The Korea National Park Service, under the Ministry of Climate, Environment and Energy, announced Friday that satellite signals vary by forest type after analyzing national park forest changes using synthetic aperture radar imagery from Next-generation Small Satellite 2.

The research demonstrates that domestically developed satellite data can support continuous day-and-night observation of forested areas that are otherwise difficult to monitor due to clouds and fog.

Next-generation Small Satellite 2 is an imaging radar satellite developed by KAIST using domestic technology. It was launched aboard the Nuri rocket on May 25, 2023, and has since conducted observations using synthetic aperture radar, or SAR — a system that fires microwave signals at the Earth's surface and analyzes the returning backscatter to produce imagery.

The Korea National Park Research Institute used repeat-pass observation data collected from March 12 to Sept. 20, 2025, to build time-series imagery and map the location and type of forest-change signals across different observation periods.

When the institute analyzed SAR backscatter intensity — where lower values indicate smooth or moisture-rich surfaces such as lakes and flooded areas, and higher values indicate rough surfaces such as dense forest — broadleaf forests and plantation forests within the study area of Jirisan National Park showed distinct scattering characteristics.

Five rounds of observation over the Sancheong area of Jirisan from March through September 2025 revealed differences in backscatter intensity between broadleaf and plantation forests, confirming the potential to track further structural changes between the two vegetation types.

Through this satellite imagery analysis, the Korea National Park Research Institute established a foundational analytical framework that can be extended to forest-type classification, identification of suspected degradation sites and forest-change detection.

Repeat observation data collected over time can support early identification of forest decline, pest and disease damage, wildfire damage and recovery status, landslide-prone areas and land-use changes.

"Data from Next-generation Small Satellite 2 is a vital tool for monitoring forest changes across the vast expanse of national parks more frequently," Korea National Park Service chief Ju Dae-young said. "Going forward, we will integrate satellite, drone and field survey data to detect early changes in forest ecosystems vulnerable to climate change, and strengthen the scientific basis for disaster response — including landslides and wildfires — as well as conservation and restoration policy."

Real-world applications and key advantages of synthetic aperture radar (SAR) satellites [Korea National Park Service]
Real-world applications and key advantages of synthetic aperture radar (SAR) satellites [Korea National Park Service]

thlee@heraldcorp.com