There is widespread recognition that Arctic conditions can challenge marine oil spill response by limiting countermeasure effectiveness and, in extreme cases, even preventing their use. The Arctic Council's Emergency Prevention, Preparedness, and Response (EPPR) Workgroup implemented a response viability analysis to estimate how often different types of response systems could be deployed in different areas of the Arctic based on historical met ocean conditions. This approach, implemented previously in several circumpolar sub-regions, quantifies the effects of met ocean conditions on response techniques by comparing the operating limits for different response systems to a hind cast of met ocean data. Response systems include options for mechanical recovery, chemical dispersants, and in-situ burning. Met ocean conditions in the dataset used include wind, sea state, temperature, sea ice coverage, horizontal visibility, and daylight/darkness. Additional conditions are discussed qualitatively. For each response system studied, the results indicate how often use of that system may be favorable, marginal, or not recommended. Seasonal and geographic variations in the results can inform response contingency planning. Examining the met ocean condition that most frequently impacts a system can also inform needed technological improvements or modifications. EPPR convened experts to provide input to the analysis, including the initial project scoping and development of baseline systems and limits. This paper discusses the project process as well as the analytical methodology, key inputs, assumptions, and results.

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Oil spill contingency planning for a marine environment requires a thorough understanding of metocean conditions that can be expected within the planning area. Oil spill response systems have different resilience, or viability, towards the physical environment encountered at sea. Hence it is important to know the operational limitations of response systems, and how metocean factors may impact on operations. The Norwegian Coastal Administration (NCA) contracted DNV GL to perform an Oil Spill Response Viability analysis to quantify the window of opportunities for defined oil spill response systems. A Response Viability Analysis (RVA) estimates the percentage of time that metocean conditions may be favorable, marginal, or not favorable for defined oil spill response systems. A 10×10 km metocean dataset was established covering Norwegian waters, including a 10-year data series with relevant parameters; wind speed, wave height, horizontal visibility, daylight/darkness, wind chill, structural icing and sea ice concentration. NCA identified 12 relevant response systems for the analysis, and established individual operational limitations for included parameters. The limits defined the response conditions in three categories; 1) favorable conditions, 2) marginal conditions and 3) unfavorable conditions. The analysis was conducted for 3-hour time steps in each grid cell in the study area using a custom code identifying it as favorable, marginal or unfavorable for each of the response systems. The results were implemented in a web-based tool to make the large amount of data produced by the analysis easily available to the user. Key information in the tool is preprocessed maps showing monthly distribution of each response category for each response system as percentage of time. By clicking on the maps, more detailed information is available for each grid cell. This includes a histogram with monthly viability for the chosen response system. All the response systems are internally ranked by the highest viability for the chosen month, and the limiting factor (if any) is displayed automatically. Additional features in the tool include a map showing potential change of wave height due to future climate changes, based from another study. The web-tool also includes typical map-tools as well as metadata.

A near real-time environmental calculation of oil spill risk along the entire coast of Norway is developed as the EnviRisk model. Previous risk assessments utilize older decision models and repeated manual calculations that are costly as well as not accounting for the complexity of and changes in, ship traffic. Furthermore, cloud-providers have enabled enough data ingest and processing power to utilize high resolution shore and satellite based AIS data (Automated Identification System), to develop more dynamic and accurate risk calculation models than before. EnviRisk builds upon AISyRisk, an automated risk calculation model for marine traffic developed by the Norwegian Coastal Administration (NCA) and DNV GL. AISyRisk, includes a long-term data collection on probability of ship accidents and consequences for fatalities and oil spills for Norwegian waters (Norwegian Coastal Administration 2020). From AISyRisk, the probabilities for a certain oil spill (location, oil type and volume) is developed further to assess the environmental consequence in the EnviRisk model. As part of EnviRisk, extensive oil spill modelling is being performed in the cloud with the open source OpenDrift model (https://github.com/opendrift/opendrift/wiki) released by the Norwegian Meteorological Institute. This, combined with environmental sensitivity for both seabirds, marine mammals, fish and shoreline habitats, makes it feasible to quantify the environmental consequence and risk. Environmental risk is presented on a 10x10 km grid for the previous month of ship traffic and also accumulates statistics for risk over time. This paper presents the automated oil spill modelling and environmental risk calculation in EnviRisk. The method builds upon previous risk assessments for NCA for the Norwegian Coast (Braathen and Brude, 2011), for Svalbard and Jan Mayen (Braathen et. al., 2014) and for Greenland for Defence Command Denmark also in 2014 (Eikeland et. al., 2014). The approach is significantly improved particularly with respect to the oil spill modelling. Updates of AISyRisk and EnviRisk data and calculations are done monthly and the results published on a web portal administered by the Norwegian Coastal Administration where aggregated results are publicly available.