MEASUREMENTS OF ATMOSPHERIC ATTENUATION AT ULTRASONIC FREQUENCIES AND THE SIGNIFICANCE FOR ECHOLOCATION BY BATS
MEASUREMENTS OF ATMOSPHERIC ATTENUATION AT ULTRASONIC FREQUENCIES AND THE SIGNIFICANCE FOR ECHOLOCATION BY BATS
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DOI：
10.1121/1.387529
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发表时间：
1982-01-01
影响因子：
2.4
通讯作者：
SIMMONS, JA
中科院分区：
文献类型：
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作者：
LAWRENCE, BD;SIMMONS, JA
在25℃的实验室条件下对通过大气传播的声音的吸收。 C 和 50% 相对湿度是在 30-200 kHz 的频率下测量的。超声波通过空气的衰减效果范围为 30 kHz 时的 0.7 dB/m 至 200 kHz 时的 8 dB/m。这些测量结果证实了理论预期和观察结果，即大气衰减在较高频率下逐渐变得更加严重，并且大气充当低通滤波器，用于传导蝙蝠回声定位频率范围内的声音。不同种类的蝙蝠使用此频率范围的不同部分，并且主要发射 > 100 kHz 声纳信号的蝙蝠会遇到 > 3 dBm/m 的特别严重的衰减。由于在如此高的频率下回声定位的操作距离受到极大限制，使用这些更高频率的蝙蝠必须承受比远距离目标检测更高的紧迫生态压力。
The absorption of sound propagating through the atmosphere under laboratory conditions of 25.degree. C and 50% relative humidity was measured at frequencies from 30-200 kHz. The attenuating effect on the passage of ultrasonic sounds through air ranged from 0.7 dB/m at 30 kHz to 8 dB/m at 200 kHz. These measurements confirm theoretical expectations and observations that atmospheric attenuation is progressively more severe at higher frequencies and that the atmosphere acts as a low-pass filter for conducting sounds in the frequency range used for echolocation by bats. Different species of bats use different portions of this range of frequencies, and bats emitting sonar signals predominantly > 100 kHz encounter especially severe attenuation of > 3 dBm/m. With the greatly restricted operating distances for echolocation at such high frequencies, bats using these higher frequencies must be under compelling ecological pressures of a higher priority than long-range detection of targets.