The global 25m PALSAR/PALSAR-2 mosaic is a seamless global
SAR image created by mosaicking strips of SAR imagery
from PALSAR/PALSAR-2. For each year and location,
the strip data were selected through visual inspection of the
browse mosaics available over the period, with those showing minimum
response to surface moisture preferentially used. In cases
where the availability was limited (e.g., because of the requirement
for observations during specific emergencies), data were necessarily
selected from the year before or after, including from 2006.
Shimada et al. 2014

The SAR imagery was ortho-rectificatied and slope corrected
using the 90m SRTM Digital Elevation Model.
A destriping process (Shimada & Isoguchi, 2002, 2010) was applied
to equalize the intensity differences between neighboring strips,
occurring largely due to seasonal and daily differences
in surface moisture conditions.

Polarization data are stored as 16-bit digital numbers (DN).
The DN values can be converted to gamma naught values
in decibel unit (dB) using the following equation:

  • γ₀ = 10log₁₀(DN²) - 83.0 dB


  • Backscatter values may vary significantly from path to path
    over high latitude forest areas. This is due to the change of
    backscattering intensity caused by freezing trees in winter.

More information is available in the provider’s
Dataset Description.

HHHH polarization backscattering coefficient, 16-bit DN.
HVHV polarization backscattering coefficient, 16-bit DN.
angleLocal incidence angle (degrees).
dateObservation date (days since Jan 1, 1970).
qaProcessing information.


JAXA EORC (producer, licensor)
Google Earth Engine (host)
STAC Version 0.6.2
License proprietary
Temporal Extent 12/31/2006, 4:00:00 PM - 12/31/2017, 4:00:00 PM
Citation Masanobu Shimada, Takuya Itoh, Takeshi Motooka, Manabu Watanabe, Shiraishi Tomohiro, Rajesh Thapa, and Richard Lucas, "New Global Forest/Non-forest Maps from ALOS PALSAR Data (2007-2010)", Remote Sensing of Environment, 155, pp. 13-31, December 2014. [doi:10.1016/j.rse.2014.04.014.](
Type image_collection
GSD metersm
cube:dimensions {"x":{"type":"spatial","axis":"x","extent":[-180,180]},"y":{"type":"spatial","axis":"y","extent":[-90,90]},"temporal":{"type":"temporal","extent":["2007-01-01T00:00:00Z","2018-01-01T00:00:00Z"]},"bands":{"type":"bands","values":["HH","HV","angle","date","qa"]}}