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Taking the Temperature of Earth

Season 1Episode 213Sep 17, 2021

Kerry Cawse-Nicholson from NASA’s Jet Propulsion Laboratory describes the ECOSTRESS experiment aboard the space station that is looking at the Earth to map temperature in plants, urban areas, wildfires and more. HWHAP Episode 213.

Taking the Temperature of Earth

Taking the Temperature of Earth

If you’re fascinated by the idea of humans traveling through space and curious about how that all works, you’ve come to the right place.

“Houston We Have a Podcast” is the official podcast of the NASA Johnson Space Center from Houston, Texas, home for NASA’s astronauts and Mission Control Center. Listen to the brightest minds of America’s space agency – astronauts, engineers, scientists and program leaders – discuss exciting topics in engineering, science and technology, sharing their personal stories and expertise on every aspect of human spaceflight. Learn more about how the work being done will help send humans forward to the Moon and on to Mars in the Artemis program.

On Episode 213, Kerry Cawse-Nicholson from NASA’s Jet Propulsion Laboratory describes the ECOSTRESS experiment aboard the space station that is looking at the Earth to map temperature in plants, urban areas, wildfires and more. This episode was recorded on August 17, 2021.

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Gary Jordan (Host): Houston, we have a podcast! Welcome to the official podcast of the NASA Johnson Space Center, Episode 213, “Taking the Temperature of Earth.” I’m Gary Jordan, and I’ll be your host today. On this podcast, we bring in the experts, scientists, engineers, and astronauts, all to let you know what’s going on in the world of human spaceflight. The International Space Station is a wonderful place to conduct microgravity science, and it’s a hotspot for a lot of experiments because of this capability. But the space station also allows us a great vantage point to look down at our own home planet. Pair that view with a very capable international laboratory with lots of power and data available, and the possibilities soar…or orbit, I guess. One experiment on board station right now is helping to see how effectively plants are using water across the planet. The experiment is called ECOSTRESS, which is, of course, an acronym, for ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station. Joining us from the Jet Propulsion Laboratory is Kerry Cawse-Nicholson, who describes more about this experiment and how it’s helping to understand how efficiently we’re using our water across different biomes and factoring in climate change; also the way it’s helping with urban areas and volcanos, and even looking at wildfires across the western United States. So, let’s explore Earth science taking place right now on board the International Space Station. Enjoy.

[ Music]

Host: Kerry Cawse-Nicholson. Thanks so much for coming on Houston We Have a Podcast today.

Kerry Cawse-Nicholson: Thank you so much for having me. I’m so glad to be here.

Host: All right. We are going to be talking about this great experiment called ECOSTRESS. It’s looking down at the Earth from the International Space Station and studying some very cool things. What’s interesting is that this is, we can call it Earth science, but your background is in computational and applied mathematics, and I think there’s a lot of data coming in here from this experiment, so I want to understand a little bit more about you, what helped you to prepare for analyzing all the data that’s coming in from ECOSTRESS? So, Kerry, please tell us about yourself.

Kerry Cawse-Nicholson: As you said, I studied applied math, and the really great thing about applied math is that you can use it for just about anything. And so, in this case, I use it to figure out exactly what’s inside an image, turning digital numbers that we receive into some useful information. So, can we translate our image into crop stress? Can we find really hot fires? Can we study urban heat? All of this requires looking at the numbers within the image itself and its position in space, and turning that into some kind of information. And so, that’s where my applied math background really, really comes in handy. And so, a lot of what I do is just looking at really cool images taken from space.

Host: [Laughter] So, have you done this before? What’s some of your previous work that helped you to prepare for ECOSTRESS?

Kerry Cawse-Nicholson: Yeah, I actually did my Ph.D. in an applied math topic where the application was in imagery and using mathematics to, to define the contents of imagery. And so I started off with that background, and I have worked with all kinds of imagery over the South African savannas, over the forests of New England, and I even worked as a consultant in the mining industry for a while. And so, I bounced around in a lot of different application areas before I landed up at JPL (Jet Propulsion Laboratory), but working with this kind of imagery is really rewarding because there’s that real human impact. You know, people are actually able to use this imagery to really understand their environment and utilize their resources effectively.

Host: Perfect, and Kerry, that’s exactly what I want to get into today, is understanding exactly what this experiment is and what you’re looking at. Why don’t we start with the problem: what is it exactly that’s going on that made you guys think, hey, we should make an experiment that is studying these things? So, what’s happening on the Earth?

