 As Tim was saying, I am a scientist at Encore and I work a lot in winter weather. And I'm going to be sharing you some work that I've been doing related to ground de-icing. Let's see if I can get this to work. Here we go. Okay. So the question that I want to try to answer today and that I've been trying to answer in my research is why is it important to measure snow? So if you look at the mountains, all of you I think live in Colorado, we know about snow and the importance of snow for going skiing or sledding or having fun outside. And we know that snow in the mountains is important to agriculture because it melts and comes down to the plains and farmers use it to water their crops. So that's all very important. But another important reason to measure snow is when we travel. When we travel on commercial airplanes on regular airplanes like United Airlines, when it's snowing like it is right now in the east coast of the United States, you have to be very careful when you take off because snow will have a significant impact on the performance of an aircraft like a 757 or, you know, big commercial airplane. Let's get into this a little bit more. I just wanted to mention that we do a lot of collaborative research at NCAR. And I've listed some of my collaborators, some of them are not from NCAR, some of them are from NOAA. These guys are from Southeast United States, NOAA. And I also work with some folks from Italy, Matteo Collies from Italy, and Julie Terrio is from Canada. A very international group of scientists working on snow. It snows everywhere, everywhere around the world. So let's go to the next slide. And this is what happens when it's snowing out or there's snow on a wing, and you have to take off and go someplace. It's not safe for an aircraft to take off with snow on its wings because it impacts the lift and the drag on the aircraft. So as a result, every airline has to get de-iced. Now what do I mean by de-iced? De-ice means that you have to remove the snow and ice from a wing before it can take off. So the way they do it now, nowadays, is they use something called de-icing fluids. And de-icing fluids are different colors like there's a pink one on the right and then there's a green one. And the pink one is mostly used to remove the ice and the green one is used to protect against ice forming again. So it's sort of like the antifreeze in your car, if you're familiar with that at all. In fact, the de-icing fluids are typically some kind of antifreeze fluid. So when the snow falls into it, it melts and that's essentially how the antifreeze works in your car. It doesn't freeze at normal at 32 degrees Fahrenheit. Roy, I had a question about the colors. It's a little hard to tell the pink and the green in this photo, but if you were in that plane looking out the window and it was daytime, might you be able to see the color? Yeah, you can see the colors. What they typically do is they first remove the ice with the pink one. They call that type 1 fluid. And that's just a hot fluid. They heat it to about 100 degrees Celsius and they're boiling and they get rid of all the ice and snow. And then they put on the green fluid, which is usually called a type 4 fluid, but it's called anti-icing fluid. So it's anti-snow formation. So that's a thicker fluid that absorbs the snow and causes it to melt. So it's like water. And then when the aircraft takes off, the type 4 fluid becomes like water. It's like molasses when it goes on the plane and then it has a special property that once it feels wind shear over the top of it, it turns into a fluid that flows off. So that's why there's two different fluids. Type 1 is more like water, just hot water, but with the icing fluid in and type 4 is thick like molasses, but has special property that it turns into water when the plane takes off so that it runs off because you don't want that fluid on the plane when you're flying because that'll cause a lot of trouble in controlling the aircraft. I didn't know that. So I learned a lot of this when I got into this field. So normally I do winter weather research, but I work in the research applications laboratory. So the airline industry came to us and said, hey, we need help with weather related to aircraft icing and aircraft de-icing. So this is the part of the work that has involved me with aircraft de-icing. So I got to meet some of the United Airlines guys who are, there's a guy sitting in each of those little yellow cabins and I met some of those guys and they told me, they taught me how they do de-icing and I taught them a little bit about winter weather. So it was a great collaboration and interaction. I'm going to get a little scientific on you here. I'm going to talk about how the icing fluids are tested. So there's a couple of terminologies I wanted to mention to you. One is endurance time. A particular de-icing fluid, say type one, which is that yellow fluid or pink fluid, sorry, and type four last before they don't absorb the snow anymore. So remember, these are essentially diluted fluids that anti-icing fluids like the antifreeze in your car. And when you put snow into it, it dilutes it. And then once it gets dilute enough, it runs off and it could cause the fluid to freeze. So that's what they call the endurance time or the failure time. How long will a particular fluid last? So if I spray it on the aircraft, it only lasts, the pink fluid lasts only 10 minutes. So you have to take off within 10 minutes. So a pilot has to know that information. Well, how