Sang-Ho Yun: Improving Disaster Response with Satellites that See Through the Clouds

Photo of Sang-Ho Yun. Credits: NASA / Emma Hill

Photo of Sang-Ho Yun. Credits: NASA / Emma Hill

Sang-Ho Yun, a geophysicist at NASA’s Jet Propulsion Laboratory (JPL), has maintained a passion for the Earth since he was young. Early on, he also developed an interest in physics. Physics, he says, is “simple, beautiful and scalable.” Physics is a foundational framework that we can use to understand our universe and, for Yun, the dynamic, ever-changing Earth. Yun first studied Earth science at Seoul National University, where he also went on to receive his Master of Science degree. It was during his studies for his master’s degree that he also gained an interest in remote sensing and radar. From there, he went to Stanford University to receive his PhD in geophysics, specializing in remote sensing using radar.

After completing a postdoc with the United States Geological Survey (USGS) Yun accepted a job at JPL, where he was later approached to be a founding member of Advanced Rapid Imaging Analysis (ARIA), a project that brings Earth-observing satellite radar observations, GPS and other data to hazard science and response. Since then he has actively played a leading role in the ARIA project, in charge of damage and flood mapping using satellite radar data for disaster response. This application of satellite radar data applies the technologies he specialized in for his PhD thesis, which involved incredibly detailed measurements of ground deformation around volcanoes – down to millimeter-scale levels of change in ground elevation. Considering Yun’s technological expertise it is no surprise that he plays a crucial role in ARIA, which utilizes similar radar technologies to create damage proxy maps (DPMs) and flood proxy maps (FPMs) that detect changes caused by disaster events such as earthquakes and floods. Yun and the NASA Earth Applied Sciences Disasters program use these valuable maps from ARIA to aid decision-makers in response efforts to disasters all around the world.

This Damage Proxy Map (DPM), produced by ARIA and the Earth Observatory of Singapore (EOS) to aid in response efforts for Cyclone Amphan, shows likely damaged areas in red and yellow near the border of India and Bangladesh. The product was produced using

This Damage Proxy Map (DPM), produced by ARIA and the Earth Observatory of Singapore (EOS) to aid in response efforts for Cyclone Amphan, shows likely damaged areas in red and yellow near the border of India and Bangladesh. The product was produced using Synthetic Aperture Radar (SAR) data from the European Space Agency's Copernicus Sentinel-1 satellites. Credits: NASA/JPL-Caltech, EOS, ESA, Google

ARIA for the Disasters Program

ARIA utilizes Synthetic Aperture Radar (SAR), which is a form of high-resolution imaging radar that penetrates clouds and provides images during both day and night. Using this SAR data ARIA acquires, processes and produces products using Amazon cloud computing services. These products are then delivered to stakeholders and decision-makers following disaster events in multiple ways, including the NASA Disasters Program Mapping Portal. Through this process, ARIA provides data products with impressive speed and accessibility to decision-makers and responders after a disaster strikes. ARIA’s products provide an unparalleled level of efficiency that is crucial to timely damage assessment and strategic response efforts.

What is the ultimate goal of Yun’s work with ARIA for the NASA Disasters program? He says that there are many “tiers of goals” to his work, especially technically – but ultimately, Yun admits that he wants to save lives. To do so, he works to make ARIA “rapid enough, accurate enough, and reliable enough, so that first responders can actually use this kind of information to save people’s lives.”

He also describes how ARIA’s beneficial impact can be taken further to make a society more resilient. He explains that while response to disasters is crucial, implementing preventative measures that help mitigate future impacts of disasters is even better, preemptively reducing the level of damage that will occur. Using data from ARIA and collaborations with other agencies, “We can better prepare for the unavoidable.” Resources like ARIA are growing and improving, but the problem of disaster response and resilience remains an extremely complex process.

Story by Carmen Atkins and Gabriella Lewis