The Turkish Straits System - utmea

The Turkish Straits System:
A Review of Mechanisms and Functioning
ENEA, Roma, 13 December 2012
Emin Özsoy, Adil Sözer, Özgür Gürses
Institute of Marine Sciences,
Middle East Technical University,
Erdemli, Mersin
Turkey
at the center stage of
climate variability
in the “Seas of the
Old World”
ENERGY CORRIDORS,
MARINE TRANSPORT
AND ASSOCIATED RISKS
THE ROLE OF TURKISH
STRAITS SYSTEM
The famous ‘crazy project’ ! – Kanal İstanbul !
Wide
Straits in Europe
Narrow
Science of the seas:
starts with navigation
Kristof Kolomb - Cristoforo Colombo - Chios 1474 - America 1492
Piri Reis 1465 - 1554 - Mediterranean - Indian Ocean
First reference to tides in relation to moon - ‘Bahriye’ - 1526
Galileo (1564-1642) - tide related to sun - 1632
Isaac Newton (1642-1727) - first scientific theory of tides - 1686
Bosphorus:
Luigi Ferdinando Marsili (1658-1730)
Bosphorus - ‘Osservazioni intorno al Bosforo Tracio’ - 1681
Histoire physique de la mer - 1725
Danube - 1732
Spratt 1870, Wharton 1872, Makaroff, 1881, Magnaghi 1882,
Gueydon 1886, Spindler 1894, Nielsen 1910, Merz 1917,
Möller 1928
Kosswig (1903-1982) - first marine science effort in Turkey
Ulyott, Ilgaz, Pektaş 1943-1956
Defant 1961, Carruthers 1963, Özturgut 1964, Bogdanova 1961,
……. Until today
Luigi Ferdinando Marsili
in İstanbul
- his first experiments in the Bosphorus -,
- his life and times Emin Özsoy, Nadia Pinardi, Franca
Moroni
(IMS-METU, Erdemli; UB, Bologna)
L. F. Marsili 1658 - 1730
Turkish Straits System
Interaction with adjacent Seas
Forcing from (adjacent basins) :
- sea level
- barometric pressure
- wind setup
- water balance R+P-E
Time scales:
Bosphorus: Transit time < 1/2 day
Dardanelles: Transit time ~ few days
Black Sea: residence time 1-5yr for CIL, >2000yr for bottom
Marmara Sea: residence time 3mo for upper, 6-12yr for lower layer
Mediterranean: residence time ~100 yr
Forcing: < daily - multidecadal
deep bathymetry adjoining wide shelf areas, interconnected by straits, canyons
Economic,
Strategic
importance
Water balance
Ünlüata et al., 1990
Major traffic route
Oil transport
Bathymetry
(
b
)
Turkish
Straits
(a System
)
(c
)
Satellite chlorophyll
EU Project Sesame
Ümit Ünlüata cruises
April 2008
Chlorophyll fluorescence
thermal image
sar image
MODIS image
Physical complexity
Seasonal and
interannual
variability
in Black Sea
water budget
Upper 10 m average salinity from available station data
At Bosphorus entrance
(a)
(b)
(a)
(b)
(c)
(d)
MAXIMAL EXCHANGE THEORY
Bosphorus exchange flow, Özsoy et al., 1998
Marmara Bosphorus Black Sea
R/V BİLİM data,
Sep1994 with
Michael Gregg U.
Washington
contraction
sill
Hydraulic controls ?
Özsoy et al., 2001
Entrainment
fluxes
normal
lower layer blocked
Bosphorus ADCP measurements
Bosphorus CTD measurements
normal
upper layer blocked
lower layer blocked
Turkish Straits System and
northern Aegean Sea exchange
MCIW
CIW
MW
Dardanelles Marmara
Strait
Sea
Bosphorus Black
Strait
Sea
upper layer circulation
(Beşiktepe et al. 1994)
lower layer circulation
Salinity, April 1995
(Beşiktepe, 2000)
Gravity currents, Hüsrevoğlu, 1999
Su seviyesi, meteoroloji,
Deniz suyu özellikleri
Kıyısal istasyonları:
9 + 5 + 3 = 17
kıyısal istasyon:
İğneada
Şile
Sarıyer
Anadolukavağı
Haliç
Pendik
Yalova
Marmara Ereğlisi
Erdek
Gökçeada
Aksaz
Bozyazı
Taşucu
Erdemli
İskenderun
Girne
Magosa
Kıyı istasyonları
gözlem sisteminden
elde edilen
2008 yılı
su seviyesi
değişimleri
Gökçeada
Coastal station
cabled ADCP system
real-time measurements
Blocking of the upper
layer flow
collaboration: Tamay Özgökmen
University of Miami RSMAS
Real B(x,z) for the Bosphorus Strait
Density distribution across Bosphorus Strait
Ilıcak, Özgökmen, Özsoy, Fischer, 2009. Non-hydrostatic
Modeling of Exchange Flows Across Complex Geometries,
Submitted - Ocean Modelling
Tamay Özgökmen (RSMAS, Miami)
ROMS OCEAN MODEL
BOSPHORUS (IDEALIZED CASE)‫‏‬
ROMS OCEAN MODEL
BOSPHORUS

