Planet NOAA Podcast Episode 9: Charting Earth’s course

Transcript

[Planet NOAA theme music plays]

SYMONE BARKLEY (HOST): Welcome back to Planet NOAA! I’m your host, Symone Barkley. Did you NOAA that the National Oceanic and Atmospheric Administration shapes our nation’s positioning activities? That includes determining latitude, longitude, elevation and shoreline information, plus other measurements that are crucial for positioning. Today, our scientists will dig deep into geodesy, or the science of measuring and understanding our planet’s geometric shape, orientation in space, and gravity field.

[NOAA in the News theme music plays]

HOST: I’m here with Public Affairs Specialist, Climate Scientist, and NOAA in the News correspondent Tom DiLiberto, who’s got some hot topics for us today.

TOM DILIBERTO: You bet I do! Symone, we talk a lot about heat on Planet NOAA. Although it may be cooling down outside, heatstroke remains a very real risk even in lower temperatures, especially for children, whose body temperature rises three to five times faster than adults. Heatstroke starts when the core body temperature reaches approximately 104 degrees, and an internal temperature of 107 degrees can be fatal for children. A car can heat up by as much as 20 degrees in 10 minutes, even if the vehicle’s windows are down. And, believe it or not, heatstroke can occur in cooler temps as low as 57 degrees — this isn’t limited to hot summer months, especially as we see warmer falls on record. So, the folks at the U.S. Department of Transportation want to remind you that once you park your car, you should stop, look in your backseat, and lock the doors once you’ve exited. It only takes a second! Making a habit of looking in the backseat every time you exit your car, locking the vehicle and putting the keys and fobs out of reach, and never leaving a child in a car, not even for a minute, could save their life.

HOST: Tom, that’s an important reminder. We’ve got to look out for our littles! Now, we’re taking a deep dive into geodesy and mapping today. What’s going on in the NOAAverse on the subject of charting and imagery?

DILIBERTO: So, September 24, 2024 actually marks the 25th anniversary of the IKONOS-2 launch, which was the world’s first commercial high-resolution imaging satellite. IKONOS-2 was decommissioned back in 2015, but during its 15-year mission life, it produced a whopping 597,802 public images for users. A quarter century after its launch in 1999, we spoke to Chuck Wooldridge, Director of International and Interagency Affairs at the NOAA Satellite and Information Service, about what made the IKONOS-2 satellite unique. Let’s take a listen: 

CHARLES WOOLDRIDGE: In order for a company to operate a remote sensing satellite, it had to be first licensed, and that license would be granted by NOAA, and in fact, the office that I was working in. Its importance was that it was the first such commercial mission that had been authorized or licensed by a government agency and put into space that had capabilities that were nearing what only military and intelligence spacecraft could provide at the time…with different spectral bands that also could help in agriculture, forestry, mining, you know, a number of different sort of sectors could purchase that imagery for their own needs. The license was issued in ‘94. It was launched in ‘99. And then we’ve seen, you know, so much has changed since those first systems.

HOST: Wow, that’s incredible. Rest in peace, IKONOS.

DILIBERTO: IKONOS? More like I-CONIC HOST!

HOST: Aww, thanks Tom! And thank you for the actually good joke.

DILIBERTO: IKO-KNOW! It was just the satell-RIGHT tone.

HOST: [Sighs] I walked into that one. 

[Did You NOAA theme music plays]

HOST: I’m here with Planet NOAA’s resident trivia expert and NOAA Heritage correspondent, Tara Garwood. Tara, what can you tell us about the origins of geodesy here at NOAA?

TARA GARWOOD: That actually dates back to before NOAA as we NOAA-it existed! In 1807, the nation’s very first scientific agency was born in the shape of the United States Survey of the Coast. By 1878, as geodesy had become a more prominent part of the agency’s work, it was renamed as the U.S. Coast and Geodetic Survey. When several agencies combined to form NOAA’s predecessor, the Environmental Science Services Administration, or ESSA, the Geodesy Division remained a significant part of it. Finally, ESSA became part of NOAA in 1970, which gave rise to the National Geodetic Survey as we know it today. Lots of name changes – and that’s just the short version!

HOST: Scientific duties aside, what was it like to work for the Coast and Geodetic Survey under ESSA?

GARWOOD: Honestly, that may depend on what you see in the mirror every morning! In 1967, there were six women in ESSA’s 50-person Geodesy division. We unearthed a July 1967 edition of ESSA World, a quarterly publication with staff feature stories, that highlighted the first few women breaking the mold in a primarily male-dominated field. Here are some outtakes:  

BOB SCHWARTZ: Would you believe forty-four men and six women and no problems? This is the case in the Coast and Geodetic Survey’s Geodesy Division, where ESSA’s 50 geodesists are employed. ESSA’s lady geodesists — among the few in government service — have carved a solid niche in a profession begun in the United States in 1816 and kept a masculine domain until World War II. The convenience of the bus stop at the door of the Commerce Department launched one career, and one lady was “invited” into the elite club. The average woman is not physically or psychologically conditioned to expect her duties to include carrying heavy instruments, negotiating 90-foot towers, and working outside at night. Therefore, simply because they are women, ESSA’s lady geodesists are limited to some extent because they lack the practical experience and insight into the profession the men gain from working regularly on field parties. 

HOST: Oh, nah, that’s absolutely crazy!

