DART TDR apparent permitivity readings

Apparent Permittivity (APT) data were extracted from the waveform collected by the Time Domain Reflectometry probes installed at each of the DART sites, both inside and outside of archaeological features. Measurements were taken every 60 minutes between May 2011 and June 2013. The 'as-design' was to install the probes in vertical arrays within the archaeological sequence (AS) and multiple vertical arrays in the surrounding soil matrix (SSM) to detect lateral variations. The 'as-built' deviated to the 'as-design' due to difficulties in installation in the different sediments. The location of each probe can be found on the section drawings in the excavation collection. A larger numbers of probes was used in the heavy clay soils as opposed to the free draining soils. The data were logged locally and collected, downloaded and processed every month. APT is calculated from TDR waveforms, which are the reflections over time of a pulse sent out from the TDR probe and collected over time. APT is mainly dependent on soil type and its water content. It is postulated that the multi-temporal APT measurements when analysed with the geotechnical, weather and temperature data will help determine why archaeological responses, detected by geophysical surveys, vary over the same position and associated issues about vegetation mark formation.

Data and Resources

Additional Info

Field Value
Author Dan Boddice
Maintainer Anthony Beck
instrument Campbell Scientific TDR100, CS645 probes and CR1000 datalogger
instrument.calibrationDetails See enclosed calibration document
instrument.headerMetadata OR RAW:'File Format', 'Station', 'Logger', 'Serial No', 'OS version', 'DLDfile', 'DLDsig', 'Tablename'. Details on these are provided in Campbell scientific CR1000 manual. each line of data is preceded by a timestamp followed by 16 waveforms preceded by header. waveform headers are described further in the TDR100 manual multiplexor code where the first two numbers refer to the channel of the first and second level of multiplexor respectively, the third number is the third level (not used and set to zero) and the forth number is the number of consecutive probes to read (set to 1) waveform averaging: the number of reflections averaged by the TDR100 (set to 50) Propagation velocity: set to 1 to use apparent lengths number of waveform points set to maximum value of 2048 apparent cable length which determines the start of the data collection time window window length which specifies the length of the data collection time window probe length (not used and left as default values due to manual processing) probe offset (not used and left as default values due to manual processing) multiplier (used for scaling waveforms-left as 1) offset (used for scaling waveforms (left as 0) THE PROCESSED RESULTS header consists of a timestamp made up of 5 columns year: the year of reading, month: the month of reading, hour: the hour of the reading, minute: the minute of the reading and second: the second of the reading. These are followed by unique probe numbers which can be related to the section drawings and TDR probe mappings file. FOR PROCESSED: 'Year', 'Month', 'Day', 'Hour', 'Minute', 'Second','Probe Numbers (1 to 16 for each station)'
instrument.measurementDomainAndUnits FOR RAW:reflection coefficient (relative voltage) as function of apparent length (time); Note, this is the same as for BEC, but it uses a different time window FOR PROCESSED: apparent relative permittivity (dimensionless as it is relative to the permittivity in free space) in SI units
instrumentID DDCF: TDR: 2530 and 2553, dataloggers: E3838 and E2278; DDPF: TDR:2551, dataloggers: E2279 HHQF: TDR: 2529 and 2532, dataloggers: E1834 and E1840 HHCC: TDR: 2531, dataloggers: E1835
resource.abstract Apparent Permittivity (APT) data were extracted from the waveform collected by the Time Domain Reflectometry probes installed at each of the DART sites, both inside and outside of archaeological features. Measurements were taken every 60 minutes between May 2011 and June 2013. The 'as-design' was to install the probes in vertical arrays within the archaeological sequence (AS) and multiple vertical arrays in the surrounding soil matrix (SSM) to detect lateral variations. The 'as-built' deviated to the 'as-design' due to difficulties in installation in the different sediments. The location of each probe can be found on the section drawings in the excavation collection. A larger numbers of probes was used in the heavy clay soils as opposed to the free draining soils. The data were logged locally and collected, downloaded and processed every month. APT is calculated from TDR waveforms, which are the reflections over time of a pulse sent out from the TDR probe and collected over time. APT is mainly dependent on soil type and its water content. It is postulated that the multi-temporal APT measurements when analysed with the geotechnical, weather and temperature data will help determine why archaeological responses, detected by geophysical surveys, vary over the same position and associated issues about vegetation mark formation.
resource.accessConstraints None
resource.bibliographicCitation @data{dart_monitoring_apparent_permitivity_cstdr100, doi = {not allocated}, url = {http://dartportal.leeds.ac.uk/dataset/dart_monitoring_apparent_permitivity_cstdr100}, author = {Dan Boddice}, publisher = {The DART project, School of Computing, University of Leeds}, title = {DART TDR apparent permitivity readings}, year = {2013}, note = {DART is a Science and Heritage project funded by AHRC and EPSRC. Further DART data and details can be found at http://dartportal.leeds.ac.uk}}
resource.completeness Complete with some gaps due to datalogging issues
resource.consistency Consistent data structure, attribution and relationships.