Kerry Cawse-Nicholson: So, as you know, we have rising temperatures. We have drought, especially in the western U.S., we have a really severe drought, and plants respond to that water and heat stress sometimes in subtle ways that we’re really trying to understand. So, plants, during the normal course of the day, they have very small holes on their leaves like pores, they’re called stomata, and they open their stomata to take up carbon to photosynthesize, but as they do so they also lose some water through a process called transpiration. When they reach a point where they feel like it’s getting too hot, they’re starting to lose too much water, some plants have a strategy where they actually close those holes. They close their stomata, and they can preserve water, but of course that comes at a cost because then they can no longer photosynthesize. And so these plants are continually trying to find a balance between saving water and maximizing their productivity, and that’s something that we’re trying to understand. Because when those pores remain closed for too long, those plants actually start to heat up, and it’s those very, very, very tiny temperature changes that we’re measuring from ECOSTRESS, and we can detect that indicator of plant stress before the plant visibly turns brown. And so this helps us understand how plants are coping in the face of heat and water stress, and how that behavior changes throughout the day.

Host: So, give us an idea of what these subtle temperature changes are. What are we talking about here: is it a matter of degrees or less? What are these changes that you’re measuring?

Kerry Cawse-Nicholson: Well, that’s where it actually becomes quite a complicated problem, because the land behind the plant itself is changing over multiple degrees, you know, moving throughout the course of the day and through different seasons. And so that change in temperature of the plant itself is very subtle, and so we actually pull in quite a few different datasets to understand exactly what’s going on. So it’s quite a complex modelling problem that takes in land surface temperature as a primary input, but we also have to understand something about the weather, the wind, the humidity, the air, the way that the vegetation looks on the ground, and we take all of that into a complex model, which in essence spits out an estimate of plant stress, something called evapotranspiration.

Host: So, in terms of the farmers themselves, when a plant is stressed, how does a farmer have to change the way that they are watering their crops?

Kerry Cawse-Nicholson: Oh, so this is interesting because there are quite a few different things that a farmer can do, and of course they will really on their own expertise in their area. But if they work out that a particular field is stressed, they can change the amount of water that they give to the plant. They can also change the time at which they water the plant. And so ECOSTRESS, being on the International Space Station, has a really unique feature because every time the International Space Station passes over us, it comes over at a different time of day. And so ECOSTRESS is able to make measurements of all these different times of day. So, if you’re able to say, you know, this field was stressed in the afternoon but not in the morning, you can start working out the best strategy for taking care of these plants.

Host: I guess — that’s sort of what we’re going to get into, right, with ECOSTRESS is it’s got that perspective of, you know, we’re talking about the greater United States, I believe, is what you guys are analyzing, but that orbit puts you, lets you gather data at several points during the day. It provides a really great perspective that, that low-Earth orbit seems to be a great place to be.

Kerry Cawse-Nicholson: Oh, yeah, for sure. And, you know, the original proposal was to focus on the United States and a few target sites elsewhere, but since we’ve launched we were actually able to acquire much, much more than we anticipated. So, now, we acquire almost everywhere over land within the parameters of the ISS orbit.

Host: Oh, that’s fantastic, because the ISS orbit covers, I believe, 90% of the populated world.

Kerry Cawse-Nicholson: Yeah, exactly.

Host: Oh, that’s a lot of data. So, OK, you’re gathering all this data. I want to understand better, more about the problem itself. So, you said, the way you kicked it off when I said what is the problem here, you mentioned that the Earth is heating up. So, what does climate change have to do with the way you are modeling your, this data coming in over time? How does climate change, or are you measuring climate change? What, what is happening there?

Kerry Cawse-Nicholson: So, because ECOSTRESS has been in orbit for just over three years now, that’s not long enough to look at a long-term time series of change in climate, but a change in climate is really what drove the need for this experiment. And so, we don’t have the long-term measurements to measure climate itself, but what we are measuring is the climate change impact. And so, we use ECOSTRESS to study these droughts, we study the plant strategies, how plants are trying year on year to account for these changes, and somewhat aside from the main goal of the project we’re also able to use thermal measurements to measure the change in temperatures in cities, and of wildfires. And so, these are all the climate change impacts that we’re really concerned about, and that was really the motivation for launching a mission like this.

Host: Very good. Now, one thing I saw when looking up what ECOSTRESS is studying, is something called diurnal vegetation water stress. You may have already addressed this, but just for my own education, what exactly is that?

