DiHPS - A Distributed Heat Pulse Sensor Network for the quantification of subsurface heat and water fluxes

Lead Research Organisation: University of Birmingham
Department Name: Sch of Geography, Earth & Env Sciences


We propose the development of a novel, distributed soil moisture and temperature monitoring network that will present a step change from currently available monitoring technologies, which tend to be based on data collection at isolated points in time and space, to real-time, spatially-distributed data collection that enable effective and responsive decision making to deal with rapidly increasing demands in a changing climate.

The proposed system will be based on combining Distributed Temperature Sensor (DTS) technology with an active heat source. The so-called Active DTS (A-DTS) allows observing flow-related heating and cooling patterns along the actively heated cable. It is this Distributed Heat Pulse, A-DTS technology that we will use in the development of the proposed Sensor network - DiHPS. While broader applications in heat and water flux assessments will be possible with DiHPS, in this project we will focus on demonstrating its suitability to quantify the moisture content and thermal properties of the soil.

Description of the spatial and temporal distribution/ dynamics of these soil parameters is important for many agricultural, engineering and meteorological applications. Soil moisture, for example, is a key state variable in controlling land-atmosphere interactions and an early indicator of changes in the hydrological system, e.g. associated with daily evapotranspiration or event-based recharge cycles or with extreme events (i.e., droughts or floods). It is widely used in agriculture (e.g., irrigation management), forestry (e.g. plantation water demand estimations), meteorology (e.g. local and regional weather forecasts), water resources management (e.g. estimation of groundwater recharge) as well as a state indicator variable in drought / flood early warning systems. Soil thermal properties influence the partitioning of energy within the ground and at the ground surface, and are related to soil temperature and the movement of heat and water within the ground and their transfer across the ground surface. For these reasons, soil physicists, crop scientists and micrometeorologists study thermal properties, and they are also important in engineering applications, (e.g., determining the electric current rating of buried cables, ground heat exchanger design).

We will build on earlier work which has demonstrated the principal capacity of A-DTS to measure soil moisture under controlled conditions in a lysimeter facility. We will expand this technology from a single point application to a distributed, real time sensor network and a coiled, vertical A-DTS profiler for measuring soil moisture content and thermal properties at high spatial and temporal resolution. The network and profiler will be tested at TRL4 by installing it at our test site at the Birmingham Institute for Forestry Research (BIFoR). The results will be compared with in-situ soil moisture content and thermal property data from Frequency-Domain Reflectometry (FDR) soil moisture probes and thermal needle probe measurements, respectively. To achieve real-time, autonomous system operation, a set of heating strategies will be tested and initial threshold (trigger values) will be defined. These will define at what change in soil temperature, as observed by continuous temperature observation in DTS passive mode, initiation/cessation of the DTS active mode will be triggered.

A key component of DiHPS is the real-time control for triggering the change from active to passive observation mode. This will require the development of a set of algorithms, based on inverse modelling and asymptotic approaches, which can process the raw DTS data in real-time to provide the required outputs. No existing DTS-application attempts to provide temperature or soil moisture data temperature in such detail and in real-time. If successful, we anticipate a step change in the way DTS is employed, e.g. in early warning systems or for providing detailed process understanding.

Planned Impact

Technical constraints to measure and monitor soil moisture and subsurface heat and water fluxes at adequate spatial and temporal scales result in critical limitations of the predictive capacity of hydrological and atmospheric models and hence hinder the reliable assessment of available water resources.

This project will develop Active Distributed Temperature Sensor network technologies for unprecedented high-frequency/resolution monitoring of soil moisture, subsurface temperature and thermal properties in real time. This development will improve the understanding of non-linear responses of soil moisture and sub-surface heat and water fluxes to climate and land use changes. The project will therefore benefit a wide range of academic researchers (hydrologists, ecologists, and atmospheric scientist, engineers, regulators, practitioners and policy makers.

The potential for monitoring soil moisture, water and heat fluxes in real time using the DiHPS system will lead to an improved quantification of water resources and support a move towards adaptive resource management in agriculture and forestry. Climate/management-induced shifts in the water balance towards drought or flood conditions or excessive drying/wetting of the soils will be easier detectable (and at an earlier point in time) with the improved methodology than currently feasible, and therefore can be dealt with at an earlier stage. Furthermore, DiHPS' capability to capture fine-scale variability in soil moisture over relatively large areas will also support the validation and enhance the usefulness of large-scale remote sensing products, such as from ESA's SMOS, Sentinel-1 or ASCAT sensors or from SMAP (NASA). Hence, DiHPS has the potential to directly impact national and European policy on the use of the natural resources, and directly links to NERC programmes such as Living with Environmental Change.

