WEBVTT - How Weather Models Work 0:00:04.440 --> 0:00:12.440 Technology with tech Stuff from stuff works dot com. Welcome 0:00:12.520 --> 0:00:16.160 to tech Stuff. I am your host, Jonathan Strickland. I'm 0:00:16.160 --> 0:00:19.560 a senior writer with how stuff works dot com and 0:00:19.600 --> 0:00:22.239 I'm so glad you could join me today here on 0:00:22.320 --> 0:00:25.360 tech Stuff, we like to cover all things technological and 0:00:25.680 --> 0:00:28.680 explain how they work and why they're important. And for 0:00:28.720 --> 0:00:31.480 the last couple of episodes, we've really been focusing on 0:00:31.600 --> 0:00:36.400 meteorology and weather forecasting and the types of technology that 0:00:36.440 --> 0:00:39.280 we used to try and predict the weather. UH. In 0:00:39.400 --> 0:00:42.440 the first episode in this series, we concentrated mainly on 0:00:42.479 --> 0:00:45.760 the science of weather itself, and that's important to understand 0:00:45.800 --> 0:00:49.479 because you begin to pick up on how complicated a 0:00:49.840 --> 0:00:54.200 system whether actually is, especially when you start expanding out 0:00:54.320 --> 0:00:57.240 from a small region to a larger region to a 0:00:57.280 --> 0:01:01.640 global region and you see how interdependent all of these 0:01:01.640 --> 0:01:05.800 different regions are on each other, the brain starts to 0:01:05.880 --> 0:01:08.560 swim a bit. In Part two, we looked at the 0:01:08.680 --> 0:01:14.560 various sensors and tools used to capture information about what 0:01:14.800 --> 0:01:18.360 is going on with the weather. These are the tools 0:01:18.440 --> 0:01:22.559 that meteorologists use in order to feed that information into 0:01:22.640 --> 0:01:27.200 their various weather models. So UH, Today's episode is going 0:01:27.240 --> 0:01:30.120 to focus on those weather models. These are based on 0:01:30.160 --> 0:01:33.720 our understanding of the behavior of weather under different conditions, 0:01:33.760 --> 0:01:36.640 and it's what gives us the confidence to make predictions 0:01:36.640 --> 0:01:41.920 of what will happen next. Now that being said, predictions, 0:01:42.080 --> 0:01:45.080 as we all know, are not guarantees. I'm sure there 0:01:45.120 --> 0:01:47.920 are many of you who have walked out of your 0:01:47.920 --> 0:01:51.640 homes with confidence, dressed in your best clothing, only to 0:01:51.720 --> 0:01:55.720 be plagued by an unexpected downpour at an inopportune time, 0:01:55.880 --> 0:01:58.840 turning into Charlie Brown with that one rain cloud just 0:01:59.000 --> 0:02:02.559 directly overhead. Or you might be one of those people 0:02:02.880 --> 0:02:05.800 that have convinced him or herself that if you have 0:02:05.920 --> 0:02:09.000 an umbrella in your hand, it virtually guarantees that not 0:02:09.120 --> 0:02:12.840 a single drop of rain will fall, that you, by 0:02:12.960 --> 0:02:17.000 virtue of holding the umbrella, have prevented rain from happening. 0:02:17.320 --> 0:02:20.200 As it turns out, predicting the weather is really hard 0:02:20.520 --> 0:02:22.440 for a lot of reasons, though the biggest one is 0:02:22.440 --> 0:02:26.280 that weather is just an incredibly complicated system affected by 0:02:26.360 --> 0:02:29.640 hundreds of variables, and those variables may have a lesser 0:02:29.760 --> 0:02:33.760 or greater effect in different situations. That means there's a 0:02:33.760 --> 0:02:36.959 lot of potential outcomes for any given scenario, and until 0:02:37.000 --> 0:02:40.079 we have a really comprehensive understanding of what's going on 0:02:40.240 --> 0:02:43.440 at all times in our atmosphere. Weather predictions will be 0:02:43.440 --> 0:02:49.200 based primarily on statistical probabilities, not certainties. Before we really 0:02:49.440 --> 0:02:51.960 had a handle on all of those variables, and to 0:02:52.040 --> 0:02:54.880 be honest, we don't completely have a full handle on 0:02:54.919 --> 0:02:58.600 them right now. We based weather predictions off of empirical 0:02:58.720 --> 0:03:03.560 rules that we formed observation. So, in other words, generally speaking, 0:03:03.639 --> 0:03:05.840 if you woke up and looked outside the window and 0:03:05.840 --> 0:03:08.000 you thought, hey, it looks like it might rain today, 0:03:08.080 --> 0:03:09.840 because a couple of weeks ago I looked out the 0:03:09.840 --> 0:03:12.320 window and it looked just like this and it rained 0:03:12.440 --> 0:03:15.519 that day, well that's about as complex as it got. 0:03:15.639 --> 0:03:18.240 I mean, you might have a weather map, like a 0:03:18.320 --> 0:03:21.560 literal map, and you have some things you've written down 0:03:21.560 --> 0:03:23.640 on it. You know that to the west of you 0:03:24.560 --> 0:03:27.919 there's a low pressure system, so you might start using 0:03:27.960 --> 0:03:31.440 that as a guide for what could end up happening. 