Showing papers on "Gnome published in 2018"

Simulation of the 2003 Foss Barge - Point Wells Oil Spill: A Comparison between BLOSOM and GNOME Oil Spill Models

Abstract: The Department of Energy’s (DOE’s) National Energy Technology Laboratory’s (NETL’s) Blowout and Spill Occurrence Model (BLOSOM), and the National Oceanic and Atmospheric Administration’s (NOAA’s) General NOAA Operational Modeling Environment (GNOME) are compared. Increasingly complex simulations are used to assess similarities and differences between the two models’ components. The simulations presented here are forced by ocean currents from a Finite Volume Community Ocean Model (FVCOM) implementation that has excellent skill in representing tidal motion, and with observed wind data that compensates for a coarse vertical ocean model resolution. The comprehensive comparison between GNOME and BLOSOM presented here, should aid modelers in interpreting their results. Beyond many similarities, aspects where both models are distinct are highlighted. Some suggestions for improvement are included, e.g., the inclusion of temporal interpolation of the forcing fields (BLOSOM) or the inclusion of a deflection angle option when parameterizing wind-driven processes (GNOME). Overall, GNOME and BLOSOM perform similarly, and are found to be complementary oil spill models. This paper also sheds light on what drove the historical Point Wells spill, and serves the additional purpose of being a learning resource for those interested in oil spill modeling. The increasingly complex approach used for the comparison is also used, in parallel, to illustrate the approach an oil spill modeler would typically follow when trying to hindcast or forecast an oil spill, including detailed technical information on basic aspects, like choosing a computational time step. We discuss our successful hindcast of the 2003 Point Wells oil spill that, to our knowledge, had remained unexplained. The oil spill models’ solutions are compared to the historical Point Wells’ oil trajectory, in time and space, as determined from overflight information. Our hindcast broadly replicates the correct locations at the correct times, using accurate tide and wind forcing. While the choice of wind coefficient we use is unconventional, a simplified analytic model supported by observations, suggests that it is justified under this study’s circumstances. We highlight some of the key oceanographic findings as they may relate to other oil spills, and to the regional oceanography of the Salish Sea, including recommendations for future studies.

Numerical simulation of oil spills based on the GNOME and ADIOS

Abstract: The Exxon Valdez oil spill emergency has shown that simulation of oil spills trajectory is the main action in planning response measures. Modeling the trajectory of the oil slick allows predicting in advance the direction of the motion of the stain, the time it will take to reach the shore and assess the possible environmental consequences for the contaminated coastal zone. In this paper, the Exxon Valdez oil spill trajectory was analyzed using two different models, the GNOME model and the HAZAT trajectory model. Conclusions are drawn about the reasons for the differences in the results provided by the two models. The accuracy of the simulation is strongly related to the input of geographic and meteorological data. In addition, ADIOS software was used to predict the weathering process of the modeled emergency event. It was found that the main factors influencing the change in the physical and chemical characteristics of oil dispersed in the water body are the wind speed and direction, water temperature and wave height.

Characterization of the Global Network of Optical Magnetometers to search for Exotic Physics (GNOME).

Abstract: The Global Network of Optical Magnetometers to search for Exotic physics (GNOME) is a network of geographically separated, time-synchronized, optically pumped atomic magnetometers that is being used to search for correlated transient signals heralding exotic physics. The GNOME is sensitive to nuclear- and electron-spin couplings to exotic fields from astrophysical sources such as compact dark-matter objects (for example, axion stars and domain walls). Properties of the GNOME sensors such as sensitivity, bandwidth, and noise characteristics are studied in the present work, and features of the network's operation (e.g., data acquisition, format, storage, and diagnostics) are described. Characterization of the GNOME is a key prerequisite to searches for and identification of exotic physics signatures.

Application of Free Software (GNOME) for Simulation of Oil Spills Trajectories in a Sector of Magdalena River (Colombia)

Abstract: According to the National Environmental Licenses Authority –ANLA, between 2004 and 2017, there were around 6.300 oil spills in Colombia, 40 % of which affected freshwater bodies. However, at the national level, the use of spill behavior prediction tools is not very extensive, due to the high costs of commercial software. Therefore, the main objective of this paper was to use the free software GNOME (General NOAA Operational Modeling Environment) in a sector of the Magdalena river (most important Colombian river). A collection of 54 instantaneous spills scenarios were simulated. Where a variation in the hydrocarbons type, volume spilled, wind direction and the time elapsed after effusion were considered. The comparison of the spill scenario’s mass balance showed that during the first six hours regardless the wind direction most of the hydrocarbons are deposited on banks, except for gasoline. After this time, the hydrocarbons are affected by environmental conditions and are volatilized, decreasing the remaining in water surface and banks. The results obtained were consistent with the literature respect to the volume of evaporated product is greater in the lighter products. The primary fate of spilled oil coincided with the previous modeling in the same sector of the river with software for private use. In both cases, the most probable destination of the hydrocarbons were the riverbanks. Since there are no other similar studies in Colombia, there was not possible to establish a comparison of results regarding the effect of wind direction and hydrocarbon type (specifically for the study sector). In conclusion, GNOME is an open-access software which evaluates the main processes that influence the oil spill’s displacement (diffusion, evaporation, and dispersion) offering consistent results. The novelty of this paper is that it is the first application of GNOME in a Colombian river, as an alternative for increasing the use of numerical modelling tools in the design of contingency plans in the country.