resource.creation.endDateTime 2013
resource.creation.startDateTime 2011
resource.creation.status Complete
resource.creator.email dxb043@bham.ac.uk
resource.creator.name Dan Boddice
resource.creator.orcID http://orcid.org/0000-0002-3738-2327
resource.custodian.email a.r.beck@leeds.ac.uk
resource.custodian.name Anthony Beck
resource.custodian.orcID http://orcid.org/0000-0002-2991-811X
resource.description Apparent Permittivity (APT) data were extracted from the waveform collected by the Time Domain Reflectometry probes installed at each of the DART sites, both inside and outside of archaeological features. Measurements were taken every 60 minutes between May 2011 and June 2013. The 'as-design' was to install the probes in vertical arrays within the archaeological sequence (AS) and multiple vertical arrays in the surrounding soil matrix (SSM) to detect lateral variations. The 'as-built' deviated to the 'as-design' due to difficulties in installation in the different sediments. The location of each probe can be found on the section drawings in the excavation collection. The exact locations for the probes are as follows: DDCF: DDPF: HHQF: HHCC: A larger numbers of probes was used in the heavy clay soils as opposed to the free draining soils. This required the use of two multiplexors which meant that two data files were created for each site (given the suffix A (where all the probes were installed in the archaeology) and N (where all the probes were installed in the 'natural'). The probes in the well draining soils were given the suffix B to refer to installation in 'Both' archaeology and 'natural'. The data were logged locally and collected, downloaded and processed every month. The aim is to provide a better understanding of when contrast between archaeological features and the surrounding soil matrix occurs and what causes this contrast in order to optimise geophysical surveys. The TDR data take the form of voltage as a function of time and represent a waveform, which can be converted into APT. Once the APT is calculated, these can be converted into soil moisture content using a number of different equations (a summary of these equations is contained within the collection). Some of the equations require specific technical information on the soils (some of which is collected in the geotechnical analysis stored in the laboratory collection). Research has shown that depending which equation is used, the variation can be up to 50percent. SPECIFIC INFORMATION ON TDR PROBES AND SETTINGS: Window apparent start length: varies (see calibration file). Window apparent length: 1.2m. Averaging: 50. Propagation Velocity: 1.0. No of points per waveform: 2048. Calibration using the methods of Heimovaara, T.J. (1993). Design of triple-wire time-domain reflectometry probes in practice and theory. Soil Science Society of America Journal, 57(6),1410-1417. and Robinson D.A., Jones S.B., Wraith J.M., Or D., and. Friedman S.P (2003) A Review of Advances in Dielectric and Electrical Conductivity Measurement in Soils Using Time Domain Reflectometry, Published in Vadose Zone Journal 2:444 475 using waveforms in air and water (10 of each) to derive probe apparent length and offset. The TDR100 Time-Domain Reflectometer is the core of the Campbell Scientific time-domain reflectometry system. This system is used to accurately determine soil volumetric water content, soil bulk electrical conductivity, rock mass deformation, or user-specific time-domain measurement. Up to 16 TDR100s can be controlled using a single Campbell Scientific datalogger. PC-TDR software is used with our TDR100-based systems during system setup and troubleshooting. It is included with the TDR100. The TDR100 (1) generates a short rise time electromagnetic pulse that is applied to a coaxial system that includes a TDR probe for soil water measurements and (2) samples and digitizes the resulting reflection waveform for analysis or storage. The elapsed travel time and pulse reflection amplitude contain information used by the on-board processor to quickly and accurately determine soil volumetric water content, soil bulk electrical conductivity, rock mass deformation or user-specific, time-domain measurement. Up to 16 TDR100s can be controlled using a single Campbell Scientific datalogger. A 250-point waveform is collected and analyzed in approximately two seconds. Each waveform can have up to 2,048 data points for monitoring long cable lengths used in rock mass deformation or slope stability. Averaging up to 128 readings makes accurate measurements possible in noisy environments. . TDR100 Specifications: Pulse generator output: 250 mV into 50 ohms. Output impedance: 50 ohms +/-1percent. Time response of combined pulse generator