0:03:31.880 --> 0:03:34.320 But it wasn't a very precise science. It wasn't what 0:03:34.360 --> 0:03:38.200 people were calling a rational approach. It was an empirical approach, 0:03:39.240 --> 0:03:41.480 and over time we began to understand that weather is 0:03:41.480 --> 0:03:46.520 dictated by a host of very complex variables. So meteorologists 0:03:46.520 --> 0:03:51.000 are gathering all of this data about air pressure, temperature, windspeed, 0:03:51.080 --> 0:03:53.920 weather patterns that are nearby, and tons of other factors. 0:03:54.920 --> 0:03:59.440 These things are changing quickly and constantly, meaning it's important 0:03:59.440 --> 0:04:03.640 to look over those observations regularly and adjust projections. And 0:04:03.680 --> 0:04:06.800 if you're not lucky, you may only have a few 0:04:06.840 --> 0:04:11.680 observation stations placed in strategic locations within your particular region, 0:04:12.040 --> 0:04:18.120 which gives you a limited on resolution. So weather forecasting 0:04:18.160 --> 0:04:23.000 is a lot like your displays or your televisions resolutions. 0:04:23.080 --> 0:04:27.040 Very important resolution is all about how many points of 0:04:27.160 --> 0:04:31.040 data do you have within that given area, how representative 0:04:31.720 --> 0:04:35.000 are those observation stations. If you have a single observation 0:04:35.080 --> 0:04:39.000 station for several square miles, well that's not going to 0:04:39.040 --> 0:04:41.440 give you very good resolution, right You're going to have 0:04:41.800 --> 0:04:44.360 a very specific idea of what's going on at one 0:04:44.440 --> 0:04:48.360 point within that area, but everything further out from there 0:04:48.640 --> 0:04:51.719 it's going to be some variation of the information you've 0:04:51.760 --> 0:04:54.520 pulled down. So if you want high resolution, you have 0:04:54.560 --> 0:04:57.760 to have lots of observation stations throughout that same area, 0:04:57.920 --> 0:05:01.640 and you collectively are able to determine what's happening by 0:05:01.680 --> 0:05:05.160 looking at all of them, but obviously that adds a 0:05:05.160 --> 0:05:09.520 lot more information to your calculations. In an ideal world, 0:05:09.920 --> 0:05:13.480 you have all areas densely packed with observation stations, giving 0:05:13.480 --> 0:05:18.440 you amazing consistent resolution and the processing power necessary to 0:05:18.480 --> 0:05:21.200 take all that raw data and crunch it to produce 0:05:21.279 --> 0:05:25.320 reliable weather forecasts at any given moment. But we just 0:05:25.520 --> 0:05:31.600 aren't there yet. So weather models, what's the story on those? Well, 0:05:31.640 --> 0:05:33.920 it helps to look back on the birth of meteorology 0:05:33.960 --> 0:05:37.159 and weather forecasting in the form of numerical weather prediction. 0:05:37.480 --> 0:05:39.559 That's really what we get down to when we start 0:05:39.600 --> 0:05:43.200 talking about weather models. And to do this we actually 0:05:43.200 --> 0:05:45.760 have to backtrack a little bit. I know, we talked 0:05:45.760 --> 0:05:48.719 a lot about the various tools in the last episode 0:05:48.720 --> 0:05:50.920 and we got pretty up to date, but we're gonna 0:05:50.920 --> 0:05:54.440 have to go back to talk about weather models specifically. Now. 0:05:54.440 --> 0:05:57.480 In the nineteenth century, so this is the eighteen hundreds, 0:05:57.600 --> 0:06:01.320 physicists were beginning to suss out the law of thermodynamics. 