The surface soil moisture data (SSM) are retrieved from the radar backscattering coefficients measured by the wind scatterometer (ESCAT) onboard of European Remote Sensing satellites ERS-1/2 using a change detection method, developed at the Research Group Remote Sensing, Department for Geodesy and Geoinformation (GEO), Vienna University of Technology (TU-Wien). In the TU-Wien model, long-term scatterometer data are used to model the incidence angle dependency of the radar backscattering signal. Knowing the incidence angle dependency, the backscattering coefficients are normalised to a reference incidence angle. Finally, the relative soil moisture data ranging between 0% and 100% are derived by scaling the normalised backscattering coefficients between the lowest/highest values corresponding to the driest/wettest soil conditions. The derived product represents the moisture content in the first 5 cm of the soil in relative units between totally dry conditions and total water capacity. The unit is degree of saturation [%], but can be converted into volumetric units [m3 m-3 ] with the help of soil porosity information.

 

Available Products

 

Name

Processor

Temporal
Coverage

Spatial
Coverage

Data Provider

ERS-1/2 ESCAT 50 km Soil Moisture Time Series WARP 5.5

1991-08-05 to 2007-05-31, with a data gap between 2001-01 and 2003-08

Global coverage until 2001, from 2003 onwards regional coverage

TU-Wien

ERS-2 ESCAT 25 km Soil Moisture Time Series WARP 5.4

1997-05-20 to 2003-02-17

Global coverage

TU-Wien

ERS-2 ESCAT 25 km Swath Grid
WARP NRT

1997-05-20 to 2003-02-17

Global coverage

ESA SSE