Estimation model between soil moisture content and the near infrared reflectance was established by the linear regression method and the models between soil total nitrogen content and the near infrared reflectance were also established by the BP neural network method and Support Vector Machine (SVM) method. Forty-eight soil samples were collected from China Agricultural University Experimental ...

This study compares ERS scatterometer top soil moisture observations with simulations of a dual layer conceptual hydrologic model. The comparison is performed for 148 Austrian catchments in the period 1991–2000. On average, about 5 to 7 scatterometer images per month with a mean spatial coverage of about 37% are available. The results indicate that the agreement between the two top soil moistur...

[1] To overcome the difficulties in determining the optimal parameters needed for a radiative transfer model (RTM), which acts as the observational operator in a land data assimilation system, we have designed a dual-pass assimilation (DP-En4DVar) framework to optimize the model state (volumetric soil moisture content) and model parameters simultaneously using the gridded Advanced Microwave Sca...

Time Domain Reflectometry (TDR) is a well-established technique for the development of microwave sensors devoted to the dielectric characterization of materials. In particular the TDR has become the standard method for measuring soil water content. Although the response of the TDR signal is strictly related to the medium moisture content, it is also affected by several others factors related to...

This research combines Particle Image Velocimetry (PIV) and transparent soil to investigate the dynamic rigid block and soil interaction. In order to get a low viscosity pore fluid for the transparent soil, 12 different types of chemical solvents were tested and the two best-matching pore fluids were identified. Transparent soil was adopted in the research as a substitute for natural sand. To e...

An artificial neural network (ANN) calibration model was developed to determine aluminum in the presence of iron in soil extracts, using xylenol orange as chromogenic reagent. The spectral data of synthetic mixtures of Al(3+) and Fe(3+) as well as of the soil extracts, were recorded in the range between 410 and 580 nm. Method validation was carried out using 18 soil extracts. The results gave g...

Since 1990s, time domain reflectometry (TDR) has been applied to estimate the stem water content of living trees. Here, new calibration equations relating the apparent dielectric constant (Ka) to the volumetric water content (θ) were developed for two Mediterranean oak species. Our calibration equations differ from those previously calculated for other species, suggesting that stem water conten...

In the last few years, we have gathered experience in measurement of 222 Rn in air, water and soil-gas by absorption in polycarbonates. The method employs the remarkable absorption ability to noble gases of some polycarbonates, like Makrolon ® (the basic constructive material of CDs/DVDs). This report summarizes the key results of research and practical applications of this method. Calibration ...

This paper presents a very accurate sensor for the measurement of the moisture of undisturbed soil samples. The sensor relies on accurate estimation of the permittivity which is performed independently of the soil type, and a subsequent calibration. The sensor is designed as an upgrade of the conventional soil sampling equipment used in agriculture--the Kopecky cylinder. The detailed descriptio...