YSI SonTek RiverSurveyor, Системное руководство

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SonTek/YSI Inc
RiverSurveyor System Manual (May 1, 2007)
164
E-6. Step 6 – Review Setup Parameters
Press
Ctrl+U
to review the user setup parameters. Briefly review the parameters on all three
pages, but pay particular attention to the following:
•
File Name Prefix
– Is the file name prefix similar to field notes? It is beneficial to use file-
names that are representative of the measurement site.
•
Averaging Interval
– Was the averaging interval set correctly (5-seconds preferable)?
•
Magnetic Declination
– Has a value been entered for magnetic declination, and if so, is the
value correct? Magnetic declination is critical when integrating GPS systems.
•
Water Salinity
– Is the value for water salinity correct for the measurement section? Remem-
ber: 0 ppt for Freshwater; 34.5 ppt for salt/sea water.
•
Transducer Depth Method
– Is the transducer depth method consistent with the field meas-
urement notes?
•
Transducer Depth
– Is the transducer depth consistent with observed field measurements?
•
Profiling Range
– Is the profiling range realistic for the measured section? Would different
profiling parameters have provided a better measurement result (i.e. cell size could have
been larger/smaller, etc.)?
E-7. Step 7 – Velocity Contour Window
Display the Contour Control Box (
View | Show Contour Control Box
).
Select Velocity for Display and Speed for the Component on the Contour Control Box.
Velocity –
Abs Speed
will be displayed above the
Contour Window
(§
7.2.6
).
Look for evidence of reverse or bi-directional flow. This may be indicated by a “band” of zero
velocity that runs across the
Contour Window
. Does the graph make sense? Generally, higher wa-
ter current speeds are found in deeper areas or near the center of the channel.
Select Velocity for Display and Direction for the Component on the Contour Control Box.
Veloc-
ity – Direction
will be displayed above the
Contour Window
.
Look for an area of water that is traveling in the reverse (
≈
180°) direction to the remainder of the
section. Does the graph make sense? Are directions relatively consistent or is the evidence of cir-
culation or eddies?
E-8. Step 8 – Data Quality Window/Bar Chart (time-series parameter displays)
The Data Quality window is a rough gauge of the integrity of the measurement. Look for consis-
tency, spikes/erratic behavior, dropouts, or large fluctuations in the data displayed in this win-
dow as they may have a strong correlation with any anomalies that may have occurred during
data collection. Variables that can be displayed in this window include:
•
Data Quality Index (DQI)
– The DQI is typically higher in shallow water and lower in deeper
water. Generally, the DQI should be below 1.0, though less than 3.0 is acceptable. Parame-
ters that affect the DQI include: water depth vs. number of cells, standard deviation, and
loss of key data sources such as GPS or bottom-track. Sudden spikes are typically due to
lost profiles, bad bottom-track/GPS, or sudden changes in depth.
•
Boat/Water Speed
– Ideally, this ratio should be less than or equal to one. Is the ratio higher
than one? If so, could this have been avoided? What can be done to prevent it for future
measurements? Is there a significant effect on the data?
•
Boat Speed
– Is the boat speed relatively steady and not erratic?