Quality Assurance for High Spatial and Temporal Resolution Soil Moisture Data

The Quality Assurance for Soil Moisture (QA4SM) initiative aims to become the international benchmark service for validating satellite soil moisture products. The QA4SM-HR project builds on the initial development in the preceding QA4SM-AVTB project and extends the service to the validation of high-resolution soil moisture satellite products. To achieve general acceptance, QA4SM endorses maximum transparency, traceability, and reproducibility. This is facilitated through the use of the latest community-based validation best practices, endorsed by the Committee on Earth Observation Satellites (CEOS) and the Global Climate Observing System (GCOS), the use of open source software, algorithms and reference data (e.g. from the International Soil Moisture Network and ERA5 reanalysis). The QA4SM online service is available at http://qa4sm.at. It is now integrated into ESA's Fiducial Reference Measurement System and is further evolved in the FRM4SM ESA project.

QA4SM brings together methodologies and protocols used for the validation and quality control of soil moisture data products and provides users with traceable validation results. The Quality Assurance for Soil Moisture (QA4SM) service provides the user with:

1. an easy-to-use interface for comparing satellite soil moisture data against land surface models and in-situ data from the international soil moisture network.

2. a traceable, standardized, reproducible and consistent methodology for all comparisons.

3. filtering, scaling and evaluation options to assess the impact of selected parameters on the validation results.

4. sharable and traceable validation results in netCDF format and visualisations in graphs and maps.