The dataset contains all ESA acquisitions over the ADEN zone (Europe, Africa and the Middle East) plus some products received from JAXA over areas of interest around the world. Further information on ADEN zones can be found in this technical note (https://earth.esa.int/eogateway/documents/20142/37627/ALOS-ADEN-Zone.pdf). ALOS PALSAR products are available in following modes:• Fine Beam Single polarisation(FBS): single polarisation (HH or VV), swath 40-70km, resolution 10m, temporal coverage from 02/05/2006 to 30/03/2011 • Fine Beam Double polarisation (FBD): double polarisation (HH/HV or VV/VH) ), swath 40-70km, resolution 10m, temporal coverage from 02/05/2006 to 30/03/2011 • Polarimetry mode (PLR), with four polarisations simultaneously: swath 30km, resolution 30m, temporal coverage from 26/08/2006 to 14/04/2011 • ScanSAR Burst mode 1 (WB1), single polarization: swath 250-350km, resolution 100m, temporal coverage from 12/06/2006 to 21/04/2011 Following processing levels are available: • RAW( level 1.0): Raw data generated by every downlink segment and every band. Divided into an equivalent size to one scene. • GDH (level 1.5):Ground range Detected, Normal resolution product • GEC (level 1.5): Geocoded product

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. Only data from the target year have been used for each annual mosaic, and hence no gap-filling using data from previous years in case of gaps in the annual global coverage. There is no data for 2011-2014 due to the gap between ALOS and ALOS-2 temporal coverage. The SAR imagery was ortho-rectificatied and slope corrected using the digital surface model ALOS World 3D - 30m (AW3D30). 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 Attention: 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.

A newer version of this dataset with data for 2015-2021 can be found in JAXA/ALOS/PALSAR/YEARLY/SAR_EPOCH 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 There is no data for 2011-2014 due to the gap between ALOS and ALOS-2 temporal coverage. 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 Attention: 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.

Digital Earth Africa provides access to Normalized Radar Backscatter data, for which for which Radiometric Terrain Correction (RTC) has been applied so data acquired with different imaging geometries over the same region can be compared. The ALOS/ALOS2 PALSAR is a global 25 m resolution dataset that combines data from many images captured by JAXA’s PALSAR and PALSAR-2 sensors on ALOS-1 and ALOS-2 satellites respectively. This product contains radar measurement in L-band and in HH and HV polarizations. It has a spatial resolution of 25m and is available annually for 2007 to 2010 (ALOS/PALSAR) and 2015 to 2021 (ALOS-2/PALSAR-2). ALOS/ALOS2 PALSAR mosaic data is part of a global dataset provided by the Japan Aerospace Exploration Agency (JAXA) Earth Observation Research Center. The relevant coverage and metadata of ALOS/ALOS2 PALSAR dataset can be viewed on DE Africa Metadata Explorer.Key PropertiesGeographic Coverage: Continental Africa - approximately 37° North to 35° SouthTemporal Coverage: 2007-2010, 2015 - 2021; Observation date is expressed as days after launch, which are Jan. 24, 2006 and May. 24, 2014 for PALSAR and PALSAR-2 respectivelySpatial Resolution: 25 x 25 meterUpdate frequency: Annual from 2007 to 2010 & 2015 to 2021Product Type: Radar backscatterProduct Level: Radiometric Terrain Corrected (RTC)Number of Bands: 5 BandsSource Data Coordinate System: WGS 84 (World Geodetic System 1984) (EPSG:4326)Service Coordinate System: WGS 84 (World Geodetic System 1984) (EPSG:4326)Available BandsBand IDDescriptionData typeNo dataHHHH backscatteruint160HVHV backscatteruint160dateObservation date (days since launch)uint160linciLocal incidence angleuint80maskProcessing mask informationuint80Backscatter data is provided as digital number (DN), which can be converted to backscatter in decibel unit using 10*log10(DN2) - 83.0 dB.A data mask is provided that can be used to exclude pixels with potentially problematic measurements.More information about the dataset can be found on the JAXA dataset description page.

The Advanced Land Observing Satellite-2 (ALOS-2), launched May 14, 2014, is a follow-on mission to ALOS. ALOS-2 features an imaging microwave radar, PALSAR-2 (Phased Array type L-band Synthetic Aperture Radar-2). With a wider range of observation modes PALSAR-2 improves on its predecessor PALSAR (which flew onboard ALOS). PALSAR-2 observes in the L-band, specifically 1257.5 MHz which is adjustable by ± 21 MHz. ScanSAR mode provides a spatial resolution of 60 m and 100 m for a swath of 490 km and 350 km respectively. Stripmap mode provides a resolution of 10 m, 6 m, and 3 m for a swath of 70 km, 70 km, and 50 km respectively. Spotlight mode provides a resolution of 1 m x 3 m for a swath of 25 km x 25 km. ALOS-2 also decreased the revisit time of its predecessor from 46 days to 14 days. ALOS-2 also has the ability to look either to the right or the left.

This collection provides open access to ScanSAR mode data acquired by ALOS-2. Recently acquired data are not included but are added when released for open access by JAXA. Although the ScanSAR mode has been acquired globally, the collection currently contains only partial global coverage, but coverage is increasing as data become available.

Products have been processed by JAXA as Level 1.1, such that range and single look azimuth compressed data is represented by complex I and Q channels to preserve the magnitude and phase information. The range coordinate is in slant range. The image is focused onto zero Doppler direction, and an image file is generated per each scan for ScanSAR mode. In addition the full aperture processing method was used to generate the products. With the full aperture method, range compression and one look azimuth compression are performed for the data whose gaps between neighboring bursts in a sub swath are filled with zeroes, this processing is performed for each scan and each polarization. Granules in this collection are distributed as a zip and are quite large, with the majority being 28GB (single polarization) or 56GB (dual polarization).

ALOS World 3D - 30m (AW3D30) is a global digital surface model (DSM) dataset with a horizontal resolution of approximately 30 meters (1 arcsec mesh). The dataset is based on the DSM dataset (5-meter mesh version) of the World 3D Topographic Data. More details are available in the dataset documentation. …