0:13:35.679 zero zero zero zero one five seven seconds long, or 0:13:35.760 --> 0:13:38.520 one point five seven times ten to the minus six seconds. 0:13:38.679 --> 0:13:42.160 So if you hear the weatherman on TV bragging about 0:13:42.200 --> 0:13:45.640 Doppler radar, there's a reason. It's very impressive. Yeah. I mean, 0:13:45.640 --> 0:13:51.520 you're sitting at a burst of radio signals at such 0:13:51.520 --> 0:13:55.480 a fraction of a second that it is again impossible 0:13:55.480 --> 0:13:59.520 to even imagine. Meanwhile, then it listens for a longer period, 0:13:59.559 --> 0:14:02.000 and by longer I mean relatively longer. It's still a 0:14:02.040 --> 0:14:05.360 fraction of a second. It's point zero zero zero nine 0:14:05.520 --> 0:14:10.040 nine eight four three seconds. So it shoots out a pulse, 0:14:10.800 --> 0:14:13.480 listens for a little while, so it can detect when 0:14:13.520 --> 0:14:16.320 the pulse comes back and what frequency it's at, so 0:14:16.360 --> 0:14:18.240 it knows whether or not a body is moving toward 0:14:18.280 --> 0:14:20.880 it or away from it, and then it does it again. 0:14:21.880 --> 0:14:24.280 But that means, with that amount of time and the 0:14:25.360 --> 0:14:29.400 comparatively large amount of time of listening, for every hour 0:14:29.680 --> 0:14:34.600 of operation, the radio or the radar antenna is only 0:14:34.640 --> 0:14:39.360 shooting out signals for seven seconds out of an entire hour. Wow, 0:14:39.680 --> 0:14:42.120 that means for the fifty nine minutes fifty three seconds, 0:14:42.120 --> 0:14:44.160 it is not sending out a signal. It is listening. 0:14:45.520 --> 0:14:50.160 So for almost a full hour it's listening and only 0:14:50.200 --> 0:14:52.840 for seven seconds is it actively shooting out a signal. 0:14:52.960 --> 0:14:55.200 Can you mentioned it a conversation for someone who talks 0:14:55.200 --> 0:14:58.160 seven seconds out of an hour, it would I any 0:14:58.200 --> 0:15:01.360 conversation with me would last like a decade and before 0:15:01.400 --> 0:15:05.200 you could get a word in edgewise. Yeah, it's it's 0:15:05.320 --> 0:15:08.680 pretty amazing, and you usually would have one of these 0:15:08.880 --> 0:15:14.320 stations shooting out these radio bursts at different angles of elevation. 0:15:14.480 --> 0:15:18.520 These are called elevation slices, and when you go through 0:15:18.760 --> 0:15:22.360 the entire range, you get what was called volume coverage 0:15:22.400 --> 0:15:25.640 pattern or VCP, and that's what tells you what the 0:15:25.680 --> 0:15:29.600 activity is, not just at ground level, but up in 0:15:29.640 --> 0:15:35.480 the atmosphere as well. Toper radar can also detect tornadoes. Yeah. Yeah, 0:15:34.280 --> 0:15:38.400 if if the particles switch from moving toward and then 0:15:38.480 --> 0:15:42.000 away over a small distance, there's a good chance it 0:15:42.040 --> 0:15:45.000 could be a tornado. Yeah, we know a lot about 0:15:45.040 --> 0:15:47.080 those here in the southeast too. We get a lot 0:15:47.080 --> 0:15:50.800 of tornadoes, not as many as places in the you know, 0:15:50.880 --> 0:15:54.000 like in the Midwestern states, things like you know, Oklahoma 0:15:54.000 --> 0:15:56.640 and stuff. I mean, you guys get tornadoes even more 0:15:56.680 --> 0:16:00.160 frequently than we do, but we get them pretty serious. 