Glossary - R
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R

RAFOS floats
floating instruments designed to move with a current and track the current's movements
rainbow trout
Oncorhynchus mykiss
ramp-up
gradually increasing the sound source level
rarefaction
The instantaneous, local reduction in density of a gas or other medium resulting from passage of a sound wave.
receiver
something that listens for or receives sound; it may or may not record the sound
receiver-operating-characteristic (ROC) curve
a curve that plots the cumulative distribution functions of the false-alarm probability and the detection probability on the x-axis and y-axis, respectively, to select the optimal detection threshold.
recess
hole, corner or niche. For example, a rock recess, a place surrounded by rocks where a fish can hide
rectified diffusion
when acoustic energy causes supersaturated gas to be pumped into an existing small bubble, making the bubble increase in size
red drum
Sciaenops ocellatus
red grouper
Epinephelus morio
reflected wave
the wave moving away from the reflector
reflection
the deflection of the path of a sound wave by an object or by the boundary between two media
reflector
any boundary between two media that causes the reflection of a wave
refraction
the bending of a sound wave towards a region of slower sound speed
repertoire
Suite of behaviors that an animal may use in different contexts; in this case, the number of call types that have been distinguished based on categorization of vocal behavior.
resonance
when sounds of specific frequencies cause air- or fluid-filled organs to vibrate with amplitudes that are large compared to the amplitude of incoming soundwaves
resonator
something that fills with sound and acts as a natural amplifier
rete mirabile
a tightly packed bundle of capillaries which works with the gas gland to force gases into the bladder
reverberation
echo
ringed seal
Phoca hispida
rip current
A strong, narrow surface current that flows rapidly away from the shore, returning the water carried shoreward by waves.
Risso's dolphin
Grampus griseus
roll
the rotation of a vessel about its longitudinal (front/back) axis.
root-mean-square pressure
the square root of the average of the square of the pressure of the sound signal over a given duration. Root-mean-square is often abbreviated rms
rorquals
whales of the family Balaenopteridae which includes humpbacks, sei, minke, fin, blue and Bryde's whales. They have throat pleats or ventral grooves that expand when the whales gulp large amounts of water while feeding.
rostrum
upper jaw of whales that is elongated and looks like a beak