Figure 1
Location and view of Soontaga flux tower.
Figure 2
(A) Top-of-Atmosphere shortwave reflectance composite (ETM+ Bands 7–4–2) over Soontaga area with the derived gamma variance of the surface albedo (B).
Table 1
Major parameters and values used in the BEPS model or input preparation.
| Input parameters | Values | Reference |
|---|---|---|
| Clumping Index | 0.69 | For Soontaga site according to the global clumping index map by He et al. (2012), RSE |
| Scale factor for LAI (500 m pixel size) | 0.1 | MODIS product MCD15A3H.006 (USGS, 2021) |
Figure 3
GPP trajectories for 2016 (A), 2017 (B), 2018 (C), 2019 (D).
Table 2
Annual total GPP from tower-based observations (with uncertainty values), BEPS model, and percentage difference.
| Year | GPP Tower (g C m−2) | GPP BEPS (g C m−2) | Difference (%) |
|---|---|---|---|
| 2016 | 1447±16 | 1175 | −23.12 |
| 2017 | 1166±6 | 1214 | 3.96 |
| 2018 | 1143±38 | 1345 | 14.96 |
| 2019 | 1288±2 | 1293 | 0.33 |
Table 3
Local weather conditions at Soontaga study site.
| Year | Average temperature of each year (°C) | Annual total precipitation (cm) | Warm/cold | Dry/wet |
|---|---|---|---|---|
| 2016 | 7.57 | 47.40 | Cold | Wet |
| 2017 | 7.09 | 49.52 | Cold | Wet |
| 2018 | 8.18 | 32.90 | Warm | Dry |
| 2019 | 8.29 | 59.07 | Warm | Wet |
Figure 4
Regressions between BEPS and tower daily GPP estimates in 2016 (A), 2017 (B), 2018 (C), 2019 (D). There are two regression lines in (A), one shows regession including GPP estimates with the missing meteorological data (empty circles; purple line), another is for the days without the missing values (full circles; red line).
Figure 5
Impact of precipitation, temperature and LAI inputs on BEPS GPP in 2016 (A), 2017 (B), s2018 (C), 2019 (D).
Figure 6
Eddy covariance tower measurements and BEPS model retrievals with constant LAI input values of 1 and 2 in 2019.