Environmental and Biophysical Effects of the Bowen Ratio over Typical Farmland Ecosystems in the Loess Plateau
Abstract
:1. Introduction
2. Materials and Methods
2.1. Site Description
2.2. Observation Method and Data Processing
2.3. Energy Balance
2.4. Soil Heat Flux Correction
2.5. Bowen Ratio
2.6. Overall Land Surface Parameters
3. Results
3.1. Environmental Factor Variations
3.2. Energy Balance Characteristics
3.3. Diurnal Cycle and Seasonal Variation in Energy Flux
3.4. Bowen Ratio Variation
3.5. Environmental and Ecological Controls on Bowen Ratio
4. Discussion
4.1. Bowen Ratio Variation
4.2. Influence of Environmental and Ecological Factors on the Bowen Ratio
4.3. Biometeorological Controls on the Bowen Ratio
5. Conclusions
Author Contributions
Funding
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Instrument | Type | Installation Height | |
---|---|---|---|
Dingxi | Qingyang | ||
Open Path CO2/H2O Gas Analyzer | Li-7500, Li-Cor (Lincoln, NE, USA) | 2.5 m | 3 m |
Three-dimensional (3D) sonic anemometer | CSAT-3, Campbell (Logan, UT, USA) | 2.5 m | 3 m |
Temperature and relative humidity probe | HMP45C-L, Vaisala (Vantaa, Finland) | 1, 2, 4, 10, and 16 m | 2, 4, 8, and 18 m |
Net radiometer | CNR4, Kipp and Zoned (Delft, The Netherlands) | 1.5 m | 1.5 m |
Self-calibrating heat flux sensor | HFP01SC-L50, Hukseflux (Delft, The Netherlands) | 2, 5, and 10 cm | 1, 2.5 and 5 cm |
Soil temperature profile sensor | STP01-L50, Hukseflux | 0, 5, 10, 20, 40, 50, and 80 cm | 0, 5, 10, 20, 40, 60, and 90 cm |
Water content reflectometer | CS616-L, Campbell | 5, 10, 20, 40, 50, and 80 cm | 5, 10, 20, 40, 60, and 90 cm |
Site | Midday | Night | All Day | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Sample Numbers | OLS | EBR | Sample Numbers | OLS | EBR | Sample Numbers | OLS | EBR | ||||
Slope | R2 | Slope | R2 | Slope | R2 | |||||||
Dingxi | 10,516 | 0.65 | 0.68 | 0.89 | 11,190 | 0.18 | 0.05 | 0.03 | 40,350 | 0.76 | 0.81 | 0.68 |
Qingyang | 5149 | 0.71 | 0.71 | 0.81 | 7773 | 0.11 | 0.05 | 0.49 | 24,064 | 0.73 | 0.85 | 0.60 |
Site | Rn (W/m2) | LE (W/m2) | H (W/m2) | G (W/m2) | ||||
---|---|---|---|---|---|---|---|---|
Peak | Mean | Peak | Mean | Peak | Mean | Peak | Mean | |
Dingxi | 334.10 | 67.29 | 64.14 | 20.95 | 120.29 | 28.98 | 157.88 | 6.08 |
Qingyang | 348.37 | 71.74 | 125.83 | 41.41 | 122.32 | 28.50 | 96.93 | 1.62 |
Energy Component (W/m2) | Spring | Summer | Autumn | Winter | |||||
---|---|---|---|---|---|---|---|---|---|
Dingxi | Qingyang | Dingxi | Qingyang | Dingxi | Qingyang | Dingxi | Qingyang | ||
Rn | Peak | 345.02 | 376.71 | 440.16 | 460.16 | 362.38 | 348.03 | 226.45 | 240.88 |
