3D Visualization and Analysis of 3D Visualization and Analysis of Topographic and Geologic Oceanographic Topographic and Geologic Oceanographic

Data in the NW Aegean SeaData in the NW Aegean Sea

A. Karageorgis, P. Drakopoulou & Chr. AnagnostouA. Karageorgis, P. Drakopoulou & Chr. Anagnostou

The EU The EU MAST-III ELOISEMAST-III ELOISE Metro-MedMetro-Med project project(Contract No: CT 960049)(Contract No: CT 960049)

Collects data from the fields:

In an effort to organize, analyze, compare and finally to explore

the data set, we have utilized the Arc/Info GIS platform for the

development of an application named “Metro-Med GIS”

• Physical• Geological• Biological and• Chemical Oceanography

Metro-Med Multidisciplinary CruisesMetro-Med Multidisciplinary Cruises

1997

1998

The Working AreaThe Working Area

Marine area : Thermaikos Gulf & Sporades basin

in NW Aegean Sea(39o 00΄N - 22o 30΄E, 40o 40΄N - 24o 30΄E)

Drainage basin : study the marine area as an integrated

system with the surrounding land,

since terrestrial input in fresh water,

sediments, nutrients, pollutants is of

major importance.

The Working AreaThe Working Area

The Working AreaThe Working Area

Data projection ...Data projection ...

Greek Geodetic Reference System 1987:

• Transverse Mercator projection

• central meridian λo = 24o

• scale’s coefficient = 0.9996• constant 500,000 is added to the x-axis values

* The reference points use for the data transformation,

produced an RMS (Residual Mean square) Error

between 0.002 and 0.017

The area under investigation was separated The area under investigation was separated inin three zones ...

The cartographic data baseThe cartographic data base

comprises the following categories - layers of

information:

• Bathymetry• Hypsometry• Hydrography• Political - Administrative borders• Road Network• Urban Area

The DEM of the whole areaThe DEM of the whole area ...

-1000102030405060708090100150200300400500600700800900100011001200130014001500

meters

Metro-Med Digital Bathymetric Map of the Thermaikos Gulf and the Sporades Basin

Area(km2)

Volume(km3)

Shelf

Basin

Total

5,350 430

5,250 3,570

10,600 4,000

• riverine supply

– proximity to the sources

– water circulation

– bottom topography

• Thessaloniki city supply

• stratification

Factors controlling SPM distribution:

Particle transport and depositionParticle transport and deposition

• transport along the western coast (SE)

• resuspension and deposition mechanisms

closely related to the distance from the river

mouths

• absence of detached layers towards the basin

• shelf acts as a sediment trap

Conclusions

• SPM major sources are the rivers Axios, Aliakmonas and Pineios• SPM input is high only during the “wet” seasons• SPM distribution follows the dominant cyclonic cirulation• SPM settles in the shelf• SPM is mainly terrigenous• Sediments distribution follow in general the bathymetry• Sands in the eastern and central part

• lack of input• circulation patterns

• Silt deposition in fron of the river mouths• Clay deposition in the basin• Resuspension possibilities in the western part