SonTek, a Xylem brand
154
RiverSurveyor S5/M9 System Manual (February 2013)
automatically, the software applies the .ctd file collected closest to the start of the discharge
measurement. After applying the sound speed correction you can instantly view the effect of
the correction on the discharge calculation.
Figure 139. CastAway CTD Sound Speed Correction and UTM Track Location
Summary
Using CTD measurements to apply sound speed corrections to ADP data helps to further im-
prove the measurement accuracy. ADP discharge measurements in rivers with large cross-
sectional profiles and areas with high stratification such as estuaries will benefit the most from
sound speed corrections. The fast response thermistor of the CastAway also ensures accurate
temperature data required for all velocity measurements. The CastAway CTD and RiverSur-
veyor integration is a user-friendly way to apply sound speed corrections to ADP measurements
and increase ADP measurement accuracy.
References
SonTek, 2010, CastAway User’s Manual 1.3. [Available for download at http://www.sontek.com.]
SonTek, 2011, RiverSurveyor S5/M9 System Manual. [Available for download at
http://www.sontek.com.]
SonTek, 2011, Technical Note: Phased Array and Velocity Measurements. [Available online at
http://www.sontek.com/pdf/technotes/PhasedArrayRangeAndVelocity.pdf.]
SonTek, 2011, Technical Note: Range, velocity, Sound Speed and Snell’s Law. [Available
online at http://www.sontek.com/pdf/technotes/VelocityRangeAndSnellsLaw.pdf.]
NOAA Office of Coast Survey, 2011, Field Procedures Manual. [Available online at
http://www.nauticalcharts.noaa.gov/hsd/docs/Field_Procedures_Manual_May_2011.pdf]