Mean | 67.73 | 77.14 | 109.87 | 119.84 | 78.76 | 75.02 | 25.34 | 26.20 | |
LE | Peak | 39.31 | 82.61 | 103.10 | 169.41 | 101.19 | 168.67 | 22.55 | 21.63 |
Mean | 11.77 | 25.70 | 36.00 | 74.11 | 32.54 | 58.31 | 5.23 | 6.64 | |
H | Peak | 148.75 | 162.54 | 143.10 | 112.81 | 107.21 | 110.68 | 93.27 | 118.66 |
Mean | 34.85 | 34.02 | 41.31 | 30.49 | 28.59 | 25.33 | 17.93 | 21.93 | |
G | Peak | 173.24 | 109.18 | 214.49 | 125.82 | 124.15 | 97.69 | 136.16 | 56.19 |
Mean | 10.34 | 6.68 | 20.07 | 8.67 | 1.24 | −2.29 | −3.29 | −6.94 |
Environmental Factors | Equation Parameters | Dingxi | Qingyang | ||
---|---|---|---|---|---|
Dry | Wet | Dry | Wet | ||
Ts − Ta (℃) | |||||
a | 1.27 | 0.78 | 0.39 | 0.26 | |
b | 0.24 | 0.11 | 0.09 | 0.13 | |
R2 | 0.36 | 0.59 | 0.51 | 0.58 | |
p | <0.01 | <0.01 | <0.01 | <0.01 | |
VPD (kPa) | |||||
a | 2.18 | 0.46 | 0.66 | 0.39 | |
b | 1.62 | 1.45 | 1.76 | 0.65 | |
R2 | 0.29 | 0.38 | 0.44 | 0.22 | |
p | <0.05 | <0.05 | <0.05 | <0.05 | |
Effective precipitation (mm) | |||||
a | 4.25 | 1.27 | 2.16 | 1.05 | |
b | −0.02 | −0.004 | −0.03 | −0.01 | |
R2 | 0.37 | 0.27 | 0.80 | 0.60 | |
p | <0.01 | <0.01 | <0.01 | <0.01 | |
SWC) | |||||
a | 15.23 | 2.49 | 2.48 | 0.12 | |
b | −11.08 | −4.24 | −5.92 | −1.10 | |
R2 | 0.19 | 0.33 | 0.36 | 0.63 | |
p | <0.05 | <0.01 | <0.01 | <0.01 |
Site | Correlation Effect | NDVI | Ta | VPD | SWC |
---|---|---|---|---|---|
Dingxi | Direct | −0.68 | 0.42 | 0.11 | −0.21 |
Indirect | 0.12 | −0.36 | 0.39 | −0.41 | |
Total | −0.57 | 0.06 | 0.51 | −0.63 | |
Qingyang | Direct | 0.33 | −0.90 | 0.54 | −0.35 |
Indirect | −0.84 | 0.37 | −0.26 | −0.01 | |
Total | −0.51 | −0.53 | 0.28 | −0.36 |
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Ren, X.; Zhang, Q.; Yue, P.; Yang, J.; Wang, S. Environmental and Biophysical Effects of the Bowen Ratio over Typical Farmland Ecosystems in the Loess Plateau. Remote Sens. 2022, 14, 1897. https://doi.org/10.3390/rs14081897
Ren X, Zhang Q, Yue P, Yang J, Wang S. Environmental and Biophysical Effects of the Bowen Ratio over Typical Farmland Ecosystems in the Loess Plateau. Remote Sensing. 2022; 14(8):1897. https://doi.org/10.3390/rs14081897
Chicago/Turabian StyleRen, Xueyuan, Qiang Zhang, Ping Yue, Jinhu Yang, and Sheng Wang. 2022. "Environmental and Biophysical Effects of the Bowen Ratio over Typical Farmland Ecosystems in the Loess Plateau" Remote Sensing 14, no. 8: 1897. https://doi.org/10.3390/rs14081897
APA StyleRen, X., Zhang, Q., Yue, P., Yang, J., & Wang, S. (2022). Environmental and Biophysical Effects of the Bowen Ratio over Typical Farmland Ecosystems in the Loess Plateau. Remote Sensing, 14(8), 1897. https://doi.org/10.3390/rs14081897