Investigating Correlations and the Validation of SMAP-Sentinel L2 and In Situ Soil Moisture in Thailand
Abstract
:1. Introduction
2. Materials and Methods
2.1. Remote Sensing Soil Moisture
2.2. In Situ Soil-Moisture Monitoring
2.3. Laboratory Testing of Soil
2.4. Basic Soil Properties
2.5. Soil-Moisture Sensor Calibration
2.6. Hydraulic and Thermal Properties
2.7. Soil–Water Retention Curves
3. Results
3.1. Correlations and Calibration of SMAP-Sentinel and In Situ Soil Moisture
3.1.1. Effect of the Temporal Variation in Soil Moisture
3.1.2. Linear Correlation Coefficients and Soil Properties
3.1.3. Upscaling of SMAP, In Situ Soil Moisture and Validation for Croplands
4. Discussion and Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
List of Notations
SMAP | Soil Moisture Active/Passive |
θ | In situ volumetric water content |
SSM | Surface soil moisture |
Volume of soil water | |
Total volume of soil | |
Sensor reading (mA) | |
, | Fitting parameters for water content–voltage sensor calibration from linear regression |
, | Multiple linear regression parameters for sensor calibration based on physical properties for |
, | Multiple linear regressions parameters for sensor calibration based on physical properties for |
Soil physical properties used in multiple linear regressions | |
Saturated volumetric water content | |
Residual volumetric water content | |
Soil suction | |
Van Genuchten’s fitting parameter for soil–water retention curves | |
M, C | Linear regression fitting parameters between θ and SSM, based on 1-month average values |
, , …, | Multiple linear regression parameters for based on physical properties |
Multiple linear regression parameters for based on physical properties |
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No. | Station Name | Province | Latitude | Longitude | Land Use 1 | Geology 2 | Geography | Elevation (AMSL) | Average Annual Rainfall 3 |
---|---|---|---|---|---|---|---|---|---|
1 | KKCN | Phetchaburi | 12.8723 | 99.6835 | Perennial plant | Sedimentary and metamorphic | Plain at the foot of hilly terrains | 64 m | 983.0 mm |
2 | VLGE49 | Phetchabun | 15.61636 | 101.023 | Field crop | Quaternary sediment | Undulating plain | 96 m | 1210.0 mm |
3 | HNKA | Chai Nat | 14.9696 | 100.0104 | Rice paddy | Quaternary alluvial sediment | Flood plain | 13 m | 1010.8 mm |
4 | WGYG | Saraburi | 14.8481 | 101.1459 | Field crop | Sedimentary rock | Plain | 93 m | 1185.2 mm |
5 | VLGE50 | Prachinburi | 14.0426 | 101.7204 | Rice paddy | Quaternary alluvial sediment | Alluvial plain | 27 m | 1762.4 mm |
6 | NMUB | Nan | 18.48421 | 100.93071 | Forest | Sedimentary rock | Undulating plain | 333 m | 1238.9 mm |
7 | PAII | Mae Hong Son | 19.37012 | 98.39309 | Fruit trees | Granitic | Plain between complex mountain ranges | 776 m | 1315.8 mm |
