4. 4
2. In-situ Rainfall data
β’ k is an empirical factor to
indicate the decay effect from
the rainfall (0.85 and 0.98 )
β’ Pt-i is the precipitation value
at ith days before day of t
Antecedent Precipitation Index
6. 6
3. Random Forest Regression Model:
Two Steps Downscaling
c) 16cm & 1km resolution DEM
a) Flowchart of RF regression model
b) Two steps downscaling
7. 7
3. RF Regression Model:
Coarse Resolution (1km & 30m) Data
Datasets (Sensor) Variables Spatial resolution Temporal resolution Duration
Sentinel-1 C-SAR
Surface soil moisture
(SSM)
1km Daily 2015-2019
MODIS
Land surface
temperature (LST)
1km Daily 2015-2019
MODIS
Normalized difference
vegetation (NDVI)
1km
10 days 2015-2019
SRTM
Digital Elevation Model
(DEM)
30m / /
LANDSAT-8 RED, GREEN BANDS 30m 16 days 2015-2019
LANDSAT-8 TIR BANDS 30m 16 days 2015-2019
8. 8
3. RF Regression Model: MODEL I
1kmβ30m
Feature: API, Importance: 0.56
LST, Importance: 0.27
NDVI, Importance: 0.10
DEM, Importance: 0.07
RMSE: 11.17 [saturation degree]
r2: 0.84
Pearson correlation coefficient: 0.91
a) RF Regression Model I Test Results
b) Evaluation of the Estimated SM Time Series
SM
SM
9. 9
3. RF Regression Model: MODEL II
30mβ16cm
a) RF Regression Model II Test Results b) Validation of the Estimated SM c) Estimated SM map (14-June-2019)
30m Soil moisture
10. 10
3. 5year average map of 30m predicted SSM
5year-average 30m SSM (30km*30km) MFC2 and SoilNet
MFC2
DEM 30km*30km
13. 13
4. Scaling characteristics: Variances Time series
1km sentinel SSM product Predicted 30m SSM product
Same Area: 30km*30km
14. 14
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Reference
15. Appendix 1: LANDSAT-8: From TIR to LST
β’ STEP 1:
πΉππΆ =
ππ·ππΌ β ππ·ππΌπ
ππ·ππΌπ£ + ππ·ππΌπ
NDVI values of full vegetation cover and
bare soil.
β’ STEP 2:
Land surface emissivity π retrieval:
ππ πΉππΆ = 0 β π
= 0.979 β 0.046 β πππππ4
ππ 0 < πΉππΆ < 1 β π
= 0.971(1 β πΉππΆ) + 0.987 β πΉππΆ
ππ πΉππΆ = 1 β π = 0.99
β’ STEP 3
ππ = [
π2
π ln{
π1
π5[
[π(
π1
(π
π2
π ) β 1
) + (1 β π)πΏπ] β (1 β π)πΏπ
π
]
+ 1}
β’ πΏπ is the down-welling atmospheric radiance.
β’ π is the effective band wavelength,
β’ T is the brightness temperature (K),
β’ π1 = 1.19104 Γ 108
πππ4
πβ2
π πβ1
β’ π2 = 14387.7πππΎ
β’ K1=774.8853
β’ K2=1321.0789
β’ π is the land surface emissivity.
15
16. Appendix 2: Example map of LST
16
Presence of clouds may limit the extents of
the higher resolution LST maps
lst1: 1km MODIS LST (averaged of 13:30 and 01:30)
lst2: 30m LANDSAT LST (daytime)
17. Appendix 3: Example map of NDVI
β’ LANDSAT8 Band 4 (red) & 5 (Nir) (Top of atmosphere reflectance)β Atmosphere correction (bottom of
atmosphere reflectance) β NDVI ori β Interpolation (with limit)β S-G filter β NDVI (30m)
β’ MODIS 1km NDVI β S-G filter
17
NDVI
ndvi1: 1km MODIS NDVI
ndvi2: 30m LANDSAT NDVI