0:06:02.279 --> 0:06:06.680 These are the basic laws of energy that we UH 0:06:06.680 --> 0:06:11.320 that everything is is UH has to obey, at least 0:06:11.320 --> 0:06:14.200 everything on the macro scale has to obey. And it 0:06:14.240 --> 0:06:18.760 was relatively easy to put hypotheses to test with modest experiments, right, Like, 0:06:18.800 --> 0:06:23.040 you could do tests about fluid dynamics with small contained 0:06:23.279 --> 0:06:27.560 systems and you could limit the variables and make lots 0:06:27.560 --> 0:06:32.160 of observations. That was pretty easy, relatively speaking, But it 0:06:32.240 --> 0:06:35.039 was much more challenging to step back, and I mean 0:06:35.160 --> 0:06:38.120 way way back and see how those same laws applied 0:06:38.120 --> 0:06:41.760 to something as massive as our atmosphere. If you want 0:06:41.760 --> 0:06:45.320 to think about another way, it's one thing to look 0:06:45.400 --> 0:06:49.479 at a maze that has rats running in it. It's 0:06:49.480 --> 0:06:52.640 another thing to try and figure out what the maze 0:06:52.760 --> 0:06:55.680 is like. When you are inside the maze and you 0:06:55.680 --> 0:06:58.159 can only see a small part of it, How do 0:06:58.200 --> 0:07:01.240 you know what the entire layout of the mazes from 0:07:01.279 --> 0:07:03.599 that perspective? So, in other words, the perspective of the 0:07:03.680 --> 0:07:08.120 rats we are inside the actual environment that we want 0:07:08.160 --> 0:07:11.120 to describe. That makes it way more difficult for us 0:07:11.160 --> 0:07:17.400 to uh isolate and weigh every single variable in the system. Well, 0:07:17.440 --> 0:07:21.680 in nineteen o one, there was a professor named Cleveland Abbey. 0:07:21.840 --> 0:07:25.239 He published a piece in a journal called Monthly Weather Review. 0:07:25.400 --> 0:07:28.160 Now I was really sad to discover that this wasn't 0:07:28.160 --> 0:07:32.120 actually a list of reviews for actual weather like Weather 0:07:32.160 --> 0:07:35.760 Today was pretty good. I give it three stars. No 0:07:36.000 --> 0:07:38.600 it It actually was a scholarly journal on the subject 0:07:38.640 --> 0:07:42.760 of meteorology, and Abbey's piece had the title The Physical 0:07:42.840 --> 0:07:47.559 Basis of Long Range Weather Forecasts. And in that piece, 0:07:47.560 --> 0:07:50.119 Abbey pointed out that forecasts of the time were based 0:07:50.160 --> 0:07:54.400 on experience rather than any real knowledge of how weather works, 0:07:54.600 --> 0:07:57.520 and that the physical theories explained the development of whether 0:07:57.560 --> 0:08:01.400 we're either superficial or non existent. So it goes back 0:08:01.400 --> 0:08:05.400 to that example I gave earlier. Weather forecasting was based 0:08:05.440 --> 0:08:09.720 on people's experience with weather, but not knowing how the 0:08:09.760 --> 0:08:13.240 weather was actually working. So you might say, well, I 0:08:13.280 --> 0:08:17.000 think that it may snow tomorrow based upon what the 0:08:17.040 --> 0:08:19.840 conditions are right now, and the fact that I remember 0:08:19.880 --> 0:08:22.080 a day that was like this where it snowed the 0:08:22.120 --> 0:08:27.080 next day. But that's not a very scientific approach ultimately speaking, 0:08:27.080 --> 0:08:30.800 and it doesn't have It is not based upon understanding 0:08:30.840 --> 0:08:35.160 the factors that lead to things like a snowstorm, and 0:08:35.200 --> 0:08:38.280 so Abby was arguing that in order to have real 0:08:38.440 --> 0:08:42.240 weather forecasting prowess, we would have to gain that understanding 0:08:42.360 --> 0:08:47.040 of the underlying factors of weather. Abby asserted that we 0:08:47.120 --> 0:08:50.959 just had to understand the laws of mechanics and heat 0:08:51.320 --> 0:08:54.679 of the atmosphere. Only then, he posited, could we use 0:08:54.720 --> 0:08:57.920 the information to start making more accurate forecasts. And his 0:08:58.040 --> 0:09:00.200 peace would go on to outline what he saw as 0:09:00.280 --> 0:09:04.280 the necessary steps to get there, including a thorough investigation 0:09:04.360 --> 0:09:06.959 of the behaviors of the atmosphere, and he said that 0:09:07.000 --> 0:09:11.199 the science of meteorology is quote essentially the application of 0:09:11.280 --> 0:09:17.280 hydrodynamics and thermodynamics in the atmosphere end quote, So he 0:09:17.400 --> 0:09:22.320 was calling for the establishment of a new area of science, 0:09:22.760 --> 