PACE Scientists Take to the Sea and Air (and Really High Air)
Narration: Ryan Fitzgibbons
Transcript:
Full power engines and liftoff of the Falcon 9 and PACE.
So you’ve successfully launched the newest ocean and atmospheric satellite: PACE.
It’s powered up, instruments working, tons of data flowing. So, all the hard work is done.
There’s still one more step to make sure all that data is 100% accurate before the science community gets a hold of it. And well, this is where things get complicated.
Bear with me here. So go down to the Shearwater. What time is the ER-2 overflying the Shearwater, and can the Twin Otter get there at that time?
Yes. Barely.
There's, there's no just doing it in clouds either, so--
Once again, do you know if there's clouds are going to be there in 11?
Can you confirm that for us? It's the first spiral that has the PACE overflight?
I want to make the Twin Otter overfly them.
I’m trying to climb at like, 200 feet per minute. It's, like, painful.
In terms of aerosols over land, we've maxed that out. We've done everything we need to do. The only thing we'd be trying to find clear conditions over the ocean with some aerosols there.
KIRK KNOBELSPIESSE
So PACE-PAX is making surethe observations of PACE are what we think they are. The idea here is to go into the environment to make measurements of the atmosphere, of the ocean, of the surface and compare those measurements to the satellite measurements of the same things to make sure that what our satellite is seeing all over the Earth is correct.
The PACE-PAX campaign has three main components: two aircraft and a ship. And all three need to operate in precise coordination with overpasses of the PACE satellite. Whether all three or individual components, the key is to sync up with PACE. The whole team understands that timing is everything.
2132.
2132...yeah, we’re good. Yeah. We’re good--
KIRK KNOBELSPIESSE
So one of the things that's going to be very important for us is to keep track of the timing of everything so that we're making measurements, say, on the boat when the aircraft is flying over or making measurements on the boat when spacecraft is flying over as well.
They also needed to track the kinds of different measurements they were after. To do that, the science team came up with a list of specific observation goals, some 25 different combinations of land, air and sea conditions that the PACE satellite could measure at any given moment. And all of these pieces come together in California.
KIRK KNOBELSPIESSE
So California is great because you can get to a wide variety of different conditions. California has large urban areas, has large agricultural areas like the Central Valley of California. It has high mountain ranges. Has lots of very interesting coastal areas, different types of coastal waters. There's a lot we can get to from California.
First stop is finding a really unique plane. NASA’s Armstrong Flight Research Center is home to a high-altitude aircraft, known as the ER-2. The ER-2 flies between 60 and 70,000 feet, about twice as high as a commercial airliner.
KIRK KNOBELSPIESSE
So this is about the closest one can get to an observation from space without actually being in space. This is high enough in the atmosphere that you can see the curvature of the Earth and that the sky looks very, very dark, almost black.
Mounted in the wings and nose are special airborne versions of the instruments on the PACE satellite, measuring atmospheric particles all over the state.
As of yesterday it looked like smoke was coming from Oregon, from the north. But today it looks like it's coming from the south--
KIRK KNOBELSPIESSE
You know, we're interested in aerosols, and smoke is a type of aerosol. And so we want it to be operating in a part of the world where we could find aerosols to use when we're checking our ability to measure them from space. So we chose California at this time of the year, September, in part because it's a bit drier at this time of the year. There's more likelihood for smoke from forest fires. It turns out that there were, rather intensive forest fires in the LA Basin not too long ago. We were lucky to at least be there at the right time and place to observe those very well. So we definitely have a lot of data that we're gonna be looking at, and it would be very good test case for us so that we can monitor these sorts of events all around the world accurately.
Meanwhile, out on the coast, PACE scientists on board the NOAA Research Vessel Shearwater are making daylong cruises to measure the atmosphere from the ocean surface, and collect data on how light interacts with water.
IVONA CETINIĆ
There’s many different instruments on Shearwater. They’re like different types of like robotic microsopes that are actually looking at the diversity of the plankton. They’re collecting different aspects of radiometry, which is pretty much to learn more how the light is behaving underneath the ocean and on the surface of the ocean. And that's exactly what PACE is looking. We're pretty much measuring everything that PACE is measuring from space, but like, for real, “in situ” as we call it.
Further up the coast, another plane takes the middle ground, below the ER-2 and above the Shearwater.
BRIAN CAIRNS
This plane flies between zero kilometers and 3 kilometers and measures everything below the other plane and below the satellite.
ADAM AHERN
We’ve uploaded a bunch of instruments on the Twin Otter so we can measure particles, clouds and some limited gas phase data in situ.
In situ, meaning, it's making measurements of what the air is like at that very point. This Twin Otter is equipped with an air intake, like a snorkel, bringing in air from the outside and splitting it into various instruments on board.
ADAM AHERN
So here you see a bunch of different cloud probes that were designed to measure scattering from the particles. There's also a probe here that measures larger particles that are hard to get into the airplane, things like dust or sea salt.
To get all those particles into the instruments, the flight plans often include strategic “spirals,” where the Twin Otter flies in circles upward through a column of air to capture the vertical distribution of aerosols. The Twin Otter also has a unique vantage point for observing a seasonal algal bloom of special interest to a mission like PACE: red tide.
PILOTS
Oh, there's a lot of red off our nose.
Yeah, is there?
Tons.
Oh, yeah.
Off, all off Moss Landing.
And off the right wing.
That's a lot of red.
KIRK KNOBELSPIESSE
Coordination of all of these parts of the mission, you know, getting the different airplanes or ships in the same location and place as the satellites are flying over, it's really complex.
Yep. Satellites. As in more than one. The PACE-PAX team is taking advantage of this massive campaign to validate the data from another satellite aimed at determining the role of clouds and aerosols in climate, EarthCARE.
We’re looking at EarthCARE and PACE over Reno. There’s repeated observations over Monterey--
SAM LEBLANC
I'm the person kind of planning out the paths for our sampling strategy for the ER-2, the Twin Otter, to have them coordinated as much as we can with the PACE satellite. It's all trying to put it all together, hopefully at the same spot at the same time, sampling the same thing.
Start that westernmost line at 1953, that's including two spirals in Monterey Bay.
Skipping Monterey first because it’ll be cloudy there.
-Okay.
-Right?
Going down to Santa Barbara first--like, this is what Brian was saying, right?
SAM LEBLANC
It's evolutionary, I feel like. It's revision. So we have an idea, and then we're like, oh yeah, well, if we extend this here, we might be able to get that connection, that coordination better.
On the last day for the Research Vessel, one of those coordination exercises needs the ER-2 and the Twin Otter to fly over the Shearwater.
So they're going for a trifecta overpass: a PACE, a spiral and an us?
Yeah!
PACE, Twin Otter--
Twin Otter, ER-2--
Da-naa-naaah!
We got 18 minutes to the overflight and--
Ten minutes to the Twin Otter overpass of the Shearwater.
Alright, let’s go up to just about 500 feet--
So the Twin Otter just turned, so I'm assuming they started their points, so they must be there.
-Yeah.
-They’re over it.
They’re over the Shearwater?
Cool. Alright.
Seventeen Twin Otter flights, thirteen ER-2 flights, fifteen day trips on the Shearwater, sixteen days of targeted observations during a PACE satellite overpass, and seven days for EarthCARE. A coordinated science campaign of this scale would not be possible without the scientists, weather forecasters, sailors, pilots, and support crews from across NASA, NOAA, universities and its international partners. The PACE-PAX team wraps a successful monthlong marathon of validation, leaving California with the data to not only check the current state of PACE, but also develop new algorithms and data products for a next-generation look at the ocean and atmosphere all over the globe.