quantas - off numerical simulations of dense bottom currents in the western baltic sea:...
TRANSCRIPT
QuantAS - Off
Numerical simulations of dense bottom currents in the Western Baltic Sea: Quantification of natural,
structure-induced and numerical mixing
Funded by:
Hannes Rennau
QuantAS - Off
Model area
QuantAS - Off
Model area
Hot spot of water mass transformation
QuantAS - Off
Model area
Hot spot of water mass transformation
Drodgen Sill (~8m)
Darss Sill (~20m)
QuantAS - Off
Main pathwaysOf dense bottom
currents
QuantAS - Off
Main pathwaysOf dense bottom
currents
QuantAS - Off
Main pathwaysOf dense bottom
currents
QuantAS - Off
Main pathwaysOf dense bottom
currents
QuantAS - Off
Main pathwaysOf dense bottom
currents
QuantAS - Off
Numerical Model
- typical ocean-circulation model GETM with state of the art turbulence model GOTM (code developers for both models at IOW)
Parallel execution on IOW Linux Cluster
QuantAS - Off
Simulation of bottom salinity over nine months
QuantAS - Off
Darss Sill Tracer vs. Drodgen Sill Tracer
Tracer release positions
QuantAS - Off
Darss Sill Tracer vs. Drodgen Sill Tracer
Tracer release positions
QuantAS - Off
Darss Sill Tracer vs. Drodgen Sill Tracer
Tracer release positions
QuantAS - Off
Darss Sill Tracer vs. Drodgen Sill Tracer
Tracer release positions
QuantAS - Off
Model Validation
MARNET Arkona Station
Burchard, H., F. Janssen, K. Bolding, L. Umlauf, and H. Rennau, Model simulations of dense bottom currents in the Western Baltic Sea, Cont. Shelf Res., 29, 205-220, 2009.
x
QuantAS - Off
Natural mixing in the numerical model
Significantly increased natural mixing:
in channels (Kriegers Flak, Bornholm Channel, …)
in the area of shallow sills (Drodgen Sill, Darss Sill, …)
Burchard, H., F. Janssen, K. Bolding, L. Umlauf, and H. Rennau, Model simulations of dense bottom currents in the Western Baltic Sea, Cont. Shelf Res., 29, 205-220, 2009.
QuantAS - Off
Physical mixing Numerical mixing
found method to analyse numerical mixing
Rennau, H., and H. Burchard, Quantitative analysis of numerically induced mixing in a coastal model application, Ocean Dynamics, submitted December 2008. Burchard, H., and H. Rennau, Comparative quantification of physically and numerically induced mixing in ocean models, Ocean Modelling, 20, 293-311, 2008.
QuantAS - Off
• Fundamental knowledge about propagation of dense bottom currents in the western Baltic Sea
• Model derived amount of physically induced mixing without offshore foundations
Conclusions
QuantAS - Off
• Fundamental knowledge about propagation of dense bottom currents in the western Baltic Sea
• Model derived amount of physically induced mixing without offshore foundations
Conclusions
• numerically induced mixing and physical mixing have same orders of magnitude but different horizontal distribution
• enhanced numerical mixing –> less physical mixing
• numerical techniques: adaptive vertical coordinates,…
QuantAS - Off
Impact of bridge piles
QuantAS - Off
Impact of bridge piles
Lass et al. (2008)
distance from pile / m
QuantAS - Off
Impact of bridge piles - modeling
QuantAS - Off
Impact of bridge piles - modelingH.U. Lass et al. (2008)
28
24
20
16
2000 1000 PILE 1000 2000distance from pile / m
distance from pile / m
QuantAS - Off
GETM 2D Slice Model
QuantAS - Off
Additional mixing due to Offshore windpark foundations
Local model at University of Hannover
Regional model at IOW
Parameterisaton?
QuantAS - Off
'Worst Case Study' with Offshore Windpark
QuantAS - Off
Influence of Offshore wind park: 10. April, 2004
With windpark without windpark
QuantAS - Off
windpark
„Worst Case“ Study – Simulation with Offshore WindparkSnapshot:
bottom salinity (without windpark) – bottom salinity (with windpark)
QuantAS - Off
windpark
„Worst Case“ Study – Simulation with Offshore WindparkSnapshot:
bottom salinity (without windpark) – bottom salinity (with windpark)
+0.5
QuantAS - Off
windpark
„Worst Case“ Study – Simulation with Offshore WindparkSnapshot:
bottom salinity (without windpark) – bottom salinity (with windpark)
+0.5
-0.2
QuantAS - Off
• - expected low additional mixing due to Offshore• Windpark foundations (needs further calibration • in parameterisation and longer time series)
• - strength of additional mixing mainly dependent on:• (1) where to be build • (2) windfarm distribution (how many, …)
Main conclusions
QuantAS - Off
Main Focus for last year:
- Final results concerning additional mixing of offshore windpark foundations in the Western Baltic Sea (publication in preparation)
QuantAS - Off
Main Focus for last year:
- Final results concerning additional mixing of offshore windpark foundations in the Western Baltic Sea (publication in preparation)
- Model nesting: 3D structure development of dense bottom currents in channels (Kriegers Flak North and Bornholm Channel) (publication in preparation)
QuantAS - Off
Main Focus for last year:
- Final results concerning additional mixing of offshore windpark foundations in the Western Baltic Sea (publication in preparation)
- Model nesting: 3D structure development of dense bottom currents in channels (Kriegers Flak North and Bornholm Channel) (publication in preparation)
- Passive Tracer study (correlations for propagation time of dense bottom currents) (publication in preparation)
QuantAS - Off
Main Focus for last year:
QuantAS - Off
Main Focus for last year:
- Final results concerning additional mixing of offshore windpark foundations in the Western Baltic Sea (publication in preparation)
- Model nesting: 3D structure development of dense bottom currents in channels (Kriegers Flak North and Bornholm Channel) (publication in preparation)
- Passive Tracer study (correlations for propagation time of dense bottom currents) (publication in preparation)
Rennau, H., and H. Burchard, Quantitative analysis of numerically induced mixing in a coastal model application, Ocean Dynamics, submitted December 2008.
Burchard, H., and H. Rennau, Comparative quantification of physically and numerically induced mixing in ocean models, Ocean Modelling, 20, 293-311, 2008.
Burchard, H., F. Janssen, K. Bolding, L. Umlauf, and H. Rennau, Model simulations of dense bottom currents in the Western Baltic Sea, Cont. Shelf Res., 29, 205-220, 2009.
Fehmarn Belt Project