Kerry Cawse-Nicholson: So, that’s, in essence, the way that a plant behaves throughout the course of the day. So, typically, plants are relatively dormant at night, and then as the sun rises, they start evapotranspiring. In other words, they open their stomata, they start taking up carbon, they start releasing a little bit of water. And that starts relatively small, and the productivity ramps up until the middle of the day you have your highest ET, and then it’ll start to decline until the evening. So, you typically have this sort of parabolic or sinusoidal shape of evapotranspiration, which we abbreviate ET. And deviation from that is what we look for as a measure of plant stress. So, as ET reaches its peak, does it suddenly drop down because those stomata have shut down? And then perhaps they open up again later in the afternoon when it’s cooler? And so, understanding that diurnal pattern, the pattern of plant use throughout the day, is really important in both the science of understanding how vegetation actually works, and this is really interesting because we’ve studied this at field sites, but those are, you know, individual towers, or individual trees that are quite sparsely spread out, and so, the idea of being able to do this over wide areas but still at quite fine spatial resolution is something that hasn’t been done before. So, that makes that a really unique experiment.

Host: Very awesome. Now, let’s go into low-Earth orbit. Let’s talk about ECOSTRESS. Now, if you were to paint us an image of what this facility looks like on orbit, where it is, that sort of thing, how would you describe ECOSTRESS?

Kerry Cawse-Nicholson: So, ECOSTRESS looks somewhat like your refrigerator, [laughter] a little bit. Surprising perhaps, but it is a giant rectangular box that’s plugged into the outside of the ISS, somewhat like a giant USB drive. It’s plugged to a facility called the JEM-EF (Japan Experiment Module-Exposure Facility), which is actually a Japanese experiment module, and it has a number of instruments mounted on it, making observations both of Earth and on space. And it’s really useful to be plugged into this external facility for a number of reasons. So, first of all, because they are able to pump cooling fluid throughout the module itself, which helps us to keep our instrument cold, our instrument needs to be kept really, really cold so that we can be accurate in measuring the temperatures on the ground, and also, the ISS gives us this path of communication to send our data down to the ground.

Host: That’s right. So, you’re using the, it sounds like you’re using the, the energy of the space station and possibly even the coolant — or no, the coolant is inside of your own experiment, temperature, is what it’s doing, right? So, that’s very important on the facility itself. But you’re right, we have the space network and all these Tracking and Data Relay Satellites. You need a lot of data coming down that it’s gathering. And so, so what exactly is, I guess it’s just, is it looking down at the planet, how exactly is it measuring the temperature and getting that information to you guys for analysis?

Kerry Cawse-Nicholson: So, the energy from the Earth is both reflected sunlight traveling towards our instrument, but there’s also thermal energy, which we can’t actually see. And so, if you imagine putting on night vision googles, that gives you an indication of sort of thermal energy that might come off of a person or an animal, and this is what we measure in a much greater sense coming off the surface of the Earth. It’s that thermal energy, and we measure that thermal energy in a few different wavelengths. And understanding that energy gives us an indication both of what the ground or the surface itself is made of and how hot it is, and we have to disentangle those two along with the effects of the atmosphere to get to how hot something is. And so, as an example, if you were looking down at your floor and you’re shining a warm light on it, and you have some water on your floor, and you have some metal on your floor, that metal is actually interacting differently with the energy than the wood, and each of them are returning a response, or in this case a radiance, that’s indicative of both their material and that sort of made of chemical vibrations that’s affecting the energy as well as the temperature it’s at. And so, these are both useful. So, working out the emissivity of the surface can tell us a lot about mineral types or whether we’re looking at vegetated areas or cities or water, and then the temperature is obviously useful for detecting that plant stress but also, detecting heat levels in cities and fires.

Host: Wonderful. Lots of sensors, lots of information coming up. Now, how about the actual design of ECOSTRESS, when you guys were putting together all the facility together and getting ready to ship it up to the International Space Station, I wonder if you were a part of that process and what it was like to see your experiment, all this hard work and all these delicate sensors going up to the International Space Station for installation. You know, what was that like to actually, you know, after all that hard work of putting this thing together, to see it actually on this giant orbiting laboratory?

Kerry Cawse-Nicholson: Yes, I actually joined the project just before the launch, and so —

Host: OK.