0:16:00.760 --> 0:16:03.240 Actually this year hasn't been too bad. No, but there 0:16:03.280 --> 0:16:06.160 was one in November, yeah, which is weird because typically 0:16:06.160 --> 0:16:09.680 we get them in the spring. Yes, usually between March 0:16:09.720 --> 0:16:14.120 and June. That's kind of like our let's play it easy. Yeah, 0:16:14.200 --> 0:16:17.240 but you don't wash that on anybody. So no, I 0:16:18.120 --> 0:16:22.680 have been through a close call with a tornado while 0:16:22.720 --> 0:16:26.880 wearing Renaissance Festival gear. That sounds surreal. That was my 0:16:27.120 --> 0:16:29.680 final day when I did my first run at the 0:16:29.680 --> 0:16:33.480 festival in two thousand and one. Wow. Yeah, we had 0:16:33.520 --> 0:16:36.240 a really massive thunderstorm and at one point someone said 0:16:36.280 --> 0:16:39.760 that there was a tornado a tornado watch, but not 0:16:39.840 --> 0:16:43.640 a tornado warning watch, being that the conditions for a 0:16:43.640 --> 0:16:48.000 tornado forming are present, warning being that a tornado has 0:16:48.040 --> 0:16:51.960 actually been spotted in the region, in case you were wondering. 0:16:52.400 --> 0:16:55.480 So now let's talk about satellites and meteorology. So the 0:16:55.520 --> 0:16:58.160 computers are really good for building out those models and 0:16:58.200 --> 0:17:02.040 giving us predictions. The double radars really good at tracking precipitation. 0:17:02.480 --> 0:17:07.159 What do weather satellites do well, they're keeping an eye 0:17:07.600 --> 0:17:11.600 on global weather patterns. But there are two different types 0:17:11.640 --> 0:17:15.159 of weather satellites and they do this in different ways. 0:17:15.200 --> 0:17:20.200 So one is the geostationary weather satellite. Now, geostationary weather 0:17:20.240 --> 0:17:24.919 satellites maintain their relative position over a specific point on 0:17:24.920 --> 0:17:28.160 the Earth. They are at a very high orbit over 0:17:28.240 --> 0:17:32.800 the equator and they're always looking at the same thing 0:17:32.840 --> 0:17:36.480 because their orbit is at the same speed as Earth's rotation, 0:17:37.640 --> 0:17:39.960 not really the same speed, but relative speed. Because it's 0:17:40.000 --> 0:17:43.200 able to stay in that same point over that part 0:17:43.280 --> 0:17:45.840 of the Earth, and so they have to be on 0:17:45.920 --> 0:17:47.879 an equatorial orbit and they have to be at a 0:17:47.880 --> 0:17:51.040 particular altitude for this to work. It's great because it 0:17:51.080 --> 0:17:53.119 means they can keep an eye on a specific region. 0:17:53.240 --> 0:17:56.800 It's lousy because one, they're really far away, so the 0:17:56.840 --> 0:17:59.240 instrumentation you have to put on the satellites has to 0:17:59.240 --> 0:18:03.080 be incredibly sophisticated in order to get good readings from 0:18:03.119 --> 0:18:06.359 that altitude. Plus they have a limited view, right, They're 0:18:06.359 --> 0:18:08.240 always looking at one part of the Earth. They can't 0:18:08.280 --> 0:18:11.720 see anything else outside of that view. Always geostationary yep. 0:18:12.200 --> 0:18:14.840 So the other type you have are satellites that are 0:18:14.840 --> 0:18:18.480 in a polar orbit around the Earth. Polar orbits are interesting. 0:18:18.560 --> 0:18:21.720 So if you think of the Earth on its axis, 0:18:21.760 --> 0:18:25.840 the polar orbit is going parallel to the axis of 0:18:25.880 --> 0:18:29.840 the Earth. It's going perpendicular to the equator. So you 0:18:29.840 --> 0:18:32.200 would think of it as going from north to south 0:18:32.240 --> 0:18:35.439 and then south to north because once it crosses the 0:18:35.440 --> 0:18:38.080 south pole, you can only go north at that point. 0:18:38.119 --> 0:18:41.280 That's the only direction left to you, and it goes 0:18:41.280 --> 0:18:44.960 in that circle, which means these satellites get a full 0:18:45.040 --> 0:18:48.440 view of the entire Earth, because the Earth is rotating 0:18:48.520 --> 0:18:52.520 while it's going in this orbit north south orbit. But 0:18:52.880 --> 0:18:55.760 it also means that you only get a look at 0:18:55.840 --> 0:18:58.480 the same part of the Earth twice in a twenty 0:18:58.480 --> 0:19:01.960 four hour period, since once every twelve hours, you could 0:19:01.960 --> 0:19:04.359 always put another satellite up there, and that way you 0:19:04.359 --> 0:19:08.399 could get you put it on the opposite side of 0:19:08.440 --> 0:19:10.560 the Earth where it's in the same orbit, and then 0:19:10.560 --> 0:19:13.120 you get a look every six hours, just one from 0:19:13.160 --> 0:19:16.600 one satellite and then six hours later one from another satellite. 