GARWOOD: The modern day equivalent of the U.S. Coast and Geodetic Survey, which is called the National Geodetic Survey, or NGS, has no shortage of incredible, trailblazing women scientists and leaders. That actually includes the most recent Director of NGS, Juliana Blackwell, who shared a bit about her experience at the helm with the NOAA Heritage Oral History Project. We’ll hear more from Juliana right after this.

[Roundtable theme music plays]

HOST: Over the years, NOAA has revolutionized the way that we understand our planet through a field called geodesy. That’s the science of accurately measuring and understanding the Earth’s geometric shape, orientation in space, and gravity field. Today, we’ll take a deep dive into geodesy, charting and mapping with three special guests. First, I’m excited to invite Dr. Daniel Roman to join us today. He’s served for 25 years with the National Geodetic Survey in various roles: as Chief of the Spatial Reference System Division, then as Chief Geodesist. Now, Dr. Roman is our agency’s Senior Advisor for Geodesy. Welcome, Dan!

DR. DANIEL ROMAN: Thank you, Symone.

HOST: Also joining us is Captain Sam Greenaway, the Chief of the Hydrographic Surveys Division at the Office of Coast Survey. Sam is responsible for surveying, finding, or contracting for mapping data in US waters. Sam, thanks for being here! 

CAPTAIN SAM GREENAWAY: Thanks for the invitation, Symone. It’s great to have the opportunity to talk about mapping and certainly welcome the opportunity to talk about geodesy as well. 

HOST: We’re also here with Dr. Vijay Tallapragada. He is the Senior Scientist for the Environmental Modeling Center at the National Centers for Environmental Prediction, or NCEP. At NCEP, he advances community-based complex coupled Earth system models for weather and climate prediction systems. Vijay, glad to have you with us today.

DR. VIJAY TALLAPRAGADA: My pleasure.

HOST: To start, I’d love to hear a bit more about each of you, and how you found yourselves at NOAA.

GREENAWAY: Yeah, sure. So I’ve been working for NOAA for just a little over 20 years now. I started out as a NOAA Corps officer, so our uniformed service. I was sent out on my first assignment to one of our survey ships up in Alaska. I’d grown up with the water using the nautical chart, using NOAA’s products, and that was really neat to be making them, to doing the surveys in remote areas and really understanding what’s behind those products that I’d used for so long. I’ve stayed with it for, and a number of different assignments, both on ships and onshore, largely connected with the hydrographic survey mission, and up to my last assignment at sea was commanding officer of that ship nearly 18 years later. So right now, I’m responsible for all hydrographic survey acquisition, whether we contract for that, whether we use our NOAA fleet to go acquire that data, or more and more, finding data that other people have acquired; we call that external source data and make the most use of that.

TALLAPRAGADA: You know, I have a long history of model development. And my background and education was in meteorology and atmospheric sciences. I joined NCEP EMC, [the Environmental Modeling Center at the National Centers for Environmental Prediction], as a hurricane modeler, and I developed the hurricane weather research and forecasting system that was operational in 2007. And I continued developing advanced numerical models like the Global Forecast System, [or] the GFS, and the Global Ensemble Forecast System, and almost all modeling systems that NCEP operates in real time. And very recently I became the Senior Scientist for [the] Environmental Modeling Center, and I also had my stint as a development manager of the Hurricane Forecast Improvement Project, where we have the best forecast models that are used for predicting the tropical cyclones, including what’s happening currently in Florida, Hurricane Helene.

ROMAN: Yes. So I received a bachelor of science degree in geology, and then I promptly joined the Navy, which of course makes a lot of sense. But the one thing that it did give me, other than a tremendous background in and appreciation for nautical charting, is it also, in my last tour, I was the ship’s navigator. So I really gained the appreciation for charting. But I also was, as navigator, responsible for figuring out where the ship was on the surface of the Earth. And one of the intriguing things that came up was that I had to figure out where the geoid height was in the middle of the ocean as the transit satellites, which predate GPS—I’m that old—were passing overhead. And I was like, well, what’s a geoid? And why do I need to put in any type of height? I’m on the water. So fortunately for me, I was able to, when I left the Navy in active service, I went to the Ohio State University, and that’s where I received a master of science in Physical Geodesy and Surveying, and then also in…PhD in geophysics, basically. Promptly after that, I was almost immediately hired; like, within a week of graduating at the National Geodetic Survey, and I served for 15 years, actually, initially as the geoid team lead, and then moved on to be the Chief for Spatial Reference Systems Division and then later more leadership policy roles as Chief Geodesist and now as the Senior Advisor.

HOST: Dan, I think you mentioned wondering what exactly a geoid was while you were serving as the ship’s navigator. Could you unpack geodesy and geoids for us?

