Soil moisture Measurements Made by Earth Observation Satellites

CEOS EO HANDBOOK – MEASUREMENTS

Measurements > Land >
Soil moisture

Soil moisture plays a key role in the hydrological cycle. Evaporation rates, surface runoff, infiltration and percolation are all affected by the level of moisture in the soil. Changes in soil moisture have a serious impact on agricultural productivity, forestry and ecosystem health. Monitoring soil moisture is critical for managing these resources and understanding long-term changes, such as desertification, and should be developed in proper coordination with other land surface variables. Applications include crop yield predictions, identification of potential famine areas, irrigation management, and monitoring of areas subject to erosion and desertification, as well as for the initialisation of NWP models.

Detailed Measurement	Description*	Instruments	Timeline
Freeze/thaw Link:	Flag indicating whether the land surface is frozen or not	2 instruments
Soil moisture at the surface Link:	Fractional content of water in a volume of wet soil. Surface layer (upper few centimetres) - Physical unit: [ m3/m3 ] - Accuracy unit: [m3/m3 ].	26 instruments
Soil moisture in the roots region Link:	Sub-soil vertical profile of the fractional content of water in a volume of wet soil. Requested from surface down to ~ 3 m - Physical unit: [ m3/m3 ] - Accuracy unit: [m3/m3 ].	1 instrument
Surface inundation Link:	Flag indicating whether the land surface is inundated or not	2 instruments

* Description adapted from WMO.