EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

High resolution modelling of the decreasing Arctic sea ice

Kristine S. Madsen, T.A.S. Rasmussen, J. Blüthgen and M.H. RibergaardPolar Oceanography, Danish Meteorological Institute

Sea ice volume, 1013 m3 Oil drift 17 days after initial spill

EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

Overview

Model introduction

Sea ice changes– Extend– Volume– Ocean surface temperature

Oil drift modelling– Surface spill– Deep spill– Importance of sea ice

EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

HYCOM/CICE ocean and sea ice model

• North Atlantic and Arctic oceans

• ~10 km horizontal resolution

• Sea ice: dynamic and thermodynamic

• Ocean: hydrodynamic, 29 vertical levels (hybrid)

• ERA Interim atm. forcing, 2000–2009

• Assimilate sea ice concentration and SST from satellite once a day, nudge towards climatological SSS

EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

The CICE model

• Hibler-type elastic-viscous-plastic ice model

• Each grid cell has 5 ice thickness categories with 4 vertical layers for each, plus surface snow

• Horizontal resolution and time step same as ocean model (~10 km, 5 minutes)

EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

Sea ice concentration

Sea ice area (concentration ≥ 30%), 1012 m2

Model Observations

Source: ocean.dmi.dk/arctic

EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

Sea ice concentration

2001 2007

Units: %

EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

Sea ice concentrations – September 1O

bse

rva

tions

Mo

de

l

Source (observations):U. of Illinois

The Cryosphere Today

Units: %

EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

Sea ice thickness – September 1

2001 2007

Units: m

EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

Sea ice volume

Units: 1013 m3

Model

EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

Ocean surface layer temperatureAverage for all ocean points north of 80°N, units °C

EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

Ocean surface layer temperatureAverage for ocean points w. at least 30% ice, north of 80°N, units °C

EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

Summary – sea ice

• The model reproduces concentration (within 10%) and timing of min and max sea ice concentration, but builds up ice too fast in the fall.

• The interannual variability is well represented.• Sea ice volume shows continuous build-up from October

to May and strong decrease in June.• 2007 shows large volume decrease and export along

Greenland’s east coast. 2008 and 2009 has lower ice volume than 2007.

• Summer polar ocean surface layer temperature is increased in summer 2007, also underneath the sea ice.

EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

Oil drift modeling

Existing hydrocarbon exploration & exploitation licences

Applications for new licences 2012/13

EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

DMI oil drift module

• Purposes: oil combating, “find the sinner”, drifting vessel, man overboard

• Particle model• Passive advection with ocean current• … and additional surface wind drift (3%)• Wind speed is scaled inverse linear with sea ice concentration.• Future work: Ocean speed is scaled inverse linear with sea ice

concentration towards ice velocity.• Buoyant rising (or sinking)• Downward mixing by wind waves (scaled by wind speed + random

distribution)• Turbulent spreading (random walk scaled by current speed)• Oil weathering• 8 pre-defined oil-types - based on fractions of 8 hydrocarbons• Instantaneous or continuous oil spill at any depth• Runs operationally, 15 minutes response 24-7

http://www.itopf.com

EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

Example of oil driftImaginary surface spill on

August 1-10 2003 south-east of Greenland

2 deg ~200 km

EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

Oil drift in sea ice affected areas

• Wind drag limited (already included in model)• Oil will partly drift with the ice• Oil will be trapped in pockets under the ice or freeze into

the ice – reducing weathering

EG

U 2

01

2,

Kris

tine

S.

Ma

dse

n,

kma

@d

mi.d

k

Thank you!

Sea ice volume, 1013 m3 Oil drift 17 days after initial spill