Recent advances in ocean circulation modelling and applications for - - PowerPoint PPT Presentation

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

~100km ~7km ~20km

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)

Shipboard ADCP Currents at 50m Depth

Subtropical Surface Water (STSW) Antarctic Intermediate Water (AAIW) Tropical Surface Water (TSW) Water Mass Structure: Salinity on East Section Indonesian Throughflow Water (ITW) Arabian Sea High Salinity Water

In-situ measurements (cruises)

Mascarene Plateau in the Indian Ocean

ARGO floats

Satellite-derived velocities

Model Satellite-derived

1o 1/4o 1/12o AVISO

Satellite-derived velocities

Agulhas retroflection

Rubber Ducks and ocean circulation

Rubber Ducks and ocean circulation

Oil spills and pollution modelling: preparedness vs response

Response 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

• peration
• Emergency

Risk assessment modelling

Oil spills and pollution modelling: preparedness vs response

Response 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

• peration
• Emergency

Risk assessment modelling

• Non-operational (based on

modelling of the recent past)

• Considers full range of possible

scenarios

• Aims at longer timescales and

wider spatial scales

• Deals with the worst case

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

• A single short term release

at a given date, at a given depth

• How far would a spill go to
• ver a given time period?

Time (months) January 1995

Circulation footprint

Time (months) January 1995 Near-surface June 1995 Near-surface

Circulation footprint

Time (months) January 1995 Near-surface January 1995 500m

Importance of ocean circulation in oil spill risk assessment: Brazil case study

TUPI CAMPOS 500m 0m 0m 500m

Variability in the footprint

Total area Shape difference 50m 900m 500m

Probabilistic footprint

A relative likelihood to find spilled oil in a given location

Probabilistic footprint

Is Campos different from Tupi near surface?

Probabilistic footprint

5m 500m Campos Does circulation change direction with depth?

0m 500m 2000m

Probabilistic circulation footprint

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

• f 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