UC San Diego Satellite Concepts Examine Land, Ice and Sea From Above

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This article originally appeared in the fall 2024 issue of UC San Diego Magazine as “View from Above.”

Our planet is making headlines for all the wrong reasons — record-breaking heat, more extreme storms and melting glaciers are contributing to rising seas. In response, NASA’s new Earth Systems Explorers Program requested proposals for scientific missions that would advance understanding of climate change factors, such as greenhouse gases, ocean surface currents and changes in ice and glaciers around the world. 

Four finalists were selected and funded with $5 million to perform a one-year concept study for future missions. Of those four, two mission concepts are led by scientists from UC San Diego’s Scripps Institution of Oceanography. 

The teams, one led by glaciologist Helen Amanda Fricker and one led by physical oceanographer Sarah Gille, are now refining their mission concept studies to further advance our understanding of how the planet is responding to climate change. 

Together, the projects cover the entire globe: land, ice and sea.

Fricker, a polar scientist and director of the Scripps Polar Center, is leading Earth Dynamics Geodetic Explorer (EDGE). This proposed satellite will observe the three-dimensional structure of terrestrial ecosystems like forests and the surface features of glaciers, ice sheets and sea ice in the polar regions. 

“These ecosystems and the continent of Antarctica are so vast, you need to get a view from space to study them in their entirety,” says Fricker. 

“Monitoring these shifting ecosystems and melting polar regions in real time can help us understand how the planet is responding to climate change, how we can mitigate the effects and if we are crossing critical tipping points that will cause abrupt or irreversible change,” she says. “The time is now to invest in this technology.” 

The proposed EDGE satellite will use imaging lidar altimetry, a technology that sends laser pulses to Earth’s surface and records the time it takes them to return to the spacecraft. This technology allows scientists to determine the height of Earth’s surface, including ice sheets, and structure of vegetation like the Amazon rainforest.

“It’s like using a laser pointer, but instead of one laser beam the satellite will have 40 lasers, giving us very detailed resolution, down to the depths of cracks in glaciers and the height of single trees,” says Fricker. 

In addition, the data from EDGE could transform our understanding of how Earth’s vital carbon and ice stores are changing, inform policymakers and provide vital data for scientists who project future conditions, such as in the United Nations’ Intergovernmental Panel on Climate Change reports. 

The second UC San Diego team satellite concept, led by Gille, whose research focuses on ocean dynamics and their role in Earth’s climate system, is called Ocean Dynamics and Surface Exchange with the Atmosphere (ODYSEA). 

The understanding of the planet as a system requires measurement at the air-sea interface, where the ocean meets the atmosphere. In this transition zone between ocean and atmosphere, clouds form, storms initiate, carbon dioxide in the atmosphere is absorbed by the ocean and nutrients are transported into ocean ecosystems. This proposed satellite would measure ocean surface currents globally — for the first time — and simultaneously measure winds over the ocean. ODYSEA would then provide a better understanding of these interactions, improving knowledge of our weather, climate and marine ecosystems.

“The weather systems that disrupt human lives initiate from the ocean — including hurricanes, tornadoes, atmospheric rivers and torrential flooding — and also the heat dome effects that give us massive heat waves,” says Gille. “This is one of the greatest challenges in climate science and critically important for understanding how the ocean is fueling extreme weather.” 

The ODYSEA satellite would offer entirely new capabilities by measuring daily global surface currents and their interactions with winds. This data would improve weather and climate predictions because it could show how ocean currents influence the atmosphere and improve weather, climate and ocean circulation models. This information may also be useful for search-and-rescue operations and tracking events such as oil spills. 

The technology powering ODYSEA will be a Doppler scatterometer. Scatterometers use radar signals to measure wind speed and direction. A new innovation, ODYSEA will also measure the speed and direction of surface currents by taking advantage of the Doppler shift in the radar signal due to the motion of the ocean surface.

The international teams, led by Fricker and Gille, are now finalizing the technical capabilities of the proposed NASA missions, demonstrating feasibility and refining satellite design so that the missions can be executed on time and on budget. In 2025, NASA will choose two of the four accepted proposals to move forward to launch: one in 2030 and one in 2032. Each would have a budget of $310 million. 

While the Scripps-led teams are each seeking one of those two coveted spots, both scientists agree that the satellite missions complement each other in approach and targets. 

“We really need both missions to span the entire surface of our planet,” adds Gille. 

Both satellite projects offer a transformational opportunity to further advance our understanding of the changing planet — but this time from space.