Data availability
Measurements
Soil moisture measurements are always available for the upper soil layer ( 0 - 10 [cm] depth). Measurements can be integrated up to 2 [m] depth dependent on the network.
In addition to soil moisture, 7 additional variables, stored in the ISMN Database, can be downloaded:
- > soil temperature
- > air temperature
- > precipitation
- > soil suction
- > snow water equivalent
- > snow depth
- > surface temperature
Measuring techniques
Various measuring techniques are used for measuring soil moisture. The most commonly used techniques for in situ samplings are:
- > frequency domain reflectometry (FDR)
- > dielectric properties of soil and water and comprise time domain reflectometry (TDR)
- > capacitance
- > cosmic-ray neutron sensors (CRNS)
Network updates
The various networks and stations fulfill measurements at different temporal sampling intervals (daily average, hourly, several times per hour). Netoworks where only historical data is available provide measurements once or twice a month, or in another irregular pattern. Within the ISMN, integrating data with a temporal resolution of 1 hour is preferred for all applications, including Numerical Weather Prediction (NWP).
- > nrt: almost daily data updates
- > regular: updates are done once a month or in a couple of months
- > irregular: updates done infrequently
The networks could be categorized based on the regularity of their updates: