dc.contributor.author | Berild, Martin Outzen | |
dc.contributor.author | Fuglstad, Geir-Arne | |
dc.date.accessioned | 2024-01-15T09:31:14Z | |
dc.date.available | 2024-01-15T09:31:14Z | |
dc.date.created | 2023-04-12T15:37:46Z | |
dc.date.issued | 2023 | |
dc.identifier.citation | Spatial Statistics Volume 55, June 2023, 100750 | en_US |
dc.identifier.issn | 2211-6753 | |
dc.identifier.uri | https://hdl.handle.net/11250/3111446 | |
dc.description.abstract | Isotropic covariance structures can be unreasonable for phenomena in three-dimensional spaces. In the ocean, the variability of a response may vary with depth, and ocean currents may lead to spatially varying anisotropy. We construct a class of non-stationary anisotropic Gaussian random fields (GRFs) in three dimensions through stochastic partial differential equations (SPDEs), where computations are done efficiently using Gaussian Markov random field approximations. A key novelty is the parametrization of the spatially varying anisotropy through vector fields.
In a simulation study, we find that simple stationary models obtain reasonable parameter estimates with a moderate number of observations and a single realization, whereas the most complex non-stationary anisotropic model requires dense observations and multiple realizations. Further, we construct a stationary and a non-stationary GRF prior for salinity in an ocean mass outside Trondheim, Norway, based on simulations from the complex numerical ocean model SINMOD. These GRF priors are then evaluated using in-situ measurements collected with an autonomous underwater vehicle. We find that the new model outperforms the stationary anisotropic GRF prior for real-time prediction of unobserved locations both in terms of root mean square error and continuous rank probability score. | en_US |
dc.language.iso | eng | en_US |
dc.publisher | Elsevier | en_US |
dc.rights | Navngivelse 4.0 Internasjonal | * |
dc.rights.uri | http://creativecommons.org/licenses/by/4.0/deed.no | * |
dc.title | Spatially varying anisotropy for Gaussian random fields in three-dimensional space | en_US |
dc.title.alternative | Spatially varying anisotropy for Gaussian random fields in three-dimensional space | en_US |
dc.type | Journal article | en_US |
dc.type | Peer reviewed | en_US |
dc.description.version | publishedVersion | en_US |
dc.source.volume | 55 | en_US |
dc.source.journal | Spatial Statistics | en_US |
dc.identifier.doi | 10.1016/j.spasta.2023.100750 | |
dc.identifier.cristin | 2140359 | |
dc.relation.project | Norges forskningsråd: 305445 | en_US |
cristin.ispublished | true | |
cristin.fulltext | original | |
cristin.qualitycode | 1 | |