0:19:17.240 --> 0:19:20.280 But you also get to see everything on the planet, 0:19:20.359 --> 0:19:23.399 So there's your trade off is that you get a 0:19:24.080 --> 0:19:27.600 more comprehensive view, but you don't get a consistent view 0:19:27.880 --> 0:19:29.800 of any one part of the Earth with these kind 0:19:29.840 --> 0:19:33.280 of weather satellites. So a lot of weather surfaces depend 0:19:33.359 --> 0:19:36.000 upon both, yeah, so it's good to have both, yeah. 0:19:36.280 --> 0:19:41.119 And typically they carry devices called radiometers, which usually have 0:19:41.359 --> 0:19:44.840 a small telescope or some sort of antenna, a scanning 0:19:44.840 --> 0:19:47.600 device of some sort, and one or more detectors that 0:19:47.640 --> 0:19:51.080 can pick up visible, infrared or microwave radiation, and they 0:19:51.200 --> 0:19:53.680 use that to take measurements of the Earth and send 0:19:53.720 --> 0:19:57.439 that down to the planet's surface, so that weather stations 0:19:57.480 --> 0:20:00.560 around the world can take that data and crunch it 0:20:00.640 --> 0:20:03.000 and figure out what the heck is going out on 0:20:03.080 --> 0:20:05.200 out there when the frogs are raining from the sky 0:20:05.960 --> 0:20:11.080 apart from amphibious assault, and all of those measurements are 0:20:11.080 --> 0:20:14.640 actually done through little electrical voltages which then get digitized, 0:20:14.800 --> 0:20:18.320 so transformed into digital information before transmitted down to Earth, 0:20:18.320 --> 0:20:21.440 because you know, zapping electricity through space down to the planet, 0:20:21.440 --> 0:20:24.199 it's not the most efficient way of getting information across 0:20:25.000 --> 0:20:26.760 You certainly don't want to have a power chord stretch 0:20:26.800 --> 0:20:28.760 all the way there. That would just be such a pain, 0:20:28.960 --> 0:20:32.480 very inefficient. Yeah. Also with aircraft patterns. Yeah, and if 0:20:32.480 --> 0:20:35.200 you don't have geostationary orbit, it gets wrapped up around 0:20:35.240 --> 0:20:40.240 the planet pretty quickly. Yeah. We will conclude our two 0:20:40.320 --> 0:20:44.679 part episode series about weather attack after this quick break. 0:20:54.280 --> 0:20:58.080 So how do meteorologists do things like predict temperature, like 0:20:58.119 --> 0:21:00.800 predict highs and lows and that kind of stuff? For 0:21:00.920 --> 0:21:03.480 this I went to a website that was written by 0:21:03.520 --> 0:21:08.399 a meteorologist named Jeff Haby, and boy howdy, did it 0:21:08.440 --> 0:21:11.439 suddenly dawn on me how much more complicated this was 0:21:11.480 --> 0:21:15.600 than I had even anticipated. But according to Haby, he 0:21:15.680 --> 0:21:22.520 looks at everything from thermal advection, wind speed, cloud cover, 0:21:22.800 --> 0:21:25.960 dew point, and the number of daylight hours expected for 0:21:26.040 --> 0:21:28.680 that region in order to come up with the prediction 0:21:28.760 --> 0:21:30.240 for the high temperature of the day in the low 0:21:30.280 --> 0:21:32.880 temperature of the day. So what the heck does all 0:21:32.920 --> 0:21:36.879 that mean? So thermal advection, what is that? That refers 0:21:36.920 --> 0:21:40.480 to the transportation of heat by a moving fluid. So 0:21:40.520 --> 0:21:44.920 typically the stuff that affects the advection include the strength 0:21:44.960 --> 0:21:48.119 of wind, So how hard is the wind blowing in 0:21:48.160 --> 0:21:52.840 that region? The temperature gradient between the warmer and colder areas. 