CLIMATE CABLE | With good weather and little luck, NASA’s newest Earth observation satellite will launch early Tuesday morning from Cape Canaveral, Florida. The flight will conclude nearly a decade of mission development and its payload could help usher in a new era of Earth sciences.
“It’s innovative,” said Jeremy Werdell, project scientist for the PACE satellite mission. “In 25 years at NASA, it is the first mission where I feel like I can grow rather than knowing exactly what awaits me. “Not only will it produce so much novel data that we don’t have at hand now, but it will indeed shed light on many new discoveries.”
PACE stands for Plankton, Aerosol, Cloud, Ocean Ecosystem – all of which the new mission will allow scientists to observe in greater detail than ever before. Polluting particles and tiny ocean organisms may not seem interesting on their own, but they are key to understanding some of the most important processes shaping the planet today, including climate change.
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Three new high-tech instruments make those observations possible.
The satellite is equipped with two polarimeters, which observe certain properties of sunlight as it bounces off objects or particles in the air below. These observations, in turn, help reveal specific characteristics of the particles hit by light. They are particularly useful for observing clouds and aerosols in the atmosphere, including dust, wildfire smoke, and industrial air pollution.
These are some of the most advanced polarimeters in existence, according to NASA scientist Kirk Knobelspiesse, polarimetry lead for the mission. Both are multi-angle instruments, meaning they collect images from a variety of different viewpoints, giving scientists the most complete images possible of the clouds and particles they are studying.
Today, few satellites have that kind of capability. And PACE instruments will be some of the only ones collecting public data.
The mission’s flagship instrument, the only one of its kind custom-built at NASA, is its Ocean Color Instrument (OCI), a spectroradiometer that measures the wavelength and amplitude of emitted light. More simply, it is an instrument that detects colors. And it’s really good at what it does: OCI can detect more than 200 bands of color information, from the ultraviolet spectrum through visible light to infrared.
This is an improvement over previous satellite missions, which have only been able to observe a few different blues, greens and reds. The new capabilities will allow scientists to differentiate between various plankton communities in the ocean, giving them new insights into marine ecosystems.
“By having information across the spectrum, we can look at pigments that we haven’t been able to do before,” said Antonio Mannino, the mission’s deputy project scientist for oceans. “An analogy we’ve used is going from a box of eight crayons to a box of about 248 colors.”
Clouds and climate mysteries
More detailed observations of the oceans and atmosphere can inform a variety of research, including studies on everything from toxic algal blooms to air quality and links between clouds and global warming.
Plankton communities are a leading indicator of marine health. These small organisms are the cornerstone of the marine food web, and knowing which species are present in a given part of the ocean can help scientists predict how much oxygen is in the water, what types of fish are out there, and how healthy they are. their populations are. . That is valuable information for the fishing industry.
The new observations may also provide early warnings about toxic algal blooms, which can harm not only fisheries and other marine organisms but also coastal human communities.
Plankton communities can even help scientists estimate how much carbon dioxide the ocean is absorbing from the atmosphere. This is valuable information for climate scientists trying to make projections about how quickly the planet will warm in the coming years.
PACE will also help researchers better observe aerosols and clouds in the atmosphere and address some of the biggest questions that are puzzling climate scientists today.
“There are two major uncertainties plaguing us in terms of where our future climate is headed,” said Mark Zelinka, an atmospheric scientist at Lawrence Livermore National Laboratory, who is not involved in the PACE missions. “One of them is humans and the other is clouds.”
Different types of clouds can warm or cool the climate, depending on physical properties such as the size, number and composition of their water droplets. Understanding the way clouds form and how they change as the planet warms is important for making accurate predictions about future climate change.
Aerosols are also closely related to cloud research. Clouds form when water droplets condense around small particles in the air. And different types of aerosols can affect the size and abundance of water droplets, altering the physical properties of clouds. But scientists still have many questions about how exactly these physical processes work.
“It is still quite uncertain to what extent aerosols are affecting clouds or in what way,” Zelinka said.
That’s why improving satellite observations is so important, he added. More data can help scientists better understand these processes and then incorporate them into the models they use to make projections about Earth’s climate future.
“We don’t have the ability to build the Earth in a lab,” said Knobelspiesse, PACE’s polarimetry lead. “Our only laboratory is the planet. But we can’t see the planet everywhere all the time. So having good observations will help us understand and improve our models, which will help us forecast what will happen in the future.”
PACE observations will also give scientists a better picture of pollution and air quality around the world, important information for scientists and policymakers seeking to improve human health.
The three instruments and their combined observations will help give scientists the most complete understanding yet of the close connections between Earth’s atmosphere and its oceans, Werdell said.
“Our contribution here, in terms of a big climate sense, is to better understand how aerosols, the ocean and clouds interact, with a view to effectively understanding their various functions in a warming atmosphere and, therefore, in a warming ocean. it gets hot,” he said.
‘The gold standard’
PACE is scheduled to launch no earlier than 1:33 a.m. ET on Tuesday, pending potential weather-related delays. The launch will turn the page after years of work.
According to Werdell, NASA scientists started thinking about the project about 20 years ago. The idea was to develop a mission that complemented NASA’s other Earth observation satellite initiatives, such as the long-running Landsat program, the ocean observing project SeaWiFS, and the Aqua mission, which focused on the water cycle. from the earth.
After more than a decade of thinking, planning and publishing reports on potential new Earth observing systems, NASA headquarters officially gave the project the green light in December 2014, according to Werdell. Since then, various project teams have exhaustively mapped out the mission’s technical specifications, its implications for scientific research, and its value to ordinary human communities, including its applications for fisheries and air quality monitoring.
The project was not without its challenges. The longest government shutdown in the country’s history (34 full days between December 2018 and January 2019) put many NASA staff on temporary leave. The Covid-19 pandemic subsequently caused substantial delays to the launch schedule, which was previously scheduled to occur sometime in fall 2022.
But there have also been good memories, Werdell said. On November 14, 2023, the PACE spacecraft was finally transported from NASA’s Goddard Space Flight Center in Maryland to the Kennedy Space Center in Florida, bringing the project to its home stretch.
“Putting it on the truck and seeing it get here to Florida was amazing,” Werdell said.
Once the satellite is in orbit, it will begin collecting data almost immediately, although it may take an additional month or two to perform all the necessary testing to make sure everything is online and working correctly.
“At the end of those 60 days, the floodgates open,” Werdell said.
The mission highlights NASA’s contributions to Earth and climate science, he added.
“There is nothing like this mission,” he said. “A combined interdisciplinary study of the sea and sky fills a niche that no other agency in the U.S. or abroad is addressing. “I think it will become the gold standard for why NASA Earth science exists.”
Reprinted from E&E News with permission of POLITICO, LLC. Copyright 2023. E&E News provides essential news for energy and environmental professionals.