H13K-1729
Recent Developments in Active and Passive Distributed Temperature Sensing for Soil Moisture Monitoring

Monday, 14 December 2015
Poster Hall (Moscone South)
Susan C Steele-Dunne1, Jianzhi Dong2, Olivier Hoes3, Nick Van De Giesen1, Chadi Sayde4, Tyson E. Ochsner5 and John S Selker6, (1)Delft University of Technology, Faculty of Civil Engineering and Geosciences, Delft, Netherlands, (2)Delft University of Technology, Delft, 5612, Netherlands, (3)Delft University of Technology, Delft, Netherlands, (4)Oregon State University, Corvallis, OR, United States, (5)Oklahoma State University Main Campus, Stillwater, OK, United States, (6)Oregon State University, Biological and Ecological Engineering, Corvallis, OR, United States
Abstract:
In this presentation we will review recent developments in both active and passive Distributed Temperature Sensing (DTS) for soil moisture monitoring. DTS involves using fiber-optic cables to measure temperature at sub-meter resolution along cables up to several kilometers in length. Soil thermal properties depend on soil moisture. Hence, temperature variations either in response to externally-applied heating (active) or the response to net radiation (passive) can be monitored and used to infer soil moisture.

DTS occupies a unique measurement niche, potentially providing soil moisture information at sub-meter resolution over extents on the order of km at sub-daily time steps. It complements observations from point sensors to other innovative measurement techniques like cosmic ray neutron detection methods and GPS reflectometry. DTS is being developed as a tool for the validation of soil moisture observations from remote sensing and for hydrological field investigations.

Here, we will discuss both technological and theoretical advances in active and passive DTS for soil moisture monitoring. We will present data from new installations in the Netherlands and the USA to illustrate recent developments. In particular, we will focus on the value of combining temperature observations from DTS with physical models using data assimilation. In addition to yielding improved soil moisture and temperature profile estimates, recent research has shown the potential to also derive information on the soil thermal and hydraulic properties. We will conclude by outlining the current challenges, with particular emphasis on combining active and passive DTS.