skytem at the extended test site
DESCRIPTION
Validating SkyTEM Data Against Ground-based TEM Data at the Danish National Test Site by Upward Continuation. Nikolaj Foged*, A.V. Christiansen**, and Esben Auken* *HydroGeophysics Group, Department of Earth Sciences, Aarhus University, Denmark - PowerPoint PPT PresentationTRANSCRIPT
Nikolaj Foged*, A.V. Christiansen**, and Esben Auken**HydroGeophysics Group, Department of Earth Sciences, Aarhus University, Denmark **Geological Survey of Denmark and Greenland - GEUS
Validating SkyTEM Data Against Ground-based TEM Data at the Danish National Test Site by Upward Continuation
z-receiver
z-receiver coil
x-receiver coil
Transmitter frame
instrumentation
• Super low moment (SLM), 45 000 Am2
• High moment (HM),180 000 Am2
• SLM + HM is applied sequential
SkyTEM at the extended Test site
Laser altimeters
inclinometers,pitch and roll
SkyTEM, extended Test site - dataset
• Altitudes: 15 m, 25 m, 35 m
• Four repetitions per line and altitude. Total of 12 repetitions per line
• Standard processing and inversion is applied
• Sounding/model spacing: 20 m
• Independent LCI-inversion of each line repetitions
1 km
Validation of SkyTEM - model space
Validation of SkyTEM - model space
• Repeated line, altitude 15 m
Line1A
Line 1B
Validation of SkyTEM - model space
• Repeated line, altitude 15 m
• Background: SkyTEM, Line 1A
• Front bars: SkyTEM, Line 1B
Line1ALine 1B
Validation of SkyTEM - model space
• Repeated line, altitude 15 m and 35 m
15 m
35 m
Validation of SkyTEM - model space
• Repeated line, altitude 15 m and 35 m
• Background: Altitude 15 m
• Front bars: Altitude 35 m
15 m35 m
Validation of SkyTEM - model space
• Comparison with ground based TEM: Altitude 15 m
SkyTEM
Ground TEM
Validation of SkyTEM - model space
• Comparison with ground based TEM: Altitude 15 m
• Background: SkyTEM, altitude 15 m
• Front bars: Ground based TEM
• Background: Altitude 35 m
• Front bars: Altitude 15 m
Validation of SkyTEM - model space
• Comparison with ground based TEM: Altitude 15 m, 35 m
• Background: SkyTEM, altitude 15 m, 35 m
• Front bars: Ground based TEM
15 m
35 m
Validation of SkyTEM - data space
Repeatability, 15 m, data space
115 sAltitude ~15 m
Raw data
Repeatability, 15 m, data space
115 sAltitude ~15 m
Raw data
Repeatability, 15 m, data space
115 sAltitude ~15 m
Raw data
Repeatability, altitude 15 m
115 sAltitude ~15 m
Raw data
Upward continuation to a nominal height
Forward 23.1 m, 25 m
Model Calculate correction factor per time gate
Data, 25 m
Apply correction factor to data
• How ?
Data, 23.1 m
Inversion
Upward continuation of ground based TEM
Forward, SkyTEM system, 25 m
Reference model
SkyTEM refe-rence responce
• To compare/evaluate the SkyTEM system with the ground based TEM in data space
• How ?
Ground TEM
Inversion
Repeatability, nomial altitude 15 m
115 s
Nominal altitude
Raw data
Repeatability, nomial altitude 15 m
14 s
3.6 ms
115 s
Repeatability, nomial altitude 15, 25, 35 m
115 s
Match to reference section, 15, 25, 35 m
115 s
Reference response
Reference response
Reference response
Match to reference section, 15 m
14 s
3.6 ms
115 s
Reference response
Reference response
Reference response
Conclusion• Calibration on the National test site insures
consistence mapping results
• Validation of the SkyTEM system
Repeatability - same altitude Repeatability - different altitudes Match to ground based TEM / reference
section
• Also validation of:• the detailed and carefull processing scheme • the high precision inversion code (em1dinv)
• Validation is demanded for any TEM-system to participate in the Danish groundwater mapping campaign
All data to nominal height of 25 m