0:09:26.480 specifically within meteorology, something that that would require people to 0:09:26.520 --> 0:09:30.120 dedicate a lot of time to try and understand this 0:09:30.320 --> 0:09:35.400 complex system that is our atmosphere. Then you have a 0:09:35.440 --> 0:09:42.000 Norwegian scientist, Vilhelm Biekness. He was born in Christiania, Norway, 0:09:42.120 --> 0:09:44.560 in eighteen sixty two, and as a young man he 0:09:44.640 --> 0:09:49.840 worked with a notable physicist, Heinrich Hurts Hurts I mentioned 0:09:50.040 --> 0:09:53.200 in our episodes on the history of electricity, you know 0:09:53.320 --> 0:09:58.000 the Hurts. He went on to he being Bakness went 0:09:58.080 --> 0:10:01.800 on to teach applied mechanic and mathematical physics at the 0:10:01.920 --> 0:10:04.839 University of Stockholm, where he sussed out some theorems that 0:10:04.880 --> 0:10:08.760 helped him create a synthesis of hydrodynamics and thermodynamics for 0:10:09.000 --> 0:10:13.560 large scale atmospheric motions, the very thing that Abby was 0:10:13.640 --> 0:10:17.880 calling for. Bierk Nous was the one to to develop 0:10:17.920 --> 0:10:23.600 a very comprehensive model, the first really comprehensive model for that, 0:10:24.040 --> 0:10:26.720 and this led to the development of air mass theory, 0:10:26.880 --> 0:10:30.439 one of the principal ideas upon which we base weather forecasting. 0:10:31.480 --> 0:10:35.200 Now in n Berk Now published a work titled on 0:10:35.280 --> 0:10:39.160 the Dynamics of the Circular Vortex with Applications to the 0:10:39.200 --> 0:10:43.640 atmosphere and to atmospheric vortex and wave motion. And it's 0:10:43.679 --> 0:10:47.400 a real page turner, guys. This is a pretty dense 0:10:48.679 --> 0:10:51.920 piece of of scholarly work. It's considered one of the 0:10:51.920 --> 0:10:55.800 most important scholarly works in the field of meteorology, and 0:10:55.800 --> 0:10:58.160 it was the basis of our understanding of general weather 0:10:58.200 --> 0:11:01.280 pattern behaviors and why they take on the forms the 0:11:01.320 --> 0:11:03.760 way they do. In other words, it was pretty much 0:11:03.800 --> 0:11:07.240 what Professor Abbey was saying was necessary before we took 0:11:07.240 --> 0:11:11.200 a rationally scientific approach to forecasting the weather. Now, what 0:11:11.400 --> 0:11:16.720 Wilhelm illustrated was that the atmosphere and thus weather does 0:11:17.160 --> 0:11:22.280 can be described in math through fluid dynamics factors like 0:11:22.360 --> 0:11:25.760 temperature impact those behaviors, so you have to take that 0:11:25.800 --> 0:11:29.720 into account. And as things change, there's a sort of 0:11:29.800 --> 0:11:34.760 ripple effect. If you change one part of the the system, 0:11:34.800 --> 0:11:37.319 that ripples out and affects the rest of the system 0:11:37.360 --> 0:11:41.120 in different ways depending upon other factors. And nothing in 0:11:41.160 --> 0:11:44.840 the atmosphere is remaining completely unchanged, and as each element 0:11:44.920 --> 0:11:48.360 shifts or cools down, or heats up, or the density 0:11:48.520 --> 0:11:52.360 changes or whatever it may be, it affects other parts. 0:11:52.400 --> 0:11:56.520 So the math gets pretty challenging pretty fast. He further 0:11:56.559 --> 0:11:59.480 went on to create a two step process for rational 0:11:59.559 --> 0:12:03.440 forecast nesting of whether now. The first step was diagnostic, 0:12:03.880 --> 0:12:07.240 which is, in other words, using observations to determine what 0:12:07.440 --> 0:12:10.120 is the present state of the atmosphere. This is where 0:12:10.480 --> 0:12:12.760 you take all those readings and you say what is 0:12:12.800 --> 0:12:16.240 going on right now? That's the diagnostic step, and it's 0:12:16.320 --> 0:12:19.400 absolutely necessary before you can do anything else. You can't 0:12:19.440 --> 0:12:22.160 say what's going to happen next until you have an 0:12:22.200 --> 0:12:26.640 understanding of what is happening right now. The second step 0:12:26.720 --> 0:12:30.680 was prognostic, which meant that you would use that information 0:12:30.720 --> 0:12:34.920 from the diagnostic step and project outwards and say, all right, well, 0:12:35.120 --> 0:12:38.120 based upon what we know is happening right