NASA Hunga Tonga Interview Transcript
Allyson
Welcome to the Tech Arena. My name is Allyson Klein, and today I'm delighted to be joined by research scientist Ryan Stauffer at NASA's Goddard facility. Welcome to the program, Ryan.
Ryan
Thanks so much for having me, Allyson. Happy New Year. Appreciate the invitation.
Allyson
Ryan, you are undertaking some important work for NASA's SHADOZ program. As part of your work at NASA Goddard, can you just start with an introduction of your role at NASA and how it relates to SHADOZ?
Ryan
Sure. So, as you said, I'm a research scientist at NASA's Goddard Space Flight Center. It's located in Greenbelt, Maryland, just outside the DC beltway. I've been in my current role as the principal investigator of the SHADOZ balloon born Ozone San network that's SHADOZ since June of 2021. SHADOZ stands for the Southern Hemisphere Additional Ozone Sans Network. And so it's a network of currently 14 active balloon born ozone san stations in the tropics and subtropics, basically covering all of the tropical areas. And so they collect these balloon born measurements of ozone about two to four times per month. And so this network has been in existence since 1998. So actually, we're celebrating 25 years of SHADOZ measurements. And actually this year, later in 2023, we will collect the 10,000th one of these balloon born profiles. And so when you connect one of these small, lightweight ozone measuring instruments to a balloon, it gives you the entire profile. So you're measuring ozone all the way from the ground up to about 20 miles or 30 km up in the atmosphere before the balloon bursts and everything falls back to Earth. So those are the measurements that the SHADOZ network collects.
Allyson
Now, SHADOZ is part of NASA's larger use of scientific balloons for atmospheric measurement. Why are balloons something that are effective tools for measurement? And why would you decide to choose a balloon versus another tool like a satellite?
Ryan
Well, yes, exactly. When I tell people that I work for NASA, it's always a bit of a head scratcher for them, because NASA is in the business of putting things into space and taking measurements of the Earth and beyond and human exploration. But the reason that NASA is interested in collecting these balloon born measurements is because, one, we need to make sure that the satellite measurements are accurate. And another aspect, maybe ozone, is a really nice example of this, is that when a satellite is staring down through the atmosphere, it has to look through the ozone layer up in the stratosphere, somewhere around 15 miles above the Earth or so. And around 90% of all of the ozone in the atmosphere is located in the stratosphere, in the ozone layer. So satellites have a very difficult time determining how much ozone is at the surface where we would say ozone is polluted. So ozone, the phrase we like to use, is good up, high, bad nearby. And if you want the entire complete picture, the ground level ozone where it's a harmful pollutant, and the ozone layer ozone that protects us from the sun's harmful UVs, you need these balloon born measurements to give you that complete picture. And the satellites are complementary to that.
Allyson
So today is the one year anniversary of the Hunga Tonga eruption in the South Pacific. This was quite a powerful eruption from the sea floor, to say the least. Can you tell us about that and why it made SHADOZ even more important to our science?
Ryan
Absolutely. Just an enormous cataclysmic eruption that occurred at about 20 degrees south latitude in the remote Pacific Ocean. The really unique aspect of this eruption was not just its intensity, and it looks like it was the strongest, most powerful eruption since at least 1991 with Mount Pinatubo in the Philippines. But the unique aspect was that it was an underwater volcano. So it blasted just copious enormous amounts of water vapor into the stratosphere, the normally very dry stratosphere. And so over the course of a day or two, the amount of water vapor located in the stratosphere over the entire globe increased by about 10%. So just an enormous ejection of the water vapor.
SHADOZ’s role in monitoring this is that we already have stations set up near where the eruption went off. In addition to measuring ozone, we also measure water vapor in the stratosphere at many of these locations. And so we were able to track this enormous injection of water vapor into the stratosphere by measuring that and also potential chemical effects that might cause the ozone in the stratosphere to change. So we were able to measure that both the water vapor and effects on ozone, in particular at a location called Reunion Island, which is near Madagascar. So right after the eruption we were able to observe the effects and it's potential chemical ozone depletion as well.