ROMAN: Certainly. As you can imagine, it was a novel concept to have to put in a height when you’re on the water and didn’t make sense to me at the time. Geodesy covers where you are on the surface of the Earth, and it encompasses both geometric geodesy and physical geodesy. Geometric geodesy comes from geometry. If you put down a line and you have that base line and you know that distance, and from those two endpoints you turn an angle and you look at a third point, you can figure that out. That’s basic triangular geometry. You’ve got a base. You’ve got two angles. You can define the triangle. That’s all triangulation is in geometric geodesy, only now we carry it up in a spherical geometry because now you’re dealing with satellites in orbit around the Earth, but it’s still spherical geometry. And you’re getting your positions from the geometry and your positions from the satellites. Physical geodesy is a little bit different. Physical geodesy deals with the Earth’s gravity field. Gravity is a function of the mass distributions. If you have differences in mass you have different gravity values. And the Earth has a lot of mass distributions that are a bit irregular. What that does, is it creates differences in the gravity field all around the Earth. What we’re really interested in is what we call the potential of gravity. So if you took the derivative of the geopotential, you would come up with the gravity values. So you can invert that. You can measure gravity and get these different geopotential surfaces. And the idea behind the geopotential surfaces is that’s how you describe height; the change in the geopotential surface is actual physical height change. Water flows downhill according to those geopotential heights. So we pick one, the one that best fits mean sea level, and that’s what we call the geoid. So you can’t just use G.P.S. and geometric geodesy to determine where you are. You can use it to kind of navigate. But if you’re interested in the flow of water and where water is located, then you have to understand physical geodesy and you need to understand about physical heights and the geoid. So the geoid is a specialized surface that describes ideally where the ocean is, and you can extend that under land and figure out how high your area on the land is above the ocean, or any other flowing body of water; a lake or river. Water will flow down to the ocean, but it can jump the banks and maybe go through your house on the way to the ocean. So understanding where your house is above the river or the lake or even the ocean is inherently in your interest. And that is one of the things that we try to work on at the National Geodetic Survey is to make that as accurate as possible, so that for floodplain determination, coastal inundation, coastal resilience and all those other things involve water in the land interface and where people live, that we can understand them as best as possible.

HOST: Yeah, I can see how that’s really important — especially for coastal communities and folks living near bodies of water. 

ROMAN: The age old question of, “How high is my house above that water?”

HOST: Which is an incredibly important question for engineers and community planners to be able to answer! So, mapping and charting are key components of geodesy, and Sam, I’d like to focus on some of the marine applications here. What kind of marine navigation products and services does the Office of Coast Survey shape in this field?

GREENAWAY: Sure. So the big one and the obvious one is the nautical chart. For 200 years now, the Office of Coast Survey has been responsible for making the nautical charts or the maps that ships and boats used to navigate on the waters of the United States. Those maps have gone through a number of changes. We’re in the process of phasing out the paper chart and replacing that with electronic navigational charts. What that supports; one of the big ones is commerce. Just the amount of commerce that flows internationally, and most of that is seaborne, and that seaborne trade is critically dependent on safe navigation to get in and out of ports and cross oceans. And so the charts support that. So that’s the big one. We also support making that data…making our survey data accessible to a number of other uses. The seabed mapping data we acquire is used for habitat characterization. It’s used in support of the siting of offshore infrastructure like wind farms. It’s used to support models the Coast Survey also runs of where water is moving, how water is moving, storm surge. That’s all constrained by the boundary condition at the seabed. So those are just a few of the applications that Coast Survey supports. But the big one is certainly the nautical chart for navigation.

HOST: So, sometimes I answer the National Ocean Service infobox and we get a lot of folks asking questions about the nautical charts and wanting to access the updated charts. The updated nautical charts that Sam spoke about are available at nauticalcharts.noaa.gov. Now, as you’re talking about charting and mapping, Sam, another question that we receive a lot in our infobox is about bathymetry and whether or not we can map the ocean floor from space. Could you shed some light on that, as well as what methods we actually use to map the ocean?

GREENAWAY: Bathymetry is the science of measuring how deep the ocean is. So that’s my job, figuring out how deep the ocean is. How deep is it here? How deep is it there? How deep is it everywhere? So for example, if you imagine a flat and featureless seafloor, and the ocean over that would be flat as well, and then you stick a seamount underneath that — you know, big heavy seamount — that’s actually going to pull the sea in around it in a little hill. Not very big, and you wouldn’t notice it if you’re going over it because that’s gravity. So it would seem flat to you. We can measure that and we can measure that using satellite altimetry from space. And we can invert the bathymetry. But that’s where most of that data of the ocean comes from is that inverted satellite bathymetry. So it’s gravity really that we’re looking at and inferring the Earth underneath. That’s on resolutions of tens of kilometers at best, that gravity inverted bathymetry. So to get any better, unfortunately we can’t see through the ocean. The ocean is largely opaque. You can’t see through it with light or radar or other sensors you could put on a satellite. Currently to measure the sea, we need to use sound. So we need to use sonars. We need to use equipment mounted on vessels or other platforms to put sound energy into water and bounce it off the seabed.

HOST: Thanks, Sam. Vijay, NCEP is often called the place where America’s climate and weather services begin. So how are NCEP’s forecasting and prediction models shaped by the topography and bathymetry data that we collect, like those examples that Sam mentioned?

