GCOS target requirements for soil moisture were set as follows (GCOS-245):
Variable/Parameter | Horizontal Resolution | Temporal Resolution | Latency | Required Measurement Uncertainty | Stability* |
---|---|---|---|---|---|
Surface Soil Moisture | 1 km | 6 hrs | 3 hrs | 0.03 m3/m3 | 0.005 m3/m3/decade |
* Stability requirements are noted to “still lack justification in the scientific literature and need to be critically assessed.”
LPV Soil Moisture contributions towards action items T15, T16, T17, T18 (IP 2016/GCOS-200).
Currently the most extensive global in situ reference data base for satellite-derived soil moisture product validation is the International Soil Moisture Network (ISMN), where scientific and operational in situ networks and campaigns contribute data for communal use. The ISMN harmonizes the data, applies automated quality control procedures, and makes the data avialable for download and viewing.
A sophisticated cloud-based service for soil moisture validation of satellite and simulation products is the Quality Assurance for Soil Moisture (QA4SM) framework, which brings together fiducial reference measurement (FRM) data, as well as best practice methodologies and protocols used for the validation and quality control of soil moisture data products and provides users with traceable validation results.
QA4SM builds on the open source Python Toolbox for the Evaluation of Soil Moisture Observations (pytesmo), whick aims to become the standard library for the comparison and validation of geospatial time series datasets with focus on soil moisture.