now, what 0:12:38.320 --> 0:12:41.400 is going to happen twelve hours from now, or a 0:12:41.520 --> 0:12:44.679 day from now or two days from now. And you 0:12:44.720 --> 0:12:47.280 would have to use the information you had gathered in 0:12:47.320 --> 0:12:50.600 the diagnostic step, combined with our knowledge of the laws 0:12:50.640 --> 0:12:56.520 of motion for atmospheric masses, to predict what would happen next. Now, 0:12:56.600 --> 0:12:59.840 if you could strip everything away and just look at 0:12:59.840 --> 0:13:02.720 the math, you'd be looking at a collection of what 0:13:02.840 --> 0:13:06.600 are called partial differential equations. The mathematicians out there know 0:13:06.679 --> 0:13:10.160 exactly what I'm talking about. These are equations that deal 0:13:10.200 --> 0:13:14.640 with rates of change with respect to continuous variables. So 0:13:14.679 --> 0:13:19.040 you're not just talking about variables like temperature, pressure, and velocity. 0:13:19.360 --> 0:13:21.840 You are talking about those, but you're also talking about 0:13:21.840 --> 0:13:26.640 the rate of change of those variables. How quickly is 0:13:26.679 --> 0:13:31.320 the temperature changing, how quickly is the pressure changing, etcetera. Now, 0:13:31.320 --> 0:13:35.200 the way you frame and solve these equations defines your 0:13:35.600 --> 0:13:41.439 weather model. Different weather models place different emphasis on these 0:13:41.520 --> 0:13:44.320 variables and the rates of change. All of this boils 0:13:44.320 --> 0:13:48.760 down to a computer program ultimately that solves these equations 0:13:48.840 --> 0:13:52.560 as you have directed. So one model might approximate different 0:13:52.559 --> 0:13:55.960 equations one way and another model does so in a 0:13:56.080 --> 0:13:59.240 different way, and thus you're going to get two different forecasts. 0:13:59.280 --> 0:14:03.320 Consulting these two different models, they might resemble one another, 0:14:03.480 --> 0:14:06.040 but they're taking different pathways to get to their destination, 0:14:06.280 --> 0:14:10.400 so sometimes they might be very different from one another. 0:14:10.800 --> 0:14:13.480 And it's all because of the way you have told 0:14:13.520 --> 0:14:18.400 the program to prioritize the various processes, which ones you know, 0:14:18.400 --> 0:14:23.320 which factors have the most weight and under what circumstances. Now, 0:14:23.360 --> 0:14:25.880 this doesn't necessarily mean one model is by its nature 0:14:25.960 --> 0:14:29.600 superior to the other. Some models are for specific regions 0:14:29.600 --> 0:14:32.080 in the world, and those regions, due to geography and 0:14:32.160 --> 0:14:35.760 general atmospheric motions, may require more importance to be placed 0:14:35.840 --> 0:14:40.280 on certain sets of variables rather than others. Now Berkness 0:14:40.400 --> 0:14:45.760 identified seven variables he saw as critical for accurate weather forecasting. 0:14:46.120 --> 0:14:51.160 That includes pressure, temperature, density, humidity, and then three different 0:14:51.200 --> 0:14:56.160 components of velocity. He also identified seven equations, three therma 0:14:56.800 --> 0:15:00.560 hydro dynamic equations I should say three hydro dynamic equation, emotion, 0:15:01.120 --> 0:15:05.040 the continuity equation, the equation of state, and equations expressing 0:15:05.080 --> 0:15:08.160 the first two laws of thermo dynamics. Now, keep in 0:15:08.200 --> 0:15:11.400 mind that the atmosphere is three dimensional. You have to 0:15:11.480 --> 0:15:16.160 essentially consider any region within that area a three dimensional grid. 0:15:16.800 --> 0:15:19.400 So your grid has an x, y, and z axis, 0:15:20.080 --> 0:15:24.080 and the events within one part of that grid can 0:15:24.120 --> 0:15:28.200 affect other parts of it, particularly atmospheric motion. And you 0:15:28.240 --> 0:15:31.560 need to figure out how to take partial derivatives which 0:15:32.200 --> 0:15:36.680 computers can't really handle, and then turn them into approximate 0:15:36.760 --> 0:15:42.560 partial derivatives that computers can handle instead. This approximation adds 0:15:42.560 --> 0:15:46.520 in a bit of imprecision by its very nature. But 0:15:46.600 --> 0:15:51.240 then's the brakes. And