Explaining global patterns of microbarom observations with wave action models

Abstract : S U M M A R Y We present a methodology to model the spatio-temporal variations of microbarom detections at a global scale. Our model combines the source term resulting from the non-linear ocean-wave interaction and a simplified description of the long-range infrasound propagation through the stratospheric waveguide. We compare model predictions with observations at infrasound stations of the International Monitoring System between 2008 and 2009. Our results show a first-order consistency between the observed and modelled trends of microbarom backazimuth detections for most stations. Taking into account stratospheric wind effect on the infrasound propagation systematically improves the fit between the observations the model predictions. However, correctly predicting patterns of weekly variation of detections turns out to be more challenging and would require further improving the source and the propagation models. Short-term and regional quantitative comparisons could then be carried out based on the metrics developed in this study.