Characterization of Ambient Noise Recorded in the Norwegian Sea
Abstract
This thesis characterizes mid-frequency (19 kHz) ambient noise collected with an acoustic array over a two-week period in the Norwegian Sea. Noise characterization is an important prerequisite for many applications, including department of defense applications, environmental and biological research. The basic methodology consists of calibrating single hydrophone data for power spectral density (PSD) in dB re (Mu)1Pa^2/Hz. We present omni-directional ambient noise statistics over time, including percentiles and standard deviation for a variety of temporal averages, ranging from 1 to 60 min. These results compare well to historic observations. Wenz suggests spectrum level of approximately 45 (dB re 1 (Mu)Pa^2/Hz) for a sea state 2, while the result from this thesis finds spectrum level of approximately 43 (dB re 1 (Mu)Pa2/Hz). Furthermore, results are compared to a wind-based ambient noise model. The model prediction tracks with the data presented relatively well with a slight offset. The slight offset is further explored and gives details of the prevailing sea state. As predicted, the model slightly overestimates the PSD level of the data at sea state 2. This misfit is explored for different sea states and wind speeds.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 2023
- Accession Number
- AD1212918
Entities
People
- Christopher M. Griggs
Organizations
- Naval Postgraduate School