TY - GEN
T1 - Validation of High-resolution ADCP Measurements of TKE Dissipation Influenced by Waves
AU - Marchetti, Elias
AU - Culverhouse, Thomas
AU - Comerford, Thomas
AU - Nimmo-Smith, Alex
N1 - Publisher Copyright:
© 2024 IEEE.
PY - 2024
Y1 - 2024
N2 - This study evaluates the capability of the new Origin 600 (Sonardyne) high-resolution five-beam Acoustic Doppler Current Profiler (ADCP) to measure turbulence in shallow coastal waters influenced by surface waves. Evaluation was done through comparison between bedframe-mounted, upwards-facing ADCP data and a free-falling MicroStructure Sampler (MSS) shear probe, in turbulent flow conditions characteristic of the Tamar River channel in Plymouth Sound, UK. While commonly used to measure water column velocity, the low resolution of conventional ADCPs severely reduces their ability to estimate finescale turbulence. The new Sonardyne Origin 600 ADCP allows for much higher along-beam resolution of up to 1.2 cm, granting an unprecedented outlook into water column turbulent characteristics. ADCP-based Turbulent Kinetic Energy (TKE) dissipation estimates were computed through a second order structure function for each ADCP beam. Sets of 5, 11 and 17 radial separations and spatial velocity averaging combinations of 10, 25 and 50 cells per bin were compared to reference MSS-measured dissipation data, for six measurement segments ranging from 10 to 18 minutes. Surface wave field conditions above the ADCP unit were evaluated through power spectrum density performed on wave heights computed from ADCP echo intensity, estimating wave induced TKE dissipation contamination. Although further research is required to fully evaluate the accuracy of their TKE dissipation estimations, this study found that a high-resolution ADCP is a versatile tool to continuously evaluate finescale turbulence in shallow and energetic water columns, especially when compared to a lower-resolution MSS. High-resolution ADCP data can also be binned after capture, allowing for a tailored approach when measuring differing water column conditions.
AB - This study evaluates the capability of the new Origin 600 (Sonardyne) high-resolution five-beam Acoustic Doppler Current Profiler (ADCP) to measure turbulence in shallow coastal waters influenced by surface waves. Evaluation was done through comparison between bedframe-mounted, upwards-facing ADCP data and a free-falling MicroStructure Sampler (MSS) shear probe, in turbulent flow conditions characteristic of the Tamar River channel in Plymouth Sound, UK. While commonly used to measure water column velocity, the low resolution of conventional ADCPs severely reduces their ability to estimate finescale turbulence. The new Sonardyne Origin 600 ADCP allows for much higher along-beam resolution of up to 1.2 cm, granting an unprecedented outlook into water column turbulent characteristics. ADCP-based Turbulent Kinetic Energy (TKE) dissipation estimates were computed through a second order structure function for each ADCP beam. Sets of 5, 11 and 17 radial separations and spatial velocity averaging combinations of 10, 25 and 50 cells per bin were compared to reference MSS-measured dissipation data, for six measurement segments ranging from 10 to 18 minutes. Surface wave field conditions above the ADCP unit were evaluated through power spectrum density performed on wave heights computed from ADCP echo intensity, estimating wave induced TKE dissipation contamination. Although further research is required to fully evaluate the accuracy of their TKE dissipation estimations, this study found that a high-resolution ADCP is a versatile tool to continuously evaluate finescale turbulence in shallow and energetic water columns, especially when compared to a lower-resolution MSS. High-resolution ADCP data can also be binned after capture, allowing for a tailored approach when measuring differing water column conditions.
KW - ADCP
KW - Shear probe
KW - Turbulent Kinetic Energy Dissipation
KW - Wave Energy
KW - Wave Orbital Velocity
KW - Wave Spectrum
UR - http://www.scopus.com/inward/record.url?scp=85193966008&partnerID=8YFLogxK
U2 - 10.1109/CWTM61020.2024.10526338
DO - 10.1109/CWTM61020.2024.10526338
M3 - Conference proceedings published in a book
AN - SCOPUS:85193966008
T3 - 2024 IEEE/OES 13th Current, Waves and Turbulence Measurement, CWTM 2024
BT - 2024 IEEE/OES 13th Current, Waves and Turbulence Measurement, CWTM 2024
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 13th IEEE/OES Current, Waves and Turbulence Measurement, CWTM 2024
Y2 - 18 March 2024 through 20 March 2024
ER -