Maximilian Weigand, Egon Zimmermann, Valentin Michels, Johan Alexander Huisman, Andreas Kemna
{"title":"Design and operation of a long-term monitoring system for spectral electrical impedance tomography (sEIT)","authors":"Maximilian Weigand, Egon Zimmermann, Valentin Michels, Johan Alexander Huisman, Andreas Kemna","doi":"10.5194/gi-11-413-2022","DOIUrl":null,"url":null,"abstract":"Spectral electrical impedance tomography (sEIT) is increasingly used to\ncharacterise the structure of subsurface systems using measurements in the megahertz to kilohertz range.\nAdditionally, hydrogeophysical and biogeophysical processes are characterised and\nmonitored using sEIT.\nThe method combines multiple, spatially distributed, spectroscopic measurements\nwith tomographic inversion algorithms to obtain images of the complex\nelectrical resistivity distribution in the subsurface at various frequencies.\nSpectral polarisation measurements provide additional information about the\nsystems under investigation and can be used to reduce ambiguities that occur\nif only the in-phase resistivity values are analysed.\nHowever, spectral impedance measurements are very sensitive\nto details of the measurement setup as well as to external noise and error\ncomponents.\nDespite promising technical progress in improving measurement quality as well\nas progress in the characterisation and understanding of static\npolarisation signatures of the subsurface, long-term (i.e. multi-month to\nmulti-year) monitoring attempts with fixed setups are still rare.\nYet, measurement targets often show inherent non-stationarity that would\nrequire monitoring for a proper system characterisation.\nWith the aim of improving operating foundations for similar endeavours, we here\nreport on the design and field deployment of a permanently installed monitoring\nsystem for sEIT data.\nThe specific aim of this monitoring installation is the characterisation of\ncrop root evolution over a full growing season, requiring multiple measurements\nper day over multiple months to capture relevant system dynamics.\nIn this contribution, we discuss the general layout and design of the\nmonitoring setup, including the data acquisition system, additional on-site\nequipment, required corrections to improve data quality for high frequencies,\ndata management and remote-processing facilities used to analyse the measured\ndata.\nThe choice and installation of electrodes, cables and measurement\nconfigurations are discussed and quality parameters are used for the\ncontinuous assessment of system functioning and data quality.\nExemplary analysis results of the first season of operation highlight the\nimportance of continuous quality control.\nIt is also found that proper cable elevation decreased capacitive leakage currents\nand in combination with the correction of inductive effects led to\nconsistent tomographic results up to 1 kHz measurement frequency.\nOverall, the successful operation of an sEIT monitoring system over multiple\nmonths with multiple daily tomographic measurements was achieved.","PeriodicalId":48742,"journal":{"name":"Geoscientific Instrumentation Methods and Data Systems","volume":null,"pages":null},"PeriodicalIF":1.8000,"publicationDate":"2022-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Geoscientific Instrumentation Methods and Data Systems","FirstCategoryId":"89","ListUrlMain":"https://doi.org/10.5194/gi-11-413-2022","RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
Spectral electrical impedance tomography (sEIT) is increasingly used to
characterise the structure of subsurface systems using measurements in the megahertz to kilohertz range.
Additionally, hydrogeophysical and biogeophysical processes are characterised and
monitored using sEIT.
The method combines multiple, spatially distributed, spectroscopic measurements
with tomographic inversion algorithms to obtain images of the complex
electrical resistivity distribution in the subsurface at various frequencies.
Spectral polarisation measurements provide additional information about the
systems under investigation and can be used to reduce ambiguities that occur
if only the in-phase resistivity values are analysed.
However, spectral impedance measurements are very sensitive
to details of the measurement setup as well as to external noise and error
components.
Despite promising technical progress in improving measurement quality as well
as progress in the characterisation and understanding of static
polarisation signatures of the subsurface, long-term (i.e. multi-month to
multi-year) monitoring attempts with fixed setups are still rare.
Yet, measurement targets often show inherent non-stationarity that would
require monitoring for a proper system characterisation.
With the aim of improving operating foundations for similar endeavours, we here
report on the design and field deployment of a permanently installed monitoring
system for sEIT data.
The specific aim of this monitoring installation is the characterisation of
crop root evolution over a full growing season, requiring multiple measurements
per day over multiple months to capture relevant system dynamics.
In this contribution, we discuss the general layout and design of the
monitoring setup, including the data acquisition system, additional on-site
equipment, required corrections to improve data quality for high frequencies,
data management and remote-processing facilities used to analyse the measured
data.
The choice and installation of electrodes, cables and measurement
configurations are discussed and quality parameters are used for the
continuous assessment of system functioning and data quality.
Exemplary analysis results of the first season of operation highlight the
importance of continuous quality control.
It is also found that proper cable elevation decreased capacitive leakage currents
and in combination with the correction of inductive effects led to
consistent tomographic results up to 1 kHz measurement frequency.
Overall, the successful operation of an sEIT monitoring system over multiple
months with multiple daily tomographic measurements was achieved.
期刊介绍:
Geoscientific Instrumentation, Methods and Data Systems (GI) is an open-access interdisciplinary electronic journal for swift publication of original articles and short communications in the area of geoscientific instruments. It covers three main areas: (i) atmospheric and geospace sciences, (ii) earth science, and (iii) ocean science. A unique feature of the journal is the emphasis on synergy between science and technology that facilitates advances in GI. These advances include but are not limited to the following:
concepts, design, and description of instrumentation and data systems;
retrieval techniques of scientific products from measurements;
calibration and data quality assessment;
uncertainty in measurements;
newly developed and planned research platforms and community instrumentation capabilities;
major national and international field campaigns and observational research programs;
new observational strategies to address societal needs in areas such as monitoring climate change and preventing natural disasters;
networking of instruments for enhancing high temporal and spatial resolution of observations.
GI has an innovative two-stage publication process involving the scientific discussion forum Geoscientific Instrumentation, Methods and Data Systems Discussions (GID), which has been designed to do the following:
foster scientific discussion;
maximize the effectiveness and transparency of scientific quality assurance;
enable rapid publication;
make scientific publications freely accessible.