JAXA ALOS/PALSAR Annual Forest/Non-Forest Mosaic

The JAXA ALOS/PALSAR Annual Forest/Non-Forest Mosaic is a global L-band SAR dataset covering forest extent from 1992 to present across three sensor generations: JERS-1 (1992 to 1998), ALOS PALSAR (2007 to 2010), and ALOS-2 PALSAR-2 (2015 to 2025).^[1] The mosaic component provides annual HH and HV backscatter composites; the Forest/Non-Forest (FNF) classification layer, derived from multi-year stacked input with target-year weighting, is available for 2007 to 2010 (PALSAR) and 2017 to 2020 (PALSAR-2).^[1][2] The JERS-1 period (1992 to 1998) provides mosaic imagery only; no FNF classification is available and coverage is HH polarisation only.

The product is distributed at 0.8 arc-second resolution, corresponding to approximately 25 m at the equator according to the JAXA EORC dataset page;^[1] some third-party aggregators cite 50 m.^[3] FNF classification for 2021 to 2025 was, according to the JAXA EORC dataset page as of May 2026, pending an algorithm revision. Version 2.6.0, released April 2026, is described on the same page as including improved geometric accuracy.

Data are freely available via registration and distributed as Cloud Optimized GeoTIFF (v2+) for recent vintages. The annual mosaic compositing reduces speckle but can smear sub-annual disturbance events; per-scene SAR analysis is required for event-level detection.^[1] Cross-generation time series carry discontinuities at sensor boundaries (1998 to 2007, 2010 to 2015) due to changes in instrument and FNF algorithm generation.^[2]