Disaggregated Surface Soil Moisture Near-Real Time V2 0.5 km sampling

The disaggregated Surface Soil Moisture (SSM) product (H28) is derived from the ASCAT SSM NRT 6.25 km product (H122) and a set of static downscaling parameters obtained from Sentinel-1 backscatter timeseries. It maps the soil moisture content in the topmost surface layer (<5 cm) expressed in degree of saturation on the Equi7Grid with a spatial sampling of 0.5km.

• Coverage: Europe, provided as Equi7Grid T6 Tiles (600 km x 600 km)
• Resolution: 1 - 5 km, sampled at 0.5 km
• Timeliness: Metop B: <75 min, Metop C: <115min
• Dissemination: H SAF FTP
• Formats: NetCDF4

The ASCAT DIS SSM NRT V2 0.5 km (H28) product represents a disaggregated (downscaled) version of the ASCAT SSM NRT 6.25 km product (H122). The disaggregation method applies so-called directional downscaling parameters, which have been estimated using Sentinel-1 backscatter time series (2016-2019). These parameters describe the temporal correlation between local (0.5 km) and regional (6.25 km) backscatter signals in various spatial directions. Thereby, the temporal persistence of spatial soil moisture pattern play a fundamental role, also known as temporal stability of soil moisture. This important characteristic allows inferring a spatial relationship of soil moisture between different scales derived from a temporal comparison of backscatter signals. The directional downscaling parameters are static, i.e. merely serve to improve the spatial representation of ASCAT SSM. Like the coarse resolution base product (ASCAT SSM 6.25 km), the ASCAT DIS SSM NRT V2 0.5 km product represents the topmost soil layer (< 5 cm) and provides SSM expressed in degree of saturation ranging between 0% and 100%.

The DIS SSM NRT V2 product is sampled on the 0.5 km-sampled Equi7Grid. The Equi7Grid was chosen as working grid and spatial reference, since it is optimized for high resolution remote sensing data and high performance computing.