نتایج جستجو برای: soil calibration

تعداد نتایج: 235038  

2017
Mauro Holzman Raúl Rivas Facundo Carmona Raquel Niclòs

Optimization of field techniques is crucial to ensure high quality soil moisture data. The aim of the work is to present a sampling method for undisturbed soil and soil water content to calibrated soil moisture probes, in a context of the SMOS (Soil Moisture and Ocean Salinity) mission MIRAS Level 2 soil moisture product validation in Pampean Region of Argentina. The method avoids soil alterati...

2011
Ali Fares Farhat Abbas Domingos Maria Alan Mair

Single capacitance sensors are sensitive to soil property variability. The objectives of this study were to: (i) establish site-specific laboratory calibration equations of three single capacitance sensors (EC-20, EC-10, and ML2x) for tropical soils, and (ii) evaluate the accuracy and precision of these sensors. Intact soil cores and bulk samples, collected from the top 20 and 80 cm soil depths...

2008
Joel B. Sankey Rick L. Lawrence Jon M. Wraith

Agricultural producers require knowledge of soil water at plant rooting depths,while many remote sensing studies have focused on surface soil water or mechanisticmodels that are not easily parameterized. We developed site-specific empirical models topredict spring soil water content for two Montana ranches. Calibration data sample sizeswere based on the estimated variability of soil water and t...

2015
Yuxi Zhang Yuan Li Jeffrey P. Walker Valentijn R. N. Pauwels Mahshid Shahrban

Timely and reliable flood forecasting is critical for flood warning delivery and emergency response. As core components of an operational forecasting system, hydrological models are typically calibrated using streamflow measurements to minimize parameter uncertainties. The rapid development of earth observation techniques provides opportunities to obtain soil moisture information. As catchment ...

2004
Ismail Bogrekci Won Suk Lee

Abstract. The reflectance spectra of the soil samples are influenced by soil particle size. Elimination of this effect requires a calibration model to remove the effect of soil particle size. Therefore, this study aimed to investigate the effects of soil particle size on reflectance spectra of sandy soil samples and to produce a particle size calibration model for the spectra of a sandy soil sa...

2017
Heye R. Bogena Johan Alexander Huisman Bernd Schilling Ansgar Weuthen Harry Vereecken

Soil water content is a key variable for understanding and modelling ecohydrological processes. Low-cost electromagnetic sensors are increasingly being used to characterize the spatio-temporal dynamics of soil water content, despite the reduced accuracy of such sensors as compared to reference electromagnetic soil water content sensing methods such as time domain reflectometry. Here, we present...

E Maroufpoor, M Behzadi Nasab

This study carried out on the provided textures at laboratory. The provided textures were infusedinside the PVC cylinder with 30cm height and 25cm diameter. The studied textures were loamysand, sandy loam, sandy clay-loam, clay loam and clay. After 24 hours of saturation, the soil watercontent of the samples was measured by oven-dry gravimetric and TDR methods. For each texturesat any stage of ...

2007
J. P. Walker R. Panciera R. Young E. J. Kim

Reliable soil moisture measurements over large areas are much needed for both hydrologic modelling and remote sensing applications. For collecting such data, portable electronic sensors offer a practical alternative to gravimetric measurements. The conversion of the measured electrical output to soil moisture is nonetheless a non trivial task as it depends on soil type and temperature. In this ...

2007
J. P. Walker R. Panciera

Reliable soil moisture measurement over large areas is much needed for both hydrologic modelling and remote sensing applications. For collecting such data, portable electronic sensors offer a practical alternative to gravimetric measurements. The conversion of the measured electrical output to soil moisture is nonetheless a non-trivial task as it depends on soil type and temperature. In this st...

2009
M. J. Escorihuela A. Chanzy

a r t i c l e i n f o The aim of this study is to analyze the influence of the soil moisture sampling depth in the parameterization of soil emission in microwave radiometry at L-band. The analysis is based on brightness temperature, soil moisture and temperature measurements acquired over a bare soil during the SMOSREX experiment. A more detailed profile of surface soil moisture was obtained wi...

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