Long range intensity fluctuations on the Chukchi continental shelf measured during the year-long Canada Basin Acoustic Propagation Experiment 2017

Analysis of one-year-long broadband transmissions from five deep water sound sources recorded on shelf during the Canada Basin Acoustic Propagation shows strong azimuthal variability. Broadband chirp signals (140–325 Hz) transmitted every 4 h were received on spatially distributed receiver arrays on the Chukchi shelf from October 2016 through 2017. Here, we present spatial, temporal, and azimuthal correlations by four receiver arrays with source-receiver distances ranging from 228.6 to 524.4 km in a cross-the-shelf orientation. Temporal fluctuations in received field are related to water column variability for each source-receiver pair. Received signals from the same source to each receiver on the shelf, separated from 15.8 to 49.63 km in “along-the-shelf” direction show large intensity fluctuation. This is related to the turbulence that signals have experienced in their path. Temporal and spatial variations of temperature profiles were measured on the shelf, however, from deep water sources to the shelf break region, there is little information. Analysis are conducted for three time zones, from fully frozen seas, transition from full ice, and ice-free conditions. The parabolic equation model is used to report the propagation of field for the ice-free condition. Limitations of the acoustic modeling due to spatially under-sampled input environmental parameters are discussed. [Work supported by ONR-322 OA.]Analysis of one-year-long broadband transmissions from five deep water sound sources recorded on shelf during the Canada Basin Acoustic Propagation shows strong azimuthal variability. Broadband chirp signals (140–325 Hz) transmitted every 4 h were received on spatially distributed receiver arrays on the Chukchi shelf from October 2016 through 2017. Here, we present spatial, temporal, and azimuthal correlations by four receiver arrays with source-receiver distances ranging from 228.6 to 524.4 km in a cross-the-shelf orientation. Temporal fluctuations in received field are related to water column variability for each source-receiver pair. Received signals from the same source to each receiver on the shelf, separated from 15.8 to 49.63 km in “along-the-shelf” direction show large intensity fluctuation. This is related to the turbulence that signals have experienced in their path. Temporal and spatial variations of temperature profiles were measured on the shelf, however, from deep water sources to the shelf ...