Ty Paul Andrew Ferré

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[1] Soil moisture content on a horizontal scale of hectometers and at depths of decimeters can be inferred from measurements of low-energy cosmic-ray neutrons that are generated within soil, moderated mainly by hydrogen atoms, and diffused back to the atmosphere. These neutrons are sensitive to water content changes, but largely insensitive to variations in(More)
[1] We present here a simple and robust framework for quantifying the effective sensor depth of cosmic ray soil moisture neutron probes such that reliable water fluxes may be computed from a time series of cosmic ray soil moisture. In particular, we describe how the neutron signal depends on three near-surface hydrogen sources: surface water, soil moisture,(More)
We want to develop a dialogue between geophysicists and hydrologists interested in synergistically advancing process based watershed research. We identify recent advances in geophysical instrumentation, and provide a vision for the use of electrical and magnetic geophysical instrumentation in watershed scale hydrology. The focus of the paper is to identify(More)
[1] There is increasing interest in the use of multiple measurement types, including indirect (geophysical) methods, to constrain hydrologic interpretations. To date, most examples integrating geophysical measurements in hydrology have followed a three‐step, uncoupled inverse approach. This approach begins with independent geophysical inversion to infer the(More)
We hydrologists can do a better job of supporting water-resources decision-making. I will argue that we can do this by recognizing that decision makers use qualitative, multiple-narrative approaches. So, rather than providing single-model predictions with quantitative uncertainties, we should develop teams of rival models that inform decision makers about(More)
A MATLAB program was developed to invert first arrival travel time picks from zero offset profiling borehole ground penetrating radar traces to obtain the electromagnetic wave propagation velocities in soil. Zero-offset profiling refers to a mode of operation wherein the centers of the bistatic antennae being lowered to the same depth below ground for each(More)
electrode arrays allows for the interpretation of the two-dimensional distribution of electrical conductivity in the The analytic element method is used to investigate the spatial subsurface. The electrical conductivity distribution can sensitivity of different electrical resistivity tomography (ERT) arrays. By defining the sensitivity of an array to a(More)
[1] Terrestrial water storage is a basic element of the hydrological cycle and a key state variable for land surface-atmosphere interaction. However, measuring water storage in a comprehensive way for different storage compartments and beyond the point scale is a challenge. In this study, we explore a 10-year time series of total water storage changes(More)
Impulse Time Domain Transmission (ITDT) has been used to measure the complex dielectric permittivity of media such as ethanol, water and variably saturated sand. This paper applies ITDT to measurements of the complex dielectric permittivity of a vegetation canopy. The dielectric permittivity of a vegetation canopy is very close to that of air and only very(More)
We examine in-place recharge as an example of the complex, basin-scale hydrologic processes that are being represented with simplified numerical models. The rate and distribution of recharge depend on local meteorological conditions and hydrogeologic properties. The pattern of recharge is defined predominantly by the distribution of net precipitation(More)