How do you know that the SWAN estimate of soil moisture is accurate?
The algorithms used to calculate soil moisture balance have been tested in the field, and refined over many years of use in a variety of situations. As long as the parameters that are fed into the model have been set up appropriately, the estimations have been shown to be right on target.
These estimates can be ground-truthed by reference to data coming in from soil moisture probes. If the soil moisture trends from the probe are not reflected by the model, it’s time to check the data inputs – and also time to check if there is an issue with your soil moisture probe.