We developed an Impact Strategy (see Pathways to Impact) that is based on engagement with main stakeholders (see Letters of Support) and potential users of our technology and the process understanding derived by its application (Forestry Research, European Space Agency, CEH-COSMOS, BIFoR - Birmingham Institute for Forestry Research, Norburry Park Estate and our project partners SILIXA Ltd.) in the fields of forestry and agriculture, environmental planning and regulation, hydrological modelling and forecasting, water supply, thermal (ground) engineering, as well as provision of distributed fibre-optic sensing solutions.

To best facilitate the uptake of the projects research the project established an Advisory Board (meeting in month 1, 6 and 12 with month 4 + 8 progress reports in between) consisting of practitioners and industry partners has been formed. Board members have already contributed actively to the design of the project and will play a key role in the facilitation of the projects outreach and impact strategies. The research will be disseminated to the scientific community by peer-review paper publications and attendance at relevant scientific conferences. To create immediate impact beyond the scientific community, project outcomes, summary reports and newsletters as well as data and tools will be communicated through the interactive project website via links to social media and wiki-functionality. Other communication pathways will include linkages to stakeholder and NERC web portals, public media appearances and the regular (at least 3-monthly) publication of general-interest articles, podcasts and vodcasts online and distributed to all stakeholders. A practitioners workshop will be organised with the support of the SILIXA Ltd. project partners to provide training on the real-time monitoring of soil moisture with A-DTS to demonstrate the capacity of A-DTS technology to relevant stakeholders and users of DiHPS. (For out detailed impact strategy please see the Pathways to Impact document).


10 25 50
publication icon
Abesser C (2020) A distributed heat pulse sensor network for thermo-hydraulic monitoring of the soil subsurface in Quarterly Journal of Engineering Geology and Hydrogeology

publication icon
Blöschl G (2019) Twenty-three unsolved problems in hydrology (UPH) - a community perspective in Hydrological Sciences Journal

Description Active FO-DTS provides a robust tool for monitoring soil moisture at unprecedented spatial resolution. Measurement accuracies are in the. range of state of the art TDR technologies.
Exploitation Route The successful pioneering of the A-DTS technology for soil moisture monitoring opens opportunities for use in soils science and will be taken forward in a highlight topic application.
Sectors Agriculture, Food and Drink,Energy,Environment,Transport

Title A-DTS for soil moisture monitoring 
Description worldwide first continues soil moisture monitoring by A-DTS sensor network 
Type Of Material Improvements to research infrastructure 
Provided To Others? No  
Impact in progress 
Title BIFoR FACE environmental monitoring data 
Type Of Material Database/Collection of data 
Year Produced 2020 
Provided To Others? Yes  
URL http://edata.bham.ac.uk/564/
Description Collaboration with JABBS Foundation 
Organisation JABBS Foundation
Country United Kingdom 
Sector Charity/Non Profit 
PI Contribution FO-DTS investigation of soil water fluxes in irrigated forest plantation
Collaborator Contribution Funding of PhD studentship
Impact No outputs yet
Start Year 2019
Description FO-DTS for subsurface flow monitoring on waste sites 
Organisation National Nuclear Laboratory
Country United Kingdom 
Sector Public 
PI Contribution We have started collaborating on developing FO-DTS solutions for subsurface flow monitoring on waste sites
Collaborator Contribution NNL provides infrastructural support and advice on the installation of sub-surface FO-DTS
Impact Application to Game Changer programme (multidisciplinary)
Start Year 2020
Title New FO-DTS calibration technology 
Description The proposed two-way single-ended averaging of FO-DTS surveys had significant advantages compared to single-ended or double-ended surveys, with a higher accuracy in signal detection, in particular for small-scale temperature variations. Since FO-DTS surveys in two-way single-ended averaging mode were better suited for detecting the full complexity of spatial temperature patterns for the investigated aquifer-river interface, we recommend its wider application in similarly complex systems with small-scale thermal patterns. 
Type Of Technology New/Improved Technique/Technology 
Year Produced 2017 
Impact not yet 
Description Contribution to Birmingham Institute of Forest Research (BIFoR) Fall 2017 Newsletter 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Contribution to the BIFoR Fall 2017 Newsletter for general public
Year(s) Of Engagement Activity 2017
URL https://www.birmingham.ac.uk/Documents/college-les/gees/bifor/BIFoR-autumn-2017-newsletter.pdf
Description Poster for BIFoR National Annual meeting 2016-2017 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Introduction to a broad audience of the measurements, activities, techniques in use at BIFoR site
Year(s) Of Engagement Activity 2016,2017
Description Presentation at AGU Fall meeting in Washington: Thermal sensitivity of CO2 and CH4 emissions varies with streambed sediment properties 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Organisation of: H11H: Advances in Integrating Novel Monitoring Data with Distributed Hydrologic Models
Year(s) Of Engagement Activity 2018
Description Presentation to Annual Workshop of Midlands Soil Discussion Group 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Professional Practitioners
Results and Impact Introduction of cutting edge but affordable soil monitoring technology to soil experts and undergraduate students
Year(s) Of Engagement Activity 2017
URL http://www.soils.org.uk/event/1196