does he know that? Well, let's see if I can get my, or here's my slide movement. How does he know that? Well, in the laboratory, we actually test these fluids and we actually calculate the precipitation rate or the snowfall rate. And this unit here is grams per decimator script. This tells you how much water is in the snow. And endurance time is the amount of time that a particular de-icing fluid will last. This happens to be a type four octagon fluid. It's made by a company named Octagon. So how, how does the pilot know the precipitation rate and the endurance time? Well, what they do, I'm trying to get my, there we go. What they do is they determine when there's light and very light precipitation rates. So zero to 10 is very light. This unit converts to millimeters per hour if you divide it by 10. So 10 divided by 10 is one. So this is one millimeter an hour. So very light snow is, is here, moderate snow is over here. So if you have a type of fluid and, and you have moderate snow, then you might say, well, maybe I have 40 minutes, or if you want to be conservative, you can go up here and say, maybe I have 110 minutes. But usually you're conservative and say, well, probably have 40 minutes. So the aircraft has to take off in 40 minutes. If you have heavy snow, then you, you're greater than 2.5 or 25 grams of dust meter per hour. So the pilots actually have tables. This is a table that a pilot will use to when he's operating under aircraft de-icing conditions. And what it was shown here are numbers. These numbers are the time that he has until that fluid fails. So let's say, and over here is the outside air temperature. So he goes and calculates or determines what's the outside air temperature. Let's say it was minus three or 27 degrees Fahrenheit. And he goes over here and he says, okay, I'm in snow conditions and I'm in light snow. And if I'm in light snow, I have eight to 14 minutes of time before I need to go get re-de-iced. So basically it tells him how much time he has before he has to take off. And if the fluid, if he goes past that 14 minutes and he's in light snow, then he needs to go back and get re-de-iced. So it's very important that he knows that for safety reasons and these columns have been devised so that the pilots will know that. Well, how does the pilot know it's light, moderate or heavy snow? Well, what he does is he listens to a radio frequency from the National Weather Service. And the National Weather Service determines light, moderate, heavy snow by visibility. So that's very different than the amount of water in the snow. And this is the research part that I got involved with in my question was, well, does visibility work to calculate the amount of water in the snow? So if you look here, I have for light snow, if the visibility in snow is greater than half a mile, then it's light. If it's being half a mile and a quarter of a mile, it's moderate and greater than a quarter mile, it's heavy. So does that correspond to the amount of water and snow? And that's the question I asked. And that got me into the scientific questions of looking at real snow. And so this is something I learned in school. These are different snow crystal types. These are stellar or dendritic crystals as you get more branches. You can look on your, when it's snowing outside, you can look on your sleeve when the snow lands and see what kind of crystal you have. This is stellar or dendritic crystal. The one on the right is the sort of a stellar with heavy rhyming. Rhyming means that the cloud droplets in the cloud have frozen onto the crystal. So you can see that it's still six-sided, but it's tended to disappear. And every snowflake is different as you've heard. These are grapple or snow pellets. These are very heavily rhymed crystals. So once this guy gets a lot of frozen cloud droplets and starts looking like this, sometimes the crystals look like needles. So getting back to the science of the whole problem, the question I asked, or the question I asked myself is, is the visibility through a dendritic crystal or snow pellet the same as through needles? Or are these or these other crystals? And so I decided to do some research on that. And this is a plot of some of my data. All the little dots are not, some of them are real, some of them are bad graphics, but a lot of these dots are actual data points that I collected at a field site we have in south of Boulder. And these lines are theories. And so what I plotted here is the snowfall rate that I measured with an instrument versus visibility that I measured with an instrument and also measured it with my eye. We had a line of telephone poles that we would look at. So let's say the, I want to estimate a snowfall rate of 1.7 millimeters per hour. And I want to use visibility. So what would it be if I use visibility? Well, visibility would say there's only one point here that is 1.7 millimeters per hour in terms of visibility. But in reality, if my visibility was say between light and moderate, my actual snowfall rate could vary between 0.1 millimeters per hour to over 10 millimeters per hour. And the dangerous part is that my estimate by visibility could be wrong and it could be wrong on this side of the curve, which means that my like the moderate snow could actually be more like moderate to heavy. And remember I told you about snow pellets. Well, that's what, that's what happens. These snow pellets are very small and dense. And so you can see right through them through the air when