8 | BNKE | Nakhon Phanom | 16.90888 | 104.6187 | Rice paddy | Sedimentary and metamorphic | Plain | 153 m | 2328.0 mm |
9 | THAT | Surin | 15.31667 | 103.9355 | Urban | Sedimentary rock | Plain | 128 m | 1445.3 mm |
10 | SWR036 | Satun | 7.08837 | 100.002 | Perennial plant | Igneous | Basin surrounded by hills | 110 m | 2386.0 mm |
No. | Station Name | Depth (cm) | Atterberg Limits | Grain Size Distribution (%) | Porosity | Organic Content (g/kg) | Specific Gravity | Soil Type (Unified Soil Classification System) | |||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Liquid Limits (%) | Plastic Limits (%) | Plasticity Index, PI | Gravel | Sand | Silt | Clay | |||||||
1 | KKCN | 0–50 | 44.70 | 24.62 | 20.08 | 4.24 | 27.90 | 21.04 | 46.83 | 0.41 | 20.0 | 2.64 | CL |
50–100 | 52.80 | 30.83 | 21.97 | 0.71 | 23.16 | 26.22 | 49.91 | 0.47 | 5.8 | 2.41 | CH | ||
2 | VLGE49 | 0–100 | 43.82 | 25.12 | 18.70 | 0.88 | 37.19 | 2.03 | 59.90 | 0.54 | 19.0 | 2.70 | CL |
3 | HNKA | 0–10 | 33.40 | 18.52 | 14.88 | 11.70 | 66.56 | 8.29 | 13.45 | 0.39 | 10.0 | 2.59 | SC |
10–40 | 24.10 | 14.51 | 9.59 | 11.39 | 43.52 | 23.29 | 21.81 | 0.37 | 6.8 | 2.52 | SM | ||
40–100 | NP | NP | NP | 2.05 | 63.01 | 16.87 | 18.07 | 0.49 | 4.9 | 2.63 | SC | ||
4 | WGYG | 0–50 | 62.00 | 48.38 | 21.63 | 7.17 | 40.11 | 41.49 | 11.23 | 0.57 | 30.0 | 2.68 | MH |
50–100 | 39.80 | 29.03 | 10.77 | 4.55 | 44.31 | 45.44 | 5.70 | 0.52 | 5.8 | 2.64 | ML | ||
5 | VLGE50 | 0–20 | 25.90 | 20.16 | 5.74 | 2.03 | 45.73 | 2.15 | 50.09 | 0.45 | 11.0 | 2.69 | CL |
20–100 | 29.70 | 20.79 | 8.91 | 3.83 | 39.61 | 5.46 | 51.10 | 0.38 | 1.8 | 2.70 | CL | ||
6 | NMUB | 0–100 | NP | NP | NP | 17.53 | 32.04 | 40.43 | 10.00 | 0.58 | 17.0 | 2.65 | ML |
7 | PAII | 0–10 | 39.00 | 28.91 | 10.09 | 5.76 | 43.42 | 44.32 | 6.50 | 0.68 | 35.0 | 2.67 | ML |
10–100 | 64.30 | 26.39 | 37.91 | 0.22 | 43.57 | 4.20 | 52.01 | 0.55 | 3.5 | 2.71 | CH | ||
8 | BNKE | 0–50 | NP | NP | NP | 18.89 | 46.24 | 22.26 | 12.61 | 0.41 | 15.0 | 2.60 | SM |
50–70 | NP | NP | NP | 14.92 | 50.03 | 22.13 | 12.92 | 0.36 | 5.8 | 2.52 | SM | ||
70–100 | 24.20 | 16.75 | 7.45 | 7.75 | 48.92 | 20.80 | 22.53 | 0.38 | 5.3 | 2.62 | SM | ||
9 | THAT | 0–10 | NP | NP | NP | 8.19 | 55.32 | 15.06 | 21.44 | 0.36 | 10.0 | 2.60 | SC |
10–100 | NP | NP | NP | 0.07 | 70.21 | 13.97 | 15.74 | 0.35 | 0.8 | 2.49 | SM | ||
10 | SWR036 | 0–10 | NP | NP | NP | 0.25 | 70.04 | 16.05 | 13.66 | 0.52 | 15.0 | 2.55 | SM |
10–40 | NP | NP | NP | 1.46 | 70.41 | 12.92 | 15.22 | 0.42 | 8.0 | 2.48 | SC | ||
40–100 | NP | NP | NP | 7.51 | 82.25 | 4.66 | 5.57 | 0.44 | 1.8 | 2.60 | SP |
No. | Station Name | Soil Unit * | Depth (cm) | Sensor Calibration Coefficients | Hydraulic Conductivity, k, cm/s | Thermal Conductivity, λ, W/(m·K) | ||
