Manual – Starflow QSD Model 6527B and 6537A
Unidata Manual - 6527B and 6537A Starflow QSD User Manual 08 05 2023.docx
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17.11.
Effects of Surface Ripples
In shallow water, the presence of ripples or small waves on the surface can cause
complications. The ripples may be caused by wind or be a feature of the channel caused by
obstructions in the channel or by irregularities on the bank. Ripples will be moving at a
different velocity to the water.
In shallow and clean water, the Starflow QSD can clearly see the surface. As the ripples
move, they present a varying effect on the Doppler signal. At times the ripples will be
positioned so that the carrier reflects away from the Starflow QSD. A minor signal is
detected, but many more signals are detected from the water, and a correct velocity is
measured.
When the ripples move slightly, one can become positioned such that it becomes an
“acoustic mirror”, reflecting back a powerful signal and dominating the signals from the
channel. The median velocity will be biased toward the ripple velocity and will be incorrect.
