Near surface soil moisture estimation from microwave measurements
Near surface soil moisture estimation from microwave
measurements
L. Bruckler*, H. Witono† and P. Stengel*
†
*
Department of Soil Science, Bogor Agricultural University, J1. Raya Pajajaran, Bogor,
Indonesia
INRA Station de Science du Sol, B.P. 91, Domaine Saint Paul, 84140 Montfavet, France
Abstract
Soil moisture, water potential, and bulk density measurements were performed on a 0.4
ha bare field (27.2% clay, 61.7% fine and coarse loam) concurrent with backscattering
coefficient measurements: 17 different volumetric water content profiles from 0 to 10 cm were
sampled including wet, intermediate, and dry conditions. Backscattering coefficients were
measured using a 4.5 GHz frequency, HH polarization and 15–20° incidence angle microwave
sensor configuration, in order to minimize the soil surface roughness effects. First, the statistical
analysis of the data (“classical calibration procedure”) exhibited satisfactory regression lines
between the backscattering coefficient and the volumetric water content calculated over arbitrary
soil depths, as described by many authors (correlation coefficients between 0.859 and 0.899).
Furthermore, the same results were obtained when water potential data were considered (log
scale). Second, taking into account the dependence between the water content profile and the
microwave penetration depth, the experimental relationship between backscattering coefficient
and volumetric water content became nonlinear and exhibited smaller residuals than the
“classical regression line.” Finally, a statistical procedure for predicting the mean and standard
deviation of volumetric water content profiles from the soil surface to the microwave penetration
depth is presented. Results showed that the proposed procedure is promising for obtaining nearsurface water content estimates used as boundary conditions for “soil/atmosphere” water
transport modeling.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V6V-489RPGC1F&_user=6763742&_coverDate=11%2F30%2F1988&_rdoc=1&_fmt=high&_orig=search&_sort=d&_doc
anchor=&view=c&_searchStrId=1356169900&_rerunOrigin=scholar.google&_acct=C000070526&_versio
n=1&_urlVersion=0&_userid=6763742&md5=719a96955beb96df34fc2043363a23f9
measurements
L. Bruckler*, H. Witono† and P. Stengel*
†
*
Department of Soil Science, Bogor Agricultural University, J1. Raya Pajajaran, Bogor,
Indonesia
INRA Station de Science du Sol, B.P. 91, Domaine Saint Paul, 84140 Montfavet, France
Abstract
Soil moisture, water potential, and bulk density measurements were performed on a 0.4
ha bare field (27.2% clay, 61.7% fine and coarse loam) concurrent with backscattering
coefficient measurements: 17 different volumetric water content profiles from 0 to 10 cm were
sampled including wet, intermediate, and dry conditions. Backscattering coefficients were
measured using a 4.5 GHz frequency, HH polarization and 15–20° incidence angle microwave
sensor configuration, in order to minimize the soil surface roughness effects. First, the statistical
analysis of the data (“classical calibration procedure”) exhibited satisfactory regression lines
between the backscattering coefficient and the volumetric water content calculated over arbitrary
soil depths, as described by many authors (correlation coefficients between 0.859 and 0.899).
Furthermore, the same results were obtained when water potential data were considered (log
scale). Second, taking into account the dependence between the water content profile and the
microwave penetration depth, the experimental relationship between backscattering coefficient
and volumetric water content became nonlinear and exhibited smaller residuals than the
“classical regression line.” Finally, a statistical procedure for predicting the mean and standard
deviation of volumetric water content profiles from the soil surface to the microwave penetration
depth is presented. Results showed that the proposed procedure is promising for obtaining nearsurface water content estimates used as boundary conditions for “soil/atmosphere” water
transport modeling.
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V6V-489RPGC1F&_user=6763742&_coverDate=11%2F30%2F1988&_rdoc=1&_fmt=high&_orig=search&_sort=d&_doc
anchor=&view=c&_searchStrId=1356169900&_rerunOrigin=scholar.google&_acct=C000070526&_versio
n=1&_urlVersion=0&_userid=6763742&md5=719a96955beb96df34fc2043363a23f9