Sea ice modelling, forecasting, and validation activities at

Alfred Wegener Institute (AWI), Bremerhaven, Germany

Christian Haas

• Modelling• Thickness profiling• SAR remote sensing

• Operating stand-alone & coupled ice-

ocean dynamic/thermodynamic models

after Hibler & Lemke, Semtner• Viscous-plastic & elastic viscous plastic

rheologies• Arctic and Antarctic• Modified and improved by Fischer,

Harder, Kreyscher, Hillmer, Lieser• Focus on climate system studies• New: Finite element (FE) modelling

[1/km][1/km]

Ridge frequency

Variability of Arctic sea-ice volume

1951-1999

Spatial thickness and drift trends

1951-19991951-1999

Temperature anomalies in the Arctic Ocean

AWI-NAOSIM

Temperature flux through Fram Strait

1997 Temperature

Anomaly(450 m depth)

FE ModelMotivationMotivation• Accurate Mesh Refinement and Adaptive

Meshes• Variational Formulation for Complex Rheologies

SSM/I observations Sea ice model data 8.3.98 8.3.98

Assimilation (OI)

Model run (7 days)

SSM/I observations Sea ice model data15.3.98 15.3.98

Assimilation (OI)

Model run (5 days)

SSM/I observations Sea ice model data20.3.98 20.3.98

Comparison

Assimilation Scheme

SSM/I (observed) Model (stand-alone) Model (assimilation)

Result of Assimilation

EM thickness profiles

SIMS:Sea Ice Monitoring System

Helicopter-borne EM profiling

EM Bird

Typical EM bird thickness profile and distribution

Ice thickness variability in the Transpolar Drift:1991, 1996, 1998 & 2001

Ice Ridging Information for Decision Making in Shipping

600

500

400

300

200

100

0

Num

ber

of m

easu

rem

ents

86420

Ice thickness, m

030315Mode = 1.3 mMean = 1.55 +- 1.12 m

3000

2000

1000

0

Num

ber

of m

easu

rem

ents

86420

Ice thickness, m

030316Mode = 0.2 mMean = 0.32 +- 0.38 m

500

400

300

200

100

0

Num

ber

of m

easu

rem

ents

86420

Ice thickness, m

030312Mode = 1.9 mMean = 2.49 +- 1.49 m

6

5

4

3

2

1

0

4442403836x10

3

500

400

300

200

100

0

Num

ber

of m

easu

rem

ents

86420

Ice thickness, m

030315_3Modes = 0.2 m, 0.8 m, 1.9 mMean = 1.42 +- 1.03 m

Sea Ice Thickness Observation System

Polarstern

Integration of SAR imagery for algorithm development and extrapolation to larger ice

regimes

Sea Ice Thickness Observation System