Basic Field Review of TRDI SxS Pro Data

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Detailed Description

This video discusses the basic field review procedures for midsection ADCP data collected in TRDI SxS Pro.


Date Taken:

Length: 00:06:42

Location Taken: Augusta, ME, US


Hi, my name is Nick Stasulis and I am a hydrologic
technician with the Maine office of the New

England Water Science Center.

I’d like to discuss the basic field review
procedures for a midsection measurement collected

in SxS Pro with TRDI ADCPs.

-Let’s start in the Measurement Information

The information here is for documentation
purposes only, and entries here do not alter

discharge computations, but this is a useful
place to scan the ADCP hardware and firmware

settings, as well as the configuration.

Using the arrow buttons in the toolbar, or
the control left and right keys, you can scroll

through the verticals and see the configuration
for each.

Look for consistency and ensure any purposeful
changes are noted in the field notes.

-Also in the field notes, confirm the water
temperature and ADCP readings were within

2 deg Celcius before the measurement began.

This should be documented in the acoustic
channel notes in SVMobile.

-In the Playback Screen we are presented with
lots of information.

On the left, there is tabular information
that corresponds to each vertical, as well

as the entire measurement.

To change the vertical displayed here, click
on a vertical in the contour view, or use

the playback controls.

Here, you can evaluate the coefficient of
variation for the measured velocity and the

standard deviation of the velocity direction.

More information on both of these fields can
be found in the podcast using the link shown.

For both, the lower the values, the better
the data quality, in general.

Also look for consistency in the temperature
for each station as it should be stable.

-Scan the contour plot to ensure each station
is ideally less than 5% of the total flow,

and look for consistency in velocity, stationing
and channel depth.

Ensure consistency from station to station,
but also look at consistency within a vertical.

If there are bins in the contour plot that
appear to be significantly different than

others in the area, consider screening these
out, something that will be covered in an

upcoming screencast on common issues with
SxS Pro data.

-Angles in SxS Pro are either entered manually
by the user when using the magnitude velocity

method, or measured automatically by the software
if the unit is held at a fixed orientation

using the y-velocity method (which is typically
only used during ice measurements).

Scan the angles for consistency, and ensure
they make sense based on your knowledge of

the site and flow conditions.

Using magnitude velocity method, errors are
attributed to poorly measured or incorrectly

entered angles by the user.

Using y-velocity method, errors are likely
attributed to the user not orienting the unit

properly during data collection.

Ideally, such issues would be identified and
corrected during data collection.

-Starting on either edge, scan through each
vertical and look at the intensity and velocity

profile plots.

In the intensity plot, look for large inconsistencies
or spikes and use the velocity profile plot

to determine if the extrapolation methods
look reasonable based on the measured data

and if the measured data shows a reasonable
vertical profile.

A separate screencast will cover evaluating
extrapolation in more detail.

-Double clicking any station will bring up
information specific to the vertical.

Scan the ice, water surface and ADCP entries,
as applicable and confirm the water depth


Much of this information can be view visually
on the contour plot, as well.

The velocity profile type can also be changed
for each vertical, though it should likely

be consistent for all verticals.

-If obvious errors are present in the velocity
data, the water track error threshold can

be changed for each vertical here, as well.

-The verticals details/selection view allows
you to compare the depth, velocity, area,

velocity coefficient of variation, the velocity
direction, ADCP depth and other fields from

one station to the next.

Clicking the green arrows here will expand
the information shown.

Note that depending on the unit and deployment
the velocity direction might not be meaningful

or comparable.

This is particularly the case when using a
StreamPro without a compass.

-When expanded this table will give you even
more details on the mode, velocity profile,

number of good cells, and other settings.

Any aborted verticals, or verticals with errors
that cannot be screened should have the “Use”

box unchecked.

Some users have reported issues with stations
that were seemingly collected without issue

not being checked on this table.

Scan the table and ensure the stationing makes
sense based on the data you collected.

During data collection, it’s very important
to check this table and ensure verticals are

being saved as intended due to this potential

-Bring up the Processing dialog using the
F3 key and ensure the data screening settings

and processing settings are set appropriately.

For example, ensure the velocity method is
set correctly based on how you collected the

data and accounted for angles during the measurement.

This is also where you set the extrapolation
exponent and thresholds that are applied to

all verticals.

-Lastly, bring up the Discharge Measurement
Summary Report by selecting File > XML Summary

File > View and scan the measurement and ADCP
setup information, summary information and

the details for each vertical if this wasn’t
already done.

After conducting this preliminary review,
address any issues you might find, as needed.

Some issues may be resolved by simply changing
software settings or entries (such as an incorrectly

entered station location), but some issues
may require data to be re-collected.

Once the measurement has been satisfactorily
reviewed, export the xml summary file to import

into SVMobile.

In the next screencast, we will show some
examples of issues commonly identified in

the SxS Pro software.