Irregular bathymetry and coastline

Open boundary conditions

Complex physical dynamics

High resolution grid
very small time-step, dt
 time consuming development,
sensitivity tests, pre, post processing

ROMS OCEAN MODEL
BOSPHORUS
3D Model results (Sözer, 2012) vs.
real world measurements (Özsoy et al. 2001)
dx=45m,dy=45m,35 vertical levels.
LMD turbulence closure
(a)
(b)
(c)
(a
)
(b
)
(c
)
Energy Dissipation (loss)
Sözer (2012)
Model results versus ADCP and sea level measurements
Sözer (2012) 3-D model results
Tusak (2012) Analyses from 4years of measurements
Özsoy and Latif (1994-2000) R/V BİLİM on board ADCP measurements
Merz (1917-1918) measurements)
(a)
(b)
(c)
Dardanelles Strait Model
ROMS
Resolution: dx=100m, dy=200m
Dardanelles ADCP
Murat Gündüz, Hycom
Murat
Gündüz,
2009
Demyshev and Dovgaya, MHI
20 year integration !
Without wind
With wind
Chiggiato
et al.
2012
Turkish Straits System with Finite Element Ocean Model
Özgür GÜRSES*, Emin Özsoy*, Ralph Timmermann
IMS-METU* / AWI
This April 7, 2000 image of Istanbul, Turkey shows a 21 by 24 km Advanced Spaceborne Thermal Emission and Reflection
Radiometer (ASTER) sub-scene in the visible and infrared channels. Vegetation appears red, and urban areas blue-green.
http://eoimages.gsfc.nasa.gov/images/imagerecords/0/846/aster_istanbul_lrg.jpg
FESOM
I. The ocean component: FEOM
hydrostatic primitive equation
OGCM
(Danilov et al. 2004, Wang et al.,
2008, Timmermann et al., 2009)
continuous linear basis functions
triangles in 2D
i
ui, hi: nodal values,
N
N
N
u= ∑ ui ϕ i ; m=∑ mi ϕ i ; a=∑ ai ϕ i ;
1
tetrahedra or prism in 3D
different grid types (z-level +
shaved cells; sigma; hybrid)
1
1
ϕi
base functions
N
N
N
1
1
1
u=h∑ ui ϕ i ; m=∑ mi ϕ hi ; a=∑ ai ϕ i ;
Realistic Case Study
Number of Surface Nodes: 11418
Number of Surface Elements: 21820
Number of Vertical Levels: 29
Time Step = 20 s. (5 s.)
EAST-WEST SECTION
TNoL6
BOSPHORUS
DARDANELLES
SURFACE
100 m.
Non-hydrostatic and high resolution modeling of
the Gibraltar Strait
Gianmaria Sannino1
gianmaria.sannino@enea.it
L. Pratt3,
J.C. Sánchez Garrido2
Environment and Energy Modeling Unit
1
Italian Agency for
New Technologies,
Energy and Sustainable
Economic Development
Belgrade 21 May 2012
2
3
Black Sea and the Turkish Straits System
Özsoy et al., 2001
Özsoy et al., 1993
CIRCULATION
The monthly mean atmospheric circulation in the Black Sea region has a cyclonic
character throughout the year. The positive wind stress curl and the buoyancy
contrast between the fresh water inflow from rivers and the salt water supply through
the Bosphorus Strait induce a cyclonic circulation in the sea.
A permanent feature of the upper layer circulation is the Rim Current, encircling the
entire Black Sea and forming a large-scale cyclonic gyre (Neumann, 1944). The
adjustment of the currents to the shape of the basin with enlarged eastern and
western halves results in the appearance of two smaller cyclonic gyres in the
western and the eastern parts of the basin. The Rim Current encircles these gyres
and sweeps by the smaller gyres trapped near the coast.
STRATIFICATION
Typical profiles of temperature, salinity and density show a well-pronounced
permanent pycnocline, which is situated at a depth of 150-300m. Density
stratification is determined mainly by salinity. The deep-sea salinity is near 22.5 ppt
against 18-18.5 ppt on the surface. Temperature input significant in the upper layer
where is observed a distinctive feature of the Black Sea thermal stratification – the
cold intermediate layer. SST is varying seasonally from 8C up to 30C. Deep
temperature is about 8.5C. The internal Rossby radius is about 25 km in the deepsea area.
Black Sea Hydrological Cycle:
- Closed Basin (constrained by the exchange at the Turkish Straits System)
- Continent-size catchment dominated by large rivers in a climate sensitive region
- Sea effect: air-sea exchange of a landlocked basin of continental/marine climate
- Upwelling systems, boundary current jets and eddies, high dynamical variability
- Ice covered north-western shelf and shallow Azov Sea in winter
- Sensitive ecosystem, river dominated, open to Mediterranean influence
18-22 Aug 2012
cumulative precipitation
Floods in eastern Black Sea
Sea water temperature
Coastal stations
Relative humidity
and surface wind
cool, dry winds
moisture flux
uplifting and
saturation
