Effect of moisture on scattering (by Ulaby, Moore, Fung, 82). SMOOTH. SMC=34
%. SMC=5%. ROUGH. SMC=38%. SMC=9%. Ground based mesurements ...
APPLICATION TO MONITORING OF VARIABLES: SOIL MOISTURE, VEGETATION BIOMASS, WETLAND PROPERTIES by : P. Ferrazzoli Tor Vergata University Roma, Italy
[email protected]
MAIN PHYSICAL PROCESSES
1
BARE SOILS Approximation: half-spaces with rough interfaces
εo
ε
Surface profile
Autocorrelation function
BARE SOILS Important for applications: εr is stongly influenced by moisture. Real and imaginary parts of soil permittivity as a function of volumetric soil moisture content (SMC) at 1.4 GHz (L band) Measured values (by Ulaby, Moore, Fung, 82)
2
BARE SOILS Effect of moisture on scattering (by Ulaby, Moore, Fung, 82) Ground based mesurements (U.S.A.)
SMOOTH
σ° vs. angle, 4.25 GHz (C band)
SMC=34% SMC=5% ROUGH SMC=38% SMC=9%
BARE SOILS Effect of roughness on scattering Ground based mesurements (U.S.A.), σ° vs. angle, (by Ulaby, Moore, Fung, 86) 1.1 GHz
4.25 GHz
7.25 GHz
ROUGH
SMOOTH
3
GENERAL PROPERTIES OF EMISSION FROM NATURAL MEDIA Emissivity of flat surfaces vs. angle (computations) (by Ulaby, Moore, Fung, 82) Increasing moisture,
ε increases, Reflectivity increases, Emissivity decreases
BARE SOILS Emissivity vs. angle, L band (1.4 GHz) Ground based measurements (by Ulaby, Moore, Fung, 82)
moisture
Constant roughness, Moisture variations
4
BARE SOILS Emissivity vs. angle, L band (1.4 GHz) Ground based measurements (by Ulaby, Moore, Fung, 82)
Constant moisture, Roughness variations
roughness
BARE AND VEGETATED SOILS Airborne measurements (AIRSAR), L band, HH polarization, θ=35° Site: Montespertoli (Italy). σ° vs. SMC, average field values (by Macelloni et al., 1999) Several bare and vegetated fields. Effects of roughness and vegetation make correlation very poor.
5
BARE AND VEGETATED SOILS Airborne measurements (AIRSAR), L band, HH polarization, θ=20° Site: Montespertoli (Italy). σ° vs. SMC, average field values (by Baronti et al., 1995)
Several bare and vegetated fields.
bare
Correlation is improved by using lower angles and separating bare fields by vegetated fields. vegetated
BARE AND VEGETATED SOILS Airborne measurements (AIRSAR), L band, HH pol.,θ=25°, θ=35° Site: Montespertoli (Italy). σ° vs. SMC, average field values (by Macelloni et al., 1999) Bare fields and vegetated fields with LAI4 kg/m^2 2 kg/m^2