speaking of brakes, let's take a 0:15:51.320 --> 0:16:00.880 quick one right now to thank our sponsor. So getting 0:16:00.920 --> 0:16:06.080 back into forming weather models. There's a meteorologist named Lewis 0:16:06.200 --> 0:16:10.080 Fry Richardson who was influenced by Berkness, and he did 0:16:10.160 --> 0:16:13.520 his best to tackle the problem of numerical weather forecasting, 0:16:13.600 --> 0:16:16.840 but he stated that the sheer amount of computation was 0:16:16.920 --> 0:16:19.960 impractical for the time. This would be in the early 0:16:20.040 --> 0:16:23.200 twentieth century, first couple of decades of the nineteen hundreds. 0:16:23.720 --> 0:16:27.800 He did say, quote, perhaps someday in the dim future, 0:16:28.080 --> 0:16:31.360 it will be possible to advance the computations faster than 0:16:31.400 --> 0:16:34.920 the weather advances. But that is a dream end quote. 0:16:35.240 --> 0:16:37.960 So he's saying, by the time I'm able to work 0:16:37.960 --> 0:16:40.720 out the math, whatever the weather was gonna be has 0:16:40.760 --> 0:16:45.560 already happened. I'm predicting what happened hours ago. Uh. And 0:16:45.560 --> 0:16:47.800 that was a real problem. Was just that again, you 0:16:47.880 --> 0:16:50.720 had these very complex equations with lots of points of 0:16:50.800 --> 0:16:53.440 data and lots of variables that you had to solve for, 0:16:54.080 --> 0:16:56.080 and by the time you would be done with all 0:16:56.080 --> 0:17:01.520 the calculations, the time had passed. So he was saying, 0:17:01.520 --> 0:17:06.480 there is a need for some sort of engine that 0:17:06.560 --> 0:17:11.720 can do computations faster than what humans can do. So 0:17:11.760 --> 0:17:13.960 the math was just too complex to complete without the 0:17:14.080 --> 0:17:17.720 use of that computational engine. One person determined to help 0:17:17.720 --> 0:17:20.680 design such an engine was John von Neumann, who was 0:17:20.720 --> 0:17:24.439 a mathematician who made numerous contributions to the sciences, and 0:17:24.440 --> 0:17:26.639 he realized that some of the more advanced problems in 0:17:26.720 --> 0:17:30.520 hydrodynamics and weather forecasting would benefit from a powerful automatic 0:17:30.560 --> 0:17:34.199 computational machine. He worked on a project at Princeton at 0:17:34.240 --> 0:17:36.960 the Institute for Advanced Studies and it would become known 0:17:37.000 --> 0:17:42.120 as the Electronic Computer Project. Meanwhile, over at the University 0:17:42.119 --> 0:17:46.600 of Pennsylvania's More School of Electrical Engineering, you had J. G. 0:17:46.880 --> 0:17:50.200 Brainerd who was heading up a project, and J. Presspur 0:17:50.280 --> 0:17:53.600 Eckert and John W. Malchley who were working on what 0:17:53.640 --> 0:17:59.399 was called the Electronic Numerical Integrator and Computer or NIAC 0:17:59.760 --> 0:18:03.080 for short, and computer nerds out there, I consider myself 0:18:03.119 --> 0:18:06.040 one of them will kind of bristle at the sound 0:18:06.040 --> 0:18:09.040 of ENNIAC. They might prick up their ears and say, oh, 0:18:09.280 --> 0:18:11.879 I know, I've heard of ENNIAC. ENIAC being one of 0:18:11.880 --> 0:18:16.360 those early early computers in the dawn of the computing age. 0:18:16.720 --> 0:18:20.320 Well brain Nerd, the man who was heading this project, 0:18:20.400 --> 0:18:23.560 invited von Neumann over to the University of Pennsylvania to 0:18:23.640 --> 0:18:25.880 check out ENIAC, and von Neuman would end up having 0:18:25.920 --> 0:18:29.119 these very deep discussions with the team, and those discussions 0:18:29.160 --> 0:18:33.240 would help inform the design of the successor to ENIAC, 0:18:33.680 --> 0:18:36.680 and these early computers would become some of the first 0:18:36.720 --> 0:18:40.639 capable of tackling those difficult computational problems. I was mentioning 0:18:40.640 --> 0:18:44.119 a second ago, and that brings us to the concept 0:18:44.600 --> 0:18:48.000 of the weather model. Now, your weather model is an 0:18:48.040 --> 0:18:51.280 advanced computer program that runs all of these sorts of 0:18:51.320 --> 0:18:54.399 equations and then calculates outcomes. So, in other words, it 0:18:54.520 --> 0:18:57.920 generates your weather forecast based upon those points