and sampling circuit: less than 300 picoseconds. Pulse generator aberrations: Within first 10 nanoseconds: +/-5percent After 10 nanoseconds: +/-0.5percent. Pulse length: 14 microseconds. Timing resolution: 12.2 picoseconds. Waveform sampling: 20 to 2048 waveform values over chosen length. Distance range: -2-2100m(0-7ms). Resolution: 1.8mm (6.1ps). Waveform averaging: 1 to 128. Electrostatic discharge protection: Internal clamping. Current drain: During measurement: 270 mA, Sleep mode: 20 mA, Standby mode: 2 mA. Power supply: Unregulated 12 V(9.6 V to 16 V), 300 mA maximum. Operating Temperature: -40 degree to +55 degree C. Collected with CR1000 datalogger. CR1000 Specifications. Maximum Scan Rate: 100 Hz. Analog Inputs: 16 single-ended or 8 differential individually configured. Pulse Counters: 2. Switched Excitation Channels: 3 voltage. Digital Ports: 8 I/Os or 4 RS-232 COM. Communications/Data Storage Ports: 1 CS I/O, 1 RS-232, 1 parallel peripheral. Switched 12 Volt: 1. Input Voltage Range: +/-5 Vdc. Analog Voltage Accuracy: +/-(0.06percent of reading + offset), 0 degree to 40 degree C. Analog Resolution: 0.33 microV. A/D Bits: 13. Temperature Range: Standard: -25 degree to +50 degree C Extended: -55 degree to +85 degree C. Memory: 2 MB Flash (operating system), 4 MB (CPU usage, program storage, and data storage). Power Requirements: 9.6 to 16 Vdc. Current Drain: 0.7 mA typical; 0.9 mA max. (sleep mode) 1 to 16 mA typical (w/o RS-232 communication) 17 to 28 mA typical (w/RS-232 communication). Dimensions: 23.9 x 10.2 x 6.1 cm (9.4" x 4.0" x 2.4"). Dimensions with CFM100 or NL115 attached: 25.2 x 10.2 x 7.1 cm (9.9" x 4.0" x 2.8"). Weight: 1.0 kg (2.1 lb). Protocols Supported: PakBus, Modbus, DNP3, FTP, HTTP, XML, POP3, SMTP, Telnet, NTCIP, NTP, SDI-12, SDM. CE Compliance Standards to which Conformity is Declared: IEC61326:2002. Warranty: 3 years. The CFM100 stores the datalogger's data on a removable CompactFlash (CF) card. The CFM100/CF card combination can be used to expand the datalogger's memory, transport data/programs from the field site(s) to the office, and upload power up functions. The module connects to the 40-pin peripheral port on a CR1000 or CR3000 datalogger. Technical Description: The CFM100 includes a card slot that can fit one Type I or Type II CF card. Only industrial-grade CF cards should be used with our products. Although consumer-grade cards cost less than industrial-grade cards, the consumer-grade cards are more susceptible to failure resulting in both the loss of the card and its stored data. Industrial-grade cards also function over wider temperature ranges and have longer life spans than consumer-grade cards. Data stored on the card can be retrieved either by removing the card and carrying it to a computer or through a communications link with the datalogger. The computer can read the CF card either with the computer's PCMCIA slot and the CF1 adapter or the computer's USB port and the 17752 Reader/Writer. CFM100 Specifications: Typical Access Speed: 200 to 400 kbits s-1. Memory Configuration: User selectable; ring (default) or fill-and-stop. Power Requirements: 12 V supplied through the datalogger's peripheral port. CF Card Requirements: Industrial-grade; storage capacity of 2 GB or less. Dimensions: 10.0 x 8.3 x 6.5 cm (4.0" x 3.3" x 2.6"). Dimensions of CR1000 with CFM100 attached: 25.2 x 10.2 x 7.1 cm (9.9" x 4.0" x 2.8"). Weight: 133 g (4.7 oz). Typical current drain: RS-232 Port Active Writing to Card: 30 mA Reading Card: 20 mA RS-232 Port Not Active Writing to Card: 20 mA Reading Card: 15 mA. Low Power Standby: 700 to 800 microA.
resource.distribution.technique Download only
resource.edition 1
resource.fileFormat .txt, .zip
resource.funder Science and Heritage Programme, Arts and Humanities Research Council, Engineering and Physical Sciences Research Council
resource.instructionalMethod None - this is a collection
resource.keywords Soil, Conductivity, Apparent Permitivity, Moisture, Water, Soil Moisture, Probe, Monitoring
resource.language eng
resource.license odc-by
resource.license.typeURL http://opendatacommons.org/licenses/by/
resource.lineage None: this is raw data
resource.localURI http://dartportal.leeds.ac.uk/storage/f/dart_monitoring_apparent_permitivity_cstdr100
resource.metadata.creator.email dxb043@bham.ac.uk
resource.metadata.creator.name Dan Boddice
resource.metadata.creator.orcID http://orcid.org/0000-0002-3738-2327
resource.metadata.language eng
resource.methodsAndStandards Station design and calibration based on Curioni, G., Chapman, D.N., Metje, N., Foo, K.Y., Cross, J.D. (2012) Construction and Calibration of a Field TDR Monitoring Station. Near Surface Geophysics, 10: (3): 249-261. Design modified by Boddice.