Kerry Cawse-Nicholson:…I wasn’t involved in building the instrument. There were a lot of really talented engineers at JPL who put it together, but I was present at the launch. And oh, my goodness, it was just the most incredible experience. It was the only launch that I’ve attended, and we went down to Florida, and it was this launch just about as the Sun was rising. And so, we were sitting in the dark, and suddenly you just feel this huge vibration as the rocket lifts off. It was on a SpaceX Falcon 9 rocket. And seeing it in the sky that was darkened and just starting to turn pink and purple was just amazing. And you know, after it had reached orbit, the Sun was rising; the sky was pink and purple; and there was this trail of smoke in the sky. And you know, we were launched in the Dragon trunk on the Falcon 9 rocket, and the joke was that the smoke that we could see looked like it was something that was breathed out by a dragon. And so, I actually have the photograph of it framed and on a wall in my room because it was just such an incredible sight. So, once it was in orbit, you know, the trunk was linked to the ISS, and there were a series of robotic arms that picked it up and moved it to its external facility outside of the ISS, and it was this very, very long and slow process—it took about a day to get the instrument outside of the Dragon trunk and into its final spot, where it is now. And it was this nerve-racking experience where you’re seeing this robotic arm dangling your experiment over the Earth, getting it to where it needs to be. And you’re thinking the whole time, don’t drop it, but you know, of course these robotic arms are very well set up, and it’s something that they’ve done many times. But it was just an incredible experience to watch that. And then to get our first data down and start looking at what we’re seeing wasn’t what we expected. So, amazing.

Host: I mean everything you just said, I was trying to live vicariously through you. It just sounds so special. You know, it’s one thing to see a launch, and launches are beautiful, but to know that it’s your experiment in the trunk of that Dragon, right?

Kerry Cawse-Nicholson: Yes.

Host: And that’s the one that’s going up. It has to be, it’s like a very personal launch to you. And all of these different moments you’re talking about, the robotic arm moving, and even gathering the first data. So, tell me about that. Whenever you saw the data for the first time, what were the expectations going in, and what, you know, what was the actual data that was being delivered?

Kerry Cawse-Nicholson: Yeah, so, you know, we, we received our very first data, and I was trying to look at it before we had worked out the geolocation. So, before we really knew where we were in space, and so we could figure out where the ISS was, and we could look at the digital numbers we produced, and we were still in the process of putting it, the image, exactly on a map. And so, I was looking at it by eye, trying to figure out what I was looking at, and it was the Nile [River] just coincidentally providing this perfect geolocation to help me work out exactly where I was and what I was looking at. And so, that was really just lucky that we happened to pass over such a unique landmark. And so, I was looking at Egypt, and you could see the temperatures of the sand compared to the water and the vegetation around it, and it was really showing us temperatures, and that was something that was really exciting to see: it really looks like an image, these look like realistic temperatures. And shortly after that, we were able to pass over some of our validation facilities. So, we have some buoys in lakes, in Lake Tahoe, in the Salton Sea, that are actually measuring the energy that’s radiating off the surface of the water, and we can compare that to the energy measurements that we make from ECOSTRESS and just make sure that what we’re measuring is very accurate. And when we did that first validation study, it was, it was accurate, and so, that sense of satisfaction, knowing that it works, it all came together, is just really, really exciting. And of course, we still do that experiment fairly regularly, just making sure that the sensor is still working as it should. But thankfully it has been and so we’re making these really, really accurate temperature measurements.

Host: You sound so passionate about all these, when the data comes in, you just sound so excited, especially in that beginning. And I want to get a sense, Kerry, of your day-to-day, of exactly, you know, when the data is coming in, what exactly are you looking at and how are you translating that into data? So, take us through the life of, you know, you and your team in the lab and how you’re working with the data that’s coming in.

Kerry Cawse-Nicholson: Sure. So, they’re sort of two streams. So, on one hand, I have my long-term research projects, and so, that’s something that over time I’m gathering data to study. And one of my research projects is understanding that diurnal cycle of evapotranspiration like we talked about, understanding how that changes across different landscapes. And so, that’s continually gathering data acquired at different times of day to see how we can combine those datasets, compare them to ground stations and turn that into a better understanding of vegetation strategy. And then on the other hand, we’ve got the sort of immediate events that we need to be handling. And so, last week in particular was all about fires. You know, the Dixie fire is something that we’ve been monitoring, and there are plenty of others as well. And so, I have an algorithm that automatically detects fire in images, and so I spend a lot of time looking at these images where we detect fires, working out how that fire is growing, and showing if there is anything we can do with that data. And so, one of my colleagues, Christine Lee, is working with the Pacific Northwest National Lab, and they’re working with the U.S. Forest Service to actually take in these heat maps of the fires to work out exactly where the fire front is, and to determine where best to allocate their resources. And so we’re continually looking at these images as they’re coming in: have we learned something new, how far has the fire spread, is there anything we can do? So, there’s that aspect. There’s also, you know, monitoring the ongoing drought, how are these images looking? How can this be used in the agricultural community and the water resource management community? And so, it’s an interplay between the long-term research goals and the short-term applications goals. And so, typically, I spend a lot of time just looking at imagery on my computer, saying what does this look like, how can I best use this data? And then I spend a lot of time coding to pull information out of the data, and that’s where my applied math background comes in. So, how can we find patterns in what we’re seeing with different plant types, how can we find patterns in the spread of the drought or the growth of the fire? So, I spend a lot of time on the computer.