of data. 0:18:58.680 --> 0:19:01.120 Many of these weather models have been written in four 0:19:01.240 --> 0:19:05.000 chan for Tran, I should say, largely because that's how 0:19:05.040 --> 0:19:08.560 it's been done for decades. So if you've ever chatted 0:19:08.600 --> 0:19:11.000 with somebody and you're saying, why are we doing it 0:19:11.040 --> 0:19:13.080 this way, and they say, it's because it's how we've 0:19:13.119 --> 0:19:15.600 always done it, that's sort of the case with Fortran 0:19:15.840 --> 0:19:19.919 in weather models. Uh, that's one of the reasons. But 0:19:20.440 --> 0:19:26.680 it's also a very useful language that has evolved over time. 0:19:26.720 --> 0:19:29.680 It's not like it was developed and then forgotten about. 0:19:29.800 --> 0:19:33.879 It has received a lot of I hesitate to use 0:19:33.880 --> 0:19:37.679 the word love, but development over the years. Now, this 0:19:37.760 --> 0:19:40.960 four trend program is compiled into machine language. That's the 0:19:41.040 --> 0:19:43.920 language that computers understand, and we'll talk more about that 0:19:44.000 --> 0:19:47.000 in the Programming Languages episode that will be coming up soon. 0:19:47.440 --> 0:19:49.600 So keeping the year out for those episodes, they should 0:19:49.600 --> 0:19:54.159 be following this one shortly. The program, the weather model 0:19:54.240 --> 0:19:56.879 takes all this information, the data fed to it from 0:19:56.960 --> 0:20:01.520 multiple sources, all those observation stations, and all those equations 0:20:01.560 --> 0:20:04.920 based off of fluid dynamics and thermodynamics, and steps through 0:20:05.040 --> 0:20:08.959 in time to simulate what will happen next. So the 0:20:08.960 --> 0:20:13.399 computer is actively trying to simulate the behavior of weather 0:20:13.440 --> 0:20:19.680 patterns based upon our understanding of hydrodynamics, thermodynamics, and all 0:20:19.680 --> 0:20:25.120 of these variables. So it's it's actively simulating the outcomes. 0:20:25.359 --> 0:20:29.679 Now you're getting these simulations in the form of numeric answers. 0:20:29.720 --> 0:20:35.159 It's not like you're looking at a graphic representation of weather. 0:20:35.240 --> 0:20:37.280 You're not, you know, looking at your computer and you 0:20:37.320 --> 0:20:40.080 see a massive storm is roiling across the screen. I'm 0:20:40.119 --> 0:20:42.880 pretty sure that's how Hollywood would do it. But we're 0:20:42.880 --> 0:20:46.560 talking more about lots of numbers, so not as sexy 0:20:46.960 --> 0:20:51.680 as say, watching Twister on Netflix and you're saying, that's 0:20:51.720 --> 0:20:53.879 what the way, what's the what the weather is going 0:20:53.920 --> 0:20:59.119 to be? Uh, that's not exactly the case. Sadly, Maybe 0:20:59.119 --> 0:21:02.520 one day we'll get there, but not not right now now. 0:21:02.560 --> 0:21:06.800 Some simulations can project out for multiple days, and some 0:21:06.880 --> 0:21:10.560 are more immediate. Some look at short range forecast, some 0:21:10.640 --> 0:21:13.439 do mid range and long range as well, and the 0:21:13.480 --> 0:21:16.960 highest amount of accuracy typically is within the next several hours. 0:21:17.400 --> 0:21:19.960 And then, of course the further out you go from 0:21:20.040 --> 0:21:23.160 the moment you gathered all that data and did your 0:21:23.200 --> 0:21:28.040 diagnostic stuff, the more you are likely to diverge from 0:21:28.160 --> 0:21:32.639 reality for your forecast, more uncertainty enters into the picture 0:21:32.760 --> 0:21:36.919 because it's hard to predict how all of those different 0:21:37.000 --> 0:21:41.040 variables are going to uh what what their state will 0:21:41.080 --> 0:21:43.000 be at any given point in the future. And the 0:21:43.000 --> 0:21:46.000 further out you go, the more uncertain you're going to be. Typically, 0:21:46.760 --> 0:21:49.280 So let's make up a hypothetical situation to kind of 0:21:49.320 --> 0:21:53.560 explain what I'm talking about here. Let's say I'm in 0:21:53.600 --> 0:21:57.000 the north of wester Ross and I know winter is coming. 