Notes on the protocols
 
The 30 x 30 m plot sampling is what most have used, with probing in the 4 corners and the center.  It really doesn't take that long to do that, GPS the center and then write down the ecosystem and sample depth of organic soil. If they can record the profile of live moss depth, dead moss depth, etc it should take them less than 30 min per site and that allows us to determine the best calibration for the probe (for organic soils). ALT could also be sampled in the 30 x 30 m plot (landsat pixel). What will be time consuming is if profile soil moisture is measured, which requires digging.
 
In a pinch, we can forgo that and validate our retrievals just with ALT and surface soil moisture. If these two quantities check out, then we may be able to justify that the profile soil moisture retrieval is reliable also. If time is of concern, skip digging and measure ALT and surface soil moisture at the corners and center.  This should take about 30 minutes.
 
Laura's protocol has two options, one where you insert the probe vertically and another where the probe is at an angle. Mahta's suggestion is to use the probe at an angle so that it's closer to horizontal than vertical. This way, we get a good reading of the "surface" as opposed to an integration along the vertical length of the probe. The vertical configuration makes the comparison of probe measurements with radar retrievals a little ambiguous.
 
Questions about the ALT protocol should be addressed to Kevin Schaefer (kevin.schaefer@colorado.edu). Questions about the soil moisture protocol should be addressed to Laura Bourgeau-Chavez (lchavez@mtu.edu) and Mahta Moghaddam (mahta@usc.edu).

Version: 4 August 2022