Parallel tempering in trans-dimensional Bayesian geoacoustic inversion for high-information-content data and multi-parameter models.

Trans-dimensional (trans-D) Bayesian inversion is a powerful approach to estimate seabed geoacoustic models from ocean-acoustic data, combining quantitative model selection and uncertainty estimation. Trans-D inversion samples probabilistically over the number of seabed layers and the geoacoustic parameters for each layer, with layers added and removed in sampling, changing the dimension of the model. However, the probability of accepting dimension changes can approach zero for problems involving highly informative data or large numbers of parameters per layer. This Letter examines the use of parallel tempering, which employs a sequence of interacting Markov chains with successively relaxed likelihoods, to address these challenging cases.