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| Author: | Milton Garces |
| Institution: | University of Hawaii, Manoa |
| Email: | milton@isla.hawaii.edu |
| Authors: | Milton Garces, Claus Hetzer and Mark Willis |
Abstract Title:
"Source modeling of microbarom signals generated by nonlinear ocean surface wave interactions" |
Abstract:
Severe weather in the ocean generates infrasonic signals in the 0.1-0.5 Hz frequency band that can propagate for thousands of kilometers. The source generation mechanism for these microbarom signals is attributed to the nonlinear interaction of surface ocean waves, which are predicted to radiate acoustically only if the swells are almost opposite in direction and of a near identical frequency. We study the statistics of microbarom signals detected at International Monitoring System station I59US, Hawaii, to identify features that may be used to assess array performance in the microbarom range. For selected storm systems, we use the global ocean wave estimates produced by NOAA’s World Watch 3 (WW3) to estimate the spatial and temporal distribution of the acoustic source spectra induced by nonlinear ocean wave interactions. We then use empirical amplitude relationships in conjunction with the Naval Research Laboratory (NRL) ground-to-space (G2S) atmospheric specifications to produce the predicted microbarom signal levels and peak frequencies. Results will be presented with a view toward applications in storm and sea-state evolution and how these affect infrasonic detection thresholds in the microbarom frequency band. |
| Keywords: | Microbaroms nonlinear interaction surface ocean waves storms NOAA source spectra G2S WW3 detection |
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