Processing Parameters in TRDI SxS Pro

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Detailed Description

In this video, we will discuss the Processing dialog in TRDI SxS Pro. Note: Use of trade names is for descriptive purposes only, and does not imply endorsement by the USGS. For additional videos in this series, visit the following link: https://www2.usgs.gov/humancapital/ecd/hydrotube/hydrotube-ADCP.html
 

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Image Dimensions: 480 x 360

Date Taken:

Length: 00:03:07

Location Taken: Augusta, ME, US

Transcript

Hi, my name is Nick Stasulis and I work with the Maine Office of the New England Water Science Center. In this video, we will discuss the Processing dialog in TRDI SxS Pro.

The Processing dialog has several useful settings that you might need during collection and review of data in SxS Pro and can be accessed in the Configure menu, or by pressing F3. These settings apply to all verticals that make up your measurement. Rather than cover each setting in detail, we will discuss them generally and highlight the settings most commonly used. Detail on all of the processing settings can be found in Chapter 7 of the SxS Pro User Guide.

The data screening settings allow you to control which data is used or not used to compute velocity and discharge. The mark bad below bottom and sidelobe settings only control what is displayed in the software, not discharge calculations. The screen depth setting is commonly used to remove erroneous depth readings by filtering out depths that differ by more than 75%, which are typically due to reflections of the depth beam.

The thresholds allow screening of data based on error and vertical velocities, though it’s important to note the water track error velocity threshold is applied to each vertical individually and must be changed in the vertical information. A commonly used setting here is the good ensemble in cell field. Many times, you’ll see an erroneous depth cell near the bottom of a vertical that is only being computed by one or two ensembles out of the 30-40 total. This value can be changed to a higher number, which forces the software to use the number of ensembles you choose for computing a depth cell for a vertical.

The speed of sound fields are used if salinity is measured in your cross section or if the ADCP computed speed of sound is not reliable and needs to be fixed for the measurement. A case where using a fixed speed of sound is common is when the ADCP’s thermistor is not reading correctly or is not equilibrated. In this case, compute a speed of sound using the reference temperature reading and enter it here.

The reference should be left at ADCP, do not select bottom track here. The power exponent for all verticals is changed here, but remember the extrapolation method is changed for each vertical. The discharge method is left at mid-section. The velocity method will typically be left at magnitude for an open water measurement and y-velocity for an ice measurement. Remember that magnitude requires the user to enter a flow angle, while y-velocity requires the unit to be held with beam 3 downstream and perpendicular to the cross section.

If beam 3 was not aligned correctly for all verticals, you can enter a beam 3 misalignment here when using y-velocity.

If you are applying several changes, you can use the apply button here after each, or simply hit OK after making all of your changes. Be sure these changes are documented in measurement notes and made before finalizing the measurement and importing into SVMobile.