Speed of sound at altitude full#
Speed of sound at altitude series#

further derived Hamilton's equations in three-dimensional spherical coordinates to establish a ray propagation model under the curvature of the Earth. Infrasound modeling in a spherical heterogeneous atmosphere,” J. modified the Hamiltonian and established a ray tracing model in a two-dimensional Cartesian coordinate system, in which the sound pressure amplitude and propagation time estimation were more accurate due to the addition of layered media and a wind velocity correction. Paraxial ray tracing for atmospheric wave propagation,” J. proposed an algorithm and a program for the numerical integral Hamilton method applied to the atmosphere named HARPA. Jones,Ī versatile three-dimensional Hamiltonian ray-tracing program for acoustic waves in the atmosphere above irregular terrain,” Wave Propagation Laboratory, Boulder, CO, 1986. Infrasonic atmospheric propagation studies using a 3-D ray trace model,” in Proceedings 22nd Conference on Severe Local Storm, 4–8 October 2004. proposed a numerical integration method for solving the Hamilton's equations in three dimensions, which could be applied not only to the propagation of electromagnetic waves in the ionosphere but also to long-distance propagation of atmospheric infrasound waves. Jones andĪ versatile three-dimensional ray tracing computer program for radio waves in the ionosphere,” Rural Utilities Service Government Printing Office, Washington, D.C., 1975. (63)90173-9 derived Hamilton's equations in general curve coordinates and created another solution to the ray equation by combining the equations with the acoustic dispersion equation. Based on the Sommerfeld-Runge law and the law of conservation of peaks, Haselgrove and Haselgrove 5,6 5. He simulated the propagation trajectories of rays in a layered medium where the air density and temperature were functions of altitude without considering propagation absorption. (63)90156-9 combined an atmospheric layering model to study the frequency and amplitude constraints using ray propagation theory. Ray tracings of acoustic waves in the upper atmosphere,” J. Assuming that both the sound speed and wind velocity are functions of altitude, he verified that sound waves can reenter the atmosphere. (55)90119-7 derived a theory of acoustic rays by an analogy with geometric optics. Geometrical theory of sound propagation in the atmosphere,” J. conducted a preliminary study on sound rays and found not only that sound wave propagation paths change with different seasons but also that temperature and wind direction are main influencing factors. The propagation of sound to great distances,” Q. Ray tracing is an important method for studying the process of infrasound propagation in the atmosphere.

Speed of sound at altitude full#

However, this method does not make full use of the information of the apparent velocity and ignores the propagation process of the sound wave in the atmosphere, resulting in the inability to obtain the altitude of the infrasound source. At present, researchers in CTBTO countries widely use the azimuth measured by two or more arrays and their geographical coordinates to locate the latitude and longitude of an infrasound source by mapping to the Earth coordinate system. proposed the progressive multichannel correlation (PMCC) method, which optimized a monitoring array and obtained the azimuth and apparent velocity of an infrasound wave reaching the array in different frequency bands. Cansi, “Īn automated seismic event processing for detection and location: The P.M.C.C. Based on existing seismic detection techniques, Cansi 1 1.

Speed of sound at altitude series#

To this end, a series of studies has been developed, including infrasound signal processing methods and propagation theory algorithms. Due to its low frequencies and low atmospheric attenuation, infrasound has gradually become one of the significant approaches used to monitor nuclear tests. Since the 1990s, according to the requirements of the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) of the United Nations, there has been an increasing demand for monitoring nuclear tests worldwide.