resource.processingStage Complete
resource.processingSteps FOR RAW:Conversion from binary format using CardConvert producing a sequence of discrete points representing the TDR waveform (2048 points, which is the maximum possible number of points for the TDR) FOR PROCESSED: Plot the waveform (but this can also be done numerically); Find the first derivative of the waveform using the convolution function in Matlab and apply a low pass filter to reduce noise; Use the one dimensional mean-shift function in Matlab to find the maxima and minima (peaks) in the first derivative locate these in the waveform and use 10 points either side to find the gradients of the lines; Find the local minima in the first 500 points and the last 1500 points; The start point is where the first gradient meets the first minimum and the end point is where the second one meets the second minimum to provide two inflection points; Apply a callibration equation based on Robinson D.A., Jones S.B., Wraith J.M., Or D., and. Friedman S.P (2003) A Review of Advances in Dielectric and Electrical Conductivity Measurement in Soils Using Time Domain Reflectometry, Published in Vadose Zone Journal 2:444 475 to provide apparent permittivity with the start point corrected by the probe offset. all this is done by using a Matlab script. Also see Curioni, G., Chapman, D.N., Metje, N., Foo, K.Y., Cross, J.D. (2012) Construction and Calibration of a Field TDR Monitoring Station. Near Surface Geophysics, 10: (3): 249-261 for step-by-step details on TDR callibration for APT and BEC.
resource.publisher School of Computing, University of Leeds
resource.purpose multi-temporal heritage detection
resource.relatedResources DartProjectOverview
resource.repositoryName http://dartportal.leeds.ac.uk/
resource.reuseConstraints No conditions apply for reuse (remix it, publish it, share it, commercialise it, sell it etc.) except attribution (see resource.bibliographicCitation)
resource.reusePotential archaeology, environment, heritage, soil science, farming, ecology, geography, earth science
resource.samplingStrategy Probes were installed in a known archaeological and natural profile. Data are recorded every 60 minutes.
resource.topic geoscientificInformation, environment, heritage, farming, climatology/Meteorology/Atmosphere, imageryBaseMapsEarthCover, society, structure
resource.type Dataset collection
resource.type.specific Text
resource.updateFrequency not planned
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spatial-text United Kingdom
spatial.boundingBox.OSGB36.east 519741
spatial.boundingBox.OSGB36.north 266160
spatial.boundingBox.OSGB36.referenceSystem OSGB36
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spatial.boundingBox.WGS84.eastLongitude -0.246205
spatial.boundingBox.WGS84.northLatitude 52.280552
spatial.boundingBox.WGS84.referenceSystem WGS84
spatial.boundingBox.WGS84.southLatitude 51.703178
spatial.boundingBox.WGS84.westLongitude -1.907587
spatial.defaultReferenceSystem OSGB36
spatial.driftGeology DDCF: http://www.bgs.ac.uk/lexicon/lexicon.cfm?pub=TILMP, DDPF: http://www.bgs.ac.uk/Lexicon/lexicon.cfm?pub=T1T2, HHCC: Clay: no superficial drift geology, HHQF: no superficial drift geology
spatial.landuse Permanent pasture: DDPF, Arable: DDCF, HHCF, HHQF
spatial.ordnanceSurveyPlaceName Harnhill (http://data.ordnancesurvey.co.uk/id/50kGazetteer/109734) and Diddington (http://data.ordnancesurvey.co.uk/id/50kGazetteer/72767)
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spatial.solidGeology DDCF and DDPF: http://www.bgs.ac.uk/lexicon/lexicon.cfm?pub=OXC, HHCC: http://www.bgs.ac.uk/lexicon/lexicon.cfm?pub=CB, HHQF: http://www.bgs.ac.uk/lexicon/lexicon.cfm?pub=SI
temporal.rangeDescribedByDataDateTime.end 2011
temporal.rangeDescribedByDataDateTime.start 2013
temporal.resource.availableDate 2013-08-01
title.alternative dart_monitoring_apparent_permitivity_cstdr100
title.pattern Where appropriate each resource has been named with the following pattern: DART_<3 character sensor/collection name>_<spatial location>_<StartDateTime YYYYMMDD with optional HHMM>_<endDateTime YYYYMMDD with optional HHMM>_<stage PRO or RAW to refer to processed or raw data>_<other stuff>.<suffix>. Hence, the file DART_T3P_DDCF_20110823_20130106_PRO.csv refers to DART data collected using the T3P Imko soil moisture probes at Diddington Clay Field between 23rd August 2011 and 6th January 2013 which has been processed and is available in a comma separated text format.