Quality flags are meant to work as an indicator for the reliability of the data. In order to provide harmonized quality measures for each soil moisture observation, originating from different data providers, sophisticated quality checks were developed by the ISMN team. Each soil moisture measurement has to go through several automated quality check procedures. Finally, a quality flag (or combination of flags) is attached to each observation, which is automatically included in your download file.
You can find a list of our quality flags and their meaning at the Quality Flags
page within the Data Access
section of our homepage. For a detailed explanation and description of the methodology have a look at our publication