Seismology Division, Royal Netherlands Meteorological Institute, De Bilt, The Netherlands.
J Acoust Soc Am. 2011 Jul;130(1):33-41. doi: 10.1121/1.3596718.
The study of infrasound is experiencing a renaissance since it was chosen as a verification technique for the Comprehensive Nuclear-Test-Ban Treaty. Source identification is one of the main topics of research which involves detailed knowledge on the source time function, the atmosphere as medium of propagation, and the measurement system. Applications are also foreseen in using infrasound as passive probe for the upper atmosphere, taking the field beyond its monitoring application. Infrasound can be conveniently measured with differential microbarometers. An accurate description of the instrument response is an essential need to be able to attribute the recorded infrasound to a certain source or atmospheric properties. In this article, a detailed treatment is given of the response of a differential microbarometer to acoustic signals. After an historical introduction, a basic model for the frequency response is derived with its corresponding poles and zeros. The results are explained using electric analogs. In addition, thermal conduction is added to the model in order to capture the transition between adiabatic and isothermal behavior. Also discussed are high-frequency effects and the effect of external temperature variations. Eventually, the design parameters for differential microbarometers are derived.
次声的研究正在经历一场复兴，因为它被选为全面禁止核试验条约的验证技术。声源识别是主要研究课题之一，涉及声源时变函数、传播介质（大气）以及测量系统的详细知识。人们还预计将次声用作被动探测高空大气的探头，将该领域的应用扩展到监测之外。次声可以用差分微气压计方便地测量。为了能够将记录到的次声归因于某个声源或大气特性，准确描述仪器响应是一项基本需求。本文详细介绍了差分微气压计对声信号的响应。在历史介绍之后，本文推导出了频率响应的基本模型及其对应的极点和零点。使用电模拟来解释结果。此外，还在模型中加入了热传导，以捕捉绝热和等温行为之间的转变。还讨论了高频效应和外部温度变化的影响。最终，推导出了差分微气压计的设计参数。