TALLAPRAGADA: So all of these numerical models that we use are fundamentally solving physical and dynamical equations on the sphere. All of these numerical models depend on exact characterization of the landscape, including the topography, the bathymetry in the oceans, the elevations of the mountains, the slope. So we use various data sets to represent these elevations, particularly…in the ocean as well as in the atmosphere or land. Particularly for the topography, we are using information from the USGS. They are developing very advanced multi-resolution terrain elevation data. We’re also using some satellite data sets like ice, cloud and land elevation satellite. We can smooth the data to fit into our numerical models depending on at what resolution we are running our models. The reason why we need to represent these topographic aspects of our land is twofold. One, the weather phenomena can drastically change in the vicinity of these topographic elevations. If we don’t properly define these elevations in our models, that can lead to a false or erroneous propagation of waves and can influence and create errors in our forecasts. So we have to be extremely careful in [specifying] our models on how the digital elevation data is produced. We also use this data to demarcate the land surface characteristics, and that requires prescription of these data sets at a very high resolution. The currents and the tides and the rip currents and all those hazardous events like the flooding and the storm surge—as we are experiencing currently with Hurricane Helene—they all depend on accurate representation of bathymetry. Most of the ocean circulation models, including those that are used at NCEP…they apply these bathymetric data sets very precisely because some of the ocean currents are influenced by the topography of the ocean. There are other aspects of these—bathymetry—that can have influence on the ocean temperatures, the salinity and the distribution of ocean properties like the chlorophyll or biogeochemistry. So all these representations of ocean variables depend on the accurate representation of the bathymetric data.

HOST: Thanks for that insight, Vijay. So, other than satellites and sonar, what are some of NOAA’s charting and mapping capabilities and how do they inform geodesy?

GREENAWAY: We certainly fly—and this mission lives in the National Geodetic Survey—we fly lidar, which is lasers mounted on airplanes that can both map the elevations of the land as well as the depth of the water. Those sensors have gotten a lot better over the past 20 years in terms of their accuracy, the resolution, and their ability to to penetrate through seawater. Again, they don’t see very deep, but certainly in some places, particularly in areas with clear water, you can get up to 20 meters or more. And that’s a really big deal because it’s very difficult to survey those nearshore areas with traditional boats. One key connection, though, to the geodesy piece is the geodesy is, and the other datum work, is absolutely critical underpinning measuring the depth of the ocean. And that’s probably something that I didn’t appreciate when I started out in this business, and I’ve slowly grown in my appreciation for how important that is. And it’s pretty fundamental. If you’re gonna measure something, you have to start somewhere. And just getting your mind around that fact that, you know, mean sea level doesn’t exist as a physical thing. It’s something we have to define, and we have to go measure to figure out where it is. The geoid isn’t something that, you know, exists. You can’t go dig and find it written in the rock, right? It’s something, it’s an idea that we have; this is how we should structure our measurements. 

ROMAN: I joke often that mean sea level is actually not level. There’s variations due to the pressure, temperature and salinity, and what those do is they create the sea surface topography. And as you go up and down the shoreline of the East Coast of the United States, mean sea level can vary by up to a meter. Your local gauge is where you care because that’s where you live. Sam mentioned that we’re looking at satellite data. Okay, well, where’s the satellite with respect to the Earth and everything? Where is the ship? Where is the land? Where…all these different pieces of information. And how do you assimilate them together? Understanding how all of that works is important so that you can basically have that continuity of all of that data and be able to put it together. So that’s where the National Spatial Reference System, geodesy and all those components come in, is trying to integrate all these different data sets. 

HOST: Dan, I’m glad you brought up the National Spatial Reference System, or NSRS. One of the most important duties of the National Geodetic Survey is to manage NSRS, which is, excitingly, going to be updated next year. So what exactly is NSRS and what will the update involve?

ROMAN: The NSRS is the system by which we have both the geometric and the physical height models that we use to describe where things are located, how high they are above the water, all of those components. We describe where things are located. It’s the geo aspects of geospatial data. It puts the “geo” in geospatial. So the National Spatial Reference System, the intent behind it is to make sure that all of the different layers of information, be it the charting, be it the USGS elevation maps, be it the Department of Transportation’s roadmaps, be it censuses, population maps. Any type of information that would go into GIS, the idea then is each of those layers are all stapled down to the same layer, to the National Spatial Reference System. When we first defined this, the North American Datum of 1983 or NAD 83, was defined about 2.2 meters from where the actual center of the Earth is. Now, it might not seem like much. And for most applications it’s not. But if you’re going to start using the North American Datum of 1983 as your reference system, and you want to go down the road, and maybe you’re taking the GPS satellites and it’s a meter different, well, now you might be a meter to the left and you’re in oncoming traffic or a meter to the right, and you’re running up on the sidewalk. So that’s becoming significant. So to homogenize that and make things a little more consistent, what we’re going to do is we’re going to adopt what we’re calling the International Terrestrial Reference Frame of 2020. That model will be tweaked to fit to the different plates, North America, Caribbean, Pacific and the Mariana plates. And what that will do then is it will align things such that they will be within about four inches. So if you make a mistake or you’re doing something or you’re just navigating, the errors and those assumptions are fairly small; you’re only in the four inch, ten centimeter range, whereas right now they can be in the meter or so range, which might be more significant for things like autonomous vehicles. And then the other component is the physical height model. So we’re switching from the North American Vertical Datum of 1988. Again, 1988, so quite a while ago. And we’re updating that one to a North American-Pacific Geopotential Datum. And what you see is something more in the centimeter range, you know, better than an inch. So now what we’re talking about is heights that will be consistent from the East Coast to the West Coast to Hawaii, to the Mariana Islands or anyplace, because they’re all tied into the same system. It’s tied into a global system.

