Velocity Standard Error; Table 6:3 - Σv Data Types - Xylem SonTek FlowTracker2 User Manual

g) The SNR checks are re-run (Discharge mode and General mode measurement)
to ensure the warnings are set with the most current data.
h) This criterion can be adjusted or disabled under
SNR is primarily a function of the amount and type of particulate matter in the water.
SNR cannot be immediately converted to sediment concentration, it provides an
excellent qualitative picture of sediment fluctuations and with proper calibration, SNR
can be used to estimate sediment concentration.
6.1.2

Velocity Standard Error

Standard Error of Velocity (
velocity data.
a) σV can be directly interpreted as the accuracy of the mean velocity.
b) σV is calculated by dividing the standard deviation of one-second samples by the
square root of the number of samples.
c) σV is normally dominated by real variations in the flow and will vary depending on
the measurement environment (see
σV Data
d) The σV displayed after a point velocity measurement, station and or stations are
Display
completed in both General and Discharge Modes are supplied in
Mode
Discharge
General
σV Data
e) σV is evaluated against number of quality control criteria and at the end of each
Evaluate
velocity point measurement, the following velocity standard error checks are run
FlowTracker2 User's Manual (January 2019)
σV
) is a direct measure of the accuracy of the mean
Table 6-3 –
Reporting Type
σV Point
Review Point
Measurement
Measurement
Mean Station
Review
σV
Station
Mean Section
Discharge
σV
Summary
Beam σV at
Review Point
Point
Measurement
Measurement
Mean Beam
Review
σV at Station
Station
General
Mean σV
Summary
Quality Control
Principle of Operations).
σV
Data Types
Description
X-component velocity standard error.
The station σV is the mean of the X-
component velocity standard error from each
point velocity measurement.
The discharge summary σV is the mean of all
stations average X-component velocity
standard error.
The point measurement σV for each individual
beam (2 or 3 depending on probe type) at the
point measurement.
The station σV is the mean for each individual
beam (2 or 3 depending on probe type) of all
point measurements at a station.
The general summary σV is the mean of all
stations average X-component velocity
standard error.
87
SonTek – a Xylem brand
Settings.
Table 6:3.