RD Instruments Home of the ADCP Measuring Water in Motion and Motion in Water THETIS Waves Data QA RD Instruments Home of the ADCP

Acoustic D oppler Solutions

RD InstrumentsHome of the ADCP

Measuring Water in Motion and Motion in WaterAcoustic D oppler SolutionsAcoustic D oppler Solutions

THETIS Waves THETIS Waves Data QAData QA

Acoustic D oppler SolutionsRD RD

InstrumentsInstrumentsHome of the Home of the

ADCPADCP




THETIS WAVES DATA QA

1.1. RD Instruments OverviewRD Instruments Overview

2.2. Capability of ADCP waves ArrayCapability of ADCP waves Array

3.3. Initial Data Processing + Interpretation Initial Data Processing + Interpretation

4.4. Data Recovery + Re-ProcessingData Recovery + Re-Processing

5.5. Re-Processed Data QARe-Processed Data QA



RD InstrumentsHome of the

ADCP

Measuring Water in Motion and Motion in Water

Company & CapabilitiesCompany & Capabilities




1981: First commercial ADCP in the world1981: First commercial ADCP in the world 1985: First river discharge ADCP1985: First river discharge ADCP 1991: Broadband ADCP patent1991: Broadband ADCP patent 1994: Phased array ADCP patent1994: Phased array ADCP patent 1995: Workhorse ADCP. 1995: Workhorse ADCP. 1999: ADCP waves array patent1999: ADCP waves array patent 2001: Horizontal ADCP2001: Horizontal ADCP 2002: ZedHed: Shallow-depth ADCP2002: ZedHed: Shallow-depth ADCP 2003: StreamPro, Channel Master2003: StreamPro, Channel Master 2004: Waves from a Horizontal2004: Waves from a Horizontal

History of InnovationHistory of Innovation




Business UnitsBusiness Units

Marine MeasurementsMarine Measurements Underwater NavigationUnderwater Navigation Water ResourcesWater Resources Man-made channelsMan-made channels




ADCP Waves Array Method ADCP Waves Array = remote sensed array of ADCP Waves Array = remote sensed array of

sensorssensors 12x near surface “orbital motion” senors – 12x near surface “orbital motion” senors –

Array processing for directionArray processing for direction 3x independent estimates of non-directional 3x independent estimates of non-directional

informationinformation Easy standard processingEasy standard processing Powerful data recovery capabilityPowerful data recovery capability Automated data recovery – June 2005Automated data recovery – June 2005




Acoustic Doppler Solutions

Constructing the ARRAY?




PUV Processing Provides Biased Measurements

Direction #1

Directi

on #2

Biased Direction

Array Processing Allows Multiple Directions to be Measured at a Single Frequency

Array Processing Avoids Bias in Direction Statistics




Deployment Guidelines

Bottom Mounted, for Tide, Currents + Multi-Bottom Mounted, for Tide, Currents + Multi-Directional WavesDirectional Waves

In Line Frame, Mooring, Upwards Looking for In Line Frame, Mooring, Upwards Looking for Currents + Uni-Directional Waves Currents + Uni-Directional Waves

Real Time or Self Contained OperationReal Time or Self Contained Operation Frequency ChoiceFrequency Choice

Bottom Mounted, for Tide, Currents + Multi-Bottom Mounted, for Tide, Currents + Multi-Directional WavesDirectional Waves

In Line Frame, Mooring, Upwards Looking for In Line Frame, Mooring, Upwards Looking for Currents + Uni-Directional Waves Currents + Uni-Directional Waves

Real Time or Self Contained OperationReal Time or Self Contained Operation Frequency ChoiceFrequency Choice ADCP

Frequency (kHz)

Depth Range (m)

1200 2.5 - 15600 5 - 48300 10 - 100




Deployment Guidelines

Frequency Decay With Depth

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

5.0 10.0 20.0 40.0 80.0 120.0

Depth

Min

imu

m M

ea

sura

ble

W

ave

Pe

rio

d

Directional (array) Non Directional (velocity) Non-Directional (pressure)




WavesMon for Data Processing

Process self contained dataProcess self contained data Extract currents + wave dataExtract currents + wave data Generate output filesGenerate output files Real-time data collection + Real-time data collection +

display capabilitydisplay capability Generate real time graphic Generate real time graphic

data outputdata output




WavesMon Auto Setup (1)

Click Auto Setup. Click Auto Setup. At the ADCP Data At the ADCP Data

File dialog box, File dialog box, select the data file select the data file to be opened by to be opened by using the Browse using the Browse button. button.