Allyson
When you look at Honga Tonga, can you put in perspective how large of an eruption this was compared to other eruptions that we've observed over time? And what is the impact of having that water vapor in those levels of the atmosphere in terms of impact to the health of the planet?
Ryan
There has never been in our record of observations over many decades this amount of water vapor shot right into the stratosphere from a volcano. In the past, there were certainly more explosive eruptions, eruptions that might have placed a lot of sulfur dioxide into the stratosphere, which can cool the planet. This eruption from Hunga Tonga only injected a few percent of sulfur dioxide compared to say, Mount Pinatubo did in 1991. And so Mount Pinatubo had an effect of cooling the planet. However, with an injection of water vapor like from Hunga Tonga, that may end up slightly warming the planet because of the radiative effects of water vapor. So it could warm the surface. But locally in the stratosphere where the water vapor is located, that has had an intense cooling effect on the stratosphere. And so the southern hemisphere subtropics around 20 to 35 degrees south, for example, up around 20 km or so in the atmosphere, those temperatures are at record low levels because of the water vapor. So it's having a profound effect on our climate.
I think it's yet to be seen exactly what the effect will be on surface warming, but we have already observed intense cooling in the stratosphere, so it's been a really interesting case to follow.
Allyson
Interesting. Tell me a little bit about what the broader scientific community will do with the data that's coming out of your measurements in terms of understanding that broader picture and helping mitigate. Is there anything we can do from a mitigation standpoint in terms of understanding what's happening to the planet from this eruption?
Ryan
I think one aspect that we'll learn a lot about is how air moves and circulates is in the stratosphere, because this water vapor is going to be up there for years. We're already at one year, and it's clearly still observable from balloons from satellite measurements. And the water vapor really doesn't have, for lack of a better term, a sink in the stratosphere. So it just moves around. It's going to eventually get mixed down to the lower atmosphere where there's much more water vapor. And so that enhancement signal will eventually disappear in a few years. But we are going to learn a lot about how air moves in our upper atmosphere between now and then. Certainly.
Allyson
Now, balloons themselves are considered and may be viewed by many of our listeners as relatively low on the tech range of NASA's extensive tools. When we think about rockets and satellites and everything that NASA has at its disposal, one doesn't really think about balloons. But you use balloons very specifically, and I know that you're using advanced technology and your research beyond the balloons. Can you give us some insight into the workflow between the moment that you launch a balloon and the types of balloons that you're using and how you gather the data from balloons all the way into publishing your results for the broader scientific community?
Ryan
Well, yes, the ozone sand and balloon born instrumentation in general is considered fairly low tech. The lightweight ozone sand that we use in the Shadows network, that technology has existed for around 60 years, actually. But it's a tried and true method. We quantify exactly how well they work and exactly how accurate they are through laboratory measurements and other field experiments. One of the key advantages to balloonborn instrumentation, which are actively sampling the air as they go up in the atmosphere, is that they're all weather instruments. They're not affected by clouds. They're not affected by rain, rain or shine, essentially. You can collect accurate measurements in this case of ozone, and satellites do not perform well with many types of measurements when there's heavy cloud cover. And so ozone sons fill that role. But, yes, there's certainly a number of measurement platforms and computing modeling that all go into, I would say, complete the picture.
So. We launch these balloons, get a full profile of the atmospheric ozone, we compare it to the satellite measurements, validate the satellite measurements. The satellite measurements are often ingested into computer models, and then we can turn around and see how accurate those computer model simulations are compared to the balloon born instrumentation, for example. So all of these different puzzle pieces, I would say, get plugged in to complete the picture. And so validation exercises are a lot of what we end up publishing. We quantify how well the satellites are measuring, how well they compare with the ozone sons, and then ultimately, how good are we at simulating atmospheric ozone through a number of models that NASA and other agencies run.