GREENAWAY: I’m excited to see the new NSRS come out. And then I’m really excited to see the use cases, the applications to use that…both the ability to precisely position in three dimensions and then the infrastructure to put all our data and products around that so folks can use it. One thing that’s really impressed upon me as I’ve gotten into this field is just how precise the shippers want to operate. For example, an oil tanker coming into LA Long Beach…they need to figure out how much oil they’re going to load on that ship weeks before it arrives in LA. And how much oil they can put on, that’s going to depend on how much draft they can carry, how deep the ship can be when it comes in that port. And that depends on both the detailed measurement of the depths, but also a model of the waves, and the water levels on arrival. And an extra foot is a lot of oil. And that cuts down on…if we can make this more efficient, it cuts down on emissions, it cuts down on shipping costs. And folks are clearing the seabed by not a lot. And folks are coming in under bridges on the Mississippi River, and that river level goes up and down a lot. They’re coming in under bridges with less than a couple of feet to spare.

HOST: Sam, I think you provide a great example of some of the marine use cases where this update will really matter. Consistency and continuity are so crucial for navigation, and even just thinking about these self-driving cars becoming more common — I want GPS to have the most accurate and up-to-date models to ensure that, like you said, Dan, we’re not running up on the sidewalk. Vijay — as the NSRS is set to update next year, how will NCEP’s prediction models evolve with those new survey marks and positioning data?

TALLAPRAGADA: Yeah, that’s a great question. The products that we generate, the post-processing products that are tailored for various applications, are heavily dependent on NSRS data sets. And so eventually, when the new updates are brought in, all our post-processing and product generation systems, including the unified post-processing software that we use, will be using those data sets to provide more accurate information. The environmental modeling is going to be of more importance in terms of how people depend on these models for their decision making purposes. Refining these data sets with more and more newer sets of observations and how they can be applied for our numerical modeling techniques, including use of the modern technologies like the artificial intelligence machine learning, where they can augment some of the physical and dynamical data sets that we are getting…the combination of all these, along with increased computational power, will allow us to use much higher resolution models to provide more accurate and much higher temporal spatial resolution products that people can use for various purposes with these advancements in the future. So I’m looking forward to the revised data sets from NSRS and from geodesy that we can use to improve our new liquid models in the future. I am leading this Unified Forecast System research-to-operations project, and one of the major goals that NOAA has recently taken is to unify the prediction system at NCEP across multiple time scales and spatial scales, like from minutes to seasons and from local scale to global scale. We wanted to unify all these forecast systems under one roof, and that is called the Unified Forecast System. So what this means is to integrate all these modeling systems into a unified architecture, software architecture, and use—as much as possible—common tools, common modeling systems. All these models, different components of the Earth system that they are representing, are put together in this Unified Forecast System. So all of these developments are happening in NOAA to take advantage of state-of-the-art recent technologies that can be applied for operational weather prediction.

HOST: Oh, I appreciate that insight. If you’re curious about that initiative, you can visit weather.gov/ncep to learn more. Now that we’ve covered some of the updates to geodesy, mapping and positioning within NOAA, I want to take a second to think about why these models need to be updated. What impact has climate change had on our geodetic models? And how can we understand the effects of climate change through a geodetic perspective?

TALLAPRAGADA: Excellent question. So this is something that is a hot topic, obviously, for any modeler or anybody who’s talking about the impacts; essentially what we are seeing due to climate change, how the weather is changing, how the extreme events are shaping up. So over my last two decades of experience in NOAA, we are making great progress with our [Numerical Weather Prediction] systems. At the same time, we are also seeing extremes of weather events that are either more frequent or more intense or geographically more distributed, in terms of how they are impacting the lives and property that we need to save as our mission goal. So what we are doing to adapt to these emerging changes in the climate system are to take advantage of these new data sets; as you mentioned, the geodetic data sets that are coming in is one example. We are using more modern observations from the satellites and from in-situ measurements. And we are also taking advantage of the Earth system as a whole. That requires us to focus on issues that were not particularly prominent in the past, but are becoming more and more increasingly important. For instance, the land surface characteristics and subsurface characteristics and the ocean bathymetry that I was talking about; all these are becoming more important so that we can capture these changes more precisely and prepare for the future where these extreme events need to be even more accurately predicted.

ROMAN: The ocean change is certainly the most obvious, but there are other aspects that are related to it. And it’s how you’re taking all the satellite sensors, you’re looking at changes and drought patterns and things of that nature. Those can be sensed. You actually have a number of the satellite gravity missions flying over and can detect that. So those are actually changing the Earth’s gravity field and changing the Earth’s rotation. As the polar caps kind of melt, the speed of the Earth is changing, and it’s kind of like a dancer, you know, with the arms sticking out. And then when you pull them in, they spin faster. If you stick them back out, they spin slower. So as you move mass away into the poles, you actually change the rate of spin of the Earth. So those are some of the factors that we have to determine. And it changes not by much, but it changes the rotation of the day, and, you know, the length of the day. And most of those are not going to be detectable to users. But where it comes into play is when you look at timing, the positioning, navigation and timing systems. Really, the big elephant in the room is timing. The GPS system may get out of whack, or it may not be in complete sync with the actual Earth rotation. Why does that matter? Timing is what comes into play for how power grids, how your stock trade, how any number of things happen. 

