Temperature inversion layers refract sound away and create silent zones

Evidence

Colder air aloft means slower sound propagation speed there. If the temperature going aloft does not change too fast, the impedance and sound speed will gradually change, meaning little or no reflection will occur as sound penetrates from below. As we know, waves refract toward the region of slower propagation speed. From a source on the ground, sound initially traveling toward Kean and Randolph could have been bent skyward and passed over their heads by many hundreds or perhaps thousands of feet. They would be in a silent zone. — Eric J. Heller, Why You Hear What You Hear- An…, 2596

Categorization

Category: Causal Relationships

• DEFINE: Explains the mechanism by which a gradual thermal gradient bends sound toward slower-speed regions without reflection, producing near-total silence.

Related

• Lower temperature slows the speed of sound predictably via thermal molecular motion (similarity 0.83)
• Sound refracts toward slower-speed regions over long outdoor distances (similarity 0.82)
• Refraction, unlike wall diffraction, can create near-total acoustic silent zones. (similarity 0.82)
• Temperature refraction makes distant concertgoers hear more noise than nearby ones (similarity 0.82)
• Waves always refract toward regions of slower wave speed (similarity 0.80)
• Sound bends like light because temperature changes its speed. (similarity 0.80)
• Wind gradients refract sound toward slow regions and extend its range (similarity 0.80)
• Sound from one explosion skipped over near regions and reached far ones (similarity 0.79)
• Wind speed gradients, not wind itself, refract sound and break reciprocity (similarity 0.79)
• Sound speed in air varies only with the square root of absolute temperature (similarity 0.79)
• Temperature layers in water can hide submarines from sonar. (similarity 0.79)
• Downwind sound is bent downward and waveguides along the ground, gaining intensity (similarity 0.79)
• Reflected sound waves interfere with direct waves to create frequency peaks and dips (similarity 0.79)
• Speed of sound depends on temperature, not pressure (similarity 0.79)
• Wind bends sound waves because air velocity changes with height (similarity 0.79)

Broader Connections

• Lower temperature slows the speed of sound predictably via thermal molecular motion #expands (0.85) — Eric J. Heller, Why You Hear What You Hear- An…, 174