Application of Landsat imagery, to verify near shore water circulation of Saronikos gulf, as resulted from numerical modelling

Abstract

Hydrodynamic numerical models nowadays offer great aid when studying the physical behavior of coastal waters. However, the calibration and furthermore the verification of such models, is a difficult process that should be applied carefully, especially when little direct hydrodynamic data has been collected from the study area. This paper suggests a methodology for indirect verification of mathematical coastal circulation models, by means of image processing and interpretation of Landsat's TM reflective bands 3 and 6 imagery. This approach is an efficient practice and is easily available even though no field survey was carried out. This method was successfully applied to Saronikos Gulf and in particular to gulf of Megara, located westwards of Salamis Island, where the dispersion of a plume formed by urban waste waters was examined. The satellite data processing derivatives were found to be in accordance with the results of the circulation simulation and thus the parameters used for the calibration of the model can be considered successfully selected.

The dispersion of 137Cs in a shallow Mediterranean embayment (Saronikos Gulf – Elefsis Bay), estimated inventories and residence times

“…The Saronikos Gulf is one of the most polluted marine regions in Greece as a large amount of industrial and urban sewages end up to its coasts, sometimes without even having been submitted to prior treatment (Zacharias and Fakiris, 2005). Urban sewage of the city of Athens was discharged untreated in the Saronikos Gulf for many years and that was the major reason for its pollution.…”

Vertical Distribution and Chemical Fractionation of Heavy Metals in Dated Sediment Cores from the Saronikos Gulf, Greece

“…Elefsis Bay is one of the most polluted marine areas in Greece, as, for many years, a large amount of industrial waste (from oil refineries, shipyards, chemical plants, food, metal/cement industries, etc.) and urban sewages was discharged into the bay, mostly without any prior treatment [17][18][19]. The eastern part of Elefsis Bay, where the city of Elefsis is located, is characterized by the existence of heavy industry, while the western part of the gulf is industrialized to a lesser extent.…”

“…Elefsis Bay, on the other hand, is one of the most polluted marine areas of Greece, as, for many years, a large amount of industrial waste (from oil refineries, shipyards, chemical plants, food, metal/cement industries, etc.) and sewage has been discharged into the bay, mostly without any prior treatment [17][18][19]. The pollution of Elefsis Bay has been studied since the late 1970s [20,21], and while recovery trends have been observed [19,22], the deterioration of the marine environment was so great that, for example, within twenty years , about 70% of the benthic species had become extinct or their abundance had been dramatically reduced [19].…”

POC and particulate 234Th export fluxes estimated using 234Th/238U disequilibrium in an enclosed Eastern Mediterranean region (Saronikos Gulf and Elefsis Bay, Greece) in seasonal scale

“…Moreover, to determine seasonal variations of POC export from the euphotic zone and particle cycling rates in Saronikos Gulf and Elefsis Bay. Since these marine environments are considered as of the most artificially polluted in Greece (they accept organic loads for a long time period) (Zacharias and Fakiris, 2005), it is really essential to examine if POC levels are enhanced in higher depths, as a result of sinking of particles or other marine processes (i.e., vertical transport).…”