TY  - JOUR
AU  - Dimitrov, M.
AU  - Vanderborght, J.
AU  - Kostov, K. G.
AU  - Jadoon, K. Z.
AU  - Weihermüller, L.
AU  - Jackson, T. J.
AU  - Bindlish, R.
AU  - Pachepsky, Y.
AU  - Schwank, M.
AU  - Vereecken, H.
TI  - Soil Hydraulic Parameters and Surface Soil Moisture of a Tilled Bare Soil Plot Inversely Derived from L-Band Brightness Temperatures
JO  - Vadose zone journal
VL  - 13
IS  - 1
SN  - 1539-1663
CY  - Madison, Wis.
PB  - SSSA
M1  - FZJ-2014-00432
SP  - 1-18
PY  - 2014
AB  - L-band radiometers can be used to remotely monitor the microwave brightness temperature of land surfaces. We investigated how soil hydraulic properties and soil moisture contents of a bare soil plot can be inferred from L-band brightness temperatures using a coupled inversion approach.We coupled a radiative transfer model and a soil hydrologic model (HYDRUS 1D) with an optimization routine to derive soil hydraulic parameters, surface roughness, and soil moisture of a tilled bare soil plot using measured brightness temperatures at 1.4 GHz (L-band), rainfall, and potential soil evaporation. The robustness of the approach was evaluated using five 28-d data sets representing different meteorological conditions. We considered two soil hydraulic property models: the unimodal Mualem–van Genuchten and the bimodal model of Durner. Microwave radiative transfer was modeled by three different approaches: the Fresnel equation with depth-averaged dielectric permittivity of either 2- or 5-cm-thick surface layers and a coherent radiative transfer model (CRTM) that accounts for vertical gradients in dielectric permittivity. Brightness temperatures simulated by the CRTM and the 2-cm-layer Fresnel model fitted well to the measured ones. L-band brightness temperatures are therefore related to the dielectric permittivity and soil moisture in a 2-cm-thick surface layer. The surface roughness parameter that was derived from brightness temperatures using inverse modeling was similar to direct estimates from laser profiler measurements. The laboratory-derived water retention curve was bimodal and could be retrieved consistently for the different periods from brightness temperatures using inverse modeling. A unimodal soil hydraulic property function underestimated the hydraulic conductivity near saturation. Surface soil moisture contents simulated using retrieved soil hydraulic parameters were compared with in situ measurements. Depth-specific calibration relations were essential to derive soil moisture from near-surface installed sensors.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000330971700007
DO  - DOI:10.2136/vzj2013.04.0075
UR  - https://juser.fz-juelich.de/record/150362
ER  -