Numerical modeling of oil spills in the Gulf of Morrosquillo, Colombian Caribbean

Abstract

This study encompasses the analysis of oil spills occurred in the Gulf of Morrosquillo during the loading procedures of oil tankers in the Coveñas maritime Terminal, by means of numerical simulation experiments of the trajectories and weathering processes of oil spilled, which occurred under specific wind, waves, and ocean currents conditions. A three-dimensional (3D) modelling system, OpenOil, which is part of the open-source OpenDrift trajectory framework was used to simulate two contingencies occurred in July and August 2014. During each event, different volumes of Vasconia crude oil spilled on the sea surface were simulated. The resulting slicks were subject to wind drift, Stokes drift from wave forcing, and ocean currents transporting the oil spilled towards the coast. Oil weathering effects (evaporation, emulsification, and biodegradation) are included in the analysis. To calculate weathering of the oil, OpenOil interfaces with the latest version of the open source ADIOS oil library. It should be noted that meteorological and ocean conditions contribute to the oil pathways that in both periods forced the oil slick towards the central coast of the Gulf. The wind speed is an important factor contributing to the rapid evaporation rates of the oil spilled in the warm waters of the Caribbean Sea; hence, allowing a gradual increase of the water fraction, which could lead to the formation of tar balls found in the affected coasts in the areas simulated by the model. The implementation of OpenOil to predict the oil fate and weathering processes in the Colombian basin prove to be a valuable tool that should be used in this maritime terminal to improve planning and preparedness in case of an oil spill. The simulations could be enhanced with higher resolution databases.

Modes of Operation and Forcing in Oil Spill Modeling: State-of-Art, Deficiencies and Challenges

“…However, the model allows the coupling with the coarser resolution forecasts from CMEMS (Copernicus Marine Environmental Service), FVCOM, SHYFEM, CYCOFOS, HYCOM, Norshelf for hydrodynamics and ocean state, and NOAA, ECMWF, and SKIRON wind fields with netCDF and many different files format. The OpenOil has been applied in several cases worldwide, such as the Norwegian Sea [23], the Gulf of Mexico and the Cuban coast [41][42][43][44], the Thracian Sea [45], and the Caribbean Sea [46].…”

“…Further details on model description and verification can be found in the works of Ehard et al [89], Haiden et al [90], and Hersbach et al [91]. ERA5 has been used as wind boundary forcing in various oil-spill scenarios, as in Zhang et al [78], Abdallah and Chantsev [64,66], Davis Morales et al [46], and Liu et al [92]. In parallel, in the case of simulating retrospective oil spills, the ERA-Interim dataset could be used [93]; this is a global reanalysis data product covering the data-rich period since 1979.…”

“…The global ocean output files have a horizontal resolution of 1/12 • (~9 km) and a regular longitude/latitude equirectangular projection. This dataset has been widely applied in oil-spill simulations, like in the studies of Devis Morales et al [46], Sepp Neves et al [48], and Siqueira et al [52]. Moreover, CMEMS provides the dataset Mediterranean Sea Physics Analysis and Forecast (MEDSEA_ANALYSISFORECAST_PHY_006_013) [119] which is being produced from a coupled hydrodynamic-wave model, implemented over the entire Mediterranean Basin.…”

“…Focusing on the OpenOil model, of the seven studies examined, the high-resolution HYCOM-GoM 1/50 • model was used in four cases [41][42][43][44], and the HYCOM-FKEYS, with a 1/100 • resolution, in two test cases [41,43]. In addition, the model was coupled with the CMEMS data products, either the Global 1/12C data product [46], or the Mediterranean, with a 1/24 • resolution [45]. Moreover, the NorShelf model, with a 2.4 km spatial resolution, covering the hydrodynamics of the Norwegian Sea, was also used by Röhrs et al [23].…”

“…In addition, in six studies, wave data were integrated through the ECMWF and the WAM model outputs, running with a 0.125 • horizontal resolution [23,[41][42][43][44]. In two case studies, wave data were obtained from the forecasting CMEMS products, with the WAVERYS model at a 1/5 • resolution [46] and the WAM Cycle 6 model at a 1/24 • resolution [45]. Based on the above, we may conclude that a high-resolution wave model has never been used, in conjunction with high-resolution hydrodynamic and meteorological models in the operational oil-spill modeling works of the latest years.…”