Accurate soil moisture content measurements are vital to precision irrigation management. Remote sensing using the microwave spectrum (such as GPS signals) has been used for measuring large area soil moisture contents. In our previous work, we estimated surface soil moisture contents for bare soil using a GPS Delay Mapping Receiver (DMR) developed by NASA. However, the effect of vegetation was ...

The Tau-Omega model of microwave emission from soil and vegetation layers is widely used to estimate soil moisture content from passive microwave observations. Its application to prospective satellite-based observations aggregating several thousand square kilometres requires understanding of the effects of scene heterogeneity. The effects of heterogeneity in soil surface roughness, soil moistur...

This paper examines the effects of soil moisture initialization in a coupled air quality–meteorological model on temperature profiles, wind speeds, and pollutant concentrations. Three simulations, each with different initial soil moisture fields, were run. In the baseline simulation, predicted temperatures, wind speeds, and gas/aerosol pollutant concentrations accurately matched observations. I...

Soil moisture retrieval from SAR images using semi-empirical or physically-based backscatter models requires surface roughness parameters, generally obtained by means of in situ measurements. However, measured roughness parameters often result in inaccurate soil moisture contents. Furthermore, when these retrieved soil moisture contents need to be used in data assimilation schemes, it is import...

Soil is a mixture of four components: air, free water, bound water and soil particles. The microwave dielectric constant of soil is strongly dependent on the soil moisture content. The dielectric constant is a measure of the response of a material to an applied electric field, such as an electromagnetic wave. It has a real and an imaginary component. Soil particles’ dielectric constant depends ...

Comparisons to ground-based surface soil moisture estimates are necessary to evaluate the capability of remote sensors to determine soil moisture and its spatiotemporal variability. Soil moisture can be especially variable in regions of complex terrain which exhibit large variations in vegetation, soil properties and hydrologic conditions. The objective of this study is to evaluate the spatiote...

Adoption of new management techniques that improve soil water storage and soil N plant availability yet limit N leaching may help improve environmental quality. A benchtop study was conducted to determine the influence of a single urea fertilizer rate (224 kg N ha) applied with band or fully mixed zeolite (clinoptilolite) application rates (up to 90 Mg ha) on NH4-N and NO3-N concentrations in a...

Root zone soil moisture is a key variable in many land surface hydrology models. Often, however, there is a mismatch in the spatial scales at which models simulate soil moisture and at which soil moisture is observed. This complicates model validation. The increased availability of detailed datasets on space-time variability of root-zone soil moisture allows for a posteriori analysis of the unc...

Accumulation of beef cattle manure on feedlot pen surfaces generates large amounts of dissolved solutes that can be mobilized by water fluxes, affecting surface and groundwater quality. Our objective was to examine the long-term impacts of a beef cattle feeding operation on water fluxes and manure leaching in feedlot pens located on sandy loam soils of the subhumid Sandy Pampa region in Argenti...

Tropical forests play an important role in regulating the global climate and the carbon cycle. With the changing temperature and moisture along the elevation gradient, the Luquillo Experimental Forest in Northeastern Puerto Rico provides a natural approach to understand tropical forest ecosystems under climate change. In this study, we conducted a soil translocation experiment along an elevatio...