GREENAWAY: We live on a dynamic Earth. Climate change is a piece of that. But crustal motion, for example, Louisiana, the land there is subsiding quite rapidly. Global sea levels are coming up. So there’s some big change in both the shoreline of Louisiana, but also the navigational channels and the height of the levees, on the side of rivers. That’s all dynamic. And being able to access all that information in a global framework is absolutely critical to maintaining the infrastructure of the United States into the future. You got to measure this stuff. Because we— as we walk around the world, right. Where am I? Well, I’m here. Where are you? You’re right there. What time is it? Well, I look at my watch, but the support to make that all connect together, that fundamental geospatial framework, it takes a lot of work. And there’s a lot of really cool stuff when you dig into it. Measuring gravity, that’s cool stuff. Putting gravimeters into planes and flying them all over the place. And just getting into these nerdy details of how we provide that spatial infrastructure, it’s neat, but it’s fundamental to built infrastructure, the built and lived infrastructure of the United States.

HOST: 100%. Thanks to the three of you for shining a light behind the curtain on this fundamental science. And I want to thank each of you for joining us on Planet NOAA today. 

[Did You NOAA theme music plays]

HOST: I’m back with Tara Garwood. It sounds like people have followed some pretty unique paths into the field of geodesy — particularly some of those women in 1967. When the ESSA staffer shared that the convenience of the bus stop at the door of the Commerce Department launched one career, what on Earth were they talking about?

GARWOOD: Let’s take a listen!

SCHWARTZ: Fate, in the guise of a convenient bus stop on a rainy day, led Helen Stettner into geodesy. Having arrived for a job interview in another government agency too late to see the proper person, between showers she dashed out to catch a bus, which stopped next at the door of the Commerce Department. Hoping someone in the Commerce Department was looking for someone with her qualifications—B.A. in mathematics and chemistry from Brooklyn College—she alighted from the bus and ran inside. That day in 1948 she became part of the Triangulation Branch. While all became geodesists for different reasons, on this there is mutual agreement; their work is fascinating, and— best of all—very satisfying.

GARWOOD: Well, that’s one way to do it!

HOST: What about Juliana Blackwell? Did she follow an equally roundabout path to geodesy?

GARWOOD: I’ll let her tell it! Here’s how Juliana’s passion for geodesy ignited – right as GPS was becoming fully operational, no less: 

BLACKWELL: In January of 1990, I headed off to Newport News for NOAA officer training. I went to my captain at the time, the commanding officer of the ship.  I was talking to him about my next assignments that I was interested in.  The one that caught my eye was Geodetic Survey. Because we had GPS on Ferrel. I just didn’t really know a whole lot about it.  We weren’t supposed to be using it for navigation on the Ferrel because it was still not fully operational.  It was a black box kind of thing.  But then I got this magazine, and I started reading about it.  I’m like, “This is so cool.” This is revolutionizing positioning, right?  It’s got surveying, it’s got math; everybody wants to know where they are.  It was one of the next little steps in this career thing that just was like, “This is what I want to do.”  After learning about the Geodetic Survey, I went back and filled out my “dream sheet,” the list of assignments that I wanted to do. I applied for the position that was basically a field assignment to go, again, probably to my mother’s dismay, traveling across the country, wherever they wanted to send me to collect survey data and learn about the different geodetic techniques for surveying. And so GPS was one of them; leveling, taking gravity measurements, and doing other kinds of line of sight measurements…all part of my hands-on experience that I had for eighteen months as my second assignment as a NOAA Corps officer. But with GPS, it was a new technique to use. With the new equipment, the processing of the data, the setting up of things, and the fact that the GPS constellation wasn’t fully complete yet; there were a lot of challenges with when the best times were to go out and survey. Sometimes, it was in the middle of the night, and you had to survey for at least five and a half hours on a point in order to get enough data. So, there are times you wake up in the middle of the night to go out and set up on a point to collect the data because that’s when the satellites were in the right alignment to get the best data possible. It was a great opportunity; I never…starting out in the NOAA Corps as an ensign, I never ever would have imagined that I would become a director of an office such as the National Geodetic Survey. I still can’t believe it, to this day, that it all happened. 

GARWOOD: So, the next time you use your GPS, remember, Juliana and co were crouching in dark fields at 4 in the morning to make that drive to Grandma’s on Thanksgiving a little easier to navigate! We’ll be back with more right after this.

[Leadership Corner theme music plays]

HOST: Let’s take a look at our planet through NOAA’s eyes in the sky — our satellites! I’m delighted to have Dr. Stephen Volz joining us in the Leadership Corner today. With over 3 decades of experience in aerospace under his belt, Dr. Volz serves as the Assistant Administrator for NOAA’s Satellite and Information Service, or NESDIS. He helps define the space and information architecture for NOAA, and guides the U.S. approach to future civil space observations. Steve, we’re thrilled to be speaking with you today!

DR. STEPHEN VOLZ: Thank you, Symone. It’s a real pleasure to be here as well. I’m looking forward to a great conversation. 

HOST: Steve, can you talk to us a little bit about what sparked your interest in aerospace? 

VOLZ: It started when I was growing up. My father was an aerospace engineer. Graduated college in the 40s and worked in wind tunnels and airplane design and aerospace in the 50s and 60s. Actually was a civilian working for the U.S. Air Force for many years. So he would bring home airplane models and pictures of rockets, and when Apollo was flying, he would get access to high resolution Apollo pictures that he’d bring home. And those were all very exciting. So I grew up with that imagery and that vision around me. And if you remember the 60s and the early 70s, it’s Rocket Man and Space Ghost and Lost in Space. So I grew up during that era, and I just took to it right away. 

HOST: Not many kids can say they were getting the real-time Apollo imagery to go alongside their space comics! I think it’s no surprise that you found your way to NESDIS. Can you talk to me a bit about the origins of NESDIS, and some of its earliest satellite programs?

