Modelling infrasonic ocean ambient noise using NWP and lidar observations in southern Argentina

In routine processing of infrasound data of the International Monitoring System, coherent ocean ambient noise with dominant frequencies ranging from 0.1 to 0.5 Hz appears in overlapping frequency bands. These signals, so-called microbaroms, originate from complex wave interactions. In this study, microbarom detections are used as calibration signals, and their amplitudes at the Argentinian infrasound station IS02 are modelled based on operational ocean wave interaction simulations and a semi-empirical attenuation relation. This relation strongly depends on the middle atmosphere (MA) dynamics. Previous studies have shown that the MA wind and temperature are not properly resolved in numerical weather prediction (NWP) models. Therefore, high-resolution soundings of the Compact Rayleigh Autonomous Lidar (CORAL) are incorporated in the modelling. The infrasound data are processed using the progressive Multi-Channel Correlation (PMCC) algorithm.

This sensitivity study focuses on one year of collocated infrasound and lidar measurements in southern Argentina. It highlights the seasonal effects of MA uncertainties on infrasound propagation and detections in 2018.