Dynamics of dense overflows – detailed studies from the Western Baltic Sea
Hans Burchard1, Hans Ulrich Lass1, Lars Umlauf1, Karsten Bolding2, Frank Janssen3, Volker Mohrholz1, Hannes Rennau1
1. Baltic Sea Research Institute Warnemünde
2. Bolding & Burchard Hydrodynamics3. Federal Maritime and Hydrographic Agency
Oder: Wie Jürgen Sellschopp das Modellieren schätzen lernte.
Das kriegen die niemodelliert !
For the investigation of this problem, the international project cluster QuantAS(Quantification of water mass transformation processes in the Akona Sea) was set up.
Graphics: Jan Donath (IOW)
Photo: Frank Richter (Uni Rostock) © NDR
Uli Lass (2002):
„Wind turbine foundationsmay mix up dense bottom currents.“
Establishing the QuantAS Consortium in May 2003
...Treppenabsatzfoto Nr. 257 …
Interessantes Projekt auch aus der Sicht der FWG.
Wir könnten für Anfang 2004 mit Schiffszeit
dabei sein.
Baltic Sea bathymetry
Entire Baltic
Belt Sea / Western Baltic
Western Baltic Sea: Bathymetry
Darss Sill: 19 m
+
Drogden Sill: 8 m
+MARNET (IOW/BSH)
Farvandsvæsenet
baroclinic barotropic
Inflows over Drogden Sill
surface
bottom
Graphics: Frank Janssen (BSH)
Where does the Sound plume go ?
?
x
y
U-V
Dense bottom currents:
Balance between rotation,friction and pressure gradient
GETM is a 3D numerical model for estuarine,coastal and shelf sea hydrodynamics with applications to the
• Tidal Elbe • Wadden Sea• Limfjord• Lake of Geneva, • Western Baltic Sea,• North Sea – Baltic Sea system• …
Lass die doch modellieren. Wir hocken lieber im
Container und pflegen unsere
Feldmessungen.
5 days
15 days
31 days
Sound lock-exchange experiment with GETM
Bottom salinity: 8 – 25 psu
Kann das denn
angehen ?
Searching for the plume
Plume coming down from the Sound (Feb‘ 2004)
Plume passing Kriegers Flak (Feb‘ 2004)
Profiles through plumenorth of Kriegers Flak
(Feb‘ 2004)
Realistic simulation of the Februar 2004 plume
Baltic Sea model:Baltic Sea MOM-3.1 model 3 nm horizontal resolution77 vertical (geopotential) grid layersMeteo forcing from ECWMF Reanalysis Project ERA40 (until August 2002)German Weather Service Global Model with a resolution (from September 2002).Boundary conditions stored for elevation, temperature and salinity at 57 deg 30‘ N (Kattegat) and 16 deg 30‘ E (east of Bornholm Sea)
Western Baltic Sea model: Sim-time: September 1, 2003 - May 1, 2004Forced by German Weather Service Local Model (resolution: 7 km and 3 hours)Lateral boundary conditions from Baltic Sea model Resolution: 1/2 nm in the horizontal, 50 general vertical coordinate layersTime step was 10 s for barotropic and 300 s for baroclinic mode.
Domain decomposition for Western Baltic Sea model
Bottom salinity in Arkona Sea
Salt transport across Drogden Sill
Model validation: Darss Sill
Model validation: Arkona Buoy
Feb. 2004 section
across Kriegers Flak
November 2005: More detailed QuantAS observations
Nov 2005: Velocity structure of dense bottom current
Ship A:TL-ADCP
Ship B: Microstructure
View
1 km
Flow
Eastcomp.
Northcomp.
Can we explain the flow structure ?
T2:Turbulence Measurements
enhanced turbulencein down-welling region
interfacial turbulence
quiet core
BBL Turbulence
21
3
N
Lo
Ozmidov Scale:
Ozmidov Scale
Dissipation Rate
GETM 2DV Slice Model: Transverse gravity current structure
Na, Jürgen, war das nicht ne schöne Zeit,
damals 03 – 07 ?Ach ja … und
aus dem Modell konnte man ja so richtig was
lernen …
… dann kann ich
ja in Rente
gehen …