---|---|---|---|---|---|---|---|---|
a | b | R2 | ||||||
1 | KKCN | U | 0–50 | 3.9346 | −20.638 | 0.9839 | 9.44 × 10−5 | 1.76 |
L | 50–100 | 5.5088 | −42.002 | 0.9812 | 1.32 × 10−4 | 2.34 | ||
2 | VLGE49 | - | 0–100 | 4.9995 | −30.271 | 0.9822 | 3.31 × 10−5 | 1.68 |
3 | HNKA | U | 0–10 | 3.6222 | −22.539 | 0.9802 | 1.80 × 10−7 | 1.41 |
M | 10–40 | 4.1060 | −26.655 | 0.9872 | 1.18 × 10−7 | 1.76 | ||
L | 40–100 | 3.6185 | −19.873 | 0.9940 | 5.83 × 10−4 | 2.01 | ||
4 | WGYG | U | 0–50 | 4.3506 | −26.233 | 0.9946 | 2.56 × 10−4 | 1.44 |
L | 50–100 | 7.6092 | −68.035 | 0.9847 | 1.68 × 10−4 | 1.26 | ||
5 | VLGE50 | U | 0–20 | 4.4931 | −27.202 | 0.9911 | 1.02 × 10−7 | 1.44 |
L | 20–100 | 3.5044 | −18.562 | 0.9915 | 2.61 × 10−7 | 2.01 | ||
6 | NMUB | - | 0–100 | 6.8022 | −56.189 | 0.9910 | 2.20 × 10−3 | 1.31 |
7 | PAII | U | 0–10 | 8.2213 | −63.759 | 0.9846 | 1.33 × 10−3 | 2.63 |
L | 10–100 | 6.1297 | −38.391 | 0.9911 | 2.80 × 10−6 | 1.13 | ||
8 | BNKE | U | 0–50 | 4.8077 | −37.689 | 0.9947 | 8.04 × 10−5 | 1.48 |
M | 50–70 | 3.5852 | −22.114 | 0.9921 | 2.56 × 10−6 | 1.67 | ||
L | 70–100 | 4.2354 | −29.708 | 0.9911 | 4.21 × 10−7 | 2.51 | ||
9 | THAT | U | 0–10 | 3.5023 | −24.270 | 0.9940 | 1.62 × 10−6 | 2.87 |
L | 10–100 | 3.4499 | −22.674 | 0.9872 | 1.66 × 10−5 | 2.89 | ||
10 | SWR036 | U | 0–10 | 5.4454 | −38.234 | 0.9944 | 1.93 × 10−3 | 0.88 |
M | 10–40 | 3.8002 | −22.982 | 0.9998 | 4.32 × 10−3 | 2.34 | ||
L | 40–100 | 5.9551 | −39.924 | 0.9938 | 4.20 × 10−3 | 1.26 |
1598.835 | −0.000552 | −15.971 | −16.009 | −15.985 | −16.007 | 14.960 | −0.0608 |
−16,579.396 | 0.123 | 165.669 | 166.105 | 165.639 | 166.058 | −132.139 | 0.727 |
No. | Station Name | Soil Unit * | Depth (cm) | Van Genuchten Parameter | |||||
---|---|---|---|---|---|---|---|---|---|
(%) | (%) | p (kPa−1) | n | m | R2 | ||||
1 | KKCN | U | 0–50 | 41 | 10 | 0.072 | 0.442 | 1.066 | 0.958 |
L | 50–100 | 47 | 10 | 0.496 | 0.560 | 1.026 | 0.960 | ||
2 | VLGE49 | - | 0–100 | 54 | 20 | 0.00470 | 0.318 | 1.059 | 0.985 |
3 | HNKA | U | 0–10 | 39 | 7 | 0.0524 | 0.532 | 1.590 | 0.948 |
M | 10–40 | 37 | 3 | 0.00905 | 0.512 | 1.350 | 0.950 | ||
L | 40–100 | 49 | 2 | 0.0364 | 0.413 | 1.105 | 0.973 | ||
4 | WGYG | U | 0–50 | 57 | 19 | 0.0211 | 0.378 | 1.345 | 0.969 |
L | 50–100 | 52 | 5 | 0.0258 | 0.428 | 1.207 | 0.954 | ||
5 | VLGE50 | U | 0–20 | 45 | 10 | 0.00216 | 0.356 | 1.114 | 0.962 |
L | 20–100 | 38 | 12 | 0.0189 | 0.394 | 1.168 | 0.957 | ||
6 | NMUB | - | 0–100 | 31 | 2 | 0.000843 | 0.484 | 1.504 | 0.975 |
7 | PAII | U | 0–10 | 31 | 15 | 0.0113 | 0.906 | 1.501 | 0.982 |
L | 10–100 | 46 | 18 | 0.0370 | 0.913 | 0.318 | 0.936 | ||
8 | BNKE | U | 0–50 | 30 | 17 | 0.00903 | 0.691 | 1.758 | 0.937 |
M | 50–70 | 26 | 6 | 0.158 | 0.938 | 0.309 | 0.996 | ||
