Distributed Temperature Sensing (DTS) measures moisture

DTS for moisture estimationPassive distributed temperature sensing (DTS) helps to improve the measurement of moisture content and temperature increase. The DTS technology has been already tested in China to prove the opportunities provided by this technique. Therefore, distributed temperature sensors are very promising for agriculture.

Several land conditions include bare soil, plastic mulch, plastic mulch covered with potatoes, and plastic much covered with maize. Land moisture plays a crucial role in influencing grain yield. Nevertheless, distributed temperature sensing is not suitable for the last type of land.

The thing is that several techniques allow for determining soil moisture content. Distributed sensing systems include point, ground, and regional types. Herewith, point fiber optic sensors consist of “oven-drying, neutron scattering, electrical impedance, time-domain reflectometry (TDR), frequency domain reflectometry (FDR), tensiometer, and thermal probe techniques.”

Conventional fiber sensors offer benefits of high precision and reliability but most of them are limited to a specific area. This is the main reason why it is difficult to determine accurately the overall ground moisture condition, especially in places where soil moisture distribution is discontinuous.

Thus, scientists have suggested applying distributed temperature sensing (DTS). DTS technology allows for estimating agricultural soil moisture, herewith, the distance of measurement can achieve several tens of kilometers. The operating principle of distributed temperature sensors is based on the heating of optical cables. When the temperature increases, the soil moisture can be estimated.

The DTS technology is not new and it quickly found the application in moisture measurement. According to this technique, it is possible to measure in situ soil moisture by employing analytical or semi-empirical models. Nevertheless, firstly it is necessary to calculate the thermal conductivity of the soil.

Compared to traditional techniques that have limitations, distributed temperature sensing allows for overcoming them. DTS estimates the temperature response of soil, therefore, measures soil moisture based on the data obtained by fiber optic sensors. Nonetheless, the proposed technique has several disadvantages.

Various weather conditions can influence the heat transfer way in the soil and the data obtained by distributed temperature sensors will be inaccurate. Additionally, boundary conditions and even time change periods also influence the precision. Finally, the standard algorithm is very difficult for application in practice.

Optromix is a DTS system manufacturer that provides top of the line distributed temperature sensing systems suitable for monitoring commerce networks. If you have any questions or would like to buy a DTS system, please contact us at info@optromix.com

Total information about fiber optic temperature sensor

FBG temperature sensorsToday all modern industries include highly complex and sensitive operations that require permanent operational conditions that are possible to provide due to the use of advanced technologies for temperature measurement. One of the potential solutions is the use of fiber optic temperature sensors.


There are several ways of temperature measurement: classic mercury glass thermometer, infrared pyrometer, electronic thermometer. However, the most effective method is fiber temperature sensing because it provides accurate measurement compared to the mentioned techniques and has numerous fields of application such as high voltage machines, nuclear power plants, chemical power plants, etc.

The types of fiber temperature sensors include interferometric and non-interferometric sensors. The traditional non-interferometric sensor has multi-mode optical fiber construction and materials that are sensitive to temperature. Also, they are able to register changes, for example, absorption, transmission, and reflection parameters due to temperature variation.

The simple interferometric fiber optic temperature sensors are more flexible and provide the sensitivity of a higher level. The fields of the use include temperature, pressure, rotation, strain, etc. The principle of the operation is the comparison of the beam phase through sensing fiber with the reference beam.

The advantages of optical temperature sensors:

  • Immunity to electromagnetic and stray radiation;
  • Possibility of the use in hard electrical conditions;
  • Greater accuracy and faster response time;
  • Lightweight and compact size;
  • Low cost;
  • Wide temperature measurement range.

Nevertheless, fiber optic temperature sensors are not ideal and have some disadvantages such as different temperature ranges of operation and measurement accuracy for different types of sensors, the difficulties of development expensive price for some optical sensors.

Optromix is a fast-growing vendor of fiber Bragg grating (FBG) products line such as fiber Bragg grating sensors, FBG interrogators and multiplexers, Distributed Acoustic Sensing (DAS) systems, Distributed Temperature Sensing (DTS)systems. The company creates and supplies a broad variety of fiber optic solutions for monitoring worldwide. If you are interested in temperature measurement systems and want to learn more, please contact us at info@optromix.com