Table 8.
Performance comparison of factory and our own linear calibrations for all five tested sensors in saline conditions: average AD (vol %) and RMSE values (vol %).
| Factory Linear Calibration | Own Linear Calibration | ||||||
|---|---|---|---|---|---|---|---|
| Sensor Type | Material | Packing | Salinity 1 | Average AD (vol %) | RMSE (vol %) | Average AD (vol %) | RMSE (vol %) |
| ECH2O TE | Sand | Compact | 1st round | 0.64 | 0.72 | 0.42 | 0.62 |
| ECH2O EC-5 | Sand | Compact | 1st round | 2.81 | 2.90 | 0.92 | 0.95 |
| ECH2O EC-10 | Sand | Compact | 1st round | 4.03 | 4.42 | 10.73 | 11.51 |
| ECH2O EC-20 | Sand | Compact | 1st round | 4.09 | 4.49 | 12.95 | 13.66 |
| ThetaProbe | Sand | Compact | 1st round | 1.32 | 1.63 | 2.00 | 2.03 |
| ECH2O TE | Sand | Compact | 2nd round | 1.82 | 1.93 | 0.93 | 1.07 |
| ECH2O EC-5 | Sand | Compact | 2nd round | 1.75 | 2.37 | 1.41 | 1.43 |
| ECH2O EC-10 | Sand | Compact | 2nd round | 11.11 | 12.23 | 20.55 | 21.43 |
| ECH2O EC-20 | Sand | Compact | 2nd round | 10.36 | 11.22 | 21.25 | 21.79 |
| ThetaProbe | Sand | Compact | 2nd round | 3.79 | 4.31 | 4.65 | 4.79 |
| ECH2O TE | Sand | Compact | 3rd round | 4.63 | 4.71 | 3.49 | 3.52 |
| ECH2O EC-5 | Sand | Compact | 3rd round | 1.80 | 1.97 | 2.53 | 2.91 |
| ECH2O EC-10 | Sand | Compact | 3rd round | 16.74 | 17.12 | 26.62 | 26.87 |
| ECH2O EC-20 | Sand | Compact | 3rd round | 16.06 | 16.45 | 27.39 | 27.61 |
| ThetaProbe | Sand | Compact | 3rd round | 7.58 | 7.64 | 7.70 | 7.71 |
1 Increasing salinity level due to repeated saline water application on the sand material; 1st round = the initially dry sand was wetted by saline water, then the water was evaporated (salt remained) and new wetting with saline water started = 2nd round, etc.