Host: But it sounds, I mean what you’re doing is absolutely fascinating, even the long-term data that you’re collecting, it’s going to have, you’re talking about, you know, helping plants around the world to grow, and understanding how the environment changing, you know, how we can use water more efficiently, it sounds like. But these short-term goals, and you talked about that in the beginning, and I think that’s absolutely fascinating. You talked about these wildfires, you talked about, you’re looking at urban areas, and it sounds like what you’re doing is you’re creating unique algorithms to go look at that, and you’re working with a team on, once you have the data being pulled in, what is the data telling you, and how can we make decisions on that, and for the fires, that sounds absolutely fascinating, because it sounds like what you’re doing is you’re helping with strategy on how to best deal with the fire, if there’s something, how can we help to mitigate this fire, and that’s really what your team is bringing in the short term, and that’s one of the applications that maybe wasn’t part of your long-term research but is something that you find it, there’s so much value to this experiment, to ECOSTRESS, that you can help out in various other ways that maybe wasn’t part of your initial study.

Kerry Cawse-Nicholson: Yes, you’re absolutely right.

Host: So how —

Kerry Cawse-Nicholson: And it’s been particularly important now just given the state of the fires in California —

Host: Yeah.

Kerry Cawse-Nicholson: — and the heat waves and the drought, it’s all just become really important right now, and so it was especially well timed, and will be in the future as well.

Host: Yeah, now, now, the other one you said was urban areas. Now, how does that translate? I guess you’re watching the temperature in these urban areas and how that’s changing over time, but what are you noticing now, and what are those short-term strategies that you’re delivering to say, hey, here’s what’s going on in the urban areas, and here’s something we can maybe do to help?

Kerry Cawse-Nicholson: Yeah. So, one of my other colleagues, Glynn Hulley, has been working closely with Los Angeles County on some of their mitigation strategies, and it’s really interesting, you know, the climate crisis is really providing a great opportunity for innovation, and this is something that we’re seeing around the world, but here locally, there are a few initiatives. One of them is to actually paint the surface of roads with something that doesn’t retain and reflect that heat out to the surrounding community. And so, there was an experiment recently where they took a particular road as a test case, they painted it, and they looked at ECOSTRESS imagery before and after they had done the experiment, and the impact was actually quite amazing because the temperature decreased several degrees, not just on the road itself but even in the surrounding neighborhood. And so, ECOSTRESS is useful to help actually monitor those mitigation strategies, see how effective they are. There are other studies on the effect of trees in urban landscapes and their cooling ability, and there have been other initiatives somewhat similar in painting roofs or changing what roof tiles are made out of in the same way to kind of prevent that heat from radiating throughout the community. And there’s also been some work on understanding vulnerable communities by combining this heat data with some socioeconomic data and understanding where people in L.A. and in other big cities might be at the highest risk of heat-related illness.

Host: Very interesting. I know Houston itself has implemented this strategy, you mentioned trees as one of them and how trees are helping, and so everybody, me, myself included, anyone that has a house is required to have a certain number of trees in the front just to help, you know, be a part of the community and help to reduce heat around. And so, it would interesting to see the ECOSTRESS data on some of the communities that have larger trees and how that impact changes. And that’s one of the values of ECOSTRESS. I think another one that I saw, at least on the website, was volcanos. Now, how is ECOSTRESS monitoring volcanos?

Kerry Cawse-Nicholson: Yeah, so ECOSTRESS is particularly interesting for volcanos for a number of reasons. First of all, it’s because each pixel size is about the size of a football field, so relatively small compared to some of our larger polar-orbiting satellites. And so, it’s able to detect much smaller lava flow, and also it comes over every one to three days depending on the ISS orbit. And so, we can get quite regular check-ins on how that lava is moving. So, of course, we measure the heat of the lava flows, but we can also measure some of the sulfur dioxide gas that is coming out of the volcano. And so, these gaseous emissions are important for understanding volcanic activity, understanding impact to the surrounding environment, and understanding how that gas is spread in the air through quite wide areas. And being able to return that data quickly to various volcanic observatories enables a faster response, understanding, you know, how the lava flow is moving, are there any buildings that are in danger, is there anything we can do to help with evacuation? And there have also been some long-term studies trying to see if we can predict volcanic activity a few days in advance, to see if the volcano is heating up slightly, is that indicative of an upcoming eruption or just an indication that we need to monitor more closely? And so, this is also an ongoing area of research.