VOLZ: So, some of the first flights of rockets in the early 60s were looking at the Earth. And as I’ve come into this career in this job, I’ve seen more of the early work. Recognizing the value of observing the Earth from space would have good benefit for humanity, for people on the planet, particularly weather. So, as early as the early 60s, NASA and what was then ESSA were launching satellites; TIROS, the Earth observing satellite looking down at the Earth and seeing clouds and weather patterns on a hemispherical basis. And that led to a series of satellites in the 60s observing the Earth and actually doing initial Earth observations for weather forecasting and weather. And that led to the creation of NOAA during the environmental explosion, if you will, and the Earth Day in 1970, and a bunch of other things. NOAA was created from separate organizations that were already existing in the federal government, including ESSA, to be responsible for the science, service and stewardship role we have, one of which was observing the Earth from space for awareness of weather and supporting the weather enterprise that [the] National Weather Service was responsible for. So the first of NESDIS was the creation of NOAA back in, I think, ‘72. And you asked earlier about the earlier innovations of NESDIS. Really what we have learned to do over the past 40 years with multiple generations of satellites is really begin with the service end in mind. And to understand what the communities and the services need in terms of information and observations, so that we actually drive our observations based on end use. Our research is driven by a service objective in the end. And that’s really, I think, one of the most compelling elements of NOAA’s mission. 

HOST: 100%. And it’s not just the public and other agencies using those services – it’s NOAA’s many line offices that rely on the data coming out of NESDIS to really further our science. And so, as the NOAA lead for Earth observations from space, you’re right at the frontier of some of our most technologically advanced—and just purely interesting—ways of capturing and communicating environmental information to the public. So what kind of interactive imagery does NESDIS provide to the nation?

VOLZ: So I like the way you phrase that question in terms of imagery. And the reason why is that humans are highly optimized to take visual imagery or imagery as one of the most important inputs that we get. Whether it’s plains animals trying to avoid lions, seeing movement at a distance is really important to us. So our brains are keyed on activity and movement and dynamics in the imagery. So one of the biggest changes that we’ve had in the past few years, with our most recent satellite launch, has been when you take a picture of the planet from geostationary orbit, which is 22,000 miles up, it takes a long time to take a good picture. You got, you know, long exposures. You want to get good resolution. So until recently, we would be able to take pictures every half hour, every hour. And you could see the movement of clouds and dynamics and that kind of time frame. And those are still images. And you can look at a still image and you get a lot of information from it, especially if you’re a scientist or a specialist. But it’s still a “still.” It’s static. The innovations with the most recent program we launched, GOES-R, first launched in 2016, rapidly increased the speed of our cameras onboard. So, based on a lot of technology advances—high resolution pixel arrays, much faster electronics—so that we are now able to scan large portions of the regions every 30 seconds. So instead of a snapshot every ten minutes, which might get this kind of stuttering picture moving, we’re getting sometimes 30 second updates on dynamic events, and that really has just exploded the use and usability of public domain for use of our imagery. You probably see that on the evening news. Or when you see hurricanes, you see the swirling clouds, not just the big cloud of a hurricane, which might be 1000 km across, but with the high camera resolution, you can zoom in and see little eddies and swirls in there, which might be ten kilometers across. And you can see the dynamic events of lightning striking in real, near-real time. A great example of this was, Hurricane Harvey was a massive event. It was the biggest rain event in history to that point, with a very clearly discernible eye, which is the swirling center point where it’s actually really still air in the middle of the hurricane. And as it was making landfall in real time, we were able to pinpoint the location of the eye with sufficient detail so that emergency managers who were trying to evacuate people along the Gulf Coast in Texas…we were able to tell them, “In ten minutes, the east part of Galveston will be in the eye and open for 20 minutes as the eye transits across Galveston.” And managers in the city then were able to sortie their people, knowing that the eye was going to be there in a few minutes and was going to be back, you know, the wall was coming in 15 minutes in the other direction. So during that period of time, they were actually…going out, help some people and bring them back into shelters before the other side of the eyewall came and hit them.

HOST: Honestly, listening to you share that makes me really proud to know that these satellites, and the folks working hard to communicate this information on the ground, have actually saved lives when it comes to severe weather events. I want to take a temp check on the GOES–R satellites that you mentioned, which our listeners may remember from previous episodes. Earlier this year, upon reaching geostationary orbit, the new GOES-U satellite was renamed GOES-19. So let’s check in on GOES-19 – can you tell us what role it plays as part of the GOES-R series and what it’s up to so far?

