Detection and Azimuth Estimation by Infrasonic Arrays as a Function of Array Aperture and Signal Coherence

摘要

The Infrasound Experts Group of the Geneva Conference on Disarmament Ad Hoc Committee on a Nuclear Test Ban has recommended an infrasound array design consisting of four elements, with three elements forming an equilateral triangle and the fourth at the center of the triangle. The Experts recommended that the sides of the triangle be in the range of 1 to 3 kilometers (km). In this report, correlation as a function of period and sensor spacing, and signal- to-noise ratios (S/N) as a function of period are estimated from atmospheric data from nuclear explosions of 2.2 and 2.6 kilotons (kt) recorded at sensors with spacings near 1 km and at distances from the explosions of 700 km. The correlation estimates are found to be consistent with parameters describing the spread of the signal in wavenumber space as discussed by Blandford (1997). These parameters were first estimated by Mack and Flinn (1971) for events of much larger yield at larger distances, longer period, and greater inter-sensor spacings. Data at 10 km spacing from a 2.2 kt event at a distance of 2200 km is found to be consistent with the Mack and Flinn parameters.