Host: Very interesting. Now, I want to transition to your long-term research briefly, because you mentioned I think ECOSTRESS has been on the station, I think you said, for three years. That’s a lot of data. So, I wonder how your long-term study on water stress, heat stress, on plants, is going and how much more data you’re expecting to collect and what the long-term plan is for you?

Kerry Cawse-Nicholson: Well, how much data we would like is, is always infinite. We would like to continue —

Host: More, more data.

Kerry Cawse-Nicholson: Always more. [laughter] Never ask a scientist how much data they’d like.

Host: That’s on me. That’s on me.

Kerry Cawse-Nicholson: [Laughter] But no, so, we’ve worked, we’re working through the three years of data, and we’re really, it’s, it’s going well. So far we’ve seen these really interesting spatial patterns and how the drought developed, moving from 2018 when we started making these measurements, until now when we’re in this extreme drought throughout a lot of the western United States. And this isn’t something that happens like a wave, it’s something that happens sort of piecemeal where certain regions become stressed more quickly than others. And we’re in the process of trying to work out exactly why that is. And so that will be a long-term study. It will take time, and we’ll probably release several papers as we go and as we increase our understanding. But really, you know, you spoke about climate change early on, and I said that our measurement time hadn’t been long enough. But eventually, if we’re able to acquire this type of data for decades, that’ll give us a much greater idea of how this plant strategy is adapting over long time scales, which is important. So, ECOSTRESS is, it’s set to remain on the ISS until at least September of 2023, so we have some time left, and beyond that, will depend on space on the ISS and NASA reviews. But then we’re also planning future missions that might look quite a lot like this in order to maintain these measurements, because we’ve seen how important they are.

Host: Right, yeah. And we’re working on a long-term strategy at NASA to maintain a presence in low-Earth orbit, so experiments like these can continue for, you know, if decades is what’s needed to create a good model for understanding more about climate change, then certainly that’s an important experiment to look into. But I wonder in the nearer term, you said, you know, you’re here until 2023, at least on the space station, and at least that’s the plan, and then you’re looking forward and ahead of that; in your short-term efforts with urban areas, volcanos, wildfires, you were talking about ways to get the data that’s coming to you and get it over to people that can actually make a difference, whether it’s people dealing with wildfires or whether it’s someone who wants to test out a new paint on a road and see how that helps with the temperature changes in an urban area. I wonder if you have short-term plans to get information to American farmers, so they can make educated decisions on watering their plants at certain times of day, or how much water usage that they need to have, or if that’s maybe a longer-term strategy as part of the papers that you plan to publish later?

Kerry Cawse-Nicholson: It is an ongoing objective of ours, and it’s something that we’re continually working on, because NASA data is freely available to anyone, any of you listening can grab ECOSTRESS data right now, and there are some tools available. We have these archiving centers, we call them DAACs (Distributed Active Archive Centers), and so, our DAAC, the land processes DAAC, stores the ECOSTRESS data, and they also have a number of tools whereby you can highlight just one particular area. This is my farm, can you tell me how the ET has been changing over just my field? And it produces the data. You can even just get a CSV (comma separated value) file showing how one particular pixel has changed over time. You can get these GeoTIFF images that you can drag and drop into any standard GIS (Geographic Information System) software. And so, we’re really trying to make the data accessible so that you don’t have to be an expert to get the data you need. And so, this is something that is really ongoing, and we’re trying to work with the applications community as well to find out, what do you need, what can we do to make this data more accessible to you, because we really, really want people to use it. And it’s like, I think that will be ongoing, and we’re constantly developing new ways to make the data easier to access and to read, and we’re always open to, to comments and feedback from the community.

Host: Wonderful. Yeah, that delivery is, is so important, right, because that’s how these farmers that maybe are not as well versed in applied math as you are and how to analyze data, coming up with measurable results, here’s what you need to do to, to keep your plants healthy. And it sounds like in the beginning of our talk, Kerry, you mentioned that you were, you know, the initial plan for you guys on how you were going to use ECOSTRESS has evolved quite a bit. From using these, from using your data in the short term to help out with some of the areas I talked about before, and you also said that ECOSTRESS is covering a much larger area. I know, initially there was an international footprint. I think some of the areas that I saw defined from you guys were Brazil, Costa Rica, Portugal, Spain, and Cambodia, but it sounds like it’s something that’s expansive, and you can provide data through much of the world. Is that still part of the plan, is to have that data freely available to, to everyone that you at least are gathering data for?

Kerry Cawse-Nicholson: Yes, absolutely. It’s freely available to anyone. Anyone who wants it can get that data from anywhere in the world, and we’re trying our hardest to acquire data everywhere, as we’ve talked about before. More data, more data, more data.

