Mid-frequency attenuation estimates from deep-water experiments using eigenrays

Abstract

A collection of deep-water experiments were recently performed using a short vertical array cut for 7.5 kHz and a source transmitting tonals as well as chirps. Eigenray arrivals out to the first convergence zone were identified through matching the processed data to ray-tracing models, using environmental parameters measured during the experiments. The ray path and transmission loss information were used to produce an ocean-average attenuation result, and compared to decades-old attenuation models. Attempts were made at producing a layered estimate of attenuation using the experimental-simulation ray-matching — a technique previously proposed for inverting for ocean acidity. We present our ocean-average mid-frequency attenuation estimates, and our initial results for a layered attenuation inversion.