The use of in situ infrasound calibration to correct wave parameter estimation

Abstract

As part of the Comprehensive Nuclear-Test-Ban Treaty (CTBT), the International Monitoring System (IMS), which includes infrasound stations, has been established to monitor nuclear testing, as well as many other infrasound sources of interest to the scientific community. To minimize the effects of wind-noise, wind-noise reduction systems (WNRS) are installed as part of each sensor. In order to provide the best wave parameter (azimuth, trace velocity, amplitude) estimates, the response of the WNRS must be properly taken into account. Therefore, it is important to perform an in-situ calibration of the sensor using a co-located reference sensors and ambient signals to determine this response. This in-situ calibration can be used to monitor the status of the sensors, and provide feedback to the station operators. Experiments were performed at the IS26 site in Germany using a temporary WNRS to provide quantitative measurements of the effects of the WNRS and its calibration on the wave parameter estimation. These calibration results were used to provide corrections to the raw signal data for retrieval of the corrected wave parameters and were compared to the IS26 measurements, demonstrating that accurate measurements can be retrieved using the in-situ calibration.