they're snowing with snow pellets whereas the dendritic snow tends to be blocked more. So it turns out that visibility is not a good way to measure snow. So we have to measure it with an instrument. And the other thing that I discovered and thought about was one day I was at LaGuardia Airport in New York City and I landed at 3pm and it was snowing. And I looked outside. And what I found out was when it became dark, it looked like the snow disappeared. And I thought, well, it was just snowing, you know, five minutes ago and went outside and it was still snowing. And that little episode made me think about nighttime versus daytime visibility. And we did some more calculations and some theory. And what we found is that the nighttime visibility is a factor of two larger than daytime visibility. So that means I could go from light snow or from heavy snow in the daytime. And just because it became dark, it would suddenly become moderate snow by visibility. And that was not, that's not a good thing. So based on all that research, we came up with a way to improve the estimation of the intensity of snowfall rate and we give that information to pilots. In fact, one of the organizations we're working with is UPS in Louisville, Kentucky, which is distributing the vaccine. So what we gave them was, was this kind of product where we actually have the liquid water equivalent of snowfall, instead of visibility. And we indicate every minute, whether it's light snow, moderate snow, or heavy snow, so they can use that to determine how long they have for their de-icing fluids. And that's today, I'm hoping that they're using it and hopefully getting the vaccine out on time. That was amazing. I did interrupt. So I want to make sure we don't run out of time. And I think that was probably the quickest summary of a question to actual delivery of a product and application that I think I've ever seen. That was amazing. I would let you know that there were some great questions about the machine that actually sprays the plane. So that's probably going on in Kentucky right now. That's right. Yes, because they do, are they having snow? I think they are having snow in the East Coast. They had snow. I think the storm has moved up towards Maine now in Boston. So I think they're past it, but I'm done. That's my last slide. So perfect timing. Excellent. And did you have any questions that you would like to pose to our audience? I need to get them to think about the, you know, how to look at it because you've described it very well. It's snowing outside, look at the visibility and try to estimate whether it's light, moderate, heavy snow and take a look at, put your sleeve out and look at the snow crystal types and see if you can correlate the type of snow crystals and visibility. And we did have, we had a lot of questions about the actual process of spraying the trucks. Would it be okay if we went back to that slide? And we'll let any other questions come into the chat while we're looking at that picture again. It looks sort of like an excavator. Somebody said it looks sort of like an excavator. And I was describing it's like a booth that floats up in the air and what's happening is that's literally like a fire hose spraying those fluids. So there's a hose that attaches to this. So this is a hose. And you can't see the, actually you can see the sort of the truck here. This column is attached to this truck. And in this truck they have a reservoir of the icing fluid. So this guy pushes a valve or it has like a trigger switch. And that controls the speed at which the icing fluid comes out of the nozzle. I think this is all pink fluid because you can see pink on the ground here as well. So this is type one. So they're just getting rid of all the snow on the top of the aircraft. Excellent. We just had a question come in. Do you always get to work with very practical real life applications like this? Do I always get to work on this kind of stuff? Yeah, practical. Well, when I started this job, I had no idea what I was going to get into. What my first part of the job was to try to bring weather information to the aircraft, the icing community. So the first thing I did is had them look at the weather radar, which you guys probably look at every day when it's snowing. At least I do. But the weather radar, when you watch the news, the weather on the news, on the nightly news, they always show the weather radar. And that was something when I started this in the 90s, the weather radar wasn't as common. So the first thing we did when I got started was give them the weather radar information. And I realized I would and I was trying to convert the radar, the radar dated to snowfall rate. Well, I realized that's not simple to do because snow, it's the same problem has has many different crystal types. And so the radar return is different for every snow crystal type. Once I figured that out, then I thought, well, what about visibility and snow and so every one thing led to another so I didn't start out thinking about this in this way but but thinking of their problem and what they needed the information they needed. I could then relate my weather knowledge to their applied problem. Yeah, some of our viewers could possibly try this at home next time it's snowing and, and guess how far a plane could see or pilot could see. I think you could sit at home and look, look outside and and see how far you can see, you'd have to, you know, get you know know how far a certain tree is or some object