HR: 0830h
AN: U31B-0014    [PDF]
TI: Recent Progress with Atmospheric Noise-Reducing Filters
AU: * Hedlin, M a
EM: hedlin@ucsd.edu
AF: Institute of Geophysics and Planetary Physics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0225 United States
AB: Wind noise is one of the key issues facing the community of acousticians who monitor the atmosphere for long-period signals from natural atmospheric phenomena or from man-made sources, such as nuclear weapons tests. Presently, a network of infrasound observing sites is being constructed to provide global coverage of acoustic sources in the atmosphere. It is well known that spatial filters can be used to attenuate noise due to atmospheric turbulence near the recording point and increase the ratio of signal-to-noise. Rosette spatial filters are currently used at the new infrasound monitoring stations and have been found to provide a significant reduction of noise across the frequency band of interest to the acoustic monitoring community. Research continues into modifications to existing rosette filters that might improve their performance. Additional research is providing insight into entirely different filters, such as wind barriers. Some of the monitoring system's array sites are located on oceanic islands at locations where spatially extensive noise filters will not be practical. This practical limitation fuels our interest in effective, spatially compact filtering methods. This presentation gives an overview of the various filters currently being used and research into improvements for these filters and into entirely different filter designs.
DE: 0394 Instruments and techniques
DE: 0399 General or miscellaneous
SC: U
MN: 2003 Fall Meeting