Allyson
Now, obviously, Hunga Tonga is an acute example of why this science is so important. But the SHADOZ network was well established when Hunga Tonga happened. What are the broader scientific implications of measuring ozone in the layers of the atmosphere? And what areas of science tap your team's data for their broader research?
Ryan
So, SHADOZ was initiated back in 1998 after a number of NASA aircraft campaigns which are measuring chemistry in the atmosphere, noticed some peculiarities about ozone in the tropics, and in particular, this maximum that was located over the tropical South Atlantic. So there was a lot of pollution that were measured in these campaigns way back in the late eighty s and early ninety s. And so one of the things that NASA realized is that there was really no established network of bloom born ozone's on stations in the tropics. These, these stations have existed in the mid latitudes in Europe, in the United States, in Canada for 50 or more years. But there was nothing like that in the tropics. And so SHADOZ again filled a gap in our measurement capabilities by providing ozone profiles in the tropics, a really critical area. And so we don't think about just pollution. With the SHADOZ tropical ozone san network, we're also looking for climate effects. One of the most recent publications we had from 2021 was looking at how ozone is changing. NASA and many other agencies are really interested in how ozone trends are behaving for the Montreal Protocol and the protection of the ozone layer, monitoring the health of the ozone layer, but also how pollution is changing and also what effects climate change has on those ozone changes.
And so we found in this 2021 paper that the tropopause, the boundary between the troposphere where we live and where all the weather happens, and the stratosphere where the ozone layer is, that tropopause is actually raising in altitude because the surface is warming. And that has an effect on ozone. And so we were able to say, well, this change in ozone is a climate effect. It's not some unexpected chemistry. It's not an indication that the Montreal Protocol for protecting the ozone layer is failing. But we are literally seeing climate change effects on how ozone is shaping.
Allyson
When you look at the work you've done with SHADOZ and you look at the opportunity with Hunga Tonga, talk me through what happened when that eruption happened, did you know right away that this was going to pose a real challenge and opportunity to your team to provide vital measurements of what was happening? Or did that come over time for you?
Ryan
My phone was ringing the night it happened. Immediately. When you see a volcanic eruption like that, you want to spring into action. But the eruption didn't turn out how we initially thought it would. I mentioned that many volcanoes like mount Pinatubo inject a lot of sulfur dioxide into the stratosphere, which causes a lot of particles and cools the planet. This one totally threw us for a surprise by the amount of water vapor it had up there. And so I mentioned previously that at Reunion island near Madagascar, that they collected a number of water vapor and ozone balloon measurements. And so that was actually a mini campaign where a number of scientists flew to the island just within a week and were able to capture the initial plume from this eruption as it went over Reunion island. So everybody really sprung into action. As I said that day, we were already trying to make plans to see how we could collect these measurements and how we could quantify the initial stages of the plume.
And so that was the initial reaction to collect immediate measurements. And now it's going to be long term monitoring. The water vapor will be there for years. We will be able to measure it for years, and it's just tracking its evolution, comparing our measurements to satellite measurements and learning more about how air is moving up in the stratosphere.
Allyson
Well, really important work. Ryan, thank you so much for sharing your story today. The SHADOZ program in Hunga Tonga is part of a much broader effort from NASA in terms of measuring air pollution and our atmosphere. And this area of NASA's purview doesn't get enough attention in terms of the contributions that you're making to understanding the planet. So thank you for spending some time with us today. I know that we've piqued the interest of folks who are listening online. Where can folks find out more about what you're doing and keep up to date with what the shadows program is delivering?
Ryan
Sure. Well, first, it was a pleasure to be here and speak with you today, Allyson. If folks want to learn more about the SHADOZ network and our ozone measurements, I think it's easiest to just Google SHADOZ. That's S-H-A-D-O-Z southern hemisphere and digital ozone sans. And it will take you right to the NASA Goddard web link and you can find all the information on SHADOZ. You can find our data. Our data are public open access, so anyone can download them and use them. And I would say, yeah, that's the easiest way is just to Google us.
Allyson
Fantastic. Thanks for being on the show today.
Ryan
Thank you, Allyson. It's a pleasure.