First data from UMBC’s HARP2 instrument on NASA PACE mission goes public

Published: Apr 11, 2024

The background of the image is entirely black, with an illustration of Earth centered on Africa in the top right corner of the image. The HARP2 logo lies below the Earth illustration. A small box is highlighted over Western Africa and two lines are extending out from it, meeting with two larger images which take up most of the image, indicating that the larger images are zoomed in to the location highlighted over the Earth. The larger image to the left has a label above it in white that says “True Color Image”. It shows a portion of land on the right side of the image in shades of brown. The left side of the image is primarily the dark blue color of the ocean. Over the land and ocean, primarily in the top left corner of the image and along the right border are wisps and speckles of clouds. The larger image to the right, which has a label above it that says “Polarization”, is the same as the left image, but with inverted colors. The land shows up as a dark black color, while the ocean is seen as a brighter blue. The clouds now show up in a range of colors. The clouds on the right border of the image appear in shades of muted greens and oranges, and as the clouds extend over to the top left corner, they are seen in a full rainbow color. From right to left, the colors transition from dark purple, through the rainbow to end at red.
The first images from PACE’s HARP2 polarimeter captured data on clouds over the west coast of South America on March 11, 2024. The data can help scientists better understand the cloud droplets that make up the cloudbow—a rainbow produced by sunlight reflected from cloud droplets instead of rain droplets. Scientists can learn how the clouds respond to pollution and other particles in the atmosphere. They can also measure the size of the cloud droplets with HARP2's polarimetry data. (UMBC)

Data from NASA’s newest Earth-observing satellite, which will provide insight into ocean health, air quality, and the effects of a changing climate, are now available. The Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) satellite launched on February 8, and after several subsequent weeks of testing of the spacecraft and instruments, the mission is gathering data that the public can access.

PACE includes three instruments: The Ocean Color Instrument (OCI), built at NASA Goddard Space Flight Center, observes the ocean, land, and atmosphere across more than 200 unique wavelengths spanning ultraviolet, visible, and near infrared light. It is particularly suited to identifying phytoplankton communities in the ocean. 

HARP2, designed and built by UMBC scientists and engineers, and SPEXOne, built at the Netherlands Institute for Space Research (SRON) and Airbus Netherlands B.V., are both polarimeters, which measure light that has reflected off clouds and particles in the atmosphere. These particles, known as aerosols, can range from dust to smoke to sea spray and more.

“First light,” as the first data received from satellites in orbit is known, is a key milestone in the progression of any scientific instrument destined for space.

“When I look at the first light PACE images, I feel like I have put on magical eye glasses and am seeing the true characteristics of aerosol plumes from a satellite for the first time.”

Lorraine Remer

UMBC Climate Scientist

“To me, first light means the conclusion of all the engineering work to develop HARP2 and the beginning of our science quest exploring and understanding the data from PACE,” shares Vanderlei Martins, professor of physics at UMBC and lead of the HARP2 team.  “First light means  ‘It is working!’ and the question right after first light is, ‘What does it mean?’”

Answering big questions about Earth’s interrelated systems

With data from PACE’s polarimeters, scientists will be able to measure cloud properties and monitor, analyze, and identify atmospheric aerosols to better inform the public about air quality. Scientists will also be able to learn how aerosols interact with clouds and impact cloud formation, which is essential to creating accurate climate models.

The HARP2 team will focus on air pollution, the effect of aerosols produced by humans on cloud formation, and the energy balance of the planet, Martins says. “We will learn about the type of aerosols in Earth’s atmosphere: What they look like in terms of size and shape matters in terms of their health effects,” he says. “The way they absorb and scatter light affects how they interact with solar radiation and influence the energy balance of the planet: Do they produce heating or cooling of the planet, and in which circumstances?”

“I have plans to use PACE aerosol and ocean products to better understand how nutrient-rich aerosols are deposited into the global ocean and how ocean plankton communities respond to this nutrient source,” adds Lorraine Remer, a UMBC climate researcher affiliated with the Goddard Earth Science Technology and Research Center II, one of UMBC’s NASA-partnered research centers.

First, though, “We will spend the next weeks and months tuning our parameters to coax out the most and best possible information on aerosols and clouds,” Remer says. “Then, the next step is to compare PACE’s output with established sensors on the ground.” A validation experiment in September 2024 called PACE-PAX will enable and encourage those comparisons.

The top right corner of the image shows a nearly quarter-circle shaped piece of land, which is a brown-orange color. There are speckles of clouds covering the top right-most corner of the land. The rest of the image is taken up by ocean, showing the coast of the ocean where it meets the land. The ocean is split up into three segments, each colored differently, with the middle section the largest. The section to the left shows the ocean in true color. There are white wispy clouds covering parts of the ocean from top
The Ocean Color Instrument (OCI) has the unique ability to detect light that allows scientists to differentiate among communities of phytoplankton. This first image released from OCI identifies two different communities of these microscopic marine organisms in the ocean off the coast of South Africa on February 28, 2024. The central panel shows Synechococcus in pink and picoeukaryotes in green. The left panel shows a natural color view of the ocean, and the right panel displays the concentration of chlorophyll-a, a photosynthetic pigment used to identify the presence of phytoplankton. (Image by NASA)

PACE lets scientists put on “magical eye glasses”

Because of the power and unique capabilities of the instruments on PACE, “We see confident atmospheric parameters that have never been seen from any previous NASA mission,” Remer says. And because the data will be completely public, the benefits will go far beyond work that current PACE scientists will do.

“PACE data will be free for everyone around the globe and will be useful for decades to come,” Martins says. “Events on Earth will come and go, and they will be recorded forever by the PACE sensors. Beyond our own science studying aerosols, clouds, and the energy balance of the planet, this data will be explored by students and scientists for all sorts of applications that I can’t even imagine.” 

Martins expects UMBC scientists to write proposals to analyze PACE data for many years, and many of these projects will involve opportunities for students at all levels to gain experience with research. For now, PACE scientists are still relishing the successful launch and return of first light from the PACE instruments.

“When I look at the first light PACE images,” Remer says, “I feel like I have put on magical eye glasses and am seeing the true characteristics of aerosol plumes from a satellite for the first time.”

Jeremy Werdell, PACE project scientist, shepherded the project from start to finish, beginning when Martins pitched him the idea of including a HARP2-like instrument on board. “We’ve been dreaming of PACE-like imagery for over two decades. It’s surreal to finally see the real thing,” he says. “The data from all three instruments is of such high quality that we can start distributing it publicly less than two months from launch, and I’m proud of our team for making that happen.”

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