that you can see. And try to correlate that with the visibility. I mean, I mean when it's snowing heavily it gets really you know you can't see very far. The question is, is really when you get to moderate snow. That's when it gets tricky because you can sort of see and you can sort of operate a moderate snow but sometimes you can get fooled by visibility so that's why it's much better to actually measure the rate with the snow gauge or some instrument. Excellent. And everyone who joins is has to tell us kind of what is the, what's your favorite part of your job. My favorite part of the job is that nobody tells me what to do I can do whatever I want. I like this out. So, you asked me do it we all get to do this well I get to do what I think is the right thing to do and this is what I thought was the right thing to do. Oh my goodness that's great, the creative part of my job that I like the best, because this, this whole topic didn't exist until like I started working on it. So, do you have any advice for young people. That's the best part of my job. No, I don't have a boss. Do you have any advice for young people with us if they want to be a scientist or how to think more like a time well if you if you enjoy a math and science. That's a good base for starting to be a scientist but I think you know you have to think out of the box a little bit and be creative and question assumptions so when I got into this particular job. I questioned the assumption that the light moderate heavy snow by visibility could be a good way for an airline to measure the light moderate heavy intensity of snow based on the amount of water in the snow that was basically questioning an assumption that had been true for 25 30 years. That's how they had been doing operations and the the airlines, the FAA was about to pass a rule that required air air required pilots to use snowfall intensity estimated by visibility. That's the year I after I got you know, the year I got started and I stopped that that that the rule making. And instead they have now. Now the rules are that you need to take into account day and night and you need to think about the liquid water equivalent of the snowfall rate, in order to estimate the amount of time that a fluid has. Excellent. We do have a question. Is it okay if I if someone has their hand up is it okay if we let them ask that question. Yeah, absolutely. Okay. Kelly Davidson yes you can unmute and ask if you'd like. What is the machine called that sprays the plane. What is it called. They, they have different names but they're usually called the icing trucks. And usually they're a truck that has. They fill it up with the icing fluid, which is typically antifreeze, and they will drive it to the aircraft, and they usually have a dicing pad like, if you ever fly with United in the wintertime. In a particular location where they where they parked the aircraft, and then they say okay pilot will get online and say oh I need to deice the aircraft with the snow and the wing. So he'll stop. And most of the time they turn off the engines, and then they'll have to wait for 1050 minutes while these dicing trucks drive to the aircraft and spray, spray it and remove all the snow and ice. Can you answer your question. Yes, but also right now I'm sort of imagining a gas truck with arm on it with sort of a booth. Right, it kind of gas, it looks like a gas truck, but instead of gas they put in antifreeze the icing fluid. Now the icing fluid isn't just antifreeze like it's in your car, they have special, special additives that they put in the icing fluid so it's so you have to buy it from a particular company there's about five or six different companies in the world that sell the icing fluids. So every airline will will will either do their own deicing or hire somebody to do their their deicing. And that means at the beginning of the winter they have to order fluid and store it in a tank someplace, and then put it in this truck when it's starting to snow so it's important for an airline to know when it's going to snow because they have to get ready to do all this deicing work. So that's another reason why it's important to give them warning about snow. Thank you for answering my question that did a lot for me. Excellent and you know unfortunately we we are right at time a little bit over actually, and we are just everybody knows what we're going to think right here just a second but we will be doing this again after the holidays I'm going to take a break and then on this will start again. And there will be a, I just put the link to our website in the chat. So you may have to copy that I'm not sure it's live you might have to copy it and paste it. But yeah, if we could everybody in the chat. If you'd like to say thanks go ahead and put that in the chat window. And the next thing that I'm going to do is I'm going to paste the URL for our young people grades five to 12 to head over to if you would, to give us a little feedback and I'm not sure about pay for it will turn out one more time. That's Roy we got to thank you from our young visitors there and I'd like to thanks as well. And it'll have any questions. Continuations, please do find our contact about email address in there. There you go you can shoot me a question I'll get it over to Roy and thank you all for joining us. Thank you for listening and hope you learned a little bit about the icing and winter weather and snow. Fantastic. Bye bye. Thank you for listening. Bye bye. Bye now. Goodbye.