0:21:57.640 --> 0:22:00.760 My weather forecast model is very much focused on atmospheric 0:22:00.800 --> 0:22:04.320 movements from beyond the wall and less concerned with other 0:22:04.440 --> 0:22:09.320 variables like maybe humidity or I don't know, dragons, because 0:22:09.400 --> 0:22:11.919 humidity and dragons don't play such a large role in 0:22:11.920 --> 0:22:15.440 the weather patterns of my region, right, I mean, I'm 0:22:15.480 --> 0:22:18.879 one of the Starks in this hypothesis. The model I 0:22:18.920 --> 0:22:22.280 have created is as accurate a representation of how patterns 0:22:22.320 --> 0:22:25.320 emerge and behave in my region as I can get 0:22:25.320 --> 0:22:28.439 my hands on. So that's what I rely upon. But 0:22:28.520 --> 0:22:32.800 let's say you in your fancy pants King's landing house 0:22:33.240 --> 0:22:36.240 are concerned with trade winds coming in from out over 0:22:36.280 --> 0:22:39.560 the sea, because that's a large influencer of the weather 0:22:39.600 --> 0:22:43.440 in your area. So your weather model takes that into 0:22:43.480 --> 0:22:46.320 account and gives it greater weight than some of the 0:22:46.400 --> 0:22:49.159 variables that I'm concerned with. And this is so that 0:22:49.240 --> 0:22:53.040 you can create accurate forecasts for your area. Your model 0:22:53.080 --> 0:22:55.960 and my model aren't equivalent. Your model would not work 0:22:55.960 --> 0:22:59.160 as well in my region, and vice versa. And neither 0:22:59.240 --> 0:23:02.480 model is comp inhensive, which means neither model covers all 0:23:02.520 --> 0:23:05.800 of wester Roast. That's very much regional. Now in the 0:23:05.840 --> 0:23:11.320 real world spoiler alert, Game of Thrones isn't real. We 0:23:11.480 --> 0:23:15.320 sometimes find that our computer models are mostly good, but 0:23:15.480 --> 0:23:19.960 not perfect. Some may, under certain conditions under or over 0:23:20.480 --> 0:23:23.399 estimate the temperature for example. Now, this could happen for 0:23:23.520 --> 0:23:25.760 lots of different reasons, such as, you might have a 0:23:25.800 --> 0:23:27.880 region that's close to the ocean, and the ocean could 0:23:27.920 --> 0:23:31.040 affect the temperature in ways that the model is not 0:23:31.320 --> 0:23:35.520 quite capable of accounting for. So you might experience more 0:23:35.600 --> 0:23:38.960 windy conditions than other areas, and the wind may affect 0:23:38.960 --> 0:23:42.720 temperatures in ways that the model can anticipate. The wave 0:23:42.800 --> 0:23:46.880 dynamics could affect whether in ways that the model can't anticipate, 0:23:47.960 --> 0:23:50.119 so you still have meteorologists who are dealing with this, 0:23:50.200 --> 0:23:53.520 and they're fudging the numbers a bit once they've been processed, 0:23:53.560 --> 0:23:58.080 because you learn over time how well your model does 0:23:58.320 --> 0:24:02.119 versus reality. So you can look at the results of 0:24:02.160 --> 0:24:05.600 your model, what does the predictions say, and then you 0:24:05.640 --> 0:24:09.720 can compare that against the actual results that you get 0:24:09.760 --> 0:24:12.080 just by waiting around. Right, you wait around and you 0:24:12.119 --> 0:24:15.320 see what actually happens. You compare that to the forecast 0:24:15.359 --> 0:24:17.960 that your model gave, and you start to look and 0:24:18.000 --> 0:24:21.000 see if there's any any adjustment that needs to be made, 0:24:21.080 --> 0:24:23.640 or in some cases you may just say, well, this 0:24:23.680 --> 0:24:28.440 model is frequently about two degrees warmer than what really happens, 0:24:28.520 --> 0:24:32.080 so we're going to build in an adjustment. We will 0:24:32.119 --> 0:24:36.760 automatically no to decrease the temperature forecast by two degrees 0:24:37.359 --> 0:24:40.000 from this model, and that we are more likely to 0:24:40.240 --> 0:24:43.680 hit on what the actual temperature will be. This happens 0:24:43.720 --> 0:24:46.560 all the time with lots of computer models, not just 0:24:46.600 --> 0:24:50.879 for temperature, but for other variables as well, and really 0:24:51.080 --> 0:24:53.320 we should expect this to continue to happen because we 0:24:53.359 --> 0:24:57.320 cannot have a perfect understanding of how everything is going 0:24:57.359 --> 0:25:00.919 to be and builded into a computer, not yet, possibly 0:25:01.000 --> 0:25:05.320 not ever. It is so complex and so dependent upon 0:25:05.359 --> 0:25:08.439