Usage

• Example 1: Forward modeling of RT models (surface part)
  • 1. Narrative (Examples of forward modeling of available RT models (surface part))
  • 2. Requirements
  • 3. Required imports and helper function
  • 4. Nessesary input parameters
  • 5. Available RT models
• Example 2: Forward modeling of RT model combination (surface + canopy part)
  • 1. Narrative (Examples of different model combination (surface + canopy part))
  • 2. Requirements
  • 3. Required imports
  • 4. Dubois95+SSRT for different incidence angles
  • 5. Oh04+WaterCloud for different incidence angles
• Example 3: Inversion of RT-models
  • 1. Narrative (Inversion of RT-models, soil moisture retrieval from radar backscatter)
  • 2. Requirements
  • 3. Retrieval of soil moisture with RT-model combination Oh92+SSRT
• Example 4: Soil moisture retrieval with real data set
  • 1. Narrative: Inversion of RT-models and Soil Moisture Retrieval
  • 2. Requirements
  • 3. Data Acqusition
  • 4. Harmonize Satellite Data
  • 5. Feature Extraction Get data set for a specific area of interest (field based on shapefile)
  • 6. Inversion

Required input paramter

Surface RT models

Water Could Model (WCM - surface part):

c # empirical fitted soil parameter (calibration constant)
d # empirical fitted soil parameter (indicates the sensitivity of soil moisture on the radar signal)
sm # soil moisture [m³/m³]

Oh model from 1992 (Oh92):

theta # local incidence angle [radians]
k # radar wave number
s # surface roughness [m]
f # frequency [GHz]
eps # dielectric constant of the soil

Oh model from 2004 (Oh04):

theta # local incidence angle [radians]
k # radar wave number
s # surface roughness [m]
f # frequency [GHz]
sm # soil moisture [m³/m³]

Dubois model from 1995 (Dubois95):

theta # local incidence angle [radians]
k # radar wave number
s # surface roughness [m]
f # frequency [GHz]
eps # dielectric constant of the soil

Canopy RT models

Water Cloud Model (WCM - canopy part):

a # empirical fitted vegetation parameter
b # empirical fitted vegetation parameter
V1 # vegetation descriptor e.g., LAI/VWC
V2 # vegetation descriptor e.g., LAI/VWC
theta # local incidence angle [radians]

Single Scattering Radiative Transfer model (SSRT/S²RT):

omega # scattering albedo
d # vegetation height [m]
ke # extinction coefficient [m⁻¹]
scattering assumption: Rayleigh or Turbid Isotropic

Dielectric mixing model (used to translate dielectric constant to soil moisture)

Simplistic approach with with temperature=23°C, bulk density=1.7 g/cm3:

f # frequency [GHz]
clay # clay content of the soil
sand # sand content of the soil

Dobson et al. (1985):

f # frequency [GHz]
clay # Clay content of the soil
sand # Sand content of the soil
bulk # bulk dry density of the soil [g/cm³]