Monitoring the unfrozen water content of soil and snow using time domain reflectometry

Abstract

Topp and Davis [this issue] are disturbed because we introduced the concept of capacitance into our presentation about time domain refiectometry (TDR). We [Stein and Kane, 1983]. preceded our discussion on TDR with some introductory paragraphs about capacitance because we felt that capacitance is a more widely known concept than dielectric constant and because we felt that there are some analogies between the two subjects that lead to a better understanding of the concept of measuring dielectric properties.In response to the comment of Topp and Davis about the geometry of capacitors and probes for TDR, we did not intend to imply in our introductory section that they must have the same configuration. In the first case, we are talking strictly about capacitors. In the second instance, we discuss measuring dielectric properties.There has been concern expressed by Topp and Davis and others about the design of what we call our 300-ohm TV wire system. As is stated in the paper, it was only used for 1 year because we noted many of the limitations of this system as expressed by others. However, at the time we received funds for this instrumentation, we had very little time to experiment with various configurations in the laboratory if we were going to collect field data during that winter and following snowmelt period. Since we wanted to specifically monitor snowmelt infiltration into seasonally frozen soils, we went ahead and installed the probes using the 300-ohm TV wire. However, we continued to examine other designs in the laboratory and soon developed the present design that we have used extensively in all types of soils. The lengthy exploration of Topp and Davis into limitations of our first system is an excellent, detailed description of why we abandoned this sytem after the first field year. REFERENCES Stein, J., and D. L. Kane, Monitoring the unfrozen water content of soil and snow using time domain refiectrometry, Water Resour.

High dielectric insulation coating for time domain reflectometry soil moisture sensor

“…Superimposing these two signals allows us to determine the separation point, which corresponds to the aforementioned starting point. As demonstrated by several researchers [e.g., Stein and Kane, 1983;Ledieu et al, 1986;Rajkai and Rydén, 1992;Kelly et al, 1995], a two-rod probe can be used to measure soil dielectric constants without a balun. In this experimental work, a balun was not used for the probe.…”

Energy and Water Cycles in a High-Latitude, North-Flowing River System

“…Infiltration of snowmelt into frozen ground involves simultaneous coupled heat and mass transfers with phase changes (Stein and Kane 1983;Zhao et al 1997). The processes are complex, and a multilayered soil model with small grid spacing best describes the resulting soil temperature gradients ).…”

Water content as a function of apparent dielectric permittivity in a Fibric Limnic Humisol

“…On one hand, only a few u v -Ka relationships have been published for organic porous media (Stein and Kane 1983;Pe´pin et al 1992;Roth et al 1992;Paquet et al 1993;Schaap et al 1996). Their relationships have similar general form, but have different regression coefficients (Table 1).…”