Recent advances in ocean circulation modelling and applications for oil spill preparedness K.POPOVA Marine System Modelling
National Oceanography Centre Integrated ocean research and technology development from the coast to the deep ocean.
National Capability in High Resolution Global Ocean Modelling • Global high resolution ocean model (NEMO) • The model is run on a £43 million supercomputer, ARCHER (Academic Research Computing High End Resource) capable of more than one million billion calculations a second • The model costs the Natural Environment Research Council (NERC) more than ~£1 m/year in personnel costs alone to develop, run and analyse the model and its outputs.
NEMO ocean circulation model at 1/12 resolution
Marine System Modelling group World leading expertise in • High resolution global modelling and climate change • Impact of ocean circulation and climate change on living marine resources • Impact of Arctic Ice retreat
Importance of resolution ~7km ~20km ~100km
How is the circulation model verified? Hundreds of modelling research projects looking at specific areas and features of interest and comparing with in-situ, satellite-derived and ARGO data More than 30 years of experience in global modelling scientific community in recognising the processes, regional and global features Observational programs dedicated to the ocean circulation with model verification components
In-situ measurements (moorings) Deploying RAPID array (2004)
In-situ measurements (cruises) Water Mass Structure: Salinity on East Section Shipboard ADCP Currents at 50m Depth Indonesian Throughflow Tropical Surface Water Water (ITW) (TSW) Arabian Sea High Subtropical Salinity Surface Water Water (STSW) Antarctic Intermediate Water (AAIW) Mascarene Plateau in the Indian Ocean
ARGO floats
Satellite-derived velocities Model Satellite-derived
Satellite-derived velocities 1 o 1/4 o 1/12 o AVISO Agulhas retroflection
Rubber Ducks and ocean circulation
Rubber Ducks and ocean circulation
Oil spills and pollution modelling: preparedness vs response Response modelling Risk assessment modelling • Operational (based on real- time forward prediction) • Deals with a specific situation as it develops • Considers short time scales relevant to the clean-up operation • Emergency
Oil spills and pollution modelling: preparedness vs response Response modelling Risk assessment modelling • • Operational (based on real- Non-operational (based on time forward prediction) modelling of the recent past) • • Deals with a specific situation Considers full range of possible as it develops scenarios • • Considers short time scales Aims at longer timescales and relevant to the clean-up wider spatial scales operation • Deals with the worst case • Emergency scenario
Use of circulation models by the industry The model most commonly used: SINTEF oil spill model embedded into Norwegian MO Operational model (HYCOM) Why? Circulation at daily resolution for two years are readily available free of charge (1990 and 91) Concern: use of a single circulation model • There is no silver bullet for ocean circulation, • No single model will work universally well across all areas • HYCOM does not perform well at high latitudes Can leading UK model be of use?
NOC-OSRL collaborative project • For the probabilistic analysis of the oil spill impact OSRL needs to run OSCAR embedded into multiple time periods of the circulation fields (e.g. releases starting in different seasons and/or years). • The process is computationally expensive • Can we design a similar (and computationally much cheaper) experiments which will show details of the ocean circulation relevant to the potential transport of oil by ocean currents?
Probabilistic analysis Questions we would like to answer: • Is summer spill the same as winter spill? • Is there substantial interannual variability? • Are there anomalous years? Months? • How does the circulation changes with depth?
Case study areas of high interest and/or activity for the petroleum industry (in collaboration with Oil Spill Response Ltd)
Importance of ocean circulation in oil spill risk assessment: Brazil case study
Circulation footprint January 1995 • A single short term release at a given date, at a given depth • How far would a spill go to over a given time period? Time (months)
Circulation footprint January 1995 June 1995 Near-surface Near-surface Time (months)
Circulation footprint January 1995 January 1995 500m Near-surface Time (months)
Importance of ocean circulation in oil spill risk assessment: Brazil case study 500m 500m TUPI CAMPOS 0m 0m
Variability in the footprint 50m 500m Total Shape area difference 900m
Probabilistic footprint A relative likelihood to find spilled oil in a given location
Probabilistic footprint Is Campos different from Tupi near surface?
Probabilistic footprint Does circulation change direction with depth? 5m Campos 500m
Probabilistic circulation footprint 0m 500m 2000m Submitted to Journal of Marine Systems
Case study areas of high interest and/or activity for the petroleum industry (in collaboration with Oil Spill Response Ltd)
Impact of Arctic ice retreat • Arctic shipping routes • Oil spills in ice-covered environment • Living marine resources (ocean acidification)
Loss of Arctic sea-ice under RCP 8.5
Arctic navigability 2010-2019 2020-2039 Sea ice concentration and thickness during the navigation period (June-Oct) and time of crossing for various classes of vessels Aksenov et al, MP, 2016
Oil spills in ice-covered Arctic: Basic facts • Spilled oil can potentially be trapped in or under the ice and drift with the ice cover • Weathering of oil in freezing temperatures and in the presence of ice occurs more slowly • Oil spills encapsulated in ice during the freeze-up period will be returned to the surface during the spring thaw
Impact of Arctic cascading on lagrangian pathways • Ocean velocity is 3 dimensional • Although its vertical component is very small, its effect is pronounced in the Arctic
Oil in drifting ice
Online NEMO output Information on past, present-day and future ocean and sea ice (1948-now-2099): • 3-D currents, ocean temperature, salinity, turbulence, icebergs spread & sizes • Sea ice thickness, ice types, concentration, floe sizes, ice compressive/shear pressure Available online from June 2016
Collaborating with NOC NERC Knowledge Exchange Fellowships Part time Knowledge Exchange Fellowships are available in any area of policy, business or third sector with the aim of boosting the impact of any type of NERC funded science NERC Knowledge Exchange and Impact projects Collaborative projects between industry and NERC scientists demonstrating impact of NERC funded science on business performance
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