0:21:53.000 --> 0:21:55.960 So if one area is warmer than the other, is 0:21:55.960 --> 0:21:58.560 it warmer by like a couple of degrees or is 0:21:58.560 --> 0:22:01.440 it more significant than that is ten degrees fahrenheit, that 0:22:01.480 --> 0:22:06.159 would be a much larger gradient, right, And the angle 0:22:06.240 --> 0:22:09.239 between the wind direction and the temperature gradient, if that 0:22:09.480 --> 0:22:12.359 angle is more narrow, you're going to see a greater 0:22:12.480 --> 0:22:17.000 thermal advection, meaning you'll see more temperature changes moving into 0:22:17.040 --> 0:22:21.520 an area from a different region. So that's just advection. 0:22:22.720 --> 0:22:25.399 That's a lot of play. The other one that you 0:22:25.640 --> 0:22:28.320 other term you might be a little confused by. I mean, 0:22:28.400 --> 0:22:31.560 wind speed makes sense, cloudcover makes sense daylight hours. All 0:22:31.600 --> 0:22:34.199 of that makes sense, but what about dew point? That 0:22:34.280 --> 0:22:36.960 refers to the temperature at which air must be cooled 0:22:37.119 --> 0:22:42.000 at constant barometric pressure for water vapor to condense. So 0:22:42.240 --> 0:22:45.040 that temperature, again is dependent upon things like the actual 0:22:45.040 --> 0:22:49.680 air pressure, right, and so the dew point changes based 0:22:49.720 --> 0:22:53.199 upon those other factors as well. So all those have 0:22:53.280 --> 0:22:56.320 to be taken into account before a meteorologist can forecast 0:22:56.359 --> 0:22:58.120 what the temperature is going to be the next day. 0:22:58.160 --> 0:23:01.399 This is why we're so happy to have those complicated 0:23:01.400 --> 0:23:04.600 computers now, because if you were to keep track of 0:23:04.600 --> 0:23:08.320 this yourself, you probably go bonkers. And then we have 0:23:08.440 --> 0:23:11.600 like the idea of the probability of precipitation, which we 0:23:11.680 --> 0:23:14.320 kind of talked about already, but generally speaking, there's some 0:23:14.359 --> 0:23:20.720 weather services that will only predict rainfall if it's expected 0:23:20.720 --> 0:23:23.840 to be over a certain amount, like point two five millimeters. 0:23:24.080 --> 0:23:26.480 If it's going to be less than point two five millimeters, 0:23:26.560 --> 0:23:30.800 it doesn't even register as rainfall in predictions. You would 0:23:30.800 --> 0:23:35.040 say there's a zero percent chance or whatever, if that's 0:23:35.080 --> 0:23:38.200 what you think is going to be the accumulation. Some 0:23:38.280 --> 0:23:41.800 other ones are like, no any rain at all counts 0:23:42.760 --> 0:23:45.760 if it's one drop of rain it rained in that region, 0:23:46.960 --> 0:23:51.239 so it really depends upon the service. But that we 0:23:51.240 --> 0:23:53.719 already talked about the percentages and what those means, so 0:23:53.760 --> 0:23:56.560 hopefully that clears things up. And again that kind of 0:23:56.560 --> 0:24:00.560 goes into that concept of model output statistics, where you 0:24:01.960 --> 0:24:05.800 correct for your predictions based upon past conditions for a 0:24:05.800 --> 0:24:10.479 particular region. All of this comes together to create the 0:24:10.520 --> 0:24:15.520 weather report that you see. So I think the real 0:24:15.560 --> 0:24:22.760 takeaway here is it's incredible the amount of schooling and 0:24:23.040 --> 0:24:26.320 expertise a meteorologist has to have in order to do 0:24:26.400 --> 0:24:29.439 his or her job properly. Yes, right, like, because you 0:24:29.440 --> 0:24:31.359 see how complicated this is, and you start to have 0:24:31.400 --> 0:24:34.679 an appreciation of all right, they said it was a 0:24:34.800 --> 0:24:37.399