PALSAR2

PALSAR2, short for Phased Array type L-band Synthetic Aperture Radar-2, is the primary radar instrument on the Japanese Earth observation satellite ALOS-2 (Advanced Land Observing Satellite-2). Developed for all-weather, day-and-night imaging, it continues the mission of the earlier PALSAR instrument and is operated by the Japan Aerospace Exploration Agency (JAXA). The system provides regular radar imagery of the Earth’s surface to support scientific research, environmental monitoring, and disaster management.

PALSAR2 operates in the L-band of the microwave spectrum, roughly 1.2 to 1.3 GHz (center frequency near 1.27 GHz) with a wavelength around 23 cm. This longer wavelength enhances sensitivity to forest canopy structure and rough surface textures, enabling a range of data products. The instrument supports multiple imaging configurations, including high-resolution fine modes and wide-area ScanSAR modes, as well as polarimetric capabilities for detailed surface characterization. InSAR (interferometric SAR) observations are a key component, allowing measurements of ground deformation and precise topographic mapping over time.

Launched in 2014, ALOS-2 and its PALSAR2 instrument have been used for applications such as land-use and forest monitoring, agriculture, urban planning, and natural resource management. PALSAR2 data are valuable for disaster response, providing rapid, cloud-free imaging after events like earthquakes, floods, and landslides. The mission contributes to both national and international collaborations in earth observation, research, and hazard assessment.