by orography
moisture flux
Forest fires
In the Aegean
Coastal upwelling, model
Upwelling events
Upwelling winds
Etesian winds
(Aegean forest fires)
Coastal upwelling, satellite
Fish kills by upwe
Emiliana Huxleyi Bloom
‘Marine Layer’ (atmospheric inversion) at İnebolu coastal upwelling area,
Black Sea
Photo Sinan Çevik
Wintertime events: sea effect snow
Southward moisture transport from the Black Sea
creates snow blizzards in the absence of a storm…
Feb 02, 2012
Ice NWS
Jan 25, 2010
Ice cover
Azov Sea
Ice NWS
Feb 10, 2012
Ice cover
Azov Sea
Wintertime moisture transport
Cold dry winds from the north picking up
Moisture from the warm Black Sea
Turkish Straits Problem
Closing of the hydrological cycle
Ice floes from the Black Sea in the Bosphorus
Potential Bosphorus Strait
impact to the mesoscale
dynamics
Modeling of the Black Sea in MyOcean
with Bosphorus Strait exchange
Gennady Korotaev, Artem Mizyuk
Potential Bosphorus Strait impact to the
mesoscale dynamics
fast waves along periphery
[Вертикальная скорость] = [10-4 см/c]; [уровень моря] = [см]
The Black Sea NEMO configuration, MHI
A. Mizyuk, G. Korotaev
Model grid in the Black Sea configuration and resolution
NEMO v. 3.3
5×5 km (size 238×132), 37 z-levels, partial step
(hyperbolic tangent stretching, Madec et al., 1998).
10 minutes time step
The bathymetry based on the data prepared in MHI with maximum depth of 2202 m
Filtered time scheme (key_dynspg_flt)
Mellor-Yamada 2.5 vertical mixing (key_zdfgls)
Biharmonic lateral mixing for tracers and momentum
MUSCL scheme for advection
Open boundary for Bosphorus
Rivers:
Danube, Dnestr, Dnepr,
Kodori, Inguri, Rioni,
Yeşilırmak, Kızılırmak,
Sakarya
+ Kerch strait
Known climatic volume discharge transformed to velocity with
climatic temperature and salinity values used for open boundary
conditions (3 gridpoints width south open boundary)
Possible solutions for adding Sea
of Marmara
Addition to the BlackSea-Azov configuration
with Dardanelles parametrization and explicit
Bosphorus strait (3 gridpoints)
Use of NEMO AGRIF
zoom for evaluation of
dynamics in the
Bosphorus
IMS-METU BLACK SEA FORECAST MODEL - POM
Bathymetry was extracted from Gebco which has an horizontal resolution
in x and y is one minute (1/60°x1/60°) for the Black and Azov Seas.
horizontal resolution of 2.5 km in both x and y directions with 20 sigma layers
outflow of the rivers parameterized by salt flux boundary conditions
8 rivers of the Black and Azov seas implemented
The rivers are Danube, Dnieper, Dniester, Rioni, Kızılırmak, Sakarya, Don and Kuban.
The monthly average rivers discharge from
Global River Discharge Database, Version 1.1
(Riv.Dis.v10 supplement at http://www.rivdis.sr.unh.edu).
Surface atmospheric data 6 hr, 0.05o horizontal-resolution, University of Athens IASA
The surface fluxes computed from Monin-Obukhov atmospheric boundary layer model
interactively using the atmospheric variables and sea surface temperature and salinity
developed in the ocean model.
The Bosphorus Channel was described in the model as 5 grid points in width (12.5 km)
and about 17 grid points in length (42.5 km) with maximum depth of 60 m. At the southern
open boundary, we impose for the normal velocity of 0.1 m/s that corresponds to net flux
and relax T,S profiles to adjust inflow-outflow.
IMS-METU
Black Sea forecasts, POM
The Black Sea NEMO configuration, IMS-METU
NEMO 3.3.1
Model of the Black sea with the Azov sea
Domain: N40.55-N47.2, E26.34-42.22
Horizontal resolution: 1/12 degree
Z coordinate, partial steps, vertical resolution: 42 levels
Dynamical time step: 270s, number of barotropic time steps: 50, time step: 5.4s
Bathymetry: GEBCO, max. depth 2250m
Surface atmospheric forcing: ECMWF ERA Interim, 3hr temporal resolution
clio bulk formulation
Runoff: Danube, Dniestr, Dniepr and Don
Constant geothermal flux at the bottom (40.10-3 W/m2)
Open boundary condition: Vertical profiles of temperature and salinity
at 1 point located at the northern sill of the strait of the Bosphorus
Initial conditions: Levitus temperature and salinity files.
Lateral diffusion: Laplacian for the tracer (rn_aht_0 = 100. m2/s)
Bilaplacian for the momentum (rn_ahm_0_blp = -7.109 m4/s)
Generic Length Scale model (gls), Double Diffusion Mixing model (ddm)
List of the keys: key_mpp_mpi, key_ldfslp, key_dynspg_ts, key_trabbl, key_trabbc,
key_bdy, key_zdfgls, key_zdfddm