The Central and Eastern European Infrasound Network (CEEIN) detects significant irregularities in microbarom arrivals between 15 and October 18, 2017. The processes driving the irregular microbarom arrivals are searched in the microbarom source region in the North Atlantic and in the stratospheric waveguide. Generation of microbaroms is simulated using ocean WAVEWATCHIII wave-action model and an updated source theory which combines the effects of both finite depth ocean and source directivity. Signal propagation in a uniform range independent atmosphere is considered. In the studied time interval, a dominant moving microbarom source occurs at the tail of the post-tropical storm Ophelia.

The storm Ophelia provides an opportunity to study the development of an intense microbarom source on the open ocean and particularly in coastal waters. Discrepancies between observations and modelling results are identified and discussed. This study shows that the state-of-the-art wave-action models are underestimated in coastal areas during storms which can pose a problem for civil security in coastal areas. The capability of the CEEIN stations to monitor microbaroms is proved. Measurement biases and uncertainties associated with the configurations of the CEEIN stations and current limitations of the processing method are discussed and improvements are suggested.