Local likelihood estimation for covariance functions with spatially-varying parameters: the convoSPAT package for R

In spite of the interest in and appeal of convolution-based approaches for nonstationary spatial modeling, off-the-shelf software for model fitting does not as of yet exist. Convolution-based models are highly flexible yet notoriously difficult to fit, even with relatively small data sets. The general lack of pre-packaged options for model fitting makes it difficult to compare new methodology in nonstationary modeling with other existing methods, and as a result most new models are simply compared to stationary models. Using a convolution-based approach, we present a new nonstationary covariance function for spatial Gaussian process models that allows for efficient computing in two ways: first, by representing the spatially-varying parameters via a discrete mixture or "mixture component" model, and second, by estimating the mixture component parameters through a local likelihood approach. In order to make computation for a convolution-based nonstationary spatial model readily available, this paper also presents and describes the convoSPAT package for R. The nonstationary model is fit to both a synthetic data set and a real data application involving annual precipitation to demonstrate the capabilities of the package

The Open Navigation Surface Project

Many hydrographic and oceanographic agencies have moved or are moving towards gridded bathymetric products. However, there is no accepted format to allow these grids to be exchanged while maintaining data and metadata integrity. This paper describes the Open Navigation Surface (ONS) Project, which aims to fill this gap. The ONS Project is an open-source software project designed to provide a freely available, portable source-code library to encapsulate gridded bathymetric surfaces with associated uncertainty values. The data file format is called a Bathymetric Attributed Grid (BAG). The BAG is developed and maintained by the ONS Working Group (ONSWG), and the source code is available via the ONS websit

The Open Navigation Surface Project

Many hydrographic and oceanographic agencies have moved or are moving towards gridded bathymetric products. However, there is no accepted format to allow these grids to be exchanged while maintaining data and metadata integrity. This paper describes the Open Navigation Surface (ONS) Project, which aims to fill this gap. The ONS Project is an open-source software project designed to provide a freely available, portable source-code library to encapsulate gridded bathymetric surfaces with associated uncertainty values. The data file format is called a Bathymetric Attributed Grid (BAG). The BAG is developed and maintained by the ONS Working Group (ONSWG), and the source code is available via the ONS website.Muchas agencies hidrogrâficas y oceanogrâficas se han orientado o se estân orientando hacia los productos batimétricos cuadriculados. Sin embargo, no existe un formato aceptado para que estas cuadricuias sean intercambiadas manteniendo la integridad de los datos y los meta datos. Este articulo describe el Proyecto « Superficie de Navegaciôn Abierta » (ONS) cuyo objeto es cubrir este vacio. El proyecto ONS es un proyecto de software de fuente abierta disehado para proveer una biblioteca portâtil de côdigo fuente de libre disponibilidad para encapsular superficies batimétricas cuadriculadas con sus valores de incertidumbre asociados. El formato de archivo de datos es llamado Cuadricula Batimétrica Tributada (BAG). El BAG es desarrollado y mantenido por el Grupo de Trabajo ONS (ONSWG), y el côdigo fuente es disponible a través de sitio web de ONS.De nombreuses agences hydrographiques et océanographiques se sont orientées ou s ’orientent actuellement vers les produits bathymétriques quadrillés. Toutefois, il n'existe pas de format accepté qui permette à ces quadrillages d'être échangés tout en conservant l’intégrité des données et des métadonnées. Le présent article décrit le projet ONS (Open Navigation Surface) qui vise à combler cette lacune. Le projet ONS est un projet de logiciel libre conçu pour fournir une bibliothèque portable de code source à libre disponibilité devant encapsuler des surfaces bathymétriques maillées avec des valeurs d'incertitude associées. Le format du fichier des données est appelé Carroyage bathymétrique attribué (BAG). Le BAG est développé est tenu à jour par le groupe de travail ONS et le code source est disponible sur le site Web ONS

Thermal structure of a gas-permeable lava dome and timescale separation in its response to perturbation

The thermal boundary layer at the surface of a volcanic lava dome is investigated through a continuum model of the thermodynamic advection diffusion processes resulting from magmatic gas flow through the dome matrix. The magmatic gas mass flux, porosity and permeability of the rock are identified as key parameters. New, theoretical, nonlinear steady-state thermal profiles are reported which give a realistic surface temperature of 210 degC for a region of lava dome surface through which a gas flux of 3.5 x 10-3 kg s-1 m-2 passes. This contrasts favourably with earlier purely diffusive thermal models, which cool too quickly. Results are presented for time-dependent perturbations of the steady states as a response to: changes in surface pressure, a sudden rockfall from the lava dome surface, and a change in the magmatic gas mass flux at depth. Together with a generalized analysis using the method of multiple scales, this identifies two characteristic time scales associated with the thermal evolution of a dome carapace: a short time scale of several minutes, over which the magmatic gas mass flux, density, and pressure change to a new quasi-steady-state, and a longer time scale of several days, over which the thermal profile changes to a new equilibrium distribution. Over the longer time scale the dynamic properties of the dome continue to evolve, but only in slavish response to the ongoing temperature evolution. In the light of this time scale separation, the use of surface temperature measurements to infer changes in the magmatic gas flux for use in volcanic hazard prediction is discussed

Anticipating and Adapting to the Future Impacts of Climate Change on the Health, Security and Welfare of Low Elevation Coastal Zone (LECZ) Communities in Southeastern USA

Low elevation coastal zones (LECZ) are extensive throughout the southeastern United States. LECZ communities are threatened by inundation from sea level rise, storm surge, wetland degradation, land subsidence, and hydrological flooding. Communication among scientists, stakeholders, policy makers and minority and poor residents must improve. We must predict processes spanning the ecological, physical, social, and health sciences. Communities need to address linkages of (1) human and socioeconomic vulnerabilities; (2) public health and safety; (3) economic concerns; (4) land loss; (5) wetland threats; and (6) coastal inundation. Essential capabilities must include a network to assemble and distribute data and model code to assess risk and its causes, support adaptive management, and improve the resiliency of communities. Better communication of information and understanding among residents and officials is essential. Here we review recent background literature on these matters and offer recommendations for integrating natural and social sciences. We advocate for a cyber-network of scientists, modelers, engineers, educators, and stakeholders from academia, federal state and local agencies, non-governmental organizations, residents, and the private sector. Our vision is to enhance future resilience of LECZ communities by offering approaches to mitigate hazards to human health, safety and welfare and reduce impacts to coastal residents and industries