Portales New Mexico
Warning: This codes does not currently check for equipment changes. This makes a big difference at P038 - you should not compute VWC across equipment changes. This site’s equipment was upgraded in March 2021.
Station Name: p038
Location: Portales, NM, USA
Latitude: 34.14726 degrees
Longitude: -103.40734 degrees
Height: 1212.982 meters
P038 was a PBO site and a PBO H2O site. The data from 2017 will be analyzed here as a test case. We will start by analyzing the data using the normal reflector height (GNSS-IR) processing. Then we will use those results to run the soil moisture code.
Step 1: GNSS-IR
Begin by generating the SNR files. Although typically PBO sites do not have L2C data in their low-rate RINEX files, UNAVCO is providing these data in the “special” archive section so that people can test out this code.
rinex2snr p038 2017 1 -doy_end 365 -archive special
If you want to remind yourself why the L2C data are superior to the L1 data recorded for this receiver, use
We only need the L2C data, so have set the parameter accordingly.
gnssir_input p038 -l2c true
The json file is saved at $REFL_CODE/input/p038.json
Now we run
gnssir. This will be needed for estimate a priori reflector heights for the soil moisture code.
gnssir p038 2017 1 -doy_end 365
Step 2: Soil Moisture
Please read the soil moisture user manual. It is very short and has a lot of tips that will save you time.
We need a list of satellite tracks to use:
vwc_input p038 2017
This creates a file that is stored in $REFL_CODE/input/p038_phaseRH.txt
Now we estimate the phase for each satellite track on each day:
phase p038 2017 1 -doy_end 365
Finally, convert the phase to volumetric water content:
vwc p038 2017
Phase results plotted in geographic coordinates:
Daily average phase:
By default the final VWC results go to:
Thank you to Naoya Kadota for test driving this use case.
Kristine M. Larson September 14, 2022