Concept information
Preferred term
TDR
Definition
- In the past 20 years use of the soil?s dielectric properties to determine moisture content have been met with increasing technological success through use Time Domain Reflectometry (TDR). The TDR method is based on determining the propagation time of an electromagnetic pulse traveling along a probe segment in the soil. The TDR device first measures the round-trip time for the pulse to travel to the beginning of the segment, which is indicated by the presence of a diode. Then the round-trip propagation time to the end of the segment is measured. The resulting value is used to determine the dielectric constant of the material. This value, when compared to the dielectric constant of pure water and mineral soil, will indicate the amount of water found in the medium. [Summary provided by North Dakota State University] (en)
Broader concept
- Probes (en)
URI
https://gcmd.earthdata.nasa.gov/kms/concept/cffa876f-b568-41cb-8561-9b13d68c24fe
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