VOLZ: Sure. Great question. And we’ve already talked somewhat about the value of the GOES system. So GOES-19 is sitting roughly over the center of the US. It launched in June and is…so far the instruments are slowly being turned on it. We have something called outgassing. When you get into space you have lots of moisture and other stuff in your spacecraft and your blankets. We have to gas all that out. When we get into space, we get it pumped out and it dries out. Basically, if you were to open up your telescope and you hadn’t done that, the vapor, the water that’s in your blankets might all condense on your mirrors. If you’ve ever been in a bathroom without the vent fan working, you know it’s hard to look at a mirror that’s covered with humidity. So we make very sure that before we open up the telescope that everything is dry. And that’s where we’ve been going through an outgassing and checkout period right now on GOES-19. We, just this week or last week, got the first image from the Advanced Baseline Imager on GOES-19 and it looks beautiful. And there’s another half a dozen instruments on there. There’s a lightning mapper, several solar observation instruments. And one thing that’s very exciting is [it’s] the first time we’ve launched a coronagraph. Now GOES looks at the Earth. But a lot of what happens on the Earth is affected by the sun. We also look at the sun. We monitor solar storms. We look particularly for solar flares, or what we call coronal mass ejections, which are big storms on the sun which spew out billions of tons of protons and the like, which, most of the time, just go into space. But if we happen to be in the line of trajectory, they can hit our magnetic field, our Earth field, and cause significant solar storms, which affects satellites in space. Magnetic fields can actually affect our power grid. So, the coronagraph that we’re launching on GOES-19 is the first one that we’ve launched by NOAA, first operational coronagraph. And it will be significantly improving our ability to monitor and detect the emission of major solar storms coming from the sun. It takes about 6 to 8 months to check out all the systems, to know that everything’s working and to make sure we have all the processes, procedures lined up correctly. And then when that happens and is done, we’ll move GOES-19 to the East Coast, where it will take up its role as the GOES-East, operating over the Atlantic. And what’s currently in GOES-East, which is GOES-16, will go into a backup mode.

HOST: I’m glad you brought up solar storms. Folks, if you listen to Episode 2 of the Planet NOAA Podcast, you can learn more about the GOES-R series and about coronal mass ejections. So since that episode aired, we are now on the brink of improved monitoring of solar storms with the GOES-19 satellite, so we can be getting those warnings out faster than ever if we’re in the line of trajectory. Steve, I can tell from our conversation and the way you explain the intricacies of these programs and satellite tech that you’re really passionate about the work you do. So can you tell me, what’s your favorite part about working in space, so to speak?

VOLZ: Well, part of it goes back to when I grew up in the 60’s and 70’s, is, I always wanted to be an astronaut. And I actually applied several times; never got there. I think everybody who grew up during my period wanted to be an astronaut. But what that left me with is, I’m used to seeing the Earth from space. What I really like about working in space is the idea that all of these parts are connected. You know, you always hear the old, “You can’t see national lines from space.” Well, actually you can. You can see one country has a good economy, another one has a poor economy. You see a borderline where there’s lights on one side and not on the other at night. Deforestation in one region and not in another. So it is not true that you can’t see the political boundaries in space. They’re highlighted through environmental boundaries and economic growth and actually human value, human life, quality of life, boundaries in space. So my favorite part of working this and knowing that as a provider of information and ideally of understanding is that we can help provide information that leads to good or better solutions about how to mitigate some of the worst impacts of poor decisions, or just the worst impacts, the consequences of environmental effects as they occur. It’s one thing to say, “They’re happening. Watch out.” That’s important. But it’s even better if we could say they’re happening because of these three things that we did over the past year or two years. And if we do it differently, it won’t happen in the same way. That’s really the best part about this is that we’re having an impact, I hope, and we’re providing information that allows everybody to live better in the world that we are in. 

HOST: I really love that perspective. Space observations lend themselves beyond pure science – they reflect humanity. Being able to see those boundaries and divisions from space is such a catalyst for change. Steve, thanks again for joining us today.

[Did You NOAA theme music plays]

HOST: Tara, we’ve gotten to chat a lot about the National Spatial Reference System today. Was Juliana involved in that work as well?

GARWOOD: Yes! Juliana played a big role in NGS’ Height Modernization research…at its height! The height modernization program helped GPS more accurately determine heights in different areas, which assisted local planners and engineers in answering questions like, “Which way is water going to flow?” or, “How high would we need to build this road or bridge to ensure that there’s enough clearance?” This initiative helped NGS to update the National Spatial Reference System under Juliana’s leadership, using both height and gravity research modernization tools:

BLACKWELL: The Height Modernization Program really became the foundation for the National Spatial Reference System modernization, which is really what I’m most proud of during my career and my directorship was…the basis for the improved geoid model that’s gonna support the improved vertical or geopotential data required airborne gravity collection over the entire United States and its territories. So we completed that at the end of 2023. Being able to get all of that airborne gravity collected so that we could have an improved model everywhere, not just in places that were easy to get to or funded by some other entity, but the fact that, in a sense, it’s inclusive and fair. That’s really important for anything having to do with flooding, surveying, building roads, buildings, homes; measuring changes over time to see how the Earth is changing. The National Geodetic Survey can’t change what’s really happening, but we can at least measure and monitor it and provide that information so others can use it to the best of their abilities to make sure that they have the best information about the actual heights of places and survey marks used for development and analysis and monitoring of change over time, regardless of what the cause is, whether it’s manmade or natural.

HOST: I think Juliana’s last point is such a great one. We can’t control the geodetic events that come with living on a dynamic planet, but we can certainly measure their impacts. 

GARWOOD: Exactly. If you’d like to listen to more of Juliana’s chat with the NOAA Heritage Oral History project as part of the NOAA Voices initiative, you can visit voices.nmfs.noaa.gov and search “NOAA Heritage Oral History Project.” And you can read that ESSA article at noaa.gov/heritage/friday-finds!

[Planet NOAA theme music plays]

HOST: Thanks for joining us on Planet NOAA, where we prepare people for tomorrow’s planet, today.  Tune in next month to learn more about the mysteries of severe weather, or catch up on episodes anytime on your podcast player of choice.