Towards a near real-time estimate of the detection capability of the global IMS infrasound network (Invited)

A global scale analysis based on available detection lists for all operating IMS infrasound stations confirms that the primary factor controlling signal detectability is the seasonal variability of the stratospheric wind circulation. At most arrays, ~80% of the detections in the 0.2 to 2 Hz bandpass are associated with downwind propagations. The seasonal transition in the bearings and number of detections between easterly and westerly directions is presented. The detection capability of the IMS network is assessed using near-real time atmospheric updates and station-dependent wind noise models. Compared with previous studies, a significant enhancement is the incorporation of station noise characterization. Accurate estimates of the noise levels are obtained by calculating Power Spectral Density (PSD) curves for each station at various times of day for each month. This information is useful in determining network detection capability. Comprehensive ground-truth databases provide a statistical approach for evaluating the potential of infrasound monitoring. Accidental and calibration explosions are analysed and used here as benchmark for validating the calculated threshold maps. Such studies would help to optimize the siting and maintenance of infrasound arrays with respect to both the number and configuration in order to monitor infrasonic sources of interest. They are an important step to enable a successful monitoring regime for atmospheric or surface events to act as an effective verification tool in any future enforcement of the CTBT.