L | 70–100 | 30 | 9 | 0.0806 | 1.075 | 0.308 | 0.981 | ||
9 | THAT | U | 0–10 | 36 | 6 | 0.360 | 4.556 | 0.0670 | 0.984 |
L | 10–100 | 35 | 0 | 0.00311 | 0.380 | 1.892 | 0.971 | ||
10 | SWR036 | U | 0–10 | 17 | 2 | 0.164 | 20.779 | 0.0181 | 0.966 |
M | 10–40 | 30 | 0 | 0.00000133 | 0.347 | 17.014 | 0.989 | ||
L | 40–100 | 25 | 7 | 0.115 | 1.990 | 0.162 | 0.967 |
No. | 1 | 2 | 3 | 4 | 5 | ||||
Station | KKCN | VLGE49 | HNKA | WGYG | VLGE50 | ||||
Depth (cm) | all | 10 | 30 | 10 | 100 | 10 | 10 | 30 | 100 |
M | NR | 0.3207 | 0.2883 | 0.2387 | 0.3428 | 0.1283 | 0.364 | 0.3451 | 0.2059 |
C | NR | 12.247 | 42.324 | 13.493 | 19.155 | 42.016 | 24.438 | 21.165 | 29.807 |
R2 | NR | 0.4385 | 0.3943 | 0.2086 | 0.4134 | 0.1756 | 0.4971 | 0.5471 | 0.5814 |
No. | 6 | 7 | 8 | 9 | 10 | ||||||
Station | NMUB | PAII | BNKE | THAT | SWR036 | ||||||
Depth (cm) | 10 | 30 | 60 | all | 10 | 30 | 60 | 100 | 30 | 100 | all |
M | 0.4217 | 1.1006 | 0.9325 | NR | 0.4748 | 0.6607 | 0.3699 | 0.3497 | 0.255 | 0.3873 | NR |
C | 21.306 | 1.5069 | 0.4633 | NR | 9.0514 | 2.7021 | 12.625 | 21.448 | 5.6962 | 4.0059 | NR |
R2 | 0.1296 | 0.5333 | 0.5378 | NR | 0.5247 | 0.6376 | 0.4906 | 0.4722 | 0.2969 | 0.3345 | NR |
−400.298 | −0.00987 | 4.0132 | 4.0052 | 4.0042 | 4.0083 | 0.1167 | 0.0006060 |
−219,718.912 | 0.083 | 2196.216 | 2197.531 | 2198.317 | 2197.613 | −54.224 | 0.377 |
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Jotisankasa, A.; Torsri, K.; Supavetch, S.; Sirirodwattanakool, K.; Thonglert, N.; Sawangwattanaphaibun, R.; Faikrua, A.; Peangta, P.; Akaranee, J. Investigating Correlations and the Validation of SMAP-Sentinel L2 and In Situ Soil Moisture in Thailand. Sensors 2023, 23, 8828. https://doi.org/10.3390/s23218828
Jotisankasa A, Torsri K, Supavetch S, Sirirodwattanakool K, Thonglert N, Sawangwattanaphaibun R, Faikrua A, Peangta P, Akaranee J. Investigating Correlations and the Validation of SMAP-Sentinel L2 and In Situ Soil Moisture in Thailand. Sensors. 2023; 23(21):8828. https://doi.org/10.3390/s23218828
Chicago/Turabian StyleJotisankasa, Apiniti, Kritanai Torsri, Soravis Supavetch, Kajornsak Sirirodwattanakool, Nuttasit Thonglert, Rati Sawangwattanaphaibun, Apiwat Faikrua, Pattarapoom Peangta, and Jakrapop Akaranee. 2023. "Investigating Correlations and the Validation of SMAP-Sentinel L2 and In Situ Soil Moisture in Thailand" Sensors 23, no. 21: 8828. https://doi.org/10.3390/s23218828
APA StyleJotisankasa, A., Torsri, K., Supavetch, S., Sirirodwattanakool, K., Thonglert, N., Sawangwattanaphaibun, R., Faikrua, A., Peangta, P., & Akaranee, J. (2023). Investigating Correlations and the Validation of SMAP-Sentinel L2 and In Situ Soil Moisture in Thailand. Sensors, 23(21), 8828. https://doi.org/10.3390/s23218828