Host: Yeah.

Kerry Cawse-Nicholson: We’re constantly pushing to get more data to cover as much of the world as we can. And we’re a little bit restricted by the ISS orbit so that we can’t get those very high latitudes.

Host: Sure.

Kerry Cawse-Nicholson: It’s like Northern Canada and up into the Arctic, but we can get, as you said, a lot of the area where humans live, and we’re really excited about that.

Host: So, I think one of the interesting applications of the data coming from ECOSTRESS looking down at the planet is, at least one of the ones that I saw, was water usage and water efficiency. So, a long-term strategy, or perhaps a long-term goal for, for, if the data from ECOSTRESS were to be widely applied, what could be some of the ways that the world, the farming community across, really across the world, can apply these data to make better decisions about using water? What are some of the ways that that could really help the planet?

Kerry Cawse-Nicholson: So, water use efficiency is the ratio between output versus input, and so, the ECOSTRESS PI (principal investigator) Simon Hook, likes to call it your crop per drop. [laughter] And so, you take the productivity of the crops or the vegetation, and you divide that by the amount of water they use, which is what we estimate from evapotranspiration. And that gives you an idea of how well these plants are using the water that they have. And this is important for quite a few different reasons. So, locally, because you spoke about individual farmers, it’s something that you can correlate to yield. So, how big is my harvest going to be versus the amount of water that I need to make available for my field? So, understanding that optimization is something that’s important for individual farmers. But also, that water use efficiency is important in climate models, in predicting what might happen in the future, and there are a lot of areas where that water use efficiency is particularly uncertain because these areas haven’t been well studied. And so, we are trying to contribute to the larger picture as well by better understanding how that changes. There are also impacts due to land cover change. And so, for instance, there was a recent paper published looking at the impact in the Amazon, and you can see the Amazon has a very high water use efficiency, but in all the areas that have been cleared recently for agriculture or pastureland suddenly has a very low water-use efficiency. And so, by switching out high-efficiency lands for low-efficiency lands, what does that mean for the ecosystem as a whole and for our climate predictions in general? That’s something that we’re trying to understand as well.

Host: Very interesting. Kerry, you’ve been working on this for a while. You said, you came onto the team right before the launch of ECOSTRESS, you have three years of data under your belt and a couple more years to go, at least in the short term with some longer-term plans. I wonder, taking a snapshot, looking back at the past three years and thinking about what you have to look forward to, what it’s been liking, what it’s been, what it’s been like working on the ECOSTRESS team with some of your colleagues at JPL, with colleague across NASA, and working with all of these, you know, with farmers, with urban planners, and you know, all this wildfire response people? Just everything, looking back and looking forward at your participation in this, what’s it been like to work with the ECOSTRESS team?

Kerry Cawse-Nicholson: It has been an absolutely incredible experience. I am so happy that I landed up as a part of this team. So, at JPL we’re actually a relative small group. ECOSTRESS, as cool as it is, is a relatively small demonstration project. And so, there are a few of us, and we’re very close-knit, we work very, very closely together. We each have our different, you know, areas of specialty, but we’ve worked so closely that I’ve learned so much about areas that I wasn’t an expert in before. For instance, you know, coming from an applied math background I didn’t know that much about plants, and so, now, having learned about plant strategies to the extent that it’s something that I’m actively researching, is just amazing. And the community has really been so supportive. You know, we’re having a community meeting that’s going on this weekend: hundreds of people are attending, and these are people from universities who are doing this research with their students, there are people from those user communities, like you said, people who are using this data to monitor fires, to monitor cities. All of those people are attending. There are international people in attendance as well. And so, ECOSTRESS, for a small mission, has really just reached so many people, which is amazing. You know, I spoke about our archiving center and the tools that they use to make data available. And ECOSTRESS, as small as it is, the request for our products are just as high as some of the really massive NASA investments. And so, it’s small mission that’s really impacted a lot of people. It’s brought together a wide community, you know, working with people in agriculture, people in urban planning, with people working with volcanos, with so many different application areas. It’s just been a really great learning opportunity. I have learned so much about so many different areas, and I’ve met so many different people, and everyone has just been really enthusiastic and eager to learn. So, it’s been a wonderful experience, and I really hope to maintain that and, you know, now I’ve met so many different people and made these connections, and I really want to just continue those relationships and continue our research together, combining my skills with other people who are far more skilled in say, agriculture, and I have colleagues I’m very close to at the U.S. Department of Agriculture, and in other areas as well. So, it’s been a wonderful experience.