Click Open. Click Open.




Enter the ADCP Enter the ADCP Altitude Above Altitude Above Bottom when the Bottom when the ADCP was ADCP was deployed. deployed.

Click OK.Click OK.





Click GO Click GO





Data QA—Check List

Use WaveView to verify data quality ( *.wvs file) Check for reasonable parameters in the time series

(Hs, Tp, Dp) Check error log

Check for agreement in 1-D spectra

Check for reasonable high frequency cutoff

Check for reasonable directional spectra




Check for reasonable parameters in the time series (Hs, Tp, Dp)

Much Lost data = ISSUE!Much Lost data = ISSUE!




Check Error Log (wmerrlog.txt)

Near surface bin (#2) has low percentage of good samples. 90 % good is required to complete processing of Velocity Array




Reasons for bad near surface bin in array?

Check quality of ensemble averaged velocity data

Check for excessive tilts Check readings of pressure

sensor relative to surface track




Check Quality of Ensemble Averaged Velocity Data

Low Error Velocity = Good near surface data




Check For Excessive Pitch + Roll

<5 degrees pitch + roll = Good hardware deployment




Check readings of pressure sensor relative to surface

track (1) Re-Process using expert option – use surface track for depth Compare results with pressure sensor based depth measurement (ascii log file format 5) Calculate difference (excell)




Check readings of pressure sensor relative to surface

track (2) Result = 1217 mm average difference

(pressure – surface) Depth During Wave Burst

0

2000

4000

6000

8000

10000

12000

14000

1 17 33 49 65 81 97 113 129 145 161

Wave Burst #

Dep

th (m

m)

Pressure

Surface Track




Re-Process (1) Add pressure sensor offset -1217 mm Use pressure sensor for Depth Use bottom 2 bins in array

A cous tic D opp le r S o lu tions





Use WaveView to verify data quality ( *.wvs file) Check for reasonable parameters in the time series (Hs, Tp,

Dp) Check error log


Check for reasonable high frequency cutoff – EXPECT ERRORS in Default Values – Deeper Bins –More Signal Attenuation – Must decrease high frequency Cutoff





Check High Frequency Cutoff Incorrectly set high frequency cutoff will result in high Hs, incorrect Tp, incorrect Dp Proper HF cutoff for Vspec = 0.38 hz




Re-Process (2) Add pressure sensor offset -1217 mm Use pressure sensor for Depth Use bottom 2 bins in array Change High Frequency Cutoff to 0.38 hz

A cous tic D opp le r S o lu tions





Use WaveView to verify data quality ( *.wvs file) Check for reasonable parameters in the time series

(Hs, Tp, Dp) Check error log


Check for reasonable high frequency cutoff





Check for reasonable parameters in the time series (Hs, Tp, Dp)




Check error log One surface tracking burst “bad”One surface tracking burst “bad”




Check for agreement in 1-D spectra / Check for reasonable

high frequency cutoff




Check Directional Spectra




Conclusion

Pressure sensor in errorPressure sensor in error Data recovered with advanced processing optionsData recovered with advanced processing options Detailed pressure sensor inspection requiredDetailed pressure sensor inspection required Possible re-calibrationPossible re-calibration RDI Europe Field Serivce to adviseRDI Europe Field Serivce to advise




ADCP Waves Array Method ADCP Waves Array = remote sensed array of ADCP Waves Array = remote sensed array of

sensorssensors 12x near surface “orbital motion” senors – 12x near surface “orbital motion” senors –

Array processing for directionArray processing for direction 3x independent estimates of non-directional 3x independent estimates of non-directional

informationinformation Easy standard processingEasy standard processing Powerful data recovery capabilityPowerful data recovery capability Automated data recovery – June 2005Automated data recovery – June 2005

Documents

RD Instruments Home of the ADCP Measuring Water in Motion and Motion in Water THETIS Waves Data QA RD Instruments Home of the ADCP