Host: I just, and I think you’re one of those passionate people, Kerry. It’s definitely coming across, and it sounds like it’s been just awesome to work with such a team. And just, you know, from your perspective of that, right, you said, you’ve seen, you’ve very much enjoyed working with this team. From what you’re saying, it sounds like you’ve discovered a lot of value in what this team has to offer, and I wonder how that’s translated into your thoughts about low-Earth orbit as a platform and as a place to look down at the planet. You know, we have long-term strategies for working in low-Earth orbit. There’s a lot of microgravity research, but there’s a lot of Earth science experiments as well. And I wonder from your perspective, coming into this world and working with ECOSTRESS, having a better understanding of just the value of looking at the planet from a robust platform with all the power and data capabilities that come with the International Space Station, I wonder your thoughts about the importance of such a place?

Kerry Cawse-Nicholson: Oh, yeah. It is incredibly important, and you know, for ECOSTRESS in particular, a platform like the ISS is really the only way that we could have made those diurnal measurements. You know, typical satellites in polar orbit, they acquire data at the same time of day every time they come over, and so, being in this somewhat unusual, inclined orbit, like the ISS, has had these benefits that we, we, many people didn’t even anticipate at first. And so, there is such benefits in the orbit. There is such benefit in the fact that, that community, that communication strategy, all happens within the ISS, you know, taking care of that data, sending it down to Earth for us, that it’s also really beneficial in terms of the synergistic measurements that are made by other instruments. And we haven’t spoken about that yet, but there are quite a few other instruments on the ISS right now that can be used in collaboration with ECOSTRESS to, to draw even more amazing science questions. And so, one of them is called OCO (Orbiting Carbon Observatory)-3. It measures carbon in the atmosphere, and it’s also on the ISS. And so, we’re acquiring data at the same time, and you can use the data together to understand the carbon output. So, we talked about water use efficiency, and you can use some of the measurements made by OCO-3 to better understand the output of plant productivity. There are also spectrometers on the ISS. There’s, right now a Japanese instrument, and there’s a commercial German instrument, but there will soon be another NASA instrument launched next year called EMIT (Earth Surface Mineral Dust Source Investigation), and it’ll measure mineral dust and how it moves from the surface of the Earth into the atmosphere and spreads around the world. But those measurements can also be used to understand different soil types and different plant types, and so suddenly using that understanding in collaboration with understanding plant stress, you can actually gather a lot more information about why certain types of plants might be more stressed than others, given their environment and how their output changes using those carbon measurements from OCO-3. And so, it’s this really great opportunity to work together with a whole number of instruments that are orbiting on the ISS.

Host: See, that’s, I think that’s the perfect place to end, Kerry, because it’s not just about, you know, it sounds like the perspective itself from low-Earth orbit is important, but the International Space Station as a place to pull together these data from all these different experiments, you get really a much more round perspective of Earth science and it sounds like it helps with the whole community. So, I want to end there, Kerry. Thank you so much for talking about ECOSTRESS today and all the great measurements you’re doing with your long-term experiments and the short-term, you know, working with all these different communities, to really help the Earth. I think that’s what you’re doing with you and your team, and so, I very much appreciate your time to come on and talk about it today.

Kerry Cawse-Nicholson: Thank you so much for having me. As you can tell, I really enjoy talking about ECOSTRESS, and I enjoy sharing this information with everyone. So, thanks for letting me talk about it.

Host: Wonderful.

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Host: Hey, thanks for sticking around. It was a pleasure to talk with Kerry Cawse-Nicholson today about ECOSTRESS and all the great work that’s being done at the Jet Propulsion Laboratory. Really great to hear her passion. And I hope you check out some of the work that they’re doing at the Jet Propulsion Laboratory’s website and then, of course, the ECOSTRESS is one of many experiments on board the International Space Station. Check them all out at We are one of many NASA podcasts across the entire agency. Make sure you check them all out at You can find us there along with Curious Universe or Rocket Ranch or Gravity Assist. There’s a lot of cool stuff to listen to all across the agency. So, make sure you go ahead and follow them on Apple podcasts, Google podcasts, and Sound Cloud. We are on the Johnson Space Center pages of Facebook, Twitter, and Instagram, we, meaning Houston We Have a Podcast. You can use the #AskNASA on your favorite platform, whichever one; you can submit an idea for the show, maybe ask a question, just make sure to mention it’s for us at Houston We Have a Podcast. This episode was recorded on August 17, 2021. Thanks to Alex Perryman, Pat Ryan, Norah Moran, Belinda Pulido, and Simon Hook. And of course, thanks again to Kerry Cawse-Nicholson for taking the time to come on the show. Give us a rating and feedback on whatever platform you’re listening to us on and tell us what you think of our podcast. We’ll be back next week.